xref: /openbmc/linux/arch/um/drivers/fd.c (revision 275876e2)
1 /*
2  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
3  * Licensed under the GPL
4  */
5 
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <unistd.h>
9 #include <errno.h>
10 #include <termios.h>
11 #include "chan_user.h"
12 #include <os.h>
13 #include <um_malloc.h>
14 
15 struct fd_chan {
16 	int fd;
17 	int raw;
18 	struct termios tt;
19 	char str[sizeof("1234567890\0")];
20 };
21 
22 static void *fd_init(char *str, int device, const struct chan_opts *opts)
23 {
24 	struct fd_chan *data;
25 	char *end;
26 	int n;
27 
28 	if (*str != ':') {
29 		printk(UM_KERN_ERR "fd_init : channel type 'fd' must specify a "
30 		       "file descriptor\n");
31 		return NULL;
32 	}
33 	str++;
34 	n = strtoul(str, &end, 0);
35 	if ((*end != '\0') || (end == str)) {
36 		printk(UM_KERN_ERR "fd_init : couldn't parse file descriptor "
37 		       "'%s'\n", str);
38 		return NULL;
39 	}
40 
41 	data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
42 	if (data == NULL)
43 		return NULL;
44 
45 	*data = ((struct fd_chan) { .fd  	= n,
46 				    .raw  	= opts->raw });
47 	return data;
48 }
49 
50 static int fd_open(int input, int output, int primary, void *d, char **dev_out)
51 {
52 	struct fd_chan *data = d;
53 	int err;
54 
55 	if (data->raw && isatty(data->fd)) {
56 		CATCH_EINTR(err = tcgetattr(data->fd, &data->tt));
57 		if (err)
58 			return err;
59 
60 		err = raw(data->fd);
61 		if (err)
62 			return err;
63 	}
64 	sprintf(data->str, "%d", data->fd);
65 	*dev_out = data->str;
66 	return data->fd;
67 }
68 
69 static void fd_close(int fd, void *d)
70 {
71 	struct fd_chan *data = d;
72 	int err;
73 
74 	if (!data->raw || !isatty(fd))
75 		return;
76 
77 	CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &data->tt));
78 	if (err)
79 		printk(UM_KERN_ERR "Failed to restore terminal state - "
80 		       "errno = %d\n", -err);
81 	data->raw = 0;
82 }
83 
84 const struct chan_ops fd_ops = {
85 	.type		= "fd",
86 	.init		= fd_init,
87 	.open		= fd_open,
88 	.close		= fd_close,
89 	.read		= generic_read,
90 	.write		= generic_write,
91 	.console_write	= generic_console_write,
92 	.window_size	= generic_window_size,
93 	.free		= generic_free,
94 	.winch		= 1,
95 };
96