Genesis

1 files changed, 29 insertions, 0 deletions

diff --git a/lib/alloc/bufalloc.c b/lib/alloc/bufalloc.c
new file mode 100644
index 0000000..a81f5b9
--- /dev/null
+++ b/lib/alloc/bufalloc.c
@@ -0,0 +1,29 @@
+#include <errno.h>
+#if __has_include(<stdckdint.h>)
+#	include <stdckdint.h>
+#	warning "stdckdint.h now available; remove manual ckd_*() implementations"
+#elifdef __GNUC__
+#	define ckd_add(r, a, b) ((bool)__builtin_add_overflow(a, b, r))
+#	define ckd_mul(r, a, b) ((bool)__builtin_mul_overflow(a, b, r))
+#else
+#	define ckd_add(r, a, b) (*(r) = (a) + (b))
+#	define ckd_mul(r, a, b) (*(r) = (a) * (b))
+#	warning "ckd_*() not supported on the current platform"
+#endif
+#include <stdlib.h>
+
+#include "alloc.h"
+#include "errors.h"
+
+void *
+bufalloc(void *p, size_t n, size_t m)
+{
+	if (ckd_mul(&n, n, m)) {
+		errno = EOVERFLOW;
+		err(__func__);
+	}
+
+	if (!(p = realloc(p, n)))
+		err(__func__);
+	return p;
+}