1 /* $NetBSD: kern_descrip.c,v 1.224 2014/03/16 05:20:30 dholland 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 1.224 2014/03/16 05:20:30 dholland 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_flag = D_OTHER | D_MPSAFE 136 }; 137 138 /* For ease of reading. */ 139 __strong_alias(fd_putvnode,fd_putfile) 140 __strong_alias(fd_putsock,fd_putfile) 141 142 /* 143 * Initialize the descriptor system. 144 */ 145 void 146 fd_sys_init(void) 147 { 148 static struct sysctllog *clog; 149 150 mutex_init(&filelist_lock, MUTEX_DEFAULT, IPL_NONE); 151 152 file_cache = pool_cache_init(sizeof(file_t), coherency_unit, 0, 153 0, "file", NULL, IPL_NONE, file_ctor, file_dtor, NULL); 154 KASSERT(file_cache != NULL); 155 156 fdfile_cache = pool_cache_init(sizeof(fdfile_t), coherency_unit, 0, 157 PR_LARGECACHE, "fdfile", NULL, IPL_NONE, fdfile_ctor, fdfile_dtor, 158 NULL); 159 KASSERT(fdfile_cache != NULL); 160 161 filedesc_cache = pool_cache_init(sizeof(filedesc_t), coherency_unit, 162 0, 0, "filedesc", NULL, IPL_NONE, filedesc_ctor, filedesc_dtor, 163 NULL); 164 KASSERT(filedesc_cache != NULL); 165 166 sysctl_createv(&clog, 0, NULL, NULL, 167 CTLFLAG_PERMANENT, 168 CTLTYPE_STRUCT, "file", 169 SYSCTL_DESCR("System open file table"), 170 sysctl_kern_file, 0, NULL, 0, 171 CTL_KERN, KERN_FILE, CTL_EOL); 172 sysctl_createv(&clog, 0, NULL, NULL, 173 CTLFLAG_PERMANENT, 174 CTLTYPE_STRUCT, "file2", 175 SYSCTL_DESCR("System open file table"), 176 sysctl_kern_file2, 0, NULL, 0, 177 CTL_KERN, KERN_FILE2, CTL_EOL); 178 } 179 180 static bool 181 fd_isused(filedesc_t *fdp, unsigned fd) 182 { 183 u_int off = fd >> NDENTRYSHIFT; 184 185 KASSERT(fd < fdp->fd_dt->dt_nfiles); 186 187 return (fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) != 0; 188 } 189 190 /* 191 * Verify that the bitmaps match the descriptor table. 192 */ 193 static inline void 194 fd_checkmaps(filedesc_t *fdp) 195 { 196 #ifdef DEBUG 197 fdtab_t *dt; 198 u_int fd; 199 200 dt = fdp->fd_dt; 201 if (fdp->fd_refcnt == -1) { 202 /* 203 * fd_free tears down the table without maintaining its bitmap. 204 */ 205 return; 206 } 207 for (fd = 0; fd < dt->dt_nfiles; fd++) { 208 if (fd < NDFDFILE) { 209 KASSERT(dt->dt_ff[fd] == 210 (fdfile_t *)fdp->fd_dfdfile[fd]); 211 } 212 if (dt->dt_ff[fd] == NULL) { 213 KASSERT(!fd_isused(fdp, fd)); 214 } else if (dt->dt_ff[fd]->ff_file != NULL) { 215 KASSERT(fd_isused(fdp, fd)); 216 } 217 } 218 #endif 219 } 220 221 static int 222 fd_next_zero(filedesc_t *fdp, uint32_t *bitmap, int want, u_int bits) 223 { 224 int i, off, maxoff; 225 uint32_t sub; 226 227 KASSERT(mutex_owned(&fdp->fd_lock)); 228 229 fd_checkmaps(fdp); 230 231 if (want > bits) 232 return -1; 233 234 off = want >> NDENTRYSHIFT; 235 i = want & NDENTRYMASK; 236 if (i) { 237 sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i)); 238 if (sub != ~0) 239 goto found; 240 off++; 241 } 242 243 maxoff = NDLOSLOTS(bits); 244 while (off < maxoff) { 245 if ((sub = bitmap[off]) != ~0) 246 goto found; 247 off++; 248 } 249 250 return -1; 251 252 found: 253 return (off << NDENTRYSHIFT) + ffs(~sub) - 1; 254 } 255 256 static int 257 fd_last_set(filedesc_t *fd, int last) 258 { 259 int off, i; 260 fdfile_t **ff = fd->fd_dt->dt_ff; 261 uint32_t *bitmap = fd->fd_lomap; 262 263 KASSERT(mutex_owned(&fd->fd_lock)); 264 265 fd_checkmaps(fd); 266 267 off = (last - 1) >> NDENTRYSHIFT; 268 269 while (off >= 0 && !bitmap[off]) 270 off--; 271 272 if (off < 0) 273 return -1; 274 275 i = ((off + 1) << NDENTRYSHIFT) - 1; 276 if (i >= last) 277 i = last - 1; 278 279 /* XXX should use bitmap */ 280 while (i > 0 && (ff[i] == NULL || !ff[i]->ff_allocated)) 281 i--; 282 283 return i; 284 } 285 286 static inline void 287 fd_used(filedesc_t *fdp, unsigned fd) 288 { 289 u_int off = fd >> NDENTRYSHIFT; 290 fdfile_t *ff; 291 292 ff = fdp->fd_dt->dt_ff[fd]; 293 294 KASSERT(mutex_owned(&fdp->fd_lock)); 295 KASSERT((fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) == 0); 296 KASSERT(ff != NULL); 297 KASSERT(ff->ff_file == NULL); 298 KASSERT(!ff->ff_allocated); 299 300 ff->ff_allocated = true; 301 fdp->fd_lomap[off] |= 1 << (fd & NDENTRYMASK); 302 if (__predict_false(fdp->fd_lomap[off] == ~0)) { 303 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & 304 (1 << (off & NDENTRYMASK))) == 0); 305 fdp->fd_himap[off >> NDENTRYSHIFT] |= 1 << (off & NDENTRYMASK); 306 } 307 308 if ((int)fd > fdp->fd_lastfile) { 309 fdp->fd_lastfile = fd; 310 } 311 312 fd_checkmaps(fdp); 313 } 314 315 static inline void 316 fd_unused(filedesc_t *fdp, unsigned fd) 317 { 318 u_int off = fd >> NDENTRYSHIFT; 319 fdfile_t *ff; 320 321 ff = fdp->fd_dt->dt_ff[fd]; 322 323 /* 324 * Don't assert the lock is held here, as we may be copying 325 * the table during exec() and it is not needed there. 326 * procfs and sysctl are locked out by proc::p_reflock. 327 * 328 * KASSERT(mutex_owned(&fdp->fd_lock)); 329 */ 330 KASSERT(ff != NULL); 331 KASSERT(ff->ff_file == NULL); 332 KASSERT(ff->ff_allocated); 333 334 if (fd < fdp->fd_freefile) { 335 fdp->fd_freefile = fd; 336 } 337 338 if (fdp->fd_lomap[off] == ~0) { 339 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & 340 (1 << (off & NDENTRYMASK))) != 0); 341 fdp->fd_himap[off >> NDENTRYSHIFT] &= 342 ~(1 << (off & NDENTRYMASK)); 343 } 344 KASSERT((fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) != 0); 345 fdp->fd_lomap[off] &= ~(1 << (fd & NDENTRYMASK)); 346 ff->ff_allocated = false; 347 348 KASSERT(fd <= fdp->fd_lastfile); 349 if (fd == fdp->fd_lastfile) { 350 fdp->fd_lastfile = fd_last_set(fdp, fd); 351 } 352 fd_checkmaps(fdp); 353 } 354 355 /* 356 * Look up the file structure corresponding to a file descriptor 357 * and return the file, holding a reference on the descriptor. 358 */ 359 file_t * 360 fd_getfile(unsigned fd) 361 { 362 filedesc_t *fdp; 363 fdfile_t *ff; 364 file_t *fp; 365 fdtab_t *dt; 366 367 /* 368 * Look up the fdfile structure representing this descriptor. 369 * We are doing this unlocked. See fd_tryexpand(). 370 */ 371 fdp = curlwp->l_fd; 372 dt = fdp->fd_dt; 373 if (__predict_false(fd >= dt->dt_nfiles)) { 374 return NULL; 375 } 376 ff = dt->dt_ff[fd]; 377 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 378 if (__predict_false(ff == NULL)) { 379 return NULL; 380 } 381 382 /* Now get a reference to the descriptor. */ 383 if (fdp->fd_refcnt == 1) { 384 /* 385 * Single threaded: don't need to worry about concurrent 386 * access (other than earlier calls to kqueue, which may 387 * hold a reference to the descriptor). 388 */ 389 ff->ff_refcnt++; 390 } else { 391 /* 392 * Multi threaded: issue a memory barrier to ensure that we 393 * acquire the file pointer _after_ adding a reference. If 394 * no memory barrier, we could fetch a stale pointer. 