init.c

Android 一些工具

/*
 * 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <ctype.h>
#include <signal.h>
#include <sys/wait.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/poll.h>
#include <time.h>
#include <errno.h>
#include <stdarg.h>
#include <mtd/mtd-user.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/reboot.h>

#include <cutils/sockets.h>
#include <termios.h>
#include <linux/kd.h>

#include <sys/system_properties.h>

#include "devices.h"
#include "init.h"
#include "property_service.h"

#ifndef BOOTCHART
# define  BOOTCHART  0
#endif

static int property_triggers_enabled = 0;

#if BOOTCHART
static int   bootchart_count;
extern int   bootchart_init(void);
extern int   bootchart_step(void);
extern void  bootchart_finish(void);
# define BOOTCHART_POLLING_MS   200 /* polling period in ms */
# define BOOTCHART_MAX_TIME_MS  (2*60*1000) /* max polling time from boot */
# define BOOTCHART_MAX_COUNT    (BOOTCHART_MAX_TIME_MS/BOOTCHART_POLLING_MS)
#endif

static char console[32];
static char serialno[32];
static char bootmode[32];
static char baseband[32];
static char carrier[32];
static char bootloader[32];
static char hardware[32];
static unsigned revision = 0;
static char qemu[32];

static void drain_action_queue(void);

static void notify_service_state(const char *name, const char *state)
{
    char pname[PROP_NAME_MAX];
    int len = strlen(name);
    if ((len + 10) > PROP_NAME_MAX)
        return;
    snprintf(pname, sizeof(pname), "init.svc.%s", name);
    property_set(pname, state);
}

static int have_console;
static char *console_name = "/dev/console";
static time_t process_needs_restart;

static const char *ENV[32];

/* add_environment - add "key=value" to the current environment */
int add_environment(const char *key, const char *val)
{
    int n;
 
    for (n = 0; n < 31; n++) {
        if (!ENV[n]) {
            size_t len = strlen(key) + strlen(val) + 2;
            char *entry = malloc(len);
            snprintf(entry, len, "%s=%s", key, val);
            ENV[n] = entry;
            return 0;
        }
    }

    return 1;
}

static void zap_stdio(void)
{
    int fd;
    fd = open("/dev/null", O_RDWR);
    dup2(fd, 0);
    dup2(fd, 1);
    dup2(fd, 2);
    close(fd);
}

static void open_console()
{
    int fd;
    if ((fd = open(console_name, O_RDWR)) < 0) {
        fd = open("/dev/null", O_RDWR);
    }
    dup2(fd, 0);
    dup2(fd, 1);
    dup2(fd, 2);
    close(fd);
}

/*
 * gettime() - returns the time in seconds of the system's monotonic clock or
 * zero on error.
 */
static time_t gettime(void)
{
    struct timespec ts;
    int ret;

    ret = clock_gettime(CLOCK_MONOTONIC, &ts);
    if (ret < 0) {
        ERROR("clock_gettime(CLOCK_MONOTONIC) failed: %s\n", strerror(errno));
        return 0;
    }

    return ts.tv_sec;
}

static void publish_socket(const char *name, int fd)
{
    char key[64] = ANDROID_SOCKET_ENV_PREFIX;
    char val[64];

    strlcpy(key + sizeof(ANDROID_SOCKET_ENV_PREFIX) - 1,
            name,
            sizeof(key) - sizeof(ANDROID_SOCKET_ENV_PREFIX));
    snprintf(val, sizeof(val), "%d", fd);
    add_environment(key, val);

    /* make sure we don't close-on-exec */
    fcntl(fd, F_SETFD, 0);
}

void service_start(struct service *svc)
{
    struct stat s;
    pid_t pid;
    int needs_console;
    int n;

        /* starting a service removes it from the disabled
         * state and immediately takes it out of the restarting
         * state if it was in there
         */
    svc->flags &= (~(SVC_DISABLED|SVC_RESTARTING));
    svc->time_started = 0;
    
        /* running processes require no additional work -- if
         * they're in the process of exiting, we've ensured
         * that they will immediately restart on exit, unless
         * they are ONESHOT
         */
    if (svc->flags & SVC_RUNNING) {
        return;
    }

    needs_console = (svc->flags & SVC_CONSOLE) ? 1 : 0;
    if (needs_console && (!have_console)) {
        ERROR("service '%s' requires console\n", svc->name);
        svc->flags |= SVC_DISABLED;
        return;
    }

    if (stat(svc->args[0], &s) != 0) {
        ERROR("cannot find '%s', disabling '%s'\n", svc->args[0], svc->name);
        svc->flags |= SVC_DISABLED;
        return;
    }

    NOTICE("starting '%s'\n", svc->name);

    pid = fork();

    if (pid == 0) {
        struct socketinfo *si;
        struct svcenvinfo *ei;
        char tmp[32];
        int fd, sz;

        get_property_workspace(&fd, &sz);
        sprintf(tmp, "%d,%d", dup(fd), sz);
        add_environment("ANDROID_PROPERTY_WORKSPACE", tmp);

        for (ei = svc->envvars; ei; ei = ei->next)
            add_environment(ei->name, ei->value);

        for (si = svc->sockets; si; si = si->next) {
            int s = create_socket(si->name,
                                  !strcmp(si->type, "dgram") ? 
                                  SOCK_DGRAM : SOCK_STREAM,
                                  si->perm, si->uid, si->gid);
            if (s >= 0) {
                publish_socket(si->name, s);
            }
        }

        if (needs_console) {
            setsid();
            open_console();
        } else {
            zap_stdio();
        }

#if 0
        for (n = 0; svc->args[n]; n++) {
            INFO("args[%d] = '%s'\n", n, svc->args[n]);
        }
        for (n = 0; ENV[n]; n++) {
            INFO("env[%d] = '%s'\n", n, ENV[n]);
        }
#endif

        setpgid(0, getpid());

