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/5.4/sys/kern/kern_descrip.c 145335 2005-04-20 19:11:07Z cvs2svn $"); 39 40 #include "opt_compat.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 45 #include <sys/conf.h> 46 #include <sys/fcntl.h> 47 #include <sys/file.h> 48 #include <sys/filedesc.h> 49 #include <sys/filio.h> 50 #include <sys/jail.h> 51 #include <sys/kernel.h> 52 #include <sys/limits.h> 53 #include <sys/lock.h> 54 #include <sys/malloc.h> 55 #include <sys/mount.h> 56 #include <sys/mutex.h> 57 #include <sys/namei.h> 58 #include <sys/proc.h> 59 #include <sys/resourcevar.h> 60 #include <sys/signalvar.h> 61 #include <sys/socketvar.h> 62 #include <sys/stat.h> 63 #include <sys/sx.h> 64 #include <sys/syscallsubr.h> 65 #include <sys/sysctl.h> 66 #include <sys/sysproto.h> 67 #include <sys/unistd.h> 68 #include <sys/vnode.h> 69 70 #include <vm/uma.h> 71 72 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 73 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 74 "file desc to leader structures"); 75 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 76 77 static uma_zone_t file_zone; 78 79 80 /* How to treat 'new' parameter when allocating a fd for do_dup(). */ 81 enum dup_type { DUP_VARIABLE, DUP_FIXED }; 82 83 static int do_dup(struct thread *td, enum dup_type type, int old, int new, 84 register_t *retval); 85 static int fd_first_free(struct filedesc *, int, int); 86 static int fd_last_used(struct filedesc *, int, int); 87 static void fdgrowtable(struct filedesc *, int); 88 static int fdrop_locked(struct file *fp, struct thread *td); 89 static void fdunused(struct filedesc *fdp, int fd); 90 static void fdused(struct filedesc *fdp, int fd); 91 92 /* 93 * A process is initially started out with NDFILE descriptors stored within 94 * this structure, selected to be enough for typical applications based on 95 * the historical limit of 20 open files (and the usage of descriptors by 96 * shells). If these descriptors are exhausted, a larger descriptor table 97 * may be allocated, up to a process' resource limit; the internal arrays 98 * are then unused. 99 */ 100 #define NDFILE 20 101 #define NDSLOTSIZE sizeof(NDSLOTTYPE) 102 #define NDENTRIES (NDSLOTSIZE * __CHAR_BIT) 103 #define NDSLOT(x) ((x) / NDENTRIES) 104 #define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES)) 105 #define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES) 106 107 /* 108 * Storage required per open file descriptor. 109 */ 110 #define OFILESIZE (sizeof(struct file *) + sizeof(char)) 111 112 /* 113 * Basic allocation of descriptors: 114 * one of the above, plus arrays for NDFILE descriptors. 115 */ 116 struct filedesc0 { 117 struct filedesc fd_fd; 118 /* 119 * These arrays are used when the number of open files is 120 * <= NDFILE, and are then pointed to by the pointers above. 121 */ 122 struct file *fd_dfiles[NDFILE]; 123 char fd_dfileflags[NDFILE]; 124 NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)]; 125 }; 126 127 /* 128 * Descriptor management. 129 */ 130 struct filelist filehead; /* head of list of open files */ 131 int nfiles; /* actual number of open files */ 132 struct sx filelist_lock; /* sx to protect filelist */ 133 struct mtx sigio_lock; /* mtx to protect pointers to sigio */ 134 135 /* A mutex to protect the association between a proc and filedesc. */ 136 static struct mtx fdesc_mtx; 137 138 /* 139 * Find the first zero bit in the given bitmap, starting at low and not 140 * exceeding size - 1. 141 */ 142 static int 143 fd_first_free(struct filedesc *fdp, int low, int size) 144 { 145 NDSLOTTYPE *map = fdp->fd_map; 146 NDSLOTTYPE mask; 147 int off, maxoff; 148 149 if (low >= size) 150 return (low); 151 152 off = NDSLOT(low); 153 if (low % NDENTRIES) { 154 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES))); 155 if ((mask &= ~map[off]) != 0UL) 156 return (off * NDENTRIES + ffsl(mask) - 1); 157 ++off; 158 } 159 for (maxoff = NDSLOTS(size); off < maxoff; ++off) 160 if (map[off] != ~0UL) 161 return (off * NDENTRIES + ffsl(~map[off]) - 1); 162 return (size); 163 } 164 165 /* 166 * Find the highest non-zero bit in the given bitmap, starting at low and 167 * not exceeding size - 1. 168 */ 169 static int 170 fd_last_used(struct filedesc *fdp, int low, int size) 171 { 172 NDSLOTTYPE *map = fdp->fd_map; 173 NDSLOTTYPE mask; 174 int off, minoff; 175 176 if (low >= size) 177 return (-1); 178 179 off = NDSLOT(size); 180 if (size % NDENTRIES) { 181 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES)); 182 if ((mask &= map[off]) != 0) 183 return (off * NDENTRIES + flsl(mask) - 1); 184 --off; 185 } 186 for (minoff = NDSLOT(low); off >= minoff; --off) 187 if (map[off] != 0) 188 return (off * NDENTRIES + flsl(map[off]) - 1); 189 return (size - 1); 190 } 191 192 static int 193 fdisused(struct filedesc *fdp, int fd) 194 { 195 KASSERT(fd >= 0 && fd < fdp->fd_nfiles, 196 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles)); 197 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0); 198 } 199 200 /* 201 * Mark a file descriptor as used. 202 */ 203 static void 204 fdused(struct filedesc *fdp, int fd) 205 { 206 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 207 KASSERT(!fdisused(fdp, fd), 208 ("fd already used")); 209 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd); 210 if (fd > fdp->fd_lastfile) 211 fdp->fd_lastfile = fd; 212 if (fd == fdp->fd_freefile) 213 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 214 } 215 216 /* 217 * Mark a file descriptor as unused. 218 */ 219 static void 220 fdunused(struct filedesc *fdp, int fd) 221 { 222 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 223 KASSERT(fdisused(fdp, fd), 224 ("fd is already unused")); 225 KASSERT(fdp->fd_ofiles[fd] == NULL, 226 ("fd is still in use")); 227 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd); 228 if (fd < fdp->fd_freefile) 229 fdp->fd_freefile = fd; 230 if (fd == fdp->fd_lastfile) 231 fdp->fd_lastfile = fd_last_used(fdp, 0, fd); 232 } 233 234 /* 235 * System calls on descriptors. 236 */ 237 #ifndef _SYS_SYSPROTO_H_ 238 struct getdtablesize_args { 239 int dummy; 240 }; 241 #endif 242 /* 243 * MPSAFE 244 */ 245 /* ARGSUSED */ 246 int 247 getdtablesize(struct thread *td, struct getdtablesize_args *uap) 248 { 249 struct proc *p = td->td_proc; 250 251 PROC_LOCK(p); 252 td->td_retval[0] = 253 min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 254 PROC_UNLOCK(p); 255 return (0); 256 } 257 258 /* 259 * Duplicate a file descriptor to a particular value. 260 * 261 * note: keep in mind that a potential race condition exists when closing 262 * descriptors from a shared descriptor table (via rfork). 263 */ 264 #ifndef _SYS_SYSPROTO_H_ 265 struct dup2_args { 266 u_int from; 267 u_int to; 268 }; 269 #endif 270 /* 271 * MPSAFE 272 */ 273 /* ARGSUSED */ 274 int 275 dup2(struct thread *td, struct dup2_args *uap) 276 { 277 278 return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to, 279 td->td_retval)); 280 } 281 282 /* 283 * Duplicate a file descriptor. 284 */ 285 #ifndef _SYS_SYSPROTO_H_ 286 struct dup_args { 287 u_int fd; 288 }; 289 #endif 290 /* 291 * MPSAFE 292 */ 293 /* ARGSUSED */ 294 int 295 dup(struct thread *td, struct dup_args *uap) 296 { 297 298 return (do_dup(td, DUP_VARIABLE, (int)uap->fd, 0, td->td_retval)); 299 } 300 301 /* 302 * The file control system call. 303 */ 304 #ifndef _SYS_SYSPROTO_H_ 305 struct fcntl_args { 306 int fd; 307 int cmd; 308 long arg; 309 }; 310 #endif 311 /* 312 * MPSAFE 313 */ 314 /* ARGSUSED */ 315 int 316 fcntl(struct thread *td, struct fcntl_args *uap) 317 { 318 struct flock fl; 319 intptr_t arg; 320 int error; 321 322 error = 0; 323 switch (uap->cmd) { 324 case F_GETLK: 325 case F_SETLK: 326 case F_SETLKW: 327 error = copyin((void *)(intptr_t)uap->arg, &fl, sizeof(fl)); 328 arg = (intptr_t)&fl; 329 break; 330 default: 331 arg = uap->arg; 332 break; 333 } 334 if (error) 335 return (error); 336 error = kern_fcntl(td, uap->fd, uap->cmd, arg); 337 if (error) 338 return (error); 339 if (uap->cmd == F_GETLK) 340 error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl)); 341 return (error); 342 } 343 344 int 345 kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) 346 { 347 struct filedesc *fdp; 348 struct flock *flp; 349 struct file *fp; 350 struct proc *p; 351 char *pop; 352 struct vnode *vp; 353 u_int newmin; 354 int error, flg, tmp; 355 int giant_locked; 356 357 /* 358 * XXXRW: Some fcntl() calls require Giant -- others don't. Try to 359 * avoid grabbing Giant for calls we know don't need it. 360 */ 361 switch (cmd) { 362 case F_DUPFD: 363 case F_GETFD: 364 case F_SETFD: 365 case F_GETFL: 366 giant_locked = 0; 367 break; 368 369 default: 370 giant_locked = 1; 371 mtx_lock(&Giant); 372 } 373 374 error = 0; 375 flg = F_POSIX; 376 p = td->td_proc; 377 fdp = p->p_fd; 378 FILEDESC_LOCK(fdp); 379 if ((unsigned)fd >= fdp->fd_nfiles || 380 (fp = fdp->fd_ofiles[fd]) == NULL) { 381 FILEDESC_UNLOCK(fdp); 382 error = EBADF; 383 goto done2; 384 } 385 pop = &fdp->fd_ofileflags[fd]; 386 387 switch (cmd) { 388 case F_DUPFD: 389 /* mtx_assert(&Giant, MA_NOTOWNED); */ 390 FILEDESC_UNLOCK(fdp); 391 newmin = arg; 392 PROC_LOCK(p); 393 if (newmin >= lim_cur(p, RLIMIT_NOFILE) || 394 newmin >= maxfilesperproc) { 395 PROC_UNLOCK(p); 396 error = EINVAL; 397 break; 398 } 399 PROC_UNLOCK(p); 400 error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval); 401 break; 402 403 case F_GETFD: 404 /* mtx_assert(&Giant, MA_NOTOWNED); */ 405 td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0; 406 FILEDESC_UNLOCK(fdp); 407 break; 408 409 case F_SETFD: 410 /* mtx_assert(&Giant, MA_NOTOWNED); */ 411 *pop = (*pop &~ UF_EXCLOSE) | 412 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0); 413 FILEDESC_UNLOCK(fdp); 414 break; 415 416 case F_GETFL: 417 /* mtx_assert(&Giant, MA_NOTOWNED); */ 418 FILE_LOCK(fp); 419 td->td_retval[0] = OFLAGS(fp->f_flag); 420 FILE_UNLOCK(fp); 421 FILEDESC_UNLOCK(fdp); 422 break; 423 424 case F_SETFL: 425 mtx_assert(&Giant, MA_OWNED); 426 FILE_LOCK(fp); 427 fhold_locked(fp); 428 fp->f_flag &= ~FCNTLFLAGS; 429 fp->f_flag |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS; 430 FILE_UNLOCK(fp); 431 FILEDESC_UNLOCK(fdp); 432 tmp = fp->f_flag & FNONBLOCK; 433 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 434 if (error) { 435 fdrop(fp, td); 436 break; 437 } 438 tmp = fp->f_flag & FASYNC; 439 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); 440 if (error == 0) { 441 fdrop(fp, td); 442 break; 443 } 444 FILE_LOCK(fp); 445 fp->f_flag &= ~FNONBLOCK; 446 FILE_UNLOCK(fp); 447 tmp = 0; 448 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 449 fdrop(fp, td); 450 break; 451 452 case F_GETOWN: 453 mtx_assert(&Giant, MA_OWNED); 454 fhold(fp); 455 FILEDESC_UNLOCK(fdp); 456 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td); 457 if (error == 0) 458 td->td_retval[0] = tmp; 459 fdrop(fp, td); 460 break; 461 462 case F_SETOWN: 463 mtx_assert(&Giant, MA_OWNED); 464 fhold(fp); 465 FILEDESC_UNLOCK(fdp); 466 tmp = arg; 467 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td); 468 fdrop(fp, td); 469 break; 470 471 case F_SETLKW: 472 mtx_assert(&Giant, MA_OWNED); 473 flg |= F_WAIT; 474 /* FALLTHROUGH F_SETLK */ 475 476 case F_SETLK: 477 mtx_assert(&Giant, MA_OWNED); 478 if (fp->f_type != DTYPE_VNODE) { 479 FILEDESC_UNLOCK(fdp); 480 error = EBADF; 481 break; 482 } 483 484 flp = (struct flock *)arg; 485 if (flp->l_whence == SEEK_CUR) { 486 if (fp->f_offset < 0 || 487 (flp->l_start > 0 && 488 fp->f_offset > OFF_MAX - flp->l_start)) { 489 FILEDESC_UNLOCK(fdp); 490 error = EOVERFLOW; 491 break; 492 } 493 flp->l_start += fp->f_offset; 494 } 495 496 /* 497 * VOP_ADVLOCK() may block. 498 */ 499 fhold(fp); 500 FILEDESC_UNLOCK(fdp); 501 vp = fp->f_vnode; 502 503 switch (flp->l_type) { 504 case F_RDLCK: 505 if ((fp->f_flag & FREAD) == 0) { 506 error = EBADF; 507 break; 508 } 509 PROC_LOCK(p->p_leader); 510 p->p_leader->p_flag |= P_ADVLOCK; 511 PROC_UNLOCK(p->p_leader); 512 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 513 flp, flg); 514 break; 515 case F_WRLCK: 516 if ((fp->f_flag & FWRITE) == 0) { 517 error = EBADF; 518 break; 519 } 520 PROC_LOCK(p->p_leader); 521 p->p_leader->p_flag |= P_ADVLOCK; 522 PROC_UNLOCK(p->p_leader); 523 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 524 flp, flg); 525 break; 526 case F_UNLCK: 527 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 528 flp, F_POSIX); 529 break; 530 default: 531 error = EINVAL; 532 break; 533 } 534 /* Check for race with close */ 535 FILEDESC_LOCK_FAST(fdp); 536 if ((unsigned) fd >= fdp->fd_nfiles || 537 fp != fdp->fd_ofiles[fd]) { 538 FILEDESC_UNLOCK_FAST(fdp); 539 flp->l_whence = SEEK_SET; 540 flp->l_start = 0; 541 flp->l_len = 0; 542 flp->l_type = F_UNLCK; 543 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 544 F_UNLCK, flp, F_POSIX); 545 } else 546 FILEDESC_UNLOCK_FAST(fdp); 547 fdrop(fp, td); 548 break; 549 550 case F_GETLK: 551 mtx_assert(&Giant, MA_OWNED); 552 if (fp->f_type != DTYPE_VNODE) { 553 FILEDESC_UNLOCK(fdp); 554 error = EBADF; 555 break; 556 } 557 flp = (struct flock *)arg; 558 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK && 559 flp->l_type != F_UNLCK) { 560 FILEDESC_UNLOCK(fdp); 561 error = EINVAL; 562 break; 563 } 564 if (flp->l_whence == SEEK_CUR) { 565 if ((flp->l_start > 0 && 566 fp->f_offset > OFF_MAX - flp->l_start) || 567 (flp->l_start < 0 && 568 fp->f_offset < OFF_MIN - flp->l_start)) { 569 FILEDESC_UNLOCK(fdp); 570 error = EOVERFLOW; 571 break; 572 } 573 flp->l_start += fp->f_offset; 574 } 575 /* 576 * VOP_ADVLOCK() may block. 577 */ 578 fhold(fp); 579 FILEDESC_UNLOCK(fdp); 580 vp = fp->f_vnode; 581 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp, 582 F_POSIX); 583 fdrop(fp, td); 584 break; 585 default: 586 FILEDESC_UNLOCK(fdp); 587 error = EINVAL; 588 break; 589 } 590 done2: 591 if (giant_locked) 592 mtx_unlock(&Giant); 593 return (error); 594 } 595 596 /* 597 * Common code for dup, dup2, and fcntl(F_DUPFD). 598 */ 599 static int 600 do_dup(struct thread *td, enum dup_type type, int old, int new, register_t *retval) 601 { 602 struct filedesc *fdp; 603 struct proc *p; 604 struct file *fp; 605 struct file *delfp; 606 int error, holdleaders, maxfd; 607 608 KASSERT((type == DUP_VARIABLE || type == DUP_FIXED), 609 ("invalid dup type %d", type)); 610 611 p = td->td_proc; 612 fdp = p->p_fd; 613 614 /* 615 * Verify we have a valid descriptor to dup from and possibly to 616 * dup to. 617 */ 618 if (old < 0 || new < 0) 619 return (EBADF); 620 PROC_LOCK(p); 621 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 622 PROC_UNLOCK(p); 623 if (new >= maxfd) 624 return (EMFILE); 625 626 FILEDESC_LOCK(fdp); 627 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) { 628 FILEDESC_UNLOCK(fdp); 629 return (EBADF); 630 } 631 if (type == DUP_FIXED && old == new) { 632 *retval = new; 633 FILEDESC_UNLOCK(fdp); 634 return (0); 635 } 636 fp = fdp->fd_ofiles[old]; 637 fhold(fp); 638 639 /* 640 * If the caller specified a file descriptor, make sure the file 641 * table is large enough to hold it, and grab it. Otherwise, just 642 * allocate a new descriptor the usual way. Since the filedesc 643 * lock may be temporarily dropped in the process, we have to look 644 * out for a race. 645 */ 646 if (type == DUP_FIXED) { 647 if (new >= fdp->fd_nfiles) 648 fdgrowtable(fdp, new + 1); 649 if (fdp->fd_ofiles[new] == NULL) 650 fdused(fdp, new); 651 } else { 652 if ((error = fdalloc(td, new, &new)) != 0) { 653 FILEDESC_UNLOCK(fdp); 654 fdrop(fp, td); 655 return (error); 656 } 657 } 658 659 /* 660 * If the old file changed out from under us then treat it as a 661 * bad file descriptor. Userland should do its own locking to 662 * avoid this case. 663 */ 664 if (fdp->fd_ofiles[old] != fp) { 665 /* we've allocated a descriptor which we won't use */ 666 if (fdp->fd_ofiles[new] == NULL) 667 fdunused(fdp, new); 668 FILEDESC_UNLOCK(fdp); 669 fdrop(fp, td); 670 return (EBADF); 671 } 672 KASSERT(old != new, 673 ("new fd is same as old")); 674 675 /* 676 * Save info on the descriptor being overwritten. We cannot close 677 * it without introducing an ownership race for the slot, since we 678 * need to drop the filedesc lock to call closef(). 679 * 680 * XXX this duplicates parts of close(). 681 */ 682 delfp = fdp->fd_ofiles[new]; 683 holdleaders = 0; 684 if (delfp != NULL) { 685 if (td->td_proc->p_fdtol != NULL) { 686 /* 687 * Ask fdfree() to sleep to ensure that all relevant 688 * process leaders can be traversed in closef(). 