1 /* $NetBSD: kern_descrip.c,v 1.255 2023/02/24 11:02:27 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 1982, 1986, 1989, 1991, 1993 34 * The Regents of the University of California. All rights reserved. 35 * (c) UNIX System Laboratories, Inc. 36 * All or some portions of this file are derived from material licensed 37 * to the University of California by American Telephone and Telegraph 38 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 39 * the permission of UNIX System Laboratories, Inc. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 3. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 * 65 * @(#)kern_descrip.c 8.8 (Berkeley) 2/14/95 66 */ 67 68 /* 69 * File descriptor management. 70 */ 71 72 #include <sys/cdefs.h> 73 __KERNEL_RCSID(0, "$NetBSD: kern_descrip.c,v 1.255 2023/02/24 11:02:27 riastradh Exp $"); 74 75 #include <sys/param.h> 76 #include <sys/systm.h> 77 #include <sys/filedesc.h> 78 #include <sys/kernel.h> 79 #include <sys/proc.h> 80 #include <sys/file.h> 81 #include <sys/socket.h> 82 #include <sys/socketvar.h> 83 #include <sys/stat.h> 84 #include <sys/ioctl.h> 85 #include <sys/fcntl.h> 86 #include <sys/pool.h> 87 #include <sys/unistd.h> 88 #include <sys/resourcevar.h> 89 #include <sys/conf.h> 90 #include <sys/event.h> 91 #include <sys/kauth.h> 92 #include <sys/atomic.h> 93 #include <sys/syscallargs.h> 94 #include <sys/cpu.h> 95 #include <sys/kmem.h> 96 #include <sys/vnode.h> 97 #include <sys/sysctl.h> 98 #include <sys/ktrace.h> 99 100 /* 101 * A list (head) of open files, counter, and lock protecting them. 102 */ 103 struct filelist filehead __cacheline_aligned; 104 static u_int nfiles __cacheline_aligned; 105 kmutex_t filelist_lock __cacheline_aligned; 106 107 static pool_cache_t filedesc_cache __read_mostly; 108 static pool_cache_t file_cache __read_mostly; 109 static pool_cache_t fdfile_cache __read_mostly; 110 111 static int file_ctor(void *, void *, int); 112 static void file_dtor(void *, void *); 113 static int fdfile_ctor(void *, void *, int); 114 static void fdfile_dtor(void *, void *); 115 static int filedesc_ctor(void *, void *, int); 116 static void filedesc_dtor(void *, void *); 117 static int filedescopen(dev_t, int, int, lwp_t *); 118 119 static int sysctl_kern_file(SYSCTLFN_PROTO); 120 static int sysctl_kern_file2(SYSCTLFN_PROTO); 121 static void fill_file(struct file *, const struct file *); 122 static void fill_file2(struct kinfo_file *, const file_t *, const fdfile_t *, 123 int, pid_t); 124 125 const struct cdevsw filedesc_cdevsw = { 126 .d_open = filedescopen, 127 .d_close = noclose, 128 .d_read = noread, 129 .d_write = nowrite, 130 .d_ioctl = noioctl, 131 .d_stop = nostop, 132 .d_tty = notty, 133 .d_poll = nopoll, 134 .d_mmap = nommap, 135 .d_kqfilter = nokqfilter, 136 .d_discard = nodiscard, 137 .d_flag = D_OTHER | D_MPSAFE 138 }; 139 140 /* For ease of reading. */ 141 __strong_alias(fd_putvnode,fd_putfile) 142 __strong_alias(fd_putsock,fd_putfile) 143 144 /* 145 * Initialize the descriptor system. 146 */ 147 void 148 fd_sys_init(void) 149 { 150 static struct sysctllog *clog; 151 152 mutex_init(&filelist_lock, MUTEX_DEFAULT, IPL_NONE); 153 154 LIST_INIT(&filehead); 155 156 file_cache = pool_cache_init(sizeof(file_t), coherency_unit, 0, 157 0, "file", NULL, IPL_NONE, file_ctor, file_dtor, NULL); 158 KASSERT(file_cache != NULL); 159 160 fdfile_cache = pool_cache_init(sizeof(fdfile_t), coherency_unit, 0, 161 PR_LARGECACHE, "fdfile", NULL, IPL_NONE, fdfile_ctor, fdfile_dtor, 162 NULL); 163 KASSERT(fdfile_cache != NULL); 164 165 filedesc_cache = pool_cache_init(sizeof(filedesc_t), coherency_unit, 166 0, 0, "filedesc", NULL, IPL_NONE, filedesc_ctor, filedesc_dtor, 167 NULL); 168 KASSERT(filedesc_cache != NULL); 169 170 sysctl_createv(&clog, 0, NULL, NULL, 171 CTLFLAG_PERMANENT, 172 CTLTYPE_STRUCT, "file", 173 SYSCTL_DESCR("System open file table"), 174 sysctl_kern_file, 0, NULL, 0, 175 CTL_KERN, KERN_FILE, CTL_EOL); 176 sysctl_createv(&clog, 0, NULL, NULL, 177 CTLFLAG_PERMANENT, 178 CTLTYPE_STRUCT, "file2", 179 SYSCTL_DESCR("System open file table"), 180 sysctl_kern_file2, 0, NULL, 0, 181 CTL_KERN, KERN_FILE2, CTL_EOL); 182 } 183 184 static bool 185 fd_isused(filedesc_t *fdp, unsigned fd) 186 { 187 u_int off = fd >> NDENTRYSHIFT; 188 189 KASSERT(fd < atomic_load_consume(&fdp->fd_dt)->dt_nfiles); 190 191 return (fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) != 0; 192 } 193 194 /* 195 * Verify that the bitmaps match the descriptor table. 196 */ 197 static inline void 198 fd_checkmaps(filedesc_t *fdp) 199 { 200 #ifdef DEBUG 201 fdtab_t *dt; 202 u_int fd; 203 204 KASSERT(fdp->fd_refcnt <= 1 || mutex_owned(&fdp->fd_lock)); 205 206 dt = fdp->fd_dt; 207 if (fdp->fd_refcnt == -1) { 208 /* 209 * fd_free tears down the table without maintaining its bitmap. 210 */ 211 return; 212 } 213 for (fd = 0; fd < dt->dt_nfiles; fd++) { 214 if (fd < NDFDFILE) { 215 KASSERT(dt->dt_ff[fd] == 216 (fdfile_t *)fdp->fd_dfdfile[fd]); 217 } 218 if (dt->dt_ff[fd] == NULL) { 219 KASSERT(!fd_isused(fdp, fd)); 220 } else if (dt->dt_ff[fd]->ff_file != NULL) { 221 KASSERT(fd_isused(fdp, fd)); 222 } 223 } 224 #endif 225 } 226 227 static int 228 fd_next_zero(filedesc_t *fdp, uint32_t *bitmap, int want, u_int bits) 229 { 230 int i, off, maxoff; 231 uint32_t sub; 232 233 KASSERT(mutex_owned(&fdp->fd_lock)); 234 235 fd_checkmaps(fdp); 236 237 if (want > bits) 238 return -1; 239 240 off = want >> NDENTRYSHIFT; 241 i = want & NDENTRYMASK; 242 if (i) { 243 sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i)); 244 if (sub != ~0) 245 goto found; 246 off++; 247 } 248 249 maxoff = NDLOSLOTS(bits); 250 while (off < maxoff) { 251 if ((sub = bitmap[off]) != ~0) 252 goto found; 253 off++; 254 } 255 256 return -1; 257 258 found: 259 return (off << NDENTRYSHIFT) + ffs(~sub) - 1; 260 } 261 262 static int 263 fd_last_set(filedesc_t *fd, int last) 264 { 265 int off, i; 266 fdfile_t **ff = fd->fd_dt->dt_ff; 267 uint32_t *bitmap = fd->fd_lomap; 268 269 KASSERT(mutex_owned(&fd->fd_lock)); 270 271 fd_checkmaps(fd); 272 273 off = (last - 1) >> NDENTRYSHIFT; 274 275 while (off >= 0 && !bitmap[off]) 276 off--; 277 278 if (off < 0) 279 return -1; 280 281 i = ((off + 1) << NDENTRYSHIFT) - 1; 282 if (i >= last) 283 i = last - 1; 284 285 /* XXX should use bitmap */ 286 while (i > 0 && (ff[i] == NULL || !ff[i]->ff_allocated)) 287 i--; 288 289 return i; 290 } 291 292 static inline void 293 fd_used(filedesc_t *fdp, unsigned fd) 294 { 295 u_int off = fd >> NDENTRYSHIFT; 296 fdfile_t *ff; 297 298 ff = fdp->fd_dt->dt_ff[fd]; 299 300 KASSERT(mutex_owned(&fdp->fd_lock)); 301 KASSERT((fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) == 0); 302 KASSERT(ff != NULL); 303 KASSERT(ff->ff_file == NULL); 304 KASSERT(!ff->ff_allocated); 305 306 ff->ff_allocated = true; 307 fdp->fd_lomap[off] |= 1U << (fd & NDENTRYMASK); 308 if (__predict_false(fdp->fd_lomap[off] == ~0)) { 309 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & 310 (1U << (off & NDENTRYMASK))) == 0); 311 fdp->fd_himap[off >> NDENTRYSHIFT] |= 1U << (off & NDENTRYMASK); 312 } 313 314 if ((int)fd > fdp->fd_lastfile) { 315 fdp->fd_lastfile = fd; 316 } 317 318 fd_checkmaps(fdp); 319 } 320 321 static inline void 322 fd_unused(filedesc_t *fdp, unsigned fd) 323 { 324 u_int off = fd >> NDENTRYSHIFT; 325 fdfile_t *ff; 326 327 ff = fdp->fd_dt->dt_ff[fd]; 328 329 KASSERT(mutex_owned(&fdp->fd_lock)); 330 KASSERT(ff != NULL); 331 KASSERT(ff->ff_file == NULL); 332 KASSERT(ff->ff_allocated); 333 334 if (fd < fdp->fd_freefile) { 335 fdp->fd_freefile = fd; 336 } 337 338 if (fdp->fd_lomap[off] == ~0) { 339 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & 340 (1U << (off & NDENTRYMASK))) != 0); 341 fdp->fd_himap[off >> NDENTRYSHIFT] &= 342 ~(1U << (off & NDENTRYMASK)); 343 } 344 KASSERT((fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) != 0); 345 fdp->fd_lomap[off] &= ~(1U << (fd & NDENTRYMASK)); 346 ff->ff_allocated = false; 347 348 KASSERT(fd <= fdp->fd_lastfile); 349 if (fd == fdp->fd_lastfile) { 350 fdp->fd_lastfile = fd_last_set(fdp, fd); 351 } 352 fd_checkmaps(fdp); 353 } 354 355 /* 356 * Look up the file structure corresponding to a file descriptor 357 * and return the file, holding a reference on the descriptor. 