xmalloc: Add and use xcalloc

Add a wrapper for calloc which checks for integer overflows in the
calculation of the size to allocate.

Use xcalloc to allocate an array of objects instead of calculating the
size ourselves, which might cause an integer overflow.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

1 files changed, 15 insertions, 0 deletions

diff --git a/xmalloc.c b/xmalloc.c
index 02d6ce4..bdb6234 100644
--- a/xmalloc.c
+++ b/xmalloc.c
@@ -34,6 +34,21 @@ void *xmalloc(size_t size)
 	return ptr;
 }
 
+void *xcalloc(size_t nmemb, size_t size)
+{
+	void *ptr;
+
+	if (unlikely(nmemb == 0 || size == 0))
+		panic("xcalloc: zero size\n");
+
+	ptr = calloc(nmemb, size);
+	if (unlikely(ptr == NULL))
+		panic("xcalloc: out of memory (allocating %zu members of "
+		      "%zu bytes)\n", nmemb, size);
+
+	return ptr;
+}
+
 void *xzmalloc(size_t size)
 {
 	void *ptr = xmalloc(size);