/*
- * $Id: ad_lock.c,v 1.3 2001-06-29 14:14:46 rufustfirefly Exp $
- *
* Copyright (c) 1998,1999 Adrian Sun (asun@zoology.washington.edu)
* All Rights Reserved. See COPYRIGHT for more information.
*
- * Byte-range locks. This uses either whole-file flocks to fake byte
- * locks or fcntl-based actual byte locks. Because fcntl locks are
+ * Because fcntl locks are
* process-oriented, we need to keep around a list of file descriptors
- * that refer to the same file. Currently, this doesn't serialize access
- * to the locks. as a result, there's the potential for race conditions.
+ * that refer to the same file.
*
* TODO: fix the race when reading/writing.
* keep a pool of both locks and reference counters around so that
#include "config.h"
#endif /* HAVE_CONFIG_H */
+#include <atalk/adouble.h>
+#include <atalk/logger.h>
+#include <atalk/compat.h>
+#include <atalk/errchk.h>
+#include <atalk/util.h>
+
#include <stdio.h>
#include <stdlib.h>
-#include <string.h>
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#endif /* HAVE_UNISTD_H */
-#ifdef HAVE_FCNTL_H
-#include <fcntl.h>
-#endif /* HAVE_FCNTL_H */
#include <errno.h>
+#include <inttypes.h>
-#include <atalk/adouble.h>
+#include <string.h>
-#include "ad_private.h"
+#include "ad_lock.h"
+
+static const char *shmdstrfromoff(off_t off)
+{
+ switch (off) {
+ case AD_FILELOCK_OPEN_WR:
+ return "OPEN_WR_DATA";
+ case AD_FILELOCK_OPEN_RD:
+ return "OPEN_RD_DATA";
+ case AD_FILELOCK_RSRC_OPEN_WR:
+ return "OPEN_WR_RSRC";
+ case AD_FILELOCK_RSRC_OPEN_RD:
+ return "OPEN_RD_RSRC";
+ case AD_FILELOCK_DENY_WR:
+ return "DENY_WR_DATA";
+ case AD_FILELOCK_DENY_RD:
+ return "DENY_RD_DATA";
+ case AD_FILELOCK_RSRC_DENY_WR:
+ return "DENY_WR_RSRC";
+ case AD_FILELOCK_RSRC_DENY_RD:
+ return "DENY_RD_RSRC";
+ case AD_FILELOCK_OPEN_NONE:
+ return "OPEN_NONE_DATA";
+ case AD_FILELOCK_RSRC_OPEN_NONE:
+ return "OPEN_NONE_RSRC";
+ default:
+ return "-";
+ }
+}
-/* translate between ADLOCK styles and specific locking mechanisms */
-#define XLATE_FLOCK(type) ((type) == ADLOCK_RD ? LOCK_SH : \
-((type) == ADLOCK_WR ? LOCK_EX : \
- ((type) == ADLOCK_CLR ? LOCK_UN : -1)))
+/* ----------------------- */
+static int set_lock(int fd, int cmd, struct flock *lock)
+{
+ EC_INIT;
+
+ LOG(log_debug, logtype_default, "set_lock(fd: %d, %s, %s, off: %jd (%s), len: %jd): BEGIN",
+ fd, cmd == F_SETLK ? "F_SETLK" : "F_GETLK",
+ lock->l_type == F_RDLCK ? "F_RDLCK" : lock->l_type == F_WRLCK ? "F_WRLCK" : "F_UNLCK",
+ (intmax_t)lock->l_start,
+ shmdstrfromoff(lock->l_start),
+ (intmax_t)lock->l_len);
+
+ if (fd == -2) {
+ /* We assign fd = -2 for symlinks -> do nothing */
+ if (cmd == F_GETLK)
+ lock->l_type = F_UNLCK;
+ return 0;
+ }
-#define XLATE_FCNTL_LOCK(type) ((type) == ADLOCK_RD ? F_RDLCK : \
-((type) == ADLOCK_WR ? F_WRLCK : \
- ((type) == ADLOCK_CLR ? F_UNLCK : -1)))
-
-#define OVERLAP(a,alen,b,blen) ((!(alen) && (a) <= (b)) || \
- (!(blen) && (b) <= (a)) || \
- ((((a) + (alen)) > (b)) && \
- (((b) + (blen)) > (a))))
+ EC_NEG1( fcntl(fd, cmd, lock) );
+EC_CLEANUP:
+ EC_EXIT;
+}
+
+/* ----------------------- */
+static int XLATE_FCNTL_LOCK(int type)
+{
+ switch(type) {
+ case ADLOCK_RD:
+ return F_RDLCK;
+ case ADLOCK_WR:
+ return F_WRLCK;
+ case ADLOCK_CLR:
+ return F_UNLCK;
+ }
+ return -1;
+}
+
+/* ----------------------- */
+static int OVERLAP(off_t a, off_t alen, off_t b, off_t blen)
+{
+ return (!alen && a <= b) ||
+ (!blen && b <= a) ||
+ ( (a + alen > b) && (b + blen > a) );
+}
/* allocation for lock regions. we allocate aggressively and shrink
* only in large chunks. */
#define ARRAY_FREE_DELTA 100
/* remove a lock and compact space if necessary */
-static __inline__ void adf_freelock(struct ad_fd *ad, const int i)
+static void adf_freelock(struct ad_fd *ad, const int i)
{
adf_lock_t *lock = ad->adf_lock + i;
if (--(*lock->refcount) < 1) {
free(lock->refcount);
- lock->lock.l_type = F_UNLCK;
- fcntl(ad->adf_fd, F_SETLK, &lock->lock); /* unlock */
+ lock->lock.l_type = F_UNLCK;
+ set_lock(ad->adf_fd, F_SETLK, &lock->lock); /* unlock */
}
ad->adf_lockcount--;
/* this needs to deal with the following cases:
- * 1) user is the only user of the lock
- * 2) user shares a read lock with another user
+ * 1) free all UNIX byterange lock from any fork
+ * 2) free all locks of the requested fork
*
* i converted to using arrays of locks. everytime a lock
* gets removed, we shift all of the locks down.
*/
-static __inline__ void adf_unlock(struct ad_fd *ad, int fd, const int user)
+static void adf_unlock(struct adouble *ad, struct ad_fd *adf, const int fork, int unlckbrl)
{
- adf_lock_t *lock = ad->adf_lock;
+ adf_lock_t *lock = adf->adf_lock;
int i;
- for (i = 0; i < ad->adf_lockcount; i++) {
- if (lock[i].user == user) {
- /* we're really going to delete this lock. note: read locks
- are the only ones that allow refcounts > 1 */
- adf_freelock(ad, i);
- i--; /* we shifted things down, so we need to backtrack */
- }
+ for (i = 0; i < adf->adf_lockcount; i++) {
+ if ((unlckbrl && lock[i].lock.l_start < AD_FILELOCK_BASE)
+ || lock[i].user == fork) {
+ /* we're really going to delete this lock. note: read locks
+ are the only ones that allow refcounts > 1 */
+ adf_freelock(adf, i);
+ /* we shifted things down, so we need to backtrack */
+ i--;
+ /* unlikely but realloc may have change adf_lock */
+ lock = adf->adf_lock;
+ }
}
}
/* relock any byte lock that overlaps off/len. unlock everything
* else. */
-static __inline__ void adf_relockrange(struct ad_fd *ad, int fd,
- const off_t off, const size_t len)
+static void adf_relockrange(struct ad_fd *ad, int fd, off_t off, off_t len)
{
adf_lock_t *lock = ad->adf_lock;
int i;
for (i = 0; i < ad->adf_lockcount; i++) {
- if (OVERLAP(off, len, lock[i].lock.l_start, lock[i].lock.l_len))