358 */ 359 file_t * 360 fd_getfile(unsigned fd) 361 { 362 filedesc_t *fdp; 363 fdfile_t *ff; 364 file_t *fp; 365 fdtab_t *dt; 366 367 /* 368 * Look up the fdfile structure representing this descriptor. 369 * We are doing this unlocked. See fd_tryexpand(). 370 */ 371 fdp = curlwp->l_fd; 372 dt = atomic_load_consume(&fdp->fd_dt); 373 if (__predict_false(fd >= dt->dt_nfiles)) { 374 return NULL; 375 } 376 ff = dt->dt_ff[fd]; 377 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 378 if (__predict_false(ff == NULL)) { 379 return NULL; 380 } 381 382 /* Now get a reference to the descriptor. */ 383 if (fdp->fd_refcnt == 1) { 384 /* 385 * Single threaded: don't need to worry about concurrent 386 * access (other than earlier calls to kqueue, which may 387 * hold a reference to the descriptor). 388 */ 389 ff->ff_refcnt++; 390 } else { 391 /* 392 * Multi threaded: issue a memory barrier to ensure that we 393 * acquire the file pointer _after_ adding a reference. If 394 * no memory barrier, we could fetch a stale pointer. 395 * 396 * In particular, we must coordinate the following four 397 * memory operations: 398 * 399 * A. fd_close store ff->ff_file = NULL 400 * B. fd_close refcnt = atomic_dec_uint_nv(&ff->ff_refcnt) 401 * C. fd_getfile atomic_inc_uint(&ff->ff_refcnt) 402 * D. fd_getfile load fp = ff->ff_file 403 * 404 * If the order is D;A;B;C: 405 * 406 * 1. D: fp = ff->ff_file 407 * 2. A: ff->ff_file = NULL 408 * 3. B: refcnt = atomic_dec_uint_nv(&ff->ff_refcnt) 409 * 4. C: atomic_inc_uint(&ff->ff_refcnt) 410 * 411 * then fd_close determines that there are no more 412 * references and decides to free fp immediately, at 413 * the same that fd_getfile ends up with an fp that's 414 * about to be freed. *boom* 415 * 416 * By making B a release operation in fd_close, and by 417 * making C an acquire operation in fd_getfile, since 418 * they are atomic operations on the same object, which 419 * has a total modification order, we guarantee either: 420 * 421 * - B happens before C. Then since A is 422 * sequenced before B in fd_close, and C is 423 * sequenced before D in fd_getfile, we 424 * guarantee A happens before D, so fd_getfile 425 * reads a null fp and safely fails. 426 * 427 * - C happens before B. Then fd_getfile may read 428 * null or nonnull, but either way, fd_close 429 * will safely wait for references to drain. 430 */ 431 atomic_inc_uint(&ff->ff_refcnt); 432 membar_acquire(); 433 } 434 435 /* 436 * If the file is not open or is being closed then put the 437 * reference back. 438 */ 439 fp = atomic_load_consume(&ff->ff_file); 440 if (__predict_true(fp != NULL)) { 441 return fp; 442 } 443 fd_putfile(fd); 444 return NULL; 445 } 446 447 /* 448 * Release a reference to a file descriptor acquired with fd_getfile(). 449 */ 450 void 451 fd_putfile(unsigned fd) 452 { 453 filedesc_t *fdp; 454 fdfile_t *ff; 455 u_int u, v; 456 457 fdp = curlwp->l_fd; 458 KASSERT(fd < atomic_load_consume(&fdp->fd_dt)->dt_nfiles); 459 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd]; 460 461 KASSERT(ff != NULL); 462 KASSERT((ff->ff_refcnt & FR_MASK) > 0); 463 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 464 465 if (fdp->fd_refcnt == 1) { 466 /* 467 * Single threaded: don't need to worry about concurrent 468 * access (other than earlier calls to kqueue, which may 469 * hold a reference to the descriptor). 470 */ 471 if (__predict_false((ff->ff_refcnt & FR_CLOSING) != 0)) { 472 fd_close(fd); 473 return; 474 } 475 ff->ff_refcnt--; 476 return; 477 } 478 479 /* 480 * Ensure that any use of the file is complete and globally 481 * visible before dropping the final reference. If no membar, 482 * the current CPU could still access memory associated with 483 * the file after it has been freed or recycled by another 484 * CPU. 485 */ 486 membar_release(); 487 488 /* 489 * Be optimistic and start out with the assumption that no other 490 * threads are trying to close the descriptor. If the CAS fails, 491 * we lost a race and/or it's being closed. 492 */ 493 for (u = ff->ff_refcnt & FR_MASK;; u = v) { 494 v = atomic_cas_uint(&ff->ff_refcnt, u, u - 1); 495 if (__predict_true(u == v)) { 496 return; 497 } 498 if (__predict_false((v & FR_CLOSING) != 0)) { 499 break; 500 } 501 } 502 503 /* Another thread is waiting to close the file: join it. */ 504 (void)fd_close(fd); 505 } 506 507 /* 508 * Convenience wrapper around fd_getfile() that returns reference 509 * to a vnode. 510 */ 511 int 512 fd_getvnode(unsigned fd, file_t **fpp) 513 { 514 vnode_t *vp; 515 file_t *fp; 516 517 fp = fd_getfile(fd); 518 if (__predict_false(fp == NULL)) { 519 return EBADF; 520 } 521 if (__predict_false(fp->f_type != DTYPE_VNODE)) { 522 fd_putfile(fd); 523 return EINVAL; 524 } 525 vp = fp->f_vnode; 526 if (__predict_false(vp->v_type == VBAD)) { 527 /* XXX Is this case really necessary? */ 528 fd_putfile(fd); 529 return EBADF; 530 } 531 *fpp = fp; 532 return 0; 533 } 534 535 /* 536 * Convenience wrapper around fd_getfile() that returns reference 537 * to a socket. 538 */ 539 int 540 fd_getsock1(unsigned fd, struct socket **sop, file_t **fp) 541 { 542 *fp = fd_getfile(fd); 543 if (__predict_false(*fp == NULL)) { 544 return EBADF; 545 } 546 if (__predict_false((*fp)->f_type != DTYPE_SOCKET)) { 547 fd_putfile(fd); 548 return ENOTSOCK; 549 } 550 *sop = (*fp)->f_socket; 551 return 0; 552 } 553 554 int 555 fd_getsock(unsigned fd, struct socket **sop) 556 { 557 file_t *fp; 558 return fd_getsock1(fd, sop, &fp); 559 } 560 561 /* 562 * Look up the file structure corresponding to a file descriptor 563 * and return it with a reference held on the file, not the 564 * descriptor. 565 * 566 * This is heavyweight and only used when accessing descriptors 567 * from a foreign process. The caller must ensure that `p' does 568 * not exit or fork across this call. 569 * 570 * To release the file (not descriptor) reference, use closef(). 571 */ 572 file_t * 573 fd_getfile2(proc_t *p, unsigned fd) 574 { 575 filedesc_t *fdp; 576 fdfile_t *ff; 577 file_t *fp; 578 fdtab_t *dt; 579 580 fdp = p->p_fd; 581 mutex_enter(&fdp->fd_lock); 582 dt = fdp->fd_dt; 583 if (fd >= dt->dt_nfiles) { 584 mutex_exit(&fdp->fd_lock); 585 return NULL; 586 } 587 if ((ff = dt->dt_ff[fd]) == NULL) { 588 mutex_exit(&fdp->fd_lock); 589 return NULL; 590 } 591 if ((fp = atomic_load_consume(&ff->ff_file)) == NULL) { 592 mutex_exit(&fdp->fd_lock); 593 return NULL; 594 } 595 mutex_enter(&fp->f_lock); 596 fp->f_count++; 597 mutex_exit(&fp->f_lock); 598 mutex_exit(&fdp->fd_lock); 599 600 return fp; 601 } 602 603 /* 604 * Internal form of close. Must be called with a reference to the 605 * descriptor, and will drop the reference. When all descriptor 606 * references are dropped, releases the descriptor slot and a single 607 * reference to the file structure. 608 */ 609 int 610 fd_close(unsigned fd) 611 { 612 struct flock lf; 613 filedesc_t *fdp; 614 fdfile_t *ff; 615 file_t *fp; 616 proc_t *p; 617 lwp_t *l; 618 u_int refcnt; 619 620 l = curlwp; 621 p = l->l_proc; 622 fdp = l->l_fd; 623 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd]; 624 625 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 626 627 mutex_enter(&fdp->fd_lock); 628 KASSERT((ff->ff_refcnt & FR_MASK) > 0); 629 fp = atomic_load_consume(&ff->ff_file); 630 if (__predict_false(fp == NULL)) { 631 /* 632 * Another user of the file is already closing, and is 633 * waiting for other users of the file to drain. Release 634 * our reference, and wake up the closer. 635 */ 636 membar_release(); 637 atomic_dec_uint(&ff->ff_refcnt); 638 cv_broadcast(&ff->ff_closing); 639 mutex_exit(&fdp->fd_lock); 640 641 /* 642 * An application error, so pretend that the descriptor 643 * was already closed. We can't safely wait for it to 644 * be closed without potentially deadlocking. 645 */ 646 return (EBADF); 647 } 648 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); 649 650 /* 651 * There may be multiple users of this file within the process. 652 * Notify existing and new users that the file is closing. This 653 * will prevent them from adding additional uses to this file 654 * while we are closing it. 655 */ 656 atomic_store_relaxed(&ff->ff_file, NULL); 657 ff->ff_exclose = false; 658 659 /* 660 * We expect the caller to hold a descriptor reference - drop it. 661 * The reference count may increase beyond zero at this point due 662 * to an erroneous descriptor reference by an application, but 663 * fd_getfile() will notice that the file is being closed and drop 664 * the reference again. 665 */ 666 if (fdp->fd_refcnt == 1) { 667 /* Single threaded. */ 668 refcnt = --(ff->ff_refcnt); 669 } else { 670 /* Multi threaded. */ 671 membar_release(); 672 refcnt = atomic_dec_uint_nv(&ff->ff_refcnt); 673 membar_acquire(); 674 } 675 if (__predict_false(refcnt != 0)) { 676 /* 677 * Wait for other references to drain. This is typically 678 * an application error - the descriptor is being closed 679 * while still in use. 680 * (Or just a threaded application trying to unblock its 681 * thread that sleeps in (say) accept()). 682 */ 683 atomic_or_uint(&ff->ff_refcnt, FR_CLOSING); 684 685 /* 686 * Remove any knotes attached to the file. A knote 687 * attached to the descriptor can hold references on it. 688 */ 689 mutex_exit(&fdp->fd_lock); 690 if (!SLIST_EMPTY(&ff->ff_knlist)) { 691 knote_fdclose(fd); 692 } 693 694 /* 695 * Since the file system code doesn't know which fd 696 * each request came from (think dup()), we have to 697 * ask it to return ERESTART for any long-term blocks. 698 * The re-entry through read/write/etc will detect the 699 * closed fd and return EBAFD. 700 * Blocked partial writes may return a short length. 701 */ 702 (*fp->f_ops->fo_restart)(fp); 703 mutex_enter(&fdp->fd_lock); 704 705 /* 706 * We need to see the count drop to zero at least once, 707 * in order to ensure that all pre-existing references 708 * have been drained. New references past this point are 709 * of no interest. 710 * XXX (dsl) this may need to call fo_restart() after a 711 * timeout to guarantee that all the system calls exit. 712 */ 713 while ((ff->ff_refcnt & FR_MASK) != 0) { 714 cv_wait(&ff->ff_closing, &fdp->fd_lock); 715 } 716 atomic_and_uint(&ff->ff_refcnt, ~FR_CLOSING); 717 } else { 718 /* If no references, there must be no knotes. */ 719 KASSERT(SLIST_EMPTY(&ff->ff_knlist)); 720 } 721 722 /* 723 * POSIX record locking dictates that any close releases ALL 724 * locks owned by this process. This is handled by setting 725 * a flag in the unlock to free ONLY locks obeying POSIX 726 * semantics, and not to free BSD-style file locks. 727 * If the descriptor was in a message, POSIX-style locks 728 * aren't passed with the descriptor. 729 */ 730 if (__predict_false((p->p_flag & PK_ADVLOCK) != 0 && 731 fp->f_type == DTYPE_VNODE)) { 732 lf.l_whence = SEEK_SET; 733 lf.l_start = 0; 734 lf.l_len = 0; 735 lf.l_type = F_UNLCK; 736 mutex_exit(&fdp->fd_lock); 737 (void)VOP_ADVLOCK(fp->f_vnode, p, F_UNLCK, &lf, F_POSIX); 738 mutex_enter(&fdp->fd_lock); 739 } 740 741 /* Free descriptor slot. */ 742 fd_unused(fdp, fd); 743 mutex_exit(&fdp->fd_lock); 744 745 /* Now drop reference to the file itself. */ 746 return closef(fp); 747 } 748 749 /* 750 * Duplicate a file descriptor. 751 */ 752 int 753 fd_dup(file_t *fp, int minfd, int *newp, bool exclose) 754 { 755 proc_t *p = curproc; 756 fdtab_t *dt; 757 int error; 758 759 while ((error = fd_alloc(p, minfd, newp)) != 0) { 760 if (error != ENOSPC) { 761 return error; 762 } 763 fd_tryexpand(p); 764 } 765 766 dt = atomic_load_consume(&curlwp->l_fd->fd_dt); 767 dt->dt_ff[*newp]->ff_exclose = exclose; 768 fd_affix(p, fp, *newp); 769 return 0; 770 } 771 772 /* 773 * dup2 operation. 774 */ 775 int 776 fd_dup2(file_t *fp, unsigned newfd, int flags) 777 { 778 filedesc_t *fdp = curlwp->l_fd; 779 fdfile_t *ff; 780 fdtab_t *dt; 781 782 if (flags & ~(O_CLOEXEC|O_NONBLOCK|O_NOSIGPIPE)) 783 return EINVAL; 784 /* 785 * Ensure there are enough slots in the descriptor table, 786 * and allocate an fdfile_t up front in case we need it. 787 */ 788 while (newfd >= atomic_load_consume(&fdp->fd_dt)->dt_nfiles) { 789 fd_tryexpand(curproc); 790 } 791 ff = pool_cache_get(fdfile_cache, PR_WAITOK); 792 793 /* 794 * If there is already a file open, close it. If the file is 795 * half open, wait for it to be constructed before closing it. 796 * XXX Potential for deadlock here? 797 */ 798 mutex_enter(&fdp->fd_lock); 799 while (fd_isused(fdp, newfd)) { 800 mutex_exit(&fdp->fd_lock); 801 if (fd_getfile(newfd) != NULL) { 802 (void)fd_close(newfd); 803 } else { 804 /* 805 * Crummy, but unlikely to happen. 806 * Can occur if we interrupt another 807 * thread while it is opening a file. 808 */ 809 kpause("dup2", false, 1, NULL); 810 } 811 mutex_enter(&fdp->fd_lock); 812 } 813 dt = fdp->fd_dt; 814 if (dt->dt_ff[newfd] == NULL) { 815 KASSERT(newfd >= NDFDFILE); 816 dt->dt_ff[newfd] = ff; 817 ff = NULL; 818 } 819 fd_used(fdp, newfd); 820 mutex_exit(&fdp->fd_lock); 821 822 dt->dt_ff[newfd]->ff_exclose = (flags & O_CLOEXEC) != 0; 823 fp->f_flag |= flags & (FNONBLOCK|FNOSIGPIPE); 824 /* Slot is now allocated. Insert copy of the file. */ 825 fd_affix(curproc, fp, newfd); 826 if (ff != NULL) { 827 pool_cache_put(fdfile_cache, ff); 828 } 829 return 0; 830 } 831 832 /* 833 * Drop reference to a file structure. 834 */ 835 int 836 closef(file_t *fp) 837 { 838 struct flock lf; 839 int error; 840 841 /* 842 * Drop reference. If referenced elsewhere it's still open 843 * and we have nothing more to do. 844 */ 845 mutex_enter(&fp->f_lock); 846 KASSERT(fp->f_count > 0); 847 if (--fp->f_count > 0) { 848 mutex_exit(&fp->f_lock); 849 return 0; 850 } 851 KASSERT(fp->f_count == 0); 852 mutex_exit(&fp->f_lock); 853 854 /* We held the last reference - release locks, close and free. */ 855 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) { 856 lf.l_whence = SEEK_SET; 857 lf.l_start = 0; 858 lf.l_len = 0; 859 lf.l_type = F_UNLCK; 860 (void)VOP_ADVLOCK(fp->f_vnode, fp, F_UNLCK, &lf, F_FLOCK); 861 } 862 if (fp->f_ops != NULL) { 863 error = (*fp->f_ops->fo_close)(fp); 864 } else { 865 error = 0; 866 } 867 KASSERT(fp->f_count == 0); 868 KASSERT(fp->f_cred != NULL); 869 pool_cache_put(file_cache, fp); 870 871 return error; 872 } 873 874 /* 875 * Allocate a file descriptor for the process. 876 */ 877 int 878 fd_alloc(proc_t *p, int want, int *result) 879 { 880 filedesc_t *fdp = p->p_fd; 881 int i, lim, last, error, hi; 882 u_int off; 883 fdtab_t *dt; 884 885 KASSERT(p == curproc || p == &proc0); 886 887 /* 888 * Search for a free descriptor starting at the higher 889 * of want or fd_freefile. 890 */ 891 mutex_enter(&fdp->fd_lock); 892 fd_checkmaps(fdp); 893 dt = fdp->fd_dt; 894 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 895 lim = uimin((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles); 896 last = uimin(dt->dt_nfiles, lim); 897 for (;;) { 898 if ((i = want) < fdp->fd_freefile) 899 i = fdp->fd_freefile; 900 off = i >> NDENTRYSHIFT; 901 hi = fd_next_zero(fdp, fdp->fd_himap, off, 902 (last + NDENTRIES - 1) >> NDENTRYSHIFT); 903 if (hi == -1) 904 break; 905 i = fd_next_zero(fdp, &fdp->fd_lomap[hi], 906 hi > off ? 0 : i & NDENTRYMASK, NDENTRIES); 907 if (i == -1) { 908 /* 909 * Free file descriptor in this block was 910 * below want, try again with higher want. 911 */ 912 want = (hi + 1) << NDENTRYSHIFT; 913 continue; 914 } 915 i += (hi << NDENTRYSHIFT); 916 if (i >= last) { 917 break; 918 } 919 if (dt->dt_ff[i] == NULL) { 920 KASSERT(i >= NDFDFILE); 921 dt->dt_ff[i] = pool_cache_get(fdfile_cache, PR_WAITOK); 922 } 923 KASSERT(dt->dt_ff[i]->ff_file == NULL); 924 fd_used(fdp, i); 925 if (want <= fdp->fd_freefile) { 926 fdp->fd_freefile = i; 927 } 928 *result = i; 929 KASSERT(i >= NDFDFILE || 930 dt->dt_ff[i] == (fdfile_t *)fdp->fd_dfdfile[i]); 931 fd_checkmaps(fdp); 932 mutex_exit(&fdp->fd_lock); 933 return 0; 934 } 935 936 /* No space in current array. Let the caller expand and retry. */ 937 error = (dt->dt_nfiles >= lim) ? EMFILE : ENOSPC; 938 mutex_exit(&fdp->fd_lock); 939 return error; 940 } 941 942 /* 943 * Allocate memory for a descriptor table. 944 */ 945 static fdtab_t * 946 fd_dtab_alloc(int n) 947 { 948 fdtab_t *dt; 949 size_t sz; 950 951 KASSERT(n > NDFILE); 952 953 sz = sizeof(*dt) + (n - NDFILE) * sizeof(dt->dt_ff[0]); 954 dt = kmem_alloc(sz, KM_SLEEP); 955 #ifdef DIAGNOSTIC 956 memset(dt, 0xff, sz); 957 #endif 958 dt->dt_nfiles = n; 959 dt->dt_link = NULL; 960 return dt; 961 } 962 963 /* 964 * Free a descriptor table, and all tables linked for deferred free. 965 */ 966 static void 967 fd_dtab_free(fdtab_t *dt) 968 { 969 fdtab_t *next; 970 size_t sz; 971 972 do { 973 next = dt->dt_link; 974 KASSERT(dt->dt_nfiles > NDFILE); 975 sz = sizeof(*dt) + 976 (dt->dt_nfiles - NDFILE) * sizeof(dt->dt_ff[0]); 977 #ifdef DIAGNOSTIC 978 memset(dt, 0xff, sz); 979 #endif 980 kmem_free(dt, sz); 981 dt = next; 982 } while (dt != NULL); 983 } 984 985 /* 986 * Allocate descriptor bitmap. 987 */ 988 static void 989 fd_map_alloc(int n, uint32_t **lo, uint32_t **hi) 990 { 991 uint8_t *ptr; 992 size_t szlo, szhi; 993 994 KASSERT(n > NDENTRIES); 995 996 szlo = NDLOSLOTS(n) * sizeof(uint32_t); 997 szhi = NDHISLOTS(n) * sizeof(uint32_t); 998 ptr = kmem_alloc(szlo + szhi, KM_SLEEP); 999 *lo = (uint32_t *)ptr; 1000 *hi = (uint32_t *)(ptr + szlo); 1001 } 1002 1003 /* 1004 * Free descriptor bitmap. 1005 */ 1006 static void 1007 fd_map_free(int n, uint32_t *lo, uint32_t *hi) 1008 { 1009 size_t szlo, szhi; 1010 1011 KASSERT(n > NDENTRIES); 1012 1013 szlo = NDLOSLOTS(n) * sizeof(uint32_t); 1014 szhi = NDHISLOTS(n) * sizeof(uint32_t); 1015 KASSERT(hi == (uint32_t *)((uint8_t *)lo + szlo)); 1016 kmem_free(lo, szlo + szhi); 1017 } 1018 1019 /* 1020 * Expand a process' descriptor table. 1021 */ 1022 void 1023 fd_tryexpand(proc_t *p) 1024 { 1025 filedesc_t *fdp; 1026 int i, numfiles, oldnfiles; 1027 fdtab_t *newdt, *dt; 1028 uint32_t *newhimap, *newlomap; 1029 1030 KASSERT(p == curproc || p == &proc0); 1031 1032 fdp = p->p_fd; 1033 newhimap = NULL; 1034 newlomap = NULL; 1035 oldnfiles = atomic_load_consume(&fdp->fd_dt)->dt_nfiles; 1036 1037 if (oldnfiles < NDEXTENT) 1038 numfiles = NDEXTENT; 1039 else 1040 numfiles = 2 * oldnfiles; 1041 1042 newdt = fd_dtab_alloc(numfiles); 1043 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1044 fd_map_alloc(numfiles, &newlomap, &newhimap); 1045 } 1046 1047 mutex_enter(&fdp->fd_lock); 1048 dt = fdp->fd_dt; 1049 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1050 if (dt->dt_nfiles != oldnfiles) { 1051 /* fdp changed; caller must retry */ 1052 mutex_exit(&fdp->fd_lock); 1053 fd_dtab_free(newdt); 1054 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1055 fd_map_free(numfiles, newlomap, newhimap); 1056 } 1057 return; 1058 } 1059 1060 /* Copy the existing descriptor table and zero the new portion. */ 1061 i = sizeof(fdfile_t *) * oldnfiles; 1062 memcpy(newdt->dt_ff, dt->dt_ff, i); 1063 memset((uint8_t *)newdt->dt_ff + i, 0, 1064 numfiles * sizeof(fdfile_t *) - i); 1065 1066 /* 1067 * Link old descriptor array into list to be discarded. We defer 1068 * freeing until the last reference to the descriptor table goes 1069 * away (usually process exit). This allows us to do lockless 1070 * lookups in fd_getfile(). 1071 */ 1072 if (oldnfiles > NDFILE) { 1073 if (fdp->fd_refcnt > 1) { 1074 newdt->dt_link = dt; 1075 } else { 1076 fd_dtab_free(dt); 1077 } 1078 } 1079 1080 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1081 i = NDHISLOTS(oldnfiles) * sizeof(uint32_t); 1082 memcpy(newhimap, fdp->fd_himap, i); 1083 memset((uint8_t *)newhimap + i, 0, 1084 NDHISLOTS(numfiles) * sizeof(uint32_t) - i); 1085 1086 i = NDLOSLOTS(oldnfiles) * sizeof(uint32_t); 1087 memcpy(newlomap, fdp->fd_lomap, i); 1088 memset((uint8_t *)newlomap + i, 0, 1089 NDLOSLOTS(numfiles) * sizeof(uint32_t) - i); 1090 1091 if (NDHISLOTS(oldnfiles) > NDHISLOTS(NDFILE)) { 1092 fd_map_free(oldnfiles, fdp->fd_lomap, fdp->fd_himap); 1093 } 1094 fdp->fd_himap = newhimap; 1095 fdp->fd_lomap = newlomap; 1096 } 1097 1098 /* 1099 * All other modifications must become globally visible before 1100 * the change to fd_dt. See fd_getfile(). 1101 */ 1102 atomic_store_release(&fdp->fd_dt, newdt); 1103 KASSERT(newdt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1104 fd_checkmaps(fdp); 1105 mutex_exit(&fdp->fd_lock); 1106 } 1107 1108 /* 1109 * Create a new open file structure and allocate a file descriptor 1110 * for the current process. 1111 */ 1112 int 1113 fd_allocfile(file_t **resultfp, int *resultfd) 1114 { 1115 proc_t *p = curproc; 1116 kauth_cred_t cred; 1117 file_t *fp; 1118 int error; 1119 1120 while ((error = fd_alloc(p, 0, resultfd)) != 0) { 1121 if (error != ENOSPC) { 1122 return error; 1123 } 1124 fd_tryexpand(p); 1125 } 1126 1127 fp = pool_cache_get(file_cache, PR_WAITOK); 1128 if (fp == NULL) { 1129 fd_abort(p, NULL, *resultfd); 1130 return ENFILE; 1131 } 1132 KASSERT(fp->f_count == 0); 1133 KASSERT(fp->f_msgcount == 0); 1134 KASSERT(fp->f_unpcount == 0); 1135 1136 /* Replace cached credentials if not what we need. */ 1137 cred = curlwp->l_cred; 1138 if (__predict_false(cred != fp->f_cred)) { 1139 kauth_cred_free(fp->f_cred); 1140 kauth_cred_hold(cred); 1141 fp->f_cred = cred; 1142 } 1143 1144 /* 1145 * Don't allow recycled files to be scanned. 1146 * See uipc_usrreq.c. 1147 */ 1148 if (__predict_false((fp->f_flag & FSCAN) != 0)) { 1149 mutex_enter(&fp->f_lock); 1150 atomic_and_uint(&fp->f_flag, ~FSCAN); 1151 mutex_exit(&fp->f_lock); 1152 } 1153 1154 fp->f_advice = 0; 1155 fp->f_offset = 0; 1156 *resultfp = fp; 1157 1158 return 0; 1159 } 1160 1161 /* 1162 * Successful creation of a new descriptor: make visible to the process. 1163 */ 1164 void 1165 fd_affix(proc_t *p, file_t *fp, unsigned fd) 1166 { 1167 fdfile_t *ff; 1168 filedesc_t *fdp; 1169 fdtab_t *dt; 1170 1171 KASSERT(p == curproc || p == &proc0); 1172 1173 /* Add a reference to the file structure. */ 1174 mutex_enter(&fp->f_lock); 1175 fp->f_count++; 1176 mutex_exit(&fp->f_lock); 1177 1178 /* 1179 * Insert the new file into the descriptor slot. 1180 */ 1181 fdp = p->p_fd; 1182 dt = atomic_load_consume(&fdp->fd_dt); 1183 ff = dt->dt_ff[fd]; 1184 1185 KASSERT(ff != NULL); 1186 KASSERT(ff->ff_file == NULL); 1187 KASSERT(ff->ff_allocated); 1188 KASSERT(fd_isused(fdp, fd)); 1189 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1190 1191 /* No need to lock in order to make file initially visible. */ 1192 atomic_store_release(&ff->ff_file, fp); 1193 } 1194 1195 /* 1196 * Abort creation of a new descriptor: free descriptor slot and file. 1197 */ 1198 void 1199 fd_abort(proc_t *p, file_t *fp, unsigned fd) 1200 { 1201 filedesc_t *fdp; 1202 fdfile_t *ff; 1203 1204 KASSERT(p == curproc || p == &proc0); 1205 1206 fdp = p->p_fd; 1207 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd]; 1208 ff->ff_exclose = false; 1209 1210 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1211 1212 mutex_enter(&fdp->fd_lock); 1213 KASSERT(fd_isused(fdp, fd)); 1214 fd_unused(fdp, fd); 1215 mutex_exit(&fdp->fd_lock); 1216 1217 if (fp != NULL) { 1218 KASSERT(fp->f_count == 0); 1219 KASSERT(fp->f_cred != NULL); 1220 pool_cache_put(file_cache, fp); 1221 } 1222 } 1223 1224 static int 1225 file_ctor(void *arg, void *obj, int flags) 1226 { 1227 file_t *fp = obj; 1228 1229 memset(fp, 0, sizeof(*fp)); 1230 1231 mutex_enter(&filelist_lock); 1232 if (__predict_false(nfiles >= maxfiles)) { 1233 mutex_exit(&filelist_lock); 1234 tablefull("file", "increase kern.maxfiles or MAXFILES"); 1235 return ENFILE; 1236 } 1237 nfiles++; 1238 LIST_INSERT_HEAD(&filehead, fp, f_list); 1239 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); 1240 fp->f_cred = curlwp->l_cred; 1241 kauth_cred_hold(fp->f_cred); 1242 mutex_exit(&filelist_lock); 1243 1244 return 0; 1245 } 1246 1247 static void 1248 file_dtor(void *arg, void *obj) 1249 { 1250 file_t *fp = obj; 1251 1252 mutex_enter(&filelist_lock); 1253 nfiles--; 1254 LIST_REMOVE(fp, f_list); 1255 mutex_exit(&filelist_lock); 1256 1257 KASSERT(fp->f_count == 0); 1258 kauth_cred_free(fp->f_cred); 1259 mutex_destroy(&fp->f_lock); 1260 } 1261 1262 static int 1263 fdfile_ctor(void *arg, void *obj, int flags) 1264 { 1265 fdfile_t *ff = obj; 1266 1267 memset(ff, 0, sizeof(*ff)); 1268 cv_init(&ff->ff_closing, "fdclose"); 1269 1270 return 0; 1271 } 1272 1273 static void 1274 fdfile_dtor(void *arg, void *obj) 1275 { 1276 fdfile_t *ff = obj; 1277 1278 cv_destroy(&ff->ff_closing); 1279 } 1280 1281 file_t * 1282 fgetdummy(void) 1283 { 1284 file_t *fp; 1285 1286 fp = kmem_zalloc(sizeof(*fp), KM_SLEEP); 1287 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); 1288 return fp; 1289 } 1290 1291 void 1292 fputdummy(file_t *fp) 1293 { 1294 1295 mutex_destroy(&fp->f_lock); 1296 kmem_free(fp, sizeof(*fp)); 1297 } 1298 1299 /* 1300 * Create an initial filedesc structure. 1301 */ 1302 filedesc_t * 1303 fd_init(filedesc_t *fdp) 1304 { 1305 #ifdef DIAGNOSTIC 1306 unsigned fd; 1307 #endif 1308 1309 if (__predict_true(fdp == NULL)) { 1310 fdp = pool_cache_get(filedesc_cache, PR_WAITOK); 1311 } else { 1312 KASSERT(fdp == &filedesc0); 1313 filedesc_ctor(NULL, fdp, PR_WAITOK); 1314 } 1315 1316 #ifdef DIAGNOSTIC 1317 KASSERT(fdp->fd_lastfile == -1); 1318 KASSERT(fdp->fd_lastkqfile == -1); 1319 KASSERT(fdp->fd_knhash == NULL); 1320 KASSERT(fdp->fd_freefile == 0); 1321 KASSERT(fdp->fd_exclose == false); 1322 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin); 1323 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1324 for (fd = 0; fd < NDFDFILE; fd++) { 1325 KASSERT(fdp->fd_dtbuiltin.dt_ff[fd] == 1326 (fdfile_t *)fdp->fd_dfdfile[fd]); 1327 } 1328 for (fd = NDFDFILE; fd < NDFILE; fd++) { 1329 KASSERT(fdp->fd_dtbuiltin.dt_ff[fd] == NULL); 1330 } 1331 KASSERT(fdp->fd_himap == fdp->fd_dhimap); 1332 KASSERT(fdp->fd_lomap == fdp->fd_dlomap); 1333 #endif /* DIAGNOSTIC */ 1334 1335 fdp->fd_refcnt = 1; 1336 fd_checkmaps(fdp); 1337 1338 return fdp; 1339 } 1340 1341 /* 1342 * Initialize a file descriptor table. 1343 */ 1344 static int 1345 filedesc_ctor(void *arg, void *obj, int flag) 1346 { 1347 filedesc_t *fdp = obj; 1348 fdfile_t **ffp; 1349 int i; 1350 1351 memset(fdp, 0, sizeof(*fdp)); 1352 mutex_init(&fdp->fd_lock, MUTEX_DEFAULT, IPL_NONE); 1353 fdp->fd_lastfile = -1; 1354 fdp->fd_lastkqfile = -1; 1355 fdp->fd_dt = &fdp->fd_dtbuiltin; 1356 fdp->fd_dtbuiltin.dt_nfiles = NDFILE; 1357 fdp->fd_himap = fdp->fd_dhimap; 1358 fdp->fd_lomap = fdp->fd_dlomap; 1359 1360 CTASSERT(sizeof(fdp->fd_dfdfile[0]) >= sizeof(fdfile_t)); 1361 for (i = 0, ffp = fdp->fd_dt->dt_ff; i < NDFDFILE; i++, ffp++) { 1362 *ffp = (fdfile_t *)fdp->fd_dfdfile[i]; 1363 (void)fdfile_ctor(NULL, fdp->fd_dfdfile[i], PR_WAITOK); 1364 } 1365 1366 return 0; 1367 } 1368 1369 static void 1370 filedesc_dtor(void *arg, void *obj) 1371 { 1372 filedesc_t *fdp = obj; 1373 int i; 1374 1375 for (i = 0; i < NDFDFILE; i++) { 1376 fdfile_dtor(NULL, fdp->fd_dfdfile[i]); 1377 } 1378 1379 mutex_destroy(&fdp->fd_lock); 1380 } 1381 1382 /* 1383 * Make p share curproc's filedesc structure. 1384 */ 1385 void 1386 fd_share(struct proc *p) 1387 { 1388 filedesc_t *fdp; 1389 1390 fdp = curlwp->l_fd; 1391 p->p_fd = fdp; 1392 atomic_inc_uint(&fdp->fd_refcnt); 1393 } 1394 1395 /* 1396 * Acquire a hold on a filedesc structure. 1397 */ 1398 void 1399 fd_hold(lwp_t *l) 1400 { 1401 filedesc_t *fdp = l->l_fd; 1402 1403 atomic_inc_uint(&fdp->fd_refcnt); 1404 } 1405 1406 /* 1407 * Copy a filedesc structure. 1408 */ 1409 filedesc_t * 1410 fd_copy(void) 1411 { 1412 filedesc_t *newfdp, *fdp; 1413 fdfile_t *ff, **ffp, **nffp, *ff2; 1414 int i, j, numfiles, lastfile, newlast; 1415 file_t *fp; 1416 fdtab_t *newdt; 1417 1418 fdp = curproc->p_fd; 1419 newfdp = pool_cache_get(filedesc_cache, PR_WAITOK); 1420 newfdp->fd_refcnt = 1; 1421 1422 #ifdef DIAGNOSTIC 1423 KASSERT(newfdp->fd_lastfile == -1); 1424 KASSERT(newfdp->fd_lastkqfile == -1); 1425 KASSERT(newfdp->fd_knhash == NULL); 1426 KASSERT(newfdp->fd_freefile == 0); 1427 KASSERT(newfdp->fd_exclose == false); 1428 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin); 1429 KASSERT(newfdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1430 for (i = 0; i < NDFDFILE; i++) { 1431 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == 1432 (fdfile_t *)&newfdp->fd_dfdfile[i]); 1433 } 1434 for (i = NDFDFILE; i < NDFILE; i++) { 1435 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == NULL); 1436 } 1437 #endif /* DIAGNOSTIC */ 1438 1439 mutex_enter(&fdp->fd_lock); 1440 fd_checkmaps(fdp); 1441 numfiles = fdp->fd_dt->dt_nfiles; 1442 lastfile = fdp->fd_lastfile; 1443 1444 /* 1445 * If the number of open files fits in the internal arrays 1446 * of the open file structure, use them, otherwise allocate 1447 * additional memory for the number of descriptors currently 1448 * in use. 1449 */ 1450 if (lastfile < NDFILE) { 1451 i = NDFILE; 1452 newdt = newfdp->fd_dt; 1453 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin); 1454 } else { 1455 /* 1456 * Compute the smallest multiple of NDEXTENT needed 1457 * for the file descriptors currently in use, 1458 * allowing the table to shrink. 1459 */ 1460 i = numfiles; 1461 while (i >= 2 * NDEXTENT && i > lastfile * 2) { 1462 i /= 2; 1463 } 1464 KASSERT(i > NDFILE); 1465 newdt = fd_dtab_alloc(i); 1466 newfdp->fd_dt = newdt; 1467 memcpy(newdt->dt_ff, newfdp->fd_dtbuiltin.dt_ff, 1468 NDFDFILE * sizeof(fdfile_t **)); 1469 memset(newdt->dt_ff + NDFDFILE, 0, 1470 (i - NDFDFILE) * sizeof(fdfile_t **)); 1471 } 1472 if (NDHISLOTS(i) <= NDHISLOTS(NDFILE)) { 1473 newfdp->fd_himap = newfdp->fd_dhimap; 1474 newfdp->fd_lomap = newfdp->fd_dlomap; 1475 } else { 1476 fd_map_alloc(i, &newfdp->fd_lomap, &newfdp->fd_himap); 1477 KASSERT(i >= NDENTRIES * NDENTRIES); 1478 memset(newfdp->fd_himap, 0, NDHISLOTS(i)*sizeof(uint32_t)); 1479 memset(newfdp->fd_lomap, 0, NDLOSLOTS(i)*sizeof(uint32_t)); 1480 } 1481 newfdp->fd_freefile = fdp->fd_freefile; 1482 newfdp->fd_exclose = fdp->fd_exclose; 1483 1484 ffp = fdp->fd_dt->dt_ff; 1485 nffp = newdt->dt_ff; 1486 newlast = -1; 1487 for (i = 0; i <= lastfile; i++, ffp++, nffp++) { 1488 KASSERT(i >= NDFDFILE || 1489 *nffp == (fdfile_t *)newfdp->fd_dfdfile[i]); 1490 ff = *ffp; 1491 if (ff == NULL || 1492 (fp = atomic_load_consume(&ff->ff_file)) == NULL) { 1493 /* Descriptor