39
40#include "opt_compat.h"
41#include "opt_ddb.h"
42
43#include <sys/param.h>
44#include <sys/systm.h>
45
46#include <sys/conf.h>
47#include <sys/domain.h>
48#include <sys/fcntl.h>
49#include <sys/file.h>
50#include <sys/filedesc.h>
51#include <sys/filio.h>
52#include <sys/jail.h>
53#include <sys/kernel.h>
54#include <sys/limits.h>
55#include <sys/lock.h>
56#include <sys/malloc.h>
57#include <sys/mount.h>
58#include <sys/mqueue.h>
59#include <sys/mutex.h>
60#include <sys/namei.h>
61#include <sys/priv.h>
62#include <sys/proc.h>
63#include <sys/protosw.h>
64#include <sys/resourcevar.h>
65#include <sys/signalvar.h>
66#include <sys/socketvar.h>
67#include <sys/stat.h>
68#include <sys/sx.h>
69#include <sys/syscallsubr.h>
70#include <sys/sysctl.h>
71#include <sys/sysproto.h>
72#include <sys/unistd.h>
73#include <sys/user.h>
74#include <sys/vnode.h>
75
76#include <security/audit/audit.h>
77
78#include <vm/uma.h>
79
80#include <ddb/ddb.h>
81
82static MALLOC_DEFINE(M_FILEDESC, "filedesc", "Open file descriptor table");
83static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "filedesc_to_leader",
84 "file desc to leader structures");
85static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
86
87static uma_zone_t file_zone;
88
89
90/* How to treat 'new' parameter when allocating a fd for do_dup(). */
91enum dup_type { DUP_VARIABLE, DUP_FIXED };
92
93static int do_dup(struct thread *td, enum dup_type type, int old, int new,
94 register_t *retval);
95static int fd_first_free(struct filedesc *, int, int);
96static int fd_last_used(struct filedesc *, int, int);
97static void fdgrowtable(struct filedesc *, int);
98static void fdunused(struct filedesc *fdp, int fd);
99static void fdused(struct filedesc *fdp, int fd);
100
101/*
102 * A process is initially started out with NDFILE descriptors stored within
103 * this structure, selected to be enough for typical applications based on
104 * the historical limit of 20 open files (and the usage of descriptors by
105 * shells). If these descriptors are exhausted, a larger descriptor table
106 * may be allocated, up to a process' resource limit; the internal arrays
107 * are then unused.
108 */
109#define NDFILE 20
110#define NDSLOTSIZE sizeof(NDSLOTTYPE)
111#define NDENTRIES (NDSLOTSIZE * __CHAR_BIT)
112#define NDSLOT(x) ((x) / NDENTRIES)
113#define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES))
114#define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES)
115
116/*
117 * Storage required per open file descriptor.
118 */
119#define OFILESIZE (sizeof(struct file *) + sizeof(char))
120
121/*
122 * Basic allocation of descriptors:
123 * one of the above, plus arrays for NDFILE descriptors.
124 */
125struct filedesc0 {
126 struct filedesc fd_fd;
127 /*
128 * These arrays are used when the number of open files is
129 * <= NDFILE, and are then pointed to by the pointers above.
130 */
131 struct file *fd_dfiles[NDFILE];
132 char fd_dfileflags[NDFILE];
133 NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)];
134};
135
136/*
137 * Descriptor management.
138 */
139volatile int openfiles; /* actual number of open files */
140struct mtx sigio_lock; /* mtx to protect pointers to sigio */
141void (*mq_fdclose)(struct thread *td, int fd, struct file *fp);
142
143/* A mutex to protect the association between a proc and filedesc. */
144static struct mtx fdesc_mtx;
145
146/*
147 * Find the first zero bit in the given bitmap, starting at low and not
148 * exceeding size - 1.
149 */
150static int
151fd_first_free(struct filedesc *fdp, int low, int size)
152{
153 NDSLOTTYPE *map = fdp->fd_map;
154 NDSLOTTYPE mask;
155 int off, maxoff;
156
157 if (low >= size)
158 return (low);
159
160 off = NDSLOT(low);
161 if (low % NDENTRIES) {
162 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES)));
163 if ((mask &= ~map[off]) != 0UL)
164 return (off * NDENTRIES + ffsl(mask) - 1);
165 ++off;
166 }
167 for (maxoff = NDSLOTS(size); off < maxoff; ++off)
168 if (map[off] != ~0UL)
169 return (off * NDENTRIES + ffsl(~map[off]) - 1);
170 return (size);
171}
172
173/*
174 * Find the highest non-zero bit in the given bitmap, starting at low and
175 * not exceeding size - 1.
176 */
177static int
178fd_last_used(struct filedesc *fdp, int low, int size)
179{
180 NDSLOTTYPE *map = fdp->fd_map;
181 NDSLOTTYPE mask;
182 int off, minoff;
183
184 if (low >= size)
185 return (-1);
186
187 off = NDSLOT(size);
188 if (size % NDENTRIES) {
189 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES));
190 if ((mask &= map[off]) != 0)
191 return (off * NDENTRIES + flsl(mask) - 1);
192 --off;
193 }
194 for (minoff = NDSLOT(low); off >= minoff; --off)
195 if (map[off] != 0)
196 return (off * NDENTRIES + flsl(map[off]) - 1);
197 return (low - 1);
198}
199
200static int
201fdisused(struct filedesc *fdp, int fd)
202{
203 KASSERT(fd >= 0 && fd < fdp->fd_nfiles,
204 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles));
205 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0);
206}
207
208/*
209 * Mark a file descriptor as used.
210 */
211static void
212fdused(struct filedesc *fdp, int fd)
213{
214
215 FILEDESC_XLOCK_ASSERT(fdp);
216 KASSERT(!fdisused(fdp, fd),
217 ("fd already used"));
218
219 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd);
220 if (fd > fdp->fd_lastfile)
221 fdp->fd_lastfile = fd;
222 if (fd == fdp->fd_freefile)
223 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles);
224}
225
226/*
227 * Mark a file descriptor as unused.
228 */
229static void
230fdunused(struct filedesc *fdp, int fd)
231{
232
233 FILEDESC_XLOCK_ASSERT(fdp);
234 KASSERT(fdisused(fdp, fd),
235 ("fd is already unused"));
236 KASSERT(fdp->fd_ofiles[fd] == NULL,
237 ("fd is still in use"));
238
239 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd);
240 if (fd < fdp->fd_freefile)
241 fdp->fd_freefile = fd;
242 if (fd == fdp->fd_lastfile)
243 fdp->fd_lastfile = fd_last_used(fdp, 0, fd);
244}
245
246/*
247 * System calls on descriptors.
248 */
249#ifndef _SYS_SYSPROTO_H_
250struct getdtablesize_args {
251 int dummy;
252};
253#endif
254/* ARGSUSED */
255int
256getdtablesize(struct thread *td, struct getdtablesize_args *uap)
257{
258 struct proc *p = td->td_proc;
259
260 PROC_LOCK(p);
261 td->td_retval[0] =
262 min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
263 PROC_UNLOCK(p);
264 return (0);
265}
266
267/*
268 * Duplicate a file descriptor to a particular value.
269 *
270 * Note: keep in mind that a potential race condition exists when closing
271 * descriptors from a shared descriptor table (via rfork).
272 */
273#ifndef _SYS_SYSPROTO_H_
274struct dup2_args {
275 u_int from;
276 u_int to;
277};
278#endif
279/* ARGSUSED */
280int
281dup2(struct thread *td, struct dup2_args *uap)
282{
283
284 return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to,
285 td->td_retval));
286}
287
288/*
289 * Duplicate a file descriptor.
290 */
291#ifndef _SYS_SYSPROTO_H_
292struct dup_args {
293 u_int fd;
294};
295#endif
296/* ARGSUSED */
297int
298dup(struct thread *td, struct dup_args *uap)
299{
300
301 return (do_dup(td, DUP_VARIABLE, (int)uap->fd, 0, td->td_retval));
302}
303
304/*
305 * The file control system call.
306 */
307#ifndef _SYS_SYSPROTO_H_
308struct fcntl_args {
309 int fd;
310 int cmd;
311 long arg;
312};
313#endif
314/* ARGSUSED */
315int
316fcntl(struct thread *td, struct fcntl_args *uap)
317{
318 struct flock fl;
319 intptr_t arg;
320 int error;
321
322 error = 0;
323 switch (uap->cmd) {
324 case F_GETLK:
325 case F_SETLK:
326 case F_SETLKW:
327 error = copyin((void *)(intptr_t)uap->arg, &fl, sizeof(fl));
328 arg = (intptr_t)&fl;
329 break;
330 default:
331 arg = uap->arg;
332 break;
333 }
334 if (error)
335 return (error);
336 error = kern_fcntl(td, uap->fd, uap->cmd, arg);
337 if (error)
338 return (error);
339 if (uap->cmd == F_GETLK)
340 error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl));
341 return (error);
342}
343
344static inline struct file *
345fdtofp(int fd, struct filedesc *fdp)
346{
347 struct file *fp;
348
349 FILEDESC_LOCK_ASSERT(fdp);
350 if ((unsigned)fd >= fdp->fd_nfiles ||
351 (fp = fdp->fd_ofiles[fd]) == NULL)
352 return (NULL);
353 return (fp);
354}
355
356int
357kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg)
358{
359 struct filedesc *fdp;
360 struct flock *flp;
361 struct file *fp;
362 struct proc *p;
363 char *pop;
364 struct vnode *vp;
365 u_int newmin;
366 int error, flg, tmp;
367 int vfslocked;
368
369 vfslocked = 0;
370 error = 0;
371 flg = F_POSIX;
372 p = td->td_proc;
373 fdp = p->p_fd;
374
375 switch (cmd) {
376 case F_DUPFD:
377 FILEDESC_SLOCK(fdp);
378 if ((fp = fdtofp(fd, fdp)) == NULL) {
379 FILEDESC_SUNLOCK(fdp);
380 error = EBADF;
381 break;
382 }
383 FILEDESC_SUNLOCK(fdp);
384 newmin = arg;
385 PROC_LOCK(p);
386 if (newmin >= lim_cur(p, RLIMIT_NOFILE) ||
387 newmin >= maxfilesperproc) {
388 PROC_UNLOCK(p);
389 error = EINVAL;
390 break;
391 }
392 PROC_UNLOCK(p);
393 error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval);
394 break;
395
396 case F_GETFD:
397 FILEDESC_SLOCK(fdp);
398 if ((fp = fdtofp(fd, fdp)) == NULL) {
399 FILEDESC_SUNLOCK(fdp);
400 error = EBADF;
401 break;
402 }
403 pop = &fdp->fd_ofileflags[fd];
404 td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0;
405 FILEDESC_SUNLOCK(fdp);
406 break;
407
408 case F_SETFD:
409 FILEDESC_XLOCK(fdp);
410 if ((fp = fdtofp(fd, fdp)) == NULL) {
411 FILEDESC_XUNLOCK(fdp);
412 error = EBADF;
413 break;
414 }
415 pop = &fdp->fd_ofileflags[fd];
416 *pop = (*pop &~ UF_EXCLOSE) |
417 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0);
418 FILEDESC_XUNLOCK(fdp);
419 break;
420
421 case F_GETFL:
422 FILEDESC_SLOCK(fdp);
423 if ((fp = fdtofp(fd, fdp)) == NULL) {
424 FILEDESC_SUNLOCK(fdp);
425 error = EBADF;
426 break;
427 }
428 td->td_retval[0] = OFLAGS(fp->f_flag);
429 FILEDESC_SUNLOCK(fdp);
430 break;
431
432 case F_SETFL:
433 FILEDESC_SLOCK(fdp);
434 if ((fp = fdtofp(fd, fdp)) == NULL) {
435 FILEDESC_SUNLOCK(fdp);
436 error = EBADF;
437 break;
438 }
439 fhold(fp);
440 FILEDESC_SUNLOCK(fdp);
441 do {
442 tmp = flg = fp->f_flag;
443 tmp &= ~FCNTLFLAGS;
444 tmp |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS;
445 } while(atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0);
446 tmp = fp->f_flag & FNONBLOCK;
447 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
448 if (error) {
449 fdrop(fp, td);
450 break;
451 }
452 tmp = fp->f_flag & FASYNC;
453 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td);
454 if (error == 0) {
455 fdrop(fp, td);
456 break;
457 }
458 atomic_clear_int(&fp->f_flag, FNONBLOCK);
459 tmp = 0;
460 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
461 fdrop(fp, td);
462 break;
463
464 case F_GETOWN:
465 FILEDESC_SLOCK(fdp);
466 if ((fp = fdtofp(fd, fdp)) == NULL) {
467 FILEDESC_SUNLOCK(fdp);
468 error = EBADF;
469 break;
470 }
471 fhold(fp);
472 FILEDESC_SUNLOCK(fdp);
473 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td);
474 if (error == 0)
475 td->td_retval[0] = tmp;
476 fdrop(fp, td);
477 break;
478
479 case F_SETOWN:
480 FILEDESC_SLOCK(fdp);
481 if ((fp = fdtofp(fd, fdp)) == NULL) {
482 FILEDESC_SUNLOCK(fdp);
483 error = EBADF;
484 break;
485 }
486 fhold(fp);
487 FILEDESC_SUNLOCK(fdp);
488 tmp = arg;
489 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td);
490 fdrop(fp, td);
491 break;
492
493 case F_SETLKW:
494 flg |= F_WAIT;
495 /* FALLTHROUGH F_SETLK */
496
497 case F_SETLK:
498 FILEDESC_SLOCK(fdp);
499 if ((fp = fdtofp(fd, fdp)) == NULL) {
500 FILEDESC_SUNLOCK(fdp);
501 error = EBADF;
502 break;
503 }
504 if (fp->f_type != DTYPE_VNODE) {
505 FILEDESC_SUNLOCK(fdp);
506 error = EBADF;
507 break;
508 }
509 flp = (struct flock *)arg;
510 if (flp->l_whence == SEEK_CUR) {
511 if (fp->f_offset < 0 ||
512 (flp->l_start > 0 &&
513 fp->f_offset > OFF_MAX - flp->l_start)) {
514 FILEDESC_SUNLOCK(fdp);
515 error = EOVERFLOW;
516 break;
517 }
518 flp->l_start += fp->f_offset;
519 }
520
521 /*
522 * VOP_ADVLOCK() may block.
523 */
524 fhold(fp);
525 FILEDESC_SUNLOCK(fdp);
526 vp = fp->f_vnode;
527 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
528 switch (flp->l_type) {
529 case F_RDLCK:
530 if ((fp->f_flag & FREAD) == 0) {
531 error = EBADF;
532 break;
533 }
534 PROC_LOCK(p->p_leader);
535 p->p_leader->p_flag |= P_ADVLOCK;
536 PROC_UNLOCK(p->p_leader);
537 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
538 flp, flg);
539 break;
540 case F_WRLCK:
541 if ((fp->f_flag & FWRITE) == 0) {
542 error = EBADF;
543 break;
544 }
545 PROC_LOCK(p->p_leader);
546 p->p_leader->p_flag |= P_ADVLOCK;
547 PROC_UNLOCK(p->p_leader);
548 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
549 flp, flg);
550 break;
551 case F_UNLCK:
552 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
553 flp, F_POSIX);
554 break;
555 default:
556 error = EINVAL;
557 break;
558 }
559 VFS_UNLOCK_GIANT(vfslocked);
560 vfslocked = 0;
561 /* Check for race with close */
562 FILEDESC_SLOCK(fdp);
563 if ((unsigned) fd >= fdp->fd_nfiles ||
564 fp != fdp->fd_ofiles[fd]) {
565 FILEDESC_SUNLOCK(fdp);
566 flp->l_whence = SEEK_SET;
567 flp->l_start = 0;
568 flp->l_len = 0;
569 flp->l_type = F_UNLCK;
570 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
571 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
572 F_UNLCK, flp, F_POSIX);
573 VFS_UNLOCK_GIANT(vfslocked);
574 vfslocked = 0;
575 } else
576 FILEDESC_SUNLOCK(fdp);
577 fdrop(fp, td);
578 break;
579
580 case F_GETLK:
581 FILEDESC_SLOCK(fdp);
582 if ((fp = fdtofp(fd, fdp)) == NULL) {
583 FILEDESC_SUNLOCK(fdp);
584 error = EBADF;
585 break;
586 }
587 if (fp->f_type != DTYPE_VNODE) {
588 FILEDESC_SUNLOCK(fdp);
589 error = EBADF;
590 break;
591 }
592 flp = (struct flock *)arg;
593 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK &&
594 flp->l_type != F_UNLCK) {
595 FILEDESC_SUNLOCK(fdp);
596 error = EINVAL;
597 break;
598 }
599 if (flp->l_whence == SEEK_CUR) {
600 if ((flp->l_start > 0 &&
601 fp->f_offset > OFF_MAX - flp->l_start) ||
602 (flp->l_start < 0 &&
603 fp->f_offset < OFF_MIN - flp->l_start)) {
604 FILEDESC_SUNLOCK(fdp);
605 error = EOVERFLOW;
606 break;
607 }
608 flp->l_start += fp->f_offset;
609 }
610 /*
611 * VOP_ADVLOCK() may block.
612 */
613 fhold(fp);
614 FILEDESC_SUNLOCK(fdp);
615 vp = fp->f_vnode;
616 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
617 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp,
618 F_POSIX);
619 VFS_UNLOCK_GIANT(vfslocked);
620 vfslocked = 0;
621 fdrop(fp, td);
622 break;
623 default:
624 error = EINVAL;
625 break;
626 }
627 VFS_UNLOCK_GIANT(vfslocked);
628 return (error);
629}
630
631/*
632 * Common code for dup, dup2, and fcntl(F_DUPFD).
633 */
634static int
635do_dup(struct thread *td, enum dup_type type, int old, int new,
636 register_t *retval)
637{
638 struct filedesc *fdp;
639 struct proc *p;
640 struct file *fp;
641 struct file *delfp;
642 int error, holdleaders, maxfd;
643
644 KASSERT((type == DUP_VARIABLE || type == DUP_FIXED),
645 ("invalid dup type %d", type));
646
647 p = td->td_proc;
648 fdp = p->p_fd;
649
650 /*
651 * Verify we have a valid descriptor to dup from and possibly to
652 * dup to.
653 */
654 if (old < 0 || new < 0)
655 return (EBADF);
656 PROC_LOCK(p);
657 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
658 PROC_UNLOCK(p);
659 if (new >= maxfd)
660 return (EMFILE);
661
662 FILEDESC_XLOCK(fdp);
663 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) {
664 FILEDESC_XUNLOCK(fdp);
665 return (EBADF);
666 }
667 if (type == DUP_FIXED && old == new) {
668 *retval = new;
669 FILEDESC_XUNLOCK(fdp);
670 return (0);
671 }
672 fp = fdp->fd_ofiles[old];
673 fhold(fp);
674
675 /*
676 * If the caller specified a file descriptor, make sure the file
677 * table is large enough to hold it, and grab it. Otherwise, just
678 * allocate a new descriptor the usual way. Since the filedesc
679 * lock may be temporarily dropped in the process, we have to look
680 * out for a race.
681 */
682 if (type == DUP_FIXED) {
683 if (new >= fdp->fd_nfiles)
684 fdgrowtable(fdp, new + 1);
685 if (fdp->fd_ofiles[new] == NULL)
686 fdused(fdp, new);
687 } else {
688 if ((error = fdalloc(td, new, &new)) != 0) {
689 FILEDESC_XUNLOCK(fdp);
690 fdrop(fp, td);
691 return (error);
692 }
693 }
694
695 /*
696 * If the old file changed out from under us then treat it as a
697 * bad file descriptor. Userland should do its own locking to
698 * avoid this case.
699 */
700 if (fdp->fd_ofiles[old] != fp) {
701 /* we've allocated a descriptor which we won't use */
702 if (fdp->fd_ofiles[new] == NULL)
703 fdunused(fdp, new);
704 FILEDESC_XUNLOCK(fdp);
705 fdrop(fp, td);
706 return (EBADF);
707 }
708 KASSERT(old != new,
709 ("new fd is same as old"));
710
711 /*
712 * Save info on the descriptor being overwritten. We cannot close
713 * it without introducing an ownership race for the slot, since we
714 * need to drop the filedesc lock to call closef().
715 *
716 * XXX this duplicates parts of close().
717 */
718 delfp = fdp->fd_ofiles[new];
719 holdleaders = 0;
720 if (delfp != NULL) {
721 if (td->td_proc->p_fdtol != NULL) {
722 /*
723 * Ask fdfree() to sleep to ensure that all relevant
724 * process leaders can be traversed in closef().
725 */
726 fdp->fd_holdleaderscount++;
727 holdleaders = 1;
728 }
729 }
730
731 /*
732 * Duplicate the source descriptor
733 */
734 fdp->fd_ofiles[new] = fp;
735 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
736 if (new > fdp->fd_lastfile)
737 fdp->fd_lastfile = new;
738 *retval = new;
739
740 /*
741 * If we dup'd over a valid file, we now own the reference to it
742 * and must dispose of it using closef() semantics (as if a
743 * close() were performed on it).
744 *
745 * XXX this duplicates parts of close().
746 */
747 if (delfp != NULL) {
748 knote_fdclose(td, new);
749 if (delfp->f_type == DTYPE_MQUEUE)
750 mq_fdclose(td, new, delfp);
751 FILEDESC_XUNLOCK(fdp);
752 (void) closef(delfp, td);
753 if (holdleaders) {
754 FILEDESC_XLOCK(fdp);
755 fdp->fd_holdleaderscount--;
756 if (fdp->fd_holdleaderscount == 0 &&
757 fdp->fd_holdleaderswakeup != 0) {
758 fdp->fd_holdleaderswakeup = 0;
759 wakeup(&fdp->fd_holdleaderscount);
760 }
761 FILEDESC_XUNLOCK(fdp);
762 }
763 } else {
764 FILEDESC_XUNLOCK(fdp);
765 }
766 return (0);
767}
768
769/*
770 * If sigio is on the list associated with a process or process group,
771 * disable signalling from the device, remove sigio from the list and
772 * free sigio.
773 */
774void
775funsetown(struct sigio **sigiop)
776{
777 struct sigio *sigio;
778
779 SIGIO_LOCK();
780 sigio = *sigiop;
781 if (sigio == NULL) {
782 SIGIO_UNLOCK();
783 return;
784 }
785 *(sigio->sio_myref) = NULL;
786 if ((sigio)->sio_pgid < 0) {
787 struct pgrp *pg = (sigio)->sio_pgrp;
788 PGRP_LOCK(pg);
789 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
790 sigio, sio_pgsigio);
791 PGRP_UNLOCK(pg);
792 } else {
793 struct proc *p = (sigio)->sio_proc;
794 PROC_LOCK(p);
795 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
796 sigio, sio_pgsigio);
797 PROC_UNLOCK(p);
798 }
799 SIGIO_UNLOCK();
800 crfree(sigio->sio_ucred);
801 FREE(sigio, M_SIGIO);
802}
803
804/*
805 * Free a list of sigio structures.
