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("$FreeBSD$"); 39 40 #include "opt_compat.h" 41 42 #include <sys/param.h> 43 #include <sys/limits.h> 44 #include <sys/systm.h> 45 #include <sys/syscallsubr.h> 46 #include <sys/sysproto.h> 47 #include <sys/conf.h> 48 #include <sys/filedesc.h> 49 #include <sys/lock.h> 50 #include <sys/jail.h> 51 #include <sys/kernel.h> 52 #include <sys/limits.h> 53 #include <sys/malloc.h> 54 #include <sys/mutex.h> 55 #include <sys/sysctl.h> 56 #include <sys/vnode.h> 57 #include <sys/mount.h> 58 #include <sys/proc.h> 59 #include <sys/namei.h> 60 #include <sys/file.h> 61 #include <sys/stat.h> 62 #include <sys/filio.h> 63 #include <sys/fcntl.h> 64 #include <sys/unistd.h> 65 #include <sys/resourcevar.h> 66 #include <sys/event.h> 67 #include <sys/sx.h> 68 #include <sys/socketvar.h> 69 #include <sys/signalvar.h> 70 71 #include <vm/vm.h> 72 #include <vm/vm_extern.h> 73 #include <vm/uma.h> 74 75 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 76 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 77 "file desc to leader structures"); 78 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 79 80 static uma_zone_t file_zone; 81 82 static d_open_t fdopen; 83 #define NUMFDESC 64 84 85 #define CDEV_MAJOR 22 86 static struct cdevsw fildesc_cdevsw = { 87 .d_version = D_VERSION, 88 .d_flags = D_NEEDGIANT, 89 .d_open = fdopen, 90 .d_name = "FD", 91 .d_maj = CDEV_MAJOR, 92 }; 93 94 /* How to treat 'new' parameter when allocating a fd for do_dup(). */ 95 enum dup_type { DUP_VARIABLE, DUP_FIXED }; 96 97 static int do_dup(struct thread *td, enum dup_type type, int old, int new, 98 register_t *retval); 99 static int fd_first_free(struct filedesc *, int, int); 100 static int fd_last_used(struct filedesc *, int, int); 101 static void fdgrowtable(struct filedesc *, int); 102 103 /* 104 * Descriptor management. 105 */ 106 struct filelist filehead; /* head of list of open files */ 107 int nfiles; /* actual number of open files */ 108 struct sx filelist_lock; /* sx to protect filelist */ 109 struct mtx sigio_lock; /* mtx to protect pointers to sigio */ 110 111 /* 112 * Find the first zero bit in the given bitmap, starting at low and not 113 * exceeding size - 1. 114 */ 115 static int 116 fd_first_free(struct filedesc *fdp, int low, int size) 117 { 118 NDSLOTTYPE *map = fdp->fd_map; 119 NDSLOTTYPE mask; 120 int off, maxoff; 121 122 if (low >= size) 123 return (low); 124 125 off = NDSLOT(low); 126 if (low % NDENTRIES) { 127 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES))); 128 if ((mask &= ~map[off]) != 0UL) 129 return (off * NDENTRIES + ffsl(mask) - 1); 130 ++off; 131 } 132 for (maxoff = NDSLOTS(size); off < maxoff; ++off) 133 if (map[off] != ~0UL) 134 return (off * NDENTRIES + ffsl(~map[off]) - 1); 135 return (size); 136 } 137 138 /* 139 * Find the highest non-zero bit in the given bitmap, starting at low and 140 * not exceeding size - 1. 141 */ 142 static int 143 fd_last_used(struct filedesc *fdp, int low, int size) 144 { 145 NDSLOTTYPE *map = fdp->fd_map; 146 NDSLOTTYPE mask; 147 int off, minoff; 148 149 if (low >= size) 150 return (-1); 151 152 off = NDSLOT(size); 153 if (size % NDENTRIES) { 154 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES)); 155 if ((mask &= map[off]) != 0) 156 return (off * NDENTRIES + flsl(mask) - 1); 157 --off; 158 } 159 for (minoff = NDSLOT(low); off >= minoff; --off) 160 if (map[off] != 0) 161 return (off * NDENTRIES + flsl(map[off]) - 1); 162 return (size - 1); 163 } 164 165 static int 166 fdisused(struct filedesc *fdp, int fd) 167 { 168 KASSERT(fd >= 0 && fd < fdp->fd_nfiles, 169 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles)); 170 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0); 171 } 172 173 /* 174 * Mark a file descriptor as used. 175 */ 176 void 177 fdused(struct filedesc *fdp, int fd) 178 { 179 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 180 KASSERT(!fdisused(fdp, fd), 181 ("fd already used")); 182 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd); 183 if (fd > fdp->fd_lastfile) 184 fdp->fd_lastfile = fd; 185 if (fd == fdp->fd_freefile) 186 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 187 } 188 189 /* 190 * Mark a file descriptor as unused. 191 */ 192 void 193 fdunused(struct filedesc *fdp, int fd) 194 { 195 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 196 KASSERT(fdisused(fdp, fd), 197 ("fd is already unused")); 198 KASSERT(fdp->fd_ofiles[fd] == NULL, 199 ("fd is still in use")); 200 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd); 201 if (fd < fdp->fd_freefile) 202 fdp->fd_freefile = fd; 203 if (fd == fdp->fd_lastfile) 204 fdp->fd_lastfile = fd_last_used(fdp, 0, fd); 205 } 206 207 /* 208 * System calls on descriptors. 209 */ 210 #ifndef _SYS_SYSPROTO_H_ 211 struct getdtablesize_args { 212 int dummy; 213 }; 214 #endif 215 /* 216 * MPSAFE 217 */ 218 /* ARGSUSED */ 219 int 220 getdtablesize(td, uap) 221 struct thread *td; 222 struct getdtablesize_args *uap; 223 { 224 struct proc *p = td->td_proc; 225 226 PROC_LOCK(p); 227 td->td_retval[0] = 228 min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 229 PROC_UNLOCK(p); 230 return (0); 231 } 232 233 /* 234 * Duplicate a file descriptor to a particular value. 235 * 236 * note: keep in mind that a potential race condition exists when closing 237 * descriptors from a shared descriptor table (via rfork). 238 */ 239 #ifndef _SYS_SYSPROTO_H_ 240 struct dup2_args { 241 u_int from; 242 u_int to; 243 }; 244 #endif 245 /* 246 * MPSAFE 247 */ 248 /* ARGSUSED */ 249 int 250 dup2(td, uap) 251 struct thread *td; 252 struct dup2_args *uap; 253 { 254 255 return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to, 256 td->td_retval)); 257 } 258 259 /* 260 * Duplicate a file descriptor. 261 */ 262 #ifndef _SYS_SYSPROTO_H_ 263 struct dup_args { 264 u_int fd; 265 }; 266 #endif 267 /* 268 * MPSAFE 269 */ 270 /* ARGSUSED */ 271 int 272 dup(td, uap) 273 struct thread *td; 274 struct dup_args *uap; 275 { 276 277 return (do_dup(td, DUP_VARIABLE, (int)uap->fd, 0, td->td_retval)); 278 } 279 280 /* 281 * The file control system call. 282 */ 283 #ifndef _SYS_SYSPROTO_H_ 284 struct fcntl_args { 285 int fd; 286 int cmd; 287 long arg; 288 }; 289 #endif 290 /* 291 * MPSAFE 292 */ 293 /* ARGSUSED */ 294 int 295 fcntl(td, uap) 296 struct thread *td; 297 struct fcntl_args *uap; 298 { 299 struct flock fl; 300 intptr_t arg; 301 int error; 302 303 error = 0; 304 switch (uap->cmd) { 305 case F_GETLK: 306 case F_SETLK: 307 case F_SETLKW: 308 error = copyin((void *)(intptr_t)uap->arg, &fl, sizeof(fl)); 309 arg = (intptr_t)&fl; 310 break; 311 default: 312 arg = uap->arg; 313 break; 314 } 315 if (error) 316 return (error); 317 error = kern_fcntl(td, uap->fd, uap->cmd, arg); 318 if (error) 319 return (error); 320 if (uap->cmd == F_GETLK) 321 error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl)); 322 return (error); 323 } 324 325 int 326 kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) 327 { 328 struct filedesc *fdp; 329 struct flock *flp; 330 struct file *fp; 331 struct proc *p; 332 char *pop; 333 struct vnode *vp; 334 u_int newmin; 335 int error, flg, tmp; 336 int giant_locked; 337 338 /* 339 * XXXRW: Some fcntl() calls require Giant -- others don't. Try to 340 * avoid grabbing Giant for calls we know don't need it. 341 */ 342 switch (cmd) { 343 case F_DUPFD: 344 case F_GETFD: 345 case F_SETFD: 346 case F_GETFL: 347 giant_locked = 0; 348 break; 349 350 default: 351 giant_locked = 1; 352 mtx_lock(&Giant); 353 } 354 355 error = 0; 356 flg = F_POSIX; 357 p = td->td_proc; 358 fdp = p->p_fd; 359 FILEDESC_LOCK(fdp); 360 if ((unsigned)fd >= fdp->fd_nfiles || 361 (fp = fdp->fd_ofiles[fd]) == NULL) { 362 FILEDESC_UNLOCK(fdp); 363 error = EBADF; 364 goto done2; 365 } 366 pop = &fdp->fd_ofileflags[fd]; 367 368 switch (cmd) { 369 case F_DUPFD: 370 /* mtx_assert(&Giant, MA_NOTOWNED); */ 371 FILEDESC_UNLOCK(fdp); 372 newmin = arg; 373 PROC_LOCK(p); 374 if (newmin >= lim_cur(p, RLIMIT_NOFILE) || 375 newmin >= maxfilesperproc) { 376 PROC_UNLOCK(p); 377 error = EINVAL; 378 break; 379 } 380 PROC_UNLOCK(p); 381 error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval); 382 break; 383 384 case F_GETFD: 385 /* mtx_assert(&Giant, MA_NOTOWNED); */ 386 td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0; 387 FILEDESC_UNLOCK(fdp); 388 break; 389 390 case F_SETFD: 391 /* mtx_assert(&Giant, MA_NOTOWNED); */ 392 *pop = (*pop &~ UF_EXCLOSE) | 393 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0); 394 FILEDESC_UNLOCK(fdp); 395 break; 396 397 case F_GETFL: 398 /* mtx_assert(&Giant, MA_NOTOWNED); */ 399 FILE_LOCK(fp); 400 FILEDESC_UNLOCK(fdp); 401 td->td_retval[0] = OFLAGS(fp->f_flag); 402 FILE_UNLOCK(fp); 403 break; 404 405 case F_SETFL: 406 mtx_assert(&Giant, MA_OWNED); 407 FILE_LOCK(fp); 408 FILEDESC_UNLOCK(fdp); 409 fhold_locked(fp); 410 fp->f_flag &= ~FCNTLFLAGS; 411 fp->f_flag |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS; 412 FILE_UNLOCK(fp); 413 tmp = fp->f_flag & FNONBLOCK; 414 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 415 if (error) { 416 fdrop(fp, td); 417 break; 418 } 419 tmp = fp->f_flag & FASYNC; 420 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); 421 if (error == 0) { 422 fdrop(fp, td); 423 break; 424 } 425 FILE_LOCK(fp); 426 fp->f_flag &= ~FNONBLOCK; 427 FILE_UNLOCK(fp); 428 tmp = 0; 429 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 430 fdrop(fp, td); 431 break; 432 433 case F_GETOWN: 434 mtx_assert(&Giant, MA_OWNED); 435 fhold(fp); 436 FILEDESC_UNLOCK(fdp); 437 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td); 438 if (error == 0) 439 td->td_retval[0] = tmp; 440 fdrop(fp, td); 441 break; 442 443 case F_SETOWN: 444 mtx_assert(&Giant, MA_OWNED); 445 fhold(fp); 446 FILEDESC_UNLOCK(fdp); 447 tmp = arg; 448 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td); 449 fdrop(fp, td); 450 break; 451 452 case F_SETLKW: 453 mtx_assert(&Giant, MA_OWNED); 454 flg |= F_WAIT; 455 /* FALLTHROUGH F_SETLK */ 456 457 case F_SETLK: 458 mtx_assert(&Giant, MA_OWNED); 459 if (fp->f_type != DTYPE_VNODE) { 460 FILEDESC_UNLOCK(fdp); 461 error = EBADF; 462 break; 463 } 464 465 flp = (struct flock *)arg; 466 if (flp->l_whence == SEEK_CUR) { 467 if (fp->f_offset < 0 || 468 (flp->l_start > 0 && 469 fp->f_offset > OFF_MAX - flp->l_start)) { 470 FILEDESC_UNLOCK(fdp); 471 error = EOVERFLOW; 472 break; 473 } 474 flp->l_start += fp->f_offset; 475 } 476 477 /* 478 * VOP_ADVLOCK() may block. 479 */ 480 fhold(fp); 481 FILEDESC_UNLOCK(fdp); 482 vp = fp->f_vnode; 483 484 switch (flp->l_type) { 485 case F_RDLCK: 486 if ((fp->f_flag & FREAD) == 0) { 487 error = EBADF; 488 break; 489 } 490 PROC_LOCK(p->p_leader); 491 p->p_leader->p_flag |= P_ADVLOCK; 492 PROC_UNLOCK(p->p_leader); 493 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 494 flp, flg); 495 break; 496 case F_WRLCK: 497 if ((fp->f_flag & FWRITE) == 0) { 498 error = EBADF; 499 break; 500 } 501 PROC_LOCK(p->p_leader); 502 p->p_leader->p_flag |= P_ADVLOCK; 503 PROC_UNLOCK(p->p_leader); 504 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 505 flp, flg); 506 break; 507 case F_UNLCK: 508 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 509 flp, F_POSIX); 510 break; 511 default: 512 error = EINVAL; 513 break; 514 } 515 /* Check for race with close */ 516 FILEDESC_LOCK(fdp); 517 if ((unsigned) fd >= fdp->fd_nfiles || 518 fp != fdp->fd_ofiles[fd]) { 519 FILEDESC_UNLOCK(fdp); 520 flp->l_whence = SEEK_SET; 521 flp->l_start = 0; 522 flp->l_len = 0; 523 flp->l_type = F_UNLCK; 524 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 525 F_UNLCK, flp, F_POSIX); 526 } else 527 FILEDESC_UNLOCK(fdp); 528 fdrop(fp, td); 529 break; 530 531 case F_GETLK: 532 mtx_assert(&Giant, MA_OWNED); 533 if (fp->f_type != DTYPE_VNODE) { 534 FILEDESC_UNLOCK(fdp); 535 error = EBADF; 536 break; 537 } 538 flp = (struct flock *)arg; 539 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK && 540 flp->l_type != F_UNLCK) { 541 FILEDESC_UNLOCK(fdp); 542 error = EINVAL; 543 break; 544 } 545 if (flp->l_whence == SEEK_CUR) { 546 if ((flp->l_start > 0 && 547 fp->f_offset > OFF_MAX - flp->l_start) || 548 (flp->l_start < 0 && 549 fp->f_offset < OFF_MIN - flp->l_start)) { 550 FILEDESC_UNLOCK(fdp); 551 error = EOVERFLOW; 552 break; 553 } 554 flp->l_start += fp->f_offset; 555 } 556 /* 557 * VOP_ADVLOCK() may block. 558 */ 559 fhold(fp); 560 FILEDESC_UNLOCK(fdp); 561 vp = fp->f_vnode; 562 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp, 563 F_POSIX); 564 fdrop(fp, td); 565 break; 566 default: 567 FILEDESC_UNLOCK(fdp); 568 error = EINVAL; 569 break; 570 } 571 done2: 572 if (giant_locked) 573 mtx_unlock(&Giant); 574 return (error); 575 } 576 577 /* 578 * Common code for dup, dup2, and fcntl(F_DUPFD). 579 */ 580 static int 581 do_dup(td, type, old, new, retval) 582 enum dup_type type; 583 int old, new; 584 register_t *retval; 585 struct thread *td; 586 { 587 struct filedesc *fdp; 588 struct proc *p; 589 struct file *fp; 590 struct file *delfp; 591 int error, holdleaders, maxfd; 592 593 KASSERT((type == DUP_VARIABLE || type == DUP_FIXED), 594 ("invalid dup type %d", type)); 595 596 p = td->td_proc; 597 fdp = p->p_fd; 598 599 /* 600 * Verify we have a valid descriptor to dup from and possibly to 601 * dup to. 602 */ 603 if (old < 0 || new < 0) 604 return (EBADF); 605 PROC_LOCK(p); 606 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 607 PROC_UNLOCK(p); 608 if (new >= maxfd) 609 return (EMFILE); 610 611 FILEDESC_LOCK(fdp); 612 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) { 613 FILEDESC_UNLOCK(fdp); 614 return (EBADF); 615 } 616 if (type == DUP_FIXED && old == new) { 617 *retval = new; 618 FILEDESC_UNLOCK(fdp); 619 return (0); 620 } 621 fp = fdp->fd_ofiles[old]; 622 fhold(fp); 623 624 /* 625 * If the caller specified a file descriptor, make sure the file 626 * table is large enough to hold it, and grab it. Otherwise, just 627 * allocate a new descriptor the usual way. Since the filedesc 628 * lock may be temporarily dropped in the process, we have to look 629 * out for a race. 630 */ 631 if (type == DUP_FIXED) { 632 if (new >= fdp->fd_nfiles) 633 fdgrowtable(fdp, new + 1); 634 if (fdp->fd_ofiles[new] == NULL) 635 fdused(fdp, new); 636 } else { 637 if ((error = fdalloc(td, new, &new)) != 0) { 638 FILEDESC_UNLOCK(fdp); 639 fdrop(fp, td); 640 return (error); 641 } 642 } 643 644 /* 645 * If the old file changed out from under us then treat it as a 646 * bad file descriptor. Userland should do its own locking to 647 * avoid this case. 648 */ 649 if (fdp->fd_ofiles[old] != fp) { 650 /* we've allocated a descriptor which we won't use */ 651 if (fdp->fd_ofiles[new] == NULL) 652 fdunused(fdp, new); 653 FILEDESC_UNLOCK(fdp); 654 fdrop(fp, td); 655 return (EBADF); 656 } 657 KASSERT(old != new, 658 ("new fd is same as old")); 659 660 /* 661 * Save info on the descriptor being overwritten. We cannot close 662 * it without introducing an ownership race for the slot, since we 663 * need to drop the filedesc lock to call closef(). 664 * 665 * XXX this duplicates parts of close(). 666 */ 667 delfp = fdp->fd_ofiles[new]; 668 holdleaders = 0; 669 if (delfp != NULL) { 670 if (td->td_proc->p_fdtol != NULL) { 671 /* 672 * Ask fdfree() to sleep to ensure that all relevant 673 * process leaders can be traversed in closef(). 674 */ 675 fdp->fd_holdleaderscount++; 676 holdleaders = 1; 677 } 678 } 679 680 /* 681 * Duplicate the source descriptor 682 */ 683 fdp->fd_ofiles[new] = fp; 684 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE; 685 if (new > fdp->fd_lastfile) 686 fdp->fd_lastfile = new; 687 *retval = new; 688 689 /* 690 * If we dup'd over a valid file, we now own the reference to it 691 * and must dispose of it using closef() semantics (as if a 692 * close() were performed on it). 