kern_descrip.c revision 199617
1/*- 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94 35 */ 36 37#include <sys/cdefs.h> 38__FBSDID("$FreeBSD: head/sys/kern/kern_descrip.c 199617 2009-11-20 22:22:53Z kib $"); 39 40#include "opt_compat.h" 41#include "opt_ddb.h" 42#include "opt_ktrace.h" 43 44#include <sys/param.h> 45#include <sys/systm.h> 46 47#include <sys/conf.h> 48#include <sys/domain.h> 49#include <sys/fcntl.h> 50#include <sys/file.h> 51#include <sys/filedesc.h> 52#include <sys/filio.h> 53#include <sys/jail.h> 54#include <sys/kernel.h> 55#include <sys/limits.h> 56#include <sys/lock.h> 57#include <sys/malloc.h> 58#include <sys/mount.h> 59#include <sys/mqueue.h> 60#include <sys/mutex.h> 61#include <sys/namei.h> 62#include <sys/priv.h> 63#include <sys/proc.h> 64#include <sys/protosw.h> 65#include <sys/resourcevar.h> 66#include <sys/signalvar.h> 67#include <sys/socketvar.h> 68#include <sys/stat.h> 69#include <sys/sx.h> 70#include <sys/syscallsubr.h> 71#include <sys/sysctl.h> 72#include <sys/sysproto.h> 73#include <sys/tty.h> 74#include <sys/unistd.h> 75#include <sys/user.h> 76#include <sys/vnode.h> 77#ifdef KTRACE 78#include <sys/ktrace.h> 79#endif 80 81#include <security/audit/audit.h> 82 83#include <vm/uma.h> 84 85#include <ddb/ddb.h> 86 87static MALLOC_DEFINE(M_FILEDESC, "filedesc", "Open file descriptor table"); 88static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "filedesc_to_leader", 89 "file desc to leader structures"); 90static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 91 92static uma_zone_t file_zone; 93 94 95/* Flags for do_dup() */ 96#define DUP_FIXED 0x1 /* Force fixed allocation */ 97#define DUP_FCNTL 0x2 /* fcntl()-style errors */ 98 99static int do_dup(struct thread *td, int flags, int old, int new, 100 register_t *retval); 101static int fd_first_free(struct filedesc *, int, int); 102static int fd_last_used(struct filedesc *, int, int); 103static void fdgrowtable(struct filedesc *, int); 104static void fdunused(struct filedesc *fdp, int fd); 105static void fdused(struct filedesc *fdp, int fd); 106 107/* 108 * A process is initially started out with NDFILE descriptors stored within 109 * this structure, selected to be enough for typical applications based on 110 * the historical limit of 20 open files (and the usage of descriptors by 111 * shells). If these descriptors are exhausted, a larger descriptor table 112 * may be allocated, up to a process' resource limit; the internal arrays 113 * are then unused. 114 */ 115#define NDFILE 20 116#define NDSLOTSIZE sizeof(NDSLOTTYPE) 117#define NDENTRIES (NDSLOTSIZE * __CHAR_BIT) 118#define NDSLOT(x) ((x) / NDENTRIES) 119#define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES)) 120#define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES) 121 122/* 123 * Storage required per open file descriptor. 124 */ 125#define OFILESIZE (sizeof(struct file *) + sizeof(char)) 126 127/* 128 * Storage to hold unused ofiles that need to be reclaimed. 129 */ 130struct freetable { 131 struct file **ft_table; 132 SLIST_ENTRY(freetable) ft_next; 133}; 134 135/* 136 * Basic allocation of descriptors: 137 * one of the above, plus arrays for NDFILE descriptors. 138 */ 139struct filedesc0 { 140 struct filedesc fd_fd; 141 /* 142 * ofiles which need to be reclaimed on free. 143 */ 144 SLIST_HEAD(,freetable) fd_free; 145 /* 146 * These arrays are used when the number of open files is 147 * <= NDFILE, and are then pointed to by the pointers above. 148 */ 149 struct file *fd_dfiles[NDFILE]; 150 char fd_dfileflags[NDFILE]; 151 NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)]; 152}; 153 154/* 155 * Descriptor management. 156 */ 157volatile int openfiles; /* actual number of open files */ 158struct mtx sigio_lock; /* mtx to protect pointers to sigio */ 159void (*mq_fdclose)(struct thread *td, int fd, struct file *fp); 160 161/* A mutex to protect the association between a proc and filedesc. */ 162static struct mtx fdesc_mtx; 163 164/* 165 * Find the first zero bit in the given bitmap, starting at low and not 166 * exceeding size - 1. 167 */ 168static int 169fd_first_free(struct filedesc *fdp, int low, int size) 170{ 171 NDSLOTTYPE *map = fdp->fd_map; 172 NDSLOTTYPE mask; 173 int off, maxoff; 174 175 if (low >= size) 176 return (low); 177 178 off = NDSLOT(low); 179 if (low % NDENTRIES) { 180 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES))); 181 if ((mask &= ~map[off]) != 0UL) 182 return (off * NDENTRIES + ffsl(mask) - 1); 183 ++off; 184 } 185 for (maxoff = NDSLOTS(size); off < maxoff; ++off) 186 if (map[off] != ~0UL) 187 return (off * NDENTRIES + ffsl(~map[off]) - 1); 188 return (size); 189} 190 191/* 192 * Find the highest non-zero bit in the given bitmap, starting at low and 193 * not exceeding size - 1. 194 */ 195static int 196fd_last_used(struct filedesc *fdp, int low, int size) 197{ 198 NDSLOTTYPE *map = fdp->fd_map; 199 NDSLOTTYPE mask; 200 int off, minoff; 201 202 if (low >= size) 203 return (-1); 204 205 off = NDSLOT(size); 206 if (size % NDENTRIES) { 207 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES)); 208 if ((mask &= map[off]) != 0) 209 return (off * NDENTRIES + flsl(mask) - 1); 210 --off; 211 } 212 for (minoff = NDSLOT(low); off >= minoff; --off) 213 if (map[off] != 0) 214 return (off * NDENTRIES + flsl(map[off]) - 1); 215 return (low - 1); 216} 217 218static int 219fdisused(struct filedesc *fdp, int fd) 220{ 221 KASSERT(fd >= 0 && fd < fdp->fd_nfiles, 222 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles)); 223 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0); 224} 225 226/* 227 * Mark a file descriptor as used. 228 */ 229static void 230fdused(struct filedesc *fdp, int fd) 231{ 232 233 FILEDESC_XLOCK_ASSERT(fdp); 234 KASSERT(!fdisused(fdp, fd), 235 ("fd already used")); 236 237 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd); 238 if (fd > fdp->fd_lastfile) 239 fdp->fd_lastfile = fd; 240 if (fd == fdp->fd_freefile) 241 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 242} 243 244/* 245 * Mark a file descriptor as unused. 246 */ 247static void 248fdunused(struct filedesc *fdp, int fd) 249{ 250 251 FILEDESC_XLOCK_ASSERT(fdp); 252 KASSERT(fdisused(fdp, fd), 253 ("fd is already unused")); 254 KASSERT(fdp->fd_ofiles[fd] == NULL, 255 ("fd is still in use")); 256 257 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd); 258 if (fd < fdp->fd_freefile) 259 fdp->fd_freefile = fd; 260 if (fd == fdp->fd_lastfile) 261 fdp->fd_lastfile = fd_last_used(fdp, 0, fd); 262} 263 264/* 265 * System calls on descriptors. 266 */ 267#ifndef _SYS_SYSPROTO_H_ 268struct getdtablesize_args { 269 int dummy; 270}; 271#endif 272/* ARGSUSED */ 273int 274getdtablesize(struct thread *td, struct getdtablesize_args *uap) 275{ 276 struct proc *p = td->td_proc; 277 278 PROC_LOCK(p); 279 td->td_retval[0] = 280 min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 281 PROC_UNLOCK(p); 282 return (0); 283} 284 285/* 286 * Duplicate a file descriptor to a particular value. 287 * 288 * Note: keep in mind that a potential race condition exists when closing 289 * descriptors from a shared descriptor table (via rfork). 290 */ 291#ifndef _SYS_SYSPROTO_H_ 292struct dup2_args { 293 u_int from; 294 u_int to; 295}; 296#endif 297/* ARGSUSED */ 298int 299dup2(struct thread *td, struct dup2_args *uap) 300{ 301 302 return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to, 303 td->td_retval)); 304} 305 306/* 307 * Duplicate a file descriptor. 308 */ 309#ifndef _SYS_SYSPROTO_H_ 310struct dup_args { 311 u_int fd; 312}; 313#endif 314/* ARGSUSED */ 315int 316dup(struct thread *td, struct dup_args *uap) 317{ 318 319 return (do_dup(td, 0, (int)uap->fd, 0, td->td_retval)); 320} 321 322/* 323 * The file control system call. 324 */ 325#ifndef _SYS_SYSPROTO_H_ 326struct fcntl_args { 327 int fd; 328 int cmd; 329 long arg; 330}; 331#endif 332/* ARGSUSED */ 333int 334fcntl(struct thread *td, struct fcntl_args *uap) 335{ 336 struct flock fl; 337 struct oflock ofl; 338 intptr_t arg; 339 int error; 340 int cmd; 341 342 error = 0; 343 cmd = uap->cmd; 344 switch (uap->cmd) { 345 case F_OGETLK: 346 case F_OSETLK: 347 case F_OSETLKW: 348 /* 349 * Convert old flock structure to new. 350 */ 351 error = copyin((void *)(intptr_t)uap->arg, &ofl, sizeof(ofl)); 352 fl.l_start = ofl.l_start; 353 fl.l_len = ofl.l_len; 354 fl.l_pid = ofl.l_pid; 355 fl.l_type = ofl.l_type; 356 fl.l_whence = ofl.l_whence; 357 fl.l_sysid = 0; 358 359 switch (uap->cmd) { 360 case F_OGETLK: 361 cmd = F_GETLK; 362 break; 363 case F_OSETLK: 364 cmd = F_SETLK; 365 break; 366 case F_OSETLKW: 367 cmd = F_SETLKW; 368 break; 369 } 370 arg = (intptr_t)&fl; 371 break; 372 case F_GETLK: 373 case F_SETLK: 374 case F_SETLKW: 375 case F_SETLK_REMOTE: 376 error = copyin((void *)(intptr_t)uap->arg, &fl, sizeof(fl)); 377 arg = (intptr_t)&fl; 378 break; 379 default: 380 arg = uap->arg; 381 break; 382 } 383 if (error) 384 return (error); 385 error = kern_fcntl(td, uap->fd, cmd, arg); 386 if (error) 387 return (error); 388 if (uap->cmd == F_OGETLK) { 389 ofl.l_start = fl.l_start; 390 ofl.l_len = fl.l_len; 391 ofl.l_pid = fl.l_pid; 392 ofl.l_type = fl.l_type; 393 ofl.l_whence = fl.l_whence; 394 error = copyout(&ofl, (void *)(intptr_t)uap->arg, sizeof(ofl)); 395 } else if (uap->cmd == F_GETLK) { 396 error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl)); 397 } 398 return (error); 399} 400 401static inline struct file * 402fdtofp(int fd, struct filedesc *fdp) 403{ 404 struct file *fp; 405 406 FILEDESC_LOCK_ASSERT(fdp); 407 if ((unsigned)fd >= fdp->fd_nfiles || 408 (fp = fdp->fd_ofiles[fd]) == NULL) 409 return (NULL); 410 return (fp); 411} 412 413int 414kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) 415{ 416 struct filedesc *fdp; 417 struct flock *flp; 418 struct file *fp; 419 struct proc *p; 420 char *pop; 421 struct vnode *vp; 422 int error, flg, tmp; 423 int vfslocked; 424 u_int old, new; 425 uint64_t bsize; 426 427 vfslocked = 0; 428 error = 0; 429 flg = F_POSIX; 430 p = td->td_proc; 431 fdp = p->p_fd; 432 433 switch (cmd) { 434 case F_DUPFD: 435 tmp = arg; 436 error = do_dup(td, DUP_FCNTL, fd, tmp, td->td_retval); 437 break; 438 439 case F_DUP2FD: 440 tmp = arg; 441 error = do_dup(td, DUP_FIXED, fd, tmp, td->td_retval); 442 break; 443 444 case F_GETFD: 445 FILEDESC_SLOCK(fdp); 446 if ((fp = fdtofp(fd, fdp)) == NULL) { 447 FILEDESC_SUNLOCK(fdp); 448 error = EBADF; 449 break; 450 } 451 pop = &fdp->fd_ofileflags[fd]; 452 td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0; 453 FILEDESC_SUNLOCK(fdp); 454 break; 455 456 case F_SETFD: 457 FILEDESC_XLOCK(fdp); 458 if ((fp = fdtofp(fd, fdp)) == NULL) { 459 FILEDESC_XUNLOCK(fdp); 460 error = EBADF; 461 break; 462 } 463 pop = &fdp->fd_ofileflags[fd]; 464 *pop = (*pop &~ UF_EXCLOSE) | 465 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0); 466 FILEDESC_XUNLOCK(fdp); 467 break; 468 469 case F_GETFL: 470 FILEDESC_SLOCK(fdp); 471 if ((fp = fdtofp(fd, fdp)) == NULL) { 472 FILEDESC_SUNLOCK(fdp); 473 