806 * We only need to lock the SIGIO_LOCK because we have made ourselves
807 * inaccessible to callers of fsetown and therefore do not need to lock
808 * the proc or pgrp struct for the list manipulation.
809 */
810void
811funsetownlst(struct sigiolst *sigiolst)
812{
813 struct proc *p;
814 struct pgrp *pg;
815 struct sigio *sigio;
816
817 sigio = SLIST_FIRST(sigiolst);
818 if (sigio == NULL)
819 return;
820 p = NULL;
821 pg = NULL;
822
823 /*
824 * Every entry of the list should belong
825 * to a single proc or pgrp.
826 */
827 if (sigio->sio_pgid < 0) {
828 pg = sigio->sio_pgrp;
829 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED);
830 } else /* if (sigio->sio_pgid > 0) */ {
831 p = sigio->sio_proc;
832 PROC_LOCK_ASSERT(p, MA_NOTOWNED);
833 }
834
835 SIGIO_LOCK();
836 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) {
837 *(sigio->sio_myref) = NULL;
838 if (pg != NULL) {
839 KASSERT(sigio->sio_pgid < 0,
840 ("Proc sigio in pgrp sigio list"));
841 KASSERT(sigio->sio_pgrp == pg,
842 ("Bogus pgrp in sigio list"));
843 PGRP_LOCK(pg);
844 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio,
845 sio_pgsigio);
846 PGRP_UNLOCK(pg);
847 } else /* if (p != NULL) */ {
848 KASSERT(sigio->sio_pgid > 0,
849 ("Pgrp sigio in proc sigio list"));
850 KASSERT(sigio->sio_proc == p,
851 ("Bogus proc in sigio list"));
852 PROC_LOCK(p);
853 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio,
854 sio_pgsigio);
855 PROC_UNLOCK(p);
856 }
857 SIGIO_UNLOCK();
858 crfree(sigio->sio_ucred);
859 FREE(sigio, M_SIGIO);
860 SIGIO_LOCK();
861 }
862 SIGIO_UNLOCK();
863}
864
865/*
866 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg).
867 *
868 * After permission checking, add a sigio structure to the sigio list for
869 * the process or process group.
870 */
871int
872fsetown(pid_t pgid, struct sigio **sigiop)
873{
874 struct proc *proc;
875 struct pgrp *pgrp;
876 struct sigio *sigio;
877 int ret;
878
879 if (pgid == 0) {
880 funsetown(sigiop);
881 return (0);
882 }
883
884 ret = 0;
885
886 /* Allocate and fill in the new sigio out of locks. */
887 MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK);
888 sigio->sio_pgid = pgid;
889 sigio->sio_ucred = crhold(curthread->td_ucred);
890 sigio->sio_myref = sigiop;
891
892 sx_slock(&proctree_lock);
893 if (pgid > 0) {
894 proc = pfind(pgid);
895 if (proc == NULL) {
896 ret = ESRCH;
897 goto fail;
898 }
899
900 /*
901 * Policy - Don't allow a process to FSETOWN a process
902 * in another session.
903 *
904 * Remove this test to allow maximum flexibility or
905 * restrict FSETOWN to the current process or process
906 * group for maximum safety.
907 */
908 PROC_UNLOCK(proc);
909 if (proc->p_session != curthread->td_proc->p_session) {
910 ret = EPERM;
911 goto fail;
912 }
913
914 pgrp = NULL;
915 } else /* if (pgid < 0) */ {
916 pgrp = pgfind(-pgid);
917 if (pgrp == NULL) {
918 ret = ESRCH;
919 goto fail;
920 }
921 PGRP_UNLOCK(pgrp);
922
923 /*
924 * Policy - Don't allow a process to FSETOWN a process
925 * in another session.
926 *
927 * Remove this test to allow maximum flexibility or
928 * restrict FSETOWN to the current process or process
929 * group for maximum safety.
930 */
931 if (pgrp->pg_session != curthread->td_proc->p_session) {
932 ret = EPERM;
933 goto fail;
934 }
935
936 proc = NULL;
937 }
938 funsetown(sigiop);
939 if (pgid > 0) {
940 PROC_LOCK(proc);
941 /*
942 * Since funsetownlst() is called without the proctree
943 * locked, we need to check for P_WEXIT.
944 * XXX: is ESRCH correct?
945 */
946 if ((proc->p_flag & P_WEXIT) != 0) {
947 PROC_UNLOCK(proc);
948 ret = ESRCH;
949 goto fail;
950 }
951 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
952 sigio->sio_proc = proc;
953 PROC_UNLOCK(proc);
954 } else {
955 PGRP_LOCK(pgrp);
956 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
957 sigio->sio_pgrp = pgrp;
958 PGRP_UNLOCK(pgrp);
959 }
960 sx_sunlock(&proctree_lock);
961 SIGIO_LOCK();
962 *sigiop = sigio;
963 SIGIO_UNLOCK();
964 return (0);
965
966fail:
967 sx_sunlock(&proctree_lock);
968 crfree(sigio->sio_ucred);
969 FREE(sigio, M_SIGIO);
970 return (ret);
971}
972
973/*
974 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
975 */
976pid_t
977fgetown(sigiop)
978 struct sigio **sigiop;
979{
980 pid_t pgid;
981
982 SIGIO_LOCK();
983 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0;
984 SIGIO_UNLOCK();
985 return (pgid);
986}
987
988/*
989 * Close a file descriptor.
990 */
991#ifndef _SYS_SYSPROTO_H_
992struct close_args {
993 int fd;
994};
995#endif
996/* ARGSUSED */
997int
998close(td, uap)
999 struct thread *td;
1000 struct close_args *uap;
1001{
1002
1003 return (kern_close(td, uap->fd));
1004}
1005
1006int
1007kern_close(td, fd)
1008 struct thread *td;
1009 int fd;
1010{
1011 struct filedesc *fdp;
1012 struct file *fp;
1013 int error;
1014 int holdleaders;
1015
1016 error = 0;
1017 holdleaders = 0;
1018 fdp = td->td_proc->p_fd;
1019
1020 AUDIT_SYSCLOSE(td, fd);
1021
1022 FILEDESC_XLOCK(fdp);
1023 if ((unsigned)fd >= fdp->fd_nfiles ||
1024 (fp = fdp->fd_ofiles[fd]) == NULL) {
1025 FILEDESC_XUNLOCK(fdp);
1026 return (EBADF);
1027 }
1028 fdp->fd_ofiles[fd] = NULL;
1029 fdp->fd_ofileflags[fd] = 0;
1030 fdunused(fdp, fd);
1031 if (td->td_proc->p_fdtol != NULL) {
1032 /*
1033 * Ask fdfree() to sleep to ensure that all relevant
1034 * process leaders can be traversed in closef().
1035 */
1036 fdp->fd_holdleaderscount++;
1037 holdleaders = 1;
1038 }
1039
1040 /*
1041 * We now hold the fp reference that used to be owned by the
1042 * descriptor array. We have to unlock the FILEDESC *AFTER*
1043 * knote_fdclose to prevent a race of the fd getting opened, a knote
1044 * added, and deleteing a knote for the new fd.
1045 */
1046 knote_fdclose(td, fd);
1047 if (fp->f_type == DTYPE_MQUEUE)
1048 mq_fdclose(td, fd, fp);
1049 FILEDESC_XUNLOCK(fdp);
1050
1051 error = closef(fp, td);
1052 if (holdleaders) {
1053 FILEDESC_XLOCK(fdp);
1054 fdp->fd_holdleaderscount--;
1055 if (fdp->fd_holdleaderscount == 0 &&
1056 fdp->fd_holdleaderswakeup != 0) {
1057 fdp->fd_holdleaderswakeup = 0;
1058 wakeup(&fdp->fd_holdleaderscount);
1059 }
1060 FILEDESC_XUNLOCK(fdp);
1061 }
1062 return (error);
1063}
1064
1065#if defined(COMPAT_43)
1066/*
1067 * Return status information about a file descriptor.
1068 */
1069#ifndef _SYS_SYSPROTO_H_
1070struct ofstat_args {
1071 int fd;
1072 struct ostat *sb;
1073};
1074#endif
1075/* ARGSUSED */
1076int
1077ofstat(struct thread *td, struct ofstat_args *uap)
1078{
1079 struct ostat oub;
1080 struct stat ub;
1081 int error;
1082
1083 error = kern_fstat(td, uap->fd, &ub);
1084 if (error == 0) {
1085 cvtstat(&ub, &oub);
1086 error = copyout(&oub, uap->sb, sizeof(oub));
1087 }
1088 return (error);
1089}
1090#endif /* COMPAT_43 */
1091
1092/*
1093 * Return status information about a file descriptor.
1094 */
1095#ifndef _SYS_SYSPROTO_H_
1096struct fstat_args {
1097 int fd;
1098 struct stat *sb;
1099};
1100#endif
1101/* ARGSUSED */
1102int
1103fstat(struct thread *td, struct fstat_args *uap)
1104{
1105 struct stat ub;
1106 int error;
1107
1108 error = kern_fstat(td, uap->fd, &ub);
1109 if (error == 0)
1110 error = copyout(&ub, uap->sb, sizeof(ub));
1111 return (error);
1112}
1113
1114int
1115kern_fstat(struct thread *td, int fd, struct stat *sbp)
1116{
1117 struct file *fp;
1118 int error;
1119
1120 AUDIT_ARG(fd, fd);
1121
1122 if ((error = fget(td, fd, &fp)) != 0)
1123 return (error);
1124
1125 AUDIT_ARG(file, td->td_proc, fp);
1126
1127 error = fo_stat(fp, sbp, td->td_ucred, td);
1128 fdrop(fp, td);
1129 return (error);
1130}
1131
1132/*
1133 * Return status information about a file descriptor.
1134 */
1135#ifndef _SYS_SYSPROTO_H_
1136struct nfstat_args {
1137 int fd;
1138 struct nstat *sb;
1139};
1140#endif
1141/* ARGSUSED */
1142int
1143nfstat(struct thread *td, struct nfstat_args *uap)
1144{
1145 struct nstat nub;
1146 struct stat ub;
1147 int error;
1148
1149 error = kern_fstat(td, uap->fd, &ub);
1150 if (error == 0) {
1151 cvtnstat(&ub, &nub);
1152 error = copyout(&nub, uap->sb, sizeof(nub));
1153 }
1154 return (error);
1155}
1156
1157/*
1158 * Return pathconf information about a file descriptor.
1159 */
1160#ifndef _SYS_SYSPROTO_H_
1161struct fpathconf_args {
1162 int fd;
1163 int name;
1164};
1165#endif
1166/* ARGSUSED */
1167int
1168fpathconf(struct thread *td, struct fpathconf_args *uap)
1169{
1170 struct file *fp;
1171 struct vnode *vp;
1172 int error;
1173
1174 if ((error = fget(td, uap->fd, &fp)) != 0)
1175 return (error);
1176
1177 /* If asynchronous I/O is available, it works for all descriptors. */
1178 if (uap->name == _PC_ASYNC_IO) {
1179 td->td_retval[0] = async_io_version;
1180 goto out;
1181 }
1182 vp = fp->f_vnode;
1183 if (vp != NULL) {
1184 int vfslocked;
1185 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
1186 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
1187 error = VOP_PATHCONF(vp, uap->name, td->td_retval);
1188 VOP_UNLOCK(vp, 0, td);
1189 VFS_UNLOCK_GIANT(vfslocked);
1190 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) {
1191 if (uap->name != _PC_PIPE_BUF) {
1192 error = EINVAL;
1193 } else {
1194 td->td_retval[0] = PIPE_BUF;
1195 error = 0;
1196 }
1197 } else {
1198 error = EOPNOTSUPP;
1199 }
1200out:
1201 fdrop(fp, td);
1202 return (error);
1203}
1204
1205/*
1206 * Grow the file table to accomodate (at least) nfd descriptors. This may
1207 * block and drop the filedesc lock, but it will reacquire it before
1208 * returning.
1209 */
1210static void
1211fdgrowtable(struct filedesc *fdp, int nfd)
1212{
1213 struct file **ntable;
1214 char *nfileflags;
1215 int nnfiles, onfiles;
1216 NDSLOTTYPE *nmap;
1217
1218 FILEDESC_XLOCK_ASSERT(fdp);
1219
1220 KASSERT(fdp->fd_nfiles > 0,
1221 ("zero-length file table"));
1222
1223 /* compute the size of the new table */
1224 onfiles = fdp->fd_nfiles;
1225 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */
1226 if (nnfiles <= onfiles)
1227 /* the table is already large enough */
1228 return;
1229
1230 /* allocate a new table and (if required) new bitmaps */
1231 FILEDESC_XUNLOCK(fdp);
1232 MALLOC(ntable, struct file **, nnfiles * OFILESIZE,
1233 M_FILEDESC, M_ZERO | M_WAITOK);
1234 nfileflags = (char *)&ntable[nnfiles];
1235 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles))
1236 MALLOC(nmap, NDSLOTTYPE *, NDSLOTS(nnfiles) * NDSLOTSIZE,
1237 M_FILEDESC, M_ZERO | M_WAITOK);
1238 else
1239 nmap = NULL;
1240 FILEDESC_XLOCK(fdp);
1241
1242 /*
1243 * We now have new tables ready to go. Since we dropped the
1244 * filedesc lock to call malloc(), watch out for a race.
1245 */
1246 onfiles = fdp->fd_nfiles;
1247 if (onfiles >= nnfiles) {
1248 /* we lost the race, but that's OK */
1249 free(ntable, M_FILEDESC);
1250 if (nmap != NULL)
1251 free(nmap, M_FILEDESC);
1252 return;
1253 }
1254 bcopy(fdp->fd_ofiles, ntable, onfiles * sizeof(*ntable));
1255 bcopy(fdp->fd_ofileflags, nfileflags, onfiles);
1256 if (onfiles > NDFILE)
1257 free(fdp->fd_ofiles, M_FILEDESC);
1258 fdp->fd_ofiles = ntable;
1259 fdp->fd_ofileflags = nfileflags;
1260 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) {
1261 bcopy(fdp->fd_map, nmap, NDSLOTS(onfiles) * sizeof(*nmap));
1262 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE))
1263 free(fdp->fd_map, M_FILEDESC);
1264 fdp->fd_map = nmap;
1265 }
1266 fdp->fd_nfiles = nnfiles;
1267}
1268
1269/*
1270 * Allocate a file descriptor for the process.
1271 */
1272int
1273fdalloc(struct thread *td, int minfd, int *result)
1274{
1275 struct proc *p = td->td_proc;
1276 struct filedesc *fdp = p->p_fd;
1277 int fd = -1, maxfd;
1278
1279 FILEDESC_XLOCK_ASSERT(fdp);
1280
1281 if (fdp->fd_freefile > minfd)
1282 minfd = fdp->fd_freefile;
1283
1284 PROC_LOCK(p);
1285 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
1286 PROC_UNLOCK(p);
1287
1288 /*
1289 * Search the bitmap for a free descriptor. If none is found, try
1290 * to grow the file table. Keep at it until we either get a file
1291 * descriptor or run into process or system limits; fdgrowtable()
1292 * may drop the filedesc lock, so we're in a race.
1293 */
1294 for (;;) {
1295 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles);
1296 if (fd >= maxfd)
1297 return (EMFILE);
1298 if (fd < fdp->fd_nfiles)
1299 break;
1300 fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd));
1301 }
1302
1303 /*
1304 * Perform some sanity checks, then mark the file descriptor as
1305 * used and return it to the caller.
1306 */
1307 KASSERT(!fdisused(fdp, fd),
1308 ("fd_first_free() returned non-free descriptor"));
1309 KASSERT(fdp->fd_ofiles[fd] == NULL,
1310 ("free descriptor isn't"));
1311 fdp->fd_ofileflags[fd] = 0; /* XXX needed? */
1312 fdused(fdp, fd);
1313 *result = fd;
1314 return (0);
1315}
1316
1317/*
1318 * Check to see whether n user file descriptors are available to the process
1319 * p.
1320 */
1321int
1322fdavail(struct thread *td, int n)
1323{
1324 struct proc *p = td->td_proc;
1325 struct filedesc *fdp = td->td_proc->p_fd;
1326 struct file **fpp;
1327 int i, lim, last;
1328
1329 FILEDESC_LOCK_ASSERT(fdp);
1330
1331 PROC_LOCK(p);
1332 lim = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
1333 PROC_UNLOCK(p);
1334 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
1335 return (1);
1336 last = min(fdp->fd_nfiles, lim);
1337 fpp = &fdp->fd_ofiles[fdp->fd_freefile];
1338 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) {
1339 if (*fpp == NULL && --n <= 0)
1340 return (1);
1341 }
1342 return (0);
1343}
1344
1345/*
1346 * Create a new open file structure and allocate a file decriptor for the
1347 * process that refers to it. We add one reference to the file for the
1348 * descriptor table and one reference for resultfp. This is to prevent us
1349 * being preempted and the entry in the descriptor table closed after we
1350 * release the FILEDESC lock.
1351 */
1352int
1353falloc(struct thread *td, struct file **resultfp, int *resultfd)
1354{
1355 struct proc *p = td->td_proc;
1356 struct file *fp;
1357 int error, i;
1358 int maxuserfiles = maxfiles - (maxfiles / 20);
1359 static struct timeval lastfail;
1360 static int curfail;
1361
1362 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO);
1363 if ((openfiles >= maxuserfiles &&
1364 priv_check(td, PRIV_MAXFILES) != 0) ||
1365 openfiles >= maxfiles) {
1366 if (ppsratecheck(&lastfail, &curfail, 1)) {
1367 printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n",
1368 td->td_ucred->cr_ruid);
1369 }
1370 uma_zfree(file_zone, fp);
1371 return (ENFILE);
1372 }
1373 atomic_add_int(&openfiles, 1);
1374
1375 /*
1376 * If the process has file descriptor zero open, add the new file
1377 * descriptor to the list of open files at that point, otherwise
1378 * put it at the front of the list of open files.
1379 */
1380 fp->f_count = 1;
1381 if (resultfp)
1382 fp->f_count++;
1383 fp->f_cred = crhold(td->td_ucred);
1384 fp->f_ops = &badfileops;
1385 fp->f_data = NULL;
1386 fp->f_vnode = NULL;
1387 FILEDESC_XLOCK(p->p_fd);
1388 if ((error = fdalloc(td, 0, &i))) {
1389 FILEDESC_XUNLOCK(p->p_fd);
1390 fdrop(fp, td);
1391 if (resultfp)
1392 fdrop(fp, td);
1393 return (error);
1394 }
1395 p->p_fd->fd_ofiles[i] = fp;
1396 FILEDESC_XUNLOCK(p->p_fd);
1397 if (resultfp)
1398 *resultfp = fp;
1399 if (resultfd)
1400 *resultfd = i;
1401 return (0);
1402}
1403
1404/*
1405 * Build a new filedesc structure from another.
1406 * Copy the current, root, and jail root vnode references.
1407 */
1408struct filedesc *
1409fdinit(struct filedesc *fdp)
1410{
1411 struct filedesc0 *newfdp;
1412
1413 newfdp = malloc(sizeof *newfdp, M_FILEDESC, M_WAITOK | M_ZERO);
1414 FILEDESC_LOCK_INIT(&newfdp->fd_fd);
1415 if (fdp != NULL) {
1416 FILEDESC_XLOCK(fdp);
1417 newfdp->fd_fd.fd_cdir = fdp->fd_cdir;
1418 if (newfdp->fd_fd.fd_cdir)
1419 VREF(newfdp->fd_fd.fd_cdir);
1420 newfdp->fd_fd.fd_rdir = fdp->fd_rdir;
1421 if (newfdp->fd_fd.fd_rdir)
1422 VREF(newfdp->fd_fd.fd_rdir);
1423 newfdp->fd_fd.fd_jdir = fdp->fd_jdir;
1424 if (newfdp->fd_fd.fd_jdir)
1425 VREF(newfdp->fd_fd.fd_jdir);
1426 FILEDESC_XUNLOCK(fdp);
1427 }
1428
1429 /* Create the file descriptor table. */
1430 newfdp->fd_fd.fd_refcnt = 1;
1431 newfdp->fd_fd.fd_holdcnt = 1;
1432 newfdp->fd_fd.fd_cmask = CMASK;
1433 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles;
1434 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags;
1435 newfdp->fd_fd.fd_nfiles = NDFILE;
1436 newfdp->fd_fd.fd_map = newfdp->fd_dmap;
1437 newfdp->fd_fd.fd_lastfile = -1;
1438 return (&newfdp->fd_fd);
1439}
1440
1441static struct filedesc *
1442fdhold(struct proc *p)
1443{
1444 struct filedesc *fdp;
1445
1446 mtx_lock(&fdesc_mtx);
1447 fdp = p->p_fd;
1448 if (fdp != NULL)
1449 fdp->fd_holdcnt++;
1450 mtx_unlock(&fdesc_mtx);
1451 return (fdp);
1452}
1453
1454static void
1455fddrop(struct filedesc *fdp)
1456{
1457 int i;
1458
1459 mtx_lock(&fdesc_mtx);
1460 i = --fdp->fd_holdcnt;
1461 mtx_unlock(&fdesc_mtx);
1462 if (i > 0)
1463 return;
1464
1465 FILEDESC_LOCK_DESTROY(fdp);
1466 FREE(fdp, M_FILEDESC);
1467}
1468
1469/*
1470 * Share a filedesc structure.
1471 */
1472struct filedesc *
1473fdshare(struct filedesc *fdp)
1474{
1475
1476 FILEDESC_XLOCK(fdp);
1477 fdp->fd_refcnt++;
1478 FILEDESC_XUNLOCK(fdp);
1479 return (fdp);
1480}
1481
1482/*
1483 * Unshare a filedesc structure, if necessary by making a copy
1484 */
1485void
1486fdunshare(struct proc *p, struct thread *td)
1487{
1488
1489 FILEDESC_XLOCK(p->p_fd);
1490 if (p->p_fd->fd_refcnt > 1) {
1491 struct filedesc *tmp;
1492
1493 FILEDESC_XUNLOCK(p->p_fd);
1494 tmp = fdcopy(p->p_fd);
1495 fdfree(td);
1496 p->p_fd = tmp;
1497 } else
1498 FILEDESC_XUNLOCK(p->p_fd);
1499}
1500
1501/*
1502 * Copy a filedesc structure. A NULL pointer in returns a NULL reference,
1503 * this is to ease callers, not catch errors.