- fcntl(fd, F_SETLK, &lock[i].lock);
+ if (OVERLAP(off, len, lock[i].lock.l_start, lock[i].lock.l_len))
+ set_lock(fd, F_SETLK, &lock[i].lock);
}
}
-/* find a byte lock that overlaps off/len for a particular user */
-static __inline__ int adf_findlock(struct ad_fd *ad,
- const int user, const int type,
- const off_t off,
- const size_t len)
+/* find a byte lock that overlaps off/len for a particular open fork */
+static int adf_findlock(struct ad_fd *ad,
+ const int fork, const int type,
+ const off_t off,
+ const off_t len)
{
adf_lock_t *lock = ad->adf_lock;
int i;
for (i = 0; i < ad->adf_lockcount; i++) {
if ((((type & ADLOCK_RD) && (lock[i].lock.l_type == F_RDLCK)) ||
((type & ADLOCK_WR) && (lock[i].lock.l_type == F_WRLCK))) &&
- (lock[i].user == user) &&
+ (lock[i].user == fork) &&
OVERLAP(off, len, lock[i].lock.l_start, lock[i].lock.l_len)) {
return i;
}
}
-
return -1;
}
-/* search other user lock lists */
-static __inline__ int adf_findxlock(struct ad_fd *ad,
- const int user, const int type,
- const off_t off,
- const size_t len)
+/* search other fork lock lists */
+static int adf_findxlock(struct ad_fd *ad,
+ const int fork, const int type,
+ const off_t off,
+ const off_t len)
{
- adf_lock_t *lock = ad->adf_lock;
- int i;
+ adf_lock_t *lock = ad->adf_lock;
+ int i;
- for (i = 0; i < ad->adf_lockcount; i++) {
- if ((((type & ADLOCK_RD) && (lock[i].lock.l_type == F_RDLCK)) ||
- ((type & ADLOCK_WR) && (lock[i].lock.l_type == F_WRLCK))) &&
- (lock[i].user != user) &&
- OVERLAP(off, len, lock[i].lock.l_start, lock[i].lock.l_len))
- return i;
- }
- return -1;
+ for (i = 0; i < ad->adf_lockcount; i++) {
+ if ((((type & ADLOCK_RD) && (lock[i].lock.l_type == F_RDLCK))
+ ||
+ ((type & ADLOCK_WR) && (lock[i].lock.l_type == F_WRLCK)))
+ &&
+ (lock[i].user != fork)
+ &&
+ OVERLAP(off, len, lock[i].lock.l_start, lock[i].lock.l_len))
+ return i;
+ }
+ return -1;
}
/* okay, this needs to do the following:
* 2) if the header file doesn't exist, we stick the locks
* in the locations specified by AD_FILELOCK_RD/WR.
*/
-#define LOCK_RSRC_RD (0)
-#define LOCK_RSRC_WR (1)
-#define LOCK_DATA_RD (2)
-#define LOCK_DATA_WR (3)
-int ad_fcntl_lock(struct adouble *ad, const u_int32_t eid, const int type,
- const off_t off, const size_t len, const int user)
+
+/* --------------
+ translate a resource fork lock to an offset
+*/
+static off_t rf2off(off_t off)
{
- struct flock lock;
- struct ad_fd *adf;
- adf_lock_t *adflock, *oldlock;
- int i;
+ off_t start = off;
+ if (off == AD_FILELOCK_OPEN_WR)
+ start = AD_FILELOCK_RSRC_OPEN_WR;
+ else if (off == AD_FILELOCK_OPEN_RD)
+ start = AD_FILELOCK_RSRC_OPEN_RD;
+ else if (off == AD_FILELOCK_DENY_RD)
+ start = AD_FILELOCK_RSRC_DENY_RD;
+ else if (off == AD_FILELOCK_DENY_WR)
+ start = AD_FILELOCK_RSRC_DENY_WR;
+ else if (off == AD_FILELOCK_OPEN_NONE)
+ start = AD_FILELOCK_RSRC_OPEN_NONE;
+ return start;
+}
+
+/*!
