2 * Copyright (c) 1998,1999 Adrian Sun (asun@zoology.washington.edu)
3 * All Rights Reserved. See COPYRIGHT for more information.
5 * Because fcntl locks are
6 * process-oriented, we need to keep around a list of file descriptors
7 * that refer to the same file.
9 * TODO: fix the race when reading/writing.
10 * keep a pool of both locks and reference counters around so that
11 * we can save on mallocs. we should also use a tree to keep things
17 #endif /* HAVE_CONFIG_H */
19 #include <atalk/adouble.h>
20 #include <atalk/logger.h>
21 #include <atalk/compat.h>
22 #include <atalk/errchk.h>
33 static const char *shmdstrfromoff(off_t off)
36 case AD_FILELOCK_OPEN_WR:
37 return "OPEN_WR_DATA";
38 case AD_FILELOCK_OPEN_RD:
39 return "OPEN_RD_DATA";
40 case AD_FILELOCK_RSRC_OPEN_WR:
41 return "OPEN_WR_RSRC";
42 case AD_FILELOCK_RSRC_OPEN_RD:
43 return "OPEN_RD_RSRC";
44 case AD_FILELOCK_DENY_WR:
45 return "DENY_WR_DATA";
46 case AD_FILELOCK_DENY_RD:
47 return "DENY_RD_DATA";
48 case AD_FILELOCK_RSRC_DENY_WR:
49 return "DENY_WR_RSRC";
50 case AD_FILELOCK_RSRC_DENY_RD:
51 return "DENY_RD_RSRC";
52 case AD_FILELOCK_OPEN_NONE:
53 return "OPEN_NONE_DATA";
54 case AD_FILELOCK_RSRC_OPEN_NONE:
55 return "OPEN_NONE_RSRC";
61 /* ----------------------- */
62 static int set_lock(int fd, int cmd, struct flock *lock)
66 LOG(log_debug, logtype_default, "set_lock(%s, %s, off: %jd (%s), len: %jd): BEGIN",
67 cmd == F_SETLK ? "F_SETLK" : "F_GETLK",
68 lock->l_type == F_RDLCK ? "F_RDLCK" : lock->l_type == F_WRLCK ? "F_WRLCK" : "F_UNLCK",
69 (intmax_t)lock->l_start,
70 shmdstrfromoff(lock->l_start),
71 (intmax_t)lock->l_len);
74 /* We assign fd = -2 for symlinks -> do nothing */
76 lock->l_type = F_UNLCK;
80 EC_NEG1_LOGSTR( fcntl(fd, cmd, lock),
81 "set_lock: %s", strerror(errno));
87 /* ----------------------- */
88 static int XLATE_FCNTL_LOCK(int type)
101 /* ----------------------- */
102 static int OVERLAP(off_t a, off_t alen, off_t b, off_t blen)
104 return (!alen && a <= b) ||
106 ( (a + alen > b) && (b + blen > a) );
109 /* allocation for lock regions. we allocate aggressively and shrink
110 * only in large chunks. */
111 #define ARRAY_BLOCK_SIZE 10
112 #define ARRAY_FREE_DELTA 100
114 /* remove a lock and compact space if necessary */
115 static void adf_freelock(struct ad_fd *ad, const int i)
117 adf_lock_t *lock = ad->adf_lock + i;
119 if (--(*lock->refcount) < 1) {
120 free(lock->refcount);
121 lock->lock.l_type = F_UNLCK;
122 set_lock(ad->adf_fd, F_SETLK, &lock->lock); /* unlock */
127 /* move another lock into the empty space */
128 if (i < ad->adf_lockcount) {
129 memcpy(lock, lock + ad->adf_lockcount - i, sizeof(adf_lock_t));
132 /* free extra cruft if we go past a boundary. we always want to
133 * keep at least some stuff around for allocations. this wastes
134 * a bit of space to save time on reallocations. */
135 if ((ad->adf_lockmax > ARRAY_FREE_DELTA) &&
136 (ad->adf_lockcount + ARRAY_FREE_DELTA < ad->adf_lockmax)) {
137 struct adf_lock_t *tmp;
139 tmp = (struct adf_lock_t *)
140 realloc(ad->adf_lock, sizeof(adf_lock_t)*
141 (ad->adf_lockcount + ARRAY_FREE_DELTA));
144 ad->adf_lockmax = ad->adf_lockcount + ARRAY_FREE_DELTA;
150 /* this needs to deal with the following cases:
151 * 1) free all UNIX byterange lock from any fork
152 * 2) free all locks of the requested fork
154 * i converted to using arrays of locks. everytime a lock
155 * gets removed, we shift all of the locks down.
