1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <linux/slab.h>
7#include <linux/completion.h>
8#include <linux/irqreturn.h>
9#include <asm/irq.h>
10#include <irq_kern.h>
11#include <os.h>
12#include "xterm.h"
13
14struct xterm_wait {
15	struct completion ready;
16	int fd;
17	int pid;
18	int new_fd;
19};
20
21static irqreturn_t xterm_interrupt(int irq, void *data)
22{
23	struct xterm_wait *xterm = data;
24	int fd;
25
26	fd = os_rcv_fd(xterm->fd, &xterm->pid);
27	if (fd == -EAGAIN)
28		return IRQ_NONE;
29
30	xterm->new_fd = fd;
31	complete(&xterm->ready);
32
33	return IRQ_HANDLED;
34}
35
36int xterm_fd(int socket, int *pid_out)
37{
38	struct xterm_wait *data;
39	int err, ret;
40
41	data = kmalloc(sizeof(*data), GFP_KERNEL);
42	if (data == NULL) {
43		printk(KERN_ERR "xterm_fd : failed to allocate xterm_wait\n");
44		return -ENOMEM;
45	}
46
47	/* This is a locked semaphore... */
48	*data = ((struct xterm_wait) { .fd 		= socket,
49				       .pid 		= -1,
50				       .new_fd	 	= -1 });
51	init_completion(&data->ready);
52
53	err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt,
54			     IRQF_SHARED, "xterm", data);
55	if (err < 0) {
56		printk(KERN_ERR "xterm_fd : failed to get IRQ for xterm, "
57		       "err = %d\n",  err);
58		ret = err;
59		goto out;
60	}
61
62	/* ... so here we wait for an xterm interrupt.
63	 *
64	 * XXX Note, if the xterm doesn't work for some reason (eg. DISPLAY
65	 * isn't set) this will hang... */
66	wait_for_completion(&data->ready);
67
68	um_free_irq(XTERM_IRQ, data);
69
70	ret = data->new_fd;
71	*pid_out = data->pid;
72 out:
73	kfree(data);
74
75	return ret;
76}
77