Added <ifaddrs.h> interface with functions `getifaddrs', `freeifaddrs'.

	This implementation supports only IPv4.
	* inet/ifaddrs.h: New file.
	* sysdeps/generic/ifaddrs.c: New file.
	* sysdeps/gnu/ifaddrs.c: New file.
	* inet/test-ifaddrs.c: New file.
	* inet/Makefile (routines): Add ifaddrs.
	(headers): Add ifaddrs.h here.
	(tests): Add test-ifaddrs.
	* inet/Versions (GLIBC_2.3): New set, add getifaddrs and freeifaddrs.

	* resolv/res_hconf.c (_res_hconf_reorder_addrs): Use an explicit
	socket call to get an AF_INET socket, instead of using __opensock.
	The SIOCGIFNETMASK ioctl will work only with a PF_INET socket.

	* sysdeps/generic/ifreq.h (__ifreq): Take third argument SOCKFD,
	if not -1 use it instead of calling __opensock.
	* sysdeps/unix/sysv/linux/ifreq.h (__ifreq): Likewise.
	* sysdeps/mach/hurd/ifreq.h (__ifreq): Take new argument and ignore it.
	* resolv/res_hconf.c (_res_hconf_reorder_addrs): Pass new argument.

	* sysdeps/mach/hurd/ifreq.h: New file.
	* sysdeps/generic/ifreq.h (__if_freereq): Take second argument NUM_IFS.
	* sysdeps/unix/sysv/linux/ifreq.h (__if_freereq): Likewise.
	* resolv/res_hconf.c (_res_hconf_reorder_addrs): Update caller.

11 files changed, 485 insertions, 22 deletions

diff --git a/ChangeLog b/ChangeLog
index f18226a604..eb30b68569 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,31 @@
 2002-07-24  Roland McGrath  <roland@frob.com>
 
+	Added <ifaddrs.h> interface with functions `getifaddrs', `freeifaddrs'.
+	This implementation supports only IPv4.
+	* inet/ifaddrs.h: New file.
+	* sysdeps/generic/ifaddrs.c: New file.
+	* sysdeps/gnu/ifaddrs.c: New file.
+	* inet/test-ifaddrs.c: New file.
+	* inet/Makefile (routines): Add ifaddrs.
+	(headers): Add ifaddrs.h here.
+	(tests): Add test-ifaddrs.
+	* inet/Versions (GLIBC_2.3): New set, add getifaddrs and freeifaddrs.
+
+	* resolv/res_hconf.c (_res_hconf_reorder_addrs): Use an explicit
+	socket call to get an AF_INET socket, instead of using __opensock.
+	The SIOCGIFNETMASK ioctl will work only with a PF_INET socket.
+
+	* sysdeps/generic/ifreq.h (__ifreq): Take third argument SOCKFD,
+	if not -1 use it instead of calling __opensock.
+	* sysdeps/unix/sysv/linux/ifreq.h (__ifreq): Likewise.
+	* sysdeps/mach/hurd/ifreq.h (__ifreq): Take new argument and ignore it.
+	* resolv/res_hconf.c (_res_hconf_reorder_addrs): Pass new argument.
+
+	* sysdeps/mach/hurd/ifreq.h: New file.
+	* sysdeps/generic/ifreq.h (__if_freereq): Take second argument NUM_IFS.
+	* sysdeps/unix/sysv/linux/ifreq.h (__if_freereq): Likewise.
+	* resolv/res_hconf.c (_res_hconf_reorder_addrs): Update caller.
+
 	* libio/fileops.c (_IO_file_seekoff_mmap): Don't rely on FP->_offset,
 	which gets moved around.  Calculate size of mmap'd buffer instead.
 
diff --git a/inet/Makefile b/inet/Makefile
index ab922db4b6..be588d78b0 100644
--- a/inet/Makefile
+++ b/inet/Makefile
@@ -1,4 +1,4 @@
-# Copyright (C) 1991-1999, 2000, 2001 Free Software Foundation, Inc.
+# Copyright (C) 1991-1999,2000,01,02 Free Software Foundation, Inc.
 # This file is part of the GNU C Library.
 
 # The GNU C Library is free software; you can redistribute it and/or
@@ -24,7 +24,7 @@ subdir	:= inet
 headers	:= netinet/ether.h netinet/in.h netinet/in_systm.h \
 	   netinet/if_ether.h \
 	   netinet/tcp.h netinet/ip.h $(wildcard arpa/*.h protocols/*.h) \
-	   aliases.h netinet/ip6.h netinet/icmp6.h bits/in.h
+	   aliases.h ifaddrs.h netinet/ip6.h netinet/icmp6.h bits/in.h
 
 distribute := netgroup.h
 
@@ -45,10 +45,10 @@ routines := htonl htons		\
 	    rcmd rexec ruserpass \
 	    getnetgrent_r getnetgrent \
 	    getaliasent_r getaliasent getaliasname getaliasname_r \
-	    in6_addr getnameinfo if_index
+	    in6_addr getnameinfo if_index ifaddrs
 
 tests := htontest test_ifindex tst-ntoa tst-ether_aton tst-network \
-	 tst-gethnm
+	 tst-gethnm test-ifaddrs
 
 include ../Rules
 
diff --git a/inet/Versions b/inet/Versions
index eb3b13c9d2..0eb1e77838 100644
--- a/inet/Versions
+++ b/inet/Versions
@@ -64,6 +64,12 @@ libc {
     # r*
     rcmd_af; rexec_af; rresvport_af; ruserok_af;
   }
+  GLIBC_2.3 {
+    # f*
+    freeifaddrs;
+    # g*
+    getifaddrs;
+  }
   GLIBC_PRIVATE {
     # functions used in other libraries
     __internal_endnetgrent; __internal_getnetgrent_r;
diff --git a/inet/ifaddrs.h b/inet/ifaddrs.h
new file mode 100644
index 0000000000..ba6a1554b1
--- /dev/null
+++ b/inet/ifaddrs.h
@@ -0,0 +1,74 @@
+/* ifaddrs.h -- declarations for getting network interface addresses
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifndef _IFADDRS_H
+#define _IFADDRS_H	1
+
+#include <features.h>
+#include <sys/socket.h>
+
+__BEGIN_DECLS
+
+/* The `getifaddrs' function generates a linked list of these structures.
+   Each element of the list describes one network interface.  */
+struct ifaddrs
+{
+  struct ifaddrs *ifa_next;	/* Pointer to the next structure.  */
+
+  char *ifa_name;		/* Name of this network interface.  */
+  unsigned int ifa_flags;	/* Flags as from SIOCGIFFLAGS ioctl.  */
+
+  struct sockaddr *ifa_addr;	/* Network address of this interface.  */
+  struct sockaddr *ifa_netmask; /* Netmask of this interface.  */
+  union
+  {
+    /* At most one of the following two is valid.  If the IFF_BROADCAST
+       bit is set in `ifa_flags', then `ifa_broadaddr' is valid.  If the
+       IFF_POINTOPOINT bit is set, then `ifa_dstaddr' is valid.
+       It is never the case that both these bits are set at once.  */
+    struct sockaddr *ifu_broadaddr; /* Broadcast address of this interface. */
+    struct sockaddr *ifu_dstaddr; /* Point-to-point destination address.  */
+  } ifa_ifu;
+  /* These very same macros are defined by <net/if.h> for `struct ifaddr'.
+     So if they are defined already, the existing definitions will be fine.  */
+# ifndef ifa_broadaddr
+#  define ifa_broadaddr	ifa_ifu.ifu_broadaddr
+# endif
+# ifndef ifa_dstaddr
+#  define ifa_dstaddr	ifa_ifu.ifu_dstaddr
+# endif
+
+  void *ifa_data;		/* Address-specific data (may be unused).  */
+};
+
+