689 */ 690 fdp->fd_holdleaderscount++; 691 holdleaders = 1; 692 } 693 } 694 695 /* 696 * Duplicate the source descriptor 697 */ 698 fdp->fd_ofiles[new] = fp; 699 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE; 700 if (new > fdp->fd_lastfile) 701 fdp->fd_lastfile = new; 702 *retval = new; 703 704 /* 705 * If we dup'd over a valid file, we now own the reference to it 706 * and must dispose of it using closef() semantics (as if a 707 * close() were performed on it). 708 * 709 * XXX this duplicates parts of close(). 710 */ 711 if (delfp != NULL) { 712 knote_fdclose(td, new); 713 FILEDESC_UNLOCK(fdp); 714 (void) closef(delfp, td); 715 if (holdleaders) { 716 FILEDESC_LOCK_FAST(fdp); 717 fdp->fd_holdleaderscount--; 718 if (fdp->fd_holdleaderscount == 0 && 719 fdp->fd_holdleaderswakeup != 0) { 720 fdp->fd_holdleaderswakeup = 0; 721 wakeup(&fdp->fd_holdleaderscount); 722 } 723 FILEDESC_UNLOCK_FAST(fdp); 724 } 725 } else { 726 FILEDESC_UNLOCK(fdp); 727 } 728 return (0); 729 } 730 731 /* 732 * If sigio is on the list associated with a process or process group, 733 * disable signalling from the device, remove sigio from the list and 734 * free sigio. 735 */ 736 void 737 funsetown(struct sigio **sigiop) 738 { 739 struct sigio *sigio; 740 741 SIGIO_LOCK(); 742 sigio = *sigiop; 743 if (sigio == NULL) { 744 SIGIO_UNLOCK(); 745 return; 746 } 747 *(sigio->sio_myref) = NULL; 748 if ((sigio)->sio_pgid < 0) { 749 struct pgrp *pg = (sigio)->sio_pgrp; 750 PGRP_LOCK(pg); 751 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 752 sigio, sio_pgsigio); 753 PGRP_UNLOCK(pg); 754 } else { 755 struct proc *p = (sigio)->sio_proc; 756 PROC_LOCK(p); 757 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 758 sigio, sio_pgsigio); 759 PROC_UNLOCK(p); 760 } 761 SIGIO_UNLOCK(); 762 crfree(sigio->sio_ucred); 763 FREE(sigio, M_SIGIO); 764 } 765 766 /* 767 * Free a list of sigio structures. 768 * We only need to lock the SIGIO_LOCK because we have made ourselves 769 * inaccessable to callers of fsetown and therefore do not need to lock 770 * the proc or pgrp struct for the list manipulation. 771 */ 772 void 773 funsetownlst(struct sigiolst *sigiolst) 774 { 775 struct proc *p; 776 struct pgrp *pg; 777 struct sigio *sigio; 778 779 sigio = SLIST_FIRST(sigiolst); 780 if (sigio == NULL) 781 return; 782 p = NULL; 783 pg = NULL; 784 785 /* 786 * Every entry of the list should belong 787 * to a single proc or pgrp. 788 */ 789 if (sigio->sio_pgid < 0) { 790 pg = sigio->sio_pgrp; 791 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED); 792 } else /* if (sigio->sio_pgid > 0) */ { 793 p = sigio->sio_proc; 794 PROC_LOCK_ASSERT(p, MA_NOTOWNED); 795 } 796 797 SIGIO_LOCK(); 798 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) { 799 *(sigio->sio_myref) = NULL; 800 if (pg != NULL) { 801 KASSERT(sigio->sio_pgid < 0, 802 ("Proc sigio in pgrp sigio list")); 803 KASSERT(sigio->sio_pgrp == pg, 804 ("Bogus pgrp in sigio list")); 805 PGRP_LOCK(pg); 806 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio, 807 sio_pgsigio); 808 PGRP_UNLOCK(pg); 809 } else /* if (p != NULL) */ { 810 KASSERT(sigio->sio_pgid > 0, 811 ("Pgrp sigio in proc sigio list")); 812 KASSERT(sigio->sio_proc == p, 813 ("Bogus proc in sigio list")); 814 PROC_LOCK(p); 815 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, 816 sio_pgsigio); 817 PROC_UNLOCK(p); 818 } 819 SIGIO_UNLOCK(); 820 crfree(sigio->sio_ucred); 821 FREE(sigio, M_SIGIO); 822 SIGIO_LOCK(); 823 } 824 SIGIO_UNLOCK(); 825 } 826 827 /* 828 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 829 * 830 * After permission checking, add a sigio structure to the sigio list for 831 * the process or process group. 832 */ 833 int 834 fsetown(pid_t pgid, struct sigio **sigiop) 835 { 836 struct proc *proc; 837 struct pgrp *pgrp; 838 struct sigio *sigio; 839 int ret; 840 841 if (pgid == 0) { 842 funsetown(sigiop); 843 return (0); 844 } 845 846 ret = 0; 847 848 /* Allocate and fill in the new sigio out of locks. */ 849 MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK); 850 sigio->sio_pgid = pgid; 851 sigio->sio_ucred = crhold(curthread->td_ucred); 852 sigio->sio_myref = sigiop; 853 854 sx_slock(&proctree_lock); 855 if (pgid > 0) { 856 proc = pfind(pgid); 857 if (proc == NULL) { 858 ret = ESRCH; 859 goto fail; 860 } 861 862 /* 863 * Policy - Don't allow a process to FSETOWN a process 864 * in another session. 865 * 866 * Remove this test to allow maximum flexibility or 867 * restrict FSETOWN to the current process or process 868 * group for maximum safety. 869 */ 870 PROC_UNLOCK(proc); 871 if (proc->p_session != curthread->td_proc->p_session) { 872 ret = EPERM; 873 goto fail; 874 } 875 876 pgrp = NULL; 877 } else /* if (pgid < 0) */ { 878 pgrp = pgfind(-pgid); 879 if (pgrp == NULL) { 880 ret = ESRCH; 881 goto fail; 882 } 883 PGRP_UNLOCK(pgrp); 884 885 /* 886 * Policy - Don't allow a process to FSETOWN a process 887 * in another session. 888 * 889 * Remove this test to allow maximum flexibility or 890 * restrict FSETOWN to the current process or process 891 * group for maximum safety. 892 */ 893 if (pgrp->pg_session != curthread->td_proc->p_session) { 894 ret = EPERM; 895 goto fail; 896 } 897 898 proc = NULL; 899 } 900 funsetown(sigiop); 901 if (pgid > 0) { 902 PROC_LOCK(proc); 903 /* 904 * Since funsetownlst() is called without the proctree 905 * locked, we need to check for P_WEXIT. 906 * XXX: is ESRCH correct? 907 */ 908 if ((proc->p_flag & P_WEXIT) != 0) { 909 PROC_UNLOCK(proc); 910 ret = ESRCH; 911 goto fail; 912 } 913 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 914 sigio->sio_proc = proc; 915 PROC_UNLOCK(proc); 916 } else { 917 PGRP_LOCK(pgrp); 918 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 919 sigio->sio_pgrp = pgrp; 920 PGRP_UNLOCK(pgrp); 921 } 922 sx_sunlock(&proctree_lock); 923 SIGIO_LOCK(); 924 *sigiop = sigio; 925 SIGIO_UNLOCK(); 926 return (0); 927 928 fail: 929 sx_sunlock(&proctree_lock); 930 crfree(sigio->sio_ucred); 931 FREE(sigio, M_SIGIO); 932 return (ret); 933 } 934 935 /* 936 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 937 */ 938 pid_t 939 fgetown(sigiop) 940 struct sigio **sigiop; 941 { 942 pid_t pgid; 943 944 SIGIO_LOCK(); 945 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0; 946 SIGIO_UNLOCK(); 947 return (pgid); 948 } 949 950 /* 951 * Close a file descriptor. 952 */ 953 #ifndef _SYS_SYSPROTO_H_ 954 struct close_args { 955 int fd; 956 }; 957 #endif 958 /* 959 * MPSAFE 960 */ 961 /* ARGSUSED */ 962 int 963 close(td, uap) 964 struct thread *td; 965 struct close_args *uap; 966 { 967 struct filedesc *fdp; 968 struct file *fp; 969 int fd, error; 970 int holdleaders; 971 972 fd = uap->fd; 973 error = 0; 974 holdleaders = 0; 975 fdp = td->td_proc->p_fd; 976 FILEDESC_LOCK(fdp); 977 if ((unsigned)fd >= fdp->fd_nfiles || 978 (fp = fdp->fd_ofiles[fd]) == NULL) { 979 FILEDESC_UNLOCK(fdp); 980 return (EBADF); 981 } 982 fdp->fd_ofiles[fd] = NULL; 983 fdp->fd_ofileflags[fd] = 0; 984 fdunused(fdp, fd); 985 if (td->td_proc->p_fdtol != NULL) { 986 /* 987 * Ask fdfree() to sleep to ensure that all relevant 988 * process leaders can be traversed in closef(). 989 */ 990 fdp->fd_holdleaderscount++; 991 holdleaders = 1; 992 } 993 994 /* 995 * we now hold the fp reference that used to be owned by the descriptor 996 * array. 997 * We have to unlock the FILEDESC *AFTER* knote_fdclose to prevent a 998 * race of the fd getting opened, a knote added, and deleteing a knote 999 * for the new fd. 1000 */ 1001 knote_fdclose(td, fd); 1002 FILEDESC_UNLOCK(fdp); 1003 1004 error = closef(fp, td); 1005 if (holdleaders) { 1006 FILEDESC_LOCK_FAST(fdp); 1007 fdp->fd_holdleaderscount--; 1008 if (fdp->fd_holdleaderscount == 0 && 1009 fdp->fd_holdleaderswakeup != 0) { 1010 fdp->fd_holdleaderswakeup = 0; 1011 wakeup(&fdp->fd_holdleaderscount); 1012 } 1013 FILEDESC_UNLOCK_FAST(fdp); 1014 } 1015 return (error); 1016 } 1017 1018 #if defined(COMPAT_43) 1019 /* 1020 * Return status information about a file descriptor. 