[Xen-devel] [PATCH] libxl, Introduce a QMP client

[<anthony.perard@xxxxxxxxxx>]

From: Anthony PERARD <anthony.perard@xxxxxxxxxx>

QMP stands for QEMU Monitor Protocol and it is used to query information
from QEMU or to control QEMU.

This implementation will ask QEMU the list of chardevice and store the
path to serial0 in xenstored. So we will be able to use xl console with
QEMU upstream.

In order to connect to the QMP server, a socket file is created in
/var/run/xen/qmp-$(domid).

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 tools/libxl/Makefile     |    4 +
 tools/libxl/libxl_dm.c   |    5 +
 tools/libxl/libxl_qmp.c  |  864 ++++++++++++++++++++++++++++++++++++++++++++++
 tools/libxl/libxl_qmp.h  |   25 ++
 tools/libxl/xl_cmdimpl.c |   29 ++-
 5 files changed, 926 insertions(+), 1 deletions(-)
 create mode 100644 tools/libxl/libxl_qmp.c
 create mode 100644 tools/libxl/libxl_qmp.h

diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
index 538cd16..7da5e59 100644
--- a/tools/libxl/Makefile
+++ b/tools/libxl/Makefile
@@ -32,6 +32,9 @@ endif
 LIBXL_OBJS-$(CONFIG_X86) += libxl_cpuid.o
 LIBXL_OBJS-$(CONFIG_IA64) += libxl_nocpuid.o
 
+LIBXL_OBJS-y += libxl_qmp.o
+LIBXL_LIBS += -lyajl
+
 LIBXL_OBJS = flexarray.o libxl.o libxl_create.o libxl_dm.o libxl_pci.o \
                        libxl_dom.o libxl_exec.o libxl_xshelp.o libxl_device.o \
                        libxl_internal.o libxl_utils.o libxl_uuid.o 
$(LIBXL_OBJS-y)
@@ -115,6 +118,7 @@ install: all
        $(INSTALL_DIR) $(DESTDIR)$(LIBDIR)
        $(INSTALL_DIR) $(DESTDIR)$(INCLUDEDIR)
        $(INSTALL_DIR) $(DESTDIR)$(BASH_COMPLETION_DIR)
+       $(INSTALL_DIR) $(DESTDIR)/var/run/xen
        $(INSTALL_PROG) xl $(DESTDIR)$(SBINDIR)
        $(INSTALL_PROG) libxenlight.so.$(MAJOR).$(MINOR) $(DESTDIR)$(LIBDIR)
        ln -sf libxenlight.so.$(MAJOR).$(MINOR) 
$(DESTDIR)$(LIBDIR)/libxenlight.so.$(MAJOR)
diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 47a51c8..a7ff750 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -245,6 +245,11 @@ static char ** 
libxl__build_device_model_args_new(libxl__gc *gc,
     flexarray_vappend(dm_args, dm,
                       "-xen-domid", libxl__sprintf(gc, "%d", info->domid), 
NULL);
 
