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 * 3. 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_capsicum.h" 41 #include "opt_compat.h" 42 #include "opt_ddb.h" 43 #include "opt_ktrace.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 48 #include <sys/capsicum.h> 49 #include <sys/conf.h> 50 #include <sys/fcntl.h> 51 #include <sys/file.h> 52 #include <sys/filedesc.h> 53 #include <sys/filio.h> 54 #include <sys/jail.h> 55 #include <sys/kernel.h> 56 #include <sys/limits.h> 57 #include <sys/lock.h> 58 #include <sys/malloc.h> 59 #include <sys/mount.h> 60 #include <sys/mutex.h> 61 #include <sys/namei.h> 62 #include <sys/selinfo.h> 63 #include <sys/priv.h> 64 #include <sys/proc.h> 65 #include <sys/protosw.h> 66 #include <sys/racct.h> 67 #include <sys/resourcevar.h> 68 #include <sys/sbuf.h> 69 #include <sys/signalvar.h> 70 #include <sys/kdb.h> 71 #include <sys/stat.h> 72 #include <sys/sx.h> 73 #include <sys/syscallsubr.h> 74 #include <sys/sysctl.h> 75 #include <sys/sysproto.h> 76 #include <sys/unistd.h> 77 #include <sys/user.h> 78 #include <sys/vnode.h> 79 #ifdef KTRACE 80 #include <sys/ktrace.h> 81 #endif 82 83 #include <net/vnet.h> 84 85 #include <security/audit/audit.h> 86 87 #include <vm/uma.h> 88 #include <vm/vm.h> 89 90 #include <ddb/ddb.h> 91 92 static MALLOC_DEFINE(M_FILEDESC, "filedesc", "Open file descriptor table"); 93 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "filedesc_to_leader", 94 "file desc to leader structures"); 95 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 96 MALLOC_DEFINE(M_FILECAPS, "filecaps", "descriptor capabilities"); 97 98 MALLOC_DECLARE(M_FADVISE); 99 100 static __read_mostly uma_zone_t file_zone; 101 static __read_mostly uma_zone_t filedesc0_zone; 102 103 static int closefp(struct filedesc *fdp, int fd, struct file *fp, 104 struct thread *td, int holdleaders); 105 static int fd_first_free(struct filedesc *fdp, int low, int size); 106 static int fd_last_used(struct filedesc *fdp, int size); 107 static void fdgrowtable(struct filedesc *fdp, int nfd); 108 static void fdgrowtable_exp(struct filedesc *fdp, int nfd); 109 static void fdunused(struct filedesc *fdp, int fd); 110 static void fdused(struct filedesc *fdp, int fd); 111 static int getmaxfd(struct thread *td); 112 113 /* 114 * Each process has: 115 * 116 * - An array of open file descriptors (fd_ofiles) 117 * - An array of file flags (fd_ofileflags) 118 * - A bitmap recording which descriptors are in use (fd_map) 119 * 120 * A process starts out with NDFILE descriptors. The value of NDFILE has 121 * been selected based the historical limit of 20 open files, and an 122 * assumption that the majority of processes, especially short-lived 123 * processes like shells, will never need more. 124 * 125 * If this initial allocation is exhausted, a larger descriptor table and 126 * map are allocated dynamically, and the pointers in the process's struct 127 * filedesc are updated to point to those. This is repeated every time 128 * the process runs out of file descriptors (provided it hasn't hit its 129 * resource limit). 130 * 131 * Since threads may hold references to individual descriptor table 132 * entries, the tables are never freed. Instead, they are placed on a 133 * linked list and freed only when the struct filedesc is released. 134 */ 135 #define NDFILE 20 136 #define NDSLOTSIZE sizeof(NDSLOTTYPE) 137 #define NDENTRIES (NDSLOTSIZE * __CHAR_BIT) 138 #define NDSLOT(x) ((x) / NDENTRIES) 139 #define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES)) 140 #define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES) 141 142 /* 143 * SLIST entry used to keep track of ofiles which must be reclaimed when 144 * the process exits. 145 */ 146 struct freetable { 147 struct fdescenttbl *ft_table; 148 SLIST_ENTRY(freetable) ft_next; 149 }; 150 151 /* 152 * Initial allocation: a filedesc structure + the head of SLIST used to 153 * keep track of old ofiles + enough space for NDFILE descriptors. 154 */ 155 156 struct fdescenttbl0 { 157 int fdt_nfiles; 158 struct filedescent fdt_ofiles[NDFILE]; 159 }; 160 161 struct filedesc0 { 162 struct filedesc fd_fd; 163 SLIST_HEAD(, freetable) fd_free; 164 struct fdescenttbl0 fd_dfiles; 165 NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)]; 166 }; 167 168 /* 169 * Descriptor management. 170 */ 171 volatile int __exclusive_cache_line openfiles; /* actual number of open files */ 172 struct mtx sigio_lock; /* mtx to protect pointers to sigio */ 173 void __read_mostly (*mq_fdclose)(struct thread *td, int fd, struct file *fp); 174 175 /* 176 * If low >= size, just return low. Otherwise find the first zero bit in the 177 * given bitmap, starting at low and not exceeding size - 1. Return size if 178 * not found. 179 */ 180 static int 181 fd_first_free(struct filedesc *fdp, int low, int size) 182 { 183 NDSLOTTYPE *map = fdp->fd_map; 184 NDSLOTTYPE mask; 185 int off, maxoff; 186 187 if (low >= size) 188 return (low); 189 190 off = NDSLOT(low); 191 if (low % NDENTRIES) { 192 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES))); 193 if ((mask &= ~map[off]) != 0UL) 194 return (off * NDENTRIES + ffsl(mask) - 1); 195 ++off; 196 } 197 for (maxoff = NDSLOTS(size); off < maxoff; ++off) 198 if (map[off] != ~0UL) 199 return (off * NDENTRIES + ffsl(~map[off]) - 1); 200 return (size); 201 } 202 203 /* 204 * Find the highest non-zero bit in the given bitmap, starting at 0 and 205 * not exceeding size - 1. Return -1 if not found. 206 */ 207 static int 208 fd_last_used(struct filedesc *fdp, int size) 209 { 210 NDSLOTTYPE *map = fdp->fd_map; 211 NDSLOTTYPE mask; 212 int off, minoff; 213 214 off = NDSLOT(size); 215 if (size % NDENTRIES) { 216 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES)); 217 if ((mask &= map[off]) != 0) 218 return (off * NDENTRIES + flsl(mask) - 1); 219 --off; 220 } 221 for (minoff = NDSLOT(0); off >= minoff; --off) 222 if (map[off] != 0) 223 return (off * NDENTRIES + flsl(map[off]) - 1); 224 return (-1); 225 } 226 227 static int 228 fdisused(struct filedesc *fdp, int fd) 229 { 230 231 KASSERT(fd >= 0 && fd < fdp->fd_nfiles, 232 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles)); 233 234 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0); 235 } 236 237 /* 238 * Mark a file descriptor as used. 239 */ 240 static void 241 fdused_init(struct filedesc *fdp, int fd) 242 { 243 244 KASSERT(!fdisused(fdp, fd), ("fd=%d is already used", fd)); 245 246 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd); 247 } 248 249 static void 250 fdused(struct filedesc *fdp, int fd) 251 { 252 253 FILEDESC_XLOCK_ASSERT(fdp); 254 255 fdused_init(fdp, fd); 256 if (fd > fdp->fd_lastfile) 257 fdp->fd_lastfile = fd; 258 if (fd == fdp->fd_freefile) 259 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 260 } 261 262 /* 263 * Mark a file descriptor as unused. 264 */ 265 static void 266 fdunused(struct filedesc *fdp, int fd) 267 { 268 269 FILEDESC_XLOCK_ASSERT(fdp); 270 271 KASSERT(fdisused(fdp, fd), ("fd=%d is already unused", fd)); 272 KASSERT(fdp->fd_ofiles[fd].fde_file == NULL, 273 ("fd=%d is still in use", fd)); 274 275 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd); 276 if (fd < fdp->fd_freefile) 277 fdp->fd_freefile = fd; 278 if (fd == fdp->fd_lastfile) 279 fdp->fd_lastfile = fd_last_used(fdp, fd); 280 } 281 282 /* 283 * Free a file descriptor. 284 * 285 * Avoid some work if fdp is about to be destroyed. 286 */ 287 static inline void 288 fdefree_last(struct filedescent *fde) 289 { 290 291 filecaps_free(&fde->fde_caps); 292 } 293 294 static inline void 295 fdfree(struct filedesc *fdp, int fd) 296 { 297 struct filedescent *fde; 298 299 fde = &fdp->fd_ofiles[fd]; 300 #ifdef CAPABILITIES 301 seq_write_begin(&fde->fde_seq); 302 #endif 303 fdefree_last(fde); 304 fde->fde_file = NULL; 305 fdunused(fdp, fd); 306 #ifdef CAPABILITIES 307 seq_write_end(&fde->fde_seq); 308 #endif 309 } 310 311 void 312 pwd_ensure_dirs(void) 313 { 314 struct filedesc *fdp; 315 316 fdp = curproc->p_fd; 317 FILEDESC_XLOCK(fdp); 318 if (fdp->fd_cdir == NULL) { 319 fdp->fd_cdir = rootvnode; 320 vrefact(rootvnode); 321 } 322 if (fdp->fd_rdir == NULL) { 323 fdp->fd_rdir = rootvnode; 324 vrefact(rootvnode); 325 } 326 FILEDESC_XUNLOCK(fdp); 327 } 328 329 /* 330 * System calls on descriptors. 331 */ 332 #ifndef _SYS_SYSPROTO_H_ 333 struct getdtablesize_args { 334 int dummy; 335 }; 336 #endif 337 /* ARGSUSED */ 338 int 339 sys_getdtablesize(struct thread *td, struct getdtablesize_args *uap) 340 { 341 #ifdef RACCT 342 uint64_t lim; 343 #endif 344 345 td->td_retval[0] = 346 min((int)lim_cur(td, RLIMIT_NOFILE), maxfilesperproc); 347 #ifdef RACCT 348 PROC_LOCK(td->td_proc); 349 lim = racct_get_limit(td->td_proc, RACCT_NOFILE); 350 PROC_UNLOCK(td->td_proc); 351 if (lim < td->td_retval[0]) 352 td->td_retval[0] = lim; 353 #endif 354 return (0); 355 } 356 357 /* 358 * Duplicate a file descriptor to a particular value. 359 * 360 * Note: keep in mind that a potential race condition exists when closing 361 * descriptors from a shared descriptor table (via rfork). 362 */ 363 #ifndef _SYS_SYSPROTO_H_ 364 struct dup2_args { 365 u_int from; 366 u_int to; 367 }; 368 #endif 369 /* ARGSUSED */ 370 int 371 sys_dup2(struct thread *td, struct dup2_args *uap) 372 { 373 374 return (kern_dup(td, FDDUP_FIXED, 0, (int)uap->from, (int)uap->to)); 375 } 376 377 /* 378 * Duplicate a file descriptor. 379 */ 380 #ifndef _SYS_SYSPROTO_H_ 381 struct dup_args { 382 u_int fd; 383 }; 384 #endif 385 /* ARGSUSED */ 386 int 387 sys_dup(struct thread *td, struct dup_args *uap) 388 { 389 390 return (kern_dup(td, FDDUP_NORMAL, 0, (int)uap->fd, 0)); 391 } 392 393 /* 394 * The file control system call. 395 */ 396 #ifndef _SYS_SYSPROTO_H_ 397 struct fcntl_args { 398 int fd; 399 int cmd; 400 long arg; 401 }; 402 #endif 403 /* ARGSUSED */ 404 int 405 sys_fcntl(struct thread *td, struct fcntl_args *uap) 406 { 407 408 return (kern_fcntl_freebsd(td, uap->fd, uap->cmd, uap->arg)); 409 } 410 411 int 412 kern_fcntl_freebsd(struct thread *td, int fd, int cmd, long arg) 413 { 414 struct flock fl; 415 struct __oflock ofl; 416 intptr_t arg1; 417 int error, newcmd; 418 419 error = 0; 420 newcmd = cmd; 421 switch (cmd) { 422 case F_OGETLK: 423 case F_OSETLK: 424 case F_OSETLKW: 425 /* 426 * Convert old flock structure to new. 427 */ 428 error = copyin((void *)(intptr_t)arg, &ofl, sizeof(ofl)); 429 fl.l_start = ofl.l_start; 430 fl.l_len = ofl.l_len; 431 fl.l_pid = ofl.l_pid; 432 fl.l_type = ofl.l_type; 433 fl.l_whence = ofl.l_whence; 434 fl.l_sysid = 0; 435 436 switch (cmd) { 437 case F_OGETLK: 438 newcmd = F_GETLK; 439 break; 440 case F_OSETLK: 441 newcmd = F_SETLK; 442 break; 443 case F_OSETLKW: 444 newcmd = F_SETLKW; 445 break; 446 } 447 arg1 = (intptr_t)&fl; 448 break; 449 case F_GETLK: 450 case F_SETLK: 451 case F_SETLKW: 452 case F_SETLK_REMOTE: 453 error = copyin((void *)(intptr_t)arg, &fl, sizeof(fl)); 454 arg1 = (intptr_t)&fl; 455 break; 456 default: 457 arg1 = arg; 458 break; 459 } 460 if (error) 461 return (error); 462 error = kern_fcntl(td, fd, newcmd, arg1); 463 if (error) 464 return (error); 465 if (cmd == F_OGETLK) { 466 ofl.l_start = fl.l_start; 467 ofl.l_len = fl.l_len; 468 ofl.l_pid = fl.l_pid; 469 ofl.l_type = fl.l_type; 470 ofl.l_whence = fl.l_whence; 471 error = copyout(&ofl, (void *)(intptr_t)arg, sizeof(ofl)); 472 } else if (cmd == F_GETLK) { 473 error = copyout(&fl, (void *)(intptr_t)arg, sizeof(fl)); 474 } 475 return (error); 476 } 477 478 int 479 kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) 480 { 481 struct filedesc *fdp; 482 struct flock *flp; 483 struct file *fp, *fp2; 484 struct filedescent *fde; 485 struct proc *p; 486 struct vnode *vp; 487 cap_rights_t rights; 488 int error, flg, tmp; 489 uint64_t bsize; 490 off_t foffset; 491 492 error = 0; 493 flg = F_POSIX; 494 p = td->td_proc; 495 fdp = p->p_fd; 496 497 AUDIT_ARG_FD(cmd); 498 AUDIT_ARG_CMD(cmd); 499 switch (cmd) { 500 case F_DUPFD: 501 tmp = arg; 502 error = kern_dup(td, FDDUP_FCNTL, 0, fd, tmp); 503 break; 504 505 case F_DUPFD_CLOEXEC: 506 tmp = arg; 507 error = kern_dup(td, FDDUP_FCNTL, FDDUP_FLAG_CLOEXEC, fd, tmp); 508 break; 509 510 case F_DUP2FD: 511 tmp = arg; 512 error = kern_dup(td, FDDUP_FIXED, 0, fd, tmp); 513 break; 514 515 case F_DUP2FD_CLOEXEC: 516 tmp = arg; 517 error = kern_dup(td, FDDUP_FIXED, FDDUP_FLAG_CLOEXEC, fd, tmp); 518 break; 519 520 case F_GETFD: 521 error = EBADF; 522 FILEDESC_SLOCK(fdp); 523 fde = fdeget_locked(fdp, fd); 524 if (fde != NULL) { 525 td->td_retval[0] = 526 (fde->fde_flags & UF_EXCLOSE) ? FD_CLOEXEC : 0; 527 error = 0; 528 } 529 FILEDESC_SUNLOCK(fdp); 530 break; 531 532 case F_SETFD: 533 error = EBADF; 534 FILEDESC_XLOCK(fdp); 535 fde = fdeget_locked(fdp, fd); 536 if (fde != NULL) { 537 fde->fde_flags = (fde->fde_flags & ~UF_EXCLOSE) | 538 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0); 539 error = 0; 540 } 541 FILEDESC_XUNLOCK(fdp); 542 break; 543 544 case F_GETFL: 545 error = fget_fcntl(td, fd, 546 cap_rights_init(&rights, CAP_FCNTL), F_GETFL, &fp); 547 if (error != 0) 548 break; 549 td->td_retval[0] = OFLAGS(fp->f_flag); 550 fdrop(fp, td); 551 break; 552 553 case F_SETFL: 554 error = fget_fcntl(td, fd, 555 cap_rights_init(&rights, CAP_FCNTL), F_SETFL, &fp); 556 if (error != 0) 557 break; 558 do { 559 tmp = flg = fp->f_flag; 560 tmp &= ~FCNTLFLAGS; 561 tmp |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS; 562 } while(atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0); 