From: Pierre-Marc Fournier <pierre-marc.fournier@polymtl.ca>
Date: Fri, 25 Sep 2009 19:14:52 +0000 (-0400)
Subject: add pidunique concept
X-Git-Tag: v0.1~127
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=ed1317e78616d3fb99791d4effef7473317c41ec;p=ust.git

add pidunique concept
---

diff --git a/libust/tracectl.c b/libust/tracectl.c
index ee67daa..1dd7162 100644
--- 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";
@@ -867,6 +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();
 
diff --git a/ustd/ustd.c b/ustd/ustd.c
index fdf8d13..ddbb18b 100644
--- a/ustd/ustd.c
+++ b/ustd/ustd.c
@@ -326,6 +326,23 @@ int add_buffer(pid_t pid, char *bufname)
 		return -1;
 	}
 
+	/* get pidunique */
+	asprintf(&send_msg, "get_pidunique");
+	result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
+	free(send_msg);
+	if(result == -1) {
+		ERR("problem in ustcomm_send_request(get_pidunique)");
+		return -1;
+	}
+
+	result = sscanf(received_msg, "%lld", &buf->pidunique);
+	if(result != 1) {
+		ERR("unable to parse response to get_pidunique");
+		return -1;
+	}
+	free(received_msg);
+	DBG("got pidunique %lld", buf->pidunique);
+
 	/* get shmid */
 	asprintf(&send_msg, "get_shmid %s", buf->name);
 	result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
@@ -411,7 +428,7 @@ int add_buffer(pid_t pid, char *bufname)
 		trace_path = USTD_DEFAULT_TRACE_PATH;
 	}
 
-	asprintf(&tmp, "%s/%u", trace_path, buf->pid);
+	asprintf(&tmp, "%s/%u_%lld", trace_path, buf->pid, buf->pidunique);
 	result = create_dir_if_needed(tmp);
 	if(result == -1) {
 		ERR("could not create directory %s", tmp);
@@ -420,8 +437,8 @@ int add_buffer(pid_t pid, char *bufname)
 	}
 	free(tmp);
 
-	asprintf(&tmp, "%s/%u/%s_0", trace_path, buf->pid, buf->name);
-	result = fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 00600);
+	asprintf(&tmp, "%s/%u_%lld/%s_0", trace_path, buf->pid, buf->pidunique, buf->name);
+	result = fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, 00600);
 	if(result == -1) {
 		PERROR("open");
 		ERR("failed opening trace file %s", tmp);
diff --git a/ustd/ustd.h b/ustd/ustd.h
index 0b2db77..65328d6 100644
--- a/ustd/ustd.h
+++ b/ustd/ustd.h
@@ -28,6 +28,8 @@ struct buffer_info {
 	int file_fd; /* output file */
 
 	long consumed_old;
+
+	s64 pidunique;
 };
 
 ssize_t patient_write(int fd, const void *buf, size_t count);