/**
* mds — A micro-display server
* Copyright © 2014, 2015, 2016 Mattias Andrée (maandree@member.fsf.org)
*
* 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 3 of the License, or
* (at your option) any later version.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include "mds-libinput.h"
#include <libmdsserver/macros.h>
#include <libmdsserver/util.h>
#include <libmdsserver/mds-message.h>
#include <linux/input.h>
#include <sys/select.h>
#include <inttypes.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#define reconnect_to_display() -1
#define MDS_LIBINPUT_VARS_VERSION 0
/**
* This variable should declared by the actual server implementation.
* It must be configured before `main` is invoked.
*
* This tells the server-base how to behave
*/
server_characteristics_t server_characteristics =
{
.require_privileges = 1,
.require_display = 1,
.require_respawn_info = 0,
.sanity_check_argc = 1,
.fork_for_safety = 0,
.danger_is_deadly = 0
};
/**
* Value of the ‘Message ID’ header for the next message
*/
static uint32_t message_id = 1;
/**
* Buffer for received messages
*/
static mds_message_t received;
/**
* Whether the server is connected to the display
*/
static int connected = 1;
/**
* The seat for libinput
*/
static const char* seat = "seat0";
/**
* libinput context
*/
static struct libinput* li = NULL;
/**
* udev context
*/
static struct udev* udev = NULL;
/**
* List of all opened devices
*/
static struct libinput_device **devices = NULL;
/**
* The number of element slots allocated for `devices`
*/
static size_t devices_size = 0;
/**
* The last element slot used in `devices`
*/
static size_t devices_used = 0;
/**
* The index of the first free slot in `devices`
*/
static size_t devices_ptr = 0;
/**
* The input event listener thread
*/
static pthread_t ev_thread;
/**
* Whether `ev_thread` has started
*/
static volatile sig_atomic_t ev_thread_started = 0;
/**
* Message buffer for the main thread
*/
static char* resp_send_buffer = NULL;
/**
* The size of `resp_send_buffer`
*/
static size_t resp_send_buffer_size = 0;
/**
* Message buffer for the event thread
*/
static char* anno_send_buffer = NULL;
/**
* The size of `anno_send_buffer`
*/
static size_t anno_send_buffer_size = 0;
/**
* File descriptor for the libinput events
*/
static int event_fd = -1;
/**
* File descriptor set for select(3):ing
* the libinput events
*/
static fd_set event_fd_set;
/**
* Whether the server has been signaled to
* free unneeded memory
*
* For event thread
*/
static volatile sig_atomic_t ev_danger = 0;
/**
* Whether the server has been signaled to
* output runtime information
*
* For event thread
*/
static volatile sig_atomic_t info = 0;
/**
* Mutex that should be used when accessing
* the device list
*/
static pthread_mutex_t dev_mutex;
/**
* Send a full message even if interrupted
*
* @param message:const char* The message to send
* @param length:size_t The length of the message
* @return :int Zero on success, -1 on error
*/
#define full_send(message, length) \
((full_send)(socket_fd, message, length))
/**
* Parse command line arguments
*
* @return Non-zero on error
*/
int parse_cmdline(void)
{
int i;
/* Parse command line arguments. */
for (i = 1; i < argc; i++)
{
char* arg = argv[i];
int v;
if ((v = strequals(arg, "--initial-spawn")) || /* Initial spawn? */
strequals(arg, "--respawn")) /* Respawning after crash? */
{
exit_if (is_respawn == v,
eprintf("conflicting arguments %s and %s cannot be combined.",
"--initial-spawn", "--respawn"););
is_respawn = !v;
}
else if (strequals(arg, "--re-exec")) /* Re-exec state-marshal. */
is_reexec = 1;
else if (startswith(arg, "--alarm=")) /* Schedule an alarm signal for forced abort. */
alarm(min(atou(arg + strlen("--alarm=")), 60)); /* At most 1 minute. */
else if (strequals(arg, "--on-init-fork")) /* Fork process when initialised. */
on_init_fork = 1;
else if (startswith(arg, "--on-init-sh=")) /* Run a command when initialised. */
on_init_sh = arg + strlen("--on-init-sh=");
else if (strequals(arg, "--immortal")) /* I return to serve. */
is_immortal = 1;
else if (startswith(arg, "--seat=")) /* Seat to pass to libinput. */
seat = arg + strlen("--seat=");
}
if (is_reexec)
{
is_respawn = 1;
eprint("re-exec performed.");
}
/* Check that mandatory arguments have been specified. */
if (server_characteristics.require_respawn_info)
exit_if (is_respawn < 0,
eprintf("missing state argument, require either %s or %s.",
"--initial-spawn", "--respawn"););
return 0;
}
/**
* This function will be invoked before `initialise_server` (if not re-exec:ing)
* or before `unmarshal_server` (if re-exec:ing)
*
* @return Non-zero on error
*/
int __attribute__((const)) preinitialise_server(void)
{
return 0;
}
/**
* This function should initialise the server,
* and it not invoked after a re-exec.
