cmds/dumpstate/utils.cpp

/*
 * 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.
 */

#define LOG_TAG "dumpstate"

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <poll.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/capability.h>
#include <sys/inotify.h>
#include <sys/klog.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#include <string>
#include <vector>

#include <android-base/file.h>
#include <cutils/properties.h>
#include <cutils/sockets.h>
#include <debuggerd/client.h>
#include <log/log.h>
#include <private/android_filesystem_config.h>

#include <selinux/android.h>

#include "dumpstate.h"

static const int64_t NANOS_PER_SEC = 1000000000;

/* list of native processes to include in the native dumps */
// This matches the /proc/pid/exe link instead of /proc/pid/cmdline.
static const char* native_processes_to_dump[] = {
        "/system/bin/audioserver",
        "/system/bin/cameraserver",
        "/system/bin/drmserver",
        "/system/bin/mediacodec",     // media.codec
        "/system/bin/mediadrmserver",
        "/system/bin/mediaextractor", // media.extractor
        "/system/bin/mediaserver",
        "/system/bin/sdcard",
        "/system/bin/surfaceflinger",
        "/system/bin/vehicle_network_service",
        NULL,
};

DurationReporter::DurationReporter(const char *title) : DurationReporter(title, stdout) {}

DurationReporter::DurationReporter(const char *title, FILE *out) {
    title_ = title;
    if (title) {
        started_ = DurationReporter::nanotime();
    }
    out_ = out;
}

DurationReporter::~DurationReporter() {
    if (title_) {
        uint64_t elapsed = DurationReporter::nanotime() - started_;
        // Use "Yoda grammar" to make it easier to grep|sort sections.
        if (out_) {
            fprintf(out_, "------ %.3fs was the duration of '%s' ------\n",
                   (float) elapsed / NANOS_PER_SEC, title_);
        } else {
            MYLOGD("Duration of '%s': %.3fs\n", title_, (float) elapsed / NANOS_PER_SEC);
        }
    }
}

uint64_t DurationReporter::DurationReporter::nanotime() {
    struct timespec ts;
    clock_gettime(CLOCK_MONOTONIC, &ts);
    return (uint64_t) ts.tv_sec * NANOS_PER_SEC + ts.tv_nsec;
}

void for_each_userid(void (*func)(int), const char *header) {
    ON_DRY_RUN_RETURN();
    DIR *d;
    struct dirent *de;

    if (header) printf("\n------ %s ------\n", header);
    func(0);

    if (!(d = opendir("/data/system/users"))) {
        printf("Failed to open /data/system/users (%s)\n", strerror(errno));
        return;
    }

    while ((de = readdir(d))) {
        int userid;
        if (de->d_type != DT_DIR || !(userid = atoi(de->d_name))) {
            continue;
        }
        func(userid);
    }

    closedir(d);
}

static void __for_each_pid(void (*helper)(int, const char *, void *), const char *header, void *arg) {
    DIR *d;
    struct dirent *de;

    if (!(d = opendir("/proc"))) {
        printf("Failed to open /proc (%s)\n", strerror(errno));
        return;
    }

    if (header) printf("\n------ %s ------\n", header);
    while ((de = readdir(d))) {
        int pid;
        int fd;
        char cmdpath[255];
        char cmdline[255];

        if (!(pid = atoi(de->d_name))) {
            continue;
        }

        memset(cmdline, 0, sizeof(cmdline));

        snprintf(cmdpath, sizeof(cmdpath), "/proc/%d/cmdline", pid);
        if ((fd = TEMP_FAILURE_RETRY(open(cmdpath, O_RDONLY | O_CLOEXEC))) >= 0) {
            TEMP_FAILURE_RETRY(read(fd, cmdline, sizeof(cmdline) - 2));
            close(fd);
            if (cmdline[0]) {
                helper(pid, cmdline, arg);
                continue;
            }
        }

        // if no cmdline, a kernel thread has comm
        snprintf(cmdpath, sizeof(cmdpath), "/proc/%d/comm", pid);
        if ((fd = TEMP_FAILURE_RETRY(open(cmdpath, O_RDONLY | O_CLOEXEC))) >= 0) {
            TEMP_FAILURE_RETRY(read(fd, cmdline + 1, sizeof(cmdline) - 4));
            close(fd);
            if (cmdline[1]) {
                cmdline[0] = '[';
                size_t len = strcspn(cmdline, "\f\b\r\n");
                cmdline[len] = ']';
                cmdline[len+1] = '\0';
            }
        }
        if (!cmdline[0]) {
            strcpy(cmdline, "N/A");
        }
        helper(pid, cmdline, arg);
    }

    closedir(d);
}

static void for_each_pid_helper(int pid, const char *cmdline, void *arg) {
    for_each_pid_func *func = (for_each_pid_func*) arg;
    func(pid, cmdline);
}

void for_each_pid(for_each_pid_func func, const char *header) {
    ON_DRY_RUN_RETURN();
    __for_each_pid(for_each_pid_helper, header, (void *) func);
}

static void for_each_tid_helper(int pid, const char *cmdline, void *arg) {
    DIR *d;
    struct dirent *de;
    char taskpath[255];
    for_each_tid_func *func = (for_each_tid_func *) arg;

    snprintf(taskpath, sizeof(taskpath), "/proc/%d/task", pid);

    if (!(d = opendir(taskpath))) {
        printf("Failed to open %s (%s)\n", taskpath, strerror(errno));
        return;
    }

    func(pid, pid, cmdline);

    while ((de = readdir(d))) {
        int tid;
        int fd;
        char commpath[255];
        char comm[255];

        if (!(tid = atoi(de->d_name))) {
            continue;
        }

        if (tid == pid)
            continue;

        snprintf(commpath, sizeof(commpath), "/proc/%d/comm", tid);
        memset(comm, 0, sizeof(comm));
        if ((fd = TEMP_FAILURE_RETRY(open(commpath, O_RDONLY | O_CLOEXEC))) < 0) {
            strcpy(comm, "N/A");
        } else {
            char *c;
            TEMP_FAILURE_RETRY(read(fd, comm, sizeof(comm) - 2));
            close(fd);

