root/jack2/branches/control/linux/dbus/jackdbus.c

/* -*- Mode: C ; c-basic-offset: 4 -*- */
/*
    Copyright (C) 2007,2008 Nedko Arnaudov
    Copyright (C) 2007-2008 Juuso Alasuutari
    
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <signal.h>
#include <dbus/dbus.h>
#include <pthread.h>
#include <unistd.h>

#include "jackdbus.h"
#include "controller.h"
#include "common/JackConstants.h"
#include "jack/jack.h"
#include "jack/jslist.h"
#include "jack/control.h"

FILE *g_logfile;
char *g_jackdbus_dir;
size_t g_jackdbus_dir_len; /* without terminating '\0' char */
int g_exit_command;
DBusConnection *g_connection;

void
jack_dbus_send_signal(
    const char *sender_object_path,
    const char *iface,
    const char *signal_name,
    int first_arg_type,
    ...)
{
    DBusMessage *message_ptr;
    va_list ap;

    va_start(ap, first_arg_type);

    message_ptr = dbus_message_new_signal(sender_object_path, iface, signal_name);
    if (message_ptr == NULL)
    {
        jack_error("dbus_message_new_signal() failed.");
        goto exit;
    }

    if (!dbus_message_append_args_valist(message_ptr, first_arg_type, ap))
    {
        jack_error("dbus_message_append_args_valist() failed.");
        goto unref;
    }

    /* Add message to outgoing message queue */
    if (!dbus_connection_send(g_connection, message_ptr, NULL))
    {
        jack_error("dbus_connection_send() failed.");
        goto unref;
    }

unref:
    dbus_message_unref(message_ptr);

exit:
    va_end(ap);
}

/*
 * Send a method return.
 *
 * If call->reply is NULL (i.e. a message construct method failed
 * due to lack of memory) attempt to send a void method return.
 */
static
void
jack_dbus_send_method_return(
    struct jack_dbus_method_call * call)
{
    if (call->reply)
    {
    retry_send:
        if (!dbus_connection_send (call->connection, call->reply, NULL))
        {
            jack_error ("Ran out of memory trying to queue method return");
        }

        dbus_connection_flush (call->connection);
        dbus_message_unref (call->reply);
        call->reply = NULL;
    }
    else
    {
        jack_error ("send_method_return() called with a NULL message,"
                    " trying to construct a void return...");

        if ((call->reply = dbus_message_new_method_return (call->message)))
        {
            goto retry_send;
        }
        else
        {
            jack_error ("Failed to construct method return!");
        }
    }
}

#define object_ptr ((struct jack_dbus_object_descriptor *)data)

/*
 * The D-Bus message handler for object path /org/jackaudio/Controller.
 */
DBusHandlerResult
jack_dbus_message_handler(
    DBusConnection *connection,
    DBusMessage *message,
    void *data)
{
    struct jack_dbus_method_call call;
    const char *interface_name;
    struct jack_dbus_interface_descriptor ** interface_ptr_ptr;

    /* Check if the message is a method call. If not, ignore it. */
    if (dbus_message_get_type (message) != DBUS_MESSAGE_TYPE_METHOD_CALL)
    {
        goto handled;
    }

    /* Get the invoked method's name and make sure it's non-NULL. */
    if (!(call.method_name = dbus_message_get_member (message)))
    {
        jack_error ("dbus_message_get_member() returned NULL");
        goto handled;
    }

    /* Initialize our data. */
    call.context = object_ptr->context;
    call.connection = connection;
    call.message = message;
    call.reply = NULL;

    /* Check if there's an interface specified for this method call. */
    interface_name = dbus_message_get_interface (message);
    if (interface_name != NULL)
    {
        /* Check if we can match the interface and method.
         * The inteface handler functions only return false if the
         * method name was unknown, otherwise they run the specified
         * method and return TRUE.
         */

        interface_ptr_ptr = object_ptr->interfaces;

        while (*interface_ptr_ptr != NULL)
        {
            if (strcmp(interface_name, (*interface_ptr_ptr)->name) == 0)
            {
                if (!(*interface_ptr_ptr)->handler(&call, (*interface_ptr_ptr)->methods))
                {
                    break;
                }

