Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_descrip.c
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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: releng/6.1/sys/kern/kern_descrip.c 176272 2008-02-14 11:47:39Z simon $"); 39 40 #include "opt_compat.h" 41 #include "opt_ddb.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 46 #include <sys/conf.h> 47 #include <sys/fcntl.h> 48 #include <sys/file.h> 49 #include <sys/filedesc.h> 50 #include <sys/filio.h> 51 #include <sys/jail.h> 52 #include <sys/kernel.h> 53 #include <sys/limits.h> 54 #include <sys/lock.h> 55 #include <sys/malloc.h> 56 #include <sys/mount.h> 57 #include <sys/mutex.h> 58 #include <sys/namei.h> 59 #include <sys/proc.h> 60 #include <sys/resourcevar.h> 61 #include <sys/signalvar.h> 62 #include <sys/socketvar.h> 63 #include <sys/stat.h> 64 #include <sys/sx.h> 65 #include <sys/syscallsubr.h> 66 #include <sys/sysctl.h> 67 #include <sys/sysproto.h> 68 #include <sys/unistd.h> 69 #include <sys/vnode.h> 70 71 #include <vm/uma.h> 72 73 #include <ddb/ddb.h> 74 75 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 76 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 77 "file desc to leader structures"); 78 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 79 80 static uma_zone_t file_zone; 81 82 83 /* How to treat 'new' parameter when allocating a fd for do_dup(). */ 84 enum dup_type { DUP_VARIABLE, DUP_FIXED }; 85 86 static int do_dup(struct thread *td, enum dup_type type, int old, int new, 87 register_t *retval); 88 static int fd_first_free(struct filedesc *, int, int); 89 static int fd_last_used(struct filedesc *, int, int); 90 static void fdgrowtable(struct filedesc *, int); 91 static int fdrop_locked(struct file *fp, struct thread *td); 92 static void fdunused(struct filedesc *fdp, int fd); 93 static void fdused(struct filedesc *fdp, int fd); 94 95 /* 96 * A process is initially started out with NDFILE descriptors stored within 97 * this structure, selected to be enough for typical applications based on 98 * the historical limit of 20 open files (and the usage of descriptors by 99 * shells). If these descriptors are exhausted, a larger descriptor table 100 * may be allocated, up to a process' resource limit; the internal arrays 101 * are then unused. 102 */ 103 #define NDFILE 20 104 #define NDSLOTSIZE sizeof(NDSLOTTYPE) 105 #define NDENTRIES (NDSLOTSIZE * __CHAR_BIT) 106 #define NDSLOT(x) ((x) / NDENTRIES) 107 #define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES)) 108 #define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES) 109 110 /* 111 * Storage required per open file descriptor. 112 */ 113 #define OFILESIZE (sizeof(struct file *) + sizeof(char)) 114 115 /* 116 * Basic allocation of descriptors: 117 * one of the above, plus arrays for NDFILE descriptors. 118 */ 119 struct filedesc0 { 120 struct filedesc fd_fd; 121 /* 122 * These arrays are used when the number of open files is 123 * <= NDFILE, and are then pointed to by the pointers above. 124 */ 125 struct file *fd_dfiles[NDFILE]; 126 char fd_dfileflags[NDFILE]; 127 NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)]; 128 }; 129 130 /* 131 * Descriptor management. 132 */ 133 struct filelist filehead; /* head of list of open files */ 134 int openfiles; /* actual number of open files */ 135 struct sx filelist_lock; /* sx to protect filelist */ 136 struct mtx sigio_lock; /* mtx to protect pointers to sigio */ 137 138 /* A mutex to protect the association between a proc and filedesc. */ 139 static struct mtx fdesc_mtx; 140 141 /* 142 * Find the first zero bit in the given bitmap, starting at low and not 143 * exceeding size - 1. 144 */ 145 static int 146 fd_first_free(struct filedesc *fdp, int low, int size) 147 { 148 NDSLOTTYPE *map = fdp->fd_map; 149 NDSLOTTYPE mask; 150 int off, maxoff; 151 152 if (low >= size) 153 return (low); 154 155 off = NDSLOT(low); 156 if (low % NDENTRIES) { 157 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES))); 158 if ((mask &= ~map[off]) != 0UL) 159 return (off * NDENTRIES + ffsl(mask) - 1); 160 ++off; 161 } 162 for (maxoff = NDSLOTS(size); off < maxoff; ++off) 163 if (map[off] != ~0UL) 164 return (off * NDENTRIES + ffsl(~map[off]) - 1); 165 return (size); 166 } 167 168 /* 169 * Find the highest non-zero bit in the given bitmap, starting at low and 170 * not exceeding size - 1. 171 */ 172 static int 173 fd_last_used(struct filedesc *fdp, int low, int size) 174 { 175 NDSLOTTYPE *map = fdp->fd_map; 176 NDSLOTTYPE mask; 177 int off, minoff; 178 179 if (low >= size) 180 return (-1); 181 182 off = NDSLOT(size); 183 if (size % NDENTRIES) { 184 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES)); 185 if ((mask &= map[off]) != 0) 186 return (off * NDENTRIES + flsl(mask) - 1); 187 --off; 188 } 189 for (minoff = NDSLOT(low); off >= minoff; --off) 190 if (map[off] != 0) 191 return (off * NDENTRIES + flsl(map[off]) - 1); 192 return (low - 1); 193 } 194 195 static int 196 fdisused(struct filedesc *fdp, int fd) 197 { 198 KASSERT(fd >= 0 && fd < fdp->fd_nfiles, 199 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles)); 200 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0); 201 } 202 203 /* 204 * Mark a file descriptor as used. 205 */ 206 static void 207 fdused(struct filedesc *fdp, int fd) 208 { 209 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 210 KASSERT(!fdisused(fdp, fd), 211 ("fd already used")); 212 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd); 213 if (fd > fdp->fd_lastfile) 214 fdp->fd_lastfile = fd; 215 if (fd == fdp->fd_freefile) 216 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 217 } 218 219 /* 220 * Mark a file descriptor as unused. 221 */ 222 static void 223 fdunused(struct filedesc *fdp, int fd) 224 { 225 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 226 KASSERT(fdisused(fdp, fd), 227 ("fd is already unused")); 228 KASSERT(fdp->fd_ofiles[fd] == NULL, 229 ("fd is still in use")); 230 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd); 231 if (fd < fdp->fd_freefile) 232 fdp->fd_freefile = fd; 233 if (fd == fdp->fd_lastfile) 234 fdp->fd_lastfile = fd_last_used(fdp, 0, fd); 235 } 236 237 /* 238 * System calls on descriptors. 239 */ 240 #ifndef _SYS_SYSPROTO_H_ 241 struct getdtablesize_args { 242 int dummy; 243 }; 244 #endif 245 /* 246 * MPSAFE 247 */ 248 /* ARGSUSED */ 249 int 250 getdtablesize(struct thread *td, struct getdtablesize_args *uap) 251 { 252 struct proc *p = td->td_proc; 253 254 PROC_LOCK(p); 255 td->td_retval[0] = 256 min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 257 PROC_UNLOCK(p); 258 return (0); 259 } 260 261 /* 262 * Duplicate a file descriptor to a particular value. 263 * 264 * note: keep in mind that a potential race condition exists when closing 265 * descriptors from a shared descriptor table (via rfork). 266 */ 267 #ifndef _SYS_SYSPROTO_H_ 268 struct dup2_args { 269 u_int from; 270 u_int to; 271 }; 272 #endif 273 /* 274 * MPSAFE 275 */ 276 /* ARGSUSED */ 277 int 278 dup2(struct thread *td, struct dup2_args *uap) 279 { 280 281 return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to, 282 td->td_retval)); 283 } 284 285 /* 286 * Duplicate a file descriptor. 