From fc148b146ad41be71a7852c4867f0773cbfe1ff9 Mon Sep 17 00:00:00 2001 From: Emily Shaffer Date: Wed, 28 Jan 2026 23:39:26 +0200 Subject: receive-pack: convert update hooks to new API MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The hook API avoids creating a custom struct child_process and other internal hook plumbing (e.g. calling find_hook()) and prepares for the specification of hooks via configs or running parallel hooks. Execution is still sequential through the run_hooks_opt .jobs == 1, which is the unchanged default for all hooks. When use_sideband==1, the async thread redirects the hook outputs to sideband 2, otherwise it is not used and the hooks write directly to the fds inherited from the main parent process. When .jobs == 1, run-command's poll loop is avoided entirely via the ungroup=1 option like before (this was Jeff's suggestion), achieving the same real-time output performance. When running in parallel, run-command with ungroup=0 will capture and de-interleave the output of each hook, then write to the parent stderr which is redirected via dup2 to the sideband thread, so that each parallel hook output is presented clearly to the client. Signed-off-by: Emily Shaffer Signed-off-by: Ævar Arnfjörð Bjarmason Helped-by: Jeff King Signed-off-by: Adrian Ratiu Signed-off-by: Junio C Hamano --- builtin/receive-pack.c | 103 +++++++++++++++++++++++++++++++------------------ 1 file changed, 66 insertions(+), 37 deletions(-) (limited to 'builtin') diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index 9c49174616..f554dac1ef 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -561,6 +561,48 @@ static int copy_to_sideband(int in, int out UNUSED, void *arg UNUSED) return 0; } +/* + * Start an async thread which redirects hook stderr over the sideband. + * The original stderr fd is saved to `saved_stderr` and STDERR_FILENO is + * redirected to the async's input pipe. + */ +static void prepare_sideband_async(struct async *sideband_async, int *saved_stderr, int *started) +{ + *started = 0; + + if (!use_sideband) + return; + + memset(sideband_async, 0, sizeof(*sideband_async)); + sideband_async->proc = copy_to_sideband; + sideband_async->in = -1; + + if (!start_async(sideband_async)) { + *started = 1; + *saved_stderr = dup(STDERR_FILENO); + if (*saved_stderr >= 0) + dup2(sideband_async->in, STDERR_FILENO); + close(sideband_async->in); + } +} + +/* + * Restore the original stderr and wait for the async sideband thread to finish. + */ +static void finish_sideband_async(struct async *sideband_async, int saved_stderr, int started) +{ + if (!use_sideband) + return; + + if (saved_stderr >= 0) { + dup2(saved_stderr, STDERR_FILENO); + close(saved_stderr); + } + + if (started) + finish_async(sideband_async); +} + static void hmac_hash(unsigned char *out, const char *key_in, size_t key_len, const char *text, size_t text_len) @@ -941,29 +983,25 @@ static int run_receive_hook(struct command *commands, static int run_update_hook(struct command *cmd) { - struct child_process proc = CHILD_PROCESS_INIT; + struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT; + struct async sideband_async; + int sideband_async_started = 0; + int saved_stderr = -1; int code; - const char *hook_path = find_hook(the_repository, "update"); - if (!hook_path) - return 0; + strvec_pushl(&opt.args, + cmd->ref_name, + oid_to_hex(&cmd->old_oid), + oid_to_hex(&cmd->new_oid), + NULL); - strvec_push(&proc.args, hook_path); - strvec_push(&proc.args, cmd->ref_name); - strvec_push(&proc.args, oid_to_hex(&cmd->old_oid)); - strvec_push(&proc.args, oid_to_hex(&cmd->new_oid)); + prepare_sideband_async(&sideband_async, &saved_stderr, &sideband_async_started); - proc.no_stdin = 1; - proc.stdout_to_stderr = 1; - proc.err = use_sideband ? -1 : 0; - proc.trace2_hook_name = "update"; + code = run_hooks_opt(the_repository, "update", &opt); - code = start_command(&proc); - if (code) - return code; - if (use_sideband) - copy_to_sideband(proc.err, -1, NULL); - return finish_command(&proc); + finish_sideband_async(&sideband_async, saved_stderr, sideband_async_started); + + return code; } static struct command *find_command_by_refname(struct