                goto send_return;
            }

            interface_ptr_ptr++;
        }
    }
    else
    {
        /* No interface was specified so we have to try them all. This is
         * dictated by the D-Bus specification which states that method calls
         * omitting the interface must never be rejected.
         */

        interface_ptr_ptr = object_ptr->interfaces;

        while (*interface_ptr_ptr != NULL)
        {
            if ((*interface_ptr_ptr)->handler(&call, (*interface_ptr_ptr)->methods))
            {
                goto send_return;
            }

            interface_ptr_ptr++;
        }
    }

    jack_dbus_error(
        &call,
        JACK_DBUS_ERROR_UNKNOWN_METHOD,
        "Method \"%s\" with signature \"%s\" on interface \"%s\" doesn't exist",
        call.method_name,
        dbus_message_get_signature(message),
        interface_name);

send_return:
    jack_dbus_send_method_return(&call);

handled:
    return DBUS_HANDLER_RESULT_HANDLED;
}

void
jack_dbus_message_handler_unregister(
    DBusConnection *connection,
    void *data)
{
    jack_info ("Message handler was unregistered");
}

#undef object_ptr

/*
 * Check if the supplied method name exists in org.jackaudio.JackConfigure,
 * if it does execute it and return TRUE. Otherwise return FALSE.
 */
bool
jack_dbus_run_method(
    struct jack_dbus_method_call *call,
    const struct jack_dbus_interface_method_descriptor * methods)
{
    const struct jack_dbus_interface_method_descriptor * method_ptr;

    method_ptr = methods;

    while (method_ptr->name != NULL)
    {
        if (strcmp(call->method_name, method_ptr->name) == 0)
        {
            method_ptr->handler(call);
            return TRUE;
        }

        method_ptr++;
    }

    return FALSE;
}

/*
 * Read arguments from a method call.
 * If the operation fails construct an error and return false,
 * otherwise return true.
 */
bool
jack_dbus_get_method_args(
    struct jack_dbus_method_call *call,
    int type,
    ...)
{
    va_list args;
    DBusError error;
    bool retval = true;

    va_start (args, type);
    dbus_error_init (&error);

    if (!dbus_message_get_args_valist (call->message, &error, type, args))
    {
        jack_dbus_error (call, JACK_DBUS_ERROR_INVALID_ARGS,
                         "Invalid arguments to method \"%s\"",
                         call->method_name);
        retval = false;
    }

    dbus_error_free (&error);
    va_end (args);

    return retval;
}

/*
 * Read a string and a variant argument from a method call.
 * If the operation fails construct an error and return false,
 * otherwise return true.
 */
bool
jack_dbus_get_method_args_string_and_variant(
    struct jack_dbus_method_call *call,
    const char **arg1,
    message_arg_t *arg2,
    int *type_ptr)
{
    DBusMessageIter iter, sub_iter;

    /* First we want a string... */
    if (dbus_message_iter_init (call->message, &iter)
        && dbus_message_iter_get_arg_type (&iter) == DBUS_TYPE_STRING)
    {
        dbus_message_iter_get_basic (&iter, arg1);
        dbus_message_iter_next (&iter);

        /* ...and then a variant. */
        if (dbus_message_iter_get_arg_type (&iter) == DBUS_TYPE_VARIANT)
        {
            dbus_message_iter_recurse (&iter, &sub_iter);
            dbus_message_iter_get_basic (&sub_iter, arg2);
            *type_ptr = dbus_message_iter_get_arg_type (&sub_iter);

            /* Got what we wanted. */
            return true;
        }
    }

    jack_dbus_error (call, JACK_DBUS_ERROR_INVALID_ARGS,
                     "Invalid arguments to method \"%s\"",
                     call->method_name);

    return false;
}

/*
 * Append a variant type to a D-Bus message.
 * Return false if something fails, true otherwise.
 */
bool
jack_dbus_message_append_variant(
    DBusMessageIter *iter,
    int type,
    const char *signature,
    message_arg_t *arg)
{
    DBusMessageIter sub_iter;

    /* Open a variant container. */
    if (!dbus_message_iter_open_container (iter, DBUS_TYPE_VARIANT, signature, &sub_iter))
    {
        goto fail;
    }

    /* Append the supplied value. */
    if (!dbus_message_iter_append_basic (&sub_iter, type, (const void *) arg))
    {
        dbus_message_iter_close_container (iter, &sub_iter);
        goto fail;
    }

