[libvirt] [PATCH] build: avoid non-portable byte-swapping
Commit 0fc89098 used functions only available on glibc, completely
botched 32-bit environments, and risked SIGBUS due to unaligned
memory access on platforms that aren't as forgiving as x86_64.
* bootstrap.conf (gnulib_modules): Import ffsl.
* src/util/bitmap.c (includes): Use <strings.h> for ffsl.
(virBitmapNewData, virBitmapToData): Avoid 64-bit assumptions and
non-portable functions.
---
I wish I could push this under the build-breaker rule, but it is
not quite trivial enough.
bootstrap.conf | 1 +
src/util/bitmap.c | 38 +++++++++++++++++++++++++++-----------
2 files changed, 28 insertions(+), 11 deletions(-)
diff --git a/bootstrap.conf b/bootstrap.conf
index 2847c0b..23000ac 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -44,6 +44,7 @@ fcntl
fcntl-h
fdatasync
ffs
+ffsl
fnmatch
fsync
func
diff --git a/src/util/bitmap.c b/src/util/bitmap.c
index 51e567a..4bade6c 100644
--- a/src/util/bitmap.c
+++ b/src/util/bitmap.c
@@ -1,7 +1,7 @@
/*
* bitmap.h: Simple bitmap operations
*
- * Copyright (C) 2010-2011 Red Hat, Inc.
+ * Copyright (C) 2010-2012 Red Hat, Inc.
* Copyright (C) 2010 Novell, Inc.
*
* This library is free software; you can redistribute it and/or
@@ -27,6 +27,7 @@
#include <stdint.h>
#include <stdio.h>
#include <string.h>
+#include <strings.h>
#include <stdlib.h>
#include <sys/types.h>
@@ -418,15 +419,23 @@ virBitmapPtr virBitmapNewCopy(virBitmapPtr src)
virBitmapPtr virBitmapNewData(void *data, int len)
{
virBitmapPtr bitmap;
- int i;
+ int i, j;
+ unsigned long *p;
+ unsigned char *bytes = data;
bitmap = virBitmapNew(len * CHAR_BIT);
if (!bitmap)
return NULL;
- memcpy(bitmap->map, data, len);
- for (i = 0; i < bitmap->map_len; i++)
- bitmap->map[i] = le64toh(bitmap->map[i]);
+ /* le64toh is not provided by gnulib, so we do the conversion by hand */
+ p = bitmap->map;
+ for (i = j = 0; i < len; i++, j++) {
+ if (j == sizeof(*p)) {
+ j = 0;
+ p++;
+ }
+ *p |= bytes[i] << (j * CHAR_BIT);
+ }
return bitmap;
}
@@ -446,19 +455,26 @@ int virBitmapToData(virBitmapPtr bitmap, unsigned char **data, int
*dataLen)
{
int len;
unsigned long *l;
- int i;
+ int i, j;
+ unsigned char *bytes;
- len = bitmap->map_len * (VIR_BITMAP_BITS_PER_UNIT / CHAR_BIT);
+ len = (bitmap->max_bit + CHAR_BIT - 1) / CHAR_BIT;
if (VIR_ALLOC_N(*data, len) < 0)
return -1;
- memcpy(*data, bitmap->map, len);
+ bytes = *data;
*dataLen = len;
- l = (unsigned long *)*data;
- for (i = 0; i < bitmap->map_len; i++, l++)
- *l = htole64(*l);
+ /* htole64 is not provided by gnulib, so we do the conversion by hand */
+ l = bitmap->map;
+ for (i = j = 0; i < len; i++, j++) {
+ if (j == sizeof(*l)) {
+ j = 0;
+ l++;
+ }
+ bytes[i] = *l >> (j * CHAR_BIT);
+ }
return 0;
}
--
1.7.11.4