2 * A tool for reading the zlib compressed calibration data
3 * found in AVM Fritz!Box based devices).
5 * Copyright (c) 2017 Christian Lamparter <chunkeey@googlemail.com>
7 * Based on zpipe, which is an example of proper use of zlib's inflate().
8 * that is Not copyrighted -- provided to the public domain
9 * Version 1.4 11 December 2005 Mark Adler
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License along
22 * with this program; if not, write to the Free Software Foundation, Inc.,
23 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
38 static inline size_t special_min(size_t a
, size_t b
)
40 return a
== 0 ? b
: (a
< b
? a
: b
);
43 /* Decompress from file source to file dest until stream ends or EOF.
44 inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
45 allocated for processing, Z_DATA_ERROR if the deflate data is
46 invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
47 the version of the library linked do not match, or Z_ERRNO if there
48 is an error reading or writing the files. */
49 static int inf(FILE *source
, FILE *dest
, size_t limit
, size_t skip
)
54 unsigned char in
[CHUNK
];
55 unsigned char out
[CHUNK
];
57 /* allocate inflate state */
62 strm
.next_in
= Z_NULL
;
63 ret
= inflateInit(&strm
);
67 /* decompress until deflate stream ends or end of file */
69 strm
.avail_in
= fread(in
, 1, CHUNK
, source
);
71 (void)inflateEnd(&strm
);
74 if (strm
.avail_in
== 0)
78 /* run inflate() on input until output buffer not full */
80 strm
.avail_out
= CHUNK
;
82 ret
= inflate(&strm
, Z_NO_FLUSH
);
83 assert(ret
!= Z_STREAM_ERROR
); /* state not clobbered */
86 ret
= Z_DATA_ERROR
; /* and fall through */
89 (void)inflateEnd(&strm
);
92 have
= special_min(limit
, CHUNK
- strm
.avail_out
) - skip
;
93 if (fwrite(&out
[skip
], have
, 1, dest
) != 1 || ferror(dest
)) {
94 (void)inflateEnd(&strm
);
99 } while (strm
.avail_out
== 0 && limit
> 0);
101 /* done when inflate() says it's done */
102 } while (ret
!= Z_STREAM_END
&& limit
> 0);
104 /* clean up and return */
105 (void)inflateEnd(&strm
);
106 return (limit
== 0 ? Z_OK
: (ret
== Z_STREAM_END
? Z_OK
: Z_DATA_ERROR
));
109 /* report a zlib or i/o error */
110 static void zerr(int ret
)
115 fputs("error reading stdin\n", stderr
);
117 fputs("error writing stdout\n", stderr
);
120 fputs("invalid compression level\n", stderr
);
123 fputs("invalid or incomplete deflate data\n", stderr
);
126 fputs("out of memory\n", stderr
);
128 case Z_VERSION_ERROR
:
129 fputs("zlib version mismatch!\n", stderr
);
133 static unsigned int get_num(char *str
)
135 if (!strncmp("0x", str
, 2))
136 return strtoul(str
+2, NULL
, 16);
138 return strtoul(str
, NULL
, 10);
141 static void usage(void)
143 fprintf(stderr
, "Usage: fritz_cal_extract [-s seek offset] [-i skip] [-o output file] [-l limit] [infile] -e entry_id\n"
144 "Finds and extracts zlib compressed calibration data in the EVA loader\n");
151 } __attribute__((packed
));
153 /* compress or decompress from stdin to stdout */
154 int main(int argc
, char **argv
)
156 struct cal_entry cal
= { .len
= 0 };
159 size_t limit
= 0, skip
= 0;
160 int initial_offset
= 0;
165 while ((opt
= getopt(argc
, argv
, "s:e:o:l:i:")) != -1) {
168 initial_offset
= (int)get_num(optarg
);
170 perror("Failed to parse seek offset");
175 entry
= (int) htobe16(get_num(optarg
));
177 perror("Failed to entry id");
182 out
= fopen(optarg
, "w");
184 perror("Failed to create output file");
189 limit
= (size_t)get_num(optarg
);
191 perror("Failed to parse limit");
196 skip
= (size_t)get_num(optarg
);
198 perror("Failed to parse skip");
210 if (argc
> 1 && optind
<= argc
) {
211 in
= fopen(argv
[optind
], "r");
213 perror("Failed to create output file");
218 if (initial_offset
) {
219 ret
= fseek(in
, initial_offset
, SEEK_CUR
);
221 perror("Failed to seek to calibration table");
227 ret
= fseek(in
, be16toh(cal
.len
), SEEK_CUR
);
229 fprintf(stderr
, "Reached end of file, but didn't find the matching entry\n");
231 } else if (ferror(in
)) {
232 perror("Failure during seek");
236 ret
= fread(&cal
, 1, sizeof cal
, in
);
237 if (ret
!= sizeof cal
)
239 } while (entry
!= cal
.id
|| cal
.id
== 0xffff);
241 if (cal
.id
== 0xffff) {
242 fprintf(stderr
, "Reached end of filesystem, but didn't find the matching entry\n");
246 ret
= inf(in
, out
, limit
, skip
);