net_if: new module

OpenBSD's <net/if.h> is not self-contained; this should compile:

| #define _POSIX_C_SOURCE 200809L
| #include <net/if.h>
| struct if_nameindex i;

but fails with:

In file included from foo.c:2:
/usr/include/net/if.h:112: error: expected specifier-qualifier-list before 'u_int'
...
/usr/include/net/if.h:674: error: field 'dstaddr' has incomplete type
In file included from /usr/include/net/if.h:691,
                 from foo.c:2:
/usr/include/net/if_arp.h:79: error: field 'arp_pa' has incomplete type
/usr/include/net/if_arp.h:80: error: field 'arp_ha' has incomplete type
*** Error code 1

We already had a test program for systems with the if_* functions
(including OpenBSD); but in adding this module, I had to enhance
that test to also work on platforms like mingw where we are now
providing a new header.

* modules/net_if: New module, borrowing ideas from netinet_in.
* m4/net_if_h.m4: New file.
* lib/net_if.in.h: Likewise.
* doc/posix-headers/net_if.texi (net/if.h): Document it.
* MODULES.html.sh (lacking POSIX:2008): Likewise.
* tests/test-net_if.c: Make function checks conditional.
Reported by Jasper Lievisse Adriaanse <jasper@humppa.nl>.

Signed-off-by: Eric Blake <eblake@redhat.com>

diff --git a/ChangeLog b/ChangeLog
index dea1f86..d9f6f89 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2012-09-05  Eric Blake  <eblake@redhat.com>
+
+       net_if: new module
+       * modules/net_if: New module, borrowing ideas from netinet_in.
+       * m4/net_if_h.m4: New file.
+       * lib/net_if.in.h: Likewise.
+       * doc/posix-headers/net_if.texi (net/if.h): Document it.
+       * MODULES.html.sh (lacking POSIX:2008): Likewise.
+       * tests/test-net_if.c: Make function checks conditional.
+       Reported by Jasper Lievisse Adriaanse <jasper@humppa.nl>.
+
 2012-09-05  Mats Erik Andersson  <gnu@gisladisker.se>  (tiny change)
 
        readutmp: fix non-portable UT_PID use

diff --git a/MODULES.html.sh b/MODULES.html.sh
index 8ced611..0e34531 100755 (executable)
--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -2430,6 +2430,7 @@ func_all_modules ()
   func_module mkfifo
   func_module mknod
   func_module mkstemp
+  func_module net_if
   func_module netdb
   func_module netinet_in
   func_module nl_langinfo

diff --git a/doc/posix-headers/net_if.texi b/doc/posix-headers/net_if.texi
index 38a52f4..fa01b6e 100644 (file)
--- a/doc/posix-headers/net_if.texi
+++ b/doc/posix-headers/net_if.texi
@@ -3,10 +3,13 @@
 
 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/basedefs/net_if.h.html}
 
-Gnulib module: ---
+Gnulib module: net_if
 
 Portability problems fixed by Gnulib:
 @itemize
+@item
+This header file is not self-contained on some platforms:
+FreeBSD 8.2, OpenBSD 5.1.
 @end itemize
 
 Portability problems not fixed by Gnulib:

diff --git a/lib/net_if.in.h b/lib/net_if.in.h
new file mode 100644 (file)
index 0000000..24f9f83
--- /dev/null
+++ b/lib/net_if.in.h
@@ -0,0 +1,53 @@
+/* Substitute for <net/if.h>.
+   Copyright (C) 2007-2012 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, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef _@GUARD_PREFIX@_NET_IF_H
+
+#if __GNUC__ >= 3
+@PRAGMA_SYSTEM_HEADER@
+#endif
+@PRAGMA_COLUMNS@
+
+#if @HAVE_NET_IF_H@
+
+/* On some platforms, <net/if.h> assumes prior inclusion of
+   <sys/socket.h>.  */
+# include <sys/socket.h>
+
+/* The include_next requires a split double-inclusion guard.  */
+# @INCLUDE_NEXT@ @NEXT_NET_IF_H@
+
+#endif
+
+#ifndef _@GUARD_PREFIX@_NET_IF_H
+#define _@GUARD_PREFIX@_NET_IF_H
+
+#if !@HAVE_NET_IF_H@
+
+/* A platform that lacks <net/if.h>.  */
+
+struct if_nameindex
+{
+  unsigned if_index;
+  char *if_name;
+};
+
+# define IF_NAMESIZE 1 /* Without if_* functions, this supports only "". */
+
+#endif
+
+#endif /* _@GUARD_PREFIX@_NET_IF_H */
+#endif /* _@GUARD_PREFIX@_NET_IF_H */

