1 /* $NetBSD: kern_descrip.c,v 1.235 2018/07/03 23:14:57 kamil 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 1.235 2018/07/03 23:14:57 kamil 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 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 file_cache = pool_cache_init(sizeof(file_t), coherency_unit, 0, 154 0, "file", NULL, IPL_NONE, file_ctor, file_dtor, NULL); 155 KASSERT(file_cache != NULL); 156 157 fdfile_cache = pool_cache_init(sizeof(fdfile_t), coherency_unit, 0, 158 PR_LARGECACHE, "fdfile", NULL, IPL_NONE, fdfile_ctor, fdfile_dtor, 159 NULL); 160 KASSERT(fdfile_cache != NULL); 161 162 filedesc_cache = pool_cache_init(sizeof(filedesc_t), coherency_unit, 163 0, 0, "filedesc", NULL, IPL_NONE, filedesc_ctor, filedesc_dtor, 164 NULL); 165 KASSERT(filedesc_cache != NULL); 166 167 sysctl_createv(&clog, 0, NULL, NULL, 168 CTLFLAG_PERMANENT, 169 CTLTYPE_STRUCT, "file", 170 SYSCTL_DESCR("System open file table"), 171 sysctl_kern_file, 0, NULL, 0, 172 CTL_KERN, KERN_FILE, CTL_EOL); 173 sysctl_createv(&clog, 0, NULL, NULL, 174 CTLFLAG_PERMANENT, 175 CTLTYPE_STRUCT, "file2", 176 SYSCTL_DESCR("System open file table"), 177 sysctl_kern_file2, 0, NULL, 0, 178 CTL_KERN, KERN_FILE2, CTL_EOL); 179 } 180 181 static bool 182 fd_isused(filedesc_t *fdp, unsigned fd) 183 { 184 u_int off = fd >> NDENTRYSHIFT; 185 186 KASSERT(fd < fdp->fd_dt->dt_nfiles); 187 188 return (fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) != 0; 189 } 190 191 /* 192 * Verify that the bitmaps match the descriptor table. 193 */ 194 static inline void 195 fd_checkmaps(filedesc_t *fdp) 196 { 197 #ifdef DEBUG 198 fdtab_t *dt; 199 u_int fd; 200 201 dt = fdp->fd_dt; 202 if (fdp->fd_refcnt == -1) { 203 /* 204 * fd_free tears down the table without maintaining its bitmap. 205 */ 206 return; 207 } 208 for (fd = 0; fd < dt->dt_nfiles; fd++) { 209 if (fd < NDFDFILE) { 210 KASSERT(dt->dt_ff[fd] == 211 (fdfile_t *)fdp->fd_dfdfile[fd]); 212 } 213 if (dt->dt_ff[fd] == NULL) { 214 KASSERT(!fd_isused(fdp, fd)); 215 } else if (dt->dt_ff[fd]->ff_file != NULL) { 216 KASSERT(fd_isused(fdp, fd)); 217 } 218 } 219 #endif 220 } 221 222 static int 223 fd_next_zero(filedesc_t *fdp, uint32_t *bitmap, int want, u_int bits) 224 { 225 int i, off, maxoff; 226 uint32_t sub; 227 228 KASSERT(mutex_owned(&fdp->fd_lock)); 229 230 fd_checkmaps(fdp); 231 232 if (want > bits) 233 return -1; 234 235 off = want >> NDENTRYSHIFT; 236 i = want & NDENTRYMASK; 237 if (i) { 238 sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i)); 239 if (sub != ~0) 240 goto found; 241 off++; 242 } 243 244 maxoff = NDLOSLOTS(bits); 245 while (off < maxoff) { 246 if ((sub = bitmap[off]) != ~0) 247 goto found; 248 off++; 249 } 250 251 return -1; 252 253 found: 254 return (off << NDENTRYSHIFT) + ffs(~sub) - 1; 255 } 256 257 static int 258 fd_last_set(filedesc_t *fd, int last) 259 { 260 int off, i; 261 fdfile_t **ff = fd->fd_dt->dt_ff; 262 uint32_t *bitmap = fd->fd_lomap; 263 264 KASSERT(mutex_owned(&fd->fd_lock)); 265 266 fd_checkmaps(fd); 267 268 off = (last - 1) >> NDENTRYSHIFT; 269 270 while (off >= 0 && !bitmap[off]) 271 off--; 272 273 if (off < 0) 274 return -1; 275 276 i = ((off + 1) << NDENTRYSHIFT) - 1; 277 if (i >= last) 278 i = last - 1; 279 280 /* XXX should use bitmap */ 281 while (i > 0 && (ff[i] == NULL || !ff[i]->ff_allocated)) 282 i--; 283 284 return i; 285 } 286 287 static inline void 288 fd_used(filedesc_t *fdp, unsigned fd) 289 { 290 u_int off = fd >> NDENTRYSHIFT; 291 fdfile_t *ff; 292 293 ff = fdp->fd_dt->dt_ff[fd]; 294 295 KASSERT(mutex_owned(&fdp->fd_lock)); 296 KASSERT((fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) == 0); 297 KASSERT(ff != NULL); 298 KASSERT(ff->ff_file == NULL); 299 KASSERT(!ff->ff_allocated); 300 301 ff->ff_allocated = true; 302 fdp->fd_lomap[off] |= 1U << (fd & NDENTRYMASK); 303 if (__predict_false(fdp->fd_lomap[off] == ~0)) { 304 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & 305 (1U << (off & NDENTRYMASK))) == 0); 306 fdp->fd_himap[off >> NDENTRYSHIFT] |= 1U << (off & NDENTRYMASK); 307 } 308 309 if ((int)fd > fdp->fd_lastfile) { 310 fdp->fd_lastfile = fd; 311 } 312 313 fd_checkmaps(fdp); 314 } 315 316 static inline void 317 fd_unused(filedesc_t *fdp, unsigned fd) 318 { 319 u_int off = fd >> NDENTRYSHIFT; 320 fdfile_t *ff; 321 322 ff = fdp->fd_dt->dt_ff[fd]; 323 324 /* 325 * Don't assert the lock is held here, as we may be copying 326 * the table during exec() and it is not needed there. 327 * procfs and sysctl are locked out by proc::p_reflock. 328 * 329 * KASSERT(mutex_owned(&fdp->fd_lock)); 330 */ 331 KASSERT(ff != NULL); 332 KASSERT(ff->ff_file == NULL); 333 KASSERT(ff->ff_allocated); 334 335 if (fd < fdp->fd_freefile) { 336 fdp->fd_freefile = fd; 337 } 338 339 if (fdp->fd_lomap[off] == ~0) { 340 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & 341 (1U << (off & NDENTRYMASK))) != 0); 342 fdp->fd_himap[off >> NDENTRYSHIFT] &= 343 ~(1U << (off & NDENTRYMASK)); 344 } 345 KASSERT((fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) != 0); 346 fdp->fd_lomap[off] &= ~(1U << (fd & NDENTRYMASK)); 347 ff->ff_allocated = false; 348 349 KASSERT(fd <= fdp->fd_lastfile); 350 if (fd == fdp->fd_lastfile) { 351 fdp->fd_lastfile = fd_last_set(fdp, fd); 352 } 353 fd_checkmaps(fdp); 354 } 355 356 /* 357 * Look up the file structure corresponding to a file descriptor 358 * and return the file, holding a reference on the descriptor. 359 */ 360 file_t * 361 fd_getfile(unsigned fd) 362 { 363 filedesc_t *fdp; 364 fdfile_t *ff; 365 file_t *fp; 366 fdtab_t *dt; 367 368 /* 369 * Look up the fdfile structure representing this descriptor. 370 * We are doing this unlocked. See fd_tryexpand(). 371 */ 372 fdp = curlwp->l_fd; 373 dt = fdp->fd_dt; 374 if (__predict_false(fd >= dt->dt_nfiles)) { 375 return NULL; 376 } 377 ff = dt->dt_ff[fd]; 378 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 379 if (__predict_false(ff == NULL)) { 380 return NULL; 381 } 382 383 /* Now get a reference to the descriptor. */ 384 if (fdp->fd_refcnt == 1) { 385 /* 386 * Single threaded: don't need to worry about concurrent 387 * access (other than earlier calls to kqueue, which may 388 * hold a reference to the descriptor). 389 */ 390 ff->ff_refcnt++; 391 } else { 392 /* 393 * Multi threaded: issue a memory barrier to ensure that we 394 * acquire the file pointer _after_ adding a reference. If 395 * no memory barrier, we could fetch a stale pointer. 396 */ 397 atomic_inc_uint(&ff->ff_refcnt); 398 #ifndef __HAVE_ATOMIC_AS_MEMBAR 399 membar_enter(); 400 #endif 401 } 402 403 /* 404 * If the file is not open or is being closed then put the 405 * reference back. 406 */ 407 fp = ff->ff_file; 408 if (__predict_true(fp != NULL)) { 409 return fp; 410 } 411 fd_putfile(fd); 412 return NULL; 413 } 414 415 /* 416 * Release a reference to a file descriptor acquired with fd_getfile(). 