563 tmp = fp->f_flag & FNONBLOCK; 564 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 565 if (error != 0) { 566 fdrop(fp, td); 567 break; 568 } 569 tmp = fp->f_flag & FASYNC; 570 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); 571 if (error == 0) { 572 fdrop(fp, td); 573 break; 574 } 575 atomic_clear_int(&fp->f_flag, FNONBLOCK); 576 tmp = 0; 577 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 578 fdrop(fp, td); 579 break; 580 581 case F_GETOWN: 582 error = fget_fcntl(td, fd, 583 cap_rights_init(&rights, CAP_FCNTL), F_GETOWN, &fp); 584 if (error != 0) 585 break; 586 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td); 587 if (error == 0) 588 td->td_retval[0] = tmp; 589 fdrop(fp, td); 590 break; 591 592 case F_SETOWN: 593 error = fget_fcntl(td, fd, 594 cap_rights_init(&rights, CAP_FCNTL), F_SETOWN, &fp); 595 if (error != 0) 596 break; 597 tmp = arg; 598 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td); 599 fdrop(fp, td); 600 break; 601 602 case F_SETLK_REMOTE: 603 error = priv_check(td, PRIV_NFS_LOCKD); 604 if (error) 605 return (error); 606 flg = F_REMOTE; 607 goto do_setlk; 608 609 case F_SETLKW: 610 flg |= F_WAIT; 611 /* FALLTHROUGH F_SETLK */ 612 613 case F_SETLK: 614 do_setlk: 615 cap_rights_init(&rights, CAP_FLOCK); 616 error = fget_unlocked(fdp, fd, &rights, &fp, NULL); 617 if (error != 0) 618 break; 619 if (fp->f_type != DTYPE_VNODE) { 620 error = EBADF; 621 fdrop(fp, td); 622 break; 623 } 624 625 flp = (struct flock *)arg; 626 if (flp->l_whence == SEEK_CUR) { 627 foffset = foffset_get(fp); 628 if (foffset < 0 || 629 (flp->l_start > 0 && 630 foffset > OFF_MAX - flp->l_start)) { 631 error = EOVERFLOW; 632 fdrop(fp, td); 633 break; 634 } 635 flp->l_start += foffset; 636 } 637 638 vp = fp->f_vnode; 639 switch (flp->l_type) { 640 case F_RDLCK: 641 if ((fp->f_flag & FREAD) == 0) { 642 error = EBADF; 643 break; 644 } 645 PROC_LOCK(p->p_leader); 646 p->p_leader->p_flag |= P_ADVLOCK; 647 PROC_UNLOCK(p->p_leader); 648 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 649 flp, flg); 650 break; 651 case F_WRLCK: 652 if ((fp->f_flag & FWRITE) == 0) { 653 error = EBADF; 654 break; 655 } 656 PROC_LOCK(p->p_leader); 657 p->p_leader->p_flag |= P_ADVLOCK; 658 PROC_UNLOCK(p->p_leader); 659 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 660 flp, flg); 661 break; 662 case F_UNLCK: 663 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 664 flp, flg); 665 break; 666 case F_UNLCKSYS: 667 /* 668 * Temporary api for testing remote lock 669 * infrastructure. 670 */ 671 if (flg != F_REMOTE) { 672 error = EINVAL; 673 break; 674 } 675 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 676 F_UNLCKSYS, flp, flg); 677 break; 678 default: 679 error = EINVAL; 680 break; 681 } 682 if (error != 0 || flp->l_type == F_UNLCK || 683 flp->l_type == F_UNLCKSYS) { 684 fdrop(fp, td); 685 break; 686 } 687 688 /* 689 * Check for a race with close. 690 * 691 * The vnode is now advisory locked (or unlocked, but this case 692 * is not really important) as the caller requested. 693 * We had to drop the filedesc lock, so we need to recheck if 694 * the descriptor is still valid, because if it was closed 695 * in the meantime we need to remove advisory lock from the 696 * vnode - close on any descriptor leading to an advisory 697 * locked vnode, removes that lock. 698 * We will return 0 on purpose in that case, as the result of 699 * successful advisory lock might have been externally visible 700 * already. This is fine - effectively we pretend to the caller 701 * that the closing thread was a bit slower and that the 702 * advisory lock succeeded before the close. 703 */ 704 error = fget_unlocked(fdp, fd, &rights, &fp2, NULL); 705 if (error != 0) { 706 fdrop(fp, td); 707 break; 708 } 709 if (fp != fp2) { 710 flp->l_whence = SEEK_SET; 711 flp->l_start = 0; 712 flp->l_len = 0; 713 flp->l_type = F_UNLCK; 714 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 715 F_UNLCK, flp, F_POSIX); 716 } 717 fdrop(fp, td); 718 fdrop(fp2, td); 719 break; 720 721 case F_GETLK: 722 error = fget_unlocked(fdp, fd, 723 cap_rights_init(&rights, CAP_FLOCK), &fp, NULL); 724 if (error != 0) 725 break; 726 if (fp->f_type != DTYPE_VNODE) { 727 error = EBADF; 728 fdrop(fp, td); 729 break; 730 } 731 flp = (struct flock *)arg; 732 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK && 733 flp->l_type != F_UNLCK) { 734 error = EINVAL; 735 fdrop(fp, td); 736 break; 737 } 738 if (flp->l_whence == SEEK_CUR) { 739 foffset = foffset_get(fp); 740 if ((flp->l_start > 0 && 741 foffset > OFF_MAX - flp->l_start) || 742 (flp->l_start < 0 && 743 foffset < OFF_MIN - flp->l_start)) { 744 error = EOVERFLOW; 745 fdrop(fp, td); 746 break; 747 } 748 flp->l_start += foffset; 749 } 750 vp = fp->f_vnode; 751 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp, 752 F_POSIX); 753 fdrop(fp, td); 754 break; 755 756 case F_RDAHEAD: 757 arg = arg ? 128 * 1024: 0; 758 /* FALLTHROUGH */ 759 case F_READAHEAD: 760 error = fget_unlocked(fdp, fd, 761 cap_rights_init(&rights), &fp, NULL); 762 if (error != 0) 763 break; 764 if (fp->f_type != DTYPE_VNODE) { 765 fdrop(fp, td); 766 error = EBADF; 767 break; 768 } 769 vp = fp->f_vnode; 770 /* 771 * Exclusive lock synchronizes against f_seqcount reads and 772 * writes in sequential_heuristic(). 773 */ 774 error = vn_lock(vp, LK_EXCLUSIVE); 775 if (error != 0) { 776 fdrop(fp, td); 777 break; 778 } 779 if (arg >= 0) { 780 bsize = fp->f_vnode->v_mount->mnt_stat.f_iosize; 781 fp->f_seqcount = (arg + bsize - 1) / bsize; 782 atomic_set_int(&fp->f_flag, FRDAHEAD); 783 } else { 784 atomic_clear_int(&fp->f_flag, FRDAHEAD); 785 } 786 VOP_UNLOCK(vp, 0); 787 fdrop(fp, td); 788 break; 789 790 default: 791 error = EINVAL; 792 break; 793 } 794 return (error); 795 } 796 797 static int 798 getmaxfd(struct thread *td) 799 { 800 801 return (min((int)lim_cur(td, RLIMIT_NOFILE), maxfilesperproc)); 802 } 803 804 /* 805 * Common code for dup, dup2, fcntl(F_DUPFD) and fcntl(F_DUP2FD). 806 */ 807 int 808 kern_dup(struct thread *td, u_int mode, int flags, int old, int new) 809 { 810 struct filedesc *fdp; 811 struct filedescent *oldfde, *newfde; 812 struct proc *p; 813 struct file *delfp; 814 int error, maxfd; 815 816 p = td->td_proc; 817 fdp = p->p_fd; 818 819 MPASS((flags & ~(FDDUP_FLAG_CLOEXEC)) == 0); 820 MPASS(mode < FDDUP_LASTMODE); 821 822 AUDIT_ARG_FD(old); 823 /* XXXRW: if (flags & FDDUP_FIXED) AUDIT_ARG_FD2(new); */ 824 825 /* 826 * Verify we have a valid descriptor to dup from and possibly to 827 * dup to. Unlike dup() and dup2(), fcntl()'s F_DUPFD should 828 * return EINVAL when the new descriptor is out of bounds. 829 */ 830 if (old < 0) 831 return (EBADF); 832 if (new < 0) 833 return (mode == FDDUP_FCNTL ? EINVAL : EBADF); 834 maxfd = getmaxfd(td); 835 if (new >= maxfd) 836 return (mode == FDDUP_FCNTL ? EINVAL : EBADF); 837 838 error = EBADF; 839 FILEDESC_XLOCK(fdp); 840 if (fget_locked(fdp, old) == NULL) 841 goto unlock; 842 if ((mode == FDDUP_FIXED || mode == FDDUP_MUSTREPLACE) && old == new) { 843 td->td_retval[0] = new; 844 if (flags & FDDUP_FLAG_CLOEXEC) 845 fdp->fd_ofiles[new].fde_flags |= UF_EXCLOSE; 846 error = 0; 847 goto unlock; 848 } 849 850 /* 851 * If the caller specified a file descriptor, make sure the file 852 * table is large enough to hold it, and grab it. Otherwise, just 853 * allocate a new descriptor the usual way. 854 */ 855 switch (mode) { 856 case FDDUP_NORMAL: 857 case FDDUP_FCNTL: 858 if ((error = fdalloc(td, new, &new)) != 0) 859 goto unlock; 860 break; 861 case FDDUP_MUSTREPLACE: 862 /* Target file descriptor must exist. */ 863 if (fget_locked(fdp, new) == NULL) 864 goto unlock; 865 break; 866 case FDDUP_FIXED: 867 if (new >= fdp->fd_nfiles) { 868 /* 869 * The resource limits are here instead of e.g. 870 * fdalloc(), because the file descriptor table may be 871 * shared between processes, so we can't really use 872 * racct_add()/racct_sub(). Instead of counting the 873 * number of actually allocated descriptors, just put 874 * the limit on the size of the file descriptor table. 875 */ 876 #ifdef RACCT 877 if (racct_enable) { 878 PROC_LOCK(p); 879 error = racct_set(p, RACCT_NOFILE, new + 1); 880 PROC_UNLOCK(p); 881 if (error != 0) { 882 error = EMFILE; 883 goto unlock; 884 } 885 } 886 #endif 887 fdgrowtable_exp(fdp, new + 1); 888 } 889 if (!fdisused(fdp, new)) 890 fdused(fdp, new); 891 break; 892 default: 893 KASSERT(0, ("%s unsupported mode %d", __func__, mode)); 894 } 895 896 KASSERT(old != new, ("new fd is same as old")); 897 898 oldfde = &fdp->fd_ofiles[old]; 899 fhold(oldfde->fde_file); 900 newfde = &fdp->fd_ofiles[new]; 901 delfp = newfde->fde_file; 902 903 /* 904 * Duplicate the source descriptor. 905 */ 906 #ifdef CAPABILITIES 907 seq_write_begin(&newfde->fde_seq); 908 #endif 909 filecaps_free(&newfde->fde_caps); 910 memcpy(newfde, oldfde, fde_change_size); 911 filecaps_copy(&oldfde->fde_caps, &newfde->fde_caps, true); 912 if ((flags & FDDUP_FLAG_CLOEXEC) != 0) 913 newfde->fde_flags = oldfde->fde_flags | UF_EXCLOSE; 914 else 915 newfde->fde_flags = oldfde->fde_flags & ~UF_EXCLOSE; 916 #ifdef CAPABILITIES 917 seq_write_end(&newfde->fde_seq); 918 #endif 919 td->td_retval[0] = new; 920 921 error = 0; 922 923 if (delfp != NULL) { 924 (void) closefp(fdp, new, delfp, td, 1); 925 FILEDESC_UNLOCK_ASSERT(fdp); 926 } else { 927 unlock: 928 FILEDESC_XUNLOCK(fdp); 929 } 930 931 return (error); 932 } 933 934 /* 935 * If sigio is on the list associated with a process or process group, 936 * disable signalling from the device, remove sigio from the list and 937 * free sigio. 938 */ 939 void 940 funsetown(struct sigio **sigiop) 941 { 942 struct sigio *sigio; 943 944 if (*sigiop == NULL) 945 return; 946 SIGIO_LOCK(); 947 sigio = *sigiop; 948 if (sigio == NULL) { 949 SIGIO_UNLOCK(); 950 return; 951 } 952 *(sigio->sio_myref) = NULL; 953 if ((sigio)->sio_pgid < 0) { 954 struct pgrp *pg = (sigio)->sio_pgrp; 955 PGRP_LOCK(pg); 956 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 957 sigio, sio_pgsigio); 958 PGRP_UNLOCK(pg); 959 } else { 960 struct proc *p = (sigio)->sio_proc; 961 PROC_LOCK(p); 962 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 963 sigio, sio_pgsigio); 964 PROC_UNLOCK(p); 965 } 966 SIGIO_UNLOCK(); 967 crfree(sigio->sio_ucred); 968 free(sigio, M_SIGIO); 969 } 970 971 /* 972 * Free a list of sigio structures. 973 * We only need to lock the SIGIO_LOCK because we have made ourselves 974 * inaccessible to callers of fsetown and therefore do not need to lock 975 * the proc or pgrp struct for the list manipulation. 976 */ 977 void 978 funsetownlst(struct sigiolst *sigiolst) 979 { 980 struct proc *p; 981 struct pgrp *pg; 982 struct sigio *sigio; 983 984 sigio = SLIST_FIRST(sigiolst); 985 if (sigio == NULL) 986 return; 987 p = NULL; 988 pg = NULL; 989 990 /* 991 * Every entry of the list should belong 992 * to a single proc or pgrp. 993 */ 994 if (sigio->sio_pgid < 0) { 995 pg = sigio->sio_pgrp; 996 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED); 997 } else /* if (sigio->sio_pgid > 0) */ { 998 p = sigio->sio_proc; 999 PROC_LOCK_ASSERT(p, MA_NOTOWNED); 1000 } 1001 1002 SIGIO_LOCK(); 1003 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) { 1004 *(sigio->sio_myref) = NULL; 1005 if (pg != NULL) { 1006 KASSERT(sigio->sio_pgid < 0, 1007 ("Proc sigio in pgrp sigio list")); 1008 KASSERT(sigio->sio_pgrp == pg, 1009 ("Bogus pgrp in sigio list")); 1010 PGRP_LOCK(pg); 1011 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio, 1012 sio_pgsigio); 1013 PGRP_UNLOCK(pg); 1014 } else /* if (p != NULL) */ { 1015 KASSERT(sigio->sio_pgid > 0, 1016 ("Pgrp sigio in proc sigio list")); 1017 KASSERT(sigio->sio_proc == p, 1018 ("Bogus proc in sigio list")); 1019 PROC_LOCK(p); 1020 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, 1021 sio_pgsigio); 1022 PROC_UNLOCK(p); 1023 } 1024 SIGIO_UNLOCK(); 1025 crfree(sigio->sio_ucred); 1026 free(sigio, M_SIGIO); 1027 SIGIO_LOCK(); 1028 } 1029 SIGIO_UNLOCK(); 1030 } 1031 1032 /* 1033 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 1034 * 1035 * After permission checking, add a sigio structure to the sigio list for 1036 * the process or process group. 1037 */ 1038 int 1039 fsetown(pid_t pgid, struct sigio **sigiop) 1040 { 1041 struct proc *proc; 1042 struct pgrp *pgrp; 1043 struct sigio *sigio; 1044 int ret; 1045 1046 if (pgid == 0) { 1047 funsetown(sigiop); 1048 return (0); 1049 } 1050 1051 ret = 0; 1052 1053 /* Allocate and fill in the new sigio out of locks. */ 1054 sigio = malloc(sizeof(struct sigio), M_SIGIO, M_WAITOK); 1055 sigio->sio_pgid = pgid; 1056 sigio->sio_ucred = crhold(curthread->td_ucred); 1057 sigio->sio_myref = sigiop; 1058 1059 sx_slock(&proctree_lock); 1060 if (pgid > 0) { 1061 proc = pfind(pgid); 1062 if (proc == NULL) { 1063 ret = ESRCH; 1064 goto fail; 1065 } 1066 1067 /* 1068 * Policy - Don't allow a process to FSETOWN a process 1069 * in another session. 1070 * 1071 * Remove this test to allow maximum flexibility or 1072 * restrict FSETOWN to the current process or process 1073 * group for maximum safety. 1074 */ 1075 PROC_UNLOCK(proc); 1076 if (proc->p_session != curthread->td_proc->p_session) { 1077 ret = EPERM; 1078 goto fail; 1079 } 1080 1081 pgrp = NULL; 1082 } else /* if (pgid < 0) */ { 1083 pgrp = pgfind(-pgid); 1084 if (pgrp == NULL) { 1085 ret = ESRCH; 1086 goto fail; 1087 } 1088 PGRP_UNLOCK(pgrp); 1089 1090 /* 1091 * Policy - Don't allow a process to FSETOWN a process 1092 * in another session. 