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
|
/* An interface to read and write that retries after interrupts.
Copyright (C) 1993, 1994, 1998, 2002, 2003, 2004 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 2, 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, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
/* Specification. */
#ifdef SAFE_WRITE
# include "safe-write.h"
#else
# include "safe-read.h"
#endif
/* Get ssize_t. */
#include <sys/types.h>
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <errno.h>
#ifdef EINTR
# define IS_EINTR(x) ((x) == EINTR)
#else
# define IS_EINTR(x) 0
#endif
#include <limits.h>
#ifdef SAFE_WRITE
# define safe_rw safe_write
# define rw write
#else
# define safe_rw safe_read
# define rw read
# undef const
# define const /* empty */
#endif
/* Read(write) up to COUNT bytes at BUF from(to) descriptor FD, retrying if
interrupted. Return the actual number of bytes read(written), zero for EOF,
or SAFE_READ_ERROR(SAFE_WRITE_ERROR) upon error. */
size_t
safe_rw (int fd, void const *buf, size_t count)
{
/* Work around a bug in Tru64 5.1. Attempting to read more than
INT_MAX bytes fails with errno == EINVAL. See
<http://lists.gnu.org/archive/html/bug-gnu-utils/2002-04/msg00010.html>.
When decreasing COUNT, keep it block-aligned. */
enum { BUGGY_READ_MAXIMUM = INT_MAX & ~8191 };
for (;;)
{
ssize_t result = rw (fd, buf, count);
if (0 <= result)
return result;
else if (IS_EINTR (errno))
continue;
else if (errno == EINVAL && BUGGY_READ_MAXIMUM < count)
count = BUGGY_READ_MAXIMUM;
else
return result;
}
}
|
