--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/osdep/amiga/mix.c	Mon Sep 14 15:17:45 2009 +0900
@@ -0,0 +1,2834 @@
+/* ========================================================================
+ * Copyright 1988-2008 University of Washington
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 
+ * ========================================================================
+ */
+
+/*
+ * Program:	MIX mail routines
+ *
+ * Author(s):	Mark Crispin
+ *		UW Technology
+ *		University of Washington
+ *		Seattle, WA  98195
+ *		Internet: MRC@Washington.EDU
+ *
+ * Date:	1 March 2006
+ * Last Edited:	7 May 2008
+ */
+
+
+#include <stdio.h>
+#include <ctype.h>
+#include <errno.h>
+extern int errno;		/* just in case */
+#include "mail.h"
+#include "osdep.h"
+#include <pwd.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include "misc.h"
+#include "dummy.h"
+#include "fdstring.h"
+
+/* MIX definitions */
+
+#define MEGABYTE (1024*1024)
+
+#define MIXDATAROLL MEGABYTE	/* size at which we roll to a new file */
+
+
+/* MIX files */
+
+#define MIXNAME ".mix"		/* prefix for all MIX file names */
+#define MIXMETA "meta"		/* suffix for metadata */
+#define MIXINDEX "index"	/* suffix for index */
+#define MIXSTATUS "status"	/* suffix for status */
+#define MIXSORTCACHE "sortcache"/* suffix for sortcache */
+#define METAMAX (MEGABYTE-1)	/* maximum metadata file size (sanity check) */
+
+
+/* MIX file formats */
+
+				/* sequence format (all but msg files) */
+#define SEQFMT "S%08lx\015\012"
+				/* metadata file format */
+#define MTAFMT "V%08lx\015\012L%08lx\015\012N%08lx\015\012"
+				/* index file record format */
+#define IXRFMT ":%08lx:%04d%02d%02d%02d%02d%02d%c%02d%02d:%08lx:%08lx:%08lx:%08lx:%08lx:\015\012"
+				/* status file record format */
+#define STRFMT ":%08lx:%08lx:%04x:%08lx:\015\012"
+				/* message file header format */
+#define MSRFMT "%s%08lx:%04d%02d%02d%02d%02d%02d%c%02d%02d:%08lx:\015\012"
+#define MSGTOK ":msg:"
+#define MSGTSZ (sizeof(MSGTOK)-1)
+				/* sortcache file record format */
+#define SCRFMT ":%08lx:%08lx:%08lx:%08lx:%08lx:%c%08lx:%08lx:%08lx:\015\012"
+
+/* MIX I/O stream local data */
+	
+typedef struct mix_local {
+  unsigned long curmsg;		/* current message file number */
+  unsigned long newmsg;		/* current new message file number */
+  time_t lastsnarf;		/* last snarf time */
+  int msgfd;			/* file description of current msg file */
+  int mfd;			/* file descriptor of open metadata */
+  unsigned long metaseq;	/* metadata sequence */
+  char *index;			/* mailbox index name */
+  unsigned long indexseq;	/* index sequence */
+  char *status;			/* mailbox status name */
+  unsigned long statusseq;	/* status sequence */
+  char *sortcache;		/* mailbox sortcache name */
+  unsigned long sortcacheseq;	/* sortcache sequence */
+  unsigned char *buf;		/* temporary buffer */
+  unsigned long buflen;		/* current size of temporary buffer */
+  unsigned int expok : 1;	/* non-zero if expunge reports OK */
+  unsigned int internal : 1;	/* internally opened, do not validate */
+} MIXLOCAL;
+
+
+#define MIXBURP struct mix_burp
+
+MIXBURP {
+  unsigned long fileno;		/* message file number */
+  char *name;			/* message file name */
+  SEARCHSET *tail;		/* tail of ranges */
+  SEARCHSET set;		/* set of retained ranges */
+  MIXBURP *next;		/* next file to burp */
+};
+
+
+/* Convenient access to local data */
+
+#define LOCAL ((MIXLOCAL *) stream->local)
+
+/* Function prototypes */
+
+DRIVER *mix_valid (char *name);
+long mix_isvalid (char *name,char *meta);
+void *mix_parameters (long function,void *value);
+long mix_dirfmttest (char *name);
+void mix_scan (MAILSTREAM *stream,char *ref,char *pat,char *contents);
+long mix_scan_contents (char *name,char *contents,unsigned long csiz,
+			unsigned long fsiz);
+void mix_list (MAILSTREAM *stream,char *ref,char *pat);
+void mix_lsub (MAILSTREAM *stream,char *ref,char *pat);
+long mix_subscribe (MAILSTREAM *stream,char *mailbox);
+long mix_unsubscribe (MAILSTREAM *stream,char *mailbox);
+long mix_create (MAILSTREAM *stream,char *mailbox);
+long mix_delete (MAILSTREAM *stream,char *mailbox);
+long mix_rename (MAILSTREAM *stream,char *old,char *newname);
+int mix_rselect (struct direct *name);
+MAILSTREAM *mix_open (MAILSTREAM *stream);
+void mix_close (MAILSTREAM *stream,long options);
+void mix_abort (MAILSTREAM *stream);
+char *mix_header (MAILSTREAM *stream,unsigned long msgno,unsigned long *length,
+		  long flags);
+long mix_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags);
+void mix_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags);
+unsigned long *mix_sort (MAILSTREAM *stream,char *charset,SEARCHPGM *spg,
+			 SORTPGM *pgm,long flags);
+THREADNODE *mix_thread (MAILSTREAM *stream,char *type,char *charset,
+			SEARCHPGM *spg,long flags);
+long mix_ping (MAILSTREAM *stream);
+void mix_check (MAILSTREAM *stream);
+long mix_expunge (MAILSTREAM *stream,char *sequence,long options);
+int mix_select (struct direct *name);
+int mix_msgfsort (const void *d1,const void *d2);
+long mix_addset (SEARCHSET **set,unsigned long start,unsigned long size);
+long mix_burp (MAILSTREAM *stream,MIXBURP *burp,unsigned long *reclaimed);
+long mix_burp_check (SEARCHSET *set,size_t size,char *file);
+long mix_copy (MAILSTREAM *stream,char *sequence,char *mailbox,
+	       long options);
+long mix_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data);
+long mix_append_msg (MAILSTREAM *stream,FILE *f,char *flags,MESSAGECACHE *delt,
+		     STRING *msg,SEARCHSET *set,unsigned long seq);
+
+FILE *mix_parse (MAILSTREAM *stream,FILE **idxf,long iflags,long sflags);
+char *mix_meta_slurp (MAILSTREAM *stream,unsigned long *seq);
+long mix_meta_update (MAILSTREAM *stream);
+long mix_index_update (MAILSTREAM *stream,FILE *idxf,long flag);
+long mix_status_update (MAILSTREAM *stream,FILE *statf,long flag);
+FILE *mix_data_open (MAILSTREAM *stream,int *fd,long *size,
+		     unsigned long newsize);
+FILE *mix_sortcache_open (MAILSTREAM *stream);
+long mix_sortcache_update (MAILSTREAM *stream,FILE **sortcache);
+char *mix_read_record (FILE *f,char *buf,unsigned long buflen,char *type);
+unsigned long mix_read_sequence (FILE *f);
+char *mix_dir (char *dst,char *name);
+char *mix_file (char *dst,char *dir,char *name);
+char *mix_file_data (char *dst,char *dir,unsigned long data);
+unsigned long mix_modseq (unsigned long oldseq);
+
+/* MIX mail routines */
+
+
+/* Driver dispatch used by MAIL */
+
+DRIVER mixdriver = {
+  "mix",			/* driver name */
+				/* driver flags */
+  DR_MAIL|DR_LOCAL|DR_NOFAST|DR_CRLF|DR_LOCKING|DR_DIRFMT|DR_MODSEQ,
+  (DRIVER *) NIL,		/* next driver */
+  mix_valid,			/* mailbox is valid for us */
+  mix_parameters,		/* manipulate parameters */
+  mix_scan,			/* scan mailboxes */
+  mix_list,			/* find mailboxes */
+  mix_lsub,			/* find subscribed mailboxes */
+  mix_subscribe,		/* subscribe to mailbox */
+  mix_unsubscribe,		/* unsubscribe from mailbox */
+  mix_create,			/* create mailbox */
+  mix_delete,			/* delete mailbox */
+  mix_rename,			/* rename mailbox */
+  mail_status_default,		/* status of mailbox */
+  mix_open,			/* open mailbox */
+  mix_close,			/* close mailbox */
+  NIL,				/* fetch message "fast" attributes */
+  NIL,				/* fetch message flags */
+  NIL,				/* fetch overview */
+  NIL,				/* fetch message envelopes */
+  mix_header,			/* fetch message header only */
+  mix_text,			/* fetch message body only */
+  NIL,				/* fetch partial message test */
+  NIL,				/* unique identifier */
+  NIL,				/* message number */
+  mix_flag,			/* modify flags */
+  NIL,				/* per-message modify flags */
+  NIL,				/* search for message based on criteria */
+  mix_sort,			/* sort messages */
+  mix_thread,			/* thread messages */
+  mix_ping,			/* ping mailbox to see if still alive */
+  mix_check,			/* check for new messages */
+  mix_expunge,			/* expunge deleted messages */
+  mix_copy,			/* copy messages to another mailbox */
+  mix_append,			/* append string message to mailbox */
+  NIL				/* garbage collect stream */
+};
+
+				/* prototype stream */
+MAILSTREAM mixproto = {&mixdriver};
+
+/* MIX mail validate mailbox
+ * Accepts: mailbox name
+ * Returns: our driver if name is valid, NIL otherwise
+ */
+
+DRIVER *mix_valid (char *name)
+{
+  char tmp[MAILTMPLEN];
+  return mix_isvalid (name,tmp) ? &mixdriver : NIL;
+}
+
+
+/* MIX mail test for valid mailbox
+ * Accepts: mailbox name
+ *	    buffer to return meta name
+ * Returns: T if valid, NIL otherwise, metadata name written in both cases
+ */
+
+long mix_isvalid (char *name,char *meta)
+{
+  char dir[MAILTMPLEN];
+  struct stat sbuf;
+				/* validate name as directory */
+  if (!(errno = ((strlen (name) > NETMAXMBX) ? ENAMETOOLONG : NIL)) &&
+      *mix_dir (dir,name) && mix_file (meta,dir,MIXMETA) &&
+      !stat (dir,&sbuf) && ((sbuf.st_mode & S_IFMT) == S_IFDIR)) {
+				/* name is directory; is it mix? */
+    if (!stat (meta,&sbuf) && ((sbuf.st_mode & S_IFMT) == S_IFREG))
+      return LONGT;
+    else errno = NIL;		/* directory but not mix */
+  }
+  return NIL;
+}
+
+/* MIX manipulate driver parameters
+ * Accepts: function code
+ *	    function-dependent value
+ * Returns: function-dependent return value
+ */
+
+void *mix_parameters (long function,void *value)
+{
+  void *ret = NIL;
+  switch ((int) function) {
+  case GET_INBOXPATH:
+    if (value) ret = mailboxfile ((char *) value,"~/INBOX");
+    break;
+  case GET_DIRFMTTEST:
+    ret = (void *) mix_dirfmttest;
+    break;
+  case GET_SCANCONTENTS:
+    ret = (void *) mix_scan_contents;
+    break;
+  case SET_ONETIMEEXPUNGEATPING:
+    if (value) ((MIXLOCAL *) ((MAILSTREAM *) value)->local)->expok = T;
+  case GET_ONETIMEEXPUNGEATPING:
+    if (value) ret = (void *)
+      (((MIXLOCAL *) ((MAILSTREAM *) value)->local)->expok ? VOIDT : NIL);
+    break;
+  }
+  return ret;
+}
+
+
+/* MIX test for directory format internal node
+ * Accepts: candidate node name
+ * Returns: T if internal name, NIL otherwise
+ */
+
+long mix_dirfmttest (char *name)
+{
+				/* belongs to MIX if starts with .mix */
+  return strncmp (name,MIXNAME,sizeof (MIXNAME) - 1) ? NIL : LONGT;
+}
+
+/* MIX mail scan mailboxes
+ * Accepts: mail stream
+ *	    reference
+ *	    pattern to search
+ *	    string to scan
+ */
+
+void mix_scan (MAILSTREAM *stream,char *ref,char *pat,char *contents)
+{
+  if (stream) dummy_scan (NIL,ref,pat,contents);
+}
+
+
+/* MIX scan mailbox for contents
+ * Accepts: mailbox name
+ *	    desired contents
+ *	    contents size
+ *	    file size (ignored)
+ * Returns: NIL if contents not found, T if found
+ */
+
+long mix_scan_contents (char *name,char *contents,unsigned long csiz,
+			unsigned long fsiz)
+{
+  long i,nfiles;
+  void *a;
+  char *s;
+  long ret = NIL;
+  size_t namelen = strlen (name);
+  struct stat sbuf;
+  struct direct **names = NIL;
+  if ((nfiles = scandir (name,&names,mix_select,mix_msgfsort)) > 0)
+    for (i = 0; i < nfiles; ++i) {
+      if (!ret) {
+	sprintf (s = (char *) fs_get (namelen + strlen (names[i]->d_name) + 2),
+		 "%s/%s",name,names[i]->d_name);
+	if (!stat (s,&sbuf) && (csiz <= sbuf.st_size))
+	  ret = dummy_scan_contents (s,contents,csiz,sbuf.st_size);
+	fs_give ((void **) &s);
+      }
+      fs_give ((void **) &names[i]);
+    }
+				/* free directory list */
+  if (a = (void *) names) fs_give ((void **) &a);
+  return ret;
+}
+
+/* MIX list mailboxes
+ * Accepts: mail stream
+ *	    reference
+ *	    pattern to search
+ */
+
+void mix_list (MAILSTREAM *stream,char *ref,char *pat)
+{
+  if (stream) dummy_list (NIL,ref,pat);
+}
+
+
+/* MIX list subscribed mailboxes
+ * Accepts: mail stream
+ *	    reference
+ *	    pattern to search
+ */
+
+void mix_lsub (MAILSTREAM *stream,char *ref,char *pat)
+{
+  if (stream) dummy_lsub (NIL,ref,pat);
+}
+
+/* MIX mail subscribe to mailbox
+ * Accepts: mail stream
+ *	    mailbox to add to subscription list
+ * Returns: T on success, NIL on failure
+ */
+
+long mix_subscribe (MAILSTREAM *stream,char *mailbox)
+{
+  return sm_subscribe (mailbox);
+}
+
+
+/* MIX mail unsubscribe to mailbox
+ * Accepts: mail stream
+ *	    mailbox to delete from subscription list
+ * Returns: T on success, NIL on failure
+ */
+
+long mix_unsubscribe (MAILSTREAM *stream,char *mailbox)
+{
+  return sm_unsubscribe (mailbox);
+}
+
+/* MIX mail create mailbox
+ * Accepts: mail stream
+ *	    mailbox name to create
+ * Returns: T on success, NIL on failure
+ */
+
+long mix_create (MAILSTREAM *stream,char *mailbox)
+{
+  DRIVER *test;
+  FILE *f;
+  int c,i;
+  char *t,tmp[MAILTMPLEN],file[MAILTMPLEN];
+  char *s = strrchr (mailbox,'/');
+  unsigned long now = time (NIL);
