4.3. D-Bus系列之获取发送者UID及PID的方法

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4.3.1. 获取PID及UID的原理

org.freedesktop.DBus提供了一系列的消息，其中就有根据服务名获取进程PID及UID的接口"org.freedesktop.DBus", --服务"/org/freedesktop/DBus", --对象"org.freedesktop.DBus", --接口"GetConnectionUnixProcessID", --方法 UINT32 GetConnectionUnixProcessID (in STRING bus_name);"GetConnectionUnixUser", --方法UINT32 GetConnectionUnixUser (in STRING bus_name);

4.3.2. QT DBUS获取的方法及示例

QT DBUS提供了相关调用的封装:

const QDBusMessage & QDBusContext::message () const Returns the message that generated this call.
QString QDBusMessage::service () const Returns the name of the service or the bus address of the remote method call.
QDBusReply QDBusConnectionInterface::servicePid ( const QString & serviceName ) const Returns the Unix Process ID (PID) for the process currently holding the bus service serviceName.

例如：

bool SomeMethod( const QString &name ){     qDebug() << "PID is: " << connection().interface()->servicePid( message().service() );}

4.3.3. D-Bus glib绑定及GDBus

D-Bus Glib 的绑定提供了获取发送者名字的方法：

const char *dbus_message_get_sender(DBusMessage *message);

但是没有提供获取进程PID及UID的方法，需自己编写代码调用GetConnectionUnixProcessID 和GetConnectionUnixUser方法。好像GDbus也没有提供，只找到了g_dbus_message_get_sender()方法。

/* proxy for getting PID info */g_dbus_proxy_new_for_bus(G_BUS_TYPE_SYSTEM,    G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES,    NULL,    "org.freedesktop.DBus",    "/org/freedesktop/DBus",    "org.freedesktop.DBus",    NULL,    (GAsyncReadyCallback)dbus_proxy_connect_cb,    NULL);voiddbus_proxy_connect_cb(GObject *source_object,               GAsyncResult *res,               gpointer user_data){    GError *error = NULL;    dbus_proxy = g_dbus_proxy_new_finish (res, &error);    if (error) {        g_warning("dbus_proxy_connect_cb failed: %s", error->message);        g_error_free(error);        dbus_proxy = NULL;    }    else {        g_debug("dbus_proxy_connect_cb succeeded");    }}gbooleanhandle_request_sys_state (PowerdSource *obj, GDBusMethodInvocation     *invocation, int state){    // get the name of the dbus object that called us    owner = g_dbus_method_invocation_get_sender(invocation);    if (dbus_proxy) {        result = g_dbus_proxy_call_sync(dbus_proxy,                "GetConnectionUnixProcessID",                g_variant_new("(s)", owner),                G_DBUS_CALL_FLAGS_NONE,                -1,                NULL,                &error);        if (error) {            g_error("Unable to get PID for %s: %s", owner, error->message);            g_error_free(error);            error = NULL;        }        else {            g_variant_get(result, "(u)", &owner_pid);            g_info("request is from pid %d\n", owner_pid);        }    }    ...}

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