From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Darshan Sen <raisinten@gmail.com>
Date: Fri, 17 Jun 2022 13:19:32 +0530
Subject: posix: Replace DoubleForkAndExec() with ForkAndSpawn()

The DoubleForkAndExec() function was taking over 622 milliseconds to run
on macOS 11 (BigSur) on Intel i5-1038NG7. I did some debugging by adding
some custom traces and found that the fork() syscall is the bottleneck
here, i.e., the first fork() takes around 359 milliseconds and the
nested fork() takes around 263 milliseconds. Replacing the nested fork()
and exec() with posix_spawn() reduces the time consumption to 257
milliseconds!

See https://github.com/libuv/libuv/pull/3064 to know why fork() is so
slow on macOS and why posix_spawn() is a better replacement.

Another point to note is that even base::LaunchProcess() from Chromium
calls posix_spawnp() on macOS -
https://source.chromium.org/chromium/chromium/src/+/8f8d82dea0fa8f11f57c74dbb65126f8daba58f7:base/process/launch_mac.cc;l=295-296

Change-Id: I25c6ee9629a1ae5d0c32b361b56a1ce0b4b0fd26
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/3641386
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Mark Mentovai <mark@chromium.org>

diff --git a/third_party/crashpad/crashpad/AUTHORS b/third_party/crashpad/crashpad/AUTHORS
index 8dcac3238870920d374b86033d05d77ebde351e9..02103924332eddbd158c04f8a395bb4a247e8bd9 100644
--- a/third_party/crashpad/crashpad/AUTHORS
+++ b/third_party/crashpad/crashpad/AUTHORS
@@ -12,3 +12,4 @@ Opera Software ASA
 Vewd Software AS
 LG Electronics, Inc.
 MIPS Technologies, Inc.
+Darshan Sen <raisinten@gmail.com>
diff --git a/third_party/crashpad/crashpad/client/crashpad_client_linux.cc b/third_party/crashpad/crashpad/client/crashpad_client_linux.cc
index 295ec1615d83984835e238e349029b8755611f52..94c1cb02efe328ab45bc30fc7db8992872ed6b08 100644
--- a/third_party/crashpad/crashpad/client/crashpad_client_linux.cc
+++ b/third_party/crashpad/crashpad/client/crashpad_client_linux.cc
@@ -45,7 +45,7 @@
 #include "util/linux/socket.h"
 #include "util/misc/address_sanitizer.h"
 #include "util/misc/from_pointer_cast.h"
-#include "util/posix/double_fork_and_exec.h"
+#include "util/posix/fork_and_spawn.h"
 #include "util/posix/scoped_mmap.h"
 #include "util/posix/signals.h"
 
@@ -459,7 +459,7 @@ bool CrashpadClient::StartHandler(
 
   argv.push_back(FormatArgumentInt("initial-client-fd", handler_sock.get()));
   argv.push_back("--shared-client-connection");
-  if (!DoubleForkAndExec(argv, nullptr, handler_sock.get(), false, nullptr)) {
+  if (!ForkAndSpawn(argv, nullptr, handler_sock.get(), false, nullptr)) {
     return false;
   }
 
@@ -614,7 +614,7 @@ bool CrashpadClient::StartJavaHandlerForClient(
     int socket) {
   std::vector<std::string> argv = BuildAppProcessArgs(
       class_name, database, metrics_dir, url, annotations, arguments, socket);
-  return DoubleForkAndExec(argv, env, socket, false, nullptr);
+  return ForkAndSpawn(argv, env, socket, false, nullptr);
 }
 
 bool CrashpadClient::StartHandlerWithLinkerAtCrash(
@@ -663,7 +663,7 @@ bool CrashpadClient::StartHandlerWithLinkerForClient(
                                   annotations,
                                   arguments,
                                   socket);
-  return DoubleForkAndExec(argv, env, socket, false, nullptr);
+  return ForkAndSpawn(argv, env, socket, false, nullptr);
 }
 
 #endif
@@ -697,7 +697,7 @@ bool CrashpadClient::StartHandlerForClient(
 
   argv.push_back(FormatArgumentInt("initial-client-fd", socket));
 
-  return DoubleForkAndExec(argv, nullptr, socket, true, nullptr);
+  return ForkAndSpawn(argv, nullptr, socket, true, nullptr);
 }
 
 // static
diff --git a/third_party/crashpad/crashpad/client/crashpad_client_mac.cc b/third_party/crashpad/crashpad/client/crashpad_client_mac.cc
index 39e35678ecdd036f8c8ae27c973c27102b77da96..84385f2569f2bd00ca8aed0aa332fb450b2de1d3 100644
--- a/third_party/crashpad/crashpad/client/crashpad_client_mac.cc
+++ b/third_party/crashpad/crashpad/client/crashpad_client_mac.cc
@@ -36,7 +36,7 @@
 #include "util/mach/notify_server.h"
 #include "util/misc/clock.h"
 #include "util/misc/implicit_cast.h"
-#include "util/posix/double_fork_and_exec.h"
+#include "util/posix/fork_and_spawn.h"
 
 namespace crashpad {
 
@@ -343,7 +343,7 @@ class HandlerStarter final : public NotifyServer::DefaultInterface {
     // this parent process, which was probably using the exception server now
     // being restarted. The handler can’t monitor itself for its own crashes via
     // this interface.
-    if (!DoubleForkAndExec(
+    if (!ForkAndSpawn(
             argv,
             nullptr,
             server_write_fd.get(),
diff --git a/third_party/crashpad/crashpad/handler/linux/cros_crash_report_exception_handler.cc b/third_party/crashpad/crashpad/handler/linux/cros_crash_report_exception_handler.cc
index 9e58d94aa499fdb7271a78ea21a1dcc1b12e3a52..3caa3b987b35be575558a312026cf6f19485c418 100644
--- a/third_party/crashpad/crashpad/handler/linux/cros_crash_report_exception_handler.cc
+++ b/third_party/crashpad/crashpad/handler/linux/cros_crash_report_exception_handler.cc
@@ -29,7 +29,7 @@
 #include "util/linux/ptrace_client.h"
 #include "util/misc/metrics.h"
 #include "util/misc/uuid.h"
-#include "util/posix/double_fork_and_exec.h"
+#include "util/posix/fork_and_spawn.h"
 
 namespace crashpad {
 
@@ -266,12 +266,11 @@ bool CrosCrashReportExceptionHandler::HandleExceptionWithConnection(
     argv.push_back("--always_allow_feedback");
   }
 
-  if (!DoubleForkAndExec(argv,
-                         nullptr /* envp */,
-                         file_writer.fd() /* preserve_fd */,
-                         false /* use_path */,
-                         nullptr /* child_function */)) {
-    LOG(ERROR) << "DoubleForkAndExec failed";
+  if (!ForkAndSpawn(argv,
+                    nullptr /* envp */,
+                    file_writer.fd() /* preserve_fd */,
+                    false /* use_path */,
+                    nullptr /* child_function */)) {
     Metrics::ExceptionCaptureResult(
         Metrics::CaptureResult::kFinishedWritingCrashReportFailed);
     return false;
diff --git a/third_party/crashpad/crashpad/util/BUILD.gn b/third_party/crashpad/crashpad/util/BUILD.gn
index 30f03b13f3a018e6a96b0689452a344992675c23..64fa2e9e89b700d8a265a9737cb6a30a210cdffe 100644
--- a/third_party/crashpad/crashpad/util/BUILD.gn
+++ b/third_party/crashpad/crashpad/util/BUILD.gn
@@ -296,10 +296,10 @@ crashpad_static_library("util") {
       sources += [
         "posix/close_multiple.cc",
         "posix/close_multiple.h",
-        "posix/double_fork_and_exec.cc",
-        "posix/double_fork_and_exec.h",
         "posix/drop_privileges.cc",
         "posix/drop_privileges.h",
+        "posix/fork_and_spawn.cc",
+        "posix/fork_and_spawn.h",
         "posix/process_info.h",
 