693 * 694 * XXX this duplicates parts of close(). 695 */ 696 if (delfp != NULL) { 697 knote_fdclose(td, new); 698 FILEDESC_UNLOCK(fdp); 699 mtx_lock(&Giant); 700 (void) closef(delfp, td); 701 mtx_unlock(&Giant); 702 if (holdleaders) { 703 FILEDESC_LOCK(fdp); 704 fdp->fd_holdleaderscount--; 705 if (fdp->fd_holdleaderscount == 0 && 706 fdp->fd_holdleaderswakeup != 0) { 707 fdp->fd_holdleaderswakeup = 0; 708 wakeup(&fdp->fd_holdleaderscount); 709 } 710 FILEDESC_UNLOCK(fdp); 711 } 712 } else { 713 FILEDESC_UNLOCK(fdp); 714 } 715 return (0); 716 } 717 718 /* 719 * If sigio is on the list associated with a process or process group, 720 * disable signalling from the device, remove sigio from the list and 721 * free sigio. 722 */ 723 void 724 funsetown(sigiop) 725 struct sigio **sigiop; 726 { 727 struct sigio *sigio; 728 729 SIGIO_LOCK(); 730 sigio = *sigiop; 731 if (sigio == NULL) { 732 SIGIO_UNLOCK(); 733 return; 734 } 735 *(sigio->sio_myref) = NULL; 736 if ((sigio)->sio_pgid < 0) { 737 struct pgrp *pg = (sigio)->sio_pgrp; 738 PGRP_LOCK(pg); 739 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 740 sigio, sio_pgsigio); 741 PGRP_UNLOCK(pg); 742 } else { 743 struct proc *p = (sigio)->sio_proc; 744 PROC_LOCK(p); 745 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 746 sigio, sio_pgsigio); 747 PROC_UNLOCK(p); 748 } 749 SIGIO_UNLOCK(); 750 crfree(sigio->sio_ucred); 751 FREE(sigio, M_SIGIO); 752 } 753 754 /* 755 * Free a list of sigio structures. 756 * We only need to lock the SIGIO_LOCK because we have made ourselves 757 * inaccessable to callers of fsetown and therefore do not need to lock 758 * the proc or pgrp struct for the list manipulation. 759 */ 760 void 761 funsetownlst(sigiolst) 762 struct sigiolst *sigiolst; 763 { 764 struct proc *p; 765 struct pgrp *pg; 766 struct sigio *sigio; 767 768 sigio = SLIST_FIRST(sigiolst); 769 if (sigio == NULL) 770 return; 771 p = NULL; 772 pg = NULL; 773 774 /* 775 * Every entry of the list should belong 776 * to a single proc or pgrp. 777 */ 778 if (sigio->sio_pgid < 0) { 779 pg = sigio->sio_pgrp; 780 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED); 781 } else /* if (sigio->sio_pgid > 0) */ { 782 p = sigio->sio_proc; 783 PROC_LOCK_ASSERT(p, MA_NOTOWNED); 784 } 785 786 SIGIO_LOCK(); 787 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) { 788 *(sigio->sio_myref) = NULL; 789 if (pg != NULL) { 790 KASSERT(sigio->sio_pgid < 0, 791 ("Proc sigio in pgrp sigio list")); 792 KASSERT(sigio->sio_pgrp == pg, 793 ("Bogus pgrp in sigio list")); 794 PGRP_LOCK(pg); 795 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio, 796 sio_pgsigio); 797 PGRP_UNLOCK(pg); 798 } else /* if (p != NULL) */ { 799 KASSERT(sigio->sio_pgid > 0, 800 ("Pgrp sigio in proc sigio list")); 801 KASSERT(sigio->sio_proc == p, 802 ("Bogus proc in sigio list")); 803 PROC_LOCK(p); 804 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, 805 sio_pgsigio); 806 PROC_UNLOCK(p); 807 } 808 SIGIO_UNLOCK(); 809 crfree(sigio->sio_ucred); 810 FREE(sigio, M_SIGIO); 811 SIGIO_LOCK(); 812 } 813 SIGIO_UNLOCK(); 814 } 815 816 /* 817 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 818 * 819 * After permission checking, add a sigio structure to the sigio list for 820 * the process or process group. 821 */ 822 int 823 fsetown(pgid, sigiop) 824 pid_t pgid; 825 struct sigio **sigiop; 826 { 827 struct proc *proc; 828 struct pgrp *pgrp; 829 struct sigio *sigio; 830 int ret; 831 832 if (pgid == 0) { 833 funsetown(sigiop); 834 return (0); 835 } 836 837 ret = 0; 838 839 /* Allocate and fill in the new sigio out of locks. */ 840 MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK); 841 sigio->sio_pgid = pgid; 842 sigio->sio_ucred = crhold(curthread->td_ucred); 843 sigio->sio_myref = sigiop; 844 845 sx_slock(&proctree_lock); 846 if (pgid > 0) { 847 proc = pfind(pgid); 848 if (proc == NULL) { 849 ret = ESRCH; 850 goto fail; 851 } 852 853 /* 854 * Policy - Don't allow a process to FSETOWN a process 855 * in another session. 856 * 857 * Remove this test to allow maximum flexibility or 858 * restrict FSETOWN to the current process or process 859 * group for maximum safety. 860 */ 861 PROC_UNLOCK(proc); 862 if (proc->p_session != curthread->td_proc->p_session) { 863 ret = EPERM; 864 goto fail; 865 } 866 867 pgrp = NULL; 868 } else /* if (pgid < 0) */ { 869 pgrp = pgfind(-pgid); 870 if (pgrp == NULL) { 871 ret = ESRCH; 872 goto fail; 873 } 874 PGRP_UNLOCK(pgrp); 875 876 /* 877 * Policy - Don't allow a process to FSETOWN a process 878 * in another session. 879 * 880 * Remove this test to allow maximum flexibility or 881 * restrict FSETOWN to the current process or process 882 * group for maximum safety. 883 */ 884 if (pgrp->pg_session != curthread->td_proc->p_session) { 885 ret = EPERM; 886 goto fail; 887 } 888 889 proc = NULL; 890 } 891 funsetown(sigiop); 892 if (pgid > 0) { 893 PROC_LOCK(proc); 894 /* 895 * Since funsetownlst() is called without the proctree 896 * locked, we need to check for P_WEXIT. 897 * XXX: is ESRCH correct? 898 */ 899 if ((proc->p_flag & P_WEXIT) != 0) { 900 PROC_UNLOCK(proc); 901 ret = ESRCH; 902 goto fail; 903 } 904 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 905 sigio->sio_proc = proc; 906 PROC_UNLOCK(proc); 907 } else { 908 PGRP_LOCK(pgrp); 909 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 910 sigio->sio_pgrp = pgrp; 911 PGRP_UNLOCK(pgrp); 912 } 913 sx_sunlock(&proctree_lock); 914 SIGIO_LOCK(); 915 *sigiop = sigio; 916 SIGIO_UNLOCK(); 917 return (0); 918 919 fail: 920 sx_sunlock(&proctree_lock); 921 crfree(sigio->sio_ucred); 922 FREE(sigio, M_SIGIO); 923 return (ret); 924 } 925 926 /* 927 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 928 */ 929 pid_t 930 fgetown(sigiop) 931 struct sigio **sigiop; 932 { 933 pid_t pgid; 934 935 SIGIO_LOCK(); 936 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0; 937 SIGIO_UNLOCK(); 938 return (pgid); 939 } 940 941 /* 942 * Close a file descriptor. 943 */ 944 #ifndef _SYS_SYSPROTO_H_ 945 struct close_args { 946 int fd; 947 }; 948 #endif 949 /* 950 * MPSAFE 951 */ 952 /* ARGSUSED */ 953 int 954 close(td, uap) 955 struct thread *td; 956 struct close_args *uap; 957 { 958 struct filedesc *fdp; 959 struct file *fp; 960 int fd, error; 961 int holdleaders; 962 963 fd = uap->fd; 964 error = 0; 965 holdleaders = 0; 966 fdp = td->td_proc->p_fd; 967 mtx_lock(&Giant); 968 FILEDESC_LOCK(fdp); 969 if ((unsigned)fd >= fdp->fd_nfiles || 970 (fp = fdp->fd_ofiles[fd]) == NULL) { 971 FILEDESC_UNLOCK(fdp); 972 mtx_unlock(&Giant); 973 return (EBADF); 974 } 975 fdp->fd_ofiles[fd] = NULL; 976 fdp->fd_ofileflags[fd] = 0; 977 fdunused(fdp, fd); 978 if (td->td_proc->p_fdtol != NULL) { 979 /* 980 * Ask fdfree() to sleep to ensure that all relevant 981 * process leaders can be traversed in closef(). 982 */ 983 fdp->fd_holdleaderscount++; 984 holdleaders = 1; 985 } 986 987 /* 988 * we now hold the fp reference that used to be owned by the descriptor 989 * array. 990 * We have to unlock the FILEDESC *AFTER* knote_fdclose to prevent a 991 * race of the fd getting opened, a knote added, and deleteing a knote 992 * for the new fd. 993 */ 994 knote_fdclose(td, fd); 995 FILEDESC_UNLOCK(fdp); 996 997 error = closef(fp, td); 998 mtx_unlock(&Giant); 999 if (holdleaders) { 1000 FILEDESC_LOCK(fdp); 1001 fdp->fd_holdleaderscount--; 1002 if (fdp->fd_holdleaderscount == 0 && 1003 fdp->fd_holdleaderswakeup != 0) { 1004 fdp->fd_holdleaderswakeup = 0; 1005 wakeup(&fdp->fd_holdleaderscount); 1006 } 1007 FILEDESC_UNLOCK(fdp); 1008 } 1009 return (error); 1010 } 1011 1012 #if defined(COMPAT_43) 1013 /* 1014 * Return status information about a file descriptor. 