popen_replacement1.c - Win32 |_popen()| replacement
Posted by Anonymous on Tue 28th Nov 2023 07:57
raw | new post


/*
 *
 * popen_replacement1.c - Win32 |_popen()| replacement
 * since Win32 _popen() keeps triggering EINVAL
 *
 * Written by Roland Mainz <roland.mainz@nrubsig.org>
 */
#define UNICODE 1
#define _UNICODE 1

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>


typedef struct {
    HANDLE hReadPipe;
    HANDLE hWritePipe;
    PROCESS_INFORMATION pi;
} PIPE_INFO;

PIPE_INFO *mypopen(const char *command, const char *mode) {
    static PIPE_INFO gpinfo = {0};
    PIPE_INFO *pinfo = &gpinfo;
    STARTUPINFOA si;
    SECURITY_ATTRIBUTES sa = { 0 };
    sa.nLength = sizeof(SECURITY_ATTRIBUTES);
    sa.bInheritHandle = TRUE;
    sa.lpSecurityDescriptor = NULL;

    if (!command || !mode) {
        return NULL;
    }

    // Create a pipe for communication between the parent and child processes.
    if (!CreatePipe(&pinfo->hReadPipe, &pinfo->hWritePipe, &sa, 0)) {
        (void)puts("pipe error");
        return NULL;
    }

    // Set the pipe handles to non-inheritable.
    if (!SetHandleInformation(pinfo->hReadPipe, HANDLE_FLAG_INHERIT, FALSE)) {
        CloseHandle(pinfo->hReadPipe);
        CloseHandle(pinfo->hWritePipe);
        (void)puts("SetHandleInformation error");
        return NULL;
    }

    // Initialize the STARTUPINFO structure.
    ZeroMemory(&si, sizeof(si));
    si.cb = sizeof(si);
    si.hStdInput = NULL;
    si.hStdOutput = pinfo->hWritePipe;
    si.hStdError = GetStdHandle(STD_ERROR_HANDLE) /* pinfo->hWritePipe*/;
    si.dwFlags |= STARTF_USESTDHANDLES;

    // Create the child process.
    if (!CreateProcessA(NULL, (LPSTR)command, NULL, NULL, TRUE, 0/*DETACHED_PROCESS*/, NULL, NULL, &si, &pinfo->pi)) {
        CloseHandle(pinfo->hReadPipe);
        CloseHandle(pinfo->hWritePipe);
        (void)puts("cannot create process");
        return NULL;
    }

    // Close the write handle to the pipe from the parent process.
    CloseHandle(pinfo->hWritePipe);

    return pinfo;
}

int mypclose(PIPE_INFO *pinfo) {
    DWORD status;

    // Close the read handle to the pipe from the child process.
    CloseHandle(pinfo->hReadPipe);

    // Wait for the child process to terminate.
    WaitForSingleObject(pinfo->pi.hProcess, INFINITE);

    // Get the exit code of the child process.
    if (!GetExitCodeProcess(pinfo->pi.hProcess, &status)) {
        status = -1;
    }

    // Close the process handles.
    CloseHandle(pinfo->pi.hProcess);
    CloseHandle(pinfo->pi.hThread);

    (void)printf("exit code=%d\n", (int)status);

    return status;
}

int main(int ac, char *av[])
{
        (void)puts("# start.");
        PIPE_INFO *pinfo = mypopen("C:\\cygwin64\\bin\\dir.exe", "r");
        if (pinfo) {
                char buf[1024];
                DWORD n;

                while (ReadFile(pinfo->hReadPipe, buf, sizeof(buf), &n, NULL)) {
                        buf[n] = '\0';
                        printf("|%s|,n=%ld\n", buf, (long)n);
                }

                mypclose(pinfo);
        }
        (void)puts("# done.");
        return 0;
}