+    flexarray_append(dm_args, "-qmp");
+    flexarray_append(dm_args,
+                     libxl__sprintf(gc, 
"unix:/var/run/xen/qmp-%d,server,nowait",
+                                    info->domid));
+
     if (info->type == LIBXL_DOMAIN_TYPE_PV) {
         flexarray_append(dm_args, "-xen-attach");
     }
diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c
new file mode 100644
index 0000000..6cd1a74
--- /dev/null
+++ b/tools/libxl/libxl_qmp.c
@@ -0,0 +1,864 @@
+/*
+ * Copyright (C) 2011      Citrix Ltd.
+ * Author Anthony PERARD <anthony.perard@xxxxxxxxxx>
+ *
+ * This program 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; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * This program 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.
+ */
+
+/*
+ * This file implement a client for QMP (QEMU Monitor Protocol). For the
+ * Specification, see in the QEMU repository.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/un.h>
+#include <sys/queue.h>
+
+#include <yajl/yajl_parse.h>
+#include <yajl/yajl_gen.h>
+
+#include "libxl_internal.h"
+#include "flexarray.h"
+#include "libxl_qmp.h"
+
+/* #define DEBUG_ANSWER */
+/* #define DEBUG_RECEIVE */
+
+/*
+ * json_object types
+ */
+
+typedef struct json_object json_object;
+typedef struct json_map_node json_map_node;
+typedef enum node_type node_type_e;
+
+enum node_type {
+    JSON_ERROR,
+    JSON_NULL,
+    JSON_BOOL,
+    JSON_INTEGER,
+    JSON_DOUBLE,
+    JSON_STRING,
+    JSON_MAP,
+    JSON_ARRAY
+};
+
+struct json_object {
+    node_type_e type;
+    union {
+        bool boolean;
+        long integer;
+        double floating;
+        const char *string;
+        /* List of json_object */
+        flexarray_t *array;
+        /* List of json_map_node */
+        flexarray_t *map;
+    } u;
+    json_object *parent;
+};
+
+struct json_map_node {
+    const char *map_key;
+    json_object *obj;
+};
+
+/*
+ * QMP types & constant
+ */
+
+typedef int (*qmp_callback_t)(libxl_qmp_handler *qmp, const json_object *tree);
+
+typedef enum message_type {
+    QMP_ANY,
+    QMP_QMP,
+    QMP_RETURN,
+    QMP_ERROR,
+    QMP_EVENT
+} message_type_e;
+
+struct {
+    const char *name;
+    message_type_e type;
+} member_name_to_message_type[] = {
+    { "QMP", QMP_QMP },
+    { "return", QMP_RETURN },
+    { "error", QMP_ERROR },
+    { "event", QMP_EVENT },
+    { "", QMP_ANY },
+};
+
+typedef struct callback_id_pair {
+    int id;
+    qmp_callback_t callback;
+    SIMPLEQ_ENTRY(callback_id_pair) next;
+} callback_id_pair;
+
+struct libxl_qmp_handler {
+    struct sockaddr_un addr;
+    int qmp_fd;
+
+    unsigned char *buffer;
+    yajl_handle hand;
+
+    json_object *head;
+    json_object *current;
+
+    libxl_ctx *ctx;
+    uint32_t domid;
+
+    int last_id_used;
+    SIMPLEQ_HEAD(callback_list, callback_id_pair) callback_list;
+#ifdef DEBUG_ANSWER
+    yajl_gen g;
+#endif
+};
+
+static int qmp_send(libxl_qmp_handler *qmp, const char *cmd, qmp_callback_t 
callback);
+
+static const size_t QMP_RECEIVE_BUFFER_SIZE = 65536;
+
+/*
+ * json_object functions
+ */
+
+static int json_object_append_to(libxl_qmp_handler *qmp, json_object *obj, 
json_object *dst)
+{
+    if (!dst)
+        return -1;
+
+    switch (dst->type) {
+    case JSON_MAP: {
+        json_map_node *last;
+
+        flexarray_get(dst->u.map, dst->u.map->count - 1, (void**)&last);
+        last->obj = obj;
+        break;
+    }
+    case JSON_ARRAY:
+        flexarray_append(dst->u.array, obj);
+        break;
+    default:
+        LIBXL__LOG(qmp->ctx, LIBXL__LOG_ERROR,
+                   "error, try append an object to a %i\n", dst->type);
+        return -1;
+    }
+
+    obj->parent = dst;
+    return 0;
+}
+
+static void json_object_free(libxl_qmp_handler *qmp, json_object *obj)