1093 * 1094 * Remove this test to allow maximum flexibility or 1095 * restrict FSETOWN to the current process or process 1096 * group for maximum safety. 1097 */ 1098 if (pgrp->pg_session != curthread->td_proc->p_session) { 1099 ret = EPERM; 1100 goto fail; 1101 } 1102 1103 proc = NULL; 1104 } 1105 funsetown(sigiop); 1106 if (pgid > 0) { 1107 PROC_LOCK(proc); 1108 /* 1109 * Since funsetownlst() is called without the proctree 1110 * locked, we need to check for P_WEXIT. 1111 * XXX: is ESRCH correct? 1112 */ 1113 if ((proc->p_flag & P_WEXIT) != 0) { 1114 PROC_UNLOCK(proc); 1115 ret = ESRCH; 1116 goto fail; 1117 } 1118 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 1119 sigio->sio_proc = proc; 1120 PROC_UNLOCK(proc); 1121 } else { 1122 PGRP_LOCK(pgrp); 1123 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 1124 sigio->sio_pgrp = pgrp; 1125 PGRP_UNLOCK(pgrp); 1126 } 1127 sx_sunlock(&proctree_lock); 1128 SIGIO_LOCK(); 1129 *sigiop = sigio; 1130 SIGIO_UNLOCK(); 1131 return (0); 1132 1133 fail: 1134 sx_sunlock(&proctree_lock); 1135 crfree(sigio->sio_ucred); 1136 free(sigio, M_SIGIO); 1137 return (ret); 1138 } 1139 1140 /* 1141 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 1142 */ 1143 pid_t 1144 fgetown(sigiop) 1145 struct sigio **sigiop; 1146 { 1147 pid_t pgid; 1148 1149 SIGIO_LOCK(); 1150 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0; 1151 SIGIO_UNLOCK(); 1152 return (pgid); 1153 } 1154 1155 /* 1156 * Function drops the filedesc lock on return. 1157 */ 1158 static int 1159 closefp(struct filedesc *fdp, int fd, struct file *fp, struct thread *td, 1160 int holdleaders) 1161 { 1162 int error; 1163 1164 FILEDESC_XLOCK_ASSERT(fdp); 1165 1166 if (holdleaders) { 1167 if (td->td_proc->p_fdtol != NULL) { 1168 /* 1169 * Ask fdfree() to sleep to ensure that all relevant 1170 * process leaders can be traversed in closef(). 1171 */ 1172 fdp->fd_holdleaderscount++; 1173 } else { 1174 holdleaders = 0; 1175 } 1176 } 1177 1178 /* 1179 * We now hold the fp reference that used to be owned by the 1180 * descriptor array. We have to unlock the FILEDESC *AFTER* 1181 * knote_fdclose to prevent a race of the fd getting opened, a knote 1182 * added, and deleteing a knote for the new fd. 1183 */ 1184 knote_fdclose(td, fd); 1185 1186 /* 1187 * We need to notify mqueue if the object is of type mqueue. 1188 */ 1189 if (fp->f_type == DTYPE_MQUEUE) 1190 mq_fdclose(td, fd, fp); 1191 FILEDESC_XUNLOCK(fdp); 1192 1193 error = closef(fp, td); 1194 if (holdleaders) { 1195 FILEDESC_XLOCK(fdp); 1196 fdp->fd_holdleaderscount--; 1197 if (fdp->fd_holdleaderscount == 0 && 1198 fdp->fd_holdleaderswakeup != 0) { 1199 fdp->fd_holdleaderswakeup = 0; 1200 wakeup(&fdp->fd_holdleaderscount); 1201 } 1202 FILEDESC_XUNLOCK(fdp); 1203 } 1204 return (error); 1205 } 1206 1207 /* 1208 * Close a file descriptor. 1209 */ 1210 #ifndef _SYS_SYSPROTO_H_ 1211 struct close_args { 1212 int fd; 1213 }; 1214 #endif 1215 /* ARGSUSED */ 1216 int 1217 sys_close(struct thread *td, struct close_args *uap) 1218 { 1219 1220 return (kern_close(td, uap->fd)); 1221 } 1222 1223 int 1224 kern_close(struct thread *td, int fd) 1225 { 1226 struct filedesc *fdp; 1227 struct file *fp; 1228 1229 fdp = td->td_proc->p_fd; 1230 1231 AUDIT_SYSCLOSE(td, fd); 1232 1233 FILEDESC_XLOCK(fdp); 1234 if ((fp = fget_locked(fdp, fd)) == NULL) { 1235 FILEDESC_XUNLOCK(fdp); 1236 return (EBADF); 1237 } 1238 fdfree(fdp, fd); 1239 1240 /* closefp() drops the FILEDESC lock for us. */ 1241 return (closefp(fdp, fd, fp, td, 1)); 1242 } 1243 1244 /* 1245 * Close open file descriptors. 1246 */ 1247 #ifndef _SYS_SYSPROTO_H_ 1248 struct closefrom_args { 1249 int lowfd; 1250 }; 1251 #endif 1252 /* ARGSUSED */ 1253 int 1254 sys_closefrom(struct thread *td, struct closefrom_args *uap) 1255 { 1256 struct filedesc *fdp; 1257 int fd; 1258 1259 fdp = td->td_proc->p_fd; 1260 AUDIT_ARG_FD(uap->lowfd); 1261 1262 /* 1263 * Treat negative starting file descriptor values identical to 1264 * closefrom(0) which closes all files. 1265 */ 1266 if (uap->lowfd < 0) 1267 uap->lowfd = 0; 1268 FILEDESC_SLOCK(fdp); 1269 for (fd = uap->lowfd; fd <= fdp->fd_lastfile; fd++) { 1270 if (fdp->fd_ofiles[fd].fde_file != NULL) { 1271 FILEDESC_SUNLOCK(fdp); 1272 (void)kern_close(td, fd); 1273 FILEDESC_SLOCK(fdp); 1274 } 1275 } 1276 FILEDESC_SUNLOCK(fdp); 1277 return (0); 1278 } 1279 1280 #if defined(COMPAT_43) 1281 /* 1282 * Return status information about a file descriptor. 1283 */ 1284 #ifndef _SYS_SYSPROTO_H_ 1285 struct ofstat_args { 1286 int fd; 1287 struct ostat *sb; 1288 }; 1289 #endif 1290 /* ARGSUSED */ 1291 int 1292 ofstat(struct thread *td, struct ofstat_args *uap) 1293 { 1294 struct ostat oub; 1295 struct stat ub; 1296 int error; 1297 1298 error = kern_fstat(td, uap->fd, &ub); 1299 if (error == 0) { 1300 cvtstat(&ub, &oub); 1301 error = copyout(&oub, uap->sb, sizeof(oub)); 1302 } 1303 return (error); 1304 } 1305 #endif /* COMPAT_43 */ 1306 1307 #if defined(COMPAT_FREEBSD11) 1308 int 1309 freebsd11_fstat(struct thread *td, struct freebsd11_fstat_args *uap) 1310 { 1311 struct stat sb; 1312 struct freebsd11_stat osb; 1313 int error; 1314 1315 error = kern_fstat(td, uap->fd, &sb); 1316 if (error != 0) 1317 return (error); 1318 freebsd11_cvtstat(&sb, &osb); 1319 error = copyout(&osb, uap->sb, sizeof(osb)); 1320 return (error); 1321 } 1322 #endif /* COMPAT_FREEBSD11 */ 1323 1324 /* 1325 * Return status information about a file descriptor. 1326 */ 1327 #ifndef _SYS_SYSPROTO_H_ 1328 struct fstat_args { 1329 int fd; 1330 struct stat *sb; 1331 }; 1332 #endif 1333 /* ARGSUSED */ 1334 int 1335 sys_fstat(struct thread *td, struct fstat_args *uap) 1336 { 1337 struct stat ub; 1338 int error; 1339 1340 error = kern_fstat(td, uap->fd, &ub); 1341 if (error == 0) 1342 error = copyout(&ub, uap->sb, sizeof(ub)); 1343 return (error); 1344 } 1345 1346 int 1347 kern_fstat(struct thread *td, int fd, struct stat *sbp) 1348 { 1349 struct file *fp; 1350 cap_rights_t rights; 1351 int error; 1352 1353 AUDIT_ARG_FD(fd); 1354 1355 error = fget(td, fd, cap_rights_init(&rights, CAP_FSTAT), &fp); 1356 if (error != 0) 1357 return (error); 1358 1359 AUDIT_ARG_FILE(td->td_proc, fp); 1360 1361 error = fo_stat(fp, sbp, td->td_ucred, td); 1362 fdrop(fp, td); 1363 #ifdef __STAT_TIME_T_EXT 1364 if (error == 0) { 1365 sbp->st_atim_ext = 0; 1366 sbp->st_mtim_ext = 0; 1367 sbp->st_ctim_ext = 0; 1368 sbp->st_btim_ext = 0; 1369 } 1370 #endif 1371 #ifdef KTRACE 1372 if (error == 0 && KTRPOINT(td, KTR_STRUCT)) 1373 ktrstat(sbp); 1374 #endif 1375 return (error); 1376 } 1377 1378 #if defined(COMPAT_FREEBSD11) 1379 /* 1380 * Return status information about a file descriptor. 1381 */ 1382 #ifndef _SYS_SYSPROTO_H_ 1383 struct freebsd11_nfstat_args { 1384 int fd; 1385 struct nstat *sb; 1386 }; 1387 #endif 1388 /* ARGSUSED */ 1389 int 1390 freebsd11_nfstat(struct thread *td, struct freebsd11_nfstat_args *uap) 1391 { 1392 struct nstat nub; 1393 struct stat ub; 1394 int error; 1395 1396 error = kern_fstat(td, uap->fd, &ub); 1397 if (error == 0) { 1398 freebsd11_cvtnstat(&ub, &nub); 1399 error = copyout(&nub, uap->sb, sizeof(nub)); 1400 } 1401 return (error); 1402 } 1403 #endif /* COMPAT_FREEBSD11 */ 1404 1405 /* 1406 * Return pathconf information about a file descriptor. 1407 */ 1408 #ifndef _SYS_SYSPROTO_H_ 1409 struct fpathconf_args { 1410 int fd; 1411 int name; 1412 }; 1413 #endif 1414 /* ARGSUSED */ 1415 int 1416 sys_fpathconf(struct thread *td, struct fpathconf_args *uap) 1417 { 1418 struct file *fp; 1419 struct vnode *vp; 1420 cap_rights_t rights; 1421 int error; 1422 1423 error = fget(td, uap->fd, cap_rights_init(&rights, CAP_FPATHCONF), &fp); 1424 if (error != 0) 1425 return (error); 1426 1427 if (uap->name == _PC_ASYNC_IO) { 1428 td->td_retval[0] = _POSIX_ASYNCHRONOUS_IO; 1429 goto out; 1430 } 1431 vp = fp->f_vnode; 1432 if (vp != NULL) { 1433 vn_lock(vp, LK_SHARED | LK_RETRY); 1434 error = VOP_PATHCONF(vp, uap->name, td->td_retval); 1435 VOP_UNLOCK(vp, 0); 1436 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) { 1437 if (uap->name != _PC_PIPE_BUF) { 1438 error = EINVAL; 1439 } else { 1440 td->td_retval[0] = PIPE_BUF; 1441 error = 0; 1442 } 1443 } else { 1444 error = EOPNOTSUPP; 1445 } 1446 out: 1447 fdrop(fp, td); 1448 return (error); 1449 } 1450 1451 /* 1452 * Initialize filecaps structure. 1453 */ 1454 void 1455 filecaps_init(struct filecaps *fcaps) 1456 { 1457 1458 bzero(fcaps, sizeof(*fcaps)); 1459 fcaps->fc_nioctls = -1; 1460 } 1461 1462 /* 1463 * Copy filecaps structure allocating memory for ioctls array if needed. 1464 * 1465 * The last parameter indicates whether the fdtable is locked. If it is not and 1466 * ioctls are encountered, copying fails and the caller must lock the table. 1467 * 1468 * Note that if the table was not locked, the caller has to check the relevant 1469 * sequence counter to determine whether the operation was successful. 1470 */ 1471 int 1472 filecaps_copy(const struct filecaps *src, struct filecaps *dst, bool locked) 1473 { 1474 size_t size; 1475 1476 *dst = *src; 1477 if (src->fc_ioctls == NULL) 1478 return (0); 1479 if (!locked) 1480 return (1); 1481 1482 KASSERT(src->fc_nioctls > 0, 1483 ("fc_ioctls != NULL, but fc_nioctls=%hd", src->fc_nioctls)); 1484 1485 size = sizeof(src->fc_ioctls[0]) * src->fc_nioctls; 1486 dst->fc_ioctls = malloc(size, M_FILECAPS, M_WAITOK); 1487 bcopy(src->fc_ioctls, dst->fc_ioctls, size); 1488 return (0); 1489 } 1490 1491 /* 1492 * Move filecaps structure to the new place and clear the old place. 1493 */ 1494 void 1495 filecaps_move(struct filecaps *src, struct filecaps *dst) 1496 { 1497 1498 *dst = *src; 1499 bzero(src, sizeof(*src)); 1500 } 1501 1502 /* 1503 * Fill the given filecaps structure with full rights. 1504 */ 1505 static void 1506 filecaps_fill(struct filecaps *fcaps) 1507 { 1508 1509 CAP_ALL(&fcaps->fc_rights); 1510 fcaps->fc_ioctls = NULL; 1511 fcaps->fc_nioctls = -1; 1512 fcaps->fc_fcntls = CAP_FCNTL_ALL; 1513 } 1514 1515 /* 1516 * Free memory allocated within filecaps structure. 1517 */ 1518 void 1519 filecaps_free(struct filecaps *fcaps) 1520 { 1521 1522 free(fcaps->fc_ioctls, M_FILECAPS); 1523 bzero(fcaps, sizeof(*fcaps)); 1524 } 1525 1526 /* 1527 * Validate the given filecaps structure. 1528 */ 1529 static void 1530 filecaps_validate(const struct filecaps *fcaps, const char *func) 1531 { 1532 1533 KASSERT(cap_rights_is_valid(&fcaps->fc_rights), 1534 ("%s: invalid rights", func)); 1535 KASSERT((fcaps->fc_fcntls & ~CAP_FCNTL_ALL) == 0, 1536 ("%s: invalid fcntls", func)); 1537 KASSERT(fcaps->fc_fcntls == 0 || 1538 cap_rights_is_set(&fcaps->fc_rights, CAP_FCNTL), 1539 ("%s: fcntls without CAP_FCNTL", func)); 1540 KASSERT(fcaps->fc_ioctls != NULL ? fcaps->fc_nioctls > 0 : 1541 (fcaps->fc_nioctls == -1 || fcaps->fc_nioctls == 0), 1542 ("%s: invalid ioctls", func)); 1543 KASSERT(fcaps->fc_nioctls == 0 || 1544 cap_rights_is_set(&fcaps->fc_rights, CAP_IOCTL), 1545 ("%s: ioctls without CAP_IOCTL", func)); 1546 } 1547 1548 static void 1549 fdgrowtable_exp(struct filedesc *fdp, int nfd) 1550 { 1551 int nfd1; 1552 1553 FILEDESC_XLOCK_ASSERT(fdp); 1554 1555 nfd1 = fdp->fd_nfiles * 2; 1556 if (nfd1 < nfd) 1557 nfd1 = nfd; 1558 fdgrowtable(fdp, nfd1); 1559 } 1560 1561 /* 1562 * Grow the file table to accommodate (at least) nfd descriptors. 1563 */ 1564 static void 1565 fdgrowtable(struct filedesc *fdp, int nfd) 1566 { 1567 struct filedesc0 *fdp0; 1568 struct freetable *ft; 1569 struct fdescenttbl *ntable; 1570 struct fdescenttbl *otable; 1571 int nnfiles, onfiles; 1572 NDSLOTTYPE *nmap, *omap; 1573 1574 /* 1575 * If lastfile is -1 this struct filedesc was just allocated and we are 1576 * growing it to accommodate for the one we are going to copy from. There 1577 * is no need to have a lock on this one as it's not visible to anyone. 1578 */ 1579 if (fdp->fd_lastfile != -1) 1580 FILEDESC_XLOCK_ASSERT(fdp); 1581 1582 KASSERT(fdp->fd_nfiles > 0, ("zero-length file table")); 1583 1584 /* save old values */ 1585 onfiles = fdp->fd_nfiles; 1586 otable = fdp->fd_files; 1587 omap = fdp->fd_map; 1588 1589 /* compute the size of the new table */ 1590 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */ 1591 if (nnfiles <= onfiles) 1592 /* the table is already large enough */ 1593 return; 1594 1595 /* 1596 * Allocate a new table. We need enough space for the number of 1597 * entries, file entries themselves and the struct freetable we will use 1598 * when we decommission the table and place it on the freelist. 1599 * We place the struct freetable in the middle so we don't have 1600 * to worry about padding. 1601 */ 1602 ntable = malloc(offsetof(struct fdescenttbl, fdt_ofiles) + 1603 nnfiles * sizeof(ntable->fdt_ofiles[0]) + 1604 sizeof(struct freetable), 1605 M_FILEDESC, M_ZERO | M_WAITOK); 1606 /* copy the old data */ 1607 ntable->fdt_nfiles = nnfiles; 1608 memcpy(ntable->fdt_ofiles, otable->fdt_ofiles, 1609 onfiles * sizeof(ntable->fdt_ofiles[0])); 1610 1611 /* 1612 * Allocate a new map only if the old is not large enough. It will 1613 * grow at a slower rate than the table as it can map more 1614 * entries than the table can hold. 1615 */ 1616 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) { 1617 nmap = malloc(NDSLOTS(nnfiles) * NDSLOTSIZE, M_FILEDESC, 1618 M_ZERO | M_WAITOK); 1619 /* copy over the old data and update the pointer */ 1620 memcpy(nmap, omap, NDSLOTS(onfiles) * sizeof(*omap)); 1621 fdp->fd_map = nmap; 1622 } 1623 1624 /* 1625 * Make sure that ntable is correctly initialized before we replace 1626 * fd_files poiner. Otherwise fget_unlocked() may see inconsistent 1627 * data. 1628 */ 1629 atomic_store_rel_ptr((volatile void *)&fdp->fd_files, (uintptr_t)ntable); 1630 1631 /* 1632 * Do not free the old file table, as some threads may still 1633 * reference entries within it. Instead, place it on a freelist 1634 * which will be processed when the struct filedesc is released. 