287 */ 288 #ifndef _SYS_SYSPROTO_H_ 289 struct dup_args { 290 u_int fd; 291 }; 292 #endif 293 /* 294 * MPSAFE 295 */ 296 /* ARGSUSED */ 297 int 298 dup(struct thread *td, struct dup_args *uap) 299 { 300 301 return (do_dup(td, DUP_VARIABLE, (int)uap->fd, 0, td->td_retval)); 302 } 303 304 /* 305 * The file control system call. 306 */ 307 #ifndef _SYS_SYSPROTO_H_ 308 struct fcntl_args { 309 int fd; 310 int cmd; 311 long arg; 312 }; 313 #endif 314 /* 315 * MPSAFE 316 */ 317 /* ARGSUSED */ 318 int 319 fcntl(struct thread *td, struct fcntl_args *uap) 320 { 321 struct flock fl; 322 intptr_t arg; 323 int error; 324 325 error = 0; 326 switch (uap->cmd) { 327 case F_GETLK: 328 case F_SETLK: 329 case F_SETLKW: 330 error = copyin((void *)(intptr_t)uap->arg, &fl, sizeof(fl)); 331 arg = (intptr_t)&fl; 332 break; 333 default: 334 arg = uap->arg; 335 break; 336 } 337 if (error) 338 return (error); 339 error = kern_fcntl(td, uap->fd, uap->cmd, arg); 340 if (error) 341 return (error); 342 if (uap->cmd == F_GETLK) 343 error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl)); 344 return (error); 345 } 346 347 int 348 kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) 349 { 350 struct filedesc *fdp; 351 struct flock *flp; 352 struct file *fp; 353 struct proc *p; 354 char *pop; 355 struct vnode *vp; 356 u_int newmin; 357 int error, flg, tmp; 358 int giant_locked; 359 360 /* 361 * XXXRW: Some fcntl() calls require Giant -- others don't. Try to 362 * avoid grabbing Giant for calls we know don't need it. 363 */ 364 switch (cmd) { 365 case F_DUPFD: 366 case F_GETFD: 367 case F_SETFD: 368 case F_GETFL: 369 giant_locked = 0; 370 break; 371 372 default: 373 giant_locked = 1; 374 mtx_lock(&Giant); 375 } 376 377 error = 0; 378 flg = F_POSIX; 379 p = td->td_proc; 380 fdp = p->p_fd; 381 FILEDESC_LOCK(fdp); 382 if ((unsigned)fd >= fdp->fd_nfiles || 383 (fp = fdp->fd_ofiles[fd]) == NULL) { 384 FILEDESC_UNLOCK(fdp); 385 error = EBADF; 386 goto done2; 387 } 388 pop = &fdp->fd_ofileflags[fd]; 389 390 switch (cmd) { 391 case F_DUPFD: 392 /* mtx_assert(&Giant, MA_NOTOWNED); */ 393 FILEDESC_UNLOCK(fdp); 394 newmin = arg; 395 PROC_LOCK(p); 396 if (newmin >= lim_cur(p, RLIMIT_NOFILE) || 397 newmin >= maxfilesperproc) { 398 PROC_UNLOCK(p); 399 error = EINVAL; 400 break; 401 } 402 PROC_UNLOCK(p); 403 error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval); 404 break; 405 406 case F_GETFD: 407 /* mtx_assert(&Giant, MA_NOTOWNED); */ 408 td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0; 409 FILEDESC_UNLOCK(fdp); 410 break; 411 412 case F_SETFD: 413 /* mtx_assert(&Giant, MA_NOTOWNED); */ 414 *pop = (*pop &~ UF_EXCLOSE) | 415 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0); 416 FILEDESC_UNLOCK(fdp); 417 break; 418 419 case F_GETFL: 420 /* mtx_assert(&Giant, MA_NOTOWNED); */ 421 FILE_LOCK(fp); 422 td->td_retval[0] = OFLAGS(fp->f_flag); 423 FILE_UNLOCK(fp); 424 FILEDESC_UNLOCK(fdp); 425 break; 426 427 case F_SETFL: 428 mtx_assert(&Giant, MA_OWNED); 429 FILE_LOCK(fp); 430 fhold_locked(fp); 431 fp->f_flag &= ~FCNTLFLAGS; 432 fp->f_flag |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS; 433 FILE_UNLOCK(fp); 434 FILEDESC_UNLOCK(fdp); 435 tmp = fp->f_flag & FNONBLOCK; 436 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 437 if (error) { 438 fdrop(fp, td); 439 break; 440 } 441 tmp = fp->f_flag & FASYNC; 442 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); 443 if (error == 0) { 444 fdrop(fp, td); 445 break; 446 } 447 FILE_LOCK(fp); 448 fp->f_flag &= ~FNONBLOCK; 449 FILE_UNLOCK(fp); 450 tmp = 0; 451 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 452 fdrop(fp, td); 453 break; 454 455 case F_GETOWN: 456 mtx_assert(&Giant, MA_OWNED); 457 fhold(fp); 458 FILEDESC_UNLOCK(fdp); 459 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td); 460 if (error == 0) 461 td->td_retval[0] = tmp; 462 fdrop(fp, td); 463 break; 464 465 case F_SETOWN: 466 mtx_assert(&Giant, MA_OWNED); 467 fhold(fp); 468 FILEDESC_UNLOCK(fdp); 469 tmp = arg; 470 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td); 471 fdrop(fp, td); 472 break; 473 474 case F_SETLKW: 475 mtx_assert(&Giant, MA_OWNED); 476 flg |= F_WAIT; 477 /* FALLTHROUGH F_SETLK */ 478 479 case F_SETLK: 480 mtx_assert(&Giant, MA_OWNED); 481 if (fp->f_type != DTYPE_VNODE) { 482 FILEDESC_UNLOCK(fdp); 483 error = EBADF; 484 break; 485 } 486 487 flp = (struct flock *)arg; 488 if (flp->l_whence == SEEK_CUR) { 489 if (fp->f_offset < 0 || 490 (flp->l_start > 0 && 491 fp->f_offset > OFF_MAX - flp->l_start)) { 492 FILEDESC_UNLOCK(fdp); 493 error = EOVERFLOW; 494 break; 495 } 496 flp->l_start += fp->f_offset; 497 } 498 499 /* 500 * VOP_ADVLOCK() may block. 501 */ 502 fhold(fp); 503 FILEDESC_UNLOCK(fdp); 504 vp = fp->f_vnode; 505 506 switch (flp->l_type) { 507 case F_RDLCK: 508 if ((fp->f_flag & FREAD) == 0) { 509 error = EBADF; 510 break; 511 } 512 PROC_LOCK(p->p_leader); 513 p->p_leader->p_flag |= P_ADVLOCK; 514 PROC_UNLOCK(p->p_leader); 515 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 516 flp, flg); 517 break; 518 case F_WRLCK: 519 if ((fp->f_flag & FWRITE) == 0) { 520 error = EBADF; 521 break; 522 } 523 PROC_LOCK(p->p_leader); 524 p->p_leader->p_flag |= P_ADVLOCK; 525 PROC_UNLOCK(p->p_leader); 526 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 527 flp, flg); 528 break; 529 case F_UNLCK: 530 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 531 flp, F_POSIX); 532 break; 533 default: 534 error = EINVAL; 535 break; 536 } 537 /* Check for race with close */ 538 FILEDESC_LOCK_FAST(fdp); 539 if ((unsigned) fd >= fdp->fd_nfiles || 540 fp != fdp->fd_ofiles[fd]) { 541 FILEDESC_UNLOCK_FAST(fdp); 542 flp->l_whence = SEEK_SET; 543 flp->l_start = 0; 544 flp->l_len = 0; 545 flp->l_type = F_UNLCK; 546 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 547 F_UNLCK, flp, F_POSIX); 548 } else 549 FILEDESC_UNLOCK_FAST(fdp); 550 fdrop(fp, td); 551 break; 552 553 case F_GETLK: 554 mtx_assert(&Giant, MA_OWNED); 555 if (fp->f_type != DTYPE_VNODE) { 556 FILEDESC_UNLOCK(fdp); 557 error = EBADF; 558 break; 559 } 560 flp = (struct flock *)arg; 561 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK && 562 flp->l_type != F_UNLCK) { 563 FILEDESC_UNLOCK(fdp); 564 error = EINVAL; 565 break; 566 } 567 if (flp->l_whence == SEEK_CUR) { 568 if ((flp->l_start > 0 && 569 fp->f_offset > OFF_MAX - flp->l_start) || 570 (flp->l_start < 0 && 571 fp->f_offset < OFF_MIN - flp->l_start)) { 572 FILEDESC_UNLOCK(fdp); 573 error = EOVERFLOW; 574 break; 575 } 576 flp->l_start += fp->f_offset; 577 } 578 /* 579 * VOP_ADVLOCK() may block. 580 */ 581 fhold(fp); 582 FILEDESC_UNLOCK(fdp); 583 vp = fp->f_vnode; 584 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp, 585 F_POSIX); 586 fdrop(fp, td); 587 break; 588 default: 589 FILEDESC_UNLOCK(fdp); 590 error = EINVAL; 591 break; 592 } 593 done2: 594 if (giant_locked) 595 mtx_unlock(&Giant); 596 return (error); 597 } 598 599 /* 600 * Common code for dup, dup2, and fcntl(F_DUPFD). 601 */ 602 static int 603 do_dup(struct thread *td, enum dup_type type, int old, int new, register_t *retval) 604 { 605 struct filedesc *fdp; 606 struct proc *p; 607 struct file *fp; 608 struct file *delfp; 609 int error, holdleaders, maxfd; 610 611 KASSERT((type == DUP_VARIABLE || type == DUP_FIXED), 612 ("invalid dup type %d", type)); 613 614 p = td->td_proc; 615 fdp = p->p_fd; 616 617 /* 618 * Verify we have a valid descriptor to dup from and possibly to 619 * dup to. 620 */ 621 if (old < 0 || new < 0) 622 return (EBADF); 623 PROC_LOCK(p); 624 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 625 PROC_UNLOCK(p); 626 if (new >= maxfd) 627 return (EMFILE); 628 629 FILEDESC_LOCK(fdp); 630 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) { 631 FILEDESC_UNLOCK(fdp); 632 return (EBADF); 633 } 634 if (type == DUP_FIXED && old == new) { 635 *retval = new; 636 FILEDESC_UNLOCK(fdp); 637 return (0); 638 } 639 fp = fdp->fd_ofiles[old]; 640 fhold(fp); 641 642 /* 643 * If the caller specified a file descriptor, make sure the file 644 * table is large enough to hold it, and grab it. Otherwise, just 645 * allocate a new descriptor the usual way. Since the filedesc 646 * lock may be temporarily dropped in the process, we have to look 647 * out for a race. 648 */ 649 if (type == DUP_FIXED) { 650 if (new >= fdp->fd_nfiles) 651 fdgrowtable(fdp, new + 1); 652 if (fdp->fd_ofiles[new] == NULL) 653 fdused(fdp, new); 654 } else { 655 if ((error = fdalloc(td, new, &new)) != 0) { 656 FILEDESC_UNLOCK(fdp); 657 fdrop(fp, td); 658 return (error); 659 } 660 } 661 662 /* 663 * If the old file changed out from under us then treat it as a 664 * bad file descriptor. Userland should do its own locking to 665 * avoid this case. 666 */ 667 if (fdp->fd_ofiles[old] != fp) { 668 /* we've allocated a descriptor which we won't use */ 669 if (fdp->fd_ofiles[new] == NULL) 670 fdunused(fdp, new); 671 FILEDESC_UNLOCK(fdp); 672 fdrop(fp, td); 673 return (EBADF); 674 } 675 KASSERT(old != new, 676 ("new fd is same as old")); 677 678 /* 679 * Save info on the descriptor being overwritten. We cannot close 680 * it without introducing an ownership race for the slot, since we 681 * need to drop the filedesc lock to call closef(). 