+{
+    int index = 0;
+
+    if (obj == NULL)
+        return;
+    switch (obj->type) {
+    case JSON_ERROR:
+    case JSON_NULL:
+    case JSON_BOOL:
+    case JSON_INTEGER:
+    case JSON_DOUBLE:
+        break;
+    case JSON_STRING:
+        free((void*)obj->u.string);
+        break;
+    case JSON_MAP: {
+        json_map_node *node = NULL;
+
+        for (index = 0; index < obj->u.map->count; index++) {
+            if (flexarray_get(obj->u.map, index, (void**)&node) != 0)
+                break;
+            json_object_free(qmp, node->obj);
+            free((void*)node->map_key);
+            free(node);
+            node = NULL;
+        }
+        flexarray_free(obj->u.map);
+        break;
+    }
+    case JSON_ARRAY:{
+        json_object *node = NULL;
+        break;
+
+        for (index = 0; index < obj->u.array->count; index++) {
+            if (flexarray_get(obj->u.array, index, (void**)&node) != 0)
+                break;
+            json_object_free(qmp, node);
+            node = NULL;
+        }
+        flexarray_free(obj->u.array);
+        break;
+    }
+    }
+    free(obj);
+}
+
+static inline const char *json_object_get_string(const json_object *o)
+{
+    if (o && o->type == JSON_STRING) {
+        return o->u.string;
+    }
+    return NULL;
+}
+
+static const json_object *json_object_map_get(const char *key, const 
json_object *o)
+{
+    flexarray_t *maps = NULL;
+    int index = 0;
+
+    if (o && o->type == JSON_MAP) {
+        json_map_node *node = NULL;
+
+        maps = o->u.map;
+        for (index = 0; index < maps->count; index++) {
+            if (flexarray_get(maps, index, (void**)&node) != 0)
+                break;
+            if (strcmp(key, node->map_key) == 0) {
+                return node->obj;
+            }
+        }
+    }
+    return NULL;
+}
+
+/*
+ * JSON callbacks
+ */
+
+static int json_callback_null(void *opaque)
+{
+    libxl_qmp_handler *qmp = opaque;
+    json_object *obj;
+
+#ifdef DEBUG_ANSWER
+    yajl_gen_null(qmp->g);
+#endif
+
+    obj = calloc(1, sizeof (json_object));
+    obj->type = JSON_NULL;
+    json_object_append_to(qmp, obj, qmp->current);
+
+    return 1;
+}
+
+static int json_callback_boolean(void *opaque, int boolean)
+{
+    libxl_qmp_handler *qmp = opaque;
+    json_object *obj;
+
+#ifdef DEBUG_ANSWER
+    yajl_gen_bool(qmp->g, boolean);
+#endif
+
+    obj = calloc(1, sizeof (json_object));
+    obj->type = JSON_BOOL;
+    obj->u.boolean = boolean;
+    json_object_append_to(qmp, obj, qmp->current);
+
+    return 1;
+}
+
+static int json_callback_integer(void *opaque, long value)
+{
+    libxl_qmp_handler *qmp = opaque;
+    json_object *obj;
+
+#ifdef DEBUG_ANSWER
+    yajl_gen_integer(qmp->g, value);
+#endif
+
+    obj = calloc(1, sizeof (json_object));
+    obj->type = JSON_INTEGER;
+    obj->u.integer = value;
+    json_object_append_to(qmp, obj, qmp->current);
+
+    return 1;
+}
+
+static int json_callback_double(void *opaque, double value)
+{
+    libxl_qmp_handler *qmp = opaque;
+    json_object *obj;
+
+#ifdef DEBUG_ANSWER
+    yajl_gen_double(qmp->g, value);
+#endif
+
+    obj = calloc(1, sizeof (json_object));
+    obj->type = JSON_DOUBLE;
+    obj->u.floating = value;
+    json_object_append_to(qmp, obj, qmp->current);
+
+    return 1;
+}
+
+static int json_callback_string(void *opaque, const unsigned char *str,
+                           unsigned int len)
+{
+    libxl_qmp_handler *qmp = opaque;
+    char *t = malloc(len + 1);
+    json_object *obj = NULL;
+
+#ifdef DEBUG_ANSWER
+    yajl_gen_string(qmp->g, str, len);
+#endif
+
+    strncpy(t, (const char *) str, len);
+    t[len] = 0;
+
+    obj = calloc(1, sizeof (json_object));
+    obj->type = JSON_STRING;
+    obj->u.string = t;
+
