Index: cyrus-imapd-2.3.9/imap/cyr_expire.c
===================================================================
--- cyrus-imapd-2.3.9.orig/imap/cyr_expire.c	2007-09-02 08:05:41.000000000 -0400
+++ cyrus-imapd-2.3.9/imap/cyr_expire.c	2007-09-02 08:06:39.000000000 -0400
@@ -75,7 +75,7 @@
 void usage(void)
 {
     fprintf(stderr,
-	    "cyr_expire [-C <altconfig>] -E <days> [-X <expunge-days>] [-a] [-v]\n");
+	    "cyr_expire [-C <altconfig>] -E <days> [-X <expunge-days>] [-p prefix] [-a] [-v]\n");
     exit(-1);
 }
 
@@ -350,6 +350,7 @@
     extern char *optarg;
     int opt, r = 0, expire_days = 0, expunge_days = 0, delete_days = 0;
     char *alt_config = NULL;
+    char *find_prefix = NULL;
     char buf[100];
     struct hash_table expire_table;
     struct expire_rock erock;
@@ -364,7 +365,7 @@
     memset(&erock, 0, sizeof(erock));
     memset(&drock, 0, sizeof(drock));
 
-    while ((opt = getopt(argc, argv, "C:D:E:X:va")) != EOF) {
+    while ((opt = getopt(argc, argv, "C:D:E:X:p:va")) != EOF) {
 	switch (opt) {
 	case 'C': /* alt config file */
 	    alt_config = optarg;
@@ -385,6 +386,10 @@
 	    expunge_days = atoi(optarg);
 	    break;
 
+	case 'p':
+	    find_prefix = optarg;
+	    break;
+
 	case 'v':
 	    erock.verbose++;
 	    drock.verbose++;
@@ -438,7 +443,11 @@
 		expunge_days);
     }
 
-    strlcpy(buf, "*", sizeof(buf));
+    if (find_prefix) {
+	strlcpy(buf, find_prefix, sizeof(buf));
+    } else {
+	strlcpy(buf, "*", sizeof(buf));
+    }
     mboxlist_findall(NULL, buf, 1, 0, 0, &expire, &erock);
 
     syslog(LOG_NOTICE, "expunged %lu out of %lu messages from %lu mailboxes",
Index: cyrus-imapd-2.3.9/imap/mailbox.c
===================================================================
--- cyrus-imapd-2.3.9.orig/imap/mailbox.c	2007-09-02 08:05:40.000000000 -0400
+++ cyrus-imapd-2.3.9/imap/mailbox.c	2007-09-02 09:27:50.000000000 -0400
@@ -1938,6 +1938,12 @@
 	    cacheitembegin = cacheitem = mailbox->cache_base + cache_offset;
 	    for (cache_ent = 0; cache_ent < NUM_CACHE_FIELDS; cache_ent++) {
 		cacheitem = CACHE_ITEM_NEXT(cacheitem);
+		if ((cacheitem < (mailbox->cache_base + cache_offset)) || 
+		    (cacheitem > (mailbox->cache_base + mailbox->cache_len))) {
+		    syslog(LOG_ERR, "IOERROR: reading cache record for %s: got bogus offset %d for %u/%lu; try reconstruct",
+				 mailbox->name, cacheitem - (mailbox->cache_base + cache_offset), msgno, mailbox->exists);
+		    return IMAP_IOERROR;
+		}
 	    }
 	    cache_record_size = (cacheitem - cacheitembegin);
 	    *new_cache_total_size += cache_record_size;
Index: cyrus-imapd-2.3.9/man/cyr_expire.8
===================================================================
--- cyrus-imapd-2.3.9.orig/man/cyr_expire.8	2007-09-02 08:05:40.000000000 -0400
+++ cyrus-imapd-2.3.9/man/cyr_expire.8	2007-09-02 08:06:39.000000000 -0400
@@ -56,6 +56,9 @@
 .BI \-X " expunge-days"
 ]
 [
+.B \-p " mailbox-prefix"
+]
+[
 .B \-v
 ]
 .SH DESCRIPTION
@@ -102,6 +105,10 @@
 (when using the "delayed" expunge mode).  The default is 0 (zero)
 days, which will expunge \fBall\fR previously deleted messages.
 .TP
+\fB\-p \fImailbox-prefix\fR
+Only find mailboxes starting with this prefix.  e.g.
+"user.justgotspammedlots"
+.TP
 .B \-v
 Enable verbose output.
 .TP