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lock-util: Use unposix_lock() in make_lock_file() and release_lock_file()

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This commit is contained in:
Daan De Meyer
2023-03-10 11:57:43 +01:00
parent 460accdf3d
commit 37c485482f
1 changed files with 8 additions and 15 deletions
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src/basic/lock-util.c
+8 -15
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@@ -18,8 +18,10 @@
int make_lock_file(const char *p, int operation, LockFile *ret) {
_cleanup_close_ int fd = -EBADF;
_cleanup_free_ char *t = NULL;
int r;
assert(p);
assert(IN_SET(operation & ~LOCK_NB, LOCK_EX, LOCK_SH));
assert(ret);
/* We use UNPOSIX locks as they have nice semantics, and are mostly compatible with NFS. */
@@ -29,18 +31,15 @@ int make_lock_file(const char *p, int operation, LockFile *ret) {
return -ENOMEM;
for (;;) {
struct flock fl = {
.l_type = (operation & ~LOCK_NB) == LOCK_EX ? F_WRLCK : F_RDLCK,
.l_whence = SEEK_SET,
};
struct stat st;
fd = open(p, O_CREAT|O_RDWR|O_NOFOLLOW|O_CLOEXEC|O_NOCTTY, 0600);
if (fd < 0)
return -errno;
if (fcntl(fd, (operation & LOCK_NB) ? F_OFD_SETLK : F_OFD_SETLKW, &fl) < 0)
return errno == EAGAIN ? -EBUSY : -errno;
r = unposix_lock(fd, operation);
if (r < 0)
return r == -EAGAIN ? -EBUSY : r;
/* If we acquired the lock, let's check if the file still exists in the file system. If not,
* then the previous exclusive owner removed it and then closed it. In such a case our
@@ -96,15 +95,9 @@ void release_lock_file(LockFile *f) {
* owner, we can try becoming it. */
if (f->fd >= 0 &&
(f->operation & ~LOCK_NB) == LOCK_SH) {
static const struct flock fl = {
.l_type = F_WRLCK,
.l_whence = SEEK_SET,
};
if (fcntl(f->fd, F_OFD_SETLK, &fl) >= 0)
f->operation = LOCK_EX|LOCK_NB;
}
(f->operation & ~LOCK_NB) == LOCK_SH &&
unposix_lock(f->fd, LOCK_EX|LOCK_NB) >= 0)
f->operation = LOCK_EX|LOCK_NB;
if ((f->operation & ~LOCK_NB) == LOCK_EX)
unlink_noerrno(f->path);