Support domain lifecycle events for Xen (Ben Guthro & Daniel Berrange)

ChangeLog

+Tue Nov 25 10:43:40 GMT 2008 Daniel P. Berrange <berrange@redhat.com>
+
+	Xen domain lifecycle events (Ben Guthro & Daniel Berrange)
+	* configure.in: Probe for inotify availability
+	* examples/domain-events/events-c/event-test.c: Default to NULL
+	connection URI to allow probing
+	* include/libvirt/virterror.h, src/virterror.c: Add error code
+	for xen inotify driver
+	* po/POTFILES.in: Add xen_inotify.c
+	* python/libvir.c: Add bogus const cast for python2.4 brokeness
+	* src/Makefile.am: Add xen_inotify.c
+	* src/util.c: Fix file descriptor leak in virRun
+	* src/xen_inotify.c, src/xen_inotify.h: Monitor /etc/xen and
+	/var/lib/xen/domains for new/old configs
+	* src/xen_unified.c, src/xen_unified.h: Wire in inotify driver
+	for events
+	* src/xm_internal.c, src/xm_internal.h: Refactor to allow inotify
+	monitoring of config files
+	* src/xs_internal.c, src/xs_internal.h: Use xenstore watch to
+	check for domain start/destroy events
+
 Tue Nov 25 10:36:40 GMT 2008 Daniel P. Berrange <berrange@redhat.com>
 
 	* src/node_device_conf.c, src/node_device_conf.h,

configure.in

@@ -147,6 +147,8 @@ fi
 dnl Allow to build without Xen, QEMU/KVM, test or remote driver
 AC_ARG_WITH([xen],
 [  --with-xen              add XEN support (on)],[],[with_xen=yes])
+AC_ARG_WITH([xen-inotify],
+[  --with-xen-inotify      add XEN inotify support (on)],[],[with_xen_inotify=yes])
 AC_ARG_WITH([qemu],
 [  --with-qemu             add QEMU/KVM support (on)],[],[with_qemu=yes])
 AC_ARG_WITH([uml],
@@ -334,6 +336,20 @@ AM_CONDITIONAL([WITH_XEN], [test "$with_xen" = "yes"])
 AC_SUBST([XEN_CFLAGS])
 AC_SUBST([XEN_LIBS])
 
+dnl
+dnl check for kernel headers required by xen_inotify
+dnl
+if test "$with_xen" != "yes"; then
+    with_xen_inotify=no
+fi
+if test "$with_xen_inotify" != "no"; then
+    AC_CHECK_HEADER([linux/inotify.h],[],[with_xen_inotify=no])
+fi
+if test "$with_xen_inotify" = "yes"; then
+    AC_DEFINE_UNQUOTED([WITH_XEN_INOTIFY], 1,[whether Xen inotify sub-driver is enabled])
+fi
+AM_CONDITIONAL([WITH_XEN_INOTIFY], [test "$with_xen_inotify" = "yes"])
+
 dnl
 dnl check for kernel headers required by src/bridge.c
 dnl

examples/domain-events/events-c/event-test.c

@@ -308,7 +308,7 @@ int main(int argc, char **argv)
                           myEventRemoveTimeoutFunc);
 
     virConnectPtr dconn = NULL;
-    dconn = virConnectOpen (argv[1] ? argv[1] : "qemu:///system");
+    dconn = virConnectOpen (argv[1] ? argv[1] : NULL);
     if (!dconn) {
         printf("error opening\n");
         return -1;

include/libvirt/virterror.h

@@ -60,6 +60,7 @@ typedef enum {
     VIR_FROM_DOMAIN,    /* Error from domain config */
     VIR_FROM_UML,       /* Error at the UML driver */
     VIR_FROM_NODEDEV, /* Error from node device monitor */
+    VIR_FROM_XEN_INOTIFY, /* Error from xen inotify layer */
 } virErrorDomain;
 
 

po/POTFILES.in

@@ -35,6 +35,7 @@ src/util.c
 src/uuid.c
 src/virsh.c
 src/virterror.c
+src/xen_inotify.c
 src/xen_internal.c
 src/xend_internal.c
 src/xm_internal.c

python/libvir.c

@@ -1577,7 +1577,8 @@ getLibvirtModuleObject (void) {
         return libvirt_module;
 
     // PyImport_ImportModule returns a new reference
-    libvirt_module = PyImport_ImportModule("libvirt");
+    /* Bogus (char *) cast for RHEL-5 python API brokenness */
+    libvirt_module = PyImport_ImportModule((char *)"libvirt");
     if(!libvirt_module) {
 #if DEBUG_ERROR
         printf("%s Error importing libvirt module\n", __FUNCTION__);

src/Makefile.am

@@ -101,6 +101,9 @@ XEN_DRIVER_SOURCES =						\
 		xend_internal.c xend_internal.h			\
 		xm_internal.c xm_internal.h			\
 		xs_internal.c xs_internal.h
+if WITH_XEN_INOTIFY
+XEN_DRIVER_SOURCES += xen_inotify.c xen_inotify.h
+endif
 
 LXC_DRIVER_SOURCES =						\
 		lxc_conf.c lxc_conf.h				\
@@ -189,6 +192,8 @@ libvirt_driver_la_SOURCES =					\
 libvirt_driver_la_CFLAGS = $(XEN_CFLAGS)
 libvirt_driver_la_LDFLAGS = $(XEN_LIBS)
 
+libvirt_driver_la_CFLAGS = $(XEN_CFLAGS)
+
 if WITH_TEST
 if WITH_DRIVER_MODULES
 mod_LTLIBRARIES += libvirt_driver_test.la

src/util.c

@@ -613,6 +613,10 @@ virRun(virConnectPtr conn,
     VIR_FREE(outbuf);
     VIR_FREE(errbuf);
     VIR_FREE(argv_str);
+    if (outfd != -1)
+        close(outfd);
+    if (errfd != -1)
+        close(errfd);
     return ret;
 }
 

src/virterror.c

@@ -262,6 +262,9 @@ virDefaultErrorFunc(virErrorPtr err)
         case VIR_FROM_XENSTORE:
             dom = "Xen Store ";
             break;
+        case VIR_FROM_XEN_INOTIFY:
+            dom = "Xen Inotify ";
+            break;
         case VIR_FROM_DOM:
             dom = "Domain ";
             break;

src/xen_inotify.c

+/*
+ * xen_inofify.c: Xen notification of xml file activity in the
+ *                following dirs:
+ *                /etc/xen
+ *                /var/lib/xend/domains
+ *
+ * Copyright (C) 2008 VirtualIron
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+ *
+ * Author: Ben Guthro
+ */
+#include <config.h>
+#include <dirent.h>
+#include <sys/inotify.h>
+
+#include "virterror_internal.h"
+#include "datatypes.h"
+#include "driver.h"
+#include "memory.h"
+#include "event.h"
+#include "xen_unified.h"
+#include "conf.h"
+#include "domain_conf.h"
+#include "xen_inotify.h"
+#include "xend_internal.h"
+#include "logging.h"
+#include "uuid.h"
+
+#include "xm_internal.h" /* for xenXMDomainConfigParse */
+
+#define virXenInotifyError(conn, code, fmt...)                                 \
+        virReportErrorHelper(NULL, VIR_FROM_XEN_INOTIFY, code, __FILE__,      \
+                               __FUNCTION__, __LINE__, fmt)
+
+#define LIBVIRTD_DOMAINS_DIR "/var/lib/xend/domains"
+static const char *configDir        = NULL;
+static int  useXenConfigCache = 0;
+static xenUnifiedDomainInfoListPtr configInfoList = NULL;
+
+struct xenUnifiedDriver xenInotifyDriver = {
+    xenInotifyOpen, /* open */
+    xenInotifyClose, /* close */
+    NULL, /* version */
+    NULL, /* hostname */
+    NULL, /* URI */
+    NULL, /* nodeGetInfo */
+    NULL, /* getCapabilities */
+    NULL, /* listDomains */
+    NULL, /* numOfDomains */
+    NULL, /* domainCreateLinux */
+    NULL, /* domainSuspend */
+    NULL, /* domainResume */
+    NULL, /* domainShutdown */
+    NULL, /* domainReboot */
+    NULL, /* domainDestroy */
+    NULL, /* domainGetOSType */
+    NULL, /* domainGetMaxMemory */
+    NULL, /* domainSetMaxMemory */
+    NULL, /* domainSetMemory */
+    NULL, /* domainGetInfo */
+    NULL, /* domainSave */
+    NULL, /* domainRestore */
+    NULL, /* domainCoreDump */
+    NULL, /* domainSetVcpus */
+    NULL, /* domainPinVcpu */
+    NULL, /* domainGetVcpus */
+    NULL, /* domainGetMaxVcpus */
+    NULL, /* listDefinedDomains */
+    NULL, /* numOfDefinedDomains */
+    NULL, /* domainCreate */
+    NULL, /* domainDefineXML */
+    NULL, /* domainUndefine */
+    NULL, /* domainAttachDevice */
+    NULL, /* domainDetachDevice */
+    NULL, /* domainGetAutostart */
+    NULL, /* domainSetAutostart */
+    NULL, /* domainGetSchedulerType */
+    NULL, /* domainGetSchedulerParameters */
+    NULL, /* domainSetSchedulerParameters */
+};
+
+static virDomainPtr
+xenInotifyXenCacheLookup(virConnectPtr conn, const char *filename) {
+    xenXMConfCachePtr entry;
+    virDomainPtr dom;
+
+    if (!(entry = virHashLookup(xenXMGetConfigCache(), filename))) {
+        DEBUG("No config found for %s", filename);
+        return NULL;
+    }
+
+    if(!(dom = virGetDomain(conn, entry->def->name,
+                    (unsigned char*)entry->def->uuid))) {
+        DEBUG0("Error getting dom from def");
+        return NULL;
+    }
+    return dom;
+}
+
+static virDomainPtr
+xenInotifyXendDomainsDirLookup(virConnectPtr conn, const char *filename) {
+    int i;
+    virDomainPtr dom;
+    const char *uuid_str;
+    unsigned char uuid[VIR_UUID_BUFLEN];
+
+    /* xend is managing domains. we will get
+    * a filename in the manner:
+    * /var/lib/xend/domains/<uuid>/
+    */
+    uuid_str = filename + strlen(LIBVIRTD_DOMAINS_DIR) + 1;
+
+    if (virUUIDParse(uuid_str, uuid) < 0) {
+        virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                           "parsing uuid %s", uuid_str);
+        return (NULL);
+    }
+    /* call directly into xend here, as driver may not yet
+       be set during open while we are building our
+       initial list of domains */
+    DEBUG("Looking for dom with uuid: %s", uuid_str);
+    if(!(dom = xenDaemonLookupByUUID(conn, uuid))) {
+        /* If we are here, the domain has gone away.
+           search for, and create a domain from the stored
+           list info */
+        for (i=0; i<configInfoList->count; i++) {
+            if (!memcmp(uuid, configInfoList->doms[i]->uuid, VIR_UUID_BUFLEN)) {
+                if(!(dom = virGetDomain(conn, configInfoList->doms[i]->name,
+                                        configInfoList->doms[i]->uuid))) {
+                    virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                       "finding dom for %s", uuid_str);
+                    return NULL;
+                }
+                DEBUG0("Found dom on list");
+                return dom;
+            }
+        }
+        virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                       "%s", _("finding dom on config list"));
+        return NULL;
+    }
+
+    /* succeeded too find domain by uuid */
+    return dom;
+}
+
+static virDomainPtr
+xenInotifyDomainLookup(virConnectPtr conn, const char *filename) {
+    virDomainPtr dom;
+    virDomainInfo info;
+
+    dom = useXenConfigCache ? xenInotifyXenCacheLookup(conn, filename) :
+                              xenInotifyXendDomainsDirLookup(conn, filename);
+
+    if(dom) {
+        if ( (useXenConfigCache ? xenXMDomainGetInfo(dom, &info) :
+                                  xenDaemonDomainGetInfo(dom, &info)) < 0)
+            dom->id = -1;
+        else
+            dom->id = (info.state == VIR_DOMAIN_SHUTOFF) ? -1 : dom->id;
+        return dom;
+    }
+    return NULL;
+}
+
+static int
+xenInotifyXendDomainsDirRemoveEntry(virConnectPtr conn ATTRIBUTE_UNUSED,
+                                    const char *fname) {
+    const char *uuidstr = fname + strlen(LIBVIRTD_DOMAINS_DIR) + 1;
+    unsigned char uuid[VIR_UUID_BUFLEN];
+    int i;
+
+    if (virUUIDParse(uuidstr, uuid) < 0) {
+        virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                           "parsing uuid %s", uuidstr);
+        return -1;
+    }
+
+    /* match and remove on uuid */
+    for (i=0; i<configInfoList->count; i++) {
+        if (!memcmp(uuid, configInfoList->doms[i]->uuid, VIR_UUID_BUFLEN)) {
+            VIR_FREE(configInfoList->doms[i]->name);
+            VIR_FREE(configInfoList->doms[i]);
+
+            if (i < (configInfoList->count - 1))
+                memmove(configInfoList->doms + i,
+                        configInfoList->doms + i + 1,
+                        sizeof(*(configInfoList->doms)) *
+                                (configInfoList->count - (i + 1)));
+
+            if (VIR_REALLOC_N(configInfoList->doms,
+                              configInfoList->count - 1) < 0) {
+                ; /* Failure to reduce memory allocation isn't fatal */
+            }
+            configInfoList->count--;
+            return 0;
+        }
+    }
+    return -1;
+}
+
+static int
+xenInotifyXendDomainsDirAddEntry(virConnectPtr conn,
+                                 const char *fname) {
+    virDomainPtr dom = xenInotifyDomainLookup(conn, fname);
+    if(!dom) {
+        virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                        "%s", _("Error looking up domain"));
+        return -1;
+    }
+
+    if( xenUnifiedAddDomainInfo(configInfoList,
+                                dom->id, dom->name, dom->uuid) < 0) {
+        virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                        "%s", _("Error adding file to config cache"));
+        virUnrefDomain(dom);
+        return -1;
+    }
+    virUnrefDomain(dom);
+    return 0;
+}
+
+static int
+xenInotifyRemoveDomainConfigInfo(virConnectPtr conn,
+                                 const char *fname) {
+    return useXenConfigCache ? xenXMConfigCacheRemoveFile(conn, fname) :
+                               xenInotifyXendDomainsDirRemoveEntry(conn, fname);
+}
+
+static int
+xenInotifyAddDomainConfigInfo(virConnectPtr conn,
+                              const char *fname) {
+    return useXenConfigCache ? xenXMConfigCacheAddFile(conn, fname) :
+                               xenInotifyXendDomainsDirAddEntry(conn, fname);
+}
+
+static void
+xenInotifyEvent(int watch ATTRIBUTE_UNUSED,
+                int fd,
+                int events ATTRIBUTE_UNUSED,
+                void *data)
+{
+    char buf[1024];
+    char fname[1024];
+    struct inotify_event *e;
+    int got;
+    char *tmp, *name;
+    virConnectPtr conn = (virConnectPtr) data;
+    xenUnifiedPrivatePtr priv = NULL;
+    virDomainPtr dom = NULL;
+
+    DEBUG0("got inotify event");
+
+    if( conn && conn->privateData ) {
+        priv = conn->privateData;
+    } else {
+        virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                           "%s", _("conn, or private data is NULL"));
+        return;
+    }
+
+reread:
+    got = read(fd, buf, sizeof(buf));
+    if (got == -1) {
+        if (errno == EINTR)
+            goto reread;
+        return;
+    }
+
+    tmp = buf;
+    while (got) {
+        if (got < sizeof(struct inotify_event))
+            return; /* bad */
+
+        e = (struct inotify_event *)tmp;
+        tmp += sizeof(struct inotify_event);
+        got -= sizeof(struct inotify_event);
+
+        if (got < e->len)
+            return;
+
+        tmp += e->len;
+        got -= e->len;
+
+        name = (char *)&(e->name);
+
+        snprintf(fname, 1024, "%s/%s", configDir, name);
+
+        if (e->mask & (IN_DELETE | IN_MOVED_FROM)) {
+            if (!(dom = xenInotifyDomainLookup(conn, fname))) {
+                virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                           "%s", _("looking up dom"));
+                continue;
+            }
+
+            xenUnifiedDomainEventDispatch(conn->privateData, dom,
+                                          VIR_DOMAIN_EVENT_UNDEFINED,
+                                          VIR_DOMAIN_EVENT_UNDEFINED_REMOVED);
+
+
+            if (xenInotifyRemoveDomainConfigInfo(conn, fname) < 0 ) {
+                virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                   "%s", _("Error adding file to config cache"));
+                return;
+            }
+        } else if (e->mask & ( IN_CREATE | IN_CLOSE_WRITE | IN_MOVED_TO) ) {
+            if (xenInotifyAddDomainConfigInfo(conn, fname) < 0 ) {
+                virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                   "%s", _("Error adding file to config cache"));
+                return;
+            }
+
+            if (!(dom = xenInotifyDomainLookup(conn, fname))) {
+                virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                           "%s", _("looking up dom"));
+                continue;
+            }
+
+            xenUnifiedDomainEventDispatch(conn->privateData, dom,
+                                          VIR_DOMAIN_EVENT_DEFINED,
+                                          VIR_DOMAIN_EVENT_DEFINED_ADDED);
+        }
+
+    }
+}
+
+/**
+ * xenInotifyOpen:
+ * @conn: pointer to the connection block
+ * @name: URL for the target, NULL for local
+ * @flags: combination of virDrvOpenFlag(s)
+ *
+ * Connects and starts listening for inotify events
+ *
+ * Returns 0 or -1 in case of error.
+ */
+int
+xenInotifyOpen(virConnectPtr conn ATTRIBUTE_UNUSED,
+             virConnectAuthPtr auth ATTRIBUTE_UNUSED,
+             int flags ATTRIBUTE_UNUSED)
+{
+    DIR *dh;
+    struct dirent *ent;
+    char path[PATH_MAX];
+    xenUnifiedPrivatePtr priv = (xenUnifiedPrivatePtr) conn->privateData;
+
+    if(priv->xendConfigVersion <= 2) {
+        /* /etc/xen */
+        configDir = xenXMGetConfigDir();
+        useXenConfigCache = 1;
+    } else {
+        /* /var/lib/xend/domains/<uuid>/config.sxp */
+        configDir = LIBVIRTD_DOMAINS_DIR;
+        useXenConfigCache = 0;
+
+        if ( VIR_ALLOC(configInfoList ) < 0) {
+            virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                 "%s", _("failed to allocate configInfoList"));
+            return -1;
+        }
+
+        /* populate initial list */
+         if (!(dh = opendir(configDir))) {
+            virXenInotifyError (NULL, VIR_ERR_INTERNAL_ERROR,
+                                 "%s", strerror(errno));
+            return -1;
+        }
+        while ((ent = readdir(dh))) {
+            if (STRPREFIX(ent->d_name, "."))
+                continue;
+
+            /* Build the full file path */
+            if ((strlen(configDir) + 1 + strlen(ent->d_name) + 1) > PATH_MAX)
+                continue;
+            strcpy(path, configDir);
+            strcat(path, "/");
+            strcat(path, ent->d_name);
+
+            if (xenInotifyAddDomainConfigInfo(conn, path) < 0 ) {
+                virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                   "%s", _("Error adding file to config list"));
+                return -1;
+            }
+        }
+
+    }
+
+    if ((priv->inotifyFD = inotify_init()) < 0) {
+        virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                           "%s", _("initializing inotify"));
+        return -1;
+    }
+
+    DEBUG("Adding a watch on %s", configDir);
+    if (inotify_add_watch(priv->inotifyFD,
+                          configDir,
+                          IN_CREATE |
+                          IN_CLOSE_WRITE | IN_DELETE |
+                          IN_MOVED_TO | IN_MOVED_FROM) < 0) {
+        virXenInotifyError(NULL, VIR_ERR_INTERNAL_ERROR,
+                           "adding watch on %s", _(configDir));
+        return -1;
+    }
+
+    DEBUG0("Building initial config cache");
+    if (useXenConfigCache &&
+        xenXMConfigCacheRefresh (conn) < 0) {
+        DEBUG("Failed to enable XM config cache %s", conn->err.message);
+        return -1;
+    }
+
+    DEBUG0("Registering with event loop");
+    /* Add the handle for monitoring */
+    if ((priv->inotifyWatch = virEventAddHandle(priv->inotifyFD, VIR_EVENT_HANDLE_READABLE,
+                                                xenInotifyEvent, conn, NULL)) < 0) {
+        DEBUG0("Failed to add inotify handle, disabling events");
+    }
+
+    conn->refs++;
+    return 0;
+}
+
+/**
+ * xenInotifyClose:
+ * @conn: pointer to the connection block
+ *
+ * Close and stop listening for inotify events
+ *
+ * Returns 0 in case of success or -1 in case of error.
+ */
+int
+xenInotifyClose(virConnectPtr conn)
+{
+    xenUnifiedPrivatePtr priv = (xenUnifiedPrivatePtr) conn->privateData;
+
+    if(configInfoList)
+        xenUnifiedDomainInfoListFree(configInfoList);
+
+    if (priv->inotifyWatch != -1)
+        virEventRemoveHandle(priv->inotifyWatch);
+    close(priv->inotifyFD);
+    virUnrefConnect(conn);
+
+    return 0;
+}

