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v811_spc009/system/core/init/property_service.cpp

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/*
* 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.
*/
#include "property_service.h"
#include <android/api-level.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <netinet/in.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/poll.h>
#include <sys/select.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>
#include <wchar.h>
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include <sys/_system_properties.h>
#include <map>
#include <memory>
#include <mutex>
#include <optional>
#include <queue>
#include <string_view>
#include <thread>
#include <vector>
#include <InitProperties.sysprop.h>
#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <property_info_parser/property_info_parser.h>
#include <property_info_serializer/property_info_serializer.h>
#include <selinux/android.h>
#include <selinux/label.h>
#include <selinux/selinux.h>
#include "debug_ramdisk.h"
#include "epoll.h"
#include "init.h"
#include "persistent_properties.h"
#include "property_type.h"
#include "proto_utils.h"
#include "second_stage_resources.h"
#include "selinux.h"
#include "subcontext.h"
#include "system/core/init/property_service.pb.h"
#include "util.h"
using namespace std::literals;
using android::base::GetProperty;
using android::base::ParseInt;
using android::base::ReadFileToString;
using android::base::Split;
using android::base::StartsWith;
using android::base::StringPrintf;
using android::base::Timer;
using android::base::Trim;
using android::base::unique_fd;
using android::base::WriteStringToFile;
using android::properties::BuildTrie;
using android::properties::ParsePropertyInfoFile;
using android::properties::PropertyInfoAreaFile;
using android::properties::PropertyInfoEntry;
using android::sysprop::InitProperties::is_userspace_reboot_supported;
namespace android {
namespace init {
constexpr auto FINGERPRINT_PROP = "ro.build.fingerprint";
constexpr auto LEGACY_FINGERPRINT_PROP = "ro.build.legacy.fingerprint";
constexpr auto ID_PROP = "ro.build.id";
constexpr auto LEGACY_ID_PROP = "ro.build.legacy.id";
constexpr auto VBMETA_DIGEST_PROP = "ro.boot.vbmeta.digest";
constexpr auto DIGEST_SIZE_USED = 8;
static bool persistent_properties_loaded = false;
static int property_set_fd = -1;
static int from_init_socket = -1;
static int init_socket = -1;
static bool accept_messages = false;
static std::mutex accept_messages_lock;
static std::thread property_service_thread;
static PropertyInfoAreaFile property_info_area;
struct PropertyAuditData {
const ucred* cr;
const char* name;
};
static int PropertyAuditCallback(void* data, security_class_t /*cls*/, char* buf, size_t len) {
auto* d = reinterpret_cast<PropertyAuditData*>(data);
if (!d || !d->name || !d->cr) {
LOG(ERROR) << "AuditCallback invoked with null data arguments!";
return 0;
}
snprintf(buf, len, "property=%s pid=%d uid=%d gid=%d", d->name, d->cr->pid, d->cr->uid,
d->cr->gid);
return 0;
}
void StartSendingMessages() {
auto lock = std::lock_guard{accept_messages_lock};
accept_messages = true;
}
void StopSendingMessages() {
auto lock = std::lock_guard{accept_messages_lock};
accept_messages = false;
}
bool CanReadProperty(const std::string& source_context, const std::string& name) {
const char* target_context = nullptr;
property_info_area->GetPropertyInfo(name.c_str(), &target_context, nullptr);
PropertyAuditData audit_data;
audit_data.name = name.c_str();
ucred cr = {.pid = 0, .uid = 0, .gid = 0};
audit_data.cr = &cr;
return selinux_check_access(source_context.c_str(), target_context, "file", "read",
&audit_data) == 0;
}
static bool CheckMacPerms(const std::string& name, const char* target_context,
const char* source_context, const ucred& cr) {
if (!target_context || !source_context) {
return false;
}
PropertyAuditData audit_data;
audit_data.name = name.c_str();
audit_data.cr = &cr;
bool has_access = (selinux_check_access(source_context, target_context, "property_service",
"set", &audit_data) == 0);
return has_access;
}
static uint32_t PropertySet(const std::string& name, const std::string& value, std::string* error) {
size_t valuelen = value.size();
if (!IsLegalPropertyName(name)) {
*error = "Illegal property name";
return PROP_ERROR_INVALID_NAME;
}
if (auto result = IsLegalPropertyValue(name, value); !result.ok()) {
*error = result.error().message();
return PROP_ERROR_INVALID_VALUE;
}
prop_info* pi = (prop_info*) __system_property_find(name.c_str());
if (pi != nullptr) {
// ro.* properties are actually "write-once".
if (StartsWith(name, "ro.")) {
*error = "Read-only property was already set";
return PROP_ERROR_READ_ONLY_PROPERTY;
}
__system_property_update(pi, value.c_str(), valuelen);
} else {
int rc = __system_property_add(name.c_str(), name.size(), value.c_str(), valuelen);
if (rc < 0) {
*error = "__system_property_add failed";
return PROP_ERROR_SET_FAILED;
}
}
// Don't write properties to disk until after we have read all default
// properties to prevent them from being overwritten by default values.
if (persistent_properties_loaded && StartsWith(name, "persist.")) {
WritePersistentProperty(name, value);
}
// If init hasn't started its main loop, then it won't be handling property changed messages
// anyway, so there's no need to try to send them.