+  long ret = NIL;
+				/* always create \NoSelect if trailing /  */
+  if (s && !s[1]) return dummy_create (stream,mailbox);
+				/* validate name */
+  if (mix_dirfmttest (s ? s + 1 : mailbox))
+    sprintf(tmp,"Can't create mailbox %.80s: invalid MIX-format name",mailbox);
+				/* must not already exist */
+  else if ((test = mail_valid (NIL,mailbox,NIL)) &&
+	   strcmp (test->name,"dummy"))
+    sprintf (tmp,"Can't create mailbox %.80s: mailbox already exists",mailbox);
+				/* create directory and metadata */
+  else if (!dummy_create_path (stream,
+			       mix_file (file,mix_dir (tmp,mailbox),MIXMETA),
+			       get_dir_protection (mailbox)))
+    sprintf (tmp,"Can't create mailbox %.80s: %.80s",mailbox,strerror (errno));
+  else if (!(f = fopen (file,"w")))
+    sprintf (tmp,"Can't re-open metadata %.80s: %.80s",mailbox,
+	     strerror (errno));
+  else {			/* success, write initial metadata */
+    fprintf (f,SEQFMT,now);
+    fprintf (f,MTAFMT,now,0,now);
+    for (i = 0, c = 'K'; (i < NUSERFLAGS) &&
+	   (t = (stream && stream->user_flags[i]) ? stream->user_flags[i] :
+	    default_user_flag (i)) && *t; ++i) {
+      putc (c,f);		/* write another keyword */
+      fputs (t,f);
+      c = ' ';			/* delimiter is now space */
+    }
+    fclose (f);
+    set_mbx_protections (mailbox,file);
+				/* point to suffix */
+    s = file + strlen (file) - (sizeof (MIXMETA) - 1);
+    strcpy (s,MIXINDEX);	/* create index */
+    if (!dummy_create_path (stream,file,get_dir_protection (mailbox)))
+      sprintf (tmp,"Can't create mix mailbox index: %.80s",strerror (errno));
+    else {
+      set_mbx_protections (mailbox,file);
+      strcpy (s,MIXSTATUS);	/* create status */
+      if (!dummy_create_path (stream,file,get_dir_protection (mailbox)))
+	sprintf (tmp,"Can't create mix mailbox status: %.80s",
+		 strerror (errno));
+      else {
+	set_mbx_protections (mailbox,file);
+	sprintf (s,"%08lx",now);/* message file */
+	if (!dummy_create_path (stream,file,get_dir_protection (mailbox)))
+	  sprintf (tmp,"Can't create mix mailbox data: %.80s",
+		   strerror (errno));
+	else {
+	  set_mbx_protections (mailbox,file);
+	  ret = LONGT;	/* declare success at this point */
+	}
+      }
+    }
+  }
+  if (!ret) MM_LOG (tmp,ERROR);	/* some error */
+  return ret;
+}
+
+/* MIX mail delete mailbox
+ *	    mailbox name to delete
+ * Returns: T on success, NIL on failure
+ */
+
+long mix_delete (MAILSTREAM *stream,char *mailbox)
+{
+  DIR *dirp;
+  struct direct *d;
+  int fd = -1;
+  char *s,tmp[MAILTMPLEN];
+  if (!mix_isvalid (mailbox,tmp))
+    sprintf (tmp,"Can't delete mailbox %.80s: no such mailbox",mailbox);
+  else if (((fd = open (tmp,O_RDWR,NIL)) < 0) || flock (fd,LOCK_EX|LOCK_NB))
+    sprintf (tmp,"Can't lock mailbox for delete: %.80s",mailbox);
+				/* delete metadata */
+  else if (unlink (tmp)) sprintf (tmp,"Can't delete mailbox %.80s index: %80s",
+				  mailbox,strerror (errno));
+  else {
+    close (fd);			/* close descriptor on deleted metadata */
+				/* get directory name */
+    *(s = strrchr (tmp,'/')) = '\0';
+    if (dirp = opendir (tmp)) {	/* open directory */
+      *s++ = '/';		/* restore delimiter */
+				/* massacre messages */
+      while (d = readdir (dirp)) if (mix_dirfmttest (d->d_name)) {
+	strcpy (s,d->d_name);	/* make path */
+	unlink (tmp);		/* sayonara */
+      }
+      closedir (dirp);		/* flush directory */
+      *(s = strrchr (tmp,'/')) = '\0';
+      if (rmdir (tmp)) {	/* try to remove the directory */
+	sprintf (tmp,"Can't delete name %.80s: %.80s",
+		 mailbox,strerror (errno));
+	MM_LOG (tmp,WARN);
+      }
+    }
+    return T;			/* always success */
+  }
+  if (fd >= 0) close (fd);	/* close any descriptor on metadata */
+  MM_LOG (tmp,ERROR);		/* something failed */
+  return NIL;
+}
+
+/* MIX mail rename mailbox
+ * Accepts: MIX mail stream
+ *	    old mailbox name
+ *	    new mailbox name
+ * Returns: T on success, NIL on failure
+ */
+
+long mix_rename (MAILSTREAM *stream,char *old,char *newname)
+{
+  char c,*s,tmp[MAILTMPLEN],tmp1[MAILTMPLEN];
+  struct stat sbuf;
+  int fd = -1;
+  if (!mix_isvalid (old,tmp))
+    sprintf (tmp,"Can't rename mailbox %.80s: no such mailbox",old);
+  else if (((fd = open (tmp,O_RDWR,NIL)) < 0) || flock (fd,LOCK_EX|LOCK_NB))
+    sprintf (tmp,"Can't lock mailbox for rename: %.80s",old);
+  else if (mix_dirfmttest ((s = strrchr (newname,'/')) ? s + 1 : newname))
+    sprintf (tmp,"Can't rename to mailbox %.80s: invalid MIX-format name",
+	     newname);
+				/* new mailbox name must not be valid */
+  else if (mix_isvalid (newname,tmp))
+    sprintf (tmp,"Can't rename to mailbox %.80s: destination already exists",
+	     newname);
+  else {
+    mix_dir (tmp,old);		/* build old directory name */
+    mix_dir (tmp1,newname);	/* and new directory name */
+				/* easy if not INBOX */
+    if (compare_cstring (old,"INBOX")) {
+				/* found superior to destination name? */
+      if (s = strrchr (tmp1,'/')) {
+	c = *++s;		/* remember first character of inferior */
+	*s = '\0';		/* tie off to get just superior */
+				/* name doesn't exist, create it */
+	if ((stat (tmp1,&sbuf) || ((sbuf.st_mode & S_IFMT) != S_IFDIR)) &&
+	    !dummy_create_path (stream,tmp1,get_dir_protection (newname)))
+	  return NIL;
+	*s = c;			/* restore full name */
+      }
+      if (!rename (tmp,tmp1)) {
+	close (fd);		/* close descriptor on metadata */
+	return LONGT;
+      }
+    }
+
+				/* RFC 3501 requires this */
+    else if (dummy_create_path (stream,strcat (tmp1,"/"),
+				get_dir_protection (newname))) {
+      void *a;
+      int i,n,lasterror;
+      char *src,*dst;
+      struct direct **names = NIL;
+      size_t srcl = strlen (tmp);
+      size_t dstl = strlen (tmp1);
+				/* rename each mix file to new directory */
+      for (i = lasterror = 0,n = scandir (tmp,&names,mix_rselect,alphasort);
+	   i < n; ++i) {
+	size_t len = strlen (names[i]->d_name);
+	sprintf (src = (char *) fs_get (srcl + len + 2),"%s/%s",
+		 tmp,names[i]->d_name);
+	sprintf (dst = (char *) fs_get (dstl + len + 1),"%s%s",
+		 tmp1,names[i]->d_name);
+	if (rename (src,dst)) lasterror = errno;
+	fs_give ((void **) &src);
+	fs_give ((void **) &dst);
+	fs_give ((void **) &names[i]);
+      }
+				/* free directory list */
+      if (a = (void *) names) fs_give ((void **) &a);
+      if (lasterror) errno = lasterror;
+      else {
+	close (fd);		/* close descriptor on metadata */
+	return mix_create (NIL,"INBOX");
+      }
+    }
+    sprintf (tmp,"Can't rename mailbox %.80s to %.80s: %.80s",
+	     old,newname,strerror (errno));
+  }
+  if (fd >= 0) close (fd);	/* close any descriptor on metadata */
+  MM_LOG (tmp,ERROR);		/* something failed */
+  return NIL;
+}
+
+
+/* MIX test for mix name
+ * Accepts: candidate directory name
+ * Returns: T if mix file name, NIL otherwise
+ */
+
+int mix_rselect (struct direct *name)
+{
+  return mix_dirfmttest (name->d_name);
+}
+
+/* MIX mail open
+ * Accepts: stream to open
+ * Returns: stream on success, NIL on failure
+ */
+
+MAILSTREAM *mix_open (MAILSTREAM *stream)
+{
+  short silent;
+				/* return prototype for OP_PROTOTYPE call */
+  if (!stream) return user_flags (&mixproto);
+  if (stream->local) fatal ("mix recycle stream");
+  stream->local = memset (fs_get (sizeof (MIXLOCAL)),0,sizeof (MIXLOCAL));
+				/* note if an INBOX or not */
+  stream->inbox = !compare_cstring (stream->mailbox,"INBOX");
+				/* make temporary buffer */
+  LOCAL->buf = (char *) fs_get (CHUNKSIZE);
+  LOCAL->buflen = CHUNKSIZE - 1;
+				/* set stream->mailbox to be directory name */
+  mix_dir (LOCAL->buf,stream->mailbox);
+  fs_give ((void **) &stream->mailbox);
+  stream->mailbox = cpystr (LOCAL->buf);
+  LOCAL->msgfd = -1;		/* currently no file open */
+  if (!(((!stream->rdonly &&	/* open metadata file */
+	  ((LOCAL->mfd = open (mix_file (LOCAL->buf,stream->mailbox,MIXMETA),
+			       O_RDWR,NIL)) >= 0)) ||
+	 ((stream->rdonly = T) &&
+	  ((LOCAL->mfd = open (mix_file (LOCAL->buf,stream->mailbox,MIXMETA),
+			       O_RDONLY,NIL)) >= 0))) &&
+	!flock (LOCAL->mfd,LOCK_SH))) {
+    MM_LOG ("Error opening mix metadata file",ERROR);
+    mix_abort (stream);
+    stream = NIL;		/* open fails */
+  }
+  else {			/* metadata open, complete open */
+    LOCAL->index = cpystr (mix_file (LOCAL->buf,stream->mailbox,MIXINDEX));
+    LOCAL->status = cpystr (mix_file (LOCAL->buf,stream->mailbox,MIXSTATUS));
+    LOCAL->sortcache = cpystr (mix_file (LOCAL->buf,stream->mailbox,
+					 MIXSORTCACHE));
+    stream->sequence++;		/* bump sequence number */
+				/* parse mailbox */
+    stream->nmsgs = stream->recent = 0;
+    if (silent = stream->silent) LOCAL->internal = T;
+    stream->silent = T;
+    if (mix_ping (stream)) {	/* do initial ping */
+				/* try burping in case we are exclusive */
+      if (!stream->rdonly) mix_expunge (stream,"",NIL);
+      if (!(stream->nmsgs || stream->silent))
+	MM_LOG ("Mailbox is empty",(long) NIL);
+      stream->silent = silent;	/* now notify upper level */
+      mail_exists (stream,stream->nmsgs);
+      stream->perm_seen = stream->perm_deleted = stream->perm_flagged =
+	stream->perm_answered = stream->perm_draft = stream->rdonly ? NIL : T;
+      stream->perm_user_flags = stream->rdonly ? NIL : 0xffffffff;
+      stream->kwd_create =	/* can we create new user flags? */
+	(stream->user_flags[NUSERFLAGS-1] || stream->rdonly) ? NIL : T;
+    }
+    else {			/* got murdelyzed in ping */
+      mix_abort (stream);
+      stream = NIL;
+    }
+  }
+  return stream;		/* return stream to caller */
+}
+
+/* MIX mail close
+ * Accepts: MAIL stream
+ *	    close options
+ */
+
+void mix_close (MAILSTREAM *stream,long options)
+{
+  if (LOCAL) {			/* only if a file is open */
+    int silent = stream->silent;
+    stream->silent = T;		/* note this stream is dying */
+				/* burp-only or expunge */
+    mix_expunge (stream,(options & CL_EXPUNGE) ? NIL : "",NIL);
+    mix_abort (stream);
+    stream->silent = silent;	/* reset silent state */
+  }
+}
+
+
+/* MIX mail abort stream
+ * Accepts: MAIL stream
+ */
+
+void mix_abort (MAILSTREAM *stream)
+{
+  if (LOCAL) {			/* only if a file is open */
+				/* close current message file if open */
+    if (LOCAL->msgfd >= 0) close (LOCAL->msgfd);
+				/* close current metadata file if open */
+    if (LOCAL->mfd >= 0) close (LOCAL->mfd);
+    if (LOCAL->index) fs_give ((void **) &LOCAL->index);
+    if (LOCAL->status) fs_give ((void **) &LOCAL->status);
+    if (LOCAL->sortcache) fs_give ((void **) &LOCAL->sortcache);
+				/* free local scratch buffer */
+    if (LOCAL->buf) fs_give ((void **) &LOCAL->buf);
+				/* nuke the local data */
+    fs_give ((void **) &stream->local);
+    stream->dtb = NIL;		/* log out the DTB */
+  }
+}
+
+/* MIX mail fetch message header
+ * Accepts: MAIL stream
+ *	    message # to fetch
+ *	    pointer to returned header text length
+ *	    option flags
+ * Returns: message header in RFC822 format
+ */
+
+char *mix_header (MAILSTREAM *stream,unsigned long msgno,unsigned long *length,
+		  long flags)
+{
+  unsigned long i,j,k;
+  int fd;
+  char *s,tmp[MAILTMPLEN];
+  MESSAGECACHE *elt;
+  if (length) *length = 0;	/* default return */
+  if (flags & FT_UID) return "";/* UID call "impossible" */
+  elt = mail_elt (stream,msgno);/* get elt */
+				/* is message in current message file? */
+  if ((LOCAL->msgfd < 0) || (elt->private.spare.data != LOCAL->curmsg)) {
+    if (LOCAL->msgfd >= 0) close (LOCAL->msgfd);
+    if ((LOCAL->msgfd = open (mix_file_data (LOCAL->buf,stream->mailbox,
+					     elt->private.spare.data),
+					     O_RDONLY,NIL)) < 0) return "";
+				/* got file */
+    LOCAL->curmsg = elt->private.spare.data;
+  }    
+  lseek (LOCAL->msgfd,elt->private.special.offset,L_SET);
+				/* size of special data and header */
+  j = elt->private.msg.header.offset + elt->private.msg.header.text.size;
+  if (j > LOCAL->buflen) {	/* is buffer big enough? */
+				/* no, make one that is */
+    fs_give ((void **) &LOCAL->buf);
+    LOCAL->buf = (char *) fs_get ((LOCAL->buflen = j) + 1);
+  }
+  /* Maybe someday validate internaldate too */
+				/* slurp special data + header, validate */
+  if ((read (LOCAL->msgfd,LOCAL->buf,j) == j) &&
+      !strncmp (LOCAL->buf,MSGTOK,MSGTSZ) &&
+      (elt->private.uid == strtoul ((char *) LOCAL->buf + MSGTSZ,&s,16)) &&
+      (*s++ == ':') && (s = strchr (s,':')) &&
+      (k = strtoul (s+1,&s,16)) && (*s++ == ':') &&
+      (s < (char *) (LOCAL->buf + elt->private.msg.header.offset))) {
+				/* won, set offset and size of message */
+    i = elt->private.msg.header.offset;
+    *length = elt->private.msg.header.text.size;
