path: root/src/input.c

/**
 * @file
 * @section AUTHORS
 *
 *  Authors:
 *       Eamon Walsh <ewalsh@tycho.nsa.gov>
 *
 * @section LICENSE
 *
 * This file is in the public domain.
 *
 * @section DESCRIPTION
 *
 * Two things here:
 * 1. Udev code to detect new input devices and start monitoring them.
 * 2. Handling of raw incoming input events from Linux.  The code to detect
 * secure key combinations that will be handled by the server (such as the
 * switch-between-guests key) is done here, in key_event().
 */

#include <sys/types.h>
#include <sys/select.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>

#include <libudev.h>
#include <linux/input.h>

#include "sys-queue.h"
#include "client.h"
#include "display.h"
#include "input.h"
#include "fd.h"

#define MAX_DEVICES 16
#define DEVICE_PATH_LEN 32
#define DEVICE_NAME_LEN 64
#define DEVICE_LEN (DEVICE_PATH_LEN + DEVICE_NAME_LEN)
#define DEVICE_STEM "/dev/input/event"
#define ABSOLUTE_INITIAL -5000

struct device {
    int fd;
    int x, y;
    char *path;
    char *name;
    TAILQ_ENTRY(device) next;
};

TAILQ_HEAD(device_list, device);

static struct device_list devices = TAILQ_HEAD_INITIALIZER(devices);
static struct udev_monitor *udev_monitor;

/* Key tracker */
/* XXX combine this with the set in dclient.c */
static fd_set keys_down;
static int nkeys;

/* Absolute mouse coordinates */
static int absx;
static int absy;

static int
is_sak_press(struct input_event *e)
{
    return (e->code == LINPICK_SWITCH_SAK || e->code == LINPICK_LABEL_SAK) &&
	e->value;
}

static void
key_event(struct input_event *e)
{
    static int secure;
    static int ctrl_down, alt_down;

    /* General state tracking goes here */
    if (e->value && !FD_ISSET(e->code, &keys_down)) {
	FD_SET(e->code, &keys_down);
	nkeys++;
    }
    if (!e->value && FD_ISSET(e->code, &keys_down)) {
	FD_CLR(e->code, &keys_down);
	nkeys--;
    }

    /* Specific keys we track for convenience */
    if (e->code == KEY_LEFTCTRL)
	ctrl_down = e->value;
    else if (e->code == KEY_LEFTALT)
	alt_down = e->value;

    /* Check if SAK combination has been entered */
    if (!secure && is_sak_press(e) && ctrl_down && alt_down) {
	/* SAK entered */
	active_display->send_key(active_display, 0, KEY_LEFTCTRL, absx, absy);
	active_display->send_key(active_display, 0, KEY_LEFTALT, absx, absy);
	display_secure_enter(e->code);
	secure = 1;
    }

    /* Check if keys have been released, causing return to guest */
    else if (secure && nkeys == 0) {
	secure = 0;
	display_secure_leave();
    }

    /* Send event to server in secure mode */
    else if (secure)
	display_key_event(e);

    /* Otherwise, send event to the active display */
    else
	active_display->send_key(active_display, e->value, e->code, absx, absy);
}

static void
motion_event(struct input_event *e)
{
    struct mouse_event m = { absx, absy, 0, 0, 0 };

    switch(e->code) {
    case REL_X:
	m.x = absx = clamp_value(absx + e->value, display_get_width());
	m.dx = e->value;
	break;
    case REL_Y:
	m.y = absy = clamp_value(absy + e->value, display_get_height());
	m.dy = e->value;
	break;
    case REL_WHEEL:
	m.dz = -e->value;
	break;
    default:
	printf("Unhandled relative axis %d\n", e->code);
    }

    display_position_event(absx, absy);
    active_display->send_mouse(active_display, &m);
}

static void
absolute_event(struct device *d, struct input_event *e)
{
    struct mouse_event m = { absx, absy, 0, 0, 0 };