1504 */
1505struct filedesc *
1506fdcopy(struct filedesc *fdp)
1507{
1508 struct filedesc *newfdp;
1509 int i;
1510
1511 /* Certain daemons might not have file descriptors. */
1512 if (fdp == NULL)
1513 return (NULL);
1514
1515 newfdp = fdinit(fdp);
1516 FILEDESC_SLOCK(fdp);
1517 while (fdp->fd_lastfile >= newfdp->fd_nfiles) {
1518 FILEDESC_SUNLOCK(fdp);
1519 FILEDESC_XLOCK(newfdp);
1520 fdgrowtable(newfdp, fdp->fd_lastfile + 1);
1521 FILEDESC_XUNLOCK(newfdp);
1522 FILEDESC_SLOCK(fdp);
1523 }
1524 /* copy everything except kqueue descriptors */
1525 newfdp->fd_freefile = -1;
1526 for (i = 0; i <= fdp->fd_lastfile; ++i) {
1527 if (fdisused(fdp, i) &&
1528 fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE) {
1529 newfdp->fd_ofiles[i] = fdp->fd_ofiles[i];
1530 newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i];
1531 fhold(newfdp->fd_ofiles[i]);
1532 newfdp->fd_lastfile = i;
1533 } else {
1534 if (newfdp->fd_freefile == -1)
1535 newfdp->fd_freefile = i;
1536 }
1537 }
1538 FILEDESC_SUNLOCK(fdp);
1539 FILEDESC_XLOCK(newfdp);
1540 for (i = 0; i <= newfdp->fd_lastfile; ++i)
1541 if (newfdp->fd_ofiles[i] != NULL)
1542 fdused(newfdp, i);
1543 FILEDESC_XUNLOCK(newfdp);
1544 FILEDESC_SLOCK(fdp);
1545 if (newfdp->fd_freefile == -1)
1546 newfdp->fd_freefile = i;
1547 newfdp->fd_cmask = fdp->fd_cmask;
1548 FILEDESC_SUNLOCK(fdp);
1549 return (newfdp);
1550}
1551
1552/*
1553 * Release a filedesc structure.
1554 */
1555void
1556fdfree(struct thread *td)
1557{
1558 struct filedesc *fdp;
1559 struct file **fpp;
1560 int i, locked;
1561 struct filedesc_to_leader *fdtol;
1562 struct file *fp;
1563 struct vnode *cdir, *jdir, *rdir, *vp;
1564 struct flock lf;
1565
1566 /* Certain daemons might not have file descriptors. */
1567 fdp = td->td_proc->p_fd;
1568 if (fdp == NULL)
1569 return;
1570
1571 /* Check for special need to clear POSIX style locks */
1572 fdtol = td->td_proc->p_fdtol;
1573 if (fdtol != NULL) {
1574 FILEDESC_XLOCK(fdp);
1575 KASSERT(fdtol->fdl_refcount > 0,
1576 ("filedesc_to_refcount botch: fdl_refcount=%d",
1577 fdtol->fdl_refcount));
1578 if (fdtol->fdl_refcount == 1 &&
1579 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
1580 for (i = 0, fpp = fdp->fd_ofiles;
1581 i <= fdp->fd_lastfile;
1582 i++, fpp++) {
1583 if (*fpp == NULL ||
1584 (*fpp)->f_type != DTYPE_VNODE)
1585 continue;
1586 fp = *fpp;
1587 fhold(fp);
1588 FILEDESC_XUNLOCK(fdp);
1589 lf.l_whence = SEEK_SET;
1590 lf.l_start = 0;
1591 lf.l_len = 0;
1592 lf.l_type = F_UNLCK;
1593 vp = fp->f_vnode;
1594 locked = VFS_LOCK_GIANT(vp->v_mount);
1595 (void) VOP_ADVLOCK(vp,
1596 (caddr_t)td->td_proc->
1597 p_leader,
1598 F_UNLCK,
1599 &lf,
1600 F_POSIX);
1601 VFS_UNLOCK_GIANT(locked);
1602 FILEDESC_XLOCK(fdp);
1603 fdrop(fp, td);
1604 fpp = fdp->fd_ofiles + i;
1605 }
1606 }
1607 retry:
1608 if (fdtol->fdl_refcount == 1) {
1609 if (fdp->fd_holdleaderscount > 0 &&
1610 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
1611 /*
1612 * close() or do_dup() has cleared a reference
1613 * in a shared file descriptor table.
1614 */
1615 fdp->fd_holdleaderswakeup = 1;
1616 sx_sleep(&fdp->fd_holdleaderscount,
1617 FILEDESC_LOCK(fdp), PLOCK, "fdlhold", 0);
1618 goto retry;
1619 }
1620 if (fdtol->fdl_holdcount > 0) {
1621 /*
1622 * Ensure that fdtol->fdl_leader remains
1623 * valid in closef().
1624 */
1625 fdtol->fdl_wakeup = 1;
1626 sx_sleep(fdtol, FILEDESC_LOCK(fdp), PLOCK,
1627 "fdlhold", 0);
1628 goto retry;
1629 }
1630 }
1631 fdtol->fdl_refcount--;
1632 if (fdtol->fdl_refcount == 0 &&
1633 fdtol->fdl_holdcount == 0) {
1634 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev;
1635 fdtol->fdl_prev->fdl_next = fdtol->fdl_next;
1636 } else
1637 fdtol = NULL;
1638 td->td_proc->p_fdtol = NULL;
1639 FILEDESC_XUNLOCK(fdp);
1640 if (fdtol != NULL)
1641 FREE(fdtol, M_FILEDESC_TO_LEADER);
1642 }
1643 FILEDESC_XLOCK(fdp);
1644 i = --fdp->fd_refcnt;
1645 FILEDESC_XUNLOCK(fdp);
1646 if (i > 0)
1647 return;
1648 /*
1649 * We are the last reference to the structure, so we can
1650 * safely assume it will not change out from under us.
1651 */
1652 fpp = fdp->fd_ofiles;
1653 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) {
1654 if (*fpp)
1655 (void) closef(*fpp, td);
1656 }
1657 FILEDESC_XLOCK(fdp);
1658
1659 /* XXX This should happen earlier. */
1660 mtx_lock(&fdesc_mtx);
1661 td->td_proc->p_fd = NULL;
1662 mtx_unlock(&fdesc_mtx);
1663
1664 if (fdp->fd_nfiles > NDFILE)
1665 FREE(fdp->fd_ofiles, M_FILEDESC);
1666 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE))
1667 FREE(fdp->fd_map, M_FILEDESC);
1668
1669 fdp->fd_nfiles = 0;
1670
1671 cdir = fdp->fd_cdir;
1672 fdp->fd_cdir = NULL;
1673 rdir = fdp->fd_rdir;
1674 fdp->fd_rdir = NULL;
1675 jdir = fdp->fd_jdir;
1676 fdp->fd_jdir = NULL;
1677 FILEDESC_XUNLOCK(fdp);
1678
1679 if (cdir) {
1680 locked = VFS_LOCK_GIANT(cdir->v_mount);
1681 vrele(cdir);
1682 VFS_UNLOCK_GIANT(locked);
1683 }
1684 if (rdir) {
1685 locked = VFS_LOCK_GIANT(rdir->v_mount);
1686 vrele(rdir);
1687 VFS_UNLOCK_GIANT(locked);
1688 }
1689 if (jdir) {
1690 locked = VFS_LOCK_GIANT(jdir->v_mount);
1691 vrele(jdir);
1692 VFS_UNLOCK_GIANT(locked);
1693 }
1694
1695 fddrop(fdp);
1696}
1697
1698/*
1699 * For setugid programs, we don't want to people to use that setugidness
1700 * to generate error messages which write to a file which otherwise would
1701 * otherwise be off-limits to the process. We check for filesystems where
1702 * the vnode can change out from under us after execve (like [lin]procfs).
1703 *
1704 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is
1705 * sufficient. We also don't check for setugidness since we know we are.
1706 */
1707static int
1708is_unsafe(struct file *fp)
1709{
1710 if (fp->f_type == DTYPE_VNODE) {
1711 struct vnode *vp = fp->f_vnode;
1712
1713 if ((vp->v_vflag & VV_PROCDEP) != 0)
1714 return (1);
1715 }
1716 return (0);
1717}
1718
1719/*
1720 * Make this setguid thing safe, if at all possible.
1721 */
1722void
1723setugidsafety(struct thread *td)
1724{
1725 struct filedesc *fdp;
1726 int i;
1727
1728 /* Certain daemons might not have file descriptors. */
1729 fdp = td->td_proc->p_fd;
1730 if (fdp == NULL)
1731 return;
1732
1733 /*
1734 * Note: fdp->fd_ofiles may be reallocated out from under us while
1735 * we are blocked in a close. Be careful!
1736 */
1737 FILEDESC_XLOCK(fdp);
1738 for (i = 0; i <= fdp->fd_lastfile; i++) {
1739 if (i > 2)
1740 break;
1741 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) {
1742 struct file *fp;
1743
1744 knote_fdclose(td, i);
1745 /*
1746 * NULL-out descriptor prior to close to avoid
1747 * a race while close blocks.
1748 */
1749 fp = fdp->fd_ofiles[i];
1750 fdp->fd_ofiles[i] = NULL;
1751 fdp->fd_ofileflags[i] = 0;
1752 fdunused(fdp, i);
1753 FILEDESC_XUNLOCK(fdp);
1754 (void) closef(fp, td);
1755 FILEDESC_XLOCK(fdp);
1756 }
1757 }
1758 FILEDESC_XUNLOCK(fdp);
1759}
1760
1761/*
1762 * If a specific file object occupies a specific file descriptor, close the
1763 * file descriptor entry and drop a reference on the file object. This is a
1764 * convenience function to handle a subsequent error in a function that calls
1765 * falloc() that handles the race that another thread might have closed the
1766 * file descriptor out from under the thread creating the file object.
1767 */
1768void
1769fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td)
1770{
1771
1772 FILEDESC_XLOCK(fdp);
1773 if (fdp->fd_ofiles[idx] == fp) {
1774 fdp->fd_ofiles[idx] = NULL;
1775 fdunused(fdp, idx);
1776 FILEDESC_XUNLOCK(fdp);
1777 fdrop(fp, td);
1778 } else
1779 FILEDESC_XUNLOCK(fdp);
1780}
1781
1782/*
1783 * Close any files on exec?
1784 */
1785void
1786fdcloseexec(struct thread *td)
1787{
1788 struct filedesc *fdp;
1789 int i;
1790
1791 /* Certain daemons might not have file descriptors. */
1792 fdp = td->td_proc->p_fd;
1793 if (fdp == NULL)
1794 return;
1795
1796 FILEDESC_XLOCK(fdp);
1797
1798 /*
1799 * We cannot cache fd_ofiles or fd_ofileflags since operations
1800 * may block and rip them out from under us.
1801 */
1802 for (i = 0; i <= fdp->fd_lastfile; i++) {
1803 if (fdp->fd_ofiles[i] != NULL &&
1804 (fdp->fd_ofiles[i]->f_type == DTYPE_MQUEUE ||
1805 (fdp->fd_ofileflags[i] & UF_EXCLOSE))) {
1806 struct file *fp;
1807
1808 knote_fdclose(td, i);
1809 /*
1810 * NULL-out descriptor prior to close to avoid
1811 * a race while close blocks.
1812 */
1813 fp = fdp->fd_ofiles[i];
1814 fdp->fd_ofiles[i] = NULL;
1815 fdp->fd_ofileflags[i] = 0;
1816 fdunused(fdp, i);
1817 if (fp->f_type == DTYPE_MQUEUE)
1818 mq_fdclose(td, i, fp);
1819 FILEDESC_XUNLOCK(fdp);
1820 (void) closef(fp, td);
1821 FILEDESC_XLOCK(fdp);
1822 }
1823 }
1824 FILEDESC_XUNLOCK(fdp);
1825}
1826
1827/*
1828 * It is unsafe for set[ug]id processes to be started with file
1829 * descriptors 0..2 closed, as these descriptors are given implicit
1830 * significance in the Standard C library. fdcheckstd() will create a
1831 * descriptor referencing /dev/null for each of stdin, stdout, and
1832 * stderr that is not already open.
1833 */
1834int
1835fdcheckstd(struct thread *td)
1836{
1837 struct filedesc *fdp;
1838 register_t retval, save;
1839 int i, error, devnull;
1840
1841 fdp = td->td_proc->p_fd;
1842 if (fdp == NULL)
1843 return (0);
1844 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared"));
1845 devnull = -1;
1846 error = 0;
1847 for (i = 0; i < 3; i++) {
1848 if (fdp->fd_ofiles[i] != NULL)
1849 continue;
1850 if (devnull < 0) {
1851 save = td->td_retval[0];
1852 error = kern_open(td, "/dev/null", UIO_SYSSPACE,
1853 O_RDWR, 0);
1854 devnull = td->td_retval[0];
1855 KASSERT(devnull == i, ("oof, we didn't get our fd"));
1856 td->td_retval[0] = save;
1857 if (error)
1858 break;
1859 } else {
1860 error = do_dup(td, DUP_FIXED, devnull, i, &retval);
1861 if (error != 0)
1862 break;
1863 }
1864 }
1865 return (error);
1866}
1867
1868/*
1869 * Internal form of close. Decrement reference count on file structure.
1870 * Note: td may be NULL when closing a file that was being passed in a
1871 * message.
1872 *
1873 * XXXRW: Giant is not required for the caller, but often will be held; this
1874 * makes it moderately likely the Giant will be recursed in the VFS case.
1875 */
1876int
1877closef(struct file *fp, struct thread *td)
1878{
1879 struct vnode *vp;
1880 struct flock lf;
1881 struct filedesc_to_leader *fdtol;
1882 struct filedesc *fdp;
1883
1884 /*
1885 * POSIX record locking dictates that any close releases ALL
1886 * locks owned by this process. This is handled by setting
1887 * a flag in the unlock to free ONLY locks obeying POSIX
1888 * semantics, and not to free BSD-style file locks.
1889 * If the descriptor was in a message, POSIX-style locks
1890 * aren't passed with the descriptor, and the thread pointer
1891 * will be NULL. Callers should be careful only to pass a
1892 * NULL thread pointer when there really is no owning
1893 * context that might have locks, or the locks will be
1894 * leaked.
1895 */
1896 if (fp->f_type == DTYPE_VNODE && td != NULL) {
1897 int vfslocked;
1898
1899 vp = fp->f_vnode;
1900 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
1901 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
1902 lf.l_whence = SEEK_SET;
1903 lf.l_start = 0;
1904 lf.l_len = 0;
1905 lf.l_type = F_UNLCK;
1906 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader,
1907 F_UNLCK, &lf, F_POSIX);
1908 }
1909 fdtol = td->td_proc->p_fdtol;
1910 if (fdtol != NULL) {
1911 /*
1912 * Handle special case where file descriptor table is
1913 * shared between multiple process leaders.
1914 */
1915 fdp = td->td_proc->p_fd;
1916 FILEDESC_XLOCK(fdp);
1917 for (fdtol = fdtol->fdl_next;
1918 fdtol != td->td_proc->p_fdtol;
1919 fdtol = fdtol->fdl_next) {
1920 if ((fdtol->fdl_leader->p_flag &
1921 P_ADVLOCK) == 0)
1922 continue;
1923 fdtol->fdl_holdcount++;
1924 FILEDESC_XUNLOCK(fdp);
1925 lf.l_whence = SEEK_SET;
1926 lf.l_start = 0;
1927 lf.l_len = 0;
1928 lf.l_type = F_UNLCK;
1929 vp = fp->f_vnode;
1930 (void) VOP_ADVLOCK(vp,
1931 (caddr_t)fdtol->fdl_leader,
1932 F_UNLCK, &lf, F_POSIX);
1933 FILEDESC_XLOCK(fdp);
1934 fdtol->fdl_holdcount--;
1935 if (fdtol->fdl_holdcount == 0 &&
1936 fdtol->fdl_wakeup != 0) {
1937 fdtol->fdl_wakeup = 0;
1938 wakeup(fdtol);
1939 }
1940 }
1941 FILEDESC_XUNLOCK(fdp);
1942 }
1943 VFS_UNLOCK_GIANT(vfslocked);
1944 }
1945 return (fdrop(fp, td));
1946}
1947
1948/*
1949 * Initialize the file pointer with the specified properties.
1950 *
1951 * The ops are set with release semantics to be certain that the flags, type,
1952 * and data are visible when ops is. This is to prevent ops methods from being
1953 * called with bad data.
1954 */
1955void
1956finit(struct file *fp, u_int flag, short type, void *data, struct fileops *ops)
1957{
1958 fp->f_data = data;
1959 fp->f_flag = flag;
1960 fp->f_type = type;
1961 atomic_store_rel_ptr((volatile uintptr_t *)&fp->f_ops, (uintptr_t)ops);
1962}
1963
1964
1965/*
1966 * Extract the file pointer associated with the specified descriptor for the
1967 * current user process.
1968 *
1969 * If the descriptor doesn't exist, EBADF is returned.
1970 *
1971 * If the descriptor exists but doesn't match 'flags' then return EBADF for
1972 * read attempts and EINVAL for write attempts.
1973 *
1974 * If 'hold' is set (non-zero) the file's refcount will be bumped on return.
1975 * It should be dropped with fdrop(). If it is not set, then the refcount
1976 * will not be bumped however the thread's filedesc struct will be returned
1977 * locked (for fgetsock).
1978 *
1979 * If an error occured the non-zero error is returned and *fpp is set to
1980 * NULL. Otherwise *fpp is set and zero is returned.
1981 */
1982static __inline int
1983_fget(struct thread *td, int fd, struct file **fpp, int flags, int hold)
1984{
1985 struct filedesc *fdp;
1986 struct file *fp;
1987
1988 *fpp = NULL;
1989 if (td == NULL || (fdp = td->td_proc->p_fd) == NULL)
1990 return (EBADF);
1991 FILEDESC_SLOCK(fdp);
1992 if ((fp = fget_locked(fdp, fd)) == NULL || fp->f_ops == &badfileops) {
1993 FILEDESC_SUNLOCK(fdp);
1994 return (EBADF);
1995 }
1996
1997 /*
1998 * FREAD and FWRITE failure return EBADF as per POSIX.
1999 *
2000 * Only one flag, or 0, may be specified.
2001 */
2002 if (flags == FREAD && (fp->f_flag & FREAD) == 0) {
2003 FILEDESC_SUNLOCK(fdp);
2004 return (EBADF);
2005 }
2006 if (flags == FWRITE && (fp->f_flag & FWRITE) == 0) {
2007 FILEDESC_SUNLOCK(fdp);
2008 return (EBADF);
2009 }
2010 if (hold) {
2011 fhold(fp);
2012 FILEDESC_SUNLOCK(fdp);
2013 }
2014 *fpp = fp;
2015 return (0);
2016}
2017
2018int
2019fget(struct thread *td, int fd, struct file **fpp)
2020{
2021
2022 return(_fget(td, fd, fpp, 0, 1));
2023}
2024
2025int
2026fget_read(struct thread *td, int fd, struct file **fpp)
2027{
2028
2029 return(_fget(td, fd, fpp, FREAD, 1));
2030}
2031
2032int
2033fget_write(struct thread *td, int fd, struct file **fpp)
2034{
2035
2036 return(_fget(td, fd, fpp, FWRITE, 1));
2037}
2038
2039/*
2040 * Like fget() but loads the underlying vnode, or returns an error if the
2041 * descriptor does not represent a vnode. Note that pipes use vnodes but
2042 * never have VM objects. The returned vnode will be vref()'d.
2043 *
2044 * XXX: what about the unused flags ?
2045 */
2046static __inline int
2047_fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags)
2048{
2049 struct file *fp;
2050 int error;
2051
2052 *vpp = NULL;
2053 if ((error = _fget(td, fd, &fp, 0, 0)) != 0)
2054 return (error);
2055 if (fp->f_vnode == NULL) {
2056 error = EINVAL;
2057 } else {
2058 *vpp = fp->f_vnode;
2059 vref(*vpp);
2060 }
2061 FILEDESC_SUNLOCK(td->td_proc->p_fd);
2062 return (error);
2063}
2064
2065int
2066fgetvp(struct thread *td, int fd, struct vnode **vpp)
2067{
2068
2069 return (_fgetvp(td, fd, vpp, 0));
2070}
2071
2072int
2073fgetvp_read(struct thread *td, int fd, struct vnode **vpp)
2074{
2075
2076 return (_fgetvp(td, fd, vpp, FREAD));
2077}
2078
2079#ifdef notyet
2080int
2081fgetvp_write(struct thread *td, int fd, struct vnode **vpp)
2082{
2083
2084 return (_fgetvp(td, fd, vpp, FWRITE));
2085}
2086#endif
2087
2088/*
2089 * Like fget() but loads the underlying socket, or returns an error if the
2090 * descriptor does not represent a socket.
2091 *
2092 * We bump the ref count on the returned socket. XXX Also obtain the SX lock
2093 * in the future.
2094 *
2095 * XXXRW: fgetsock() and fputsock() are deprecated, as consumers should rely
2096 * on their file descriptor reference to prevent the socket from being free'd
2097 * during use.
2098 */
2099int
2100fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp)
2101{
2102 struct file *fp;
2103 int error;
2104
2105 *spp = NULL;
2106 if (fflagp != NULL)
2107 *fflagp = 0;
2108 if ((error = _fget(td, fd, &fp, 0, 0)) != 0)
2109 return (error);
2110 if (fp->f_type != DTYPE_SOCKET) {
2111 error = ENOTSOCK;
2112 } else {
2113 *spp = fp->f_data;
2114 if (fflagp)
2115 *fflagp = fp->f_flag;
2116 SOCK_LOCK(*spp);
2117 soref(*spp);
2118 SOCK_UNLOCK(*spp);
2119 }
2120 FILEDESC_SUNLOCK(td->td_proc->p_fd);
2121 return (error);
2122}
2123
2124/*
2125 * Drop the reference count on the socket and XXX release the SX lock in the
2126 * future. The last reference closes the socket.
2127 *
2128 * XXXRW: fputsock() is deprecated, see comment for fgetsock().
2129 */
2130void
2131fputsock(struct socket *so)
2132{
2133
2134 ACCEPT_LOCK();
2135 SOCK_LOCK(so);
2136 sorele(so);
2137}
2138
2139/*
2140 * Handle the last reference to a file being closed.
2141 */
2142int
2143_fdrop(struct file *fp, struct thread *td)
2144{
2145 int error;
2146
2147 error = 0;
2148 if (fp->f_count != 0)
2149 panic("fdrop: count %d", fp->f_count);
2150 if (fp->f_ops != &badfileops)
2151 error = fo_close(fp, td);
2152 atomic_subtract_int(&openfiles, 1);
2153 crfree(fp->f_cred);
2154 uma_zfree(file_zone, fp);
2155
2156 return (error);
2157}
2158
2159/*
2160 * Apply an advisory lock on a file descriptor.
2161 *
2162 * Just attempt to get a record lock of the requested type on the entire file
2163 * (l_whence = SEEK_SET, l_start = 0, l_len = 0).
