-/* 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 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
#endif
/* 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>
# define INT_MAX TYPE_MAXIMUM (int)
#endif
-/* We don't pass an nbytes count > SSIZE_MAX to read() - POSIX says the
- effect would be implementation-defined. Also we don't pass an nbytes
- count > INT_MAX but <= SSIZE_MAX to read() - this triggers a bug in
- Tru64 5.1. */
-#define MAX_BYTES_TO_READ INT_MAX
+#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_READ_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)
{
- size_t nbytes_to_read = count;
ssize_t result;
- /* Limit the number of bytes to read, to avoid running into unspecified
- behaviour. But keep the file pointer block aligned when doing so.
- Note that in this case we don't need to call read() multiple times here,
- because the caller is prepared to partial results. */
- if (nbytes_to_read > MAX_BYTES_TO_READ)
- nbytes_to_read = MAX_BYTES_TO_READ & ~8191;
+ /* 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(write) may succeed, yet read(write)
+ fewer than COUNT bytes, so the caller must be prepared to handle
+ partial results. */
+ if (count > INT_MAX)
+ count = INT_MAX & ~8191;
do
{
- result = read (fd, buf, nbytes_to_read);
+ result = rw (fd, buf, count);
}
while (result < 0 && IS_EINTR (errno));