1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright 2015, Joyent Inc.
25 */
26
27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
29
30 #include <sys/types.h>
31 #include <sys/sysmacros.h>
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/errno.h>
35 #include <sys/signal.h>
36 #include <sys/cred.h>
37 #include <sys/user.h>
38 #include <sys/conf.h>
39 #include <sys/vfs.h>
40 #include <sys/vnode.h>
41 #include <sys/pathname.h>
42 #include <sys/file.h>
43 #include <sys/flock.h>
44 #include <sys/proc.h>
45 #include <sys/var.h>
46 #include <sys/cpuvar.h>
47 #include <sys/open.h>
48 #include <sys/cmn_err.h>
49 #include <sys/priocntl.h>
50 #include <sys/procset.h>
51 #include <sys/prsystm.h>
52 #include <sys/debug.h>
53 #include <sys/kmem.h>
54 #include <sys/atomic.h>
55 #include <sys/fcntl.h>
56 #include <sys/poll.h>
57 #include <sys/rctl.h>
58 #include <sys/port_impl.h>
59 #include <sys/dtrace.h>
60
61 #include <c2/audit.h>
62 #include <sys/nbmlock.h>
63
64 #ifdef DEBUG
65
66 static uint32_t afd_maxfd; /* # of entries in maximum allocated array */
67 static uint32_t afd_alloc; /* count of kmem_alloc()s */
68 static uint32_t afd_free; /* count of kmem_free()s */
69 static uint32_t afd_wait; /* count of waits on non-zero ref count */
70 #define MAXFD(x) (afd_maxfd = ((afd_maxfd >= (x))? afd_maxfd : (x)))
71 #define COUNT(x) atomic_inc_32(&x)
72
73 #else /* DEBUG */
74
75 #define MAXFD(x)
76 #define COUNT(x)
77
78 #endif /* DEBUG */
79
80 kmem_cache_t *file_cache;
81
82 static void port_close_fd(portfd_t *);
83
84 /*
85 * File descriptor allocation.
86 *
87 * fd_find(fip, minfd) finds the first available descriptor >= minfd.
88 * The most common case is open(2), in which minfd = 0, but we must also
89 * support fcntl(fd, F_DUPFD, minfd).
90 *
91 * The algorithm is as follows: we keep all file descriptors in an infix
92 * binary tree in which each node records the number of descriptors
93 * allocated in its right subtree, including itself. Starting at minfd,
94 * we ascend the tree until we find a non-fully allocated right subtree.
95 * We then descend that subtree in a binary search for the smallest fd.
96 * Finally, we ascend the tree again to increment the allocation count
97 * of every subtree containing the newly-allocated fd. Freeing an fd
98 * requires only the last step: we ascend the tree to decrement allocation
99 * counts. Each of these three steps (ascent to find non-full subtree,
100 * descent to find lowest fd, ascent to update allocation counts) is
101 * O(log n), thus the algorithm as a whole is O(log n).
102 *
103 * We don't implement the fd tree using the customary left/right/parent
104 * pointers, but instead take advantage of the glorious mathematics of
105 * full infix binary trees. For reference, here's an illustration of the
106 * logical structure of such a tree, rooted at 4 (binary 100), covering
107 * the range 1-7 (binary 001-111). Our canonical trees do not include
108 * fd 0; we'll deal with that later.
109 *
110 * 100
111 * / \
112 * / \
113 * 010 110
114 * / \ / \
115 * 001 011 101 111
116 *
117 * We make the following observations, all of which are easily proven by
118 * induction on the depth of the tree:
119 *
120 * (T1) The least-significant bit (LSB) of any node is equal to its level
121 * in the tree. In our example, nodes 001, 011, 101 and 111 are at
122 * level 0; nodes 010 and 110 are at level 1; and node 100 is at level 2.
123 *
124 * (T2) The child size (CSIZE) of node N -- that is, the total number of
125 * right-branch descendants in a child of node N, including itself -- is
126 * given by clearing all but the least significant bit of N. This
127 * follows immediately from (T1). Applying this rule to our example, we
128 * see that CSIZE(100) = 100, CSIZE(x10) = 10, and CSIZE(xx1) = 1.
129 *
130 * (T3) The nearest left ancestor (LPARENT) of node N -- that is, the nearest
131 * ancestor containing node N in its right child -- is given by clearing
132 * the LSB of N. For example, LPARENT(111) = 110 and LPARENT(110) = 100.
133 * Clearing the LSB of nodes 001, 010 or 100 yields zero, reflecting
134 * the fact that these are leftmost nodes. Note that this algorithm
135 * automatically skips generations as necessary. For example, the parent
136 * of node 101 is 110, which is a *right* ancestor (not what we want);
137 * but its grandparent is 100, which is a left ancestor. Clearing the LSB
138 * of 101 gets us to 100 directly, skipping right past the uninteresting
139 * generation (110).
140 *
141 * Note that since LPARENT clears the LSB, whereas CSIZE clears all *but*
142 * the LSB, we can express LPARENT() nicely in terms of CSIZE():
143 *
144 * LPARENT(N) = N - CSIZE(N)
145 *
146 * (T4) The nearest right ancestor (RPARENT) of node N is given by:
147 *
148 * RPARENT(N) = N + CSIZE(N)
149 *
150 * (T5) For every interior node, the children differ from their parent by
151 * CSIZE(parent) / 2. In our example, CSIZE(100) / 2 = 2 = 10 binary,
152 * and indeed, the children of 100 are 100 +/- 10 = 010 and 110.
153 *
154 * Next, we'll need a few two's-complement math tricks. Suppose a number,
155 * N, has the following form:
156 *
157 * N = xxxx10...0
158 *
159 * That is, the binary representation of N consists of some string of bits,
160 * then a 1, then all zeroes. This amounts to nothing more than saying that
161 * N has a least-significant bit, which is true for any N != 0. If we look
162 * at N and N - 1 together, we see that we can combine them in useful ways:
163 *
164 * N = xxxx10...0
165 * N - 1 = xxxx01...1
166 * ------------------------
167 * N & (N - 1) = xxxx000000
168 * N | (N - 1) = xxxx111111
169 * N ^ (N - 1) = 111111
170 *
171 * In particular, this suggests several easy ways to clear all but the LSB,
172 * which by (T2) is exactly what we need to determine CSIZE(N) = 10...0.
173 * We'll opt for this formulation:
174 *
175 * (C1) CSIZE(N) = (N - 1) ^ (N | (N - 1))
176 *
177 * Similarly, we have an easy way to determine LPARENT(N), which requires
178 * that we clear the LSB of N:
179 *
180 * (L1) LPARENT(N) = N & (N - 1)
181 *
182 * We note in the above relations that (N | (N - 1)) - N = CSIZE(N) - 1.
183 * When combined with (T4), this yields an easy way to compute RPARENT(N):
184 *
185 * (R1) RPARENT(N) = (N | (N - 1)) + 1
186 *
187 * Finally, to accommodate fd 0 we must adjust all of our results by +/-1 to
188 * move the fd range from [1, 2^n) to [0, 2^n - 1). This is straightforward,
189 * so there's no need to belabor the algebra; the revised relations become:
190 *
191 * (C1a) CSIZE(N) = N ^ (N | (N + 1))
192 *
193 * (L1a) LPARENT(N) = (N & (N + 1)) - 1
194 *
195 * (R1a) RPARENT(N) = N | (N + 1)
196 *
197 * This completes the mathematical framework. We now have all the tools
198 * we need to implement fd_find() and fd_reserve().
199 *
200 * fd_find(fip, minfd) finds the smallest available file descriptor >= minfd.
201 * It does not actually allocate the descriptor; that's done by fd_reserve().
202 * fd_find() proceeds in two steps:
203 *
204 * (1) Find the leftmost subtree that contains a descriptor >= minfd.
205 * We start at the right subtree rooted at minfd. If this subtree is
206 * not full -- if fip->fi_list[minfd].uf_alloc != CSIZE(minfd) -- then
207 * step 1 is done. Otherwise, we know that all fds in this subtree
208 * are taken, so we ascend to RPARENT(minfd) using (R1a). We repeat
209 * this process until we either find a candidate subtree or exceed
210 * fip->fi_nfiles. We use (C1a) to compute CSIZE().
211 *
212 * (2) Find the smallest fd in the subtree discovered by step 1.
