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Add Coprocess class
It provides a convenient way to spawn a process and read from/write to its stdin/stdout.
1 parent 3db6271 commit 44f70e6

12 files changed

+992
-305
lines changed

‎Makefile

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,9 @@ OBJFILES = \
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gpg.o \
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key.o \
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util.o \
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parse_options.o
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parse_options.o \
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coprocess.o \
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fhstream.o
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OBJFILES += crypto-openssl.o
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LDFLAGS += -lcrypto

‎coprocess-unix.cpp

Lines changed: 186 additions & 0 deletions
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/*
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* Copyright 2015 Andrew Ayer
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*
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* This file is part of git-crypt.
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*
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* git-crypt is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* git-crypt is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with git-crypt. If not, see <http://www.gnu.org/licenses/>.
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*
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* Additional permission under GNU GPL version 3 section 7:
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*
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* If you modify the Program, or any covered work, by linking or
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* combining it with the OpenSSL project's OpenSSL library (or a
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* modified version of that library), containing parts covered by the
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* terms of the OpenSSL or SSLeay licenses, the licensors of the Program
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* grant you additional permission to convey the resulting work.
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* Corresponding Source for a non-source form of such a combination
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* shall include the source code for the parts of OpenSSL used as well
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* as that of the covered work.
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*/
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#include "coprocess.hpp"
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#include "util.hpp"
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <errno.h>
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static int execvp (const std::string& file, const std::vector<std::string>& args)
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{
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std::vector<const char*> args_c_str;
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args_c_str.reserve(args.size());
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for (std::vector<std::string>::const_iterator arg(args.begin()); arg != args.end(); ++arg) {
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args_c_str.push_back(arg->c_str());
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}
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args_c_str.push_back(NULL);
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return execvp(file.c_str(), const_cast<char**>(&args_c_str[0]));
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}
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Coprocess::Coprocess ()
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{
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pid = -1;
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stdin_pipe_reader = -1;
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stdin_pipe_writer = -1;
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stdin_pipe_ostream = NULL;
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stdout_pipe_reader = -1;
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stdout_pipe_writer = -1;
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stdout_pipe_istream = NULL;
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}
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Coprocess::~Coprocess ()
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{
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close_stdin();
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close_stdout();
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}
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std::ostream* Coprocess::stdin_pipe ()
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{
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if (!stdin_pipe_ostream) {
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int fds[2];
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if (pipe(fds) == -1) {
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throw System_error("pipe", "", errno);
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}
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stdin_pipe_reader = fds[0];
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stdin_pipe_writer = fds[1];
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stdin_pipe_ostream = new ofhstream(this, write_stdin);
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}
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return stdin_pipe_ostream;
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}
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void Coprocess::close_stdin ()
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{
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delete stdin_pipe_ostream;
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stdin_pipe_ostream = NULL;
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if (stdin_pipe_writer != -1) {
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close(stdin_pipe_writer);
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stdin_pipe_writer = -1;
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}
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if (stdin_pipe_reader != -1) {
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close(stdin_pipe_reader);
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stdin_pipe_reader = -1;
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}
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}
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std::istream* Coprocess::stdout_pipe ()
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{
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if (!stdout_pipe_istream) {
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int fds[2];
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if (pipe(fds) == -1) {
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throw System_error("pipe", "", errno);
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}
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stdout_pipe_reader = fds[0];
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stdout_pipe_writer = fds[1];
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stdout_pipe_istream = new ifhstream(this, read_stdout);
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}
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return stdout_pipe_istream;
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}
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void Coprocess::close_stdout ()
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{
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delete stdout_pipe_istream;
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stdout_pipe_istream = NULL;
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if (stdout_pipe_writer != -1) {
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close(stdout_pipe_writer);
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stdout_pipe_writer = -1;
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}
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if (stdout_pipe_reader != -1) {
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close(stdout_pipe_reader);
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stdout_pipe_reader = -1;
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}
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}
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void Coprocess::spawn (const std::vector<std::string>& args)
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{
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pid = fork();
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if (pid == -1) {
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throw System_error("fork", "", errno);
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}
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if (pid == 0) {
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if (stdin_pipe_writer != -1) {
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close(stdin_pipe_writer);
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}
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if (stdout_pipe_reader != -1) {
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close(stdout_pipe_reader);
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}
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if (stdin_pipe_reader != -1) {
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dup2(stdin_pipe_reader, 0);
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close(stdin_pipe_reader);
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}
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if (stdout_pipe_writer != -1) {
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dup2(stdout_pipe_writer, 1);
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close(stdout_pipe_writer);
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}
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execvp(args[0], args);
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perror(args[0].c_str());
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_exit(-1);
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}
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if (stdin_pipe_reader != -1) {
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close(stdin_pipe_reader);
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stdin_pipe_reader = -1;
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}
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if (stdout_pipe_writer != -1) {
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close(stdout_pipe_writer);
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stdout_pipe_writer = -1;
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}
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}
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int Coprocess::wait ()
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{
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int status = 0;
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if (waitpid(pid, &status, 0) == -1) {
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throw System_error("waitpid", "", errno);
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}
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return status;
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}
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size_t Coprocess::write_stdin (void* handle, const void* buf, size_t count)
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{
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const int fd = static_cast<Coprocess*>(handle)->stdin_pipe_writer;
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ssize_t ret;
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while ((ret = write(fd, buf, count)) == -1 && errno == EINTR); // restart if interrupted
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if (ret < 0) {
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throw System_error("write", "", errno);
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}
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return ret;
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}
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size_t Coprocess::read_stdout (void* handle, void* buf, size_t count)
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{
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const int fd = static_cast<Coprocess*>(handle)->stdout_pipe_reader;
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ssize_t ret;
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while ((ret = read(fd, buf, count)) == -1 && errno == EINTR); // restart if interrupted
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if (ret < 0) {
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throw System_error("read", "", errno);
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}
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return ret;
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}

‎coprocess-unix.hpp

Lines changed: 68 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,68 @@
1+
/*
2+
* Copyright 2015 Andrew Ayer
3+
*
4+
* This file is part of git-crypt.
5+
*
6+
* git-crypt is free software: you can redistribute it and/or modify
7+
* it under the terms of the GNU General Public License as published by
8+
* the Free Software Foundation, either version 3 of the License, or
9+
* (at your option) any later version.
10+
*
11+
* git-crypt is distributed in the hope that it will be useful,
12+
* but WITHOUT ANY WARRANTY; without even the implied warranty of
13+
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14+
* GNU General Public License for more details.
15+
*
16+
* You should have received a copy of the GNU General Public License
17+
* along with git-crypt. If not, see <http://www.gnu.org/licenses/>.
18+
*
19+
* Additional permission under GNU GPL version 3 section 7:
20+
*
21+
* If you modify the Program, or any covered work, by linking or
22+
* combining it with the OpenSSL project's OpenSSL library (or a
23+
* modified version of that library), containing parts covered by the
24+
* terms of the OpenSSL or SSLeay licenses, the licensors of the Program
25+
* grant you additional permission to convey the resulting work.
26+
* Corresponding Source for a non-source form of such a combination
27+
* shall include the source code for the parts of OpenSSL used as well
28+
* as that of the covered work.
29+
*/
30+
31+
#ifndef GIT_CRYPT_COPROCESS_HPP
32+
#define GIT_CRYPT_COPROCESS_HPP
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34+
#include "fhstream.hpp"
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#include <unistd.h>
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#include <vector>
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class Coprocess {
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pid_t pid;
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int stdin_pipe_reader;
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int stdin_pipe_writer;
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ofhstream* stdin_pipe_ostream;
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static size_t write_stdin (void*, const void*, size_t);
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int stdout_pipe_reader;
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int stdout_pipe_writer;
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ifhstream* stdout_pipe_istream;
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static size_t read_stdout (void*, void*, size_t);
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Coprocess (const Coprocess&); // Disallow copy
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Coprocess& operator= (const Coprocess&); // Disallow assignment
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public:
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Coprocess ();
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~Coprocess ();
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std::ostream* stdin_pipe ();
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void close_stdin ();
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std::istream* stdout_pipe ();
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void close_stdout ();
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void spawn (const std::vector<std::string>&);
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int wait ();
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};
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#endif

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