/*
- * Copyright 2014 Facebook, Inc.
+ * Copyright 2016 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 <folly/Conv.h>
#include <folly/Exception.h>
-#include <folly/FileUtil.h>
#include <folly/ScopeGuard.h>
+#include <folly/Shell.h>
#include <folly/String.h>
#include <folly/io/Cursor.h>
-
-extern char** environ;
+#include <folly/portability/Environment.h>
+#include <folly/portability/Sockets.h>
+#include <folly/portability/Unistd.h>
constexpr int kExecFailure = 127;
constexpr int kChildFailure = 126;
namespace folly {
+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;
(coreDumped() ? " (core dumped)" : ""));
}
CHECK(false); // unreached
+ return ""; // silence GCC warning
}
CalledProcessError::CalledProcessError(ProcessReturnCode rc)
// 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 *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");
}
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.
} // namespace
-void Subprocess::closeAll() {
- for (auto& p : pipes_) {
- closeChecked(p.parentFd);
- }
- pipes_.clear();
-}
-
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()
int errFds[2];
#if FOLLY_HAVE_PIPE2
- int r = ::pipe2(errFds, O_CLOEXEC);
+ checkUnixError(::pipe2(errFds, O_CLOEXEC), "pipe2");
#else
- int r = ::pipe(errFds);
+ checkUnixError(::pipe(errFds), "pipe");
#endif
- checkUnixError(r, "pipe");
SCOPE_EXIT {
CHECK_ERR(::close(errFds[0]));
if (errFds[1] >= 0) {
CHECK_ERR(::close(errFds[1]));
}
};
- // Ask the child to close the read end of the error pipe.
- options.fdActions_[errFds[0]] = CLOSE;
#if !FOLLY_HAVE_PIPE2
- r = fcntl(errFds[0], F_SETFD, FD_CLOEXEC);
- checkUnixError(r, "set FD_CLOEXEC");
+ // 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.
- r = fcntl(errFds[1], F_SETFD, FD_CLOEXEC);
- checkUnixError(r, "set FD_CLOEXEC");
+ checkUnixError(fcntl(errFds[1], F_SETFD, FD_CLOEXEC), "set FD_CLOEXEC");
#endif
// Perform the actual work of setting up pipes then forking and
// 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], /*owns_fd=*/ true);
cfd = fds[0];
} else {
- pinfo.parentFd = fds[0];
+ pipe.pipe = folly::File(fds[0], /*owns_fd=*/ 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);
}
}
}
}
- // Close parent's ends of all pipes
- for (auto& p : pipes_) {
- if (::close(p.parentFd) == -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.
for (auto& p : options.fdActions_) {
#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;
}
}
#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;
}
char** argv, char** env,
const Options& options) const {
// Now, finally, exec.
- int r;
if (options.usePath_) {
::execvp(executable, argv);
} else {
DCHECK_GT(pid_, 0);
int status;
pid_t found = ::waitpid(pid_, &status, WNOHANG);
- checkUnixError(found, "waitpid");
+ // 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) {
+ // Though the child process had quit, this call does not close the pipes
+ // since its descendants may still be using them.
returnCode_ = ProcessReturnCode(status);
pid_ = -1;
}
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);
pid_ = -1;
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;
}
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) {
} 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;
}
// 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 {
} // namespace
} // namespace folly
-
projects / folly.git / blobdiff