1021 */ 1022 #ifndef _SYS_SYSPROTO_H_ 1023 struct ofstat_args { 1024 int fd; 1025 struct ostat *sb; 1026 }; 1027 #endif 1028 /* 1029 * MPSAFE 1030 */ 1031 /* ARGSUSED */ 1032 int 1033 ofstat(struct thread *td, struct ofstat_args *uap) 1034 { 1035 struct file *fp; 1036 struct stat ub; 1037 struct ostat oub; 1038 int error; 1039 1040 if ((error = fget(td, uap->fd, &fp)) != 0) 1041 goto done2; 1042 error = fo_stat(fp, &ub, td->td_ucred, td); 1043 if (error == 0) { 1044 cvtstat(&ub, &oub); 1045 error = copyout(&oub, uap->sb, sizeof(oub)); 1046 } 1047 fdrop(fp, td); 1048 done2: 1049 return (error); 1050 } 1051 #endif /* COMPAT_43 */ 1052 1053 /* 1054 * Return status information about a file descriptor. 1055 */ 1056 #ifndef _SYS_SYSPROTO_H_ 1057 struct fstat_args { 1058 int fd; 1059 struct stat *sb; 1060 }; 1061 #endif 1062 /* 1063 * MPSAFE 1064 */ 1065 /* ARGSUSED */ 1066 int 1067 fstat(struct thread *td, struct fstat_args *uap) 1068 { 1069 struct file *fp; 1070 struct stat ub; 1071 int error; 1072 1073 if ((error = fget(td, uap->fd, &fp)) != 0) 1074 goto done2; 1075 error = fo_stat(fp, &ub, td->td_ucred, td); 1076 if (error == 0) 1077 error = copyout(&ub, uap->sb, sizeof(ub)); 1078 fdrop(fp, td); 1079 done2: 1080 return (error); 1081 } 1082 1083 /* 1084 * Return status information about a file descriptor. 1085 */ 1086 #ifndef _SYS_SYSPROTO_H_ 1087 struct nfstat_args { 1088 int fd; 1089 struct nstat *sb; 1090 }; 1091 #endif 1092 /* 1093 * MPSAFE 1094 */ 1095 /* ARGSUSED */ 1096 int 1097 nfstat(struct thread *td, struct nfstat_args *uap) 1098 { 1099 struct file *fp; 1100 struct stat ub; 1101 struct nstat nub; 1102 int error; 1103 1104 if ((error = fget(td, uap->fd, &fp)) != 0) 1105 goto done2; 1106 error = fo_stat(fp, &ub, td->td_ucred, td); 1107 if (error == 0) { 1108 cvtnstat(&ub, &nub); 1109 error = copyout(&nub, uap->sb, sizeof(nub)); 1110 } 1111 fdrop(fp, td); 1112 done2: 1113 return (error); 1114 } 1115 1116 /* 1117 * Return pathconf information about a file descriptor. 1118 */ 1119 #ifndef _SYS_SYSPROTO_H_ 1120 struct fpathconf_args { 1121 int fd; 1122 int name; 1123 }; 1124 #endif 1125 /* 1126 * MPSAFE 1127 */ 1128 /* ARGSUSED */ 1129 int 1130 fpathconf(struct thread *td, struct fpathconf_args *uap) 1131 { 1132 struct file *fp; 1133 struct vnode *vp; 1134 int error; 1135 1136 if ((error = fget(td, uap->fd, &fp)) != 0) 1137 return (error); 1138 1139 /* If asynchronous I/O is available, it works for all descriptors. */ 1140 if (uap->name == _PC_ASYNC_IO) { 1141 td->td_retval[0] = async_io_version; 1142 goto out; 1143 } 1144 vp = fp->f_vnode; 1145 if (vp != NULL) { 1146 mtx_lock(&Giant); 1147 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 1148 error = VOP_PATHCONF(vp, uap->name, td->td_retval); 1149 VOP_UNLOCK(vp, 0, td); 1150 mtx_unlock(&Giant); 1151 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) { 1152 if (uap->name != _PC_PIPE_BUF) { 1153 error = EINVAL; 1154 } else { 1155 td->td_retval[0] = PIPE_BUF; 1156 error = 0; 1157 } 1158 } else { 1159 error = EOPNOTSUPP; 1160 } 1161 out: 1162 fdrop(fp, td); 1163 return (error); 1164 } 1165 1166 /* 1167 * Grow the file table to accomodate (at least) nfd descriptors. This may 1168 * block and drop the filedesc lock, but it will reacquire it before 1169 * returing. 1170 */ 1171 static void 1172 fdgrowtable(struct filedesc *fdp, int nfd) 1173 { 1174 struct file **ntable; 1175 char *nfileflags; 1176 int nnfiles, onfiles; 1177 NDSLOTTYPE *nmap; 1178 1179 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1180 1181 KASSERT(fdp->fd_nfiles > 0, 1182 ("zero-length file table")); 1183 1184 /* compute the size of the new table */ 1185 onfiles = fdp->fd_nfiles; 1186 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */ 1187 if (nnfiles <= onfiles) 1188 /* the table is already large enough */ 1189 return; 1190 1191 /* allocate a new table and (if required) new bitmaps */ 1192 FILEDESC_UNLOCK(fdp); 1193 MALLOC(ntable, struct file **, nnfiles * OFILESIZE, 1194 M_FILEDESC, M_ZERO | M_WAITOK); 1195 nfileflags = (char *)&ntable[nnfiles]; 1196 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) 1197 MALLOC(nmap, NDSLOTTYPE *, NDSLOTS(nnfiles) * NDSLOTSIZE, 1198 M_FILEDESC, M_ZERO | M_WAITOK); 1199 else 1200 nmap = NULL; 1201 FILEDESC_LOCK(fdp); 1202 1203 /* 1204 * We now have new tables ready to go. Since we dropped the 1205 * filedesc lock to call malloc(), watch out for a race. 1206 */ 1207 onfiles = fdp->fd_nfiles; 1208 if (onfiles >= nnfiles) { 1209 /* we lost the race, but that's OK */ 1210 free(ntable, M_FILEDESC); 1211 if (nmap != NULL) 1212 free(nmap, M_FILEDESC); 1213 return; 1214 } 1215 bcopy(fdp->fd_ofiles, ntable, onfiles * sizeof(*ntable)); 1216 bcopy(fdp->fd_ofileflags, nfileflags, onfiles); 1217 if (onfiles > NDFILE) 1218 free(fdp->fd_ofiles, M_FILEDESC); 1219 fdp->fd_ofiles = ntable; 1220 fdp->fd_ofileflags = nfileflags; 1221 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) { 1222 bcopy(fdp->fd_map, nmap, NDSLOTS(onfiles) * sizeof(*nmap)); 1223 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE)) 1224 free(fdp->fd_map, M_FILEDESC); 1225 fdp->fd_map = nmap; 1226 } 1227 fdp->fd_nfiles = nnfiles; 1228 } 1229 1230 /* 1231 * Allocate a file descriptor for the process. 1232 */ 1233 int 1234 fdalloc(struct thread *td, int minfd, int *result) 1235 { 1236 struct proc *p = td->td_proc; 1237 struct filedesc *fdp = p->p_fd; 1238 int fd = -1, maxfd; 1239 1240 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1241 1242 PROC_LOCK(p); 1243 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1244 PROC_UNLOCK(p); 1245 1246 /* 1247 * Search the bitmap for a free descriptor. If none is found, try 1248 * to grow the file table. Keep at it until we either get a file 1249 * descriptor or run into process or system limits; fdgrowtable() 1250 * may drop the filedesc lock, so we're in a race. 1251 */ 1252 for (;;) { 1253 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); 1254 if (fd >= maxfd) 1255 return (EMFILE); 1256 if (fd < fdp->fd_nfiles) 1257 break; 1258 fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd)); 1259 } 1260 1261 /* 1262 * Perform some sanity checks, then mark the file descriptor as 1263 * used and return it to the caller. 1264 */ 1265 KASSERT(!fdisused(fdp, fd), 1266 ("fd_first_free() returned non-free descriptor")); 1267 KASSERT(fdp->fd_ofiles[fd] == NULL, 1268 ("free descriptor isn't")); 1269 fdp->fd_ofileflags[fd] = 0; /* XXX needed? */ 1270 fdused(fdp, fd); 1271 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 1272 *result = fd; 1273 return (0); 1274 } 1275 1276 /* 1277 * Check to see whether n user file descriptors 1278 * are available to the process p. 1279 */ 1280 int 1281 fdavail(struct thread *td, int n) 1282 { 1283 struct proc *p = td->td_proc; 1284 struct filedesc *fdp = td->td_proc->p_fd; 1285 struct file **fpp; 1286 int i, lim, last; 1287 1288 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1289 1290 PROC_LOCK(p); 1291 lim = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1292 PROC_UNLOCK(p); 1293 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) 1294 return (1); 1295 last = min(fdp->fd_nfiles, lim); 1296 fpp = &fdp->fd_ofiles[fdp->fd_freefile]; 1297 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) { 1298 if (*fpp == NULL && --n <= 0) 1299 return (1); 1300 } 1301 return (0); 1302 } 1303 1304 /* 1305 * Create a new open file structure and allocate 1306 * a file decriptor for the process that refers to it. 1307 * We add one reference to the file for the descriptor table 1308 * and one reference for resultfp. This is to prevent us being 1309 * prempted and the entry in the descriptor table closed after 1310 * we release the FILEDESC lock. 1311 */ 1312 int 1313 falloc(struct thread *td, struct file **resultfp, int *resultfd) 1314 { 1315 struct proc *p = td->td_proc; 1316 struct file *fp, *fq; 1317 int error, i; 1318 int maxuserfiles = maxfiles - (maxfiles / 20); 1319 static struct timeval lastfail; 1320 static int curfail; 1321 1322 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO); 1323 sx_xlock(&filelist_lock); 1324 if ((nfiles >= maxuserfiles && (td->td_ucred->cr_ruid != 0 || 1325 jailed(td->td_ucred))) || nfiles >= maxfiles) { 1326 if (ppsratecheck(&lastfail, &curfail, 1)) { 1327 printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n", 1328 td->td_ucred->cr_ruid); 1329 } 1330 sx_xunlock(&filelist_lock); 1331 uma_zfree(file_zone, fp); 1332 return (ENFILE); 1333 } 1334 nfiles++; 1335 1336 /* 1337 * If the process has file descriptor zero open, add the new file 1338 * descriptor to the list of open files at that point, otherwise 1339 * put it at the front of the list of open files. 