            c = strrchr(comm, '\n');
            if (c) {
                *c = '\0';
            }
        }
        func(pid, tid, comm);
    }

    closedir(d);
}

void for_each_tid(for_each_tid_func func, const char *header) {
    ON_DRY_RUN_RETURN();
    __for_each_pid(for_each_tid_helper, header, (void *) func);
}

void show_wchan(int pid, int tid, const char *name) {
    ON_DRY_RUN_RETURN();
    char path[255];
    char buffer[255];
    int fd, ret, save_errno;
    char name_buffer[255];

    memset(buffer, 0, sizeof(buffer));

    snprintf(path, sizeof(path), "/proc/%d/wchan", tid);
    if ((fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY | O_CLOEXEC))) < 0) {
        printf("Failed to open '%s' (%s)\n", path, strerror(errno));
        return;
    }

    ret = TEMP_FAILURE_RETRY(read(fd, buffer, sizeof(buffer)));
    save_errno = errno;
    close(fd);

    if (ret < 0) {
        printf("Failed to read '%s' (%s)\n", path, strerror(save_errno));
        return;
    }

    snprintf(name_buffer, sizeof(name_buffer), "%*s%s",
             pid == tid ? 0 : 3, "", name);

    printf("%-7d %-32s %s\n", tid, name_buffer, buffer);

    return;
}

// print time in centiseconds
static void snprcent(char *buffer, size_t len, size_t spc,
                     unsigned long long time) {
    static long hz; // cache discovered hz

    if (hz <= 0) {
        hz = sysconf(_SC_CLK_TCK);
        if (hz <= 0) {
            hz = 1000;
        }
    }

    // convert to centiseconds
    time = (time * 100 + (hz / 2)) / hz;

    char str[16];

    snprintf(str, sizeof(str), " %llu.%02u",
             time / 100, (unsigned)(time % 100));
    size_t offset = strlen(buffer);
    snprintf(buffer + offset, (len > offset) ? len - offset : 0,
             "%*s", (spc > offset) ? (int)(spc - offset) : 0, str);
}

// print permille as a percent
static void snprdec(char *buffer, size_t len, size_t spc, unsigned permille) {
    char str[16];

    snprintf(str, sizeof(str), " %u.%u%%", permille / 10, permille % 10);
    size_t offset = strlen(buffer);
    snprintf(buffer + offset, (len > offset) ? len - offset : 0,
             "%*s", (spc > offset) ? (int)(spc - offset) : 0, str);
}

void show_showtime(int pid, const char *name) {
    ON_DRY_RUN_RETURN();
    char path[255];
    char buffer[1023];
    int fd, ret, save_errno;

    memset(buffer, 0, sizeof(buffer));

    snprintf(path, sizeof(path), "/proc/%d/stat", pid);
    if ((fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY | O_CLOEXEC))) < 0) {
        printf("Failed to open '%s' (%s)\n", path, strerror(errno));
        return;
    }

    ret = TEMP_FAILURE_RETRY(read(fd, buffer, sizeof(buffer)));
    save_errno = errno;
    close(fd);

    if (ret < 0) {
        printf("Failed to read '%s' (%s)\n", path, strerror(save_errno));
        return;
    }

    // field 14 is utime
    // field 15 is stime
    // field 42 is iotime
    unsigned long long utime = 0, stime = 0, iotime = 0;
    if (sscanf(buffer,
               "%*u %*s %*s %*d %*d %*d %*d %*d %*d %*d %*d "
               "%*d %*d %llu %llu %*d %*d %*d %*d %*d %*d "
               "%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
               "%*d %*d %*d %*d %*d %*d %*d %*d %*d %llu ",
               &utime, &stime, &iotime) != 3) {
        return;
    }

    unsigned long long total = utime + stime;
    if (!total) {
        return;
    }

    unsigned permille = (iotime * 1000 + (total / 2)) / total;
    if (permille > 1000) {
        permille = 1000;
    }

    // try to beautify and stabilize columns at <80 characters
    snprintf(buffer, sizeof(buffer), "%-6d%s", pid, name);
    if ((name[0] != '[') || utime) {
        snprcent(buffer, sizeof(buffer), 57, utime);
    }
    snprcent(buffer, sizeof(buffer), 65, stime);
    if ((name[0] != '[') || iotime) {
        snprcent(buffer, sizeof(buffer), 73, iotime);
    }
    if (iotime) {
        snprdec(buffer, sizeof(buffer), 79, permille);
    }
    puts(buffer); // adds a trailing newline

    return;
}

void do_dmesg() {
    const char *title = "KERNEL LOG (dmesg)";
    DurationReporter duration_reporter(title);
    printf("------ %s ------\n", title);

    ON_DRY_RUN_RETURN();
    /* Get size of kernel buffer */
    int size = klogctl(KLOG_SIZE_BUFFER, NULL, 0);
    if (size <= 0) {
        printf("Unexpected klogctl return value: %d\n\n", size);
        return;
    }
    char *buf = (char *) malloc(size + 1);
    if (buf == NULL) {
        printf("memory allocation failed\n\n");
        return;
    }
    int retval = klogctl(KLOG_READ_ALL, buf, size);
    if (retval < 0) {
        printf("klogctl failure\n\n");
        free(buf);
        return;
    }
    buf[retval] = '\0';
    printf("%s\n\n", buf);
    free(buf);
    return;
}

void do_showmap(int pid, const char *name) {
    char title[255];
    char arg[255];

    snprintf(title, sizeof(title), "SHOW MAP %d (%s)", pid, name);
    snprintf(arg, sizeof(arg), "%d", pid);
    run_command(title, 10, SU_PATH, "root", "showmap", "-q", arg, NULL);
}

static int _dump_file_from_fd(const char *title, const char *path, int fd) {
    if (title) {
        printf("------ %s (%s", title, path);

