xl: handle domain shutdown/reboot/crash in a user configurable way

diff -r 74c8b1f2c2da -r 7a0c37f2a9b5 tools/libxl/libxl.c
@@ -643,7 +643,7 @@ int libxl_wait_for_domain_death(struct l
 int libxl_wait_for_domain_death(struct libxl_ctx *ctx, uint32_t domid, libxl_waiter *waiter)
 {
     waiter->path = strdup("@releaseDomain");
-    if (asprintf(&(waiter->token), "%d", DOMAIN_DEATH) < 0)
+    if (asprintf(&(waiter->token), "%d", LIBXL_EVENT_DOMAIN_DEATH) < 0)
         return -1;
     if (!xs_watch(ctx->xsh, waiter->path, waiter->token))
         return -1;

@@ -663,7 +663,7 @@ int libxl_wait_for_disk_ejects(struct li
                      libxl_xs_get_dompath(ctx, domid),
                      device_disk_dev_number(disks[i].virtpath)) < 0)
             return -1;
-        if (asprintf(&(waiter[i].token), "%d", DISK_EJECT) < 0)
+        if (asprintf(&(waiter[i].token), "%d", LIBXL_EVENT_DISK_EJECT) < 0)
             return -1;
         xs_watch(ctx->xsh, waiter->path, waiter->token);
     }

@@ -711,7 +711,7 @@ int libxl_event_get_domain_death_info(st
 {
     int rc = 0, ret;
 
-    if (event && event->type == DOMAIN_DEATH) {
+    if (event && event->type == LIBXL_EVENT_DOMAIN_DEATH) {
         ret = xc_domain_getinfolist(ctx->xch, domid, 1, info);
         if (ret == 1 && info->domain == domid) {
                 if (info->flags & XEN_DOMINF_running ||

@@ -730,7 +730,7 @@ out:
 
 int libxl_event_get_disk_eject_info(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, libxl_device_disk *disk)
 {
-    if (event && event->type == DISK_EJECT) {
+    if (event && event->type == LIBXL_EVENT_DISK_EJECT) {
         char *path;
         char *backend;
         char *value = libxl_xs_read(ctx, XBT_NULL, event->path);

diff -r 74c8b1f2c2da -r 7a0c37f2a9b5 tools/libxl/libxl.h
@@ -357,8 +357,8 @@ char *libxl_uuid2string(struct libxl_ctx
 /* events handling */
 
 typedef enum {
-    DOMAIN_DEATH,
-    DISK_EJECT,
+    LIBXL_EVENT_DOMAIN_DEATH,
+    LIBXL_EVENT_DISK_EJECT,
 } libxl_event_type;
 
 typedef struct {

diff -r 74c8b1f2c2da -r 7a0c37f2a9b5 tools/libxl/xl_cmdimpl.c
@@ -1348,7 +1348,7 @@ start:
             continue;
         libxl_get_event(&ctx, &event);
         switch (event.type) {
-            case DOMAIN_DEATH:
+            case LIBXL_EVENT_DOMAIN_DEATH:
                 if (libxl_event_get_domain_death_info(&ctx, domid, &event, &info)) {
                     LOG("Domain %d is dead", domid);
                     if (info.flags & XEN_DOMINF_dying || (info.flags & XEN_DOMINF_shutdown && (((info.flags >> XEN_DOMINF_shutdownshift) & XEN_DOMINF_shutdownmask) != SHUTDOWN_suspend))) {

@@ -1374,7 +1374,7 @@ start:
                     exit(0);
                 }
                 break;
-            case DISK_EJECT:
+            case LIBXL_EVENT_DISK_EJECT:
                 if (libxl_event_get_disk_eject_info(&ctx, domid, &event, &disk))
                     libxl_cdrom_insert(&ctx, domid, &disk);
                 break;

diff -r 7a0c37f2a9b5 -r 74371f414f20 tools/libxl/libxl.c
@@ -405,8 +405,6 @@ static void xcinfo2xlinfo(const xc_domai
 static void xcinfo2xlinfo(const xc_domaininfo_t *xcinfo,
                           struct libxl_dominfo *xlinfo)
 {
-    unsigned int shutdown_reason;
-
     memcpy(&(xlinfo->uuid), xcinfo->handle, sizeof(xen_domain_handle_t));
     xlinfo->domid = xcinfo->domain;
 