682 * 683 * XXX this duplicates parts of close(). 684 */ 685 delfp = fdp->fd_ofiles[new]; 686 holdleaders = 0; 687 if (delfp != NULL) { 688 if (td->td_proc->p_fdtol != NULL) { 689 /* 690 * Ask fdfree() to sleep to ensure that all relevant 691 * process leaders can be traversed in closef(). 692 */ 693 fdp->fd_holdleaderscount++; 694 holdleaders = 1; 695 } 696 } 697 698 /* 699 * Duplicate the source descriptor 700 */ 701 fdp->fd_ofiles[new] = fp; 702 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE; 703 if (new > fdp->fd_lastfile) 704 fdp->fd_lastfile = new; 705 *retval = new; 706 707 /* 708 * If we dup'd over a valid file, we now own the reference to it 709 * and must dispose of it using closef() semantics (as if a 710 * close() were performed on it). 711 * 712 * XXX this duplicates parts of close(). 713 */ 714 if (delfp != NULL) { 715 knote_fdclose(td, new); 716 FILEDESC_UNLOCK(fdp); 717 (void) closef(delfp, td); 718 if (holdleaders) { 719 FILEDESC_LOCK_FAST(fdp); 720 fdp->fd_holdleaderscount--; 721 if (fdp->fd_holdleaderscount == 0 && 722 fdp->fd_holdleaderswakeup != 0) { 723 fdp->fd_holdleaderswakeup = 0; 724 wakeup(&fdp->fd_holdleaderscount); 725 } 726 FILEDESC_UNLOCK_FAST(fdp); 727 } 728 } else { 729 FILEDESC_UNLOCK(fdp); 730 } 731 return (0); 732 } 733 734 /* 735 * If sigio is on the list associated with a process or process group, 736 * disable signalling from the device, remove sigio from the list and 737 * free sigio. 738 */ 739 void 740 funsetown(struct sigio **sigiop) 741 { 742 struct sigio *sigio; 743 744 SIGIO_LOCK(); 745 sigio = *sigiop; 746 if (sigio == NULL) { 747 SIGIO_UNLOCK(); 748 return; 749 } 750 *(sigio->sio_myref) = NULL; 751 if ((sigio)->sio_pgid < 0) { 752 struct pgrp *pg = (sigio)->sio_pgrp; 753 PGRP_LOCK(pg); 754 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 755 sigio, sio_pgsigio); 756 PGRP_UNLOCK(pg); 757 } else { 758 struct proc *p = (sigio)->sio_proc; 759 PROC_LOCK(p); 760 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 761 sigio, sio_pgsigio); 762 PROC_UNLOCK(p); 763 } 764 SIGIO_UNLOCK(); 765 crfree(sigio->sio_ucred); 766 FREE(sigio, M_SIGIO); 767 } 768 769 /* 770 * Free a list of sigio structures. 771 * We only need to lock the SIGIO_LOCK because we have made ourselves 772 * inaccessible to callers of fsetown and therefore do not need to lock 773 * the proc or pgrp struct for the list manipulation. 774 */ 775 void 776 funsetownlst(struct sigiolst *sigiolst) 777 { 778 struct proc *p; 779 struct pgrp *pg; 780 struct sigio *sigio; 781 782 sigio = SLIST_FIRST(sigiolst); 783 if (sigio == NULL) 784 return; 785 p = NULL; 786 pg = NULL; 787 788 /* 789 * Every entry of the list should belong 790 * to a single proc or pgrp. 791 */ 792 if (sigio->sio_pgid < 0) { 793 pg = sigio->sio_pgrp; 794 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED); 795 } else /* if (sigio->sio_pgid > 0) */ { 796 p = sigio->sio_proc; 797 PROC_LOCK_ASSERT(p, MA_NOTOWNED); 798 } 799 800 SIGIO_LOCK(); 801 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) { 802 *(sigio->sio_myref) = NULL; 803 if (pg != NULL) { 804 KASSERT(sigio->sio_pgid < 0, 805 ("Proc sigio in pgrp sigio list")); 806 KASSERT(sigio->sio_pgrp == pg, 807 ("Bogus pgrp in sigio list")); 808 PGRP_LOCK(pg); 809 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio, 810 sio_pgsigio); 811 PGRP_UNLOCK(pg); 812 } else /* if (p != NULL) */ { 813 KASSERT(sigio->sio_pgid > 0, 814 ("Pgrp sigio in proc sigio list")); 815 KASSERT(sigio->sio_proc == p, 816 ("Bogus proc in sigio list")); 817 PROC_LOCK(p); 818 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, 819 sio_pgsigio); 820 PROC_UNLOCK(p); 821 } 822 SIGIO_UNLOCK(); 823 crfree(sigio->sio_ucred); 824 FREE(sigio, M_SIGIO); 825 SIGIO_LOCK(); 826 } 827 SIGIO_UNLOCK(); 828 } 829 830 /* 831 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 832 * 833 * After permission checking, add a sigio structure to the sigio list for 834 * the process or process group. 835 */ 836 int 837 fsetown(pid_t pgid, struct sigio **sigiop) 838 { 839 struct proc *proc; 840 struct pgrp *pgrp; 841 struct sigio *sigio; 842 int ret; 843 844 if (pgid == 0) { 845 funsetown(sigiop); 846 return (0); 847 } 848 849 ret = 0; 850 851 /* Allocate and fill in the new sigio out of locks. */ 852 MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK); 853 sigio->sio_pgid = pgid; 854 sigio->sio_ucred = crhold(curthread->td_ucred); 855 sigio->sio_myref = sigiop; 856 857 sx_slock(&proctree_lock); 858 if (pgid > 0) { 859 proc = pfind(pgid); 860 if (proc == NULL) { 861 ret = ESRCH; 862 goto fail; 863 } 864 865 /* 866 * Policy - Don't allow a process to FSETOWN a process 867 * in another session. 868 * 869 * Remove this test to allow maximum flexibility or 870 * restrict FSETOWN to the current process or process 871 * group for maximum safety. 872 */ 873 PROC_UNLOCK(proc); 874 if (proc->p_session != curthread->td_proc->p_session) { 875 ret = EPERM; 876 goto fail; 877 } 878 879 pgrp = NULL; 880 } else /* if (pgid < 0) */ { 881 pgrp = pgfind(-pgid); 882 if (pgrp == NULL) { 883 ret = ESRCH; 884 goto fail; 885 } 886 PGRP_UNLOCK(pgrp); 887 888 /* 889 * Policy - Don't allow a process to FSETOWN a process 890 * in another session. 891 * 892 * Remove this test to allow maximum flexibility or 893 * restrict FSETOWN to the current process or process 894 * group for maximum safety. 895 */ 896 if (pgrp->pg_session != curthread->td_proc->p_session) { 897 ret = EPERM; 898 goto fail; 899 } 900 901 proc = NULL; 902 } 903 funsetown(sigiop); 904 if (pgid > 0) { 905 PROC_LOCK(proc); 906 /* 907 * Since funsetownlst() is called without the proctree 908 * locked, we need to check for P_WEXIT. 909 * XXX: is ESRCH correct? 910 */ 911 if ((proc->p_flag & P_WEXIT) != 0) { 912 PROC_UNLOCK(proc); 913 ret = ESRCH; 914 goto fail; 915 } 916 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 917 sigio->sio_proc = proc; 918 PROC_UNLOCK(proc); 919 } else { 920 PGRP_LOCK(pgrp); 921 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 922 sigio->sio_pgrp = pgrp; 923 PGRP_UNLOCK(pgrp); 924 } 925 sx_sunlock(&proctree_lock); 926 SIGIO_LOCK(); 927 *sigiop = sigio; 928 SIGIO_UNLOCK(); 929 return (0); 930 931 fail: 932 sx_sunlock(&proctree_lock); 933 crfree(sigio->sio_ucred); 934 FREE(sigio, M_SIGIO); 935 return (ret); 936 } 937 938 /* 939 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 940 */ 941 pid_t 942 fgetown(sigiop) 943 struct sigio **sigiop; 944 { 945 pid_t pgid; 946 947 SIGIO_LOCK(); 948 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0; 949 SIGIO_UNLOCK(); 950 return (pgid); 951 } 952 953 /* 954 * Close a file descriptor. 955 */ 956 #ifndef _SYS_SYSPROTO_H_ 957 struct close_args { 958 int fd; 959 }; 960 #endif 961 /* 962 * MPSAFE 963 */ 964 /* ARGSUSED */ 965 int 966 close(td, uap) 967 struct thread *td; 968 struct close_args *uap; 969 { 970 struct filedesc *fdp; 971 struct file *fp; 972 int fd, error; 973 int holdleaders; 974 975 fd = uap->fd; 976 error = 0; 977 holdleaders = 0; 978 fdp = td->td_proc->p_fd; 979 FILEDESC_LOCK(fdp); 980 if ((unsigned)fd >= fdp->fd_nfiles || 981 (fp = fdp->fd_ofiles[fd]) == NULL) { 982 FILEDESC_UNLOCK(fdp); 983 return (EBADF); 984 } 985 fdp->fd_ofiles[fd] = NULL; 986 fdp->fd_ofileflags[fd] = 0; 987 fdunused(fdp, fd); 988 if (td->td_proc->p_fdtol != NULL) { 989 /* 990 * Ask fdfree() to sleep to ensure that all relevant 991 * process leaders can be traversed in closef(). 992 */ 993 fdp->fd_holdleaderscount++; 994 holdleaders = 1; 995 } 996 997 /* 998 * We now hold the fp reference that used to be owned by the descriptor 999 * array. 1000 * We have to unlock the FILEDESC *AFTER* knote_fdclose to prevent a 1001 * race of the fd getting opened, a knote added, and deleteing a knote 1002 * for the new fd. 1003 */ 1004 knote_fdclose(td, fd); 1005 FILEDESC_UNLOCK(fdp); 1006 1007 error = closef(fp, td); 1008 if (holdleaders) { 1009 FILEDESC_LOCK_FAST(fdp); 1010 fdp->fd_holdleaderscount--; 1011 if (fdp->fd_holdleaderscount == 0 && 1012 fdp->fd_holdleaderswakeup != 0) { 1013 fdp->fd_holdleaderswakeup = 0; 1014 wakeup(&fdp->fd_holdleaderscount); 1015 } 1016 FILEDESC_UNLOCK_FAST(fdp); 1017 } 1018 return (error); 1019 } 1020 1021 #if defined(COMPAT_43) 1022 /* 1023 * Return status information about a file descriptor. 