cmds/dumpstate/dumpstate.c

/*
 * Copyright (C) 2008 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 <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/capability.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <unistd.h>

#include <cutils/properties.h>

#include "private/android_filesystem_config.h"

#define LOG_TAG "dumpstate"
#include <cutils/log.h>

#include "dumpstate.h"

/* read before root is shed */
static char cmdline_buf[16384] = "(unknown)";
static const char *dump_traces_path = NULL;

static char screenshot_path[PATH_MAX] = "";

#define PSTORE_LAST_KMSG "/sys/fs/pstore/console-ramoops"

#define TOMBSTONE_DIR "/data/tombstones"
#define TOMBSTONE_FILE_PREFIX TOMBSTONE_DIR "/tombstone_"
/* Can accomodate a tombstone number up to 9999. */
#define TOMBSTONE_MAX_LEN (sizeof(TOMBSTONE_FILE_PREFIX) + 4)
#define NUM_TOMBSTONES  10

typedef struct {
  char name[TOMBSTONE_MAX_LEN];
  int fd;
} tombstone_data_t;

static tombstone_data_t tombstone_data[NUM_TOMBSTONES];

/* Get the fds of any tombstone that was modified in the last half an hour. */
static void get_tombstone_fds(tombstone_data_t data[NUM_TOMBSTONES]) {
    time_t thirty_minutes_ago = time(NULL) - 60*30;
    for (size_t i = 0; i < NUM_TOMBSTONES; i++) {
        snprintf(data[i].name, sizeof(data[i].name), "%s%02zu", TOMBSTONE_FILE_PREFIX, i);
        int fd = TEMP_FAILURE_RETRY(open(data[i].name,
                                         O_RDONLY | O_CLOEXEC | O_NOFOLLOW | O_NONBLOCK));
        struct stat st;
        if (fstat(fd, &st) == 0 && S_ISREG(st.st_mode) &&
                (time_t) st.st_mtime >= thirty_minutes_ago) {
            data[i].fd = fd;
        } else {
            close(fd);
            data[i].fd = -1;
        }
    }
}

static void dump_dev_files(const char *title, const char *driverpath, const char *filename)
{
    DIR *d;
    struct dirent *de;
    char path[PATH_MAX];

    d = opendir(driverpath);
    if (d == NULL) {
        return;
    }

    while ((de = readdir(d))) {
        if (de->d_type != DT_LNK) {
            continue;
        }
        snprintf(path, sizeof(path), "%s/%s/%s", driverpath, de->d_name, filename);
        dump_file(title, path);
    }

    closedir(d);
}

/* dumps the current system state to stdout */
static void dumpstate() {
    time_t now = time(NULL);
    char build[PROPERTY_VALUE_MAX], fingerprint[PROPERTY_VALUE_MAX];
    char radio[PROPERTY_VALUE_MAX], bootloader[PROPERTY_VALUE_MAX];
    char network[PROPERTY_VALUE_MAX], date[80];
    char build_type[PROPERTY_VALUE_MAX];

    property_get("ro.build.display.id", build, "(unknown)");
    property_get("ro.build.fingerprint", fingerprint, "(unknown)");
    property_get("ro.build.type", build_type, "(unknown)");
    property_get("ro.baseband", radio, "(unknown)");
    property_get("ro.bootloader", bootloader, "(unknown)");
    property_get("gsm.operator.alpha", network, "(unknown)");
    strftime(date, sizeof(date), "%Y-%m-%d %H:%M:%S", localtime(&now));

    printf("========================================================\n");
    printf("== dumpstate: %s\n", date);
    printf("========================================================\n");

    printf("\n");
    printf("Build: %s\n", build);
    printf("Build fingerprint: '%s'\n", fingerprint); /* format is important for other tools */
    printf("Bootloader: %s\n", bootloader);
    printf("Radio: %s\n", radio);
    printf("Network: %s\n", network);

    printf("Kernel: ");
    dump_file(NULL, "/proc/version");
    printf("Command line: %s\n", strtok(cmdline_buf, "\n"));
    printf("\n");

