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/socketvar.h> 71 #include <sys/kdb.h> 72 #include <sys/stat.h> 73 #include <sys/sx.h> 74 #include <sys/syscallsubr.h> 75 #include <sys/sysctl.h> 76 #include <sys/sysproto.h> 77 #include <sys/unistd.h> 78 #include <sys/user.h> 79 #include <sys/vnode.h> 80 #ifdef KTRACE 81 #include <sys/ktrace.h> 82 #endif 83 84 #include <net/vnet.h> 85 86 #include <security/audit/audit.h> 87 88 #include <vm/uma.h> 89 #include <vm/vm.h> 90 91 #include <ddb/ddb.h> 92 93 static MALLOC_DEFINE(M_FILEDESC, "filedesc", "Open file descriptor table"); 94 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "filedesc_to_leader", 95 "file desc to leader structures"); 96 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 97 MALLOC_DEFINE(M_FILECAPS, "filecaps", "descriptor capabilities"); 98 99 MALLOC_DECLARE(M_FADVISE); 100 101 static uma_zone_t file_zone; 102 static uma_zone_t filedesc0_zone; 103 104 static int closefp(struct filedesc *fdp, int fd, struct file *fp, 105 struct thread *td, int holdleaders); 106 static int fd_first_free(struct filedesc *fdp, int low, int size); 107 static int fd_last_used(struct filedesc *fdp, int size); 108 static void fdgrowtable(struct filedesc *fdp, int nfd); 109 static void fdgrowtable_exp(struct filedesc *fdp, int nfd); 110 static void fdunused(struct filedesc *fdp, int fd); 111 static void fdused(struct filedesc *fdp, int fd); 112 static int getmaxfd(struct thread *td); 113 114 /* 115 * Each process has: 116 * 117 * - An array of open file descriptors (fd_ofiles) 118 * - An array of file flags (fd_ofileflags) 119 * - A bitmap recording which descriptors are in use (fd_map) 120 * 121 * A process starts out with NDFILE descriptors. The value of NDFILE has 122 * been selected based the historical limit of 20 open files, and an 123 * assumption that the majority of processes, especially short-lived 124 * processes like shells, will never need more. 125 * 126 * If this initial allocation is exhausted, a larger descriptor table and 127 * map are allocated dynamically, and the pointers in the process's struct 128 * filedesc are updated to point to those. This is repeated every time 129 * the process runs out of file descriptors (provided it hasn't hit its 130 * resource limit). 131 * 132 * Since threads may hold references to individual descriptor table 133 * entries, the tables are never freed. Instead, they are placed on a 134 * linked list and freed only when the struct filedesc is released. 135 */ 136 #define NDFILE 20 137 #define NDSLOTSIZE sizeof(NDSLOTTYPE) 138 #define NDENTRIES (NDSLOTSIZE * __CHAR_BIT) 139 #define NDSLOT(x) ((x) / NDENTRIES) 140 #define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES)) 141 #define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES) 142 143 /* 144 * SLIST entry used to keep track of ofiles which must be reclaimed when 145 * the process exits. 146 */ 147 struct freetable { 148 struct fdescenttbl *ft_table; 149 SLIST_ENTRY(freetable) ft_next; 150 }; 151 152 /* 153 * Initial allocation: a filedesc structure + the head of SLIST used to 154 * keep track of old ofiles + enough space for NDFILE descriptors. 155 */ 156 157 struct fdescenttbl0 { 158 int fdt_nfiles; 159 struct filedescent fdt_ofiles[NDFILE]; 160 }; 161 162 struct filedesc0 { 163 struct filedesc fd_fd; 164 SLIST_HEAD(, freetable) fd_free; 165 struct fdescenttbl0 fd_dfiles; 166 NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)]; 167 }; 168 169 /* 170 * Descriptor management. 171 */ 172 volatile int openfiles; /* actual number of open files */ 173 struct mtx sigio_lock; /* mtx to protect pointers to sigio */ 174 void (*mq_fdclose)(struct thread *td, int fd, struct file *fp); 175 176 /* 177 * If low >= size, just return low. Otherwise find the first zero bit in the 178 * given bitmap, starting at low and not exceeding size - 1. Return size if 179 * not found. 180 */ 181 static int 182 fd_first_free(struct filedesc *fdp, int low, int size) 183 { 184 NDSLOTTYPE *map = fdp->fd_map; 185 NDSLOTTYPE mask; 186 int off, maxoff; 187 188 if (low >= size) 189 return (low); 190 191 off = NDSLOT(low); 192 if (low % NDENTRIES) { 193 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES))); 194 if ((mask &= ~map[off]) != 0UL) 195 return (off * NDENTRIES + ffsl(mask) - 1); 196 ++off; 197 } 198 for (maxoff = NDSLOTS(size); off < maxoff; ++off) 199 if (map[off] != ~0UL) 200 return (off * NDENTRIES + ffsl(~map[off]) - 1); 201 return (size); 202 } 203 204 /* 205 * Find the highest non-zero bit in the given bitmap, starting at 0 and 206 * not exceeding size - 1. Return -1 if not found. 207 */ 208 static int 209 fd_last_used(struct filedesc *fdp, int size) 210 { 211 NDSLOTTYPE *map = fdp->fd_map; 212 NDSLOTTYPE mask; 213 int off, minoff; 214 215 off = NDSLOT(size); 216 if (size % NDENTRIES) { 217 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES)); 218 if ((mask &= map[off]) != 0) 219 return (off * NDENTRIES + flsl(mask) - 1); 220 --off; 221 } 222 for (minoff = NDSLOT(0); off >= minoff; --off) 223 if (map[off] != 0) 224 return (off * NDENTRIES + flsl(map[off]) - 1); 225 return (-1); 226 } 227 228 static int 229 fdisused(struct filedesc *fdp, int fd) 230 { 231 232 KASSERT(fd >= 0 && fd < fdp->fd_nfiles, 233 ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles)); 234 235 return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0); 236 } 237 238 /* 239 * Mark a file descriptor as used. 240 */ 241 static void 242 fdused_init(struct filedesc *fdp, int fd) 243 { 244 245 KASSERT(!fdisused(fdp, fd), ("fd=%d is already used", fd)); 246 247 fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd); 248 } 249 250 static void 251 fdused(struct filedesc *fdp, int fd) 252 { 253 254 FILEDESC_XLOCK_ASSERT(fdp); 255 256 fdused_init(fdp, fd); 257 if (fd > fdp->fd_lastfile) 258 fdp->fd_lastfile = fd; 259 if (fd == fdp->fd_freefile) 260 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles); 261 } 262 263 /* 264 * Mark a file descriptor as unused. 265 */ 266 static void 267 fdunused(struct filedesc *fdp, int fd) 268 { 269 270 FILEDESC_XLOCK_ASSERT(fdp); 271 272 KASSERT(fdisused(fdp, fd), ("fd=%d is already unused", fd)); 273 KASSERT(fdp->fd_ofiles[fd].fde_file == NULL, 274 ("fd=%d is still in use", fd)); 275 276 fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd); 277 if (fd < fdp->fd_freefile) 278 fdp->fd_freefile = fd; 279 if (fd == fdp->fd_lastfile) 280 fdp->fd_lastfile = fd_last_used(fdp, fd); 281 } 282 283 /* 284 * Free a file descriptor. 285 * 286 * Avoid some work if fdp is about to be destroyed. 287 */ 288 static inline void 289 fdefree_last(struct filedescent *fde) 290 { 291 292 filecaps_free(&fde->fde_caps); 293 } 294 295 static inline void 296 fdfree(struct filedesc *fdp, int fd) 297 { 298 struct filedescent *fde; 299 300 fde = &fdp->fd_ofiles[fd]; 301 #ifdef CAPABILITIES 302 seq_write_begin(&fde->fde_seq); 303 #endif 304 fdefree_last(fde); 305 fde->fde_file = NULL; 306 fdunused(fdp, fd); 307 #ifdef CAPABILITIES 308 seq_write_end(&fde->fde_seq); 309 #endif 310 } 311 312 void 313 pwd_ensure_dirs(void) 314 { 315 struct filedesc *fdp; 316 317 fdp = curproc->p_fd; 318 FILEDESC_XLOCK(fdp); 319 if (fdp->fd_cdir == NULL) { 320 fdp->fd_cdir = rootvnode; 321 VREF(rootvnode); 322 } 323 if (fdp->fd_rdir == NULL) { 324 fdp->fd_rdir = rootvnode; 325 VREF(rootvnode); 326 } 327 FILEDESC_XUNLOCK(fdp); 328 } 329 330 /* 331 * System calls on descriptors. 332 */ 333 #ifndef _SYS_SYSPROTO_H_ 334 struct getdtablesize_args { 335 int dummy; 336 }; 337 #endif 338 /* ARGSUSED */ 339 int 340 sys_getdtablesize(struct thread *td, struct getdtablesize_args *uap) 341 { 342 #ifdef RACCT 343 uint64_t lim; 344 #endif 345 346 td->td_retval[0] = 347 min((int)lim_cur(td, RLIMIT_NOFILE), maxfilesperproc); 348 #ifdef RACCT 349 PROC_LOCK(td->td_proc); 350 lim = racct_get_limit(td->td_proc, RACCT_NOFILE); 351 PROC_UNLOCK(td->td_proc); 352 if (lim < td->td_retval[0]) 353 td->td_retval[0] = lim; 354 #endif 355 return (0); 356 } 357 358 /* 359 * Duplicate a file descriptor to a particular value. 360 * 361 * Note: keep in mind that a potential race condition exists when closing 362 * descriptors from a shared descriptor table (via rfork). 363 */ 364 #ifndef _SYS_SYSPROTO_H_ 365 struct dup2_args { 366 u_int from; 367 u_int to; 368 }; 369 #endif 370 /* ARGSUSED */ 371 int 372 sys_dup2(struct thread *td, struct dup2_args *uap) 373 { 374 375 return (kern_dup(td, FDDUP_FIXED, 0, (int)uap->from, (int)uap->to)); 376 } 377 378 /* 379 * Duplicate a file descriptor. 380 */ 381 #ifndef _SYS_SYSPROTO_H_ 382 struct dup_args { 383 u_int fd; 384 }; 385 #endif 386 /* ARGSUSED */ 387 int 388 sys_dup(struct thread *td, struct dup_args *uap) 389 { 390 391 return (kern_dup(td, FDDUP_NORMAL, 0, (int)uap->fd, 0)); 392 } 393 394 /* 395 * The file control system call. 396 */ 397 #ifndef _SYS_SYSPROTO_H_ 398 struct fcntl_args { 399 int fd; 400 int cmd; 401 long arg; 402 }; 403 #endif 404 /* ARGSUSED */ 405 int 406 sys_fcntl(struct thread *td, struct fcntl_args *uap) 407 { 408 409 return (kern_fcntl_freebsd(td, uap->fd, uap->cmd, uap->arg)); 410 } 411 412 int 413 kern_fcntl_freebsd(struct thread *td, int fd, int cmd, long arg) 414 { 415 struct flock fl; 416 struct __oflock ofl; 417 intptr_t arg1; 418 int error, newcmd; 419 420 error = 0; 421 newcmd = cmd; 422 switch (cmd) { 423 case F_OGETLK: 424 case F_OSETLK: 425 case F_OSETLKW: 426 /* 427 * Convert old flock structure to new. 428 */ 429 error = copyin((void *)(intptr_t)arg, &ofl, sizeof(ofl)); 430 fl.l_start = ofl.l_start; 431 fl.l_len = ofl.l_len; 432 fl.l_pid = ofl.l_pid; 433 fl.l_type = ofl.l_type; 434 fl.l_whence = ofl.l_whence; 435 fl.l_sysid = 0; 436 437 switch (cmd) { 438 case F_OGETLK: 439 newcmd = F_GETLK; 440 break; 441 case F_OSETLK: 442 newcmd = F_SETLK; 443 break; 444 case F_OSETLKW: 445 newcmd = F_SETLKW; 446 break; 447 } 448 arg1 = (intptr_t)&fl; 449 break; 450 case F_GETLK: 451 case F_SETLK: 452 case F_SETLKW: 453 case F_SETLK_REMOTE: 454 error = copyin((void *)(intptr_t)arg, &fl, sizeof(fl)); 455 arg1 = (intptr_t)&fl; 456 break; 457 default: 458 arg1 = arg; 459 break; 460 } 461 if (error) 462 return (error); 463 error = kern_fcntl(td, fd, newcmd, arg1); 464 if (error) 465 return (error); 466 if (cmd == F_OGETLK) { 467 ofl.l_start = fl.l_start; 468 ofl.l_len = fl.l_len; 469 ofl.l_pid = fl.l_pid; 470 ofl.l_type = fl.l_type; 471 ofl.l_whence = fl.l_whence; 472 error = copyout(&ofl, (void *)(intptr_t)arg, sizeof(ofl)); 473 } else if (cmd == F_GETLK) { 474 error = copyout(&fl, (void *)(intptr_t)arg, sizeof(fl)); 475 } 476 return (error); 477 } 478 479 int 480 kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) 481 { 482 struct filedesc *fdp; 483 struct flock *flp; 484 struct file *fp, *fp2; 485 struct filedescent *fde; 486 struct proc *p; 487 struct vnode *vp; 488 cap_rights_t rights; 489 int error, flg, tmp; 490 uint64_t bsize; 491 off_t foffset; 492 493 error = 0; 494 flg = F_POSIX; 495 p = td->td_proc; 496 fdp = p->p_fd; 497 498 switch (cmd) { 499 case F_DUPFD: 500 tmp = arg; 501 error = kern_dup(td, FDDUP_FCNTL, 0, fd, tmp); 502 break; 503 504 case F_DUPFD_CLOEXEC: 505 tmp = arg; 506 error = kern_dup(td, FDDUP_FCNTL, FDDUP_FLAG_CLOEXEC, fd, tmp); 507 break; 508 509 case F_DUP2FD: 510 tmp = arg; 511 error = kern_dup(td, FDDUP_FIXED, 0, fd, tmp); 512 break; 513 514 case F_DUP2FD_CLOEXEC: 515 tmp = arg; 516 error = kern_dup(td, FDDUP_FIXED, FDDUP_FLAG_CLOEXEC, fd, tmp); 517 break; 518 519 case F_GETFD: 520 error = EBADF; 521 FILEDESC_SLOCK(fdp); 522 fde = fdeget_locked(fdp, fd); 523 if (fde != NULL) { 524 td->td_retval[0] = 525 (fde->fde_flags & UF_EXCLOSE) ? FD_CLOEXEC : 0; 526 error = 0; 527 } 528 FILEDESC_SUNLOCK(fdp); 529 break; 530 531 case F_SETFD: 532 error = EBADF; 533 FILEDESC_XLOCK(fdp); 534 fde = fdeget_locked(fdp, fd); 535 if (fde != NULL) { 536 fde->fde_flags = (fde->fde_flags & ~UF_EXCLOSE) | 537 (arg & FD_CLOEXEC ? UF_EXCLOSE : 0); 538 error = 0; 539 } 540 FILEDESC_XUNLOCK(fdp); 541 break; 542 543 case F_GETFL: 544 error = fget_fcntl(td, fd, 545 cap_rights_init(&rights, CAP_FCNTL), F_GETFL, &fp); 546 if (error != 0) 547 break; 548 td->td_retval[0] = OFLAGS(fp->f_flag); 549 fdrop(fp, td); 550 break; 551 552 case F_SETFL: 553 error = fget_fcntl(td, fd, 554 cap_rights_init(&rights, CAP_FCNTL), F_SETFL, &fp); 555 if (error != 0) 556 break; 557 do { 558 tmp = flg = fp->f_flag; 559 tmp &= ~FCNTLFLAGS; 560 tmp |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS; 561 } while(atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0); 562 tmp = fp->f_flag & FNONBLOCK; 563 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 564 if (error != 0) { 565 fdrop(fp, td); 566 break; 567 } 568 tmp = fp->f_flag & FASYNC; 569 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); 570 if (error == 0) { 571 fdrop(fp, td); 572 break; 573 } 574 atomic_clear_int(&fp->f_flag, FNONBLOCK); 575 tmp = 0; 576 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); 577 fdrop(fp, td); 578 break; 579 580 case F_GETOWN: 581 error = fget_fcntl(td, fd, 582 cap_rights_init(&rights, CAP_FCNTL), F_GETOWN, &fp); 583 if (error != 0) 584 break; 585 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td); 586 if (error == 0) 587 td->td_retval[0] = tmp; 588 fdrop(fp, td); 589 break; 590 591 case F_SETOWN: 592 error = fget_fcntl(td, fd, 593 cap_rights_init(&rights, CAP_FCNTL), F_SETOWN, &fp); 594 if (error != 0) 595 break; 596 tmp = arg; 597 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td); 598 fdrop(fp, td); 599 break; 600 601 case F_SETLK_REMOTE: 602 error = priv_check(td, PRIV_NFS_LOCKD); 603 if (error) 604 return (error); 605 flg = F_REMOTE; 606 goto do_setlk; 607 608 case F_SETLKW: 609 flg |= F_WAIT; 610 /* FALLTHROUGH F_SETLK */ 611 612 case F_SETLK: 613 do_setlk: 614 cap_rights_init(&rights, CAP_FLOCK); 615 error = fget_unlocked(fdp, fd, &rights, &fp, NULL); 616 if (error != 0) 617 break; 618 if (fp->f_type != DTYPE_VNODE) { 619 error = EBADF; 620 fdrop(fp, td); 621 break; 622 } 623 624 flp = (struct flock *)arg; 625 if (flp->l_whence == SEEK_CUR) { 626 foffset = foffset_get(fp); 627 if (foffset < 0 || 628 (flp->l_start > 0 && 629 foffset > OFF_MAX - flp->l_start)) { 630 error = EOVERFLOW; 631 fdrop(fp, td); 632 break; 633 } 634 flp->l_start += foffset; 635 } 636 637 vp = fp->f_vnode; 638 switch (flp->l_type) { 639 case F_RDLCK: 640 if ((fp->f_flag & FREAD) == 0) { 641 error = EBADF; 642 break; 643 } 644 PROC_LOCK(p->p_leader); 645 p->p_leader->p_flag |= P_ADVLOCK; 646 PROC_UNLOCK(p->p_leader); 647 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 648 flp, flg); 649 break; 650 case F_WRLCK: 651 if ((fp->f_flag & FWRITE) == 0) { 652 error = EBADF; 653 break; 654 } 655 PROC_LOCK(p->p_leader); 656 p->p_leader->p_flag |= P_ADVLOCK; 657 PROC_UNLOCK(p->p_leader); 658 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 659 flp, flg); 660 break; 661 case F_UNLCK: 662 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 663 flp, flg); 664 break; 665 case F_UNLCKSYS: 666 /* 667 * Temporary api for testing remote lock 668 * infrastructure. 