1024 */ 1025 #ifndef _SYS_SYSPROTO_H_ 1026 struct ofstat_args { 1027 int fd; 1028 struct ostat *sb; 1029 }; 1030 #endif 1031 /* 1032 * MPSAFE 1033 */ 1034 /* ARGSUSED */ 1035 int 1036 ofstat(struct thread *td, struct ofstat_args *uap) 1037 { 1038 struct ostat oub; 1039 struct stat ub; 1040 int error; 1041 1042 error = kern_fstat(td, uap->fd, &ub); 1043 if (error == 0) { 1044 cvtstat(&ub, &oub); 1045 error = copyout(&oub, uap->sb, sizeof(oub)); 1046 } 1047 return (error); 1048 } 1049 #endif /* COMPAT_43 */ 1050 1051 /* 1052 * Return status information about a file descriptor. 1053 */ 1054 #ifndef _SYS_SYSPROTO_H_ 1055 struct fstat_args { 1056 int fd; 1057 struct stat *sb; 1058 }; 1059 #endif 1060 /* 1061 * MPSAFE 1062 */ 1063 /* ARGSUSED */ 1064 int 1065 fstat(struct thread *td, struct fstat_args *uap) 1066 { 1067 struct stat ub; 1068 int error; 1069 1070 error = kern_fstat(td, uap->fd, &ub); 1071 if (error == 0) 1072 error = copyout(&ub, uap->sb, sizeof(ub)); 1073 return (error); 1074 } 1075 1076 int 1077 kern_fstat(struct thread *td, int fd, struct stat *sbp) 1078 { 1079 struct file *fp; 1080 int error; 1081 1082 if ((error = fget(td, fd, &fp)) != 0) 1083 return (error); 1084 error = fo_stat(fp, sbp, td->td_ucred, td); 1085 fdrop(fp, td); 1086 return (error); 1087 } 1088 1089 /* 1090 * Return status information about a file descriptor. 1091 */ 1092 #ifndef _SYS_SYSPROTO_H_ 1093 struct nfstat_args { 1094 int fd; 1095 struct nstat *sb; 1096 }; 1097 #endif 1098 /* 1099 * MPSAFE 1100 */ 1101 /* ARGSUSED */ 1102 int 1103 nfstat(struct thread *td, struct nfstat_args *uap) 1104 { 1105 struct nstat nub; 1106 struct stat ub; 1107 int error; 1108 1109 error = kern_fstat(td, uap->fd, &ub); 1110 if (error == 0) { 1111 cvtnstat(&ub, &nub); 1112 error = copyout(&nub, uap->sb, sizeof(nub)); 1113 } 1114 return (error); 1115 } 1116 1117 /* 1118 * Return pathconf information about a file descriptor. 1119 */ 1120 #ifndef _SYS_SYSPROTO_H_ 1121 struct fpathconf_args { 1122 int fd; 1123 int name; 1124 }; 1125 #endif 1126 /* 1127 * MPSAFE 1128 */ 1129 /* ARGSUSED */ 1130 int 1131 fpathconf(struct thread *td, struct fpathconf_args *uap) 1132 { 1133 struct file *fp; 1134 struct vnode *vp; 1135 int error; 1136 1137 if ((error = fget(td, uap->fd, &fp)) != 0) 1138 return (error); 1139 1140 /* If asynchronous I/O is available, it works for all descriptors. */ 1141 if (uap->name == _PC_ASYNC_IO) { 1142 td->td_retval[0] = async_io_version; 1143 goto out; 1144 } 1145 vp = fp->f_vnode; 1146 if (vp != NULL) { 1147 int vfslocked; 1148 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 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 VFS_UNLOCK_GIANT(vfslocked); 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 } 1163 out: 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 * returning. 1172 */ 1173 static void 1174 fdgrowtable(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 */ 1235 int 1236 fdalloc(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 if (fdp->fd_freefile > minfd) 1245 minfd = fdp->fd_freefile; 1246 1247 PROC_LOCK(p); 1248 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1249 PROC_UNLOCK(p); 1250 1251 /* 1252 * Search the bitmap for a free descriptor. If none is found, try 1253 * to grow the file table. Keep at it until we either get a file 1254 * descriptor or run into process or system limits; fdgrowtable() 1255 * may drop the filedesc lock, so we're in a race. 1256 */ 1257 for (;;) { 1258 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); 1259 if (fd >= maxfd) 1260 return (EMFILE); 1261 if (fd < fdp->fd_nfiles) 1262 break; 1263 fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd)); 1264 } 1265 1266 /* 1267 * Perform some sanity checks, then mark the file descriptor as 1268 * used and return it to the caller. 1269 */ 1270 KASSERT(!fdisused(fdp, fd), 1271 ("fd_first_free() returned non-free descriptor")); 1272 KASSERT(fdp->fd_ofiles[fd] == NULL, 1273 ("free descriptor isn't")); 1274 fdp->fd_ofileflags[fd] = 0; /* XXX needed? */ 1275 fdused(fdp, fd); 1276 *result = fd; 1277 return (0); 1278 } 1279 1280 /* 1281 * Check to see whether n user file descriptors 1282 * are available to the process p. 1283 */ 1284 int 1285 fdavail(struct thread *td, 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 * preempted and the entry in the descriptor table closed after 1314 * we release the FILEDESC lock. 1315 */ 1316 int 1317 falloc(struct thread *td, struct file **resultfp, int *resultfd) 1318 { 1319 struct proc *p = td->td_proc; 1320 struct file *fp, *fq; 1321 int error, i; 1322 int maxuserfiles = maxfiles - (maxfiles / 20); 1323 static struct timeval lastfail; 1324 static int curfail; 1325 1326 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO); 1327 sx_xlock(&filelist_lock); 1328 if ((openfiles >= maxuserfiles && (td->td_ucred->cr_ruid != 0 || 1329 jailed(td->td_ucred))) || openfiles >= maxfiles) { 1330 if (ppsratecheck(&lastfail, &curfail, 1)) { 1331 printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n", 1332 td->td_ucred->cr_ruid); 1333 } 1334 sx_xunlock(&filelist_lock); 1335 uma_zfree(file_zone, fp); 1336 return (ENFILE); 1337 } 1338 openfiles++; 1339 1340 /* 1341 * If the process has file descriptor zero open, add the new file 1342 * descriptor to the list of open files at that point, otherwise 1343 * put it at the front of the list of open files. 1344 */ 1345 fp->f_mtxp = mtx_pool_alloc(mtxpool_sleep); 1346 fp->f_count = 1; 1347 if (resultfp) 1348 fp->f_count++; 1349 fp->f_cred = crhold(td->td_ucred); 1350 fp->f_ops = &badfileops; 1351 fp->f_data = NULL; 1352 fp->f_vnode = NULL; 1353 FILEDESC_LOCK(p->p_fd); 1354 if ((fq = p->p_fd->fd_ofiles[0])) { 1355 LIST_INSERT_AFTER(fq, fp, f_list); 1356 } else { 1357 LIST_INSERT_HEAD(&filehead, fp, f_list); 1358 } 1359 sx_xunlock(&filelist_lock); 1360 if ((error = fdalloc(td, 0, &i))) { 1361 FILEDESC_UNLOCK(p->p_fd); 1362 fdrop(fp, td); 1363 if (resultfp) 1364 fdrop(fp, td); 1365 return (error); 1366 } 1367 p->p_fd->fd_ofiles[i] = fp; 1368 FILEDESC_UNLOCK(p->p_fd); 1369 if (resultfp) 1370 *resultfp = fp; 1371 if (resultfd) 1372 *resultfd = i; 1373 return (0); 1374 } 1375 1376 /* 1377 * Build a new filedesc structure from another. 1378 * Copy the current, root, and jail root vnode references. 1379 */ 1380 struct filedesc * 1381 fdinit(struct filedesc *fdp) 1382 { 1383 struct filedesc0 *newfdp; 1384 1385 newfdp = malloc(sizeof *newfdp, M_FILEDESC, M_WAITOK | M_ZERO); 1386 mtx_init(&newfdp->fd_fd.fd_mtx, FILEDESC_LOCK_DESC, NULL, MTX_DEF); 1387 if (fdp != NULL) { 1388 FILEDESC_LOCK(fdp); 1389 newfdp->fd_fd.fd_cdir = fdp->fd_cdir; 1390 if (newfdp->fd_fd.fd_cdir) 1391 VREF(newfdp->fd_fd.fd_cdir); 1392 newfdp->fd_fd.fd_rdir = fdp->fd_rdir; 1393 if (newfdp->fd_fd.fd_rdir) 1394 VREF(newfdp->fd_fd.fd_rdir); 1395 newfdp->fd_fd.fd_jdir = fdp->fd_jdir; 1396 if (newfdp->fd_fd.fd_jdir) 1397 VREF(newfdp->fd_fd.fd_jdir); 1398 FILEDESC_UNLOCK(fdp); 1399 } 1400 1401 /* Create the file descriptor table. */ 1402 newfdp->fd_fd.fd_refcnt = 1; 1403 newfdp->fd_fd.fd_holdcnt = 1; 1404 newfdp->fd_fd.fd_cmask = CMASK; 1405 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; 1406 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; 1407 newfdp->fd_fd.fd_nfiles = NDFILE; 1408 newfdp->fd_fd.fd_map = newfdp->fd_dmap; 1409 newfdp->fd_fd.fd_lastfile = -1; 1410 return (&newfdp->fd_fd); 1411 } 1412 1413 static struct filedesc * 1414 fdhold(struct proc *p) 1415 { 1416 struct filedesc *fdp; 1417 1418 mtx_lock(&fdesc_mtx); 1419 fdp = p->p_fd; 1420 if (fdp != NULL) 1421 fdp->fd_holdcnt++; 1422 mtx_unlock(&fdesc_mtx); 1423 return (fdp); 1424 } 1425 1426 static void 1427 fddrop(struct filedesc *fdp) 1428 { 1429 int i; 1430 1431 mtx_lock(&fdesc_mtx); 1432 i = --fdp->fd_holdcnt; 1433 mtx_unlock(&fdesc_mtx); 1434 if (i > 0) 1435 return; 1436 1437 mtx_destroy(&fdp->fd_mtx); 1438 FREE(fdp, M_FILEDESC); 1439 } 1440 1441 /* 1442 * Share a filedesc structure. 