	/* as requested, set our gid, supplemental gids, and uid */
        if (svc->gid) {
            setgid(svc->gid);
        }
        if (svc->nr_supp_gids) {
            setgroups(svc->nr_supp_gids, svc->supp_gids);
        }
        if (svc->uid) {
            setuid(svc->uid);
        }

        execve(svc->args[0], (char**) svc->args, (char**) ENV);
        _exit(127);
    }

    if (pid < 0) {
        ERROR("failed to start '%s'\n", svc->name);
        svc->pid = 0;
        return;
    }

    svc->time_started = gettime();
    svc->pid = pid;
    svc->flags |= SVC_RUNNING;

    notify_service_state(svc->name, "running");
}

void service_stop(struct service *svc)
{
        /* we are no longer running, nor should we
         * attempt to restart
         */
    svc->flags &= (~(SVC_RUNNING|SVC_RESTARTING));

        /* if the service has not yet started, prevent
         * it from auto-starting with its class
         */
    svc->flags |= SVC_DISABLED;

    if (svc->pid) {
        NOTICE("service '%s' is being killed\n", svc->name);
        kill(-svc->pid, SIGTERM);
        notify_service_state(svc->name, "stopping");
    } else {
        notify_service_state(svc->name, "stopped");
    }
}

void property_changed(const char *name, const char *value)
{
    if (property_triggers_enabled) {
        queue_property_triggers(name, value);
        drain_action_queue();
    }
}

#define CRITICAL_CRASH_THRESHOLD    4       /* if we crash >4 times ... */
#define CRITICAL_CRASH_WINDOW       (4*60)  /* ... in 4 minutes, goto recovery*/

static int wait_for_one_process(int block)
{
    pid_t pid;
    int status;
    struct service *svc;
    struct socketinfo *si;
    time_t now;
    struct listnode *node;
    struct command *cmd;

    while ( (pid = waitpid(-1, &status, block ? 0 : WNOHANG)) == -1 && errno == EINTR );
    if (pid <= 0) return -1;
    INFO("waitpid returned pid %d, status = %08x\n", pid, status);

    svc = service_find_by_pid(pid);
    if (!svc) {
        ERROR("untracked pid %d exited\n", pid);
        return 0;
    }

    NOTICE("process '%s', pid %d exited\n", svc->name, pid);

    if (!(svc->flags & SVC_ONESHOT)) {
        kill(-pid, SIGKILL);
        NOTICE("process '%s' killing any children in process group\n", svc->name);
    }

    /* remove any sockets we may have created */
    for (si = svc->sockets; si; si = si->next) {
        char tmp[128];
        snprintf(tmp, sizeof(tmp), ANDROID_SOCKET_DIR"/%s", si->name);
        unlink(tmp);
    }

    svc->pid = 0;
    svc->flags &= (~SVC_RUNNING);

        /* oneshot processes go into the disabled state on exit */
    if (svc->flags & SVC_ONESHOT) {
        svc->flags |= SVC_DISABLED;
    }

        /* disabled processes do not get restarted automatically */
    if (svc->flags & SVC_DISABLED) {
        notify_service_state(svc->name, "stopped");
        return 0;
    }

    now = gettime();
    if (svc->flags & SVC_CRITICAL) {
        if (svc->time_crashed + CRITICAL_CRASH_WINDOW >= now) {
            if (++svc->nr_crashed > CRITICAL_CRASH_THRESHOLD) {
                ERROR("critical process '%s' exited %d times in %d minutes; "
                      "rebooting into recovery mode\n", svc->name,
                      CRITICAL_CRASH_THRESHOLD, CRITICAL_CRASH_WINDOW / 60);
                sync();
                __reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2,
                         LINUX_REBOOT_CMD_RESTART2, "recovery");
                return 0;
            }
        } else {
            svc->time_crashed = now;
            svc->nr_crashed = 1;
        }
    }

    /* Execute all onrestart commands for this service. */
    list_for_each(node, &svc->onrestart.commands) {
        cmd = node_to_item(node, struct command, clist);
        cmd->func(cmd->nargs, cmd->args);
    }
    svc->flags |= SVC_RESTARTING;
    notify_service_state(svc->name, "restarting");
    return 0;
}

static void restart_service_if_needed(struct service *svc)
{
    time_t next_start_time = svc->time_started + 5;

    if (next_start_time <= gettime()) {
        svc->flags &= (~SVC_RESTARTING);
        service_start(svc);
        return;
    }

    if ((next_start_time < process_needs_restart) ||
        (process_needs_restart == 0)) {
        process_needs_restart = next_start_time;
    }
}

static void restart_processes()
{
    process_needs_restart = 0;
    service_for_each_flags(SVC_RESTARTING,
                           restart_service_if_needed);
}

static int signal_fd = -1;

static void sigchld_handler(int s)
{
    write(signal_fd, &s, 1);
}

static void msg_start(const char *name)
{
    struct service *svc = service_find_by_name(name);
    
    if (svc) {
        service_start(svc);
    } else {
        ERROR("no such service '%s'\n", name);
    }
}

static void msg_stop(const char *name)
{
    struct service *svc = service_find_by_name(name);

    if (svc) {
        service_stop(svc);
    } else {
        ERROR("no such service '%s'\n");
    }
}

void handle_control_message(const char *msg, const char *arg)
{
    if (!strcmp(msg,"start")) {
        msg_start(arg);
    } else if (!strcmp(msg,"stop")) {
        msg_stop(arg);
    } else {
        ERROR("unknown control msg '%s'\n", msg);
    }
}

#define MAX_MTD_PARTITIONS 16

static struct {