395 */ 396 atomic_inc_uint(&ff->ff_refcnt); 397 #ifndef __HAVE_ATOMIC_AS_MEMBAR 398 membar_enter(); 399 #endif 400 } 401 402 /* 403 * If the file is not open or is being closed then put the 404 * reference back. 405 */ 406 fp = ff->ff_file; 407 if (__predict_true(fp != NULL)) { 408 return fp; 409 } 410 fd_putfile(fd); 411 return NULL; 412 } 413 414 /* 415 * Release a reference to a file descriptor acquired with fd_getfile(). 416 */ 417 void 418 fd_putfile(unsigned fd) 419 { 420 filedesc_t *fdp; 421 fdfile_t *ff; 422 u_int u, v; 423 424 fdp = curlwp->l_fd; 425 ff = fdp->fd_dt->dt_ff[fd]; 426 427 KASSERT(fd < fdp->fd_dt->dt_nfiles); 428 KASSERT(ff != NULL); 429 KASSERT((ff->ff_refcnt & FR_MASK) > 0); 430 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 431 432 if (fdp->fd_refcnt == 1) { 433 /* 434 * Single threaded: don't need to worry about concurrent 435 * access (other than earlier calls to kqueue, which may 436 * hold a reference to the descriptor). 437 */ 438 if (__predict_false((ff->ff_refcnt & FR_CLOSING) != 0)) { 439 fd_close(fd); 440 return; 441 } 442 ff->ff_refcnt--; 443 return; 444 } 445 446 /* 447 * Ensure that any use of the file is complete and globally 448 * visible before dropping the final reference. If no membar, 449 * the current CPU could still access memory associated with 450 * the file after it has been freed or recycled by another 451 * CPU. 452 */ 453 #ifndef __HAVE_ATOMIC_AS_MEMBAR 454 membar_exit(); 455 #endif 456 457 /* 458 * Be optimistic and start out with the assumption that no other 459 * threads are trying to close the descriptor. If the CAS fails, 460 * we lost a race and/or it's being closed. 461 */ 462 for (u = ff->ff_refcnt & FR_MASK;; u = v) { 463 v = atomic_cas_uint(&ff->ff_refcnt, u, u - 1); 464 if (__predict_true(u == v)) { 465 return; 466 } 467 if (__predict_false((v & FR_CLOSING) != 0)) { 468 break; 469 } 470 } 471 472 /* Another thread is waiting to close the file: join it. */ 473 (void)fd_close(fd); 474 } 475 476 /* 477 * Convenience wrapper around fd_getfile() that returns reference 478 * to a vnode. 479 */ 480 int 481 fd_getvnode(unsigned fd, file_t **fpp) 482 { 483 vnode_t *vp; 484 file_t *fp; 485 486 fp = fd_getfile(fd); 487 if (__predict_false(fp == NULL)) { 488 return EBADF; 489 } 490 if (__predict_false(fp->f_type != DTYPE_VNODE)) { 491 fd_putfile(fd); 492 return EINVAL; 493 } 494 vp = fp->f_data; 495 if (__predict_false(vp->v_type == VBAD)) { 496 /* XXX Is this case really necessary? */ 497 fd_putfile(fd); 498 return EBADF; 499 } 500 *fpp = fp; 501 return 0; 502 } 503 504 /* 505 * Convenience wrapper around fd_getfile() that returns reference 506 * to a socket. 507 */ 508 int 509 fd_getsock1(unsigned fd, struct socket **sop, file_t **fp) 510 { 511 *fp = fd_getfile(fd); 512 if (__predict_false(*fp == NULL)) { 513 return EBADF; 514 } 515 if (__predict_false((*fp)->f_type != DTYPE_SOCKET)) { 516 fd_putfile(fd); 517 return ENOTSOCK; 518 } 519 *sop = (*fp)->f_data; 520 return 0; 521 } 522 523 int 524 fd_getsock(unsigned fd, struct socket **sop) 525 { 526 file_t *fp; 527 return fd_getsock1(fd, sop, &fp); 528 } 529 530 /* 531 * Look up the file structure corresponding to a file descriptor 532 * and return it with a reference held on the file, not the 533 * descriptor. 534 * 535 * This is heavyweight and only used when accessing descriptors 536 * from a foreign process. The caller must ensure that `p' does 537 * not exit or fork across this call. 538 * 539 * To release the file (not descriptor) reference, use closef(). 540 */ 541 file_t * 542 fd_getfile2(proc_t *p, unsigned fd) 543 { 544 filedesc_t *fdp; 545 fdfile_t *ff; 546 file_t *fp; 547 fdtab_t *dt; 548 549 fdp = p->p_fd; 550 mutex_enter(&fdp->fd_lock); 551 dt = fdp->fd_dt; 552 if (fd >= dt->dt_nfiles) { 553 mutex_exit(&fdp->fd_lock); 554 return NULL; 555 } 556 if ((ff = dt->dt_ff[fd]) == NULL) { 557 mutex_exit(&fdp->fd_lock); 558 return NULL; 559 } 560 if ((fp = ff->ff_file) == NULL) { 561 mutex_exit(&fdp->fd_lock); 562 return NULL; 563 } 564 mutex_enter(&fp->f_lock); 565 fp->f_count++; 566 mutex_exit(&fp->f_lock); 567 mutex_exit(&fdp->fd_lock); 568 569 return fp; 570 } 571 572 /* 573 * Internal form of close. Must be called with a reference to the 574 * descriptor, and will drop the reference. When all descriptor 575 * references are dropped, releases the descriptor slot and a single 576 * reference to the file structure. 577 */ 578 int 579 fd_close(unsigned fd) 580 { 581 struct flock lf; 582 filedesc_t *fdp; 583 fdfile_t *ff; 584 file_t *fp; 585 proc_t *p; 586 lwp_t *l; 587 u_int refcnt; 588 589 l = curlwp; 590 p = l->l_proc; 591 fdp = l->l_fd; 592 ff = fdp->fd_dt->dt_ff[fd]; 593 594 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 595 596 mutex_enter(&fdp->fd_lock); 597 KASSERT((ff->ff_refcnt & FR_MASK) > 0); 598 if (__predict_false(ff->ff_file == NULL)) { 599 /* 600 * Another user of the file is already closing, and is 601 * waiting for other users of the file to drain. Release 602 * our reference, and wake up the closer. 603 */ 604 atomic_dec_uint(&ff->ff_refcnt); 605 cv_broadcast(&ff->ff_closing); 606 mutex_exit(&fdp->fd_lock); 607 608 /* 609 * An application error, so pretend that the descriptor 610 * was already closed. We can't safely wait for it to 611 * be closed without potentially deadlocking. 612 */ 613 return (EBADF); 614 } 615 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); 616 617 /* 618 * There may be multiple users of this file within the process. 619 * Notify existing and new users that the file is closing. This 620 * will prevent them from adding additional uses to this file 621 * while we are closing it. 622 */ 623 fp = ff->ff_file; 624 ff->ff_file = NULL; 625 ff->ff_exclose = false; 626 627 /* 628 * We expect the caller to hold a descriptor reference - drop it. 629 * The reference count may increase beyond zero at this point due 630 * to an erroneous descriptor reference by an application, but 631 * fd_getfile() will notice that the file is being closed and drop 632 * the reference again. 633 */ 634 if (fdp->fd_refcnt == 1) { 635 /* Single threaded. */ 636 refcnt = --(ff->ff_refcnt); 637 } else { 638 /* Multi threaded. */ 639 #ifndef __HAVE_ATOMIC_AS_MEMBAR 640 membar_producer(); 641 #endif 642 refcnt = atomic_dec_uint_nv(&ff->ff_refcnt); 643 } 644 if (__predict_false(refcnt != 0)) { 645 /* 646 * Wait for other references to drain. This is typically 647 * an application error - the descriptor is being closed 648 * while still in use. 649 * (Or just a threaded application trying to unblock its 650 * thread that sleeps in (say) accept()). 651 */ 652 atomic_or_uint(&ff->ff_refcnt, FR_CLOSING); 653 654 /* 655 * Remove any knotes attached to the file. A knote 656 * attached to the descriptor can hold references on it. 657 */ 658 mutex_exit(&fdp->fd_lock); 659 if (!SLIST_EMPTY(&ff->ff_knlist)) { 660 knote_fdclose(fd); 661 } 662 663 /* 664 * Since the file system code doesn't know which fd 665 * each request came from (think dup()), we have to 666 * ask it to return ERESTART for any long-term blocks. 