213 * Starting at the root of this subtree, we descend to find the
214 * smallest available fd. Since the left children have the smaller
215 * fds, we will descend rightward only when the left child is full.
216 *
217 * We begin by comparing the number of allocated fds in the root
218 * to the number of allocated fds in its right child; if they differ
219 * by exactly CSIZE(child), we know the left subtree is full, so we
220 * descend right; that is, the right child becomes the search root.
221 * Otherwise we leave the root alone and start following the right
222 * child's left children. As fortune would have it, this is very
223 * simple computationally: by (T5), the right child of fd is just
224 * fd + size, where size = CSIZE(fd) / 2. Applying (T5) again,
225 * we find that the right child's left child is fd + size - (size / 2) =
226 * fd + (size / 2); *its* left child is fd + (size / 2) - (size / 4) =
227 * fd + (size / 4), and so on. In general, fd's right child's
228 * leftmost nth descendant is fd + (size >> n). Thus, to follow
229 * the right child's left descendants, we just halve the size in
230 * each iteration of the search.
231 *
232 * When we descend leftward, we must keep track of the number of fds
233 * that were allocated in all the right subtrees we rejected, so we
234 * know how many of the root fd's allocations are in the remaining
235 * (as yet unexplored) leftmost part of its right subtree. When we
236 * encounter a fully-allocated left child -- that is, when we find
237 * that fip->fi_list[fd].uf_alloc == ralloc + size -- we descend right
238 * (as described earlier), resetting ralloc to zero.
239 *
240 * fd_reserve(fip, fd, incr) either allocates or frees fd, depending
241 * on whether incr is 1 or -1. Starting at fd, fd_reserve() ascends
242 * the leftmost ancestors (see (T3)) and updates the allocation counts.
243 * At each step we use (L1a) to compute LPARENT(), the next left ancestor.
244 *
245 * flist_minsize() finds the minimal tree that still covers all
246 * used fds; as long as the allocation count of a root node is zero, we
247 * don't need that node or its right subtree.
248 *
249 * flist_nalloc() counts the number of allocated fds in the tree, by starting
250 * at the top of the tree and summing the right-subtree allocation counts as
251 * it descends leftwards.
252 *
253 * Note: we assume that flist_grow() will keep fip->fi_nfiles of the form
254 * 2^n - 1. This ensures that the fd trees are always full, which saves
255 * quite a bit of boundary checking.
256 */
257 static int
258 fd_find(uf_info_t *fip, int minfd)
259 {
260 int size, ralloc, fd;
261
262 ASSERT(MUTEX_HELD(&fip->fi_lock));
263 ASSERT((fip->fi_nfiles & (fip->fi_nfiles + 1)) == 0);
264
265 for (fd = minfd; (uint_t)fd < fip->fi_nfiles; fd |= fd + 1) {
266 size = fd ^ (fd | (fd + 1));
267 if (fip->fi_list[fd].uf_alloc == size)
268 continue;
269 for (ralloc = 0, size >>= 1; size != 0; size >>= 1) {
270 ralloc += fip->fi_list[fd + size].uf_alloc;
271 if (fip->fi_list[fd].uf_alloc == ralloc + size) {
272 fd += size;
273 ralloc = 0;
274 }
275 }
276 return (fd);
277 }
278 return (-1);
279 }
280
281 static void
282 fd_reserve(uf_info_t *fip, int fd, int incr)
283 {
284 int pfd;
285 uf_entry_t *ufp = &fip->fi_list[fd];
286
287 ASSERT((uint_t)fd < fip->fi_nfiles);
288 ASSERT((ufp->uf_busy == 0 && incr == 1) ||
289 (ufp->uf_busy == 1 && incr == -1));
290 ASSERT(MUTEX_HELD(&ufp->uf_lock));
291 ASSERT(MUTEX_HELD(&fip->fi_lock));
292
293 for (pfd = fd; pfd >= 0; pfd = (pfd & (pfd + 1)) - 1)
294 fip->fi_list[pfd].uf_alloc += incr;
295
296 ufp->uf_busy += incr;
297 }
298
299 static int
300 flist_minsize(uf_info_t *fip)
301 {
302 int fd;
303
304 /*
305 * We'd like to ASSERT(MUTEX_HELD(&fip->fi_lock)), but we're called
306 * by flist_fork(), which relies on other mechanisms for mutual
307 * exclusion.
308 */
309 ASSERT((fip->fi_nfiles & (fip->fi_nfiles + 1)) == 0);
310
311 for (fd = fip->fi_nfiles; fd != 0; fd >>= 1)
312 if (fip->fi_list[fd >> 1].uf_alloc != 0)
313 break;
314
315 return (fd);
316 }
317
318 static int
319 flist_nalloc(uf_info_t *fip)
320 {
321 int fd;
322 int nalloc = 0;
323
324 ASSERT(MUTEX_HELD(&fip->fi_lock));
325 ASSERT((fip->fi_nfiles & (fip->fi_nfiles + 1)) == 0);
326
327 for (fd = fip->fi_nfiles; fd != 0; fd >>= 1)
328 nalloc += fip->fi_list[fd >> 1].uf_alloc;
329
330 return (nalloc);
331 }
332
333 /*
334 * Increase size of the fi_list array to accommodate at least maxfd.
335 * We keep the size of the form 2^n - 1 for benefit of fd_find().
336 */
337 static void
338 flist_grow(int maxfd)
339 {
340 uf_info_t *fip = P_FINFO(curproc);
341 int newcnt, oldcnt;
342 uf_entry_t *src, *dst, *newlist, *oldlist, *newend, *oldend;
343 uf_rlist_t *urp;
344
345 for (newcnt = 1; newcnt <= maxfd; newcnt = (newcnt << 1) | 1)
346 continue;
347
348 newlist = kmem_zalloc(newcnt * sizeof (uf_entry_t), KM_SLEEP);
349
350 mutex_enter(&fip->fi_lock);
351 oldcnt = fip->fi_nfiles;
352 if (newcnt <= oldcnt) {
353 mutex_exit(&fip->fi_lock);
354 kmem_free(newlist, newcnt * sizeof (uf_entry_t));
355 return;
356 }
357 ASSERT((newcnt & (newcnt + 1)) == 0);
358 oldlist = fip->fi_list;
359 oldend = oldlist + oldcnt;
360 newend = newlist + oldcnt; /* no need to lock beyond old end */
361
362 /*
363 * fi_list and fi_nfiles cannot change while any uf_lock is held,
364 * so we must grab all the old locks *and* the new locks up to oldcnt.
365 * (Locks beyond the end of oldcnt aren't visible until we store
366 * the new fi_nfiles, which is the last thing we do before dropping
367 * all the locks, so there's no need to acquire these locks).
368 * Holding the new locks is necessary because when fi_list changes
369 * to point to the new list, fi_nfiles won't have been stored yet.
370 * If we *didn't* hold the new locks, someone doing a UF_ENTER()
371 * could see the new fi_list, grab the new uf_lock, and then see
372 * fi_nfiles change while the lock is held -- in violation of
373 * UF_ENTER() semantics.
374 */
375 for (src = oldlist; src < oldend; src++)
376 mutex_enter(&src->uf_lock);
377
378 for (dst = newlist; dst < newend; dst++)
379 mutex_enter(&dst->uf_lock);
380
381 for (src = oldlist, dst = newlist; src < oldend; src++, dst++) {
382 dst->uf_file = src->uf_file;
383 dst->uf_fpollinfo = src->uf_fpollinfo;
384 dst->uf_refcnt = src->uf_refcnt;
385 dst->uf_alloc = src->uf_alloc;
386 dst->uf_flag = src->uf_flag;
387 dst->uf_busy = src->uf_busy;
388 dst->uf_portfd = src->uf_portfd;
389 }
390
391 /*
392 * As soon as we store the new flist, future locking operations
393 * will use it. Therefore, we must ensure that all the state
394 * we've just established reaches global visibility before the
395 * new flist does.
396 */
397 membar_producer();
398 fip->fi_list = newlist;
399
400 /*
401 * Routines like getf() make an optimistic check on the validity
402 * of the supplied file descriptor: if it's less than the current
403 * value of fi_nfiles -- examined without any locks -- then it's
404 * safe to attempt a UF_ENTER() on that fd (which is a valid
405 * assumption because fi_nfiles only increases). Therefore, it
406 * is critical that the new value of fi_nfiles not reach global
407 * visibility until after the new fi_list: if it happened the
408 * other way around, getf() could see the new fi_nfiles and attempt
409 * a UF_ENTER() on the old fi_list, which would write beyond its
410 * end if the fd exceeded the old fi_nfiles.