    /* Close the container. */
    if (!dbus_message_iter_close_container (iter, &sub_iter))
    {
        goto fail;
    }

    return true;

fail:
    return false;
}

/*
 * Construct an empty method return message.
 *
 * The operation can only fail due to lack of memory, in which case
 * there's no sense in trying to construct an error return. Instead,
 * call->reply will be set to NULL and handled in send_method_return().
 */
void
jack_dbus_construct_method_return_empty(
    struct jack_dbus_method_call * call)
{
    call->reply = dbus_message_new_method_return (call->message);

    if (call->reply == NULL)
    {
        jack_error ("Ran out of memory trying to construct method return");
    }
}

/*
 * Construct a method return which holds a single argument or, if
 * the type parameter is DBUS_TYPE_INVALID, no arguments at all
 * (a void message).
 *
 * The operation can only fail due to lack of memory, in which case
 * there's no sense in trying to construct an error return. Instead,
 * call->reply will be set to NULL and handled in send_method_return().
 */
void
jack_dbus_construct_method_return_single(
    struct jack_dbus_method_call *call,
    int type,
    message_arg_t arg)
{
    DBusMessageIter iter;
    call->reply = dbus_message_new_method_return (call->message);

    if (call->reply == NULL)
    {
        goto fail_no_mem;
    }

    /* Void method return requested by caller. */
    if (type == DBUS_TYPE_INVALID)
    {
        return;
    }

    /* Prevent crash on NULL input string. */
    else if (type == DBUS_TYPE_STRING && arg.string == NULL)
    {
        arg.string = "";
    }

    dbus_message_iter_init_append (call->reply, &iter);

    if (!dbus_message_iter_append_basic (&iter, type, (const void *) &arg))
    {
        dbus_message_unref (call->reply);
        call->reply = NULL;
        goto fail_no_mem;
    }

    return;

fail_no_mem:
    jack_error ("Ran out of memory trying to construct method return");
}

/*
 * Construct a method return which holds an array of strings.
 *
 * The operation can only fail due to lack of memory, in which case
 * there's no sense in trying to construct an error return. Instead,
 * call->reply will be set to NULL and handled in send_method_return().
 */
void
jack_dbus_construct_method_return_array_of_strings(
    struct jack_dbus_method_call *call,
    unsigned int num_members,
    const char **array)
{
    DBusMessageIter iter, sub_iter;
    unsigned int i;

    call->reply = dbus_message_new_method_return (call->message);
    if (!call->reply)
    {
        goto fail;
    }

    dbus_message_iter_init_append (call->reply, &iter);

    if (!dbus_message_iter_open_container (&iter, DBUS_TYPE_ARRAY, "s", &sub_iter))
    {
        goto fail_unref;
    }

    for (i = 0; i < num_members; ++i)
    {
        if (!dbus_message_iter_append_basic (&sub_iter, DBUS_TYPE_STRING, (const void *) &array[i]))
        {
            dbus_message_iter_close_container (&iter, &sub_iter);
            goto fail_unref;
        }
    }

    if (!dbus_message_iter_close_container (&iter, &sub_iter))
    {
        goto fail_unref;
    }

    return;

fail_unref:
    dbus_message_unref (call->reply);
    call->reply = NULL;

fail:
    jack_error ("Ran out of memory trying to construct method return");
}

void 
jack_dbus_info_callback(const char *msg)
{
    time_t timestamp;
    char timestamp_str[26];

    time(&timestamp);
    ctime_r(&timestamp, timestamp_str);
    timestamp_str[24] = 0;

    fprintf(g_logfile, "%s: %s\n", timestamp_str, msg);
    fflush(g_logfile);
}

void 
jack_dbus_error_callback(const char *msg)
{
    time_t timestamp;
    char timestamp_str[26];

    time(&timestamp);
    ctime_r(&timestamp, timestamp_str);
    timestamp_str[24] = 0;

    fprintf(g_logfile, "%s: ERROR: %s\n", timestamp_str, msg);
    fflush(g_logfile);
}

int
paths_init()
{
    const char *home_dir;
    struct stat st;
    size_t home_dir_len;
    size_t jackdbus_dir_len;
    