src/xen_inotify.h

+/*
+ * xen_inofify.h: Xen notification of xml files
+ *
+ * Copyright (C) 2008 VirtualIron
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+ *
+ * Author: Ben Guthro
+ */
+#ifndef __VIR_XEN_INOTIFY_H__
+#define __VIR_XEN_INOTIFY_H__
+#include "internal.h"
+extern struct xenUnifiedDriver xenInotifyDriver;
+
+int		xenInotifyOpen		(virConnectPtr conn,
+                                         virConnectAuthPtr auth,
+                                         int flags);
+int		xenInotifyClose		(virConnectPtr conn);
+#endif

src/xen_unified.c

@@ -37,6 +37,9 @@
 #include "xend_internal.h"
 #include "xs_internal.h"
 #include "xm_internal.h"
+#if WITH_XEN_INOTIFY
+#include "xen_inotify.h"
+#endif
 #include "xml.h"
 #include "util.h"
 #include "memory.h"
@@ -57,6 +60,9 @@ static struct xenUnifiedDriver *drivers[XEN_UNIFIED_NR_DRIVERS] = {
     [XEN_UNIFIED_XEND_OFFSET] = &xenDaemonDriver,
     [XEN_UNIFIED_XS_OFFSET] = &xenStoreDriver,
     [XEN_UNIFIED_XM_OFFSET] = &xenXMDriver,
+#if WITH_XEN_INOTIFY
+    [XEN_UNIFIED_INOTIFY_OFFSET] = &xenInotifyDriver,
+#endif
 };
 
 #define xenUnifiedError(conn, code, fmt...)                                  \
@@ -223,6 +229,7 @@ xenUnifiedOpen (virConnectPtr conn, virConnectAuthPtr auth, int flags)
 {
     int i, ret = VIR_DRV_OPEN_DECLINED;
     xenUnifiedPrivatePtr priv;
+    virDomainEventCallbackListPtr cbList;
 
     if (conn->uri == NULL) {
         if (!xenUnifiedProbe())
@@ -260,6 +267,13 @@ xenUnifiedOpen (virConnectPtr conn, virConnectAuthPtr auth, int flags)
     }
     conn->privateData = priv;
 