1015 */ 1016 #ifndef _SYS_SYSPROTO_H_ 1017 struct ofstat_args { 1018 int fd; 1019 struct ostat *sb; 1020 }; 1021 #endif 1022 /* 1023 * MPSAFE 1024 */ 1025 /* ARGSUSED */ 1026 int 1027 ofstat(td, uap) 1028 struct thread *td; 1029 struct ofstat_args *uap; 1030 { 1031 struct file *fp; 1032 struct stat ub; 1033 struct ostat oub; 1034 int error; 1035 1036 if ((error = fget(td, uap->fd, &fp)) != 0) 1037 goto done2; 1038 error = fo_stat(fp, &ub, td->td_ucred, td); 1039 if (error == 0) { 1040 cvtstat(&ub, &oub); 1041 error = copyout(&oub, uap->sb, sizeof(oub)); 1042 } 1043 fdrop(fp, td); 1044 done2: 1045 return (error); 1046 } 1047 #endif /* COMPAT_43 */ 1048 1049 /* 1050 * Return status information about a file descriptor. 1051 */ 1052 #ifndef _SYS_SYSPROTO_H_ 1053 struct fstat_args { 1054 int fd; 1055 struct stat *sb; 1056 }; 1057 #endif 1058 /* 1059 * MPSAFE 1060 */ 1061 /* ARGSUSED */ 1062 int 1063 fstat(td, uap) 1064 struct thread *td; 1065 struct fstat_args *uap; 1066 { 1067 struct file *fp; 1068 struct stat ub; 1069 int error; 1070 1071 if ((error = fget(td, uap->fd, &fp)) != 0) 1072 goto done2; 1073 error = fo_stat(fp, &ub, td->td_ucred, td); 1074 if (error == 0) 1075 error = copyout(&ub, uap->sb, sizeof(ub)); 1076 fdrop(fp, td); 1077 done2: 1078 return (error); 1079 } 1080 1081 /* 1082 * Return status information about a file descriptor. 1083 */ 1084 #ifndef _SYS_SYSPROTO_H_ 1085 struct nfstat_args { 1086 int fd; 1087 struct nstat *sb; 1088 }; 1089 #endif 1090 /* 1091 * MPSAFE 1092 */ 1093 /* ARGSUSED */ 1094 int 1095 nfstat(td, uap) 1096 struct thread *td; 1097 struct nfstat_args *uap; 1098 { 1099 struct file *fp; 1100 struct stat ub; 1101 struct nstat nub; 1102 int error; 1103 1104 if ((error = fget(td, uap->fd, &fp)) != 0) 1105 goto done2; 1106 error = fo_stat(fp, &ub, td->td_ucred, td); 1107 if (error == 0) { 1108 cvtnstat(&ub, &nub); 1109 error = copyout(&nub, uap->sb, sizeof(nub)); 1110 } 1111 fdrop(fp, td); 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(td, uap) 1131 struct thread *td; 1132 struct fpathconf_args *uap; 1133 { 1134 struct file *fp; 1135 struct vnode *vp; 1136 int error; 1137 1138 if ((error = fget(td, uap->fd, &fp)) != 0) 1139 return (error); 1140 1141 /* If asynchronous I/O is available, it works for all descriptors. */ 1142 if (uap->name == _PC_ASYNC_IO) { 1143 td->td_retval[0] = async_io_version; 1144 goto out; 1145 } 1146 vp = fp->f_vnode; 1147 if (vp != NULL) { 1148 mtx_lock(&Giant); 1149 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 1150 error = VOP_PATHCONF(vp, uap->name, td->td_retval); 1151 VOP_UNLOCK(vp, 0, td); 1152 mtx_unlock(&Giant); 1153 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) { 1154 if (uap->name != _PC_PIPE_BUF) { 1155 error = EINVAL; 1156 } else { 1157 td->td_retval[0] = PIPE_BUF; 1158 error = 0; 1159 } 1160 } else { 1161 error = EOPNOTSUPP; 1162 } 1163 out: 1164 fdrop(fp, td); 1165 return (error); 1166 } 1167 1168 /* 1169 * Grow the file table to accomodate (at least) nfd descriptors. This may 1170 * block and drop the filedesc lock, but it will reacquire it before 1171 * returing. 1172 */ 1173 static void 1174 fdgrowtable(struct filedesc *fdp, int nfd) 1175 { 1176 struct file **ntable; 1177 char *nfileflags; 1178 int nnfiles, onfiles; 1179 NDSLOTTYPE *nmap; 1180 1181 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1182 1183 KASSERT(fdp->fd_nfiles > 0, 1184 ("zero-length file table")); 1185 1186 /* compute the size of the new table */ 1187 onfiles = fdp->fd_nfiles; 1188 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */ 1189 if (nnfiles <= onfiles) 1190 /* the table is already large enough */ 1191 return; 1192 1193 /* allocate a new table and (if required) new bitmaps */ 1194 FILEDESC_UNLOCK(fdp); 1195 MALLOC(ntable, struct file **, nnfiles * OFILESIZE, 1196 M_FILEDESC, M_ZERO | M_WAITOK); 1197 nfileflags = (char *)&ntable[nnfiles]; 1198 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) 1199 MALLOC(nmap, NDSLOTTYPE *, NDSLOTS(nnfiles) * NDSLOTSIZE, 1200 M_FILEDESC, M_ZERO | M_WAITOK); 1201 else 1202 nmap = NULL; 1203 FILEDESC_LOCK(fdp); 1204 1205 /* 1206 * We now have new tables ready to go. Since we dropped the 1207 * filedesc lock to call malloc(), watch out for a race. 1208 */ 1209 onfiles = fdp->fd_nfiles; 1210 if (onfiles >= nnfiles) { 1211 /* we lost the race, but that's OK */ 1212 free(ntable, M_FILEDESC); 1213 if (nmap != NULL) 1214 free(nmap, M_FILEDESC); 1215 return; 1216 } 1217 bcopy(fdp->fd_ofiles, ntable, onfiles * sizeof(*ntable)); 1218 bcopy(fdp->fd_ofileflags, nfileflags, onfiles); 1219 if (onfiles > NDFILE) 1220 free(fdp->fd_ofiles, M_FILEDESC); 1221 fdp->fd_ofiles = ntable; 1222 fdp->fd_ofileflags = nfileflags; 1223 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) { 1224 bcopy(fdp->fd_map, nmap, NDSLOTS(onfiles) * sizeof(*nmap)); 1225 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE)) 1226 free(fdp->fd_map, M_FILEDESC); 1227 fdp->fd_map = nmap; 1228 } 1229 fdp->fd_nfiles = nnfiles; 1230 } 1231 1232 /* 1233 * Allocate a file descriptor for the process. 1234 */ 1235 int 1236 fdalloc(struct thread *td, int minfd, int *result) 1237 { 1238 struct proc *p = td->td_proc; 1239 struct filedesc *fdp = p->p_fd; 1240 int fd = -1, maxfd; 1241 1242 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1243 1244 PROC_LOCK(p); 1245 maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1246 PROC_UNLOCK(p); 1247 1248 /* 1249 * Search the bitmap for a free descriptor. If none is found, try 1250 * to grow the file table. Keep at it until we either get a file 1251 * descriptor or run into process or system limits; fdgrowtable() 1252 * may drop the filedesc lock, so we're in a race. 1253 */ 1254 for (;;) { 1255 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); 1256 if (fd >= maxfd) 1257 return (EMFILE); 1258 if (fd < fdp->fd_nfiles) 1259 break; 1260 fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd)); 1261 } 1262 1263 /* 1264 * Perform some sanity checks, then mark the file descriptor as 1265 * used and return it to the caller. 1266 */ 1267 KASSERT(!fdisused(fdp, fd), 1268 ("fd_first_free() returned non-free descriptor")); 1269 KASSERT(fdp->fd_ofiles[fd] == NULL, 1270 ("free descriptor isn't")); 1271 fdp->fd_ofileflags[fd] = 0; /* XXX needed? */ 1272 fdused(fdp, fd); 1273 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 1274 *result = fd; 1275 return (0); 1276 } 1277 1278 /* 1279 * Check to see whether n user file descriptors 1280 * are available to the process p. 1281 */ 1282 int 1283 fdavail(td, n) 1284 struct thread *td; 1285 int n; 1286 { 1287 struct proc *p = td->td_proc; 1288 struct filedesc *fdp = td->td_proc->p_fd; 1289 struct file **fpp; 1290 int i, lim, last; 1291 1292 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1293 1294 PROC_LOCK(p); 1295 lim = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); 1296 PROC_UNLOCK(p); 1297 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) 1298 return (1); 1299 last = min(fdp->fd_nfiles, lim); 1300 fpp = &fdp->fd_ofiles[fdp->fd_freefile]; 1301 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) { 1302 if (*fpp == NULL && --n <= 0) 1303 return (1); 1304 } 1305 return (0); 1306 } 1307 1308 /* 1309 * Create a new open file structure and allocate 1310 * a file decriptor for the process that refers to it. 1311 * We add one reference to the file for the descriptor table 1312 * and one reference for resultfp. This is to prevent us being 1313 * prempted and the entry in the descriptor table closed after 1314 * we release the FILEDESC lock. 1315 */ 1316 int 1317 falloc(td, resultfp, resultfd) 1318 struct thread *td; 1319 struct file **resultfp; 1320 int *resultfd; 1321 { 1322 struct proc *p = td->td_proc; 1323 struct file *fp, *fq; 1324 int error, i; 1325 int maxuserfiles = maxfiles - (maxfiles / 20); 1326 static struct timeval lastfail; 1327 static int curfail; 1328 1329 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO); 1330 sx_xlock(&filelist_lock); 1331 if ((nfiles >= maxuserfiles && (td->td_ucred->cr_ruid != 0 || 1332 jailed(td->td_ucred))) || nfiles >= maxfiles) { 1333 if (ppsratecheck(&lastfail, &curfail, 1)) { 1334 printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n", 1335 td->td_ucred->cr_ruid); 1336 } 1337 sx_xunlock(&filelist_lock); 1338 uma_zfree(file_zone, fp); 1339 return (ENFILE); 1340 } 1341 nfiles++; 1342 1343 /* 1344 * If the process has file descriptor zero open, add the new file 1345 * descriptor to the list of open files at that point, otherwise 1346 * put it at the front of the list of open files. 