1443 */ 1444 struct filedesc * 1445 fdshare(struct filedesc *fdp) 1446 { 1447 FILEDESC_LOCK_FAST(fdp); 1448 fdp->fd_refcnt++; 1449 FILEDESC_UNLOCK_FAST(fdp); 1450 return (fdp); 1451 } 1452 1453 /* 1454 * Unshare a filedesc structure, if necessary by making a copy 1455 */ 1456 void 1457 fdunshare(struct proc *p, struct thread *td) 1458 { 1459 1460 FILEDESC_LOCK_FAST(p->p_fd); 1461 if (p->p_fd->fd_refcnt > 1) { 1462 struct filedesc *tmp; 1463 1464 FILEDESC_UNLOCK_FAST(p->p_fd); 1465 tmp = fdcopy(p->p_fd); 1466 fdfree(td); 1467 p->p_fd = tmp; 1468 } else 1469 FILEDESC_UNLOCK_FAST(p->p_fd); 1470 } 1471 1472 /* 1473 * Copy a filedesc structure. 1474 * A NULL pointer in returns a NULL reference, this is to ease callers, 1475 * not catch errors. 1476 */ 1477 struct filedesc * 1478 fdcopy(struct filedesc *fdp) 1479 { 1480 struct filedesc *newfdp; 1481 int i; 1482 1483 /* Certain daemons might not have file descriptors. */ 1484 if (fdp == NULL) 1485 return (NULL); 1486 1487 newfdp = fdinit(fdp); 1488 FILEDESC_LOCK_FAST(fdp); 1489 while (fdp->fd_lastfile >= newfdp->fd_nfiles) { 1490 FILEDESC_UNLOCK_FAST(fdp); 1491 FILEDESC_LOCK(newfdp); 1492 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1493 FILEDESC_UNLOCK(newfdp); 1494 FILEDESC_LOCK_FAST(fdp); 1495 } 1496 /* copy everything except kqueue descriptors */ 1497 newfdp->fd_freefile = -1; 1498 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1499 if (fdisused(fdp, i) && 1500 fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE) { 1501 newfdp->fd_ofiles[i] = fdp->fd_ofiles[i]; 1502 newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i]; 1503 fhold(newfdp->fd_ofiles[i]); 1504 newfdp->fd_lastfile = i; 1505 } else { 1506 if (newfdp->fd_freefile == -1) 1507 newfdp->fd_freefile = i; 1508 } 1509 } 1510 FILEDESC_UNLOCK_FAST(fdp); 1511 FILEDESC_LOCK(newfdp); 1512 for (i = 0; i <= newfdp->fd_lastfile; ++i) 1513 if (newfdp->fd_ofiles[i] != NULL) 1514 fdused(newfdp, i); 1515 FILEDESC_UNLOCK(newfdp); 1516 FILEDESC_LOCK_FAST(fdp); 1517 if (newfdp->fd_freefile == -1) 1518 newfdp->fd_freefile = i; 1519 newfdp->fd_cmask = fdp->fd_cmask; 1520 FILEDESC_UNLOCK_FAST(fdp); 1521 return (newfdp); 1522 } 1523 1524 /* 1525 * Release a filedesc structure. 1526 */ 1527 void 1528 fdfree(struct thread *td) 1529 { 1530 struct filedesc *fdp; 1531 struct file **fpp; 1532 int i, locked; 1533 struct filedesc_to_leader *fdtol; 1534 struct file *fp; 1535 struct vnode *cdir, *jdir, *rdir, *vp; 1536 struct flock lf; 1537 1538 /* Certain daemons might not have file descriptors. */ 1539 fdp = td->td_proc->p_fd; 1540 if (fdp == NULL) 1541 return; 1542 1543 /* Check for special need to clear POSIX style locks */ 1544 fdtol = td->td_proc->p_fdtol; 1545 if (fdtol != NULL) { 1546 FILEDESC_LOCK(fdp); 1547 KASSERT(fdtol->fdl_refcount > 0, 1548 ("filedesc_to_refcount botch: fdl_refcount=%d", 1549 fdtol->fdl_refcount)); 1550 if (fdtol->fdl_refcount == 1 && 1551 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1552 for (i = 0, fpp = fdp->fd_ofiles; 1553 i <= fdp->fd_lastfile; 1554 i++, fpp++) { 1555 if (*fpp == NULL || 1556 (*fpp)->f_type != DTYPE_VNODE) 1557 continue; 1558 fp = *fpp; 1559 fhold(fp); 1560 FILEDESC_UNLOCK(fdp); 1561 lf.l_whence = SEEK_SET; 1562 lf.l_start = 0; 1563 lf.l_len = 0; 1564 lf.l_type = F_UNLCK; 1565 vp = fp->f_vnode; 1566 locked = VFS_LOCK_GIANT(vp->v_mount); 1567 (void) VOP_ADVLOCK(vp, 1568 (caddr_t)td->td_proc-> 1569 p_leader, 1570 F_UNLCK, 1571 &lf, 1572 F_POSIX); 1573 VFS_UNLOCK_GIANT(locked); 1574 FILEDESC_LOCK(fdp); 1575 fdrop(fp, td); 1576 fpp = fdp->fd_ofiles + i; 1577 } 1578 } 1579 retry: 1580 if (fdtol->fdl_refcount == 1) { 1581 if (fdp->fd_holdleaderscount > 0 && 1582 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1583 /* 1584 * close() or do_dup() has cleared a reference 1585 * in a shared file descriptor table. 1586 */ 1587 fdp->fd_holdleaderswakeup = 1; 1588 msleep(&fdp->fd_holdleaderscount, &fdp->fd_mtx, 1589 PLOCK, "fdlhold", 0); 1590 goto retry; 1591 } 1592 if (fdtol->fdl_holdcount > 0) { 1593 /* 1594 * Ensure that fdtol->fdl_leader 1595 * remains valid in closef(). 1596 */ 1597 fdtol->fdl_wakeup = 1; 1598 msleep(fdtol, &fdp->fd_mtx, 1599 PLOCK, "fdlhold", 0); 1600 goto retry; 1601 } 1602 } 1603 fdtol->fdl_refcount--; 1604 if (fdtol->fdl_refcount == 0 && 1605 fdtol->fdl_holdcount == 0) { 1606 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1607 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1608 } else 1609 fdtol = NULL; 1610 td->td_proc->p_fdtol = NULL; 1611 FILEDESC_UNLOCK(fdp); 1612 if (fdtol != NULL) 1613 FREE(fdtol, M_FILEDESC_TO_LEADER); 1614 } 1615 FILEDESC_LOCK_FAST(fdp); 1616 i = --fdp->fd_refcnt; 1617 FILEDESC_UNLOCK_FAST(fdp); 1618 if (i > 0) 1619 return; 1620 /* 1621 * We are the last reference to the structure, so we can 1622 * safely assume it will not change out from under us. 1623 */ 1624 fpp = fdp->fd_ofiles; 1625 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) { 1626 if (*fpp) 1627 (void) closef(*fpp, td); 1628 } 1629 FILEDESC_LOCK(fdp); 1630 1631 /* XXX This should happen earlier. */ 1632 mtx_lock(&fdesc_mtx); 1633 td->td_proc->p_fd = NULL; 1634 mtx_unlock(&fdesc_mtx); 1635 1636 if (fdp->fd_nfiles > NDFILE) 1637 FREE(fdp->fd_ofiles, M_FILEDESC); 1638 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE)) 1639 FREE(fdp->fd_map, M_FILEDESC); 1640 1641 fdp->fd_nfiles = 0; 1642 1643 cdir = fdp->fd_cdir; 1644 fdp->fd_cdir = NULL; 1645 rdir = fdp->fd_rdir; 1646 fdp->fd_rdir = NULL; 1647 jdir = fdp->fd_jdir; 1648 fdp->fd_jdir = NULL; 1649 FILEDESC_UNLOCK(fdp); 1650 1651 if (cdir) { 1652 locked = VFS_LOCK_GIANT(cdir->v_mount); 1653 vrele(cdir); 1654 VFS_UNLOCK_GIANT(locked); 1655 } 1656 if (rdir) { 1657 locked = VFS_LOCK_GIANT(rdir->v_mount); 1658 vrele(rdir); 1659 VFS_UNLOCK_GIANT(locked); 1660 } 1661 if (jdir) { 1662 locked = VFS_LOCK_GIANT(jdir->v_mount); 1663 vrele(jdir); 1664 VFS_UNLOCK_GIANT(locked); 1665 } 1666 1667 fddrop(fdp); 1668 } 1669 1670 /* 1671 * For setugid programs, we don't want to people to use that setugidness 1672 * to generate error messages which write to a file which otherwise would 1673 * otherwise be off-limits to the process. We check for filesystems where 1674 * the vnode can change out from under us after execve (like [lin]procfs). 1675 * 1676 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 1677 * sufficient. We also don't check for setugidness since we know we are. 1678 */ 1679 static int 1680 is_unsafe(struct file *fp) 1681 { 1682 if (fp->f_type == DTYPE_VNODE) { 1683 struct vnode *vp = fp->f_vnode; 1684 1685 if ((vp->v_vflag & VV_PROCDEP) != 0) 1686 return (1); 1687 } 1688 return (0); 1689 } 1690 1691 /* 1692 * Make this setguid thing safe, if at all possible. 1693 */ 1694 void 1695 setugidsafety(struct thread *td) 1696 { 1697 struct filedesc *fdp; 1698 int i; 1699 1700 /* Certain daemons might not have file descriptors. */ 1701 fdp = td->td_proc->p_fd; 1702 if (fdp == NULL) 1703 return; 1704 1705 /* 1706 * Note: fdp->fd_ofiles may be reallocated out from under us while 1707 * we are blocked in a close. Be careful! 1708 */ 1709 FILEDESC_LOCK(fdp); 1710 for (i = 0; i <= fdp->fd_lastfile; i++) { 1711 if (i > 2) 1712 break; 1713 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) { 1714 struct file *fp; 1715 1716 knote_fdclose(td, i); 1717 /* 1718 * NULL-out descriptor prior to close to avoid 1719 * a race while close blocks. 1720 */ 1721 fp = fdp->fd_ofiles[i]; 1722 fdp->fd_ofiles[i] = NULL; 1723 fdp->fd_ofileflags[i] = 0; 1724 fdunused(fdp, i); 1725 FILEDESC_UNLOCK(fdp); 1726 (void) closef(fp, td); 1727 FILEDESC_LOCK(fdp); 1728 } 1729 } 1730 FILEDESC_UNLOCK(fdp); 1731 } 1732 1733 void 1734 fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td) 1735 { 1736 1737 FILEDESC_LOCK(fdp); 1738 if (fdp->fd_ofiles[idx] == fp) { 1739 fdp->fd_ofiles[idx] = NULL; 1740 fdunused(fdp, idx); 1741 FILEDESC_UNLOCK(fdp); 1742 fdrop(fp, td); 1743 } else { 1744 FILEDESC_UNLOCK(fdp); 1745 } 1746 } 1747 1748 /* 1749 * Close any files on exec? 1750 */ 1751 void 1752 fdcloseexec(struct thread *td) 1753 { 1754 struct filedesc *fdp; 1755 int i; 1756 1757 /* Certain daemons might not have file descriptors. */ 1758 fdp = td->td_proc->p_fd; 1759 if (fdp == NULL) 1760 return; 1761 1762 FILEDESC_LOCK(fdp); 1763 1764 /* 1765 * We cannot cache fd_ofiles or fd_ofileflags since operations 1766 * may block and rip them out from under us. 1767 */ 1768 for (i = 0; i <= fdp->fd_lastfile; i++) { 1769 if (fdp->fd_ofiles[i] != NULL && 1770 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) { 1771 struct file *fp; 1772 1773 knote_fdclose(td, i); 1774 /* 1775 * NULL-out descriptor prior to close to avoid 1776 * a race while close blocks. 