+
+#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;