kern_descrip.c revision 134018
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 134018 2004-08-19 14:59:51Z rwatson $"); 39 40#include "opt_compat.h" 41 42#include <sys/param.h> 43#include <sys/limits.h> 44#include <sys/systm.h> 45#include <sys/syscallsubr.h> 46#include <sys/sysproto.h> 47#include <sys/conf.h> 48#include <sys/filedesc.h> 49#include <sys/lock.h> 50#include <sys/jail.h> 51#include <sys/kernel.h> 52#include <sys/limits.h> 53#include <sys/malloc.h> 54#include <sys/mutex.h> 55#include <sys/sysctl.h> 56#include <sys/vnode.h> 57#include <sys/mount.h> 58#include <sys/proc.h> 59#include <sys/namei.h> 60#include <sys/file.h> 61#include <sys/stat.h> 62#include <sys/filio.h> 63#include <sys/fcntl.h> 64#include <sys/unistd.h> 65#include <sys/resourcevar.h> 66#include <sys/event.h> 67#include <sys/sx.h> 68#include <sys/socketvar.h> 69#include <sys/signalvar.h> 70 71#include <vm/vm.h> 72#include <vm/vm_extern.h> 73#include <vm/uma.h> 74 75static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 76static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 77 "file desc to leader structures"); 78static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 79 80static uma_zone_t file_zone; 81 82static d_open_t fdopen; 83#define NUMFDESC 64 84 85#define CDEV_MAJOR 22 86static struct cdevsw fildesc_cdevsw = { 87 .d_version = D_VERSION, 88 .d_flags = D_NEEDGIANT, 89 .d_open = fdopen, 90 .d_name = "FD", 91 .d_maj = CDEV_MAJOR, 92}; 93 94/* How to treat 'new' parameter when allocating a fd for do_dup(). */ 95enum dup_type { DUP_VARIABLE, DUP_FIXED }; 96 97static int do_dup(struct thread *td, enum dup_type type, int old, int new, 98 register_t *retval); 99static int fd_first_free(struct filedesc *, int, int); 100static int fd_last_used(struct filedesc *, int, int); 101static void fdgrowtable(struct filedesc *, int); 102 103/* 104 * Descriptor management. 105 */ 106struct filelist filehead; /* head of list of open files */ 107int nfiles; /* actual number of open files */ 108struct sx filelist_lock; /* sx to protect filelist */ 109struct mtx sigio_lock; /* mtx to protect pointers to sigio */ 110 111/* 112 * Find the first zero bit in the given bitmap, starting at low and not 113 * exceeding size - 1. 114 */ 115static int 116fd_first_free(struct filedesc *fdp, int low, int size) 117{ 118 NDSLOTTYPE *map = fdp->fd_map; 119 NDSLOTTYPE mask; 120 int off, maxoff; 121 122 if (low >= size) 123 return (low); 124 125 off = NDSLOT(low); 126 if (low % NDENTRIES) { 127 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES))); 128 if ((mask &= ~map[off]) != 0UL) 129 return (off * NDENTRIES + ffsl(mask) - 1); 130 ++off; 131 } 132 for (maxoff = NDSLOTS(size); off < maxoff; ++off) 133 if (map[off] != ~0UL) 134 return (off * NDENTRIES + ffsl(~map[off]) - 1); 135 return (size); 136} 137 138/* 139 * Find the highest non-zero bit in the given bitmap, starting at low and 140 * not exceeding size - 1. 141 */ 142static int 143fd_last_used(struct filedesc *fdp, int low, int size) 144{ 145 NDSLOTTYPE *map = fdp->fd_map; 146 NDSLOTTYPE mask; 147 int off, minoff; 148 149 if (low >= size) 150 return (-1); 151 152 off = NDSLOT(size); 153 if (size % NDENTRIES) { 154 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES)); 155 if ((mask &= map[off]) != 0) 156 return (off * NDENTRIES + flsl(mask) - 1); 157 --off; 158 } 159 for (minoff = NDSLOT(low); off >= minoff; --off) 160 if (map[off] != 0) 161 return (off * NDENTRIES + flsl(map[off]) - 1); 162 return (size - 1); 163} 164 165static int 166fdisused(struct filedesc *fdp, int fd) 167{ 168 KASSERT(fd >= 0 && fd < fdp->fd_nfiles, 169 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles)); 170 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0); 171} 172 173/* 174 * Mark a file descriptor as used. 175 */ 176void 177fdused(struct filedesc *fdp, int fd) 178{ 179 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 180 KASSERT(!fdisused(fdp, fd), 181 ("fd already used")); 182 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd); 183 if (fd > fdp->fd_lastfile) 184 fdp->fd_lastfile = fd; 185 if (fd == fdp->fd_freefile) 186 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 187} 188 189/* 190 * Mark a file descriptor as unused. 191 */ 192void 193fdunused(struct filedesc *fdp, int fd) 194{ 195 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 196 KASSERT(fdisused(fdp, fd), 197 ("fd is already unused")); 198 KASSERT(fdp->fd_ofiles[fd] == NULL, 199 ("fd is still in use")); 200 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd); 201 if (fd < fdp->fd_freefile) 202 fdp->fd_freefile = fd; 203 if (fd == fdp->fd_lastfile) 204 fdp->fd_lastfile = fd_last_used(fdp, 0, fd); 205} 206 207/* 208 * System calls on descriptors. 209 */ 210#ifndef _SYS_SYSPROTO_H_ 211struct getdtablesize_args { 212 int dummy; 213}; 214#endif 215/* 216 * MPSAFE 217 */ 218/* ARGSUSED */ 219int 220getdtablesize(td, uap) 221 struct thread *td; 222 struct getdtablesize_args *uap; 223{ 224 struct proc *p = td->td_proc; 225 226 PROC_LOCK(p); 227 td->td_retval[0] = 228 min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 229 PROC_UNLOCK(p); 230 return (0); 231} 232 233/* 234 * Duplicate a file descriptor to a particular value. 235 * 236 * note: keep in mind that a potential race condition exists when closing 237 * descriptors from a shared descriptor table (via rfork). 238 */ 239#ifndef _SYS_SYSPROTO_H_ 240struct dup2_args { 241 u_int from; 242 u_int to; 243}; 244#endif 245/* 246 * MPSAFE 247 */ 248/* ARGSUSED */ 249int 250dup2(td, uap) 251 struct thread *td; 252 struct dup2_args *uap; 253{ 254 255 return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to, 256 td->td_retval)); 257} 258 259/* 260 * Duplicate a file descriptor. 261 */ 262#ifndef _SYS_SYSPROTO_H_ 263struct dup_args { 264 u_int fd; 265}; 266#endif 267/* 268 * MPSAFE 269 */ 270/* ARGSUSED */ 271int 272dup(td, uap) 273 struct thread *td; 274 struct dup_args *uap; 275{ 276 277 return (do_dup(td, DUP_VARIABLE, (int)uap->fd, 0, td->td_retval)); 278} 279 280/* 281 * The file control system call. 282 */ 283#ifndef _SYS_SYSPROTO_H_ 284struct fcntl_args { 285 int fd; 286 int cmd; 287 long arg; 288}; 289#endif 290/* 291 * MPSAFE 292 */ 293/* ARGSUSED */ 294int 295fcntl(td, uap) 296 struct thread *td; 297 struct fcntl_args *uap; 298{ 299 struct flock fl; 300 intptr_t arg; 301 int error; 302 303 error = 0; 304 switch (uap->cmd) { 305 case F_GETLK: 306 case F_SETLK: 307 case F_SETLKW: 308 error = copyin((void *)(intptr_t)uap->arg, &fl, sizeof(fl)); 309 arg = (intptr_t)&fl; 310 break; 311 default: 312 arg = uap->arg; 313 break; 314 } 315 if (error) 316 return (error); 317 error = kern_fcntl(td, uap->fd, uap->cmd, arg); 318 if (error) 319 return (error); 320 if (uap->cmd == F_GETLK) 321 error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl)); 322 return (error); 323} 324 325int 326kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) 327{ 328 struct filedesc *fdp; 329 struct flock *flp; 330 struct file *fp; 331 struct proc *p; 332 char *pop; 333 struct vnode *vp; 334 u_int newmin; 335 int error, flg, tmp; 336 int giant_locked; 337 338 /* 339 * XXXRW: Some fcntl() calls require Giant -- others don't. Try to 340 * avoid grabbing Giant for calls we know don't need it. 341 */ 342 switch (cmd) { 343 case F_DUPFD: 344 case F_GETFD: 345 case F_SETFD: 346 case F_GETFL: 347 giant_locked = 0; 348 break; 349 350 default: 351 giant_locked = 1; 352 mtx_lock(&Giant); 353 } 354 355 error = 0; 356 flg = F_POSIX; 357 p = td->td_proc; 358 fdp = p->p_fd; 359 FILEDESC_LOCK(fdp); 360 if ((unsigned)fd >= fdp->fd_nfiles || 361 (fp = fdp->fd_ofiles[fd]) == NULL) { 362 FILEDESC_UNLOCK(fdp); 363 error = EBADF; 364 goto done2; 365 } 366 pop = &fdp->fd_ofileflags[fd]; 367 368 switch (cmd) { 369 case F_DUPFD: 370 /* mtx_assert(&Giant, MA_NOTOWNED); */ 