libattr: convert to meson

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -331,8 +331,7 @@ xen_pci_passthrough="auto"
 linux_aio="$default_feature"
 linux_io_uring="$default_feature"
 cap_ng="auto"
-attr="$default_feature"
-libattr="$default_feature"
+attr="auto"
 xfs="$default_feature"
 tcg="enabled"
 membarrier="$default_feature"
@@ -1229,9 +1228,9 @@ for opt do
   ;;
   --enable-linux-io-uring) linux_io_uring="yes"
   ;;
-  --disable-attr) attr="no"
+  --disable-attr) attr="disabled"
   ;;
-  --enable-attr) attr="yes"
+  --enable-attr) attr="enabled"
   ;;
   --disable-membarrier) membarrier="no"
   ;;
@@ -3575,36 +3574,6 @@ elif test "$tpm" = "yes"; then
   fi
 fi
 
-##########################################
-# attr probe
-
-libattr_libs=
-if test "$attr" != "no" ; then
-  cat > $TMPC <<EOF
-#include <stdio.h>
-#include <sys/types.h>
-#ifdef CONFIG_LIBATTR
-#include <attr/xattr.h>
-#else
-#include <sys/xattr.h>
-#endif
-int main(void) { getxattr(NULL, NULL, NULL, 0); setxattr(NULL, NULL, NULL, 0, 0); return 0; }
-EOF
-  if compile_prog "" "" ; then
-    attr=yes
-  # Older distros have <attr/xattr.h>, and need -lattr:
-  elif compile_prog "-DCONFIG_LIBATTR" "-lattr" ; then
-    attr=yes
-    libattr_libs="-lattr"
-    libattr=yes
-  else
-    if test "$attr" = "yes" ; then
-      feature_not_found "ATTR" "Install libc6 or libattr devel"
-    fi
-    attr=no
-  fi
-fi
-
 ##########################################
 # iovec probe
 cat > $TMPC <<EOF
@@ -5899,13 +5868,6 @@ if test "$linux_io_uring" = "yes" ; then
   echo "LINUX_IO_URING_CFLAGS=$linux_io_uring_cflags" >> $config_host_mak
   echo "LINUX_IO_URING_LIBS=$linux_io_uring_libs" >> $config_host_mak
 fi
-if test "$attr" = "yes" ; then
-  echo "CONFIG_ATTR=y" >> $config_host_mak
-  echo "LIBATTR_LIBS=$libattr_libs" >> $config_host_mak
-fi
-if test "$libattr" = "yes" ; then
-  echo "CONFIG_LIBATTR=y" >> $config_host_mak
-fi
 if test "$vhost_scsi" = "yes" ; then
   echo "CONFIG_VHOST_SCSI=y" >> $config_host_mak
 fi
@@ -6578,6 +6540,7 @@ NINJA=$ninja $meson setup \
         -Dlibnfs=$libnfs -Diconv=$iconv -Dcurses=$curses -Dlibudev=$libudev\
         -Drbd=$rbd -Dlzo=$lzo -Dsnappy=$snappy -Dlzfse=$lzfse \
         -Dzstd=$zstd -Dseccomp=$seccomp -Dvirtfs=$virtfs -Dcap_ng=$cap_ng \
+        -Dattr=$attr \
         -Ddocs=$docs -Dsphinx_build=$sphinx_build -Dinstall_blobs=$blobs \
         -Dvhost_user_blk_server=$vhost_user_blk_server \
         -Dfuse=$fuse -Dfuse_lseek=$fuse_lseek \

