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(size: 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(x: &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(objp: data);
74
75 return ret;
76}
77

source code of linux/arch/um/drivers/xterm_kern.c