1 /* $NetBSD: kern_descrip.c,v 1.215 2011/06/26 16:42:41 christos 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 1.215 2011/06/26 16:42:41 christos 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 filedescopen, noclose, noread, nowrite, noioctl, 126 nostop, notty, nopoll, nommap, nokqfilter, D_OTHER | D_MPSAFE, 127 }; 128 129 /* For ease of reading. */ 130 __strong_alias(fd_putvnode,fd_putfile) 131 __strong_alias(fd_putsock,fd_putfile) 132 133 /* 134 * Initialize the descriptor system. 135 */ 136 void 137 fd_sys_init(void) 138 { 139 static struct sysctllog *clog; 140 141 mutex_init(&filelist_lock, MUTEX_DEFAULT, IPL_NONE); 142 143 file_cache = pool_cache_init(sizeof(file_t), coherency_unit, 0, 144 0, "file", NULL, IPL_NONE, file_ctor, file_dtor, NULL); 145 KASSERT(file_cache != NULL); 146 147 fdfile_cache = pool_cache_init(sizeof(fdfile_t), coherency_unit, 0, 148 PR_LARGECACHE, "fdfile", NULL, IPL_NONE, fdfile_ctor, fdfile_dtor, 149 NULL); 150 KASSERT(fdfile_cache != NULL); 151 152 filedesc_cache = pool_cache_init(sizeof(filedesc_t), coherency_unit, 153 0, 0, "filedesc", NULL, IPL_NONE, filedesc_ctor, filedesc_dtor, 154 NULL); 155 KASSERT(filedesc_cache != NULL); 156 157 sysctl_createv(&clog, 0, NULL, NULL, 158 CTLFLAG_PERMANENT, CTLTYPE_NODE, "kern", NULL, 159 NULL, 0, NULL, 0, CTL_KERN, CTL_EOL); 160 sysctl_createv(&clog, 0, NULL, NULL, 161 CTLFLAG_PERMANENT, 162 CTLTYPE_STRUCT, "file", 163 SYSCTL_DESCR("System open file table"), 164 sysctl_kern_file, 0, NULL, 0, 165 CTL_KERN, KERN_FILE, CTL_EOL); 166 sysctl_createv(&clog, 0, NULL, NULL, 167 CTLFLAG_PERMANENT, 168 CTLTYPE_STRUCT, "file2", 169 SYSCTL_DESCR("System open file table"), 170 sysctl_kern_file2, 0, NULL, 0, 171 CTL_KERN, KERN_FILE2, CTL_EOL); 172 } 173 174 static bool 175 fd_isused(filedesc_t *fdp, unsigned fd) 176 { 177 u_int off = fd >> NDENTRYSHIFT; 178 179 KASSERT(fd < fdp->fd_dt->dt_nfiles); 180 181 return (fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) != 0; 182 } 183 184 /* 185 * Verify that the bitmaps match the descriptor table. 186 */ 187 static inline void 188 fd_checkmaps(filedesc_t *fdp) 189 { 190 #ifdef DEBUG 191 fdtab_t *dt; 192 u_int fd; 193 194 dt = fdp->fd_dt; 195 if (fdp->fd_refcnt == -1) { 196 /* 197 * fd_free tears down the table without maintaining its bitmap. 198 */ 199 return; 200 } 201 for (fd = 0; fd < dt->dt_nfiles; fd++) { 202 if (fd < NDFDFILE) { 203 KASSERT(dt->dt_ff[fd] == 204 (fdfile_t *)fdp->fd_dfdfile[fd]); 205 } 206 if (dt->dt_ff[fd] == NULL) { 207 KASSERT(!fd_isused(fdp, fd)); 208 } else if (dt->dt_ff[fd]->ff_file != NULL) { 209 KASSERT(fd_isused(fdp, fd)); 210 } 211 } 212 #endif 213 } 214 215 static int 216 fd_next_zero(filedesc_t *fdp, uint32_t *bitmap, int want, u_int bits) 217 { 218 int i, off, maxoff; 219 uint32_t sub; 220 221 KASSERT(mutex_owned(&fdp->fd_lock)); 222 223 fd_checkmaps(fdp); 224 225 if (want > bits) 226 return -1; 227 228 off = want >> NDENTRYSHIFT; 229 i = want & NDENTRYMASK; 230 if (i) { 231 sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i)); 232 if (sub != ~0) 233 goto found; 234 off++; 235 } 236 237 maxoff = NDLOSLOTS(bits); 238 while (off < maxoff) { 239 if ((sub = bitmap[off]) != ~0) 240 goto found; 241 off++; 242 } 243 244 return -1; 245 246 found: 247 return (off << NDENTRYSHIFT) + ffs(~sub) - 1; 248 } 249 250 static int 251 fd_last_set(filedesc_t *fd, int last) 252 { 253 int off, i; 254 fdfile_t **ff = fd->fd_dt->dt_ff; 255 uint32_t *bitmap = fd->fd_lomap; 256 257 KASSERT(mutex_owned(&fd->fd_lock)); 258 259 fd_checkmaps(fd); 260 261 off = (last - 1) >> NDENTRYSHIFT; 262 263 while (off >= 0 && !bitmap[off]) 264 off--; 265 266 if (off < 0) 267 return -1; 268 269 i = ((off + 1) << NDENTRYSHIFT) - 1; 270 if (i >= last) 271 i = last - 1; 272 273 /* XXX should use bitmap */ 274 while (i > 0 && (ff[i] == NULL || !ff[i]->ff_allocated)) 275 i--; 276 277 return i; 278 } 279 280 static inline void 281 fd_used(filedesc_t *fdp, unsigned fd) 282 { 283 u_int off = fd >> NDENTRYSHIFT; 284 fdfile_t *ff; 285 286 ff = fdp->fd_dt->dt_ff[fd]; 287 288 KASSERT(mutex_owned(&fdp->fd_lock)); 289 KASSERT((fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) == 0); 290 KASSERT(ff != NULL); 291 KASSERT(ff->ff_file == NULL); 292 KASSERT(!ff->ff_allocated); 293 294 ff->ff_allocated = 1; 295 fdp->fd_lomap[off] |= 1 << (fd & NDENTRYMASK); 296 if (__predict_false(fdp->fd_lomap[off] == ~0)) { 297 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & 298 (1 << (off & NDENTRYMASK))) == 0); 299 fdp->fd_himap[off >> NDENTRYSHIFT] |= 1 << (off & NDENTRYMASK); 300 } 301 302 if ((int)fd > fdp->fd_lastfile) { 303 fdp->fd_lastfile = fd; 304 } 305 306 fd_checkmaps(fdp); 307 } 308 309 static inline void 310 fd_unused(filedesc_t *fdp, unsigned fd) 311 { 312 u_int off = fd >> NDENTRYSHIFT; 313 fdfile_t *ff; 314 315 ff = fdp->fd_dt->dt_ff[fd]; 316 317 /* 318 * Don't assert the lock is held here, as we may be copying 319 * the table during exec() and it is not needed there. 320 * procfs and sysctl are locked out by proc::p_reflock. 321 * 322 * KASSERT(mutex_owned(&fdp->fd_lock)); 323 */ 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 (1 << (off & NDENTRYMASK))) != 0); 335 fdp->fd_himap[off >> NDENTRYSHIFT] &= 336 ~(1 << (off & NDENTRYMASK)); 337 } 338 KASSERT((fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) != 0); 339 fdp->fd_lomap[off] &= ~(1 << (fd & NDENTRYMASK)); 340 ff->ff_allocated = 0; 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 = 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 atomic_inc_uint(&ff->ff_refcnt); 391 #ifndef __HAVE_ATOMIC_AS_MEMBAR 392 membar_enter(); 393 #endif 394 } 395 396 /* 397 * If the file is not open or is being closed then put the 398 * reference back. 399 */ 400 fp = ff->ff_file; 401 if (__predict_true(fp != NULL)) { 402 return fp; 403 } 404 fd_putfile(fd); 405 return NULL; 406 } 407 408 /* 409 * Release a reference to a file descriptor acquired with fd_getfile(). 410 */ 411 void 412 fd_putfile(unsigned fd) 413 { 414 filedesc_t *fdp; 415 fdfile_t *ff; 416 u_int u, v; 417 418 fdp = curlwp->l_fd; 419 ff = fdp->fd_dt->dt_ff[fd]; 420 421 KASSERT(fd < fdp->fd_dt->dt_nfiles); 422 KASSERT(ff != NULL); 423 KASSERT((ff->ff_refcnt & FR_MASK) > 0); 424 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 425 426 if (fdp->fd_refcnt == 1) { 427 /* 428 * Single threaded: don't need to worry about concurrent 429 * access (other than earlier calls to kqueue, which may 430 * hold a reference to the descriptor). 