Re: No fchmd. was: Re: [PATCH 00/14] Add submodule test harness

[Junio C Hamano <gitster@pobox.com>]

Torsten Bögershausen <tboegi@web.de> writes:

> On 2014-07-10 21.49, Junio C Hamano wrote:
> []
>> If we limit the case to "Inherit permissions from the file we are
>> replacing by taking a lock on it", which is the topic of discussion
>> in this thread, we do not have to worry about how to configure the
>> value (we do not have to) and adding a new parameter to tell the
>> mode to hold-lock-file-for-update is unneeded (the function will
>> have a pathname of the original and can learn the current permission
>> bits itself).
> So something like this:

Yeah, I think something along those lines may be sufficient and we
do not have to do anything when closing/committing, at least POSIX
systems.  I do not know if other filesystems we may care about let
you open with 0400 and still write into it, though.

> (I will probably not have the time to make a proper patch :-(

That's OK.  I see many names on Cc: who are all capable of helping
us ;-)

>
> diff --git a/lockfile.c b/lockfile.c
> index 4899270..134d5c8 100644
> --- a/lockfile.c
> +++ b/lockfile.c
> @@ -156,6 +156,11 @@ static void resolve_symlink(struct strbuf *path)
>  /* Make sure errno contains a meaningful value on error */
>  static int lock_file(struct lock_file *lk, const char *path, int flags)
>  {
> +       int perms = 0666;
> +       struct stat st;
> +       if (!lstat(path, &st))
> +               perms = st.st_mode & 0777;
> +
>         if (!lock_file_list) {
>                 /* One-time initialization */
>                 sigchain_push_common(remove_lock_file_on_signal);
> @@ -179,7 +184,7 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
>         if (!(flags & LOCK_NODEREF))
>                 resolve_symlink(&lk->filename);
>         strbuf_addstr(&lk->filename, LOCK_SUFFIX);
> -       lk->fd = open(lk->filename.buf, O_RDWR | O_CREAT | O_EXCL, 0666);
> +       lk->fd = open(lk->filename.buf, O_RDWR | O_CREAT | O_EXCL, perms);
>         if (lk->fd < 0) {
>                 strbuf_reset(&lk->filename);
>                 return -1;