1635 * 1636 * Note that if onfiles == NDFILE, we're dealing with the original 1637 * static allocation contained within (struct filedesc0 *)fdp, 1638 * which must not be freed. 1639 */ 1640 if (onfiles > NDFILE) { 1641 ft = (struct freetable *)&otable->fdt_ofiles[onfiles]; 1642 fdp0 = (struct filedesc0 *)fdp; 1643 ft->ft_table = otable; 1644 SLIST_INSERT_HEAD(&fdp0->fd_free, ft, ft_next); 1645 } 1646 /* 1647 * The map does not have the same possibility of threads still 1648 * holding references to it. So always free it as long as it 1649 * does not reference the original static allocation. 1650 */ 1651 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE)) 1652 free(omap, M_FILEDESC); 1653 } 1654 1655 /* 1656 * Allocate a file descriptor for the process. 1657 */ 1658 int 1659 fdalloc(struct thread *td, int minfd, int *result) 1660 { 1661 struct proc *p = td->td_proc; 1662 struct filedesc *fdp = p->p_fd; 1663 int fd, maxfd, allocfd; 1664 #ifdef RACCT 1665 int error; 1666 #endif 1667 1668 FILEDESC_XLOCK_ASSERT(fdp); 1669 1670 if (fdp->fd_freefile > minfd) 1671 minfd = fdp->fd_freefile; 1672 1673 maxfd = getmaxfd(td); 1674 1675 /* 1676 * Search the bitmap for a free descriptor starting at minfd. 1677 * If none is found, grow the file table. 1678 */ 1679 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); 1680 if (fd >= maxfd) 1681 return (EMFILE); 1682 if (fd >= fdp->fd_nfiles) { 1683 allocfd = min(fd * 2, maxfd); 1684 #ifdef RACCT 1685 if (racct_enable) { 1686 PROC_LOCK(p); 1687 error = racct_set(p, RACCT_NOFILE, allocfd); 1688 PROC_UNLOCK(p); 1689 if (error != 0) 1690 return (EMFILE); 1691 } 1692 #endif 1693 /* 1694 * fd is already equal to first free descriptor >= minfd, so 1695 * we only need to grow the table and we are done. 1696 */ 1697 fdgrowtable_exp(fdp, allocfd); 1698 } 1699 1700 /* 1701 * Perform some sanity checks, then mark the file descriptor as 1702 * used and return it to the caller. 1703 */ 1704 KASSERT(fd >= 0 && fd < min(maxfd, fdp->fd_nfiles), 1705 ("invalid descriptor %d", fd)); 1706 KASSERT(!fdisused(fdp, fd), 1707 ("fd_first_free() returned non-free descriptor")); 1708 KASSERT(fdp->fd_ofiles[fd].fde_file == NULL, 1709 ("file descriptor isn't free")); 1710 fdused(fdp, fd); 1711 *result = fd; 1712 return (0); 1713 } 1714 1715 /* 1716 * Allocate n file descriptors for the process. 1717 */ 1718 int 1719 fdallocn(struct thread *td, int minfd, int *fds, int n) 1720 { 1721 struct proc *p = td->td_proc; 1722 struct filedesc *fdp = p->p_fd; 1723 int i; 1724 1725 FILEDESC_XLOCK_ASSERT(fdp); 1726 1727 for (i = 0; i < n; i++) 1728 if (fdalloc(td, 0, &fds[i]) != 0) 1729 break; 1730 1731 if (i < n) { 1732 for (i--; i >= 0; i--) 1733 fdunused(fdp, fds[i]); 1734 return (EMFILE); 1735 } 1736 1737 return (0); 1738 } 1739 1740 /* 1741 * Create a new open file structure and allocate a file descriptor for the 1742 * process that refers to it. We add one reference to the file for the 1743 * descriptor table and one reference for resultfp. This is to prevent us 1744 * being preempted and the entry in the descriptor table closed after we 1745 * release the FILEDESC lock. 1746 */ 1747 int 1748 falloc_caps(struct thread *td, struct file **resultfp, int *resultfd, int flags, 1749 struct filecaps *fcaps) 1750 { 1751 struct file *fp; 1752 int error, fd; 1753 1754 error = falloc_noinstall(td, &fp); 1755 if (error) 1756 return (error); /* no reference held on error */ 1757 1758 error = finstall(td, fp, &fd, flags, fcaps); 1759 if (error) { 1760 fdrop(fp, td); /* one reference (fp only) */ 1761 return (error); 1762 } 1763 1764 if (resultfp != NULL) 1765 *resultfp = fp; /* copy out result */ 1766 else 1767 fdrop(fp, td); /* release local reference */ 1768 1769 if (resultfd != NULL) 1770 *resultfd = fd; 1771 1772 return (0); 1773 } 1774 1775 /* 1776 * Create a new open file structure without allocating a file descriptor. 1777 */ 1778 int 1779 falloc_noinstall(struct thread *td, struct file **resultfp) 1780 { 1781 struct file *fp; 1782 int maxuserfiles = maxfiles - (maxfiles / 20); 1783 int openfiles_new; 1784 static struct timeval lastfail; 1785 static int curfail; 1786 1787 KASSERT(resultfp != NULL, ("%s: resultfp == NULL", __func__)); 1788 1789 openfiles_new = atomic_fetchadd_int(&openfiles, 1) + 1; 1790 if ((openfiles_new >= maxuserfiles && 1791 priv_check(td, PRIV_MAXFILES) != 0) || 1792 openfiles_new >= maxfiles) { 1793 atomic_subtract_int(&openfiles, 1); 1794 if (ppsratecheck(&lastfail, &curfail, 1)) { 1795 printf("kern.maxfiles limit exceeded by uid %i, (%s) " 1796 "please see tuning(7).\n", td->td_ucred->cr_ruid, td->td_proc->p_comm); 1797 } 1798 return (ENFILE); 1799 } 1800 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO); 1801 refcount_init(&fp->f_count, 1); 1802 fp->f_cred = crhold(td->td_ucred); 1803 fp->f_ops = &badfileops; 1804 *resultfp = fp; 1805 return (0); 1806 } 1807 1808 /* 1809 * Install a file in a file descriptor table. 1810 */ 1811 void 1812 _finstall(struct filedesc *fdp, struct file *fp, int fd, int flags, 1813 struct filecaps *fcaps) 1814 { 1815 struct filedescent *fde; 1816 1817 MPASS(fp != NULL); 1818 if (fcaps != NULL) 1819 filecaps_validate(fcaps, __func__); 1820 FILEDESC_XLOCK_ASSERT(fdp); 1821 1822 fde = &fdp->fd_ofiles[fd]; 1823 #ifdef CAPABILITIES 1824 seq_write_begin(&fde->fde_seq); 1825 #endif 1826 fde->fde_file = fp; 1827 fde->fde_flags = (flags & O_CLOEXEC) != 0 ? UF_EXCLOSE : 0; 1828 if (fcaps != NULL) 1829 filecaps_move(fcaps, &fde->fde_caps); 1830 else 1831 filecaps_fill(&fde->fde_caps); 1832 #ifdef CAPABILITIES 1833 seq_write_end(&fde->fde_seq); 1834 #endif 1835 } 1836 1837 int 1838 finstall(struct thread *td, struct file *fp, int *fd, int flags, 1839 struct filecaps *fcaps) 1840 { 1841 struct filedesc *fdp = td->td_proc->p_fd; 1842 int error; 1843 1844 MPASS(fd != NULL); 1845 1846 FILEDESC_XLOCK(fdp); 1847 if ((error = fdalloc(td, 0, fd))) { 1848 FILEDESC_XUNLOCK(fdp); 1849 return (error); 1850 } 1851 fhold(fp); 1852 _finstall(fdp, fp, *fd, flags, fcaps); 1853 FILEDESC_XUNLOCK(fdp); 1854 return (0); 1855 } 1856 1857 /* 1858 * Build a new filedesc structure from another. 1859 * Copy the current, root, and jail root vnode references. 1860 * 1861 * If fdp is not NULL, return with it shared locked. 1862 */ 1863 struct filedesc * 1864 fdinit(struct filedesc *fdp, bool prepfiles) 1865 { 1866 struct filedesc0 *newfdp0; 1867 struct filedesc *newfdp; 1868 1869 newfdp0 = uma_zalloc(filedesc0_zone, M_WAITOK | M_ZERO); 1870 newfdp = &newfdp0->fd_fd; 1871 1872 /* Create the file descriptor table. */ 1873 FILEDESC_LOCK_INIT(newfdp); 1874 refcount_init(&newfdp->fd_refcnt, 1); 1875 refcount_init(&newfdp->fd_holdcnt, 1); 1876 newfdp->fd_cmask = CMASK; 1877 newfdp->fd_map = newfdp0->fd_dmap; 1878 newfdp->fd_lastfile = -1; 1879 newfdp->fd_files = (struct fdescenttbl *)&newfdp0->fd_dfiles; 1880 newfdp->fd_files->fdt_nfiles = NDFILE; 1881 1882 if (fdp == NULL) 1883 return (newfdp); 1884 1885 if (prepfiles && fdp->fd_lastfile >= newfdp->fd_nfiles) 1886 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1887 1888 FILEDESC_SLOCK(fdp); 1889 newfdp->fd_cdir = fdp->fd_cdir; 1890 if (newfdp->fd_cdir) 1891 vrefact(newfdp->fd_cdir); 1892 newfdp->fd_rdir = fdp->fd_rdir; 1893 if (newfdp->fd_rdir) 1894 vrefact(newfdp->fd_rdir); 1895 newfdp->fd_jdir = fdp->fd_jdir; 1896 if (newfdp->fd_jdir) 1897 vrefact(newfdp->fd_jdir); 1898 1899 if (!prepfiles) { 1900 FILEDESC_SUNLOCK(fdp); 1901 } else { 1902 while (fdp->fd_lastfile >= newfdp->fd_nfiles) { 1903 FILEDESC_SUNLOCK(fdp); 1904 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1905 FILEDESC_SLOCK(fdp); 1906 } 1907 } 1908 1909 return (newfdp); 1910 } 1911 1912 static struct filedesc * 1913 fdhold(struct proc *p) 1914 { 1915 struct filedesc *fdp; 1916 1917 PROC_LOCK_ASSERT(p, MA_OWNED); 1918 fdp = p->p_fd; 1919 if (fdp != NULL) 1920 refcount_acquire(&fdp->fd_holdcnt); 1921 return (fdp); 1922 } 1923 1924 static void 1925 fddrop(struct filedesc *fdp) 1926 { 1927 1928 if (fdp->fd_holdcnt > 1) { 1929 if (refcount_release(&fdp->fd_holdcnt) == 0) 1930 return; 1931 } 1932 1933 FILEDESC_LOCK_DESTROY(fdp); 1934 uma_zfree(filedesc0_zone, fdp); 1935 } 1936 1937 /* 1938 * Share a filedesc structure. 1939 */ 1940 struct filedesc * 1941 fdshare(struct filedesc *fdp) 1942 { 1943 1944 refcount_acquire(&fdp->fd_refcnt); 1945 return (fdp); 1946 } 1947 1948 /* 1949 * Unshare a filedesc structure, if necessary by making a copy 1950 */ 1951 void 1952 fdunshare(struct thread *td) 1953 { 1954 struct filedesc *tmp; 1955 struct proc *p = td->td_proc; 1956 1957 if (p->p_fd->fd_refcnt == 1) 1958 return; 1959 1960 tmp = fdcopy(p->p_fd); 1961 fdescfree(td); 1962 p->p_fd = tmp; 1963 } 1964 1965 void 1966 fdinstall_remapped(struct thread *td, struct filedesc *fdp) 1967 { 1968 1969 fdescfree(td); 1970 td->td_proc->p_fd = fdp; 1971 } 1972 1973 /* 1974 * Copy a filedesc structure. A NULL pointer in returns a NULL reference, 1975 * this is to ease callers, not catch errors. 1976 */ 1977 struct filedesc * 1978 fdcopy(struct filedesc *fdp) 1979 { 1980 struct filedesc *newfdp; 1981 struct filedescent *nfde, *ofde; 1982 int i; 1983 1984 MPASS(fdp != NULL); 1985 1986 newfdp = fdinit(fdp, true); 1987 /* copy all passable descriptors (i.e. not kqueue) */ 1988 newfdp->fd_freefile = -1; 1989 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1990 ofde = &fdp->fd_ofiles[i]; 1991 if (ofde->fde_file == NULL || 1992 (ofde->fde_file->f_ops->fo_flags & DFLAG_PASSABLE) == 0) { 1993 if (newfdp->fd_freefile == -1) 1994 newfdp->fd_freefile = i; 1995 continue; 1996 } 1997 nfde = &newfdp->fd_ofiles[i]; 1998 *nfde = *ofde; 1999 filecaps_copy(&ofde->fde_caps, &nfde->fde_caps, true); 2000 fhold(nfde->fde_file); 2001 fdused_init(newfdp, i); 2002 newfdp->fd_lastfile = i; 2003 } 2004 if (newfdp->fd_freefile == -1) 2005 newfdp->fd_freefile = i; 2006 newfdp->fd_cmask = fdp->fd_cmask; 2007 FILEDESC_SUNLOCK(fdp); 2008 return (newfdp); 2009 } 2010 2011 /* 2012 * Copies a filedesc structure, while remapping all file descriptors 2013 * stored inside using a translation table. 2014 * 2015 * File descriptors are copied over to the new file descriptor table, 2016 * regardless of whether the close-on-exec flag is set. 2017 */ 2018 int 2019 fdcopy_remapped(struct filedesc *fdp, const int *fds, size_t nfds, 2020 struct filedesc **ret) 2021 { 2022 struct filedesc *newfdp; 2023 struct filedescent *nfde, *ofde; 2024 int error, i; 2025 2026 MPASS(fdp != NULL); 2027 2028 newfdp = fdinit(fdp, true); 2029 if (nfds > fdp->fd_lastfile + 1) { 2030 /* New table cannot be larger than the old one. */ 2031 error = E2BIG; 2032 goto bad; 2033 } 2034 /* Copy all passable descriptors (i.e. not kqueue). */ 2035 newfdp->fd_freefile = nfds; 2036 for (i = 0; i < nfds; ++i) { 2037 if (fds[i] < 0 || fds[i] > fdp->fd_lastfile) { 2038 /* File descriptor out of bounds. */ 2039 error = EBADF; 2040 goto bad; 2041 } 2042 ofde = &fdp->fd_ofiles[fds[i]]; 2043 if (ofde->fde_file == NULL) { 2044 /* Unused file descriptor. */ 2045 error = EBADF; 2046 goto bad; 2047 } 2048 if ((ofde->fde_file->f_ops->fo_flags & DFLAG_PASSABLE) == 0) { 2049 /* File descriptor cannot be passed. */ 2050 error = EINVAL; 2051 goto bad; 2052 } 2053 nfde = &newfdp->fd_ofiles[i]; 2054 *nfde = *ofde; 2055 filecaps_copy(&ofde->fde_caps, &nfde->fde_caps, true); 2056 fhold(nfde->fde_file); 2057 fdused_init(newfdp, i); 2058 newfdp->fd_lastfile = i; 2059 } 2060 newfdp->fd_cmask = fdp->fd_cmask; 2061 FILEDESC_SUNLOCK(fdp); 2062 *ret = newfdp; 2063 return (0); 2064 bad: 2065 FILEDESC_SUNLOCK(fdp); 2066 fdescfree_remapped(newfdp); 2067 return (error); 2068 } 2069 2070 /* 2071 * Clear POSIX style locks. This is only used when fdp looses a reference (i.e. 2072 * one of processes using it exits) and the table used to be shared. 2073 */ 2074 static void 2075 fdclearlocks(struct thread *td) 2076 { 2077 struct filedesc *fdp; 2078 struct filedesc_to_leader *fdtol; 2079 struct flock lf; 2080 struct file *fp; 2081 struct proc *p; 2082 struct vnode *vp; 2083 int i; 2084 2085 p = td->td_proc; 2086 fdp = p->p_fd; 2087 fdtol = p->p_fdtol; 2088 MPASS(fdtol != NULL); 2089 2090 FILEDESC_XLOCK(fdp); 2091 KASSERT(fdtol->fdl_refcount > 0, 2092 ("filedesc_to_refcount botch: fdl_refcount=%d", 2093 fdtol->fdl_refcount)); 2094 if (fdtol->fdl_refcount == 1 && 2095 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 2096 for (i = 0; i <= fdp->fd_lastfile; i++) { 2097 fp = fdp->fd_ofiles[i].fde_file; 2098 if (fp == NULL || fp->f_type != DTYPE_VNODE) 2099 continue; 2100 fhold(fp); 2101 FILEDESC_XUNLOCK(fdp); 2102 lf.l_whence = SEEK_SET; 2103 lf.l_start = 0; 2104 lf.l_len = 0; 2105 lf.l_type = F_UNLCK; 2106 vp = fp->f_vnode; 2107 (void) VOP_ADVLOCK(vp, 2108 (caddr_t)p->p_leader, F_UNLCK, 2109 &lf, F_POSIX); 2110 FILEDESC_XLOCK(fdp); 2111 fdrop(fp, td); 2112 } 2113 } 2114 retry: 2115 if (fdtol->fdl_refcount == 1) { 2116 if (fdp->fd_holdleaderscount > 0 && 2117 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 2118 /* 2119 * close() or kern_dup() has cleared a reference 2120 * in a shared file descriptor table. 