/*
 * Program:	MBX 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:	3 October 1995
 * Last Edited:	4 January 1996
 *
 * Copyright 1996 by the University of Washington
 *
 *  Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose and without fee is hereby granted, provided
 * that the above copyright notice appears in all copies and that both the
 * above copyright notice and this permission notice appear in supporting
 * documentation, and that the name of the University of Washington not be
 * used in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission.  This software is made
 * available "as is", and
 * THE UNIVERSITY OF WASHINGTON DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
 * WITH REGARD TO THIS SOFTWARE, INCLUDING WITHOUT LIMITATION ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, AND IN
 * NO EVENT SHALL THE UNIVERSITY OF WASHINGTON BE LIABLE FOR ANY SPECIAL,
 * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, TORT
 * (INCLUDING NEGLIGENCE) OR STRICT LIABILITY, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */


#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 "mbx.h"
#include "rfc822.h"
#include "misc.h"
#include "dummy.h"

/* MBX mail routines */


/* Driver dispatch used by MAIL */

DRIVER mbxdriver = {
  "mbx",			/* driver name */
  DR_NAMESPACE|DR_LOCAL|DR_MAIL,/* driver flags */
  (DRIVER *) NIL,		/* next driver */
  mbx_valid,			/* mailbox is valid for us */
  mbx_parameters,		/* manipulate parameters */
  mbx_scan,			/* scan mailboxes */
  mbx_list,			/* list mailboxes */
  mbx_lsub,			/* list subscribed mailboxes */
  NIL,				/* subscribe to mailbox */
  NIL,				/* unsubscribe from mailbox */
  mbx_create,			/* create mailbox */
  mbx_delete,			/* delete mailbox */
  mbx_rename,			/* rename mailbox */
  NIL,				/* status of mailbox */
  mbx_open,			/* open mailbox */
  mbx_close,			/* close mailbox */
  mbx_fetchfast,		/* fetch message "fast" attributes */
  mbx_fetchflags,		/* fetch message flags */
  mbx_fetchstructure,		/* fetch message envelopes */
  mbx_fetchheader,		/* fetch message header only */
  mbx_fetchtext,		/* fetch message body only */
  mbx_fetchbody,		/* fetch message body section */
  NIL,				/* unique identifier */
  mbx_setflag,			/* set message flag */
  mbx_clearflag,		/* clear message flag */
  NIL,				/* search for message based on criteria */
  mbx_ping,			/* ping mailbox to see if still alive */
  mbx_check,			/* check for new messages */
  mbx_expunge,			/* expunge deleted messages */
  mbx_copy,			/* copy messages to another mailbox */
  mbx_append,			/* append string message to mailbox */
  mbx_gc			/* garbage collect stream */
};

				/* prototype stream */
MAILSTREAM mbxproto = {&mbxdriver};

/* MBX mail validate mailbox
 * Accepts: mailbox name
 * Returns: our driver if name is valid, NIL otherwise
 */

DRIVER *mbx_valid (char *name)
{
  char tmp[MAILTMPLEN];
  return mbx_isvalid (name,tmp,T) ? &mbxdriver : NIL;
}


/* MBX mail test for valid mailbox
 * Accepts: mailbox name
 *	    scratch buffer
 *	    non-zero if syntax-only parse
 * Returns: T if valid, NIL otherwise
 */

int mbx_isvalid (char *name,char *tmp,long synonly)
{
  int fd;
  int ret = NIL;
  char *s,hdr[HDRSIZE];
  struct stat sbuf;
  time_t tp[2];
  errno = EINVAL;		/* assume invalid argument */
				/* if file, get its status */
  if ((*name != '{') && (s = mbx_file (tmp,name))) {
				/* done if syntax-only and namespace */
    if (synonly && ((*name == '#') && ((name[1] == 'm') || (name[1] == 'M')) &&
		    ((name[2] == 'b') || (name[2] == 'B')) &&
		    ((name[3] == 'x') || (name[3] == 'X')) &&
		    (name[4] == '/'))) ret = T;
    else if (!stat (s,&sbuf) && (fd = open (tmp,O_RDONLY,NIL)) >= 0) {
      errno = -1;		/* bogus format */
      if (read (fd,hdr,HDRSIZE) == HDRSIZE)
	if ((hdr[0] == '*') && (hdr[1] == 'm') && (hdr[2] == 'b') &&
	    (hdr[3] == 'x') && (hdr[4] == '*') && (hdr[5] == '\015') &&
	    (hdr[6] == '\012') && isxdigit (hdr[7]) && isxdigit (hdr[8]))
	  if (isxdigit (hdr[9]) && isxdigit (hdr[10]) && isxdigit (hdr[11]) &&
	      isxdigit (hdr[12]) && isxdigit (hdr[13]) && isxdigit (hdr[14]) &&
	      isxdigit (hdr[15]) && isxdigit (hdr[16]))
	    if (isxdigit (hdr[17]) && isxdigit (hdr[18]) &&
		isxdigit (hdr[19]) && isxdigit (hdr[20]) &&
		isxdigit (hdr[21]) && isxdigit (hdr[22]) &&
		(hdr[23] == '\015') && (hdr[24] == '\012')) ret = T;
      close (fd);		/* close the file */
      tp[0] = sbuf.st_atime;	/* preserve atime and mtime */
      tp[1] = sbuf.st_mtime;
      utime (tmp,tp);		/* set the times */
    }
  }
  return ret;			/* return what we should */
}


/* MBX manipulate driver parameters
 * Accepts: function code
 *	    function-dependent value
 * Returns: function-dependent return value
 */

void *mbx_parameters (long function,void *value)
{
  return NIL;
}

/* MBX mail scan mailboxes
 * Accepts: mail stream
 *	    reference
 *	    pattern to search
 *	    string to scan
 */

void mbx_scan (MAILSTREAM *stream,char *ref,char *pat,char *contents)
{
  if (stream) dummy_scan (NIL,ref,pat,contents);
}


/* MBX mail list mailboxes
 * Accepts: mail stream
 *	    reference
 *	    pattern to search
 */

void mbx_list (MAILSTREAM *stream,char *ref,char *pat)
{
  if (stream) dummy_list (NIL,ref,pat);
}


/* MBX mail list subscribed mailboxes
 * Accepts: mail stream
 *	    reference
 *	    pattern to search
 */

void mbx_lsub (MAILSTREAM *stream,char *ref,char *pat)
{
  if (stream) dummy_lsub (NIL,ref,pat);
}