+    /* Allocate callback list */
+    if (VIR_ALLOC(cbList) < 0) {
+        xenUnifiedError (NULL, VIR_ERR_NO_MEMORY, "allocating callback list");
+        return VIR_DRV_OPEN_ERROR;
+    }
+    priv->domainEventCallbacks = cbList;
+
     priv->handle = -1;
     priv->xendConfigVersion = -1;
     priv->type = -1;
@@ -333,6 +347,15 @@ xenUnifiedOpen (virConnectPtr conn, virConnectAuthPtr auth, int flags)
         goto fail;
     }
 
+#if WITH_XEN_INOTIFY
+    DEBUG0("Trying Xen inotify sub-driver");
+    if (drivers[XEN_UNIFIED_INOTIFY_OFFSET]->open(conn, auth, flags) ==
+        VIR_DRV_OPEN_SUCCESS) {
+        DEBUG0("Activated Xen inotify sub-driver");
+        priv->opened[XEN_UNIFIED_INOTIFY_OFFSET] = 1;
+    }
+#endif
+
     return VIR_DRV_OPEN_SUCCESS;
 
 fail:
@@ -357,6 +380,8 @@ xenUnifiedClose (virConnectPtr conn)
     int i;
 
     virCapabilitiesFree(priv->caps);
+    virDomainEventCallbackListFree(priv->domainEventCallbacks);
+
     for (i = 0; i < XEN_UNIFIED_NR_DRIVERS; ++i)
         if (priv->opened[i] && drivers[i]->close)
             (void) drivers[i]->close (conn);
@@ -1292,6 +1317,40 @@ xenUnifiedNodeGetFreeMemory (virConnectPtr conn)
     return(0);
 }
 
+static int
+xenUnifiedDomainEventRegister (virConnectPtr conn,
+                               void *callback,
+                               void *opaque,
+                               void (*freefunc)(void *))
+{
+    GET_PRIVATE (conn);
+    if (priv->xsWatch == -1) {
+        xenUnifiedError (conn, VIR_ERR_NO_SUPPORT, __FUNCTION__);
+        return -1;
+    }
+
+    conn->refs++;
+    return virDomainEventCallbackListAdd(conn, priv->domainEventCallbacks,
+                                         callback, opaque, freefunc);
+}
+
+static int
+xenUnifiedDomainEventDeregister (virConnectPtr conn,
+                                 void *callback)
+{
+    int ret;
+    GET_PRIVATE (conn);
+    if (priv->xsWatch == -1) {
+        xenUnifiedError (conn, VIR_ERR_NO_SUPPORT, __FUNCTION__);
+        return -1;
+    }
+
+    ret = virDomainEventCallbackListRemove(conn, priv->domainEventCallbacks,
+                                            callback);
+    virUnrefConnect(conn);
+    return ret;
+}
+
 /*----- Register with libvirt.c, and initialise Xen drivers. -----*/
 
 #define HV_VERSION ((DOM0_INTERFACE_VERSION >> 24) * 1000000 +         \
@@ -1356,6 +1415,8 @@ static virDriver xenUnifiedDriver = {
     .domainBlockPeek	= xenUnifiedDomainBlockPeek,
     .nodeGetCellsFreeMemory = xenUnifiedNodeGetCellsFreeMemory,
     .getFreeMemory = xenUnifiedNodeGetFreeMemory,
+    .domainEventRegister = xenUnifiedDomainEventRegister,
+    .domainEventDeregister = xenUnifiedDomainEventDeregister,
 };
 
 /**
@@ -1375,3 +1436,139 @@ xenRegister (void)
     return virRegisterDriver (&xenUnifiedDriver);
 }
 
+/**
+ * xenUnifiedDomainInfoListFree:
+ *
+ * Free the Domain Info List
+ */
+void
+xenUnifiedDomainInfoListFree(xenUnifiedDomainInfoListPtr list)
+{
+    int i;
+    for (i=0; i<list->count; i++) {
+        VIR_FREE(list->doms[i]->name);
+        VIR_FREE(list->doms[i]);
+    }
+    VIR_FREE(list);
+}
+
+/**
+ * xenUnifiedAddDomainInfo:
+ *
+ * Add name and uuid to the domain info list
+ *
+ * Returns: 0 on success, -1 on failure
+ */
+int
+xenUnifiedAddDomainInfo(xenUnifiedDomainInfoListPtr list,
+                        int id, char *name,
+                        unsigned char *uuid)
+{
+    xenUnifiedDomainInfoPtr info;
+    int n;
+
+    /* check if we already have this callback on our list */
+    for (n=0; n < list->count; n++) {
+        if (STREQ(list->doms[n]->name, name) &&
+            !memcmp(list->doms[n]->uuid, uuid, VIR_UUID_BUFLEN)) {
+            DEBUG0("WARNING: dom already tracked");
+            return -1;
+        }
+    }
+
+    if (VIR_ALLOC(info) < 0)
+        goto memory_error;
+    if (!(info->name = strdup(name)))
+        goto memory_error;
+
+    memcpy(info->uuid, uuid, VIR_UUID_BUFLEN);
+    info->id = id;
+
+    /* Make space on list */
+    n = list->count;
+    if (VIR_REALLOC_N(list->doms, n + 1) < 0) {
+        goto memory_error;
+    }
+
+    list->doms[n] = info;
+    list->count++;
+    return 0;
+memory_error:
+    xenUnifiedError (NULL, VIR_ERR_NO_MEMORY, "allocating domain info");
+    if (info)
+        VIR_FREE(info->name);
+    VIR_FREE(info);
+    return -1;
+}
+
+/**
+ * xenUnifiedRemoveDomainInfo:
+ *
+ * Removes name and uuid to the domain info list
+ *
+ * Returns: 0 on success, -1 on failure
+ */
+int
+xenUnifiedRemoveDomainInfo(xenUnifiedDomainInfoListPtr list,
+                           int id, char *name,
+                           unsigned char *uuid)
+{
+    int i;
+    for (i = 0 ; i < list->count ; i++) {
+        if( list->doms[i]->id == id &&
+            STREQ(list->doms[i]->name, name) &&
+            !memcmp(list->doms[i]->uuid, uuid, VIR_UUID_BUFLEN)) {
+
+            VIR_FREE(list->doms[i]->name);
+            VIR_FREE(list->doms[i]);
+
+            if (i < (list->count - 1))
+                memmove(list->doms + i,
+                        list->doms + i + 1,
+                        sizeof(*(list->doms)) *
+                                (list->count - (i + 1)));
+
+            if (VIR_REALLOC_N(list->doms,
+                              list->count - 1) < 0) {
+                ; /* Failure to reduce memory allocation isn't fatal */
+            }
+            list->count--;
+
+            return 0;
+        }
+    }
+    return -1;
+}
+
+/**
+ * xenUnifiedDomainEventDispatch:
+ *
+ * Dispatch domain events to registered callbacks
+ *
+ */
+void xenUnifiedDomainEventDispatch (xenUnifiedPrivatePtr priv,
+                                    virDomainPtr dom,
+                                    int event,
+                                    int detail)
+{
+    int i;
+    virDomainEventCallbackListPtr cbList;
+
+    if(!priv) return;
+
+    cbList = priv->domainEventCallbacks;
+    if(!cbList) return;
+
+    for(i=0 ; i < cbList->count ; i++) {
+        if(cbList->callbacks[i] && cbList->callbacks[i]->cb) {
+            if (dom) {
+                DEBUG("Dispatching callback %p %p event %d",
+                        cbList->callbacks[i],
+                        cbList->callbacks[i]->cb, event);
+                cbList->callbacks[i]->cb(cbList->callbacks[i]->conn,
+                                         dom, event, detail,
+                                         cbList->callbacks[i]->opaque);
+            }
+        }
+    }
+}

src/xen_unified.h

@@ -14,6 +14,12 @@
 #include "internal.h"
 #include "capabilities.h"
 #include "driver.h"
+#include "domain_conf.h"
+#include "xs_internal.h"
+#if WITH_XEN_INOTIFY
+#include "xen_inotify.h"
+#endif
+#include "domain_event.h"
 