+ * Test a lock
+ *
+ * (1) Test against our own locks array
+ * (2) Test fcntl lock, locks from other processes
+ *
+ * @param adf (r) handle
+ * @param off (r) offset
+ * @param len (r) lenght
+ *
+ * @returns 1 if there's an existing lock, 0 if there's no lock,
+ * -1 in case any error occured
+ */
+static int testlock(const struct ad_fd *adf, off_t off, off_t len)
+{
+ struct flock lock;
+ adf_lock_t *plock;
+ int i;
+
+ lock.l_start = off;
+
+ plock = adf->adf_lock;
+ lock.l_whence = SEEK_SET;
+ lock.l_len = len;
+
+ /* (1) Do we have a lock ? */
+ for (i = 0; i < adf->adf_lockcount; i++) {
+ if (OVERLAP(lock.l_start, 1, plock[i].lock.l_start, plock[i].lock.l_len))
+ return 1;
+ }
+
+ /* (2) Does another process have a lock? */
+ lock.l_type = (adf->adf_flags & O_RDWR) ? F_WRLCK : F_RDLCK;
+
+ if (set_lock(adf->adf_fd, F_GETLK, &lock) < 0) {
+ /* is that kind of error possible ?*/
+ return (errno == EACCES || errno == EAGAIN) ? 1 : -1;
+ }
- lock.l_start = off;
- if (eid == ADEID_DFORK) {
- if ((type & ADLOCK_FILELOCK) && (ad_hfileno(ad) != -1)) {
- adf = &ad->ad_hf;
- if (off == AD_FILELOCK_WR)
- lock.l_start = LOCK_DATA_WR;
- else if (off == AD_FILELOCK_RD)
- lock.l_start = LOCK_DATA_RD;
- } else
- adf = &ad->ad_df;
-
- } else { /* rfork */
- adf = &ad->ad_hf;
+ if (lock.l_type == F_UNLCK) {
+ return 0;
+ }
+ return 1;
+}
+
+#define LTYPE2STRBUFSIZ 128
+static const char *locktypetostr(int type)
+{
+ int first = 1;
+ static char buf[LTYPE2STRBUFSIZ];
+
+ buf[0] = 0;
+
+ if (type == 0) {
+ strlcat(buf, "CLR", LTYPE2STRBUFSIZ);
+ first = 0;
+ return buf;
+ }
+ if (type & ADLOCK_RD) {
+ if (!first)
+ strlcat(buf, "|", LTYPE2STRBUFSIZ);
+ strlcat(buf, "RD", LTYPE2STRBUFSIZ);
+ first = 0;
+ }
+ if (type & ADLOCK_WR) {
+ if (!first)
+ strlcat(buf, "|", LTYPE2STRBUFSIZ);
+ strlcat(buf, "WR", LTYPE2STRBUFSIZ);
+ first = 0;
+ }
+ if (type & ADLOCK_UPGRADE) {
+ if (!first)
+ strlcat(buf, "|", LTYPE2STRBUFSIZ);
+ strlcat(buf, "UPG", LTYPE2STRBUFSIZ);
+ first = 0;
+ }
if (type & ADLOCK_FILELOCK) {
- if (off == AD_FILELOCK_WR)
- lock.l_start = LOCK_RSRC_WR;
- else if (off == AD_FILELOCK_RD)
- lock.l_start = LOCK_RSRC_RD;
- } else
- lock.l_start += ad_getentryoff(ad, eid);
- }
+ if (!first)
+ strlcat(buf, "|", LTYPE2STRBUFSIZ);
+ strlcat(buf, "FILELOCK", LTYPE2STRBUFSIZ);
+ first = 0;
+ }
- lock.l_type = XLATE_FCNTL_LOCK(type & ADLOCK_MASK);
+ return buf;
+}
- /* see if it's locked by another user.
- * NOTE: this guarantees that any existing locks must be at most
- * read locks. we use ADLOCK_WR/RD because F_RD/WRLCK aren't
- * guaranteed to be ORable. */
- if (adf_findxlock(adf, user, ADLOCK_WR |
- ((type & ADLOCK_WR) ? ADLOCK_RD : 0),
- lock.l_start, len) > -1) {
- errno = EACCES;
- return -1;
- }
+/******************************************************************************
+ * Public functions
+ ******************************************************************************/
+
+int ad_lock(struct adouble *ad, uint32_t eid, int locktype, off_t off, off_t len, int fork)
+{
+ struct flock lock;
+ struct ad_fd *adf;
+ adf_lock_t *adflock;
+ int oldlock;
+ int i;
+ int type;
+ int ret = 0, fcntl_lock_err = 0;
+
+ LOG(log_debug, logtype_default, "ad_lock(%s, %s, off: %jd (%s), len: %jd): BEGIN",
+ eid == ADEID_DFORK ? "data" : "reso",
+ locktypetostr(locktype),
+ (intmax_t)off,
+ shmdstrfromoff(off),
+ (intmax_t)len);
+
+ if ((locktype & ADLOCK_FILELOCK) && (len != 1))
+ AFP_PANIC("lock API error");
+
+ type = locktype;
+
+ if (eid == ADEID_DFORK) {
+ adf = &ad->ad_data_fork;
+ lock.l_start = off;
+ } else { /* rfork */
+ if (type & ADLOCK_FILELOCK) {
+ adf = &ad->ad_data_fork;
+ lock.l_start = rf2off(off);
+ } else {
+ adf = ad->ad_rfp;
+ lock.l_start = off + ad_getentryoff(ad, ADEID_RFORK);
+ }
+ }
+
+ /* NOTE: we can't write lock a read-only file. on those, we just
+ * make sure that we have a read lock set. that way, we at least prevent
+ * someone else from really setting a deny read/write on the file.