417 */ 418 void 419 fd_putfile(unsigned fd) 420 { 421 filedesc_t *fdp; 422 fdfile_t *ff; 423 u_int u, v; 424 425 fdp = curlwp->l_fd; 426 ff = fdp->fd_dt->dt_ff[fd]; 427 428 KASSERT(fd < fdp->fd_dt->dt_nfiles); 429 KASSERT(ff != NULL); 430 KASSERT((ff->ff_refcnt & FR_MASK) > 0); 431 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 432 433 if (fdp->fd_refcnt == 1) { 434 /* 435 * Single threaded: don't need to worry about concurrent 436 * access (other than earlier calls to kqueue, which may 437 * hold a reference to the descriptor). 438 */ 439 if (__predict_false((ff->ff_refcnt & FR_CLOSING) != 0)) { 440 fd_close(fd); 441 return; 442 } 443 ff->ff_refcnt--; 444 return; 445 } 446 447 /* 448 * Ensure that any use of the file is complete and globally 449 * visible before dropping the final reference. If no membar, 450 * the current CPU could still access memory associated with 451 * the file after it has been freed or recycled by another 452 * CPU. 453 */ 454 #ifndef __HAVE_ATOMIC_AS_MEMBAR 455 membar_exit(); 456 #endif 457 458 /* 459 * Be optimistic and start out with the assumption that no other 460 * threads are trying to close the descriptor. If the CAS fails, 461 * we lost a race and/or it's being closed. 462 */ 463 for (u = ff->ff_refcnt & FR_MASK;; u = v) { 464 v = atomic_cas_uint(&ff->ff_refcnt, u, u - 1); 465 if (__predict_true(u == v)) { 466 return; 467 } 468 if (__predict_false((v & FR_CLOSING) != 0)) { 469 break; 470 } 471 } 472 473 /* Another thread is waiting to close the file: join it. */ 474 (void)fd_close(fd); 475 } 476 477 /* 478 * Convenience wrapper around fd_getfile() that returns reference 479 * to a vnode. 480 */ 481 int 482 fd_getvnode(unsigned fd, file_t **fpp) 483 { 484 vnode_t *vp; 485 file_t *fp; 486 487 fp = fd_getfile(fd); 488 if (__predict_false(fp == NULL)) { 489 return EBADF; 490 } 491 if (__predict_false(fp->f_type != DTYPE_VNODE)) { 492 fd_putfile(fd); 493 return EINVAL; 494 } 495 vp = fp->f_vnode; 496 if (__predict_false(vp->v_type == VBAD)) { 497 /* XXX Is this case really necessary? */ 498 fd_putfile(fd); 499 return EBADF; 500 } 501 *fpp = fp; 502 return 0; 503 } 504 505 /* 506 * Convenience wrapper around fd_getfile() that returns reference 507 * to a socket. 508 */ 509 int 510 fd_getsock1(unsigned fd, struct socket **sop, file_t **fp) 511 { 512 *fp = fd_getfile(fd); 513 if (__predict_false(*fp == NULL)) { 514 return EBADF; 515 } 516 if (__predict_false((*fp)->f_type != DTYPE_SOCKET)) { 517 fd_putfile(fd); 518 return ENOTSOCK; 519 } 520 *sop = (*fp)->f_socket; 521 return 0; 522 } 523 524 int 525 fd_getsock(unsigned fd, struct socket **sop) 526 { 527 file_t *fp; 528 return fd_getsock1(fd, sop, &fp); 529 } 530 531 /* 532 * Look up the file structure corresponding to a file descriptor 533 * and return it with a reference held on the file, not the 534 * descriptor. 535 * 536 * This is heavyweight and only used when accessing descriptors 537 * from a foreign process. The caller must ensure that `p' does 538 * not exit or fork across this call. 539 * 540 * To release the file (not descriptor) reference, use closef(). 541 */ 542 file_t * 543 fd_getfile2(proc_t *p, unsigned fd) 544 { 545 filedesc_t *fdp; 546 fdfile_t *ff; 547 file_t *fp; 548 fdtab_t *dt; 549 550 fdp = p->p_fd; 551 mutex_enter(&fdp->fd_lock); 552 dt = fdp->fd_dt; 553 if (fd >= dt->dt_nfiles) { 554 mutex_exit(&fdp->fd_lock); 555 return NULL; 556 } 557 if ((ff = dt->dt_ff[fd]) == NULL) { 558 mutex_exit(&fdp->fd_lock); 559 return NULL; 560 } 561 if ((fp = ff->ff_file) == NULL) { 562 mutex_exit(&fdp->fd_lock); 563 return NULL; 564 } 565 mutex_enter(&fp->f_lock); 566 fp->f_count++; 567 mutex_exit(&fp->f_lock); 568 mutex_exit(&fdp->fd_lock); 569 570 return fp; 571 } 572 573 /* 574 * Internal form of close. Must be called with a reference to the 575 * descriptor, and will drop the reference. When all descriptor 576 * references are dropped, releases the descriptor slot and a single 577 * reference to the file structure. 578 */ 579 int 580 fd_close(unsigned fd) 581 { 582 struct flock lf; 583 filedesc_t *fdp; 584 fdfile_t *ff; 585 file_t *fp; 586 proc_t *p; 587 lwp_t *l; 588 u_int refcnt; 589 590 l = curlwp; 591 p = l->l_proc; 592 fdp = l->l_fd; 593 ff = fdp->fd_dt->dt_ff[fd]; 594 595 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 596 597 mutex_enter(&fdp->fd_lock); 598 KASSERT((ff->ff_refcnt & FR_MASK) > 0); 599 if (__predict_false(ff->ff_file == NULL)) { 600 /* 601 * Another user of the file is already closing, and is 602 * waiting for other users of the file to drain. Release 603 * our reference, and wake up the closer. 604 */ 605 atomic_dec_uint(&ff->ff_refcnt); 606 cv_broadcast(&ff->ff_closing); 607 mutex_exit(&fdp->fd_lock); 608 609 /* 610 * An application error, so pretend that the descriptor 611 * was already closed. We can't safely wait for it to 612 * be closed without potentially deadlocking. 613 */ 614 return (EBADF); 615 } 616 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); 617 618 /* 619 * There may be multiple users of this file within the process. 620 * Notify existing and new users that the file is closing. This 621 * will prevent them from adding additional uses to this file 622 * while we are closing it. 623 */ 624 fp = ff->ff_file; 625 ff->ff_file = NULL; 626 ff->ff_exclose = false; 627 628 /* 629 * We expect the caller to hold a descriptor reference - drop it. 630 * The reference count may increase beyond zero at this point due 631 * to an erroneous descriptor reference by an application, but 632 * fd_getfile() will notice that the file is being closed and drop 633 * the reference again. 634 */ 635 if (fdp->fd_refcnt == 1) { 636 /* Single threaded. */ 637 refcnt = --(ff->ff_refcnt); 638 } else { 639 /* Multi threaded. */ 640 #ifndef __HAVE_ATOMIC_AS_MEMBAR 641 membar_producer(); 642 #endif 643 refcnt = atomic_dec_uint_nv(&ff->ff_refcnt); 644 } 645 if (__predict_false(refcnt != 0)) { 646 /* 647 * Wait for other references to drain. This is typically 648 * an application error - the descriptor is being closed 649 * while still in use. 650 * (Or just a threaded application trying to unblock its 651 * thread that sleeps in (say) accept()). 652 */ 653 atomic_or_uint(&ff->ff_refcnt, FR_CLOSING); 654 655 /* 656 * Remove any knotes attached to the file. A knote 657 * attached to the descriptor can hold references on it. 658 */ 659 mutex_exit(&fdp->fd_lock); 660 if (!SLIST_EMPTY(&ff->ff_knlist)) { 661 knote_fdclose(fd); 662 } 663 664 /* 665 * Since the file system code doesn't know which fd 666 * each request came from (think dup()), we have to 667 * ask it to return ERESTART for any long-term blocks. 668 * The re-entry through read/write/etc will detect the 669 * closed fd and return EBAFD. 670 * Blocked partial writes may return a short length. 