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| author | Mathias Kresin <dev@kresin.me> | 2016-08-09 08:22:24 +0200 |
|---|---|---|
| committer | Felix Fietkau <nbd@nbd.name> | 2016-08-11 10:50:10 +0200 |
| commit | 5d0b180f798ca53cc04be4cec82c7c56b6c25d97 (patch) | |
| tree | e76a103ee9230021ea1c2a7ab1d5c2ad5a89daed /tools/flock/src | |
| parent | 360fd10ac9cb92425709c76ded0cd418662e121e (diff) | |
| download | upstream-5d0b180f798ca53cc04be4cec82c7c56b6c25d97.tar.gz upstream-5d0b180f798ca53cc04be4cec82c7c56b6c25d97.tar.bz2 upstream-5d0b180f798ca53cc04be4cec82c7c56b6c25d97.zip | |
tools: flock: add NFSv4 compatibility
This patch fixes the LEDE build on mounted NFSv4 shares.
The lock file cannot be opened in read-write mode by default, because
then we cannot use flock(1) to lock executable files.
The read-write mode for lock files is necessary on NFSv4 where
flock(2) is emulated by by fcntl() -- this situation is possible to
detect by flock(2) EBADF error.
The patch consist of the following util-linux/flock commits
http://git.kernel.org/cgit/utils/util-linux/util-linux.git/commit/?id=eb742a1f66d5e3a7c5b43efce741c113f51bef3b
http://git.kernel.org/cgit/utils/util-linux/util-linux.git/commit/?id=caf1ba11a367ad702fb774653daf9ebdcca49d7b
without including the pre kernel 3.4 support.
Signed-off-by: Mathias Kresin <dev@kresin.me>
Signed-off-by: Felix Fietkau <nbd@nbd.name> [minor cleanup]
Diffstat (limited to 'tools/flock/src')
| -rw-r--r-- | tools/flock/src/flock.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/tools/flock/src/flock.c b/tools/flock/src/flock.c index 3ac3a4bebc..37ab0ea72d 100644 --- a/tools/flock/src/flock.c +++ b/tools/flock/src/flock.c @@ -133,6 +133,7 @@ int main(int argc, char *argv[]) int do_close = 0; int err; int status; + int open_flags = 0; char *eon; char **cmd_argv = NULL, *sh_c_argv[4]; const char *filename = NULL; @@ -266,6 +267,21 @@ int main(int argc, char *argv[]) if ( timeout_expired ) exit(1); /* -w option set and failed to lock */ continue; /* otherwise try again */ + case EBADF: /* since Linux 3.4 (commit 55725513) */ + /* Probably NFSv4 where flock() is emulated by fcntl(). + * Let's try to reopen in read-write mode. + */ + if (!(open_flags & O_RDWR) && + type != LOCK_SH && + filename && + access(filename, R_OK | W_OK) == 0) { + + close(fd); + open_flags = O_RDWR; + fd = open(filename, open_flags); + break; + } + /* go through */ default: /* Other errors */ if ( filename ) fprintf(stderr, "%s: %s: %s\n", program, filename, strerror(err)); |