/* MBX mail create mailbox
 * Accepts: MAIL stream
 *	    mailbox name to create
 * Returns: T on success, NIL on failure
 */

long mbx_create (MAILSTREAM *stream,char *mailbox)
{
  char *s,*t,mbx[MAILTMPLEN],tmp[HDRSIZE];
  long ret = NIL;
  int i,fd;
  if (!(s = mbx_file (mbx,mailbox))) {
    sprintf (mbx,"Can't create %s: invalid name",mailbox);
    mm_log (mbx,ERROR);
    return NIL;
  }
				/* create underlying file */
  if (!dummy_create (stream,s)) return NIL;
				/* done if made directory */
  if ((s = strrchr (s,'/')) && !s[1]) return T;
  if ((fd = open (mbx,O_WRONLY,
		  (int) mail_parameters (NIL,GET_MBXPROTECTION,NIL))) < 0) {
    sprintf (tmp,"Can't reopen mailbox node %s: %s",mbx,strerror (errno));
    mm_log (tmp,ERROR);
    unlink (mbx);		/* delete the file */
    return NIL;
  }
  memset (tmp,'\0',HDRSIZE);	/* initialize header */
  strcpy (s = tmp,"*mbx*\015\0120000000100000000\015\012");
  for (i = 0; i < NUSERFLAGS; ++i)
    sprintf (s += strlen (s),"%s\015\012",(t = default_user_flag(i)) ? t : "");
  if (write (fd,tmp,HDRSIZE) != HDRSIZE) {
    sprintf (tmp,"Can't initialize mailbox node %s: %s",mbx,strerror (errno));
    mm_log (tmp,ERROR);
    unlink (mbx);		/* delete the file */
    return NIL;
  }
  return close (fd) ? NIL : T;	/* close file */
}


/* MBX mail delete mailbox
 * Accepts: MAIL stream
 *	    mailbox name to delete
 * Returns: T on success, NIL on failure
 */

long mbx_delete (MAILSTREAM *stream,char *mailbox)
{
  return mbx_rename (stream,mailbox,NIL);
}

/* MBX mail rename mailbox
 * Accepts: MAIL stream
 *	    old mailbox name
 *	    new mailbox name (or NIL for delete)
 * Returns: T on success, NIL on failure
 */

long mbx_rename (MAILSTREAM *stream,char *old,char *newname)
{
  long ret = T;
  char *s,tmp[MAILTMPLEN],file[MAILTMPLEN],lock[MAILTMPLEN];
  int ld;
  int fd = open (mbx_file (file,old),O_RDWR,NIL);
				/* lock out non c-client applications */
  if (fd < 0) {			/* open mailbox */
    sprintf (tmp,"Can't open mailbox %s: %s",old,strerror (errno));
    mm_log (tmp,ERROR);
    return NIL;
  }
				/* get parse/append permission */
  if ((ld = mbx_lock (fd,lock)) < 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 %s is in use by another process",old);
    mm_log (tmp,ERROR);
    mbx_unlock (ld,lock);	/* release exclusive parse/append permission */
    return NIL;
  }
  if (newname) {		/* want rename? */
    if (!((s = mbx_file (tmp,newname)) && *s)) {
      sprintf (tmp,"Can't rename mailbox %s to %s: invalid name",old,newname);
      mm_log (tmp,ERROR);
      ret = NIL;		/* set failure */
    }
    if (rename (file,s)) {	/* rename the file */
      sprintf (tmp,"Can't rename mailbox %s to %s: %s",old,newname,
	       strerror (errno));
      mm_log (tmp,ERROR);
      ret = NIL;		/* set failure */
    }
  }
  else if (unlink (file)) {
    sprintf (tmp,"Can't delete mailbox %s: %s",old,strerror (errno));
    mm_log (tmp,ERROR);
    ret = NIL;			/* set failure */
  }
  flock (fd,LOCK_UN);		/* release lock on the file */
  mbx_unlock (ld,lock);		/* release exclusive parse/append permission */
  close (fd);			/* close the file */
				/* recreate file if renamed INBOX */
  if (ret && !strcmp (ucase (strcpy (tmp,old)),"INBOX"))
    mbx_create (NIL,"#mbx/INBOX");
  return ret;			/* return success */
}

/* MBX mail open
 * Accepts: stream to open
 * Returns: stream on success, NIL on failure
 */

MAILSTREAM *mbx_open (MAILSTREAM *stream)
{
  int fd,ld;
  char tmp[MAILTMPLEN];
				/* return prototype for OP_PROTOTYPE call */
  if (!stream) return user_flags (&mbxproto);
  if (LOCAL) {			/* close old file if stream being recycled */
    mbx_close (stream,NIL);	/* dump and save the changes */
    stream->dtb = &mbxdriver;	/* reattach this driver */
    mail_free_cache (stream);	/* clean up cache */
  }
  if (stream->rdonly ||
      (fd = open (mbx_file (tmp,stream->mailbox),O_RDWR,NIL)) < 0) {
    if ((fd = open (mbx_file (tmp,stream->mailbox),O_RDONLY,NIL)) < 0) {
      sprintf (tmp,"Can't open mailbox: %s",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 (MBXLOCAL));
  LOCAL->buf = (char *) fs_get (MAXMESSAGESIZE + 1);
  LOCAL->buflen = MAXMESSAGESIZE;
  LOCAL->hdr = LOCAL->txt = NIL;/* no cached data yet */
  LOCAL->hdrmsgno = LOCAL->txtmsgno = 0;
				/* note if an INBOX or not */
  LOCAL->inbox = !strcmp (ucase (strcpy (LOCAL->buf,stream->mailbox)),"INBOX");
  fs_give ((void **) &stream->mailbox);
  stream->mailbox = cpystr (tmp);
				/* get parse/append permission */
  if ((ld = mbx_lock (fd,tmp)) < 0) {
    mm_log ("Unable to lock open mailbox",ERROR);
    return NIL;
  }
  flock(LOCAL->fd = fd,LOCK_SH);/* bind and lock the file */
  mbx_unlock (ld,tmp);		/* release shared parse permission */
  LOCAL->filesize = HDRSIZE;	/* initialize parsed file size */
  LOCAL->filetime = 0;		/* time not set up yet */
  LOCAL->mustcheck = LOCAL->shouldcheck = LOCAL->newkeyword = NIL;
  stream->sequence++;		/* bump sequence number */
				/* parse mailbox */
  stream->nmsgs = stream->recent = 0;
  if (mbx_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;
  stream->kwd_create = (stream->user_flags[NUSERFLAGS-1] || stream->rdonly) ?
    NIL : T;			/* can we create new user flags? */
  return stream;		/* return stream to caller */
}

/* MBX mail close
 * Accepts: MAIL stream
 *	    close options
 */

void mbx_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) mbx_expunge (stream);
    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->hdr) fs_give ((void **) &LOCAL->hdr);
    if (LOCAL->txt) fs_give ((void **) &LOCAL->txt);
				/* nuke the local data */
    fs_give ((void **) &stream->local);
    stream->dtb = NIL;		/* log out the DTB */
  }
}


/* MBX mail fetch fast information
 * Accepts: MAIL stream
 *	    sequence
 *	    option flags
 */

void mbx_fetchfast (MAILSTREAM *stream,char *sequence,long flags)
{
  return;			/* no-op for local mail */
}


/* MBX mail fetch flags
 * Accepts: MAIL stream
 *	    sequence
 */

void mbx_fetchflags (MAILSTREAM *stream,char *sequence,long flags)
{
  long i;
  if (mbx_ping (stream) && 	/* ping mailbox, get new status for messages */
      ((flags & FT_UID) ? mail_uid_sequence (stream,sequence) :
       mail_sequence (stream,sequence)))
    for (i = 1; i <= stream->nmsgs; i++) 
      if (mail_elt (stream,i)->sequence) mbx_elt (stream,i);
}

/* MBX mail fetch structure
 * Accepts: MAIL stream
 *	    message # to fetch
 *	    pointer to return body
 *	    option flags
 * Returns: envelope of this message, body returned in body value
 *
 * Fetches the "fast" information as well
 */

