usttrace: deal correctly with ustd creation and termination

[ust.git] / ustd / ustd.c

diff --git a/ustd/ustd.c b/ustd/ustd.c
index 001977660a6ec0c86d809ce4a0ccb298a638427b..858bdf52b46c9e21ac6bab46e358ff016c117505 100644 (file)
--- a/ustd/ustd.c
+++ b/ustd/ustd.c
@@ -53,6 +53,7 @@
 char *sock_path=NULL;
 char *trace_path=NULL;
 int daemon_mode = 0;
+char *pidfile = NULL;
 
 /* Number of active buffers and the mutex to protect it. */
 int active_buffers = 0;
@@ -516,6 +517,9 @@ int parse_args(int argc, char **argv)
                case 'd':
                        daemon_mode = 1;
                        break;
+               case 'p':
+                       pidfile = strdup(optarg);
+                       break;
                case 'h':
                        usage();
                        exit(0);
@@ -538,6 +542,24 @@ void sigterm_handler(int sig)
        terminate_req = 1;
 }
 
+static int write_pidfile(const char *file_name, pid_t pid)
+{
+       FILE *pidfp;
+
+       pidfp = fopen(file_name, "w+");
+       if(!pidfp) {
+               PERROR("fopen (%s)", pidfile);
+               WARN("killing child process");
+               return -1;
+       }
+
+       fprintf(pidfp, "%d\n", pid);
+
+       fclose(pidfp);
+
+       return 0;
+}
+
 int start_ustd(int fd)
 {
        struct ustcomm_ustd ustd;
@@ -582,6 +604,15 @@ int start_ustd(int fd)
                return 1;
        }
 
+       /* Write pidfile */
+       if(pidfile) {
+               result = write_pidfile(pidfile, getpid());
+               if(result == -1) {
+                       ERR("failed to write pidfile");
+                       return 1;
+               }
+       }
+
        /* Notify parent that we are successfully started. */
        if(fd != -1) {
                /* write any one character */
@@ -654,10 +685,11 @@ int start_ustd_daemon()
 {
        int result;
        int fd[2];
+       pid_t child_pid;
 
        result = pipe(fd);
 
-       result = fork();
+       result = child_pid = fork();
        if(result == -1) {
                PERROR("fork");
                return -1;
@@ -667,6 +699,7 @@ int start_ustd_daemon()
        }
        else {
                char buf;
+               FILE *pidfp;
 
                result = read(fd[0], &buf, 1);
                if(result == -1) {