+/* Create a linked list of `struct ifaddrs' structures, one for each
+   network interface on the host machine.  If successful, store the
+   list in *IFAP and return 0.  On errors, return -1 and set `errno'.
+
+   The storage returned in *IFAP is allocated dynamically and can
+   only be properly freed by passing it to `freeifaddrs'.  */
+extern int getifaddrs (struct ifaddrs **__ifap) __THROW;
+
+/* Reclaim the storage allocated by a previous `getifaddrs' call.  */
+extern void freeifaddrs (struct ifaddrs *__ifa)  __THROW;
+
+__END_DECLS
+
+#endif /* ifaddrs.h */
diff --git a/inet/test-ifaddrs.c b/inet/test-ifaddrs.c
new file mode 100644
index 0000000000..42fb7e75bf
--- /dev/null
+++ b/inet/test-ifaddrs.c
@@ -0,0 +1,82 @@
+/* Test listing of network interface addresses.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ifaddrs.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+int
+main (void)
+{
+  int failures = 0;
+  struct ifaddrs *ifaces, *ifa;
+
+  if (getifaddrs (&ifaces) < 0)
+    {
+      if (errno != ENOSYS)
+	{
+	  printf ("Couldn't get any interfaces: %s.\n", strerror (errno));
+	  exit (1);
+	}
+      /* The function is simply not implemented.  */
+      exit (0);
+    }
+
+  puts ("\
+Name           Flags   Address         Netmask         Broadcast/Destination");
+
+  for (ifa = ifaces; ifa != NULL; ifa = ifa->ifa_next)
+    {
+      char abuf[64], mbuf[64], dbuf[64];
+      inline const char *addr_string (struct sockaddr *sa, char *buf)
+	{
+	  switch (sa->sa_family)
+	    {
+	    case AF_INET:
+	      return inet_ntop (AF_INET,
+				&((struct sockaddr_in *) sa)->sin_addr,
+				buf, sizeof abuf);
+	    case AF_INET6:
+	      return inet_ntop (AF_INET6,
+				&((struct sockaddr_in6 *) sa)->sin6_addr,
+				buf, sizeof abuf);
+	    case AF_UNSPEC:
+	      return "---";
+	    default:
+	      ++failures;
+	      printf ("sa_family=%d %08x\n", sa->sa_family,
+		      *(int*)&((struct sockaddr_in *) sa)->sin_addr.s_addr);
+	      return "<unexpected sockaddr family>";
+	    }
+	}
+      printf ("%-15s%#.4x  %-15s %-15s %-15s\n",
+	      ifa->ifa_name, ifa->ifa_flags,
+	      addr_string (ifa->ifa_addr, abuf),
+	      addr_string (ifa->ifa_netmask, mbuf),
+	      addr_string (ifa->ifa_broadaddr, dbuf));
+    }
+
+  freeifaddrs (ifaces);
+
+  return failures ? 1 : 0;
+}
diff --git a/resolv/res_hconf.c b/resolv/res_hconf.c
index e6faa6855e..b814f62dd3 100644
--- a/resolv/res_hconf.c
+++ b/resolv/res_hconf.c
@@ -538,7 +538,8 @@ _res_hconf_reorder_addrs (struct hostent *hp)
 
       num_ifs = 0;
 
-      sd = __opensock ();
+      /* The SIOCGIFNETMASK ioctl will only work on an AF_INET socket.  */
+      sd = __socket (AF_INET, SOCK_DGRAM, 0);
       if (sd < 0)
 	return;
 
@@ -546,7 +547,7 @@ _res_hconf_reorder_addrs (struct hostent *hp)
       __libc_lock_lock (lock);
 
       /* Get a list of interfaces.  */
-      __ifreq (&ifr, &num);
+      __ifreq (&ifr, &num, sd);
       if (!ifr)
 	goto cleanup;
 
