acl-util: add new inode_type_can_acl() helper

src/shared/acl-util.c

@@ -648,3 +648,7 @@ int fd_acl_make_writable_fallback(int fd) {
 
         return 1;
 }
+
+int inode_type_can_acl(mode_t mode) {
+        return IN_SET(mode & S_IFMT, S_IFSOCK, S_IFREG, S_IFBLK, S_IFCHR, S_IFDIR, S_IFIFO);
+}

src/shared/acl-util.h

@@ -53,3 +53,5 @@ static inline int fd_acl_make_writable(int fd) {
 }
 
 #endif
+
+int inode_type_can_acl(mode_t mode);

src/shared/shift-uid.c

@@ -161,7 +161,7 @@ static int patch_acls(int fd, const char *name, const struct stat *st, uid_t shi
         assert(st);
 
         /* ACLs are not supported on symlinks, there's no point in trying */
-        if (S_ISLNK(st->st_mode))
+        if (!inode_type_can_acl(st->st_mode))
                 return 0;
 
         r = get_acl(fd, name, ACL_TYPE_ACCESS, &acl);

src/tmpfiles/tmpfiles.c

@@ -1459,8 +1459,8 @@ static int fd_set_acls(
                                        "Refusing to set ACLs on hardlinked file %s while the fs.protected_hardlinks sysctl is turned off.",
                                        path);
 
-        if (S_ISLNK(st->st_mode)) {
-                log_debug("Skipping ACL fix for symlink %s.", path);
+        if (!inode_type_can_acl(st->st_mode)) {
+                log_debug("Skipping ACL fix for '%s' (inode type does not support ACLs).", path);
                 return 0;
         }