669 */ 670 if (flg != F_REMOTE) { 671 error = EINVAL; 672 break; 673 } 674 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 675 F_UNLCKSYS, flp, flg); 676 break; 677 default: 678 error = EINVAL; 679 break; 680 } 681 if (error != 0 || flp->l_type == F_UNLCK || 682 flp->l_type == F_UNLCKSYS) { 683 fdrop(fp, td); 684 break; 685 } 686 687 /* 688 * Check for a race with close. 689 * 690 * The vnode is now advisory locked (or unlocked, but this case 691 * is not really important) as the caller requested. 692 * We had to drop the filedesc lock, so we need to recheck if 693 * the descriptor is still valid, because if it was closed 694 * in the meantime we need to remove advisory lock from the 695 * vnode - close on any descriptor leading to an advisory 696 * locked vnode, removes that lock. 697 * We will return 0 on purpose in that case, as the result of 698 * successful advisory lock might have been externally visible 699 * already. This is fine - effectively we pretend to the caller 700 * that the closing thread was a bit slower and that the 701 * advisory lock succeeded before the close. 702 */ 703 error = fget_unlocked(fdp, fd, &rights, &fp2, NULL); 704 if (error != 0) { 705 fdrop(fp, td); 706 break; 707 } 708 if (fp != fp2) { 709 flp->l_whence = SEEK_SET; 710 flp->l_start = 0; 711 flp->l_len = 0; 712 flp->l_type = F_UNLCK; 713 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 714 F_UNLCK, flp, F_POSIX); 715 } 716 fdrop(fp, td); 717 fdrop(fp2, td); 718 break; 719 720 case F_GETLK: 721 error = fget_unlocked(fdp, fd, 722 cap_rights_init(&rights, CAP_FLOCK), &fp, NULL); 723 if (error != 0) 724 break; 725 if (fp->f_type != DTYPE_VNODE) { 726 error = EBADF; 727 fdrop(fp, td); 728 break; 729 } 730 flp = (struct flock *)arg; 731 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK && 732 flp->l_type != F_UNLCK) { 733 error = EINVAL; 734 fdrop(fp, td); 735 break; 736 } 737 if (flp->l_whence == SEEK_CUR) { 738 foffset = foffset_get(fp); 739 if ((flp->l_start > 0 && 740 foffset > OFF_MAX - flp->l_start) || 741 (flp->l_start < 0 && 742 foffset < OFF_MIN - flp->l_start)) { 743 error = EOVERFLOW; 744 fdrop(fp, td); 745 break; 746 } 747 flp->l_start += foffset; 748 } 749 vp = fp->f_vnode; 750 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp, 751 F_POSIX); 752 fdrop(fp, td); 753 break; 754 755 case F_RDAHEAD: 756 arg = arg ? 128 * 1024: 0; 757 /* FALLTHROUGH */ 758 case F_READAHEAD: 759 error = fget_unlocked(fdp, fd, 760 cap_rights_init(&rights), &fp, NULL); 761 if (error != 0) 762 break; 763 if (fp->f_type != DTYPE_VNODE) { 764 fdrop(fp, td); 765 error = EBADF; 766 break; 767 } 768 vp = fp->f_vnode; 769 /* 770 * Exclusive lock synchronizes against f_seqcount reads and 771 * writes in sequential_heuristic(). 772 */ 773 error = vn_lock(vp, LK_EXCLUSIVE); 774 if (error != 0) { 775 fdrop(fp, td); 776 break; 777 } 778 if (arg >= 0) { 779 bsize = fp->f_vnode->v_mount->mnt_stat.f_iosize; 780 fp->f_seqcount = (arg + bsize - 1) / bsize; 781 atomic_set_int(&fp->f_flag, FRDAHEAD); 782 } else { 783 atomic_clear_int(&fp->f_flag, FRDAHEAD); 784 } 785 VOP_UNLOCK(vp, 0); 786 fdrop(fp, td); 787 break; 788 789 default: 790 error = EINVAL; 791 break; 792 } 793 return (error); 794 } 795 796 static int 797 getmaxfd(struct thread *td) 798 { 799 800 return (min((int)lim_cur(td, RLIMIT_NOFILE), maxfilesperproc)); 801 } 802 803 /* 804 * Common code for dup, dup2, fcntl(F_DUPFD) and fcntl(F_DUP2FD). 805 */ 806 int 807 kern_dup(struct thread *td, u_int mode, int flags, int old, int new) 808 { 809 struct filedesc *fdp; 810 struct filedescent *oldfde, *newfde; 811 struct proc *p; 812 struct file *delfp; 813 int error, maxfd; 814 815 p = td->td_proc; 816 fdp = p->p_fd; 817 818 MPASS((flags & ~(FDDUP_FLAG_CLOEXEC)) == 0); 819 MPASS(mode < FDDUP_LASTMODE); 820 821 AUDIT_ARG_FD(old); 822 /* XXXRW: if (flags & FDDUP_FIXED) AUDIT_ARG_FD2(new); */ 823 824 /* 825 * Verify we have a valid descriptor to dup from and possibly to 826 * dup to. Unlike dup() and dup2(), fcntl()'s F_DUPFD should 827 * return EINVAL when the new descriptor is out of bounds. 828 */ 829 if (old < 0) 830 return (EBADF); 831 if (new < 0) 832 return (mode == FDDUP_FCNTL ? EINVAL : EBADF); 833 maxfd = getmaxfd(td); 834 if (new >= maxfd) 835 return (mode == FDDUP_FCNTL ? EINVAL : EBADF); 836 837 error = EBADF; 838 FILEDESC_XLOCK(fdp); 839 if (fget_locked(fdp, old) == NULL) 840 goto unlock; 841 if ((mode == FDDUP_FIXED || mode == FDDUP_MUSTREPLACE) && old == new) { 842 td->td_retval[0] = new; 843 if (flags & FDDUP_FLAG_CLOEXEC) 844 fdp->fd_ofiles[new].fde_flags |= UF_EXCLOSE; 845 error = 0; 846 goto unlock; 847 } 848 849 /* 850 * If the caller specified a file descriptor, make sure the file 851 * table is large enough to hold it, and grab it. Otherwise, just 852 * allocate a new descriptor the usual way. 853 */ 854 switch (mode) { 855 case FDDUP_NORMAL: 856 case FDDUP_FCNTL: 857 if ((error = fdalloc(td, new, &new)) != 0) 858 goto unlock; 859 break; 860 case FDDUP_MUSTREPLACE: 861 /* Target file descriptor must exist. */ 862 if (fget_locked(fdp, new) == NULL) 863 goto unlock; 864 break; 865 case FDDUP_FIXED: 866 if (new >= fdp->fd_nfiles) { 867 /* 868 * The resource limits are here instead of e.g. 869 * fdalloc(), because the file descriptor table may be 870 * shared between processes, so we can't really use 871 * racct_add()/racct_sub(). Instead of counting the 872 * number of actually allocated descriptors, just put 873 * the limit on the size of the file descriptor table. 874 */ 875 #ifdef RACCT 876 if (racct_enable) { 877 PROC_LOCK(p); 878 error = racct_set(p, RACCT_NOFILE, new + 1); 879 PROC_UNLOCK(p); 880 if (error != 0) { 881 error = EMFILE; 882 goto unlock; 883 } 884 } 885 #endif 886 fdgrowtable_exp(fdp, new + 1); 887 } 888 if (!fdisused(fdp, new)) 889 fdused(fdp, new); 890 break; 891 default: 892 KASSERT(0, ("%s unsupported mode %d", __func__, mode)); 893 } 894 895 KASSERT(old != new, ("new fd is same as old")); 896 897 oldfde = &fdp->fd_ofiles[old]; 898 fhold(oldfde->fde_file); 899 newfde = &fdp->fd_ofiles[new]; 900 delfp = newfde->fde_file; 901 902 /* 903 * Duplicate the source descriptor. 904 */ 905 #ifdef CAPABILITIES 906 seq_write_begin(&newfde->fde_seq); 907 #endif 908 filecaps_free(&newfde->fde_caps); 909 memcpy(newfde, oldfde, fde_change_size); 910 filecaps_copy(&oldfde->fde_caps, &newfde->fde_caps, true); 911 if ((flags & FDDUP_FLAG_CLOEXEC) != 0) 912 newfde->fde_flags = oldfde->fde_flags | UF_EXCLOSE; 913 else 914 newfde->fde_flags = oldfde->fde_flags & ~UF_EXCLOSE; 915 #ifdef CAPABILITIES 916 seq_write_end(&newfde->fde_seq); 917 #endif 918 td->td_retval[0] = new; 919 920 error = 0; 921 922 if (delfp != NULL) { 923 (void) closefp(fdp, new, delfp, td, 1); 924 FILEDESC_UNLOCK_ASSERT(fdp); 925 } else { 926 unlock: 927 FILEDESC_XUNLOCK(fdp); 928 } 929 930 return (error); 931 } 932 933 /* 934 * If sigio is on the list associated with a process or process group, 935 * disable signalling from the device, remove sigio from the list and 936 * free sigio. 937 */ 938 void 939 funsetown(struct sigio **sigiop) 940 { 941 struct sigio *sigio; 942 943 if (*sigiop == NULL) 944 return; 945 SIGIO_LOCK(); 946 sigio = *sigiop; 947 if (sigio == NULL) { 948 SIGIO_UNLOCK(); 949 return; 950 } 951 *(sigio->sio_myref) = NULL; 952 if ((sigio)->sio_pgid < 0) { 953 struct pgrp *pg = (sigio)->sio_pgrp; 954 PGRP_LOCK(pg); 955 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio, 956 sigio, sio_pgsigio); 957 PGRP_UNLOCK(pg); 958 } else { 959 struct proc *p = (sigio)->sio_proc; 960 PROC_LOCK(p); 961 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio, 962 sigio, sio_pgsigio); 963 PROC_UNLOCK(p); 964 } 965 SIGIO_UNLOCK(); 966 crfree(sigio->sio_ucred); 967 free(sigio, M_SIGIO); 968 } 969 970 /* 971 * Free a list of sigio structures. 972 * We only need to lock the SIGIO_LOCK because we have made ourselves 973 * inaccessible to callers of fsetown and therefore do not need to lock 974 * the proc or pgrp struct for the list manipulation. 975 */ 976 void 977 funsetownlst(struct sigiolst *sigiolst) 978 { 979 struct proc *p; 980 struct pgrp *pg; 981 struct sigio *sigio; 982 983 sigio = SLIST_FIRST(sigiolst); 984 if (sigio == NULL) 985 return; 986 p = NULL; 987 pg = NULL; 988 989 /* 990 * Every entry of the list should belong 991 * to a single proc or pgrp. 992 */ 993 if (sigio->sio_pgid < 0) { 994 pg = sigio->sio_pgrp; 995 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED); 996 } else /* if (sigio->sio_pgid > 0) */ { 997 p = sigio->sio_proc; 998 PROC_LOCK_ASSERT(p, MA_NOTOWNED); 999 } 1000 1001 SIGIO_LOCK(); 1002 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) { 1003 *(sigio->sio_myref) = NULL; 1004 if (pg != NULL) { 1005 KASSERT(sigio->sio_pgid < 0, 1006 ("Proc sigio in pgrp sigio list")); 1007 KASSERT(sigio->sio_pgrp == pg, 1008 ("Bogus pgrp in sigio list")); 1009 PGRP_LOCK(pg); 1010 SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio, 1011 sio_pgsigio); 1012 PGRP_UNLOCK(pg); 1013 } else /* if (p != NULL) */ { 1014 KASSERT(sigio->sio_pgid > 0, 1015 ("Pgrp sigio in proc sigio list")); 1016 KASSERT(sigio->sio_proc == p, 1017 ("Bogus proc in sigio list")); 1018 PROC_LOCK(p); 1019 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, 1020 sio_pgsigio); 1021 PROC_UNLOCK(p); 1022 } 1023 SIGIO_UNLOCK(); 1024 crfree(sigio->sio_ucred); 1025 free(sigio, M_SIGIO); 1026 SIGIO_LOCK(); 1027 } 1028 SIGIO_UNLOCK(); 1029 } 1030 1031 /* 1032 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 1033 * 1034 * After permission checking, add a sigio structure to the sigio list for 1035 * the process or process group. 1036 */ 1037 int 1038 fsetown(pid_t pgid, struct sigio **sigiop) 1039 { 1040 struct proc *proc; 1041 struct pgrp *pgrp; 1042 struct sigio *sigio; 1043 int ret; 1044 1045 if (pgid == 0) { 1046 funsetown(sigiop); 1047 return (0); 1048 } 1049 1050 ret = 0; 1051 1052 /* Allocate and fill in the new sigio out of locks. */ 1053 sigio = malloc(sizeof(struct sigio), M_SIGIO, M_WAITOK); 1054 sigio->sio_pgid = pgid; 1055 sigio->sio_ucred = crhold(curthread->td_ucred); 1056 sigio->sio_myref = sigiop; 1057 1058 sx_slock(&proctree_lock); 1059 if (pgid > 0) { 1060 proc = pfind(pgid); 1061 if (proc == NULL) { 1062 ret = ESRCH; 1063 goto fail; 1064 } 1065 1066 /* 1067 * Policy - Don't allow a process to FSETOWN a process 1068 * in another session. 1069 * 1070 * Remove this test to allow maximum flexibility or 1071 * restrict FSETOWN to the current process or process 1072 * group for maximum safety. 1073 */ 1074 PROC_UNLOCK(proc); 1075 if (proc->p_session != curthread->td_proc->p_session) { 1076 ret = EPERM; 1077 goto fail; 1078 } 1079 1080 pgrp = NULL; 1081 } else /* if (pgid < 0) */ { 1082 pgrp = pgfind(-pgid); 1083 if (pgrp == NULL) { 1084 ret = ESRCH; 1085 goto fail; 1086 } 1087 PGRP_UNLOCK(pgrp); 1088 1089 /* 1090 * Policy - Don't allow a process to FSETOWN a process 1091 * in another session. 1092 * 1093 * Remove this test to allow maximum flexibility or 1094 * restrict FSETOWN to the current process or process 1095 * group for maximum safety. 1096 */ 1097 if (pgrp->pg_session != curthread->td_proc->p_session) { 1098 ret = EPERM; 1099 goto fail; 1100 } 1101 1102 proc = NULL; 1103 } 1104 funsetown(sigiop); 1105 if (pgid > 0) { 1106 PROC_LOCK(proc); 1107 /* 1108 * Since funsetownlst() is called without the proctree 1109 * locked, we need to check for P_WEXIT. 1110 * XXX: is ESRCH correct? 