+    json_object_append_to(qmp, obj, qmp->current);
+
+    return 1;
+}
+
+static int json_callback_map_key(void *opaque, const unsigned char *str,
+                            unsigned int len)
+{
+    libxl_qmp_handler *qmp = opaque;
+    char *t = malloc(len + 1);
+    json_object *obj = qmp->current;
+
+#ifdef DEBUG_ANSWER
+    yajl_gen_string(qmp->g, str, len);
+#endif
+
+    strncpy(t, (const char *) str, len);
+    t[len] = 0;
+
+    if (obj->type == JSON_MAP) {
+        json_map_node *node = malloc(sizeof (json_map_node));
+
+        node->map_key = t;
+        node->obj = NULL;
+
+        flexarray_append(obj->u.map, node);
+    } else {
+        return 0;
+    }
+
+    return 1;
+}
+
+static int json_callback_start_map(void *opaque)
+{
+    libxl_qmp_handler *qmp = opaque;
+    json_object *obj = NULL;
+
+#ifdef DEBUG_ANSWER
+    yajl_gen_map_open(qmp->g);
+#endif
+
+    obj = calloc(1, sizeof (json_object));
+    if (qmp->head == NULL) {
+        qmp->head = obj;
+    }
+
+    obj->type = JSON_MAP;
+    obj->u.map = flexarray_make(1, 1);
+
+    json_object_append_to(qmp, obj, qmp->current);
+
+    obj->parent = qmp->current;
+    qmp->current = obj;
+
+    return 1;
+}
+
+static int json_callback_end_map(void *opaque)
+{
+    libxl_qmp_handler *qmp = opaque;
+
+#ifdef DEBUG_ANSWER
+    yajl_gen_map_close(qmp->g);
+#endif
+
+    if (qmp->current) {
+        qmp->current = qmp->current->parent;
+    } else {
+        LIBXL__LOG(qmp->ctx, LIBXL__LOG_ERROR, "no parents for a json_object");
+        return 0;
+    }
+
+    return 1;
+}
+
+static int json_callback_start_array(void *opaque)
+{
+    libxl_qmp_handler *qmp = opaque;
+    json_object *obj = NULL;
+
+#ifdef DEBUG_ANSWER
+    yajl_gen_array_open(qmp->g);
+#endif
+
+    obj = calloc(1, sizeof (json_object));
+    if (qmp->head == NULL) {
+        qmp->head = obj;
+    }
+    obj->type = JSON_ARRAY;
+    obj->u.array = flexarray_make(1, 1);
+    json_object_append_to(qmp, obj, qmp->current);
+    qmp->current = obj;
+
+    return 1;
+}
+
+static int json_callback_end_array(void *opaque)
+{
+    libxl_qmp_handler *qmp = opaque;
+
+#ifdef DEBUG_ANSWER
+    yajl_gen_array_close(qmp->g);
+#endif
+
+    if (qmp->current) {
+        qmp->current = qmp->current->parent;
+    } else {
+        LIBXL__LOG(qmp->ctx, LIBXL__LOG_ERROR, "no parents for a json_object");
+        return 0;
+    }
+
+    return 1;
+}
+
+static yajl_callbacks callbacks = {
+    json_callback_null,
+    json_callback_boolean,
+    json_callback_integer,
+    json_callback_double,
+    NULL,
+    json_callback_string,
+    json_callback_start_map,
+    json_callback_map_key,
+    json_callback_end_map,
+    json_callback_start_array,
+    json_callback_end_array
+};
+
+/*
+ * QMP callbacks functions
+ */
+
+static const char *get_serial0_chardev(libxl_qmp_handler *qmp, const 
json_object *tree)
+{
+    const json_object *ret = NULL;
+    const json_object *obj = NULL;
+    const json_object *label = NULL;
+    const char *s = NULL;
+    flexarray_t *array = NULL;
+    int index = 0;
+
+    ret = json_object_map_get("return", tree);
+
+    if (!ret || ret->type != JSON_ARRAY) {
+        return NULL;
+    }
+    array = ret->u.array;
+    for (index = 0; index < array->count; index++) {
+        if (flexarray_get(array, index, (void**)&obj) != 0)
+            break;
+        label = json_object_map_get("label", obj);
+        s = json_object_get_string(label);
+
+        /* TODO Could replace serial0 by serial and get all serial ttys, if 
sevral */
+        if (s && strcmp("serial0", s) == 0) {
+            const json_object *filename = NULL;
+            filename = json_object_map_get("filename", obj);
+            return json_object_get_string(filename);
+        }
+    };
+
+    return NULL;
+}
+
