xref: /freebsd/stand/common/md.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * Copyright (c) 2009 Marcel Moolenaar
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 #include <stand.h>
29 #include <sys/param.h>
30 #include <sys/endian.h>
31 #include <sys/queue.h>
32 #include <machine/stdarg.h>
33 
34 #include "bootstrap.h"
35 
36 #define	MD_BLOCK_SIZE	512
37 
38 #ifndef MD_IMAGE_SIZE
39 #error Must be compiled with MD_IMAGE_SIZE defined
40 #endif
41 #if (MD_IMAGE_SIZE == 0 || MD_IMAGE_SIZE % MD_BLOCK_SIZE)
42 #error Image size must be a multiple of 512.
43 #endif
44 
45 /*
46  * Preloaded image gets put here.
47  * Applications that patch the object with the image can determine
48  * the size looking at the start and end markers (strings),
49  * so we want them contiguous.
50  */
51 static struct {
52 	u_char start[MD_IMAGE_SIZE];
53 	u_char end[128];
54 } md_image = {
55 	.start = "MFS Filesystem goes here",
56 	.end = "MFS Filesystem had better STOP here",
57 };
58 
59 /* devsw I/F */
60 static int md_init(void);
61 static int md_strategy(void *, int, daddr_t, size_t, char *, size_t *);
62 static int md_open(struct open_file *, ...);
63 static int md_close(struct open_file *);
64 static int md_print(int);
65 
66 struct devsw md_dev = {
67 	.dv_name = "md",
68 	.dv_type = DEVT_DISK,
69 	.dv_init = md_init,
70 	.dv_strategy = md_strategy,
71 	.dv_open = md_open,
72 	.dv_close = md_close,
73 	.dv_ioctl = noioctl,
74 	.dv_print = md_print,
75 	.dv_cleanup = nullsys,
76 };
77 
78 static int
79 md_init(void)
80 {
81 
82 	return (0);
83 }
84 
85 static int
86 md_strategy(void *devdata, int rw, daddr_t blk, size_t size,
87     char *buf, size_t *rsize)
88 {
89 	struct devdesc *dev = (struct devdesc *)devdata;
90 	size_t ofs;
91 
92 	if (dev->d_unit != 0)
93 		return (ENXIO);
94 
95 	if (blk < 0 || blk >= (MD_IMAGE_SIZE / MD_BLOCK_SIZE))
96 		return (EIO);
97 
98 	if (size % MD_BLOCK_SIZE)
99 		return (EIO);
100 
101 	ofs = blk * MD_BLOCK_SIZE;
102 	if ((ofs + size) > MD_IMAGE_SIZE)
103 		size = MD_IMAGE_SIZE - ofs;
104 
105 	if (rsize != NULL)
106 		*rsize = size;
107 
108 	switch (rw & F_MASK) {
109 	case F_READ:
110 		bcopy(md_image.start + ofs, buf, size);
111 		return (0);
112 	case F_WRITE:
113 		bcopy(buf, md_image.start + ofs, size);
114 		return (0);
115 	}
116 
117 	return (ENODEV);
118 }
119 
120 static int
121 md_open(struct open_file *f, ...)
122 {
123 	va_list ap;
124 	struct devdesc *dev;
125 
126 	va_start(ap, f);
127 	dev = va_arg(ap, struct devdesc *);
128 	va_end(ap);
129 
130 	if (dev->d_unit != 0)
131 		return (ENXIO);
132 
133 	return (0);
134 }
135 
136 static int
137 md_close(struct open_file *f)
138 {
139 	struct devdesc *dev;
140 
141 	dev = (struct devdesc *)(f->f_devdata);
142 	return ((dev->d_unit != 0) ? ENXIO : 0);
143 }
144 
145 static int
146 md_print(int verbose)
147 {
148 
149 	printf("%s devices:", md_dev.dv_name);
150 	if (pager_output("\n") != 0)
151 		return (1);
152 
153 	printf("MD (%u bytes)", MD_IMAGE_SIZE);
154 	return (pager_output("\n"));
155 }
156