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cse3150-grading/includes/subprocess.hpp
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// | |
// subprocess C++ library - https://github.com/tsaarni/cpp-subprocess | |
// | |
// The MIT License (MIT) | |
// | |
// Copyright (c) 2015 Tero Saarni | |
// | |
#pragma once | |
#include <string> | |
#include <vector> | |
#include <iostream> | |
#include <ext/stdio_filebuf.h> | |
#include <cstdio> | |
#include <system_error> | |
#include <unistd.h> | |
#include <sys/types.h> | |
#include <sys/wait.h> | |
namespace subprocess | |
{ | |
class popen | |
{ | |
public: | |
popen(const std::string& cmd, std::vector<std::string> argv) | |
: in_filebuf(nullptr), out_filebuf(nullptr), err_filebuf(nullptr), in_stream(nullptr), out_stream(nullptr), err_stream(nullptr) | |
{ | |
if (pipe(in_pipe) == -1 || | |
pipe(out_pipe) == -1 || | |
pipe(err_pipe) == -1 ) | |
{ | |
throw std::system_error(errno, std::system_category()); | |
} | |
run(cmd, argv); | |
} | |
popen(const std::string& cmd, std::vector<std::string> argv, std::ostream& pipe_stdout) | |
: in_filebuf(nullptr), out_filebuf(nullptr), err_filebuf(nullptr), in_stream(nullptr), out_stream(nullptr), err_stream(nullptr) | |
{ | |
auto filebuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(pipe_stdout.rdbuf()); | |
out_pipe[READ] = -1; | |
out_pipe[WRITE] = filebuf->fd(); | |
if (pipe(in_pipe) == -1 || | |
pipe(err_pipe) == -1 ) | |
{ | |
throw std::system_error(errno, std::system_category()); | |
} | |
run(cmd, argv); | |
} | |
~popen() | |
{ | |
delete in_filebuf; | |
delete in_stream; | |
if (out_filebuf != nullptr) delete out_filebuf; | |
if (out_stream != nullptr) delete out_stream; | |
delete err_filebuf; | |
delete err_stream; | |
} | |
std::ostream& stdin() { return *in_stream; }; | |
std::istream& stdout() | |
{ | |
if (out_stream == nullptr) throw std::system_error(EBADF, std::system_category()); | |
return *out_stream; | |
}; | |
std::istream& stderr() { return *err_stream; }; | |
int wait() | |
{ | |
int status = 0; | |
waitpid(pid, &status, 0); | |
return WEXITSTATUS(status); | |
}; | |
void close() | |
{ | |
in_filebuf->close(); | |
} | |
private: | |
enum ends_of_pipe { READ = 0, WRITE = 1 }; | |
struct raii_char_str | |
{ | |
raii_char_str(std::string s) : buf(s.c_str(), s.c_str() + s.size() + 1) { }; | |
operator char*() const { return &buf[0]; }; | |
mutable std::vector<char> buf; | |
}; | |
void run(const std::string& cmd, std::vector<std::string> argv) | |
{ | |
argv.insert(argv.begin(), cmd); | |
pid = ::fork(); | |
if (pid == 0) child(argv); | |
::close(in_pipe[READ]); | |
::close(out_pipe[WRITE]); | |
::close(err_pipe[WRITE]); | |
in_filebuf = new __gnu_cxx::stdio_filebuf<char>(in_pipe[WRITE], std::ios_base::out, 1); | |
in_stream = new std::ostream(in_filebuf); | |
if (out_pipe[READ] != -1) | |
{ | |
out_filebuf = new __gnu_cxx::stdio_filebuf<char>(out_pipe[READ], std::ios_base::in, 1); | |
out_stream = new std::istream(out_filebuf); | |
} | |
err_filebuf = new __gnu_cxx::stdio_filebuf<char>(err_pipe[READ], std::ios_base::in, 1); | |
err_stream = new std::istream(err_filebuf); | |
} | |
void child(const std::vector<std::string>& argv) | |
{ | |
if (dup2(in_pipe[READ], STDIN_FILENO) == -1 || | |
dup2(out_pipe[WRITE], STDOUT_FILENO) == -1 || | |
dup2(err_pipe[WRITE], STDERR_FILENO) == -1 ) | |
{ | |
std::perror("subprocess: dup2() failed"); | |
return; | |
} | |
::close(in_pipe[READ]); | |
::close(in_pipe[WRITE]); | |
if (out_pipe[READ] != -1) ::close(out_pipe[READ]); | |
::close(out_pipe[WRITE]); | |
::close(err_pipe[READ]); | |
::close(err_pipe[WRITE]); | |
std::vector<raii_char_str> real_args(argv.begin(), argv.end()); | |
std::vector<char*> cargs(real_args.begin(), real_args.end()); | |
cargs.push_back(nullptr); | |
if (execvp(cargs[0], &cargs[0]) == -1) | |
{ | |
std::perror("subprocess: execvp() failed"); | |
return; | |
} | |
} | |
pid_t pid; | |
int in_pipe[2]; | |
int out_pipe[2]; | |
int err_pipe[2]; | |
__gnu_cxx::stdio_filebuf<char>* in_filebuf; | |
__gnu_cxx::stdio_filebuf<char>* out_filebuf; | |
__gnu_cxx::stdio_filebuf<char>* err_filebuf; | |
std::ostream* in_stream; | |
std::istream* out_stream; | |
std::istream* err_stream; | |
}; | |
} // namespace: subprocess |