dbus-launch: has non-obvious critical sections in which an X error would cause process leaks

Submitted by Роман Донченко

Assigned to D-Bus Maintainers

Description

Created attachment 93633 Proposed patch

If an X error occurs before the main dbus-launch process transmits the daemon's PID to the babysitter, x_io_error_handler will try to kill the bus with bus_pid_to_kill still set to -1. This will result in killing every process that dbus-launch can get its hands on.

I can easily reproduce this by running xvfb-run sh -c 'dbus-launch --autolaunch=11111111111111111111111111111111 &' a bunch of times.

The attached patch fixes this by making sure bus_pid_to_kill doesn't try to kill -1. It also fixes a related problem: if the X error happens after the fork but before the babysitter gets the bus PID, the bus won't be killed, because bus_pid_to_kill isn't initialized yet.

~~Patch 93633~~, "Proposed patch":
dont-kill-minus-one.patch

Version: 1.5