--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/osdep/os2/tenexnt.c	Mon Sep 14 15:17:45 2009 +0900
@@ -0,0 +1,1310 @@
+/* ========================================================================
+ * Copyright 1988-2007 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:	Tenex mail routines
+ *
+ * Author:	Mark Crispin
+ *		Networks and Distributed Computing
+ *		Computing & Communications
+ *		University of Washington
+ *		Administration Building, AG-44
+ *		Seattle, WA  98195
+ *		Internet: MRC@CAC.Washington.EDU
+ *
+ * Date:	22 May 1990
+ * Last Edited:	18 June 2007
+ */
+
+
+/*				FILE TIME SEMANTICS
+ *
+ * The atime is the last read time of the file.
+ * The mtime is the last flags update time of the file.
+ * The ctime is the last write time of the file.
+ *
+ *				TEXT SIZE SEMANTICS
+ *
+ * Most of the text sizes are in internal (LF-only) form, except for the
+ * msg.text size.  Beware.
+ */
+
+#include <stdio.h>
+#include <ctype.h>
+#include <errno.h>
+extern int errno;		/* just in case */
+#include "mail.h"
+#include "osdep.h"
+#include <fcntl.h>
+#include <time.h>
+#include <sys/stat.h>
+#include <sys/utime.h>
+#include "misc.h"
+#include "dummy.h"
+
+/* TENEX I/O stream local data */
+	
+typedef struct tenex_local {
+  unsigned int shouldcheck: 1;	/* if ping should do a check instead */
+  unsigned int mustcheck: 1;	/* if ping must do a check instead */
+  int fd;			/* file descriptor for I/O */
+  off_t filesize;		/* file size parsed */
+  time_t filetime;		/* last file time */
+  time_t lastsnarf;		/* local snarf time */
+  unsigned char *buf;		/* temporary buffer */
+  unsigned long buflen;		/* current size of temporary buffer */
+  unsigned long uid;		/* current text uid */
+  SIZEDTEXT text;		/* current text */
+} TENEXLOCAL;
+
+
+/* Convenient access to local data */
+
+#define LOCAL ((TENEXLOCAL *) stream->local)
+
+
+/* Function prototypes */
+
+DRIVER *tenex_valid (char *name);
+int tenex_isvalid (char *name,char *file);
+void *tenex_parameters (long function,void *value);
+void tenex_scan (MAILSTREAM *stream,char *ref,char *pat,char *contents);
+void tenex_list (MAILSTREAM *stream,char *ref,char *pat);
+void tenex_lsub (MAILSTREAM *stream,char *ref,char *pat);
+long tenex_create (MAILSTREAM *stream,char *mailbox);
+long tenex_delete (MAILSTREAM *stream,char *mailbox);
+long tenex_rename (MAILSTREAM *stream,char *old,char *newname);
+long tenex_status (MAILSTREAM *stream,char *mbx,long flags);
+MAILSTREAM *tenex_open (MAILSTREAM *stream);
+void tenex_close (MAILSTREAM *stream,long options);
+void tenex_fast (MAILSTREAM *stream,char *sequence,long flags);
+void tenex_flags (MAILSTREAM *stream,char *sequence,long flags);
+char *tenex_header (MAILSTREAM *stream,unsigned long msgno,
+		    unsigned long *length,long flags);
+long tenex_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags);
+void tenex_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags);
+void tenex_flagmsg (MAILSTREAM *stream,MESSAGECACHE *elt);
+long tenex_ping (MAILSTREAM *stream);
+void tenex_check (MAILSTREAM *stream);
+void tenex_snarf (MAILSTREAM *stream);
+long tenex_expunge (MAILSTREAM *stream,char *sequence,long options);
+long tenex_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options);
+long tenex_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data);
+
+unsigned long tenex_size (MAILSTREAM *stream,unsigned long m);
+long tenex_parse (MAILSTREAM *stream);
+MESSAGECACHE *tenex_elt (MAILSTREAM *stream,unsigned long msgno);
+void tenex_read_flags (MAILSTREAM *stream,MESSAGECACHE *elt);
+void tenex_update_status (MAILSTREAM *stream,unsigned long msgno,
+			  long syncflag);
+unsigned long tenex_hdrpos (MAILSTREAM *stream,unsigned long msgno,
+			    unsigned long *size);
+
+
+/* Tenex mail routines */
+
+
+/* Driver dispatch used by MAIL */
+
+DRIVER tenexdriver = {
+  "tenex",			/* driver name */
+  DR_LOCAL|DR_MAIL,		/* driver flags */
+  (DRIVER *) NIL,		/* next driver */
+  tenex_valid,			/* mailbox is valid for us */
+  tenex_parameters,		/* manipulate parameters */
+  tenex_scan,			/* scan mailboxes */
+  tenex_list,			/* list mailboxes */
+  tenex_lsub,			/* list subscribed mailboxes */
+  NIL,				/* subscribe to mailbox */
+  NIL,				/* unsubscribe from mailbox */
+  tenex_create,			/* create mailbox */
+  tenex_delete,			/* delete mailbox */
+  tenex_rename,			/* rename mailbox */
+  mail_status_default,		/* status of mailbox */
+  tenex_open,			/* open mailbox */
+  tenex_close,			/* close mailbox */
+  tenex_flags,			/* fetch message "fast" attributes */
+  tenex_flags,			/* fetch message flags */
+  NIL,				/* fetch overview */
+  NIL,				/* fetch message envelopes */
+  tenex_header,			/* fetch message header */
+  tenex_text,			/* fetch message body */
+  NIL,				/* fetch partial message text */
+  NIL,				/* unique identifier */
+  NIL,				/* message number */
+  tenex_flag,			/* modify flags */
+  tenex_flagmsg,		/* per-message modify flags */
+  NIL,				/* search for message based on criteria */
+  NIL,				/* sort messages */
+  NIL,				/* thread messages */
+  tenex_ping,			/* ping mailbox to see if still alive */
+  tenex_check,			/* check for new messages */
+  tenex_expunge,		/* expunge deleted messages */
+  tenex_copy,			/* copy messages to another mailbox */
+  tenex_append,			/* append string message to mailbox */
+  NIL				/* garbage collect stream */
+};
+
+				/* prototype stream */
+MAILSTREAM tenexproto = {&tenexdriver};
+
+/* Tenex mail validate mailbox