    dump_dev_files("TRUSTY VERSION", "/sys/bus/platform/drivers/trusty", "trusty_version");
    run_command("UPTIME", 10, "uptime", NULL);
    dump_file("MMC PERF", "/sys/block/mmcblk0/stat");
    dump_file("MEMORY INFO", "/proc/meminfo");
    run_command("CPU INFO", 10, "top", "-n", "1", "-d", "1", "-m", "30", "-t", NULL);
    run_command("PROCRANK", 20, "procrank", NULL);
    dump_file("VIRTUAL MEMORY STATS", "/proc/vmstat");
    dump_file("VMALLOC INFO", "/proc/vmallocinfo");
    dump_file("SLAB INFO", "/proc/slabinfo");
    dump_file("ZONEINFO", "/proc/zoneinfo");
    dump_file("PAGETYPEINFO", "/proc/pagetypeinfo");
    dump_file("BUDDYINFO", "/proc/buddyinfo");
    dump_file("FRAGMENTATION INFO", "/d/extfrag/unusable_index");

    dump_file("KERNEL WAKELOCKS", "/proc/wakelocks");
    dump_file("KERNEL WAKE SOURCES", "/d/wakeup_sources");
    dump_file("KERNEL CPUFREQ", "/sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state");
    dump_file("KERNEL SYNC", "/d/sync");
    dump_file("KERNEL BLUEDROID", "/d/bluedroid");

    run_command("PROCESSES", 10, "ps", "-P", NULL);
    run_command("PROCESSES AND THREADS", 10, "ps", "-t", "-p", "-P", NULL);
    run_command("PROCESSES (SELINUX LABELS)", 10, "ps", "-Z", NULL);
    run_command("LIBRANK", 10, "librank", NULL);

    do_dmesg();

    run_command("LIST OF OPEN FILES", 10, SU_PATH, "root", "lsof", NULL);
    for_each_pid(do_showmap, "SMAPS OF ALL PROCESSES");
    for_each_tid(show_wchan, "BLOCKED PROCESS WAIT-CHANNELS");

    if (screenshot_path[0]) {
        ALOGI("taking screenshot\n");
        run_command(NULL, 10, "/system/bin/screencap", "-p", screenshot_path, NULL);
        ALOGI("wrote screenshot: %s\n", screenshot_path);
    }

    // dump_file("EVENT LOG TAGS", "/etc/event-log-tags");
    run_command("SYSTEM LOG", 20, "logcat", "-v", "threadtime", "-d", "*:v", NULL);
    run_command("EVENT LOG", 20, "logcat", "-b", "events", "-v", "threadtime", "-d", "*:v", NULL);
    run_command("RADIO LOG", 20, "logcat", "-b", "radio", "-v", "threadtime", "-d", "*:v", NULL);

    /* show the traces we collected in main(), if that was done */
    if (dump_traces_path != NULL) {
        dump_file("VM TRACES JUST NOW", dump_traces_path);
    }

    /* only show ANR traces if they're less than 15 minutes old */
    struct stat st;
    char anr_traces_path[PATH_MAX];
    property_get("dalvik.vm.stack-trace-file", anr_traces_path, "");
    if (!anr_traces_path[0]) {
        printf("*** NO VM TRACES FILE DEFINED (dalvik.vm.stack-trace-file)\n\n");
    } else {
      int fd = TEMP_FAILURE_RETRY(open(anr_traces_path,
                                       O_RDONLY | O_CLOEXEC | O_NOFOLLOW | O_NONBLOCK));
      if (fd < 0) {
          printf("*** NO ANR VM TRACES FILE (%s): %s\n\n", anr_traces_path, strerror(errno));
      } else {
          dump_file_from_fd("VM TRACES AT LAST ANR", anr_traces_path, fd);
      }
    }

