process: add execve

PR-URL: #56496
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Bryan English <bryan@bryanenglish.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: ShogunPanda

doc/api/diagnostics_channel.md

@@ -1319,6 +1319,14 @@ added: v16.18.0
 
 Emitted when a new process is created.
 
+`execve`
+
+* `execPath` {string}
+* `args` {string\[]}
+* `env` {string\[]}
+
+Emitted when [`process.execve()`][] is invoked.
+
 #### Worker Thread
 
 <!-- YAML
@@ -1348,5 +1356,6 @@ Emitted when a new thread is created.
 [`end` event]: #endevent
 [`error` event]: #errorevent
 [`net.Server.listen()`]: net.md#serverlisten
+[`process.execve()`]: process.md#processexecvefile-args-env
 [`start` event]: #startevent
 [context loss]: async_context.md#troubleshooting-context-loss

doc/api/process.md

@@ -2519,8 +2519,7 @@ if (process.getuid) {
 }
 ```
 
-This function is only available on POSIX platforms (i.e. not Windows or
-Android).
+This function not available on Windows.
 
 ## `process.hasUncaughtExceptionCaptureCallback()`
 
@@ -3346,6 +3345,33 @@ In custom builds from non-release versions of the source tree, only the
 `name` property may be present. The additional properties should not be
 relied upon to exist.
 
+## `process.execve(file[, args[, env]])`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+> Stability: 1 - Experimental
+
+* `file` {string} The name or path of the executable file to run.
+* `args` {string\[]} List of string arguments. No argument can contain a null-byte (`\u0000`).
+* `env` {Object} Environment key-value pairs.
+  No key or value can contain a null-byte (`\u0000`).
+  **Default:** `process.env`.
+
+Replaces the current process with a new process.
+
+This is achieved by using the `execve` POSIX function and therefore no memory or other
+resources from the current process are preserved, except for the standard input,
+standard output and standard error file descriptor.
+
+All other resources are discarded by the system when the processes are swapped, without triggering
+any exit or close events and without running any cleanup handler.
+
+This function will never return, unless an error occurred.
+
+This function is only available on POSIX platforms (i.e. not Windows or Android).
+
 ## `process.report`
 
 <!-- YAML

lib/internal/bootstrap/node.js

@@ -177,6 +177,7 @@ const rawMethods = internalBinding('process_methods');
   process.availableMemory = rawMethods.availableMemory;
   process.kill = wrapped.kill;
   process.exit = wrapped.exit;
+  process.execve = wrapped.execve;
   process.ref = perThreadSetup.ref;
   process.unref = perThreadSetup.unref;
 

lib/internal/process/per_thread.js

@@ -16,6 +16,7 @@ const {
   FunctionPrototypeCall,
   NumberMAX_SAFE_INTEGER,
   ObjectDefineProperty,
+  ObjectEntries,
   ObjectFreeze,
   ReflectApply,
   RegExpPrototypeExec,
@@ -24,6 +25,7 @@ const {
   SetPrototypeEntries,
   SetPrototypeValues,
   StringPrototypeEndsWith,
+  StringPrototypeIncludes,
   StringPrototypeReplace,
   StringPrototypeSlice,
   Symbol,
@@ -34,20 +36,27 @@ const {
 const {
   ErrnoException,
   codes: {
+    ERR_FEATURE_UNAVAILABLE_ON_PLATFORM,
     ERR_INVALID_ARG_TYPE,
     ERR_INVALID_ARG_VALUE,
     ERR_OPERATION_FAILED,
     ERR_OUT_OF_RANGE,
     ERR_UNKNOWN_SIGNAL,
+    ERR_WORKER_UNSUPPORTED_OPERATION,
   },
 } = require('internal/errors');
+const { emitExperimentalWarning } = require('internal/util');
 const format = require('internal/util/inspect').format;
 const {
   validateArray,
   validateNumber,
   validateObject,
+  validateString,
 } = require('internal/validators');
 
+const dc = require('diagnostics_channel');
+const execveDiagnosticChannel = dc.channel('process.execve');
+
 const constants = internalBinding('constants').os.signals;
 
 let getValidatedPath; // We need to lazy load it because of the circular dependency.
@@ -103,6 +112,7 @@ function wrapProcessMethods(binding) {
     rss,
     resourceUsage: _resourceUsage,
     loadEnvFile: _loadEnvFile,
+    execve: _execve,
   } = binding;
 