671 */ 672 (*fp->f_ops->fo_restart)(fp); 673 mutex_enter(&fdp->fd_lock); 674 675 /* 676 * We need to see the count drop to zero at least once, 677 * in order to ensure that all pre-existing references 678 * have been drained. New references past this point are 679 * of no interest. 680 * XXX (dsl) this may need to call fo_restart() after a 681 * timeout to guarantee that all the system calls exit. 682 */ 683 while ((ff->ff_refcnt & FR_MASK) != 0) { 684 cv_wait(&ff->ff_closing, &fdp->fd_lock); 685 } 686 atomic_and_uint(&ff->ff_refcnt, ~FR_CLOSING); 687 } else { 688 /* If no references, there must be no knotes. */ 689 KASSERT(SLIST_EMPTY(&ff->ff_knlist)); 690 } 691 692 /* 693 * POSIX record locking dictates that any close releases ALL 694 * locks owned by this process. This is handled by setting 695 * a flag in the unlock to free ONLY locks obeying POSIX 696 * semantics, and not to free BSD-style file locks. 697 * If the descriptor was in a message, POSIX-style locks 698 * aren't passed with the descriptor. 699 */ 700 if (__predict_false((p->p_flag & PK_ADVLOCK) != 0 && 701 fp->f_type == DTYPE_VNODE)) { 702 lf.l_whence = SEEK_SET; 703 lf.l_start = 0; 704 lf.l_len = 0; 705 lf.l_type = F_UNLCK; 706 mutex_exit(&fdp->fd_lock); 707 (void)VOP_ADVLOCK(fp->f_vnode, p, F_UNLCK, &lf, F_POSIX); 708 mutex_enter(&fdp->fd_lock); 709 } 710 711 /* Free descriptor slot. */ 712 fd_unused(fdp, fd); 713 mutex_exit(&fdp->fd_lock); 714 715 /* Now drop reference to the file itself. */ 716 return closef(fp); 717 } 718 719 /* 720 * Duplicate a file descriptor. 721 */ 722 int 723 fd_dup(file_t *fp, int minfd, int *newp, bool exclose) 724 { 725 proc_t *p = curproc; 726 int error; 727 728 while ((error = fd_alloc(p, minfd, newp)) != 0) { 729 if (error != ENOSPC) { 730 return error; 731 } 732 fd_tryexpand(p); 733 } 734 735 curlwp->l_fd->fd_dt->dt_ff[*newp]->ff_exclose = exclose; 736 fd_affix(p, fp, *newp); 737 return 0; 738 } 739 740 /* 741 * dup2 operation. 742 */ 743 int 744 fd_dup2(file_t *fp, unsigned newfd, int flags) 745 { 746 filedesc_t *fdp = curlwp->l_fd; 747 fdfile_t *ff; 748 fdtab_t *dt; 749 750 if (flags & ~(O_CLOEXEC|O_NONBLOCK)) 751 return EINVAL; 752 /* 753 * Ensure there are enough slots in the descriptor table, 754 * and allocate an fdfile_t up front in case we need it. 755 */ 756 while (newfd >= fdp->fd_dt->dt_nfiles) { 757 fd_tryexpand(curproc); 758 } 759 ff = pool_cache_get(fdfile_cache, PR_WAITOK); 760 761 /* 762 * If there is already a file open, close it. If the file is 763 * half open, wait for it to be constructed before closing it. 764 * XXX Potential for deadlock here? 765 */ 766 mutex_enter(&fdp->fd_lock); 767 while (fd_isused(fdp, newfd)) { 768 mutex_exit(&fdp->fd_lock); 769 if (fd_getfile(newfd) != NULL) { 770 (void)fd_close(newfd); 771 } else { 772 /* 773 * Crummy, but unlikely to happen. 774 * Can occur if we interrupt another 775 * thread while it is opening a file. 776 */ 777 kpause("dup2", false, 1, NULL); 778 } 779 mutex_enter(&fdp->fd_lock); 780 } 781 dt = fdp->fd_dt; 782 if (dt->dt_ff[newfd] == NULL) { 783 KASSERT(newfd >= NDFDFILE); 784 dt->dt_ff[newfd] = ff; 785 ff = NULL; 786 } 787 fd_used(fdp, newfd); 788 mutex_exit(&fdp->fd_lock); 789 790 dt->dt_ff[newfd]->ff_exclose = (flags & O_CLOEXEC) != 0; 791 fp->f_flag |= flags & FNONBLOCK; 792 /* Slot is now allocated. Insert copy of the file. */ 793 fd_affix(curproc, fp, newfd); 794 if (ff != NULL) { 795 pool_cache_put(fdfile_cache, ff); 796 } 797 return 0; 798 } 799 800 /* 801 * Drop reference to a file structure. 802 */ 803 int 804 closef(file_t *fp) 805 { 806 struct flock lf; 807 int error; 808 809 /* 810 * Drop reference. If referenced elsewhere it's still open 811 * and we have nothing more to do. 812 */ 813 mutex_enter(&fp->f_lock); 814 KASSERT(fp->f_count > 0); 815 if (--fp->f_count > 0) { 816 mutex_exit(&fp->f_lock); 817 return 0; 818 } 819 KASSERT(fp->f_count == 0); 820 mutex_exit(&fp->f_lock); 821 822 /* We held the last reference - release locks, close and free. */ 823 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) { 824 lf.l_whence = SEEK_SET; 825 lf.l_start = 0; 826 lf.l_len = 0; 827 lf.l_type = F_UNLCK; 828 (void)VOP_ADVLOCK(fp->f_vnode, fp, F_UNLCK, &lf, F_FLOCK); 829 } 830 if (fp->f_ops != NULL) { 831 error = (*fp->f_ops->fo_close)(fp); 832 } else { 833 error = 0; 834 } 835 KASSERT(fp->f_count == 0); 836 KASSERT(fp->f_cred != NULL); 837 pool_cache_put(file_cache, fp); 838 839 return error; 840 } 841 842 /* 843 * Allocate a file descriptor for the process. 844 */ 845 int 846 fd_alloc(proc_t *p, int want, int *result) 847 { 848 filedesc_t *fdp = p->p_fd; 849 int i, lim, last, error, hi; 850 u_int off; 851 fdtab_t *dt; 852 853 KASSERT(p == curproc || p == &proc0); 854 855 /* 856 * Search for a free descriptor starting at the higher 857 * of want or fd_freefile. 858 */ 859 mutex_enter(&fdp->fd_lock); 860 fd_checkmaps(fdp); 861 dt = fdp->fd_dt; 862 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 863 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles); 864 last = min(dt->dt_nfiles, lim); 865 for (;;) { 866 if ((i = want) < fdp->fd_freefile) 867 i = fdp->fd_freefile; 868 off = i >> NDENTRYSHIFT; 869 hi = fd_next_zero(fdp, fdp->fd_himap, off, 870 (last + NDENTRIES - 1) >> NDENTRYSHIFT); 871 if (hi == -1) 872 break; 873 i = fd_next_zero(fdp, &fdp->fd_lomap[hi], 874 hi > off ? 0 : i & NDENTRYMASK, NDENTRIES); 875 if (i == -1) { 876 /* 877 * Free file descriptor in this block was 878 * below want, try again with higher want. 879 */ 880 want = (hi + 1) << NDENTRYSHIFT; 881 continue; 882 } 883 i += (hi << NDENTRYSHIFT); 884 if (i >= last) { 885 break; 886 } 887 if (dt->dt_ff[i] == NULL) { 888 KASSERT(i >= NDFDFILE); 889 dt->dt_ff[i] = pool_cache_get(fdfile_cache, PR_WAITOK); 890 } 891 KASSERT(dt->dt_ff[i]->ff_file == NULL); 892 fd_used(fdp, i); 893 if (want <= fdp->fd_freefile) { 894 fdp->fd_freefile = i; 895 } 896 *result = i; 897 KASSERT(i >= NDFDFILE || 898 dt->dt_ff[i] == (fdfile_t *)fdp->fd_dfdfile[i]); 899 fd_checkmaps(fdp); 900 mutex_exit(&fdp->fd_lock); 901 return 0; 902 } 903 904 /* No space in current array. Let the caller expand and retry. */ 905 error = (dt->dt_nfiles >= lim) ? EMFILE : ENOSPC; 906 mutex_exit(&fdp->fd_lock); 907 return error; 908 } 909 910 /* 911 * Allocate memory for a descriptor table. 912 */ 913 static fdtab_t * 914 fd_dtab_alloc(int n) 915 { 916 fdtab_t *dt; 917 size_t sz; 918 919 KASSERT(n > NDFILE); 920 921 sz = sizeof(*dt) + (n - NDFILE) * sizeof(dt->dt_ff[0]); 922 dt = kmem_alloc(sz, KM_SLEEP); 923 #ifdef DIAGNOSTIC 924 memset(dt, 0xff, sz); 925 #endif 926 dt->dt_nfiles = n; 927 dt->dt_link = NULL; 928 return dt; 929 } 930 931 /* 932 * Free a descriptor table, and all tables linked for deferred free. 933 */ 934 static void 935 fd_dtab_free(fdtab_t *dt) 936 { 937 fdtab_t *next; 938 size_t sz; 939 940 do { 941 next = dt->dt_link; 942 KASSERT(dt->dt_nfiles > NDFILE); 943 sz = sizeof(*dt) + 944 (dt->dt_nfiles - NDFILE) * sizeof(dt->dt_ff[0]); 945 #ifdef DIAGNOSTIC 946 memset(dt, 0xff, sz); 947 #endif 948 kmem_free(dt, sz); 949 dt = next; 950 } while (dt != NULL); 951 } 952 953 /* 954 * Allocate descriptor bitmap. 