[PATCH] file-has-acl: new module, split from acl

[Paul Eggert]

And add a new module file-has-acl-tests to match.
I ran into a problem with the recent changes to the acl module,
as they introduced a typo 'test use_xattrs = 0' into 'configure'.
When using the fixed version with Emacs, I discovered that
file-has-acl wasn't separated out well enough for Emacs (e.g., it
had multiple libraries, but needed only one), so I fixed that too.
* NEWS: Document this incompatible change.
* modules/file-has-acl, modules/file-has-acl-tests: New files.
* m4/acl.m4 (gl_FUNC_ACL_ARG): New macro, split from gl_FUNC_ACL.
Initialize gl_need_lib_has_acl.
(gl_FUNC_ACL): Require it.
Simplify use of 'test'.  Set LIB_HAS_ACL if gl_need_lib_has_acl.
Move the file-has-acl.c-relevant stuff to ...
(gl_FILE_HAS_ACL): ... this new macro.  Rewrite to fix 'test
use_xattrs = 0' typo, and omit some needless work.  Set
gl_need_lib_has_acl=1 if we'll need LIB_HAS_ACL to be set
when gl_FUNC_ACL is called.
* modules/acl (Files, lib_SOURCES): Remove lib/file-has-acl.c.
(Link): Remove $(LIB_HAS_ACL).
* modules/acl-tests (Files, Depends-on, configure.ac, TESTS)
(check_PROGRAMS): Move stuff relevant to file-has-acl to
modules/file-has-acl-tests.
(test_file_has_acl_LDADD): Move to modules/file-has-acl-tests.
---
 ChangeLog                  | 25 +++++++++++++++++++
 NEWS                       |  5 ++++
 m4/acl.m4                  | 62 +++++++++++++++++++++++++++-------------------
 modules/acl                |  4 +--
 modules/acl-tests          | 10 ++------
 modules/file-has-acl       | 26 +++++++++++++++++++
 modules/file-has-acl-tests | 19 ++++++++++++++
 7 files changed, 115 insertions(+), 36 deletions(-)
 create mode 100644 modules/file-has-acl
 create mode 100644 modules/file-has-acl-tests

diff --git a/ChangeLog b/ChangeLog
index 3a067a4..b285b82 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,30 @@
 2015-04-24  Paul Eggert  <address@hidden>
 
+       file-has-acl: new module, split from acl
+       And add a new module file-has-acl-tests to match.
+       I ran into a problem with the recent changes to the acl module,
+       as they introduced a typo 'test use_xattrs = 0' into 'configure'.
+       When using the fixed version with Emacs, I discovered that
+       file-has-acl wasn't separated out well enough for Emacs (e.g., it
+       had multiple libraries, but needed only one), so I fixed that too.
+       * NEWS: Document this incompatible change.
+       * modules/file-has-acl, modules/file-has-acl-tests: New files.
+       * m4/acl.m4 (gl_FUNC_ACL_ARG): New macro, split from gl_FUNC_ACL.
+       Initialize gl_need_lib_has_acl.
+       (gl_FUNC_ACL): Require it.
+       Simplify use of 'test'.  Set LIB_HAS_ACL if gl_need_lib_has_acl.
+       Move the file-has-acl.c-relevant stuff to ...
+       (gl_FILE_HAS_ACL): ... this new macro.  Rewrite to fix 'test
+       use_xattrs = 0' typo, and omit some needless work.  Set
+       gl_need_lib_has_acl=1 if we'll need LIB_HAS_ACL to be set
+       when gl_FUNC_ACL is called.
+       * modules/acl (Files, lib_SOURCES): Remove lib/file-has-acl.c.
+       (Link): Remove $(LIB_HAS_ACL).
+       * modules/acl-tests (Files, Depends-on, configure.ac, TESTS)
+       (check_PROGRAMS): Move stuff relevant to file-has-acl to
+       modules/file-has-acl-tests.
+       (test_file_has_acl_LDADD): Move to modules/file-has-acl-tests.
+
        manywarnings: add GCC 5.1 warnings
        * build-aux/gcc-warning.spec: Add -Wabi=, -Warray-bounds,
        -Warray-bounds=, -Wc++14-compat, -Wc90-c99-compat,
diff --git a/NEWS b/NEWS
index fd15999..1e36206 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,11 @@ Important notes
 
 Date        Modules         Changes
 
+2015-04-24  acl             This module no longer defines file_has_acl.
+                            Use the new file-has-acl module for that.
+                            Using only the latter module makes for fewer
+                            link-time dependencies on GNU/Linux.
+
 2015-04-15  acl             If your project only uses the file_has_acl()
                             detection routine, then the requirements are
                             potentially reduced by using $LIB_HAS_ACL rather
diff --git a/m4/acl.m4 b/m4/acl.m4
index a6c2a0d..186353c 100644
--- a/m4/acl.m4
+++ b/m4/acl.m4
@@ -1,5 +1,5 @@
 # acl.m4 - check for access control list (ACL) primitives
-# serial 17
+# serial 18
 
