--- ircservices-5.1a5/extern.h	Tue Jan 24 00:04:52 2006
+++ ircservices-5.1a5.patch/extern.h	Mon Jan 30 18:34:14 2006
@@ -306,7 +306,9 @@
 E void split_usermask(const char *mask, char **nick, char **user, char **host);
 E char *create_mask(User *u, int use_fakehost);
 
-E char *make_guest_nick(void);
+E char *make_guest_nick(const char *nick);
+E char *format_guestprefix(const char *format, const char *nick);
+
 E int is_guest_nick(const char *nick);
 
 
--- ircservices-5.1a5/modules/nickserv/collide.c	Tue Jan 24 00:04:54 2006
+++ ircservices-5.1a5.patch/modules/nickserv/collide.c	Mon Jan 30 18:39:11 2006
@@ -48,7 +48,7 @@
     if (call_callback_1(cb_collide, ni->user) > 0)
         return;
     if (NSForceNickChange) {
-        char *guestnick = make_guest_nick();
+        char *guestnick = make_guest_nick(ni->nick);
         notice_lang(s_NickServ, ni->user, FORCENICKCHANGE_NOW, guestnick);
         send_nickchange_remote(ni->nick, guestnick);
         ni->status |= NS_GUESTED;
--- ircservices-5.1a5/modules/operserv/sline.c	Tue Jan 24 00:04:54 2006
+++ ircservices-5.1a5.patch/modules/operserv/sline.c	Mon Jan 30 18:39:54 2006
@@ -135,7 +135,7 @@
             if (!SQlineKill && (protocol_features & PF_CHANGENICK)) {
                 send_cmd(ServerName, "432 %s %s Invalid nickname (%s)",
                          nick, nick, reason);
-                send_nickchange_remote(nick, make_guest_nick());
+                send_nickchange_remote(nick, make_guest_nick(nick));
             } else {
                 /* User is to be killed */
                 retval = reason;
--- ircservices-5.1a5/users.c	Tue Jan 24 00:04:53 2006
+++ ircservices-5.1a5.patch/users.c	Mon Jan 30 18:59:49 2006
@@ -832,7 +832,7 @@
  * restarted.
  */
 
-char *make_guest_nick(void)
+char *make_guest_nick(const char *nick)
 {
     static char nickbuf[NICKMAX+1];     /* +1 to check for overrun */
     static uint32 counter = 0;          /* Unique suffix counter */
@@ -841,8 +841,10 @@
     uint32 suffixmod;                   /* Modulo for suffix counter */
     int i;
 
+    char *p_GuestNickPrefix = format_guestprefix(GuestNickPrefix, nick);
+
     /* Sanity checks on nick prefix length */
-    prefixlen = strlen(GuestNickPrefix);
+    prefixlen = strlen(p_GuestNickPrefix);
     if (protocol_nickmax <= 4) {
         /* This violates RFC1459 as well as common sense, so just blow
          * ourselves out of the water. */
@@ -851,9 +853,9 @@
     } else if (prefixlen+4 > protocol_nickmax) {
         /* Reserve at least 4 digits for the suffix */
         prefixlen = protocol_nickmax-4;
-        log("warning: make_guest_nick(): GuestNickPrefix too long,"
+        log("warning: make_guest_nick(): p_GuestNickPrefix too long,"
             " shortening to %d characters", prefixlen);
-        GuestNickPrefix[prefixlen] = 0;
+        p_GuestNickPrefix[prefixlen] = 0;
     }
 
     /* Calculate number of digits available for suffix -> suffix modulo */
@@ -878,7 +880,7 @@
             counter %= suffixmod;
         if (counter == 0)       /* if rand() gave us 0 or N*suffixmod... */
             counter = 1;        /* ... use 1 instead */
-        i = snprintf(nickbuf, sizeof(nickbuf), "%s%u", GuestNickPrefix, counter);
+        i = snprintf(nickbuf, sizeof(nickbuf), "%s%u", p_GuestNickPrefix, counter);
         if (i > protocol_nickmax) {
             log("BUG: make_guest_nick() generated %s but nickmax == %d!",
                 nickbuf, protocol_nickmax);
@@ -904,6 +906,38 @@
     /* Return the nick */
     return nickbuf;
 };
+
+/* Create and return the nickname for the given nick and format
+ * string. The nickname will be truncated at protocol_nickmax-1 bytes.
+ * The nickname is returned in a static buffer, and will be overwritten
+ * by subsequent calls.
+ */
+
+char *format_guestprefix(const char *format, const char *nick)
+{
+    static char guestnick[NICKMAX-4];
+    char *s;
+    int nick_guestnick_len = -1;
+
+    s = guestnick;
+    while (*format && s-guestnick < sizeof(guestnick)-1) {
+        if (*format == '%' && format[1] == 's') {
+            int left = (sizeof(guestnick)-1) - (s-guestnick);
+            if (nick_guestnick_len < 0)
+                nick_guestnick_len = strlen(nick);
+            if (left > nick_guestnick_len)
+                left = nick_guestnick_len;
+            memcpy(s, nick, left);
+            s += left;
+            format += 2;
+        } else {
+            *s++ = *format++;
+        }
+    }
+    *s = 0;
+    return guestnick;
+}
+
 
 /*************************************************************************/