Fix: leak of lookup_method_name in uprobe load

Eliminate string copies in uprobe loading code, which fixes
a memory leak of lookup_method_name reported by Coverity.

Reported-by: Coverity Scan (1395215 Resource leak)
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/common/config/session-config.c b/src/common/config/session-config.c
index e207e8b17c2d1e8bd41b4528030fa6dbc7b24652..78d0c8b73357fa91a01fcc3cacbe26a119800da2 100644 (file)
--- a/src/common/config/session-config.c
+++ b/src/common/config/session-config.c
@@ -1479,9 +1479,8 @@ struct lttng_userspace_probe_location *
 process_userspace_probe_function_attribute_node(
                xmlNodePtr attribute_node)
 {
-       xmlChar *content;
        xmlNodePtr function_attribute_node;
-       char *function_name = NULL, *binary_path = NULL, *lookup_method_name;
+       char *function_name = NULL, *binary_path = NULL;
        struct lttng_userspace_probe_location *location = NULL;
        struct lttng_userspace_probe_location_lookup_method *lookup_method = NULL;
 
@@ -1499,42 +1498,23 @@ process_userspace_probe_function_attribute_node(
                /* Handle function name, binary path and lookup method. */
                if (!strcmp((const char *) function_attribute_node->name,
                                        config_element_userspace_probe_function_location_function_name)) {
-                       content = xmlNodeGetContent(function_attribute_node);
-                       if (!content) {
-                               goto error;
-                       }
-
-                       function_name = lttng_strndup((char *) content, LTTNG_SYMBOL_NAME_LEN);
-                       free(content);
+                       function_name = (char *) xmlNodeGetContent(function_attribute_node);
                        if (!function_name) {
-                               PERROR("Error duplicating function name");
                                goto error;
                        }
                } else if (!strcmp((const char *) function_attribute_node->name,
                                        config_element_userspace_probe_location_binary_path)) {
-                       content = xmlNodeGetContent(function_attribute_node);
-                       if (!content) {
-                               goto error;
-                       }
-
-                       binary_path = lttng_strndup((char *) content, LTTNG_PATH_MAX);
-                       free(content);
+                       binary_path = (char *) xmlNodeGetContent(function_attribute_node);
                        if (!binary_path) {
-                               PERROR("Error duplicating binary path");
                                goto error;
                        }
                } else if (!strcmp((const char *) function_attribute_node->name,
                                        config_element_userspace_probe_lookup)) {
-                       content = xmlNodeGetContent(function_attribute_node);
-                       if (!content) {
-                               goto error;
-                       }
+                       char *lookup_method_name;
 
-                       lookup_method_name = lttng_strndup((char *) content,
-                                       CONFIG_USERSPACE_PROBE_LOOKUP_METHOD_NAME_MAX_LEN);
-                       free(content);
+                       lookup_method_name = (char *) xmlNodeGetContent(
+                                       function_attribute_node);
                        if (!lookup_method_name) {
-                               PERROR("Error duplicating lookup method name");
                                goto error;
                        }
 
@@ -1547,12 +1527,13 @@ process_userspace_probe_function_attribute_node(
                                lookup_method = lttng_userspace_probe_location_lookup_method_function_elf_create();
                                if (!lookup_method) {
                                        PERROR("Error creating function default/ELF lookup method");
-                                       free(lookup_method_name);
-                                       goto error;
                                }
                        } else {
-                               WARN("Unknown function lookup method.");
-                               free(lookup_method_name);
+                               WARN("Unknown function lookup method");
+                       }
+
+                       free(lookup_method_name);
+                       if (!lookup_method) {
                                goto error;
                        }
                } else {
@@ -1561,20 +1542,19 @@ process_userspace_probe_function_attribute_node(
 
                /* Check if all the necessary fields were found. */
                if (binary_path && function_name && lookup_method) {
+                       /* Ownership of lookup_method is transferred. */
                        location =
                                lttng_userspace_probe_location_function_create(
                                                binary_path, function_name,
                                                lookup_method);
-                       goto end;
+                       lookup_method = NULL;
+                       goto error;
                }
        }
 error:
+       lttng_userspace_probe_location_lookup_method_destroy(lookup_method);
        free(binary_path);
        free(function_name);
-       if (lookup_method) {
-               lttng_userspace_probe_location_lookup_method_destroy(lookup_method);
-       }
-end:
        return location;
 }
 