    switch(e->code) {
    case ABS_X:
	m.dx = e->value - absx;
	m.x = absx = e->value;
	break;
    case ABS_Y:
	m.dy = e->value - absy;
	m.y = absy = e->value;
	break;
    default:
	break;
    }

    display_position_event(absx, absy);
    active_display->send_mouse(active_display, &m);
}

static void
input_event(void *closure)
{
    struct device *d = closure;
    struct input_event levt[64];
    int i, readlen;

    readlen = read(d->fd, levt, sizeof(levt));
    if (readlen <= 0)
	return;

    for (i =0; i < readlen / sizeof(*levt); i++) {
	switch (levt[i].type) {
	case EV_SYN:
	    switch(levt[i].code) {
	    case SYN_REPORT:
		break;
	    default:
		printf("SYN: %d\n", levt[i].code);
	    }
	    break;
	case EV_KEY:
	    key_event(levt + i);
	    break;
	case EV_REL:
	    motion_event(levt + i);
	    break;
	case EV_ABS:
	    absolute_event(d, levt + i);
	    break;
	case EV_MSC:
	    break;
	default:
	    printf("%d\n", levt[i].type);
	}
    }
}

static int
configure_absolute_device(int fd)
{
    struct input_absinfo ai;

    if (ioctl(fd, EVIOCGABS(ABS_X), &ai) < 0)
	return -1;

    ai.minimum = 0;
    ai.maximum = display_get_width() - 1;

    if (ioctl(fd, EVIOCSABS(ABS_X), &ai) < 0) {
	FD_LOG(0, "ioctl EVIOCSABS failed: %m\n");
	return -1;
    }

    if (ioctl(fd, EVIOCGABS(ABS_Y), &ai) < 0)
	return -1;

    ai.minimum = 0;
    ai.maximum = display_get_height() - 1;

    if (ioctl(fd, EVIOCSABS(ABS_Y), &ai) < 0) {
	FD_LOG(0, "ioctl EVIOCSABS failed: %m\n");
	return -1;
    }

    return 0;
}

static int
open_device(const char *path)
{
    struct device *d;
    int fd = -1;
    char *name = "(unknown)";
    unsigned int bits;

    d = calloc(DEVICE_LEN + sizeof(struct device), 1);
    if (!d)
	goto err;

    fd = open(path, O_RDWR);
    if (fd < 0)
	goto err;

    d->fd = fd;
    d->x = d->y = ABSOLUTE_INITIAL;
    d->path = (char *)(d + 1);
    d->name = (char *)(d + 1) + DEVICE_PATH_LEN;
    strncpy(d->path, path, DEVICE_PATH_LEN - 1);

    if (ioctl(fd, EVIOCGRAB, 1) < 0)
	goto err;

    if (ioctl(fd, EVIOCGNAME(DEVICE_NAME_LEN - 1), d->name) < 0)
	goto err;
    name = d->name;

    if (ioctl(fd, EVIOCGBIT(0, 4), &bits) < 0)
	goto err;
    if ((bits & (1 << EV_ABS)) && configure_absolute_device(fd) < 0)
	goto err;

    if (fd_set_handler(fd, input_event, d) < 0)
	goto err;

    TAILQ_INSERT_TAIL(&devices, d, next);
    return 0;
err:
    FD_LOG(1, "Warning: failed to open device '%s' on %s\n", name, path);
    free(d);
    if (fd >= 0) {
	ioctl(fd, EVIOCGRAB, 0);
	close(fd);
    }
    return -1;
}

