SDL/src/process/SDL_process.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"

#include "SDL_sysprocess.h"


SDL_Process *SDL_CreateProcess(const char * const *args, SDL_bool pipe_stdio)
{
    if (!args || !args[0] || !args[0][0]) {
        SDL_InvalidParamError("args");
        return NULL;
    }

    SDL_Process *process;
    SDL_PropertiesID props = SDL_CreateProperties();
    SDL_SetPointerProperty(props, SDL_PROP_PROCESS_CREATE_ARGS_POINTER, (void *)args);
    if (pipe_stdio) {
        SDL_SetNumberProperty(props, SDL_PROP_PROCESS_CREATE_STDIN_NUMBER, SDL_PROCESS_STDIO_APP);
        SDL_SetNumberProperty(props, SDL_PROP_PROCESS_CREATE_STDOUT_NUMBER, SDL_PROCESS_STDIO_APP);
    }
    process = SDL_CreateProcessWithProperties(props);
    SDL_DestroyProperties(props);
    return process;
}

SDL_Process *SDL_CreateProcessWithProperties(SDL_PropertiesID props)
{
    const char * const *args = SDL_GetPointerProperty(props, SDL_PROP_PROCESS_CREATE_ARGS_POINTER, NULL);
    if (!args || !args[0] || !args[0][0]) {
        SDL_InvalidParamError("SDL_PROP_PROCESS_CREATE_ARGS_POINTER");
        return NULL;
    }

    SDL_Process *process = (SDL_Process *)SDL_calloc(1, sizeof(*process));
    if (!process) {
        return NULL;
    }

    process->props = SDL_CreateProperties();
    if (!process->props) {
        SDL_DestroyProcess(process);
        return NULL;
    }

    if (!SDL_SYS_CreateProcessWithProperties(process, props)) {
        SDL_DestroyProcess(process);
        return NULL;
    }
    process->alive = true;
    return process;
}

SDL_PropertiesID SDL_GetProcessProperties(SDL_Process *process)
{
    if (!process) {
        return SDL_InvalidParamError("process");
    }
    return process->props;
}

void *SDL_ReadProcess(SDL_Process *process, size_t *datasize, int *exitcode)
{
    void *result;

    if (datasize) {
        *datasize = 0;
    }
    if (exitcode) {
        *exitcode = -1;
    }

    if (!process) {
        SDL_InvalidParamError("process");
        return NULL;
    }

    SDL_IOStream *io = (SDL_IOStream *)SDL_GetPointerProperty(process->props, SDL_PROP_PROCESS_STDOUT_POINTER, NULL);
    if (!io) {
        SDL_SetError("Process not created with I/O enabled");
        return NULL;
    }

    result = SDL_LoadFile_IO(io, datasize, false);

    SDL_WaitProcess(process, true, exitcode);

    return result;
}

SDL_bool SDL_WriteProcess(SDL_Process *process, const void *ptr, size_t size, SDL_bool closeio)
{
    bool result = false;
    SDL_IOStream *io = NULL;

    if (!process) {
        SDL_InvalidParamError("process");
        goto done;
    }

    io = (SDL_IOStream *)SDL_GetPointerProperty(process->props, SDL_PROP_PROCESS_STDIN_POINTER, NULL);
    if (!io) {
        SDL_SetError("Process not created with I/O enabled");
        goto done;
    }

    size_t written = 0, left = size;
    while (left > 0) {
        size_t amount = SDL_WriteIO(io, (Uint8 *)ptr + written, left);
        if (amount > 0) {
            written += amount;
            left -= amount;
            continue;
        } else if (SDL_GetIOStatus(io) == SDL_IO_STATUS_NOT_READY) {
            // Wait for the stream to be ready
            SDL_Delay(1);
            continue;
        }

        // The stream status will remain set for the caller to check
        break;
    }

    result = (written == size);

done:
    if (result) {
        result = SDL_FlushIO(io);
    }
    if (closeio) {
        result &= SDL_CloseIO(io);
    }
    return result;
}

SDL_bool SDL_KillProcess(SDL_Process *process, SDL_bool force)
{
    if (!process) {
        return SDL_InvalidParamError("process");
    }

    if (!process->alive) {
        return SDL_SetError("Process isn't running");
    }

    return SDL_SYS_KillProcess(process, force);
}

SDL_bool SDL_WaitProcess(SDL_Process *process, SDL_bool block, int *exitcode)
{
    if (!process) {
        return SDL_InvalidParamError("process");
    }

    if (!process->alive) {
        if (exitcode) {
            *exitcode = process->exitcode;
        }
        return true;
    }

    if (SDL_SYS_WaitProcess(process, block, &process->exitcode)) {
        process->alive = false;
        if (exitcode) {
            *exitcode = process->exitcode;
        }
        return true;
    }
    return false;
}

void SDL_DestroyProcess(SDL_Process *process)
{
    if (!process) {
        return;
    }

    // Check to see if the process has exited, will reap zombies on POSIX platforms
    if (process->alive) {
        SDL_WaitProcess(process, false, NULL);
    }

    SDL_SYS_DestroyProcess(process);
    SDL_DestroyProperties(process->props);
    SDL_free(process);
}