init/keychords.cpp

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <linux/keychord.h>
#include <unistd.h>

#include "init.h"
#include "log.h"
#include "property_service.h"
#include "service.h"

static struct input_keychord *keychords = 0;
static int keychords_count = 0;
static int keychords_length = 0;
static int keychord_fd = -1;

void add_service_keycodes(Service* svc)
{
    struct input_keychord *keychord;
    size_t i, size;

    if (!svc->keycodes().empty()) {
        /* add a new keychord to the list */
        size = sizeof(*keychord) + svc->keycodes().size() * sizeof(keychord->keycodes[0]);
        keychords = (input_keychord*) realloc(keychords, keychords_length + size);
        if (!keychords) {
            ERROR("could not allocate keychords\n");
            keychords_length = 0;
            keychords_count = 0;
            return;
        }

        keychord = (struct input_keychord *)((char *)keychords + keychords_length);
        keychord->version = KEYCHORD_VERSION;
        keychord->id = keychords_count + 1;
        keychord->count = svc->keycodes().size();
        svc->set_keychord_id(keychord->id);

        for (i = 0; i < svc->keycodes().size(); i++) {
            keychord->keycodes[i] = svc->keycodes()[i];
        }
        keychords_count++;
        keychords_length += size;
    }
}

static void handle_keychord() {
    int ret;
    __u16 id;

    ret = read(keychord_fd, &id, sizeof(id));
    if (ret != sizeof(id)) {
        ERROR("could not read keychord id\n");
        return;
    }

    // Only handle keychords if adb is enabled.
    std::string adb_enabled = property_get("init.svc.adbd");
    if (adb_enabled == "running") {
        Service* svc = ServiceManager::GetInstance().FindServiceByKeychord(id);
        if (svc) {
            NOTICE("Starting service '%s' from keychord %d\n", svc->name().c_str(), id);
            svc->Start();
        } else {
            ERROR("Service for keychord %d not found\n", id);
        }
    } else {
        WARNING("Not starting service for keychord %d because ADB is disabled\n", id);
    }
}

void keychord_init() {
    ServiceManager::GetInstance().ForEachService(add_service_keycodes);

    // Nothing to do if no services require keychords.
    if (!keychords) {
        return;
    }

    keychord_fd = TEMP_FAILURE_RETRY(open("/dev/keychord", O_RDWR | O_CLOEXEC));
    if (keychord_fd == -1) {
        ERROR("could not open /dev/keychord: %s\n", strerror(errno));
        return;
    }

    int ret = write(keychord_fd, keychords, keychords_length);
    if (ret != keychords_length) {
        ERROR("could not configure /dev/keychord %d: %s\n", ret, strerror(errno));
        close(keychord_fd);
    }

    free(keychords);
    keychords = nullptr;

    register_epoll_handler(keychord_fd, handle_keychord);
}