681 lines
18 KiB
C++
681 lines
18 KiB
C++
/* Process handling implementation bits.
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*
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* This file is part of libostd. See COPYING.md for futher information.
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*/
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#include <cstddef>
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#include <cstdlib>
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#include <cerrno>
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#include <system_error>
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#include <string>
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#include <memory>
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#include <new>
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#include "ostd/process.hh"
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#include "ostd/format.hh"
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#include <fcntl.h>
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#ifdef OSTD_PLATFORM_WIN32
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# include "ostd/filesystem.hh"
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# include <windows.h>
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namespace fs = ostd::filesystem;
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#else
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# include <unistd.h>
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# include <sys/wait.h>
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# include <wordexp.h>
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#endif
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namespace ostd {
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namespace detail {
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OSTD_EXPORT void split_args_impl(
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string_range const &str, void (*func)(string_range, void *), void *data
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) {
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if (!str.size()) {
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return;
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}
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#ifndef OSTD_PLATFORM_WIN32
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std::string strs{str};
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wordexp_t p;
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if (int err; (err = wordexp(strs.data(), &p, 0))) {
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switch (err) {
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case WRDE_BADCHAR:
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throw word_error{"illegal character"};
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case WRDE_BADVAL:
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/* no WRDE_UNDEF flag, won't happen */
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throw word_error{"undefined shell variable"};
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case WRDE_CMDSUB:
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/* no WRDE_NOCMD flag, won't happen */
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throw word_error{"invalid command substitution"};
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case WRDE_NOSPACE:
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throw std::bad_alloc{};
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case WRDE_SYNTAX:
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throw word_error{"syntax error"};
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default:
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throw word_error{"unknown error"};
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}
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}
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/* if the output range throws, make sure stuff gets freed */
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struct wordexp_guard {
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void operator()(wordexp_t *fp) const {
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wordfree(fp);
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}
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};
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std::unique_ptr<wordexp_t, wordexp_guard> guard{&p};
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for (std::size_t i = 0; i < p.we_wordc; ++i) {
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func(p.we_wordv[i], data);
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}
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#else
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std::unique_ptr<wchar_t[]> wstr{new wchar_t[str.size() + 1]};
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memset(wstr.get(), 0, (str.size() + 1) * sizeof(wchar_t));
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if (!MultiByteToWideChar(
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CP_UTF8, 0, str.data(), str.size(), wstr.get(), str.size() + 1
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)) {
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throw word_error{"unicode conversion failed"};
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}
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int argc = 0;
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wchar_t **pwargs = CommandLineToArgvW(wstr.get(), &argc);
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if (!pwargs) {
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throw word_error{"command line parsing failed"};
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}
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/* if anything throws, make sure stuff gets freed */
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struct wchar_guard {
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void operator()(wchar_t **p) const {
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LocalFree(p);
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}
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};
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std::unique_ptr<wchar_t *, wchar_guard> wguard{pwargs};
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for (int i = 0; i < argc; ++i) {
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wchar_t *arg = pwargs[i];
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std::size_t arglen = wcslen(arg);
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std::size_t req = 0;
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if (!(req = WideCharToMultiByte(
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CP_UTF8, 0, arg, arglen + 1, nullptr, 0, nullptr, nullptr
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))) {
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throw word_error{"unicode conversion failed"};
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}
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std::unique_ptr<char[]> buf{new char[req]};
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if (!WideCharToMultiByte(
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CP_UTF8, 0, arg, arglen + 1, buf.get(), req, nullptr, nullptr
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)) {
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throw word_error{"unicode conversion failed"};
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}
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func(string_range{buf.get(), buf.get() + req - 1}, data);
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}
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#endif
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}
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} /* namespace detail */
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#ifndef OSTD_PLATFORM_WIN32
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struct data {