2164 */
2165#ifndef _SYS_SYSPROTO_H_
2166struct flock_args {
2167 int fd;
2168 int how;
2169};
2170#endif
2171/* ARGSUSED */
2172int
2173flock(struct thread *td, struct flock_args *uap)
2174{
2175 struct file *fp;
2176 struct vnode *vp;
2177 struct flock lf;
2178 int vfslocked;
2179 int error;
2180
2181 if ((error = fget(td, uap->fd, &fp)) != 0)
2182 return (error);
2183 if (fp->f_type != DTYPE_VNODE) {
2184 fdrop(fp, td);
2185 return (EOPNOTSUPP);
2186 }
2187
2188 vp = fp->f_vnode;
2189 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
2190 lf.l_whence = SEEK_SET;
2191 lf.l_start = 0;
2192 lf.l_len = 0;
2193 if (uap->how & LOCK_UN) {
2194 lf.l_type = F_UNLCK;
2195 atomic_clear_int(&fp->f_flag, FHASLOCK);
2196 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
2197 goto done2;
2198 }
2199 if (uap->how & LOCK_EX)
2200 lf.l_type = F_WRLCK;
2201 else if (uap->how & LOCK_SH)
2202 lf.l_type = F_RDLCK;
2203 else {
2204 error = EBADF;
2205 goto done2;
2206 }
2207 atomic_set_int(&fp->f_flag, FHASLOCK);
2208 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf,
2209 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT);
2210done2:
2211 fdrop(fp, td);
2212 VFS_UNLOCK_GIANT(vfslocked);
2213 return (error);
2214}
2215/*
2216 * Duplicate the specified descriptor to a free descriptor.
2217 */
2218int
2219dupfdopen(struct thread *td, struct filedesc *fdp, int indx, int dfd, int mode, int error)
2220{
2221 struct file *wfp;
2222 struct file *fp;
2223
2224 /*
2225 * If the to-be-dup'd fd number is greater than the allowed number
2226 * of file descriptors, or the fd to be dup'd has already been
2227 * closed, then reject.
2228 */
2229 FILEDESC_XLOCK(fdp);
2230 if (dfd < 0 || dfd >= fdp->fd_nfiles ||
2231 (wfp = fdp->fd_ofiles[dfd]) == NULL) {
2232 FILEDESC_XUNLOCK(fdp);
2233 return (EBADF);
2234 }
2235
2236 /*
2237 * There are two cases of interest here.
2238 *
2239 * For ENODEV simply dup (dfd) to file descriptor (indx) and return.
2240 *
2241 * For ENXIO steal away the file structure from (dfd) and store it in
2242 * (indx). (dfd) is effectively closed by this operation.
2243 *
2244 * Any other error code is just returned.
2245 */
2246 switch (error) {
2247 case ENODEV:
2248 /*
2249 * Check that the mode the file is being opened for is a
2250 * subset of the mode of the existing descriptor.
2251 */
2252 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) {
2253 FILEDESC_XUNLOCK(fdp);
2254 return (EACCES);
2255 }
2256 fp = fdp->fd_ofiles[indx];
2257 fdp->fd_ofiles[indx] = wfp;
2258 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
2259 if (fp == NULL)
2260 fdused(fdp, indx);
2261 fhold(wfp);
2262 FILEDESC_XUNLOCK(fdp);
2263 if (fp != NULL)
2264 /*
2265 * We now own the reference to fp that the ofiles[]
2266 * array used to own. Release it.
2267 */
2268 fdrop(fp, td);
2269 return (0);
2270
2271 case ENXIO:
2272 /*
2273 * Steal away the file pointer from dfd and stuff it into indx.
2274 */
2275 fp = fdp->fd_ofiles[indx];
2276 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd];
2277 fdp->fd_ofiles[dfd] = NULL;
2278 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
2279 fdp->fd_ofileflags[dfd] = 0;
2280 fdunused(fdp, dfd);
2281 if (fp == NULL)
2282 fdused(fdp, indx);
2283 FILEDESC_XUNLOCK(fdp);
2284
2285 /*
2286 * We now own the reference to fp that the ofiles[] array
2287 * used to own. Release it.
2288 */
2289 if (fp != NULL)
2290 fdrop(fp, td);
2291 return (0);
2292
2293 default:
2294 FILEDESC_XUNLOCK(fdp);
2295 return (error);
2296 }
2297 /* NOTREACHED */
2298}
2299
2300/*
2301 * Scan all active processes to see if any of them have a current or root
2302 * directory of `olddp'. If so, replace them with the new mount point.
2303 */
2304void
2305mountcheckdirs(struct vnode *olddp, struct vnode *newdp)
2306{
2307 struct filedesc *fdp;
2308 struct proc *p;
2309 int nrele;
2310
2311 if (vrefcnt(olddp) == 1)
2312 return;
2313 sx_slock(&allproc_lock);
2314 FOREACH_PROC_IN_SYSTEM(p) {
2315 fdp = fdhold(p);
2316 if (fdp == NULL)
2317 continue;
2318 nrele = 0;
2319 FILEDESC_XLOCK(fdp);
2320 if (fdp->fd_cdir == olddp) {
2321 vref(newdp);
2322 fdp->fd_cdir = newdp;
2323 nrele++;
2324 }
2325 if (fdp->fd_rdir == olddp) {
2326 vref(newdp);
2327 fdp->fd_rdir = newdp;
2328 nrele++;
2329 }
2330 FILEDESC_XUNLOCK(fdp);
2331 fddrop(fdp);
2332 while (nrele--)
2333 vrele(olddp);
2334 }
2335 sx_sunlock(&allproc_lock);
2336 if (rootvnode == olddp) {
2337 vrele(rootvnode);
2338 vref(newdp);
2339 rootvnode = newdp;
2340 }
2341}
2342
2343struct filedesc_to_leader *
2344filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader)
2345{
2346 struct filedesc_to_leader *fdtol;
2347
2348 MALLOC(fdtol, struct filedesc_to_leader *,
2349 sizeof(struct filedesc_to_leader),
2350 M_FILEDESC_TO_LEADER,
2351 M_WAITOK);
2352 fdtol->fdl_refcount = 1;
2353 fdtol->fdl_holdcount = 0;
2354 fdtol->fdl_wakeup = 0;
2355 fdtol->fdl_leader = leader;
2356 if (old != NULL) {
2357 FILEDESC_XLOCK(fdp);
2358 fdtol->fdl_next = old->fdl_next;
2359 fdtol->fdl_prev = old;
2360 old->fdl_next = fdtol;
2361 fdtol->fdl_next->fdl_prev = fdtol;
2362 FILEDESC_XUNLOCK(fdp);
2363 } else {
2364 fdtol->fdl_next = fdtol;
2365 fdtol->fdl_prev = fdtol;
2366 }
2367 return (fdtol);
2368}
2369
2370/*
2371 * Get file structures globally.
2372 */
2373static int
2374sysctl_kern_file(SYSCTL_HANDLER_ARGS)
2375{
2376 struct xfile xf;
2377 struct filedesc *fdp;
2378 struct file *fp;
2379 struct proc *p;
2380 int error, n;
2381
2382 error = sysctl_wire_old_buffer(req, 0);
2383 if (error != 0)
2384 return (error);
2385 if (req->oldptr == NULL) {
2386 n = 0;
2387 sx_slock(&allproc_lock);
2388 FOREACH_PROC_IN_SYSTEM(p) {
2389 if (p->p_state == PRS_NEW)
2390 continue;
2391 fdp = fdhold(p);
2392 if (fdp == NULL)
2393 continue;
2394 /* overestimates sparse tables. */
2395 if (fdp->fd_lastfile > 0)
2396 n += fdp->fd_lastfile;
2397 fddrop(fdp);
2398 }
2399 sx_sunlock(&allproc_lock);
2400 return (SYSCTL_OUT(req, 0, n * sizeof(xf)));
2401 }
2402 error = 0;
2403 bzero(&xf, sizeof(xf));
2404 xf.xf_size = sizeof(xf);
2405 sx_slock(&allproc_lock);
2406 FOREACH_PROC_IN_SYSTEM(p) {
2407 if (p->p_state == PRS_NEW)
2408 continue;
2409 PROC_LOCK(p);
2410 if (p_cansee(req->td, p) != 0) {
2411 PROC_UNLOCK(p);
2412 continue;
2413 }
2414 xf.xf_pid = p->p_pid;
2415 xf.xf_uid = p->p_ucred->cr_uid;
2416 PROC_UNLOCK(p);
2417 fdp = fdhold(p);
2418 if (fdp == NULL)
2419 continue;
2420 FILEDESC_SLOCK(fdp);
2421 for (n = 0; fdp->fd_refcnt > 0 && n < fdp->fd_nfiles; ++n) {
2422 if ((fp = fdp->fd_ofiles[n]) == NULL)
2423 continue;
2424 xf.xf_fd = n;
2425 xf.xf_file = fp;
2426 xf.xf_data = fp->f_data;
2427 xf.xf_vnode = fp->f_vnode;
2428 xf.xf_type = fp->f_type;
2429 xf.xf_count = fp->f_count;
2430 xf.xf_msgcount = 0;
2431 xf.xf_offset = fp->f_offset;
2432 xf.xf_flag = fp->f_flag;
2433 error = SYSCTL_OUT(req, &xf, sizeof(xf));
2434 if (error)
2435 break;
2436 }
2437 FILEDESC_SUNLOCK(fdp);
2438 fddrop(fdp);
2439 if (error)
2440 break;
2441 }
2442 sx_sunlock(&allproc_lock);
2443 return (error);
2444}
2445
2446SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD,
2447 0, 0, sysctl_kern_file, "S,xfile", "Entire file table");
2448
2449/*
2450 * Get per-process file descriptors for use by procstat(1), et al.
2451 */
2452static int
2453sysctl_kern_proc_filedesc(SYSCTL_HANDLER_ARGS)
2454{
2455 char *fullpath, *freepath;
2456 struct kinfo_file *kif;
2457 struct filedesc *fdp;
2458 int error, i, *name;
2459 struct socket *so;
2460 struct vnode *vp;
2461 struct file *fp;
2462 struct proc *p;
2463 int vfslocked;
2464
2465 name = (int *)arg1;
2466 if ((p = pfind((pid_t)name[0])) == NULL)
2467 return (ESRCH);
2468 if ((error = p_candebug(curthread, p))) {
2469 PROC_UNLOCK(p);
2470 return (error);
2471 }
2472 fdp = fdhold(p);
2473 PROC_UNLOCK(p);
2474 kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK);
2475 FILEDESC_SLOCK(fdp);
2476 for (i = 0; i < fdp->fd_nfiles; i++) {
2477 if ((fp = fdp->fd_ofiles[i]) == NULL)
2478 continue;
2479 bzero(kif, sizeof(*kif));
2480 kif->kf_structsize = sizeof(*kif);
2481 vp = NULL;
2482 so = NULL;
2483 kif->kf_fd = i;
2484 switch (fp->f_type) {
2485 case DTYPE_VNODE:
2486 kif->kf_type = KF_TYPE_VNODE;
2487 vp = fp->f_vnode;
2488 break;
2489
2490 case DTYPE_SOCKET:
2491 kif->kf_type = KF_TYPE_SOCKET;
2492 so = fp->f_data;
2493 break;
2494
2495 case DTYPE_PIPE:
2496 kif->kf_type = KF_TYPE_PIPE;
2497 break;
2498
2499 case DTYPE_FIFO:
2500 kif->kf_type = KF_TYPE_FIFO;
2501 vp = fp->f_vnode;
2502 vref(vp);
2503 break;
2504
2505 case DTYPE_KQUEUE:
2506 kif->kf_type = KF_TYPE_KQUEUE;
2507 break;
2508
2509 case DTYPE_CRYPTO:
2510 kif->kf_type = KF_TYPE_CRYPTO;
2511 break;
2512
2513 case DTYPE_MQUEUE:
2514 kif->kf_type = KF_TYPE_MQUEUE;
2515 break;
2516
2517 default:
2518 kif->kf_type = KF_TYPE_UNKNOWN;
2519 break;
2520 }
2521 kif->kf_ref_count = fp->f_count;
2522 if (fp->f_flag & FREAD)
2523 kif->kf_flags |= KF_FLAG_READ;
2524 if (fp->f_flag & FWRITE)
2525 kif->kf_flags |= KF_FLAG_WRITE;
2526 if (fp->f_flag & FAPPEND)
2527 kif->kf_flags |= KF_FLAG_APPEND;
2528 if (fp->f_flag & FASYNC)
2529 kif->kf_flags |= KF_FLAG_ASYNC;
2530 if (fp->f_flag & FFSYNC)
2531 kif->kf_flags |= KF_FLAG_FSYNC;
2532 if (fp->f_flag & FNONBLOCK)
2533 kif->kf_flags |= KF_FLAG_NONBLOCK;
2534 if (fp->f_flag & O_DIRECT)
2535 kif->kf_flags |= KF_FLAG_DIRECT;
2536 if (fp->f_flag & FHASLOCK)
2537 kif->kf_flags |= KF_FLAG_HASLOCK;
2538 kif->kf_offset = fp->f_offset;
2539 if (vp != NULL) {
2540 vref(vp);
2541 switch (vp->v_type) {
2542 case VNON:
2543 kif->kf_vnode_type = KF_VTYPE_VNON;
2544 break;
2545 case VREG:
2546 kif->kf_vnode_type = KF_VTYPE_VREG;
2547 break;
2548 case VDIR:
2549 kif->kf_vnode_type = KF_VTYPE_VDIR;
2550 break;
2551 case VBLK:
2552 kif->kf_vnode_type = KF_VTYPE_VBLK;
2553 break;
2554 case VCHR:
2555 kif->kf_vnode_type = KF_VTYPE_VCHR;
2556 break;
2557 case VLNK:
2558 kif->kf_vnode_type = KF_VTYPE_VLNK;
2559 break;
2560 case VSOCK:
2561 kif->kf_vnode_type = KF_VTYPE_VSOCK;
2562 break;
2563 case VFIFO:
2564 kif->kf_vnode_type = KF_VTYPE_VFIFO;
2565 break;
2566 case VBAD:
2567 kif->kf_vnode_type = KF_VTYPE_VBAD;
2568 break;
2569 default:
2570 kif->kf_vnode_type = KF_VTYPE_UNKNOWN;
2571 break;
2572 }
2573 /*
2574 * It is OK to drop the filedesc lock here as we will
2575 * re-validate and re-evaluate its properties when
2576 * the loop continues.
2577 */
2578 freepath = NULL;
2579 fullpath = "-";
2580 FILEDESC_SUNLOCK(fdp);
2581 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
2582 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, curthread);
2583 vn_fullpath(curthread, vp, &fullpath, &freepath);
2584 vput(vp);
2585 VFS_UNLOCK_GIANT(vfslocked);
2586 strlcpy(kif->kf_path, fullpath,
2587 sizeof(kif->kf_path));
2588 if (freepath != NULL)
2589 free(freepath, M_TEMP);
2590 FILEDESC_SLOCK(fdp);
2591 }
2592 if (so != NULL) {
2593 struct sockaddr *sa;
2594
2595 if (so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa)
2596 == 0 && sa->sa_len <= sizeof(kif->kf_sa_local)) {
2597 bcopy(sa, &kif->kf_sa_local, sa->sa_len);
2598 free(sa, M_SONAME);
2599 }
2600 if (so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa)
2601 == 00 && sa->sa_len <= sizeof(kif->kf_sa_peer)) {
2602 bcopy(sa, &kif->kf_sa_peer, sa->sa_len);
2603 free(sa, M_SONAME);
2604 }
2605 kif->kf_sock_domain =
2606 so->so_proto->pr_domain->dom_family;
2607 kif->kf_sock_type = so->so_type;
2608 kif->kf_sock_protocol = so->so_proto->pr_protocol;
2609 }
2610 error = SYSCTL_OUT(req, kif, sizeof(*kif));
2611 if (error)
2612 break;
2613 }
2614 FILEDESC_SUNLOCK(fdp);
2615 fddrop(fdp);
2616 free(kif, M_TEMP);
2617 return (0);
2618}
2619
2620static SYSCTL_NODE(_kern_proc, KERN_PROC_FILEDESC, filedesc, CTLFLAG_RD,
2621 sysctl_kern_proc_filedesc, "Process filedesc entries");
2622
2623#ifdef DDB
2624/*
2625 * For the purposes of debugging, generate a human-readable string for the
2626 * file type.
2627 */
2628static const char *
2629file_type_to_name(short type)
2630{
2631
2632 switch (type) {
2633 case 0:
2634 return ("zero");
2635 case DTYPE_VNODE:
2636 return ("vnod");
2637 case DTYPE_SOCKET:
2638 return ("sock");
2639 case DTYPE_PIPE:
2640 return ("pipe");
2641 case DTYPE_FIFO:
2642 return ("fifo");
2643 case DTYPE_KQUEUE:
2644 return ("kque");
2645 case DTYPE_CRYPTO:
2646 return ("crpt");
2647 case DTYPE_MQUEUE:
2648 return ("mque");
| 39
40#include "opt_compat.h"
41#include "opt_ddb.h"
42
43#include <sys/param.h>
44#include <sys/systm.h>
45
46#include <sys/conf.h>
47#include <sys/domain.h>
48#include <sys/fcntl.h>
49#include <sys/file.h>
50#include <sys/filedesc.h>
51#include <sys/filio.h>
52#include <sys/jail.h>
53#include <sys/kernel.h>
54#include <sys/limits.h>
55#include <sys/lock.h>
56#include <sys/malloc.h>
57#include <sys/mount.h>
58#include <sys/mqueue.h>
59#include <sys/mutex.h>
60#include <sys/namei.h>
61#include <sys/priv.h>
62#include <sys/proc.h>
63#include <sys/protosw.h>
64#include <sys/resourcevar.h>
65#include <sys/signalvar.h>
66#include <sys/socketvar.h>
67#include <sys/stat.h>
68#include <sys/sx.h>
69#include <sys/syscallsubr.h>
70#include <sys/sysctl.h>
71#include <sys/sysproto.h>
72#include <sys/unistd.h>
73#include <sys/user.h>
74#include <sys/vnode.h>
75
76#include <security/audit/audit.h>
77
78#include <vm/uma.h>
79
80#include <ddb/ddb.h>
81
82static MALLOC_DEFINE(M_FILEDESC, "filedesc", "Open file descriptor table");
83static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "filedesc_to_leader",
84 "file desc to leader structures");
85static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
86
87static uma_zone_t file_zone;
88
89
90/* How to treat 'new' parameter when allocating a fd for do_dup(). */
91enum dup_type { DUP_VARIABLE, DUP_FIXED };
92
93static int do_dup(struct thread *td, enum dup_type type, int old, int new,
94 register_t *retval);
95static int fd_first_free(struct filedesc *, int, int);
96static int fd_last_used(struct filedesc *, int, int);
97static void fdgrowtable(struct filedesc *, int);
98static void fdunused(struct filedesc *fdp, int fd);
99static void fdused(struct filedesc *fdp, int fd);
100
101/*
102 * A process is initially started out with NDFILE descriptors stored within
103 * this structure, selected to be enough for typical applications based on
104 * the historical limit of 20 open files (and the usage of descriptors by
105 * shells). If these descriptors are exhausted, a larger descriptor table
106 * may be allocated, up to a process' resource limit; the internal arrays
107 * are then unused.
108 */
109#define NDFILE 20
110#define NDSLOTSIZE sizeof(NDSLOTTYPE)
111#define NDENTRIES (NDSLOTSIZE * __CHAR_BIT)
112#define NDSLOT(x) ((x) / NDENTRIES)
113#define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES))
114#define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES)
115
116/*
117 * Storage required per open file descriptor.
118 */
119#define OFILESIZE (sizeof(struct file *) + sizeof(char))
120
121/*
122 * Basic allocation of descriptors:
123 * one of the above, plus arrays for NDFILE descriptors.
124 */
125struct filedesc0 {
126 struct filedesc fd_fd;
127 /*
128 * These arrays are used when the number of open files is
129 * <= NDFILE, and are then pointed to by the pointers above.
130 */
131 struct file *fd_dfiles[NDFILE];
132 char fd_dfileflags[NDFILE];
133 NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)];
134};
135
136/*
137 * Descriptor management.
138 */
139volatile int openfiles; /* actual number of open files */
140struct mtx sigio_lock; /* mtx to protect pointers to sigio */
141void (*mq_fdclose)(struct thread *td, int fd, struct file *fp);
142
143/* A mutex to protect the association between a proc and filedesc. */
144static struct mtx fdesc_mtx;
145
146/*
147 * Find the first zero bit in the given bitmap, starting at low and not
148 * exceeding size - 1.
149 */
150static int
151fd_first_free(struct filedesc *fdp, int low, int size)
152{
153 NDSLOTTYPE *map = fdp->fd_map;
154 NDSLOTTYPE mask;
155 int off, maxoff;
156
157 if (low >= size)
158 return (low);
159
160 off = NDSLOT(low);
161 if (low % NDENTRIES) {
162 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES)));
163 if ((mask &= ~map[off]) != 0UL)
164 return (off * NDENTRIES + ffsl(mask) - 1);
165 ++off;
166 }
167 for (maxoff = NDSLOTS(size); off < maxoff; ++off)
168 if (map[off] != ~0UL)
169 return (off * NDENTRIES + ffsl(~map[off]) - 1);
170 return (size);
171}
172
173/*
174 * Find the highest non-zero bit in the given bitmap, starting at low and
175 * not exceeding size - 1.
176 */
177static int
178fd_last_used(struct filedesc *fdp, int low, int size)
179{
180 NDSLOTTYPE *map = fdp->fd_map;
181 NDSLOTTYPE mask;
182 int off, minoff;
183
184 if (low >= size)
185 return (-1);
186
187 off = NDSLOT(size);
188 if (size % NDENTRIES) {
189 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES));
190 if ((mask &= map[off]) != 0)
191 return (off * NDENTRIES + flsl(mask) - 1);
192 --off;
193 }
194 for (minoff = NDSLOT(low); off >= minoff; --off)
195 if (map[off] != 0)
196 return (off * NDENTRIES + flsl(map[off]) - 1);
197 return (low - 1);
198}
199
200static int
201fdisused(struct filedesc *fdp, int fd)
202{
203 KASSERT(fd >= 0 && fd < fdp->fd_nfiles,
204 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles));
205 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0);
206}
207
208/*
209 * Mark a file descriptor as used.
210 */
211static void
212fdused(struct filedesc *fdp, int fd)
213{
214
215 FILEDESC_XLOCK_ASSERT(fdp);
216 KASSERT(!fdisused(fdp, fd),
217 ("fd already used"));
218
219 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd);
220 if (fd > fdp->fd_lastfile)
221 fdp->fd_lastfile = fd;
222 if (fd == fdp->fd_freefile)
223 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles);
224}
225
226/*
227 * Mark a file descriptor as unused.