431 */ 432 if (__predict_false((ff->ff_refcnt & FR_CLOSING) != 0)) { 433 fd_close(fd); 434 return; 435 } 436 ff->ff_refcnt--; 437 return; 438 } 439 440 /* 441 * Ensure that any use of the file is complete and globally 442 * visible before dropping the final reference. If no membar, 443 * the current CPU could still access memory associated with 444 * the file after it has been freed or recycled by another 445 * CPU. 446 */ 447 #ifndef __HAVE_ATOMIC_AS_MEMBAR 448 membar_exit(); 449 #endif 450 451 /* 452 * Be optimistic and start out with the assumption that no other 453 * threads are trying to close the descriptor. If the CAS fails, 454 * we lost a race and/or it's being closed. 455 */ 456 for (u = ff->ff_refcnt & FR_MASK;; u = v) { 457 v = atomic_cas_uint(&ff->ff_refcnt, u, u - 1); 458 if (__predict_true(u == v)) { 459 return; 460 } 461 if (__predict_false((v & FR_CLOSING) != 0)) { 462 break; 463 } 464 } 465 466 /* Another thread is waiting to close the file: join it. */ 467 (void)fd_close(fd); 468 } 469 470 /* 471 * Convenience wrapper around fd_getfile() that returns reference 472 * to a vnode. 473 */ 474 int 475 fd_getvnode(unsigned fd, file_t **fpp) 476 { 477 vnode_t *vp; 478 file_t *fp; 479 480 fp = fd_getfile(fd); 481 if (__predict_false(fp == NULL)) { 482 return EBADF; 483 } 484 if (__predict_false(fp->f_type != DTYPE_VNODE)) { 485 fd_putfile(fd); 486 return EINVAL; 487 } 488 vp = fp->f_data; 489 if (__predict_false(vp->v_type == VBAD)) { 490 /* XXX Is this case really necessary? */ 491 fd_putfile(fd); 492 return EBADF; 493 } 494 *fpp = fp; 495 return 0; 496 } 497 498 /* 499 * Convenience wrapper around fd_getfile() that returns reference 500 * to a socket. 501 */ 502 int 503 fd_getsock(unsigned fd, struct socket **sop) 504 { 505 file_t *fp; 506 507 fp = fd_getfile(fd); 508 if (__predict_false(fp == NULL)) { 509 return EBADF; 510 } 511 if (__predict_false(fp->f_type != DTYPE_SOCKET)) { 512 fd_putfile(fd); 513 return ENOTSOCK; 514 } 515 *sop = fp->f_data; 516 return 0; 517 } 518 519 /* 520 * Look up the file structure corresponding to a file descriptor 521 * and return it with a reference held on the file, not the 522 * descriptor. 523 * 524 * This is heavyweight and only used when accessing descriptors 525 * from a foreign process. The caller must ensure that `p' does 526 * not exit or fork across this call. 527 * 528 * To release the file (not descriptor) reference, use closef(). 529 */ 530 file_t * 531 fd_getfile2(proc_t *p, unsigned fd) 532 { 533 filedesc_t *fdp; 534 fdfile_t *ff; 535 file_t *fp; 536 fdtab_t *dt; 537 538 fdp = p->p_fd; 539 mutex_enter(&fdp->fd_lock); 540 dt = fdp->fd_dt; 541 if (fd >= dt->dt_nfiles) { 542 mutex_exit(&fdp->fd_lock); 543 return NULL; 544 } 545 if ((ff = dt->dt_ff[fd]) == NULL) { 546 mutex_exit(&fdp->fd_lock); 547 return NULL; 548 } 549 if ((fp = ff->ff_file) == NULL) { 550 mutex_exit(&fdp->fd_lock); 551 return NULL; 552 } 553 mutex_enter(&fp->f_lock); 554 fp->f_count++; 555 mutex_exit(&fp->f_lock); 556 mutex_exit(&fdp->fd_lock); 557 558 return fp; 559 } 560 561 /* 562 * Internal form of close. Must be called with a reference to the 563 * descriptor, and will drop the reference. When all descriptor 564 * references are dropped, releases the descriptor slot and a single 565 * reference to the file structure. 566 */ 567 int 568 fd_close(unsigned fd) 569 { 570 struct flock lf; 571 filedesc_t *fdp; 572 fdfile_t *ff; 573 file_t *fp; 574 proc_t *p; 575 lwp_t *l; 576 u_int refcnt; 577 578 l = curlwp; 579 p = l->l_proc; 580 fdp = l->l_fd; 581 ff = fdp->fd_dt->dt_ff[fd]; 582 583 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 584 585 mutex_enter(&fdp->fd_lock); 586 KASSERT((ff->ff_refcnt & FR_MASK) > 0); 587 if (__predict_false(ff->ff_file == NULL)) { 588 /* 589 * Another user of the file is already closing, and is 590 * waiting for other users of the file to drain. Release 591 * our reference, and wake up the closer. 592 */ 593 atomic_dec_uint(&ff->ff_refcnt); 594 cv_broadcast(&ff->ff_closing); 595 mutex_exit(&fdp->fd_lock); 596 597 /* 598 * An application error, so pretend that the descriptor 599 * was already closed. We can't safely wait for it to 600 * be closed without potentially deadlocking. 601 */ 602 return (EBADF); 603 } 604 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); 605 606 /* 607 * There may be multiple users of this file within the process. 608 * Notify existing and new users that the file is closing. This 609 * will prevent them from adding additional uses to this file 610 * while we are closing it. 611 */ 612 fp = ff->ff_file; 613 ff->ff_file = NULL; 614 ff->ff_exclose = false; 615 616 /* 617 * We expect the caller to hold a descriptor reference - drop it. 618 * The reference count may increase beyond zero at this point due 619 * to an erroneous descriptor reference by an application, but 620 * fd_getfile() will notice that the file is being closed and drop 621 * the reference again. 622 */ 623 if (fdp->fd_refcnt == 1) { 624 /* Single threaded. */ 625 refcnt = --(ff->ff_refcnt); 626 } else { 627 /* Multi threaded. */ 628 #ifndef __HAVE_ATOMIC_AS_MEMBAR 629 membar_producer(); 630 #endif 631 refcnt = atomic_dec_uint_nv(&ff->ff_refcnt); 632 } 633 if (__predict_false(refcnt != 0)) { 634 /* 635 * Wait for other references to drain. This is typically 636 * an application error - the descriptor is being closed 637 * while still in use. 638 * (Or just a threaded application trying to unblock its 639 * thread that sleeps in (say) accept()). 640 */ 641 atomic_or_uint(&ff->ff_refcnt, FR_CLOSING); 642 643 /* 644 * Remove any knotes attached to the file. A knote 645 * attached to the descriptor can hold references on it. 646 */ 647 mutex_exit(&fdp->fd_lock); 648 if (!SLIST_EMPTY(&ff->ff_knlist)) { 649 knote_fdclose(fd); 650 } 651 652 /* 653 * Since the file system code doesn't know which fd 654 * each request came from (think dup()), we have to 655 * ask it to return ERESTART for any long-term blocks. 656 * The re-entry through read/write/etc will detect the 657 * closed fd and return EBAFD. 658 * Blocked partial writes may return a short length. 659 */ 660 (*fp->f_ops->fo_restart)(fp); 661 mutex_enter(&fdp->fd_lock); 662 663 /* 664 * We need to see the count drop to zero at least once, 665 * in order to ensure that all pre-existing references 666 * have been drained. New references past this point are 667 * of no interest. 668 * XXX (dsl) this may need to call fo_restart() after a 669 * timeout to guarantee that all the system calls exit. 670 */ 671 while ((ff->ff_refcnt & FR_MASK) != 0) { 672 cv_wait(&ff->ff_closing, &fdp->fd_lock); 673 } 674 atomic_and_uint(&ff->ff_refcnt, ~FR_CLOSING); 675 } else { 676 /* If no references, there must be no knotes. */ 677 KASSERT(SLIST_EMPTY(&ff->ff_knlist)); 678 } 679 680 /* 681 * POSIX record locking dictates that any close releases ALL 682 * locks owned by this process. This is handled by setting 683 * a flag in the unlock to free ONLY locks obeying POSIX 684 * semantics, and not to free BSD-style file locks. 