Merge "use a single file for storing persistent properties"

This commit is contained in:
Tom Cherry 2017-08-30 19:30:18 +00:00 committed by Gerrit Code Review
commit e1f9a58c86
5 changed files with 566 additions and 83 deletions

View file

@ -72,6 +72,7 @@ cc_library_static {
"import_parser.cpp",
"log.cpp",
"parser.cpp",
"persistent_properties.cpp",
"property_service.cpp",
"security.cpp",
"selinux.cpp",
@ -162,6 +163,7 @@ cc_test {
srcs: [
"devices_test.cpp",
"init_test.cpp",
"persistent_properties_test.cpp",
"property_service_test.cpp",
"result_test.cpp",
"rlimit_parser_test.cpp",

View file

@ -0,0 +1,341 @@
/*
* Copyright (C) 2017 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 "persistent_properties.h"
#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/system_properties.h>
#include <sys/types.h>
#include <memory>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include "util.h"
using android::base::ReadFdToString;
using android::base::StartsWith;
using android::base::WriteStringToFd;
using android::base::unique_fd;
namespace android {
namespace init {
std::string persistent_property_filename = "/data/property/persistent_properties";
namespace {
constexpr const uint32_t kMagic = 0x8495E0B4;
constexpr const char kLegacyPersistentPropertyDir[] = "/data/property";
Result<std::vector<std::pair<std::string, std::string>>> LoadLegacyPersistentProperties() {
std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(kLegacyPersistentPropertyDir), closedir);
if (!dir) {
return ErrnoError() << "Unable to open persistent property directory \""
<< kLegacyPersistentPropertyDir << "\"";
}
std::vector<std::pair<std::string, std::string>> persistent_properties;
dirent* entry;
while ((entry = readdir(dir.get())) != nullptr) {
if (!StartsWith(entry->d_name, "persist.")) {
continue;
}
if (entry->d_type != DT_REG) {
continue;
}
unique_fd fd(openat(dirfd(dir.get()), entry->d_name, O_RDONLY | O_NOFOLLOW));
if (fd == -1) {
PLOG(ERROR) << "Unable to open persistent property file \"" << entry->d_name << "\"";
continue;
}
struct stat sb;
if (fstat(fd, &sb) == -1) {
PLOG(ERROR) << "fstat on property file \"" << entry->d_name << "\" failed";
continue;
}
// File must not be accessible to others, be owned by root/root, and
// not be a hard link to any other file.
if (((sb.st_mode & (S_IRWXG | S_IRWXO)) != 0) || sb.st_uid != 0 || sb.st_gid != 0 ||
sb.st_nlink != 1) {
PLOG(ERROR) << "skipping insecure property file " << entry->d_name
<< " (uid=" << sb.st_uid << " gid=" << sb.st_gid << " nlink=" << sb.st_nlink
<< " mode=" << std::oct << sb.st_mode << ")";
continue;
}
std::string value;
if (ReadFdToString(fd, &value)) {
persistent_properties.emplace_back(entry->d_name, value);
} else {
PLOG(ERROR) << "Unable to read persistent property file " << entry->d_name;
}
}
return persistent_properties;
}
void RemoveLegacyPersistentPropertyFiles() {
std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(kLegacyPersistentPropertyDir), closedir);
if (!dir) {
PLOG(ERROR) << "Unable to open persistent property directory \""
<< kLegacyPersistentPropertyDir << "\"";
return;
}
dirent* entry;
while ((entry = readdir(dir.get())) != nullptr) {
if (!StartsWith(entry->d_name, "persist.")) {
continue;
}
if (entry->d_type != DT_REG) {
continue;
}
unlinkat(dirfd(dir.get()), entry->d_name, 0);
}
}
std::vector<std::pair<std::string, std::string>> LoadPersistentPropertiesFromMemory() {
std::vector<std::pair<std::string, std::string>> properties;
__system_property_foreach(
[](const prop_info* pi, void* cookie) {
__system_property_read_callback(
pi,