+ * Accepts: mailbox name
+ * Returns: our driver if name is valid, NIL otherwise
+ */
+
+DRIVER *tenex_valid (char *name)
+{
+  char tmp[MAILTMPLEN];
+  return tenex_isvalid (name,tmp) ? &tenexdriver : NIL;
+}
+
+
+/* Tenex mail test for valid mailbox
+ * Accepts: mailbox name
+ *	    buffer to return file name
+ * Returns: T if valid, NIL otherwise
+ */
+
+int tenex_isvalid (char *name,char *file)
+{
+  int fd;
+  int ret = NIL;
+  char *s,tmp[MAILTMPLEN];
+  struct stat sbuf;
+  struct utimbuf times;
+  errno = EINVAL;		/* assume invalid argument */
+				/* if file, get its status */
+  if ((s = dummy_file (file,name)) && !stat (s,&sbuf) &&
+      ((sbuf.st_mode & S_IFMT) == S_IFREG)) {
+    if (!sbuf.st_size)errno = 0;/* empty file */
+    else if ((fd = open (file,O_BINARY|O_RDONLY,NIL)) >= 0) {
+      memset (tmp,'\0',MAILTMPLEN);
+      if ((read (fd,tmp,64) >= 0) && (s = strchr (tmp,'\012')) &&
+	  (s[-1] != '\015')) {	/* valid format? */
+	*s = '\0';		/* tie off header */
+				/* must begin with dd-mmm-yy" */
+	ret = (((tmp[2] == '-' && tmp[6] == '-') ||
+		(tmp[1] == '-' && tmp[5] == '-')) &&
+	       (s = strchr (tmp+18,',')) && strchr (s+2,';')) ? T : NIL;
+      }
+      else errno = -1;		/* bogus format */
+      close (fd);		/* close the file */
+				/* \Marked status? */
+      if (sbuf.st_ctime > sbuf.st_atime) {
+				/* preserve atime and mtime */
+	times.actime = sbuf.st_atime;
+	times.modtime = sbuf.st_mtime;
+	utime (file,&times);	/* set the times */
+      }
+    }
+  }
+				/* in case INBOX but not tenex format */
+  else if ((errno == ENOENT) && !compare_cstring (name,"INBOX")) errno = -1;
+  return ret;			/* return what we should */
+}
+
+
+/* Tenex manipulate driver parameters
+ * Accepts: function code
+ *	    function-dependent value
+ * Returns: function-dependent return value
+ */
+
+void *tenex_parameters (long function,void *value)
+{
+  return NIL;
+}
+
+/* Tenex mail scan mailboxes
+ * Accepts: mail stream
+ *	    reference
+ *	    pattern to search
+ *	    string to scan
+ */
+
+void tenex_scan (MAILSTREAM *stream,char *ref,char *pat,char *contents)
+{
+  if (stream) dummy_scan (NIL,ref,pat,contents);
+}
+
+
+/* Tenex mail list mailboxes
+ * Accepts: mail stream
+ *	    reference
+ *	    pattern to search
+ */
+
+void tenex_list (MAILSTREAM *stream,char *ref,char *pat)
+{
+  if (stream) dummy_list (NIL,ref,pat);
+}
+
+
+/* Tenex mail list subscribed mailboxes
+ * Accepts: mail stream
+ *	    reference
+ *	    pattern to search
+ */
+
+void tenex_lsub (MAILSTREAM *stream,char *ref,char *pat)
+{
+  if (stream) dummy_lsub (NIL,ref,pat);
+}
+
+/* Tenex mail create mailbox
+ * Accepts: MAIL stream
+ *	    mailbox name to create
+ * Returns: T on success, NIL on failure
+ */
+
+long tenex_create (MAILSTREAM *stream,char *mailbox)
+{
+  char *s,mbx[MAILTMPLEN];
+  if (s = dummy_file (mbx,mailbox)) return dummy_create (stream,s);
+  sprintf (mbx,"Can't create %.80s: invalid name",mailbox);
+  mm_log (mbx,ERROR);
+  return NIL;
+}
+
+
+/* Tenex mail delete mailbox
+ * Accepts: MAIL stream
+ *	    mailbox name to delete
+ * Returns: T on success, NIL on failure
+ */
+
+long tenex_delete (MAILSTREAM *stream,char *mailbox)
+{
+  return tenex_rename (stream,mailbox,NIL);
+}
+
+/* Tenex mail rename mailbox
+ * Accepts: MAIL stream
+ *	    old mailbox name
+ *	    new mailbox name (or NIL for delete)
+ * Returns: T on success, NIL on failure
+ */
+
+long tenex_rename (MAILSTREAM *stream,char *old,char *newname)
+{
+  long ret = LONGT;
+  char c,*s,tmp[MAILTMPLEN],file[MAILTMPLEN],lock[MAILTMPLEN];
+  int fd,ld;
+  struct stat sbuf;
+  if (!dummy_file (file,old) ||
+      (newname && (!((s = mailboxfile (tmp,newname)) && *s) ||
+		   ((s = strrchr (tmp,'\\')) && !s[1])))) {
+    sprintf (tmp,newname ?
+	     "Can't rename mailbox %.80s to %.80s: invalid name" :
+	     "Can't delete mailbox %.80s: invalid name",
+	     old,newname);
+    mm_log (tmp,ERROR);
+    return NIL;
+  }
+  else if ((fd = open (file,O_BINARY|O_RDWR,NIL)) < 0) {
+    sprintf (tmp,"Can't open mailbox %.80s: %s",old,strerror (errno));
+    mm_log (tmp,ERROR);
+    return NIL;
+  }
+				/* get exclusive parse/append permission */
+  if ((ld = lockname (lock,file,LOCK_EX)) < 0) {
+    mm_log ("Unable to lock rename mailbox",ERROR);
+    return NIL;
+  }
+				/* lock out other users */
+  if (flock (fd,LOCK_EX|LOCK_NB)) {
+    close (fd);			/* couldn't lock, give up on it then */
+    sprintf (tmp,"Mailbox %.80s is in use by another process",old);
+    mm_log (tmp,ERROR);
+    unlockfd (ld,lock);		/* release exclusive parse/append permission */
+    return NIL;
+  }
+
+  if (newname) {		/* want rename? */
+				/* found superior to destination name? */
+    if ((s = strrchr (tmp,'\\')) && (s != tmp) &&
+	((tmp[1] != ':') || (s != tmp + 2))) {
+      c = s[1];			/* remember character after delimiter */
+      *s = s[1] = '\0';		/* tie off name at delimiter */
+				/* name doesn't exist, create it */
+      if (stat (tmp,&sbuf) || ((sbuf.st_mode & S_IFMT) != S_IFDIR)) {
+	*s = '\\';		/* restore delimiter */
+	if (!dummy_create (stream,tmp)) ret = NIL;
+      }
+      else *s = '\\';		/* restore delimiter */
+      s[1] = c;			/* restore character after delimiter */
+    }
+    flock (fd,LOCK_UN);		/* release lock on the file */
+    close (fd);			/* pacify NTFS */
+				/* rename the file */
+    if (ret && rename (file,tmp)) {
+      sprintf (tmp,"Can't rename mailbox %.80s to %.80s: %s",old,newname,
+	       strerror (errno));