685 * If the descriptor was in a message, POSIX-style locks 686 * aren't passed with the descriptor. 687 */ 688 if (__predict_false((p->p_flag & PK_ADVLOCK) != 0 && 689 fp->f_type == DTYPE_VNODE)) { 690 lf.l_whence = SEEK_SET; 691 lf.l_start = 0; 692 lf.l_len = 0; 693 lf.l_type = F_UNLCK; 694 mutex_exit(&fdp->fd_lock); 695 (void)VOP_ADVLOCK(fp->f_data, p, F_UNLCK, &lf, F_POSIX); 696 mutex_enter(&fdp->fd_lock); 697 } 698 699 /* Free descriptor slot. */ 700 fd_unused(fdp, fd); 701 mutex_exit(&fdp->fd_lock); 702 703 /* Now drop reference to the file itself. */ 704 return closef(fp); 705 } 706 707 /* 708 * Duplicate a file descriptor. 709 */ 710 int 711 fd_dup(file_t *fp, int minfd, int *newp, bool exclose) 712 { 713 proc_t *p = curproc; 714 int error; 715 716 while ((error = fd_alloc(p, minfd, newp)) != 0) { 717 if (error != ENOSPC) { 718 return error; 719 } 720 fd_tryexpand(p); 721 } 722 723 curlwp->l_fd->fd_dt->dt_ff[*newp]->ff_exclose = exclose; 724 fd_affix(p, fp, *newp); 725 return 0; 726 } 727 728 /* 729 * dup2 operation. 730 */ 731 int 732 fd_dup2(file_t *fp, unsigned new, int flags) 733 { 734 filedesc_t *fdp = curlwp->l_fd; 735 fdfile_t *ff; 736 fdtab_t *dt; 737 738 /* 739 * Ensure there are enough slots in the descriptor table, 740 * and allocate an fdfile_t up front in case we need it. 741 */ 742 while (new >= fdp->fd_dt->dt_nfiles) { 743 fd_tryexpand(curproc); 744 } 745 ff = pool_cache_get(fdfile_cache, PR_WAITOK); 746 747 /* 748 * If there is already a file open, close it. If the file is 749 * half open, wait for it to be constructed before closing it. 750 * XXX Potential for deadlock here? 751 */ 752 mutex_enter(&fdp->fd_lock); 753 while (fd_isused(fdp, new)) { 754 mutex_exit(&fdp->fd_lock); 755 if (fd_getfile(new) != NULL) { 756 (void)fd_close(new); 757 } else { 758 /* 759 * Crummy, but unlikely to happen. 760 * Can occur if we interrupt another 761 * thread while it is opening a file. 762 */ 763 kpause("dup2", false, 1, NULL); 764 } 765 mutex_enter(&fdp->fd_lock); 766 } 767 dt = fdp->fd_dt; 768 if (dt->dt_ff[new] == NULL) { 769 KASSERT(new >= NDFDFILE); 770 dt->dt_ff[new] = ff; 771 ff = NULL; 772 } 773 fd_used(fdp, new); 774 mutex_exit(&fdp->fd_lock); 775 776 dt->dt_ff[new]->ff_exclose = (flags & O_CLOEXEC) != 0; 777 fp->f_flag |= flags & FNONBLOCK; 778 /* Slot is now allocated. Insert copy of the file. */ 779 fd_affix(curproc, fp, new); 780 if (ff != NULL) { 781 pool_cache_put(fdfile_cache, ff); 782 } 783 return 0; 784 } 785 786 /* 787 * Drop reference to a file structure. 788 */ 789 int 790 closef(file_t *fp) 791 { 792 struct flock lf; 793 int error; 794 795 /* 796 * Drop reference. If referenced elsewhere it's still open 797 * and we have nothing more to do. 798 */ 799 mutex_enter(&fp->f_lock); 800 KASSERT(fp->f_count > 0); 801 if (--fp->f_count > 0) { 802 mutex_exit(&fp->f_lock); 803 return 0; 804 } 805 KASSERT(fp->f_count == 0); 806 mutex_exit(&fp->f_lock); 807 808 /* We held the last reference - release locks, close and free. */ 809 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) { 810 lf.l_whence = SEEK_SET; 811 lf.l_start = 0; 812 lf.l_len = 0; 813 lf.l_type = F_UNLCK; 814 (void)VOP_ADVLOCK(fp->f_data, fp, F_UNLCK, &lf, F_FLOCK); 815 } 816 if (fp->f_ops != NULL) { 817 error = (*fp->f_ops->fo_close)(fp); 818 } else { 819 error = 0; 820 } 821 KASSERT(fp->f_count == 0); 822 KASSERT(fp->f_cred != NULL); 823 pool_cache_put(file_cache, fp); 824 825 return error; 826 } 827 828 /* 829 * Allocate a file descriptor for the process. 830 */ 831 int 832 fd_alloc(proc_t *p, int want, int *result) 833 { 834 filedesc_t *fdp = p->p_fd; 835 int i, lim, last, error; 836 u_int off, new; 837 fdtab_t *dt; 838 839 KASSERT(p == curproc || p == &proc0); 840 841 /* 842 * Search for a free descriptor starting at the higher 843 * of want or fd_freefile. 844 */ 845 mutex_enter(&fdp->fd_lock); 846 fd_checkmaps(fdp); 847 dt = fdp->fd_dt; 848 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 849 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles); 850 last = min(dt->dt_nfiles, lim); 851 for (;;) { 852 if ((i = want) < fdp->fd_freefile) 853 i = fdp->fd_freefile; 854 off = i >> NDENTRYSHIFT; 855 new = fd_next_zero(fdp, fdp->fd_himap, off, 856 (last + NDENTRIES - 1) >> NDENTRYSHIFT); 857 if (new == -1) 858 break; 859 i = fd_next_zero(fdp, &fdp->fd_lomap[new], 860 new > off ? 0 : i & NDENTRYMASK, NDENTRIES); 861 if (i == -1) { 862 /* 863 * Free file descriptor in this block was 864 * below want, try again with higher want. 865 */ 866 want = (new + 1) << NDENTRYSHIFT; 867 continue; 868 } 869 i += (new << NDENTRYSHIFT); 870 if (i >= last) { 871 break; 872 } 873 if (dt->dt_ff[i] == NULL) { 874 KASSERT(i >= NDFDFILE); 875 dt->dt_ff[i] = pool_cache_get(fdfile_cache, PR_WAITOK); 876 } 877 KASSERT(dt->dt_ff[i]->ff_file == NULL); 878 fd_used(fdp, i); 879 if (want <= fdp->fd_freefile) { 880 fdp->fd_freefile = i; 881 } 882 *result = i; 883 KASSERT(i >= NDFDFILE || 884 dt->dt_ff[i] == (fdfile_t *)fdp->fd_dfdfile[i]); 885 fd_checkmaps(fdp); 886 mutex_exit(&fdp->fd_lock); 887 return 0; 888 } 889 890 /* No space in current array. Let the caller expand and retry. */ 891 error = (dt->dt_nfiles >= lim) ? EMFILE : ENOSPC; 892 mutex_exit(&fdp->fd_lock); 893 return error; 894 } 895 896 /* 897 * Allocate memory for a descriptor table. 898 */ 899 static fdtab_t * 900 fd_dtab_alloc(int n) 901 { 902 fdtab_t *dt; 903 size_t sz; 904 905 KASSERT(n > NDFILE); 906 907 sz = sizeof(*dt) + (n - NDFILE) * sizeof(dt->dt_ff[0]); 908 dt = kmem_alloc(sz, KM_SLEEP); 909 #ifdef DIAGNOSTIC 910 memset(dt, 0xff, sz); 911 #endif 912 dt->dt_nfiles = n; 913 dt->dt_link = NULL; 914 return dt; 915 } 916 917 /* 918 * Free a descriptor table, and all tables linked for deferred free. 919 */ 920 static void 921 fd_dtab_free(fdtab_t *dt) 922 { 923 fdtab_t *next; 924 size_t sz; 925 926 do { 927 next = dt->dt_link; 928 KASSERT(dt->dt_nfiles > NDFILE); 929 sz = sizeof(*dt) + 930 (dt->dt_nfiles - NDFILE) * sizeof(dt->dt_ff[0]); 931 #ifdef DIAGNOSTIC 932 memset(dt, 0xff, sz); 933 #endif 934 kmem_free(dt, sz); 935 dt = next; 936 } while (dt != NULL); 937 } 938 939 /* 940 * Allocate descriptor bitmap. 941 */ 942 static void 943 fd_map_alloc(int n, uint32_t **lo, uint32_t **hi) 944 { 945 uint8_t *ptr; 946 size_t szlo, szhi; 947 948 KASSERT(n > NDENTRIES); 949 950 szlo = NDLOSLOTS(n) * sizeof(uint32_t); 951 szhi = NDHISLOTS(n) * sizeof(uint32_t); 952 ptr = kmem_alloc(szlo + szhi, KM_SLEEP); 953 *lo = (uint32_t *)ptr; 954 *hi = (uint32_t *)(ptr + szlo); 955 } 956 957 /* 958 * Free descriptor bitmap. 