    /* slow traces for slow operations */
    if (anr_traces_path[0] != 0) {
        int tail = strlen(anr_traces_path)-1;
        while (tail > 0 && anr_traces_path[tail] != '/') {
            tail--;
        }
        int i = 0;
        while (1) {
            sprintf(anr_traces_path+tail+1, "slow%02d.txt", i);
            if (stat(anr_traces_path, &st)) {
                // No traces file at this index, done with the files.
                break;
            }
            dump_file("VM TRACES WHEN SLOW", anr_traces_path);
            i++;
        }
    }

    int dumped = 0;
    for (size_t i = 0; i < NUM_TOMBSTONES; i++) {
        if (tombstone_data[i].fd != -1) {
            dumped = 1;
            dump_file_from_fd("TOMBSTONE", tombstone_data[i].name, tombstone_data[i].fd);
            tombstone_data[i].fd = -1;
        }
    }
    if (!dumped) {
        printf("*** NO TOMBSTONES to dump in %s\n\n", TOMBSTONE_DIR);
    }

    dump_file("NETWORK DEV INFO", "/proc/net/dev");
    dump_file("QTAGUID NETWORK INTERFACES INFO", "/proc/net/xt_qtaguid/iface_stat_all");
    dump_file("QTAGUID NETWORK INTERFACES INFO (xt)", "/proc/net/xt_qtaguid/iface_stat_fmt");
    dump_file("QTAGUID CTRL INFO", "/proc/net/xt_qtaguid/ctrl");
    dump_file("QTAGUID STATS INFO", "/proc/net/xt_qtaguid/stats");

    if (!stat(PSTORE_LAST_KMSG, &st)) {
        /* Also TODO: Make console-ramoops CAP_SYSLOG protected. */
        dump_file("LAST KMSG", PSTORE_LAST_KMSG);
    } else {
        /* TODO: Make last_kmsg CAP_SYSLOG protected. b/5555691 */
        dump_file("LAST KMSG", "/proc/last_kmsg");
    }

    dump_file("LAST PANIC CONSOLE", "/data/dontpanic/apanic_console");
    dump_file("LAST PANIC THREADS", "/data/dontpanic/apanic_threads");

    /* kernels must set CONFIG_PSTORE_PMSG, slice up pstore with device tree */
    run_command("LAST LOGCAT", 10, "logcat", "-L", "-v", "threadtime",
                                             "-b", "all", "-d", "*:v", NULL);

    /* The following have a tendency to get wedged when wifi drivers/fw goes belly-up. */

    run_command("NETWORK INTERFACES", 10, "ip", "link", NULL);

    run_command("IPv4 ADDRESSES", 10, "ip", "-4", "addr", "show", NULL);
    run_command("IPv6 ADDRESSES", 10, "ip", "-6", "addr", "show", NULL);

    run_command("IP RULES", 10, "ip", "rule", "show", NULL);
    run_command("IP RULES v6", 10, "ip", "-6", "rule", "show", NULL);

    dump_route_tables();

    run_command("ARP CACHE", 10, "ip", "-4", "neigh", "show", NULL);
    run_command("IPv6 ND CACHE", 10, "ip", "-6", "neigh", "show", NULL);

    run_command("IPTABLES", 10, SU_PATH, "root", "iptables", "-L", "-nvx", NULL);
    run_command("IP6TABLES", 10, SU_PATH, "root", "ip6tables", "-L", "-nvx", NULL);
    run_command("IPTABLE NAT", 10, SU_PATH, "root", "iptables", "-t", "nat", "-L", "-nvx", NULL);
    /* no ip6 nat */
    run_command("IPTABLE RAW", 10, SU_PATH, "root", "iptables", "-t", "raw", "-L", "-nvx", NULL);
    run_command("IP6TABLE RAW", 10, SU_PATH, "root", "ip6tables", "-t", "raw", "-L", "-nvx", NULL);

    run_command("WIFI NETWORKS", 20,
            SU_PATH, "root", "wpa_cli", "IFNAME=wlan0", "list_networks", NULL);

