Re: [PATCH] run-command: do not pass child process data into callbacks

From: Johannes Sixt <j6t@kdbg.org>
Date: Mar 1, 2016, 07:13 UTC
Message-ID: <56D54129.4090007@kdbg.org>
In-Reply-To: <1456783026-3328-1-git-send-email-sbeller@google.com>

Am 29.02.2016 um 22:57 schrieb Stefan Beller:

Show 8 quoted lines

> The expected way to pass data into the callback is to pass them via
> the customizable callback pointer. The error reporting in
> default_{start_failure, task_finished} is not user friendly enough, that
> we want to encourage using the child data for such purposes.
> 
> Furthermore the struct child data is cleaned by the run-command API,
> before we access them in the callbacks, leading to use-after-free
> situations.

Thanks. The code changes match what I had prototyped. But please squash in this documentation change:

diff --git a/run-command.h b/run-command.h
index c6a3e42..3d1e59e 100644
--- a/run-command.h
+++ b/run-command.h
@@ -191,9 +191,8 @@ typedef int (*task_finished_fn)(int result,
  * (both stdout and stderr) is routed to stderr in a manner that output
  * from different tasks does not interleave.
  *
- * If start_failure_fn or task_finished_fn are NULL, default handlers
- * will be used. The default handlers will print an error message on
- * error without issuing an emergency stop.
+ * start_failure_fn and task_finished_fn can be NULL to omit any
+ * special handling.
  */
 int run_processes_parallel(int n,
 			   get_next_task_fn,