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[libvirt] [PATCH] portability: don't include <endian.h>



john levon sun com wrote:
...
> diff --git a/configure.in b/configure.in
> --- a/configure.in
> +++ b/configure.in
> @@ -75,7 +75,7 @@ AC_CHECK_FUNCS([cfmakeraw regexec uname
>  AC_CHECK_FUNCS([cfmakeraw regexec uname sched_getaffinity getuid getgid])
>
>  dnl Availability of various common headers (non-fatal if missing).
> -AC_CHECK_HEADERS([pwd.h paths.h regex.h sys/syslimits.h sys/utsname.h sys/wait.h winsock2.h sched.h termios.h sys/poll.h])
> +AC_CHECK_HEADERS([pwd.h paths.h regex.h sys/syslimits.h sys/utsname.h sys/wait.h winsock2.h sched.h termios.h sys/poll.h endian.h])
>
>  dnl Where are the XDR functions?
>  dnl If portablexdr is installed, prefer that.
> diff --git a/src/storage_backend_fs.c b/src/storage_backend_fs.c
> --- a/src/storage_backend_fs.c
> +++ b/src/storage_backend_fs.c
> @@ -31,10 +31,14 @@
>  #include <errno.h>
>  #include <fcntl.h>
>  #include <unistd.h>
> +#include <string.h>
> +
> +#ifdef HAVE_ENDIAN_H
>  #include <endian.h>
> -#include <byteswap.h>
> -#include <mntent.h>
> -#include <string.h>
> +#else
> +#define __LITTLE_ENDIAN 1234
> +#define __BIG_ENDIAN 4321
> +#endif
>
>  #include <libxml/parser.h>
>  #include <libxml/tree.h>
> @@ -240,6 +244,9 @@ static int virStorageBackendProbeFile(vi
>  }
>
>  #if WITH_STORAGE_FS
> +
> +#include <mntent.h>

Adding the inclusions of <string.h> and <mntent.h> look fine,
but rather than testing for endian.h, it seems we can do away with
it altogether.  Even the __LITTLE_ENDIAN and __BIG_ENDIAN
constants aren't really required.  Rather, all you need is
an indication (dare I say boolean?) of whether a fileTypeInfo
entry is big- or little-endian.  However, even though the
current code treats this field as effectively boolean
(testing a single value and then "else" for the rest),
we can leave it as a wider enum.

I propose this:

>From 65074e8d636a2eae10ceacf2619a6be77f45ee2a Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering redhat com>
Date: Wed, 17 Dec 2008 13:54:04 +0100
Subject: [PATCH] portability: don't include <endian.h>

* src/storage_backend_fs.c: Don't include <endian.h>: not needed.
(LV_BIG_ENDIAN, LV_LITTLE_ENDIAN): Define.
Use those instead of __BIG_ENDIAN and __LITTLE_ENDIAN.
---
 src/storage_backend_fs.c |   29 ++++++++++++++++-------------
 1 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/src/storage_backend_fs.c b/src/storage_backend_fs.c
index 91131e5..8bc77fc 100644
--- a/src/storage_backend_fs.c
+++ b/src/storage_backend_fs.c
@@ -31,7 +31,6 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
-#include <endian.h>
 #include <byteswap.h>
 #include <mntent.h>
 #include <string.h>
@@ -47,6 +46,10 @@
 #include "memory.h"
 #include "xml.h"

+enum lv_endian {
+    LV_LITTLE_ENDIAN = 1, /* 1234 */
+    LV_BIG_ENDIAN         /* 4321 */
+};

