text: /* 
   * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   * Licensed under the GPL
   */
  
  #include <linux/slab.h>
  #include <linux/completion.h>
  #include <linux/irqreturn.h>
  #include <asm/irq.h>
  #include "irq_kern.h"
  #include "os.h"
  
  struct xterm_wait {
  	struct completion ready;
  	int fd;
  	int pid;
  	int new_fd;
  };
  
  static irqreturn_t xterm_interrupt(int irq, void *data)
  {
  	struct xterm_wait *xterm = data;
  	int fd;
  
  	fd = os_rcv_fd(xterm->fd, &xterm->pid);
  	if (fd == -EAGAIN)
  		return IRQ_NONE;
  
  	xterm->new_fd = fd;
  	complete(&xterm->ready);
  
  	return IRQ_HANDLED;
  }
  
  int xterm_fd(int socket, int *pid_out)
  {
  	struct xterm_wait *data;
  	int err, ret;
  
  	data = kmalloc(sizeof(*data), GFP_KERNEL);
  	if (data == NULL) {
  		printk(KERN_ERR "xterm_fd : failed to allocate xterm_wait\n");
  		return -ENOMEM;
  	}
  
  	/* This is a locked semaphore... */
  	*data = ((struct xterm_wait) { .fd 		= socket,
  				       .pid 		= -1,
  				       .new_fd	 	= -1 });
  	init_completion(&data->ready);
  
  	err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt,
  			     IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
  			     "xterm", data);
  	if (err) {
  		printk(KERN_ERR "xterm_fd : failed to get IRQ for xterm, "
  		       "err = %d\n",  err);
  		ret = err;
  		goto out;
  	}
  
  	wait_for_completion(&data->ready);
  
  	free_irq(XTERM_IRQ, data);
  
  	ret = data->new_fd;
  	*pid_out = data->pid;
   out:
  	kfree(data);
  
  	return ret;
  }
  