path: root/src/udev/udev-builtin-input_id.c

/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * expose input properties via udev
 *
 * Portions Copyright © 2004 David Zeuthen, <david@fubar.dk>
 * Copyright © 2014 Carlos Garnacho <carlosg@gnome.org>
 */

#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <linux/limits.h>
#include <linux/input.h>

#include "device-util.h"
#include "fd-util.h"
#include "missing.h"
#include "stdio-util.h"
#include "string-util.h"
#include "udev-builtin.h"
#include "util.h"

/* we must use this kernel-compatible implementation */
#define BITS_PER_LONG (sizeof(unsigned long) * 8)
#define NBITS(x) ((((x)-1)/BITS_PER_LONG)+1)
#define OFF(x)  ((x)%BITS_PER_LONG)
#define BIT(x)  (1UL<<OFF(x))
#define LONG(x) ((x)/BITS_PER_LONG)
#define test_bit(bit, array)    ((array[LONG(bit)] >> OFF(bit)) & 1)

struct range {
        unsigned start;
        unsigned end;
};

/* key code ranges above BTN_MISC (start is inclusive, stop is exclusive)*/
static const struct range high_key_blocks[] = {
        { KEY_OK, BTN_DPAD_UP },
        { KEY_ALS_TOGGLE, BTN_TRIGGER_HAPPY }
};

static int abs_size_mm(const struct input_absinfo *absinfo) {
        /* Resolution is defined to be in units/mm for ABS_X/Y */
        return (absinfo->maximum - absinfo->minimum) / absinfo->resolution;
}

static void extract_info(sd_device *dev, const char *devpath, bool test) {
        char width[DECIMAL_STR_MAX(int)], height[DECIMAL_STR_MAX(int)];
        struct input_absinfo xabsinfo = {}, yabsinfo = {};
        _cleanup_close_ int fd = -1;

        fd = open(devpath, O_RDONLY|O_CLOEXEC);
        if (fd < 0)
                return;

        if (ioctl(fd, EVIOCGABS(ABS_X), &xabsinfo) < 0 ||
            ioctl(fd, EVIOCGABS(ABS_Y), &yabsinfo) < 0)
                return;

        if (xabsinfo.resolution <= 0 || yabsinfo.resolution <= 0)
                return;

        xsprintf(width, "%d", abs_size_mm(&xabsinfo));
        xsprintf(height, "%d", abs_size_mm(&yabsinfo));

        udev_builtin_add_property(dev, test, "ID_INPUT_WIDTH_MM", width);
        udev_builtin_add_property(dev, test, "ID_INPUT_HEIGHT_MM", height);
}

/*
 * Read a capability attribute and return bitmask.
 * @param dev sd_device
 * @param attr sysfs attribute name (e. g. "capabilities/key")
 * @param bitmask: Output array which has a sizeof of bitmask_size
 */
static void get_cap_mask(sd_device *pdev, const char* attr,
                         unsigned long *bitmask, size_t bitmask_size,
                         bool test) {
        const char *v;
        char text[4096];
        unsigned i;
        char* word;
        unsigned long val;

        if (sd_device_get_sysattr_value(pdev, attr, &v) < 0)
                v = "";

        xsprintf(text, "%s", v);
        log_device_debug(pdev, "%s raw kernel attribute: %s", attr, text);

        memzero(bitmask, bitmask_size);
        i = 0;
        while ((word = strrchr(text, ' ')) != NULL) {
                val = strtoul(word+1, NULL, 16);
                if (i < bitmask_size / sizeof(unsigned long))
                        bitmask[i] = val;
                else
                        log_device_debug(pdev, "Ignoring %s block %lX which is larger than maximum size", attr, val);
                *word = '\0';
                ++i;
        }
        val = strtoul (text, NULL, 16);
        if (i < bitmask_size / sizeof(unsigned long))
                bitmask[i] = val;
        else
                log_device_debug(pdev, "Ignoring %s block %lX which is larger than maximum size", attr, val);