1111 */ 1112 if ((proc->p_flag & P_WEXIT) != 0) { 1113 PROC_UNLOCK(proc); 1114 ret = ESRCH; 1115 goto fail; 1116 } 1117 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 1118 sigio->sio_proc = proc; 1119 PROC_UNLOCK(proc); 1120 } else { 1121 PGRP_LOCK(pgrp); 1122 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 1123 sigio->sio_pgrp = pgrp; 1124 PGRP_UNLOCK(pgrp); 1125 } 1126 sx_sunlock(&proctree_lock); 1127 SIGIO_LOCK(); 1128 *sigiop = sigio; 1129 SIGIO_UNLOCK(); 1130 return (0); 1131 1132 fail: 1133 sx_sunlock(&proctree_lock); 1134 crfree(sigio->sio_ucred); 1135 free(sigio, M_SIGIO); 1136 return (ret); 1137 } 1138 1139 /* 1140 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 1141 */ 1142 pid_t 1143 fgetown(sigiop) 1144 struct sigio **sigiop; 1145 { 1146 pid_t pgid; 1147 1148 SIGIO_LOCK(); 1149 pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0; 1150 SIGIO_UNLOCK(); 1151 return (pgid); 1152 } 1153 1154 /* 1155 * Function drops the filedesc lock on return. 1156 */ 1157 static int 1158 closefp(struct filedesc *fdp, int fd, struct file *fp, struct thread *td, 1159 int holdleaders) 1160 { 1161 int error; 1162 1163 FILEDESC_XLOCK_ASSERT(fdp); 1164 1165 if (holdleaders) { 1166 if (td->td_proc->p_fdtol != NULL) { 1167 /* 1168 * Ask fdfree() to sleep to ensure that all relevant 1169 * process leaders can be traversed in closef(). 1170 */ 1171 fdp->fd_holdleaderscount++; 1172 } else { 1173 holdleaders = 0; 1174 } 1175 } 1176 1177 /* 1178 * We now hold the fp reference that used to be owned by the 1179 * descriptor array. We have to unlock the FILEDESC *AFTER* 1180 * knote_fdclose to prevent a race of the fd getting opened, a knote 1181 * added, and deleteing a knote for the new fd. 1182 */ 1183 knote_fdclose(td, fd); 1184 1185 /* 1186 * We need to notify mqueue if the object is of type mqueue. 1187 */ 1188 if (fp->f_type == DTYPE_MQUEUE) 1189 mq_fdclose(td, fd, fp); 1190 FILEDESC_XUNLOCK(fdp); 1191 1192 error = closef(fp, td); 1193 if (holdleaders) { 1194 FILEDESC_XLOCK(fdp); 1195 fdp->fd_holdleaderscount--; 1196 if (fdp->fd_holdleaderscount == 0 && 1197 fdp->fd_holdleaderswakeup != 0) { 1198 fdp->fd_holdleaderswakeup = 0; 1199 wakeup(&fdp->fd_holdleaderscount); 1200 } 1201 FILEDESC_XUNLOCK(fdp); 1202 } 1203 return (error); 1204 } 1205 1206 /* 1207 * Close a file descriptor. 1208 */ 1209 #ifndef _SYS_SYSPROTO_H_ 1210 struct close_args { 1211 int fd; 1212 }; 1213 #endif 1214 /* ARGSUSED */ 1215 int 1216 sys_close(struct thread *td, struct close_args *uap) 1217 { 1218 1219 return (kern_close(td, uap->fd)); 1220 } 1221 1222 int 1223 kern_close(struct thread *td, int fd) 1224 { 1225 struct filedesc *fdp; 1226 struct file *fp; 1227 1228 fdp = td->td_proc->p_fd; 1229 1230 AUDIT_SYSCLOSE(td, fd); 1231 1232 FILEDESC_XLOCK(fdp); 1233 if ((fp = fget_locked(fdp, fd)) == NULL) { 1234 FILEDESC_XUNLOCK(fdp); 1235 return (EBADF); 1236 } 1237 fdfree(fdp, fd); 1238 1239 /* closefp() drops the FILEDESC lock for us. */ 1240 return (closefp(fdp, fd, fp, td, 1)); 1241 } 1242 1243 /* 1244 * Close open file descriptors. 1245 */ 1246 #ifndef _SYS_SYSPROTO_H_ 1247 struct closefrom_args { 1248 int lowfd; 1249 }; 1250 #endif 1251 /* ARGSUSED */ 1252 int 1253 sys_closefrom(struct thread *td, struct closefrom_args *uap) 1254 { 1255 struct filedesc *fdp; 1256 int fd; 1257 1258 fdp = td->td_proc->p_fd; 1259 AUDIT_ARG_FD(uap->lowfd); 1260 1261 /* 1262 * Treat negative starting file descriptor values identical to 1263 * closefrom(0) which closes all files. 1264 */ 1265 if (uap->lowfd < 0) 1266 uap->lowfd = 0; 1267 FILEDESC_SLOCK(fdp); 1268 for (fd = uap->lowfd; fd <= fdp->fd_lastfile; fd++) { 1269 if (fdp->fd_ofiles[fd].fde_file != NULL) { 1270 FILEDESC_SUNLOCK(fdp); 1271 (void)kern_close(td, fd); 1272 FILEDESC_SLOCK(fdp); 1273 } 1274 } 1275 FILEDESC_SUNLOCK(fdp); 1276 return (0); 1277 } 1278 1279 #if defined(COMPAT_43) 1280 /* 1281 * Return status information about a file descriptor. 1282 */ 1283 #ifndef _SYS_SYSPROTO_H_ 1284 struct ofstat_args { 1285 int fd; 1286 struct ostat *sb; 1287 }; 1288 #endif 1289 /* ARGSUSED */ 1290 int 1291 ofstat(struct thread *td, struct ofstat_args *uap) 1292 { 1293 struct ostat oub; 1294 struct stat ub; 1295 int error; 1296 1297 error = kern_fstat(td, uap->fd, &ub); 1298 if (error == 0) { 1299 cvtstat(&ub, &oub); 1300 error = copyout(&oub, uap->sb, sizeof(oub)); 1301 } 1302 return (error); 1303 } 1304 #endif /* COMPAT_43 */ 1305 1306 /* 1307 * Return status information about a file descriptor. 1308 */ 1309 #ifndef _SYS_SYSPROTO_H_ 1310 struct fstat_args { 1311 int fd; 1312 struct stat *sb; 1313 }; 1314 #endif 1315 /* ARGSUSED */ 1316 int 1317 sys_fstat(struct thread *td, struct fstat_args *uap) 1318 { 1319 struct stat ub; 1320 int error; 1321 1322 error = kern_fstat(td, uap->fd, &ub); 1323 if (error == 0) 1324 error = copyout(&ub, uap->sb, sizeof(ub)); 1325 return (error); 1326 } 1327 1328 int 1329 kern_fstat(struct thread *td, int fd, struct stat *sbp) 1330 { 1331 struct file *fp; 1332 cap_rights_t rights; 1333 int error; 1334 1335 AUDIT_ARG_FD(fd); 1336 1337 error = fget(td, fd, cap_rights_init(&rights, CAP_FSTAT), &fp); 1338 if (error != 0) 1339 return (error); 1340 1341 AUDIT_ARG_FILE(td->td_proc, fp); 1342 1343 error = fo_stat(fp, sbp, td->td_ucred, td); 1344 fdrop(fp, td); 1345 #ifdef KTRACE 1346 if (error == 0 && KTRPOINT(td, KTR_STRUCT)) 1347 ktrstat(sbp); 1348 #endif 1349 return (error); 1350 } 1351 1352 /* 1353 * Return status information about a file descriptor. 1354 */ 1355 #ifndef _SYS_SYSPROTO_H_ 1356 struct nfstat_args { 1357 int fd; 1358 struct nstat *sb; 1359 }; 1360 #endif 1361 /* ARGSUSED */ 1362 int 1363 sys_nfstat(struct thread *td, struct nfstat_args *uap) 1364 { 1365 struct nstat nub; 1366 struct stat ub; 1367 int error; 1368 1369 error = kern_fstat(td, uap->fd, &ub); 1370 if (error == 0) { 1371 cvtnstat(&ub, &nub); 1372 error = copyout(&nub, uap->sb, sizeof(nub)); 1373 } 1374 return (error); 1375 } 1376 1377 /* 1378 * Return pathconf information about a file descriptor. 1379 */ 1380 #ifndef _SYS_SYSPROTO_H_ 1381 struct fpathconf_args { 1382 int fd; 1383 int name; 1384 }; 1385 #endif 1386 /* ARGSUSED */ 1387 int 1388 sys_fpathconf(struct thread *td, struct fpathconf_args *uap) 1389 { 1390 struct file *fp; 1391 struct vnode *vp; 1392 cap_rights_t rights; 1393 int error; 1394 1395 error = fget(td, uap->fd, cap_rights_init(&rights, CAP_FPATHCONF), &fp); 1396 if (error != 0) 1397 return (error); 1398 1399 if (uap->name == _PC_ASYNC_IO) { 1400 td->td_retval[0] = _POSIX_ASYNCHRONOUS_IO; 1401 goto out; 1402 } 1403 vp = fp->f_vnode; 1404 if (vp != NULL) { 1405 vn_lock(vp, LK_SHARED | LK_RETRY); 1406 error = VOP_PATHCONF(vp, uap->name, td->td_retval); 1407 VOP_UNLOCK(vp, 0); 1408 } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) { 1409 if (uap->name != _PC_PIPE_BUF) { 1410 error = EINVAL; 1411 } else { 1412 td->td_retval[0] = PIPE_BUF; 1413 error = 0; 1414 } 1415 } else { 1416 error = EOPNOTSUPP; 1417 } 1418 out: 1419 fdrop(fp, td); 1420 return (error); 1421 } 1422 1423 /* 1424 * Initialize filecaps structure. 1425 */ 1426 void 1427 filecaps_init(struct filecaps *fcaps) 1428 { 1429 1430 bzero(fcaps, sizeof(*fcaps)); 1431 fcaps->fc_nioctls = -1; 1432 } 1433 1434 /* 1435 * Copy filecaps structure allocating memory for ioctls array if needed. 1436 * 1437 * The last parameter indicates whether the fdtable is locked. If it is not and 1438 * ioctls are encountered, copying fails and the caller must lock the table. 1439 * 1440 * Note that if the table was not locked, the caller has to check the relevant 1441 * sequence counter to determine whether the operation was successful. 1442 */ 1443 int 1444 filecaps_copy(const struct filecaps *src, struct filecaps *dst, bool locked) 1445 { 1446 size_t size; 1447 1448 *dst = *src; 1449 if (src->fc_ioctls == NULL) 1450 return (0); 1451 if (!locked) 1452 return (1); 1453 1454 KASSERT(src->fc_nioctls > 0, 1455 ("fc_ioctls != NULL, but fc_nioctls=%hd", src->fc_nioctls)); 1456 1457 size = sizeof(src->fc_ioctls[0]) * src->fc_nioctls; 1458 dst->fc_ioctls = malloc(size, M_FILECAPS, M_WAITOK); 1459 bcopy(src->fc_ioctls, dst->fc_ioctls, size); 1460 return (0); 1461 } 1462 1463 /* 1464 * Move filecaps structure to the new place and clear the old place. 1465 */ 1466 void 1467 filecaps_move(struct filecaps *src, struct filecaps *dst) 1468 { 1469 1470 *dst = *src; 1471 bzero(src, sizeof(*src)); 1472 } 1473 1474 /* 1475 * Fill the given filecaps structure with full rights. 1476 */ 1477 static void 1478 filecaps_fill(struct filecaps *fcaps) 1479 { 1480 1481 CAP_ALL(&fcaps->fc_rights); 1482 fcaps->fc_ioctls = NULL; 1483 fcaps->fc_nioctls = -1; 1484 fcaps->fc_fcntls = CAP_FCNTL_ALL; 1485 } 1486 1487 /* 1488 * Free memory allocated within filecaps structure. 1489 */ 1490 void 1491 filecaps_free(struct filecaps *fcaps) 1492 { 1493 1494 free(fcaps->fc_ioctls, M_FILECAPS); 1495 bzero(fcaps, sizeof(*fcaps)); 1496 } 1497 1498 /* 1499 * Validate the given filecaps structure. 1500 */ 1501 static void 1502 filecaps_validate(const struct filecaps *fcaps, const char *func) 1503 { 1504 1505 KASSERT(cap_rights_is_valid(&fcaps->fc_rights), 1506 ("%s: invalid rights", func)); 1507 KASSERT((fcaps->fc_fcntls & ~CAP_FCNTL_ALL) == 0, 1508 ("%s: invalid fcntls", func)); 1509 KASSERT(fcaps->fc_fcntls == 0 || 1510 cap_rights_is_set(&fcaps->fc_rights, CAP_FCNTL), 1511 ("%s: fcntls without CAP_FCNTL", func)); 1512 KASSERT(fcaps->fc_ioctls != NULL ? fcaps->fc_nioctls > 0 : 1513 (fcaps->fc_nioctls == -1 || fcaps->fc_nioctls == 0), 1514 ("%s: invalid ioctls", func)); 1515 KASSERT(fcaps->fc_nioctls == 0 || 1516 cap_rights_is_set(&fcaps->fc_rights, CAP_IOCTL), 1517 ("%s: ioctls without CAP_IOCTL", func)); 1518 } 1519 1520 static void 1521 fdgrowtable_exp(struct filedesc *fdp, int nfd) 1522 { 1523 int nfd1; 1524 1525 FILEDESC_XLOCK_ASSERT(fdp); 1526 1527 nfd1 = fdp->fd_nfiles * 2; 1528 if (nfd1 < nfd) 1529 nfd1 = nfd; 1530 fdgrowtable(fdp, nfd1); 1531 } 1532 1533 /* 1534 * Grow the file table to accommodate (at least) nfd descriptors. 1535 */ 1536 static void 1537 fdgrowtable(struct filedesc *fdp, int nfd) 1538 { 1539 struct filedesc0 *fdp0; 1540 struct freetable *ft; 1541 struct fdescenttbl *ntable; 1542 struct fdescenttbl *otable; 1543 int nnfiles, onfiles; 1544 NDSLOTTYPE *nmap, *omap; 1545 1546 /* 1547 * If lastfile is -1 this struct filedesc was just allocated and we are 1548 * growing it to accommodate for the one we are going to copy from. There 1549 * is no need to have a lock on this one as it's not visible to anyone. 1550 */ 1551 if (fdp->fd_lastfile != -1) 1552 FILEDESC_XLOCK_ASSERT(fdp); 1553 1554 KASSERT(fdp->fd_nfiles > 0, ("zero-length file table")); 1555 1556 /* save old values */ 1557 onfiles = fdp->fd_nfiles; 1558 otable = fdp->fd_files; 1559 omap = fdp->fd_map; 1560 1561 /* compute the size of the new table */ 1562 nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */ 1563 if (nnfiles <= onfiles) 1564 /* the table is already large enough */ 1565 return; 1566 1567 /* 1568 * Allocate a new table. We need enough space for the number of 1569 * entries, file entries themselves and the struct freetable we will use 1570 * when we decommission the table and place it on the freelist. 1571 * We place the struct freetable in the middle so we don't have 1572 * to worry about padding. 1573 */ 1574 ntable = malloc(offsetof(struct fdescenttbl, fdt_ofiles) + 1575 nnfiles * sizeof(ntable->fdt_ofiles[0]) + 1576 sizeof(struct freetable), 1577 M_FILEDESC, M_ZERO | M_WAITOK); 1578 /* copy the old data */ 1579 ntable->fdt_nfiles = nnfiles; 1580 memcpy(ntable->fdt_ofiles, otable->fdt_ofiles, 1581 onfiles * sizeof(ntable->fdt_ofiles[0])); 1582 1583 /* 1584 * Allocate a new map only if the old is not large enough. It will 1585 * grow at a slower rate than the table as it can map more 1586 * entries than the table can hold. 1587 */ 1588 if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) { 1589 nmap = malloc(NDSLOTS(nnfiles) * NDSLOTSIZE, M_FILEDESC, 1590 M_ZERO | M_WAITOK); 1591 /* copy over the old data and update the pointer */ 1592 memcpy(nmap, omap, NDSLOTS(onfiles) * sizeof(*omap)); 1593 fdp->fd_map = nmap; 1594 } 1595 1596 /* 1597 * Make sure that ntable is correctly initialized before we replace 1598 * fd_files poiner. Otherwise fget_unlocked() may see inconsistent 1599 * data. 1600 */ 1601 atomic_store_rel_ptr((volatile void *)&fdp->fd_files, (uintptr_t)ntable); 1602 1603 /* 1604 * Do not free the old file table, as some threads may still 1605 * reference entries within it. Instead, place it on a freelist 1606 * which will be processed when the struct filedesc is released. 1607 * 1608 * Note that if onfiles == NDFILE, we're dealing with the original 1609 * static allocation contained within (struct filedesc0 *)fdp, 1610 * which must not be freed. 1611 */ 1612 if (onfiles > NDFILE) { 1613 ft = (struct freetable *)&otable->fdt_ofiles[onfiles]; 1614 fdp0 = (struct filedesc0 *)fdp; 1615 ft->ft_table = otable; 1616 SLIST_INSERT_HEAD(&fdp0->fd_free, ft, ft_next); 1617 } 1618 /* 1619 * The map does not have the same possibility of threads still 1620 * holding references to it. So always free it as long as it 1621 * does not reference the original static allocation. 1622 */ 1623 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE)) 1624 free(omap, M_FILEDESC); 1625 } 1626 1627 /* 1628 * Allocate a file descriptor for the process. 