builtins.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 <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <linux/kd.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <linux/if.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/resource.h>

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

#include <private/android_filesystem_config.h>

void add_environment(const char *name, const char *value);

extern int init_module(void *, unsigned long, const char *);

static int write_file(const char *path, const char *value)
{
    int fd, ret, len;

    fd = open(path, O_WRONLY|O_CREAT, 0622);

    if (fd < 0)
        return -1;

    len = strlen(value);

    do {
        ret = write(fd, value, len);
    } while (ret < 0 && errno == EINTR);

    close(fd);
    if (ret < 0) {
        return -1;
    } else {
        return 0;
    }
}

static int insmod(const char *filename)
{
    void *module;
    unsigned size;
    int ret;

    module = read_file(filename, &size);
    if (!module)
        return -1;

    ret = init_module(module, size, "");

    free(module);

    return ret;
}

static int setkey(struct kbentry *kbe)
{
    int fd, ret;

    fd = open("/dev/tty0", O_RDWR | O_SYNC);
    if (fd < 0)
        return -1;

    ret = ioctl(fd, KDSKBENT, kbe);

    close(fd);
    return ret;
}

static int __ifupdown(const char *interface, int up)
{
    struct ifreq ifr;
    int s, ret;

    strlcpy(ifr.ifr_name, interface, IFNAMSIZ);

    s = socket(AF_INET, SOCK_DGRAM, 0);
    if (s < 0)
        return -1;

    ret = ioctl(s, SIOCGIFFLAGS, &ifr);
    if (ret < 0) {
        goto done;
    }

    if (up)
        ifr.ifr_flags |= IFF_UP;
    else
        ifr.ifr_flags &= ~IFF_UP;

    ret = ioctl(s, SIOCSIFFLAGS, &ifr);
    
done:
    close(s);
    return ret;
}

static void service_start_if_not_disabled(struct service *svc)
{
    if (!(svc->flags & SVC_DISABLED)) {
        service_start(svc);
    }
}

int do_class_start(int nargs, char **args)
{
        /* Starting a class does not start services
         * which are explicitly disabled.  They must
         * be started individually.
         */
    service_for_each_class(args[1], service_start_if_not_disabled);
    return 0;
}

int do_class_stop(int nargs, char **args)
{
    service_for_each_class(args[1], service_stop);
    return 0;
}

int do_domainname(int nargs, char **args)
{
    return write_file("/proc/sys/kernel/domainname", args[1]);
}

int do_exec(int nargs, char **args)
{
    return -1;
}

int do_export(int nargs, char **args)
{
    add_environment(args[1], args[2]);
    return 0;
}

int do_hostname(int nargs, char **args)
{
    return write_file("/proc/sys/kernel/hostname", args[1]);
}

int do_ifup(int nargs, char **args)
{
    return __ifupdown(args[1], 1);
}

int do_insmod(int nargs, char **args)
{
    return insmod(args[1]);
}

int do_import(int nargs, char **args)
{
    return -1;
}

int do_mkdir(int nargs, char **args)
{
    mode_t mode = 0755;

    /* mkdir <path> [mode] [owner] [group] */

    if (nargs >= 3) {
        mode = strtoul(args[2], 0, 8);
    }

    if (mkdir(args[1], mode)) {
        return -errno;
    }

    if (nargs >= 4) {
        uid_t uid = decode_uid(args[3]);
        gid_t gid = -1;

        if (nargs == 5) {
            gid = decode_uid(args[4]);
        }

        if (chown(args[1], uid, gid)) {
            return -errno;
        }
    }

    return 0;
}

static struct {
    const char *name;
    unsigned flag;
} mount_flags[] = {
    { "noatime",    MS_NOATIME },
    { "nosuid",     MS_NOSUID },
    { "nodev",      MS_NODEV },
    { "nodiratime", MS_NODIRATIME },
    { "ro",         MS_RDONLY },
    { "rw",         0 },
    { "remount",    MS_REMOUNT },
    { "defaults",   0 },
    { 0,            0 },
};

/* mount <type> <device> <path> <flags ...> <options> */
int do_mount(int nargs, char **args)
{
    char tmp[64];
    char *source;
    char *options = NULL;
    unsigned flags = 0;
    int n, i;

    for (n = 4; n < nargs; n++) {
        for (i = 0; mount_flags[i].name; i++) {
            if (!strcmp(args[n], mount_flags[i].name)) {
                flags |= mount_flags[i].flag;
                break;
            }
        }

        /* if our last argument isn't a flag, wolf it up as an option string */
        if (n + 1 == nargs && !mount_flags[i].name)
            options = args[n];
    }

    source = args[2];
    if (!strncmp(source, "mtd@", 4)) {
        n = mtd_name_to_number(source + 4);
        if (n >= 0) {
            sprintf(tmp, "/dev/block/mtdblock%d", n);
            source = tmp;
        }
    }
    return mount(source, args[3], args[1], flags, options);
}

int do_setkey(int nargs, char **args)
{
    struct kbentry kbe;
    kbe.kb_table = strtoul(args[1], 0, 0);
    kbe.kb_index = strtoul(args[2], 0, 0);
    kbe.kb_value = strtoul(args[3], 0, 0);
    return setkey(&kbe);
}

int do_setprop(int nargs, char **args)
{
    property_set(args[1], args[2]);
    return 0;
}

int do_setrlimit(int nargs, char **args)
{
    struct rlimit limit;
    int resource;
    resource = atoi(args[1]);
    limit.rlim_cur = atoi(args[2]);
    limit.rlim_max = atoi(args[3]);
    return setrlimit(resource, &limit);
}

int do_start(int nargs, char **args)
{
    struct service *svc;
    svc = service_find_by_name(args[1]);
    if (svc) {
        service_start(svc);
    }
    return 0;
}

int do_stop(int nargs, char **args)
{
    struct service *svc;
    svc = service_find_by_name(args[1]);
    if (svc) {
        service_stop(svc);
    }
    return 0;
}

int do_restart(int nargs, char **args)
{
    struct service *svc;
    svc = service_find_by_name(args[1]);
    if (svc) {
        service_stop(svc);
        service_start(svc);
    }
    return 0;
}

int do_trigger(int nargs, char **args)
{
    return 0;
}

int do_symlink(int nargs, char **args)
{
    return symlink(args[1], args[2]);
}

int do_write(int nargs, char **args)
{
    return write_file(args[1], args[2]);
}

int do_chown(int nargs, char **args) {
    /* GID is optional. */
    if (nargs == 3) {
        if (chown(args[2], decode_uid(args[1]), -1) < 0)
            return -errno;
    } else if (nargs == 4) {
        if (chown(args[3], decode_uid(args[1]), decode_uid(args[2])))
            return -errno;
    } else {
        return -1;
    }
    return 0;
}

static mode_t get_mode(const char *s) {
    mode_t mode = 0;
    while (*s) {
        if (*s >= '0' && *s <= '7') {
            mode = (mode<<3) | (*s-'0');
        } else {
            return -1;
        }
        s++;
    }
    return mode;
}

int do_chmod(int nargs, char **args) {
    mode_t mode = get_mode(args[1]);
    if (chmod(args[2], mode) < 0) {
        return -errno;
    }
    return 0;
}

int do_loglevel(int nargs, char **args) {
    if (nargs == 2) {
        log_set_level(atoi(args[1]));
        return 0;
    }
    return -1;
}

int do_device(int nargs, char **args) {
    int len;
    char tmp[64];
    char *source = args[1];
    int prefix = 0;

    if (nargs != 5)
        return -1;
    /* Check for wildcard '*' at the end which indicates a prefix. */
    len = strlen(args[1]) - 1;
    if (args[1][len] == '*') {
        args[1][len] = '\0';
        prefix = 1;
    }
    /* If path starts with mtd@ lookup the mount number. */
    if (!strncmp(source, "mtd@", 4)) {
        int n = mtd_name_to_number(source + 4);
        if (n >= 0) {
            snprintf(tmp, sizeof(tmp), "/dev/mtd/mtd%d", n);
            source = tmp;
        }
    }
    add_devperms_partners(source, get_mode(args[2]), decode_uid(args[3]),
                          decode_uid(args[4]), prefix);
    return 0;
}