@@ -415,14 +413,11 @@ static void xcinfo2xlinfo(const xc_domai
     xlinfo->paused   = !!(xcinfo->flags&XEN_DOMINF_paused);
     xlinfo->blocked  = !!(xcinfo->flags&XEN_DOMINF_blocked);
     xlinfo->running  = !!(xcinfo->flags&XEN_DOMINF_running);
-    xlinfo->crashed  = 0;
 
-    shutdown_reason = (xcinfo->flags>>XEN_DOMINF_shutdownshift) & XEN_DOMINF_shutdownmask;
-
-    if ( xlinfo->shutdown && (shutdown_reason == SHUTDOWN_crash) ) {
-        xlinfo->shutdown = 0;
-        xlinfo->crashed  = 1;
-    }
+    if (xlinfo->shutdown || xlinfo->dying)
+        xlinfo->shutdown_reason = (xcinfo->flags>>XEN_DOMINF_shutdownshift) & XEN_DOMINF_shutdownmask;
+    else
+        xlinfo->shutdown_reason  = ~0;
 
     xlinfo->max_memkb = PAGE_TO_MEMKB(xcinfo->tot_pages);
     xlinfo->cpu_time = xcinfo->cpu_time;

diff -r 7a0c37f2a9b5 -r 74371f414f20 tools/libxl/libxl.h
@@ -29,8 +29,16 @@ struct libxl_dominfo {
     uint8_t blocked:1;
     uint8_t paused:1;
     uint8_t shutdown:1;
-    uint8_t crashed:1;
     uint8_t dying:1;
+
+    /*
+     * Valid SHUTDOWN_* value from xen/sched.h iff (shutdown||dying).
+     *
+     * Otherwise set to a value guaranteed not to clash with any valid
+     * SHUTDOWN_* constant.
+     */
+    unsigned int shutdown_reason;
+
     uint64_t max_memkb;
     uint64_t cpu_time;
     uint32_t vcpu_max_id;

diff -r 7a0c37f2a9b5 -r 74371f414f20 tools/libxl/xl_cmdimpl.c
@@ -1935,7 +1935,7 @@ void list_domains(int verbose)
                 info[i].blocked ? 'b' : '-',
                 info[i].paused ? 'p' : '-',
                 info[i].shutdown ? 's' : '-',
-                info[i].crashed ? 'c' : '-',
+                info[i].shutdown_reason == SHUTDOWN_crash ? 'c' : '-',
                 info[i].dying ? 'd' : '-',
                 ((float)info[i].cpu_time / 1e9));
         if (verbose) {

diff -r 74371f414f20 -r 8774eec37219 tools/libxl/libxl.c
@@ -702,20 +702,19 @@ int libxl_free_waiter(libxl_waiter *wait
     return 0;
 }
 
-int libxl_event_get_domain_death_info(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, xc_domaininfo_t *info)
+int libxl_event_get_domain_death_info(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, struct libxl_dominfo *info)
 {
     int rc = 0, ret;
+    if (event && event->type == LIBXL_EVENT_DOMAIN_DEATH) {
+        ret = libxl_domain_info(ctx, info, domid);
 
-    if (event && event->type == LIBXL_EVENT_DOMAIN_DEATH) {
-        ret = xc_domain_getinfolist(ctx->xch, domid, 1, info);
-        if (ret == 1 && info->domain == domid) {
-                if (info->flags & XEN_DOMINF_running ||
-                    (!(info->flags & XEN_DOMINF_shutdown) && !(info->flags & XEN_DOMINF_dying)))
+        if (ret == 0 && info->domid == domid) {
+            if (info->running || (!info->shutdown && !info->dying))
                     goto out;
                 rc = 1;
                 goto out;
         }
-        memset(info, 0, sizeof(xc_dominfo_t));
+        memset(info, 0, sizeof(*info));
         rc = 1;
         goto out;
     }

diff -r 74371f414f20 -r 8774eec37219 tools/libxl/libxl.h
@@ -393,7 +393,7 @@ int libxl_free_event(libxl_event *event)
 int libxl_free_event(libxl_event *event);
 int libxl_free_waiter(libxl_waiter *waiter);
 
-int libxl_event_get_domain_death_info(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, xc_domaininfo_t *info);
+int libxl_event_get_domain_death_info(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, struct libxl_dominfo *info);
 int libxl_event_get_disk_eject_info(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, libxl_device_disk *disk);
 
 int libxl_domain_rename(struct libxl_ctx *ctx, uint32_t domid,

diff -r 74371f414f20 -r 8774eec37219 tools/libxl/xl_cmdimpl.c
@@ -1335,7 +1335,7 @@ start:
     while (1) {
         int ret;
         fd_set rfds;
-        xc_domaininfo_t info;
+        struct libxl_dominfo info;
         libxl_event event;
         libxl_device_disk disk;
         memset(&info, 0x00, sizeof(xc_domaininfo_t));