1629 */ 1630 int 1631 fdalloc(struct thread *td, int minfd, int *result) 1632 { 1633 struct proc *p = td->td_proc; 1634 struct filedesc *fdp = p->p_fd; 1635 int fd, maxfd, allocfd; 1636 #ifdef RACCT 1637 int error; 1638 #endif 1639 1640 FILEDESC_XLOCK_ASSERT(fdp); 1641 1642 if (fdp->fd_freefile > minfd) 1643 minfd = fdp->fd_freefile; 1644 1645 maxfd = getmaxfd(td); 1646 1647 /* 1648 * Search the bitmap for a free descriptor starting at minfd. 1649 * If none is found, grow the file table. 1650 */ 1651 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles); 1652 if (fd >= maxfd) 1653 return (EMFILE); 1654 if (fd >= fdp->fd_nfiles) { 1655 allocfd = min(fd * 2, maxfd); 1656 #ifdef RACCT 1657 if (racct_enable) { 1658 PROC_LOCK(p); 1659 error = racct_set(p, RACCT_NOFILE, allocfd); 1660 PROC_UNLOCK(p); 1661 if (error != 0) 1662 return (EMFILE); 1663 } 1664 #endif 1665 /* 1666 * fd is already equal to first free descriptor >= minfd, so 1667 * we only need to grow the table and we are done. 1668 */ 1669 fdgrowtable_exp(fdp, allocfd); 1670 } 1671 1672 /* 1673 * Perform some sanity checks, then mark the file descriptor as 1674 * used and return it to the caller. 1675 */ 1676 KASSERT(fd >= 0 && fd < min(maxfd, fdp->fd_nfiles), 1677 ("invalid descriptor %d", fd)); 1678 KASSERT(!fdisused(fdp, fd), 1679 ("fd_first_free() returned non-free descriptor")); 1680 KASSERT(fdp->fd_ofiles[fd].fde_file == NULL, 1681 ("file descriptor isn't free")); 1682 fdused(fdp, fd); 1683 *result = fd; 1684 return (0); 1685 } 1686 1687 /* 1688 * Allocate n file descriptors for the process. 1689 */ 1690 int 1691 fdallocn(struct thread *td, int minfd, int *fds, int n) 1692 { 1693 struct proc *p = td->td_proc; 1694 struct filedesc *fdp = p->p_fd; 1695 int i; 1696 1697 FILEDESC_XLOCK_ASSERT(fdp); 1698 1699 for (i = 0; i < n; i++) 1700 if (fdalloc(td, 0, &fds[i]) != 0) 1701 break; 1702 1703 if (i < n) { 1704 for (i--; i >= 0; i--) 1705 fdunused(fdp, fds[i]); 1706 return (EMFILE); 1707 } 1708 1709 return (0); 1710 } 1711 1712 /* 1713 * Create a new open file structure and allocate a file descriptor for the 1714 * process that refers to it. We add one reference to the file for the 1715 * descriptor table and one reference for resultfp. This is to prevent us 1716 * being preempted and the entry in the descriptor table closed after we 1717 * release the FILEDESC lock. 1718 */ 1719 int 1720 falloc_caps(struct thread *td, struct file **resultfp, int *resultfd, int flags, 1721 struct filecaps *fcaps) 1722 { 1723 struct file *fp; 1724 int error, fd; 1725 1726 error = falloc_noinstall(td, &fp); 1727 if (error) 1728 return (error); /* no reference held on error */ 1729 1730 error = finstall(td, fp, &fd, flags, fcaps); 1731 if (error) { 1732 fdrop(fp, td); /* one reference (fp only) */ 1733 return (error); 1734 } 1735 1736 if (resultfp != NULL) 1737 *resultfp = fp; /* copy out result */ 1738 else 1739 fdrop(fp, td); /* release local reference */ 1740 1741 if (resultfd != NULL) 1742 *resultfd = fd; 1743 1744 return (0); 1745 } 1746 1747 /* 1748 * Create a new open file structure without allocating a file descriptor. 1749 */ 1750 int 1751 falloc_noinstall(struct thread *td, struct file **resultfp) 1752 { 1753 struct file *fp; 1754 int maxuserfiles = maxfiles - (maxfiles / 20); 1755 static struct timeval lastfail; 1756 static int curfail; 1757 1758 KASSERT(resultfp != NULL, ("%s: resultfp == NULL", __func__)); 1759 1760 if ((openfiles >= maxuserfiles && 1761 priv_check(td, PRIV_MAXFILES) != 0) || 1762 openfiles >= maxfiles) { 1763 if (ppsratecheck(&lastfail, &curfail, 1)) { 1764 printf("kern.maxfiles limit exceeded by uid %i, " 1765 "please see tuning(7).\n", td->td_ucred->cr_ruid); 1766 } 1767 return (ENFILE); 1768 } 1769 atomic_add_int(&openfiles, 1); 1770 fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO); 1771 refcount_init(&fp->f_count, 1); 1772 fp->f_cred = crhold(td->td_ucred); 1773 fp->f_ops = &badfileops; 1774 *resultfp = fp; 1775 return (0); 1776 } 1777 1778 /* 1779 * Install a file in a file descriptor table. 1780 */ 1781 void 1782 _finstall(struct filedesc *fdp, struct file *fp, int fd, int flags, 1783 struct filecaps *fcaps) 1784 { 1785 struct filedescent *fde; 1786 1787 MPASS(fp != NULL); 1788 if (fcaps != NULL) 1789 filecaps_validate(fcaps, __func__); 1790 FILEDESC_XLOCK_ASSERT(fdp); 1791 1792 fde = &fdp->fd_ofiles[fd]; 1793 #ifdef CAPABILITIES 1794 seq_write_begin(&fde->fde_seq); 1795 #endif 1796 fde->fde_file = fp; 1797 fde->fde_flags = (flags & O_CLOEXEC) != 0 ? UF_EXCLOSE : 0; 1798 if (fcaps != NULL) 1799 filecaps_move(fcaps, &fde->fde_caps); 1800 else 1801 filecaps_fill(&fde->fde_caps); 1802 #ifdef CAPABILITIES 1803 seq_write_end(&fde->fde_seq); 1804 #endif 1805 } 1806 1807 int 1808 finstall(struct thread *td, struct file *fp, int *fd, int flags, 1809 struct filecaps *fcaps) 1810 { 1811 struct filedesc *fdp = td->td_proc->p_fd; 1812 int error; 1813 1814 MPASS(fd != NULL); 1815 1816 FILEDESC_XLOCK(fdp); 1817 if ((error = fdalloc(td, 0, fd))) { 1818 FILEDESC_XUNLOCK(fdp); 1819 return (error); 1820 } 1821 fhold(fp); 1822 _finstall(fdp, fp, *fd, flags, fcaps); 1823 FILEDESC_XUNLOCK(fdp); 1824 return (0); 1825 } 1826 1827 /* 1828 * Build a new filedesc structure from another. 1829 * Copy the current, root, and jail root vnode references. 1830 * 1831 * If fdp is not NULL, return with it shared locked. 1832 */ 1833 struct filedesc * 1834 fdinit(struct filedesc *fdp, bool prepfiles) 1835 { 1836 struct filedesc0 *newfdp0; 1837 struct filedesc *newfdp; 1838 1839 newfdp0 = uma_zalloc(filedesc0_zone, M_WAITOK | M_ZERO); 1840 newfdp = &newfdp0->fd_fd; 1841 1842 /* Create the file descriptor table. */ 1843 FILEDESC_LOCK_INIT(newfdp); 1844 refcount_init(&newfdp->fd_refcnt, 1); 1845 refcount_init(&newfdp->fd_holdcnt, 1); 1846 newfdp->fd_cmask = CMASK; 1847 newfdp->fd_map = newfdp0->fd_dmap; 1848 newfdp->fd_lastfile = -1; 1849 newfdp->fd_files = (struct fdescenttbl *)&newfdp0->fd_dfiles; 1850 newfdp->fd_files->fdt_nfiles = NDFILE; 1851 1852 if (fdp == NULL) 1853 return (newfdp); 1854 1855 if (prepfiles && fdp->fd_lastfile >= newfdp->fd_nfiles) 1856 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1857 1858 FILEDESC_SLOCK(fdp); 1859 newfdp->fd_cdir = fdp->fd_cdir; 1860 if (newfdp->fd_cdir) 1861 VREF(newfdp->fd_cdir); 1862 newfdp->fd_rdir = fdp->fd_rdir; 1863 if (newfdp->fd_rdir) 1864 VREF(newfdp->fd_rdir); 1865 newfdp->fd_jdir = fdp->fd_jdir; 1866 if (newfdp->fd_jdir) 1867 VREF(newfdp->fd_jdir); 1868 1869 if (!prepfiles) { 1870 FILEDESC_SUNLOCK(fdp); 1871 } else { 1872 while (fdp->fd_lastfile >= newfdp->fd_nfiles) { 1873 FILEDESC_SUNLOCK(fdp); 1874 fdgrowtable(newfdp, fdp->fd_lastfile + 1); 1875 FILEDESC_SLOCK(fdp); 1876 } 1877 } 1878 1879 return (newfdp); 1880 } 1881 1882 static struct filedesc * 1883 fdhold(struct proc *p) 1884 { 1885 struct filedesc *fdp; 1886 1887 PROC_LOCK_ASSERT(p, MA_OWNED); 1888 fdp = p->p_fd; 1889 if (fdp != NULL) 1890 refcount_acquire(&fdp->fd_holdcnt); 1891 return (fdp); 1892 } 1893 1894 static void 1895 fddrop(struct filedesc *fdp) 1896 { 1897 1898 if (fdp->fd_holdcnt > 1) { 1899 if (refcount_release(&fdp->fd_holdcnt) == 0) 1900 return; 1901 } 1902 1903 FILEDESC_LOCK_DESTROY(fdp); 1904 uma_zfree(filedesc0_zone, fdp); 1905 } 1906 1907 /* 1908 * Share a filedesc structure. 1909 */ 1910 struct filedesc * 1911 fdshare(struct filedesc *fdp) 1912 { 1913 1914 refcount_acquire(&fdp->fd_refcnt); 1915 return (fdp); 1916 } 1917 1918 /* 1919 * Unshare a filedesc structure, if necessary by making a copy 1920 */ 1921 void 1922 fdunshare(struct thread *td) 1923 { 1924 struct filedesc *tmp; 1925 struct proc *p = td->td_proc; 1926 1927 if (p->p_fd->fd_refcnt == 1) 1928 return; 1929 1930 tmp = fdcopy(p->p_fd); 1931 fdescfree(td); 1932 p->p_fd = tmp; 1933 } 1934 1935 void 1936 fdinstall_remapped(struct thread *td, struct filedesc *fdp) 1937 { 1938 1939 fdescfree(td); 1940 td->td_proc->p_fd = fdp; 1941 } 1942 1943 /* 1944 * Copy a filedesc structure. A NULL pointer in returns a NULL reference, 1945 * this is to ease callers, not catch errors. 1946 */ 1947 struct filedesc * 1948 fdcopy(struct filedesc *fdp) 1949 { 1950 struct filedesc *newfdp; 1951 struct filedescent *nfde, *ofde; 1952 int i; 1953 1954 MPASS(fdp != NULL); 1955 1956 newfdp = fdinit(fdp, true); 1957 /* copy all passable descriptors (i.e. not kqueue) */ 1958 newfdp->fd_freefile = -1; 1959 for (i = 0; i <= fdp->fd_lastfile; ++i) { 1960 ofde = &fdp->fd_ofiles[i]; 1961 if (ofde->fde_file == NULL || 1962 (ofde->fde_file->f_ops->fo_flags & DFLAG_PASSABLE) == 0) { 1963 if (newfdp->fd_freefile == -1) 1964 newfdp->fd_freefile = i; 1965 continue; 1966 } 1967 nfde = &newfdp->fd_ofiles[i]; 1968 *nfde = *ofde; 1969 filecaps_copy(&ofde->fde_caps, &nfde->fde_caps, true); 1970 fhold(nfde->fde_file); 1971 fdused_init(newfdp, i); 1972 newfdp->fd_lastfile = i; 1973 } 1974 if (newfdp->fd_freefile == -1) 1975 newfdp->fd_freefile = i; 1976 newfdp->fd_cmask = fdp->fd_cmask; 1977 FILEDESC_SUNLOCK(fdp); 1978 return (newfdp); 1979 } 1980 1981 /* 1982 * Copies a filedesc structure, while remapping all file descriptors 1983 * stored inside using a translation table. 1984 * 1985 * File descriptors are copied over to the new file descriptor table, 1986 * regardless of whether the close-on-exec flag is set. 1987 */ 1988 int 1989 fdcopy_remapped(struct filedesc *fdp, const int *fds, size_t nfds, 1990 struct filedesc **ret) 1991 { 1992 struct filedesc *newfdp; 1993 struct filedescent *nfde, *ofde; 1994 int error, i; 1995 1996 MPASS(fdp != NULL); 1997 1998 newfdp = fdinit(fdp, true); 1999 if (nfds > fdp->fd_lastfile + 1) { 2000 /* New table cannot be larger than the old one. */ 2001 error = E2BIG; 2002 goto bad; 2003 } 2004 /* Copy all passable descriptors (i.e. not kqueue). */ 2005 newfdp->fd_freefile = nfds; 2006 for (i = 0; i < nfds; ++i) { 2007 if (fds[i] < 0 || fds[i] > fdp->fd_lastfile) { 2008 /* File descriptor out of bounds. */ 2009 error = EBADF; 2010 goto bad; 2011 } 2012 ofde = &fdp->fd_ofiles[fds[i]]; 2013 if (ofde->fde_file == NULL) { 2014 /* Unused file descriptor. */ 2015 error = EBADF; 2016 goto bad; 2017 } 2018 if ((ofde->fde_file->f_ops->fo_flags & DFLAG_PASSABLE) == 0) { 2019 /* File descriptor cannot be passed. */ 2020 error = EINVAL; 2021 goto bad; 2022 } 2023 nfde = &newfdp->fd_ofiles[i]; 2024 *nfde = *ofde; 2025 filecaps_copy(&ofde->fde_caps, &nfde->fde_caps, true); 2026 fhold(nfde->fde_file); 2027 fdused_init(newfdp, i); 2028 newfdp->fd_lastfile = i; 2029 } 2030 newfdp->fd_cmask = fdp->fd_cmask; 2031 FILEDESC_SUNLOCK(fdp); 2032 *ret = newfdp; 2033 return (0); 2034 bad: 2035 FILEDESC_SUNLOCK(fdp); 2036 fdescfree_remapped(newfdp); 2037 return (error); 2038 } 2039 2040 /* 2041 * Clear POSIX style locks. This is only used when fdp looses a reference (i.e. 2042 * one of processes using it exits) and the table used to be shared. 2043 */ 2044 static void 2045 fdclearlocks(struct thread *td) 2046 { 2047 struct filedesc *fdp; 2048 struct filedesc_to_leader *fdtol; 2049 struct flock lf; 2050 struct file *fp; 2051 struct proc *p; 2052 struct vnode *vp; 2053 int i; 2054 2055 p = td->td_proc; 2056 fdp = p->p_fd; 2057 fdtol = p->p_fdtol; 2058 MPASS(fdtol != NULL); 2059 2060 FILEDESC_XLOCK(fdp); 2061 KASSERT(fdtol->fdl_refcount > 0, 2062 ("filedesc_to_refcount botch: fdl_refcount=%d", 2063 fdtol->fdl_refcount)); 2064 if (fdtol->fdl_refcount == 1 && 2065 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 2066 for (i = 0; i <= fdp->fd_lastfile; i++) { 2067 fp = fdp->fd_ofiles[i].fde_file; 2068 if (fp == NULL || fp->f_type != DTYPE_VNODE) 2069 continue; 2070 fhold(fp); 2071 FILEDESC_XUNLOCK(fdp); 2072 lf.l_whence = SEEK_SET; 2073 lf.l_start = 0; 2074 lf.l_len = 0; 2075 lf.l_type = F_UNLCK; 2076 vp = fp->f_vnode; 2077 (void) VOP_ADVLOCK(vp, 2078 (caddr_t)p->p_leader, F_UNLCK, 2079 &lf, F_POSIX); 2080 FILEDESC_XLOCK(fdp); 2081 fdrop(fp, td); 2082 } 2083 } 2084 retry: 2085 if (fdtol->fdl_refcount == 1) { 2086 if (fdp->fd_holdleaderscount > 0 && 2087 (p->p_leader->p_flag & P_ADVLOCK) != 0) { 2088 /* 2089 * close() or kern_dup() has cleared a reference 2090 * in a shared file descriptor table. 2091 */ 2092 fdp->fd_holdleaderswakeup = 1; 2093 sx_sleep(&fdp->fd_holdleaderscount, 2094 FILEDESC_LOCK(fdp), PLOCK, "fdlhold", 0); 2095 goto retry; 2096 } 2097 if (fdtol->fdl_holdcount > 0) { 2098 /* 2099 * Ensure that fdtol->fdl_leader remains 2100 * valid in closef(). 2101 */ 2102 fdtol->fdl_wakeup = 1; 2103 sx_sleep(fdtol, FILEDESC_LOCK(fdp), PLOCK, 2104 "fdlhold", 0); 2105 goto retry; 2106 } 2107 } 2108 fdtol->fdl_refcount--; 2109 if (fdtol->fdl_refcount == 0 && 2110 fdtol->fdl_holdcount == 0) { 2111 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 2112 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 2113 } else 2114 fdtol = NULL; 2115 p->p_fdtol = NULL; 2116 FILEDESC_XUNLOCK(fdp); 2117 if (fdtol != NULL) 2118 free(fdtol, M_FILEDESC_TO_LEADER); 2119 } 2120 2121 /* 2122 * Release a filedesc structure. 2123 */ 2124 static void 2125 fdescfree_fds(struct thread *td, struct filedesc *fdp, bool needclose) 2126 { 2127 struct filedesc0 *fdp0; 2128 struct freetable *ft, *tft; 2129 struct filedescent *fde; 2130 struct file *fp; 2131 int i; 2132 2133 for (i = 0; i <= fdp->fd_lastfile; i++) { 2134 fde = &fdp->fd_ofiles[i]; 2135 fp = fde->fde_file; 2136 if (fp != NULL) { 2137 fdefree_last(fde); 2138 if (needclose) 2139 (void) closef(fp, td); 2140 else 2141 fdrop(fp, td); 2142 } 2143 } 2144 2145 if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE)) 2146 free(fdp->fd_map, M_FILEDESC); 2147 if (fdp->fd_nfiles > NDFILE) 2148 free(fdp->fd_files, M_FILEDESC); 2149 2150 fdp0 = (struct filedesc0 *)fdp; 2151 SLIST_FOREACH_SAFE(ft, &fdp0->fd_free, ft_next, tft) 2152 free(ft->ft_table, M_FILEDESC); 2153 2154 fddrop(fdp); 2155 } 2156 2157 void 2158 fdescfree(struct thread *td) 2159 { 2160 struct proc *p; 2161 struct filedesc *fdp; 2162 struct vnode *cdir, *jdir, *rdir; 2163 2164 p = td->td_proc; 2165 fdp = p->p_fd; 2166 MPASS(fdp != NULL); 2167 2168 #ifdef RACCT 2169 if (racct_enable) { 2170 PROC_LOCK(p); 2171 racct_set(p, RACCT_NOFILE, 0); 2172 PROC_UNLOCK(p); 2173 } 2174 #endif 2175 2176 if (p->p_fdtol != NULL) 2177 fdclearlocks(td); 2178 2179 PROC_LOCK(p); 2180 p->p_fd = NULL; 2181 PROC_UNLOCK(p); 2182 2183 if (refcount_release(&fdp->fd_refcnt) == 0) 2184 return; 2185 2186 FILEDESC_XLOCK(fdp); 2187 cdir = fdp->fd_cdir; 2188 fdp->fd_cdir = NULL; 2189 rdir = fdp->fd_rdir; 2190 fdp->fd_rdir = NULL; 2191 jdir = fdp->fd_jdir; 2192 fdp->fd_jdir = NULL; 2193 FILEDESC_XUNLOCK(fdp); 2194 2195 if (cdir != NULL) 2196 vrele(cdir); 2197 if (rdir != NULL) 2198 vrele(rdir); 2199 if (jdir != NULL) 2200 vrele(jdir); 2201 2202 fdescfree_fds(td, fdp, 1); 2203 } 2204 2205 void 2206 fdescfree_remapped(struct filedesc *fdp) 2207 { 2208 2209 if (fdp->fd_cdir != NULL) 2210 vrele(fdp->fd_cdir); 2211 if (fdp->fd_rdir != NULL) 2212 vrele(fdp->fd_rdir); 2213 if (fdp->fd_jdir != NULL) 2214 vrele(fdp->fd_jdir); 2215 2216 fdescfree_fds(curthread, fdp, 0); 2217 } 2218 2219 /* 2220 * For setugid programs, we don't want to people to use that setugidness 2221 * to generate error messages which write to a file which otherwise would 2222 * otherwise be off-limits to the process. We check for filesystems where 2223 * the vnode can change out from under us after execve (like [lin]procfs). 2224 * 2225 * Since fdsetugidsafety calls this only for fd 0, 1 and 2, this check is 2226 * sufficient. We also don't check for setugidness since we know we are. 2227 */ 2228 static bool 2229 is_unsafe(struct file *fp) 2230 { 2231 struct vnode *vp; 2232 2233 if (fp->f_type != DTYPE_VNODE) 2234 return (false); 2235 2236 vp = fp->f_vnode; 2237 return ((vp->v_vflag & VV_PROCDEP) != 0); 2238 } 2239 2240 /* 2241 * Make this setguid thing safe, if at all possible. 2242 */ 2243 void 2244 fdsetugidsafety(struct thread *td) 2245 { 2246 struct filedesc *fdp; 2247 struct file *fp; 2248 int i; 2249 2250 fdp = td->td_proc->p_fd; 2251 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 2252 MPASS(fdp->fd_nfiles >= 3); 2253 for (i = 0; i <= 2; i++) { 2254 fp = fdp->fd_ofiles[i].fde_file; 2255 if (fp != NULL && is_unsafe(fp)) { 2256 FILEDESC_XLOCK(fdp); 2257 knote_fdclose(td, i); 2258 /* 2259 * NULL-out descriptor prior to close to avoid 2260 * a race while close blocks. 2261 */ 2262 fdfree(fdp, i); 2263 FILEDESC_XUNLOCK(fdp); 2264 (void) closef(fp, td); 2265 } 2266 } 2267 } 2268 2269 /* 2270 * If a specific file object occupies a specific file descriptor, close the 2271 * file descriptor entry and drop a reference on the file object. This is a 2272 * convenience function to handle a subsequent error in a function that calls 2273 * falloc() that handles the race that another thread might have closed the 2274 * file descriptor out from under the thread creating the file object. 2275 */ 2276 void 2277 fdclose(struct thread *td, struct file *fp, int idx) 2278 { 2279 struct filedesc *fdp = td->td_proc->p_fd; 2280 2281 FILEDESC_XLOCK(fdp); 2282 if (fdp->fd_ofiles[idx].fde_file == fp) { 2283 fdfree(fdp, idx); 2284 FILEDESC_XUNLOCK(fdp); 2285 fdrop(fp, td); 2286 } else 2287 FILEDESC_XUNLOCK(fdp); 2288 } 2289 2290 /* 2291 * Close any files on exec? 2292 */ 2293 void 2294 fdcloseexec(struct thread *td) 2295 { 2296 struct filedesc *fdp; 2297 struct filedescent *fde; 2298 struct file *fp; 2299 int i; 2300 2301 fdp = td->td_proc->p_fd; 2302 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 2303 for (i = 0; i <= fdp->fd_lastfile; i++) { 2304 fde = &fdp->fd_ofiles[i]; 2305 fp = fde->fde_file; 2306 if (fp != NULL && (fp->f_type == DTYPE_MQUEUE || 2307 (fde->fde_flags & UF_EXCLOSE))) { 2308 FILEDESC_XLOCK(fdp); 2309 fdfree(fdp, i); 2310 (void) closefp(fdp, i, fp, td, 0); 2311 FILEDESC_UNLOCK_ASSERT(fdp); 2312 } 2313 } 2314 } 2315 2316 /* 2317 * It is unsafe for set[ug]id processes to be started with file 2318 * descriptors 0..2 closed, as these descriptors are given implicit 2319 * significance in the Standard C library. fdcheckstd() will create a 2320 * descriptor referencing /dev/null for each of stdin, stdout, and 2321 * stderr that is not already open. 2322 */ 2323 int 2324 fdcheckstd(struct thread *td) 2325 { 2326 struct filedesc *fdp; 2327 register_t save; 2328 int i, error, devnull; 2329 2330 fdp = td->td_proc->p_fd; 2331 KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared")); 2332 MPASS(fdp->fd_nfiles >= 3); 2333 devnull = -1; 2334 for (i = 0; i <= 2; i++) { 2335 if (fdp->fd_ofiles[i].fde_file != NULL) 2336 continue; 2337 2338 save = td->td_retval[0]; 2339 if (devnull != -1) { 2340 error = kern_dup(td, FDDUP_FIXED, 0, devnull, i); 2341 } else { 2342 error = kern_openat(td, AT_FDCWD, "/dev/null", 2343 UIO_SYSSPACE, O_RDWR, 0); 2344 if (error == 0) { 2345 devnull = td->td_retval[0]; 2346 KASSERT(devnull == i, ("we didn't get our fd")); 2347 } 2348 } 2349 td->td_retval[0] = save; 2350 if (error != 0) 2351 return (error); 2352 } 2353 return (0); 2354 } 2355 2356 /* 2357 * Internal form of close. Decrement reference count on file structure. 2358 * Note: td may be NULL when closing a file that was being passed in a 2359 * message. 2360 * 2361 * XXXRW: Giant is not required for the caller, but often will be held; this 2362 * makes it moderately likely the Giant will be recursed in the VFS case. 2363 */ 2364 int 2365 closef(struct file *fp, struct thread *td) 2366 { 2367 struct vnode *vp; 2368 struct flock lf; 2369 struct filedesc_to_leader *fdtol; 2370 struct filedesc *fdp; 2371 2372 /* 2373 * POSIX record locking dictates that any close releases ALL 2374 * locks owned by this process. This is handled by setting 2375 * a flag in the unlock to free ONLY locks obeying POSIX 2376 * semantics, and not to free BSD-style file locks. 2377 * If the descriptor was in a message, POSIX-style locks 2378 * aren't passed with the descriptor, and the thread pointer 2379 * will be NULL. Callers should be careful only to pass a 2380 * NULL thread pointer when there really is no owning 2381 * context that might have locks, or the locks will be 2382 * leaked. 2383 */ 2384 if (fp->f_type == DTYPE_VNODE && td != NULL) { 2385 vp = fp->f_vnode; 2386 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) { 2387 lf.l_whence = SEEK_SET; 2388 lf.l_start = 0; 2389 lf.l_len = 0; 2390 lf.l_type = F_UNLCK; 2391 (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader, 2392 F_UNLCK, &lf, F_POSIX); 2393 } 2394 fdtol = td->td_proc->p_fdtol; 2395 if (fdtol != NULL) { 2396 /* 2397 * Handle special case where file descriptor table is 2398 * shared between multiple process leaders. 2399 */ 2400 fdp = td->td_proc->p_fd; 2401 FILEDESC_XLOCK(fdp); 2402 for (fdtol = fdtol->fdl_next; 2403 fdtol != td->td_proc->p_fdtol; 2404 fdtol = fdtol->fdl_next) { 2405 if ((fdtol->fdl_leader->p_flag & 2406 P_ADVLOCK) == 0) 2407 continue; 2408 fdtol->fdl_holdcount++; 2409 FILEDESC_XUNLOCK(fdp); 2410 lf.l_whence = SEEK_SET; 2411 lf.l_start = 0; 2412 lf.l_len = 0; 2413 lf.l_type = F_UNLCK; 2414 vp = fp->f_vnode; 2415 (void) VOP_ADVLOCK(vp, 2416 (caddr_t)fdtol->fdl_leader, F_UNLCK, &lf, 2417 F_POSIX); 2418 FILEDESC_XLOCK(fdp); 2419 fdtol->fdl_holdcount--; 2420 if (fdtol->fdl_holdcount == 0 && 2421 fdtol->fdl_wakeup != 0) { 2422 fdtol->fdl_wakeup = 0; 2423 wakeup(fdtol); 2424 } 2425 } 2426 FILEDESC_XUNLOCK(fdp); 2427 } 2428 } 2429 return (fdrop(fp, td)); 2430 } 2431 2432 /* 2433 * Initialize the file pointer with the specified properties. 2434 * 2435 * The ops are set with release semantics to be certain that the flags, type, 2436 * and data are visible when ops is. This is to prevent ops methods from being 2437 * called with bad data. 2438 */ 2439 void 2440 finit(struct file *fp, u_int flag, short type, void *data, struct fileops *ops) 2441 { 2442 fp->f_data = data; 2443 fp->f_flag = flag; 2444 fp->f_type = type; 2445 atomic_store_rel_ptr((volatile uintptr_t *)&fp->f_ops, (uintptr_t)ops); 2446 } 2447 2448 int 2449 fget_cap_locked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 2450 struct file **fpp, struct filecaps *havecapsp) 2451 { 2452 struct filedescent *fde; 2453 int error; 2454 2455 FILEDESC_LOCK_ASSERT(fdp); 2456 2457 fde = fdeget_locked(fdp, fd); 2458 if (fde == NULL) { 2459 error = EBADF; 2460 goto out; 2461 } 2462 2463 #ifdef CAPABILITIES 2464 error = cap_check(cap_rights_fde(fde), needrightsp); 2465 if (error != 0) 2466 goto out; 2467 #endif 2468 2469 if (havecapsp != NULL) 2470 filecaps_copy(&fde->fde_caps, havecapsp, true); 2471 2472 fhold(fde->fde_file); 2473 *fpp = fde->fde_file; 2474 2475 error = 0; 2476 out: 2477 return (error); 2478 } 2479 2480 int 2481 fget_cap(struct thread *td, int fd, cap_rights_t *needrightsp, 2482 struct file **fpp, struct filecaps *havecapsp) 2483 { 2484 struct filedesc *fdp; 2485 struct file *fp; 2486 int error; 2487 seq_t seq; 2488 2489 fdp = td->td_proc->p_fd; 2490 for (;;) { 2491 error = fget_unlocked(fdp, fd, needrightsp, &fp, &seq); 2492 if (error != 0) 2493 return (error); 2494 2495 if (havecapsp != NULL) { 2496 if (!filecaps_copy(&fdp->fd_ofiles[fd].fde_caps, 2497 havecapsp, false)) { 2498 fdrop(fp, td); 2499 goto get_locked; 2500 } 2501 } 2502 2503 if (!fd_modified(fdp, fd, seq)) 2504 break; 2505 fdrop(fp, td); 2506 } 2507 2508 *fpp = fp; 2509 return (0); 2510 2511 get_locked: 2512 FILEDESC_SLOCK(fdp); 2513 error = fget_cap_locked(fdp, fd, needrightsp, fpp, havecapsp); 2514 FILEDESC_SUNLOCK(fdp); 2515 2516 return (error); 2517 } 2518 2519 int 2520 fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 2521 struct file **fpp, seq_t *seqp) 2522 { 2523 #ifdef CAPABILITIES 2524 struct filedescent *fde; 2525 #endif 2526 struct fdescenttbl *fdt; 2527 struct file *fp; 2528 u_int count; 2529 #ifdef CAPABILITIES 2530 seq_t seq; 2531 cap_rights_t haverights; 2532 int error; 2533 #endif 2534 2535 fdt = fdp->fd_files; 2536 if ((u_int)fd >= fdt->fdt_nfiles) 2537 return (EBADF); 2538 /* 2539 * Fetch the descriptor locklessly. We avoid fdrop() races by 2540 * never raising a refcount above 0. To accomplish this we have 2541 * to use a cmpset loop rather than an atomic_add. The descriptor 2542 * must be re-verified once we acquire a reference to be certain 2543 * that the identity is still correct and we did not lose a race 2544 * due to preemption. 2545 */ 2546 for (;;) { 2547 #ifdef CAPABILITIES 2548 seq = seq_read(fd_seq(fdt, fd)); 2549 fde = &fdt->fdt_ofiles[fd]; 2550 haverights = *cap_rights_fde(fde); 2551 fp = fde->fde_file; 2552 if (!seq_consistent(fd_seq(fdt, fd), seq)) { 2553 cpu_spinwait(); 2554 continue; 2555 } 2556 #else 2557 fp = fdt->fdt_ofiles[fd].fde_file; 2558 #endif 2559 if (fp == NULL) 2560 return (EBADF); 2561 #ifdef CAPABILITIES 2562 error = cap_check(&haverights, needrightsp); 2563 if (error != 0) 2564 return (error); 2565 #endif 2566 retry: 2567 count = fp->f_count; 2568 if (count == 0) { 2569 /* 2570 * Force a reload. Other thread could reallocate the 2571 * table before this fd was closed, so it possible that 2572 * there is a stale fp pointer in cached version. 2573 */ 2574 fdt = *(struct fdescenttbl * volatile *)&(fdp->fd_files); 2575 continue; 2576 } 2577 /* 2578 * Use an acquire barrier to force re-reading of fdt so it is 2579 * refreshed for verification. 2580 */ 2581 if (atomic_cmpset_acq_int(&fp->f_count, count, count + 1) == 0) 2582 goto retry; 2583 fdt = fdp->fd_files; 2584 #ifdef CAPABILITIES 2585 if (seq_consistent_nomb(fd_seq(fdt, fd), seq)) 2586 #else 2587 if (fp == fdt->fdt_ofiles[fd].fde_file) 2588 #endif 2589 break; 2590 fdrop(fp, curthread); 2591 } 2592 *fpp = fp; 2593 if (seqp != NULL) { 2594 #ifdef CAPABILITIES 2595 *seqp = seq; 2596 #endif 2597 } 2598 return (0); 2599 } 2600 2601 /* 2602 * Extract the file pointer associated with the specified descriptor for the 2603 * current user process. 2604 * 2605 * If the descriptor doesn't exist or doesn't match 'flags', EBADF is 2606 * returned. 2607 * 2608 * File's rights will be checked against the capability rights mask. 2609 * 2610 * If an error occurred the non-zero error is returned and *fpp is set to 2611 * NULL. Otherwise *fpp is held and set and zero is returned. Caller is 2612 * responsible for fdrop(). 2613 */ 2614 static __inline int 2615 _fget(struct thread *td, int fd, struct file **fpp, int flags, 2616 cap_rights_t *needrightsp, seq_t *seqp) 2617 { 2618 struct filedesc *fdp; 2619 struct file *fp; 2620 int error; 2621 2622 *fpp = NULL; 2623 fdp = td->td_proc->p_fd; 2624 error = fget_unlocked(fdp, fd, needrightsp, &fp, seqp); 2625 if (error != 0) 2626 return (error); 2627 if (fp->f_ops == &badfileops) { 2628 fdrop(fp, td); 2629 return (EBADF); 2630 } 2631 2632 /* 2633 * FREAD and FWRITE failure return EBADF as per POSIX. 