1347 */ 1348 fp->f_mtxp = mtx_pool_alloc(mtxpool_sleep); 1349 fp->f_count = 1; 1350 if (resultfp) 1351 fp->f_count++; 1352 fp->f_cred = crhold(td->td_ucred); 1353 fp->f_ops = &badfileops; 1354 fp->f_data = NULL; 1355 fp->f_vnode = NULL; 1356 FILEDESC_LOCK(p->p_fd); 1357 if ((fq = p->p_fd->fd_ofiles[0])) { 1358 LIST_INSERT_AFTER(fq, fp, f_list); 1359 } else { 1360 LIST_INSERT_HEAD(&filehead, fp, f_list); 1361 } 1362 sx_xunlock(&filelist_lock); 1363 if ((error = fdalloc(td, 0, &i))) { 1364 FILEDESC_UNLOCK(p->p_fd); 1365 fdrop(fp, td); 1366 if (resultfp) 1367 fdrop(fp, td); 1368 return (error); 1369 } 1370 p->p_fd->fd_ofiles[i] = fp; 1371 FILEDESC_UNLOCK(p->p_fd); 1372 if (resultfp) 1373 *resultfp = fp; 1374 if (resultfd) 1375 *resultfd = i; 1376 return (0); 1377 } 1378 1379 /* 1380 * Free a file descriptor. 1381 */ 1382 void 1383 ffree(fp) 1384 struct file *fp; 1385 { 1386 1387 KASSERT(fp->f_count == 0, ("ffree: fp_fcount not 0!")); 1388 sx_xlock(&filelist_lock); 1389 LIST_REMOVE(fp, f_list); 1390 nfiles--; 1391 sx_xunlock(&filelist_lock); 1392 crfree(fp->f_cred); 1393 uma_zfree(file_zone, fp); 1394 } 1395 1396 /* 1397 * Build a new filedesc structure from another. 1398 * Copy the current, root, and jail root vnode references. 1399 */ 1400 struct filedesc * 1401 fdinit(fdp) 1402 struct filedesc *fdp; 1403 { 1404 struct filedesc0 *newfdp; 1405 1406 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1407 1408 FILEDESC_UNLOCK(fdp); 1409 MALLOC(newfdp, struct filedesc0 *, sizeof(struct filedesc0), 1410 M_FILEDESC, M_WAITOK | M_ZERO); 1411 FILEDESC_LOCK(fdp); 1412 mtx_init(&newfdp->fd_fd.fd_mtx, FILEDESC_LOCK_DESC, NULL, MTX_DEF); 1413 newfdp->fd_fd.fd_cdir = fdp->fd_cdir; 1414 if (newfdp->fd_fd.fd_cdir) 1415 VREF(newfdp->fd_fd.fd_cdir); 1416 newfdp->fd_fd.fd_rdir = fdp->fd_rdir; 1417 if (newfdp->fd_fd.fd_rdir) 1418 VREF(newfdp->fd_fd.fd_rdir); 1419 newfdp->fd_fd.fd_jdir = fdp->fd_jdir; 1420 if (newfdp->fd_fd.fd_jdir) 1421 VREF(newfdp->fd_fd.fd_jdir); 1422 1423 /* Create the file descriptor table. */ 1424 newfdp->fd_fd.fd_refcnt = 1; 1425 newfdp->fd_fd.fd_cmask = CMASK; 1426 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; 1427 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; 1428 newfdp->fd_fd.fd_nfiles = NDFILE; 1429 newfdp->fd_fd.fd_map = newfdp->fd_dmap; 1430 return (&newfdp->fd_fd); 1431 } 1432 1433 /* 1434 * Share a filedesc structure. 1435 */ 1436 struct filedesc * 1437 fdshare(fdp) 1438 struct filedesc *fdp; 1439 { 1440 FILEDESC_LOCK(fdp); 1441 fdp->fd_refcnt++; 1442 FILEDESC_UNLOCK(fdp); 1443 return (fdp); 1444 } 1445 1446 /* 1447 * Copy a filedesc structure. 1448 * A NULL pointer in returns a NULL reference, this is to ease callers, 1449 * not catch errors. 1450 */ 1451 struct filedesc * 1452 fdcopy(fdp) 1453 struct filedesc *fdp; 1454 { 1455 struct filedesc *newfdp; 1456 int i; 1457 1458 /* Certain daemons might not have file descriptors. */ 1459 if (fdp == NULL) 1460 return (NULL); 1461 1462 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1463 newfdp = fdinit(fdp); 1464 while (fdp->fd_lastfile >= newfdp->fd_nfiles) { 1465 FILEDESC_UNLOCK(fdp); 1466 FILEDESC_LOCK(newfdp); 1467 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1468 FILEDESC_UNLOCK(newfdp); 1469 FILEDESC_LOCK(fdp); 1470 } 1471 /* copy everything except kqueue descriptors */ 1472 newfdp->fd_freefile = -1; 1473 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1474 if (fdisused(fdp, i) && 1475 fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE) { 1476 newfdp->fd_ofiles[i] = fdp->fd_ofiles[i]; 1477 newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i]; 1478 fhold(newfdp->fd_ofiles[i]); 1479 newfdp->fd_lastfile = i; 1480 } else { 1481 if (newfdp->fd_freefile == -1) 1482 newfdp->fd_freefile = i; 1483 } 1484 } 1485 FILEDESC_UNLOCK(fdp); 1486 FILEDESC_LOCK(newfdp); 1487 for (i = 0; i <= newfdp->fd_lastfile; ++i) 1488 if (newfdp->fd_ofiles[i] != NULL) 1489 fdused(newfdp, i); 1490 FILEDESC_UNLOCK(newfdp); 1491 FILEDESC_LOCK(fdp); 1492 if (newfdp->fd_freefile == -1) 1493 newfdp->fd_freefile = i; 1494 newfdp->fd_cmask = fdp->fd_cmask; 1495 return (newfdp); 1496 } 1497 1498 /* A mutex to protect the association between a proc and filedesc. */ 1499 struct mtx fdesc_mtx; 1500 MTX_SYSINIT(fdesc, &fdesc_mtx, "fdesc", MTX_DEF); 1501 1502 /* 1503 * Release a filedesc structure. 1504 */ 1505 void 1506 fdfree(td) 1507 struct thread *td; 1508 { 1509 struct filedesc *fdp; 1510 struct file **fpp; 1511 int i; 1512 struct filedesc_to_leader *fdtol; 1513 struct file *fp; 1514 struct vnode *vp; 1515 struct flock lf; 1516 1517 GIANT_REQUIRED; /* VFS */ 1518 1519 /* Certain daemons might not have file descriptors. */ 1520 fdp = td->td_proc->p_fd; 1521 if (fdp == NULL) 1522 return; 1523 1524 /* Check for special need to clear POSIX style locks */ 1525 fdtol = td->td_proc->p_fdtol; 1526 if (fdtol != NULL) { 1527 FILEDESC_LOCK(fdp); 1528 KASSERT(fdtol->fdl_refcount > 0, 1529 ("filedesc_to_refcount botch: fdl_refcount=%d", 1530 fdtol->fdl_refcount)); 1531 if (fdtol->fdl_refcount == 1 && 1532 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1533 i = 0; 1534 fpp = fdp->fd_ofiles; 1535 for (i = 0, fpp = fdp->fd_ofiles; 1536 i <= fdp->fd_lastfile; 1537 i++, fpp++) { 1538 if (*fpp == NULL || 1539 (*fpp)->f_type != DTYPE_VNODE) 1540 continue; 1541 fp = *fpp; 1542 fhold(fp); 1543 FILEDESC_UNLOCK(fdp); 1544 lf.l_whence = SEEK_SET; 1545 lf.l_start = 0; 1546 lf.l_len = 0; 1547 lf.l_type = F_UNLCK; 1548 vp = fp->f_vnode; 1549 (void) VOP_ADVLOCK(vp, 1550 (caddr_t)td->td_proc-> 1551 p_leader, 1552 F_UNLCK, 1553 &lf, 1554 F_POSIX); 1555 FILEDESC_LOCK(fdp); 1556 fdrop(fp, td); 1557 fpp = fdp->fd_ofiles + i; 1558 } 1559 } 1560 retry: 1561 if (fdtol->fdl_refcount == 1) { 1562 if (fdp->fd_holdleaderscount > 0 && 1563 (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1564 /* 1565 * close() or do_dup() has cleared a reference 1566 * in a shared file descriptor table. 1567 */ 1568 fdp->fd_holdleaderswakeup = 1; 1569 msleep(&fdp->fd_holdleaderscount, &fdp->fd_mtx, 1570 PLOCK, "fdlhold", 0); 1571 goto retry; 1572 } 1573 if (fdtol->fdl_holdcount > 0) { 1574 /* 1575 * Ensure that fdtol->fdl_leader 1576 * remains valid in closef(). 1577 */ 1578 fdtol->fdl_wakeup = 1; 1579 msleep(fdtol, &fdp->fd_mtx, 1580 PLOCK, "fdlhold", 0); 1581 goto retry; 1582 } 1583 } 1584 fdtol->fdl_refcount--; 1585 if (fdtol->fdl_refcount == 0 && 1586 fdtol->fdl_holdcount == 0) { 1587 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 1588 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 1589 } else 1590 fdtol = NULL; 1591 td->td_proc->p_fdtol = NULL; 1592 FILEDESC_UNLOCK(fdp); 1593 if (fdtol != NULL) 1594 FREE(fdtol, M_FILEDESC_TO_LEADER); 1595 } 1596 FILEDESC_LOCK(fdp); 1597 if (--fdp->fd_refcnt > 0) { 1598 FILEDESC_UNLOCK(fdp); 1599 return; 1600 } 1601 1602 /* 1603 * We are the last reference to the structure, so we can 1604 * safely assume it will not change out from under us. 1605 */ 1606 FILEDESC_UNLOCK(fdp); 1607 fpp = fdp->fd_ofiles; 1608 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) { 1609 if (*fpp) 1610 (void) closef(*fpp, td); 1611 } 1612 1613 /* XXX This should happen earlier. */ 1614 mtx_lock(&fdesc_mtx); 1615 td->td_proc->p_fd = NULL; 1616 mtx_unlock(&fdesc_mtx); 1617 1618 if (fdp->fd_nfiles > NDFILE) 1619 FREE(fdp->fd_ofiles, M_FILEDESC); 1620 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE)) 1621 FREE(fdp->fd_map, M_FILEDESC); 1622 if (fdp->fd_cdir) 1623 vrele(fdp->fd_cdir); 1624 if (fdp->fd_rdir) 1625 vrele(fdp->fd_rdir); 1626 if (fdp->fd_jdir) 1627 vrele(fdp->fd_jdir); 1628 mtx_destroy(&fdp->fd_mtx); 1629 FREE(fdp, M_FILEDESC); 1630 } 1631 1632 /* 1633 * For setugid programs, we don't want to people to use that setugidness 1634 * to generate error messages which write to a file which otherwise would 1635 * otherwise be off-limits to the process. We check for filesystems where 1636 * the vnode can change out from under us after execve (like [lin]procfs). 