@@ -1351,11 +1351,10 @@ start:
             case LIBXL_EVENT_DOMAIN_DEATH:
                 if (libxl_event_get_domain_death_info(&ctx, domid, &event, &info)) {
                     LOG("Domain %d is dead", domid);
-                    if (info.flags & XEN_DOMINF_dying || (info.flags & XEN_DOMINF_shutdown && (((info.flags >> XEN_DOMINF_shutdownshift) & XEN_DOMINF_shutdownmask) != SHUTDOWN_suspend))) {
+                    if (info.dying || (info.shutdown && info.shutdown_reason != SHUTDOWN_suspend)) {
                         LOG("Domain %d needs to be clean: destroying the domain", domid);
                         libxl_domain_destroy(&ctx, domid, 0);
-                        if (info.flags & XEN_DOMINF_shutdown &&
-                            (((info.flags >> XEN_DOMINF_shutdownshift) & XEN_DOMINF_shutdownmask) == SHUTDOWN_reboot)) {
+                        if (info.shutdown && info.shutdown_reason == SHUTDOWN_reboot) {
                             libxl_free_waiter(w1);
                             libxl_free_waiter(w2);
                             free(w1);

diff -r 8774eec37219 -r 4e16c19ba1ac tools/libxl/libxl.c
@@ -704,52 +704,42 @@ int libxl_free_waiter(libxl_waiter *wait
 
 int libxl_event_get_domain_death_info(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, struct libxl_dominfo *info)
 {
-    int rc = 0, ret;
-    if (event && event->type == LIBXL_EVENT_DOMAIN_DEATH) {
-        ret = libxl_domain_info(ctx, info, domid);
+    if (libxl_domain_info(ctx, info, domid) < 0)
+        return 0;
 
-        if (ret == 0 && info->domid == domid) {
-            if (info->running || (!info->shutdown && !info->dying))
-                    goto out;
-                rc = 1;
-                goto out;
-        }
-        memset(info, 0, sizeof(*info));
-        rc = 1;
-        goto out;
-    }
-out:
-    return rc;
+    if (info->running || (!info->shutdown && !info->dying))
+        return ERROR_INVAL;
+
+    return 1;
 }
 
 int libxl_event_get_disk_eject_info(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, libxl_device_disk *disk)
 {
-    if (event && event->type == LIBXL_EVENT_DISK_EJECT) {
-        char *path;
-        char *backend;
-        char *value = libxl_xs_read(ctx, XBT_NULL, event->path);
+    char *path;
+    char *backend;
+    char *value;
 
-        if (!value || strcmp(value,  "eject"))
-            return 0;
+    value = libxl_xs_read(ctx, XBT_NULL, event->path);
 
-        path = strdup(event->path);
-        path[strlen(path) - 6] = '\0';
-        backend = libxl_xs_read(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/backend", path));
+    if (!value || strcmp(value,  "eject"))
+        return 0;
 
-        disk->backend_domid = 0;
-        disk->domid = domid;
-        disk->physpath = NULL;
-        disk->phystype = 0;
-        /* this value is returned to the user: do not free right away */
-        disk->virtpath = libxl_xs_read(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/dev", backend));
-        disk->unpluggable = 1;
-        disk->readwrite = 0;
-        disk->is_cdrom = 1;
+    path = strdup(event->path);
+    path[strlen(path) - 6] = '\0';
+    backend = libxl_xs_read(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/backend", path));
 
-        free(path);
-        return 1;
-    }
-    return 0;
+    disk->backend_domid = 0;
+    disk->domid = domid;
+    disk->physpath = NULL;
+    disk->phystype = 0;
+    /* this value is returned to the user: do not free right away */
+    disk->virtpath = libxl_xs_read(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/dev", backend));
+    disk->unpluggable = 1;
+    disk->readwrite = 0;
+    disk->is_cdrom = 1;
+
+    free(path);
+    return 1;
 }
 
 static int libxl_destroy_device_model(struct libxl_ctx *ctx, uint32_t domid)

diff -r 8774eec37219 -r 4e16c19ba1ac tools/libxl/libxl.h
@@ -393,7 +393,24 @@ int libxl_free_event(libxl_event *event)
 int libxl_free_event(libxl_event *event);
 int libxl_free_waiter(libxl_waiter *waiter);
 