        if (test) {
                /* printf pattern with the right unsigned long number of hex chars */
                xsprintf(text, "  bit %%4u: %%0%zulX\n",
                         2 * sizeof(unsigned long));
                log_device_debug(pdev, "%s decoded bit map:", attr);
                val = bitmask_size / sizeof (unsigned long);
                /* skip over leading zeros */
                while (bitmask[val-1] == 0 && val > 0)
                        --val;
                for (i = 0; i < val; ++i) {
                        DISABLE_WARNING_FORMAT_NONLITERAL;
                        log_device_debug(pdev, text, i * BITS_PER_LONG, bitmask[i]);
                        REENABLE_WARNING;
                }
        }
}

/* pointer devices */
static bool test_pointers(sd_device *dev,
                          const unsigned long* bitmask_ev,
                          const unsigned long* bitmask_abs,
                          const unsigned long* bitmask_key,
                          const unsigned long* bitmask_rel,
                          const unsigned long* bitmask_props,
                          bool test) {
        int button, axis;
        bool has_abs_coordinates = false;
        bool has_rel_coordinates = false;
        bool has_mt_coordinates = false;
        bool has_joystick_axes_or_buttons = false;
        bool is_direct = false;
        bool has_touch = false;
        bool has_3d_coordinates = false;
        bool has_keys = false;
        bool stylus_or_pen = false;
        bool finger_but_no_pen = false;
        bool has_mouse_button = false;
        bool is_mouse = false;
        bool is_touchpad = false;
        bool is_touchscreen = false;
        bool is_tablet = false;
        bool is_joystick = false;
        bool is_accelerometer = false;
        bool is_pointing_stick= false;

        has_keys = test_bit(EV_KEY, bitmask_ev);
        has_abs_coordinates = test_bit(ABS_X, bitmask_abs) && test_bit(ABS_Y, bitmask_abs);
        has_3d_coordinates = has_abs_coordinates && test_bit(ABS_Z, bitmask_abs);
        is_accelerometer = test_bit(INPUT_PROP_ACCELEROMETER, bitmask_props);

        if (!has_keys && has_3d_coordinates)
                is_accelerometer = true;

        if (is_accelerometer) {
                udev_builtin_add_property(dev, test, "ID_INPUT_ACCELEROMETER", "1");
                return true;
        }

        is_pointing_stick = test_bit(INPUT_PROP_POINTING_STICK, bitmask_props);
        stylus_or_pen = test_bit(BTN_STYLUS, bitmask_key) || test_bit(BTN_TOOL_PEN, bitmask_key);
        finger_but_no_pen = test_bit(BTN_TOOL_FINGER, bitmask_key) && !test_bit(BTN_TOOL_PEN, bitmask_key);
        for (button = BTN_MOUSE; button < BTN_JOYSTICK && !has_mouse_button; button++)
                has_mouse_button = test_bit(button, bitmask_key);
        has_rel_coordinates = test_bit(EV_REL, bitmask_ev) && test_bit(REL_X, bitmask_rel) && test_bit(REL_Y, bitmask_rel);
        has_mt_coordinates = test_bit(ABS_MT_POSITION_X, bitmask_abs) && test_bit(ABS_MT_POSITION_Y, bitmask_abs);

        /* unset has_mt_coordinates if devices claims to have all abs axis */
        if (has_mt_coordinates && test_bit(ABS_MT_SLOT, bitmask_abs) && test_bit(ABS_MT_SLOT - 1, bitmask_abs))
                has_mt_coordinates = false;
        is_direct = test_bit(INPUT_PROP_DIRECT, bitmask_props);
        has_touch = test_bit(BTN_TOUCH, bitmask_key);

