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platform_system_core/init/property_service.cpp
Dennis Shen 79283ef377 Move staging value application logic to persistent_properties and add 
unit tests

1, Previous implementation has the staged prop application done in
property_service, which caused a number of unnecessary changes which
including exposing apis like AddPersistentProperty. In addition, it made
the property_service logic complicated. A better design is to have the
staged value application done while reading the persistent properties
from file. This way, no change to property service. In addition, unit
test is much cleaner and efficient.

2, add a unit test to lock down the behavior. Specifically, it locks down that when a prop is staged, it should be applied the next time when the persistent prop is loaded. In addition, it should lock down that other persistent props are not overwritten.

Bug: b/307752841, b/300111812, b/306062513

Change-Id: I43c603efbb803195065dda3f0bc2145716302bbc
2023-11-02 14:17:33 +00:00

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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/result.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <fs_mgr.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::ErrnoError;
using android::base::Error;
using android::base::GetProperty;
using android::base::ParseInt;
using android::base::ReadFileToString;
using android::base::Result;
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 {
class PersistWriteThread;
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;
constexpr auto API_LEVEL_CURRENT = 10000;
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 std::unique_ptr<PersistWriteThread> persist_write_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;
}
void NotifyPropertyChange(const std::string& name, const std::string& 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);
}
}
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() = default;
SocketConnection(int socket, const ucred& cred) : socket_(socket), cred_(cred) {}
SocketConnection(SocketConnection&&) = default;
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_.get(), &value, sizeof(value), 0));
return result == sizeof(value);
}
bool GetSourceContext(std::string* source_context) const {
char* c_source_context = nullptr;
if (getpeercon(socket_.get(), &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_; }
SocketConnection& operator=(SocketConnection&&) = default;
private:
bool PollIn(uint32_t* timeout_ms) {
struct pollfd ufd = {
.fd = socket_.get(),
.events = POLLIN,
};
while (*timeout_ms > 0) {
auto start_time = std::chrono::steady_clock::now();
int nr = poll(&ufd, 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_.get(), 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_COPY_AND_ASSIGN(SocketConnection);
};
class PersistWriteThread {
public:
PersistWriteThread();
void Write(std::string name, std::string value, SocketConnection socket);
private:
void Work();
private:
std::thread thread_;
std::mutex mutex_;
std::condition_variable cv_;
std::deque<std::tuple<std::string, std::string, SocketConnection>> work_;
};
static std::optional<uint32_t> PropertySet(const std::string& name, const std::string& value,
SocketConnection* socket, 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};
}
}
bool need_persist = StartsWith(name, "persist.") || StartsWith(name, "next_boot.");
if (socket && persistent_properties_loaded && need_persist) {
if (persist_write_thread) {
persist_write_thread->Write(name, value, std::move(*socket));
return {};
}
WritePersistentProperty(name, value);
}
NotifyPropertyChange(name, value);
return {PROP_SUCCESS};
}
// Helper for PropertySet, for the case where no socket is used, and therefore an asynchronous
// return is not possible.
static uint32_t PropertySetNoSocket(const std::string& name, const std::string& value,
std::string* error) {
auto ret = PropertySet(name, value, nullptr, error);
CHECK(ret.has_value());
return *ret;
}
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*, or std::nullopt
// if asynchronous.
std::optional<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 == "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, socket, error);
}
// Helper for HandlePropertySet, for the case where no socket is used, and
// therefore an asynchronous return is not possible.
uint32_t HandlePropertySetNoSocket(const std::string& name, const std::string& value,
const std::string& source_context, const ucred& cr,
std::string* error) {
auto ret = HandlePropertySet(name, value, source_context, cr, nullptr, error);
CHECK(ret.has_value());
return *ret;
}
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;
auto result = HandlePropertySetNoSocket(prop_name, prop_value, source_context, cr, &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;
}
// HandlePropertySet takes ownership of the socket if the set is handled asynchronously.
const auto& cr = socket.cred();
std::string error;
auto result = HandlePropertySet(name, value, source_context, cr, &socket, &error);
if (!result) {
// Result will be sent after completion.
return;
}
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) {
ucred cr = {.pid = 1, .uid = 0, .gid = 0};
std::string error;
auto result = HandlePropertySetNoSocket(name, value, kInitContext, cr, &error);
if (result != PROP_SUCCESS) {
LOG(ERROR) << "Init cannot set '" << name << "' to '" << value << "': " << error;
}
return result;
}
static Result<void> 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;
}
if (auto res = load_properties_from_file(expanded_filename->c_str(), key, properties);
!res.ok()) {
LOG(WARNING) << res.error();
}
} 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 Result<void> 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()) {
return Error() << "Couldn't load property file '" << filename
<< "': " << file_contents.error();
}
file_contents->push_back('\n');
LoadProperties(file_contents->data(), filter, filename, properties);