959 */ 960 static void 961 fd_map_free(int n, uint32_t *lo, uint32_t *hi) 962 { 963 size_t szlo, szhi; 964 965 KASSERT(n > NDENTRIES); 966 967 szlo = NDLOSLOTS(n) * sizeof(uint32_t); 968 szhi = NDHISLOTS(n) * sizeof(uint32_t); 969 KASSERT(hi == (uint32_t *)((uint8_t *)lo + szlo)); 970 kmem_free(lo, szlo + szhi); 971 } 972 973 /* 974 * Expand a process' descriptor table. 975 */ 976 void 977 fd_tryexpand(proc_t *p) 978 { 979 filedesc_t *fdp; 980 int i, numfiles, oldnfiles; 981 fdtab_t *newdt, *dt; 982 uint32_t *newhimap, *newlomap; 983 984 KASSERT(p == curproc || p == &proc0); 985 986 fdp = p->p_fd; 987 newhimap = NULL; 988 newlomap = NULL; 989 oldnfiles = fdp->fd_dt->dt_nfiles; 990 991 if (oldnfiles < NDEXTENT) 992 numfiles = NDEXTENT; 993 else 994 numfiles = 2 * oldnfiles; 995 996 newdt = fd_dtab_alloc(numfiles); 997 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 998 fd_map_alloc(numfiles, &newlomap, &newhimap); 999 } 1000 1001 mutex_enter(&fdp->fd_lock); 1002 dt = fdp->fd_dt; 1003 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1004 if (dt->dt_nfiles != oldnfiles) { 1005 /* fdp changed; caller must retry */ 1006 mutex_exit(&fdp->fd_lock); 1007 fd_dtab_free(newdt); 1008 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1009 fd_map_free(numfiles, newlomap, newhimap); 1010 } 1011 return; 1012 } 1013 1014 /* Copy the existing descriptor table and zero the new portion. */ 1015 i = sizeof(fdfile_t *) * oldnfiles; 1016 memcpy(newdt->dt_ff, dt->dt_ff, i); 1017 memset((uint8_t *)newdt->dt_ff + i, 0, 1018 numfiles * sizeof(fdfile_t *) - i); 1019 1020 /* 1021 * Link old descriptor array into list to be discarded. We defer 1022 * freeing until the last reference to the descriptor table goes 1023 * away (usually process exit). This allows us to do lockless 1024 * lookups in fd_getfile(). 1025 */ 1026 if (oldnfiles > NDFILE) { 1027 if (fdp->fd_refcnt > 1) { 1028 newdt->dt_link = dt; 1029 } else { 1030 fd_dtab_free(dt); 1031 } 1032 } 1033 1034 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1035 i = NDHISLOTS(oldnfiles) * sizeof(uint32_t); 1036 memcpy(newhimap, fdp->fd_himap, i); 1037 memset((uint8_t *)newhimap + i, 0, 1038 NDHISLOTS(numfiles) * sizeof(uint32_t) - i); 1039 1040 i = NDLOSLOTS(oldnfiles) * sizeof(uint32_t); 1041 memcpy(newlomap, fdp->fd_lomap, i); 1042 memset((uint8_t *)newlomap + i, 0, 1043 NDLOSLOTS(numfiles) * sizeof(uint32_t) - i); 1044 1045 if (NDHISLOTS(oldnfiles) > NDHISLOTS(NDFILE)) { 1046 fd_map_free(oldnfiles, fdp->fd_lomap, fdp->fd_himap); 1047 } 1048 fdp->fd_himap = newhimap; 1049 fdp->fd_lomap = newlomap; 1050 } 1051 1052 /* 1053 * All other modifications must become globally visible before 1054 * the change to fd_dt. See fd_getfile(). 1055 */ 1056 membar_producer(); 1057 fdp->fd_dt = newdt; 1058 KASSERT(newdt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1059 fd_checkmaps(fdp); 1060 mutex_exit(&fdp->fd_lock); 1061 } 1062 1063 /* 1064 * Create a new open file structure and allocate a file descriptor 1065 * for the current process. 1066 */ 1067 int 1068 fd_allocfile(file_t **resultfp, int *resultfd) 1069 { 1070 proc_t *p = curproc; 1071 kauth_cred_t cred; 1072 file_t *fp; 1073 int error; 1074 1075 while ((error = fd_alloc(p, 0, resultfd)) != 0) { 1076 if (error != ENOSPC) { 1077 return error; 1078 } 1079 fd_tryexpand(p); 1080 } 1081 1082 fp = pool_cache_get(file_cache, PR_WAITOK); 1083 if (fp == NULL) { 1084 return ENFILE; 1085 } 1086 KASSERT(fp->f_count == 0); 1087 KASSERT(fp->f_msgcount == 0); 1088 KASSERT(fp->f_unpcount == 0); 1089 1090 /* Replace cached credentials if not what we need. */ 1091 cred = curlwp->l_cred; 1092 if (__predict_false(cred != fp->f_cred)) { 1093 kauth_cred_free(fp->f_cred); 1094 kauth_cred_hold(cred); 1095 fp->f_cred = cred; 1096 } 1097 1098 /* 1099 * Don't allow recycled files to be scanned. 1100 * See uipc_usrreq.c. 1101 */ 1102 if (__predict_false((fp->f_flag & FSCAN) != 0)) { 1103 mutex_enter(&fp->f_lock); 1104 atomic_and_uint(&fp->f_flag, ~FSCAN); 1105 mutex_exit(&fp->f_lock); 1106 } 1107 1108 fp->f_advice = 0; 1109 fp->f_offset = 0; 1110 *resultfp = fp; 1111 1112 return 0; 1113 } 1114 1115 /* 1116 * Successful creation of a new descriptor: make visible to the process. 1117 */ 1118 void 1119 fd_affix(proc_t *p, file_t *fp, unsigned fd) 1120 { 1121 fdfile_t *ff; 1122 filedesc_t *fdp; 1123 1124 KASSERT(p == curproc || p == &proc0); 1125 1126 /* Add a reference to the file structure. */ 1127 mutex_enter(&fp->f_lock); 1128 fp->f_count++; 1129 mutex_exit(&fp->f_lock); 1130 1131 /* 1132 * Insert the new file into the descriptor slot. 1133 * 1134 * The memory barriers provided by lock activity in this routine 1135 * ensure that any updates to the file structure become globally 1136 * visible before the file becomes visible to other LWPs in the 1137 * current process. 1138 */ 1139 fdp = p->p_fd; 1140 ff = fdp->fd_dt->dt_ff[fd]; 1141 1142 KASSERT(ff != NULL); 1143 KASSERT(ff->ff_file == NULL); 1144 KASSERT(ff->ff_allocated); 1145 KASSERT(fd_isused(fdp, fd)); 1146 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1147 1148 /* No need to lock in order to make file initially visible. */ 1149 ff->ff_file = fp; 1150 } 1151 1152 /* 1153 * Abort creation of a new descriptor: free descriptor slot and file. 1154 */ 1155 void 1156 fd_abort(proc_t *p, file_t *fp, unsigned fd) 1157 { 1158 filedesc_t *fdp; 1159 fdfile_t *ff; 1160 1161 KASSERT(p == curproc || p == &proc0); 1162 1163 fdp = p->p_fd; 1164 ff = fdp->fd_dt->dt_ff[fd]; 1165 1166 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1167 1168 mutex_enter(&fdp->fd_lock); 1169 KASSERT(fd_isused(fdp, fd)); 1170 fd_unused(fdp, fd); 1171 mutex_exit(&fdp->fd_lock); 1172 1173 if (fp != NULL) { 1174 KASSERT(fp->f_count == 0); 1175 KASSERT(fp->f_cred != NULL); 1176 pool_cache_put(file_cache, fp); 1177 } 1178 } 1179 1180 static int 1181 file_ctor(void *arg, void *obj, int flags) 1182 { 1183 file_t *fp = obj; 1184 1185 memset(fp, 0, sizeof(*fp)); 1186 1187 mutex_enter(&filelist_lock); 1188 if (__predict_false(nfiles >= maxfiles)) { 1189 mutex_exit(&filelist_lock); 1190 tablefull("file", "increase kern.maxfiles or MAXFILES"); 1191 return ENFILE; 1192 } 1193 nfiles++; 1194 LIST_INSERT_HEAD(&filehead, fp, f_list); 1195 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); 1196 fp->f_cred = curlwp->l_cred; 1197 kauth_cred_hold(fp->f_cred); 1198 mutex_exit(&filelist_lock); 1199 1200 return 0; 1201 } 1202 1203 static void 1204 file_dtor(void *arg, void *obj) 1205 { 1206 file_t *fp = obj; 1207 1208 mutex_enter(&filelist_lock); 1209 nfiles--; 1210 LIST_REMOVE(fp, f_list); 1211 mutex_exit(&filelist_lock); 1212 1213 kauth_cred_free(fp->f_cred); 1214 mutex_destroy(&fp->f_lock); 1215 } 1216 1217 static int 1218 fdfile_ctor(void *arg, void *obj, int flags) 1219 { 1220 fdfile_t *ff = obj; 1221 1222 memset(ff, 0, sizeof(*ff)); 1223 cv_init(&ff->ff_closing, "fdclose"); 1224 1225 return 0; 1226 } 1227 1228 static void 1229 fdfile_dtor(void *arg, void *obj) 1230 { 1231 fdfile_t *ff = obj; 1232 1233 cv_destroy(&ff->ff_closing); 1234 } 1235 1236 file_t * 1237 fgetdummy(void) 1238 { 1239 file_t *fp; 1240 1241 fp = kmem_zalloc(sizeof(*fp), KM_SLEEP); 1242 if (fp != NULL) { 1243 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); 1244 } 1245 return fp; 1246 } 1247 1248 void 1249 fputdummy(file_t *fp) 1250 { 1251 1252 mutex_destroy(&fp->f_lock); 1253 kmem_free(fp, sizeof(*fp)); 1254 } 1255 1256 /* 1257 * Create an initial filedesc structure. 