+    if (k != elt->rfc822_size) {
+      sprintf (tmp,"Inconsistency in mix message size, uid=%lx (%lu != %lu)",
+	       elt->private.uid,elt->rfc822_size,k);
+      MM_LOG (tmp,WARN);
+    }
+  }
+  else {			/* document the problem */
+    LOCAL->buf[100] = '\0';	/* tie off buffer at no more than 100 octets */
+				/* or at newline, whichever is first */
+    if (s = strpbrk (LOCAL->buf,"\015\012")) *s = '\0';
+    sprintf (tmp,"Error reading mix message header, uid=%lx, s=%.0lx, h=%s",
+	     elt->private.uid,elt->rfc822_size,LOCAL->buf);
+    MM_LOG (tmp,ERROR);
+    *length = i = j = 0;	/* default to empty */
+  }
+  LOCAL->buf[j] = '\0';		/* tie off buffer at the end */
+  return (char *) LOCAL->buf + i;
+}
+
+/* MIX mail fetch message text (body only)
+ * Accepts: MAIL stream
+ *	    message # to fetch
+ *	    pointer to returned stringstruct
+ *	    option flags
+ * Returns: T on success, NIL on failure
+ */
+
+long mix_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags)
+{
+  unsigned long i;
+  FDDATA d;
+  MESSAGECACHE *elt;
+				/* UID call "impossible" */
+  if (flags & FT_UID) return NIL;
+  elt = mail_elt (stream,msgno);
+				/* is message in current message file? */
+  if ((LOCAL->msgfd < 0) || (elt->private.spare.data != LOCAL->curmsg)) {
+    if (LOCAL->msgfd >= 0) close (LOCAL->msgfd);
+    if ((LOCAL->msgfd = open (mix_file_data (LOCAL->buf,stream->mailbox,
+					     elt->private.spare.data),
+					     O_RDONLY,NIL)) < 0) return NIL;
+				/* got file */
+    LOCAL->curmsg = elt->private.spare.data;
+  }    
+				/* doing non-peek fetch? */
+  if (!(flags & FT_PEEK) && !elt->seen) {
+    FILE *idxf;			/* yes, process metadata/index/status */
+    FILE *statf = mix_parse (stream,&idxf,NIL,LONGT);
+    elt->seen = T;		/* mark as seen */
+    MM_FLAGS (stream,elt->msgno);
+				/* update status file if possible */
+    if (statf && !stream->rdonly) {
+      elt->private.mod = LOCAL->statusseq = mix_modseq (LOCAL->statusseq);
+      mix_status_update (stream,statf,NIL);
+    }
+    if (idxf) fclose (idxf);	/* release index and status file */
+    if (statf) fclose (statf);
+  } 
+  d.fd = LOCAL->msgfd;		/* set up file descriptor */
+				/* offset of message text */
+  d.pos = elt->private.special.offset + elt->private.msg.header.offset +
+    elt->private.msg.header.text.size;
+  d.chunk = LOCAL->buf;		/* initial buffer chunk */
+  d.chunksize = CHUNKSIZE;	/* chunk size */
+  INIT (bs,fd_string,&d,elt->rfc822_size - elt->private.msg.header.text.size);
+  return T;
+}
+
+/* MIX mail modify flags
+ * Accepts: MAIL stream
+ *	    sequence
+ *	    flag(s)
+ *	    option flags
+ */
+
+void mix_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags)
+{
+  MESSAGECACHE *elt;
+  unsigned long i,uf,ffkey;
+  long f;
+  short nf;
+  FILE *idxf;
+  FILE *statf = mix_parse (stream,&idxf,NIL,LONGT);
+  unsigned long seq = mix_modseq (LOCAL->statusseq);
+				/* find first free key */
+  for (ffkey = 0; (ffkey < NUSERFLAGS) && stream->user_flags[ffkey]; ++ffkey);
+				/* parse sequence and flags */
+  if (((flags & ST_UID) ? mail_uid_sequence (stream,sequence) :
+       mail_sequence (stream,sequence)) &&
+      ((f = mail_parse_flags (stream,flag,&uf)) || uf)) {
+				/* alter flags */
+    for (i = 1,nf = (flags & ST_SET) ? T : NIL; i <= stream->nmsgs; i++)
+      if ((elt = mail_elt (stream,i))->sequence) {
+	struct {		/* old flags */
+	  unsigned int seen : 1;
+	  unsigned int deleted : 1;
+	  unsigned int flagged : 1;
+	  unsigned int answered : 1;
+	  unsigned int draft : 1;
+	  unsigned long user_flags;
+	} old;
+	old.seen = elt->seen; old.deleted = elt->deleted;
+	old.flagged = elt->flagged; old.answered = elt->answered;
+	old.draft = elt->draft; old.user_flags = elt->user_flags;
+	if (f&fSEEN) elt->seen = nf;
+	if (f&fDELETED) elt->deleted = nf;
+	if (f&fFLAGGED) elt->flagged = nf;
+	if (f&fANSWERED) elt->answered = nf;
+	if (f&fDRAFT) elt->draft = nf;
+				/* user flags */
+	if (flags & ST_SET) elt->user_flags |= uf;
+	else elt->user_flags &= ~uf;
+	if ((old.seen != elt->seen) || (old.deleted != elt->deleted) ||
+	    (old.flagged != elt->flagged) ||
+	    (old.answered != elt->answered) || (old.draft != elt->draft) ||
+	    (old.user_flags != elt->user_flags)) {
+	  if (!stream->rdonly) elt->private.mod = LOCAL->statusseq = seq;
+	  MM_FLAGS (stream,elt->msgno);
+	}
+      }
+				/* update status file after change */
+    if (statf && (seq == LOCAL->statusseq))
+      mix_status_update (stream,statf,NIL);
+				/* update metadata if created a keyword */
+    if ((ffkey < NUSERFLAGS) && stream->user_flags[ffkey] &&
+	!mix_meta_update (stream))
+      MM_LOG ("Error updating mix metadata after keyword creation",ERROR);
+  }
+  if (statf) fclose (statf);	/* release status file if still open */
+  if (idxf) fclose (idxf);	/* release index file */
+}
+
+/* MIX mail sort messages
+ * Accepts: mail stream
+ *	    character set
+ *	    search program
+ *	    sort program
+ *	    option flags
+ * Returns: vector of sorted message sequences or NIL if error
+ */
+
+unsigned long *mix_sort (MAILSTREAM *stream,char *charset,SEARCHPGM *spg,
+			 SORTPGM *pgm,long flags)
+{
+  unsigned long *ret;
+  FILE *sortcache = mix_sortcache_open (stream);
+  ret = mail_sort_msgs (stream,charset,spg,pgm,flags);
+  mix_sortcache_update (stream,&sortcache);
+  return ret;
+}
+
+
+/* MIX mail thread messages
+ * Accepts: mail stream
+ *	    thread type
+ *	    character set
+ *	    search program
+ *	    option flags
+ * Returns: thread node tree or NIL if error
+ */
+
+THREADNODE *mix_thread (MAILSTREAM *stream,char *type,char *charset,
+			SEARCHPGM *spg,long flags)
+{
+  THREADNODE *ret;
+  FILE *sortcache = mix_sortcache_open (stream);
+  ret = mail_thread_msgs (stream,type,charset,spg,flags,mail_sort_msgs);
+  mix_sortcache_update (stream,&sortcache);
+  return ret;
+}
+
+/* MIX mail ping mailbox
+ * Accepts: MAIL stream
+ * Returns: T if stream alive, else NIL
+ */
+
+static int snarfing = 0;	/* lock against recursive snarfing */
+
+long mix_ping (MAILSTREAM *stream)
+{
+  FILE *idxf,*statf;
+  struct stat sbuf;
+  STRING msg;
+  MESSAGECACHE *elt;
+  int mfd,ifd,sfd;
+  unsigned long i,msglen;
+  char *message,date[MAILTMPLEN],flags[MAILTMPLEN];
+  MAILSTREAM *sysibx = NIL;
+  long ret = NIL;
+  long snarfok = LONGT;
+				/* time to snarf? */
+  if (stream->inbox && !stream->rdonly && !snarfing &&
+      (time (0) >= (LOCAL->lastsnarf +
+		    (time_t) mail_parameters (NIL,GET_SNARFINTERVAL,NIL)))) {
+    appenduid_t au = (appenduid_t) mail_parameters (NIL,GET_APPENDUID,NIL);
+    copyuid_t cu = (copyuid_t) mail_parameters (NIL,GET_COPYUID,NIL);
+    MM_CRITICAL (stream);	/* go critical */
+    snarfing = T;		/* don't recursively snarf */
+				/* disable APPENDUID/COPYUID callbacks */
+    mail_parameters (NIL,SET_APPENDUID,NIL);
+    mail_parameters (NIL,SET_COPYUID,NIL);
+				/* sizes match and anything in sysinbox? */
+    if (!stat (sysinbox (),&sbuf) && ((sbuf.st_mode & S_IFMT) == S_IFREG) &&
+	sbuf.st_size &&	(sysibx = mail_open (sysibx,sysinbox (),OP_SILENT)) &&
+	!sysibx->rdonly && sysibx->nmsgs) {
+				/* for each message in sysibx mailbox */
+      for (i = 1; snarfok && (i <= sysibx->nmsgs); ++i)
+	if (!(elt = mail_elt (sysibx,i))->deleted &&
+	    (message = mail_fetch_message (sysibx,i,&msglen,FT_PEEK)) &&
+	    msglen) {
+	  mail_date (date,elt);	/* make internal date string */
+				/* make flag string */
+	  flags[0] = flags[1] = '\0';
+	  if (elt->seen) strcat (flags," \\Seen");
+	  if (elt->flagged) strcat (flags," \\Flagged");
+	  if (elt->answered) strcat (flags," \\Answered");
+	  if (elt->draft) strcat (flags," \\Draft");
+	  flags[0] = '(';
+	  strcat (flags,")");
+	  INIT (&msg,mail_string,message,msglen);
+	  if (snarfok = mail_append_full (stream,"INBOX",flags,date,&msg)) {
+	    char sequence[15];
+	    sprintf (sequence,"%lu",i);
+	    mail_flag (sysibx,sequence,"\\Deleted",ST_SET);
+	  }
+	}
+
+				/* now expunge all those messages */
+      if (snarfok) mail_expunge (sysibx);
+      else {
+	sprintf (LOCAL->buf,"Can't copy new mail at message: %lu",i - 1);
+	MM_LOG (LOCAL->buf,WARN);
+      }
+    }
+    if (sysibx) mail_close (sysibx);
+				/* reenable APPENDUID/COPYUID */
+    mail_parameters (NIL,SET_APPENDUID,(void *) au);
+    mail_parameters (NIL,SET_COPYUID,(void *) cu);
+    snarfing = NIL;		/* no longer snarfing */
+    MM_NOCRITICAL (stream);	/* release critical */
+    LOCAL->lastsnarf = time (0);/* note time of last snarf */
+  }
+				/* expunging OK if global flag set */
+  if (mail_parameters (NIL,GET_EXPUNGEATPING,NIL)) LOCAL->expok = T;
+				/* process metadata/index/status */
+  if (statf = mix_parse (stream,&idxf,LONGT,
+			 (LOCAL->internal ? NIL : LONGT))) {
+    fclose (statf);		/* just close the status file */
+    ret = LONGT;		/* declare success */
+  }
+  if (idxf) fclose (idxf);	/* release index file */
+  LOCAL->expok = NIL;		/* expunge no longer OK */
+  if (!ret) mix_abort (stream);	/* murdelyze stream if ping fails */
+  return ret;
+}
+
+
+/* MIX mail checkpoint mailbox (burp only)
+ * Accepts: MAIL stream
+ */
+
+void mix_check (MAILSTREAM *stream)
+{
+  if (stream->rdonly)		/* won't do on readonly files! */
+    MM_LOG ("Checkpoint ignored on readonly mailbox",NIL);
+				/* do burp-only expunge action */
+  if (mix_expunge (stream,"",NIL)) MM_LOG ("Check completed",(long) NIL);
+}
+
+/* MIX mail expunge mailbox
+ * Accepts: MAIL stream
+ *	    sequence to expunge if non-NIL, empty string for burp only
+ *	    expunge options
+ * Returns: T on success, NIL if failure
+ */
+
+long mix_expunge (MAILSTREAM *stream,char *sequence,long options)
+{
+  FILE *idxf = NIL;
+  FILE *statf = NIL;
+  MESSAGECACHE *elt;
+  int ifd,sfd;
+  long ret;
+  unsigned long i;
+  unsigned long nexp = 0;
+  unsigned long reclaimed = 0;
+  int burponly = (sequence && !*sequence);
+  LOCAL->expok = T;		/* expunge during ping is OK */
+  if (!(ret = burponly || !sequence ||
+	((options & EX_UID) ?
+	 mail_uid_sequence (stream,sequence) :
+	 mail_sequence (stream,sequence))) || stream->rdonly);
+				/* read index and open status exclusive */
+  else if (statf = mix_parse (stream,&idxf,LONGT,
+			      LOCAL->internal ? NIL : LONGT)) {
+				/* expunge unless just burping */
+    if (!burponly) for (i = 1; i <= stream->nmsgs;) {
+      elt = mail_elt (stream,i);/* need to expunge this message? */
+      if (sequence ? elt->sequence : elt->deleted) {
+	++nexp;			/* yes, make it so */
+	mail_expunged (stream,i);
+      }
+      else ++i;		       /* otherwise advance to next message */
+    }
+
+				/* burp if can get exclusive access */
+    if (!flock (LOCAL->mfd,LOCK_EX|LOCK_NB)) {
+      void *a;
+      struct direct **names = NIL;
+      long nfiles = scandir (stream->mailbox,&names,mix_select,mix_msgfsort);
+      if (nfiles > 0) {		/* if have message files */
+	MIXBURP *burp,*cur;
+				/* initialize burp list */
+	for (i = 0, burp = cur = NIL; i < nfiles; ++i) {
+	  MIXBURP *nxt = (MIXBURP *) memset (fs_get (sizeof (MIXBURP)),0,
+					     sizeof (MIXBURP));
+				/* another file found */
+	  if (cur) cur = cur->next = nxt;
+	  else cur = burp = nxt;
+	  cur->name = names[i]->d_name;
+	  cur->fileno = strtoul (cur->name + sizeof (MIXNAME) - 1,NIL,16);
+	  cur->tail = &cur->set;
+	  fs_give ((void **) &names[i]);
+	}
+				/* now load ranges */
+	for (i = 1, cur = burp; ret && (i <= stream->nmsgs); i++) {
+				/* is this message in current set? */
+	  elt = mail_elt (stream,i);
+	  if (cur && (elt->private.spare.data != cur->fileno)) {
+				/* restart if necessary */
+	    if (elt->private.spare.data < cur->fileno) cur = burp;
+				/* hunt for appropriate mailbox */
+	    while (cur && (elt->private.spare.data > cur->fileno))
+	      cur = cur->next;
+				/* ought to have found it now... */
+	    if (cur && (elt->private.spare.data != cur->fileno)) cur = NIL;
+	  }
+				/* if found, add to set */
+	  if (cur) ret = mix_addset (&cur->tail,elt->private.special.offset,
+				     elt->private.msg.header.offset +
+				     elt->rfc822_size);
+	  else {		/* uh-oh */
+	    sprintf (LOCAL->buf,"Can't locate mix message file %.08lx",
+		     elt->private.spare.data);
+	    MM_LOG (LOCAL->buf,ERROR);
+	    ret = NIL;
+	  }
+	}
+	if (ret) 		/* if no errors, burp all files */
+	  for (cur = burp; ret && cur; cur = cur->next) {
+				/* if non-empty, burp it */
+	    if (cur->set.last) ret = mix_burp (stream,cur,&reclaimed);
+				/* empty, delete it unless new msg file */
+	    else if (mix_file_data (LOCAL->buf,stream->mailbox,cur->fileno) &&
+		     ((cur->fileno == LOCAL->newmsg) ?
