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/6.3/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 <security/audit/audit.h> 72 73 #include <vm/uma.h> 74 75 #include <ddb/ddb.h> 76 77 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 78 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 79 "file desc to leader structures"); 80 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 81 82 static uma_zone_t file_zone; 83 84 85 /* How to treat 'new' parameter when allocating a fd for do_dup(). */ 86 enum dup_type { DUP_VARIABLE, DUP_FIXED }; 87 88 static int do_dup(struct thread *td, enum dup_type type, int old, int new, 89 register_t *retval); 90 static int fd_first_free(struct filedesc *, int, int); 91 static int fd_last_used(struct filedesc *, int, int); 92 static void fdgrowtable(struct filedesc *, int); 93 static int fdrop_locked(struct file *fp, struct thread *td); 94 static void fdunused(struct filedesc *fdp, int fd); 95 static void fdused(struct filedesc *fdp, int fd); 96 97 /* 98 * A process is initially started out with NDFILE descriptors stored within 99 * this structure, selected to be enough for typical applications based on 100 * the historical limit of 20 open files (and the usage of descriptors by 101 * shells). If these descriptors are exhausted, a larger descriptor table 102 * may be allocated, up to a process' resource limit; the internal arrays 103 * are then unused. 104 */ 105 #define NDFILE 20 106 #define NDSLOTSIZE sizeof(NDSLOTTYPE) 107 #define NDENTRIES (NDSLOTSIZE * __CHAR_BIT) 108 #define NDSLOT(x) ((x) / NDENTRIES) 109 #define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES)) 110 #define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES) 111 112 /* 113 * Storage required per open file descriptor. 114 */ 115 #define OFILESIZE (sizeof(struct file *) + sizeof(char)) 116 117 /* 118 * Basic allocation of descriptors: 119 * one of the above, plus arrays for NDFILE descriptors. 120 */ 121 struct filedesc0 { 122 struct filedesc fd_fd; 123 /* 124 * These arrays are used when the number of open files is 125 * <= NDFILE, and are then pointed to by the pointers above. 126 */ 127 struct file *fd_dfiles[NDFILE]; 128 char fd_dfileflags[NDFILE]; 129 NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)]; 130 }; 131 132 /* 133 * Descriptor management. 134 */ 135 struct filelist filehead; /* head of list of open files */ 136 int openfiles; /* actual number of open files */ 137 struct sx filelist_lock; /* sx to protect filelist */ 138 struct mtx sigio_lock; /* mtx to protect pointers to sigio */ 139 140 /* A mutex to protect the association between a proc and filedesc. */ 141 static struct mtx fdesc_mtx; 142 143 /* 144 * Find the first zero bit in the given bitmap, starting at low and not 145 * exceeding size - 1. 146 */ 147 static int 148 fd_first_free(struct filedesc *fdp, int low, int size) 149 { 150 NDSLOTTYPE *map = fdp->fd_map; 151 NDSLOTTYPE mask; 152 int off, maxoff; 153 154 if (low >= size) 155 return (low); 156 157 off = NDSLOT(low); 158 if (low % NDENTRIES) { 159 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES))); 160 if ((mask &= ~map[off]) != 0UL) 161 return (off * NDENTRIES + ffsl(mask) - 1); 162 ++off; 163 } 164 for (maxoff = NDSLOTS(size); off < maxoff; ++off) 165 if (map[off] != ~0UL) 166 return (off * NDENTRIES + ffsl(~map[off]) - 1); 167 return (size); 168 } 169 170 /* 171 * Find the highest non-zero bit in the given bitmap, starting at low and 172 * not exceeding size - 1. 173 */ 174 static int 175 fd_last_used(struct filedesc *fdp, int low, int size) 176 { 177 NDSLOTTYPE *map = fdp->fd_map; 178 NDSLOTTYPE mask; 179 int off, minoff; 180 181 if (low >= size) 182 return (-1); 183 184 off = NDSLOT(size); 185 if (size % NDENTRIES) { 186 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES)); 187 if ((mask &= map[off]) != 0) 188 return (off * NDENTRIES + flsl(mask) - 1); 189 --off; 190 } 191 for (minoff = NDSLOT(low); off >= minoff; --off) 192 if (map[off] != 0) 193 return (off * NDENTRIES + flsl(map[off]) - 1); 194 return (low - 1); 195 } 196 197 static int 198 fdisused(struct filedesc *fdp, int fd) 199 { 200 KASSERT(fd >= 0 && fd < fdp->fd_nfiles, 201 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles)); 202 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0); 203 } 204 205 /* 206 * Mark a file descriptor as used. 207 */ 208 static void 209 fdused(struct filedesc *fdp, int fd) 210 { 211 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 212 KASSERT(!fdisused(fdp, fd), 213 ("fd already used")); 214 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd); 215 if (fd > fdp->fd_lastfile) 216 fdp->fd_lastfile = fd; 217 if (fd == fdp->fd_freefile) 218 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 219 } 220 221 /* 222 * Mark a file descriptor as unused. 223 */ 224 static void 225 fdunused(struct filedesc *fdp, int fd) 226 { 227 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 228 KASSERT(fdisused(fdp, fd), 229 ("fd is already unused")); 230 KASSERT(fdp->fd_ofiles[fd] == NULL, 231 ("fd is still in use")); 232 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd); 233 if (fd < fdp->fd_freefile) 234 fdp->fd_freefile = fd; 235 if (fd == fdp->fd_lastfile) 236 fdp->fd_lastfile = fd_last_used(fdp, 0, fd); 237 } 238 239 /* 240 * System calls on descriptors. 241 */ 242 #ifndef _SYS_SYSPROTO_H_ 243 struct getdtablesize_args { 244 int dummy; 245 }; 246 #endif 247 /* 248 * MPSAFE 249 */ 250 /* ARGSUSED */ 251 int 252 getdtablesize(struct thread *td, struct getdtablesize_args *uap) 253 { 254 struct proc *p = td->td_proc; 255 256 PROC_LOCK(p); 257 td->td_retval[0] = 258 min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 259 PROC_UNLOCK(p); 260 return (0); 261 } 262 263 /* 264 * Duplicate a file descriptor to a particular value. 265 * 266 * note: keep in mind that a potential race condition exists when closing 267 * descriptors from a shared descriptor table (via rfork). 268 */ 269 #ifndef _SYS_SYSPROTO_H_ 270 struct dup2_args { 271 u_int from; 272 u_int to; 273 }; 274 #endif 275 /* 276 * MPSAFE 277 */ 278 /* ARGSUSED */ 279 int 280 dup2(struct thread *td, struct dup2_args *uap) 281 { 282 283 return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to, 284 td->td_retval)); 285 } 286 287 /* 288 * Duplicate a file descriptor. 289 */ 290 #ifndef _SYS_SYSPROTO_H_ 291 struct dup_args { 292 u_int fd; 293 }; 294 #endif 295 /* 296 * MPSAFE 297 */ 298 /* ARGSUSED */ 299 int 300 dup(struct thread *td, struct dup_args *uap) 301 { 302 303 return (do_dup(td, DUP_VARIABLE, (int)uap->fd, 0, td->td_retval)); 304 } 305 306 /* 307 * The file control system call. 308 */ 309 #ifndef _SYS_SYSPROTO_H_ 310 struct fcntl_args { 311 int fd; 312 int cmd; 313 long arg; 314 }; 315 #endif 316 /* 317 * MPSAFE 318 */ 319 /* ARGSUSED */ 320 int 321 fcntl(struct thread *td, struct fcntl_args *uap) 322 { 323 struct flock fl; 324 intptr_t arg; 325 int error; 326 327 error = 0; 328 switch (uap->cmd) { 329 case F_GETLK: 330 case F_SETLK: 331 case F_SETLKW: 332 error = copyin((void *)(intptr_t)uap->arg, &fl, sizeof(fl)); 333 arg = (intptr_t)&fl; 334 break; 335 default: 336 arg = uap->arg; 337 break; 338 } 339 if (error) 340 return (error); 341 error = kern_fcntl(td, uap->fd, uap->cmd, arg); 342 if (error) 343 return (error); 344 if (uap->cmd == F_GETLK) 345 error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl)); 346 return (error); 347 } 348 349 int 350 kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) 351 { 352 struct filedesc *fdp; 353 struct flock *flp; 354 struct file *fp; 355 struct proc *p; 356 char *pop; 357 struct vnode *vp; 358 u_int newmin; 359 int error, flg, tmp; 360 int giant_locked; 361 362 /* 363 * XXXRW: Some fcntl() calls require Giant -- others don't. Try to 364 * avoid grabbing Giant for calls we know don't need it. 365 */ 366 switch (cmd) { 367 case F_DUPFD: 368 case F_GETFD: 369 case F_SETFD: 370 case F_GETFL: 371 giant_locked = 0; 372 break; 373 374 default: 375 giant_locked = 1; 376 mtx_lock(&Giant); 377 } 378 379 error = 0; 380 flg = F_POSIX; 381 p = td->td_proc; 382 fdp = p->p_fd; 383 FILEDESC_LOCK(fdp); 384 if ((unsigned)fd >= fdp->fd_nfiles || 385 (fp = fdp->fd_ofiles[fd]) == NULL) { 386 FILEDESC_UNLOCK(fdp); 387 error = EBADF; 388 goto done2; 389 } 390 pop = &fdp->fd_ofileflags[fd]; 391 392 switch (cmd) { 393 case F_DUPFD: 394 /* mtx_assert(&Giant, MA_NOTOWNED); */ 395 