 #ifndef HAVE_WINSOCK2_H
 #include <sys/un.h>
@@ -29,7 +35,13 @@ extern int xenRegister (void);
 #define XEN_UNIFIED_XEND_OFFSET 2
 #define XEN_UNIFIED_XS_OFFSET 3
 #define XEN_UNIFIED_XM_OFFSET 4
+
+#if WITH_XEN_INOTIFY
+#define XEN_UNIFIED_INOTIFY_OFFSET 5
+#define XEN_UNIFIED_NR_DRIVERS 6
+#else
 #define XEN_UNIFIED_NR_DRIVERS 5
+#endif
 
 #define MIN_XEN_GUEST_SIZE 64  /* 64 megabytes */
 
@@ -85,6 +97,33 @@ struct xenUnifiedDriver {
         virDrvDomainSetSchedulerParameters domainSetSchedulerParameters;
 };
 
+typedef struct xenXMConfCache *xenXMConfCachePtr;
+typedef struct xenXMConfCache {
+    time_t refreshedAt;
+    char filename[PATH_MAX];
+    virDomainDefPtr def;
+} xenXMConfCache;
+
+/* xenUnifiedDomainInfoPtr:
+ * The minimal state we have about active domains
+ * This is the minmal info necessary to still get a
+ * virDomainPtr when the domain goes away
+ */
+struct _xenUnifiedDomainInfo {
+    int  id;
+    char *name;
+    unsigned char uuid[VIR_UUID_BUFLEN];
+};
+typedef struct _xenUnifiedDomainInfo xenUnifiedDomainInfo;
+typedef xenUnifiedDomainInfo *xenUnifiedDomainInfoPtr;
+
+struct _xenUnifiedDomainInfoList {
+    unsigned int count;
+    xenUnifiedDomainInfoPtr *doms;
+};
+typedef struct _xenUnifiedDomainInfoList xenUnifiedDomainInfoList;
+typedef xenUnifiedDomainInfoList *xenUnifiedDomainInfoListPtr;
+
 /* xenUnifiedPrivatePtr:
  *
  * Per-connection private data, stored in conn->privateData.  All Xen
@@ -113,6 +152,19 @@ struct _xenUnifiedPrivate {
      * xen_unified.c.
      */
     int opened[XEN_UNIFIED_NR_DRIVERS];
+
+    /* A list of xenstore watches */
+    xenStoreWatchListPtr xsWatchList;
+    int xsWatch;
+
+    /* An list of callbacks */
+    virDomainEventCallbackListPtr domainEventCallbacks;
+
+#if WITH_XEN_INOTIFY
+    /* The inotify fd */
+    int inotifyFD;
+    int inotifyWatch;
+#endif
 };
 
 typedef struct _xenUnifiedPrivate *xenUnifiedPrivatePtr;
@@ -122,4 +174,15 @@ int xenNbCells(virConnectPtr conn);
 int xenNbCpus(virConnectPtr conn);
 char *xenDomainUsedCpus(virDomainPtr dom);
 
+void xenUnifiedDomainInfoListFree(xenUnifiedDomainInfoListPtr info);
+int  xenUnifiedAddDomainInfo(xenUnifiedDomainInfoListPtr info,
+                             int id, char *name,
+                             unsigned char *uuid);
+int  xenUnifiedRemoveDomainInfo(xenUnifiedDomainInfoListPtr info,
+                                int id, char *name,
+                                unsigned char *uuid);
+void xenUnifiedDomainEventDispatch (xenUnifiedPrivatePtr priv,
+                                    virDomainPtr dom,
+                                    int event,
+                                    int detail);
 #endif /* __VIR_XEN_UNIFIED_H__ */

src/xm_internal.c

@@ -45,6 +45,8 @@
 #include "uuid.h"
 #include "util.h"
 #include "memory.h"
+#include "logging.h"
+
 
 /* The true Xen limit varies but so far is always way
    less than 1024, which is the Linux kernel limit according
@@ -54,13 +56,6 @@
 static int xenXMConfigSetString(virConfPtr conf, const char *setting,
                                 const char *str);
 
-typedef struct xenXMConfCache *xenXMConfCachePtr;
-typedef struct xenXMConfCache {
-    time_t refreshedAt;
-    char filename[PATH_MAX];
-    virDomainDefPtr def;
-} xenXMConfCache;
-
 static char configDir[PATH_MAX];
 /* Config file name to config object */
 static virHashTablePtr configCache = NULL;
@@ -124,6 +119,14 @@ struct xenUnifiedDriver xenXMDriver = {
     NULL, /* domainSetSchedulerParameters */
 };
 
+virHashTablePtr xenXMGetConfigCache (void) {
+    return configCache;
+}
+
+char *xenXMGetConfigDir (void) {
+    return configDir;
+}
+
 #define xenXMError(conn, code, fmt...)                                       \
         virReportErrorHelper(conn, VIR_FROM_XENXM, code, __FILE__,         \
                                __FUNCTION__, __LINE__, fmt)
@@ -371,13 +374,121 @@ xenXMConfigSaveFile(virConnectPtr conn, const char *filename, virDomainDefPtr de
     return ret;
 }
 
+int
+xenXMConfigCacheRemoveFile(virConnectPtr conn ATTRIBUTE_UNUSED,
+                           const char *filename)
+{
+    xenXMConfCachePtr entry;
+
+    entry = virHashLookup(configCache, filename);
+    if (!entry) {
+        DEBUG("No config entry for %s", filename);
+        return 0;
+    }
+
+    virHashRemoveEntry(nameConfigMap, entry->def->name, NULL);
+    virHashRemoveEntry(configCache, filename, xenXMConfigFree);
+    DEBUG("Removed %s %s", entry->def->name, filename);
+    return 0;
+}
+
+
+int
+xenXMConfigCacheAddFile(virConnectPtr conn, const char *filename)
+{
+    xenXMConfCachePtr entry;
+    struct stat st;
+    int newborn = 0;
+    time_t now = time(NULL);
+
+    DEBUG("Adding file %s", filename);
+
+    /* Get modified time */
+    if ((stat(filename, &st) < 0)) {
+        xenXMError (conn, VIR_ERR_INTERNAL_ERROR,
+                    "cannot stat %s: %s", filename, strerror(errno));
+        return -1;
+    }
+
+    /* Ignore zero length files, because inotify fires before
+       any content has actually been created */
+    if (st.st_size == 0) {
+        DEBUG("Ignoring zero length file %s", filename);
+        return -1;
+    }
+
+    /* If we already have a matching entry and it is not
+    modified, then carry on to next one*/
+    if ((entry = virHashLookup(configCache, filename))) {
+        char *nameowner;
+
+        if (entry->refreshedAt >= st.st_mtime) {
+            entry->refreshedAt = now;
+            /* return success if up-to-date */
+            return 0;
+        }
+
+        /* If we currently own the name, then release it and
+            re-acquire it later - just in case it was renamed */
+        nameowner = (char *)virHashLookup(nameConfigMap, entry->def->name);
+        if (nameowner && STREQ(nameowner, filename)) {
+            virHashRemoveEntry(nameConfigMap, entry->def->name, NULL);
+        }
+
+        /* Clear existing config entry which needs refresh */
+        virDomainDefFree(entry->def);
+        entry->def = NULL;
+    } else { /* Completely new entry */
+        newborn = 1;
+        if (VIR_ALLOC(entry) < 0) {
+            xenXMError (conn, VIR_ERR_NO_MEMORY, "%s", strerror(errno));
+            return -1;
+        }
+        memcpy(entry->filename, filename, PATH_MAX);
+    }
+    entry->refreshedAt = now;
+
+    if (!(entry->def = xenXMConfigReadFile(conn, entry->filename))) {
+        DEBUG("Failed to read %s", entry->filename);
+        if (!newborn)
+            virHashRemoveEntry(configCache, filename, NULL);
+        VIR_FREE(entry);
+        return -1;
+    }
+
+    /* If its a completely new entry, it must be stuck into
+        the cache (refresh'd entries are already registered) */
+    if (newborn) {
+        if (virHashAddEntry(configCache, entry->filename, entry) < 0) {
+            virDomainDefFree(entry->def);
+            VIR_FREE(entry);
+            xenXMError (conn, VIR_ERR_INTERNAL_ERROR,
+                        "%s", _("xenXMConfigCacheRefresh: virHashAddEntry"));
+            return -1;
+        }
+    }
+
+    /* See if we need to map this config file in as the primary owner
+        * of the domain in question
+        */
+    if (!virHashLookup(nameConfigMap, entry->def->name)) {
+        if (virHashAddEntry(nameConfigMap, entry->def->name, entry->filename) < 0) {
+            virHashRemoveEntry(configCache, filename, NULL);
+            virDomainDefFree(entry->def);
+            VIR_FREE(entry);
+        }
+    }
+    DEBUG("Added config %s %s", entry->def->name, filename);
+
+    return 0;
+}
 