228 */
229static void
230fdunused(struct filedesc *fdp, int fd)
231{
232
233 FILEDESC_XLOCK_ASSERT(fdp);
234 KASSERT(fdisused(fdp, fd),
235 ("fd is already unused"));
236 KASSERT(fdp->fd_ofiles[fd] == NULL,
237 ("fd is still in use"));
238
239 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd);
240 if (fd < fdp->fd_freefile)
241 fdp->fd_freefile = fd;
242 if (fd == fdp->fd_lastfile)
243 fdp->fd_lastfile = fd_last_used(fdp, 0, fd);
244}
245
246/*
247 * System calls on descriptors.
248 */
249#ifndef _SYS_SYSPROTO_H_
250struct getdtablesize_args {
251 int dummy;
252};
253#endif
254/* ARGSUSED */
255int
256getdtablesize(struct thread *td, struct getdtablesize_args *uap)
257{
258 struct proc *p = td->td_proc;
259
260 PROC_LOCK(p);
261 td->td_retval[0] =
262 min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
263 PROC_UNLOCK(p);
264 return (0);
265}
266
267/*
268 * Duplicate a file descriptor to a particular value.
269 *
270 * Note: keep in mind that a potential race condition exists when closing
271 * descriptors from a shared descriptor table (via rfork).
272 */
273#ifndef _SYS_SYSPROTO_H_
274struct dup2_args {
275 u_int from;
276 u_int to;
277};
278#endif
279/* ARGSUSED */
280int
281dup2(struct thread *td, struct dup2_args *uap)
282{
283
284 return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to,
285 td->td_retval));
286}
287
288/*
289 * Duplicate a file descriptor.
290 */
291#ifndef _SYS_SYSPROTO_H_
292struct dup_args {
293 u_int fd;
294};
295#endif
296/* ARGSUSED */
297int
298dup(struct thread *td, struct dup_args *uap)
299{
300
301 return (do_dup(td, DUP_VARIABLE, (int)uap->fd, 0, td->td_retval));
302}
303
304/*
305 * The file control system call.
306 */
307#ifndef _SYS_SYSPROTO_H_
308struct fcntl_args {
309 int fd;
310 int cmd;
311 long arg;
312};
313#endif
314/* ARGSUSED */
315int
316fcntl(struct thread *td, struct fcntl_args *uap)
317{
318 struct flock fl;
319 intptr_t arg;
320 int error;
321
322 error = 0;
323 switch (uap->cmd) {
324 case F_GETLK:
325 case F_SETLK:
326 case F_SETLKW:
327 error = copyin((void *)(intptr_t)uap->arg, &fl, sizeof(fl));
328 arg = (intptr_t)&fl;
329 break;
330 default:
331 arg = uap->arg;
332 break;
333 }
334 if (error)
335 return (error);
336 error = kern_fcntl(td, uap->fd, uap->cmd, arg);
337 if (error)
338 return (error);
339 if (uap->cmd == F_GETLK)
340 error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl));
341 return (error);
342}
343
344static inline struct file *
345fdtofp(int fd, struct filedesc *fdp)
346{
347 struct file *fp;
348
349 FILEDESC_LOCK_ASSERT(fdp);
350 if ((unsigned)fd >= fdp->fd_nfiles ||
351 (fp = fdp->fd_ofiles[fd]) == NULL)
352 return (NULL);
353 return (fp);
354}
355
356int
357kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg)
358{
359 struct filedesc *fdp;
360 struct flock *flp;
361 struct file *fp;
362 struct proc *p;
363 char *pop;
364 struct vnode *vp;
365 u_int newmin;
366 int error, flg, tmp;
367 int vfslocked;
368
369 vfslocked = 0;
370 error = 0;
371 flg = F_POSIX;
372 p = td->td_proc;
373 fdp = p->p_fd;
374
375 switch (cmd) {
376 case F_DUPFD:
377 FILEDESC_SLOCK(fdp);
378 if ((fp = fdtofp(fd, fdp)) == NULL) {
379 FILEDESC_SUNLOCK(fdp);
380 error = EBADF;
381 break;
382 }
383 FILEDESC_SUNLOCK(fdp);
384 newmin = arg;
385 PROC_LOCK(p);
386 if (newmin >= lim_cur(p, RLIMIT_NOFILE) ||
387 newmin >= maxfilesperproc) {
388 PROC_UNLOCK(p);
389 error = EINVAL;
390 break;
391 }
392 PROC_UNLOCK(p);
393 error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval);
394 break;
395
396 case F_GETFD:
397 FILEDESC_SLOCK(fdp);
398 if ((fp = fdtofp(fd, fdp)) == NULL) {
399 FILEDESC_SUNLOCK(fdp);
400 error = EBADF;
401 break;
402 }
403 pop = &fdp->fd_ofileflags[fd];
404 td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0;
405 FILEDESC_SUNLOCK(fdp);
406 break;
407
408 case F_SETFD:
409 FILEDESC_XLOCK(fdp);
410 if ((fp = fdtofp(fd, fdp)) == NULL) {
411 FILEDESC_XUNLOCK(fdp);
412 error = EBADF;
413 break;
414 }
415 pop = &fdp->fd_ofileflags[fd];
416 *pop = (*pop &~ UF_EXCLOSE) |
417 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0);
418 FILEDESC_XUNLOCK(fdp);
419 break;
420
421 case F_GETFL:
422 FILEDESC_SLOCK(fdp);
423 if ((fp = fdtofp(fd, fdp)) == NULL) {
424 FILEDESC_SUNLOCK(fdp);
425 error = EBADF;
426 break;
427 }
428 td->td_retval[0] = OFLAGS(fp->f_flag);
429 FILEDESC_SUNLOCK(fdp);
430 break;
431
432 case F_SETFL:
433 FILEDESC_SLOCK(fdp);
434 if ((fp = fdtofp(fd, fdp)) == NULL) {
435 FILEDESC_SUNLOCK(fdp);
436 error = EBADF;
437 break;
438 }
439 fhold(fp);
440 FILEDESC_SUNLOCK(fdp);
441 do {
442 tmp = flg = fp->f_flag;
443 tmp &= ~FCNTLFLAGS;
444 tmp |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS;
445 } while(atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0);
446 tmp = fp->f_flag & FNONBLOCK;
447 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
448 if (error) {
449 fdrop(fp, td);
450 break;
451 }
452 tmp = fp->f_flag & FASYNC;
453 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td);
454 if (error == 0) {
455 fdrop(fp, td);
456 break;
457 }
458 atomic_clear_int(&fp->f_flag, FNONBLOCK);
459 tmp = 0;
460 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
461 fdrop(fp, td);
462 break;
463
464 case F_GETOWN:
465 FILEDESC_SLOCK(fdp);
466 if ((fp = fdtofp(fd, fdp)) == NULL) {
467 FILEDESC_SUNLOCK(fdp);
468 error = EBADF;
469 break;
470 }
471 fhold(fp);
472 FILEDESC_SUNLOCK(fdp);
473 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td);
474 if (error == 0)
475 td->td_retval[0] = tmp;
476 fdrop(fp, td);
477 break;
478
479 case F_SETOWN:
480 FILEDESC_SLOCK(fdp);
481 if ((fp = fdtofp(fd, fdp)) == NULL) {
482 FILEDESC_SUNLOCK(fdp);
483 error = EBADF;
484 break;
485 }
486 fhold(fp);
487 FILEDESC_SUNLOCK(fdp);
488 tmp = arg;
489 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td);
490 fdrop(fp, td);
491 break;
492
493 case F_SETLKW:
494 flg |= F_WAIT;
495 /* FALLTHROUGH F_SETLK */
496
497 case F_SETLK:
498 FILEDESC_SLOCK(fdp);
499 if ((fp = fdtofp(fd, fdp)) == NULL) {
500 FILEDESC_SUNLOCK(fdp);
501 error = EBADF;
502 break;
503 }
504 if (fp->f_type != DTYPE_VNODE) {
505 FILEDESC_SUNLOCK(fdp);
506 error = EBADF;
507 break;
508 }
509 flp = (struct flock *)arg;
510 if (flp->l_whence == SEEK_CUR) {
511 if (fp->f_offset < 0 ||
512 (flp->l_start > 0 &&
513 fp->f_offset > OFF_MAX - flp->l_start)) {
514 FILEDESC_SUNLOCK(fdp);
515 error = EOVERFLOW;
516 break;
517 }
518 flp->l_start += fp->f_offset;
519 }
520
521 /*
522 * VOP_ADVLOCK() may block.
523 */
524 fhold(fp);
525 FILEDESC_SUNLOCK(fdp);
526 vp = fp->f_vnode;
527 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
528 switch (flp->l_type) {
529 case F_RDLCK:
530 if ((fp->f_flag & FREAD) == 0) {
531 error = EBADF;
532 break;
533 }
534 PROC_LOCK(p->p_leader);
535 p->p_leader->p_flag |= P_ADVLOCK;
536 PROC_UNLOCK(p->p_leader);
537 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
538 flp, flg);
539 break;
540 case F_WRLCK:
541 if ((fp->f_flag & FWRITE) == 0) {
542 error = EBADF;
543 break;
544 }
545 PROC_LOCK(p->p_leader);
546 p->p_leader->p_flag |= P_ADVLOCK;
547 PROC_UNLOCK(p->p_leader);
548 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
549 flp, flg);
550 break;
551 case F_UNLCK:
552 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
553 flp, F_POSIX);
554 break;
555 default:
556 error = EINVAL;
557 break;
558 }
559 VFS_UNLOCK_GIANT(vfslocked);
560 vfslocked = 0;
561 /* Check for race with close */
562 FILEDESC_SLOCK(fdp);
563 if ((unsigned) fd >= fdp->fd_nfiles ||
564 fp != fdp->fd_ofiles[fd]) {
565 FILEDESC_SUNLOCK(fdp);
566 flp->l_whence = SEEK_SET;
567 flp->l_start = 0;
568 flp->l_len = 0;
569 flp->l_type = F_UNLCK;
570 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
571 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
572 F_UNLCK, flp, F_POSIX);
573 VFS_UNLOCK_GIANT(vfslocked);
574 vfslocked = 0;
575 } else
576 FILEDESC_SUNLOCK(fdp);
577 fdrop(fp, td);
578 break;
579
580 case F_GETLK:
581 FILEDESC_SLOCK(fdp);
582 if ((fp = fdtofp(fd, fdp)) == NULL) {
583 FILEDESC_SUNLOCK(fdp);
584 error = EBADF;
585 break;
586 }
587 if (fp->f_type != DTYPE_VNODE) {
588 FILEDESC_SUNLOCK(fdp);
589 error = EBADF;
590 break;
591 }
592 flp = (struct flock *)arg;
593 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK &&
594 flp->l_type != F_UNLCK) {
595 FILEDESC_SUNLOCK(fdp);
596 error = EINVAL;
597 break;
598 }
599 if (flp->l_whence == SEEK_CUR) {
600 if ((flp->l_start > 0 &&
601 fp->f_offset > OFF_MAX - flp->l_start) ||
602 (flp->l_start < 0 &&
603 fp->f_offset < OFF_MIN - flp->l_start)) {
604 FILEDESC_SUNLOCK(fdp);
605 error = EOVERFLOW;
606 break;
607 }
608 flp->l_start += fp->f_offset;
609 }
610 /*
611 * VOP_ADVLOCK() may block.
612 */
613 fhold(fp);
614 FILEDESC_SUNLOCK(fdp);
615 vp = fp->f_vnode;
616 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
617 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp,
618 F_POSIX);
619 VFS_UNLOCK_GIANT(vfslocked);
620 vfslocked = 0;
621 fdrop(fp, td);
622 break;
623 default:
624 error = EINVAL;
625 break;
626 }
627 VFS_UNLOCK_GIANT(vfslocked);
628 return (error);
629}
630
631/*
632 * Common code for dup, dup2, and fcntl(F_DUPFD).
633 */
634static int
635do_dup(struct thread *td, enum dup_type type, int old, int new,
636 register_t *retval)
637{
638 struct filedesc *fdp;
639 struct proc *p;
640 struct file *fp;
641 struct file *delfp;
642 int error, holdleaders, maxfd;
643
644 KASSERT((type == DUP_VARIABLE || type == DUP_FIXED),
645 ("invalid dup type %d", type));
646
647 p = td->td_proc;
648 fdp = p->p_fd;
649
650 /*
651 * Verify we have a valid descriptor to dup from and possibly to
652 * dup to.
653 */
654 if (old < 0 || new < 0)
655 return (EBADF);
656 PROC_LOCK(p);
657 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
658 PROC_UNLOCK(p);
659 if (new >= maxfd)
660 return (EMFILE);
661
662 FILEDESC_XLOCK(fdp);
663 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) {
664 FILEDESC_XUNLOCK(fdp);
665 return (EBADF);
666 }
667 if (type == DUP_FIXED && old == new) {
668 *retval = new;
669 FILEDESC_XUNLOCK(fdp);
670 return (0);
671 }
672 fp = fdp->fd_ofiles[old];
673 fhold(fp);
674
675 /*
676 * If the caller specified a file descriptor, make sure the file
677 * table is large enough to hold it, and grab it. Otherwise, just
678 * allocate a new descriptor the usual way. Since the filedesc
679 * lock may be temporarily dropped in the process, we have to look
680 * out for a race.
681 */
682 if (type == DUP_FIXED) {
683 if (new >= fdp->fd_nfiles)
684 fdgrowtable(fdp, new + 1);
685 if (fdp->fd_ofiles[new] == NULL)
686 fdused(fdp, new);
687 } else {
688 if ((error = fdalloc(td, new, &new)) != 0) {
689 FILEDESC_XUNLOCK(fdp);
690 fdrop(fp, td);
691 return (error);
692 }
693 }
694
695 /*
696 * If the old file changed out from under us then treat it as a
697 * bad file descriptor. Userland should do its own locking to
698 * avoid this case.
699 */
700 if (fdp->fd_ofiles[old] != fp) {
701 /* we've allocated a descriptor which we won't use */
702 if (fdp->fd_ofiles[new] == NULL)
703 fdunused(fdp, new);
704 FILEDESC_XUNLOCK(fdp);
705 fdrop(fp, td);
706 return (EBADF);
707 }
708 KASSERT(old != new,
709 ("new fd is same as old"));
710
711 /*
712 * Save info on the descriptor being overwritten. We cannot close
713 * it without introducing an ownership race for the slot, since we
714 * need to drop the filedesc lock to call closef().
715 *
716 * XXX this duplicates parts of close().
717 */
718 delfp = fdp->fd_ofiles[new];
719 holdleaders = 0;
720 if (delfp != NULL) {
721 if (td->td_proc->p_fdtol != NULL) {
722 /*
723 * Ask fdfree() to sleep to ensure that all relevant
724 * process leaders can be traversed in closef().
725 */
726 fdp->fd_holdleaderscount++;
727 holdleaders = 1;
728 }
729 }
730
731 /*
732 * Duplicate the source descriptor
733 */
734 fdp->fd_ofiles[new] = fp;
735 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
736 if (new > fdp->fd_lastfile)
737 fdp->fd_lastfile = new;
738 *retval = new;
739
740 /*
741 * If we dup'd over a valid file, we now own the reference to it
742 * and must dispose of it using closef() semantics (as if a
743 * close() were performed on it).
744 *
745 * XXX this duplicates parts of close().
746 */
747 if (delfp != NULL) {
748 knote_fdclose(td, new);
749 if (delfp->f_type == DTYPE_MQUEUE)
750 mq_fdclose(td, new, delfp);
751 FILEDESC_XUNLOCK(fdp);
752 (void) closef(delfp, td);
753 if (holdleaders) {
754 FILEDESC_XLOCK(fdp);
755 fdp->fd_holdleaderscount--;
756 if (fdp->fd_holdleaderscount == 0 &&
757 fdp->fd_holdleaderswakeup != 0) {
758 fdp->fd_holdleaderswakeup = 0;
759 wakeup(&fdp->fd_holdleaderscount);
760 }
761 FILEDESC_XUNLOCK(fdp);
762 }
763 } else {
764 FILEDESC_XUNLOCK(fdp);
765 }
766 return (0);
767}
768
769/*
770 * If sigio is on the list associated with a process or process group,
771 * disable signalling from the device, remove sigio from the list and
772 * free sigio.
773 */
774void
775funsetown(struct sigio **sigiop)
776{
777 struct sigio *sigio;
778
779 SIGIO_LOCK();
780 sigio = *sigiop;
781 if (sigio == NULL) {
782 SIGIO_UNLOCK();
783 return;
784 }
785 *(sigio->sio_myref) = NULL;
786 if ((sigio)->sio_pgid < 0) {
787 struct pgrp *pg = (sigio)->sio_pgrp;
788 PGRP_LOCK(pg);
789 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
790 sigio, sio_pgsigio);
791 PGRP_UNLOCK(pg);
792 } else {
793 struct proc *p = (sigio)->sio_proc;
794 PROC_LOCK(p);
795 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
796 sigio, sio_pgsigio);
797 PROC_UNLOCK(p);
798 }
799 SIGIO_UNLOCK();
800 crfree(sigio->sio_ucred);
801 FREE(sigio, M_SIGIO);
802}
803
804/*
805 * Free a list of sigio structures.
806 * We only need to lock the SIGIO_LOCK because we have made ourselves
807 * inaccessible to callers of fsetown and therefore do not need to lock
808 * the proc or pgrp struct for the list manipulation.
809 */
810void
811funsetownlst(struct sigiolst *sigiolst)
812{
813 struct proc *p;
814 struct pgrp *pg;
815 struct sigio *sigio;
816
817 sigio = SLIST_FIRST(sigiolst);
818 if (sigio == NULL)
819 return;
820 p = NULL;
821 pg = NULL;
822
823 /*
824 * Every entry of the list should belong
825 * to a single proc or pgrp.
826 */
827 if (sigio->sio_pgid < 0) {
828 pg = sigio->sio_pgrp;
829 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED);
830 } else /* if (sigio->sio_pgid > 0) */ {
831 p = sigio->sio_proc;
832 PROC_LOCK_ASSERT(p, MA_NOTOWNED);
833 }
834
835 SIGIO_LOCK();
836 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) {
837 *(sigio->sio_myref) = NULL;
838 if (pg != NULL) {
839 KASSERT(sigio->sio_pgid < 0,
840 ("Proc sigio in pgrp sigio list"));
841 KASSERT(sigio->sio_pgrp == pg,
842 ("Bogus pgrp in sigio list"));
843 PGRP_LOCK(pg);
844 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio,
845 sio_pgsigio);
846 PGRP_UNLOCK(pg);
847 } else /* if (p != NULL) */ {
848 KASSERT(sigio->sio_pgid > 0,
849 ("Pgrp sigio in proc sigio list"));
850 KASSERT(sigio->sio_proc == p,
851 ("Bogus proc in sigio list"));
852 PROC_LOCK(p);
853 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio,
854 sio_pgsigio);
855 PROC_UNLOCK(p);
856 }
857 SIGIO_UNLOCK();
858 crfree(sigio->sio_ucred);
859 FREE(sigio, M_SIGIO);
860 SIGIO_LOCK();
861 }
862 SIGIO_UNLOCK();
863}
864
865/*
866 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg).
867 *
868 * After permission checking, add a sigio structure to the sigio list for
869 * the process or process group.
870 */
871int
872fsetown(pid_t pgid, struct sigio **sigiop)
873{
874 struct proc *proc;
875 struct pgrp *pgrp;
876 struct sigio *sigio;
877 int ret;
878
879 if (pgid == 0) {
880 funsetown(sigiop);
881 return (0);
882 }
883
884 ret = 0;
885
886 /* Allocate and fill in the new sigio out of locks. */
887 MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK);
888 sigio->sio_pgid = pgid;
889 sigio->sio_ucred = crhold(curthread->td_ucred);
890 sigio->sio_myref = sigiop;
891
892 sx_slock(&proctree_lock);
893 if (pgid > 0) {
894 proc = pfind(pgid);
895 if (proc == NULL) {
896 ret = ESRCH;
897 goto fail;
898 }
899
900 /*
901 * Policy - Don't allow a process to FSETOWN a process
902 * in another session.
903 *
904 * Remove this test to allow maximum flexibility or
905 * restrict FSETOWN to the current process or process
906 * group for maximum safety.
907 */
908 PROC_UNLOCK(proc);
909 if (proc->p_session != curthread->td_proc->p_session) {
910 ret = EPERM;
911 goto fail;
912 }
913
914 pgrp = NULL;
915 } else /* if (pgid < 0) */ {
916 pgrp = pgfind(-pgid);
917 if (pgrp == NULL) {
918 ret = ESRCH;
919 goto fail;
920 }
921 PGRP_UNLOCK(pgrp);
922
923 /*
924 * Policy - Don't allow a process to FSETOWN a process
925 * in another session.
926 *
927 * Remove this test to allow maximum flexibility or
928 * restrict FSETOWN to the current process or process
929 * group for maximum safety.
930 */
931 if (pgrp->pg_session != curthread->td_proc->p_session) {
932 ret = EPERM;
933 goto fail;
934 }
935
936 proc = NULL;
937 }
938 funsetown(sigiop);
939 if (pgid > 0) {
940 PROC_LOCK(proc);
941 /*
942 * Since funsetownlst() is called without the proctree
943 * locked, we need to check for P_WEXIT.
944 * XXX: is ESRCH correct?
945 */
946 if ((proc->p_flag & P_WEXIT) != 0) {
947 PROC_UNLOCK(proc);
948 ret = ESRCH;
949 goto fail;
950 }
951 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
952 sigio->sio_proc = proc;
953 PROC_UNLOCK(proc);
954 } else {
955 PGRP_LOCK(pgrp);
956 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
957 sigio->sio_pgrp = pgrp;
958 PGRP_UNLOCK(pgrp);
959 }
960 sx_sunlock(&proctree_lock);
961 SIGIO_LOCK();
962 *sigiop = sigio;
963 SIGIO_UNLOCK();
964 return (0);
965
966fail:
967 sx_sunlock(&proctree_lock);
968 crfree(sigio->sio_ucred);
969 FREE(sigio, M_SIGIO);
970 return (ret);
971}
972
973/*
974 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
975 */
976pid_t
977fgetown(sigiop)
978 struct sigio **sigiop;
979{
980 pid_t pgid;
981
982 SIGIO_LOCK();
983 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0;
984 SIGIO_UNLOCK();
985 return (pgid);
986}
987
988/*
989 * Close a file descriptor.
990 */
991#ifndef _SYS_SYSPROTO_H_
992struct close_args {
993 int fd;
994};
995#endif
996/* ARGSUSED */
997int
998close(td, uap)
999 struct thread *td;
1000 struct close_args *uap;
1001{
1002
1003 return (kern_close(td, uap->fd));
1004}
1005
1006int
1007kern_close(td, fd)
1008 struct thread *td;
1009 int fd;
1010{
1011 struct filedesc *fdp;
1012 struct file *fp;
1013 int error;
1014 int holdleaders;
1015
1016 error = 0;
1017 holdleaders = 0;
1018 fdp = td->td_proc->p_fd;
1019
1020 AUDIT_SYSCLOSE(td, fd);
1021
1022 FILEDESC_XLOCK(fdp);
1023 if ((unsigned)fd >= fdp->fd_nfiles ||
1024 (fp = fdp->fd_ofiles[fd]) == NULL) {
1025 FILEDESC_XUNLOCK(fdp);
1026 return (EBADF);
1027 }
1028 fdp->fd_ofiles[fd] = NULL;
1029 fdp->fd_ofileflags[fd] = 0;
1030 fdunused(fdp, fd);
1031 if (td->td_proc->p_fdtol != NULL) {
1032 /*
1033 * Ask fdfree() to sleep to ensure that all relevant
1034 * process leaders can be traversed in closef().