1777 */ 1778 fp = fdp->fd_ofiles[i]; 1779 fdp->fd_ofiles[i] = NULL; 1780 fdp->fd_ofileflags[i] = 0; 1781 fdunused(fdp, i); 1782 FILEDESC_UNLOCK(fdp); 1783 (void) closef(fp, td); 1784 FILEDESC_LOCK(fdp); 1785 } 1786 } 1787 FILEDESC_UNLOCK(fdp); 1788 } 1789 1790 /* 1791 * It is unsafe for set[ug]id processes to be started with file 1792 * descriptors 0..2 closed, as these descriptors are given implicit 1793 * significance in the Standard C library. fdcheckstd() will create a 1794 * descriptor referencing /dev/null for each of stdin, stdout, and 1795 * stderr that is not already open. 1796 */ 1797 int 1798 fdcheckstd(struct thread *td) 1799 { 1800 struct nameidata nd; 1801 struct filedesc *fdp; 1802 struct file *fp; 1803 register_t retval; 1804 int fd, i, error, flags, devnull; 1805 1806 fdp = td->td_proc->p_fd; 1807 if (fdp == NULL) 1808 return (0); 1809 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 1810 devnull = -1; 1811 error = 0; 1812 for (i = 0; i < 3; i++) { 1813 if (fdp->fd_ofiles[i] != NULL) 1814 continue; 1815 if (devnull < 0) { 1816 int vfslocked; 1817 error = falloc(td, &fp, &fd); 1818 if (error != 0) 1819 break; 1820 /* Note extra ref on `fp' held for us by falloc(). */ 1821 KASSERT(fd == i, ("oof, we didn't get our fd")); 1822 NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, 1823 "/dev/null", td); 1824 flags = FREAD | FWRITE; 1825 error = vn_open(&nd, &flags, 0, fd); 1826 if (error != 0) { 1827 /* 1828 * Someone may have closed the entry in the 1829 * file descriptor table, so check it hasn't 1830 * changed before dropping the reference count. 1831 */ 1832 FILEDESC_LOCK(fdp); 1833 KASSERT(fdp->fd_ofiles[fd] == fp, 1834 ("table not shared, how did it change?")); 1835 fdp->fd_ofiles[fd] = NULL; 1836 fdunused(fdp, fd); 1837 FILEDESC_UNLOCK(fdp); 1838 fdrop(fp, td); 1839 fdrop(fp, td); 1840 break; 1841 } 1842 vfslocked = NDHASGIANT(&nd); 1843 NDFREE(&nd, NDF_ONLY_PNBUF); 1844 fp->f_flag = flags; 1845 fp->f_vnode = nd.ni_vp; 1846 if (fp->f_data == NULL) 1847 fp->f_data = nd.ni_vp; 1848 if (fp->f_ops == &badfileops) 1849 fp->f_ops = &vnops; 1850 fp->f_type = DTYPE_VNODE; 1851 VOP_UNLOCK(nd.ni_vp, 0, td); 1852 VFS_UNLOCK_GIANT(vfslocked); 1853 devnull = fd; 1854 fdrop(fp, td); 1855 } else { 1856 error = do_dup(td, DUP_FIXED, devnull, i, &retval); 1857 if (error != 0) 1858 break; 1859 } 1860 } 1861 return (error); 1862 } 1863 1864 /* 1865 * Internal form of close. 1866 * Decrement reference count on file structure. 1867 * Note: td may be NULL when closing a file that was being passed in a 1868 * message. 1869 * 1870 * XXXRW: Giant is not required for the caller, but often will be held; this 1871 * makes it moderately likely the Giant will be recursed in the VFS case. 1872 */ 1873 int 1874 closef(struct file *fp, struct thread *td) 1875 { 1876 struct vnode *vp; 1877 struct flock lf; 1878 struct filedesc_to_leader *fdtol; 1879 struct filedesc *fdp; 1880 1881 /* 1882 * POSIX record locking dictates that any close releases ALL 1883 * locks owned by this process. This is handled by setting 1884 * a flag in the unlock to free ONLY locks obeying POSIX 1885 * semantics, and not to free BSD-style file locks. 1886 * If the descriptor was in a message, POSIX-style locks 1887 * aren't passed with the descriptor, and the thread pointer 1888 * will be NULL. Callers should be careful only to pass a 1889 * NULL thread pointer when there really is no owning 1890 * context that might have locks, or the locks will be 1891 * leaked. 1892 */ 1893 if (fp->f_type == DTYPE_VNODE && td != NULL) { 1894 int vfslocked; 1895 1896 vp = fp->f_vnode; 1897 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 1898 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1899 lf.l_whence = SEEK_SET; 1900 lf.l_start = 0; 1901 lf.l_len = 0; 1902 lf.l_type = F_UNLCK; 1903 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader, 1904 F_UNLCK, &lf, F_POSIX); 1905 } 1906 fdtol = td->td_proc->p_fdtol; 1907 if (fdtol != NULL) { 1908 /* 1909 * Handle special case where file descriptor table 1910 * is shared between multiple process leaders. 1911 */ 1912 fdp = td->td_proc->p_fd; 1913 FILEDESC_LOCK(fdp); 1914 for (fdtol = fdtol->fdl_next; 1915 fdtol != td->td_proc->p_fdtol; 1916 fdtol = fdtol->fdl_next) { 1917 if ((fdtol->fdl_leader->p_flag & 1918 P_ADVLOCK) == 0) 1919 continue; 1920 fdtol->fdl_holdcount++; 1921 FILEDESC_UNLOCK(fdp); 1922 lf.l_whence = SEEK_SET; 1923 lf.l_start = 0; 1924 lf.l_len = 0; 1925 lf.l_type = F_UNLCK; 1926 vp = fp->f_vnode; 1927 (void) VOP_ADVLOCK(vp, 1928 (caddr_t)fdtol->fdl_leader, 1929 F_UNLCK, &lf, F_POSIX); 1930 FILEDESC_LOCK(fdp); 1931 fdtol->fdl_holdcount--; 1932 if (fdtol->fdl_holdcount == 0 && 1933 fdtol->fdl_wakeup != 0) { 1934 fdtol->fdl_wakeup = 0; 1935 wakeup(fdtol); 1936 } 1937 } 1938 FILEDESC_UNLOCK(fdp); 1939 } 1940 VFS_UNLOCK_GIANT(vfslocked); 1941 } 1942 return (fdrop(fp, td)); 1943 } 1944 1945 /* 1946 * Extract the file pointer associated with the specified descriptor for 1947 * the current user process. 1948 * 1949 * If the descriptor doesn't exist, EBADF is returned. 1950 * 1951 * If the descriptor exists but doesn't match 'flags' then 1952 * return EBADF for read attempts and EINVAL for write attempts. 1953 * 1954 * If 'hold' is set (non-zero) the file's refcount will be bumped on return. 1955 * It should be dropped with fdrop(). 1956 * If it is not set, then the refcount will not be bumped however the 1957 * thread's filedesc struct will be returned locked (for fgetsock). 1958 * 1959 * If an error occured the non-zero error is returned and *fpp is set to NULL. 1960 * Otherwise *fpp is set and zero is returned. 1961 */ 1962 static __inline int 1963 _fget(struct thread *td, int fd, struct file **fpp, int flags, int hold) 1964 { 1965 struct filedesc *fdp; 1966 struct file *fp; 1967 1968 *fpp = NULL; 1969 if (td == NULL || (fdp = td->td_proc->p_fd) == NULL) 1970 return (EBADF); 1971 FILEDESC_LOCK(fdp); 1972 if ((fp = fget_locked(fdp, fd)) == NULL || fp->f_ops == &badfileops) { 1973 FILEDESC_UNLOCK(fdp); 1974 return (EBADF); 1975 } 1976 1977 /* 1978 * Note: FREAD failure returns EBADF to maintain backwards 1979 * compatibility with what routines returned before. 1980 * 1981 * Only one flag, or 0, may be specified. 1982 */ 1983 if (flags == FREAD && (fp->f_flag & FREAD) == 0) { 1984 FILEDESC_UNLOCK(fdp); 1985 return (EBADF); 1986 } 1987 if (flags == FWRITE && (fp->f_flag & FWRITE) == 0) { 1988 FILEDESC_UNLOCK(fdp); 1989 return (EINVAL); 1990 } 1991 if (hold) { 1992 fhold(fp); 1993 FILEDESC_UNLOCK(fdp); 1994 } 1995 *fpp = fp; 1996 return (0); 1997 } 1998 1999 int 2000 fget(struct thread *td, int fd, struct file **fpp) 2001 { 2002 2003 return(_fget(td, fd, fpp, 0, 1)); 2004 } 2005 2006 int 2007 fget_read(struct thread *td, int fd, struct file **fpp) 2008 { 2009 2010 return(_fget(td, fd, fpp, FREAD, 1)); 2011 } 2012 2013 int 2014 fget_write(struct thread *td, int fd, struct file **fpp) 2015 { 2016 2017 return(_fget(td, fd, fpp, FWRITE, 1)); 2018 } 2019 2020 /* 2021 * Like fget() but loads the underlying vnode, or returns an error if 2022 * the descriptor does not represent a vnode. Note that pipes use vnodes 2023 * but never have VM objects. The returned vnode will be vref()d. 2024 * 2025 * XXX: what about the unused flags ? 