ENVELOPE *mbx_fetchstructure (MAILSTREAM *stream,unsigned long msgno,
				BODY **body,long flags)
{
  LONGCACHE *lelt;
  ENVELOPE **env;
  BODY **b;
  STRING bs;
  unsigned long i,hdrsize,textsize;
  if (flags & FT_UID) {		/* UID form of call */
    for (i = 1; i <= stream->nmsgs; i++)
      if (mail_uid (stream,i) == msgno)
	return mbx_fetchstructure (stream,i,body,flags & ~FT_UID);
    return NIL;			/* didn't find the UID */
  }
  if (stream->scache) {		/* short cache */
    if (msgno != stream->msgno){/* flush old poop if a different message */
      mail_free_envelope (&stream->env);
      mail_free_body (&stream->body);
    }
    stream->msgno = msgno;
    env = &stream->env;		/* get pointers to envelope and body */
    b = &stream->body;
  }
  else {			/* long cache */
    lelt = mail_lelt (stream,msgno);
    env = &lelt->env;		/* get pointers to envelope and body */
    b = &lelt->body;
  }
  if ((body && !*b) || !*env) {	/* have the poop we need? */
    mail_free_envelope (env);	/* flush old envelope and body */
    mail_free_body (b);
				/* read the header */
    mbx_fetchheader_work (stream,msgno,&hdrsize);
    if (body) {			/* don't bother with text if don't want body */
      mbx_fetchtext_work (stream,msgno,&textsize);
      INIT (&bs,mail_string,(void *) LOCAL->txt,textsize);
    }
    else textsize = 0;		/* no text then */
				/* make sure enough space */
    if ((i = max (hdrsize,textsize)) > LOCAL->buflen) {
      fs_give ((void **) &LOCAL->buf);
      LOCAL->buf = (char *) fs_get ((LOCAL->buflen = i) + 1);
    }
				/* parse envelope and body */
    rfc822_parse_msg (env,body ? b : NIL,LOCAL->hdr,hdrsize,body ? &bs : NIL,
		      mylocalhost (),LOCAL->buf);
  }
  if (body) *body = *b;		/* return the body */
  return *env;			/* return the envelope */
}

/* MBX 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 *mbx_fetchheader (MAILSTREAM *stream,unsigned long msgno,
			 STRINGLIST *lines,unsigned long *len,long flags)
{
  char *hdr;
  unsigned long i;
  if (flags & FT_UID) {		/* UID form of call */
    for (i = 1; i <= stream->nmsgs; i++)
      if (mail_uid (stream,i) == msgno)
	return mbx_fetchheader (stream,i,lines,len,flags & ~FT_UID);
    return NIL;			/* didn't find the UID */
  }
				/* get the header */
  hdr = mbx_fetchheader_work (stream,msgno,&i);
				/* filter if necessary */
  if (lines) i = mail_filter (hdr,i,lines,flags);
  if (len) *len = i;
  return hdr;
}


/* MBX mail fetch message header work
 * Accepts: MAIL stream
 *	    message # to fetch
 *	    pointer to size to return
 * Returns: message header in RFC822 format
 */

char *mbx_fetchheader_work (MAILSTREAM *stream,unsigned long msgno,
			      unsigned long *len)
{
  unsigned long pos = mbx_header (stream,msgno,len);
  if (LOCAL->hdrmsgno != msgno){/* is cache correct? */
    if (LOCAL->hdr) fs_give ((void **) &LOCAL->hdr);
    LOCAL->hdr = (char *) fs_get (1 + *len);
    LOCAL->hdr[*len] = '\0';	/* tie off string */
    LOCAL->hdrmsgno = msgno;	/* note cache */
    lseek (LOCAL->fd,pos,L_SET);/* get to header position */
				/* slurp the data */
    read (LOCAL->fd,LOCAL->hdr,*len);
  }
  return LOCAL->hdr;
}

/* MBX mail fetch message text (body only)
 * Accepts: MAIL stream
 *	    message # to fetch
 *	    pointer to returned header text length
 *	    option flags
 * Returns: message text in RFC822 format
 */

char *mbx_fetchtext (MAILSTREAM *stream,unsigned long msgno,
		       unsigned long *len,long flags)
{
  char *txt;
  unsigned long i;
  MESSAGECACHE *elt;
  if (flags & FT_UID) {		/* UID form of call */
    for (i = 1; i <= stream->nmsgs; i++)
      if (mail_uid (stream,i) == msgno)
	return mbx_fetchtext (stream,i,len,flags & ~FT_UID);
    return NIL;			/* didn't find the UID */
  }
  elt = mbx_elt (stream,msgno);	/* get message status */
  txt = mbx_fetchtext_work (stream,msgno,&i);
				/* if message not seen */
  if (!(flags & FT_PEEK) && !elt->seen) {
    elt->seen = T;		/* mark message as seen */
				/* recalculate status */
    mbx_update_status (stream,msgno,T);
  }
  if (len) *len = i;		/* return size */
  return txt;
}


/* MBX mail fetch message header work
 * Accepts: MAIL stream
 *	    message # to fetch
 *	    pointer to size to return
 * Returns: message header in RFC822 format
 */

char *mbx_fetchtext_work (MAILSTREAM *stream,unsigned long msgno,
			    unsigned long *len)
{
  unsigned long hdrsize;
  unsigned long pos = mbx_header (stream,msgno,&hdrsize);
  *len = mail_elt (stream,msgno)->rfc822_size - hdrsize;
  if (LOCAL->txtmsgno != msgno){/* is cache correct? */
    if (LOCAL->txt) fs_give ((void **) &LOCAL->txt);
    LOCAL->txt = (char *) fs_get (1 + *len);
    LOCAL->txt[*len] = '\0';	/* tie off string */
    LOCAL->txtmsgno = msgno;	/* note cache */
				/* get to text position */
    lseek (LOCAL->fd,pos + hdrsize,L_SET);
				/* slurp the data */
    read (LOCAL->fd,LOCAL->txt,*len);
  }
  return LOCAL->txt;
}

/* MBX fetch message body as a structure
 * Accepts: Mail stream
 *	    message # to fetch
 *	    section specifier
 *	    pointer to length
 *	    option flags
 * Returns: pointer to section of message body
 */

char *mbx_fetchbody (MAILSTREAM *stream,unsigned long msgno,char *s,
		       unsigned long *len,long flags)
{
  BODY *b;
  PART *pt;
  char *t;
  unsigned long offset = 0;
  unsigned long i,base,hdrpos,size = 0;
  unsigned short enc = ENC7BIT;
  MESSAGECACHE *elt;
  if (flags & FT_UID) {		/* UID form of call */
    for (i = 1; i <= stream->nmsgs; i++)
      if (mail_uid (stream,i) == msgno)
	return mbx_fetchbody (stream,i,s,len,flags & ~FT_UID);
    return NIL;			/* didn't find the UID */
  }
  hdrpos = mbx_header (stream,msgno,&base);
  elt = mail_elt (stream,msgno);/* get elt */
				/* make sure have a body */
  if (!(mbx_fetchstructure (stream,msgno,&b,flags & ~FT_UID) && b && s &&
	*s && isdigit (*s))) return NIL;
  if (!(i = strtoul (s,&s,10)))	/* section 0 */
    return *s ? NIL : mbx_fetchheader (stream,msgno,NIL,len,flags);