FILEDESC_UNLOCK(fdp); 396 newmin = arg; 397 PROC_LOCK(p); 398 if (newmin >= lim_cur(p, RLIMIT_NOFILE) || 399 newmin >= maxfilesperproc) { 400 PROC_UNLOCK(p); 401 error = EINVAL; 402 break; 403 } 404 PROC_UNLOCK(p); 405 error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval); 406 break; 407 408 case F_GETFD: 409 /* mtx_assert(&Giant, MA_NOTOWNED); */ 410 td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0; 411 FILEDESC_UNLOCK(fdp); 412 break; 413 414 case F_SETFD: 415 /* mtx_assert(&Giant, MA_NOTOWNED); */ 416 *pop = (*pop &~ UF_EXCLOSE) | 417 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0); 418 FILEDESC_UNLOCK(fdp); 419 break; 420 421 case F_GETFL: 422 /* mtx_assert(&Giant, MA_NOTOWNED); */ 423 FILE_LOCK(fp); 424 td->td_retval[0] = OFLAGS(fp->f_flag); 425 FILE_UNLOCK(fp); 426 FILEDESC_UNLOCK(fdp); 427 break; 428 429 case F_SETFL: 430 mtx_assert(&Giant, MA_OWNED); 431 FILE_LOCK(fp); 432 fhold_locked(fp); 433 fp->f_flag &= ~FCNTLFLAGS; 434 fp->f_flag |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS; 435 FILE_UNLOCK(fp); 436 FILEDESC_UNLOCK(fdp); 437 tmp = fp->f_flag & FNONBLOCK; 438 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 439 if (error) { 440 fdrop(fp, td); 441 break; 442 } 443 tmp = fp->f_flag & FASYNC; 444 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); 445 if (error == 0) { 446 fdrop(fp, td); 447 break; 448 } 449 FILE_LOCK(fp); 450 fp->f_flag &= ~FNONBLOCK; 451 FILE_UNLOCK(fp); 452 tmp = 0; 453 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 454 fdrop(fp, td); 455 break; 456 457 case F_GETOWN: 458 mtx_assert(&Giant, MA_OWNED); 459 fhold(fp); 460 FILEDESC_UNLOCK(fdp); 461 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td); 462 if (error == 0) 463 td->td_retval[0] = tmp; 464 fdrop(fp, td); 465 break; 466 467 case F_SETOWN: 468 mtx_assert(&Giant, MA_OWNED); 469 fhold(fp); 470 FILEDESC_UNLOCK(fdp); 471 tmp = arg; 472 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td); 473 fdrop(fp, td); 474 break; 475 476 case F_SETLKW: 477 mtx_assert(&Giant, MA_OWNED); 478 flg |= F_WAIT; 479 /* FALLTHROUGH F_SETLK */ 480 481 case F_SETLK: 482 mtx_assert(&Giant, MA_OWNED); 483 if (fp->f_type != DTYPE_VNODE) { 484 FILEDESC_UNLOCK(fdp); 485 error = EBADF; 486 break; 487 } 488 489 flp = (struct flock *)arg; 490 if (flp->l_whence == SEEK_CUR) { 491 if (fp->f_offset < 0 || 492 (flp->l_start > 0 && 493 fp->f_offset > OFF_MAX - flp->l_start)) { 494 FILEDESC_UNLOCK(fdp); 495 error = EOVERFLOW; 496 break; 497 } 498 flp->l_start += fp->f_offset; 499 } 500 501 /* 502 * VOP_ADVLOCK() may block. 503 */ 504 fhold(fp); 505 FILEDESC_UNLOCK(fdp); 506 vp = fp->f_vnode; 507 508 switch (flp->l_type) { 509 case F_RDLCK: 510 if ((fp->f_flag & FREAD) == 0) { 511 error = EBADF; 512 break; 513 } 514 PROC_LOCK(p->p_leader); 515 p->p_leader->p_flag |= P_ADVLOCK; 516 PROC_UNLOCK(p->p_leader); 517 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 518 flp, flg); 519 break; 520 case F_WRLCK: 521 if ((fp->f_flag & FWRITE) == 0) { 522 error = EBADF; 523 break; 524 } 525 PROC_LOCK(p->p_leader); 526 p->p_leader->p_flag |= P_ADVLOCK; 527 PROC_UNLOCK(p->p_leader); 528 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 529 flp, flg); 530 break; 531 case F_UNLCK: 532 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 533 flp, F_POSIX); 534 break; 535 default: 536 error = EINVAL; 537 break; 538 } 539 /* Check for race with close */ 540 FILEDESC_LOCK_FAST(fdp); 541 if ((unsigned) fd >= fdp->fd_nfiles || 542 fp != fdp->fd_ofiles[fd]) { 543 FILEDESC_UNLOCK_FAST(fdp); 544 flp->l_whence = SEEK_SET; 545 flp->l_start = 0; 546 flp->l_len = 0; 547 flp->l_type = F_UNLCK; 548 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 549 F_UNLCK, flp, F_POSIX); 550 } else 551 FILEDESC_UNLOCK_FAST(fdp); 552 fdrop(fp, td); 553 break; 554 555 case F_GETLK: 556 mtx_assert(&Giant, MA_OWNED); 557 if (fp->f_type != DTYPE_VNODE) { 558 FILEDESC_UNLOCK(fdp); 559 error = EBADF; 560 break; 561 } 562 flp = (struct flock *)arg; 563 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK && 564 flp->l_type != F_UNLCK) { 565 FILEDESC_UNLOCK(fdp); 566 error = EINVAL; 567 break; 568 } 569 if (flp->l_whence == SEEK_CUR) { 570 if ((flp->l_start > 0 && 571 fp->f_offset > OFF_MAX - flp->l_start) || 572 (flp->l_start < 0 && 573 fp->f_offset < OFF_MIN - flp->l_start)) { 574 FILEDESC_UNLOCK(fdp); 575 error = EOVERFLOW; 576 break; 577 } 578 flp->l_start += fp->f_offset; 579 } 580 /* 581 * VOP_ADVLOCK() may block. 582 */ 583 fhold(fp); 584 FILEDESC_UNLOCK(fdp); 585 vp = fp->f_vnode; 586 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp, 587 F_POSIX); 588 fdrop(fp, td); 589 break; 590 default: 591 FILEDESC_UNLOCK(fdp); 592 error = EINVAL; 593 break; 594 } 595 done2: 596 if (giant_locked) 597 mtx_unlock(&Giant); 598 return (error); 599 } 600 601 /* 602 * Common code for dup, dup2, and fcntl(F_DUPFD). 603 */ 604 static int 605 do_dup(struct thread *td, enum dup_type type, int old, int new, register_t *retval) 606 { 607 struct filedesc *fdp; 608 struct proc *p; 609 struct file *fp; 610 struct file *delfp; 611 int error, holdleaders, maxfd; 612 613 KASSERT((type == DUP_VARIABLE || type == DUP_FIXED), 614 ("invalid dup type %d", type)); 615 616 p = td->td_proc; 617 fdp = p->p_fd; 618 619 /* 620 * Verify we have a valid descriptor to dup from and possibly to 621 * dup to. 622 */ 623 if (old < 0 || new < 0) 624 return (EBADF); 625 PROC_LOCK(p); 626 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 627 PROC_UNLOCK(p); 628 if (new >= maxfd) 629 return (EMFILE); 630 631 FILEDESC_LOCK(fdp); 632 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) { 633 FILEDESC_UNLOCK(fdp); 634 return (EBADF); 635 } 636 if (type == DUP_FIXED && old == new) { 637 *retval = new; 638 FILEDESC_UNLOCK(fdp); 639 return (0); 640 } 641 fp = fdp->fd_ofiles[old]; 642 fhold(fp); 643 644 /* 645 * If the caller specified a file descriptor, make sure the file 646 * table is large enough to hold it, and grab it. Otherwise, just 647 * allocate a new descriptor the usual way. Since the filedesc 648 * lock may be temporarily dropped in the process, we have to look 649 * out for a race. 650 */ 651 if (type == DUP_FIXED) { 652 if (new >= fdp->fd_nfiles) 653 fdgrowtable(fdp, new + 1); 654 if (fdp->fd_ofiles[new] == NULL) 655 fdused(fdp, new); 656 } else { 657 if ((error = fdalloc(td, new, &new)) != 0) { 658 FILEDESC_UNLOCK(fdp); 659 fdrop(fp, td); 660 return (error); 661 } 662 } 663 664 /* 665 * If the old file changed out from under us then treat it as a 666 * bad file descriptor. Userland should do its own locking to 667 * avoid this case. 668 */ 669 if (fdp->fd_ofiles[old] != fp || 670 (fdp->fd_ofileflags[old] & UF_OPENING) != 0 || 671 (fdp->fd_ofileflags[new] & UF_OPENING) != 0) { 672 /* we've allocated a descriptor which we won't use */ 673 if (fdp->fd_ofiles[new] == NULL) 674 fdunused(fdp, new); 675 FILEDESC_UNLOCK(fdp); 676 fdrop(fp, td); 677 return (EBADF); 678 } 679 KASSERT(old != new, 680 ("new fd is same as old")); 681 682 /* 683 * Save info on the descriptor being overwritten. We cannot close 684 * it without introducing an ownership race for the slot, since we 685 * need to drop the filedesc lock to call closef(). 686 * 687 * XXX this duplicates parts of close(). 688 */ 689 delfp = fdp->fd_ofiles[new]; 690 holdleaders = 0; 691 if (delfp != NULL) { 692 if (td->td_proc->p_fdtol != NULL) { 693 /* 694 * Ask fdfree() to sleep to ensure that all relevant 695 * process leaders can be traversed in closef(). 696 */ 697 fdp->fd_holdleaderscount++; 698 holdleaders = 1; 699 } 700 } 701 702 /* 703 * Duplicate the source descriptor 704 */ 705 fdp->fd_ofiles[new] = fp; 706 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE; 707 if (new > fdp->fd_lastfile) 708 fdp->fd_lastfile = new; 709 *retval = new; 710 711 /* 712 * If we dup'd over a valid file, we now own the reference to it 713 * and must dispose of it using closef() semantics (as if a 714 * close() were performed on it). 715 * 716 * XXX this duplicates parts of close(). 717 */ 718 if (delfp != NULL) { 719 knote_fdclose(td, new); 720 FILEDESC_UNLOCK(fdp); 721 (void) closef(delfp, td); 722 if (holdleaders) { 723 FILEDESC_LOCK_FAST(fdp); 724 fdp->fd_holdleaderscount--; 725 if (fdp->fd_holdleaderscount == 0 && 726 fdp->fd_holdleaderswakeup != 0) { 727 fdp->fd_holdleaderswakeup = 0; 728 wakeup(&fdp->fd_holdleaderscount); 729 } 730 FILEDESC_UNLOCK_FAST(fdp); 731 } 732 } else { 733 FILEDESC_UNLOCK(fdp); 734 } 735 return (0); 736 } 737 738 /* 739 * If sigio is on the list associated with a process or process group, 740 * disable signalling from the device, remove sigio from the list and 741 * free sigio. 