+      mm_log (tmp,ERROR);
+      ret = NIL;		/* set failure */
+    }
+  }
+  else {
+    flock (fd,LOCK_UN);		/* release lock on the file */
+    close (fd);			/* pacify NTFS */
+    if (unlink (file)) {
+      sprintf (tmp,"Can't delete mailbox %.80s: %.80s",old,strerror (errno));
+      mm_log (tmp,ERROR);
+      ret = NIL;		/* set failure */
+    }
+  }
+  unlockfd (ld,lock);		/* release exclusive parse/append permission */
+  return ret;			/* return success */
+}
+
+/* Tenex mail open
+ * Accepts: stream to open
+ * Returns: stream on success, NIL on failure
+ */
+
+MAILSTREAM *tenex_open (MAILSTREAM *stream)
+{
+  int fd,ld;
+  char tmp[MAILTMPLEN];
+				/* return prototype for OP_PROTOTYPE call */
+  if (!stream) return &tenexproto;
+  if (stream->local) fatal ("tenex recycle stream");
+				/* canonicalize the mailbox name */
+  if (!dummy_file (tmp,stream->mailbox)) {
+    sprintf (tmp,"Can't open - invalid name: %.80s",stream->mailbox);
+    mm_log (tmp,ERROR);
+  }
+  if (stream->rdonly ||
+      (fd = open (tmp,O_BINARY|O_RDWR,NIL)) < 0) {
+    if ((fd = open (tmp,O_BINARY|O_RDONLY,NIL)) < 0) {
+      sprintf (tmp,"Can't open mailbox: %.80s",strerror (errno));
+      mm_log (tmp,ERROR);
+      return NIL;
+    }
+    else if (!stream->rdonly) {	/* got it, but readonly */
+      mm_log ("Can't get write access to mailbox, access is readonly",WARN);
+      stream->rdonly = T;
+    }
+  }
+  stream->local = fs_get (sizeof (TENEXLOCAL));
+  LOCAL->fd = fd;		/* bind the file */
+  LOCAL->buf = (char *) fs_get (CHUNKSIZE);
+  LOCAL->buflen = CHUNKSIZE - 1;
+  LOCAL->text.data = (unsigned char *) fs_get (CHUNKSIZE);
+  LOCAL->text.size = CHUNKSIZE - 1;
+				/* note if an INBOX or not */
+  stream->inbox = !compare_cstring (stream->mailbox,"INBOX");
+  fs_give ((void **) &stream->mailbox);
+  stream->mailbox = cpystr (tmp);
+				/* get shared parse permission */
+  if ((ld = lockname (tmp,stream->mailbox,LOCK_SH)) < 0) {
+    mm_log ("Unable to lock open mailbox",ERROR);
+    return NIL;
+  }
+  flock (LOCAL->fd,LOCK_SH);	/* lock the file */
+  unlockfd (ld,tmp);		/* release shared parse permission */
+  LOCAL->filesize = 0;		/* initialize parsed file size */
+  LOCAL->filetime = 0;		/* time not set up yet */
+  LOCAL->mustcheck = LOCAL->shouldcheck = NIL;
+  stream->sequence++;		/* bump sequence number */
+  stream->uid_validity = (unsigned long) time (0);
+				/* parse mailbox */
+  stream->nmsgs = stream->recent = 0;
+  if (tenex_ping (stream) && !stream->nmsgs)
+    mm_log ("Mailbox is empty",(long) NIL);
+  if (!LOCAL) return NIL;	/* failure if stream died */
+  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;
+  return stream;		/* return stream to caller */
+}
+
+/* Tenex mail close
+ * Accepts: MAIL stream
+ *	    close options
+ */
+
+void tenex_close (MAILSTREAM *stream,long options)
+{
+  if (stream && LOCAL) {	/* only if a file is open */
+    int silent = stream->silent;
+    stream->silent = T;		/* note this stream is dying */
+    if (options & CL_EXPUNGE) tenex_expunge (stream,NIL,NIL);
+    stream->silent = silent;	/* restore previous status */
+    flock (LOCAL->fd,LOCK_UN);	/* unlock local file */
+    close (LOCAL->fd);		/* close the local file */
+				/* free local text buffer */
+    if (LOCAL->buf) fs_give ((void **) &LOCAL->buf);
+    if (LOCAL->text.data) fs_give ((void **) &LOCAL->text.data);
+				/* nuke the local data */
+    fs_give ((void **) &stream->local);
+    stream->dtb = NIL;		/* log out the DTB */
+  }
+}
+
+/* Tenex mail fetch flags
+ * Accepts: MAIL stream
+ *	    sequence
+ *	    option flags
+ * Sniffs at file to get flags
+ */
+
+void tenex_flags (MAILSTREAM *stream,char *sequence,long flags)
+{
+  STRING bs;
+  MESSAGECACHE *elt;
+  unsigned long i;
+  if (stream && LOCAL &&
+      ((flags & FT_UID) ? mail_uid_sequence (stream,sequence) :
+       mail_sequence (stream,sequence)))
+    for (i = 1; i <= stream->nmsgs; i++)
+      if ((elt = mail_elt (stream,i))->sequence) {
+	if (!elt->rfc822_size) { /* have header size yet? */
+	  lseek (LOCAL->fd,elt->private.special.offset +
+		 elt->private.special.text.size,L_SET);
+				/* resize bigbuf if necessary */
+	  if (LOCAL->buflen < elt->private.msg.full.text.size) {
+	    fs_give ((void **) &LOCAL->buf);
+	    LOCAL->buflen = elt->private.msg.full.text.size;
+	    LOCAL->buf = (char *) fs_get (LOCAL->buflen + 1);
+	  }
+				/* tie off string */
+	  LOCAL->buf[elt->private.msg.full.text.size] = '\0';
+				/* read in the message */
+	  read (LOCAL->fd,LOCAL->buf,elt->private.msg.full.text.size);
+	  INIT (&bs,mail_string,(void *) LOCAL->buf,
+		elt->private.msg.full.text.size);
+				/* calculate its CRLF size */
+	  elt->rfc822_size = unix_crlflen (&bs);
+	}
+	tenex_elt (stream,i);	/* get current flags from file */
+      }
+}
+
+/* TENEX 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 *tenex_header (MAILSTREAM *stream,unsigned long msgno,
+		    unsigned long *length,long flags)
+{
+  char *s;
+  unsigned long i;
+  *length = 0;			/* default to empty */
+  if (flags & FT_UID) return "";/* UID call "impossible" */
+				/* get to header position */
+  lseek (LOCAL->fd,tenex_hdrpos (stream,msgno,&i),L_SET);
+  if (flags & FT_INTERNAL) {
+    if (i > LOCAL->buflen) {	/* resize if not enough space */
+      fs_give ((void **) &LOCAL->buf);
+      LOCAL->buf = (char *) fs_get (LOCAL->buflen = i + 1);
+    }
+				/* slurp the data */
+    read (LOCAL->fd,LOCAL->buf,*length = i);
+  }
+  else {
+    s = (char *) fs_get (i + 1);/* get readin buffer */