157 static void adf_unlock(struct ad_fd *ad, const int fork)
159 adf_lock_t *lock = ad->adf_lock;
162 for (i = 0; i < ad->adf_lockcount; i++) {
163 if (lock[i].lock.l_start < AD_FILELOCK_BASE
164 || lock[i].user == fork) {
165 /* we're really going to delete this lock. note: read locks
166 are the only ones that allow refcounts > 1 */
168 /* we shifted things down, so we need to backtrack */
170 /* unlikely but realloc may have change adf_lock */
176 /* relock any byte lock that overlaps off/len. unlock everything
178 static void adf_relockrange(struct ad_fd *ad, int fd, off_t off, off_t len)
180 adf_lock_t *lock = ad->adf_lock;
183 for (i = 0; i < ad->adf_lockcount; i++) {
184 if (OVERLAP(off, len, lock[i].lock.l_start, lock[i].lock.l_len))
185 set_lock(fd, F_SETLK, &lock[i].lock);
190 /* find a byte lock that overlaps off/len for a particular open fork */
191 static int adf_findlock(struct ad_fd *ad,
192 const int fork, const int type,
196 adf_lock_t *lock = ad->adf_lock;
199 for (i = 0; i < ad->adf_lockcount; i++) {
200 if ((((type & ADLOCK_RD) && (lock[i].lock.l_type == F_RDLCK)) ||
201 ((type & ADLOCK_WR) && (lock[i].lock.l_type == F_WRLCK))) &&
202 (lock[i].user == fork) &&
203 OVERLAP(off, len, lock[i].lock.l_start, lock[i].lock.l_len)) {
211 /* search other fork lock lists */
212 static int adf_findxlock(struct ad_fd *ad,
213 const int fork, const int type,
217 adf_lock_t *lock = ad->adf_lock;
220 for (i = 0; i < ad->adf_lockcount; i++) {
221 if ((((type & ADLOCK_RD) && (lock[i].lock.l_type == F_RDLCK))
223 ((type & ADLOCK_WR) && (lock[i].lock.l_type == F_WRLCK)))
225 (lock[i].user != fork)
227 OVERLAP(off, len, lock[i].lock.l_start, lock[i].lock.l_len))
233 /* okay, this needs to do the following:
234 * 1) check current list of locks. error on conflict.
235 * 2) apply the lock. error on conflict with another process.
236 * 3) update the list of locks this file has.
238 * NOTE: this treats synchronization locks a little differently. we
239 * do the following things for those:
240 * 1) if the header file exists, all the locks go in the beginning
242 * 2) if the header file doesn't exist, we stick the locks
243 * in the locations specified by AD_FILELOCK_RD/WR.