1258 */ 1259 filedesc_t * 1260 fd_init(filedesc_t *fdp) 1261 { 1262 #ifdef DIAGNOSTIC 1263 unsigned fd; 1264 #endif 1265 1266 if (__predict_true(fdp == NULL)) { 1267 fdp = pool_cache_get(filedesc_cache, PR_WAITOK); 1268 } else { 1269 KASSERT(fdp == &filedesc0); 1270 filedesc_ctor(NULL, fdp, PR_WAITOK); 1271 } 1272 1273 #ifdef DIAGNOSTIC 1274 KASSERT(fdp->fd_lastfile == -1); 1275 KASSERT(fdp->fd_lastkqfile == -1); 1276 KASSERT(fdp->fd_knhash == NULL); 1277 KASSERT(fdp->fd_freefile == 0); 1278 KASSERT(fdp->fd_exclose == false); 1279 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin); 1280 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1281 for (fd = 0; fd < NDFDFILE; fd++) { 1282 KASSERT(fdp->fd_dtbuiltin.dt_ff[fd] == 1283 (fdfile_t *)fdp->fd_dfdfile[fd]); 1284 } 1285 for (fd = NDFDFILE; fd < NDFILE; fd++) { 1286 KASSERT(fdp->fd_dtbuiltin.dt_ff[fd] == NULL); 1287 } 1288 KASSERT(fdp->fd_himap == fdp->fd_dhimap); 1289 KASSERT(fdp->fd_lomap == fdp->fd_dlomap); 1290 #endif /* DIAGNOSTIC */ 1291 1292 fdp->fd_refcnt = 1; 1293 fd_checkmaps(fdp); 1294 1295 return fdp; 1296 } 1297 1298 /* 1299 * Initialize a file descriptor table. 1300 */ 1301 static int 1302 filedesc_ctor(void *arg, void *obj, int flag) 1303 { 1304 filedesc_t *fdp = obj; 1305 fdfile_t **ffp; 1306 int i; 1307 1308 memset(fdp, 0, sizeof(*fdp)); 1309 mutex_init(&fdp->fd_lock, MUTEX_DEFAULT, IPL_NONE); 1310 fdp->fd_lastfile = -1; 1311 fdp->fd_lastkqfile = -1; 1312 fdp->fd_dt = &fdp->fd_dtbuiltin; 1313 fdp->fd_dtbuiltin.dt_nfiles = NDFILE; 1314 fdp->fd_himap = fdp->fd_dhimap; 1315 fdp->fd_lomap = fdp->fd_dlomap; 1316 1317 CTASSERT(sizeof(fdp->fd_dfdfile[0]) >= sizeof(fdfile_t)); 1318 for (i = 0, ffp = fdp->fd_dt->dt_ff; i < NDFDFILE; i++, ffp++) { 1319 *ffp = (fdfile_t *)fdp->fd_dfdfile[i]; 1320 (void)fdfile_ctor(NULL, fdp->fd_dfdfile[i], PR_WAITOK); 1321 } 1322 1323 return 0; 1324 } 1325 1326 static void 1327 filedesc_dtor(void *arg, void *obj) 1328 { 1329 filedesc_t *fdp = obj; 1330 int i; 1331 1332 for (i = 0; i < NDFDFILE; i++) { 1333 fdfile_dtor(NULL, fdp->fd_dfdfile[i]); 1334 } 1335 1336 mutex_destroy(&fdp->fd_lock); 1337 } 1338 1339 /* 1340 * Make p share curproc's filedesc structure. 1341 */ 1342 void 1343 fd_share(struct proc *p) 1344 { 1345 filedesc_t *fdp; 1346 1347 fdp = curlwp->l_fd; 1348 p->p_fd = fdp; 1349 atomic_inc_uint(&fdp->fd_refcnt); 1350 } 1351 1352 /* 1353 * Acquire a hold on a filedesc structure. 1354 */ 1355 void 1356 fd_hold(lwp_t *l) 1357 { 1358 filedesc_t *fdp = l->l_fd; 1359 1360 atomic_inc_uint(&fdp->fd_refcnt); 1361 } 1362 1363 /* 1364 * Copy a filedesc structure. 1365 */ 1366 filedesc_t * 1367 fd_copy(void) 1368 { 1369 filedesc_t *newfdp, *fdp; 1370 fdfile_t *ff, **ffp, **nffp, *ff2; 1371 int i, j, numfiles, lastfile, newlast; 1372 file_t *fp; 1373 fdtab_t *newdt; 1374 1375 fdp = curproc->p_fd; 1376 newfdp = pool_cache_get(filedesc_cache, PR_WAITOK); 1377 newfdp->fd_refcnt = 1; 1378 1379 #ifdef DIAGNOSTIC 1380 KASSERT(newfdp->fd_lastfile == -1); 1381 KASSERT(newfdp->fd_lastkqfile == -1); 1382 KASSERT(newfdp->fd_knhash == NULL); 1383 KASSERT(newfdp->fd_freefile == 0); 1384 KASSERT(newfdp->fd_exclose == false); 1385 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin); 1386 KASSERT(newfdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1387 for (i = 0; i < NDFDFILE; i++) { 1388 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == 1389 (fdfile_t *)&newfdp->fd_dfdfile[i]); 1390 } 1391 for (i = NDFDFILE; i < NDFILE; i++) { 1392 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == NULL); 1393 } 1394 #endif /* DIAGNOSTIC */ 1395 1396 mutex_enter(&fdp->fd_lock); 1397 fd_checkmaps(fdp); 1398 numfiles = fdp->fd_dt->dt_nfiles; 1399 lastfile = fdp->fd_lastfile; 1400 1401 /* 1402 * If the number of open files fits in the internal arrays 1403 * of the open file structure, use them, otherwise allocate 1404 * additional memory for the number of descriptors currently 1405 * in use. 1406 */ 1407 if (lastfile < NDFILE) { 1408 i = NDFILE; 1409 newdt = newfdp->fd_dt; 1410 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin); 1411 } else { 1412 /* 1413 * Compute the smallest multiple of NDEXTENT needed 1414 * for the file descriptors currently in use, 1415 * allowing the table to shrink. 1416 */ 1417 i = numfiles; 1418 while (i >= 2 * NDEXTENT && i > lastfile * 2) { 1419 i /= 2; 1420 } 1421 KASSERT(i > NDFILE); 1422 newdt = fd_dtab_alloc(i); 1423 newfdp->fd_dt = newdt; 1424 memcpy(newdt->dt_ff, newfdp->fd_dtbuiltin.dt_ff, 1425 NDFDFILE * sizeof(fdfile_t **)); 1426 memset(newdt->dt_ff + NDFDFILE, 0, 1427 (i - NDFDFILE) * sizeof(fdfile_t **)); 1428 } 1429 if (NDHISLOTS(i) <= NDHISLOTS(NDFILE)) { 1430 newfdp->fd_himap = newfdp->fd_dhimap; 1431 newfdp->fd_lomap = newfdp->fd_dlomap; 1432 } else { 1433 fd_map_alloc(i, &newfdp->fd_lomap, &newfdp->fd_himap); 1434 KASSERT(i >= NDENTRIES * NDENTRIES); 1435 memset(newfdp->fd_himap, 0, NDHISLOTS(i)*sizeof(uint32_t)); 1436 memset(newfdp->fd_lomap, 0, NDLOSLOTS(i)*sizeof(uint32_t)); 1437 } 1438 newfdp->fd_freefile = fdp->fd_freefile; 1439 newfdp->fd_exclose = fdp->fd_exclose; 1440 1441 ffp = fdp->fd_dt->dt_ff; 1442 nffp = newdt->dt_ff; 1443 newlast = -1; 1444 for (i = 0; i <= (int)lastfile; i++, ffp++, nffp++) { 1445 KASSERT(i >= NDFDFILE || 1446 *nffp == (fdfile_t *)newfdp->fd_dfdfile[i]); 1447 ff = *ffp; 1448 if (ff == NULL || (fp = ff->ff_file) == NULL) { 1449 /* Descriptor unused, or descriptor half open. */ 1450 KASSERT(!fd_isused(newfdp, i)); 1451 continue; 1452 } 1453 if (__predict_false(fp->f_type == DTYPE_KQUEUE)) { 1454 /* kqueue descriptors cannot be copied. */ 1455 if (i < newfdp->fd_freefile) { 1456 newfdp->fd_freefile = i; 1457 } 1458 continue; 1459 } 1460 /* It's active: add a reference to the file. */ 1461 mutex_enter(&fp->f_lock); 1462 fp->f_count++; 1463 mutex_exit(&fp->f_lock); 1464 1465 /* Allocate an fdfile_t to represent it. */ 1466 if (i >= NDFDFILE) { 1467 ff2 = pool_cache_get(fdfile_cache, PR_WAITOK); 1468 *nffp = ff2; 1469 } else { 1470 ff2 = newdt->dt_ff[i]; 1471 } 1472 ff2->ff_file = fp; 1473 ff2->ff_exclose = ff->ff_exclose; 1474 ff2->ff_allocated = true; 1475 1476 /* Fix up bitmaps. */ 1477 j = i >> NDENTRYSHIFT; 1478 KASSERT((newfdp->fd_lomap[j] & (1 << (i & NDENTRYMASK))) == 0); 1479 newfdp->fd_lomap[j] |= 1 << (i & NDENTRYMASK); 1480 if (__predict_false(newfdp->fd_lomap[j] == ~0)) { 1481 KASSERT((newfdp->fd_himap[j >> NDENTRYSHIFT] & 1482 (1 << (j & NDENTRYMASK))) == 0); 1483 newfdp->fd_himap[j >> NDENTRYSHIFT] |= 1484 1 << (j & NDENTRYMASK); 1485 } 1486 newlast = i; 1487 } 1488 KASSERT(newdt->dt_ff[0] == (fdfile_t *)newfdp->fd_dfdfile[0]); 1489 newfdp->fd_lastfile = newlast; 1490 fd_checkmaps(newfdp); 1491 mutex_exit(&fdp->fd_lock); 1492 1493 return newfdp; 1494 } 1495 1496 /* 1497 * Release a filedesc structure. 