1 /* 2 * Copyright (c) 2005-2018 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Jeffrey Hsu and Matthew Dillon. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * 35 * Copyright (c) 1982, 1986, 1989, 1991, 1993 36 * The Regents of the University of California. All rights reserved. 37 * (c) UNIX System Laboratories, Inc. 38 * All or some portions of this file are derived from material licensed 39 * to the University of California by American Telephone and Telegraph 40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 41 * the permission of UNIX System Laboratories, Inc. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94 68 * $FreeBSD: src/sys/kern/kern_descrip.c,v 1.81.2.19 2004/02/28 00:43:31 tegge Exp $ 69 */ 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/malloc.h> 74 #include <sys/sysmsg.h> 75 #include <sys/conf.h> 76 #include <sys/device.h> 77 #include <sys/file.h> 78 #include <sys/filedesc.h> 79 #include <sys/kernel.h> 80 #include <sys/sysctl.h> 81 #include <sys/vnode.h> 82 #include <sys/proc.h> 83 #include <sys/nlookup.h> 84 #include <sys/stat.h> 85 #include <sys/filio.h> 86 #include <sys/fcntl.h> 87 #include <sys/unistd.h> 88 #include <sys/resourcevar.h> 89 #include <sys/event.h> 90 #include <sys/kern_syscall.h> 91 #include <sys/kcore.h> 92 #include <sys/kinfo.h> 93 #include <sys/un.h> 94 #include <sys/objcache.h> 95 96 #include <vm/vm.h> 97 #include <vm/vm_extern.h> 98 99 #include <sys/file2.h> 100 #include <sys/spinlock2.h> 101 102 static int fdalloc_locked(struct proc *p, struct filedesc *fdp, 103 int want, int *result); 104 static void fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd); 105 static void fdreserve_locked (struct filedesc *fdp, int fd0, int incr); 106 static struct file *funsetfd_locked (struct filedesc *fdp, int fd); 107 static void ffree(struct file *fp); 108 109 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); 110 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader", 111 "file desc to leader structures"); 112 static MALLOC_DEFINE_OBJ(M_FILE, sizeof(struct file), 113 "file", "Open file structure"); 114 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures"); 115 116 static struct krate krate_uidinfo = { .freq = 1 }; 117 118 static d_open_t fdopen; 119 #define NUMFDESC 64 120 121 #define CDEV_MAJOR 22 122 static struct dev_ops fildesc_ops = { 123 { "FD", 0, 0 }, 124 .d_open = fdopen, 125 }; 126 127 /* 128 * Descriptor management. 129 */ 130 #ifndef NFILELIST_HEADS 131 #define NFILELIST_HEADS 257 /* primary number */ 132 #endif 133 134 struct filelist_head { 135 struct spinlock spin; 136 struct filelist list; 137 } __cachealign; 138 139 static struct filelist_head filelist_heads[NFILELIST_HEADS]; 140 141 static int nfiles; /* actual number of open files */ 142 extern int cmask; 143 144 struct lwkt_token revoke_token = LWKT_TOKEN_INITIALIZER(revoke_token); 145 146 /* 147 * Fixup fd_freefile and fd_lastfile after a descriptor has been cleared. 148 * 149 * must be called with fdp->fd_spin exclusively held 150 */ 151 static __inline 152 void 153 fdfixup_locked(struct filedesc *fdp, int fd) 154 { 155 if (fd < fdp->fd_freefile) { 156 fdp->fd_freefile = fd; 157 } 158 while (fdp->fd_lastfile >= 0 && 159 fdp->fd_files[fdp->fd_lastfile].fp == NULL && 160 fdp->fd_files[fdp->fd_lastfile].reserved == 0 161 ) { 162 --fdp->fd_lastfile; 163 } 164 } 165 166 /* 167 * Clear the fd thread caches for this fdnode. 168 * 169 * If match_fdc is NULL, all thread caches of fdn will be cleared. 170 * The caller must hold fdp->fd_spin exclusively. The threads caching 171 * the descriptor do not have to be the current thread. The (status) 172 * argument is ignored. 173 * 174 * If match_fdc is not NULL, only the match_fdc's cache will be cleared. 175 * The caller must hold fdp->fd_spin shared and match_fdc must match a 176 * fdcache entry in curthread. match_fdc has been locked by the caller 177 * and had the specified (status). 178 * 179 * Since we are matching against a fp in the fdp (which must still be present 180 * at this time), fp will have at least two refs on any match and we can 181 * decrement the count trivially. 182 */ 183 static 184 void 185 fclearcache(struct fdnode *fdn, struct fdcache *match_fdc, int status) 186 { 187 struct fdcache *fdc; 188 struct file *fp; 189 int i; 190 191 /* 192 * match_fdc == NULL We are cleaning out all tdcache entries 193 * for the fdn and hold fdp->fd_spin exclusively. 194 * This can race against the target threads 195 * cleaning out specific entries. 196 * 197 * match_fdc != NULL We are cleaning out a specific tdcache 198 * entry on behalf of the owning thread 199 * and hold fdp->fd_spin shared. The thread 200 * has already locked the entry. This cannot 201 * race. 202 */ 203 fp = fdn->fp; 204 for (i = 0; i < NTDCACHEFD; ++i) { 205 if ((fdc = fdn->tdcache[i]) == NULL) 206 continue; 207 208 /* 209 * If match_fdc is non-NULL we are being asked to 210 * clear a specific fdc owned by curthread. There must 211 * be exactly one match. The caller has already locked 212 * the cache entry and will dispose of the lock after 213 * we return. 214 * 215 * Since we also have a shared lock on fdp, we 216 * can do this without atomic ops. 217 */ 218 if (match_fdc) { 219 if (fdc != match_fdc) 220 continue; 221 fdn->tdcache[i] = NULL; 222 KASSERT(fp == fdc->fp, 223 ("fclearcache(1): fp mismatch %p/%p\n", 224 fp, fdc->fp)); 225 fdc->fp = NULL; 226 fdc->fd = -1; 227 228 /* 229 * status can be 0 or 2. If 2 the ref is borrowed, 230 * if 0 the ref is not borrowed and we have to drop 231 * it. 232 */ 233 if (status == 0) 234 atomic_add_int(&fp->f_count, -1); 235 fdn->isfull = 0; /* heuristic */ 236 return; 237 } 238 239 /* 240 * Otherwise we hold an exclusive spin-lock and can only 241 * race thread consumers borrowing cache entries. 242 * 243 * Acquire the lock and dispose of the entry. We have to 244 * spin until we get the lock. 245 */ 246 for (;;) { 247 status = atomic_swap_int(&fdc->locked, 1); 248 if (status == 1) { /* foreign lock, retry */ 249 cpu_pause(); 250 continue; 251 } 252 fdn->tdcache[i] = NULL; 253 KASSERT(fp == fdc->fp, 254 ("fclearcache(2): fp mismatch %p/%p\n", 255 fp, fdc->fp)); 256 fdc->fp = NULL; 257 fdc->fd = -1; 258 if (status == 0) 259 atomic_add_int(&fp->f_count, -1); 260 fdn->isfull = 0; /* heuristic */ 261 atomic_swap_int(&fdc->locked, 0); 262 break; 263 } 264 } 265 KKASSERT(match_fdc == NULL); 266 } 267 268 /* 269 * Retrieve the fp for the specified fd given the specified file descriptor 270 * table. The fdp does not have to be owned by the current process. 271 * If flags != -1, fp->f_flag must contain at least one of the flags. 272 * 273 * This function is not able to cache the fp. 274 */ 275 struct file * 276 holdfp_fdp(struct filedesc *fdp, int fd, int flag) 277 { 278 struct file *fp; 279 280 spin_lock_shared(&fdp->fd_spin); 281 if (((u_int)fd) < fdp->fd_nfiles) { 282 fp = fdp->fd_files[fd].fp; /* can be NULL */ 283 if (fp) { 284 if ((fp->f_flag & flag) == 0 && flag != -1) { 285 fp = NULL; 286 } else { 287 fhold(fp); 288 } 289 } 290 } else { 291 fp = NULL; 292 } 293 spin_unlock_shared(&fdp->fd_spin); 294 295 return fp; 296 } 297 298 struct file * 299 holdfp_fdp_locked(struct filedesc *fdp, int fd, int flag) 300 { 301 struct file *fp; 302 303 if (((u_int)fd) < fdp->fd_nfiles) { 304 fp = fdp->fd_files[fd].fp; /* can be NULL */ 305 if (fp) { 306 if ((fp->f_flag & flag) == 0 && flag != -1) { 307 fp = NULL; 308 } else { 309 fhold(fp); 310 } 311 } 312 } else { 313 fp = NULL; 314 } 315 return fp; 316 } 317 318 /* 319 * Acquire the fp for the specified file descriptor, using the thread 320 * cache if possible and caching it if possible. 321 * 322 * td must be the curren thread. 323 */ 324 static 325 struct file * 326 _holdfp_cache(thread_t td, int fd) 327 { 328 struct filedesc *fdp; 329 struct fdcache *fdc; 330 struct fdcache *best; 331 struct fdnode *fdn; 332 struct file *fp; 333 int status; 334 int delta; 335 int i; 336 337 /* 338 * Fast 339 */ 340 for (fdc = &td->td_fdcache[0]; fdc < &td->td_fdcache[NFDCACHE]; ++fdc) { 341 if (fdc->fd != fd || fdc->fp == NULL) 342 continue; 343 status = atomic_swap_int(&fdc->locked, 1); 344 345 /* 346 * If someone else has locked our cache entry they are in 347 * the middle of clearing it, skip the entry. 348 */ 349 if (status == 1) 350 continue; 351 352 /* 353 * We have locked the entry, but if it no longer matches 354 * restore the previous state (0 or 2) and skip the entry. 355 */ 356 if (fdc->fd != fd || fdc->fp == NULL) { 357 atomic_swap_int(&fdc->locked, status); 358 continue; 359 } 360 361 /* 362 * We have locked a valid entry. We can borrow the ref 363 * for a mode 0 entry. We can get a valid fp for a mode 364 * 2 entry but not borrow the ref. 365 */ 366 if (status == 0) { 367 fp = fdc->fp; 368 fdc->lru = ++td->td_fdcache_lru; 369 atomic_swap_int(&fdc->locked, 2); 370 371 return fp; 372 } 373 if (status == 2) { 374 fp = fdc->fp; 375 fhold(fp); 376 fdc->lru = ++td->td_fdcache_lru; 377 atomic_swap_int(&fdc->locked, 2); 378 379 return fp; 380 } 381 KKASSERT(0); 382 } 383 384 /* 385 * Lookup the descriptor the slow way. This can contend against 386 * modifying operations in a multi-threaded environment and cause 387 * cache line ping ponging otherwise. 388 */ 389 fdp = td->td_proc->p_fd; 390 spin_lock_shared(&fdp->fd_spin); 391 392 if (((u_int)fd) < fdp->fd_nfiles) { 393 fp = fdp->fd_files[fd].fp; /* can be NULL */ 394 if (fp) { 395 fhold(fp); 396 if (fdp->fd_files[fd].isfull == 0) 397 goto enter; 398 } 399 } else { 400 fp = NULL; 401 } 402 spin_unlock_shared(&fdp->fd_spin); 403 404 return fp; 405 406 /* 407 * We found a valid fp and held it, fdp is still shared locked. 408 * Enter the fp into the per-thread cache. Find the oldest entry 409 * via lru, or an empty entry. 410 * 411 * Because fdp's spinlock is held (shared is fine), no other 412 * thread should be in the middle of clearing our selected entry. 413 */ 414 enter: 415 best = &td->td_fdcache[0]; 416 for (fdc = &td->td_fdcache[0]; fdc < &td->td_fdcache[NFDCACHE]; ++fdc) { 417 if (fdc->fp == NULL) { 418 best = fdc; 419 break; 420 } 421 delta = fdc->lru - best->lru; 422 if (delta < 0) 423 best = fdc; 424 } 425 426 /* 427 * Replace best 428 * 429 * Don't enter into the cache if we cannot get the lock. 430 */ 431 status = atomic_swap_int(&best->locked, 1); 432 if (status == 1) 433 goto done; 434 435 /* 436 * Clear the previous cache entry if present 437 */ 438 if (best->fp) { 439 KKASSERT(best->fd >= 0); 440 fclearcache(&fdp->fd_files[best->fd], best, status); 441 } 442 443 /* 444 * Create our new cache entry. This entry is 'safe' until we tie 445 * into the fdnode. If we cannot tie in, we will clear the entry. 446 */ 447 best->fd = fd; 448 best->fp = fp; 449 best->lru = ++td->td_fdcache_lru; 450 best->locked = 2; /* borrowed ref */ 451 452 fdn = &fdp->fd_files[fd]; 453 for (i = 0; i < NTDCACHEFD; ++i) { 454 if (fdn->tdcache[i] == NULL && 455 atomic_cmpset_ptr((void **)&fdn->tdcache[i], NULL, best)) { 456 goto done; 457 } 458 } 459 fdn->isfull = 1; /* no space */ 460 best->fd = -1; 461 best->fp = NULL; 462 best->locked = 0; 463 done: 464 spin_unlock_shared(&fdp->fd_spin); 465 466 return fp; 467 } 468 469 /* 470 * holdfp(), bypassing the cache in order to also be able to return 471 * the descriptor flags. A bit of a hack. 472 */ 473 static 474 struct file * 475 _holdfp2(thread_t td, int fd, char *fflagsp) 476 { 477 struct filedesc *fdp; 478 struct file *fp; 479 480 /* 481 * Lookup the descriptor the slow way. This can contend against 482 * modifying operations in a multi-threaded environment and cause 483 * cache line ping ponging otherwise. 