Safe memory allocation in cli_handlers

Valgrind pointed out that the memory returned from realloc() is
not initialized. So do that explicitely.

Signed-off-by: Hannes Reinecke <hare@suse.de>

diff --git a/multipathd/cli_handlers.c b/multipathd/cli_handlers.c
index 8367a70..d56a990 100644 (file)
--- a/multipathd/cli_handlers.c
+++ b/multipathd/cli_handlers.c
@@ -19,6 +19,17 @@
 #include "main.h"
 #include "cli.h"
 
+#define REALLOC_REPLY(r, a, m)                                 \
+       do {                                                    \
+               if ((a)) {                                      \
+                       (r) = REALLOC((r), (m) * 2);            \
+                       if ((r)) {                              \
+                               memset((r) + (m), 0, (m));      \
+                               (m) *= 2;                       \
+                       }                                       \
+               }                                               \
+       } while (0)
+
 int
 show_paths (char ** r, int * len, struct vectors * vecs, char * style)
 {
@@ -48,9 +59,7 @@ show_paths (char ** r, int * len, struct vectors * vecs, char * style)
 
                again = ((c - reply) == (maxlen - 1));
 
-               if (again)
-                       reply = REALLOC(reply, maxlen *= 2);
-
+               REALLOC_REPLY(reply, again, maxlen);
        }
        *r = reply;
        *len = (int)(c - reply + 1);
@@ -76,9 +85,7 @@ show_map_topology (char ** r, int * len, struct multipath * mpp)
                c += snprint_multipath_topology(c, reply + maxlen - c, mpp, 2);
                again = ((c - reply) == (maxlen - 1));
 
-               if (again)
-                       reply = REALLOC(reply, maxlen *= 2);
-
+               REALLOC_REPLY(reply, again, maxlen);
        }
        *r = reply;
        *len = (int)(c - reply + 1);
@@ -110,9 +117,7 @@ show_maps_topology (char ** r, int * len, struct vectors * vecs)
 
                again = ((c - reply) == (maxlen - 1));
 
-               if (again)
-                       reply = REALLOC(reply, maxlen *= 2);
-
+               REALLOC_REPLY(reply, again, maxlen);
        }
        *r = reply;
        *len = (int)(c - reply + 1);
@@ -136,31 +141,46 @@ show_config (char ** r, int * len)
                c += snprint_defaults(c, reply + maxlen - c);
                again = ((c - reply) == maxlen);
                if (again) {
-                       reply = REALLOC(reply, maxlen *= 2);
+                       reply = REALLOC(reply, maxlen * 2);
+                       if (!reply)
+                               return 1;
+                       memset(reply + maxlen, 0, maxlen);
+                       maxlen *= 2;
                        continue;
                }
                c += snprint_blacklist(c, reply + maxlen - c);
                again = ((c - reply) == maxlen);
                if (again) {
-                       reply = REALLOC(reply, maxlen *= 2);
+                       reply = REALLOC(reply, maxlen * 2);
+                       if (!reply)
+                               return 1;
+                       memset(reply + maxlen, 0, maxlen);
+                       maxlen *= 2;
                        continue;
                }
                c += snprint_blacklist_except(c, reply + maxlen - c);
                again = ((c - reply) == maxlen);
                if (again) {
-                       reply = REALLOC(reply, maxlen *= 2);
+                       reply = REALLOC(reply, maxlen * 2);
+                       if (!reply)
+                               return 1;
+                       memset(reply + maxlen, 0, maxlen);
+                       maxlen *= 2;
                        continue;
                }
                c += snprint_hwtable(c, reply + maxlen - c, conf->hwtable);
                again = ((c - reply) == maxlen);
                if (again) {
-                       reply = REALLOC(reply, maxlen *= 2);
+                       reply = REALLOC(reply, maxlen * 2);
+                       if (!reply)
+                               return 1;
+                       memset(reply + maxlen, 0, maxlen);
+                       maxlen *= 2;
                        continue;
                }
                c += snprint_mptable(c, reply + maxlen - c, conf->mptable);
                again = ((c - reply) == maxlen);
-               if (again)
-                       reply = REALLOC(reply, maxlen *= 2);
+               REALLOC_REPLY(reply, again, maxlen);
        }
        *r = reply;
        *len = (int)(c - reply + 1);
@@ -289,8 +309,7 @@ show_maps (char ** r, int *len, struct vectors * vecs, char * style)
 
                again = ((c - reply) == (maxlen - 1));
 
-               if (again)
-                       reply = REALLOC(reply, maxlen *= 2);
+               REALLOC_REPLY(reply, again, maxlen);
        }
        *r = reply;
        *len = (int)(c - reply + 1);
@@ -726,19 +745,16 @@ show_blacklist (char ** r, int * len)
        unsigned int maxlen = INITIAL_REPLY_LEN;
        int again = 1;
 
+       reply = MALLOC(maxlen);
+
        while (again) {
-               reply = MALLOC(maxlen);
                if (!reply)
                        return 1;
 
                c = reply;
                c += snprint_blacklist_report(c, maxlen);
                again = ((c - reply) == maxlen);
-               if (again) {
-                       maxlen  *= 2;
-                       FREE(reply);
-                       continue;
-               }
+               REALLOC_REPLY(reply, again, maxlen);
        }
 
        *r = reply;
@@ -763,19 +779,16 @@ show_devices (char ** r, int * len, struct vectors *vecs)
        unsigned int maxlen = INITIAL_REPLY_LEN;
        int again = 1;
 
+       reply = MALLOC(maxlen);
+
        while (again) {
-               reply = MALLOC(maxlen);
                if (!reply)
                        return 1;
 
                c = reply;
                c += snprint_devices(c, maxlen, vecs);
                again = ((c - reply) == maxlen);
-               if (again) {
-                       maxlen  *= 2;
-                       FREE(reply);
-                       continue;
-               }
+               REALLOC_REPLY(reply, again, maxlen);
        }
 
        *r = reply;