371 FILEDESC_UNLOCK(fdp); 372 newmin = arg; 373 PROC_LOCK(p); 374 if (newmin >= lim_cur(p, RLIMIT_NOFILE) || 375 newmin >= maxfilesperproc) { 376 PROC_UNLOCK(p); 377 error = EINVAL; 378 break; 379 } 380 PROC_UNLOCK(p); 381 error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval); 382 break; 383 384 case F_GETFD: 385 /* mtx_assert(&Giant, MA_NOTOWNED); */ 386 td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0; 387 FILEDESC_UNLOCK(fdp); 388 break; 389 390 case F_SETFD: 391 /* mtx_assert(&Giant, MA_NOTOWNED); */ 392 *pop = (*pop &~ UF_EXCLOSE) | 393 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0); 394 FILEDESC_UNLOCK(fdp); 395 break; 396 397 case F_GETFL: 398 /* mtx_assert(&Giant, MA_NOTOWNED); */ 399 FILE_LOCK(fp); 400 FILEDESC_UNLOCK(fdp); 401 td->td_retval[0] = OFLAGS(fp->f_flag); 402 FILE_UNLOCK(fp); 403 break; 404 405 case F_SETFL: 406 mtx_assert(&Giant, MA_OWNED); 407 FILE_LOCK(fp); 408 FILEDESC_UNLOCK(fdp); 409 fhold_locked(fp); 410 fp->f_flag &= ~FCNTLFLAGS; 411 fp->f_flag |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS; 412 FILE_UNLOCK(fp); 413 tmp = fp->f_flag & FNONBLOCK; 414 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 415 if (error) { 416 fdrop(fp, td); 417 break; 418 } 419 tmp = fp->f_flag & FASYNC; 420 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); 421 if (error == 0) { 422 fdrop(fp, td); 423 break; 424 } 425 FILE_LOCK(fp); 426 fp->f_flag &= ~FNONBLOCK; 427 FILE_UNLOCK(fp); 428 tmp = 0; 429 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 430 fdrop(fp, td); 431 break; 432 433 case F_GETOWN: 434 mtx_assert(&Giant, MA_OWNED); 435 fhold(fp); 436 FILEDESC_UNLOCK(fdp); 437 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td); 438 if (error == 0) 439 td->td_retval[0] = tmp; 440 fdrop(fp, td); 441 break; 442 443 case F_SETOWN: 444 mtx_assert(&Giant, MA_OWNED); 445 fhold(fp); 446 FILEDESC_UNLOCK(fdp); 447 tmp = arg; 448 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td); 449 fdrop(fp, td); 450 break; 451 452 case F_SETLKW: 453 mtx_assert(&Giant, MA_OWNED); 454 flg |= F_WAIT; 455 /* FALLTHROUGH F_SETLK */ 456 457 case F_SETLK: 458 mtx_assert(&Giant, MA_OWNED); 459 if (fp->f_type != DTYPE_VNODE) { 460 FILEDESC_UNLOCK(fdp); 461 error = EBADF; 462 break; 463 } 464 465 flp = (struct flock *)arg; 466 if (flp->l_whence == SEEK_CUR) { 467 if (fp->f_offset < 0 || 468 (flp->l_start > 0 && 469 fp->f_offset > OFF_MAX - flp->l_start)) { 470 FILEDESC_UNLOCK(fdp); 471 error = EOVERFLOW; 472 break; 473 } 474 flp->l_start += fp->f_offset; 475 } 476 477 /* 478 * VOP_ADVLOCK() may block. 479 */ 480 fhold(fp); 481 FILEDESC_UNLOCK(fdp); 482 vp = fp->f_vnode; 483 484 switch (flp->l_type) { 485 case F_RDLCK: 486 if ((fp->f_flag & FREAD) == 0) { 487 error = EBADF; 488 break; 489 } 490 PROC_LOCK(p->p_leader); 491 p->p_leader->p_flag |= P_ADVLOCK; 492 PROC_UNLOCK(p->p_leader); 493 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 494 flp, flg); 495 break; 496 case F_WRLCK: 497 if ((fp->f_flag & FWRITE) == 0) { 498 error = EBADF; 499 break; 500 } 501 PROC_LOCK(p->p_leader); 502 p->p_leader->p_flag |= P_ADVLOCK; 503 PROC_UNLOCK(p->p_leader); 504 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 505 flp, flg); 506 break; 507 case F_UNLCK: 508 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 509 flp, F_POSIX); 510 break; 511 default: 512 error = EINVAL; 513 break; 514 } 515 /* Check for race with close */ 516 FILEDESC_LOCK(fdp); 517 if ((unsigned) fd >= fdp->fd_nfiles || 518 fp != fdp->fd_ofiles[fd]) { 519 FILEDESC_UNLOCK(fdp); 520 flp->l_whence = SEEK_SET; 521 flp->l_start = 0; 522 flp->l_len = 0; 523 flp->l_type = F_UNLCK; 524 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 525 F_UNLCK, flp, F_POSIX); 526 } else 527 FILEDESC_UNLOCK(fdp); 528 fdrop(fp, td); 529 break; 530 531 case F_GETLK: 532 mtx_assert(&Giant, MA_OWNED); 533 if (fp->f_type != DTYPE_VNODE) { 534 FILEDESC_UNLOCK(fdp); 535 error = EBADF; 536 break; 537 } 538 flp = (struct flock *)arg; 539 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK && 540 flp->l_type != F_UNLCK) { 541 FILEDESC_UNLOCK(fdp); 542 error = EINVAL; 543 break; 544 } 545 if (flp->l_whence == SEEK_CUR) { 546 if ((flp->l_start > 0 && 547 fp->f_offset > OFF_MAX - flp->l_start) || 548 (flp->l_start < 0 && 549 fp->f_offset < OFF_MIN - flp->l_start)) { 550 FILEDESC_UNLOCK(fdp); 551 error = EOVERFLOW; 552 break; 553 } 554 flp->l_start += fp->f_offset; 555 } 556 /* 557 * VOP_ADVLOCK() may block. 558 */ 559 fhold(fp); 560 FILEDESC_UNLOCK(fdp); 561 vp = fp->f_vnode; 562 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp, 563 F_POSIX); 564 fdrop(fp, td); 565 break; 566 default: 567 FILEDESC_UNLOCK(fdp); 568 error = EINVAL; 569 break; 570 } 571done2: 572 if (giant_locked) 573 mtx_unlock(&Giant); 574 return (error); 575} 576 577/* 578 * Common code for dup, dup2, and fcntl(F_DUPFD). 579 */ 580static int 581do_dup(td, type, old, new, retval) 582 enum dup_type type; 583 int old, new; 584 register_t *retval; 585 struct thread *td; 586{ 587 struct filedesc *fdp; 588 struct proc *p; 589 struct file *fp; 590 struct file *delfp; 591 int error, holdleaders, maxfd; 592 593 KASSERT((type == DUP_VARIABLE || type == DUP_FIXED), 594 ("invalid dup type %d", type)); 595 596 p = td->td_proc; 597 fdp = p->p_fd; 598 599 /* 600 * Verify we have a valid descriptor to dup from and possibly to 601 * dup to. 602 */ 603 if (old < 0 || new < 0) 604 return (EBADF); 605 PROC_LOCK(p); 606 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 607 PROC_UNLOCK(p); 608 if (new >= maxfd) 609 return (EMFILE); 610 611 FILEDESC_LOCK(fdp); 612 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) { 613 FILEDESC_UNLOCK(fdp); 614 return (EBADF); 615 } 616 if (type == DUP_FIXED && old == new) { 617 *retval = new; 618 FILEDESC_UNLOCK(fdp); 619 return (0); 620 } 621 fp = fdp->fd_ofiles[old]; 622 fhold(fp); 623 624 /* 625 * If the caller specified a file descriptor, make sure the file 626 * table is large enough to hold it, and grab it. Otherwise, just 627 * allocate a new descriptor the usual way. Since the filedesc 628 * lock may be temporarily dropped in the process, we have to look 629 * out for a race. 630 */ 631 if (type == DUP_FIXED) { 632 if (new >= fdp->fd_nfiles) 633 fdgrowtable(fdp, new + 1); 634 if (fdp->fd_ofiles[new] == NULL) 635 fdused(fdp, new); 636 } else { 637 if ((error = fdalloc(td, new, &new)) != 0) { 638 FILEDESC_UNLOCK(fdp); 639 fdrop(fp, td); 640 return (error); 641 } 642 } 643 644 /* 645 * If the old file changed out from under us then treat it as a 646 * bad file descriptor. Userland should do its own locking to 647 * avoid this case. 648 */ 649 if (fdp->fd_ofiles[old] != fp) { 650 /* we've allocated a descriptor which we won't use */ 651 if (fdp->fd_ofiles[new] == NULL) 652 fdunused(fdp, new); 653 FILEDESC_UNLOCK(fdp); 654 fdrop(fp, td); 655 return (EBADF); 656 } 657 KASSERT(old != new, 658 ("new fd is same as old")); 659 660 /* 661 * Save info on the descriptor being overwritten. We cannot close 662 * it without introducing an ownership race for the slot, since we 663 * need to drop the filedesc lock to call closef(). 664 * 665 * XXX this duplicates parts of close(). 666 */ 667 delfp = fdp->fd_ofiles[new]; 668 holdleaders = 0; 669 if (delfp != NULL) { 670 if (td->td_proc->p_fdtol != NULL) { 671 /* 672 * Ask fdfree() to sleep to ensure that all relevant 673 * process leaders can be traversed in closef(). 674 */ 675 fdp->fd_holdleaderscount++; 676 holdleaders = 1; 677 } 678 } 679 680 /* 681 * Duplicate the source descriptor 682 */ 683 fdp->fd_ofiles[new] = fp; 684 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE; 685 if (new > fdp->fd_lastfile) 686 fdp->fd_lastfile = new; 687 *retval = new; 688 689 /* 690 * If we dup'd over a valid file, we now own the reference to it 691 * and must dispose of it using closef() semantics (as if a 692 * close() were performed on it). 