  do {				/* until find desired body part */
				/* multipart content? */
    if (b->type == TYPEMULTIPART) {
      pt = b->contents.part;	/* yes, find desired part */
      while (--i && (pt = pt->next));
      if (!pt) return NIL;	/* bad specifier */
				/* note new body, check valid nesting */
      if (((b = &pt->body)->type == TYPEMULTIPART) && !*s) return NIL;
      offset = pt->offset;	/* get new offset */
    }
    else if (i != 1) return NIL;/* otherwise must be section 1 */
				/* need to go down further? */
    if (i = *s) switch (b->type) {
    case TYPEMESSAGE:		/* embedded message */
      if (!((*s++ == '.') && isdigit (*s))) return NIL;
				/* get message's body if non-zero */
      if (i = strtoul (s,&s,10)) {
	offset = b->contents.msg.offset;
	b = b->contents.msg.body;
      }
      else {			/* want header */
	size = b->contents.msg.offset - offset;
	b = NIL;		/* make sure the code below knows */
      }
      break;
    case TYPEMULTIPART:		/* multipart, get next section */
      if ((*s++ == '.') && isdigit (*s) && (i = strtoul (s,&s,10)) > 0) break;
    default:			/* bogus subpart specification */
      return NIL;
    }
  } while (i);
  if (b) {			/* looking at a non-multipart body? */
    if (b->type == TYPEMULTIPART) return NIL;
    size = b->size.ibytes;	/* yes, get its size */
    enc = b->encoding;
  }
  else if (!size) return NIL;	/* lose if not getting a header */
				/* if message not seen */
  if (!(flags & FT_PEEK) && !elt->seen) {
    elt->seen = T;		/* mark message as seen */
				/* recalculate status */
    mbx_update_status (stream,msgno,T);
  }
				/* move to that place in the data */
  lseek (LOCAL->fd,hdrpos + base + offset,L_SET);
				/* slurp the data */
  t = (char *) fs_get (1 + size);
  read (LOCAL->fd,t,size);
  rfc822_contents(&LOCAL->buf,&LOCAL->buflen,len,t,size,enc);
  fs_give ((void **) &t);	/* flush readin buffer */
  return LOCAL->buf;
}

/* MBX locate header for a message
 * Accepts: MAIL stream
 *	    message number
 *	    pointer to returned header size
 * Returns: position of header in file
 */

unsigned long mbx_header (MAILSTREAM *stream,unsigned long msgno,
			    unsigned long *size)
{
  long siz;
  long i = 0;
  int q = 0;
  char *s,tmp[MAILTMPLEN];
  MESSAGECACHE *elt = mbx_elt (stream,msgno);
  long pos = elt->data1 + elt->data2;
  if (!(*size = elt->data3)) {	/* is header size known? */
    lseek (LOCAL->fd,pos,L_SET);/* get to header position */
				/* search message for CRLF CRLF */
    for (siz = 1; siz <= elt->rfc822_size; siz++) {
				/* read another buffer as necessary */
      if (--i <= 0)		/* buffer empty? */
	if (read (LOCAL->fd,s = tmp,
		  i = min (elt->rfc822_size - siz,(long) MAILTMPLEN)) < 0)
	  return pos;		/* I/O error? */
      switch (q) {		/* sniff at buffer */
      case 0:			/* first character */
	q = (*s++ == '\015') ? 1 : 0;
	break;
      case 1:			/* second character */
	q = (*s++ == '\012') ? 2 : 0;
	break;
      case 2:			/* third character */
	q = (*s++ == '\015') ? 3 : 0;
	break;
      case 3:			/* fourth character */
	if (*s++ == '\012') {	/* have the sequence? */
				/* yes, note for later */
	  elt->data3 = *size = siz;
	  return pos;		/* return to caller */
	}
	q = 0;			/* lost... */
	break;
      }
    }
  }
  return pos;			/* have position */
}

/* MBX mail set flag
 * Accepts: MAIL stream
 *	    sequence
 *	    flag(s)
 *	    option flags
 */

void mbx_setflag (MAILSTREAM *stream,char *sequence,char *flag,long flags)
{
  MESSAGECACHE *elt;
  struct stat sbuf;
  long i,f;
  unsigned long uf;
				/* find last assigned user flag */
  for (i = 0; i < NUSERFLAGS && stream->user_flags[i]; ++i);
				/* parse flags */
  f = mail_parse_flags (stream,flag,&uf);
				/* note if any new keywords appeared */
  if (i < NUSERFLAGS && stream->user_flags[i]) LOCAL->newkeyword = T;
  if (!(f || uf)) return;	/* no-op if no flags to modify */
  if (LOCAL->filetime && !LOCAL->shouldcheck) {
    fstat (LOCAL->fd,&sbuf);	/* get current write time */
    if (LOCAL->filetime < sbuf.st_mtime) LOCAL->shouldcheck = T;
  }
				/* get sequence and loop on it */
  if ((flags & ST_UID) ? mail_uid_sequence (stream,sequence) :
      mail_sequence (stream,sequence))
    for (i = 1; i <= stream->nmsgs; i++)
      if ((elt = mail_elt (stream,i))->sequence) {
	mbx_elt (stream,i);	/* set all requested flags */
	if (f&fSEEN) elt->seen = T;
	if (f&fDELETED) elt->deleted = T;
	if (f&fFLAGGED) elt->flagged = T;
	if (f&fANSWERED) elt->answered = T;
	if (f&fDRAFT) elt->draft = T;
	elt->user_flags |= uf;
				/* recalculate status */
	mbx_update_status (stream,i,NIL);
      }
  if (!stream->rdonly) {	/* make sure the update takes */
    fsync (LOCAL->fd);
    fstat (LOCAL->fd,&sbuf);	/* get current write time */
    LOCAL->filetime = sbuf.st_mtime;
  }
}

/* MBX mail clear flag
 * Accepts: MAIL stream
 *	    sequence
 *	    flag(s)
 *	    option flags
 */

void mbx_clearflag (MAILSTREAM *stream,char *sequence,char *flag,long flags)
{
  MESSAGECACHE *elt;
  struct stat sbuf;
  long i,f;
  unsigned long uf;
				/* find last assigned user flag */
  for (i = 0; i < NUSERFLAGS && stream->user_flags[i]; ++i);
				/* parse flags */
  f = mail_parse_flags (stream,flag,&uf);
				/* note if any new keywords appeared */
  if (i < NUSERFLAGS && stream->user_flags[i]) LOCAL->newkeyword = T;
  if (!(f || uf)) return;	/* no-op if no flags to modify */
  if (LOCAL->filetime && !LOCAL->shouldcheck) {
    fstat (LOCAL->fd,&sbuf);	/* get current write time */
    if (LOCAL->filetime < sbuf.st_mtime) LOCAL->shouldcheck = T;
  }
				/* get sequence and loop on it */
  if ((flags & ST_UID) ? mail_uid_sequence (stream,sequence) :
      mail_sequence (stream,sequence))
    for (i = 1; i <= stream->nmsgs; i++)
      if ((elt = mail_elt (stream,i))->sequence) {
	mbx_elt (stream,i);	/* clear all requested flags */
	if (f&fSEEN) elt->seen = NIL;
	if (f&fDELETED) elt->deleted = NIL;
	if (f&fFLAGGED) elt->flagged = NIL;
	if (f&fANSWERED) elt->answered = NIL;
	if (f&fDRAFT) elt->draft = NIL;
	elt->user_flags &= ~uf;
				/* recalculate status */
	mbx_update_status (stream,i,NIL);
      }
  if (!stream->rdonly) {	/* make sure the update takes */
    fsync (LOCAL->fd);
    fstat (LOCAL->fd,&sbuf);	/* get current write time */
    LOCAL->filetime = sbuf.st_mtime;
  }
}

