sandboxed-api/sandboxed_api/sandbox2/forkserver_bin.cc
Christian Blichmann dbaf95c724 Move utility code into sandboxed_api/util
This change should make it less confusing where utility code comes from.
Having it in two places made sense when we were debating whether to publish
Sandbox2 separately, but not any longer.

Follow-up changes will move `sandbox2/util.h` and rename the remaining
`sandbox2/util` folder.

PiperOrigin-RevId: 351601640
Change-Id: I6256845261f610e590c25e2c59851cc51da2d778
2021-01-13 09:25:52 -08:00

70 lines
2.4 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
//
// 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 <sys/prctl.h>
#include <sys/socket.h>
#include <unistd.h>
#include <csignal>
#include <cstdlib>
#include "absl/base/attributes.h"
#include "absl/strings/str_cat.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"
#include "sandboxed_api/util/strerror.h"
int main() {
// Make sure the logs go stderr.
google::LogToStderr();
// Close all non-essential FDs to keep newly opened FD numbers consistent.
sandbox2::sanitizer::CloseAllFDsExcept(
{0, 1, 2, sandbox2::Comms::kSandbox2ClientCommsFD});
// 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::kSandbox2ClientCommsFD);
sandbox2::ForkServer fork_server(&comms);
while (true) {
pid_t child_pid = fork_server.ServeRequest();
if (!child_pid) {
// FORKSERVER_FORK sent to the global forkserver. This case does not make
// sense, we thus kill the process here.
exit(0);
}
}
}