[lttng-dev] [PATCH] lttng-tools add_context.c : Fixing memory leaks

[Daniel.Thibault@drdc-rddc.gc.ca (Thibault, Daniel)]

> For some reason, this patch does not apply ...

   Okay, my git repository is now properly connected, and below is the patch rewritten for the current commit.  Besides enforcing the return values and outputting --help to stdout, the problem lay with the instances of struct ctx_type *type being created but not assigned to the doubly-linked list under various error conditions.

------------------------------
From e8e3c1db9311fda3b01a9318e263ce55b476222f Mon, 30 Jan 2012 16:55:02 -0500
From: Daniel U. Thibault <daniel.thibault@drdc-rddc.gc.ca>
Date: Mon, 30 Jan 2012 16:54:47 -0500
Subject: [PATCH] lttng-tools add_context : Fixing memory leaks

Signed-off-by: Daniel U. Thibault <daniel.thibault at drdc-rddc.gc.ca>

diff --git a/src/bin/lttng/commands/add_context.c b/src/bin/lttng/commands/add_context.c
index 2f3bce1..2fec520 100644
--- a/src/bin/lttng/commands/add_context.c
+++ b/src/bin/lttng/commands/add_context.c
@@ -313,14 +313,14 @@
 	fprintf(ofp, "Options:\n");
 	fprintf(ofp, "  -h, --help               Show this help\n");
 	fprintf(ofp, "      --list-options       Simple listing of options\n");
-	fprintf(ofp, "  -s, --session NAME       Apply on session name\n");
-	fprintf(ofp, "  -c, --channel NAME       Apply on channel\n");
-	fprintf(ofp, "  -e, --event NAME         Apply on event\n");
+	fprintf(ofp, "  -s, --session NAME       Apply to session name\n");
+	fprintf(ofp, "  -c, --channel NAME       Apply to channel\n");
+	fprintf(ofp, "  -e, --event NAME         Apply to event\n");
 	fprintf(ofp, "  -k, --kernel             Apply to the kernel tracer\n");
 #if 0
 	fprintf(ofp, "  -u, --userspace [CMD]    Apply to the user-space tracer\n");
 	fprintf(ofp, "                           If no CMD, the domain used is UST global\n");
-	fprintf(ofp, "                           or else the domain is UST EXEC_NAME\n");
+	fprintf(ofp, "                           otherwise the domain is UST EXEC_NAME\n");
 	fprintf(ofp, "  -p, --pid PID            If -u, apply to specific PID (domain: UST PID)\n");
 #else
 	fprintf(ofp, "  -u, --userspace          Apply to the user-space tracer\n");
@@ -385,7 +385,7 @@
 		goto error;
 	}
 
-	/* Iterate over all context type given */
+	/* Iterate over all the context types given */
 	cds_list_for_each_entry(type, &ctx_type_list.head, list) {
 		context.ctx = type->opt->ctx_type;
 		if (context.ctx == LTTNG_EVENT_CONTEXT_PERF_COUNTER) {
@@ -444,7 +444,7 @@
 }
 
 /*
- * Add context on channel or event.
+ * Add context to channel or event.
  */
 int cmd_add_context(int argc, const char **argv)
 {
@@ -455,6 +455,7 @@
 
 	if (argc < 2) {
 		usage(stderr);
+		ret = CMD_ERROR;
 		goto end;
 	}
 
@@ -464,17 +465,10 @@
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stderr);
+			usage(stdout);
 			ret = CMD_SUCCESS;
 			goto end;
 		case OPT_TYPE:
-			type = malloc(sizeof(struct ctx_type));
-			if (type == NULL) {
-				perror("malloc ctx_type");
-				ret = -1;
-				goto end;
-			}
-
 			/*
 			 * Look up the index of opt_type in ctx_opts[] first, so we don't
 			 * have to free(type) on failure.
@@ -482,11 +476,21 @@
 			index = find_ctx_type_idx(opt_type);
 			if (index < 0) {
 				ERR("Unknown context type %s", opt_type);
+				ret = CMD_ERROR;
+				goto end;
+			}
+			type = malloc(sizeof(struct ctx_type));
+			if (type == NULL) {
+				perror("malloc ctx_type");
+				ret = CMD_FATAL;
 				goto end;
 			}
 			type->opt = &ctx_opts[index];
 			if (type->opt->ctx_type == -1) {
 				ERR("Unknown context type %s", opt_type);
+				free(type);
+				ret = CMD_ERROR;
+				goto end;
 			} else {
 				cds_list_add(&type->list, &ctx_type_list.head);
 			}
@@ -511,7 +515,7 @@
 	if (!opt_session_name) {
 		session_name = get_session_name();
 		if (session_name == NULL) {
-			ret = -1;
+			ret = CMD_ERROR;
 			goto end;
 		}
 	} else {
@@ -520,11 +524,11 @@
 
 	ret = add_context(session_name);
 
+end:
 	/* Cleanup allocated memory */
 	cds_list_for_each_entry_safe(type, tmptype, &ctx_type_list.head, list) {
 		free(type);
 	}
 
-end:
 	return ret;
 }
------------------------------

Daniel U. Thibault
R & D pour la d?fense Canada - Valcartier (RDDC Valcartier) / Defence R&D Canada - Valcartier (DRDC Valcartier)
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<http://www.valcartier.drdc-rddc.gc.ca/>