693 * 694 * XXX this duplicates parts of close(). 695 */ 696 if (delfp != NULL) { 697 knote_fdclose(td, new); 698 FILEDESC_UNLOCK(fdp); 699 mtx_lock(&Giant); 700 (void) closef(delfp, td); 701 mtx_unlock(&Giant); 702 if (holdleaders) { 703 FILEDESC_LOCK(fdp); 704 fdp->fd_holdleaderscount--; 705 if (fdp->fd_holdleaderscount == 0 && 706 fdp->fd_holdleaderswakeup != 0) { 707 fdp->fd_holdleaderswakeup = 0; 708 wakeup(&fdp->fd_holdleaderscount); 709 } 710 FILEDESC_UNLOCK(fdp); 711 } 712 } else { 713 FILEDESC_UNLOCK(fdp); 714 } 715 return (0); 716} 717 718/* 719 * If sigio is on the list associated with a process or process group, 720 * disable signalling from the device, remove sigio from the list and 721 * free sigio. 722 */ 723void 724funsetown(sigiop) 725 struct sigio **sigiop; 726{ 727 struct sigio *sigio; 728 729 SIGIO_LOCK(); 730 sigio = *sigiop; 731 if (sigio == NULL) { 732 SIGIO_UNLOCK(); 733 return; 734 } 735 *(sigio->sio_myref) = NULL; 736 if ((sigio)->sio_pgid < 0) { 737 struct pgrp *pg = (sigio)->sio_pgrp; 738 PGRP_LOCK(pg); 739 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 740 sigio, sio_pgsigio); 741 PGRP_UNLOCK(pg); 742 } else { 743 struct proc *p = (sigio)->sio_proc; 744 PROC_LOCK(p); 745 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 746 sigio, sio_pgsigio); 747 PROC_UNLOCK(p); 748 } 749 SIGIO_UNLOCK(); 750 crfree(sigio->sio_ucred); 751 FREE(sigio, M_SIGIO); 752} 753 754/* 755 * Free a list of sigio structures. 756 * We only need to lock the SIGIO_LOCK because we have made ourselves 757 * inaccessable to callers of fsetown and therefore do not need to lock 758 * the proc or pgrp struct for the list manipulation. 759 */ 760void 761funsetownlst(sigiolst) 762 struct sigiolst *sigiolst; 763{ 764 struct proc *p; 765 struct pgrp *pg; 766 struct sigio *sigio; 767 768 sigio = SLIST_FIRST(sigiolst); 769 if (sigio == NULL) 770 return; 771 p = NULL; 772 pg = NULL; 773 774 /* 775 * Every entry of the list should belong 776 * to a single proc or pgrp. 777 */ 778 if (sigio->sio_pgid < 0) { 779 pg = sigio->sio_pgrp; 780 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED); 781 } else /* if (sigio->sio_pgid > 0) */ { 782 p = sigio->sio_proc; 783 PROC_LOCK_ASSERT(p, MA_NOTOWNED); 784 } 785 786 SIGIO_LOCK(); 787 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) { 788 *(sigio->sio_myref) = NULL; 789 if (pg != NULL) { 790 KASSERT(sigio->sio_pgid < 0, 791 ("Proc sigio in pgrp sigio list")); 792 KASSERT(sigio->sio_pgrp == pg, 793 ("Bogus pgrp in sigio list")); 794 PGRP_LOCK(pg); 795 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio, 796 sio_pgsigio); 797 PGRP_UNLOCK(pg); 798 } else /* if (p != NULL) */ { 799 KASSERT(sigio->sio_pgid > 0, 800 ("Pgrp sigio in proc sigio list")); 801 KASSERT(sigio->sio_proc == p, 802 ("Bogus proc in sigio list")); 803 PROC_LOCK(p); 804 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, 805 sio_pgsigio); 806 PROC_UNLOCK(p); 807 } 808 SIGIO_UNLOCK(); 809 crfree(sigio->sio_ucred); 810 FREE(sigio, M_SIGIO); 811 SIGIO_LOCK(); 812 } 813 SIGIO_UNLOCK(); 814} 815 816/* 817 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 818 * 819 * After permission checking, add a sigio structure to the sigio list for 820 * the process or process group. 821 */ 822int 823fsetown(pgid, sigiop) 824 pid_t pgid; 825 struct sigio **sigiop; 826{ 827 struct proc *proc; 828 struct pgrp *pgrp; 829 struct sigio *sigio; 830 int ret; 831 832 if (pgid == 0) { 833 funsetown(sigiop); 834 return (0); 835 } 836 837 ret = 0; 838 839 /* Allocate and fill in the new sigio out of locks. */ 840 MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK); 841 sigio->sio_pgid = pgid; 842 sigio->sio_ucred = crhold(curthread->td_ucred); 843 sigio->sio_myref = sigiop; 844 845 sx_slock(&proctree_lock); 846 if (pgid > 0) { 847 proc = pfind(pgid); 848 if (proc == NULL) { 849 ret = ESRCH; 850 goto fail; 851 } 852 853 /* 854 * Policy - Don't allow a process to FSETOWN a process 855 * in another session. 856 * 857 * Remove this test to allow maximum flexibility or 858 * restrict FSETOWN to the current process or process 859 * group for maximum safety. 860 */ 861 PROC_UNLOCK(proc); 862 if (proc->p_session != curthread->td_proc->p_session) { 863 ret = EPERM; 864 goto fail; 865 } 866 867 pgrp = NULL; 868 } else /* if (pgid < 0) */ { 869 pgrp = pgfind(-pgid); 870 if (pgrp == NULL) { 871 ret = ESRCH; 872 goto fail; 873 } 874 PGRP_UNLOCK(pgrp); 875 876 /* 877 * Policy - Don't allow a process to FSETOWN a process 878 * in another session. 879 * 880 * Remove this test to allow maximum flexibility or 881 * restrict FSETOWN to the current process or process 882 * group for maximum safety. 883 */ 884 if (pgrp->pg_session != curthread->td_proc->p_session) { 885 ret = EPERM; 886 goto fail; 887 } 888 889 proc = NULL; 890 } 891 funsetown(sigiop); 892 if (pgid > 0) { 893 PROC_LOCK(proc); 894 /* 895 * Since funsetownlst() is called without the proctree 896 * locked, we need to check for P_WEXIT. 897 * XXX: is ESRCH correct? 898 */ 899 if ((proc->p_flag & P_WEXIT) != 0) { 900 PROC_UNLOCK(proc); 901 ret = ESRCH; 902 goto fail; 903 } 904 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 905 sigio->sio_proc = proc; 906 PROC_UNLOCK(proc); 907 } else { 908 PGRP_LOCK(pgrp); 909 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 910 sigio->sio_pgrp = pgrp; 911 PGRP_UNLOCK(pgrp); 912 } 913 sx_sunlock(&proctree_lock); 914 SIGIO_LOCK(); 915 *sigiop = sigio; 916 SIGIO_UNLOCK(); 917 return (0); 918 919fail: 920 sx_sunlock(&proctree_lock); 921 crfree(sigio->sio_ucred); 922 FREE(sigio, M_SIGIO); 923 return (ret); 924} 925 926/* 927 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 928 */ 929pid_t 930fgetown(sigiop) 931 struct sigio **sigiop; 932{ 933 pid_t pgid; 934 935 SIGIO_LOCK(); 936 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0; 937 SIGIO_UNLOCK(); 938 return (pgid); 939} 940 941/* 942 * Close a file descriptor. 943 */ 944#ifndef _SYS_SYSPROTO_H_ 945struct close_args { 946 int fd; 947}; 948#endif 949/* 950 * MPSAFE 951 */ 952/* ARGSUSED */ 953int 954close(td, uap) 955 struct thread *td; 956 struct close_args *uap; 957{ 958 struct filedesc *fdp; 959 struct file *fp; 960 int fd, error; 961 int holdleaders; 962 963 fd = uap->fd; 964 error = 0; 965 holdleaders = 0; 966 fdp = td->td_proc->p_fd; 967 mtx_lock(&Giant); 968 FILEDESC_LOCK(fdp); 969 if ((unsigned)fd >= fdp->fd_nfiles || 970 (fp = fdp->fd_ofiles[fd]) == NULL) { 971 FILEDESC_UNLOCK(fdp); 972 mtx_unlock(&Giant); 973 return (EBADF); 974 } 975 fdp->fd_ofiles[fd] = NULL; 976 fdp->fd_ofileflags[fd] = 0; 977 fdunused(fdp, fd); 978 if (td->td_proc->p_fdtol != NULL) { 979 /* 980 * Ask fdfree() to sleep to ensure that all relevant 981 * process leaders can be traversed in closef(). 982 */ 983 fdp->fd_holdleaderscount++; 984 holdleaders = 1; 985 } 986 987 /* 988 * we now hold the fp reference that used to be owned by the descriptor 989 * array. 990 * We have to unlock the FILEDESC *AFTER* knote_fdclose to prevent a 991 * race of the fd getting opened, a knote added, and deleteing a knote 992 * for the new fd. 993 */ 994 knote_fdclose(td, fd); 995 FILEDESC_UNLOCK(fdp); 996 997 error = closef(fp, td); 998 mtx_unlock(&Giant); 999 if (holdleaders) { 1000 FILEDESC_LOCK(fdp); 1001 fdp->fd_holdleaderscount--; 1002 if (fdp->fd_holdleaderscount == 0 && 1003 fdp->fd_holdleaderswakeup != 0) { 1004 fdp->fd_holdleaderswakeup = 0; 1005 wakeup(&fdp->fd_holdleaderscount); 1006 } 1007 FILEDESC_UNLOCK(fdp); 1008 } 1009 return (error); 1010} 1011 1012#if defined(COMPAT_43) 1013/* 1014 * Return status information about a file descriptor. 