 /* This method is called by various methods to scan /etc/xen
    (or whatever directory was set by  LIBVIRT_XM_CONFIG_DIR
    environment variable) and process any domain configs. It
    has rate-limited so never rescans more frequently than
    once every X seconds */
-static int xenXMConfigCacheRefresh (virConnectPtr conn) {
+int xenXMConfigCacheRefresh (virConnectPtr conn) {
     DIR *dh;
     struct dirent *ent;
     time_t now = time(NULL);
@@ -401,9 +512,7 @@ static int xenXMConfigCacheRefresh (virConnectPtr conn) {
     }
 
     while ((ent = readdir(dh))) {
-        xenXMConfCachePtr entry;
         struct stat st;
-        int newborn = 0;
         char path[PATH_MAX];
 
         /*
@@ -447,62 +556,8 @@ static int xenXMConfigCacheRefresh (virConnectPtr conn) {
 
         /* If we already have a matching entry and it is not
            modified, then carry on to next one*/
-        if ((entry = virHashLookup(configCache, path))) {
-            char *nameowner;
-
-            if (entry->refreshedAt >= st.st_mtime) {
-                entry->refreshedAt = now;
-                continue;
-            }
-
-            /* If we currently own the name, then release it and
-               re-acquire it later - just in case it was renamed */
-            nameowner = (char *)virHashLookup(nameConfigMap, entry->def->name);
-            if (nameowner && STREQ(nameowner, path)) {
-                virHashRemoveEntry(nameConfigMap, entry->def->name, NULL);
-            }
-
-            /* Clear existing config entry which needs refresh */
-            virDomainDefFree(entry->def);
-            entry->def = NULL;
-        } else { /* Completely new entry */
-            newborn = 1;
-            if (VIR_ALLOC(entry) < 0) {
-                xenXMError (conn, VIR_ERR_NO_MEMORY, "%s", strerror(errno));
-                goto cleanup;
-            }
-            memcpy(entry->filename, path, PATH_MAX);
-        }
-        entry->refreshedAt = now;
-
-        if (!(entry->def = xenXMConfigReadFile(conn, entry->filename))) {
-            if (!newborn)
-                virHashRemoveEntry(configCache, path, NULL);
-            VIR_FREE(entry);
-            continue;
-        }
-
-        /* If its a completely new entry, it must be stuck into
-           the cache (refresh'd entries are already registered) */
-        if (newborn) {
-            if (virHashAddEntry(configCache, entry->filename, entry) < 0) {
-                virDomainDefFree(entry->def);
-                VIR_FREE(entry);
-                xenXMError (conn, VIR_ERR_INTERNAL_ERROR,
-                            "%s", _("xenXMConfigCacheRefresh: virHashAddEntry"));
-                goto cleanup;
-            }
-        }
-
-        /* See if we need to map this config file in as the primary owner
-         * of the domain in question
-         */
-        if (!virHashLookup(nameConfigMap, entry->def->name)) {
-            if (virHashAddEntry(nameConfigMap, entry->def->name, entry->filename) < 0) {
-                virHashRemoveEntry(configCache, ent->d_name, NULL);
-                virDomainDefFree(entry->def);
-                VIR_FREE(entry);
-            }
+        if (xenXMConfigCacheAddFile(conn, path) < 0) {
+            /* Ignoring errors, since alot of stuff goes wrong in /etc/xen */
         }
     }
 
@@ -513,7 +568,6 @@ static int xenXMConfigCacheRefresh (virConnectPtr conn) {
     virHashRemoveSet(configCache, xenXMConfigReaper, xenXMConfigFree, (const void*) &now);
     ret = 0;
 
- cleanup:
     if (dh)
         closedir(dh);
 
@@ -1503,8 +1557,10 @@ virDomainPtr xenXMDomainLookupByName(virConnectPtr conn, const char *domname) {
         return (NULL);
     }
 
+#ifndef WITH_XEN_INOTIFY
     if (xenXMConfigCacheRefresh (conn) < 0)
         return (NULL);
+#endif
 
     if (!(filename = virHashLookup(nameConfigMap, domname)))
         return (NULL);
@@ -1555,8 +1611,10 @@ virDomainPtr xenXMDomainLookupByUUID(virConnectPtr conn,
         return (NULL);
     }
 
+#ifndef WITH_XEN_INOTIFY
     if (xenXMConfigCacheRefresh (conn) < 0)
         return (NULL);
+#endif
 
     if (!(entry = virHashSearch(configCache, xenXMDomainSearchForUUID, (const void *)uuid))) {
         return (NULL);
@@ -2208,8 +2266,10 @@ virDomainPtr xenXMDomainDefineXML(virConnectPtr conn, const char *xml) {
     if (conn->flags & VIR_CONNECT_RO)
         return (NULL);
 
+#ifndef WITH_XEN_INOTIFY
     if (xenXMConfigCacheRefresh (conn) < 0)
         return (NULL);
+#endif
 
     if (!(def = virDomainDefParseString(conn, priv->caps, xml)))
         return (NULL);
@@ -2376,8 +2436,10 @@ int xenXMListDefinedDomains(virConnectPtr conn, char **const names, int maxnames
         return (-1);
     }
 
+#ifndef WITH_XEN_INOTIFY
     if (xenXMConfigCacheRefresh (conn) < 0)
         return (-1);
+#endif
 
     if (maxnames > virHashSize(configCache))
         maxnames = virHashSize(configCache);
@@ -2401,8 +2463,10 @@ int xenXMNumOfDefinedDomains(virConnectPtr conn) {
         return (-1);
     }
 
+#ifndef WITH_XEN_INOTIFY
     if (xenXMConfigCacheRefresh (conn) < 0)
         return (-1);
+#endif
 
     return virHashSize(nameConfigMap);
 }

src/xm_internal.h

@@ -32,6 +32,12 @@
 extern struct xenUnifiedDriver xenXMDriver;
 int xenXMInit (void);
 
+virHashTablePtr xenXMGetConfigCache(void);
+char *xenXMGetConfigDir(void);
+int xenXMConfigCacheRefresh (virConnectPtr conn);
+int xenXMConfigCacheAddFile(virConnectPtr conn, const char *filename);
+int xenXMConfigCacheRemoveFile(virConnectPtr conn, const char *filename);
+
 int xenXMOpen(virConnectPtr conn, virConnectAuthPtr auth, int flags);
 int xenXMClose(virConnectPtr conn);
 const char *xenXMGetType(virConnectPtr conn);

src/xs_internal.c

@@ -29,6 +29,10 @@
 #include "virterror_internal.h"
 #include "datatypes.h"
 #include "driver.h"
+#include "memory.h"
+#include "event.h"
+#include "logging.h"
+#include "uuid.h"
 #include "xen_unified.h"
 #include "xs_internal.h"
 #include "xen_internal.h" /* for xenHypervisorCheckID */
@@ -42,6 +46,9 @@
 #endif
 
