| Patrick Williams | c124f4f | 2015-09-15 14:41:29 -0500 | [diff] [blame] | 1 | daemon.c: Fix race window for writing of the pid file |
| 2 | |
| 3 | The parent process should write the pid file such that the pid file |
| 4 | will can be checked immediately following exit of the fork from the |
| 5 | parent. |
| 6 | |
| 7 | This allows external monitoring applications to watch the daemon |
| 8 | without having to add sleep calls to wait for the pid file be written |
| 9 | on a busy system. |
| 10 | |
| 11 | Signed-off-by: Jason Wessel <jason.wessel@windriver.com> |
| 12 | |
| 13 | Upstream-Status: Submitted http://sourceforge.net/p/unfs3/bugs/5/ |
| 14 | |
| 15 | --- |
| 16 | daemon.c | 12 +++++++++--- |
| 17 | 1 file changed, 9 insertions(+), 3 deletions(-) |
| 18 | |
| 19 | --- a/daemon.c |
| 20 | +++ b/daemon.c |
| 21 | @@ -153,7 +153,7 @@ int get_socket_type(struct svc_req *rqst |
| 22 | /* |
| 23 | * write current pid to a file |
| 24 | */ |
| 25 | -static void create_pid_file(void) |
| 26 | +static void create_pid_file(int pid) |
| 27 | { |
| 28 | char buf[16]; |
| 29 | int fd, res, len; |
| 30 | @@ -175,7 +175,7 @@ static void create_pid_file(void) |
| 31 | } |
| 32 | #endif |
| 33 | |
| 34 | - sprintf(buf, "%i\n", backend_getpid()); |
| 35 | + sprintf(buf, "%i\n", pid); |
| 36 | len = strlen(buf); |
| 37 | |
| 38 | res = backend_pwrite(fd, buf, len, 0); |
| 39 | @@ -970,6 +970,10 @@ int main(int argc, char **argv) |
| 40 | fprintf(stderr, "could not fork into background\n"); |
| 41 | daemon_exit(0); |
| 42 | } |
| 43 | + if (pid) |
| 44 | + create_pid_file(pid); |
| 45 | + } else { |
| 46 | + create_pid_file(backend_getpid()); |
| 47 | } |
| 48 | #endif /* WIN32 */ |
| 49 | |
| 50 | @@ -1006,8 +1010,10 @@ int main(int argc, char **argv) |
| 51 | /* no umask to not screw up create modes */ |
| 52 | umask(0); |
| 53 | |
| 54 | +#ifdef WIN32 |
| 55 | /* create pid file if wanted */ |
| 56 | - create_pid_file(); |
| 57 | + create_pid_file(backend_getpid()); |
| 58 | +#endif |
| 59 | |
| 60 | /* initialize internal stuff */ |
| 61 | fh_cache_init(); |