1637 * 1638 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 1639 * sufficient. We also don't for check setugidness since we know we are. 1640 */ 1641 static int 1642 is_unsafe(struct file *fp) 1643 { 1644 if (fp->f_type == DTYPE_VNODE) { 1645 struct vnode *vp = fp->f_vnode; 1646 1647 if ((vp->v_vflag & VV_PROCDEP) != 0) 1648 return (1); 1649 } 1650 return (0); 1651 } 1652 1653 /* 1654 * Make this setguid thing safe, if at all possible. 1655 */ 1656 void 1657 setugidsafety(td) 1658 struct thread *td; 1659 { 1660 struct filedesc *fdp; 1661 int i; 1662 1663 GIANT_REQUIRED; /* kqueue */ 1664 1665 /* Certain daemons might not have file descriptors. */ 1666 fdp = td->td_proc->p_fd; 1667 if (fdp == NULL) 1668 return; 1669 1670 /* 1671 * Note: fdp->fd_ofiles may be reallocated out from under us while 1672 * we are blocked in a close. Be careful! 1673 */ 1674 FILEDESC_LOCK(fdp); 1675 for (i = 0; i <= fdp->fd_lastfile; i++) { 1676 if (i > 2) 1677 break; 1678 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) { 1679 struct file *fp; 1680 1681 knote_fdclose(td, i); 1682 /* 1683 * NULL-out descriptor prior to close to avoid 1684 * a race while close blocks. 1685 */ 1686 fp = fdp->fd_ofiles[i]; 1687 fdp->fd_ofiles[i] = NULL; 1688 fdp->fd_ofileflags[i] = 0; 1689 fdunused(fdp, i); 1690 FILEDESC_UNLOCK(fdp); 1691 (void) closef(fp, td); 1692 FILEDESC_LOCK(fdp); 1693 } 1694 } 1695 FILEDESC_UNLOCK(fdp); 1696 } 1697 1698 /* 1699 * Close any files on exec? 1700 */ 1701 void 1702 fdcloseexec(td) 1703 struct thread *td; 1704 { 1705 struct filedesc *fdp; 1706 int i; 1707 1708 /* Certain daemons might not have file descriptors. */ 1709 fdp = td->td_proc->p_fd; 1710 if (fdp == NULL) 1711 return; 1712 1713 FILEDESC_LOCK(fdp); 1714 1715 /* 1716 * We cannot cache fd_ofiles or fd_ofileflags since operations 1717 * may block and rip them out from under us. 1718 */ 1719 for (i = 0; i <= fdp->fd_lastfile; i++) { 1720 if (fdp->fd_ofiles[i] != NULL && 1721 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) { 1722 struct file *fp; 1723 1724 knote_fdclose(td, i); 1725 /* 1726 * NULL-out descriptor prior to close to avoid 1727 * a race while close blocks. 1728 */ 1729 fp = fdp->fd_ofiles[i]; 1730 fdp->fd_ofiles[i] = NULL; 1731 fdp->fd_ofileflags[i] = 0; 1732 fdunused(fdp, i); 1733 FILEDESC_UNLOCK(fdp); 1734 (void) closef(fp, td); 1735 FILEDESC_LOCK(fdp); 1736 } 1737 } 1738 FILEDESC_UNLOCK(fdp); 1739 } 1740 1741 /* 1742 * It is unsafe for set[ug]id processes to be started with file 1743 * descriptors 0..2 closed, as these descriptors are given implicit 1744 * significance in the Standard C library. fdcheckstd() will create a 1745 * descriptor referencing /dev/null for each of stdin, stdout, and 1746 * stderr that is not already open. 1747 */ 1748 int 1749 fdcheckstd(td) 1750 struct thread *td; 1751 { 1752 struct nameidata nd; 1753 struct filedesc *fdp; 1754 struct file *fp; 1755 register_t retval; 1756 int fd, i, error, flags, devnull; 1757 1758 GIANT_REQUIRED; /* VFS */ 1759 1760 fdp = td->td_proc->p_fd; 1761 if (fdp == NULL) 1762 return (0); 1763 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 1764 devnull = -1; 1765 error = 0; 1766 for (i = 0; i < 3; i++) { 1767 if (fdp->fd_ofiles[i] != NULL) 1768 continue; 1769 if (devnull < 0) { 1770 error = falloc(td, &fp, &fd); 1771 if (error != 0) 1772 break; 1773 /* Note extra ref on `fp' held for us by falloc(). */ 1774 KASSERT(fd == i, ("oof, we didn't get our fd")); 1775 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/null", 1776 td); 1777 flags = FREAD | FWRITE; 1778 error = vn_open(&nd, &flags, 0, -1); 1779 if (error != 0) { 1780 /* 1781 * Someone may have closed the entry in the 1782 * file descriptor table, so check it hasn't 1783 * changed before dropping the reference count. 1784 */ 1785 FILEDESC_LOCK(fdp); 1786 KASSERT(fdp->fd_ofiles[fd] == fp, 1787 ("table not shared, how did it change?")); 1788 fdp->fd_ofiles[fd] = NULL; 1789 fdunused(fdp, fd); 1790 FILEDESC_UNLOCK(fdp); 1791 fdrop(fp, td); 1792 fdrop(fp, td); 1793 break; 1794 } 1795 NDFREE(&nd, NDF_ONLY_PNBUF); 1796 fp->f_vnode = nd.ni_vp; 1797 fp->f_data = nd.ni_vp; 1798 fp->f_flag = flags; 1799 fp->f_ops = &vnops; 1800 fp->f_type = DTYPE_VNODE; 1801 VOP_UNLOCK(nd.ni_vp, 0, td); 1802 devnull = fd; 1803 fdrop(fp, td); 1804 } else { 1805 error = do_dup(td, DUP_FIXED, devnull, i, &retval); 1806 if (error != 0) 1807 break; 1808 } 1809 } 1810 return (error); 1811 } 1812 1813 /* 1814 * Internal form of close. 1815 * Decrement reference count on file structure. 1816 * Note: td may be NULL when closing a file 1817 * that was being passed in a message. 1818 */ 1819 int 1820 closef(fp, td) 1821 struct file *fp; 1822 struct thread *td; 1823 { 1824 struct vnode *vp; 1825 struct flock lf; 1826 struct filedesc_to_leader *fdtol; 1827 struct filedesc *fdp; 1828 1829 if (fp == NULL) 1830 return (0); 1831 /* 1832 * POSIX record locking dictates that any close releases ALL 1833 * locks owned by this process. This is handled by setting 1834 * a flag in the unlock to free ONLY locks obeying POSIX 1835 * semantics, and not to free BSD-style file locks. 1836 * If the descriptor was in a message, POSIX-style locks 1837 * aren't passed with the descriptor. 1838 */ 1839 if (td != NULL && 1840 fp->f_type == DTYPE_VNODE) { 1841 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 1842 lf.l_whence = SEEK_SET; 1843 lf.l_start = 0; 1844 lf.l_len = 0; 1845 lf.l_type = F_UNLCK; 1846 vp = fp->f_vnode; 1847 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader, 1848 F_UNLCK, &lf, F_POSIX); 1849 } 1850 fdtol = td->td_proc->p_fdtol; 1851 if (fdtol != NULL) { 1852 /* 1853 * Handle special case where file descriptor table 1854 * is shared between multiple process leaders. 1855 */ 1856 fdp = td->td_proc->p_fd; 1857 FILEDESC_LOCK(fdp); 1858 for (fdtol = fdtol->fdl_next; 1859 fdtol != td->td_proc->p_fdtol; 1860 fdtol = fdtol->fdl_next) { 1861 if ((fdtol->fdl_leader->p_flag & 1862 P_ADVLOCK) == 0) 1863 continue; 1864 fdtol->fdl_holdcount++; 1865 FILEDESC_UNLOCK(fdp); 1866 lf.l_whence = SEEK_SET; 1867 lf.l_start = 0; 1868 lf.l_len = 0; 1869 lf.l_type = F_UNLCK; 1870 vp = fp->f_vnode; 1871 (void) VOP_ADVLOCK(vp, 1872 (caddr_t)fdtol->fdl_leader, 1873 F_UNLCK, &lf, F_POSIX); 1874 FILEDESC_LOCK(fdp); 1875 fdtol->fdl_holdcount--; 1876 if (fdtol->fdl_holdcount == 0 && 1877 fdtol->fdl_wakeup != 0) { 1878 fdtol->fdl_wakeup = 0; 1879 wakeup(fdtol); 1880 } 1881 } 1882 FILEDESC_UNLOCK(fdp); 1883 } 1884 } 1885 return (fdrop(fp, td)); 1886 } 1887 1888 /* 1889 * Drop reference on struct file passed in, may call closef if the 1890 * reference hits zero. 1891 */ 1892 int 1893 fdrop(fp, td) 1894 struct file *fp; 1895 struct thread *td; 1896 { 1897 1898 FILE_LOCK(fp); 1899 return (fdrop_locked(fp, td)); 1900 } 1901 1902 /* 1903 * Extract the file pointer associated with the specified descriptor for 1904 * the current user process. 1905 * 1906 * If the descriptor doesn't exist, EBADF is returned. 1907 * 1908 * If the descriptor exists but doesn't match 'flags' then 1909 * return EBADF for read attempts and EINVAL for write attempts. 