        struct stat st;
        // Only show the modification time of non-device files.
        size_t path_len = strlen(path);
        if ((path_len < 6 || memcmp(path, "/proc/", 6)) &&
                (path_len < 5 || memcmp(path, "/sys/", 5)) &&
                (path_len < 3 || memcmp(path, "/d/", 3)) &&
                !fstat(fd, &st)) {
            char stamp[80];
            time_t mtime = st.st_mtime;
            strftime(stamp, sizeof(stamp), "%Y-%m-%d %H:%M:%S", localtime(&mtime));
            printf(": %s", stamp);
        }
        printf(") ------\n");
    }
    ON_DRY_RUN({ update_progress(WEIGHT_FILE); close(fd); return 0; });

    bool newline = false;
    fd_set read_set;
    struct timeval tm;
    while (1) {
        FD_ZERO(&read_set);
        FD_SET(fd, &read_set);
        /* Timeout if no data is read for 30 seconds. */
        tm.tv_sec = 30;
        tm.tv_usec = 0;
        uint64_t elapsed = DurationReporter::nanotime();
        int ret = TEMP_FAILURE_RETRY(select(fd + 1, &read_set, NULL, NULL, &tm));
        if (ret == -1) {
            printf("*** %s: select failed: %s\n", path, strerror(errno));
            newline = true;
            break;
        } else if (ret == 0) {
            elapsed = DurationReporter::nanotime() - elapsed;
            printf("*** %s: Timed out after %.3fs\n", path,
                   (float) elapsed / NANOS_PER_SEC);
            newline = true;
            break;
        } else {
            char buffer[65536];
            ssize_t bytes_read = TEMP_FAILURE_RETRY(read(fd, buffer, sizeof(buffer)));
            if (bytes_read > 0) {
                fwrite(buffer, bytes_read, 1, stdout);
                newline = (buffer[bytes_read-1] == '\n');
            } else {
                if (bytes_read == -1) {
                    printf("*** %s: Failed to read from fd: %s", path, strerror(errno));
                    newline = true;
                }
                break;
            }
        }
    }
    update_progress(WEIGHT_FILE);
    close(fd);

    if (!newline) printf("\n");
    if (title) printf("\n");
    return 0;
}

/* prints the contents of a file */
int dump_file(const char *title, const char *path) {
    DurationReporter duration_reporter(title);
    int fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY | O_NONBLOCK | O_CLOEXEC));
    if (fd < 0) {
        int err = errno;
        printf("*** %s: %s\n", path, strerror(err));
        if (title) printf("\n");
        return -1;
    }
    return _dump_file_from_fd(title, path, fd);
}

int read_file_as_long(const char *path, long int *output) {
    int fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY | O_NONBLOCK | O_CLOEXEC));
    if (fd < 0) {
        int err = errno;
        MYLOGE("Error opening file descriptor for %s: %s\n", path, strerror(err));
        return -1;
    }
    char buffer[50];
    ssize_t bytes_read = TEMP_FAILURE_RETRY(read(fd, buffer, sizeof(buffer)));
    if (bytes_read == -1) {
        MYLOGE("Error reading file %s: %s\n", path, strerror(errno));
        return -2;
    }
    if (bytes_read == 0) {
        MYLOGE("File %s is empty\n", path);
        return -3;
    }
    *output = atoi(buffer);
    return 0;
}

/* calls skip to gate calling dump_from_fd recursively
 * in the specified directory. dump_from_fd defaults to
 * dump_file_from_fd above when set to NULL. skip defaults
 * to false when set to NULL. dump_from_fd will always be
 * called with title NULL.
 */
int dump_files(const char *title, const char *dir,
        bool (*skip)(const char *path),
        int (*dump_from_fd)(const char *title, const char *path, int fd)) {
    DurationReporter duration_reporter(title);
    DIR *dirp;
    struct dirent *d;
    char *newpath = NULL;
    const char *slash = "/";
    int fd, retval = 0;

    if (title) {
        printf("------ %s (%s) ------\n", title, dir);
    }
    ON_DRY_RUN_RETURN(0);

    if (dir[strlen(dir) - 1] == '/') {
        ++slash;
    }
    dirp = opendir(dir);
    if (dirp == NULL) {
        retval = -errno;
        MYLOGE("%s: %s\n", dir, strerror(errno));
        return retval;
    }

    if (!dump_from_fd) {
        dump_from_fd = dump_file_from_fd;
    }
    for (; ((d = readdir(dirp))); free(newpath), newpath = NULL) {
        if ((d->d_name[0] == '.')
         && (((d->d_name[1] == '.') && (d->d_name[2] == '\0'))
          || (d->d_name[1] == '\0'))) {
            continue;
        }
        asprintf(&newpath, "%s%s%s%s", dir, slash, d->d_name,
                 (d->d_type == DT_DIR) ? "/" : "");
        if (!newpath) {
            retval = -errno;
            continue;
        }
        if (skip && (*skip)(newpath)) {
            continue;
        }
        if (d->d_type == DT_DIR) {
            int ret = dump_files(NULL, newpath, skip, dump_from_fd);
            if (ret < 0) {
                retval = ret;
            }
            continue;
        }
        fd = TEMP_FAILURE_RETRY(open(newpath, O_RDONLY | O_NONBLOCK | O_CLOEXEC));
        if (fd < 0) {
            retval = fd;
            printf("*** %s: %s\n", newpath, strerror(errno));
            continue;
        }
        (*dump_from_fd)(NULL, newpath, fd);
    }
    closedir(dirp);
    if (title) {
        printf("\n");
    }
    return retval;
}

