/*
- * Copyright 2012 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.
* limitations under the License.
*/
-#include "folly/Subprocess.h"
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <folly/Subprocess.h>
+
+#if __linux__
+#include <sys/prctl.h>
+#endif
#include <fcntl.h>
-#include <poll.h>
-#include <unistd.h>
-#include <wait.h>
-#include <array>
#include <algorithm>
+#include <array>
#include <system_error>
#include <boost/container/flat_set.hpp>
#include <glog/logging.h>
-#include "folly/Conv.h"
-#include "folly/ScopeGuard.h"
-#include "folly/String.h"
-#include "folly/experimental/io/Cursor.h"
-
-extern char** environ;
+#include <folly/Conv.h>
+#include <folly/Exception.h>
+#include <folly/ScopeGuard.h>
+#include <folly/String.h>
+#include <folly/io/Cursor.h>
+#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 s) const {
- if (state() != s) {
- throw std::logic_error(to<std::string>("Invalid state ", s));
+void ProcessReturnCode::enforce(State expected) const {
+ State s = state();
+ if (s != expected) {
+ throw std::logic_error(to<std::string>(
+ "Bad use of ProcessReturnCode; state is ", s, " expected ", expected
+ ));
}
}
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) {}
+
+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
std::unique_ptr<const char*[]> cloneStrings(const std::vector<std::string>& s) {
std::unique_ptr<const char*[]> d(new const char*[s.size() + 1]);
- for (int i = 0; i < s.size(); i++) {
+ for (size_t i = 0; i < s.size(); i++) {
d[i] = s[i].c_str();
}
d[s.size()] = nullptr;
return d;
}
-// Helper to throw std::system_error
-void throwSystemError(int err, const char* msg) __attribute__((noreturn));
-void throwSystemError(int err, const char* msg) {
- throw std::system_error(err, std::system_category(), msg);
-}
-
-// Helper to throw std::system_error from errno
-void throwSystemError(const char* msg) __attribute__((noreturn));
-void throwSystemError(const char* msg) {
- throwSystemError(errno, msg);
-}
-
-// Check a Posix return code (0 on success, error number on error), throw
-// on error.
-void checkPosixError(int err, const char* msg) {
- if (err != 0) {
- throwSystemError(err, msg);
- }
-}
-
-// Check a traditional Uinx return code (-1 and sets errno on error), throw
-// on error.
-void checkUnixError(ssize_t ret, const char* msg) {
- if (ret == -1) {
- throwSystemError(msg);
- }
-}
-
// Check a wait() status, throw on non-successful
void checkStatus(ProcessReturnCode returnCode) {
if (returnCode.state() != ProcessReturnCode::EXITED ||
}
}
-} // 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() {
- if (returnCode_.state() == ProcessReturnCode::RUNNING) {
- LOG(ERROR) << "Subprocess destroyed without reaping; killing child.";
- try {
- kill();
- wait();
- } catch (...) {
- LOG(FATAL) << "Killing child failed, terminating: "
- << exceptionStr(std::current_exception());
- }
- }
- try {
- closeAll();
- } catch (...) {
- LOG(FATAL) << "close failed, terminating: "
- << exceptionStr(std::current_exception());
- }
+ CHECK_NE(returnCode_.state(), ProcessReturnCode::RUNNING)
+ << "Subprocess destroyed without reaping child";
}
namespace {
-void closeChecked(int fd) {
- checkUnixError(::close(fd), "close");
-}
-} // namespace
-void Subprocess::closeAll() {
- for (auto& p : pipes_) {
- closeChecked(p.parentFd);
- }
- pipes_.clear();
+struct ChildErrorInfo {
+ 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.
+ writeNoInt(errFd, &info, sizeof(info));
+ // exit
+ _exit(errCode);
}
+} // 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 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()
+ int errFds[2];
+#if FOLLY_HAVE_PIPE2
+ checkUnixError(::pipe2(errFds, O_CLOEXEC), "pipe2");
+#else
+ checkUnixError(::pipe(errFds), "pipe");
+#endif
+ SCOPE_EXIT {
+ CHECK_ERR(::close(errFds[0]));
+ if (errFds[1] >= 0) {
+ CHECK_ERR(::close(errFds[1]));
+ }
+ };
+
+#if !FOLLY_HAVE_PIPE2
+ // Ask the child to close the read end of the error pipe.
+ checkUnixError(fcntl(errFds[0], F_SETFD, FD_CLOEXEC), "set FD_CLOEXEC");
+ // Set the close-on-exec flag on the write side of the pipe.
+ // This way the pipe will be closed automatically in the child if execve()
+ // succeeds. If the exec fails the child can write error information to the
+ // pipe.
+ checkUnixError(fcntl(errFds[1], F_SETFD, FD_CLOEXEC), "set FD_CLOEXEC");
+#endif
+
+ // Perform the actual work of setting up pipes then forking and
+ // executing the child.
+ spawnInternal(std::move(argv), executable, options, env, errFds[1]);
+
+ // After spawnInternal() returns the 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 object will have never existed, and the
+ // destructor will never be called.
+ //
+ // We should only throw if we got an error via the errFd, and we know the
+ // child has exited and can be immediately waited for. In all other cases,
+ // we have no way of cleaning up the child.
+
+ // Close writable side of the errFd pipe in the parent process
+ CHECK_ERR(::close(errFds[1]));
+ errFds[1] = -1;
+
+ // Read from the errFd pipe, to tell if the child ran into any errors before
+ // calling exec()
+ readChildErrorPipe(errFds[0], executable);
+
+ // We have fully succeeded now, so release the guard on pipes_
+ pipesGuard.dismiss();
+}
+
+void Subprocess::spawnInternal(
+ std::unique_ptr<const char*[]> argv,
+ const char* executable,
+ Options& options,
+ const std::vector<std::string>* env,
+ int errFd) {
// Parent work, pre-fork: create pipes
std::vector<int> childFds;
+ // Close all of the childFds as we leave this scope
+ SCOPE_EXIT {
+ // These are only pipes, closing them shouldn't fail
+ for (int cfd : childFds) {
+ CHECK_ERR(::close(cfd));
+ }
+ };
+
+ int r;
for (auto& p : options.fdActions_) {
if (p.second == PIPE_IN || p.second == PIPE_OUT) {
int fds[2];
- int r = ::pipe(fds);
+ // We're setting both ends of the pipe as close-on-exec. The child
+ // 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 = ::pipe(fds);
checkUnixError(r, "pipe");
- PipeInfo pinfo;
- pinfo.direction = p.second;
+ r = fcntl(fds[0], F_SETFD, FD_CLOEXEC);
+ checkUnixError(r, "set FD_CLOEXEC");
+ r = fcntl(fds[1], F_SETFD, FD_CLOEXEC);
+ checkUnixError(r, "set FD_CLOEXEC");
+#endif
+ 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);
}
}
envVec = environ;
}
- pid_t pid = vfork();
- if (pid == 0) {
- runChild(executable, argVec, envVec, options);
- // This should never return, but there's nothing else we can do here.
- abort();
- }
+ // Block all signals around vfork; see http://ewontfix.com/7/.
+ //
+ // As the child may run in the same address space as the parent until
+ // the actual execve() system call, any (custom) signal handlers that
+ // the parent has might alter parent's memory if invoked in the child,
+ // with undefined results. So we block all signals in the parent before
+ // vfork(), which will cause them to be blocked in the child as well (we
+ // rely on the fact that Linux, just like all sane implementations, only
+ // clones the calling thread). Then, in the child, we reset all signals
+ // to their default dispositions (while still blocked), and unblock them
+ // (so the exec()ed process inherits the parent's signal mask)
+ //
+ // The parent also unblocks all signals as soon as vfork() returns.
+ sigset_t allBlocked;
+ r = sigfillset(&allBlocked);
+ checkUnixError(r, "sigfillset");
+ sigset_t oldSignals;
+
+ r = pthread_sigmask(SIG_SETMASK, &allBlocked, &oldSignals);
+ checkPosixError(r, "pthread_sigmask");
+ SCOPE_EXIT {
+ // Restore signal mask
+ r = pthread_sigmask(SIG_SETMASK, &oldSignals, nullptr);
+ CHECK_EQ(r, 0) << "pthread_sigmask: " << errnoStr(r); // shouldn't fail
+ };
- // In parent
- checkUnixError(pid, "vfork");
- pid_ = pid;
- returnCode_ = ProcessReturnCode(RV_RUNNING);
+ // Call c_str() here, as it's not necessarily safe after fork.
+ const char* childDir =
+ options.childDir_.empty() ? nullptr : options.childDir_.c_str();
- // Parent work, post-fork: close child's ends of pipes
- for (int f : childFds) {
- closeChecked(f);
+ 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) {
+ childError(errFd, kChildFailure, errnoValue);
+ }
-namespace {
+ errnoValue = runChild(executable, argVec, envVec, options);
+ // If we get here, exec() failed.
+ childError(errFd, kExecFailure, errnoValue);
+ }
-// Checked version of close() to use in the child: abort() on error
-void childClose(int fd) {
- int r = ::close(fd);
- if (r == -1) abort();
+ // 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
+ // object will have never existed, and the destructor will never be called.