1910 * 1911 * If 'hold' is set (non-zero) the file's refcount will be bumped on return. 1912 * It should be droped with fdrop(). 1913 * If it is not set, then the refcount will not be bumped however the 1914 * thread's filedesc struct will be returned locked (for fgetsock). 1915 * 1916 * If an error occured the non-zero error is returned and *fpp is set to NULL. 1917 * Otherwise *fpp is set and zero is returned. 1918 */ 1919 static __inline int 1920 _fget(struct thread *td, int fd, struct file **fpp, int flags, int hold) 1921 { 1922 struct filedesc *fdp; 1923 struct file *fp; 1924 1925 *fpp = NULL; 1926 if (td == NULL || (fdp = td->td_proc->p_fd) == NULL) 1927 return (EBADF); 1928 FILEDESC_LOCK(fdp); 1929 if ((fp = fget_locked(fdp, fd)) == NULL || fp->f_ops == &badfileops) { 1930 FILEDESC_UNLOCK(fdp); 1931 return (EBADF); 1932 } 1933 1934 /* 1935 * Note: FREAD failures returns EBADF to maintain backwards 1936 * compatibility with what routines returned before. 1937 * 1938 * Only one flag, or 0, may be specified. 1939 */ 1940 if (flags == FREAD && (fp->f_flag & FREAD) == 0) { 1941 FILEDESC_UNLOCK(fdp); 1942 return (EBADF); 1943 } 1944 if (flags == FWRITE && (fp->f_flag & FWRITE) == 0) { 1945 FILEDESC_UNLOCK(fdp); 1946 return (EINVAL); 1947 } 1948 if (hold) { 1949 fhold(fp); 1950 FILEDESC_UNLOCK(fdp); 1951 } 1952 *fpp = fp; 1953 return (0); 1954 } 1955 1956 int 1957 fget(struct thread *td, int fd, struct file **fpp) 1958 { 1959 1960 return(_fget(td, fd, fpp, 0, 1)); 1961 } 1962 1963 int 1964 fget_read(struct thread *td, int fd, struct file **fpp) 1965 { 1966 1967 return(_fget(td, fd, fpp, FREAD, 1)); 1968 } 1969 1970 int 1971 fget_write(struct thread *td, int fd, struct file **fpp) 1972 { 1973 1974 return(_fget(td, fd, fpp, FWRITE, 1)); 1975 } 1976 1977 /* 1978 * Like fget() but loads the underlying vnode, or returns an error if 1979 * the descriptor does not represent a vnode. Note that pipes use vnodes 1980 * but never have VM objects (so VOP_GETVOBJECT() calls will return an 1981 * error). The returned vnode will be vref()d. 1982 */ 1983 static __inline int 1984 _fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags) 1985 { 1986 struct file *fp; 1987 int error; 1988 1989 GIANT_REQUIRED; /* VFS */ 1990 1991 *vpp = NULL; 1992 if ((error = _fget(td, fd, &fp, 0, 0)) != 0) 1993 return (error); 1994 if (fp->f_vnode == NULL) { 1995 error = EINVAL; 1996 } else { 1997 *vpp = fp->f_vnode; 1998 vref(*vpp); 1999 } 2000 FILEDESC_UNLOCK(td->td_proc->p_fd); 2001 return (error); 2002 } 2003 2004 int 2005 fgetvp(struct thread *td, int fd, struct vnode **vpp) 2006 { 2007 2008 return (_fgetvp(td, fd, vpp, 0)); 2009 } 2010 2011 int 2012 fgetvp_read(struct thread *td, int fd, struct vnode **vpp) 2013 { 2014 2015 return (_fgetvp(td, fd, vpp, FREAD)); 2016 } 2017 2018 int 2019 fgetvp_write(struct thread *td, int fd, struct vnode **vpp) 2020 { 2021 2022 return (_fgetvp(td, fd, vpp, FWRITE)); 2023 } 2024 2025 /* 2026 * Like fget() but loads the underlying socket, or returns an error if 2027 * the descriptor does not represent a socket. 2028 * 2029 * We bump the ref count on the returned socket. XXX Also obtain the SX 2030 * lock in the future. 2031 */ 2032 int 2033 fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp) 2034 { 2035 struct file *fp; 2036 int error; 2037 2038 NET_ASSERT_GIANT(); 2039 2040 *spp = NULL; 2041 if (fflagp != NULL) 2042 *fflagp = 0; 2043 if ((error = _fget(td, fd, &fp, 0, 0)) != 0) 2044 return (error); 2045 if (fp->f_type != DTYPE_SOCKET) { 2046 error = ENOTSOCK; 2047 } else { 2048 *spp = fp->f_data; 2049 if (fflagp) 2050 *fflagp = fp->f_flag; 2051 SOCK_LOCK(*spp); 2052 soref(*spp); 2053 SOCK_UNLOCK(*spp); 2054 } 2055 FILEDESC_UNLOCK(td->td_proc->p_fd); 2056 return (error); 2057 } 2058 2059 /* 2060 * Drop the reference count on the the socket and XXX release the SX lock in 2061 * the future. The last reference closes the socket. 2062 */ 2063 void 2064 fputsock(struct socket *so) 2065 { 2066 2067 NET_ASSERT_GIANT(); 2068 SOCK_LOCK(so); 2069 sorele(so); 2070 } 2071 2072 /* 2073 * Drop reference on struct file passed in, may call closef if the 2074 * reference hits zero. 2075 * Expects struct file locked, and will unlock it. 2076 */ 2077 int 2078 fdrop_locked(fp, td) 2079 struct file *fp; 2080 struct thread *td; 2081 { 2082 int error; 2083 2084 FILE_LOCK_ASSERT(fp, MA_OWNED); 2085 2086 if (--fp->f_count > 0) { 2087 FILE_UNLOCK(fp); 2088 return (0); 2089 } 2090 /* We have the last ref so we can proceed without the file lock. */ 2091 FILE_UNLOCK(fp); 2092 if (fp->f_count < 0) 2093 panic("fdrop: count < 0"); 2094 if (fp->f_ops != &badfileops) 2095 error = fo_close(fp, td); 2096 else 2097 error = 0; 2098 ffree(fp); 2099 return (error); 2100 } 2101 2102 /* 2103 * Apply an advisory lock on a file descriptor. 2104 * 2105 * Just attempt to get a record lock of the requested type on 2106 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2107 */ 2108 #ifndef _SYS_SYSPROTO_H_ 2109 struct flock_args { 2110 int fd; 2111 int how; 2112 }; 2113 #endif 2114 /* 2115 * MPSAFE 2116 */ 2117 /* ARGSUSED */ 2118 int 2119 flock(td, uap) 2120 struct thread *td; 2121 struct flock_args *uap; 2122 { 2123 struct file *fp; 2124 struct vnode *vp; 2125 struct flock lf; 2126 int error; 2127 2128 if ((error = fget(td, uap->fd, &fp)) != 0) 2129 return (error); 2130 if (fp->f_type != DTYPE_VNODE) { 2131 fdrop(fp, td); 2132 return (EOPNOTSUPP); 2133 } 2134 2135 mtx_lock(&Giant); 2136 vp = fp->f_vnode; 2137 lf.l_whence = SEEK_SET; 2138 lf.l_start = 0; 2139 lf.l_len = 0; 2140 if (uap->how & LOCK_UN) { 2141 lf.l_type = F_UNLCK; 2142 FILE_LOCK(fp); 2143 fp->f_flag &= ~FHASLOCK; 2144 FILE_UNLOCK(fp); 2145 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 2146 goto done2; 2147 } 2148 if (uap->how & LOCK_EX) 2149 lf.l_type = F_WRLCK; 2150 else if (uap->how & LOCK_SH) 2151 lf.l_type = F_RDLCK; 2152 else { 2153 error = EBADF; 2154 goto done2; 2155 } 2156 FILE_LOCK(fp); 2157 fp->f_flag |= FHASLOCK; 2158 FILE_UNLOCK(fp); 2159 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 2160 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT); 2161 done2: 2162 fdrop(fp, td); 2163 mtx_unlock(&Giant); 2164 return (error); 2165 } 2166 2167 /* 2168 * File Descriptor pseudo-device driver (/dev/fd/). 2169 * 2170 * Opening minor device N dup()s the file (if any) connected to file 2171 * descriptor N belonging to the calling process. Note that this driver 2172 * consists of only the ``open()'' routine, because all subsequent 2173 * references to this file will be direct to the other driver. 2174 */ 2175 /* ARGSUSED */ 2176 static int 2177 fdopen(dev, mode, type, td) 2178 struct cdev *dev; 2179 int mode, type; 2180 struct thread *td; 2181 { 2182 2183 /* 2184 * XXX Kludge: set curthread->td_dupfd to contain the value of the 2185 * the file descriptor being sought for duplication. The error 2186 * return ensures that the vnode for this device will be released 2187 * by vn_open. Open will detect this special error and take the 2188 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 2189 * will simply report the error. 2190 */ 2191 td->td_dupfd = dev2unit(dev); 2192 return (ENODEV); 2193 } 2194 2195 /* 2196 * Duplicate the specified descriptor to a free descriptor. 2197 */ 2198 int 2199 dupfdopen(td, fdp, indx, dfd, mode, error) 2200 struct thread *td; 2201 struct filedesc *fdp; 2202 int indx, dfd; 2203 int mode; 2204 int error; 2205 { 2206 struct file *wfp; 2207 struct file *fp; 2208 2209 /* 2210 * If the to-be-dup'd fd number is greater than the allowed number 2211 * of file descriptors, or the fd to be dup'd has already been 2212 * closed, then reject. 2213 */ 2214 FILEDESC_LOCK(fdp); 2215 if (dfd < 0 || dfd >= fdp->fd_nfiles || 2216 (wfp = fdp->fd_ofiles[dfd]) == NULL) { 2217 FILEDESC_UNLOCK(fdp); 2218 return (EBADF); 2219 } 2220 2221 /* 2222 * There are two cases of interest here. 2223 * 2224 * For ENODEV simply dup (dfd) to file descriptor 2225 * (indx) and return. 