2634 */ 2635 error = 0; 2636 switch (flags) { 2637 case FREAD: 2638 case FWRITE: 2639 if ((fp->f_flag & flags) == 0) 2640 error = EBADF; 2641 break; 2642 case FEXEC: 2643 if ((fp->f_flag & (FREAD | FEXEC)) == 0 || 2644 ((fp->f_flag & FWRITE) != 0)) 2645 error = EBADF; 2646 break; 2647 case 0: 2648 break; 2649 default: 2650 KASSERT(0, ("wrong flags")); 2651 } 2652 2653 if (error != 0) { 2654 fdrop(fp, td); 2655 return (error); 2656 } 2657 2658 *fpp = fp; 2659 return (0); 2660 } 2661 2662 int 2663 fget(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp) 2664 { 2665 2666 return (_fget(td, fd, fpp, 0, rightsp, NULL)); 2667 } 2668 2669 int 2670 fget_mmap(struct thread *td, int fd, cap_rights_t *rightsp, u_char *maxprotp, 2671 struct file **fpp) 2672 { 2673 int error; 2674 #ifndef CAPABILITIES 2675 error = _fget(td, fd, fpp, 0, rightsp, NULL); 2676 if (maxprotp != NULL) 2677 *maxprotp = VM_PROT_ALL; 2678 #else 2679 struct filedesc *fdp = td->td_proc->p_fd; 2680 seq_t seq; 2681 2682 MPASS(cap_rights_is_set(rightsp, CAP_MMAP)); 2683 for (;;) { 2684 error = _fget(td, fd, fpp, 0, rightsp, &seq); 2685 if (error != 0) 2686 return (error); 2687 /* 2688 * If requested, convert capability rights to access flags. 2689 */ 2690 if (maxprotp != NULL) 2691 *maxprotp = cap_rights_to_vmprot(cap_rights(fdp, fd)); 2692 if (!fd_modified(fdp, fd, seq)) 2693 break; 2694 fdrop(*fpp, td); 2695 } 2696 #endif 2697 return (error); 2698 } 2699 2700 int 2701 fget_read(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp) 2702 { 2703 2704 return (_fget(td, fd, fpp, FREAD, rightsp, NULL)); 2705 } 2706 2707 int 2708 fget_write(struct thread *td, int fd, cap_rights_t *rightsp, struct file **fpp) 2709 { 2710 2711 return (_fget(td, fd, fpp, FWRITE, rightsp, NULL)); 2712 } 2713 2714 int 2715 fget_fcntl(struct thread *td, int fd, cap_rights_t *rightsp, int needfcntl, 2716 struct file **fpp) 2717 { 2718 struct filedesc *fdp = td->td_proc->p_fd; 2719 #ifndef CAPABILITIES 2720 return (fget_unlocked(fdp, fd, rightsp, fpp, NULL)); 2721 #else 2722 int error; 2723 seq_t seq; 2724 2725 MPASS(cap_rights_is_set(rightsp, CAP_FCNTL)); 2726 for (;;) { 2727 error = fget_unlocked(fdp, fd, rightsp, fpp, &seq); 2728 if (error != 0) 2729 return (error); 2730 error = cap_fcntl_check(fdp, fd, needfcntl); 2731 if (!fd_modified(fdp, fd, seq)) 2732 break; 2733 fdrop(*fpp, td); 2734 } 2735 if (error != 0) { 2736 fdrop(*fpp, td); 2737 *fpp = NULL; 2738 } 2739 return (error); 2740 #endif 2741 } 2742 2743 /* 2744 * Like fget() but loads the underlying vnode, or returns an error if the 2745 * descriptor does not represent a vnode. Note that pipes use vnodes but 2746 * never have VM objects. The returned vnode will be vref()'d. 2747 * 2748 * XXX: what about the unused flags ? 2749 */ 2750 static __inline int 2751 _fgetvp(struct thread *td, int fd, int flags, cap_rights_t *needrightsp, 2752 struct vnode **vpp) 2753 { 2754 struct file *fp; 2755 int error; 2756 2757 *vpp = NULL; 2758 error = _fget(td, fd, &fp, flags, needrightsp, NULL); 2759 if (error != 0) 2760 return (error); 2761 if (fp->f_vnode == NULL) { 2762 error = EINVAL; 2763 } else { 2764 *vpp = fp->f_vnode; 2765 vref(*vpp); 2766 } 2767 fdrop(fp, td); 2768 2769 return (error); 2770 } 2771 2772 int 2773 fgetvp(struct thread *td, int fd, cap_rights_t *rightsp, struct vnode **vpp) 2774 { 2775 2776 return (_fgetvp(td, fd, 0, rightsp, vpp)); 2777 } 2778 2779 int 2780 fgetvp_rights(struct thread *td, int fd, cap_rights_t *needrightsp, 2781 struct filecaps *havecaps, struct vnode **vpp) 2782 { 2783 struct filedesc *fdp; 2784 struct file *fp; 2785 #ifdef CAPABILITIES 2786 int error; 2787 #endif 2788 2789 fdp = td->td_proc->p_fd; 2790 fp = fget_locked(fdp, fd); 2791 if (fp == NULL || fp->f_ops == &badfileops) 2792 return (EBADF); 2793 2794 #ifdef CAPABILITIES 2795 error = cap_check(cap_rights(fdp, fd), needrightsp); 2796 if (error != 0) 2797 return (error); 2798 #endif 2799 2800 if (fp->f_vnode == NULL) 2801 return (EINVAL); 2802 2803 *vpp = fp->f_vnode; 2804 vref(*vpp); 2805 filecaps_copy(&fdp->fd_ofiles[fd].fde_caps, havecaps, true); 2806 2807 return (0); 2808 } 2809 2810 int 2811 fgetvp_read(struct thread *td, int fd, cap_rights_t *rightsp, struct vnode **vpp) 2812 { 2813 2814 return (_fgetvp(td, fd, FREAD, rightsp, vpp)); 2815 } 2816 2817 int 2818 fgetvp_exec(struct thread *td, int fd, cap_rights_t *rightsp, struct vnode **vpp) 2819 { 2820 2821 return (_fgetvp(td, fd, FEXEC, rightsp, vpp)); 2822 } 2823 2824 #ifdef notyet 2825 int 2826 fgetvp_write(struct thread *td, int fd, cap_rights_t *rightsp, 2827 struct vnode **vpp) 2828 { 2829 2830 return (_fgetvp(td, fd, FWRITE, rightsp, vpp)); 2831 } 2832 #endif 2833 2834 /* 2835 * Like fget() but loads the underlying socket, or returns an error if the 2836 * descriptor does not represent a socket. 2837 * 2838 * We bump the ref count on the returned socket. XXX Also obtain the SX lock 2839 * in the future. 2840 * 2841 * Note: fgetsock() and fputsock() are deprecated, as consumers should rely 2842 * on their file descriptor reference to prevent the socket from being free'd 2843 * during use. 2844 */ 2845 int 2846 fgetsock(struct thread *td, int fd, cap_rights_t *rightsp, struct socket **spp, 2847 u_int *fflagp) 2848 { 2849 struct file *fp; 2850 int error; 2851 2852 *spp = NULL; 2853 if (fflagp != NULL) 2854 *fflagp = 0; 2855 if ((error = _fget(td, fd, &fp, 0, rightsp, NULL)) != 0) 2856 return (error); 2857 if (fp->f_type != DTYPE_SOCKET) { 2858 error = ENOTSOCK; 2859 } else { 2860 *spp = fp->f_data; 2861 if (fflagp) 2862 *fflagp = fp->f_flag; 2863 SOCK_LOCK(*spp); 2864 soref(*spp); 2865 SOCK_UNLOCK(*spp); 2866 } 2867 fdrop(fp, td); 2868 2869 return (error); 2870 } 2871 2872 /* 2873 * Drop the reference count on the socket and XXX release the SX lock in the 2874 * future. The last reference closes the socket. 2875 * 2876 * Note: fputsock() is deprecated, see comment for fgetsock(). 2877 */ 2878 void 2879 fputsock(struct socket *so) 2880 { 2881 2882 ACCEPT_LOCK(); 2883 SOCK_LOCK(so); 2884 CURVNET_SET(so->so_vnet); 2885 sorele(so); 2886 CURVNET_RESTORE(); 2887 } 2888 2889 /* 2890 * Handle the last reference to a file being closed. 2891 */ 2892 int 2893 _fdrop(struct file *fp, struct thread *td) 2894 { 2895 int error; 2896 2897 if (fp->f_count != 0) 2898 panic("fdrop: count %d", fp->f_count); 2899 error = fo_close(fp, td); 2900 atomic_subtract_int(&openfiles, 1); 2901 crfree(fp->f_cred); 2902 free(fp->f_advice, M_FADVISE); 2903 uma_zfree(file_zone, fp); 2904 2905 return (error); 2906 } 2907 2908 /* 2909 * Apply an advisory lock on a file descriptor. 2910 * 2911 * Just attempt to get a record lock of the requested type on the entire file 2912 * (l_whence = SEEK_SET, l_start = 0, l_len = 0). 2913 */ 2914 #ifndef _SYS_SYSPROTO_H_ 2915 struct flock_args { 2916 int fd; 2917 int how; 2918 }; 2919 #endif 2920 /* ARGSUSED */ 2921 int 2922 sys_flock(struct thread *td, struct flock_args *uap) 2923 { 2924 struct file *fp; 2925 struct vnode *vp; 2926 struct flock lf; 2927 cap_rights_t rights; 2928 int error; 2929 2930 error = fget(td, uap->fd, cap_rights_init(&rights, CAP_FLOCK), &fp); 2931 if (error != 0) 2932 return (error); 2933 if (fp->f_type != DTYPE_VNODE) { 2934 fdrop(fp, td); 2935 return (EOPNOTSUPP); 2936 } 2937 2938 vp = fp->f_vnode; 2939 lf.l_whence = SEEK_SET; 2940 lf.l_start = 0; 2941 lf.l_len = 0; 2942 if (uap->how & LOCK_UN) { 2943 lf.l_type = F_UNLCK; 2944 atomic_clear_int(&fp->f_flag, FHASLOCK); 2945 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); 2946 goto done2; 2947 } 2948 if (uap->how & LOCK_EX) 2949 lf.l_type = F_WRLCK; 2950 else if (uap->how & LOCK_SH) 2951 lf.l_type = F_RDLCK; 2952 else { 2953 error = EBADF; 2954 goto done2; 2955 } 2956 atomic_set_int(&fp->f_flag, FHASLOCK); 2957 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 2958 (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT); 2959 done2: 2960 fdrop(fp, td); 2961 return (error); 2962 } 2963 /* 2964 * Duplicate the specified descriptor to a free descriptor. 2965 */ 2966 int 2967 dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode, 2968 int openerror, int *indxp) 2969 { 2970 struct filedescent *newfde, *oldfde; 2971 struct file *fp; 2972 int error, indx; 2973 2974 KASSERT(openerror == ENODEV || openerror == ENXIO, 2975 ("unexpected error %d in %s", openerror, __func__)); 2976 2977 /* 2978 * If the to-be-dup'd fd number is greater than the allowed number 2979 * of file descriptors, or the fd to be dup'd has already been 2980 * closed, then reject. 2981 */ 2982 FILEDESC_XLOCK(fdp); 2983 if ((fp = fget_locked(fdp, dfd)) == NULL) { 2984 FILEDESC_XUNLOCK(fdp); 2985 return (EBADF); 2986 } 2987 2988 error = fdalloc(td, 0, &indx); 2989 if (error != 0) { 2990 FILEDESC_XUNLOCK(fdp); 2991 return (error); 2992 } 2993 2994 /* 2995 * There are two cases of interest here. 2996 * 2997 * For ENODEV simply dup (dfd) to file descriptor (indx) and return. 2998 * 2999 * For ENXIO steal away the file structure from (dfd) and store it in 3000 * (indx). (dfd) is effectively closed by this operation. 3001 */ 3002 switch (openerror) { 3003 case ENODEV: 3004 /* 3005 * Check that the mode the file is being opened for is a 3006 * subset of the mode of the existing descriptor. 3007 */ 3008 if (((mode & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) { 3009 fdunused(fdp, indx); 3010 FILEDESC_XUNLOCK(fdp); 3011 return (EACCES); 3012 } 3013 fhold(fp); 3014 newfde = &fdp->fd_ofiles[indx]; 3015 oldfde = &fdp->fd_ofiles[dfd]; 3016 #ifdef CAPABILITIES 3017 seq_write_begin(&newfde->fde_seq); 3018 #endif 3019 memcpy(newfde, oldfde, fde_change_size); 3020 filecaps_copy(&oldfde->fde_caps, &newfde->fde_caps, true); 3021 #ifdef CAPABILITIES 3022 seq_write_end(&newfde->fde_seq); 3023 #endif 3024 break; 3025 case ENXIO: 3026 /* 3027 * Steal away the file pointer from dfd and stuff it into indx. 3028 */ 3029 newfde = &fdp->fd_ofiles[indx]; 3030 oldfde = &fdp->fd_ofiles[dfd]; 3031 #ifdef CAPABILITIES 3032 seq_write_begin(&newfde->fde_seq); 3033 #endif 3034 memcpy(newfde, oldfde, fde_change_size); 3035 oldfde->fde_file = NULL; 3036 fdunused(fdp, dfd); 3037 #ifdef CAPABILITIES 3038 seq_write_end(&newfde->fde_seq); 3039 #endif 3040 break; 3041 } 3042 FILEDESC_XUNLOCK(fdp); 3043 *indxp = indx; 3044 return (0); 3045 } 3046 3047 /* 3048 * This sysctl determines if we will allow a process to chroot(2) if it 3049 * has a directory open: 3050 * 0: disallowed for all processes. 3051 * 1: allowed for processes that were not already chroot(2)'ed. 3052 * 2: allowed for all processes. 3053 */ 3054 3055 static int chroot_allow_open_directories = 1; 3056 3057 SYSCTL_INT(_kern, OID_AUTO, chroot_allow_open_directories, CTLFLAG_RW, 3058 &chroot_allow_open_directories, 0, 3059 "Allow a process to chroot(2) if it has a directory open"); 3060 3061 /* 3062 * Helper function for raised chroot(2) security function: Refuse if 3063 * any filedescriptors are open directories. 3064 */ 3065 static int 3066 chroot_refuse_vdir_fds(struct filedesc *fdp) 3067 { 3068 struct vnode *vp; 3069 struct file *fp; 3070 int fd; 3071 3072 FILEDESC_LOCK_ASSERT(fdp); 3073 3074 for (fd = 0; fd <= fdp->fd_lastfile; fd++) { 3075 fp = fget_locked(fdp, fd); 3076 if (fp == NULL) 3077 continue; 3078 if (fp->f_type == DTYPE_VNODE) { 3079 vp = fp->f_vnode; 3080 if (vp->v_type == VDIR) 3081 return (EPERM); 3082 } 3083 } 3084 return (0); 3085 } 3086 3087 /* 3088 * Common routine for kern_chroot() and jail_attach(). The caller is 3089 * responsible for invoking priv_check() and mac_vnode_check_chroot() to 3090 * authorize this operation. 3091 */ 3092 int 3093 pwd_chroot(struct thread *td, struct vnode *vp) 3094 { 3095 struct filedesc *fdp; 3096 struct vnode *oldvp; 3097 int error; 3098 3099 fdp = td->td_proc->p_fd; 3100 FILEDESC_XLOCK(fdp); 3101 if (chroot_allow_open_directories == 0 || 3102 (chroot_allow_open_directories == 1 && fdp->fd_rdir != rootvnode)) { 3103 error = chroot_refuse_vdir_fds(fdp); 3104 if (error != 0) { 3105 FILEDESC_XUNLOCK(fdp); 3106 return (error); 3107 } 3108 } 3109 oldvp = fdp->fd_rdir; 3110 VREF(vp); 3111 fdp->fd_rdir = vp; 3112 if (fdp->fd_jdir == NULL) { 3113 VREF(vp); 3114 fdp->fd_jdir = vp; 3115 } 3116 FILEDESC_XUNLOCK(fdp); 3117 vrele(oldvp); 3118 return (0); 3119 } 3120 3121 void 3122 pwd_chdir(struct thread *td, struct vnode *vp) 3123 { 3124 struct filedesc *fdp; 3125 struct vnode *oldvp; 3126 3127 fdp = td->td_proc->p_fd; 3128 FILEDESC_XLOCK(fdp); 3129 VNASSERT(vp->v_usecount > 0, vp, 3130 ("chdir to a vnode with zero usecount")); 3131 oldvp = fdp->fd_cdir; 3132 fdp->fd_cdir = vp; 3133 FILEDESC_XUNLOCK(fdp); 3134 vrele(oldvp); 3135 } 3136 3137 /* 3138 * Scan all active processes and prisons to see if any of them have a current 3139 * or root directory of `olddp'. If so, replace them with the new mount point. 