 #ifndef PROXY
+/* A list of active domain name/uuids */
+static xenUnifiedDomainInfoListPtr activeDomainList = NULL;
+
 static char *xenStoreDomainGetOSType(virDomainPtr domain);
 
 struct xenUnifiedDriver xenStoreDriver = {
@@ -302,7 +309,52 @@ xenStoreOpen(virConnectPtr conn,
         }
         return (-1);
     }
-    return (0);
+
+#ifndef PROXY
+    /* Init activeDomainList */
+    if ( VIR_ALLOC(activeDomainList) < 0) {
+        virXenStoreError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                 "%s", _("failed to allocate activeDomainList"));
+        return -1;
+    }
+
+    /* Init watch list before filling in domInfoList,
+       so we can know if it is the first time through
+       when the callback fires */
+    if ( VIR_ALLOC(priv->xsWatchList) < 0 ) {
+        virXenStoreError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                 "%s", _("failed to allocate xsWatchList"));
+        return -1;
+    }
+
+    /* This will get called once at start */
+    if ( xenStoreAddWatch(conn, "@releaseDomain",
+                     "releaseDomain", xenStoreDomainReleased, priv) < 0 )
+    {
+        virXenStoreError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                 "%s", _("adding watch @releaseDomain"));
+        return -1;
+    }
+
+    /* The initial call of this will fill domInfoList */
+    if( xenStoreAddWatch(conn, "@introduceDomain",
+                     "introduceDomain", xenStoreDomainIntroduced, priv) < 0 )
+    {
+        virXenStoreError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                 "%s", _("adding watch @introduceDomain"));
+        return -1;
+    }
+
+    /* Add an event handle */
+    if ((priv->xsWatch = virEventAddHandle(xs_fileno(priv->xshandle),
+                                           VIR_EVENT_HANDLE_READABLE,
+                                           xenStoreWatchEvent,
+                                           conn,
+                                           NULL)) < 0)
+        DEBUG0("Failed to add event handle, disabling events\n");
+
+#endif //PROXY
+    return 0;
 }
 
 /**
@@ -324,10 +376,29 @@ xenStoreClose(virConnectPtr conn)
     }
 
     priv = (xenUnifiedPrivatePtr) conn->privateData;
+
+    if (xenStoreRemoveWatch(conn, "@introduceDomain", "introduceDomain") < 0) {
+        DEBUG0("Warning, could not remove @introduceDomain watch");
+        /* not fatal */
+    }
+
+    if (xenStoreRemoveWatch(conn, "@releaseDomain", "releaseDomain") < 0) {
+        DEBUG0("Warning, could not remove @releaseDomain watch");
+        /* not fatal */
+    }
+
+    xenStoreWatchListFree(priv->xsWatchList);
+#ifndef PROXY
+    xenUnifiedDomainInfoListFree(activeDomainList);
+#endif
     if (priv->xshandle == NULL)
         return(-1);
 
+    if (priv->xsWatch != -1)
+        virEventRemoveHandle(priv->xsWatch);
     xs_daemon_close(priv->xshandle);
+    priv->xshandle = NULL;
+
     return (0);
 }
 
@@ -920,3 +991,343 @@ char *xenStoreDomainGetName(virConnectPtr conn,
     return xs_read(priv->xshandle, 0, prop, &len);
 }
 
