[TD-2705] fix: provide cmdline info when a shutdown signal received.

src/dnode/src/dnodeSystem.c

@@ -160,7 +160,7 @@ static void signal_handler(int32_t signum, siginfo_t *sigInfo, void *context) {
   syslog(LOG_INFO, "Shut down signal is %d", signum);
   syslog(LOG_INFO, "Shutting down TDengine service...");
   // clean the system.
-  dInfo("shut down signal is %d, sender PID:%d", signum, sigInfo->si_pid);
+  dInfo("shut down signal is %d, sender PID:%d cmdline:%s", signum, sigInfo->si_pid, taosGetCmdlineByPID(sigInfo->si_pid));
 
   // protect the application from receive another signal
   struct sigaction act = {{0}};

src/os/inc/osSysinfo.h

@@ -32,6 +32,7 @@ void taosPrintOsInfo();
 int  taosSystem(const char * cmd) ;
 void taosKillSystem();
 bool taosGetSystemUid(char *uid);
+char *taosGetCmdlineByPID(int pid);
 
 // TAOS_OS_FUNC_SYSINFO_CORE
 void taosSetCoreDump();

src/os/src/linux/linuxEnv.c

@@ -40,3 +40,21 @@ void osInit() {
   strcpy(tsMnodeDir, "");
   strcpy(tsOsName, "Linux");
 }
+
+char cmdline[1024];
+
+char *taosGetCmdlineByPID(int pid)
+{
+  sprintf(cmdline, "/proc/%d/cmdline",pid);
+  FILE* f = fopen(cmdline,"r");
+  if(f){
+    size_t size;
+    size = fread(cmdline, sizeof(char), 1024, f);
+    if(size>0){
+      if('\n'==cmdline[size-1])
+        cmdline[size-1]='\0';
+    }
+    fclose(f);
+  }
+  return cmdline;
+}