Fixing memory leaks in add-context command

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.

Signed-off-by: Daniel U. Thibault <daniel.thibault@drdc-rddc.gc.ca>
Signed-off-by: David Goulet <dgoulet@efficios.com>

diff --git a/src/bin/lttng/commands/add_context.c b/src/bin/lttng/commands/add_context.c
index 2f3bce1f5bed2ccffc872a699f1cd8b8ac486e10..ce65024f5f6b912cbf2406d8be8e82018c2b9e90 100644 (file)
--- a/src/bin/lttng/commands/add_context.c
+++ b/src/bin/lttng/commands/add_context.c
@@ -313,14 +313,14 @@ static void usage(FILE *ofp)
        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 @@ static int add_context(char *session_name)
                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 @@ error:
 }
 
 /*
- * 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 @@ int cmd_add_context(int argc, const char **argv)
 
        if (argc < 2) {
                usage(stderr);
+               ret = CMD_ERROR;
                goto end;
        }
 
@@ -464,17 +465,10 @@ int cmd_add_context(int argc, const char **argv)
        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 +476,23 @@ int cmd_add_context(int argc, const char **argv)
                        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 +517,7 @@ int cmd_add_context(int argc, const char **argv)
        if (!opt_session_name) {
                session_name = get_session_name();
                if (session_name == NULL) {
-                       ret = -1;
+                       ret = CMD_ERROR;
                        goto end;
                }
        } else {
@@ -520,11 +526,11 @@ int cmd_add_context(int argc, const char **argv)
 
        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;
 }