1 /* $NetBSD: kern_descrip.c,v 1.264 2024/11/10 00:11:43 kre Exp $ */ 2 3 /*- 4 * Copyright (c) 2008, 2009, 2023 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 1.264 2024/11/10 00:11:43 kre 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; 109 110 static int file_ctor(void *, void *, int); 111 static void file_dtor(void *, void *); 112 static void fdfile_ctor(fdfile_t *); 113 static void fdfile_dtor(fdfile_t *); 114 static int filedesc_ctor(void *, void *, int); 115 static void filedesc_dtor(void *, void *); 116 static int filedescopen(dev_t, int, int, lwp_t *); 117 118 static int sysctl_kern_file(SYSCTLFN_PROTO); 119 static int sysctl_kern_file2(SYSCTLFN_PROTO); 120 static void fill_file(struct file *, const struct file *); 121 static void fill_file2(struct kinfo_file *, const file_t *, const fdfile_t *, 122 int, pid_t); 123 124 const struct cdevsw filedesc_cdevsw = { 125 .d_open = filedescopen, 126 .d_close = noclose, 127 .d_read = noread, 128 .d_write = nowrite, 129 .d_ioctl = noioctl, 130 .d_stop = nostop, 131 .d_tty = notty, 132 .d_poll = nopoll, 133 .d_mmap = nommap, 134 .d_kqfilter = nokqfilter, 135 .d_discard = nodiscard, 136 .d_flag = D_OTHER | D_MPSAFE 137 }; 138 139 /* For ease of reading. */ 140 __strong_alias(fd_putvnode,fd_putfile) 141 __strong_alias(fd_putsock,fd_putfile) 142 143 /* 144 * Initialize the descriptor system. 145 */ 146 void 147 fd_sys_init(void) 148 { 149 static struct sysctllog *clog; 150 151 mutex_init(&filelist_lock, MUTEX_DEFAULT, IPL_NONE); 152 153 LIST_INIT(&filehead); 154 155 file_cache = pool_cache_init(sizeof(file_t), coherency_unit, 0, 156 0, "file", NULL, IPL_NONE, file_ctor, file_dtor, NULL); 157 KASSERT(file_cache != NULL); 158 159 filedesc_cache = pool_cache_init(sizeof(filedesc_t), coherency_unit, 160 0, 0, "filedesc", NULL, IPL_NONE, filedesc_ctor, filedesc_dtor, 161 NULL); 162 KASSERT(filedesc_cache != NULL); 163 164 sysctl_createv(&clog, 0, NULL, NULL, 165 CTLFLAG_PERMANENT, 166 CTLTYPE_STRUCT, "file", 167 SYSCTL_DESCR("System open file table"), 168 sysctl_kern_file, 0, NULL, 0, 169 CTL_KERN, KERN_FILE, CTL_EOL); 170 sysctl_createv(&clog, 0, NULL, NULL, 171 CTLFLAG_PERMANENT, 172 CTLTYPE_STRUCT, "file2", 173 SYSCTL_DESCR("System open file table"), 174 sysctl_kern_file2, 0, NULL, 0, 175 CTL_KERN, KERN_FILE2, CTL_EOL); 176 } 177 178 static bool 179 fd_isused(filedesc_t *fdp, unsigned fd) 180 { 181 u_int off = fd >> NDENTRYSHIFT; 182 183 KASSERT(fd < atomic_load_consume(&fdp->fd_dt)->dt_nfiles); 184 185 return (fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) != 0; 186 } 187 188 /* 189 * Verify that the bitmaps match the descriptor table. 190 */ 191 static inline void 192 fd_checkmaps(filedesc_t *fdp) 193 { 194 #ifdef DEBUG 195 fdtab_t *dt; 196 u_int fd; 197 198 KASSERT(fdp->fd_refcnt <= 1 || mutex_owned(&fdp->fd_lock)); 199 200 dt = fdp->fd_dt; 201 if (fdp->fd_refcnt == -1) { 202 /* 203 * fd_free tears down the table without maintaining its bitmap. 204 */ 205 return; 206 } 207 for (fd = 0; fd < dt->dt_nfiles; fd++) { 208 if (fd < NDFDFILE) { 209 KASSERT(dt->dt_ff[fd] == 210 (fdfile_t *)fdp->fd_dfdfile[fd]); 211 } 212 if (dt->dt_ff[fd] == NULL) { 213 KASSERT(!fd_isused(fdp, fd)); 214 } else if (dt->dt_ff[fd]->ff_file != NULL) { 215 KASSERT(fd_isused(fdp, fd)); 216 } 217 } 218 #endif 219 } 220 221 static int 222 fd_next_zero(filedesc_t *fdp, uint32_t *bitmap, int want, u_int bits) 223 { 224 int i, off, maxoff; 225 uint32_t sub; 226 227 KASSERT(mutex_owned(&fdp->fd_lock)); 228 229 fd_checkmaps(fdp); 230 231 if (want > bits) 232 return -1; 233 234 off = want >> NDENTRYSHIFT; 235 i = want & NDENTRYMASK; 236 if (i) { 237 sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i)); 238 if (sub != ~0) 239 goto found; 240 off++; 241 } 242 243 maxoff = NDLOSLOTS(bits); 244 while (off < maxoff) { 245 if ((sub = bitmap[off]) != ~0) 246 goto found; 247 off++; 248 } 249 250 return -1; 251 252 found: 253 return (off << NDENTRYSHIFT) + ffs(~sub) - 1; 254 } 255 256 static int 257 fd_last_set(filedesc_t *fd, int last) 258 { 259 int off, i; 260 fdfile_t **ff = fd->fd_dt->dt_ff; 261 uint32_t *bitmap = fd->fd_lomap; 262 263 KASSERT(mutex_owned(&fd->fd_lock)); 264 265 fd_checkmaps(fd); 266 267 off = (last - 1) >> NDENTRYSHIFT; 268 269 while (off >= 0 && !bitmap[off]) 270 off--; 271 272 if (off < 0) 273 return -1; 274 275 i = ((off + 1) << NDENTRYSHIFT) - 1; 276 if (i >= last) 277 i = last - 1; 278 279 /* XXX should use bitmap */ 280 while (i > 0 && (ff[i] == NULL || !ff[i]->ff_allocated)) 281 i--; 282 283 return i; 284 } 285 286 static inline void 287 fd_used(filedesc_t *fdp, unsigned fd) 288 { 289 u_int off = fd >> NDENTRYSHIFT; 290 fdfile_t *ff; 291 292 ff = fdp->fd_dt->dt_ff[fd]; 293 294 KASSERT(mutex_owned(&fdp->fd_lock)); 295 KASSERT((fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) == 0); 296 KASSERT(ff != NULL); 297 KASSERT(ff->ff_file == NULL); 298 KASSERT(!ff->ff_allocated); 299 300 ff->ff_allocated = true; 301 fdp->fd_lomap[off] |= 1U << (fd & NDENTRYMASK); 302 if (__predict_false(fdp->fd_lomap[off] == ~0)) { 303 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & 304 (1U << (off & NDENTRYMASK))) == 0); 305 fdp->fd_himap[off >> NDENTRYSHIFT] |= 1U << (off & NDENTRYMASK); 306 } 307 308 if ((int)fd > fdp->fd_lastfile) { 309 fdp->fd_lastfile = fd; 310 } 311 312 fd_checkmaps(fdp); 313 } 314 315 static inline void 316 fd_unused(filedesc_t *fdp, unsigned fd) 317 { 318 u_int off = fd >> NDENTRYSHIFT; 319 fdfile_t *ff; 320 321 ff = fdp->fd_dt->dt_ff[fd]; 322 323 KASSERT(mutex_owned(&fdp->fd_lock)); 324 KASSERT(ff != NULL); 325 KASSERT(ff->ff_file == NULL); 326 KASSERT(ff->ff_allocated); 327 328 if (fd < fdp->fd_freefile) { 329 fdp->fd_freefile = fd; 330 } 331 332 if (fdp->fd_lomap[off] == ~0) { 333 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & 334 (1U << (off & NDENTRYMASK))) != 0); 335 fdp->fd_himap[off >> NDENTRYSHIFT] &= 336 ~(1U << (off & NDENTRYMASK)); 337 } 338 KASSERT((fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) != 0); 339 fdp->fd_lomap[off] &= ~(1U << (fd & NDENTRYMASK)); 340 ff->ff_allocated = false; 341 342 KASSERT(fd <= fdp->fd_lastfile); 343 if (fd == fdp->fd_lastfile) { 344 fdp->fd_lastfile = fd_last_set(fdp, fd); 345 } 346 fd_checkmaps(fdp); 347 } 348 349 /* 350 * Look up the file structure corresponding to a file descriptor 351 * and return the file, holding a reference on the descriptor. 