955 */ 956 static void 957 fd_map_alloc(int n, uint32_t **lo, uint32_t **hi) 958 { 959 uint8_t *ptr; 960 size_t szlo, szhi; 961 962 KASSERT(n > NDENTRIES); 963 964 szlo = NDLOSLOTS(n) * sizeof(uint32_t); 965 szhi = NDHISLOTS(n) * sizeof(uint32_t); 966 ptr = kmem_alloc(szlo + szhi, KM_SLEEP); 967 *lo = (uint32_t *)ptr; 968 *hi = (uint32_t *)(ptr + szlo); 969 } 970 971 /* 972 * Free descriptor bitmap. 973 */ 974 static void 975 fd_map_free(int n, uint32_t *lo, uint32_t *hi) 976 { 977 size_t szlo, szhi; 978 979 KASSERT(n > NDENTRIES); 980 981 szlo = NDLOSLOTS(n) * sizeof(uint32_t); 982 szhi = NDHISLOTS(n) * sizeof(uint32_t); 983 KASSERT(hi == (uint32_t *)((uint8_t *)lo + szlo)); 984 kmem_free(lo, szlo + szhi); 985 } 986 987 /* 988 * Expand a process' descriptor table. 989 */ 990 void 991 fd_tryexpand(proc_t *p) 992 { 993 filedesc_t *fdp; 994 int i, numfiles, oldnfiles; 995 fdtab_t *newdt, *dt; 996 uint32_t *newhimap, *newlomap; 997 998 KASSERT(p == curproc || p == &proc0); 999 1000 fdp = p->p_fd; 1001 newhimap = NULL; 1002 newlomap = NULL; 1003 oldnfiles = fdp->fd_dt->dt_nfiles; 1004 1005 if (oldnfiles < NDEXTENT) 1006 numfiles = NDEXTENT; 1007 else 1008 numfiles = 2 * oldnfiles; 1009 1010 newdt = fd_dtab_alloc(numfiles); 1011 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1012 fd_map_alloc(numfiles, &newlomap, &newhimap); 1013 } 1014 1015 mutex_enter(&fdp->fd_lock); 1016 dt = fdp->fd_dt; 1017 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1018 if (dt->dt_nfiles != oldnfiles) { 1019 /* fdp changed; caller must retry */ 1020 mutex_exit(&fdp->fd_lock); 1021 fd_dtab_free(newdt); 1022 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1023 fd_map_free(numfiles, newlomap, newhimap); 1024 } 1025 return; 1026 } 1027 1028 /* Copy the existing descriptor table and zero the new portion. */ 1029 i = sizeof(fdfile_t *) * oldnfiles; 1030 memcpy(newdt->dt_ff, dt->dt_ff, i); 1031 memset((uint8_t *)newdt->dt_ff + i, 0, 1032 numfiles * sizeof(fdfile_t *) - i); 1033 1034 /* 1035 * Link old descriptor array into list to be discarded. We defer 1036 * freeing until the last reference to the descriptor table goes 1037 * away (usually process exit). This allows us to do lockless 1038 * lookups in fd_getfile(). 1039 */ 1040 if (oldnfiles > NDFILE) { 1041 if (fdp->fd_refcnt > 1) { 1042 newdt->dt_link = dt; 1043 } else { 1044 fd_dtab_free(dt); 1045 } 1046 } 1047 1048 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1049 i = NDHISLOTS(oldnfiles) * sizeof(uint32_t); 1050 memcpy(newhimap, fdp->fd_himap, i); 1051 memset((uint8_t *)newhimap + i, 0, 1052 NDHISLOTS(numfiles) * sizeof(uint32_t) - i); 1053 1054 i = NDLOSLOTS(oldnfiles) * sizeof(uint32_t); 1055 memcpy(newlomap, fdp->fd_lomap, i); 1056 memset((uint8_t *)newlomap + i, 0, 1057 NDLOSLOTS(numfiles) * sizeof(uint32_t) - i); 1058 1059 if (NDHISLOTS(oldnfiles) > NDHISLOTS(NDFILE)) { 1060 fd_map_free(oldnfiles, fdp->fd_lomap, fdp->fd_himap); 1061 } 1062 fdp->fd_himap = newhimap; 1063 fdp->fd_lomap = newlomap; 1064 } 1065 1066 /* 1067 * All other modifications must become globally visible before 1068 * the change to fd_dt. See fd_getfile(). 1069 */ 1070 membar_producer(); 1071 fdp->fd_dt = newdt; 1072 KASSERT(newdt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1073 fd_checkmaps(fdp); 1074 mutex_exit(&fdp->fd_lock); 1075 } 1076 1077 /* 1078 * Create a new open file structure and allocate a file descriptor 1079 * for the current process. 1080 */ 1081 int 1082 fd_allocfile(file_t **resultfp, int *resultfd) 1083 { 1084 proc_t *p = curproc; 1085 kauth_cred_t cred; 1086 file_t *fp; 1087 int error; 1088 1089 while ((error = fd_alloc(p, 0, resultfd)) != 0) { 1090 if (error != ENOSPC) { 1091 return error; 1092 } 1093 fd_tryexpand(p); 1094 } 1095 1096 fp = pool_cache_get(file_cache, PR_WAITOK); 1097 if (fp == NULL) { 1098 fd_abort(p, NULL, *resultfd); 1099 return ENFILE; 1100 } 1101 KASSERT(fp->f_count == 0); 1102 KASSERT(fp->f_msgcount == 0); 1103 KASSERT(fp->f_unpcount == 0); 1104 1105 /* Replace cached credentials if not what we need. */ 1106 cred = curlwp->l_cred; 1107 if (__predict_false(cred != fp->f_cred)) { 1108 kauth_cred_free(fp->f_cred); 1109 kauth_cred_hold(cred); 1110 fp->f_cred = cred; 1111 } 1112 1113 /* 1114 * Don't allow recycled files to be scanned. 1115 * See uipc_usrreq.c. 1116 */ 1117 if (__predict_false((fp->f_flag & FSCAN) != 0)) { 1118 mutex_enter(&fp->f_lock); 1119 atomic_and_uint(&fp->f_flag, ~FSCAN); 1120 mutex_exit(&fp->f_lock); 1121 } 1122 1123 fp->f_advice = 0; 1124 fp->f_offset = 0; 1125 *resultfp = fp; 1126 1127 return 0; 1128 } 1129 1130 /* 1131 * Successful creation of a new descriptor: make visible to the process. 1132 */ 1133 void 1134 fd_affix(proc_t *p, file_t *fp, unsigned fd) 1135 { 1136 fdfile_t *ff; 1137 filedesc_t *fdp; 1138 1139 KASSERT(p == curproc || p == &proc0); 1140 1141 /* Add a reference to the file structure. */ 1142 mutex_enter(&fp->f_lock); 1143 fp->f_count++; 1144 mutex_exit(&fp->f_lock); 1145 1146 /* 1147 * Insert the new file into the descriptor slot. 1148 * 1149 * The memory barriers provided by lock activity in this routine 1150 * ensure that any updates to the file structure become globally 1151 * visible before the file becomes visible to other LWPs in the 1152 * current process. 1153 */ 1154 fdp = p->p_fd; 1155 ff = fdp->fd_dt->dt_ff[fd]; 1156 1157 KASSERT(ff != NULL); 1158 KASSERT(ff->ff_file == NULL); 1159 KASSERT(ff->ff_allocated); 1160 KASSERT(fd_isused(fdp, fd)); 1161 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1162 1163 /* No need to lock in order to make file initially visible. */ 1164 ff->ff_file = fp; 1165 } 1166 1167 /* 1168 * Abort creation of a new descriptor: free descriptor slot and file. 1169 */ 1170 void 1171 fd_abort(proc_t *p, file_t *fp, unsigned fd) 1172 { 1173 filedesc_t *fdp; 1174 fdfile_t *ff; 1175 1176 KASSERT(p == curproc || p == &proc0); 1177 1178 fdp = p->p_fd; 1179 ff = fdp->fd_dt->dt_ff[fd]; 1180 ff->ff_exclose = false; 1181 1182 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1183 1184 mutex_enter(&fdp->fd_lock); 1185 KASSERT(fd_isused(fdp, fd)); 1186 fd_unused(fdp, fd); 1187 mutex_exit(&fdp->fd_lock); 1188 1189 if (fp != NULL) { 1190 KASSERT(fp->f_count == 0); 1191 KASSERT(fp->f_cred != NULL); 1192 pool_cache_put(file_cache, fp); 1193 } 1194 } 1195 1196 static int 1197 file_ctor(void *arg, void *obj, int flags) 1198 { 1199 file_t *fp = obj; 1200 1201 memset(fp, 0, sizeof(*fp)); 1202 1203 mutex_enter(&filelist_lock); 1204 if (__predict_false(nfiles >= maxfiles)) { 1205 mutex_exit(&filelist_lock); 1206 tablefull("file", "increase