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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - fs/romfs/storage.c
1 /* RomFS storage access routines
3 * Copyright © 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
13 #include <linux/mtd/super.h>
14 #include <linux/buffer_head.h>
17 #if !defined(CONFIG_ROMFS_ON_MTD) && !defined(CONFIG_ROMFS_ON_BLOCK)
18 #error no ROMFS backing store interface configured
21 #ifdef CONFIG_ROMFS_ON_MTD
22 #define ROMFS_MTD_READ(sb, ...) ((sb)->s_mtd->read((sb)->s_mtd, ##__VA_ARGS__))
25 * read data from an romfs image on an MTD device
27 static int romfs_mtd_read(struct super_block
*sb
, unsigned long pos
,
28 void *buf
, size_t buflen
)
33 ret
= ROMFS_MTD_READ(sb
, pos
, buflen
, &rlen
, buf
);
34 return (ret
< 0 || rlen
!= buflen
) ? -EIO
: 0;
38 * determine the length of a string in a romfs image on an MTD device
40 static ssize_t
romfs_mtd_strnlen(struct super_block
*sb
,
41 unsigned long pos
, size_t maxlen
)
49 /* scan the string up to 16 bytes at a time */
51 segment
= min_t(size_t, maxlen
, 16);
52 ret
= ROMFS_MTD_READ(sb
, pos
, segment
, &len
, buf
);
55 p
= memchr(buf
, 0, len
);
67 * compare a string to one in a romfs image on MTD
68 * - return 1 if matched, 0 if differ, -ve if error
70 static int romfs_mtd_strncmp(struct super_block
*sb
, unsigned long pos
,
71 const char *str
, size_t size
)
77 /* scan the string up to 16 bytes at a time */
79 segment
= min_t(size_t, size
, 16);
80 ret
= ROMFS_MTD_READ(sb
, pos
, segment
, &len
, buf
);
83 if (memcmp(buf
, str
, len
) != 0)
92 #endif /* CONFIG_ROMFS_ON_MTD */
94 #ifdef CONFIG_ROMFS_ON_BLOCK
96 * read data from an romfs image on a block device
98 static int romfs_blk_read(struct super_block
*sb
, unsigned long pos
,
99 void *buf
, size_t buflen
)
101 struct buffer_head
*bh
;
102 unsigned long offset
;
105 /* copy the string up to blocksize bytes at a time */
107 offset
= pos
& (ROMBSIZE
- 1);
108 segment
= min_t(size_t, buflen
, ROMBSIZE
- offset
);
109 bh
= sb_bread(sb
, pos
>> ROMBSBITS
);
112 memcpy(buf
, bh
->b_data
+ offset
, segment
);
122 * determine the length of a string in romfs on a block device
124 static ssize_t
romfs_blk_strnlen(struct super_block
*sb
,
125 unsigned long pos
, size_t limit
)
127 struct buffer_head
*bh
;
128 unsigned long offset
;
133 /* scan the string up to blocksize bytes at a time */
135 offset
= pos
& (ROMBSIZE
- 1);
136 segment
= min_t(size_t, limit
, ROMBSIZE
- offset
);
137 bh
= sb_bread(sb
, pos
>> ROMBSBITS
);
140 buf
= bh
->b_data
+ offset
;
141 p
= memchr(buf
, 0, segment
);
144 return n
+ (p
- buf
);
154 * compare a string to one in a romfs image on a block device
155 * - return 1 if matched, 0 if differ, -ve if error
157 static int romfs_blk_strncmp(struct super_block
*sb
, unsigned long pos
,
158 const char *str
, size_t size
)
160 struct buffer_head
*bh
;
161 unsigned long offset
;
165 /* scan the string up to 16 bytes at a time */
167 offset
= pos
& (ROMBSIZE
- 1);
168 segment
= min_t(size_t, size
, ROMBSIZE
- offset
);
169 bh
= sb_bread(sb
, pos
>> ROMBSBITS
);
172 x
= (memcmp(bh
->b_data
+ offset
, str
, segment
) != 0);
183 #endif /* CONFIG_ROMFS_ON_BLOCK */
186 * read data from the romfs image
188 int romfs_dev_read(struct super_block
*sb
, unsigned long pos
,
189 void *buf
, size_t buflen
)
193 limit
= romfs_maxsize(sb
);
196 if (buflen
> limit
- pos
)
197 buflen
= limit
- pos
;
199 #ifdef CONFIG_ROMFS_ON_MTD
201 return romfs_mtd_read(sb
, pos
, buf
, buflen
);
203 #ifdef CONFIG_ROMFS_ON_BLOCK
205 return romfs_blk_read(sb
, pos
, buf
, buflen
);
211 * determine the length of a string in romfs
213 ssize_t
romfs_dev_strnlen(struct super_block
*sb
,
214 unsigned long pos
, size_t maxlen
)
218 limit
= romfs_maxsize(sb
);
221 if (maxlen
> limit
- pos
)
222 maxlen
= limit
- pos
;
224 #ifdef CONFIG_ROMFS_ON_MTD
226 return romfs_mtd_strnlen(sb
, pos
, limit
);
228 #ifdef CONFIG_ROMFS_ON_BLOCK
230 return romfs_blk_strnlen(sb
, pos
, limit
);
236 * compare a string to one in romfs
237 * - return 1 if matched, 0 if differ, -ve if error
239 int romfs_dev_strncmp(struct super_block
*sb
, unsigned long pos
,
240 const char *str
, size_t size
)
244 limit
= romfs_maxsize(sb
);
247 if (size
> ROMFS_MAXFN
)
248 return -ENAMETOOLONG
;
249 if (size
> limit
- pos
)
252 #ifdef CONFIG_ROMFS_ON_MTD
254 return romfs_mtd_strncmp(sb
, pos
, str
, size
);
256 #ifdef CONFIG_ROMFS_ON_BLOCK
258 return romfs_blk_strncmp(sb
, pos
, str
, size
);