inet_ntop fix for mingw32

[Simon Josefsson]

A GnuTLS user reported that inet_ntop did not build on mingw32, so I
took a look at it.  The patch below fixes:

* Add "restrict" keywords, as per POSIX.

* Don't include sys/socket.h or netinet/in.h, as they didn't appear to
  be necessary?  The sys/socket.h file was the one causing problems
  here (mingw32 doesn't have it).  If sys/socket.h and/or netinet/in.h
  really is needed on some system, we should add a check for it in
  inet_ntop.m4 and only conditionally include it in inet_ntop.h.

* Protect the function declaration around HAVE_DECL_INET_NTOP rather
  than HAVE_INET_NTOP.

* Don't use K&R prototypes.

* Check the sprintf return values.

* Re-define EAFNOSUPPORT if not present, this did also not exist on
  mingw32.  Perhaps this should be moved to a separate module, though,
  as it make the code look ugly because of non-POSIX platforms, which
  is bad style.

* Ran "indent" on the files.

I have not tested this on many platforms yet, so the sys/socket.h and
netinet/in.h issue may turn out to be flawed here.  But I intend to
check this soon, fixing this is one of two things blocking GnuTLS
1.2.9, and I will test it on many platforms before the release.

Ok to install?

Thanks!

Index: m4/inet_ntop.m4
===================================================================
RCS file: /cvsroot/gnulib/gnulib/m4/inet_ntop.m4,v
retrieving revision 1.1
diff -u -p -u -w -r1.1 inet_ntop.m4
--- m4/inet_ntop.m4     9 May 2005 15:15:14 -0000       1.1
+++ m4/inet_ntop.m4     24 Oct 2005 23:26:38 -0000
@@ -12,5 +12,7 @@ AC_DEFUN([gl_INET_NTOP],
 
 # Prerequisites of lib/inet_ntop.h and lib/inet_ntop.c.
 AC_DEFUN([gl_PREREQ_INET_NTOP], [
+  AC_CHECK_HEADERS_ONCE(sys/types.h arpa/inet.h)
+  AC_CHECK_DECLS([inet_ntop],,,[#include <arpa/inet.h>])
   AC_REQUIRE([gl_SOCKET_FAMILIES])
 ])
Index: modules/inet_ntop
===================================================================
RCS file: /cvsroot/gnulib/gnulib/modules/inet_ntop,v
retrieving revision 1.2
diff -u -p -u -w -r1.2 inet_ntop
--- modules/inet_ntop   25 Sep 2005 08:17:38 -0000      1.2
+++ modules/inet_ntop   24 Oct 2005 23:26:38 -0000
@@ -8,6 +8,7 @@ m4/inet_ntop.m4
 m4/sockpfaf.m4
 
 Depends-on:
+restrict
 socklen
 
 configure.ac:
Index: lib/inet_ntop.h
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/inet_ntop.h,v
retrieving revision 1.3
diff -u -p -u -w -r1.3 inet_ntop.h
--- lib/inet_ntop.h     11 Jul 2005 11:21:55 -0000      1.3
+++ lib/inet_ntop.h     24 Oct 2005 23:26:38 -0000
@@ -16,9 +16,9 @@
    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 
 #include <sys/types.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
+#ifdef HAVE_ARPA_INET_H
 #include <arpa/inet.h>
+#endif
 
 /* Converts an internet address from internal format to a printable,
    presentable format.
@@ -36,6 +36,7 @@
    For more details, see the POSIX:2001 specification
    <http://www.opengroup.org/susv3xsh/inet_ntop.html>.  */
 
-#if !HAVE_INET_NTOP /* not already defined and declared in <arpa/inet.h> ? */
-extern const char *inet_ntop(int af, const void *src, char *dst, socklen_t 
cnt);
+#ifndef HAVE_DECL_INET_NTOP
+extern const char *inet_ntop (int af, const void *restrict src,
+                             char *restrict dst, socklen_t cnt);
 #endif
Index: lib/inet_ntop.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/inet_ntop.c,v
retrieving revision 1.2
diff -u -p -u -w -r1.2 inet_ntop.c
--- lib/inet_ntop.c     19 Sep 2005 17:28:14 -0000      1.2
+++ lib/inet_ntop.c     24 Oct 2005 23:26:38 -0000
@@ -1,6 +1,22 @@
+/* inet_ntop.c -- convert IPv4 and IPv6 addresses from binary to text form
+   Copyright (c) 2005  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
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
 /*
  * Copyright (c) 1996-1999 by Internet Software Consortium.
- * Copyright (c) 2005  Free Software Foundation, Inc.
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -27,6 +43,10 @@
 #include <string.h>
 #include <errno.h>
 
+#ifndef EAFNOSUPPORT
+# define EAFNOSUPPORT EINVAL
+#endif
+
 #define NS_IN6ADDRSZ 16
 #define NS_INT16SZ 2
 