/* fd must have been opened with the flag O_NONBLOCK. With this flag set,
 * it's possible to avoid issues where opening the file itself can get
 * stuck.
 */
int dump_file_from_fd(const char *title, const char *path, int fd) {
    ON_DRY_RUN_RETURN(0);
    int flags = fcntl(fd, F_GETFL);
    if (flags == -1) {
        printf("*** %s: failed to get flags on fd %d: %s\n", path, fd, strerror(errno));
        close(fd);
        return -1;
    } else if (!(flags & O_NONBLOCK)) {
        printf("*** %s: fd must have O_NONBLOCK set.\n", path);
        close(fd);
        return -1;
    }
    return _dump_file_from_fd(title, path, fd);
}

bool waitpid_with_timeout(pid_t pid, int timeout_seconds, int* status) {
    sigset_t child_mask, old_mask;
    sigemptyset(&child_mask);
    sigaddset(&child_mask, SIGCHLD);

    if (sigprocmask(SIG_BLOCK, &child_mask, &old_mask) == -1) {
        printf("*** sigprocmask failed: %s\n", strerror(errno));
        return false;
    }

    struct timespec ts;
    ts.tv_sec = timeout_seconds;
    ts.tv_nsec = 0;
    int ret = TEMP_FAILURE_RETRY(sigtimedwait(&child_mask, NULL, &ts));
    int saved_errno = errno;
    // Set the signals back the way they were.
    if (sigprocmask(SIG_SETMASK, &old_mask, NULL) == -1) {
        printf("*** sigprocmask failed: %s\n", strerror(errno));
        if (ret == 0) {
            return false;
        }
    }
    if (ret == -1) {
        errno = saved_errno;
        if (errno == EAGAIN) {
            errno = ETIMEDOUT;
        } else {
            printf("*** sigtimedwait failed: %s\n", strerror(errno));
        }
        return false;
    }

    pid_t child_pid = waitpid(pid, status, WNOHANG);
    if (child_pid != pid) {
        if (child_pid != -1) {
            printf("*** Waiting for pid %d, got pid %d instead\n", pid, child_pid);
        } else {
            printf("*** waitpid failed: %s\n", strerror(errno));
        }
        return false;
    }
    return true;
}

// TODO: refactor all those commands that convert args
void format_args(const char* command, const char *args[], std::string *string);

int run_command(const char *title, int timeout_seconds, const char *command, ...) {
    DurationReporter duration_reporter(title);
    fflush(stdout);

    const char *args[1024] = {command};
    size_t arg;
    va_list ap;
    va_start(ap, command);
    if (title) printf("------ %s (%s", title, command);
    bool null_terminated = false;
    for (arg = 1; arg < sizeof(args) / sizeof(args[0]); ++arg) {
        args[arg] = va_arg(ap, const char *);
        if (args[arg] == nullptr) {
            null_terminated = true;
            break;
        }
        // TODO: null_terminated check is not really working; line below would crash dumpstate if
        // nullptr is missing
        if (title) printf(" %s", args[arg]);
    }
    if (title) printf(") ------\n");
    fflush(stdout);
    if (!null_terminated) {
        // Fail now, otherwise execvp() call on run_command_always() might hang.
        std::string cmd;
        format_args(command, args, &cmd);
        MYLOGE("skipping command %s because its args were not NULL-terminated", cmd.c_str());
        return -1;
    }

    ON_DRY_RUN({ update_progress(timeout_seconds); va_end(ap); return 0; });

    int status = run_command_always(title, DONT_DROP_ROOT, NORMAL_STDOUT, timeout_seconds, args);
    va_end(ap);
    return status;
}

int run_command_as_shell(const char *title, int timeout_seconds, const char *command, ...) {
    DurationReporter duration_reporter(title);
    fflush(stdout);

    const char *args[1024] = {command};
    size_t arg;
    va_list ap;
    va_start(ap, command);
    if (title) printf("------ %s (%s", title, command);
    bool null_terminated = false;
    for (arg = 1; arg < sizeof(args) / sizeof(args[0]); ++arg) {
        args[arg] = va_arg(ap, const char *);
        if (args[arg] == nullptr) {
            null_terminated = true;
            break;
        }
        // TODO: null_terminated check is not really working; line below would crash dumpstate if
        // nullptr is missing
        if (title) printf(" %s", args[arg]);
    }
    if (title) printf(") ------\n");
    fflush(stdout);
    if (!null_terminated) {
        // Fail now, otherwise execvp() call on run_command_always() might hang.
        std::string cmd;
        format_args(command, args, &cmd);
        MYLOGE("skipping command %s because its args were not NULL-terminated", cmd.c_str());
        return -1;
    }

    ON_DRY_RUN({ update_progress(timeout_seconds); va_end(ap); return 0; });

    int status = run_command_always(title, DROP_ROOT, NORMAL_STDOUT, timeout_seconds, args);
    va_end(ap);
    return status;
}

/* forks a command and waits for it to finish */
int run_command_always(const char *title, RootMode root_mode, StdoutMode stdout_mode,
        int timeout_seconds, const char *args[]) {
    bool silent = (stdout_mode == REDIRECT_TO_STDERR);
    // TODO: need to check if args is null-terminated, otherwise execvp will crash dumpstate

    /* TODO: for now we're simplifying the progress calculation by using the timeout as the weight.
     * It's a good approximation for most cases, except when calling dumpsys, where its weight
     * should be much higher proportionally to its timeout. */
    int weight = timeout_seconds;

    const char *command = args[0];
    uint64_t start = DurationReporter::nanotime();
    pid_t pid = fork();

    /* handle error case */
    if (pid < 0) {
        if (!silent) printf("*** fork: %s\n", strerror(errno));
        MYLOGE("*** fork: %s\n", strerror(errno));
        return pid;
    }

    /* handle child case */
    if (pid == 0) {
        if (root_mode == DROP_ROOT && !drop_root_user()) {
        if (!silent) printf("*** fail todrop root before running %s: %s\n", command,
                strerror(errno));
            MYLOGE("*** could not drop root before running %s: %s\n", command, strerror(errno));
            return -1;
        }

        if (silent) {
            // Redirect stderr to stdout
            dup2(STDERR_FILENO, STDOUT_FILENO);
        }

        /* make sure the child dies when dumpstate dies */
        prctl(PR_SET_PDEATHSIG, SIGKILL);

        /* just ignore SIGPIPE, will go down with parent's */
        struct sigaction sigact;
        memset(&sigact, 0, sizeof(sigact));
        sigact.sa_handler = SIG_IGN;
        sigaction(SIGPIPE, &sigact, NULL);

        execvp(command, (char**) args);
        // execvp's result will be handled after waitpid_with_timeout() below, but if it failed,
        // it's safer to exit dumpstate.
        MYLOGD("execvp on command '%s' failed (error: %s)", command, strerror(errno));
        fflush(stdout);
        // Must call _exit (instead of exit), otherwise it will corrupt the zip file.
        _exit(EXIT_FAILURE);
    }

    /* handle parent case */
    int status;
    bool ret = waitpid_with_timeout(pid, timeout_seconds, &status);
    uint64_t elapsed = DurationReporter::nanotime() - start;
    std::string cmd; // used to log command and its args
    if (!ret) {
        if (errno == ETIMEDOUT) {
            format_args(command, args, &cmd);
            if (!silent) printf("*** command '%s' timed out after %.3fs (killing pid %d)\n",
            cmd.c_str(), (float) elapsed / NANOS_PER_SEC, pid);
            MYLOGE("command '%s' timed out after %.3fs (killing pid %d)\n", cmd.c_str(),
                   (float) elapsed / NANOS_PER_SEC, pid);
        } else {
            format_args(command, args, &cmd);
            if (!silent) printf("*** command '%s': Error after %.4fs (killing pid %d)\n",
            cmd.c_str(), (float) elapsed / NANOS_PER_SEC, pid);
            MYLOGE("command '%s': Error after %.4fs (killing pid %d)\n", cmd.c_str(),
                   (float) elapsed / NANOS_PER_SEC, pid);
        }
        kill(pid, SIGTERM);
        if (!waitpid_with_timeout(pid, 5, NULL)) {
            kill(pid, SIGKILL);
            if (!waitpid_with_timeout(pid, 5, NULL)) {
                if (!silent) printf("could not kill command '%s' (pid %d) even with SIGKILL.\n",
                        command, pid);
                MYLOGE("could not kill command '%s' (pid %d) even with SIGKILL.\n", command, pid);
            }
        }
        return -1;
    } else if (status) {
        format_args(command, args, &cmd);
        if (!silent) printf("*** command '%s' failed: %s\n", cmd.c_str(), strerror(errno));
        MYLOGE("command '%s' failed: %s\n", cmd.c_str(), strerror(errno));
        return -2;
    }

    if (WIFSIGNALED(status)) {
        if (!silent) printf("*** %s: Killed by signal %d\n", command, WTERMSIG(status));
        MYLOGE("*** %s: Killed by signal %d\n", command, WTERMSIG(status));
    } else if (WIFEXITED(status) && WEXITSTATUS(status) > 0) {
        if (!silent) printf("*** %s: Exit code %d\n", command, WEXITSTATUS(status));
        MYLOGE("*** %s: Exit code %d\n", command, WEXITSTATUS(status));
    }

    if (weight > 0) {
        update_progress(weight);
    }
    return status;
}

bool drop_root_user() {
    if (getgid() == AID_SHELL && getuid() == AID_SHELL) {
        MYLOGD("drop_root_user(): already running as Shell");
        return true;
    }
    /* ensure we will keep capabilities when we drop root */
    if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
        MYLOGE("prctl(PR_SET_KEEPCAPS) failed: %s\n", strerror(errno));
        return false;
    }

    gid_t groups[] = { AID_LOG, AID_SDCARD_R, AID_SDCARD_RW,
            AID_MOUNT, AID_INET, AID_NET_BW_STATS, AID_READPROC, AID_WAKELOCK,
            AID_BLUETOOTH };
    if (setgroups(sizeof(groups)/sizeof(groups[0]), groups) != 0) {
        MYLOGE("Unable to setgroups, aborting: %s\n", strerror(errno));
        return false;
    }
    if (setgid(AID_SHELL) != 0) {
        MYLOGE("Unable to setgid, aborting: %s\n", strerror(errno));
        return false;
    }
    if (setuid(AID_SHELL) != 0) {
        MYLOGE("Unable to setuid, aborting: %s\n", strerror(errno));
        return false;
    }

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

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

    return true;
}

void send_broadcast(const std::string& action, const std::vector<std::string>& args) {
    if (args.size() > 1000) {
        MYLOGE("send_broadcast: too many arguments (%d)\n", (int) args.size());
        return;
    }
    const char *am_args[1024] = { "/system/bin/am", "broadcast", "--user", "0", "-a",
                                  action.c_str() };
    size_t am_index = 5; // Starts at the index of last initial value above.
    for (const std::string& arg : args) {
        am_args[++am_index] = arg.c_str();
    }
    // Always terminate with NULL.
    am_args[am_index + 1] = NULL;
    std::string args_string;
    format_args(am_index + 1, am_args, &args_string);
    MYLOGD("send_broadcast command: %s\n", args_string.c_str());
    run_command_always(NULL, DROP_ROOT, REDIRECT_TO_STDERR, 20, am_args);
}

size_t num_props = 0;
static char* props[2000];

static void print_prop(const char *key, const char *name, void *user) {
    (void) user;
    if (num_props < sizeof(props) / sizeof(props[0])) {
        char buf[PROPERTY_KEY_MAX + PROPERTY_VALUE_MAX + 10];
        snprintf(buf, sizeof(buf), "[%s]: [%s]\n", key, name);
        props[num_props++] = strdup(buf);
    }
}

static int compare_prop(const void *a, const void *b) {
    return strcmp(*(char * const *) a, *(char * const *) b);
}

/* prints all the system properties */
void print_properties() {
    const char* title = "SYSTEM PROPERTIES";
    DurationReporter duration_reporter(title);
    printf("------ %s ------\n", title);
    ON_DRY_RUN_RETURN();
    size_t i;
    num_props = 0;
    property_list(print_prop, NULL);
    qsort(&props, num_props, sizeof(props[0]), compare_prop);

    for (i = 0; i < num_props; ++i) {
        fputs(props[i], stdout);
        free(props[i]);
    }
    printf("\n");
}

int open_socket(const char *service) {
    int s = android_get_control_socket(service);
    if (s < 0) {
        MYLOGE("android_get_control_socket(%s): %s\n", service, strerror(errno));
        exit(1);
    }
    fcntl(s, F_SETFD, FD_CLOEXEC);
    if (listen(s, 4) < 0) {
        MYLOGE("listen(control socket): %s\n", strerror(errno));
        exit(1);
    }

    struct sockaddr addr;
    socklen_t alen = sizeof(addr);
    int fd = accept(s, &addr, &alen);
    if (fd < 0) {
        MYLOGE("accept(control socket): %s\n", strerror(errno));
        exit(1);
    }

    return fd;
}

/* redirect output to a service control socket */
void redirect_to_socket(FILE *redirect, const char *service) {
    int fd = open_socket(service);
    fflush(redirect);
    dup2(fd, fileno(redirect));
    close(fd);
}

// TODO: should call is_valid_output_file and/or be merged into it.
void create_parent_dirs(const char *path) {
    char *chp = const_cast<char *> (path);

    /* skip initial slash */
    if (chp[0] == '/')
        chp++;

    /* create leading directories, if necessary */
    struct stat dir_stat;
    while (chp && chp[0]) {
        chp = strchr(chp, '/');
        if (chp) {
            *chp = 0;
            if (stat(path, &dir_stat) == -1 || !S_ISDIR(dir_stat.st_mode)) {
                MYLOGI("Creating directory %s\n", path);
                if (mkdir(path, 0770)) { /* drwxrwx--- */
                    MYLOGE("Unable to create directory %s: %s\n", path, strerror(errno));
                } else if (chown(path, AID_SHELL, AID_SHELL)) {
                    MYLOGE("Unable to change ownership of dir %s: %s\n", path, strerror(errno));
                }
            }
            *chp++ = '/';
        }
    }
}

/* redirect output to a file */
void redirect_to_file(FILE *redirect, char *path) {
    create_parent_dirs(path);

    int fd = TEMP_FAILURE_RETRY(open(path, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW,
                                     S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH));
    if (fd < 0) {
        MYLOGE("%s: %s\n", path, strerror(errno));
        exit(1);
    }

    TEMP_FAILURE_RETRY(dup2(fd, fileno(redirect)));
    close(fd);
}

static bool should_dump_native_traces(const char* path) {
    for (const char** p = native_processes_to_dump; *p; p++) {
        if (!strcmp(*p, path)) {
            return true;
        }
    }
    return false;
}

/* dump Dalvik and native stack traces, return the trace file location (NULL if none) */
const char *dump_traces() {
    DurationReporter duration_reporter("DUMP TRACES", NULL);
    ON_DRY_RUN_RETURN(NULL);
    const char* result = NULL;

    char traces_path[PROPERTY_VALUE_MAX] = "";
    property_get("dalvik.vm.stack-trace-file", traces_path, "");
    if (!traces_path[0]) return NULL;

    /* move the old traces.txt (if any) out of the way temporarily */
    char anr_traces_path[PATH_MAX];
    strlcpy(anr_traces_path, traces_path, sizeof(anr_traces_path));
    strlcat(anr_traces_path, ".anr", sizeof(anr_traces_path));
    if (rename(traces_path, anr_traces_path) && errno != ENOENT) {
        MYLOGE("rename(%s, %s): %s\n", traces_path, anr_traces_path, strerror(errno));
        return NULL;  // Can't rename old traces.txt -- no permission? -- leave it alone instead
    }

    /* create a new, empty traces.txt file to receive stack dumps */
    int fd = TEMP_FAILURE_RETRY(open(traces_path, O_CREAT | O_WRONLY | O_TRUNC | O_NOFOLLOW | O_CLOEXEC,
                                     0666));  /* -rw-rw-rw- */
    if (fd < 0) {
        MYLOGE("%s: %s\n", traces_path, strerror(errno));
        return NULL;
    }
    int chmod_ret = fchmod(fd, 0666);
    if (chmod_ret < 0) {
        MYLOGE("fchmod on %s failed: %s\n", traces_path, strerror(errno));
        close(fd);
        return NULL;
    }

    /* Variables below must be initialized before 'goto' statements */
    int dalvik_found = 0;
    int ifd, wfd = -1;

    /* walk /proc and kill -QUIT all Dalvik processes */
    DIR *proc = opendir("/proc");
    if (proc == NULL) {
        MYLOGE("/proc: %s\n", strerror(errno));
        goto error_close_fd;
    }

    /* use inotify to find when processes are done dumping */
    ifd = inotify_init();
    if (ifd < 0) {
        MYLOGE("inotify_init: %s\n", strerror(errno));
        goto error_close_fd;
    }

    wfd = inotify_add_watch(ifd, traces_path, IN_CLOSE_WRITE);
    if (wfd < 0) {
        MYLOGE("inotify_add_watch(%s): %s\n", traces_path, strerror(errno));
        goto error_close_ifd;
    }

    struct dirent *d;
    while ((d = readdir(proc))) {
        int pid = atoi(d->d_name);
        if (pid <= 0) continue;

        char path[PATH_MAX];
        char data[PATH_MAX];
        snprintf(path, sizeof(path), "/proc/%d/exe", pid);
        ssize_t len = readlink(path, data, sizeof(data) - 1);
        if (len <= 0) {
            continue;
        }
        data[len] = '\0';

        if (!strncmp(data, "/system/bin/app_process", strlen("/system/bin/app_process"))) {
            /* skip zygote -- it won't dump its stack anyway */
            snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
            int cfd = TEMP_FAILURE_RETRY(open(path, O_RDONLY | O_CLOEXEC));
            len = read(cfd, data, sizeof(data) - 1);
            close(cfd);
            if (len <= 0) {
                continue;
            }
            data[len] = '\0';
            if (!strncmp(data, "zygote", strlen("zygote"))) {
                continue;
            }

            ++dalvik_found;
            uint64_t start = DurationReporter::nanotime();
            if (kill(pid, SIGQUIT)) {
                MYLOGE("kill(%d, SIGQUIT): %s\n", pid, strerror(errno));
                continue;
            }

            /* wait for the writable-close notification from inotify */
            struct pollfd pfd = { ifd, POLLIN, 0 };
            int ret = poll(&pfd, 1, 5000);  /* 5 sec timeout */
            if (ret < 0) {
                MYLOGE("poll: %s\n", strerror(errno));
            } else if (ret == 0) {
                MYLOGE("warning: timed out dumping pid %d\n", pid);
            } else {
                struct inotify_event ie;
                read(ifd, &ie, sizeof(ie));
            }

            if (lseek(fd, 0, SEEK_END) < 0) {
                MYLOGE("lseek: %s\n", strerror(errno));
            } else {
                dprintf(fd, "[dump dalvik stack %d: %.3fs elapsed]\n",
                        pid, (float)(DurationReporter::nanotime() - start) / NANOS_PER_SEC);
            }
        } else if (should_dump_native_traces(data)) {
            /* dump native process if appropriate */
            if (lseek(fd, 0, SEEK_END) < 0) {
                MYLOGE("lseek: %s\n", strerror(errno));
            } else {
                static uint16_t timeout_failures = 0;
                uint64_t start = DurationReporter::nanotime();

                /* If 3 backtrace dumps fail in a row, consider debuggerd dead. */
                if (timeout_failures == 3) {
                    dprintf(fd, "too many stack dump failures, skipping...\n");
                } else if (dump_backtrace_to_file_timeout(pid, fd, 20) == -1) {
                    dprintf(fd, "dumping failed, likely due to a timeout\n");
                    timeout_failures++;
                } else {
                    timeout_failures = 0;
                }
                dprintf(fd, "[dump native stack %d: %.3fs elapsed]\n",
                        pid, (float)(DurationReporter::nanotime() - start) / NANOS_PER_SEC);
            }
        }
    }

    if (dalvik_found == 0) {
        MYLOGE("Warning: no Dalvik processes found to dump stacks\n");
    }

    static char dump_traces_path[PATH_MAX];
    strlcpy(dump_traces_path, traces_path, sizeof(dump_traces_path));
    strlcat(dump_traces_path, ".bugreport", sizeof(dump_traces_path));
    if (rename(traces_path, dump_traces_path)) {
        MYLOGE("rename(%s, %s): %s\n", traces_path, dump_traces_path, strerror(errno));
        goto error_close_ifd;
    }
    result = dump_traces_path;

    /* replace the saved [ANR] traces.txt file */
    rename(anr_traces_path, traces_path);

error_close_ifd:
    close(ifd);
error_close_fd:
    close(fd);
    return result;
}

void dump_route_tables() {
    DurationReporter duration_reporter("DUMP ROUTE TABLES");
    ON_DRY_RUN_RETURN();
    const char* const RT_TABLES_PATH = "/data/misc/net/rt_tables";
    dump_file("RT_TABLES", RT_TABLES_PATH);
    FILE* fp = fopen(RT_TABLES_PATH, "re");
    if (!fp) {
        printf("*** %s: %s\n", RT_TABLES_PATH, strerror(errno));
        return;
    }
    char table[16];
    // Each line has an integer (the table number), a space, and a string (the table name). We only
    // need the table number. It's a 32-bit unsigned number, so max 10 chars. Skip the table name.
    // Add a fixed max limit so this doesn't go awry.
    for (int i = 0; i < 64 && fscanf(fp, " %10s %*s", table) == 1; ++i) {
        run_command("ROUTE TABLE IPv4", 10, "ip", "-4", "route", "show", "table", table, NULL);
        run_command("ROUTE TABLE IPv6", 10, "ip", "-6", "route", "show", "table", table, NULL);
    }
    fclose(fp);
}

/* overall progress */
int progress = 0;
int do_update_progress = 0; // Set by dumpstate.cpp
int weight_total = WEIGHT_TOTAL;

// TODO: make this function thread safe if sections are generated in parallel.
void update_progress(int delta) {
    if (!do_update_progress) return;

    progress += delta;

    char key[PROPERTY_KEY_MAX];
    char value[PROPERTY_VALUE_MAX];

    // adjusts max on the fly
    if (progress > weight_total) {
        int new_total = weight_total * 1.2;
        MYLOGD("Adjusting total weight from %d to %d\n", weight_total, new_total);
        weight_total = new_total;
        snprintf(key, sizeof(key), "dumpstate.%d.max", getpid());
        snprintf(value, sizeof(value), "%d", weight_total);
        int status = property_set(key, value);
        if (status) {
            MYLOGE("Could not update max weight by setting system property %s to %s: %d\n",
                    key, value, status);
        }
    }

    snprintf(key, sizeof(key), "dumpstate.%d.progress", getpid());
    snprintf(value, sizeof(value), "%d", progress);

    if (progress % 100 == 0) {
        // We don't want to spam logcat, so only log multiples of 100.
        MYLOGD("Setting progress (%s): %s/%d\n", key, value, weight_total);
    } else {
        // stderr is ignored on normal invocations, but useful when calling /system/bin/dumpstate
        // directly for debuggging.
        fprintf(stderr, "Setting progress (%s): %s/%d\n", key, value, weight_total);
    }

    if (control_socket_fd >= 0) {
        dprintf(control_socket_fd, "PROGRESS:%d/%d\n", progress, weight_total);
        fsync(control_socket_fd);
    }

    int status = property_set(key, value);
    if (status) {
        MYLOGE("Could not update progress by setting system property %s to %s: %d\n",
                key, value, status);
    }
}

void take_screenshot(const std::string& path) {
    const char *args[] = { "/system/bin/screencap", "-p", path.c_str(), NULL };
    run_command_always(NULL, DONT_DROP_ROOT, REDIRECT_TO_STDERR, 10, args);
}

