X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=ustd%2Fustd.c;h=f3285f58ba534d8c82c7f80677f5eba5f32de85d;hb=d6322067aa791234d0d81e1a6b03b445635d5f65;hp=7882e34544278f4cd68a08303670e8b8d35d75ea;hpb=2ddb81a86943f0ca84b92ae4a1cf144098a9d8bd;p=ust.git

diff --git a/ustd/ustd.c b/ustd/ustd.c
index 7882e34..f3285f5 100644
--- a/ustd/ustd.c
+++ b/ustd/ustd.c
@@ -260,6 +260,9 @@ struct buffer_info *connect_buffer(pid_t pid, const char *bufname)
 		ERR("problem in ustcomm_send_request(get_pidunique)");
 		return NULL;
 	}
+	if(result == 0) {
+		goto error;
+	}
 
 	result = sscanf(received_msg, "%lld", &buf->pidunique);
 	if(result != 1) {
@@ -277,6 +280,9 @@ struct buffer_info *connect_buffer(pid_t pid, const char *bufname)
 		ERR("problem in ustcomm_send_request(get_shmid)");
 		return NULL;
 	}
+	if(result == 0) {
+		goto error;
+	}
 
 	result = sscanf(received_msg, "%d %d", &buf->shmid, &buf->bufstruct_shmid);
 	if(result != 2) {
@@ -294,6 +300,9 @@ struct buffer_info *connect_buffer(pid_t pid, const char *bufname)
 		ERR("problem in ustcomm_send_request(g_n_subbufs)");
 		return NULL;
 	}
+	if(result == 0) {
+		goto error;
+	}
 
 	result = sscanf(received_msg, "%d", &buf->n_subbufs);
 	if(result != 1) {
@@ -305,8 +314,15 @@ struct buffer_info *connect_buffer(pid_t pid, const char *bufname)
 
 	/* get subbuf size */
 	asprintf(&send_msg, "get_subbuf_size %s", buf->name);
-	ustcomm_send_request(&buf->conn, send_msg, &received_msg);
+	result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
 	free(send_msg);
+	if(result == -1) {
+		ERR("problem in ustcomm_send_request(get_subbuf_size)");
+		return NULL;
+	}
+	if(result == 0) {
+		goto error;
+	}
 
 	result = sscanf(received_msg, "%d", &buf->subbuf_size);
 	if(result != 1) {
@@ -378,6 +394,29 @@ struct buffer_info *connect_buffer(pid_t pid, const char *bufname)
 	pthread_mutex_unlock(&active_buffers_mutex);
 
 	return buf;
+
+error:
+	free(buf);
+	return NULL;
+}
+
+int unwrite_last_subbuffer(struct buffer_info *buf)
+{
+	int result;
+
+	result = ftruncate(buf->file_fd, buf->previous_offset);
+	if(result == -1) {
+		PERROR("ftruncate");
+		return -1;
+	}
+
+	result = lseek(buf->file_fd, buf->previous_offset, SEEK_SET);
+	if(result == (int)(off_t)-1) {
+		PERROR("lseek");
+		return -1;
+	}
+
+	return 0;
 }
 
 int write_current_subbuffer(struct buffer_info *buf)
@@ -388,11 +427,20 @@ int write_current_subbuffer(struct buffer_info *buf)
 
 	size_t cur_sb_size = subbuffer_data_size(subbuf_mem);
 
+	off_t cur_offset = lseek(buf->file_fd, 0, SEEK_CUR);
+	if(cur_offset == (off_t)-1) {
+		PERROR("lseek");
+		return -1;
+	}
+
+	buf->previous_offset = cur_offset;
+	DBG("previous_offset: %ld", cur_offset);
+
 	result = patient_write(buf->file_fd, subbuf_mem, cur_sb_size);
 	if(result == -1) {
 		PERROR("write");
 		/* FIXME: maybe drop this trace */
-		return 0;
+		return -1;
 	}
 
 	return 0;
@@ -425,7 +473,6 @@ int consumer_loop(struct buffer_info *buf)
 		/* FIXME: handle return value? */
 
 		/* put the subbuffer */
-		/* FIXME: we actually should unput the buffer before consuming... */
 		result = put_subbuffer(buf);
 		if(result == -1) {
 			ERR("unknown error putting subbuffer (channel=%s)", buf->name);
@@ -437,7 +484,10 @@ int consumer_loop(struct buffer_info *buf)
 		}
 		else if(result == PUT_SUBBUF_DIED) {
 			WARN("application died while putting subbuffer");
-			/* FIXME: probably need to skip the first subbuffer in finish_consuming_dead_subbuffer */
+			/* Skip the first subbuffer. We are not sure it is trustable
+			 * because the put_subbuffer() did not complete.
+			 */
+			unwrite_last_subbuffer(buf);
 			finish_consuming_dead_subbuffer(buf);
 			break;
 		}