core: Introduce chaos into memory allocations

Locate potential crashes by exercising seldom
used code paths.  This patch introduces a new
define DEBUG_CHAOS, and mechanism to randomly
return an error condition from functions that
will seldom do so.  Functions that handle the
allocation of memory get the first treatment.

Review: https://reviewboard.asterisk.org/r/4463/
........

Merged revisions 433060 from http://svn.asterisk.org/svn/asterisk/branches/13

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@433063 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/build_tools/cflags.xml b/build_tools/cflags.xml
index 082e8e63fd8d05a989507c00ab443219273ea984..49a3547672fa22259680539b6e2a520f3fa586fa 100644 (file)
--- a/build_tools/cflags.xml
+++ b/build_tools/cflags.xml
@@ -79,6 +79,10 @@
                <member name="MALLOC_DEBUG" displayname="Keep Track of Memory Allocations">
                        <support_level>core</support_level>
                </member>
+               <member name="DEBUG_CHAOS" displayname="Randomly FAIL memory allocations or other operations">
+                       <conflict>MALLOC_DEBUG</conflict>
+                       <support_level>core</support_level>
+               </member>
                <member name="BUSYDETECT_TONEONLY" displayname="Enable additional comparision of only the tone duration not the silence part">
                        <conflict>BUSYDETECT_COMPARE_TONE_AND_SILENCE</conflict>
                        <defaultenabled>no</defaultenabled>

diff --git a/include/asterisk/utils.h b/include/asterisk/utils.h
index 1dc351d0acbc1e6b626ace3b836458a74bbbe87f..e4c4c8bea17c8f3f8613f36f5efd80e17236b7ac 100644 (file)
--- a/include/asterisk/utils.h
+++ b/include/asterisk/utils.h
@@ -485,6 +485,32 @@ long int ast_random(void);
  */
 #define ast_random_double() (((double)ast_random()) / RAND_MAX)
 
+/*!
+ * \brief DEBUG_CHAOS returns failure randomly
+ *
+ * DEBUG_CHAOS_RETURN(failure); can be used to fake
+ * failure of functions such as memory allocation,
+ * for the purposes of testing failure handling.
+ */
+#ifdef DEBUG_CHAOS
+#ifndef DEBUG_CHAOS_ALLOC_CHANCE
+#define DEBUG_CHAOS_ALLOC_CHANCE 100000
+#endif
+/* Could #define DEBUG_CHAOS_ENABLE ast_fully_booted */
+#ifndef DEBUG_CHAOS_ENABLE
+#define DEBUG_CHAOS_ENABLE 1
+#endif
+#define DEBUG_CHAOS_RETURN(CHANCE, FAILURE) \
+       do { \
+               if ((DEBUG_CHAOS_ENABLE) && (ast_random() % CHANCE == 0)) { \
+                       return FAILURE; \
+               } \
+       } while (0)
+#else
+#define DEBUG_CHAOS_RETURN(c,f)
+#endif
+
+
 #ifndef __AST_DEBUG_MALLOC
 #define ast_std_malloc malloc
 #define ast_std_calloc calloc
@@ -537,6 +563,8 @@ void * attribute_malloc _ast_malloc(size_t len, const char *file, int lineno, co
 {
        void *p;
 
+       DEBUG_CHAOS_RETURN(DEBUG_CHAOS_ALLOC_CHANCE, NULL);
+
        if (!(p = malloc(len))) {
                MALLOC_FAILURE_MSG;
        }
@@ -561,6 +589,8 @@ void * attribute_malloc _ast_calloc(size_t num, size_t len, const char *file, in
 {
        void *p;
 
+       DEBUG_CHAOS_RETURN(DEBUG_CHAOS_ALLOC_CHANCE, NULL);
+
        if (!(p = calloc(num, len))) {
                MALLOC_FAILURE_MSG;
        }
@@ -598,6 +628,8 @@ void * attribute_malloc _ast_realloc(void *p, size_t len, const char *file, int
 {
        void *newp;
 
+       DEBUG_CHAOS_RETURN(DEBUG_CHAOS_ALLOC_CHANCE, NULL);
+
        if (!(newp = realloc(p, len))) {
                MALLOC_FAILURE_MSG;
        }
@@ -626,6 +658,8 @@ char * attribute_malloc _ast_strdup(const char *str, const char *file, int linen
 {
        char *newstr = NULL;
 
+       DEBUG_CHAOS_RETURN(DEBUG_CHAOS_ALLOC_CHANCE, NULL);
+
        if (str) {
                if (!(newstr = strdup(str))) {
                        MALLOC_FAILURE_MSG;
@@ -656,6 +690,8 @@ char * attribute_malloc _ast_strndup(const char *str, size_t len, const char *fi
 {
        char *newstr = NULL;
 
+       DEBUG_CHAOS_RETURN(DEBUG_CHAOS_ALLOC_CHANCE, NULL);
+
        if (str) {
                if (!(newstr = strndup(str, len))) {
                        MALLOC_FAILURE_MSG;
@@ -697,6 +733,8 @@ int _ast_vasprintf(char **ret, const char *file, int lineno, const char *func, c
 {
        int res;
 
+       DEBUG_CHAOS_RETURN(DEBUG_CHAOS_ALLOC_CHANCE, -1);
+
        if ((res = vasprintf(ret, fmt, ap)) == -1) {
                MALLOC_FAILURE_MSG;
        }