[PATCH][noMMU] malloc-simple: Make calloc() return zeroed memory

Steven J. Magnani steve at digidescorp.com
Wed Jun 9 14:02:21 UTC 2010


The 0.9.31 release included a change to malloc-simple to request
uninitialized memory from noMMU kernels. Unfortunately, the corresponding
calloc() code assumed that memory returned by malloc() was already zeroed, 
which leads to all kinds of nastiness.

Signed-off-by: Steven J. Magnani <steve at digidescorp.com>
---
diff -uprN a/libc/stdlib/malloc-simple/alloc.c b/libc/stdlib/malloc-simple/alloc.c
--- a/libc/stdlib/malloc-simple/alloc.c	2010-06-09 08:19:33.000000000 -0500
+++ b/libc/stdlib/malloc-simple/alloc.c	2010-06-09 08:40:00.000000000 -0500
@@ -61,14 +61,14 @@ void * calloc(size_t nmemb, size_t lsize
 		return NULL;
 	}
 	result=malloc(size);
-#if 0
-	/* Standard unix mmap using /dev/zero clears memory so calloc
-	 * doesn't need to actually zero anything....
-	 */
+
+#ifndef __ARCH_USE_MMU__
+	/* mmap'd with MAP_UNINITIALIZE, we have to blank memory ourselves */
 	if (result != NULL) {
 		memset(result, 0, size);
 	}
 #endif
+
 	return result;
 }
 #endif



More information about the uClibc mailing list