/* MBX mail ping mailbox
 * Accepts: MAIL stream
 * Returns: T if stream still alive, NIL if not
 */

long mbx_ping (MAILSTREAM *stream)
{
  long i = 1;
  long r = NIL;
  int ld;
  char lock[MAILTMPLEN];
  struct stat sbuf;
  if (stream && LOCAL) {	/* only if stream already open */
    if (LOCAL->filetime && !(LOCAL->mustcheck || LOCAL->shouldcheck)) {
      fstat (LOCAL->fd,&sbuf);	/* get current write time */
      if (LOCAL->filetime < sbuf.st_mtime) LOCAL->shouldcheck = T;
    }
				/* check for changed message status */
    if (LOCAL->mustcheck || LOCAL->shouldcheck) {
      if (LOCAL->shouldcheck)	/* babble when we do this unilaterally */
	mm_notify (stream,"[CHECK] Checking for flag updates",NIL);
      while (i <= stream->nmsgs) mbx_elt (stream,i++);
      LOCAL->mustcheck = LOCAL->shouldcheck = NIL;
    }
				/* get parse/append permission */
    if ((ld = mbx_lock (LOCAL->fd,lock)) >= 0) {
				/* parse resulting mailbox */
      r = (mbx_parse (stream)) ? T : NIL;
      mbx_unlock (ld,lock);	/* release shared parse/append permission */
    }
				/* snarf if this is a read-write inbox */
    if (stream && LOCAL && LOCAL->inbox && !stream->rdonly) {
      mbx_snarf (stream);
				/* get parse/append permission */
      if ((ld = mbx_lock (LOCAL->fd,lock)) >= 0) {
				/* parse resulting mailbox */
	r = (mbx_parse (stream)) ? T : NIL;
	mbx_unlock (ld,lock);	/* release shared parse/append permission */
      }
    }
  }
  return r;			/* return result of the parse */
}


/* MBX mail check mailbox (reparses status too)
 * Accepts: MAIL stream
 */

void mbx_check (MAILSTREAM *stream)
{
				/* mark that a check is desired */
  if (LOCAL) LOCAL->mustcheck = T;
  if (mbx_ping (stream)) mm_log ("Check completed",(long) NIL);
}

/* MBX mail snarf messages from system inbox
 * Accepts: MAIL stream
 */

void mbx_snarf (MAILSTREAM *stream)
{
  unsigned long i = 0;
  unsigned long r,j;
  struct stat sbuf;
  struct iovec iov[3];
  char lock[MAILTMPLEN];
  MESSAGECACHE *elt;
  MAILSTREAM *sysibx = NIL;
  int ld;
				/* give up if can't get exclusive permission */
  if ((!strcmp (sysinbox (),stream->mailbox)) ||
      ((ld = mbx_lock (LOCAL->fd,lock)) < 0)) return;
  mm_critical (stream);		/* go critical */
  stat (sysinbox (),&sbuf);	/* see if anything there */
  if (sbuf.st_size) {		/* non-empty? */
    fstat (LOCAL->fd,&sbuf);	/* yes, get current file size */
				/* sizes match and can get sysibx mailbox? */
    if ((sbuf.st_size == LOCAL->filesize) && 
	(sysibx = mail_open (sysibx,sysinbox (),OP_SILENT)) &&
	(!sysibx->rdonly) && (r = sysibx->nmsgs)) {
				/* yes, go to end of file in our mailbox */
      lseek (LOCAL->fd,sbuf.st_size,L_SET);
				/* for each message in sysibx mailbox */
      while (r && (++i <= sysibx->nmsgs)) {
				/* snarf message from system INBOX */
	iov[1].iov_base = cpystr (mail_fetchheader_full (sysibx,i,NIL,&j,NIL));
	iov[1].iov_len = j;
	iov[2].iov_base = mail_fetchtext_full (sysibx,i,&j,NIL);
	iov[2].iov_len = j;
				/* calculate header line */
	mail_date ((iov[0].iov_base = LOCAL->buf),elt = mail_elt (sysibx,i));
	sprintf (LOCAL->buf + strlen (LOCAL->buf),
		 ",%ld;00000000%04x-00000000\015\012",
		 iov[1].iov_len + iov[2].iov_len,(fSEEN * elt->seen) +
		 (fDELETED * elt->deleted) + (fFLAGGED * elt->flagged) +
		 (fANSWERED * elt->answered) + (fDRAFT * elt->draft));
	iov[0].iov_len = strlen (iov[0].iov_base);
				/* copy message to new mailbox */
	if ((writev (LOCAL->fd,iov,3) < 0) || fsync (LOCAL->fd)) {
	  sprintf (LOCAL->buf,"Can't copy new mail: %s",strerror (errno));
	  mm_log (LOCAL->buf,ERROR);
	  ftruncate (LOCAL->fd,sbuf.st_size);
	  r = 0;		/* flag that we have lost big */
	}
	fs_give ((void **) &iov[1].iov_base);
      }
      fstat (LOCAL->fd,&sbuf);	/* yes, get current file size */
      LOCAL->filetime = sbuf.st_mtime;
      if (r) {			/* delete all the messages we copied */
	for (i = 1; i <= r; i++) mail_elt (sysibx,i)->deleted = T;
	mail_expunge (sysibx);	/* now expunge all those messages */
      }
    }
    if (sysibx) mail_close (sysibx);
  }
  mm_nocritical (stream);	/* release critical */
  mbx_unlock (ld,lock);		/* release exclusive parse/append permission */
}

/* MBX mail expunge mailbox
 * Accepts: MAIL stream
 */

void mbx_expunge (MAILSTREAM *stream)
{
  struct stat sbuf;
  off_t pos = HDRSIZE;
  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;
				/* do nothing if stream dead */
  if (!mbx_ping (stream)) return;
  if (stream->rdonly) {		/* won't do on readonly files! */
    mm_log ("Expunge ignored on readonly mailbox",WARN);
    return;
  }
  if (LOCAL->filetime && !LOCAL->shouldcheck) {
    fstat (LOCAL->fd,&sbuf);	/* get current write time */
    if (LOCAL->filetime < sbuf.st_mtime) LOCAL->shouldcheck = T;
  }
  /* The cretins who designed flock() created a window of vulnerability in
   * upgrading locks from shared to exclusive or downgrading from exclusive
   * to shared.  Rather than maintain the lock at shared status at a minimum,
   * flock() actually *releases* the former lock.  Obviously they never talked
   * to any database guys.  Fortunately, we have the parse/append permission
   * lock.  If we require this lock before going exclusive on the mailbox,
   * another process can not sneak in and steal the exclusive mailbox lock on
   * us, because it will block on trying to get parse/append permission first.
   */
				/* get parse/append permission */
  if ((ld = mbx_lock (LOCAL->fd,lock)) < 0) {
    mm_log ("Unable to lock expunge mailbox",ERROR);
    return;
  }
				/* get exclusive access */
  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);
    mbx_unlock (ld,lock);	/* release exclusive parse/append permission */
    return;
  }
  mbx_gc (stream,GC_TEXTS);	/* flush texts */