484 */ 485 fdp = td->td_proc->p_fd; 486 spin_lock_shared(&fdp->fd_spin); 487 488 if (((u_int)fd) < fdp->fd_nfiles) { 489 fp = fdp->fd_files[fd].fp; /* can be NULL */ 490 if (fp) { 491 *fflagsp = fdp->fd_files[fd].fileflags; 492 fhold(fp); 493 } 494 } else { 495 fp = NULL; 496 } 497 spin_unlock_shared(&fdp->fd_spin); 498 499 return fp; 500 } 501 502 503 /* 504 * Drop the file pointer and return to the thread cache if possible. 505 * 506 * Caller must not hold fdp's spin lock. 507 * td must be the current thread. 508 */ 509 void 510 dropfp(thread_t td, int fd, struct file *fp) 511 { 512 struct filedesc *fdp; 513 struct fdcache *fdc; 514 int status; 515 516 fdp = td->td_proc->p_fd; 517 518 /* 519 * If our placeholder is still present we can re-cache the ref. 520 * 521 * Note that we can race an fclearcache(). 522 */ 523 for (fdc = &td->td_fdcache[0]; fdc < &td->td_fdcache[NFDCACHE]; ++fdc) { 524 if (fdc->fp != fp || fdc->fd != fd) 525 continue; 526 status = atomic_swap_int(&fdc->locked, 1); 527 switch(status) { 528 case 0: 529 /* 530 * Not in mode 2, fdrop fp without caching. 531 */ 532 atomic_swap_int(&fdc->locked, 0); 533 break; 534 case 1: 535 /* 536 * Not in mode 2, locked by someone else. 537 * fdrop fp without caching. 538 */ 539 break; 540 case 2: 541 /* 542 * Intact borrowed ref, return to mode 0 543 * indicating that we have returned the ref. 544 * 545 * Return the borrowed ref (2->1->0) 546 */ 547 if (fdc->fp == fp && fdc->fd == fd) { 548 atomic_swap_int(&fdc->locked, 0); 549 return; 550 } 551 atomic_swap_int(&fdc->locked, 2); 552 break; 553 } 554 } 555 556 /* 557 * Failed to re-cache, drop the fp without caching. 558 */ 559 fdrop(fp); 560 } 561 562 /* 563 * Clear all descriptors cached in the per-thread fd cache for 564 * the specified thread. 565 * 566 * Caller must not hold p_fd->spin. This function will temporarily 567 * obtain a shared spin lock. 568 */ 569 void 570 fexitcache(thread_t td) 571 { 572 struct filedesc *fdp; 573 struct fdcache *fdc; 574 int status; 575 int i; 576 577 if (td->td_proc == NULL) 578 return; 579 fdp = td->td_proc->p_fd; 580 if (fdp == NULL) 581 return; 582 583 /* 584 * A shared lock is sufficient as the caller controls td and we 585 * are only clearing td's cache. 586 */ 587 spin_lock_shared(&fdp->fd_spin); 588 for (i = 0; i < NFDCACHE; ++i) { 589 fdc = &td->td_fdcache[i]; 590 if (fdc->fp) { 591 status = atomic_swap_int(&fdc->locked, 1); 592 if (status == 1) { 593 cpu_pause(); 594 --i; 595 continue; 596 } 597 if (fdc->fp) { 598 KKASSERT(fdc->fd >= 0); 599 fclearcache(&fdp->fd_files[fdc->fd], fdc, 600 status); 601 } 602 atomic_swap_int(&fdc->locked, 0); 603 } 604 } 605 spin_unlock_shared(&fdp->fd_spin); 606 } 607 608 static __inline struct filelist_head * 609 fp2filelist(const struct file *fp) 610 { 611 u_int i; 612 613 i = (u_int)(uintptr_t)fp % NFILELIST_HEADS; 614 return &filelist_heads[i]; 615 } 616 617 static __inline 618 struct plimit * 619 readplimits(struct proc *p) 620 { 621 thread_t td = curthread; 622 struct plimit *limit; 623 624 limit = td->td_limit; 625 if (limit != p->p_limit) { 626 spin_lock_shared(&p->p_spin); 627 limit = p->p_limit; 628 atomic_add_int(&limit->p_refcnt, 1); 629 spin_unlock_shared(&p->p_spin); 630 if (td->td_limit) 631 plimit_free(td->td_limit); 632 td->td_limit = limit; 633 } 634 return limit; 635 } 636 637 /* 638 * System calls on descriptors. 639 */ 640 int 641 sys_getdtablesize(struct sysmsg *sysmsg, const struct getdtablesize_args *uap) 642 { 643 struct proc *p = curproc; 644 struct plimit *limit = readplimits(p); 645 int dtsize; 646 647 if (limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 648 dtsize = INT_MAX; 649 else 650 dtsize = (int)limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur; 651 652 if (dtsize > maxfilesperproc) 653 dtsize = maxfilesperproc; 654 if (dtsize < minfilesperproc) 655 dtsize = minfilesperproc; 656 if (p->p_ucred->cr_uid && dtsize > maxfilesperuser) 657 dtsize = maxfilesperuser; 658 sysmsg->sysmsg_result = dtsize; 659 return (0); 660 } 661 662 /* 663 * Duplicate a file descriptor to a particular value. 664 * 665 * note: keep in mind that a potential race condition exists when closing 666 * descriptors from a shared descriptor table (via rfork). 667 */ 668 int 669 sys_dup2(struct sysmsg *sysmsg, const struct dup2_args *uap) 670 { 671 int error; 672 int fd = 0; 673 674 error = kern_dup(DUP_FIXED, uap->from, uap->to, &fd); 675 sysmsg->sysmsg_fds[0] = fd; 676 677 return (error); 678 } 679 680 /* 681 * Duplicate a file descriptor. 682 */ 683 int 684 sys_dup(struct sysmsg *sysmsg, const struct dup_args *uap) 685 { 686 int error; 687 int fd = 0; 688 689 error = kern_dup(DUP_VARIABLE, uap->fd, 0, &fd); 690 sysmsg->sysmsg_fds[0] = fd; 691 692 return (error); 693 } 694 695 /* 696 * MPALMOSTSAFE - acquires mplock for fp operations 697 */ 698 int 699 kern_fcntl(int fd, int cmd, union fcntl_dat *dat, struct ucred *cred) 700 { 701 struct thread *td = curthread; 702 struct proc *p = td->td_proc; 703 struct file *fp; 704 struct vnode *vp; 705 u_int newmin; 706 u_int oflags; 707 u_int nflags; 708 int closedcounter; 709 int tmp, error, flg = F_POSIX; 710 711 KKASSERT(p); 712 713 /* 714 * Operations on file descriptors that do not require a file pointer. 715 */ 716 switch (cmd) { 717 case F_GETFD: 718 error = fgetfdflags(p->p_fd, fd, &tmp); 719 if (error == 0) 720 dat->fc_cloexec = (tmp & UF_EXCLOSE) ? FD_CLOEXEC : 0; 721 return (error); 722 723 case F_SETFD: 724 if (dat->fc_cloexec & FD_CLOEXEC) 725 error = fsetfdflags(p->p_fd, fd, UF_EXCLOSE); 726 else 727 error = fclrfdflags(p->p_fd, fd, UF_EXCLOSE); 728 return (error); 729 case F_DUPFD: 730 newmin = dat->fc_fd; 731 error = kern_dup(DUP_VARIABLE | DUP_FCNTL, fd, newmin, 732 &dat->fc_fd); 733 return (error); 734 case F_DUPFD_CLOEXEC: 735 newmin = dat->fc_fd; 736 error = kern_dup(DUP_VARIABLE | DUP_CLOEXEC | DUP_FCNTL, 737 fd, newmin, &dat->fc_fd); 738 return (error); 739 case F_DUP2FD: 740 newmin = dat->fc_fd; 741 error = kern_dup(DUP_FIXED, fd, newmin, &dat->fc_fd); 742 return (error); 743 case F_DUP2FD_CLOEXEC: 744 newmin = dat->fc_fd; 745 error = kern_dup(DUP_FIXED | DUP_CLOEXEC, fd, newmin, 746 &dat->fc_fd); 747 return (error); 748 default: 749 break; 750 } 751 752 /* 753 * Operations on file pointers 754 */ 755 closedcounter = p->p_fd->fd_closedcounter; 756 if ((fp = holdfp(td, fd, -1)) == NULL) 757 return (EBADF); 758 759 switch (cmd) { 760 case F_GETFL: 761 dat->fc_flags = OFLAGS(fp->f_flag); 762 error = 0; 763 break; 764 765 case F_SETFL: 766 oflags = fp->f_flag; 767 nflags = FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS; 768 nflags |= oflags & ~FCNTLFLAGS; 769 770 error = 0; 771 if (((nflags ^ oflags) & O_APPEND) && (oflags & FAPPENDONLY)) 772 error = EINVAL; 773 if (error == 0 && ((nflags ^ oflags) & FASYNC)) { 774 tmp = nflags & FASYNC; 775 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, 776 cred, NULL); 777 } 778 779 /* 780 * If no error, must be atomically set. 781 */ 782 while (error == 0) { 783 oflags = fp->f_flag; 784 cpu_ccfence(); 785 nflags = (oflags & ~FCNTLFLAGS) | (nflags & FCNTLFLAGS); 786 if (atomic_cmpset_int(&fp->f_flag, oflags, nflags)) 787 break; 788 cpu_pause(); 789 } 790 break; 791 792 case F_GETOWN: 793 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, 794 cred, NULL); 795 break; 796 797 case F_SETOWN: 798 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, 799 cred, NULL); 800 break; 801 802 case F_SETLKW: 803 flg |= F_WAIT; 804 /* Fall into F_SETLK */ 805 806 case F_SETLK: 807 if (fp->f_type != DTYPE_VNODE) { 808 error = EBADF; 809 break; 810 } 811 vp = (struct vnode *)fp->f_data; 812 813 /* 814 * copyin/lockop may block 815 */ 816 if (dat->fc_flock.l_whence == SEEK_CUR) 817 dat->fc_flock.l_start += fp->f_offset; 818 819 switch (dat->fc_flock.l_type) { 820 case F_RDLCK: 821 if ((fp->f_flag & FREAD) == 0) { 822 error = EBADF; 823 break; 824 } 825 if (p->p_leader->p_advlock_flag == 0) 826 p->p_leader->p_advlock_flag = 1; 827 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 828 &dat->fc_flock, flg); 829 break; 830 case F_WRLCK: 831 if ((fp->f_flag & FWRITE) == 0) { 832 error = EBADF; 833 break; 834 } 835 if (p->p_leader->p_advlock_flag == 0) 836 p->p_leader->p_advlock_flag = 1; 837 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK, 838 &dat->fc_flock, flg); 839 break; 840 case F_UNLCK: 841 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 842 &dat->fc_flock, F_POSIX); 843 break; 844 default: 845 error = EINVAL; 846 break; 847 } 848 849 /* 850 * It is possible to race a close() on the descriptor while 851 * we were blocked getting the lock. If this occurs the 852 * close might not have caught the lock. 853 */ 854 if (checkfdclosed(td, p->p_fd, fd, fp, closedcounter)) { 855 dat->fc_flock.l_whence = SEEK_SET; 856 dat->fc_flock.l_start = 0; 857 dat->fc_flock.l_len = 0; 858 dat->fc_flock.l_type = F_UNLCK; 859 VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 860 F_UNLCK, &dat->fc_flock, F_POSIX); 861 } 862 break; 863 864 case F_GETLK: 865 if (fp->f_type != DTYPE_VNODE) { 866 error = EBADF; 867 break; 868 } 869 vp = (struct vnode *)fp->f_data; 870 /* 871 * copyin/lockop may block 872 */ 873 if (dat->fc_flock.l_type != F_RDLCK && 874 dat->fc_flock.l_type != F_WRLCK && 875 dat->fc_flock.l_type != F_UNLCK) { 876 error = EINVAL; 877 break; 878 } 879 if (dat->fc_flock.l_whence == SEEK_CUR) 880 dat->fc_flock.l_start += fp->f_offset; 881 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, 882 &dat->fc_flock, F_POSIX); 883 break; 884 885 case F_GETPATH: 886 if (fp->f_type != DTYPE_VNODE) { 887 error = EBADF; 888 break; 889 } 890 891 /* 892 * cache_fullpath() itself is limited to MAXPATHLEN so we 893 * do not need an explicit length check, but we do have 894 * to munge the error to ERANGE as per fcntl.2 895 */ 896 error = cache_fullpath(p, &fp->f_nchandle, NULL, 897 &dat->fc_path.ptr, &dat->fc_path.buf, 1); 898 if (error == ENOMEM) 899 error = ERANGE; 900 break; 901 902 default: 903 error = EINVAL; 904 break; 905 } 906 907 fdrop(fp); 908 return (error); 909 } 910 911 /* 912 * The file control system call. 913 */ 914 int 915 sys_fcntl(struct sysmsg *sysmsg, const struct fcntl_args *uap) 916 { 917 union fcntl_dat dat; 918 int error; 919 920 switch (uap->cmd) { 921 case F_DUPFD: 922 case F_DUP2FD: 923 case F_DUPFD_CLOEXEC: 924 case F_DUP2FD_CLOEXEC: 925 dat.fc_fd = uap->arg; 926 break; 927 case F_SETFD: 928 dat.fc_cloexec = uap->arg; 929 break; 930 case F_SETFL: 931 dat.fc_flags = uap->arg; 932 break; 933 case F_SETOWN: 934 dat.fc_owner = uap->arg; 935 break; 936 case F_SETLKW: 937 case F_SETLK: 938 case F_GETLK: 939 error = copyin((caddr_t)uap->arg, &dat.fc_flock, 940 sizeof(struct flock)); 941 if (error) 942 return (error); 943 break; 944 } 945 946 error = kern_fcntl(uap->fd, uap->cmd, &dat, curthread->td_ucred); 947 948 if (error == 0) { 949 switch (uap->cmd) { 950 case F_DUPFD: 951 case F_DUP2FD: 952 case F_DUPFD_CLOEXEC: 953 case F_DUP2FD_CLOEXEC: 954 sysmsg->sysmsg_result = dat.fc_fd; 955 break; 956 case F_GETFD: 957 sysmsg->sysmsg_result = dat.fc_cloexec; 958 break; 959 case F_GETFL: 960 sysmsg->sysmsg_result = dat.fc_flags; 961 break; 962 case F_GETOWN: 963 sysmsg->sysmsg_result = dat.fc_owner; 964 break; 965 case F_GETLK: 966 error = copyout(&dat.fc_flock, (caddr_t)uap->arg, 967 sizeof(struct flock)); 968 break; 969 case F_GETPATH: 970 error = copyout(dat.fc_path.ptr, (caddr_t)uap->arg, 971 strlen(dat.fc_path.ptr) + 1); 972 kfree(dat.fc_path.buf, M_TEMP); 973 break; 974 } 975 } 976 977 return (error); 978 } 979 980 /* 981 * Common code for dup, dup2, and fcntl(F_DUPFD). 