diff --git a/m4/net_if_h.m4 b/m4/net_if_h.m4
new file mode 100644 (file)
index 0000000..171101f
--- /dev/null
+++ b/m4/net_if_h.m4
@@ -0,0 +1,31 @@
+# net_if_h.m4 serial 1
+dnl Copyright (C) 2006-2012 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_HEADER_NET_IF],
+[
+  AC_CACHE_CHECK([whether <net/if.h> is self-contained],
+    [gl_cv_header_net_if_h_selfcontained],
+    [
+      AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <net/if.h>]], [[]])],
+        [gl_cv_header_net_if_h_selfcontained=yes],
+        [gl_cv_header_net_if_h_selfcontained=no])
+    ])
+  if test $gl_cv_header_net_if_h_selfcontained = yes; then
+    NET_IF_H=''
+  else
+    NET_IF_H='net/if.h'
+    AC_CHECK_HEADERS([net/if.h], [], [], [[#include <sys/socket.h>]])
+    gl_NEXT_HEADERS([net/if.h])
+    if test $ac_cv_header_net_if_h = yes; then
+      HAVE_NET_IF_H=1
+    else
+      HAVE_NET_IF_H=0
+    fi
+    AC_SUBST([HAVE_NET_IF_H])
+  fi
+  AC_SUBST([NET_IF_H])
+  AM_CONDITIONAL([GL_GENERATE_NET_IF_H], [test -n "$NET_IF_H"])
+])

diff --git a/modules/net_if b/modules/net_if
new file mode 100644 (file)
index 0000000..9e30f01
--- /dev/null
+++ b/modules/net_if
@@ -0,0 +1,49 @@
+Description:
+A <net/if.h> for systems lacking it.
+
+Files:
+lib/net_if.in.h
+m4/net_if_h.m4
+
+Depends-on:
+include_next
+sys_socket
+
+configure.ac:
+gl_HEADER_NET_IF
+AC_PROG_MKDIR_P
+
+Makefile.am:
+BUILT_SOURCES += $(NET_IF_H)
+
+# We need the following in order to create <net/if.h> when the system
+# doesn't have one.
+if GL_GENERATE_NET_IF_H
+net/if.h: net_if.in.h $(top_builddir)/config.status
+       $(AM_V_at)$(MKDIR_P) net
+       $(AM_V_GEN)rm -f $@-t $@ && \
+       { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
+         sed -e 's|@''GUARD_PREFIX''@|${gl_include_guard_prefix}|g' \
+             -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
+             -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
+             -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
+             -e 's|@''NEXT_NET_IF_H''@|$(NEXT_NET_IF_H)|g' \
+             -e 's|@''HAVE_NET_IF_H''@|$(HAVE_NET_IF_H)|g' \
+             < $(srcdir)/net_if.in.h; \
+       } > $@-t && \
+       mv $@-t $@
+else
+net/if.h: $(top_builddir)/config.status
+       rm -f $@
+endif
+MOSTLYCLEANFILES += net/if.h net/if.h-t
+MOSTLYCLEANDIRS += net
+
+Include:
+<net/if.h>
+
+License:
+LGPLv2+
+
+Maintainer:
+Eric Blake

diff --git a/tests/test-net_if.c b/tests/test-net_if.c
index ee3cdbd..f508642 100644 (file)
--- a/tests/test-net_if.c
+++ b/tests/test-net_if.c
@@ -20,11 +20,17 @@
 
 #include <net/if.h>
 
-#include "signature.h"
+static struct if_nameindex ni;
+
+/* We do not yet have replacements for if_* functions on systems that
+   lack a native <net/if.h>.  */
+#if HAVE_NET_IF_H
+# include "signature.h"
 SIGNATURE_CHECK (if_freenameindex, void, (struct if_nameindex *));
 SIGNATURE_CHECK (if_indextoname, char *, (unsigned int, char *));
 SIGNATURE_CHECK (if_nameindex, struct if_nameindex *, (void));
 SIGNATURE_CHECK (if_nametoindex, unsigned int, (const char *));
+#endif
 
 #include <stddef.h> /* NULL */
 #include <stdio.h> /* fprintf */
@@ -32,6 +38,7 @@ SIGNATURE_CHECK (if_nametoindex, unsigned int, (const char *));
 int
 main (int argc, char *argv[])
 {
+#if HAVE_NET_IF_H
   struct if_nameindex *ifnp, *p;
 
   p = ifnp = if_nameindex ();
@@ -80,6 +87,7 @@ main (int argc, char *argv[])
     }
 
   if_freenameindex (ifnp);
+#endif /* HAVE_NET_IF_H */
 
-  return 0;
+  return !IF_NAMESIZE + ni.if_index + !!ni.if_name;
 }