+    s[i] = '\0';		/* tie off string */
+    read (LOCAL->fd,s,i);	/* slurp the data */
+				/* make CRLF copy of string */
+    *length = unix_crlfcpy (&LOCAL->buf,&LOCAL->buflen,s,i);
+    fs_give ((void **) &s);	/* free readin buffer */
+  }
+  return LOCAL->buf;
+}
+
+/* TENEX mail fetch message text (body only)
+ * Accepts: MAIL stream
+ *	    message # to fetch
+ *	    pointer to returned stringstruct
+ *	    option flags
+ * Returns: T, always
+ */
+
+long tenex_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags)
+{
+  char *s;
+  unsigned long i,j;
+  MESSAGECACHE *elt;
+				/* UID call "impossible" */
+  if (flags & FT_UID) return NIL;
+				/* get message status */
+  elt = tenex_elt (stream,msgno);
+				/* if message not seen */
+  if (!(flags & FT_PEEK) && !elt->seen) {
+    elt->seen = T;		/* mark message as seen */
+				/* recalculate status */
+    tenex_update_status (stream,msgno,T);
+    mm_flags (stream,msgno);
+  }
+  if (flags & FT_INTERNAL) {	/* if internal representation wanted */
+				/* find header position */
+    i = tenex_hdrpos (stream,msgno,&j);
+    if (i > LOCAL->buflen) {	/* resize if not enough space */
+      fs_give ((void **) &LOCAL->buf);
+      LOCAL->buf = (char *) fs_get (LOCAL->buflen = i + 1);
+    }
+				/* go to text position */
+    lseek (LOCAL->fd,i + j,L_SET);
+				/* slurp the data */
+    if (read (LOCAL->fd,LOCAL->buf,i) != (long) i) return NIL;
+				/* set up stringstruct for internal */
+    INIT (bs,mail_string,LOCAL->buf,i);
+  }
+  else {			/* normal form, previous text cached? */
+    if (elt->private.uid == LOCAL->uid)
+      i = elt->private.msg.text.text.size;
+    else {			/* not cached, cache it now */
+      LOCAL->uid = elt->private.uid;
+				/* find header position */
+      i = tenex_hdrpos (stream,msgno,&j);
+				/* go to text position */
+      lseek (LOCAL->fd,i + j,L_SET);
+      s = (char *) fs_get ((i = tenex_size (stream,msgno) - j) + 1);
+      s[i] = '\0';		/* tie off string */
+      read (LOCAL->fd,s,i);	/* slurp the data */
+				/* make CRLF copy of string */
+      i = elt->private.msg.text.text.size =
+	strcrlfcpy (&LOCAL->text.data,&LOCAL->text.size,s,i);
+      fs_give ((void **) &s);	/* free readin buffer */
+    }
+				/* set up stringstruct */
+    INIT (bs,mail_string,LOCAL->text.data,i);
+  }
+  return T;			/* success */
+}
+
+/* Tenex mail modify flags
+ * Accepts: MAIL stream
+ *	    sequence
+ *	    flag(s)
+ *	    option flags
+ */
+
+void tenex_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags)
+{
+  struct utimbuf times;
+  struct stat sbuf;
+  if (!stream->rdonly) {	/* make sure the update takes */
+    fsync (LOCAL->fd);
+    fstat (LOCAL->fd,&sbuf);	/* get current write time */
+    times.modtime = LOCAL->filetime = sbuf.st_mtime;
+    times.actime = time (0);	/* make sure read comes after all that */
+    utime (stream->mailbox,&times);
+  }
+}
+
+
+/* Tenex mail per-message modify flags
+ * Accepts: MAIL stream
+ *	    message cache element
+ */
+
+void tenex_flagmsg (MAILSTREAM *stream,MESSAGECACHE *elt)
+{
+  struct stat sbuf;
+				/* maybe need to do a checkpoint? */
+  if (LOCAL->filetime && !LOCAL->shouldcheck) {
+    fstat (LOCAL->fd,&sbuf);	/* get current write time */
+    if (LOCAL->filetime < sbuf.st_mtime) LOCAL->shouldcheck = T;
+    LOCAL->filetime = 0;	/* don't do this test for any other messages */
+  }
+				/* recalculate status */
+  tenex_update_status (stream,elt->msgno,NIL);
+}
+
+/* Tenex mail ping mailbox
+ * Accepts: MAIL stream
+ * Returns: T if stream still alive, NIL if not
+ */
+
+long tenex_ping (MAILSTREAM *stream)
+{
+  unsigned long i = 1;
+  long r = T;
+  int ld;
+  char lock[MAILTMPLEN];
+  struct stat sbuf;
+  if (stream && LOCAL) {	/* only if stream already open */
+    fstat (LOCAL->fd,&sbuf);	/* get current file poop */
+    if (LOCAL->filetime && !(LOCAL->mustcheck || LOCAL->shouldcheck) &&
+	(LOCAL->filetime < sbuf.st_mtime)) LOCAL->shouldcheck = T;
+				/* check for changed message status */
+    if (LOCAL->mustcheck || LOCAL->shouldcheck) {
+      LOCAL->filetime = sbuf.st_mtime;
+      if (LOCAL->shouldcheck)	/* babble when we do this unilaterally */
+	mm_notify (stream,"[CHECK] Checking for flag updates",NIL);
+      while (i <= stream->nmsgs) tenex_elt (stream,i++);
+      LOCAL->mustcheck = LOCAL->shouldcheck = NIL;
+    }
+				/* get shared parse/append permission */
+    if ((sbuf.st_size != LOCAL->filesize) &&
+	((ld = lockname (lock,stream->mailbox,LOCK_SH)) >= 0)) {
+				/* parse resulting mailbox */
+      r = (tenex_parse (stream)) ? T : NIL;
+      unlockfd (ld,lock);	/* release shared parse/append permission */
+    }
+  }
+  return r;			/* return result of the parse */
+}
+
+
+/* Tenex mail check mailbox (reparses status too)
+ * Accepts: MAIL stream
+ */
+
+void tenex_check (MAILSTREAM *stream)
+{
+				/* mark that a check is desired */
+  if (LOCAL) LOCAL->mustcheck = T;
+  if (tenex_ping (stream)) mm_log ("Check completed",(long) NIL);
+}
+
+/* Tenex mail expunge mailbox
+ *	    sequence to expunge if non-NIL
+ *	    expunge options
+ * Returns: T, always
+ */
+
+long tenex_expunge (MAILSTREAM *stream,char *sequence,long options)
+{
+  long ret;
+  struct utimbuf times;
+  struct stat sbuf;
+  off_t pos = 0;
+  int ld;
+  unsigned long i = 1;
+  unsigned long j,k,m,recent;
+  unsigned long n = 0;
+  unsigned long delta = 0;
+  char lock[MAILTMPLEN];
+  MESSAGECACHE *elt;
+  if (!(ret = (sequence ? ((options & EX_UID) ?