245 #define LOCK_DATA_WR (0)
246 #define LOCK_DATA_RD (1)
247 #define LOCK_RSRC_WR (2)
248 #define LOCK_RSRC_RD (3)
250 #define LOCK_RSRC_DRD (4)
251 #define LOCK_RSRC_DWR (5)
252 #define LOCK_DATA_DRD (6)
253 #define LOCK_DATA_DWR (7)
255 #define LOCK_RSRC_NONE (8)
256 #define LOCK_DATA_NONE (9)
259 translate a data fork lock to an offset
262 static off_t df2off(off_t off)
265 if (off == AD_FILELOCK_OPEN_WR)
266 start = LOCK_DATA_WR;
267 else if (off == AD_FILELOCK_OPEN_RD)
268 start = LOCK_DATA_RD;
269 else if (off == AD_FILELOCK_DENY_RD)
270 start = LOCK_DATA_DRD;
271 else if (off == AD_FILELOCK_DENY_WR)
272 start = LOCK_DATA_DWR;
273 else if (off == AD_FILELOCK_OPEN_NONE)
274 start = LOCK_DATA_NONE;
279 translate a resource fork lock to an offset
282 static off_t hf2off(off_t off)
285 if (off == AD_FILELOCK_OPEN_WR)
286 start = LOCK_RSRC_WR;
287 else if (off == AD_FILELOCK_OPEN_RD)
288 start = LOCK_RSRC_RD;
289 else if (off == AD_FILELOCK_DENY_RD)
290 start = LOCK_RSRC_DRD;
291 else if (off == AD_FILELOCK_DENY_WR)
292 start = LOCK_RSRC_DWR;
293 else if (off == AD_FILELOCK_OPEN_NONE)
294 start = LOCK_RSRC_NONE;
299 translate a resource fork lock to an offset
301 static off_t rf2off(off_t off)
304 if (off == AD_FILELOCK_OPEN_WR)
305 start = AD_FILELOCK_RSRC_OPEN_WR;
306 else if (off == AD_FILELOCK_OPEN_RD)
307 start = AD_FILELOCK_RSRC_OPEN_RD;
308 else if (off == AD_FILELOCK_DENY_RD)
309 start = AD_FILELOCK_RSRC_DENY_RD;
310 else if (off == AD_FILELOCK_DENY_WR)
311 start = AD_FILELOCK_RSRC_DENY_WR;
312 else if (off == AD_FILELOCK_OPEN_NONE)
313 start = AD_FILELOCK_RSRC_OPEN_NONE;
320 * (1) Test against our own locks array
321 * (2) Test fcntl lock, locks from other processes
323 * @param adf (r) handle
324 * @param off (r) offset
325 * @param len (r) lenght
327 * @returns 1 if there's an existing lock, 0 if there's no lock,
328 * -1 in case any error occured
330 static int testlock(const struct ad_fd *adf, off_t off, off_t len)
338 plock = adf->adf_lock;
339 lock.l_whence = SEEK_SET;
342 /* (1) Do we have a lock ? */
343 for (i = 0; i < adf->adf_lockcount; i++) {
344 if (OVERLAP(lock.l_start, 1, plock[i].lock.l_start, plock[i].lock.l_len))
348 /* (2) Does another process have a lock? */
349 lock.l_type = (adf->adf_flags & O_RDWR) ? F_WRLCK : F_RDLCK;
351 if (set_lock(adf->adf_fd, F_GETLK, &lock) < 0) {
352 /* is that kind of error possible ?*/
353 return (errno == EACCES || errno == EAGAIN) ? 1 : -1;
356 if (lock.l_type == F_UNLCK) {
362 static uint16_t ad_openforks_v2(struct adouble *ad, uint16_t attrbits)
368 if (!(attrbits & (ATTRBIT_DOPEN | ATTRBIT_ROPEN))) {
370 /* XXX know the locks layout:
371 AD_FILELOCK_OPEN_WR is first
372 and use it for merging requests
374 if (ad_meta_fileno(ad) != -1) {
375 /* there's a resource fork test the four bytes for
376 * data RW/RD and fork RW/RD locks in one request
383 /* no resource fork, only data RD/RW may exist */
384 adf = &ad->ad_data_fork;
385 off = AD_FILELOCK_OPEN_WR;
388 if (!testlock(adf, off, len))
391 /* either there's a lock or we already know one
394 if (!(attrbits & ATTRBIT_DOPEN)) {
395 if (ad_meta_fileno(ad) != -1) {
400 adf = &ad->ad_data_fork;
401 off = AD_FILELOCK_OPEN_WR;
403 ret = testlock(adf, off, 2) > 0? ATTRBIT_DOPEN : 0;
406 if (!(attrbits & ATTRBIT_ROPEN)) {
407 if (ad_meta_fileno(ad) != -1) {
410 ret |= testlock(adf, off, 2) > 0? ATTRBIT_ROPEN : 0;
417 /* test for sharemode locks, adouble:ea stores them on the datafork */
418 static uint16_t ad_openforks_ea(struct adouble *ad, uint16_t attrbits)
425 if (ad_data_fileno(ad) == -1)
428 if (!(attrbits & (ATTRBIT_DOPEN | ATTRBIT_ROPEN))) {
429 /* Test all 4 locks at once */
430 off = AD_FILELOCK_OPEN_WR;
432 if (testlock(&ad->ad_data_fork, off, len) == 0)
436 /* either there's a lock or we already know one fork is open */
438 if (!(attrbits & ATTRBIT_DOPEN)) {
439 off = AD_FILELOCK_OPEN_WR;
440 ret = testlock(&ad->ad_data_fork, off, 2) > 0 ? ATTRBIT_DOPEN : 0;
443 if (!(attrbits & ATTRBIT_ROPEN)) {
444 off = AD_FILELOCK_RSRC_OPEN_WR;
445 ret |= testlock(&ad->ad_data_fork, off, 2) > 0? ATTRBIT_ROPEN : 0;
451 static int ad_testlock_v2(struct adouble *ad, int eid, const off_t off)
457 if (eid == ADEID_DFORK) {
458 adf = &ad->ad_data_fork;
459 if (ad_meta_fileno(ad) != -1) {
461 lock_offset = df2off(off);
464 if (ad_meta_fileno(ad) == -1) {
465 /* there's no resource fork. return no lock */
469 lock_offset = hf2off(off);
471 return testlock(adf, lock_offset, 1);
474 static int ad_testlock_ea(struct adouble *ad, int eid, const off_t off)
478 if (eid == ADEID_DFORK) {
481 lock_offset = rf2off(off);
483 return testlock(&ad->ad_data_fork, lock_offset, 1);
486 #define LTYPE2STRBUFSIZ 128
487 static const char *locktypetostr(int type)
490 static char buf[LTYPE2STRBUFSIZ];
495 strlcat(buf, "CLR", LTYPE2STRBUFSIZ);
499 if (type & ADLOCK_RD) {
501 strlcat(buf, "|", LTYPE2STRBUFSIZ);
502 strlcat(buf, "RD", LTYPE2STRBUFSIZ);
505 if (type & ADLOCK_WR) {
507 strlcat(buf, "|", LTYPE2STRBUFSIZ);
508 strlcat(buf, "WR", LTYPE2STRBUFSIZ);
511 if (type & ADLOCK_UPGRADE) {
513 strlcat(buf, "|", LTYPE2STRBUFSIZ);
514 strlcat(buf, "UPG", LTYPE2STRBUFSIZ);
517 if (type & ADLOCK_FILELOCK) {
519 strlcat(buf, "|", LTYPE2STRBUFSIZ);
520 strlcat(buf, "FILELOCK", LTYPE2STRBUFSIZ);
527 /******************************************************************************
529 ******************************************************************************/
531 int ad_lock(struct adouble *ad, uint32_t eid, int locktype, off_t off, off_t len, int fork)
539 int ret = 0, fcntl_lock_err = 0;
541 LOG(log_debug, logtype_default, "ad_lock(\"%s\", %s, %s, off: %jd (%s), len: %jd): BEGIN",
542 ad->ad_m_name ? ad->ad_m_name : "???",
543 eid == ADEID_DFORK ? "data" : "reso",
544 locktypetostr(locktype),
549 if ((locktype & ADLOCK_FILELOCK) && (len != 1)) {
558 if (eid == ADEID_DFORK) {
559 adf = &ad->ad_data_fork;
560 if ((ad->ad_vers == AD_VERSION2) && (type & ADLOCK_FILELOCK)) {
561 if (ad_meta_fileno(ad) != -1) { /* META */
563 lock.l_start = df2off(off);
567 switch (ad->ad_vers) {
569 if (ad_meta_fileno(ad) == -1 || ad_reso_fileno(ad) == -1) {
570 /* there's no meta data. return a lock error
571 * otherwise if a second process is able to create it
572 * locks are a mess. */
577 if (type & ADLOCK_FILELOCK) {
578 adf = ad->ad_mdp; /* either resource or meta data (set in ad_open) */
579 lock.l_start = hf2off(off);
581 /* we really want the resource fork it's a byte lock */
582 adf = &ad->ad_resource_fork;
583 lock.l_start += ad_getentryoff(ad, eid);
588 if (type & ADLOCK_FILELOCK) {
589 adf = &ad->ad_data_fork;
590 lock.l_start = rf2off(off);
596 lock.l_start= ADEDOFF_RFORK_OSX + off;
607 /* NOTE: we can't write lock a read-only file. on those, we just
608 * make sure that we have a read lock set. that way, we at least prevent
609 * someone else from really setting a deny read/write on the file.
611 if (!(adf->adf_flags & O_RDWR) && (type & ADLOCK_WR)) {
612 type = (type & ~ADLOCK_WR) | ADLOCK_RD;
615 lock.l_type = XLATE_FCNTL_LOCK(type & ADLOCK_MASK);
616 lock.l_whence = SEEK_SET;
619 /* byte_lock(len=-1) lock whole file */
620 if (len == BYTELOCK_MAX) {
621 lock.l_len -= lock.l_start; /* otherwise EOVERFLOW error */
624 /* see if it's locked by another fork.
625 * NOTE: this guarantees that any existing locks must be at most
626 * read locks. we use ADLOCK_WR/RD because F_RD/WRLCK aren't
627 * guaranteed to be ORable. */
628 if (adf_findxlock(adf, fork, ADLOCK_WR |
629 ((type & ADLOCK_WR) ? ADLOCK_RD : 0),
630 lock.l_start, lock.l_len) > -1) {
636 /* look for any existing lock that we may have */
637 i = adf_findlock(adf, fork, ADLOCK_RD | ADLOCK_WR, lock.l_start, lock.l_len);
638 adflock = (i < 0) ? NULL : adf->adf_lock + i;
640 /* here's what we check for:
641 1) we're trying to re-lock a lock, but we didn't specify an update.
642 2) we're trying to free only part of a lock.
643 3) we're trying to free a non-existent lock. */
644 if ( (!adflock && (lock.l_type == F_UNLCK))
647 && !(type & ADLOCK_UPGRADE)
648 && ((lock.l_type != F_UNLCK)
649 || (adflock->lock.l_start != lock.l_start)
650 || (adflock->lock.l_len != lock.l_len) ))
658 /* now, update our list of locks */
660 if (lock.l_type == F_UNLCK) {
661 adf_freelock(adf, i);
665 /* attempt to lock the file. */
666 if (set_lock(adf->adf_fd, F_SETLK, &lock) < 0) {
671 /* we upgraded this lock. */
672 if (adflock && (type & ADLOCK_UPGRADE)) {
673 memcpy(&adflock->lock, &lock, sizeof(lock));
677 /* it wasn't an upgrade */
679 if (lock.l_type == F_RDLCK) {
680 oldlock = adf_findxlock(adf, fork, ADLOCK_RD, lock.l_start, lock.l_len);
683 /* no more space. this will also happen if lockmax == lockcount == 0 */
684 if (adf->adf_lockmax == adf->adf_lockcount) {
685 adf_lock_t *tmp = (adf_lock_t *)
686 realloc(adf->adf_lock, sizeof(adf_lock_t)*
687 (adf->adf_lockmax + ARRAY_BLOCK_SIZE));
689 ret = fcntl_lock_err = -1;
693 adf->adf_lockmax += ARRAY_BLOCK_SIZE;
695 adflock = adf->adf_lock + adf->adf_lockcount;
698 memcpy(&adflock->lock, &lock, sizeof(lock));
699 adflock->user = fork;
701 adflock->refcount = (adf->adf_lock + oldlock)->refcount;
702 } else if ((adflock->refcount = calloc(1, sizeof(int))) == NULL) {
703 ret = fcntl_lock_err = 1;
707 (*adflock->refcount)++;
708 adf->adf_lockcount++;
712 if (fcntl_lock_err != 0) {
713 lock.l_type = F_UNLCK;
714 set_lock(adf->adf_fd, F_SETLK, &lock);
717 LOG(log_debug, logtype_default, "ad_lock: END: %d", ret);
721 int ad_tmplock(struct adouble *ad, uint32_t eid, int locktype, off_t off, off_t len, int fork)
728 LOG(log_debug, logtype_default, "ad_tmplock(\"%s\", %s, %s, off: %jd (%s), len: %jd): BEGIN",
729 ad->ad_m_name ? ad->ad_m_name : "???",
730 eid == ADEID_DFORK ? "data" : "reso",
731 locktypetostr(locktype),
738 if (eid == ADEID_DFORK) {
739 adf = &ad->ad_data_fork;
742 adf = &ad->ad_resource_fork;
743 if (adf->adf_fd == -1) {