 /* Either 'magic' or 'extension' *must* be provided */
 struct FileTypeInfo {
@@ -54,7 +57,7 @@ struct FileTypeInfo {
     const char *magic;  /* Optional string of file magic
                          * to check at head of file */
     const char *extension; /* Optional file extension to check */
-    int endian;           /* Endianness of file format */
+    enum lv_endian endian; /* Endianness of file format */
     int versionOffset;    /* Byte offset from start of file
                            * where we find version number,
                            * -1 to skip version test */
@@ -69,16 +72,16 @@ const struct FileTypeInfo const fileTypeInfo[] = {
     /* Bochs */
     /* XXX Untested
     { VIR_STORAGE_VOL_BOCHS, "Bochs Virtual HD Image", NULL,
-      __LITTLE_ENDIAN, 64, 0x20000,
+      LV_LITTLE_ENDIAN, 64, 0x20000,
       32+16+16+4+4+4+4+4, 8, 1 },*/
     /* CLoop */
     /* XXX Untested
     { VIR_STORAGE_VOL_CLOOP, "#!/bin/sh\n#V2.0 Format\nmodprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n", NULL,
-      __LITTLE_ENDIAN, -1, 0,
+      LV_LITTLE_ENDIAN, -1, 0,
       -1, 0, 0 }, */
     /* Cow */
     { VIR_STORAGE_VOL_FILE_COW, "OOOM", NULL,
-      __BIG_ENDIAN, 4, 2,
+      LV_BIG_ENDIAN, 4, 2,
       4+4+1024+4, 8, 1 },
     /* DMG */
     /* XXX QEMU says there's no magic for dmg, but we should check... */
@@ -92,31 +95,31 @@ const struct FileTypeInfo const fileTypeInfo[] = {
     /* Parallels */
     /* XXX Untested
     { VIR_STORAGE_VOL_FILE_PARALLELS, "WithoutFreeSpace", NULL,
-      __LITTLE_ENDIAN, 16, 2,
+      LV_LITTLE_ENDIAN, 16, 2,
       16+4+4+4+4, 4, 512 },
     */
     /* QCow */
     { VIR_STORAGE_VOL_FILE_QCOW, "QFI", NULL,
-      __BIG_ENDIAN, 4, 1,
+      LV_BIG_ENDIAN, 4, 1,
       4+4+8+4+4, 8, 1 },
     /* QCow 2 */
     { VIR_STORAGE_VOL_FILE_QCOW2, "QFI", NULL,
-      __BIG_ENDIAN, 4, 2,
+      LV_BIG_ENDIAN, 4, 2,
       4+4+8+4+4, 8, 1 },
     /* VMDK 3 */
     /* XXX Untested
     { VIR_STORAGE_VOL_FILE_VMDK, "COWD", NULL,
-      __LITTLE_ENDIAN, 4, 1,
+      LV_LITTLE_ENDIAN, 4, 1,
       4+4+4, 4, 512 },
     */
     /* VMDK 4 */
     { VIR_STORAGE_VOL_FILE_VMDK, "KDMV", NULL,
-      __LITTLE_ENDIAN, 4, 1,
+      LV_LITTLE_ENDIAN, 4, 1,
       4+4+4, 8, 512 },
     /* Connectix / VirtualPC */
     /* XXX Untested
     { VIR_STORAGE_VOL_FILE_VPC, "conectix", NULL,
-      __BIG_ENDIAN, -1, 0,
+      LV_BIG_ENDIAN, -1, 0,
       -1, 0, 0},
     */
 };
@@ -173,7 +176,7 @@ static int virStorageBackendProbeFile(virConnectPtr conn,
         if (fileTypeInfo[i].versionNumber != -1) {
             int version;

-            if (fileTypeInfo[i].endian == __LITTLE_ENDIAN) {
+            if (fileTypeInfo[i].endian == LV_LITTLE_ENDIAN) {
                 version = (head[fileTypeInfo[i].versionOffset+3] << 24) |
                     (head[fileTypeInfo[i].versionOffset+2] << 16) |
                     (head[fileTypeInfo[i].versionOffset+1] << 8) |
@@ -190,7 +193,7 @@ static int virStorageBackendProbeFile(virConnectPtr conn,

         /* Optionally extract capacity from file */
         if (fileTypeInfo[i].sizeOffset != -1) {
-            if (fileTypeInfo[i].endian == __LITTLE_ENDIAN) {
+            if (fileTypeInfo[i].endian == LV_LITTLE_ENDIAN) {
                 def->capacity =
                     ((unsigned long long)head[fileTypeInfo[i].sizeOffset+7] << 56) |
                     ((unsigned long long)head[fileTypeInfo[i].sizeOffset+6] << 48) |
--
1.6.1.rc2.316.geb2f0


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