read-cache: use shared perms when writing shared index

Since f6ecc62dbf (write_shared_index(): use tempfile module, 2015-08-10)
write_shared_index() has been using mks_tempfile() to create the
temporary file that will become the shared index.

But even before that, it looks like the functions used to create this
file didn't call adjust_shared_perm(), which means that the shared
index file has always been created with 600 permissions regardless
of the shared permission settings.

Because of that, on repositories created with `git init --shared=all`
and using the split index feature, one gets an error like:

fatal: .git/sharedindex.a52f910b489bc462f187ab572ba0086f7b5157de: index file open failed: Permission denied

when another user performs any operation that reads the shared index.

Call adjust_shared_perm() on the temporary file created by
mks_tempfile() ourselves to adjust the permission bits.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/read-cache.c b/read-cache.c
index f12da0d..6238df4 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -2428,6 +2428,14 @@ static int write_shared_index(struct index_state *istate,
                delete_tempfile(&temporary_sharedindex);
                return ret;
        }
+       ret = adjust_shared_perm(get_tempfile_path(&temporary_sharedindex));
+       if (ret) {
+               int save_errno = errno;
+               error("cannot fix permission bits on %s", get_tempfile_path(&temporary_sharedindex));
+               delete_tempfile(&temporary_sharedindex);
+               errno = save_errno;
+               return ret;
+       }
        ret = rename_tempfile(&temporary_sharedindex,
                              git_path("sharedindex.%s", sha1_to_hex(si->base->sha1)));
        if (!ret) {