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
14 struct xterm_wait {
15 struct completion ready;
16 int fd;
17 int pid;
18 int new_fd;
19 };
20
21 static irqreturn_t xterm_interrupt(int irq, void *data)
22 {
23 struct xterm_wait *xterm = data;
24 int fd = -1, n_fds = 1;
25 ssize_t ret;
26
27 ret = os_rcv_fd_msg(xterm->fd, &fd, n_fds,
28 &xterm->pid, sizeof(xterm->pid));
29 if (ret == -EAGAIN)
30 return IRQ_NONE;
31
32 if (ret < 0)
33 fd = ret;
34 else if (ret != sizeof(xterm->pid))
35 fd = -EMSGSIZE;
36
37 xterm->new_fd = fd;
38 complete(&xterm->ready);
39
40 return IRQ_HANDLED;
41 }
42
43 int xterm_fd(int socket, int *pid_out)
44 {
45 struct xterm_wait *data;
46 int err, ret;
47
48 data = kmalloc(sizeof(*data), GFP_KERNEL);
49 if (data == NULL) {
50 printk(KERN_ERR "xterm_fd : failed to allocate xterm_wait\n");
51 return -ENOMEM;
52 }
53
54 /* This is a locked semaphore... */
55 *data = ((struct xterm_wait) { .fd = socket,
56 .pid = -1,
57 .new_fd = -1 });
58 init_completion(&data->ready);
59
60 err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt,
61 IRQF_SHARED, "xterm", data);
62 if (err < 0) {
63 printk(KERN_ERR "xterm_fd : failed to get IRQ for xterm, "
64 "err = %d\n", err);
65 ret = err;
66 goto out;
67 }
68
69 /* ... so here we wait for an xterm interrupt.
70 *
71 * XXX Note, if the xterm doesn't work for some reason (eg. DISPLAY
72 * isn't set) this will hang... */
73 wait_for_completion(&data->ready);
74
75 um_free_irq(XTERM_IRQ, data);
76
77 ret = data->new_fd;
78 *pid_out = data->pid;
79 out:
80 kfree(data);
81
82 return ret;
83 }
84
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