arch/um/drivers/fd.c

   1 /*
   2  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <unistd.h>
   9 #include <errno.h>
  10 #include <termios.h>
  11 #include "chan_user.h"
  12 #include "kern_constants.h"
  13 #include "os.h"
  14 #include "um_malloc.h"
  15 #include "user.h"
  16
  17 struct fd_chan {
  18         int fd;
  19         int raw;
  20         struct termios tt;
  21         char str[sizeof("1234567890\0")];
  22 };
  23
  24 static void *fd_init(char *str, int device, const struct chan_opts *opts)
  25 {
  26         struct fd_chan *data;
  27         char *end;
  28         int n;
  29
  30         if (*str != ':') {
  31                 printk(UM_KERN_ERR "fd_init : channel type 'fd' must specify a "
  32                        "file descriptor\n");
  33                 return NULL;
  34         }
  35         str++;
  36         n = strtoul(str, &end, 0);
  37         if ((*end != '\0') || (end == str)) {
  38                 printk(UM_KERN_ERR "fd_init : couldn't parse file descriptor "
  39                        "'%s'\n", str);
  40                 return NULL;
  41         }
  42
  43         data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
  44         if (data == NULL)
  45                 return NULL;
  46
  47         *data = ((struct fd_chan) { .fd         = n,
  48                                     .raw        = opts->raw });
  49         return data;
  50 }
  51
  52 static int fd_open(int input, int output, int primary, void *d, char **dev_out)
  53 {
  54         struct fd_chan *data = d;
  55         int err;
  56
  57         if (data->raw && isatty(data->fd)) {
  58                 CATCH_EINTR(err = tcgetattr(data->fd, &data->tt));
  59                 if (err)
  60                         return err;
  61
  62                 err = raw(data->fd);
  63                 if (err)
  64                         return err;
  65         }
  66         sprintf(data->str, "%d", data->fd);
  67         *dev_out = data->str;
  68         return data->fd;
  69 }
  70
  71 static void fd_close(int fd, void *d)
  72 {
  73         struct fd_chan *data = d;
  74         int err;
  75
  76         if (!data->raw || !isatty(fd))
  77                 return;
  78
  79         CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &data->tt));
  80         if (err)
  81                 printk(UM_KERN_ERR "Failed to restore terminal state - "
  82                        "errno = %d\n", -err);
  83         data->raw = 0;
  84 }
  85
  86 const struct chan_ops fd_ops = {
  87         .type           = "fd",
  88         .init           = fd_init,
  89         .open           = fd_open,
  90         .close          = fd_close,
  91         .read           = generic_read,
  92         .write          = generic_write,
  93         .console_write  = generic_console_write,
  94         .window_size    = generic_window_size,
  95         .free           = generic_free,
  96         .winch          = 1,
  97 };