*
* @return Non-zero on error
*/
int initialise_server(void)
{
int stage = 0;
fail_if (server_initialised());
fail_if (mds_message_initialise(&received)); stage++;
return 0;
fail:
xperror(*argv);
if (stage >= 1) mds_message_destroy(&received);
return 1;
}
/**
* This function will be invoked after `initialise_server` (if not re-exec:ing)
* or after `unmarshal_server` (if re-exec:ing)
*
* @return Non-zero on error
*/
int postinitialise_server(void)
{
int stage = 0;
fail_if (initialise_libinput());
fail_if (pthread_mutex_init(&dev_mutex, NULL)); stage++;
if (connected)
return 0;
fail_if (reconnect_to_display());
connected = 1;
return 0;
fail:
terminate_libinput();
mds_message_destroy(&received);
if (stage >= 1) pthread_mutex_destroy(&dev_mutex);
return 1;
}
/**
* Calculate the number of bytes that will be stored by `marshal_server`
*
* On failure the program should `abort()` or exit by other means.
* However it should not be possible for this function to fail.
*
* @return The number of bytes that will be stored by `marshal_server`
*/
size_t marshal_server_size(void)
{
size_t rc = 2 * sizeof(int) + sizeof(uint32_t);
rc += mds_message_marshal_size(&received);
return rc;
}
/**
* Marshal server implementation specific data into a buffer
*
* @param state_buf The buffer for the marshalled data
* @return Non-zero on error
*/
int marshal_server(char* state_buf)
{
buf_set_next(state_buf, int, MDS_LIBINPUT_VARS_VERSION);
buf_set_next(state_buf, int, connected);
buf_set_next(state_buf, uint32_t, message_id);
mds_message_marshal(&received, state_buf);
mds_message_destroy(&received);
return 0;
}
/**
* Unmarshal server implementation specific data and update the servers state accordingly
*
* On critical failure the program should `abort()` or exit by other means.
* That is, do not let `reexec_failure_recover` run successfully, if it unrecoverable
* error has occurred or one severe enough that it is better to simply respawn.
*
* @param state_buf The marshalled data that as not been read already
* @return Non-zero on error
*/
int unmarshal_server(char* state_buf)
{
/* buf_get_next(state_buf, int, MDS_LIBINPUT_VARS_VERSION); */
buf_next(state_buf, int, 1);
buf_get_next(state_buf, int, connected);
buf_get_next(state_buf, uint32_t, message_id);
fail_if (mds_message_unmarshal(&received, state_buf));
return 0;
fail:
xperror(*argv);
mds_message_destroy(&received);
return -1;
}
/**
* Attempt to recover from a re-exec failure that has been
* detected after the server successfully updated it execution image
*
* @return Non-zero on error
*/
int __attribute__((const)) reexec_failure_recover(void)
{
return -1;
}
/**
* Send a singal to all threads except the current thread
*
* @param signo The signal
*/
void signal_all(int signo)
{
pthread_t current_thread = pthread_self();
if (pthread_equal(current_thread, master_thread) == 0)
pthread_kill(master_thread, signo);
if (ev_thread_started)
if (pthread_equal(current_thread, ev_thread) == 0)
pthread_kill(ev_thread, signo);
}
/**
* This function is called when a signal that
* signals that the system is running out of memory
* has been received
*
* @param signo The signal that has been received
*/
void received_danger(int signo)
{
SIGHANDLER_START;
(void) signo;
if ((danger == 0) || (ev_danger == 0))
{
danger = 1;
ev_danger = 1;
eprint("danger signal received.");
}
SIGHANDLER_END;
}
/**
* Perform the server's mission
*
* @return Non-zero on error
*/
int master_loop(void)
{
int rc = 1, joined = 0, r;
void* ev_ret;
/* Start thread that reads input events. */
fail_if ((errno = pthread_create(&ev_thread, NULL, event_loop, NULL)));
/* Listen for messages. */
while (!reexecing && !terminating)
{
if (info)
dump_info();
if (danger)
{
danger = 0;
free(resp_send_buffer), resp_send_buffer = NULL;
resp_send_buffer_size = 0;
pack_devices();
}
if (r = mds_message_read(&received, socket_fd), r == 0)
if (r = handle_message(), r == 0)
continue;
if (r == -2)
{
eprint("corrupt message received, aborting.");
goto done;
}
else if (errno == EINTR)
continue;
else
fail_if (errno != ECONNRESET);
eprint("lost connection to server.");
mds_message_destroy(&received);
mds_message_initialise(&received);
connected = 0;
fail_if (reconnect_to_display());
connected = 1;
}
joined = 1;
fail_if ((errno = pthread_join(ev_thread, &ev_ret)));
rc = ev_ret == NULL ? 0 : 1;
goto done;
fail:
xperror(*argv);
done:
free(resp_send_buffer);
if (!joined && (errno = pthread_join(ev_thread, NULL)))
xperror(*argv);
if (!rc && reexecing)
return 0;
mds_message_destroy(&received);
terminate_libinput();
return rc;
}
/**
* The event listener thread's main function
*
* @param data Input data