3140 */ 3141 void 3142 mountcheckdirs(struct vnode *olddp, struct vnode *newdp) 3143 { 3144 struct filedesc *fdp; 3145 struct prison *pr; 3146 struct proc *p; 3147 int nrele; 3148 3149 if (vrefcnt(olddp) == 1) 3150 return; 3151 nrele = 0; 3152 sx_slock(&allproc_lock); 3153 FOREACH_PROC_IN_SYSTEM(p) { 3154 PROC_LOCK(p); 3155 fdp = fdhold(p); 3156 PROC_UNLOCK(p); 3157 if (fdp == NULL) 3158 continue; 3159 FILEDESC_XLOCK(fdp); 3160 if (fdp->fd_cdir == olddp) { 3161 vref(newdp); 3162 fdp->fd_cdir = newdp; 3163 nrele++; 3164 } 3165 if (fdp->fd_rdir == olddp) { 3166 vref(newdp); 3167 fdp->fd_rdir = newdp; 3168 nrele++; 3169 } 3170 if (fdp->fd_jdir == olddp) { 3171 vref(newdp); 3172 fdp->fd_jdir = newdp; 3173 nrele++; 3174 } 3175 FILEDESC_XUNLOCK(fdp); 3176 fddrop(fdp); 3177 } 3178 sx_sunlock(&allproc_lock); 3179 if (rootvnode == olddp) { 3180 vref(newdp); 3181 rootvnode = newdp; 3182 nrele++; 3183 } 3184 mtx_lock(&prison0.pr_mtx); 3185 if (prison0.pr_root == olddp) { 3186 vref(newdp); 3187 prison0.pr_root = newdp; 3188 nrele++; 3189 } 3190 mtx_unlock(&prison0.pr_mtx); 3191 sx_slock(&allprison_lock); 3192 TAILQ_FOREACH(pr, &allprison, pr_list) { 3193 mtx_lock(&pr->pr_mtx); 3194 if (pr->pr_root == olddp) { 3195 vref(newdp); 3196 pr->pr_root = newdp; 3197 nrele++; 3198 } 3199 mtx_unlock(&pr->pr_mtx); 3200 } 3201 sx_sunlock(&allprison_lock); 3202 while (nrele--) 3203 vrele(olddp); 3204 } 3205 3206 struct filedesc_to_leader * 3207 filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader) 3208 { 3209 struct filedesc_to_leader *fdtol; 3210 3211 fdtol = malloc(sizeof(struct filedesc_to_leader), 3212 M_FILEDESC_TO_LEADER, M_WAITOK); 3213 fdtol->fdl_refcount = 1; 3214 fdtol->fdl_holdcount = 0; 3215 fdtol->fdl_wakeup = 0; 3216 fdtol->fdl_leader = leader; 3217 if (old != NULL) { 3218 FILEDESC_XLOCK(fdp); 3219 fdtol->fdl_next = old->fdl_next; 3220 fdtol->fdl_prev = old; 3221 old->fdl_next = fdtol; 3222 fdtol->fdl_next->fdl_prev = fdtol; 3223 FILEDESC_XUNLOCK(fdp); 3224 } else { 3225 fdtol->fdl_next = fdtol; 3226 fdtol->fdl_prev = fdtol; 3227 } 3228 return (fdtol); 3229 } 3230 3231 static int 3232 sysctl_kern_proc_nfds(SYSCTL_HANDLER_ARGS) 3233 { 3234 struct filedesc *fdp; 3235 int i, count, slots; 3236 3237 if (*(int *)arg1 != 0) 3238 return (EINVAL); 3239 3240 fdp = curproc->p_fd; 3241 count = 0; 3242 FILEDESC_SLOCK(fdp); 3243 slots = NDSLOTS(fdp->fd_lastfile + 1); 3244 for (i = 0; i < slots; i++) 3245 count += bitcountl(fdp->fd_map[i]); 3246 FILEDESC_SUNLOCK(fdp); 3247 3248 return (SYSCTL_OUT(req, &count, sizeof(count))); 3249 } 3250 3251 static SYSCTL_NODE(_kern_proc, KERN_PROC_NFDS, nfds, 3252 CTLFLAG_RD|CTLFLAG_CAPRD|CTLFLAG_MPSAFE, sysctl_kern_proc_nfds, 3253 "Number of open file descriptors"); 3254 3255 /* 3256 * Get file structures globally. 3257 */ 3258 static int 3259 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 3260 { 3261 struct xfile xf; 3262 struct filedesc *fdp; 3263 struct file *fp; 3264 struct proc *p; 3265 int error, n; 3266 3267 error = sysctl_wire_old_buffer(req, 0); 3268 if (error != 0) 3269 return (error); 3270 if (req->oldptr == NULL) { 3271 n = 0; 3272 sx_slock(&allproc_lock); 3273 FOREACH_PROC_IN_SYSTEM(p) { 3274 PROC_LOCK(p); 3275 if (p->p_state == PRS_NEW) { 3276 PROC_UNLOCK(p); 3277 continue; 3278 } 3279 fdp = fdhold(p); 3280 PROC_UNLOCK(p); 3281 if (fdp == NULL) 3282 continue; 3283 /* overestimates sparse tables. */ 3284 if (fdp->fd_lastfile > 0) 3285 n += fdp->fd_lastfile; 3286 fddrop(fdp); 3287 } 3288 sx_sunlock(&allproc_lock); 3289 return (SYSCTL_OUT(req, 0, n * sizeof(xf))); 3290 } 3291 error = 0; 3292 bzero(&xf, sizeof(xf)); 3293 xf.xf_size = sizeof(xf); 3294 sx_slock(&allproc_lock); 3295 FOREACH_PROC_IN_SYSTEM(p) { 3296 PROC_LOCK(p); 3297 if (p->p_state == PRS_NEW) { 3298 PROC_UNLOCK(p); 3299 continue; 3300 } 3301 if (p_cansee(req->td, p) != 0) { 3302 PROC_UNLOCK(p); 3303 continue; 3304 } 3305 xf.xf_pid = p->p_pid; 3306 xf.xf_uid = p->p_ucred->cr_uid; 3307 fdp = fdhold(p); 3308 PROC_UNLOCK(p); 3309 if (fdp == NULL) 3310 continue; 3311 FILEDESC_SLOCK(fdp); 3312 for (n = 0; fdp->fd_refcnt > 0 && n <= fdp->fd_lastfile; ++n) { 3313 if ((fp = fdp->fd_ofiles[n].fde_file) == NULL) 3314 continue; 3315 xf.xf_fd = n; 3316 xf.xf_file = fp; 3317 xf.xf_data = fp->f_data; 3318 xf.xf_vnode = fp->f_vnode; 3319 xf.xf_type = fp->f_type; 3320 xf.xf_count = fp->f_count; 3321 xf.xf_msgcount = 0; 3322 xf.xf_offset = foffset_get(fp); 3323 xf.xf_flag = fp->f_flag; 3324 error = SYSCTL_OUT(req, &xf, sizeof(xf)); 3325 if (error) 3326 break; 3327 } 3328 FILEDESC_SUNLOCK(fdp); 3329 fddrop(fdp); 3330 if (error) 3331 break; 3332 } 3333 sx_sunlock(&allproc_lock); 3334 return (error); 3335 } 3336 3337 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE, 3338 0, 0, sysctl_kern_file, "S,xfile", "Entire file table"); 3339 3340 #ifdef KINFO_FILE_SIZE 3341 CTASSERT(sizeof(struct kinfo_file) == KINFO_FILE_SIZE); 3342 #endif 3343 3344 static int 3345 xlate_fflags(int fflags) 3346 { 3347 static const struct { 3348 int fflag; 3349 int kf_fflag; 3350 } fflags_table[] = { 3351 { FAPPEND, KF_FLAG_APPEND }, 3352 { FASYNC, KF_FLAG_ASYNC }, 3353 { FFSYNC, KF_FLAG_FSYNC }, 3354 { FHASLOCK, KF_FLAG_HASLOCK }, 3355 { FNONBLOCK, KF_FLAG_NONBLOCK }, 3356 { FREAD, KF_FLAG_READ }, 3357 { FWRITE, KF_FLAG_WRITE }, 3358 { O_CREAT, KF_FLAG_CREAT }, 3359 { O_DIRECT, KF_FLAG_DIRECT }, 3360 { O_EXCL, KF_FLAG_EXCL }, 3361 { O_EXEC, KF_FLAG_EXEC }, 3362 { O_EXLOCK, KF_FLAG_EXLOCK }, 3363 { O_NOFOLLOW, KF_FLAG_NOFOLLOW }, 3364 { O_SHLOCK, KF_FLAG_SHLOCK }, 3365 { O_TRUNC, KF_FLAG_TRUNC } 3366 }; 3367 unsigned int i; 3368 int kflags; 3369 3370 kflags = 0; 3371 for (i = 0; i < nitems(fflags_table); i++) 3372 if (fflags & fflags_table[i].fflag) 3373 kflags |= fflags_table[i].kf_fflag; 3374 return (kflags); 3375 } 3376 3377 /* Trim unused data from kf_path by truncating the structure size. */ 3378 static void 3379 pack_kinfo(struct kinfo_file *kif) 3380 { 3381 3382 kif->kf_structsize = offsetof(struct kinfo_file, kf_path) + 3383 strlen(kif->kf_path) + 1; 3384 kif->kf_structsize = roundup(kif->kf_structsize, sizeof(uint64_t)); 3385 } 3386 3387 static void 3388 export_file_to_kinfo(struct file *fp, int fd, cap_rights_t *rightsp, 3389 struct kinfo_file *kif, struct filedesc *fdp, int flags) 3390 { 3391 int error; 3392 3393 bzero(kif, sizeof(*kif)); 3394 3395 /* Set a default type to allow for empty fill_kinfo() methods. */ 3396 kif->kf_type = KF_TYPE_UNKNOWN; 3397 kif->kf_flags = xlate_fflags(fp->f_flag); 3398 if (rightsp != NULL) 3399 kif->kf_cap_rights = *rightsp; 3400 else 3401 cap_rights_init(&kif->kf_cap_rights); 3402 kif->kf_fd = fd; 3403 kif->kf_ref_count = fp->f_count; 3404 kif->kf_offset = foffset_get(fp); 3405 3406 /* 3407 * This may drop the filedesc lock, so the 'fp' cannot be 3408 * accessed after this call. 3409 */ 3410 error = fo_fill_kinfo(fp, kif, fdp); 3411 if (error == 0) 3412 kif->kf_status |= KF_ATTR_VALID; 3413 if ((flags & KERN_FILEDESC_PACK_KINFO) != 0) 3414 pack_kinfo(kif); 3415 else 3416 kif->kf_structsize = roundup2(sizeof(*kif), sizeof(uint64_t)); 3417 } 3418 3419 static void 3420 export_vnode_to_kinfo(struct vnode *vp, int fd, int fflags, 3421 struct kinfo_file *kif, int flags) 3422 { 3423 int error; 3424 3425 bzero(kif, sizeof(*kif)); 3426 3427 kif->kf_type = KF_TYPE_VNODE; 3428 error = vn_fill_kinfo_vnode(vp, kif); 3429 if (error == 0) 3430 kif->kf_status |= KF_ATTR_VALID; 3431 kif->kf_flags = xlate_fflags(fflags); 3432 cap_rights_init(&kif->kf_cap_rights); 3433 kif->kf_fd = fd; 3434 kif->kf_ref_count = -1; 3435 kif->kf_offset = -1; 3436 if ((flags & KERN_FILEDESC_PACK_KINFO) != 0) 3437 pack_kinfo(kif); 3438 else 3439 kif->kf_structsize = roundup2(sizeof(*kif), sizeof(uint64_t)); 3440 vrele(vp); 3441 } 3442 3443 struct export_fd_buf { 3444 struct filedesc *fdp; 3445 struct sbuf *sb; 3446 ssize_t remainder; 3447 struct kinfo_file kif; 3448 int flags; 3449 }; 3450 3451 static int 3452 export_kinfo_to_sb(struct export_fd_buf *efbuf) 3453 { 3454 struct kinfo_file *kif; 3455 3456 kif = &efbuf->kif; 3457 if (efbuf->remainder != -1) { 3458 if (efbuf->remainder < kif->kf_structsize) { 3459 /* Terminate export. */ 3460 efbuf->remainder = 0; 3461 return (0); 3462 } 3463 efbuf->remainder -= kif->kf_structsize; 3464 } 3465 return (sbuf_bcat(efbuf->sb, kif, kif->kf_structsize) == 0 ? 0 : ENOMEM); 3466 } 3467 3468 static int 3469 export_file_to_sb(struct file *fp, int fd, cap_rights_t *rightsp, 3470 struct export_fd_buf *efbuf) 3471 { 3472 int error; 3473 3474 if (efbuf->remainder == 0) 3475 return (0); 3476 export_file_to_kinfo(fp, fd, rightsp, &efbuf->kif, efbuf->fdp, 3477 efbuf->flags); 3478 FILEDESC_SUNLOCK(efbuf->fdp); 3479 error = export_kinfo_to_sb(efbuf); 3480 FILEDESC_SLOCK(efbuf->fdp); 3481 return (error); 3482 } 3483 3484 static int 3485 export_vnode_to_sb(struct vnode *vp, int fd, int fflags, 3486 struct export_fd_buf *efbuf) 3487 { 3488 int error; 3489 3490 if (efbuf->remainder == 0) 3491 return (0); 3492 if (efbuf->fdp != NULL) 3493 FILEDESC_SUNLOCK(efbuf->fdp); 3494 export_vnode_to_kinfo(vp, fd, fflags, &efbuf->kif, efbuf->flags); 3495 error = export_kinfo_to_sb(efbuf); 3496 if (efbuf->fdp != NULL) 3497 FILEDESC_SLOCK(efbuf->fdp); 3498 return (error); 3499 } 3500 3501 /* 3502 * Store a process file descriptor information to sbuf. 3503 * 3504 * Takes a locked proc as argument, and returns with the proc unlocked. 3505 */ 3506 int 3507 kern_proc_filedesc_out(struct proc *p, struct sbuf *sb, ssize_t maxlen, 3508 int flags) 3509 { 3510 struct file *fp; 3511 struct filedesc *fdp; 3512 struct export_fd_buf *efbuf; 3513 struct vnode *cttyvp, *textvp, *tracevp; 3514 int error, i; 3515 cap_rights_t rights; 3516 3517 PROC_LOCK_ASSERT(p, MA_OWNED); 3518 3519 /* ktrace vnode */ 3520 tracevp = p->p_tracevp; 3521 if (tracevp != NULL) 3522 vref(tracevp); 3523 /* text vnode */ 3524 textvp = p->p_textvp; 3525 if (textvp != NULL) 3526 vref(textvp); 3527 /* Controlling tty. */ 3528 cttyvp = NULL; 3529 if (p->p_pgrp != NULL && p->p_pgrp->pg_session != NULL) { 3530 cttyvp = p->p_pgrp->pg_session->s_ttyvp; 3531 if (cttyvp != NULL) 3532 vref(cttyvp); 3533 } 3534 fdp = fdhold(p); 3535 PROC_UNLOCK(p); 3536 efbuf = malloc(sizeof(*efbuf), M_TEMP, M_WAITOK); 3537 efbuf->fdp = NULL; 3538 efbuf->sb = sb; 3539 efbuf->remainder = maxlen; 3540 efbuf->flags = flags; 3541 if (tracevp != NULL) 3542 export_vnode_to_sb(tracevp, KF_FD_TYPE_TRACE, FREAD | FWRITE, 3543 efbuf); 3544 if (textvp != NULL) 3545 export_vnode_to_sb(textvp, KF_FD_TYPE_TEXT, FREAD, efbuf); 3546 if (cttyvp != NULL) 3547 export_vnode_to_sb(cttyvp, KF_FD_TYPE_CTTY, FREAD | FWRITE, 3548 efbuf); 3549 error = 0; 3550 if (fdp == NULL) 3551 goto fail; 3552 efbuf->fdp = fdp; 3553 FILEDESC_SLOCK(fdp); 3554 /* working directory */ 3555 if (fdp->fd_cdir != NULL) { 3556 vref(fdp->fd_cdir); 3557 export_vnode_to_sb(fdp->fd_cdir, KF_FD_TYPE_CWD, FREAD, efbuf); 3558 } 3559 /* root directory */ 3560 if (fdp->fd_rdir != NULL) { 3561 vref(fdp->fd_rdir); 3562 export_vnode_to_sb(fdp->fd_rdir, KF_FD_TYPE_ROOT, FREAD, efbuf); 3563 } 3564 /* jail directory */ 3565 if (fdp->fd_jdir != NULL) { 3566 vref(fdp->fd_jdir); 3567 export_vnode_to_sb(fdp->fd_jdir, KF_FD_TYPE_JAIL, FREAD, efbuf); 3568 } 3569 for (i = 0; fdp->fd_refcnt > 0 && i <= fdp->fd_lastfile; i++) { 3570 if ((fp = fdp->fd_ofiles[i].fde_file) == NULL) 3571 continue; 3572 #ifdef CAPABILITIES 3573 rights = *cap_rights(fdp, i); 3574 #else /* !CAPABILITIES */ 3575 cap_rights_init(&rights); 3576 #endif 3577 /* 3578 * Create sysctl entry. It is OK to drop the filedesc 3579 * lock inside of export_file_to_sb() as we will 3580 * re-validate and re-evaluate its properties when the 3581 * loop continues. 3582 */ 3583 error = export_file_to_sb(fp, i, &rights, efbuf); 3584 if (error != 0 || efbuf->remainder == 0) 3585 break; 3586 } 3587 FILEDESC_SUNLOCK(fdp); 3588 fddrop(fdp); 3589 fail: 3590 free(efbuf, M_TEMP); 3591 return (error); 3592 } 3593 3594 #define FILEDESC_SBUF_SIZE (sizeof(struct kinfo_file) * 5) 3595 3596 /* 3597 * Get per-process file descriptors for use by procstat(1), et al. 3598 */ 3599 static int 3600 sysctl_kern_proc_filedesc(SYSCTL_HANDLER_ARGS) 3601 { 3602 struct sbuf sb; 3603 struct proc *p; 3604 ssize_t maxlen; 3605 int error, error2, *name; 3606 3607 name = (int *)arg1; 3608 3609 sbuf_new_for_sysctl(&sb, NULL, FILEDESC_SBUF_SIZE, req); 3610 sbuf_clear_flags(&sb, SBUF_INCLUDENUL); 3611 error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p); 3612 if (error != 0) { 3613 sbuf_delete(&sb); 3614 return (error); 3615 } 3616 maxlen = req->oldptr != NULL ? req->oldlen : -1; 3617 error = kern_proc_filedesc_out(p, &sb, maxlen, 3618 KERN_FILEDESC_PACK_KINFO); 3619 error2 = sbuf_finish(&sb); 3620 sbuf_delete(&sb); 3621 return (error != 0 ? error : error2); 3622 } 3623 3624 #ifdef KINFO_OFILE_SIZE 3625 CTASSERT(sizeof(struct kinfo_ofile) == KINFO_OFILE_SIZE); 3626 #endif 3627 3628 #ifdef COMPAT_FREEBSD7 3629 static void 3630 kinfo_to_okinfo(struct kinfo_file *kif, struct kinfo_ofile *okif) 3631 { 3632 3633 okif->kf_structsize = sizeof(*okif); 3634 okif->kf_type = kif->kf_type; 3635 okif->kf_fd = kif->kf_fd; 3636 okif->kf_ref_count = kif->kf_ref_count; 3637 okif->kf_flags = kif->kf_flags & (KF_FLAG_READ | KF_FLAG_WRITE | 3638 KF_FLAG_APPEND | KF_FLAG_ASYNC | KF_FLAG_FSYNC | KF_FLAG_NONBLOCK | 3639 KF_FLAG_DIRECT | KF_FLAG_HASLOCK); 3640 okif->kf_offset = kif->kf_offset; 3641 okif->kf_vnode_type = kif->kf_vnode_type; 3642 okif->kf_sock_domain = kif->kf_sock_domain; 3643 okif->kf_sock_type = kif->kf_sock_type; 3644 okif->kf_sock_protocol = kif->kf_sock_protocol; 3645 strlcpy(okif->kf_path, kif->kf_path, sizeof(okif->kf_path)); 3646 okif->kf_sa_local = kif->kf_sa_local; 3647 okif->kf_sa_peer = kif->kf_sa_peer; 3648 } 3649 3650 static int 3651 export_vnode_for_osysctl(struct vnode *vp, int type, struct kinfo_file *kif, 3652 struct kinfo_ofile *okif, struct filedesc *fdp, struct sysctl_req *req) 3653 { 3654 int error; 3655 3656 vref(vp); 3657 FILEDESC_SUNLOCK(fdp); 3658 