[PATCH v2 2/2] builtin/repack.c: avoid dir traversal in `collect_pack_filenames()`
- From
Taylor Blau <me@ttaylorr.com>
- Date
- Jul 11, 2023, 17:32 UTC
- Message-ID
- <ffdf85f6d39c3fa2e7035deeaa0837cc58237896.1689096750.git.me@ttaylorr.com>
- In-Reply-To
- <cover.1689096750.git.me@ttaylorr.com>
When repacking, the function `collect_pack_filenames()` is responsible for collecting the set of existing packs in the repository, and partitioning them into "kept" (if the pack has a ".keep" file or was given via `--keep-pack`) and "nonkept" (otherwise) lists.
This function comes from the original C port of git-repack.sh from back in a1bbc6c0176 (repack: rewrite the shell script in C, 2013-09-15), where it first appears as `get_non_kept_pack_filenames()`. At the time, the implementation was a fairly direct translation from the relevant portion of git-repack.sh, which looped over the results of
find "$PACKDIR" -type f -name '*.pack'
either ignoring the pack as kept, or adding it to the list of existing packs.
So the choice to directly translate this function in terms of `readdir()` in a1bbc6c0176 made sense. At the time, it was possible to refine the C version in terms of packed_git structs, but was never done.
However, manually enumerating a repository's packs via `readdir()` is confusing and error-prone. It leads to frustrating inconsistencies between which packs Git considers to be part of a repository (i.e., could be found in the list of packs from `get_all_packs()`), and which packs `collect_pack_filenames()` considers to meet the same criteria.
This bit us in 73320e49ad (builtin/repack.c: only collect fully-formed packs, 2023-06-07), and again in the previous commit.
Prevent these issues from biting us in the future by implementing the `collect_pack_filenames()` function by looping over an array of pointers to `packed_git` structs, ensuring that we use the same criteria to determine the set of available packs.
One gotcha here is that we have to ignore non-local packs, since the original version of `collect_pack_filenames()` only looks at the local pack directory to collect existing packs.
Signed-off-by: Taylor Blau <me@ttaylorr.com> --- builtin/repack.c | 41 +++++++++++++++-------------------------- 1 file changed, 15 insertions(+), 26 deletions(-)
diff --git a/builtin/repack.c b/builtin/repack.c index 724e09536e..ac9fc61d2e 100644 --- a/builtin/repack.c +++ b/builtin/repack.c @@ -106,49 +106,38 @@ static void collect_pack_filenames(struct string_list *fname_nonkept_list, struct string_list *fname_kept_list, const struct string_list *extra_keep) { - DIR *dir; - struct dirent *e; - char *fname; + struct packed_git *p; struct strbuf buf = STRBUF_INIT; - if (!(dir = opendir(packdir))) - return; - - while ((e = readdir(dir)) != NULL) { - size_t len; + for (p = get_all_packs(the_repository); p; p = p->next) { int i; + const char *base; - if (!strip_suffix(e->d_name, ".idx", &len)) + if (!p->pack_local) continue; - strbuf_reset(&buf); - strbuf_add(&buf, e->d_name, len); - strbuf_addstr(&buf, ".pack"); - - if (!file_exists(mkpath("%s/%s", packdir, buf.buf))) - continue; + base = pack_basename(p); for (i = 0; i < extra_keep->nr; i++) - if (!fspathcmp(buf.buf, extra_keep->items[i].string)) + if (!fspathcmp(base, extra_keep->items[i].string)) break; - fname = xmemdupz(e->d_name, len); + strbuf_reset(&buf); + strbuf_addstr(&buf, base); + strbuf_strip_suffix(&buf, ".pack"); - if ((extra_keep->nr > 0 && i < extra_keep->nr) || - (file_exists(mkpath("%s/%s.keep", packdir, fname)))) { - string_list_append_nodup(fname_kept_list, fname); - } else { + if ((extra_keep->nr > 0 && i < extra_keep->nr) || p->pack_keep) + string_list_append(fname_kept_list, buf.buf); + else { struct string_list_item *item; - item = string_list_append_nodup(fname_nonkept_list, - fname); - if (file_exists(mkpath("%s/%s.mtimes", packdir, fname))) + item = string_list_append(fname_nonkept_list, buf.buf); + if (p->is_cruft) item->util = (void*)(uintptr_t)CRUFT_PACK; } } - closedir(dir); - strbuf_release(&buf); string_list_sort(fname_kept_list); + strbuf_release(&buf); } static void remove_redundant_pack(const char *dir_name, const char *base_name)
-- 2.41.0.329.gffdf85f6d39