        /* joysticks don't necessarily have buttons; e. g.
         * rudders/pedals are joystick-like, but buttonless; they have
         * other fancy axes. Others have buttons only but no axes.
         *
         * The BTN_JOYSTICK range starts after the mouse range, so a mouse
         * with more than 16 buttons runs into the joystick range (e.g. Mad
         * Catz Mad Catz M.M.O.TE). Skip those.
         */
        if (!test_bit(BTN_JOYSTICK - 1, bitmask_key)) {
                for (button = BTN_JOYSTICK; button < BTN_DIGI && !has_joystick_axes_or_buttons; button++)
                        has_joystick_axes_or_buttons = test_bit(button, bitmask_key);
                for (button = BTN_TRIGGER_HAPPY1; button <= BTN_TRIGGER_HAPPY40 && !has_joystick_axes_or_buttons; button++)
                        has_joystick_axes_or_buttons = test_bit(button, bitmask_key);
                for (button = BTN_DPAD_UP; button <= BTN_DPAD_RIGHT && !has_joystick_axes_or_buttons; button++)
                        has_joystick_axes_or_buttons = test_bit(button, bitmask_key);
        }
        for (axis = ABS_RX; axis < ABS_PRESSURE && !has_joystick_axes_or_buttons; axis++)
                has_joystick_axes_or_buttons = test_bit(axis, bitmask_abs);

        if (has_abs_coordinates) {
                if (stylus_or_pen)
                        is_tablet = true;
                else if (finger_but_no_pen && !is_direct)
                        is_touchpad = true;
                else if (has_mouse_button)
                        /* This path is taken by VMware's USB mouse, which has
                         * absolute axes, but no touch/pressure button. */
                        is_mouse = true;
                else if (has_touch || is_direct)
                        is_touchscreen = true;
                else if (has_joystick_axes_or_buttons)
                        is_joystick = true;
        } else if (has_joystick_axes_or_buttons) {
                is_joystick = true;
        }

        if (has_mt_coordinates) {
                if (stylus_or_pen)
                        is_tablet = true;
                else if (finger_but_no_pen && !is_direct)
                        is_touchpad = true;
                else if (has_touch || is_direct)
                        is_touchscreen = true;
        }

        if (!is_tablet && !is_touchpad && !is_joystick &&
            has_mouse_button &&
            (has_rel_coordinates ||
            !has_abs_coordinates)) /* mouse buttons and no axis */
                is_mouse = true;

        if (is_pointing_stick)
                udev_builtin_add_property(dev, test, "ID_INPUT_POINTINGSTICK", "1");
        if (is_mouse)
                udev_builtin_add_property(dev, test, "ID_INPUT_MOUSE", "1");
        if (is_touchpad)
                udev_builtin_add_property(dev, test, "ID_INPUT_TOUCHPAD", "1");
        if (is_touchscreen)
                udev_builtin_add_property(dev, test, "ID_INPUT_TOUCHSCREEN", "1");
        if (is_joystick)
                udev_builtin_add_property(dev, test, "ID_INPUT_JOYSTICK", "1");
        if (is_tablet)
                udev_builtin_add_property(dev, test, "ID_INPUT_TABLET", "1");

        return is_tablet || is_mouse || is_touchpad || is_touchscreen || is_joystick || is_pointing_stick;
}

/* key like devices */
static bool test_key(sd_device *dev,
                     const unsigned long* bitmask_ev,
                     const unsigned long* bitmask_key,
                     bool test) {
        unsigned i;
        unsigned long found;
        unsigned long mask;
        bool ret = false;

        /* do we have any KEY_* capability? */
        if (!test_bit(EV_KEY, bitmask_ev)) {
                log_device_debug(dev, "test_key: no EV_KEY capability");
                return false;
        }