+static int register_serial0_chardev_callback(libxl_qmp_handler *qmp, const 
json_object *tree)
+{
+    libxl__gc gc = LIBXL_INIT_GC(qmp->ctx);
+    char *path = NULL;
+    const char *chardev = NULL;
+    int ret = 0;
+
+    chardev = get_serial0_chardev(qmp, tree);
+    if (!(chardev && strncmp("pty:", chardev, 4) == 0)) {
+        return 1;
+    }
+
+    path = libxl__xs_get_dompath(&gc, qmp->domid);
+    path = libxl__sprintf(&gc, "%s/serial/%d/tty", path, 0);
+
+    LIBXL__LOG(qmp->ctx, LIBXL__LOG_DEBUG,
+               "qmp serial0: %s (%s)", chardev + 4, path);
+    ret = libxl__xs_write(&gc, XBT_NULL, path, "%s", chardev + 4);
+    libxl__free_all(&gc);
+    return ret;
+}
+
+static int qmp_capabilities_callback(libxl_qmp_handler *qmp, const json_object 
*tree)
+{
+    /* The purpuse of this function is to ask to QEMU every information needed
+     * by xl. */
+    int ret = 0;
+
+    ret = qmp_send(qmp, "query-chardev", register_serial0_chardev_callback);
+
+    return ret;
+}
+
+/*
+ * QMP commands
+ */
+
+static int enable_qmp_capabilities(libxl_qmp_handler *qmp)
+{
+    return qmp_send(qmp, "qmp_capabilities", qmp_capabilities_callback);
+}
+
+/*
+ * Helpers
+ */
+
+static message_type_e qmp_response_type(libxl_qmp_handler *qmp, json_object 
*resp)
+{
+    if (resp && resp->type == JSON_MAP) {
+        flexarray_t *maps = NULL;
+        json_map_node *node = NULL;
+        int index = 0;
+
+        maps = resp->u.map;
+        for (index = 0; index < maps->count; index++) {
+            int i = 0;
+            if (flexarray_get(maps, index, (void**)&node) != 0)
+                break;
+            for (i = 0; member_name_to_message_type[i].type != QMP_ANY; i++) {
+                if (strcmp(member_name_to_message_type[i].name, node->map_key) 
== 0) {
+                    return member_name_to_message_type[i].type;
+                }
+            }
+        }
+    }
+
+    return QMP_ANY;
+}
+
+static callback_id_pair *qmp_get_callback_from_id(libxl_qmp_handler *qmp, 
json_object *o)
+{
+    const json_object *id_object = json_object_map_get("id", o);
+    int id = -1;
+    callback_id_pair *pp = NULL;
+
+    if (id_object && id_object->type == JSON_INTEGER) {
+        id = id_object->u.integer;
+
+        SIMPLEQ_FOREACH(pp, &qmp->callback_list, next) {
+            if (pp->id == id) {
+                return pp;
+            }
+        }
+    }
+    return NULL;
+}
+
+static void qmp_handle_error_response(libxl_qmp_handler *qmp, json_object 
*resp)
+{
+    callback_id_pair *pp = qmp_get_callback_from_id(qmp, resp);
+    const json_object *error = json_object_map_get("error", resp);
+    const char *msg = json_object_get_string(json_object_map_get("desc", 
error));
+
+    if (pp) {
+        SIMPLEQ_REMOVE(&qmp->callback_list, pp, callback_id_pair, next);
+        free(pp);
+    }
+
+    LIBXL__LOG(qmp->ctx, LIBXL__LOG_ERROR,
+               "receive an error message from QMP server: %s",
+               msg);
+}
+
+static int qmp_handle_response(libxl_qmp_handler *qmp, json_object *resp)
+{
+    message_type_e type = QMP_ANY;
+
+    type = qmp_response_type(qmp, resp);
+    LIBXL__LOG(qmp->ctx, LIBXL__LOG_DEBUG, "message type: %i", type);
+
+    switch (type) {
+    case QMP_QMP:
+        /* On the greeting message from the server, enable qmp capabilities */
+        enable_qmp_capabilities(qmp);
+        break;
+    case QMP_RETURN: {
+        callback_id_pair *pp = qmp_get_callback_from_id(qmp, resp);
+
+        if (pp) {
+            pp->callback(qmp, resp);
+            SIMPLEQ_REMOVE(&qmp->callback_list, pp, callback_id_pair, next);
+            free(pp);
+        }
+        break;
+    }
+    case QMP_ERROR:
+        qmp_handle_error_response(qmp, resp);
+        break;
+    case QMP_EVENT:
+        break;