auto lock = std::lock_guard{accept_messages_lock};
if (accept_messages) {
PropertyChanged(name, value);
}
return PROP_SUCCESS;
}
class AsyncRestorecon {
public:
void TriggerRestorecon(const std::string& path) {
auto guard = std::lock_guard{mutex_};
paths_.emplace(path);
if (!thread_started_) {
thread_started_ = true;
std::thread{&AsyncRestorecon::ThreadFunction, this}.detach();
}
}
private:
void ThreadFunction() {
auto lock = std::unique_lock{mutex_};
while (!paths_.empty()) {
auto path = paths_.front();
paths_.pop();
lock.unlock();
if (selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE) != 0) {
LOG(ERROR) << "Asynchronous restorecon of '" << path << "' failed'";
}
android::base::SetProperty(kRestoreconProperty, path);
lock.lock();
}
thread_started_ = false;
}
std::mutex mutex_;
std::queue<std::string> paths_;
bool thread_started_ = false;
};
class SocketConnection {
public:
SocketConnection(int socket, const ucred& cred) : socket_(socket), cred_(cred) {}
bool RecvUint32(uint32_t* value, uint32_t* timeout_ms) {
return RecvFully(value, sizeof(*value), timeout_ms);
}
bool RecvChars(char* chars, size_t size, uint32_t* timeout_ms) {
return RecvFully(chars, size, timeout_ms);
}
bool RecvString(std::string* value, uint32_t* timeout_ms) {
uint32_t len = 0;
if (!RecvUint32(&len, timeout_ms)) {
return false;
}
if (len == 0) {
*value = "";
return true;
}
// http://b/35166374: don't allow init to make arbitrarily large allocations.
if (len > 0xffff) {
LOG(ERROR) << "sys_prop: RecvString asked to read huge string: " << len;
errno = ENOMEM;
return false;
}
std::vector<char> chars(len);
if (!RecvChars(&chars[0], len, timeout_ms)) {
return false;
}
*value = std::string(&chars[0], len);
return true;
}
bool SendUint32(uint32_t value) {
if (!socket_.ok()) {
return true;
}
int result = TEMP_FAILURE_RETRY(send(socket_, &value, sizeof(value), 0));
return result == sizeof(value);
}
bool GetSourceContext(std::string* source_context) const {
char* c_source_context = nullptr;
if (getpeercon(socket_, &c_source_context) != 0) {
return false;
}
*source_context = c_source_context;
freecon(c_source_context);
return true;
}
[[nodiscard]] int Release() { return socket_.release(); }
const ucred& cred() { return cred_; }
private:
bool PollIn(uint32_t* timeout_ms) {
struct pollfd ufds[1];
ufds[0].fd = socket_;
ufds[0].events = POLLIN;
ufds[0].revents = 0;
while (*timeout_ms > 0) {
auto start_time = std::chrono::steady_clock::now();
int nr = poll(ufds, 1, *timeout_ms);
auto now = std::chrono::steady_clock::now();
auto time_elapsed =
std::chrono::duration_cast<std::chrono::milliseconds>(now - start_time);
uint64_t millis = time_elapsed.count();
*timeout_ms = (millis > *timeout_ms) ? 0 : *timeout_ms - millis;
if (nr > 0) {
return true;
}
if (nr == 0) {
// Timeout
break;
}
if (nr < 0 && errno != EINTR) {
PLOG(ERROR) << "sys_prop: error waiting for uid " << cred_.uid
<< " to send property message";
return false;
} else { // errno == EINTR
// Timer rounds milliseconds down in case of EINTR we want it to be rounded up
// to avoid slowing init down by causing EINTR with under millisecond timeout.
if (*timeout_ms > 0) {
--(*timeout_ms);
}
}
}
LOG(ERROR) << "sys_prop: timeout waiting for uid " << cred_.uid
<< " to send property message.";
return false;
}
bool RecvFully(void* data_ptr, size_t size, uint32_t* timeout_ms) {
size_t bytes_left = size;
char* data = static_cast<char*>(data_ptr);
while (*timeout_ms > 0 && bytes_left > 0) {
if (!PollIn(timeout_ms)) {
return false;
}
int result = TEMP_FAILURE_RETRY(recv(socket_, data, bytes_left, MSG_DONTWAIT));
if (result <= 0) {
PLOG(ERROR) << "sys_prop: recv error";
return false;
}
bytes_left -= result;
data += result;
}
if (bytes_left != 0) {
LOG(ERROR) << "sys_prop: recv data is not properly obtained.";
}
return bytes_left == 0;
}
unique_fd socket_;
ucred cred_;
DISALLOW_IMPLICIT_CONSTRUCTORS(SocketConnection);
};
static uint32_t SendControlMessage(const std::string& msg, const std::string& name, pid_t pid,
SocketConnection* socket, std::string* error) {
auto lock = std::lock_guard{accept_messages_lock};
if (!accept_messages) {
*error = "Received control message after shutdown, ignoring";
return PROP_ERROR_HANDLE_CONTROL_MESSAGE;
}
// We must release the fd before sending it to init, otherwise there will be a race with init.
// If init calls close() before Release(), then fdsan will see the wrong tag and abort().
int fd = -1;
if (socket != nullptr && SelinuxGetVendorAndroidVersion() > __ANDROID_API_Q__) {
fd = socket->Release();
}
bool queue_success = QueueControlMessage(msg, name, pid, fd);
if (!queue_success && fd != -1) {
uint32_t response = PROP_ERROR_HANDLE_CONTROL_MESSAGE;
TEMP_FAILURE_RETRY(send(fd, &response, sizeof(response), 0));
close(fd);
}
return PROP_SUCCESS;
}
bool CheckControlPropertyPerms(const std::string& name, const std::string& value,
const std::string& source_context, const ucred& cr) {
// We check the legacy method first but these properties are dontaudit, so we only log an audit
// if the newer method fails as well. We only do this with the legacy ctl. properties.
if (name == "ctl.start" || name == "ctl.stop" || name == "ctl.restart") {
// The legacy permissions model is that ctl. properties have their name ctl.<action> and
// their value is the name of the service to apply that action to. Permissions for these
// actions are based on the service, so we must create a fake name of ctl.<service> to
// check permissions.
