/*
- * Copyright 2015 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <sys/prctl.h>
#endif
#include <fcntl.h>
-#include <poll.h>
-#include <unistd.h>
-
-#include <array>
#include <algorithm>
+#include <array>
#include <system_error>
#include <boost/container/flat_set.hpp>
#include <folly/ScopeGuard.h>
#include <folly/String.h>
#include <folly/io/Cursor.h>
-
-extern char** environ;
+#include <folly/lang/Assume.h>
+#include <folly/portability/Sockets.h>
+#include <folly/portability/Stdlib.h>
+#include <folly/portability/SysSyscall.h>
+#include <folly/portability/Unistd.h>
+#include <folly/system/Shell.h>
constexpr int kExecFailure = 127;
constexpr int kChildFailure = 126;
namespace folly {
+ProcessReturnCode ProcessReturnCode::make(int status) {
+ if (!WIFEXITED(status) && !WIFSIGNALED(status)) {
+ throw std::runtime_error(
+ to<std::string>("Invalid ProcessReturnCode: ", status));
+ }
+ return ProcessReturnCode(status);
+}
+
+ProcessReturnCode::ProcessReturnCode(ProcessReturnCode&& p) noexcept
+ : rawStatus_(p.rawStatus_) {
+ p.rawStatus_ = ProcessReturnCode::RV_NOT_STARTED;
+}
+
+ProcessReturnCode& ProcessReturnCode::operator=(ProcessReturnCode&& p)
+ noexcept {
+ rawStatus_ = p.rawStatus_;
+ p.rawStatus_ = ProcessReturnCode::RV_NOT_STARTED;
+ return *this;
+}
+
ProcessReturnCode::State ProcessReturnCode::state() const {
- if (rawStatus_ == RV_NOT_STARTED) return NOT_STARTED;
- if (rawStatus_ == RV_RUNNING) return RUNNING;
- if (WIFEXITED(rawStatus_)) return EXITED;
- if (WIFSIGNALED(rawStatus_)) return KILLED;
- throw std::runtime_error(to<std::string>(
- "Invalid ProcessReturnCode: ", rawStatus_));
+ if (rawStatus_ == RV_NOT_STARTED) {
+ return NOT_STARTED;
+ }
+ if (rawStatus_ == RV_RUNNING) {
+ return RUNNING;
+ }
+ if (WIFEXITED(rawStatus_)) {
+ return EXITED;
+ }
+ if (WIFSIGNALED(rawStatus_)) {
+ return KILLED;
+ }
+ assume_unreachable();
}
void ProcessReturnCode::enforce(State expected) const {
return to<std::string>("killed by signal ", killSignal(),
(coreDumped() ? " (core dumped)" : ""));
}
- CHECK(false); // unreached
+ assume_unreachable();
}
CalledProcessError::CalledProcessError(ProcessReturnCode rc)
- : returnCode_(rc),
- what_(returnCode_.str()) {
-}
+ : SubprocessError(rc.str()), returnCode_(rc) {}
-SubprocessSpawnError::SubprocessSpawnError(const char* executable,
- int errCode,
- int errnoValue)
- : errnoValue_(errnoValue),
- what_(to<std::string>(errCode == kExecFailure ?
