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/*
* 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 "firmware_handler.h"
#include <fcntl.h>
#include <fnmatch.h>
#include <glob.h>
#include <pwd.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sendfile.h>
#include <sys/wait.h>
#include <unistd.h>
#include <thread>
#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/scopeguard.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
using android::base::ReadFdToString;
using android::base::Socketpair;
using android::base::Split;
using android::base::Timer;
using android::base::Trim;
using android::base::unique_fd;
using android::base::WriteFully;
namespace android {
namespace init {
namespace {
bool PrefixMatch(const std::string& pattern, const std::string& path) {
return android::base::StartsWith(path, pattern);
}
bool FnMatch(const std::string& pattern, const std::string& path) {
return fnmatch(pattern.c_str(), path.c_str(), 0) == 0;
}
bool EqualMatch(const std::string& pattern, const std::string& path) {
return pattern == path;
}
} // namespace
static void LoadFirmware(const std::string& firmware, const std::string& root, int fw_fd,
size_t fw_size, int loading_fd, int data_fd) {
// Start transfer.
WriteFully(loading_fd, "1", 1);
// Copy the firmware.
int rc = sendfile(data_fd, fw_fd, nullptr, fw_size);
if (rc == -1) {
PLOG(ERROR) << "firmware: sendfile failed { '" << root << "', '" << firmware << "' }";
}
// Tell the firmware whether to abort or commit.
const char* response = (rc != -1) ? "0" : "-1";
WriteFully(loading_fd, response, strlen(response));
}
static bool IsBooting() {
return access("/dev/.booting", F_OK) == 0;
}
ExternalFirmwareHandler::ExternalFirmwareHandler(std::string devpath, uid_t uid,
std::string handler_path)
: devpath(std::move(devpath)), uid(uid), handler_path(std::move(handler_path)) {
auto wildcard_position = this->devpath.find('*');
if (wildcard_position != std::string::npos) {
if (wildcard_position == this->devpath.length() - 1) {
this->devpath.pop_back();
match = std::bind(PrefixMatch, this->devpath, std::placeholders::_1);
} else {
match = std::bind(FnMatch, this->devpath, std::placeholders::_1);
}
} else {
match = std::bind(EqualMatch, this->devpath, std::placeholders::_1);
}
}
FirmwareHandler::FirmwareHandler(std::vector<std::string> firmware_directories,
std::vector<ExternalFirmwareHandler> external_firmware_handlers)
: firmware_directories_(std::move(firmware_directories)),
external_firmware_handlers_(std::move(external_firmware_handlers)) {}
Result<std::string> FirmwareHandler::RunExternalHandler(const std::string& handler, uid_t uid,
const Uevent& uevent) const {
unique_fd child_stdout;
unique_fd parent_stdout;
if (!Socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, &child_stdout, &parent_stdout)) {
return ErrnoError() << "Socketpair() for stdout failed";
}
unique_fd child_stderr;
unique_fd parent_stderr;
if (!Socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, &child_stderr, &parent_stderr)) {
return ErrnoError() << "Socketpair() for stderr failed";
}
signal(SIGCHLD, SIG_DFL);
auto pid = fork();
if (pid < 0) {
return ErrnoError() << "fork() failed";
}
if (pid == 0) {
setenv("FIRMWARE", uevent.firmware.c_str(), 1);
setenv("DEVPATH", uevent.path.c_str(), 1);
parent_stdout.reset();
parent_stderr.reset();
close(STDOUT_FILENO);
close(STDERR_FILENO);
dup2(child_stdout.get(), STDOUT_FILENO);
dup2(child_stderr.get(), STDERR_FILENO);
auto args = Split(handler, " ");
std::vector<char*> c_args;
for (auto& arg : args) {
c_args.emplace_back(arg.data());
}
c_args.emplace_back(nullptr);
if (setuid(uid) != 0) {
fprintf(stderr, "setuid() failed: %s", strerror(errno));
_exit(EXIT_FAILURE);
}
execv(c_args[0], c_args.data());
fprintf(stderr, "exec() failed: %s", strerror(errno));
_exit(EXIT_FAILURE);
}
child_stdout.reset();
child_stderr.reset();
int status;
pid_t waited_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
if (waited_pid == -1) {
return ErrnoError() << "waitpid() failed";
}
std::string stdout_content;
if (!ReadFdToString(parent_stdout.get(), &stdout_content)) {
return ErrnoError() << "ReadFdToString() for stdout failed";
}
std::string stderr_content;
if (ReadFdToString(parent_stderr.get(), &stderr_content)) {
auto messages = Split(stderr_content, "\n");
for (const auto& message : messages) {
if (!message.empty()) {
LOG(ERROR) << "External Firmware Handler: " << message;
}
}
} else {
LOG(ERROR) << "ReadFdToString() for stderr failed";
}