1015 */ 1016#ifndef _SYS_SYSPROTO_H_ 1017struct ofstat_args { 1018 int fd; 1019 struct ostat *sb; 1020}; 1021#endif 1022/* 1023 * MPSAFE 1024 */ 1025/* ARGSUSED */ 1026int 1027ofstat(td, uap) 1028 struct thread *td; 1029 struct ofstat_args *uap; 1030{ 1031 struct file *fp; 1032 struct stat ub; 1033 struct ostat oub; 1034 int error; 1035 1036 if ((error = fget(td, uap->fd, &fp)) != 0) 1037 goto done2; 1038 error = fo_stat(fp, &ub, td->td_ucred, td); 1039 if (error == 0) { 1040 cvtstat(&ub, &oub); 1041 error = copyout(&oub, uap->sb, sizeof(oub)); 1042 } 1043 fdrop(fp, td); 1044done2: 1045 return (error); 1046} 1047#endif /* COMPAT_43 */ 1048 1049/* 1050 * Return status information about a file descriptor. 1051 */ 1052#ifndef _SYS_SYSPROTO_H_ 1053struct fstat_args { 1054 int fd; 1055 struct stat *sb; 1056}; 1057#endif 1058/* 1059 * MPSAFE 1060 */ 1061/* ARGSUSED */ 1062int 1063fstat(td, uap) 1064 struct thread *td; 1065 struct fstat_args *uap; 1066{ 1067 struct file *fp; 1068 struct stat ub; 1069 int error; 1070 1071 if ((error = fget(td, uap->fd, &fp)) != 0) 1072 goto done2; 1073 error = fo_stat(fp, &ub, td->td_ucred, td); 1074 if (error == 0) 1075 error = copyout(&ub, uap->sb, sizeof(ub)); 1076 fdrop(fp, td); 1077done2: 1078 return (error); 1079} 1080 1081/* 1082 * Return status information about a file descriptor. 1083 */ 1084#ifndef _SYS_SYSPROTO_H_ 1085struct nfstat_args { 1086 int fd; 1087 struct nstat *sb; 1088}; 1089#endif 1090/* 1091 * MPSAFE 1092 */ 1093/* ARGSUSED */ 1094int 1095nfstat(td, uap) 1096 struct thread *td; 1097 struct nfstat_args *uap; 1098{ 1099 struct file *fp; 1100 struct stat ub; 1101 struct nstat nub; 1102 int error; 1103 1104 if ((error = fget(td, uap->fd, &fp)) != 0) 1105 goto done2; 1106 error = fo_stat(fp, &ub, td->td_ucred, td); 1107 if (error == 0) { 1108 cvtnstat(&ub, &nub); 1109 error = copyout(&nub, uap->sb, sizeof(nub)); 1110 } 1111 fdrop(fp, td); 1112done2: 1113 return (error); 1114} 1115 1116/* 1117 * Return pathconf information about a file descriptor. 1118 */ 1119#ifndef _SYS_SYSPROTO_H_ 1120struct fpathconf_args { 1121 int fd; 1122 int name; 1123}; 1124#endif 1125/* 1126 * MPSAFE 1127 */ 1128/* ARGSUSED */ 1129int 1130fpathconf(td, uap) 1131 struct thread *td; 1132 struct fpathconf_args *uap; 1133{ 1134 struct file *fp; 1135 struct vnode *vp; 1136 int error; 1137 1138 if ((error = fget(td, uap->fd, &fp)) != 0) 1139 return (error); 1140 1141 /* If asynchronous I/O is available, it works for all descriptors. */ 1142 if (uap->name == _PC_ASYNC_IO) { 1143 td->td_retval[0] = async_io_version; 1144 goto out; 1145 } 1146 vp = fp->f_vnode; 1147 if (vp != NULL) { 1148 mtx_lock(&Giant); 1149 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 1150 error = VOP_PATHCONF(vp, uap->name, td->td_retval); 1151 VOP_UNLOCK(vp, 0, td); 1152 mtx_unlock(&Giant); 1153 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) { 1154 if (uap->name != _PC_PIPE_BUF) { 1155 error = EINVAL; 1156 } else { 1157 td->td_retval[0] = PIPE_BUF; 1158 error = 0; 1159 } 1160 } else { 1161 error = EOPNOTSUPP; 1162 } 1163out: 1164 fdrop(fp, td); 1165 return (error); 1166} 1167 1168/* 1169 * Grow the file table to accomodate (at least) nfd descriptors. This may 1170 * block and drop the filedesc lock, but it will reacquire it before 1171 * returing. 1172 */ 1173static void 1174fdgrowtable(struct filedesc *fdp, int nfd) 1175{ 1176 struct file **ntable; 1177 char *nfileflags; 1178 int nnfiles, onfiles; 1179 NDSLOTTYPE *nmap; 1180 1181 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1182 1183 KASSERT(fdp->fd_nfiles > 0, 1184 ("zero-length file table")); 1185 1186 /* compute the size of the new table */ 1187 onfiles = fdp->fd_nfiles; 1188 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */ 1189 if (nnfiles <= onfiles) 1190 /* the table is already large enough */ 1191 return; 1192 1193 /* allocate a new table and (if required) new bitmaps */ 1194 FILEDESC_UNLOCK(fdp); 1195 MALLOC(ntable, struct file **, nnfiles * OFILESIZE, 1196 M_FILEDESC, M_ZERO | M_WAITOK); 1197 nfileflags = (char *)&ntable[nnfiles]; 1198 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) 1199 MALLOC(nmap, NDSLOTTYPE *, NDSLOTS(nnfiles) * NDSLOTSIZE, 1200 M_FILEDESC, M_ZERO | M_WAITOK); 1201 else 1202 nmap = NULL; 1203 FILEDESC_LOCK(fdp); 1204 1205 /* 1206 * We now have new tables ready to go. Since we dropped the 1207 * filedesc lock to call malloc(), watch out for a race. 1208 */ 1209 onfiles = fdp->fd_nfiles; 1210 if (onfiles >= nnfiles) { 1211 /* we lost the race, but that's OK */ 1212 free(ntable, M_FILEDESC); 1213 if (nmap != NULL) 1214 free(nmap, M_FILEDESC); 1215 return; 1216 } 1217 bcopy(fdp->fd_ofiles, ntable, onfiles * sizeof(*ntable)); 1218 bcopy(fdp->fd_ofileflags, nfileflags, onfiles); 1219 if (onfiles > NDFILE) 1220 free(fdp->fd_ofiles, M_FILEDESC); 1221 fdp->fd_ofiles = ntable; 1222 fdp->fd_ofileflags = nfileflags; 1223 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) { 1224 bcopy(fdp->fd_map, nmap, NDSLOTS(onfiles) * sizeof(*nmap)); 1225 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE)) 1226 free(fdp->fd_map, M_FILEDESC); 1227 fdp->fd_map = nmap; 1228 } 1229 fdp->fd_nfiles = nnfiles; 1230} 1231 1232/* 1233 * Allocate a file descriptor for the process. 1234 */ 1235int 1236fdalloc(struct thread *td, int minfd, int *result) 1237{ 1238 struct proc *p = td->td_proc; 1239 struct filedesc *fdp = p->p_fd; 1240 int fd = -1, maxfd; 1241 1242 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1243 1244 PROC_LOCK(p); 1245 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1246 PROC_UNLOCK(p); 1247 1248 /* 1249 * Search the bitmap for a free descriptor. If none is found, try 1250 * to grow the file table. Keep at it until we either get a file 1251 * descriptor or run into process or system limits; fdgrowtable() 1252 * may drop the filedesc lock, so we're in a race. 1253 */ 1254 for (;;) { 1255 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); 1256 if (fd >= maxfd) 1257 return (EMFILE); 1258 if (fd < fdp->fd_nfiles) 1259 break; 1260 fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd)); 1261 } 1262 1263 /* 1264 * Perform some sanity checks, then mark the file descriptor as 1265 * used and return it to the caller. 1266 */ 1267 KASSERT(!fdisused(fdp, fd), 1268 ("fd_first_free() returned non-free descriptor")); 1269 KASSERT(fdp->fd_ofiles[fd] == NULL, 1270 ("free descriptor isn't")); 1271 fdp->fd_ofileflags[fd] = 0; /* XXX needed? */ 1272 fdused(fdp, fd); 1273 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 1274 *result = fd; 1275 return (0); 1276} 1277 1278/* 1279 * Check to see whether n user file descriptors 1280 * are available to the process p. 1281 */ 1282int 1283fdavail(td, n) 1284 struct thread *td; 1285 int n; 1286{ 1287 struct proc *p = td->td_proc; 1288 struct filedesc *fdp = td->td_proc->p_fd; 1289 struct file **fpp; 1290 int i, lim, last; 1291 1292 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1293 1294 PROC_LOCK(p); 1295 lim = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1296 PROC_UNLOCK(p); 1297 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) 1298 return (1); 1299 last = min(fdp->fd_nfiles, lim); 1300 fpp = &fdp->fd_ofiles[fdp->fd_freefile]; 1301 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) { 1302 if (*fpp == NULL && --n <= 0) 1303 return (1); 1304 } 1305 return (0); 1306} 1307 1308/* 1309 * Create a new open file structure and allocate 1310 * a file decriptor for the process that refers to it. 1311 * We add one reference to the file for the descriptor table 1312 * and one reference for resultfp. This is to prevent us being 1313 * prempted and the entry in the descriptor table closed after 1314 * we release the FILEDESC lock. 1315 */ 1316int 1317falloc(td, resultfp, resultfd) 1318 struct thread *td; 1319 struct file **resultfp; 1320 int *resultfd; 1321{ 1322 struct proc *p = td->td_proc; 1323 struct file *fp, *fq; 1324 int error, i; 1325 int maxuserfiles = maxfiles - (maxfiles / 20); 1326 static struct timeval lastfail; 1327 static int curfail; 1328 1329 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO); 1330 sx_xlock(&filelist_lock); 1331 if ((nfiles >= maxuserfiles && (td->td_ucred->cr_ruid != 0 || 1332 jailed(td->td_ucred))) || nfiles >= maxfiles) { 1333 if (ppsratecheck(&lastfail, &curfail, 1)) { 1334 printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n", 1335 td->td_ucred->cr_ruid); 1336 } 1337 sx_xunlock(&filelist_lock); 1338 uma_zfree(file_zone, fp); 1339 return (ENFILE); 1340 } 1341 nfiles++; 1342 1343 /* 1344 * If the process has file descriptor zero open, add the new file 1345 * descriptor to the list of open files at that point, otherwise 1346 * put it at the front of the list of open files. 1347 */ 1348 fp->f_mtxp = mtx_pool_alloc(mtxpool_sleep); 1349 fp->f_count = 1; 1350 if (resultfp) 1351 fp->f_count++; 1352 fp->f_cred = crhold(td->td_ucred); 1353 fp->f_ops = &badfileops; 1354 fp->f_data = NULL; 1355 fp->f_vnode = NULL; 1356 FILEDESC_LOCK(p->p_fd); 1357 if ((fq = p->p_fd->fd_ofiles[0])) { 1358 LIST_INSERT_AFTER(fq, fp, f_list); 1359 } else { 1360 LIST_INSERT_HEAD(&filehead, fp, f_list); 1361 } 1362 sx_xunlock(&filelist_lock); 1363 if ((error = fdalloc(td, 0, &i))) { 1364 FILEDESC_UNLOCK(p->p_fd); 1365 fdrop(fp, td); 1366 if (resultfp) 1367 fdrop(fp, td); 1368 return (error); 1369 } 1370 p->p_fd->fd_ofiles[i] = fp; 1371 FILEDESC_UNLOCK(p->p_fd); 1372 if (resultfp) 1373 *resultfp = fp; 1374 if (resultfd) 1375 *resultfd = i; 1376 return (0); 1377} 1378 1379/* 1380 * Free a file descriptor. 1381 */ 1382void 1383ffree(fp) 1384 struct file *fp; 1385{ 1386 1387 KASSERT(fp->f_count == 0, ("ffree: fp_fcount not 0!")); 1388 sx_xlock(&filelist_lock); 1389 LIST_REMOVE(fp, f_list); 1390 nfiles--; 1391 sx_xunlock(&filelist_lock); 1392 crfree(fp->f_cred); 1393 uma_zfree(file_zone, fp); 1394} 1395 1396/* 1397 * Build a new filedesc structure from another. 1398 * Copy the current, root, and jail root vnode references. 1399 */ 1400struct filedesc * 1401fdinit(fdp) 1402 struct filedesc *fdp; 1403{ 1404 struct filedesc0 *newfdp; 1405 1406 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1407 1408 FILEDESC_UNLOCK(fdp); 1409 MALLOC(newfdp, struct filedesc0 *, sizeof(struct filedesc0), 1410 M_FILEDESC, M_WAITOK | M_ZERO); 1411 FILEDESC_LOCK(fdp); 1412 mtx_init(&newfdp->fd_fd.fd_mtx, FILEDESC_LOCK_DESC, NULL, MTX_DEF); 1413 newfdp->fd_fd.fd_cdir = fdp->fd_cdir; 1414 if (newfdp->fd_fd.fd_cdir) 1415 VREF(newfdp->fd_fd.fd_cdir); 1416 newfdp->fd_fd.fd_rdir = fdp->fd_rdir; 1417 if (newfdp->fd_fd.fd_rdir) 1418 VREF(newfdp->fd_fd.fd_rdir); 1419 newfdp->fd_fd.fd_jdir = fdp->fd_jdir; 1420 if (newfdp->fd_fd.fd_jdir) 1421 VREF(newfdp->fd_fd.fd_jdir); 1422 1423 /* Create the file descriptor table. */ 1424 newfdp->fd_fd.fd_refcnt = 1; 1425 newfdp->fd_fd.fd_cmask = CMASK; 1426 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; 1427 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; 1428 newfdp->fd_fd.fd_nfiles = NDFILE; 1429 newfdp->fd_fd.fd_map = newfdp->fd_dmap; 1430 return (&newfdp->fd_fd); 1431} 1432 1433/* 1434 * Share a filedesc structure. 1435 */ 1436struct filedesc * 1437fdshare(fdp) 1438 struct filedesc *fdp; 1439{ 1440 FILEDESC_LOCK(fdp); 1441 fdp->fd_refcnt++; 1442 FILEDESC_UNLOCK(fdp); 1443 return (fdp); 1444} 1445 1446/* 1447 * Copy a filedesc structure. 1448 * A NULL pointer in returns a NULL reference, this is to ease callers, 1449 * not catch errors. 1450 */ 1451struct filedesc * 1452fdcopy(fdp) 1453 struct filedesc *fdp; 1454{ 1455 struct filedesc *newfdp; 1456 int i; 1457 1458 /* Certain daemons might not have file descriptors. */ 1459 if (fdp == NULL) 1460 return (NULL); 1461 1462 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1463 newfdp = fdinit(fdp); 1464 while (fdp->fd_lastfile >= newfdp->fd_nfiles) { 1465 FILEDESC_UNLOCK(fdp); 1466 FILEDESC_LOCK(newfdp); 1467 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1468 FILEDESC_UNLOCK(newfdp); 1469 FILEDESC_LOCK(fdp); 1470 } 1471 /* copy everything except kqueue descriptors */ 1472 newfdp->fd_freefile = -1; 1473 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1474 if (fdisused(fdp, i) && 1475 fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE) { 1476 newfdp->fd_ofiles[i] = fdp->fd_ofiles[i]; 1477 newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i]; 1478 fhold(newfdp->fd_ofiles[i]); 1479 newfdp->fd_lastfile = i; 1480 } else { 1481 if (newfdp->fd_freefile == -1) 1482 newfdp->fd_freefile = i; 1483 } 1484 } 1485 FILEDESC_UNLOCK(fdp); 1486 FILEDESC_LOCK(newfdp); 1487 for (i = 0; i <= newfdp->fd_lastfile; ++i) 1488 if (newfdp->fd_ofiles[i] != NULL) 1489 fdused(newfdp, i); 1490 FILEDESC_UNLOCK(newfdp); 1491 FILEDESC_LOCK(fdp); 1492 if (newfdp->fd_freefile == -1) 1493 newfdp->fd_freefile = i; 1494 newfdp->fd_cmask = fdp->fd_cmask; 1495 return (newfdp); 1496} 1497 1498/* A mutex to protect the association between a proc and filedesc. */ 1499struct mtx fdesc_mtx; 1500MTX_SYSINIT(fdesc, &fdesc_mtx, "fdesc", MTX_DEF); 1501 1502/* 1503 * Release a filedesc structure. 1504 */ 1505void 1506fdfree(td) 1507 struct thread *td; 1508{ 1509 struct filedesc *fdp; 1510 struct file **fpp; 1511 int i; 1512 struct filedesc_to_leader *fdtol; 1513 struct file *fp; 1514 struct vnode *vp; 1515 struct flock lf; 1516 1517 GIANT_REQUIRED; /* VFS */ 1518 1519 /* Certain daemons might not have file descriptors. */ 1520 fdp = td->td_proc->p_fd; 1521 if (fdp == NULL) 1522 return; 1523 1524 /* Check for special need to clear POSIX style locks */ 1525 fdtol = td->td_proc->p_fdtol; 1526 if (fdtol != NULL) { 1527 FILEDESC_LOCK(fdp); 1528 KASSERT(fdtol->fdl_refcount > 0, 1529 ("filedesc_to_refcount botch: fdl_refcount=%d", 1530 fdtol->fdl_refcount)); 1531 if (fdtol->fdl_refcount == 1 && 1532 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1533 i = 0; 1534 fpp = fdp->fd_ofiles; 1535 for (i = 0, fpp = fdp->fd_ofiles; 1536 i <= fdp->fd_lastfile; 1537 i++, fpp++) { 1538 if (*fpp == NULL || 1539 (*fpp)->f_type != DTYPE_VNODE) 1540 continue; 1541 fp = *fpp; 1542 fhold(fp); 1543 FILEDESC_UNLOCK(fdp); 1544 lf.l_whence = SEEK_SET; 1545 lf.l_start = 0; 1546 lf.l_len = 0; 1547 lf.l_type = F_UNLCK; 1548 vp = fp->f_vnode; 1549 (void) VOP_ADVLOCK(vp, 1550 (caddr_t)td->td_proc-> 1551 p_leader, 1552 F_UNLCK, 1553 &lf, 1554 F_POSIX); 1555 FILEDESC_LOCK(fdp); 1556 fdrop(fp, td); 1557 fpp = fdp->fd_ofiles + i; 1558 } 1559 } 1560 retry: 1561 if (fdtol->fdl_refcount == 1) { 1562 if (fdp->fd_holdleaderscount > 0 && 1563 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1564 /* 1565 * close() or do_dup() has cleared a reference 1566 * in a shared file descriptor table. 1567 */ 1568 fdp->fd_holdleaderswakeup = 1; 1569 msleep(&fdp->fd_holdleaderscount, &fdp->fd_mtx, 1570 PLOCK, "fdlhold", 0); 1571 goto retry; 1572 } 1573 if (fdtol->fdl_holdcount > 0) { 1574 /* 1575 * Ensure that fdtol->fdl_leader 1576 * remains valid in closef(). 1577 */ 1578 fdtol->fdl_wakeup = 1; 1579 msleep(fdtol, &fdp->fd_mtx, 1580 PLOCK, "fdlhold", 0); 1581 goto retry; 1582 } 1583 } 1584 fdtol->fdl_refcount--; 1585 if (fdtol->fdl_refcount == 0 && 1586 fdtol->fdl_holdcount == 0) { 1587 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1588 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1589 } else 1590 fdtol = NULL; 1591 td->td_proc->p_fdtol = NULL; 1592 FILEDESC_UNLOCK(fdp); 1593 if (fdtol != NULL) 1594 FREE(fdtol, M_FILEDESC_TO_LEADER); 1595 } 1596 FILEDESC_LOCK(fdp); 1597 if (--fdp->fd_refcnt > 0) { 1598 FILEDESC_UNLOCK(fdp); 1599 return; 1600 } 1601 1602 /* 1603 * We are the last reference to the structure, so we can 1604 * safely assume it will not change out from under us. 1605 */ 1606 FILEDESC_UNLOCK(fdp); 1607 fpp = fdp->fd_ofiles; 1608 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) { 1609 if (*fpp) 1610 (void) closef(*fpp, td); 1611 } 1612 1613 /* XXX This should happen earlier. */ 1614 mtx_lock(&fdesc_mtx); 1615 td->td_proc->p_fd = NULL; 1616 mtx_unlock(&fdesc_mtx); 1617 1618 if (fdp->fd_nfiles > NDFILE) 1619 FREE(fdp->fd_ofiles, M_FILEDESC); 1620 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE)) 1621 FREE(fdp->fd_map, M_FILEDESC); 1622 if (fdp->fd_cdir) 1623 vrele(fdp->fd_cdir); 1624 if (fdp->fd_rdir) 1625 vrele(fdp->fd_rdir); 1626 if (fdp->fd_jdir) 1627 vrele(fdp->fd_jdir); 1628 mtx_destroy(&fdp->fd_mtx); 1629 FREE(fdp, M_FILEDESC); 1630} 1631 1632/* 1633 * For setugid programs, we don't want to people to use that setugidness 1634 * to generate error messages which write to a file which otherwise would 1635 * otherwise be off-limits to the process. We check for filesystems where 1636 * the vnode can change out from under us after execve (like [lin]procfs). 