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int pid = -1, errno_fd = -1;
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};
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struct pipe {
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int fd[2] = { -1, -1 };
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~pipe() {
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if (fd[0] >= 0) {
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::close(fd[0]);
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}
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if (fd[1] >= 0) {
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::close(fd[1]);
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}
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}
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void open(process_stream use) {
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if (use != process_stream::PIPE) {
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return;
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}
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if (::pipe(fd) < 0) {
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throw process_error{"could not open pipe"};
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}
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}
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int &operator[](std::size_t idx) {
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return fd[idx];
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}
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void fdopen(file_stream &s, bool write) {
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FILE *p = ::fdopen(fd[std::size_t(write)], write ? "w" : "r");
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if (!p) {
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throw process_error{"could not open redirected stream"};
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}
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/* do not close twice, the stream will close it */
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fd[std::size_t(write)] = -1;
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s.open(p, [](FILE *f) {
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std::fclose(f);
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});
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}
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void close(bool write) {
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::close(std::exchange(fd[std::size_t(write)], -1));
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}
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bool dup2(int target, pipe &err, bool write) {
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if (::dup2(fd[std::size_t(write)], target) < 0) {
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err.write_errno();
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return false;
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}
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close(write);
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return true;
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}
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void write_errno() {
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write(fd[1], int(errno), sizeof(int));
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}
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};
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OSTD_EXPORT void subprocess::open_impl(
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std::string const &cmd, std::vector<std::string> const &args,
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bool use_path
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) {
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if (use_in == process_stream::STDOUT) {
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throw process_error{"could not redirect stdin to stdout"};
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}
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auto argp = std::make_unique<char *[]>(args.size() + 1);
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for (std::size_t i = 0; i < args.size(); ++i) {
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argp[i] = const_cast<char *>(args[i].data());
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}
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argp[args.size()] = nullptr;
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/* fd_errno used to detect if exec failed */
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pipe fd_errno, fd_stdin, fd_stdout, fd_stderr;
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fd_errno.open(process_stream::PIPE);
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fd_stdin.open(use_in);
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fd_stdout.open(use_out);
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fd_stderr.open(use_err);
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auto cpid = fork();
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if (cpid == -1) {
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throw process_error{"fork failed"};
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} else if (!cpid) {
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/* child process */
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fd_errno.close(false);
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/* fcntl fails, write the errno to be read from parent */
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if (fcntl(fd_errno[1], F_SETFD, FD_CLOEXEC) < 0) {
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fd_errno.write_errno();
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std::exit(1);
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}
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/* prepare standard streams */
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if (use_in == process_stream::PIPE) {
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fd_stdin.close(true);
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if (!fd_stdin.dup2(STDIN_FILENO, fd_errno, false)) {
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std::exit(1);
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}
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}
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if (use_out == process_stream::PIPE) {
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fd_stdout.close(false);
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if (!fd_stdout.dup2(STDOUT_FILENO, fd_errno, true)) {
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std::exit(1);
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}
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}
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if (use_err == process_stream::PIPE) {
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fd_stderr.close(false);
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if (!fd_stderr.dup2(STDERR_FILENO, fd_errno, true)) {
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std::exit(1);
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}
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} else if (use_err == process_stream::STDOUT) {
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if (dup2(STDOUT_FILENO, STDERR_FILENO) < 0) {
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fd_errno.write_errno();
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std::exit(1);
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}
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}
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if (use_path) {
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execvp(cmd.data(), argp.get());
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} else {
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execv(cmd.data(), argp.get());
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}
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/* exec has returned, so error has occured */
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fd_errno.write_errno();
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std::exit(1);
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} else {
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/* parent process */
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fd_errno.close(true);
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if (use_in == process_stream::PIPE) {
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fd_stdin.close(false);
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fd_stdin.fdopen(in, true);
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}
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if (use_out == process_stream::PIPE) {
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fd_stdout.close(true);
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fd_stdout.fdopen(out, false);
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}
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if (use_err == process_stream::PIPE) {
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fd_stderr.close(true);
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fd_stderr.fdopen(err, false);
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}
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p_current = ::new (reinterpret_cast<void *>(&p_data)) data{
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int(cpid), std::exchange(fd_errno[1], -1)
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};
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}
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}
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OSTD_EXPORT void subprocess::reset() {
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if (!p_current) {
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return;
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}
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data *pd = static_cast<data *>(p_current);
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if (pd->errno_fd >= 0) {
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::close(pd->errno_fd);
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}
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p_current = nullptr;
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}
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OSTD_EXPORT int subprocess::close() {
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if (!p_current) {
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throw process_error{"no child process"};
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}
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data *pd = static_cast<data *>(p_current);
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int retc = 0;
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if (pid_t wp; (wp = waitpid(pd->pid, &retc, 0)) < 0) {
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reset();
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throw process_error{"child process wait failed"};
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}
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if (retc) {
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int eno;
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auto r = read(pd->errno_fd, &eno, sizeof(int));
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reset();
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if (r < 0) {
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throw process_error{"could not read from pipe"};
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} else if (r == sizeof(int)) {
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auto ec = std::system_category().default_error_condition(eno);
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auto app = appender<std::string>();
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format(app, "could not execute subprocess (%s)", ec.message());
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throw process_error{std::move(app.get())};
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}
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}
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reset();
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return retc;
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}
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#else /* OSTD_PLATFORM_WIN32 */
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struct data {
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HANDLE process = nullptr, thread = nullptr;
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};
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struct pipe {
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HANDLE p_r = nullptr, p_w = nullptr;
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~pipe() {
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if (p_r) {
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CloseHandle(p_r);
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}
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if (p_w) {
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CloseHandle(p_w);
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}
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}
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void open(process_stream use, SECURITY_ATTRIBUTES &sa, bool read) {
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if (use != process_stream::PIPE) {
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return;
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}
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if (!CreatePipe(&p_r, &p_w, &sa, 0)) {
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throw process_error{"could not open pipe"};
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}
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if (!SetHandleInformation(read ? p_r : p_w, HANDLE_FLAG_INHERIT, 0)) {
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throw process_error{"could not set pipe parameters"};
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}
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}
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void fdopen(file_stream &s, bool read) {
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int fd = _open_osfhandle(
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reinterpret_cast<intptr_t>(read ? p_r : p_w),
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read ? _O_RDONLY : 0
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);
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if (fd < 0) {
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throw process_error{"could not open redirected stream"};
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}
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if (read) {
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p_r = nullptr;
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} else {
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p_w = nullptr;
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}
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auto p = _fdopen(fd, read ? "r" : "w");
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if (!p) {
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_close(fd);
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throw process_error{"could not open redirected stream"};
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}
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s.open(p, [](FILE *f) {
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std::fclose(f);
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});
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}
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};
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/* because there is no way to have CreateProcess do a lookup in standard
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* paths AND specify a custom separate argv[0], we need to implement the
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* path resolution ourselves; fortunately the standard filesystem API
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* makes this kind of easy, but it's still a lot of code I'd rather
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* not write... oh well
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*/
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static std::wstring resolve_file(wchar_t const *cmd) {
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/* a reused buffer, TODO: allow longer paths */
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wchar_t buf[1024];
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auto is_maybe_exec = [](fs::path const &p) {
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auto st = fs::status(p);
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return (fs::is_regular_file(st) || fs::is_symlink(st));
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};
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fs::path p{cmd};
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/* deal with some easy cases */
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if ((p.filename() != p) || (p == L".") || (p == L"..")) {
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return cmd;
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}
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/* no extension appends .exe as is done normally */
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if (!p.has_extension()) {
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p.replace_extension(L".exe");
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}
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/* the directory from which the app loaded */
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if (GetModuleFileNameW(nullptr, buf, sizeof(buf))) {
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fs::path rp{buf};
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rp.replace_filename(p);
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if (is_maybe_exec(rp)) {
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return rp.native();
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}
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}
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/* the current directory */
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{
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auto rp = fs::path{L"."} / p;
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if (is_maybe_exec(rp)) {
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return rp.native();
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}
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}
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/* the system directory */
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if (GetSystemDirectoryW(buf, sizeof(buf))) {
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auto rp = fs::path{buf} / p;
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if (is_maybe_exec(rp)) {
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return rp.native();
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}
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}
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/* the windows directory */
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if (GetWindowsDirectoryW(buf, sizeof(buf))) {
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auto rp = fs::path{buf} / p;
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if (is_maybe_exec(rp)) {
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return rp.native();
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}
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}
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/* the PATH envvar */
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std::size_t req = GetEnvironmentVariableW(L"PATH", buf, sizeof(buf));
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if (req) {
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wchar_t *envp = buf;
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std::vector<wchar_t> dynbuf;
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if (req > sizeof(buf)) {
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dynbuf.reserve(req);
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for (;;) {
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req = GetEnvironmentVariableW(
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L"PATH", dynbuf.data(), dynbuf.capacity()
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);
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if (!req) {
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return cmd;
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}
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if (req > dynbuf.capacity()) {
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dynbuf.reserve(req);
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} else {
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envp = dynbuf.data();
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break;
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}
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}
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}
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for (;;) {
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auto sp = wcschr(envp, L';');
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fs::path rp;
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if (!sp) {
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rp = fs::path{envp} / p;
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} else if (sp == envp) {
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envp = sp + 1;
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continue;
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} else {
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rp = fs::path{envp, sp} / p;
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envp = sp + 1;
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}
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if (is_maybe_exec(rp)) {
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return rp.native();
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}
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}
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}
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/* nothing found */
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return cmd;
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}
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/* windows follows a dumb set of rules for parsing command line params;
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* a single \ is normally interpreted literally, unless it precedes a ",
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* in which case it acts as an escape character for the quotation mark;
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* if multiple backslashes precedes the quotation mark, each pair is
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* treated as a single backslash
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*
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* we need to replicate this awful behavior here, hence the extra code
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*/
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static std::string concat_args(std::vector<std::string> const &args) {
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std::string ret;
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for (auto &s: args) {
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if (!ret.empty()) {
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ret += ' ';
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}
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ret += '\"';
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for (char const *sp = s.data();;) {
