From fc3034ca7d6516ccdd952217b34e8a1cc8654650 Mon Sep 17 00:00:00 2001
From: Brian Somers <brian@FreeBSD.org>
Date: Wed, 22 Sep 1999 00:40:47 +0000
Subject: [PATCH] Do a kldload() if we get ENXIO trying to open /dev/tun0

Originally submitted by: green
---
 usr.sbin/ppp/bundle.c | 29 +++++++++++++++++++++++++++++
 usr.sbin/ppp/id.c     | 19 ++++++++++++++++++-
 usr.sbin/ppp/id.h     |  3 +++
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/usr.sbin/ppp/bundle.c b/usr.sbin/ppp/bundle.c
index 072b5c384618..822f13ce0480 100644
--- a/usr.sbin/ppp/bundle.c
+++ b/usr.sbin/ppp/bundle.c
@@ -45,6 +45,9 @@
 #include <string.h>
 #include <sys/uio.h>
 #include <sys/wait.h>
+#if defined(__FreeBSD__) && !defined(NOKLDLOAD)
+#include <sys/linker.h>
+#endif
 #include <termios.h>
 #include <unistd.h>
 
@@ -601,6 +604,9 @@ bundle_Create(const char *prefix, int type, const char **argv)
   static struct bundle bundle;		/* there can be only one */
   int enoentcount, err;
   const char *ifname;
+#ifdef KLDSYM_LOOKUP
+  int kldtried;
+#endif
 #if defined(TUNSIFMODE) || defined(TUNSLMODE)
   int iff;
 #endif
@@ -612,6 +618,9 @@ bundle_Create(const char *prefix, int type, const char **argv)
 
   err = ENOENT;
   enoentcount = 0;
+#ifdef KLDSYM_LOOKUP
+  kldtried = 0;
+#endif
   for (bundle.unit = 0; ; bundle.unit++) {
     snprintf(bundle.dev.Name, sizeof bundle.dev.Name, "%s%d",
              prefix, bundle.unit);
@@ -619,6 +628,26 @@ bundle_Create(const char *prefix, int type, const char **argv)
     if (bundle.dev.fd >= 0)
       break;
     else if (errno == ENXIO) {
+#ifdef KLDSYM_LOOKUP
+      if (bundle.unit == 0 && !kldtried++) {
+        /*
+         * XXX:  For some odd reason, FreeBSD (right now) allows if_tun.ko to
+         *       load even when the kernel contains the tun device. This lookup
+         *       should go away when this is fixed, leaving just the kldload().
+         * Note also that kldsym() finds static symbols...
+         */
+        char devsw[] = "tun_cdevsw";
+        struct kld_sym_lookup ksl = { sizeof ksl, devsw, 0, 0 };
+
+        if (kldsym(0, KLDSYM_LOOKUP, &ksl) == -1) {
+          if (ID0kldload("if_tun") != -1) {
+            bundle.unit--;
+            continue;
+          }
+          log_Printf(LogWARN, "kldload: if_tun: %s\n", strerror(errno));
+        }
+      }
+#endif
       err = errno;
       break;
     } else if (errno == ENOENT) {
diff --git a/usr.sbin/ppp/id.c b/usr.sbin/ppp/id.c
index 4aaba3714417..79dec7209d3c 100644
--- a/usr.sbin/ppp/id.c
+++ b/usr.sbin/ppp/id.c
@@ -26,7 +26,7 @@
  * $FreeBSD$
  */
 
-#include <sys/types.h>
+#include <sys/param.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 
@@ -37,6 +37,9 @@
 #include <stdio.h>
 #include <string.h>
 #include <sysexits.h>
+#if defined(__FreeBSD__) && !defined(NOKLDLOAD)
+#include <sys/linker.h>
+#endif
 #include <unistd.h>
 #ifdef __OpenBSD__
 #include <util.h>
@@ -265,3 +268,17 @@ ID0kill(pid_t pid, int sig)
   ID0setuser();
   return result;
 }
+
+#ifdef KLDSYM_LOOKUP
+int
+ID0kldload(const char *dev)
+{
+  int result;
+
+  ID0set0();
+  result = kldload(dev);
+  log_Printf(LogID0, "%d = kldload(\"%s\")\n", result, dev);
+  ID0setuser();
+  return result;
+}
+#endif
diff --git a/usr.sbin/ppp/id.h b/usr.sbin/ppp/id.h
index 18b1f44a2991..ddf0d7c2e883 100644
--- a/usr.sbin/ppp/id.h
+++ b/usr.sbin/ppp/id.h
@@ -45,3 +45,6 @@ extern void ID0logout(const char *);
 extern int ID0bind_un(int, const struct sockaddr_un *);
 extern int ID0connect_un(int, const struct sockaddr_un *);
 extern int ID0kill(pid_t, int);
+#ifdef KLDSYM_LOOKUP
+extern int ID0kldload(const char *);
+#endif