982 * 983 * There are four type flags: DUP_FCNTL, DUP_FIXED, DUP_VARIABLE, and 984 * DUP_CLOEXEC. 985 * 986 * DUP_FCNTL is for handling EINVAL vs. EBADF differences between 987 * fcntl()'s F_DUPFD and F_DUPFD_CLOEXEC and dup2() (per POSIX). 988 * The next two flags are mutually exclusive, and the fourth is optional. 989 * DUP_FIXED tells kern_dup() to destructively dup over an existing file 990 * descriptor if "new" is already open. DUP_VARIABLE tells kern_dup() 991 * to find the lowest unused file descriptor that is greater than or 992 * equal to "new". DUP_CLOEXEC, which works with either of the first 993 * two flags, sets the close-on-exec flag on the "new" file descriptor. 994 */ 995 int 996 kern_dup(int flags, int old, int new, int *res) 997 { 998 struct thread *td = curthread; 999 struct proc *p = td->td_proc; 1000 struct plimit *limit = readplimits(p); 1001 struct filedesc *fdp = p->p_fd; 1002 struct file *fp; 1003 struct file *delfp; 1004 int oldflags; 1005 int holdleaders; 1006 int dtsize; 1007 int error, newfd; 1008 1009 /* 1010 * Verify that we have a valid descriptor to dup from and 1011 * possibly to dup to. When the new descriptor is out of 1012 * bounds, fcntl()'s F_DUPFD and F_DUPFD_CLOEXEC must 1013 * return EINVAL, while dup2() returns EBADF in 1014 * this case. 1015 * 1016 * NOTE: maxfilesperuser is not applicable to dup() 1017 */ 1018 retry: 1019 if (limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1020 dtsize = INT_MAX; 1021 else 1022 dtsize = (int)limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur; 1023 if (dtsize > maxfilesperproc) 1024 dtsize = maxfilesperproc; 1025 if (dtsize < minfilesperproc) 1026 dtsize = minfilesperproc; 1027 1028 if (new < 0 || new >= dtsize) 1029 return (flags & DUP_FCNTL ? EINVAL : EBADF); 1030 1031 spin_lock(&fdp->fd_spin); 1032 if ((unsigned)old >= fdp->fd_nfiles || fdp->fd_files[old].fp == NULL) { 1033 spin_unlock(&fdp->fd_spin); 1034 return (EBADF); 1035 } 1036 if ((flags & DUP_FIXED) && old == new) { 1037 *res = new; 1038 if (flags & DUP_CLOEXEC) 1039 fdp->fd_files[new].fileflags |= UF_EXCLOSE; 1040 spin_unlock(&fdp->fd_spin); 1041 return (0); 1042 } 1043 fp = fdp->fd_files[old].fp; 1044 oldflags = fdp->fd_files[old].fileflags; 1045 fhold(fp); 1046 1047 /* 1048 * Allocate a new descriptor if DUP_VARIABLE, or expand the table 1049 * if the requested descriptor is beyond the current table size. 1050 * 1051 * This can block. Retry if the source descriptor no longer matches 1052 * or if our expectation in the expansion case races. 1053 * 1054 * If we are not expanding or allocating a new decriptor, then reset 1055 * the target descriptor to a reserved state so we have a uniform 1056 * setup for the next code block. 1057 */ 1058 if ((flags & DUP_VARIABLE) || new >= fdp->fd_nfiles) { 1059 error = fdalloc_locked(p, fdp, new, &newfd); 1060 if (error) { 1061 spin_unlock(&fdp->fd_spin); 1062 fdrop(fp); 1063 return (error); 1064 } 1065 /* 1066 * Check for ripout 1067 */ 1068 if (old >= fdp->fd_nfiles || fdp->fd_files[old].fp != fp) { 1069 fsetfd_locked(fdp, NULL, newfd); 1070 spin_unlock(&fdp->fd_spin); 1071 fdrop(fp); 1072 goto retry; 1073 } 1074 /* 1075 * Check for expansion race 1076 */ 1077 if ((flags & DUP_VARIABLE) == 0 && new != newfd) { 1078 fsetfd_locked(fdp, NULL, newfd); 1079 spin_unlock(&fdp->fd_spin); 1080 fdrop(fp); 1081 goto retry; 1082 } 1083 /* 1084 * Check for ripout, newfd reused old (this case probably 1085 * can't occur). 1086 */ 1087 if (old == newfd) { 1088 fsetfd_locked(fdp, NULL, newfd); 1089 spin_unlock(&fdp->fd_spin); 1090 fdrop(fp); 1091 goto retry; 1092 } 1093 new = newfd; 1094 delfp = NULL; 1095 } else { 1096 if (fdp->fd_files[new].reserved) { 1097 spin_unlock(&fdp->fd_spin); 1098 fdrop(fp); 1099 kprintf("Warning: dup(): target descriptor %d is " 1100 "reserved, waiting for it to be resolved\n", 1101 new); 1102 tsleep(fdp, 0, "fdres", hz); 1103 goto retry; 1104 } 1105 1106 /* 1107 * If the target descriptor was never allocated we have 1108 * to allocate it. If it was we have to clean out the 1109 * old descriptor. delfp inherits the ref from the 1110 * descriptor table. 1111 */ 1112 ++fdp->fd_closedcounter; 1113 fclearcache(&fdp->fd_files[new], NULL, 0); 1114 ++fdp->fd_closedcounter; 1115 delfp = fdp->fd_files[new].fp; 1116 fdp->fd_files[new].fp = NULL; 1117 fdp->fd_files[new].reserved = 1; 1118 if (delfp == NULL) { 1119 fdreserve_locked(fdp, new, 1); 1120 if (new > fdp->fd_lastfile) 1121 fdp->fd_lastfile = new; 1122 } 1123 1124 } 1125 1126 /* 1127 * NOTE: still holding an exclusive spinlock 1128 */ 1129 1130 /* 1131 * If a descriptor is being overwritten we may hve to tell 1132 * fdfree() to sleep to ensure that all relevant process 1133 * leaders can be traversed in closef(). 1134 */ 1135 if (delfp != NULL && p->p_fdtol != NULL) { 1136 fdp->fd_holdleaderscount++; 1137 holdleaders = 1; 1138 } else { 1139 holdleaders = 0; 1140 } 1141 KASSERT(delfp == NULL || (flags & DUP_FIXED), 1142 ("dup() picked an open file")); 1143 1144 /* 1145 * Duplicate the source descriptor, update lastfile. If the new 1146 * descriptor was not allocated and we aren't replacing an existing 1147 * descriptor we have to mark the descriptor as being in use. 1148 * 1149 * The fd_files[] array inherits fp's hold reference. 1150 */ 1151 fsetfd_locked(fdp, fp, new); 1152 if ((flags & DUP_CLOEXEC) != 0) 1153 fdp->fd_files[new].fileflags = oldflags | UF_EXCLOSE; 1154 else 1155 fdp->fd_files[new].fileflags = oldflags & ~UF_EXCLOSE; 1156 spin_unlock(&fdp->fd_spin); 1157 fdrop(fp); 1158 *res = new; 1159 1160 /* 1161 * If we dup'd over a valid file, we now own the reference to it 1162 * and must dispose of it using closef() semantics (as if a 1163 * close() were performed on it). 1164 */ 1165 if (delfp) { 1166 if (SLIST_FIRST(&delfp->f_klist)) 1167 knote_fdclose(delfp, fdp, new); 1168 closef(delfp, p); 1169 if (holdleaders) { 1170 spin_lock(&fdp->fd_spin); 1171 fdp->fd_holdleaderscount--; 1172 if (fdp->fd_holdleaderscount == 0 && 1173 fdp->fd_holdleaderswakeup != 0) { 1174 fdp->fd_holdleaderswakeup = 0; 1175 spin_unlock(&fdp->fd_spin); 1176 wakeup(&fdp->fd_holdleaderscount); 1177 } else { 1178 spin_unlock(&fdp->fd_spin); 1179 } 1180 } 1181 } 1182 return (0); 1183 } 1184 1185 /* 1186 * If sigio is on the list associated with a process or process group, 1187 * disable signalling from the device, remove sigio from the list and 1188 * free sigio. 1189 */ 1190 void 1191 funsetown(struct sigio **sigiop) 1192 { 1193 struct pgrp *pgrp; 1194 struct proc *p; 1195 struct sigio *sigio; 1196 1197 if ((sigio = *sigiop) != NULL) { 1198 lwkt_gettoken(&sigio_token); /* protect sigio */ 1199 KKASSERT(sigiop == sigio->sio_myref); 1200 sigio = *sigiop; 1201 *sigiop = NULL; 1202 lwkt_reltoken(&sigio_token); 1203 } 1204 if (sigio == NULL) 1205 return; 1206 1207 if (sigio->sio_pgid < 0) { 1208 pgrp = sigio->sio_pgrp; 1209 sigio->sio_pgrp = NULL; 1210 lwkt_gettoken(&pgrp->pg_token); 1211 SLIST_REMOVE(&pgrp->pg_sigiolst, sigio, sigio, sio_pgsigio); 1212 lwkt_reltoken(&pgrp->pg_token); 1213 pgrel(pgrp); 1214 } else /* if ((*sigiop)->sio_pgid > 0) */ { 1215 p = sigio->sio_proc; 1216 sigio->sio_proc = NULL; 1217 PHOLD(p); 1218 lwkt_gettoken(&p->p_token); 1219 SLIST_REMOVE(&p->p_sigiolst, sigio, sigio, sio_pgsigio); 1220 lwkt_reltoken(&p->p_token); 1221 PRELE(p); 1222 } 1223 crfree(sigio->sio_ucred); 1224 sigio->sio_ucred = NULL; 1225 kfree(sigio, M_SIGIO); 1226 } 1227 1228 /* 1229 * Free a list of sigio structures. Caller is responsible for ensuring 1230 * that the list is MPSAFE. 1231 */ 1232 void 1233 funsetownlst(struct sigiolst *sigiolst) 1234 { 1235 struct sigio *sigio; 1236 1237 while ((sigio = SLIST_FIRST(sigiolst)) != NULL) 1238 funsetown(sigio->sio_myref); 1239 } 1240 1241 /* 1242 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg). 1243 * 1244 * After permission checking, add a sigio structure to the sigio list for 1245 * the process or process group. 1246 */ 1247 int 1248 fsetown(pid_t pgid, struct sigio **sigiop) 1249 { 1250 struct proc *proc = NULL; 1251 struct pgrp *pgrp = NULL; 1252 struct sigio *sigio; 1253 int error; 1254 1255 if (pgid == 0) { 1256 funsetown(sigiop); 1257 return (0); 1258 } 1259 1260 if (pgid > 0) { 1261 proc = pfind(pgid); 1262 if (proc == NULL) { 1263 error = ESRCH; 1264 goto done; 1265 } 1266 1267 /* 1268 * Policy - Don't allow a process to FSETOWN a process 1269 * in another session. 1270 * 1271 * Remove this test to allow maximum flexibility or 1272 * restrict FSETOWN to the current process or process 1273 * group for maximum safety. 1274 */ 1275 if (proc->p_session != curproc->p_session) { 1276 error = EPERM; 1277 goto done; 1278 } 1279 } else /* if (pgid < 0) */ { 1280 pgrp = pgfind(-pgid); 1281 if (pgrp == NULL) { 1282 error = ESRCH; 1283 goto done; 1284 } 1285 1286 /* 1287 * Policy - Don't allow a process to FSETOWN a process 1288 * in another session. 1289 * 1290 * Remove this test to allow maximum flexibility or 1291 * restrict FSETOWN to the current process or process 1292 * group for maximum safety. 1293 */ 1294 if (pgrp->pg_session != curproc->p_session) { 1295 error = EPERM; 1296 goto done; 1297 } 1298 } 1299 sigio = kmalloc(sizeof(struct sigio), M_SIGIO, M_WAITOK | M_ZERO); 1300 if (pgid > 0) { 1301 KKASSERT(pgrp == NULL); 1302 lwkt_gettoken(&proc->p_token); 1303 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio); 1304 sigio->sio_proc = proc; 1305 lwkt_reltoken(&proc->p_token); 1306 } else { 1307 KKASSERT(proc == NULL); 1308 lwkt_gettoken(&pgrp->pg_token); 1309 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); 1310 sigio->sio_pgrp = pgrp; 1311 lwkt_reltoken(&pgrp->pg_token); 1312 pgrp = NULL; 1313 } 1314 sigio->sio_pgid = pgid; 1315 sigio->sio_ucred = crhold(curthread->td_ucred); 1316 /* It would be convenient if p_ruid was in ucred. */ 1317 sigio->sio_ruid = sigio->sio_ucred->cr_ruid; 1318 sigio->sio_myref = sigiop; 1319 1320 lwkt_gettoken(&sigio_token); 1321 while (*sigiop) 1322 funsetown(sigiop); 1323 *sigiop = sigio; 1324 lwkt_reltoken(&sigio_token); 1325 error = 0; 1326 done: 1327 if (pgrp) 1328 pgrel(pgrp); 1329 if (proc) 1330 PRELE(proc); 1331 return (error); 1332 } 1333 1334 /* 1335 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg). 1336 */ 1337 pid_t 1338 fgetown(struct sigio **sigiop) 1339 { 1340 struct sigio *sigio; 1341 pid_t own; 1342 1343 lwkt_gettoken_shared(&sigio_token); 1344 sigio = *sigiop; 1345 own = (sigio != NULL ? sigio->sio_pgid : 0); 1346 lwkt_reltoken(&sigio_token); 1347 1348 return (own); 1349 } 1350 1351 /* 1352 * Close many file descriptors. 1353 */ 1354 int 1355 sys_closefrom(struct sysmsg *sysmsg, const struct closefrom_args *uap) 1356 { 1357 return(kern_closefrom(uap->fd)); 1358 } 1359 1360 /* 1361 * Close all file descriptors greater then or equal to fd 1362 */ 1363 int 1364 kern_closefrom(int fd) 1365 { 1366 struct thread *td = curthread; 1367 struct proc *p = td->td_proc; 1368 struct filedesc *fdp; 1369 int error; 1370 int e2; 1371 1372 KKASSERT(p); 1373 fdp = p->p_fd; 1374 1375 if (fd < 0) 1376 return (EINVAL); 1377 1378 /* 1379 * NOTE: This function will skip unassociated descriptors and 1380 * reserved descriptors that have not yet been assigned. 1381 * fd_lastfile can change as a side effect of kern_close(). 1382 * 1383 * NOTE: We accumulate EINTR errors and return EINTR if any 1384 * close() returned EINTR. However, the descriptor is 1385 * still closed and we do not break out of the loop. 1386 */ 1387 error = 0; 1388 spin_lock(&fdp->fd_spin); 1389 while (fd <= fdp->fd_lastfile) { 1390 if (fdp->fd_files[fd].fp != NULL) { 1391 spin_unlock(&fdp->fd_spin); 1392 /* ok if this races another close */ 1393 e2 = kern_close(fd); 1394 if (e2 == EINTR) 1395 error = EINTR; 1396 spin_lock(&fdp->fd_spin); 1397 } 1398 ++fd; 1399 } 1400 spin_unlock(&fdp->fd_spin); 1401 1402 return error; 1403 } 1404 1405 /* 1406 * Close a file descriptor. 1407 */ 1408 int 1409 sys_close(struct sysmsg *sysmsg, const struct close_args *uap) 1410 { 1411 return(kern_close(uap->fd)); 1412 } 1413 1414 /* 1415 * close() helper 1416 */ 1417 int 1418 kern_close(int fd) 1419 { 1420 struct thread *td = curthread; 1421 struct proc *p = td->td_proc; 1422 struct filedesc *fdp; 1423 struct file *fp; 1424 int error; 1425 int holdleaders; 1426 1427 KKASSERT(p); 1428 fdp = p->p_fd; 1429 1430 /* 1431 * funsetfd*() also clears the fd cache 1432 */ 1433 spin_lock(&fdp->fd_spin); 1434 if ((fp = funsetfd_locked(fdp, fd)) == NULL) { 1435 spin_unlock(&fdp->fd_spin); 1436 return (EBADF); 1437 } 1438 holdleaders = 0; 1439 if (p->p_fdtol != NULL) { 1440 /* 1441 * Ask fdfree() to sleep to ensure that all relevant 1442 * process leaders can be traversed in closef(). 1443 */ 1444 fdp->fd_holdleaderscount++; 1445 holdleaders = 1; 1446 } 1447 1448 /* 1449 * we now hold the fp reference that used to be owned by the descriptor 1450 * array. 1451 */ 1452 spin_unlock(&fdp->fd_spin); 1453 if (SLIST_FIRST(&fp->f_klist)) 1454 knote_fdclose(fp, fdp, fd); 1455 error = closef(fp, p); 1456 if (holdleaders) { 1457 spin_lock(&fdp->fd_spin); 1458 fdp->fd_holdleaderscount--; 1459 if (fdp->fd_holdleaderscount == 0 && 1460 fdp->fd_holdleaderswakeup != 0) { 1461 fdp->fd_holdleaderswakeup = 0; 1462 spin_unlock(&fdp->fd_spin); 1463 wakeup(&fdp->fd_holdleaderscount); 1464 } else { 1465 spin_unlock(&fdp->fd_spin); 1466 } 1467 } 1468 return (error); 1469 } 1470 1471 /* 1472 * shutdown_args(int fd, int how) 1473 */ 1474 int 1475 kern_shutdown(int fd, int how) 1476 { 1477 struct thread *td = curthread; 1478 struct file *fp; 1479 int error; 1480 1481 if ((fp = holdfp(td, fd, -1)) == NULL) 1482 return (EBADF); 1483 error = fo_shutdown(fp, how); 1484 fdrop(fp); 1485 1486 return (error); 1487 } 1488 1489 /* 1490 * MPALMOSTSAFE 1491 */ 1492 int 1493 sys_shutdown(struct sysmsg *sysmsg, const struct shutdown_args *uap) 1494 { 1495 int error; 1496 1497 error = kern_shutdown(uap->s, uap->how); 1498 1499 return (error); 1500 } 1501 1502 /* 1503 * fstat() helper 1504 */ 1505 int 1506 kern_fstat(int fd, struct stat *ub) 1507 { 1508 struct thread *td = curthread; 1509 struct file *fp; 1510 int error; 1511 1512 if ((fp = holdfp(td, fd, -1)) == NULL) 1513 return (EBADF); 1514 error = fo_stat(fp, ub, td->td_ucred); 1515 fdrop(fp); 1516 1517 return (error); 1518 } 1519 1520 /* 1521 * Return status information about a file descriptor. 1522 */ 1523 int 1524 sys_fstat(struct sysmsg *sysmsg, const struct fstat_args *uap) 1525 { 1526 struct stat st; 1527 int error; 1528 1529 error = kern_fstat(uap->fd, &st); 1530 1531 if (error == 0) 1532 error = copyout(&st, uap->sb, sizeof(st)); 1533 return (error); 1534 } 1535 1536 /* 1537 * Return pathconf information about a file descriptor. 1538 * 1539 * MPALMOSTSAFE 1540 */ 1541 int 1542 sys_fpathconf(struct sysmsg *sysmsg, const struct fpathconf_args *uap) 1543 { 1544 struct thread *td = curthread; 1545 struct file *fp; 1546 struct vnode *vp; 1547 int error = 0; 1548 1549 if ((fp = holdfp(td, uap->fd, -1)) == NULL) 1550 return (EBADF); 1551 1552 switch (fp->f_type) { 1553 case DTYPE_PIPE: 1554 case DTYPE_SOCKET: 1555 if (uap->name != _PC_PIPE_BUF) { 1556 error = EINVAL; 1557 } else { 1558 sysmsg->sysmsg_result = PIPE_BUF; 1559 error = 0; 1560 } 1561 break; 1562 case DTYPE_FIFO: 1563 case DTYPE_VNODE: 1564 vp = (struct vnode *)fp->f_data; 1565 error = VOP_PATHCONF(vp, uap->name, &sysmsg->sysmsg_reg); 1566 break; 1567 default: 1568 error = EOPNOTSUPP; 1569 break; 1570 } 1571 fdrop(fp); 1572 return(error); 1573 } 1574 1575 /* 1576 * Grow the file table so it can hold through descriptor (want). 1577 * 1578 * The fdp's spinlock must be held exclusively on entry and may be held 1579 * exclusively on return. The spinlock may be cycled by the routine. 1580 */ 1581 static void 1582 fdgrow_locked(struct filedesc *fdp, int want) 1583 { 1584 struct fdnode *newfiles; 1585 struct fdnode *oldfiles; 1586 int nf, extra; 1587 1588 nf = fdp->fd_nfiles; 1589 do { 1590 /* nf has to be of the form 2^n - 1 */ 1591 nf = 2 * nf + 1; 1592 } while (nf <= want); 1593 1594 spin_unlock(&fdp->fd_spin); 1595 newfiles = kmalloc(nf * sizeof(struct fdnode), M_FILEDESC, M_WAITOK); 1596 spin_lock(&fdp->fd_spin); 1597 1598 /* 1599 * We could have raced another extend while we were not holding 1600 * the spinlock. 1601 */ 1602 if (fdp->fd_nfiles >= nf) { 1603 spin_unlock(&fdp->fd_spin); 1604 kfree(newfiles, M_FILEDESC); 1605 spin_lock(&fdp->fd_spin); 1606 return; 1607 } 1608 /* 1609 * Copy the existing ofile and ofileflags arrays 1610 * and zero the new portion of each array. 1611 */ 1612 extra = nf - fdp->fd_nfiles; 1613 bcopy(fdp->fd_files, newfiles, fdp->fd_nfiles * sizeof(struct fdnode)); 1614 bzero(&newfiles[fdp->fd_nfiles], extra * sizeof(struct fdnode)); 1615 1616 oldfiles = fdp->fd_files; 1617 fdp->fd_files = newfiles; 1618 fdp->fd_nfiles = nf; 1619 1620 if (oldfiles != fdp->fd_builtin_files) { 1621 spin_unlock(&fdp->fd_spin); 1622 kfree(oldfiles, M_FILEDESC); 1623 spin_lock(&fdp->fd_spin); 1624 } 1625 } 1626 1627 /* 1628 * Number of nodes in right subtree, including the root. 1629 */ 1630 static __inline int 1631 right_subtree_size(int n) 1632 { 1633 return (n ^ (n | (n + 1))); 1634 } 1635 1636 /* 1637 * Bigger ancestor. 1638 */ 1639 static __inline int 1640 right_ancestor(int n) 1641 { 1642 return (n | (n + 1)); 1643 } 1644 1645 /* 1646 * Smaller ancestor. 1647 */ 1648 static __inline int 1649 left_ancestor(int n) 1650 { 1651 return ((n & (n + 1)) - 1); 1652 } 1653 1654 /* 1655 * Traverse the in-place binary tree buttom-up adjusting the allocation 1656 * count so scans can determine where free descriptors are located. 1657 * 1658 * caller must be holding an exclusive spinlock on fdp 1659 */ 1660 static 1661 void 1662 fdreserve_locked(struct filedesc *fdp, int fd, int incr) 1663 { 1664 while (fd >= 0) { 1665 fdp->fd_files[fd].allocated += incr; 1666 KKASSERT(fdp->fd_files[fd].allocated >= 0); 1667 fd = left_ancestor(fd); 1668 } 1669 } 1670 1671 /* 1672 * Reserve a file descriptor for the process. If no error occurs, the 1673 * caller MUST at some point call fsetfd() or assign a file pointer 1674 * or dispose of the reservation. 1675 */ 1676 static 1677 int 1678 fdalloc_locked(struct proc *p, struct filedesc *fdp, int want, int *result) 1679 { 1680 struct plimit *limit = readplimits(p); 1681 struct uidinfo *uip; 1682 int fd, rsize, rsum, node, lim; 1683 1684 /* 1685 * Check dtable size limit 1686 */ 1687 *result = -1; /* avoid gcc warnings */ 1688 if (limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1689 lim = INT_MAX; 1690 else 1691 lim = (int)limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur; 1692 1693 if (lim > maxfilesperproc) 1694 lim = maxfilesperproc; 1695 if (lim < minfilesperproc) 1696 lim = minfilesperproc; 1697 if (want >= lim) 1698 return (EINVAL); 1699 1700 /* 1701 * Check that the user has not run out of descriptors (non-root only). 1702 * As a safety measure the dtable is allowed to have at least 1703 * minfilesperproc open fds regardless of the maxfilesperuser limit. 1704 * 1705 * This isn't as loose a spec as ui_posixlocks, so we use atomic 1706 * ops to force synchronize and recheck if we would otherwise 1707 * error. 1708 */ 1709 if (p->p_ucred->cr_uid && fdp->fd_nfiles >= minfilesperproc) { 1710 uip = p->p_ucred->cr_uidinfo; 1711 if (uip->ui_openfiles > maxfilesperuser) { 1712 int n; 1713 int count; 1714 1715 count = 0; 1716 for (n = 0; n < ncpus; ++n) { 1717 count += atomic_swap_int( 1718 &uip->ui_pcpu[n].pu_openfiles, 0); 1719 } 1720 atomic_add_int(&uip->ui_openfiles, count); 1721 if (uip->ui_openfiles > maxfilesperuser) { 1722 krateprintf(&krate_uidinfo, 1723 "Warning: user %d pid %d (%s) " 1724 "ran out of file descriptors " 1725 "(%d/%d)\n", 1726 p->p_ucred->cr_uid, (int)p->p_pid, 1727 p->p_comm, 1728 uip->ui_openfiles, maxfilesperuser); 1729 return(ENFILE); 1730 } 1731 } 1732 } 1733 1734 /* 1735 * Grow the dtable if necessary 1736 */ 1737 if (want >= fdp->fd_nfiles) 1738 fdgrow_locked(fdp, want); 1739 1740 /* 1741 * Search for a free descriptor starting at the higher 1742 * of want or fd_freefile. If that fails, consider 1743 * expanding the ofile array. 1744 * 1745 * NOTE! the 'allocated' field is a cumulative recursive allocation 1746 * count. If we happen to see a value of 0 then we can shortcut 1747 * our search. Otherwise we run through through the tree going 1748 * down branches we know have free descriptor(s) until we hit a 1749 * leaf node. The leaf node will be free but will not necessarily 1750 * have an allocated field of 0. 1751 */ 1752 retry: 1753 /* move up the tree looking for a subtree with a free node */ 1754 for (fd = max(want, fdp->fd_freefile); fd < min(fdp->fd_nfiles, lim); 1755 fd = right_ancestor(fd)) { 1756 if (fdp->fd_files[fd].allocated == 0) 1757 goto found; 1758 1759 rsize = right_subtree_size(fd); 1760 if (fdp->fd_files[fd].allocated == rsize) 1761 continue; /* right subtree full */ 1762 1763 /* 1764 * Free fd is in the right subtree of the tree rooted at fd. 1765 * Call that subtree R. Look for the smallest (leftmost) 1766 * subtree of R with an unallocated fd: continue moving 1767 * down the left branch until encountering a full left 1768 * subtree, then move to the right. 1769 */ 1770 for (rsum = 0, rsize /= 2; rsize > 0; rsize /= 2) { 1771 node = fd + rsize; 1772 rsum += fdp->fd_files[node].allocated; 1773 if (fdp->fd_files[fd].allocated == rsum + rsize) { 1774 fd = node; /* move to the right */ 1775 if (fdp->fd_files[node].allocated == 0) 1776 goto found; 1777 rsum = 0; 1778 } 1779 } 1780 goto found; 1781 } 1782 1783 /* 1784 * No space in current array. Expand? 1785 */ 1786 if (fdp->fd_nfiles >= lim) { 1787 return (EMFILE); 1788 } 1789 fdgrow_locked(fdp, want); 1790 goto retry; 1791 1792 found: 1793 KKASSERT(fd < fdp->fd_nfiles); 1794 if (fd > fdp->fd_lastfile) 1795 fdp->fd_lastfile = fd; 1796 if (want <= fdp->fd_freefile) 1797 fdp->fd_freefile = fd; 1798 *result = fd; 1799 KKASSERT(fdp->fd_files[fd].fp == NULL); 1800 KKASSERT(fdp->fd_files[fd].reserved == 0); 1801 fdp->fd_files[fd].fileflags = 0; 1802 fdp->fd_files[fd].reserved = 1; 1803 fdreserve_locked(fdp, fd, 1); 1804 1805 return (0); 1806 } 1807 1808 int 1809 fdalloc(struct proc *p, int want, int *result) 1810 { 1811 struct filedesc *fdp = p->p_fd; 1812 int error; 1813 1814 spin_lock(&fdp->fd_spin); 1815 error = fdalloc_locked(p, fdp, want, result); 1816 spin_unlock(&fdp->fd_spin); 1817 1818 return error; 1819 } 1820 1821 /* 1822 * Check to see whether n user file descriptors 1823 * are available to the process p. 1824 */ 1825 int 1826 fdavail(struct proc *p, int n) 1827 { 1828 struct plimit *limit = readplimits(p); 1829 struct filedesc *fdp = p->p_fd; 1830 struct fdnode *fdnode; 1831 int i, lim, last; 1832 1833 if (limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur > INT_MAX) 1834 lim = INT_MAX; 1835 else 1836 lim = (int)limit->pl_rlimit[RLIMIT_NOFILE].rlim_cur; 1837 1838 if (lim > maxfilesperproc) 1839 lim = maxfilesperproc; 1840 if (lim < minfilesperproc) 1841 lim = minfilesperproc; 1842 1843 spin_lock(&fdp->fd_spin); 1844 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) { 1845 spin_unlock(&fdp->fd_spin); 1846 return (1); 1847 } 1848 last = min(fdp->fd_nfiles, lim); 1849 fdnode = &fdp->fd_files[fdp->fd_freefile]; 1850 for (i = last - fdp->fd_freefile; --i >= 0; ++fdnode) { 1851 if (fdnode->fp == NULL && --n <= 0) { 1852 spin_unlock(&fdp->fd_spin); 1853 return (1); 1854 } 1855 } 1856 spin_unlock(&fdp->fd_spin); 1857 return (0); 1858 } 1859 1860 /* 1861 * Revoke open descriptors referencing (f_data, f_type) 1862 * 1863 * Any revoke executed within a prison is only able to 1864 * revoke descriptors for processes within that prison. 1865 * 1866 * Returns 0 on success or an error code. 1867 */ 1868 struct fdrevoke_info { 1869 void *data; 1870 short type; 1871 short unused; 1872 int found; 1873 struct ucred *cred; 1874 struct file *nfp; 1875 }; 1876 1877 static int fdrevoke_check_callback(struct file *fp, void *vinfo); 1878 static int fdrevoke_proc_callback(struct proc *p, void *vinfo); 1879 1880 int 1881 fdrevoke(void *f_data, short f_type, struct ucred *cred) 1882 { 1883 struct fdrevoke_info info; 1884 int error; 1885 1886 bzero(&info, sizeof(info)); 1887 info.data = f_data; 1888 info.type = f_type; 1889 info.cred = cred; 1890 error = falloc(NULL, &info.nfp, NULL); 1891 if (error) 1892 return (error); 1893 1894 /* 1895 * Scan the file pointer table once. dups do not dup file pointers, 1896 * only descriptors, so there is no leak. Set FREVOKED on the fps 1897 * being revoked. 1898 * 1899 * Any fps sent over unix-domain sockets will be revoked by the 1900 * socket code checking for FREVOKED when the fps are externialized. 1901 * revoke_token is used to make sure that fps marked FREVOKED and 1902 * externalized will be picked up by the following allproc_scan(). 1903 */ 1904 lwkt_gettoken(&revoke_token); 1905 allfiles_scan_exclusive(fdrevoke_check_callback, &info); 1906 lwkt_reltoken(&revoke_token); 1907 1908 /* 1909 * If any fps were marked track down the related descriptors 1910 * and close them. Any dup()s at this point will notice 1911 * the FREVOKED already set in the fp and do the right thing. 1912 */ 1913 if (info.found) 1914 allproc_scan(fdrevoke_proc_callback, &info, 0); 1915 fdrop(info.nfp); 1916 return(0); 1917 } 1918 1919 /* 1920 * Locate matching file pointers directly. 1921 * 1922 * WARNING: allfiles_scan_exclusive() holds a spinlock through these calls! 1923 */ 1924 static int 1925 fdrevoke_check_callback(struct file *fp, void *vinfo) 1926 { 1927 struct fdrevoke_info *info = vinfo; 1928 1929 /* 1930 * File pointers already flagged for revokation are skipped. 1931 */ 1932 if (fp->f_flag & FREVOKED) 1933 return(0); 1934 1935 /* 1936 * If revoking from a prison file pointers created outside of 1937 * that prison, or file pointers without creds, cannot be revoked. 1938 */ 1939 if (info->cred->cr_prison && 1940 (fp->f_cred == NULL || 1941 info->cred->cr_prison != fp->f_cred->cr_prison)) { 1942 return(0); 1943 } 1944 1945 /* 1946 * If the file pointer matches then mark it for revocation. The 1947 * flag is currently only used by unp_revoke_gc(). 1948 * 1949 * info->found is a heuristic and can race in a SMP environment. 1950 */ 1951 if (info->data == fp->f_data && info->type == fp->f_type) { 1952 atomic_set_int(&fp->f_flag, FREVOKED); 1953 info->found = 1; 1954 } 1955 return(0); 1956 } 1957 1958 /* 1959 * Locate matching file pointers via process descriptor tables. 1960 */ 1961 static int 1962 fdrevoke_proc_callback(struct proc *p, void *vinfo) 1963 { 1964 struct fdrevoke_info *info = vinfo; 1965 struct filedesc *fdp; 1966 struct file *fp; 1967 int n; 1968 1969 if (p->p_stat == SIDL || p->p_stat == SZOMB) 1970 return(0); 1971 if (info->cred->cr_prison && 1972 info->cred->cr_prison != p->p_ucred->cr_prison) { 1973 return(0); 1974 } 1975 1976 /* 1977 * If the controlling terminal of the process matches the 1978 * vnode being revoked we clear the controlling terminal. 1979 * 1980 * The normal spec_close() may not catch this because it 1981 * uses curproc instead of p. 1982 */ 1983 if (p->p_session && info->type == DTYPE_VNODE && 1984 info->data == p->p_session->s_ttyvp) { 1985 p->p_session->s_ttyvp = NULL; 1986 vrele(info->data); 1987 } 1988 1989 /* 1990 * Softref the fdp to prevent it from being destroyed 1991 */ 1992 spin_lock(&p->p_spin); 1993 if ((fdp = p->p_fd) == NULL) { 1994 spin_unlock(&p->p_spin); 1995 return(0); 1996 } 1997 atomic_add_int(&fdp->fd_softrefs, 1); 1998 spin_unlock(&p->p_spin); 1999 2000 /* 2001 * Locate and close any matching file descriptors, replacing 2002 * them with info->nfp. 2003 */ 2004 spin_lock(&fdp->fd_spin); 2005 for (n = 0; n < fdp->fd_nfiles; ++n) { 2006 if ((fp = fdp->fd_files[n].fp) == NULL) 2007 continue; 2008 if (fp->f_flag & FREVOKED) { 2009 ++fdp->fd_closedcounter; 2010 fclearcache(&fdp->fd_files[n], NULL, 0); 2011 ++fdp->fd_closedcounter; 2012 fhold(info->nfp); 2013 fdp->fd_files[n].fp = info->nfp; 2014 spin_unlock(&fdp->fd_spin); 2015 knote_fdclose(fp, fdp, n); /* XXX */ 2016 closef(fp, p); 2017 spin_lock(&fdp->fd_spin); 2018 } 2019 } 2020 spin_unlock(&fdp->fd_spin); 2021 atomic_subtract_int(&fdp->fd_softrefs, 1); 2022 return(0); 2023 } 2024 2025 /* 2026 * falloc: 2027 * Create a new open file structure and reserve a file decriptor 2028 * for the process that refers to it. 2029 * 2030 * Root creds are checked using lp, or assumed if lp is NULL. If 2031 * resultfd is non-NULL then lp must also be non-NULL. No file 2032 * descriptor is reserved (and no process context is needed) if 2033 * resultfd is NULL. 2034 * 2035 * A file pointer with a refcount of 1 is returned. Note that the 2036 * file pointer is NOT associated with the descriptor. If falloc 2037 * returns success, fsetfd() MUST be called to either associate the 2038 * file pointer or clear the reservation. 2039 */ 2040 int 2041 falloc(struct lwp *lp, struct file **resultfp, int *resultfd) 2042 { 2043 static struct timeval lastfail; 2044 static int curfail; 2045 struct filelist_head *head; 2046 struct file *fp; 2047 struct ucred *cred = lp ? lp->lwp_thread->td_ucred : proc0.p_ucred; 2048 int error; 2049 2050 fp = NULL; 2051 2052 /* 2053 * Handle filetable full issues and root overfill. 2054 */ 2055 if (nfiles >= maxfiles - maxfilesrootres && 2056 (cred->cr_ruid != 0 || nfiles >= maxfiles)) { 2057 if (ppsratecheck(&lastfail, &curfail, 1)) { 2058 kprintf("kern.maxfiles limit exceeded by uid %d, " 2059 "please see tuning(7).\n", 2060 cred->cr_ruid); 2061 } 2062 error = ENFILE; 2063 goto done; 2064 } 2065 2066 /* 2067 * Allocate a new file descriptor. 2068 */ 2069 fp = kmalloc_obj(sizeof(*fp), M_FILE, M_WAITOK|M_ZERO); 2070 spin_init(&fp->f_spin, "falloc"); 2071 SLIST_INIT(&fp->f_klist); 2072 fp->f_count = 1; 2073 fp->f_ops = &badfileops; 2074 fp->f_seqcount = 1; 2075 fsetcred(fp, cred); 2076 atomic_add_int(&nfiles, 1); 2077 2078 head = fp2filelist(fp); 2079 spin_lock(&head->spin); 2080 LIST_INSERT_HEAD(&head->list, fp, f_list); 2081 spin_unlock(&head->spin); 2082 2083 if (resultfd) { 2084 if ((error = fdalloc(lp->lwp_proc, 0, resultfd)) != 0) { 2085 fdrop(fp); 2086 fp = NULL; 2087 } 2088 } else { 2089 error = 0; 2090 } 2091 done: 2092 *resultfp = fp; 2093 return (error); 2094 } 2095 2096 /* 2097 * Check for races against a file descriptor by determining that the 2098 * file pointer is still associated with the specified file descriptor, 2099 * and a close is not currently in progress. 2100 */ 2101 int 2102 checkfdclosed(thread_t td, struct filedesc *fdp, int fd, struct file *fp, 2103 int closedcounter) 2104 { 2105 struct fdcache *fdc; 2106 int error; 2107 2108 cpu_lfence(); 2109 if (fdp->fd_closedcounter == closedcounter) 2110 return 0; 2111 2112 if (td->td_proc && td->td_proc->p_fd == fdp) { 2113 for (fdc = &td->td_fdcache[0]; 2114 fdc < &td->td_fdcache[NFDCACHE]; ++fdc) { 2115 if (fdc->fd == fd && fdc->fp == fp) 2116 return 0; 2117 } 2118 } 2119 2120 spin_lock_shared(&fdp->fd_spin); 2121 if ((unsigned)fd >= fdp->fd_nfiles || fp != fdp->fd_files[fd].fp) 2122 error = EBADF; 2123 else 2124 error = 0; 2125 spin_unlock_shared(&fdp->fd_spin); 2126 return (error); 2127 } 2128 2129 /* 2130 * Associate a file pointer with a previously reserved file descriptor. 2131 * This function always succeeds. 2132 * 2133 * If fp is NULL, the file descriptor is returned to the pool. 2134 * 2135 * Caller must hold an exclusive spinlock on fdp->fd_spin. 2136 */ 2137 static void 2138 fsetfd_locked(struct filedesc *fdp, struct file *fp, int fd) 2139 { 2140 KKASSERT((unsigned)fd < fdp->fd_nfiles); 2141 KKASSERT(fdp->fd_files[fd].reserved != 0); 2142 if (fp) { 2143 fhold(fp); 2144 /* fclearcache(&fdp->fd_files[fd], NULL, 0); */ 2145 fdp->fd_files[fd].fp = fp; 2146 fdp->fd_files[fd].reserved = 0; 2147 } else { 2148 fdp->fd_files[fd].reserved = 0; 2149 fdreserve_locked(fdp, fd, -1); 2150 fdfixup_locked(fdp, fd); 2151 } 2152 } 2153 2154 /* 2155 * Caller must hold an exclusive spinlock on fdp->fd_spin. 2156 */ 2157 void 2158 fsetfd(struct filedesc *fdp, struct file *fp, int fd) 2159 { 2160 spin_lock(&fdp->fd_spin); 2161 fsetfd_locked(fdp, fp, fd); 2162 spin_unlock(&fdp->fd_spin); 2163 } 2164 2165 /* 2166 * Caller must hold an exclusive spinlock on fdp->fd_spin. 2167 */ 2168 static 2169 struct file * 2170 funsetfd_locked(struct filedesc *fdp, int fd) 2171 { 2172 struct file *fp; 2173 2174 if ((unsigned)fd >= fdp->fd_nfiles) 2175 return (NULL); 2176 if ((fp = fdp->fd_files[fd].fp) == NULL) 2177 return (NULL); 2178 ++fdp->fd_closedcounter; 2179 fclearcache(&fdp->fd_files[fd], NULL, 0); 2180 fdp->fd_files[fd].fp = NULL; 2181 fdp->fd_files[fd].fileflags = 0; 2182 ++fdp->fd_closedcounter; 2183 2184 fdreserve_locked(fdp, fd, -1); 2185 fdfixup_locked(fdp, fd); 2186 2187 return(fp); 2188 } 2189 2190 /* 2191 * WARNING: May not be called before initial fsetfd(). 2192 */ 2193 int 2194 fgetfdflags(struct filedesc *fdp, int fd, int *flagsp) 2195 { 2196 int error; 2197 2198 spin_lock_shared(&fdp->fd_spin); 2199 if (((u_int)fd) >= fdp->fd_nfiles) { 2200 error = EBADF; 2201 } else if (fdp->fd_files[fd].fp == NULL) { 2202 error = EBADF; 2203 } else { 2204 *flagsp = fdp->fd_files[fd].fileflags; 2205 error = 0; 2206 } 2207 spin_unlock_shared(&fdp->fd_spin); 2208 2209 return (error); 2210 } 2211 2212 /* 2213 * WARNING: May not be called before initial fsetfd(). 2214 */ 2215 int 2216 fsetfdflags(struct filedesc *fdp, int fd, int add_flags) 2217 { 2218 int error; 2219 2220 spin_lock(&fdp->fd_spin); 2221 if (((u_int)fd) >= fdp->fd_nfiles) { 2222 error = EBADF; 2223 } else if (fdp->fd_files[fd].fp == NULL) { 2224 error = EBADF; 2225 } else { 2226 fdp->fd_files[fd].fileflags |= add_flags; 2227 error = 0; 2228 } 2229 spin_unlock(&fdp->fd_spin); 2230 2231 return (error); 2232 } 2233 2234 /* 2235 * WARNING: May not be called before initial fsetfd(). 2236 */ 2237 int 2238 fclrfdflags(struct filedesc *fdp, int fd, int rem_flags) 2239 { 2240 int error; 2241 2242 spin_lock(&fdp->fd_spin); 2243 if (((u_int)fd) >= fdp->fd_nfiles) { 2244 error = EBADF; 2245 } else if (fdp->fd_files[fd].fp == NULL) { 2246 error = EBADF; 2247 } else { 2248 fdp->fd_files[fd].fileflags &= ~rem_flags; 2249 error = 0; 2250 } 2251 spin_unlock(&fdp->fd_spin); 2252 2253 return (error); 2254 } 2255 2256 /* 2257 * Set/Change/Clear the creds for a fp and synchronize the uidinfo. 