[](void* cookie, const char* name, const char* value, unsigned serial) {
if (StartsWith(name, "persist.")) {
auto properties =
reinterpret_cast<std::vector<std::pair<std::string, std::string>>*>(
cookie);
properties->emplace_back(name, value);
}
},
cookie);
},
&properties);
return properties;
}
class PersistentPropertyFileParser {
public:
PersistentPropertyFileParser(const std::string& contents) : contents_(contents), position_(0) {}
Result<std::vector<std::pair<std::string, std::string>>> Parse();
private:
Result<std::string> ReadString();
Result<uint32_t> ReadUint32();
const std::string& contents_;
size_t position_;
};
Result<std::vector<std::pair<std::string, std::string>>> PersistentPropertyFileParser::Parse() {
std::vector<std::pair<std::string, std::string>> result;
if (auto magic = ReadUint32(); magic) {
if (*magic != kMagic) {
return Error() << "Magic value '0x" << std::hex << *magic
<< "' does not match expected value '0x" << kMagic << "'";
}
} else {
return Error() << "Could not read magic value: " << magic.error();
}
if (auto version = ReadUint32(); version) {
if (*version != 1) {
return Error() << "Version '" << *version
<< "' does not match any compatible version: (1)";
}
} else {
return Error() << "Could not read version: " << version.error();
}
auto num_properties = ReadUint32();
if (!num_properties) {
return Error() << "Could not read num_properties: " << num_properties.error();
}
while (position_ < contents_.size()) {
auto key = ReadString();
if (!key) {
return Error() << "Could not read key: " << key.error();
}
if (!StartsWith(*key, "persist.")) {
return Error() << "Property '" << *key << "' does not starts with 'persist.'";
}
auto value = ReadString();
if (!value) {
return Error() << "Could not read value: " << value.error();
}
result.emplace_back(*key, *value);
}
if (result.size() != *num_properties) {
return Error() << "Mismatch of number of persistent properties read, " << result.size()
<< " and number of persistent properties expected, " << *num_properties;
}
return result;
}
Result<std::string> PersistentPropertyFileParser::ReadString() {
auto string_length = ReadUint32();
if (!string_length) {
return Error() << "Could not read size for string";
}
if (position_ + *string_length > contents_.size()) {
return Error() << "String size would cause it to overflow the input buffer";
}
auto result = std::string(contents_, position_, *string_length);
position_ += *string_length;
return result;
}
Result<uint32_t> PersistentPropertyFileParser::ReadUint32() {
if (position_ + 3 > contents_.size()) {
return Error() << "Input buffer not large enough to read uint32_t";
}
uint32_t result = *reinterpret_cast<const uint32_t*>(&contents_[position_]);
position_ += sizeof(uint32_t);
return result;
}
} // namespace
Result<std::vector<std::pair<std::string, std::string>>> LoadPersistentPropertyFile() {
const std::string temp_filename = persistent_property_filename + ".tmp";
if (access(temp_filename.c_str(), F_OK) == 0) {
LOG(INFO)
<< "Found temporary property file while attempting to persistent system properties"
" a previous persistent property write may have failed";
unlink(temp_filename.c_str());
}
auto file_contents = ReadFile(persistent_property_filename);
if (!file_contents) {
return Error() << "Unable to read persistent property file: " << file_contents.error();
}
auto parsed_contents = PersistentPropertyFileParser(*file_contents).Parse();
if (!parsed_contents) {
// If the file cannot be parsed, then we don't have any recovery mechanisms, so we delete
// it to allow for future writes to take place successfully.
unlink(persistent_property_filename.c_str());
return Error() << "Unable to parse persistent property file: " << parsed_contents.error();
}
return parsed_contents;
}
std::string GenerateFileContents(
const std::vector<std::pair<std::string, std::string>>& persistent_properties) {
std::string result;
uint32_t magic = kMagic;
result.append(reinterpret_cast<char*>(&magic), sizeof(uint32_t));
uint32_t version = 1;
result.append(reinterpret_cast<char*>(&version), sizeof(uint32_t));
uint32_t num_properties = persistent_properties.size();
result.append(reinterpret_cast<char*>(&num_properties), sizeof(uint32_t));
for (const auto& [key, value] : persistent_properties) {
uint32_t key_length = key.length();
result.append(reinterpret_cast<char*>(&key_length), sizeof(uint32_t));
result.append(key);
uint32_t value_length = value.length();
result.append(reinterpret_cast<char*>(&value_length), sizeof(uint32_t));
result.append(value);
}
return result;
}
Result<Success> WritePersistentPropertyFile(
const std::vector<std::pair<std::string, std::string>>& persistent_properties) {
auto file_contents = GenerateFileContents(persistent_properties);
const std::string temp_filename = persistent_property_filename + ".tmp";
unique_fd fd(TEMP_FAILURE_RETRY(
open(temp_filename.c_str(), O_WRONLY | O_CREAT | O_NOFOLLOW | O_TRUNC | O_CLOEXEC, 0600)));
if (fd == -1) {
return ErrnoError() << "Could not open temporary properties file";
}
if (!WriteStringToFd(file_contents, fd)) {
return ErrnoError() << "Unable to write file contents";
}
fsync(fd);
fd.reset();
if (rename(temp_filename.c_str(), persistent_property_filename.c_str())) {
int saved_errno = errno;
unlink(temp_filename.c_str());
return Error(saved_errno) << "Unable to rename persistent property file";
}
return Success();
}
// Persistent properties are not written often, so we rather not keep any data in memory and read
// then rewrite the persistent property file for each update.
void WritePersistentProperty(const std::string& name, const std::string& value) {
auto persistent_properties = LoadPersistentPropertyFile();
if (!persistent_properties) {
LOG(ERROR) << "Recovering persistent properties from memory: "
<< persistent_properties.error();
persistent_properties = LoadPersistentPropertiesFromMemory();
}
auto it = std::find_if(persistent_properties->begin(), persistent_properties->end(),
[&name](const auto& entry) { return entry.first == name; });
if (it != persistent_properties->end()) {
*it = {name, value};
} else {
persistent_properties->emplace_back(name, value);
}
if (auto result = WritePersistentPropertyFile(*persistent_properties); !result) {
LOG(ERROR) << "Could not store persistent property: " << result.error();
}
}
std::vector<std::pair<std::string, std::string>> LoadPersistentProperties() {
auto persistent_properties = LoadPersistentPropertyFile();
if (!persistent_properties) {
LOG(ERROR) << "Could not load single persistent property file, trying legacy directory: "
<< persistent_properties.error();
persistent_properties = LoadLegacyPersistentProperties();
if (!persistent_properties) {
LOG(ERROR) << "Unable to load legacy persistent properties: "
<< persistent_properties.error();
return {};
}
if (auto result = WritePersistentPropertyFile(*persistent_properties); result) {
RemoveLegacyPersistentPropertyFiles();
} else {
LOG(ERROR) << "Unable to write single persistent property file: " << result.error();
// Fall through so that we still set the properties that we've read.
}
}
return *persistent_properties;
}
} // namespace init
} // namespace android

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@ -0,0 +1,42 @@
/*
* Copyright (C) 2017 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.
*/
#ifndef _INIT_PERSISTENT_PROPERTIES_H
#define _INIT_PERSISTENT_PROPERTIES_H
#include <string>
#include <vector>
#include "result.h"
namespace android {
namespace init {
std::vector<std::pair<std::string, std::string>> LoadPersistentProperties();
void WritePersistentProperty(const std::string& name, const std::string& value);
// Exposed only for testing
Result<std::vector<std::pair<std::string, std::string>>> LoadPersistentPropertyFile();
std::string GenerateFileContents(
const std::vector<std::pair<std::string, std::string>>& persistent_properties);
Result<Success> WritePersistentPropertyFile(
const std::vector<std::pair<std::string, std::string>>& persistent_properties);
extern std::string persistent_property_filename;
} // namespace init
} // namespace android
#endif

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@ -0,0 +1,173 @@
/*
* Copyright (C) 2017 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 "persistent_properties.h"
#include <errno.h>
#include <android-base/test_utils.h>
#include <gtest/gtest.h>
#include "util.h"
using namespace std::string_literals;
namespace android {
namespace init {
TEST(persistent_properties, GeneratedContents) {
const std::vector<std::pair<std::string, std::string>> persistent_properties = {
{"persist.abc", ""},
{"persist.def", "test_success"},
};
auto generated_contents = GenerateFileContents(persistent_properties);
// Manually serialized contents below:
std::string file_contents;
// All values below are written and read as little endian.
// Add magic value: 0x8495E0B4
file_contents += "\xB4\xE0\x95\x84"s;
// Add version: 1
file_contents += "\x01\x00\x00\x00"s;
// Add number of properties: 2
file_contents += "\x02\x00\x00\x00"s;
// Add first key: persist.abc
file_contents += "\x0B\x00\x00\x00persist.abc"s;
// Add first value: (empty string)
file_contents += "\x00\x00\x00\x00"s;
// Add second key: persist.def
file_contents += "\x0B\x00\x00\x00persist.def"s;
// Add second value: test_success
file_contents += "\x0C\x00\x00\x00test_success"s;
EXPECT_EQ(file_contents, generated_contents);
}
TEST(persistent_properties, EndToEnd) {
TemporaryFile tf;
ASSERT_TRUE(tf.fd != -1);
persistent_property_filename = tf.path;
std::vector<std::pair<std::string, std::string>> persistent_properties = {
{"persist.sys.locale", "en-US"},
{"persist.sys.timezone", "America/Los_Angeles"},
{"persist.test.empty.value", ""},
{"persist.test.new.line", "abc\n\n\nabc"},
{"persist.test.numbers", "1234567890"},
{"persist.test.non.ascii", "\x00\x01\x02\xFF\xFE\xFD\x7F\x8F\x9F"},
// We don't currently allow for non-ascii keys for system properties, but this is a policy
// decision, not a technical limitation.
{"persist.\x00\x01\x02\xFF\xFE\xFD\x7F\x8F\x9F", "non-ascii-key"},
};
ASSERT_TRUE(WritePersistentPropertyFile(persistent_properties));
auto read_back_properties = LoadPersistentProperties();
EXPECT_EQ(persistent_properties, read_back_properties);
}
TEST(persistent_properties, BadMagic) {
TemporaryFile tf;
ASSERT_TRUE(tf.fd != -1);
persistent_property_filename = tf.path;
ASSERT_TRUE(WriteFile(tf.path, "ab"));
auto read_back_properties = LoadPersistentPropertyFile();
ASSERT_FALSE(read_back_properties);
EXPECT_EQ(
"Unable to parse persistent property file: Could not read magic value: Input buffer not "
"large enough to read uint32_t",
read_back_properties.error_string());
ASSERT_TRUE(WriteFile(tf.path, "\xFF\xFF\xFF\xFF"));
read_back_properties = LoadPersistentPropertyFile();
ASSERT_FALSE(read_back_properties);
EXPECT_EQ(
"Unable to parse persistent property file: Magic value '0xffffffff' does not match "
"expected value '0x8495e0b4'",
read_back_properties.error_string());
}
TEST(persistent_properties, AddProperty) {
TemporaryFile tf;
ASSERT_TRUE(tf.fd != -1);
persistent_property_filename = tf.path;
std::vector<std::pair<std::string, std::string>> persistent_properties = {
{"persist.sys.timezone", "America/Los_Angeles"},
};
ASSERT_TRUE(WritePersistentPropertyFile(persistent_properties));
WritePersistentProperty("persist.sys.locale", "pt-BR");
std::vector<std::pair<std::string, std::string>> persistent_properties_expected = {
{"persist.sys.timezone", "America/Los_Angeles"},
{"persist.sys.locale", "pt-BR"},
};
auto read_back_properties = LoadPersistentProperties();
EXPECT_EQ(persistent_properties_expected, read_back_properties);
}
TEST(persistent_properties, UpdateProperty) {
TemporaryFile tf;
ASSERT_TRUE(tf.fd != -1);
persistent_property_filename = tf.path;
std::vector<std::pair<std::string, std::string>> persistent_properties = {
{"persist.sys.locale", "en-US"},
{"persist.sys.timezone", "America/Los_Angeles"},
};
ASSERT_TRUE(WritePersistentPropertyFile(persistent_properties));
WritePersistentProperty("persist.sys.locale", "pt-BR");
std::vector<std::pair<std::string, std::string>> persistent_properties_expected = {
{"persist.sys.locale", "pt-BR"},
{"persist.sys.timezone", "America/Los_Angeles"},
};
auto read_back_properties = LoadPersistentProperties();
EXPECT_EQ(persistent_properties_expected, read_back_properties);
}
TEST(persistent_properties, UpdatePropertyBadParse) {
TemporaryFile tf;
ASSERT_TRUE(tf.fd != -1);
persistent_property_filename = tf.path;
ASSERT_TRUE(WriteFile(tf.path, "ab"));
WritePersistentProperty("persist.sys.locale", "pt-BR");
auto read_back_properties = LoadPersistentProperties();
EXPECT_GT(read_back_properties.size(), 0U);
auto it = std::find_if(
read_back_properties.begin(), read_back_properties.end(), [](const auto& entry) {
return entry.first == "persist.sys.locale" && entry.second == "pt-BR";
});
EXPECT_FALSE(it == read_back_properties.end());
}
} // namespace init
} // namespace android

