// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <termios.h>
#include "chan_user.h"
#include <os.h>
#include <um_malloc.h>

struct fd_chan {
        int fd;
        int raw;
        struct termios tt;
        char str[sizeof("1234567890\0")];
};

static void *fd_init(char *str, int device, const struct chan_opts *opts)
{
        struct fd_chan *data;
        char *end;
        int n;

        if (*str != ':') {
                printk(UM_KERN_ERR "fd_init : channel type 'fd' must specify a "
                       "file descriptor\n");
                return NULL;
        }
        str++;
        n = strtoul(str, &end, 0);
        if ((*end != '\0') || (end == str)) {
                printk(UM_KERN_ERR "fd_init : couldn't parse file descriptor "
                       "'%s'\n", str);
                return NULL;
        }

        data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
        if (data == NULL)
                return NULL;

        *data = ((struct fd_chan) { .fd         = n,
                                    .raw        = opts->raw });
        return data;
}

static int fd_open(int input, int output, int primary, void *d, char **dev_out)
{
        struct fd_chan *data = d;
        int err;

        if (data->raw && isatty(data->fd)) {
                CATCH_EINTR(err = tcgetattr(data->fd, &data->tt));
                if (err)
                        return err;

                err = raw(data->fd);
                if (err)
                        return err;
        }
        sprintf(data->str, "%d", data->fd);
        *dev_out = data->str;
        return data->fd;
}

static void fd_close(int fd, void *d)
{
        struct fd_chan *data = d;
        int err;

        if (!data->raw || !isatty(fd))
                return;

        CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &data->tt));
        if (err)
                printk(UM_KERN_ERR "Failed to restore terminal state - "
                       "errno = %d\n", -err);
        data->raw = 0;
}

const struct chan_ops fd_ops = {
        .type           = "fd",
        .init           = fd_init,
        .open           = fd_open,
        .close          = fd_close,
        .read           = generic_read,
        .write          = generic_write,
        .console_write  = generic_console_write,
        .window_size    = generic_window_size,
        .free           = generic_free,
        .winch          = 1,
};