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
|
/* An interface to write() that retries after interrupts.
Copyright (C) 1993, 1994, 1998, 2002 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. */
#include "safe-write.h"
/* Get ssize_t. */
#include <sys/types.h>
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <errno.h>
#ifndef errno
extern int errno;
#endif
#include <limits.h>
/* We don't pass an nbytes count > SSIZE_MAX to write() - POSIX says the
effect would be implementation-defined. Also we don't pass an nbytes
count > INT_MAX but <= SSIZE_MAX to write() - this triggers a bug in
Tru64 5.1. */
#define MAX_BYTES_TO_READ INT_MAX
/* Write up to COUNT bytes at BUF to descriptor FD, retrying if interrupted.
Return the actual number of bytes written, zero for EOF, or (size_t) -1
for an error. */
size_t
safe_write (int fd, const void *buf, size_t count)
{
size_t total_written = 0;
if (count > 0)
{
const char *ptr = (const char *) buf;
do
{
size_t nbytes_to_write = count;
ssize_t result;
/* Limit the number of bytes to write in one round, to avoid running
into unspecified behaviour. But keep the file pointer block
aligned when doing so. */
if (nbytes_to_write > MAX_BYTES_TO_READ)
nbytes_to_write = MAX_BYTES_TO_READ & ~8191;
result = write (fd, ptr, nbytes_to_write);
if (result < 0)
{
#ifdef EINTR
if (errno == EINTR)
continue;
#endif
return result;
}
total_written += result;
ptr += result;
count -= result;
}
while (count > 0);
}
return total_written;
}
|