View file

@ -17,7 +17,6 @@
#include "property_service.h"
#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
@ -54,17 +53,17 @@
#include <selinux/selinux.h>
#include "init.h"
#include "persistent_properties.h"
#include "util.h"
using android::base::Timer;
#define PERSISTENT_PROPERTY_DIR "/data/property"
#define RECOVERY_MOUNT_POINT "/recovery"
namespace android {
namespace init {
static int persistent_properties_loaded = 0;
static bool persistent_properties_loaded = false;
static int property_set_fd = -1;
@ -120,29 +119,6 @@ static int check_control_mac_perms(const char *name, char *sctx, struct ucred *c
return check_mac_perms(ctl_name, sctx, cr);
}
static void write_persistent_property(const char *name, const char *value)
{
char tempPath[PATH_MAX];
char path[PATH_MAX];
int fd;
snprintf(tempPath, sizeof(tempPath), "%s/.temp.XXXXXX", PERSISTENT_PROPERTY_DIR);
fd = mkstemp(tempPath);
if (fd < 0) {
PLOG(ERROR) << "Unable to write persistent property to temp file " << tempPath;
return;
}
write(fd, value, strlen(value));
fsync(fd);
close(fd);
snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, name);
if (rename(tempPath, path)) {
PLOG(ERROR) << "Unable to rename persistent property file " << tempPath << " to " << path;
unlink(tempPath);
}
}
bool is_legal_property_name(const std::string& name) {
size_t namelen = name.size();
@ -204,7 +180,7 @@ static uint32_t PropertySetImpl(const std::string& name, const std::string& valu
// 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 && android::base::StartsWith(name, "persist.")) {
write_persistent_property(name.c_str(), value.c_str());
WritePersistentProperty(name, value);
}
property_changed(name, value);
return PROP_SUCCESS;
@ -599,61 +575,6 @@ static void load_properties_from_file(const char* filename, const char* filter)
LOG(VERBOSE) << "(Loading properties from " << filename << " took " << t << ".)";
}
static void load_persistent_properties() {
persistent_properties_loaded = 1;
std::unique_ptr<DIR, int(*)(DIR*)> dir(opendir(PERSISTENT_PROPERTY_DIR), closedir);
if (!dir) {
PLOG(ERROR) << "Unable to open persistent property directory \""
<< PERSISTENT_PROPERTY_DIR << "\"";
return;
}
struct dirent* entry;
while ((entry = readdir(dir.get())) != NULL) {
if (strncmp("persist.", entry->d_name, strlen("persist."))) {
continue;
}
if (entry->d_type != DT_REG) {
continue;
}
// Open the file and read the property value.
int fd = openat(dirfd(dir.get()), entry->d_name, O_RDONLY | O_NOFOLLOW);
if (fd == -1) {
PLOG(ERROR) << "Unable to open persistent property file \"" << entry->d_name << "\"";
continue;
}
struct stat sb;
if (fstat(fd, &sb) == -1) {
PLOG(ERROR) << "fstat on property file \"" << entry->d_name << "\" failed";
close(fd);
continue;
}
// File must not be accessible to others, be owned by root/root, and
// not be a hard link to any other file.
if (((sb.st_mode & (S_IRWXG | S_IRWXO)) != 0) || sb.st_uid != 0 || sb.st_gid != 0 || sb.st_nlink != 1) {
PLOG(ERROR) << "skipping insecure property file " << entry->d_name
<< " (uid=" << sb.st_uid << " gid=" << sb.st_gid
<< " nlink=" << sb.st_nlink << " mode=" << std::oct << sb.st_mode << ")";
close(fd);
continue;
}
char value[PROP_VALUE_MAX];
int length = read(fd, value, sizeof(value) - 1);
if (length >= 0) {
value[length] = 0;
property_set(entry->d_name, value);
} else {
PLOG(ERROR) << "Unable to read persistent property file " << entry->d_name;
}
close(fd);
}
}
// 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
@ -703,7 +624,11 @@ void load_persist_props(void) {
load_override_properties();
/* Read persistent properties after all default values have been loaded. */
load_persistent_properties();
auto persistent_properties = LoadPersistentProperties();
for (const auto& [name, value] : persistent_properties) {
property_set(name, value);
}
persistent_properties_loaded = true;
property_set("ro.persistent_properties.ready", "true");
}