  mm_critical (stream);		/* go critical */
  recent = stream->recent;	/* get recent now that pinged and locked */
  while (i <= stream->nmsgs) {	/* for each message */
    elt = mbx_elt (stream,i);	/* get cache element */
				/* number of bytes to smash or preserve */
    k = elt->data2 + elt->rfc822_size;
    if (elt->deleted) {		/* if deleted */
      if (elt->recent) --recent;/* if recent, note one less recent message */
      delta += k;		/* number of bytes to delete */
      mail_expunged (stream,i);	/* notify upper levels */
      n++;			/* count up one more expunged message */
    }
    else if (i++ && delta) {	/* preserved message */
      j = elt->data1;		/* first byte to preserve */
      do {			/* read from source position */
	m = min (k,LOCAL->buflen);
	lseek (LOCAL->fd,j,L_SET);
	read (LOCAL->fd,LOCAL->buf,(unsigned int) m);
	pos = j - delta;	/* write to destination position */
	lseek (LOCAL->fd,pos,L_SET);
	write (LOCAL->fd,LOCAL->buf,(unsigned int) m);
	pos += m;		/* new position */
	j += m;			/* next chunk, perhaps */
      } while (k -= m);		/* until done */
      elt->data1 -= delta;	/* note the new address of this text */
    }
    else pos = elt->data1 + k;	/* preserved but no deleted messages */
  }
  if (n) {			/* truncate file after last message */
    if (pos != (LOCAL->filesize -= delta)) {
      sprintf (LOCAL->buf,"Calculated size mismatch %ld != %ld, delta = %ld",
	       pos,LOCAL->filesize,delta);
      mm_log (LOCAL->buf,WARN);
      LOCAL->filesize = pos;	/* fix it then */
    }
    ftruncate (LOCAL->fd,LOCAL->filesize);
    sprintf (LOCAL->buf,"Expunged %ld 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 */
  LOCAL->filetime = sbuf.st_mtime;
  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 */
  mbx_unlock (ld,lock);		/* release exclusive parse/append permission */
}

/* MBX mail copy message(s)
 * Accepts: MAIL stream
 *	    sequence
 *	    destination mailbox
 *	    copy options
 * Returns: T if success, NIL if failed
 */

long mbx_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options)
{
  long i;
  struct stat sbuf;
  MESSAGECACHE *elt;
  if (!(((options & CP_UID) ? mail_uid_sequence (stream,sequence) :
	 mail_sequence (stream,sequence)) &&
	mbx_copy_messages (stream,mailbox))) return NIL;
				/* delete all requested messages */
  if (options & CP_MOVE) for (i = 1; i <= stream->nmsgs; i++)
    if ((elt = mbx_elt (stream,i))->sequence) {
      elt->deleted = T;		/* mark message deleted */
				/* recalculate status */
      mbx_update_status (stream,i,NIL);
    }
  if (!stream->rdonly) {	/* make sure the update takes */
    fsync (LOCAL->fd);
    fstat (LOCAL->fd,&sbuf);	/* get current write time */
    LOCAL->filetime = sbuf.st_mtime;
  }
  return LONGT;
}

/* MBX mail append message from stringstruct
 * Accepts: MAIL stream
 *	    destination mailbox
 *	    stringstruct of messages to append
 * Returns: T if append successful, else NIL
 */

long mbx_append (MAILSTREAM *stream,char *mailbox,char *flags,char *date,
		   STRING *message)
{
  struct stat sbuf;
  int fd,ld;
  char *s,tmp[MAILTMPLEN],file[MAILTMPLEN],lock[MAILTMPLEN];
  time_t tp[2];
  MESSAGECACHE elt;
  long i = 0;
  long size = SIZE (message);
  long ret = LONGT;
  unsigned long uf = 0;
  long f = mail_parse_flags (stream ? stream : user_flags (&mbxproto),
			     flags,&uf);
				/* reverse bits (dontcha wish we had CIRC?) */
  if (date) {			/* want to preserve date? */
				/* yes, parse date into an elt */
    if (!mail_parse_date (&elt,date)) {
      sprintf (tmp,"Bad date in append: %s",date);
      mm_log (tmp,ERROR);
      return NIL;
    }
  }
				/* N.B.: can't use LOCAL->buf for tmp */
				/* make sure valid mailbox */
  if (!mbx_isvalid (mailbox,tmp,NIL)) switch (errno) {
  case ENOENT:			/* no such file? */
    mm_notify (stream,"[TRYCREATE] Must create mailbox before append",NIL);
    return NIL;
  case 0:			/* merely empty file? */
    break;
  case EINVAL:
    sprintf (tmp,"Invalid MBX-format mailbox name: %s",mailbox);
    mm_log (tmp,ERROR);
    return NIL;
  default:
    sprintf (tmp,"Not a MBX-format mailbox: %s",mailbox);
    mm_log (tmp,ERROR);
    return NIL;
  }
  if ((fd = open (mbx_file (file,mailbox),O_RDWR|O_CREAT,
		  S_IREAD|S_IWRITE)) < 0) {
    sprintf (tmp,"Can't open append mailbox: %s",strerror (errno));
    mm_log (tmp,ERROR);
    return NIL;
  }
				/* get parse/append permission */
  if ((ld = mbx_lock (fd,lock)) < 0) {
    mm_log ("Unable to lock append mailbox",ERROR);
    return NIL;
  }
  s = (char *) fs_get (size);	/* copy message */
  for (i = 0; i < size; s[i++] = SNX (message));

  mm_critical (stream);		/* go critical */
  fstat (fd,&sbuf);		/* get current file size */
  lseek (fd,sbuf.st_size,L_SET);/* move to end of file */
  if (date) mail_date(tmp,&elt);/* write preseved date */
  else internal_date (tmp);	/* get current date in IMAP format */
				/* add remainder of header */
  sprintf (tmp+26,",%ld;%08lx%04x-00000000\015\012",size,uf,f);
				/* write header */
  if ((write (fd,tmp,strlen (tmp)) < 0) || ((write (fd,s,size)) < 0) ||
      fsync (fd)) {
    sprintf (tmp,"Message append failed: %s",strerror (errno));
    mm_log (tmp,ERROR);
    ftruncate (fd,sbuf.st_size);
    ret = NIL;
  }
  tp[0] = sbuf.st_atime;	/* preserve atime and mtime */
  tp[1] = sbuf.st_mtime;
  utime (file,tp);		/* set the times */
  mbx_unlock (ld,lock);		/* release exclusive parse/append permission */
  close (fd);			/* close the file */
  mm_nocritical (stream);	/* release critical */
  fs_give ((void **) &s);	/* flush the buffer */
  return ret;
}