1340 */ 1341 fp->f_mtxp = mtx_pool_alloc(mtxpool_sleep); 1342 fp->f_count = 1; 1343 if (resultfp) 1344 fp->f_count++; 1345 fp->f_cred = crhold(td->td_ucred); 1346 fp->f_ops = &badfileops; 1347 fp->f_data = NULL; 1348 fp->f_vnode = NULL; 1349 FILEDESC_LOCK(p->p_fd); 1350 if ((fq = p->p_fd->fd_ofiles[0])) { 1351 LIST_INSERT_AFTER(fq, fp, f_list); 1352 } else { 1353 LIST_INSERT_HEAD(&filehead, fp, f_list); 1354 } 1355 sx_xunlock(&filelist_lock); 1356 if ((error = fdalloc(td, 0, &i))) { 1357 FILEDESC_UNLOCK(p->p_fd); 1358 fdrop(fp, td); 1359 if (resultfp) 1360 fdrop(fp, td); 1361 return (error); 1362 } 1363 p->p_fd->fd_ofiles[i] = fp; 1364 FILEDESC_UNLOCK(p->p_fd); 1365 if (resultfp) 1366 *resultfp = fp; 1367 if (resultfd) 1368 *resultfd = i; 1369 return (0); 1370 } 1371 1372 /* 1373 * Build a new filedesc structure from another. 1374 * Copy the current, root, and jail root vnode references. 1375 */ 1376 struct filedesc * 1377 fdinit(struct filedesc *fdp) 1378 { 1379 struct filedesc0 *newfdp; 1380 1381 newfdp = malloc(sizeof *newfdp, M_FILEDESC, M_WAITOK | M_ZERO); 1382 mtx_init(&newfdp->fd_fd.fd_mtx, FILEDESC_LOCK_DESC, NULL, MTX_DEF); 1383 if (fdp != NULL) { 1384 FILEDESC_LOCK(fdp); 1385 newfdp->fd_fd.fd_cdir = fdp->fd_cdir; 1386 if (newfdp->fd_fd.fd_cdir) 1387 VREF(newfdp->fd_fd.fd_cdir); 1388 newfdp->fd_fd.fd_rdir = fdp->fd_rdir; 1389 if (newfdp->fd_fd.fd_rdir) 1390 VREF(newfdp->fd_fd.fd_rdir); 1391 newfdp->fd_fd.fd_jdir = fdp->fd_jdir; 1392 if (newfdp->fd_fd.fd_jdir) 1393 VREF(newfdp->fd_fd.fd_jdir); 1394 FILEDESC_UNLOCK(fdp); 1395 } 1396 1397 /* Create the file descriptor table. */ 1398 newfdp->fd_fd.fd_refcnt = 1; 1399 newfdp->fd_fd.fd_holdcnt = 1; 1400 newfdp->fd_fd.fd_cmask = CMASK; 1401 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; 1402 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; 1403 newfdp->fd_fd.fd_nfiles = NDFILE; 1404 newfdp->fd_fd.fd_map = newfdp->fd_dmap; 1405 return (&newfdp->fd_fd); 1406 } 1407 1408 static struct filedesc * 1409 fdhold(struct proc *p) 1410 { 1411 struct filedesc *fdp; 1412 1413 mtx_lock(&fdesc_mtx); 1414 fdp = p->p_fd; 1415 if (fdp != NULL) 1416 fdp->fd_holdcnt++; 1417 mtx_unlock(&fdesc_mtx); 1418 return (fdp); 1419 } 1420 1421 static void 1422 fddrop(struct filedesc *fdp) 1423 { 1424 int i; 1425 1426 mtx_lock(&fdesc_mtx); 1427 i = --fdp->fd_holdcnt; 1428 mtx_unlock(&fdesc_mtx); 1429 if (i > 0) 1430 return; 1431 1432 mtx_destroy(&fdp->fd_mtx); 1433 FREE(fdp, M_FILEDESC); 1434 } 1435 1436 /* 1437 * Share a filedesc structure. 1438 */ 1439 struct filedesc * 1440 fdshare(struct filedesc *fdp) 1441 { 1442 FILEDESC_LOCK_FAST(fdp); 1443 fdp->fd_refcnt++; 1444 FILEDESC_UNLOCK_FAST(fdp); 1445 return (fdp); 1446 } 1447 1448 /* 1449 * Unshare a filedesc structure, if necessary by making a copy 1450 */ 1451 void 1452 fdunshare(struct proc *p, struct thread *td) 1453 { 1454 1455 FILEDESC_LOCK_FAST(p->p_fd); 1456 if (p->p_fd->fd_refcnt > 1) { 1457 struct filedesc *tmp; 1458 1459 FILEDESC_UNLOCK_FAST(p->p_fd); 1460 tmp = fdcopy(p->p_fd); 1461 fdfree(td); 1462 p->p_fd = tmp; 1463 } else 1464 FILEDESC_UNLOCK_FAST(p->p_fd); 1465 } 1466 1467 /* 1468 * Copy a filedesc structure. 1469 * A NULL pointer in returns a NULL reference, this is to ease callers, 1470 * not catch errors. 1471 */ 1472 struct filedesc * 1473 fdcopy(struct filedesc *fdp) 1474 { 1475 struct filedesc *newfdp; 1476 int i; 1477 1478 /* Certain daemons might not have file descriptors. */ 1479 if (fdp == NULL) 1480 return (NULL); 1481 1482 newfdp = fdinit(fdp); 1483 FILEDESC_LOCK_FAST(fdp); 1484 while (fdp->fd_lastfile >= newfdp->fd_nfiles) { 1485 FILEDESC_UNLOCK_FAST(fdp); 1486 FILEDESC_LOCK(newfdp); 1487 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1488 FILEDESC_UNLOCK(newfdp); 1489 FILEDESC_LOCK_FAST(fdp); 1490 } 1491 /* copy everything except kqueue descriptors */ 1492 newfdp->fd_freefile = -1; 1493 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1494 if (fdisused(fdp, i) && 1495 fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE) { 1496 newfdp->fd_ofiles[i] = fdp->fd_ofiles[i]; 1497 newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i]; 1498 fhold(newfdp->fd_ofiles[i]); 1499 newfdp->fd_lastfile = i; 1500 } else { 1501 if (newfdp->fd_freefile == -1) 1502 newfdp->fd_freefile = i; 1503 } 1504 } 1505 FILEDESC_UNLOCK_FAST(fdp); 1506 FILEDESC_LOCK(newfdp); 1507 for (i = 0; i <= newfdp->fd_lastfile; ++i) 1508 if (newfdp->fd_ofiles[i] != NULL) 1509 fdused(newfdp, i); 1510 FILEDESC_UNLOCK(newfdp); 1511 FILEDESC_LOCK_FAST(fdp); 1512 if (newfdp->fd_freefile == -1) 1513 newfdp->fd_freefile = i; 1514 newfdp->fd_cmask = fdp->fd_cmask; 1515 FILEDESC_UNLOCK_FAST(fdp); 1516 return (newfdp); 1517 } 1518 1519 /* 1520 * Release a filedesc structure. 1521 */ 1522 void 1523 fdfree(struct thread *td) 1524 { 1525 struct filedesc *fdp; 1526 struct file **fpp; 1527 int i; 1528 struct filedesc_to_leader *fdtol; 1529 struct file *fp; 1530 struct vnode *vp; 1531 struct flock lf; 1532 1533 GIANT_REQUIRED; /* VFS */ 1534 1535 /* Certain daemons might not have file descriptors. */ 1536 fdp = td->td_proc->p_fd; 1537 if (fdp == NULL) 1538 return; 1539 1540 /* Check for special need to clear POSIX style locks */ 1541 fdtol = td->td_proc->p_fdtol; 1542 if (fdtol != NULL) { 1543 FILEDESC_LOCK(fdp); 1544 KASSERT(fdtol->fdl_refcount > 0, 1545 ("filedesc_to_refcount botch: fdl_refcount=%d", 1546 fdtol->fdl_refcount)); 1547 if (fdtol->fdl_refcount == 1 && 1548 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1549 i = 0; 1550 fpp = fdp->fd_ofiles; 1551 for (i = 0, fpp = fdp->fd_ofiles; 1552 i <= fdp->fd_lastfile; 1553 i++, fpp++) { 1554 if (*fpp == NULL || 1555 (*fpp)->f_type != DTYPE_VNODE) 1556 continue; 1557 fp = *fpp; 1558 fhold(fp); 1559 FILEDESC_UNLOCK(fdp); 1560 lf.l_whence = SEEK_SET; 1561 lf.l_start = 0; 1562 lf.l_len = 0; 1563 lf.l_type = F_UNLCK; 1564 vp = fp->f_vnode; 1565 (void) VOP_ADVLOCK(vp, 1566 (caddr_t)td->td_proc-> 1567 p_leader, 1568 F_UNLCK, 1569 &lf, 1570 F_POSIX); 1571 FILEDESC_LOCK(fdp); 1572 fdrop(fp, td); 1573 fpp = fdp->fd_ofiles + i; 1574 } 1575 } 1576 retry: 1577 if (fdtol->fdl_refcount == 1) { 1578 if (fdp->fd_holdleaderscount > 0 && 1579 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1580 /* 1581 * close() or do_dup() has cleared a reference 1582 * in a shared file descriptor table. 1583 */ 1584 fdp->fd_holdleaderswakeup = 1; 1585 msleep(&fdp->fd_holdleaderscount, &fdp->fd_mtx, 1586 PLOCK, "fdlhold", 0); 1587 goto retry; 1588 } 1589 if (fdtol->fdl_holdcount > 0) { 1590 /* 1591 * Ensure that fdtol->fdl_leader 1592 * remains valid in closef(). 1593 */ 1594 fdtol->fdl_wakeup = 1; 1595 msleep(fdtol, &fdp->fd_mtx, 1596 PLOCK, "fdlhold", 0); 1597 goto retry; 1598 } 1599 } 1600 fdtol->fdl_refcount--; 1601 if (fdtol->fdl_refcount == 0 && 1602 fdtol->fdl_holdcount == 0) { 1603 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1604 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1605 } else 1606 fdtol = NULL; 1607 td->td_proc->p_fdtol = NULL; 1608 FILEDESC_UNLOCK(fdp); 1609 if (fdtol != NULL) 1610 FREE(fdtol, M_FILEDESC_TO_LEADER); 1611 } 1612 FILEDESC_LOCK_FAST(fdp); 1613 i = --fdp->fd_refcnt; 1614 FILEDESC_UNLOCK_FAST(fdp); 1615 if (i > 0) 1616 return; 1617 /* 1618 * We are the last reference to the structure, so we can 1619 * safely assume it will not change out from under us. 1620 */ 1621 fpp = fdp->fd_ofiles; 1622 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) { 1623 if (*fpp) 1624 (void) closef(*fpp, td); 1625 } 1626 FILEDESC_LOCK(fdp); 1627 1628 /* XXX This should happen earlier. */ 1629 mtx_lock(&fdesc_mtx); 1630 td->td_proc->p_fd = NULL; 1631 mtx_unlock(&fdesc_mtx); 1632 1633 if (fdp->fd_nfiles > NDFILE) 1634 FREE(fdp->fd_ofiles, M_FILEDESC); 1635 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE)) 1636 FREE(fdp->fd_map, M_FILEDESC); 1637 1638 fdp->fd_nfiles = 0; 1639 1640 if (fdp->fd_cdir) 1641 vrele(fdp->fd_cdir); 1642 fdp->fd_cdir = NULL; 1643 if (fdp->fd_rdir) 1644 vrele(fdp->fd_rdir); 1645 fdp->fd_rdir = NULL; 1646 if (fdp->fd_jdir) 1647 vrele(fdp->fd_jdir); 1648 fdp->fd_jdir = NULL; 1649 1650 FILEDESC_UNLOCK(fdp); 1651 1652 fddrop(fdp); 1653 } 1654 1655 /* 1656 * For setugid programs, we don't want to people to use that setugidness 1657 * to generate error messages which write to a file which otherwise would 1658 * otherwise be off-limits to the process. We check for filesystems where 1659 * the vnode can change out from under us after execve (like [lin]procfs). 