-/* An interface to read that retries after interrupts.
- Copyright (C) 1993, 1994, 1998, 2002 Free Software Foundation, Inc.
+/* An interface to read and write that retries after interrupts.
+
+ Copyright (C) 1993, 1994, 1998, 2002, 2003, 2004, 2005, 2006 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
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. */
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
-#if HAVE_CONFIG_H
-# include <config.h>
-#endif
+#include <config.h>
/* Specification. */
-#include "safe-read.h"
+#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 <unistd.h>
#include <errno.h>
-#ifndef errno
-extern int errno;
-#endif
#ifdef EINTR
# define IS_EINTR(x) ((x) == EINTR)
#include <limits.h>
-#ifndef CHAR_BIT
-# define CHAR_BIT 8
-#endif
-
-/* The extra casts work around common compiler bugs. */
-#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
-/* The outer cast is needed to work around a bug in Cray C 5.0.3.0.
- It is necessary at least when t == time_t. */
-#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \
- ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))
-#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))
-
-#ifndef INT_MAX
-# define INT_MAX TYPE_MAXIMUM (int)
+#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 up to COUNT bytes at BUF from descriptor FD, retrying if interrupted.
- Return the actual number of bytes read, zero for EOF, or SAFE_RW_ERROR
- upon error. */
+/* 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_read (int fd, void *buf, size_t count)
+safe_rw (int fd, void const *buf, size_t count)
{
- ssize_t result;
-
- /* POSIX limits COUNT to SSIZE_MAX, but we limit it further, requiring
- that COUNT <= INT_MAX, to avoid triggering a bug in Tru64 5.1.
- When decreasing COUNT, keep the file pointer block-aligned.
- Note that in any case, read may succeed, yet read fewer than COUNT
- bytes, so the caller must be prepared to handle partial results. */
- if (count > INT_MAX)
- count = INT_MAX & ~8191;
+ /* 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 };
- do
+ for (;;)
{
- result = read (fd, buf, count);
+ 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;
}
- while (result < 0 && IS_EINTR (errno));
-
- return (size_t) result;
}