352 */ 353 file_t * 354 fd_getfile(unsigned fd) 355 { 356 filedesc_t *fdp; 357 fdfile_t *ff; 358 file_t *fp; 359 fdtab_t *dt; 360 361 /* 362 * Look up the fdfile structure representing this descriptor. 363 * We are doing this unlocked. See fd_tryexpand(). 364 */ 365 fdp = curlwp->l_fd; 366 dt = atomic_load_consume(&fdp->fd_dt); 367 if (__predict_false(fd >= dt->dt_nfiles)) { 368 return NULL; 369 } 370 ff = dt->dt_ff[fd]; 371 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 372 if (__predict_false(ff == NULL)) { 373 return NULL; 374 } 375 376 /* Now get a reference to the descriptor. */ 377 if (fdp->fd_refcnt == 1) { 378 /* 379 * Single threaded: don't need to worry about concurrent 380 * access (other than earlier calls to kqueue, which may 381 * hold a reference to the descriptor). 382 */ 383 ff->ff_refcnt++; 384 } else { 385 /* 386 * Multi threaded: issue a memory barrier to ensure that we 387 * acquire the file pointer _after_ adding a reference. If 388 * no memory barrier, we could fetch a stale pointer. 389 * 390 * In particular, we must coordinate the following four 391 * memory operations: 392 * 393 * A. fd_close store ff->ff_file = NULL 394 * B. fd_close refcnt = atomic_dec_uint_nv(&ff->ff_refcnt) 395 * C. fd_getfile atomic_inc_uint(&ff->ff_refcnt) 396 * D. fd_getfile load fp = ff->ff_file 397 * 398 * If the order is D;A;B;C: 399 * 400 * 1. D: fp = ff->ff_file 401 * 2. A: ff->ff_file = NULL 402 * 3. B: refcnt = atomic_dec_uint_nv(&ff->ff_refcnt) 403 * 4. C: atomic_inc_uint(&ff->ff_refcnt) 404 * 405 * then fd_close determines that there are no more 406 * references and decides to free fp immediately, at 407 * the same that fd_getfile ends up with an fp that's 408 * about to be freed. *boom* 409 * 410 * By making B a release operation in fd_close, and by 411 * making C an acquire operation in fd_getfile, since 412 * they are atomic operations on the same object, which 413 * has a total modification order, we guarantee either: 414 * 415 * - B happens before C. Then since A is 416 * sequenced before B in fd_close, and C is 417 * sequenced before D in fd_getfile, we 418 * guarantee A happens before D, so fd_getfile 419 * reads a null fp and safely fails. 420 * 421 * - C happens before B. Then fd_getfile may read 422 * null or nonnull, but either way, fd_close 423 * will safely wait for references to drain. 424 */ 425 atomic_inc_uint(&ff->ff_refcnt); 426 membar_acquire(); 427 } 428 429 /* 430 * If the file is not open or is being closed then put the 431 * reference back. 432 */ 433 fp = atomic_load_consume(&ff->ff_file); 434 if (__predict_true(fp != NULL)) { 435 return fp; 436 } 437 fd_putfile(fd); 438 return NULL; 439 } 440 441 /* 442 * Release a reference to a file descriptor acquired with fd_getfile(). 443 */ 444 void 445 fd_putfile(unsigned fd) 446 { 447 filedesc_t *fdp; 448 fdfile_t *ff; 449 u_int u, v; 450 451 fdp = curlwp->l_fd; 452 KASSERT(fd < atomic_load_consume(&fdp->fd_dt)->dt_nfiles); 453 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd]; 454 455 KASSERT(ff != NULL); 456 KASSERT((ff->ff_refcnt & FR_MASK) > 0); 457 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 458 459 if (fdp->fd_refcnt == 1) { 460 /* 461 * Single threaded: don't need to worry about concurrent 462 * access (other than earlier calls to kqueue, which may 463 * hold a reference to the descriptor). 464 */ 465 if (__predict_false((ff->ff_refcnt & FR_CLOSING) != 0)) { 466 fd_close(fd); 467 return; 468 } 469 ff->ff_refcnt--; 470 return; 471 } 472 473 /* 474 * Ensure that any use of the file is complete and globally 475 * visible before dropping the final reference. If no membar, 476 * the current CPU could still access memory associated with 477 * the file after it has been freed or recycled by another 478 * CPU. 479 */ 480 membar_release(); 481 482 /* 483 * Be optimistic and start out with the assumption that no other 484 * threads are trying to close the descriptor. If the CAS fails, 485 * we lost a race and/or it's being closed. 486 */ 487 for (u = ff->ff_refcnt & FR_MASK;; u = v) { 488 v = atomic_cas_uint(&ff->ff_refcnt, u, u - 1); 489 if (__predict_true(u == v)) { 490 return; 491 } 492 if (__predict_false((v & FR_CLOSING) != 0)) { 493 break; 494 } 495 } 496 497 /* Another thread is waiting to close the file: join it. */ 498 (void)fd_close(fd); 499 } 500 501 /* 502 * Convenience wrapper around fd_getfile() that returns reference 503 * to a vnode. 504 */ 505 int 506 fd_getvnode(unsigned fd, file_t **fpp) 507 { 508 vnode_t *vp; 509 file_t *fp; 510 511 fp = fd_getfile(fd); 512 if (__predict_false(fp == NULL)) { 513 return EBADF; 514 } 515 if (__predict_false(fp->f_type != DTYPE_VNODE)) { 516 fd_putfile(fd); 517 return EINVAL; 518 } 519 vp = fp->f_vnode; 520 if (__predict_false(vp->v_type == VBAD)) { 521 /* XXX Is this case really necessary? */ 522 fd_putfile(fd); 523 return EBADF; 524 } 525 *fpp = fp; 526 return 0; 527 } 528 529 /* 530 * Convenience wrapper around fd_getfile() that returns reference 531 * to a socket. 532 */ 533 int 534 fd_getsock1(unsigned fd, struct socket **sop, file_t **fp) 535 { 536 *fp = fd_getfile(fd); 537 if (__predict_false(*fp == NULL)) { 538 return EBADF; 539 } 540 if (__predict_false((*fp)->f_type != DTYPE_SOCKET)) { 541 fd_putfile(fd); 542 return ENOTSOCK; 543 } 544 *sop = (*fp)->f_socket; 545 return 0; 546 } 547 548 int 549 fd_getsock(unsigned fd, struct socket **sop) 550 { 551 file_t *fp; 552 return fd_getsock1(fd, sop, &fp); 553 } 554 555 /* 556 * Look up the file structure corresponding to a file descriptor 557 * and return it with a reference held on the file, not the 558 * descriptor. 559 * 560 * This is heavyweight and only used when accessing descriptors 561 * from a foreign process. The caller must ensure that `p' does 562 * not exit or fork across this call. 563 * 564 * To release the file (not descriptor) reference, use closef(). 