1660 * 1661 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 1662 * sufficient. We also don't for check setugidness since we know we are. 1663 */ 1664 static int 1665 is_unsafe(struct file *fp) 1666 { 1667 if (fp->f_type == DTYPE_VNODE) { 1668 struct vnode *vp = fp->f_vnode; 1669 1670 if ((vp->v_vflag & VV_PROCDEP) != 0) 1671 return (1); 1672 } 1673 return (0); 1674 } 1675 1676 /* 1677 * Make this setguid thing safe, if at all possible. 1678 */ 1679 void 1680 setugidsafety(struct thread *td) 1681 { 1682 struct filedesc *fdp; 1683 int i; 1684 1685 /* Certain daemons might not have file descriptors. */ 1686 fdp = td->td_proc->p_fd; 1687 if (fdp == NULL) 1688 return; 1689 1690 /* 1691 * Note: fdp->fd_ofiles may be reallocated out from under us while 1692 * we are blocked in a close. Be careful! 1693 */ 1694 FILEDESC_LOCK(fdp); 1695 for (i = 0; i <= fdp->fd_lastfile; i++) { 1696 if (i > 2) 1697 break; 1698 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) { 1699 struct file *fp; 1700 1701 knote_fdclose(td, i); 1702 /* 1703 * NULL-out descriptor prior to close to avoid 1704 * a race while close blocks. 1705 */ 1706 fp = fdp->fd_ofiles[i]; 1707 fdp->fd_ofiles[i] = NULL; 1708 fdp->fd_ofileflags[i] = 0; 1709 fdunused(fdp, i); 1710 FILEDESC_UNLOCK(fdp); 1711 (void) closef(fp, td); 1712 FILEDESC_LOCK(fdp); 1713 } 1714 } 1715 FILEDESC_UNLOCK(fdp); 1716 } 1717 1718 void 1719 fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td) 1720 { 1721 1722 FILEDESC_LOCK(fdp); 1723 if (fdp->fd_ofiles[idx] == fp) { 1724 fdp->fd_ofiles[idx] = NULL; 1725 fdunused(fdp, idx); 1726 FILEDESC_UNLOCK(fdp); 1727 fdrop(fp, td); 1728 } else { 1729 FILEDESC_UNLOCK(fdp); 1730 } 1731 } 1732 1733 /* 1734 * Close any files on exec? 1735 */ 1736 void 1737 fdcloseexec(struct thread *td) 1738 { 1739 struct filedesc *fdp; 1740 int i; 1741 1742 /* Certain daemons might not have file descriptors. */ 1743 fdp = td->td_proc->p_fd; 1744 if (fdp == NULL) 1745 return; 1746 1747 FILEDESC_LOCK(fdp); 1748 1749 /* 1750 * We cannot cache fd_ofiles or fd_ofileflags since operations 1751 * may block and rip them out from under us. 1752 */ 1753 for (i = 0; i <= fdp->fd_lastfile; i++) { 1754 if (fdp->fd_ofiles[i] != NULL && 1755 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) { 1756 struct file *fp; 1757 1758 knote_fdclose(td, i); 1759 /* 1760 * NULL-out descriptor prior to close to avoid 1761 * a race while close blocks. 1762 */ 1763 fp = fdp->fd_ofiles[i]; 1764 fdp->fd_ofiles[i] = NULL; 1765 fdp->fd_ofileflags[i] = 0; 1766 fdunused(fdp, i); 1767 FILEDESC_UNLOCK(fdp); 1768 (void) closef(fp, td); 1769 FILEDESC_LOCK(fdp); 1770 } 1771 } 1772 FILEDESC_UNLOCK(fdp); 1773 } 1774 1775 /* 1776 * It is unsafe for set[ug]id processes to be started with file 1777 * descriptors 0..2 closed, as these descriptors are given implicit 1778 * significance in the Standard C library. fdcheckstd() will create a 1779 * descriptor referencing /dev/null for each of stdin, stdout, and 1780 * stderr that is not already open. 1781 */ 1782 int 1783 fdcheckstd(struct thread *td) 1784 { 1785 struct nameidata nd; 1786 struct filedesc *fdp; 1787 struct file *fp; 1788 register_t retval; 1789 int fd, i, error, flags, devnull; 1790 1791 GIANT_REQUIRED; /* VFS */ 1792 1793 fdp = td->td_proc->p_fd; 1794 if (fdp == NULL) 1795 return (0); 1796 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 1797 devnull = -1; 1798 error = 0; 1799 for (i = 0; i < 3; i++) { 1800 if (fdp->fd_ofiles[i] != NULL) 1801 continue; 1802 if (devnull < 0) { 1803 error = falloc(td, &fp, &fd); 1804 if (error != 0) 1805 break; 1806 /* Note extra ref on `fp' held for us by falloc(). */ 1807 KASSERT(fd == i, ("oof, we didn't get our fd")); 1808 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/null", 1809 td); 1810 flags = FREAD | FWRITE; 1811 error = vn_open(&nd, &flags, 0, -1); 1812 if (error != 0) { 1813 /* 1814 * Someone may have closed the entry in the 1815 * file descriptor table, so check it hasn't 1816 * changed before dropping the reference count. 1817 */ 1818 FILEDESC_LOCK(fdp); 1819 KASSERT(fdp->fd_ofiles[fd] == fp, 1820 ("table not shared, how did it change?")); 1821 fdp->fd_ofiles[fd] = NULL; 1822 fdunused(fdp, fd); 1823 FILEDESC_UNLOCK(fdp); 1824 fdrop(fp, td); 1825 fdrop(fp, td); 1826 break; 1827 } 1828 NDFREE(&nd, NDF_ONLY_PNBUF); 1829 fp->f_flag = flags; 1830 fp->f_vnode = nd.ni_vp; 1831 if (fp->f_data == NULL) 1832 fp->f_data = nd.ni_vp; 1833 if (fp->f_ops == &badfileops) 1834 fp->f_ops = &vnops; 1835 fp->f_type = DTYPE_VNODE; 1836 VOP_UNLOCK(nd.ni_vp, 0, td); 1837 devnull = fd; 1838 fdrop(fp, td); 1839 } else { 1840 error = do_dup(td, DUP_FIXED, devnull, i, &retval); 1841 if (error != 0) 1842 break; 1843 } 1844 } 1845 return (error); 1846 } 1847 1848 /* 1849 * Internal form of close. 1850 * Decrement reference count on file structure. 1851 * Note: td may be NULL when closing a file that was being passed in a 1852 * message. 1853 * 1854 * XXXRW: Giant is not required for the caller, but often will be held; this 1855 * makes it moderately likely the Giant will be recursed in the VFS case. 1856 */ 1857 int 1858 closef(struct file *fp, struct thread *td) 1859 { 1860 struct vnode *vp; 1861 struct flock lf; 1862 struct filedesc_to_leader *fdtol; 1863 struct filedesc *fdp; 1864 1865 /* 1866 * POSIX record locking dictates that any close releases ALL 1867 * locks owned by this process. This is handled by setting 1868 * a flag in the unlock to free ONLY locks obeying POSIX 1869 * semantics, and not to free BSD-style file locks. 1870 * If the descriptor was in a message, POSIX-style locks 1871 * aren't passed with the descriptor. 1872 */ 1873 if (fp->f_type == DTYPE_VNODE) { 1874 mtx_lock(&Giant); 1875 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1876 lf.l_whence = SEEK_SET; 1877 lf.l_start = 0; 1878 lf.l_len = 0; 1879 lf.l_type = F_UNLCK; 1880 vp = fp->f_vnode; 1881 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader, 1882 F_UNLCK, &lf, F_POSIX); 1883 } 1884 fdtol = td->td_proc->p_fdtol; 1885 if (fdtol != NULL) { 1886 /* 1887 * Handle special case where file descriptor table 1888 * is shared between multiple process leaders. 1889 */ 1890 fdp = td->td_proc->p_fd; 1891 FILEDESC_LOCK(fdp); 1892 for (fdtol = fdtol->fdl_next; 1893 fdtol != td->td_proc->p_fdtol; 1894 fdtol = fdtol->fdl_next) { 1895 if ((fdtol->fdl_leader->p_flag & 1896 P_ADVLOCK) == 0) 1897 continue; 1898 fdtol->fdl_holdcount++; 1899 FILEDESC_UNLOCK(fdp); 1900 lf.l_whence = SEEK_SET; 1901 lf.l_start = 0; 1902 lf.l_len = 0; 1903 lf.l_type = F_UNLCK; 1904 vp = fp->f_vnode; 1905 (void) VOP_ADVLOCK(vp, 1906 (caddr_t)fdtol->fdl_leader, 1907 F_UNLCK, &lf, F_POSIX); 1908 FILEDESC_LOCK(fdp); 1909 fdtol->fdl_holdcount--; 1910 if (fdtol->fdl_holdcount == 0 && 1911 fdtol->fdl_wakeup != 0) { 1912 fdtol->fdl_wakeup = 0; 1913 wakeup(fdtol); 1914 } 1915 } 1916 FILEDESC_UNLOCK(fdp); 1917 } 1918 mtx_unlock(&Giant); 1919 } 1920 return (fdrop(fp, td)); 1921 } 1922 1923 /* 1924 * Extract the file pointer associated with the specified descriptor for 1925 * the current user process. 1926 * 1927 * If the descriptor doesn't exist, EBADF is returned. 1928 * 1929 * If the descriptor exists but doesn't match 'flags' then 1930 * return EBADF for read attempts and EINVAL for write attempts. 1931 * 1932 * If 'hold' is set (non-zero) the file's refcount will be bumped on return. 1933 * It should be droped with fdrop(). 1934 * If it is not set, then the refcount will not be bumped however the 1935 * thread's filedesc struct will be returned locked (for fgetsock). 1936 * 1937 * If an error occured the non-zero error is returned and *fpp is set to NULL. 1938 * Otherwise *fpp is set and zero is returned. 