From: David Herrmann <dh.herrmann@gmail.com>
Date: Fri, 13 Jun 2014 16:43:22 +0000 (+0200)
Subject: util: add realloc_multiply() helper
X-Git-Tag: v215~410
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=9489490a693ec5d1e3b49eecedb0ca5511568665;hp=368504f485d09b9fd48b7538e71981f648eb32bb

util: add realloc_multiply() helper

This is similar to malloc_multiply() and friends. It is realloc() with a
multiplication-overflow check.
---

diff --git a/src/shared/util.h b/src/shared/util.h
index 5a2f10387..8ddd1a5da 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -672,6 +672,13 @@ _malloc_  _alloc_(1, 2) static inline void *malloc_multiply(size_t a, size_t b)
         return malloc(a * b);
 }
 
+_alloc_(2, 3) static inline void *realloc_multiply(void *p, size_t a, size_t b) {
+        if (_unlikely_(b != 0 && a > ((size_t) -1) / b))
+                return NULL;
+
+        return realloc(p, a * b);
+}
+
 _alloc_(2, 3) static inline void *memdup_multiply(const void *p, size_t a, size_t b) {
         if (_unlikely_(b != 0 && a > ((size_t) -1) / b))
                 return NULL;