565 */ 566 file_t * 567 fd_getfile2(proc_t *p, unsigned fd) 568 { 569 filedesc_t *fdp; 570 fdfile_t *ff; 571 file_t *fp; 572 fdtab_t *dt; 573 574 fdp = p->p_fd; 575 mutex_enter(&fdp->fd_lock); 576 dt = fdp->fd_dt; 577 if (fd >= dt->dt_nfiles) { 578 mutex_exit(&fdp->fd_lock); 579 return NULL; 580 } 581 if ((ff = dt->dt_ff[fd]) == NULL) { 582 mutex_exit(&fdp->fd_lock); 583 return NULL; 584 } 585 if ((fp = atomic_load_consume(&ff->ff_file)) == NULL) { 586 mutex_exit(&fdp->fd_lock); 587 return NULL; 588 } 589 mutex_enter(&fp->f_lock); 590 fp->f_count++; 591 mutex_exit(&fp->f_lock); 592 mutex_exit(&fdp->fd_lock); 593 594 return fp; 595 } 596 597 /* 598 * Internal form of close. Must be called with a reference to the 599 * descriptor, and will drop the reference. When all descriptor 600 * references are dropped, releases the descriptor slot and a single 601 * reference to the file structure. 602 */ 603 int 604 fd_close(unsigned fd) 605 { 606 struct flock lf; 607 filedesc_t *fdp; 608 fdfile_t *ff; 609 file_t *fp; 610 proc_t *p; 611 lwp_t *l; 612 u_int refcnt; 613 614 l = curlwp; 615 p = l->l_proc; 616 fdp = l->l_fd; 617 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd]; 618 619 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 620 621 mutex_enter(&fdp->fd_lock); 622 KASSERT((ff->ff_refcnt & FR_MASK) > 0); 623 fp = atomic_load_consume(&ff->ff_file); 624 if (__predict_false(fp == NULL)) { 625 /* 626 * Another user of the file is already closing, and is 627 * waiting for other users of the file to drain. Release 628 * our reference, and wake up the closer. 629 */ 630 membar_release(); 631 atomic_dec_uint(&ff->ff_refcnt); 632 cv_broadcast(&ff->ff_closing); 633 mutex_exit(&fdp->fd_lock); 634 635 /* 636 * An application error, so pretend that the descriptor 637 * was already closed. We can't safely wait for it to 638 * be closed without potentially deadlocking. 639 */ 640 return (EBADF); 641 } 642 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); 643 644 /* 645 * There may be multiple users of this file within the process. 646 * Notify existing and new users that the file is closing. This 647 * will prevent them from adding additional uses to this file 648 * while we are closing it. 649 */ 650 atomic_store_relaxed(&ff->ff_file, NULL); 651 ff->ff_exclose = false; 652 653 /* 654 * We expect the caller to hold a descriptor reference - drop it. 655 * The reference count may increase beyond zero at this point due 656 * to an erroneous descriptor reference by an application, but 657 * fd_getfile() will notice that the file is being closed and drop 658 * the reference again. 659 */ 660 if (fdp->fd_refcnt == 1) { 661 /* Single threaded. */ 662 refcnt = --(ff->ff_refcnt); 663 } else { 664 /* Multi threaded. */ 665 membar_release(); 666 refcnt = atomic_dec_uint_nv(&ff->ff_refcnt); 667 membar_acquire(); 668 } 669 if (__predict_false(refcnt != 0)) { 670 /* 671 * Wait for other references to drain. This is typically 672 * an application error - the descriptor is being closed 673 * while still in use. 674 * (Or just a threaded application trying to unblock its 675 * thread that sleeps in (say) accept()). 676 */ 677 atomic_or_uint(&ff->ff_refcnt, FR_CLOSING); 678 679 /* 680 * Remove any knotes attached to the file. A knote 681 * attached to the descriptor can hold references on it. 682 */ 683 mutex_exit(&fdp->fd_lock); 684 if (!SLIST_EMPTY(&ff->ff_knlist)) { 685 knote_fdclose(fd); 686 } 687 688 /* 689 * Since the file system code doesn't know which fd 690 * each request came from (think dup()), we have to 691 * ask it to return ERESTART for any long-term blocks. 692 * The re-entry through read/write/etc will detect the 693 * closed fd and return EBAFD. 694 * Blocked partial writes may return a short length. 695 */ 696 (*fp->f_ops->fo_restart)(fp); 697 mutex_enter(&fdp->fd_lock); 698 699 /* 700 * We need to see the count drop to zero at least once, 701 * in order to ensure that all pre-existing references 702 * have been drained. New references past this point are 703 * of no interest. 704 * XXX (dsl) this may need to call fo_restart() after a 705 * timeout to guarantee that all the system calls exit. 706 */ 707 while ((ff->ff_refcnt & FR_MASK) != 0) { 708 cv_wait(&ff->ff_closing, &fdp->fd_lock); 709 } 710 atomic_and_uint(&ff->ff_refcnt, ~FR_CLOSING); 711 } else { 712 /* If no references, there must be no knotes. */ 713 KASSERT(SLIST_EMPTY(&ff->ff_knlist)); 714 } 715 716 /* 717 * POSIX record locking dictates that any close releases ALL 718 * locks owned by this process. This is handled by setting 719 * a flag in the unlock to free ONLY locks obeying POSIX 720 * semantics, and not to free BSD-style file locks. 721 * If the descriptor was in a message, POSIX-style locks 722 * aren't passed with the descriptor. 723 */ 724 if (__predict_false((p->p_flag & PK_ADVLOCK) != 0) && 725 fp->f_ops->fo_advlock != NULL) { 726 lf.l_whence = SEEK_SET; 727 lf.l_start = 0; 728 lf.l_len = 0; 729 lf.l_type = F_UNLCK; 730 mutex_exit(&fdp->fd_lock); 731 (void)(*fp->f_ops->fo_advlock)(fp, p, F_UNLCK, &lf, F_POSIX); 732 mutex_enter(&fdp->fd_lock); 733 } 734 735 /* Free descriptor slot. */ 736 fd_unused(fdp, fd); 737 mutex_exit(&fdp->fd_lock); 738 739 /* Now drop reference to the file itself. */ 740 return closef(fp); 741 } 742 743 /* 744 * Duplicate a file descriptor. 745 */ 746 int 747 fd_dup(file_t *fp, int minfd, int *newp, bool exclose) 748 { 749 proc_t *p = curproc; 750 int error; 751 752 while ((error = fd_alloc(p, minfd, newp)) != 0) { 753 if (error != ENOSPC) { 754 return error; 755 } 756 fd_tryexpand(p); 757 } 758 759 fd_set_exclose(curlwp, *newp, exclose); 760 fd_affix(p, fp, *newp); 761 return 0; 762 } 763 764 /* 765 * dup2 operation. 766 */ 767 int 768 fd_dup2(file_t *fp, unsigned newfd, int flags) 769 { 770 filedesc_t *fdp = curlwp->l_fd; 771 fdfile_t *ff; 772 fdtab_t *dt; 773 774 if (flags & ~(O_CLOEXEC|O_NONBLOCK|O_NOSIGPIPE)) 775 return EINVAL; 776 /* 777 * Ensure there are enough slots in the descriptor table, 778 * and allocate an fdfile_t up front in case we need it. 779 */ 780 while (newfd >= atomic_load_consume(&fdp->fd_dt)->dt_nfiles) { 781 fd_tryexpand(curproc); 782 } 783 ff = kmem_alloc(sizeof(*ff), KM_SLEEP); 784 fdfile_ctor(ff); 785 786 /* 787 * If there is already a file open, close it. If the file is 788 * half open, wait for it to be constructed before closing it. 789 * XXX Potential for deadlock here? 790 */ 791 mutex_enter(&fdp->fd_lock); 792 while (fd_isused(fdp, newfd)) { 793 mutex_exit(&fdp->fd_lock); 794 if (fd_getfile(newfd) != NULL) { 795 (void)fd_close(newfd); 796 } else { 797 /* 798 * Crummy, but unlikely to happen. 