        /* only consider KEY_* here, not BTN_* */
        found = 0;
        for (i = 0; i < BTN_MISC/BITS_PER_LONG; ++i) {
                found |= bitmask_key[i];
                log_device_debug(dev, "test_key: checking bit block %lu for any keys; found=%i", (unsigned long)i*BITS_PER_LONG, found > 0);
        }
        /* If there are no keys in the lower block, check the higher blocks */
        if (!found) {
                unsigned block;
                for (block = 0; block < (sizeof(high_key_blocks) / sizeof(struct range)); ++block) {
                        for (i = high_key_blocks[block].start; i < high_key_blocks[block].end; ++i) {
                                if (test_bit(i, bitmask_key)) {
                                        log_device_debug(dev, "test_key: Found key %x in high block", i);
                                        found = 1;
                                        break;
                                }
                        }
                }
        }

        if (found > 0) {
                udev_builtin_add_property(dev, test, "ID_INPUT_KEY", "1");
                ret = true;
        }

        /* the first 32 bits are ESC, numbers, and Q to D; if we have all of
         * those, consider it a full keyboard; do not test KEY_RESERVED, though */
        mask = 0xFFFFFFFE;
        if (FLAGS_SET(bitmask_key[0], mask)) {
                udev_builtin_add_property(dev, test, "ID_INPUT_KEYBOARD", "1");
                ret = true;
        }

        return ret;
}

static int builtin_input_id(sd_device *dev, int argc, char *argv[], bool test) {
        sd_device *pdev;
        unsigned long bitmask_ev[NBITS(EV_MAX)];
        unsigned long bitmask_abs[NBITS(ABS_MAX)];
        unsigned long bitmask_key[NBITS(KEY_MAX)];
        unsigned long bitmask_rel[NBITS(REL_MAX)];
        unsigned long bitmask_props[NBITS(INPUT_PROP_MAX)];
        const char *sysname, *devnode;
        bool is_pointer;
        bool is_key;

        assert(dev);

        /* walk up the parental chain until we find the real input device; the
         * argument is very likely a subdevice of this, like eventN */
        for (pdev = dev; pdev; ) {
                const char *s;

                if (sd_device_get_sysattr_value(pdev, "capabilities/ev", &s) >= 0)
                        break;

                if (sd_device_get_parent_with_subsystem_devtype(pdev, "input", NULL, &pdev) >= 0)
                        continue;

                pdev = NULL;
                break;
        }

        if (pdev) {
                /* Use this as a flag that input devices were detected, so that this
                 * program doesn't need to be called more than once per device */
                udev_builtin_add_property(dev, test, "ID_INPUT", "1");
                get_cap_mask(pdev, "capabilities/ev", bitmask_ev, sizeof(bitmask_ev), test);
                get_cap_mask(pdev, "capabilities/abs", bitmask_abs, sizeof(bitmask_abs), test);
                get_cap_mask(pdev, "capabilities/rel", bitmask_rel, sizeof(bitmask_rel), test);
                get_cap_mask(pdev, "capabilities/key", bitmask_key, sizeof(bitmask_key), test);
                get_cap_mask(pdev, "properties", bitmask_props, sizeof(bitmask_props), test);
                is_pointer = test_pointers(dev, bitmask_ev, bitmask_abs,
                                           bitmask_key, bitmask_rel,
                                           bitmask_props, test);
                is_key = test_key(dev, bitmask_ev, bitmask_key, test);
                /* Some evdev nodes have only a scrollwheel */
                if (!is_pointer && !is_key && test_bit(EV_REL, bitmask_ev) &&
                    (test_bit(REL_WHEEL, bitmask_rel) || test_bit(REL_HWHEEL, bitmask_rel)))
                        udev_builtin_add_property(dev, test, "ID_INPUT_KEY", "1");
                if (test_bit(EV_SW, bitmask_ev))
                        udev_builtin_add_property(dev, test, "ID_INPUT_SWITCH", "1");

        }

        if (sd_device_get_devname(dev, &devnode) >= 0 &&
            sd_device_get_sysname(dev, &sysname) >= 0 &&
            startswith(sysname, "event"))
                extract_info(dev, devnode, test);

        return 0;
}

const struct udev_builtin udev_builtin_input_id = {
        .name = "input_id",
        .cmd = builtin_input_id,
        .help = "Input device properties",
};