742 */ 743 void 744 funsetown(struct sigio **sigiop) 745 { 746 struct sigio *sigio; 747 748 SIGIO_LOCK(); 749 sigio = *sigiop; 750 if (sigio == NULL) { 751 SIGIO_UNLOCK(); 752 return; 753 } 754 *(sigio->sio_myref) = NULL; 755 if ((sigio)->sio_pgid < 0) { 756 struct pgrp *pg = (sigio)->sio_pgrp; 757 PGRP_LOCK(pg); 758 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 759 sigio, sio_pgsigio); 760 PGRP_UNLOCK(pg); 761 } else { 762 struct proc *p = (sigio)->sio_proc; 763 PROC_LOCK(p); 764 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 765 sigio, sio_pgsigio); 766 PROC_UNLOCK(p); 767 } 768 SIGIO_UNLOCK(); 769 crfree(sigio->sio_ucred); 770 FREE(sigio, M_SIGIO); 771 } 772 773 /* 774 * Free a list of sigio structures. 775 * We only need to lock the SIGIO_LOCK because we have made ourselves 776 * inaccessible to callers of fsetown and therefore do not need to lock 777 * the proc or pgrp struct for the list manipulation. 778 */ 779 void 780 funsetownlst(struct sigiolst *sigiolst) 781 { 782 struct proc *p; 783 struct pgrp *pg; 784 struct sigio *sigio; 785 786 sigio = SLIST_FIRST(sigiolst); 787 if (sigio == NULL) 788 return; 789 p = NULL; 790 pg = NULL; 791 792 /* 793 * Every entry of the list should belong 794 * to a single proc or pgrp. 795 */ 796 if (sigio->sio_pgid < 0) { 797 pg = sigio->sio_pgrp; 798 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED); 799 } else /* if (sigio->sio_pgid > 0) */ { 800 p = sigio->sio_proc; 801 PROC_LOCK_ASSERT(p, MA_NOTOWNED); 802 } 803 804 SIGIO_LOCK(); 805 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) { 806 *(sigio->sio_myref) = NULL; 807 if (pg != NULL) { 808 KASSERT(sigio->sio_pgid < 0, 809 ("Proc sigio in pgrp sigio list")); 810 KASSERT(sigio->sio_pgrp == pg, 811 ("Bogus pgrp in sigio list")); 812 PGRP_LOCK(pg); 813 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio, 814 sio_pgsigio); 815 PGRP_UNLOCK(pg); 816 } else /* if (p != NULL) */ { 817 KASSERT(sigio->sio_pgid > 0, 818 ("Pgrp sigio in proc sigio list")); 819 KASSERT(sigio->sio_proc == p, 820 ("Bogus proc in sigio list")); 821 PROC_LOCK(p); 822 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, 823 sio_pgsigio); 824 PROC_UNLOCK(p); 825 } 826 SIGIO_UNLOCK(); 827 crfree(sigio->sio_ucred); 828 FREE(sigio, M_SIGIO); 829 SIGIO_LOCK(); 830 } 831 SIGIO_UNLOCK(); 832 } 833 834 /* 835 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 836 * 837 * After permission checking, add a sigio structure to the sigio list for 838 * the process or process group. 839 */ 840 int 841 fsetown(pid_t pgid, struct sigio **sigiop) 842 { 843 struct proc *proc; 844 struct pgrp *pgrp; 845 struct sigio *sigio; 846 int ret; 847 848 if (pgid == 0) { 849 funsetown(sigiop); 850 return (0); 851 } 852 853 ret = 0; 854 855 /* Allocate and fill in the new sigio out of locks. */ 856 MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK); 857 sigio->sio_pgid = pgid; 858 sigio->sio_ucred = crhold(curthread->td_ucred); 859 sigio->sio_myref = sigiop; 860 861 sx_slock(&proctree_lock); 862 if (pgid > 0) { 863 proc = pfind(pgid); 864 if (proc == NULL) { 865 ret = ESRCH; 866 goto fail; 867 } 868 869 /* 870 * Policy - Don't allow a process to FSETOWN a process 871 * in another session. 872 * 873 * Remove this test to allow maximum flexibility or 874 * restrict FSETOWN to the current process or process 875 * group for maximum safety. 876 */ 877 PROC_UNLOCK(proc); 878 if (proc->p_session != curthread->td_proc->p_session) { 879 ret = EPERM; 880 goto fail; 881 } 882 883 pgrp = NULL; 884 } else /* if (pgid < 0) */ { 885 pgrp = pgfind(-pgid); 886 if (pgrp == NULL) { 887 ret = ESRCH; 888 goto fail; 889 } 890 PGRP_UNLOCK(pgrp); 891 892 /* 893 * Policy - Don't allow a process to FSETOWN a process 894 * in another session. 895 * 896 * Remove this test to allow maximum flexibility or 897 * restrict FSETOWN to the current process or process 898 * group for maximum safety. 899 */ 900 if (pgrp->pg_session != curthread->td_proc->p_session) { 901 ret = EPERM; 902 goto fail; 903 } 904 905 proc = NULL; 906 } 907 funsetown(sigiop); 908 if (pgid > 0) { 909 PROC_LOCK(proc); 910 /* 911 * Since funsetownlst() is called without the proctree 912 * locked, we need to check for P_WEXIT. 913 * XXX: is ESRCH correct? 914 */ 915 if ((proc->p_flag & P_WEXIT) != 0) { 916 PROC_UNLOCK(proc); 917 ret = ESRCH; 918 goto fail; 919 } 920 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 921 sigio->sio_proc = proc; 922 PROC_UNLOCK(proc); 923 } else { 924 PGRP_LOCK(pgrp); 925 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 926 sigio->sio_pgrp = pgrp; 927 PGRP_UNLOCK(pgrp); 928 } 929 sx_sunlock(&proctree_lock); 930 SIGIO_LOCK(); 931 *sigiop = sigio; 932 SIGIO_UNLOCK(); 933 return (0); 934 935 fail: 936 sx_sunlock(&proctree_lock); 937 crfree(sigio->sio_ucred); 938 FREE(sigio, M_SIGIO); 939 return (ret); 940 } 941 942 /* 943 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 944 */ 945 pid_t 946 fgetown(sigiop) 947 struct sigio **sigiop; 948 { 949 pid_t pgid; 950 951 SIGIO_LOCK(); 952 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0; 953 SIGIO_UNLOCK(); 954 return (pgid); 955 } 956 957 /* 958 * Close a file descriptor. 959 */ 960 #ifndef _SYS_SYSPROTO_H_ 961 struct close_args { 962 int fd; 963 }; 964 #endif 965 /* 966 * MPSAFE 967 */ 968 /* ARGSUSED */ 969 int 970 close(td, uap) 971 struct thread *td; 972 struct close_args *uap; 973 { 974 975 return (kern_close(td, uap->fd)); 976 } 977 978 int 979 kern_close(td, fd) 980 struct thread *td; 981 int fd; 982 { 983 struct filedesc *fdp; 984 struct file *fp; 985 int error; 986 int holdleaders; 987 988 error = 0; 989 holdleaders = 0; 990 fdp = td->td_proc->p_fd; 991 992 AUDIT_SYSCLOSE(td, fd); 993 994 FILEDESC_LOCK(fdp); 995 if ((unsigned)fd >= fdp->fd_nfiles || 996 (fp = fdp->fd_ofiles[fd]) == NULL || 997 (fdp->fd_ofileflags[fd] & UF_OPENING) != 0) { 998 FILEDESC_UNLOCK(fdp); 999 return (EBADF); 1000 } 1001 fdp->fd_ofiles[fd] = NULL; 1002 fdp->fd_ofileflags[fd] = 0; 1003 fdunused(fdp, fd); 1004 if (td->td_proc->p_fdtol != NULL) { 1005 /* 1006 * Ask fdfree() to sleep to ensure that all relevant 1007 * process leaders can be traversed in closef(). 1008 */ 1009 fdp->fd_holdleaderscount++; 1010 holdleaders = 1; 1011 } 1012 1013 /* 1014 * We now hold the fp reference that used to be owned by the descriptor 1015 * array. 1016 * We have to unlock the FILEDESC *AFTER* knote_fdclose to prevent a 1017 * race of the fd getting opened, a knote added, and deleteing a knote 1018 * for the new fd. 1019 */ 1020 knote_fdclose(td, fd); 1021 FILEDESC_UNLOCK(fdp); 1022 1023 error = closef(fp, td); 1024 if (holdleaders) { 1025 FILEDESC_LOCK_FAST(fdp); 1026 fdp->fd_holdleaderscount--; 1027 if (fdp->fd_holdleaderscount == 0 && 1028 fdp->fd_holdleaderswakeup != 0) { 1029 fdp->fd_holdleaderswakeup = 0; 1030 wakeup(&fdp->fd_holdleaderscount); 1031 } 1032 FILEDESC_UNLOCK_FAST(fdp); 1033 } 1034 return (error); 1035 } 1036 1037 #if defined(COMPAT_43) 1038 /* 1039 * Return status information about a file descriptor. 1040 */ 1041 #ifndef _SYS_SYSPROTO_H_ 1042 struct ofstat_args { 1043 int fd; 1044 struct ostat *sb; 1045 }; 1046 #endif 1047 /* 1048 * MPSAFE 1049 */ 1050 /* ARGSUSED */ 1051 int 1052 ofstat(struct thread *td, struct ofstat_args *uap) 1053 { 1054 struct ostat oub; 1055 struct stat ub; 1056 int error; 1057 1058 error = kern_fstat(td, uap->fd, &ub); 1059 if (error == 0) { 1060 cvtstat(&ub, &oub); 1061 error = copyout(&oub, uap->sb, sizeof(oub)); 1062 } 1063 return (error); 1064 } 1065 #endif /* COMPAT_43 */ 1066 1067 /* 1068 * Return status information about a file descriptor. 1069 */ 1070 #ifndef _SYS_SYSPROTO_H_ 1071 struct fstat_args { 1072 int fd; 1073 struct stat *sb; 1074 }; 1075 #endif 1076 /* 1077 * MPSAFE 1078 */ 1079 /* ARGSUSED */ 1080 int 1081 fstat(struct thread *td, struct fstat_args *uap) 1082 { 1083 struct stat ub; 1084 int error; 1085 1086 error = kern_fstat(td, uap->fd, &ub); 1087 if (error == 0) 1088 error = copyout(&ub, uap->sb, sizeof(ub)); 1089 return (error); 1090 } 1091 1092 int 1093 kern_fstat(struct thread *td, int fd, struct stat *sbp) 1094 { 1095 struct file *fp; 1096 int error; 1097 1098 AUDIT_ARG(fd, fd); 1099 1100 if ((error = fget(td, fd, &fp)) != 0) 1101 return (error); 1102 1103 AUDIT_ARG(file, td->td_proc, fp); 1104 1105 error = fo_stat(fp, sbp, td->td_ucred, td); 1106 fdrop(fp, td); 1107 return (error); 1108 } 1109 1110 /* 1111 * Return status information about a file descriptor. 1112 */ 1113 #ifndef _SYS_SYSPROTO_H_ 1114 struct nfstat_args { 1115 int fd; 1116 struct nstat *sb; 1117 }; 1118 #endif 1119 /* 1120 * MPSAFE 1121 */ 1122 /* ARGSUSED */ 1123 int 1124 nfstat(struct thread *td, struct nfstat_args *uap) 1125 { 1126 struct nstat nub; 1127 struct stat ub; 1128 int error; 1129 1130 error = kern_fstat(td, uap->fd, &ub); 1131 if (error == 0) { 1132 cvtnstat(&ub, &nub); 1133 error = copyout(&nub, uap->sb, sizeof(nub)); 1134 } 1135 return (error); 1136 } 1137 1138 /* 1139 * Return pathconf information about a file descriptor. 1140 */ 1141 #ifndef _SYS_SYSPROTO_H_ 1142 struct fpathconf_args { 1143 int fd; 1144 int name; 1145 }; 1146 #endif 1147 /* 1148 * MPSAFE 1149 */ 1150 /* ARGSUSED */ 1151 int 1152 fpathconf(struct thread *td, struct fpathconf_args *uap) 1153 { 1154 struct file *fp; 1155 struct vnode *vp; 1156 int error; 1157 1158 if ((error = fget(td, uap->fd, &fp)) != 0) 1159 return (error); 1160 1161 /* If asynchronous I/O is available, it works for all descriptors. */ 1162 if (uap->name == _PC_ASYNC_IO) { 1163 td->td_retval[0] = async_io_version; 1164 goto out; 1165 } 1166 vp = fp->f_vnode; 1167 if (vp != NULL) { 1168 int vfslocked; 1169 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 1170 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 1171 error = VOP_PATHCONF(vp, uap->name, td->td_retval); 1172 VOP_UNLOCK(vp, 0, td); 1173 VFS_UNLOCK_GIANT(vfslocked); 1174 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) { 1175 if (uap->name != _PC_PIPE_BUF) { 1176 error = EINVAL; 1177 } else { 1178 td->td_retval[0] = PIPE_BUF; 1179 error = 0; 1180 } 1181 } else { 1182 error = EOPNOTSUPP; 1183 } 1184 out: 1185 fdrop(fp, td); 1186 return (error); 1187 } 1188 1189 /* 1190 * Grow the file table to accomodate (at least) nfd descriptors. This may 1191 * block and drop the filedesc lock, but it will reacquire it before 1192 * returning. 1193 */ 1194 static void 1195 fdgrowtable(struct filedesc *fdp, int nfd) 1196 { 1197 struct file **ntable; 1198 char *nfileflags; 1199 int nnfiles, onfiles; 1200 NDSLOTTYPE *nmap; 1201 1202 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1203 1204 KASSERT(fdp->fd_nfiles > 0, 1205 ("zero-length file table")); 1206 1207 /* compute the size of the new table */ 1208 onfiles = fdp->fd_nfiles; 1209 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */ 1210 if (nnfiles <= onfiles) 1211 /* the table is already large enough */ 1212 return; 1213 1214 /* allocate a new table and (if required) new bitmaps */ 1215 FILEDESC_UNLOCK(fdp); 1216 MALLOC(ntable, struct file **, nnfiles * OFILESIZE, 1217 M_FILEDESC, M_ZERO | M_WAITOK); 1218 nfileflags = (char *)&ntable[nnfiles]; 1219 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) 1220 MALLOC(nmap, NDSLOTTYPE *, NDSLOTS(nnfiles) * NDSLOTSIZE, 1221 M_FILEDESC, M_ZERO | M_WAITOK); 1222 else 1223 nmap = NULL; 1224 FILEDESC_LOCK(fdp); 1225 1226 /* 1227 * We now have new tables ready to go. Since we dropped the 1228 * filedesc lock to call malloc(), watch out for a race. 1229 */ 1230 onfiles = fdp->fd_nfiles; 1231 if (onfiles >= nnfiles) { 1232 /* we lost the race, but that's OK */ 1233 free(ntable, M_FILEDESC); 1234 if (nmap != NULL) 1235 free(nmap, M_FILEDESC); 1236 return; 1237 } 1238 bcopy(fdp->fd_ofiles, ntable, onfiles * sizeof(*ntable)); 1239 bcopy(fdp->fd_ofileflags, nfileflags, onfiles); 1240 if (onfiles > NDFILE) 1241 free(fdp->fd_ofiles, M_FILEDESC); 1242 fdp->fd_ofiles = ntable; 1243 fdp->fd_ofileflags = nfileflags; 1244 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) { 1245 bcopy(fdp->fd_map, nmap, NDSLOTS(onfiles) * sizeof(*nmap)); 1246 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE)) 1247 free(fdp->fd_map, M_FILEDESC); 1248 fdp->fd_map = nmap; 1249 } 1250 fdp->fd_nfiles = nnfiles; 1251 } 1252 1253 /* 1254 * Allocate a file descriptor for the process. 1255 */ 1256 int 1257 fdalloc(struct thread *td, int minfd, int *result) 1258 { 1259 struct proc *p = td->td_proc; 1260 struct filedesc *fdp = p->p_fd; 1261 int fd = -1, maxfd; 1262 1263 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1264 1265 if (fdp->fd_freefile > minfd) 1266 minfd = fdp->fd_freefile; 1267 1268 PROC_LOCK(p); 1269 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1270 PROC_UNLOCK(p); 1271 1272 /* 1273 * Search the bitmap for a free descriptor. If none is found, try 1274 * to grow the file table. Keep at it until we either get a file 1275 * descriptor or run into process or system limits; fdgrowtable() 1276 * may drop the filedesc lock, so we're in a race. 1277 */ 1278 for (;;) { 1279 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); 1280 if (fd >= maxfd) 1281 return (EMFILE); 1282 if (fd < fdp->fd_nfiles) 1283 break; 1284 fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd)); 1285 } 1286 1287 /* 1288 * Perform some sanity checks, then mark the file descriptor as 1289 * used and return it to the caller. 1290 */ 1291 KASSERT(!fdisused(fdp, fd), 1292 ("fd_first_free() returned non-free descriptor")); 1293 KASSERT(fdp->fd_ofiles[fd] == NULL, 1294 ("free descriptor isn't")); 1295 fdp->fd_ofileflags[fd] = 0; /* XXX needed? */ 1296 fdused(fdp, fd); 1297 *result = fd; 1298 return (0); 1299 } 1300 1301 /* 1302 * Check to see whether n user file descriptors 1303 * are available to the process p. 1304 */ 1305 int 1306 fdavail(struct thread *td, int n) 1307 { 1308 struct proc *p = td->td_proc; 1309 struct filedesc *fdp = td->td_proc->p_fd; 1310 struct file **fpp; 1311 int i, lim, last; 1312 1313 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1314 1315 PROC_LOCK(p); 1316 lim = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1317 PROC_UNLOCK(p); 1318 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) 1319 return (1); 1320 last = min(fdp->fd_nfiles, lim); 1321 fpp = &fdp->fd_ofiles[fdp->fd_freefile]; 1322 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) { 1323 if (*fpp == NULL && --n <= 0) 1324 return (1); 1325 } 1326 return (0); 1327 } 1328 1329 /* 1330 * Create a new open file structure and allocate 1331 * a file decriptor for the process that refers to it. 1332 * We add one reference to the file for the descriptor table 1333 * and one reference for resultfp. This is to prevent us being 1334 * preempted and the entry in the descriptor table closed after 1335 * we release the FILEDESC lock. 1336 */ 1337 int 1338 falloc(struct thread *td, struct file **resultfp, int *resultfd) 1339 { 1340 struct proc *p = td->td_proc; 1341 struct file *fp, *fq; 1342 int error, i; 1343 int maxuserfiles = maxfiles - (maxfiles / 20); 1344 static struct timeval lastfail; 1345 static int curfail; 1346 1347 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO); 1348 sx_xlock(&filelist_lock); 1349 1350 if ((openfiles >= maxuserfiles && 1351 suser_cred(td->td_ucred, SUSER_RUID) != 0) || 1352 openfiles >= maxfiles) { 1353 if (ppsratecheck(&lastfail, &curfail, 1)) { 1354 printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n", 1355 td->td_ucred->cr_ruid); 1356 } 1357 sx_xunlock(&filelist_lock); 1358 uma_zfree(file_zone, fp); 1359 return (ENFILE); 1360 } 1361 openfiles++; 1362 1363 /* 1364 * If the process has file descriptor zero open, add the new file 1365 * descriptor to the list of open files at that point, otherwise 1366 * put it at the front of the list of open files. 1367 */ 1368 fp->f_mtxp = mtx_pool_alloc(mtxpool_sleep); 1369 fp->f_count = 1; 1370 if (resultfp) 1371 fp->f_count++; 1372 fp->f_cred = crhold(td->td_ucred); 1373 fp->f_ops = &badfileops; 1374 fp->f_data = NULL; 1375 fp->f_vnode = NULL; 1376 FILEDESC_LOCK(p->p_fd); 1377 if ((fq = p->p_fd->fd_ofiles[0])) { 1378 LIST_INSERT_AFTER(fq, fp, f_list); 1379 } else { 1380 LIST_INSERT_HEAD(&filehead, fp, f_list); 1381 } 1382 sx_xunlock(&filelist_lock); 1383 if ((error = fdalloc(td, 0, &i))) { 1384 FILEDESC_UNLOCK(p->p_fd); 1385 fdrop(fp, td); 1386 if (resultfp) 1387 fdrop(fp, td); 1388 return (error); 1389 } 1390 p->p_fd->fd_ofiles[i] = fp; 1391 FILEDESC_UNLOCK(p->p_fd); 1392 if (resultfp) 1393 *resultfp = fp; 1394 if (resultfd) 1395 *resultfd = i; 1396 return (0); 1397 } 1398 1399 /* 1400 * Build a new filedesc structure from another. 1401 * Copy the current, root, and jail root vnode references. 1402 */ 1403 struct filedesc * 1404 fdinit(struct filedesc *fdp) 1405 { 1406 struct filedesc0 *newfdp; 1407 1408 newfdp = malloc(sizeof *newfdp, M_FILEDESC, M_WAITOK | M_ZERO); 1409 mtx_init(&newfdp->fd_fd.fd_mtx, FILEDESC_LOCK_DESC, NULL, MTX_DEF); 1410 if (fdp != NULL) { 1411 FILEDESC_LOCK(fdp); 1412 newfdp->fd_fd.fd_cdir = fdp->fd_cdir; 1413 if (newfdp->fd_fd.fd_cdir) 1414 VREF(newfdp->fd_fd.fd_cdir); 1415 newfdp->fd_fd.fd_rdir = fdp->fd_rdir; 1416 if (newfdp->fd_fd.fd_rdir) 1417 VREF(newfdp->fd_fd.fd_rdir); 1418 newfdp->fd_fd.fd_jdir = fdp->fd_jdir; 1419 if (newfdp->fd_fd.fd_jdir) 1420 VREF(newfdp->fd_fd.fd_jdir); 1421 FILEDESC_UNLOCK(fdp); 1422 } 1423 1424 /* Create the file descriptor table. */ 1425 newfdp->fd_fd.fd_refcnt = 1; 1426 newfdp->fd_fd.fd_holdcnt = 1; 1427 newfdp->fd_fd.fd_cmask = CMASK; 1428 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; 1429 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; 1430 newfdp->fd_fd.fd_nfiles = NDFILE; 1431 newfdp->fd_fd.fd_map = newfdp->fd_dmap; 1432 newfdp->fd_fd.fd_lastfile = -1; 1433 return (&newfdp->fd_fd); 1434 } 1435 1436 static struct filedesc * 1437 fdhold(struct proc *p) 1438 { 1439 struct filedesc *fdp; 1440 1441 mtx_lock(&fdesc_mtx); 1442 fdp = p->p_fd; 1443 if (fdp != NULL) 1444 fdp->fd_holdcnt++; 1445 mtx_unlock(&fdesc_mtx); 1446 return (fdp); 1447 } 1448 1449 static void 1450 fddrop(struct filedesc *fdp) 1451 { 1452 int i; 1453 1454 mtx_lock(&fdesc_mtx); 1455 i = --fdp->fd_holdcnt; 1456 mtx_unlock(&fdesc_mtx); 1457 if (i > 0) 1458 return; 1459 1460 mtx_destroy(&fdp->fd_mtx); 1461 FREE(fdp, M_FILEDESC); 1462 } 1463 1464 /* 1465 * Share a filedesc structure. 1466 */ 1467 struct filedesc * 1468 fdshare(struct filedesc *fdp) 1469 { 1470 FILEDESC_LOCK_FAST(fdp); 1471 fdp->fd_refcnt++; 1472 FILEDESC_UNLOCK_FAST(fdp); 1473 return (fdp); 1474 } 1475 1476 /* 1477 * Unshare a filedesc structure, if necessary by making a copy 1478 */ 1479 void 1480 fdunshare(struct proc *p, struct thread *td) 1481 { 1482 1483 FILEDESC_LOCK_FAST(p->p_fd); 1484 if (p->p_fd->fd_refcnt > 1) { 1485 struct filedesc *tmp; 1486 1487 FILEDESC_UNLOCK_FAST(p->p_fd); 1488 tmp = fdcopy(p->p_fd); 1489 fdfree(td); 1490 p->p_fd = tmp; 1491 } else 1492 FILEDESC_UNLOCK_FAST(p->p_fd); 1493 } 1494 1495 /* 1496 * Copy a filedesc structure. 1497 * A NULL pointer in returns a NULL reference, this is to ease callers, 1498 * not catch errors. 1499 */ 1500 struct filedesc * 1501 fdcopy(struct filedesc *fdp) 1502 { 1503 struct filedesc *newfdp; 1504 int i; 1505 1506 /* Certain daemons might not have file descriptors. */ 1507 if (fdp == NULL) 1508 return (NULL); 1509 1510 newfdp = fdinit(fdp); 1511 FILEDESC_LOCK_FAST(fdp); 1512 while (fdp->fd_lastfile >= newfdp->fd_nfiles) { 1513 FILEDESC_UNLOCK_FAST(fdp); 1514 FILEDESC_LOCK(newfdp); 1515 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1516 FILEDESC_UNLOCK(newfdp); 1517 FILEDESC_LOCK_FAST(fdp); 1518 } 1519 /* copy everything except kqueue descriptors */ 1520 newfdp->fd_freefile = -1; 1521 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1522 if (fdisused(fdp, i) && 1523 fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE && 1524 (fdp->fd_ofileflags[i] & UF_OPENING) == 0) { 1525 newfdp->fd_ofiles[i] = fdp->fd_ofiles[i]; 1526 newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i]; 1527 fhold(newfdp->fd_ofiles[i]); 1528 newfdp->fd_lastfile = i; 1529 } else { 1530 if (newfdp->fd_freefile == -1) 1531 newfdp->fd_freefile = i; 1532 } 1533 } 1534 FILEDESC_UNLOCK_FAST(fdp); 1535 FILEDESC_LOCK(newfdp); 1536 for (i = 0; i <= newfdp->fd_lastfile; ++i) 1537 if (newfdp->fd_ofiles[i] != NULL) 1538 fdused(newfdp, i); 1539 FILEDESC_UNLOCK(newfdp); 1540 FILEDESC_LOCK_FAST(fdp); 1541 if (newfdp->fd_freefile == -1) 1542 newfdp->fd_freefile = i; 1543 newfdp->fd_cmask = fdp->fd_cmask; 1544 FILEDESC_UNLOCK_FAST(fdp); 1545 return (newfdp); 1546 } 1547 1548 /* 1549 * Release a filedesc structure. 1550 */ 1551 void 1552 fdfree(struct thread *td) 1553 { 1554 struct filedesc *fdp; 1555 struct file **fpp; 1556 int i, locked; 1557 struct filedesc_to_leader *fdtol; 1558 struct file *fp; 1559 struct vnode *cdir, *jdir, *rdir, *vp; 1560 struct flock lf; 1561 1562 /* Certain daemons might not have file descriptors. */ 1563 fdp = td->td_proc->p_fd; 1564 if (fdp == NULL) 1565 return; 1566 1567 /* Check for special need to clear POSIX style locks */ 1568 fdtol = td->td_proc->p_fdtol; 1569 if (fdtol != NULL) { 1570 FILEDESC_LOCK(fdp); 1571 KASSERT(fdtol->fdl_refcount > 0, 1572 ("filedesc_to_refcount botch: fdl_refcount=%d", 1573 fdtol->fdl_refcount)); 1574 if (fdtol->fdl_refcount == 1 && 1575 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1576 for (i = 0, fpp = fdp->fd_ofiles; 1577 i <= fdp->fd_lastfile; 1578 i++, fpp++) { 1579 if (*fpp == NULL || 1580 (*fpp)->f_type != DTYPE_VNODE) 1581 continue; 1582 fp = *fpp; 1583 fhold(fp); 1584 FILEDESC_UNLOCK(fdp); 1585 lf.l_whence = SEEK_SET; 1586 lf.l_start = 0; 1587 lf.l_len = 0; 1588 lf.l_type = F_UNLCK; 1589 vp = fp->f_vnode; 1590 locked = VFS_LOCK_GIANT(vp->v_mount); 1591 (void) VOP_ADVLOCK(vp, 1592 (caddr_t)td->td_proc-> 1593 p_leader, 1594 F_UNLCK, 1595 &lf, 1596 F_POSIX); 1597 VFS_UNLOCK_GIANT(locked); 1598 FILEDESC_LOCK(fdp); 1599 fdrop(fp, td); 1600 fpp = fdp->fd_ofiles + i; 1601 } 1602 } 1603 retry: 1604 if (fdtol->fdl_refcount == 1) { 1605 if (fdp->fd_holdleaderscount > 0 && 1606 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1607 /* 1608 * close() or do_dup() has cleared a reference 1609 * in a shared file descriptor table. 1610 */ 1611 fdp->fd_holdleaderswakeup = 1; 1612 msleep(&fdp->fd_holdleaderscount, &fdp->fd_mtx, 1613 PLOCK, "fdlhold", 0); 1614 goto retry; 1615 } 1616 if (fdtol->fdl_holdcount > 0) { 1617 /* 1618 * Ensure that fdtol->fdl_leader 1619 * remains valid in closef(). 1620 */ 1621 fdtol->fdl_wakeup = 1; 1622 msleep(fdtol, &fdp->fd_mtx, 1623 PLOCK, "fdlhold", 0); 1624 goto retry; 1625 } 1626 } 1627 fdtol->fdl_refcount--; 1628 if (fdtol->fdl_refcount == 0 && 1629 fdtol->fdl_holdcount == 0) { 1630 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1631 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1632 } else 1633 fdtol = NULL; 1634 td->td_proc->p_fdtol = NULL; 1635 FILEDESC_UNLOCK(fdp); 1636 if (fdtol != NULL) 1637 FREE(fdtol, M_FILEDESC_TO_LEADER); 1638 } 1639 FILEDESC_LOCK_FAST(fdp); 1640 i = --fdp->fd_refcnt; 1641 FILEDESC_UNLOCK_FAST(fdp); 1642 if (i > 0) 1643 return; 1644 /* 1645 * We are the last reference to the structure, so we can 1646 * safely assume it will not change out from under us. 1647 */ 1648 fpp = fdp->fd_ofiles; 1649 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) { 1650 if (*fpp) 1651 (void) closef(*fpp, td); 1652 } 1653 FILEDESC_LOCK(fdp); 1654 1655 /* XXX This should happen earlier. */ 1656 mtx_lock(&fdesc_mtx); 1657 td->td_proc->p_fd = NULL; 1658 mtx_unlock(&fdesc_mtx); 1659 1660 if (fdp->fd_nfiles > NDFILE) 1661 FREE(fdp->fd_ofiles, M_FILEDESC); 1662 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE)) 1663 FREE(fdp->fd_map, M_FILEDESC); 1664 1665 fdp->fd_nfiles = 0; 1666 1667 cdir = fdp->fd_cdir; 1668 fdp->fd_cdir = NULL; 1669 rdir = fdp->fd_rdir; 1670 fdp->fd_rdir = NULL; 1671 jdir = fdp->fd_jdir; 1672 fdp->fd_jdir = NULL; 1673 FILEDESC_UNLOCK(fdp); 1674 1675 if (cdir) { 1676 locked = VFS_LOCK_GIANT(cdir->v_mount); 1677 vrele(cdir); 1678 VFS_UNLOCK_GIANT(locked); 1679 } 1680 if (rdir) { 1681 locked = VFS_LOCK_GIANT(rdir->v_mount); 1682 vrele(rdir); 1683 VFS_UNLOCK_GIANT(locked); 1684 } 1685 if (jdir) { 1686 locked = VFS_LOCK_GIANT(jdir->v_mount); 1687 vrele(jdir); 1688 VFS_UNLOCK_GIANT(locked); 1689 } 1690 1691 fddrop(fdp); 1692 } 1693 1694 /* 1695 * For setugid programs, we don't want to people to use that setugidness 1696 * to generate error messages which write to a file which otherwise would 1697 * otherwise be off-limits to the process. We check for filesystems where 1698 * the vnode can change out from under us after execve (like [lin]procfs). 1699 * 1700 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 1701 * sufficient. We also don't check for setugidness since we know we are. 1702 */ 1703 static int 1704 is_unsafe(struct file *fp) 1705 { 1706 if (fp->f_type == DTYPE_VNODE) { 1707 struct vnode *vp = fp->f_vnode; 1708 1709 if ((vp->v_vflag & VV_PROCDEP) != 0) 1710 return (1); 1711 } 1712 return (0); 1713 } 1714 1715 /* 1716 * Make this setguid thing safe, if at all possible. 1717 */ 1718 void 1719 setugidsafety(struct thread *td) 1720 { 1721 struct filedesc *fdp; 1722 int i; 1723 1724 /* Certain daemons might not have file descriptors. */ 1725 fdp = td->td_proc->p_fd; 1726 if (fdp == NULL) 1727 return; 1728 1729 /* 1730 * Note: fdp->fd_ofiles may be reallocated out from under us while 1731 * we are blocked in a close. Be careful! 1732 */ 1733 FILEDESC_LOCK(fdp); 1734 for (i = 0; i <= fdp->fd_lastfile; i++) { 1735 if (i > 2) 1736 break; 1737 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) { 1738 struct file *fp; 1739 1740 knote_fdclose(td, i); 1741 /* 1742 * NULL-out descriptor prior to close to avoid 1743 * a race while close blocks. 1744 */ 1745 fp = fdp->fd_ofiles[i]; 1746 fdp->fd_ofiles[i] = NULL; 1747 fdp->fd_ofileflags[i] = 0; 1748 fdunused(fdp, i); 1749 FILEDESC_UNLOCK(fdp); 1750 (void) closef(fp, td); 1751 FILEDESC_LOCK(fdp); 1752 } 1753 } 1754 FILEDESC_UNLOCK(fdp); 1755 } 1756 1757 void 1758 fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td) 1759 { 1760 1761 FILEDESC_LOCK(fdp); 1762 if (fdp->fd_ofiles[idx] == fp) { 1763 fdp->fd_ofiles[idx] = NULL; 1764 fdunused(fdp, idx); 1765 FILEDESC_UNLOCK(fdp); 1766 fdrop(fp, td); 1767 } else { 1768 FILEDESC_UNLOCK(fdp); 1769 } 1770 } 1771 1772 /* 1773 * Close any files on exec? 1774 */ 1775 void 1776 fdcloseexec(struct thread *td) 1777 { 1778 struct filedesc *fdp; 1779 int i; 1780 1781 /* Certain daemons might not have file descriptors. */ 1782 fdp = td->td_proc->p_fd; 1783 if (fdp == NULL) 1784 return; 1785 1786 FILEDESC_LOCK(fdp); 1787 1788 /* 1789 * We cannot cache fd_ofiles or fd_ofileflags since operations 1790 * may block and rip them out from under us. 1791 */ 1792 for (i = 0; i <= fdp->fd_lastfile; i++) { 1793 if (fdp->fd_ofiles[i] != NULL && 1794 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) { 1795 struct file *fp; 1796 1797 knote_fdclose(td, i); 1798 /* 1799 * NULL-out descriptor prior to close to avoid 1800 * a race while close blocks. 1801 */ 1802 fp = fdp->fd_ofiles[i]; 1803 fdp->fd_ofiles[i] = NULL; 1804 fdp->fd_ofileflags[i] = 0; 1805 fdunused(fdp, i); 1806 FILEDESC_UNLOCK(fdp); 1807 (void) closef(fp, td); 1808 FILEDESC_LOCK(fdp); 1809 } 1810 } 1811 FILEDESC_UNLOCK(fdp); 1812 } 1813 1814 /* 1815 * It is unsafe for set[ug]id processes to be started with file 1816 * descriptors 0..2 closed, as these descriptors are given implicit 1817 * significance in the Standard C library. fdcheckstd() will create a 1818 * descriptor referencing /dev/null for each of stdin, stdout, and 1819 * stderr that is not already open. 1820 */ 1821 int 1822 fdcheckstd(struct thread *td) 1823 { 1824 struct filedesc *fdp; 1825 register_t retval, save; 1826 int i, error, devnull; 1827 1828 fdp = td->td_proc->p_fd; 1829 if (fdp == NULL) 1830 return (0); 1831 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 1832 devnull = -1; 1833 error = 0; 1834 for (i = 0; i < 3; i++) { 1835 if (fdp->fd_ofiles[i] != NULL) 1836 continue; 1837 if (devnull < 0) { 1838 save = td->td_retval[0]; 1839 error = kern_open(td, "/dev/null", UIO_SYSSPACE, 1840 O_RDWR, 0); 1841 devnull = td->td_retval[0]; 1842 KASSERT(devnull == i, ("oof, we didn't get our fd")); 1843 td->td_retval[0] = save; 1844 if (error) 1845 break; 1846 } else { 1847 error = do_dup(td, DUP_FIXED, devnull, i, &retval); 1848 if (error != 0) 1849 break; 1850 } 1851 } 1852 return (error); 1853 } 1854 1855 /* 1856 * Internal form of close. 1857 * Decrement reference count on file structure. 1858 * Note: td may be NULL when closing a file that was being passed in a 1859 * message. 1860 * 1861 * XXXRW: Giant is not required for the caller, but often will be held; this 1862 * makes it moderately likely the Giant will be recursed in the VFS case. 1863 */ 1864 int 1865 closef(struct file *fp, struct thread *td) 1866 { 1867 struct vnode *vp; 1868 struct flock lf; 1869 struct filedesc_to_leader *fdtol; 1870 struct filedesc *fdp; 1871 1872 /* 1873 * POSIX record locking dictates that any close releases ALL 1874 * locks owned by this process. This is handled by setting 1875 * a flag in the unlock to free ONLY locks obeying POSIX 1876 * semantics, and not to free BSD-style file locks. 1877 * If the descriptor was in a message, POSIX-style locks 1878 * aren't passed with the descriptor, and the thread pointer 1879 * will be NULL. Callers should be careful only to pass a 1880 * NULL thread pointer when there really is no owning 1881 * context that might have locks, or the locks will be 1882 * leaked. 1883 */ 1884 if (fp->f_type == DTYPE_VNODE && td != NULL) { 1885 int vfslocked; 1886 1887 vp = fp->f_vnode; 1888 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 1889 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1890 lf.l_whence = SEEK_SET; 1891 lf.l_start = 0; 1892 lf.l_len = 0; 1893 lf.l_type = F_UNLCK; 1894 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader, 1895 F_UNLCK, &lf, F_POSIX); 1896 } 1897 fdtol = td->td_proc->p_fdtol; 1898 if (fdtol != NULL) { 1899 /* 1900 * Handle special case where file descriptor table 1901 * is shared between multiple process leaders. 1902 */ 1903 fdp = td->td_proc->p_fd; 1904 FILEDESC_LOCK(fdp); 1905 for (fdtol = fdtol->fdl_next; 1906 fdtol != td->td_proc->p_fdtol; 1907 fdtol = fdtol->fdl_next) { 1908 if ((fdtol->fdl_leader->p_flag & 1909 P_ADVLOCK) == 0) 1910 continue; 1911 fdtol->fdl_holdcount++; 1912 FILEDESC_UNLOCK(fdp); 1913 lf.l_whence = SEEK_SET; 1914 lf.l_start = 0; 1915 lf.l_len = 0; 1916 lf.l_type = F_UNLCK; 1917 vp = fp->f_vnode; 1918 (void) VOP_ADVLOCK(vp, 1919 (caddr_t)fdtol->fdl_leader, 1920 F_UNLCK, &lf, F_POSIX); 1921 FILEDESC_LOCK(fdp); 1922 fdtol->fdl_holdcount--; 1923 if (fdtol->fdl_holdcount == 0 && 1924 fdtol->fdl_wakeup != 0) { 1925 fdtol->fdl_wakeup = 0; 1926 wakeup(fdtol); 1927 } 1928 } 1929 FILEDESC_UNLOCK(fdp); 1930 } 1931 VFS_UNLOCK_GIANT(vfslocked); 1932 } 1933 return (fdrop(fp, td)); 1934 } 1935 1936 /* 1937 * Extract the file pointer associated with the specified descriptor for 1938 * the current user process. 1939 * 1940 * If the descriptor doesn't exist, EBADF is returned. 1941 * 1942 * If the descriptor exists but doesn't match 'flags' then 1943 * return EBADF for read attempts and EINVAL for write attempts. 1944 * 1945 * If 'hold' is set (non-zero) the file's refcount will be bumped on return. 1946 * It should be dropped with fdrop(). 1947 * If it is not set, then the refcount will not be bumped however the 1948 * thread's filedesc struct will be returned locked (for fgetsock). 1949 * 1950 * If an error occured the non-zero error is returned and *fpp is set to NULL. 1951 * Otherwise *fpp is set and zero is returned. 1952 */ 1953 static __inline int 1954 _fget(struct thread *td, int fd, struct file **fpp, int flags, int hold) 1955 { 1956 struct filedesc *fdp; 1957 struct file *fp; 1958 1959 *fpp = NULL; 1960 if (td == NULL || (fdp = td->td_proc->p_fd) == NULL) 1961 return (EBADF); 1962 FILEDESC_LOCK(fdp); 1963 if ((fp = fget_locked(fdp, fd)) == NULL || fp->f_ops == &badfileops) { 1964 FILEDESC_UNLOCK(fdp); 1965 return (EBADF); 1966 } 1967 1968 /* 1969 * Note: FREAD failure returns EBADF to maintain backwards 1970 * compatibility with what routines returned before. 1971 * 1972 * Only one flag, or 0, may be specified. 1973 */ 1974 if (flags == FREAD && (fp->f_flag & FREAD) == 0) { 1975 FILEDESC_UNLOCK(fdp); 1976 return (EBADF); 1977 } 1978 if (flags == FWRITE && (fp->f_flag & FWRITE) == 0) { 1979 FILEDESC_UNLOCK(fdp); 1980 return (EINVAL); 1981 } 1982 if (hold) { 1983 fhold(fp); 1984 FILEDESC_UNLOCK(fdp); 1985 } 1986 *fpp = fp; 1987 return (0); 1988 } 1989 1990 int 1991 fget(struct thread *td, int fd, struct file **fpp) 1992 { 1993 1994 return(_fget(td, fd, fpp, 0, 1)); 1995 } 1996 1997 int 1998 fget_read(struct thread *td, int fd, struct file **fpp) 1999 { 2000 2001 return(_fget(td, fd, fpp, FREAD, 1)); 2002 } 2003 2004 int 2005 fget_write(struct thread *td, int fd, struct file **fpp) 2006 { 2007 2008 return(_fget(td, fd, fpp, FWRITE, 1)); 2009 } 2010 2011 /* 2012 * Like fget() but loads the underlying vnode, or returns an error if 2013 * the descriptor does not represent a vnode. Note that pipes use vnodes 2014 * but never have VM objects. The returned vnode will be vref()d. 2015 * 2016 * XXX: what about the unused flags ? 