[lttng-dev] [PATCH] lttng-tools lttng commands add_context.c : Return values of the cmd_add_context() chain of functions

[Thibault, Daniel]

Document and ensure the return values of the cmd_add_context() chain of functions.
Make add_context() stop looping over lttng_add_context() upon failure (otherwise it reports success or failure depending only on the last call's result).
Also patches lib/lttng-ctl/lttng-ctl.c
------------------------------
>From 9de81398942fe0adeb5288483ecb70e2573e69f0 Thu, 26 Jan 2012 16:23:05 -0500
From: Daniel U. Thibault <daniel.thibault at drdc-rddc.gc.ca>
Date: Thu, 26 Jan 2012 16:22:54 -0500
Subject: [PATCH] lttng-tools lttng commands add_context.c : Return values of the cmd_add_context() chain of functions

diff --git a/src/bin/lttng/commands/add_context.c b/src/bin/lttng/commands/add_context.c
index d0f5b6f..1c63d90 100644
--- a/src/bin/lttng/commands/add_context.c
+++ b/src/bin/lttng/commands/add_context.c
@@ -358,6 +358,7 @@
 
 /*
  * Add context to channel or event.
+ * Returns one of the CMD_* result constants.
  */
 static int add_context(char *session_name)
 {
@@ -379,7 +380,7 @@
 
 	handle = lttng_create_handle(session_name, &dom);
 	if (handle == NULL) {
-		ret = -1;
+		ret = CMD_ERROR;
 		goto error;
 	}
 
@@ -400,11 +401,17 @@
 		}
 		DBG("Adding context...");
 
+		/*
+		 * lttng_add_context() returns the size
+		 * of the returned payload data
+		 * or a negative error code.
+		 */
 		ret = lttng_add_context(handle, &context, opt_event_name,
 				opt_channel_name);
+		/* Stop looping upon error */
 		if (ret < 0) {
 			fprintf(stderr, "%s: ", type->opt->symbol);
-			continue;
+			goto error;
 		} else {
 			MSG("%s context %s added to %s event in %s",
 					opt_kernel ? "kernel" : "UST", type->opt->symbol,
@@ -412,7 +419,8 @@
 					opt_channel_name ? opt_channel_name : "all channels");
 		}
 	}
-
+	/* Normalise return code upon success */
+	ret = CMD_SUCCESS;
 error:
 	lttng_destroy_handle(handle);
 
@@ -421,6 +429,7 @@
 
 /*
  * Add context to channel or event.
+ * Returns one of the CMD_* result constants.
  */
 int cmd_add_context(int argc, const char **argv)
 {
@@ -445,8 +454,10 @@
 			ret = CMD_SUCCESS;
 			goto end;
 		case OPT_TYPE:
-			//Look up the index of opt_type in ctx_opts[] first,
-			//so we don't have to free(type) on failure
+			/*
+			 * Look up the index of opt_type in ctx_opts[] first,
+			 * so we don't have to free(type) on failure
+			 */
 			index = find_ctx_type_idx(opt_type);
 			if (index < 0) {
 				ERR("Unknown context type %s", opt_type);
diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index e7ebab5..ebb76ec 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -462,6 +462,7 @@
 
 /*
  * Add context to event or/and channel.
+ * Returns the size of the returned payload data or a negative error code.
  */
 int lttng_add_context(struct lttng_handle *handle,
 		struct lttng_event_context *ctx, const char *event_name,
------------------------------

Daniel U. Thibault
R & D pour la défense Canada - Valcartier (RDDC Valcartier) / Defence R&D Canada - Valcartier (DRDC Valcartier)
Système de systèmes (SdS) / System of Systems (SoS)
Solutions informatiques et expérimentations (SIE) / Computing Solutions and Experimentations (CSE)
2459 Boul. Pie XI Nord
Québec, QC  G3J 1X5
CANADA
Vox : (418) 844-4000 x4245
Fax : (418) 844-4538
NAC: 918V QSDJ
Gouvernement du Canada / Government of Canada
<http://www.valcartier.drdc-rddc.gc.ca/>