arch/um/drivers/tty.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
   4  */
   5
   6 #include <errno.h>
   7 #include <fcntl.h>
   8 #include <termios.h>
   9 #include "chan_user.h"
  10 #include <os.h>
  11 #include <um_malloc.h>
  12
  13 struct tty_chan {
  14         char *dev;
  15         int raw;
  16         struct termios tt;
  17 };
  18
  19 static void *tty_chan_init(char *str, int device, const struct chan_opts *opts)
  20 {
  21         struct tty_chan *data;
  22
  23         if (*str != ':') {
  24                 printk(UM_KERN_ERR "tty_init : channel type 'tty' must specify "
  25                        "a device\n");
  26                 return NULL;
  27         }
  28         str++;
  29
  30         data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
  31         if (data == NULL)
  32                 return NULL;
  33         *data = ((struct tty_chan) { .dev       = str,
  34                                      .raw       = opts->raw });
  35
  36         return data;
  37 }
  38
  39 static int tty_open(int input, int output, int primary, void *d,
  40                     char **dev_out)
  41 {
  42         struct tty_chan *data = d;
  43         int fd, err, mode = 0;
  44
  45         if (input && output)
  46                 mode = O_RDWR;
  47         else if (input)
  48                 mode = O_RDONLY;
  49         else if (output)
  50                 mode = O_WRONLY;
  51
  52         fd = open(data->dev, mode);
  53         if (fd < 0)
  54                 return -errno;
  55
  56         if (data->raw) {
  57                 CATCH_EINTR(err = tcgetattr(fd, &data->tt));
  58                 if (err)
  59                         return err;
  60
  61                 err = raw(fd);
  62                 if (err)
  63                         return err;
  64         }
  65
  66         *dev_out = data->dev;
  67         return fd;
  68 }
  69
  70 const struct chan_ops tty_ops = {
  71         .type           = "tty",
  72         .init           = tty_chan_init,
  73         .open           = tty_open,
  74         .close          = generic_close,
  75         .read           = generic_read,
  76         .write          = generic_write,
  77         .console_write  = generic_console_write,
  78         .window_size    = generic_window_size,
  79         .free           = generic_free,
  80         .winch          = 0,
  81 };