[14/27] run-command: allow stdin for run_processes_parallel

Message ID	patch-14.27-477d75bf57-20210617T101217Z-avarab@gmail.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <git-owner@kernel.org> From: =?utf-8?b?w4Z2YXIgQXJuZmrDtnLDsCBCamFybWFzb24=?= <avarab@gmail.com> To: git@vger.kernel.org Cc: Junio C Hamano <gitster@pobox.com>, Emily Shaffer <emilyshaffer@google.com>, Jeff King <peff@peff.net>, Taylor Blau <me@ttaylorr.com>, Felipe Contreras <felipe.contreras@gmail.com>, Eric Sunshine <sunshine@sunshineco.com>, "brian m . carlson" <sandals@crustytoothpaste.net>, Josh Steadmon <steadmon@google.com>, Jonathan Tan <jonathantanmy@google.com>, Derrick Stolee <stolee@gmail.com>, =?utf-8?b?w4Z2YXIgQXJuZmrDtnLDsCBCamFy?= =?utf-8?b?bWFzb24=?= <avarab@gmail.com> Subject: [PATCH 14/27] run-command: allow stdin for run_processes_parallel Date: Thu, 17 Jun 2021 12:22:48 +0200 Message-Id: <patch-14.27-477d75bf57-20210617T101217Z-avarab@gmail.com> In-Reply-To: <cover-00.27-0000000000-20210617T101216Z-avarab@gmail.com> References: <cover-00.30-00000000000-20210614T101920Z-avarab@gmail.com> <cover-00.27-0000000000-20210617T101216Z-avarab@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	Base for "config-based-hooks" \| expand [00/27] Base for "config-based-hooks" [01/27] hook: add 'run' subcommand [02/27] gc: use hook library for pre-auto-gc hook [03/27] rebase: teach pre-rebase to use hook.h [04/27] am: convert applypatch hooks to use config [05/27] hooks: convert 'post-checkout' hook to hook library [06/27] merge: use config-based hooks for post-merge hook [07/27] git hook run: add an --ignore-missing flag [08/27] send-email: use 'git hook run' for 'sendemail-validate' [09/27] git-p4: use 'git hook' to run hooks [10/27] commit: use hook.h to execute hooks [11/27] read-cache: convert post-index-change hook to use config [12/27] receive-pack: convert push-to-checkout hook to hook.h [13/27] run-command: remove old run_hook_{le,ve}() hook API [14/27] run-command: allow stdin for run_processes_parallel [15/27] hook: support passing stdin to hooks [16/27] am: convert 'post-rewrite' hook to hook.h [17/27] run-command: add stdin callback for parallelization [18/27] hook: provide stdin by string_list or callback [19/27] hook: convert 'post-rewrite' hook in sequencer.c to hook.h [20/27] transport: convert pre-push hook to use config [21/27] reference-transaction: use hook.h to run hooks [22/27] run-command: allow capturing of collated output [23/27] hooks: allow callers to capture output [24/27] receive-pack: convert 'update' hook to hook.h [25/27] post-update: use hook.h library [26/27] receive-pack: convert receive hooks to hook.h [27/27] hooks: fix a TOCTOU in "did we run a hook?" heuristic

Message ID

patch-14.27-477d75bf57-20210617T101217Z-avarab@gmail.com (mailing list archive)

State

New, archived

Headers

From: =?utf-8?b?w4Z2YXIgQXJuZmrDtnLDsCBCamFybWFzb24=?=  <avarab@gmail.com>
To: git@vger.kernel.org
Cc: Junio C Hamano <gitster@pobox.com>,
 Emily Shaffer <emilyshaffer@google.com>, Jeff King <peff@peff.net>,
 Taylor Blau <me@ttaylorr.com>, Felipe Contreras <felipe.contreras@gmail.com>,
 Eric Sunshine <sunshine@sunshineco.com>,
 "brian m . carlson" <sandals@crustytoothpaste.net>,
 Josh Steadmon <steadmon@google.com>, Jonathan Tan <jonathantanmy@google.com>,
 Derrick Stolee <stolee@gmail.com>, =?utf-8?b?w4Z2YXIgQXJuZmrDtnLDsCBCamFy?=
	=?utf-8?b?bWFzb24=?=  <avarab@gmail.com>
Subject: [PATCH 14/27] run-command: allow stdin for run_processes_parallel
Date: Thu, 17 Jun 2021 12:22:48 +0200
Message-Id: <patch-14.27-477d75bf57-20210617T101217Z-avarab@gmail.com>
In-Reply-To: <cover-00.27-0000000000-20210617T101216Z-avarab@gmail.com>
References: <cover-00.30-00000000000-20210614T101920Z-avarab@gmail.com>
 <cover-00.27-0000000000-20210617T101216Z-avarab@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

Series

Base for "config-based-hooks" | expand

Commit Message

Ævar Arnfjörð Bjarmason June 17, 2021, 10:22 a.m. UTC

From: Emily Shaffer <emilyshaffer@google.com>

While it makes sense not to inherit stdin from the parent process to
avoid deadlocking, it's not necessary to completely ban stdin to
children. An informed user should be able to configure stdin safely. By
setting `some_child.process.no_stdin=1` before calling `get_next_task()`
we provide a reasonable default behavior but enable users to set up
stdin streaming for themselves during the callback.

`some_child.process.stdout_to_stderr`, however, remains unmodifiable by
`get_next_task()` - the rest of the run_processes_parallel() API depends
on child output in stderr.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 run-command.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/run-command.c b/run-command.c
index 95c950a4a2..0bf771845e 100644
--- a/run-command.c
+++ b/run-command.c
@@ -1628,6 +1628,14 @@  static int pp_start_one(struct parallel_processes *pp)
 	if (i == pp->max_processes)
 		BUG("bookkeeping is hard");
 
+	/*
+	 * By default, do not inherit stdin from the parent process - otherwise,
+	 * all children would share stdin! Users may overwrite this to provide
+	 * something to the child's stdin by having their 'get_next_task'
+	 * callback assign 0 to .no_stdin and an appropriate integer to .in.
+	 */
+	pp->children[i].process.no_stdin = 1;
+
 	code = pp->get_next_task(&pp->children[i].process,
 				 &pp->children[i].err,
 				 pp->data,
@@ -1639,7 +1647,6 @@  static int pp_start_one(struct parallel_processes *pp)
 	}
 	pp->children[i].process.err = -1;
 	pp->children[i].process.stdout_to_stderr = 1;
-	pp->children[i].process.no_stdin = 1;
 
 	if (start_command(&pp->children[i].process)) {
 		code = pp->start_failure(&pp->children[i].err,

[14/27] run-command: allow stdin for run_processes_parallel

Commit Message

Patch