         # These map signals to and from strings. While Fuchsia defines some of
diff --git a/third_party/crashpad/crashpad/util/posix/double_fork_and_exec.cc b/third_party/crashpad/crashpad/util/posix/double_fork_and_exec.cc
deleted file mode 100644
index 1960430954d3f6459dce688493db5c42047567b0..0000000000000000000000000000000000000000
--- a/third_party/crashpad/crashpad/util/posix/double_fork_and_exec.cc
+++ /dev/null
@@ -1,166 +0,0 @@
-// Copyright 2017 The Crashpad Authors. All rights reserved.
-//
-// 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 "util/posix/double_fork_and_exec.h"
-
-#include <stdlib.h>
-#include <string.h>
-#include <sys/wait.h>
-#include <unistd.h>
-
-#include "base/check_op.h"
-#include "base/logging.h"
-#include "base/posix/eintr_wrapper.h"
-#include "base/strings/stringprintf.h"
-#include "util/posix/close_multiple.h"
-
-namespace crashpad {
-
-bool DoubleForkAndExec(const std::vector<std::string>& argv,
-                       const std::vector<std::string>* envp,
-                       int preserve_fd,
-                       bool use_path,
-                       void (*child_function)()) {
-  DCHECK(!envp || !use_path);
-
-  // argv_c contains const char* pointers and is terminated by nullptr. This is
-  // suitable for passing to execv(). Although argv_c is not used in the parent
-  // process, it must be built in the parent process because it’s unsafe to do
-  // so in the child or grandchild process.
-  std::vector<const char*> argv_c;
-  argv_c.reserve(argv.size() + 1);
-  for (const std::string& argument : argv) {
-    argv_c.push_back(argument.c_str());
-  }
-  argv_c.push_back(nullptr);
-
-  std::vector<const char*> envp_c;
-  if (envp) {
-    envp_c.reserve(envp->size() + 1);
-    for (const std::string& variable : *envp) {
-      envp_c.push_back(variable.c_str());
-    }
-    envp_c.push_back(nullptr);
-  }
-
-  // Double-fork(). The three processes involved are parent, child, and
-  // grandchild. The grandchild will call execv(). The child exits immediately
-  // after spawning the grandchild, so the grandchild becomes an orphan and its
-  // parent process ID becomes 1. This relieves the parent and child of the
-  // responsibility to reap the grandchild with waitpid() or similar. The
-  // grandchild is expected to outlive the parent process, so the parent
-  // shouldn’t be concerned with reaping it. This approach means that accidental
-  // early termination of the handler process will not result in a zombie
-  // process.
-  pid_t pid = fork();
-  if (pid < 0) {
-    PLOG(ERROR) << "fork";
-    return false;
-  }
-
-  if (pid == 0) {
-    // Child process.
-
-    if (child_function) {
-      child_function();
-    }
-
-    // Call setsid(), creating a new process group and a new session, both led
-    // by this process. The new process group has no controlling terminal. This
-    // disconnects it from signals generated by the parent process’ terminal.
-    //
-    // setsid() is done in the child instead of the grandchild so that the
-    // grandchild will not be a session leader. If it were a session leader, an
-    // accidental open() of a terminal device without O_NOCTTY would make that
-    // terminal the controlling terminal.
-    //
-    // It’s not desirable for the grandchild to have a controlling terminal. The
-    // grandchild manages its own lifetime, such as by monitoring clients on its
-    // own and exiting when it loses all clients and when it deems it
-    // appropraite to do so. It may serve clients in different process groups or
-    // sessions than its original client, and receiving signals intended for its
-    // original client’s process group could be harmful in that case.
