$NetBSD: patch-ae,v 1.3 2009/02/11 08:06:17 obache Exp $

--- getifname.c.orig	2004-05-03 08:55:53.000000000 +0000
+++ getifname.c
@@ -17,7 +17,7 @@
 #include <unistd.h>		/* close */
 
 #if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || \
-    defined(__bsdi__) || defined(__APPLE__)
+    defined(__bsdi__) || defined(__APPLE__) || defined(__DragonFly__)
 #include <stdlib.h>
 #include <ifaddrs.h>
 #include <net/route.h>
@@ -27,12 +27,12 @@
 #include "globals.h"
 
 #if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && \
-    !defined(__linux__) && !defined(__sun__) && !defined(__bsdi__) && \
-    !defined(__APPLE__)
+    !defined(__linux__) && !defined(__sun) && !defined(__bsdi__) && \
+    !defined(__APPLE__) && !defined(__DragonFly__)
 #error Sorry, interface code not implemented.
 #endif
 
-#ifdef __sun__
+#ifdef __sun
 #include <sys/sockio.h>
 #include <net/route.h>
 #include <net/if_dl.h>
@@ -40,15 +40,16 @@
 
 static int get_output_if(struct sockaddr_in *dest, struct sockaddr_in *ifip);
 
-#if (defined OSTYPE_LINUX) || (defined __sun__)
+#if (defined OSTYPE_LINUX) || (defined __sun)
 int get_if_name(void)
 {
 	int fd;
 	struct ifconf	ifc;
-	struct ifreq	ibuf[16],
-			ifr,
+	struct ifreq	ifr,
 			*ifrp,
 			*ifend;
+	char *ibuf;
+	int ibuflen;
 	struct sockaddr_in sa;
 	struct sockaddr_in output_if_addr;
 	int known_output_if = 0;
@@ -72,21 +73,40 @@ int get_if_name(void)
 		return -1;
 	}
 
-	memset(ibuf, 0, sizeof(struct ifreq)*16);
-	ifc.ifc_len = sizeof ibuf;
+	ibuf = NULL;
+	ibuflen = 16 * sizeof(struct ifreq);
+	for (;;) {
+		char *nibuf = (char *) realloc(ibuf, ibuflen);
+		if (!nibuf) {
+			perror("[get_if_name] realloc");
+			goto go_out;
+		}
+
+		ibuf = nibuf;
+		memset(ibuf, 0, ibuflen);
+		ifc.ifc_len = ibuflen;
 	ifc.ifc_buf = (caddr_t) ibuf;
 
 	/* gets interfaces list */
 	if ( ioctl(fd, SIOCGIFCONF, (char*)&ifc) == -1 ||
 	     ifc.ifc_len < sizeof(struct ifreq)		) {
 		perror("[get_if_name] ioctl(SIOCGIFCONF)");
-		close(fd);
-		return -1;
+			goto go_out;
+		}
+
+		if (ifc.ifc_len + sizeof(struct ifreq) <= ibuflen)
+			break;
+		if (ibuflen >= 1024 * sizeof(struct ifreq)) {
+			fprintf(stderr, "Warning: Too many network "
+					"interfaces.\n");
+			break;
+		}
+		ibuflen *= 2;
 	}
 
 	/* ifrp points to buffer and ifend points to buffer's end */
-	ifrp = ibuf;
-	ifend = (struct ifreq*) ((char*)ibuf + ifc.ifc_len);
+	ifrp = (struct ifreq *) ibuf;
+	ifend = (struct ifreq *) (ibuf + ifc.ifc_len);
 
 	for (; ifrp < ifend; ifrp++) {
 		strlcpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifr.ifr_name));
@@ -155,27 +175,28 @@ int get_if_name(void)
 		}
 		else
 		{
-#ifdef __sun__
+#ifdef __sun
 			/* somehow solaris is braidamaged in wrt ifr_mtu */
 			h_if_mtu = ifr.ifr_metric;
 #else
 			h_if_mtu = ifr.ifr_mtu;
 #endif
 		}
-		close(fd);
-		return 0;
+		goto go_out;
 	}
 	/* interface not found, use 'lo' */
 	strlcpy(ifname, "lo", 1024);
 	strlcpy(ifstraddr, "127.0.0.1", 1024);
 	h_if_mtu = 1500;
 
+go_out:
+	free(ibuf);
 	close(fd);
 	return 0;
 }
 
 #elif defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || \
-      defined(__bsdi__) || defined(__APPLE__)
+      defined(__bsdi__) || defined(__APPLE__) || defined(__DragonFly__)
 
 /* return interface informations :
    - from the specified (-I) interface