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

bool is_dir(const char* pathname) {
    struct stat info;
    if (stat(pathname, &info) == -1) {
        return false;
    }
    return S_ISDIR(info.st_mode);
}

time_t get_mtime(int fd, time_t default_mtime) {
    struct stat info;
    if (fstat(fd, &info) == -1) {
        return default_mtime;
    }
    return info.st_mtime;
}

void dump_emmc_ecsd(const char *ext_csd_path) {
    // List of interesting offsets
    struct hex {
        char str[2];
    };
    static const size_t EXT_CSD_REV = 192 * sizeof(hex);
    static const size_t EXT_PRE_EOL_INFO = 267 * sizeof(hex);
    static const size_t EXT_DEVICE_LIFE_TIME_EST_TYP_A = 268 * sizeof(hex);
    static const size_t EXT_DEVICE_LIFE_TIME_EST_TYP_B = 269 * sizeof(hex);

    std::string buffer;
    if (!android::base::ReadFileToString(ext_csd_path, &buffer)) {
        return;
    }

    printf("------ %s Extended CSD ------\n", ext_csd_path);

    if (buffer.length() < (EXT_CSD_REV + sizeof(hex))) {
        printf("*** %s: truncated content %zu\n\n", ext_csd_path, buffer.length());
        return;
    }

    int ext_csd_rev = 0;
    std::string sub = buffer.substr(EXT_CSD_REV, sizeof(hex));
    if (sscanf(sub.c_str(), "%2x", &ext_csd_rev) != 1) {
        printf("*** %s: EXT_CSD_REV parse error \"%s\"\n\n",
               ext_csd_path, sub.c_str());
        return;
    }

    static const char *ver_str[] = {
        "4.0", "4.1", "4.2", "4.3", "Obsolete", "4.41", "4.5", "5.0"
    };
    printf("rev 1.%d (MMC %s)\n",
           ext_csd_rev,
           (ext_csd_rev < (int)(sizeof(ver_str) / sizeof(ver_str[0]))) ?
               ver_str[ext_csd_rev] :
               "Unknown");
    if (ext_csd_rev < 7) {
        printf("\n");
        return;
    }

    if (buffer.length() < (EXT_PRE_EOL_INFO + sizeof(hex))) {
        printf("*** %s: truncated content %zu\n\n", ext_csd_path, buffer.length());
        return;
    }

    int ext_pre_eol_info = 0;
    sub = buffer.substr(EXT_PRE_EOL_INFO, sizeof(hex));
    if (sscanf(sub.c_str(), "%2x", &ext_pre_eol_info) != 1) {
        printf("*** %s: PRE_EOL_INFO parse error \"%s\"\n\n",
               ext_csd_path, sub.c_str());
        return;
    }

    static const char *eol_str[] = {
        "Undefined",
        "Normal",
        "Warning (consumed 80% of reserve)",
        "Urgent (consumed 90% of reserve)"
    };
    printf("PRE_EOL_INFO %d (MMC %s)\n",
           ext_pre_eol_info,
           eol_str[(ext_pre_eol_info < (int)
                       (sizeof(eol_str) / sizeof(eol_str[0]))) ?
                           ext_pre_eol_info : 0]);

    for (size_t lifetime = EXT_DEVICE_LIFE_TIME_EST_TYP_A;
            lifetime <= EXT_DEVICE_LIFE_TIME_EST_TYP_B;
            lifetime += sizeof(hex)) {
        int ext_device_life_time_est;
        static const char *est_str[] = {
            "Undefined",
            "0-10% of device lifetime used",
            "10-20% of device lifetime used",
            "20-30% of device lifetime used",
            "30-40% of device lifetime used",
            "40-50% of device lifetime used",
            "50-60% of device lifetime used",
            "60-70% of device lifetime used",
            "70-80% of device lifetime used",
            "80-90% of device lifetime used",
            "90-100% of device lifetime used",
            "Exceeded the maximum estimated device lifetime",
        };

        if (buffer.length() < (lifetime + sizeof(hex))) {
            printf("*** %s: truncated content %zu\n", ext_csd_path, buffer.length());
            break;
        }

        ext_device_life_time_est = 0;
        sub = buffer.substr(lifetime, sizeof(hex));
        if (sscanf(sub.c_str(), "%2x", &ext_device_life_time_est) != 1) {
            printf("*** %s: DEVICE_LIFE_TIME_EST_TYP_%c parse error \"%s\"\n",
                   ext_csd_path,
                   (unsigned)((lifetime - EXT_DEVICE_LIFE_TIME_EST_TYP_A) /
                              sizeof(hex)) + 'A',
                   sub.c_str());
            continue;
        }
        printf("DEVICE_LIFE_TIME_EST_TYP_%c %d (MMC %s)\n",
               (unsigned)((lifetime - EXT_DEVICE_LIFE_TIME_EST_TYP_A) /
                          sizeof(hex)) + 'A',
               ext_device_life_time_est,
               est_str[(ext_device_life_time_est < (int)
                           (sizeof(est_str) / sizeof(est_str[0]))) ?
                               ext_device_life_time_est : 0]);
    }

    printf("\n");
}

// TODO: refactor all those commands that convert args
void format_args(int argc, const char *argv[], std::string *args) {
    LOG_ALWAYS_FATAL_IF(args == nullptr);
    for (int i = 0; i < argc; i++) {
        args->append(argv[i]);
        if (i < argc -1) {
          args->append(" ");
        }
    }
}
void format_args(const char* command, const char *args[], std::string *string) {
    LOG_ALWAYS_FATAL_IF(args == nullptr || command == nullptr);
    string->append(command);
    if (args[0] == nullptr) return;
    string->append(" ");

    for (int arg = 1; arg <= 1000; ++arg) {
        if (args[arg] == nullptr) return;
        string->append(args[arg]);
        if (args[arg+1] != nullptr) {
            string->append(" ");
        }
    }
    // TODO: not really working: if NULL is missing, it will crash dumpstate.
    MYLOGE("internal error: missing NULL entry on %s", string->c_str());
}