+			   mail_uid_sequence (stream,sequence) :
+			   mail_sequence (stream,sequence)) : LONGT) &&
+	tenex_ping (stream)));	/* parse sequence if given, ping stream */
+  else if (stream->rdonly) mm_log ("Expunge ignored on readonly mailbox",WARN);
+  else {
+    if (LOCAL->filetime && !LOCAL->shouldcheck) {
+      fstat (LOCAL->fd,&sbuf);	/* get current write time */
+      if (LOCAL->filetime < sbuf.st_mtime) LOCAL->shouldcheck = T;
+    }
+				/* get exclusive access */
+    if ((ld = lockname (lock,stream->mailbox,LOCK_EX)) < 0)
+      mm_log ("Unable to lock expunge mailbox",ERROR);
+				/* make sure see any newly-arrived messages */
+    else if (!tenex_parse (stream));
+				/* get exclusive access */
+    else if (flock (LOCAL->fd,LOCK_EX|LOCK_NB)) {
+      flock (LOCAL->fd,LOCK_SH);/* recover previous lock */
+      mm_log ("Can't expunge because mailbox is in use by another process",
+	      ERROR);
+      unlockfd (ld,lock);	/* release exclusive parse/append permission */
+    }
+
+    else {
+      mm_critical (stream);	/* go critical */
+      recent = stream->recent;	/* get recent now that pinged and locked */
+				/* for each message */
+      while (i <= stream->nmsgs) {
+				/* get cache element */
+	elt = tenex_elt (stream,i);
+				/* number of bytes to smash or preserve */
+	k = elt->private.special.text.size + tenex_size (stream,i);
+				/* if need to expunge this message */
+	if (elt->deleted && (sequence ? elt->sequence : T)) {
+				/* if recent, note one less recent message */
+	  if (elt->recent) --recent;
+	  delta += k;		/* number of bytes to delete */
+				/* notify upper levels */
+	  mail_expunged (stream,i);
+	  n++;			/* count up one more expunged message */
+	}
+	else if (i++ && delta) {/* preserved message */
+				/* first byte to preserve */
+	  j = elt->private.special.offset;
+	  do {			/* read from source position */
+	    m = min (k,LOCAL->buflen);
+	    lseek (LOCAL->fd,j,L_SET);
+	    read (LOCAL->fd,LOCAL->buf,m);
+	    pos = j - delta;	/* write to destination position */
+	    while (T) {
+	      lseek (LOCAL->fd,pos,L_SET);
+	      if (write (LOCAL->fd,LOCAL->buf,m) > 0) break;
+	      mm_notify (stream,strerror (errno),WARN);
+	      mm_diskerror (stream,errno,T);
+	    }
+	    pos += m;		/* new position */
+	    j += m;		/* next chunk, perhaps */
+	  } while (k -= m);	/* until done */
+				/* note the new address of this text */
+	  elt->private.special.offset -= delta;
+	}
+				/* preserved but no deleted messages */
+	else pos = elt->private.special.offset + k;
+      }
+
+      if (n) {			/* truncate file after last message */
+	if (pos != (LOCAL->filesize -= delta)) {
+	  sprintf (LOCAL->buf,
+		   "Calculated size mismatch %lu != %lu, delta = %lu",
+		   (unsigned long) pos,(unsigned long) LOCAL->filesize,delta);
+	  mm_log (LOCAL->buf,WARN);
+	  LOCAL->filesize = pos;/* fix it then */
+	}
+	ftruncate (LOCAL->fd,LOCAL->filesize);
+	sprintf (LOCAL->buf,"Expunged %lu messages",n);
+				/* output the news */
+	mm_log (LOCAL->buf,(long) NIL);
+      }
+      else mm_log ("No messages deleted, so no update needed",(long) NIL);
+      fsync (LOCAL->fd);	/* force disk update */
+      fstat (LOCAL->fd,&sbuf);	/* get new write time */
+      times.modtime = LOCAL->filetime = sbuf.st_mtime;
+      times.actime = time (0);	/* reset atime to now */
+      utime (stream->mailbox,&times);
+      mm_nocritical (stream);	/* release critical */
+				/* notify upper level of new mailbox size */
+      mail_exists (stream,stream->nmsgs);
+      mail_recent (stream,recent);
+      flock (LOCAL->fd,LOCK_SH);/* allow sharers again */
+      unlockfd (ld,lock);	/* release exclusive parse/append permission */
+    }
+  }
+  return ret;
+}
+
+/* Tenex mail copy message(s)
+ * Accepts: MAIL stream
+ *	    sequence
+ *	    destination mailbox
+ *	    copy options
+ * Returns: T if success, NIL if failed
+ */
+
+long tenex_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options)
+{
+  struct stat sbuf;
+  struct utimbuf times;
+  MESSAGECACHE *elt;
+  unsigned long i,j,k;
+  long ret = LONGT;
+  int fd,ld;
+  char file[MAILTMPLEN],lock[MAILTMPLEN];
+  mailproxycopy_t pc =
+    (mailproxycopy_t) mail_parameters (stream,GET_MAILPROXYCOPY,NIL);
+				/* make sure valid mailbox */
+  if (!tenex_isvalid (mailbox,file)) switch (errno) {
+  case ENOENT:			/* no such file? */
+    mm_notify (stream,"[TRYCREATE] Must create mailbox before copy",NIL);
+    return NIL;
+  case 0:			/* merely empty file? */
+    break;
+  case EACCES:			/* file protected */
+    sprintf (LOCAL->buf,"Can't access destination: %.80s",mailbox);
+    MM_LOG (LOCAL->buf,ERROR);
+    return NIL;
+  case EINVAL:
+    if (pc) return (*pc) (stream,sequence,mailbox,options);
+    sprintf (LOCAL->buf,"Invalid Tenex-format mailbox name: %.80s",mailbox);
+    mm_log (LOCAL->buf,ERROR);
+    return NIL;
+  default:
+    if (pc) return (*pc) (stream,sequence,mailbox,options);
+    sprintf (LOCAL->buf,"Not a Tenex-format mailbox: %.80s",mailbox);
+    mm_log (LOCAL->buf,ERROR);
+    return NIL;
+  }
+  if (!((options & CP_UID) ? mail_uid_sequence (stream,sequence) :
+	mail_sequence (stream,sequence))) return NIL;
+				/* got file? */  
+  if ((fd = open (file,O_BINARY|O_RDWR|O_CREAT,S_IREAD|S_IWRITE)) < 0) {
+    sprintf (LOCAL->buf,"Unable to open copy mailbox: %.80s",strerror (errno));
+    mm_log (LOCAL->buf,ERROR);
+    return NIL;
+  }
+  mm_critical (stream);		/* go critical */
+				/* get exclusive parse/append permission */
+  if (flock (fd,LOCK_SH) || ((ld = lockname (lock,file,LOCK_EX)) < 0)) {
+    mm_log ("Unable to lock copy mailbox",ERROR);
+    mm_nocritical (stream);
+    return NIL;
+  }
+  fstat (fd,&sbuf);		/* get current file size */
+  lseek (fd,sbuf.st_size,L_SET);/* move to end of file */
+
+				/* for each requested message */
+  for (i = 1; ret && (i <= stream->nmsgs); i++) 
+    if ((elt = mail_elt (stream,i))->sequence) {
+      lseek (LOCAL->fd,elt->private.special.offset,L_SET);
+				/* number of bytes to copy */
+      k = elt->private.special.text.size + tenex_size (stream,i);
+      do {			/* read from source position */
+	j = min (k,LOCAL->buflen);
+	read (LOCAL->fd,LOCAL->buf,j);
+	if (write (fd,LOCAL->buf,j) < 0) ret = NIL;
+      } while (ret && (k -= j));/* until done */
+    }
+				/* delete all requested messages */
+  if (ret && (options & CP_MOVE)) {
+    sprintf (LOCAL->buf,"Unable to write message: %s",strerror (errno));
+    mm_log (LOCAL->buf,ERROR);
+    ftruncate (fd,sbuf.st_size);
+  }
+				/* set atime to now-1 if successful copy */
+  if (ret) times.actime = time (0) - 1;
+				/* else preserved \Marked status */
+  else times.actime = (sbuf.st_ctime > sbuf.st_atime) ?
+	 sbuf.st_atime : time (0);
+  times.modtime = sbuf.st_mtime;/* preserve mtime */
+  utime (file,&times);		/* set the times */
+  unlockfd (ld,lock);		/* release exclusive parse/append permission */
+  close (fd);			/* close the file */
+  mm_nocritical (stream);	/* release critical */
+				/* delete all requested messages */
+  if (ret && (options & CP_MOVE)) {
+    for (i = 1; i <= stream->nmsgs; i++)
+      if ((elt = tenex_elt (stream,i))->sequence) {
+	elt->deleted = T;	/* mark message deleted */
+				/* recalculate status */
+	tenex_update_status (stream,i,NIL);
+      }
+    if (!stream->rdonly) {	/* make sure the update takes */
+      fsync (LOCAL->fd);
+      fstat (LOCAL->fd,&sbuf);	/* get current write time */
+      times.modtime = LOCAL->filetime = sbuf.st_mtime;
+      times.actime = time (0);	/* make sure atime remains greater */
+      utime (stream->mailbox,&times);
+    }
+  }
+  if (ret && mail_parameters (NIL,GET_COPYUID,NIL))
+    mm_log ("Can not return meaningful COPYUID with this mailbox format",WARN);
+  return ret;
+}
+
+/* Tenex mail append message from stringstruct
+ * Accepts: MAIL stream
+ *	    destination mailbox
+ *	    append callback
+ *	    data for callback
+ * Returns: T if append successful, else NIL
+ */
+
+long tenex_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data)
+{
+  struct stat sbuf;
+  int fd,ld,c;
+  char *flags,*date,tmp[MAILTMPLEN],file[MAILTMPLEN],lock[MAILTMPLEN];
+  struct utimbuf times;
+  FILE *df;
+  MESSAGECACHE elt;
+  long f;
+  unsigned long i,j,uf,size;
+  STRING *message;
+  long ret = LONGT;
+				/* default stream to prototype */
+  if (!stream) stream = &tenexproto;
+				/* make sure valid mailbox */
+  if (!tenex_isvalid (mailbox,file)) switch (errno) {
+  case ENOENT:			/* no such file? */
+    if (!compare_cstring (mailbox,"INBOX")) tenex_create (NIL,"INBOX");
+    else {
+      mm_notify (stream,"[TRYCREATE] Must create mailbox before append",NIL);
+      return NIL;
+    }
+				/* falls through */
+  case 0:			/* merely empty file? */
+    break;
+  case EACCES:			/* file protected */
+    sprintf (tmp,"Can't access destination: %.80s",mailbox);
+    MM_LOG (tmp,ERROR);
+    return NIL;
+  case EINVAL:
+    sprintf (tmp,"Invalid TENEX-format mailbox name: %.80s",mailbox);
+    mm_log (tmp,ERROR);
+    return NIL;
+  default:
+    sprintf (tmp,"Not a TENEX-format mailbox: %.80s",mailbox);
+    mm_log (tmp,ERROR);
+    return NIL;
+  }
+				/* get first message */
+  if (!(*af) (stream,data,&flags,&date,&message)) return NIL;
+
+				/* open destination mailbox */
+  if (((fd = open (file,O_BINARY|O_WRONLY|O_APPEND|O_CREAT,S_IREAD|S_IWRITE))
+       < 0) || !(df = fdopen (fd,"ab"))) {
+    sprintf (tmp,"Can't open append mailbox: %s",strerror (errno));
+    mm_log (tmp,ERROR);
+    return NIL;
+  }
+				/* get parse/append permission */
+  if (flock (fd,LOCK_SH) || ((ld = lockname (lock,file,LOCK_EX)) < 0)) {
+    mm_log ("Unable to lock append mailbox",ERROR);
+    close (fd);
+    return NIL;
+  }
+  mm_critical (stream);		/* go critical */
+  fstat (fd,&sbuf);		/* get current file size */
+  errno = 0;
+  do {				/* parse flags */
+    if (!SIZE (message)) {	/* guard against zero-length */
+      mm_log ("Append of zero-length message",ERROR);
+      ret = NIL;
+      break;
+    }
+    f = mail_parse_flags (stream,flags,&i);
+				/* reverse bits (dontcha wish we had CIRC?) */
+    for (uf = 0; i; uf |= 1 << (29 - find_rightmost_bit (&i)));
+    if (date) {			/* parse date if given */
+      if (!mail_parse_date (&elt,date)) {
+	sprintf (tmp,"Bad date in append: %.80s",date);
+	mm_log (tmp,ERROR);
+	ret = NIL;		/* mark failure */
+	break;
+      }
+      mail_date (tmp,&elt);	/* write preseved date */
+    }
+    else internal_date (tmp);	/* get current date in IMAP format */
+    i = GETPOS (message);	/* remember current position */
+    for (j = SIZE (message), size = 0; j; --j)
+      if (SNX (message) != '\015') ++size;
+    SETPOS (message,i);		/* restore position */
+				/* write header */
+    if (fprintf (df,"%s,%lu;%010lo%02lo\n",tmp,size,uf,(unsigned long) f) < 0)
+      ret = NIL;
+    else {			/* write message */
+      while (size) if ((c = 0xff & SNX (message)) != '\015') {
+	if (putc (c,df) != EOF) --size;
+	else break;
+      }
+				/* get next message */
+      if (size || !(*af) (stream,data,&flags,&date,&message)) ret = NIL;
+    }
+  } while (ret && message);
+				/* if error... */
+  if (!ret || (fflush (df) == EOF)) {
+    ftruncate (fd,sbuf.st_size);/* revert file */
+    close (fd);			/* make sure fclose() doesn't corrupt us */
+    if (errno) {
+      sprintf (tmp,"Message append failed: %s",strerror (errno));
+      mm_log (tmp,ERROR);
+    }
+    ret = NIL;
+  }
+  if (ret) times.actime = time (0) - 1;
+				/* else preserved \Marked status */
+  else times.actime = (sbuf.st_ctime > sbuf.st_atime) ?