+/*
+ * Returns:
+ *  - 0 if the domain is dead but there is no cleanup to be done. e.g
+ *    because someone else has already done it.
+ *  - 1 if the domain is dead and there is cleanup to be done.
+ *
+ * Can return error if the domain exists and is still running.
+ *
+ * *info will contain valid domain state iff 1 is returned. In
+ * particular if 1 is returned then info->shutdown_reason is
+ * guaranteed to be valid since by definition the domain is
+ * (shutdown||dying))
+ */
 int libxl_event_get_domain_death_info(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, struct libxl_dominfo *info);
+
+/*
+ * Returns true and fills *disk if the caller should eject the disk
+ */
 int libxl_event_get_disk_eject_info(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, libxl_device_disk *disk);
 
 int libxl_domain_rename(struct libxl_ctx *ctx, uint32_t domid,

diff -r 8774eec37219 -r 4e16c19ba1ac tools/libxl/xl_cmdimpl.c
@@ -1338,7 +1338,6 @@ start:
         struct libxl_dominfo info;
         libxl_event event;
         libxl_device_disk disk;
-        memset(&info, 0x00, sizeof(xc_domaininfo_t));
 
         FD_ZERO(&rfds);
         FD_SET(fd, &rfds);

@@ -1349,12 +1348,17 @@ start:
         libxl_get_event(&ctx, &event);
         switch (event.type) {
             case LIBXL_EVENT_DOMAIN_DEATH:
-                if (libxl_event_get_domain_death_info(&ctx, domid, &event, &info)) {
-                    LOG("Domain %d is dead", domid);
-                    if (info.dying || (info.shutdown && info.shutdown_reason != SHUTDOWN_suspend)) {
+                ret = libxl_event_get_domain_death_info(&ctx, domid, &event, &info);
+
+                if (ret < 0) continue;
+
+                LOG("Domain %d is dead", domid);
+
+                if (ret) {
+                    if (info.shutdown_reason != SHUTDOWN_suspend) {
                         LOG("Domain %d needs to be clean: destroying the domain", domid);
                         libxl_domain_destroy(&ctx, domid, 0);
-                        if (info.shutdown && info.shutdown_reason == SHUTDOWN_reboot) {
+                        if (info.shutdown_reason == SHUTDOWN_reboot) {
                             libxl_free_waiter(w1);
                             libxl_free_waiter(w2);
                             free(w1);

diff -r 4e16c19ba1ac -r a31105a3eb9d tools/libxl/xl_cmdimpl.c
@@ -211,15 +211,19 @@ static void init_build_info(libxl_domain
     }
 }
 
+static void random_uuid(uint8_t *uuid)
+{
+    int i;
+    for (i = 0; i < 16; i++)
+        uuid[i] = rand();
+}
+
 static void init_dm_info(libxl_device_model_info *dm_info,
         libxl_domain_create_info *c_info, libxl_domain_build_info *b_info)
 {
-    int i;
     memset(dm_info, '\0', sizeof(*dm_info));
 
-    for (i = 0; i < 16; i++) {
-        dm_info->uuid[i] = rand();
-    }
+    random_uuid(&dm_info->uuid[0]);
 
     dm_info->dom_name = c_info->name;
     dm_info->device_model = "qemu-dm";

@@ -493,7 +497,7 @@ static void parse_config_data(const char
     XLU_ConfigList *vbds, *nics, *pcis, *cvfbs, *net2s;
     int pci_power_mgmt = 0;
     int pci_msitranslate = 1;
-    int i, e;
+    int e;
 
     config= xlu_cfg_init(stderr, configfile_filename_report);
     if (!config) {

@@ -521,9 +525,7 @@ static void parse_config_data(const char
         c_info->name = strdup(buf);
     else
         c_info->name = "test";
-    for (i = 0; i < 16; i++) {
-        c_info->uuid[i] = rand();
-    }
+    random_uuid(&c_info->uuid[0]);
 
     if (!xlu_cfg_get_long(config, "oos", &l))
         c_info->oos = l;

diff -r a31105a3eb9d -r b87962af9df2 tools/libxl/xl_cmdimpl.c
@@ -988,6 +988,18 @@ int autoconnect_console(int hvm)
     _exit(1);
 }
 
+/* Returns 1 if domain should be restarted */
+static int handle_domain_death(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, struct libxl_dominfo *info)
+{
+    if (info->shutdown_reason != SHUTDOWN_suspend) {
+        LOG("Domain %d needs to be clean: destroying the domain", domid);
+        libxl_domain_destroy(ctx, domid, 0);
+        if (info->shutdown_reason == SHUTDOWN_reboot)
+            return 1;
+    }
+    return 0;
+}
+
 struct domain_create {
     int debug;
     int daemonize;

