libcutils/fs_config.c

/*
 * Copyright (C) 2007 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.
 */

/* This file is used to define the properties of the filesystem
** images generated by build tools (mkbootfs and mkyaffs2image) and
** by the device side of adb.
*/

#include <stdint.h>
#include <string.h>
#include <sys/stat.h>

#include <private/android_filesystem_config.h>

/* Rules for directories.
** These rules are applied based on "first match", so they
** should start with the most specific path and work their
** way up to the root.
*/

static const struct fs_path_config android_dirs[] = {
    { 00770, AID_SYSTEM, AID_CACHE,  0, "cache" },
    { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app" },
    { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private" },
    { 00771, AID_ROOT,   AID_ROOT,   0, "data/dalvik-cache" },
    { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/data" },
    { 00771, AID_SHELL,  AID_SHELL,  0, "data/local/tmp" },
    { 00771, AID_SHELL,  AID_SHELL,  0, "data/local" },
    { 01771, AID_SYSTEM, AID_MISC,   0, "data/misc" },
    { 00770, AID_DHCP,   AID_DHCP,   0, "data/misc/dhcp" },
    { 00771, AID_SHARED_RELRO, AID_SHARED_RELRO, 0, "data/misc/shared_relro" },
    { 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media" },
    { 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/Music" },
    { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data" },
    { 00750, AID_ROOT,   AID_SHELL,  0, "sbin" },
    { 00755, AID_ROOT,   AID_SHELL,  0, "system/bin" },
    { 00755, AID_ROOT,   AID_SHELL,  0, "system/vendor" },
    { 00755, AID_ROOT,   AID_SHELL,  0, "system/xbin" },
    { 00755, AID_ROOT,   AID_ROOT,   0, "system/etc/ppp" },
    { 00755, AID_ROOT,   AID_SHELL,  0, "vendor" },
    { 00777, AID_ROOT,   AID_ROOT,   0, "sdcard" },
    { 00755, AID_ROOT,   AID_ROOT,   0, 0 },
};

/* Rules for files.
** These rules are applied based on "first match", so they
** should start with the most specific path and work their
** way up to the root. Prefixes ending in * denotes wildcard
** and will allow partial matches.
*/
static const struct fs_path_config android_files[] = {
    { 00440, AID_ROOT,      AID_SHELL,     0, "system/etc/init.goldfish.rc" },
    { 00550, AID_ROOT,      AID_SHELL,     0, "system/etc/init.goldfish.sh" },
    { 00550, AID_ROOT,      AID_SHELL,     0, "system/etc/init.ril" },
    { 00550, AID_DHCP,      AID_SHELL,     0, "system/etc/dhcpcd/dhcpcd-run-hooks" },
    { 00555, AID_ROOT,      AID_ROOT,      0, "system/etc/ppp/*" },
    { 00555, AID_ROOT,      AID_ROOT,      0, "system/etc/rc.*" },
    { 00644, AID_SYSTEM,    AID_SYSTEM,    0, "data/app/*" },
    { 00644, AID_MEDIA_RW,  AID_MEDIA_RW,  0, "data/media/*" },
    { 00644, AID_SYSTEM,    AID_SYSTEM,    0, "data/app-private/*" },
    { 00644, AID_APP,       AID_APP,       0, "data/data/*" },

    /* the following five files are INTENTIONALLY set-uid, but they
     * are NOT included on user builds. */
    { 04750, AID_ROOT,      AID_SHELL,     0, "system/xbin/su" },
    { 06755, AID_ROOT,      AID_ROOT,      0, "system/xbin/librank" },
    { 06755, AID_ROOT,      AID_ROOT,      0, "system/xbin/procrank" },
    { 06755, AID_ROOT,      AID_ROOT,      0, "system/xbin/procmem" },
    { 04770, AID_ROOT,      AID_RADIO,     0, "system/bin/pppd-ril" },

    /* the following files have enhanced capabilities and ARE included in user builds. */
    { 00750, AID_ROOT,      AID_SHELL,     (1ULL << CAP_SETUID) | (1ULL << CAP_SETGID), "system/bin/run-as" },
    { 00700, AID_SYSTEM,    AID_SHELL,     (1ULL << CAP_BLOCK_SUSPEND), "system/bin/inputflinger" },

    { 00750, AID_ROOT,      AID_ROOT,      0, "system/bin/uncrypt" },
    { 00750, AID_ROOT,      AID_ROOT,      0, "system/bin/install-recovery.sh" },
    { 00755, AID_ROOT,      AID_SHELL,     0, "system/bin/*" },
    { 00755, AID_ROOT,      AID_ROOT,      0, "system/lib/valgrind/*" },
    { 00755, AID_ROOT,      AID_ROOT,      0, "system/lib64/valgrind/*" },
    { 00755, AID_ROOT,      AID_SHELL,     0, "system/xbin/*" },
    { 00755, AID_ROOT,      AID_SHELL,     0, "system/vendor/bin/*" },
    { 00755, AID_ROOT,      AID_SHELL,     0, "vendor/bin/*" },
    { 00750, AID_ROOT,      AID_SHELL,     0, "sbin/*" },
    { 00755, AID_ROOT,      AID_ROOT,      0, "bin/*" },
    { 00750, AID_ROOT,      AID_SHELL,     0, "init*" },
    { 00750, AID_ROOT,      AID_SHELL,     0, "sbin/fs_mgr" },
    { 00640, AID_ROOT,      AID_SHELL,     0, "fstab.*" },
    { 00644, AID_ROOT,      AID_ROOT,      0, 0 },
};

void fs_config(const char *path, int dir,
               unsigned *uid, unsigned *gid, unsigned *mode, uint64_t *capabilities)
{
    const struct fs_path_config *pc;
    int plen;

    if (path[0] == '/') {
        path++;
    }

    pc = dir ? android_dirs : android_files;
    plen = strlen(path);
    for(; pc->prefix; pc++){
        int len = strlen(pc->prefix);
        if (dir) {
            if(plen < len) continue;
            if(!strncmp(pc->prefix, path, len)) break;
            continue;
        }
        /* If name ends in * then allow partial matches. */
        if (pc->prefix[len -1] == '*') {
            if(!strncmp(pc->prefix, path, len - 1)) break;
        } else if (plen == len){
            if(!strncmp(pc->prefix, path, len)) break;
        }
    }
    *uid = pc->uid;
    *gid = pc->gid;
    *mode = (*mode & (~07777)) | pc->mode;
    *capabilities = pc->capabilities;
}