    home_dir = getenv("HOME");
    if (home_dir == NULL)
    {
        fprintf(stderr, "Environment variable HOME not set\n");
        goto fail;
    }

    home_dir_len = strlen(home_dir);
    jackdbus_dir_len = strlen(JACKDBUS_DIR);

    g_jackdbus_dir = malloc(home_dir_len + jackdbus_dir_len + 1);
    if (g_jackdbus_dir == NULL)
    {
        fprintf(stderr, "Out of memory\n");
        goto fail;
    }

    memcpy(g_jackdbus_dir, home_dir, home_dir_len);
    memcpy(g_jackdbus_dir + home_dir_len, JACKDBUS_DIR, jackdbus_dir_len);
    g_jackdbus_dir_len = home_dir_len + jackdbus_dir_len;
    g_jackdbus_dir[g_jackdbus_dir_len] = 0;

    if (stat(g_jackdbus_dir, &st) != 0)
    {
        if (errno == ENOENT)
        {
            printf("Directory \"%s\" does not exist. Creating...\n", g_jackdbus_dir);
            if (mkdir(g_jackdbus_dir, 0777) != 0)
            {
                fprintf(stderr, "Failed to create \"%s\" directory: %d (%s)\n", g_jackdbus_dir, errno, strerror(errno));
                goto fail_free;
            }
        }
        else
        {
            fprintf(stderr, "Failed to stat \"%s\": %d (%s)\n", g_jackdbus_dir, errno, strerror(errno));
            goto fail_free;
        }
    }
    else
    {
        if (!S_ISDIR(st.st_mode))
        {
            fprintf(stderr, "\"%s\" exists but is not directory.\n", g_jackdbus_dir);
            goto fail_free;
        }
    }

    return TRUE;

fail_free:
    free(g_jackdbus_dir);

fail:
    return FALSE;
}

void
paths_uninit()
{
    free(g_jackdbus_dir);
}

int
log_init()
{
    char *log_filename;
    size_t log_len;

    log_len = strlen(JACKDBUS_LOG);

    log_filename = malloc(g_jackdbus_dir_len + log_len + 1);
    if (log_filename == NULL)
    {
        fprintf(stderr, "Out of memory\n");
        return FALSE;
    }

    memcpy(log_filename, g_jackdbus_dir, g_jackdbus_dir_len);
    memcpy(log_filename + g_jackdbus_dir_len, JACKDBUS_LOG, log_len);
    log_filename[g_jackdbus_dir_len + log_len] = 0;

    g_logfile = fopen(log_filename, "a");
    if (g_logfile == NULL)
    {
        fprintf(stderr, "Cannot open jackdbus log file \"%s\": %d (%s)\n", log_filename, errno, strerror(errno));
        free(log_filename);
        return FALSE;
    }

    free(log_filename);

    return TRUE;
}

void
log_uninit()
{
    fclose(g_logfile);
}

void
jack_dbus_error(
    void *dbus_call_context_ptr,
    const char *error_name,
    const char *format,
    ...)
{
    va_list ap;
    char buffer[300];

    va_start(ap, format);

    vsnprintf(buffer, sizeof(buffer), format, ap);

    jack_error_callback(buffer);
    if (dbus_call_context_ptr != NULL)
    {
        ((struct jack_dbus_method_call *)dbus_call_context_ptr)->reply = dbus_message_new_error(
            ((struct jack_dbus_method_call *)dbus_call_context_ptr)->message,
            error_name,
            buffer);
    }

    va_end(ap);
}

static void 
do_nothing_handler (int sig)
{
    /* this is used by the child (active) process, but it never
       gets called unless we are already shutting down after
       another signal.
    */
    char buf[64];
    snprintf (buf, sizeof(buf),
          "received signal %d during shutdown (ignored)\n", sig);
    write (1, buf, strlen (buf));
}

void
do_signal_magic()
{
    sigset_t signals;
    sigset_t allsignals;
    struct sigaction action;
    int i;

    /* ensure that we are in our own process group so that
       kill (SIG, -pgrp) does the right thing.
    */

    setsid();

    pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);

    /* what's this for?