command *list, @@ -1639,34 +1677,25 @@ out: static void run_update_post_hook(struct command *commands) { + struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT; + struct async sideband_async; struct command *cmd; - struct child_process proc = CHILD_PROCESS_INIT; - const char *hook; - - hook = find_hook(the_repository, "post-update"); - if (!hook) - return; + int sideband_async_started = 0; + int saved_stderr = -1; for (cmd = commands; cmd; cmd = cmd->next) { if (cmd->error_string || cmd->did_not_exist) continue; - if (!proc.args.nr) - strvec_push(&proc.args, hook); - strvec_push(&proc.args, cmd->ref_name); + strvec_push(&opt.args, cmd->ref_name); } - if (!proc.args.nr) + if (!opt.args.nr) return; - proc.no_stdin = 1; - proc.stdout_to_stderr = 1; - proc.err = use_sideband ? -1 : 0; - proc.trace2_hook_name = "post-update"; + prepare_sideband_async(&sideband_async, &saved_stderr, &sideband_async_started); - if (!start_command(&proc)) { - if (use_sideband) - copy_to_sideband(proc.err, -1, NULL); - finish_command(&proc); - } + run_hooks_opt(the_repository, "post-update", &opt); + + finish_sideband_async(&sideband_async, saved_stderr, sideband_async_started); } static void check_aliased_update_internal(struct command *cmd, -- cgit v1.3 From b5e9ad508c2f340bd2d2547d7370ae7ac6a0d65d Mon Sep 17 00:00:00 2001 From: Emily Shaffer Date: Wed, 28 Jan 2026 23:39:27 +0200 Subject: receive-pack: convert receive hooks to hook API MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This converts the last remaining hooks to the new hook API, for the same benefits as the previous conversions (no need to toggle signals, manage custom struct child_process, call find_hook(), prepares for specifying hooks via configs, etc.). See the previous three commits for a more in-depth explanation of how this all works. Signed-off-by: Emily Shaffer Signed-off-by: Ævar Arnfjörð Bjarmason Helped-by: Jeff King Signed-off-by: Adrian Ratiu Signed-off-by: Junio C Hamano --- builtin/receive-pack.c | 178 +++++++++++++++++++++---------------------------- 1 file changed, 75 insertions(+), 103 deletions(-) (limited to 'builtin') diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index f554dac1ef..b5379a4895 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -791,7 +791,7 @@ static int check_cert_push_options(const struct string_list *push_options) return retval; } -static void prepare_push_cert_sha1(struct child_process *proc) +static void prepare_push_cert_sha1(struct run_hooks_opt *opt) { static int already_done; @@ -817,23 +817,23 @@ static void prepare_push_cert_sha1(struct child_process *proc) nonce_status = check_nonce(sigcheck.payload); } if (!is_null_oid(&push_cert_oid)) { - strvec_pushf(&proc->env, "GIT_PUSH_CERT=%s", + strvec_pushf(&opt->env, "GIT_PUSH_CERT=%s", oid_to_hex(&push_cert_oid)); - strvec_pushf(&proc->env, "GIT_PUSH_CERT_SIGNER=%s", + strvec_pushf(&opt->env, "GIT_PUSH_CERT_SIGNER=%s", sigcheck.signer ? sigcheck.signer : ""); - strvec_pushf(&proc->env, "GIT_PUSH_CERT_KEY=%s", + strvec_pushf(&opt->env, "GIT_PUSH_CERT_KEY=%s", sigcheck.key ? sigcheck.key : ""); - strvec_pushf(&proc->env, "GIT_PUSH_CERT_STATUS=%c", + strvec_pushf(&opt->env, "GIT_PUSH_CERT_STATUS=%c", sigcheck.result); if (push_cert_nonce) { - strvec_pushf(&proc->env, + strvec_pushf(&opt->env, "GIT_PUSH_CERT_NONCE=%s", push_cert_nonce); - strvec_pushf(&proc->env, + strvec_pushf(&opt->env, "GIT_PUSH_CERT_NONCE_STATUS=%s", nonce_status); if (nonce_status == NONCE_SLOP) - strvec_pushf(&proc->env, + strvec_pushf(&opt->env, "GIT_PUSH_CERT_NONCE_SLOP=%ld", nonce_stamp_slop); } @@ -845,94 +845,25 @@ struct receive_hook_feed_state { struct ref_push_report *report; int skip_broken; struct strbuf buf; - const struct string_list *push_options; }; -typedef int (*feed_fn)(void *, const char **, size_t *); -static int run_and_feed_hook(const char *hook_name, feed_fn feed, - struct receive_hook_feed_state *feed_state) +static int feed_receive_hook_cb(int hook_stdin_fd, void *pp_cb UNUSED, void *pp_task_cb) { - struct child_process proc = CHILD_PROCESS_INIT; - struct async muxer; - int code; - const char *hook_path = find_hook(the_repository, hook_name); - - if (!hook_path) - return 0; - - strvec_push(&proc.args, hook_path); - proc.in = -1; - proc.stdout_to_stderr = 1; - proc.trace2_hook_name = hook_name; - - if (feed_state->push_options) { - size_t i; - for (i = 0; i < feed_state->push_options->nr; i++) - strvec_pushf(&proc.env, - "GIT_PUSH_OPTION_%"PRIuMAX"=%s", - (uintmax_t)i, - feed_state->push_options->items[i].string); - strvec_pushf(&proc.env, "GIT_PUSH_OPTION_COUNT=%"PRIuMAX"", - (uintmax_t)feed_state->push_options->nr); - } else - strvec_pushf(&proc.env, "GIT_PUSH_OPTION_COUNT"); - - if (tmp_objdir) - strvec_pushv(&proc.env, tmp_objdir_env(tmp_objdir)); - - if (use_sideband) { - memset(&muxer, 0, sizeof(muxer)); - muxer.proc = copy_to_sideband; - muxer.in = -1; - code = start_async(&muxer); - if (code) - return code; - proc.err = muxer.in; - } - - prepare_push_cert_sha1(&proc); - - code = start_command(&proc); - if (code) { - if (use_sideband) - finish_async(&muxer); - return code; - } - - sigchain_push(SIGPIPE, SIG_IGN); - - while (1) { - const char *buf; - size_t n; - if (feed(feed_state, &buf, &n)) - break; - if (write_in_full(proc.in, buf, n) < 0) - break; - } - close(proc.in); - if (use_sideband) - finish_async(&muxer); - - sigchain_pop(SIGPIPE); - - return finish_command(&proc); -} - -static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep) -{ - struct receive_hook_feed_state *state = state_; + struct receive_hook_feed_state *state = pp_task_cb; struct command *cmd = state->cmd; + strbuf_reset(&state->buf); + while (cmd && state->skip_broken && (cmd->error_string || cmd->did_not_exist)) cmd = cmd->next; + if (!cmd) - return -1; /* EOF */ - if (!bufp) - return 0; /* OK, can feed something. */ - strbuf_reset(&state->buf); + return 1; /* no more commands left */ + if (!state->report) state->report = cmd->report; + if (state->report) { struct object_id *old_oid; struct object_id *new_oid; @@ -941,23 +872,33 @@ static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep) old_oid = state->report->old_oid ? state->report->old_oid : &cmd->old_oid; new_oid = state->report->new_oid ? state->report->new_oid : &cmd->new_oid; ref_name = state->report->ref_name ? state->report->ref_name : cmd->ref_name; + strbuf_addf(&state->buf, "%s %s %s\n", oid_to_hex(old_oid), oid_to_hex(new_oid), ref_name); + state->report = state->report->next; if (!state->report) - state->cmd = cmd->next; + cmd = cmd->next; } else { strbuf_addf(&state->buf, "%s %s %s\n", oid_to_hex(&cmd->old_oid), oid_to_hex(&cmd->new_oid), cmd->ref_name); - state->cmd = cmd->next; + cmd = cmd->next; } - if (bufp) { - *bufp = state->buf.buf; - *sizep = state->buf.len; + + state->cmd = cmd; + + if (state->buf.len > 0) { + int ret = write_in_full(hook_stdin_fd, state->buf.buf, state->buf.len); + if (ret < 0) { + if (errno == EPIPE) + return 1; /* child closed pipe */ + return ret; + } } - return 0; + + return state->cmd ? 0 : 1; /* 0 = more to come, 1 = EOF */ } static int run_receive_hook(struct command *commands, @@ -965,20 +906,51 @@ static int run_receive_hook(struct command *commands, int skip_broken, const struct string_list *push_options) { - struct receive_hook_feed_state state; - int status; + struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT; + struct command *iter = commands; + struct receive_hook_feed_state feed_state; + struct async sideband_async; + int sideband_async_started = 0; + int saved_stderr = -1; + int ret; - strbuf_init(&state.buf, 0); - state.cmd = commands; - state.skip_broken = skip_broken; - state.report = NULL; - if (feed_receive_hook(&state, NULL, NULL)) + /* if there are no valid commands, don't invoke the hook at all. */ + while (iter && skip_broken && (iter->error_string || iter->did_not_exist)) + iter = iter->next; + if (!iter) return 0; - state.cmd = commands; - state.push_options = push_options; - status = run_and_feed_hook(hook_name, feed_receive_hook, &state); - strbuf_release(&state.buf); - return status; + + if (push_options) { + for (int i = 0; i < push_options->nr; i++) + strvec_pushf(&opt.env, "GIT_PUSH_OPTION_%d=%s", i, + push_options->items[i].string); + strvec_pushf(&opt.env, "GIT_PUSH_OPTION_COUNT=%"PRIuMAX"", + (uintmax_t)push_options->nr); + } else { + strvec_push(&opt.env, "GIT_PUSH_OPTION_COUNT"); + } + + if (tmp_objdir) + strvec_pushv(&opt.env, tmp_objdir_env(tmp_objdir)); + + prepare_push_cert_sha1(&opt); + + prepare_sideband_async(&sideband_async, &saved_stderr, &sideband_async_started); + + /* set up stdin callback */ + feed_state.cmd = commands; + feed_state.skip_broken = skip_broken; + feed_state.report = NULL; + strbuf_init(&feed_state.buf, 0); + opt.feed_pipe_cb_data = &feed_state; + opt.feed_pipe = feed_receive_hook_cb; + + ret = run_hooks_opt(the_repository, hook_name, &opt); + + strbuf_release(&feed_state.buf); + finish_sideband_async(&sideband_async, saved_stderr, sideband_async_started); + + return ret; } static int run_update_hook(struct command *cmd) -- cgit v1.3 From 005f3fbe07a20dd5f7dea57f6f46cd797387e56a Mon Sep 17 00:00:00 2001 From: Adrian Ratiu Date: Mon, 2 Mar 2026 21:17:04 +0200 Subject: builtin/receive-pack: avoid spinning no-op sideband async threads Exit early if the hooks do not exist, to avoid spinning up/down sideband async threads which no-op. It is important to call the hook_exists() API provided by hook.[ch] because it covers both config-defined hooks and the "traditional" hooks from the hookdir. find_hook() only covers the hookdir hooks. The regression happened because the no-op async threads add some additional overhead which can be measured with the receive-refs test of the benchmarks suite [1]. Reproduced using: cd benchmarks/receive-refs && \ ./run --revisions /path/to/git \ fc148b146ad41be71a7852c4867f0773cbfe1ff9~,fc148b146ad41be71a7852c4867f0773cbfe1ff9 \ --parameter-list refformat reftable --parameter-list refcount 10000 1: https://gitlab.com/gitlab-org/data-access/git/benchmarks Fixes: fc148b146ad4 ("receive-pack: convert update hooks to new API") Reported-by: Patrick Steinhardt Helped-by: Jeff King Signed-off-by: Adrian Ratiu [jc: avoid duplicated hardcoded hook names] Signed-off-by: Junio C Hamano --- builtin/receive-pack.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'builtin') diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index b5379a4895..e53aaf5104 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -914,6 +914,9 @@ static int run_receive_hook(struct command *commands, int saved_stderr = -1; int ret; + if (!hook_exists(the_repository, hook_name)) + return 0; + /* if there are no valid commands, don't invoke the hook at all. */ while (iter && skip_broken && (iter->error_string || iter->did_not_exist)) iter = iter->next; @@ -955,12 +958,16 @@ static int run_receive_hook(struct command *commands, static int run_update_hook(struct command *cmd) { + static const char hook_name[] = "update"; struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT; struct async sideband_async; int sideband_async_started = 0; int saved_stderr = -1; int code; + if (!hook_exists(the_repository, hook_name)) + return 0; + strvec_pushl(&opt.args, cmd->ref_name, oid_to_hex(&cmd->old_oid), @@ -969,7 +976,7 @@ static int run_update_hook(struct command *cmd) prepare_sideband_async(&sideband_async, &saved_stderr, &sideband_async_started); - code = run_hooks_opt(the_repository, "update", &opt); + code = run_hooks_opt(the_repository, hook_name, &opt); finish_sideband_async(&sideband_async, saved_stderr, sideband_async_started); @@ -1649,12 +1656,16 @@ out: static void run_update_post_hook(struct command *commands) { + static const char hook_name[] = "post-update"; struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT; struct async sideband_async; struct command *cmd; int sideband_async_started = 0; int saved_stderr = -1; + if (!hook_exists(the_repository, hook_name)) + return; + for (cmd = commands; cmd; cmd = cmd->next) { if (cmd->error_string || cmd->did_not_exist) continue; @@ -1665,7 +1676,7 @@ static void run_update_post_hook(struct command *commands) prepare_sideband_async(&sideband_async, &saved_stderr, &sideband_async_started); - run_hooks_opt(the_repository, "post-update", &opt); + run_hooks_opt(the_repository, hook_name, &opt); finish_sideband_async(&sideband_async, saved_stderr, sideband_async_started); } -- cgit v1.3