+	 sbuf.st_atime : time (0);
+  times.modtime = sbuf.st_mtime;/* preserve mtime */
+  utime (file,&times);		/* set the times */
+  fclose (df);			/* close the file */
+  unlockfd (ld,lock);		/* release exclusive parse/append permission */
+  mm_nocritical (stream);	/* release critical */
+  if (ret && mail_parameters (NIL,GET_APPENDUID,NIL))
+    mm_log ("Can not return meaningful APPENDUID with this mailbox format",
+	    WARN);
+  return ret;
+}
+
+/* Internal routines */
+
+
+/* Tenex mail return internal message size in bytes
+ * Accepts: MAIL stream
+ *	    message #
+ * Returns: internal size of message
+ */
+
+unsigned long tenex_size (MAILSTREAM *stream,unsigned long m)
+{
+  MESSAGECACHE *elt = mail_elt (stream,m);
+  return ((m < stream->nmsgs) ? mail_elt (stream,m+1)->private.special.offset :
+	  LOCAL->filesize) -
+	    (elt->private.special.offset + elt->private.special.text.size);
+}
+
+/* Tenex mail parse mailbox
+ * Accepts: MAIL stream
+ * Returns: T if parse OK
+ *	    NIL if failure, stream aborted
+ */
+
+long tenex_parse (MAILSTREAM *stream)
+{
+  struct stat sbuf;
+  MESSAGECACHE *elt = NIL;
+  unsigned char c,*s,*t,*x;
+  char tmp[MAILTMPLEN];
+  unsigned long i,j;
+  long curpos = LOCAL->filesize;
+  long nmsgs = stream->nmsgs;
+  long recent = stream->recent;
+  short added = NIL;
+  short silent = stream->silent;
+  fstat (LOCAL->fd,&sbuf);	/* get status */
+  if (sbuf.st_size < curpos) {	/* sanity check */
+    sprintf (tmp,"Mailbox shrank from %ld to %ld!",curpos,sbuf.st_size);
+    mm_log (tmp,ERROR);
+    tenex_close (stream,NIL);
+    return NIL;
+  }
+  stream->silent = T;		/* don't pass up mm_exists() events yet */
+  while (sbuf.st_size - curpos){/* while there is stuff to parse */
+				/* get to that position in the file */
+    lseek (LOCAL->fd,curpos,L_SET);
+    if ((i = read (LOCAL->fd,LOCAL->buf,64)) <= 0) {
+      sprintf (tmp,"Unable to read internal header at %lu, size = %lu: %s",
+	       (unsigned long) curpos,(unsigned long) sbuf.st_size,
+	       i ? strerror (errno) : "no data read");
+      mm_log (tmp,ERROR);
+      tenex_close (stream,NIL);
+      return NIL;
+    }
+    LOCAL->buf[i] = '\0';	/* tie off buffer just in case */
+    if (!(s = strchr (LOCAL->buf,'\012'))) {
+      sprintf (tmp,"Unable to find newline at %lu in %lu bytes, text: %s",
+	       (unsigned long) curpos,i,(char *) LOCAL->buf);
+      mm_log (tmp,ERROR);
+      tenex_close (stream,NIL);
+      return NIL;
+    }
+    *s = '\0';			/* tie off header line */
+    i = (s + 1) - LOCAL->buf;	/* note start of text offset */
+    if (!((s = strchr (LOCAL->buf,',')) && (t = strchr (s+1,';')))) {
+      sprintf (tmp,"Unable to parse internal header at %lu: %s",
+	       (unsigned long) curpos,(char *) LOCAL->buf);
+      mm_log (tmp,ERROR);
+      tenex_close (stream,NIL);
+      return NIL;
+    }
+    *s++ = '\0'; *t++ = '\0';	/* tie off fields */
+
+    added = T;			/* note that a new message was added */
+				/* swell the cache */
+    mail_exists (stream,++nmsgs);
+				/* instantiate an elt for this message */
+    (elt = mail_elt (stream,nmsgs))->valid = T;
+    elt->private.uid = ++stream->uid_last;
+				/* note file offset of header */
+    elt->private.special.offset = curpos;
+				/* in case error */
+    elt->private.special.text.size = 0;
+				/* header size not known yet */
+    elt->private.msg.header.text.size = 0;
+    x = s;			/* parse the header components */
+    if (mail_parse_date (elt,LOCAL->buf) &&
+	(elt->private.msg.full.text.size = strtoul (s,(char **) &s,10)) &&
+	(!(s && *s)) && isdigit (t[0]) && 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]) && !t[12])
+      elt->private.special.text.size = i;
+    else {			/* oops */
+      sprintf (tmp,"Unable to parse internal header elements at %ld: %s,%s;%s",
+	       curpos,(char *) LOCAL->buf,(char *) x,(char *) t);
+      mm_log (tmp,ERROR);
+      tenex_close (stream,NIL);
+      return NIL;
+    }
+				/* make sure didn't run off end of file */
+    if ((curpos += (elt->private.msg.full.text.size + i)) > sbuf.st_size) {
+      sprintf (tmp,"Last message (at %lu) runs past end of file (%lu > %lu)",
+	       elt->private.special.offset,(unsigned long) curpos,
+	       (unsigned long) sbuf.st_size);
+      mm_log (tmp,ERROR);
+      tenex_close (stream,NIL);
+      return NIL;
+    }
+    c = t[10];			/* remember first system flags byte */
+    t[10] = '\0';		/* tie off flags */
+    j = strtoul (t,NIL,8);	/* get user flags value */
+    t[10] = c;			/* restore first system flags byte */
+				/* set up all valid user flags (reversed!) */
+    while (j) if (((i = 29 - find_rightmost_bit (&j)) < NUSERFLAGS) &&
+		  stream->user_flags[i]) elt->user_flags |= 1 << i;
+				/* calculate system flags */
+    if ((j = ((t[10]-'0') * 8) + t[11]-'0') & fSEEN) elt->seen = T;
+    if (j & fDELETED) elt->deleted = T;
+    if (j & fFLAGGED) elt->flagged = T;
+    if (j & fANSWERED) elt->answered = T;
+    if (j & fDRAFT) elt->draft = T;
+    if (!(j & fOLD)) {		/* newly arrived message? */
+      elt->recent = T;
+      recent++;			/* count up a new recent message */
+				/* mark it as old */
+      tenex_update_status (stream,nmsgs,NIL);
