Remove one-instance-lock mechanism

This commit removes DLT's "one-instance-lock" mechanism.
In daemonized mode, on first instance, a file is created (if not
already created) and locked. If second instance is attempted
file locking fails since the file is already locked by first instance.
This prevents new instance of the DLT daemon. After analysis
its found that there is no need of any mechanism for prevention
of another instance. The same is already taken care by socket
mechanism. Since main socket is created by first instance, attempt
to create it again with same port number fails.

Signed-off-by: Jeevan Ramakant Nagvekar <jeevan.nagvekar1@wipro.com>

2 files changed, 1 insertions, 36 deletions

diff --git a/src/daemon/dlt-daemon.c b/src/daemon/dlt-daemon.c
index 5c65613..660932c 100644
--- a/src/daemon/dlt-daemon.c
+++ b/src/daemon/dlt-daemon.c
@@ -1338,9 +1338,6 @@ void dlt_daemon_local_cleanup(DltDaemon *daemon, DltDaemonLocal *daemon_local, i
     dlt_shm_free_server(&(daemon_local->dlt_shm));
 #endif
 
-    /* Try to delete lock file, ignore result of unlink() */
-    unlink(DLT_DAEMON_LOCK_FILE);
-
     if (daemon_local->flags.offlineLogstorageMaxDevices > 0)
     {
         /* disconnect all logstorage devices */
@@ -1367,9 +1364,6 @@ void dlt_daemon_exit_trigger()
     snprintf(tmp, PATH_MAX, "%s/dlt", dltFifoBaseDir);
     (void)unlink(tmp);
 
-    snprintf(tmp, PATH_MAX, "%s/%s", dltFifoBaseDir, DLT_DAEMON_LOCK_FILE);
-    (void)unlink(tmp);
-
     /* stop event loop */
     g_exit = -1;
 }
@@ -1400,8 +1394,7 @@ void dlt_daemon_signal_handler(int sig)
 
 void dlt_daemon_daemonize(int verbose)
 {
-    int i,lfp;
-    ssize_t pid_len;
+    int i;
 
     PRINT_FUNCTION_VERBOSE(verbose);
 
@@ -1456,29 +1449,6 @@ void dlt_daemon_daemonize(int verbose)
         dlt_log(LOG_WARNING, str);
     }
 
-    /* Ensure single copy of daemon; if started with same directory
-       run only one instance at a time */
-    char dlt_daemon_lock_file[PATH_MAX + 1];
-    snprintf(dlt_daemon_lock_file, PATH_MAX, "%s/%s", dltFifoBaseDir, DLT_DAEMON_LOCK_FILE);
-    dlt_daemon_lock_file[PATH_MAX] = 0;
-    lfp=open(dlt_daemon_lock_file,O_RDWR|O_CREAT,DLT_DAEMON_LOCK_FILE_PERM);
-    if (lfp<0)
-    {
-        dlt_log(LOG_CRIT, "Can't open lock file, exiting DLT daemon\n");
-        exit(-1); /* can not open */
-    }
-    if (lockf(lfp,F_TLOCK,0)<0)
-    {
-        dlt_log(LOG_CRIT, "Can't lock lock file, exiting DLT daemon\n");
-        exit(-1); /* can not lock */
-    }
-    /* only first instance continues */
-
-    snprintf(str,DLT_DAEMON_TEXTBUFSIZE,"%d\n",getpid());
-    pid_len = strlen(str);
-    if(write(lfp,str,pid_len) != pid_len) /* record pid to lockfile */
-        dlt_log(LOG_WARNING, "Could not write pid to file in dlt_daemon_daemonize.\n");
-
     /* Catch signals */
     signal(SIGCHLD,SIG_IGN); /* ignore child */
     signal(SIGTSTP,SIG_IGN); /* ignore tty signals */
diff --git a/src/daemon/dlt-daemon_cfg.h b/src/daemon/dlt-daemon_cfg.h
index 8870217..ff3a042 100644
--- a/src/daemon/dlt-daemon_cfg.h
+++ b/src/daemon/dlt-daemon_cfg.h
@@ -94,13 +94,8 @@
 /* Maximum length of a description */
 #define DLT_DAEMON_DESCSIZE           256
 
-/* Name of daemon lock file, contain process id of dlt daemon instance */
-#define DLT_DAEMON_LOCK_FILE  "dltd.lock"
-
 /* Umask of daemon, creates files with permission 750 */
 #define DLT_DAEMON_UMASK              027
-/* Permissions of daemon lock file */
-#define DLT_DAEMON_LOCK_FILE_PERM    0640
 
 /* Default ECU ID, used in storage header and transmitted to client*/
 #define DLT_DAEMON_ECU_ID "ECU1"