1498 */ 1499 void 1500 fd_free(void) 1501 { 1502 fdfile_t *ff; 1503 file_t *fp; 1504 int fd, nf; 1505 fdtab_t *dt; 1506 lwp_t * const l = curlwp; 1507 filedesc_t * const fdp = l->l_fd; 1508 const bool noadvlock = (l->l_proc->p_flag & PK_ADVLOCK) == 0; 1509 1510 KASSERT(fdp->fd_dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1511 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1512 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL); 1513 1514 #ifndef __HAVE_ATOMIC_AS_MEMBAR 1515 membar_exit(); 1516 #endif 1517 if (atomic_dec_uint_nv(&fdp->fd_refcnt) > 0) 1518 return; 1519 1520 /* 1521 * Close any files that the process holds open. 1522 */ 1523 dt = fdp->fd_dt; 1524 fd_checkmaps(fdp); 1525 #ifdef DEBUG 1526 fdp->fd_refcnt = -1; /* see fd_checkmaps */ 1527 #endif 1528 for (fd = 0, nf = dt->dt_nfiles; fd < nf; fd++) { 1529 ff = dt->dt_ff[fd]; 1530 KASSERT(fd >= NDFDFILE || 1531 ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1532 if (ff == NULL) 1533 continue; 1534 if ((fp = ff->ff_file) != NULL) { 1535 /* 1536 * Must use fd_close() here if there is 1537 * a reference from kqueue or we might have posix 1538 * advisory locks. 1539 */ 1540 if (__predict_true(ff->ff_refcnt == 0) && 1541 (noadvlock || fp->f_type != DTYPE_VNODE)) { 1542 ff->ff_file = NULL; 1543 ff->ff_exclose = false; 1544 ff->ff_allocated = false; 1545 closef(fp); 1546 } else { 1547 ff->ff_refcnt++; 1548 fd_close(fd); 1549 } 1550 } 1551 KASSERT(ff->ff_refcnt == 0); 1552 KASSERT(ff->ff_file == NULL); 1553 KASSERT(!ff->ff_exclose); 1554 KASSERT(!ff->ff_allocated); 1555 if (fd >= NDFDFILE) { 1556 pool_cache_put(fdfile_cache, ff); 1557 dt->dt_ff[fd] = NULL; 1558 } 1559 } 1560 1561 /* 1562 * Clean out the descriptor table for the next user and return 1563 * to the cache. 1564 */ 1565 if (__predict_false(dt != &fdp->fd_dtbuiltin)) { 1566 fd_dtab_free(fdp->fd_dt); 1567 /* Otherwise, done above. */ 1568 memset(&fdp->fd_dtbuiltin.dt_ff[NDFDFILE], 0, 1569 (NDFILE - NDFDFILE) * sizeof(fdp->fd_dtbuiltin.dt_ff[0])); 1570 fdp->fd_dt = &fdp->fd_dtbuiltin; 1571 } 1572 if (__predict_false(NDHISLOTS(nf) > NDHISLOTS(NDFILE))) { 1573 KASSERT(fdp->fd_himap != fdp->fd_dhimap); 1574 KASSERT(fdp->fd_lomap != fdp->fd_dlomap); 1575 fd_map_free(nf, fdp->fd_lomap, fdp->fd_himap); 1576 } 1577 if (__predict_false(fdp->fd_knhash != NULL)) { 1578 hashdone(fdp->fd_knhash, HASH_LIST, fdp->fd_knhashmask); 1579 fdp->fd_knhash = NULL; 1580 fdp->fd_knhashmask = 0; 1581 } else { 1582 KASSERT(fdp->fd_knhashmask == 0); 1583 } 1584 fdp->fd_dt = &fdp->fd_dtbuiltin; 1585 fdp->fd_lastkqfile = -1; 1586 fdp->fd_lastfile = -1; 1587 fdp->fd_freefile = 0; 1588 fdp->fd_exclose = false; 1589 memset(&fdp->fd_startzero, 0, sizeof(*fdp) - 1590 offsetof(filedesc_t, fd_startzero)); 1591 fdp->fd_himap = fdp->fd_dhimap; 1592 fdp->fd_lomap = fdp->fd_dlomap; 1593 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1594 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL); 1595 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin); 1596 #ifdef DEBUG 1597 fdp->fd_refcnt = 0; /* see fd_checkmaps */ 1598 #endif 1599 fd_checkmaps(fdp); 1600 pool_cache_put(filedesc_cache, fdp); 1601 } 1602 1603 /* 1604 * File Descriptor pseudo-device driver (/dev/fd/). 1605 * 1606 * Opening minor device N dup()s the file (if any) connected to file 1607 * descriptor N belonging to the calling process. Note that this driver 1608 * consists of only the ``open()'' routine, because all subsequent 1609 * references to this file will be direct to the other driver. 1610 */ 1611 static int 1612 filedescopen(dev_t dev, int mode, int type, lwp_t *l) 1613 { 1614 1615 /* 1616 * XXX Kludge: set dupfd to contain the value of the 1617 * the file descriptor being sought for duplication. The error 1618 * return ensures that the vnode for this device will be released 1619 * by vn_open. Open will detect this special error and take the 1620 * actions in fd_dupopen below. Other callers of vn_open or VOP_OPEN 1621 * will simply report the error. 1622 */ 1623 l->l_dupfd = minor(dev); /* XXX */ 1624 return EDUPFD; 1625 } 1626 1627 /* 1628 * Duplicate the specified descriptor to a free descriptor. 1629 */ 1630 int 1631 fd_dupopen(int old, int *new, int mode, int error) 1632 { 1633 filedesc_t *fdp; 1634 fdfile_t *ff; 1635 file_t *fp; 1636 fdtab_t *dt; 1637 1638 if ((fp = fd_getfile(old)) == NULL) { 1639 return EBADF; 1640 } 1641 fdp = curlwp->l_fd; 1642 dt = fdp->fd_dt; 1643 ff = dt->dt_ff[old]; 1644 1645 /* 1646 * There are two cases of interest here. 1647 * 1648 * For EDUPFD simply dup (old) to file descriptor 1649 * (new) and return. 1650 * 1651 * For EMOVEFD steal away the file structure from (old) and 1652 * store it in (new). (old) is effectively closed by 1653 * this operation. 1654 * 1655 * Any other error code is just returned. 1656 */ 1657 switch (error) { 1658 case EDUPFD: 1659 /* 1660 * Check that the mode the file is being opened for is a 1661 * subset of the mode of the existing descriptor. 1662 */ 1663 if (((mode & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) { 1664 error = EACCES; 1665 break; 1666 } 1667 1668 /* Copy it. */ 1669 error = fd_dup(fp, 0, new, ff->ff_exclose); 1670 break; 1671 1672 case EMOVEFD: 1673 /* Copy it. */ 1674 error = fd_dup(fp, 0, new, ff->ff_exclose); 1675 if (error != 0) { 1676 break; 1677 } 1678 1679 /* Steal away the file pointer from 'old'. */ 1680 (void)fd_close(old); 1681 return 0; 1682 } 1683 1684 fd_putfile(old); 1685 return error; 1686 } 1687 1688 /* 1689 * Close open files on exec. 1690 */ 1691 void 1692 fd_closeexec(void) 1693 { 1694 proc_t *p; 1695 filedesc_t *fdp; 1696 fdfile_t *ff; 1697 lwp_t *l; 1698 fdtab_t *dt; 1699 int fd; 1700 1701 l = curlwp; 1702 p = l->l_proc; 1703 fdp = p->p_fd; 1704 1705 if (fdp->fd_refcnt > 1) { 1706 fdp = fd_copy(); 1707 fd_free(); 1708 p->p_fd = fdp; 1709 l->l_fd = fdp; 1710 } 1711 if (!fdp->fd_exclose) { 1712 return; 1713 } 1714 fdp->fd_exclose = false; 1715 dt = fdp->fd_dt; 1716 1717 for (fd = 0; fd <= fdp->fd_lastfile; fd++) { 1718 if ((ff = dt->dt_ff[fd]) == NULL) { 1719 KASSERT(fd >= NDFDFILE); 1720 continue; 1721 } 1722 KASSERT(fd >= NDFDFILE || 1723 ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1724 if (ff->ff_file == NULL) 1725 continue; 1726 if (ff->ff_exclose) { 1727 /* 1728 * We need a reference to close the file. 1729 * No other threads can see the fdfile_t at 1730 * this point, so don't bother locking. 1731 */ 1732 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); 1733 ff->ff_refcnt++; 1734 fd_close(fd); 1735 } 1736 } 1737 } 1738 1739 /* 1740 * Sets descriptor owner. If the owner is a process, 'pgid' 1741 * is set to positive value, process ID. If the owner is process group, 1742 * 'pgid' is set to -pg_id. 1743 */ 1744 int 1745 fsetown(pid_t *pgid, u_long cmd, const void *data) 1746 { 1747 pid_t id = *(const pid_t *)data; 1748 int error; 1749 1750 switch (cmd) { 1751 case TIOCSPGRP: 1752 if (id < 0) 1753 return EINVAL; 1754 id = -id; 1755 break; 1756 default: 1757 break; 1758 } 1759 if (id > 0) { 1760 mutex_enter(proc_lock); 1761 error = proc_find(id) ? 0 : ESRCH; 1762 mutex_exit(proc_lock); 1763 } else if (id < 0) { 1764 error = pgid_in_session(curproc, -id); 1765 } else { 1766 error = 0; 1767 } 1768 if (!error) { 1769 *pgid = id; 1770 } 1771 return error; 1772 } 1773 1774 void 1775 fd_set_exclose(struct lwp *l, int fd, bool exclose) 1776 { 1777 filedesc_t *fdp = l->l_fd; 1778 fdfile_t *ff = fdp->fd_dt->dt_ff[fd]; 1779 1780 ff->ff_exclose = exclose; 1781 if (exclose) 1782 fdp->fd_exclose = true; 1783 } 1784 1785 /* 1786 * Return descriptor owner information. If the value is positive, 1787 * it's process ID. If it's negative, it's process group ID and 1788 * needs the sign removed before use. 1789 */ 1790 int 1791 fgetown(pid_t pgid, u_long cmd, void *data) 1792 { 1793 1794 switch (cmd) { 1795 case TIOCGPGRP: 1796 *(int *)data = -pgid; 1797 break; 1798 default: 1799 *(int *)data = pgid; 1800 break; 1801 } 1802 return 0; 1803 } 1804 1805 /* 1806 * Send signal to descriptor owner, either process or process group. 1807 */ 1808 void 1809 fownsignal(pid_t pgid, int signo, int code, int band, void *fdescdata) 1810 { 1811 ksiginfo_t ksi; 1812 1813 KASSERT(!cpu_intr_p()); 1814 1815 if (pgid == 0) { 1816 return; 1817 } 1818 1819 KSI_INIT(&ksi); 1820 ksi.ksi_signo = signo; 1821 ksi.ksi_code = code; 1822 ksi.ksi_band = band; 1823 1824 mutex_enter(proc_lock); 1825 if (pgid > 0) { 1826 struct proc *p1; 1827 1828 p1 = proc_find(pgid); 1829 if (p1 != NULL) { 1830 kpsignal(p1, &ksi, fdescdata); 1831 } 1832 } else { 1833 struct pgrp *pgrp; 1834 1835 KASSERT(pgid < 0); 1836 pgrp = pgrp_find(-pgid); 1837 if (pgrp != NULL) { 1838 kpgsignal(pgrp, &ksi, fdescdata, 0); 1839 } 1840 } 1841 mutex_exit(proc_lock); 1842 } 1843 1844 int 1845 fd_clone(file_t *fp, unsigned fd, int flag, const struct fileops *fops, 1846 void *data) 1847 { 1848 1849 fp->f_flag = flag; 1850 fp->f_type = DTYPE_MISC; 1851 fp->f_ops = fops; 1852 fp->f_data = data; 1853 curlwp->l_dupfd = fd; 1854 fd_affix(curproc, fp, fd); 1855 1856 return EMOVEFD; 1857 } 1858 1859 int 1860 fnullop_fcntl(file_t *fp, u_int cmd, void *data) 1861 { 1862 1863 if (cmd == F_SETFL) 1864 return 0; 1865 1866 return EOPNOTSUPP; 1867 } 1868 1869 int 1870 fnullop_poll(file_t *fp, int which) 1871 { 1872 1873 return 0; 1874 } 1875 1876 int 1877 fnullop_kqfilter(file_t *fp, struct knote *kn) 1878 { 1879 1880 return 0; 1881 } 1882 1883 void 1884 fnullop_restart(file_t *fp) 1885 { 1886 1887 } 1888 1889 int 1890 fbadop_read(file_t *fp, off_t *offset, struct uio *uio, 1891 kauth_cred_t cred, int flags) 1892 { 1893 1894 return EOPNOTSUPP; 1895 } 1896 1897 int 1898 fbadop_write(file_t *fp, off_t *offset, struct uio *uio, 1899 kauth_cred_t cred, int flags) 1900 { 1901 1902 return EOPNOTSUPP; 1903 } 1904 1905 int 1906 fbadop_ioctl(file_t *fp, u_long com, void *data) 1907 { 1908 1909 return EOPNOTSUPP; 1910 } 1911 1912 int 1913 fbadop_stat(file_t *fp, struct stat *sb) 1914 { 1915 1916 return EOPNOTSUPP; 1917 } 1918 1919 int 1920 fbadop_close(file_t *fp) 1921 { 1922 1923 return EOPNOTSUPP; 1924 } 1925 1926 /* 1927 * sysctl routines pertaining to file descriptors 1928 */ 1929 1930 /* Initialized in sysctl_init() for now... */ 1931 extern kmutex_t sysctl_file_marker_lock; 1932 static u_int sysctl_file_marker = 1; 1933 1934 /* 1935 * Expects to be called with proc_lock and sysctl_file_marker_lock locked. 1936 */ 1937 static void 1938 sysctl_file_marker_reset(void) 1939 { 1940 struct proc *p; 1941 1942 PROCLIST_FOREACH(p, &allproc) { 1943 struct filedesc *fd = p->p_fd; 1944 fdtab_t *dt; 1945 u_int i; 1946 1947 mutex_enter(&fd->fd_lock); 1948 dt = fd->fd_dt; 1949 for (i = 0; i < dt->dt_nfiles; i++) { 1950 struct file *fp; 1951 fdfile_t *ff; 1952 1953 if ((ff = dt->dt_ff[i]) == NULL) { 1954 continue; 1955 } 1956 if ((fp = ff->ff_file) == NULL) { 1957 continue; 1958 } 1959 fp->f_marker = 0; 1960 } 1961 mutex_exit(&fd->fd_lock); 1962 } 1963 } 1964 1965 /* 1966 * sysctl helper routine for kern.file pseudo-subtree. 1967 */ 1968 static int 1969 sysctl_kern_file(SYSCTLFN_ARGS) 1970 { 1971 int error; 1972 size_t buflen; 1973 struct file *fp, fbuf; 1974 char *start, *where; 1975 struct proc *p; 1976 1977 start = where = oldp; 1978 buflen = *oldlenp; 1979 1980 if (where == NULL) { 1981 /* 1982 * overestimate by 10 files 1983 */ 1984 *oldlenp = sizeof(filehead) + (nfiles + 10) * 1985 sizeof(struct file); 1986 return 0; 1987 } 1988 1989 /* 1990 * first sysctl_copyout filehead 1991 */ 1992 if (buflen < sizeof(filehead)) { 1993 *oldlenp = 0; 1994 return 0; 1995 } 1996 sysctl_unlock(); 1997 error = sysctl_copyout(l, &filehead, where, sizeof(filehead)); 1998 if (error) { 1999 sysctl_relock(); 2000 return error; 2001 } 2002 buflen -= sizeof(filehead); 2003 where += sizeof(filehead); 2004 2005 /* 2006 * followed by an array of file structures 2007 */ 2008 mutex_enter(&sysctl_file_marker_lock); 2009 mutex_enter(proc_lock); 2010 PROCLIST_FOREACH(p, &allproc) { 2011 struct filedesc *fd; 2012 fdtab_t *dt; 2013 u_int i; 2014 2015 if (p->p_stat == SIDL) { 2016 /* skip embryonic processes */ 2017 continue; 2018 } 2019 mutex_enter(p->p_lock); 2020 error = kauth_authorize_process(l->l_cred, 2021 KAUTH_PROCESS_CANSEE, p, 2022 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES), 2023 NULL, NULL); 2024 mutex_exit(p->p_lock); 2025 if (error != 0) { 2026 /* 2027 * Don't leak kauth retval if we're silently 2028 * skipping this entry. 