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/* 2019, MariaDB Corporation.
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; version 2 of the License.
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, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/*
Replacement of the buggy implementations of popen in Windows CRT
*/
#include <windows.h>
#include <fcntl.h>
#include <io.h>
#include <mutex>
#include <stdlib.h>
#include <unordered_map>
enum
{
REDIRECT_STDIN= 'w',
REDIRECT_STDOUT= 'r'
};
/** Map from FILE* returned by popen() to corresponding process handle.*/
static std::unordered_map<FILE *, HANDLE> popen_map;
/* Mutex to protect the map.*/
static std::mutex popen_mtx;
/**
Creates a FILE* from HANDLE.
*/
static FILE *make_fp(HANDLE *handle, const char *mode)
{
int flags = 0;
if (mode[0] == REDIRECT_STDOUT)
flags |= O_RDONLY;
switch (mode[1])
{
case 't':
flags |= _O_TEXT;
break;
case 'b':
flags |= _O_BINARY;
break;
}
int fd= _open_osfhandle((intptr_t) *handle, flags);
if (fd < 0)
return NULL;
FILE *fp= fdopen(fd, mode);
if (!fp)
{
/* Closing file descriptor also closes underlying handle.*/
close(fd);
*handle= 0;
}
return fp;
}
/** A home-backed version of popen(). */
extern "C" FILE *my_win_popen(const char *cmd, const char *mode)
{
FILE *fp(0);
char type= mode[0];
HANDLE parent_pipe_end(0);
HANDLE child_pipe_end(0);
PROCESS_INFORMATION pi{};
STARTUPINFO si{};
std::string command_line;
/* Create a pipe between this and child process.*/
SECURITY_ATTRIBUTES sa_attr{};
sa_attr.nLength= sizeof(SECURITY_ATTRIBUTES);
sa_attr.bInheritHandle= TRUE;
switch (type)
{
case REDIRECT_STDIN:
if (!CreatePipe(&child_pipe_end, &parent_pipe_end, &sa_attr, 0))
goto error;
break;
case REDIRECT_STDOUT:
if (!CreatePipe(&parent_pipe_end, &child_pipe_end, &sa_attr, 0))
goto error;
break;
default:
/* Unknown mode, expected "r", "rt", "w", "wt" */
abort();
}
if (!SetHandleInformation(parent_pipe_end, HANDLE_FLAG_INHERIT, 0))
goto error;
/* Start child process with redirected output.*/
si.cb= sizeof(STARTUPINFO);
si.hStdError= GetStdHandle(STD_ERROR_HANDLE);
si.hStdOutput= (type == REDIRECT_STDOUT) ? child_pipe_end
: GetStdHandle(STD_OUTPUT_HANDLE);
si.hStdInput= (type == REDIRECT_STDIN) ? child_pipe_end
: GetStdHandle(STD_INPUT_HANDLE);
si.dwFlags|= STARTF_USESTDHANDLES;
command_line.append("cmd.exe /c ").append(cmd);
if (!CreateProcess(0, (LPSTR) command_line.c_str(), 0, 0, TRUE, 0, 0, 0, &si,
&pi))
goto error;
CloseHandle(pi.hThread);
CloseHandle(child_pipe_end);
child_pipe_end= 0;
fp= make_fp(&parent_pipe_end, mode);
if (fp)
{
std::unique_lock<std::mutex> lk(popen_mtx);
popen_map[fp]= pi.hProcess;
return fp;
}
error:
for (auto handle : { parent_pipe_end, child_pipe_end })
{
if (handle)
CloseHandle(handle);
}
if (pi.hProcess)
{
TerminateProcess(pi.hProcess, 1);
CloseHandle(pi.hProcess);
}
return NULL;
}
/** A home-backed version of pclose(). */
extern "C" int my_win_pclose(FILE *fp)
{
/* Find process entry for given file pointer.*/
std::unique_lock<std::mutex> lk(popen_mtx);
HANDLE proc= popen_map[fp];
if (!proc)
{
errno= EINVAL;
return -1;
}
popen_map.erase(fp);
lk.unlock();
fclose(fp);
/* Wait for process to complete, return its exit code.*/
DWORD ret;
if (WaitForSingleObject(proc, INFINITE) || !GetExitCodeProcess(proc, &ret))
{
ret= -1;
errno= EINVAL;
}
CloseHandle(proc);
return ret;
}
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