[src/trunk]: src/lib/libc/stdlib Compatibility fixes in reallocarr(3)

[kamil <kamil%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/1e2f630b8824
branches:  trunk
changeset: 339559:1e2f630b8824
user:      kamil <kamil%NetBSD.org@localhost>
date:      Tue Jul 28 17:13:34 2015 +0000

description:
Compatibility fixes in reallocarr(3)

Make this work on !NetBSD platforms:
- replace __CTASSERT() with platform agnostic solution SQRT_SIZE_MAX
- include nbtool_config.h for cross builds to get definition of __RCSID()
- restore errno in the last rare code path for platforms affecting errno(2)
  in memcpy(2)

While there: rename parameter name 'num' to 'number' to be in sync with
the calloc(3) parameter naming.

Reported by scole_mail at the current-users ml.

diffstat:

 lib/libc/stdlib/reallocarr.3 |   4 ++--
 lib/libc/stdlib/reallocarr.c |  27 +++++++++++++++++++--------
 2 files changed, 21 insertions(+), 10 deletions(-)

diffs (92 lines):

diff -r 6c916706fec5 -r 1e2f630b8824 lib/libc/stdlib/reallocarr.3
--- a/lib/libc/stdlib/reallocarr.3      Tue Jul 28 16:51:25 2015 +0000
+++ b/lib/libc/stdlib/reallocarr.3      Tue Jul 28 17:13:34 2015 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: reallocarr.3,v 1.3 2015/02/19 23:08:21 wiz Exp $
+.\"    $NetBSD: reallocarr.3,v 1.4 2015/07/28 17:13:34 kamil Exp $
 .\"
 .\" Copyright (c) 2015 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -37,7 +37,7 @@
 .Ft int
 .Fo reallocarr
 .Fa "void *ptr"
-.Fa "size_t num"
+.Fa "size_t number"
 .Fa "size_t size"
 .Fc
 .Sh DESCRIPTION
diff -r 6c916706fec5 -r 1e2f630b8824 lib/libc/stdlib/reallocarr.c
--- a/lib/libc/stdlib/reallocarr.c      Tue Jul 28 16:51:25 2015 +0000
+++ b/lib/libc/stdlib/reallocarr.c      Tue Jul 28 17:13:34 2015 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: reallocarr.c,v 1.2 2015/07/16 00:03:59 kamil Exp $ */
+/* $NetBSD: reallocarr.c,v 1.3 2015/07/28 17:13:34 kamil Exp $ */
 
 /*-
  * Copyright (c) 2015 Joerg Sonnenberger <joerg%NetBSD.org@localhost>.
@@ -29,8 +29,12 @@
  * SUCH DAMAGE.
  */
 
+#if HAVE_NBTOOL_CONFIG_H
+#include "nbtool_config.h"
+#endif
+
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: reallocarr.c,v 1.2 2015/07/16 00:03:59 kamil Exp $");
+__RCSID("$NetBSD: reallocarr.c,v 1.3 2015/07/28 17:13:34 kamil Exp $");
 
 #include "namespace.h"
 #include <errno.h>
@@ -40,16 +44,17 @@
 #include <stdlib.h>
 #include <string.h>
 
-__CTASSERT(65535 < SIZE_MAX / 65535);
-
 #ifdef _LIBC
 #ifdef __weak_alias
 __weak_alias(reallocarr, _reallocarr)
 #endif
 #endif
 
+#define SQRT_SIZE_MAX (1UL << (sizeof(size_t) << 2))
+
+#if !HAVE_REALLOCARR
 int
-reallocarr(void *ptr, size_t num, size_t size)
+reallocarr(void *ptr, size_t number, size_t size)
 {
        int saved_errno, result;
        void *optr;
@@ -57,16 +62,21 @@
 
        saved_errno = errno;
        memcpy(&optr, ptr, sizeof(ptr));
-       if (num == 0 || size == 0) {
+       if (number == 0 || size == 0) {
                free(optr);
                nptr = NULL;
                memcpy(ptr, &nptr, sizeof(ptr));
                errno = saved_errno;
                return 0;
        }
-       if ((num >= 65535 || size >= 65535) && num > SIZE_MAX / size)
+
+       if ((number >= SQRT_SIZE_MAX || size >= SQRT_SIZE_MAX) &&
+           number > SIZE_MAX / size) {
+               errno = saved_errno;
                return EOVERFLOW;
-       nptr = realloc(optr, num * size);
+       }
+
+       nptr = realloc(optr, number * size);
        if (nptr == NULL) {
                result = errno;
        } else {
@@ -76,3 +86,4 @@
        errno = saved_errno;
        return result;
 }
+#endif