+		      truncate (LOCAL->buf,0) : unlink (LOCAL->buf))) {
+	      sprintf (LOCAL->buf,
+		       "Can't delete empty message file %.80s: %.80s",
+		       cur->name,strerror (errno));
+	      MM_LOG (LOCAL->buf,WARN);
+	    }
+	  }
+      }
+      else MM_LOG ("No mix message files found during expunge",WARN);
+				/* free directory list */
+      if (a = (void *) names) fs_give ((void **) &a);
+    }
+
+				/* either way, re-acquire shared lock */
+    if (flock (LOCAL->mfd,LOCK_SH|LOCK_NB))
+      fatal ("Unable to re-acquire metadata shared lock!");
+    /* Do this step even if ret is NIL (meaning some burp problem)! */
+    if (nexp || reclaimed) {	/* rewrite index and status if changed */
+      LOCAL->indexseq = mix_modseq (LOCAL->indexseq);
+      if (mix_index_update (stream,idxf,NIL)) {
+	LOCAL->statusseq = mix_modseq (LOCAL->statusseq);
+				/* set failure if update fails */
+	ret = mix_status_update (stream,statf,NIL);
+      }
+    }
+  }
+  if (statf) fclose (statf);	/* close status if still open */
+  if (idxf) fclose (idxf);	/* close index if still open */
+  LOCAL->expok = NIL;		/* cancel expok */
+  if (ret) {			/* only if success */
+    char *s = NIL;
+    if (nexp) sprintf (s = LOCAL->buf,"Expunged %lu messages",nexp);
+    else if (reclaimed)
+      sprintf (s=LOCAL->buf,"Reclaimed %lu bytes of expunged space",reclaimed);
+    else if (!burponly)
+      s = stream->rdonly ? "Expunge ignored on readonly mailbox" :
+	   "No messages deleted, so no update needed";
+    if (s) MM_LOG (s,(long) NIL);
+  }
+  return ret;
+}
+
+/* MIX test for message file name
+ * Accepts: candidate directory name
+ * Returns: T if message file name, NIL otherwise
+ *
+ * ".mix" with no suffix was used by experimental versions
+ */
+
+int mix_select (struct direct *name)
+{
+  char c,*s;
+				/* make sure name has prefix */
+  if (mix_dirfmttest (name->d_name)) {
+    for (c = *(s = name->d_name + sizeof (MIXNAME) - 1); c && isxdigit (c);
+	 c = *s++);
+    if (!c) return T;		/* all-hex or no suffix */
+  }
+  return NIL;			/* not suffix or non-hex */
+}
+
+
+/* MIX msg file name comparision
+ * Accepts: first candidate directory entry
+ *	    second candidate directory entry
+ * Returns: -1 if d1 < d2, 0 if d1 == d2, 1 d1 > d2
+ */
+
+int mix_msgfsort (const void *d1,const void *d2)
+{
+  char *n1 = (*(struct direct **) d1)->d_name + sizeof (MIXNAME) - 1;
+  char *n2 = (*(struct direct **) d2)->d_name + sizeof (MIXNAME) - 1;
+  return compare_ulong (*n1 ? strtoul (n1,NIL,16) : 0,
+			*n2 ? strtoul (n2,NIL,16) : 0);
+}
+
+
+/* MIX add a range to a set
+ * Accepts: pointer to set to add
+ *	    start of set
+ *	    size of set
+ * Returns: T if success, set updated, NIL otherwise
+ */
+
+long mix_addset (SEARCHSET **set,unsigned long start,unsigned long size)
+{
+  SEARCHSET *s = *set;
+  if (start < s->last) {	/* sanity check */
+    char tmp[MAILTMPLEN];
+    sprintf (tmp,"Backwards-running mix index %lu < %lu",start,s->last);
+    MM_LOG (tmp,ERROR);
+    return NIL;
+  }
+				/* range initially empty? */
+  if (!s->last) s->first = start;
+  else if (start > s->last)	/* no, start new range if can't append */
+    (*set = s = s->next = mail_newsearchset ())->first = start;
+  s->last = start + size;	/* end of current range */
+  return LONGT;
+}
+
+/* MIX burp message file
+ * Accepts: MAIL stream
+ *	    current burp block for this message
+ * Returns: T if successful, NIL if failed
+ */
+
+static char *staterr = "Error in stat of mix message file %.80s: %.80s";
+static char *truncerr = "Error truncating mix message file %.80s: %.80s";
+
+long mix_burp (MAILSTREAM *stream,MIXBURP *burp,unsigned long *reclaimed)
+{
+  MESSAGECACHE *elt;
+  SEARCHSET *set;
+  struct stat sbuf;
+  off_t rpos,wpos;
+  size_t size,wsize,wpending,written;
+  int fd;
+  FILE *f;
+  void *s;
+  unsigned long i;
+  long ret = NIL;
+				/* build file name */
+  mix_file_data (LOCAL->buf,stream->mailbox,burp->fileno);
+				/* need to burp at start or multiple ranges? */
+  if (!burp->set.first && !burp->set.next) {
+				/* easy case, single range at start of file */
+    if (stat (LOCAL->buf,&sbuf)) {
+      sprintf (LOCAL->buf,staterr,burp->name,strerror (errno));
+      MM_LOG (LOCAL->buf,ERROR);
+    }
+				/* is this range sane? */
+    else if (mix_burp_check (&burp->set,sbuf.st_size,LOCAL->buf)) {
+				/* if matches range then no burp needed! */
+      if (burp->set.last == sbuf.st_size) ret = LONGT;
+				/* just need to remove cruft at end */
+      else if (ret = !truncate (LOCAL->buf,burp->set.last))
+	*reclaimed += sbuf.st_size - burp->set.last;
+      else {
+	sprintf (LOCAL->buf,truncerr,burp->name,strerror (errno));
+	MM_LOG (LOCAL->buf,ERROR);
+      }
+    }
+  }
+				/* have to do more work, get the file */
+  else if (((fd = open (LOCAL->buf,O_RDWR,NIL)) < 0) ||
+	   !(f = fdopen (fd,"r+b"))) {
+    sprintf (LOCAL->buf,"Error opening mix message file %.80s: %.80s",
+	     burp->name,strerror (errno));
+    MM_LOG (LOCAL->buf,ERROR);
+    if (fd >= 0) close (fd);	/* in case fdopen() failure */
+  }
+  else if (fstat (fd,&sbuf)) {	/* get file size */
+    sprintf (LOCAL->buf,staterr,burp->name,strerror (errno));
+    MM_LOG (LOCAL->buf,ERROR);
+    fclose (f);
+  }
+
+				/* only if sane */
+  else if (mix_burp_check (&burp->set,sbuf.st_size,LOCAL->buf)) {
+				/* make sure each range starts with token */
+    for (set = &burp->set; set; set = set->next)
+      if (fseek (f,set->first,SEEK_SET) ||
+	  (fread (LOCAL->buf,1,MSGTSZ,f) != MSGTSZ) ||
+	  strncmp (LOCAL->buf,MSGTOK,MSGTSZ)) {
+	sprintf (LOCAL->buf,"Bad message token in mix message file at %lu",
+		 set->first);
+	MM_LOG (LOCAL->buf,ERROR);
+	fclose (f);
+	return NIL;		/* burp fails for this file */
+      }
+				/* burp out each old message */
+    for (set = &burp->set, wpos = 0; set; set = set->next) {
+				/* move down this range */
+      for (rpos = set->first, size = set->last - set->first;
+	   size; size -= wsize) {
+	if (rpos != wpos) {	/* data to skip at start? */
+				/* no, slide this buffer down */
+	  wsize = min (size,LOCAL->buflen);
+				/* failure is not an option here */
+	  while (fseek (f,rpos,SEEK_SET) ||
+		 (fread (LOCAL->buf,1,wsize,f) != wsize)) {
+	    MM_NOTIFY (stream,strerror (errno),WARN);
+	    MM_DISKERROR (stream,errno,T);
+	  }
+				/* nor here */
+	  while (fseek (f,wpos,SEEK_SET)) {
+	    MM_NOTIFY (stream,strerror (errno),WARN);
+	    MM_DISKERROR (stream,errno,T);
+	  }
+				/* and especially not here */
+	  for (s = LOCAL->buf, wpending = wsize; wpending; wpending -= written)
+	    if (!(written = fwrite (LOCAL->buf,1,wpending,f))) {
+	      MM_NOTIFY (stream,strerror (errno),WARN);
+	      MM_DISKERROR (stream,errno,T);
+	    }
+	}
+	else wsize = size;	/* nothing to skip, say we wrote it all */
+	rpos += wsize; wpos += wsize;
+      }
+    }
+
+    while (fflush (f)) {	/* failure also not an option here... */
+      MM_NOTIFY (stream,strerror (errno),WARN);
+      MM_DISKERROR (stream,errno,T);
+    }
+    if (ftruncate (fd,wpos)) {	/* flush cruft at end of file */
+      sprintf (LOCAL->buf,truncerr,burp->name,strerror (errno));
+      MM_LOG (LOCAL->buf,WARN);
+    }
+    else *reclaimed += rpos - wpos;
+    ret = !fclose (f);		/* close file */
+				/* slide down message positions in index */
+    for (i = 1,rpos = 0; i <= stream->nmsgs; ++i)
+      if ((elt = mail_elt (stream,i))->private.spare.data == burp->fileno) {
+	elt->private.special.offset = rpos;
+	rpos += elt->private.msg.header.offset + elt->rfc822_size;
+      }
+				/* debugging */
+    if (rpos != wpos) fatal ("burp size consistency check!");
+  }
+  return ret;
+}
+
+
+/* MIX burp sanity check to make sure not burping off end of file
+ * Accepts: burp set
+ *	    file size
+ *	    file name
+ * Returns: T if sane, NIL if insane
+ */
+
+long mix_burp_check (SEARCHSET *set,size_t size,char *file)
+{
+  do if (set->last > size) {	/* sanity check */
+    char tmp[MAILTMPLEN];
+    sprintf (tmp,"Unexpected short mix message file %.80s %lu < %lu",
+	     file,size,set->last);
+    MM_LOG (tmp,ERROR);
+    return NIL;			/* don't burp this file at all */
+  } while (set = set->next);
+  return LONGT;
+}
+
+/* MIX mail copy message(s)
+ * Accepts: MAIL stream
+ *	    sequence
+ *	    destination mailbox
+ *	    copy options
+ * Returns: T if copy successful, else NIL
+ */
+
+long mix_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options)
+{
+  FDDATA d;
+  STRING st;
+  char tmp[2*MAILTMPLEN];
+  long ret = mix_isvalid (mailbox,LOCAL->buf);
+  mailproxycopy_t pc =
+    (mailproxycopy_t) mail_parameters (stream,GET_MAILPROXYCOPY,NIL);
+  MAILSTREAM *astream = NIL;
+  FILE *idxf = NIL;
+  FILE *msgf = NIL;
+  FILE *statf = NIL;
+  if (!ret) switch (errno) {	/* make sure valid mailbox */
+  case NIL:			/* no error in stat() */
+    if (pc) return (*pc) (stream,sequence,mailbox,options);
+    sprintf (tmp,"Not a MIX-format mailbox: %.80s",mailbox);
+    MM_LOG (tmp,ERROR);
+    break;
+  default:			/* some stat() error */
+    MM_NOTIFY (stream,"[TRYCREATE] Must create mailbox before copy",NIL);
+    break;
+  }
+				/* get sequence to copy */
+  else if (!(ret = ((options & CP_UID) ? mail_uid_sequence (stream,sequence) :
+		    mail_sequence (stream,sequence))));
+				/* acquire stream to append */
+  else if (ret = ((astream = mail_open (NIL,mailbox,OP_SILENT)) &&
+		  !astream->rdonly &&
+		  (((MIXLOCAL *) astream->local)->expok = T) &&
+		  (statf = mix_parse (astream,&idxf,LONGT,NIL))) ?
+	   LONGT : NIL) {
+    int fd;
+    unsigned long i;
+    MESSAGECACHE *elt;
+    unsigned long newsize,hdrsize,size;
+    MIXLOCAL *local = (MIXLOCAL *) astream->local;
+    unsigned long seq = mix_modseq (local->metaseq);
+				/* make sure new modseq fits */
+    if (local->indexseq > seq) seq = local->indexseq + 1;
+    if (local->statusseq > seq) seq = local->statusseq + 1;
+				/* calculate size of per-message header */
+    sprintf (local->buf,MSRFMT,MSGTOK,0,0,0,0,0,0,0,'+',0,0,0);
+    hdrsize = strlen (local->buf);
+
+    MM_CRITICAL (stream);	/* go critical */
+    astream->silent = T;	/* no events here */
+				/* calculate size that will be added */
+    for (i = 1, newsize = 0; i <= stream->nmsgs; ++i)
+      if ((elt = mail_elt (stream,i))->sequence)
+	newsize += hdrsize + elt->rfc822_size;
+				/* open data file */
+    if (msgf = mix_data_open (astream,&fd,&size,newsize)) {
+      char *t;
+      unsigned long j,uid,uidv;
+      copyuid_t cu = (copyuid_t) mail_parameters (NIL,GET_COPYUID,NIL);
+      SEARCHSET *source = cu ? mail_newsearchset () : NIL;
+      SEARCHSET *dest = cu ? mail_newsearchset () : NIL;
+      for (i = 1,uid = uidv = 0; ret && (i <= stream->nmsgs); ++i) 
+	if (((elt = mail_elt (stream,i))->sequence) && elt->rfc822_size) {
+				/* is message in current message file? */
+	  if ((LOCAL->msgfd < 0) ||
+	      (elt->private.spare.data != LOCAL->curmsg)) {
+	    if (LOCAL->msgfd >= 0) close (LOCAL->msgfd);
+	    if ((LOCAL->msgfd = open (mix_file_data (LOCAL->buf,
+						     stream->mailbox,
+						     elt->private.spare.data),
+				      O_RDONLY,NIL)) >= 0)
+	      LOCAL->curmsg = elt->private.spare.data;
+	  }
+	  if (LOCAL->msgfd < 0) ret = NIL;
+	  else {		/* got file */
+	    d.fd = LOCAL->msgfd;/* set up file descriptor */
+				/* start of message */
+	    d.pos = elt->private.special.offset +
+	      elt->private.msg.header.offset;
+	    d.chunk = LOCAL->buf;
+	    d.chunksize = CHUNKSIZE;
+	    INIT (&st,fd_string,&d,elt->rfc822_size);
+				/* init flag string */
+	    tmp[0] = tmp[1] = '\0';
+	    if (j = elt->user_flags) do
+	      if ((t = stream->user_flags[find_rightmost_bit (&j)]) && *t)
+		strcat (strcat (tmp," "),t);
+	    while (j);
+	    if (elt->seen) strcat (tmp," \\Seen");
+	    if (elt->deleted) strcat (tmp," \\Deleted");
+	    if (elt->flagged) strcat (tmp," \\Flagged");
+	    if (elt->answered) strcat (tmp," \\Answered");
+	    if (elt->draft) strcat (tmp," \\Draft");
+	    tmp[0] = '(';	/* wrap list */
+	    strcat (tmp,")");
+				/* if append OK, add to source set */
+	    if ((ret = mix_append_msg (astream,msgf,tmp,elt,&st,dest,
+				       seq)) &&	source)
+	      mail_append_set (source,mail_uid (stream,i));
+	  }
+	}
+
+				/* finish write if success */
+      if (ret && (ret = !fflush (msgf))) {
+	fclose (msgf);		/* all good, close the msg file now */
+				/* write new metadata, index, and status */
+	local->metaseq = local->indexseq = local->statusseq = seq;
+	if (ret = (mix_meta_update (astream) &&
+		   mix_index_update (astream,idxf,LONGT))) {
+				/* success, delete if doing a move */
+	  if (options & CP_MOVE)
+	    for (i = 1; i <= stream->nmsgs; i++)
+	      if ((elt = mail_elt (stream,i))->sequence) {
+		elt->deleted = T;
+		if (!stream->rdonly) elt->private.mod = LOCAL->statusseq = seq;
+		MM_FLAGS (stream,elt->msgno);
+	      }
+				/* done with status file now */
+	  mix_status_update (astream,statf,LONGT);
+				/* return sets if doing COPYUID */
+	  if (cu) (*cu) (stream,mailbox,astream->uid_validity,source,dest);
+	  source = dest = NIL;	/* don't free these sets now */
+	}
+      }
+      else {			/* error */
+	if (errno) {		/* output error message if system call error */
+	  sprintf (tmp,"Message copy failed: %.80s",strerror (errno));
+	  MM_LOG (tmp,ERROR);
+	}
+	ftruncate (fd,size);	/* revert file */
+	close (fd);		/* make sure that fclose doesn't corrupt us */
+	fclose (msgf);		/* free the stdio resources */
+      }
+				/* flush any sets remaining */
+      mail_free_searchset (&source);
+      mail_free_searchset (&dest);
+    }
+    else {			/* message file open failed */
+      sprintf (tmp,"Error opening copy message file: %.80s",
+	       strerror (errno));
+      MM_LOG (tmp,ERROR);
+      ret = NIL;
+    }
+    MM_NOCRITICAL (stream);
+  }
+  else MM_LOG ("Can't open copy mailbox",ERROR);
+  if (statf) fclose (statf);	/* close status if still open */
+  if (idxf) fclose (idxf);	/* close index if still open */
+				/* finished with append stream */
+  if (astream) mail_close (astream);
+  return ret;			/* return state */
+}
+
+/* MIX mail append message from stringstruct
+ * Accepts: MAIL stream
+ *	    destination mailbox
+ *	    append callback
+ *	    data for callback
+ * Returns: T if append successful, else NIL
+ */
+
+long mix_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data)
+{
+  STRING *message;
+  char *flags,*date,tmp[MAILTMPLEN];
+				/* N.B.: can't use LOCAL->buf for tmp */
+  long ret = mix_isvalid (mailbox,tmp);
+				/* default stream to prototype */
+  if (!stream) stream = user_flags (&mixproto);
+  if (!ret) switch (errno) {	/* if not valid mailbox */
+  case ENOENT:			/* no such file? */
+    if (ret = compare_cstring (mailbox,"INBOX") ?
+	NIL : mix_create (NIL,"INBOX"))
+      break;
+    MM_NOTIFY (stream,"[TRYCREATE] Must create mailbox before append",NIL);
+    break;
+  default:
+    sprintf (tmp,"Not a MIX-format mailbox: %.80s",mailbox);
+    MM_LOG (tmp,ERROR);
+    break;
+  }
+
+				/* get first message */
+  if (ret && MM_APPEND (af) (stream,data,&flags,&date,&message)) {
+    MAILSTREAM *astream;
+    FILE *idxf = NIL;
+    FILE *msgf = NIL;
+    FILE *statf = NIL;
+    if (ret = ((astream = mail_open (NIL,mailbox,OP_SILENT)) &&
+	       !astream->rdonly &&
+	       (((MIXLOCAL *) astream->local)->expok = T) &&
+	       (statf = mix_parse (astream,&idxf,LONGT,NIL))) ?
+	LONGT : NIL) {
+      int fd;
+      unsigned long size,hdrsize;
+      MESSAGECACHE elt;
+      MIXLOCAL *local = (MIXLOCAL *) astream->local;
+      unsigned long seq = mix_modseq (local->metaseq);
+				/* make sure new modseq fits */
+      if (local->indexseq > seq) seq = local->indexseq + 1;
+      if (local->statusseq > seq) seq = local->statusseq + 1;
+				/* calculate size of per-message header */
+      sprintf (local->buf,MSRFMT,MSGTOK,0,0,0,0,0,0,0,'+',0,0,0);
+      hdrsize = strlen (local->buf);
+      MM_CRITICAL (astream);	/* go critical */
+      astream->silent = T;	/* no events here */
+				/* open data file */
+      if (msgf = mix_data_open (astream,&fd,&size,hdrsize + SIZE (message))) {
+	appenduid_t au = (appenduid_t) mail_parameters (NIL,GET_APPENDUID,NIL);
+	SEARCHSET *dst = au ? mail_newsearchset () : NIL;
+	while (ret && message) {/* while good to go and have messages */
+	  errno = NIL;		/* in case one of these causes failure */
+				/* guard against zero-length */
+	  if (!(ret = SIZE (message)))
+	    MM_LOG ("Append of zero-length message",ERROR);
+	  else if (date && !(ret = mail_parse_date (&elt,date))) {
+	    sprintf (tmp,"Bad date in append: %.80s",date);
+	    MM_LOG (tmp,ERROR);
+	  }
+	  else {
+	    if (!date) {	/* if date not specified, use now */
+	      internal_date (tmp);
+	      mail_parse_date (&elt,tmp);
+	    }
+	    ret = mix_append_msg (astream,msgf,flags,&elt,message,dst,seq) &&
+	      MM_APPEND (af) (stream,data,&flags,&date,&message);
+	  }
+	}
+
+				/* finish write if success */
+	if (ret && (ret = !fflush (msgf))) {
+	  fclose (msgf);	/* all good, close the msg file now */
+				/* write new metadata, index, and status */
+	  local->metaseq = local->indexseq = local->statusseq = seq;
+	  if ((ret = (mix_meta_update (astream) &&
+		      mix_index_update (astream,idxf,LONGT) &&
+		      mix_status_update (astream,statf,LONGT))) && au) {
+	      (*au) (mailbox,astream->uid_validity,dst);
+	      dst = NIL;	/* don't free this set now */
+	  }
+	}
+	else {			/* failure */
+	  if (errno) {		/* output error message if system call error */
+	    sprintf (tmp,"Message append failed: %.80s",strerror (errno));
+	    MM_LOG (tmp,ERROR);
+	  }
+	  ftruncate (fd,size);	/* revert all writes to file*/
+	  close (fd);		/* make sure that fclose doesn't corrupt us */
+	  fclose (msgf);	/* free the stdio resources */
+	}
+				/* flush any set remaining */
+	mail_free_searchset (&dst);
+      }
+      else {			/* message file open failed */
+	sprintf (tmp,"Error opening append message file: %.80s",
+		 strerror (errno));
+	MM_LOG (tmp,ERROR);
+	ret = NIL;
+      }
+      MM_NOCRITICAL (astream);	/* release critical */
+    }
+    else MM_LOG ("Can't open append mailbox",ERROR);
+    if (statf) fclose (statf);	/* close status if still open */
+    if (idxf) fclose (idxf);	/* close index if still open */
+    if (astream) mail_close (astream);
+  }
+  return ret;
+}
+
+/* MIX mail append single message
+ * Accepts: MAIL stream
+ *	    flags for new message if non-NIL
+ *	    elt with source date if non-NIL
+ *	    stringstruct of message text
+ *	    searchset to place UID
+ *	    modseq of message
+ * Returns: T if success, NIL if failure
+ */
+
+long mix_append_msg (MAILSTREAM *stream,FILE *f,char *flags,MESSAGECACHE *delt,
+		     STRING *msg,SEARCHSET *set,unsigned long seq)
+{
+  MESSAGECACHE *elt;
+  int c,cs;
+  unsigned long i,j,k,uf,hoff;
+  long sf;
+  stream->kwd_create = NIL;	/* don't copy unknown keywords */
+  sf = mail_parse_flags (stream,flags,&uf);
+				/* swell the cache */
+  mail_exists (stream,++stream->nmsgs);
+				/* assign new UID from metadata */
+  (elt = mail_elt (stream,stream->nmsgs))->private.uid = ++stream->uid_last;
+  elt->private.mod = seq;	/* set requested modseq in status */
+  elt->rfc822_size = SIZE (msg);/* copy message size and date to index */
+  elt->year = delt->year; elt->month = delt->month; elt->day = delt->day;
+  elt->hours = delt->hours; elt->minutes = delt->minutes;
+  elt->seconds = delt->seconds; elt->zoccident = delt->zoccident;
+  elt->zhours = delt->zhours; elt->zminutes = delt->zminutes;
+  /*
+   * Do NOT set elt->valid here!  mix_status_update() uses it to determine
+   * whether a message should be marked as old.
+   */
+  if (sf&fSEEN) elt->seen = T;	/* copy flags to status */
+  if (sf&fDELETED) elt->deleted = T;
+  if (sf&fFLAGGED) elt->flagged = T;
+  if (sf&fANSWERED) elt->answered = T;
+  if (sf&fDRAFT) elt->draft = T;
+  elt->user_flags |= uf;
+				/* message is in new message file */
+  elt->private.spare.data = LOCAL->newmsg;
+
+				/* offset to message internal header */
+  elt->private.special.offset = ftell (f);
+				/* build header for message */
+  fprintf (f,MSRFMT,MSGTOK,elt->private.uid,
+	   elt->year + BASEYEAR,elt->month,elt->day,
+	   elt->hours,elt->minutes,elt->seconds,
+	   elt->zoccident ? '-' : '+',elt->zhours,elt->zminutes,
+	   elt->rfc822_size);
+				/* offset to header from  internal header */
+  elt->private.msg.header.offset = ftell (f) - elt->private.special.offset;
+  for (cs = 0; SIZE (msg); ) {	/* copy message */
+    if (elt->private.msg.header.text.size) {
+      if (msg->cursize)		/* blat entire chunk if have it */
+	for (j = msg->cursize; j; j -= k)
+	  if (!(k = fwrite (msg->curpos,1,j,f))) return NIL;
+      SETPOS (msg,GETPOS (msg) + msg->cursize);
+    }
+    else {			/* still searching for delimiter */
+      c = 0xff & SNX (msg);	/* get source character */
+      if (putc (c,f) == EOF) return NIL;
+      switch (cs) {		/* decide what to do based on state */
+      case 0:			/* previous char ordinary */
+	if (c == '\015') cs = 1;/* advance if CR */
+	break;
+      case 1:			/* previous CR, advance if LF */
+	cs = (c == '\012') ? 2 : 0;
+	break;
+      case 2:			/* previous CRLF, advance if CR */
+	cs = (c == '\015') ? 3 : 0;
+	break;
+      case 3:			/* previous CRLFCR, done if LF */
+	if (c == '\012') elt->private.msg.header.text.size =
+			   elt->rfc822_size - SIZE (msg);
+	cs = 0;			/* reset mechanism */
+	break;
+      }
+    }
+  }
+				/* if no delimiter, header is entire msg */
+  if (!elt->private.msg.header.text.size)
+    elt->private.msg.header.text.size = elt->rfc822_size;
+				/* add this message to set */
+  mail_append_set (set,elt->private.uid);
+  return LONGT;			/* success */
+}
+
+/* MIX mail read metadata, index, and status
+ * Accepts: MAIL stream
+ *	    returned index file
+ *	    index file flags (non-NIL if want to add/remove messages)
+ *	    status file flags (non-NIL if want to update elt->valid and old)
+ * Returns: open status file, or NIL if failure
+ *
+ * Note that this routine can return an open index file even if it fails!