667 * The re-entry through read/write/etc will detect the 668 * closed fd and return EBAFD. 669 * Blocked partial writes may return a short length. 670 */ 671 (*fp->f_ops->fo_restart)(fp); 672 mutex_enter(&fdp->fd_lock); 673 674 /* 675 * We need to see the count drop to zero at least once, 676 * in order to ensure that all pre-existing references 677 * have been drained. New references past this point are 678 * of no interest. 679 * XXX (dsl) this may need to call fo_restart() after a 680 * timeout to guarantee that all the system calls exit. 681 */ 682 while ((ff->ff_refcnt & FR_MASK) != 0) { 683 cv_wait(&ff->ff_closing, &fdp->fd_lock); 684 } 685 atomic_and_uint(&ff->ff_refcnt, ~FR_CLOSING); 686 } else { 687 /* If no references, there must be no knotes. */ 688 KASSERT(SLIST_EMPTY(&ff->ff_knlist)); 689 } 690 691 /* 692 * POSIX record locking dictates that any close releases ALL 693 * locks owned by this process. This is handled by setting 694 * a flag in the unlock to free ONLY locks obeying POSIX 695 * semantics, and not to free BSD-style file locks. 696 * If the descriptor was in a message, POSIX-style locks 697 * aren't passed with the descriptor. 698 */ 699 if (__predict_false((p->p_flag & PK_ADVLOCK) != 0 && 700 fp->f_type == DTYPE_VNODE)) { 701 lf.l_whence = SEEK_SET; 702 lf.l_start = 0; 703 lf.l_len = 0; 704 lf.l_type = F_UNLCK; 705 mutex_exit(&fdp->fd_lock); 706 (void)VOP_ADVLOCK(fp->f_data, p, F_UNLCK, &lf, F_POSIX); 707 mutex_enter(&fdp->fd_lock); 708 } 709 710 /* Free descriptor slot. */ 711 fd_unused(fdp, fd); 712 mutex_exit(&fdp->fd_lock); 713 714 /* Now drop reference to the file itself. */ 715 return closef(fp); 716 } 717 718 /* 719 * Duplicate a file descriptor. 720 */ 721 int 722 fd_dup(file_t *fp, int minfd, int *newp, bool exclose) 723 { 724 proc_t *p = curproc; 725 int error; 726 727 while ((error = fd_alloc(p, minfd, newp)) != 0) { 728 if (error != ENOSPC) { 729 return error; 730 } 731 fd_tryexpand(p); 732 } 733 734 curlwp->l_fd->fd_dt->dt_ff[*newp]->ff_exclose = exclose; 735 fd_affix(p, fp, *newp); 736 return 0; 737 } 738 739 /* 740 * dup2 operation. 741 */ 742 int 743 fd_dup2(file_t *fp, unsigned new, int flags) 744 { 745 filedesc_t *fdp = curlwp->l_fd; 746 fdfile_t *ff; 747 fdtab_t *dt; 748 749 if (flags & ~(O_CLOEXEC|O_NONBLOCK)) 750 return EINVAL; 751 /* 752 * Ensure there are enough slots in the descriptor table, 753 * and allocate an fdfile_t up front in case we need it. 754 */ 755 while (new >= fdp->fd_dt->dt_nfiles) { 756 fd_tryexpand(curproc); 757 } 758 ff = pool_cache_get(fdfile_cache, PR_WAITOK); 759 760 /* 761 * If there is already a file open, close it. If the file is 762 * half open, wait for it to be constructed before closing it. 763 * XXX Potential for deadlock here? 764 */ 765 mutex_enter(&fdp->fd_lock); 766 while (fd_isused(fdp, new)) { 767 mutex_exit(&fdp->fd_lock); 768 if (fd_getfile(new) != NULL) { 769 (void)fd_close(new); 770 } else { 771 /* 772 * Crummy, but unlikely to happen. 773 * Can occur if we interrupt another 774 * thread while it is opening a file. 775 */ 776 kpause("dup2", false, 1, NULL); 777 } 778 mutex_enter(&fdp->fd_lock); 779 } 780 dt = fdp->fd_dt; 781 if (dt->dt_ff[new] == NULL) { 782 KASSERT(new >= NDFDFILE); 783 dt->dt_ff[new] = ff; 784 ff = NULL; 785 } 786 fd_used(fdp, new); 787 mutex_exit(&fdp->fd_lock); 788 789 dt->dt_ff[new]->ff_exclose = (flags & O_CLOEXEC) != 0; 790 fp->f_flag |= flags & FNONBLOCK; 791 /* Slot is now allocated. Insert copy of the file. */ 792 fd_affix(curproc, fp, new); 793 if (ff != NULL) { 794 pool_cache_put(fdfile_cache, ff); 795 } 796 return 0; 797 } 798 799 /* 800 * Drop reference to a file structure. 801 */ 802 int 803 closef(file_t *fp) 804 { 805 struct flock lf; 806 int error; 807 808 /* 809 * Drop reference. If referenced elsewhere it's still open 810 * and we have nothing more to do. 811 */ 812 mutex_enter(&fp->f_lock); 813 KASSERT(fp->f_count > 0); 814 if (--fp->f_count > 0) { 815 mutex_exit(&fp->f_lock); 816 return 0; 817 } 818 KASSERT(fp->f_count == 0); 819 mutex_exit(&fp->f_lock); 820 821 /* We held the last reference - release locks, close and free. */ 822 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) { 823 lf.l_whence = SEEK_SET; 824 lf.l_start = 0; 825 lf.l_len = 0; 826 lf.l_type = F_UNLCK; 827 (void)VOP_ADVLOCK(fp->f_data, fp, F_UNLCK, &lf, F_FLOCK); 828 } 829 if (fp->f_ops != NULL) { 830 error = (*fp->f_ops->fo_close)(fp); 831 } else { 832 error = 0; 833 } 834 KASSERT(fp->f_count == 0); 835 KASSERT(fp->f_cred != NULL); 836 pool_cache_put(file_cache, fp); 837 838 return error; 839 } 840 841 /* 842 * Allocate a file descriptor for the process. 843 */ 844 int 845 fd_alloc(proc_t *p, int want, int *result) 846 { 847 filedesc_t *fdp = p->p_fd; 848 int i, lim, last, error; 849 u_int off, new; 850 fdtab_t *dt; 851 852 KASSERT(p == curproc || p == &proc0); 853 854 /* 855 * Search for a free descriptor starting at the higher 856 * of want or fd_freefile. 857 */ 858 mutex_enter(&fdp->fd_lock); 859 fd_checkmaps(fdp); 860 dt = fdp->fd_dt; 861 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 862 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles); 863 last = min(dt->dt_nfiles, lim); 864 for (;;) { 865 if ((i = want) < fdp->fd_freefile) 866 i = fdp->fd_freefile; 867 off = i >> NDENTRYSHIFT; 868 new = fd_next_zero(fdp, fdp->fd_himap, off, 869 (last + NDENTRIES - 1) >> NDENTRYSHIFT); 870 if (new == -1) 871 break; 872 i = fd_next_zero(fdp, &fdp->fd_lomap[new], 873 new > off ? 0 : i & NDENTRYMASK, NDENTRIES); 874 if (i == -1) { 875 /* 876 * Free file descriptor in this block was 877 * below want, try again with higher want. 878 */ 879 want = (new + 1) << NDENTRYSHIFT; 880 continue; 881 } 882 i += (new << NDENTRYSHIFT); 883 if (i >= last) { 884 break; 885 } 886 if (dt->dt_ff[i] == NULL) { 887 KASSERT(i >= NDFDFILE); 888 dt->dt_ff[i] = pool_cache_get(fdfile_cache, PR_WAITOK); 889 } 890 KASSERT(dt->dt_ff[i]->ff_file == NULL); 891 fd_used(fdp, i); 892 if (want <= fdp->fd_freefile) { 893 fdp->fd_freefile = i; 894 } 895 *result = i; 896 KASSERT(i >= NDFDFILE || 897 dt->dt_ff[i] == (fdfile_t *)fdp->fd_dfdfile[i]); 898 fd_checkmaps(fdp); 899 mutex_exit(&fdp->fd_lock); 900 return 0; 901 } 902 903 /* No space in current array. Let the caller expand and retry. */ 904 error = (dt->dt_nfiles >= lim) ? EMFILE : ENOSPC; 905 mutex_exit(&fdp->fd_lock); 906 return error; 907 } 908 909 /* 910 * Allocate memory for a descriptor table. 