auto control_string_legacy = "ctl." + value;
const char* target_context_legacy = nullptr;
const char* type_legacy = nullptr;
property_info_area->GetPropertyInfo(control_string_legacy.c_str(), &target_context_legacy,
&type_legacy);
if (CheckMacPerms(control_string_legacy, target_context_legacy, source_context.c_str(), cr)) {
return true;
}
}
auto control_string_full = name + "$" + value;
const char* target_context_full = nullptr;
const char* type_full = nullptr;
property_info_area->GetPropertyInfo(control_string_full.c_str(), &target_context_full,
&type_full);
return CheckMacPerms(control_string_full, target_context_full, source_context.c_str(), cr);
}
// This returns one of the enum of PROP_SUCCESS or PROP_ERROR*.
uint32_t CheckPermissions(const std::string& name, const std::string& value,
const std::string& source_context, const ucred& cr, std::string* error) {
if (!IsLegalPropertyName(name)) {
*error = "Illegal property name";
return PROP_ERROR_INVALID_NAME;
}
if (StartsWith(name, "ctl.")) {
if (!CheckControlPropertyPerms(name, value, source_context, cr)) {
*error = StringPrintf("Invalid permissions to perform '%s' on '%s'", name.c_str() + 4,
value.c_str());
return PROP_ERROR_HANDLE_CONTROL_MESSAGE;
}
return PROP_SUCCESS;
}
const char* target_context = nullptr;
const char* type = nullptr;
property_info_area->GetPropertyInfo(name.c_str(), &target_context, &type);
if (!CheckMacPerms(name, target_context, source_context.c_str(), cr)) {
*error = "SELinux permission check failed";
return PROP_ERROR_PERMISSION_DENIED;
}
if (!CheckType(type, value)) {
*error = StringPrintf("Property type check failed, value doesn't match expected type '%s'",
(type ?: "(null)"));
return PROP_ERROR_INVALID_VALUE;
}
return PROP_SUCCESS;
}
// This returns one of the enum of PROP_SUCCESS or PROP_ERROR*.
uint32_t HandlePropertySet(const std::string& name, const std::string& value,
const std::string& source_context, const ucred& cr,
SocketConnection* socket, std::string* error) {
if (auto ret = CheckPermissions(name, value, source_context, cr, error); ret != PROP_SUCCESS) {
return ret;
}
if (StartsWith(name, "ctl.")) {
return SendControlMessage(name.c_str() + 4, value, cr.pid, socket, error);
}
// sys.powerctl is a special property that is used to make the device reboot. We want to log
// any process that sets this property to be able to accurately blame the cause of a shutdown.
if (name == "sys.powerctl") {
std::string cmdline_path = StringPrintf("proc/%d/cmdline", cr.pid);
std::string process_cmdline;
std::string process_log_string;
if (ReadFileToString(cmdline_path, &process_cmdline)) {
// Since cmdline is null deliminated, .c_str() conveniently gives us just the process
// path.
process_log_string = StringPrintf(" (%s)", process_cmdline.c_str());
}
LOG(INFO) << "Received sys.powerctl='" << value << "' from pid: " << cr.pid
<< process_log_string;
if (!value.empty()) {
DebugRebootLogging();
}
if (value == "reboot,userspace" && !is_userspace_reboot_supported().value_or(false)) {
*error = "Userspace reboot is not supported by this device";
return PROP_ERROR_INVALID_VALUE;
}
}
// If a process other than init is writing a non-empty value, it means that process is
// requesting that init performs a restorecon operation on the path specified by 'value'.
// We use a thread to do this restorecon operation to prevent holding up init, as it may take
// a long time to complete.
if (name == kRestoreconProperty && cr.pid != 1 && !value.empty()) {
static AsyncRestorecon async_restorecon;
async_restorecon.TriggerRestorecon(value);
return PROP_SUCCESS;
}
return PropertySet(name, value, error);
}
static void handle_property_set_fd() {
static constexpr uint32_t kDefaultSocketTimeout = 2000; /* ms */
int s = accept4(property_set_fd, nullptr, nullptr, SOCK_CLOEXEC);
if (s == -1) {
return;
}
ucred cr;
socklen_t cr_size = sizeof(cr);
if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) {
close(s);
PLOG(ERROR) << "sys_prop: unable to get SO_PEERCRED";
return;
}
SocketConnection socket(s, cr);
uint32_t timeout_ms = kDefaultSocketTimeout;
uint32_t cmd = 0;
if (!socket.RecvUint32(&cmd, &timeout_ms)) {
PLOG(ERROR) << "sys_prop: error while reading command from the socket";
socket.SendUint32(PROP_ERROR_READ_CMD);
return;
}
switch (cmd) {
case PROP_MSG_SETPROP: {
char prop_name[PROP_NAME_MAX];
char prop_value[PROP_VALUE_MAX];
if (!socket.RecvChars(prop_name, PROP_NAME_MAX, &timeout_ms) ||
!socket.RecvChars(prop_value, PROP_VALUE_MAX, &timeout_ms)) {
PLOG(ERROR) << "sys_prop(PROP_MSG_SETPROP): error while reading name/value from the socket";
return;
}
prop_name[PROP_NAME_MAX-1] = 0;
prop_value[PROP_VALUE_MAX-1] = 0;
std::string source_context;
if (!socket.GetSourceContext(&source_context)) {
PLOG(ERROR) << "Unable to set property '" << prop_name << "': getpeercon() failed";
return;
}
const auto& cr = socket.cred();
std::string error;
uint32_t result =
HandlePropertySet(prop_name, prop_value, source_context, cr, nullptr, &error);
if (result != PROP_SUCCESS) {
LOG(ERROR) << "Unable to set property '" << prop_name << "' from uid:" << cr.uid
<< " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
}
break;
}
case PROP_MSG_SETPROP2: {
std::string name;
std::string value;
if (!socket.RecvString(&name, &timeout_ms) ||
!socket.RecvString(&value, &timeout_ms)) {
PLOG(ERROR) << "sys_prop(PROP_MSG_SETPROP2): error while reading name/value from the socket";
socket.SendUint32(PROP_ERROR_READ_DATA);
return;
}
std::string source_context;
if (!socket.GetSourceContext(&source_context)) {
PLOG(ERROR) << "Unable to set property '" << name << "': getpeercon() failed";
socket.SendUint32(PROP_ERROR_PERMISSION_DENIED);
return;
}
const auto& cr = socket.cred();
std::string error;
uint32_t result = HandlePropertySet(name, value, source_context, cr, &socket, &error);
if (result != PROP_SUCCESS) {
LOG(ERROR) << "Unable to set property '" << name << "' from uid:" << cr.uid
<< " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
}
socket.SendUint32(result);
break;
}
default:
LOG(ERROR) << "sys_prop: invalid command " << cmd;
socket.SendUint32(PROP_ERROR_INVALID_CMD);
break;
}
}
uint32_t InitPropertySet(const std::string& name, const std::string& value) {
uint32_t result = 0;
ucred cr = {.pid = 1, .uid = 0, .gid = 0};
std::string error;
result = HandlePropertySet(name, value, kInitContext, cr, nullptr, &error);
if (result != PROP_SUCCESS) {
LOG(ERROR) << "Init cannot set '" << name << "' to '" << value << "': " << error;
}
return result;
}
static bool load_properties_from_file(const char*, const char*,
std::map<std::string, std::string>*);
/*
* Filter is used to decide which properties to load: NULL loads all keys,
* "ro.foo.*" is a prefix match, and "ro.foo.bar" is an exact match.
*/
static void LoadProperties(char* data, const char* filter, const char* filename,
std::map<std::string, std::string>* properties) {
char *key, *value, *eol, *sol, *tmp, *fn;
size_t flen = 0;
static constexpr const char* const kVendorPathPrefixes[4] = {
"/vendor",
"/odm",
"/vendor_dlkm",
"/odm_dlkm",
};
const char* context = kInitContext;
if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_P__) {
for (const auto& vendor_path_prefix : kVendorPathPrefixes) {
if (StartsWith(filename, vendor_path_prefix)) {
context = kVendorContext;
}
}
}
if (filter) {
flen = strlen(filter);
}
sol = data;
while ((eol = strchr(sol, '\n'))) {
key = sol;
*eol++ = 0;
sol = eol;
while (isspace(*key)) key++;
if (*key == '#') continue;
tmp = eol - 2;
while ((tmp > key) && isspace(*tmp)) *tmp-- = 0;
if (!strncmp(key, "import ", 7) && flen == 0) {
fn = key + 7;
while (isspace(*fn)) fn++;
key = strchr(fn, ' ');
if (key) {
*key++ = 0;
while (isspace(*key)) key++;
}
std::string raw_filename(fn);
auto expanded_filename = ExpandProps(raw_filename);
if (!expanded_filename.ok()) {
LOG(ERROR) << "Could not expand filename ': " << expanded_filename.error();
continue;
}
load_properties_from_file(expanded_filename->c_str(), key, properties);
} else {
value = strchr(key, '=');
if (!value) continue;
*value++ = 0;
tmp = value - 2;
while ((tmp > key) && isspace(*tmp)) *tmp-- = 0;
while (isspace(*value)) value++;
if (flen > 0) {
if (filter[flen - 1] == '*') {
if (strncmp(key, filter, flen - 1) != 0) continue;
} else {
if (strcmp(key, filter) != 0) continue;
}
}
if (StartsWith(key, "ctl.") || key == "sys.powerctl"s ||
std::string{key} == kRestoreconProperty) {
LOG(ERROR) << "Ignoring disallowed property '" << key
<< "' with special meaning in prop file '" << filename << "'";
continue;
}
ucred cr = {.pid = 1, .uid = 0, .gid = 0};
std::string error;
if (CheckPermissions(key, value, context, cr, &error) == PROP_SUCCESS) {
auto it = properties->find(key);
if (it == properties->end()) {
(*properties)[key] = value;
} else if (it->second != value) {
LOG(WARNING) << "Overriding previous property '" << key << "':'" << it->second
<< "' with new value '" << value << "'";
it->second = value;
}
} else {
LOG(ERROR) << "Do not have permissions to set '" << key << "' to '" << value
<< "' in property file '" << filename << "': " << error;
}
}
}
}
// Filter is used to decide which properties to load: NULL loads all keys,
// "ro.foo.*" is a prefix match, and "ro.foo.bar" is an exact match.
static bool load_properties_from_file(const char* filename, const char* filter,
std::map<std::string, std::string>* properties) {
Timer t;
auto file_contents = ReadFile(filename);
if (!file_contents.ok()) {
PLOG(WARNING) << "Couldn't load property file '" << filename
<< "': " << file_contents.error();
return false;
}
file_contents->push_back('\n');
LoadProperties(file_contents->data(), filter, filename, properties);
LOG(VERBOSE) << "(Loading properties from " << filename << " took " << t << ".)";
return true;
}
static void LoadPropertiesFromSecondStageRes(std::map<std::string, std::string>* properties) {
std::string prop = GetRamdiskPropForSecondStage();
if (access(prop.c_str(), R_OK) != 0) {
CHECK(errno == ENOENT) << "Cannot access " << prop << ": " << strerror(errno);
return;
}
load_properties_from_file(prop.c_str(), nullptr, properties);
}
// persist.sys.usb.config values can't be combined on build-time when property
// files are split into each partition.
