git-commit-vandalism/list-objects.c
Ævar Arnfjörð Bjarmason 4f33a6345f list-objects: handle NULL function pointers
If a caller to traverse_commit_list() specifies the options for the
--objects flag but does not specify a show_object function pointer, the
result is a segfault. This is currently visible by running 'git bundle
create --objects HEAD'.

We could fix this problem by supplying a no-op callback in
builtin/bundle.c, but that only solves the problem for one builtin,
leaving this segfault open for other callers.

Replace all callers of the show_commit and show_object function pointers
in list-objects.c to call helper functions show_commit() and
show_object() which check that the given context has non-NULL functions
before passing the necessary data. One extra benefit is that it reduces
duplication due to passing ctx->show_data to every caller.

Test that this segfault no longer occurs for 'git bundle'.

Co-authored-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-09 10:25:27 -08:00

458 lines
12 KiB
C

#include "cache.h"
#include "tag.h"
#include "commit.h"
#include "tree.h"
#include "blob.h"
#include "diff.h"
#include "tree-walk.h"
#include "revision.h"
#include "list-objects.h"
#include "list-objects-filter.h"
#include "list-objects-filter-options.h"
#include "packfile.h"
#include "object-store.h"
#include "trace.h"
struct traversal_context {
struct rev_info *revs;
show_object_fn show_object;
show_commit_fn show_commit;
void *show_data;
struct filter *filter;
};
static void show_commit(struct traversal_context *ctx,
struct commit *commit)
{
if (!ctx->show_commit)
return;
ctx->show_commit(commit, ctx->show_data);
}
static void show_object(struct traversal_context *ctx,
struct object *object,
const char *name)
{
if (!ctx->show_object)
return;
ctx->show_object(object, name, ctx->show_data);
}
static void process_blob(struct traversal_context *ctx,
struct blob *blob,
struct strbuf *path,
const char *name)
{
struct object *obj = &blob->object;
size_t pathlen;
enum list_objects_filter_result r;
if (!ctx->revs->blob_objects)
return;
if (!obj)
die("bad blob object");
if (obj->flags & (UNINTERESTING | SEEN))
return;
/*
* Pre-filter known-missing objects when explicitly requested.
* Otherwise, a missing object error message may be reported
* later (depending on other filtering criteria).
*
* Note that this "--exclude-promisor-objects" pre-filtering
* may cause the actual filter to report an incomplete list
* of missing objects.
*/
if (ctx->revs->exclude_promisor_objects &&
!has_object_file(&obj->oid) &&
is_promisor_object(&obj->oid))
return;
pathlen = path->len;
strbuf_addstr(path, name);
r = list_objects_filter__filter_object(ctx->revs->repo,
LOFS_BLOB, obj,
path->buf, &path->buf[pathlen],
ctx->filter);
if (r & LOFR_MARK_SEEN)
obj->flags |= SEEN;
if (r & LOFR_DO_SHOW)
show_object(ctx, obj, path->buf);
strbuf_setlen(path, pathlen);
}
/*
* Processing a gitlink entry currently does nothing, since
* we do not recurse into the subproject.
*
* We *could* eventually add a flag that actually does that,
* which would involve:
* - is the subproject actually checked out?
* - if so, see if the subproject has already been added
* to the alternates list, and add it if not.
* - process the commit (or tag) the gitlink points to
* recursively.
*
* However, it's unclear whether there is really ever any
* reason to see superprojects and subprojects as such a
* "unified" object pool (potentially resulting in a totally
* humongous pack - avoiding which was the whole point of
* having gitlinks in the first place!).
*
* So for now, there is just a note that we *could* follow
* the link, and how to do it. Whether it necessarily makes
* any sense what-so-ever to ever do that is another issue.
*/
static void process_gitlink(struct traversal_context *ctx,
const unsigned char *sha1,
struct strbuf *path,
const char *name)
{
/* Nothing to do */
}
static void process_tree(struct traversal_context *ctx,
struct tree *tree,
struct strbuf *base,
const char *name);
static void process_tree_contents(struct traversal_context *ctx,