export_vnode_to_kinfo(vp, type, 0, kif, KERN_FILEDESC_PACK_KINFO); 3659 kinfo_to_okinfo(kif, okif); 3660 error = SYSCTL_OUT(req, okif, sizeof(*okif)); 3661 FILEDESC_SLOCK(fdp); 3662 return (error); 3663 } 3664 3665 /* 3666 * Get per-process file descriptors for use by procstat(1), et al. 3667 */ 3668 static int 3669 sysctl_kern_proc_ofiledesc(SYSCTL_HANDLER_ARGS) 3670 { 3671 struct kinfo_ofile *okif; 3672 struct kinfo_file *kif; 3673 struct filedesc *fdp; 3674 int error, i, *name; 3675 struct file *fp; 3676 struct proc *p; 3677 3678 name = (int *)arg1; 3679 error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p); 3680 if (error != 0) 3681 return (error); 3682 fdp = fdhold(p); 3683 PROC_UNLOCK(p); 3684 if (fdp == NULL) 3685 return (ENOENT); 3686 kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK); 3687 okif = malloc(sizeof(*okif), M_TEMP, M_WAITOK); 3688 FILEDESC_SLOCK(fdp); 3689 if (fdp->fd_cdir != NULL) 3690 export_vnode_for_osysctl(fdp->fd_cdir, KF_FD_TYPE_CWD, kif, 3691 okif, fdp, req); 3692 if (fdp->fd_rdir != NULL) 3693 export_vnode_for_osysctl(fdp->fd_rdir, KF_FD_TYPE_ROOT, kif, 3694 okif, fdp, req); 3695 if (fdp->fd_jdir != NULL) 3696 export_vnode_for_osysctl(fdp->fd_jdir, KF_FD_TYPE_JAIL, kif, 3697 okif, fdp, req); 3698 for (i = 0; fdp->fd_refcnt > 0 && i <= fdp->fd_lastfile; i++) { 3699 if ((fp = fdp->fd_ofiles[i].fde_file) == NULL) 3700 continue; 3701 export_file_to_kinfo(fp, i, NULL, kif, fdp, 3702 KERN_FILEDESC_PACK_KINFO); 3703 FILEDESC_SUNLOCK(fdp); 3704 kinfo_to_okinfo(kif, okif); 3705 error = SYSCTL_OUT(req, okif, sizeof(*okif)); 3706 FILEDESC_SLOCK(fdp); 3707 if (error) 3708 break; 3709 } 3710 FILEDESC_SUNLOCK(fdp); 3711 fddrop(fdp); 3712 free(kif, M_TEMP); 3713 free(okif, M_TEMP); 3714 return (0); 3715 } 3716 3717 static SYSCTL_NODE(_kern_proc, KERN_PROC_OFILEDESC, ofiledesc, 3718 CTLFLAG_RD|CTLFLAG_MPSAFE, sysctl_kern_proc_ofiledesc, 3719 "Process ofiledesc entries"); 3720 #endif /* COMPAT_FREEBSD7 */ 3721 3722 int 3723 vntype_to_kinfo(int vtype) 3724 { 3725 struct { 3726 int vtype; 3727 int kf_vtype; 3728 } vtypes_table[] = { 3729 { VBAD, KF_VTYPE_VBAD }, 3730 { VBLK, KF_VTYPE_VBLK }, 3731 { VCHR, KF_VTYPE_VCHR }, 3732 { VDIR, KF_VTYPE_VDIR }, 3733 { VFIFO, KF_VTYPE_VFIFO }, 3734 { VLNK, KF_VTYPE_VLNK }, 3735 { VNON, KF_VTYPE_VNON }, 3736 { VREG, KF_VTYPE_VREG }, 3737 { VSOCK, KF_VTYPE_VSOCK } 3738 }; 3739 unsigned int i; 3740 3741 /* 3742 * Perform vtype translation. 3743 */ 3744 for (i = 0; i < nitems(vtypes_table); i++) 3745 if (vtypes_table[i].vtype == vtype) 3746 return (vtypes_table[i].kf_vtype); 3747 3748 return (KF_VTYPE_UNKNOWN); 3749 } 3750 3751 static SYSCTL_NODE(_kern_proc, KERN_PROC_FILEDESC, filedesc, 3752 CTLFLAG_RD|CTLFLAG_MPSAFE, sysctl_kern_proc_filedesc, 3753 "Process filedesc entries"); 3754 3755 /* 3756 * Store a process current working directory information to sbuf. 3757 * 3758 * Takes a locked proc as argument, and returns with the proc unlocked. 3759 */ 3760 int 3761 kern_proc_cwd_out(struct proc *p, struct sbuf *sb, ssize_t maxlen) 3762 { 3763 struct filedesc *fdp; 3764 struct export_fd_buf *efbuf; 3765 int error; 3766 3767 PROC_LOCK_ASSERT(p, MA_OWNED); 3768 3769 fdp = fdhold(p); 3770 PROC_UNLOCK(p); 3771 if (fdp == NULL) 3772 return (EINVAL); 3773 3774 efbuf = malloc(sizeof(*efbuf), M_TEMP, M_WAITOK); 3775 efbuf->fdp = fdp; 3776 efbuf->sb = sb; 3777 efbuf->remainder = maxlen; 3778 3779 FILEDESC_SLOCK(fdp); 3780 if (fdp->fd_cdir == NULL) 3781 error = EINVAL; 3782 else { 3783 vref(fdp->fd_cdir); 3784 error = export_vnode_to_sb(fdp->fd_cdir, KF_FD_TYPE_CWD, 3785 FREAD, efbuf); 3786 } 3787 FILEDESC_SUNLOCK(fdp); 3788 fddrop(fdp); 3789 free(efbuf, M_TEMP); 3790 return (error); 3791 } 3792 3793 /* 3794 * Get per-process current working directory. 3795 */ 3796 static int 3797 sysctl_kern_proc_cwd(SYSCTL_HANDLER_ARGS) 3798 { 3799 struct sbuf sb; 3800 struct proc *p; 3801 ssize_t maxlen; 3802 int error, error2, *name; 3803 3804 name = (int *)arg1; 3805 3806 sbuf_new_for_sysctl(&sb, NULL, sizeof(struct kinfo_file), req); 3807 sbuf_clear_flags(&sb, SBUF_INCLUDENUL); 3808 error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p); 3809 if (error != 0) { 3810 sbuf_delete(&sb); 3811 return (error); 3812 } 3813 maxlen = req->oldptr != NULL ? req->oldlen : -1; 3814 error = kern_proc_cwd_out(p, &sb, maxlen); 3815 error2 = sbuf_finish(&sb); 3816 sbuf_delete(&sb); 3817 return (error != 0 ? error : error2); 3818 } 3819 3820 static SYSCTL_NODE(_kern_proc, KERN_PROC_CWD, cwd, CTLFLAG_RD|CTLFLAG_MPSAFE, 3821 sysctl_kern_proc_cwd, "Process current working directory"); 3822 3823 #ifdef DDB 3824 /* 3825 * For the purposes of debugging, generate a human-readable string for the 3826 * file type. 3827 */ 3828 static const char * 3829 file_type_to_name(short type) 3830 { 3831 3832 switch (type) { 3833 case 0: 3834 return ("zero"); 3835 case DTYPE_VNODE: 3836 return ("vnod"); 3837 case DTYPE_SOCKET: 3838 return ("sock"); 3839 case DTYPE_PIPE: 3840 return ("pipe"); 3841 case DTYPE_FIFO: 3842 return ("fifo"); 3843 case DTYPE_KQUEUE: 3844 return ("kque"); 3845 case DTYPE_CRYPTO: 3846 return ("crpt"); 3847 case DTYPE_MQUEUE: 3848 return ("mque"); 3849 case DTYPE_SHM: 3850 return ("shm"); 3851 case DTYPE_SEM: 3852 return ("ksem"); 3853 default: 3854 return ("unkn"); 3855 } 3856 } 3857 3858 /* 3859 * For the purposes of debugging, identify a process (if any, perhaps one of 3860 * many) that references the passed file in its file descriptor array. Return 3861 * NULL if none. 3862 */ 3863 static struct proc * 3864 file_to_first_proc(struct file *fp) 3865 { 3866 struct filedesc *fdp; 3867 struct proc *p; 3868 int n; 3869 3870 FOREACH_PROC_IN_SYSTEM(p) { 3871 if (p->p_state == PRS_NEW) 3872 continue; 3873 fdp = p->p_fd; 3874 if (fdp == NULL) 3875 continue; 3876 for (n = 0; n <= fdp->fd_lastfile; n++) { 3877 if (fp == fdp->fd_ofiles[n].fde_file) 3878 return (p); 3879 } 3880 } 3881 return (NULL); 3882 } 3883 3884 static void 3885 db_print_file(struct file *fp, int header) 3886 { 3887 struct proc *p; 3888 3889 if (header) 3890 db_printf("%8s %4s %8s %8s %4s %5s %6s %8s %5s %12s\n", 3891 "File", "Type", "Data", "Flag", "GCFl", "Count", 3892 "MCount", "Vnode", "FPID", "FCmd"); 3893 p = file_to_first_proc(fp); 3894 db_printf("%8p %4s %8p %08x %04x %5d %6d %8p %5d %12s\n", fp, 3895 file_type_to_name(fp->f_type), fp->f_data, fp->f_flag, 3896 0, fp->f_count, 0, fp->f_vnode, 3897 p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-"); 3898 } 3899 3900 DB_SHOW_COMMAND(file, db_show_file) 3901 { 3902 struct file *fp; 3903 3904 if (!have_addr) { 3905 db_printf("usage: show file <addr>\n"); 3906 return; 3907 } 3908 fp = (struct file *)addr; 3909 db_print_file(fp, 1); 3910 } 3911 3912 DB_SHOW_COMMAND(files, db_show_files) 3913 { 3914 struct filedesc *fdp; 3915 struct file *fp; 3916 struct proc *p; 3917 int header; 3918 int n; 3919 3920 header = 1; 3921 FOREACH_PROC_IN_SYSTEM(p) { 3922 if (p->p_state == PRS_NEW) 3923 continue; 3924 if ((fdp = p->p_fd) == NULL) 3925 continue; 3926 for (n = 0; n <= fdp->fd_lastfile; ++n) { 3927 if ((fp = fdp->fd_ofiles[n].fde_file) == NULL) 3928 continue; 3929 db_print_file(fp, header); 3930 header = 0; 3931 } 3932 } 3933 } 3934 #endif 3935 3936 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 3937 &maxfilesperproc, 0, "Maximum files allowed open per process"); 3938 3939 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 3940 &maxfiles, 0, "Maximum number of files"); 3941 3942 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 3943 __DEVOLATILE(int *, &openfiles), 0, "System-wide number of open files"); 3944 3945 /* ARGSUSED*/ 3946 static void 3947 filelistinit(void *dummy) 3948 { 3949 3950 file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL, 3951 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 3952 filedesc0_zone = uma_zcreate("filedesc0", sizeof(struct filedesc0), 3953 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 3954 mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF); 3955 } 3956 SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL); 3957 3958 /*-------------------------------------------------------------------*/ 3959 3960 static int 3961 badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred, 3962 int flags, struct thread *td) 3963 { 3964 3965 return (EBADF); 3966 } 3967 3968 static int 3969 badfo_truncate(struct file *fp, off_t length, struct ucred *active_cred, 3970 struct thread *td) 3971 { 3972 3973 return (EINVAL); 3974 } 3975 3976 static int 3977 badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 3978 struct thread *td) 3979 { 3980 3981 return (EBADF); 3982 } 3983 3984 static int 3985 badfo_poll(struct file *fp, int events, struct ucred *active_cred, 3986 struct thread *td) 3987 { 3988 3989 return (0); 3990 } 3991 3992 static int 3993 badfo_kqfilter(struct file *fp, struct knote *kn) 3994 { 3995 3996 return (EBADF); 3997 } 3998 3999 static int 4000 badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 4001 struct thread *td) 4002 { 4003 4004 return (EBADF); 4005 } 4006 4007 static int 4008 badfo_close(struct file *fp, struct thread *td) 4009 { 4010 4011 return (0); 4012 } 4013 4014 static int 4015 badfo_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 4016 struct thread *td) 4017 { 4018 4019 return (EBADF); 4020 } 4021 4022 static int 4023 badfo_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 4024 struct thread *td) 4025 { 4026 4027 return (EBADF); 4028 } 4029 4030 static int 4031 badfo_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio, 4032 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags, 4033 struct thread *td) 4034 { 4035 4036 return (EBADF); 4037 } 4038 4039 static int 4040 badfo_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 4041 { 4042 4043 return (0); 4044 } 4045 4046 struct fileops badfileops = { 4047 .fo_read = badfo_readwrite, 4048 .fo_write = badfo_readwrite, 4049 .fo_truncate = badfo_truncate, 4050 .fo_ioctl = badfo_ioctl, 4051 .fo_poll = badfo_poll, 4052 .fo_kqfilter = badfo_kqfilter, 4053 .fo_stat = badfo_stat, 4054 .fo_close = badfo_close, 4055 .fo_chmod = badfo_chmod, 4056 .fo_chown = badfo_chown, 4057 .fo_sendfile = badfo_sendfile, 4058 .fo_fill_kinfo = badfo_fill_kinfo, 4059 }; 4060 4061 int 4062 invfo_rdwr(struct file *fp, struct uio *uio, struct ucred *active_cred, 4063 int flags, struct thread *td) 4064 { 4065 4066 return (EOPNOTSUPP); 4067 } 4068 4069 int 4070 invfo_truncate(struct file *fp, off_t length, struct ucred *active_cred, 4071 struct thread *td) 4072 { 4073 4074 return (EINVAL); 4075 } 4076 4077 int 4078 invfo_ioctl(struct file *fp, u_long com, void *data, 4079 struct ucred *active_cred, struct thread *td) 4080 { 4081 4082 return (ENOTTY); 4083 } 4084 4085 int 4086 invfo_poll(struct file *fp, int events, struct ucred *active_cred, 4087 struct thread *td) 4088 { 4089 4090 return (poll_no_poll(events)); 4091 } 4092 4093 int 4094 invfo_kqfilter(struct file *fp, struct knote *kn) 4095 { 4096 4097 return (EINVAL); 4098 } 4099 4100 int 4101 invfo_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 4102 struct thread *td) 4103 { 4104 4105 return (EINVAL); 4106 } 4107 4108 int 4109 invfo_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 4110 struct thread *td) 4111 { 4112 4113 return (EINVAL); 4114 } 4115 4116 int 4117 invfo_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio, 4118 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags, 4119 struct thread *td) 4120 { 4121 4122 return (EINVAL); 4123 } 4124 4125 /*-------------------------------------------------------------------*/ 4126 4127 /* 4128 * File Descriptor pseudo-device driver (/dev/fd/). 4129 * 4130 * Opening minor device N dup()s the file (if any) connected to file 4131 * descriptor N belonging to the calling process. Note that this driver 4132 * consists of only the ``open()'' routine, because all subsequent 4133 * references to this file will be direct to the other driver. 4134 * 4135 * XXX: we could give this one a cloning event handler if necessary. 4136 */ 4137 4138 /* ARGSUSED */ 4139 static int 4140 fdopen(struct cdev *dev, int mode, int type, struct thread *td) 4141 { 4142 4143 /* 4144 * XXX Kludge: set curthread->td_dupfd to contain the value of the 4145 * the file descriptor being sought for duplication. The error 4146 * return ensures that the vnode for this device will be released 4147 * by vn_open. Open will detect this special error and take the 4148 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN 4149 * will simply report the error. 4150 */ 4151 td->td_dupfd = dev2unit(dev); 4152 return (ENODEV); 4153 } 4154 4155 static struct cdevsw fildesc_cdevsw = { 4156 .d_version = D_VERSION, 4157 .d_open = fdopen, 4158 .d_name = "FD", 4159 }; 4160 4161 static void 4162 fildesc_drvinit(void *unused) 4163 { 4164 struct cdev *dev; 4165 4166 dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 0, NULL, 4167 UID_ROOT, GID_WHEEL, 0666, "fd/0"); 4168 make_dev_alias(dev, "stdin"); 4169 dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 1, NULL, 4170 UID_ROOT, GID_WHEEL, 0666, "fd/1"); 4171 make_dev_alias(dev, "stdout"); 4172 dev = make_dev_credf(MAKEDEV_ETERNAL, &fildesc_cdevsw, 2, NULL, 4173 UID_ROOT, GID_WHEEL, 0666, "fd/2"); 4174 make_dev_alias(dev, "stderr"); 4175 } 4176 4177 SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL); 4178