Use a realloc() loop around the sysctl() for NET_RT_IFLIST, in case an

interface is added at just the right... wrong moment.
ok millert dlg

1 files changed, 21 insertions, 9 deletions

diff --git a/src/lib/libc/net/getifaddrs.c b/src/lib/libc/net/getifaddrs.c
index 6f7ea15721..da42a23783 100644
--- a/src/lib/libc/net/getifaddrs.c
+++ b/src/lib/libc/net/getifaddrs.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: getifaddrs.c,v 1.10 2008/11/24 20:08:49 claudio Exp $ */
+/*      $OpenBSD: getifaddrs.c,v 1.11 2013/03/20 14:15:56 deraadt Exp $ */
 
 /*
  * Copyright (c) 1995, 1999
@@ -52,7 +52,7 @@ getifaddrs(struct ifaddrs **pif)
         int ncnt = 0;
         int mib[6];
         size_t needed;
-        char *buf;
+        char *buf = NULL, *bufp;
         char *next;
         struct ifaddrs *cif = 0;
         char *p, *p0;
@@ -74,13 +74,25 @@ getifaddrs(struct ifaddrs **pif)
         mib[3] = 0;             /* wildcard address family */
         mib[4] = NET_RT_IFLIST;
         mib[5] = 0;             /* no flags */
-        if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
-                return (-1);
-        if ((buf = malloc(needed)) == NULL)
-                return (-1);
-        if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
-                free(buf);
-                return (-1);
+        while (1) {
+                if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1) {
+                        free(buf);
+                        return (-1);
+                }
+                if (needed == 0)
+                        break;
+                if ((bufp = realloc(buf, needed)) == NULL) {
+                        free(buf);
+                        return (-1);
+                }
+                buf = bufp;
+                if (sysctl(mib, 6, buf, &needed, NULL, 0) == -1) {
+                        if (errno == ENOMEM)
+                                continue;
+                        free(buf);
+                        return (-1);
+                }
+                break;
         }
 
         for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {