X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fsafe-read.c;h=c21d1cf194004aa02ca07673d8d89d1f9add95c7;hb=666c0198a7da7d033e11ced241814f17fc82ae29;hp=527653c5cc7e6bd0fbdf0e2cd6761162b672dd04;hpb=9b59e36232adca7f1e07894e8ecf77244e9fa331;p=gnulib.git

diff --git a/lib/safe-read.c b/lib/safe-read.c
index 527653c5c..c21d1cf19 100644
--- a/lib/safe-read.c
+++ b/lib/safe-read.c
@@ -1,5 +1,5 @@
-/* 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
@@ -20,7 +20,11 @@
 #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>
@@ -33,56 +37,46 @@
 extern int errno;
 #endif
 
-#include <limits.h>
-
-#ifndef CHAR_BIT
-# define CHAR_BIT 8
+#ifdef EINTR
+# define IS_EINTR(x) ((x) == EINTR)
+#else
+# define IS_EINTR(x) 0
 #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)
-#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
+#include <limits.h>
 
-#ifndef EINTR
-/* If a system doesn't have support for EINTR, define it
-   to be a value to which errno will never be set.  */
-# define EINTR (INT_MAX - 10)
+#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.  */
-  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 && errno == EINTR);
+  while (result < 0 && IS_EINTR (errno));
 
   return (size_t) result;
 }