@@ -577,7 +578,7 @@ _res_hconf_reorder_addrs (struct hostent *hp)
       ifaddrs = realloc (ifaddrs, num_ifs * sizeof (ifaddrs[0]));
 
     cleanup1:
-      __if_freereq (ifr);
+      __if_freereq (ifr, num);
 
     cleanup:
       /* Release lock, preserve error value, and close socket.  */
diff --git a/sysdeps/generic/ifaddrs.c b/sysdeps/generic/ifaddrs.c
new file mode 100644
index 0000000000..7b29aa111c
--- /dev/null
+++ b/sysdeps/generic/ifaddrs.c
@@ -0,0 +1,44 @@
+/* getifaddrs -- get names and addresses of all network interfaces
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <ifaddrs.h>
+#include <errno.h>
+#include <stdlib.h>
+
+/* Create a linked list of `struct ifaddrs' structures, one for each
+   network interface on the host machine.  If successful, store the
+   list in *IFAP and return 0.  On errors, return -1 and set `errno'.  */
+int
+getifaddrs (struct ifaddrs **ifap)
+{
+  __set_errno (ENOSYS);
+  return -1;
+}
+stub_warning (getifaddrs)
+
+void
+freeifaddrs (struct ifaddrs *ifa)
+{
+  if (ifa == NULL)
+    return;			/* a la free, why not? */
+
+  /* Can't be called properly if getifaddrs never succeeded.  */
+  abort ();
+}
+stub_warning (freeifaddrs)
diff --git a/sysdeps/generic/ifreq.h b/sysdeps/generic/ifreq.h
index 62f3dcfaf9..c96d1c8789 100644
--- a/sysdeps/generic/ifreq.h
+++ b/sysdeps/generic/ifreq.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 1999 Free Software Foundation, Inc.
+/* Copyright (C) 1999,2002 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Andreas Jaeger <aj@suse.de>.
 
@@ -26,15 +26,17 @@
 
 
 static inline void
-__ifreq (struct ifreq **ifreqs, int *num_ifs)
+__ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd)
 {
-  int fd = __opensock ();
+  int fd = sockfd;
   struct ifconf ifc;
   int rq_len;
   int nifs;
 # define RQ_IFS	4
 
   if (fd < 0)
+    fd = __opensock ();
+  if (fd < 0)
     {
       *num_ifs = 0;
       *ifreqs = NULL;
@@ -51,8 +53,9 @@ __ifreq (struct ifreq **ifreqs, int *num_ifs)
 	{
 	  if (ifc.ifc_buf)
 	    free (ifc.ifc_buf);
-	  
-	  __close (fd);
+
+	  if (fd != sockfd)
+	    __close (fd);
 	  *num_ifs = 0;
 	  *ifreqs = NULL;
 	  return;
@@ -63,7 +66,8 @@ __ifreq (struct ifreq **ifreqs, int *num_ifs)
 
   nifs = ifc.ifc_len / sizeof (struct ifreq);
 
-  __close (fd);
+  if (fd != sockfd)
+    __close (fd);
 
   *num_ifs = nifs;
   *ifreqs = realloc (ifc.ifc_buf, nifs * sizeof (struct ifreq));
@@ -71,7 +75,7 @@ __ifreq (struct ifreq **ifreqs, int *num_ifs)
 