/* MBX garbage collect stream
 * Accepts: Mail stream
 *	    garbage collection flags
 */

void mbx_gc (MAILSTREAM *stream,long gcflags)
{
  if (gcflags & GC_TEXTS) {	/* flush texts */
    LOCAL->hdrmsgno = LOCAL->txtmsgno = 0;
    if (LOCAL->hdr) fs_give ((void **) &LOCAL->hdr);
    if (LOCAL->txt) fs_give ((void **) &LOCAL->txt);
  }
}

/* Internal routines */


/* MBX mail lock file for parse/append permission
 * Accepts: file descriptor
 *	    lock file name buffer
 * Returns: file descriptor of lock or -1 if failure
 */

int mbx_lock (int fd,char *lock)
{
  int ld;
  struct stat sbuf;
				/* get data for this file */
  if (fstat (fd,&sbuf)) return -1;
				/* make temporary file name */
  sprintf (lock,"/tmp/.%hx.%lx",sbuf.st_dev,sbuf.st_ino);
  if ((ld = open (lock,O_RDWR|O_CREAT,
		  (int) mail_parameters (NIL,GET_LOCKPROTECTION,NIL))) < 0)
    return -1;
  flock (ld,LOCK_EX);		/* get this lock */
  return ld;			/* return locking file descriptor */
}


/* MBX mail unlock file for parse/append permission
 * Accepts: file descriptor
 *	    lock file name from mbx_lock()
 */

void mbx_unlock (int fd,char *lock)
{
  unlink (lock);		/* delete the file */
  flock (fd,LOCK_UN);		/* unlock it */
  close (fd);			/* close it */
}


/* MBX mail generate file string
 * Accepts: temporary buffer to write into
 *	    mailbox name string
 * Returns: local file string or NIL if failure
 */

char *mbx_file (char *dst,char *name)
{
  char *s,tmp[MAILTMPLEN];
				/* permit #mbx namespace */
  if ((*name == '#') && ((name[1] == 'm') || (name[1] == 'M')) &&
      ((name[2] == 'b') || (name[2] == 'B')) &&
      ((name[3] == 'x') || (name[3] == 'X')) && (name[4] == '/')) name += 5;
  s = mailboxfile (dst,name);
				/* return our standard inbox */
  return (s && !*s) ? mailboxfile (dst,"~/INBOX") : s;
}

/* MBX mail parse mailbox
 * Accepts: MAIL stream
 * Returns: T if parse OK
 *	    NIL if failure, stream aborted
 */

long mbx_parse (MAILSTREAM *stream)
{
  struct stat sbuf;
  MESSAGECACHE *elt = NIL;
  char c,*s,*t,*x;
  char tmp[MAILTMPLEN];
  unsigned long i,j;
  long curpos = LOCAL->filesize;
  unsigned long nmsgs = stream->nmsgs;
  unsigned long recent = stream->recent;
  unsigned long lastuid = 0;
  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);
    mbx_close (stream,NIL);
    return NIL;
  }
  lseek (LOCAL->fd,0,L_SET);	/* rewind file */
				/* read internal header */
  read (LOCAL->fd,LOCAL->buf,HDRSIZE);
  LOCAL->buf[HDRSIZE] = '\0';	/* tie off header */
  c = LOCAL->buf[15];		/* save first character of last UID */
  LOCAL->buf[15] = '\0';
				/* parse UID validity */
  stream->uid_validity = strtoul (LOCAL->buf + 7,NIL,16);
  LOCAL->buf[15] = c;		/* restore first character of last UID */
				/* parse last UID */
  stream->uid_last = strtoul (LOCAL->buf + 15,NIL,16);
				/* parse user flags */
  for (i = 0, s = LOCAL->buf + 25; i < NUSERFLAGS && (t = strchr (s,'\015'));
       i++, s = t + 2) {
    *t = '\0';			/* tie off flag */
    if (*s && !stream->user_flags[i]) stream->user_flags[i] = cpystr (s);
  }

  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 %ld, size = %ld: %s",
	       curpos,sbuf.st_size,i ? strerror (errno) : "no data read");
      mm_log (tmp,ERROR);
      mbx_close (stream,NIL);
      return NIL;
    }
    LOCAL->buf[i] = '\0';	/* tie off buffer just in case */
    if (!((s = strchr (LOCAL->buf,'\015')) && (s[1] == '\012'))) {
      sprintf (tmp,"Unable to find CRLF at %ld in %ld bytes, text: %s",
	       curpos,i,LOCAL->buf);
      mm_log (tmp,ERROR);
      mbx_close (stream,NIL);
      return NIL;
    }
    *s = '\0';			/* tie off header line */
    i = (s + 2) - LOCAL->buf;	/* note start of text offset */
    if (!((s = strchr (LOCAL->buf,',')) && (t = strchr (s+1,';')))) {
      sprintf (tmp,"Unable to parse internal header at %ld: %s",curpos,
	       LOCAL->buf);
      mm_log (tmp,ERROR);
      mbx_close (stream,NIL);
      return NIL;
    }
    *s++ = '\0'; *t++ = '\0';	/* tie off fields */

				/* intantiate an elt for this message */
    (elt = mail_elt (stream,++nmsgs))->valid = T;
    elt->data1 = curpos;	/* note file offset of header */
    elt->data2 = 0;		/* in case error */
    elt->data3 = 0;		/* header size not known yet */
				/* parse the header components */
    if (mail_parse_date (elt,LOCAL->buf) &&
	(elt->rfc822_size = strtoul (x = s,&s,10)) && (!(s && *s)))
      if (isxdigit (t[0]) && isxdigit (t[1]) && isxdigit (t[2]) &&
	  isxdigit (t[3]) && isxdigit (t[4]) && isxdigit (t[5]) &&
	  isxdigit (t[6]) && isxdigit (t[7]) && isxdigit (t[8]) &&
	  isxdigit (t[9]) && isxdigit (t[10]) && isxdigit (t[11]))
	if ((t[12] == '-') && isxdigit (t[13]) && isxdigit (t[14]) &&
	    isxdigit (t[15]) && isxdigit (t[16]) && isxdigit (t[17]) &&
	    isxdigit (t[18]) && isxdigit (t[19]) && isxdigit (t[20]))
	  elt->data2 = i;	/* note offset from header of message */
    if (!elt->data2) {
      sprintf (tmp,"Unable to parse internal header elements at %ld: %s,%s;%s",
	       curpos,LOCAL->buf,x,t);
      mm_log (tmp,ERROR);
      mbx_close (stream,NIL);
      return NIL;
    }
				/* make sure didn't run off end of file */
    if ((curpos += (elt->rfc822_size + i)) > sbuf.st_size) {
      mm_log ("Last message runs past end of file",ERROR);
      mbx_close (stream,NIL);
      return NIL;
    }
    c = t[8];			/* remember first system flags byte */
    t[8] = t[12] = t[21] = '\0';/* tie off flags */
				/* get user flags value */
    elt->user_flags = strtoul (t,NIL,16);
    t[8] = c;			/* restore first system flags byte */
				/* calculate system flags */
    if ((j = strtoul (t+8,NIL,16)) & 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;

