add ust_potential_exec, to prepare for execs

[ust.git] / libust / tracectl.c

diff --git a/libust/tracectl.c b/libust/tracectl.c
index a52b208f34b369a6887a59f5ce95da94d48a85d4..97c515cfa68dcbbf6227c263ebc2dd2714cd256f 100644 (file)
--- a/libust/tracectl.c
+++ b/libust/tracectl.c
@@ -46,6 +46,11 @@
 
 char consumer_stack[10000];
 
+/* This should only be accessed by the constructor, before the creation
+ * of the listener, and then only by the listener.
+ */
+s64 pidunique = -1LL;
+
 struct list_head blocked_consumers = LIST_HEAD_INIT(blocked_consumers);
 
 static struct ustcomm_app ustcomm_app;
@@ -93,6 +98,20 @@ struct blocked_consumer {
        struct list_head list;
 };
 
+static long long make_pidunique(void)
+{
+       s64 retval;
+       struct timeval tv;
+       
+       gettimeofday(&tv, NULL);
+
+       retval = tv.tv_sec;
+       retval <<= 32;
+       retval |= tv.tv_usec;
+
+       return retval;
+}
+
 static void print_markers(FILE *fp)
 {
        struct marker_iter iter;
@@ -682,6 +701,19 @@ void *listener_main(void *p)
                                WARN("could not disable marker; channel=%s, name=%s", channel_name, marker_name);
                        }
                }
+               else if(nth_token_is(recvbuf, "get_pidunique", 0) == 1) {
+                       char *reply;
+
+                       asprintf(&reply, "%lld", pidunique);
+
+                       result = ustcomm_send_reply(&ustcomm_app.server, reply, &src);
+                       if(result) {
+                               ERR("listener: get_pidunique: ustcomm_send_reply failed");
+                               goto next_cmd;
+                       }
+
+                       free(reply);
+               }
 //             else if(nth_token_is(recvbuf, "get_notifications", 0) == 1) {
 //                     struct ltt_trace_struct *trace;
 //                     char trace_name[] = "auto";
@@ -793,23 +825,6 @@ static int init_socket(void)
        return ustcomm_init_app(getpid(), &ustcomm_app);
 }
 
-/* FIXME: reenable this to delete socket file. */
-
-#if 0
-static void destroy_socket(void)
-{
-       int result;
-
-       if(mysocketfile[0] == '\0')
-               return;
-
-       result = unlink(mysocketfile);
-       if(result == -1) {
-               PERROR("unlink");
-       }
-}
-#endif
-
 static int init_signal_handler(void)
 {
        /* Attempt to handler SIGIO. If the main program wants to
@@ -884,6 +899,11 @@ static void __attribute__((constructor(1000))) init()
        int result;
        char* autoprobe_val = NULL;
 
+       /* Assign the pidunique, to be able to differentiate the processes with same
+        * pid, (before and after an exec).
+        */
+       pidunique = make_pidunique();
+
        /* Initialize RCU in case the constructor order is not good. */
        urcu_init();
 
@@ -1005,31 +1025,34 @@ static void __attribute__((constructor(1000))) init()
 }
 
 /* This is only called if we terminate normally, not with an unhandled signal,
- * so we cannot rely on it. */
+ * so we cannot rely on it. However, for now, LTTV requires that the header of
+ * the last sub-buffer contain a valid end time for the trace. This is done
+ * automatically only when the trace is properly stopped.
+ *
+ * If the traced program crashed, it is always possible to manually add the
+ * right value in the header, or to open the trace in text mode.
+ *
+ * FIXME: Fix LTTV so it doesn't need this.
+ */
 
-/* This destructor probably isn't needed, because ustd can do crash recovery. */
-#if 0
-static void __attribute__((destructor)) fini()
+static void destroy_traces(void)
 {
-//     int result;
+       int result;
 
        /* if trace running, finish it */
 
-//     DBG("destructor stopping traces");
+       DBG("destructor stopping traces");
 
-//     result = ltt_trace_stop("auto");
-//     if(result == -1) {
-//             ERR("ltt_trace_stop error");
-//     }
-//
-//     result = ltt_trace_destroy("auto");
-//     if(result == -1) {
-//             ERR("ltt_trace_destroy error");
-//     }
-//
-//     destroy_socket();
+       result = ltt_trace_stop("auto");
+       if(result == -1) {
+               ERR("ltt_trace_stop error");
+       }
+
+       result = ltt_trace_destroy("auto");
+       if(result == -1) {
+               ERR("ltt_trace_destroy error");
+       }
 }
-#endif
 
 static int trace_recording(void)
 {
@@ -1099,6 +1122,17 @@ static void __attribute__((destructor)) keepalive()
                }
                DBG("Finally dying...");
        }
+
+       destroy_traces();
+
+       ustcomm_fini_app(&ustcomm_app);
+}
+
+void ust_potential_exec(void)
+{
+       trace_mark(ust, potential_exec, MARK_NOARGS);
+
+       keepalive();
 }
 
 /* Notify ust that there was a fork. This needs to be called inside
@@ -1133,7 +1167,7 @@ void ust_fork(void)
        result = ltt_trace_set_type("auto", "ustrelay");
        if(result < 0) {
                ERR("ltt_trace_set_type failed");
-               return (void *)1;
+               return;
        }
 
        ltt_trace_alloc("auto");