// So we need to apply the same rule of build/make/tools/post_process_props.py
// on runtime.
static void update_sys_usb_config() {
bool is_debuggable = android::base::GetBoolProperty("ro.debuggable", false);
std::string config = android::base::GetProperty("persist.sys.usb.config", "");
// b/150130503, add (config == "none") condition here to prevent appending
// ",adb" if "none" is explicitly defined in default prop.
if (config.empty() || config == "none") {
InitPropertySet("persist.sys.usb.config", is_debuggable ? "adb" : "none");
} else if (is_debuggable && config.find("adb") == std::string::npos &&
config.length() + 4 < PROP_VALUE_MAX) {
config.append(",adb");
InitPropertySet("persist.sys.usb.config", config);
}
}
static void load_override_properties() {
if (ALLOW_LOCAL_PROP_OVERRIDE) {
std::map<std::string, std::string> properties;
load_properties_from_file("/data/local.prop", nullptr, &properties);
for (const auto& [name, value] : properties) {
std::string error;
if (PropertySet(name, value, &error) != PROP_SUCCESS) {
LOG(ERROR) << "Could not set '" << name << "' to '" << value
<< "' in /data/local.prop: " << error;
}
}
}
}
// If the ro.product.[brand|device|manufacturer|model|name] properties have not been explicitly
// set, derive them from ro.product.${partition}.* properties
static void property_initialize_ro_product_props() {
const char* RO_PRODUCT_PROPS_PREFIX = "ro.product.";
const char* RO_PRODUCT_PROPS[] = {
"brand", "device", "manufacturer", "model", "name",
};
const char* RO_PRODUCT_PROPS_ALLOWED_SOURCES[] = {
"odm", "product", "system_ext", "system", "vendor",
};
const char* RO_PRODUCT_PROPS_DEFAULT_SOURCE_ORDER = "product,odm,vendor,system_ext,system";
const std::string EMPTY = "";
std::string ro_product_props_source_order =
GetProperty("ro.product.property_source_order", EMPTY);
if (!ro_product_props_source_order.empty()) {
// Verify that all specified sources are valid
for (const auto& source : Split(ro_product_props_source_order, ",")) {
// Verify that the specified source is valid
bool is_allowed_source = false;
for (const auto& allowed_source : RO_PRODUCT_PROPS_ALLOWED_SOURCES) {
if (source == allowed_source) {
is_allowed_source = true;
break;
}
}
if (!is_allowed_source) {
LOG(ERROR) << "Found unexpected source in ro.product.property_source_order; "
"using the default property source order";
ro_product_props_source_order = RO_PRODUCT_PROPS_DEFAULT_SOURCE_ORDER;
break;
}
}
} else {
ro_product_props_source_order = RO_PRODUCT_PROPS_DEFAULT_SOURCE_ORDER;
}
for (const auto& ro_product_prop : RO_PRODUCT_PROPS) {
std::string base_prop(RO_PRODUCT_PROPS_PREFIX);
base_prop += ro_product_prop;
std::string base_prop_val = GetProperty(base_prop, EMPTY);
if (!base_prop_val.empty()) {
continue;
}
for (const auto& source : Split(ro_product_props_source_order, ",")) {
std::string target_prop(RO_PRODUCT_PROPS_PREFIX);
target_prop += source;
target_prop += '.';
target_prop += ro_product_prop;
std::string target_prop_val = GetProperty(target_prop, EMPTY);
if (!target_prop_val.empty()) {
LOG(INFO) << "Setting product property " << base_prop << " to '" << target_prop_val
<< "' (from " << target_prop << ")";
std::string error;
uint32_t res = PropertySet(base_prop, target_prop_val, &error);
if (res != PROP_SUCCESS) {
LOG(ERROR) << "Error setting product property " << base_prop << ": err=" << res
<< " (" << error << ")";
}
break;
}
}
}
}
static void property_initialize_build_id() {
std::string build_id = GetProperty(ID_PROP, "");
if (!build_id.empty()) {
return;
}
std::string legacy_build_id = GetProperty(LEGACY_ID_PROP, "");
std::string vbmeta_digest = GetProperty(VBMETA_DIGEST_PROP, "");
if (vbmeta_digest.size() < DIGEST_SIZE_USED) {
LOG(ERROR) << "vbmeta digest size too small " << vbmeta_digest;
// Still try to set the id field in the unexpected case.
build_id = legacy_build_id;
} else {
// Derive the ro.build.id by appending the vbmeta digest to the base value.
build_id = legacy_build_id + "." + vbmeta_digest.substr(0, DIGEST_SIZE_USED);
}
std::string error;
auto res = PropertySet(ID_PROP, build_id, &error);
if (res != PROP_SUCCESS) {
LOG(ERROR) << "Failed to set " << ID_PROP << " to " << build_id;
}
}
static std::string ConstructBuildFingerprint(bool legacy) {
const std::string UNKNOWN = "unknown";
std::string build_fingerprint = GetProperty("ro.product.brand", UNKNOWN);
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.product.name", UNKNOWN);
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.product.device", UNKNOWN);
build_fingerprint += ':';
build_fingerprint += GetProperty("ro.build.version.release_or_codename", UNKNOWN);
build_fingerprint += '/';
std::string build_id =
legacy ? GetProperty(LEGACY_ID_PROP, UNKNOWN) : GetProperty(ID_PROP, UNKNOWN);
build_fingerprint += build_id;
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.build.version.incremental", UNKNOWN);
build_fingerprint += ':';
build_fingerprint += GetProperty("ro.build.type", UNKNOWN);
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.build.tags", UNKNOWN);
return build_fingerprint;
}
// Derive the legacy build fingerprint if we overwrite the build id at runtime.