+    case QMP_ANY:
+        return -1;
+    }
+    return 0;
+}
+
+/*
+ * Handler functions
+ */
+
+static int qmp_connect(libxl_qmp_handler *qmp, const char *qmp_socket_path,
+                       int timeout)
+{
+    int ret;
+    int i = 0;
+
+    qmp->qmp_fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0);
+    if (qmp->qmp_fd < 0) {
+        return -1;
+    }
+
+    memset(&qmp->addr, 0, sizeof (&qmp->addr));
+    qmp->addr.sun_family = AF_UNIX;
+    strncpy(qmp->addr.sun_path, qmp_socket_path, sizeof (qmp->addr.sun_path));
+
+    do {
+        ret = connect(qmp->qmp_fd, (struct sockaddr *) &qmp->addr,
+                      sizeof (qmp->addr));
+        if (ret == 0)
+            break;
+        if (errno == ENOENT || errno == ECONNREFUSED) {
+            /* ENOENT       : Socket may not have shown up yet
+             * ECONNREFUSED : Leftover socket hasn't been removed yet */
+            continue;
+        }
+        return -1;
+    } while ((++i <= timeout * 5) && (usleep(.2 * 1000000) <= 0));
+
+    if (ret == -1)
+        return -1;
+
+    return 0;
+}
+
+static void qmp_close(libxl_qmp_handler *qmp)
+{
+    callback_id_pair *pp = NULL;
+    callback_id_pair *tmp = NULL;
+#ifdef DEBUG_ANSWER
+    if (qmp->g)
+        yajl_gen_free(qmp->g);
+#endif
+    if (qmp->hand)
+        yajl_free(qmp->hand);
+    close(qmp->qmp_fd);
+    unlink(qmp->addr.sun_path);
+    SIMPLEQ_FOREACH(pp, &qmp->callback_list, next) {
+        if (tmp)
+            free(tmp);
+        tmp = pp;
+    }
+    if (tmp)
+        free(tmp);
+}
+
+static int qmp_next(libxl_qmp_handler *qmp)
+{
+    yajl_status status;
+    ssize_t rd;
+    ssize_t bytes_parsed = 0;
+
+    /* read the socket */
+    rd = read(qmp->qmp_fd, qmp->buffer, QMP_RECEIVE_BUFFER_SIZE);
+    if (rd <= 0) {
+        /* either an error, or nothing */
+        return rd;
+    }
+#ifdef DEBUG_RECEIVE
+    qmp->buffer[rd] = 0;
+    LIBXL__LOG(qmp->ctx, LIBXL__LOG_DEBUG, "received: '%s'", qmp->buffer);
+#endif
+
+    while (bytes_parsed < rd) {
+#ifdef DEBUG_ANSWER
+        if (qmp->g == NULL) {
+            yajl_gen_config conf = { 1, "  " };
+            qmp->g = yajl_gen_alloc(&conf, NULL);
+        }
+#endif
+        /* parse the input */
+        if (qmp->hand == NULL) {
+            /* allow comments */
+            yajl_parser_config cfg = { 1, 1 };
+            qmp->hand = yajl_alloc(&callbacks, &cfg, NULL, qmp);
+        }
+        status = yajl_parse(qmp->hand, qmp->buffer + bytes_parsed, rd - 
bytes_parsed);
+        bytes_parsed += yajl_get_bytes_consumed(qmp->hand);
+
+        /* handle the answer */
+        if (status != yajl_status_ok && status != 
yajl_status_insufficient_data) {
+            unsigned char *str = yajl_get_error(qmp->hand, 1, qmp->buffer, rd);
+
+            LIBXL__LOG(qmp->ctx, LIBXL__LOG_ERROR, "yajl error: %s", str);
+            yajl_free_error(qmp->hand, str);
+        }
+
+        if (status == yajl_status_ok) {
+#ifdef DEBUG_ANSWER
+            const unsigned char *buf = NULL;
+            unsigned int len = 0;
+
+            yajl_gen_get_buf(qmp->g, &buf, &len);
+            LIBXL__LOG(qmp->ctx, LIBXL__LOG_DEBUG, "response:\n%s", buf);
+            yajl_gen_free(qmp->g);
+            qmp->g = NULL;
+#endif
+
+            qmp_handle_response(qmp, qmp->head);
+
+            json_object_free(qmp, qmp->head);
+            qmp->head = NULL;
+            qmp->current = NULL;
+
+            yajl_free(qmp->hand);
+            qmp->hand = NULL;
+        }
+        /* skip the CRLF of the end of a command */
+        while (bytes_parsed < rd && (qmp->buffer[bytes_parsed] == '\r'
+                                     || qmp->buffer[bytes_parsed] == '\n')) {
+               bytes_parsed++;
+        }
+    }
+    return 1;
+}
+