 
 static inline void
-__if_freereq (struct ifreq *ifreqs)
+__if_freereq (struct ifreq *ifreqs, int num_ifs)
 {
   free (ifreqs);
 }
diff --git a/sysdeps/gnu/ifaddrs.c b/sysdeps/gnu/ifaddrs.c
new file mode 100644
index 0000000000..e0a5b424f0
--- /dev/null
+++ b/sysdeps/gnu/ifaddrs.c
@@ -0,0 +1,147 @@
+/* getifaddrs -- get names and addresses of all network interfaces
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <ifaddrs.h>
+#include <net/if.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <netinet/in.h>
+
+#include "ifreq.h"
+
+/* Create a linked list of `struct ifaddrs' structures, one for each
+   network interface on the host machine.  If successful, store the
+   list in *IFAP and return 0.  On errors, return -1 and set `errno'.  */
+int
+getifaddrs (struct ifaddrs **ifap)
+{
+  /* This implementation handles only IPv4 interfaces.
+     The various ioctls below will only work on an AF_INET socket.
+     Some different mechanism entirely must be used for IPv6.  */
+  int fd = __socket (AF_INET, SOCK_DGRAM, 0);
+  struct ifreq *ifreqs;
+  int nifs, i;
+
+  if (fd < 0)
+    return -1;
+
+  __ifreq (&ifreqs, &nifs, fd);
+  if (ifreqs == NULL)		/* XXX doesn't distinguish error vs none */
+    {
+      __close (fd);
+      return -1;
+    }
+
+  /* Now we have the list of interfaces and each one's address.
+     Put it into the expected format and fill in the remaining details.  */
+  if (nifs == 0)
+    *ifap = NULL;
+  else
+    {
+      struct
+      {
+	struct ifaddrs ia;
+	struct sockaddr addr, netmask, broadaddr;
+	char name[IF_NAMESIZE];
+      } *storage;
+
+      storage = malloc (nifs * sizeof storage[0]);
+      if (storage == NULL)
+	{
+	  __close (fd);
+	  __if_freereq (ifreqs, nifs);
+	  return -1;
+	}
+
+      i = 0;
+      do
+	{
+	  struct ifreq *const ifr = &ifreqs[i];
+
+	  /* Fill in all pointers to the storage we've already allocated.  */
+	  storage[i].ia.ifa_next = &storage[i + 1].ia;
+	  storage[i].ia.ifa_addr = &storage[i].addr;
+	  storage[i].ia.ifa_netmask = &storage[i].netmask;
+	  storage[i].ia.ifa_broadaddr = &storage[i].broadaddr; /* & dstaddr */
+
+	  /* Now copy the information we already have from SIOCGIFCONF.  */
+	  storage[i].ia.ifa_name = strncpy (storage[i].name, ifr->ifr_name,
+					    sizeof storage[i].name);
+	  storage[i].addr = ifr->ifr_addr;
+
+	  /* The SIOCGIFCONF call filled in only the name and address.
+	     Now we must also ask for the other information we need.  */
+
+	  if (__ioctl (fd, SIOCGIFFLAGS, ifr) < 0)
+	    break;
+	  storage[i].ia.ifa_flags = ifr->ifr_flags;
+
+	  ifr->ifr_addr = storage[i].addr;
+	  if (__ioctl (fd, SIOCGIFNETMASK, ifr) < 0)
+	    break;
+	  storage[i].netmask = ifr->ifr_netmask;
+
+	  if (ifr->ifr_flags & IFF_BROADCAST)
+	    {
+	      ifr->ifr_addr = storage[i].addr;
+	      if (__ioctl (fd, SIOCGIFBRDADDR, ifr) < 0)
+		break;
+	      storage[i].broadaddr = ifr->ifr_broadaddr;
+	    }
+	  else if (ifr->ifr_flags & IFF_POINTOPOINT)
+	    {
+	      ifr->ifr_addr = storage[i].addr;
+	      if (__ioctl (fd, SIOCGIFDSTADDR, ifr) < 0)
+		break;
+	      storage[i].broadaddr = ifr->ifr_dstaddr;
+	    }
+	  else
+	    /* Just 'cause.  */
+	    memset (&storage[i].broadaddr, 0, sizeof storage[i].broadaddr);
+
+	  storage[i].ia.ifa_data = NULL; /* Nothing here for now.  */
+
+	} while (++i < nifs);
+      if (i < nifs)		/* Broke out early on error.  */
+	{
+	  __close (fd);
+	  free (storage);
+	  __if_freereq (ifreqs, nifs);
+	  return -1;
+	}
+      storage[i - 1].ia.ifa_next = NULL;
+
+      *ifap = &storage[0].ia;
+
+      __close (fd);
+      __if_freereq (ifreqs, nifs);
+    }
+
+  return 0;
+}
+
+void
+freeifaddrs (struct ifaddrs *ifa)
+{
+  free (ifa);
+}
diff --git a/sysdeps/mach/hurd/ifreq.h b/sysdeps/mach/hurd/ifreq.h
new file mode 100644
index 0000000000..737dee9285
--- /dev/null
+++ b/sysdeps/mach/hurd/ifreq.h
@@ -0,0 +1,74 @@
+/* Fetch the host's network interface list.  Hurd version.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <net/if.h>
+#include <hurd.h>
+#include <hurd/pfinet.h>
+#include <sys/socket.h>
+#include <sys/mman.h>
+
+
+static inline void
+__ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd)
+{
+  struct ifconf ifc;
+  file_t server;
+
+  server = _hurd_socket_server (PF_INET, 0);
+  if (server == MACH_PORT_NULL)
+    {
+    out:
+      *num_ifs = 0;
+      *ifreqs = NULL;
+    }
+  else
+    {
+      char *data = NULL;
+      size_t len = 0;
+      error_t err = __pfinet_siocgifconf (server, -1, &data, &len);
+      if (err == MACH_SEND_INVALID_DEST || err == MIG_SERVER_DIED)
+	{
+	  /* On the first use of the socket server during the operation,
+	     allow for the old server port dying.  */
+	  server = _hurd_socket_server (PF_INET, 1);
+	  if (server == MACH_PORT_NULL)
+	    goto out;
+	  err = __pfinet_siocgifconf (server, -1, ifreqs, &len);
+	}
+      if (err)
+	goto out;
+
+      if (len % sizeof (struct ifreq) != 0)
+	{
+	  munmap (data, len);
+	  errno = EGRATUITOUS;
+	  goto out;
+	}
+      *num_ifs = len / sizeof (struct ifreq);
+      *ifreqs = (struct ifreq *) data;
+    }
+
+}
+
+
+static inline void
+__if_freereq (struct ifreq *ifreqs, int num_ifs)
+{
+  munmap (ifreqs, num_ifs * sizeof (struct ifreq))
+}
diff --git a/sysdeps/unix/sysv/linux/ifreq.h b/sysdeps/unix/sysv/linux/ifreq.h
index b38342534d..216c1f3373 100644
--- a/sysdeps/unix/sysv/linux/ifreq.h
+++ b/sysdeps/unix/sysv/linux/ifreq.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 1999 Free Software Foundation, Inc.
+/* Copyright (C) 1999,2002 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Andreas Jaeger <aj@suse.de>.
 