   function _rawDebug(...args) {
@@ -269,6 +279,55 @@ function wrapProcessMethods(binding) {
     return true;
   }
 
+  function execve(execPath, args, env) {
+    emitExperimentalWarning('process.execve');
+
+    const { isMainThread } = require('internal/worker');
+
+    if (!isMainThread) {
+      throw new ERR_WORKER_UNSUPPORTED_OPERATION('Calling process.execve');
+    } else if (process.platform === 'win32') {
+      throw new ERR_FEATURE_UNAVAILABLE_ON_PLATFORM('process.execve');
+    }
+
+    validateString(execPath, 'execPath');
+    validateArray(args, 'args');
+
+    for (let i = 0; i < args.length; i++) {
+      const arg = args[i];
+      if (typeof arg !== 'string' || StringPrototypeIncludes(arg, '\u0000')) {
+        throw new ERR_INVALID_ARG_VALUE(`args[${i}]`, arg, 'must be a string without null bytes');
+      }
+    }
+
+    const envArray = [];
+    if (env !== undefined) {
+      validateObject(env, 'env');
+
+      for (const { 0: key, 1: value } of ObjectEntries(env)) {
+        if (
+          typeof key !== 'string' ||
+          typeof value !== 'string' ||
+          StringPrototypeIncludes(key, '\u0000') ||
+          StringPrototypeIncludes(value, '\u0000')
+        ) {
+          throw new ERR_INVALID_ARG_VALUE(
+            'env', env, 'must be an object with string keys and values without null bytes',
+          );
+        } else {
+          ArrayPrototypePush(envArray, `${key}=${value}`);
+        }
+      }
+    }
+
+    if (execveDiagnosticChannel.hasSubscribers) {
+      execveDiagnosticChannel.publish({ execPath, args, env: envArray });
+    }
+
+    // Perform the system call
+    _execve(execPath, args, envArray);
+  }
+
   const resourceValues = new Float64Array(16);
   function resourceUsage() {
     _resourceUsage(resourceValues);
@@ -314,6 +373,7 @@ function wrapProcessMethods(binding) {
     memoryUsage,
     kill,
     exit,
+    execve,
     loadEnvFile,
   };
 }

src/node_errors.h

@@ -13,6 +13,11 @@
 #include <sstream>
 
 namespace node {
+// This forward declaration is required to have the method
+// available in error messages.
+namespace errors {
+const char* errno_string(int errorno);
+}
 
 enum ErrorHandlingMode { CONTEXTIFY_ERROR, FATAL_ERROR, MODULE_ERROR };
 void AppendExceptionLine(Environment* env,

src/node_process_methods.cc

@@ -27,12 +27,14 @@
 #if defined(_MSC_VER)
 #include <direct.h>
 #include <io.h>
+#include <process.h>
 #define umask _umask
 typedef int mode_t;
 #else
 #include <pthread.h>
 #include <sys/resource.h>  // getrlimit, setrlimit
 #include <termios.h>  // tcgetattr, tcsetattr
+#include <unistd.h>
 #endif
 
 namespace node {
@@ -495,6 +497,95 @@ static void ReallyExit(const FunctionCallbackInfo<Value>& args) {
   env->Exit(code);
 }
 
+#ifdef __POSIX__
+inline int persist_standard_stream(int fd) {
+  int flags = fcntl(fd, F_GETFD, 0);
+
+  if (flags < 0) {
+    return flags;
+  }
+
+  flags &= ~FD_CLOEXEC;
+  return fcntl(fd, F_SETFD, flags);
+}
+
+static void Execve(const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+  Isolate* isolate = env->isolate();
+  Local<Context> context = env->context();
+
+  THROW_IF_INSUFFICIENT_PERMISSIONS(
+      env, permission::PermissionScope::kChildProcess, "");
+
+  CHECK(args[0]->IsString());
+  CHECK(args[1]->IsArray());
+  CHECK(args[2]->IsArray());
+
+  Local<Array> argv_array = args[1].As<Array>();
+  Local<Array> envp_array = args[2].As<Array>();
+
+  // Copy arguments and environment
+  Utf8Value executable(isolate, args[0]);
+  std::vector<std::string> argv_strings(argv_array->Length());
+  std::vector<std::string> envp_strings(envp_array->Length());
+  std::vector<char*> argv(argv_array->Length() + 1);
+  std::vector<char*> envp(envp_array->Length() + 1);
+
+  for (unsigned int i = 0; i < argv_array->Length(); i++) {
+    Local<Value> str;
+    if (!argv_array->Get(context, i).ToLocal(&str)) {
+      THROW_ERR_INVALID_ARG_VALUE(env, "Failed to deserialize argument.");
+      return;
+    }
+
+    argv_strings[i] = Utf8Value(isolate, str).ToString();
+    argv[i] = argv_strings[i].data();
+  }
+  argv[argv_array->Length()] = nullptr;
+
+  for (unsigned int i = 0; i < envp_array->Length(); i++) {
+    Local<Value> str;
+    if (!envp_array->Get(context, i).ToLocal(&str)) {
+      THROW_ERR_INVALID_ARG_VALUE(
+          env, "Failed to deserialize environment variable.");
+      return;
+    }
+
+    envp_strings[i] = Utf8Value(isolate, str).ToString();
+    envp[i] = envp_strings[i].data();
+  }
+
+  envp[envp_array->Length()] = nullptr;
+
+  // Set stdin, stdout and stderr to be non-close-on-exec
+  // so that the new process will inherit it.
+  if (persist_standard_stream(0) < 0 || persist_standard_stream(1) < 0 ||
+      persist_standard_stream(2) < 0) {
+    env->ThrowErrnoException(errno, "fcntl");
+    return;
+  }
+
+  // Perform the execve operation.
+  RunAtExit(env);
+  execve(*executable, argv.data(), envp.data());
+
+  // If it returns, it means that the execve operation failed.
+  // In that case we abort the process.
+  auto error_message = std::string("process.execve failed with error code ") +
+                       errors::errno_string(errno);
+
+  // Abort the process
+  Local<v8::Value> exception =
+      ErrnoException(isolate, errno, "execve", *executable);
+  Local<v8::Message> message = v8::Exception::CreateMessage(isolate, exception);
+
+  std::string info = FormatErrorMessage(
+      isolate, context, error_message.c_str(), message, true);
+  FPrintF(stderr, "%s\n", info);
+  ABORT();
+}
+#endif
+
 static void LoadEnvFile(const v8::FunctionCallbackInfo<v8::Value>& args) {
   Environment* env = Environment::GetCurrent(args);
   std::string path = ".env";
@@ -687,6 +778,10 @@ static void CreatePerIsolateProperties(IsolateData* isolate_data,
   SetMethodNoSideEffect(isolate, target, "cwd", Cwd);
   SetMethod(isolate, target, "dlopen", binding::DLOpen);
   SetMethod(isolate, target, "reallyExit", ReallyExit);
+
+#ifdef __POSIX__
+  SetMethod(isolate, target, "execve", Execve);
+#endif
   SetMethodNoSideEffect(isolate, target, "uptime", Uptime);
   SetMethod(isolate, target, "patchProcessObject", PatchProcessObject);
 
@@ -730,6 +825,10 @@ void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
   registry->Register(Cwd);
   registry->Register(binding::DLOpen);
   registry->Register(ReallyExit);
+
+#ifdef __POSIX__
+  registry->Register(Execve);
+#endif
   registry->Register(Uptime);
   registry->Register(PatchProcessObject);
 

test/parallel/test-process-execve-abort.js

@@ -0,0 +1,26 @@
+'use strict';
+
+const { skip, isWindows } = require('../common');
+const { ok } = require('assert');
+const { spawnSync } = require('child_process');
+const { isMainThread } = require('worker_threads');
+
+if (!isMainThread) {
+  skip('process.execve is not available in Workers');
+} else if (isWindows) {
+  skip('process.execve is not available in Windows');
+}
+
+if (process.argv[2] === 'child') {
+  process.execve(
+    process.execPath + '_non_existing',
+    [__filename, 'replaced'],
+    { ...process.env, EXECVE_A: 'FIRST', EXECVE_B: 'SECOND', CWD: process.cwd() }
+  );
+} else {
+  const child = spawnSync(`${process.execPath}`, [`${__filename}`, 'child']);
+  const stderr = child.stderr.toString();
+
+  ok(stderr.includes('process.execve failed with error code ENOENT'), stderr);
+  ok(stderr.includes('execve (node:internal/process/per_thread'), stderr);
+}

test/parallel/test-process-execve-on-exit.js

@@ -0,0 +1,18 @@
+'use strict';
+
+const { mustNotCall, skip, isWindows } = require('../common');
+const { strictEqual } = require('assert');
+const { isMainThread } = require('worker_threads');
+
+if (!isMainThread) {
+  skip('process.execve is not available in Workers');
+} else if (isWindows) {
+  skip('process.execve is not available in Windows');
+}
+
+if (process.argv[2] === 'replaced') {
+  strictEqual(process.argv[2], 'replaced');
+} else {
+  process.on('exit', mustNotCall());
+  process.execve(process.execPath, [process.execPath, __filename, 'replaced'], process.env);
+}