>From ba1a38092c3b79c5c4668c159a7a1640c6d94c51 Mon Sep 17 00:00:00 2001
From: Sergiu Ivanov <unlimitedscol...@gmail.com>
Date: Tue, 14 Jul 2009 19:41:41 +0000
Subject: [PATCH 2/4] Go away when the mountee has been shut down.
* mount.c (mountee_control): New variable.
(mountee_listen_port): Likewise.
(start_mountee): Store the control port of the mountee in
mountee_control.
(mountee_server): New function.
(_mountee_listen_thread_proc): Likewise.
(setup_unionmount): Request to be notified when the mountee goes
away. Detach a separate thread to wait for the notification.
* mount.h (mountee_control): New variable.
---
mount.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
mount.h | 1 +
2 files changed, 65 insertions(+), 0 deletions(-)
diff --git a/mount.c b/mount.c
index 4d12cd6..26cbd9f 100644
--- a/mount.c
+++ b/mount.c
@@ -24,6 +24,7 @@
#include <hurd/fsys.h>
#include <fcntl.h>
+#include <cthreads.h>
#include "mount.h"
#include "lib.h"
@@ -37,6 +38,7 @@ size_t mountee_argz_len;
node_t * unionmount_proxy;
mach_port_t mountee_port;
+mach_port_t mountee_control = MACH_PORT_NULL;
int mountee_started = 0;
@@ -44,6 +46,10 @@ int mountee_started = 0;
operates (transparent/non-transparent). */
int transparent_mount = 1;
+/* The port for receiving the notification about the shutdown of the
+ mountee. */
+mach_port_t mountee_listen_port;
+
/* Starts the mountee (given by `argz` and `argz_len`), sets it on
node `np` and opens a port `port` to with `flags`. `port` is not
modified when an error occurs. */
@@ -176,10 +182,35 @@ start_mountee (node_t * np, char * argz, size_t argz_len,
int flags,
}
*port = res_port;
+ mountee_control = control;
return 0;
} /* start_mountee */
+/* Listens to the MACH_NOTIFY_NO_SENDERS notification for the port to
+ the root of the mountee. */
+error_t
+mountee_server (mach_msg_header_t * inp, mach_msg_header_t * outp)
+{
+ if (inp->msgh_id == MACH_NOTIFY_DEAD_NAME)
+ {
+ /* Terminate operations conducted by unionfs and shut down. */
+ netfs_shutdown (FSYS_GOAWAY_FORCE);
+ exit (0);
+ }
+
+ return 1;
+} /* mountee_server */
+
+/* The main proc of thread for listening for the MACH_NOTIFY_DEAD_NAME
+ notification on the control port of the mountee. */
+static void
+_mountee_listen_thread_proc (any_t * arg)
+{
+ while (1)
+ mach_msg_server (mountee_server, 0, mountee_listen_port);
+} /* _mountee_listen_thread */
+
/* Sets up a proxy node, sets the translator on it, and registers the
filesystem published by the translator in the list of merged
filesystems. */
@@ -214,6 +245,39 @@ setup_unionmount (void)
mountee_started = 1;
+ /* The previously registered send-once right (used to hold the value
+ returned from mach_port_request_notification) */
+ mach_port_t prev;
+
+ /* Setup the port for receiving notifications. */
+ err = mach_port_allocate (mach_task_self (), MACH_PORT_RIGHT_RECEIVE,
+ &mountee_listen_port);
+ if (err)
+ return err;
+ err = mach_port_insert_right (mach_task_self (), mountee_listen_port,
+ mountee_listen_port, MACH_MSG_TYPE_MAKE_SEND);
+ if (err)
+ {
+ mach_port_deallocate (mach_task_self (), mountee_listen_port);
+ return err;
+ }
+
+ /* Request to be notified when the mountee goes away and
+ `mountee_control` becomes a dead name. */
+ err = mach_port_request_notification (mach_task_self (), mountee_control,
+ MACH_NOTIFY_DEAD_NAME, 1,
mountee_listen_port,
+ MACH_MSG_TYPE_MAKE_SEND_ONCE, &prev);
+ if (prev != MACH_PORT_NULL)
+ mach_port_deallocate (mach_task_self(), prev);
+ if(err)
+ {
+ mach_port_deallocate (mach_task_self(), mountee_listen_port);
+ return err;
+ }
+
+ /* Create a new thread for listening to the notification. */
+ cthread_detach (cthread_fork ((cthread_fn_t) _mountee_listen_thread_proc,
NULL));
+
return err;
} /* setup_unionmount */
diff --git a/mount.h b/mount.h
index d01b234..fd8408b 100644
--- a/mount.h
+++ b/mount.h
@@ -37,6 +37,7 @@ extern size_t mountee_argz_len;
extern node_t * unionmount_proxy;
extern mach_port_t mountee_port;
+extern mach_port_t mountee_control;
extern int mountee_started;
--
1.6.3.3