2017 */ 2018 static __inline int 2019 _fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags) 2020 { 2021 struct file *fp; 2022 int error; 2023 2024 *vpp = NULL; 2025 if ((error = _fget(td, fd, &fp, flags, 0)) != 0) 2026 return (error); 2027 if (fp->f_vnode == NULL) { 2028 error = EINVAL; 2029 } else { 2030 *vpp = fp->f_vnode; 2031 vref(*vpp); 2032 } 2033 FILEDESC_UNLOCK(td->td_proc->p_fd); 2034 return (error); 2035 } 2036 2037 int 2038 fgetvp(struct thread *td, int fd, struct vnode **vpp) 2039 { 2040 2041 return (_fgetvp(td, fd, vpp, 0)); 2042 } 2043 2044 int 2045 fgetvp_read(struct thread *td, int fd, struct vnode **vpp) 2046 { 2047 2048 return (_fgetvp(td, fd, vpp, FREAD)); 2049 } 2050 2051 #ifdef notyet 2052 int 2053 fgetvp_write(struct thread *td, int fd, struct vnode **vpp) 2054 { 2055 2056 return (_fgetvp(td, fd, vpp, FWRITE)); 2057 } 2058 #endif 2059 2060 /* 2061 * Like fget() but loads the underlying socket, or returns an error if 2062 * the descriptor does not represent a socket. 2063 * 2064 * We bump the ref count on the returned socket. XXX Also obtain the SX 2065 * lock in the future. 2066 */ 2067 int 2068 fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp) 2069 { 2070 struct file *fp; 2071 int error; 2072 2073 NET_ASSERT_GIANT(); 2074 2075 *spp = NULL; 2076 if (fflagp != NULL) 2077 *fflagp = 0; 2078 if ((error = _fget(td, fd, &fp, 0, 0)) != 0) 2079 return (error); 2080 if (fp->f_type != DTYPE_SOCKET) { 2081 error = ENOTSOCK; 2082 } else { 2083 *spp = fp->f_data; 2084 if (fflagp) 2085 *fflagp = fp->f_flag; 2086 SOCK_LOCK(*spp); 2087 soref(*spp); 2088 SOCK_UNLOCK(*spp); 2089 } 2090 FILEDESC_UNLOCK(td->td_proc->p_fd); 2091 return (error); 2092 } 2093 2094 /* 2095 * Drop the reference count on the socket and XXX release the SX lock in 2096 * the future. The last reference closes the socket. 2097 */ 2098 void 2099 fputsock(struct socket *so) 2100 { 2101 2102 NET_ASSERT_GIANT(); 2103 ACCEPT_LOCK(); 2104 SOCK_LOCK(so); 2105 sorele(so); 2106 } 2107 2108 int 2109 fdrop(struct file *fp, struct thread *td) 2110 { 2111 2112 FILE_LOCK(fp); 2113 return (fdrop_locked(fp, td)); 2114 } 2115 2116 /* 2117 * Drop reference on struct file passed in, may call closef if the 2118 * reference hits zero. 2119 * Expects struct file locked, and will unlock it. 2120 */ 2121 static int 2122 fdrop_locked(struct file *fp, struct thread *td) 2123 { 2124 int error; 2125 2126 FILE_LOCK_ASSERT(fp, MA_OWNED); 2127 2128 if (--fp->f_count > 0) { 2129 FILE_UNLOCK(fp); 2130 return (0); 2131 } 2132 2133 /* 2134 * We might have just dropped the last reference to a file 2135 * object that is for a UNIX domain socket whose message 2136 * buffers are being examined in unp_gc(). If that is the 2137 * case, FWAIT will be set in f_gcflag and we need to wait for 2138 * unp_gc() to finish its scan. 2139 */ 2140 while (fp->f_gcflag & FWAIT) 2141 msleep(&fp->f_gcflag, fp->f_mtxp, 0, "fpdrop", 0); 2142 2143 /* We have the last ref so we can proceed without the file lock. */ 2144 FILE_UNLOCK(fp); 2145 if (fp->f_count < 0) 2146 panic("fdrop: count < 0"); 2147 if (fp->f_ops != &badfileops) 2148 error = fo_close(fp, td); 2149 else 2150 error = 0; 2151 2152 sx_xlock(&filelist_lock); 2153 LIST_REMOVE(fp, f_list); 2154 openfiles--; 2155 sx_xunlock(&filelist_lock); 2156 crfree(fp->f_cred); 2157 uma_zfree(file_zone, fp); 2158 2159 return (error); 2160 } 2161 2162 /* 2163 * Apply an advisory lock on a file descriptor. 2164 * 2165 * Just attempt to get a record lock of the requested type on 2166 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2167 */ 2168 #ifndef _SYS_SYSPROTO_H_ 2169 struct flock_args { 2170 int fd; 2171 int how; 2172 }; 2173 #endif 2174 /* 2175 * MPSAFE 2176 */ 2177 /* ARGSUSED */ 2178 int 2179 flock(struct thread *td, struct flock_args *uap) 2180 { 2181 struct file *fp; 2182 struct vnode *vp; 2183 struct flock lf; 2184 int error; 2185 2186 if ((error = fget(td, uap->fd, &fp)) != 0) 2187 return (error); 2188 if (fp->f_type != DTYPE_VNODE) { 2189 fdrop(fp, td); 2190 return (EOPNOTSUPP); 2191 } 2192 2193 mtx_lock(&Giant); 2194 vp = fp->f_vnode; 2195 lf.l_whence = SEEK_SET; 2196 lf.l_start = 0; 2197 lf.l_len = 0; 2198 if (uap->how & LOCK_UN) { 2199 lf.l_type = F_UNLCK; 2200 FILE_LOCK(fp); 2201 fp->f_flag &= ~FHASLOCK; 2202 FILE_UNLOCK(fp); 2203 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 2204 goto done2; 2205 } 2206 if (uap->how & LOCK_EX) 2207 lf.l_type = F_WRLCK; 2208 else if (uap->how & LOCK_SH) 2209 lf.l_type = F_RDLCK; 2210 else { 2211 error = EBADF; 2212 goto done2; 2213 } 2214 FILE_LOCK(fp); 2215 fp->f_flag |= FHASLOCK; 2216 FILE_UNLOCK(fp); 2217 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 2218 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT); 2219 done2: 2220 fdrop(fp, td); 2221 mtx_unlock(&Giant); 2222 return (error); 2223 } 2224 /* 2225 * Duplicate the specified descriptor to a free descriptor. 2226 */ 2227 int 2228 dupfdopen(struct thread *td, struct filedesc *fdp, int indx, int dfd, int mode, int error) 2229 { 2230 struct file *wfp; 2231 struct file *fp; 2232 2233 /* 2234 * If the to-be-dup'd fd number is greater than the allowed number 2235 * of file descriptors, or the fd to be dup'd has already been 2236 * closed, then reject. 2237 */ 2238 FILEDESC_LOCK(fdp); 2239 if (dfd < 0 || dfd >= fdp->fd_nfiles || 2240 (wfp = fdp->fd_ofiles[dfd]) == NULL) { 2241 FILEDESC_UNLOCK(fdp); 2242 return (EBADF); 2243 } 2244 2245 /* 2246 * There are two cases of interest here. 2247 * 2248 * For ENODEV simply dup (dfd) to file descriptor 2249 * (indx) and return. 2250 * 2251 * For ENXIO steal away the file structure from (dfd) and 2252 * store it in (indx). (dfd) is effectively closed by 2253 * this operation. 2254 * 2255 * Any other error code is just returned. 2256 */ 2257 switch (error) { 2258 case ENODEV: 2259 /* 2260 * Check that the mode the file is being opened for is a 2261 * subset of the mode of the existing descriptor. 2262 */ 2263 FILE_LOCK(wfp); 2264 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2265 FILE_UNLOCK(wfp); 2266 FILEDESC_UNLOCK(fdp); 2267 return (EACCES); 2268 } 2269 fp = fdp->fd_ofiles[indx]; 2270 fdp->fd_ofiles[indx] = wfp; 2271 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2272 if (fp == NULL) 2273 fdused(fdp, indx); 2274 fhold_locked(wfp); 2275 FILE_UNLOCK(wfp); 2276 FILEDESC_UNLOCK(fdp); 2277 if (fp != NULL) { 2278 /* 2279 * We now own the reference to fp that the ofiles[] 2280 * array used to own. Release it. 2281 */ 2282 FILE_LOCK(fp); 2283 fdrop_locked(fp, td); 2284 } 2285 return (0); 2286 2287 case ENXIO: 2288 /* 2289 * Steal away the file pointer from dfd and stuff it into indx. 2290 */ 2291 fp = fdp->fd_ofiles[indx]; 2292 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd]; 2293 fdp->fd_ofiles[dfd] = NULL; 2294 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2295 fdp->fd_ofileflags[dfd] = 0; 2296 fdunused(fdp, dfd); 2297 if (fp == NULL) 2298 fdused(fdp, indx); 2299 if (fp != NULL) 2300 FILE_LOCK(fp); 2301 2302 /* 2303 * We now own the reference to fp that the ofiles[] array 2304 * used to own. Release it. 2305 */ 2306 if (fp != NULL) 2307 fdrop_locked(fp, td); 2308 2309 FILEDESC_UNLOCK(fdp); 2310 2311 return (0); 2312 2313 default: 2314 FILEDESC_UNLOCK(fdp); 2315 return (error); 2316 } 2317 /* NOTREACHED */ 2318 } 2319 2320 /* 2321 * Scan all active processes to see if any of them have a current 2322 * or root directory of `olddp'. If so, replace them with the new 2323 * mount point. 2324 */ 2325 void 2326 mountcheckdirs(struct vnode *olddp, struct vnode *newdp) 2327 { 2328 struct filedesc *fdp; 2329 struct proc *p; 2330 int nrele; 2331 2332 if (vrefcnt(olddp) == 1) 2333 return; 2334 sx_slock(&allproc_lock); 2335 LIST_FOREACH(p, &allproc, p_list) { 2336 fdp = fdhold(p); 2337 if (fdp == NULL) 2338 continue; 2339 nrele = 0; 2340 FILEDESC_LOCK_FAST(fdp); 2341 if (fdp->fd_cdir == olddp) { 2342 vref(newdp); 2343 fdp->fd_cdir = newdp; 2344 nrele++; 2345 } 2346 if (fdp->fd_rdir == olddp) { 2347 vref(newdp); 2348 fdp->fd_rdir = newdp; 2349 nrele++; 2350 } 2351 FILEDESC_UNLOCK_FAST(fdp); 2352 fddrop(fdp); 2353 while (nrele--) 2354 vrele(olddp); 2355 } 2356 sx_sunlock(&allproc_lock); 2357 if (rootvnode == olddp) { 2358 vrele(rootvnode); 2359 vref(newdp); 2360 rootvnode = newdp; 2361 } 2362 } 2363 2364 struct filedesc_to_leader * 2365 filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader) 2366 { 2367 struct filedesc_to_leader *fdtol; 2368 2369 MALLOC(fdtol, struct filedesc_to_leader *, 2370 sizeof(struct filedesc_to_leader), 2371 M_FILEDESC_TO_LEADER, 2372 M_WAITOK); 2373 fdtol->fdl_refcount = 1; 2374 fdtol->fdl_holdcount = 0; 2375 fdtol->fdl_wakeup = 0; 2376 fdtol->fdl_leader = leader; 2377 if (old != NULL) { 2378 FILEDESC_LOCK(fdp); 2379 fdtol->fdl_next = old->fdl_next; 2380 fdtol->fdl_prev = old; 2381 old->fdl_next = fdtol; 2382 fdtol->fdl_next->fdl_prev = fdtol; 2383 FILEDESC_UNLOCK(fdp); 2384 } else { 2385 fdtol->fdl_next = fdtol; 2386 fdtol->fdl_prev = fdtol; 2387 } 2388 return (fdtol); 2389 } 2390 2391 /* 2392 * Get file structures. 