static void property_derive_legacy_build_fingerprint() {
std::string legacy_build_fingerprint = GetProperty(LEGACY_FINGERPRINT_PROP, "");
if (!legacy_build_fingerprint.empty()) {
return;
}
// The device doesn't have a legacy build id, skipping the legacy fingerprint.
std::string legacy_build_id = GetProperty(LEGACY_ID_PROP, "");
if (legacy_build_id.empty()) {
return;
}
legacy_build_fingerprint = ConstructBuildFingerprint(true /* legacy fingerprint */);
LOG(INFO) << "Setting property '" << LEGACY_FINGERPRINT_PROP << "' to '"
<< legacy_build_fingerprint << "'";
std::string error;
uint32_t res = PropertySet(LEGACY_FINGERPRINT_PROP, legacy_build_fingerprint, &error);
if (res != PROP_SUCCESS) {
LOG(ERROR) << "Error setting property '" << LEGACY_FINGERPRINT_PROP << "': err=" << res
<< " (" << error << ")";
}
}
// If the ro.build.fingerprint property has not been set, derive it from constituent pieces
static void property_derive_build_fingerprint() {
std::string build_fingerprint = GetProperty("ro.build.fingerprint", "");
if (!build_fingerprint.empty()) {
return;
}
build_fingerprint = ConstructBuildFingerprint(false /* legacy fingerprint */);
LOG(INFO) << "Setting property '" << FINGERPRINT_PROP << "' to '" << build_fingerprint << "'";
std::string error;
uint32_t res = PropertySet(FINGERPRINT_PROP, build_fingerprint, &error);
if (res != PROP_SUCCESS) {
LOG(ERROR) << "Error setting property '" << FINGERPRINT_PROP << "': err=" << res << " ("
<< error << ")";
}
}
// If the ro.product.cpu.abilist* properties have not been explicitly
// set, derive them from ro.${partition}.product.cpu.abilist* properties.
static void property_initialize_ro_cpu_abilist() {
// From high to low priority.
const char* kAbilistSources[] = {
"product",
"odm",
"vendor",
"system",
};
const std::string EMPTY = "";
const char* kAbilistProp = "ro.product.cpu.abilist";
const char* kAbilist32Prop = "ro.product.cpu.abilist32";
const char* kAbilist64Prop = "ro.product.cpu.abilist64";
// If the properties are defined explicitly, just use them.
if (GetProperty(kAbilistProp, EMPTY) != EMPTY) {
return;
}
// Find the first source defining these properties by order.
std::string abilist32_prop_val;
std::string abilist64_prop_val;
for (const auto& source : kAbilistSources) {
const auto abilist32_prop = std::string("ro.") + source + ".product.cpu.abilist32";
const auto abilist64_prop = std::string("ro.") + source + ".product.cpu.abilist64";
abilist32_prop_val = GetProperty(abilist32_prop, EMPTY);
abilist64_prop_val = GetProperty(abilist64_prop, EMPTY);
// The properties could be empty on 32-bit-only or 64-bit-only devices,
// but we cannot identify a property is empty or undefined by GetProperty().
// So, we assume both of these 2 properties are empty as undefined.
if (abilist32_prop_val != EMPTY || abilist64_prop_val != EMPTY) {
break;
}
}
// Merge ABI lists for ro.product.cpu.abilist
auto abilist_prop_val = abilist64_prop_val;
if (abilist32_prop_val != EMPTY) {
if (abilist_prop_val != EMPTY) {
abilist_prop_val += ",";
}
abilist_prop_val += abilist32_prop_val;
}
// Set these properties
const std::pair<const char*, const std::string&> set_prop_list[] = {
{kAbilistProp, abilist_prop_val},
{kAbilist32Prop, abilist32_prop_val},
{kAbilist64Prop, abilist64_prop_val},
};
for (const auto& [prop, prop_val] : set_prop_list) {
LOG(INFO) << "Setting property '" << prop << "' to '" << prop_val << "'";
std::string error;
uint32_t res = PropertySet(prop, prop_val, &error);
if (res != PROP_SUCCESS) {
LOG(ERROR) << "Error setting property '" << prop << "': err=" << res << " (" << error
<< ")";
}
}
}
void PropertyLoadBootDefaults() {
// We read the properties and their values into a map, in order to always allow properties
// loaded in the later property files to override the properties in loaded in the earlier
// property files, regardless of if they are "ro." properties or not.
std::map<std::string, std::string> properties;
if (IsRecoveryMode()) {
load_properties_from_file("/prop.default", nullptr, &properties);
}
// /<part>/etc/build.prop is the canonical location of the build-time properties since S.
// Falling back to /<part>/defalt.prop and /<part>/build.prop only when legacy path has to
// be supported, which is controlled by the support_legacy_path_until argument.
const auto load_properties_from_partition = [&properties](const std::string& partition,
int support_legacy_path_until) {
auto path = "/" + partition + "/etc/build.prop";
if (load_properties_from_file(path.c_str(), nullptr, &properties)) {
return;
}
// To read ro.<partition>.build.version.sdk, temporarily load the legacy paths into a
// separate map. Then by comparing its value with legacy_version, we know that if the
// partition is old enough so that we need to respect the legacy paths.
std::map<std::string, std::string> temp;
auto legacy_path1 = "/" + partition + "/default.prop";
auto legacy_path2 = "/" + partition + "/build.prop";
load_properties_from_file(legacy_path1.c_str(), nullptr, &temp);
load_properties_from_file(legacy_path2.c_str(), nullptr, &temp);
bool support_legacy_path = false;
auto version_prop_name = "ro." + partition + ".build.version.sdk";
auto it = temp.find(version_prop_name);
if (it == temp.end()) {
// This is embarassing. Without the prop, we can't determine how old the partition is.