- "failed to execute " :
- "error preparing to execute ",
- executable, ": ", errnoStr(errnoValue))) {
+static inline std::string toSubprocessSpawnErrorMessage(
+ char const* executable,
+ int errCode,
+ int errnoValue) {
+ auto prefix = errCode == kExecFailure ? "failed to execute "
+ : "error preparing to execute ";
+ return to<std::string>(prefix, executable, ": ", errnoStr(errnoValue));
}
+SubprocessSpawnError::SubprocessSpawnError(
+ const char* executable,
+ int errCode,
+ int errnoValue)
+ : SubprocessError(
+ toSubprocessSpawnErrorMessage(executable, errCode, errnoValue)),
+ errnoValue_(errnoValue) {}
+
namespace {
// Copy pointers to the given strings in a format suitable for posix_spawn
}
}
-} // namespace
+} // namespace
Subprocess::Options& Subprocess::Options::fd(int fd, int action) {
if (action == Subprocess::PIPE) {
return *this;
}
+Subprocess::Subprocess() {}
+
Subprocess::Subprocess(
const std::vector<std::string>& argv,
const Options& options,
const char* executable,
- const std::vector<std::string>* env)
- : pid_(-1),
- returnCode_(RV_NOT_STARTED) {
+ const std::vector<std::string>* env) {
if (argv.empty()) {
throw std::invalid_argument("argv must not be empty");
}
- if (!executable) executable = argv[0].c_str();
+ if (!executable) {
+ executable = argv[0].c_str();
+ }
spawn(cloneStrings(argv), executable, options, env);
}
Subprocess::Subprocess(
const std::string& cmd,
const Options& options,
- const std::vector<std::string>* env)
- : pid_(-1),
- returnCode_(RV_NOT_STARTED) {
+ const std::vector<std::string>* env) {
if (options.usePath_) {
throw std::invalid_argument("usePath() not allowed when running in shell");
}
- const char* shell = getenv("SHELL");
- if (!shell) {
- shell = "/bin/sh";
- }
- std::unique_ptr<const char*[]> argv(new const char*[4]);
- argv[0] = shell;
- argv[1] = "-c";
- argv[2] = cmd.c_str();
- argv[3] = nullptr;
- spawn(std::move(argv), shell, options, env);
+ std::vector<std::string> argv = {"/bin/sh", "-c", cmd};
+ spawn(cloneStrings(argv), argv[0].c_str(), options, env);
}
Subprocess::~Subprocess() {
CHECK_NE(returnCode_.state(), ProcessReturnCode::RUNNING)
<< "Subprocess destroyed without reaping child";
- closeAll();
}
namespace {
-void closeChecked(int fd) {
- checkUnixError(::close(fd), "close");
-}
struct ChildErrorInfo {
int errCode;
int errnoValue;
};
-FOLLY_NORETURN void childError(int errFd, int errCode, int errnoValue);
-void childError(int errFd, int errCode, int errnoValue) {
+[[noreturn]] void childError(int errFd, int errCode, int errnoValue) {
ChildErrorInfo info = {errCode, errnoValue};
// Write the error information over the pipe to our parent process.
// We can't really do anything else if this write call fails.
_exit(errCode);
}
-} // namespace
-
-void Subprocess::closeAll() {
- for (auto& p : pipes_) {
- closeChecked(p.parentFd);
- }
- pipes_.clear();
-}
+} // namespace
void Subprocess::setAllNonBlocking() {
for (auto& p : pipes_) {
- int fd = p.parentFd;
+ int fd = p.pipe.fd();
int flags = ::fcntl(fd, F_GETFL);
checkUnixError(flags, "fcntl");
int r = ::fcntl(fd, F_SETFL, flags | O_NONBLOCK);
// Make a copy, we'll mutate options
Options options(optionsIn);
- // On error, close all of the pipes_
- auto pipesGuard = makeGuard([&] {
- for (auto& p : this->pipes_) {
- CHECK_ERR(::close(p.parentFd));
- }
- });
+ // On error, close all pipes_ (ignoring errors, but that seems fine here).
+ auto pipesGuard = makeGuard([this] { pipes_.clear(); });
// Create a pipe to use to receive error information from the child,
// in case it fails before calling exec()
// doesn't need to reset the flag on its end, as we always dup2() the fd,
// and dup2() fds don't share the close-on-exec flag.
#if FOLLY_HAVE_PIPE2
+ // If possible, set close-on-exec atomically. Otherwise, a concurrent
+ // Subprocess invocation can fork() between "pipe" and "fnctl",
+ // causing FDs to leak.
r = ::pipe2(fds, O_CLOEXEC);
checkUnixError(r, "pipe2");
#else
r = fcntl(fds[1], F_SETFD, FD_CLOEXEC);
checkUnixError(r, "set FD_CLOEXEC");
#endif
- PipeInfo pinfo;
- pinfo.direction = p.second;
+ pipes_.emplace_back();
+ Pipe& pipe = pipes_.back();
+ pipe.direction = p.second;
int cfd;
if (p.second == PIPE_IN) {
// Child gets reading end
- pinfo.parentFd = fds[1];
+ pipe.pipe = folly::File(fds[1], /*ownsFd=*/true);
cfd = fds[0];
} else {
- pinfo.parentFd = fds[0];
+ pipe.pipe = folly::File(fds[0], /*ownsFd=*/true);
cfd = fds[1];
}
p.second = cfd; // ensure it gets dup2()ed
- pinfo.childFd = p.first;
+ pipe.childFd = p.first;
childFds.push_back(cfd);
- pipes_.push_back(pinfo);
}
}
// Call c_str() here, as it's not necessarily safe after fork.
const char* childDir =
options.childDir_.empty() ? nullptr : options.childDir_.c_str();
- pid_t pid = vfork();
+
+ pid_t pid;
+#ifdef __linux__
+ if (options.cloneFlags_) {
+ pid = syscall(SYS_clone, *options.cloneFlags_, 0, nullptr, nullptr);
+ checkUnixError(pid, errno, "clone");
+ } else {
+#endif
+ pid = vfork();
+ checkUnixError(pid, errno, "vfork");
+#ifdef __linux__
+ }
+#endif
if (pid == 0) {
int errnoValue = prepareChild(options, &oldSignals, childDir);
if (errnoValue != 0) {
// If we get here, exec() failed.
childError(errFd, kExecFailure, errnoValue);
}
- // In parent. Make sure vfork() succeeded.
- checkUnixError(pid, errno, "vfork");
// Child is alive. We have to be very careful about throwing after this
// point. We are inside the constructor, so if we throw the Subprocess
// child has exited and can be immediately waited for. In all other cases,
// we have no way of cleaning up the child.
pid_ = pid;
- returnCode_ = ProcessReturnCode(RV_RUNNING);
+ returnCode_ = ProcessReturnCode::makeRunning();
}
int Subprocess::prepareChild(const Options& options,
#if __linux__
// Opt to receive signal on parent death, if requested
if (options.parentDeathSignal_ != 0) {
- if (prctl(PR_SET_PDEATHSIG, options.parentDeathSignal_, 0, 0, 0) == -1) {
+ const auto parentDeathSignal =
+ static_cast<unsigned long>(options.parentDeathSignal_);
+ if (prctl(PR_SET_PDEATHSIG, parentDeathSignal, 0, 0, 0) == -1) {
return errno;
}
}
}
}
+ // The user callback comes last, so that the child is otherwise all set up.
+ if (options.dangerousPostForkPreExecCallback_) {
+ if (int error = (*options.dangerousPostForkPreExecCallback_)()) {
+ return error;
+ }
+ }
+
return 0;
}
throw SubprocessSpawnError(executable, info.errCode, info.errnoValue);
}
-ProcessReturnCode Subprocess::poll() {
+ProcessReturnCode Subprocess::poll(struct rusage* ru) {
returnCode_.enforce(ProcessReturnCode::RUNNING);
DCHECK_GT(pid_, 0);
int status;
- pid_t found = ::waitpid(pid_, &status, WNOHANG);
- checkUnixError(found, "waitpid");
+ pid_t found = ::wait4(pid_, &status, WNOHANG, ru);
+ // The spec guarantees that EINTR does not occur with WNOHANG, so the only
+ // two remaining errors are ECHILD (other code reaped the child?), or
+ // EINVAL (cosmic rays?), both of which merit an abort:
+ PCHECK(found != -1) << "waitpid(" << pid_ << ", &status, WNOHANG)";
if (found != 0) {
- returnCode_ = ProcessReturnCode(status);
+ // Though the child process had quit, this call does not close the pipes
+ // since its descendants may still be using them.
+ returnCode_ = ProcessReturnCode::make(status);
pid_ = -1;
}
return returnCode_;
do {
found = ::waitpid(pid_, &status, 0);
} while (found == -1 && errno == EINTR);
- checkUnixError(found, "waitpid");
+ // The only two remaining errors are ECHILD (other code reaped the
+ // child?), or EINVAL (cosmic rays?), and both merit an abort:
+ PCHECK(found != -1) << "waitpid(" << pid_ << ", &status, WNOHANG)";
+ // Though the child process had quit, this call does not close the pipes
+ // since its descendants may still be using them.
DCHECK_EQ(found, pid_);
- returnCode_ = ProcessReturnCode(status);
+ returnCode_ = ProcessReturnCode::make(status);
pid_ = -1;
return returnCode_;
}
namespace {
-std::pair<const uint8_t*, size_t> queueFront(const IOBufQueue& queue) {
+ByteRange queueFront(const IOBufQueue& queue) {
auto* p = queue.front();
- if (!p) return std::make_pair(nullptr, 0);
- return io::Cursor(p).peek();
+ if (!p) {
+ return ByteRange{};
+ }
+ return io::Cursor(p).peekBytes();
}
// fd write
bool handleWrite(int fd, IOBufQueue& queue) {
for (;;) {
- auto p = queueFront(queue);
- if (p.second == 0) {
+ auto b = queueFront(queue);
+ if (b.empty()) {
return true; // EOF
}
- ssize_t n = writeNoInt(fd, p.first, p.second);
+ ssize_t n = writeNoInt(fd, b.data(), b.size());
if (n == -1 && errno == EAGAIN) {
return false;
}
}
}
-} // namespace
+} // namespace
std::pair<std::string, std::string> Subprocess::communicate(
StringPiece input) {
void Subprocess::communicate(FdCallback readCallback,
FdCallback writeCallback) {
+ // This serves to prevent wait() followed by communicate(), but if you
+ // legitimately need that, send a patch to delete this line.
returnCode_.enforce(ProcessReturnCode::RUNNING);
setAllNonBlocking();
std::vector<pollfd> fds;
fds.reserve(pipes_.size());
- std::vector<int> toClose;
+ std::vector<size_t> toClose; // indexes into pipes_
toClose.reserve(pipes_.size());
while (!pipes_.empty()) {
for (auto& p : pipes_) {
pollfd pfd;
- pfd.fd = p.parentFd;
+ pfd.fd = p.pipe.fd();
// Yes, backwards, PIPE_IN / PIPE_OUT are defined from the
// child's point of view.
if (!p.enabled) {
for (size_t i = 0; i < pipes_.size(); ++i) {
auto& p = pipes_[i];
- DCHECK_EQ(fds[i].fd, p.parentFd);
+ auto parentFd = p.pipe.fd();
+ DCHECK_EQ(fds[i].fd, parentFd);
short events = fds[i].revents;
bool closed = false;
if (events & POLLOUT) {
DCHECK(!(events & POLLIN));
- if (writeCallback(p.parentFd, p.childFd)) {
+ if (writeCallback(parentFd, p.childFd)) {
toClose.push_back(i);
closed = true;
}
// on) end of file
if (events & (POLLIN | POLLHUP)) {
DCHECK(!(events & POLLOUT));
- if (readCallback(p.parentFd, p.childFd)) {
+ if (readCallback(parentFd, p.childFd)) {
toClose.push_back(i);
closed = true;
}
// Close the fds in reverse order so the indexes hold after erase()
for (int idx : boost::adaptors::reverse(toClose)) {
auto pos = pipes_.begin() + idx;
- closeChecked(pos->parentFd);
+ pos->pipe.close(); // Throws on error
pipes_.erase(pos);
}
}
return pipes_[findByChildFd(childFd)].enabled;
}
-int Subprocess::findByChildFd(int childFd) const {
+size_t Subprocess::findByChildFd(int childFd) const {
auto pos = std::lower_bound(
pipes_.begin(), pipes_.end(), childFd,
- [] (const PipeInfo& info, int fd) { return info.childFd < fd; });
+ [] (const Pipe& pipe, int fd) { return pipe.childFd < fd; });
if (pos == pipes_.end() || pos->childFd != childFd) {
throw std::invalid_argument(folly::to<std::string>(
"child fd not found ", childFd));
void Subprocess::closeParentFd(int childFd) {
int idx = findByChildFd(childFd);
- closeChecked(pipes_[idx].parentFd);
+ pipes_[idx].pipe.close(); // May throw
pipes_.erase(pipes_.begin() + idx);
}
+std::vector<Subprocess::ChildPipe> Subprocess::takeOwnershipOfPipes() {
+ std::vector<Subprocess::ChildPipe> pipes;
+ for (auto& p : pipes_) {
+ pipes.emplace_back(p.childFd, std::move(p.pipe));
+ }
+ // release memory
+ std::vector<Pipe>().swap(pipes_);
+ return pipes;
+}
+
namespace {
class Initializer {
Initializer initializer;
-} // namespace
+} // namespace
-} // namespace folly
+} // namespace folly
projects / folly.git / blobdiff