				/* have a valid UID for this message yet? */
    if ((elt->uid = strtoul (t+13,NIL,16)) &&
	((elt->uid <= lastuid) || (elt->uid > stream->uid_last))) {
      sprintf (tmp,"Invalid UID %08x in message %ld, rebuilding UIDs",
	       elt->uid,elt->msgno);
      mm_log (tmp,WARN);
      elt->uid = 0;		/* lose this UID */
				/* restart UID validity and last UID */
      stream->uid_validity = time (0);
      stream->uid_last = lastuid;
    }
    if (!elt->uid) {		/* UID assigned yet? */
      elt->recent = T;		/* no, mark as recent */
      recent++;			/* count up a new recent message */
				/* assign new UID */
      elt->uid = ++stream->uid_last;
      mbx_update_status (stream,elt->msgno,NIL);
    }
    lastuid = elt->uid;		/* update last parsed UID */
  }
  mbx_update_header (stream);	/* update header */
  fsync (LOCAL->fd);		/* make sure all the UID updates 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;
  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 */
}

/* MBX copy messages
 * Accepts: MAIL stream
 *	    mailbox copy vector
 *	    mailbox name
 * Returns: T if success, NIL if failed
 */

long mbx_copy_messages (MAILSTREAM *stream,char *mailbox)
{
  struct stat sbuf;
  time_t tp[2];
  MESSAGECACHE *elt;
  unsigned long i,j,k;
  long ret = LONGT;
  int fd,ld;
  char file[MAILTMPLEN],lock[MAILTMPLEN];
				/* make sure valid mailbox */
  if (!mbx_isvalid (mailbox,LOCAL->buf,NIL)) 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 EINVAL:
    sprintf (LOCAL->buf,"Invalid MBX-format mailbox name: %s",mailbox);
    mm_log (LOCAL->buf,ERROR);
    return NIL;
  default:
    sprintf (LOCAL->buf,"Not a MBX-format mailbox: %s",mailbox);
    mm_log (LOCAL->buf,ERROR);
    return NIL;
  }
				/* got file? */  
  if ((fd=open(mbx_file(file,mailbox),O_RDWR|O_CREAT,S_IREAD|S_IWRITE))<0) {
    sprintf (LOCAL->buf,"Unable to open copy mailbox: %s",strerror (errno));
    mm_log (LOCAL->buf,ERROR);
    return NIL;
  }
  mm_critical (stream);		/* go critical */
				/* get parse/append permission */
  if ((ld = mbx_lock (fd,lock)) < 0) {
    mm_log ("Unable to lock copy mailbox",ERROR);
    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->data1,L_SET);
				/* number of bytes to copy */
      k = elt->data2 + elt->rfc822_size;
      do {			/* read from source position */
	j = min (k,LOCAL->buflen);
	read (LOCAL->fd,LOCAL->buf,(unsigned int) j);
	if ((write (fd,LOCAL->buf,(unsigned int) j) < 0) || fsync (fd)) {
	  sprintf (LOCAL->buf,"Unable to write message: %s",strerror (errno));
	  mm_log (LOCAL->buf,ERROR);
	  ftruncate (fd,sbuf.st_size);
	  j = k;
	  ret = NIL;		/* note error */
	  break;
	}
      } while (k -= j);		/* until done */
    }
  tp[0] = sbuf.st_atime;	/* preserve atime and mtime */
  tp[1] = sbuf.st_mtime;
  utime (file,tp);		/* set the times */
  mbx_unlock (ld,lock);		/* release exclusive parse/append permission */
  close (fd);			/* close the file */
  mm_nocritical (stream);	/* release critical */
  return ret;
}

/* MBX get cache element with status updating from file
 * Accepts: MAIL stream
 *	    message number
 * Returns: cache element
 */

MESSAGECACHE *mbx_elt (MAILSTREAM *stream,unsigned long msgno)
{
  unsigned long sysflags;
  char c;
  MESSAGECACHE *elt = mail_elt (stream,msgno);
  unsigned long oldsysflags = (elt->seen ? fSEEN : NIL) |
    (elt->deleted ? fDELETED : NIL) | (elt->flagged ? fFLAGGED : NIL) |
      (elt->answered ? fANSWERED : NIL) | (elt->draft ? fDRAFT : NIL);
  unsigned long olduserflags = elt->user_flags;
				/* set the seek pointer */
  lseek (LOCAL->fd,(off_t) elt->data1 + elt->data2 - 23,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);
  }
  LOCAL->buf[12] = '\0';	/* tie off buffer */
				/* calculate system flags */
  sysflags = strtoul (LOCAL->buf+8,NIL,16);
  elt->seen = sysflags & fSEEN ? T : NIL;
  elt->deleted = sysflags & fDELETED ? T : NIL;
  elt->flagged = sysflags & fFLAGGED ? T : NIL;
  elt->answered = sysflags & fANSWERED ? T : NIL;
  elt->draft = sysflags & fDRAFT ? T : NIL;
  c = LOCAL->buf[8];		/* remember first system flags byte */
  LOCAL->buf[8] = '\0';		/* tie off flags */
				/* get user flags value */
  elt->user_flags = strtoul (LOCAL->buf,NIL,16);
  LOCAL->buf[8] = c;		/* restore first system flags byte */
  if ((oldsysflags != sysflags) || (olduserflags != elt->user_flags))
    mm_flags (stream,msgno);	/* let top level know */
  return elt;
}

/* MBX update header
 * Accepts: MAIL stream
 */

void mbx_update_header (MAILSTREAM *stream)
{
  int i;
  char *s = LOCAL->buf;
  memset (s,'\0',HDRSIZE);	/* initialize header */
  sprintf (s,"*mbx*\015\012%08lx%08lx\015\012",
	   stream->uid_validity,stream->uid_last);
  for (i = 0; i < NUSERFLAGS; ++i)
    sprintf (s += strlen (s),"%s\015\012",
	     stream->user_flags[i] ? stream->user_flags[i] : "");
  lseek (LOCAL->fd,0,L_SET);	/* rewind file */
				/* write new header */
  write (LOCAL->fd,LOCAL->buf,HDRSIZE);
}


/* MBX update status string
 * Accepts: MAIL stream
 *	    message number
 *	    flag saying whether or not to sync
 */

void mbx_update_status (MAILSTREAM *stream,unsigned long msgno,long syncflag)
{
  MESSAGECACHE *elt = mail_elt (stream,msgno);
  struct stat sbuf;
  if (!stream->rdonly) {	/* not if readonly you don't */
    if (LOCAL->newkeyword) {	/* defined a new keyword? */
      mbx_update_header (stream);
      LOCAL->newkeyword = NIL;	/* don't do this again */
    }
				/* print new flag string */
    sprintf (LOCAL->buf,"%08lx%04x-%08lx",elt->user_flags,
	     (fSEEN * elt->seen) + (fDELETED * elt->deleted) +
	     (fFLAGGED * elt->flagged) + (fANSWERED * elt->answered) +
	     (fDRAFT * elt->draft),elt->uid);
				/* get to that place in the file */
    lseek (LOCAL->fd,(off_t) elt->data1 + elt->data2 - 23,L_SET);
				/* write new flags and UID */
    write (LOCAL->fd,LOCAL->buf,21);
				/* sync if requested */
    if (syncflag) fsync (LOCAL->fd);
    fstat (LOCAL->fd,&sbuf);	/* get new write time */
    LOCAL->filetime = sbuf.st_mtime;
  }
}


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