unused, or descriptor half open. */ 1494 KASSERT(!fd_isused(newfdp, i)); 1495 continue; 1496 } 1497 if (__predict_false(fp->f_type == DTYPE_KQUEUE)) { 1498 /* kqueue descriptors cannot be copied. */ 1499 if (i < newfdp->fd_freefile) { 1500 newfdp->fd_freefile = i; 1501 } 1502 continue; 1503 } 1504 /* It's active: add a reference to the file. */ 1505 mutex_enter(&fp->f_lock); 1506 fp->f_count++; 1507 mutex_exit(&fp->f_lock); 1508 1509 /* Allocate an fdfile_t to represent it. */ 1510 if (i >= NDFDFILE) { 1511 ff2 = pool_cache_get(fdfile_cache, PR_WAITOK); 1512 *nffp = ff2; 1513 } else { 1514 ff2 = newdt->dt_ff[i]; 1515 } 1516 ff2->ff_file = fp; 1517 ff2->ff_exclose = ff->ff_exclose; 1518 ff2->ff_allocated = true; 1519 1520 /* Fix up bitmaps. */ 1521 j = i >> NDENTRYSHIFT; 1522 KASSERT((newfdp->fd_lomap[j] & (1U << (i & NDENTRYMASK))) == 0); 1523 newfdp->fd_lomap[j] |= 1U << (i & NDENTRYMASK); 1524 if (__predict_false(newfdp->fd_lomap[j] == ~0)) { 1525 KASSERT((newfdp->fd_himap[j >> NDENTRYSHIFT] & 1526 (1U << (j & NDENTRYMASK))) == 0); 1527 newfdp->fd_himap[j >> NDENTRYSHIFT] |= 1528 1U << (j & NDENTRYMASK); 1529 } 1530 newlast = i; 1531 } 1532 KASSERT(newdt->dt_ff[0] == (fdfile_t *)newfdp->fd_dfdfile[0]); 1533 newfdp->fd_lastfile = newlast; 1534 fd_checkmaps(newfdp); 1535 mutex_exit(&fdp->fd_lock); 1536 1537 return newfdp; 1538 } 1539 1540 /* 1541 * Release a filedesc structure. 1542 */ 1543 void 1544 fd_free(void) 1545 { 1546 fdfile_t *ff; 1547 file_t *fp; 1548 int fd, nf; 1549 fdtab_t *dt; 1550 lwp_t * const l = curlwp; 1551 filedesc_t * const fdp = l->l_fd; 1552 const bool noadvlock = (l->l_proc->p_flag & PK_ADVLOCK) == 0; 1553 1554 KASSERT(atomic_load_consume(&fdp->fd_dt)->dt_ff[0] == 1555 (fdfile_t *)fdp->fd_dfdfile[0]); 1556 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1557 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL); 1558 1559 membar_release(); 1560 if (atomic_dec_uint_nv(&fdp->fd_refcnt) > 0) 1561 return; 1562 membar_acquire(); 1563 1564 /* 1565 * Close any files that the process holds open. 1566 */ 1567 dt = fdp->fd_dt; 1568 fd_checkmaps(fdp); 1569 #ifdef DEBUG 1570 fdp->fd_refcnt = -1; /* see fd_checkmaps */ 1571 #endif 1572 for (fd = 0, nf = dt->dt_nfiles; fd < nf; fd++) { 1573 ff = dt->dt_ff[fd]; 1574 KASSERT(fd >= NDFDFILE || 1575 ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1576 if (ff == NULL) 1577 continue; 1578 if ((fp = atomic_load_consume(&ff->ff_file)) != NULL) { 1579 /* 1580 * Must use fd_close() here if there is 1581 * a reference from kqueue or we might have posix 1582 * advisory locks. 1583 */ 1584 if (__predict_true(ff->ff_refcnt == 0) && 1585 (noadvlock || fp->f_type != DTYPE_VNODE)) { 1586 ff->ff_file = NULL; 1587 ff->ff_exclose = false; 1588 ff->ff_allocated = false; 1589 closef(fp); 1590 } else { 1591 ff->ff_refcnt++; 1592 fd_close(fd); 1593 } 1594 } 1595 KASSERT(ff->ff_refcnt == 0); 1596 KASSERT(ff->ff_file == NULL); 1597 KASSERT(!ff->ff_exclose); 1598 KASSERT(!ff->ff_allocated); 1599 if (fd >= NDFDFILE) { 1600 pool_cache_put(fdfile_cache, ff); 1601 dt->dt_ff[fd] = NULL; 1602 } 1603 } 1604 1605 /* 1606 * Clean out the descriptor table for the next user and return 1607 * to the cache. 1608 */ 1609 if (__predict_false(dt != &fdp->fd_dtbuiltin)) { 1610 fd_dtab_free(fdp->fd_dt); 1611 /* Otherwise, done above. */ 1612 memset(&fdp->fd_dtbuiltin.dt_ff[NDFDFILE], 0, 1613 (NDFILE - NDFDFILE) * sizeof(fdp->fd_dtbuiltin.dt_ff[0])); 1614 fdp->fd_dt = &fdp->fd_dtbuiltin; 1615 } 1616 if (__predict_false(NDHISLOTS(nf) > NDHISLOTS(NDFILE))) { 1617 KASSERT(fdp->fd_himap != fdp->fd_dhimap); 1618 KASSERT(fdp->fd_lomap != fdp->fd_dlomap); 1619 fd_map_free(nf, fdp->fd_lomap, fdp->fd_himap); 1620 } 1621 if (__predict_false(fdp->fd_knhash != NULL)) { 1622 hashdone(fdp->fd_knhash, HASH_LIST, fdp->fd_knhashmask); 1623 fdp->fd_knhash = NULL; 1624 fdp->fd_knhashmask = 0; 1625 } else { 1626 KASSERT(fdp->fd_knhashmask == 0); 1627 } 1628 fdp->fd_dt = &fdp->fd_dtbuiltin; 1629 fdp->fd_lastkqfile = -1; 1630 fdp->fd_lastfile = -1; 1631 fdp->fd_freefile = 0; 1632 fdp->fd_exclose = false; 1633 memset(&fdp->fd_startzero, 0, sizeof(*fdp) - 1634 offsetof(filedesc_t, fd_startzero)); 1635 fdp->fd_himap = fdp->fd_dhimap; 1636 fdp->fd_lomap = fdp->fd_dlomap; 1637 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1638 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL); 1639 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin); 1640 #ifdef DEBUG 1641 fdp->fd_refcnt = 0; /* see fd_checkmaps */ 1642 #endif 1643 fd_checkmaps(fdp); 1644 pool_cache_put(filedesc_cache, fdp); 1645 } 1646 1647 /* 1648 * File Descriptor pseudo-device driver (/dev/fd/). 1649 * 1650 * Opening minor device N dup()s the file (if any) connected to file 1651 * descriptor N belonging to the calling process. Note that this driver 1652 * consists of only the ``open()'' routine, because all subsequent 1653 * references to this file will be direct to the other driver. 1654 */ 1655 static int 1656 filedescopen(dev_t dev, int mode, int type, lwp_t *l) 1657 { 1658 1659 /* 1660 * XXX Kludge: set dupfd to contain the value of the 1661 * the file descriptor being sought for duplication. The error 1662 * return ensures that the vnode for this device will be released 1663 * by vn_open. Open will detect this special error and take the 1664 * actions in fd_dupopen below. Other callers of vn_open or VOP_OPEN 1665 * will simply report the error. 1666 */ 1667 l->l_dupfd = minor(dev); /* XXX */ 1668 return EDUPFD; 1669 } 1670 1671 /* 1672 * Duplicate the specified descriptor to a free descriptor. 1673 * 1674 * old is the original fd. 1675 * moveit is true if we should move rather than duplicate. 1676 * flags are the open flags (converted from O_* to F*). 1677 * newp returns the new fd on success. 1678 * 1679 * These two cases are produced by the EDUPFD and EMOVEFD magic 1680 * errnos, but in the interest of removing that regrettable interface, 1681 * vn_open has been changed to intercept them. Now vn_open returns 1682 * either a vnode or a filehandle, and the filehandle is accompanied 1683 * by a boolean that says whether we should dup (moveit == false) or 1684 * move (moveit == true) the fd. 1685 * 1686 * The dup case is used by /dev/stderr, /proc/self/fd, and such. The 1687 * move case is used by cloner devices that allocate a fd of their 1688 * own (a layering violation that should go away eventually) that 1689 * then needs to be put in the place open() expects it. 1690 */ 1691 int 1692 fd_dupopen(int old, bool moveit, int flags, int *newp) 1693 { 1694 filedesc_t *fdp; 1695 fdfile_t *ff; 1696 file_t *fp; 1697 fdtab_t *dt; 1698 int error; 1699 1700 if ((fp = fd_getfile(old)) == NULL) { 1701 return EBADF; 1702 } 1703 fdp = curlwp->l_fd; 1704 dt = atomic_load_consume(&fdp->fd_dt); 1705 ff = dt->dt_ff[old]; 1706 1707 /* 1708 * There are two cases of interest here. 1709 * 1710 * 1. moveit == false (used to be the EDUPFD magic errno): 1711 * simply dup (old) to file descriptor (new) and return. 1712 * 1713 * 2. moveit == true (used to be the EMOVEFD magic errno): 1714 * steal away the file structure from (old) and store it in 1715 * (new). (old) is effectively closed by this operation. 1716 */ 1717 if (moveit == false) { 1718 /* 1719 * Check that the mode the file is being opened for is a 1720 * subset of the mode of the existing descriptor. 