1939 */ 1940 static __inline int 1941 _fget(struct thread *td, int fd, struct file **fpp, int flags, int hold) 1942 { 1943 struct filedesc *fdp; 1944 struct file *fp; 1945 1946 *fpp = NULL; 1947 if (td == NULL || (fdp = td->td_proc->p_fd) == NULL) 1948 return (EBADF); 1949 FILEDESC_LOCK(fdp); 1950 if ((fp = fget_locked(fdp, fd)) == NULL || fp->f_ops == &badfileops) { 1951 FILEDESC_UNLOCK(fdp); 1952 return (EBADF); 1953 } 1954 1955 /* 1956 * Note: FREAD failures returns EBADF to maintain backwards 1957 * compatibility with what routines returned before. 1958 * 1959 * Only one flag, or 0, may be specified. 1960 */ 1961 if (flags == FREAD && (fp->f_flag & FREAD) == 0) { 1962 FILEDESC_UNLOCK(fdp); 1963 return (EBADF); 1964 } 1965 if (flags == FWRITE && (fp->f_flag & FWRITE) == 0) { 1966 FILEDESC_UNLOCK(fdp); 1967 return (EINVAL); 1968 } 1969 if (hold) { 1970 fhold(fp); 1971 FILEDESC_UNLOCK(fdp); 1972 } 1973 *fpp = fp; 1974 return (0); 1975 } 1976 1977 int 1978 fget(struct thread *td, int fd, struct file **fpp) 1979 { 1980 1981 return(_fget(td, fd, fpp, 0, 1)); 1982 } 1983 1984 int 1985 fget_read(struct thread *td, int fd, struct file **fpp) 1986 { 1987 1988 return(_fget(td, fd, fpp, FREAD, 1)); 1989 } 1990 1991 int 1992 fget_write(struct thread *td, int fd, struct file **fpp) 1993 { 1994 1995 return(_fget(td, fd, fpp, FWRITE, 1)); 1996 } 1997 1998 /* 1999 * Like fget() but loads the underlying vnode, or returns an error if 2000 * the descriptor does not represent a vnode. Note that pipes use vnodes 2001 * but never have VM objects (so VOP_GETVOBJECT() calls will return an 2002 * error). The returned vnode will be vref()d. 2003 * 2004 * XXX: what about the unused flags ? 2005 */ 2006 static __inline int 2007 _fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags) 2008 { 2009 struct file *fp; 2010 int error; 2011 2012 GIANT_REQUIRED; /* VFS */ 2013 2014 *vpp = NULL; 2015 if ((error = _fget(td, fd, &fp, 0, 0)) != 0) 2016 return (error); 2017 if (fp->f_vnode == NULL) { 2018 error = EINVAL; 2019 } else { 2020 *vpp = fp->f_vnode; 2021 vref(*vpp); 2022 } 2023 FILEDESC_UNLOCK(td->td_proc->p_fd); 2024 return (error); 2025 } 2026 2027 int 2028 fgetvp(struct thread *td, int fd, struct vnode **vpp) 2029 { 2030 2031 return (_fgetvp(td, fd, vpp, 0)); 2032 } 2033 2034 int 2035 fgetvp_read(struct thread *td, int fd, struct vnode **vpp) 2036 { 2037 2038 return (_fgetvp(td, fd, vpp, FREAD)); 2039 } 2040 2041 #ifdef notyet 2042 int 2043 fgetvp_write(struct thread *td, int fd, struct vnode **vpp) 2044 { 2045 2046 return (_fgetvp(td, fd, vpp, FWRITE)); 2047 } 2048 #endif 2049 2050 /* 2051 * Like fget() but loads the underlying socket, or returns an error if 2052 * the descriptor does not represent a socket. 2053 * 2054 * We bump the ref count on the returned socket. XXX Also obtain the SX 2055 * lock in the future. 2056 */ 2057 int 2058 fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp) 2059 { 2060 struct file *fp; 2061 int error; 2062 2063 NET_ASSERT_GIANT(); 2064 2065 *spp = NULL; 2066 if (fflagp != NULL) 2067 *fflagp = 0; 2068 if ((error = _fget(td, fd, &fp, 0, 0)) != 0) 2069 return (error); 2070 if (fp->f_type != DTYPE_SOCKET) { 2071 error = ENOTSOCK; 2072 } else { 2073 *spp = fp->f_data; 2074 if (fflagp) 2075 *fflagp = fp->f_flag; 2076 SOCK_LOCK(*spp); 2077 soref(*spp); 2078 SOCK_UNLOCK(*spp); 2079 } 2080 FILEDESC_UNLOCK(td->td_proc->p_fd); 2081 return (error); 2082 } 2083 2084 /* 2085 * Drop the reference count on the the socket and XXX release the SX lock in 2086 * the future. The last reference closes the socket. 2087 */ 2088 void 2089 fputsock(struct socket *so) 2090 { 2091 2092 NET_ASSERT_GIANT(); 2093 ACCEPT_LOCK(); 2094 SOCK_LOCK(so); 2095 sorele(so); 2096 } 2097 2098 int 2099 fdrop(struct file *fp, struct thread *td) 2100 { 2101 2102 FILE_LOCK(fp); 2103 return (fdrop_locked(fp, td)); 2104 } 2105 2106 /* 2107 * Drop reference on struct file passed in, may call closef if the 2108 * reference hits zero. 2109 * Expects struct file locked, and will unlock it. 2110 */ 2111 static int 2112 fdrop_locked(struct file *fp, struct thread *td) 2113 { 2114 int error; 2115 2116 FILE_LOCK_ASSERT(fp, MA_OWNED); 2117 2118 if (--fp->f_count > 0) { 2119 FILE_UNLOCK(fp); 2120 return (0); 2121 } 2122 /* We have the last ref so we can proceed without the file lock. */ 2123 FILE_UNLOCK(fp); 2124 if (fp->f_count < 0) 2125 panic("fdrop: count < 0"); 2126 if (fp->f_ops != &badfileops) 2127 error = fo_close(fp, td); 2128 else 2129 error = 0; 2130 2131 sx_xlock(&filelist_lock); 2132 LIST_REMOVE(fp, f_list); 2133 nfiles--; 2134 sx_xunlock(&filelist_lock); 2135 crfree(fp->f_cred); 2136 uma_zfree(file_zone, fp); 2137 2138 return (error); 2139 } 2140 2141 /* 2142 * Apply an advisory lock on a file descriptor. 2143 * 2144 * Just attempt to get a record lock of the requested type on 2145 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2146 */ 2147 #ifndef _SYS_SYSPROTO_H_ 2148 struct flock_args { 2149 int fd; 2150 int how; 2151 }; 2152 #endif 2153 /* 2154 * MPSAFE 2155 */ 2156 /* ARGSUSED */ 2157 int 2158 flock(struct thread *td, struct flock_args *uap) 2159 { 2160 struct file *fp; 2161 struct vnode *vp; 2162 struct flock lf; 2163 int error; 2164 2165 if ((error = fget(td, uap->fd, &fp)) != 0) 2166 return (error); 2167 if (fp->f_type != DTYPE_VNODE) { 2168 fdrop(fp, td); 2169 return (EOPNOTSUPP); 2170 } 2171 2172 mtx_lock(&Giant); 2173 vp = fp->f_vnode; 2174 lf.l_whence = SEEK_SET; 2175 lf.l_start = 0; 2176 lf.l_len = 0; 2177 if (uap->how & LOCK_UN) { 2178 lf.l_type = F_UNLCK; 2179 FILE_LOCK(fp); 2180 fp->f_flag &= ~FHASLOCK; 2181 FILE_UNLOCK(fp); 2182 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 2183 goto done2; 2184 } 2185 if (uap->how & LOCK_EX) 2186 lf.l_type = F_WRLCK; 2187 else if (uap->how & LOCK_SH) 2188 lf.l_type = F_RDLCK; 2189 else { 2190 error = EBADF; 2191 goto done2; 2192 } 2193 FILE_LOCK(fp); 2194 fp->f_flag |= FHASLOCK; 2195 FILE_UNLOCK(fp); 2196 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 2197 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT); 2198 done2: 2199 fdrop(fp, td); 2200 mtx_unlock(&Giant); 2201 return (error); 2202 } 2203 /* 2204 * Duplicate the specified descriptor to a free descriptor. 2205 */ 2206 int 2207 dupfdopen(struct thread *td, struct filedesc *fdp, int indx, int dfd, int mode, int error) 2208 { 2209 struct file *wfp; 2210 struct file *fp; 2211 2212 /* 2213 * If the to-be-dup'd fd number is greater than the allowed number 2214 * of file descriptors, or the fd to be dup'd has already been 2215 * closed, then reject. 2216 */ 2217 FILEDESC_LOCK(fdp); 2218 if (dfd < 0 || dfd >= fdp->fd_nfiles || 2219 (wfp = fdp->fd_ofiles[dfd]) == NULL) { 2220 FILEDESC_UNLOCK(fdp); 2221 return (EBADF); 2222 } 2223 2224 /* 2225 * There are two cases of interest here. 2226 * 2227 * For ENODEV simply dup (dfd) to file descriptor 2228 * (indx) and return. 2229 * 2230 * For ENXIO steal away the file structure from (dfd) and 2231 * store it in (indx). (dfd) is effectively closed by 2232 * this operation. 2233 * 2234 * Any other error code is just returned. 2235 */ 2236 switch (error) { 2237 case ENODEV: 2238 /* 2239 * Check that the mode the file is being opened for is a 2240 * subset of the mode of the existing descriptor. 2241 */ 2242 FILE_LOCK(wfp); 2243 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2244 FILE_UNLOCK(wfp); 2245 FILEDESC_UNLOCK(fdp); 2246 return (EACCES); 2247 } 2248 fp = fdp->fd_ofiles[indx]; 2249 fdp->fd_ofiles[indx] = wfp; 2250 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2251 if (fp == NULL) 2252 fdused(fdp, indx); 2253 fhold_locked(wfp); 2254 FILE_UNLOCK(wfp); 2255 FILEDESC_UNLOCK(fdp); 2256 if (fp != NULL) { 2257 /* 2258 * We now own the reference to fp that the ofiles[] 2259 * array used to own. Release it. 2260 */ 2261 FILE_LOCK(fp); 2262 fdrop_locked(fp, td); 2263 } 2264 return (0); 2265 2266 case ENXIO: 2267 /* 2268 * Steal away the file pointer from dfd and stuff it into indx. 2269 */ 2270 fp = fdp->fd_ofiles[indx]; 2271 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd]; 2272 fdp->fd_ofiles[dfd] = NULL; 2273 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2274 fdp->fd_ofileflags[dfd] = 0; 2275 fdunused(fdp, dfd); 2276 if (fp == NULL) 2277 fdused(fdp, indx); 2278 if (fp != NULL) 2279 FILE_LOCK(fp); 2280 FILEDESC_UNLOCK(fdp); 2281 2282 /* 2283 * we now own the reference to fp that the ofiles[] array 2284 * used to own. Release it. 2285 */ 2286 if (fp != NULL) 2287 fdrop_locked(fp, td); 2288 return (0); 2289 2290 default: 2291 FILEDESC_UNLOCK(fdp); 2292 return (error); 2293 } 2294 /* NOTREACHED */ 2295 } 2296 /* 2297 * Scan all active processes to see if any of them have a current 2298 * or root directory of `olddp'. If so, replace them with the new 2299 * mount point. 