[PATCH 11 of 12] xenpaging: add watch thread to catch guest shutdown

[Olaf Hering <olaf@aepfle.de>]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1307437221 -7200
# Node ID 9484d35ec6e802aa3727cb6332e649b41e80a615
# Parent  fb445bd61233844f4b9d42b6eca172670f75eb98
xenpaging: add watch thread to catch guest shutdown

If xenpaging is started manually then no event is sent to xenpaging when
the guest is shutdown or rebooted.  Add a watch on the shutdown node to
leave the loop and gracefully shutdown the pager.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/Makefile
--- a/tools/xenpaging/Makefile	Tue Jun 07 11:00:20 2011 +0200
+++ b/tools/xenpaging/Makefile	Tue Jun 07 11:00:21 2011 +0200
@@ -8,6 +8,7 @@ POLICY    = default
 
 SRC      :=
 SRCS     += file_ops.c xc.c xenpaging.c policy_$(POLICY).c
+SRCS     += watch.c
 
 CFLAGS   += -Werror
 CFLAGS   += -Wno-unused
diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/watch.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/xenpaging/watch.c	Tue Jun 07 11:00:21 2011 +0200
@@ -0,0 +1,79 @@
+/* watch for guest shutdown in case xenpaging is started manually */
+#include <unistd.h>
+#include <pthread.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <xs.h>
+#include <xen/xen.h>
+
+struct watch_args {
+    domid_t domain_id;
+    void (*fn)(void);
+};
+
+static pthread_t watch_thread;
+static struct watch_args watch_args;
+static const char shutdown[] = "/control/shutdown";
+
+static void *watch_domain(void *arg)
+{
+    struct watch_args *wa = arg;
+    struct xs_handle *xs;
+    char *dom_path, *path, **vec;
+    unsigned int num;
+    size_t malloc_len;
+    bool ret;
+
+    xs = xs_daemon_open_readonly();
+    if ( xs == NULL )
+        goto exit;
+
+    dom_path = xs_get_domain_path(xs, wa->domain_id);
+    if ( dom_path == NULL )
+        goto close_exit;
+
+    malloc_len = strlen(dom_path) + strlen(shutdown) + 1;
+    path = malloc(malloc_len);
+    if ( path == NULL )
+        goto close_exit;
+
+    snprintf(path, malloc_len, "%s%s", dom_path, shutdown);
+
+    ret = xs_watch(xs, path, "");
+    if ( ret == true )
+    {
+        /* first watch fires right away */
+        vec = xs_read_watch(xs, &num);
+        free(vec);
+        /* wait for real event */
+        vec = xs_read_watch(xs, &num);
+        free(vec);
+        xs_unwatch(xs, path, "");
+    
+        /* notify pager */
+        wa->fn();
+    }
+
+    free(path);
+close_exit:
+    xs_daemon_close(xs);
+exit:
+    pthread_exit(NULL);
+}
+
+void create_watch_thread(domid_t domain_id, void (*fn)(void))
+{
+    watch_args.domain_id = domain_id;
+    watch_args.fn = fn;
+    pthread_create(&watch_thread, NULL, watch_domain, &watch_args);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End: 
+ */
diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/xenpaging.c
--- a/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:20 2011 +0200
+++ b/tools/xenpaging/xenpaging.c	Tue Jun 07 11:00:21 2011 +0200
@@ -57,6 +57,11 @@ static void close_handler(int sig)
     unlink_pagefile();
 }
 
+static void set_interrupted_quit(void)
+{
+    interrupted = SIGQUIT;
+}
+
 static void *init_page(void)
 {
     void *buffer;
@@ -577,6 +582,9 @@ int main(int argc, char *argv[])
     sigaction(SIGINT,  &act, NULL);
     sigaction(SIGALRM, &act, NULL);
 
+    /* watch for shutdown of domain_id */
+    create_watch_thread(paging->mem_event.domain_id, set_interrupted_quit);
+
     /* Evict pages */
     for ( i = 0; i < paging->num_pages; i++ )
     {
diff -r fb445bd61233 -r 9484d35ec6e8 tools/xenpaging/xenpaging.h
--- a/tools/xenpaging/xenpaging.h	Tue Jun 07 11:00:20 2011 +0200
+++ b/tools/xenpaging/xenpaging.h	Tue Jun 07 11:00:21 2011 +0200
@@ -55,6 +55,7 @@ typedef struct xenpaging_victim {
     unsigned long gfn;
 } xenpaging_victim_t;
 
+extern void create_watch_thread(domid_t domain_id, void (*fn)(void));
 
 #endif // __XEN_PAGING_H__