On Thu, Aug 26 2021, Emily Shaffer wrote:
> On Tue, Aug 24, 2021 at 04:56:10PM +0200, Ævar Arnfjörð Bjarmason wrote:
>>
>>
>> On Wed, Aug 18 2021, Emily Shaffer wrote:
>>
>> > @@ -25,7 +25,8 @@ static int run(int argc, const char **argv, const char *prefix)
>> > struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
>> > int ignore_missing = 0;
>> > const char *hook_name;
>> > - const char *hook_path;
>> > + struct list_head *hooks;
>> > +
>> > struct option run_options[] = {
>> > OPT_BOOL(0, "ignore-missing", &ignore_missing,
>> > N_("exit quietly with a zero exit code if the requested hook cannot be found")),
>>
>> In general in this patch series there's a bunch of little whitespace
>> changes like that along with other changes. I think it's probably best
>> if I just absorb that in the "base" topic instead of doing them
>> here. E.g. in this case we could also add a line between "struct option"
>> and the rest.
>>
>> I don't mind either way, but the whitespace churn makes for distracting
>> reading...
>
> Ah, hm. I don't know if in this specific case it's necessary for me to
> even have this whitespace change, since 'run_options' is still a struct
> declaration. I'll just drop this one, but in general whichever
> whitespace bits you like from this topic, feel free to absorb. Will make
> a note to scan through the diff when I rebase onto your next reroll
> checking for spurious whitespace changes.
>
>>
>> > @@ -58,15 +59,16 @@ static int run(int argc, const char **argv, const char *prefix)
>> > git_config(git_default_config, NULL);
>> >
>> > hook_name = argv[0];
>> > - if (ignore_missing)
>> > - return run_hooks_oneshot(hook_name, &opt);
>> > - hook_path = find_hook(hook_name);
>> > - if (!hook_path) {
>> > + hooks = list_hooks(hook_name);
>> > + if (list_empty(hooks)) {
>> > + /* ... act like run_hooks_oneshot() under --ignore-missing */
>> > + if (ignore_missing)
>> > + return 0;
>> > error("cannot find a hook named %s", hook_name);
>> > return 1;
>> > }
>> >
>> > - ret = run_hooks(hook_name, hook_path, &opt);
>> > + ret = run_hooks(hook_name, hooks, &opt);
>> > run_hooks_opt_clear(&opt);
>> > return ret;
>>
>> This memory management is a bit inconsistent. So here we list_hooks(),
>> pass it to run_hooks(), which clears it for us, OK...
>>
>> > -int run_hooks(const char *hook_name, const char *hook_path,
>> > - struct run_hooks_opt *options)
>> > +int run_hooks(const char *hook_name, struct list_head *hooks,
>> > + struct run_hooks_opt *options)
>> > {
>> > - struct strbuf abs_path = STRBUF_INIT;
>> > - struct hook my_hook = {
>> > - .hook_path = hook_path,
>> > - };
>> > struct hook_cb_data cb_data = {
>> > .rc = 0,
>> > .hook_name = hook_name,
>> > @@ -197,11 +241,9 @@ int run_hooks(const char *hook_name, const char *hook_path,
>> > if (!options)
>> > BUG("a struct run_hooks_opt must be provided to run_hooks");
>> >
>> > - if (options->absolute_path) {
>> > - strbuf_add_absolute_path(&abs_path, hook_path);
>> > - my_hook.hook_path = abs_path.buf;
>> > - }
>> > - cb_data.run_me = &my_hook;
>> > +
>> > + cb_data.head = hooks;
>> > + cb_data.run_me = list_first_entry(hooks, struct hook, list);
>> >
>> > run_processes_parallel_tr2(jobs,
>> > pick_next_hook,
>> > @@ -213,18 +255,15 @@ int run_hooks(const char *hook_name, const char *hook_path,
>> > "hook",
>> > hook_name);
>> >
>> > -
>> > - if (options->absolute_path)
>> > - strbuf_release(&abs_path);
>> > - free(my_hook.feed_pipe_cb_data);
>> > + clear_hook_list(hooks);
>> >
>> > return cb_data.rc;
>> > }
>>
>> Which we can see here will call clear_hook_list(), so far so good, but then...
>>
>> > int run_hooks_oneshot(const char *hook_name, struct run_hooks_opt *options)
>> > {
>> > - const char *hook_path;
>> > - int ret;
>> > + struct list_head *hooks;
>> > + int ret = 0;
>> > struct run_hooks_opt hook_opt_scratch = RUN_HOOKS_OPT_INIT;
>> >
>> > if (!options)
>> > @@ -233,14 +272,19 @@ int run_hooks_oneshot(const char *hook_name, struct run_hooks_opt *options)
>> > if (options->path_to_stdin && options->feed_pipe)
>> > BUG("choose only one method to populate stdin");
>> >
>> > - hook_path = find_hook(hook_name);
>> > - if (!hook_path) {
>> > - ret = 0;
>> > + hooks = list_hooks(hook_name);
>> > +
>> > + /*
>> > + * If you need to act on a missing hook, use run_found_hooks()
>> > + * instead
>> > + */
>> > + if (list_empty(hooks))
>> > goto cleanup;
>> > - }
>> >
>> > - ret = run_hooks(hook_name, hook_path, options);
>> > + ret = run_hooks(hook_name, hooks, options);
>> > +
>> > cleanup:
>> > run_hooks_opt_clear(options);
>> > + clear_hook_list(hooks);
>>
>> ...the oneshot command also does clear_hook_list(), after calling
>> run_hooks() which cleared it already. That looks like a mistake,
>> i.e. we should always trust run_hooks() to clear it, no?
>
> Ah, good catch. I will update the comment on run_hooks() and fix
> _oneshot() :)
>
> - Emily
I found a further memory issue with this, on "seen" running e.g. t0001
when compiled with SANITIZE=leak is broken by this series.
It's because in clear_hook_list() you clear the list of hooks, but
forget to clear the malloc'd container, so a missing free() fixes it. As
in the POC patch at the end of this mail.
But e.g. "git hook list <name>" is still broken, easy enough to fix,
just also needs fixing of the list_hooks_gently() callsites to e.g. this:
diff --git a/builtin/hook.c b/builtin/hook.c
index 50233366a8..2cd1831075 100644
--- a/builtin/hook.c
+++ b/builtin/hook.c
@@ -48,8 +48,10 @@ static int list(int argc, const char **argv, const char *prefix)
head = list_hooks_gently(hookname);
- if (list_empty(head))
+ if (list_empty(head)) {
+ clear_hook_list(head);
return 1;
+ }
list_for_each(pos, head) {
struct hook *item = list_entry(pos, struct hook, list);
Although going to that length to make the SANITIZE=leak run clean is
arguably overdoing it...
diff --git a/hook.c b/hook.c
index 23af86b9ea..e6e1e4173a 100644
--- a/hook.c
+++ b/hook.c
@@ -67,6 +67,7 @@ void clear_hook_list(struct list_head *head)
struct list_head *pos, *tmp;
list_for_each_safe(pos, tmp, head)
remove_hook(pos);
+ free(head);
}
static int known_hook(const char *name)
@@ -142,7 +143,16 @@ const char *find_hook_gently(const char *name)
int hook_exists(const char *name)
{
- return !list_empty(list_hooks(name));
+ struct list_head *hooks;
+ int exists;
+
+ hooks = list_hooks(name);
+
+ exists = !list_empty(hooks);
+
+ clear_hook_list(hooks);
+
+ return exists;
}
struct hook_config_cb