2393 */ 2394 static int 2395 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2396 { 2397 struct xfile xf; 2398 struct filedesc *fdp; 2399 struct file *fp; 2400 struct proc *p; 2401 int error, n; 2402 2403 /* 2404 * Note: because the number of file descriptors is calculated 2405 * in different ways for sizing vs returning the data, 2406 * there is information leakage from the first loop. However, 2407 * it is of a similar order of magnitude to the leakage from 2408 * global system statistics such as kern.openfiles. 2409 */ 2410 error = sysctl_wire_old_buffer(req, 0); 2411 if (error != 0) 2412 return (error); 2413 if (req->oldptr == NULL) { 2414 n = 16; /* A slight overestimate. */ 2415 sx_slock(&filelist_lock); 2416 LIST_FOREACH(fp, &filehead, f_list) { 2417 /* 2418 * We should grab the lock, but this is an 2419 * estimate, so does it really matter? 2420 */ 2421 /* mtx_lock(fp->f_mtxp); */ 2422 n += fp->f_count; 2423 /* mtx_unlock(f->f_mtxp); */ 2424 } 2425 sx_sunlock(&filelist_lock); 2426 return (SYSCTL_OUT(req, 0, n * sizeof(xf))); 2427 } 2428 error = 0; 2429 bzero(&xf, sizeof(xf)); 2430 xf.xf_size = sizeof(xf); 2431 sx_slock(&allproc_lock); 2432 LIST_FOREACH(p, &allproc, p_list) { 2433 if (p->p_state == PRS_NEW) 2434 continue; 2435 PROC_LOCK(p); 2436 if (p_cansee(req->td, p) != 0) { 2437 PROC_UNLOCK(p); 2438 continue; 2439 } 2440 xf.xf_pid = p->p_pid; 2441 xf.xf_uid = p->p_ucred->cr_uid; 2442 PROC_UNLOCK(p); 2443 fdp = fdhold(p); 2444 if (fdp == NULL) 2445 continue; 2446 FILEDESC_LOCK_FAST(fdp); 2447 for (n = 0; fdp->fd_refcnt > 0 && n < fdp->fd_nfiles; ++n) { 2448 if ((fp = fdp->fd_ofiles[n]) == NULL) 2449 continue; 2450 xf.xf_fd = n; 2451 xf.xf_file = fp; 2452 xf.xf_data = fp->f_data; 2453 xf.xf_vnode = fp->f_vnode; 2454 xf.xf_type = fp->f_type; 2455 xf.xf_count = fp->f_count; 2456 xf.xf_msgcount = fp->f_msgcount; 2457 xf.xf_offset = fp->f_offset; 2458 xf.xf_flag = fp->f_flag; 2459 error = SYSCTL_OUT(req, &xf, sizeof(xf)); 2460 if (error) 2461 break; 2462 } 2463 FILEDESC_UNLOCK_FAST(fdp); 2464 fddrop(fdp); 2465 if (error) 2466 break; 2467 } 2468 sx_sunlock(&allproc_lock); 2469 return (error); 2470 } 2471 2472 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2473 0, 0, sysctl_kern_file, "S,xfile", "Entire file table"); 2474 2475 #ifdef DDB 2476 /* 2477 * For the purposes of debugging, generate a human-readable string for the 2478 * file type. 2479 */ 2480 static const char * 2481 file_type_to_name(short type) 2482 { 2483 2484 switch (type) { 2485 case 0: 2486 return ("zero"); 2487 case DTYPE_VNODE: 2488 return ("vnod"); 2489 case DTYPE_SOCKET: 2490 return ("sock"); 2491 case DTYPE_PIPE: 2492 return ("pipe"); 2493 case DTYPE_FIFO: 2494 return ("fifo"); 2495 case DTYPE_CRYPTO: 2496 return ("crpt"); 2497 default: 2498 return ("unkn"); 2499 } 2500 } 2501 2502 /* 2503 * For the purposes of debugging, identify a process (if any, perhaps one of 2504 * many) that references the passed file in its file descriptor array. Return 2505 * NULL if none. 2506 */ 2507 static struct proc * 2508 file_to_first_proc(struct file *fp) 2509 { 2510 struct filedesc *fdp; 2511 struct proc *p; 2512 int n; 2513 2514 LIST_FOREACH(p, &allproc, p_list) { 2515 if (p->p_state == PRS_NEW) 2516 continue; 2517 fdp = p->p_fd; 2518 if (fdp == NULL) 2519 continue; 2520 for (n = 0; n < fdp->fd_nfiles; n++) { 2521 if (fp == fdp->fd_ofiles[n]) 2522 return (p); 2523 } 2524 } 2525 return (NULL); 2526 } 2527 2528 DB_SHOW_COMMAND(files, db_show_files) 2529 { 2530 struct file *fp; 2531 struct proc *p; 2532 2533 db_printf("%8s %4s %8s %8s %4s %5s %6s %8s %5s %12s\n", "File", 2534 "Type", "Data", "Flag", "GCFl", "Count", "MCount", "Vnode", 2535 "FPID", "FCmd"); 2536 LIST_FOREACH(fp, &filehead, f_list) { 2537 p = file_to_first_proc(fp); 2538 db_printf("%8p %4s %8p %08x %04x %5d %6d %8p %5d %12s\n", fp, 2539 file_type_to_name(fp->f_type), fp->f_data, fp->f_flag, 2540 fp->f_gcflag, fp->f_count, fp->f_msgcount, fp->f_vnode, 2541 p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-"); 2542 } 2543 } 2544 #endif 2545 2546 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 2547 &maxfilesperproc, 0, "Maximum files allowed open per process"); 2548 2549 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 2550 &maxfiles, 0, "Maximum number of files"); 2551 2552 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 2553 &openfiles, 0, "System-wide number of open files"); 2554 2555 /* ARGSUSED*/ 2556 static void 2557 filelistinit(void *dummy) 2558 { 2559 2560 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL, 2561 NULL, NULL, UMA_ALIGN_PTR, 0); 2562 sx_init(&filelist_lock, "filelist lock"); 2563 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF); 2564 mtx_init(&fdesc_mtx, "fdesc", NULL, MTX_DEF); 2565 } 2566 SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL) 2567 2568 /*-------------------------------------------------------------------*/ 2569 2570 static int 2571 badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td) 2572 { 2573 2574 return (EBADF); 2575 } 2576 2577 static int 2578 badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, struct thread *td) 2579 { 2580 2581 return (EBADF); 2582 } 2583 2584 static int 2585 badfo_poll(struct file *fp, int events, struct ucred *active_cred, struct thread *td) 2586 { 2587 2588 return (0); 2589 } 2590 2591 static int 2592 badfo_kqfilter(struct file *fp, struct knote *kn) 2593 { 2594 2595 return (EBADF); 2596 } 2597 2598 static int 2599 badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, struct thread *td) 2600 { 2601 2602 return (EBADF); 2603 } 2604 2605 static int 2606 badfo_close(struct file *fp, struct thread *td) 2607 { 2608 2609 return (EBADF); 2610 } 2611 2612 struct fileops badfileops = { 2613 .fo_read = badfo_readwrite, 2614 .fo_write = badfo_readwrite, 2615 .fo_ioctl = badfo_ioctl, 2616 .fo_poll = badfo_poll, 2617 .fo_kqfilter = badfo_kqfilter, 2618 .fo_stat = badfo_stat, 2619 .fo_close = badfo_close, 2620 }; 2621 2622 2623 /*-------------------------------------------------------------------*/ 2624 2625 /* 2626 * File Descriptor pseudo-device driver (/dev/fd/). 2627 * 2628 * Opening minor device N dup()s the file (if any) connected to file 2629 * descriptor N belonging to the calling process. Note that this driver 2630 * consists of only the ``open()'' routine, because all subsequent 2631 * references to this file will be direct to the other driver. 2632 * 2633 * XXX: we could give this one a cloning event handler if necessary. 2634 */ 2635 2636 /* ARGSUSED */ 2637 static int 2638 fdopen(struct cdev *dev, int mode, int type, struct thread *td) 2639 { 2640 2641 /* 2642 * XXX Kludge: set curthread->td_dupfd to contain the value of the 2643 * the file descriptor being sought for duplication. The error 2644 * return ensures that the vnode for this device will be released 2645 * by vn_open. Open will detect this special error and take the 2646 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 2647 * will simply report the error. 2648 */ 2649 td->td_dupfd = dev2unit(dev); 2650 return (ENODEV); 2651 } 2652 2653 static struct cdevsw fildesc_cdevsw = { 2654 .d_version = D_VERSION, 2655 .d_flags = D_NEEDGIANT, 2656 .d_open = fdopen, 2657 .d_name = "FD", 2658 }; 2659 2660 static void 2661 fildesc_drvinit(void *unused) 2662 { 2663 struct cdev *dev; 2664 2665 dev = make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "fd/0"); 2666 make_dev_alias(dev, "stdin"); 2667 dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1"); 2668 make_dev_alias(dev, "stdout"); 2669 dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2"); 2670 make_dev_alias(dev, "stderr"); 2671 } 2672 2673 SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL)
Cache object: 2e9606e602b3121508f5564229981d76
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