allow out-of-memory testing by setting a limit. That number of memory

allocation calls will succeed, the following will return NULL!

lib/memdebug.c

@@ -62,7 +62,10 @@ struct memdebug {
  * Don't use these with multithreaded test programs!
  */
 
-FILE *logfile;
+#define logfile curl_debuglogfile
+FILE *curl_debuglogfile;
+static bool memlimit; /* enable memory limit */
+static long memsize;  /* set number of mallocs allowed */
 
 /* this sets the log file name */
 void curl_memdebug(const char *logname)
@@ -73,12 +76,47 @@ void curl_memdebug(const char *logname)
     logfile = stderr;
 }
 
+/* This function sets the number of malloc() calls that should return
+   successfully! */
+void curl_memlimit(long limit)
+{
+  memlimit = TRUE;
+  memsize = limit;
+}
+
+/* returns TRUE if this isn't allowed! */
+static bool countcheck(const char *func, int line, const char *source)
+{
+  /* if source is NULL, then the call is made internally and this check
+     should not be made */
+  if(memlimit && source) {
+    if(!memsize) {
+      if(logfile && source)
+        fprintf(logfile, "LIMIT %s:%d %s reached memlimit\n",
+                source, line, func);
+      return TRUE; /* RETURN ERROR! */
+    }
+    else
+      memsize--; /* countdown */
+    
+    /* log the countdown */
+    if(logfile && source)
+      fprintf(logfile, "LIMIT %s:%d %ld ALLOCS left\n",
+              source, line, memsize);
+    
+  }
+
+  return FALSE; /* allow this */
+}
 
 void *curl_domalloc(size_t wantedsize, int line, const char *source)
 {
   struct memdebug *mem;
   size_t size;
 
+  if(countcheck("malloc", line, source))
+    return NULL;
+
   /* alloc at least 64 bytes */
   size = sizeof(struct memdebug)+wantedsize;
 
@@ -106,6 +144,9 @@ char *curl_dostrdup(const char *str, int line, const char *source)
     exit(2);
   }
 
+  if(countcheck("strdup", line, source))
+    return NULL;
+
   len=strlen(str)+1;
 
   mem=curl_domalloc(len, 0, NULL); /* NULL prevents logging */
@@ -125,6 +166,9 @@ void *curl_dorealloc(void *ptr, size_t wantedsize,
 
   size_t size = sizeof(struct memdebug)+wantedsize;
 
+  if(countcheck("realloc", line, source))
+    return NULL;
+
   mem = (struct memdebug *)((char *)ptr - offsetof(struct memdebug, mem));
 
   mem=(struct memdebug *)(realloc)(mem, size);

lib/memdebug.h

@@ -39,6 +39,8 @@
 #include <memory.h>
 #endif
 
+#define logfile curl_debuglogfile
+
 extern FILE *logfile;
 
 /* memory functions */
@@ -47,6 +49,7 @@ void *curl_dorealloc(void *ptr, size_t size, int line, const char *source);
 void curl_dofree(void *ptr, int line, const char *source);
 char *curl_dostrdup(const char *str, int line, const char *source);
 void curl_memdebug(const char *logname);
+void curl_memlimit(long limit);
 
 /* file descriptor manipulators */
 int curl_socket(int domain, int type, int protocol, int, const char *);