Add option to allow changing the location of or disabling the pidfile

1 files changed, 59 insertions, 37 deletions

diff --git a/src/main.c b/src/main.c
index c1d1edf..8702a4b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -54,7 +54,8 @@
 #include "conf.h"
 
 static const char *socket_path = "/var/run/usbmuxd";
-static const char *lockfile = "/var/run/usbmuxd.pid";
+#define DEFAULT_LOCKFILE "/var/run/usbmuxd.pid"
+static const char *lockfile = DEFAULT_LOCKFILE;
 
 // Global state used in other files
 int should_exit;
@@ -519,6 +520,8 @@ static void usage()
         printf("  -S, --socket ADDR:PORT | PATH   Specify source ADDR and PORT or a UNIX\n");
         printf("            \t\tsocket PATH to use for the listening socket.\n");
         printf("            \t\tDefault: %s\n", socket_path);
+        printf("  -P, --pidfile PATH\tSpecify a different location for the pid file, or pass\n");
+        printf("            \t\tNONE to disable. Default: %s\n", DEFAULT_LOCKFILE);
         printf("  -x, --exit\t\tNotify a running instance to exit if there are no devices\n");
         printf("            \t\tconnected (sends SIGUSR1 to running instance) and exit.\n");
         printf("  -X, --force-exit\tNotify a running instance to exit even if there are still\n");
@@ -547,6 +550,7 @@ static void parse_opts(int argc, char **argv)
                 {"systemd", no_argument, NULL, 's'},
 #endif
                 {"socket", required_argument, NULL, 'S'},
+                {"pidfile", required_argument, NULL, 'P'},
                 {"exit", no_argument, NULL, 'x'},
                 {"force-exit", no_argument, NULL, 'X'},
                 {"logfile", required_argument, NULL, 'l'},
@@ -556,11 +560,11 @@ static void parse_opts(int argc, char **argv)
         int c;
 
 #ifdef HAVE_SYSTEMD
-        const char* opts_spec = "hfvVuU:xXsnzl:pS:";
+        const char* opts_spec = "hfvVuU:xXsnzl:pS:P:";
 #elif HAVE_UDEV
-        const char* opts_spec = "hfvVuU:xXnzl:pS:";
+        const char* opts_spec = "hfvVuU:xXnzl:pS:P:";
 #else
-        const char* opts_spec = "hfvVU:xXnzl:pS:";
+        const char* opts_spec = "hfvVU:xXnzl:pS:P:";
 #endif
 
         while (1) {
@@ -615,6 +619,18 @@ static void parse_opts(int argc, char **argv)
                         }
                         listen_addr = optarg;
                         break;
+                case 'P':
+                        if (!*optarg || *optarg == '-') {
+                                usbmuxd_log(LL_FATAL, "ERROR: --pidfile requires an argument");
+                                usage();
+                                exit(2);
+                        }
+                        if (!strcmp(optarg, "NONE")) {
+                                lockfile = NULL;
+                        } else {
+                                lockfile = optarg;
+                        }
+                        break;
                 case 'x':
                         opt_exit = 1;
                         exit_signal = SIGUSR1;
@@ -676,19 +692,21 @@ int main(int argc, char *argv[])
         set_signal_handlers();
         signal(SIGPIPE, SIG_IGN);
 
-        res = lfd = open(lockfile, O_WRONLY|O_CREAT, 0644);
-        if(res == -1) {
-                usbmuxd_log(LL_FATAL, "Could not open lockfile");
-                goto terminate;
+        if (lockfile) {
+                res = lfd = open(lockfile, O_WRONLY|O_CREAT, 0644);
+                if(res == -1) {
+                        usbmuxd_log(LL_FATAL, "Could not open lockfile");
+                        goto terminate;
+                }
+                lock.l_type = F_WRLCK;
+                lock.l_whence = SEEK_SET;
+                lock.l_start = 0;
+                lock.l_len = 0;
+                lock.l_pid = 0;
+                fcntl(lfd, F_GETLK, &lock);
+                close(lfd);
         }
-        lock.l_type = F_WRLCK;
-        lock.l_whence = SEEK_SET;
-        lock.l_start = 0;
-        lock.l_len = 0;
-        lock.l_pid = 0;
-        fcntl(lfd, F_GETLK, &lock);
-        close(lfd);
-        if (lock.l_type != F_UNLCK) {
+        if (lockfile && lock.l_type != F_UNLCK) {
                 if (opt_exit) {
                         if (lock.l_pid && !kill(lock.l_pid, 0)) {
                                 usbmuxd_log(LL_NOTICE, "Sending signal %d to instance with pid %d", exit_signal, lock.l_pid);
@@ -724,7 +742,9 @@ int main(int argc, char *argv[])
                         goto terminate;
                 }
         }
-        unlink(lockfile);
+        if (lockfile) {
+                unlink(lockfile);
+        }
 
         if (opt_exit) {
                 usbmuxd_log(LL_NOTICE, "No running instance found, none killed. Exiting.");
@@ -739,26 +759,28 @@ int main(int argc, char *argv[])
                 }
         }
 
-        // now open the lockfile and place the lock
-        res = lfd = open(lockfile, O_WRONLY|O_CREAT|O_TRUNC|O_EXCL, 0644);
-        if(res < 0) {
-                usbmuxd_log(LL_FATAL, "Could not open lockfile");
-                goto terminate;
-        }
-        lock.l_type = F_WRLCK;
-        lock.l_whence = SEEK_SET;
-        lock.l_start = 0;
-        lock.l_len = 0;
-        if ((res = fcntl(lfd, F_SETLK, &lock)) < 0) {
-                usbmuxd_log(LL_FATAL, "Lockfile locking failed!");
-                goto terminate;
-        }
-        sprintf(pids, "%d", getpid());
-        if ((size_t)(res = write(lfd, pids, strlen(pids))) != strlen(pids)) {
-                usbmuxd_log(LL_FATAL, "Could not write pidfile!");
-                if(res >= 0)
-                        res = -2;
-                goto terminate;
+        if (lockfile) {
+                // now open the lockfile and place the lock
+                res = lfd = open(lockfile, O_WRONLY|O_CREAT|O_TRUNC|O_EXCL, 0644);
+                if(res < 0) {
+                        usbmuxd_log(LL_FATAL, "Could not open pidfile '%s'", lockfile);
+                        goto terminate;
+                }
+                lock.l_type = F_WRLCK;
+                lock.l_whence = SEEK_SET;
+                lock.l_start = 0;
+                lock.l_len = 0;
+                if ((res = fcntl(lfd, F_SETLK, &lock)) < 0) {
+                        usbmuxd_log(LL_FATAL, "Locking pidfile '%s' failed!", lockfile);
+                        goto terminate;
+                }
+                sprintf(pids, "%d", getpid());
+                if ((size_t)(res = write(lfd, pids, strlen(pids))) != strlen(pids)) {
+                        usbmuxd_log(LL_FATAL, "Could not write pidfile!");
+                        if(res >= 0)
+                                res = -2;
+                        goto terminate;
+                }
         }
 
         // set number of file descriptors to higher value