tty.c

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/*
 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <kern_util.h>
#include <os.h>

struct grantpt_info {
    int fd;
    int res;
    int err;
};

static void grantpt_cb(void *arg)
{
    struct grantpt_info *info = arg;

    info->res = grantpt(info->fd);
    info->err = errno;
}

int get_pty(void)
{
    struct grantpt_info info;
    int fd, err;

    fd = open("/dev/ptmx", O_RDWR);
    if (fd < 0) {
        err = -errno;
        printk(UM_KERN_ERR "get_pty : Couldn't open /dev/ptmx - "
               "err = %d\n", errno);
        return err;
    }

    info.fd = fd;
    initial_thread_cb(grantpt_cb, &info);

    if (info.res < 0) {
        err = -info.err;
        printk(UM_KERN_ERR "get_pty : Couldn't grant pty - "
               "errno = %d\n", -info.err);
        goto out;
    }

    if (unlockpt(fd) < 0) {
        err = -errno;
        printk(UM_KERN_ERR "get_pty : Couldn't unlock pty - "
               "errno = %d\n", errno);
        goto out;
    }
    return fd;
out:
    close(fd);
    return err;
}