Attachment 74836 Details for Bug 60859 – dbus-spawn: draw a diagram

[patch] dbus-spawn: draw a diagram

0002-dbus-spawn-draw-a-diagram.patch (text/plain), 2.18 KB, created by Simon McVittie on 2013-02-14 19:24:44 UTC

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Creator: Simon McVittie

Created: 2013-02-14 19:24:44 UTC

Size: 2.18 KB

patch

obsolete

>From 94b917fd3ae16a7c4a4f52036723768a6ebf8d7d Mon Sep 17 00:00:00 2001
>From: Simon McVittie <simon.mcvittie@collabora.co.uk>
>Date: Mon, 3 Dec 2012 17:38:36 +0000
>Subject: [PATCH 2/6] dbus-spawn: draw a diagram
>
>There are enough pipes, fds and processes here that it's important to
>keep track of them.
>---
> dbus/dbus-spawn.c |   30 ++++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
>diff --git a/dbus/dbus-spawn.c b/dbus/dbus-spawn.c
>index 5431602..96cd039 100644
>--- a/dbus/dbus-spawn.c
>+++ b/dbus/dbus-spawn.c
>@@ -174,6 +174,36 @@ read_pid (int        fd,
>  * and the grandchild. The grandchild is our spawned process. The intermediate
>  * child is a babysitter process; it keeps track of when the grandchild
>  * exits/crashes, and reaps the grandchild.
>+ *
>+ * We automatically reap the babysitter process, killing it if necessary,
>+ * when the DBusBabysitter's refcount goes to zero.
>+ *
>+ * Processes:
>+ *
>+ * main process
>+ * | fork() A
>+ * \- babysitter
>+ *    | fork () B
>+ *    \- grandchild     --> exec -->    spawned process
>+ *
>+ * IPC:
>+ *
>+ *          main process  |       babysitter     |  grandchild
>+ *  ======================|======================|================|
>+ *  |          child_err_report_pipe (genuinely a pipe)           |
>+ *  |[READ_END]-------------<<------------------------[WRITE_END] |
>+ *  |        << on failure: CHILD_EXEC_FAILED, errno              |
>+ *  |        << on success: nothing               |               |
>+ *  (error_pipe_from_child)|                      | (child_err_report_fd)
>+ *  |                      |                      |               |
>+ *  |  babysitter_pipe (misnamed, really a socketpair)            |
>+ *  |[0]------------------<->------------[1]      |               |
>+ *  |   << on fork() B failure: CHILD_FORK_FAILED, errno          |
>+ *  |   << on success: CHILD_PID, grandchild's pid|               |
>+ *  |   << on SIGCHLD: CHILD_EXITED, status       |               |
>+ *  |   >> HUP or ERR when main process exits     |               |
>+ *  |(socket_to_babysitter)|        (parent_pipe) |               |
>+ *  |======================|======================|===============|
>  */
> 
> /* Messages from children to parents */
>-- 
>1.7.10.4
>

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Attachments on bug 60859: 74834 | 74835 | 74836 | 74837 | 74838 | 74839 | 74840 | 88459 | 88460 | 88461

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