2300 */ 2301 void 2302 mountcheckdirs(struct vnode *olddp, struct vnode *newdp) 2303 { 2304 struct filedesc *fdp; 2305 struct proc *p; 2306 int nrele; 2307 2308 if (vrefcnt(olddp) == 1) 2309 return; 2310 sx_slock(&allproc_lock); 2311 LIST_FOREACH(p, &allproc, p_list) { 2312 fdp = fdhold(p); 2313 if (fdp == NULL) 2314 continue; 2315 nrele = 0; 2316 FILEDESC_LOCK_FAST(fdp); 2317 if (fdp->fd_cdir == olddp) { 2318 vref(newdp); 2319 fdp->fd_cdir = newdp; 2320 nrele++; 2321 } 2322 if (fdp->fd_rdir == olddp) { 2323 vref(newdp); 2324 fdp->fd_rdir = newdp; 2325 nrele++; 2326 } 2327 FILEDESC_UNLOCK_FAST(fdp); 2328 fddrop(fdp); 2329 while (nrele--) 2330 vrele(olddp); 2331 } 2332 sx_sunlock(&allproc_lock); 2333 if (rootvnode == olddp) { 2334 vrele(rootvnode); 2335 vref(newdp); 2336 rootvnode = newdp; 2337 } 2338 } 2339 2340 struct filedesc_to_leader * 2341 filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader) 2342 { 2343 struct filedesc_to_leader *fdtol; 2344 2345 MALLOC(fdtol, struct filedesc_to_leader *, 2346 sizeof(struct filedesc_to_leader), 2347 M_FILEDESC_TO_LEADER, 2348 M_WAITOK); 2349 fdtol->fdl_refcount = 1; 2350 fdtol->fdl_holdcount = 0; 2351 fdtol->fdl_wakeup = 0; 2352 fdtol->fdl_leader = leader; 2353 if (old != NULL) { 2354 FILEDESC_LOCK(fdp); 2355 fdtol->fdl_next = old->fdl_next; 2356 fdtol->fdl_prev = old; 2357 old->fdl_next = fdtol; 2358 fdtol->fdl_next->fdl_prev = fdtol; 2359 FILEDESC_UNLOCK(fdp); 2360 } else { 2361 fdtol->fdl_next = fdtol; 2362 fdtol->fdl_prev = fdtol; 2363 } 2364 return (fdtol); 2365 } 2366 2367 /* 2368 * Get file structures. 2369 */ 2370 static int 2371 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2372 { 2373 struct xfile xf; 2374 struct filedesc *fdp; 2375 struct file *fp; 2376 struct proc *p; 2377 int error, n; 2378 2379 /* 2380 * Note: because the number of file descriptors is calculated 2381 * in different ways for sizing vs returning the data, 2382 * there is information leakage from the first loop. However, 2383 * it is of a similar order of magnitude to the leakage from 2384 * global system statistics such as kern.openfiles. 2385 */ 2386 error = sysctl_wire_old_buffer(req, 0); 2387 if (error != 0) 2388 return (error); 2389 if (req->oldptr == NULL) { 2390 n = 16; /* A slight overestimate. */ 2391 sx_slock(&filelist_lock); 2392 LIST_FOREACH(fp, &filehead, f_list) { 2393 /* 2394 * We should grab the lock, but this is an 2395 * estimate, so does it really matter? 2396 */ 2397 /* mtx_lock(fp->f_mtxp); */ 2398 n += fp->f_count; 2399 /* mtx_unlock(f->f_mtxp); */ 2400 } 2401 sx_sunlock(&filelist_lock); 2402 return (SYSCTL_OUT(req, 0, n * sizeof(xf))); 2403 } 2404 error = 0; 2405 bzero(&xf, sizeof(xf)); 2406 xf.xf_size = sizeof(xf); 2407 sx_slock(&allproc_lock); 2408 LIST_FOREACH(p, &allproc, p_list) { 2409 if (p->p_state == PRS_NEW) 2410 continue; 2411 PROC_LOCK(p); 2412 if (p_cansee(req->td, p) != 0) { 2413 PROC_UNLOCK(p); 2414 continue; 2415 } 2416 xf.xf_pid = p->p_pid; 2417 xf.xf_uid = p->p_ucred->cr_uid; 2418 PROC_UNLOCK(p); 2419 fdp = fdhold(p); 2420 if (fdp == NULL) 2421 continue; 2422 FILEDESC_LOCK_FAST(fdp); 2423 for (n = 0; fdp->fd_refcnt > 0 && n < fdp->fd_nfiles; ++n) { 2424 if ((fp = fdp->fd_ofiles[n]) == NULL) 2425 continue; 2426 xf.xf_fd = n; 2427 xf.xf_file = fp; 2428 xf.xf_data = fp->f_data; 2429 xf.xf_vnode = fp->f_vnode; 2430 xf.xf_type = fp->f_type; 2431 xf.xf_count = fp->f_count; 2432 xf.xf_msgcount = fp->f_msgcount; 2433 xf.xf_offset = fp->f_offset; 2434 xf.xf_flag = fp->f_flag; 2435 error = SYSCTL_OUT(req, &xf, sizeof(xf)); 2436 if (error) 2437 break; 2438 } 2439 FILEDESC_UNLOCK_FAST(fdp); 2440 fddrop(fdp); 2441 if (error) 2442 break; 2443 } 2444 sx_sunlock(&allproc_lock); 2445 return (error); 2446 } 2447 2448 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2449 0, 0, sysctl_kern_file, "S,xfile", "Entire file table"); 2450 2451 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 2452 &maxfilesperproc, 0, "Maximum files allowed open per process"); 2453 2454 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 2455 &maxfiles, 0, "Maximum number of files"); 2456 2457 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 2458 &nfiles, 0, "System-wide number of open files"); 2459 2460 /* ARGSUSED*/ 2461 static void 2462 filelistinit(void *dummy) 2463 { 2464 2465 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL, 2466 NULL, NULL, UMA_ALIGN_PTR, 0); 2467 sx_init(&filelist_lock, "filelist lock"); 2468 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF); 2469 mtx_init(&fdesc_mtx, "fdesc", NULL, MTX_DEF); 2470 } 2471 SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL) 2472 2473 /*-------------------------------------------------------------------*/ 2474 2475 static int 2476 badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td) 2477 { 2478 2479 return (EBADF); 2480 } 2481 2482 static int 2483 badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, struct thread *td) 2484 { 2485 2486 return (EBADF); 2487 } 2488 2489 static int 2490 badfo_poll(struct file *fp, int events, struct ucred *active_cred, struct thread *td) 2491 { 2492 2493 return (0); 2494 } 2495 2496 static int 2497 badfo_kqfilter(struct file *fp, struct knote *kn) 2498 { 2499 2500 return (0); 2501 } 2502 2503 static int 2504 badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, struct thread *td) 2505 { 2506 2507 return (EBADF); 2508 } 2509 2510 static int 2511 badfo_close(struct file *fp, struct thread *td) 2512 { 2513 2514 return (EBADF); 2515 } 2516 2517 struct fileops badfileops = { 2518 .fo_read = badfo_readwrite, 2519 .fo_write = badfo_readwrite, 2520 .fo_ioctl = badfo_ioctl, 2521 .fo_poll = badfo_poll, 2522 .fo_kqfilter = badfo_kqfilter, 2523 .fo_stat = badfo_stat, 2524 .fo_close = badfo_close, 2525 }; 2526 2527 2528 /*-------------------------------------------------------------------*/ 2529 2530 /* 2531 * File Descriptor pseudo-device driver (/dev/fd/). 2532 * 2533 * Opening minor device N dup()s the file (if any) connected to file 2534 * descriptor N belonging to the calling process. Note that this driver 2535 * consists of only the ``open()'' routine, because all subsequent 2536 * references to this file will be direct to the other driver. 2537 * 2538 * XXX: we could give this one a cloning event handler if necessary. 2539 */ 2540 2541 /* ARGSUSED */ 2542 static int 2543 fdopen(struct cdev *dev, int mode, int type, struct thread *td) 2544 { 2545 2546 /* 2547 * XXX Kludge: set curthread->td_dupfd to contain the value of the 2548 * the file descriptor being sought for duplication. The error 2549 * return ensures that the vnode for this device will be released 2550 * by vn_open. Open will detect this special error and take the 2551 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 2552 * will simply report the error. 2553 */ 2554 td->td_dupfd = dev2unit(dev); 2555 return (ENODEV); 2556 } 2557 2558 static struct cdevsw fildesc_cdevsw = { 2559 .d_version = D_VERSION, 2560 .d_flags = D_NEEDGIANT, 2561 .d_open = fdopen, 2562 .d_name = "FD", 2563 }; 2564 2565 static void 2566 fildesc_drvinit(void *unused) 2567 { 2568 struct cdev *dev; 2569 2570 dev = make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "fd/0"); 2571 make_dev_alias(dev, "stdin"); 2572 dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1"); 2573 make_dev_alias(dev, "stdout"); 2574 dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2"); 2575 make_dev_alias(dev, "stderr"); 2576 } 2577 2578 SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL)
Cache object: 10d4578afea74e29b51732b1856c32b2
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