-    PCHECK(setsid() != -1) << "setsid";
-
-    pid = fork();
-    if (pid < 0) {
-      PLOG(FATAL) << "fork";
-    }
-
-    if (pid > 0) {
-      // Child process.
-
-      // _exit() instead of exit(), because fork() was called.
-      _exit(EXIT_SUCCESS);
-    }
-
-    // Grandchild process.
-
-    CloseMultipleNowOrOnExec(STDERR_FILENO + 1, preserve_fd);
-
-    // &argv_c[0] is a pointer to a pointer to const char data, but because of
-    // how C (not C++) works, execvp() wants a pointer to a const pointer to
-    // char data. It modifies neither the data nor the pointers, so the
-    // const_cast is safe.
-    char* const* argv_for_execv = const_cast<char* const*>(&argv_c[0]);
-
-    if (envp) {
-      // This cast is safe for the same reason that the argv_for_execv cast is.
-      char* const* envp_for_execv = const_cast<char* const*>(&envp_c[0]);
-      execve(argv_for_execv[0], argv_for_execv, envp_for_execv);
-      PLOG(FATAL) << "execve " << argv_for_execv[0];
-    }
-
-    if (use_path) {
-      execvp(argv_for_execv[0], argv_for_execv);
-      PLOG(FATAL) << "execvp " << argv_for_execv[0];
-    }
-
-    execv(argv_for_execv[0], argv_for_execv);
-    PLOG(FATAL) << "execv " << argv_for_execv[0];
-  }
-
-  // waitpid() for the child, so that it does not become a zombie process. The
-  // child normally exits quickly.
-  //
-  // Failures from this point on may result in the accumulation of a zombie, but
-  // should not be considered fatal. Log only warnings, but don’t treat these
-  // failures as a failure of the function overall.
-  int status;
-  pid_t wait_pid = HANDLE_EINTR(waitpid(pid, &status, 0));
-  if (wait_pid == -1) {
-    PLOG(WARNING) << "waitpid";
-    return true;
-  }
-  DCHECK_EQ(wait_pid, pid);
-
-  if (WIFSIGNALED(status)) {
-    int sig = WTERMSIG(status);
-    LOG(WARNING) << base::StringPrintf(
-        "intermediate process terminated by signal %d (%s)%s",
-        sig,
-        strsignal(sig),
-        WCOREDUMP(status) ? " (core dumped)" : "");
-  } else if (!WIFEXITED(status)) {
-    LOG(WARNING) << base::StringPrintf(
-        "intermediate process: unknown termination 0x%x", status);
-  } else if (WEXITSTATUS(status) != EXIT_SUCCESS) {
-    LOG(WARNING) << "intermediate process exited with code "
-                 << WEXITSTATUS(status);
-  }
-
-  return true;
-}
-
-}  // namespace crashpad
diff --git a/third_party/crashpad/crashpad/util/posix/fork_and_spawn.cc b/third_party/crashpad/crashpad/util/posix/fork_and_spawn.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c6a95bbfdcba45995b0034789c8bdb4423a25642
--- /dev/null
+++ b/third_party/crashpad/crashpad/util/posix/fork_and_spawn.cc
@@ -0,0 +1,235 @@
+// Copyright 2017 The Crashpad Authors. All rights reserved.
+//
+// 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 "util/posix/fork_and_spawn.h"
+
+#include <errno.h>
+#include <spawn.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "base/check.h"
+#include "base/check_op.h"
+#include "base/logging.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/strings/stringprintf.h"
+#include "build/build_config.h"
+#include "util/posix/close_multiple.h"
+
+extern char** environ;
+
+namespace crashpad {
+
+namespace {
+
+#if BUILDFLAG(IS_APPLE)
+
+class PosixSpawnAttr {
+ public:
+  PosixSpawnAttr() {
+    PCHECK((errno = posix_spawnattr_init(&attr_)) == 0)
+        << "posix_spawnattr_init";
+  }
+
+  PosixSpawnAttr(const PosixSpawnAttr&) = delete;
+  PosixSpawnAttr& operator=(const PosixSpawnAttr&) = delete;
+
+  ~PosixSpawnAttr() {
+    PCHECK((errno = posix_spawnattr_destroy(&attr_)) == 0)
+        << "posix_spawnattr_destroy";
+  }
+
+  void SetFlags(short flags) {
+    PCHECK((errno = posix_spawnattr_setflags(&attr_, flags)) == 0)
