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daemon: Avoid redundant code in already_running().

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This function substantially duplicated read_pidfile(), so reuse that
code instead.
This commit is contained in:
Ben Pfaff
2011-03-29 09:44:55 -07:00
parent 2159de8391
commit 18e124a20b
3 changed files with 48 additions and 60 deletions
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59
lib/daemon.c
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@@ -139,37 +139,17 @@ daemon_set_monitor(void)
monitor = true;
}
/* If a pidfile has been configured and that pidfile already exists and is
* locked by a running process, returns the pid of the running process.
* Otherwise, returns 0. */
static pid_t
already_running(void)
{
pid_t pid = 0;
if (pidfile) {
int fd = open(pidfile, O_RDWR);
if (fd >= 0) {
struct flock lck;
lck.l_type = F_WRLCK;
lck.l_whence = SEEK_SET;
lck.l_start = 0;
lck.l_len = 0;
if (fcntl(fd, F_GETLK, &lck) != -1 && lck.l_type != F_UNLCK) {
pid = lck.l_pid;
}
close(fd);
}
}
return pid;
}
/* If a locked pidfile exists, issue a warning message and, unless
* ignore_existing_pidfile() has been called, terminate the program. */
void
die_if_already_running(void)
{
pid_t pid = already_running();
if (pid) {
pid_t pid;
if (!pidfile) {
return;
}
pid = read_pidfile_if_exists(pidfile);
if (pid > 0) {
if (!overwrite_pidfile) {
VLOG_ERR("%s: %s already running as pid %ld, aborting",
get_pidfile(), program_name, (long int) pid);
@@ -509,10 +489,8 @@ daemon_usage(void)
ovs_rundir(), program_name);
}
/* Opens and reads a PID from 'pidfile'. Returns the nonnegative PID if
* successful, otherwise a negative errno value. */
pid_t
read_pidfile(const char *pidfile)
static pid_t
read_pidfile__(const char *pidfile, bool must_exist)
{
char line[128];
struct flock lck;
@@ -533,6 +511,9 @@ read_pidfile(const char *pidfile)
file = fopen(pidfile, "r");
if (!file) {
if (errno == ENOENT && !must_exist) {
return 0;
}
error = errno;
VLOG_WARN("%s: open: %s", pidfile, strerror(error));
goto error;
@@ -581,3 +562,21 @@ error:
}
return -error;
}
/* Opens and reads a PID from 'pidfile'. Returns the positive PID if
* successful, otherwise a negative errno value. */
pid_t
read_pidfile(const char *pidfile)
{
return read_pidfile__(pidfile, true);
}
/* Opens and reads a PID from 'pidfile', if it exists. Returns 0 if 'pidfile'
* doesn't exist, the positive PID if successful, otherwise a negative errno
* value. */
pid_t
read_pidfile_if_exists(const char *pidfile)
{
return read_pidfile__(pidfile, false);
}