Fix changes to interface list during getifaddrs calls.

ChangeLog

@@ -1,3 +1,13 @@
+2010-04-03  Ulrich Drepper  <drepper@redhat.com>
+
+	[BZ #11387]
+	* sysdeps/unix/sysv/linux/ifaddrs.c (map_newlin): Don't abort on
+	unknown interface, return -1.
+	(getifaddrs_internal): Rename from getifaddrs.  Handle errors in
+	map_newlink be returning -EAGAIN.
+	(getifaddrs): If -EAGAIN is returned from getifaddrs_internal try
+	again.
+
 2010-03-25  Ryan S. Arnold  <rsa@us.ibm.com>
 
 	* sysdeps/unix/sysv/linux/getsysstats.c (next_line): Remove

sysdeps/unix/sysv/linux/ifaddrs.c

@@ -1,5 +1,5 @@
 /* getifaddrs -- get names and addresses of all network interfaces
-   Copyright (C) 2003-2008, 2009 Free Software Foundation, Inc.
+   Copyright (C) 2003-2008, 2009, 2010 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
@@ -315,17 +315,19 @@ map_newlink (int index, struct ifaddrs_storage *ifas, int *map, int max)
       else if (map[i] == index)
 	return i;
     }
-  /* This should never be reached. If this will be reached, we have
+
-     a very big problem.  */
+  /* This means interfaces changed inbetween the reading of the
-  abort ();
+     RTM_GETLINK and RTM_GETADDR information.  We have to repeat
+     everything.  */
+  return -1;
 }
 
 
 /* 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
+static int
-getifaddrs (struct ifaddrs **ifap)
+getifaddrs_internal (struct ifaddrs **ifap)
 {
   struct netlink_handle nh = { 0, 0, 0, NULL, NULL };
   struct netlink_res *nlp;
@@ -481,6 +483,13 @@ getifaddrs (struct ifaddrs **ifap)
 		 kernel.  */
 	      ifa_index = map_newlink (ifim->ifi_index - 1, ifas,
 				       map_newlink_data, newlink);
+	      if (__builtin_expect (ifa_index == -1, 0))
+		{
+		try_again:
+		  result = -EAGAIN;
+		  free (ifas);
+		  goto exit_free;
+		}
 	      ifas[ifa_index].ifa.ifa_flags = ifim->ifi_flags;
 
 	      while (RTA_OK (rta, rtasize))
@@ -565,9 +574,11 @@ getifaddrs (struct ifaddrs **ifap)
 		 that we have holes in the interface part of the list,
 		 but we always have already the interface for this address.  */
 	      ifa_index = newlink + newaddr_idx;
-	      ifas[ifa_index].ifa.ifa_flags
+	      int idx = map_newlink (ifam->ifa_index - 1, ifas,
-		= ifas[map_newlink (ifam->ifa_index - 1, ifas,
+				     map_newlink_data, newlink);
-				    map_newlink_data, newlink)].ifa.ifa_flags;
+	      if (__builtin_expect (idx == -1, 0))
+		goto try_again;
+	      ifas[ifa_index].ifa.ifa_flags = ifas[idx].ifa.ifa_flags;
 	      if (ifa_index > 0)
 		ifas[ifa_index - 1].ifa.ifa_next = &ifas[ifa_index].ifa;
 	      ++newaddr_idx;
@@ -747,9 +758,13 @@ getifaddrs (struct ifaddrs **ifap)
 	      /* If we didn't get the interface name with the
 		 address, use the name from the interface entry.  */
 	      if (ifas[ifa_index].ifa.ifa_name == NULL)
-		ifas[ifa_index].ifa.ifa_name
+		{
-		  = ifas[map_newlink (ifam->ifa_index - 1, ifas,
+		  int idx = map_newlink (ifam->ifa_index - 1, ifas,
-				      map_newlink_data, newlink)].ifa.ifa_name;
+					 map_newlink_data, newlink);
+		  if (__builtin_expect (idx == -1, 0))
+		    goto try_again;
+		  ifas[ifa_index].ifa.ifa_name = ifas[idx].ifa.ifa_name;
+		}
 
 	      /* Calculate the netmask.  */
 	      if (ifas[ifa_index].ifa.ifa_addr
@@ -826,6 +841,22 @@ getifaddrs (struct ifaddrs **ifap)
 
   return result;
 }
+
+
+/* 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)
+{
+  int res;
+
+  do
+    res = getifaddrs_internal (ifap);
+  while (res == -EAGAIN);
+
+  return res;
+}
 libc_hidden_def (getifaddrs)