xref: /linux/arch/um/drivers/fd.c (revision 6ee738610f41b59733f63718f0bdbcba7d3a3f12)
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 "kern_constants.h"
13 #include "os.h"
14 #include "um_malloc.h"
15 #include "user.h"
16 
17 struct fd_chan {
18 	int fd;
19 	int raw;
20 	struct termios tt;
21 	char str[sizeof("1234567890\0")];
22 };
23 
24 static void *fd_init(char *str, int device, const struct chan_opts *opts)
25 {
26 	struct fd_chan *data;
27 	char *end;
28 	int n;
29 
30 	if (*str != ':') {
31 		printk(UM_KERN_ERR "fd_init : channel type 'fd' must specify a "
32 		       "file descriptor\n");
33 		return NULL;
34 	}
35 	str++;
36 	n = strtoul(str, &end, 0);
37 	if ((*end != '\0') || (end == str)) {
38 		printk(UM_KERN_ERR "fd_init : couldn't parse file descriptor "
39 		       "'%s'\n", str);
40 		return NULL;
41 	}
42 
43 	data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
44 	if (data == NULL)
45 		return NULL;
46 
47 	*data = ((struct fd_chan) { .fd  	= n,
48 				    .raw  	= opts->raw });
49 	return data;
50 }
51 
52 static int fd_open(int input, int output, int primary, void *d, char **dev_out)
53 {
54 	struct fd_chan *data = d;
55 	int err;
56 
57 	if (data->raw && isatty(data->fd)) {
58 		CATCH_EINTR(err = tcgetattr(data->fd, &data->tt));
59 		if (err)
60 			return err;
61 
62 		err = raw(data->fd);
63 		if (err)
64 			return err;
65 	}
66 	sprintf(data->str, "%d", data->fd);
67 	*dev_out = data->str;
68 	return data->fd;
69 }
70 
71 static void fd_close(int fd, void *d)
72 {
73 	struct fd_chan *data = d;
74 	int err;
75 
76 	if (!data->raw || !isatty(fd))
77 		return;
78 
79 	CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &data->tt));
80 	if (err)
81 		printk(UM_KERN_ERR "Failed to restore terminal state - "
82 		       "errno = %d\n", -err);
83 	data->raw = 0;
84 }
85 
86 const struct chan_ops fd_ops = {
87 	.type		= "fd",
88 	.init		= fd_init,
89 	.open		= fd_open,
90 	.close		= fd_close,
91 	.read		= generic_read,
92 	.write		= generic_write,
93 	.console_write	= generic_console_write,
94 	.window_size	= generic_window_size,
95 	.free		= generic_free,
96 	.winch		= 1,
97 };
98