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Merge branch 'dbus-1.6'

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Conflicts:
	NEWS
	configure.ac
This commit is contained in:
Simon McVittie 2012-06-15 13:23:13 +01:00
commit 085cabfbf4
3 changed files with 152 additions and 33 deletions
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6
NEWS
View file

@ -1,6 +1,12 @@
D-Bus 1.7.0 (UNRELEASED)
==
Fixes:
• Add dbus-launch --exit-with-x11 option. Distributions should use this
in their X11 session startup infrastructure, in preference to
the --exit-with-session option. (fd.o #39197, Simon McVittie)
D-Bus 1.6.0 (2012-06-05)
==

88
doc/dbus-launch.1
View file

@ -7,7 +7,7 @@
dbus\-launch \- Utility to start a message bus from a shell script
.SH SYNOPSIS
.PP
.B dbus\-launch [\-\-version] [\-\-sh\-syntax] [\-\-csh\-syntax] [\-\-auto\-syntax] [\-\-exit\-with\-session] [\-\-autolaunch=MACHINEID] [\-\-config\-file=FILENAME] [PROGRAM] [ARGS...]
.B dbus\-launch [\-\-version] [\-\-sh\-syntax] [\-\-csh\-syntax] [\-\-auto\-syntax] [\-\-exit\-with\-session] [\-\-exit\-with\-x11] [\-\-autolaunch=MACHINEID] [\-\-config\-file=FILENAME] [PROGRAM] [ARGS...]
.SH DESCRIPTION
@ -51,30 +51,45 @@ know which shell your script is written in.
See http://www.freedesktop.org/software/dbus/ for more information
about D\-Bus. See also the man page for \fIdbus\-daemon\fP.
.PP
Here is an example of how to use \fIdbus\-launch\fP with an
sh\-compatible shell to start the per\-session bus daemon:
.nf
.SH EXAMPLES
Distributions running
.B dbus\-launch
as part of a standard X session should run
.B "dbus\-launch \-\-exit\-with\-x11"
after the X server has started and become available, as a wrapper around
the "main" X client (typically a session manager or window manager), as in
these examples:
.RS
.B "dbus\-launch \-\-exit\-with\-x11 gnome\-session"
.B "dbus\-launch \-\-exit\-with\-x11 openbox"
.B "dbus\-launch \-\-exit\-with\-x11 ~/.xsession"
.RE
If your distribution does not do this, you can achieve similar results
by running your session or window manager in the same way in a script
run by your X session, such as
.BR ~/.xsession ,
.B ~/.xinitrc
or
.BR ~/.Xclients .
To start a D-Bus session within a text-mode session, you can run
dbus-launch in the background. For instance, in a sh-compatible shell:
.nf
## test for an existing bus daemon, just to be safe
if test \-z "$DBUS_SESSION_BUS_ADDRESS" ; then
## if not found, launch a new one
eval `dbus\-launch \-\-sh\-syntax \-\-exit\-with\-session`
eval `dbus\-launch \-\-sh\-syntax`
echo "D\-Bus per\-session daemon address is: $DBUS_SESSION_BUS_ADDRESS"
fi
.fi
You might run something like that in your login scripts.
.PP
Another way to use \fIdbus\-launch\fP is to run your main session
program, like so:
.nf
dbus\-launch gnome\-session
.fi
The above would likely be appropriate for ~/.xsession or ~/.Xclients.
Note that in this case, dbus-launch will exit, and dbus-daemon will not be
terminated automatically on logout.
.SH AUTOMATIC LAUNCHING
@ -152,11 +167,25 @@ the \-\-session argument. See the man page for dbus\-daemon
Emit csh compatible code to set up environment variables.
.TP
.I "\-\-exit\-with\-session"
If this option is provided, a persistent "babysitter" process will be
created that watches stdin for HUP and tries to connect to the X
server. If this process gets a HUP on stdin or loses its X connection,
it kills the message bus daemon.
.I \-\-exit\-with\-x11
If this option is provided, a persistent "babysitter" process will be
created, and will connect to the X server. If it cannot do so, launching
fails. If the "babysitter" process loses its X connection,
it kills the message bus daemon, disconnecting all of its clients (which
should exit in response). This avoids having leftover daemon
processes from a user X session, after the X session has ended.
.TP
.I \-\-exit\-with\-session
If this option is provided, a persistent "babysitter" process will be
created, as if for
.BR \-\-exit\-with\-x11 .
If it cannot connect to the X server, it will monitor the terminal from which
.B dbus-launch
was started instead, and if it gets a HUP on stdin, the message bus daemon
will be killed. This option is not recommended, since it will consume input
from the terminal where it was started; it is mainly provided for
backwards compatibility.
.TP
.I "\-\-autolaunch=MACHINEID"
@ -175,6 +204,19 @@ Emit Bourne\-shell compatible code to set up environment variables.
.I "\-\-version"
Print the version of dbus\-launch
.SH NOTES
If you run
.B "dbus\-launch myapp"
(with any other options), dbus\-daemon will
.I not
exit when
.B myapp
terminates: this is because
.B myapp
is assumed to be part of a larger session, rather than a session in its
own right.
.SH AUTHOR
See http://www.freedesktop.org/software/dbus/doc/AUTHORS