411 */
412 membar_producer();
413 fip->fi_nfiles = newcnt;
414
415 /*
416 * The new state is consistent now, so we can drop all the locks.
417 */
418 for (dst = newlist; dst < newend; dst++)
419 mutex_exit(&dst->uf_lock);
420
421 for (src = oldlist; src < oldend; src++) {
422 /*
423 * If any threads are blocked on the old cvs, wake them.
424 * This will force them to wake up, discover that fi_list
425 * has changed, and go back to sleep on the new cvs.
426 */
427 cv_broadcast(&src->uf_wanted_cv);
428 cv_broadcast(&src->uf_closing_cv);
429 mutex_exit(&src->uf_lock);
430 }
431
432 mutex_exit(&fip->fi_lock);
433
434 /*
435 * Retire the old flist. We can't actually kmem_free() it now
436 * because someone may still have a pointer to it. Instead,
437 * we link it onto a list of retired flists. The new flist
438 * is at least double the size of the previous flist, so the
439 * total size of all retired flists will be less than the size
440 * of the current one (to prove, consider the sum of a geometric
441 * series in powers of 2). exit() frees the retired flists.
442 */
443 urp = kmem_zalloc(sizeof (uf_rlist_t), KM_SLEEP);
444 urp->ur_list = oldlist;
445 urp->ur_nfiles = oldcnt;
446
447 mutex_enter(&fip->fi_lock);
448 urp->ur_next = fip->fi_rlist;
449 fip->fi_rlist = urp;
450 mutex_exit(&fip->fi_lock);
451 }
452
453 /*
454 * Utility functions for keeping track of the active file descriptors.
455 */
456 void
457 clear_stale_fd() /* called from post_syscall() */
458 {
459 afd_t *afd = &curthread->t_activefd;
460 int i;
461
462 /* uninitialized is ok here, a_nfd is then zero */
463 for (i = 0; i < afd->a_nfd; i++) {
464 /* assert that this should not be necessary */
465 ASSERT(afd->a_fd[i] == -1);
466 afd->a_fd[i] = -1;
467 }
468 afd->a_stale = 0;
469 }
470
471 void
472 free_afd(afd_t *afd) /* called below and from thread_free() */
473 {
474 int i;
475
476 /* free the buffer if it was kmem_alloc()ed */
477 if (afd->a_nfd > sizeof (afd->a_buf) / sizeof (afd->a_buf[0])) {
478 COUNT(afd_free);
479 kmem_free(afd->a_fd, afd->a_nfd * sizeof (afd->a_fd[0]));
480 }
481
482 /* (re)initialize the structure */
483 afd->a_fd = &afd->a_buf[0];
484 afd->a_nfd = sizeof (afd->a_buf) / sizeof (afd->a_buf[0]);
485 afd->a_stale = 0;
486 for (i = 0; i < afd->a_nfd; i++)
487 afd->a_fd[i] = -1;
488 }
489
490 static void
491 set_active_fd(int fd)
492 {
493 afd_t *afd = &curthread->t_activefd;
494 int i;
495 int *old_fd;
496 int old_nfd;
497 int *new_fd;
498 int new_nfd;
499
500 if (afd->a_nfd == 0) { /* first time initialization */
501 ASSERT(fd == -1);
502 mutex_enter(&afd->a_fdlock);
503 free_afd(afd);
504 mutex_exit(&afd->a_fdlock);
505 }
506
507 /* insert fd into vacant slot, if any */
508 for (i = 0; i < afd->a_nfd; i++) {
509 if (afd->a_fd[i] == -1) {
510 afd->a_fd[i] = fd;
511 return;
512 }
513 }
514
515 /*
516 * Reallocate the a_fd[] array to add one more slot.
517 */
518 ASSERT(fd == -1);
519 old_nfd = afd->a_nfd;
520 old_fd = afd->a_fd;
521 new_nfd = old_nfd + 1;
522 new_fd = kmem_alloc(new_nfd * sizeof (afd->a_fd[0]), KM_SLEEP);
523 MAXFD(new_nfd);
524 COUNT(afd_alloc);
525
526 mutex_enter(&afd->a_fdlock);
527 afd->a_fd = new_fd;
528 afd->a_nfd = new_nfd;
529 for (i = 0; i < old_nfd; i++)
530 afd->a_fd[i] = old_fd[i];
531 afd->a_fd[i] = fd;
532 mutex_exit(&afd->a_fdlock);
533
534 if (old_nfd > sizeof (afd->a_buf) / sizeof (afd->a_buf[0])) {
535 COUNT(afd_free);
536 kmem_free(old_fd, old_nfd * sizeof (afd->a_fd[0]));
537 }
538 }
539
540 void
541 clear_active_fd(int fd) /* called below and from aio.c */
542 {
543 afd_t *afd = &curthread->t_activefd;
544 int i;
545
546 for (i = 0; i < afd->a_nfd; i++) {
547 if (afd->a_fd[i] == fd) {
548 afd->a_fd[i] = -1;
549 break;
550 }
551 }
552 ASSERT(i < afd->a_nfd); /* not found is not ok */
553 }
554
555 /*
556 * Does this thread have this fd active?
557 */
558 static int
559 is_active_fd(kthread_t *t, int fd)
560 {
561 afd_t *afd = &t->t_activefd;
562 int i;
563
564 ASSERT(t != curthread);
565 mutex_enter(&afd->a_fdlock);
566 /* uninitialized is ok here, a_nfd is then zero */
567 for (i = 0; i < afd->a_nfd; i++) {
568 if (afd->a_fd[i] == fd) {
569 mutex_exit(&afd->a_fdlock);
570 return (1);
571 }
572 }
573 mutex_exit(&afd->a_fdlock);
574 return (0);
575 }
576
577 /*
578 * Convert a user supplied file descriptor into a pointer to a file
579 * structure. Only task is to check range of the descriptor (soft
580 * resource limit was enforced at open time and shouldn't be checked
581 * here).
582 */
583 file_t *
584 getf(int fd)
585 {
586 uf_info_t *fip = P_FINFO(curproc);
587 uf_entry_t *ufp;
588 file_t *fp;
589
590 if ((uint_t)fd >= fip->fi_nfiles)
591 return (NULL);
592
593 /*
594 * Reserve a slot in the active fd array now so we can call
595 * set_active_fd(fd) for real below, while still inside UF_ENTER().
596 */
597 set_active_fd(-1);
598
599 UF_ENTER(ufp, fip, fd);
600
601 if ((fp = ufp->uf_file) == NULL) {
602 UF_EXIT(ufp);
603
604 if (fd == fip->fi_badfd && fip->fi_action > 0)
605 tsignal(curthread, fip->fi_action);
606
607 return (NULL);
608 }
609 ufp->uf_refcnt++;
610
611 set_active_fd(fd); /* record the active file descriptor */
612
613 UF_EXIT(ufp);
614
615 return (fp);
616 }
617
618 /*
619 * Close whatever file currently occupies the file descriptor slot
620 * and install the new file, usually NULL, in the file descriptor slot.
621 * The close must complete before we release the file descriptor slot.
622 * If newfp != NULL we only return an error if we can't allocate the
623 * slot so the caller knows that it needs to free the filep;
624 * in the other cases we return the error number from closef().
625 */
626 int
627 closeandsetf(int fd, file_t *newfp)
628 {
629 proc_t *p = curproc;
630 uf_info_t *fip = P_FINFO(p);
631 uf_entry_t *ufp;
632 file_t *fp;
633 fpollinfo_t *fpip;
634 portfd_t *pfd;
635 int error;
636
637 if ((uint_t)fd >= fip->fi_nfiles) {
638 if (newfp == NULL)
639 return (EBADF);
640 flist_grow(fd);
641 }
642
643 if (newfp != NULL) {
644 /*
645 * If ufp is reserved but has no file pointer, it's in the
646 * transition between ufalloc() and setf(). We must wait
647 * for this transition to complete before assigning the
648 * new non-NULL file pointer.