kern.maxfiles or MAXFILES"); 1207 return ENFILE; 1208 } 1209 nfiles++; 1210 LIST_INSERT_HEAD(&filehead, fp, f_list); 1211 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); 1212 fp->f_cred = curlwp->l_cred; 1213 kauth_cred_hold(fp->f_cred); 1214 mutex_exit(&filelist_lock); 1215 1216 return 0; 1217 } 1218 1219 static void 1220 file_dtor(void *arg, void *obj) 1221 { 1222 file_t *fp = obj; 1223 1224 mutex_enter(&filelist_lock); 1225 nfiles--; 1226 LIST_REMOVE(fp, f_list); 1227 mutex_exit(&filelist_lock); 1228 1229 kauth_cred_free(fp->f_cred); 1230 mutex_destroy(&fp->f_lock); 1231 } 1232 1233 static int 1234 fdfile_ctor(void *arg, void *obj, int flags) 1235 { 1236 fdfile_t *ff = obj; 1237 1238 memset(ff, 0, sizeof(*ff)); 1239 cv_init(&ff->ff_closing, "fdclose"); 1240 1241 return 0; 1242 } 1243 1244 static void 1245 fdfile_dtor(void *arg, void *obj) 1246 { 1247 fdfile_t *ff = obj; 1248 1249 cv_destroy(&ff->ff_closing); 1250 } 1251 1252 file_t * 1253 fgetdummy(void) 1254 { 1255 file_t *fp; 1256 1257 fp = kmem_zalloc(sizeof(*fp), KM_SLEEP); 1258 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); 1259 return fp; 1260 } 1261 1262 void 1263 fputdummy(file_t *fp) 1264 { 1265 1266 mutex_destroy(&fp->f_lock); 1267 kmem_free(fp, sizeof(*fp)); 1268 } 1269 1270 /* 1271 * Create an initial filedesc structure. 1272 */ 1273 filedesc_t * 1274 fd_init(filedesc_t *fdp) 1275 { 1276 #ifdef DIAGNOSTIC 1277 unsigned fd; 1278 #endif 1279 1280 if (__predict_true(fdp == NULL)) { 1281 fdp = pool_cache_get(filedesc_cache, PR_WAITOK); 1282 } else { 1283 KASSERT(fdp == &filedesc0); 1284 filedesc_ctor(NULL, fdp, PR_WAITOK); 1285 } 1286 1287 #ifdef DIAGNOSTIC 1288 KASSERT(fdp->fd_lastfile == -1); 1289 KASSERT(fdp->fd_lastkqfile == -1); 1290 KASSERT(fdp->fd_knhash == NULL); 1291 KASSERT(fdp->fd_freefile == 0); 1292 KASSERT(fdp->fd_exclose == false); 1293 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin); 1294 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1295 for (fd = 0; fd < NDFDFILE; fd++) { 1296 KASSERT(fdp->fd_dtbuiltin.dt_ff[fd] == 1297 (fdfile_t *)fdp->fd_dfdfile[fd]); 1298 } 1299 for (fd = NDFDFILE; fd < NDFILE; fd++) { 1300 KASSERT(fdp->fd_dtbuiltin.dt_ff[fd] == NULL); 1301 } 1302 KASSERT(fdp->fd_himap == fdp->fd_dhimap); 1303 KASSERT(fdp->fd_lomap == fdp->fd_dlomap); 1304 #endif /* DIAGNOSTIC */ 1305 1306 fdp->fd_refcnt = 1; 1307 fd_checkmaps(fdp); 1308 1309 return fdp; 1310 } 1311 1312 /* 1313 * Initialize a file descriptor table. 1314 */ 1315 static int 1316 filedesc_ctor(void *arg, void *obj, int flag) 1317 { 1318 filedesc_t *fdp = obj; 1319 fdfile_t **ffp; 1320 int i; 1321 1322 memset(fdp, 0, sizeof(*fdp)); 1323 mutex_init(&fdp->fd_lock, MUTEX_DEFAULT, IPL_NONE); 1324 fdp->fd_lastfile = -1; 1325 fdp->fd_lastkqfile = -1; 1326 fdp->fd_dt = &fdp->fd_dtbuiltin; 1327 fdp->fd_dtbuiltin.dt_nfiles = NDFILE; 1328 fdp->fd_himap = fdp->fd_dhimap; 1329 fdp->fd_lomap = fdp->fd_dlomap; 1330 1331 CTASSERT(sizeof(fdp->fd_dfdfile[0]) >= sizeof(fdfile_t)); 1332 for (i = 0, ffp = fdp->fd_dt->dt_ff; i < NDFDFILE; i++, ffp++) { 1333 *ffp = (fdfile_t *)fdp->fd_dfdfile[i]; 1334 (void)fdfile_ctor(NULL, fdp->fd_dfdfile[i], PR_WAITOK); 1335 } 1336 1337 return 0; 1338 } 1339 1340 static void 1341 filedesc_dtor(void *arg, void *obj) 1342 { 1343 filedesc_t *fdp = obj; 1344 int i; 1345 1346 for (i = 0; i < NDFDFILE; i++) { 1347 fdfile_dtor(NULL, fdp->fd_dfdfile[i]); 1348 } 1349 1350 mutex_destroy(&fdp->fd_lock); 1351 } 1352 1353 /* 1354 * Make p share curproc's filedesc structure. 1355 */ 1356 void 1357 fd_share(struct proc *p) 1358 { 1359 filedesc_t *fdp; 1360 1361 fdp = curlwp->l_fd; 1362 p->p_fd = fdp; 1363 atomic_inc_uint(&fdp->fd_refcnt); 1364 } 1365 1366 /* 1367 * Acquire a hold on a filedesc structure. 1368 */ 1369 void 1370 fd_hold(lwp_t *l) 1371 { 1372 filedesc_t *fdp = l->l_fd; 1373 1374 atomic_inc_uint(&fdp->fd_refcnt); 1375 } 1376 1377 /* 1378 * Copy a filedesc structure. 1379 */ 1380 filedesc_t * 1381 fd_copy(void) 1382 { 1383 filedesc_t *newfdp, *fdp; 1384 fdfile_t *ff, **ffp, **nffp, *ff2; 1385 int i, j, numfiles, lastfile, newlast; 1386 file_t *fp; 1387 fdtab_t *newdt; 1388 1389 fdp = curproc->p_fd; 1390 newfdp = pool_cache_get(filedesc_cache, PR_WAITOK); 1391 newfdp->fd_refcnt = 1; 1392 1393 #ifdef DIAGNOSTIC 1394 KASSERT(newfdp->fd_lastfile == -1); 1395 KASSERT(newfdp->fd_lastkqfile == -1); 1396 KASSERT(newfdp->fd_knhash == NULL); 1397 KASSERT(newfdp->fd_freefile == 0); 1398 KASSERT(newfdp->fd_exclose == false); 1399 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin); 1400 KASSERT(newfdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1401 for (i = 0; i < NDFDFILE; i++) { 1402 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == 1403 (fdfile_t *)&newfdp->fd_dfdfile[i]); 1404 } 1405 for (i = NDFDFILE; i < NDFILE; i++) { 1406 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == NULL); 1407 } 1408 #endif /* DIAGNOSTIC */ 1409 1410 mutex_enter(&fdp->fd_lock); 1411 fd_checkmaps(fdp); 1412 numfiles = fdp->fd_dt->dt_nfiles; 1413 lastfile = fdp->fd_lastfile; 1414 1415 /* 1416 * If the number of open files fits in the internal arrays 1417 * of the open file structure, use them, otherwise allocate 1418 * additional memory for the number of descriptors currently 1419 * in use. 1420 */ 1421 if (lastfile < NDFILE) { 1422 i = NDFILE; 1423 newdt = newfdp->fd_dt; 1424 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin); 1425 } else { 1426 /* 1427 * Compute the smallest multiple of NDEXTENT needed 1428 * for the file descriptors currently in use, 1429 * allowing the table to shrink. 1430 */ 1431 i = numfiles; 1432 while (i >= 2 * NDEXTENT && i > lastfile * 2) { 1433 i /= 2; 1434 } 1435 KASSERT(i > NDFILE); 1436 newdt = fd_dtab_alloc(i); 1437 newfdp->fd_dt = newdt; 1438 memcpy(newdt->dt_ff, newfdp->fd_dtbuiltin.dt_ff, 1439 NDFDFILE * sizeof(fdfile_t **)); 1440 memset(newdt->dt_ff + NDFDFILE, 0, 1441 (i - NDFDFILE) * sizeof(fdfile_t **)); 1442 } 1443 if (NDHISLOTS(i) <= NDHISLOTS(NDFILE)) { 1444 newfdp->fd_himap = newfdp->fd_dhimap; 1445 newfdp->fd_lomap = newfdp->fd_dlomap; 1446 } else { 1447 fd_map_alloc(i, &newfdp->fd_lomap, &newfdp->fd_himap); 1448 KASSERT(i >= NDENTRIES * NDENTRIES); 1449 memset(newfdp->fd_himap, 0, NDHISLOTS(i)*sizeof(uint32_t)); 1450 memset(newfdp->fd_lomap, 0, NDLOSLOTS(i)*sizeof(uint32_t)); 1451 } 1452 newfdp->fd_freefile = fdp->fd_freefile; 1453 newfdp->fd_exclose = fdp->fd_exclose; 1454 1455 ffp = fdp->fd_dt->dt_ff; 1456 nffp = newdt->dt_ff; 1457 newlast = -1; 1458 for (i = 0; i <= lastfile; i++, ffp++, nffp++) { 1459 KASSERT(i >= NDFDFILE || 1460 *nffp == (fdfile_t *)newfdp->fd_dfdfile[i]); 1461 ff = *ffp; 1462 if (ff == NULL || (fp = ff->ff_file) == NULL) { 1463 /* Descriptor unused, or descriptor half open. */ 1464 KASSERT(!fd_isused(newfdp, i)); 1465 continue; 1466 } 1467 if (__predict_false(fp->f_type == DTYPE_KQUEUE)) { 1468 /* kqueue descriptors cannot be copied. */ 1469 if (i < newfdp->fd_freefile) { 1470 newfdp->fd_freefile = i; 1471 } 1472 continue; 1473 } 1474 /* It's active: add a reference to the file. */ 1475 mutex_enter(&fp->f_lock); 1476 fp->f_count++; 1477 mutex_exit(&fp->f_lock); 1478 1479 /* Allocate an fdfile_t to represent it. */ 1480 if (i >= NDFDFILE) { 1481 ff2 = pool_cache_get(fdfile_cache, PR_WAITOK); 1482 *nffp = ff2; 1483 } else { 1484 ff2 = newdt->dt_ff[i]; 1485 } 1486 ff2->ff_file = fp; 1487 ff2->ff_exclose = ff->ff_exclose; 1488 ff2->ff_allocated = true; 1489 1490 /* Fix up bitmaps. */ 1491 j = i >> NDENTRYSHIFT; 1492 KASSERT((newfdp->fd_lomap[j] & (1U << (i & NDENTRYMASK))) == 0); 1493 newfdp->fd_lomap[j] |= 1U << (i & NDENTRYMASK); 1494 if (__predict_false(newfdp->fd_lomap[j] == ~0)) { 1495 KASSERT((newfdp->fd_himap[j >> NDENTRYSHIFT] & 1496 (1U << (j & NDENTRYMASK))) == 0); 1497 newfdp->fd_himap[j >> NDENTRYSHIFT] |= 1498 1U << (j & NDENTRYMASK); 1499 } 1500 newlast = i; 1501 } 1502 KASSERT(newdt->dt_ff[0] == (fdfile_t *)newfdp->fd_dfdfile[0]); 1503 newfdp->fd_lastfile = newlast; 1504 fd_checkmaps(newfdp); 1505 mutex_exit(&fdp->fd_lock); 1506 1507 return newfdp; 1508 } 1509 1510 /* 1511 * Release a filedesc structure. 1512 */ 1513 void 1514 fd_free(void) 1515 { 1516 fdfile_t *ff; 1517 file_t *fp; 1518 int fd, nf; 1519 fdtab_t *dt; 1520 lwp_t * const l = curlwp; 1521 filedesc_t * const fdp = l->l_fd; 1522 const bool noadvlock = (l->l_proc->p_flag & PK_ADVLOCK) == 0; 1523 1524 KASSERT(fdp->fd_dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1525 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1526 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL); 1527 1528 #ifndef __HAVE_ATOMIC_AS_MEMBAR 1529 membar_exit(); 1530 #endif 1531 if (atomic_dec_uint_nv(&fdp->fd_refcnt) > 0) 1532 return; 1533 1534 /* 1535 * Close any files that the process holds open. 1536 */ 1537 dt = fdp->fd_dt; 1538 fd_checkmaps(fdp); 1539 #ifdef DEBUG 1540 fdp->fd_refcnt = -1; /* see fd_checkmaps */ 1541 #endif 1542 for (fd = 0, nf = dt->dt_nfiles; fd < nf; fd++) { 1543 ff = dt->dt_ff[fd]; 1544 KASSERT(fd >= NDFDFILE || 1545 ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1546 if (ff == NULL) 1547 continue; 1548 if ((fp = ff->ff_file) != NULL) { 1549 /* 1550 * Must use fd_close() here if there is 1551 * a reference from kqueue or we might have posix 1552 * advisory locks. 1553 */ 1554 if (__predict_true(ff->ff_refcnt == 0) && 1555 (noadvlock || fp->f_type != DTYPE_VNODE)) { 1556 ff->ff_file = NULL; 1557 ff->ff_exclose = false; 1558 ff->ff_allocated = false; 1559 closef(fp); 1560 } else { 1561 ff->ff_refcnt++; 1562 fd_close(fd); 1563 } 1564 } 1565 KASSERT(ff->ff_refcnt == 0); 1566 KASSERT(ff->ff_file == NULL); 1567 KASSERT(!ff->ff_exclose); 1568 KASSERT(!ff->ff_allocated); 1569 if (fd >= NDFDFILE) { 1570 pool_cache_put(fdfile_cache, ff); 1571 dt->dt_ff[fd] = NULL; 1572 } 1573 } 1574 1575 /* 1576 * Clean out the descriptor table for the next user and return 1577 * to the cache. 1578 */ 1579 if (__predict_false(dt != &fdp->fd_dtbuiltin)) { 1580 fd_dtab_free(fdp->fd_dt); 1581 /* Otherwise, done above. */ 1582 memset(&fdp->fd_dtbuiltin.dt_ff[NDFDFILE], 0, 1583 (NDFILE - NDFDFILE) * sizeof(fdp->fd_dtbuiltin.dt_ff[0])); 1584 fdp->fd_dt = &fdp->fd_dtbuiltin; 1585 } 1586 if (__predict_false(NDHISLOTS(nf) > NDHISLOTS(NDFILE))) { 1587 KASSERT(fdp->fd_himap != fdp->fd_dhimap); 1588 KASSERT(fdp->fd_lomap != fdp->fd_dlomap); 1589 fd_map_free(nf, fdp->fd_lomap, fdp->fd_himap); 1590 } 1591 if (__predict_false(fdp->fd_knhash != NULL)) { 1592 hashdone(fdp->fd_knhash, HASH_LIST, fdp->fd_knhashmask); 1593 fdp->fd_knhash = NULL; 1594 fdp->fd_knhashmask = 0; 1595 } else { 1596 KASSERT(fdp->fd_knhashmask == 0); 1597 } 1598 fdp->fd_dt = &fdp->fd_dtbuiltin; 1599 fdp->fd_lastkqfile = -1; 1600 fdp->fd_lastfile = -1; 1601 fdp->fd_freefile = 0; 1602 fdp->fd_exclose = false; 1603 memset(&fdp->fd_startzero, 0, sizeof(*fdp) - 1604 offsetof(filedesc_t, fd_startzero)); 1605 fdp->fd_himap = fdp->fd_dhimap; 1606 fdp->fd_lomap = fdp->fd_dlomap; 1607 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1608 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL); 1609 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin); 1610 #ifdef DEBUG 1611 fdp->fd_refcnt = 0; /* see fd_checkmaps */ 1612 #endif 1613 fd_checkmaps(fdp); 1614 pool_cache_put(filedesc_cache, fdp); 1615 } 1616 1617 /* 1618 * File Descriptor pseudo-device driver (/dev/fd/). 1619 * 1620 * Opening minor device N dup()s the file (if any) connected to file 1621 * descriptor N belonging to the calling process. Note that this driver 1622 * consists of only the ``open()'' routine, because all subsequent 1623 * references to this file will be direct to the other driver. 1624 */ 1625 static int 1626 filedescopen(dev_t dev, int mode, int type, lwp_t *l) 1627 { 1628 1629 /* 1630 * XXX Kludge: set dupfd to contain the value of the 1631 * the file descriptor being sought for duplication. The error 1632 * return ensures that the vnode for this device will be released 1633 * by vn_open. Open will detect this special error and take the 1634 * actions in fd_dupopen below. Other callers of vn_open or VOP_OPEN 1635 * will simply report the error. 1636 */ 1637 l->l_dupfd = minor(dev); /* XXX */ 1638 return EDUPFD; 1639 } 1640 1641 /* 1642 * Duplicate the specified descriptor to a free descriptor. 1643 */ 1644 int 1645 fd_dupopen(int old, int *newp, int mode, int error) 1646 { 1647 filedesc_t *fdp; 1648 fdfile_t *ff; 1649 file_t *fp; 1650 fdtab_t *dt; 1651 1652 if ((fp = fd_getfile(old)) == NULL) { 1653 return EBADF; 1654 } 1655 fdp = curlwp->l_fd; 1656 dt = fdp->fd_dt; 1657 ff = dt->dt_ff[old]; 1658 1659 /* 1660 * There are two cases of interest here. 1661 * 1662 * For EDUPFD simply dup (old) to file descriptor 1663 * (new) and return. 1664 * 1665 * For EMOVEFD steal away the file structure from (old) and 1666 * store it in (new). (old) is effectively closed by 1667 * this operation. 1668 * 1669 * Any other error code is just returned. 1670 */ 1671 switch (error) { 1672 case EDUPFD: 1673 /* 1674 * Check that the mode the file is being opened for is a 1675 * subset of the mode of the existing descriptor. 1676 */ 1677 if (((mode & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) { 1678 error = EACCES; 1679 break; 1680 } 1681 1682 /* Copy it. */ 1683 error = fd_dup(fp, 0, newp, ff->ff_exclose); 1684 break; 1685 1686 case EMOVEFD: 1687 /* Copy it. */ 1688 error = fd_dup(fp, 0, newp, ff->ff_exclose); 1689 if (error != 0) { 1690 break; 1691 } 1692 1693 /* Steal away the file pointer from 'old'. */ 1694 (void)fd_close(old); 1695 return 0; 1696 } 1697 1698 fd_putfile(old); 1699 return error; 1700 } 1701 1702 /* 1703 * Close open files on exec. 1704 */ 1705 void 1706 fd_closeexec(void) 1707 { 1708 proc_t *p; 1709 filedesc_t *fdp; 1710 fdfile_t *ff; 1711 lwp_t *l; 1712 fdtab_t *dt; 1713 int fd; 1714 1715 l = curlwp; 1716 p = l->l_proc; 1717 fdp = p->p_fd; 1718 1719 if (fdp->fd_refcnt > 1) { 1720 fdp = fd_copy(); 1721 fd_free(); 1722 p->p_fd = fdp; 1723 l->l_fd = fdp; 1724 } 1725 if (!fdp->fd_exclose) { 1726 return; 1727 } 1728 fdp->fd_exclose = false; 1729 dt = fdp->fd_dt; 1730 1731 for (fd = 0; fd <= fdp->fd_lastfile; fd++) { 1732 if ((ff = dt->dt_ff[fd]) == NULL) { 1733 KASSERT(fd >= NDFDFILE); 1734 continue; 1735 } 1736 KASSERT(fd >= NDFDFILE || 1737 ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1738 if (ff->ff_file == NULL) 1739 continue; 1740 if (ff->ff_exclose) { 1741 /* 1742 * We need a reference to close the file. 1743 * No other threads can see the fdfile_t at 1744 * this point, so don't bother locking. 1745 */ 1746 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); 1747 ff->ff_refcnt++; 1748 fd_close(fd); 1749 } 1750 } 1751 } 1752 1753 /* 1754 * Sets descriptor owner. If the owner is a process, 'pgid' 1755 * is set to positive value, process ID. If the owner is process group, 1756 * 'pgid' is set to -pg_id. 1757 */ 1758 int 1759 fsetown(pid_t *pgid, u_long cmd, const void *data) 1760 { 1761 pid_t id = *(const pid_t *)data; 1762 int error; 1763 1764 switch (cmd) { 1765 case TIOCSPGRP: 1766 if (id < 0) 1767 return EINVAL; 1768 id = -id; 1769 break; 1770 default: 1771 break; 1772 } 1773 if (id > 0) { 1774 mutex_enter(proc_lock); 1775 error = proc_find(id) ? 0 : ESRCH; 1776 mutex_exit(proc_lock); 1777 } else if (id < 0) { 1778 error = pgid_in_session(curproc, -id); 1779 } else { 1780 error = 0; 1781 } 1782 if (!error) { 1783 *pgid = id; 1784 } 1785 return error; 1786 } 1787 1788 void 1789 fd_set_exclose(struct lwp *l, int fd, bool exclose) 1790 { 1791 filedesc_t *fdp = l->l_fd; 1792 fdfile_t *ff = fdp->fd_dt->dt_ff[fd]; 1793 1794 ff->ff_exclose = exclose; 1795 if (exclose) 1796 fdp->fd_exclose = true; 1797 } 1798 1799 /* 1800 * Return descriptor owner information. If the value is positive, 1801 * it's process ID. If it's negative, it's process group ID and 1802 * needs the sign removed before use. 1803 */ 1804 int 1805 fgetown(pid_t pgid, u_long cmd, void *data) 1806 { 1807 1808 switch (cmd) { 1809 case TIOCGPGRP: 1810 *(int *)data = -pgid; 1811 break; 1812 default: 1813 *(int *)data = pgid; 1814 break; 1815 } 1816 return 0; 1817 } 1818 1819 /* 1820 * Send signal to descriptor owner, either process or process group. 1821 */ 1822 void 1823 fownsignal(pid_t pgid, int signo, int code, int band, void *fdescdata) 1824 { 1825 ksiginfo_t ksi; 1826 1827 KASSERT(!cpu_intr_p()); 1828 1829 if (pgid == 0) { 1830 return; 1831 } 1832 1833 KSI_INIT(&ksi); 1834 ksi.ksi_signo = signo; 1835 ksi.ksi_code = code; 1836 ksi.ksi_band = band; 1837 1838 mutex_enter(proc_lock); 1839 if (pgid > 0) { 1840 struct proc *p1; 1841 1842 p1 = proc_find(pgid); 1843 if (p1 != NULL) { 1844 kpsignal(p1, &ksi, fdescdata); 1845 } 1846 } else { 1847 struct pgrp *pgrp; 1848 1849 KASSERT(pgid < 0); 1850 pgrp = pgrp_find(-pgid); 1851 if (pgrp != NULL) { 1852 kpgsignal(pgrp, &ksi, fdescdata, 0); 1853 } 1854 } 1855 mutex_exit(proc_lock); 1856 } 1857 1858 int 1859 fd_clone(file_t *fp, unsigned fd, int flag, const struct fileops *fops, 1860 void *data) 1861 { 1862 fdfile_t *ff; 1863 filedesc_t *fdp; 1864 1865 fp->f_flag = flag & FMASK; 1866 fdp = curproc->p_fd; 1867 ff = fdp->fd_dt->dt_ff[fd]; 1868 KASSERT(ff != NULL); 1869 ff->ff_exclose = (flag & O_CLOEXEC) != 0; 1870 fp->f_type = DTYPE_MISC; 1871 fp->f_ops = fops; 1872 fp->f_data = data; 1873 curlwp->l_dupfd = fd; 1874 fd_affix(curproc, fp, fd); 1875 1876 return EMOVEFD; 1877 } 1878 1879 int 1880 fnullop_fcntl(file_t *fp, u_int cmd, void *data) 1881 { 1882 1883 if (cmd == F_SETFL) 1884 return 0; 1885 1886 return EOPNOTSUPP; 1887 } 1888 1889 int 1890 fnullop_poll(file_t *fp, int which) 1891 { 1892 1893 return 0; 1894 } 1895 1896 int 1897 fnullop_kqfilter(file_t *fp, struct knote *kn) 1898 { 1899 1900 return EOPNOTSUPP; 1901 } 1902 1903 void 1904 fnullop_restart(file_t *fp) 1905 { 1906 1907 } 1908 1909 int 1910 fbadop_read(file_t *fp, off_t *offset, struct uio *uio, 1911 kauth_cred_t cred, int flags) 1912 { 1913 1914 return EOPNOTSUPP; 1915 } 1916 1917 int 1918 fbadop_write(file_t *fp, off_t *offset, struct uio *uio, 1919 kauth_cred_t cred, int flags) 1920 { 1921 1922 return EOPNOTSUPP; 1923 } 1924 1925 int 1926 fbadop_ioctl(file_t *fp, u_long com, void *data) 1927 { 1928 1929 return EOPNOTSUPP; 1930 } 1931 1932 int 1933 fbadop_stat(file_t *fp, struct stat *sb) 1934 { 1935 1936 return EOPNOTSUPP; 1937 } 1938 1939 int 1940 fbadop_close(file_t *fp) 1941 { 1942 1943 return EOPNOTSUPP; 1944 } 1945 1946 /* 1947 * sysctl routines pertaining to file descriptors 1948 */ 1949 1950 /* Initialized in sysctl_init() for now... */ 1951 extern kmutex_t sysctl_file_marker_lock; 1952 static u_int sysctl_file_marker = 1; 1953 1954 /* 1955 * Expects to be called with proc_lock and sysctl_file_marker_lock locked. 1956 */ 1957 static void 1958 sysctl_file_marker_reset(void) 1959 { 1960 struct proc *p; 1961 1962 PROCLIST_FOREACH(p, &allproc) { 1963 struct filedesc *fd = p->p_fd; 1964 fdtab_t *dt; 1965 u_int i; 1966 1967 mutex_enter(&fd->fd_lock); 1968 dt = fd->fd_dt; 1969 for (i = 0; i < dt->dt_nfiles; i++) { 1970 struct file *fp; 1971 fdfile_t *ff; 1972 1973 if ((ff = dt->dt_ff[i]) == NULL) { 1974 continue; 1975 } 1976 if ((fp = ff->ff_file) == NULL) { 1977 continue; 1978 } 1979 fp->f_marker = 0; 1980 } 1981 mutex_exit(&fd->fd_lock); 1982 } 1983 } 1984 1985 /* 1986 * sysctl helper routine for kern.file pseudo-subtree. 1987 */ 1988 static int 1989 sysctl_kern_file(SYSCTLFN_ARGS) 1990 { 1991 int error; 1992 size_t buflen; 1993 struct file *fp, fbuf; 1994 char *start, *where; 1995 struct proc *p; 1996 1997 start = where = oldp; 1998 buflen = *oldlenp; 1999 2000 if (where == NULL) { 2001 /* 2002 * overestimate by 10 files 2003 */ 2004 *oldlenp = sizeof(filehead) + (nfiles + 10) * 2005 sizeof(struct file); 2006 return 0; 2007 } 2008 2009 /* 2010 * first sysctl_copyout filehead 2011 */ 2012 if (buflen < sizeof(filehead)) { 2013 *oldlenp = 0; 2014 return 0; 2015 } 2016 sysctl_unlock(); 2017 error = sysctl_copyout(l, &filehead, where, sizeof(filehead)); 2018 if (error) { 2019 sysctl_relock(); 2020 return error; 2021 } 2022 buflen -= sizeof(filehead); 2023 where += sizeof(filehead); 2024 2025 /* 2026 * followed by an array of file structures 2027 */ 2028 mutex_enter(&sysctl_file_marker_lock); 2029 mutex_enter(proc_lock); 2030 PROCLIST_FOREACH(p, &allproc) { 2031 struct filedesc *fd; 2032 fdtab_t *dt; 2033 u_int i; 2034 2035 if (p->p_stat == SIDL) { 2036 /* skip embryonic processes */ 2037 continue; 2038 } 2039 mutex_enter(p->p_lock); 2040 error = kauth_authorize_process(l->l_cred, 2041 KAUTH_PROCESS_CANSEE, p, 2042 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES), 2043 NULL, NULL); 2044 mutex_exit(p->p_lock); 2045 if (error != 0) { 2046 /* 2047 * Don't leak kauth retval if we're silently 2048 * skipping this entry. 2049 */ 2050 error = 0; 2051 continue; 2052 } 2053 2054 /* 2055 * Grab a hold on the process. 2056 */ 2057 if (!rw_tryenter(&p->p_reflock, RW_READER)) { 2058 continue; 2059 } 2060 mutex_exit(proc_lock); 2061 2062 fd = p->p_fd; 2063 mutex_enter(&fd->fd_lock); 2064 dt = fd->fd_dt; 2065 for (i = 0; i < dt->dt_nfiles; i++) { 2066 fdfile_t *ff; 2067 2068 if ((ff = dt->dt_ff[i]) == NULL) { 2069 continue; 2070 } 2071 if ((fp = ff->ff_file) == NULL) { 2072 continue; 2073 } 2074 2075 mutex_enter(&fp->f_lock); 2076 2077 if ((fp->f_count == 0) || 2078 (fp->f_marker == sysctl_file_marker)) { 2079 mutex_exit(&fp->f_lock); 2080 continue; 2081 } 2082 2083 /* Check that we have enough space. */ 2084 if (buflen < sizeof(struct file)) { 2085 *oldlenp = where - start; 2086 mutex_exit(&fp->f_lock); 2087 error = ENOMEM; 2088 break; 2089 } 2090 2091 memcpy(&fbuf, fp, sizeof(fbuf)); 2092 mutex_exit(&fp->f_lock); 2093 error = sysctl_copyout(l, &fbuf, where, sizeof(fbuf)); 2094 if (error) { 2095 break; 2096 } 2097 buflen -= sizeof(struct file); 2098 where += sizeof(struct file); 2099 2100 fp->f_marker = sysctl_file_marker; 2101 } 2102 mutex_exit(&fd->fd_lock); 2103 2104 /* 2105 * Release reference to process. 2106 */ 2107 mutex_enter(proc_lock); 2108 rw_exit(&p->p_reflock); 2109 2110 if (error) 2111 break; 2112 } 2113 2114 sysctl_file_marker++; 2115 /* Reset all markers if wrapped. */ 2116 if (sysctl_file_marker == 0) { 2117 sysctl_file_marker_reset(); 2118 sysctl_file_marker++; 2119 } 2120 2121 mutex_exit(proc_lock); 2122 mutex_exit(&sysctl_file_marker_lock); 2123 2124 *oldlenp = where - start; 2125 sysctl_relock(); 2126 return error; 2127 } 2128 2129 /* 2130 * sysctl helper function for kern.file2 2131 */ 2132 static int 2133 sysctl_kern_file2(SYSCTLFN_ARGS) 2134 { 2135 struct proc *p; 2136 struct file *fp; 2137 struct filedesc *fd; 2138 struct kinfo_file kf; 2139 char *dp; 2140 u_int i, op; 2141 size_t len, needed, elem_size, out_size; 2142 int error, arg, elem_count; 2143 fdfile_t *ff; 2144 fdtab_t *dt; 2145 2146 if (namelen == 1 && name[0] == CTL_QUERY) 2147 return sysctl_query(SYSCTLFN_CALL(rnode)); 2148 2149 if (namelen != 4) 2150 return EINVAL; 2151 2152 error = 0; 2153 dp = oldp; 2154 len = (oldp != NULL) ? *oldlenp : 0; 2155 op = name[0]; 2156 arg = name[1]; 2157 elem_size = name[2]; 2158 elem_count = name[3]; 2159 out_size = MIN(sizeof(kf), elem_size); 2160 needed = 0; 2161 2162 if (elem_size < 1 || elem_count < 0) 2163 return EINVAL; 2164 2165 switch (op) { 2166 case KERN_FILE_BYFILE: 2167 case KERN_FILE_BYPID: 2168 /* 2169 * We're traversing the process list in both cases; the BYFILE 2170 * case does additional work of keeping track of files already 2171 * looked at. 2172 */ 2173 2174 /* doesn't use arg so it must be zero */ 2175 if ((op == KERN_FILE_BYFILE) && (arg != 0)) 2176 return EINVAL; 2177 2178 if ((op == KERN_FILE_BYPID) && (arg < -1)) 2179 /* -1 means all processes */ 2180 return EINVAL; 2181 2182 sysctl_unlock(); 2183 if (op == KERN_FILE_BYFILE) 2184 mutex_enter(&sysctl_file_marker_lock); 2185 mutex_enter(proc_lock); 2186 PROCLIST_FOREACH(p, &allproc) { 2187 if (p->p_stat == SIDL) { 2188 /* skip embryonic processes */ 2189 continue; 2190 } 2191 if (arg > 0 && p->p_pid != arg) { 2192 /* pick only the one we want */ 2193 /* XXX want 0 to mean "kernel files" */ 2194 continue; 2195 } 2196 mutex_enter(p->p_lock); 2197 error = kauth_authorize_process(l->l_cred, 2198 KAUTH_PROCESS_CANSEE, p, 2199 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES), 2200 NULL, NULL); 2201 mutex_exit(p->p_lock); 2202 if (error != 0) { 2203 /* 2204 * Don't leak kauth retval if we're silently 2205 * skipping this entry. 2206 */ 2207 error = 0; 2208 continue; 2209 } 2210 2211 /* 2212 * Grab a hold on the process. 2213 */ 2214 if (!rw_tryenter(&p->p_reflock, RW_READER)) { 2215 continue; 2216 } 2217 mutex_exit(proc_lock); 2218 2219 fd = p->p_fd; 2220 mutex_enter(&fd->fd_lock); 2221 dt = fd->fd_dt; 2222 for (i = 0; i < dt->dt_nfiles; i++) { 2223 if ((ff = dt->dt_ff[i]) == NULL) { 2224 continue; 2225 } 2226 if ((fp = ff->ff_file) == NULL) { 2227 continue; 2228 } 2229 2230 if ((op == KERN_FILE_BYFILE) && 2231 (fp->f_marker == sysctl_file_marker)) { 2232 continue; 2233 } 2234 if (len >= elem_size && elem_count > 0) { 2235 mutex_enter(&fp->f_lock); 2236 fill_file(&kf, fp, ff, i, p->p_pid); 2237 mutex_exit(&fp->f_lock); 2238 mutex_exit(&fd->fd_lock); 2239 error = sysctl_copyout(l, 2240 &kf, dp, out_size); 2241 mutex_enter(&fd->fd_lock); 2242 if (error) 2243 break; 2244 dp += elem_size; 2245 len -= elem_size; 2246 } 2247 if (op == KERN_FILE_BYFILE) 2248 fp->f_marker = sysctl_file_marker; 2249 needed += elem_size; 2250 if (elem_count > 0 && elem_count != INT_MAX) 2251 elem_count--; 2252 } 2253 mutex_exit(&fd->fd_lock); 2254 2255 /* 2256 * Release reference to process. 2257 */ 2258 mutex_enter(proc_lock); 2259 rw_exit(&p->p_reflock); 2260 } 2261 if (op == KERN_FILE_BYFILE) { 2262 sysctl_file_marker++; 2263 2264 /* Reset all markers if wrapped. */ 2265 if (sysctl_file_marker == 0) { 2266 sysctl_file_marker_reset(); 2267 sysctl_file_marker++; 2268 } 2269 } 2270 mutex_exit(proc_lock); 2271 if (op == KERN_FILE_BYFILE) 2272 mutex_exit(&sysctl_file_marker_lock); 2273 sysctl_relock(); 2274 break; 2275 default: 2276 return EINVAL; 2277 } 2278 2279 if (oldp == NULL) 2280 needed += KERN_FILESLOP * elem_size; 2281 *oldlenp = needed; 2282 2283 return error; 2284 } 2285 2286 static void 2287 fill_file(struct kinfo_file *kp, const file_t *fp, const fdfile_t *ff, 2288 int i, pid_t pid) 2289 { 2290 2291 memset(kp, 0, sizeof(*kp)); 2292 2293 kp->ki_fileaddr = PTRTOUINT64(fp); 2294 kp->ki_flag = fp->f_flag; 2295 kp->ki_iflags = 0; 2296 kp->ki_ftype = fp->f_type; 2297 kp->ki_count = fp->f_count; 2298 kp->ki_msgcount = fp->f_msgcount; 2299 kp->ki_fucred = PTRTOUINT64(fp->f_cred); 2300 kp->ki_fuid = kauth_cred_geteuid(fp->f_cred); 2301 kp->ki_fgid = kauth_cred_getegid(fp->f_cred); 2302 kp->ki_fops = PTRTOUINT64(fp->f_ops); 2303 kp->ki_foffset = fp->f_offset; 2304 kp->ki_fdata = PTRTOUINT64(fp->f_data); 2305 2306 /* vnode information to glue this file to something */ 2307 if (fp->f_type == DTYPE_VNODE) { 2308 struct vnode *vp = fp->f_vnode; 2309 2310 kp->ki_vun = PTRTOUINT64(vp->v_un.vu_socket); 2311 kp->ki_vsize = vp->v_size; 2312 kp->ki_vtype = vp->v_type; 2313 kp->ki_vtag = vp->v_tag; 2314 kp->ki_vdata = PTRTOUINT64(vp->v_data); 2315 } 2316 2317 /* process information when retrieved via KERN_FILE_BYPID */ 2318 if (ff != NULL) { 2319 kp->ki_pid = pid; 2320 kp->ki_fd = i; 2321 kp->ki_ofileflags = ff->ff_exclose; 2322 kp->ki_usecount = ff->ff_refcnt; 2323 } 2324 } 2325