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char const *p = strpbrk(sp, "\"\\");
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if (!p) {
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ret += sp;
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break;
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}
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ret.append(sp, p);
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if (*p == '\"') {
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/* not preceded by \, so it's safe */
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ret += "\\\"";
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} else {
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/* handle any sequence of \ optionally followed by a " */
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std::size_t nbsl = 0;
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while (*p++ == '\\') {
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++nbsl;
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}
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if (*p == '\"') {
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/* double all the backslashes plus one for the " */
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ret.append(nbsl * 2 + 1, '\\');
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ret += '\"';
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} else {
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ret.append(nbsl, '\\');
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}
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}
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sp = p + 1;
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}
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ret += '\"';
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}
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return ret;
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}
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OSTD_EXPORT void subprocess::open_impl(
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std::string const &cmd, std::vector<std::string> const &args, bool use_path
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) {
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if (use_in == process_stream::STDOUT) {
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throw process_error{"could not redirect stdin to stdout"};
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}
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/* pipes */
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SECURITY_ATTRIBUTES sa;
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sa.nLength = sizeof(SECURITY_ATTRIBUTES);
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sa.bInheritHandle = true;
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sa.lpSecurityDescriptor = nullptr;
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pipe pipe_in, pipe_out, pipe_err;
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pipe_in.open(use_in, sa, false);
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pipe_out.open(use_out, sa, true);
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pipe_err.open(use_err, sa, true);
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/* process creation */
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PROCESS_INFORMATION pi;
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STARTUPINFOW si;
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memset(&pi, 0, sizeof(PROCESS_INFORMATION));
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memset(&si, 0, sizeof(STARTUPINFOW));
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si.cb = sizeof(STARTUPINFOW);
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if (use_in == process_stream::PIPE) {
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si.hStdInput = pipe_in.p_r;
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pipe_in.fdopen(in, false);
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} else {
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si.hStdInput = GetStdHandle(STD_INPUT_HANDLE);
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if (si.hStdInput == INVALID_HANDLE_VALUE) {
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throw process_error{"could not get standard input handle"};
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}
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}
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|
if (use_out == process_stream::PIPE) {
|
|
si.hStdOutput = pipe_out.p_w;
|
|
pipe_out.fdopen(out, true);
|
|
} else {
|
|
si.hStdOutput = GetStdHandle(STD_OUTPUT_HANDLE);
|
|
if (si.hStdOutput == INVALID_HANDLE_VALUE) {
|
|
throw process_error{"could not get standard output handle"};
|
|
}
|
|
}
|
|
if (use_err == process_stream::PIPE) {
|
|
si.hStdError = pipe_err.p_w;
|
|
pipe_err.fdopen(err, true);
|
|
} else if (use_err == process_stream::STDOUT) {
|
|
si.hStdError = si.hStdOutput;
|
|
} else {
|
|
si.hStdError = GetStdHandle(STD_ERROR_HANDLE);
|
|
if (si.hStdError == INVALID_HANDLE_VALUE) {
|
|
throw process_error{"could not get standard error handle"};
|
|
}
|
|
}
|
|
si.dwFlags |= STARTF_USESTDHANDLES;
|
|
|
|
std::wstring cmdpath;
|
|
/* convert and optionally resolve PATH and other lookup locations */
|
|
{
|
|
std::unique_ptr<wchar_t[]> wcmd{new wchar_t[cmd.size() + 1]};
|
|
if (!MultiByteToWideChar(
|
|
CP_UTF8, 0, cmd.data(), cmd.size() + 1, wcmd.get(), cmd.size() + 1
|
|
)) {
|
|
throw process_error{"unicode conversion failed"};
|
|
}
|
|
if (use_path) {
|
|
cmdpath = wcmd.get();
|
|
} else {
|
|
cmdpath = resolve_file(wcmd.get());
|
|
}
|
|
}
|
|
|
|
/* cmdline gets an ordinary conversion... */
|
|
auto astr = concat_args(args);
|
|
|
|
std::unique_ptr<wchar_t[]> cmdline{new wchar_t[astr.size() + 1]};
|
|
if (!MultiByteToWideChar(
|
|
CP_UTF8, 0, astr.data(), astr.size() + 1, cmdline.get(), astr.size() + 1
|
|
)) {
|
|
throw process_error{"unicode conversion failed"};
|
|
}
|
|
|
|
/* owned by CreateProcess, do not close explicitly */
|
|
pipe_in.p_r = nullptr;
|
|
pipe_out.p_w = nullptr;
|
|
pipe_err.p_w = nullptr;
|
|
|
|
auto success = CreateProcessW(
|
|
cmdpath.data(),
|
|
cmdline.get(),
|
|
nullptr, /* process security attributes */
|
|
nullptr, /* primary thread security attributes */
|
|
true, /* inherit handles */
|
|
0, /* creation flags */
|
|
nullptr, /* use parent env */
|
|
nullptr, /* use parent cwd */
|
|
&si,
|
|
&pi
|
|
);
|
|
|
|
p_current = ::new (reinterpret_cast<void *>(&p_data)) data{
|
|
pi.hProcess, pi.hThread
|
|
};
|
|
|
|
if (!success) {
|
|
throw process_error{"could not execute subprocess"};
|
|
}
|
|
}
|
|
|
|
OSTD_EXPORT void subprocess::reset() {
|
|
p_current = nullptr;
|
|
}
|
|
|
|
OSTD_EXPORT int subprocess::close() {
|
|
if (!p_current) {
|
|
throw process_error{"no child process"};
|
|
}
|
|
|
|
data *pd = static_cast<data *>(p_current);
|
|
|
|
if (WaitForSingleObject(pd->process, INFINITE) == WAIT_FAILED) {
|
|
CloseHandle(pd->process);
|
|
CloseHandle(pd->thread);
|
|
reset();
|
|
throw process_error{"child process wait failed"};
|
|
}
|
|
|
|
DWORD ec = 0;
|
|
if (!GetExitCodeProcess(pd->process, &ec)) {
|
|
CloseHandle(pd->process);
|
|
CloseHandle(pd->thread);
|
|
reset();
|
|
throw process_error{"could not retrieve exit code"};
|
|
}
|
|
|
|
CloseHandle(pd->process);
|
|
CloseHandle(pd->thread);
|
|
reset();
|
|
|
|
return int(ec);
|
|
}
|
|
|
|
#endif
|
|
|
|
OSTD_EXPORT void subprocess::move_data(subprocess &i) {
|
|
data *od = static_cast<data *>(i.p_current);
|
|
if (!od) {
|
|
return;
|
|
}
|
|
p_current = ::new (reinterpret_cast<void *>(&p_data)) data{*od};
|
|
i.p_current = nullptr;
|
|
}
|
|
|
|
OSTD_EXPORT void subprocess::swap_data(subprocess &i) {
|
|
if (!p_current) {
|
|
move_data(i);
|
|
} else if (!i.p_current) {
|
|
i.move_data(*this);
|
|
} else {
|
|
std::swap(
|
|
*static_cast<data *>(p_current), *static_cast<data *>(i.p_current)
|
|
);
|
|
}
|
|
}
|
|
|
|
OSTD_EXPORT subprocess::~subprocess() {
|
|
try {
|
|
close();
|
|
} catch (process_error const &) {}
|
|
reset();
|
|
}
|
|
|
|
} /* namespace ostd */
|