799 * Can occur if we interrupt another 800 * thread while it is opening a file. 801 */ 802 kpause("dup2", false, 1, NULL); 803 } 804 mutex_enter(&fdp->fd_lock); 805 } 806 dt = fdp->fd_dt; 807 if (dt->dt_ff[newfd] == NULL) { 808 KASSERT(newfd >= NDFDFILE); 809 dt->dt_ff[newfd] = ff; 810 ff = NULL; 811 } 812 fd_used(fdp, newfd); 813 mutex_exit(&fdp->fd_lock); 814 815 fd_set_exclose(curlwp, newfd, (flags & O_CLOEXEC) != 0); 816 fp->f_flag |= flags & (FNONBLOCK|FNOSIGPIPE); 817 /* Slot is now allocated. Insert copy of the file. */ 818 fd_affix(curproc, fp, newfd); 819 if (ff != NULL) { 820 cv_destroy(&ff->ff_closing); 821 kmem_free(ff, sizeof(*ff)); 822 } 823 return 0; 824 } 825 826 /* 827 * Drop reference to a file structure. 828 */ 829 int 830 closef(file_t *fp) 831 { 832 struct flock lf; 833 int error; 834 835 /* 836 * Drop reference. If referenced elsewhere it's still open 837 * and we have nothing more to do. 838 */ 839 mutex_enter(&fp->f_lock); 840 KASSERT(fp->f_count > 0); 841 if (--fp->f_count > 0) { 842 mutex_exit(&fp->f_lock); 843 return 0; 844 } 845 KASSERT(fp->f_count == 0); 846 mutex_exit(&fp->f_lock); 847 848 /* We held the last reference - release locks, close and free. */ 849 if (fp->f_ops->fo_advlock == NULL) { 850 KASSERT((fp->f_flag & FHASLOCK) == 0); 851 } else if (fp->f_flag & FHASLOCK) { 852 lf.l_whence = SEEK_SET; 853 lf.l_start = 0; 854 lf.l_len = 0; 855 lf.l_type = F_UNLCK; 856 (void)(*fp->f_ops->fo_advlock)(fp, fp, F_UNLCK, &lf, F_FLOCK); 857 } 858 if (fp->f_ops != NULL) { 859 error = (*fp->f_ops->fo_close)(fp); 860 } else { 861 error = 0; 862 } 863 KASSERT(fp->f_count == 0); 864 KASSERT(fp->f_cred != NULL); 865 pool_cache_put(file_cache, fp); 866 867 return error; 868 } 869 870 /* 871 * Allocate a file descriptor for the process. 872 * 873 * Future idea for experimentation: replace all of this with radixtree. 874 */ 875 int 876 fd_alloc(proc_t *p, int want, int *result) 877 { 878 filedesc_t *fdp = p->p_fd; 879 int i, lim, last, error, hi; 880 u_int off; 881 fdtab_t *dt; 882 883 KASSERT(p == curproc || p == &proc0); 884 885 /* 886 * Search for a free descriptor starting at the higher 887 * of want or fd_freefile. 888 */ 889 mutex_enter(&fdp->fd_lock); 890 fd_checkmaps(fdp); 891 dt = fdp->fd_dt; 892 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 893 lim = uimin((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles); 894 last = uimin(dt->dt_nfiles, lim); 895 896 for (;;) { 897 if ((i = want) < fdp->fd_freefile) 898 i = fdp->fd_freefile; 899 off = i >> NDENTRYSHIFT; 900 hi = fd_next_zero(fdp, fdp->fd_himap, off, 901 (last + NDENTRIES - 1) >> NDENTRYSHIFT); 902 if (hi == -1) 903 break; 904 i = fd_next_zero(fdp, &fdp->fd_lomap[hi], 905 hi > off ? 0 : i & NDENTRYMASK, NDENTRIES); 906 if (i == -1) { 907 /* 908 * Free file descriptor in this block was 909 * below want, try again with higher want. 910 */ 911 want = (hi + 1) << NDENTRYSHIFT; 912 continue; 913 } 914 i += (hi << NDENTRYSHIFT); 915 if (i >= last) { 916 break; 917 } 918 if (dt->dt_ff[i] == NULL) { 919 KASSERT(i >= NDFDFILE); 920 dt->dt_ff[i] = kmem_alloc(sizeof(fdfile_t), KM_SLEEP); 921 fdfile_ctor(dt->dt_ff[i]); 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 fp->f_cred = kauth_cred_hold(cred); 1141 } 1142 1143 /* 1144 * Don't allow recycled files to be scanned. 1145 * See uipc_usrreq.c. 1146 */ 1147 if (__predict_false((fp->f_flag & FSCAN) != 0)) { 1148 mutex_enter(&fp->f_lock); 1149 atomic_and_uint(&fp->f_flag, ~FSCAN); 1150 mutex_exit(&fp->f_lock); 1151 } 1152 1153 fp->f_advice = 0; 1154 fp->f_offset = 0; 1155 *resultfp = fp; 1156 1157 return 0; 1158 } 1159 1160 /* 1161 * Successful creation of a new descriptor: make visible to the process. 1162 */ 1163 void 1164 fd_affix(proc_t *p, file_t *fp, unsigned fd) 1165 { 1166 fdfile_t *ff; 1167 filedesc_t *fdp; 1168 fdtab_t *dt; 1169 1170 KASSERT(p == curproc || p == &proc0); 1171 1172 /* Add a reference to the file structure. */ 1173 mutex_enter(&fp->f_lock); 1174 fp->f_count++; 1175 mutex_exit(&fp->f_lock); 1176 1177 /* 1178 * Insert the new file into the descriptor slot. 1179 */ 1180 fdp = p->p_fd; 1181 dt = atomic_load_consume(&fdp->fd_dt); 1182 ff = dt->dt_ff[fd]; 1183 1184 KASSERT(ff != NULL); 1185 KASSERT(ff->ff_file == NULL); 1186 KASSERT(ff->ff_allocated); 1187 KASSERT(fd_isused(fdp, fd)); 1188 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1189 1190 /* No need to lock in order to make file initially visible. */ 1191 atomic_store_release(&ff->ff_file, fp); 1192 } 1193 1194 /* 1195 * Abort creation of a new descriptor: free descriptor slot and file. 1196 */ 1197 void 1198 fd_abort(proc_t *p, file_t *fp, unsigned fd) 1199 { 1200 filedesc_t *fdp; 1201 fdfile_t *ff; 1202 1203 KASSERT(p == curproc || p == &proc0); 1204 1205 fdp = p->p_fd; 1206 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd]; 1207 ff->ff_exclose = false; 1208 1209 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1210 1211 mutex_enter(&fdp->fd_lock); 1212 KASSERT(fd_isused(fdp, fd)); 1213 fd_unused(fdp, fd); 1214 mutex_exit(&fdp->fd_lock); 1215 1216 if (fp != NULL) { 1217 KASSERT(fp->f_count == 0); 1218 KASSERT(fp->f_cred != NULL); 1219 pool_cache_put(file_cache, fp); 1220 } 1221 } 1222 1223 static int 1224 file_ctor(void *arg, void *obj, int flags) 1225 { 1226 /* 1227 * It's easy to exhaust the open file limit on a system with many 1228 * CPUs due to caching. Allow a bit of leeway to reduce the element 1229 * of surprise. 