+    }
+  }
+  fsync (LOCAL->fd);		/* make sure all the fOLD flags take */
+				/* update parsed file size and time */
+  LOCAL->filesize = sbuf.st_size;
+  fstat (LOCAL->fd,&sbuf);	/* get status again to ensure time is right */
+  LOCAL->filetime = sbuf.st_mtime;
+  if (added && !stream->rdonly){/* make sure atime updated */
+    struct utimbuf times;
+    times.actime = time (0);
+    times.modtime = LOCAL->filetime;
+    utime (stream->mailbox,&times);
+  }
+  stream->silent = silent;	/* can pass up events now */
+  mail_exists (stream,nmsgs);	/* notify upper level of new mailbox size */
+  mail_recent (stream,recent);	/* and of change in recent messages */
+  return LONGT;			/* return the winnage */
+}
+
+/* Tenex get cache element with status updating from file
+ * Accepts: MAIL stream
+ *	    message number
+ * Returns: cache element
+ */
+
+MESSAGECACHE *tenex_elt (MAILSTREAM *stream,unsigned long msgno)
+{
+  MESSAGECACHE *elt = mail_elt (stream,msgno);
+  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;
+  tenex_read_flags (stream,elt);
+  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))
+    mm_flags (stream,msgno);	/* let top level know */
+  return elt;
+}
+
+
+/* Tenex read flags from file
+ * Accepts: MAIL stream
+ * Returns: cache element
+ */
+
+void tenex_read_flags (MAILSTREAM *stream,MESSAGECACHE *elt)
+{
+  unsigned long i,j;
+				/* noop if readonly and have valid flags */
+  if (stream->rdonly && elt->valid) return;
+				/* set the seek pointer */
+  lseek (LOCAL->fd,(off_t) elt->private.special.offset +
+	 elt->private.special.text.size - 13,L_SET);
+				/* read the new flags */
+  if (read (LOCAL->fd,LOCAL->buf,12) < 0) {
+    sprintf (LOCAL->buf,"Unable to read new status: %s",strerror (errno));
+    fatal (LOCAL->buf);
+  }
+				/* calculate system flags */
+  i = (((LOCAL->buf[10]-'0') * 8) + LOCAL->buf[11]-'0');
+  elt->seen = i & fSEEN ? T : NIL; elt->deleted = i & fDELETED ? T : NIL;
+  elt->flagged = i & fFLAGGED ? T : NIL;
+  elt->answered = i & fANSWERED ? T : NIL; elt->draft = i & fDRAFT ? T : NIL;
+  LOCAL->buf[10] = '\0';	/* tie off flags */
+  j = strtoul(LOCAL->buf,NIL,8);/* get user flags value */
+				/* set up all valid user flags (reversed!) */
+  while (j) if (((i = 29 - find_rightmost_bit (&j)) < NUSERFLAGS) &&
+		stream->user_flags[i]) elt->user_flags |= 1 << i;
+  elt->valid = T;		/* have valid flags now */
+}
+
+/* Tenex update status string
+ * Accepts: MAIL stream
+ *	    message number
+ *	    flag saying whether or not to sync
+ */
+
+void tenex_update_status (MAILSTREAM *stream,unsigned long msgno,long syncflag)
+{
+  struct utimbuf times;
+  struct stat sbuf;
+  MESSAGECACHE *elt = mail_elt (stream,msgno);
+  unsigned long j,k = 0;
+				/* readonly */
+  if (stream->rdonly || !elt->valid) tenex_read_flags (stream,elt);
+  else {			/* readwrite */
+    j = elt->user_flags;	/* get user flags */
+				/* reverse bits (dontcha wish we had CIRC?) */
+    while (j) k |= 1 << (29 - find_rightmost_bit (&j));
+				/* print new flag string */
+    sprintf (LOCAL->buf,"%010lo%02o",k,(unsigned)
+	     (fOLD + (fSEEN * elt->seen) + (fDELETED * elt->deleted) +
+	      (fFLAGGED * elt->flagged) + (fANSWERED * elt->answered) +
+	      (fDRAFT * elt->draft)));
+    while (T) {			/* get to that place in the file */
+      lseek (LOCAL->fd,(off_t) elt->private.special.offset +
+	     elt->private.special.text.size - 13,L_SET);
+				/* write new flags */
+      if (write (LOCAL->fd,LOCAL->buf,12) > 0) break;
+      mm_notify (stream,strerror (errno),WARN);
+      mm_diskerror (stream,errno,T);
+    }
+    if (syncflag) {		/* sync if requested */
+      fsync (LOCAL->fd);
+      fstat (LOCAL->fd,&sbuf);	/* get new write time */
+      times.modtime = LOCAL->filetime = sbuf.st_mtime;
+      times.actime = time (0);	/* make sure read is later */
+      utime (stream->mailbox,&times);
+    }
+  }
+}
+
+/* Tenex locate header for a message
+ * Accepts: MAIL stream
+ *	    message number
+ *	    pointer to returned header size
+ * Returns: position of header in file
+ */
+
+unsigned long tenex_hdrpos (MAILSTREAM *stream,unsigned long msgno,
+			    unsigned long *size)
+{
+  unsigned long siz;
+  long i = 0;
+  char c = '\0';
+  char *s = NIL;
+  MESSAGECACHE *elt = tenex_elt (stream,msgno);
+  unsigned long ret = elt->private.special.offset +
+    elt->private.special.text.size;
+  unsigned long msiz = tenex_size (stream,msgno);
+				/* is header size known? */
+  if (!(*size = elt->private.msg.header.text.size)) {
+    lseek (LOCAL->fd,ret,L_SET);/* get to header position */
+				/* search message for LF LF */
+    for (siz = 0; siz < msiz; siz++) {
+      if (--i <= 0)		/* read another buffer as necessary */
+	read (LOCAL->fd,s = LOCAL->buf,i = min (msiz-siz,(long) MAILTMPLEN));
+				/* two newline sequence? */
+      if ((c == '\012') && (*s == '\012')) {
+				/* yes, note for later */
+	elt->private.msg.header.text.size = (*size = siz + 1);
+	return ret;		/* return to caller */
+      }
+      else c = *s++;		/* next character */
+    }
+				/* header consumes entire message */
+    elt->private.msg.header.text.size = *size = msiz;
+  }
+  return ret;
+}