Automated g4 rollback of commit 7f520a8286c39c5145b6d816cd0be5a6b7b18250.
*** Reason for rollback ***
This broke Bazel CI on freebsd:
http://ci.bazel.io/view/Dashboard/job/Bazel/JAVA_VERSION=1.8,PLATFORM_NAME=freebsd-11/1516/console#
*** Original change description ***
Refactor process-wrapper code so the spawn/wait code is pluggable.
In an upcoming change I'll reintroduce the new platform-specific implementations that can kill and wait for all descendant processes spawned by the wrapped process.
This has no functional changes.
PiperOrigin-RevId: 156884488
diff --git a/src/main/tools/BUILD b/src/main/tools/BUILD
index 5ed4ac9..72aff63 100644
--- a/src/main/tools/BUILD
+++ b/src/main/tools/BUILD
@@ -19,9 +19,6 @@
"//src:windows_msvc": ["process-wrapper-windows.cc"],
"//conditions:default": [
"process-wrapper.cc",
- "process-wrapper.h",
- "process-wrapper-legacy.cc",
- "process-wrapper-legacy.h",
],
}),
linkopts = ["-lm"],
diff --git a/src/main/tools/process-wrapper-legacy.cc b/src/main/tools/process-wrapper-legacy.cc
deleted file mode 100644
index 2ebc593..0000000
--- a/src/main/tools/process-wrapper-legacy.cc
+++ /dev/null
@@ -1,100 +0,0 @@
-// Copyright 2017 The Bazel 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 "src/main/tools/process-wrapper-legacy.h"
-
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <vector>
-
-#include "src/main/tools/logging.h"
-#include "src/main/tools/process-tools.h"
-#include "src/main/tools/process-wrapper.h"
-
-pid_t LegacyProcessWrapper::child_pid = 0;
-volatile sig_atomic_t LegacyProcessWrapper::last_signal = 0;
-
-void LegacyProcessWrapper::RunCommand() {
- SpawnChild();
- WaitForChild();
-}
-
-void LegacyProcessWrapper::SpawnChild() {
- child_pid = fork();
- if (child_pid < 0) {
- DIE("fork");
- } else if (child_pid == 0) {
- // In child.
- if (setsid() < 0) {
- DIE("setsid");
- }
- ClearSignalMask();
-
- // Force umask to include read and execute for everyone, to make output
- // permissions predictable.
- umask(022);
-
- // Does not return unless something went wrong.
- if (execvp(opt.args[0], opt.args.data()) < 0) {
- DIE("execvp(%s, ...)", opt.args[0]);
- }
- }
-}
-
-void LegacyProcessWrapper::WaitForChild() {
- // Set up a signal handler which kills all subprocesses when the given signal
- // is triggered.
- InstallSignalHandler(SIGALRM, OnSignal);
- InstallSignalHandler(SIGTERM, OnSignal);
- InstallSignalHandler(SIGINT, OnSignal);
- if (opt.timeout_secs > 0) {
- SetTimeout(opt.timeout_secs);
- }
-
- int status = WaitChild(child_pid);
-
- // The child is done for, but may have grandchildren that we still have to
- // kill.
- kill(-child_pid, SIGKILL);
-
- if (last_signal > 0) {
- // Don't trust the exit code if we got a timeout or signal.
- InstallDefaultSignalHandler(last_signal);
- raise(last_signal);
- } else if (WIFEXITED(status)) {
- exit(WEXITSTATUS(status));
- } else {
- int sig = WTERMSIG(status);
- InstallDefaultSignalHandler(sig);
- raise(sig);
- }
-}
-
-// Called when timeout or signal occurs.
-void LegacyProcessWrapper::OnSignal(int sig) {
- last_signal = sig;
-
- if (sig == SIGALRM) {
- // SIGALRM represents a timeout, so we should give the process a bit of time
- // to die gracefully if it needs it.
- KillEverything(child_pid, true, opt.kill_delay_secs);
- } else {
- // Signals should kill the process quickly, as it's typically blocking the
- // return of the prompt after a user hits "Ctrl-C".
- KillEverything(child_pid, false, opt.kill_delay_secs);
- }
-}
diff --git a/src/main/tools/process-wrapper-legacy.h b/src/main/tools/process-wrapper-legacy.h
deleted file mode 100644
index 5cea547..0000000
--- a/src/main/tools/process-wrapper-legacy.h
+++ /dev/null
@@ -1,49 +0,0 @@
-// Copyright 2017 The Bazel 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.
-
-#ifndef SRC_MAIN_TOOLS_PROCESS_WRAPPER_LEGACY_H_
-#define SRC_MAIN_TOOLS_PROCESS_WRAPPER_LEGACY_H_
-
-#include <signal.h>
-#include <vector>
-
-// The process-wrapper implementation that was used until and including Bazel
-// 0.4.5. Waits for the wrapped process to exit and then kills its process
-// group. Works on all POSIX operating systems (tested on Linux, macOS,
-// FreeBSD).
-//
-// Caveats:
-// - Killing just the process group of the spawned child means that daemons or
-// other processes spawned by the child may not be killed if they change their
-// process group.
-// - Does not wait for grandchildren to exit, thus processes spawned by the
-// child that could not be killed will linger around in the background.
-// - Has a PID reuse race condition, because the kill() to the process group is
-// sent after waitpid() was called on the main child.