1637 * 1638 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 1639 * sufficient. We also don't for check setugidness since we know we are. 1640 */ 1641static int 1642is_unsafe(struct file *fp) 1643{ 1644 if (fp->f_type == DTYPE_VNODE) { 1645 struct vnode *vp = fp->f_vnode; 1646 1647 if ((vp->v_vflag & VV_PROCDEP) != 0) 1648 return (1); 1649 } 1650 return (0); 1651} 1652 1653/* 1654 * Make this setguid thing safe, if at all possible. 1655 */ 1656void 1657setugidsafety(td) 1658 struct thread *td; 1659{ 1660 struct filedesc *fdp; 1661 int i; 1662 1663 /* Certain daemons might not have file descriptors. */ 1664 fdp = td->td_proc->p_fd; 1665 if (fdp == NULL) 1666 return; 1667 1668 /* 1669 * Note: fdp->fd_ofiles may be reallocated out from under us while 1670 * we are blocked in a close. Be careful! 1671 */ 1672 FILEDESC_LOCK(fdp); 1673 for (i = 0; i <= fdp->fd_lastfile; i++) { 1674 if (i > 2) 1675 break; 1676 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) { 1677 struct file *fp; 1678 1679 knote_fdclose(td, i); 1680 /* 1681 * NULL-out descriptor prior to close to avoid 1682 * a race while close blocks. 1683 */ 1684 fp = fdp->fd_ofiles[i]; 1685 fdp->fd_ofiles[i] = NULL; 1686 fdp->fd_ofileflags[i] = 0; 1687 fdunused(fdp, i); 1688 FILEDESC_UNLOCK(fdp); 1689 (void) closef(fp, td); 1690 FILEDESC_LOCK(fdp); 1691 } 1692 } 1693 FILEDESC_UNLOCK(fdp); 1694} 1695 1696/* 1697 * Close any files on exec? 1698 */ 1699void 1700fdcloseexec(td) 1701 struct thread *td; 1702{ 1703 struct filedesc *fdp; 1704 int i; 1705 1706 /* Certain daemons might not have file descriptors. */ 1707 fdp = td->td_proc->p_fd; 1708 if (fdp == NULL) 1709 return; 1710 1711 FILEDESC_LOCK(fdp); 1712 1713 /* 1714 * We cannot cache fd_ofiles or fd_ofileflags since operations 1715 * may block and rip them out from under us. 1716 */ 1717 for (i = 0; i <= fdp->fd_lastfile; i++) { 1718 if (fdp->fd_ofiles[i] != NULL && 1719 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) { 1720 struct file *fp; 1721 1722 knote_fdclose(td, i); 1723 /* 1724 * NULL-out descriptor prior to close to avoid 1725 * a race while close blocks. 1726 */ 1727 fp = fdp->fd_ofiles[i]; 1728 fdp->fd_ofiles[i] = NULL; 1729 fdp->fd_ofileflags[i] = 0; 1730 fdunused(fdp, i); 1731 FILEDESC_UNLOCK(fdp); 1732 (void) closef(fp, td); 1733 FILEDESC_LOCK(fdp); 1734 } 1735 } 1736 FILEDESC_UNLOCK(fdp); 1737} 1738 1739/* 1740 * It is unsafe for set[ug]id processes to be started with file 1741 * descriptors 0..2 closed, as these descriptors are given implicit 1742 * significance in the Standard C library. fdcheckstd() will create a 1743 * descriptor referencing /dev/null for each of stdin, stdout, and 1744 * stderr that is not already open. 1745 */ 1746int 1747fdcheckstd(td) 1748 struct thread *td; 1749{ 1750 struct nameidata nd; 1751 struct filedesc *fdp; 1752 struct file *fp; 1753 register_t retval; 1754 int fd, i, error, flags, devnull; 1755 1756 GIANT_REQUIRED; /* VFS */ 1757 1758 fdp = td->td_proc->p_fd; 1759 if (fdp == NULL) 1760 return (0); 1761 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 1762 devnull = -1; 1763 error = 0; 1764 for (i = 0; i < 3; i++) { 1765 if (fdp->fd_ofiles[i] != NULL) 1766 continue; 1767 if (devnull < 0) { 1768 error = falloc(td, &fp, &fd); 1769 if (error != 0) 1770 break; 1771 /* Note extra ref on `fp' held for us by falloc(). */ 1772 KASSERT(fd == i, ("oof, we didn't get our fd")); 1773 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/null", 1774 td); 1775 flags = FREAD | FWRITE; 1776 error = vn_open(&nd, &flags, 0, -1); 1777 if (error != 0) { 1778 /* 1779 * Someone may have closed the entry in the 1780 * file descriptor table, so check it hasn't 1781 * changed before dropping the reference count. 1782 */ 1783 FILEDESC_LOCK(fdp); 1784 KASSERT(fdp->fd_ofiles[fd] == fp, 1785 ("table not shared, how did it change?")); 1786 fdp->fd_ofiles[fd] = NULL; 1787 fdunused(fdp, fd); 1788 FILEDESC_UNLOCK(fdp); 1789 fdrop(fp, td); 1790 fdrop(fp, td); 1791 break; 1792 } 1793 NDFREE(&nd, NDF_ONLY_PNBUF); 1794 fp->f_vnode = nd.ni_vp; 1795 fp->f_data = nd.ni_vp; 1796 fp->f_flag = flags; 1797 fp->f_ops = &vnops; 1798 fp->f_type = DTYPE_VNODE; 1799 VOP_UNLOCK(nd.ni_vp, 0, td); 1800 devnull = fd; 1801 fdrop(fp, td); 1802 } else { 1803 error = do_dup(td, DUP_FIXED, devnull, i, &retval); 1804 if (error != 0) 1805 break; 1806 } 1807 } 1808 return (error); 1809} 1810 1811/* 1812 * Internal form of close. 1813 * Decrement reference count on file structure. 1814 * Note: td may be NULL when closing a file 1815 * that was being passed in a message. 1816 */ 1817int 1818closef(fp, td) 1819 struct file *fp; 1820 struct thread *td; 1821{ 1822 struct vnode *vp; 1823 struct flock lf; 1824 struct filedesc_to_leader *fdtol; 1825 struct filedesc *fdp; 1826 1827 if (fp == NULL) 1828 return (0); 1829 /* 1830 * POSIX record locking dictates that any close releases ALL 1831 * locks owned by this process. This is handled by setting 1832 * a flag in the unlock to free ONLY locks obeying POSIX 1833 * semantics, and not to free BSD-style file locks. 1834 * If the descriptor was in a message, POSIX-style locks 1835 * aren't passed with the descriptor. 1836 */ 1837 if (td != NULL && 1838 fp->f_type == DTYPE_VNODE) { 1839 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1840 lf.l_whence = SEEK_SET; 1841 lf.l_start = 0; 1842 lf.l_len = 0; 1843 lf.l_type = F_UNLCK; 1844 vp = fp->f_vnode; 1845 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader, 1846 F_UNLCK, &lf, F_POSIX); 1847 } 1848 fdtol = td->td_proc->p_fdtol; 1849 if (fdtol != NULL) { 1850 /* 1851 * Handle special case where file descriptor table 1852 * is shared between multiple process leaders. 1853 */ 1854 fdp = td->td_proc->p_fd; 1855 FILEDESC_LOCK(fdp); 1856 for (fdtol = fdtol->fdl_next; 1857 fdtol != td->td_proc->p_fdtol; 1858 fdtol = fdtol->fdl_next) { 1859 if ((fdtol->fdl_leader->p_flag & 1860 P_ADVLOCK) == 0) 1861 continue; 1862 fdtol->fdl_holdcount++; 1863 FILEDESC_UNLOCK(fdp); 1864 lf.l_whence = SEEK_SET; 1865 lf.l_start = 0; 1866 lf.l_len = 0; 1867 lf.l_type = F_UNLCK; 1868 vp = fp->f_vnode; 1869 (void) VOP_ADVLOCK(vp, 1870 (caddr_t)fdtol->fdl_leader, 1871 F_UNLCK, &lf, F_POSIX); 1872 FILEDESC_LOCK(fdp); 1873 fdtol->fdl_holdcount--; 1874 if (fdtol->fdl_holdcount == 0 && 1875 fdtol->fdl_wakeup != 0) { 1876 fdtol->fdl_wakeup = 0; 1877 wakeup(fdtol); 1878 } 1879 } 1880 FILEDESC_UNLOCK(fdp); 1881 } 1882 } 1883 return (fdrop(fp, td)); 1884} 1885 1886/* 1887 * Drop reference on struct file passed in, may call closef if the 1888 * reference hits zero. 1889 */ 1890int 1891fdrop(fp, td) 1892 struct file *fp; 1893 struct thread *td; 1894{ 1895 1896 FILE_LOCK(fp); 1897 return (fdrop_locked(fp, td)); 1898} 1899 1900/* 1901 * Extract the file pointer associated with the specified descriptor for 1902 * the current user process. 1903 * 1904 * If the descriptor doesn't exist, EBADF is returned. 