sandboxed-api/sandboxed_api/sandbox2/forkserver_bin.cc
Wiktor Garbacz 5b12071ba0 Remove WaitForSanitizers from ptrace monitor & add to global forkserver
This makes should ensure global forkserver will be single threaded before forking the sandboxees as it does not go through WaitAndFork.

Waiting for sanitizers is not needed in the monitor and should reduce latency
by 1 second for all sanitizer builds. Currently it'll always wait up to 1 seconds for the process to become single-threaded, which will never happen as monitor itself is running in a separate thread.

PiperOrigin-RevId: 530878018
Change-Id: Ie9f663848502f2738721861b0ba2dc6f3cc9f1c9
2023-05-10 05:06:18 -07:00

78 lines
2.7 KiB
C++

// Copyright 2019 Google LLC
//
// 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
//
// https://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 <sys/prctl.h>
#include <sys/socket.h>
#include <unistd.h>
#include <csignal>
#include <cstdlib>
#include "absl/flags/parse.h"
#include "absl/log/globals.h"
#include "sandboxed_api/sandbox2/comms.h"
#include "sandboxed_api/sandbox2/forkserver.h"
#include "sandboxed_api/sandbox2/sanitizer.h"
#include "sandboxed_api/util/raw_logging.h"
int main(int argc, char* argv[]) {
// Make sure the logs go stderr.
absl::SetStderrThreshold(absl::LogSeverityAtLeast::kInfo);
// Parse command line arguments.
absl::ParseCommandLine(argc, argv);
// Close all non-essential FDs to keep newly opened FD numbers consistent.
absl::Status status = sandbox2::sanitizer::CloseAllFDsExcept(
{0, 1, 2, sandbox2::Comms::kSandbox2ClientCommsFD});
if (!status.ok()) {
SAPI_RAW_LOG(WARNING, "Closing non-essential FDs failed");
}
// Make the process' name easily recognizable with ps/pstree.
if (prctl(PR_SET_NAME, "S2-FORK-SERV", 0, 0, 0) != 0) {
SAPI_RAW_PLOG(WARNING, "prctl(PR_SET_NAME, 'S2-FORK-SERV')");
}
// Don't react (with stack-tracing) to SIGTERM's sent from other processes
// (e.g. from the borglet or SubProcess). This ForkServer should go down if
// the parent goes down (or if the GlobalForkServerComms is closed), which is
// assured by prctl(PR_SET_PDEATHSIG, SIGKILL) being called in the
// ForkServer::Initialize(). We don't want to change behavior of non-global
// ForkServers, hence it's called here and not in the
// ForkServer::Initialize().
struct sigaction sa;
sa.sa_handler = SIG_IGN;
sa.sa_flags = 0;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGTERM, &sa, nullptr) == -1) {
SAPI_RAW_PLOG(WARNING, "sigaction(SIGTERM, sa_handler=SIG_IGN)");
}
sandbox2::Comms comms(sandbox2::Comms::kDefaultConnection);
sandbox2::ForkServer fork_server(&comms);
sandbox2::sanitizer::WaitForSanitizer();
while (!fork_server.IsTerminated()) {
pid_t child_pid = fork_server.ServeRequest();
if (child_pid == 0) {
// FORKSERVER_FORK sent to the global forkserver. This case does not make
// sense, we thus kill the process here.
_Exit(0);
}
}
SAPI_RAW_VLOG(1, "ForkServer Comms closed. Exiting");
}