-class LegacyProcessWrapper {
- public:
- // Run the command specified in the `opt.args` array and kill it after
- // `opt.timeout_secs` seconds.
- static void RunCommand();
-
- private:
- static void SpawnChild();
- static void WaitForChild();
- static void OnSignal(int sig);
-
- static pid_t child_pid;
- static volatile sig_atomic_t last_signal;
-};
-
-#endif
diff --git a/src/main/tools/process-wrapper.cc b/src/main/tools/process-wrapper.cc
index 09c1a88..c60de6e 100644
--- a/src/main/tools/process-wrapper.cc
+++ b/src/main/tools/process-wrapper.cc
@@ -22,8 +22,6 @@
// die with raise(SIGTERM) even if the child process handles SIGTERM with
// exit(0).
-#include "src/main/tools/process-wrapper.h"
-
#include <err.h>
#include <errno.h>
#include <signal.h>
@@ -40,9 +38,21 @@
#include "src/main/tools/logging.h"
#include "src/main/tools/process-tools.h"
-#include "src/main/tools/process-wrapper-legacy.h"
-struct Options opt;
+static double global_kill_delay;
+static pid_t global_child_pid;
+static volatile sig_atomic_t global_signal;
+
+// Options parsing result.
+struct Options {
+ double timeout_secs;
+ double kill_delay_secs;
+ std::string stdout_path;
+ std::string stderr_path;
+ std::vector<char *> args;
+};
+
+static struct Options opt;
// Print out a usage error and exit with EXIT_FAILURE.
static void Usage(char *program_name) {
@@ -76,9 +86,83 @@
opt.args.push_back(nullptr);
}
+// Called when timeout or signal occurs.
+void OnSignal(int sig) {
+ global_signal = sig;
+
+ // Nothing to do if we received a signal before spawning the child.
+ if (global_child_pid == -1) {
+ return;
+ }
+
+ if (sig == SIGALRM) {
+ // SIGALRM represents a timeout, so we should give the process a bit of
+ // time to die gracefully if it needs it.
+ KillEverything(global_child_pid, true, global_kill_delay);
+ } else {
+ // Signals should kill the process quickly, as it's typically blocking
+ // the return of the prompt after a user hits "Ctrl-C".
+ KillEverything(global_child_pid, false, global_kill_delay);
+ }
+}
+
+// Run the command specified by the argv array and kill it after timeout
+// seconds.
+static void SpawnCommand(const std::vector<char *> &args, double timeout_secs) {
+ global_child_pid = fork();
+ if (global_child_pid < 0) {
+ DIE("fork");
+ } else if (global_child_pid == 0) {
+ // In child.
+ if (setsid() < 0) {
+ DIE("setsid");
+ }
+ ClearSignalMask();
+
+ // Force umask to include read and execute for everyone, to make
+ // output permissions predictable.
+ umask(022);
+
+ // Does not return unless something went wrong.
+ if (execvp(args[0], args.data()) < 0) {
+ DIE("execvp(%s, ...)", args[0]);
+ }
+ } else {
+ // In parent.
+
+ // Set up a signal handler which kills all subprocesses when the given
+ // signal is triggered.
+ InstallSignalHandler(SIGALRM, OnSignal);
+ InstallSignalHandler(SIGTERM, OnSignal);
+ InstallSignalHandler(SIGINT, OnSignal);
+ if (timeout_secs > 0) {
+ SetTimeout(timeout_secs);
+ }
+
+ int status = WaitChild(global_child_pid);
+
+ // The child is done for, but may have grandchildren that we still have to
+ // kill.
+ kill(-global_child_pid, SIGKILL);
+
+ if (global_signal > 0) {
+ // Don't trust the exit code if we got a timeout or signal.
+ InstallDefaultSignalHandler(global_signal);
+ raise(global_signal);
+ } else if (WIFEXITED(status)) {
+ exit(WEXITSTATUS(status));
+ } else {
+ int sig = WTERMSIG(status);
+ InstallDefaultSignalHandler(sig);
+ raise(sig);
+ }
+ }
+}
+
int main(int argc, char *argv[]) {
std::vector<char *> args(argv, argv + argc);
ParseCommandLine(args);
+ global_kill_delay = opt.kill_delay_secs;
SwitchToEuid();
SwitchToEgid();
@@ -86,7 +170,7 @@
Redirect(opt.stdout_path, STDOUT_FILENO);
Redirect(opt.stderr_path, STDERR_FILENO);
- LegacyProcessWrapper::RunCommand();
+ SpawnCommand(opt.args, opt.timeout_secs);
return 0;
}
diff --git a/src/main/tools/process-wrapper.h b/src/main/tools/process-wrapper.h
deleted file mode 100644
index 061eeac..0000000
--- a/src/main/tools/process-wrapper.h
+++ /dev/null
@@ -1,32 +0,0 @@
-// Copyright 2017 The Bazel 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.
-
-#ifndef SRC_MAIN_TOOLS_PROCESS_WRAPPER_H_
-#define SRC_MAIN_TOOLS_PROCESS_WRAPPER_H_
-
-#include <string>
-#include <vector>
-
-// Options parsing result.
-struct Options {
- double timeout_secs;
- double kill_delay_secs;
- std::string stdout_path;
- std::string stderr_path;
- std::vector<char *> args;
-};
-
-extern struct Options opt;
-
-#endif