2026 */ 2027 static __inline int 2028 _fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags) 2029 { 2030 struct file *fp; 2031 int error; 2032 2033 *vpp = NULL; 2034 if ((error = _fget(td, fd, &fp, flags, 0)) != 0) 2035 return (error); 2036 if (fp->f_vnode == NULL) { 2037 error = EINVAL; 2038 } else { 2039 *vpp = fp->f_vnode; 2040 vref(*vpp); 2041 } 2042 FILEDESC_UNLOCK(td->td_proc->p_fd); 2043 return (error); 2044 } 2045 2046 int 2047 fgetvp(struct thread *td, int fd, struct vnode **vpp) 2048 { 2049 2050 return (_fgetvp(td, fd, vpp, 0)); 2051 } 2052 2053 int 2054 fgetvp_read(struct thread *td, int fd, struct vnode **vpp) 2055 { 2056 2057 return (_fgetvp(td, fd, vpp, FREAD)); 2058 } 2059 2060 #ifdef notyet 2061 int 2062 fgetvp_write(struct thread *td, int fd, struct vnode **vpp) 2063 { 2064 2065 return (_fgetvp(td, fd, vpp, FWRITE)); 2066 } 2067 #endif 2068 2069 /* 2070 * Like fget() but loads the underlying socket, or returns an error if 2071 * the descriptor does not represent a socket. 2072 * 2073 * We bump the ref count on the returned socket. XXX Also obtain the SX 2074 * lock in the future. 2075 */ 2076 int 2077 fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp) 2078 { 2079 struct file *fp; 2080 int error; 2081 2082 NET_ASSERT_GIANT(); 2083 2084 *spp = NULL; 2085 if (fflagp != NULL) 2086 *fflagp = 0; 2087 if ((error = _fget(td, fd, &fp, 0, 0)) != 0) 2088 return (error); 2089 if (fp->f_type != DTYPE_SOCKET) { 2090 error = ENOTSOCK; 2091 } else { 2092 *spp = fp->f_data; 2093 if (fflagp) 2094 *fflagp = fp->f_flag; 2095 SOCK_LOCK(*spp); 2096 soref(*spp); 2097 SOCK_UNLOCK(*spp); 2098 } 2099 FILEDESC_UNLOCK(td->td_proc->p_fd); 2100 return (error); 2101 } 2102 2103 /* 2104 * Drop the reference count on the socket and XXX release the SX lock in 2105 * the future. The last reference closes the socket. 2106 */ 2107 void 2108 fputsock(struct socket *so) 2109 { 2110 2111 NET_ASSERT_GIANT(); 2112 ACCEPT_LOCK(); 2113 SOCK_LOCK(so); 2114 sorele(so); 2115 } 2116 2117 int 2118 fdrop(struct file *fp, struct thread *td) 2119 { 2120 2121 FILE_LOCK(fp); 2122 return (fdrop_locked(fp, td)); 2123 } 2124 2125 /* 2126 * Drop reference on struct file passed in, may call closef if the 2127 * reference hits zero. 2128 * Expects struct file locked, and will unlock it. 2129 */ 2130 static int 2131 fdrop_locked(struct file *fp, struct thread *td) 2132 { 2133 int error; 2134 2135 FILE_LOCK_ASSERT(fp, MA_OWNED); 2136 2137 if (--fp->f_count > 0) { 2138 FILE_UNLOCK(fp); 2139 return (0); 2140 } 2141 /* We have the last ref so we can proceed without the file lock. */ 2142 FILE_UNLOCK(fp); 2143 if (fp->f_count < 0) 2144 panic("fdrop: count < 0"); 2145 if (fp->f_ops != &badfileops) 2146 error = fo_close(fp, td); 2147 else 2148 error = 0; 2149 2150 sx_xlock(&filelist_lock); 2151 LIST_REMOVE(fp, f_list); 2152 openfiles--; 2153 sx_xunlock(&filelist_lock); 2154 crfree(fp->f_cred); 2155 uma_zfree(file_zone, fp); 2156 2157 return (error); 2158 } 2159 2160 /* 2161 * Apply an advisory lock on a file descriptor. 2162 * 2163 * Just attempt to get a record lock of the requested type on 2164 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2165 */ 2166 #ifndef _SYS_SYSPROTO_H_ 2167 struct flock_args { 2168 int fd; 2169 int how; 2170 }; 2171 #endif 2172 /* 2173 * MPSAFE 2174 */ 2175 /* ARGSUSED */ 2176 int 2177 flock(struct thread *td, struct flock_args *uap) 2178 { 2179 struct file *fp; 2180 struct vnode *vp; 2181 struct flock lf; 2182 int error; 2183 2184 if ((error = fget(td, uap->fd, &fp)) != 0) 2185 return (error); 2186 if (fp->f_type != DTYPE_VNODE) { 2187 fdrop(fp, td); 2188 return (EOPNOTSUPP); 2189 } 2190 2191 mtx_lock(&Giant); 2192 vp = fp->f_vnode; 2193 lf.l_whence = SEEK_SET; 2194 lf.l_start = 0; 2195 lf.l_len = 0; 2196 if (uap->how & LOCK_UN) { 2197 lf.l_type = F_UNLCK; 2198 FILE_LOCK(fp); 2199 fp->f_flag &= ~FHASLOCK; 2200 FILE_UNLOCK(fp); 2201 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 2202 goto done2; 2203 } 2204 if (uap->how & LOCK_EX) 2205 lf.l_type = F_WRLCK; 2206 else if (uap->how & LOCK_SH) 2207 lf.l_type = F_RDLCK; 2208 else { 2209 error = EBADF; 2210 goto done2; 2211 } 2212 FILE_LOCK(fp); 2213 fp->f_flag |= FHASLOCK; 2214 FILE_UNLOCK(fp); 2215 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 2216 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT); 2217 done2: 2218 fdrop(fp, td); 2219 mtx_unlock(&Giant); 2220 return (error); 2221 } 2222 /* 2223 * Duplicate the specified descriptor to a free descriptor. 2224 */ 2225 int 2226 dupfdopen(struct thread *td, struct filedesc *fdp, int indx, int dfd, int mode, int error) 2227 { 2228 struct file *wfp; 2229 struct file *fp; 2230 2231 /* 2232 * If the to-be-dup'd fd number is greater than the allowed number 2233 * of file descriptors, or the fd to be dup'd has already been 2234 * closed, then reject. 2235 */ 2236 FILEDESC_LOCK(fdp); 2237 if (dfd < 0 || dfd >= fdp->fd_nfiles || 2238 (wfp = fdp->fd_ofiles[dfd]) == NULL) { 2239 FILEDESC_UNLOCK(fdp); 2240 return (EBADF); 2241 } 2242 2243 /* 2244 * There are two cases of interest here. 2245 * 2246 * For ENODEV simply dup (dfd) to file descriptor 2247 * (indx) and return. 2248 * 2249 * For ENXIO steal away the file structure from (dfd) and 2250 * store it in (indx). (dfd) is effectively closed by 2251 * this operation. 2252 * 2253 * Any other error code is just returned. 2254 */ 2255 switch (error) { 2256 case ENODEV: 2257 /* 2258 * Check that the mode the file is being opened for is a 2259 * subset of the mode of the existing descriptor. 2260 */ 2261 FILE_LOCK(wfp); 2262 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2263 FILE_UNLOCK(wfp); 2264 FILEDESC_UNLOCK(fdp); 2265 return (EACCES); 2266 } 2267 fp = fdp->fd_ofiles[indx]; 2268 fdp->fd_ofiles[indx] = wfp; 2269 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2270 if (fp == NULL) 2271 fdused(fdp, indx); 2272 fhold_locked(wfp); 2273 FILE_UNLOCK(wfp); 2274 FILEDESC_UNLOCK(fdp); 2275 if (fp != NULL) { 2276 /* 2277 * We now own the reference to fp that the ofiles[] 2278 * array used to own. Release it. 2279 */ 2280 FILE_LOCK(fp); 2281 fdrop_locked(fp, td); 2282 } 2283 return (0); 2284 2285 case ENXIO: 2286 /* 2287 * Steal away the file pointer from dfd and stuff it into indx. 2288 */ 2289 fp = fdp->fd_ofiles[indx]; 2290 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd]; 2291 fdp->fd_ofiles[dfd] = NULL; 2292 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2293 fdp->fd_ofileflags[dfd] = 0; 2294 fdunused(fdp, dfd); 2295 if (fp == NULL) 2296 fdused(fdp, indx); 2297 if (fp != NULL) 2298 FILE_LOCK(fp); 2299 2300 /* 2301 * We now own the reference to fp that the ofiles[] array 2302 * used to own. Release it. 2303 */ 2304 if (fp != NULL) 2305 fdrop_locked(fp, td); 2306 2307 FILEDESC_UNLOCK(fdp); 2308 2309 return (0); 2310 2311 default: 2312 FILEDESC_UNLOCK(fdp); 2313 return (error); 2314 } 2315 /* NOTREACHED */ 2316 } 2317 2318 /* 2319 * Scan all active processes to see if any of them have a current 2320 * or root directory of `olddp'. If so, replace them with the new 2321 * mount point. 2322 */ 2323 void 2324 mountcheckdirs(struct vnode *olddp, struct vnode *newdp) 2325 { 2326 struct filedesc *fdp; 2327 struct proc *p; 2328 int nrele; 2329 2330 if (vrefcnt(olddp) == 1) 2331 return; 2332 sx_slock(&allproc_lock); 2333 LIST_FOREACH(p, &allproc, p_list) { 2334 fdp = fdhold(p); 2335 if (fdp == NULL) 2336 continue; 2337 nrele = 0; 2338 FILEDESC_LOCK_FAST(fdp); 2339 if (fdp->fd_cdir == olddp) { 2340 vref(newdp); 2341 fdp->fd_cdir = newdp; 2342 nrele++; 2343 } 2344 if (fdp->fd_rdir == olddp) { 2345 vref(newdp); 2346 fdp->fd_rdir = newdp; 2347 nrele++; 2348 } 2349 FILEDESC_UNLOCK_FAST(fdp); 2350 fddrop(fdp); 2351 while (nrele--) 2352 vrele(olddp); 2353 } 2354 sx_sunlock(&allproc_lock); 2355 if (rootvnode == olddp) { 2356 vrele(rootvnode); 2357 vref(newdp); 2358 rootvnode = newdp; 2359 } 2360 } 2361 2362 struct filedesc_to_leader * 2363 filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader) 2364 { 2365 struct filedesc_to_leader *fdtol; 2366 2367 MALLOC(fdtol, struct filedesc_to_leader *, 2368 sizeof(struct filedesc_to_leader), 2369 M_FILEDESC_TO_LEADER, 2370 M_WAITOK); 2371 fdtol->fdl_refcount = 1; 2372 fdtol->fdl_holdcount = 0; 2373 fdtol->fdl_wakeup = 0; 2374 fdtol->fdl_leader = leader; 2375 if (old != NULL) { 2376 FILEDESC_LOCK(fdp); 2377 fdtol->fdl_next = old->fdl_next; 2378 fdtol->fdl_prev = old; 2379 old->fdl_next = fdtol; 2380 fdtol->fdl_next->fdl_prev = fdtol; 2381 FILEDESC_UNLOCK(fdp); 2382 } else { 2383 fdtol->fdl_next = fdtol; 2384 fdtol->fdl_prev = fdtol; 2385 } 2386 return (fdtol); 2387 } 2388 2389 /* 2390 * Get file structures. 