+#ifndef PROXY
+int xenStoreDomainGetUUID(virConnectPtr conn,
+                          int id,
+                          unsigned char *uuid) {
+    char prop[200];
+    xenUnifiedPrivatePtr priv;
+    unsigned int len;
+    char *uuidstr;
+    int ret = 0;
+
+    priv = (xenUnifiedPrivatePtr) conn->privateData;
+    if (priv->xshandle == NULL)
+        return -1;
+
+    snprintf(prop, 199, "/local/domain/%d/vm", id);
+    prop[199] = 0;
+    // This will return something like
+    // /vm/00000000-0000-0000-0000-000000000000
+    uuidstr = xs_read(priv->xshandle, 0, prop, &len);
+
+    // remove "/vm/"
+    ret = virUUIDParse(uuidstr + 4, uuid);
+
+    VIR_FREE(uuidstr);
+
+    return ret;
+}
+#endif //PROXY
+
+void xenStoreWatchListFree(xenStoreWatchListPtr list)
+{
+    int i;
+    for (i=0; i<list->count; i++) {
+        VIR_FREE(list->watches[i]->path);
+        VIR_FREE(list->watches[i]->token);
+        VIR_FREE(list->watches[i]);
+    }
+    VIR_FREE(list);
+}
+
+int xenStoreAddWatch(virConnectPtr conn,
+                     const char *path,
+                     const char *token,
+                     xenStoreWatchCallback cb,
+                     void *opaque)
+{
+    xenStoreWatchPtr watch;
+    int n;
+    xenStoreWatchListPtr list;
+    xenUnifiedPrivatePtr priv = (xenUnifiedPrivatePtr) conn->privateData;
+
+    if (priv->xshandle == NULL)
+        return -1;
+
+    list = priv->xsWatchList;
+    if(!list)
+        return -1;
+
+    /* check if we already have this callback on our list */
+    for (n=0; n < list->count; n++) {
+        if( STREQ(list->watches[n]->path, path) &&
+            STREQ(list->watches[n]->token, token)) {
+            virXenStoreError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                 "%s", _("watch already tracked"));
+            return -1;
+        }
+    }
+
+    if (VIR_ALLOC(watch) < 0)
+        return -1;
+    watch->path   = strdup(path);
+    watch->token  = strdup(token);
+    watch->cb     = cb;
+    watch->opaque = opaque;
+
+    /* Make space on list */
+    n = list->count;
+    if (VIR_REALLOC_N(list->watches, n + 1) < 0) {
+        virXenStoreError(NULL, VIR_ERR_INTERNAL_ERROR,
+                                 "%s", _("reallocating list"));
+        VIR_FREE(watch);
+        return -1;
+    }
+
+    list->watches[n] = watch;
+    list->count++;
+
+    conn->refs++;
+
+    return xs_watch(priv->xshandle, watch->path, watch->token);
+}
+
+int xenStoreRemoveWatch(virConnectPtr conn,
+                        const char *path,
+                        const char *token)
+{
+    int i;
+    xenStoreWatchListPtr list;
+    xenUnifiedPrivatePtr priv = (xenUnifiedPrivatePtr) conn->privateData;
+
+    if (priv->xshandle == NULL)
+        return -1;
+
+    list = priv->xsWatchList;
+    if(!list)
+        return -1;
+
+    for (i = 0 ; i < list->count ; i++) {
+        if( STREQ(list->watches[i]->path, path) &&
+            STREQ(list->watches[i]->token, token)) {
+
+            if (!xs_unwatch(priv->xshandle,
+                       list->watches[i]->path,
+                       list->watches[i]->path))
+            {
+                DEBUG0("WARNING: Could not remove watch");
+                /* Not fatal, continue */
+            }
+
+            VIR_FREE(list->watches[i]->path);
+            VIR_FREE(list->watches[i]->token);
+            VIR_FREE(list->watches[i]);
+
+            if (i < (list->count - 1))
+                memmove(list->watches + i,
+                        list->watches + i + 1,
+                        sizeof(*(list->watches)) *
+                                (list->count - (i + 1)));
+
+            if (VIR_REALLOC_N(list->watches,
+                              list->count - 1) < 0) {
+                ; /* Failure to reduce memory allocation isn't fatal */
+            }
+            list->count--;
+#ifndef PROXY
+            virUnrefConnect(conn);
+#endif
+            return 0;
+        }
+    }
+    return -1;
+}
+
+xenStoreWatchPtr xenStoreFindWatch(xenStoreWatchListPtr list,
+                                   const char *path,
+                                   const char *token)
+{
+    int i;
+    for (i = 0 ; i < list->count ; i++)
+        if( STREQ(path, list->watches[i]->path) &&
+            STREQ(token, list->watches[i]->token) )
+            return list->watches[i];
+
+    return NULL;
+}
+
+void xenStoreWatchEvent(int watch ATTRIBUTE_UNUSED,
+                        int fd ATTRIBUTE_UNUSED,
+                        int events ATTRIBUTE_UNUSED,
+                        void *data)
+{
+    char		 **event;
+    char		 *path;
+    char		 *token;
+    unsigned int	 stringCount;
+    xenStoreWatchPtr     sw;
+
+    virConnectPtr        conn = data;
+    xenUnifiedPrivatePtr priv = (xenUnifiedPrivatePtr) conn->privateData;
+    if(!priv) return;
+    if(!priv->xshandle) return;
+
+    event = xs_read_watch(priv->xshandle, &stringCount);
+    if (!event)
+        return;
+
+    path  = event[XS_WATCH_PATH];
+    token = event[XS_WATCH_TOKEN];
+
+    sw = xenStoreFindWatch(priv->xsWatchList, path, token);
+    if( sw )
+        sw->cb(conn, path, token, sw->opaque);
+    VIR_FREE(event);
+}
+
+#ifndef PROXY
+/* The domain callback for the @introduceDomain watch */
+int xenStoreDomainIntroduced(virConnectPtr conn,
+                             const char *path ATTRIBUTE_UNUSED,
+                             const char *token ATTRIBUTE_UNUSED,
+                             void *opaque)
+{
+    int i, j, found, missing = 0, retries = 20;
+    int new_domain_cnt;
+    int *new_domids;
+    int nread;
+
+    xenUnifiedPrivatePtr priv = (xenUnifiedPrivatePtr) opaque;
+
+retry:
+    new_domain_cnt = xenStoreNumOfDomains(conn);
+    if( VIR_ALLOC_N(new_domids,new_domain_cnt) < 0 ) {
+        virXenStoreError(NULL, VIR_ERR_NO_MEMORY,
+                                 "%s", _("failed to allocate domids"));
+        return -1;
+    }
+    nread = xenStoreListDomains(conn, new_domids, new_domain_cnt);
+    if (nread != new_domain_cnt) {
+        // mismatch. retry this read
+        VIR_FREE(new_domids);
+        goto retry;
+    }
+
+    missing = 0;
+    for (i=0 ; i < new_domain_cnt ; i++) {
+        found = 0;
+        for (j = 0 ; j < activeDomainList->count ; j++) {
+            if (activeDomainList->doms[j]->id == new_domids[i]) {
+                found = 1;
+                break;
+            }
+        }
+
+        if (!found) {
+            virDomainPtr dom;
+            char *name;
+            unsigned char uuid[VIR_UUID_BUFLEN];
+
+            if (!(name = xenStoreDomainGetName(conn, new_domids[i]))) {
+                missing = 1;
+                continue;
+            }
+            if (xenStoreDomainGetUUID(conn, new_domids[i], uuid) < 0) {
+                missing = 1;
+                VIR_FREE(name);
+                continue;
+            }
+
+            dom = virGetDomain(conn, name, uuid);
+            if (dom) {
+                dom->id = new_domids[i];
+
+                /* This domain was not in the old list. Emit an event */
+                xenUnifiedDomainEventDispatch(priv, dom,
+                                              VIR_DOMAIN_EVENT_STARTED,
+                                              VIR_DOMAIN_EVENT_STARTED_BOOTED);
+
+                /* Add to the list */
+                xenUnifiedAddDomainInfo(activeDomainList,
+                                        new_domids[i], name, uuid);
+
+                virUnrefDomain(dom);
+            }
+
+            VIR_FREE(name);
+        }
+    }
+    VIR_FREE(new_domids);
+
+    if (missing && retries--) {
+        DEBUG0("Some domains were missing, trying again");
+        usleep(100 * 1000);
+        goto retry;
+    }
+    return 0;
+}
+
+/* The domain callback for the @destroyDomain watch */
+int xenStoreDomainReleased(virConnectPtr conn,
+                            const char *path  ATTRIBUTE_UNUSED,
+                            const char *token ATTRIBUTE_UNUSED,
+                            void *opaque)
+{
+    int i, j, found, removed, retries = 20;
+    int new_domain_cnt;
+    int *new_domids;
+    int nread;
+
+    xenUnifiedPrivatePtr priv = (xenUnifiedPrivatePtr) opaque;
+
+    if(!activeDomainList->count) return 0;
+
+retry:
+    new_domain_cnt = xenStoreNumOfDomains(conn);
+
+    if( VIR_ALLOC_N(new_domids,new_domain_cnt) < 0 ) {
+        virXenStoreError(NULL, VIR_ERR_NO_MEMORY,
+                                 "%s", _("failed to allocate domids"));
+        return -1;
+    }
+    nread = xenStoreListDomains(conn, new_domids, new_domain_cnt);
+    if (nread != new_domain_cnt) {
+        // mismatch. retry this read
+        VIR_FREE(new_domids);
+        goto retry;
+    }
+
+    removed = 0;
+    for (j=0 ; j < activeDomainList->count ; j++) {
+        found = 0;
+        for (i=0 ; i < new_domain_cnt ; i++) {
+            if (activeDomainList->doms[j]->id == new_domids[i]) {
+                found = 1;
+                break;
+            }
+        }
+
+        if (!found) {
+            virDomainPtr dom = virGetDomain(conn,
+                                            activeDomainList->doms[j]->name,
+                                            activeDomainList->doms[j]->uuid);
+            if(dom) {
+                dom->id = -1;
+                /* This domain was not in the new list. Emit an event */
+                xenUnifiedDomainEventDispatch(priv, dom,
+                                              VIR_DOMAIN_EVENT_STOPPED,
+                                              VIR_DOMAIN_EVENT_STOPPED_SHUTDOWN);
+                 /* Remove from the list */
+                xenUnifiedRemoveDomainInfo(activeDomainList,
+                                           activeDomainList->doms[j]->id,
+                                           activeDomainList->doms[j]->name,
+                                           activeDomainList->doms[j]->uuid);
+
+                virUnrefDomain(dom);
+                removed = 1;
+            }
+        }
+    }
+
+    VIR_FREE(new_domids);
+
+    if (!removed && retries--) {
+        DEBUG0("No domains removed, retrying");
+        usleep(100 * 1000);
+        goto retry;
+    }
+    return 0;
+}
+
+#endif //PROXY

src/xs_internal.h

@@ -51,5 +51,57 @@ char *		xenStoreDomainGetDiskID(virConnectPtr conn,
                                          const char *dev);
 char *          xenStoreDomainGetName(virConnectPtr conn,
                                       int id);
+int             xenStoreDomainGetUUID(virConnectPtr conn,
+                                      int id,
+                                      unsigned char *uuid);
 
+typedef int (*xenStoreWatchCallback)(virConnectPtr conn,
+                                     const char *path,
+                                     const char *token,
+                                     void *opaque);
+
+struct _xenStoreWatch {
+    char *path;
+    char *token;
+    xenStoreWatchCallback cb;
+    void *opaque;
+};
+typedef struct _xenStoreWatch xenStoreWatch;
+typedef xenStoreWatch *xenStoreWatchPtr;
+
+struct _xenStoreWatchList {
+    unsigned int count;
+    xenStoreWatchPtr *watches;
+};
+typedef struct _xenStoreWatchList xenStoreWatchList;
+typedef xenStoreWatchList *xenStoreWatchListPtr;
+
+
+void            xenStoreWatchListFree(xenStoreWatchListPtr head);
+
+int             xenStoreAddWatch(virConnectPtr conn,
+                                 const char *path,
+                                 const char *token,
+                                 xenStoreWatchCallback cb,
+                                 void *opaque);
+int             xenStoreRemoveWatch(virConnectPtr conn,
+                                    const char *path,
+                                    const char *token);
+xenStoreWatchPtr xenStoreFindWatch(xenStoreWatchListPtr list,
+                                  const char *path,
+                                  const char *token);
+
+void xenStoreWatchEvent(int watch, int fd, int events, void *data);
+
+/* domain events */
+int xenStoreDomainIntroduced(virConnectPtr conn,
+                             const char *path,
+                             const char *token,
+                             void *opaque);
+int xenStoreDomainReleased(virConnectPtr conn,
+                            const char *path,
+                            const char *token,
+                            void *opaque);
+
+int xenStoreDomainEventEmitted(virDomainEventType evt);
 #endif /* __VIR_XS_INTERNAL_H__ */