Some clean-ups in fence_malloc() and fence_free()

This patch removes an unnecessary typecast of MAP_FAILED,
replaces an erroneous free() by the correct munmap() in the
error path for a failing mprotect(), and, finally, removes
redundant calls to mprotect() that aren't necessary, because
munmap() doesn't call for any specific memory protection.

diff --git a/test/utils.c b/test/utils.c
index 2ed5051..f6278fe 100644 (file)
--- a/test/utils.c
+++ b/test/utils.c
@@ -243,7 +243,7 @@ fence_malloc (uint32_t len)
     addr = mmap (NULL, n_bytes, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS,
                 -1, 0);
 
-    if (addr == (void *)MAP_FAILED)
+    if (addr == MAP_FAILED)
     {
        printf ("mmap failed on %u %u\n", len, n_bytes);
        return NULL;
@@ -259,20 +259,12 @@ fence_malloc (uint32_t len)
     ((info_t *)initial_page)->trailing = trailing_protected;
     ((info_t *)initial_page)->n_bytes = n_bytes;
 
-    if (mprotect (leading_protected, N_LEADING_PROTECTED * page_size,
-                 PROT_NONE) == -1)
+    if ((mprotect (leading_protected, N_LEADING_PROTECTED * page_size,
+                 PROT_NONE) == -1) ||
+       (mprotect (trailing_protected, N_TRAILING_PROTECTED * page_size,
+                 PROT_NONE) == -1))
     {
-       free (addr);
-       return NULL;
-    }
-
-    if (mprotect (trailing_protected, N_TRAILING_PROTECTED * page_size,
-                 PROT_NONE) == -1)
-    {
-       mprotect (leading_protected, N_LEADING_PROTECTED * page_size,
-                 PROT_READ | PROT_WRITE);
-
-       free (addr);
+       munmap (addr, n_bytes);
        return NULL;
     }
 
@@ -287,13 +279,6 @@ fence_free (void *data)
     uint8_t *leading_protected = payload - N_LEADING_PROTECTED * page_size;
     uint8_t *initial_page = leading_protected - page_size;
     info_t *info = (info_t *)initial_page;
-    uint8_t *trailing_protected = info->trailing;
-
-    mprotect (leading_protected, N_LEADING_PROTECTED * page_size,
-             PROT_READ | PROT_WRITE);
-
-    mprotect (trailing_protected, N_LEADING_PROTECTED * page_size,
-             PROT_READ | PROT_WRITE);
 
     munmap (info->addr, info->n_bytes);
 }