[PATCH 3/5] fast-import: clean up pack_data pointer in end_packfile
- From
Jeff King <peff@peff.net>
- Date
- Aug 23, 2014, 05:27 UTC
- Message-ID
- <20140823052741.GC18075@peff.net>
- In-Reply-To
- <20140823052334.GA17813@peff.net>
We have a global pointer pack_data pointing to the current pack we have open. Inside end_packfile we have two new pointers, old_p and new_p. The latter points to pack_data, and the former points to the new "installed" version of the packfile we get when we hand the file off to the regular sha1_file machinery. When then free old_p.
Presumably the extra old_p pointer was there so that we could overwrite pack_data with new_p and still free old_p, but we don't do that. We just leave pack_data pointing to bogus memory, and don't overwrite it until we call start_packfile again (if ever).
This can cause problems for our die routine, which calls end_packfile to clean things up. If we die at the wrong moment, we can end up looking at invalid memory in pack_data left after the last end_packfile().
Instead, let's make sure we set pack_data to NULL after we free it, and make calling endfile() again with a NULL pack_data a noop (there is nothing to end).
We can further make things less confusing by dropping old_p entirely, and moving new_p closer to its point of use.
Signed-off-by: Jeff King <peff@peff.net> --- Noticed while running fast-import under valgrind to debug the next commit. :)
fast-import.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/fast-import.c b/fast-import.c index d73f58c..f25a4ae 100644 --- a/fast-import.c +++ b/fast-import.c @@ -946,10 +946,12 @@ static void unkeep_all_packs(void) static void end_packfile(void) { - struct packed_git *old_p = pack_data, *new_p; + if (!pack_data) + return; clear_delta_base_cache(); if (object_count) { + struct packed_git *new_p; unsigned char cur_pack_sha1[20]; char *idx_name; int i; @@ -991,10 +993,11 @@ static void end_packfile(void) pack_id++; } else { - close(old_p->pack_fd); - unlink_or_warn(old_p->pack_name); + close(pack_data->pack_fd); + unlink_or_warn(pack_data->pack_name); } - free(old_p); + free(pack_data); + pack_data = NULL; /* We can't carry a delta across packfiles. */ strbuf_release(&last_blob.data);
-- 2.1.0.346.ga0367b9