@@ -1357,25 +1369,20 @@ start:
                 LOG("Domain %d is dead", domid);
 
                 if (ret) {
-                    if (info.shutdown_reason != SHUTDOWN_suspend) {
-                        LOG("Domain %d needs to be clean: destroying the domain", domid);
-                        libxl_domain_destroy(&ctx, domid, 0);
-                        if (info.shutdown_reason == SHUTDOWN_reboot) {
-                            libxl_free_waiter(w1);
-                            libxl_free_waiter(w2);
-                            free(w1);
-                            free(w2);
-                            LOG("Done. Rebooting now");
-                            /*
-                             * XXX FIXME: If this sleep is not there then
-                             * domain re-creation fails sometimes.
-                             */
-                            sleep(2);
-                            goto start;
-                        }
-                        LOG("Done. Exiting now");
+                    if (handle_domain_death(&ctx, domid, &event, &info)) {
+                        libxl_free_waiter(w1);
+                        libxl_free_waiter(w2);
+                        free(w1);
+                        free(w2);
+                        /*
+                         * XXX FIXME: If this sleep is not there then domain
+                         * re-creation fails sometimes.
+                         */
+                        LOG("Done. Rebooting now");
+                        sleep(2);
+                        goto start;
                     }
-                    LOG("Domain %d does not need to be clean, exiting now", domid);
+                    LOG("Done. Exiting now");
                     exit(0);
                 }
                 break;

diff -r b87962af9df2 -r 1c1b0c8bb58c tools/libxl/xl_cmdimpl.c
@@ -99,6 +99,36 @@ struct save_file_header {
     uint32_t optional_data_len; /* skip, or skip tail, if not understood */
 };
 
+
+enum action_on_shutdown {
+    ACTION_DESTROY,
+
+    ACTION_RESTART,
+
+    ACTION_PRESERVE,
+
+    ACTION_COREDUMP_DESTROY,
+    ACTION_COREDUMP_RESTART,
+};
+
+static char *action_on_shutdown_names[] = {
+    [ACTION_DESTROY] = "destroy",
+
+    [ACTION_RESTART] = "restart",
+
+    [ACTION_PRESERVE] = "preserve",
+
+    [ACTION_COREDUMP_DESTROY] = "coredump-destroy",
+    [ACTION_COREDUMP_RESTART] = "coredump-restart",
+};
+
+struct domain_config {
+    enum action_on_shutdown on_poweroff;
+    enum action_on_shutdown on_reboot;
+    enum action_on_shutdown on_watchdog;
+    enum action_on_shutdown on_crash;
+};
+
 /* Optional data, in order:
  *   4 bytes uint32_t  config file size
  *   n bytes           config file in Unix text file format

@@ -472,11 +502,28 @@ static void printf_info(int domid,
        printf(")\n");
 }
 
+static int parse_action_on_shutdown(const char *buf, enum action_on_shutdown *a)
+{
+    int i;
+    const char *n;
+
+    for (i = 0; i < sizeof(action_on_shutdown_names) / sizeof(action_on_shutdown_names[0]); i++) {
+        n = action_on_shutdown_names[i];
+
+        if (strcmp(buf, n) == 0) {
+            *a = i;
+            return 1;
+        }
+    }
+    return 0;
+}
+
 static void parse_config_data(const char *configfile_filename_report,
                               const char *configfile_data,
                               int configfile_len,
                               libxl_domain_create_info *c_info,
                               libxl_domain_build_info *b_info,
+                              struct domain_config *d_config,
                               libxl_device_disk **disks,
                               int *num_disks,
                               libxl_device_nic **vifs,

