mirror_zfs/config/user-libblkid.m4
Richard Yao 1db7b9be75 Fix libblkid support
libblkid support is dormant because the autotools check is broken and
liblkid identifies ZFS vdevs as "zfs_member", not "zfs". We fix that
with a few changes:

First, we fix the libblkid autotools check to do a few things:

1. Make a 64MB file, which is the minimum size ZFS permits.
2. Make 4 fake uberblock entries to make libblkid's check succeed.
3. Return 0 upon success to make autotools use the success case.
4. Include stdlib.h to avoid implicit declration of free().
5. Check for "zfs_member", not "zfs"
6. Make --with-blkid disable autotools check (avoids Gentoo sandbox violation)
7. Pass '-lblkid' correctly using LIBS not LDFLAGS.

Second, we change the libblkid support to scan for "zfs_member", not
"zfs".

This makes --with-blkid work on Gentoo.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1751
2013-10-10 16:56:51 -07:00

114 lines
2.9 KiB
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dnl #
dnl # Check for ZFS support in libblkid. This test needs to check
dnl # more than if the library exists because we expect there are
dnl # at least 3 flavors of the library out in the wild:
dnl #
dnl # 1) blkid which has no ZFS support
dnl # 2) blkid with ZFS support and a flawed method of probing
dnl # 3) blkid with ZFS support and a working method of probing
dnl #
dnl # To handle this the check first validates that there is a version
dnl # of the library installed. If there is it creates a simulated
dnl # ZFS filesystem and then links a small test app which attempts
dnl # to detect the simualated filesystem type. If it correctly
dnl # identifies the filesystem as ZFS we can safely assume case 3).
dnl # Otherwise we disable blkid support and resort to manual probing.
dnl #
AC_DEFUN([ZFS_AC_CONFIG_USER_LIBBLKID], [
AC_ARG_WITH([blkid],
[AS_HELP_STRING([--with-blkid],
[support blkid caching @<:@default=check@:>@])],
[],
[with_blkid=check])
LIBBLKID=
AS_IF([test "x$with_blkid" = xyes],
[
AC_SUBST([LIBBLKID], ["-lblkid"])
AC_DEFINE([HAVE_LIBBLKID], 1,
[Define if you have libblkid])
])
AS_IF([test "x$with_blkid" = xcheck],
[
AC_CHECK_LIB([blkid], [blkid_get_cache],
[
AC_MSG_CHECKING([for blkid zfs support])
ZFS_DEV=`mktemp`
truncate -s 64M $ZFS_DEV
echo -en "\x0c\xb1\xba\0\0\0\0\0" | \
dd of=$ZFS_DEV bs=1k count=8 \
seek=128 conv=notrunc &>/dev/null \
>/dev/null 2>/dev/null
echo -en "\x0c\xb1\xba\0\0\0\0\0" | \
dd of=$ZFS_DEV bs=1k count=8 \
seek=132 conv=notrunc &>/dev/null \
>/dev/null 2>/dev/null
echo -en "\x0c\xb1\xba\0\0\0\0\0" | \
dd of=$ZFS_DEV bs=1k count=8 \
seek=136 conv=notrunc &>/dev/null \
>/dev/null 2>/dev/null
echo -en "\x0c\xb1\xba\0\0\0\0\0" | \
dd of=$ZFS_DEV bs=1k count=8 \
seek=140 conv=notrunc &>/dev/null \
>/dev/null 2>/dev/null
saved_LIBS="$LIBS"
LIBS="-lblkid"
AC_RUN_IFELSE([AC_LANG_PROGRAM(
[
#include <stdio.h>
#include <stdlib.h>
#include <blkid/blkid.h>
],
[
blkid_cache cache;
char *value;
if (blkid_get_cache(&cache, NULL) < 0)
return 1;
value = blkid_get_tag_value(cache, "TYPE",
"$ZFS_DEV");
if (!value) {
blkid_put_cache(cache);
return 2;
}
if (strcmp(value, "zfs_member")) {
free(value);
blkid_put_cache(cache);
return 0;
}
free(value);
blkid_put_cache(cache);
])],
[
rm -f $ZFS_DEV
AC_MSG_RESULT([yes])
AC_SUBST([LIBBLKID], ["-lblkid"])
AC_DEFINE([HAVE_LIBBLKID], 1,
[Define if you have libblkid])
],
[
rm -f $ZFS_DEV
AC_MSG_RESULT([no])
AS_IF([test "x$with_blkid" != xcheck],
[AC_MSG_FAILURE(
[--with-blkid given but unavailable])])
])
LIBS="$saved_LIBS"
],
[
AS_IF([test "x$with_blkid" != xcheck],
[AC_MSG_FAILURE(
[--with-blkid given but unavailable])])
]
[])
])
])