/* -------------------------------------------------------------------- */

static void
close_device(struct device *d)
{
    ioctl(d->fd, EVIOCGRAB, 0);
    fd_set_handler(d->fd, NULL, NULL);
    close(d->fd);
    TAILQ_REMOVE(&devices, d, next);
    free(d);
}

static void
device_added(struct udev_device *udev_device)
{
    const char *path, *key, *value, *class;
    struct udev_list_entry *set, *entry;

    path = udev_device_get_devnode(udev_device);
    if (!path)
        return;

    if (strncmp(path, DEVICE_STEM, strlen(DEVICE_STEM)))
	return;

    class = udev_device_get_property_value(udev_device, "ID_CLASS");
    if (class && (!strcmp(class, "kbd") || !strcmp(class, "mouse"))) {
	open_device(path);
	return;
    }

    set = udev_device_get_properties_list_entry(udev_device);
    udev_list_entry_foreach(entry, set) {
        key = udev_list_entry_get_name(entry);
        if (!key)
            continue;
        value = udev_list_entry_get_value(entry);
        if (!strcmp(key, "ID_INPUT_KEY")) {
	    open_device(path);
        } else if (!strcmp(key, "ID_INPUT_MOUSE")) {
	    open_device(path);
        } else if (!strcmp(key, "ID_INPUT_JOYSTICK")) {
	    ;
        } else if (!strcmp(key, "ID_INPUT_TABLET")) {
	    ;
        } else if (!strcmp(key, "ID_INPUT_TOUCHPAD")) {
	    open_device(path);
        } else if (!strcmp(key, "ID_INPUT_TOUCHSCREEN")) {
	    ;
        }
    }
}

static void
device_removed(struct udev_device *udev_device)
{
    const char *path;
    struct device *d;

    path = udev_device_get_devnode(udev_device);
    if (!path)
        return;

    if (strncmp(path, DEVICE_STEM, strlen(DEVICE_STEM)))
	return;

    TAILQ_FOREACH(d, &devices, next)
	if (!strcmp(d->path, path)) {
	    close_device(d);
	    return;
	}

    FD_LOG(2, "Warning: failed to close device %s\n", path);
}

static void
udev_event(void *closure)
{
    struct udev_device *udev_device;
    const char *action;

    udev_device = udev_monitor_receive_device(udev_monitor);
    if (udev_device) {
	action = udev_device_get_action(udev_device);
	if (action) {
	    if (!strcmp(action, "add"))
		device_added(udev_device);
	    else if (!strcmp(action, "remove"))
		device_removed(udev_device);
	}
	udev_device_unref(udev_device);
    }
}

int
input_initialize(int argc, char *argv[])
{
    struct udev *udev;
    struct udev_enumerate *enumerate;
    struct udev_list_entry *devices, *device;
    int fd;

    if (!(udev = udev_new()))
	goto err;
    if (!(udev_monitor = udev_monitor_new_from_netlink(udev, "udev")))
	goto err;
    if (udev_monitor_enable_receiving(udev_monitor))
	goto err;

    if (!(enumerate = udev_enumerate_new(udev)))
	goto err;
    udev_enumerate_scan_devices(enumerate);
    devices = udev_enumerate_get_list_entry(enumerate);
    udev_list_entry_foreach(device, devices) {
        const char *syspath = udev_list_entry_get_name(device);
        struct udev_device *udev_device = udev_device_new_from_syspath(udev, syspath);
        device_added(udev_device);
        udev_device_unref(udev_device);
    }
    udev_enumerate_unref(enumerate);

    fd = udev_monitor_get_fd(udev_monitor);
    if (fd_set_handler(fd, udev_event, NULL) < 0)
	goto err;

    absx = display_get_width() / 2;
    absy = display_get_height() / 2;

    return 0;
err:
    FD_LOG(0, "Failed to set up udev.\n");
    return -1;
}

void
input_shutdown(void)
{
    struct udev *udev;
    int fd;

    udev = udev_monitor_get_udev(udev_monitor);
    fd = udev_monitor_get_fd(udev_monitor);
    fd_set_handler(fd, NULL, NULL);
    udev_monitor_unref(udev_monitor);
    udev_unref(udev);

    while (!TAILQ_EMPTY(&devices))
	close_device(TAILQ_FIRST(&devices));
}