xref: /linux/arch/um/drivers/xterm_kern.c (revision d2f6409584e2c62ffad81690562330ff3bf4a458)
1 /*
2  * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
3  * Licensed under the GPL
4  */
5 
6 #include "linux/errno.h"
7 #include "linux/slab.h"
8 #include "linux/signal.h"
9 #include "linux/interrupt.h"
10 #include "asm/irq.h"
11 #include "irq_user.h"
12 #include "irq_kern.h"
13 #include "kern_util.h"
14 #include "os.h"
15 #include "xterm.h"
16 
17 struct xterm_wait {
18 	struct completion ready;
19 	int fd;
20 	int pid;
21 	int new_fd;
22 };
23 
24 static irqreturn_t xterm_interrupt(int irq, void *data, struct pt_regs *regs)
25 {
26 	struct xterm_wait *xterm = data;
27 	int fd;
28 
29 	fd = os_rcv_fd(xterm->fd, &xterm->pid);
30 	if(fd == -EAGAIN)
31 		return(IRQ_NONE);
32 
33 	xterm->new_fd = fd;
34 	complete(&xterm->ready);
35 	return(IRQ_HANDLED);
36 }
37 
38 int xterm_fd(int socket, int *pid_out)
39 {
40 	struct xterm_wait *data;
41 	int err, ret;
42 
43 	data = kmalloc(sizeof(*data), GFP_KERNEL);
44 	if(data == NULL){
45 		printk(KERN_ERR "xterm_fd : failed to allocate xterm_wait\n");
46 		return(-ENOMEM);
47 	}
48 
49 	/* This is a locked semaphore... */
50 	*data = ((struct xterm_wait)
51 		{ .fd 		= socket,
52 		  .pid 		= -1,
53 		  .new_fd 	= -1 });
54 	init_completion(&data->ready);
55 
56 	err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt,
57 			     SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
58 			     "xterm", data);
59 	if (err){
60 		printk(KERN_ERR "xterm_fd : failed to get IRQ for xterm, "
61 		       "err = %d\n",  err);
62 		ret = err;
63 		goto out;
64 	}
65 
66 	/* ... so here we wait for an xterm interrupt.
67 	 *
68 	 * XXX Note, if the xterm doesn't work for some reason (eg. DISPLAY
69 	 * isn't set) this will hang... */
70 	wait_for_completion(&data->ready);
71 
72 	free_irq(XTERM_IRQ, data);
73 
74 	ret = data->new_fd;
75 	*pid_out = data->pid;
76  out:
77 	kfree(data);
78 
79 	return(ret);
80 }
81 
82 /*
83  * Overrides for Emacs so that we follow Linus's tabbing style.
84  * Emacs will notice this stuff at the end of the file and automatically
85  * adjust the settings for this buffer only.  This must remain at the end
86  * of the file.
87  * ---------------------------------------------------------------------------
88  * Local variables:
89  * c-file-style: "linux"
90  * End:
91  */
92