Pass an error message through to sshfwd_unclean_close.

We have access to one at every call site, so there's really no reason
not to send it through to ssh.c to be logged.

[originally from svn r10038]

portfwd.c

@@ -88,7 +88,7 @@ static int pfd_closing(Plug plug, const char *error_msg, int error_code,
          * Socket error. Slam the connection instantly shut.
          */
         if (pr->c) {
-            sshfwd_unclean_close(pr->c);
+            sshfwd_unclean_close(pr->c, error_msg);
         } else {
             /*
              * We might not have an SSH channel, if a socket error

ssh.c

@@ -4302,7 +4302,7 @@ void sshfwd_write_eof(struct ssh_channel *c)
     ssh_channel_try_eof(c);
 }
 
-void sshfwd_unclean_close(struct ssh_channel *c)
+void sshfwd_unclean_close(struct ssh_channel *c, const char *err)
 {
     Ssh ssh = c->ssh;
 
@@ -4312,12 +4312,13 @@ void sshfwd_unclean_close(struct ssh_channel *c)
     switch (c->type) {
       case CHAN_X11:
         x11_close(c->u.x11.s);
-        logevent("Forwarded X11 connection terminated due to local error");
+        logeventf(ssh, "Forwarded X11 connection terminated due to local "
+                  "error: %s", err);
         break;
       case CHAN_SOCKDATA:
       case CHAN_SOCKDATA_DORMANT:
         pfd_close(c->u.pfd.s);
-        logevent("Forwarded port closed due to local error");
+        logeventf(ssh, "Forwarded port closed due to local error: %s", err);
         break;
     }
     c->type = CHAN_ZOMBIE;

ssh.h

@@ -11,7 +11,7 @@ struct ssh_channel;
 
 extern int sshfwd_write(struct ssh_channel *c, char *, int);
 extern void sshfwd_write_eof(struct ssh_channel *c);
-extern void sshfwd_unclean_close(struct ssh_channel *c);
+extern void sshfwd_unclean_close(struct ssh_channel *c, const char *err);
 extern void sshfwd_unthrottle(struct ssh_channel *c, int bufsize);
 
 /*

x11fwd.c

@@ -510,7 +510,7 @@ static int x11_closing(Plug plug, const char *error_msg, int error_code,
         /*
          * Socket error. Slam the connection instantly shut.
          */
-        sshfwd_unclean_close(pr->c);
+        sshfwd_unclean_close(pr->c, error_msg);
     } else {
         /*
          * Ordinary EOF received on socket. Send an EOF on the SSH