// Let's be conservative by assuming it is very very old.
support_legacy_path = true;
} else if (int value;
ParseInt(it->second.c_str(), &value) && value <= support_legacy_path_until) {
support_legacy_path = true;
}
if (support_legacy_path) {
// We don't update temp into properties directly as it might skip any (future) logic
// for resolving duplicates implemented in load_properties_from_file. Instead, read
// the files again into the properties map.
load_properties_from_file(legacy_path1.c_str(), nullptr, &properties);
load_properties_from_file(legacy_path2.c_str(), nullptr, &properties);
} else {
LOG(FATAL) << legacy_path1 << " and " << legacy_path2 << " were not loaded "
<< "because " << version_prop_name << "(" << it->second << ") is newer "
<< "than " << support_legacy_path_until;
}
};
// Order matters here. The more the partition is specific to a product, the higher its
// precedence is.
LoadPropertiesFromSecondStageRes(&properties);
load_properties_from_file("/system/build.prop", nullptr, &properties);
load_properties_from_partition("system_ext", /* support_legacy_path_until */ 30);
// TODO(b/117892318): uncomment the following condition when vendor.imgs for aosp_* targets are
// all updated.
// if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_R__) {
load_properties_from_file("/vendor/default.prop", nullptr, &properties);
// }
load_properties_from_file("/vendor/build.prop", nullptr, &properties);
load_properties_from_file("/vendor_dlkm/etc/build.prop", nullptr, &properties);
load_properties_from_file("/odm_dlkm/etc/build.prop", nullptr, &properties);
load_properties_from_partition("odm", /* support_legacy_path_until */ 28);
load_properties_from_partition("product", /* support_legacy_path_until */ 30);
if (access(kDebugRamdiskProp, R_OK) == 0) {
LOG(INFO) << "Loading " << kDebugRamdiskProp;
load_properties_from_file(kDebugRamdiskProp, nullptr, &properties);
}
for (const auto& [name, value] : properties) {
std::string error;
if (PropertySet(name, value, &error) != PROP_SUCCESS) {
LOG(ERROR) << "Could not set '" << name << "' to '" << value
<< "' while loading .prop files" << error;
}
}
property_initialize_ro_product_props();
property_initialize_build_id();
property_derive_build_fingerprint();
property_derive_legacy_build_fingerprint();
property_initialize_ro_cpu_abilist();
update_sys_usb_config();
}
bool LoadPropertyInfoFromFile(const std::string& filename,
std::vector<PropertyInfoEntry>* property_infos) {
auto file_contents = std::string();
if (!ReadFileToString(filename, &file_contents)) {
PLOG(ERROR) << "Could not read properties from '" << filename << "'";
return false;
}
auto errors = std::vector<std::string>{};
bool require_prefix_or_exact = SelinuxGetVendorAndroidVersion() >= __ANDROID_API_R__;
ParsePropertyInfoFile(file_contents, require_prefix_or_exact, property_infos, &errors);
// Individual parsing errors are reported but do not cause a failed boot, which is what
// returning false would do here.
for (const auto& error : errors) {
LOG(ERROR) << "Could not read line from '" << filename << "': " << error;
}
return true;
}
void CreateSerializedPropertyInfo() {
auto property_infos = std::vector<PropertyInfoEntry>();
if (access("/system/etc/selinux/plat_property_contexts", R_OK) != -1) {
if (!LoadPropertyInfoFromFile("/system/etc/selinux/plat_property_contexts",
&property_infos)) {
return;
}
// Don't check for failure here, since we don't always have all of these partitions.
// E.g. In case of recovery, the vendor partition will not have mounted and we
// still need the system / platform properties to function.
if (access("/system_ext/etc/selinux/system_ext_property_contexts", R_OK) != -1) {
LoadPropertyInfoFromFile("/system_ext/etc/selinux/system_ext_property_contexts",
&property_infos);
}
if (!LoadPropertyInfoFromFile("/vendor/etc/selinux/vendor_property_contexts",
&property_infos)) {
// Fallback to nonplat_* if vendor_* doesn't exist.
LoadPropertyInfoFromFile("/vendor/etc/selinux/nonplat_property_contexts",
&property_infos);
}
if (access("/product/etc/selinux/product_property_contexts", R_OK) != -1) {
LoadPropertyInfoFromFile("/product/etc/selinux/product_property_contexts",
&property_infos);
}
if (access("/odm/etc/selinux/odm_property_contexts", R_OK) != -1) {
LoadPropertyInfoFromFile("/odm/etc/selinux/odm_property_contexts", &property_infos);
}
} else {
if (!LoadPropertyInfoFromFile("/plat_property_contexts", &property_infos)) {
return;
}
LoadPropertyInfoFromFile("/system_ext_property_contexts", &property_infos);
if (!LoadPropertyInfoFromFile("/vendor_property_contexts", &property_infos)) {
// Fallback to nonplat_* if vendor_* doesn't exist.
