From: lace <>
Date: Sun, 1 Jun 2008 08:13:43 +0000 (+0000)
Subject: glibc malloc() mangler.
X-Git-Url: http://git.jankratochvil.net/?p=nethome.git;a=commitdiff_plain;h=6694e46ce2a90eaec122fec1fc755fc2d7493175;hp=2e1506d8e589032e8514ace616eca12574b85753

glibc malloc() mangler.
---

diff --git a/src/glibcmangle.c b/src/glibcmangle.c
new file mode 100644
index 0000000..e1f1c1a
--- /dev/null
+++ b/src/glibcmangle.c
@@ -0,0 +1,109 @@
+/* Prototypes for __malloc_hook, __free_hook, __realloc_hook */
+#include <malloc.h>
+#include <string.h>
+
+/* Prototypes for our hooks.  */
+static void my_init_hook (void);
+static void *my_malloc_hook (size_t, const void *);
+static void my_free_hook (void *, const void *);
+static void *my_realloc_hook (void *, size_t, const void *);
+
+/* Override initializing hook from the C library. */
+void (*__malloc_initialize_hook) (void) = my_init_hook;
+
+static void (*old_free_hook) __MALLOC_PMT ((void *__ptr,
+					__const __malloc_ptr_t));
+static void *(*old_malloc_hook) __MALLOC_PMT ((size_t __size,
+					     __const __malloc_ptr_t));
+static void *(*old_realloc_hook) __MALLOC_PMT ((void *__ptr, size_t __size,
+					      __const __malloc_ptr_t));
+
+static void
+my_init_hook (void)
+{
+  old_malloc_hook = __malloc_hook;
+  old_free_hook = __free_hook;
+  old_realloc_hook = __realloc_hook;
+  __malloc_hook = my_malloc_hook;
+  __free_hook = my_free_hook;
+  __realloc_hook = my_realloc_hook;
+}
+
+static void *
+my_malloc_hook (size_t size, const void *caller)
+{
+  void *result;
+  /* Restore all old hooks */
+  __malloc_hook = old_malloc_hook;
+  __free_hook = old_free_hook;
+  __realloc_hook = old_realloc_hook;
+  /* Call recursively */
+  result = malloc (sizeof (size_t) + size);
+  if (result != NULL)
+    {
+      *(size_t *) result = size;
+      result += sizeof (size_t);
+      memset (result, 0xF3, size);
+    }
+  /* Restore our own hooks */
+  __malloc_hook = my_malloc_hook;
+  __free_hook = my_free_hook;
+  __realloc_hook = my_realloc_hook;
+  return result;
+}
+
+static void
+my_free_hook (void *ptr, const void *caller)
+{
+  /* Restore all old hooks */
+  __malloc_hook = old_malloc_hook;
+  __free_hook = old_free_hook;
+  __realloc_hook = old_realloc_hook;
+  if (ptr != NULL)
+    {
+      ptr -= sizeof (size_t);
+      size_t size = *(size_t *) ptr;
+
+      memset (ptr, 0xD7, sizeof (size_t) + size);
+    }
+  /* Call recursively */
+  free (ptr);
+  /* Restore our own hooks */
+  __malloc_hook = my_malloc_hook;
+  __free_hook = my_free_hook;
+  __realloc_hook = my_realloc_hook;
+}
+
+static void *
+my_realloc_hook (void *ptr, size_t size, const void *caller)
+{
+  void *result;
+  size_t old_size = 0;
+
+  /* Restore all old hooks */
+  __malloc_hook = old_malloc_hook;
+  __free_hook = old_free_hook;
+  __realloc_hook = old_realloc_hook;
+  if (ptr != NULL)
+    {
+      ptr -= sizeof (size_t);
+      old_size = *(size_t *) ptr;
+
+      if (size < old_size)
+        memset (ptr + sizeof (size_t) + size, 0x7D, old_size - size);
+    }
+  /* Call recursively */
+  result = realloc (ptr, (size != 0 ? sizeof (size_t) + size : 0));
+  if (result != NULL)
+    {
+      *(size_t *) result = size;
+      result += sizeof (size_t);
+      if (size > old_size)
+        memset (result + old_size, 0x3F, size - old_size);
+    }
+  /* Restore our own hooks */
+  __malloc_hook = my_malloc_hook;
+  __free_hook = my_free_hook;
+  __realloc_hook = my_realloc_hook;
+  return result;
+}