91
tools/dbus-launch.c
View file

@ -43,6 +43,47 @@
extern Display *xdisplay;
#endif
/* PROCESSES
*
* If you are in a shell and run "dbus-launch myapp", here is what happens:
*
* shell [*]
* \- main() --exec--> myapp[*]
* \- "intermediate parent"
* \- bus-runner --exec--> dbus-daemon --fork
* \- babysitter[*] \- final dbus-daemon[*]
*
* Processes marked [*] survive the initial flurry of activity.
*
* If you run "dbus-launch --sh-syntax" then the diagram is the same, except
* that main() prints variables and exits 0 instead of exec'ing myapp.
*
* PIPES
*
* dbus-daemon --print-pid -> bus_pid_to_launcher_pipe -> main
* dbus-daemon --print-address -> bus_address_to_launcher_pipe -> main
* main -> bus_pid_to_babysitter_pipe -> babysitter
*
* The intermediate parent looks pretty useless at first glance. Its purpose
* is to avoid the bus-runner becoming a zombie: when the intermediate parent
* terminates, the bus-runner and babysitter are reparented to init, which
* reaps them if they have finished. We can't rely on main() to reap arbitrary
* children because it might exec myapp, after which it can't be relied on to
* reap its children. We *can* rely on main() to reap the intermediate parent,
* because that happens before it execs myapp.
*
* It's unclear why dbus-daemon needs to fork, but we explicitly tell it to
* for some reason, then wait for it. If we left it undefined, a forking
* dbus-daemon would get the parent process reparented to init and reaped
* when the intermediate parent terminated, and a non-forking dbus-daemon
* would get reparented to init and carry on there.
*
* myapp is exec'd by the process that initially ran main() so that it's
* the shell's child, so the shell knows how to do job control and stuff.
* This is desirable for the "dbus-launch an application" use-case, less so
* for the "dbus-launch a test suite in an isolated session" use-case.
*/
static char* machine_uuid = NULL;
const char*
@ -140,7 +181,7 @@ verbose (const char *format,
static void
usage (int ecode)
{
fprintf (stderr, "dbus-launch [--version] [--help] [--sh-syntax] [--csh-syntax] [--auto-syntax] [--exit-with-session]\n");
fprintf (stderr, "dbus-launch [--version] [--help] [--sh-syntax] [--csh-syntax] [--auto-syntax] [--exit-with-session] [--exit-with-x11]\n");
exit (ecode);
}
@ -451,11 +492,20 @@ kill_bus_when_session_ends (void)
else
tty_fd = -1;
if (tty_fd >= 0)
verbose ("stdin isatty(), monitoring it\n");
if (x_fd >= 0)
{
verbose ("session lifetime is defined by X, not monitoring stdin\n");
tty_fd = -1;
}
else if (tty_fd >= 0)
{
verbose ("stdin isatty(), monitoring it\n");
}
else
verbose ("stdin was not a TTY, not monitoring it\n");
{
verbose ("stdin was not a TTY, not monitoring it\n");
}
if (tty_fd < 0 && x_fd < 0)
{
fprintf (stderr, "No terminal on standard input and no X display; cannot attach message bus to session lifetime\n");
@ -759,6 +809,7 @@ main (int argc, char **argv)
const char *runprog = NULL;
int remaining_args = 0;
int exit_with_session;
int exit_with_x11 = FALSE;
int binary_syntax = FALSE;
int c_shell_syntax = FALSE;
int bourne_shell_syntax = FALSE;
@ -800,6 +851,8 @@ main (int argc, char **argv)
version ();
else if (strcmp (arg, "--exit-with-session") == 0)
exit_with_session = TRUE;
else if (strcmp (arg, "--exit-with-x11") == 0)
exit_with_x11 = TRUE;
else if (strcmp (arg, "--close-stderr") == 0)
close_stderr = TRUE;
else if (strstr (arg, "--autolaunch=") == arg)
@ -911,6 +964,9 @@ main (int argc, char **argv)
if (exit_with_session)
verbose ("--exit-with-session enabled\n");
if (exit_with_x11)
verbose ("--exit-with-x11 enabled\n");
if (autolaunch)
{
#ifndef DBUS_BUILD_X11
@ -933,10 +989,10 @@ main (int argc, char **argv)
}
verbose ("Autolaunch enabled (using X11).\n");
if (!exit_with_session)
if (!exit_with_x11)
{
verbose ("--exit-with-session automatically enabled\n");
exit_with_session = TRUE;
verbose ("--exit-with-x11 automatically enabled\n");
exit_with_x11 = TRUE;
}
if (!x11_init ())
@ -959,12 +1015,27 @@ main (int argc, char **argv)
exit (0);
}
#endif /* DBUS_ENABLE_X11_AUTOLAUNCH */
#endif /* DBUS_BUILD_X11 */
}
else if (exit_with_x11)
{
#ifndef DBUS_BUILD_X11
fprintf (stderr, "Session lifetime based on X11 requested, but X11 support not compiled in.\n");
exit (1);
#else /* DBUS_BUILD_X11 */
if (!x11_init ())
{
fprintf (stderr, "Session lifetime based on X11 requested, but X11 initialization failed.\n");
exit (1);
}
#endif /* DBUS_BUILD_X11 */
}
#ifdef DBUS_BUILD_X11
else if (read_machine_uuid_if_needed())
{
x11_init();
#endif /* DBUS_BUILD_X11 */
}
#endif /* DBUS_BUILD_X11 */
if (pipe (bus_pid_to_launcher_pipe) < 0 ||
@ -1026,7 +1097,7 @@ main (int argc, char **argv)
* and will also reap the pre-forked bus
* daemon
*/
babysit (exit_with_session, ret,
babysit (exit_with_session || exit_with_x11, ret,
bus_pid_to_babysitter_pipe[READ_END]);
exit (0);
}