passfd on FreeBSD

[Bruno Haible]

On FreeBSD 6.4, the compilation succeeds but the test fails:

recvfd: Function not implemented
sendfd: Function not implemented
FAIL: test-passfd

config.log shows this:

configure:7701: checking for UNIX domain sockets SCM_RIGHTS that behave in BSD4.
4 way
configure:7744: gcc -c -g -O2 -Wall conftest.c >&5
conftest.c: In function `main':
conftest.c:98: error: `NULL' undeclared (first use in this function)
conftest.c:98: error: (Each undeclared identifier is reported only once
conftest.c:98: error: for each function it appears in.)
conftest.c:94: warning: unused variable `fdptr'

The reason is that the expansion of CMSG_FIRSTHDR (...) contains a reference to 
NULL.

In <sys/socket.h>:
#define CMSG_NXTHDR(mhdr, cmsg) \
        ((char *)(cmsg) == NULL ? CMSG_FIRSTHDR(mhdr) : \
        ...


2011-03-13  Bruno Haible  <address@hidden>

        passfd: Work around bug with CMSG_FIRSTHDR on FreeBSD 6.4.
        * lib/sys_socket.in.h: Include <stddef.h>.
        * m4/afunix.m4 (gl_SOCKET_AFUNIX): Include <stddef.h> before using
        CMSG_FIRSTHDR. Remove unused variable.

--- lib/sys_socket.in.h.orig    Sun Mar 13 23:51:21 2011
+++ lib/sys_socket.in.h Sun Mar 13 23:50:39 2011
@@ -50,6 +50,10 @@
    <sys/types.h>.  */
 # include <sys/types.h>
 
+/* On FreeBSD 6.4, <sys/socket.h> defines some macros that assume that NULL
+   is defined.  */
+# include <stddef.h>
+
 /* The include_next requires a split double-inclusion guard.  */
 # @INCLUDE_NEXT@ @NEXT_SYS_SOCKET_H@
 
--- m4/afunix.m4.orig   Sun Mar 13 23:51:21 2011
+++ m4/afunix.m4        Sun Mar 13 23:51:11 2011
@@ -1,4 +1,4 @@
-# afunix.m4 serial 3
+# afunix.m4 serial 4
 dnl Copyright (C) 2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -43,6 +43,7 @@
     [AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM(
           [[#include <sys/types.h>
+            #include <stddef.h>
             #ifdef HAVE_SYS_SOCKET_H
             #include <sys/socket.h>
             #endif
@@ -57,7 +58,6 @@
               struct cmsghdr *cmsg;
               int myfds[1] = {0};
               char buf[CMSG_SPACE (sizeof (myfds))];
-              int *fdptr;
 
               msg.msg_control = buf;
               msg.msg_controllen = sizeof buf;

-- 
In memoriam Odette Sansom <http://en.wikipedia.org/wiki/Odette_Hallowes>