Add magic keyword to detect memory corruption

fdppedu · May 12, 2020 · 05bc01f · 05bc01f
1 parent 47afec6
commit 05bc01f
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Showing 2 changed files with 22 additions and 0 deletions.
diff --git a/ringbuff/src/include/ringbuff/ringbuff.h b/ringbuff/src/include/ringbuff/ringbuff.h
@@ -53,6 +53,12 @@ extern "C" {
  */
 #define RINGBUFF_VOLATILE                       /* volatile */
 
+/**
+ * \brief           Adds 2 magic words to make sure if memory is corrupted
+ *                  application can detect wrong data pointer and maximum size
+ */
+#define RINGBUFF_USE_MAGIC                      1
+
 /**
  * \brief           Event type for buffer operations
  */
@@ -79,12 +85,18 @@ typedef void (*ringbuff_evt_fn)(RINGBUFF_VOLATILE struct ringbuff* buff, ringbuf
  * \brief           Buffer structure
  */
 typedef struct ringbuff {
+#ifdef RINGBUFF_USE_MAGIC
+    uint32_t magic1;                            /*!< Magic 1 word */
+#endif /* RINGBUFF_USE_MAGIC */
     uint8_t* buff;                              /*!< Pointer to buffer data.
                                                     Buffer is considered initialized when `buff != NULL` and `size > 0` */
     size_t size;                                /*!< Size of buffer data. Size of actual buffer is `1` byte less than value holds */
     size_t r;                                   /*!< Next read pointer. Buffer is considered empty when `r == w` and full when `w == r - 1` */
     size_t w;                                   /*!< Next write pointer. Buffer is considered empty when `r == w` and full when `w == r - 1` */
     ringbuff_evt_fn evt_fn;                     /*!< Pointer to event callback function */
+#ifdef RINGBUFF_USE_MAGIC
+    uint32_t magic2;                            /*!< Magic 2 word */
+#endif /* RINGBUFF_USE_MAGIC */
 } ringbuff_t;
 
 uint8_t     ringbuff_init(RINGBUFF_VOLATILE ringbuff_t* buff, void* buffdata, size_t size);

diff --git a/ringbuff/src/ringbuff/ringbuff.c b/ringbuff/src/ringbuff/ringbuff.c
@@ -36,7 +36,12 @@
 /* Memory set and copy functions */
 #define BUF_MEMSET                      memset
 #define BUF_MEMCPY                      memcpy
+
+#ifdef RINGBUFF_USE_MAGIC
+#define BUF_IS_VALID(b)                 ((b) != NULL && (b)->magic1 == 0xDEADBEEF && (b)->magic2 == ~0xDEADBEEF && (b)->buff != NULL && (b)->size > 0)
+#else
 #define BUF_IS_VALID(b)                 ((b) != NULL && (b)->buff != NULL && (b)->size > 0)
+#endif /* RINGBUFF_USE_MAGIC */
 #define BUF_MIN(x, y)                   ((x) < (y) ? (x) : (y))
 #define BUF_MAX(x, y)                   ((x) > (y) ? (x) : (y))
 #define BUF_SEND_EVT(b, type, bp)       do { if ((b)->evt_fn != NULL) { (b)->evt_fn((b), (type), (bp)); } } while (0)
@@ -60,6 +65,11 @@ ringbuff_init(RINGBUFF_VOLATILE ringbuff_t* buff, void* buffdata, size_t size) {
     buff->size = size;
     buff->buff = buffdata;
 
+#ifdef RINGBUFF_USE_MAGIC
+    buff->magic1 = 0xDEADBEEF;
+    buff->magic2 = ~0xDEADBEEF;
+#endif /* RINGBUFF_USE_MAGIC */
+
     return 1;
 }