allow disabling ACL

This patch provide option to build and run udisks without ACL.
v2: as replacement of ACL is used chown call
v3: do not change uid, change gid
v4: fix indentation & formating issues
v5: one missed empty line
v6: add g_set_error for chown

Thanks Peter Wu for helping me with improving code.

https://bugs.freedesktop.org/show_bug.cgi?id=54866

2 files changed, 43 insertions, 12 deletions

diff --git a/configure.ac b/configure.ac
index fadba1e..521502b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -183,18 +183,31 @@ if test "x$with_systemdsystemunitdir" != "xno"; then
 fi
 AM_CONDITIONAL(HAVE_SYSTEMD, [test -n "$systemdsystemunitdir"])
 
-# libacl
-AC_CHECK_HEADERS(
-        [sys/acl.h acl/libacl.h],
-        [ACL_CFLAGS=""],
-        AC_MSG_ERROR([*** ACL headers not found.]))
-AC_CHECK_LIB(
-        [acl],
-        [acl_get_file],
-        [ACL_LIBS="-lacl"],
-        AC_MSG_ERROR([*** libacl not found.]))
-AC_SUBST(ACL_CFLAGS)
-AC_SUBST(ACL_LIBS)
+have_acl=no
+AC_ARG_ENABLE(acl, AS_HELP_STRING([--disable-acl], [disable acl support]))
+if test "x$enable_acl" != "xno"; then
+  AC_CHECK_HEADERS(
+          [sys/acl.h acl/libacl.h],
+          [
+            AC_CHECK_LIB(
+                [acl],
+                [acl_get_file],
+                [AC_DEFINE(HAVE_ACL, 1, [Define if libacl is available]) have_acl=yes],
+                have_acl=no)
+          ],
+          have_acl=no)
+  if test "x$have_acl" = "xyes"; then
+    ACL_CFLAGS=""
+    ACL_LIBS="-lacl"
+  fi
+  AC_SUBST(ACL_CFLAGS)
+  AC_SUBST(ACL_LIBS)
+  if test "x$have_acl" = xno -a "x$enable_acl" = xyes; then
+    AC_MSG_ERROR([acl support requested but libraries not found])
+  fi
+fi
+AM_CONDITIONAL(HAVE_ACL, [test "$have_acl" = "yes"])
+
 
 # Internationalization
 #
@@ -242,6 +255,7 @@ echo "
         systemdsystemunitdir:       ${systemdsystemunitdir}
         using libsystemd-login:     ${have_libsystemd_login}
         use /media for mounting:    ${fhs_media}
+        acl support:                ${have_acl}
 
         compiler:                   ${CC}
         cflags:                     ${CFLAGS}
diff --git a/src/udiskslinuxfilesystem.c b/src/udiskslinuxfilesystem.c
index 4db3745..68f7c4d 100644
--- a/src/udiskslinuxfilesystem.c
+++ b/src/udiskslinuxfilesystem.c
@@ -30,7 +30,9 @@
 #include <stdio.h>
 #include <mntent.h>
 #include <sys/types.h>
+#ifdef HAVE_ACL
 #include <sys/acl.h>
+#endif
 #include <errno.h>
 
 #include <glib/gstdio.h>
@@ -803,6 +805,7 @@ ensure_utf8 (const gchar *s)
 
 /* ---------------------------------------------------------------------------------------------------- */
 
+#ifdef HAVE_ACL
 static gboolean
 add_acl (const gchar  *path,
          uid_t         uid,
@@ -835,6 +838,7 @@ add_acl (const gchar  *path,
     acl_free (acl);
   return ret;
 }
+#endif
 
 /*
  * calculate_mount_point: <internal>
@@ -912,7 +916,11 @@ calculate_mount_point (UDisksDaemon              *daemon,
               goto out;
             }
           /* Then create the per-user MOUNT_BASE/$USER */
+#ifdef HAVE_ACL
           if (g_mkdir (mount_dir, 0700) != 0 && errno != EEXIST)
+#else
+          if (g_mkdir (mount_dir, 0750) != 0 && errno != EEXIST)
+#endif
             {
               g_set_error (error,
                            UDISKS_ERROR,
@@ -922,8 +930,17 @@ calculate_mount_point (UDisksDaemon              *daemon,
               goto out;
             }
           /* Finally, add the read+execute ACL for $USER */
+#ifdef HAVE_ACL
           if (!add_acl (mount_dir, uid, error))
             {
+#else
+          if (chown (mount_dir, -1, gid) == -1)
+            {
+               g_set_error (error, G_IO_ERROR,
+                            g_io_error_from_errno (errno),
+                            "Failed to change gid to %d for %s: %m",
+                            (gint) gid, mount_dir);
+#endif
               if (rmdir (mount_dir) != 0)
                 udisks_warning ("Error calling rmdir() on %s: %m", mount_dir);
               goto out;