struct tree *tree,
struct strbuf *base)
{
struct tree_desc desc;
struct name_entry entry;
enum interesting match = ctx->revs->diffopt.pathspec.nr == 0 ?
all_entries_interesting : entry_not_interesting;
init_tree_desc(&desc, tree->buffer, tree->size);
while (tree_entry(&desc, &entry)) {
if (match != all_entries_interesting) {
match = tree_entry_interesting(ctx->revs->repo->index,
&entry, base, 0,
&ctx->revs->diffopt.pathspec);
if (match == all_entries_not_interesting)
break;
if (match == entry_not_interesting)
continue;
}
if (S_ISDIR(entry.mode)) {
struct tree *t = lookup_tree(ctx->revs->repo, &entry.oid);
if (!t) {
die(_("entry '%s' in tree %s has tree mode, "
"but is not a tree"),
entry.path, oid_to_hex(&tree->object.oid));
}
t->object.flags |= NOT_USER_GIVEN;
process_tree(ctx, t, base, entry.path);
}
else if (S_ISGITLINK(entry.mode))
process_gitlink(ctx, entry.oid.hash,
base, entry.path);
else {
struct blob *b = lookup_blob(ctx->revs->repo, &entry.oid);
if (!b) {
die(_("entry '%s' in tree %s has blob mode, "
"but is not a blob"),
entry.path, oid_to_hex(&tree->object.oid));
}
b->object.flags |= NOT_USER_GIVEN;
process_blob(ctx, b, base, entry.path);
}
}
}
static void process_tree(struct traversal_context *ctx,
struct tree *tree,
struct strbuf *base,
const char *name)
{
struct object *obj = &tree->object;
struct rev_info *revs = ctx->revs;
int baselen = base->len;
enum list_objects_filter_result r;
int failed_parse;
if (!revs->tree_objects)
return;
if (!obj)
die("bad tree object");
if (obj->flags & (UNINTERESTING | SEEN))
return;
if (revs->include_check_obj &&
!revs->include_check_obj(&tree->object, revs->include_check_data))
return;
failed_parse = parse_tree_gently(tree, 1);
if (failed_parse) {
if (revs->ignore_missing_links)
return;
/*
* Pre-filter known-missing tree objects when explicitly
* requested. This may cause the actual filter to report
* an incomplete list of missing objects.
*/
if (revs->exclude_promisor_objects &&
is_promisor_object(&obj->oid))
return;
if (!revs->do_not_die_on_missing_tree)
die("bad tree object %s", oid_to_hex(&obj->oid));
}
strbuf_addstr(base, name);
r = list_objects_filter__filter_object(ctx->revs->repo,
LOFS_BEGIN_TREE, obj,
base->buf, &base->buf[baselen],
ctx->filter);
if (r & LOFR_MARK_SEEN)
obj->flags |= SEEN;
if (r & LOFR_DO_SHOW)
show_object(ctx, obj, base->buf);
if (base->len)
strbuf_addch(base, '/');
if (r & LOFR_SKIP_TREE)
trace_printf("Skipping contents of tree %s...\n", base->buf);
else if (!failed_parse)
process_tree_contents(ctx, tree, base);
r = list_objects_filter__filter_object(ctx->revs->repo,
LOFS_END_TREE, obj,
base->buf, &base->buf[baselen],
ctx->filter);
if (r & LOFR_MARK_SEEN)
obj->flags |= SEEN;
if (r & LOFR_DO_SHOW)
show_object(ctx, obj, base->buf);
strbuf_setlen(base, baselen);
free_tree_buffer(tree);
}
static void process_tag(struct traversal_context *ctx,
struct tag *tag,
const char *name)
{
enum list_objects_filter_result r;
r = list_objects_filter__filter_object(ctx->revs->repo, LOFS_TAG,
&tag->object, NULL, NULL,
ctx->filter);
if (r & LOFR_MARK_SEEN)
tag->object.flags |= SEEN;
if (r & LOFR_DO_SHOW)
show_object(ctx, &tag->object, name);
}
static void mark_edge_parents_uninteresting(struct commit *commit,
struct rev_info *revs,
show_edge_fn show_edge)
{
struct commit_list *parents;
for (parents = commit->parents; parents; parents = parents->next) {
struct commit *parent = parents->item;
if (!(parent->object.flags & UNINTERESTING))
continue;
mark_tree_uninteresting(revs->repo, get_commit_tree(parent));
if (revs->edge_hint && !(parent->object.flags & SHOWN)) {
parent->object.flags |= SHOWN;
show_edge(parent);
}
}
}
static void add_edge_parents(struct commit *commit,
struct rev_info *revs,
show_edge_fn show_edge,
struct oidset *set)
{
struct commit_list *parents;
for (parents = commit->parents; parents; parents = parents->next) {
struct commit *parent = parents->item;
struct tree *tree = get_commit_tree(parent);
if (!tree)
continue;
oidset_insert(set, &tree->object.oid);
if (!(parent->object.flags & UNINTERESTING))
continue;