911 */ 912 static fdtab_t * 913 fd_dtab_alloc(int n) 914 { 915 fdtab_t *dt; 916 size_t sz; 917 918 KASSERT(n > NDFILE); 919 920 sz = sizeof(*dt) + (n - NDFILE) * sizeof(dt->dt_ff[0]); 921 dt = kmem_alloc(sz, KM_SLEEP); 922 #ifdef DIAGNOSTIC 923 memset(dt, 0xff, sz); 924 #endif 925 dt->dt_nfiles = n; 926 dt->dt_link = NULL; 927 return dt; 928 } 929 930 /* 931 * Free a descriptor table, and all tables linked for deferred free. 932 */ 933 static void 934 fd_dtab_free(fdtab_t *dt) 935 { 936 fdtab_t *next; 937 size_t sz; 938 939 do { 940 next = dt->dt_link; 941 KASSERT(dt->dt_nfiles > NDFILE); 942 sz = sizeof(*dt) + 943 (dt->dt_nfiles - NDFILE) * sizeof(dt->dt_ff[0]); 944 #ifdef DIAGNOSTIC 945 memset(dt, 0xff, sz); 946 #endif 947 kmem_free(dt, sz); 948 dt = next; 949 } while (dt != NULL); 950 } 951 952 /* 953 * Allocate descriptor bitmap. 954 */ 955 static void 956 fd_map_alloc(int n, uint32_t **lo, uint32_t **hi) 957 { 958 uint8_t *ptr; 959 size_t szlo, szhi; 960 961 KASSERT(n > NDENTRIES); 962 963 szlo = NDLOSLOTS(n) * sizeof(uint32_t); 964 szhi = NDHISLOTS(n) * sizeof(uint32_t); 965 ptr = kmem_alloc(szlo + szhi, KM_SLEEP); 966 *lo = (uint32_t *)ptr; 967 *hi = (uint32_t *)(ptr + szlo); 968 } 969 970 /* 971 * Free descriptor bitmap. 972 */ 973 static void 974 fd_map_free(int n, uint32_t *lo, uint32_t *hi) 975 { 976 size_t szlo, szhi; 977 978 KASSERT(n > NDENTRIES); 979 980 szlo = NDLOSLOTS(n) * sizeof(uint32_t); 981 szhi = NDHISLOTS(n) * sizeof(uint32_t); 982 KASSERT(hi == (uint32_t *)((uint8_t *)lo + szlo)); 983 kmem_free(lo, szlo + szhi); 984 } 985 986 /* 987 * Expand a process' descriptor table. 988 */ 989 void 990 fd_tryexpand(proc_t *p) 991 { 992 filedesc_t *fdp; 993 int i, numfiles, oldnfiles; 994 fdtab_t *newdt, *dt; 995 uint32_t *newhimap, *newlomap; 996 997 KASSERT(p == curproc || p == &proc0); 998 999 fdp = p->p_fd; 1000 newhimap = NULL; 1001 newlomap = NULL; 1002 oldnfiles = fdp->fd_dt->dt_nfiles; 1003 1004 if (oldnfiles < NDEXTENT) 1005 numfiles = NDEXTENT; 1006 else 1007 numfiles = 2 * oldnfiles; 1008 1009 newdt = fd_dtab_alloc(numfiles); 1010 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1011 fd_map_alloc(numfiles, &newlomap, &newhimap); 1012 } 1013 1014 mutex_enter(&fdp->fd_lock); 1015 dt = fdp->fd_dt; 1016 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1017 if (dt->dt_nfiles != oldnfiles) { 1018 /* fdp changed; caller must retry */ 1019 mutex_exit(&fdp->fd_lock); 1020 fd_dtab_free(newdt); 1021 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1022 fd_map_free(numfiles, newlomap, newhimap); 1023 } 1024 return; 1025 } 1026 1027 /* Copy the existing descriptor table and zero the new portion. */ 1028 i = sizeof(fdfile_t *) * oldnfiles; 1029 memcpy(newdt->dt_ff, dt->dt_ff, i); 1030 memset((uint8_t *)newdt->dt_ff + i, 0, 1031 numfiles * sizeof(fdfile_t *) - i); 1032 1033 /* 1034 * Link old descriptor array into list to be discarded. We defer 1035 * freeing until the last reference to the descriptor table goes 1036 * away (usually process exit). This allows us to do lockless 1037 * lookups in fd_getfile(). 1038 */ 1039 if (oldnfiles > NDFILE) { 1040 if (fdp->fd_refcnt > 1) { 1041 newdt->dt_link = dt; 1042 } else { 1043 fd_dtab_free(dt); 1044 } 1045 } 1046 1047 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { 1048 i = NDHISLOTS(oldnfiles) * sizeof(uint32_t); 1049 memcpy(newhimap, fdp->fd_himap, i); 1050 memset((uint8_t *)newhimap + i, 0, 1051 NDHISLOTS(numfiles) * sizeof(uint32_t) - i); 1052 1053 i = NDLOSLOTS(oldnfiles) * sizeof(uint32_t); 1054 memcpy(newlomap, fdp->fd_lomap, i); 1055 memset((uint8_t *)newlomap + i, 0, 1056 NDLOSLOTS(numfiles) * sizeof(uint32_t) - i); 1057 1058 if (NDHISLOTS(oldnfiles) > NDHISLOTS(NDFILE)) { 1059 fd_map_free(oldnfiles, fdp->fd_lomap, fdp->fd_himap); 1060 } 1061 fdp->fd_himap = newhimap; 1062 fdp->fd_lomap = newlomap; 1063 } 1064 1065 /* 1066 * All other modifications must become globally visible before 1067 * the change to fd_dt. See fd_getfile(). 1068 */ 1069 membar_producer(); 1070 fdp->fd_dt = newdt; 1071 KASSERT(newdt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1072 fd_checkmaps(fdp); 1073 mutex_exit(&fdp->fd_lock); 1074 } 1075 1076 /* 1077 * Create a new open file structure and allocate a file descriptor 1078 * for the current process. 1079 */ 1080 int 1081 fd_allocfile(file_t **resultfp, int *resultfd) 1082 { 1083 proc_t *p = curproc; 1084 kauth_cred_t cred; 1085 file_t *fp; 1086 int error; 1087 1088 while ((error = fd_alloc(p, 0, resultfd)) != 0) { 1089 if (error != ENOSPC) { 1090 return error; 1091 } 1092 fd_tryexpand(p); 1093 } 1094 1095 fp = pool_cache_get(file_cache, PR_WAITOK); 1096 if (fp == NULL) { 1097 fd_abort(p, NULL, *resultfd); 1098 return ENFILE; 1099 } 1100 KASSERT(fp->f_count == 0); 1101 KASSERT(fp->f_msgcount == 0); 1102 KASSERT(fp->f_unpcount == 0); 1103 1104 /* Replace cached credentials if not what we need. */ 1105 cred = curlwp->l_cred; 1106 if (__predict_false(cred != fp->f_cred)) { 1107 kauth_cred_free(fp->f_cred); 1108 kauth_cred_hold(cred); 1109 fp->f_cred = cred; 1110 } 1111 1112 /* 1113 * Don't allow recycled files to be scanned. 1114 * See uipc_usrreq.c. 1115 */ 1116 if (__predict_false((fp->f_flag & FSCAN) != 0)) { 1117 mutex_enter(&fp->f_lock); 1118 atomic_and_uint(&fp->f_flag, ~FSCAN); 1119 mutex_exit(&fp->f_lock); 1120 } 1121 1122 fp->f_advice = 0; 1123 fp->f_offset = 0; 1124 *resultfp = fp; 1125 1126 return 0; 1127 } 1128 1129 /* 1130 * Successful creation of a new descriptor: make visible to the process. 1131 */ 1132 void 1133 fd_affix(proc_t *p, file_t *fp, unsigned fd) 1134 { 1135 fdfile_t *ff; 1136 filedesc_t *fdp; 1137 1138 KASSERT(p == curproc || p == &proc0); 1139 1140 /* Add a reference to the file structure. */ 1141 mutex_enter(&fp->f_lock); 1142 fp->f_count++; 1143 mutex_exit(&fp->f_lock); 1144 1145 /* 1146 * Insert the new file into the descriptor slot. 1147 * 1148 * The memory barriers provided by lock activity in this routine 1149 * ensure that any updates to the file structure become globally 1150 * visible before the file becomes visible to other LWPs in the 1151 * current process. 1152 */ 1153 fdp = p->p_fd; 1154 ff = fdp->fd_dt->dt_ff[fd]; 1155 1156 KASSERT(ff != NULL); 1157 KASSERT(ff->ff_file == NULL); 1158 KASSERT(ff->ff_allocated); 1159 KASSERT(fd_isused(fdp, fd)); 1160 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1161 1162 /* No need to lock in order to make file initially visible. */ 1163 ff->ff_file = fp; 1164 } 1165 1166 /* 1167 * Abort creation of a new descriptor: free descriptor slot and file. 1168 */ 1169 void 1170 fd_abort(proc_t *p, file_t *fp, unsigned fd) 1171 { 1172 filedesc_t *fdp; 1173 fdfile_t *ff; 1174 1175 KASSERT(p == curproc || p == &proc0); 1176 1177 fdp = p->p_fd; 1178 ff = fdp->fd_dt->dt_ff[fd]; 1179 ff->ff_exclose = false; 1180 1181 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1182 1183 mutex_enter(&fdp->fd_lock); 1184 KASSERT(fd_isused(fdp, fd)); 1185 fd_unused(fdp, fd); 1186 mutex_exit(&fdp->fd_lock); 1187 1188 if (fp != NULL) { 1189 KASSERT(fp->f_count == 0); 1190 KASSERT(fp->f_cred != NULL); 1191 pool_cache_put(file_cache, fp); 1192 } 1193 } 1194 1195 static int 1196 file_ctor(void *arg, void *obj, int flags) 1197 { 1198 file_t *fp = obj; 1199 1200 memset(fp, 0, sizeof(*fp)); 1201 1202 mutex_enter(&filelist_lock); 1203 if (__predict_false(nfiles >= maxfiles)) { 1204 mutex_exit(&filelist_lock); 1205 tablefull("file", "increase kern.maxfiles or MAXFILES"); 1206 return ENFILE; 1207 } 1208 nfiles++; 1209 LIST_INSERT_HEAD(&filehead, fp, f_list); 1210 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); 1211 fp->f_cred = curlwp->l_cred; 1212 kauth_cred_hold(fp->f_cred); 1213 mutex_exit(&filelist_lock); 1214 1215 return 0; 1216 } 1217 1218 static void 1219 file_dtor(void *arg, void *obj) 1220 { 1221 file_t *fp = obj; 1222 1223 mutex_enter(&filelist_lock); 1224 nfiles--; 1225 LIST_REMOVE(fp, f_list); 1226 mutex_exit(&filelist_lock); 1227 1228 kauth_cred_free(fp->f_cred); 1229 mutex_destroy(&fp->f_lock); 1230 } 1231 1232 static int 1233 fdfile_ctor(void *arg, void *obj, int flags) 1234 { 1235 fdfile_t *ff = obj; 1236 1237 memset(ff, 0, sizeof(*ff)); 1238 cv_init(&ff->ff_closing, "fdclose"); 1239 1240 return 0; 1241 } 1242 1243 static void 1244 fdfile_dtor(void *arg, void *obj) 1245 { 1246 fdfile_t *ff = obj; 1247 1248 cv_destroy(&ff->ff_closing); 1249 } 1250 1251 file_t * 1252 fgetdummy(void) 1253 { 1254 file_t *fp; 1255 1256 fp = kmem_zalloc(sizeof(*fp), KM_SLEEP); 1257 if (fp != NULL) { 1258 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); 1259 } 1260 return fp; 1261 } 1262 1263 void 1264 fputdummy(file_t *fp) 1265 { 1266 1267 mutex_destroy(&fp->f_lock); 1268 kmem_free(fp, sizeof(*fp)); 1269 } 1270 1271 /* 1272 * Create an initial filedesc structure. 1273 */ 1274 filedesc_t * 1275 fd_init(filedesc_t *fdp) 1276 { 1277 #ifdef DIAGNOSTIC 1278 unsigned fd; 1279 #endif 1280 1281 if (__predict_true(fdp == NULL)) { 1282 fdp = pool_cache_get(filedesc_cache, PR_WAITOK); 1283 } else { 1284 KASSERT(fdp == &filedesc0); 1285 filedesc_ctor(NULL, fdp, PR_WAITOK); 1286 } 1287 1288 #ifdef DIAGNOSTIC 1289 KASSERT(fdp->fd_lastfile == -1); 1290 KASSERT(fdp->fd_lastkqfile == -1); 1291 KASSERT(fdp->fd_knhash == NULL); 1292 KASSERT(fdp->fd_freefile == 0); 1293 KASSERT(fdp->fd_exclose == false); 1294 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin); 1295 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1296 for (fd = 0; fd < NDFDFILE; fd++) { 1297 KASSERT(fdp->fd_dtbuiltin.dt_ff[fd] == 1298 (fdfile_t *)fdp->fd_dfdfile[fd]); 1299 } 1300 for (fd = NDFDFILE; fd < NDFILE; fd++) { 1301 KASSERT(fdp->fd_dtbuiltin.dt_ff[fd] == NULL); 1302 } 1303 KASSERT(fdp->fd_himap == fdp->fd_dhimap); 1304 KASSERT(fdp->fd_lomap == fdp->fd_dlomap); 1305 #endif /* DIAGNOSTIC */ 1306 1307 fdp->fd_refcnt = 1; 1308 fd_checkmaps(fdp); 1309 1310 return fdp; 1311 } 1312 1313 /* 1314 * Initialize a file descriptor table. 1315 */ 1316 static int 1317 filedesc_ctor(void *arg, void *obj, int flag) 1318 { 1319 filedesc_t *fdp = obj; 1320 fdfile_t **ffp; 1321 int i; 1322 1323 memset(fdp, 0, sizeof(*fdp)); 1324 mutex_init(&fdp->fd_lock, MUTEX_DEFAULT, IPL_NONE); 1325 fdp->fd_lastfile = -1; 1326 fdp->fd_lastkqfile = -1; 1327 fdp->fd_dt = &fdp->fd_dtbuiltin; 1328 fdp->fd_dtbuiltin.dt_nfiles = NDFILE; 1329 fdp->fd_himap = fdp->fd_dhimap; 1330 fdp->fd_lomap = fdp->fd_dlomap; 1331 1332 CTASSERT(sizeof(fdp->fd_dfdfile[0]) >= sizeof(fdfile_t)); 1333 for (i = 0, ffp = fdp->fd_dt->dt_ff; i < NDFDFILE; i++, ffp++) { 1334 *ffp = (fdfile_t *)fdp->fd_dfdfile[i]; 1335 (void)fdfile_ctor(NULL, fdp->fd_dfdfile[i], PR_WAITOK); 1336 } 1337 1338 return 0; 1339 } 1340 1341 static void 1342 filedesc_dtor(void *arg, void *obj) 1343 { 1344 filedesc_t *fdp = obj; 1345 int i; 1346 1347 for (i = 0; i < NDFDFILE; i++) { 1348 fdfile_dtor(NULL, fdp->fd_dfdfile[i]); 1349 } 1350 1351 mutex_destroy(&fdp->fd_lock); 1352 } 1353 1354 /* 1355 * Make p share curproc's filedesc structure. 1356 */ 1357 void 1358 fd_share(struct proc *p) 1359 { 1360 filedesc_t *fdp; 1361 1362 fdp = curlwp->l_fd; 1363 p->p_fd = fdp; 1364 atomic_inc_uint(&fdp->fd_refcnt); 1365 } 1366 1367 /* 1368 * Acquire a hold on a filedesc structure. 1369 */ 1370 void 1371 fd_hold(lwp_t *l) 1372 { 1373 filedesc_t *fdp = l->l_fd; 1374 1375 atomic_inc_uint(&fdp->fd_refcnt); 1376 } 1377 1378 /* 1379 * Copy a filedesc structure. 1380 */ 1381 filedesc_t * 1382 fd_copy(void) 1383 { 1384 filedesc_t *newfdp, *fdp; 1385 fdfile_t *ff, **ffp, **nffp, *ff2; 1386 int i, j, numfiles, lastfile, newlast; 1387 file_t *fp; 1388 fdtab_t *newdt; 1389 1390 fdp = curproc->p_fd; 1391 newfdp = pool_cache_get(filedesc_cache, PR_WAITOK); 1392 newfdp->fd_refcnt = 1; 1393 1394 #ifdef DIAGNOSTIC 1395 KASSERT(newfdp->fd_lastfile == -1); 1396 KASSERT(newfdp->fd_lastkqfile == -1); 1397 KASSERT(newfdp->fd_knhash == NULL); 1398 KASSERT(newfdp->fd_freefile == 0); 1399 KASSERT(newfdp->fd_exclose == false); 1400 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin); 1401 KASSERT(newfdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1402 for (i = 0; i < NDFDFILE; i++) { 1403 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == 1404 (fdfile_t *)&newfdp->fd_dfdfile[i]); 1405 } 1406 for (i = NDFDFILE; i < NDFILE; i++) { 1407 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == NULL); 1408 } 1409 #endif /* DIAGNOSTIC */ 1410 1411 mutex_enter(&fdp->fd_lock); 1412 fd_checkmaps(fdp); 1413 numfiles = fdp->fd_dt->dt_nfiles; 1414 lastfile = fdp->fd_lastfile; 1415 1416 /* 1417 * If the number of open files fits in the internal arrays 1418 * of the open file structure, use them, otherwise allocate 1419 * additional memory for the number of descriptors currently 1420 * in use. 1421 */ 1422 if (lastfile < NDFILE) { 1423 i = NDFILE; 1424 newdt = newfdp->fd_dt; 1425 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin); 1426 } else { 1427 /* 1428 * Compute the smallest multiple of NDEXTENT needed 1429 * for the file descriptors currently in use, 1430 * allowing the table to shrink. 1431 */ 1432 i = numfiles; 1433 while (i >= 2 * NDEXTENT && i > lastfile * 2) { 1434 i /= 2; 1435 } 1436 KASSERT(i > NDFILE); 1437 newdt = fd_dtab_alloc(i); 1438 newfdp->fd_dt = newdt; 1439 memcpy(newdt->dt_ff, newfdp->fd_dtbuiltin.dt_ff, 1440 NDFDFILE * sizeof(fdfile_t **)); 1441 memset(newdt->dt_ff + NDFDFILE, 0, 1442 (i - NDFDFILE) * sizeof(fdfile_t **)); 1443 } 1444 if (NDHISLOTS(i) <= NDHISLOTS(NDFILE)) { 1445 newfdp->fd_himap = newfdp->fd_dhimap; 1446 newfdp->fd_lomap = newfdp->fd_dlomap; 1447 } else { 1448 fd_map_alloc(i, &newfdp->fd_lomap, &newfdp->fd_himap); 1449 KASSERT(i >= NDENTRIES * NDENTRIES); 1450 memset(newfdp->fd_himap, 0, NDHISLOTS(i)*sizeof(uint32_t)); 1451 memset(newfdp->fd_lomap, 0, NDLOSLOTS(i)*sizeof(uint32_t)); 1452 } 1453 newfdp->fd_freefile = fdp->fd_freefile; 1454 newfdp->fd_exclose = fdp->fd_exclose; 1455 1456 ffp = fdp->fd_dt->dt_ff; 1457 nffp = newdt->dt_ff; 1458 newlast = -1; 1459 for (i = 0; i <= (int)lastfile; i++, ffp++, nffp++) { 1460 KASSERT(i >= NDFDFILE || 1461 *nffp == (fdfile_t *)newfdp->fd_dfdfile[i]); 1462 ff = *ffp; 1463 if (ff == NULL || (fp = ff->ff_file) == NULL) { 1464 /* Descriptor unused, or descriptor half open. */ 1465 KASSERT(!fd_isused(newfdp, i)); 1466 continue; 1467 } 1468 if (__predict_false(fp->f_type == DTYPE_KQUEUE)) { 1469 /* kqueue descriptors cannot be copied. */ 1470 if (i < newfdp->fd_freefile) { 1471 newfdp->fd_freefile = i; 1472 } 1473 continue; 1474 } 1475 /* It's active: add a reference to the file. */ 1476 mutex_enter(&fp->f_lock); 1477 fp->f_count++; 1478 mutex_exit(&fp->f_lock); 1479 1480 /* Allocate an fdfile_t to represent it. */ 1481 if (i >= NDFDFILE) { 1482 ff2 = pool_cache_get(fdfile_cache, PR_WAITOK); 1483 *nffp = ff2; 1484 } else { 1485 ff2 = newdt->dt_ff[i]; 1486 } 1487 ff2->ff_file = fp; 1488 ff2->ff_exclose = ff->ff_exclose; 1489 ff2->ff_allocated = true; 1490 1491 /* Fix up bitmaps. */ 1492 j = i >> NDENTRYSHIFT; 1493 KASSERT((newfdp->fd_lomap[j] & (1 << (i & NDENTRYMASK))) == 0); 1494 newfdp->fd_lomap[j] |= 1 << (i & NDENTRYMASK); 1495 if (__predict_false(newfdp->fd_lomap[j] == ~0)) { 1496 KASSERT((newfdp->fd_himap[j >> NDENTRYSHIFT] & 1497 (1 << (j & NDENTRYMASK))) == 0); 1498 newfdp->fd_himap[j >> NDENTRYSHIFT] |= 1499 1 << (j & NDENTRYMASK); 1500 } 1501 newlast = i; 1502 } 1503 KASSERT(newdt->dt_ff[0] == (fdfile_t *)newfdp->fd_dfdfile[0]); 1504 newfdp->fd_lastfile = newlast; 1505 fd_checkmaps(newfdp); 1506 mutex_exit(&fdp->fd_lock); 1507 1508 return newfdp; 1509 } 1510 1511 /* 1512 * Release a filedesc structure. 1513 */ 1514 void 1515 fd_free(void) 1516 { 1517 fdfile_t *ff; 1518 file_t *fp; 1519 int fd, nf; 1520 fdtab_t *dt; 1521 lwp_t * const l = curlwp; 1522 filedesc_t * const fdp = l->l_fd; 1523 const bool noadvlock = (l->l_proc->p_flag & PK_ADVLOCK) == 0; 1524 1525 KASSERT(fdp->fd_dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]); 1526 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1527 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL); 1528 1529 #ifndef __HAVE_ATOMIC_AS_MEMBAR 1530 membar_exit(); 1531 #endif 1532 if (atomic_dec_uint_nv(&fdp->fd_refcnt) > 0) 1533 return; 1534 1535 /* 1536 * Close any files that the process holds open. 1537 */ 1538 dt = fdp->fd_dt; 1539 fd_checkmaps(fdp); 1540 #ifdef DEBUG 1541 fdp->fd_refcnt = -1; /* see fd_checkmaps */ 1542 #endif 1543 for (fd = 0, nf = dt->dt_nfiles; fd < nf; fd++) { 1544 ff = dt->dt_ff[fd]; 1545 KASSERT(fd >= NDFDFILE || 1546 ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1547 if (ff == NULL) 1548 continue; 1549 if ((fp = ff->ff_file) != NULL) { 1550 /* 1551 * Must use fd_close() here if there is 1552 * a reference from kqueue or we might have posix 1553 * advisory locks. 1554 */ 1555 if (__predict_true(ff->ff_refcnt == 0) && 1556 (noadvlock || fp->f_type != DTYPE_VNODE)) { 1557 ff->ff_file = NULL; 1558 ff->ff_exclose = false; 1559 ff->ff_allocated = false; 1560 closef(fp); 1561 } else { 1562 ff->ff_refcnt++; 1563 fd_close(fd); 1564 } 1565 } 1566 KASSERT(ff->ff_refcnt == 0); 1567 KASSERT(ff->ff_file == NULL); 1568 KASSERT(!ff->ff_exclose); 1569 KASSERT(!ff->ff_allocated); 1570 if (fd >= NDFDFILE) { 1571 pool_cache_put(fdfile_cache, ff); 1572 dt->dt_ff[fd] = NULL; 1573 } 1574 } 1575 1576 /* 1577 * Clean out the descriptor table for the next user and return 1578 * to the cache. 1579 */ 1580 if (__predict_false(dt != &fdp->fd_dtbuiltin)) { 1581 fd_dtab_free(fdp->fd_dt); 1582 /* Otherwise, done above. */ 1583 memset(&fdp->fd_dtbuiltin.dt_ff[NDFDFILE], 0, 1584 (NDFILE - NDFDFILE) * sizeof(fdp->fd_dtbuiltin.dt_ff[0])); 1585 fdp->fd_dt = &fdp->fd_dtbuiltin; 1586 } 1587 if (__predict_false(NDHISLOTS(nf) > NDHISLOTS(NDFILE))) { 1588 KASSERT(fdp->fd_himap != fdp->fd_dhimap); 1589 KASSERT(fdp->fd_lomap != fdp->fd_dlomap); 1590 fd_map_free(nf, fdp->fd_lomap, fdp->fd_himap); 1591 } 1592 if (__predict_false(fdp->fd_knhash != NULL)) { 1593 hashdone(fdp->fd_knhash, HASH_LIST, fdp->fd_knhashmask); 1594 fdp->fd_knhash = NULL; 1595 fdp->fd_knhashmask = 0; 1596 } else { 1597 KASSERT(fdp->fd_knhashmask == 0); 1598 } 1599 fdp->fd_dt = &fdp->fd_dtbuiltin; 1600 fdp->fd_lastkqfile = -1; 1601 fdp->fd_lastfile = -1; 1602 fdp->fd_freefile = 0; 1603 fdp->fd_exclose = false; 1604 memset(&fdp->fd_startzero, 0, sizeof(*fdp) - 1605 offsetof(filedesc_t, fd_startzero)); 1606 fdp->fd_himap = fdp->fd_dhimap; 1607 fdp->fd_lomap = fdp->fd_dlomap; 1608 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE); 1609 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL); 1610 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin); 1611 #ifdef DEBUG 1612 fdp->fd_refcnt = 0; /* see fd_checkmaps */ 1613 #endif 1614 fd_checkmaps(fdp); 1615 pool_cache_put(filedesc_cache, fdp); 1616 } 1617 1618 /* 1619 * File Descriptor pseudo-device driver (/dev/fd/). 1620 * 1621 * Opening minor device N dup()s the file (if any) connected to file 1622 * descriptor N belonging to the calling process. Note that this driver 1623 * consists of only the ``open()'' routine, because all subsequent 1624 * references to this file will be direct to the other driver. 1625 */ 1626 static int 1627 filedescopen(dev_t dev, int mode, int type, lwp_t *l) 1628 { 1629 1630 /* 1631 * XXX Kludge: set dupfd to contain the value of the 1632 * the file descriptor being sought for duplication. The error 1633 * return ensures that the vnode for this device will be released 1634 * by vn_open. Open will detect this special error and take the 1635 * actions in fd_dupopen below. Other callers of vn_open or VOP_OPEN 1636 * will simply report the error. 1637 */ 1638 l->l_dupfd = minor(dev); /* XXX */ 1639 return EDUPFD; 1640 } 1641 1642 /* 1643 * Duplicate the specified descriptor to a free descriptor. 1644 */ 1645 int 1646 fd_dupopen(int old, int *new, int mode, int error) 1647 { 1648 filedesc_t *fdp; 1649 fdfile_t *ff; 1650 file_t *fp; 1651 fdtab_t *dt; 1652 1653 if ((fp = fd_getfile(old)) == NULL) { 1654 return EBADF; 1655 } 1656 fdp = curlwp->l_fd; 1657 dt = fdp->fd_dt; 1658 ff = dt->dt_ff[old]; 1659 1660 /* 1661 * There are two cases of interest here. 1662 * 1663 * For EDUPFD simply dup (old) to file descriptor 1664 * (new) and return. 1665 * 1666 * For EMOVEFD steal away the file structure from (old) and 1667 * store it in (new). (old) is effectively closed by 1668 * this operation. 1669 * 1670 * Any other error code is just returned. 1671 */ 1672 switch (error) { 1673 case EDUPFD: 1674 /* 1675 * Check that the mode the file is being opened for is a 1676 * subset of the mode of the existing descriptor. 