meson.build

@@ -328,10 +328,40 @@ if not get_option('libnfs').auto() or have_block
                       required: get_option('libnfs'),
                       method: 'pkg-config', static: enable_static)
 endif
+
+libattr_test = '''
+  #include <stddef.h>
+  #include <sys/types.h>
+  #ifdef CONFIG_LIBATTR
+  #include <attr/xattr.h>
+  #else
+  #include <sys/xattr.h>
+  #endif
+  int main(void) { getxattr(NULL, NULL, NULL, 0); setxattr(NULL, NULL, NULL, 0, 0); return 0; }'''
+
 libattr = not_found
-if 'CONFIG_ATTR' in config_host
-  libattr = declare_dependency(link_args: config_host['LIBATTR_LIBS'].split())
+have_old_libattr = false
+if not get_option('attr').disabled()
+  if cc.links(libattr_test)
+    libattr = declare_dependency()
+  else
+    libattr = cc.find_library('attr', has_headers: ['attr/xattr.h'],
+                              required: get_option('attr'),
+                              static: enable_static)
+    if libattr.found() and not \
+      cc.links(libattr_test, dependencies: libattr, args: '-DCONFIG_LIBATTR')
+      libattr = not_found
+      if get_option('attr').enabled()
+        error('could not link libattr')
+      else
+        warning('could not link libattr, disabling')
+      endif
+    else
+      have_old_libattr = libattr.found()
+    endif
+  endif
 endif
+
 seccomp = not_found
 if not get_option('seccomp').auto() or have_system or have_tools
   seccomp = dependency('libseccomp', version: '>=2.3.0',
@@ -1014,6 +1044,7 @@ config_host_data.set_quoted('CONFIG_QEMU_LOCALSTATEDIR', get_option('prefix') /
 config_host_data.set_quoted('CONFIG_QEMU_MODDIR', get_option('prefix') / qemu_moddir)
 config_host_data.set_quoted('CONFIG_SYSCONFDIR', get_option('prefix') / get_option('sysconfdir'))
 
+config_host_data.set('CONFIG_ATTR', libattr.found())
 config_host_data.set('CONFIG_BRLAPI', brlapi.found())
 config_host_data.set('CONFIG_COCOA', cocoa.found())
 config_host_data.set('CONFIG_LIBUDEV', libudev.found())
@@ -1031,6 +1062,7 @@ if glusterfs.found()
   config_host_data.set('CONFIG_GLUSTERFS_FTRUNCATE_HAS_STAT', glusterfs_ftruncate_has_stat)
   config_host_data.set('CONFIG_GLUSTERFS_IOCB_HAS_STAT', glusterfs_iocb_has_stat)
 endif
+config_host_data.set('CONFIG_LIBATTR', have_old_libattr)
 config_host_data.set('CONFIG_LIBCAP_NG', libcap_ng.found())
 config_host_data.set('CONFIG_LIBISCSI', libiscsi.found())
 config_host_data.set('CONFIG_LIBNFS', libnfs.found())
@@ -2352,7 +2384,7 @@ summary_info += {'vde support':       config_host.has_key('CONFIG_VDE')}
 summary_info += {'netmap support':    config_host.has_key('CONFIG_NETMAP')}
 summary_info += {'Linux AIO support': config_host.has_key('CONFIG_LINUX_AIO')}
 summary_info += {'Linux io_uring support': config_host.has_key('CONFIG_LINUX_IO_URING')}
-summary_info += {'ATTR/XATTR support': config_host.has_key('CONFIG_ATTR')}
+summary_info += {'ATTR/XATTR support': libattr.found()}
 summary_info += {'Install blobs':     get_option('install_blobs')}
 summary_info += {'KVM support':       config_all.has_key('CONFIG_KVM')}
 summary_info += {'HAX support':       config_all.has_key('CONFIG_HAX')}

meson_options.txt

@@ -40,6 +40,8 @@ option('cfi', type: 'boolean', value: 'false',
 option('cfi_debug', type: 'boolean', value: 'false',
        description: 'Verbose errors in case of CFI violation')
 
+option('attr', type : 'feature', value : 'auto',
+       description: 'attr/xattr support')
 option('brlapi', type : 'feature', value : 'auto',
        description: 'brlapi character device driver')
 option('bzip2', type : 'feature', value : 'auto',