2121 */ 2122 fdp->fd_holdleaderswakeup = 1; 2123 sx_sleep(&fdp->fd_holdleaderscount, 2124 FILEDESC_LOCK(fdp), PLOCK, "fdlhold", 0); 2125 goto retry; 2126 } 2127 if (fdtol->fdl_holdcount > 0) { 2128 /* 2129 * Ensure that fdtol->fdl_leader remains 2130 * valid in closef(). 2131 */ 2132 fdtol->fdl_wakeup = 1; 2133 sx_sleep(fdtol, FILEDESC_LOCK(fdp), PLOCK, 2134 "fdlhold", 0); 2135 goto retry; 2136 } 2137 } 2138 fdtol->fdl_refcount--; 2139 if (fdtol->fdl_refcount == 0 && 2140 fdtol->fdl_holdcount == 0) { 2141 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 2142 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 2143 } else 2144 fdtol = NULL; 2145 p->p_fdtol = NULL; 2146 FILEDESC_XUNLOCK(fdp); 2147 if (fdtol != NULL) 2148 free(fdtol, M_FILEDESC_TO_LEADER); 2149 } 2150 2151 /* 2152 * Release a filedesc structure. 2153 */ 2154 static void 2155 fdescfree_fds(struct thread *td, struct filedesc *fdp, bool needclose) 2156 { 2157 struct filedesc0 *fdp0; 2158 struct freetable *ft, *tft; 2159 struct filedescent *fde; 2160 struct file *fp; 2161 int i; 2162 2163 for (i = 0; i <= fdp->fd_lastfile; i++) { 2164 fde = &fdp->fd_ofiles[i]; 2165 fp = fde->fde_file; 2166 if (fp != NULL) { 2167 fdefree_last(fde); 2168 if (needclose) 2169 (void) closef(fp, td); 2170 else 2171 fdrop(fp, td); 2172 } 2173 } 2174 2175 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE)) 2176 free(fdp->fd_map, M_FILEDESC); 2177 if (fdp->fd_nfiles > NDFILE) 2178 free(fdp->fd_files, M_FILEDESC); 2179 2180 fdp0 = (struct filedesc0 *)fdp; 2181 SLIST_FOREACH_SAFE(ft, &fdp0->fd_free, ft_next, tft) 2182 free(ft->ft_table, M_FILEDESC); 2183 2184 fddrop(fdp); 2185 } 2186 2187 void 2188 fdescfree(struct thread *td) 2189 { 2190 struct proc *p; 2191 struct filedesc *fdp; 2192 struct vnode *cdir, *jdir, *rdir; 2193 2194 p = td->td_proc; 2195 fdp = p->p_fd; 2196 MPASS(fdp != NULL); 2197 2198 #ifdef RACCT 2199 if (racct_enable) { 2200 PROC_LOCK(p); 2201 racct_set(p, RACCT_NOFILE, 0); 2202 PROC_UNLOCK(p); 2203 } 2204 #endif 2205 2206 if (p->p_fdtol != NULL) 2207 fdclearlocks(td); 2208 2209 PROC_LOCK(p); 2210 p->p_fd = NULL; 2211 PROC_UNLOCK(p); 2212 2213 if (refcount_release(&fdp->fd_refcnt) == 0) 2214 return; 2215 2216 FILEDESC_XLOCK(fdp); 2217 cdir = fdp->fd_cdir; 2218 fdp->fd_cdir = NULL; 2219 rdir = fdp->fd_rdir; 2220 fdp->fd_rdir = NULL; 2221 jdir = fdp->fd_jdir; 2222 fdp->fd_jdir = NULL; 2223 FILEDESC_XUNLOCK(fdp); 2224 2225 if (cdir != NULL) 2226 vrele(cdir); 2227 if (rdir != NULL) 2228 vrele(rdir); 2229 if (jdir != NULL) 2230 vrele(jdir); 2231 2232 fdescfree_fds(td, fdp, 1); 2233 } 2234 2235 void 2236 fdescfree_remapped(struct filedesc *fdp) 2237 { 2238 2239 if (fdp->fd_cdir != NULL) 2240 vrele(fdp->fd_cdir); 2241 if (fdp->fd_rdir != NULL) 2242 vrele(fdp->fd_rdir); 2243 if (fdp->fd_jdir != NULL) 2244 vrele(fdp->fd_jdir); 2245 2246 fdescfree_fds(curthread, fdp, 0); 2247 } 2248 2249 /* 2250 * For setugid programs, we don't want to people to use that setugidness 2251 * to generate error messages which write to a file which otherwise would 2252 * otherwise be off-limits to the process. We check for filesystems where 2253 * the vnode can change out from under us after execve (like [lin]procfs). 2254 * 2255 * Since fdsetugidsafety calls this only for fd 0, 1 and 2, this check is 2256 * sufficient. We also don't check for setugidness since we know we are. 2257 */ 2258 static bool 2259 is_unsafe(struct file *fp) 2260 { 2261 struct vnode *vp; 2262 2263 if (fp->f_type != DTYPE_VNODE) 2264 return (false); 2265 2266 vp = fp->f_vnode; 2267 return ((vp->v_vflag & VV_PROCDEP) != 0); 2268 } 2269 2270 /* 2271 * Make this setguid thing safe, if at all possible. 2272 */ 2273 void 2274 fdsetugidsafety(struct thread *td) 2275 { 2276 struct filedesc *fdp; 2277 struct file *fp; 2278 int i; 2279 2280 fdp = td->td_proc->p_fd; 2281 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 2282 MPASS(fdp->fd_nfiles >= 3); 2283 for (i = 0; i <= 2; i++) { 2284 fp = fdp->fd_ofiles[i].fde_file; 2285 if (fp != NULL && is_unsafe(fp)) { 2286 FILEDESC_XLOCK(fdp); 2287 knote_fdclose(td, i); 2288 /* 2289 * NULL-out descriptor prior to close to avoid 2290 * a race while close blocks. 2291 */ 2292 fdfree(fdp, i); 2293 FILEDESC_XUNLOCK(fdp); 2294 (void) closef(fp, td); 2295 } 2296 } 2297 } 2298 2299 /* 2300 * If a specific file object occupies a specific file descriptor, close the 2301 * file descriptor entry and drop a reference on the file object. This is a 2302 * convenience function to handle a subsequent error in a function that calls 2303 * falloc() that handles the race that another thread might have closed the 2304 * file descriptor out from under the thread creating the file object. 2305 */ 2306 void 2307 fdclose(struct thread *td, struct file *fp, int idx) 2308 { 2309 struct filedesc *fdp = td->td_proc->p_fd; 2310 2311 FILEDESC_XLOCK(fdp); 2312 if (fdp->fd_ofiles[idx].fde_file == fp) { 2313 fdfree(fdp, idx); 2314 FILEDESC_XUNLOCK(fdp); 2315 fdrop(fp, td); 2316 } else 2317 FILEDESC_XUNLOCK(fdp); 2318 } 2319 2320 /* 2321 * Close any files on exec? 2322 */ 2323 void 2324 fdcloseexec(struct thread *td) 2325 { 2326 struct filedesc *fdp; 2327 struct filedescent *fde; 2328 struct file *fp; 2329 int i; 2330 2331 fdp = td->td_proc->p_fd; 2332 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 2333 for (i = 0; i <= fdp->fd_lastfile; i++) { 2334 fde = &fdp->fd_ofiles[i]; 2335 fp = fde->fde_file; 2336 if (fp != NULL && (fp->f_type == DTYPE_MQUEUE || 2337 (fde->fde_flags & UF_EXCLOSE))) { 2338 FILEDESC_XLOCK(fdp); 2339 fdfree(fdp, i); 2340 (void) closefp(fdp, i, fp, td, 0); 2341 FILEDESC_UNLOCK_ASSERT(fdp); 2342 } 2343 } 2344 } 2345 2346 /* 2347 * It is unsafe for set[ug]id processes to be started with file 2348 * descriptors 0..2 closed, as these descriptors are given implicit 2349 * significance in the Standard C library. fdcheckstd() will create a 2350 * descriptor referencing /dev/null for each of stdin, stdout, and 2351 * stderr that is not already open. 2352 */ 2353 int 2354 fdcheckstd(struct thread *td) 2355 { 2356 struct filedesc *fdp; 2357 register_t save; 2358 int i, error, devnull; 2359 2360 fdp = td->td_proc->p_fd; 2361 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 2362 MPASS(fdp->fd_nfiles >= 3); 2363 devnull = -1; 2364 for (i = 0; i <= 2; i++) { 2365 if (fdp->fd_ofiles[i].fde_file != NULL) 2366 continue; 2367 2368 save = td->td_retval[0]; 2369 if (devnull != -1) { 2370 error = kern_dup(td, FDDUP_FIXED, 0, devnull, i); 2371 } else { 2372 error = kern_openat(td, AT_FDCWD, "/dev/null", 2373 UIO_SYSSPACE, O_RDWR, 0); 2374 if (error == 0) { 2375 devnull = td->td_retval[0]; 2376 KASSERT(devnull == i, ("we didn't get our fd")); 2377 } 2378 } 2379 td->td_retval[0] = save; 2380 if (error != 0) 2381 return (error); 2382 } 2383 return (0); 2384 } 2385 2386 /* 2387 * Internal form of close. Decrement reference count on file structure. 2388 * Note: td may be NULL when closing a file that was being passed in a 2389 * message. 2390 * 2391 * XXXRW: Giant is not required for the caller, but often will be held; this 2392 * makes it moderately likely the Giant will be recursed in the VFS case. 2393 */ 2394 int 2395 closef(struct file *fp, struct thread *td) 2396 { 2397 struct vnode *vp; 2398 struct flock lf; 2399 struct filedesc_to_leader *fdtol; 2400 struct filedesc *fdp; 2401 2402 /* 2403 * POSIX record locking dictates that any close releases ALL 2404 * locks owned by this process. This is handled by setting 2405 * a flag in the unlock to free ONLY locks obeying POSIX 2406 * semantics, and not to free BSD-style file locks. 2407 * If the descriptor was in a message, POSIX-style locks 2408 * aren't passed with the descriptor, and the thread pointer 2409 * will be NULL. Callers should be careful only to pass a 2410 * NULL thread pointer when there really is no owning 2411 * context that might have locks, or the locks will be 2412 * leaked. 2413 */ 2414 if (fp->f_type == DTYPE_VNODE && td != NULL) { 2415 vp = fp->f_vnode; 2416 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 2417 lf.l_whence = SEEK_SET; 2418 lf.l_start = 0; 2419 lf.l_len = 0; 2420 lf.l_type = F_UNLCK; 2421 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader, 2422 F_UNLCK, &lf, F_POSIX); 2423 } 2424 fdtol = td->td_proc->p_fdtol; 2425 if (fdtol != NULL) { 2426 /* 2427 * Handle special case where file descriptor table is 2428 * shared between multiple process leaders. 2429 */ 2430 fdp = td->td_proc->p_fd; 2431 FILEDESC_XLOCK(fdp); 2432 for (fdtol = fdtol->fdl_next; 2433 fdtol != td->td_proc->p_fdtol; 2434 fdtol = fdtol->fdl_next) { 2435 if ((fdtol->fdl_leader->p_flag & 2436 P_ADVLOCK) == 0) 2437 continue; 2438 fdtol->fdl_holdcount++; 2439 FILEDESC_XUNLOCK(fdp); 2440 lf.l_whence = SEEK_SET; 2441 lf.l_start = 0; 2442 lf.l_len = 0; 2443 lf.l_type = F_UNLCK; 2444 vp = fp->f_vnode; 2445 (void) VOP_ADVLOCK(vp, 2446 (caddr_t)fdtol->fdl_leader, F_UNLCK, &lf, 2447 F_POSIX); 2448 FILEDESC_XLOCK(fdp); 2449 fdtol->fdl_holdcount--; 2450 if (fdtol->fdl_holdcount == 0 && 2451 fdtol->fdl_wakeup != 0) { 2452 fdtol->fdl_wakeup = 0; 2453 wakeup(fdtol); 2454 } 2455 } 2456 FILEDESC_XUNLOCK(fdp); 2457 } 2458 } 2459 return (fdrop(fp, td)); 2460 } 2461 2462 /* 2463 * Initialize the file pointer with the specified properties. 2464 * 2465 * The ops are set with release semantics to be certain that the flags, type, 2466 * and data are visible when ops is. This is to prevent ops methods from being 2467 * called with bad data. 2468 */ 2469 void 2470 finit(struct file *fp, u_int flag, short type, void *data, struct fileops *ops) 2471 { 2472 fp->f_data = data; 2473 fp->f_flag = flag; 2474 fp->f_type = type; 2475 atomic_store_rel_ptr((volatile uintptr_t *)&fp->f_ops, (uintptr_t)ops); 2476 } 2477 2478 int 2479 fget_cap_locked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 2480 struct file **fpp, struct filecaps *havecapsp) 2481 { 2482 struct filedescent *fde; 2483 int error; 2484 2485 FILEDESC_LOCK_ASSERT(fdp); 2486 2487 fde = fdeget_locked(fdp, fd); 2488 if (fde == NULL) { 2489 error = EBADF; 2490 goto out; 2491 } 2492 2493 #ifdef CAPABILITIES 2494 error = cap_check(cap_rights_fde(fde), needrightsp); 2495 if (error != 0) 2496 goto out; 2497 #endif 2498 2499 if (havecapsp != NULL) 2500 filecaps_copy(&fde->fde_caps, havecapsp, true); 2501 2502 *fpp = fde->fde_file; 2503 2504 error = 0; 2505 out: 2506 return (error); 2507 } 2508 2509 int 2510 fget_cap(struct thread *td, int fd, cap_rights_t *needrightsp, 2511 struct file **fpp, struct filecaps *havecapsp) 2512 { 2513 struct filedesc *fdp = td->td_proc->p_fd; 2514 int error; 2515 #ifndef CAPABILITIES 2516 error = fget_unlocked(fdp, fd, needrightsp, fpp, NULL); 2517 if (error == 0 && havecapsp != NULL) 2518 filecaps_fill(havecapsp); 2519 #else 2520 struct file *fp; 2521 seq_t seq; 2522 2523 for (;;) { 2524 error = fget_unlocked(fdp, fd, needrightsp, &fp, &seq); 2525 if (error != 0) 2526 return (error); 2527 2528 if (havecapsp != NULL) { 2529 if (!filecaps_copy(&fdp->fd_ofiles[fd].fde_caps, 2530 havecapsp, false)) { 2531 fdrop(fp, td); 2532 goto get_locked; 2533 } 2534 } 2535 2536 if (!fd_modified(fdp, fd, seq)) 2537 break; 2538 fdrop(fp, td); 2539 } 2540 2541 *fpp = fp; 2542 return (0); 2543 2544 get_locked: 2545 FILEDESC_SLOCK(fdp); 2546 error = fget_cap_locked(fdp, fd, needrightsp, fpp, havecapsp); 2547 if (error == 0) 2548 fhold(*fpp); 2549 FILEDESC_SUNLOCK(fdp); 2550 #endif 2551 return (error); 2552 } 2553 2554 int 2555 fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 2556 struct file **fpp, seq_t *seqp) 2557 { 2558 #ifdef CAPABILITIES 2559 struct filedescent *fde; 2560 #endif 2561 struct fdescenttbl *fdt; 2562 struct file *fp; 2563 u_int count; 2564 #ifdef CAPABILITIES 2565 seq_t seq; 2566 cap_rights_t haverights; 2567 int error; 2568 #endif 2569 2570 fdt = fdp->fd_files; 2571 if ((u_int)fd >= fdt->fdt_nfiles) 2572 return (EBADF); 2573 /* 2574 * Fetch the descriptor locklessly. We avoid fdrop() races by 2575 * never raising a refcount above 0. To accomplish this we have 2576 * to use a cmpset loop rather than an atomic_add. The descriptor 2577 * must be re-verified once we acquire a reference to be certain 2578 * that the identity is still correct and we did not lose a race 2579 * due to preemption. 2580 */ 2581 for (;;) { 2582 #ifdef CAPABILITIES 2583 seq = seq_read(fd_seq(fdt, fd)); 2584 fde = &fdt->fdt_ofiles[fd]; 2585 haverights = *cap_rights_fde(fde); 2586 fp = fde->fde_file; 2587 if (!seq_consistent(fd_seq(fdt, fd), seq)) 2588 continue; 2589 #else 2590 fp = fdt->fdt_ofiles[fd].fde_file; 2591 #endif 2592 if (fp == NULL) 2593 return (EBADF); 2594 #ifdef CAPABILITIES 2595 error = cap_check(&haverights, needrightsp); 2596 if (error != 0) 2597 return (error); 2598 #endif 2599 count = fp->f_count; 2600 retry: 2601 if (count == 0) { 2602 /* 2603 * Force a reload. Other thread could reallocate the 2604 * table before this fd was closed, so it possible that 2605 * there is a stale fp pointer in cached version. 2606 */ 2607 fdt = *(struct fdescenttbl * volatile *)&(fdp->fd_files); 2608 continue; 2609 } 2610 /* 2611 * Use an acquire barrier to force re-reading of fdt so it is 2612 * refreshed for verification. 