1677 */ 1678 if (((mode & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) { 1679 error = EACCES; 1680 break; 1681 } 1682 1683 /* Copy it. */ 1684 error = fd_dup(fp, 0, new, ff->ff_exclose); 1685 break; 1686 1687 case EMOVEFD: 1688 /* Copy it. */ 1689 error = fd_dup(fp, 0, new, ff->ff_exclose); 1690 if (error != 0) { 1691 break; 1692 } 1693 1694 /* Steal away the file pointer from 'old'. */ 1695 (void)fd_close(old); 1696 return 0; 1697 } 1698 1699 fd_putfile(old); 1700 return error; 1701 } 1702 1703 /* 1704 * Close open files on exec. 1705 */ 1706 void 1707 fd_closeexec(void) 1708 { 1709 proc_t *p; 1710 filedesc_t *fdp; 1711 fdfile_t *ff; 1712 lwp_t *l; 1713 fdtab_t *dt; 1714 int fd; 1715 1716 l = curlwp; 1717 p = l->l_proc; 1718 fdp = p->p_fd; 1719 1720 if (fdp->fd_refcnt > 1) { 1721 fdp = fd_copy(); 1722 fd_free(); 1723 p->p_fd = fdp; 1724 l->l_fd = fdp; 1725 } 1726 if (!fdp->fd_exclose) { 1727 return; 1728 } 1729 fdp->fd_exclose = false; 1730 dt = fdp->fd_dt; 1731 1732 for (fd = 0; fd <= fdp->fd_lastfile; fd++) { 1733 if ((ff = dt->dt_ff[fd]) == NULL) { 1734 KASSERT(fd >= NDFDFILE); 1735 continue; 1736 } 1737 KASSERT(fd >= NDFDFILE || 1738 ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 1739 if (ff->ff_file == NULL) 1740 continue; 1741 if (ff->ff_exclose) { 1742 /* 1743 * We need a reference to close the file. 1744 * No other threads can see the fdfile_t at 1745 * this point, so don't bother locking. 1746 */ 1747 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); 1748 ff->ff_refcnt++; 1749 fd_close(fd); 1750 } 1751 } 1752 } 1753 1754 /* 1755 * Sets descriptor owner. If the owner is a process, 'pgid' 1756 * is set to positive value, process ID. If the owner is process group, 1757 * 'pgid' is set to -pg_id. 1758 */ 1759 int 1760 fsetown(pid_t *pgid, u_long cmd, const void *data) 1761 { 1762 pid_t id = *(const pid_t *)data; 1763 int error; 1764 1765 switch (cmd) { 1766 case TIOCSPGRP: 1767 if (id < 0) 1768 return EINVAL; 1769 id = -id; 1770 break; 1771 default: 1772 break; 1773 } 1774 if (id > 0) { 1775 mutex_enter(proc_lock); 1776 error = proc_find(id) ? 0 : ESRCH; 1777 mutex_exit(proc_lock); 1778 } else if (id < 0) { 1779 error = pgid_in_session(curproc, -id); 1780 } else { 1781 error = 0; 1782 } 1783 if (!error) { 1784 *pgid = id; 1785 } 1786 return error; 1787 } 1788 1789 void 1790 fd_set_exclose(struct lwp *l, int fd, bool exclose) 1791 { 1792 filedesc_t *fdp = l->l_fd; 1793 fdfile_t *ff = fdp->fd_dt->dt_ff[fd]; 1794 1795 ff->ff_exclose = exclose; 1796 if (exclose) 1797 fdp->fd_exclose = true; 1798 } 1799 1800 /* 1801 * Return descriptor owner information. If the value is positive, 1802 * it's process ID. If it's negative, it's process group ID and 1803 * needs the sign removed before use. 1804 */ 1805 int 1806 fgetown(pid_t pgid, u_long cmd, void *data) 1807 { 1808 1809 switch (cmd) { 1810 case TIOCGPGRP: 1811 *(int *)data = -pgid; 1812 break; 1813 default: 1814 *(int *)data = pgid; 1815 break; 1816 } 1817 return 0; 1818 } 1819 1820 /* 1821 * Send signal to descriptor owner, either process or process group. 1822 */ 1823 void 1824 fownsignal(pid_t pgid, int signo, int code, int band, void *fdescdata) 1825 { 1826 ksiginfo_t ksi; 1827 1828 KASSERT(!cpu_intr_p()); 1829 1830 if (pgid == 0) { 1831 return; 1832 } 1833 1834 KSI_INIT(&ksi); 1835 ksi.ksi_signo = signo; 1836 ksi.ksi_code = code; 1837 ksi.ksi_band = band; 1838 1839 mutex_enter(proc_lock); 1840 if (pgid > 0) { 1841 struct proc *p1; 1842 1843 p1 = proc_find(pgid); 1844 if (p1 != NULL) { 1845 kpsignal(p1, &ksi, fdescdata); 1846 } 1847 } else { 1848 struct pgrp *pgrp; 1849 1850 KASSERT(pgid < 0); 1851 pgrp = pgrp_find(-pgid); 1852 if (pgrp != NULL) { 1853 kpgsignal(pgrp, &ksi, fdescdata, 0); 1854 } 1855 } 1856 mutex_exit(proc_lock); 1857 } 1858 1859 int 1860 fd_clone(file_t *fp, unsigned fd, int flag, const struct fileops *fops, 1861 void *data) 1862 { 1863 1864 fp->f_flag = flag; 1865 fp->f_type = DTYPE_MISC; 1866 fp->f_ops = fops; 1867 fp->f_data = data; 1868 curlwp->l_dupfd = fd; 1869 fd_affix(curproc, fp, fd); 1870 1871 return EMOVEFD; 1872 } 1873 1874 int 1875 fnullop_fcntl(file_t *fp, u_int cmd, void *data) 1876 { 1877 1878 if (cmd == F_SETFL) 1879 return 0; 1880 1881 return EOPNOTSUPP; 1882 } 1883 1884 int 1885 fnullop_poll(file_t *fp, int which) 1886 { 1887 1888 return 0; 1889 } 1890 1891 int 1892 fnullop_kqfilter(file_t *fp, struct knote *kn) 1893 { 1894 1895 return EOPNOTSUPP; 1896 } 1897 1898 void 1899 fnullop_restart(file_t *fp) 1900 { 1901 1902 } 1903 1904 int 1905 fbadop_read(file_t *fp, off_t *offset, struct uio *uio, 1906 kauth_cred_t cred, int flags) 1907 { 1908 1909 return EOPNOTSUPP; 1910 } 1911 1912 int 1913 fbadop_write(file_t *fp, off_t *offset, struct uio *uio, 1914 kauth_cred_t cred, int flags) 1915 { 1916 1917 return EOPNOTSUPP; 1918 } 1919 1920 int 1921 fbadop_ioctl(file_t *fp, u_long com, void *data) 1922 { 1923 1924 return EOPNOTSUPP; 1925 } 1926 1927 int 1928 fbadop_stat(file_t *fp, struct stat *sb) 1929 { 1930 1931 return EOPNOTSUPP; 1932 } 1933 1934 int 1935 fbadop_close(file_t *fp) 1936 { 1937 1938 return EOPNOTSUPP; 1939 } 1940 1941 /* 1942 * sysctl routines pertaining to file descriptors 1943 */ 1944 1945 /* Initialized in sysctl_init() for now... */ 1946 extern kmutex_t sysctl_file_marker_lock; 1947 static u_int sysctl_file_marker = 1; 1948 1949 /* 1950 * Expects to be called with proc_lock and sysctl_file_marker_lock locked. 1951 */ 1952 static void 1953 sysctl_file_marker_reset(void) 1954 { 1955 struct proc *p; 1956 1957 PROCLIST_FOREACH(p, &allproc) { 1958 struct filedesc *fd = p->p_fd; 1959 fdtab_t *dt; 1960 u_int i; 1961 1962 mutex_enter(&fd->fd_lock); 1963 dt = fd->fd_dt; 1964 for (i = 0; i < dt->dt_nfiles; i++) { 1965 struct file *fp; 1966 fdfile_t *ff; 1967 1968 if ((ff = dt->dt_ff[i]) == NULL) { 1969 continue; 1970 } 1971 if ((fp = ff->ff_file) == NULL) { 1972 continue; 1973 } 1974 fp->f_marker = 0; 1975 } 1976 mutex_exit(&fd->fd_lock); 1977 } 1978 } 1979 1980 /* 1981 * sysctl helper routine for kern.file pseudo-subtree. 1982 */ 1983 static int 1984 sysctl_kern_file(SYSCTLFN_ARGS) 1985 { 1986 int error; 1987 size_t buflen; 1988 struct file *fp, fbuf; 1989 char *start, *where; 1990 struct proc *p; 1991 1992 start = where = oldp; 1993 buflen = *oldlenp; 1994 1995 if (where == NULL) { 1996 /* 1997 * overestimate by 10 files 1998 */ 1999 *oldlenp = sizeof(filehead) + (nfiles + 10) * 2000 sizeof(struct file); 2001 return 0; 2002 } 2003 2004 /* 2005 * first sysctl_copyout filehead 2006 */ 2007 if (buflen < sizeof(filehead)) { 2008 *oldlenp = 0; 2009 return 0; 2010 } 2011 sysctl_unlock(); 2012 error = sysctl_copyout(l, &filehead, where, sizeof(filehead)); 2013 if (error) { 2014 sysctl_relock(); 2015 return error; 2016 } 2017 buflen -= sizeof(filehead); 2018 where += sizeof(filehead); 2019 2020 /* 2021 * followed by an array of file structures 2022 */ 2023 mutex_enter(&sysctl_file_marker_lock); 2024 mutex_enter(proc_lock); 2025 PROCLIST_FOREACH(p, &allproc) { 2026 struct filedesc *fd; 2027 fdtab_t *dt; 2028 u_int i; 2029 2030 if (p->p_stat == SIDL) { 2031 /* skip embryonic processes */ 2032 continue; 2033 } 2034 mutex_enter(p->p_lock); 2035 error = kauth_authorize_process(l->l_cred, 2036 KAUTH_PROCESS_CANSEE, p, 2037 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES), 2038 NULL, NULL); 2039 mutex_exit(p->p_lock); 2040 if (error != 0) { 2041 /* 2042 * Don't leak kauth retval if we're silently 2043 * skipping this entry. 