#ifdef FWDUMP_bcmdhd
    run_command("DUMP WIFI INTERNAL COUNTERS", 20,
            SU_PATH, "root", "wlutil", "counters", NULL);
#endif
    dump_file("INTERRUPTS (1)", "/proc/interrupts");

    property_get("dhcp.wlan0.gateway", network, "");
    if (network[0])
        run_command("PING GATEWAY", 10, "ping", "-c", "3", "-i", ".5", network, NULL);
    property_get("dhcp.wlan0.dns1", network, "");
    if (network[0])
        run_command("PING DNS1", 10, "ping", "-c", "3", "-i", ".5", network, NULL);
    property_get("dhcp.wlan0.dns2", network, "");
    if (network[0])
        run_command("PING DNS2", 10, "ping", "-c", "3", "-i", ".5", network, NULL);
#ifdef FWDUMP_bcmdhd
    run_command("DUMP WIFI STATUS", 20,
            SU_PATH, "root", "dhdutil", "-i", "wlan0", "dump", NULL);
    run_command("DUMP WIFI INTERNAL COUNTERS", 20,
            SU_PATH, "root", "wlutil", "counters", NULL);
#endif
    dump_file("INTERRUPTS (2)", "/proc/interrupts");

    print_properties();

    run_command("VOLD DUMP", 10, "vdc", "dump", NULL);
    run_command("SECURE CONTAINERS", 10, "vdc", "asec", "list", NULL);

    run_command("FILESYSTEMS & FREE SPACE", 10, "df", NULL);

    run_command("LAST RADIO LOG", 10, "parse_radio_log", "/proc/last_radio_log", NULL);

    printf("------ BACKLIGHTS ------\n");
    printf("LCD brightness=");
    dump_file(NULL, "/sys/class/leds/lcd-backlight/brightness");
    printf("Button brightness=");
    dump_file(NULL, "/sys/class/leds/button-backlight/brightness");
    printf("Keyboard brightness=");
    dump_file(NULL, "/sys/class/leds/keyboard-backlight/brightness");
    printf("ALS mode=");
    dump_file(NULL, "/sys/class/leds/lcd-backlight/als");
    printf("LCD driver registers:\n");
    dump_file(NULL, "/sys/class/leds/lcd-backlight/registers");
    printf("\n");

    /* Binder state is expensive to look at as it uses a lot of memory. */
    dump_file("BINDER FAILED TRANSACTION LOG", "/sys/kernel/debug/binder/failed_transaction_log");
    dump_file("BINDER TRANSACTION LOG", "/sys/kernel/debug/binder/transaction_log");
    dump_file("BINDER TRANSACTIONS", "/sys/kernel/debug/binder/transactions");
    dump_file("BINDER STATS", "/sys/kernel/debug/binder/stats");
    dump_file("BINDER STATE", "/sys/kernel/debug/binder/state");

    printf("========================================================\n");
    printf("== Board\n");
    printf("========================================================\n");

    dumpstate_board();
    printf("\n");

    /* Migrate the ril_dumpstate to a dumpstate_board()? */
    char ril_dumpstate_timeout[PROPERTY_VALUE_MAX] = {0};
    property_get("ril.dumpstate.timeout", ril_dumpstate_timeout, "30");
    if (strnlen(ril_dumpstate_timeout, PROPERTY_VALUE_MAX - 1) > 0) {
        if (0 == strncmp(build_type, "user", PROPERTY_VALUE_MAX - 1)) {
            // su does not exist on user builds, so try running without it.
            // This way any implementations of vril-dump that do not require
            // root can run on user builds.
            run_command("DUMP VENDOR RIL LOGS", atoi(ril_dumpstate_timeout),
                    "vril-dump", NULL);
        } else {
            run_command("DUMP VENDOR RIL LOGS", atoi(ril_dumpstate_timeout),
                    SU_PATH, "root", "vril-dump", NULL);
        }
    }

    printf("========================================================\n");
    printf("== Android Framework Services\n");
    printf("========================================================\n");

    /* the full dumpsys is starting to take a long time, so we need
       to increase its timeout.  we really need to do the timeouts in
       dumpsys itself... */
    run_command("DUMPSYS", 60, "dumpsys", NULL);

    printf("========================================================\n");
    printf("== Checkins\n");
    printf("========================================================\n");

    run_command("CHECKIN BATTERYSTATS", 30, "dumpsys", "batterystats", "-c", NULL);
    run_command("CHECKIN MEMINFO", 30, "dumpsys", "meminfo", "--checkin", NULL);
    run_command("CHECKIN NETSTATS", 30, "dumpsys", "netstats", "--checkin", NULL);
    run_command("CHECKIN PROCSTATS", 30, "dumpsys", "procstats", "-c", NULL);
    run_command("CHECKIN USAGESTATS", 30, "dumpsys", "usagestats", "-c", NULL);