2613 */ 2614 if (atomic_fcmpset_acq_int(&fp->f_count, &count, count + 1) == 0) 2615 goto retry; 2616 fdt = fdp->fd_files; 2617 #ifdef CAPABILITIES 2618 if (seq_consistent_nomb(fd_seq(fdt, fd), seq)) 2619 #else 2620 if (fp == fdt->fdt_ofiles[fd].fde_file) 2621 #endif 2622 break; 2623 fdrop(fp, curthread); 2624 } 2625 *fpp = fp; 2626 if (seqp != NULL) { 2627 #ifdef CAPABILITIES 2628 *seqp = seq; 2629 #endif 2630 } 2631 return (0); 2632 } 2633 2634 /* 2635 * Extract the file pointer associated with the specified descriptor for the 2636 * current user process. 2637 * 2638 * If the descriptor doesn't exist or doesn't match 'flags', EBADF is 2639 * returned. 2640 * 2641 * File's rights will be checked against the capability rights mask. 2642 * 2643 * If an error occurred the non-zero error is returned and *fpp is set to 2644 * NULL. Otherwise *fpp is held and set and zero is returned. Caller is 2645 * responsible for fdrop(). 2646 */ 2647 static __inline int 2648 _fget(struct thread *td, int fd, struct file **fpp, int flags, 2649 cap_rights_t *needrightsp, seq_t *seqp) 2650 { 2651 struct filedesc *fdp; 2652 struct file *fp; 2653 int error; 2654 2655 *fpp = NULL; 2656 fdp = td->td_proc->p_fd; 2657 error = fget_unlocked(fdp, fd, needrightsp, &fp, seqp); 2658 if (error != 0) 2659 return (error); 2660 if (fp->f_ops == &badfileops) { 2661 fdrop(fp, td); 2662 return (EBADF); 2663 } 2664 2665 /* 2666 * FREAD and FWRITE failure return EBADF as per POSIX. 2667 */ 2668 error = 0; 2669 switch (flags) { 2670 case FREAD: 2671 case FWRITE: 2672 if ((fp->f_flag & flags) == 0) 2673 error = EBADF; 2674 break; 2675 case FEXEC: 2676 if ((fp->f_flag & (FREAD | FEXEC)) == 0 || 2677 ((fp->f_flag & FWRITE) != 0)) 2678 error = EBADF; 2679 break; 2680 case 0: 2681 break; 2682 default: 2683 KASSERT(0, ("wrong flags")); 2684 } 2685 2686 if (error != 0) { 2687 fdrop(fp, td); 2688 return (error); 2689 } 2690 2691 *fpp = fp; 2692 return (0); 2693 } 2694 2695 int 2696 fget(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp) 2697 { 2698 2699 return (_fget(td, fd, fpp, 0, rightsp, NULL)); 2700 } 2701 2702 int 2703 fget_mmap(struct thread *td, int fd, cap_rights_t *rightsp, u_char *maxprotp, 2704 struct file **fpp) 2705 { 2706 int error; 2707 #ifndef CAPABILITIES 2708 error = _fget(td, fd, fpp, 0, rightsp, NULL); 2709 if (maxprotp != NULL) 2710 *maxprotp = VM_PROT_ALL; 2711 #else 2712 struct filedesc *fdp = td->td_proc->p_fd; 2713 seq_t seq; 2714 2715 MPASS(cap_rights_is_set(rightsp, CAP_MMAP)); 2716 for (;;) { 2717 error = _fget(td, fd, fpp, 0, rightsp, &seq); 2718 if (error != 0) 2719 return (error); 2720 /* 2721 * If requested, convert capability rights to access flags. 2722 */ 2723 if (maxprotp != NULL) 2724 *maxprotp = cap_rights_to_vmprot(cap_rights(fdp, fd)); 2725 if (!fd_modified(fdp, fd, seq)) 2726 break; 2727 fdrop(*fpp, td); 2728 } 2729 #endif 2730 return (error); 2731 } 2732 2733 int 2734 fget_read(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp) 2735 { 2736 2737 return (_fget(td, fd, fpp, FREAD, rightsp, NULL)); 2738 } 2739 2740 int 2741 fget_write(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp) 2742 { 2743 2744 return (_fget(td, fd, fpp, FWRITE, rightsp, NULL)); 2745 } 2746 2747 int 2748 fget_fcntl(struct thread *td, int fd, cap_rights_t *rightsp, int needfcntl, 2749 struct file **fpp) 2750 { 2751 struct filedesc *fdp = td->td_proc->p_fd; 2752 #ifndef CAPABILITIES 2753 return (fget_unlocked(fdp, fd, rightsp, fpp, NULL)); 2754 #else 2755 int error; 2756 seq_t seq; 2757 2758 MPASS(cap_rights_is_set(rightsp, CAP_FCNTL)); 2759 for (;;) { 2760 error = fget_unlocked(fdp, fd, rightsp, fpp, &seq); 2761 if (error != 0) 2762 return (error); 2763 error = cap_fcntl_check(fdp, fd, needfcntl); 2764 if (!fd_modified(fdp, fd, seq)) 2765 break; 2766 fdrop(*fpp, td); 2767 } 2768 if (error != 0) { 2769 fdrop(*fpp, td); 2770 *fpp = NULL; 2771 } 2772 return (error); 2773 #endif 2774 } 2775 2776 /* 2777 * Like fget() but loads the underlying vnode, or returns an error if the 2778 * descriptor does not represent a vnode. Note that pipes use vnodes but 2779 * never have VM objects. The returned vnode will be vref()'d. 2780 * 2781 * XXX: what about the unused flags ? 2782 */ 2783 static __inline int 2784 _fgetvp(struct thread *td, int fd, int flags, cap_rights_t *needrightsp, 2785 struct vnode **vpp) 2786 { 2787 struct file *fp; 2788 int error; 2789 2790 *vpp = NULL; 2791 error = _fget(td, fd, &fp, flags, needrightsp, NULL); 2792 if (error != 0) 2793 return (error); 2794 if (fp->f_vnode == NULL) { 2795 error = EINVAL; 2796 } else { 2797 *vpp = fp->f_vnode; 2798 vrefact(*vpp); 2799 } 2800 fdrop(fp, td); 2801 2802 return (error); 2803 } 2804 2805 int 2806 fgetvp(struct thread *td, int fd, cap_rights_t *rightsp, struct vnode **vpp) 2807 { 2808 2809 return (_fgetvp(td, fd, 0, rightsp, vpp)); 2810 } 2811 2812 int 2813 fgetvp_rights(struct thread *td, int fd, cap_rights_t *needrightsp, 2814 struct filecaps *havecaps, struct vnode **vpp) 2815 { 2816 struct filedesc *fdp; 2817 struct filecaps caps; 2818 struct file *fp; 2819 int error; 2820 2821 fdp = td->td_proc->p_fd; 2822 error = fget_cap_locked(fdp, fd, needrightsp, &fp, &caps); 2823 if (error != 0) 2824 return (error); 2825 if (fp->f_ops == &badfileops) { 2826 error = EBADF; 2827 goto out; 2828 } 2829 if (fp->f_vnode == NULL) { 2830 error = EINVAL; 2831 goto out; 2832 } 2833 2834 *havecaps = caps; 2835 *vpp = fp->f_vnode; 2836 vrefact(*vpp); 2837 2838 return (0); 2839 out: 2840 filecaps_free(&caps); 2841 return (error); 2842 } 2843 2844 int 2845 fgetvp_read(struct thread *td, int fd, cap_rights_t *rightsp, struct vnode **vpp) 2846 { 2847 2848 return (_fgetvp(td, fd, FREAD, rightsp, vpp)); 2849 } 2850 2851 int 2852 fgetvp_exec(struct thread *td, int fd, cap_rights_t *rightsp, struct vnode **vpp) 2853 { 2854 2855 return (_fgetvp(td, fd, FEXEC, rightsp, vpp)); 2856 } 2857 2858 #ifdef notyet 2859 int 2860 fgetvp_write(struct thread *td, int fd, cap_rights_t *rightsp, 2861 struct vnode **vpp) 2862 { 2863 2864 return (_fgetvp(td, fd, FWRITE, rightsp, vpp)); 2865 } 2866 #endif 2867 2868 /* 2869 * Handle the last reference to a file being closed. 2870 */ 2871 int 2872 _fdrop(struct file *fp, struct thread *td) 2873 { 2874 int error; 2875 2876 if (fp->f_count != 0) 2877 panic("fdrop: count %d", fp->f_count); 2878 error = fo_close(fp, td); 2879 atomic_subtract_int(&openfiles, 1); 2880 crfree(fp->f_cred); 2881 free(fp->f_advice, M_FADVISE); 2882 uma_zfree(file_zone, fp); 2883 2884 return (error); 2885 } 2886 2887 /* 2888 * Apply an advisory lock on a file descriptor. 2889 * 2890 * Just attempt to get a record lock of the requested type on the entire file 2891 * (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2892 */ 2893 #ifndef _SYS_SYSPROTO_H_ 2894 struct flock_args { 2895 int fd; 2896 int how; 2897 }; 2898 #endif 2899 /* ARGSUSED */ 2900 int 2901 sys_flock(struct thread *td, struct flock_args *uap) 2902 { 2903 struct file *fp; 2904 struct vnode *vp; 2905 struct flock lf; 2906 cap_rights_t rights; 2907 int error; 2908 2909 error = fget(td, uap->fd, cap_rights_init(&rights, CAP_FLOCK), &fp); 2910 if (error != 0) 2911 return (error); 2912 if (fp->f_type != DTYPE_VNODE) { 2913 fdrop(fp, td); 2914 return (EOPNOTSUPP); 2915 } 2916 2917 vp = fp->f_vnode; 2918 lf.l_whence = SEEK_SET; 2919 lf.l_start = 0; 2920 lf.l_len = 0; 2921 if (uap->how & LOCK_UN) { 2922 lf.l_type = F_UNLCK; 2923 atomic_clear_int(&fp->f_flag, FHASLOCK); 2924 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 2925 goto done2; 2926 } 2927 if (uap->how & LOCK_EX) 2928 lf.l_type = F_WRLCK; 2929 else if (uap->how & LOCK_SH) 2930 lf.l_type = F_RDLCK; 2931 else { 2932 error = EBADF; 2933 goto done2; 2934 } 2935 atomic_set_int(&fp->f_flag, FHASLOCK); 2936 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 2937 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT); 2938 done2: 2939 fdrop(fp, td); 2940 return (error); 2941 } 2942 /* 2943 * Duplicate the specified descriptor to a free descriptor. 2944 */ 2945 int 2946 dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode, 2947 int openerror, int *indxp) 2948 { 2949 struct filedescent *newfde, *oldfde; 2950 struct file *fp; 2951 int error, indx; 2952 2953 KASSERT(openerror == ENODEV || openerror == ENXIO, 2954 ("unexpected error %d in %s", openerror, __func__)); 2955 2956 /* 2957 * If the to-be-dup'd fd number is greater than the allowed number 2958 * of file descriptors, or the fd to be dup'd has already been 2959 * closed, then reject. 2960 */ 2961 FILEDESC_XLOCK(fdp); 2962 if ((fp = fget_locked(fdp, dfd)) == NULL) { 2963 FILEDESC_XUNLOCK(fdp); 2964 return (EBADF); 2965 } 2966 2967 error = fdalloc(td, 0, &indx); 2968 if (error != 0) { 2969 FILEDESC_XUNLOCK(fdp); 2970 return (error); 2971 } 2972 2973 /* 2974 * There are two cases of interest here. 2975 * 2976 * For ENODEV simply dup (dfd) to file descriptor (indx) and return. 2977 * 2978 * For ENXIO steal away the file structure from (dfd) and store it in 2979 * (indx). (dfd) is effectively closed by this operation. 2980 */ 2981 switch (openerror) { 2982 case ENODEV: 2983 /* 2984 * Check that the mode the file is being opened for is a 2985 * subset of the mode of the existing descriptor. 2986 */ 2987 if (((mode & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) { 2988 fdunused(fdp, indx); 2989 FILEDESC_XUNLOCK(fdp); 2990 return (EACCES); 2991 } 2992 fhold(fp); 2993 newfde = &fdp->fd_ofiles[indx]; 2994 oldfde = &fdp->fd_ofiles[dfd]; 2995 #ifdef CAPABILITIES 2996 seq_write_begin(&newfde->fde_seq); 2997 #endif 2998 memcpy(newfde, oldfde, fde_change_size); 2999 filecaps_copy(&oldfde->fde_caps, &newfde->fde_caps, true); 3000 #ifdef CAPABILITIES 3001 seq_write_end(&newfde->fde_seq); 3002 #endif 3003 break; 3004 case ENXIO: 3005 /* 3006 * Steal away the file pointer from dfd and stuff it into indx. 3007 */ 3008 newfde = &fdp->fd_ofiles[indx]; 3009 oldfde = &fdp->fd_ofiles[dfd]; 3010 #ifdef CAPABILITIES 3011 seq_write_begin(&newfde->fde_seq); 3012 #endif 3013 memcpy(newfde, oldfde, fde_change_size); 3014 oldfde->fde_file = NULL; 3015 fdunused(fdp, dfd); 3016 #ifdef CAPABILITIES 3017 seq_write_end(&newfde->fde_seq); 3018 #endif 3019 break; 3020 } 3021 FILEDESC_XUNLOCK(fdp); 3022 *indxp = indx; 3023 return (0); 3024 } 3025 3026 /* 3027 * This sysctl determines if we will allow a process to chroot(2) if it 3028 * has a directory open: 3029 * 0: disallowed for all processes. 3030 * 1: allowed for processes that were not already chroot(2)'ed. 3031 * 2: allowed for all processes. 3032 */ 3033 3034 static int chroot_allow_open_directories = 1; 3035 3036 SYSCTL_INT(_kern, OID_AUTO, chroot_allow_open_directories, CTLFLAG_RW, 3037 &chroot_allow_open_directories, 0, 3038 "Allow a process to chroot(2) if it has a directory open"); 3039 3040 /* 3041 * Helper function for raised chroot(2) security function: Refuse if 3042 * any filedescriptors are open directories. 3043 */ 3044 static int 3045 chroot_refuse_vdir_fds(struct filedesc *fdp) 3046 { 3047 struct vnode *vp; 3048 struct file *fp; 3049 int fd; 3050 3051 FILEDESC_LOCK_ASSERT(fdp); 3052 3053 for (fd = 0; fd <= fdp->fd_lastfile; fd++) { 3054 fp = fget_locked(fdp, fd); 3055 if (fp == NULL) 3056 continue; 3057 if (fp->f_type == DTYPE_VNODE) { 3058 vp = fp->f_vnode; 3059 if (vp->v_type == VDIR) 3060 return (EPERM); 3061 } 3062 } 3063 return (0); 3064 } 3065 3066 /* 3067 * Common routine for kern_chroot() and jail_attach(). The caller is 3068 * responsible for invoking priv_check() and mac_vnode_check_chroot() to 3069 * authorize this operation. 3070 */ 3071 int 3072 pwd_chroot(struct thread *td, struct vnode *vp) 3073 { 3074 struct filedesc *fdp; 3075 struct vnode *oldvp; 3076 int error; 3077 3078 fdp = td->td_proc->p_fd; 3079 FILEDESC_XLOCK(fdp); 3080 if (chroot_allow_open_directories == 0 || 3081 (chroot_allow_open_directories == 1 && fdp->fd_rdir != rootvnode)) { 3082 error = chroot_refuse_vdir_fds(fdp); 3083 if (error != 0) { 3084 FILEDESC_XUNLOCK(fdp); 3085 return (error); 3086 } 3087 } 3088 oldvp = fdp->fd_rdir; 3089 vrefact(vp); 3090 fdp->fd_rdir = vp; 3091 if (fdp->fd_jdir == NULL) { 3092 vrefact(vp); 3093 fdp->fd_jdir = vp; 3094 } 3095 FILEDESC_XUNLOCK(fdp); 3096 vrele(oldvp); 3097 return (0); 3098 } 3099 3100 void 3101 pwd_chdir(struct thread *td, struct vnode *vp) 3102 { 3103 struct filedesc *fdp; 3104 struct vnode *oldvp; 3105 3106 fdp = td->td_proc->p_fd; 3107 FILEDESC_XLOCK(fdp); 3108 VNASSERT(vp->v_usecount > 0, vp, 3109 ("chdir to a vnode with zero usecount")); 3110 oldvp = fdp->fd_cdir; 3111 fdp->fd_cdir = vp; 3112 FILEDESC_XUNLOCK(fdp); 3113 vrele(oldvp); 3114 } 3115 3116 /* 3117 * Scan all active processes and prisons to see if any of them have a current 3118 * or root directory of `olddp'. If so, replace them with the new mount point. 