The deamon currently does not have the ability to write a PID file to track its
process ID. This is very useful to an init script and to ensure there is only
one running instance. This patch implements this functionality.
Signed-off-by: Chris Boot <bootc@xxxxxxxxx>
---
src/ulogd.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 74 insertions(+), 1 deletion(-)
diff --git a/src/ulogd.c b/src/ulogd.c
index 8a144e3..982663f 100644
--- a/src/ulogd.c
+++ b/src/ulogd.c
@@ -4,6 +4,7 @@
*
* (C) 2000-2005 by Harald Welte <laforge@xxxxxxxxxxxx>
* (C) 2013 by Eric Leblond <eric@xxxxxxxxx>
+ * (C) 2013 Chris Boot <bootc@xxxxxxxxx>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
@@ -55,12 +56,14 @@
#include <signal.h>
#include <dlfcn.h>
#include <sys/types.h>
+#include <fcntl.h>
#include <dirent.h>
#include <getopt.h>
#include <pwd.h>
#include <grp.h>
#include <syslog.h>
#include <sys/time.h>
+#include <sys/stat.h>
#include <ulogd/conffile.h>
#include <ulogd/ulogd.h>
#ifdef DEBUG
@@ -78,6 +81,7 @@
static FILE *logfile = NULL; /* logfile pointer */
static char *ulogd_logfile = NULL;
static const char *ulogd_configfile = ULOGD_CONFIGFILE;
+static const char *ulogd_pidfile = NULL;
static FILE syslog_dummy;
static int info_mode = 0;
@@ -94,6 +98,7 @@ static LLIST_HEAD(ulogd_pi_stacks);
static int load_plugin(const char *file);
static int create_stack(const char *file);
static int logfile_open(const char *name);
+static void cleanup_pidfile();
static struct config_keyset ulogd_kset = {
.num_ces = 4,
@@ -457,6 +462,8 @@ void __ulogd_log(int level, char *file, int line, const char *format, ...)
static void warn_and_exit(int daemonize)
{
+ cleanup_pidfile();
+
if (!daemonize) {
if (logfile && !verbose) {
fprintf(stderr, "Fatal error, check logfile \"%s\""
@@ -1002,6 +1009,62 @@ static int parse_conffile(const char *section, struct config_keyset *ce)
return 1;
}
+static int write_pidfile()
+{
+ struct stat pid_st;
+ int pid_fp;
+ char pidtext[16];
+ int len;
+
+ if (!ulogd_pidfile)
+ return 0;
+
+ if (stat(ulogd_pidfile, &pid_st) == 0 || errno != ENOENT) {
+ ulogd_log(ULOGD_FATAL, "PID file %s exists, not starting\n",
+ ulogd_pidfile);
+ return -1;
+ }
+
+ pid_fp = open(ulogd_pidfile, O_WRONLY | O_CREAT | O_EXCL, 0644);
+ if (pid_fp < 0) {
+ ulogd_log(ULOGD_FATAL, "PID file %s could not be opened: %d\n",
+ ulogd_pidfile, errno);
+ return -1;
+ }
+
+ if (ftruncate(pid_fp, 0) != 0) {
+ close(pid_fp);
+ unlink(ulogd_pidfile);
+ ulogd_log(ULOGD_FATAL, "PID file %s could not be truncated: %d\n",
+ ulogd_pidfile, errno);
+ return -1;
+ }
+
+ len = snprintf(pidtext, sizeof(pidtext), "%ld\n", (long)getpid());
+
+ if (write(pid_fp, pidtext, len) != len) {
+ close(pid_fp);
+ unlink(ulogd_pidfile);
+ ulogd_log(ULOGD_FATAL, "PID file %s could not be written: %d\n",
+ ulogd_pidfile, errno);
+ return -1;
+ }
+
+ /* deliberately leave PID file open */
+
+ return 0;
+}
+
+static void cleanup_pidfile()
+{
+ if (!ulogd_pidfile)
+ return;
+
+ if (unlink(ulogd_pidfile) != 0)
+ ulogd_log(ULOGD_ERROR, "PID file %s could not be deleted: %d\n",
+ ulogd_pidfile, errno);
+}
+
static void deliver_signal_pluginstances(int signal)
{
struct ulogd_pluginstance_stack *stack;
@@ -1080,6 +1143,8 @@ static void sigterm_handler(int signal)
config_stop();
+ cleanup_pidfile();
+
exit(0);
}
@@ -1121,6 +1186,7 @@ static void print_usage(void)
printf("\t-v --verbose\tOutput info on standard output\n");
printf("\t-l --loglevel\tSet log level\n");
printf("\t-c --configfile\tUse alternative Configfile\n");
+ printf("\t-p --pidfile\tRecord ulogd PID in file\n");
printf("\t-u --uid\tChange UID/GID\n");
printf("\t-i --info\tDisplay infos about plugin\n");
}
@@ -1134,6 +1200,7 @@ static struct option opts[] = {
{ "info", 1, NULL, 'i' },
{ "verbose", 0, NULL, 'v' },
{ "loglevel", 1, NULL, 'l' },
+ { "pidfile", 1, NULL, 'p' },
{NULL, 0, NULL, 0}
};
@@ -1150,7 +1217,7 @@ int main(int argc, char* argv[])
ulogd_logfile = strdup(ULOGD_LOGFILE_DEFAULT);
- while ((argch = getopt_long(argc, argv, "c:dvl:h::Vu:i:", opts, NULL)) != -1) {
+ while ((argch = getopt_long(argc, argv, "c:p:dvl:h::Vu:i:", opts, NULL)) != -1) {
switch (argch) {
default:
case '?':
@@ -1179,6 +1246,9 @@ int main(int argc, char* argv[])
case 'c':
ulogd_configfile = optarg;
break;
+ case 'p':
+ ulogd_pidfile = optarg;
+ break;
case 'u':
change_uid = 1;
user = strdup(optarg);
@@ -1280,6 +1350,9 @@ int main(int argc, char* argv[])
setsid();
}
+ if (write_pidfile() < 0)
+ warn_and_exit(daemonize);
+
signal(SIGTERM, &sigterm_handler);
signal(SIGINT, &sigterm_handler);
signal(SIGHUP, &signal_handler);
--
1.7.10.4
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