+ */
+ if (!(adf->adf_flags & O_RDWR) && (type & ADLOCK_WR)) {
+ type = (type & ~ADLOCK_WR) | ADLOCK_RD;
+ }
- /* look for any existing lock that we may have */
- i = adf_findlock(adf, user, ADLOCK_RD | ADLOCK_WR, lock.l_start, len);
- adflock = (i < 0) ? NULL : adf->adf_lock + i;
-
- /* here's what we check for:
- 1) we're trying to re-lock a lock, but we didn't specify an update.
- 2) we're trying to free only part of a lock.
- 3) we're trying to free a non-existent lock. */
- if ((!adflock && (lock.l_type == F_UNLCK)) ||
- (adflock && !(type & ADLOCK_UPGRADE) &&
- ((lock.l_type != F_UNLCK) || (adflock->lock.l_start != lock.l_start) ||
- (adflock->lock.l_len != len)))) {
- errno = EINVAL;
- return -1;
- }
+ lock.l_type = XLATE_FCNTL_LOCK(type & ADLOCK_MASK);
+ lock.l_whence = SEEK_SET;
+ lock.l_len = len;
- lock.l_whence = SEEK_SET;
- lock.l_len = len;
+ /* byte_lock(len=-1) lock whole file */
+ if (len == BYTELOCK_MAX) {
+ lock.l_len -= lock.l_start; /* otherwise EOVERFLOW error */
+ }
- /* now, update our list of locks */
- /* clear the lock */
- if (lock.l_type == F_UNLCK) {
- adf_freelock(adf, i);
- return 0;
- }
+ /* see if it's locked by another fork.
+ * NOTE: this guarantees that any existing locks must be at most
+ * read locks. we use ADLOCK_WR/RD because F_RD/WRLCK aren't
+ * guaranteed to be ORable. */
+ if (adf_findxlock(adf, fork, ADLOCK_WR |
+ ((type & ADLOCK_WR) ? ADLOCK_RD : 0),
+ lock.l_start, lock.l_len) > -1) {
+ errno = EACCES;
+ ret = -1;
+ goto exit;
+ }
+
+ /* look for any existing lock that we may have */
+ i = adf_findlock(adf, fork, ADLOCK_RD | ADLOCK_WR, lock.l_start, lock.l_len);
+ adflock = (i < 0) ? NULL : adf->adf_lock + i;
+
+ /* here's what we check for:
+ 1) we're trying to re-lock a lock, but we didn't specify an update.
+ 2) we're trying to free only part of a lock.
+ 3) we're trying to free a non-existent lock. */
+ if ( (!adflock && (lock.l_type == F_UNLCK))
+ ||
+ (adflock
+ && !(type & ADLOCK_UPGRADE)
+ && ((lock.l_type != F_UNLCK)
+ || (adflock->lock.l_start != lock.l_start)
+ || (adflock->lock.l_len != lock.l_len) ))
+ ) {
+ errno = EINVAL;
+ ret = -1;
+ goto exit;
+ }
- /* attempt to lock the file. */
- if (fcntl(adf->adf_fd, F_SETLK, &lock) < 0)
- return -1;
- /* we upgraded this lock. */
- if (adflock && (type & ADLOCK_UPGRADE)) {
- memcpy(&adflock->lock, &lock, sizeof(lock));
- return 0;
- }
-
- /* it wasn't an upgrade */
- oldlock = NULL;
- if ((lock.l_type = F_RDLCK) &&
- ((i = adf_findxlock(adf, user, ADLOCK_RD, lock.l_start, len)) > -1)) {
- oldlock = adf->adf_lock + i;
- }
+ /* now, update our list of locks */
+ /* clear the lock */
+ if (lock.l_type == F_UNLCK) {
+ adf_freelock(adf, i);
+ goto exit;
+ }
+
+ /* attempt to lock the file. */
+ if (set_lock(adf->adf_fd, F_SETLK, &lock) < 0) {
+ ret = -1;
+ goto exit;
+ }
+
+ /* we upgraded this lock. */
+ if (adflock && (type & ADLOCK_UPGRADE)) {
+ memcpy(&adflock->lock, &lock, sizeof(lock));