@@ -1583,9 +1563,7 @@ struct lttng_userspace_probe_location *
 process_userspace_probe_tracepoint_attribute_node(
                xmlNodePtr attribute_node)
 {
-       xmlChar *content;
        xmlNodePtr tracepoint_attribute_node;
-       char *lookup_method_name = NULL;
        char *probe_name = NULL, *provider_name = NULL, *binary_path = NULL;
        struct lttng_userspace_probe_location *location = NULL;
        struct lttng_userspace_probe_location_lookup_method *lookup_method = NULL;
@@ -1602,58 +1580,29 @@ process_userspace_probe_tracepoint_attribute_node(
                                tracepoint_attribute_node)) {
                if (!strcmp((const char *) tracepoint_attribute_node->name,
                                        config_element_userspace_probe_tracepoint_location_probe_name)) {
-                       content = xmlNodeGetContent(tracepoint_attribute_node);
-                       if (!content) {
-                               goto error;
-                       }
-
-                       probe_name = lttng_strndup((char*) content, LTTNG_SYMBOL_NAME_LEN);
-                       free(content);
+                       probe_name = (char *) xmlNodeGetContent(tracepoint_attribute_node);
                        if (!probe_name) {
-                               PERROR("Error duplicating probe name");
                                goto error;
                        }
                } else if (!strcmp((const char *) tracepoint_attribute_node->name,
                                        config_element_userspace_probe_tracepoint_location_provider_name)) {
-                       content = xmlNodeGetContent(tracepoint_attribute_node);
-                       if (!content) {
-                               goto error;
-                       }
-
-                       provider_name = lttng_strndup((char*) content, LTTNG_SYMBOL_NAME_LEN);
-                       free(content);
+                       provider_name = (char *) xmlNodeGetContent(tracepoint_attribute_node);
                        if (!provider_name) {
-                               PERROR("Error duplicating provider name");
                                goto error;
                        }
                } else if (!strcmp((const char *) tracepoint_attribute_node->name,
                                        config_element_userspace_probe_location_binary_path)) {
-                       content = xmlNodeGetContent(tracepoint_attribute_node);
-                       if (!content) {
-                               goto error;
-                       }
-
-                       binary_path = lttng_strndup((char*) content, LTTNG_PATH_MAX);
-
-                       free(content);
-
+                       binary_path = (char *) xmlNodeGetContent(tracepoint_attribute_node);
                        if (!binary_path) {
-                               PERROR("Error duplicating binary path");
                                goto error;
                        }
                } else if (!strcmp((const char *) tracepoint_attribute_node->name,
                                        config_element_userspace_probe_lookup)) {
-                       content = xmlNodeGetContent(tracepoint_attribute_node);
-                       if (!content) {
-                               goto error;
-                       }
-
-                       lookup_method_name = lttng_strndup((char *) content,
-                                       CONFIG_USERSPACE_PROBE_LOOKUP_METHOD_NAME_MAX_LEN);
-                       free(content);
+                       char *lookup_method_name;
 
+                       lookup_method_name = (char *) xmlNodeGetContent(
+                                       tracepoint_attribute_node);
                        if (!lookup_method_name) {
-                               PERROR("Error duplicating lookup method name");
                                goto error;
                        }
 
@@ -1663,35 +1612,35 @@ process_userspace_probe_tracepoint_attribute_node(
                                        lttng_userspace_probe_location_lookup_method_tracepoint_sdt_create();
                                if (!lookup_method) {
                                        PERROR("Error creating tracepoint SDT lookup method");
-                                       free(lookup_method_name);
-                                       goto error;
                                }
                        } else {
-                               WARN("Unknown tracepoint lookup method.");
+                               WARN("Unknown tracepoint lookup method");
+                       }
+
+                       free(lookup_method_name);
+                       if (!lookup_method) {
                                goto error;
                        }
                } else {
-                       WARN("Unknown tracepoint attribute.");
+                       WARN("Unknown tracepoint attribute");
                        goto error;
                }
 
                /* Check if all the necessary fields were found. */
                if (binary_path && provider_name && probe_name && lookup_method) {
+                       /* Ownership of lookup_method is transferred. */
                        location =
                                lttng_userspace_probe_location_tracepoint_create(
                                                binary_path, provider_name,
                                                probe_name, lookup_method);
-                       goto end;
+                       goto error;
                }
        }
 error:
+       lttng_userspace_probe_location_lookup_method_destroy(lookup_method);
        free(binary_path);
-       free(probe_name);
        free(provider_name);
-       if (lookup_method) {
-               lttng_userspace_probe_location_lookup_method_destroy(lookup_method);
-       }
-end:
+       free(probe_name);
        return location;
 }