    printf("========================================================\n");
    printf("== Running Application Activities\n");
    printf("========================================================\n");

    run_command("APP ACTIVITIES", 30, "dumpsys", "activity", "all", NULL);

    printf("========================================================\n");
    printf("== Running Application Services\n");
    printf("========================================================\n");

    run_command("APP SERVICES", 30, "dumpsys", "activity", "service", "all", NULL);

    printf("========================================================\n");
    printf("== Running Application Providers\n");
    printf("========================================================\n");

    run_command("APP SERVICES", 30, "dumpsys", "activity", "provider", "all", NULL);


    printf("========================================================\n");
    printf("== dumpstate: done\n");
    printf("========================================================\n");
}

static void usage() {
    fprintf(stderr, "usage: dumpstate [-b soundfile] [-e soundfile] [-o file [-d] [-p] [-z]] [-s] [-q]\n"
            "  -o: write to file (instead of stdout)\n"
            "  -d: append date to filename (requires -o)\n"
            "  -p: capture screenshot to filename.png (requires -o)\n"
            "  -s: write output to control socket (for init)\n"
            "  -b: play sound file instead of vibrate, at beginning of job\n"
            "  -e: play sound file instead of vibrate, at end of job\n"
            "  -q: disable vibrate\n"
            "  -B: send broadcast when finished (requires -o and -p)\n"
                );
}

static void sigpipe_handler(int n) {
    // don't complain to stderr or stdout
    _exit(EXIT_FAILURE);
}

static void vibrate(FILE* vibrator, int ms) {
    fprintf(vibrator, "%d\n", ms);
    fflush(vibrator);
}

int main(int argc, char *argv[]) {
    struct sigaction sigact;
    int do_add_date = 0;
    int do_vibrate = 1;
    char* use_outfile = 0;
    int use_socket = 0;
    int do_fb = 0;
    int do_broadcast = 0;

    if (getuid() != 0) {
        // Old versions of the adb client would call the
        // dumpstate command directly. Newer clients
        // call /system/bin/bugreport instead. If we detect
        // we're being called incorrectly, then exec the
        // correct program.
        return execl("/system/bin/bugreport", "/system/bin/bugreport", NULL);
    }

    ALOGI("begin\n");

    /* clear SIGPIPE handler */
    memset(&sigact, 0, sizeof(sigact));
    sigact.sa_handler = sigpipe_handler;
    sigaction(SIGPIPE, &sigact, NULL);

    /* set as high priority, and protect from OOM killer */
    setpriority(PRIO_PROCESS, 0, -20);
    FILE *oom_adj = fopen("/proc/self/oom_adj", "we");
    if (oom_adj) {
        fputs("-17", oom_adj);
        fclose(oom_adj);
    }

    /* parse arguments */
    int c;
    while ((c = getopt(argc, argv, "dho:svqzpB")) != -1) {
        switch (c) {
            case 'd': do_add_date = 1;       break;
            case 'o': use_outfile = optarg;  break;
            case 's': use_socket = 1;        break;
            case 'v': break;  // compatibility no-op
            case 'q': do_vibrate = 0;        break;
            case 'p': do_fb = 1;             break;
            case 'B': do_broadcast = 1;      break;
            case '?': printf("\n");
            case 'h':
                usage();
                exit(1);
        }
    }

    // If we are going to use a socket, do it as early as possible
    // to avoid timeouts from bugreport.
    if (use_socket) {
        redirect_to_socket(stdout, "dumpstate");
    }

    /* open the vibrator before dropping root */
    FILE *vibrator = 0;
    if (do_vibrate) {
        vibrator = fopen("/sys/class/timed_output/vibrator/enable", "we");
        if (vibrator) {
            vibrate(vibrator, 150);
        }
    }

    /* read /proc/cmdline before dropping root */
    FILE *cmdline = fopen("/proc/cmdline", "re");
    if (cmdline != NULL) {
        fgets(cmdline_buf, sizeof(cmdline_buf), cmdline);
        fclose(cmdline);
    }