1721 */ 1722 if (((flags & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) { 1723 error = EACCES; 1724 goto out; 1725 } 1726 1727 /* Copy it. */ 1728 error = fd_dup(fp, 0, newp, ff->ff_exclose); 1729 } else { 1730 /* Copy it. */ 1731 error = fd_dup(fp, 0, newp, ff->ff_exclose); 1732 if (error != 0) { 1733 goto out; 1734 } 1735 1736 /* Steal away the file pointer from 'old'. */ 1737 (void)fd_close(old); 1738 return 0; 1739 } 1740 1741 out: 1742 fd_putfile(old); 1743 return error; 1744 } 1745 1746 /* 1747 * Close open files on exec. 1748 */ 1749 void 1750 fd_closeexec(void) 1751 { 1752 proc_t *p; 1753 filedesc_t *fdp; 1754 fdfile_t *ff; 1755 lwp_t *l; 1756 fdtab_t *dt; 1757 int fd; 1758 1759 l = curlwp; 1760 p = l->l_proc; 1761 fdp = p->p_fd; 1762 1763 if (fdp->fd_refcnt > 1) { 1764 fdp = fd_copy(); 1765 fd_free(); 1766 p->p_fd = fdp; 1767 l->l_fd = fdp; 1768 } 1769 if (!fdp->fd_exclose) { 1770 return; 1771 } 1772 fdp->fd_exclose = false; 1773 dt = atomic_load_consume(&fdp->fd_dt); 1774 1775 for (fd = 0; fd <= fdp->fd_lastfile; fd++) { 1776 if ((ff = dt->dt_ff[fd]) == NULL) { 1777 KASSERT(fd >= NDFDFILE); 1778 continue; 1779 } 1780 KASSERT(fd >= NDFDFILE || 1781 ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1782 if (ff->ff_file == NULL) 1783 continue; 1784 if (ff->ff_exclose) { 1785 /* 1786 * We need a reference to close the file. 1787 * No other threads can see the fdfile_t at 1788 * this point, so don't bother locking. 1789 */ 1790 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); 1791 ff->ff_refcnt++; 1792 fd_close(fd); 1793 } 1794 } 1795 } 1796 1797 /* 1798 * Sets descriptor owner. If the owner is a process, 'pgid' 1799 * is set to positive value, process ID. If the owner is process group, 1800 * 'pgid' is set to -pg_id. 1801 */ 1802 int 1803 fsetown(pid_t *pgid, u_long cmd, const void *data) 1804 { 1805 pid_t id = *(const pid_t *)data; 1806 int error; 1807 1808 if (id == INT_MIN) 1809 return EINVAL; 1810 1811 switch (cmd) { 1812 case TIOCSPGRP: 1813 if (id < 0) 1814 return EINVAL; 1815 id = -id; 1816 break; 1817 default: 1818 break; 1819 } 1820 if (id > 0) { 1821 mutex_enter(&proc_lock); 1822 error = proc_find(id) ? 0 : ESRCH; 1823 mutex_exit(&proc_lock); 1824 } else if (id < 0) { 1825 error = pgid_in_session(curproc, -id); 1826 } else { 1827 error = 0; 1828 } 1829 if (!error) { 1830 *pgid = id; 1831 } 1832 return error; 1833 } 1834 1835 void 1836 fd_set_exclose(struct lwp *l, int fd, bool exclose) 1837 { 1838 filedesc_t *fdp = l->l_fd; 1839 fdfile_t *ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd]; 1840 1841 ff->ff_exclose = exclose; 1842 if (exclose) 1843 fdp->fd_exclose = true; 1844 } 1845 1846 /* 1847 * Return descriptor owner information. If the value is positive, 1848 * it's process ID. If it's negative, it's process group ID and 1849 * needs the sign removed before use. 1850 */ 1851 int 1852 fgetown(pid_t pgid, u_long cmd, void *data) 1853 { 1854 1855 switch (cmd) { 1856 case TIOCGPGRP: 1857 *(int *)data = -pgid; 1858 break; 1859 default: 1860 *(int *)data = pgid; 1861 break; 1862 } 1863 return 0; 1864 } 1865 1866 /* 1867 * Send signal to descriptor owner, either process or process group. 1868 */ 1869 void 1870 fownsignal(pid_t pgid, int signo, int code, int band, void *fdescdata) 1871 { 1872 ksiginfo_t ksi; 1873 1874 KASSERT(!cpu_intr_p()); 1875 1876 if (pgid == 0) { 1877 return; 1878 } 1879 1880 KSI_INIT(&ksi); 1881 ksi.ksi_signo = signo; 1882 ksi.ksi_code = code; 1883 ksi.ksi_band = band; 1884 1885 mutex_enter(&proc_lock); 1886 if (pgid > 0) { 1887 struct proc *p1; 1888 1889 p1 = proc_find(pgid); 1890 if (p1 != NULL) { 1891 kpsignal(p1, &ksi, fdescdata); 1892 } 1893 } else { 1894 struct pgrp *pgrp; 1895 1896 KASSERT(pgid < 0); 1897 pgrp = pgrp_find(-pgid); 1898 if (pgrp != NULL) { 1899 kpgsignal(pgrp, &ksi, fdescdata, 0); 1900 } 1901 } 1902 mutex_exit(&proc_lock); 1903 } 1904 1905 int 1906 fd_clone(file_t *fp, unsigned fd, int flag, const struct fileops *fops, 1907 void *data) 1908 { 1909 fdfile_t *ff; 1910 filedesc_t *fdp; 1911 1912 fp->f_flag = flag & FMASK; 1913 fdp = curproc->p_fd; 1914 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd]; 1915 KASSERT(ff != NULL); 1916 ff->ff_exclose = (flag & O_CLOEXEC) != 0; 1917 fp->f_type = DTYPE_MISC; 1918 fp->f_ops = fops; 1919 fp->f_data = data; 1920 curlwp->l_dupfd = fd; 1921 fd_affix(curproc, fp, fd); 1922 1923 return EMOVEFD; 1924 } 1925 1926 int 1927 fnullop_fcntl(file_t *fp, u_int cmd, void *data) 1928 { 1929 1930 if (cmd == F_SETFL) 1931 return 0; 1932 1933 return EOPNOTSUPP; 1934 } 1935 1936 int 1937 fnullop_poll(file_t *fp, int which) 1938 { 1939 1940 return 0; 1941 } 1942 1943 int 1944 fnullop_kqfilter(file_t *fp, struct knote *kn) 1945 { 1946 1947 return EOPNOTSUPP; 1948 } 1949 1950 void 1951 fnullop_restart(file_t *fp) 1952 { 1953 1954 } 1955 1956 int 1957 fbadop_read(file_t *fp, off_t *offset, struct uio *uio, 1958 kauth_cred_t cred, int flags) 1959 { 1960 1961 return EOPNOTSUPP; 1962 } 1963 1964 int 1965 fbadop_write(file_t *fp, off_t *offset, struct uio *uio, 1966 kauth_cred_t cred, int flags) 1967 { 1968 1969 return EOPNOTSUPP; 1970 } 1971 1972 int 1973 fbadop_ioctl(file_t *fp, u_long com, void *data) 1974 { 1975 1976 return EOPNOTSUPP; 1977 } 1978 1979 int 1980 fbadop_stat(file_t *fp, struct stat *sb) 1981 { 1982 1983 return EOPNOTSUPP; 1984 } 1985 1986 int 1987 fbadop_close(file_t *fp) 1988 { 1989 1990 return EOPNOTSUPP; 1991 } 1992 1993 /* 1994 * sysctl routines pertaining to file descriptors 1995 */ 1996 1997 /* Initialized in sysctl_init() for now... */ 1998 extern kmutex_t sysctl_file_marker_lock; 1999 static u_int sysctl_file_marker = 1; 2000 2001 /* 2002 * Expects to be called with proc_lock and sysctl_file_marker_lock locked. 2003 */ 2004 static void 2005 sysctl_file_marker_reset(void) 2006 { 2007 struct proc *p; 2008 2009 PROCLIST_FOREACH(p, &allproc) { 2010 struct filedesc *fd = p->p_fd; 2011 fdtab_t *dt; 2012 u_int i; 2013 2014 mutex_enter(&fd->fd_lock); 2015 dt = fd->fd_dt; 2016 for (i = 0; i < dt->dt_nfiles; i++) { 2017 struct file *fp; 2018 fdfile_t *ff; 2019 2020 if ((ff = dt->dt_ff[i]) == NULL) { 2021 continue; 2022 } 2023 if ((fp = atomic_load_consume(&ff->ff_file)) == NULL) { 2024 continue; 2025 } 2026 fp->f_marker = 0; 2027 } 2028 mutex_exit(&fd->fd_lock); 2029 } 2030 } 2031 2032 /* 2033 * sysctl helper routine for kern.file pseudo-subtree. 2034 */ 2035 static int 2036 sysctl_kern_file(SYSCTLFN_ARGS) 2037 { 2038 const bool allowaddr = get_expose_address(curproc); 2039 struct filelist flist; 2040 int error; 2041 size_t buflen; 2042 struct file *fp, fbuf; 2043 char *start, *where; 2044 struct proc *p; 2045 2046 start = where = oldp; 2047 buflen = *oldlenp; 2048 2049 if (where == NULL) { 2050 /* 2051 * overestimate by 10 files 2052 */ 2053 *oldlenp = sizeof(filehead) + (nfiles + 10) * 2054 sizeof(struct file); 2055 return 0; 2056 } 2057 2058 /* 2059 * first sysctl_copyout filehead 2060 */ 2061 if (buflen < sizeof(filehead)) { 2062 *oldlenp = 0; 2063 return 0; 2064 } 2065 sysctl_unlock(); 2066 if (allowaddr) { 2067 memcpy(&flist, &filehead, sizeof(flist)); 2068 } else { 2069 memset(&flist, 0, sizeof(flist)); 2070 } 2071 error = sysctl_copyout(l, &flist, where, sizeof(flist)); 2072 if (error) { 2073 sysctl_relock(); 2074 return error; 2075 } 2076 buflen -= sizeof(flist); 2077 where += sizeof(flist); 2078 2079 /* 2080 * followed by an array of file structures 2081 */ 2082 mutex_enter(&sysctl_file_marker_lock); 2083 mutex_enter(&proc_lock); 2084 PROCLIST_FOREACH(p, &allproc) { 2085 struct filedesc *fd; 2086 fdtab_t *dt; 2087 u_int i; 2088 2089 if (p->p_stat == SIDL) { 2090 /* skip embryonic processes */ 2091 continue; 2092 } 2093 mutex_enter(p->p_lock); 2094 error = kauth_authorize_process(l->l_cred, 2095 KAUTH_PROCESS_CANSEE, p, 2096 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES), 2097 NULL, NULL); 2098 mutex_exit(p->p_lock); 2099 if (error != 0) { 2100 /* 2101 * Don't leak kauth retval if we're silently 2102 * skipping this entry. 