diff --git a/libs/binder/UtilsHost.cpp b/libs/binder/UtilsHost.cpp
new file mode 100644
index 0000000..e524dab
--- /dev/null
+++ b/libs/binder/UtilsHost.cpp
@@ -0,0 +1,177 @@
+/*
+ * Copyright (C) 2021 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 "UtilsHost.h"
+
+#include <poll.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <sstream>
+
+#include <log/log.h>
+
+namespace android {
+
+CommandResult::~CommandResult() {
+    if (!pid.has_value()) return;
+    if (*pid == 0) {
+        ALOGW("%s: PID is unexpectedly 0, won't kill it", __PRETTY_FUNCTION__);
+        return;
+    }
+
+    ALOGE_IF(kill(*pid, SIGKILL) != 0, "kill(%d): %s", *pid, strerror(errno));
+
+    while (pid.has_value()) {
+        int status;
+        LOG_HOST("%s: Waiting for PID %d to exit.", __PRETTY_FUNCTION__, *pid);
+        int waitres = waitpid(*pid, &status, 0);
+        if (waitres == -1) {
+            ALOGE("%s: waitpid(%d): %s", __PRETTY_FUNCTION__, *pid, strerror(errno));
+            break;
+        }
+        if (WIFEXITED(status)) {
+            LOG_HOST("%s: PID %d exited.", __PRETTY_FUNCTION__, *pid);
+            pid.reset();
+        } else if (WIFSIGNALED(status)) {
+            LOG_HOST("%s: PID %d terminated by signal %d.", __PRETTY_FUNCTION__, *pid,
+                     WTERMSIG(status));
+            pid.reset();
+        } else if (WIFSTOPPED(status)) {
+            ALOGW("%s: pid %d stopped", __PRETTY_FUNCTION__, *pid);
+        } else if (WIFCONTINUED(status)) {
+            ALOGW("%s: pid %d continued", __PRETTY_FUNCTION__, *pid);
+        }
+    }
+}
+
+std::ostream& operator<<(std::ostream& os, const CommandResult& res) {
+    if (res.exitCode) os << "code=" << *res.exitCode;
+    if (res.signal) os << "signal=" << *res.signal;
+    if (res.pid) os << ", pid=" << *res.pid;
+    return os << ", stdout=" << res.stdout << ", stderr=" << res.stderr;
+}
+
+std::string CommandResult::toString() const {
+    std::stringstream ss;
+    ss << (*this);
+    return ss.str();
+}
+
+android::base::Result<CommandResult> execute(std::vector<std::string> argStringVec,
+                                             const std::function<bool(const CommandResult&)>& end) {
+    // turn vector<string> into null-terminated char* vector.
+    std::vector<char*> argv;
+    argv.reserve(argStringVec.size() + 1);
+    for (auto& arg : argStringVec) argv.push_back(arg.data());
+    argv.push_back(nullptr);
+
+    CommandResult ret;
+    android::base::unique_fd outWrite;
+    if (!android::base::Pipe(&ret.outPipe, &outWrite))
+        return android::base::ErrnoError() << "pipe() for outPipe";
+    android::base::unique_fd errWrite;
+    if (!android::base::Pipe(&ret.errPipe, &errWrite))
+        return android::base::ErrnoError() << "pipe() for errPipe";
+
+    int pid = fork();
+    if (pid == -1) return android::base::ErrnoError() << "fork()";
+    if (pid == 0) {
+        // child
+        ret.outPipe.reset();
+        ret.errPipe.reset();
+
+        int res = TEMP_FAILURE_RETRY(dup2(outWrite.get(), STDOUT_FILENO));
+        LOG_ALWAYS_FATAL_IF(-1 == res, "dup2(outPipe): %s", strerror(errno));
+        outWrite.reset();
+
+        res = TEMP_FAILURE_RETRY(dup2(errWrite.get(), STDERR_FILENO));
+        LOG_ALWAYS_FATAL_IF(-1 == res, "dup2(errPipe): %s", strerror(errno));
+        errWrite.reset();
+
+        execvp(argv[0], argv.data());
+        LOG_ALWAYS_FATAL("execvp() returns");
+    }
+    // parent
+    outWrite.reset();
+    errWrite.reset();
+    ret.pid = pid;
+
+    auto handlePoll = [](android::base::unique_fd* fd, const pollfd& pfd, std::string* s) {
+        if (!fd->ok()) return true;
+        if (pfd.revents & POLLIN) {
+            char buf[1024];
+            ssize_t n = TEMP_FAILURE_RETRY(read(fd->get(), buf, sizeof(buf)));
+            if (n < 0) return false;
+            if (n > 0) *s += std::string_view(buf, n);
+        }
+        if (pfd.revents & POLLHUP) {
+            fd->reset();
+        }
+        return true;
+    };
+
+    // Drain both stdout and stderr. Check end() regularly until both are closed.
+    while (ret.outPipe.ok() || ret.errPipe.ok()) {
+        pollfd fds[2];
+        pollfd *outPollFd = nullptr, *errPollFd = nullptr;
+        memset(fds, 0, sizeof(fds));
+        nfds_t nfds = 0;
+        if (ret.outPipe.ok()) {
+            outPollFd = &fds[nfds++];
+            *outPollFd = {.fd = ret.outPipe.get(), .events = POLLIN};
+        }
+        if (ret.errPipe.ok()) {
+            errPollFd = &fds[nfds++];
+            *errPollFd = {.fd = ret.errPipe.get(), .events = POLLIN};
+        }
+        int pollRet = poll(fds, nfds, 1000 /* ms timeout */);
+        if (pollRet == -1) return android::base::ErrnoError() << "poll()";
+
+        if (!handlePoll(&ret.outPipe, *outPollFd, &ret.stdout))
+            return android::base::ErrnoError() << "read(stdout)";
+        if (!handlePoll(&ret.errPipe, *errPollFd, &ret.stderr))
+            return android::base::ErrnoError() << "read(stderr)";
+
+        if (end && end(ret)) return ret;
+    }
+
+    // If both stdout and stderr are closed by the subprocess, it may or may not be terminated.
+    while (ret.pid.has_value()) {
+        int status;
+        auto exitPid = waitpid(pid, &status, 0);
+        if (exitPid == -1) return android::base::ErrnoError() << "waitpid(" << pid << ")";
+        if (exitPid == pid) {
+            if (WIFEXITED(status)) {
+                ret.pid = std::nullopt;
+                ret.exitCode = WEXITSTATUS(status);
+            } else if (WIFSIGNALED(status)) {
+                ret.pid = std::nullopt;
+                ret.signal = WTERMSIG(status);
+            } else if (WIFSTOPPED(status)) {
+                ALOGW("%s: pid %d stopped", __PRETTY_FUNCTION__, *ret.pid);
+            } else if (WIFCONTINUED(status)) {
+                ALOGW("%s: pid %d continued", __PRETTY_FUNCTION__, *ret.pid);
+            }
+        }
+        // ret is not changed unless the process is terminated (where pid == nullopt). Hence there
+        // is no need to check the predicate `end(ret)`.
+    }
+
+    return ret;
+}
+} // namespace android