+ //
+ // We should only throw if we got an error via the errFd, and we know the
+ // 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::makeRunning();
}
-// Checked version of dup2() to use in the child: abort() on error
-void childDup2(int oldfd, int newfd) {
- int r = ::dup2(oldfd, newfd);
- if (r == -1) abort();
-}
+int Subprocess::prepareChild(const Options& options,
+ const sigset_t* sigmask,
+ const char* childDir) const {
+ // While all signals are blocked, we must reset their
+ // dispositions to default.
+ for (int sig = 1; sig < NSIG; ++sig) {
+ ::signal(sig, SIG_DFL);
+ }
-} // namespace
+ {
+ // Unblock signals; restore signal mask.
+ int r = pthread_sigmask(SIG_SETMASK, sigmask, nullptr);
+ if (r != 0) {
+ return r; // pthread_sigmask() returns an errno value
+ }
+ }
-void Subprocess::runChild(const char* executable,
- char** argv, char** env,
- const Options& options) const {
- // Close parent's ends of all pipes
- for (auto& p : pipes_) {
- childClose(p.parentFd);
+ // Change the working directory, if one is given
+ if (childDir) {
+ if (::chdir(childDir) == -1) {
+ return errno;
+ }
}
+ // We don't have to explicitly close the parent's end of all pipes,
+ // as they all have the FD_CLOEXEC flag set and will be closed at
+ // exec time.
+
// Close all fds that we're supposed to close.
- // Note that we're ignoring errors here, in case some of these
- // fds were set to close on exec.
for (auto& p : options.fdActions_) {
if (p.second == CLOSE) {
- ::close(p.first);
- } else {
- childDup2(p.second, p.first);
+ if (::close(p.first) == -1) {
+ return errno;
+ }
+ } else if (p.second != p.first) {
+ if (::dup2(p.second, p.first) == -1) {
+ return errno;
+ }
}
}
}
}
+#if __linux__
+ // Opt to receive signal on parent death, if requested
+ if (options.parentDeathSignal_ != 0) {
+ const auto parentDeathSignal =
+ static_cast<unsigned long>(options.parentDeathSignal_);
+ if (prctl(PR_SET_PDEATHSIG, parentDeathSignal, 0, 0, 0) == -1) {
+ return errno;
+ }
+ }
+#endif
+
+ if (options.processGroupLeader_) {
+ if (setpgrp() == -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;
+}
+
+int Subprocess::runChild(const char* executable,
+ char** argv, char** env,
+ const Options& options) const {
// Now, finally, exec.
- int r;
if (options.usePath_) {
::execvp(executable, argv);
} else {
::execve(executable, argv, env);
}
+ return errno;
+}
+
+void Subprocess::readChildErrorPipe(int pfd, const char* executable) {
+ ChildErrorInfo info;
+ auto rc = readNoInt(pfd, &info, sizeof(info));
+ if (rc == 0) {
+ // No data means the child executed successfully, and the pipe
+ // was closed due to the close-on-exec flag being set.
+ return;
+ } else if (rc != sizeof(ChildErrorInfo)) {
+ // An error occurred trying to read from the pipe, or we got a partial read.
+ // Neither of these cases should really occur in practice.
+ //
+ // We can't get any error data from the child in this case, and we don't
+ // know if it is successfully running or not. All we can do is to return
+ // normally, as if the child executed successfully. If something bad
+ // happened the caller should at least get a non-normal exit status from
+ // the child.
+ LOG(ERROR) << "unexpected error trying to read from child error pipe " <<
+ "rc=" << rc << ", errno=" << errno;
+ return;
+ }
+
+ // We got error data from the child. The child should exit immediately in
+ // this case, so wait on it to clean up.
+ wait();
- // If we're here, something's wrong.
- abort();
+ // Throw to signal the error
+ 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_;
returnCode_.enforce(ProcessReturnCode::RUNNING);
DCHECK_GT(pid_, 0);
int status;
- pid_t found = ::waitpid(pid_, &status, 0);
- checkUnixError(found, "waitpid");
- returnCode_ = ProcessReturnCode(status);
+ pid_t found;
+ do {
+ found = ::waitpid(pid_, &status, 0);
+ } while (found == -1 && errno == EINTR);
+ // 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::make(status);
+ pid_ = -1;
return returnCode_;
}
checkUnixError(r, "kill");
}
-namespace {
-void setNonBlocking(int fd) {
- int flags = ::fcntl(fd, F_GETFL);
- checkUnixError(flags, "fcntl");
- int r = ::fcntl(fd, F_SETFL, flags | O_NONBLOCK);
- checkUnixError(r, "fcntl");
+pid_t Subprocess::pid() const {
+ return pid_;
}
-std::pair<const uint8_t*, size_t> queueFront(const IOBufQueue& queue) {
+namespace {
+
+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;
- do {
- n = ::write(fd, p.first, p.second);
- } while (n == -1 && errno == EINTR);
+ ssize_t n = writeNoInt(fd, b.data(), b.size());
if (n == -1 && errno == EAGAIN) {
return false;
}
bool handleRead(int fd, IOBufQueue& queue) {
for (;;) {
auto p = queue.preallocate(100, 65000);
- ssize_t n;
- do {
- n = ::read(fd, p.first, p.second);
- } while (n == -1 && errno == EINTR);
+ ssize_t n = readNoInt(fd, p.first, p.second);
if (n == -1 && errno == EAGAIN) {
return false;
}
static std::unique_ptr<char[]> buf(new char[bufSize]);
for (;;) {
- ssize_t n;
- do {
- n = ::read(fd, buf.get(), bufSize);
- } while (n == -1 && errno == EINTR);
+ ssize_t n = readNoInt(fd, buf.get(), bufSize);
if (n == -1 && errno == EAGAIN) {
return false;
}
}
}
-} // namespace
+} // namespace
std::pair<std::string, std::string> Subprocess::communicate(
- int flags,
- StringPiece data) {
- IOBufQueue dataQueue;
- dataQueue.wrapBuffer(data.data(), data.size());
+ StringPiece input) {
+ IOBufQueue inputQueue;
+ inputQueue.wrapBuffer(input.data(), input.size());
- auto outQueues = communicateIOBuf(flags, std::move(dataQueue));
+ auto outQueues = communicateIOBuf(std::move(inputQueue));
auto outBufs = std::make_pair(outQueues.first.move(),
outQueues.second.move());
std::pair<std::string, std::string> out;
}
std::pair<IOBufQueue, IOBufQueue> Subprocess::communicateIOBuf(
- int flags,
- IOBufQueue data) {
+ IOBufQueue input) {
+ // If the user supplied a non-empty input buffer, make sure
+ // that stdin is a pipe so we can write the data.
+ if (!input.empty()) {
+ // findByChildFd() will throw std::invalid_argument if no pipe for
+ // STDIN_FILENO exists
+ findByChildFd(STDIN_FILENO);
+ }
+
std::pair<IOBufQueue, IOBufQueue> out;
- auto readCallback = [&, flags] (int pfd, int cfd) {
- if (cfd == 1 && (flags & READ_STDOUT)) {
+ auto readCallback = [&] (int pfd, int cfd) -> bool {
+ if (cfd == STDOUT_FILENO) {
return handleRead(pfd, out.first);
- } else if (cfd == 2 && (flags & READ_STDERR)) {
+ } else if (cfd == STDERR_FILENO) {
return handleRead(pfd, out.second);
} else {
// Don't close the file descriptor, the child might not like SIGPIPE,
}
};
- auto writeCallback = [&, flags] (int pfd, int cfd) {
- if (cfd == 0 && (flags & WRITE_STDIN)) {
- return handleWrite(pfd, data);
+ auto writeCallback = [&] (int pfd, int cfd) -> bool {
+ if (cfd == STDIN_FILENO) {
+ return handleWrite(pfd, input);
} else {
// If we don't want to write to this fd, just close it.
- return false;
+ return true;
}
};
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.
- pfd.events = (p.direction == PIPE_IN ? POLLOUT : POLLIN);
+ if (!p.enabled) {
+ // Still keeping fd in watched set so we get notified of POLLHUP /
+ // POLLERR
+ pfd.events = 0;
+ } else if (p.direction == PIPE_IN) {
+ pfd.events = POLLOUT;
+ } else {
+ pfd.events = POLLIN;
+ }
fds.push_back(pfd);
}
} while (r == -1 && errno == EINTR);
checkUnixError(r, "poll");
- for (int i = 0; i < pipes_.size(); ++i) {
+ 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;
}
}
- if (events & POLLIN) {
+ // Call read callback on POLLHUP, to give it a chance to read (and act
+ // 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);
}
}
}
-int Subprocess::findByChildFd(int childFd) const {
+void Subprocess::enableNotifications(int childFd, bool enabled) {
+ pipes_[findByChildFd(childFd)].enabled = enabled;
+}
+
+bool Subprocess::notificationsEnabled(int childFd) const {
+ return pipes_[findByChildFd(childFd)].enabled;
+}
+
+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 folly
+} // namespace
+} // namespace folly
projects / folly.git / blobdiff