+        << "posix_spawnattr_setflags";
+  }
+
+  const posix_spawnattr_t* Get() const { return &attr_; }
+
+ private:
+  posix_spawnattr_t attr_;
+};
+
+class PosixSpawnFileActions {
+ public:
+  PosixSpawnFileActions() {
+    PCHECK((errno = posix_spawn_file_actions_init(&file_actions_)) == 0)
+        << "posix_spawn_file_actions_init";
+  }
+
+  PosixSpawnFileActions(const PosixSpawnFileActions&) = delete;
+  PosixSpawnFileActions& operator=(const PosixSpawnFileActions&) = delete;
+
+  ~PosixSpawnFileActions() {
+    PCHECK((errno = posix_spawn_file_actions_destroy(&file_actions_)) == 0)
+        << "posix_spawn_file_actions_destroy";
+  }
+
+  void AddInheritedFileDescriptor(int fd) {
+    PCHECK((errno = posix_spawn_file_actions_addinherit_np(&file_actions_,
+                                                           fd)) == 0)
+        << "posix_spawn_file_actions_addinherit_np";
+  }
+
+  const posix_spawn_file_actions_t* Get() const { return &file_actions_; }
+
+ private:
+  posix_spawn_file_actions_t file_actions_;
+};
+
+#endif
+
+}  // namespace
+
+bool ForkAndSpawn(const std::vector<std::string>& argv,
+                  const std::vector<std::string>* envp,
+                  int preserve_fd,
+                  bool use_path,
+                  void (*child_function)()) {
+  // argv_c contains const char* pointers and is terminated by nullptr. This is
+  // suitable for passing to posix_spawn() or posix_spawnp(). Although argv_c is
+  // not used in the parent process, it must be built in the parent process
+  // because it’s unsafe to do so in the child.
+  std::vector<const char*> argv_c;
+  argv_c.reserve(argv.size() + 1);
+  for (const std::string& argument : argv) {
+    argv_c.push_back(argument.c_str());
+  }
+  argv_c.push_back(nullptr);
+
+  std::vector<const char*> envp_c;
+  if (envp) {
+    envp_c.reserve(envp->size() + 1);
+    for (const std::string& variable : *envp) {
+      envp_c.push_back(variable.c_str());
+    }
+    envp_c.push_back(nullptr);
+  }
+
+  // The three processes involved are parent, child, and grandchild. The child
+  // exits immediately after spawning the grandchild, so the grandchild becomes
+  // an orphan and its parent process ID becomes 1. This relieves the parent and
+  // child of the responsibility to reap the grandchild with waitpid() or
+  // similar. The grandchild is expected to outlive the parent process, so the
+  // parent shouldn’t be concerned with reaping it. This approach means that
+  // accidental early termination of the handler process will not result in a
+  // zombie process.
+  pid_t pid = fork();
+  if (pid < 0) {
+    PLOG(ERROR) << "fork";
+    return false;
+  }
+
+  if (pid == 0) {
+    // Child process.
+
+    if (child_function) {
+      child_function();
+    }
+
+    // Call setsid(), creating a new process group and a new session, both led
+    // by this process. The new process group has no controlling terminal. This
+    // disconnects it from signals generated by the parent process’ terminal.
+    //
+    // setsid() is done in the child instead of the grandchild so that the
+    // grandchild will not be a session leader. If it were a session leader, an
+    // accidental open() of a terminal device without O_NOCTTY would make that
+    // terminal the controlling terminal.
+    //
+    // It’s not desirable for the grandchild to have a controlling terminal. The
+    // grandchild manages its own lifetime, such as by monitoring clients on its
+    // own and exiting when it loses all clients and when it deems it
+    // appropraite to do so. It may serve clients in different process groups or
+    // sessions than its original client, and receiving signals intended for its
+    // original client’s process group could be harmful in that case.
+    PCHECK(setsid() != -1) << "setsid";
+
+    // &argv_c[0] is a pointer to a pointer to const char data, but because of
+    // how C (not C++) works, posix_spawn() and posix_spawnp() want a pointer to
+    // a const pointer to char data. They modifies neither the data nor the
+    // pointers, so the const_cast is safe.
+    char* const* argv_for_spawn = const_cast<char* const*>(argv_c.data());
+
+    // This cast is safe for the same reason that the argv_for_spawn cast is.
+    char* const* envp_for_spawn =
+        envp ? const_cast<char* const*>(envp_c.data()) : environ;
+
+#if BUILDFLAG(IS_APPLE)
+    PosixSpawnAttr attr;
+    attr.SetFlags(POSIX_SPAWN_CLOEXEC_DEFAULT);
+
+    PosixSpawnFileActions file_actions;
+    for (int fd = 0; fd <= STDERR_FILENO; ++fd) {
+      file_actions.AddInheritedFileDescriptor(fd);
+    }
+    file_actions.AddInheritedFileDescriptor(preserve_fd);
+
+    const posix_spawnattr_t* attr_p = attr.Get();
+    const posix_spawn_file_actions_t* file_actions_p = file_actions.Get();
+#else
+    CloseMultipleNowOrOnExec(STDERR_FILENO + 1, preserve_fd);
+
+    const posix_spawnattr_t* attr_p = nullptr;
+    const posix_spawn_file_actions_t* file_actions_p = nullptr;
+#endif
+
+    auto posix_spawn_fp = use_path ? posix_spawnp : posix_spawn;
+    if ((errno = posix_spawn_fp(&pid,
+                                argv_for_spawn[0],
+                                file_actions_p,
+                                attr_p,
+                                argv_for_spawn,
+                                envp_for_spawn)) != 0) {
+      PLOG(FATAL) << (use_path ? "posix_spawnp" : "posix_spawn");
+    }
+
+    // _exit() instead of exit(), because fork() was called.
+    _exit(EXIT_SUCCESS);
+  }
+
+  // waitpid() for the child, so that it does not become a zombie process. The
+  // child normally exits quickly.
+  //
+  // Failures from this point on may result in the accumulation of a zombie, but
+  // should not be considered fatal. Log only warnings, but don’t treat these
+  // failures as a failure of the function overall.
+  int status;
+  pid_t wait_pid = HANDLE_EINTR(waitpid(pid, &status, 0));
+  if (wait_pid == -1) {
+    PLOG(WARNING) << "waitpid";
+    return true;
+  }
+  DCHECK_EQ(wait_pid, pid);
+
+  if (WIFSIGNALED(status)) {
+    int sig = WTERMSIG(status);
+    LOG(WARNING) << base::StringPrintf(
+        "intermediate process terminated by signal %d (%s)%s",
+        sig,
+        strsignal(sig),
+        WCOREDUMP(status) ? " (core dumped)" : "");
+  } else if (!WIFEXITED(status)) {
+    LOG(WARNING) << base::StringPrintf(
+        "intermediate process: unknown termination 0x%x", status);
+  } else if (WEXITSTATUS(status) != EXIT_SUCCESS) {
+    LOG(WARNING) << "intermediate process exited with code "
+                 << WEXITSTATUS(status);
+  }
+
+  return true;
+}
+
+}  // namespace crashpad
diff --git a/third_party/crashpad/crashpad/util/posix/double_fork_and_exec.h b/third_party/crashpad/crashpad/util/posix/fork_and_spawn.h
similarity index 76%
rename from third_party/crashpad/crashpad/util/posix/double_fork_and_exec.h
rename to third_party/crashpad/crashpad/util/posix/fork_and_spawn.h
index 02fc0f28f196b447132a2dcfaebdaaa5a916a38a..fc55aa3a37652e4ba18c66db90124abd9cad2e51 100644
--- a/third_party/crashpad/crashpad/util/posix/double_fork_and_exec.h
+++ b/third_party/crashpad/crashpad/util/posix/fork_and_spawn.h
@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#ifndef CRASHPAD_UTIL_POSIX_DOUBLE_FORK_AND_EXEC_H_
-#define CRASHPAD_UTIL_POSIX_DOUBLE_FORK_AND_EXEC_H_
+#ifndef CRASHPAD_UTIL_POSIX_FORK_AND_SPAWN_H_
+#define CRASHPAD_UTIL_POSIX_FORK_AND_SPAWN_H_
 