       POSIX says that signals are delivered like this:

       * if a thread has blocked that signal, it is not
           a candidate to receive the signal.
           * of all threads not blocking the signal, pick
           one at random, and deliver the signal.

           this means that a simple-minded multi-threaded program can
           expect to get POSIX signals delivered randomly to any one
           of its threads,

       here, we block all signals that we think we might receive
       and want to catch. all "child" threads will inherit this
       setting. if we create a thread that calls sigwait() on the
       same set of signals, implicitly unblocking all those
       signals. any of those signals that are delivered to the
       process will be delivered to that thread, and that thread
       alone. this makes cleanup for a signal-driven exit much
       easier, since we know which thread is doing it and more
       importantly, we are free to call async-unsafe functions,
       because the code is executing in normal thread context
       after a return from sigwait().
    */

    sigemptyset(&signals);
    sigaddset(&signals, SIGHUP);
    sigaddset(&signals, SIGINT);
    sigaddset(&signals, SIGQUIT);
    sigaddset(&signals, SIGPIPE);
    sigaddset(&signals, SIGTERM);
    sigaddset(&signals, SIGUSR1);
    sigaddset(&signals, SIGUSR2);

    /* all child threads will inherit this mask unless they
     * explicitly reset it 
     */

    pthread_sigmask (SIG_BLOCK, &signals, 0);

    /* install a do-nothing handler because otherwise pthreads
       behaviour is undefined when we enter sigwait.
    */

    sigfillset (&allsignals);
    action.sa_handler = do_nothing_handler;
    action.sa_mask = allsignals;
    action.sa_flags = SA_RESTART|SA_RESETHAND;

    for (i = 1; i < NSIG; i++) {
        if (sigismember (&signals, i)) {
            sigaction (i, &action, 0);
        } 
    }
}

int
main (int argc, char **argv)
{
    DBusError error;
    int ret;
        void *controller_ptr;

    if (!jack_controller_settings_init())
    {
        ret = 1;
        goto fail;
    }

    if (argc != 2 || strcmp(argv[1], "auto") != 0)
    {
        ret = 0;
        fprintf(
            stderr,
            "jackdbus should be auto-executed by D-Bus message bus daemon.\n"
            "If you want to run it manually anyway, specify \"auto\" as only parameter\n");
        goto fail_uninit_xml;
    }

    if (!paths_init())
    {
        ret = 1;
        goto fail_uninit_xml;
    }

    if (!log_init())
    {
        ret = 1;
        goto fail_uninit_paths;
    }

#if !defined(DISABLE_SIGNAL_MAGIC)
    do_signal_magic();
#endif

    jack_set_error_function(jack_dbus_error_callback);
    jack_set_info_function(jack_dbus_info_callback);

    jack_info("------------------");
    jack_info("Controller activated. Version " VERSION);

    if (!dbus_threads_init_default())
    {
        jack_error("dbus_threads_init_default() failed");
        ret = 1;
        goto fail_uninit_log;
    }

    dbus_error_init (&error);
    g_connection = dbus_bus_get (DBUS_BUS_SESSION, &error);
    if (dbus_error_is_set (&error))
    {
        jack_error("Cannot connect to D-Bus session bus: %s", error.message);
        ret = 1;
        goto fail_uninit_log;
    }

    ret = dbus_bus_request_name(
                g_connection,
                "org.jackaudio.service",
                DBUS_NAME_FLAG_DO_NOT_QUEUE,
                &error);
    if (ret == -1)
    {
        jack_error("Cannot request service name: %s", error.message);
                dbus_error_free(&error);
        ret = 1;
        goto fail_unref_connection;
    }
    else if (ret == DBUS_REQUEST_NAME_REPLY_EXISTS)
    {
        jack_error("Requested D-Bus service name already exists");
        ret = 1;
        goto fail_unref_connection;
    }

    controller_ptr = jack_controller_create(g_connection);

    if (controller_ptr == NULL)
    {
        ret = 1;
        goto fail_unref_connection;
    }

    jack_info("Listening for D-Bus messages");

    g_exit_command = FALSE;
    while (!g_exit_command && dbus_connection_read_write_dispatch (g_connection, 200));

    jack_controller_destroy(controller_ptr);

    jack_info("Controller deactivated.");

    ret = 0;

fail_unref_connection:
    dbus_connection_unref(g_connection);

fail_uninit_log:
    log_uninit();

fail_uninit_paths:
    paths_uninit();

fail_uninit_xml:
    jack_controller_settings_uninit();

fail:
    return ret;
}