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platform_system_core/init/util.cpp
Jiyong Park 3b3d87de79 Don't create vendor_init in microdroid 
vendor_init is a subcontext of init which is responsible for handling
the vendor-defined services and vendor-defined actions. This is mainly
to enforce the Treble architecture in which the vendor components are
provided with a less-privileged context than the system components
because they are less-trusted.

However, in case of microdroid, both the system and the vendor
partitions are from the same entity. As VMs don't have direct access to
any of the underlying hardware, the vendor partition is targeting the
virtual platform, not the real hw platform. There really is no need for
the discrimination.

This CL disables the creation of the vendor_init subcontext when init
runs in microdroid.

Bug: 201363575
Test: atest MicrodroidHostTestCases
Change-Id: Ie5e47d84e9e245565239b4f2159e8182b457699d
2021-09-29 21:35:08 +09:00

766 lines
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/*
* Copyright (C) 2008 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 "util.h"
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <time.h>
#include <unistd.h>
#include <thread>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/scopeguard.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <cutils/sockets.h>
#include <selinux/android.h>
#ifdef INIT_FULL_SOURCES
#include <android/api-level.h>
#include <sys/system_properties.h>
#include "reboot_utils.h"
#include "selabel.h"
#include "selinux.h"
#else
#include "host_init_stubs.h"
#endif
using android::base::boot_clock;
using android::base::StartsWith;
using namespace std::literals::string_literals;
namespace android {
namespace init {
const std::string kDefaultAndroidDtDir("/proc/device-tree/firmware/android/");
void (*trigger_shutdown)(const std::string& command) = nullptr;
// DecodeUid() - decodes and returns the given string, which can be either the
// numeric or name representation, into the integer uid or gid.
Result<uid_t> DecodeUid(const std::string& name) {
if (isalpha(name[0])) {
passwd* pwd = getpwnam(name.c_str());
if (!pwd) return ErrnoError() << "getpwnam failed";
return pwd->pw_uid;
}
errno = 0;
uid_t result = static_cast<uid_t>(strtoul(name.c_str(), 0, 0));
if (errno) return ErrnoError() << "strtoul failed";
return result;
}
/*
* CreateSocket - creates a Unix domain socket in ANDROID_SOCKET_DIR
* ("/dev/socket") as dictated in init.rc. This socket is inherited by the
* daemon. We communicate the file descriptor's value via the environment
* variable ANDROID_SOCKET_ENV_PREFIX<name> ("ANDROID_SOCKET_foo").
*/
Result<int> CreateSocket(const std::string& name, int type, bool passcred, mode_t perm, uid_t uid,
gid_t gid, const std::string& socketcon) {
if (!socketcon.empty()) {
if (setsockcreatecon(socketcon.c_str()) == -1) {
return ErrnoError() << "setsockcreatecon(\"" << socketcon << "\") failed";
}
}
android::base::unique_fd fd(socket(PF_UNIX, type, 0));
if (fd < 0) {
return ErrnoError() << "Failed to open socket '" << name << "'";
}
if (!socketcon.empty()) setsockcreatecon(nullptr);
struct sockaddr_un addr;
memset(&addr, 0 , sizeof(addr));
addr.sun_family = AF_UNIX;
snprintf(addr.sun_path, sizeof(addr.sun_path), ANDROID_SOCKET_DIR "/%s", name.c_str());
if ((unlink(addr.sun_path) != 0) && (errno != ENOENT)) {
return ErrnoError() << "Failed to unlink old socket '" << name << "'";
}
std::string secontext;
if (SelabelLookupFileContext(addr.sun_path, S_IFSOCK, &secontext) && !secontext.empty()) {
setfscreatecon(secontext.c_str());
}
if (passcred) {
int on = 1;
if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on))) {
return ErrnoError() << "Failed to set SO_PASSCRED '" << name << "'";
}
}
int ret = bind(fd, (struct sockaddr *) &addr, sizeof (addr));
int savederrno = errno;
if (!secontext.empty()) {
setfscreatecon(nullptr);
}
auto guard = android::base::make_scope_guard([&addr] { unlink(addr.sun_path); });
if (ret) {
errno = savederrno;
return ErrnoError() << "Failed to bind socket '" << name << "'";
}
if (lchown(addr.sun_path, uid, gid)) {
return ErrnoError() << "Failed to lchown socket '" << addr.sun_path << "'";
}
if (fchmodat(AT_FDCWD, addr.sun_path, perm, AT_SYMLINK_NOFOLLOW)) {
return ErrnoError() << "Failed to fchmodat socket '" << addr.sun_path << "'";
}
LOG(INFO) << "Created socket '" << addr.sun_path << "'"
<< ", mode " << std::oct << perm << std::dec
<< ", user " << uid
<< ", group " << gid;
guard.Disable();
return fd.release();
}
Result<std::string> ReadFile(const std::string& path) {
android::base::unique_fd fd(
TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC)));
if (fd == -1) {
return ErrnoError() << "open() failed";
}
// For security reasons, disallow world-writable
// or group-writable files.
struct stat sb;
if (fstat(fd, &sb) == -1) {
return ErrnoError() << "fstat failed()";
}
if ((sb.st_mode & (S_IWGRP | S_IWOTH)) != 0) {
return Error() << "Skipping insecure file";
}
std::string content;
if (!android::base::ReadFdToString(fd, &content)) {
return ErrnoError() << "Unable to read file contents";
}
return content;
}
static int OpenFile(const std::string& path, int flags, mode_t mode) {
std::string secontext;
if (SelabelLookupFileContext(path, mode, &secontext) && !secontext.empty()) {
setfscreatecon(secontext.c_str());
}
int rc = open(path.c_str(), flags, mode);
if (!secontext.empty()) {
int save_errno = errno;
setfscreatecon(nullptr);
errno = save_errno;
}
return rc;
}
Result<void> WriteFile(const std::string& path, const std::string& content) {
android::base::unique_fd fd(TEMP_FAILURE_RETRY(
OpenFile(path, O_WRONLY | O_CREAT | O_NOFOLLOW | O_TRUNC | O_CLOEXEC, 0600)));
if (fd == -1) {
return ErrnoError() << "open() failed";
}
if (!android::base::WriteStringToFd(content, fd)) {
return ErrnoError() << "Unable to write file contents";
}
return {};
}
bool mkdir_recursive(const std::string& path, mode_t mode) {
std::string::size_type slash = 0;
while ((slash = path.find('/', slash + 1)) != std::string::npos) {
auto directory = path.substr(0, slash);
struct stat info;
if (stat(directory.c_str(), &info) != 0) {
auto ret = make_dir(directory, mode);
if (!ret && errno != EEXIST) return false;
}
}
auto ret = make_dir(path, mode);
if (!ret && errno != EEXIST) return false;
return true;
}
int wait_for_file(const char* filename, std::chrono::nanoseconds timeout) {
android::base::Timer t;
while (t.duration() < timeout) {
struct stat sb;
if (stat(filename, &sb) != -1) {
LOG(INFO) << "wait for '" << filename << "' took " << t;
return 0;
}
std::this_thread::sleep_for(10ms);
}
LOG(WARNING) << "wait for '" << filename << "' timed out and took " << t;
return -1;
}
void ImportKernelCmdline(const std::function<void(const std::string&, const std::string&)>& fn) {
std::string cmdline;
android::base::ReadFileToString("/proc/cmdline", &cmdline);
for (const auto& entry : android::base::Split(android::base::Trim(cmdline), " ")) {
std::vector<std::string> pieces = android::base::Split(entry, "=");
if (pieces.size() == 2) {
fn(pieces[0], pieces[1]);
}
}
}
void ImportBootconfig(const std::function<void(const std::string&, const std::string&)>& fn) {
std::string bootconfig;
android::base::ReadFileToString("/proc/bootconfig", &bootconfig);
for (const auto& entry : android::base::Split(bootconfig, "\n")) {
std::vector<std::string> pieces = android::base::Split(entry, "=");
if (pieces.size() == 2) {
// get rid of the extra space between a list of values and remove the quotes.
std::string value = android::base::StringReplace(pieces[1], "\", \"", ",", true);
value.erase(std::remove(value.begin(), value.end(), '"'), value.end());
fn(android::base::Trim(pieces[0]), android::base::Trim(value));
}
}
}
bool make_dir(const std::string& path, mode_t mode) {
std::string secontext;
if (SelabelLookupFileContext(path, mode, &secontext) && !secontext.empty()) {
setfscreatecon(secontext.c_str());
}
int rc = mkdir(path.c_str(), mode);
if (!secontext.empty()) {
int save_errno = errno;
setfscreatecon(nullptr);
errno = save_errno;
}
return rc == 0;
}
/*
* Returns true is pathname is a directory
*/
bool is_dir(const char* pathname) {
struct stat info;
if (stat(pathname, &info) == -1) {
return false;
}
return S_ISDIR(info.st_mode);
}
Result<std::string> ExpandProps(const std::string& src) {
const char* src_ptr = src.c_str();
std::string dst;
/* - variables can either be $x.y or ${x.y}, in case they are only part
* of the string.
* - will accept $$ as a literal $.
* - no nested property expansion, i.e. ${foo.${bar}} is not supported,
* bad things will happen
* - ${x.y:-default} will return default value if property empty.
*/
while (*src_ptr) {
const char* c;
c = strchr(src_ptr, '$');
if (!c) {
dst.append(src_ptr);
return dst;
}
dst.append(src_ptr, c);
c++;
if (*c == '$') {
dst.push_back(*(c++));
src_ptr = c;
continue;
} else if (*c == '\0') {
return dst;
}
std::string prop_name;
std::string def_val;
if (*c == '{') {
c++;
const char* end = strchr(c, '}');
if (!end) {
// failed to find closing brace, abort.
return Error() << "unexpected end of string in '" << src << "', looking for }";
}
prop_name = std::string(c, end);
c = end + 1;
size_t def = prop_name.find(":-");
if (def < prop_name.size()) {
def_val = prop_name.substr(def + 2);
prop_name = prop_name.substr(0, def);
}
} else {
prop_name = c;
if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_R__) {
return Error() << "using deprecated syntax for specifying property '" << c
<< "', use ${name} instead";
} else {
LOG(ERROR) << "using deprecated syntax for specifying property '" << c
<< "', use ${name} instead";
}
c += prop_name.size();
}
if (prop_name.empty()) {
return Error() << "invalid zero-length property name in '" << src << "'";
}
std::string prop_val = android::base::GetProperty(prop_name, "");
if (prop_val.empty()) {
if (def_val.empty()) {
return Error() << "property '" << prop_name << "' doesn't exist while expanding '"
<< src << "'";
}
prop_val = def_val;
}
dst.append(prop_val);
src_ptr = c;
}
return dst;
}
static std::string init_android_dt_dir() {
// Use the standard procfs-based path by default
std::string android_dt_dir = kDefaultAndroidDtDir;
// The platform may specify a custom Android DT path in kernel cmdline
ImportKernelCmdline([&](const std::string& key, const std::string& value) {
if (key == "androidboot.android_dt_dir") {
android_dt_dir = value;
}
});
// ..Or bootconfig
if (android_dt_dir == kDefaultAndroidDtDir) {
ImportBootconfig([&](const std::string& key, const std::string& value) {
if (key == "androidboot.android_dt_dir") {
android_dt_dir = value;
}
});
}
LOG(INFO) << "Using Android DT directory " << android_dt_dir;
return android_dt_dir;
}
// FIXME: The same logic is duplicated in system/core/fs_mgr/
const std::string& get_android_dt_dir() {
// Set once and saves time for subsequent calls to this function
static const std::string kAndroidDtDir = init_android_dt_dir();
return kAndroidDtDir;
}
// Reads the content of device tree file under the platform's Android DT directory.
// Returns true if the read is success, false otherwise.
bool read_android_dt_file(const std::string& sub_path, std::string* dt_content) {
const std::string file_name = get_android_dt_dir() + sub_path;
if (android::base::ReadFileToString(file_name, dt_content)) {
if (!dt_content->empty()) {
dt_content->pop_back(); // Trims the trailing '\0' out.
return true;
}
}
return false;
}
bool is_android_dt_value_expected(const std::string& sub_path, const std::string& expected_content) {
std::string dt_content;
if (read_android_dt_file(sub_path, &dt_content)) {
if (dt_content == expected_content) {
return true;
}
}
return false;
}
bool IsLegalPropertyName(const std::string& name) {
size_t namelen = name.size();
if (namelen < 1) return false;
if (name[0] == '.') return false;
if (name[namelen - 1] == '.') return false;
/* Only allow alphanumeric, plus '.', '-', '@', ':', or '_' */
/* Don't allow ".." to appear in a property name */
for (size_t i = 0; i < namelen; i++) {
if (name[i] == '.') {
// i=0 is guaranteed to never have a dot. See above.
if (name[i - 1] == '.') return false;
continue;
}
if (name[i] == '_' || name[i] == '-' || name[i] == '@' || name[i] == ':') continue;
if (name[i] >= 'a' && name[i] <= 'z') continue;
if (name[i] >= 'A' && name[i] <= 'Z') continue;
if (name[i] >= '0' && name[i] <= '9') continue;
return false;
}
return true;
}
Result<void> IsLegalPropertyValue(const std::string& name, const std::string& value) {
if (value.size() >= PROP_VALUE_MAX && !StartsWith(name, "ro.")) {
return Error() << "Property value too long";
}
if (mbstowcs(nullptr, value.data(), 0) == static_cast<std::size_t>(-1)) {
return Error() << "Value is not a UTF8 encoded string";
}
return {};
}
static FscryptAction FscryptInferAction(const std::string& dir) {
const std::string prefix = "/data/";
if (!android::base::StartsWith(dir, prefix)) {
return FscryptAction::kNone;
}
// Special-case /data/media/obb per b/64566063
if (dir == "/data/media/obb") {
// Try to set policy on this directory, but if it is non-empty this may fail.
return FscryptAction::kAttempt;
}
// Only set policy on first level /data directories
// To make this less restrictive, consider using a policy file.
// However this is overkill for as long as the policy is simply
// to apply a global policy to all /data folders created via makedir
if (dir.find_first_of('/', prefix.size()) != std::string::npos) {
return FscryptAction::kNone;
}
// Special case various directories that must not be encrypted,
// often because their subdirectories must be encrypted.
// This isn't a nice way to do this, see b/26641735
std::vector<std::string> directories_to_exclude = {
"lost+found", "system_ce", "system_de", "misc_ce", "misc_de",
"vendor_ce", "vendor_de", "media", "data", "user",
"user_de", "apex", "preloads", "app-staging", "gsi",
};
for (const auto& d : directories_to_exclude) {
if ((prefix + d) == dir) {
return FscryptAction::kNone;
}
}
// Empty these directories if policy setting fails.
std::vector<std::string> wipe_on_failure = {
"rollback", "rollback-observer", // b/139193659
};
for (const auto& d : wipe_on_failure) {
if ((prefix + d) == dir) {
return FscryptAction::kDeleteIfNecessary;
}
}
return FscryptAction::kRequire;
}
Result<MkdirOptions> ParseMkdir(const std::vector<std::string>& args) {
mode_t mode = 0755;
Result<uid_t> uid = -1;
Result<gid_t> gid = -1;
FscryptAction fscrypt_inferred_action = FscryptInferAction(args[1]);
FscryptAction fscrypt_action = fscrypt_inferred_action;
std::string ref_option = "ref";
bool set_option_encryption = false;
bool set_option_key = false;
for (size_t i = 2; i < args.size(); i++) {
switch (i) {
case 2:
mode = std::strtoul(args[2].c_str(), 0, 8);
break;
case 3:
uid = DecodeUid(args[3]);
if (!uid.ok()) {
return Error()
<< "Unable to decode UID for '" << args[3] << "': " << uid.error();
}
break;
case 4:
gid = DecodeUid(args[4]);
if (!gid.ok()) {
return Error()
<< "Unable to decode GID for '" << args[4] << "': " << gid.error();
}
break;
default:
auto parts = android::base::Split(args[i], "=");
if (parts.size() != 2) {
return Error() << "Can't parse option: '" << args[i] << "'";
}
auto optname = parts[0];
auto optval = parts[1];
if (optname == "encryption") {
if (set_option_encryption) {
return Error() << "Duplicated option: '" << optname << "'";
}
if (optval == "Require") {
fscrypt_action = FscryptAction::kRequire;
} else if (optval == "None") {
fscrypt_action = FscryptAction::kNone;
} else if (optval == "Attempt") {
fscrypt_action = FscryptAction::kAttempt;
} else if (optval == "DeleteIfNecessary") {
fscrypt_action = FscryptAction::kDeleteIfNecessary;
} else {
return Error() << "Unknown encryption option: '" << optval << "'";
}
set_option_encryption = true;
} else if (optname == "key") {
if (set_option_key) {
return Error() << "Duplicated option: '" << optname << "'";
}
if (optval == "ref" || optval == "per_boot_ref") {
ref_option = optval;
} else {
return Error() << "Unknown key option: '" << optval << "'";
}
set_option_key = true;
} else {
return Error() << "Unknown option: '" << args[i] << "'";
}
}
}
if (set_option_key && fscrypt_action == FscryptAction::kNone) {
return Error() << "Key option set but encryption action is none";
}
const std::string prefix = "/data/";
if (StartsWith(args[1], prefix) &&
args[1].find_first_of('/', prefix.size()) == std::string::npos) {
if (!set_option_encryption) {
LOG(WARNING) << "Top-level directory needs encryption action, eg mkdir " << args[1]
<< " <mode> <uid> <gid> encryption=Require";
}
if (fscrypt_action == FscryptAction::kNone) {
LOG(INFO) << "Not setting encryption policy on: " << args[1];
}
}
if (fscrypt_action != fscrypt_inferred_action) {
LOG(WARNING) << "Inferred action different from explicit one, expected "
<< static_cast<int>(fscrypt_inferred_action) << " but got "
<< static_cast<int>(fscrypt_action);
}
return MkdirOptions{args[1], mode, *uid, *gid, fscrypt_action, ref_option};
}
Result<MountAllOptions> ParseMountAll(const std::vector<std::string>& args) {
bool compat_mode = false;
bool import_rc = false;
if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) {
if (args.size() <= 1) {
return Error() << "mount_all requires at least 1 argument";
}
compat_mode = true;
import_rc = true;
}
std::size_t first_option_arg = args.size();
enum mount_mode mode = MOUNT_MODE_DEFAULT;
// If we are <= Q, then stop looking for non-fstab arguments at slot 2.
// Otherwise, stop looking at slot 1 (as the fstab path argument is optional >= R).
for (std::size_t na = args.size() - 1; na > (compat_mode ? 1 : 0); --na) {
if (args[na] == "--early") {
first_option_arg = na;
mode = MOUNT_MODE_EARLY;
} else if (args[na] == "--late") {
first_option_arg = na;
mode = MOUNT_MODE_LATE;
import_rc = false;
}
}
std::string fstab_path;
if (first_option_arg > 1) {
fstab_path = args[1];
} else if (compat_mode) {
return Error() << "mount_all argument 1 must be the fstab path";
}
std::vector<std::string> rc_paths;
for (std::size_t na = 2; na < first_option_arg; ++na) {
rc_paths.push_back(args[na]);
}
return MountAllOptions{rc_paths, fstab_path, mode, import_rc};
}
Result<std::pair<int, std::vector<std::string>>> ParseRestorecon(
const std::vector<std::string>& args) {
struct flag_type {
const char* name;
int value;
};
static const flag_type flags[] = {
{"--recursive", SELINUX_ANDROID_RESTORECON_RECURSE},
{"--skip-ce", SELINUX_ANDROID_RESTORECON_SKIPCE},
{"--cross-filesystems", SELINUX_ANDROID_RESTORECON_CROSS_FILESYSTEMS},
{0, 0}};
int flag = 0;
std::vector<std::string> paths;
bool in_flags = true;
for (size_t i = 1; i < args.size(); ++i) {
if (android::base::StartsWith(args[i], "--")) {
if (!in_flags) {
return Error() << "flags must precede paths";
}
bool found = false;
for (size_t j = 0; flags[j].name; ++j) {
if (args[i] == flags[j].name) {
flag |= flags[j].value;
found = true;
break;
}
}
if (!found) {
return Error() << "bad flag " << args[i];
}
} else {
in_flags = false;
paths.emplace_back(args[i]);
}
}
return std::pair(flag, paths);
}
Result<std::string> ParseSwaponAll(const std::vector<std::string>& args) {
if (args.size() <= 1) {
if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) {
return Error() << "swapon_all requires at least 1 argument";
}
return {};
}
return args[1];
}
Result<std::string> ParseUmountAll(const std::vector<std::string>& args) {
if (args.size() <= 1) {
if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) {
return Error() << "umount_all requires at least 1 argument";
}
return {};
}
return args[1];
}
static void InitAborter(const char* abort_message) {
// When init forks, it continues to use this aborter for LOG(FATAL), but we want children to
// simply abort instead of trying to reboot the system.
if (getpid() != 1) {
android::base::DefaultAborter(abort_message);
return;
}
InitFatalReboot(SIGABRT);
}
// The kernel opens /dev/console and uses that fd for stdin/stdout/stderr if there is a serial
// console enabled and no initramfs, otherwise it does not provide any fds for stdin/stdout/stderr.
// SetStdioToDevNull() is used to close these existing fds if they exist and replace them with
// /dev/null regardless.
//
// In the case that these fds are provided by the kernel, the exec of second stage init causes an
// SELinux denial as it does not have access to /dev/console. In the case that they are not
// provided, exec of any further process is potentially dangerous as the first fd's opened by that
// process will take the stdin/stdout/stderr fileno's, which can cause issues if printf(), etc is
// then used by that process.
//
// Lastly, simply calling SetStdioToDevNull() in first stage init is not enough, since first
// stage init still runs in kernel context, future child processes will not have permissions to
// access any fds that it opens, including the one opened below for /dev/null. Therefore,
// SetStdioToDevNull() must be called again in second stage init.
void SetStdioToDevNull(char** argv) {
// Make stdin/stdout/stderr all point to /dev/null.
int fd = open("/dev/null", O_RDWR); // NOLINT(android-cloexec-open)
if (fd == -1) {
int saved_errno = errno;
android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter);
errno = saved_errno;
PLOG(FATAL) << "Couldn't open /dev/null";
}
dup2(fd, STDIN_FILENO);
dup2(fd, STDOUT_FILENO);
dup2(fd, STDERR_FILENO);
if (fd > STDERR_FILENO) close(fd);
}
void InitKernelLogging(char** argv) {
SetFatalRebootTarget();
android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter);
}
bool IsRecoveryMode() {
return access("/system/bin/recovery", F_OK) == 0;
}
// Check if default mount namespace is ready to be used with APEX modules
static bool is_default_mount_namespace_ready = false;
bool IsDefaultMountNamespaceReady() {
return is_default_mount_namespace_ready;
}
void SetDefaultMountNamespaceReady() {
is_default_mount_namespace_ready = true;
}
bool IsMicrodroid() {
static bool is_microdroid = android::base::GetProperty("ro.hardware", "") == "microdroid";
return is_microdroid;
}
} // namespace init
} // namespace android
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