 # Copyright (C) 2002, 2004-2015 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -8,24 +8,29 @@
 
 # Written by Paul Eggert and Jim Meyering.
 
-AC_DEFUN([gl_FUNC_ACL],
+AC_DEFUN([gl_FUNC_ACL_ARG],
 [
+  gl_need_lib_has_acl=
   AC_ARG_ENABLE([acl],
     AS_HELP_STRING([--disable-acl], [do not support ACLs]),
     , [enable_acl=auto])
+])
 
+
+AC_DEFUN([gl_FUNC_ACL],
+[
+  AC_REQUIRE([gl_FUNC_ACL_ARG])
   AC_CHECK_FUNCS_ONCE([fchmod])
   LIB_ACL=
-  LIB_HAS_ACL=
   use_acl=0
-  if test "x$enable_acl" != "xno"; then
+  if test "$enable_acl" != no; then
     dnl On all platforms, the ACL related API is declared in <sys/acl.h>.
     AC_CHECK_HEADERS([sys/acl.h])
     if test $ac_cv_header_sys_acl_h = yes; then
       ac_save_LIBS=$LIBS
 
-      dnl Test for POSIX-draft-like API (Linux, FreeBSD, Mac OS X, IRIX, 
Tru64).
-      dnl -lacl is needed on Linux, -lpacl is needed on OSF/1.
+      dnl Test for POSIX-draft-like API (GNU/Linux, FreeBSD, Mac OS X,
+      dnl IRIX, Tru64).  -lacl is needed on GNU/Linux, -lpacl on OSF/1.
       if test $use_acl = 0; then
         AC_SEARCH_LIBS([acl_get_file], [acl pacl],
           [if test "$ac_cv_search_acl_get_file" != "none required"; then
@@ -41,7 +46,7 @@ AC_DEFUN([gl_FUNC_ACL],
            # If the acl_get_file bug is detected, don't enable the ACL support.
            gl_ACL_GET_FILE([use_acl=1], [])
            if test $use_acl = 1; then
-             dnl On Linux, additional API is declared in <acl/libacl.h>.
+             dnl On GNU/Linux, an additional API is declared in <acl/libacl.h>.
              AC_CHECK_HEADERS([acl/libacl.h])
              AC_REPLACE_FUNCS([acl_entries])
              AC_CACHE_CHECK([for ACL_FIRST_ENTRY],
@@ -126,29 +131,15 @@ int type = ACL_TYPE_EXTENDED;]])],
       LIBS=$ac_save_LIBS
     fi
 
-    dnl On Linux, testing if a file has an acl can be done with the getxattr
-    dnl syscall which doesn't require linking against additional libraries.
-    use_xattrs=0
-    AC_CHECK_HEADERS([sys/xattr.h linux/xattr.h])
-    if test $ac_cv_header_sys_xattr_h = yes && test 
$ac_cv_header_linux_xattr_h = yes; then
-      AC_CHECK_FUNCS([getxattr])
-      if test $ac_cv_func_getxattr = yes; then
-       use_xattrs=1
-      fi
-    fi
-    if test use_xattrs = 0; then
-      LIB_HAS_ACL=$LIB_ACL
-    fi
-
-    if test "x$enable_acl$use_acl" = "xyes0"; then
+    if test "$enable_acl$use_acl" = yes0; then
       AC_MSG_ERROR([ACLs enabled but support not detected])
-    elif test "x$enable_acl$use_acl" = "xauto0"; then
+    elif test "$enable_acl$use_acl" = auto0; then
       AC_MSG_WARN([libacl development library was not found or not usable.])
       AC_MSG_WARN([AC_PACKAGE_NAME will be built without ACL support.])
     fi
   fi
+  test $gl_need_lib_has_acl && LIB_HAS_ACL=$LIB_ACL
   AC_SUBST([LIB_ACL])
-  AC_SUBST([LIB_HAS_ACL])
   AC_DEFINE_UNQUOTED([USE_ACL], [$use_acl],
     [Define to nonzero if you want access control list support.])
   USE_ACL=$use_acl
@@ -156,7 +147,7 @@ int type = ACL_TYPE_EXTENDED;]])],
 ])
 
 # gl_ACL_GET_FILE(IF-WORKS, IF-NOT)
-# -------------------------------------
+# ---------------------------------
 # If 'acl_get_file' works (does not have a particular bug),
 # run IF-WORKS, otherwise, IF-NOT.
 # When building natively, test for a Darwin 8.7.0 bug, whereby acl_get_file
@@ -183,3 +174,24 @@ AC_DEFUN([gl_ACL_GET_FILE],
         fi])])
   AS_IF([test "$gl_cv_func_working_acl_get_file" != no], [$1], [$2])
 ])
+
+# On GNU/Linux, testing if a file has an acl can be done with the getxattr
+# syscall which doesn't require linking against additional libraries.
+AC_DEFUN([gl_FILE_HAS_ACL],
+[
+  AC_REQUIRE([gl_FUNC_ACL_ARG])
+  if test "$enable_acl" != no; then
+    AC_CHECK_HEADERS([linux/xattr.h],
+      [AC_CHECK_HEADERS([sys/xattr.h],
+         [AC_CHECK_FUNCS([getxattr])])])
+  fi
+  if test 
"$ac_cv_header_sys_xattr_h,$ac_cv_header_linux_xattr_h,$ac_cv_func_getxattr" = 
yes,yes,yes; then
+    LIB_HAS_ACL=
+  else
+    dnl Set gl_need_lib_has_acl to a nonempty value, so that any
+    dnl later gl_FUNC_ACL call will set LIB_HAS_ACL=$LIB_ACL.
+    gl_need_lib_has_acl=1
+    LIB_HAS_ACL=$LIB_ACL
+  fi
+  AC_SUBST([LIB_HAS_ACL])
+])
diff --git a/modules/acl b/modules/acl
index 7faec17..d5d3450 100644
--- a/modules/acl
+++ b/modules/acl
@@ -2,7 +2,6 @@ Description:
 Access control lists of files, with diagnostics.  (Unportable.)
 