* @return Output data
*/
void* event_loop(void* data)
{
(void) data;
ev_thread_started = 1;
if (handle_event() < 0)
fail_if (errno != EINTR);
while (!reexecing && !terminating)
{
if (ev_danger)
{
ev_danger = 0;
free(anno_send_buffer), anno_send_buffer = NULL;
anno_send_buffer_size = 0;
}
FD_SET(event_fd, &event_fd_set);
if (select(event_fd + 1, &event_fd_set, NULL, NULL, NULL) < 0)
{
fail_if (errno != EINTR);
continue;
}
if (handle_event() < 0)
fail_if (errno != EINTR);
}
return NULL;
fail:
xperror(*argv);
raise(SIGTERM);
return (void*)1024;
}
/**
* Handle an event from libinput
*
* @return Zero on success, -1 on error
*/
int handle_event(void)
{
struct libinput_event *ev;
if ((errno = -libinput_dispatch(li)))
return -1;
while ((ev = libinput_get_event(li))) {
switch (libinput_event_get_type(ev)) {
/* TODO */
default:
break;
}
libinput_event_destroy(ev);
if ((errno = -libinput_dispatch(li)))
return -1;
}
return 0;
}
/**
* Handle the received message
*
* @return Zero on success, -1 on error
*/
int handle_message(void)
{
/* TODO */
return 0;
}
/**
* Used by libinput to open a device
*
* @param path The filename of the device
* @param flags The flags to open(3)
* @param userdata Not used
* @return The file descriptor, or `-errno` on error
*/
int open_restricted(const char *path, int flags, void *userdata)
{
int fd = open(path, flags);
if (fd < 0)
return perror(*argv), -errno;
return fd;
(void) userdata;
}
/**
* Used by libinput to close device
*
* @param fd The file descriptor of the device
* @param userdata Not used
*/
void close_restricted(int fd, void *userdata)
{
close(fd);
(void) userdata;
}
/**
* Acquire access of input devices
*
* @return Zero on success, -1 on error
*/
int initialise_libinput(void)
{
const struct libinput_interface interface = {
.open_restricted = open_restricted,
.close_restricted = close_restricted
};
if (!(udev = udev_new()))
return eprint("failed to initialize udev."), errno = 0, -1;
if (!(li = libinput_udev_create_context(&interface, NULL, udev)))
return eprint("failed to initialize context from udev."), errno = 0, -1;
if (libinput_udev_assign_seat(li, seat))
return eprintf("failed to set seat: %s", seat), errno = 0, -1;
event_fd = libinput_get_fd(li);
FD_ZERO(&event_fd_set);
return 0;
}
/**
* Release access of input devices
*/
void terminate_libinput(void)
{
while (devices_used--)
if (devices[devices_used])
libinput_device_unref(devices[devices_used]);
if (li) libinput_unref(li);
if (udev) udev_unref(udev);
}
/**
* Add a device to the device list
*
* @param dev The device
* @return Zero on success, -1 on error
*/
int add_device(struct libinput_device* dev)
{
if (devices_ptr == devices_size)
{
struct libinput_device** tmp;
if (yrealloc(tmp, devices, devices_size + 10, struct libinput_device*))
return -1;
devices_size += 10;
}
devices[devices_ptr++] = libinput_device_ref(dev);
while ((devices_ptr < devices_used) && devices[devices_ptr])
devices_ptr++;
return 0;
}
/**
* Remove a device from the device list
*
* @param dev The device
*/
void remove_device(struct libinput_device* dev)
{
size_t i;
for (i = 0; i < devices_used; i++)
if (devices[i] == dev)
{
libinput_device_unref(dev);
devices[i] = NULL;
if (i < devices_ptr)
devices_ptr = i;
if (i + 1 == devices_used)
devices_used -= 1;
break;
}
}
/**
* Pack the device list
*/
void pack_devices(void)
{
size_t i;
for (i = devices_ptr = 0; i < devices_used; i++)
if (devices[i])
devices[devices_ptr++] = devices[i];
devices_used = devices_ptr;
if (devices_used)
{
struct libinput_device** tmp;
if (yrealloc(tmp, devices, devices_used, struct libinput_device*))
return;
devices_size = devices_used;
}
else
{
free(devices), devices = NULL;
devices_size = 0;
}
}
/**
* This function is called when a signal that
* signals that the system to dump state information
* and statistics has been received
*
* @param signo The signal that has been received
*/
void received_info(int signo)
{
SIGHANDLER_START;
(void) signo;
info = 1;
SIGHANDLER_END;
}
/**
* The the state of the server
*/
void dump_info(void)
{
info = 1;
iprintf("next message ID: %" PRIu32, message_id);
iprintf("connected: %s", connected ? "yes" : "no");
iprintf("libinput seat: %s", seat);
iprintf("sigdanger pending (main): %s", danger ? "yes" : "no");
iprintf("sigdanger pending (event): %s", ev_danger ? "yes" : "no");
iprintf("response send buffer size: %zu bytes", resp_send_buffer_size);
iprintf("announce send buffer size: %zu bytes", anno_send_buffer_size);
iprintf("event file descriptor: %i", event_fd);
iprintf("event thread started: %s", ev_thread_started ? "yes" : "no");
/* TODO list devices -- with_mutex(dev_mutex, ); */
}
