firmware_handler: extract part responsible for running ext program to lib
As a preparation for upcoming commit, extract part which is responsible
for external program execution to libmodprobe so it can be later
re-used not only for firmware handler but also for dynamic module
options handler within libmodprobe.
RunExternalHandler is moved entirely to separate library with two
changes:
- Setting env needed previously by firmware handler was made generic and
now external handler can get envs_map containing pairs of env and its
value which needs to be set.
- "Firmware" was removed from one of the log since now it can be used in
different context (s/External Firmware Handler/External Handler/)
Bug: 335619610
Test: `atest CtsInitTestCases` passed, especially:
[105/129] ueventd_parser#ExternalFirmwareHandlers: PASSED (0ms)
[106/129] ueventd_parser#ExternalFirmwareHandlersDuplicate: PASSED (0ms)
Change-Id: Ie07cee763278f224bd3c0acfbe06c44eb36d0a81
diff --git a/libmodprobe/Android.bp b/libmodprobe/Android.bp
index 12906cc..78b4c83 100644
--- a/libmodprobe/Android.bp
+++ b/libmodprobe/Android.bp
@@ -13,6 +13,7 @@
vendor_ramdisk_available: true,
host_supported: true,
srcs: [
+ "exthandler.cpp",
"libmodprobe.cpp",
"libmodprobe_ext.cpp",
],
@@ -30,6 +31,7 @@
],
local_include_dirs: ["include/"],
srcs: [
+ "exthandler.cpp",
"libmodprobe_test.cpp",
"libmodprobe.cpp",
"libmodprobe_ext_test.cpp",
diff --git a/libmodprobe/exthandler.cpp b/libmodprobe/exthandler.cpp
new file mode 100644
index 0000000..f48c259
--- /dev/null
+++ b/libmodprobe/exthandler.cpp
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2024 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 <exthandler/exthandler.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/strings.h>
+#include <android-base/unique_fd.h>
+#include <fnmatch.h>
+#include <grp.h>
+#include <pwd.h>
+#include <sys/wait.h>
+
+using android::base::ErrnoError;
+using android::base::Error;
+using android::base::ReadFdToString;
+using android::base::Result;
+using android::base::Split;
+using android::base::Trim;
+using android::base::unique_fd;
+
+Result<std::string> RunExternalHandler(const std::string& handler, uid_t uid, gid_t gid,
+ std::unordered_map<std::string, std::string>& envs_map) {
+ 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) {
+ for (auto it = envs_map.begin(); it != envs_map.end(); ++it) {
+ setenv(it->first.c_str(), it->second.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 (gid != 0) {
+ if (setgid(gid) != 0) {
+ fprintf(stderr, "setgid() failed: %s", strerror(errno));
+ _exit(EXIT_FAILURE);
+ }
+ }
+
+ 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 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;
+}
diff --git a/libmodprobe/include/exthandler/exthandler.h b/libmodprobe/include/exthandler/exthandler.h
new file mode 100644
index 0000000..232aa95
--- /dev/null
+++ b/libmodprobe/include/exthandler/exthandler.h
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2024 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.
+ */
+
+#pragma once
+#include <android-base/result.h>
+#include <string>
+
+android::base::Result<std::string> RunExternalHandler(
+ const std::string& handler, uid_t uid, gid_t gid,
+ std::unordered_map<std::string, std::string>& envs_map);