execute: when recursively chowning StateDirectory= when spawning services, follow initial symlink

It should be OK to allow one level of symlink for the various types of
directories like StateDirectory=, LogsDirectory= and such.

src/shared/chown-recursive.c

@@ -111,12 +111,15 @@ int path_chown_recursive(
                 const char *path,
                 uid_t uid,
                 gid_t gid,
-                mode_t mask) {
+                mode_t mask,
+                int flags) {
 
         _cleanup_close_ int fd = -EBADF;
         struct stat st;
 
-        fd = open(path, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
+        assert((flags & ~AT_SYMLINK_FOLLOW) == 0);
+
+        fd = open(path, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOATIME|(FLAGS_SET(flags, AT_SYMLINK_FOLLOW) ? 0 : O_NOFOLLOW));
         if (fd < 0)
                 return -errno;
 

src/shared/chown-recursive.h

@@ -3,6 +3,6 @@
 
 #include <sys/types.h>
 
-int path_chown_recursive(const char *path, uid_t uid, gid_t gid, mode_t mask);
+int path_chown_recursive(const char *path, uid_t uid, gid_t gid, mode_t mask, int flags);
 
 int fd_chown_recursive(int fd, uid_t uid, gid_t gid, mode_t mask);