Re: gethostname fix for mingw (was: Re: Problem with gethostbyname)

[Bruno Haible]

Ben Pfaff wrote:
>     Fix gethostname on mingw.
>     * lib/unistd.in.h: Bypass bad winsock2 prototype for gethostname.
>     Prevent calling gethostname on mingw without using the gethostname
>     module.
>     * gethostname.m4: Invoke gl_PREREQ_SYS_H_WINSOCK2 if it is
>     available.
>     * doc/posix-functions/gethostname.texi: Update.

Nearly good. I improved two things:

  - "#include <unistd.h>" would make the non-POSIX functions accept(), ...,
    socket(), select() visible.

  - When the module 'gethostname' is requested and the module 'sys_socket'
    is not, then the use of
      #include <unistd.h>
      #include <winsock2.h>
    would lead to a clash of different prototypes of gethostname(). In other
    words, every time you have an m4_ifdef() of a macro defined in another
    gnulib module, there are chances that it's a bug.

and applied this:


2008-10-25  Ben Pfaff  <address@hidden>
            Bruno Haible  <address@hidden>

        * lib/unistd.in.h: Include <winsock2.h>.
        (socket, connect,accept, bind, getpeername, getsockname, getsockopt,
        listen, recv, send, recvfrom, sendto, setsockopt, shutdown, select):
        Provide dummy declarations.
        (gethostname): Override.
        * lib/sys_socket.in.h (gethostname): Provide dummy declaration.
        * m4/gethostname.m4 (gl_FUNC_GETHOSTNAME): Invoke
        gl_PREREQ_SYS_H_WINSOCK2.
        * modules/gethostname (Files): Add m4/sys_socket_h.m4.
        * doc/posix-functions/gethostname.texi: More details.

--- lib/sys_socket.in.h.orig    2008-10-25 23:00:21.000000000 +0200
+++ lib/sys_socket.in.h 2008-10-25 22:57:53.000000000 +0200
@@ -145,6 +145,11 @@
 #  define close close_used_without_including_unistd_h
 # endif
 
+# if @HAVE_WINSOCK2_H@ && !defined _GL_UNISTD_H
+#  undef gethostname
+#  define gethostname gethostname_used_without_including_unistd_h
+# endif
+
 # if @GNULIB_SOCKET@
 #  if @HAVE_WINSOCK2_H@
 #   undef socket
--- lib/unistd.in.h.orig        2008-10-25 23:00:21.000000000 +0200
+++ lib/unistd.in.h     2008-10-25 22:57:53.000000000 +0200
@@ -42,6 +42,47 @@
 # include <sys/types.h>
 #endif
 
+#if @GNULIB_GETHOSTNAME@
+/* Get all possible declarations of gethostname().  */
+# if @UNISTD_H_HAVE_WINSOCK2_H@
+#  include <winsock2.h>
+#  if !defined _GL_SYS_SOCKET_H
+#   undef socket
+#   define socket              socket_used_without_including_sys_socket_h
+#   undef connect
+#   define connect             connect_used_without_including_sys_socket_h
+#   undef accept
+#   define accept              accept_used_without_including_sys_socket_h
+#   undef bind
+#   define bind                        bind_used_without_including_sys_socket_h
+#   undef getpeername
+#   define getpeername         getpeername_used_without_including_sys_socket_h
+#   undef getsockname
+#   define getsockname         getsockname_used_without_including_sys_socket_h
+#   undef getsockopt
+#   define getsockopt          getsockopt_used_without_including_sys_socket_h
+#   undef listen
+#   define listen              listen_used_without_including_sys_socket_h
+#   undef recv
+#   define recv                        recv_used_without_including_sys_socket_h
+#   undef send
+#   define send                        send_used_without_including_sys_socket_h
+#   undef recvfrom
+#   define recvfrom            recvfrom_used_without_including_sys_socket_h
+#   undef sendto
+#   define sendto              sendto_used_without_including_sys_socket_h
+#   undef setsockopt
+#   define setsockopt          setsockopt_used_without_including_sys_socket_h
+#   undef shutdown
+#   define shutdown            shutdown_used_without_including_sys_socket_h
+#  endif
+#  if !defined _GL_SYS_SELECT_H
+#   undef select
+#   define select              select_used_without_including_sys_select_h
+#  endif
+# endif
+#endif
+
 /* The definition of GL_LINK_WARNING is copied here.  */
 
 
@@ -284,9 +325,16 @@
    Null terminate it if the name is shorter than LEN.
    If the host name is longer than LEN, set errno = EINVAL and return -1.
    Return 0 if successful, otherwise set errno and return -1.  */
-# if address@hidden@
+# if @UNISTD_H_HAVE_WINSOCK2_H@
+#  undef gethostname
+#  define gethostname rpl_gethostname
+# endif
+# if @UNISTD_H_HAVE_WINSOCK2_H@ || address@hidden@
 extern int gethostname(char *name, size_t len);
 # endif
+#elif @UNISTD_H_HAVE_WINSOCK2_H@
+# undef gethostname
+# define gethostname 
gethostname_used_without_requesting_gnulib_module_gethostname
 #elif defined GNULIB_POSIXCHECK
 # undef gethostname
 # define gethostname(n,l) \
--- m4/gethostname.m4.orig      2008-10-25 23:00:21.000000000 +0200
+++ m4/gethostname.m4   2008-10-25 22:57:53.000000000 +0200
@@ -1,4 +1,4 @@
-# gethostname.m4 serial 3
+# gethostname.m4 serial 4
 dnl Copyright (C) 2002, 2008 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,6 +7,7 @@
 AC_DEFUN([gl_FUNC_GETHOSTNAME],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+  gl_PREREQ_SYS_H_WINSOCK2
   AC_REPLACE_FUNCS(gethostname)
   if test $ac_cv_func_gethostname = no; then
     HAVE_GETHOSTNAME=0
--- modules/gethostname.orig    2008-10-25 23:00:21.000000000 +0200
+++ modules/gethostname 2008-10-25 22:57:53.000000000 +0200
@@ -4,6 +4,7 @@
 Files:
 lib/gethostname.c
 m4/gethostname.m4
+m4/sys_socket_h.m4
 
 Depends-on:
 unistd
--- doc/posix-functions/gethostname.texi.orig   2008-10-25 23:00:21.000000000 
+0200
+++ doc/posix-functions/gethostname.texi        2008-10-25 22:57:53.000000000 
+0200
@@ -9,8 +9,8 @@
 Portability problems fixed by Gnulib:
 @itemize
 @item
-This function is missing on some platforms:
-mingw.
+On mingw, this function has a prototype that differs from that
+specified by POSIX, and it is defined only in the ws2_32 library.
 @end itemize
 
 Portability problems not fixed by Gnulib: