DEBUG: Catch if we write past t_buffer_get()ed memory.

--HG--
branch : HEAD

diff --git a/src/lib/data-stack.c b/src/lib/data-stack.c
index 5df52ef1c3f55e8a3a28b3362f6b23ddbde8356b..35a17bd4211673bebdab345940c90cdcb2b39bf0 100644 (file)
--- a/src/lib/data-stack.c
+++ b/src/lib/data-stack.c
@@ -72,6 +72,33 @@ union {
        unsigned char data[128];
 } outofmem_area;
 
+static void data_stack_last_buffer_reset(void)
+{
+       if (last_buffer_block != NULL) {
+#ifdef DEBUG
+               const unsigned char *p;
+               unsigned int i;
+
+               p = STACK_BLOCK_DATA(current_block) +
+                       (current_block->size - current_block->left) +
+                       MEM_ALIGN(sizeof(size_t) + last_buffer_size);
+#endif
+               /* reset t_buffer_get() mark - not really needed but makes it
+                  easier to notice if t_malloc()/t_push()/t_pop() is called
+                  between t_buffer_get() and t_buffer_alloc().
+                  do this before we get to i_panic() to avoid recursive
+                  panics. */
+               last_buffer_block = NULL;
+
+#ifdef DEBUG
+               for (i = 0; i < SENTRY_COUNT; i++) {
+                       if (p[i] != CLEAR_CHR)
+                               i_panic("t_buffer_get(): buffer overflow");
+               }
+#endif
+       }
+}
+
 unsigned int t_push(void)
 {
         struct stack_frame_block *frame_block;
@@ -107,6 +134,7 @@ unsigned int t_push(void)
                frame_block->prev = current_frame_block;
                current_frame_block = frame_block;
        }
+       data_stack_last_buffer_reset();
 
        /* mark our current position */
        current_frame_block->block[frame_pos] = current_block;
@@ -194,6 +222,7 @@ unsigned int t_pop(void)
 #ifdef DEBUG
        t_pop_verify();
 #endif
+       data_stack_last_buffer_reset();
 
        /* update the current block */
        current_block = current_frame_block->block[frame_pos];
@@ -290,10 +319,7 @@ static void *t_malloc_real(size_t size, bool permanent)
                data_stack_init();
        }
 
-       /* reset t_buffer_get() mark - not really needed but makes it easier
-          to notice if t_malloc() is called between t_buffer_get() and
-          t_buffer_alloc() */
-        last_buffer_block = NULL;
+       data_stack_last_buffer_reset();
 
        /* allocate only aligned amount of memory so alignment comes
           always properly */