@@ -551,6 +598,35 @@ static void parse_config_data(const char
     if (!xlu_cfg_get_long (config, "memory", &l)) {
         b_info->max_memkb = l * 1024;
         b_info->target_memkb = b_info->max_memkb;
+    }
+
+    if (xlu_cfg_get_string (config, "on_poweroff", &buf))
+        buf = "destroy";
+    if (!parse_action_on_shutdown(buf, &d_config->on_poweroff)) {
+        fprintf(stderr, "Unknown on_poweroff action \"%s\" specified\n", buf);
+        exit(1);
+    }
+
+    if (xlu_cfg_get_string (config, "on_reboot", &buf))
+        buf = "restart";
+    if (!parse_action_on_shutdown(buf, &d_config->on_reboot)) {
+        fprintf(stderr, "Unknown on_reboot action \"%s\" specified\n", buf);
+        exit(1);
+    }
+
+    if (xlu_cfg_get_string (config, "on_watchdog", &buf))
+        buf = "destroy";
+    if (!parse_action_on_shutdown(buf, &d_config->on_watchdog)) {
+        fprintf(stderr, "Unknown on_watchdog action \"%s\" specified\n", buf);
+        exit(1);
+    }
+
+
+    if (xlu_cfg_get_string (config, "on_crash", &buf))
+        buf = "destroy";
+    if (!parse_action_on_shutdown(buf, &d_config->on_crash)) {
+        fprintf(stderr, "Unknown on_crash action \"%s\" specified\n", buf);
+        exit(1);
     }
 
     /* libxl_get_required_shadow_memory() must be called after final values

@@ -989,15 +1065,70 @@ int autoconnect_console(int hvm)
 }
 
 /* Returns 1 if domain should be restarted */
-static int handle_domain_death(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event, struct libxl_dominfo *info)
-{
-    if (info->shutdown_reason != SHUTDOWN_suspend) {
-        LOG("Domain %d needs to be clean: destroying the domain", domid);
+static int handle_domain_death(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event,
+                               libxl_domain_create_info *c_info,
+                               struct domain_config *d_config, struct libxl_dominfo *info)
+{
+    int restart = 0;
+    enum action_on_shutdown action;
+
+    switch (info->shutdown_reason) {
+    case SHUTDOWN_poweroff:
+        action = d_config->on_poweroff;
+        break;
+    case SHUTDOWN_reboot:
+        action = d_config->on_reboot;
+        break;
+    case SHUTDOWN_suspend:
+        return 0;
+    case SHUTDOWN_crash:
+        action = d_config->on_crash;
+        break;
+    case SHUTDOWN_watchdog:
+        action = d_config->on_watchdog;
+        break;
+    }
+
+    LOG("Action for shutdown reason code %d is %s", info->shutdown_reason, action_on_shutdown_names[action]);
+
+    if (action == ACTION_COREDUMP_DESTROY || action == ACTION_COREDUMP_RESTART) {
+        char *corefile;
+        int rc;
+
+        if (asprintf(&corefile, "/var/xen/dump/%s", c_info->name) < 0) {
+            LOG("failed to construct core dump path");
+        } else {
+            LOG("dumping core to %s", corefile);
+            rc=libxl_domain_core_dump(ctx, domid, corefile);
+            if (rc) LOG("core dump failed (rc=%d).", rc);
+        }
+        /* No point crying over spilled milk, continue on failure. */
+
+        if (action == ACTION_COREDUMP_DESTROY)
+            action = ACTION_DESTROY;
+        else
+            action = ACTION_RESTART;
+    }
+
+    switch (action) {
+    case ACTION_PRESERVE:
+        break;
+
+    case ACTION_RESTART:
+        restart = 1;
+        /* fall-through */
+    case ACTION_DESTROY:
+        LOG("Domain %d needs to be cleaned up: destroying the domain", domid);
         libxl_domain_destroy(ctx, domid, 0);
-        if (info->shutdown_reason == SHUTDOWN_reboot)
-            return 1;
-    }
-    return 0;
+        break;
+
+    case ACTION_COREDUMP_DESTROY:
+    case ACTION_COREDUMP_RESTART:
+        /* Already handled these above. */
+        abort();
+    }
+
+    return restart;
 }
 
 struct domain_create {

@@ -1016,6 +1147,8 @@ struct domain_create {
 
 static int create_domain(struct domain_create *dom_info)
 {
+    struct domain_config d_config;
+
     libxl_domain_create_info c_info;
     libxl_domain_build_info b_info;
     libxl_domain_build_state state;

@@ -1150,7 +1283,7 @@ static int create_domain(struct domain_c
     if (!dom_info->quiet)
         printf("Parsing config file %s\n", config_file);
 
-    parse_config_data(config_file, config_data, config_len, &c_info, &b_info, &disks, &num_disks, &vifs, &num_vifs, &vif2s, &num_vif2s, &pcidevs, &num_pcidevs, &vfbs, &num_vfbs, &vkbs, &num_vkbs, &dm_info);
+    parse_config_data(config_file, config_data, config_len, &c_info, &b_info, &d_config, &disks, &num_disks, &vifs, &num_vifs, &vif2s, &num_vif2s, &pcidevs, &num_pcidevs, &vfbs, &num_vfbs, &vkbs, &num_vkbs, &dm_info);
 
     if (dom_info->dryrun)
         return 0;