+ */
+
+static char *shortmsg =
+  "message %lu (UID=%.08lx) truncated by %lu byte(s) (%lu < %lu)";
+
+FILE *mix_parse (MAILSTREAM *stream,FILE **idxf,long iflags,long sflags)
+{
+  int fd;
+  unsigned long i;
+  char *s,*t;
+  struct stat sbuf;
+  FILE *statf = NIL;
+  short metarepairneeded = 0;
+  short indexrepairneeded = 0;
+  short silent = stream->silent;
+  *idxf = NIL;			/* in case error */
+				/* readonly means no updates */
+  if (stream->rdonly) iflags = sflags = NIL;
+				/* open index file */
+  if ((fd = open (LOCAL->index,iflags ? O_RDWR : O_RDONLY,NIL)) < 0)
+    MM_LOG ("Error opening mix index file",ERROR);
+				/* acquire exclusive access and FILE */
+  else if (!flock (fd,iflags ? LOCK_EX : LOCK_SH) &&
+	   !(*idxf = fdopen (fd,iflags ? "r+b" : "rb"))) {
+    MM_LOG ("Error obtaining stream on mix index file",ERROR);
+    flock (fd,LOCK_UN);		/* relinquish lock */
+    close (fd);
+  }
+
+				/* slurp metadata */
+  else if (s = mix_meta_slurp (stream,&i)) {
+    unsigned long j = 0;	/* non-zero if UIDVALIDITY/UIDLAST changed */
+    if (i != LOCAL->metaseq) {	/* metadata changed? */
+      char *t,*k;
+      LOCAL->metaseq = i;	/* note new metadata sequence */
+      while (s && *s) {		/* parse entire metadata file */
+				/* locate end of line */
+	if (s = strstr (t = s,"\015\012")) {
+	  *s = '\0';		/* tie off line */
+	  s += 2;		/* skip past CRLF */
+	  switch (*t++) {	/* parse line */
+	  case 'V':		/* UIDVALIDITY */
+	    if (!isxdigit (*t) || !(i = strtoul (t,&t,16))) {
+	      MM_LOG ("Error in mix metadata file UIDVALIDITY record",ERROR);
+	      return NIL;	/* give up */
+	    }
+	    if (i != stream->uid_validity) j = stream->uid_validity = i;
+	    break;
+	  case 'L':		/* new UIDLAST */
+	    if (!isxdigit (*t)) {
+	      MM_LOG ("Error in mix metadata file UIDLAST record",ERROR);
+	      return NIL;	/* give up */
+	    }
+	    if ((i = strtoul (t,&t,16)) != stream->uid_last)
+	      j = stream->uid_last = i;
+	    break;
+	  case 'N':		/* new message file */
+	    if (!isxdigit (*t)) {
+	      MM_LOG ("Error in mix metadata file new msg record",ERROR);
+	      return NIL;	/* give up */
+	    }
+	    if ((i = strtoul (t,&t,16)) != stream->uid_last)
+	      LOCAL->newmsg = i;
+	    break;
+	  case 'K':		/* new keyword list */
+	    for (i = 0; t && *t && (i < NUSERFLAGS); ++i) {
+	      if (t = strchr (k = t,' ')) *t++ = '\0';
+				/* make sure keyword non-empty */
+	      if (*k && (strlen (k) <= MAXUSERFLAG)) {
+				/* in case value changes (shouldn't happen) */
+		if (stream->user_flags[i] && strcmp (stream->user_flags[i],k)){
+		  char tmp[MAILTMPLEN];
+		  sprintf (tmp,"flag rename old=%.80s new=%.80s",
+			   stream->user_flags[i],k);
+		  MM_LOG (tmp,WARN);
+		  fs_give ((void **) &stream->user_flags[i]);
+		}
+		if (!stream->user_flags[i]) stream->user_flags[i] = cpystr (k);
+	      }
+	      else break;	/* empty keyword */
+	    }
+	    if ((i < NUSERFLAGS) && stream->user_flags[i]) {
+	      MM_LOG ("Error in mix metadata file keyword record",ERROR);
+	      return NIL;	/* give up */
+	    }
+	    else if (i == NUSERFLAGS) stream->kwd_create = NIL;
+	    break;
+	  }
+	}
+	if (t && *t) {		/* junk in line */
+	  MM_LOG ("Error in mix metadata record",ERROR);
+	  return NIL;		/* give up */
+	}
+      }
+    }
+
+				/* get sequence */
+    if (!(i = mix_read_sequence (*idxf)) || (i < LOCAL->indexseq)) {
+      MM_LOG ("Error in mix index file sequence record",ERROR);
+      return NIL;		/* give up */
+    }
+				/* sequence changed from last time? */
+    else if (j || (i > LOCAL->indexseq)) {
+      unsigned long uid,nmsgs,curfile,curfilesize,curpos;
+      char *t,*msg,tmp[MAILTMPLEN];
+				/* start with no messages */
+      curfile = curfilesize = curpos = nmsgs = 0;
+				/* update sequence iff expunging OK */
+      if (LOCAL->expok) LOCAL->indexseq = i;
+				/* get first elt */
+      while ((s = mix_read_record (*idxf,LOCAL->buf,LOCAL->buflen,"index")) &&
+	     *s)
+	switch (*s) {
+	case ':':		/* message record */
+	  if (!(isxdigit (*++s) && (uid = strtoul (s,&t,16)))) msg = "UID";
+	  else if (!((*t++ == ':') && isdigit (*t) && isdigit (t[1]) &&
+		     isdigit (t[2]) && isdigit (t[3]) && isdigit (t[4]) &&
+		     isdigit (t[5]) && isdigit (t[6]) && isdigit (t[7]) &&
+		     isdigit (t[8]) && isdigit (t[9]) && isdigit (t[10]) &&
+		     isdigit (t[11]) && isdigit (t[12]) && isdigit (t[13]) &&
+		     ((t[14] == '+') || (t[14] == '-')) && 
+		     isdigit (t[15]) && isdigit (t[16]) && isdigit (t[17]) &&
+		     isdigit (t[18]))) msg = "internaldate";
+	  else if ((*(s = t+19) != ':') || !isxdigit (*++s)) msg = "size";
+	  else {
+	    unsigned int y = (((*t - '0') * 1000) + ((t[1] - '0') * 100) +
+			      ((t[2] - '0') * 10) + t[3] - '0') - BASEYEAR;
+	    unsigned int m = ((t[4] - '0') * 10) + t[5] - '0';
+	    unsigned int d = ((t[6] - '0') * 10) + t[7] - '0';
+	    unsigned int hh = ((t[8] - '0') * 10) + t[9] - '0';
+	    unsigned int mm = ((t[10] - '0') * 10) + t[11] - '0';
+	    unsigned int ss = ((t[12] - '0') * 10) + t[13] - '0';
+	    unsigned int z = (t[14] == '-') ? 1 : 0;
+	    unsigned int zh = ((t[15] - '0') * 10) + t[16] - '0';
+	    unsigned int zm = ((t[17] - '0') * 10) + t[18] - '0';
+	    unsigned long size = strtoul (s,&s,16);
+	    if ((*s++ == ':') && isxdigit (*s)) {
+	      unsigned long file = strtoul (s,&s,16);
+	      if ((*s++ == ':') && isxdigit (*s)) {
+		unsigned long pos = strtoul (s,&s,16);
+		if ((*s++ == ':') && isxdigit (*s)) {
+		  unsigned long hpos = strtoul (s,&s,16);
+		  if ((*s++ == ':') && isxdigit (*s)) {
+		    unsigned long hsiz = strtoul (s,&s,16);
+		    if (uid > stream->uid_last) {
+		      sprintf (tmp,"mix index invalid UID (%08lx < %08lx)",
+			       uid,stream->uid_last);
+		      if (stream->rdonly) {
+			MM_LOG (tmp,ERROR);
+			return NIL;
+		      }
+		      strcat (tmp,", repaired");
+		      MM_LOG (tmp,WARN);
+		      stream->uid_last = uid;
+		      metarepairneeded = T;
+		    }
+
+				/* ignore expansion values */
+		    if (*s++ == ':') {
+		      MESSAGECACHE *elt;
+		      ++nmsgs;	/* this is another mesage */
+				/* within current known range of messages? */
+		      while (nmsgs <= stream->nmsgs) {
+				/* yes, get corresponding elt */
+			elt = mail_elt (stream,nmsgs);
+				/* existing message with matching data? */
+			if (uid == elt->private.uid) {
+				/* beware of Dracula's resurrection */
+			  if (elt->private.ghost) {
+			    sprintf (tmp,"mix index data unexpunged UID: %lx",
+				     uid);
+			    MM_LOG (tmp,ERROR);
+			    return NIL;
+			  }
+				/* also of static data changing */
+			  if ((size != elt->rfc822_size) ||
+			      (file != elt->private.spare.data) ||
+			      (pos != elt->private.special.offset) ||
+			      (hpos != elt->private.msg.header.offset) ||
+			      (hsiz != elt->private.msg.header.text.size) ||
+			      (y != elt->year) || (m != elt->month) ||
+			      (d != elt->day) || (hh != elt->hours) ||
+			      (mm != elt->minutes) || (ss != elt->seconds) ||
+			      (z != elt->zoccident) || (zh != elt->zhours) ||
+			      (zm != elt->zminutes)) {
+			    sprintf (tmp,"mix index data mismatch: %lx",uid);
+			    MM_LOG (tmp,ERROR);
+			    return NIL;
+			  }
+			  break;
+			}
+				/* existing msg with lower UID is expunged */
+			else if (uid > elt->private.uid) {
+			  if (LOCAL->expok) mail_expunged (stream,nmsgs);
+			  else {/* message expunged, but not yet for us */
+			    ++nmsgs;
+			    elt->private.ghost = T;
+			  }
+			}
+			else {	/* unexpected message record */
+			  sprintf (tmp,"mix index UID mismatch (%lx < %lx)",
+				   uid,elt->private.uid);
+			  MM_LOG (tmp,ERROR);
+			  return NIL;
+			}
+		      }
+
+				/* time to create a new message? */
+		      if (nmsgs > stream->nmsgs) {
+				/* defer announcing until later */
+			stream->silent = T;
+			mail_exists (stream,nmsgs);
+			stream->silent = silent;
+			(elt = mail_elt (stream,nmsgs))->recent = T;
+			elt->private.uid = uid; elt->rfc822_size = size;
+			elt->private.spare.data = file;
+			elt->private.special.offset = pos;
+			elt->private.msg.header.offset = hpos;
+			elt->private.msg.header.text.size = hsiz;
+			elt->year = y; elt->month = m; elt->day = d;
+			elt->hours = hh; elt->minutes = mm;
+			elt->seconds = ss; elt->zoccident = z;
+			elt->zhours = zh; elt->zminutes = zm;
+				/* message in same file? */
+			if (curfile == file) {
+			  if (pos < curpos) {
+			    MESSAGECACHE *plt = mail_elt (stream,elt->msgno-1);
+				/* uh-oh, calculate delta? */
+			    i = curpos - pos;
+			    sprintf (tmp,shortmsg,plt->msgno,plt->private.uid,
+				     i,pos,curpos);
+				/* possible to fix? */
+			    if (!stream->rdonly && LOCAL->expok &&
+				(i < plt->rfc822_size)) {
+			      plt->rfc822_size -= i;
+			      if (plt->rfc822_size <
+				  plt->private.msg.header.text.size)
+				plt->private.msg.header.text.size =
+				  plt->rfc822_size;
+			      strcat (tmp,", repaired");
+			      indexrepairneeded = T;
+			    }
+			    MM_LOG (tmp,WARN);
+			  }
+			}
+			else {	/* new file, restart */
+			  if (stat (mix_file_data (LOCAL->buf,stream->mailbox,
+						   curfile = file),&sbuf)) {
+			    sprintf (tmp,"Missing mix data file: %.500s",
+				     LOCAL->buf);
+			    MM_LOG (tmp,ERROR);
+			    return NIL;
+			  }
+			  curfile = file;
+			  curfilesize = sbuf.st_size;
+			}
+
+				/* position of message in file */
+			curpos = pos + elt->private.msg.header.offset +
+			  elt->rfc822_size;
+				/* short file? */
+			if (curfilesize < curpos) {
+				/* uh-oh, calculate delta? */
+			    i = curpos - curfilesize;
+			    sprintf (tmp,shortmsg,elt->msgno,elt->private.uid,
+				     i,curfilesize,curpos);
+				/* possible to fix? */
+			    if (!stream->rdonly && LOCAL->expok &&
+				(i < elt->rfc822_size)) {
+			      elt->rfc822_size -= i;
+			      if (elt->rfc822_size <
+				  elt->private.msg.header.text.size)
+				elt->private.msg.header.text.size =
+				  elt->rfc822_size;
+			      strcat (tmp,", repaired");
+			      indexrepairneeded = T;
+			    }
+			    MM_LOG (tmp,WARN);
+			}
+		      }
+		      break;
+		    }
+		    else msg = "expansion";
+		  }
+		  else msg = "header size";
+		}
+		else msg = "header position";
+	      }
+	      else msg = "message position";
+	    }
+	    else msg = "file#";
+	  }
+	  sprintf (tmp,"Error in %s in mix index file: %.500s",msg,s);
+	  MM_LOG (tmp,ERROR);
+	  return NIL;
+	default:
+	  sprintf (tmp,"Unknown record in mix index file: %.500s",s);
+	  MM_LOG (tmp,ERROR);
+	  return NIL;
+	}
+      if (!s) return NIL;	/* barfage from mix_read_record() */
+				/* expunge trailing messages not in index */
+      if (LOCAL->expok) while (nmsgs < stream->nmsgs)
+	mail_expunged (stream,stream->nmsgs);
+    }
+
+				/* repair metadata and index if needed */
+    if ((metarepairneeded ? mix_meta_update (stream) : T) &&
+	(indexrepairneeded ? mix_index_update (stream,*idxf,NIL) : T)) {
+      MESSAGECACHE *elt;
+      int fd;
+      unsigned long uid,uf,sf,mod;
+      char *s;
+      int updatep = NIL;
+				/* open status file */
+      if ((fd = open (LOCAL->status,
+		      stream->rdonly ? O_RDONLY : O_RDWR,NIL)) < 0)
+	MM_LOG ("Error opening mix status file",ERROR);
+				/* acquire exclusive access and FILE */
+      else if (!flock (fd,stream->rdonly ? LOCK_SH : LOCK_EX) &&
+	       !(statf = fdopen (fd,stream->rdonly ? "rb" : "r+b"))) {
+	MM_LOG ("Error obtaining stream on mix status file",ERROR);
+	flock (fd,LOCK_UN);	/* relinquish lock */
+	close (fd);
+      }
+				/* get sequence */
+      else if (!(i = mix_read_sequence (statf)) ||
+	       ((i < LOCAL->statusseq) && stream->nmsgs && (i != 1))) {
+	sprintf (LOCAL->buf,
+		 "Error in mix status sequence record, i=%lx, seq=%lx",
+		 i,LOCAL->statusseq);
+	MM_LOG (LOCAL->buf,ERROR);
+      }
+				/* sequence changed from last time? */
+      else if (i != LOCAL->statusseq) {
+				/* update sequence, get first elt */
+	if (i > LOCAL->statusseq) LOCAL->statusseq = i;
+	if (stream->nmsgs) {
+	  elt = mail_elt (stream,i = 1);
+
+				/* read message records */
+	  while ((t = s = mix_read_record (statf,LOCAL->buf,LOCAL->buflen,
+					   "status")) && *s && (*s++ == ':') &&
+		 isxdigit (*s)) {
+	    uid = strtoul (s,&s,16);
+	    if ((*s++ == ':') && isxdigit (*s)) {
+	      uf = strtoul (s,&s,16);
+	      if ((*s++ == ':') && isxdigit (*s)) {
+		sf = strtoul (s,&s,16);
+		if ((*s++ == ':') && isxdigit (*s)) {
+		  mod = strtoul (s,&s,16);
+				/* ignore expansion values */
+		  if (*s++ == ':') {
+				/* need to move ahead to next elt? */
+		    while ((uid > elt->private.uid) && (i < stream->nmsgs))
+		      elt = mail_elt (stream,++i);
+				/* update elt if altered */
+		    if ((uid == elt->private.uid) &&
+			(!elt->valid || (mod != elt->private.mod))) {
+		      elt->user_flags = uf;
+		      elt->private.mod = mod;
+		      elt->seen = (sf & fSEEN) ? T : NIL;
+		      elt->deleted = (sf & fDELETED) ? T : NIL;
+		      elt->flagged = (sf & fFLAGGED) ? T : NIL;
+		      elt->answered = (sf & fANSWERED) ? T : NIL;
+		      elt->draft = (sf & fDRAFT) ? T : NIL;
+				/* announce if altered existing message */
+		      if (elt->valid) MM_FLAGS (stream,elt->msgno);
+				/* first time, is old message? */
+		      else if (sf & fOLD) {
+				/* yes, clear recent and set valid */
+			elt->recent = NIL;
+			elt->valid = T;
+		      }
+				/* recent, allowed to update its status? */
+		      else if (sflags) {
+				/* yes, set valid and check in status */
+			elt->valid = T;
+			elt->private.mod = mix_modseq (elt->private.mod);
+			updatep = T;
+		      }
+		      /* leave valid unset and recent if sflags not set */
+		    }
+		    continue;	/* everything looks good */
+		  }
+		}
+	      }
+	    }
+	    break;		/* error somewhere */
+	  }
+
+	  if (t && *t) {	/* non-null means bogus record */
+	    char msg[MAILTMPLEN];
+	    sprintf (msg,"Error in mix status file message record%s: %.80s",
+		     stream->rdonly ? "" : ", fixing",t);
+	    MM_LOG (msg,WARN);
+				/* update it if not readonly */
+	    if (!stream->rdonly) updatep = T;
+	  }
+	  if (updatep) {		/* need to update? */
+	    LOCAL->statusseq = mix_modseq (LOCAL->statusseq);
+	    mix_status_update (stream,statf,LONGT);
+	  }
+	}
+      }
+    }
+  }
+  if (statf) {			/* still happy? */
+    unsigned long j;
+    stream->silent = silent;	/* now notify upper level */
+    mail_exists (stream,stream->nmsgs);
+    for (i = 1, j = 0; i <= stream->nmsgs; ++i)
+      if (mail_elt (stream,i)->recent) ++j;
+    mail_recent (stream,j);
+  }
+  return statf;
+}
+
+/* MIX metadata file routines */
+
+/* MIX read metadata
+ * Accepts: MAIL stream
+ *	    return pointer for modseq
+ * Returns: pointer to metadata after modseq or NIL if failure
+ */
+
+char *mix_meta_slurp (MAILSTREAM *stream,unsigned long *seq)
+{
+  struct stat sbuf;
+  char *s;
+  char *ret = NIL;
+  if (fstat (LOCAL->mfd,&sbuf))
+    MM_LOG ("Error obtaining size of mix metatdata file",ERROR);
+  if (sbuf.st_size > LOCAL->buflen) {
+				/* should be just a few dozen bytes */
+    if (sbuf.st_size > METAMAX) fatal ("absurd mix metadata file size");
+    fs_give ((void **) &LOCAL->buf);
+    LOCAL->buf = (char *) fs_get ((LOCAL->buflen = sbuf.st_size) + 1);
+  }
+				/* read current metadata file */
+  LOCAL->buf[sbuf.st_size] = '\0';
+  if (lseek (LOCAL->mfd,0,L_SET) ||
+      (read (LOCAL->mfd,s = LOCAL->buf,sbuf.st_size) != sbuf.st_size))
+    MM_LOG ("Error reading mix metadata file",ERROR);
+  else if ((*s != 'S') || !isxdigit (s[1]) ||
+	   ((*seq = strtoul (s+1,&s,16)) < LOCAL->metaseq) ||
+	   (*s++ != '\015') || (*s++ != '\012'))
+    MM_LOG ("Error in mix metadata file sequence record",ERROR);
+  else ret = s;
+  return ret;
+}
+
+/* MIX update metadata
+ * Accepts: MAIL stream
+ * Returns: T on success, NIL if error
+ *
+ * Index MUST be locked!!
