278 lines
10 KiB
C
278 lines
10 KiB
C
/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/* This file is used to define the properties of the filesystem
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** images generated by build tools (mkbootfs and mkyaffs2image) and
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** by the device side of adb.
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*/
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#define LOG_TAG "fs_config"
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <log/log.h>
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#include <private/android_filesystem_config.h>
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#include <utils/Compat.h>
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#ifndef O_BINARY
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#define O_BINARY 0
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#endif
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/* The following structure is stored little endian */
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struct fs_path_config_from_file {
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uint16_t len;
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uint16_t mode;
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uint16_t uid;
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uint16_t gid;
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uint64_t capabilities;
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char prefix[];
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} __attribute__((__aligned__(sizeof(uint64_t))));
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/* My kingdom for <endian.h> */
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static inline uint16_t get2LE(const uint8_t* src)
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{
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return src[0] | (src[1] << 8);
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}
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static inline uint64_t get8LE(const uint8_t* src)
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{
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uint32_t low, high;
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low = src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
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high = src[4] | (src[5] << 8) | (src[6] << 16) | (src[7] << 24);
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return ((uint64_t) high << 32) | (uint64_t) low;
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}
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#define ALIGN(x, alignment) ( ((x) + ((alignment) - 1)) & ~((alignment) - 1) )
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/* Rules for directories.
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** These rules are applied based on "first match", so they
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** should start with the most specific path and work their
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** way up to the root.
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*/
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static const struct fs_path_config android_dirs[] = {
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{ 00770, AID_SYSTEM, AID_CACHE, 0, "cache" },
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{ 00500, AID_ROOT, AID_ROOT, 0, "config" },
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{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app" },
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{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private" },
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{ 00771, AID_ROOT, AID_ROOT, 0, "data/dalvik-cache" },
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{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/data" },
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{ 00771, AID_SHELL, AID_SHELL, 0, "data/local/tmp" },
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{ 00771, AID_SHELL, AID_SHELL, 0, "data/local" },
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{ 01771, AID_SYSTEM, AID_MISC, 0, "data/misc" },
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{ 00770, AID_DHCP, AID_DHCP, 0, "data/misc/dhcp" },
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{ 00771, AID_SHARED_RELRO, AID_SHARED_RELRO, 0, "data/misc/shared_relro" },
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{ 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media" },
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{ 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/Music" },
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{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data" },
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{ 00755, AID_ROOT, AID_SYSTEM, 0, "mnt" },
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{ 00755, AID_ROOT, AID_ROOT, 0, "root" },
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{ 00750, AID_ROOT, AID_SHELL, 0, "sbin" },
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{ 00751, AID_ROOT, AID_SDCARD_R, 0, "storage" },
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{ 00755, AID_ROOT, AID_SHELL, 0, "system/bin" },
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{ 00755, AID_ROOT, AID_SHELL, 0, "system/vendor" },
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{ 00755, AID_ROOT, AID_SHELL, 0, "system/xbin" },
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{ 00755, AID_ROOT, AID_ROOT, 0, "system/etc/ppp" },
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{ 00755, AID_ROOT, AID_SHELL, 0, "vendor" },
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{ 00777, AID_ROOT, AID_ROOT, 0, "sdcard" },
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{ 00755, AID_ROOT, AID_ROOT, 0, 0 },
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};
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/* Rules for files.
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** These rules are applied based on "first match", so they
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** should start with the most specific path and work their
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** way up to the root. Prefixes ending in * denotes wildcard
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** and will allow partial matches.
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*/
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static const char conf_dir[] = "/system/etc/fs_config_dirs";
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static const char conf_file[] = "/system/etc/fs_config_files";
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static const struct fs_path_config android_files[] = {
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{ 00440, AID_ROOT, AID_SHELL, 0, "system/etc/init.goldfish.rc" },
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{ 00550, AID_ROOT, AID_SHELL, 0, "system/etc/init.goldfish.sh" },
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{ 00550, AID_ROOT, AID_SHELL, 0, "system/etc/init.ril" },
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{ 00550, AID_DHCP, AID_SHELL, 0, "system/etc/dhcpcd/dhcpcd-run-hooks" },
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{ 00555, AID_ROOT, AID_ROOT, 0, "system/etc/ppp/*" },
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{ 00555, AID_ROOT, AID_ROOT, 0, "system/etc/rc.*" },
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{ 00444, AID_ROOT, AID_ROOT, 0, conf_dir + 1 },
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{ 00444, AID_ROOT, AID_ROOT, 0, conf_file + 1 },
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{ 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app/*" },
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{ 00644, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/*" },
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{ 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private/*" },
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{ 00644, AID_APP, AID_APP, 0, "data/data/*" },
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/* the following five files are INTENTIONALLY set-uid, but they
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* are NOT included on user builds. */
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{ 04750, AID_ROOT, AID_SHELL, 0, "system/xbin/su" },
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{ 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/librank" },
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{ 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/procrank" },
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{ 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/procmem" },
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{ 04770, AID_ROOT, AID_RADIO, 0, "system/bin/pppd-ril" },
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/* the following files have enhanced capabilities and ARE included in user builds. */
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{ 00750, AID_ROOT, AID_SHELL, (1ULL << CAP_SETUID) | (1ULL << CAP_SETGID), "system/bin/run-as" },
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{ 00700, AID_SYSTEM, AID_SHELL, (1ULL << CAP_BLOCK_SUSPEND), "system/bin/inputflinger" },
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{ 00750, AID_ROOT, AID_ROOT, 0, "system/bin/uncrypt" },
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{ 00750, AID_ROOT, AID_ROOT, 0, "system/bin/install-recovery.sh" },
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{ 00755, AID_ROOT, AID_SHELL, 0, "system/bin/*" },
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{ 00755, AID_ROOT, AID_ROOT, 0, "system/lib/valgrind/*" },
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{ 00755, AID_ROOT, AID_ROOT, 0, "system/lib64/valgrind/*" },
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{ 00755, AID_ROOT, AID_SHELL, 0, "system/xbin/*" },
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{ 00755, AID_ROOT, AID_SHELL, 0, "system/vendor/bin/*" },
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{ 00755, AID_ROOT, AID_SHELL, 0, "vendor/bin/*" },
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{ 00750, AID_ROOT, AID_SHELL, 0, "sbin/*" },
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{ 00755, AID_ROOT, AID_ROOT, 0, "bin/*" },
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{ 00750, AID_ROOT, AID_SHELL, 0, "init*" },
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{ 00750, AID_ROOT, AID_SHELL, 0, "sbin/fs_mgr" },
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{ 00640, AID_ROOT, AID_SHELL, 0, "fstab.*" },
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{ 00644, AID_ROOT, AID_ROOT, 0, 0 },
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};
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static int fs_config_open(int dir)
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{
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int fd = -1;
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const char *out = getenv("OUT");
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if (out && *out) {
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char *name = NULL;
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asprintf(&name, "%s%s", out, dir ? conf_dir : conf_file);
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if (name) {
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fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY | O_BINARY));
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free(name);
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}
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}
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if (fd < 0) {
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fd = TEMP_FAILURE_RETRY(open(dir ? conf_dir : conf_file, O_RDONLY | O_BINARY));
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}
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return fd;
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}
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static bool fs_config_cmp(bool dir, const char *prefix, size_t len,
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const char *path, size_t plen)
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{
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if (dir) {
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if (plen < len) {
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return false;
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}
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} else {
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/* If name ends in * then allow partial matches. */
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if (prefix[len - 1] == '*') {
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return !strncmp(prefix, path, len - 1);
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}
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if (plen != len) {
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return false;
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}
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}
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return !strncmp(prefix, path, len);
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}
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void fs_config(const char *path, int dir,
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unsigned *uid, unsigned *gid, unsigned *mode, uint64_t *capabilities)
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{
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const struct fs_path_config *pc;
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int fd, plen;
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if (path[0] == '/') {
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path++;
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}
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plen = strlen(path);
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fd = fs_config_open(dir);
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if (fd >= 0) {
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struct fs_path_config_from_file header;
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while (TEMP_FAILURE_RETRY(read(fd, &header, sizeof(header))) == sizeof(header)) {
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char *prefix;
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uint16_t host_len = get2LE((const uint8_t *)&header.len);
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ssize_t len, remainder = host_len - sizeof(header);
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if (remainder <= 0) {
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ALOGE("%s len is corrupted", dir ? conf_dir : conf_file);
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break;
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}
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prefix = calloc(1, remainder);
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if (!prefix) {
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ALOGE("%s out of memory", dir ? conf_dir : conf_file);
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break;
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}
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if (TEMP_FAILURE_RETRY(read(fd, prefix, remainder)) != remainder) {
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free(prefix);
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ALOGE("%s prefix is truncated", dir ? conf_dir : conf_file);
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break;
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}
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len = strnlen(prefix, remainder);
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if (len >= remainder) { /* missing a terminating null */
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free(prefix);
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ALOGE("%s is corrupted", dir ? conf_dir : conf_file);
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break;
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}
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if (fs_config_cmp(dir, prefix, len, path, plen)) {
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free(prefix);
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close(fd);
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*uid = get2LE((const uint8_t *)&(header.uid));
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*gid = get2LE((const uint8_t *)&(header.gid));
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*mode = (*mode & (~07777)) | get2LE((const uint8_t *)&(header.mode));
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*capabilities = get8LE((const uint8_t *)&(header.capabilities));
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return;
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}
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free(prefix);
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}
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close(fd);
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}
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pc = dir ? android_dirs : android_files;
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for(; pc->prefix; pc++){
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if (fs_config_cmp(dir, pc->prefix, strlen(pc->prefix), path, plen)) {
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break;
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}
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}
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*uid = pc->uid;
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*gid = pc->gid;
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*mode = (*mode & (~07777)) | pc->mode;
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*capabilities = pc->capabilities;
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}
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ssize_t fs_config_generate(char *buffer, size_t length, const struct fs_path_config *pc)
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{
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struct fs_path_config_from_file *p = (struct fs_path_config_from_file *)buffer;
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size_t len = ALIGN(sizeof(*p) + strlen(pc->prefix) + 1, sizeof(uint64_t));
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if ((length < len) || (len > UINT16_MAX)) {
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return -ENOSPC;
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}
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memset(p, 0, len);
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uint16_t host_len = len;
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p->len = get2LE((const uint8_t *)&host_len);
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p->mode = get2LE((const uint8_t *)&(pc->mode));
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p->uid = get2LE((const uint8_t *)&(pc->uid));
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p->gid = get2LE((const uint8_t *)&(pc->gid));
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p->capabilities = get8LE((const uint8_t *)&(pc->capabilities));
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strcpy(p->prefix, pc->prefix);
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return len;
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}
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