mem: add memtaint().

[ccan] / ccan / mem / mem.h

diff --git a/ccan/mem/mem.h b/ccan/mem/mem.h
index 68a4aa3c18885c207a9fd11828bc5174bead6905..f2c3d5c7a6f795e2e091df8a545992c6533b50ec 100644 (file)
--- a/ccan/mem/mem.h
+++ b/ccan/mem/mem.h
@@ -149,6 +149,19 @@ static inline bool memeqstr(const void *data, size_t length, const char *string)
        return memeq(data, length, string, strlen(string));
 }
 
+/**
+ * memeqzero - Is a byte array all zeroes?
+ * @data: byte array
+ * @length: length of @data in bytes
+ *
+ * Example:
+ *     if (memeqzero(somebytes, bytes_len)) {
+ *             printf("somebytes == 0!\n");
+ *     }
+ */
+PURE_FUNCTION
+bool memeqzero(const void *data, size_t length);
+
 /**
  * memstarts_str - Does this byte array start with a string prefix?
  * @a: byte array
@@ -262,4 +275,20 @@ static inline void *memcheck_(const void *data, size_t len)
 #else
 #define memcheck(data, len) memcheck_((data), (len))
 #endif
+
+/**
+ * memtaint - mark a memory region unused
+ * @data: start of region
+ * @len: length in bytes
+ *
+ * This writes an "0xdeadbeef" eyecatcher repeatedly to the memory.
+ * When running under valgrind, it also tells valgrind that the memory is
+ * uninitialized, triggering valgrind errors if it is used for branches
+ * or written out (or passed to memcheck!) in future.
+ *
+ * Example:
+ *     // We'll reuse this buffer later, but be sure we don't access it.
+ *     memtaint(somebytes, bytes_len);
+ */
+void memtaint(void *data, size_t len);
 #endif /* CCAN_MEM_H */