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
|
/* Buffer primitives for comparison operations.
Copyright (C) 1993, 1995, 1998, 2001-2002, 2006, 2009-2013, 2015-2025 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 <http://www.gnu.org/licenses/>. */
#include <config.h>
#include "cmpbuf.h"
#include <errno.h>
#include <limits.h>
#include <signal.h>
#include <stdckdint.h>
#include <unistd.h>
#include <stdint.h>
#include <inttypes.h>
#include <sys/types.h>
#include "intprops.h"
#include "minmax.h"
/* Read NBYTES bytes from descriptor FD into BUF.
Return the number of characters successfully read.
On error, return -1, setting errno.
The number returned is always NBYTES unless end-of-file or error. */
ptrdiff_t
block_read (int fd, char *buf, idx_t nbytes)
{
char *bp = buf;
char const *buflim = buf + nbytes;
idx_t readlim = MIN (IDX_MAX, MIN (SSIZE_MAX, SIZE_MAX));
do
{
idx_t bytes_remaining = buflim - bp;
idx_t bytes_to_read = MIN (bytes_remaining, readlim);
ssize_t nread = read (fd, bp, bytes_to_read);
if (nread <= 0)
{
if (nread == 0)
break;
/* Accommodate FreeBSD 13, which can't read more than INT_MAX bytes
when debug.iosize_max_clamp is nonzero. Prefer a power
of two for the read limit in this case.
Also, work around a bug in Linux kernel 6.3.8 tmpfs,
which fails if the current offset + bytes_to_read exceeds
TYPE_MAXIMUM (off_t), even if EOF occurs before then. */
if (errno == EINVAL)
{
if (bytes_to_read <= 1)
{
if (lseek (fd, 0, SEEK_CUR) == TYPE_MAXIMUM (off_t))
{
nread = 0;
break;
}
errno = EINVAL;
}
else
{
readlim = MIN (bytes_to_read >> 1, INT_MAX / 2 + 1);
continue;
}
}
/* This is needed for programs that have signal handlers on
older hosts without SA_RESTART. It also accommodates
ancient AIX hosts that set errno to EINTR after uncaught
SIGCONT. See <news:1r77ojINN85n@ftp.UU.NET>
(1993-04-22). */
if (! SA_RESTART && errno == EINTR)
continue;
return -1;
}
bp += nread;
}
while (bp < buflim);
return bp - buf;
}
/* Least common multiple of two buffer sizes A and B. However, if
either A or B is zero, or if the multiple is greater than LCM_MAX,
return a reasonable buffer size. */
idx_t
buffer_lcm (idx_t a, idx_t b, idx_t lcm_max)
{
/* Yield reasonable values if buffer sizes are zero. Although A and
B must be nonnegative, GCC generates better code from (A <= 0)
than from (A != 0). */
if (a <= 0)
return b <= 0 ? 8 * 1024 : b;
if (b <= 0)
return a;
/* n = gcd (a, b) */
idx_t m, n, r;
for (m = a, n = b; (r = m % n) != 0; m = n, n = r)
continue;
/* Yield a if there is an overflow. */
idx_t q = a / n, lcm;
return !ckd_mul (&lcm, b, q) && lcm <= lcm_max ? lcm : a;
}
|