+ */
+
+long mix_meta_update (MAILSTREAM *stream)
+{
+  long ret;
+				/* do nothing if stream readonly */
+  if (stream->rdonly) ret = LONGT;
+  else {
+    unsigned char c,*s,*ss,*t;
+    unsigned long i;
+    /* The worst-case metadata is limited to:
+     *    4 * (1 + 8 + 2) + (NUSERFLAGS * (MAXUSERFLAG + 1))
+     * which comes out to 1994 octets.  This is much smaller than the normal
+     * CHUNKSIZE definition of 64K, and CHUNKSIZE is the smallest size of
+     * LOCAL->buf.
+     *
+     * If more stuff gets added to the metadata, or if you change the value
+     * of NUSERFLAGS, MAXUSERFLAG or CHUNKSIZE, be sure to recalculate the
+     * above assertation.
+     */
+    sprintf (LOCAL->buf,SEQFMT,LOCAL->metaseq = mix_modseq (LOCAL->metaseq));
+    sprintf (LOCAL->buf + strlen (LOCAL->buf),MTAFMT,
+	     stream->uid_validity,stream->uid_last,LOCAL->newmsg);
+    for (i = 0, c = 'K', s = ss = LOCAL->buf + strlen (LOCAL->buf);
+	 (i < NUSERFLAGS) && (t = stream->user_flags[i]); ++i) {
+      if (!*t) fatal ("impossible empty keyword");
+      *s++ = c;			/* write delimiter */
+      while (*t) *s++ = *t++;	/* write keyword */
+      c = ' ';			/* delimiter is now space */
+    }
+    if (s != ss) {		/* tie off keywords line */
+      *s++ = '\015'; *s++ = '\012';
+    }
+				/* calculate length of metadata */
+    if ((i = s - LOCAL->buf) > LOCAL->buflen)
+      fatal ("impossible buffer overflow");
+    lseek (LOCAL->mfd,0,L_SET);	/* rewind file */
+				/* write new metadata */
+    ret = (write (LOCAL->mfd,LOCAL->buf,i) == i) ? LONGT : NIL;
+    ftruncate (LOCAL->mfd,i);	/* and tie off at that point */
+  }
+  return ret;
+}
+
+/* MIX index file routines */
+
+
+/* MIX update index
+ * Accepts: MAIL stream
+ *	    open FILE
+ *	    expansion check flag
+ * Returns: T on success, NIL if error
+ */
+
+long mix_index_update (MAILSTREAM *stream,FILE *idxf,long flag)
+{
+  unsigned long i;
+  long ret = LONGT;
+  if (!stream->rdonly) {	/* do nothing if stream readonly */
+    if (flag) {			/* need to do expansion check? */
+      char tmp[MAILTMPLEN];
+      size_t size;
+      struct stat sbuf;
+				/* calculate file size we need */
+      for (i = 1, size = 0; i <= stream->nmsgs; ++i)
+	if (!mail_elt (stream,i)->private.ghost) ++size;
+      if (size) {		/* Winston Smith's first dairy entry */
+	sprintf (tmp,IXRFMT,0,14,4,4,13,0,0,'+',0,0,0,0,0,0,0);
+	size *= strlen (tmp);
+      }
+				/* calculate file size we need */
+      sprintf (tmp,SEQFMT,LOCAL->indexseq);
+      size += strlen (tmp);
+				/* get current file size */
+      if (fstat (fileno (idxf),&sbuf)) {
+	MM_LOG ("Error getting size of mix index file",ERROR);
+	ret = NIL;
+      }
+				/* need to write additional space? */
+      else if (sbuf.st_size < size) {
+	void *buf = fs_get (size -= sbuf.st_size);
+	memset (buf,0,size);
+	if (fseek (idxf,0,SEEK_END) || (fwrite (buf,1,size,idxf) != size) ||
+	    fflush (idxf)) {
+	  fseek (idxf,sbuf.st_size,SEEK_SET);
+	  ftruncate (fileno (idxf),sbuf.st_size);
+	  MM_LOG ("Error extending mix index file",ERROR);
+	  ret = NIL;
+	}
+	fs_give ((void **) &buf);
+      }
+    }
+
+    if (ret) {			/* if still good to go */
+      rewind (idxf);		/* let's start at the very beginning */
+				/* write modseq first */
+      fprintf (idxf,SEQFMT,LOCAL->indexseq);
+				/* then write all messages */
+      for (i = 1; ret && (i <= stream->nmsgs); i++) {
+	MESSAGECACHE *elt = mail_elt (stream,i);
+	if (!elt->private.ghost)/* only write living messages */
+	  fprintf (idxf,IXRFMT,elt->private.uid,
+		   elt->year + BASEYEAR,elt->month,elt->day,
+		   elt->hours,elt->minutes,elt->seconds,
+		   elt->zoccident ? '-' : '+',elt->zhours,elt->zminutes,
+		   elt->rfc822_size,elt->private.spare.data,
+		   elt->private.special.offset,
+		   elt->private.msg.header.offset,
+		   elt->private.msg.header.text.size);
+	if (ferror (idxf)) {
+	  MM_LOG ("Error updating mix index file",ERROR);
+	  ret = NIL;
+	}
+      }
+      if (fflush (idxf)) {
+	MM_LOG ("Error flushing mix index file",ERROR);
+	ret = NIL;
+      }
+      if (ret) ftruncate (fileno (idxf),ftell (idxf));
+    }
+  }
+  return ret;
+}
+
+/* MIX status file routines */
+
+
+/* MIX update status
+ * Accepts: MAIL stream
+ *	    pointer to open FILE
+ *	    expansion check flag
+ * Returns: T on success, NIL if error
+ */
+
+long mix_status_update (MAILSTREAM *stream,FILE *statf,long flag)
+{
+  unsigned long i;
+  char tmp[MAILTMPLEN];
+  long ret = LONGT;
+  if (!stream->rdonly) {	/* do nothing if stream readonly */
+    if (flag) {			/* need to do expansion check? */
+      char tmp[MAILTMPLEN];
+      size_t size;
+      struct stat sbuf;
+				/* calculate file size we need */
+      for (i = 1, size = 0; i <= stream->nmsgs; ++i)
+	if (!mail_elt (stream,i)->private.ghost) ++size;
+      if (size) {		/* number of living messages */
+	sprintf (tmp,STRFMT,0,0,0,0);
+	size *= strlen (tmp);
+      }
+      sprintf (tmp,SEQFMT,LOCAL->statusseq);
+      size += strlen (tmp);
+				/* get current file size */
+      if (fstat (fileno (statf),&sbuf)) {
+	MM_LOG ("Error getting size of mix status file",ERROR);
+	ret = NIL;
+      }
+				/* need to write additional space? */
+      else if (sbuf.st_size < size) {
+	void *buf = fs_get (size -= sbuf.st_size);
+	memset (buf,0,size);
+	if (fseek (statf,0,SEEK_END) || (fwrite (buf,1,size,statf) != size) ||
+	    fflush (statf)) {
+	  fseek (statf,sbuf.st_size,SEEK_SET);
+	  ftruncate (fileno (statf),sbuf.st_size);
+	  MM_LOG ("Error extending mix status file",ERROR);
+	  ret = NIL;
+	}
+	fs_give ((void **) &buf);
+      }
+    }
+
+    if (ret) {			/* if still good to go */
+      rewind (statf);		/* let's start at the very beginning */
+				/* write sequence */
+      fprintf (statf,SEQFMT,LOCAL->statusseq);
+				/* write message status records */
+      for (i = 1; ret && (i <= stream->nmsgs); ++i) {
+	MESSAGECACHE *elt = mail_elt (stream,i);
+				/* make sure all messages have a modseq */
+	if (!elt->private.mod) elt->private.mod = LOCAL->statusseq;
+	if (!elt->private.ghost)/* only write living messages */
+	  fprintf (statf,STRFMT,elt->private.uid,elt->user_flags,
+		   (fSEEN * elt->seen) + (fDELETED * elt->deleted) +
+		   (fFLAGGED * elt->flagged) + (fANSWERED * elt->answered) +
+		   (fDRAFT * elt->draft) + (elt->valid ? fOLD : NIL),
+		   elt->private.mod);
+	if (ferror (statf)) {
+	  sprintf (tmp,"Error updating mix status file: %.80s",
+		   strerror (errno));
+	  MM_LOG (tmp,ERROR);
+	  ret = NIL;
+	}
+      }
+      if (ret && fflush (statf)) {
+	MM_LOG ("Error flushing mix status file",ERROR);
+	ret = NIL;
+      }
+      if (ret) ftruncate (fileno (statf),ftell (statf));
+    }
+  }
+  return ret;
+}
+
+/* MIX data file routines */
+
+
+/* MIX open data file
+ * Accepts: MAIL stream
+ *	    pointer to returned fd if success
+ *	    pointer to returned size if success
+ *	    size of new data to be added
+ * Returns: open FILE, or NIL if failure
+ *
+ * The curend test assumes that the last message of the mailbox is the furthest
+ * point that the current data file extends, and thus that is all that needs to
+ * be tested for short file prevention.
+ */
+
+FILE *mix_data_open (MAILSTREAM *stream,int *fd,long *size,
+		     unsigned long newsize)
+{
+  FILE *msgf = NIL;
+  struct stat sbuf;
+  MESSAGECACHE *elt = stream->nmsgs ? mail_elt (stream,stream->nmsgs) : NIL;
+  unsigned long curend = (elt && (elt->private.spare.data == LOCAL->newmsg)) ?