+ goto exit;
+ }
+
+ /* it wasn't an upgrade */
+ oldlock = -1;
+ if (lock.l_type == F_RDLCK) {
+ oldlock = adf_findxlock(adf, fork, ADLOCK_RD, lock.l_start, lock.l_len);
+ }
- /* no more space. this will also happen if lockmax == lockcount == 0 */
- if (adf->adf_lockmax == adf->adf_lockcount) {
- adf_lock_t *tmp = (adf_lock_t *)
- realloc(adf->adf_lock, sizeof(adf_lock_t)*
- (adf->adf_lockmax + ARRAY_BLOCK_SIZE));
- if (!tmp)
- goto fcntl_lock_err;
- adf->adf_lock = tmp;
- adf->adf_lockmax += ARRAY_BLOCK_SIZE;
- }
- adflock = adf->adf_lock + adf->adf_lockcount;
-
- /* fill in fields */
- memcpy(&adflock->lock, &lock, sizeof(lock));
- adflock->user = user;
- if (oldlock)
- adflock->refcount = oldlock->refcount;
- else if ((adflock->refcount = calloc(1, sizeof(int))) == NULL) {
- goto fcntl_lock_err;
- }
+ /* no more space. this will also happen if lockmax == lockcount == 0 */
+ if (adf->adf_lockmax == adf->adf_lockcount) {
+ adf_lock_t *tmp = (adf_lock_t *)
+ realloc(adf->adf_lock, sizeof(adf_lock_t)*
+ (adf->adf_lockmax + ARRAY_BLOCK_SIZE));
+ if (!tmp) {
+ ret = fcntl_lock_err = -1;
+ goto exit;
+ }
+ adf->adf_lock = tmp;
+ adf->adf_lockmax += ARRAY_BLOCK_SIZE;
+ }
+ adflock = adf->adf_lock + adf->adf_lockcount;
+
+ /* fill in fields */
+ memcpy(&adflock->lock, &lock, sizeof(lock));
+ adflock->user = fork;
+ if (oldlock > -1) {
+ adflock->refcount = (adf->adf_lock + oldlock)->refcount;
+ } else if ((adflock->refcount = calloc(1, sizeof(int))) == NULL) {
+ ret = fcntl_lock_err = 1;
+ goto exit;
+ }
- (*adflock->refcount)++;
- adf->adf_lockcount++;
- return 0;
-
-fcntl_lock_err:
- lock.l_type = F_UNLCK;
- fcntl(adf->adf_fd, F_SETLK, &lock);
- return -1;
+ (*adflock->refcount)++;
+ adf->adf_lockcount++;
+
+exit:
+ if (ret != 0) {
+ if (fcntl_lock_err != 0) {
+ lock.l_type = F_UNLCK;
+ set_lock(adf->adf_fd, F_SETLK, &lock);
+ }
+ }
+ LOG(log_debug, logtype_default, "ad_lock: END: %d", ret);
+ return ret;
}
-
-/* with temp locks, we don't need to distinguish within the same
- * process as everything is single-threaded. in addition, if
- * multi-threading gets added, it will only be in a few areas. */
-int ad_fcntl_tmplock(struct adouble *ad, const u_int32_t eid, const int type,
- const off_t off, const size_t len)
+int ad_tmplock(struct adouble *ad, uint32_t eid, int locktype, off_t off, off_t len, int fork)
{
- struct flock lock;
- struct ad_fd *adf;
- int err;
-
- lock.l_start = off;
- if (eid == ADEID_DFORK) {
- adf = &ad->ad_df;
- } else {
- adf = &ad->ad_hf;
- lock.l_start += ad_getentryoff(ad, eid);
- }
- lock.l_type = XLATE_FCNTL_LOCK(type & ADLOCK_MASK);
- lock.l_whence = SEEK_SET;
- lock.l_len = len;
-
- /* okay, we might have ranges byte-locked. we need to make sure that
- * we restore the appropriate ranges once we're done. so, we check
- * for overlap on an unlock and relock.
- * XXX: in the future, all the byte locks will be sorted and contiguous.
- * we just want to upgrade all the locks and then downgrade them
- * here. */
- err = fcntl(adf->adf_fd, F_SETLK, &lock);
- if (!err && (lock.l_type == F_UNLCK))
- adf_relockrange(adf, adf->adf_fd, lock.l_start, len);
-
- return err;
-}
+ struct flock lock;
+ struct ad_fd *adf;
+ int err;
+ int type;
+
+ LOG(log_debug, logtype_default, "ad_tmplock(%s, %s, off: %jd (%s), len: %jd): BEGIN",
+ eid == ADEID_DFORK ? "data" : "reso",
+ locktypetostr(locktype),
+ (intmax_t)off,
+ shmdstrfromoff(off),
+ (intmax_t)len);
+
+ lock.l_start = off;
+ type = locktype;
+
+ if (eid == ADEID_DFORK) {
+ adf = &ad->ad_data_fork;
+ } else {
+ adf = &ad->ad_resource_fork;
+ if (adf->adf_fd == -1) {
+ /* there's no resource fork. return success */
+ err = 0;
+ goto exit;
+ }
+ /* if ADLOCK_FILELOCK we want a lock from offset 0
+ * it's used when deleting a file:
+ * in open we put read locks on meta datas
+ * in delete a write locks on the whole file
+ * so if the file is open by somebody else it fails
+ */
+ if (!(type & ADLOCK_FILELOCK))
+ lock.l_start += ad_getentryoff(ad, eid);
+ }
+
+ if (!(adf->adf_flags & O_RDWR) && (type & ADLOCK_WR)) {
+ type = (type & ~ADLOCK_WR) | ADLOCK_RD;
+ }
+
+ lock.l_type = XLATE_FCNTL_LOCK(type & ADLOCK_MASK);
+ lock.l_whence = SEEK_SET;
+ lock.l_len = len;
+
+ /* see if it's locked by another fork. */
+ if (fork && adf_findxlock(adf, fork,
+ ADLOCK_WR | ((type & ADLOCK_WR) ? ADLOCK_RD : 0),
+ lock.l_start, lock.l_len) > -1) {
+ errno = EACCES;
+ err = -1;
+ goto exit;
+ }
+ /* okay, we might have ranges byte-locked. we need to make sure that
+ * we restore the appropriate ranges once we're done. so, we check
+ * for overlap on an unlock and relock.
+ * XXX: in the future, all the byte locks will be sorted and contiguous.
+ * we just want to upgrade all the locks and then downgrade them
+ * here. */
+ err = set_lock(adf->adf_fd, F_SETLK, &lock);
+ if (!err && (lock.l_type == F_UNLCK))
+ adf_relockrange(adf, adf->adf_fd, lock.l_start, len);
+
+exit:
+ LOG(log_debug, logtype_default, "ad_tmplock: END: %d", err);
+ return err;
+}
-void ad_fcntl_unlock(struct adouble *ad, const int user)
+/* --------------------- */
+void ad_unlock(struct adouble *ad, const int fork, int unlckbrl)
{
- if (ad->ad_df.adf_fd != -1) {
- adf_unlock(&ad->ad_df, ad->ad_df.adf_fd, user);
- }
- if (ad->ad_hf.adf_fd != -1) {
- adf_unlock(&ad->ad_hf, ad->ad_hf.adf_fd, user);
- }
+ LOG(log_debug, logtype_default, "ad_unlock(unlckbrl: %d): BEGIN", unlckbrl);
+
+ if (ad_data_fileno(ad) != -1) {
+ adf_unlock(ad, &ad->ad_data_fork, fork, unlckbrl);
+ }
+ if (ad_reso_fileno(ad) != -1) {
+ adf_unlock(ad, &ad->ad_resource_fork, fork, unlckbrl);
+ }
+
+ LOG(log_debug, logtype_default, "ad_unlock: END");
}
-/* byte-range locks. ad_lock is used by afp_bytelock and afp_openfork
- * to establish locks. both ad_lock and ad_tmplock take 0, 0, 0 to
- * signify locking of the entire file. in the absence of working
- * byte-range locks, this will default to file-wide flock-style locks.
+/*!