2103 */ 2104 error = 0; 2105 continue; 2106 } 2107 2108 /* 2109 * Grab a hold on the process. 2110 */ 2111 if (!rw_tryenter(&p->p_reflock, RW_READER)) { 2112 continue; 2113 } 2114 mutex_exit(&proc_lock); 2115 2116 fd = p->p_fd; 2117 mutex_enter(&fd->fd_lock); 2118 dt = fd->fd_dt; 2119 for (i = 0; i < dt->dt_nfiles; i++) { 2120 fdfile_t *ff; 2121 2122 if ((ff = dt->dt_ff[i]) == NULL) { 2123 continue; 2124 } 2125 if ((fp = atomic_load_consume(&ff->ff_file)) == NULL) { 2126 continue; 2127 } 2128 2129 mutex_enter(&fp->f_lock); 2130 2131 if ((fp->f_count == 0) || 2132 (fp->f_marker == sysctl_file_marker)) { 2133 mutex_exit(&fp->f_lock); 2134 continue; 2135 } 2136 2137 /* Check that we have enough space. */ 2138 if (buflen < sizeof(struct file)) { 2139 *oldlenp = where - start; 2140 mutex_exit(&fp->f_lock); 2141 error = ENOMEM; 2142 break; 2143 } 2144 2145 fill_file(&fbuf, fp); 2146 mutex_exit(&fp->f_lock); 2147 error = sysctl_copyout(l, &fbuf, where, sizeof(fbuf)); 2148 if (error) { 2149 break; 2150 } 2151 buflen -= sizeof(struct file); 2152 where += sizeof(struct file); 2153 2154 fp->f_marker = sysctl_file_marker; 2155 } 2156 mutex_exit(&fd->fd_lock); 2157 2158 /* 2159 * Release reference to process. 2160 */ 2161 mutex_enter(&proc_lock); 2162 rw_exit(&p->p_reflock); 2163 2164 if (error) 2165 break; 2166 } 2167 2168 sysctl_file_marker++; 2169 /* Reset all markers if wrapped. */ 2170 if (sysctl_file_marker == 0) { 2171 sysctl_file_marker_reset(); 2172 sysctl_file_marker++; 2173 } 2174 2175 mutex_exit(&proc_lock); 2176 mutex_exit(&sysctl_file_marker_lock); 2177 2178 *oldlenp = where - start; 2179 sysctl_relock(); 2180 return error; 2181 } 2182 2183 /* 2184 * sysctl helper function for kern.file2 2185 */ 2186 static int 2187 sysctl_kern_file2(SYSCTLFN_ARGS) 2188 { 2189 struct proc *p; 2190 struct file *fp; 2191 struct filedesc *fd; 2192 struct kinfo_file kf; 2193 char *dp; 2194 u_int i, op; 2195 size_t len, needed, elem_size, out_size; 2196 int error, arg, elem_count; 2197 fdfile_t *ff; 2198 fdtab_t *dt; 2199 2200 if (namelen == 1 && name[0] == CTL_QUERY) 2201 return sysctl_query(SYSCTLFN_CALL(rnode)); 2202 2203 if (namelen != 4) 2204 return EINVAL; 2205 2206 error = 0; 2207 dp = oldp; 2208 len = (oldp != NULL) ? *oldlenp : 0; 2209 op = name[0]; 2210 arg = name[1]; 2211 elem_size = name[2]; 2212 elem_count = name[3]; 2213 out_size = MIN(sizeof(kf), elem_size); 2214 needed = 0; 2215 2216 if (elem_size < 1 || elem_count < 0) 2217 return EINVAL; 2218 2219 switch (op) { 2220 case KERN_FILE_BYFILE: 2221 case KERN_FILE_BYPID: 2222 /* 2223 * We're traversing the process list in both cases; the BYFILE 2224 * case does additional work of keeping track of files already 2225 * looked at. 2226 */ 2227 2228 /* doesn't use arg so it must be zero */ 2229 if ((op == KERN_FILE_BYFILE) && (arg != 0)) 2230 return EINVAL; 2231 2232 if ((op == KERN_FILE_BYPID) && (arg < -1)) 2233 /* -1 means all processes */ 2234 return EINVAL; 2235 2236 sysctl_unlock(); 2237 if (op == KERN_FILE_BYFILE) 2238 mutex_enter(&sysctl_file_marker_lock); 2239 mutex_enter(&proc_lock); 2240 PROCLIST_FOREACH(p, &allproc) { 2241 if (p->p_stat == SIDL) { 2242 /* skip embryonic processes */ 2243 continue; 2244 } 2245 if (arg > 0 && p->p_pid != arg) { 2246 /* pick only the one we want */ 2247 /* XXX want 0 to mean "kernel files" */ 2248 continue; 2249 } 2250 mutex_enter(p->p_lock); 2251 error = kauth_authorize_process(l->l_cred, 2252 KAUTH_PROCESS_CANSEE, p, 2253 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES), 2254 NULL, NULL); 2255 mutex_exit(p->p_lock); 2256 if (error != 0) { 2257 /* 2258 * Don't leak kauth retval if we're silently 2259 * skipping this entry. 2260 */ 2261 error = 0; 2262 continue; 2263 } 2264 2265 /* 2266 * Grab a hold on the process. 2267 */ 2268 if (!rw_tryenter(&p->p_reflock, RW_READER)) { 2269 continue; 2270 } 2271 mutex_exit(&proc_lock); 2272 2273 fd = p->p_fd; 2274 mutex_enter(&fd->fd_lock); 2275 dt = fd->fd_dt; 2276 for (i = 0; i < dt->dt_nfiles; i++) { 2277 if ((ff = dt->dt_ff[i]) == NULL) { 2278 continue; 2279 } 2280 if ((fp = atomic_load_consume(&ff->ff_file)) == 2281 NULL) { 2282 continue; 2283 } 2284 2285 if ((op == KERN_FILE_BYFILE) && 2286 (fp->f_marker == sysctl_file_marker)) { 2287 continue; 2288 } 2289 if (len >= elem_size && elem_count > 0) { 2290 mutex_enter(&fp->f_lock); 2291 fill_file2(&kf, fp, ff, i, p->p_pid); 2292 mutex_exit(&fp->f_lock); 2293 mutex_exit(&fd->fd_lock); 2294 error = sysctl_copyout(l, 2295 &kf, dp, out_size); 2296 mutex_enter(&fd->fd_lock); 2297 if (error) 2298 break; 2299 dp += elem_size; 2300 len -= elem_size; 2301 } 2302 if (op == KERN_FILE_BYFILE) 2303 fp->f_marker = sysctl_file_marker; 2304 needed += elem_size; 2305 if (elem_count > 0 && elem_count != INT_MAX) 2306 elem_count--; 2307 } 2308 mutex_exit(&fd->fd_lock); 2309 2310 /* 2311 * Release reference to process. 2312 */ 2313 mutex_enter(&proc_lock); 2314 rw_exit(&p->p_reflock); 2315 } 2316 if (op == KERN_FILE_BYFILE) { 2317 sysctl_file_marker++; 2318 2319 /* Reset all markers if wrapped. */ 2320 if (sysctl_file_marker == 0) { 2321 sysctl_file_marker_reset(); 2322 sysctl_file_marker++; 2323 } 2324 } 2325 mutex_exit(&proc_lock); 2326 if (op == KERN_FILE_BYFILE) 2327 mutex_exit(&sysctl_file_marker_lock); 2328 sysctl_relock(); 2329 break; 2330 default: 2331 return EINVAL; 2332 } 2333 2334 if (oldp == NULL) 2335 needed += KERN_FILESLOP * elem_size; 2336 *oldlenp = needed; 2337 2338 return error; 2339 } 2340 2341 static void 2342 fill_file(struct file *fp, const struct file *fpsrc) 2343 { 2344 const bool allowaddr = get_expose_address(curproc); 2345 2346 memset(fp, 0, sizeof(*fp)); 2347 2348 fp->f_offset = fpsrc->f_offset; 2349 COND_SET_PTR(fp->f_cred, fpsrc->f_cred, allowaddr); 2350 COND_SET_CPTR(fp->f_ops, fpsrc->f_ops, allowaddr); 2351 COND_SET_STRUCT(fp->f_undata, fpsrc->f_undata, allowaddr); 2352 COND_SET_STRUCT(fp->f_list, fpsrc->f_list, allowaddr); 2353 fp->f_flag = fpsrc->f_flag; 2354 fp->f_marker = fpsrc->f_marker; 2355 fp->f_type = fpsrc->f_type; 2356 fp->f_advice = fpsrc->f_advice; 2357 fp->f_count = fpsrc->f_count; 2358 fp->f_msgcount = fpsrc->f_msgcount; 2359 fp->f_unpcount = fpsrc->f_unpcount; 2360 COND_SET_STRUCT(fp->f_unplist, fpsrc->f_unplist, allowaddr); 2361 } 2362 2363 static void 2364 fill_file2(struct kinfo_file *kp, const file_t *fp, const fdfile_t *ff, 2365 int i, pid_t pid) 2366 { 2367 const bool allowaddr = get_expose_address(curproc); 2368 2369 memset(kp, 0, sizeof(*kp)); 2370 2371 COND_SET_VALUE(kp->ki_fileaddr, PTRTOUINT64(fp), allowaddr); 2372 kp->ki_flag = fp->f_flag; 2373 kp->ki_iflags = 0; 2374 kp->ki_ftype = fp->f_type; 2375 kp->ki_count = fp->f_count; 2376 kp->ki_msgcount = fp->f_msgcount; 2377 COND_SET_VALUE(kp->ki_fucred, PTRTOUINT64(fp->f_cred), allowaddr); 2378 kp->ki_fuid = kauth_cred_geteuid(fp->f_cred); 2379 kp->ki_fgid = kauth_cred_getegid(fp->f_cred); 2380 COND_SET_VALUE(kp->ki_fops, PTRTOUINT64(fp->f_ops), allowaddr); 2381 kp->ki_foffset = fp->f_offset; 2382 COND_SET_VALUE(kp->ki_fdata, PTRTOUINT64(fp->f_data), allowaddr); 2383 2384 /* vnode information to glue this file to something */ 2385 if (fp->f_type == DTYPE_VNODE) { 2386 struct vnode *vp = fp->f_vnode; 2387 2388 COND_SET_VALUE(kp->ki_vun, PTRTOUINT64(vp->v_un.vu_socket), 2389 allowaddr); 2390 kp->ki_vsize = vp->v_size; 2391 kp->ki_vtype = vp->v_type; 2392 kp->ki_vtag = vp->v_tag; 2393 COND_SET_VALUE(kp->ki_vdata, PTRTOUINT64(vp->v_data), 2394 allowaddr); 2395 } 2396 2397 /* process information when retrieved via KERN_FILE_BYPID */ 2398 if (ff != NULL) { 2399 kp->ki_pid = pid; 2400 kp->ki_fd = i; 2401 kp->ki_ofileflags = ff->ff_exclose; 2402 kp->ki_usecount = ff->ff_refcnt; 2403 } 2404 } 2405