 #include <string>
 #include <vector>
@@ -23,7 +23,7 @@ namespace crashpad {
 //! \brief Executes a (grand-)child process.
 //!
 //! The grandchild process will be started through the
-//! double-`fork()`-and-`execv()` pattern. This allows the grandchild to fully
+//! `fork()`-and-`posix_spawn()` pattern. This allows the grandchild to fully
 //! disassociate from the parent. The grandchild will not be a member of the
 //! parent’s process group or session and will not have a controlling terminal,
 //! providing isolation from signals not intended for it. The grandchild’s
@@ -37,7 +37,7 @@ namespace crashpad {
 //! \param[in] argv The argument vector to start the grandchild process with.
 //!     `argv[0]` is used as the path to the executable.
 //! \param[in] envp A vector of environment variables of the form `var=value` to
-//!     be passed to `execve()`. If this value is `nullptr`, the current
+//!     be passed to `posix_spawn()`. If this value is `nullptr`, the current
 //!     environment is used.
 //! \param[in] preserve_fd A file descriptor to be inherited by the grandchild
 //!     process. This file descriptor is inherited in addition to the three file
@@ -45,16 +45,13 @@ namespace crashpad {
 //!     if no additional file descriptors are to be inherited.
 //! \param[in] use_path Whether to consult the `PATH` environment variable when
 //!     requested to start an executable at a non-absolute path. If `false`,
-//!     `execv()`, which does not consult `PATH`, will be used. If `true`,
-//!     `execvp()`, which does consult `PATH`, will be used.
+//!     `posix_spawn()`, which does not consult `PATH`, will be used. If `true`,
+//!     `posix_spawnp()`, which does consult `PATH`, will be used.
 //! \param[in] child_function If not `nullptr`, this function will be called in
-//!     the intermediate child process, prior to the second `fork()`. Take note
+//!     the intermediate child process, prior to the `posix_spawn()`. Take note
 //!     that this function will run in the context of a forked process, and must
 //!     be safe for that purpose.
 //!
-//! Setting both \a envp to a value other than `nullptr` and \a use_path to
-//! `true` is not currently supported.
-//!
 //! \return `true` on success, and `false` on failure with a message logged.
 //!     Only failures that occur in the parent process that indicate a definite
 //!     failure to start the the grandchild are reported in the return value.
@@ -63,12 +60,12 @@ namespace crashpad {
 //!     terminating. The caller assumes the responsibility for detecting such
 //!     failures, for example, by observing a failure to perform a successful
 //!     handshake with the grandchild process.
-bool DoubleForkAndExec(const std::vector<std::string>& argv,
-                       const std::vector<std::string>* envp,
-                       int preserve_fd,
-                       bool use_path,
-                       void (*child_function)());
+bool ForkAndSpawn(const std::vector<std::string>& argv,
+                  const std::vector<std::string>* envp,
+                  int preserve_fd,
+                  bool use_path,
+                  void (*child_function)());
 
 }  // namespace crashpad
 
-#endif  // CRASHPAD_UTIL_POSIX_DOUBLE_FORK_AND_EXEC_H_
+#endif  // CRASHPAD_UTIL_POSIX_FORK_AND_SPAWN_H_
