1 /* An interface to read and write that retries after interrupts.
2 Copyright (C) 1993, 1994, 1998, 2002-2003 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software Foundation,
16 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
24 # include "safe-write.h"
26 # include "safe-read.h"
30 #include <sys/types.h>
41 # define IS_EINTR(x) ((x) == EINTR)
43 # define IS_EINTR(x) 0
52 /* The extra casts work around common compiler bugs. */
53 #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
54 /* The outer cast is needed to work around a bug in Cray C 5.0.3.0.
55 It is necessary at least when t == time_t. */
56 #define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \
57 ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))
58 #define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))
61 # define INT_MAX TYPE_MAXIMUM (int)
65 # define safe_rw safe_write
68 # define safe_rw safe_read
71 # define const /* empty */
74 /* Read(write) up to COUNT bytes at BUF from(to) descriptor FD, retrying if
75 interrupted. Return the actual number of bytes read(written), zero for EOF,
76 or SAFE_READ_ERROR(SAFE_WRITE_ERROR) upon error. */
78 safe_rw (int fd, void const *buf, size_t count)
82 /* POSIX limits COUNT to SSIZE_MAX, but we limit it further, requiring
83 that COUNT <= INT_MAX, to avoid triggering a bug in Tru64 5.1.
84 When decreasing COUNT, keep the file pointer block-aligned.
85 Note that in any case, read(write) may succeed, yet read(write)
86 fewer than COUNT bytes, so the caller must be prepared to handle
89 count = INT_MAX & ~8191;
93 result = rw (fd, buf, count);
95 while (result < 0 && IS_EINTR (errno));
97 return (size_t) result;