2226 * 2227 * For ENXIO steal away the file structure from (dfd) and 2228 * store it in (indx). (dfd) is effectively closed by 2229 * this operation. 2230 * 2231 * Any other error code is just returned. 2232 */ 2233 switch (error) { 2234 case ENODEV: 2235 /* 2236 * Check that the mode the file is being opened for is a 2237 * subset of the mode of the existing descriptor. 2238 */ 2239 FILE_LOCK(wfp); 2240 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 2241 FILE_UNLOCK(wfp); 2242 FILEDESC_UNLOCK(fdp); 2243 return (EACCES); 2244 } 2245 fp = fdp->fd_ofiles[indx]; 2246 fdp->fd_ofiles[indx] = wfp; 2247 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2248 if (fp == NULL) 2249 fdused(fdp, indx); 2250 fhold_locked(wfp); 2251 FILE_UNLOCK(wfp); 2252 if (fp != NULL) 2253 FILE_LOCK(fp); 2254 FILEDESC_UNLOCK(fdp); 2255 /* 2256 * We now own the reference to fp that the ofiles[] array 2257 * used to own. Release it. 2258 */ 2259 if (fp != NULL) 2260 fdrop_locked(fp, td); 2261 return (0); 2262 2263 case ENXIO: 2264 /* 2265 * Steal away the file pointer from dfd and stuff it into indx. 2266 */ 2267 fp = fdp->fd_ofiles[indx]; 2268 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd]; 2269 fdp->fd_ofiles[dfd] = NULL; 2270 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd]; 2271 fdp->fd_ofileflags[dfd] = 0; 2272 fdunused(fdp, dfd); 2273 if (fp == NULL) 2274 fdused(fdp, indx); 2275 if (fp != NULL) 2276 FILE_LOCK(fp); 2277 FILEDESC_UNLOCK(fdp); 2278 2279 /* 2280 * we now own the reference to fp that the ofiles[] array 2281 * used to own. Release it. 2282 */ 2283 if (fp != NULL) 2284 fdrop_locked(fp, td); 2285 return (0); 2286 2287 default: 2288 FILEDESC_UNLOCK(fdp); 2289 return (error); 2290 } 2291 /* NOTREACHED */ 2292 } 2293 2294 struct filedesc_to_leader * 2295 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 2296 struct filedesc *fdp, 2297 struct proc *leader) 2298 { 2299 struct filedesc_to_leader *fdtol; 2300 2301 MALLOC(fdtol, struct filedesc_to_leader *, 2302 sizeof(struct filedesc_to_leader), 2303 M_FILEDESC_TO_LEADER, 2304 M_WAITOK); 2305 fdtol->fdl_refcount = 1; 2306 fdtol->fdl_holdcount = 0; 2307 fdtol->fdl_wakeup = 0; 2308 fdtol->fdl_leader = leader; 2309 if (old != NULL) { 2310 FILEDESC_LOCK(fdp); 2311 fdtol->fdl_next = old->fdl_next; 2312 fdtol->fdl_prev = old; 2313 old->fdl_next = fdtol; 2314 fdtol->fdl_next->fdl_prev = fdtol; 2315 FILEDESC_UNLOCK(fdp); 2316 } else { 2317 fdtol->fdl_next = fdtol; 2318 fdtol->fdl_prev = fdtol; 2319 } 2320 return (fdtol); 2321 } 2322 2323 /* 2324 * Get file structures. 2325 */ 2326 static int 2327 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 2328 { 2329 struct xfile xf; 2330 struct filedesc *fdp; 2331 struct file *fp; 2332 struct proc *p; 2333 int error, n; 2334 2335 /* 2336 * Note: because the number of file descriptors is calculated 2337 * in different ways for sizing vs returning the data, 2338 * there is information leakage from the first loop. However, 2339 * it is of a similar order of magnitude to the leakage from 2340 * global system statistics such as kern.openfiles. 2341 */ 2342 error = sysctl_wire_old_buffer(req, 0); 2343 if (error != 0) 2344 return (error); 2345 if (req->oldptr == NULL) { 2346 n = 16; /* A slight overestimate. */ 2347 sx_slock(&filelist_lock); 2348 LIST_FOREACH(fp, &filehead, f_list) { 2349 /* 2350 * We should grab the lock, but this is an 2351 * estimate, so does it really matter? 2352 */ 2353 /* mtx_lock(fp->f_mtxp); */ 2354 n += fp->f_count; 2355 /* mtx_unlock(f->f_mtxp); */ 2356 } 2357 sx_sunlock(&filelist_lock); 2358 return (SYSCTL_OUT(req, 0, n * sizeof(xf))); 2359 } 2360 error = 0; 2361 bzero(&xf, sizeof(xf)); 2362 xf.xf_size = sizeof(xf); 2363 sx_slock(&allproc_lock); 2364 LIST_FOREACH(p, &allproc, p_list) { 2365 PROC_LOCK(p); 2366 if (p_cansee(req->td, p) != 0) { 2367 PROC_UNLOCK(p); 2368 continue; 2369 } 2370 xf.xf_pid = p->p_pid; 2371 xf.xf_uid = p->p_ucred->cr_uid; 2372 PROC_UNLOCK(p); 2373 mtx_lock(&fdesc_mtx); 2374 if ((fdp = p->p_fd) == NULL) { 2375 mtx_unlock(&fdesc_mtx); 2376 continue; 2377 } 2378 FILEDESC_LOCK(fdp); 2379 for (n = 0; n < fdp->fd_nfiles; ++n) { 2380 if ((fp = fdp->fd_ofiles[n]) == NULL) 2381 continue; 2382 xf.xf_fd = n; 2383 xf.xf_file = fp; 2384 xf.xf_data = fp->f_data; 2385 xf.xf_vnode = fp->f_vnode; 2386 xf.xf_type = fp->f_type; 2387 xf.xf_count = fp->f_count; 2388 xf.xf_msgcount = fp->f_msgcount; 2389 xf.xf_offset = fp->f_offset; 2390 xf.xf_flag = fp->f_flag; 2391 error = SYSCTL_OUT(req, &xf, sizeof(xf)); 2392 if (error) 2393 break; 2394 } 2395 FILEDESC_UNLOCK(fdp); 2396 mtx_unlock(&fdesc_mtx); 2397 if (error) 2398 break; 2399 } 2400 sx_sunlock(&allproc_lock); 2401 return (error); 2402 } 2403 2404 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 2405 0, 0, sysctl_kern_file, "S,xfile", "Entire file table"); 2406 2407 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 2408 &maxfilesperproc, 0, "Maximum files allowed open per process"); 2409 2410 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 2411 &maxfiles, 0, "Maximum number of files"); 2412 2413 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 2414 &nfiles, 0, "System-wide number of open files"); 2415 2416 static void 2417 fildesc_drvinit(void *unused) 2418 { 2419 struct cdev *dev; 2420 2421 dev = make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "fd/0"); 2422 make_dev_alias(dev, "stdin"); 2423 dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1"); 2424 make_dev_alias(dev, "stdout"); 2425 dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2"); 2426 make_dev_alias(dev, "stderr"); 2427 } 2428 2429 static fo_rdwr_t badfo_readwrite; 2430 static fo_ioctl_t badfo_ioctl; 2431 static fo_poll_t badfo_poll; 2432 static fo_kqfilter_t badfo_kqfilter; 2433 static fo_stat_t badfo_stat; 2434 static fo_close_t badfo_close; 2435 2436 struct fileops badfileops = { 2437 .fo_read = badfo_readwrite, 2438 .fo_write = badfo_readwrite, 2439 .fo_ioctl = badfo_ioctl, 2440 .fo_poll = badfo_poll, 2441 .fo_kqfilter = badfo_kqfilter, 2442 .fo_stat = badfo_stat, 2443 .fo_close = badfo_close, 2444 }; 2445 2446 static int 2447 badfo_readwrite(fp, uio, active_cred, flags, td) 2448 struct file *fp; 2449 struct uio *uio; 2450 struct ucred *active_cred; 2451 struct thread *td; 2452 int flags; 2453 { 2454 2455 return (EBADF); 2456 } 2457 2458 static int 2459 badfo_ioctl(fp, com, data, active_cred, td) 2460 struct file *fp; 2461 u_long com; 2462 void *data; 2463 struct ucred *active_cred; 2464 struct thread *td; 2465 { 2466 2467 return (EBADF); 2468 } 2469 2470 static int 2471 badfo_poll(fp, events, active_cred, td) 2472 struct file *fp; 2473 int events; 2474 struct ucred *active_cred; 2475 struct thread *td; 2476 { 2477 2478 return (0); 2479 } 2480 2481 static int 2482 badfo_kqfilter(fp, kn) 2483 struct file *fp; 2484 struct knote *kn; 2485 { 2486 2487 return (0); 2488 } 2489 2490 static int 2491 badfo_stat(fp, sb, active_cred, td) 2492 struct file *fp; 2493 struct stat *sb; 2494 struct ucred *active_cred; 2495 struct thread *td; 2496 { 2497 2498 return (EBADF); 2499 } 2500 2501 static int 2502 badfo_close(fp, td) 2503 struct file *fp; 2504 struct thread *td; 2505 { 2506 2507 return (EBADF); 2508 } 2509 2510 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, 2511 fildesc_drvinit,NULL) 2512 2513 static void filelistinit(void *); 2514 SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL) 2515 2516 /* ARGSUSED*/ 2517 static void 2518 filelistinit(dummy) 2519 void *dummy; 2520 { 2521 2522 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL, 2523 NULL, NULL, UMA_ALIGN_PTR, 0); 2524 sx_init(&filelist_lock, "filelist lock"); 2525 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF); 2526 } 2527