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);