Fix bug with lock file on nonstandard filesystem

* src/filelock.c (create_lock_file):
Don’t disable user write access to the lock file (Bug#37884).

1 files changed, 7 insertions, 1 deletions

diff --git a/src/filelock.c b/src/filelock.c
index ff25d6475de..2077287345c 100644
--- a/src/filelock.c
+++ b/src/filelock.c
@@ -402,9 +402,15 @@ create_lock_file (char *lfname, char *lock_info_str, bool force)
           ptrdiff_t lock_info_len;
           lock_info_len = strlen (lock_info_str);
           err = 0;
+
+          /* Make the lock file readable to others, so that others' sessions
+             can read it.  Even though nobody should write to the lock file,
+             keep it user-writable to work around problems on nonstandard file
+             systems that prohibit unlinking readonly files (Bug#37884).  */
           if (emacs_write (fd, lock_info_str, lock_info_len) != lock_info_len
-              || fchmod (fd, S_IRUSR | S_IRGRP | S_IROTH) != 0)
+              || fchmod (fd, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) != 0)
             err = errno;
+
           /* There is no need to call fsync here, as the contents of
              the lock file need not survive system crashes.  */
           if (emacs_close (fd) != 0)