 Files:
-lib/file-has-acl.c
 lib/copy-acl.c
 lib/set-acl.c
 
@@ -16,14 +15,13 @@ stdbool
 configure.ac:
 
 Makefile.am:
-lib_SOURCES += file-has-acl.c copy-acl.c set-acl.c
+lib_SOURCES += copy-acl.c set-acl.c
 
 Include:
 "acl.h"
 
 Link:
 $(LIB_ACL)
-$(LIB_HAS_ACL)
 
 License:
 GPL
diff --git a/modules/acl-tests b/modules/acl-tests
index 36908b3..e755014 100644
--- a/modules/acl-tests
+++ b/modules/acl-tests
@@ -1,36 +1,30 @@
 Files:
-tests/test-file-has-acl.sh
-tests/test-file-has-acl-1.sh
-tests/test-file-has-acl-2.sh
 tests/test-set-mode-acl.sh
 tests/test-set-mode-acl-1.sh
 tests/test-set-mode-acl-2.sh
 tests/test-copy-acl.sh
 tests/test-copy-acl-1.sh
 tests/test-copy-acl-2.sh
-tests/test-file-has-acl.c
 tests/test-set-mode-acl.c
 tests/test-copy-acl.c
 tests/test-sameacls.c
 tests/macros.h
 
 Depends-on:
+file-has-acl-tests
 progname
 read-file
 unistd
 xalloc
 
 configure.ac:
-AC_CHECK_DECLS_ONCE([alarm])
 
 Makefile.am:
 TESTS += \
-  test-file-has-acl.sh test-file-has-acl-1.sh test-file-has-acl-2.sh \
   test-set-mode-acl.sh test-set-mode-acl-1.sh test-set-mode-acl-2.sh \
   test-copy-acl.sh test-copy-acl-1.sh test-copy-acl-2.sh
 TESTS_ENVIRONMENT += USE_ACL=$(USE_ACL)
-check_PROGRAMS += test-file-has-acl test-set-mode-acl test-copy-acl 
test-sameacls
-test_file_has_acl_LDADD = $(LDADD) $(LIB_ACL)
+check_PROGRAMS += test-set-mode-acl test-copy-acl test-sameacls
 test_set_mode_acl_LDADD = $(LDADD) $(LIB_ACL) @LIBINTL@
 test_copy_acl_LDADD = $(LDADD) $(LIB_ACL) @LIBINTL@
 test_sameacls_LDADD = $(LDADD) $(LIB_ACL) @LIBINTL@
diff --git a/modules/file-has-acl b/modules/file-has-acl
new file mode 100644
index 0000000..b602dc5
--- /dev/null
+++ b/modules/file-has-acl
@@ -0,0 +1,26 @@
+Description:
+Whether a file has an ACL.
+
+Files:
+lib/file-has-acl.c
+
+Depends-on:
+qacl  [test $gl_need_lib_has_acl]
+
+configure.ac:
+gl_FILE_HAS_ACL
+
+Makefile.am:
+lib_SOURCES += file-has-acl.c
+
+Include:
+"acl.h"
+
+Link:
+$(LIB_HAS_ACL)
+
+License:
+GPL
+
+Maintainer:
+Paul Eggert, Jim Meyering
diff --git a/modules/file-has-acl-tests b/modules/file-has-acl-tests
new file mode 100644
index 0000000..5a26020
--- /dev/null
+++ b/modules/file-has-acl-tests
@@ -0,0 +1,19 @@
+Files:
+tests/test-file-has-acl.sh
+tests/test-file-has-acl-1.sh
+tests/test-file-has-acl-2.sh
+tests/test-file-has-acl.c
+tests/macros.h
+
+Depends-on:
+unistd
+
+configure.ac:
+AC_CHECK_DECLS_ONCE([alarm])
+
+Makefile.am:
+TESTS += \
+  test-file-has-acl.sh test-file-has-acl-1.sh test-file-has-acl-2.sh
+TESTS_ENVIRONMENT += USE_ACL=$(USE_ACL)
+check_PROGRAMS += test-file-has-acl
+test_file_has_acl_LDADD = $(LDADD) $(LIB_HAS_ACL)
-- 
2.1.0