3119 */ 3120 void 3121 mountcheckdirs(struct vnode *olddp, struct vnode *newdp) 3122 { 3123 struct filedesc *fdp; 3124 struct prison *pr; 3125 struct proc *p; 3126 int nrele; 3127 3128 if (vrefcnt(olddp) == 1) 3129 return; 3130 nrele = 0; 3131 sx_slock(&allproc_lock); 3132 FOREACH_PROC_IN_SYSTEM(p) { 3133 PROC_LOCK(p); 3134 fdp = fdhold(p); 3135 PROC_UNLOCK(p); 3136 if (fdp == NULL) 3137 continue; 3138 FILEDESC_XLOCK(fdp); 3139 if (fdp->fd_cdir == olddp) { 3140 vrefact(newdp); 3141 fdp->fd_cdir = newdp; 3142 nrele++; 3143 } 3144 if (fdp->fd_rdir == olddp) { 3145 vrefact(newdp); 3146 fdp->fd_rdir = newdp; 3147 nrele++; 3148 } 3149 if (fdp->fd_jdir == olddp) { 3150 vrefact(newdp); 3151 fdp->fd_jdir = newdp; 3152 nrele++; 3153 } 3154 FILEDESC_XUNLOCK(fdp); 3155 fddrop(fdp); 3156 } 3157 sx_sunlock(&allproc_lock); 3158 if (rootvnode == olddp) { 3159 vrefact(newdp); 3160 rootvnode = newdp; 3161 nrele++; 3162 } 3163 mtx_lock(&prison0.pr_mtx); 3164 if (prison0.pr_root == olddp) { 3165 vrefact(newdp); 3166 prison0.pr_root = newdp; 3167 nrele++; 3168 } 3169 mtx_unlock(&prison0.pr_mtx); 3170 sx_slock(&allprison_lock); 3171 TAILQ_FOREACH(pr, &allprison, pr_list) { 3172 mtx_lock(&pr->pr_mtx); 3173 if (pr->pr_root == olddp) { 3174 vrefact(newdp); 3175 pr->pr_root = newdp; 3176 nrele++; 3177 } 3178 mtx_unlock(&pr->pr_mtx); 3179 } 3180 sx_sunlock(&allprison_lock); 3181 while (nrele--) 3182 vrele(olddp); 3183 } 3184 3185 struct filedesc_to_leader * 3186 filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader) 3187 { 3188 struct filedesc_to_leader *fdtol; 3189 3190 fdtol = malloc(sizeof(struct filedesc_to_leader), 3191 M_FILEDESC_TO_LEADER, M_WAITOK); 3192 fdtol->fdl_refcount = 1; 3193 fdtol->fdl_holdcount = 0; 3194 fdtol->fdl_wakeup = 0; 3195 fdtol->fdl_leader = leader; 3196 if (old != NULL) { 3197 FILEDESC_XLOCK(fdp); 3198 fdtol->fdl_next = old->fdl_next; 3199 fdtol->fdl_prev = old; 3200 old->fdl_next = fdtol; 3201 fdtol->fdl_next->fdl_prev = fdtol; 3202 FILEDESC_XUNLOCK(fdp); 3203 } else { 3204 fdtol->fdl_next = fdtol; 3205 fdtol->fdl_prev = fdtol; 3206 } 3207 return (fdtol); 3208 } 3209 3210 static int 3211 sysctl_kern_proc_nfds(SYSCTL_HANDLER_ARGS) 3212 { 3213 struct filedesc *fdp; 3214 int i, count, slots; 3215 3216 if (*(int *)arg1 != 0) 3217 return (EINVAL); 3218 3219 fdp = curproc->p_fd; 3220 count = 0; 3221 FILEDESC_SLOCK(fdp); 3222 slots = NDSLOTS(fdp->fd_lastfile + 1); 3223 for (i = 0; i < slots; i++) 3224 count += bitcountl(fdp->fd_map[i]); 3225 FILEDESC_SUNLOCK(fdp); 3226 3227 return (SYSCTL_OUT(req, &count, sizeof(count))); 3228 } 3229 3230 static SYSCTL_NODE(_kern_proc, KERN_PROC_NFDS, nfds, 3231 CTLFLAG_RD|CTLFLAG_CAPRD|CTLFLAG_MPSAFE, sysctl_kern_proc_nfds, 3232 "Number of open file descriptors"); 3233 3234 /* 3235 * Get file structures globally. 3236 */ 3237 static int 3238 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 3239 { 3240 struct xfile xf; 3241 struct filedesc *fdp; 3242 struct file *fp; 3243 struct proc *p; 3244 int error, n; 3245 3246 error = sysctl_wire_old_buffer(req, 0); 3247 if (error != 0) 3248 return (error); 3249 if (req->oldptr == NULL) { 3250 n = 0; 3251 sx_slock(&allproc_lock); 3252 FOREACH_PROC_IN_SYSTEM(p) { 3253 PROC_LOCK(p); 3254 if (p->p_state == PRS_NEW) { 3255 PROC_UNLOCK(p); 3256 continue; 3257 } 3258 fdp = fdhold(p); 3259 PROC_UNLOCK(p); 3260 if (fdp == NULL) 3261 continue; 3262 /* overestimates sparse tables. */ 3263 if (fdp->fd_lastfile > 0) 3264 n += fdp->fd_lastfile; 3265 fddrop(fdp); 3266 } 3267 sx_sunlock(&allproc_lock); 3268 return (SYSCTL_OUT(req, 0, n * sizeof(xf))); 3269 } 3270 error = 0; 3271 bzero(&xf, sizeof(xf)); 3272 xf.xf_size = sizeof(xf); 3273 sx_slock(&allproc_lock); 3274 FOREACH_PROC_IN_SYSTEM(p) { 3275 PROC_LOCK(p); 3276 if (p->p_state == PRS_NEW) { 3277 PROC_UNLOCK(p); 3278 continue; 3279 } 3280 if (p_cansee(req->td, p) != 0) { 3281 PROC_UNLOCK(p); 3282 continue; 3283 } 3284 xf.xf_pid = p->p_pid; 3285 xf.xf_uid = p->p_ucred->cr_uid; 3286 fdp = fdhold(p); 3287 PROC_UNLOCK(p); 3288 if (fdp == NULL) 3289 continue; 3290 FILEDESC_SLOCK(fdp); 3291 for (n = 0; fdp->fd_refcnt > 0 && n <= fdp->fd_lastfile; ++n) { 3292 if ((fp = fdp->fd_ofiles[n].fde_file) == NULL) 3293 continue; 3294 xf.xf_fd = n; 3295 xf.xf_file = fp; 3296 xf.xf_data = fp->f_data; 3297 xf.xf_vnode = fp->f_vnode; 3298 xf.xf_type = fp->f_type; 3299 xf.xf_count = fp->f_count; 3300 xf.xf_msgcount = 0; 3301 xf.xf_offset = foffset_get(fp); 3302 xf.xf_flag = fp->f_flag; 3303 error = SYSCTL_OUT(req, &xf, sizeof(xf)); 3304 if (error) 3305 break; 3306 } 3307 FILEDESC_SUNLOCK(fdp); 3308 fddrop(fdp); 3309 if (error) 3310 break; 3311 } 3312 sx_sunlock(&allproc_lock); 3313 return (error); 3314 } 3315 3316 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE, 3317 0, 0, sysctl_kern_file, "S,xfile", "Entire file table"); 3318 3319 #ifdef KINFO_FILE_SIZE 3320 CTASSERT(sizeof(struct kinfo_file) == KINFO_FILE_SIZE); 3321 #endif 3322 3323 static int 3324 xlate_fflags(int fflags) 3325 { 3326 static const struct { 3327 int fflag; 3328 int kf_fflag; 3329 } fflags_table[] = { 3330 { FAPPEND, KF_FLAG_APPEND }, 3331 { FASYNC, KF_FLAG_ASYNC }, 3332 { FFSYNC, KF_FLAG_FSYNC }, 3333 { FHASLOCK, KF_FLAG_HASLOCK }, 3334 { FNONBLOCK, KF_FLAG_NONBLOCK }, 3335 { FREAD, KF_FLAG_READ }, 3336 { FWRITE, KF_FLAG_WRITE }, 3337 { O_CREAT, KF_FLAG_CREAT }, 3338 { O_DIRECT, KF_FLAG_DIRECT }, 3339 { O_EXCL, KF_FLAG_EXCL }, 3340 { O_EXEC, KF_FLAG_EXEC }, 3341 { O_EXLOCK, KF_FLAG_EXLOCK }, 3342 { O_NOFOLLOW, KF_FLAG_NOFOLLOW }, 3343 { O_SHLOCK, KF_FLAG_SHLOCK }, 3344 { O_TRUNC, KF_FLAG_TRUNC } 3345 }; 3346 unsigned int i; 3347 int kflags; 3348 3349 kflags = 0; 3350 for (i = 0; i < nitems(fflags_table); i++) 3351 if (fflags & fflags_table[i].fflag) 3352 kflags |= fflags_table[i].kf_fflag; 3353 return (kflags); 3354 } 3355 3356 /* Trim unused data from kf_path by truncating the structure size. */ 3357 static void 3358 pack_kinfo(struct kinfo_file *kif) 3359 { 3360 3361 kif->kf_structsize = offsetof(struct kinfo_file, kf_path) + 3362 strlen(kif->kf_path) + 1; 3363 kif->kf_structsize = roundup(kif->kf_structsize, sizeof(uint64_t)); 3364 } 3365 3366 static void 3367 export_file_to_kinfo(struct file *fp, int fd, cap_rights_t *rightsp, 3368 struct kinfo_file *kif, struct filedesc *fdp, int flags) 3369 { 3370 int error; 3371 3372 bzero(kif, sizeof(*kif)); 3373 3374 /* Set a default type to allow for empty fill_kinfo() methods. */ 3375 kif->kf_type = KF_TYPE_UNKNOWN; 3376 kif->kf_flags = xlate_fflags(fp->f_flag); 3377 if (rightsp != NULL) 3378 kif->kf_cap_rights = *rightsp; 3379 else 3380 cap_rights_init(&kif->kf_cap_rights); 3381 kif->kf_fd = fd; 3382 kif->kf_ref_count = fp->f_count; 3383 kif->kf_offset = foffset_get(fp); 3384 3385 /* 3386 * This may drop the filedesc lock, so the 'fp' cannot be 3387 * accessed after this call. 3388 */ 3389 error = fo_fill_kinfo(fp, kif, fdp); 3390 if (error == 0) 3391 kif->kf_status |= KF_ATTR_VALID; 3392 if ((flags & KERN_FILEDESC_PACK_KINFO) != 0) 3393 pack_kinfo(kif); 3394 else 3395 kif->kf_structsize = roundup2(sizeof(*kif), sizeof(uint64_t)); 3396 } 3397 3398 static void 3399 export_vnode_to_kinfo(struct vnode *vp, int fd, int fflags, 3400 struct kinfo_file *kif, int flags) 3401 { 3402 int error; 3403 3404 bzero(kif, sizeof(*kif)); 3405 3406 kif->kf_type = KF_TYPE_VNODE; 3407 error = vn_fill_kinfo_vnode(vp, kif); 3408 if (error == 0) 3409 kif->kf_status |= KF_ATTR_VALID; 3410 kif->kf_flags = xlate_fflags(fflags); 3411 cap_rights_init(&kif->kf_cap_rights); 3412 kif->kf_fd = fd; 3413 kif->kf_ref_count = -1; 3414 kif->kf_offset = -1; 3415 if ((flags & KERN_FILEDESC_PACK_KINFO) != 0) 3416 pack_kinfo(kif); 3417 else 3418 kif->kf_structsize = roundup2(sizeof(*kif), sizeof(uint64_t)); 3419 vrele(vp); 3420 } 3421 3422 struct export_fd_buf { 3423 struct filedesc *fdp; 3424 struct sbuf *sb; 3425 ssize_t remainder; 3426 struct kinfo_file kif; 3427 int flags; 3428 }; 3429 3430 static int 3431 export_kinfo_to_sb(struct export_fd_buf *efbuf) 3432 { 3433 struct kinfo_file *kif; 3434 3435 kif = &efbuf->kif; 3436 if (efbuf->remainder != -1) { 3437 if (efbuf->remainder < kif->kf_structsize) { 3438 /* Terminate export. */ 3439 efbuf->remainder = 0; 3440 return (0); 3441 } 3442 efbuf->remainder -= kif->kf_structsize; 3443 } 3444 return (sbuf_bcat(efbuf->sb, kif, kif->kf_structsize) == 0 ? 0 : ENOMEM); 3445 } 3446 3447 static int 3448 export_file_to_sb(struct file *fp, int fd, cap_rights_t *rightsp, 3449 struct export_fd_buf *efbuf) 3450 { 3451 int error; 3452 3453 if (efbuf->remainder == 0) 3454 return (0); 3455 export_file_to_kinfo(fp, fd, rightsp, &efbuf->kif, efbuf->fdp, 3456 efbuf->flags); 3457 FILEDESC_SUNLOCK(efbuf->fdp); 3458 error = export_kinfo_to_sb(efbuf); 3459 FILEDESC_SLOCK(efbuf->fdp); 3460 return (error); 3461 } 3462 3463 static int 3464 export_vnode_to_sb(struct vnode *vp, int fd, int fflags, 3465 struct export_fd_buf *efbuf) 3466 { 3467 int error; 3468 3469 if (efbuf->remainder == 0) 3470 return (0); 3471 if (efbuf->fdp != NULL) 3472 FILEDESC_SUNLOCK(efbuf->fdp); 3473 export_vnode_to_kinfo(vp, fd, fflags, &efbuf->kif, efbuf->flags); 3474 error = export_kinfo_to_sb(efbuf); 3475 if (efbuf->fdp != NULL) 3476 FILEDESC_SLOCK(efbuf->fdp); 3477 return (error); 3478 } 3479 3480 /* 3481 * Store a process file descriptor information to sbuf. 3482 * 3483 * Takes a locked proc as argument, and returns with the proc unlocked. 3484 */ 3485 int 3486 kern_proc_filedesc_out(struct proc *p, struct sbuf *sb, ssize_t maxlen, 3487 int flags) 3488 { 3489 struct file *fp; 3490 struct filedesc *fdp; 3491 struct export_fd_buf *efbuf; 3492 struct vnode *cttyvp, *textvp, *tracevp; 3493 int error, i; 3494 cap_rights_t rights; 3495 3496 PROC_LOCK_ASSERT(p, MA_OWNED); 3497 3498 /* ktrace vnode */ 3499 tracevp = p->p_tracevp; 3500 if (tracevp != NULL) 3501 vrefact(tracevp); 3502 /* text vnode */ 3503 textvp = p->p_textvp; 3504 if (textvp != NULL) 3505 vrefact(textvp); 3506 /* Controlling tty. */ 3507 cttyvp = NULL; 3508 if (p->p_pgrp != NULL && p->p_pgrp->pg_session != NULL) { 3509 cttyvp = p->p_pgrp->pg_session->s_ttyvp; 3510 if (cttyvp != NULL) 3511 vrefact(cttyvp); 3512 } 3513 fdp = fdhold(p); 3514 PROC_UNLOCK(p); 3515 efbuf = malloc(sizeof(*efbuf), M_TEMP, M_WAITOK); 3516 efbuf->fdp = NULL; 3517 efbuf->sb = sb; 3518 efbuf->remainder = maxlen; 3519 efbuf->flags = flags; 3520 if (tracevp != NULL) 3521 export_vnode_to_sb(tracevp, KF_FD_TYPE_TRACE, FREAD | FWRITE, 3522 efbuf); 3523 if (textvp != NULL) 3524 export_vnode_to_sb(textvp, KF_FD_TYPE_TEXT, FREAD, efbuf); 3525 if (cttyvp != NULL) 3526 export_vnode_to_sb(cttyvp, KF_FD_TYPE_CTTY, FREAD | FWRITE, 3527 efbuf); 3528 error = 0; 3529 if (fdp == NULL) 3530 goto fail; 3531 efbuf->fdp = fdp; 3532 FILEDESC_SLOCK(fdp); 3533 /* working directory */ 3534 if (fdp->fd_cdir != NULL) { 3535 vrefact(fdp->fd_cdir); 3536 export_vnode_to_sb(fdp->fd_cdir, KF_FD_TYPE_CWD, FREAD, efbuf); 3537 } 3538 /* root directory */ 3539 if (fdp->fd_rdir != NULL) { 3540 vrefact(fdp->fd_rdir); 3541 export_vnode_to_sb(fdp->fd_rdir, KF_FD_TYPE_ROOT, FREAD, efbuf); 3542 } 3543 /* jail directory */ 3544 if (fdp->fd_jdir != NULL) { 3545 vrefact(fdp->fd_jdir); 3546 export_vnode_to_sb(fdp->fd_jdir, KF_FD_TYPE_JAIL, FREAD, efbuf); 3547 } 3548 for (i = 0; fdp->fd_refcnt > 0 && i <= fdp->fd_lastfile; i++) { 3549 if ((fp = fdp->fd_ofiles[i].fde_file) == NULL) 3550 continue; 3551 #ifdef CAPABILITIES 3552 rights = *cap_rights(fdp, i); 3553 #else /* !CAPABILITIES */ 3554 cap_rights_init(&rights); 3555 #endif 3556 /* 3557 * Create sysctl entry. It is OK to drop the filedesc 3558 * lock inside of export_file_to_sb() as we will 3559 * re-validate and re-evaluate its properties when the 3560 * loop continues. 3561 */ 3562 error = export_file_to_sb(fp, i, &rights, efbuf); 3563 if (error != 0 || efbuf->remainder == 0) 3564 break; 3565 } 3566 FILEDESC_SUNLOCK(fdp); 3567 fddrop(fdp); 3568 fail: 3569 free(efbuf, M_TEMP); 3570 return (error); 3571 } 3572 3573 #define FILEDESC_SBUF_SIZE (sizeof(struct kinfo_file) * 5) 3574 3575 /* 3576 * Get per-process file descriptors for use by procstat(1), et al. 3577 */ 3578 static int 3579 sysctl_kern_proc_filedesc(SYSCTL_HANDLER_ARGS) 3580 { 3581 struct sbuf sb; 3582 struct proc *p; 3583 ssize_t maxlen; 3584 int error, error2, *name; 3585 3586 name = (int *)arg1; 3587 3588 sbuf_new_for_sysctl(&sb, NULL, FILEDESC_SBUF_SIZE, req); 3589 sbuf_clear_flags(&sb, SBUF_INCLUDENUL); 3590 error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p); 3591 if (error != 0) { 3592 sbuf_delete(&sb); 3593 return (error); 3594 } 3595 maxlen = req->oldptr != NULL ? req->oldlen : -1; 3596 error = kern_proc_filedesc_out(p, &sb, maxlen, 3597 KERN_FILEDESC_PACK_KINFO); 3598 error2 = sbuf_finish(&sb); 3599 sbuf_delete(&sb); 3600 return (error != 0 ? error : error2); 3601 } 3602 3603 #ifdef COMPAT_FREEBSD7 3604 #ifdef KINFO_OFILE_SIZE 3605 CTASSERT(sizeof(struct kinfo_ofile) == KINFO_OFILE_SIZE); 3606 #endif 3607 3608 static void 3609 kinfo_to_okinfo(struct kinfo_file *kif, struct kinfo_ofile *okif) 3610 { 3611 3612 okif->kf_structsize = sizeof(*okif); 3613 okif->kf_type = kif->kf_type; 3614 okif->kf_fd = kif->kf_fd; 3615 okif->kf_ref_count = kif->kf_ref_count; 3616 okif->kf_flags = kif->kf_flags & (KF_FLAG_READ | KF_FLAG_WRITE | 3617 KF_FLAG_APPEND | KF_FLAG_ASYNC | KF_FLAG_FSYNC | KF_FLAG_NONBLOCK | 3618 KF_FLAG_DIRECT | KF_FLAG_HASLOCK); 3619 okif->kf_offset = kif->kf_offset; 3620 if (kif->kf_type == KF_TYPE_VNODE) 3621 okif->kf_vnode_type = kif->kf_un.kf_file.kf_file_type; 3622 else 3623 okif->kf_vnode_type = KF_VTYPE_VNON; 3624 strlcpy(okif->kf_path, kif->kf_path, sizeof(okif->kf_path)); 3625 if (kif->kf_type == KF_TYPE_SOCKET) { 3626 okif->kf_sock_domain = kif->kf_un.kf_sock.kf_sock_domain0; 3627 okif->kf_sock_type = kif->kf_un.kf_sock.kf_sock_type0; 3628 okif->kf_sock_protocol = kif->kf_un.kf_sock.kf_sock_protocol0; 3629 okif->kf_sa_local = kif->kf_un.kf_sock.kf_sa_local; 3630 okif->kf_sa_peer = kif->kf_un.kf_sock.kf_sa_peer; 3631 } else { 3632 okif->kf_sa_local.ss_family = AF_UNSPEC; 3633 okif->kf_sa_peer.ss_family = AF_UNSPEC; 3634 } 3635 } 3636 3637 static int 3638 export_vnode_for_osysctl(struct vnode *vp, int type, struct kinfo_file *kif, 3639 struct kinfo_ofile *okif, struct filedesc *fdp, struct sysctl_req *req) 3640 { 3641 int error; 3642 3643 vrefact(vp); 3644 FILEDESC_SUNLOCK(fdp); 3645 export_vnode_to_kinfo(vp, type, 0, kif, KERN_FILEDESC_PACK_KINFO); 3646 kinfo_to_okinfo(kif, okif); 3647 error = SYSCTL_OUT(req, okif, sizeof(*okif)); 3648 FILEDESC_SLOCK(fdp); 3649 return (error); 3650 } 3651 3652 /* 3653 * Get per-process file descriptors for use by procstat(1), et al. 3654 */ 3655 static int 3656 sysctl_kern_proc_ofiledesc(SYSCTL_HANDLER_ARGS) 3657 { 3658 struct kinfo_ofile *okif; 3659 struct kinfo_file *kif; 3660 struct filedesc *fdp; 3661 int error, i, *name; 3662 struct file *fp; 3663 struct proc *p; 3664 3665 name = (int *)arg1; 3666 error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p); 3667 if (error != 0) 3668 return (error); 3669 fdp = fdhold(p); 3670 PROC_UNLOCK(p); 3671 if (fdp == NULL) 3672 return (ENOENT); 3673 kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK); 3674 okif = malloc(sizeof(*okif), M_TEMP, M_WAITOK); 3675 FILEDESC_SLOCK(fdp); 3676 if (fdp->fd_cdir != NULL) 3677 export_vnode_for_osysctl(fdp->fd_cdir, KF_FD_TYPE_CWD, kif, 3678 okif, fdp, req); 3679 if (fdp->fd_rdir != NULL) 3680 export_vnode_for_osysctl(fdp->fd_rdir, KF_FD_TYPE_ROOT, kif, 3681 okif, fdp, req); 3682 if (fdp->fd_jdir != NULL) 3683 export_vnode_for_osysctl(fdp->fd_jdir, KF_FD_TYPE_JAIL, kif, 3684 okif, fdp, req); 3685 for (i = 0; fdp->fd_refcnt > 0 && i <= fdp->fd_lastfile; i++) { 3686 if ((fp = fdp->fd_ofiles[i].fde_file) == NULL) 3687 continue; 3688 export_file_to_kinfo(fp, i, NULL, kif, fdp, 3689 KERN_FILEDESC_PACK_KINFO); 3690 FILEDESC_SUNLOCK(fdp); 3691 kinfo_to_okinfo(kif, okif); 3692 error = SYSCTL_OUT(req, okif, sizeof(*okif)); 3693 FILEDESC_SLOCK(fdp); 3694 if (error) 3695 break; 3696 } 3697 FILEDESC_SUNLOCK(fdp); 3698 fddrop(fdp); 3699 free(kif, M_TEMP); 3700 free(okif, M_TEMP); 3701 return (0); 3702 } 3703 3704 static SYSCTL_NODE(_kern_proc, KERN_PROC_OFILEDESC, ofiledesc, 3705 CTLFLAG_RD|CTLFLAG_MPSAFE, sysctl_kern_proc_ofiledesc, 3706 "Process ofiledesc entries"); 3707 #endif /* COMPAT_FREEBSD7 */ 3708 3709 int 3710 vntype_to_kinfo(int vtype) 3711 { 3712 struct { 3713 int vtype; 3714 int kf_vtype; 3715 } vtypes_table[] = { 3716 { VBAD, KF_VTYPE_VBAD }, 3717 { VBLK, KF_VTYPE_VBLK }, 3718 { VCHR, KF_VTYPE_VCHR }, 3719 { VDIR, KF_VTYPE_VDIR }, 3720 { VFIFO, KF_VTYPE_VFIFO }, 3721 { VLNK, KF_VTYPE_VLNK }, 3722 { VNON, KF_VTYPE_VNON }, 3723 { VREG, KF_VTYPE_VREG }, 3724 { VSOCK, KF_VTYPE_VSOCK } 3725 }; 3726 unsigned int i; 3727 3728 /* 3729 * Perform vtype translation. 3730 */ 3731 for (i = 0; i < nitems(vtypes_table); i++) 3732 if (vtypes_table[i].vtype == vtype) 3733 return (vtypes_table[i].kf_vtype); 3734 3735 return (KF_VTYPE_UNKNOWN); 3736 } 3737 3738 static SYSCTL_NODE(_kern_proc, KERN_PROC_FILEDESC, filedesc, 3739 CTLFLAG_RD|CTLFLAG_MPSAFE, sysctl_kern_proc_filedesc, 3740 "Process filedesc entries"); 3741 3742 /* 3743 * Store a process current working directory information to sbuf. 3744 * 3745 * Takes a locked proc as argument, and returns with the proc unlocked. 3746 */ 3747 int 3748 kern_proc_cwd_out(struct proc *p, struct sbuf *sb, ssize_t maxlen) 3749 { 3750 struct filedesc *fdp; 3751 struct export_fd_buf *efbuf; 3752 int error; 3753 3754 PROC_LOCK_ASSERT(p, MA_OWNED); 3755 3756 fdp = fdhold(p); 3757 PROC_UNLOCK(p); 3758 if (fdp == NULL) 3759 return (EINVAL); 3760 3761 efbuf = malloc(sizeof(*efbuf), M_TEMP, M_WAITOK); 3762 efbuf->fdp = fdp; 3763 efbuf->sb = sb; 3764 efbuf->remainder = maxlen; 3765 3766 FILEDESC_SLOCK(fdp); 3767 if (fdp->fd_cdir == NULL) 3768 error = EINVAL; 3769 else { 3770 vrefact(fdp->fd_cdir); 3771 error = export_vnode_to_sb(fdp->fd_cdir, KF_FD_TYPE_CWD, 3772 FREAD, efbuf); 3773 } 3774 FILEDESC_SUNLOCK(fdp); 3775 fddrop(fdp); 3776 free(efbuf, M_TEMP); 3777 return (error); 3778 } 3779 3780 /* 3781 * Get per-process current working directory. 3782 */ 3783 static int 3784 sysctl_kern_proc_cwd(SYSCTL_HANDLER_ARGS) 3785 { 3786 struct sbuf sb; 3787 struct proc *p; 3788 ssize_t maxlen; 3789 int error, error2, *name; 3790 3791 name = (int *)arg1; 3792 3793 sbuf_new_for_sysctl(&sb, NULL, sizeof(struct kinfo_file), req); 3794 sbuf_clear_flags(&sb, SBUF_INCLUDENUL); 3795 error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p); 3796 if (error != 0) { 3797 sbuf_delete(&sb); 3798 return (error); 3799 } 3800 maxlen = req->oldptr != NULL ? req->oldlen : -1; 3801 error = kern_proc_cwd_out(p, &sb, maxlen); 3802 error2 = sbuf_finish(&sb); 3803 sbuf_delete(&sb); 3804 return (error != 0 ? error : error2); 3805 } 3806 3807 static SYSCTL_NODE(_kern_proc, KERN_PROC_CWD, cwd, CTLFLAG_RD|CTLFLAG_MPSAFE, 3808 sysctl_kern_proc_cwd, "Process current working directory"); 3809 3810 #ifdef DDB 3811 /* 3812 * For the purposes of debugging, generate a human-readable string for the 3813 * file type. 3814 */ 3815 static const char * 3816 file_type_to_name(short type) 3817 { 3818 3819 switch (type) { 3820 case 0: 3821 return ("zero"); 3822 case DTYPE_VNODE: 3823 return ("vnod"); 3824 case DTYPE_SOCKET: 3825 return ("sock"); 3826 case DTYPE_PIPE: 3827 return ("pipe"); 3828 case DTYPE_FIFO: 3829 return ("fifo"); 3830 case DTYPE_KQUEUE: 3831 return ("kque"); 3832 case DTYPE_CRYPTO: 3833 return ("crpt"); 3834 case DTYPE_MQUEUE: 3835 return ("mque"); 3836 case DTYPE_SHM: 3837 return ("shm"); 3838 case DTYPE_SEM: 3839 return ("ksem"); 3840 default: 3841 return ("unkn"); 3842 } 3843 } 3844 3845 /* 3846 * For the purposes of debugging, identify a process (if any, perhaps one of 3847 * many) that references the passed file in its file descriptor array. Return 3848 * NULL if none. 3849 */ 3850 static struct proc * 3851 file_to_first_proc(struct file *fp) 3852 { 3853 struct filedesc *fdp; 3854 struct proc *p; 3855 int n; 3856 3857 FOREACH_PROC_IN_SYSTEM(p) { 3858 if (p->p_state == PRS_NEW) 3859 continue; 3860 fdp = p->p_fd; 3861 if (fdp == NULL) 3862 continue; 3863 for (n = 0; n <= fdp->fd_lastfile; n++) { 3864 if (fp == fdp->fd_ofiles[n].fde_file) 3865 return (p); 3866 } 3867 } 3868 return (NULL); 3869 } 3870 3871 static void 3872 db_print_file(struct file *fp, int header) 3873 { 3874 struct proc *p; 3875 3876 if (header) 3877 db_printf("%8s %4s %8s %8s %4s %5s %6s %8s %5s %12s\n", 3878 "File", "Type", "Data", "Flag", "GCFl", "Count", 3879 "MCount", "Vnode", "FPID", "FCmd"); 3880 p = file_to_first_proc(fp); 3881 db_printf("%8p %4s %8p %08x %04x %5d %6d %8p %5d %12s\n", fp, 3882 file_type_to_name(fp->f_type), fp->f_data, fp->f_flag, 3883 0, fp->f_count, 0, fp->f_vnode, 3884 p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-"); 3885 } 3886 3887 DB_SHOW_COMMAND(file, db_show_file) 3888 { 3889 struct file *fp; 3890 3891 if (!have_addr) { 3892 db_printf("usage: show file <addr>\n"); 3893 return; 3894 } 3895 fp = (struct file *)addr; 3896 db_print_file(fp, 1); 3897 } 3898 3899 DB_SHOW_COMMAND(files, db_show_files) 3900 { 3901 struct filedesc *fdp; 3902 struct file *fp; 3903 struct proc *p; 3904 int header; 3905 int n; 3906 3907 header = 1; 3908 FOREACH_PROC_IN_SYSTEM(p) { 3909 if (p->p_state == PRS_NEW) 3910 continue; 3911 if ((fdp = p->p_fd) == NULL) 3912 continue; 3913 for (n = 0; n <= fdp->fd_lastfile; ++n) { 3914 if ((fp = fdp->fd_ofiles[n].fde_file) == NULL) 3915 continue; 3916 db_print_file(fp, header); 3917 header = 0; 3918 } 3919 } 3920 } 3921 #endif 3922 3923 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 3924 &maxfilesperproc, 0, "Maximum files allowed open per process"); 3925 3926 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 3927 &maxfiles, 0, "Maximum number of files"); 3928 3929 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 3930 __DEVOLATILE(int *, &openfiles), 0, "System-wide number of open files"); 3931 3932 /* ARGSUSED*/ 3933 static void 3934 filelistinit(void *dummy) 3935 { 3936 3937 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL, 3938 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 3939 filedesc0_zone = uma_zcreate("filedesc0", sizeof(struct filedesc0), 3940 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 3941 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF); 3942 } 3943 SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL); 3944 3945 /*-------------------------------------------------------------------*/ 3946 3947 static int 3948 badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred, 3949 int flags, struct thread *td) 3950 { 3951 3952 return (EBADF); 3953 } 3954 3955 static int 3956 badfo_truncate(struct file *fp, off_t length, struct ucred *active_cred, 3957 struct thread *td) 3958 { 3959 3960 return (EINVAL); 3961 } 3962 3963 static int 3964 badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 3965 struct thread *td) 3966 { 3967 3968 return (EBADF); 3969 } 3970 3971 static int 3972 badfo_poll(struct file *fp, int events, struct ucred *active_cred, 3973 struct thread *td) 3974 { 3975 3976 return (0); 3977 } 3978 3979 static int 3980 badfo_kqfilter(struct file *fp, struct knote *kn) 3981 { 3982 3983 return (EBADF); 3984 } 3985 3986 static int 3987 badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 3988 struct thread *td) 3989 { 3990 3991 return (EBADF); 3992 } 3993 3994 static int 3995 badfo_close(struct file *fp, struct thread *td) 3996 { 3997 3998 return (0); 3999 } 4000 4001 static int 4002 badfo_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 4003 struct thread *td) 4004 { 4005 4006 return (EBADF); 4007 } 4008 4009 static int 4010 badfo_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 4011 struct thread *td) 4012 { 4013 4014 return (EBADF); 4015 } 4016 4017 static int 4018 badfo_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio, 4019 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags, 4020 struct thread *td) 4021 { 4022 4023 return (EBADF); 4024 } 4025 4026 static int 4027 badfo_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 4028 { 4029 4030 return (0); 4031 } 4032 4033 struct fileops badfileops = { 4034 .fo_read = badfo_readwrite, 4035 .fo_write = badfo_readwrite, 4036 .fo_truncate = badfo_truncate, 4037 .fo_ioctl = badfo_ioctl, 4038 .fo_poll = badfo_poll, 4039 .fo_kqfilter = badfo_kqfilter, 4040 .fo_stat = badfo_stat, 4041 .fo_close = badfo_close, 4042 .fo_chmod = badfo_chmod, 4043 .fo_chown = badfo_chown, 4044 .fo_sendfile = badfo_sendfile, 4045 .fo_fill_kinfo = badfo_fill_kinfo, 4046 }; 4047 4048 int 4049 invfo_rdwr(struct file *fp, struct uio *uio, struct ucred *active_cred, 4050 int flags, struct thread *td) 4051 { 4052 4053 return (EOPNOTSUPP); 4054 } 4055 4056 int 4057 invfo_truncate(struct file *fp, off_t length, struct ucred *active_cred, 4058 struct thread *td) 4059 { 4060 4061 return (EINVAL); 4062 } 4063 4064 int 4065 invfo_ioctl(struct file *fp, u_long com, void *data, 4066 struct ucred *active_cred, struct thread *td) 4067 { 4068 4069 return (ENOTTY); 4070 } 4071 4072 int 4073 invfo_poll(struct file *fp, int events, struct ucred *active_cred, 4074 struct thread *td) 4075 { 4076 4077 return (poll_no_poll(events)); 4078 } 4079 4080 int 4081 invfo_kqfilter(struct file *fp, struct knote *kn) 4082 { 4083 4084 return (EINVAL); 4085 } 4086 4087 int 4088 invfo_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 4089 struct thread *td) 4090 { 4091 4092 return (EINVAL); 4093 } 4094 4095 int 4096 invfo_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 4097 struct thread *td) 4098 { 4099 4100 return (EINVAL); 4101 } 4102 4103 int 4104 invfo_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio, 4105 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags, 4106 struct thread *td) 4107 { 4108 4109 return (EINVAL); 4110 } 4111 4112 /*-------------------------------------------------------------------*/ 4113 4114 /* 4115 * File Descriptor pseudo-device driver (/dev/fd/). 4116 * 4117 * Opening minor device N dup()s the file (if any) connected to file 4118 * descriptor N belonging to the calling process. Note that this driver 4119 * consists of only the ``open()'' routine, because all subsequent 4120 * references to this file will be direct to the other driver. 4121 * 4122 * XXX: we could give this one a cloning event handler if necessary. 4123 */ 4124 4125 /* ARGSUSED */ 4126 static int 4127 fdopen(struct cdev *dev, int mode, int type, struct thread *td) 4128 { 4129 4130 /* 4131 * XXX Kludge: set curthread->td_dupfd to contain the value of the 4132 * the file descriptor being sought for duplication. The error 4133 * return ensures that the vnode for this device will be released 4134 * by vn_open. Open will detect this special error and take the 4135 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 4136 * will simply report the error. 4137 */ 4138 td->td_dupfd = dev2unit(dev); 4139 return (ENODEV); 4140 } 4141 4142 static struct cdevsw fildesc_cdevsw = { 4143 .d_version = D_VERSION, 4144 .d_open = fdopen, 4145 .d_name = "FD", 4146 }; 4147 4148 static void 4149 fildesc_drvinit(void *unused) 4150 { 4151 struct cdev *dev; 4152 4153 dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 0, NULL, 4154 UID_ROOT, GID_WHEEL, 0666, "fd/0"); 4155 make_dev_alias(dev, "stdin"); 4156 dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 1, NULL, 4157 UID_ROOT, GID_WHEEL, 0666, "fd/1"); 4158 make_dev_alias(dev, "stdout"); 4159 dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 2, NULL, 4160 UID_ROOT, GID_WHEEL, 0666, "fd/2"); 4161 make_dev_alias(dev, "stderr"); 4162 } 4163 4164 SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL); 4165