2258 */ 2259 void 2260 fsetcred(struct file *fp, struct ucred *ncr) 2261 { 2262 struct ucred *ocr; 2263 struct uidinfo *uip; 2264 struct uidcount *pup; 2265 int cpu = mycpuid; 2266 int count; 2267 2268 ocr = fp->f_cred; 2269 if (ocr == NULL || ncr == NULL || ocr->cr_uidinfo != ncr->cr_uidinfo) { 2270 if (ocr) { 2271 uip = ocr->cr_uidinfo; 2272 pup = &uip->ui_pcpu[cpu]; 2273 atomic_add_int(&pup->pu_openfiles, -1); 2274 if (pup->pu_openfiles < -PUP_LIMIT || 2275 pup->pu_openfiles > PUP_LIMIT) { 2276 count = atomic_swap_int(&pup->pu_openfiles, 0); 2277 atomic_add_int(&uip->ui_openfiles, count); 2278 } 2279 } 2280 if (ncr) { 2281 uip = ncr->cr_uidinfo; 2282 pup = &uip->ui_pcpu[cpu]; 2283 atomic_add_int(&pup->pu_openfiles, 1); 2284 if (pup->pu_openfiles < -PUP_LIMIT || 2285 pup->pu_openfiles > PUP_LIMIT) { 2286 count = atomic_swap_int(&pup->pu_openfiles, 0); 2287 atomic_add_int(&uip->ui_openfiles, count); 2288 } 2289 } 2290 } 2291 if (ncr) 2292 crhold(ncr); 2293 fp->f_cred = ncr; 2294 if (ocr) 2295 crfree(ocr); 2296 } 2297 2298 /* 2299 * Free a file descriptor. 2300 */ 2301 static 2302 void 2303 ffree(struct file *fp) 2304 { 2305 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!")); 2306 fsetcred(fp, NULL); 2307 if (fp->f_nchandle.ncp) 2308 cache_drop(&fp->f_nchandle); 2309 kfree_obj(fp, M_FILE); 2310 } 2311 2312 /* 2313 * called from init_main, initialize filedesc0 for proc0. 2314 */ 2315 void 2316 fdinit_bootstrap(struct proc *p0, struct filedesc *fdp0, int cmask) 2317 { 2318 p0->p_fd = fdp0; 2319 p0->p_fdtol = NULL; 2320 fdp0->fd_refcnt = 1; 2321 fdp0->fd_cmask = cmask; 2322 fdp0->fd_files = fdp0->fd_builtin_files; 2323 fdp0->fd_nfiles = NDFILE; 2324 fdp0->fd_lastfile = -1; 2325 spin_init(&fdp0->fd_spin, "fdinitbootstrap"); 2326 } 2327 2328 /* 2329 * Build a new filedesc structure. 2330 */ 2331 struct filedesc * 2332 fdinit(struct proc *p) 2333 { 2334 struct filedesc *newfdp; 2335 struct filedesc *fdp = p->p_fd; 2336 2337 newfdp = kmalloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK|M_ZERO); 2338 spin_lock(&fdp->fd_spin); 2339 if (fdp->fd_cdir) { 2340 newfdp->fd_cdir = fdp->fd_cdir; 2341 vref(newfdp->fd_cdir); 2342 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); 2343 } 2344 2345 /* 2346 * rdir may not be set in e.g. proc0 or anything vm_fork'd off of 2347 * proc0, but should unconditionally exist in other processes. 2348 */ 2349 if (fdp->fd_rdir) { 2350 newfdp->fd_rdir = fdp->fd_rdir; 2351 vref(newfdp->fd_rdir); 2352 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); 2353 } 2354 if (fdp->fd_jdir) { 2355 newfdp->fd_jdir = fdp->fd_jdir; 2356 vref(newfdp->fd_jdir); 2357 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); 2358 } 2359 spin_unlock(&fdp->fd_spin); 2360 2361 /* Create the file descriptor table. */ 2362 newfdp->fd_refcnt = 1; 2363 newfdp->fd_cmask = cmask; 2364 newfdp->fd_files = newfdp->fd_builtin_files; 2365 newfdp->fd_nfiles = NDFILE; 2366 newfdp->fd_lastfile = -1; 2367 spin_init(&newfdp->fd_spin, "fdinit"); 2368 2369 return (newfdp); 2370 } 2371 2372 /* 2373 * Share a filedesc structure. 2374 */ 2375 struct filedesc * 2376 fdshare(struct proc *p) 2377 { 2378 struct filedesc *fdp; 2379 2380 fdp = p->p_fd; 2381 spin_lock(&fdp->fd_spin); 2382 fdp->fd_refcnt++; 2383 spin_unlock(&fdp->fd_spin); 2384 return (fdp); 2385 } 2386 2387 /* 2388 * Copy a filedesc structure. 2389 */ 2390 int 2391 fdcopy(struct proc *p, struct filedesc **fpp) 2392 { 2393 struct filedesc *fdp = p->p_fd; 2394 struct filedesc *newfdp; 2395 struct fdnode *fdnode; 2396 int i; 2397 int ni; 2398 2399 /* 2400 * Certain daemons might not have file descriptors. 2401 */ 2402 if (fdp == NULL) 2403 return (0); 2404 2405 /* 2406 * Allocate the new filedesc and fd_files[] array. This can race 2407 * with operations by other threads on the fdp so we have to be 2408 * careful. 2409 */ 2410 newfdp = kmalloc(sizeof(struct filedesc), 2411 M_FILEDESC, M_WAITOK | M_ZERO | M_NULLOK); 2412 if (newfdp == NULL) { 2413 *fpp = NULL; 2414 return (-1); 2415 } 2416 again: 2417 spin_lock(&fdp->fd_spin); 2418 if (fdp->fd_lastfile < NDFILE) { 2419 newfdp->fd_files = newfdp->fd_builtin_files; 2420 i = NDFILE; 2421 } else { 2422 /* 2423 * We have to allocate (N^2-1) entries for our in-place 2424 * binary tree. Allow the table to shrink. 2425 */ 2426 i = fdp->fd_nfiles; 2427 ni = (i - 1) / 2; 2428 while (ni > fdp->fd_lastfile && ni > NDFILE) { 2429 i = ni; 2430 ni = (i - 1) / 2; 2431 } 2432 spin_unlock(&fdp->fd_spin); 2433 newfdp->fd_files = kmalloc(i * sizeof(struct fdnode), 2434 M_FILEDESC, M_WAITOK | M_ZERO); 2435 2436 /* 2437 * Check for race, retry 2438 */ 2439 spin_lock(&fdp->fd_spin); 2440 if (i <= fdp->fd_lastfile) { 2441 spin_unlock(&fdp->fd_spin); 2442 kfree(newfdp->fd_files, M_FILEDESC); 2443 goto again; 2444 } 2445 } 2446 2447 /* 2448 * Dup the remaining fields. vref() and cache_hold() can be 2449 * safely called while holding the read spinlock on fdp. 2450 * 2451 * The read spinlock on fdp is still being held. 2452 * 2453 * NOTE: vref and cache_hold calls for the case where the vnode 2454 * or cache entry already has at least one ref may be called 2455 * while holding spin locks. 2456 */ 2457 if ((newfdp->fd_cdir = fdp->fd_cdir) != NULL) { 2458 vref(newfdp->fd_cdir); 2459 cache_copy(&fdp->fd_ncdir, &newfdp->fd_ncdir); 2460 } 2461 /* 2462 * We must check for fd_rdir here, at least for now because 2463 * the init process is created before we have access to the 2464 * rootvode to take a reference to it. 2465 */ 2466 if ((newfdp->fd_rdir = fdp->fd_rdir) != NULL) { 2467 vref(newfdp->fd_rdir); 2468 cache_copy(&fdp->fd_nrdir, &newfdp->fd_nrdir); 2469 } 2470 if ((newfdp->fd_jdir = fdp->fd_jdir) != NULL) { 2471 vref(newfdp->fd_jdir); 2472 cache_copy(&fdp->fd_njdir, &newfdp->fd_njdir); 2473 } 2474 newfdp->fd_refcnt = 1; 2475 newfdp->fd_nfiles = i; 2476 newfdp->fd_lastfile = fdp->fd_lastfile; 2477 newfdp->fd_freefile = fdp->fd_freefile; 2478 newfdp->fd_cmask = fdp->fd_cmask; 2479 spin_init(&newfdp->fd_spin, "fdcopy"); 2480 2481 /* 2482 * Copy the descriptor table through (i). This also copies the 2483 * allocation state. Then go through and ref the file pointers 2484 * and clean up any KQ descriptors. 2485 * 2486 * kq descriptors cannot be copied. Since we haven't ref'd the 2487 * copied files yet we can ignore the return value from funsetfd(). 2488 * 2489 * The read spinlock on fdp is still being held. 2490 * 2491 * Be sure to clean out fdnode->tdcache, otherwise bad things will 2492 * happen. 2493 */ 2494 bcopy(fdp->fd_files, newfdp->fd_files, i * sizeof(struct fdnode)); 2495 for (i = 0 ; i < newfdp->fd_nfiles; ++i) { 2496 fdnode = &newfdp->fd_files[i]; 2497 if (fdnode->reserved) { 2498 fdreserve_locked(newfdp, i, -1); 2499 fdnode->reserved = 0; 2500 fdfixup_locked(newfdp, i); 2501 } else if (fdnode->fp) { 2502 bzero(&fdnode->tdcache, sizeof(fdnode->tdcache)); 2503 if (fdnode->fp->f_type == DTYPE_KQUEUE) { 2504 (void)funsetfd_locked(newfdp, i); 2505 } else { 2506 fhold(fdnode->fp); 2507 } 2508 } 2509 } 2510 spin_unlock(&fdp->fd_spin); 2511 *fpp = newfdp; 2512 return (0); 2513 } 2514 2515 /* 2516 * Release a filedesc structure. 2517 * 2518 * NOT MPSAFE (MPSAFE for refs > 1, but the final cleanup code is not MPSAFE) 2519 */ 2520 void 2521 fdfree(struct proc *p, struct filedesc *repl) 2522 { 2523 struct filedesc *fdp; 2524 struct fdnode *fdnode; 2525 int i; 2526 struct filedesc_to_leader *fdtol; 2527 struct file *fp; 2528 struct vnode *vp; 2529 struct flock lf; 2530 2531 /* 2532 * Before destroying or replacing p->p_fd we must be sure to 2533 * clean out the cache of the last thread, which should be 2534 * curthread. 2535 */ 2536 fexitcache(curthread); 2537 2538 /* 2539 * Certain daemons might not have file descriptors. 2540 */ 2541 fdp = p->p_fd; 2542 if (fdp == NULL) { 2543 p->p_fd = repl; 2544 return; 2545 } 2546 2547 /* 2548 * Severe messing around to follow. 2549 */ 2550 spin_lock(&fdp->fd_spin); 2551 2552 /* Check for special need to clear POSIX style locks */ 2553 fdtol = p->p_fdtol; 2554 if (fdtol != NULL) { 2555 KASSERT(fdtol->fdl_refcount > 0, 2556 ("filedesc_to_refcount botch: fdl_refcount=%d", 2557 fdtol->fdl_refcount)); 2558 if (fdtol->fdl_refcount == 1 && p->p_leader->p_advlock_flag) { 2559 for (i = 0; i <= fdp->fd_lastfile; ++i) { 2560 fdnode = &fdp->fd_files[i]; 2561 if (fdnode->fp == NULL || 2562 fdnode->fp->f_type != DTYPE_VNODE) { 2563 continue; 2564 } 2565 fp = fdnode->fp; 2566 fhold(fp); 2567 spin_unlock(&fdp->fd_spin); 2568 2569 lf.l_whence = SEEK_SET; 2570 lf.l_start = 0; 2571 lf.l_len = 0; 2572 lf.l_type = F_UNLCK; 2573 vp = (struct vnode *)fp->f_data; 2574 VOP_ADVLOCK(vp, (caddr_t)p->p_leader, 2575 F_UNLCK, &lf, F_POSIX); 2576 fdrop(fp); 2577 spin_lock(&fdp->fd_spin); 2578 } 2579 } 2580 retry: 2581 if (fdtol->fdl_refcount == 1) { 2582 if (fdp->fd_holdleaderscount > 0 && 2583 p->p_leader->p_advlock_flag) { 2584 /* 2585 * close() or do_dup() has cleared a reference 2586 * in a shared file descriptor table. 2587 */ 2588 fdp->fd_holdleaderswakeup = 1; 2589 ssleep(&fdp->fd_holdleaderscount, 2590 &fdp->fd_spin, 0, "fdlhold", 0); 2591 goto retry; 2592 } 2593 if (fdtol->fdl_holdcount > 0) { 2594 /* 2595 * Ensure that fdtol->fdl_leader 2596 * remains valid in closef(). 2597 */ 2598 fdtol->fdl_wakeup = 1; 2599 ssleep(fdtol, &fdp->fd_spin, 0, "fdlhold", 0); 2600 goto retry; 2601 } 2602 } 2603 fdtol->fdl_refcount--; 2604 if (fdtol->fdl_refcount == 0 && 2605 fdtol->fdl_holdcount == 0) { 2606 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev; 2607 fdtol->fdl_prev->fdl_next = fdtol->fdl_next; 2608 } else { 2609 fdtol = NULL; 2610 } 2611 p->p_fdtol = NULL; 2612 if (fdtol != NULL) { 2613 spin_unlock(&fdp->fd_spin); 2614 kfree(fdtol, M_FILEDESC_TO_LEADER); 2615 spin_lock(&fdp->fd_spin); 2616 } 2617 } 2618 if (--fdp->fd_refcnt > 0) { 2619 spin_unlock(&fdp->fd_spin); 2620 spin_lock(&p->p_spin); 2621 p->p_fd = repl; 2622 spin_unlock(&p->p_spin); 2623 return; 2624 } 2625 2626 /* 2627 * Even though we are the last reference to the structure allproc 2628 * scans may still reference the structure. Maintain proper 2629 * locks until we can replace p->p_fd. 2630 * 2631 * Also note that kqueue's closef still needs to reference the 2632 * fdp via p->p_fd, so we have to close the descriptors before 2633 * we replace p->p_fd. 2634 */ 2635 for (i = 0; i <= fdp->fd_lastfile; ++i) { 2636 if (fdp->fd_files[i].fp) { 2637 fp = funsetfd_locked(fdp, i); 2638 if (fp) { 2639 spin_unlock(&fdp->fd_spin); 2640 if (SLIST_FIRST(&fp->f_klist)) 2641 knote_fdclose(fp, fdp, i); 2642 closef(fp, p); 2643 spin_lock(&fdp->fd_spin); 2644 } 2645 } 2646 } 2647 spin_unlock(&fdp->fd_spin); 2648 2649 /* 2650 * Interlock against an allproc scan operations (typically frevoke). 2651 */ 2652 spin_lock(&p->p_spin); 2653 p->p_fd = repl; 2654 spin_unlock(&p->p_spin); 2655 2656 /* 2657 * Wait for any softrefs to go away. This race rarely occurs so 2658 * we can use a non-critical-path style poll/sleep loop. The 2659 * race only occurs against allproc scans. 2660 * 2661 * No new softrefs can occur with the fdp disconnected from the 2662 * process. 2663 */ 2664 if (fdp->fd_softrefs) { 2665 kprintf("pid %d: Warning, fdp race avoided\n", p->p_pid); 2666 while (fdp->fd_softrefs) 2667 tsleep(&fdp->fd_softrefs, 0, "fdsoft", 1); 2668 } 2669 2670 if (fdp->fd_files != fdp->fd_builtin_files) 2671 kfree(fdp->fd_files, M_FILEDESC); 2672 if (fdp->fd_cdir) { 2673 cache_drop(&fdp->fd_ncdir); 2674 vrele(fdp->fd_cdir); 2675 } 2676 if (fdp->fd_rdir) { 2677 cache_drop(&fdp->fd_nrdir); 2678 vrele(fdp->fd_rdir); 2679 } 2680 if (fdp->fd_jdir) { 2681 cache_drop(&fdp->fd_njdir); 2682 vrele(fdp->fd_jdir); 2683 } 2684 kfree(fdp, M_FILEDESC); 2685 } 2686 2687 /* 2688 * Retrieve and reference the file pointer associated with a descriptor. 2689 * 2690 * td must be the current thread. 2691 */ 2692 struct file * 2693 holdfp(thread_t td, int fd, int flag) 2694 { 2695 struct file *fp; 2696 2697 fp = _holdfp_cache(td, fd); 2698 if (fp) { 2699 if ((fp->f_flag & flag) == 0 && flag != -1) { 2700 fdrop(fp); 2701 fp = NULL; 2702 } 2703 } 2704 return fp; 2705 } 2706 2707 /* 2708 * holdsock() - load the struct file pointer associated 2709 * with a socket into *fpp. If an error occurs, non-zero 2710 * will be returned and *fpp will be set to NULL. 2711 * 2712 * td must be the current thread. 2713 */ 2714 int 2715 holdsock(thread_t td, int fd, struct file **fpp) 2716 { 2717 struct file *fp; 2718 int error; 2719 2720 /* 2721 * Lockless shortcut 2722 */ 2723 fp = _holdfp_cache(td, fd); 2724 if (fp) { 2725 if (fp->f_type != DTYPE_SOCKET) { 2726 fdrop(fp); 2727 fp = NULL; 2728 error = ENOTSOCK; 2729 } else { 2730 error = 0; 2731 } 2732 } else { 2733 error = EBADF; 2734 } 2735 *fpp = fp; 2736 2737 return (error); 2738 } 2739 2740 /* 2741 * Convert a user file descriptor to a held file pointer. 2742 * 2743 * td must be the current thread. 2744 */ 2745 int 2746 holdvnode(thread_t td, int fd, struct file **fpp) 2747 { 2748 struct file *fp; 2749 int error; 2750 2751 fp = _holdfp_cache(td, fd); 2752 if (fp) { 2753 if (fp->f_type != DTYPE_VNODE && fp->f_type != DTYPE_FIFO) { 2754 fdrop(fp); 2755 fp = NULL; 2756 error = EINVAL; 2757 } else { 2758 error = 0; 2759 } 2760 } else { 2761 error = EBADF; 2762 } 2763 *fpp = fp; 2764 2765 return (error); 2766 } 2767 2768 /* 2769 * Convert a user file descriptor to a held file pointer. 2770 * 2771 * td must be the current thread. 2772 */ 2773 int 2774 holdvnode2(thread_t td, int fd, struct file **fpp, char *fflagsp) 2775 { 2776 struct file *fp; 2777 int error; 2778 2779 fp = _holdfp2(td, fd, fflagsp); 2780 if (fp) { 2781 if (fp->f_type != DTYPE_VNODE && fp->f_type != DTYPE_FIFO) { 2782 fdrop(fp); 2783 fp = NULL; 2784 error = EINVAL; 2785 } else { 2786 error = 0; 2787 } 2788 } else { 2789 error = EBADF; 2790 } 2791 *fpp = fp; 2792 2793 return (error); 2794 } 2795 2796 /* 2797 * For setugid programs, we don't want to people to use that setugidness 2798 * to generate error messages which write to a file which otherwise would 2799 * otherwise be off-limits to the process. 2800 * 2801 * This is a gross hack to plug the hole. A better solution would involve 2802 * a special vop or other form of generalized access control mechanism. We 2803 * go ahead and just reject all procfs file systems accesses as dangerous. 2804 * 2805 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is 2806 * sufficient. We also don't for check setugidness since we know we are. 2807 */ 2808 static int 2809 is_unsafe(struct file *fp) 2810 { 2811 if (fp->f_type == DTYPE_VNODE && 2812 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS) 2813 return (1); 2814 return (0); 2815 } 2816 2817 /* 2818 * Make this setguid thing safe, if at all possible. 2819 * 2820 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() 2821 */ 2822 void 2823 setugidsafety(struct proc *p) 2824 { 2825 struct filedesc *fdp = p->p_fd; 2826 int i; 2827 2828 /* Certain daemons might not have file descriptors. */ 2829 if (fdp == NULL) 2830 return; 2831 2832 /* 2833 * note: fdp->fd_files may be reallocated out from under us while 2834 * we are blocked in a close. Be careful! 2835 */ 2836 for (i = 0; i <= fdp->fd_lastfile; i++) { 2837 if (i > 2) 2838 break; 2839 if (fdp->fd_files[i].fp && is_unsafe(fdp->fd_files[i].fp)) { 2840 struct file *fp; 2841 2842 /* 2843 * NULL-out descriptor prior to close to avoid 2844 * a race while close blocks. 2845 */ 2846 if ((fp = funsetfd_locked(fdp, i)) != NULL) { 2847 knote_fdclose(fp, fdp, i); 2848 closef(fp, p); 2849 } 2850 } 2851 } 2852 } 2853 2854 /* 2855 * Close all CLOEXEC files on exec. 2856 * 2857 * Only a single thread remains for the current process. 2858 * 2859 * NOT MPSAFE - scans fdp without spinlocks, calls knote_fdclose() 2860 */ 2861 void 2862 fdcloseexec(struct proc *p) 2863 { 2864 struct filedesc *fdp = p->p_fd; 2865 int i; 2866 2867 /* Certain daemons might not have file descriptors. */ 2868 if (fdp == NULL) 2869 return; 2870 2871 /* 2872 * We cannot cache fd_files since operations may block and rip 2873 * them out from under us. 2874 */ 2875 for (i = 0; i <= fdp->fd_lastfile; i++) { 2876 if (fdp->fd_files[i].fp != NULL && 2877 (fdp->fd_files[i].fileflags & UF_EXCLOSE)) { 2878 struct file *fp; 2879 2880 /* 2881 * NULL-out descriptor prior to close to avoid 2882 * a race while close blocks. 2883 * 2884 * (funsetfd*() also clears the fd cache) 2885 */ 2886 if ((fp = funsetfd_locked(fdp, i)) != NULL) { 2887 knote_fdclose(fp, fdp, i); 2888 closef(fp, p); 2889 } 2890 } 2891 } 2892 } 2893 2894 /* 2895 * It is unsafe for set[ug]id processes to be started with file 2896 * descriptors 0..2 closed, as these descriptors are given implicit 2897 * significance in the Standard C library. fdcheckstd() will create a 2898 * descriptor referencing /dev/null for each of stdin, stdout, and 2899 * stderr that is not already open. 2900 * 2901 * NOT MPSAFE - calls falloc, vn_open, etc 2902 */ 2903 int 2904 fdcheckstd(struct lwp *lp) 2905 { 2906 struct nlookupdata nd; 2907 struct filedesc *fdp; 2908 struct file *fp; 2909 int retval; 2910 int i, error, flags, devnull; 2911 2912 fdp = lp->lwp_proc->p_fd; 2913 if (fdp == NULL) 2914 return (0); 2915 devnull = -1; 2916 error = 0; 2917 for (i = 0; i < 3; i++) { 2918 if (fdp->fd_files[i].fp != NULL) 2919 continue; 2920 if (devnull < 0) { 2921 if ((error = falloc(lp, &fp, &devnull)) != 0) 2922 break; 2923 2924 error = nlookup_init(&nd, "/dev/null", UIO_SYSSPACE, 2925 NLC_FOLLOW|NLC_LOCKVP); 2926 flags = FREAD | FWRITE; 2927 if (error == 0) 2928 error = vn_open(&nd, &fp, flags, 0); 2929 if (error == 0) 2930 fsetfd(fdp, fp, devnull); 2931 else 2932 fsetfd(fdp, NULL, devnull); 2933 fdrop(fp); 2934 nlookup_done(&nd); 2935 if (error) 2936 break; 2937 KKASSERT(i == devnull); 2938 } else { 2939 error = kern_dup(DUP_FIXED, devnull, i, &retval); 2940 if (error != 0) 2941 break; 2942 } 2943 } 2944 return (error); 2945 } 2946 2947 /* 2948 * Internal form of close. 2949 * Decrement reference count on file structure. 2950 * Note: td and/or p may be NULL when closing a file 2951 * that was being passed in a message. 2952 * 2953 * MPALMOSTSAFE - acquires mplock for VOP operations 2954 */ 2955 int 2956 closef(struct file *fp, struct proc *p) 2957 { 2958 struct vnode *vp; 2959 struct flock lf; 2960 struct filedesc_to_leader *fdtol; 2961 2962 if (fp == NULL) 2963 return (0); 2964 2965 /* 2966 * POSIX record locking dictates that any close releases ALL 2967 * locks owned by this process. This is handled by setting 2968 * a flag in the unlock to free ONLY locks obeying POSIX 2969 * semantics, and not to free BSD-style file locks. 2970 * If the descriptor was in a message, POSIX-style locks 2971 * aren't passed with the descriptor. 2972 */ 2973 if (p != NULL && fp->f_type == DTYPE_VNODE && 2974 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) 2975 ) { 2976 if (p->p_leader->p_advlock_flag) { 2977 lf.l_whence = SEEK_SET; 2978 lf.l_start = 0; 2979 lf.l_len = 0; 2980 lf.l_type = F_UNLCK; 2981 vp = (struct vnode *)fp->f_data; 2982 VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK, 2983 &lf, F_POSIX); 2984 } 2985 fdtol = p->p_fdtol; 2986 if (fdtol != NULL) { 2987 lwkt_gettoken(&p->p_token); 2988 2989 /* 2990 * Handle special case where file descriptor table 2991 * is shared between multiple process leaders. 2992 */ 2993 for (fdtol = fdtol->fdl_next; 2994 fdtol != p->p_fdtol; 2995 fdtol = fdtol->fdl_next) { 2996 if (fdtol->fdl_leader->p_advlock_flag == 0) 2997 continue; 2998 fdtol->fdl_holdcount++; 2999 lf.l_whence = SEEK_SET; 3000 lf.l_start = 0; 3001 lf.l_len = 0; 3002 lf.l_type = F_UNLCK; 3003 vp = (struct vnode *)fp->f_data; 3004 VOP_ADVLOCK(vp, (caddr_t)fdtol->fdl_leader, 3005 F_UNLCK, &lf, F_POSIX); 3006 fdtol->fdl_holdcount--; 3007 if (fdtol->fdl_holdcount == 0 && 3008 fdtol->fdl_wakeup != 0) { 3009 fdtol->fdl_wakeup = 0; 3010 wakeup(fdtol); 3011 } 3012 } 3013 lwkt_reltoken(&p->p_token); 3014 } 3015 } 3016 return (fdrop(fp)); 3017 } 3018 3019 /* 3020 * fhold() can only be called if f_count is already at least 1 (i.e. the 3021 * caller of fhold() already has a reference to the file pointer in some 3022 * manner or other). 3023 * 3024 * Atomic ops are used for incrementing and decrementing f_count before 3025 * the 1->0 transition. f_count 1->0 transition is special, see the 3026 * comment in fdrop(). 3027 */ 3028 void 3029 fhold(struct file *fp) 3030 { 3031 /* 0->1 transition will never work */ 3032 KASSERT(fp->f_count > 0, ("fhold: invalid f_count %d", fp->f_count)); 3033 atomic_add_int(&fp->f_count, 1); 3034 } 3035 3036 /* 3037 * fdrop() - drop a reference to a descriptor 3038 */ 3039 int 3040 fdrop(struct file *fp) 3041 { 3042 struct flock lf; 3043 struct vnode *vp; 3044 int error, do_free = 0; 3045 3046 /* 3047 * NOTE: 3048 * Simple atomic_fetchadd_int(f_count, -1) here will cause use- 3049 * after-free or double free (due to f_count 0->1 transition), if 3050 * fhold() is called on the fps found through filehead iteration. 3051 */ 3052 for (;;) { 3053 int count = fp->f_count; 3054 3055 cpu_ccfence(); 3056 KASSERT(count > 0, ("fdrop: invalid f_count %d", count)); 3057 if (count == 1) { 3058 struct filelist_head *head = fp2filelist(fp); 3059 3060 /* 3061 * About to drop the last reference, hold the 3062 * filehead spin lock and drop it, so that no 3063 * one could see this fp through filehead anymore, 3064 * let alone fhold() this fp. 3065 */ 3066 spin_lock(&head->spin); 3067 if (atomic_cmpset_int(&fp->f_count, count, 0)) { 3068 LIST_REMOVE(fp, f_list); 3069 spin_unlock(&head->spin); 3070 atomic_subtract_int(&nfiles, 1); 3071 do_free = 1; /* free this fp */ 3072 break; 3073 } 3074 spin_unlock(&head->spin); 3075 /* retry */ 3076 } else if (atomic_cmpset_int(&fp->f_count, count, count - 1)) { 3077 break; 3078 } 3079 /* retry */ 3080 } 3081 if (!do_free) 3082 return (0); 3083 3084 KKASSERT(SLIST_FIRST(&fp->f_klist) == NULL); 3085 3086 /* 3087 * The last reference has gone away, we own the fp structure free 3088 * and clear. 3089 */ 3090 if (fp->f_count < 0) 3091 panic("fdrop: count < 0"); 3092 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE && 3093 (((struct vnode *)fp->f_data)->v_flag & VMAYHAVELOCKS) 3094 ) { 3095 lf.l_whence = SEEK_SET; 3096 lf.l_start = 0; 3097 lf.l_len = 0; 3098 lf.l_type = F_UNLCK; 3099 vp = (struct vnode *)fp->f_data; 3100 VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); 3101 } 3102 if (fp->f_ops != &badfileops) 3103 error = fo_close(fp); 3104 else 3105 error = 0; 3106 ffree(fp); 3107 return (error); 3108 } 3109 3110 /* 3111 * Apply an advisory lock on a file descriptor. 3112 * 3113 * Just attempt to get a record lock of the requested type on 3114 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). 3115 * 3116 * MPALMOSTSAFE 3117 */ 3118 int 3119 sys_flock(struct sysmsg *sysmsg, const struct flock_args *uap) 3120 { 3121 thread_t td = curthread; 3122 struct file *fp; 3123 struct vnode *vp; 3124 struct flock lf; 3125 int error; 3126 3127 if ((fp = holdfp(td, uap->fd, -1)) == NULL) 3128 return (EBADF); 3129 if (fp->f_type != DTYPE_VNODE) { 3130 error = EOPNOTSUPP; 3131 goto done; 3132 } 3133 vp = (struct vnode *)fp->f_data; 3134 lf.l_whence = SEEK_SET; 3135 lf.l_start = 0; 3136 lf.l_len = 0; 3137 if (uap->how & LOCK_UN) { 3138 lf.l_type = F_UNLCK; 3139 atomic_clear_int(&fp->f_flag, FHASLOCK); /* race ok */ 3140 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0); 3141 goto done; 3142 } 3143 if (uap->how & LOCK_EX) 3144 lf.l_type = F_WRLCK; 3145 else if (uap->how & LOCK_SH) 3146 lf.l_type = F_RDLCK; 3147 else { 3148 error = EBADF; 3149 goto done; 3150 } 3151 if (uap->how & LOCK_NB) 3152 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 0); 3153 else 3154 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_WAIT); 3155 atomic_set_int(&fp->f_flag, FHASLOCK); /* race ok */ 3156 done: 3157 fdrop(fp); 3158 return (error); 3159 } 3160 3161 /* 3162 * File Descriptor pseudo-device driver ( /dev/fd/N ). 3163 * 3164 * This interface is now a bit more linux-compatible and attempts to not 3165 * share seek positions by not sharing the fp of the descriptor when 3166 * possible. 3167 * 3168 * Probably a good idea anyhow, but now particularly important for 3169 * fexecve() which uses /dev/fd/N. 3170 * 3171 * The original interface effectively dup()d the descriptor. 3172 */ 3173 static int 3174 fdopen(struct dev_open_args *ap) 3175 { 3176 struct file *wfp; 3177 thread_t td; 3178 int error; 3179 int sfd; 3180 3181 td = curthread; 3182 KKASSERT(td->td_lwp != NULL); 3183 3184 /* 3185 * Get the fp for /dev/fd/N 3186 */ 3187 sfd = minor(ap->a_head.a_dev); 3188 if ((wfp = holdfp(td, sfd, -1)) == NULL) 3189 return (EBADF); 3190 3191 /* 3192 * Close a revoke/dup race. Duping a descriptor marked as revoked 3193 * will dup a dummy descriptor instead of the real one. 3194 */ 3195 if (wfp->f_flag & FREVOKED) { 3196 kprintf("Warning: attempt to dup() a revoked descriptor\n"); 3197 fdrop(wfp); 3198 wfp = NULL; 3199 error = falloc(NULL, &wfp, NULL); 3200 if (error) 3201 return (error); 3202 } 3203 3204 /* 3205 * Check that the mode the file is being opened for is a 3206 * subset of the mode of the existing descriptor. 3207 */ 3208 if (ap->a_fpp == NULL) { 3209 fdrop(wfp); 3210 return EINVAL; 3211 } 3212 if (((ap->a_oflags & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { 3213 fdrop(wfp); 3214 return EACCES; 3215 } 3216 if (wfp->f_type == DTYPE_VNODE && wfp->f_data) { 3217 /* 3218 * If wfp is a vnode create a new fp so things like the 3219 * seek position (etc) are not shared with the original. 3220 * 3221 * Don't try to call VOP_OPEN(). Adjust the open-count 3222 * ourselves. 3223 */ 3224 struct vnode *vp; 3225 struct file *fp; 3226 3227 vp = wfp->f_data; 3228 fp = *ap->a_fpp; 3229 3230 /* 3231 * Yah... this wouldn't be good. 3232 */ 3233 if ((ap->a_oflags & (FWRITE|O_TRUNC)) && vp->v_type == VDIR) { 3234 fdrop(wfp); 3235 return EISDIR; 3236 } 3237 3238 /* 3239 * Setup the new fp and simulate an open(), but for now do 3240 * not actually call VOP_OPEN() though we probably could. 3241 */ 3242 fp->f_type = DTYPE_VNODE; 3243 /* retain flags not to be copied */ 3244 fp->f_flag = (fp->f_flag & ~FMASK) | (ap->a_oflags & FMASK); 3245 fp->f_ops = &vnode_fileops; 3246 fp->f_data = vp; 3247 vref(vp); 3248 3249 if (ap->a_oflags & FWRITE) 3250 atomic_add_int(&vp->v_writecount, 1); 3251 KKASSERT(vp->v_opencount >= 0 && vp->v_opencount != INT_MAX); 3252 atomic_add_int(&vp->v_opencount, 1); 3253 fdrop(wfp); 3254 } else { 3255 /* 3256 * If wfp is not a vnode we have to share it directly. 3257 */ 3258 fdrop(*ap->a_fpp); 3259 *ap->a_fpp = wfp; /* transfer hold count */ 3260 } 3261 return EALREADY; 3262 } 3263 3264 /* 3265 * NOT MPSAFE - I think these refer to a common file descriptor table 3266 * and we need to spinlock that to link fdtol in. 3267 */ 3268 struct filedesc_to_leader * 3269 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 3270 struct proc *leader) 3271 { 3272 struct filedesc_to_leader *fdtol; 3273 3274 fdtol = kmalloc(sizeof(struct filedesc_to_leader), 3275 M_FILEDESC_TO_LEADER, M_WAITOK | M_ZERO); 3276 fdtol->fdl_refcount = 1; 3277 fdtol->fdl_holdcount = 0; 3278 fdtol->fdl_wakeup = 0; 3279 fdtol->fdl_leader = leader; 3280 if (old != NULL) { 3281 fdtol->fdl_next = old->fdl_next; 3282 fdtol->fdl_prev = old; 3283 old->fdl_next = fdtol; 3284 fdtol->fdl_next->fdl_prev = fdtol; 3285 } else { 3286 fdtol->fdl_next = fdtol; 3287 fdtol->fdl_prev = fdtol; 3288 } 3289 return fdtol; 3290 } 3291 3292 /* 3293 * Scan all file pointers in the system. The callback is made with 3294 * the master list spinlock held exclusively. 3295 */ 3296 void 3297 allfiles_scan_exclusive(int (*callback)(struct file *, void *), void *data) 3298 { 3299 int i; 3300 3301 for (i = 0; i < NFILELIST_HEADS; ++i) { 3302 struct filelist_head *head = &filelist_heads[i]; 3303 struct file *fp; 3304 3305 spin_lock(&head->spin); 3306 LIST_FOREACH(fp, &head->list, f_list) { 3307 int res; 3308 3309 res = callback(fp, data); 3310 if (res < 0) 3311 break; 3312 } 3313 spin_unlock(&head->spin); 3314 } 3315 } 3316 3317 /* 3318 * Get file structures. 3319 * 3320 * NOT MPSAFE - process list scan, SYSCTL_OUT (probably not mpsafe) 3321 */ 3322 3323 struct sysctl_kern_file_info { 3324 int count; 3325 int error; 3326 struct sysctl_req *req; 3327 }; 3328 3329 static int sysctl_kern_file_callback(struct proc *p, void *data); 3330 3331 static int 3332 sysctl_kern_file(SYSCTL_HANDLER_ARGS) 3333 { 3334 struct sysctl_kern_file_info info; 3335 3336 /* 3337 * Note: because the number of file descriptors is calculated 3338 * in different ways for sizing vs returning the data, 3339 * there is information leakage from the first loop. However, 3340 * it is of a similar order of magnitude to the leakage from 3341 * global system statistics such as kern.openfiles. 3342 * 3343 * When just doing a count, note that we cannot just count 3344 * the elements and add f_count via the filehead list because 3345 * threaded processes share their descriptor table and f_count might 3346 * still be '1' in that case. 3347 * 3348 * Since the SYSCTL op can block, we must hold the process to 3349 * prevent it being ripped out from under us either in the 3350 * file descriptor loop or in the greater LIST_FOREACH. The 3351 * process may be in varying states of disrepair. If the process 3352 * is in SZOMB we may have caught it just as it is being removed 3353 * from the allproc list, we must skip it in that case to maintain 3354 * an unbroken chain through the allproc list. 3355 */ 3356 info.count = 0; 3357 info.error = 0; 3358 info.req = req; 3359 allproc_scan(sysctl_kern_file_callback, &info, 0); 3360 3361 /* 3362 * When just calculating the size, overestimate a bit to try to 3363 * prevent system activity from causing the buffer-fill call 3364 * to fail later on. 3365 */ 3366 if (req->oldptr == NULL) { 3367 info.count = (info.count + 16) + (info.count / 10); 3368 info.error = SYSCTL_OUT(req, NULL, 3369 info.count * sizeof(struct kinfo_file)); 3370 } 3371 return (info.error); 3372 } 3373 3374 static int 3375 sysctl_kern_file_callback(struct proc *p, void *data) 3376 { 3377 struct sysctl_kern_file_info *info = data; 3378 struct kinfo_file kf; 3379 struct filedesc *fdp; 3380 struct file *fp; 3381 uid_t uid; 3382 int n; 3383 3384 if (p->p_stat == SIDL || p->p_stat == SZOMB) 3385 return(0); 3386 if (!(PRISON_CHECK(info->req->td->td_ucred, p->p_ucred) != 0)) 3387 return(0); 3388 3389 /* 3390 * Softref the fdp to prevent it from being destroyed 3391 */ 3392 spin_lock(&p->p_spin); 3393 if ((fdp = p->p_fd) == NULL) { 3394 spin_unlock(&p->p_spin); 3395 return(0); 3396 } 3397 atomic_add_int(&fdp->fd_softrefs, 1); 3398 spin_unlock(&p->p_spin); 3399 3400 /* 3401 * The fdp's own spinlock prevents the contents from being 3402 * modified. 3403 */ 3404 spin_lock_shared(&fdp->fd_spin); 3405 for (n = 0; n < fdp->fd_nfiles; ++n) { 3406 if ((fp = fdp->fd_files[n].fp) == NULL) 3407 continue; 3408 if (info->req->oldptr == NULL) { 3409 ++info->count; 3410 } else { 3411 uid = p->p_ucred ? p->p_ucred->cr_uid : -1; 3412 kcore_make_file(&kf, fp, p->p_pid, uid, n); 3413 spin_unlock_shared(&fdp->fd_spin); 3414 info->error = SYSCTL_OUT(info->req, &kf, sizeof(kf)); 3415 spin_lock_shared(&fdp->fd_spin); 3416 if (info->error) 3417 break; 3418 } 3419 } 3420 spin_unlock_shared(&fdp->fd_spin); 3421 atomic_subtract_int(&fdp->fd_softrefs, 1); 3422 if (info->error) 3423 return(-1); 3424 return(0); 3425 } 3426 3427 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD, 3428 0, 0, sysctl_kern_file, "S,file", "Entire file table"); 3429 3430 SYSCTL_INT(_kern, OID_AUTO, minfilesperproc, CTLFLAG_RW, 3431 &minfilesperproc, 0, "Minimum files allowed open per process"); 3432 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW, 3433 &maxfilesperproc, 0, "Maximum files allowed open per process"); 3434 SYSCTL_INT(_kern, OID_AUTO, maxfilesperuser, CTLFLAG_RW, 3435 &maxfilesperuser, 0, "Maximum files allowed open per user"); 3436 3437 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW, 3438 &maxfiles, 0, "Maximum number of files"); 3439 3440 SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW, 3441 &maxfilesrootres, 0, "Descriptors reserved for root use"); 3442 3443 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD, 3444 &nfiles, 0, "System-wide number of open files"); 3445 3446 static void 3447 fildesc_drvinit(void *unused) 3448 { 3449 int fd; 3450 3451 for (fd = 0; fd < NUMFDESC; fd++) { 3452 make_dev(&fildesc_ops, fd, 3453 UID_BIN, GID_BIN, 0666, "fd/%d", fd); 3454 } 3455 3456 make_dev(&fildesc_ops, 0, UID_ROOT, GID_WHEEL, 0666, "stdin"); 3457 make_dev(&fildesc_ops, 1, UID_ROOT, GID_WHEEL, 0666, "stdout"); 3458 make_dev(&fildesc_ops, 2, UID_ROOT, GID_WHEEL, 0666, "stderr"); 3459 } 3460 3461 struct fileops badfileops = { 3462 .fo_read = badfo_readwrite, 3463 .fo_write = badfo_readwrite, 3464 .fo_ioctl = badfo_ioctl, 3465 .fo_kqfilter = badfo_kqfilter, 3466 .fo_stat = badfo_stat, 3467 .fo_close = badfo_close, 3468 .fo_shutdown = badfo_shutdown, 3469 .fo_seek = badfo_seek 3470 }; 3471 3472 int 3473 badfo_readwrite( 3474 struct file *fp, 3475 struct uio *uio, 3476 struct ucred *cred, 3477 int flags 3478 ) { 3479 return (EBADF); 3480 } 3481 3482 int 3483 badfo_ioctl(struct file *fp, u_long com, caddr_t data, 3484 struct ucred *cred, struct sysmsg *msgv) 3485 { 3486 return (EBADF); 3487 } 3488 3489 /* 3490 * Must return an error to prevent registration, typically 3491 * due to a revoked descriptor (file_filtops assigned). 3492 */ 3493 int 3494 badfo_kqfilter(struct file *fp, struct knote *kn) 3495 { 3496 return (EOPNOTSUPP); 3497 } 3498 3499 int 3500 badfo_stat(struct file *fp, struct stat *sb, struct ucred *cred) 3501 { 3502 return (EBADF); 3503 } 3504 3505 int 3506 badfo_close(struct file *fp) 3507 { 3508 return (EBADF); 3509 } 3510 3511 int 3512 badfo_shutdown(struct file *fp, int how) 3513 { 3514 return (EBADF); 3515 } 3516 3517 int 3518 nofo_shutdown(struct file *fp, int how) 3519 { 3520 return (EOPNOTSUPP); 3521 } 3522 3523 int 3524 badfo_seek(struct file *fp, off_t offset, int whence, off_t *res) 3525 { 3526 return (ESPIPE); 3527 } 3528 3529 SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR, 3530 fildesc_drvinit,NULL); 3531 3532 static void 3533 filelist_heads_init(void *arg __unused) 3534 { 3535 int i; 3536 3537 for (i = 0; i < NFILELIST_HEADS; ++i) { 3538 struct filelist_head *head = &filelist_heads[i]; 3539 3540 spin_init(&head->spin, "filehead_spin"); 3541 LIST_INIT(&head->list); 3542 } 3543 } 3544 3545 SYSINIT(filelistheads, SI_BOOT1_LOCK, SI_ORDER_ANY, filelist_heads_init, NULL); 3546