@@ -34,21 +34,23 @@ static int old_siocgifconf;
 
 
 static inline void
-__ifreq (struct ifreq **ifreqs, int *num_ifs)
+__ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd)
 {
-  int fd = __opensock ();
+  int fd = sockfd;
   struct ifconf ifc;
   int rq_len;
   int nifs;
 # define RQ_IFS	4
 
   if (fd < 0)
+    fd = __opensock ();
+  if (fd < 0)
     {
       *num_ifs = 0;
       *ifreqs = NULL;
       return;
     }
-  
+
   ifc.ifc_buf = NULL;
 
   /* We may be able to get the needed buffer size directly, rather than
@@ -79,8 +81,9 @@ __ifreq (struct ifreq **ifreqs, int *num_ifs)
 	{
 	  if (ifc.ifc_buf)
 	    free (ifc.ifc_buf);
-	  
-	  __close (fd);
+
+	  if (fd != sockfd)
+	    __close (fd);
 
 	  *num_ifs = 0;
 	  *ifreqs = NULL;
@@ -91,14 +94,16 @@ __ifreq (struct ifreq **ifreqs, int *num_ifs)
   while (ifc.ifc_len == rq_len && old_siocgifconf);
 
   nifs = ifc.ifc_len / sizeof (struct ifreq);
-  __close (fd);
+
+  if (fd != sockfd)
+    __close (fd);
 
   *num_ifs = nifs;
   *ifreqs = realloc (ifc.ifc_buf, nifs * sizeof (struct ifreq));
 }
 
 static inline void
-__if_freereq (struct ifreq *ifreqs)
+__if_freereq (struct ifreq *ifreqs, int num_ifs)
 {
   free (ifreqs);
 }