1905 * 1906 * If the descriptor exists but doesn't match 'flags' then 1907 * return EBADF for read attempts and EINVAL for write attempts. 1908 * 1909 * If 'hold' is set (non-zero) the file's refcount will be bumped on return. 1910 * It should be droped with fdrop(). 1911 * If it is not set, then the refcount will not be bumped however the 1912 * thread's filedesc struct will be returned locked (for fgetsock). 1913 * 1914 * If an error occured the non-zero error is returned and *fpp is set to NULL. 1915 * Otherwise *fpp is set and zero is returned. 1916 */ 1917static __inline int 1918_fget(struct thread *td, int fd, struct file **fpp, int flags, int hold) 1919{ 1920 struct filedesc *fdp; 1921 struct file *fp; 1922 1923 *fpp = NULL; 1924 if (td == NULL || (fdp = td->td_proc->p_fd) == NULL) 1925 return (EBADF); 1926 FILEDESC_LOCK(fdp); 1927 if ((fp = fget_locked(fdp, fd)) == NULL || fp->f_ops == &badfileops) { 1928 FILEDESC_UNLOCK(fdp); 1929 return (EBADF); 1930 } 1931 1932 /* 1933 * Note: FREAD failures returns EBADF to maintain backwards 1934 * compatibility with what routines returned before. 1935 * 1936 * Only one flag, or 0, may be specified. 1937 */ 1938 if (flags == FREAD && (fp->f_flag & FREAD) == 0) { 1939 FILEDESC_UNLOCK(fdp); 1940 return (EBADF); 1941 } 1942 if (flags == FWRITE && (fp->f_flag & FWRITE) == 0) { 1943 FILEDESC_UNLOCK(fdp); 1944 return (EINVAL); 1945 } 1946 if (hold) { 1947 fhold(fp); 1948 FILEDESC_UNLOCK(fdp); 1949 } 1950 *fpp = fp; 1951 return (0); 1952} 1953 1954int 1955fget(struct thread *td, int fd, struct file **fpp) 1956{ 1957 1958 return(_fget(td, fd, fpp, 0, 1)); 1959} 1960 1961int 1962fget_read(struct thread *td, int fd, struct file **fpp) 1963{ 1964 1965 return(_fget(td, fd, fpp, FREAD, 1)); 1966} 1967 1968int 1969fget_write(struct thread *td, int fd, struct file **fpp) 1970{ 1971 1972 return(_fget(td, fd, fpp, FWRITE, 1)); 1973} 1974 1975/* 1976 * Like fget() but loads the underlying vnode, or returns an error if 1977 * the descriptor does not represent a vnode. Note that pipes use vnodes 1978 * but never have VM objects (so VOP_GETVOBJECT() calls will return an 1979 * error). The returned vnode will be vref()d. 1980 */ 1981static __inline int 1982_fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags) 1983{ 1984 struct file *fp; 1985 int error; 1986 1987 GIANT_REQUIRED; /* VFS */ 1988 1989 *vpp = NULL; 1990 if ((error = _fget(td, fd, &fp, 0, 0)) != 0) 1991 return (error); 1992 if (fp->f_vnode == NULL) { 1993 error = EINVAL; 1994 } else { 1995 *vpp = fp->f_vnode; 1996 vref(*vpp); 1997 } 1998 FILEDESC_UNLOCK(td->td_proc->p_fd); 1999 return (error); 2000} 2001 2002int 2003fgetvp(struct thread *td, int fd, struct vnode **vpp) 2004{ 2005 2006 return (_fgetvp(td, fd, vpp, 0)); 2007} 2008 2009int 2010fgetvp_read(struct thread *td, int fd, struct vnode **vpp) 2011{ 2012 2013 return (_fgetvp(td, fd, vpp, FREAD)); 2014} 2015 2016int 2017fgetvp_write(struct thread *td, int fd, struct vnode **vpp) 2018{ 2019 2020 return (_fgetvp(td, fd, vpp, FWRITE)); 2021} 2022 2023/* 2024 * Like fget() but loads the underlying socket, or returns an error if 2025 * the descriptor does not represent a socket. 2026 * 2027 * We bump the ref count on the returned socket. XXX Also obtain the SX 2028 * lock in the future. 2029 */ 2030int 2031fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp) 2032{ 2033 struct file *fp; 2034 int error; 2035 2036 NET_ASSERT_GIANT(); 2037 2038 *spp = NULL; 2039 if (fflagp != NULL) 2040 *fflagp = 0; 2041 if ((error = _fget(td, fd, &fp, 0, 0)) != 0) 2042 return (error); 2043 if (fp->f_type != DTYPE_SOCKET) { 2044 error = ENOTSOCK; 2045 } else { 2046 *spp = fp->f_data; 2047 if (fflagp) 2048 *fflagp = fp->f_flag; 2049 SOCK_LOCK(*spp); 2050 soref(*spp); 2051 SOCK_UNLOCK(*spp); 2052 } 2053 FILEDESC_UNLOCK(td->td_proc->p_fd); 2054 return (error); 2055} 2056 2057/* 2058 * Drop the reference count on the the socket and XXX release the SX lock in 2059 * the future. The last reference closes the socket. 2060 */ 2061void 2062fputsock(struct socket *so) 2063{ 2064 2065 NET_ASSERT_GIANT(); 2066 SOCK_LOCK(so); 2067 sorele(so); 2068} 2069 2070/* 2071 * Drop reference on struct file passed in, may call closef if the 2072 * reference hits zero. 2073 * Expects struct file locked, and will unlock it. 2074 */ 2075int 2076fdrop_locked(fp, td) 2077 struct file *fp; 2078 struct thread *td; 2079{ 2080 int error; 2081 2082 FILE_LOCK_ASSERT(fp, MA_OWNED); 2083 2084 if (--fp->f_count > 0) { 2085 FILE_UNLOCK(fp); 2086 return (0); 2087 } 2088 /* We have the last ref so we can proceed without the file lock. */ 2089 FILE_UNLOCK(fp); 2090 if (fp->f_count < 0) 2091 panic("fdrop: count < 0"); 2092 if (fp->f_ops != &badfileops) 2093 error = fo_close(fp, td); 2094 else 2095 error = 0; 2096 ffree(fp); 2097 return (error); 2098} 2099 2100/* 2101 * Apply an advisory lock on a file descriptor. 2102 * 2103 * Just attempt to get a record lock of the requested type on 2104 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2105 */ 2106#ifndef _SYS_SYSPROTO_H_ 2107struct flock_args { 2108 int fd; 2109 int how; 2110}; 2111#endif 2112/* 2113 * MPSAFE 2114 */ 2115/* ARGSUSED */ 2116int 2117flock(td, uap) 2118 struct thread *td; 2119 struct flock_args *uap; 2120{ 2121 struct file *fp; 2122 struct vnode *vp; 2123 struct flock lf; 2124 int error; 2125 2126 if ((error = fget(td, uap->fd, &fp)) != 0) 2127 return (error); 2128 if (fp->f_type != DTYPE_VNODE) { 2129 fdrop(fp, td); 2130 return (EOPNOTSUPP); 2131 } 2132 2133 mtx_lock(&Giant); 2134 vp = fp->f_vnode; 2135 lf.l_whence = SEEK_SET; 2136 lf.l_start = 0; 2137 lf.l_len = 0; 2138 if (uap->how & LOCK_UN) { 2139 lf.l_type = F_UNLCK; 2140 FILE_LOCK(fp); 2141 fp->f_flag &= ~FHASLOCK; 2142 FILE_UNLOCK(fp); 2143 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 2144 goto done2; 2145 } 2146 if (uap->how & LOCK_EX) 2147 lf.l_type = F_WRLCK; 2148 else if (uap->how & LOCK_SH) 2149 lf.l_type = F_RDLCK; 2150 else { 2151 error = EBADF; 2152 goto done2; 2153 } 2154 FILE_LOCK(fp); 2155 fp->f_flag |= FHASLOCK; 2156 FILE_UNLOCK(fp); 2157 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 2158 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT); 2159done2: 2160 fdrop(fp, td); 2161 mtx_unlock(&Giant); 2162 return (error); 2163} 2164 2165/* 2166 * File Descriptor pseudo-device driver (/dev/fd/). 2167 * 2168 * Opening minor device N dup()s the file (if any) connected to file 2169 * descriptor N belonging to the calling process. Note that this driver 2170 * consists of only the ``open()'' routine, because all subsequent 2171 * references to this file will be direct to the other driver. 2172 */ 2173/* ARGSUSED */ 2174static int 2175fdopen(dev, mode, type, td) 2176 struct cdev *dev; 2177 int mode, type; 2178 struct thread *td; 2179{ 2180 2181 /* 2182 * XXX Kludge: set curthread->td_dupfd to contain the value of the 2183 * the file descriptor being sought for duplication. The error 2184 * return ensures that the vnode for this device will be released 2185 * by vn_open. Open will detect this special error and take the 2186 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 2187 * will simply report the error. 2188 */ 2189 td->td_dupfd = dev2unit(dev); 2190 return (ENODEV); 2191} 2192 2193/* 2194 * Duplicate the specified descriptor to a free descriptor. 2195 */ 2196int 2197dupfdopen(td, fdp, indx, dfd, mode, error) 2198 struct thread *td; 2199 struct filedesc *fdp; 2200 int indx, dfd; 2201 int mode; 2202 int error; 2203{ 2204 struct file *wfp; 2205 struct file *fp; 2206 2207 /* 2208 * If the to-be-dup'd fd number is greater than the allowed number 2209 * of file descriptors, or the fd to be dup'd has already been 2210 * closed, then reject. 2211 */ 2212 FILEDESC_LOCK(fdp); 2213 if (dfd < 0 || dfd >= fdp->fd_nfiles || 2214 (wfp = fdp->fd_ofiles[dfd]) == NULL) { 2215 FILEDESC_UNLOCK(fdp); 2216 return (EBADF); 2217 } 2218 2219 /* 2220 * There are two cases of interest here. 2221 * 2222 * For ENODEV simply dup (dfd) to file descriptor 2223 * (indx) and return. 2224 * 2225 * For ENXIO steal away the file structure from (dfd) and 2226 * store it in (indx). (dfd) is effectively closed by 2227 * this operation. 2228 * 2229 * Any other error code is just returned. 2230 */ 2231 switch (error) { 2232 case ENODEV: 2233 /* 2234 * Check that the mode the file is being opened for is a 2235 * subset of the mode of the existing descriptor. 2236 */ 2237 FILE_LOCK(wfp); 2238 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2239 FILE_UNLOCK(wfp); 2240 FILEDESC_UNLOCK(fdp); 2241 return (EACCES); 2242 } 2243 fp = fdp->fd_ofiles[indx]; 2244 fdp->fd_ofiles[indx] = wfp; 2245 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2246 if (fp == NULL) 2247 fdused(fdp, indx); 2248 fhold_locked(wfp); 2249 FILE_UNLOCK(wfp); 2250 if (fp != NULL) 2251 FILE_LOCK(fp); 2252 FILEDESC_UNLOCK(fdp); 2253 /* 2254 * We now own the reference to fp that the ofiles[] array 2255 * used to own. Release it. 2256 */ 2257 if (fp != NULL) 2258 fdrop_locked(fp, td); 2259 return (0); 2260 2261 case ENXIO: 2262 /* 2263 * Steal away the file pointer from dfd and stuff it into indx. 2264 */ 2265 fp = fdp->fd_ofiles[indx]; 2266 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd]; 2267 fdp->fd_ofiles[dfd] = NULL; 2268 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2269 fdp->fd_ofileflags[dfd] = 0; 2270 fdunused(fdp, dfd); 2271 if (fp == NULL) 2272 fdused(fdp, indx); 2273 if (fp != NULL) 2274 FILE_LOCK(fp); 2275 FILEDESC_UNLOCK(fdp); 2276 2277 /* 2278 * we now own the reference to fp that the ofiles[] array 2279 * used to own. Release it. 2280 */ 2281 if (fp != NULL) 2282 fdrop_locked(fp, td); 2283 return (0); 2284 2285 default: 2286 FILEDESC_UNLOCK(fdp); 2287 return (error); 2288 } 2289 /* NOTREACHED */ 2290} 2291 2292struct filedesc_to_leader * 2293filedesc_to_leader_alloc(struct filedesc_to_leader *old, 2294 struct filedesc *fdp, 2295 struct proc *leader) 2296{ 2297 struct filedesc_to_leader *fdtol; 2298 2299 MALLOC(fdtol, struct filedesc_to_leader *, 2300 sizeof(struct filedesc_to_leader), 2301 M_FILEDESC_TO_LEADER, 2302 M_WAITOK); 2303 fdtol->fdl_refcount = 1; 2304 fdtol->fdl_holdcount = 0; 2305 fdtol->fdl_wakeup = 0; 2306 fdtol->fdl_leader = leader; 2307 if (old != NULL) { 2308 FILEDESC_LOCK(fdp); 2309 fdtol->fdl_next = old->fdl_next; 2310 fdtol->fdl_prev = old; 2311 old->fdl_next = fdtol; 2312 fdtol->fdl_next->fdl_prev = fdtol; 2313 FILEDESC_UNLOCK(fdp); 2314 } else { 2315 fdtol->fdl_next = fdtol; 2316 fdtol->fdl_prev = fdtol; 2317 } 2318 return (fdtol); 2319} 2320 2321/* 2322 * Get file structures. 2323 */ 2324static int 2325sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2326{ 2327 struct xfile xf; 2328 struct filedesc *fdp; 2329 struct file *fp; 2330 struct proc *p; 2331 int error, n; 2332 2333 /* 2334 * Note: because the number of file descriptors is calculated 2335 * in different ways for sizing vs returning the data, 2336 * there is information leakage from the first loop. However, 2337 * it is of a similar order of magnitude to the leakage from 2338 * global system statistics such as kern.openfiles. 2339 */ 2340 error = sysctl_wire_old_buffer(req, 0); 2341 if (error != 0) 2342 return (error); 2343 if (req->oldptr == NULL) { 2344 n = 16; /* A slight overestimate. */ 2345 sx_slock(&filelist_lock); 2346 LIST_FOREACH(fp, &filehead, f_list) { 2347 /* 2348 * We should grab the lock, but this is an 2349 * estimate, so does it really matter? 2350 */ 2351 /* mtx_lock(fp->f_mtxp); */ 2352 n += fp->f_count; 2353 /* mtx_unlock(f->f_mtxp); */ 2354 } 2355 sx_sunlock(&filelist_lock); 2356 return (SYSCTL_OUT(req, 0, n * sizeof(xf))); 2357 } 2358 error = 0; 2359 bzero(&xf, sizeof(xf)); 2360 xf.xf_size = sizeof(xf); 2361 sx_slock(&allproc_lock); 2362 LIST_FOREACH(p, &allproc, p_list) { 2363 PROC_LOCK(p); 2364 if (p_cansee(req->td, p) != 0) { 2365 PROC_UNLOCK(p); 2366 continue; 2367 } 2368 xf.xf_pid = p->p_pid; 2369 xf.xf_uid = p->p_ucred->cr_uid; 2370 PROC_UNLOCK(p); 2371 mtx_lock(&fdesc_mtx); 2372 if ((fdp = p->p_fd) == NULL) { 2373 mtx_unlock(&fdesc_mtx); 2374 continue; 2375 } 2376 FILEDESC_LOCK(fdp); 2377 for (n = 0; n < fdp->fd_nfiles; ++n) { 2378 if ((fp = fdp->fd_ofiles[n]) == NULL) 2379 continue; 2380 xf.xf_fd = n; 2381 xf.xf_file = fp; 2382 xf.xf_data = fp->f_data; 2383 xf.xf_vnode = fp->f_vnode; 2384 xf.xf_type = fp->f_type; 2385 xf.xf_count = fp->f_count; 2386 xf.xf_msgcount = fp->f_msgcount; 2387 xf.xf_offset = fp->f_offset; 2388 xf.xf_flag = fp->f_flag; 2389 error = SYSCTL_OUT(req, &xf, sizeof(xf)); 2390 if (error) 2391 break; 2392 } 2393 FILEDESC_UNLOCK(fdp); 2394 mtx_unlock(&fdesc_mtx); 2395 if (error) 2396 break; 2397 } 2398 sx_sunlock(&allproc_lock); 2399 return (error); 2400} 2401 2402SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2403 0, 0, sysctl_kern_file, "S,xfile", "Entire file table"); 2404 2405SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 2406 &maxfilesperproc, 0, "Maximum files allowed open per process"); 2407 2408SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 2409 &maxfiles, 0, "Maximum number of files"); 2410 2411SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 2412 &nfiles, 0, "System-wide number of open files"); 2413 2414static void 2415fildesc_drvinit(void *unused) 2416{ 2417 struct cdev *dev; 2418 2419 dev = make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "fd/0"); 2420 make_dev_alias(dev, "stdin"); 2421 dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1"); 2422 make_dev_alias(dev, "stdout"); 2423 dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2"); 2424 make_dev_alias(dev, "stderr"); 2425} 2426 2427static fo_rdwr_t badfo_readwrite; 2428static fo_ioctl_t badfo_ioctl; 2429static fo_poll_t badfo_poll; 2430static fo_kqfilter_t badfo_kqfilter; 2431static fo_stat_t badfo_stat; 2432static fo_close_t badfo_close; 2433 2434struct fileops badfileops = { 2435 .fo_read = badfo_readwrite, 2436 .fo_write = badfo_readwrite, 2437 .fo_ioctl = badfo_ioctl, 2438 .fo_poll = badfo_poll, 2439 .fo_kqfilter = badfo_kqfilter, 2440 .fo_stat = badfo_stat, 2441 .fo_close = badfo_close, 2442}; 2443 2444static int 2445badfo_readwrite(fp, uio, active_cred, flags, td) 2446 struct file *fp; 2447 struct uio *uio; 2448 struct ucred *active_cred; 2449 struct thread *td; 2450 int flags; 2451{ 2452 2453 return (EBADF); 2454} 2455 2456static int 2457badfo_ioctl(fp, com, data, active_cred, td) 2458 struct file *fp; 2459 u_long com; 2460 void *data; 2461 struct ucred *active_cred; 2462 struct thread *td; 2463{ 2464 2465 return (EBADF); 2466} 2467 2468static int 2469badfo_poll(fp, events, active_cred, td) 2470 struct file *fp; 2471 int events; 2472 struct ucred *active_cred; 2473 struct thread *td; 2474{ 2475 2476 return (0); 2477} 2478 2479static int 2480badfo_kqfilter(fp, kn) 2481 struct file *fp; 2482 struct knote *kn; 2483{ 2484 2485 return (0); 2486} 2487 2488static int 2489badfo_stat(fp, sb, active_cred, td) 2490 struct file *fp; 2491 struct stat *sb; 2492 struct ucred *active_cred; 2493 struct thread *td; 2494{ 2495 2496 return (EBADF); 2497} 2498 2499static int 2500badfo_close(fp, td) 2501 struct file *fp; 2502 struct thread *td; 2503{ 2504 2505 return (EBADF); 2506} 2507 2508SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, 2509 fildesc_drvinit,NULL) 2510 2511static void filelistinit(void *); 2512SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL) 2513 2514/* ARGSUSED*/ 2515static void 2516filelistinit(dummy) 2517 void *dummy; 2518{ 2519 2520 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL, 2521 NULL, NULL, UMA_ALIGN_PTR, 0); 2522 sx_init(&filelist_lock, "filelist lock"); 2523 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF); 2524} 2525