+    elt->private.special.offset + elt->private.msg.header.offset +
+    elt->rfc822_size : 0;
+				/* allow create if curend 0 */
+  if ((*fd = open (mix_file_data (LOCAL->buf,stream->mailbox,LOCAL->newmsg),
+		   O_RDWR | (curend ? NIL : O_CREAT),NIL)) >= 0) {
+    fstat (*fd,&sbuf);		/* get current file size */
+				/* can we use this file? */
+    if ((curend <= sbuf.st_size) &&
+	(!sbuf.st_size || ((sbuf.st_size + newsize) <= MIXDATAROLL)))
+      *size = sbuf.st_size;	/* yes, return current size */
+    else {			/* short file or becoming too long */
+      if (curend > sbuf.st_size) {
+	char tmp[MAILTMPLEN];
+	sprintf (tmp,"short mix message file %.08lx (%ld > %ld), rolling",
+		 LOCAL->newmsg,curend,sbuf.st_size);
+	MM_LOG (tmp,WARN);	/* shouldn't happen */
+      }
+      close (*fd);		/* roll to a new file */
+      while ((*fd = open (mix_file_data
+			  (LOCAL->buf,stream->mailbox,
+			   LOCAL->newmsg = mix_modseq (LOCAL->newmsg)),
+			  O_RDWR | O_CREAT | O_EXCL,sbuf.st_mode)) < 0);
+      *size = 0;		/* brand new file */
+      fchmod (*fd,sbuf.st_mode);/* with same mode as previous file */
+    }
+  }
+  if (*fd >= 0) {		/* have a data file? */
+				/* yes, get stdio and set position */
+    if (msgf = fdopen (*fd,"r+b")) fseek (msgf,*size,SEEK_SET);
+    else close (*fd);		/* fdopen() failed? */
+  }
+  return msgf;			/* return results */
+}
+
+/* MIX open sortcache
+ * Accepts: MAIL stream
+ * Returns: open FILE, or NIL if failure or could only get readonly sortcache
+ */
+
+FILE *mix_sortcache_open (MAILSTREAM *stream)
+{
+  int fd,refwd;
+  unsigned long i,uid,sentdate,fromlen,tolen,cclen,subjlen,msgidlen,reflen;
+  char *s,*t,*msg,tmp[MAILTMPLEN];
+  MESSAGECACHE *elt;
+  SORTCACHE *sc;
+  STRINGLIST *sl;
+  struct stat sbuf;
+  int rdonly = NIL;
+  FILE *srtcf = NIL;
+  mailcache_t mc = (mailcache_t) mail_parameters (NIL,GET_CACHE,NIL);
+  fstat (LOCAL->mfd,&sbuf);
+  if (!stream->nmsgs);		/* do nothing if mailbox empty */
+				/* open sortcache file */
+  else if (((fd = open (LOCAL->sortcache,O_RDWR|O_CREAT,sbuf.st_mode)) < 0) &&
+	   !(rdonly = ((fd = open (LOCAL->sortcache,O_RDONLY,NIL)) >= 0)))
+    MM_LOG ("Error opening mix sortcache file",WARN);
+				/* acquire lock and FILE */
+  else if (!flock (fd,rdonly ? LOCK_SH : LOCK_EX) &&
+	   !(srtcf = fdopen (fd,rdonly ? "rb" : "r+b"))) {
+    MM_LOG ("Error obtaining stream on mix sortcache file",WARN);
+    flock (fd,LOCK_UN);		/* relinquish lock */
+    close (fd);
+  }
+  else if (!(i = mix_read_sequence (srtcf)) || (i < LOCAL->sortcacheseq))
+    MM_LOG ("Error in mix sortcache file sequence record",WARN);
+				/* sequence changed from last time? */
+  else if (i > LOCAL->sortcacheseq) {
+    LOCAL->sortcacheseq = i;	/* update sequence */
+    while ((s = t = mix_read_record (srtcf,LOCAL->buf,LOCAL->buflen,
+				     "sortcache")) && *s &&
+	   (msg = "uid") && (*s++ == ':') && isxdigit (*s)) {
+      uid = strtoul (s,&s,16);
+      if ((*s++ == ':') && isxdigit (*s)) {
+	sentdate = strtoul (s,&s,16);
+	if ((*s++ == ':') && isxdigit (*s)) {
+	  fromlen = strtoul (s,&s,16);
+	  if ((*s++ == ':') && isxdigit (*s)) {
+	    tolen = strtoul (s,&s,16);
+	    if ((*s++ == ':') && isxdigit (*s)) {
+	      cclen = strtoul (s,&s,16);
+	      if ((*s++ == ':') && ((*s == 'R') || (*s == ' ')) &&
+		  isxdigit (s[1])) {
+		refwd = (*s++ == 'R') ? T : NIL;
+		subjlen = strtoul (s,&s,16);
+		if ((*s++ == ':') && isxdigit (*s)) {
+		  msgidlen = strtoul (s,&s,16);
+		  if ((*s++ == ':') && isxdigit (*s)) {
+		    reflen = strtoul (s,&s,16);
+				/* ignore expansion values */
+		    if (*s++ == ':') {
+
+		      if (i = mail_msgno (stream,uid)) {
+			sc = (SORTCACHE *) (*mc) (stream,i,CH_SORTCACHE);
+			sc->size = (elt = mail_elt (stream,i))->rfc822_size;
+			sc->date = sentdate;
+			sc->arrival = elt->day ? mail_longdate (elt) : 1;
+			if (refwd) sc->refwd = T;
+			if (fromlen) {
+			  if (sc->from) fseek (srtcf,fromlen + 2,SEEK_CUR);
+			  else if ((getc (srtcf) != 'F') ||
+				   (fread (sc->from = (char *) fs_get(fromlen),
+					   1,fromlen-1,srtcf) != (fromlen-1))||
+				   (sc->from[fromlen-1] = '\0') ||
+				   (getc (srtcf) != '\015') ||
+				   (getc (srtcf) != '\012')) {
+			    msg = "from data";
+			    break;
+			  }
+			}
+			if (tolen) {
+			  if (sc->to) fseek (srtcf,tolen + 2,SEEK_CUR);
+			  else if ((getc (srtcf) != 'T') ||
+				   (fread (sc->to = (char *) fs_get (tolen),
+					   1,tolen-1,srtcf) != (tolen - 1)) ||
+				   (sc->to[tolen-1] = '\0') ||
+				   (getc (srtcf) != '\015') ||
+				   (getc (srtcf) != '\012')) {
+			    msg = "to data";
+			    break;
+			  }
+			}
+			if (cclen) {
+			  if (sc->cc) fseek (srtcf,cclen + 2,SEEK_CUR);
+			  else if ((getc (srtcf) != 'C') ||
+				   (fread (sc->cc = (char *) fs_get (cclen),
+					   1,cclen-1,srtcf) != (cclen - 1)) ||
+				   (sc->cc[cclen-1] = '\0') ||
+				   (getc (srtcf) != '\015') ||
+				   (getc (srtcf) != '\012')) {
+			    msg = "cc data";
+			    break;
+			  }
+			}
+			if (subjlen) {
+			  if (sc->subject) fseek (srtcf,subjlen + 2,SEEK_CUR);
+			  else if ((getc (srtcf) != 'S') ||
+				     (fread (sc->subject =
+					     (char *) fs_get (subjlen),1,
+					     subjlen-1,srtcf) != (subjlen-1))||
+				   (sc->subject[subjlen-1] = '\0') ||
+				   (getc (srtcf) != '\015') ||
+				   (getc (srtcf) != '\012')) {
+			    msg = "subject data";
+			    break;
+			  }
+			}
+
+			if (msgidlen) {
+			  if (sc->message_id)
+			    fseek (srtcf,msgidlen + 2,SEEK_CUR);
+			  else if ((getc (srtcf) != 'M') ||
+				   (fread (sc->message_id = 
+					   (char *) fs_get (msgidlen),1,
+					   msgidlen-1,srtcf) != (msgidlen-1))||
+				   (sc->message_id[msgidlen-1] = '\0') ||
+				   (getc (srtcf) != '\015') ||
+				   (getc (srtcf) != '\012')) {
+			    msg = "message-id data";
+			    break;
+			  }
+			}
+			if (reflen) {
+			  if (sc->references) fseek(srtcf,reflen + 2,SEEK_CUR);
+				/* make sure it fits */
+			  else {
+			    if (reflen >= LOCAL->buflen) {
+			      fs_give ((void **) &LOCAL->buf);
+			      LOCAL->buf = (char *)
+				fs_get ((LOCAL->buflen = reflen) + 1);
+			      }
+			    if ((getc (srtcf) != 'R') ||
+				(fread (LOCAL->buf,1,reflen-1,srtcf) !=
+				 (reflen - 1)) ||
+				(LOCAL->buf[reflen-1] = '\0') ||
+				(getc (srtcf) != '\015') ||
+				(getc (srtcf) != '\012')) {
+			      msg = "references data";
+			      break;
+			    }
+			    for (s = LOCAL->buf,sl = NIL,
+				   sc->references = mail_newstringlist ();
+				 s && *s; s += i + 1) {
+			      if ((i = strtoul (s,&s,16)) && (*s++ == ':') &&
+				  (s[i] == ':')) {
+				if (sl) sl = sl->next = mail_newstringlist();
+				else sl = sc->references;
+				s[i] = '\0';
+				sl->text.data = cpystr (s);
+				sl->text.size = i;
+			      }
+			      else s = NIL;
+			    }
+			    if (!s || *s ||
+				(s != ((char *) LOCAL->buf + reflen - 1))) {
+			      msg = "references length consistency check";
+			      break;
+			    }
+			  }
+			}
+		      }
+
+				/* UID not found, ignore this message */
+		      else fseek (srtcf,((fromlen ? fromlen + 2 : 0) +
+					 (tolen ? tolen + 2 : 0) +
+					 (cclen ? cclen + 2 : 0) +
+					 (subjlen ? subjlen + 2 : 0) +
+					 (msgidlen ? msgidlen + 2 : 0) +
+					 (reflen ? reflen + 2 : 0)),
+				  SEEK_CUR);
+		      continue;
+		    }
+		    else msg = "expansion";
+		  }
+		  else msg = "references";
+		}
+		else msg = "message-id";
+	      }
+	      else msg = "subject";
+	    }
+	    else msg = "cc";
+	  }
+	  else msg = "to";
+	}
+	else msg = "from";
+      }
+      else msg = "sentdate";
+      break;			/* error somewhere */
+    }
+    if (!t || *t) {		/* error detected? */
+      if (t) {			/* non-null means bogus record */
+	sprintf (tmp,"Error in %s in mix sortcache record: %.500s",msg,t);
+	MM_LOG (tmp,WARN);
+      }
+      fclose (srtcf);		/* either way, must punt */
+      srtcf = NIL;
+    }
+  }
+  if (rdonly && srtcf) {	/* can't update if readonly */
+    unlink (LOCAL->sortcache);	/* try deleting it */
+    fclose (srtcf);		/* so close it and return as if error */
+    srtcf = NIL;
+  }
+  else fchmod (fd,sbuf.st_mode);
+  return srtcf;
+}
+
+/* MIX update and close sortcache
+ * Accepts: MAIL stream
+ *	    pointer to open FILE (if FILE is NIL, do nothing)
+ * Returns: T on success, NIL on error
+ */
+
+long mix_sortcache_update (MAILSTREAM *stream,FILE **sortcache)
+{
+  FILE *f = *sortcache;
+  long ret = LONGT;
+  if (f) {			/* ignore if no file */
+    unsigned long i,j;
+    mailcache_t mc = (mailcache_t) mail_parameters (NIL,GET_CACHE,NIL);
+    for (i = 1; (i <= stream->nmsgs) &&
+	   !((SORTCACHE *) (*mc) (stream,i,CH_SORTCACHE))->dirty; ++i);
+    if (i <= stream->nmsgs) {	/* only update if some entry is dirty */
+      rewind (f);		/* let's start at the very beginning */
+				/* write sequence */
+      fprintf (f,SEQFMT,LOCAL->sortcacheseq = mix_modseq(LOCAL->sortcacheseq));
+      for (i = 1; ret && (i <= stream->nmsgs); ++i) {
+	MESSAGECACHE *elt = mail_elt (stream,i);
+	SORTCACHE *s = (SORTCACHE *) (*mc) (stream,i,CH_SORTCACHE);
+	STRINGLIST *sl;
+	s->dirty = NIL;		/* no longer dirty */
+	if (sl = s->references)	/* count length of references */
+	  for (j = 1; sl && sl->text.data; sl = sl->next)
+	    j += 10 + sl->text.size;
+	else j = 0;		/* no references yet */
+	fprintf (f,SCRFMT,elt->private.uid,s->date,
+		 s->from ? strlen (s->from) + 1 : 0,
+		 s->to ? strlen (s->to) + 1 : 0,s->cc ? strlen (s->cc) + 1 : 0,
+		 s->refwd ? 'R' : ' ',s->subject ? strlen (s->subject) + 1: 0,
+		 s->message_id ? strlen (s->message_id) + 1 : 0,j);
+	if (s->from) fprintf (f,"F%s\015\012",s->from);
+	if (s->to) fprintf (f,"T%s\015\012",s->to);
+	if (s->cc) fprintf (f,"C%s\015\012",s->cc);
+	if (s->subject) fprintf (f,"S%s\015\012",s->subject);
+	if (s->message_id) fprintf (f,"M%s\015\012",s->message_id);
+	if (j) {		/* any references to write? */
+	  fputc ('R',f);	/* yes, do so */
+	  for (sl = s->references; sl && sl->text.data; sl = sl->next)
+	    fprintf (f,"%08lx:%s:",sl->text.size,sl->text.data);
+	  fputs ("\015\012",f);
+	}
+	if (ferror (f)) {
+	  MM_LOG ("Error updating mix sortcache file",WARN);
+	  ret = NIL;
+	}
+      }
+      if (ret && fflush (f)) {
+	MM_LOG ("Error flushing mix sortcache file",WARN);
+	ret = NIL;
+      }
+      if (ret) ftruncate (fileno (f),ftell (f));
+    }
+    if (fclose (f)) {
+      MM_LOG ("Error closing mix sortcache file",WARN);
+      ret = NIL;
+    }
+  }
+  return ret;
+}
+
+/* MIX generic file routines */
+
+/* MIX read record
+ * Accepts: open FILE
+ *	    buffer
+ *	    buffer length
+ *	    record type
+ * Returns: buffer if success, else NIL (zero-length buffer means EOF)
+ */
+
+char *mix_read_record (FILE *f,char *buf,unsigned long buflen,char *type)
+{
+  char *s,tmp[MAILTMPLEN];
+				/* ensure string tied off */
+  buf[buflen-2] = buf[buflen-1] = '\0';
+  while (fgets (buf,buflen-1,f)) {
+    if (s = strchr (buf,'\012')) {
+      if ((s != buf) && (s[-1] == '\015')) --s;
+      *s = '\0';		/* tie off buffer */
+      if (s != buf) return buf;	/* return if non-empty buffer */
+      sprintf (tmp,"Empty mix %s record",type);
+      MM_LOG (tmp,WARN);
+    }
+    else if (buf[buflen-2]) {	/* overlong record is bad news */
+      sprintf (tmp,"Oversize mix %s record: %.512s",type,buf);
+      MM_LOG (tmp,ERROR);
+      return NIL;
+    }
+    else {
+      sprintf (tmp,"Truncated mix %s record: %.512s",type,buf);
+      MM_LOG (tmp,WARN);
+      return buf;		/* pass to caller anyway */
+    }
+  }
+  buf[0] = '\0';		/* return empty buffer on EOF */
+  return buf;
+}
+
+/* MIX read sequence record
+ * Accepts: open FILE
+ * Returns: sequence value, or NIL if failure
+ */
+
+unsigned long mix_read_sequence (FILE *f)
+{
+  unsigned long ret;
+  char *s,tmp[MAILTMPLEN];
+  if (!mix_read_record (f,tmp,MAILTMPLEN-1,"sequence")) return NIL;
+  switch (tmp[0]) {		/* examine record */
+  case '\0':			/* end of file */
+    ret = 1;			/* start a new sequence regime */
+    break;
+  case 'S':			/* sequence record */
+    if (isxdigit (tmp[1])) {	/* must be followed by hex value */
+      ret = strtoul (tmp+1,&s,16);
+      if (!*s) break;		/* and nothing more */
+    }
+				/* drop into default case */
+  default:			/* anything else is an error */
+    return NIL;			/* return error */
+  }
+  return ret;
+}
+
+/* MIX internal routines */
+
+
+/* MIX mail build directory name
+ * Accepts: destination string
+ *          source
+ * Returns: destination or empty string if error
+ */
+
+char *mix_dir (char *dst,char *name)
+{
+  char *s;
+				/* empty string if mailboxfile fails */
+  if (!mailboxfile (dst,name)) *dst = '\0';
+				/* driver-selected INBOX  */
+  else if (!*dst) mailboxfile (dst,"~/INBOX");
+				/* tie off unnecessary trailing / */
+  else if ((s = strrchr (dst,'/')) && !s[1]) *s = '\0';
+  return dst;
+}
+
+
+/* MIX mail build file name
+ * Accepts: destination string
+ *	    directory name
+ *	    file name
+ * Returns: destination
+ */
+
+char *mix_file (char *dst,char *dir,char *name)
+{
+  sprintf (dst,"%.500s/%.80s%.80s",dir,MIXNAME,name);
+  return dst;
+}
+
+
+/* MIX mail build file name from data file number
+ * Accepts: destination string
+ *	    directory name
+ *	    data file number
+ * Returns: destination
+ */
+
+char *mix_file_data (char *dst,char *dir,unsigned long data)
+{
+  char tmp[MAILTMPLEN];
+  if (data) sprintf (tmp,"%08lx",data);
+  else tmp[0] = '\0';		/* compatibility with experimental version */
+  return mix_file (dst,dir,tmp);
+}
+
+/* MIX mail get new modseq
+ * Accepts: old modseq
+ * Returns: new modseq value
+ */
+
+unsigned long mix_modseq (unsigned long oldseq)
+{
+				/* normally time now */
+  unsigned long ret = (unsigned long) time (NIL);
+				/* ensure that modseq doesn't go backwards */
+  if (ret <= oldseq) ret = oldseq + 1;
+  return ret;
+}