+ * Test for a share mode lock
+ *
+ * @param ad (rw) handle
+ * @param eid (r) datafork or ressource fork
+ * @param off (r) sharemode lock to test
+ *
+ * @returns 1 if there's an existing lock, 0 if there's no lock,
+ * -1 in case any error occured
*/
-int ad_flock_lock(struct adouble *ad, const u_int32_t eid, const int type,
- const off_t off, const size_t len, const int user)
+int ad_testlock(struct adouble *ad, int eid, const off_t off)
{
- int err, lock_type;
-
- lock_type = XLATE_FLOCK(type & ADLOCK_MASK);
- if (eid == ADEID_DFORK) {
- if ((err = flock(ad_dfileno(ad), lock_type | LOCK_NB)) == 0)
- ad->ad_df.adf_lockcount = lock_type;
- } else if ((err = flock(ad_hfileno(ad), lock_type | LOCK_NB)) == 0)
- ad->ad_hf.adf_lockcount = lock_type;
-
- if (err) {
- if ((EWOULDBLOCK != EAGAIN) && (errno == EWOULDBLOCK))
- errno = EAGAIN;
- return -1;
- }
+ int ret = 0;
+ off_t lock_offset;
+
+ LOG(log_debug, logtype_default, "ad_testlock(%s, off: %jd (%s): BEGIN",
+ eid == ADEID_DFORK ? "data" : "reso",
+ (intmax_t)off,
+ shmdstrfromoff(off));
+
+ if (eid == ADEID_DFORK) {
+ lock_offset = off;
+ } else { /* rfork */
+ lock_offset = rf2off(off);
+ }
+
+ ret = testlock(&ad->ad_data_fork, lock_offset, 1);
- return 0;
+ LOG(log_debug, logtype_default, "ad_testlock: END: %d", ret);
+ return ret;
}
-/* ad_tmplock is used by afpd to lock actual read/write operations.
- * it saves the current lock state before attempting to lock to prevent
- * mixups. if byte-locks don't exist, it will lock the entire file with
- * an flock. we can be a little smart here by just upgrading/downgrading
- * locks. */
-int ad_flock_tmplock(struct adouble *ad, const u_int32_t eid, const int type,
- const off_t off, const size_t len)
+/*!
+ * Return if a file is open by another process.
+ *
+ * Optimized for the common case:
+ * - there's no locks held by another process (clients)
+ * - or we already know the answer and don't need to test (attrbits)
+ *
+ * @param ad (rw) handle
+ * @param attrbits (r) forks opened by us
+ * @returns bitflags ATTRBIT_DOPEN | ATTRBIT_ROPEN if
+ * other process has fork of file opened
+ */
+uint16_t ad_openforks(struct adouble *ad, uint16_t attrbits)
{
- int fd, oldlock, lock_type;
-
- if (eid == ADEID_DFORK) {
- oldlock = ad->ad_df.adf_lockcount;
- fd = ad_dfileno(ad);
- } else {
- oldlock = ad->ad_hf.adf_lockcount;
- fd = ad_hfileno(ad);
- }
-
- /* if we already have a write lock, we don't need to do anything */
- if (oldlock == LOCK_EX) {
- return 0;
- }
+ uint16_t ret = 0;
+ struct ad_fd *adf;
+ off_t off;
+ off_t len;
+
+ if (ad_data_fileno(ad) == -1)
+ return 0;
+
+ if (!(attrbits & (ATTRBIT_DOPEN | ATTRBIT_ROPEN))) {
+ /* Test all 4 locks at once */
+ off = AD_FILELOCK_OPEN_WR;
+ len = 4;
+ if (testlock(&ad->ad_data_fork, off, len) == 0)
+ return 0;
+ }
- /* if we have a read lock, upgrade it if necessary */
- lock_type = XLATE_FLOCK(type & ADLOCK_MASK);
- if (oldlock == LOCK_SH) {
- if (lock_type == LOCK_EX)
- return flock(fd, LOCK_EX | LOCK_NB);
- else if (lock_type == LOCK_UN) /* reset it */
- return flock(fd, LOCK_SH | LOCK_NB);
- else /* do nothing */
- return 0;
- }
+ /* either there's a lock or we already know one fork is open */
- /* if we don't already have a lock, just do it. */
- return flock(fd, lock_type | LOCK_NB);
-}
+ if (!(attrbits & ATTRBIT_DOPEN)) {
+ off = AD_FILELOCK_OPEN_WR;
+ ret = testlock(&ad->ad_data_fork, off, 2) > 0 ? ATTRBIT_DOPEN : 0;
+ }
+ if (!(attrbits & ATTRBIT_ROPEN)) {
+ off = AD_FILELOCK_RSRC_OPEN_WR;
+ ret |= testlock(&ad->ad_data_fork, off, 2) > 0? ATTRBIT_ROPEN : 0;
+ }
+ return ret;
+}
projects / netatalk.git / blobdiff