744 /* there's no resource fork. return success */
748 /* if ADLOCK_FILELOCK we want a lock from offset 0
749 * it's used when deleting a file:
750 * in open we put read locks on meta datas
751 * in delete a write locks on the whole file
752 * so if the file is open by somebody else it fails
754 if (!(type & ADLOCK_FILELOCK))
755 lock.l_start += ad_getentryoff(ad, eid);
758 if (!(adf->adf_flags & O_RDWR) && (type & ADLOCK_WR)) {
759 type = (type & ~ADLOCK_WR) | ADLOCK_RD;
762 lock.l_type = XLATE_FCNTL_LOCK(type & ADLOCK_MASK);
763 lock.l_whence = SEEK_SET;
766 /* see if it's locked by another fork. */
767 if (fork && adf_findxlock(adf, fork,
768 ADLOCK_WR | ((type & ADLOCK_WR) ? ADLOCK_RD : 0),
769 lock.l_start, lock.l_len) > -1) {
775 /* okay, we might have ranges byte-locked. we need to make sure that
776 * we restore the appropriate ranges once we're done. so, we check
777 * for overlap on an unlock and relock.
778 * XXX: in the future, all the byte locks will be sorted and contiguous.
779 * we just want to upgrade all the locks and then downgrade them
781 err = set_lock(adf->adf_fd, F_SETLK, &lock);
782 if (!err && (lock.l_type == F_UNLCK))
783 adf_relockrange(adf, adf->adf_fd, lock.l_start, len);
786 LOG(log_debug, logtype_default, "ad_tmplock: END: %d", err);
790 /* --------------------- */
791 void ad_unlock(struct adouble *ad, const int fork)
793 LOG(log_debug, logtype_default, "ad_unlock(\"%s\"): BEGIN", ad->ad_m_name ? ad->ad_m_name : "???");
795 if (ad_data_fileno(ad) != -1) {
796 adf_unlock(&ad->ad_data_fork, fork);
798 if (ad_reso_fileno(ad) != -1) {
799 adf_unlock(&ad->ad_resource_fork, fork);
802 LOG(log_debug, logtype_default, "ad_unlock(\"%s\"): END", ad->ad_m_name ? ad->ad_m_name : "???");
806 * Test for a share mode lock
808 * @param ad (rw) handle
809 * @param eid (r) datafork or ressource fork
810 * @param off (r) sharemode lock to test
812 * @returns 1 if there's an existing lock, 0 if there's no lock,
813 * -1 in case any error occured
815 int ad_testlock(struct adouble *ad, int eid, const off_t off)
819 LOG(log_debug, logtype_default, "ad_testlock(\"%s\", %s, off: %jd (%s): BEGIN",
820 ad->ad_m_name ? ad->ad_m_name : "???",
821 eid == ADEID_DFORK ? "data" : "reso",
823 shmdstrfromoff(off));
825 switch (ad->ad_vers) {
827 ret = ad_testlock_v2(ad, eid, off);
830 ret = ad_testlock_ea(ad, eid, off);
837 LOG(log_debug, logtype_default, "ad_testlock: END: %d", ret);
842 * Return if a file is open by another process.
844 * Optimized for the common case:
845 * - there's no locks held by another process (clients)
846 * - or we already know the answer and don't need to test (attrbits)
848 * @param ad (rw) handle
849 * @param attrbits (r) forks opened by us
850 * @returns bitflags ATTRBIT_DOPEN | ATTRBIT_ROPEN if
851 * other process has fork of file opened
853 uint16_t ad_openforks(struct adouble *ad, uint16_t attrbits)
855 switch (ad->ad_vers) {
857 return ad_openforks_v2(ad, attrbits);
859 return ad_openforks_ea(ad, attrbits);