2029 */ 2030 error = 0; 2031 continue; 2032 } 2033 2034 /* 2035 * Grab a hold on the process. 2036 */ 2037 if (!rw_tryenter(&p->p_reflock, RW_READER)) { 2038 continue; 2039 } 2040 mutex_exit(proc_lock); 2041 2042 fd = p->p_fd; 2043 mutex_enter(&fd->fd_lock); 2044 dt = fd->fd_dt; 2045 for (i = 0; i < dt->dt_nfiles; i++) { 2046 fdfile_t *ff; 2047 2048 if ((ff = dt->dt_ff[i]) == NULL) { 2049 continue; 2050 } 2051 if ((fp = ff->ff_file) == NULL) { 2052 continue; 2053 } 2054 2055 mutex_enter(&fp->f_lock); 2056 2057 if ((fp->f_count == 0) || 2058 (fp->f_marker == sysctl_file_marker)) { 2059 mutex_exit(&fp->f_lock); 2060 continue; 2061 } 2062 2063 /* Check that we have enough space. */ 2064 if (buflen < sizeof(struct file)) { 2065 *oldlenp = where - start; 2066 mutex_exit(&fp->f_lock); 2067 error = ENOMEM; 2068 break; 2069 } 2070 2071 memcpy(&fbuf, fp, sizeof(fbuf)); 2072 mutex_exit(&fp->f_lock); 2073 error = sysctl_copyout(l, &fbuf, where, sizeof(fbuf)); 2074 if (error) { 2075 break; 2076 } 2077 buflen -= sizeof(struct file); 2078 where += sizeof(struct file); 2079 2080 fp->f_marker = sysctl_file_marker; 2081 } 2082 mutex_exit(&fd->fd_lock); 2083 2084 /* 2085 * Release reference to process. 2086 */ 2087 mutex_enter(proc_lock); 2088 rw_exit(&p->p_reflock); 2089 2090 if (error) 2091 break; 2092 } 2093 2094 sysctl_file_marker++; 2095 /* Reset all markers if wrapped. */ 2096 if (sysctl_file_marker == 0) { 2097 sysctl_file_marker_reset(); 2098 sysctl_file_marker++; 2099 } 2100 2101 mutex_exit(proc_lock); 2102 mutex_exit(&sysctl_file_marker_lock); 2103 2104 *oldlenp = where - start; 2105 sysctl_relock(); 2106 return error; 2107 } 2108 2109 /* 2110 * sysctl helper function for kern.file2 2111 */ 2112 static int 2113 sysctl_kern_file2(SYSCTLFN_ARGS) 2114 { 2115 struct proc *p; 2116 struct file *fp; 2117 struct filedesc *fd; 2118 struct kinfo_file kf; 2119 char *dp; 2120 u_int i, op; 2121 size_t len, needed, elem_size, out_size; 2122 int error, arg, elem_count; 2123 fdfile_t *ff; 2124 fdtab_t *dt; 2125 2126 if (namelen == 1 && name[0] == CTL_QUERY) 2127 return sysctl_query(SYSCTLFN_CALL(rnode)); 2128 2129 if (namelen != 4) 2130 return EINVAL; 2131 2132 error = 0; 2133 dp = oldp; 2134 len = (oldp != NULL) ? *oldlenp : 0; 2135 op = name[0]; 2136 arg = name[1]; 2137 elem_size = name[2]; 2138 elem_count = name[3]; 2139 out_size = MIN(sizeof(kf), elem_size); 2140 needed = 0; 2141 2142 if (elem_size < 1 || elem_count < 0) 2143 return EINVAL; 2144 2145 switch (op) { 2146 case KERN_FILE_BYFILE: 2147 case KERN_FILE_BYPID: 2148 /* 2149 * We're traversing the process list in both cases; the BYFILE 2150 * case does additional work of keeping track of files already 2151 * looked at. 2152 */ 2153 2154 /* doesn't use arg so it must be zero */ 2155 if ((op == KERN_FILE_BYFILE) && (arg != 0)) 2156 return EINVAL; 2157 2158 if ((op == KERN_FILE_BYPID) && (arg < -1)) 2159 /* -1 means all processes */ 2160 return EINVAL; 2161 2162 sysctl_unlock(); 2163 if (op == KERN_FILE_BYFILE) 2164 mutex_enter(&sysctl_file_marker_lock); 2165 mutex_enter(proc_lock); 2166 PROCLIST_FOREACH(p, &allproc) { 2167 if (p->p_stat == SIDL) { 2168 /* skip embryonic processes */ 2169 continue; 2170 } 2171 if (arg > 0 && p->p_pid != arg) { 2172 /* pick only the one we want */ 2173 /* XXX want 0 to mean "kernel files" */ 2174 continue; 2175 } 2176 mutex_enter(p->p_lock); 2177 error = kauth_authorize_process(l->l_cred, 2178 KAUTH_PROCESS_CANSEE, p, 2179 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES), 2180 NULL, NULL); 2181 mutex_exit(p->p_lock); 2182 if (error != 0) { 2183 /* 2184 * Don't leak kauth retval if we're silently 2185 * skipping this entry. 2186 */ 2187 error = 0; 2188 continue; 2189 } 2190 2191 /* 2192 * Grab a hold on the process. 2193 */ 2194 if (!rw_tryenter(&p->p_reflock, RW_READER)) { 2195 continue; 2196 } 2197 mutex_exit(proc_lock); 2198 2199 fd = p->p_fd; 2200 mutex_enter(&fd->fd_lock); 2201 dt = fd->fd_dt; 2202 for (i = 0; i < dt->dt_nfiles; i++) { 2203 if ((ff = dt->dt_ff[i]) == NULL) { 2204 continue; 2205 } 2206 if ((fp = ff->ff_file) == NULL) { 2207 continue; 2208 } 2209 2210 if ((op == KERN_FILE_BYFILE) && 2211 (fp->f_marker == sysctl_file_marker)) { 2212 continue; 2213 } 2214 if (len >= elem_size && elem_count > 0) { 2215 mutex_enter(&fp->f_lock); 2216 fill_file(&kf, fp, ff, i, p->p_pid); 2217 mutex_exit(&fp->f_lock); 2218 mutex_exit(&fd->fd_lock); 2219 error = sysctl_copyout(l, 2220 &kf, dp, out_size); 2221 mutex_enter(&fd->fd_lock); 2222 if (error) 2223 break; 2224 dp += elem_size; 2225 len -= elem_size; 2226 } 2227 if (op == KERN_FILE_BYFILE) 2228 fp->f_marker = sysctl_file_marker; 2229 needed += elem_size; 2230 if (elem_count > 0 && elem_count != INT_MAX) 2231 elem_count--; 2232 } 2233 mutex_exit(&fd->fd_lock); 2234 2235 /* 2236 * Release reference to process. 2237 */ 2238 mutex_enter(proc_lock); 2239 rw_exit(&p->p_reflock); 2240 } 2241 if (op == KERN_FILE_BYFILE) { 2242 sysctl_file_marker++; 2243 2244 /* Reset all markers if wrapped. */ 2245 if (sysctl_file_marker == 0) { 2246 sysctl_file_marker_reset(); 2247 sysctl_file_marker++; 2248 } 2249 } 2250 mutex_exit(proc_lock); 2251 if (op == KERN_FILE_BYFILE) 2252 mutex_exit(&sysctl_file_marker_lock); 2253 sysctl_relock(); 2254 break; 2255 default: 2256 return EINVAL; 2257 } 2258 2259 if (oldp == NULL) 2260 needed += KERN_FILESLOP * elem_size; 2261 *oldlenp = needed; 2262 2263 return error; 2264 } 2265 2266 static void 2267 fill_file(struct kinfo_file *kp, const file_t *fp, const fdfile_t *ff, 2268 int i, pid_t pid) 2269 { 2270 2271 memset(kp, 0, sizeof(*kp)); 2272 2273 kp->ki_fileaddr = PTRTOUINT64(fp); 2274 kp->ki_flag = fp->f_flag; 2275 kp->ki_iflags = 0; 2276 kp->ki_ftype = fp->f_type; 2277 kp->ki_count = fp->f_count; 2278 kp->ki_msgcount = fp->f_msgcount; 2279 kp->ki_fucred = PTRTOUINT64(fp->f_cred); 2280 kp->ki_fuid = kauth_cred_geteuid(fp->f_cred); 2281 kp->ki_fgid = kauth_cred_getegid(fp->f_cred); 2282 kp->ki_fops = PTRTOUINT64(fp->f_ops); 2283 kp->ki_foffset = fp->f_offset; 2284 kp->ki_fdata = PTRTOUINT64(fp->f_data); 2285 2286 /* vnode information to glue this file to something */ 2287 if (fp->f_type == DTYPE_VNODE) { 2288 struct vnode *vp = (struct vnode *)fp->f_data; 2289 2290 kp->ki_vun = PTRTOUINT64(vp->v_un.vu_socket); 2291 kp->ki_vsize = vp->v_size; 2292 kp->ki_vtype = vp->v_type; 2293 kp->ki_vtag = vp->v_tag; 2294 kp->ki_vdata = PTRTOUINT64(vp->v_data); 2295 } 2296 2297 /* process information when retrieved via KERN_FILE_BYPID */ 2298 if (ff != NULL) { 2299 kp->ki_pid = pid; 2300 kp->ki_fd = i; 2301 kp->ki_ofileflags = ff->ff_exclose; 2302 kp->ki_usecount = ff->ff_refcnt; 2303 } 2304 } 2305