From: Wolfgang Stöggl <c72578@yahoo.de>
Date: Thu, 11 Jul 2019 13:00:09 +0000 (+0200)
Subject: Use temp pointer for realloc()
X-Git-Tag: v1.8.0~75
X-Git-Url: http://git.ipfire.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=59b1bcbaeab056e774a4ba244e70f8401eecb1ae;p=thirdparty%2Frrdtool-1.x.git

Use temp pointer for realloc()

If realloc() fails, it returns NULL and the original block is
left untouched; it is not freed. Use a temporary pointer first to
check, if realloc() has failed.

- Fixes the following Cppcheck errors:
  [src/rrd_create.c:958] (error) Common realloc mistake: 'mappings'
    nulled but not freed upon failure [memleakOnRealloc]
  [src/rrd_create.c:2451] (error) Common realloc mistake: 'candidates'
    nulled but not freed upon failure [memleakOnRealloc]
  [src/rrd_daemon.c:2402] (error) Common realloc mistake: 'sources'
    nulled but not freed upon failure [memleakOnRealloc]
---

diff --git a/src/rrd_create.c b/src/rrd_create.c
index 6533eb5a..0cb5b78c 100644
--- a/src/rrd_create.c
+++ b/src/rrd_create.c
@@ -955,12 +955,13 @@ int rrd_create_r2(
             parseDS(argv[i] + 3, rrd.ds_def + rrd.stat_head->ds_cnt,
                     &rrd, lookup_DS, &m, &require_version);
 
-            mappings =
+            mapping_t *mappings_tmp =
                 realloc(mappings, sizeof(mapping_t) * (mappings_cnt + 1));
-            if (!mappings) {
+            if (!mappings_tmp) {
                 rrd_set_error("allocating mappings");
                 goto done;
             }
+            mappings = mappings_tmp;
             memcpy(mappings + mappings_cnt, &m, sizeof(mapping_t));
             mappings_cnt++;
 
@@ -2448,14 +2449,16 @@ static candidate_t *find_matching_candidates(
                                (void *) target);
                 }
 
-                candidates = realloc(candidates,
-                                     sizeof(candidate_t) * (cnt +
-                                                            candidate_cnt_for_source));
-                if (candidates == NULL) {
+                candidate_t *candidates_tmp = realloc(candidates,
+                                                      sizeof(candidate_t) *
+                                                      (cnt +
+                                                       candidate_cnt_for_source));
+                if (candidates_tmp == NULL) {
                     rrd_set_error("Cannot realloc memory");
                     free(candidates_for_source);
                     goto done;
                 }
+                candidates = candidates_tmp;
                 memcpy(candidates + cnt,
                        candidates_for_source,
                        sizeof(candidate_t) * candidate_cnt_for_source);
diff --git a/src/rrd_daemon.c b/src/rrd_daemon.c
index 10385799..806f6355 100644
--- a/src/rrd_daemon.c
+++ b/src/rrd_daemon.c
@@ -2399,13 +2399,15 @@ static int handle_request_create(
                 rc = syntax_error(sock, cmd);
                 goto done;
             }
-            sources = realloc(sources, sizeof(char *) * (sources_length + 2));
-            if (sources == NULL) {
+            char    **sources_tmp =
+                realloc(sources, sizeof(char *) * (sources_length + 2));
+            if (sources_tmp == NULL) {
                 rc = send_response(sock, RESP_ERR,
                                    "Cannot allocate memory\n");
                 goto done;
             }
 
+            sources = sources_tmp;
             flush_file(tok);
 
             sources[sources_length++] = tok;