2391 */ 2392 static int 2393 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2394 { 2395 struct xfile xf; 2396 struct filedesc *fdp; 2397 struct file *fp; 2398 struct proc *p; 2399 int error, n; 2400 2401 /* 2402 * Note: because the number of file descriptors is calculated 2403 * in different ways for sizing vs returning the data, 2404 * there is information leakage from the first loop. However, 2405 * it is of a similar order of magnitude to the leakage from 2406 * global system statistics such as kern.openfiles. 2407 */ 2408 error = sysctl_wire_old_buffer(req, 0); 2409 if (error != 0) 2410 return (error); 2411 if (req->oldptr == NULL) { 2412 n = 16; /* A slight overestimate. */ 2413 sx_slock(&filelist_lock); 2414 LIST_FOREACH(fp, &filehead, f_list) { 2415 /* 2416 * We should grab the lock, but this is an 2417 * estimate, so does it really matter? 2418 */ 2419 /* mtx_lock(fp->f_mtxp); */ 2420 n += fp->f_count; 2421 /* mtx_unlock(f->f_mtxp); */ 2422 } 2423 sx_sunlock(&filelist_lock); 2424 return (SYSCTL_OUT(req, 0, n * sizeof(xf))); 2425 } 2426 error = 0; 2427 bzero(&xf, sizeof(xf)); 2428 xf.xf_size = sizeof(xf); 2429 sx_slock(&allproc_lock); 2430 LIST_FOREACH(p, &allproc, p_list) { 2431 if (p->p_state == PRS_NEW) 2432 continue; 2433 PROC_LOCK(p); 2434 if (p_cansee(req->td, p) != 0) { 2435 PROC_UNLOCK(p); 2436 continue; 2437 } 2438 xf.xf_pid = p->p_pid; 2439 xf.xf_uid = p->p_ucred->cr_uid; 2440 PROC_UNLOCK(p); 2441 fdp = fdhold(p); 2442 if (fdp == NULL) 2443 continue; 2444 FILEDESC_LOCK_FAST(fdp); 2445 for (n = 0; fdp->fd_refcnt > 0 && n < fdp->fd_nfiles; ++n) { 2446 if ((fp = fdp->fd_ofiles[n]) == NULL) 2447 continue; 2448 xf.xf_fd = n; 2449 xf.xf_file = fp; 2450 xf.xf_data = fp->f_data; 2451 xf.xf_vnode = fp->f_vnode; 2452 xf.xf_type = fp->f_type; 2453 xf.xf_count = fp->f_count; 2454 xf.xf_msgcount = fp->f_msgcount; 2455 xf.xf_offset = fp->f_offset; 2456 xf.xf_flag = fp->f_flag; 2457 error = SYSCTL_OUT(req, &xf, sizeof(xf)); 2458 if (error) 2459 break; 2460 } 2461 FILEDESC_UNLOCK_FAST(fdp); 2462 fddrop(fdp); 2463 if (error) 2464 break; 2465 } 2466 sx_sunlock(&allproc_lock); 2467 return (error); 2468 } 2469 2470 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2471 0, 0, sysctl_kern_file, "S,xfile", "Entire file table"); 2472 2473 #ifdef DDB 2474 /* 2475 * For the purposes of debugging, generate a human-readable string for the 2476 * file type. 2477 */ 2478 static const char * 2479 file_type_to_name(short type) 2480 { 2481 2482 switch (type) { 2483 case 0: 2484 return ("zero"); 2485 case DTYPE_VNODE: 2486 return ("vnod"); 2487 case DTYPE_SOCKET: 2488 return ("sock"); 2489 case DTYPE_PIPE: 2490 return ("pipe"); 2491 case DTYPE_FIFO: 2492 return ("fifo"); 2493 case DTYPE_CRYPTO: 2494 return ("crpt"); 2495 default: 2496 return ("unkn"); 2497 } 2498 } 2499 2500 /* 2501 * For the purposes of debugging, identify a process (if any, perhaps one of 2502 * many) that references the passed file in its file descriptor array. Return 2503 * NULL if none. 2504 */ 2505 static struct proc * 2506 file_to_first_proc(struct file *fp) 2507 { 2508 struct filedesc *fdp; 2509 struct proc *p; 2510 int n; 2511 2512 LIST_FOREACH(p, &allproc, p_list) { 2513 if (p->p_state == PRS_NEW) 2514 continue; 2515 fdp = p->p_fd; 2516 if (fdp == NULL) 2517 continue; 2518 for (n = 0; n < fdp->fd_nfiles; n++) { 2519 if (fp == fdp->fd_ofiles[n]) 2520 return (p); 2521 } 2522 } 2523 return (NULL); 2524 } 2525 2526 DB_SHOW_COMMAND(files, db_show_files) 2527 { 2528 struct file *fp; 2529 struct proc *p; 2530 2531 db_printf("%8s %4s %8s %8s %4s %5s %6s %8s %5s %12s\n", "File", 2532 "Type", "Data", "Flag", "GCFl", "Count", "MCount", "Vnode", 2533 "FPID", "FCmd"); 2534 LIST_FOREACH(fp, &filehead, f_list) { 2535 p = file_to_first_proc(fp); 2536 db_printf("%8p %4s %8p %08x %04x %5d %6d %8p %5d %12s\n", fp, 2537 file_type_to_name(fp->f_type), fp->f_data, fp->f_flag, 2538 fp->f_gcflag, fp->f_count, fp->f_msgcount, fp->f_vnode, 2539 p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-"); 2540 } 2541 } 2542 #endif 2543 2544 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 2545 &maxfilesperproc, 0, "Maximum files allowed open per process"); 2546 2547 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 2548 &maxfiles, 0, "Maximum number of files"); 2549 2550 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 2551 &openfiles, 0, "System-wide number of open files"); 2552 2553 /* ARGSUSED*/ 2554 static void 2555 filelistinit(void *dummy) 2556 { 2557 2558 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL, 2559 NULL, NULL, UMA_ALIGN_PTR, 0); 2560 sx_init(&filelist_lock, "filelist lock"); 2561 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF); 2562 mtx_init(&fdesc_mtx, "fdesc", NULL, MTX_DEF); 2563 } 2564 SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL) 2565 2566 /*-------------------------------------------------------------------*/ 2567 2568 static int 2569 badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td) 2570 { 2571 2572 return (EBADF); 2573 } 2574 2575 static int 2576 badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, struct thread *td) 2577 { 2578 2579 return (EBADF); 2580 } 2581 2582 static int 2583 badfo_poll(struct file *fp, int events, struct ucred *active_cred, struct thread *td) 2584 { 2585 2586 return (0); 2587 } 2588 2589 static int 2590 badfo_kqfilter(struct file *fp, struct knote *kn) 2591 { 2592 2593 return (0); 2594 } 2595 2596 static int 2597 badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, struct thread *td) 2598 { 2599 2600 return (EBADF); 2601 } 2602 2603 static int 2604 badfo_close(struct file *fp, struct thread *td) 2605 { 2606 2607 return (EBADF); 2608 } 2609 2610 struct fileops badfileops = { 2611 .fo_read = badfo_readwrite, 2612 .fo_write = badfo_readwrite, 2613 .fo_ioctl = badfo_ioctl, 2614 .fo_poll = badfo_poll, 2615 .fo_kqfilter = badfo_kqfilter, 2616 .fo_stat = badfo_stat, 2617 .fo_close = badfo_close, 2618 }; 2619 2620 2621 /*-------------------------------------------------------------------*/ 2622 2623 /* 2624 * File Descriptor pseudo-device driver (/dev/fd/). 2625 * 2626 * Opening minor device N dup()s the file (if any) connected to file 2627 * descriptor N belonging to the calling process. Note that this driver 2628 * consists of only the ``open()'' routine, because all subsequent 2629 * references to this file will be direct to the other driver. 2630 * 2631 * XXX: we could give this one a cloning event handler if necessary. 2632 */ 2633 2634 /* ARGSUSED */ 2635 static int 2636 fdopen(struct cdev *dev, int mode, int type, struct thread *td) 2637 { 2638 2639 /* 2640 * XXX Kludge: set curthread->td_dupfd to contain the value of the 2641 * the file descriptor being sought for duplication. The error 2642 * return ensures that the vnode for this device will be released 2643 * by vn_open. Open will detect this special error and take the 2644 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 2645 * will simply report the error. 2646 */ 2647 td->td_dupfd = dev2unit(dev); 2648 return (ENODEV); 2649 } 2650 2651 static struct cdevsw fildesc_cdevsw = { 2652 .d_version = D_VERSION, 2653 .d_flags = D_NEEDGIANT, 2654 .d_open = fdopen, 2655 .d_name = "FD", 2656 }; 2657 2658 static void 2659 fildesc_drvinit(void *unused) 2660 { 2661 struct cdev *dev; 2662 2663 dev = make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "fd/0"); 2664 make_dev_alias(dev, "stdin"); 2665 dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1"); 2666 make_dev_alias(dev, "stdout"); 2667 dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2"); 2668 make_dev_alias(dev, "stderr"); 2669 } 2670 2671 SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL)
Cache object: 4ce9d8f514d05d99ce5d013f30cfe203
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