if (WIFEXITED(status)) {
if (WEXITSTATUS(status) == EXIT_SUCCESS) {
return Trim(stdout_content);
} else {
return Error() << "exited with status " << WEXITSTATUS(status);
}
} else if (WIFSIGNALED(status)) {
return Error() << "killed by signal " << WTERMSIG(status);
}
return Error() << "unexpected exit status " << status;
}
std::string FirmwareHandler::GetFirmwarePath(const Uevent& uevent) const {
for (const auto& external_handler : external_firmware_handlers_) {
if (external_handler.match(uevent.path)) {
LOG(INFO) << "Launching external firmware handler '" << external_handler.handler_path
<< "' for devpath: '" << uevent.path << "' firmware: '" << uevent.firmware
<< "'";
auto result =
RunExternalHandler(external_handler.handler_path, external_handler.uid, uevent);
if (!result.ok()) {
LOG(ERROR) << "Using default firmware; External firmware handler failed: "
<< result.error();
return uevent.firmware;
}
if (result->find("..") != std::string::npos) {
LOG(ERROR) << "Using default firmware; External firmware handler provided an "
"invalid path, '"
<< *result << "'";
return uevent.firmware;
}
LOG(INFO) << "Loading firmware '" << *result << "' in place of '" << uevent.firmware
<< "'";
return *result;
}
}
LOG(INFO) << "firmware: loading '" << uevent.firmware << "' for '" << uevent.path << "'";
return uevent.firmware;
}
void FirmwareHandler::ProcessFirmwareEvent(const std::string& root,
const std::string& firmware) const {
std::string loading = root + "/loading";
std::string data = root + "/data";
unique_fd loading_fd(open(loading.c_str(), O_WRONLY | O_CLOEXEC));
if (loading_fd == -1) {
PLOG(ERROR) << "couldn't open firmware loading fd for " << firmware;
return;
}
unique_fd data_fd(open(data.c_str(), O_WRONLY | O_CLOEXEC));
if (data_fd == -1) {
PLOG(ERROR) << "couldn't open firmware data fd for " << firmware;
return;
}
std::vector<std::string> attempted_paths_and_errors;
auto TryLoadFirmware = [&](const std::string& firmware_directory) {
std::string file = firmware_directory + firmware;
unique_fd fw_fd(open(file.c_str(), O_RDONLY | O_CLOEXEC));
if (fw_fd == -1) {
attempted_paths_and_errors.emplace_back("firmware: attempted " + file +
", open failed: " + strerror(errno));
return false;
}
struct stat sb;
if (fstat(fw_fd, &sb) == -1) {
attempted_paths_and_errors.emplace_back("firmware: attempted " + file +
", fstat failed: " + strerror(errno));
return false;
}
LoadFirmware(firmware, root, fw_fd, sb.st_size, loading_fd, data_fd);
return true;
};
int booting = IsBooting();
try_loading_again:
attempted_paths_and_errors.clear();
if (ForEachFirmwareDirectory(TryLoadFirmware)) {
return;
}
if (booting) {
// If we're not fully booted, we may be missing
// filesystems needed for firmware, wait and retry.
std::this_thread::sleep_for(100ms);
booting = IsBooting();
goto try_loading_again;
}
LOG(ERROR) << "firmware: could not find firmware for " << firmware;
for (const auto& message : attempted_paths_and_errors) {
LOG(ERROR) << message;
}
// Write "-1" as our response to the kernel's firmware request, since we have nothing for it.
write(loading_fd, "-1", 2);
}
bool FirmwareHandler::ForEachFirmwareDirectory(
std::function<bool(const std::string&)> handler) const {
for (const std::string& firmware_directory : firmware_directories_) {
if (std::invoke(handler, firmware_directory)) {
return true;
}
}
glob_t glob_result;
glob("/apex/*/etc/firmware/", GLOB_MARK, nullptr, &glob_result);
auto free_glob = android::base::make_scope_guard(std::bind(&globfree, &glob_result));
for (size_t i = 0; i < glob_result.gl_pathc; i++) {
char* apex_firmware_directory = glob_result.gl_pathv[i];
// Filter-out /apex/<name>@<ver> paths. The paths are bind-mounted to
// /apex/<name> paths, so unless we filter them out, we will look into the
// same apex twice.
if (strchr(apex_firmware_directory, '@')) {
continue;
}
if (std::invoke(handler, apex_firmware_directory)) {
return true;
}
}
return false;
}
void FirmwareHandler::HandleUevent(const Uevent& uevent) {
if (uevent.subsystem != "firmware" || uevent.action != "add") return;
// Loading the firmware in a child means we can do that in parallel...
auto pid = fork();
if (pid == -1) {
PLOG(ERROR) << "could not fork to process firmware event for " << uevent.firmware;
}
if (pid == 0) {
Timer t;
auto firmware = GetFirmwarePath(uevent);
ProcessFirmwareEvent("/sys" + uevent.path, firmware);
LOG(INFO) << "loading " << uevent.path << " took " << t;
_exit(EXIT_SUCCESS);
}
}
} // namespace init
} // namespace android