@@ -1369,7 +1502,7 @@ start:
                 LOG("Domain %d is dead", domid);
 
                 if (ret) {
-                    if (handle_domain_death(&ctx, domid, &event, &info)) {
+                    if (handle_domain_death(&ctx, domid, &event, &c_info, &d_config, &info)) {
                         libxl_free_waiter(w1);
                         libxl_free_waiter(w2);
                         free(w1);

@@ -1892,6 +2025,8 @@ void list_domains_details(void)
 void list_domains_details(void)
 {
     struct libxl_dominfo *info;
+    struct domain_config d_config;
+
     char *config_file;
     uint8_t *data;
     int nb_domain, i, len, rc;

@@ -1917,7 +2052,7 @@ void list_domains_details(void)
         if (rc)
             continue;
         CHK_ERRNO(asprintf(&config_file, "<domid %d data>", info[i].domid));
-        parse_config_data(config_file, (char *)data, len, &c_info, &b_info, &disks, &num_disks, &vifs, &num_vifs, &vif2s, &num_vif2s, &pcidevs, &num_pcidevs, &vfbs, &num_vfbs, &vkbs, &num_vkbs, &dm_info);
+        parse_config_data(config_file, (char *)data, len, &c_info, &b_info, &d_config, &disks, &num_disks, &vifs, &num_vifs, &vif2s, &num_vif2s, &pcidevs, &num_pcidevs, &vfbs, &num_vfbs, &vkbs, &num_vkbs, &dm_info);
         printf_info(info[i].domid, &c_info, &b_info, disks, num_disks, vifs, num_vifs, pcidevs, num_pcidevs, vfbs, num_vfbs, vkbs, num_vkbs, &dm_info);
         free(data);
         free(config_file);

diff -r 1c1b0c8bb58c -r d9b5f51a54ca tools/libxl/libxl.c
@@ -399,6 +399,61 @@ int libxl_domain_resume(struct libxl_ctx
                         domid);
         return ERROR_FAIL;
     }
+    return 0;
+}
+
+/*
+ * Preserves a domain but rewrites xenstore etc to make it unique so
+ * that the domain can be restarted.
+ *
+ * Does not modify info so that it may be reused.
+ */
+int libxl_domain_preserve(struct libxl_ctx *ctx, uint32_t domid,
+                          libxl_domain_create_info *info, const char *name_suffix, uint8_t new_uuid[16])
+{
+    struct xs_permissions roperm[2];
+    xs_transaction_t t;
+    char *preserved_name;
+    char *uuid_string;
+    char *vm_path;
+    char *dom_path;
+
+    int rc;
+
+    preserved_name = libxl_sprintf(ctx, "%s%s", info->name, name_suffix);
+    if (!preserved_name) return ERROR_NOMEM;
+
+    uuid_string = libxl_uuid2string(ctx, new_uuid);
+    if (!uuid_string) return ERROR_NOMEM;
+
+    dom_path = libxl_xs_get_dompath(ctx, domid);
+    if (!dom_path) return ERROR_FAIL;
+
+    vm_path = libxl_sprintf(ctx, "/vm/%s", uuid_string);
+    if (!vm_path) return ERROR_FAIL;
+
+    roperm[0].id = 0;
+    roperm[0].perms = XS_PERM_NONE;
+    roperm[1].id = domid;
+    roperm[1].perms = XS_PERM_READ;
+
+ retry_transaction:
+    t = xs_transaction_start(ctx->xsh);
+
+    xs_rm(ctx->xsh, t, vm_path);
+    xs_mkdir(ctx->xsh, t, vm_path);
+    xs_set_permissions(ctx->xsh, t, vm_path, roperm, ARRAY_SIZE(roperm));
+
+    xs_write(ctx->xsh, t, libxl_sprintf(ctx, "%s/vm", dom_path), vm_path, strlen(vm_path));
+    rc = libxl_domain_rename(ctx, domid, info->name, preserved_name, t);
+    if (rc) return rc;
+
+    xs_write(ctx->xsh, t, libxl_sprintf(ctx, "%s/uuid", vm_path), uuid_string, strlen(uuid_string));
+
+    if (!xs_transaction_end(ctx->xsh, t, 0))
+        if (errno == EAGAIN)
+            goto retry_transaction;
+
     return 0;
 }
 