tree->object.flags |= UNINTERESTING;
if (revs->edge_hint && !(parent->object.flags & SHOWN)) {
parent->object.flags |= SHOWN;
show_edge(parent);
}
}
}
void mark_edges_uninteresting(struct rev_info *revs,
show_edge_fn show_edge,
int sparse)
{
struct commit_list *list;
int i;
if (sparse) {
struct oidset set;
oidset_init(&set, 16);
for (list = revs->commits; list; list = list->next) {
struct commit *commit = list->item;
struct tree *tree = get_commit_tree(commit);
if (commit->object.flags & UNINTERESTING)
tree->object.flags |= UNINTERESTING;
oidset_insert(&set, &tree->object.oid);
add_edge_parents(commit, revs, show_edge, &set);
}
mark_trees_uninteresting_sparse(revs->repo, &set);
oidset_clear(&set);
} else {
for (list = revs->commits; list; list = list->next) {
struct commit *commit = list->item;
if (commit->object.flags & UNINTERESTING) {
mark_tree_uninteresting(revs->repo,
get_commit_tree(commit));
if (revs->edge_hint_aggressive && !(commit->object.flags & SHOWN)) {
commit->object.flags |= SHOWN;
show_edge(commit);
}
continue;
}
mark_edge_parents_uninteresting(commit, revs, show_edge);
}
}
if (revs->edge_hint_aggressive) {
for (i = 0; i < revs->cmdline.nr; i++) {
struct object *obj = revs->cmdline.rev[i].item;
struct commit *commit = (struct commit *)obj;
if (obj->type != OBJ_COMMIT || !(obj->flags & UNINTERESTING))
continue;
mark_tree_uninteresting(revs->repo,
get_commit_tree(commit));
if (!(obj->flags & SHOWN)) {
obj->flags |= SHOWN;
show_edge(commit);
}
}
}
}
static void add_pending_tree(struct rev_info *revs, struct tree *tree)
{
add_pending_object(revs, &tree->object, "");
}
static void traverse_non_commits(struct traversal_context *ctx,
struct strbuf *base)
{
int i;
assert(base->len == 0);
for (i = 0; i < ctx->revs->pending.nr; i++) {
struct object_array_entry *pending = ctx->revs->pending.objects + i;
struct object *obj = pending->item;
const char *name = pending->name;
const char *path = pending->path;
if (obj->flags & (UNINTERESTING | SEEN))
continue;
if (obj->type == OBJ_TAG) {
process_tag(ctx, (struct tag *)obj, name);
continue;
}
if (!path)
path = "";
if (obj->type == OBJ_TREE) {
process_tree(ctx, (struct tree *)obj, base, path);
continue;
}
if (obj->type == OBJ_BLOB) {
process_blob(ctx, (struct blob *)obj, base, path);
continue;
}
die("unknown pending object %s (%s)",
oid_to_hex(&obj->oid), name);
}
object_array_clear(&ctx->revs->pending);
}
static void do_traverse(struct traversal_context *ctx)
{
struct commit *commit;
struct strbuf csp; /* callee's scratch pad */
strbuf_init(&csp, PATH_MAX);
while ((commit = get_revision(ctx->revs)) != NULL) {
enum list_objects_filter_result r;
r = list_objects_filter__filter_object(ctx->revs->repo,
LOFS_COMMIT, &commit->object,
NULL, NULL, ctx->filter);
/*
* an uninteresting boundary commit may not have its tree
* parsed yet, but we are not going to show them anyway
*/
if (!ctx->revs->tree_objects)
; /* do not bother loading tree */
else if (get_commit_tree(commit)) {
struct tree *tree = get_commit_tree(commit);
tree->object.flags |= NOT_USER_GIVEN;
add_pending_tree(ctx->revs, tree);
} else if (commit->object.parsed) {
die(_("unable to load root tree for commit %s"),
oid_to_hex(&commit->object.oid));
}
if (r & LOFR_MARK_SEEN)
commit->object.flags |= SEEN;
if (r & LOFR_DO_SHOW)
show_commit(ctx, commit);
if (ctx->revs->tree_blobs_in_commit_order)
/*
* NEEDSWORK: Adding the tree and then flushing it here
* needs a reallocation for each commit. Can we pass the
* tree directory without allocation churn?
*/
traverse_non_commits(ctx, &csp);
}
traverse_non_commits(ctx, &csp);
strbuf_release(&csp);
}
void traverse_commit_list_filtered(
struct rev_info *revs,
show_commit_fn show_commit,
show_object_fn show_object,
void *show_data,
struct oidset *omitted)
{
struct traversal_context ctx = {
.revs = revs,
.show_object = show_object,
.show_commit = show_commit,
.show_data = show_data,
};
if (revs->filter.choice)
ctx.filter = list_objects_filter__init(omitted, &revs->filter);
do_traverse(&ctx);
if (ctx.filter)
list_objects_filter__free(ctx.filter);
}