1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
/* word_io.c -- word oriented I/O
Copyright (C) 2007-2023 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/* config.h must be included first. */
#include <config.h>
/* system headers. */
#include <errno.h>
#include <stdbool.h> /* for bool */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* gnulib headers. */
#include "byteswap.h"
#include "error.h"
#include "quotearg.h"
/* find headers. */
#include "system.h"
#include "die.h"
#include "locatedb.h"
enum { WORDBYTES=4 };
static int
decode_value (const unsigned char data[],
int limit,
GetwordEndianState *endian_state_flag,
const char *filename)
{
int swapped;
union
{
int ival; /* native representation */
unsigned char data[WORDBYTES];
} u;
u.ival = 0;
memcpy (&u.data, data, WORDBYTES);
swapped = bswap_32(u.ival); /* byteswapped */
if (*endian_state_flag == GetwordEndianStateInitial)
{
if (u.ival <= limit)
{
if (swapped > limit)
{
/* the native value is inside the limit and the
* swapped value is not. We take this as proof
* that we should be using the native byte order.
*/
*endian_state_flag = GetwordEndianStateNative;
}
return u.ival;
}
else
{
if (swapped <= limit)
{
/* Aha, now we know we have to byte-swap. */
error (0, 0,
_("WARNING: locate database %s was "
"built with a different byte order"),
quotearg_n_style (0, locale_quoting_style, filename));
*endian_state_flag = GetwordEndianStateSwab;
return swapped;
}
else
{
/* u.ival > limit and swapped > limit. For the moment, assume
* native ordering.
*/
return u.ival;
}
}
}
else
{
/* We already know the byte order. */
if (*endian_state_flag == GetwordEndianStateSwab)
return swapped;
else
return u.ival;
}
}
int
getword (FILE *fp,
const char *filename,
size_t maxvalue,
GetwordEndianState *endian_state_flag)
{
unsigned char data[4];
size_t bytes_read;
clearerr (fp);
bytes_read = fread (data, WORDBYTES, 1, fp);
if (bytes_read != 1)
{
const char * quoted_name = quotearg_n_style (0, locale_quoting_style,
filename);
/* Distinguish between a truncated database and an I/O error.
* Either condition is fatal.
*/
if (feof (fp))
die (EXIT_FAILURE, 0, _("unexpected EOF in %s"), quoted_name);
else
die (EXIT_FAILURE, errno,
_("error reading a word from %s"), quoted_name);
abort ();
}
else
{
return decode_value (data, maxvalue, endian_state_flag, filename);
}
}
|
