Commit 405aa948 authored by Steffen Vogel's avatar Steffen Vogel 🎅🏼

popen: added iostream-based bidirectional popen()

parent 001966f8
/** Bi-directional popen
*
* @file
* @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
* @copyright 2014-2019, Institute for Automation of Complex Power Systems, EONERC
* @license GNU General Public License (version 3)
*
* VILLAScommon
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************************/
#pragma once
#include <signal.h>
#include <ext/stdio_filebuf.h>
#include <string>
#include <istream>
#include <ostream>
#include <memory>
namespace villas {
namespace utils {
class Popen {
public:
using char_type = char;
using stdio_buf = __gnu_cxx::stdio_filebuf<char_type>;
Popen(const std::string &command);
~Popen();
void open();
int close();
void kill(int signal = SIGINT);
std::istream &in()
{
return *(input.stream);
}
std::ostream &out()
{
return *(output.stream);
}
protected:
std::string command;
pid_t pid;
struct {
std::unique_ptr<std::istream> stream;
std::unique_ptr<stdio_buf> buffer;
} input;
struct {
std::unique_ptr<std::ostream> stream;
std::unique_ptr<stdio_buf> buffer;
} output;
};
} /* namespace utils */
} /* namespace villas */
template<typename T>
std::istream& operator>>(villas::utils::Popen& po, T& value)
{
return *(po.input.stream) >> value;
}
......@@ -46,6 +46,7 @@ add_library(villas-common SHARED
common.cpp
tool.cpp
base64.cpp
popen.cpp
)
execute_process(
......
/** Bi-directional popen
*
* @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
* @copyright 2014-2019, Institute for Automation of Complex Power Systems, EONERC
* @license GNU General Public License (version 3)
*
* VILLAScommon
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************************/
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <signal.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <paths.h>
#include <dirent.h>
#include <villas/exceptions.hpp>
#include <villas/popen.hpp>
namespace villas {
namespace utils {
Popen::Popen(const std::string &cmd) :
command(cmd)
{
open();
}
Popen::~Popen()
{
close();
}
void Popen::kill(int signal)
{
::kill(pid, signal);
}
void Popen::open()
{
const int READ = 0;
const int WRITE = 1;
int ret;
int inpipe[2];
int outpipe[2];
char *argv[4];
ret = pipe(inpipe);
if (ret)
goto error_out;
ret = pipe(outpipe);
if (ret)
goto clean_inpipe_out;
input.buffer = std::make_unique<stdio_buf>(outpipe[READ], std::ios_base::in);
output.buffer = std::make_unique<stdio_buf>(inpipe[WRITE], std::ios_base::out);
input.stream = std::make_unique<std::istream>(input.buffer.get());
output.stream = std::make_unique<std::ostream>(output.buffer.get());
pid = fork();
if (pid == -1)
goto clean_outpipe_out;
if (pid == 0) {
::close(outpipe[READ]);
::close(inpipe[WRITE]);
if (inpipe[READ] != STDIN_FILENO) {
dup2(inpipe[READ], STDIN_FILENO);
::close(inpipe[READ]);
}
if (outpipe[WRITE] != STDOUT_FILENO) {
dup2(outpipe[WRITE], STDOUT_FILENO);
::close(outpipe[WRITE]);
}
argv[0] = (char *) "sh";
argv[1] = (char *) "-c";
argv[2] = (char *) command.c_str();
argv[3] = nullptr;
execv(_PATH_BSHELL, (char * const *) argv);
exit(127);
}
::close(outpipe[WRITE]);
::close(inpipe[READ]);
return;
clean_outpipe_out:
::close(outpipe[READ]);
::close(outpipe[WRITE]);
clean_inpipe_out:
::close(inpipe[READ]);
::close(inpipe[WRITE]);
error_out:
throw SystemError("Failed to start subprocess");
}
int Popen::close()
{
int pstat;
if (pid != -1) {
do {
pid = waitpid(pid, &pstat, 0);
} while (pid == -1 && errno == EINTR);
}
input.stream.reset();
output.stream.reset();
input.buffer.reset();
output.buffer.reset();
return pid == -1 ? -1 : pstat;
}
} /* namespace utils */
} /* namespace villas */
......@@ -31,6 +31,7 @@ add_executable(unit-tests-common
timing.cpp
utils.cpp
base64.cpp
popen.cpp
)
if(ARCH STREQUAL "x86_64")
......
/** Unit tests for bi-directional popen
*
* @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
* @copyright 2014-2019, Institute for Automation of Complex Power Systems, EONERC
* @license GNU General Public License (version 3)
*
* VILLAScommon
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************************/
#include <iostream>
#include <criterion/criterion.h>
#include <villas/popen.hpp>
using namespace villas::utils;
TestSuite(popen, .description = "Bi-directional popen");
Test(popen, cat)
{
Popen proc("cat");
proc.out() << "Hello World" << std::endl;
proc.out().flush();
std::string str, str2;
proc.in() >> str >> str2;
cr_assert_eq(str, "Hello");
cr_assert_eq(str2, "World");
proc.kill();
proc.close();
}
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment