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pty.c

/*
 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <termios.h>
#include <sys/stat.h>
#include "chan_user.h"
#include "kern_constants.h"
#include "os.h"
#include "um_malloc.h"
#include "user.h"

struct pty_chan {
      void (*announce)(char *dev_name, int dev);
      int dev;
      int raw;
      struct termios tt;
      char dev_name[sizeof("/dev/pts/0123456\0")];
};

static void *pty_chan_init(char *str, int device, const struct chan_opts *opts)
{
      struct pty_chan *data;

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

      *data = ((struct pty_chan) { .announce    = opts->announce,
                             .dev         = device,
                             .raw         = opts->raw });
      return data;
}

static int pts_open(int input, int output, int primary, void *d,
                char **dev_out)
{
      struct pty_chan *data = d;
      char *dev;
      int fd, err;

      fd = get_pty();
      if (fd < 0) {
            err = -errno;
            printk(UM_KERN_ERR "open_pts : Failed to open pts\n");
            return err;
      }

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

            err = raw(fd);
            if (err)
                  goto out_close;
      }

      dev = ptsname(fd);
      sprintf(data->dev_name, "%s", dev);
      *dev_out = data->dev_name;

      if (data->announce)
            (*data->announce)(dev, data->dev);

      return fd;

out_close:
      close(fd);
      return err;
}

static int getmaster(char *line)
{
      struct stat buf;
      char *pty, *bank, *cp;
      int master, err;

      pty = &line[strlen("/dev/ptyp")];
      for (bank = "pqrs"; *bank; bank++) {
            line[strlen("/dev/pty")] = *bank;
            *pty = '0';
            /* Did we hit the end ? */
            if ((stat(line, &buf) < 0) && (errno == ENOENT))
                  break;

            for (cp = "0123456789abcdef"; *cp; cp++) {
                  *pty = *cp;
                  master = open(line, O_RDWR);
                  if (master >= 0) {
                        char *tp = &line[strlen("/dev/")];

                        /* verify slave side is usable */
                        *tp = 't';
                        err = access(line, R_OK | W_OK);
                        *tp = 'p';
                        if (!err)
                              return master;
                        close(master);
                  }
            }
      }

      printk(UM_KERN_ERR "getmaster - no usable host pty devices\n");
      return -ENOENT;
}

static int pty_open(int input, int output, int primary, void *d,
                char **dev_out)
{
      struct pty_chan *data = d;
      int fd, err;
      char dev[sizeof("/dev/ptyxx\0")] = "/dev/ptyxx";

      fd = getmaster(dev);
      if (fd < 0)
            return fd;

      if (data->raw) {
            err = raw(fd);
            if (err) {
                  close(fd);
                  return err;
            }
      }

      if (data->announce)
            (*data->announce)(dev, data->dev);

      sprintf(data->dev_name, "%s", dev);
      *dev_out = data->dev_name;

      return fd;
}

const struct chan_ops pty_ops = {
      .type       = "pty",
      .init       = pty_chan_init,
      .open       = pty_open,
      .close            = generic_close,
      .read       = generic_read,
      .write            = generic_write,
      .console_write    = generic_console_write,
      .window_size      = generic_window_size,
      .free       = generic_free,
      .winch            = 0,
};

const struct chan_ops pts_ops = {
      .type       = "pts",
      .init       = pty_chan_init,
      .open       = pts_open,
      .close            = generic_close,
      .read       = generic_read,
      .write            = generic_write,
      .console_write    = generic_console_write,
      .window_size      = generic_window_size,
      .free       = generic_free,
      .winch            = 0,
};

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