649 */
650 mutex_enter(&fip->fi_lock);
651 if (fd == fip->fi_badfd) {
652 mutex_exit(&fip->fi_lock);
653 if (fip->fi_action > 0)
654 tsignal(curthread, fip->fi_action);
655 return (EBADF);
656 }
657 UF_ENTER(ufp, fip, fd);
658 while (ufp->uf_busy && ufp->uf_file == NULL) {
659 mutex_exit(&fip->fi_lock);
660 cv_wait_stop(&ufp->uf_wanted_cv, &ufp->uf_lock, 250);
661 UF_EXIT(ufp);
662 mutex_enter(&fip->fi_lock);
663 UF_ENTER(ufp, fip, fd);
664 }
665 if ((fp = ufp->uf_file) == NULL) {
666 ASSERT(ufp->uf_fpollinfo == NULL);
667 ASSERT(ufp->uf_flag == 0);
668 fd_reserve(fip, fd, 1);
669 ufp->uf_file = newfp;
670 UF_EXIT(ufp);
671 mutex_exit(&fip->fi_lock);
672 return (0);
673 }
674 mutex_exit(&fip->fi_lock);
675 } else {
676 UF_ENTER(ufp, fip, fd);
677 if ((fp = ufp->uf_file) == NULL) {
678 UF_EXIT(ufp);
679 return (EBADF);
680 }
681 }
682
683 ASSERT(ufp->uf_busy);
684 ufp->uf_file = NULL;
685 ufp->uf_flag = 0;
686
687 /*
688 * If the file descriptor reference count is non-zero, then
689 * some other lwp in the process is performing system call
690 * activity on the file. To avoid blocking here for a long
691 * time (the other lwp might be in a long term sleep in its
692 * system call), we scan all other lwps in the process to
693 * find the ones with this fd as one of their active fds,
694 * set their a_stale flag, and set them running if they
695 * are in an interruptible sleep so they will emerge from
696 * their system calls immediately. post_syscall() will
697 * test the a_stale flag and set errno to EBADF.
698 */
699 ASSERT(ufp->uf_refcnt == 0 || p->p_lwpcnt > 1);
700 if (ufp->uf_refcnt > 0) {
701 kthread_t *t;
702
703 /*
704 * We call sprlock_proc(p) to ensure that the thread
705 * list will not change while we are scanning it.
706 * To do this, we must drop ufp->uf_lock and then
707 * reacquire it (so we are not holding both p->p_lock
708 * and ufp->uf_lock at the same time). ufp->uf_lock
709 * must be held for is_active_fd() to be correct
710 * (set_active_fd() is called while holding ufp->uf_lock).
711 *
712 * This is a convoluted dance, but it is better than
713 * the old brute-force method of stopping every thread
714 * in the process by calling holdlwps(SHOLDFORK1).
715 */
716
717 UF_EXIT(ufp);
718 COUNT(afd_wait);
719
720 mutex_enter(&p->p_lock);
721 sprlock_proc(p);
722 mutex_exit(&p->p_lock);
723
724 UF_ENTER(ufp, fip, fd);
725 ASSERT(ufp->uf_file == NULL);
726
727 if (ufp->uf_refcnt > 0) {
728 for (t = curthread->t_forw;
729 t != curthread;
730 t = t->t_forw) {
731 if (is_active_fd(t, fd)) {
732 thread_lock(t);
733 t->t_activefd.a_stale = 1;
734 t->t_post_sys = 1;
735 if (ISWAKEABLE(t))
736 setrun_locked(t);
737 thread_unlock(t);
738 }
739 }
740 }
741
742 UF_EXIT(ufp);
743
744 mutex_enter(&p->p_lock);
745 sprunlock(p);
746
747 UF_ENTER(ufp, fip, fd);
748 ASSERT(ufp->uf_file == NULL);
749 }
750
751 /*
752 * Wait for other lwps to stop using this file descriptor.
753 */
754 while (ufp->uf_refcnt > 0) {
755 cv_wait_stop(&ufp->uf_closing_cv, &ufp->uf_lock, 250);
756 /*
757 * cv_wait_stop() drops ufp->uf_lock, so the file list
758 * can change. Drop the lock on our (possibly) stale
759 * ufp and let UF_ENTER() find and lock the current ufp.
760 */
761 UF_EXIT(ufp);
762 UF_ENTER(ufp, fip, fd);
763 }
764
765 #ifdef DEBUG
766 /*
767 * catch a watchfd on device's pollhead list but not on fpollinfo list
768 */
769 if (ufp->uf_fpollinfo != NULL)
770 checkwfdlist(fp->f_vnode, ufp->uf_fpollinfo);
771 #endif /* DEBUG */
772
773 /*
774 * We may need to cleanup some cached poll states in t_pollstate
775 * before the fd can be reused. It is important that we don't
776 * access a stale thread structure. We will do the cleanup in two
777 * phases to avoid deadlock and holding uf_lock for too long.
778 * In phase 1, hold the uf_lock and call pollblockexit() to set
779 * state in t_pollstate struct so that a thread does not exit on
780 * us. In phase 2, we drop the uf_lock and call pollcacheclean().
781 */
782 pfd = ufp->uf_portfd;
783 ufp->uf_portfd = NULL;
784 fpip = ufp->uf_fpollinfo;
785 ufp->uf_fpollinfo = NULL;
786 if (fpip != NULL)
787 pollblockexit(fpip);
788 UF_EXIT(ufp);
789 if (fpip != NULL)
790 pollcacheclean(fpip, fd);
791 if (pfd)
792 port_close_fd(pfd);
793
794 /*
795 * Keep the file descriptor entry reserved across the closef().
796 */
797 error = closef(fp);
798
799 setf(fd, newfp);
800
801 /* Only return closef() error when closing is all we do */
802 return (newfp == NULL ? error : 0);
803 }
804
805 /*
806 * Decrement uf_refcnt; wakeup anyone waiting to close the file.
807 */
808 void
809 releasef(int fd)
810 {
811 uf_info_t *fip = P_FINFO(curproc);
812 uf_entry_t *ufp;
813
814 UF_ENTER(ufp, fip, fd);
815 ASSERT(ufp->uf_refcnt > 0);
816 clear_active_fd(fd); /* clear the active file descriptor */
817 if (--ufp->uf_refcnt == 0)
818 cv_broadcast(&ufp->uf_closing_cv);
819 UF_EXIT(ufp);
820 }
821
822 /*
823 * Identical to releasef() but can be called from another process.
824 */
825 void
826 areleasef(int fd, uf_info_t *fip)
827 {
828 uf_entry_t *ufp;
829
830 UF_ENTER(ufp, fip, fd);
831 ASSERT(ufp->uf_refcnt > 0);
832 if (--ufp->uf_refcnt == 0)
833 cv_broadcast(&ufp->uf_closing_cv);
834 UF_EXIT(ufp);
835 }
836
837 /*
838 * Duplicate all file descriptors across a fork.
839 */
840 void
841 flist_fork(proc_t *pp, proc_t *cp)
842 {
843 int fd, nfiles;
844 uf_entry_t *pufp, *cufp;
845
846 uf_info_t *pfip = P_FINFO(pp);
847 uf_info_t *cfip = P_FINFO(cp);
848
849 mutex_init(&cfip->fi_lock, NULL, MUTEX_DEFAULT, NULL);
850 cfip->fi_rlist = NULL;
851
852 /*
853 * We don't need to hold fi_lock because all other lwp's in the
854 * parent have been held.
855 */
856 cfip->fi_nfiles = nfiles = flist_minsize(pfip);
857
858 cfip->fi_list = kmem_zalloc(nfiles * sizeof (uf_entry_t), KM_SLEEP);
859
860 for (fd = 0, pufp = pfip->fi_list, cufp = cfip->fi_list; fd < nfiles;
861 fd++, pufp++, cufp++) {
862 cufp->uf_file = pufp->uf_file;
863 cufp->uf_alloc = pufp->uf_alloc;
864 cufp->uf_flag = pufp->uf_flag;
865 cufp->uf_busy = pufp->uf_busy;
866
867 if (cufp->uf_file != NULL && cufp->uf_file->f_vnode != NULL) {
868 (void) VOP_IOCTL(cufp->uf_file->f_vnode, F_ASSOCI_PID,
869 (intptr_t)cp->p_pidp->pid_id, FKIOCTL, kcred,
870 NULL, NULL);
871 }
872
873 if (pufp->uf_file == NULL) {
874 ASSERT(pufp->uf_flag == 0);
875 if (pufp->uf_busy) {
876 /*
877 * Grab locks to appease ASSERTs in fd_reserve
878 */
879 mutex_enter(&cfip->fi_lock);
880 mutex_enter(&cufp->uf_lock);
881 fd_reserve(cfip, fd, -1);
882 mutex_exit(&cufp->uf_lock);
883 mutex_exit(&cfip->fi_lock);
884 }
885 }
886 }
887 }
888
889 /*
890 * Close all open file descriptors for the current process.
891 * This is only called from exit(), which is single-threaded,
892 * so we don't need any locking.
893 */
894 void
895 closeall(uf_info_t *fip)
896 {
897 int fd;
898 file_t *fp;
899 uf_entry_t *ufp;
900
901 ufp = fip->fi_list;
902 for (fd = 0; fd < fip->fi_nfiles; fd++, ufp++) {
903 if ((fp = ufp->uf_file) != NULL) {
904 ufp->uf_file = NULL;
905 if (ufp->uf_portfd != NULL) {
906 portfd_t *pfd;
907 /* remove event port association */
908 pfd = ufp->uf_portfd;
909 ufp->uf_portfd = NULL;
910 port_close_fd(pfd);
911 }
912 ASSERT(ufp->uf_fpollinfo == NULL);
913 (void) closef(fp);
914 }
915 }
916
917 kmem_free(fip->fi_list, fip->fi_nfiles * sizeof (uf_entry_t));
918 fip->fi_list = NULL;
919 fip->fi_nfiles = 0;
920 while (fip->fi_rlist != NULL) {
921 uf_rlist_t *urp = fip->fi_rlist;
922 fip->fi_rlist = urp->ur_next;
923 kmem_free(urp->ur_list, urp->ur_nfiles * sizeof (uf_entry_t));
924 kmem_free(urp, sizeof (uf_rlist_t));
925 }
926 }
927
928 /*
929 * Internal form of close. Decrement reference count on file
930 * structure. Decrement reference count on the vnode following
931 * removal of the referencing file structure.
932 */
933 int
934 closef(file_t *fp)
935 {
936 vnode_t *vp;
937 int error;
938 int count;
939 int flag;
940 offset_t offset;
941
942 /*
943 * audit close of file (may be exit)
944 */
945 if (AU_AUDITING())
946 audit_closef(fp);
947 ASSERT(MUTEX_NOT_HELD(&P_FINFO(curproc)->fi_lock));
948
949 mutex_enter(&fp->f_tlock);
950
951 ASSERT(fp->f_count > 0);
952
953 count = fp->f_count--;
954 flag = fp->f_flag;
955 offset = fp->f_offset;
956
957 vp = fp->f_vnode;
958 if (vp != NULL) {
959 (void) VOP_IOCTL(vp, F_DASSOC_PID,
960 (intptr_t)(ttoproc(curthread)->p_pidp->pid_id), FKIOCTL,
961 kcred, NULL, NULL);
962 }
963
964 error = VOP_CLOSE(vp, flag, count, offset, fp->f_cred, NULL);
965
966 if (count > 1) {
967 mutex_exit(&fp->f_tlock);
968 return (error);
969 }
970 ASSERT(fp->f_count == 0);
971 /* Last reference, remove any OFD style lock for the file_t */
972 ofdcleanlock(fp);
973 mutex_exit(&fp->f_tlock);
974
975 /*
976 * If DTrace has getf() subroutines active, it will set dtrace_closef
977 * to point to code that implements a barrier with respect to probe
978 * context. This must be called before the file_t is freed (and the
979 * vnode that it refers to is released) -- but it must be after the
980 * file_t has been removed from the uf_entry_t. That is, there must
981 * be no way for a racing getf() in probe context to yield the fp that
982 * we're operating upon.
983 */
984 if (dtrace_closef != NULL)
985 (*dtrace_closef)();
986
987 VN_RELE(vp);
988 /*
989 * deallocate resources to audit_data
990 */
991 if (audit_active)
992 audit_unfalloc(fp);
993 crfree(fp->f_cred);
994 kmem_cache_free(file_cache, fp);
995 return (error);
996 }
997
998 /*
999 * This is a combination of ufalloc() and setf().
1000 */
1001 int
1002 ufalloc_file(int start, file_t *fp)
1003 {
1004 proc_t *p = curproc;
1005 uf_info_t *fip = P_FINFO(p);
1006 int filelimit;
1007 uf_entry_t *ufp;
1008 int nfiles;
1009 int fd;
1010
1011 /*
1012 * Assertion is to convince the correctness of the following
1013 * assignment for filelimit after casting to int.
1014 */
1015 ASSERT(p->p_fno_ctl <= INT_MAX);
1016 filelimit = (int)p->p_fno_ctl;
1017
1018 for (;;) {
1019 mutex_enter(&fip->fi_lock);
1020 fd = fd_find(fip, start);
1021 if (fd >= 0 && fd == fip->fi_badfd) {
1022 start = fd + 1;
1023 mutex_exit(&fip->fi_lock);
1024 continue;
1025 }
1026 if ((uint_t)fd < filelimit)
1027 break;
1028 if (fd >= filelimit) {
1029 mutex_exit(&fip->fi_lock);
1030 mutex_enter(&p->p_lock);
1031 (void) rctl_action(rctlproc_legacy[RLIMIT_NOFILE],
1032 p->p_rctls, p, RCA_SAFE);
1033 mutex_exit(&p->p_lock);
1034 return (-1);
1035 }
1036 /* fd_find() returned -1 */
1037 nfiles = fip->fi_nfiles;
1038 mutex_exit(&fip->fi_lock);
1039 flist_grow(MAX(start, nfiles));
1040 }
1041
1042 UF_ENTER(ufp, fip, fd);
1043 fd_reserve(fip, fd, 1);
1044 ASSERT(ufp->uf_file == NULL);
1045 ufp->uf_file = fp;
1046 UF_EXIT(ufp);
1047 mutex_exit(&fip->fi_lock);
1048 return (fd);
1049 }
1050
1051 /*
1052 * Allocate a user file descriptor greater than or equal to "start".
1053 */
1054 int
1055 ufalloc(int start)
1056 {
1057 return (ufalloc_file(start, NULL));
1058 }
1059
1060 /*
1061 * Check that a future allocation of count fds on proc p has a good
1062 * chance of succeeding. If not, do rctl processing as if we'd failed
1063 * the allocation.
1064 *
1065 * Our caller must guarantee that p cannot disappear underneath us.
1066 */
1067 int
1068 ufcanalloc(proc_t *p, uint_t count)
1069 {
1070 uf_info_t *fip = P_FINFO(p);
1071 int filelimit;
1072 int current;
1073
1074 if (count == 0)
1075 return (1);
1076
1077 ASSERT(p->p_fno_ctl <= INT_MAX);
1078 filelimit = (int)p->p_fno_ctl;
1079
1080 mutex_enter(&fip->fi_lock);
1081 current = flist_nalloc(fip); /* # of in-use descriptors */
1082 mutex_exit(&fip->fi_lock);
1083
1084 /*
1085 * If count is a positive integer, the worst that can happen is
1086 * an overflow to a negative value, which is caught by the >= 0 check.
1087 */
1088 current += count;
1089 if (count <= INT_MAX && current >= 0 && current <= filelimit)
1090 return (1);
1091
1092 mutex_enter(&p->p_lock);
1093 (void) rctl_action(rctlproc_legacy[RLIMIT_NOFILE],
1094 p->p_rctls, p, RCA_SAFE);
1095 mutex_exit(&p->p_lock);
1096 return (0);
1097 }
1098
1099 /*
1100 * Allocate a user file descriptor and a file structure.
1101 * Initialize the descriptor to point at the file structure.
1102 * If fdp is NULL, the user file descriptor will not be allocated.
1103 */
1104 int
1105 falloc(vnode_t *vp, int flag, file_t **fpp, int *fdp)
1106 {
1107 file_t *fp;
1108 int fd;
1109
1110 if (fdp) {
1111 if ((fd = ufalloc(0)) == -1)
1112 return (EMFILE);
1113 }
1114 fp = kmem_cache_alloc(file_cache, KM_SLEEP);
1115 /*
1116 * Note: falloc returns the fp locked
1117 */
1118 mutex_enter(&fp->f_tlock);
1119 fp->f_count = 1;
1120 fp->f_flag = (ushort_t)flag;
1121 fp->f_flag2 = (flag & (FSEARCH|FEXEC)) >> 16;
1122 fp->f_vnode = vp;
1123 fp->f_offset = 0;
1124 fp->f_audit_data = 0;
1125 crhold(fp->f_cred = CRED());
1126 /*
1127 * allocate resources to audit_data
1128 */
1129 if (audit_active)
1130 audit_falloc(fp);
1131 *fpp = fp;
1132 if (fdp)
1133 *fdp = fd;
1134 return (0);
1135 }
1136
1137 /*ARGSUSED*/
1138 static int
1139 file_cache_constructor(void *buf, void *cdrarg, int kmflags)
1140 {
1141 file_t *fp = buf;
1142
1143 mutex_init(&fp->f_tlock, NULL, MUTEX_DEFAULT, NULL);
1144 return (0);
1145 }
1146
1147 /*ARGSUSED*/
1148 static void
1149 file_cache_destructor(void *buf, void *cdrarg)
1150 {
1151 file_t *fp = buf;
1152
1153 mutex_destroy(&fp->f_tlock);
1154 }
1155
1156 void
1157 finit()
1158 {
1159 file_cache = kmem_cache_create("file_cache", sizeof (file_t), 0,
1160 file_cache_constructor, file_cache_destructor, NULL, NULL, NULL, 0);
1161 }
1162
1163 void
1164 unfalloc(file_t *fp)
1165 {
1166 ASSERT(MUTEX_HELD(&fp->f_tlock));
1167 if (--fp->f_count <= 0) {
1168 /*
1169 * deallocate resources to audit_data
1170 */
1171 if (audit_active)
1172 audit_unfalloc(fp);
1173 crfree(fp->f_cred);
1174 mutex_exit(&fp->f_tlock);
1175 kmem_cache_free(file_cache, fp);
1176 } else
1177 mutex_exit(&fp->f_tlock);
1178 }
1179
1180 /*
1181 * Given a file descriptor, set the user's
1182 * file pointer to the given parameter.
1183 */
1184 void
1185 setf(int fd, file_t *fp)
1186 {
1187 uf_info_t *fip = P_FINFO(curproc);
1188 uf_entry_t *ufp;
1189
1190 if (AU_AUDITING())
1191 audit_setf(fp, fd);
1192
1193 if (fp == NULL) {
1194 mutex_enter(&fip->fi_lock);
1195 UF_ENTER(ufp, fip, fd);
1196 fd_reserve(fip, fd, -1);
1197 mutex_exit(&fip->fi_lock);
1198 } else {
1199 UF_ENTER(ufp, fip, fd);
1200 ASSERT(ufp->uf_busy);
1201 }
1202 ASSERT(ufp->uf_fpollinfo == NULL);
1203 ASSERT(ufp->uf_flag == 0);
1204 ufp->uf_file = fp;
1205 cv_broadcast(&ufp->uf_wanted_cv);
1206 UF_EXIT(ufp);
1207 }
1208
1209 /*
1210 * Given a file descriptor, return the file table flags, plus,
1211 * if this is a socket in asynchronous mode, the FASYNC flag.
1212 * getf() may or may not have been called before calling f_getfl().
1213 */
1214 int
1215 f_getfl(int fd, int *flagp)
1216 {
1217 uf_info_t *fip = P_FINFO(curproc);
1218 uf_entry_t *ufp;
1219 file_t *fp;
1220 int error;
1221
1222 if ((uint_t)fd >= fip->fi_nfiles)
1223 error = EBADF;
1224 else {
1225 UF_ENTER(ufp, fip, fd);
1226 if ((fp = ufp->uf_file) == NULL)
1227 error = EBADF;
1228 else {
1229 vnode_t *vp = fp->f_vnode;
1230 int flag = fp->f_flag |
1231 ((fp->f_flag2 & ~FEPOLLED) << 16);
1232
1233 /*
1234 * BSD fcntl() FASYNC compatibility.
1235 */
1236 if (vp->v_type == VSOCK)
1237 flag |= sock_getfasync(vp);
1238 *flagp = flag;
1239 error = 0;
1240 }
1241 UF_EXIT(ufp);
1242 }
1243
1244 return (error);
1245 }
1246
1247 /*
1248 * Given a file descriptor, return the user's file flags.
1249 * Force the FD_CLOEXEC flag for writable self-open /proc files.
1250 * getf() may or may not have been called before calling f_getfd_error().
1251 */
1252 int
1253 f_getfd_error(int fd, int *flagp)
1254 {
1255 uf_info_t *fip = P_FINFO(curproc);
1256 uf_entry_t *ufp;
1257 file_t *fp;
1258 int flag;
1259 int error;
1260
1261 if ((uint_t)fd >= fip->fi_nfiles)
1262 error = EBADF;
1263 else {
1264 UF_ENTER(ufp, fip, fd);
1265 if ((fp = ufp->uf_file) == NULL)
1266 error = EBADF;
1267 else {
1268 flag = ufp->uf_flag;
1269 if ((fp->f_flag & FWRITE) && pr_isself(fp->f_vnode))
1270 flag |= FD_CLOEXEC;
1271 *flagp = flag;
1272 error = 0;
1273 }
1274 UF_EXIT(ufp);
1275 }
1276
1277 return (error);
1278 }
1279
1280 /*
1281 * getf() must have been called before calling f_getfd().
1282 */
1283 char
1284 f_getfd(int fd)
1285 {
1286 int flag = 0;
1287 (void) f_getfd_error(fd, &flag);
1288 return ((char)flag);
1289 }
1290
1291 /*
1292 * Given a file descriptor and file flags, set the user's file flags.
1293 * At present, the only valid flag is FD_CLOEXEC.
1294 * getf() may or may not have been called before calling f_setfd_error().
1295 */
1296 int
1297 f_setfd_error(int fd, int flags)
1298 {
1299 uf_info_t *fip = P_FINFO(curproc);
1300 uf_entry_t *ufp;
1301 int error;
1302
1303 if ((uint_t)fd >= fip->fi_nfiles)
1304 error = EBADF;
1305 else {
1306 UF_ENTER(ufp, fip, fd);
1307 if (ufp->uf_file == NULL)
1308 error = EBADF;
1309 else {
1310 ufp->uf_flag = flags & FD_CLOEXEC;
1311 error = 0;
1312 }
1313 UF_EXIT(ufp);
1314 }
1315 return (error);
1316 }
1317
1318 void
1319 f_setfd(int fd, char flags)
1320 {
1321 (void) f_setfd_error(fd, flags);
1322 }
1323
1324 #define BADFD_MIN 3
1325 #define BADFD_MAX 255
1326
1327 /*
1328 * Attempt to allocate a file descriptor which is bad and which
1329 * is "poison" to the application. It cannot be closed (except
1330 * on exec), allocated for a different use, etc.
1331 */
1332 int
1333 f_badfd(int start, int *fdp, int action)
1334 {
1335 int fdr;
1336 int badfd;
1337 uf_info_t *fip = P_FINFO(curproc);
1338
1339 #ifdef _LP64
1340 /* No restrictions on 64 bit _file */
1341 if (get_udatamodel() != DATAMODEL_ILP32)
1342 return (EINVAL);
1343 #endif
1344
1345 if (start > BADFD_MAX || start < BADFD_MIN)
1346 return (EINVAL);
1347
1348 if (action >= NSIG || action < 0)
1349 return (EINVAL);
1350
1351 mutex_enter(&fip->fi_lock);
1352 badfd = fip->fi_badfd;
1353 mutex_exit(&fip->fi_lock);
1354
1355 if (badfd != -1)
1356 return (EAGAIN);
1357
1358 fdr = ufalloc(start);
1359
1360 if (fdr > BADFD_MAX) {
1361 setf(fdr, NULL);
1362 return (EMFILE);
1363 }
1364 if (fdr < 0)
1365 return (EMFILE);
1366
1367 mutex_enter(&fip->fi_lock);
1368 if (fip->fi_badfd != -1) {
1369 /* Lost race */
1370 mutex_exit(&fip->fi_lock);
1371 setf(fdr, NULL);
1372 return (EAGAIN);
1373 }
1374 fip->fi_action = action;
1375 fip->fi_badfd = fdr;
1376 mutex_exit(&fip->fi_lock);
1377 setf(fdr, NULL);
1378
1379 *fdp = fdr;
1380
1381 return (0);
1382 }
1383
1384 /*
1385 * Allocate a file descriptor and assign it to the vnode "*vpp",
1386 * performing the usual open protocol upon it and returning the
1387 * file descriptor allocated. It is the responsibility of the
1388 * caller to dispose of "*vpp" if any error occurs.
1389 */
1390 int
1391 fassign(vnode_t **vpp, int mode, int *fdp)
1392 {
1393 file_t *fp;
1394 int error;
1395 int fd;
1396
1397 if (error = falloc((vnode_t *)NULL, mode, &fp, &fd))
1398 return (error);
1399 if (error = VOP_OPEN(vpp, mode, fp->f_cred, NULL)) {
1400 setf(fd, NULL);
1401 unfalloc(fp);
1402 return (error);
1403 }
1404 fp->f_vnode = *vpp;
1405 mutex_exit(&fp->f_tlock);
1406 /*
1407 * Fill in the slot falloc reserved.
1408 */
1409 setf(fd, fp);
1410 *fdp = fd;
1411 return (0);
1412 }
1413
1414 /*
1415 * When a process forks it must increment the f_count of all file pointers
1416 * since there is a new process pointing at them. fcnt_add(fip, 1) does this.
1417 * Since we are called when there is only 1 active lwp we don't need to
1418 * hold fi_lock or any uf_lock. If the fork fails, fork_fail() calls
1419 * fcnt_add(fip, -1) to restore the counts.
1420 */
1421 void
1422 fcnt_add(uf_info_t *fip, int incr)
1423 {
1424 int i;
1425 uf_entry_t *ufp;
1426 file_t *fp;
1427
1428 ufp = fip->fi_list;
1429 for (i = 0; i < fip->fi_nfiles; i++, ufp++) {
1430 if ((fp = ufp->uf_file) != NULL) {
1431 mutex_enter(&fp->f_tlock);
1432 ASSERT((incr == 1 && fp->f_count >= 1) ||
1433 (incr == -1 && fp->f_count >= 2));
1434 fp->f_count += incr;
1435 mutex_exit(&fp->f_tlock);
1436 }
1437 }
1438 }
1439
1440 /*
1441 * This is called from exec to close all fd's that have the FD_CLOEXEC flag
1442 * set and also to close all self-open for write /proc file descriptors.
1443 */
1444 void
1445 close_exec(uf_info_t *fip)
1446 {
1447 int fd;
1448 file_t *fp;
1449 fpollinfo_t *fpip;
1450 uf_entry_t *ufp;
1451 portfd_t *pfd;
1452
1453 ufp = fip->fi_list;
1454 for (fd = 0; fd < fip->fi_nfiles; fd++, ufp++) {
1455 if ((fp = ufp->uf_file) != NULL &&
1456 ((ufp->uf_flag & FD_CLOEXEC) ||
1457 ((fp->f_flag & FWRITE) && pr_isself(fp->f_vnode)))) {
1458 fpip = ufp->uf_fpollinfo;
1459 mutex_enter(&fip->fi_lock);
1460 mutex_enter(&ufp->uf_lock);
1461 fd_reserve(fip, fd, -1);
1462 mutex_exit(&fip->fi_lock);
1463 ufp->uf_file = NULL;
1464 ufp->uf_fpollinfo = NULL;
1465 ufp->uf_flag = 0;
1466 /*
1467 * We may need to cleanup some cached poll states
1468 * in t_pollstate before the fd can be reused. It
1469 * is important that we don't access a stale thread
1470 * structure. We will do the cleanup in two
1471 * phases to avoid deadlock and holding uf_lock for
1472 * too long. In phase 1, hold the uf_lock and call
1473 * pollblockexit() to set state in t_pollstate struct
1474 * so that a thread does not exit on us. In phase 2,
1475 * we drop the uf_lock and call pollcacheclean().
1476 */
1477 pfd = ufp->uf_portfd;
1478 ufp->uf_portfd = NULL;
1479 if (fpip != NULL)
1480 pollblockexit(fpip);
1481 mutex_exit(&ufp->uf_lock);
1482 if (fpip != NULL)
1483 pollcacheclean(fpip, fd);
1484 if (pfd)
1485 port_close_fd(pfd);
1486 (void) closef(fp);
1487 }
1488 }
1489
1490 /* Reset bad fd */
1491 fip->fi_badfd = -1;
1492 fip->fi_action = -1;
1493 }
1494
1495 /*
1496 * Utility function called by most of the *at() system call interfaces.
1497 *
1498 * Generate a starting vnode pointer for an (fd, path) pair where 'fd'
1499 * is an open file descriptor for a directory to be used as the starting
1500 * point for the lookup of the relative pathname 'path' (or, if path is
1501 * NULL, generate a vnode pointer for the direct target of the operation).
1502 *
1503 * If we successfully return a non-NULL startvp, it has been the target
1504 * of VN_HOLD() and the caller must call VN_RELE() on it.
1505 */
1506 int
1507 fgetstartvp(int fd, char *path, vnode_t **startvpp)
1508 {
1509 vnode_t *startvp;
1510 file_t *startfp;
1511 char startchar;
1512
1513 if (fd == AT_FDCWD && path == NULL)
1514 return (EFAULT);
1515
1516 if (fd == AT_FDCWD) {
1517 /*
1518 * Start from the current working directory.
1519 */
1520 startvp = NULL;
1521 } else {
1522 if (path == NULL)
1523 startchar = '\0';
1524 else if (copyin(path, &startchar, sizeof (char)))
1525 return (EFAULT);
1526
1527 if (startchar == '/') {
1528 /*
1529 * 'path' is an absolute pathname.
1530 */
1531 startvp = NULL;
1532 } else {
1533 /*
1534 * 'path' is a relative pathname or we will
1535 * be applying the operation to 'fd' itself.
1536 */
1537 if ((startfp = getf(fd)) == NULL)
1538 return (EBADF);
1539 startvp = startfp->f_vnode;
1540 VN_HOLD(startvp);
1541 releasef(fd);
1542 }
1543 }
1544 *startvpp = startvp;
1545 return (0);
1546 }
1547
1548 /*
1549 * Called from fchownat() and fchmodat() to set ownership and mode.
1550 * The contents of *vap must be set before calling here.
1551 */
1552 int
1553 fsetattrat(int fd, char *path, int flags, struct vattr *vap)
1554 {
1555 vnode_t *startvp;
1556 vnode_t *vp;
1557 int error;
1558
1559 /*
1560 * Since we are never called to set the size of a file, we don't
1561 * need to check for non-blocking locks (via nbl_need_check(vp)).
1562 */
1563 ASSERT(!(vap->va_mask & AT_SIZE));
1564
1565 if ((error = fgetstartvp(fd, path, &startvp)) != 0)
1566 return (error);
1567 if (AU_AUDITING() && startvp != NULL)
1568 audit_setfsat_path(1);
1569
1570 /*
1571 * Do lookup for fchownat/fchmodat when path not NULL
1572 */
1573 if (path != NULL) {
1574 if (error = lookupnameat(path, UIO_USERSPACE,
1575 (flags == AT_SYMLINK_NOFOLLOW) ?
1576 NO_FOLLOW : FOLLOW,
1577 NULLVPP, &vp, startvp)) {
1578 if (startvp != NULL)
1579 VN_RELE(startvp);
1580 return (error);
1581 }
1582 } else {
1583 vp = startvp;
1584 ASSERT(vp);
1585 VN_HOLD(vp);
1586 }
1587
1588 if (vn_is_readonly(vp)) {
1589 error = EROFS;
1590 } else {
1591 error = VOP_SETATTR(vp, vap, 0, CRED(), NULL);
1592 }
1593
1594 if (startvp != NULL)
1595 VN_RELE(startvp);
1596 VN_RELE(vp);
1597
1598 return (error);
1599 }
1600
1601 /*
1602 * Return true if the given vnode is referenced by any
1603 * entry in the current process's file descriptor table.
1604 */
1605 int
1606 fisopen(vnode_t *vp)
1607 {
1608 int fd;
1609 file_t *fp;
1610 vnode_t *ovp;
1611 uf_info_t *fip = P_FINFO(curproc);
1612 uf_entry_t *ufp;
1613
1614 mutex_enter(&fip->fi_lock);
1615 for (fd = 0; fd < fip->fi_nfiles; fd++) {
1616 UF_ENTER(ufp, fip, fd);
1617 if ((fp = ufp->uf_file) != NULL &&
1618 (ovp = fp->f_vnode) != NULL && VN_CMP(vp, ovp)) {
1619 UF_EXIT(ufp);
1620 mutex_exit(&fip->fi_lock);
1621 return (1);
1622 }
1623 UF_EXIT(ufp);
1624 }
1625 mutex_exit(&fip->fi_lock);
1626 return (0);
1627 }
1628
1629 /*
1630 * Return zero if at least one file currently open (by curproc) shouldn't be
1631 * allowed to change zones.
1632 */
1633 int
1634 files_can_change_zones(void)
1635 {
1636 int fd;
1637 file_t *fp;
1638 uf_info_t *fip = P_FINFO(curproc);
1639 uf_entry_t *ufp;
1640
1641 mutex_enter(&fip->fi_lock);
1642 for (fd = 0; fd < fip->fi_nfiles; fd++) {
1643 UF_ENTER(ufp, fip, fd);
1644 if ((fp = ufp->uf_file) != NULL &&
1645 !vn_can_change_zones(fp->f_vnode)) {
1646 UF_EXIT(ufp);
1647 mutex_exit(&fip->fi_lock);
1648 return (0);
1649 }
1650 UF_EXIT(ufp);
1651 }
1652 mutex_exit(&fip->fi_lock);
1653 return (1);
1654 }
1655
1656 #ifdef DEBUG
1657
1658 /*
1659 * The following functions are only used in ASSERT()s elsewhere.
1660 * They do not modify the state of the system.
1661 */
1662
1663 /*
1664 * Return true (1) if the current thread is in the fpollinfo
1665 * list for this file descriptor, else false (0).
1666 */
1667 static int
1668 curthread_in_plist(uf_entry_t *ufp)
1669 {
1670 fpollinfo_t *fpip;
1671
1672 ASSERT(MUTEX_HELD(&ufp->uf_lock));
1673 for (fpip = ufp->uf_fpollinfo; fpip; fpip = fpip->fp_next)
1674 if (fpip->fp_thread == curthread)
1675 return (1);
1676 return (0);
1677 }
1678
1679 /*
1680 * Sanity check to make sure that after lwp_exit(),
1681 * curthread does not appear on any fd's fpollinfo list.
1682 */
1683 void
1684 checkfpollinfo(void)
1685 {
1686 int fd;
1687 uf_info_t *fip = P_FINFO(curproc);
1688 uf_entry_t *ufp;
1689
1690 mutex_enter(&fip->fi_lock);
1691 for (fd = 0; fd < fip->fi_nfiles; fd++) {
1692 UF_ENTER(ufp, fip, fd);
1693 ASSERT(!curthread_in_plist(ufp));
1694 UF_EXIT(ufp);
1695 }
1696 mutex_exit(&fip->fi_lock);
1697 }
1698
1699 /*
1700 * Return true (1) if the current thread is in the fpollinfo
1701 * list for this file descriptor, else false (0).
1702 * This is the same as curthread_in_plist(),
1703 * but is called w/o holding uf_lock.
1704 */
1705 int
1706 infpollinfo(int fd)
1707 {
1708 uf_info_t *fip = P_FINFO(curproc);
1709 uf_entry_t *ufp;
1710 int rc;
1711
1712 UF_ENTER(ufp, fip, fd);
1713 rc = curthread_in_plist(ufp);
1714 UF_EXIT(ufp);
1715 return (rc);
1716 }
1717
1718 #endif /* DEBUG */
1719
1720 /*
1721 * Add the curthread to fpollinfo list, meaning this fd is currently in the
1722 * thread's poll cache. Each lwp polling this file descriptor should call
1723 * this routine once.
1724 */
1725 void
1726 addfpollinfo(int fd)
1727 {
1728 struct uf_entry *ufp;
1729 fpollinfo_t *fpip;
1730 uf_info_t *fip = P_FINFO(curproc);
1731
1732 fpip = kmem_zalloc(sizeof (fpollinfo_t), KM_SLEEP);
1733 fpip->fp_thread = curthread;
1734 UF_ENTER(ufp, fip, fd);
1735 /*
1736 * Assert we are not already on the list, that is, that
1737 * this lwp did not call addfpollinfo twice for the same fd.
1738 */
1739 ASSERT(!curthread_in_plist(ufp));
1740 /*
1741 * addfpollinfo is always done inside the getf/releasef pair.
1742 */
1743 ASSERT(ufp->uf_refcnt >= 1);
1744 fpip->fp_next = ufp->uf_fpollinfo;
1745 ufp->uf_fpollinfo = fpip;
1746 UF_EXIT(ufp);
1747 }
1748
1749 /*
1750 * Delete curthread from fpollinfo list if it is there.
1751 */
1752 void
1753 delfpollinfo(int fd)
1754 {
1755 struct uf_entry *ufp;
1756 struct fpollinfo *fpip;
1757 struct fpollinfo **fpipp;
1758 uf_info_t *fip = P_FINFO(curproc);
1759
1760 UF_ENTER(ufp, fip, fd);
1761 for (fpipp = &ufp->uf_fpollinfo;
1762 (fpip = *fpipp) != NULL;
1763 fpipp = &fpip->fp_next) {
1764 if (fpip->fp_thread == curthread) {
1765 *fpipp = fpip->fp_next;
1766 kmem_free(fpip, sizeof (fpollinfo_t));
1767 break;
1768 }
1769 }
1770 /*
1771 * Assert that we are not still on the list, that is, that
1772 * this lwp did not call addfpollinfo twice for the same fd.
1773 */
1774 ASSERT(!curthread_in_plist(ufp));
1775 UF_EXIT(ufp);
1776 }
1777
1778 /*
1779 * fd is associated with a port. pfd is a pointer to the fd entry in the
1780 * cache of the port.
1781 */
1782
1783 void
1784 addfd_port(int fd, portfd_t *pfd)
1785 {
1786 struct uf_entry *ufp;
1787 uf_info_t *fip = P_FINFO(curproc);
1788
1789 UF_ENTER(ufp, fip, fd);
1790 /*
1791 * addfd_port is always done inside the getf/releasef pair.
1792 */
1793 ASSERT(ufp->uf_refcnt >= 1);
1794 if (ufp->uf_portfd == NULL) {
1795 /* first entry */
1796 ufp->uf_portfd = pfd;
1797 pfd->pfd_next = NULL;
1798 } else {
1799 pfd->pfd_next = ufp->uf_portfd;
1800 ufp->uf_portfd = pfd;
1801 pfd->pfd_next->pfd_prev = pfd;
1802 }
1803 UF_EXIT(ufp);
1804 }
1805
1806 void
1807 delfd_port(int fd, portfd_t *pfd)
1808 {
1809 struct uf_entry *ufp;
1810 uf_info_t *fip = P_FINFO(curproc);
1811
1812 UF_ENTER(ufp, fip, fd);
1813 /*
1814 * delfd_port is always done inside the getf/releasef pair.
1815 */
1816 ASSERT(ufp->uf_refcnt >= 1);
1817 if (ufp->uf_portfd == pfd) {
1818 /* remove first entry */
1819 ufp->uf_portfd = pfd->pfd_next;
1820 } else {
1821 pfd->pfd_prev->pfd_next = pfd->pfd_next;
1822 if (pfd->pfd_next != NULL)
1823 pfd->pfd_next->pfd_prev = pfd->pfd_prev;
1824 }
1825 UF_EXIT(ufp);
1826 }
1827
1828 static void
1829 port_close_fd(portfd_t *pfd)
1830 {
1831 portfd_t *pfdn;
1832
1833 /*
1834 * At this point, no other thread should access
1835 * the portfd_t list for this fd. The uf_file, uf_portfd
1836 * pointers in the uf_entry_t struct for this fd would
1837 * be set to NULL.
1838 */
1839 for (; pfd != NULL; pfd = pfdn) {
1840 pfdn = pfd->pfd_next;
1841 port_close_pfd(pfd);
1842 }
1843 }