1230 */ 1231 u_int slop = PCG_NOBJECTS_NORMAL * (ncpu - 1); 1232 file_t *fp = obj; 1233 1234 memset(fp, 0, sizeof(*fp)); 1235 1236 mutex_enter(&filelist_lock); 1237 if (__predict_false(nfiles >= slop + maxfiles)) { 1238 mutex_exit(&filelist_lock); 1239 tablefull("file", "increase kern.maxfiles or MAXFILES"); 1240 return ENFILE; 1241 } 1242 nfiles++; 1243 LIST_INSERT_HEAD(&filehead, fp, f_list); 1244 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); 1245 fp->f_cred = kauth_cred_hold(curlwp->l_cred); 1246 mutex_exit(&filelist_lock); 1247 1248 return 0; 1249 } 1250 1251 static void 1252 file_dtor(void *arg, void *obj) 1253 { 1254 file_t *fp = obj; 1255 1256 mutex_enter(&filelist_lock); 1257 nfiles--; 1258 LIST_REMOVE(fp, f_list); 1259 mutex_exit(&filelist_lock); 1260 1261 KASSERT(fp->f_count == 0); 1262 kauth_cred_free(fp->f_cred); 1263 mutex_destroy(&fp->f_lock); 1264 } 1265 1266 static void 1267 fdfile_ctor(fdfile_t *ff) 1268 { 1269 1270 memset(ff, 0, sizeof(*ff)); 1271 cv_init(&ff->ff_closing, "fdclose"); 1272 } 1273 1274 static void 1275 fdfile_dtor(fdfile_t *ff) 1276 { 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 fdfile_ctor(*ffp = (fdfile_t *)fdp->fd_dfdfile[i]); 1363 } 1364 1365 return 0; 1366 } 1367 1368 static void 1369 filedesc_dtor(void *arg, void *obj) 1370 { 1371 filedesc_t *fdp = obj; 1372 int i; 1373 1374 for (i = 0; i < NDFDFILE; i++) { 1375 fdfile_dtor((fdfile_t *)fdp->fd_dfdfile[i]); 1376 } 1377 1378 mutex_destroy(&fdp->fd_lock); 1379 } 1380 1381 /* 1382 * Make p share curproc's filedesc structure. 1383 */ 1384 void 1385 fd_share(struct proc *p) 1386 { 1387 filedesc_t *fdp; 1388 1389 fdp = curlwp->l_fd; 1390 p->p_fd = fdp; 1391 atomic_inc_uint(&fdp->fd_refcnt); 1392 } 1393 1394 /* 1395 * Acquire a hold on a filedesc structure. 1396 */ 1397 void 1398 fd_hold(lwp_t *l) 1399 { 1400 filedesc_t *fdp = l->l_fd; 1401 1402 atomic_inc_uint(&fdp->fd_refcnt); 1403 } 1404 1405 /* 1406 * Copy a filedesc structure. 1407 */ 1408 filedesc_t * 1409 fd_copy(void) 1410 { 1411 filedesc_t *newfdp, *fdp; 1412 fdfile_t *ff, **ffp, **nffp, *ff2; 1413 int i, j, numfiles, lastfile, newlast; 1414 file_t *fp; 1415 fdtab_t *newdt; 1416 1417 fdp = curproc->p_fd; 1418 newfdp = pool_cache_get(filedesc_cache, PR_WAITOK); 1419 newfdp->fd_refcnt = 1; 1420 1421 #ifdef DIAGNOSTIC 1422 KASSERT(newfdp->fd_lastfile == -1); 1423 KASSERT(newfdp->fd_lastkqfile == -1); 1424 KASSERT(newfdp->fd_knhash == NULL); 1425 KASSERT(newfdp->fd_freefile == 0); 1426 KASSERT(newfdp->fd_exclose == false); 1427 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin); 1428 KASSERT(newfdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1429 for (i = 0; i < NDFDFILE; i++) { 1430 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == 1431 (fdfile_t *)&newfdp->fd_dfdfile[i]); 1432 } 1433 for (i = NDFDFILE; i < NDFILE; i++) { 1434 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == NULL); 1435 } 1436 #endif /* DIAGNOSTIC */ 1437 1438 mutex_enter(&fdp->fd_lock); 1439 fd_checkmaps(fdp); 1440 numfiles = fdp->fd_dt->dt_nfiles; 1441 lastfile = fdp->fd_lastfile; 1442 1443 /* 1444 * If the number of open files fits in the internal arrays 1445 * of the open file structure, use them, otherwise allocate 1446 * additional memory for the number of descriptors currently 1447 * in use. 1448 */ 1449 if (lastfile < NDFILE) { 1450 i = NDFILE; 1451 newdt = newfdp->fd_dt; 1452 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin); 1453 } else { 1454 /* 1455 * Compute the smallest multiple of NDEXTENT needed 1456 * for the file descriptors currently in use, 1457 * allowing the table to shrink. 1458 */ 1459 i = numfiles; 1460 while (i >= 2 * NDEXTENT && i > lastfile * 2) { 1461 i /= 2; 1462 } 1463 KASSERT(i > NDFILE); 1464 newdt = fd_dtab_alloc(i); 1465 newfdp->fd_dt = newdt; 1466 memcpy(newdt->dt_ff, newfdp->fd_dtbuiltin.dt_ff, 1467 NDFDFILE * sizeof(fdfile_t **)); 1468 memset(newdt->dt_ff + NDFDFILE, 0, 1469 (i - NDFDFILE) * sizeof(fdfile_t **)); 1470 } 1471 if (NDHISLOTS(i) <= NDHISLOTS(NDFILE)) { 1472 newfdp->fd_himap = newfdp->fd_dhimap; 1473 newfdp->fd_lomap = newfdp->fd_dlomap; 1474 } else { 1475 fd_map_alloc(i, &newfdp->fd_lomap, &newfdp->fd_himap); 1476 KASSERT(i >= NDENTRIES * NDENTRIES); 1477 memset(newfdp->fd_himap, 0, NDHISLOTS(i)*sizeof(uint32_t)); 1478 memset(newfdp->fd_lomap, 0, NDLOSLOTS(i)*sizeof(uint32_t)); 1479 } 1480 newfdp->fd_freefile = fdp->fd_freefile; 1481 newfdp->fd_exclose = fdp->fd_exclose; 1482 1483 ffp = fdp->fd_dt->dt_ff; 1484 nffp = newdt->dt_ff; 1485 newlast = -1; 1486 for (i = 0; i <= lastfile; i++, ffp++, nffp++) { 1487 KASSERT(i >= NDFDFILE || 1488 *nffp == (fdfile_t *)newfdp->fd_dfdfile[i]); 1489 ff = *ffp; 1490 if (ff == NULL || 1491 (fp = atomic_load_consume(&ff->ff_file)) == NULL) { 1492 /* Descriptor unused, or descriptor half open. */ 1493 KASSERT(!fd_isused(newfdp, i)); 1494 continue; 1495 } 1496 if (__predict_false(fp->f_type == DTYPE_KQUEUE)) { 1497 /* kqueue descriptors cannot be copied. */ 1498 if (i < newfdp->fd_freefile) { 1499 newfdp->fd_freefile = i; 1500 } 1501 continue; 1502 } 1503 /* It's active: add a reference to the file. */ 1504 mutex_enter(&fp->f_lock); 1505 fp->f_count++; 1506 mutex_exit(&fp->f_lock); 1507 1508 /* Allocate an fdfile_t to represent it. */ 1509 if (i >= NDFDFILE) { 1510 ff2 = kmem_alloc(sizeof(*ff2), KM_SLEEP); 1511 fdfile_ctor(ff2); 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 cv_destroy(&ff->ff_closing); 1601 kmem_free(ff, sizeof(*ff)); 1602 dt->dt_ff[fd] = NULL; 1603 } 1604 } 1605 1606 /* 1607 * Clean out the descriptor table for the next user and return 1608 * to the cache. 1609 */ 1610 if (__predict_false(dt != &fdp->fd_dtbuiltin)) { 1611 fd_dtab_free(fdp->fd_dt); 1612 /* Otherwise, done above. */ 1613 memset(&fdp->fd_dtbuiltin.dt_ff[NDFDFILE], 0, 1614 (NDFILE - NDFDFILE) * sizeof(fdp->fd_dtbuiltin.dt_ff[0])); 1615 fdp->fd_dt = &fdp->fd_dtbuiltin; 1616 } 1617 if (__predict_false(NDHISLOTS(nf) > NDHISLOTS(NDFILE))) { 1618 KASSERT(fdp->fd_himap != fdp->fd_dhimap); 1619 KASSERT(fdp->fd_lomap != fdp->fd_dlomap); 1620 fd_map_free(nf, fdp->fd_lomap, fdp->fd_himap); 1621 } 1622 if (__predict_false(fdp->fd_knhash != NULL)) { 1623 hashdone(fdp->fd_knhash, HASH_LIST, fdp->fd_knhashmask); 1624 fdp->fd_knhash = NULL; 1625 fdp->fd_knhashmask = 0; 1626 } else { 1627 KASSERT(fdp->fd_knhashmask == 0); 1628 } 1629 fdp->fd_dt = &fdp->fd_dtbuiltin; 1630 fdp->fd_lastkqfile = -1; 1631 fdp->fd_lastfile = -1; 1632 fdp->fd_freefile = 0; 1633 fdp->fd_exclose = false; 1634 memset(&fdp->fd_startzero, 0, sizeof(*fdp) - 1635 offsetof(filedesc_t, fd_startzero)); 1636 fdp->fd_himap = fdp->fd_dhimap; 1637 fdp->fd_lomap = fdp->fd_dlomap; 1638 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1639 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL); 1640 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin); 1641 #ifdef DEBUG 1642 fdp->fd_refcnt = 0; /* see fd_checkmaps */ 1643 #endif 1644 fd_checkmaps(fdp); 1645 pool_cache_put(filedesc_cache, fdp); 1646 } 1647 1648 /* 1649 * File Descriptor pseudo-device driver (/dev/fd/). 