@@ -53,14 +73,11 @@ static const char *inet_ntop6 (const uns
  *     Paul Vixie, 1996.
  */
 const char *
-inet_ntop(af, src, dst, size)
-       int af;
-       const void *src;
-       char *dst;
-       socklen_t size;
+inet_ntop (int af, const void *restrict src,
+          char *restrict dst, socklen_t cnt)
+{
+  switch (af)
 {
-       switch (af) {
-
 #if HAVE_IPV4
        case AF_INET:
                return (inet_ntop4(src, dst, size));
@@ -70,6 +87,7 @@ inet_ntop(af, src, dst, size)
        case AF_INET6:
                return (inet_ntop6(src, dst, size));
 #endif
+
        default:
                errno = EAFNOSUPPORT;
                return (NULL);
@@ -91,18 +109,21 @@ inet_ntop(af, src, dst, size)
  *     Paul Vixie, 1996.
  */
 static const char *
-inet_ntop4(src, dst, size)
-       const unsigned char *src;
-       char *dst;
-       socklen_t size;
+inet_ntop4 (const unsigned char *src, char *dst, socklen_t size)
 {
-       static const char fmt[] = "%u.%u.%u.%u";
        char tmp[sizeof "255.255.255.255"];
+  int len;
 
-       if (sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) > size) {
+  len = sprintf (tmp, "%u.%u.%u.%u", src[0], src[1], src[2], src[3]);
+  if (len < 0)
+    return NULL;
+
+  if (len > size)
+    {
                errno = ENOSPC;
-               return (NULL);
+      return NULL;
        }
+
        return strcpy(dst, tmp);
 }
 
@@ -117,10 +138,7 @@ inet_ntop4(src, dst, size)
  *     Paul Vixie, 1996.
  */
 static const char *
-inet_ntop6(src, dst, size)
-       const unsigned char *src;
-       char *dst;
-       socklen_t size;
+inet_ntop6 (const unsigned char *src, char *dst, socklen_t size)
 {
        /*
         * Note that int32_t and int16_t need only be "at least" large enough
@@ -130,7 +148,10 @@ inet_ntop6(src, dst, size)
         * to use pointer overlays.  All the world's not a VAX.
         */
        char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
-       struct { int base, len; } best, cur;
+  struct
+  {
+    int base, len;
+  } best, cur;
        unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
        int i;
 
@@ -144,21 +165,27 @@ inet_ntop6(src, dst, size)
                words[i / 2] = (src[i] << 8) | src[i + 1];
        best.base = -1;
        cur.base = -1;
-       for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
-               if (words[i] == 0) {
+  for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++)
+    {
+      if (words[i] == 0)
+       {
                        if (cur.base == -1)
                                cur.base = i, cur.len = 1;
                        else
                                cur.len++;
-               } else {
-                       if (cur.base != -1) {
+       }
+      else
+       {
+         if (cur.base != -1)
+           {
                                if (best.base == -1 || cur.len > best.len)
                                        best = cur;
                                cur.base = -1;
                        }
                }
        }
-       if (cur.base != -1) {
+  if (cur.base != -1)
+    {
                if (best.base == -1 || cur.len > best.len)
                        best = cur;
        }
@@ -169,10 +196,11 @@ inet_ntop6(src, dst, size)
         * Format the result.
         */
        tp = tmp;
-       for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
+  for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++)
+    {
                /* Are we inside the best run of 0x00's? */
-               if (best.base != -1 && i >= best.base &&
-                   i < (best.base + best.len)) {
+      if (best.base != -1 && i >= best.base && i < (best.base + best.len))
+       {
                        if (i == best.base)
                                *tp++ = ':';
                        continue;
@@ -182,13 +210,19 @@ inet_ntop6(src, dst, size)
                        *tp++ = ':';
                /* Is this address an encapsulated IPv4? */
                if (i == 6 && best.base == 0 &&
-                   (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
+         (best.len == 6 || (best.len == 5 && words[5] == 0xffff)))
+       {
                        if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
                                return (NULL);
                        tp += strlen(tp);
                        break;
                }
-               tp += sprintf(tp, "%x", words[i]);
+      {
+       int len = sprintf (tp, "%x", words[i]);
+       if (len < 0)
+         return NULL;
+       tp += len;
+      }
        }
        /* Was it a trailing run of 0x00's? */
        if (best.base != -1 && (best.base + best.len) ==
@@ -199,10 +233,12 @@ inet_ntop6(src, dst, size)
        /*
         * Check for overflow, copy, and we're done.
         */
-       if ((socklen_t)(tp - tmp) > size) {
+  if ((socklen_t) (tp - tmp) > size)
+    {
                errno = ENOSPC;
-               return (NULL);
+      return NULL;
        }
+
        return strcpy(dst, tmp);
 }