    /* collect stack traces from Dalvik and native processes (needs root) */
    dump_traces_path = dump_traces();

    /* Get the tombstone fds here while we are running as root. */
    get_tombstone_fds(tombstone_data);

    /* ensure we will keep capabilities when we drop root */
    if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
        ALOGE("prctl(PR_SET_KEEPCAPS) failed: %s\n", strerror(errno));
        return -1;
    }

    /* switch to non-root user and group */
    gid_t groups[] = { AID_LOG, AID_SDCARD_R, AID_SDCARD_RW,
            AID_MOUNT, AID_INET, AID_NET_BW_STATS };
    if (setgroups(sizeof(groups)/sizeof(groups[0]), groups) != 0) {
        ALOGE("Unable to setgroups, aborting: %s\n", strerror(errno));
        return -1;
    }
    if (setgid(AID_SHELL) != 0) {
        ALOGE("Unable to setgid, aborting: %s\n", strerror(errno));
        return -1;
    }
    if (setuid(AID_SHELL) != 0) {
        ALOGE("Unable to setuid, aborting: %s\n", strerror(errno));
        return -1;
    }

    struct __user_cap_header_struct capheader;
    struct __user_cap_data_struct capdata[2];
    memset(&capheader, 0, sizeof(capheader));
    memset(&capdata, 0, sizeof(capdata));
    capheader.version = _LINUX_CAPABILITY_VERSION_3;
    capheader.pid = 0;

    capdata[CAP_TO_INDEX(CAP_SYSLOG)].permitted = CAP_TO_MASK(CAP_SYSLOG);
    capdata[CAP_TO_INDEX(CAP_SYSLOG)].effective = CAP_TO_MASK(CAP_SYSLOG);
    capdata[0].inheritable = 0;
    capdata[1].inheritable = 0;

    if (capset(&capheader, &capdata[0]) < 0) {
        ALOGE("capset failed: %s\n", strerror(errno));
        return -1;
    }

    /* redirect output if needed */
    char path[PATH_MAX], tmp_path[PATH_MAX];
    pid_t gzip_pid = -1;

    if (!use_socket && use_outfile) {
        strlcpy(path, use_outfile, sizeof(path));
        if (do_add_date) {
            char date[80];
            time_t now = time(NULL);
            strftime(date, sizeof(date), "-%Y-%m-%d-%H-%M-%S", localtime(&now));
            strlcat(path, date, sizeof(path));
        }
        if (do_fb) {
            strlcpy(screenshot_path, path, sizeof(screenshot_path));
            strlcat(screenshot_path, ".png", sizeof(screenshot_path));
        }
        strlcat(path, ".txt", sizeof(path));
        strlcpy(tmp_path, path, sizeof(tmp_path));
        strlcat(tmp_path, ".tmp", sizeof(tmp_path));
        redirect_to_file(stdout, tmp_path);
    }

    dumpstate();

    /* done */
    if (vibrator) {
        for (int i = 0; i < 3; i++) {
            vibrate(vibrator, 75);
            usleep((75 + 50) * 1000);
        }
        fclose(vibrator);
    }

    /* wait for gzip to finish, otherwise it might get killed when we exit */
    if (gzip_pid > 0) {
        fclose(stdout);
        waitpid(gzip_pid, NULL, 0);
    }

    /* rename the (now complete) .tmp file to its final location */
    if (use_outfile && rename(tmp_path, path)) {
        fprintf(stderr, "rename(%s, %s): %s\n", tmp_path, path, strerror(errno));
    }

    /* tell activity manager we're done */
    if (do_broadcast && use_outfile && do_fb) {
        run_command(NULL, 5, "/system/bin/am", "broadcast", "--user", "0",
                "-a", "android.intent.action.BUGREPORT_FINISHED",
                "--es", "android.intent.extra.BUGREPORT", path,
                "--es", "android.intent.extra.SCREENSHOT", screenshot_path,
                "--receiver-permission", "android.permission.DUMP", NULL);
    }

    ALOGI("done\n");

    return 0;
}