2044 */ 2045 error = 0; 2046 continue; 2047 } 2048 2049 /* 2050 * Grab a hold on the process. 2051 */ 2052 if (!rw_tryenter(&p->p_reflock, RW_READER)) { 2053 continue; 2054 } 2055 mutex_exit(proc_lock); 2056 2057 fd = p->p_fd; 2058 mutex_enter(&fd->fd_lock); 2059 dt = fd->fd_dt; 2060 for (i = 0; i < dt->dt_nfiles; i++) { 2061 fdfile_t *ff; 2062 2063 if ((ff = dt->dt_ff[i]) == NULL) { 2064 continue; 2065 } 2066 if ((fp = ff->ff_file) == NULL) { 2067 continue; 2068 } 2069 2070 mutex_enter(&fp->f_lock); 2071 2072 if ((fp->f_count == 0) || 2073 (fp->f_marker == sysctl_file_marker)) { 2074 mutex_exit(&fp->f_lock); 2075 continue; 2076 } 2077 2078 /* Check that we have enough space. */ 2079 if (buflen < sizeof(struct file)) { 2080 *oldlenp = where - start; 2081 mutex_exit(&fp->f_lock); 2082 error = ENOMEM; 2083 break; 2084 } 2085 2086 memcpy(&fbuf, fp, sizeof(fbuf)); 2087 mutex_exit(&fp->f_lock); 2088 error = sysctl_copyout(l, &fbuf, where, sizeof(fbuf)); 2089 if (error) { 2090 break; 2091 } 2092 buflen -= sizeof(struct file); 2093 where += sizeof(struct file); 2094 2095 fp->f_marker = sysctl_file_marker; 2096 } 2097 mutex_exit(&fd->fd_lock); 2098 2099 /* 2100 * Release reference to process. 2101 */ 2102 mutex_enter(proc_lock); 2103 rw_exit(&p->p_reflock); 2104 2105 if (error) 2106 break; 2107 } 2108 2109 sysctl_file_marker++; 2110 /* Reset all markers if wrapped. */ 2111 if (sysctl_file_marker == 0) { 2112 sysctl_file_marker_reset(); 2113 sysctl_file_marker++; 2114 } 2115 2116 mutex_exit(proc_lock); 2117 mutex_exit(&sysctl_file_marker_lock); 2118 2119 *oldlenp = where - start; 2120 sysctl_relock(); 2121 return error; 2122 } 2123 2124 /* 2125 * sysctl helper function for kern.file2 2126 */ 2127 static int 2128 sysctl_kern_file2(SYSCTLFN_ARGS) 2129 { 2130 struct proc *p; 2131 struct file *fp; 2132 struct filedesc *fd; 2133 struct kinfo_file kf; 2134 char *dp; 2135 u_int i, op; 2136 size_t len, needed, elem_size, out_size; 2137 int error, arg, elem_count; 2138 fdfile_t *ff; 2139 fdtab_t *dt; 2140 2141 if (namelen == 1 && name[0] == CTL_QUERY) 2142 return sysctl_query(SYSCTLFN_CALL(rnode)); 2143 2144 if (namelen != 4) 2145 return EINVAL; 2146 2147 error = 0; 2148 dp = oldp; 2149 len = (oldp != NULL) ? *oldlenp : 0; 2150 op = name[0]; 2151 arg = name[1]; 2152 elem_size = name[2]; 2153 elem_count = name[3]; 2154 out_size = MIN(sizeof(kf), elem_size); 2155 needed = 0; 2156 2157 if (elem_size < 1 || elem_count < 0) 2158 return EINVAL; 2159 2160 switch (op) { 2161 case KERN_FILE_BYFILE: 2162 case KERN_FILE_BYPID: 2163 /* 2164 * We're traversing the process list in both cases; the BYFILE 2165 * case does additional work of keeping track of files already 2166 * looked at. 2167 */ 2168 2169 /* doesn't use arg so it must be zero */ 2170 if ((op == KERN_FILE_BYFILE) && (arg != 0)) 2171 return EINVAL; 2172 2173 if ((op == KERN_FILE_BYPID) && (arg < -1)) 2174 /* -1 means all processes */ 2175 return EINVAL; 2176 2177 sysctl_unlock(); 2178 if (op == KERN_FILE_BYFILE) 2179 mutex_enter(&sysctl_file_marker_lock); 2180 mutex_enter(proc_lock); 2181 PROCLIST_FOREACH(p, &allproc) { 2182 if (p->p_stat == SIDL) { 2183 /* skip embryonic processes */ 2184 continue; 2185 } 2186 if (arg > 0 && p->p_pid != arg) { 2187 /* pick only the one we want */ 2188 /* XXX want 0 to mean "kernel files" */ 2189 continue; 2190 } 2191 mutex_enter(p->p_lock); 2192 error = kauth_authorize_process(l->l_cred, 2193 KAUTH_PROCESS_CANSEE, p, 2194 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES), 2195 NULL, NULL); 2196 mutex_exit(p->p_lock); 2197 if (error != 0) { 2198 /* 2199 * Don't leak kauth retval if we're silently 2200 * skipping this entry. 2201 */ 2202 error = 0; 2203 continue; 2204 } 2205 2206 /* 2207 * Grab a hold on the process. 2208 */ 2209 if (!rw_tryenter(&p->p_reflock, RW_READER)) { 2210 continue; 2211 } 2212 mutex_exit(proc_lock); 2213 2214 fd = p->p_fd; 2215 mutex_enter(&fd->fd_lock); 2216 dt = fd->fd_dt; 2217 for (i = 0; i < dt->dt_nfiles; i++) { 2218 if ((ff = dt->dt_ff[i]) == NULL) { 2219 continue; 2220 } 2221 if ((fp = ff->ff_file) == NULL) { 2222 continue; 2223 } 2224 2225 if ((op == KERN_FILE_BYFILE) && 2226 (fp->f_marker == sysctl_file_marker)) { 2227 continue; 2228 } 2229 if (len >= elem_size && elem_count > 0) { 2230 mutex_enter(&fp->f_lock); 2231 fill_file(&kf, fp, ff, i, p->p_pid); 2232 mutex_exit(&fp->f_lock); 2233 mutex_exit(&fd->fd_lock); 2234 error = sysctl_copyout(l, 2235 &kf, dp, out_size); 2236 mutex_enter(&fd->fd_lock); 2237 if (error) 2238 break; 2239 dp += elem_size; 2240 len -= elem_size; 2241 } 2242 if (op == KERN_FILE_BYFILE) 2243 fp->f_marker = sysctl_file_marker; 2244 needed += elem_size; 2245 if (elem_count > 0 && elem_count != INT_MAX) 2246 elem_count--; 2247 } 2248 mutex_exit(&fd->fd_lock); 2249 2250 /* 2251 * Release reference to process. 2252 */ 2253 mutex_enter(proc_lock); 2254 rw_exit(&p->p_reflock); 2255 } 2256 if (op == KERN_FILE_BYFILE) { 2257 sysctl_file_marker++; 2258 2259 /* Reset all markers if wrapped. */ 2260 if (sysctl_file_marker == 0) { 2261 sysctl_file_marker_reset(); 2262 sysctl_file_marker++; 2263 } 2264 } 2265 mutex_exit(proc_lock); 2266 if (op == KERN_FILE_BYFILE) 2267 mutex_exit(&sysctl_file_marker_lock); 2268 sysctl_relock(); 2269 break; 2270 default: 2271 return EINVAL; 2272 } 2273 2274 if (oldp == NULL) 2275 needed += KERN_FILESLOP * elem_size; 2276 *oldlenp = needed; 2277 2278 return error; 2279 } 2280 2281 static void 2282 fill_file(struct kinfo_file *kp, const file_t *fp, const fdfile_t *ff, 2283 int i, pid_t pid) 2284 { 2285 2286 memset(kp, 0, sizeof(*kp)); 2287 2288 kp->ki_fileaddr = PTRTOUINT64(fp); 2289 kp->ki_flag = fp->f_flag; 2290 kp->ki_iflags = 0; 2291 kp->ki_ftype = fp->f_type; 2292 kp->ki_count = fp->f_count; 2293 kp->ki_msgcount = fp->f_msgcount; 2294 kp->ki_fucred = PTRTOUINT64(fp->f_cred); 2295 kp->ki_fuid = kauth_cred_geteuid(fp->f_cred); 2296 kp->ki_fgid = kauth_cred_getegid(fp->f_cred); 2297 kp->ki_fops = PTRTOUINT64(fp->f_ops); 2298 kp->ki_foffset = fp->f_offset; 2299 kp->ki_fdata = PTRTOUINT64(fp->f_data); 2300 2301 /* vnode information to glue this file to something */ 2302 if (fp->f_type == DTYPE_VNODE) { 2303 struct vnode *vp = (struct vnode *)fp->f_data; 2304 2305 kp->ki_vun = PTRTOUINT64(vp->v_un.vu_socket); 2306 kp->ki_vsize = vp->v_size; 2307 kp->ki_vtype = vp->v_type; 2308 kp->ki_vtag = vp->v_tag; 2309 kp->ki_vdata = PTRTOUINT64(vp->v_data); 2310 } 2311 2312 /* process information when retrieved via KERN_FILE_BYPID */ 2313 if (ff != NULL) { 2314 kp->ki_pid = pid; 2315 kp->ki_fd = i; 2316 kp->ki_ofileflags = ff->ff_exclose; 2317 kp->ki_usecount = ff->ff_refcnt; 2318 } 2319 } 2320