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