From: Jan Engelhardt <jengelh@inai.de>
Date: Wed, 20 Mar 2013 14:23:32 +0000 (+0100)
Subject: libudev: avoid potential misaligned accesses
X-Git-Tag: v199~143
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=acd42fae59096d84e78f1c17bfcc0d8f96486341;ds=sidebyside

libudev: avoid potential misaligned accesses

clang reports:
  src/libudev/libudev-util.c:665:35: warning: cast from
  "const unsigned char *" to "unsigned int *" increases required alignment
  from 1 to 4 [-Wcast-align]
---

diff --git a/src/libudev/libudev-util.c b/src/libudev/libudev-util.c
index 62b7e56c0..44f6e4a86 100644
--- a/src/libudev/libudev-util.c
+++ b/src/libudev/libudev-util.c
@@ -568,7 +568,7 @@ err:
  * Murmurhash is under the MIT license.
  *
  */
-static unsigned int murmur_hash2(const char *key, int len, unsigned int seed)
+static unsigned int murmur_hash2(const char *key, size_t len, unsigned int seed)
 {
         /*
          *  'm' and 'r' are mixing constants generated offline.
@@ -583,17 +583,18 @@ static unsigned int murmur_hash2(const char *key, int len, unsigned int seed)
         /* mix 4 bytes at a time into the hash */
         const unsigned char * data = (const unsigned char *)key;
 
-        while(len >= 4) {
-                unsigned int k = *(unsigned int *)data;
+        while(len >= sizeof(unsigned int)) {
+                unsigned int k;
 
+                memcpy(&k, data, sizeof(k));
                 k *= m;
                 k ^= k >> r;
                 k *= m;
                 h *= m;
                 h ^= k;
 
-                data += 4;
-                len -= 4;
+                data += sizeof(k);
+                len -= sizeof(k);
         }
 
         /* handle the last few bytes of the input array */