1035 */
1036 fdp->fd_holdleaderscount++;
1037 holdleaders = 1;
1038 }
1039
1040 /*
1041 * We now hold the fp reference that used to be owned by the
1042 * descriptor array. We have to unlock the FILEDESC *AFTER*
1043 * knote_fdclose to prevent a race of the fd getting opened, a knote
1044 * added, and deleteing a knote for the new fd.
1045 */
1046 knote_fdclose(td, fd);
1047 if (fp->f_type == DTYPE_MQUEUE)
1048 mq_fdclose(td, fd, fp);
1049 FILEDESC_XUNLOCK(fdp);
1050
1051 error = closef(fp, td);
1052 if (holdleaders) {
1053 FILEDESC_XLOCK(fdp);
1054 fdp->fd_holdleaderscount--;
1055 if (fdp->fd_holdleaderscount == 0 &&
1056 fdp->fd_holdleaderswakeup != 0) {
1057 fdp->fd_holdleaderswakeup = 0;
1058 wakeup(&fdp->fd_holdleaderscount);
1059 }
1060 FILEDESC_XUNLOCK(fdp);
1061 }
1062 return (error);
1063}
1064
1065#if defined(COMPAT_43)
1066/*
1067 * Return status information about a file descriptor.
1068 */
1069#ifndef _SYS_SYSPROTO_H_
1070struct ofstat_args {
1071 int fd;
1072 struct ostat *sb;
1073};
1074#endif
1075/* ARGSUSED */
1076int
1077ofstat(struct thread *td, struct ofstat_args *uap)
1078{
1079 struct ostat oub;
1080 struct stat ub;
1081 int error;
1082
1083 error = kern_fstat(td, uap->fd, &ub);
1084 if (error == 0) {
1085 cvtstat(&ub, &oub);
1086 error = copyout(&oub, uap->sb, sizeof(oub));
1087 }
1088 return (error);
1089}
1090#endif /* COMPAT_43 */
1091
1092/*
1093 * Return status information about a file descriptor.
1094 */
1095#ifndef _SYS_SYSPROTO_H_
1096struct fstat_args {
1097 int fd;
1098 struct stat *sb;
1099};
1100#endif
1101/* ARGSUSED */
1102int
1103fstat(struct thread *td, struct fstat_args *uap)
1104{
1105 struct stat ub;
1106 int error;
1107
1108 error = kern_fstat(td, uap->fd, &ub);
1109 if (error == 0)
1110 error = copyout(&ub, uap->sb, sizeof(ub));
1111 return (error);
1112}
1113
1114int
1115kern_fstat(struct thread *td, int fd, struct stat *sbp)
1116{
1117 struct file *fp;
1118 int error;
1119
1120 AUDIT_ARG(fd, fd);
1121
1122 if ((error = fget(td, fd, &fp)) != 0)
1123 return (error);
1124
1125 AUDIT_ARG(file, td->td_proc, fp);
1126
1127 error = fo_stat(fp, sbp, td->td_ucred, td);
1128 fdrop(fp, td);
1129 return (error);
1130}
1131
1132/*
1133 * Return status information about a file descriptor.
1134 */
1135#ifndef _SYS_SYSPROTO_H_
1136struct nfstat_args {
1137 int fd;
1138 struct nstat *sb;
1139};
1140#endif
1141/* ARGSUSED */
1142int
1143nfstat(struct thread *td, struct nfstat_args *uap)
1144{
1145 struct nstat nub;
1146 struct stat ub;
1147 int error;
1148
1149 error = kern_fstat(td, uap->fd, &ub);
1150 if (error == 0) {
1151 cvtnstat(&ub, &nub);
1152 error = copyout(&nub, uap->sb, sizeof(nub));
1153 }
1154 return (error);
1155}
1156
1157/*
1158 * Return pathconf information about a file descriptor.
1159 */
1160#ifndef _SYS_SYSPROTO_H_
1161struct fpathconf_args {
1162 int fd;
1163 int name;
1164};
1165#endif
1166/* ARGSUSED */
1167int
1168fpathconf(struct thread *td, struct fpathconf_args *uap)
1169{
1170 struct file *fp;
1171 struct vnode *vp;
1172 int error;
1173
1174 if ((error = fget(td, uap->fd, &fp)) != 0)
1175 return (error);
1176
1177 /* If asynchronous I/O is available, it works for all descriptors. */
1178 if (uap->name == _PC_ASYNC_IO) {
1179 td->td_retval[0] = async_io_version;
1180 goto out;
1181 }
1182 vp = fp->f_vnode;
1183 if (vp != NULL) {
1184 int vfslocked;
1185 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
1186 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
1187 error = VOP_PATHCONF(vp, uap->name, td->td_retval);
1188 VOP_UNLOCK(vp, 0, td);
1189 VFS_UNLOCK_GIANT(vfslocked);
1190 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) {
1191 if (uap->name != _PC_PIPE_BUF) {
1192 error = EINVAL;
1193 } else {
1194 td->td_retval[0] = PIPE_BUF;
1195 error = 0;
1196 }
1197 } else {
1198 error = EOPNOTSUPP;
1199 }
1200out:
1201 fdrop(fp, td);
1202 return (error);
1203}
1204
1205/*
1206 * Grow the file table to accomodate (at least) nfd descriptors. This may
1207 * block and drop the filedesc lock, but it will reacquire it before
1208 * returning.
1209 */
1210static void
1211fdgrowtable(struct filedesc *fdp, int nfd)
1212{
1213 struct file **ntable;
1214 char *nfileflags;
1215 int nnfiles, onfiles;
1216 NDSLOTTYPE *nmap;
1217
1218 FILEDESC_XLOCK_ASSERT(fdp);
1219
1220 KASSERT(fdp->fd_nfiles > 0,
1221 ("zero-length file table"));
1222
1223 /* compute the size of the new table */
1224 onfiles = fdp->fd_nfiles;
1225 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */
1226 if (nnfiles <= onfiles)
1227 /* the table is already large enough */
1228 return;
1229
1230 /* allocate a new table and (if required) new bitmaps */
1231 FILEDESC_XUNLOCK(fdp);
1232 MALLOC(ntable, struct file **, nnfiles * OFILESIZE,
1233 M_FILEDESC, M_ZERO | M_WAITOK);
1234 nfileflags = (char *)&ntable[nnfiles];
1235 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles))
1236 MALLOC(nmap, NDSLOTTYPE *, NDSLOTS(nnfiles) * NDSLOTSIZE,
1237 M_FILEDESC, M_ZERO | M_WAITOK);
1238 else
1239 nmap = NULL;
1240 FILEDESC_XLOCK(fdp);
1241
1242 /*
1243 * We now have new tables ready to go. Since we dropped the
1244 * filedesc lock to call malloc(), watch out for a race.
1245 */
1246 onfiles = fdp->fd_nfiles;
1247 if (onfiles >= nnfiles) {
1248 /* we lost the race, but that's OK */
1249 free(ntable, M_FILEDESC);
1250 if (nmap != NULL)
1251 free(nmap, M_FILEDESC);
1252 return;
1253 }
1254 bcopy(fdp->fd_ofiles, ntable, onfiles * sizeof(*ntable));
1255 bcopy(fdp->fd_ofileflags, nfileflags, onfiles);
1256 if (onfiles > NDFILE)
1257 free(fdp->fd_ofiles, M_FILEDESC);
1258 fdp->fd_ofiles = ntable;
1259 fdp->fd_ofileflags = nfileflags;
1260 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) {
1261 bcopy(fdp->fd_map, nmap, NDSLOTS(onfiles) * sizeof(*nmap));
1262 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE))
1263 free(fdp->fd_map, M_FILEDESC);
1264 fdp->fd_map = nmap;
1265 }
1266 fdp->fd_nfiles = nnfiles;
1267}
1268
1269/*
1270 * Allocate a file descriptor for the process.
1271 */
1272int
1273fdalloc(struct thread *td, int minfd, int *result)
1274{
1275 struct proc *p = td->td_proc;
1276 struct filedesc *fdp = p->p_fd;
1277 int fd = -1, maxfd;
1278
1279 FILEDESC_XLOCK_ASSERT(fdp);
1280
1281 if (fdp->fd_freefile > minfd)
1282 minfd = fdp->fd_freefile;
1283
1284 PROC_LOCK(p);
1285 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
1286 PROC_UNLOCK(p);
1287
1288 /*
1289 * Search the bitmap for a free descriptor. If none is found, try
1290 * to grow the file table. Keep at it until we either get a file
1291 * descriptor or run into process or system limits; fdgrowtable()
1292 * may drop the filedesc lock, so we're in a race.
1293 */
1294 for (;;) {
1295 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles);
1296 if (fd >= maxfd)
1297 return (EMFILE);
1298 if (fd < fdp->fd_nfiles)
1299 break;
1300 fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd));
1301 }
1302
1303 /*
1304 * Perform some sanity checks, then mark the file descriptor as
1305 * used and return it to the caller.
1306 */
1307 KASSERT(!fdisused(fdp, fd),
1308 ("fd_first_free() returned non-free descriptor"));
1309 KASSERT(fdp->fd_ofiles[fd] == NULL,
1310 ("free descriptor isn't"));
1311 fdp->fd_ofileflags[fd] = 0; /* XXX needed? */
1312 fdused(fdp, fd);
1313 *result = fd;
1314 return (0);
1315}
1316
1317/*
1318 * Check to see whether n user file descriptors are available to the process
1319 * p.
1320 */
1321int
1322fdavail(struct thread *td, int n)
1323{
1324 struct proc *p = td->td_proc;
1325 struct filedesc *fdp = td->td_proc->p_fd;
1326 struct file **fpp;
1327 int i, lim, last;
1328
1329 FILEDESC_LOCK_ASSERT(fdp);
1330
1331 PROC_LOCK(p);
1332 lim = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
1333 PROC_UNLOCK(p);
1334 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
1335 return (1);
1336 last = min(fdp->fd_nfiles, lim);
1337 fpp = &fdp->fd_ofiles[fdp->fd_freefile];
1338 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) {
1339 if (*fpp == NULL && --n <= 0)
1340 return (1);
1341 }
1342 return (0);
1343}
1344
1345/*
1346 * Create a new open file structure and allocate a file decriptor for the
1347 * process that refers to it. We add one reference to the file for the
1348 * descriptor table and one reference for resultfp. This is to prevent us
1349 * being preempted and the entry in the descriptor table closed after we
1350 * release the FILEDESC lock.
1351 */
1352int
1353falloc(struct thread *td, struct file **resultfp, int *resultfd)
1354{
1355 struct proc *p = td->td_proc;
1356 struct file *fp;
1357 int error, i;
1358 int maxuserfiles = maxfiles - (maxfiles / 20);
1359 static struct timeval lastfail;
1360 static int curfail;
1361
1362 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO);
1363 if ((openfiles >= maxuserfiles &&
1364 priv_check(td, PRIV_MAXFILES) != 0) ||
1365 openfiles >= maxfiles) {
1366 if (ppsratecheck(&lastfail, &curfail, 1)) {
1367 printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n",
1368 td->td_ucred->cr_ruid);
1369 }
1370 uma_zfree(file_zone, fp);
1371 return (ENFILE);
1372 }
1373 atomic_add_int(&openfiles, 1);
1374
1375 /*
1376 * If the process has file descriptor zero open, add the new file
1377 * descriptor to the list of open files at that point, otherwise
1378 * put it at the front of the list of open files.
1379 */
1380 fp->f_count = 1;
1381 if (resultfp)
1382 fp->f_count++;
1383 fp->f_cred = crhold(td->td_ucred);
1384 fp->f_ops = &badfileops;
1385 fp->f_data = NULL;
1386 fp->f_vnode = NULL;
1387 FILEDESC_XLOCK(p->p_fd);
1388 if ((error = fdalloc(td, 0, &i))) {
1389 FILEDESC_XUNLOCK(p->p_fd);
1390 fdrop(fp, td);
1391 if (resultfp)
1392 fdrop(fp, td);
1393 return (error);
1394 }
1395 p->p_fd->fd_ofiles[i] = fp;
1396 FILEDESC_XUNLOCK(p->p_fd);
1397 if (resultfp)
1398 *resultfp = fp;
1399 if (resultfd)
1400 *resultfd = i;
1401 return (0);
1402}
1403
1404/*
1405 * Build a new filedesc structure from another.
1406 * Copy the current, root, and jail root vnode references.
1407 */
1408struct filedesc *
1409fdinit(struct filedesc *fdp)
1410{
1411 struct filedesc0 *newfdp;
1412
1413 newfdp = malloc(sizeof *newfdp, M_FILEDESC, M_WAITOK | M_ZERO);
1414 FILEDESC_LOCK_INIT(&newfdp->fd_fd);
1415 if (fdp != NULL) {
1416 FILEDESC_XLOCK(fdp);
1417 newfdp->fd_fd.fd_cdir = fdp->fd_cdir;
1418 if (newfdp->fd_fd.fd_cdir)
1419 VREF(newfdp->fd_fd.fd_cdir);
1420 newfdp->fd_fd.fd_rdir = fdp->fd_rdir;
1421 if (newfdp->fd_fd.fd_rdir)
1422 VREF(newfdp->fd_fd.fd_rdir);
1423 newfdp->fd_fd.fd_jdir = fdp->fd_jdir;
1424 if (newfdp->fd_fd.fd_jdir)
1425 VREF(newfdp->fd_fd.fd_jdir);
1426 FILEDESC_XUNLOCK(fdp);
1427 }
1428
1429 /* Create the file descriptor table. */
1430 newfdp->fd_fd.fd_refcnt = 1;
1431 newfdp->fd_fd.fd_holdcnt = 1;
1432 newfdp->fd_fd.fd_cmask = CMASK;
1433 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles;
1434 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags;
1435 newfdp->fd_fd.fd_nfiles = NDFILE;
1436 newfdp->fd_fd.fd_map = newfdp->fd_dmap;
1437 newfdp->fd_fd.fd_lastfile = -1;
1438 return (&newfdp->fd_fd);
1439}
1440
1441static struct filedesc *
1442fdhold(struct proc *p)
1443{
1444 struct filedesc *fdp;
1445
1446 mtx_lock(&fdesc_mtx);
1447 fdp = p->p_fd;
1448 if (fdp != NULL)
1449 fdp->fd_holdcnt++;
1450 mtx_unlock(&fdesc_mtx);
1451 return (fdp);
1452}
1453
1454static void
1455fddrop(struct filedesc *fdp)
1456{
1457 int i;
1458
1459 mtx_lock(&fdesc_mtx);
1460 i = --fdp->fd_holdcnt;
1461 mtx_unlock(&fdesc_mtx);
1462 if (i > 0)
1463 return;
1464
1465 FILEDESC_LOCK_DESTROY(fdp);
1466 FREE(fdp, M_FILEDESC);
1467}
1468
1469/*
1470 * Share a filedesc structure.
1471 */
1472struct filedesc *
1473fdshare(struct filedesc *fdp)
1474{
1475
1476 FILEDESC_XLOCK(fdp);
1477 fdp->fd_refcnt++;
1478 FILEDESC_XUNLOCK(fdp);
1479 return (fdp);
1480}
1481
1482/*
1483 * Unshare a filedesc structure, if necessary by making a copy
1484 */
1485void
1486fdunshare(struct proc *p, struct thread *td)
1487{
1488
1489 FILEDESC_XLOCK(p->p_fd);
1490 if (p->p_fd->fd_refcnt > 1) {
1491 struct filedesc *tmp;
1492
1493 FILEDESC_XUNLOCK(p->p_fd);
1494 tmp = fdcopy(p->p_fd);
1495 fdfree(td);
1496 p->p_fd = tmp;
1497 } else
1498 FILEDESC_XUNLOCK(p->p_fd);
1499}
1500
1501/*
1502 * Copy a filedesc structure. A NULL pointer in returns a NULL reference,
1503 * this is to ease callers, not catch errors.
1504 */
1505struct filedesc *
1506fdcopy(struct filedesc *fdp)
1507{
1508 struct filedesc *newfdp;
1509 int i;
1510
1511 /* Certain daemons might not have file descriptors. */
1512 if (fdp == NULL)
1513 return (NULL);
1514
1515 newfdp = fdinit(fdp);
1516 FILEDESC_SLOCK(fdp);
1517 while (fdp->fd_lastfile >= newfdp->fd_nfiles) {
1518 FILEDESC_SUNLOCK(fdp);
1519 FILEDESC_XLOCK(newfdp);
1520 fdgrowtable(newfdp, fdp->fd_lastfile + 1);
1521 FILEDESC_XUNLOCK(newfdp);
1522 FILEDESC_SLOCK(fdp);
1523 }
1524 /* copy everything except kqueue descriptors */
1525 newfdp->fd_freefile = -1;
1526 for (i = 0; i <= fdp->fd_lastfile; ++i) {
1527 if (fdisused(fdp, i) &&
1528 fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE) {
1529 newfdp->fd_ofiles[i] = fdp->fd_ofiles[i];
1530 newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i];
1531 fhold(newfdp->fd_ofiles[i]);
1532 newfdp->fd_lastfile = i;
1533 } else {
1534 if (newfdp->fd_freefile == -1)
1535 newfdp->fd_freefile = i;
1536 }
1537 }
1538 FILEDESC_SUNLOCK(fdp);
1539 FILEDESC_XLOCK(newfdp);
1540 for (i = 0; i <= newfdp->fd_lastfile; ++i)
1541 if (newfdp->fd_ofiles[i] != NULL)
1542 fdused(newfdp, i);
1543 FILEDESC_XUNLOCK(newfdp);
1544 FILEDESC_SLOCK(fdp);
1545 if (newfdp->fd_freefile == -1)
1546 newfdp->fd_freefile = i;
1547 newfdp->fd_cmask = fdp->fd_cmask;
1548 FILEDESC_SUNLOCK(fdp);
1549 return (newfdp);
1550}
1551
1552/*
1553 * Release a filedesc structure.
1554 */
1555void
1556fdfree(struct thread *td)
1557{
1558 struct filedesc *fdp;
1559 struct file **fpp;
1560 int i, locked;
1561 struct filedesc_to_leader *fdtol;
1562 struct file *fp;
1563 struct vnode *cdir, *jdir, *rdir, *vp;
1564 struct flock lf;
1565
1566 /* Certain daemons might not have file descriptors. */
1567 fdp = td->td_proc->p_fd;
1568 if (fdp == NULL)
1569 return;
1570
1571 /* Check for special need to clear POSIX style locks */
1572 fdtol = td->td_proc->p_fdtol;
1573 if (fdtol != NULL) {
1574 FILEDESC_XLOCK(fdp);
1575 KASSERT(fdtol->fdl_refcount > 0,
1576 ("filedesc_to_refcount botch: fdl_refcount=%d",
1577 fdtol->fdl_refcount));
1578 if (fdtol->fdl_refcount == 1 &&
1579 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
1580 for (i = 0, fpp = fdp->fd_ofiles;
1581 i <= fdp->fd_lastfile;
1582 i++, fpp++) {
1583 if (*fpp == NULL ||
1584 (*fpp)->f_type != DTYPE_VNODE)
1585 continue;
1586 fp = *fpp;
1587 fhold(fp);
1588 FILEDESC_XUNLOCK(fdp);
1589 lf.l_whence = SEEK_SET;
1590 lf.l_start = 0;
1591 lf.l_len = 0;
1592 lf.l_type = F_UNLCK;
1593 vp = fp->f_vnode;
1594 locked = VFS_LOCK_GIANT(vp->v_mount);
1595 (void) VOP_ADVLOCK(vp,
1596 (caddr_t)td->td_proc->
1597 p_leader,
1598 F_UNLCK,
1599 &lf,
1600 F_POSIX);
1601 VFS_UNLOCK_GIANT(locked);
1602 FILEDESC_XLOCK(fdp);
1603 fdrop(fp, td);
1604 fpp = fdp->fd_ofiles + i;
1605 }
1606 }
1607 retry:
1608 if (fdtol->fdl_refcount == 1) {
1609 if (fdp->fd_holdleaderscount > 0 &&
1610 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
1611 /*
1612 * close() or do_dup() has cleared a reference
1613 * in a shared file descriptor table.
1614 */
1615 fdp->fd_holdleaderswakeup = 1;
1616 sx_sleep(&fdp->fd_holdleaderscount,
1617 FILEDESC_LOCK(fdp), PLOCK, "fdlhold", 0);
1618 goto retry;
1619 }
1620 if (fdtol->fdl_holdcount > 0) {
1621 /*
1622 * Ensure that fdtol->fdl_leader remains
1623 * valid in closef().
1624 */
1625 fdtol->fdl_wakeup = 1;
1626 sx_sleep(fdtol, FILEDESC_LOCK(fdp), PLOCK,
1627 "fdlhold", 0);
1628 goto retry;
1629 }
1630 }
1631 fdtol->fdl_refcount--;
1632 if (fdtol->fdl_refcount == 0 &&
1633 fdtol->fdl_holdcount == 0) {
1634 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev;
1635 fdtol->fdl_prev->fdl_next = fdtol->fdl_next;
1636 } else
1637 fdtol = NULL;
1638 td->td_proc->p_fdtol = NULL;
1639 FILEDESC_XUNLOCK(fdp);
1640 if (fdtol != NULL)
1641 FREE(fdtol, M_FILEDESC_TO_LEADER);
1642 }
1643 FILEDESC_XLOCK(fdp);
1644 i = --fdp->fd_refcnt;
1645 FILEDESC_XUNLOCK(fdp);
1646 if (i > 0)
1647 return;
1648 /*
1649 * We are the last reference to the structure, so we can
1650 * safely assume it will not change out from under us.
1651 */
1652 fpp = fdp->fd_ofiles;
1653 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) {
1654 if (*fpp)
1655 (void) closef(*fpp, td);
1656 }
1657 FILEDESC_XLOCK(fdp);
1658
1659 /* XXX This should happen earlier. */
1660 mtx_lock(&fdesc_mtx);
1661 td->td_proc->p_fd = NULL;
1662 mtx_unlock(&fdesc_mtx);
1663
1664 if (fdp->fd_nfiles > NDFILE)
1665 FREE(fdp->fd_ofiles, M_FILEDESC);
1666 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE))
1667 FREE(fdp->fd_map, M_FILEDESC);
1668
1669 fdp->fd_nfiles = 0;
1670
1671 cdir = fdp->fd_cdir;
1672 fdp->fd_cdir = NULL;
1673 rdir = fdp->fd_rdir;
1674 fdp->fd_rdir = NULL;
1675 jdir = fdp->fd_jdir;
1676 fdp->fd_jdir = NULL;
1677 FILEDESC_XUNLOCK(fdp);
1678
1679 if (cdir) {
1680 locked = VFS_LOCK_GIANT(cdir->v_mount);
1681 vrele(cdir);
1682 VFS_UNLOCK_GIANT(locked);
1683 }
1684 if (rdir) {
1685 locked = VFS_LOCK_GIANT(rdir->v_mount);
1686 vrele(rdir);
1687 VFS_UNLOCK_GIANT(locked);
1688 }
1689 if (jdir) {
1690 locked = VFS_LOCK_GIANT(jdir->v_mount);
1691 vrele(jdir);
1692 VFS_UNLOCK_GIANT(locked);
1693 }
1694
1695 fddrop(fdp);
1696}
1697
1698/*
1699 * For setugid programs, we don't want to people to use that setugidness
1700 * to generate error messages which write to a file which otherwise would
1701 * otherwise be off-limits to the process. We check for filesystems where
1702 * the vnode can change out from under us after execve (like [lin]procfs).
1703 *
1704 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is
1705 * sufficient. We also don't check for setugidness since we know we are.
1706 */
1707static int
1708is_unsafe(struct file *fp)
1709{
1710 if (fp->f_type == DTYPE_VNODE) {
1711 struct vnode *vp = fp->f_vnode;
1712
1713 if ((vp->v_vflag & VV_PROCDEP) != 0)
1714 return (1);
1715 }
1716 return (0);
1717}
1718
1719/*
1720 * Make this setguid thing safe, if at all possible.
1721 */
1722void
1723setugidsafety(struct thread *td)
1724{
1725 struct filedesc *fdp;
1726 int i;
1727
1728 /* Certain daemons might not have file descriptors. */
1729 fdp = td->td_proc->p_fd;
1730 if (fdp == NULL)
1731 return;
1732
1733 /*
1734 * Note: fdp->fd_ofiles may be reallocated out from under us while
1735 * we are blocked in a close. Be careful!
1736 */
1737 FILEDESC_XLOCK(fdp);
1738 for (i = 0; i <= fdp->fd_lastfile; i++) {
1739 if (i > 2)
1740 break;
1741 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) {
1742 struct file *fp;
1743
1744 knote_fdclose(td, i);
1745 /*
1746 * NULL-out descriptor prior to close to avoid
1747 * a race while close blocks.
1748 */
1749 fp = fdp->fd_ofiles[i];
1750 fdp->fd_ofiles[i] = NULL;
1751 fdp->fd_ofileflags[i] = 0;
1752 fdunused(fdp, i);
1753 FILEDESC_XUNLOCK(fdp);
1754 (void) closef(fp, td);
1755 FILEDESC_XLOCK(fdp);
1756 }
1757 }
1758 FILEDESC_XUNLOCK(fdp);
1759}
1760
1761/*
1762 * If a specific file object occupies a specific file descriptor, close the
1763 * file descriptor entry and drop a reference on the file object. This is a
1764 * convenience function to handle a subsequent error in a function that calls
1765 * falloc() that handles the race that another thread might have closed the
1766 * file descriptor out from under the thread creating the file object.
1767 */
1768void
1769fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td)
1770{
1771
1772 FILEDESC_XLOCK(fdp);
1773 if (fdp->fd_ofiles[idx] == fp) {
1774 fdp->fd_ofiles[idx] = NULL;
1775 fdunused(fdp, idx);
1776 FILEDESC_XUNLOCK(fdp);
1777 fdrop(fp, td);
1778 } else
1779 FILEDESC_XUNLOCK(fdp);
1780}
1781
1782/*
1783 * Close any files on exec?
1784 */
1785void
1786fdcloseexec(struct thread *td)
1787{
1788 struct filedesc *fdp;
1789 int i;
1790
1791 /* Certain daemons might not have file descriptors. */
1792 fdp = td->td_proc->p_fd;
1793 if (fdp == NULL)
1794 return;
1795
1796 FILEDESC_XLOCK(fdp);
1797
1798 /*
1799 * We cannot cache fd_ofiles or fd_ofileflags since operations
1800 * may block and rip them out from under us.
1801 */
1802 for (i = 0; i <= fdp->fd_lastfile; i++) {
1803 if (fdp->fd_ofiles[i] != NULL &&
1804 (fdp->fd_ofiles[i]->f_type == DTYPE_MQUEUE ||
1805 (fdp->fd_ofileflags[i] & UF_EXCLOSE))) {
1806 struct file *fp;
1807
1808 knote_fdclose(td, i);
1809 /*
1810 * NULL-out descriptor prior to close to avoid
1811 * a race while close blocks.
1812 */
1813 fp = fdp->fd_ofiles[i];
1814 fdp->fd_ofiles[i] = NULL;
1815 fdp->fd_ofileflags[i] = 0;
1816 fdunused(fdp, i);
1817 if (fp->f_type == DTYPE_MQUEUE)
1818 mq_fdclose(td, i, fp);
1819 FILEDESC_XUNLOCK(fdp);
1820 (void) closef(fp, td);
1821 FILEDESC_XLOCK(fdp);
1822 }
1823 }
1824 FILEDESC_XUNLOCK(fdp);
1825}
1826
1827/*
1828 * It is unsafe for set[ug]id processes to be started with file
1829 * descriptors 0..2 closed, as these descriptors are given implicit
1830 * significance in the Standard C library. fdcheckstd() will create a
1831 * descriptor referencing /dev/null for each of stdin, stdout, and
1832 * stderr that is not already open.
1833 */
1834int
1835fdcheckstd(struct thread *td)
1836{
1837 struct filedesc *fdp;
1838 register_t retval, save;
1839 int i, error, devnull;
1840
1841 fdp = td->td_proc->p_fd;
1842 if (fdp == NULL)
1843 return (0);
1844 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared"));
1845 devnull = -1;
1846 error = 0;
1847 for (i = 0; i < 3; i++) {
1848 if (fdp->fd_ofiles[i] != NULL)
1849 continue;
1850 if (devnull < 0) {
1851 save = td->td_retval[0];
1852 error = kern_open(td, "/dev/null", UIO_SYSSPACE,
1853 O_RDWR, 0);
1854 devnull = td->td_retval[0];
1855 KASSERT(devnull == i, ("oof, we didn't get our fd"));
1856 td->td_retval[0] = save;
1857 if (error)
1858 break;
1859 } else {
1860 error = do_dup(td, DUP_FIXED, devnull, i, &retval);
1861 if (error != 0)
1862 break;
1863 }
1864 }
1865 return (error);
1866}
1867
1868/*
1869 * Internal form of close. Decrement reference count on file structure.
1870 * Note: td may be NULL when closing a file that was being passed in a
1871 * message.
1872 *
1873 * XXXRW: Giant is not required for the caller, but often will be held; this
1874 * makes it moderately likely the Giant will be recursed in the VFS case.
1875 */
1876int
1877closef(struct file *fp, struct thread *td)
1878{
1879 struct vnode *vp;
1880 struct flock lf;
1881 struct filedesc_to_leader *fdtol;
1882 struct filedesc *fdp;
1883
1884 /*
1885 * POSIX record locking dictates that any close releases ALL
1886 * locks owned by this process. This is handled by setting
1887 * a flag in the unlock to free ONLY locks obeying POSIX
1888 * semantics, and not to free BSD-style file locks.
1889 * If the descriptor was in a message, POSIX-style locks
1890 * aren't passed with the descriptor, and the thread pointer
1891 * will be NULL. Callers should be careful only to pass a
1892 * NULL thread pointer when there really is no owning
1893 * context that might have locks, or the locks will be
1894 * leaked.
1895 */
1896 if (fp->f_type == DTYPE_VNODE && td != NULL) {
1897 int vfslocked;
1898
1899 vp = fp->f_vnode;
1900 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
1901 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
1902 lf.l_whence = SEEK_SET;
1903 lf.l_start = 0;
1904 lf.l_len = 0;
1905 lf.l_type = F_UNLCK;
1906 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader,
1907 F_UNLCK, &lf, F_POSIX);
1908 }
1909 fdtol = td->td_proc->p_fdtol;
1910 if (fdtol != NULL) {
1911 /*
1912 * Handle special case where file descriptor table is
1913 * shared between multiple process leaders.
1914 */
1915 fdp = td->td_proc->p_fd;
1916 FILEDESC_XLOCK(fdp);
1917 for (fdtol = fdtol->fdl_next;
1918 fdtol != td->td_proc->p_fdtol;
1919 fdtol = fdtol->fdl_next) {
1920 if ((fdtol->fdl_leader->p_flag &
1921 P_ADVLOCK) == 0)
1922 continue;
1923 fdtol->fdl_holdcount++;
1924 FILEDESC_XUNLOCK(fdp);
1925 lf.l_whence = SEEK_SET;
1926 lf.l_start = 0;
1927 lf.l_len = 0;
1928 lf.l_type = F_UNLCK;
1929 vp = fp->f_vnode;
1930 (void) VOP_ADVLOCK(vp,
1931 (caddr_t)fdtol->fdl_leader,
1932 F_UNLCK, &lf, F_POSIX);
1933 FILEDESC_XLOCK(fdp);
1934 fdtol->fdl_holdcount--;
1935 if (fdtol->fdl_holdcount == 0 &&
1936 fdtol->fdl_wakeup != 0) {
1937 fdtol->fdl_wakeup = 0;
1938 wakeup(fdtol);
1939 }
1940 }
1941 FILEDESC_XUNLOCK(fdp);
1942 }
1943 VFS_UNLOCK_GIANT(vfslocked);
1944 }
1945 return (fdrop(fp, td));
1946}
1947
1948/*
1949 * Initialize the file pointer with the specified properties.
1950 *
1951 * The ops are set with release semantics to be certain that the flags, type,
1952 * and data are visible when ops is. This is to prevent ops methods from being
1953 * called with bad data.
1954 */
1955void
1956finit(struct file *fp, u_int flag, short type, void *data, struct fileops *ops)
1957{
1958 fp->f_data = data;
1959 fp->f_flag = flag;
1960 fp->f_type = type;
1961 atomic_store_rel_ptr((volatile uintptr_t *)&fp->f_ops, (uintptr_t)ops);
1962}
1963
1964
1965/*
1966 * Extract the file pointer associated with the specified descriptor for the
1967 * current user process.
1968 *
1969 * If the descriptor doesn't exist, EBADF is returned.
1970 *
1971 * If the descriptor exists but doesn't match 'flags' then return EBADF for
1972 * read attempts and EINVAL for write attempts.
1973 *
1974 * If 'hold' is set (non-zero) the file's refcount will be bumped on return.
1975 * It should be dropped with fdrop(). If it is not set, then the refcount
1976 * will not be bumped however the thread's filedesc struct will be returned
1977 * locked (for fgetsock).
1978 *
1979 * If an error occured the non-zero error is returned and *fpp is set to
1980 * NULL. Otherwise *fpp is set and zero is returned.
1981 */
1982static __inline int
1983_fget(struct thread *td, int fd, struct file **fpp, int flags, int hold)
1984{
1985 struct filedesc *fdp;
1986 struct file *fp;
1987
1988 *fpp = NULL;
1989 if (td == NULL || (fdp = td->td_proc->p_fd) == NULL)
1990 return (EBADF);
1991 FILEDESC_SLOCK(fdp);
1992 if ((fp = fget_locked(fdp, fd)) == NULL || fp->f_ops == &badfileops) {
1993 FILEDESC_SUNLOCK(fdp);
1994 return (EBADF);
1995 }
1996
1997 /*
1998 * FREAD and FWRITE failure return EBADF as per POSIX.
1999 *
2000 * Only one flag, or 0, may be specified.
2001 */
2002 if (flags == FREAD && (fp->f_flag & FREAD) == 0) {
2003 FILEDESC_SUNLOCK(fdp);
2004 return (EBADF);
2005 }
2006 if (flags == FWRITE && (fp->f_flag & FWRITE) == 0) {
2007 FILEDESC_SUNLOCK(fdp);
2008 return (EBADF);
2009 }
2010 if (hold) {
2011 fhold(fp);
2012 FILEDESC_SUNLOCK(fdp);
2013 }
2014 *fpp = fp;
2015 return (0);
2016}
2017
2018int
2019fget(struct thread *td, int fd, struct file **fpp)
2020{
2021
2022 return(_fget(td, fd, fpp, 0, 1));
2023}
2024
2025int
2026fget_read(struct thread *td, int fd, struct file **fpp)
2027{
2028
2029 return(_fget(td, fd, fpp, FREAD, 1));
2030}
2031
2032int
2033fget_write(struct thread *td, int fd, struct file **fpp)
2034{
2035
2036 return(_fget(td, fd, fpp, FWRITE, 1));
2037}
2038
2039/*
2040 * Like fget() but loads the underlying vnode, or returns an error if the
2041 * descriptor does not represent a vnode. Note that pipes use vnodes but
2042 * never have VM objects. The returned vnode will be vref()'d.
2043 *
2044 * XXX: what about the unused flags ?
2045 */
2046static __inline int
2047_fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags)
2048{
2049 struct file *fp;
2050 int error;
2051
2052 *vpp = NULL;
2053 if ((error = _fget(td, fd, &fp, 0, 0)) != 0)
2054 return (error);
2055 if (fp->f_vnode == NULL) {
2056 error = EINVAL;
2057 } else {
2058 *vpp = fp->f_vnode;
2059 vref(*vpp);
2060 }
2061 FILEDESC_SUNLOCK(td->td_proc->p_fd);
2062 return (error);
2063}
2064
2065int
2066fgetvp(struct thread *td, int fd, struct vnode **vpp)
2067{
2068
2069 return (_fgetvp(td, fd, vpp, 0));
2070}
2071
2072int
2073fgetvp_read(struct thread *td, int fd, struct vnode **vpp)
2074{
2075
2076 return (_fgetvp(td, fd, vpp, FREAD));
2077}
2078
2079#ifdef notyet
2080int
2081fgetvp_write(struct thread *td, int fd, struct vnode **vpp)
2082{
2083
2084 return (_fgetvp(td, fd, vpp, FWRITE));
2085}
2086#endif
2087
2088/*
2089 * Like fget() but loads the underlying socket, or returns an error if the
2090 * descriptor does not represent a socket.
2091 *
2092 * We bump the ref count on the returned socket. XXX Also obtain the SX lock
2093 * in the future.
2094 *
2095 * XXXRW: fgetsock() and fputsock() are deprecated, as consumers should rely
2096 * on their file descriptor reference to prevent the socket from being free'd
2097 * during use.
2098 */
2099int
2100fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp)
2101{
2102 struct file *fp;
2103 int error;
2104
2105 *spp = NULL;
2106 if (fflagp != NULL)
2107 *fflagp = 0;
2108 if ((error = _fget(td, fd, &fp, 0, 0)) != 0)
2109 return (error);
2110 if (fp->f_type != DTYPE_SOCKET) {
2111 error = ENOTSOCK;
2112 } else {
2113 *spp = fp->f_data;
2114 if (fflagp)
2115 *fflagp = fp->f_flag;
2116 SOCK_LOCK(*spp);
2117 soref(*spp);
2118 SOCK_UNLOCK(*spp);
2119 }
2120 FILEDESC_SUNLOCK(td->td_proc->p_fd);
2121 return (error);
2122}
2123
2124/*
2125 * Drop the reference count on the socket and XXX release the SX lock in the
2126 * future. The last reference closes the socket.
2127 *
2128 * XXXRW: fputsock() is deprecated, see comment for fgetsock().
2129 */
2130void
2131fputsock(struct socket *so)
2132{
2133
2134 ACCEPT_LOCK();
2135 SOCK_LOCK(so);
2136 sorele(so);
2137}
2138
2139/*
2140 * Handle the last reference to a file being closed.
2141 */
2142int
2143_fdrop(struct file *fp, struct thread *td)
2144{
2145 int error;
2146
2147 error = 0;
2148 if (fp->f_count != 0)
2149 panic("fdrop: count %d", fp->f_count);
2150 if (fp->f_ops != &badfileops)
2151 error = fo_close(fp, td);
2152 atomic_subtract_int(&openfiles, 1);
2153 crfree(fp->f_cred);
2154 uma_zfree(file_zone, fp);
2155
2156 return (error);
2157}
2158
2159/*
2160 * Apply an advisory lock on a file descriptor.
2161 *
2162 * Just attempt to get a record lock of the requested type on the entire file
2163 * (l_whence = SEEK_SET, l_start = 0, l_len = 0).
2164 */
2165#ifndef _SYS_SYSPROTO_H_
2166struct flock_args {
2167 int fd;
2168 int how;
2169};
2170#endif
2171/* ARGSUSED */
2172int
2173flock(struct thread *td, struct flock_args *uap)
2174{
2175 struct file *fp;
2176 struct vnode *vp;
2177 struct flock lf;
2178 int vfslocked;
2179 int error;
2180
2181 if ((error = fget(td, uap->fd, &fp)) != 0)
2182 return (error);
2183 if (fp->f_type != DTYPE_VNODE) {
2184 fdrop(fp, td);
2185 return (EOPNOTSUPP);
2186 }
2187
2188 vp = fp->f_vnode;
2189 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
2190 lf.l_whence = SEEK_SET;
2191 lf.l_start = 0;
2192 lf.l_len = 0;
2193 if (uap->how & LOCK_UN) {
2194 lf.l_type = F_UNLCK;
2195 atomic_clear_int(&fp->f_flag, FHASLOCK);
2196 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
2197 goto done2;
2198 }
2199 if (uap->how & LOCK_EX)
2200 lf.l_type = F_WRLCK;
2201 else if (uap->how & LOCK_SH)
2202 lf.l_type = F_RDLCK;
2203 else {
2204 error = EBADF;
2205 goto done2;
2206 }
2207 atomic_set_int(&fp->f_flag, FHASLOCK);
2208 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf,
2209 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT);
2210done2:
2211 fdrop(fp, td);
2212 VFS_UNLOCK_GIANT(vfslocked);
2213 return (error);
2214}
2215/*
2216 * Duplicate the specified descriptor to a free descriptor.
2217 */
2218int
2219dupfdopen(struct thread *td, struct filedesc *fdp, int indx, int dfd, int mode, int error)
2220{
2221 struct file *wfp;
2222 struct file *fp;
2223
2224 /*
2225 * If the to-be-dup'd fd number is greater than the allowed number
2226 * of file descriptors, or the fd to be dup'd has already been
2227 * closed, then reject.
2228 */
2229 FILEDESC_XLOCK(fdp);
2230 if (dfd < 0 || dfd >= fdp->fd_nfiles ||
2231 (wfp = fdp->fd_ofiles[dfd]) == NULL) {
2232 FILEDESC_XUNLOCK(fdp);
2233 return (EBADF);
2234 }
2235
2236 /*
2237 * There are two cases of interest here.
2238 *
2239 * For ENODEV simply dup (dfd) to file descriptor (indx) and return.
2240 *
2241 * For ENXIO steal away the file structure from (dfd) and store it in
2242 * (indx). (dfd) is effectively closed by this operation.
2243 *
2244 * Any other error code is just returned.
2245 */
2246 switch (error) {
2247 case ENODEV:
2248 /*
2249 * Check that the mode the file is being opened for is a
2250 * subset of the mode of the existing descriptor.
2251 */
2252 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) {
2253 FILEDESC_XUNLOCK(fdp);
2254 return (EACCES);
2255 }
2256 fp = fdp->fd_ofiles[indx];
2257 fdp->fd_ofiles[indx] = wfp;
2258 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
2259 if (fp == NULL)
2260 fdused(fdp, indx);
2261 fhold(wfp);
2262 FILEDESC_XUNLOCK(fdp);
2263 if (fp != NULL)
2264 /*
2265 * We now own the reference to fp that the ofiles[]
2266 * array used to own. Release it.
2267 */
2268 fdrop(fp, td);
2269 return (0);
2270
2271 case ENXIO:
2272 /*
2273 * Steal away the file pointer from dfd and stuff it into indx.
2274 */
2275 fp = fdp->fd_ofiles[indx];
2276 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd];
2277 fdp->fd_ofiles[dfd] = NULL;
2278 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
2279 fdp->fd_ofileflags[dfd] = 0;
2280 fdunused(fdp, dfd);
2281 if (fp == NULL)
2282 fdused(fdp, indx);
2283 FILEDESC_XUNLOCK(fdp);
2284
2285 /*
2286 * We now own the reference to fp that the ofiles[] array
2287 * used to own. Release it.
2288 */
2289 if (fp != NULL)
2290 fdrop(fp, td);
2291 return (0);
2292
2293 default:
2294 FILEDESC_XUNLOCK(fdp);
2295 return (error);
2296 }
2297 /* NOTREACHED */
2298}
2299
2300/*
2301 * Scan all active processes to see if any of them have a current or root
2302 * directory of `olddp'. If so, replace them with the new mount point.
2303 */
2304void
2305mountcheckdirs(struct vnode *olddp, struct vnode *newdp)
2306{
2307 struct filedesc *fdp;
2308 struct proc *p;
2309 int nrele;
2310
2311 if (vrefcnt(olddp) == 1)
2312 return;
2313 sx_slock(&allproc_lock);
2314 FOREACH_PROC_IN_SYSTEM(p) {
2315 fdp = fdhold(p);
2316 if (fdp == NULL)
2317 continue;
2318 nrele = 0;
2319 FILEDESC_XLOCK(fdp);
2320 if (fdp->fd_cdir == olddp) {
2321 vref(newdp);
2322 fdp->fd_cdir = newdp;
2323 nrele++;
2324 }
2325 if (fdp->fd_rdir == olddp) {
2326 vref(newdp);
2327 fdp->fd_rdir = newdp;
2328 nrele++;
2329 }
2330 FILEDESC_XUNLOCK(fdp);
2331 fddrop(fdp);
2332 while (nrele--)
2333 vrele(olddp);
2334 }
2335 sx_sunlock(&allproc_lock);
2336 if (rootvnode == olddp) {
2337 vrele(rootvnode);
2338 vref(newdp);
2339 rootvnode = newdp;
2340 }
2341}
2342
2343struct filedesc_to_leader *
2344filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader)
2345{
2346 struct filedesc_to_leader *fdtol;
2347
2348 MALLOC(fdtol, struct filedesc_to_leader *,
2349 sizeof(struct filedesc_to_leader),
2350 M_FILEDESC_TO_LEADER,
2351 M_WAITOK);
2352 fdtol->fdl_refcount = 1;
2353 fdtol->fdl_holdcount = 0;
2354 fdtol->fdl_wakeup = 0;
2355 fdtol->fdl_leader = leader;
2356 if (old != NULL) {
2357 FILEDESC_XLOCK(fdp);
2358 fdtol->fdl_next = old->fdl_next;
2359 fdtol->fdl_prev = old;
2360 old->fdl_next = fdtol;
2361 fdtol->fdl_next->fdl_prev = fdtol;
2362 FILEDESC_XUNLOCK(fdp);
2363 } else {
2364 fdtol->fdl_next = fdtol;
2365 fdtol->fdl_prev = fdtol;
2366 }
2367 return (fdtol);
2368}
2369
2370/*
2371 * Get file structures globally.
2372 */
2373static int
2374sysctl_kern_file(SYSCTL_HANDLER_ARGS)
2375{
2376 struct xfile xf;
2377 struct filedesc *fdp;
2378 struct file *fp;
2379 struct proc *p;
2380 int error, n;
2381
2382 error = sysctl_wire_old_buffer(req, 0);
2383 if (error != 0)
2384 return (error);
2385 if (req->oldptr == NULL) {
2386 n = 0;
2387 sx_slock(&allproc_lock);
2388 FOREACH_PROC_IN_SYSTEM(p) {
2389 if (p->p_state == PRS_NEW)
2390 continue;
2391 fdp = fdhold(p);
2392 if (fdp == NULL)
2393 continue;
2394 /* overestimates sparse tables. */
2395 if (fdp->fd_lastfile > 0)
2396 n += fdp->fd_lastfile;
2397 fddrop(fdp);
2398 }
2399 sx_sunlock(&allproc_lock);
2400 return (SYSCTL_OUT(req, 0, n * sizeof(xf)));
2401 }
2402 error = 0;
2403 bzero(&xf, sizeof(xf));
2404 xf.xf_size = sizeof(xf);
2405 sx_slock(&allproc_lock);
2406 FOREACH_PROC_IN_SYSTEM(p) {
2407 if (p->p_state == PRS_NEW)
2408 continue;
2409 PROC_LOCK(p);
2410 if (p_cansee(req->td, p) != 0) {
2411 PROC_UNLOCK(p);
2412 continue;
2413 }
2414 xf.xf_pid = p->p_pid;
2415 xf.xf_uid = p->p_ucred->cr_uid;
2416 PROC_UNLOCK(p);
2417 fdp = fdhold(p);
2418 if (fdp == NULL)
2419 continue;
2420 FILEDESC_SLOCK(fdp);
2421 for (n = 0; fdp->fd_refcnt > 0 && n < fdp->fd_nfiles; ++n) {
2422 if ((fp = fdp->fd_ofiles[n]) == NULL)
2423 continue;
2424 xf.xf_fd = n;
2425 xf.xf_file = fp;
2426 xf.xf_data = fp->f_data;
2427 xf.xf_vnode = fp->f_vnode;
2428 xf.xf_type = fp->f_type;
2429 xf.xf_count = fp->f_count;
2430 xf.xf_msgcount = 0;
2431 xf.xf_offset = fp->f_offset;
2432 xf.xf_flag = fp->f_flag;
2433 error = SYSCTL_OUT(req, &xf, sizeof(xf));
2434 if (error)
2435 break;
2436 }
2437 FILEDESC_SUNLOCK(fdp);
2438 fddrop(fdp);
2439 if (error)
2440 break;
2441 }
2442 sx_sunlock(&allproc_lock);
2443 return (error);
2444}
2445
2446SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD,
2447 0, 0, sysctl_kern_file, "S,xfile", "Entire file table");
2448
2449/*
2450 * Get per-process file descriptors for use by procstat(1), et al.
2451 */
2452static int
2453sysctl_kern_proc_filedesc(SYSCTL_HANDLER_ARGS)
2454{
2455 char *fullpath, *freepath;
2456 struct kinfo_file *kif;
2457 struct filedesc *fdp;
2458 int error, i, *name;
2459 struct socket *so;
2460 struct vnode *vp;
2461 struct file *fp;
2462 struct proc *p;
2463 int vfslocked;
2464
2465 name = (int *)arg1;
2466 if ((p = pfind((pid_t)name[0])) == NULL)
2467 return (ESRCH);
2468 if ((error = p_candebug(curthread, p))) {
2469 PROC_UNLOCK(p);
2470 return (error);
2471 }
2472 fdp = fdhold(p);
2473 PROC_UNLOCK(p);
2474 kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK);
2475 FILEDESC_SLOCK(fdp);
2476 for (i = 0; i < fdp->fd_nfiles; i++) {
2477 if ((fp = fdp->fd_ofiles[i]) == NULL)
2478 continue;
2479 bzero(kif, sizeof(*kif));
2480 kif->kf_structsize = sizeof(*kif);
2481 vp = NULL;
2482 so = NULL;
2483 kif->kf_fd = i;
2484 switch (fp->f_type) {
2485 case DTYPE_VNODE:
2486 kif->kf_type = KF_TYPE_VNODE;
2487 vp = fp->f_vnode;
2488 break;
2489
2490 case DTYPE_SOCKET:
2491 kif->kf_type = KF_TYPE_SOCKET;
2492 so = fp->f_data;
2493 break;
2494
2495 case DTYPE_PIPE:
2496 kif->kf_type = KF_TYPE_PIPE;
2497 break;
2498
2499 case DTYPE_FIFO:
2500 kif->kf_type = KF_TYPE_FIFO;
2501 vp = fp->f_vnode;
2502 vref(vp);
2503 break;
2504
2505 case DTYPE_KQUEUE:
2506 kif->kf_type = KF_TYPE_KQUEUE;
2507 break;
2508
2509 case DTYPE_CRYPTO:
2510 kif->kf_type = KF_TYPE_CRYPTO;
2511 break;
2512
2513 case DTYPE_MQUEUE:
2514 kif->kf_type = KF_TYPE_MQUEUE;
2515 break;
2516
2517 default:
2518 kif->kf_type = KF_TYPE_UNKNOWN;
2519 break;
2520 }
2521 kif->kf_ref_count = fp->f_count;
2522 if (fp->f_flag & FREAD)
2523 kif->kf_flags |= KF_FLAG_READ;
2524 if (fp->f_flag & FWRITE)
2525 kif->kf_flags |= KF_FLAG_WRITE;
2526 if (fp->f_flag & FAPPEND)
2527 kif->kf_flags |= KF_FLAG_APPEND;
2528 if (fp->f_flag & FASYNC)
2529 kif->kf_flags |= KF_FLAG_ASYNC;
2530 if (fp->f_flag & FFSYNC)
2531 kif->kf_flags |= KF_FLAG_FSYNC;
2532 if (fp->f_flag & FNONBLOCK)
2533 kif->kf_flags |= KF_FLAG_NONBLOCK;
2534 if (fp->f_flag & O_DIRECT)
2535 kif->kf_flags |= KF_FLAG_DIRECT;
2536 if (fp->f_flag & FHASLOCK)
2537 kif->kf_flags |= KF_FLAG_HASLOCK;
2538 kif->kf_offset = fp->f_offset;
2539 if (vp != NULL) {
2540 vref(vp);
2541 switch (vp->v_type) {
2542 case VNON:
2543 kif->kf_vnode_type = KF_VTYPE_VNON;
2544 break;
2545 case VREG:
2546 kif->kf_vnode_type = KF_VTYPE_VREG;
2547 break;
2548 case VDIR:
2549 kif->kf_vnode_type = KF_VTYPE_VDIR;
2550 break;
2551 case VBLK:
2552 kif->kf_vnode_type = KF_VTYPE_VBLK;
2553 break;
2554 case VCHR:
2555 kif->kf_vnode_type = KF_VTYPE_VCHR;
2556 break;
2557 case VLNK:
2558 kif->kf_vnode_type = KF_VTYPE_VLNK;
2559 break;
2560 case VSOCK:
2561 kif->kf_vnode_type = KF_VTYPE_VSOCK;
2562 break;
2563 case VFIFO:
2564 kif->kf_vnode_type = KF_VTYPE_VFIFO;
2565 break;
2566 case VBAD:
2567 kif->kf_vnode_type = KF_VTYPE_VBAD;
2568 break;
2569 default:
2570 kif->kf_vnode_type = KF_VTYPE_UNKNOWN;
2571 break;
2572 }
2573 /*
2574 * It is OK to drop the filedesc lock here as we will
2575 * re-validate and re-evaluate its properties when
2576 * the loop continues.
2577 */
2578 freepath = NULL;
2579 fullpath = "-";
2580 FILEDESC_SUNLOCK(fdp);
2581 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
2582 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, curthread);
2583 vn_fullpath(curthread, vp, &fullpath, &freepath);
2584 vput(vp);
2585 VFS_UNLOCK_GIANT(vfslocked);
2586 strlcpy(kif->kf_path, fullpath,
2587 sizeof(kif->kf_path));
2588 if (freepath != NULL)
2589 free(freepath, M_TEMP);
2590 FILEDESC_SLOCK(fdp);
2591 }
2592 if (so != NULL) {
2593 struct sockaddr *sa;
2594
2595 if (so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa)
2596 == 0 && sa->sa_len <= sizeof(kif->kf_sa_local)) {
2597 bcopy(sa, &kif->kf_sa_local, sa->sa_len);
2598 free(sa, M_SONAME);
2599 }
2600 if (so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa)
2601 == 00 && sa->sa_len <= sizeof(kif->kf_sa_peer)) {
2602 bcopy(sa, &kif->kf_sa_peer, sa->sa_len);
2603 free(sa, M_SONAME);
2604 }
2605 kif->kf_sock_domain =
2606 so->so_proto->pr_domain->dom_family;
2607 kif->kf_sock_type = so->so_type;
2608 kif->kf_sock_protocol = so->so_proto->pr_protocol;
2609 }
2610 error = SYSCTL_OUT(req, kif, sizeof(*kif));
2611 if (error)
2612 break;
2613 }
2614 FILEDESC_SUNLOCK(fdp);
2615 fddrop(fdp);
2616 free(kif, M_TEMP);
2617 return (0);
2618}
2619
2620static SYSCTL_NODE(_kern_proc, KERN_PROC_FILEDESC, filedesc, CTLFLAG_RD,
2621 sysctl_kern_proc_filedesc, "Process filedesc entries");
2622
2623#ifdef DDB
2624/*
2625 * For the purposes of debugging, generate a human-readable string for the
2626 * file type.
2627 */
2628static const char *
2629file_type_to_name(short type)
2630{
2631
2632 switch (type) {
2633 case 0:
2634 return ("zero");
2635 case DTYPE_VNODE:
2636 return ("vnod");
2637 case DTYPE_SOCKET:
2638 return ("sock");
2639 case DTYPE_PIPE:
2640 return ("pipe");
2641 case DTYPE_FIFO:
2642 return ("fifo");
2643 case DTYPE_KQUEUE:
2644 return ("kque");
2645 case DTYPE_CRYPTO:
2646 return ("crpt");
2647 case DTYPE_MQUEUE:
2648 return ("mque");
|
2649 default:
2650 return ("unkn");
2651 }
2652}
2653
2654/*
2655 * For the purposes of debugging, identify a process (if any, perhaps one of
2656 * many) that references the passed file in its file descriptor array. Return
2657 * NULL if none.
2658 */
2659static struct proc *
2660file_to_first_proc(struct file *fp)
2661{
2662 struct filedesc *fdp;
2663 struct proc *p;
2664 int n;
2665
2666 FOREACH_PROC_IN_SYSTEM(p) {
2667 if (p->p_state == PRS_NEW)
2668 continue;
2669 fdp = p->p_fd;
2670 if (fdp == NULL)
2671 continue;
2672 for (n = 0; n < fdp->fd_nfiles; n++) {
2673 if (fp == fdp->fd_ofiles[n])
2674 return (p);
2675 }
2676 }
2677 return (NULL);
2678}
2679
2680static void
2681db_print_file(struct file *fp, int header)
2682{
2683 struct proc *p;
2684
2685 if (header)
2686 db_printf("%8s %4s %8s %8s %4s %5s %6s %8s %5s %12s\n",
2687 "File", "Type", "Data", "Flag", "GCFl", "Count",
2688 "MCount", "Vnode", "FPID", "FCmd");
2689 p = file_to_first_proc(fp);
2690 db_printf("%8p %4s %8p %08x %04x %5d %6d %8p %5d %12s\n", fp,
2691 file_type_to_name(fp->f_type), fp->f_data, fp->f_flag,
2692 0, fp->f_count, 0, fp->f_vnode,
2693 p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-");
2694}
2695
2696DB_SHOW_COMMAND(file, db_show_file)
2697{
2698 struct file *fp;
2699
2700 if (!have_addr) {
2701 db_printf("usage: show file <addr>\n");
2702 return;
2703 }
2704 fp = (struct file *)addr;
2705 db_print_file(fp, 1);
2706}
2707
2708DB_SHOW_COMMAND(files, db_show_files)
2709{
2710 struct filedesc *fdp;
2711 struct file *fp;
2712 struct proc *p;
2713 int header;
2714 int n;
2715
2716 header = 1;
2717 FOREACH_PROC_IN_SYSTEM(p) {
2718 if (p->p_state == PRS_NEW)
2719 continue;
2720 if ((fdp = p->p_fd) == NULL)
2721 continue;
2722 for (n = 0; n < fdp->fd_nfiles; ++n) {
2723 if ((fp = fdp->fd_ofiles[n]) == NULL)
2724 continue;
2725 db_print_file(fp, header);
2726 header = 0;
2727 }
2728 }
2729}
2730#endif
2731
2732SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW,
2733 &maxfilesperproc, 0, "Maximum files allowed open per process");
2734
2735SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW,
2736 &maxfiles, 0, "Maximum number of files");
2737
2738SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD,
2739 __DEVOLATILE(int *, &openfiles), 0, "System-wide number of open files");
2740
2741/* ARGSUSED*/
2742static void
2743filelistinit(void *dummy)
2744{
2745
2746 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL,
2747 NULL, NULL, UMA_ALIGN_PTR, 0);
2748 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF);
2749 mtx_init(&fdesc_mtx, "fdesc", NULL, MTX_DEF);
2750}
2751SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL)
2752
2753/*-------------------------------------------------------------------*/
2754
2755static int
2756badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td)
2757{
2758
2759 return (EBADF);
2760}
2761
2762static int
2763badfo_truncate(struct file *fp, off_t length, struct ucred *active_cred, struct thread *td)
2764{
2765
2766 return (EINVAL);
2767}
2768
2769static int
2770badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, struct thread *td)
2771{
2772
2773 return (EBADF);
2774}
2775
2776static int
2777badfo_poll(struct file *fp, int events, struct ucred *active_cred, struct thread *td)
2778{
2779
2780 return (0);
2781}
2782
2783static int
2784badfo_kqfilter(struct file *fp, struct knote *kn)
2785{
2786
2787 return (EBADF);
2788}
2789
2790static int
2791badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, struct thread *td)
2792{
2793
2794 return (EBADF);
2795}
2796
2797static int
2798badfo_close(struct file *fp, struct thread *td)
2799{
2800
2801 return (EBADF);
2802}
2803
2804struct fileops badfileops = {
2805 .fo_read = badfo_readwrite,
2806 .fo_write = badfo_readwrite,
2807 .fo_truncate = badfo_truncate,
2808 .fo_ioctl = badfo_ioctl,
2809 .fo_poll = badfo_poll,
2810 .fo_kqfilter = badfo_kqfilter,
2811 .fo_stat = badfo_stat,
2812 .fo_close = badfo_close,
2813};
2814
2815
2816/*-------------------------------------------------------------------*/
2817
2818/*
2819 * File Descriptor pseudo-device driver (/dev/fd/).
2820 *
2821 * Opening minor device N dup()s the file (if any) connected to file
2822 * descriptor N belonging to the calling process. Note that this driver
2823 * consists of only the ``open()'' routine, because all subsequent
2824 * references to this file will be direct to the other driver.
2825 *
2826 * XXX: we could give this one a cloning event handler if necessary.
2827 */
2828
2829/* ARGSUSED */
2830static int
2831fdopen(struct cdev *dev, int mode, int type, struct thread *td)
2832{
2833
2834 /*
2835 * XXX Kludge: set curthread->td_dupfd to contain the value of the
2836 * the file descriptor being sought for duplication. The error
2837 * return ensures that the vnode for this device will be released
2838 * by vn_open. Open will detect this special error and take the
2839 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
2840 * will simply report the error.
2841 */
2842 td->td_dupfd = dev2unit(dev);
2843 return (ENODEV);
2844}
2845
2846static struct cdevsw fildesc_cdevsw = {
2847 .d_version = D_VERSION,
2848 .d_flags = D_NEEDGIANT,
2849 .d_open = fdopen,
2850 .d_name = "FD",
2851};
2852
2853static void
2854fildesc_drvinit(void *unused)
2855{
2856 struct cdev *dev;
2857
2858 dev = make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "fd/0");
2859 make_dev_alias(dev, "stdin");
2860 dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1");
2861 make_dev_alias(dev, "stdout");
2862 dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2");
2863 make_dev_alias(dev, "stderr");
2864}
2865
2866SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL)
| 2651 default:
2652 return ("unkn");
2653 }
2654}
2655
2656/*
2657 * For the purposes of debugging, identify a process (if any, perhaps one of
2658 * many) that references the passed file in its file descriptor array. Return
2659 * NULL if none.
2660 */
2661static struct proc *
2662file_to_first_proc(struct file *fp)
2663{
2664 struct filedesc *fdp;
2665 struct proc *p;
2666 int n;
2667
2668 FOREACH_PROC_IN_SYSTEM(p) {
2669 if (p->p_state == PRS_NEW)
2670 continue;
2671 fdp = p->p_fd;
2672 if (fdp == NULL)
2673 continue;
2674 for (n = 0; n < fdp->fd_nfiles; n++) {
2675 if (fp == fdp->fd_ofiles[n])
2676 return (p);
2677 }
2678 }
2679 return (NULL);
2680}
2681
2682static void
2683db_print_file(struct file *fp, int header)
2684{
2685 struct proc *p;
2686
2687 if (header)
2688 db_printf("%8s %4s %8s %8s %4s %5s %6s %8s %5s %12s\n",
2689 "File", "Type", "Data", "Flag", "GCFl", "Count",
2690 "MCount", "Vnode", "FPID", "FCmd");
2691 p = file_to_first_proc(fp);
2692 db_printf("%8p %4s %8p %08x %04x %5d %6d %8p %5d %12s\n", fp,
2693 file_type_to_name(fp->f_type), fp->f_data, fp->f_flag,
2694 0, fp->f_count, 0, fp->f_vnode,
2695 p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-");
2696}
2697
2698DB_SHOW_COMMAND(file, db_show_file)
2699{
2700 struct file *fp;
2701
2702 if (!have_addr) {
2703 db_printf("usage: show file <addr>\n");
2704 return;
2705 }
2706 fp = (struct file *)addr;
2707 db_print_file(fp, 1);
2708}
2709
2710DB_SHOW_COMMAND(files, db_show_files)
2711{
2712 struct filedesc *fdp;
2713 struct file *fp;
2714 struct proc *p;
2715 int header;
2716 int n;
2717
2718 header = 1;
2719 FOREACH_PROC_IN_SYSTEM(p) {
2720 if (p->p_state == PRS_NEW)
2721 continue;
2722 if ((fdp = p->p_fd) == NULL)
2723 continue;
2724 for (n = 0; n < fdp->fd_nfiles; ++n) {
2725 if ((fp = fdp->fd_ofiles[n]) == NULL)
2726 continue;
2727 db_print_file(fp, header);
2728 header = 0;
2729 }
2730 }
2731}
2732#endif
2733
2734SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW,
2735 &maxfilesperproc, 0, "Maximum files allowed open per process");
2736
2737SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW,
2738 &maxfiles, 0, "Maximum number of files");
2739
2740SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD,
2741 __DEVOLATILE(int *, &openfiles), 0, "System-wide number of open files");
2742
2743/* ARGSUSED*/
2744static void
2745filelistinit(void *dummy)
2746{
2747
2748 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL,
2749 NULL, NULL, UMA_ALIGN_PTR, 0);
2750 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF);
2751 mtx_init(&fdesc_mtx, "fdesc", NULL, MTX_DEF);
2752}
2753SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL)
2754
2755/*-------------------------------------------------------------------*/
2756
2757static int
2758badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td)
2759{
2760
2761 return (EBADF);
2762}
2763
2764static int
2765badfo_truncate(struct file *fp, off_t length, struct ucred *active_cred, struct thread *td)
2766{
2767
2768 return (EINVAL);
2769}
2770
2771static int
2772badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, struct thread *td)
2773{
2774
2775 return (EBADF);
2776}
2777
2778static int
2779badfo_poll(struct file *fp, int events, struct ucred *active_cred, struct thread *td)
2780{
2781
2782 return (0);
2783}
2784
2785static int
2786badfo_kqfilter(struct file *fp, struct knote *kn)
2787{
2788
2789 return (EBADF);
2790}
2791
2792static int
2793badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, struct thread *td)
2794{
2795
2796 return (EBADF);
2797}
2798
2799static int
2800badfo_close(struct file *fp, struct thread *td)
2801{
2802
2803 return (EBADF);
2804}
2805
2806struct fileops badfileops = {
2807 .fo_read = badfo_readwrite,
2808 .fo_write = badfo_readwrite,
2809 .fo_truncate = badfo_truncate,
2810 .fo_ioctl = badfo_ioctl,
2811 .fo_poll = badfo_poll,
2812 .fo_kqfilter = badfo_kqfilter,
2813 .fo_stat = badfo_stat,
2814 .fo_close = badfo_close,
2815};
2816
2817
2818/*-------------------------------------------------------------------*/
2819
2820/*
2821 * File Descriptor pseudo-device driver (/dev/fd/).
2822 *
2823 * Opening minor device N dup()s the file (if any) connected to file
2824 * descriptor N belonging to the calling process. Note that this driver
2825 * consists of only the ``open()'' routine, because all subsequent
2826 * references to this file will be direct to the other driver.
2827 *
2828 * XXX: we could give this one a cloning event handler if necessary.
2829 */
2830
2831/* ARGSUSED */
2832static int
2833fdopen(struct cdev *dev, int mode, int type, struct thread *td)
2834{
2835
2836 /*
2837 * XXX Kludge: set curthread->td_dupfd to contain the value of the
2838 * the file descriptor being sought for duplication. The error
2839 * return ensures that the vnode for this device will be released
2840 * by vn_open. Open will detect this special error and take the
2841 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
2842 * will simply report the error.
2843 */
2844 td->td_dupfd = dev2unit(dev);
2845 return (ENODEV);
2846}
2847
2848static struct cdevsw fildesc_cdevsw = {
2849 .d_version = D_VERSION,
2850 .d_flags = D_NEEDGIANT,
2851 .d_open = fdopen,
2852 .d_name = "FD",
2853};
2854
2855static void
2856fildesc_drvinit(void *unused)
2857{
2858 struct cdev *dev;
2859
2860 dev = make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "fd/0");
2861 make_dev_alias(dev, "stdin");
2862 dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1");
2863 make_dev_alias(dev, "stdout");
2864 dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2");
2865 make_dev_alias(dev, "stderr");
2866}
2867
2868SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL)
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