1650 * 1651 * Opening minor device N dup()s the file (if any) connected to file 1652 * descriptor N belonging to the calling process. Note that this driver 1653 * consists of only the ``open()'' routine, because all subsequent 1654 * references to this file will be direct to the other driver. 1655 */ 1656 static int 1657 filedescopen(dev_t dev, int mode, int type, lwp_t *l) 1658 { 1659 1660 /* 1661 * XXX Kludge: set dupfd to contain the value of the 1662 * the file descriptor being sought for duplication. The error 1663 * return ensures that the vnode for this device will be released 1664 * by vn_open. Open will detect this special error and take the 1665 * actions in fd_dupopen below. Other callers of vn_open or VOP_OPEN 1666 * will simply report the error. 1667 */ 1668 l->l_dupfd = minor(dev); /* XXX */ 1669 return EDUPFD; 1670 } 1671 1672 /* 1673 * Duplicate the specified descriptor to a free descriptor. 1674 * 1675 * old is the original fd. 1676 * moveit is true if we should move rather than duplicate. 1677 * flags are the open flags (converted from O_* to F*). 1678 * newp returns the new fd on success. 1679 * 1680 * These two cases are produced by the EDUPFD and EMOVEFD magic 1681 * errnos, but in the interest of removing that regrettable interface, 1682 * vn_open has been changed to intercept them. Now vn_open returns 1683 * either a vnode or a filehandle, and the filehandle is accompanied 1684 * by a boolean that says whether we should dup (moveit == false) or 1685 * move (moveit == true) the fd. 1686 * 1687 * The dup case is used by /dev/stderr, /proc/self/fd, and such. The 1688 * move case is used by cloner devices that allocate a fd of their 1689 * own (a layering violation that should go away eventually) that 1690 * then needs to be put in the place open() expects it. 1691 */ 1692 int 1693 fd_dupopen(int old, bool moveit, int flags, int *newp) 1694 { 1695 filedesc_t *fdp; 1696 fdfile_t *ff; 1697 file_t *fp; 1698 fdtab_t *dt; 1699 int error; 1700 1701 if ((fp = fd_getfile(old)) == NULL) { 1702 return EBADF; 1703 } 1704 fdp = curlwp->l_fd; 1705 dt = atomic_load_consume(&fdp->fd_dt); 1706 ff = dt->dt_ff[old]; 1707 1708 /* 1709 * There are two cases of interest here. 1710 * 1711 * 1. moveit == false (used to be the EDUPFD magic errno): 1712 * simply dup (old) to file descriptor (new) and return. 1713 * 1714 * 2. moveit == true (used to be the EMOVEFD magic errno): 1715 * steal away the file structure from (old) and store it in 1716 * (new). (old) is effectively closed by this operation. 1717 */ 1718 if (moveit == false) { 1719 /* 1720 * Check that the mode the file is being opened for is a 1721 * subset of the mode of the existing descriptor. 1722 */ 1723 if (((flags & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) { 1724 error = EACCES; 1725 goto out; 1726 } 1727 1728 /* Copy it. */ 1729 error = fd_dup(fp, 0, newp, ff->ff_exclose); 1730 } else { 1731 /* Copy it. */ 1732 error = fd_dup(fp, 0, newp, ff->ff_exclose); 1733 if (error != 0) { 1734 goto out; 1735 } 1736 1737 /* Steal away the file pointer from 'old'. */ 1738 (void)fd_close(old); 1739 return 0; 1740 } 1741 1742 out: 1743 fd_putfile(old); 1744 return error; 1745 } 1746 1747 /* 1748 * Close open files on exec. 1749 */ 1750 void 1751 fd_closeexec(void) 1752 { 1753 proc_t *p; 1754 filedesc_t *fdp; 1755 fdfile_t *ff; 1756 lwp_t *l; 1757 fdtab_t *dt; 1758 int fd; 1759 1760 l = curlwp; 1761 p = l->l_proc; 1762 fdp = p->p_fd; 1763 1764 if (fdp->fd_refcnt > 1) { 1765 fdp = fd_copy(); 1766 fd_free(); 1767 p->p_fd = fdp; 1768 l->l_fd = fdp; 1769 } 1770 if (!fdp->fd_exclose) { 1771 return; 1772 } 1773 fdp->fd_exclose = false; 1774 dt = atomic_load_consume(&fdp->fd_dt); 1775 1776 for (fd = 0; fd <= fdp->fd_lastfile; fd++) { 1777 if ((ff = dt->dt_ff[fd]) == NULL) { 1778 KASSERT(fd >= NDFDFILE); 1779 continue; 1780 } 1781 KASSERT(fd >= NDFDFILE || 1782 ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1783 if (ff->ff_file == NULL) 1784 continue; 1785 if (ff->ff_exclose) { 1786 /* 1787 * We need a reference to close the file. 1788 * No other threads can see the fdfile_t at 1789 * this point, so don't bother locking. 1790 */ 1791 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); 1792 ff->ff_refcnt++; 1793 fd_close(fd); 1794 } 1795 } 1796 } 1797 1798 /* 1799 * Sets descriptor owner. If the owner is a process, 'pgid' 1800 * is set to positive value, process ID. If the owner is process group, 1801 * 'pgid' is set to -pg_id. 1802 */ 1803 int 1804 fsetown(pid_t *pgid, u_long cmd, const void *data) 1805 { 1806 pid_t id = *(const pid_t *)data; 1807 int error; 1808 1809 if (id <= INT_MIN) 1810 return EINVAL; 1811 1812 switch (cmd) { 1813 case TIOCSPGRP: 1814 if (id < 0) 1815 return EINVAL; 1816 id = -id; 1817 break; 1818 default: 1819 break; 1820 } 1821 if (id > 0) { 1822 mutex_enter(&proc_lock); 1823 error = proc_find(id) ? 0 : ESRCH; 1824 mutex_exit(&proc_lock); 1825 } else if (id < 0) { 1826 error = pgid_in_session(curproc, -id); 1827 } else { 1828 error = 0; 1829 } 1830 if (!error) { 1831 *pgid = id; 1832 } 1833 return error; 1834 } 1835 1836 void 1837 fd_set_exclose(struct lwp *l, int fd, bool exclose) 1838 { 1839 filedesc_t *fdp = l->l_fd; 1840 fdfile_t *ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd]; 1841 1842 ff->ff_exclose = exclose; 1843 if (exclose) 1844 fdp->fd_exclose = true; 1845 } 1846 1847 /* 1848 * Return descriptor owner information. If the value is positive, 1849 * it's process ID. If it's negative, it's process group ID and 1850 * needs the sign removed before use. 1851 */ 1852 int 1853 fgetown(pid_t pgid, u_long cmd, void *data) 1854 { 1855 1856 switch (cmd) { 1857 case TIOCGPGRP: 1858 KASSERT(pgid > INT_MIN); 1859 *(int *)data = -pgid; 1860 break; 1861 default: 1862 *(int *)data = pgid; 1863 break; 1864 } 1865 return 0; 1866 } 1867 1868 /* 1869 * Send signal to descriptor owner, either process or process group. 1870 */ 1871 void 1872 fownsignal(pid_t pgid, int signo, int code, int band, void *fdescdata) 1873 { 1874 ksiginfo_t ksi; 1875 1876 KASSERT(!cpu_intr_p()); 1877 1878 if (pgid == 0) { 1879 return; 1880 } 1881 1882 KSI_INIT(&ksi); 1883 ksi.ksi_signo = signo; 1884 ksi.ksi_code = code; 1885 ksi.ksi_band = band; 1886 1887 mutex_enter(&proc_lock); 1888 if (pgid > 0) { 1889 struct proc *p1; 1890 1891 p1 = proc_find(pgid); 1892 if (p1 != NULL) { 1893 kpsignal(p1, &ksi, fdescdata); 1894 } 1895 } else { 1896 struct pgrp *pgrp; 1897 1898 KASSERT(pgid < 0 && pgid > INT_MIN); 1899 pgrp = pgrp_find(-pgid); 1900 if (pgrp != NULL) { 1901 kpgsignal(pgrp, &ksi, fdescdata, 0); 1902 } 1903 } 1904 mutex_exit(&proc_lock); 1905 } 1906 1907 int 1908 fd_clone(file_t *fp, unsigned fd, int flag, const struct fileops *fops, 1909 void *data) 1910 { 1911 1912 fp->f_flag = flag & FMASK; 1913 fd_set_exclose(curlwp, fd, (flag & O_CLOEXEC) != 0); 1914 fp->f_type = DTYPE_MISC; 1915 fp->f_ops = fops; 1916 fp->f_data = data; 1917 curlwp->l_dupfd = fd; 1918 fd_affix(curproc, fp, fd); 1919 1920 return EMOVEFD; 1921 } 1922 1923 int 1924 fnullop_fcntl(file_t *fp, u_int cmd, void *data) 1925 { 1926 1927 if (cmd == F_SETFL) 1928 return 0; 1929 1930 return EOPNOTSUPP; 1931 } 1932 1933 int 1934 fnullop_poll(file_t *fp, int which) 1935 { 1936 1937 return 0; 1938 } 1939 1940 int 1941 fnullop_kqfilter(file_t *fp, struct knote *kn) 1942 { 1943 1944 return EOPNOTSUPP; 1945 } 1946 1947 void 1948 fnullop_restart(file_t *fp) 1949 { 1950 1951 } 1952 1953 int 1954 fbadop_read(file_t *fp, off_t *offset, struct uio *uio, 1955 kauth_cred_t cred, int flags) 1956 { 1957 1958 return EOPNOTSUPP; 1959 } 1960 1961 int 1962 fbadop_write(file_t *fp, off_t *offset, struct uio *uio, 1963 kauth_cred_t cred, int flags) 1964 { 1965 1966 return EOPNOTSUPP; 1967 } 1968 1969 int 1970 fbadop_ioctl(file_t *fp, u_long com, void *data) 1971 { 1972 1973 return EOPNOTSUPP; 1974 } 1975 1976 int 1977 fbadop_stat(file_t *fp, struct stat *sb) 1978 { 1979 1980 return EOPNOTSUPP; 1981 } 1982 1983 int 1984 fbadop_close(file_t *fp) 1985 { 1986 1987 return EOPNOTSUPP; 1988 } 1989 1990 /* 1991 * sysctl routines pertaining to file descriptors 1992 */ 1993 1994 /* Initialized in sysctl_init() for now... */ 1995 extern kmutex_t sysctl_file_marker_lock; 1996 static u_int sysctl_file_marker = 1; 1997 1998 /* 1999 * Expects to be called with proc_lock and sysctl_file_marker_lock locked. 2000 */ 2001 static void 2002 sysctl_file_marker_reset(void) 2003 { 2004 struct proc *p; 2005 2006 PROCLIST_FOREACH(p, &allproc) { 2007 struct filedesc *fd = p->p_fd; 2008 fdtab_t *dt; 2009 u_int i; 2010 2011 mutex_enter(&fd->fd_lock); 2012 dt = fd->fd_dt; 2013 for (i = 0; i < dt->dt_nfiles; i++) { 2014 struct file *fp; 2015 fdfile_t *ff; 2016 2017 if ((ff = dt->dt_ff[i]) == NULL) { 2018 continue; 2019 } 2020 if ((fp = atomic_load_consume(&ff->ff_file)) == NULL) { 2021 continue; 2022 } 2023 fp->f_marker = 0; 2024 } 2025 mutex_exit(&fd->fd_lock); 2026 } 2027 } 2028 2029 /* 2030 * sysctl helper routine for kern.file pseudo-subtree. 2031 */ 2032 static int 2033 sysctl_kern_file(SYSCTLFN_ARGS) 2034 { 2035 const bool allowaddr = get_expose_address(curproc); 2036 struct filelist flist; 2037 int error; 2038 size_t buflen; 2039 struct file *fp, fbuf; 2040 char *start, *where; 2041 struct proc *p; 2042 2043 start = where = oldp; 2044 buflen = *oldlenp; 2045 2046 if (where == NULL) { 2047 /* 2048 * overestimate by 10 files 2049 */ 2050 *oldlenp = sizeof(filehead) + (nfiles + 10) * 2051 sizeof(struct file); 2052 return 0; 2053 } 2054 2055 /* 2056 * first sysctl_copyout filehead 2057 */ 2058 if (buflen < sizeof(filehead)) { 2059 *oldlenp = 0; 2060 return 0; 2061 } 2062 sysctl_unlock(); 2063 if (allowaddr) { 2064 memcpy(&flist, &filehead, sizeof(flist)); 2065 } else { 2066 memset(&flist, 0, sizeof(flist)); 2067 } 2068 error = sysctl_copyout(l, &flist, where, sizeof(flist)); 2069 if (error) { 2070 sysctl_relock(); 2071 return error; 2072 } 2073 buflen -= sizeof(flist); 2074 where += sizeof(flist); 2075 2076 /* 2077 * followed by an array of file structures 2078 */ 2079 mutex_enter(&sysctl_file_marker_lock); 2080 mutex_enter(&proc_lock); 2081 PROCLIST_FOREACH(p, &allproc) { 2082 struct filedesc *fd; 2083 fdtab_t *dt; 2084 u_int i; 2085 2086 if (p->p_stat == SIDL) { 2087 /* skip embryonic processes */ 2088 continue; 2089 } 2090 mutex_enter(p->p_lock); 2091 error = kauth_authorize_process(l->l_cred, 2092 KAUTH_PROCESS_CANSEE, p, 2093 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES), 2094 NULL, NULL); 2095 mutex_exit(p->p_lock); 2096 if (error != 0) { 2097 /* 2098 * Don't leak kauth retval if we're silently 2099 * skipping this entry. 2100 */ 2101 error = 0; 2102 continue; 2103 } 2104 2105 /* 2106 * Grab a hold on the process. 2107 */ 2108 if (!rw_tryenter(&p->p_reflock, RW_READER)) { 2109 continue; 2110 } 2111 mutex_exit(&proc_lock); 2112 2113 fd = p->p_fd; 2114 mutex_enter(&fd->fd_lock); 2115 dt = fd->fd_dt; 2116 for (i = 0; i < dt->dt_nfiles; i++) { 2117 fdfile_t *ff; 2118 2119 if ((ff = dt->dt_ff[i]) == NULL) { 2120 continue; 2121 } 2122 if ((fp = atomic_load_consume(&ff->ff_file)) == NULL) { 2123 continue; 2124 } 2125 2126 mutex_enter(&fp->f_lock); 2127 2128 if ((fp->f_count == 0) || 2129 (fp->f_marker == sysctl_file_marker)) { 2130 mutex_exit(&fp->f_lock); 2131 continue; 2132 } 2133 2134 /* Check that we have enough space. */ 2135 if (buflen < sizeof(struct file)) { 2136 *oldlenp = where - start; 2137 mutex_exit(&fp->f_lock); 2138 error = ENOMEM; 2139 break; 2140 } 2141 2142 fill_file(&fbuf, fp); 2143 mutex_exit(&fp->f_lock); 2144 error = sysctl_copyout(l, &fbuf, where, sizeof(fbuf)); 2145 if (error) { 2146 break; 2147 } 2148 buflen -= sizeof(struct file); 2149 where += sizeof(struct file); 2150 2151 fp->f_marker = sysctl_file_marker; 2152 } 2153 mutex_exit(&fd->fd_lock); 2154 2155 /* 2156 * Release reference to process. 2157 */ 2158 mutex_enter(&proc_lock); 2159 rw_exit(&p->p_reflock); 2160 2161 if (error) 2162 break; 2163 } 2164 2165 sysctl_file_marker++; 2166 /* Reset all markers if wrapped. */ 2167 if (sysctl_file_marker == 0) { 2168 sysctl_file_marker_reset(); 2169 sysctl_file_marker++; 2170 } 2171 2172 mutex_exit(&proc_lock); 2173 mutex_exit(&sysctl_file_marker_lock); 2174 2175 *oldlenp = where - start; 2176 sysctl_relock(); 2177 return error; 2178 } 2179 2180 /* 2181 * sysctl helper function for kern.file2 2182 */ 2183 static int 2184 sysctl_kern_file2(SYSCTLFN_ARGS) 2185 { 2186 struct proc *p; 2187 struct file *fp; 2188 struct filedesc *fd; 2189 struct kinfo_file kf; 2190 char *dp; 2191 u_int i, op; 2192 size_t len, needed, elem_size, out_size; 2193 int error, arg, elem_count; 2194 fdfile_t *ff; 2195 fdtab_t *dt; 2196 2197 if (namelen == 1 && name[0] == CTL_QUERY) 2198 return sysctl_query(SYSCTLFN_CALL(rnode)); 2199 2200 if (namelen != 4) 2201 return EINVAL; 2202 2203 error = 0; 2204 dp = oldp; 2205 len = (oldp != NULL) ? *oldlenp : 0; 2206 op = name[0]; 2207 arg = name[1]; 2208 elem_size = name[2]; 2209 elem_count = name[3]; 2210 out_size = MIN(sizeof(kf), elem_size); 2211 needed = 0; 2212 2213 if (elem_size < 1 || elem_count < 0) 2214 return EINVAL; 2215 2216 switch (op) { 2217 case KERN_FILE_BYFILE: 2218 case KERN_FILE_BYPID: 2219 /* 2220 * We're traversing the process list in both cases; the BYFILE 2221 * case does additional work of keeping track of files already 2222 * looked at. 2223 */ 2224 2225 /* doesn't use arg so it must be zero */ 2226 if ((op == KERN_FILE_BYFILE) && (arg != 0)) 2227 return EINVAL; 2228 2229 if ((op == KERN_FILE_BYPID) && (arg < -1)) 2230 /* -1 means all processes */ 2231 return EINVAL; 2232 2233 sysctl_unlock(); 2234 if (op == KERN_FILE_BYFILE) 2235 mutex_enter(&sysctl_file_marker_lock); 2236 mutex_enter(&proc_lock); 2237 PROCLIST_FOREACH(p, &allproc) { 2238 if (p->p_stat == SIDL) { 2239 /* skip embryonic processes */ 2240 continue; 2241 } 2242 if (arg > 0 && p->p_pid != arg) { 2243 /* pick only the one we want */ 2244 /* XXX want 0 to mean "kernel files" */ 2245 continue; 2246 } 2247 mutex_enter(p->p_lock); 2248 error = kauth_authorize_process(l->l_cred, 2249 KAUTH_PROCESS_CANSEE, p, 2250 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES), 2251 NULL, NULL); 2252 mutex_exit(p->p_lock); 2253 if (error != 0) { 2254 /* 2255 * Don't leak kauth retval if we're silently 2256 * skipping this entry. 2257 */ 2258 error = 0; 2259 continue; 2260 } 2261 2262 /* 2263 * Grab a hold on the process. 2264 */ 2265 if (!rw_tryenter(&p->p_reflock, RW_READER)) { 2266 continue; 2267 } 2268 mutex_exit(&proc_lock); 2269 2270 fd = p->p_fd; 2271 mutex_enter(&fd->fd_lock); 2272 dt = fd->fd_dt; 2273 for (i = 0; i < dt->dt_nfiles; i++) { 2274 if ((ff = dt->dt_ff[i]) == NULL) { 2275 continue; 2276 } 2277 if ((fp = atomic_load_consume(&ff->ff_file)) == 2278 NULL) { 2279 continue; 2280 } 2281 2282 if ((op == KERN_FILE_BYFILE) && 2283 (fp->f_marker == sysctl_file_marker)) { 2284 continue; 2285 } 2286 if (len >= elem_size && elem_count > 0) { 2287 mutex_enter(&fp->f_lock); 2288 fill_file2(&kf, fp, ff, i, p->p_pid); 2289 mutex_exit(&fp->f_lock); 2290 mutex_exit(&fd->fd_lock); 2291 error = sysctl_copyout(l, 2292 &kf, dp, out_size); 2293 mutex_enter(&fd->fd_lock); 2294 if (error) 2295 break; 2296 dp += elem_size; 2297 len -= elem_size; 2298 } 2299 if (op == KERN_FILE_BYFILE) 2300 fp->f_marker = sysctl_file_marker; 2301 needed += elem_size; 2302 if (elem_count > 0 && elem_count != INT_MAX) 2303 elem_count--; 2304 } 2305 mutex_exit(&fd->fd_lock); 2306 2307 /* 2308 * Release reference to process. 2309 */ 2310 mutex_enter(&proc_lock); 2311 rw_exit(&p->p_reflock); 2312 } 2313 if (op == KERN_FILE_BYFILE) { 2314 sysctl_file_marker++; 2315 2316 /* Reset all markers if wrapped. */ 2317 if (sysctl_file_marker == 0) { 2318 sysctl_file_marker_reset(); 2319 sysctl_file_marker++; 2320 } 2321 } 2322 mutex_exit(&proc_lock); 2323 if (op == KERN_FILE_BYFILE) 2324 mutex_exit(&sysctl_file_marker_lock); 2325 sysctl_relock(); 2326 break; 2327 default: 2328 return EINVAL; 2329 } 2330 2331 if (oldp == NULL) 2332 needed += KERN_FILESLOP * elem_size; 2333 *oldlenp = needed; 2334 2335 return error; 2336 } 2337 2338 static void 2339 fill_file(struct file *fp, const struct file *fpsrc) 2340 { 2341 const bool allowaddr = get_expose_address(curproc); 2342 2343 memset(fp, 0, sizeof(*fp)); 2344 2345 fp->f_offset = fpsrc->f_offset; 2346 COND_SET_PTR(fp->f_cred, fpsrc->f_cred, allowaddr); 2347 COND_SET_CPTR(fp->f_ops, fpsrc->f_ops, allowaddr); 2348 COND_SET_STRUCT(fp->f_undata, fpsrc->f_undata, allowaddr); 2349 COND_SET_STRUCT(fp->f_list, fpsrc->f_list, allowaddr); 2350 fp->f_flag = fpsrc->f_flag; 2351 fp->f_marker = fpsrc->f_marker; 2352 fp->f_type = fpsrc->f_type; 2353 fp->f_advice = fpsrc->f_advice; 2354 fp->f_count = fpsrc->f_count; 2355 fp->f_msgcount = fpsrc->f_msgcount; 2356 fp->f_unpcount = fpsrc->f_unpcount; 2357 COND_SET_STRUCT(fp->f_unplist, fpsrc->f_unplist, allowaddr); 2358 } 2359 2360 static void 2361 fill_file2(struct kinfo_file *kp, const file_t *fp, const fdfile_t *ff, 2362 int i, pid_t pid) 2363 { 2364 const bool allowaddr = get_expose_address(curproc); 2365 2366 memset(kp, 0, sizeof(*kp)); 2367 2368 COND_SET_VALUE(kp->ki_fileaddr, PTRTOUINT64(fp), allowaddr); 2369 kp->ki_flag = fp->f_flag; 2370 kp->ki_iflags = 0; 2371 kp->ki_ftype = fp->f_type; 2372 kp->ki_count = fp->f_count; 2373 kp->ki_msgcount = fp->f_msgcount; 2374 COND_SET_VALUE(kp->ki_fucred, PTRTOUINT64(fp->f_cred), allowaddr); 2375 kp->ki_fuid = kauth_cred_geteuid(fp->f_cred); 2376 kp->ki_fgid = kauth_cred_getegid(fp->f_cred); 2377 COND_SET_VALUE(kp->ki_fops, PTRTOUINT64(fp->f_ops), allowaddr); 2378 kp->ki_foffset = fp->f_offset; 2379 COND_SET_VALUE(kp->ki_fdata, PTRTOUINT64(fp->f_data), allowaddr); 2380 2381 /* vnode information to glue this file to something */ 2382 if (fp->f_type == DTYPE_VNODE) { 2383 struct vnode *vp = fp->f_vnode; 2384 2385 COND_SET_VALUE(kp->ki_vun, PTRTOUINT64(vp->v_un.vu_socket), 2386 allowaddr); 2387 kp->ki_vsize = vp->v_size; 2388 kp->ki_vtype = vp->v_type; 2389 kp->ki_vtag = vp->v_tag; 2390 COND_SET_VALUE(kp->ki_vdata, PTRTOUINT64(vp->v_data), 2391 allowaddr); 2392 } 2393 2394 /* process information when retrieved via KERN_FILE_BYPID */ 2395 if (ff != NULL) { 2396 kp->ki_pid = pid; 2397 kp->ki_fd = i; 2398 kp->ki_ofileflags = ff->ff_exclose; 2399 kp->ki_usecount = ff->ff_refcnt; 2400 } 2401 } 2402