LoadPropertyInfoFromFile("/nonplat_property_contexts", &property_infos);
}
LoadPropertyInfoFromFile("/product_property_contexts", &property_infos);
LoadPropertyInfoFromFile("/odm_property_contexts", &property_infos);
}
auto serialized_contexts = std::string();
auto error = std::string();
if (!BuildTrie(property_infos, "u:object_r:default_prop:s0", "string", &serialized_contexts,
&error)) {
LOG(ERROR) << "Unable to serialize property contexts: " << error;
return;
}
constexpr static const char kPropertyInfosPath[] = "/dev/__properties__/property_info";
if (!WriteStringToFile(serialized_contexts, kPropertyInfosPath, 0444, 0, 0, false)) {
PLOG(ERROR) << "Unable to write serialized property infos to file";
}
selinux_android_restorecon(kPropertyInfosPath, 0);
}
static void ExportKernelBootProps() {
constexpr const char* UNSET = "";
struct {
const char* src_prop;
const char* dst_prop;
const char* default_value;
} prop_map[] = {
// clang-format off
{ "ro.boot.serialno", "ro.serialno", UNSET, },
{ "ro.boot.mode", "ro.bootmode", "unknown", },
{ "ro.boot.baseband", "ro.baseband", "unknown", },
{ "ro.boot.bootloader", "ro.bootloader", "unknown", },
{ "ro.boot.hardware", "ro.hardware", "unknown", },
{ "ro.boot.revision", "ro.revision", "0", },
// clang-format on
};
for (const auto& prop : prop_map) {
std::string value = GetProperty(prop.src_prop, prop.default_value);
if (value != UNSET) InitPropertySet(prop.dst_prop, value);
}
}
static void ProcessKernelDt() {
if (!is_android_dt_value_expected("compatible", "android,firmware")) {
return;
}
std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(get_android_dt_dir().c_str()), closedir);
if (!dir) return;
std::string dt_file;
struct dirent* dp;
while ((dp = readdir(dir.get())) != NULL) {
if (dp->d_type != DT_REG || !strcmp(dp->d_name, "compatible") ||
!strcmp(dp->d_name, "name")) {
continue;
}
std::string file_name = get_android_dt_dir() + dp->d_name;
android::base::ReadFileToString(file_name, &dt_file);
std::replace(dt_file.begin(), dt_file.end(), ',', '.');
InitPropertySet("ro.boot."s + dp->d_name, dt_file);
}
}
constexpr auto ANDROIDBOOT_PREFIX = "androidboot."sv;
static void ProcessKernelCmdline() {
ImportKernelCmdline([&](const std::string& key, const std::string& value) {
if (StartsWith(key, ANDROIDBOOT_PREFIX)) {
InitPropertySet("ro.boot." + key.substr(ANDROIDBOOT_PREFIX.size()), value);
}
});
}
static void ProcessBootconfig() {
ImportBootconfig([&](const std::string& key, const std::string& value) {
if (StartsWith(key, ANDROIDBOOT_PREFIX)) {
InitPropertySet("ro.boot." + key.substr(ANDROIDBOOT_PREFIX.size()), value);
}
});
}
void PropertyInit() {
selinux_callback cb;
cb.func_audit = PropertyAuditCallback;
selinux_set_callback(SELINUX_CB_AUDIT, cb);
mkdir("/dev/__properties__", S_IRWXU | S_IXGRP | S_IXOTH);
CreateSerializedPropertyInfo();
if (__system_property_area_init()) {
LOG(FATAL) << "Failed to initialize property area";
}
if (!property_info_area.LoadDefaultPath()) {
LOG(FATAL) << "Failed to load serialized property info file";
}
// If arguments are passed both on the command line and in DT,
// properties set in DT always have priority over the command-line ones.
ProcessKernelDt();
ProcessKernelCmdline();
ProcessBootconfig();
// Propagate the kernel variables to internal variables
// used by init as well as the current required properties.
ExportKernelBootProps();
PropertyLoadBootDefaults();
}
static void HandleInitSocket() {
auto message = ReadMessage(init_socket);
if (!message.ok()) {
LOG(ERROR) << "Could not read message from init_dedicated_recv_socket: " << message.error();
return;
}
auto init_message = InitMessage{};
if (!init_message.ParseFromString(*message)) {
LOG(ERROR) << "Could not parse message from init";
return;
}
switch (init_message.msg_case()) {
case InitMessage::kLoadPersistentProperties: {
load_override_properties();
// Read persistent properties after all default values have been loaded.
auto persistent_properties = LoadPersistentProperties();
for (const auto& persistent_property_record : persistent_properties.properties()) {
InitPropertySet(persistent_property_record.name(),
persistent_property_record.value());
}
InitPropertySet("ro.persistent_properties.ready", "true");
persistent_properties_loaded = true;
break;
}
default:
LOG(ERROR) << "Unknown message type from init: " << init_message.msg_case();
}
}
static void PropertyServiceThread() {
Epoll epoll;
if (auto result = epoll.Open(); !result.ok()) {
LOG(FATAL) << result.error();
}
if (auto result = epoll.RegisterHandler(property_set_fd, handle_property_set_fd);
!result.ok()) {
LOG(FATAL) << result.error();
}
if (auto result = epoll.RegisterHandler(init_socket, HandleInitSocket); !result.ok()) {
LOG(FATAL) << result.error();
}
while (true) {
auto pending_functions = epoll.Wait(std::nullopt);
if (!pending_functions.ok()) {
LOG(ERROR) << pending_functions.error();
} else {
for (const auto& function : *pending_functions) {
(*function)();
}
}
}
}
void StartPropertyService(int* epoll_socket) {
InitPropertySet("ro.property_service.version", "2");
int sockets[2];
if (socketpair(AF_UNIX, SOCK_SEQPACKET | SOCK_CLOEXEC, 0, sockets) != 0) {
PLOG(FATAL) << "Failed to socketpair() between property_service and init";
}
*epoll_socket = from_init_socket = sockets[0];
init_socket = sockets[1];
StartSendingMessages();
if (auto result = CreateSocket(PROP_SERVICE_NAME, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
false, 0666, 0, 0, {});
result.ok()) {
property_set_fd = *result;
} else {
LOG(FATAL) << "start_property_service socket creation failed: " << result.error();
}
listen(property_set_fd, 8);
auto new_thread = std::thread{PropertyServiceThread};
property_service_thread.swap(new_thread);
}
} // namespace init
} // namespace android
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