diff -r 1c1b0c8bb58c -r d9b5f51a54ca tools/libxl/libxl.h
@@ -338,6 +338,7 @@ int libxl_domain_resume(struct libxl_ctx
 int libxl_domain_resume(struct libxl_ctx *ctx, uint32_t domid);
 int libxl_domain_shutdown(struct libxl_ctx *ctx, uint32_t domid, int req);
 int libxl_domain_destroy(struct libxl_ctx *ctx, uint32_t domid, int force);
+int libxl_domain_preserve(struct libxl_ctx *ctx, uint32_t domid, libxl_domain_create_info *info, const char *name_suffix, uint8_t new_uuid[16]);
 
 int libxl_file_reference_map(struct libxl_ctx *ctx, libxl_file_reference *f);
 int libxl_file_reference_unmap(struct libxl_ctx *ctx, libxl_file_reference *f);

diff -r d9b5f51a54ca -r 519187e3e2b1 tools/libxl/xl_cmdimpl.c
@@ -104,6 +104,7 @@ enum action_on_shutdown {
     ACTION_DESTROY,
 
     ACTION_RESTART,
+    ACTION_RESTART_RENAME,
 
     ACTION_PRESERVE,
 

@@ -115,6 +116,7 @@ static char *action_on_shutdown_names[] 
     [ACTION_DESTROY] = "destroy",
 
     [ACTION_RESTART] = "restart",
+    [ACTION_RESTART_RENAME] = "rename-restart",
 
     [ACTION_PRESERVE] = "preserve",
 

@@ -1064,7 +1066,7 @@ int autoconnect_console(int hvm)
     _exit(1);
 }
 
-/* Returns 1 if domain should be restarted */
+/* Returns 1 if domain should be restarted, 2 if domain should be renamed then restarted  */
 static int handle_domain_death(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event,
                                libxl_domain_create_info *c_info,
                                struct domain_config *d_config, struct libxl_dominfo *info)

@@ -1112,6 +1114,10 @@ static int handle_domain_death(struct li
 
     switch (action) {
     case ACTION_PRESERVE:
+        break;
+
+    case ACTION_RESTART_RENAME:
+        restart = 2;
         break;
 
     case ACTION_RESTART:

@@ -1129,6 +1135,43 @@ static int handle_domain_death(struct li
     }
 
     return restart;
+}
+
+static int preserve_domain(struct libxl_ctx *ctx, uint32_t domid, libxl_event *event,
+                           libxl_domain_create_info *c_info,
+                           struct domain_config *d_config, struct libxl_dominfo *info)
+{
+    time_t now;
+    struct tm tm;
+    char stime[24];
+
+    uint8_t new_uuid[16];
+
+    int rc;
+
+    now = time(NULL);
+    if (now == ((time_t) -1)) {
+        LOG("Failed to get current time for domain rename");
+        return 0;
+    }
+
+    tzset();
+    if (gmtime_r(&now, &tm) == NULL) {
+        LOG("Failed to convert time to UTC");
+        return 0;
+    }
+
+    if (!strftime(&stime[0], sizeof(stime), "-%Y%m%dT%H%MZ", &tm)) {
+        LOG("Failed to format time as a string");
+        return 0;
+    }
+
+    random_uuid(&new_uuid[0]);
+
+    LOG("Preserving domain %d %s with suffix%s", domid, c_info->name, stime);
+    rc = libxl_domain_preserve(ctx, domid, c_info, stime, new_uuid);
+
+    return rc == 0 ? 1 : 0;
 }
 
 struct domain_create {

@@ -1502,7 +1545,15 @@ start:
                 LOG("Domain %d is dead", domid);
 
                 if (ret) {
-                    if (handle_domain_death(&ctx, domid, &event, &c_info, &d_config, &info)) {
+                    switch (handle_domain_death(&ctx, domid, &event, &c_info, &d_config, &info)) {
+                    case 2:
+                        if (!preserve_domain(&ctx, domid, &event, &c_info, &d_config, &info))
+                            /* If we fail then exit leaving the old domain in place. */
+                            exit(-1);
+
+                        /* Otherwise fall through and restart. */
+                    case 1:
+
                         libxl_free_waiter(w1);
                         libxl_free_waiter(w2);
                         free(w1);

@@ -1514,9 +1565,10 @@ start:
                         LOG("Done. Rebooting now");
                         sleep(2);
                         goto start;
+                    case 0:
+                        LOG("Done. Exiting now");
+                        exit(0);
                     }
-                    LOG("Done. Exiting now");
-                    exit(0);
                 }
                 break;
             case LIBXL_EVENT_DISK_EJECT: