libcutils: convert fs_config.cpp
C++ify fs_config.c
Test: gTest libcutils-test
Bug: 37703469
Change-Id: Id48ae22f203ed923942257575296c69b32345ae6
diff --git a/libcutils/fs_config.cpp b/libcutils/fs_config.cpp
new file mode 100644
index 0000000..a2dd677
--- /dev/null
+++ b/libcutils/fs_config.cpp
@@ -0,0 +1,369 @@
+/*
+ * 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.
+
+#define LOG_TAG "fs_config"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <log/log.h>
+#include <private/android_filesystem_config.h>
+#include <private/fs_config.h>
+#include <utils/Compat.h>
+
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+// My kingdom for <endian.h>
+static inline uint16_t get2LE(const uint8_t* src) {
+ return src[0] | (src[1] << 8);
+}
+
+static inline uint64_t get8LE(const uint8_t* src) {
+ uint32_t low, high;
+
+ low = src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
+ high = src[4] | (src[5] << 8) | (src[6] << 16) | (src[7] << 24);
+ return ((uint64_t)high << 32) | (uint64_t)low;
+}
+
+#define ALIGN(x, alignment) (((x) + ((alignment)-1)) & ~((alignment)-1))
+
+// 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[] = {
+ // clang-format off
+ { 00770, AID_SYSTEM, AID_CACHE, 0, "cache" },
+ { 00500, AID_ROOT, AID_ROOT, 0, "config" },
+ { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app" },
+ { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private" },
+ { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app-ephemeral" },
+ { 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" },
+ { 00770, AID_DHCP, AID_DHCP, 0, "data/misc/dhcp" },
+ { 00771, AID_SHARED_RELRO, AID_SHARED_RELRO, 0, "data/misc/shared_relro" },
+ { 01771, AID_SYSTEM, AID_MISC, 0, "data/misc" },
+ { 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/Music" },
+ { 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media" },
+ { 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest" },
+ { 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest64" },
+ { 00775, AID_ROOT, AID_ROOT, 0, "data/preloads" },
+ { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data" },
+ { 00755, AID_ROOT, AID_SYSTEM, 0, "mnt" },
+ { 00755, AID_ROOT, AID_ROOT, 0, "root" },
+ { 00750, AID_ROOT, AID_SHELL, 0, "sbin" },
+ { 00777, AID_ROOT, AID_ROOT, 0, "sdcard" },
+ { 00751, AID_ROOT, AID_SDCARD_R, 0, "storage" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "system/bin" },
+ { 00755, AID_ROOT, AID_ROOT, 0, "system/etc/ppp" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "system/vendor" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "system/xbin" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "vendor" },
+ { 00755, AID_ROOT, AID_ROOT, 0, 0 },
+ // clang-format on
+};
+
+// 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 char sys_conf_dir[] = "/system/etc/fs_config_dirs";
+static const char sys_conf_file[] = "/system/etc/fs_config_files";
+// No restrictions are placed on the vendor and oem file-system config files,
+// although the developer is advised to restrict the scope to the /vendor or
+// oem/ file-system since the intent is to provide support for customized
+// portions of a separate vendor.img or oem.img. Has to remain open so that
+// customization can also land on /system/vendor, /system/oem or /system/odm.
+// We expect build-time checking or filtering when constructing the associated
+// fs_config_* files (see build/tools/fs_config/fs_config_generate.c)
+static const char ven_conf_dir[] = "/vendor/etc/fs_config_dirs";
+static const char ven_conf_file[] = "/vendor/etc/fs_config_files";
+static const char oem_conf_dir[] = "/oem/etc/fs_config_dirs";
+static const char oem_conf_file[] = "/oem/etc/fs_config_files";
+static const char odm_conf_dir[] = "/odm/etc/fs_config_dirs";
+static const char odm_conf_file[] = "/odm/etc/fs_config_files";
+static const char* conf[][2] = {
+ {sys_conf_file, sys_conf_dir},
+ {ven_conf_file, ven_conf_dir},
+ {oem_conf_file, oem_conf_dir},
+ {odm_conf_file, odm_conf_dir},
+};
+
+static const struct fs_path_config android_files[] = {
+ // clang-format off
+ { 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app/*" },
+ { 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app-ephemeral/*" },
+ { 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private/*" },
+ { 00644, AID_APP, AID_APP, 0, "data/data/*" },
+ { 00644, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/*" },
+ { 00640, AID_ROOT, AID_SHELL, 0, "data/nativetest/tests.txt" },
+ { 00640, AID_ROOT, AID_SHELL, 0, "data/nativetest64/tests.txt" },
+ { 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest/*" },
+ { 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest64/*" },
+ { 00600, AID_ROOT, AID_ROOT, 0, "default.prop" },
+ { 00600, AID_ROOT, AID_ROOT, 0, "odm/build.prop" },
+ { 00600, AID_ROOT, AID_ROOT, 0, "odm/default.prop" },
+ { 00444, AID_ROOT, AID_ROOT, 0, odm_conf_dir + 1 },
+ { 00444, AID_ROOT, AID_ROOT, 0, odm_conf_file + 1 },
+ { 00600, AID_ROOT, AID_ROOT, 0, "system/odm/build.prop" },
+ { 00600, AID_ROOT, AID_ROOT, 0, "system/odm/default.prop" },
+ { 00444, AID_ROOT, AID_ROOT, 0, "system/odm/etc/fs_config_dirs" },
+ { 00444, AID_ROOT, AID_ROOT, 0, "system/odm/etc/fs_config_files" },
+ { 00444, AID_ROOT, AID_ROOT, 0, oem_conf_dir + 1 },
+ { 00444, AID_ROOT, AID_ROOT, 0, oem_conf_file + 1 },
+ { 00444, AID_ROOT, AID_ROOT, 0, "system/oem/etc/fs_config_dirs" },
+ { 00444, AID_ROOT, AID_ROOT, 0, "system/oem/etc/fs_config_files" },
+ { 00750, AID_ROOT, AID_SHELL, 0, "sbin/fs_mgr" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "system/bin/crash_dump32" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "system/bin/crash_dump64" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "system/bin/debuggerd" },
+ { 00750, AID_ROOT, AID_ROOT, 0, "system/bin/install-recovery.sh" },
+ { 00700, AID_ROOT, AID_ROOT, 0, "system/bin/secilc" },
+ { 00750, AID_ROOT, AID_ROOT, 0, "system/bin/uncrypt" },
+ { 00600, AID_ROOT, AID_ROOT, 0, "system/build.prop" },
+ { 00444, AID_ROOT, AID_ROOT, 0, sys_conf_dir + 1 },
+ { 00444, AID_ROOT, AID_ROOT, 0, sys_conf_file + 1 },
+ { 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" },
+ { 00555, AID_ROOT, AID_ROOT, 0, "system/etc/ppp/*" },
+ { 00555, AID_ROOT, AID_ROOT, 0, "system/etc/rc.*" },
+ { 00440, AID_ROOT, AID_ROOT, 0, "system/etc/recovery.img" },
+ { 00600, AID_ROOT, AID_ROOT, 0, "system/vendor/build.prop" },
+ { 00600, AID_ROOT, AID_ROOT, 0, "system/vendor/default.prop" },
+ { 00444, AID_ROOT, AID_ROOT, 0, "system/vendor/etc/fs_config_dirs" },
+ { 00444, AID_ROOT, AID_ROOT, 0, "system/vendor/etc/fs_config_files" },
+ { 00600, AID_ROOT, AID_ROOT, 0, "vendor/build.prop" },
+ { 00600, AID_ROOT, AID_ROOT, 0, "vendor/default.prop" },
+ { 00444, AID_ROOT, AID_ROOT, 0, ven_conf_dir + 1 },
+ { 00444, AID_ROOT, AID_ROOT, 0, ven_conf_file + 1 },
+
+ // the following two files are INTENTIONALLY set-uid, but they
+ // are NOT included on user builds.
+ { 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/procmem" },
+ { 04750, AID_ROOT, AID_SHELL, 0, "system/xbin/su" },
+
+ // the following files have enhanced capabilities and ARE included
+ // in user builds.
+ { 00700, AID_SYSTEM, AID_SHELL, CAP_MASK_LONG(CAP_BLOCK_SUSPEND),
+ "system/bin/inputflinger" },
+ { 00550, AID_LOGD, AID_LOGD, CAP_MASK_LONG(CAP_SYSLOG) |
+ CAP_MASK_LONG(CAP_AUDIT_CONTROL) |
+ CAP_MASK_LONG(CAP_SETGID),
+ "system/bin/logd" },
+ { 00750, AID_ROOT, AID_SHELL, CAP_MASK_LONG(CAP_SETUID) |
+ CAP_MASK_LONG(CAP_SETGID),
+ "system/bin/run-as" },
+
+ // Support FIFO scheduling mode in SurfaceFlinger.
+ { 00755, AID_SYSTEM, AID_GRAPHICS, CAP_MASK_LONG(CAP_SYS_NICE),
+ "system/bin/surfaceflinger" },
+
+ // Support hostapd administering a network interface.
+ { 00755, AID_WIFI, AID_WIFI, CAP_MASK_LONG(CAP_NET_ADMIN) |
+ CAP_MASK_LONG(CAP_NET_RAW),
+ "system/bin/hostapd" },
+
+ // Support Bluetooth legacy hal accessing /sys/class/rfkill
+ // Support RT scheduling in Bluetooth
+ { 00700, AID_BLUETOOTH, AID_BLUETOOTH, CAP_MASK_LONG(CAP_NET_ADMIN) |
+ CAP_MASK_LONG(CAP_SYS_NICE),
+ "system/vendor/bin/hw/android.hardware.bluetooth@1.0-service" },
+ { 00700, AID_BLUETOOTH, AID_BLUETOOTH, CAP_MASK_LONG(CAP_NET_ADMIN) |
+ CAP_MASK_LONG(CAP_SYS_NICE),
+ "vendor/bin/hw/android.hardware.bluetooth@1.0-service" },
+
+ // Support wifi_hal_legacy administering a network interface.
+ { 00755, AID_WIFI, AID_WIFI, CAP_MASK_LONG(CAP_NET_ADMIN) |
+ CAP_MASK_LONG(CAP_NET_RAW),
+ "system/vendor/bin/hw/android.hardware.wifi@1.0-service" },
+ { 00755, AID_WIFI, AID_WIFI, CAP_MASK_LONG(CAP_NET_ADMIN) |
+ CAP_MASK_LONG(CAP_NET_RAW),
+ "vendor/bin/hw/android.hardware.wifi@1.0-service" },
+
+ // A non-privileged zygote that spawns isolated processes for web rendering.
+ { 0750, AID_ROOT, AID_ROOT, CAP_MASK_LONG(CAP_SETUID) |
+ CAP_MASK_LONG(CAP_SETGID) |
+ CAP_MASK_LONG(CAP_SETPCAP),
+ "system/bin/webview_zygote32" },
+ { 0750, AID_ROOT, AID_ROOT, CAP_MASK_LONG(CAP_SETUID) |
+ CAP_MASK_LONG(CAP_SETGID) |
+ CAP_MASK_LONG(CAP_SETPCAP),
+ "system/bin/webview_zygote64" },
+
+ // generic defaults
+ { 00755, AID_ROOT, AID_ROOT, 0, "bin/*" },
+ { 00640, AID_ROOT, AID_SHELL, 0, "fstab.*" },
+ { 00750, AID_ROOT, AID_SHELL, 0, "init*" },
+ { 00750, AID_ROOT, AID_SHELL, 0, "sbin/*" },
+ { 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/vendor/bin/*" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "system/vendor/xbin/*" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "system/xbin/*" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "vendor/bin/*" },
+ { 00755, AID_ROOT, AID_SHELL, 0, "vendor/xbin/*" },
+ { 00644, AID_ROOT, AID_ROOT, 0, 0 },
+ // clang-format on
+};
+
+static size_t strip(const char* path, size_t len, const char suffix[]) {
+ if (len < strlen(suffix)) return len;
+ if (strncmp(path + len - strlen(suffix), suffix, strlen(suffix))) return len;
+ return len - strlen(suffix);
+}
+
+static int fs_config_open(int dir, int which, const char* target_out_path) {
+ int fd = -1;
+
+ if (target_out_path && *target_out_path) {
+ // target_out_path is the path to the directory holding content of
+ // system partition but as we cannot guarantee it ends with '/system'
+ // or with or without a trailing slash, need to strip them carefully.
+ char* name = NULL;
+ size_t len = strlen(target_out_path);
+ len = strip(target_out_path, len, "/");
+ len = strip(target_out_path, len, "/system");
+ if (asprintf(&name, "%.*s%s", (int)len, target_out_path, conf[which][dir]) != -1) {
+ fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY | O_BINARY));
+ free(name);
+ }
+ }
+ if (fd < 0) {
+ fd = TEMP_FAILURE_RETRY(open(conf[which][dir], O_RDONLY | O_BINARY));
+ }
+ return fd;
+}
+
+static bool fs_config_cmp(bool dir, const char* prefix, size_t len, const char* path, size_t plen) {
+ if (dir) {
+ if (plen < len) {
+ return false;
+ }
+ } else {
+ // If name ends in * then allow partial matches.
+ if (prefix[len - 1] == '*') {
+ return !strncmp(prefix, path, len - 1);
+ }
+ if (plen != len) {
+ return false;
+ }
+ }
+ return !strncmp(prefix, path, len);
+}
+
+void fs_config(const char* path, int dir, const char* target_out_path, unsigned* uid, unsigned* gid,
+ unsigned* mode, uint64_t* capabilities) {
+ const struct fs_path_config* pc;
+ size_t which, plen;
+
+ if (path[0] == '/') {
+ path++;
+ }
+
+ plen = strlen(path);
+
+ for (which = 0; which < (sizeof(conf) / sizeof(conf[0])); ++which) {
+ struct fs_path_config_from_file header;
+
+ int fd = fs_config_open(dir, which, target_out_path);
+ if (fd < 0) continue;
+
+ while (TEMP_FAILURE_RETRY(read(fd, &header, sizeof(header))) == sizeof(header)) {
+ char* prefix;
+ uint16_t host_len = get2LE((const uint8_t*)&header.len);
+ ssize_t len, remainder = host_len - sizeof(header);
+ if (remainder <= 0) {
+ ALOGE("%s len is corrupted", conf[which][dir]);
+ break;
+ }
+ prefix = static_cast<char*>(calloc(1, remainder));
+ if (!prefix) {
+ ALOGE("%s out of memory", conf[which][dir]);
+ break;
+ }
+ if (TEMP_FAILURE_RETRY(read(fd, prefix, remainder)) != remainder) {
+ free(prefix);
+ ALOGE("%s prefix is truncated", conf[which][dir]);
+ break;
+ }
+ len = strnlen(prefix, remainder);
+ if (len >= remainder) { // missing a terminating null
+ free(prefix);
+ ALOGE("%s is corrupted", conf[which][dir]);
+ break;
+ }
+ if (fs_config_cmp(dir, prefix, len, path, plen)) {
+ free(prefix);
+ close(fd);
+ *uid = get2LE((const uint8_t*)&(header.uid));
+ *gid = get2LE((const uint8_t*)&(header.gid));
+ *mode = (*mode & (~07777)) | get2LE((const uint8_t*)&(header.mode));
+ *capabilities = get8LE((const uint8_t*)&(header.capabilities));
+ return;
+ }
+ free(prefix);
+ }
+ close(fd);
+ }
+
+ for (pc = dir ? android_dirs : android_files; pc->prefix; pc++) {
+ if (fs_config_cmp(dir, pc->prefix, strlen(pc->prefix), path, plen)) {
+ break;
+ }
+ }
+ *uid = pc->uid;
+ *gid = pc->gid;
+ *mode = (*mode & (~07777)) | pc->mode;
+ *capabilities = pc->capabilities;
+}
+
+ssize_t fs_config_generate(char* buffer, size_t length, const struct fs_path_config* pc) {
+ struct fs_path_config_from_file* p = (struct fs_path_config_from_file*)buffer;
+ size_t len = ALIGN(sizeof(*p) + strlen(pc->prefix) + 1, sizeof(uint64_t));
+
+ if ((length < len) || (len > UINT16_MAX)) {
+ return -ENOSPC;
+ }
+ memset(p, 0, len);
+ uint16_t host_len = len;
+ p->len = get2LE((const uint8_t*)&host_len);
+ p->mode = get2LE((const uint8_t*)&(pc->mode));
+ p->uid = get2LE((const uint8_t*)&(pc->uid));
+ p->gid = get2LE((const uint8_t*)&(pc->gid));
+ p->capabilities = get8LE((const uint8_t*)&(pc->capabilities));
+ strcpy(p->prefix, pc->prefix);
+ return len;
+}