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| author | Duncan Overbruck <mail@duncano.de> | 2021-03-01 00:45:04 +0100 |
|---|---|---|
| committer | Leah Neukirchen <leah@vuxu.org> | 2021-03-13 16:27:55 +0100 |
| commit | 8cf40887c7b68f0772a46080fb265e67c7f43b36 (patch) | |
| tree | b486025699f72f1dbe8b5edf91e944d03861a350 | |
| parent | 1d402f5fbbfd74be8369765ed8b4d8f664ba4996 (diff) | |
| download | nq-8cf40887c7b68f0772a46080fb265e67c7f43b36.tar.gz nq-8cf40887c7b68f0772a46080fb265e67c7f43b36.tar.xz nq-8cf40887c7b68f0772a46080fb265e67c7f43b36.zip | |
nq: use shared locks when waiting for other lockfiles
The nq process itself will hold an exclusive lock on its lock file, the other nq processes will now use a shared lock to test if the previous queue item is still locked. By using shared locks, multiple nq processes testing the same shared lock don't interfere with other nq processes checking for locks.
| -rw-r--r-- | nq.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/nq.c b/nq.c index 5fe69bf..8043fe5 100644 --- a/nq.c +++ b/nq.c @@ -285,11 +285,11 @@ wait: if (fd < 0) continue; - if (flock(fd, LOCK_EX | LOCK_NB) == -1 && + if (flock(fd, LOCK_SH | LOCK_NB) == -1 && errno == EWOULDBLOCK) { if (tflag) exit(1); - flock(fd, LOCK_EX); /* sit it out. */ + flock(fd, LOCK_SH); /* sit it out. */ } fchmod(fd, 0600); @@ -317,7 +317,7 @@ again: if (fd < 0) continue; - if (flock(fd, LOCK_EX | LOCK_NB) == -1 && + if (flock(fd, LOCK_SH | LOCK_NB) == -1 && errno == EWOULDBLOCK) { if (tflag) exit(1); @@ -333,7 +333,7 @@ again: if (*newestlocked) { int fd = openat(dirfd, newestlocked, O_RDWR); if (fd >= 0) { - flock(fd, LOCK_EX); /* sit it out. */ + flock(fd, LOCK_SH); /* sit it out. */ close(fd); } rewinddir(dir); |