+static int qmp_send(libxl_qmp_handler *qmp, const char *cmd, qmp_callback_t 
callback)
+{
+    yajl_gen_config conf = { 0, NULL };
+    const unsigned char *buf;
+    const char *ex = "execute";
+    unsigned int len = 0;
+    yajl_gen_status s;
+    yajl_gen hand;
+
+    hand = yajl_gen_alloc(&conf, NULL);
+    if (!hand) {
+        return -1;
+    }
+
+    yajl_gen_map_open(hand);
+    yajl_gen_string(hand, (const unsigned char *)ex, strlen(ex));
+    yajl_gen_string(hand, (const unsigned char *)cmd, strlen(cmd));
+    yajl_gen_string(hand, (const unsigned char *)"id", 2);
+    yajl_gen_integer(hand, ++qmp->last_id_used);
+    yajl_gen_map_close(hand);
+
+    s = yajl_gen_get_buf(hand, &buf, &len);
+
+    if (s) {
+        LIBXL__LOG(qmp->ctx, LIBXL__LOG_ERROR,
+                   "could not generate a qmp command");
+        return -1;
+    }
+
+    if (callback) {
+        callback_id_pair *elm = malloc(sizeof (callback_id_pair));
+        elm->id = qmp->last_id_used;
+        elm->callback = callback;
+        SIMPLEQ_INSERT_TAIL(&qmp->callback_list, elm, next);
+    }
+
+    LIBXL__LOG(qmp->ctx, LIBXL__LOG_DEBUG, "next qmp command: '%s'", buf);
+
+    write(qmp->qmp_fd, buf, len);
+    write(qmp->qmp_fd, "\r\n", 2);
+    yajl_gen_free(hand);
+
+    return 0;
+}
+
+/*
+ * API
+ */
+
+libxl_qmp_handler *libxl_qmp_initialize(libxl_ctx *ctx, const char 
*qmp_socket, uint32_t domid)
+{
+    int ret = 0;
+    libxl_qmp_handler *qmp = NULL;
+
+    qmp = calloc(1, sizeof (libxl_qmp_handler));
+    qmp->ctx = ctx;
+    qmp->domid = domid;
+    if ((qmp->buffer = malloc(QMP_RECEIVE_BUFFER_SIZE)) == NULL) {
+        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "Can not allocate the 
reception buffer");
+        free(qmp);
+        return NULL;
+    }
+
+
+    if ((ret = qmp_connect(qmp, qmp_socket, 5)) < 0) {
+        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "Connection error");
+        free(qmp->buffer);
+        free(qmp);
+        return NULL;
+    }
+
+    SIMPLEQ_INIT(&qmp->callback_list);
+
+    LIBXL__LOG(qmp->ctx, LIBXL__LOG_DEBUG, "connected to %s", qmp_socket);
+
+    return qmp;
+}
+
+int libxl_qmp_get_fd(libxl_qmp_handler *qmp)
+{
+    if (qmp)
+        return qmp->qmp_fd;
+    else
+        return -1;
+}
+
+int libxl_qmp_do_next(libxl_qmp_handler *qmp)
+{
+    int ret;
+
+    if (!qmp)
+        return -1;
+    ret = qmp_next(qmp);
+    if (ret < 0) {
+        LIBXL__LOG_ERRNO(qmp->ctx, LIBXL__LOG_ERROR, "QMP, read error");
+    }
+
+    return ret;
+}
+
+void libxl_qmp_close(libxl_qmp_handler *qmp)
+{
+    if (!qmp)
+        return;
+    qmp_close(qmp);
+    free(qmp->buffer);
+    free(qmp);
+}
diff --git a/tools/libxl/libxl_qmp.h b/tools/libxl/libxl_qmp.h
new file mode 100644
index 0000000..efac9b8
--- /dev/null
+++ b/tools/libxl/libxl_qmp.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2011      Citrix Ltd.
+ * Author Anthony PERARD <anthony.perard@xxxxxxxxxx>
+ *
+ * This program 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; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * This program 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.
+ */
+
+#include "libxl.h"
+
+typedef struct libxl_qmp_handler libxl_qmp_handler;
+
+libxl_qmp_handler *libxl_qmp_initialize(libxl_ctx *ctx,
+                                        const char *qmp_socket,
+                                        uint32_t domid);
+int libxl_qmp_get_fd(libxl_qmp_handler *qmp);
+int libxl_qmp_do_next(libxl_qmp_handler *qmp);
+void libxl_qmp_close(libxl_qmp_handler *qmp);
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 5415bc5..6df56f6 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -39,6 +39,7 @@
 #include "libxl.h"
 #include "libxl_utils.h"
 #include "libxlutil.h"
+#include "libxl_qmp.h"
 #include "xl.h"
 
 #define CHK_ERRNO( call ) ({                                            \
@@ -1367,6 +1368,9 @@ static int create_domain(struct domain_create *dom_info)
     pid_t child_console_pid = -1;
     struct save_file_header hdr;
 
+    libxl_qmp_handler *qmp_handler = NULL;
+    int qmp_fd = -1;
+
     memset(&d_config, 0x00, sizeof(d_config));
 
     if (restore_file) {
@@ -1606,6 +1610,19 @@ start:
     libxl_wait_for_disk_ejects(ctx, domid, d_config.disks, d_config.num_disks, 
w1);
     libxl_wait_for_domain_death(ctx, domid, w2);
     libxl_get_wait_fd(ctx, &fd);
+    if (d_config.dm_info.device_model_version == 
LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
+        char socket[40];
+        snprintf(socket, sizeof (socket), "/var/run/xen/qmp-%d", domid);
+        LOG("Try initialize QMP connection, path: %s", socket);
+        qmp_handler = libxl_qmp_initialize(ctx, socket, domid);
+        if (qmp_handler) {
+            qmp_fd = libxl_qmp_get_fd(qmp_handler);
+        } else {
+            LOG("Could not connect to the QMP socket.");
+            qmp_fd = -1;
+        }
+    }
+
     while (1) {
         int ret;
         fd_set rfds;
@@ -1615,10 +1632,12 @@ start:
 
         FD_ZERO(&rfds);
         FD_SET(fd, &rfds);
+        FD_SET(qmp_fd, &rfds);
 
-        ret = select(fd + 1, &rfds, NULL, NULL, NULL);
+        ret = select(fd > qmp_fd ? fd + 1 : qmp_fd + 1, &rfds, NULL, NULL, 
NULL);
         if (!ret)
             continue;
+        if (FD_ISSET(fd, &rfds)) {
         libxl_get_event(ctx, &event);
         switch (event.type) {
             case LIBXL_EVENT_TYPE_DOMAIN_DEATH:
@@ -1687,6 +1706,10 @@ start:
                 break;
         }
         libxl_free_event(&event);
+        }
+        if (FD_ISSET(qmp_fd, &rfds)) {
+            libxl_qmp_do_next(qmp_handler);
+        }
     }
 
 error_out:
@@ -1697,6 +1720,10 @@ error_out:
 out:
     if (logfile != 2)
         close(logfile);
+    if (qmp_handler) {
+        libxl_qmp_close(qmp_handler);
+        qmp_handler = NULL;
+    }
 
     libxl_domain_config_destroy(&d_config);
 
-- 
1.7.2.5


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