error = EBADF; 474 break; 475 } 476 td->td_retval[0] = OFLAGS(fp->f_flag); 477 FILEDESC_SUNLOCK(fdp); 478 break; 479 480 case F_SETFL: 481 FILEDESC_SLOCK(fdp); 482 if ((fp = fdtofp(fd, fdp)) == NULL) { 483 FILEDESC_SUNLOCK(fdp); 484 error = EBADF; 485 break; 486 } 487 fhold(fp); 488 FILEDESC_SUNLOCK(fdp); 489 do { 490 tmp = flg = fp->f_flag; 491 tmp &= ~FCNTLFLAGS; 492 tmp |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS; 493 } while(atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0); 494 tmp = fp->f_flag & FNONBLOCK; 495 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 496 if (error) { 497 fdrop(fp, td); 498 break; 499 } 500 tmp = fp->f_flag & FASYNC; 501 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); 502 if (error == 0) { 503 fdrop(fp, td); 504 break; 505 } 506 atomic_clear_int(&fp->f_flag, FNONBLOCK); 507 tmp = 0; 508 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 509 fdrop(fp, td); 510 break; 511 512 case F_GETOWN: 513 FILEDESC_SLOCK(fdp); 514 if ((fp = fdtofp(fd, fdp)) == NULL) { 515 FILEDESC_SUNLOCK(fdp); 516 error = EBADF; 517 break; 518 } 519 fhold(fp); 520 FILEDESC_SUNLOCK(fdp); 521 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td); 522 if (error == 0) 523 td->td_retval[0] = tmp; 524 fdrop(fp, td); 525 break; 526 527 case F_SETOWN: 528 FILEDESC_SLOCK(fdp); 529 if ((fp = fdtofp(fd, fdp)) == NULL) { 530 FILEDESC_SUNLOCK(fdp); 531 error = EBADF; 532 break; 533 } 534 fhold(fp); 535 FILEDESC_SUNLOCK(fdp); 536 tmp = arg; 537 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td); 538 fdrop(fp, td); 539 break; 540 541 case F_SETLK_REMOTE: 542 error = priv_check(td, PRIV_NFS_LOCKD); 543 if (error) 544 return (error); 545 flg = F_REMOTE; 546 goto do_setlk; 547 548 case F_SETLKW: 549 flg |= F_WAIT; 550 /* FALLTHROUGH F_SETLK */ 551 552 case F_SETLK: 553 do_setlk: 554 FILEDESC_SLOCK(fdp); 555 if ((fp = fdtofp(fd, fdp)) == NULL) { 556 FILEDESC_SUNLOCK(fdp); 557 error = EBADF; 558 break; 559 } 560 if (fp->f_type != DTYPE_VNODE) { 561 FILEDESC_SUNLOCK(fdp); 562 error = EBADF; 563 break; 564 } 565 flp = (struct flock *)arg; 566 if (flp->l_whence == SEEK_CUR) { 567 if (fp->f_offset < 0 || 568 (flp->l_start > 0 && 569 fp->f_offset > OFF_MAX - flp->l_start)) { 570 FILEDESC_SUNLOCK(fdp); 571 error = EOVERFLOW; 572 break; 573 } 574 flp->l_start += fp->f_offset; 575 } 576 577 /* 578 * VOP_ADVLOCK() may block. 579 */ 580 fhold(fp); 581 FILEDESC_SUNLOCK(fdp); 582 vp = fp->f_vnode; 583 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 584 switch (flp->l_type) { 585 case F_RDLCK: 586 if ((fp->f_flag & FREAD) == 0) { 587 error = EBADF; 588 break; 589 } 590 PROC_LOCK(p->p_leader); 591 p->p_leader->p_flag |= P_ADVLOCK; 592 PROC_UNLOCK(p->p_leader); 593 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 594 flp, flg); 595 break; 596 case F_WRLCK: 597 if ((fp->f_flag & FWRITE) == 0) { 598 error = EBADF; 599 break; 600 } 601 PROC_LOCK(p->p_leader); 602 p->p_leader->p_flag |= P_ADVLOCK; 603 PROC_UNLOCK(p->p_leader); 604 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 605 flp, flg); 606 break; 607 case F_UNLCK: 608 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 609 flp, flg); 610 break; 611 case F_UNLCKSYS: 612 /* 613 * Temporary api for testing remote lock 614 * infrastructure. 615 */ 616 if (flg != F_REMOTE) { 617 error = EINVAL; 618 break; 619 } 620 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 621 F_UNLCKSYS, flp, flg); 622 break; 623 default: 624 error = EINVAL; 625 break; 626 } 627 VFS_UNLOCK_GIANT(vfslocked); 628 vfslocked = 0; 629 /* Check for race with close */ 630 FILEDESC_SLOCK(fdp); 631 if ((unsigned) fd >= fdp->fd_nfiles || 632 fp != fdp->fd_ofiles[fd]) { 633 FILEDESC_SUNLOCK(fdp); 634 flp->l_whence = SEEK_SET; 635 flp->l_start = 0; 636 flp->l_len = 0; 637 flp->l_type = F_UNLCK; 638 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 639 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 640 F_UNLCK, flp, F_POSIX); 641 VFS_UNLOCK_GIANT(vfslocked); 642 vfslocked = 0; 643 } else 644 FILEDESC_SUNLOCK(fdp); 645 fdrop(fp, td); 646 break; 647 648 case F_GETLK: 649 FILEDESC_SLOCK(fdp); 650 if ((fp = fdtofp(fd, fdp)) == NULL) { 651 FILEDESC_SUNLOCK(fdp); 652 error = EBADF; 653 break; 654 } 655 if (fp->f_type != DTYPE_VNODE) { 656 FILEDESC_SUNLOCK(fdp); 657 error = EBADF; 658 break; 659 } 660 flp = (struct flock *)arg; 661 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK && 662 flp->l_type != F_UNLCK) { 663 FILEDESC_SUNLOCK(fdp); 664 error = EINVAL; 665 break; 666 } 667 if (flp->l_whence == SEEK_CUR) { 668 if ((flp->l_start > 0 && 669 fp->f_offset > OFF_MAX - flp->l_start) || 670 (flp->l_start < 0 && 671 fp->f_offset < OFF_MIN - flp->l_start)) { 672 FILEDESC_SUNLOCK(fdp); 673 error = EOVERFLOW; 674 break; 675 } 676 flp->l_start += fp->f_offset; 677 } 678 /* 679 * VOP_ADVLOCK() may block. 680 */ 681 fhold(fp); 682 FILEDESC_SUNLOCK(fdp); 683 vp = fp->f_vnode; 684 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 685 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp, 686 F_POSIX); 687 VFS_UNLOCK_GIANT(vfslocked); 688 vfslocked = 0; 689 fdrop(fp, td); 690 break; 691 692 case F_RDAHEAD: 693 arg = arg ? 128 * 1024: 0; 694 /* FALLTHROUGH */ 695 case F_READAHEAD: 696 FILEDESC_SLOCK(fdp); 697 if ((fp = fdtofp(fd, fdp)) == NULL) { 698 FILEDESC_SUNLOCK(fdp); 699 error = EBADF; 700 break; 701 } 702 if (fp->f_type != DTYPE_VNODE) { 703 FILEDESC_SUNLOCK(fdp); 704 error = EBADF; 705 break; 706 } 707 fhold(fp); 708 FILEDESC_SUNLOCK(fdp); 709 if (arg != 0) { 710 vp = fp->f_vnode; 711 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 712 error = vn_lock(vp, LK_SHARED); 713 if (error != 0) 714 goto readahead_vnlock_fail; 715 bsize = fp->f_vnode->v_mount->mnt_stat.f_iosize; 716 VOP_UNLOCK(vp, 0); 717 fp->f_seqcount = (arg + bsize - 1) / bsize; 718 do { 719 new = old = fp->f_flag; 720 new |= FRDAHEAD; 721 } while (!atomic_cmpset_rel_int(&fp->f_flag, old, new)); 722readahead_vnlock_fail: 723 VFS_UNLOCK_GIANT(vfslocked); 724 vfslocked = 0; 725 } else { 726 do { 727 new = old = fp->f_flag; 728 new &= ~FRDAHEAD; 729 } while (!atomic_cmpset_rel_int(&fp->f_flag, old, new)); 730 } 731 fdrop(fp, td); 732 break; 733 734 default: 735 error = EINVAL; 736 break; 737 } 738 VFS_UNLOCK_GIANT(vfslocked); 739 return (error); 740} 741 742/* 743 * Common code for dup, dup2, fcntl(F_DUPFD) and fcntl(F_DUP2FD). 744 */ 745static int 746do_dup(struct thread *td, int flags, int old, int new, 747 register_t *retval) 748{ 749 struct filedesc *fdp; 750 struct proc *p; 751 struct file *fp; 752 struct file *delfp; 753 int error, holdleaders, maxfd; 754 755 p = td->td_proc; 756 fdp = p->p_fd; 757 758 /* 759 * Verify we have a valid descriptor to dup from and possibly to 760 * dup to. Unlike dup() and dup2(), fcntl()'s F_DUPFD should 761 * return EINVAL when the new descriptor is out of bounds. 762 */ 763 if (old < 0) 764 return (EBADF); 765 if (new < 0) 766 return (flags & DUP_FCNTL ? EINVAL : EBADF); 767 PROC_LOCK(p); 768 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 769 PROC_UNLOCK(p); 770 if (new >= maxfd) 771 return (flags & DUP_FCNTL ? EINVAL : EMFILE); 772 773 FILEDESC_XLOCK(fdp); 774 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) { 775 FILEDESC_XUNLOCK(fdp); 776 return (EBADF); 777 } 778 if (flags & DUP_FIXED && old == new) { 779 *retval = new; 780 FILEDESC_XUNLOCK(fdp); 781 return (0); 782 } 783 fp = fdp->fd_ofiles[old]; 784 fhold(fp); 785 786 /* 787 * If the caller specified a file descriptor, make sure the file 788 * table is large enough to hold it, and grab it. Otherwise, just 789 * allocate a new descriptor the usual way. Since the filedesc 790 * lock may be temporarily dropped in the process, we have to look 791 * out for a race. 792 */ 793 if (flags & DUP_FIXED) { 794 if (new >= fdp->fd_nfiles) 795 fdgrowtable(fdp, new + 1); 796 if (fdp->fd_ofiles[new] == NULL) 797 fdused(fdp, new); 798 } else { 799 if ((error = fdalloc(td, new, &new)) != 0) { 800 FILEDESC_XUNLOCK(fdp); 801 fdrop(fp, td); 802 return (error); 803 } 804 } 805 806 /* 807 * If the old file changed out from under us then treat it as a 808 * bad file descriptor. Userland should do its own locking to 809 * avoid this case. 810 */ 811 if (fdp->fd_ofiles[old] != fp) { 812 /* we've allocated a descriptor which we won't use */ 813 if (fdp->fd_ofiles[new] == NULL) 814 fdunused(fdp, new); 815 FILEDESC_XUNLOCK(fdp); 816 fdrop(fp, td); 817 return (EBADF); 818 } 819 KASSERT(old != new, 820 ("new fd is same as old")); 821 822 /* 823 * Save info on the descriptor being overwritten. We cannot close 824 * it without introducing an ownership race for the slot, since we 825 * need to drop the filedesc lock to call closef(). 826 * 827 * XXX this duplicates parts of close(). 828 */ 829 delfp = fdp->fd_ofiles[new]; 830 holdleaders = 0; 831 if (delfp != NULL) { 832 if (td->td_proc->p_fdtol != NULL) { 833 /* 834 * Ask fdfree() to sleep to ensure that all relevant 835 * process leaders can be traversed in closef(). 836 */ 837 fdp->fd_holdleaderscount++; 838 holdleaders = 1; 839 } 840 } 841 842 /* 843 * Duplicate the source descriptor 844 */ 845 fdp->fd_ofiles[new] = fp; 846 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE; 847 if (new > fdp->fd_lastfile) 848 fdp->fd_lastfile = new; 849 *retval = new; 850 851 /* 852 * If we dup'd over a valid file, we now own the reference to it 853 * and must dispose of it using closef() semantics (as if a 854 * close() were performed on it). 855 * 856 * XXX this duplicates parts of close(). 857 */ 858 if (delfp != NULL) { 859 knote_fdclose(td, new); 860 if (delfp->f_type == DTYPE_MQUEUE) 861 mq_fdclose(td, new, delfp); 862 FILEDESC_XUNLOCK(fdp); 863 (void) closef(delfp, td); 864 if (holdleaders) { 865 FILEDESC_XLOCK(fdp); 866 fdp->fd_holdleaderscount--; 867 if (fdp->fd_holdleaderscount == 0 && 868 fdp->fd_holdleaderswakeup != 0) { 869 fdp->fd_holdleaderswakeup = 0; 870 wakeup(&fdp->fd_holdleaderscount); 871 } 872 FILEDESC_XUNLOCK(fdp); 873 } 874 } else { 875 FILEDESC_XUNLOCK(fdp); 876 } 877 return (0); 878} 879 880/* 881 * If sigio is on the list associated with a process or process group, 882 * disable signalling from the device, remove sigio from the list and 883 * free sigio. 884 */ 885void 886funsetown(struct sigio **sigiop) 887{ 888 struct sigio *sigio; 889 890 SIGIO_LOCK(); 891 sigio = *sigiop; 892 if (sigio == NULL) { 893 SIGIO_UNLOCK(); 894 return; 895 } 896 *(sigio->sio_myref) = NULL; 897 if ((sigio)->sio_pgid < 0) { 898 struct pgrp *pg = (sigio)->sio_pgrp; 899 PGRP_LOCK(pg); 900 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 901 sigio, sio_pgsigio); 902 PGRP_UNLOCK(pg); 903 } else { 904 struct proc *p = (sigio)->sio_proc; 905 PROC_LOCK(p); 906 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 907 sigio, sio_pgsigio); 908 PROC_UNLOCK(p); 909 } 910 SIGIO_UNLOCK(); 911 crfree(sigio->sio_ucred); 912 free(sigio, M_SIGIO); 913} 914 915/* 916 * Free a list of sigio structures. 917 * We only need to lock the SIGIO_LOCK because we have made ourselves 918 * inaccessible to callers of fsetown and therefore do not need to lock 919 * the proc or pgrp struct for the list manipulation. 920 */ 921void 922funsetownlst(struct sigiolst *sigiolst) 923{ 924 struct proc *p; 925 struct pgrp *pg; 926 struct sigio *sigio; 927 928 sigio = SLIST_FIRST(sigiolst); 929 if (sigio == NULL) 930 return; 931 p = NULL; 932 pg = NULL; 933 934 /* 935 * Every entry of the list should belong 936 * to a single proc or pgrp. 937 */ 938 if (sigio->sio_pgid < 0) { 939 pg = sigio->sio_pgrp; 940 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED); 941 } else /* if (sigio->sio_pgid > 0) */ { 942 p = sigio->sio_proc; 943 PROC_LOCK_ASSERT(p, MA_NOTOWNED); 944 } 945 946 SIGIO_LOCK(); 947 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) { 948 *(sigio->sio_myref) = NULL; 949 if (pg != NULL) { 950 KASSERT(sigio->sio_pgid < 0, 951 ("Proc sigio in pgrp sigio list")); 952 KASSERT(sigio->sio_pgrp == pg, 953 ("Bogus pgrp in sigio list")); 954 PGRP_LOCK(pg); 955 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio, 956 sio_pgsigio); 957 PGRP_UNLOCK(pg); 958 } else /* if (p != NULL) */ { 959 KASSERT(sigio->sio_pgid > 0, 960 ("Pgrp sigio in proc sigio list")); 961 KASSERT(sigio->sio_proc == p, 962 ("Bogus proc in sigio list")); 963 PROC_LOCK(p); 964 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, 965 sio_pgsigio); 966 PROC_UNLOCK(p); 967 } 968 SIGIO_UNLOCK(); 969 crfree(sigio->sio_ucred); 970 free(sigio, M_SIGIO); 971 SIGIO_LOCK(); 972 } 973 SIGIO_UNLOCK(); 974} 975 976/* 977 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 978 * 979 * After permission checking, add a sigio structure to the sigio list for 980 * the process or process group. 981 */ 982int 983fsetown(pid_t pgid, struct sigio **sigiop) 984{ 985 struct proc *proc; 986 struct pgrp *pgrp; 987 struct sigio *sigio; 988 int ret; 989 990 if (pgid == 0) { 991 funsetown(sigiop); 992 return (0); 993 } 994 995 ret = 0; 996 997 /* Allocate and fill in the new sigio out of locks. */ 998 sigio = malloc(sizeof(struct sigio), M_SIGIO, M_WAITOK); 999 sigio->sio_pgid = pgid; 1000 sigio->sio_ucred = crhold(curthread->td_ucred); 1001 sigio->sio_myref = sigiop; 1002 1003 sx_slock(&proctree_lock); 1004 if (pgid > 0) { 1005 proc = pfind(pgid); 1006 if (proc == NULL) { 1007 ret = ESRCH; 1008 goto fail; 1009 } 1010 1011 /* 1012 * Policy - Don't allow a process to FSETOWN a process 1013 * in another session. 1014 * 1015 * Remove this test to allow maximum flexibility or 1016 * restrict FSETOWN to the current process or process 1017 * group for maximum safety. 1018 */ 1019 PROC_UNLOCK(proc); 1020 if (proc->p_session != curthread->td_proc->p_session) { 1021 ret = EPERM; 1022 goto fail; 1023 } 1024 1025 pgrp = NULL; 1026 } else /* if (pgid < 0) */ { 1027 pgrp = pgfind(-pgid); 1028 if (pgrp == NULL) { 1029 ret = ESRCH; 1030 goto fail; 1031 } 1032 PGRP_UNLOCK(pgrp); 1033 1034 /* 1035 * Policy - Don't allow a process to FSETOWN a process 1036 * in another session. 1037 * 1038 * Remove this test to allow maximum flexibility or 1039 * restrict FSETOWN to the current process or process 1040 * group for maximum safety. 1041 */ 1042 if (pgrp->pg_session != curthread->td_proc->p_session) { 1043 ret = EPERM; 1044 goto fail; 1045 } 1046 1047 proc = NULL; 1048 } 1049 funsetown(sigiop); 1050 if (pgid > 0) { 1051 PROC_LOCK(proc); 1052 /* 1053 * Since funsetownlst() is called without the proctree 1054 * locked, we need to check for P_WEXIT. 1055 * XXX: is ESRCH correct? 1056 */ 1057 if ((proc->p_flag & P_WEXIT) != 0) { 1058 PROC_UNLOCK(proc); 1059 ret = ESRCH; 1060 goto fail; 1061 } 1062 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 1063 sigio->sio_proc = proc; 1064 PROC_UNLOCK(proc); 1065 } else { 1066 PGRP_LOCK(pgrp); 1067 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 1068 sigio->sio_pgrp = pgrp; 1069 PGRP_UNLOCK(pgrp); 1070 } 1071 sx_sunlock(&proctree_lock); 1072 SIGIO_LOCK(); 1073 *sigiop = sigio; 1074 SIGIO_UNLOCK(); 1075 return (0); 1076 1077fail: 1078 sx_sunlock(&proctree_lock); 1079 crfree(sigio->sio_ucred); 1080 free(sigio, M_SIGIO); 1081 return (ret); 1082} 1083 1084/* 1085 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 1086 */ 1087pid_t 1088fgetown(sigiop) 1089 struct sigio **sigiop; 1090{ 1091 pid_t pgid; 1092 1093 SIGIO_LOCK(); 1094 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0; 1095 SIGIO_UNLOCK(); 1096 return (pgid); 1097} 1098 1099/* 1100 * Close a file descriptor. 1101 */ 1102#ifndef _SYS_SYSPROTO_H_ 1103struct close_args { 1104 int fd; 1105}; 1106#endif 1107/* ARGSUSED */ 1108int 1109close(td, uap) 1110 struct thread *td; 1111 struct close_args *uap; 1112{ 1113 1114 return (kern_close(td, uap->fd)); 1115} 1116 1117int 1118kern_close(td, fd) 1119 struct thread *td; 1120 int fd; 1121{ 1122 struct filedesc *fdp; 1123 struct file *fp; 1124 int error; 1125 int holdleaders; 1126 1127 error = 0; 1128 holdleaders = 0; 1129 fdp = td->td_proc->p_fd; 1130 1131 AUDIT_SYSCLOSE(td, fd); 1132 1133 FILEDESC_XLOCK(fdp); 1134 if ((unsigned)fd >= fdp->fd_nfiles || 1135 (fp = fdp->fd_ofiles[fd]) == NULL) { 1136 FILEDESC_XUNLOCK(fdp); 1137 return (EBADF); 1138 } 1139 fdp->fd_ofiles[fd] = NULL; 1140 fdp->fd_ofileflags[fd] = 0; 1141 fdunused(fdp, fd); 1142 if (td->td_proc->p_fdtol != NULL) { 1143 /* 1144 * Ask fdfree() to sleep to ensure that all relevant 1145 * process leaders can be traversed in closef(). 1146 */ 1147 fdp->fd_holdleaderscount++; 1148 holdleaders = 1; 1149 } 1150 1151 /* 1152 * We now hold the fp reference that used to be owned by the 1153 * descriptor array. We have to unlock the FILEDESC *AFTER* 1154 * knote_fdclose to prevent a race of the fd getting opened, a knote 1155 * added, and deleteing a knote for the new fd. 1156 */ 1157 knote_fdclose(td, fd); 1158 if (fp->f_type == DTYPE_MQUEUE) 1159 mq_fdclose(td, fd, fp); 1160 FILEDESC_XUNLOCK(fdp); 1161 1162 error = closef(fp, td); 1163 if (holdleaders) { 1164 FILEDESC_XLOCK(fdp); 1165 fdp->fd_holdleaderscount--; 1166 if (fdp->fd_holdleaderscount == 0 && 1167 fdp->fd_holdleaderswakeup != 0) { 1168 fdp->fd_holdleaderswakeup = 0; 1169 wakeup(&fdp->fd_holdleaderscount); 1170 } 1171 FILEDESC_XUNLOCK(fdp); 1172 } 1173 return (error); 1174} 1175 1176/* 1177 * Close open file descriptors. 1178 */ 1179#ifndef _SYS_SYSPROTO_H_ 1180struct closefrom_args { 1181 int lowfd; 1182}; 1183#endif 1184/* ARGSUSED */ 1185int 1186closefrom(struct thread *td, struct closefrom_args *uap) 1187{ 1188 struct filedesc *fdp; 1189 int fd; 1190 1191 fdp = td->td_proc->p_fd; 1192 AUDIT_ARG_FD(uap->lowfd); 1193 1194 /* 1195 * Treat negative starting file descriptor values identical to 1196 * closefrom(0) which closes all files. 1197 */ 1198 if (uap->lowfd < 0) 1199 uap->lowfd = 0; 1200 FILEDESC_SLOCK(fdp); 1201 for (fd = uap->lowfd; fd < fdp->fd_nfiles; fd++) { 1202 if (fdp->fd_ofiles[fd] != NULL) { 1203 FILEDESC_SUNLOCK(fdp); 1204 (void)kern_close(td, fd); 1205 FILEDESC_SLOCK(fdp); 1206 } 1207 } 1208 FILEDESC_SUNLOCK(fdp); 1209 return (0); 1210} 1211 1212#if defined(COMPAT_43) 1213/* 1214 * Return status information about a file descriptor. 1215 */ 1216#ifndef _SYS_SYSPROTO_H_ 1217struct ofstat_args { 1218 int fd; 1219 struct ostat *sb; 1220}; 1221#endif 1222/* ARGSUSED */ 1223int 1224ofstat(struct thread *td, struct ofstat_args *uap) 1225{ 1226 struct ostat oub; 1227 struct stat ub; 1228 int error; 1229 1230 error = kern_fstat(td, uap->fd, &ub); 1231 if (error == 0) { 1232 cvtstat(&ub, &oub); 1233 error = copyout(&oub, uap->sb, sizeof(oub)); 1234 } 1235 return (error); 1236} 1237#endif /* COMPAT_43 */ 1238 1239/* 1240 * Return status information about a file descriptor. 1241 */ 1242#ifndef _SYS_SYSPROTO_H_ 1243struct fstat_args { 1244 int fd; 1245 struct stat *sb; 1246}; 1247#endif 1248/* ARGSUSED */ 1249int 1250fstat(struct thread *td, struct fstat_args *uap) 1251{ 1252 struct stat ub; 1253 int error; 1254 1255 error = kern_fstat(td, uap->fd, &ub); 1256 if (error == 0) 1257 error = copyout(&ub, uap->sb, sizeof(ub)); 1258 return (error); 1259} 1260 1261int 1262kern_fstat(struct thread *td, int fd, struct stat *sbp) 1263{ 1264 struct file *fp; 1265 int error; 1266 1267 AUDIT_ARG_FD(fd); 1268 1269 if ((error = fget(td, fd, &fp)) != 0) 1270 return (error); 1271 1272 AUDIT_ARG_FILE(td->td_proc, fp); 1273 1274 error = fo_stat(fp, sbp, td->td_ucred, td); 1275 fdrop(fp, td); 1276#ifdef KTRACE 1277 if (error == 0 && KTRPOINT(td, KTR_STRUCT)) 1278 ktrstat(sbp); 1279#endif 1280 return (error); 1281} 1282 1283/* 1284 * Return status information about a file descriptor. 1285 */ 1286#ifndef _SYS_SYSPROTO_H_ 1287struct nfstat_args { 1288 int fd; 1289 struct nstat *sb; 1290}; 1291#endif 1292/* ARGSUSED */ 1293int 1294nfstat(struct thread *td, struct nfstat_args *uap) 1295{ 1296 struct nstat nub; 1297 struct stat ub; 1298 int error; 1299 1300 error = kern_fstat(td, uap->fd, &ub); 1301 if (error == 0) { 1302 cvtnstat(&ub, &nub); 1303 error = copyout(&nub, uap->sb, sizeof(nub)); 1304 } 1305 return (error); 1306} 1307 1308/* 1309 * Return pathconf information about a file descriptor. 1310 */ 1311#ifndef _SYS_SYSPROTO_H_ 1312struct fpathconf_args { 1313 int fd; 1314 int name; 1315}; 1316#endif 1317/* ARGSUSED */ 1318int 1319fpathconf(struct thread *td, struct fpathconf_args *uap) 1320{ 1321 struct file *fp; 1322 struct vnode *vp; 1323 int error; 1324 1325 if ((error = fget(td, uap->fd, &fp)) != 0) 1326 return (error); 1327 1328 /* If asynchronous I/O is available, it works for all descriptors. */ 1329 if (uap->name == _PC_ASYNC_IO) { 1330 td->td_retval[0] = async_io_version; 1331 goto out; 1332 } 1333 vp = fp->f_vnode; 1334 if (vp != NULL) { 1335 int vfslocked; 1336 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 1337 vn_lock(vp, LK_SHARED | LK_RETRY); 1338 error = VOP_PATHCONF(vp, uap->name, td->td_retval); 1339 VOP_UNLOCK(vp, 0); 1340 VFS_UNLOCK_GIANT(vfslocked); 1341 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) { 1342 if (uap->name != _PC_PIPE_BUF) { 1343 error = EINVAL; 1344 } else { 1345 td->td_retval[0] = PIPE_BUF; 1346 error = 0; 1347 } 1348 } else { 1349 error = EOPNOTSUPP; 1350 } 1351out: 1352 fdrop(fp, td); 1353 return (error); 1354} 1355 1356/* 1357 * Grow the file table to accomodate (at least) nfd descriptors. This may 1358 * block and drop the filedesc lock, but it will reacquire it before 1359 * returning. 1360 */ 1361static void 1362fdgrowtable(struct filedesc *fdp, int nfd) 1363{ 1364 struct filedesc0 *fdp0; 1365 struct freetable *fo; 1366 struct file **ntable; 1367 struct file **otable; 1368 char *nfileflags; 1369 int nnfiles, onfiles; 1370 NDSLOTTYPE *nmap; 1371 1372 FILEDESC_XLOCK_ASSERT(fdp); 1373 1374 KASSERT(fdp->fd_nfiles > 0, 1375 ("zero-length file table")); 1376 1377 /* compute the size of the new table */ 1378 onfiles = fdp->fd_nfiles; 1379 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */ 1380 if (nnfiles <= onfiles) 1381 /* the table is already large enough */ 1382 return; 1383 1384 /* allocate a new table and (if required) new bitmaps */ 1385 FILEDESC_XUNLOCK(fdp); 1386 ntable = malloc((nnfiles * OFILESIZE) + sizeof(struct freetable), 1387 M_FILEDESC, M_ZERO | M_WAITOK); 1388 nfileflags = (char *)&ntable[nnfiles]; 1389 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) 1390 nmap = malloc(NDSLOTS(nnfiles) * NDSLOTSIZE, 1391 M_FILEDESC, M_ZERO | M_WAITOK); 1392 else 1393 nmap = NULL; 1394 FILEDESC_XLOCK(fdp); 1395 1396 /* 1397 * We now have new tables ready to go. Since we dropped the 1398 * filedesc lock to call malloc(), watch out for a race. 1399 */ 1400 onfiles = fdp->fd_nfiles; 1401 if (onfiles >= nnfiles) { 1402 /* we lost the race, but that's OK */ 1403 free(ntable, M_FILEDESC); 1404 if (nmap != NULL) 1405 free(nmap, M_FILEDESC); 1406 return; 1407 } 1408 bcopy(fdp->fd_ofiles, ntable, onfiles * sizeof(*ntable)); 1409 bcopy(fdp->fd_ofileflags, nfileflags, onfiles); 1410 otable = fdp->fd_ofiles; 1411 fdp->fd_ofileflags = nfileflags; 1412 fdp->fd_ofiles = ntable; 1413 /* 1414 * We must preserve ofiles until the process exits because we can't 1415 * be certain that no threads have references to the old table via 1416 * _fget(). 1417 */ 1418 if (onfiles > NDFILE) { 1419 fo = (struct freetable *)&otable[onfiles]; 1420 fdp0 = (struct filedesc0 *)fdp; 1421 fo->ft_table = otable; 1422 SLIST_INSERT_HEAD(&fdp0->fd_free, fo, ft_next); 1423 } 1424 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) { 1425 bcopy(fdp->fd_map, nmap, NDSLOTS(onfiles) * sizeof(*nmap)); 1426 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE)) 1427 free(fdp->fd_map, M_FILEDESC); 1428 fdp->fd_map = nmap; 1429 } 1430 fdp->fd_nfiles = nnfiles; 1431} 1432 1433/* 1434 * Allocate a file descriptor for the process. 1435 */ 1436int 1437fdalloc(struct thread *td, int minfd, int *result) 1438{ 1439 struct proc *p = td->td_proc; 1440 struct filedesc *fdp = p->p_fd; 1441 int fd = -1, maxfd; 1442 1443 FILEDESC_XLOCK_ASSERT(fdp); 1444 1445 if (fdp->fd_freefile > minfd) 1446 minfd = fdp->fd_freefile; 1447 1448 PROC_LOCK(p); 1449 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1450 PROC_UNLOCK(p); 1451 1452 /* 1453 * Search the bitmap for a free descriptor. If none is found, try 1454 * to grow the file table. Keep at it until we either get a file 1455 * descriptor or run into process or system limits; fdgrowtable() 1456 * may drop the filedesc lock, so we're in a race. 1457 */ 1458 for (;;) { 1459 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); 1460 if (fd >= maxfd) 1461 return (EMFILE); 1462 if (fd < fdp->fd_nfiles) 1463 break; 1464 fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd)); 1465 } 1466 1467 /* 1468 * Perform some sanity checks, then mark the file descriptor as 1469 * used and return it to the caller. 1470 */ 1471 KASSERT(!fdisused(fdp, fd), 1472 ("fd_first_free() returned non-free descriptor")); 1473 KASSERT(fdp->fd_ofiles[fd] == NULL, 1474 ("free descriptor isn't")); 1475 fdp->fd_ofileflags[fd] = 0; /* XXX needed? */ 1476 fdused(fdp, fd); 1477 *result = fd; 1478 return (0); 1479} 1480 1481/* 1482 * Check to see whether n user file descriptors are available to the process 1483 * p. 1484 */ 1485int 1486fdavail(struct thread *td, int n) 1487{ 1488 struct proc *p = td->td_proc; 1489 struct filedesc *fdp = td->td_proc->p_fd; 1490 struct file **fpp; 1491 int i, lim, last; 1492 1493 FILEDESC_LOCK_ASSERT(fdp); 1494 1495 PROC_LOCK(p); 1496 lim = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1497 PROC_UNLOCK(p); 1498 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) 1499 return (1); 1500 last = min(fdp->fd_nfiles, lim); 1501 fpp = &fdp->fd_ofiles[fdp->fd_freefile]; 1502 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) { 1503 if (*fpp == NULL && --n <= 0) 1504 return (1); 1505 } 1506 return (0); 1507} 1508 1509/* 1510 * Create a new open file structure and allocate a file decriptor for the 1511 * process that refers to it. We add one reference to the file for the 1512 * descriptor table and one reference for resultfp. This is to prevent us 1513 * being preempted and the entry in the descriptor table closed after we 1514 * release the FILEDESC lock. 1515 */ 1516int 1517falloc(struct thread *td, struct file **resultfp, int *resultfd) 1518{ 1519 struct proc *p = td->td_proc; 1520 struct file *fp; 1521 int error, i; 1522 int maxuserfiles = maxfiles - (maxfiles / 20); 1523 static struct timeval lastfail; 1524 static int curfail; 1525 1526 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO); 1527 if ((openfiles >= maxuserfiles && 1528 priv_check(td, PRIV_MAXFILES) != 0) || 1529 openfiles >= maxfiles) { 1530 if (ppsratecheck(&lastfail, &curfail, 1)) { 1531 printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n", 1532 td->td_ucred->cr_ruid); 1533 } 1534 uma_zfree(file_zone, fp); 1535 return (ENFILE); 1536 } 1537 atomic_add_int(&openfiles, 1); 1538 1539 /* 1540 * If the process has file descriptor zero open, add the new file 1541 * descriptor to the list of open files at that point, otherwise 1542 * put it at the front of the list of open files. 1543 */ 1544 refcount_init(&fp->f_count, 1); 1545 if (resultfp) 1546 fhold(fp); 1547 fp->f_cred = crhold(td->td_ucred); 1548 fp->f_ops = &badfileops; 1549 fp->f_data = NULL; 1550 fp->f_vnode = NULL; 1551 FILEDESC_XLOCK(p->p_fd); 1552 if ((error = fdalloc(td, 0, &i))) { 1553 FILEDESC_XUNLOCK(p->p_fd); 1554 fdrop(fp, td); 1555 if (resultfp) 1556 fdrop(fp, td); 1557 return (error); 1558 } 1559 p->p_fd->fd_ofiles[i] = fp; 1560 FILEDESC_XUNLOCK(p->p_fd); 1561 if (resultfp) 1562 *resultfp = fp; 1563 if (resultfd) 1564 *resultfd = i; 1565 return (0); 1566} 1567 1568/* 1569 * Build a new filedesc structure from another. 1570 * Copy the current, root, and jail root vnode references. 1571 */ 1572struct filedesc * 1573fdinit(struct filedesc *fdp) 1574{ 1575 struct filedesc0 *newfdp; 1576 1577 newfdp = malloc(sizeof *newfdp, M_FILEDESC, M_WAITOK | M_ZERO); 1578 FILEDESC_LOCK_INIT(&newfdp->fd_fd); 1579 if (fdp != NULL) { 1580 FILEDESC_XLOCK(fdp); 1581 newfdp->fd_fd.fd_cdir = fdp->fd_cdir; 1582 if (newfdp->fd_fd.fd_cdir) 1583 VREF(newfdp->fd_fd.fd_cdir); 1584 newfdp->fd_fd.fd_rdir = fdp->fd_rdir; 1585 if (newfdp->fd_fd.fd_rdir) 1586 VREF(newfdp->fd_fd.fd_rdir); 1587 newfdp->fd_fd.fd_jdir = fdp->fd_jdir; 1588 if (newfdp->fd_fd.fd_jdir) 1589 VREF(newfdp->fd_fd.fd_jdir); 1590 FILEDESC_XUNLOCK(fdp); 1591 } 1592 1593 /* Create the file descriptor table. */ 1594 newfdp->fd_fd.fd_refcnt = 1; 1595 newfdp->fd_fd.fd_holdcnt = 1; 1596 newfdp->fd_fd.fd_cmask = CMASK; 1597 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; 1598 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; 1599 newfdp->fd_fd.fd_nfiles = NDFILE; 1600 newfdp->fd_fd.fd_map = newfdp->fd_dmap; 1601 newfdp->fd_fd.fd_lastfile = -1; 1602 return (&newfdp->fd_fd); 1603} 1604 1605static struct filedesc * 1606fdhold(struct proc *p) 1607{ 1608 struct filedesc *fdp; 1609 1610 mtx_lock(&fdesc_mtx); 1611 fdp = p->p_fd; 1612 if (fdp != NULL) 1613 fdp->fd_holdcnt++; 1614 mtx_unlock(&fdesc_mtx); 1615 return (fdp); 1616} 1617 1618static void 1619fddrop(struct filedesc *fdp) 1620{ 1621 struct filedesc0 *fdp0; 1622 struct freetable *ft; 1623 int i; 1624 1625 mtx_lock(&fdesc_mtx); 1626 i = --fdp->fd_holdcnt; 1627 mtx_unlock(&fdesc_mtx); 1628 if (i > 0) 1629 return; 1630 1631 FILEDESC_LOCK_DESTROY(fdp); 1632 fdp0 = (struct filedesc0 *)fdp; 1633 while ((ft = SLIST_FIRST(&fdp0->fd_free)) != NULL) { 1634 SLIST_REMOVE_HEAD(&fdp0->fd_free, ft_next); 1635 free(ft->ft_table, M_FILEDESC); 1636 } 1637 free(fdp, M_FILEDESC); 1638} 1639 1640/* 1641 * Share a filedesc structure. 1642 */ 1643struct filedesc * 1644fdshare(struct filedesc *fdp) 1645{ 1646 1647 FILEDESC_XLOCK(fdp); 1648 fdp->fd_refcnt++; 1649 FILEDESC_XUNLOCK(fdp); 1650 return (fdp); 1651} 1652 1653/* 1654 * Unshare a filedesc structure, if necessary by making a copy 1655 */ 1656void 1657fdunshare(struct proc *p, struct thread *td) 1658{ 1659 1660 FILEDESC_XLOCK(p->p_fd); 1661 if (p->p_fd->fd_refcnt > 1) { 1662 struct filedesc *tmp; 1663 1664 FILEDESC_XUNLOCK(p->p_fd); 1665 tmp = fdcopy(p->p_fd); 1666 fdfree(td); 1667 p->p_fd = tmp; 1668 } else 1669 FILEDESC_XUNLOCK(p->p_fd); 1670} 1671 1672/* 1673 * Copy a filedesc structure. A NULL pointer in returns a NULL reference, 1674 * this is to ease callers, not catch errors. 1675 */ 1676struct filedesc * 1677fdcopy(struct filedesc *fdp) 1678{ 1679 struct filedesc *newfdp; 1680 int i; 1681 1682 /* Certain daemons might not have file descriptors. */ 1683 if (fdp == NULL) 1684 return (NULL); 1685 1686 newfdp = fdinit(fdp); 1687 FILEDESC_SLOCK(fdp); 1688 while (fdp->fd_lastfile >= newfdp->fd_nfiles) { 1689 FILEDESC_SUNLOCK(fdp); 1690 FILEDESC_XLOCK(newfdp); 1691 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1692 FILEDESC_XUNLOCK(newfdp); 1693 FILEDESC_SLOCK(fdp); 1694 } 1695 /* copy everything except kqueue descriptors */ 1696 newfdp->fd_freefile = -1; 1697 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1698 if (fdisused(fdp, i) && 1699 fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE && 1700 fdp->fd_ofiles[i]->f_ops != &badfileops) { 1701 newfdp->fd_ofiles[i] = fdp->fd_ofiles[i]; 1702 newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i]; 1703 fhold(newfdp->fd_ofiles[i]); 1704 newfdp->fd_lastfile = i; 1705 } else { 1706 if (newfdp->fd_freefile == -1) 1707 newfdp->fd_freefile = i; 1708 } 1709 } 1710 newfdp->fd_cmask = fdp->fd_cmask; 1711 FILEDESC_SUNLOCK(fdp); 1712 FILEDESC_XLOCK(newfdp); 1713 for (i = 0; i <= newfdp->fd_lastfile; ++i) 1714 if (newfdp->fd_ofiles[i] != NULL) 1715 fdused(newfdp, i); 1716 if (newfdp->fd_freefile == -1) 1717 newfdp->fd_freefile = i; 1718 FILEDESC_XUNLOCK(newfdp); 1719 return (newfdp); 1720} 1721 1722/* 1723 * Release a filedesc structure. 1724 */ 1725void 1726fdfree(struct thread *td) 1727{ 1728 struct filedesc *fdp; 1729 struct file **fpp; 1730 int i, locked; 1731 struct filedesc_to_leader *fdtol; 1732 struct file *fp; 1733 struct vnode *cdir, *jdir, *rdir, *vp; 1734 struct flock lf; 1735 1736 /* Certain daemons might not have file descriptors. */ 1737 fdp = td->td_proc->p_fd; 1738 if (fdp == NULL) 1739 return; 1740 1741 /* Check for special need to clear POSIX style locks */ 1742 fdtol = td->td_proc->p_fdtol; 1743 if (fdtol != NULL) { 1744 FILEDESC_XLOCK(fdp); 1745 KASSERT(fdtol->fdl_refcount > 0, 1746 ("filedesc_to_refcount botch: fdl_refcount=%d", 1747 fdtol->fdl_refcount)); 1748 if (fdtol->fdl_refcount == 1 && 1749 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1750 for (i = 0, fpp = fdp->fd_ofiles; 1751 i <= fdp->fd_lastfile; 1752 i++, fpp++) { 1753 if (*fpp == NULL || 1754 (*fpp)->f_type != DTYPE_VNODE) 1755 continue; 1756 fp = *fpp; 1757 fhold(fp); 1758 FILEDESC_XUNLOCK(fdp); 1759 lf.l_whence = SEEK_SET; 1760 lf.l_start = 0; 1761 lf.l_len = 0; 1762 lf.l_type = F_UNLCK; 1763 vp = fp->f_vnode; 1764 locked = VFS_LOCK_GIANT(vp->v_mount); 1765 (void) VOP_ADVLOCK(vp, 1766 (caddr_t)td->td_proc-> 1767 p_leader, 1768 F_UNLCK, 1769 &lf, 1770 F_POSIX); 1771 VFS_UNLOCK_GIANT(locked); 1772 FILEDESC_XLOCK(fdp); 1773 fdrop(fp, td); 1774 fpp = fdp->fd_ofiles + i; 1775 } 1776 } 1777 retry: 1778 if (fdtol->fdl_refcount == 1) { 1779 if (fdp->fd_holdleaderscount > 0 && 1780 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1781 /* 1782 * close() or do_dup() has cleared a reference 1783 * in a shared file descriptor table. 1784 */ 1785 fdp->fd_holdleaderswakeup = 1; 1786 sx_sleep(&fdp->fd_holdleaderscount, 1787 FILEDESC_LOCK(fdp), PLOCK, "fdlhold", 0); 1788 goto retry; 1789 } 1790 if (fdtol->fdl_holdcount > 0) { 1791 /* 1792 * Ensure that fdtol->fdl_leader remains 1793 * valid in closef(). 1794 */ 1795 fdtol->fdl_wakeup = 1; 1796 sx_sleep(fdtol, FILEDESC_LOCK(fdp), PLOCK, 1797 "fdlhold", 0); 1798 goto retry; 1799 } 1800 } 1801 fdtol->fdl_refcount--; 1802 if (fdtol->fdl_refcount == 0 && 1803 fdtol->fdl_holdcount == 0) { 1804 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1805 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1806 } else 1807 fdtol = NULL; 1808 td->td_proc->p_fdtol = NULL; 1809 FILEDESC_XUNLOCK(fdp); 1810 if (fdtol != NULL) 1811 free(fdtol, M_FILEDESC_TO_LEADER); 1812 } 1813 FILEDESC_XLOCK(fdp); 1814 i = --fdp->fd_refcnt; 1815 FILEDESC_XUNLOCK(fdp); 1816 if (i > 0) 1817 return; 1818 1819 fpp = fdp->fd_ofiles; 1820 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) { 1821 if (*fpp) { 1822 FILEDESC_XLOCK(fdp); 1823 fp = *fpp; 1824 *fpp = NULL; 1825 FILEDESC_XUNLOCK(fdp); 1826 (void) closef(fp, td); 1827 } 1828 } 1829 FILEDESC_XLOCK(fdp); 1830 1831 /* XXX This should happen earlier. */ 1832 mtx_lock(&fdesc_mtx); 1833 td->td_proc->p_fd = NULL; 1834 mtx_unlock(&fdesc_mtx); 1835 1836 if (fdp->fd_nfiles > NDFILE) 1837 free(fdp->fd_ofiles, M_FILEDESC); 1838 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE)) 1839 free(fdp->fd_map, M_FILEDESC); 1840 1841 fdp->fd_nfiles = 0; 1842 1843 cdir = fdp->fd_cdir; 1844 fdp->fd_cdir = NULL; 1845 rdir = fdp->fd_rdir; 1846 fdp->fd_rdir = NULL; 1847 jdir = fdp->fd_jdir; 1848 fdp->fd_jdir = NULL; 1849 FILEDESC_XUNLOCK(fdp); 1850 1851 if (cdir) { 1852 locked = VFS_LOCK_GIANT(cdir->v_mount); 1853 vrele(cdir); 1854 VFS_UNLOCK_GIANT(locked); 1855 } 1856 if (rdir) { 1857 locked = VFS_LOCK_GIANT(rdir->v_mount); 1858 vrele(rdir); 1859 VFS_UNLOCK_GIANT(locked); 1860 } 1861 if (jdir) { 1862 locked = VFS_LOCK_GIANT(jdir->v_mount); 1863 vrele(jdir); 1864 VFS_UNLOCK_GIANT(locked); 1865 } 1866 1867 fddrop(fdp); 1868} 1869 1870/* 1871 * For setugid programs, we don't want to people to use that setugidness 1872 * to generate error messages which write to a file which otherwise would 1873 * otherwise be off-limits to the process. We check for filesystems where 1874 * the vnode can change out from under us after execve (like [lin]procfs). 1875 * 1876 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 1877 * sufficient. We also don't check for setugidness since we know we are. 1878 */ 1879static int 1880is_unsafe(struct file *fp) 1881{ 1882 if (fp->f_type == DTYPE_VNODE) { 1883 struct vnode *vp = fp->f_vnode; 1884 1885 if ((vp->v_vflag & VV_PROCDEP) != 0) 1886 return (1); 1887 } 1888 return (0); 1889} 1890 1891/* 1892 * Make this setguid thing safe, if at all possible. 1893 */ 1894void 1895setugidsafety(struct thread *td) 1896{ 1897 struct filedesc *fdp; 1898 int i; 1899 1900 /* Certain daemons might not have file descriptors. */ 1901 fdp = td->td_proc->p_fd; 1902 if (fdp == NULL) 1903 return; 1904 1905 /* 1906 * Note: fdp->fd_ofiles may be reallocated out from under us while 1907 * we are blocked in a close. Be careful! 1908 */ 1909 FILEDESC_XLOCK(fdp); 1910 for (i = 0; i <= fdp->fd_lastfile; i++) { 1911 if (i > 2) 1912 break; 1913 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) { 1914 struct file *fp; 1915 1916 knote_fdclose(td, i); 1917 /* 1918 * NULL-out descriptor prior to close to avoid 1919 * a race while close blocks. 1920 */ 1921 fp = fdp->fd_ofiles[i]; 1922 fdp->fd_ofiles[i] = NULL; 1923 fdp->fd_ofileflags[i] = 0; 1924 fdunused(fdp, i); 1925 FILEDESC_XUNLOCK(fdp); 1926 (void) closef(fp, td); 1927 FILEDESC_XLOCK(fdp); 1928 } 1929 } 1930 FILEDESC_XUNLOCK(fdp); 1931} 1932 1933/* 1934 * If a specific file object occupies a specific file descriptor, close the 1935 * file descriptor entry and drop a reference on the file object. This is a 1936 * convenience function to handle a subsequent error in a function that calls 1937 * falloc() that handles the race that another thread might have closed the 1938 * file descriptor out from under the thread creating the file object. 1939 */ 1940void 1941fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td) 1942{ 1943 1944 FILEDESC_XLOCK(fdp); 1945 if (fdp->fd_ofiles[idx] == fp) { 1946 fdp->fd_ofiles[idx] = NULL; 1947 fdunused(fdp, idx); 1948 FILEDESC_XUNLOCK(fdp); 1949 fdrop(fp, td); 1950 } else 1951 FILEDESC_XUNLOCK(fdp); 1952} 1953 1954/* 1955 * Close any files on exec? 1956 */ 1957void 1958fdcloseexec(struct thread *td) 1959{ 1960 struct filedesc *fdp; 1961 int i; 1962 1963 /* Certain daemons might not have file descriptors. */ 1964 fdp = td->td_proc->p_fd; 1965 if (fdp == NULL) 1966 return; 1967 1968 FILEDESC_XLOCK(fdp); 1969 1970 /* 1971 * We cannot cache fd_ofiles or fd_ofileflags since operations 1972 * may block and rip them out from under us. 1973 */ 1974 for (i = 0; i <= fdp->fd_lastfile; i++) { 1975 if (fdp->fd_ofiles[i] != NULL && 1976 (fdp->fd_ofiles[i]->f_type == DTYPE_MQUEUE || 1977 (fdp->fd_ofileflags[i] & UF_EXCLOSE))) { 1978 struct file *fp; 1979 1980 knote_fdclose(td, i); 1981 /* 1982 * NULL-out descriptor prior to close to avoid 1983 * a race while close blocks. 1984 */ 1985 fp = fdp->fd_ofiles[i]; 1986 fdp->fd_ofiles[i] = NULL; 1987 fdp->fd_ofileflags[i] = 0; 1988 fdunused(fdp, i); 1989 if (fp->f_type == DTYPE_MQUEUE) 1990 mq_fdclose(td, i, fp); 1991 FILEDESC_XUNLOCK(fdp); 1992 (void) closef(fp, td); 1993 FILEDESC_XLOCK(fdp); 1994 } 1995 } 1996 FILEDESC_XUNLOCK(fdp); 1997} 1998 1999/* 2000 * It is unsafe for set[ug]id processes to be started with file 2001 * descriptors 0..2 closed, as these descriptors are given implicit 2002 * significance in the Standard C library. fdcheckstd() will create a 2003 * descriptor referencing /dev/null for each of stdin, stdout, and 2004 * stderr that is not already open. 2005 */ 2006int 2007fdcheckstd(struct thread *td) 2008{ 2009 struct filedesc *fdp; 2010 register_t retval, save; 2011 int i, error, devnull; 2012 2013 fdp = td->td_proc->p_fd; 2014 if (fdp == NULL) 2015 return (0); 2016 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 2017 devnull = -1; 2018 error = 0; 2019 for (i = 0; i < 3; i++) { 2020 if (fdp->fd_ofiles[i] != NULL) 2021 continue; 2022 if (devnull < 0) { 2023 save = td->td_retval[0]; 2024 error = kern_open(td, "/dev/null", UIO_SYSSPACE, 2025 O_RDWR, 0); 2026 devnull = td->td_retval[0]; 2027 KASSERT(devnull == i, ("oof, we didn't get our fd")); 2028 td->td_retval[0] = save; 2029 if (error) 2030 break; 2031 } else { 2032 error = do_dup(td, DUP_FIXED, devnull, i, &retval); 2033 if (error != 0) 2034 break; 2035 } 2036 } 2037 return (error); 2038} 2039 2040/* 2041 * Internal form of close. Decrement reference count on file structure. 2042 * Note: td may be NULL when closing a file that was being passed in a 2043 * message. 2044 * 2045 * XXXRW: Giant is not required for the caller, but often will be held; this 2046 * makes it moderately likely the Giant will be recursed in the VFS case. 2047 */ 2048int 2049closef(struct file *fp, struct thread *td) 2050{ 2051 struct vnode *vp; 2052 struct flock lf; 2053 struct filedesc_to_leader *fdtol; 2054 struct filedesc *fdp; 2055 2056 /* 2057 * POSIX record locking dictates that any close releases ALL 2058 * locks owned by this process. This is handled by setting 2059 * a flag in the unlock to free ONLY locks obeying POSIX 2060 * semantics, and not to free BSD-style file locks. 2061 * If the descriptor was in a message, POSIX-style locks 2062 * aren't passed with the descriptor, and the thread pointer 2063 * will be NULL. Callers should be careful only to pass a 2064 * NULL thread pointer when there really is no owning 2065 * context that might have locks, or the locks will be 2066 * leaked. 2067 */ 2068 if (fp->f_type == DTYPE_VNODE && td != NULL) { 2069 int vfslocked; 2070 2071 vp = fp->f_vnode; 2072 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 2073 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 2074 lf.l_whence = SEEK_SET; 2075 lf.l_start = 0; 2076 lf.l_len = 0; 2077 lf.l_type = F_UNLCK; 2078 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader, 2079 F_UNLCK, &lf, F_POSIX); 2080 } 2081 fdtol = td->td_proc->p_fdtol; 2082 if (fdtol != NULL) { 2083 /* 2084 * Handle special case where file descriptor table is 2085 * shared between multiple process leaders. 2086 */ 2087 fdp = td->td_proc->p_fd; 2088 FILEDESC_XLOCK(fdp); 2089 for (fdtol = fdtol->fdl_next; 2090 fdtol != td->td_proc->p_fdtol; 2091 fdtol = fdtol->fdl_next) { 2092 if ((fdtol->fdl_leader->p_flag & 2093 P_ADVLOCK) == 0) 2094 continue; 2095 fdtol->fdl_holdcount++; 2096 FILEDESC_XUNLOCK(fdp); 2097 lf.l_whence = SEEK_SET; 2098 lf.l_start = 0; 2099 lf.l_len = 0; 2100 lf.l_type = F_UNLCK; 2101 vp = fp->f_vnode; 2102 (void) VOP_ADVLOCK(vp, 2103 (caddr_t)fdtol->fdl_leader, 2104 F_UNLCK, &lf, F_POSIX); 2105 FILEDESC_XLOCK(fdp); 2106 fdtol->fdl_holdcount--; 2107 if (fdtol->fdl_holdcount == 0 && 2108 fdtol->fdl_wakeup != 0) { 2109 fdtol->fdl_wakeup = 0; 2110 wakeup(fdtol); 2111 } 2112 } 2113 FILEDESC_XUNLOCK(fdp); 2114 } 2115 VFS_UNLOCK_GIANT(vfslocked); 2116 } 2117 return (fdrop(fp, td)); 2118} 2119 2120/* 2121 * Initialize the file pointer with the specified properties. 2122 * 2123 * The ops are set with release semantics to be certain that the flags, type, 2124 * and data are visible when ops is. This is to prevent ops methods from being 2125 * called with bad data. 2126 */ 2127void 2128finit(struct file *fp, u_int flag, short type, void *data, struct fileops *ops) 2129{ 2130 fp->f_data = data; 2131 fp->f_flag = flag; 2132 fp->f_type = type; 2133 atomic_store_rel_ptr((volatile uintptr_t *)&fp->f_ops, (uintptr_t)ops); 2134} 2135 2136struct file * 2137fget_unlocked(struct filedesc *fdp, int fd) 2138{ 2139 struct file *fp; 2140 u_int count; 2141 2142 if (fd < 0 || fd >= fdp->fd_nfiles) 2143 return (NULL); 2144 /* 2145 * Fetch the descriptor locklessly. We avoid fdrop() races by 2146 * never raising a refcount above 0. To accomplish this we have 2147 * to use a cmpset loop rather than an atomic_add. The descriptor 2148 * must be re-verified once we acquire a reference to be certain 2149 * that the identity is still correct and we did not lose a race 2150 * due to preemption. 2151 */ 2152 for (;;) { 2153 fp = fdp->fd_ofiles[fd]; 2154 if (fp == NULL) 2155 break; 2156 count = fp->f_count; 2157 if (count == 0) 2158 continue; 2159 /* 2160 * Use an acquire barrier to prevent caching of fd_ofiles 2161 * so it is refreshed for verification. 2162 */ 2163 if (atomic_cmpset_acq_int(&fp->f_count, count, count + 1) != 1) 2164 continue; 2165 if (fp == fdp->fd_ofiles[fd]) 2166 break; 2167 fdrop(fp, curthread); 2168 } 2169 2170 return (fp); 2171} 2172 2173/* 2174 * Extract the file pointer associated with the specified descriptor for the 2175 * current user process. 2176 * 2177 * If the descriptor doesn't exist or doesn't match 'flags', EBADF is 2178 * returned. 2179 * 2180 * If an error occured the non-zero error is returned and *fpp is set to 2181 * NULL. Otherwise *fpp is held and set and zero is returned. Caller is 2182 * responsible for fdrop(). 2183 */ 2184static __inline int 2185_fget(struct thread *td, int fd, struct file **fpp, int flags) 2186{ 2187 struct filedesc *fdp; 2188 struct file *fp; 2189 2190 *fpp = NULL; 2191 if (td == NULL || (fdp = td->td_proc->p_fd) == NULL) 2192 return (EBADF); 2193 if ((fp = fget_unlocked(fdp, fd)) == NULL) 2194 return (EBADF); 2195 if (fp->f_ops == &badfileops) { 2196 fdrop(fp, td); 2197 return (EBADF); 2198 } 2199 /* 2200 * FREAD and FWRITE failure return EBADF as per POSIX. 2201 * 2202 * Only one flag, or 0, may be specified. 2203 */ 2204 if ((flags == FREAD && (fp->f_flag & FREAD) == 0) || 2205 (flags == FWRITE && (fp->f_flag & FWRITE) == 0)) { 2206 fdrop(fp, td); 2207 return (EBADF); 2208 } 2209 *fpp = fp; 2210 return (0); 2211} 2212 2213int 2214fget(struct thread *td, int fd, struct file **fpp) 2215{ 2216 2217 return(_fget(td, fd, fpp, 0)); 2218} 2219 2220int 2221fget_read(struct thread *td, int fd, struct file **fpp) 2222{ 2223 2224 return(_fget(td, fd, fpp, FREAD)); 2225} 2226 2227int 2228fget_write(struct thread *td, int fd, struct file **fpp) 2229{ 2230 2231 return(_fget(td, fd, fpp, FWRITE)); 2232} 2233 2234/* 2235 * Like fget() but loads the underlying vnode, or returns an error if the 2236 * descriptor does not represent a vnode. Note that pipes use vnodes but 2237 * never have VM objects. The returned vnode will be vref()'d. 2238 * 2239 * XXX: what about the unused flags ? 2240 */ 2241static __inline int 2242_fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags) 2243{ 2244 struct file *fp; 2245 int error; 2246 2247 *vpp = NULL; 2248 if ((error = _fget(td, fd, &fp, flags)) != 0) 2249 return (error); 2250 if (fp->f_vnode == NULL) { 2251 error = EINVAL; 2252 } else { 2253 *vpp = fp->f_vnode; 2254 vref(*vpp); 2255 } 2256 fdrop(fp, td); 2257 2258 return (error); 2259} 2260 2261int 2262fgetvp(struct thread *td, int fd, struct vnode **vpp) 2263{ 2264 2265 return (_fgetvp(td, fd, vpp, 0)); 2266} 2267 2268int 2269fgetvp_read(struct thread *td, int fd, struct vnode **vpp) 2270{ 2271 2272 return (_fgetvp(td, fd, vpp, FREAD)); 2273} 2274 2275#ifdef notyet 2276int 2277fgetvp_write(struct thread *td, int fd, struct vnode **vpp) 2278{ 2279 2280 return (_fgetvp(td, fd, vpp, FWRITE)); 2281} 2282#endif 2283 2284/* 2285 * Like fget() but loads the underlying socket, or returns an error if the 2286 * descriptor does not represent a socket. 2287 * 2288 * We bump the ref count on the returned socket. XXX Also obtain the SX lock 2289 * in the future. 2290 * 2291 * Note: fgetsock() and fputsock() are deprecated, as consumers should rely 2292 * on their file descriptor reference to prevent the socket from being free'd 2293 * during use. 2294 */ 2295int 2296fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp) 2297{ 2298 struct file *fp; 2299 int error; 2300 2301 *spp = NULL; 2302 if (fflagp != NULL) 2303 *fflagp = 0; 2304 if ((error = _fget(td, fd, &fp, 0)) != 0) 2305 return (error); 2306 if (fp->f_type != DTYPE_SOCKET) { 2307 error = ENOTSOCK; 2308 } else { 2309 *spp = fp->f_data; 2310 if (fflagp) 2311 *fflagp = fp->f_flag; 2312 SOCK_LOCK(*spp); 2313 soref(*spp); 2314 SOCK_UNLOCK(*spp); 2315 } 2316 fdrop(fp, td); 2317 2318 return (error); 2319} 2320 2321/* 2322 * Drop the reference count on the socket and XXX release the SX lock in the 2323 * future. The last reference closes the socket. 2324 * 2325 * Note: fputsock() is deprecated, see comment for fgetsock(). 2326 */ 2327void 2328fputsock(struct socket *so) 2329{ 2330 2331 ACCEPT_LOCK(); 2332 SOCK_LOCK(so); 2333 sorele(so); 2334} 2335 2336/* 2337 * Handle the last reference to a file being closed. 2338 */ 2339int 2340_fdrop(struct file *fp, struct thread *td) 2341{ 2342 int error; 2343 2344 error = 0; 2345 if (fp->f_count != 0) 2346 panic("fdrop: count %d", fp->f_count); 2347 if (fp->f_ops != &badfileops) 2348 error = fo_close(fp, td); 2349 /* 2350 * The f_cdevpriv cannot be assigned non-NULL value while we 2351 * are destroying the file. 2352 */ 2353 if (fp->f_cdevpriv != NULL) 2354 devfs_fpdrop(fp); 2355 atomic_subtract_int(&openfiles, 1); 2356 crfree(fp->f_cred); 2357 uma_zfree(file_zone, fp); 2358 2359 return (error); 2360} 2361 2362/* 2363 * Apply an advisory lock on a file descriptor. 2364 * 2365 * Just attempt to get a record lock of the requested type on the entire file 2366 * (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2367 */ 2368#ifndef _SYS_SYSPROTO_H_ 2369struct flock_args { 2370 int fd; 2371 int how; 2372}; 2373#endif 2374/* ARGSUSED */ 2375int 2376flock(struct thread *td, struct flock_args *uap) 2377{ 2378 struct file *fp; 2379 struct vnode *vp; 2380 struct flock lf; 2381 int vfslocked; 2382 int error; 2383 2384 if ((error = fget(td, uap->fd, &fp)) != 0) 2385 return (error); 2386 if (fp->f_type != DTYPE_VNODE) { 2387 fdrop(fp, td); 2388 return (EOPNOTSUPP); 2389 } 2390 2391 vp = fp->f_vnode; 2392 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 2393 lf.l_whence = SEEK_SET; 2394 lf.l_start = 0; 2395 lf.l_len = 0; 2396 if (uap->how & LOCK_UN) { 2397 lf.l_type = F_UNLCK; 2398 atomic_clear_int(&fp->f_flag, FHASLOCK); 2399 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 2400 goto done2; 2401 } 2402 if (uap->how & LOCK_EX) 2403 lf.l_type = F_WRLCK; 2404 else if (uap->how & LOCK_SH) 2405 lf.l_type = F_RDLCK; 2406 else { 2407 error = EBADF; 2408 goto done2; 2409 } 2410 atomic_set_int(&fp->f_flag, FHASLOCK); 2411 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 2412 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT); 2413done2: 2414 fdrop(fp, td); 2415 VFS_UNLOCK_GIANT(vfslocked); 2416 return (error); 2417} 2418/* 2419 * Duplicate the specified descriptor to a free descriptor. 2420 */ 2421int 2422dupfdopen(struct thread *td, struct filedesc *fdp, int indx, int dfd, int mode, int error) 2423{ 2424 struct file *wfp; 2425 struct file *fp; 2426 2427 /* 2428 * If the to-be-dup'd fd number is greater than the allowed number 2429 * of file descriptors, or the fd to be dup'd has already been 2430 * closed, then reject. 2431 */ 2432 FILEDESC_XLOCK(fdp); 2433 if (dfd < 0 || dfd >= fdp->fd_nfiles || 2434 (wfp = fdp->fd_ofiles[dfd]) == NULL) { 2435 FILEDESC_XUNLOCK(fdp); 2436 return (EBADF); 2437 } 2438 2439 /* 2440 * There are two cases of interest here. 2441 * 2442 * For ENODEV simply dup (dfd) to file descriptor (indx) and return. 2443 * 2444 * For ENXIO steal away the file structure from (dfd) and store it in 2445 * (indx). (dfd) is effectively closed by this operation. 2446 * 2447 * Any other error code is just returned. 2448 */ 2449 switch (error) { 2450 case ENODEV: 2451 /* 2452 * Check that the mode the file is being opened for is a 2453 * subset of the mode of the existing descriptor. 2454 */ 2455 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2456 FILEDESC_XUNLOCK(fdp); 2457 return (EACCES); 2458 } 2459 fp = fdp->fd_ofiles[indx]; 2460 fdp->fd_ofiles[indx] = wfp; 2461 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2462 if (fp == NULL) 2463 fdused(fdp, indx); 2464 fhold(wfp); 2465 FILEDESC_XUNLOCK(fdp); 2466 if (fp != NULL) 2467 /* 2468 * We now own the reference to fp that the ofiles[] 2469 * array used to own. Release it. 2470 */ 2471 fdrop(fp, td); 2472 return (0); 2473 2474 case ENXIO: 2475 /* 2476 * Steal away the file pointer from dfd and stuff it into indx. 2477 */ 2478 fp = fdp->fd_ofiles[indx]; 2479 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd]; 2480 fdp->fd_ofiles[dfd] = NULL; 2481 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2482 fdp->fd_ofileflags[dfd] = 0; 2483 fdunused(fdp, dfd); 2484 if (fp == NULL) 2485 fdused(fdp, indx); 2486 FILEDESC_XUNLOCK(fdp); 2487 2488 /* 2489 * We now own the reference to fp that the ofiles[] array 2490 * used to own. Release it. 2491 */ 2492 if (fp != NULL) 2493 fdrop(fp, td); 2494 return (0); 2495 2496 default: 2497 FILEDESC_XUNLOCK(fdp); 2498 return (error); 2499 } 2500 /* NOTREACHED */ 2501} 2502 2503/* 2504 * Scan all active processes and prisons to see if any of them have a current 2505 * or root directory of `olddp'. If so, replace them with the new mount point. 2506 */ 2507void 2508mountcheckdirs(struct vnode *olddp, struct vnode *newdp) 2509{ 2510 struct filedesc *fdp; 2511 struct prison *pr; 2512 struct proc *p; 2513 int nrele; 2514 2515 if (vrefcnt(olddp) == 1) 2516 return; 2517 nrele = 0; 2518 sx_slock(&allproc_lock); 2519 FOREACH_PROC_IN_SYSTEM(p) { 2520 fdp = fdhold(p); 2521 if (fdp == NULL) 2522 continue; 2523 FILEDESC_XLOCK(fdp); 2524 if (fdp->fd_cdir == olddp) { 2525 vref(newdp); 2526 fdp->fd_cdir = newdp; 2527 nrele++; 2528 } 2529 if (fdp->fd_rdir == olddp) { 2530 vref(newdp); 2531 fdp->fd_rdir = newdp; 2532 nrele++; 2533 } 2534 if (fdp->fd_jdir == olddp) { 2535 vref(newdp); 2536 fdp->fd_jdir = newdp; 2537 nrele++; 2538 } 2539 FILEDESC_XUNLOCK(fdp); 2540 fddrop(fdp); 2541 } 2542 sx_sunlock(&allproc_lock); 2543 if (rootvnode == olddp) { 2544 vref(newdp); 2545 rootvnode = newdp; 2546 nrele++; 2547 } 2548 mtx_lock(&prison0.pr_mtx); 2549 if (prison0.pr_root == olddp) { 2550 vref(newdp); 2551 prison0.pr_root = newdp; 2552 nrele++; 2553 } 2554 mtx_unlock(&prison0.pr_mtx); 2555 sx_slock(&allprison_lock); 2556 TAILQ_FOREACH(pr, &allprison, pr_list) { 2557 mtx_lock(&pr->pr_mtx); 2558 if (pr->pr_root == olddp) { 2559 vref(newdp); 2560 pr->pr_root = newdp; 2561 nrele++; 2562 } 2563 mtx_unlock(&pr->pr_mtx); 2564 } 2565 sx_sunlock(&allprison_lock); 2566 while (nrele--) 2567 vrele(olddp); 2568} 2569 2570struct filedesc_to_leader * 2571filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader) 2572{ 2573 struct filedesc_to_leader *fdtol; 2574 2575 fdtol = malloc(sizeof(struct filedesc_to_leader), 2576 M_FILEDESC_TO_LEADER, 2577 M_WAITOK); 2578 fdtol->fdl_refcount = 1; 2579 fdtol->fdl_holdcount = 0; 2580 fdtol->fdl_wakeup = 0; 2581 fdtol->fdl_leader = leader; 2582 if (old != NULL) { 2583 FILEDESC_XLOCK(fdp); 2584 fdtol->fdl_next = old->fdl_next; 2585 fdtol->fdl_prev = old; 2586 old->fdl_next = fdtol; 2587 fdtol->fdl_next->fdl_prev = fdtol; 2588 FILEDESC_XUNLOCK(fdp); 2589 } else { 2590 fdtol->fdl_next = fdtol; 2591 fdtol->fdl_prev = fdtol; 2592 } 2593 return (fdtol); 2594} 2595 2596/* 2597 * Get file structures globally. 2598 */ 2599static int 2600sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2601{ 2602 struct xfile xf; 2603 struct filedesc *fdp; 2604 struct file *fp; 2605 struct proc *p; 2606 int error, n; 2607 2608 error = sysctl_wire_old_buffer(req, 0); 2609 if (error != 0) 2610 return (error); 2611 if (req->oldptr == NULL) { 2612 n = 0; 2613 sx_slock(&allproc_lock); 2614 FOREACH_PROC_IN_SYSTEM(p) { 2615 if (p->p_state == PRS_NEW) 2616 continue; 2617 fdp = fdhold(p); 2618 if (fdp == NULL) 2619 continue; 2620 /* overestimates sparse tables. */ 2621 if (fdp->fd_lastfile > 0) 2622 n += fdp->fd_lastfile; 2623 fddrop(fdp); 2624 } 2625 sx_sunlock(&allproc_lock); 2626 return (SYSCTL_OUT(req, 0, n * sizeof(xf))); 2627 } 2628 error = 0; 2629 bzero(&xf, sizeof(xf)); 2630 xf.xf_size = sizeof(xf); 2631 sx_slock(&allproc_lock); 2632 FOREACH_PROC_IN_SYSTEM(p) { 2633 if (p->p_state == PRS_NEW) 2634 continue; 2635 PROC_LOCK(p); 2636 if (p_cansee(req->td, p) != 0) { 2637 PROC_UNLOCK(p); 2638 continue; 2639 } 2640 xf.xf_pid = p->p_pid; 2641 xf.xf_uid = p->p_ucred->cr_uid; 2642 PROC_UNLOCK(p); 2643 fdp = fdhold(p); 2644 if (fdp == NULL) 2645 continue; 2646 FILEDESC_SLOCK(fdp); 2647 for (n = 0; fdp->fd_refcnt > 0 && n < fdp->fd_nfiles; ++n) { 2648 if ((fp = fdp->fd_ofiles[n]) == NULL) 2649 continue; 2650 xf.xf_fd = n; 2651 xf.xf_file = fp; 2652 xf.xf_data = fp->f_data; 2653 xf.xf_vnode = fp->f_vnode; 2654 xf.xf_type = fp->f_type; 2655 xf.xf_count = fp->f_count; 2656 xf.xf_msgcount = 0; 2657 xf.xf_offset = fp->f_offset; 2658 xf.xf_flag = fp->f_flag; 2659 error = SYSCTL_OUT(req, &xf, sizeof(xf)); 2660 if (error) 2661 break; 2662 } 2663 FILEDESC_SUNLOCK(fdp); 2664 fddrop(fdp); 2665 if (error) 2666 break; 2667 } 2668 sx_sunlock(&allproc_lock); 2669 return (error); 2670} 2671 2672SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2673 0, 0, sysctl_kern_file, "S,xfile", "Entire file table"); 2674 2675#ifdef KINFO_OFILE_SIZE 2676CTASSERT(sizeof(struct kinfo_ofile) == KINFO_OFILE_SIZE); 2677#endif 2678 2679#ifdef COMPAT_FREEBSD7 2680static int 2681export_vnode_for_osysctl(struct vnode *vp, int type, 2682 struct kinfo_ofile *kif, struct filedesc *fdp, struct sysctl_req *req) 2683{ 2684 int error; 2685 char *fullpath, *freepath; 2686 int vfslocked; 2687 2688 bzero(kif, sizeof(*kif)); 2689 kif->kf_structsize = sizeof(*kif); 2690 2691 vref(vp); 2692 kif->kf_fd = type; 2693 kif->kf_type = KF_TYPE_VNODE; 2694 /* This function only handles directories. */ 2695 if (vp->v_type != VDIR) { 2696 vrele(vp); 2697 return (ENOTDIR); 2698 } 2699 kif->kf_vnode_type = KF_VTYPE_VDIR; 2700 2701 /* 2702 * This is not a true file descriptor, so we set a bogus refcount 2703 * and offset to indicate these fields should be ignored. 2704 */ 2705 kif->kf_ref_count = -1; 2706 kif->kf_offset = -1; 2707 2708 freepath = NULL; 2709 fullpath = "-"; 2710 FILEDESC_SUNLOCK(fdp); 2711 vn_fullpath(curthread, vp, &fullpath, &freepath); 2712 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 2713 vrele(vp); 2714 VFS_UNLOCK_GIANT(vfslocked); 2715 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2716 if (freepath != NULL) 2717 free(freepath, M_TEMP); 2718 error = SYSCTL_OUT(req, kif, sizeof(*kif)); 2719 FILEDESC_SLOCK(fdp); 2720 return (error); 2721} 2722 2723/* 2724 * Get per-process file descriptors for use by procstat(1), et al. 2725 */ 2726static int 2727sysctl_kern_proc_ofiledesc(SYSCTL_HANDLER_ARGS) 2728{ 2729 char *fullpath, *freepath; 2730 struct kinfo_ofile *kif; 2731 struct filedesc *fdp; 2732 int error, i, *name; 2733 struct socket *so; 2734 struct vnode *vp; 2735 struct file *fp; 2736 struct proc *p; 2737 struct tty *tp; 2738 int vfslocked; 2739 2740 name = (int *)arg1; 2741 if ((p = pfind((pid_t)name[0])) == NULL) 2742 return (ESRCH); 2743 if ((error = p_candebug(curthread, p))) { 2744 PROC_UNLOCK(p); 2745 return (error); 2746 } 2747 fdp = fdhold(p); 2748 PROC_UNLOCK(p); 2749 if (fdp == NULL) 2750 return (ENOENT); 2751 kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK); 2752 FILEDESC_SLOCK(fdp); 2753 if (fdp->fd_cdir != NULL) 2754 export_vnode_for_osysctl(fdp->fd_cdir, KF_FD_TYPE_CWD, kif, 2755 fdp, req); 2756 if (fdp->fd_rdir != NULL) 2757 export_vnode_for_osysctl(fdp->fd_rdir, KF_FD_TYPE_ROOT, kif, 2758 fdp, req); 2759 if (fdp->fd_jdir != NULL) 2760 export_vnode_for_osysctl(fdp->fd_jdir, KF_FD_TYPE_JAIL, kif, 2761 fdp, req); 2762 for (i = 0; i < fdp->fd_nfiles; i++) { 2763 if ((fp = fdp->fd_ofiles[i]) == NULL) 2764 continue; 2765 bzero(kif, sizeof(*kif)); 2766 kif->kf_structsize = sizeof(*kif); 2767 vp = NULL; 2768 so = NULL; 2769 tp = NULL; 2770 kif->kf_fd = i; 2771 switch (fp->f_type) { 2772 case DTYPE_VNODE: 2773 kif->kf_type = KF_TYPE_VNODE; 2774 vp = fp->f_vnode; 2775 break; 2776 2777 case DTYPE_SOCKET: 2778 kif->kf_type = KF_TYPE_SOCKET; 2779 so = fp->f_data; 2780 break; 2781 2782 case DTYPE_PIPE: 2783 kif->kf_type = KF_TYPE_PIPE; 2784 break; 2785 2786 case DTYPE_FIFO: 2787 kif->kf_type = KF_TYPE_FIFO; 2788 vp = fp->f_vnode; 2789 break; 2790 2791 case DTYPE_KQUEUE: 2792 kif->kf_type = KF_TYPE_KQUEUE; 2793 break; 2794 2795 case DTYPE_CRYPTO: 2796 kif->kf_type = KF_TYPE_CRYPTO; 2797 break; 2798 2799 case DTYPE_MQUEUE: 2800 kif->kf_type = KF_TYPE_MQUEUE; 2801 break; 2802 2803 case DTYPE_SHM: 2804 kif->kf_type = KF_TYPE_SHM; 2805 break; 2806 2807 case DTYPE_SEM: 2808 kif->kf_type = KF_TYPE_SEM; 2809 break; 2810 2811 case DTYPE_PTS: 2812 kif->kf_type = KF_TYPE_PTS; 2813 tp = fp->f_data; 2814 break; 2815 2816 default: 2817 kif->kf_type = KF_TYPE_UNKNOWN; 2818 break; 2819 } 2820 kif->kf_ref_count = fp->f_count; 2821 if (fp->f_flag & FREAD) 2822 kif->kf_flags |= KF_FLAG_READ; 2823 if (fp->f_flag & FWRITE) 2824 kif->kf_flags |= KF_FLAG_WRITE; 2825 if (fp->f_flag & FAPPEND) 2826 kif->kf_flags |= KF_FLAG_APPEND; 2827 if (fp->f_flag & FASYNC) 2828 kif->kf_flags |= KF_FLAG_ASYNC; 2829 if (fp->f_flag & FFSYNC) 2830 kif->kf_flags |= KF_FLAG_FSYNC; 2831 if (fp->f_flag & FNONBLOCK) 2832 kif->kf_flags |= KF_FLAG_NONBLOCK; 2833 if (fp->f_flag & O_DIRECT) 2834 kif->kf_flags |= KF_FLAG_DIRECT; 2835 if (fp->f_flag & FHASLOCK) 2836 kif->kf_flags |= KF_FLAG_HASLOCK; 2837 kif->kf_offset = fp->f_offset; 2838 if (vp != NULL) { 2839 vref(vp); 2840 switch (vp->v_type) { 2841 case VNON: 2842 kif->kf_vnode_type = KF_VTYPE_VNON; 2843 break; 2844 case VREG: 2845 kif->kf_vnode_type = KF_VTYPE_VREG; 2846 break; 2847 case VDIR: 2848 kif->kf_vnode_type = KF_VTYPE_VDIR; 2849 break; 2850 case VBLK: 2851 kif->kf_vnode_type = KF_VTYPE_VBLK; 2852 break; 2853 case VCHR: 2854 kif->kf_vnode_type = KF_VTYPE_VCHR; 2855 break; 2856 case VLNK: 2857 kif->kf_vnode_type = KF_VTYPE_VLNK; 2858 break; 2859 case VSOCK: 2860 kif->kf_vnode_type = KF_VTYPE_VSOCK; 2861 break; 2862 case VFIFO: 2863 kif->kf_vnode_type = KF_VTYPE_VFIFO; 2864 break; 2865 case VBAD: 2866 kif->kf_vnode_type = KF_VTYPE_VBAD; 2867 break; 2868 default: 2869 kif->kf_vnode_type = KF_VTYPE_UNKNOWN; 2870 break; 2871 } 2872 /* 2873 * It is OK to drop the filedesc lock here as we will 2874 * re-validate and re-evaluate its properties when 2875 * the loop continues. 2876 */ 2877 freepath = NULL; 2878 fullpath = "-"; 2879 FILEDESC_SUNLOCK(fdp); 2880 vn_fullpath(curthread, vp, &fullpath, &freepath); 2881 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 2882 vrele(vp); 2883 VFS_UNLOCK_GIANT(vfslocked); 2884 strlcpy(kif->kf_path, fullpath, 2885 sizeof(kif->kf_path)); 2886 if (freepath != NULL) 2887 free(freepath, M_TEMP); 2888 FILEDESC_SLOCK(fdp); 2889 } 2890 if (so != NULL) { 2891 struct sockaddr *sa; 2892 2893 if (so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa) 2894 == 0 && sa->sa_len <= sizeof(kif->kf_sa_local)) { 2895 bcopy(sa, &kif->kf_sa_local, sa->sa_len); 2896 free(sa, M_SONAME); 2897 } 2898 if (so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa) 2899 == 00 && sa->sa_len <= sizeof(kif->kf_sa_peer)) { 2900 bcopy(sa, &kif->kf_sa_peer, sa->sa_len); 2901 free(sa, M_SONAME); 2902 } 2903 kif->kf_sock_domain = 2904 so->so_proto->pr_domain->dom_family; 2905 kif->kf_sock_type = so->so_type; 2906 kif->kf_sock_protocol = so->so_proto->pr_protocol; 2907 } 2908 if (tp != NULL) { 2909 strlcpy(kif->kf_path, tty_devname(tp), 2910 sizeof(kif->kf_path)); 2911 } 2912 error = SYSCTL_OUT(req, kif, sizeof(*kif)); 2913 if (error) 2914 break; 2915 } 2916 FILEDESC_SUNLOCK(fdp); 2917 fddrop(fdp); 2918 free(kif, M_TEMP); 2919 return (0); 2920} 2921 2922static SYSCTL_NODE(_kern_proc, KERN_PROC_OFILEDESC, ofiledesc, CTLFLAG_RD, 2923 sysctl_kern_proc_ofiledesc, "Process ofiledesc entries"); 2924#endif /* COMPAT_FREEBSD7 */ 2925 2926#ifdef KINFO_FILE_SIZE 2927CTASSERT(sizeof(struct kinfo_file) == KINFO_FILE_SIZE); 2928#endif 2929 2930static int 2931export_vnode_for_sysctl(struct vnode *vp, int type, 2932 struct kinfo_file *kif, struct filedesc *fdp, struct sysctl_req *req) 2933{ 2934 int error; 2935 char *fullpath, *freepath; 2936 int vfslocked; 2937 2938 bzero(kif, sizeof(*kif)); 2939 2940 vref(vp); 2941 kif->kf_fd = type; 2942 kif->kf_type = KF_TYPE_VNODE; 2943 /* This function only handles directories. */ 2944 if (vp->v_type != VDIR) { 2945 vrele(vp); 2946 return (ENOTDIR); 2947 } 2948 kif->kf_vnode_type = KF_VTYPE_VDIR; 2949 2950 /* 2951 * This is not a true file descriptor, so we set a bogus refcount 2952 * and offset to indicate these fields should be ignored. 2953 */ 2954 kif->kf_ref_count = -1; 2955 kif->kf_offset = -1; 2956 2957 freepath = NULL; 2958 fullpath = "-"; 2959 FILEDESC_SUNLOCK(fdp); 2960 vn_fullpath(curthread, vp, &fullpath, &freepath); 2961 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 2962 vrele(vp); 2963 VFS_UNLOCK_GIANT(vfslocked); 2964 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2965 if (freepath != NULL) 2966 free(freepath, M_TEMP); 2967 /* Pack record size down */ 2968 kif->kf_structsize = offsetof(struct kinfo_file, kf_path) + 2969 strlen(kif->kf_path) + 1; 2970 kif->kf_structsize = roundup(kif->kf_structsize, sizeof(uint64_t)); 2971 error = SYSCTL_OUT(req, kif, kif->kf_structsize); 2972 FILEDESC_SLOCK(fdp); 2973 return (error); 2974} 2975 2976/* 2977 * Get per-process file descriptors for use by procstat(1), et al. 2978 */ 2979static int 2980sysctl_kern_proc_filedesc(SYSCTL_HANDLER_ARGS) 2981{ 2982 char *fullpath, *freepath; 2983 struct kinfo_file *kif; 2984 struct filedesc *fdp; 2985 int error, i, *name; 2986 struct socket *so; 2987 struct vnode *vp; 2988 struct file *fp; 2989 struct proc *p; 2990 struct tty *tp; 2991 int vfslocked; 2992 size_t oldidx; 2993 2994 name = (int *)arg1; 2995 if ((p = pfind((pid_t)name[0])) == NULL) 2996 return (ESRCH); 2997 if ((error = p_candebug(curthread, p))) { 2998 PROC_UNLOCK(p); 2999 return (error); 3000 } 3001 fdp = fdhold(p); 3002 PROC_UNLOCK(p); 3003 if (fdp == NULL) 3004 return (ENOENT); 3005 kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK); 3006 FILEDESC_SLOCK(fdp); 3007 if (fdp->fd_cdir != NULL) 3008 export_vnode_for_sysctl(fdp->fd_cdir, KF_FD_TYPE_CWD, kif, 3009 fdp, req); 3010 if (fdp->fd_rdir != NULL) 3011 export_vnode_for_sysctl(fdp->fd_rdir, KF_FD_TYPE_ROOT, kif, 3012 fdp, req); 3013 if (fdp->fd_jdir != NULL) 3014 export_vnode_for_sysctl(fdp->fd_jdir, KF_FD_TYPE_JAIL, kif, 3015 fdp, req); 3016 for (i = 0; i < fdp->fd_nfiles; i++) { 3017 if ((fp = fdp->fd_ofiles[i]) == NULL) 3018 continue; 3019 bzero(kif, sizeof(*kif)); 3020 vp = NULL; 3021 so = NULL; 3022 tp = NULL; 3023 kif->kf_fd = i; 3024 switch (fp->f_type) { 3025 case DTYPE_VNODE: 3026 kif->kf_type = KF_TYPE_VNODE; 3027 vp = fp->f_vnode; 3028 break; 3029 3030 case DTYPE_SOCKET: 3031 kif->kf_type = KF_TYPE_SOCKET; 3032 so = fp->f_data; 3033 break; 3034 3035 case DTYPE_PIPE: 3036 kif->kf_type = KF_TYPE_PIPE; 3037 break; 3038 3039 case DTYPE_FIFO: 3040 kif->kf_type = KF_TYPE_FIFO; 3041 vp = fp->f_vnode; 3042 break; 3043 3044 case DTYPE_KQUEUE: 3045 kif->kf_type = KF_TYPE_KQUEUE; 3046 break; 3047 3048 case DTYPE_CRYPTO: 3049 kif->kf_type = KF_TYPE_CRYPTO; 3050 break; 3051 3052 case DTYPE_MQUEUE: 3053 kif->kf_type = KF_TYPE_MQUEUE; 3054 break; 3055 3056 case DTYPE_SHM: 3057 kif->kf_type = KF_TYPE_SHM; 3058 break; 3059 3060 case DTYPE_SEM: 3061 kif->kf_type = KF_TYPE_SEM; 3062 break; 3063 3064 case DTYPE_PTS: 3065 kif->kf_type = KF_TYPE_PTS; 3066 tp = fp->f_data; 3067 break; 3068 3069 default: 3070 kif->kf_type = KF_TYPE_UNKNOWN; 3071 break; 3072 } 3073 kif->kf_ref_count = fp->f_count; 3074 if (fp->f_flag & FREAD) 3075 kif->kf_flags |= KF_FLAG_READ; 3076 if (fp->f_flag & FWRITE) 3077 kif->kf_flags |= KF_FLAG_WRITE; 3078 if (fp->f_flag & FAPPEND) 3079 kif->kf_flags |= KF_FLAG_APPEND; 3080 if (fp->f_flag & FASYNC) 3081 kif->kf_flags |= KF_FLAG_ASYNC; 3082 if (fp->f_flag & FFSYNC) 3083 kif->kf_flags |= KF_FLAG_FSYNC; 3084 if (fp->f_flag & FNONBLOCK) 3085 kif->kf_flags |= KF_FLAG_NONBLOCK; 3086 if (fp->f_flag & O_DIRECT) 3087 kif->kf_flags |= KF_FLAG_DIRECT; 3088 if (fp->f_flag & FHASLOCK) 3089 kif->kf_flags |= KF_FLAG_HASLOCK; 3090 kif->kf_offset = fp->f_offset; 3091 if (vp != NULL) { 3092 vref(vp); 3093 switch (vp->v_type) { 3094 case VNON: 3095 kif->kf_vnode_type = KF_VTYPE_VNON; 3096 break; 3097 case VREG: 3098 kif->kf_vnode_type = KF_VTYPE_VREG; 3099 break; 3100 case VDIR: 3101 kif->kf_vnode_type = KF_VTYPE_VDIR; 3102 break; 3103 case VBLK: 3104 kif->kf_vnode_type = KF_VTYPE_VBLK; 3105 break; 3106 case VCHR: 3107 kif->kf_vnode_type = KF_VTYPE_VCHR; 3108 break; 3109 case VLNK: 3110 kif->kf_vnode_type = KF_VTYPE_VLNK; 3111 break; 3112 case VSOCK: 3113 kif->kf_vnode_type = KF_VTYPE_VSOCK; 3114 break; 3115 case VFIFO: 3116 kif->kf_vnode_type = KF_VTYPE_VFIFO; 3117 break; 3118 case VBAD: 3119 kif->kf_vnode_type = KF_VTYPE_VBAD; 3120 break; 3121 default: 3122 kif->kf_vnode_type = KF_VTYPE_UNKNOWN; 3123 break; 3124 } 3125 /* 3126 * It is OK to drop the filedesc lock here as we will 3127 * re-validate and re-evaluate its properties when 3128 * the loop continues. 3129 */ 3130 freepath = NULL; 3131 fullpath = "-"; 3132 FILEDESC_SUNLOCK(fdp); 3133 vn_fullpath(curthread, vp, &fullpath, &freepath); 3134 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 3135 vrele(vp); 3136 VFS_UNLOCK_GIANT(vfslocked); 3137 strlcpy(kif->kf_path, fullpath, 3138 sizeof(kif->kf_path)); 3139 if (freepath != NULL) 3140 free(freepath, M_TEMP); 3141 FILEDESC_SLOCK(fdp); 3142 } 3143 if (so != NULL) { 3144 struct sockaddr *sa; 3145 3146 if (so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa) 3147 == 0 && sa->sa_len <= sizeof(kif->kf_sa_local)) { 3148 bcopy(sa, &kif->kf_sa_local, sa->sa_len); 3149 free(sa, M_SONAME); 3150 } 3151 if (so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa) 3152 == 00 && sa->sa_len <= sizeof(kif->kf_sa_peer)) { 3153 bcopy(sa, &kif->kf_sa_peer, sa->sa_len); 3154 free(sa, M_SONAME); 3155 } 3156 kif->kf_sock_domain = 3157 so->so_proto->pr_domain->dom_family; 3158 kif->kf_sock_type = so->so_type; 3159 kif->kf_sock_protocol = so->so_proto->pr_protocol; 3160 } 3161 if (tp != NULL) { 3162 strlcpy(kif->kf_path, tty_devname(tp), 3163 sizeof(kif->kf_path)); 3164 } 3165 /* Pack record size down */ 3166 kif->kf_structsize = offsetof(struct kinfo_file, kf_path) + 3167 strlen(kif->kf_path) + 1; 3168 kif->kf_structsize = roundup(kif->kf_structsize, 3169 sizeof(uint64_t)); 3170 oldidx = req->oldidx; 3171 error = SYSCTL_OUT(req, kif, kif->kf_structsize); 3172 if (error) { 3173 if (error == ENOMEM) { 3174 /* 3175 * The hack to keep the ABI of sysctl 3176 * kern.proc.filedesc intact, but not 3177 * to account a partially copied 3178 * kinfo_file into the oldidx. 3179 */ 3180 req->oldidx = oldidx; 3181 error = 0; 3182 } 3183 break; 3184 } 3185 } 3186 FILEDESC_SUNLOCK(fdp); 3187 fddrop(fdp); 3188 free(kif, M_TEMP); 3189 return (error); 3190} 3191 3192static SYSCTL_NODE(_kern_proc, KERN_PROC_FILEDESC, filedesc, CTLFLAG_RD, 3193 sysctl_kern_proc_filedesc, "Process filedesc entries"); 3194 3195#ifdef DDB 3196/* 3197 * For the purposes of debugging, generate a human-readable string for the 3198 * file type. 3199 */ 3200static const char * 3201file_type_to_name(short type) 3202{ 3203 3204 switch (type) { 3205 case 0: 3206 return ("zero"); 3207 case DTYPE_VNODE: 3208 return ("vnod"); 3209 case DTYPE_SOCKET: 3210 return ("sock"); 3211 case DTYPE_PIPE: 3212 return ("pipe"); 3213 case DTYPE_FIFO: 3214 return ("fifo"); 3215 case DTYPE_KQUEUE: 3216 return ("kque"); 3217 case DTYPE_CRYPTO: 3218 return ("crpt"); 3219 case DTYPE_MQUEUE: 3220 return ("mque"); 3221 case DTYPE_SHM: 3222 return ("shm"); 3223 case DTYPE_SEM: 3224 return ("ksem"); 3225 default: 3226 return ("unkn"); 3227 } 3228} 3229 3230/* 3231 * For the purposes of debugging, identify a process (if any, perhaps one of 3232 * many) that references the passed file in its file descriptor array. Return 3233 * NULL if none. 3234 */ 3235static struct proc * 3236file_to_first_proc(struct file *fp) 3237{ 3238 struct filedesc *fdp; 3239 struct proc *p; 3240 int n; 3241 3242 FOREACH_PROC_IN_SYSTEM(p) { 3243 if (p->p_state == PRS_NEW) 3244 continue; 3245 fdp = p->p_fd; 3246 if (fdp == NULL) 3247 continue; 3248 for (n = 0; n < fdp->fd_nfiles; n++) { 3249 if (fp == fdp->fd_ofiles[n]) 3250 return (p); 3251 } 3252 } 3253 return (NULL); 3254} 3255 3256static void 3257db_print_file(struct file *fp, int header) 3258{ 3259 struct proc *p; 3260 3261 if (header) 3262 db_printf("%8s %4s %8s %8s %4s %5s %6s %8s %5s %12s\n", 3263 "File", "Type", "Data", "Flag", "GCFl", "Count", 3264 "MCount", "Vnode", "FPID", "FCmd"); 3265 p = file_to_first_proc(fp); 3266 db_printf("%8p %4s %8p %08x %04x %5d %6d %8p %5d %12s\n", fp, 3267 file_type_to_name(fp->f_type), fp->f_data, fp->f_flag, 3268 0, fp->f_count, 0, fp->f_vnode, 3269 p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-"); 3270} 3271 3272DB_SHOW_COMMAND(file, db_show_file) 3273{ 3274 struct file *fp; 3275 3276 if (!have_addr) { 3277 db_printf("usage: show file <addr>\n"); 3278 return; 3279 } 3280 fp = (struct file *)addr; 3281 db_print_file(fp, 1); 3282} 3283 3284DB_SHOW_COMMAND(files, db_show_files) 3285{ 3286 struct filedesc *fdp; 3287 struct file *fp; 3288 struct proc *p; 3289 int header; 3290 int n; 3291 3292 header = 1; 3293 FOREACH_PROC_IN_SYSTEM(p) { 3294 if (p->p_state == PRS_NEW) 3295 continue; 3296 if ((fdp = p->p_fd) == NULL) 3297 continue; 3298 for (n = 0; n < fdp->fd_nfiles; ++n) { 3299 if ((fp = fdp->fd_ofiles[n]) == NULL) 3300 continue; 3301 db_print_file(fp, header); 3302 header = 0; 3303 } 3304 } 3305} 3306#endif 3307 3308SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 3309 &maxfilesperproc, 0, "Maximum files allowed open per process"); 3310 3311SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 3312 &maxfiles, 0, "Maximum number of files"); 3313 3314SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 3315 __DEVOLATILE(int *, &openfiles), 0, "System-wide number of open files"); 3316 3317/* ARGSUSED*/ 3318static void 3319filelistinit(void *dummy) 3320{ 3321 3322 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL, 3323 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 3324 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF); 3325 mtx_init(&fdesc_mtx, "fdesc", NULL, MTX_DEF); 3326} 3327SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL); 3328 3329/*-------------------------------------------------------------------*/ 3330 3331static int 3332badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td) 3333{ 3334 3335 return (EBADF); 3336} 3337 3338static int 3339badfo_truncate(struct file *fp, off_t length, struct ucred *active_cred, struct thread *td) 3340{ 3341 3342 return (EINVAL); 3343} 3344 3345static int 3346badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, struct thread *td) 3347{ 3348 3349 return (EBADF); 3350} 3351 3352static int 3353badfo_poll(struct file *fp, int events, struct ucred *active_cred, struct thread *td) 3354{ 3355 3356 return (0); 3357} 3358 3359static int 3360badfo_kqfilter(struct file *fp, struct knote *kn) 3361{ 3362 3363 return (EBADF); 3364} 3365 3366static int 3367badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, struct thread *td) 3368{ 3369 3370 return (EBADF); 3371} 3372 3373static int 3374badfo_close(struct file *fp, struct thread *td) 3375{ 3376 3377 return (EBADF); 3378} 3379 3380struct fileops badfileops = { 3381 .fo_read = badfo_readwrite, 3382 .fo_write = badfo_readwrite, 3383 .fo_truncate = badfo_truncate, 3384 .fo_ioctl = badfo_ioctl, 3385 .fo_poll = badfo_poll, 3386 .fo_kqfilter = badfo_kqfilter, 3387 .fo_stat = badfo_stat, 3388 .fo_close = badfo_close, 3389}; 3390 3391 3392/*-------------------------------------------------------------------*/ 3393 3394/* 3395 * File Descriptor pseudo-device driver (/dev/fd/). 3396 * 3397 * Opening minor device N dup()s the file (if any) connected to file 3398 * descriptor N belonging to the calling process. Note that this driver 3399 * consists of only the ``open()'' routine, because all subsequent 3400 * references to this file will be direct to the other driver. 3401 * 3402 * XXX: we could give this one a cloning event handler if necessary. 3403 */ 3404 3405/* ARGSUSED */ 3406static int 3407fdopen(struct cdev *dev, int mode, int type, struct thread *td) 3408{ 3409 3410 /* 3411 * XXX Kludge: set curthread->td_dupfd to contain the value of the 3412 * the file descriptor being sought for duplication. The error 3413 * return ensures that the vnode for this device will be released 3414 * by vn_open. Open will detect this special error and take the 3415 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 3416 * will simply report the error. 3417 */ 3418 td->td_dupfd = dev2unit(dev); 3419 return (ENODEV); 3420} 3421 3422static struct cdevsw fildesc_cdevsw = { 3423 .d_version = D_VERSION, 3424 .d_open = fdopen, 3425 .d_name = "FD", 3426}; 3427 3428static void 3429fildesc_drvinit(void *unused) 3430{ 3431 struct cdev *dev; 3432 3433 dev = make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "fd/0"); 3434 make_dev_alias(dev, "stdin"); 3435 dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1"); 3436 make_dev_alias(dev, "stdout"); 3437 dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2"); 3438 make_dev_alias(dev, "stderr"); 3439} 3440 3441SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL); 3442