LOG(VERBOSE) << "(Loading properties from " << filename << " took " << t << ".)";
return {};
}
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;
}
if (auto res = load_properties_from_file(prop.c_str(), nullptr, properties); !res.ok()) {
LOG(WARNING) << res.error();
}
}
// 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 (PropertySetNoSocket(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;
auto res = PropertySetNoSocket(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 = PropertySetNoSocket(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;
auto res = PropertySetNoSocket(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;
auto res = PropertySetNoSocket(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;
auto res = PropertySetNoSocket(prop, prop_val, &error);
if (res != PROP_SUCCESS) {
LOG(ERROR) << "Error setting property '" << prop << "': err=" << res << " (" << error
<< ")";
}
}
}
static int read_api_level_props(const std::vector<std::string>& api_level_props) {
int api_level = API_LEVEL_CURRENT;
for (const auto& api_level_prop : api_level_props) {
api_level = android::base::GetIntProperty(api_level_prop, API_LEVEL_CURRENT);
if (api_level != API_LEVEL_CURRENT) {
break;
}
}
return api_level;
}
static void property_initialize_ro_vendor_api_level() {
// ro.vendor.api_level shows the api_level that the vendor images (vendor, odm, ...) are
// required to support.
constexpr auto VENDOR_API_LEVEL_PROP = "ro.vendor.api_level";
// Api level properties of the board. The order of the properties must be kept.
std::vector<std::string> BOARD_API_LEVEL_PROPS = {"ro.board.api_level",
"ro.board.first_api_level"};
// Api level properties of the device. The order of the properties must be kept.
std::vector<std::string> DEVICE_API_LEVEL_PROPS = {"ro.product.first_api_level",
"ro.build.version.sdk"};
int api_level = std::min(read_api_level_props(BOARD_API_LEVEL_PROPS),
read_api_level_props(DEVICE_API_LEVEL_PROPS));
std::string error;
auto res = PropertySetNoSocket(VENDOR_API_LEVEL_PROP, std::to_string(api_level), &error);
if (res != PROP_SUCCESS) {
LOG(ERROR) << "Failed to set " << VENDOR_API_LEVEL_PROP << " with " << api_level << ": "
<< error << "(" << res << ")";
}
}
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()) {
if (auto res = load_properties_from_file("/prop.default", nullptr, &properties);
!res.ok()) {
LOG(ERROR) << res.error();
}
}
// /<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).ok()) {
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);
// system should have build.prop, unlike the other partitions
if (auto res = load_properties_from_file("/system/build.prop", nullptr, &properties);
!res.ok()) {
LOG(WARNING) << res.error();
}
load_properties_from_partition("system_ext", /* support_legacy_path_until */ 30);
load_properties_from_file("/system_dlkm/etc/build.prop", nullptr, &properties);
// 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;
if (auto res = load_properties_from_file(kDebugRamdiskProp, nullptr, &properties);
!res.ok()) {
LOG(WARNING) << res.error();
}
}
for (const auto& [name, value] : properties) {
std::string error;
if (PropertySetNoSocket(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();
property_initialize_ro_vendor_api_level();
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 (access("/vendor/etc/selinux/vendor_property_contexts", R_OK) != -1) {
LoadPropertyInfoFromFile("/vendor/etc/selinux/vendor_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);
LoadPropertyInfoFromFile("/vendor_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(android::fs_mgr::GetAndroidDtDir().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 = android::fs_mgr::GetAndroidDtDir() + 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() {
android::fs_mgr::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() {
android::fs_mgr::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();
auto persistent_properties = LoadPersistentProperties();
for (const auto& property_record : persistent_properties.properties()) {
auto const& prop_name = property_record.name();
auto const& prop_value = property_record.value();
InitPropertySet(prop_name, prop_value);
}
// Apply debug ramdisk special settings after persistent properties are loaded.
if (android::base::GetBoolProperty("ro.force.debuggable", false)) {
// Always enable usb adb if device is booted with debug ramdisk.
update_sys_usb_config();
}
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 epoll_result = epoll.Wait(std::nullopt);
if (!epoll_result.ok()) {
LOG(ERROR) << epoll_result.error();
}
}
}
PersistWriteThread::PersistWriteThread() {
auto new_thread = std::thread([this]() -> void { Work(); });
thread_.swap(new_thread);
}
void PersistWriteThread::Work() {
while (true) {
std::tuple<std::string, std::string, SocketConnection> item;
// Grab the next item within the lock.
{
std::unique_lock<std::mutex> lock(mutex_);
while (work_.empty()) {
cv_.wait(lock);
}
item = std::move(work_.front());
work_.pop_front();
}
// Perform write/fsync outside the lock.
WritePersistentProperty(std::get<0>(item), std::get<1>(item));
NotifyPropertyChange(std::get<0>(item), std::get<1>(item));
SocketConnection& socket = std::get<2>(item);
socket.SendUint32(PROP_SUCCESS);
}
}
void PersistWriteThread::Write(std::string name, std::string value, SocketConnection socket) {
{
std::unique_lock<std::mutex> lock(mutex_);
work_.emplace_back(std::move(name), std::move(value), std::move(socket));
}
cv_.notify_all();
}
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,
/*passcred=*/false, /*should_listen=*/false, 0666, /*uid=*/0,
/*gid=*/0, /*socketcon=*/{});
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);
auto async_persist_writes =
android::base::GetBoolProperty("ro.property_service.async_persist_writes", false);
if (async_persist_writes) {
persist_write_thread = std::make_unique<PersistWriteThread>();
}
}
} // namespace init
} // namespace android
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