buflib: Add crc field protecting buflib cookie integrity

This should catch the case of buffer misuse which results
in corrupted cookie of next allocation. The check is performed
on move_block() so it may be a bit late.

There is buflib_check_valid() provided which checks the
integrity of all cookies for given context.
On DEBUG build with --sdl-thread this check is carried out
for core_ctx on every context switch to catch problems earlier.

Change-Id: I999d4576084592394e3dbd3bdf0f32935ff5f601
Reviewed-on: http://gerrit.rockbox.org/711
Reviewed-by: Thomas Martitz <kugel@rockbox.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/firmware/common/crc32.c b/firmware/common/crc32.c
index 1cd0ca0bd5..c8c70e415c 100644
--- a/firmware/common/crc32.c
+++ b/firmware/common/crc32.c
@@ -25,7 +25,7 @@
 
 /* Tool function to calculate a CRC32 across some buffer */
 /* third argument is either 0xFFFFFFFF to start or value from last piece */
-unsigned crc_32(const void *src, unsigned len, unsigned crc32)
+uint32_t crc_32(const void *src, uint32_t len, uint32_t crc32)
 {
     const unsigned char *buf = (const unsigned char *)src;
     
@@ -39,7 +39,7 @@ unsigned crc_32(const void *src, unsigned len, unsigned crc32)
     };
 
     unsigned char byte;
-    unsigned t;
+    uint32_t t;
 
     while (len--)
     {