mix.c

广泛使用的邮件服务器！同时

  return (char *) LOCAL->buf + i;
}

/* MIX mail fetch message text (body only)
 * Accepts: MAIL stream
 *	    message # to fetch
 *	    pointer to returned stringstruct
 *	    option flags
 * Returns: T on success, NIL on failure
 */

long mix_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags)
{
  unsigned long i;
  FDDATA d;
  MESSAGECACHE *elt;
				/* UID call "impossible" */
  if (flags & FT_UID) return NIL;
  elt = mail_elt (stream,msgno);
				/* is message in current message file? */
  if ((LOCAL->msgfd < 0) || (elt->private.spare.data != LOCAL->curmsg)) {
    if (LOCAL->msgfd >= 0) close (LOCAL->msgfd);
    if ((LOCAL->msgfd = open (mix_file_data (LOCAL->buf,stream->mailbox,
					     elt->private.spare.data),
					     O_RDONLY,NIL)) < 0) return NIL;
				/* got file */
    LOCAL->curmsg = elt->private.spare.data;
  }    
				/* doing non-peek fetch? */
  if (!(flags & FT_PEEK) && !elt->seen) {
    FILE *idxf;			/* yes, process metadata/index/status */
    FILE *statf = mix_parse (stream,&idxf,NIL,LONGT);
    elt->seen = T;		/* mark as seen */
    MM_FLAGS (stream,elt->msgno);
				/* update status file if possible */
    if (statf && !stream->rdonly) {
      elt->private.mod = LOCAL->statusseq = mix_modseq (LOCAL->statusseq);
      mix_status_update (stream,statf,NIL);
    }
    if (idxf) fclose (idxf);	/* release index and status file */
    if (statf) fclose (statf);
  } 
  d.fd = LOCAL->msgfd;		/* set up file descriptor */
				/* offset of message text */
  d.pos = elt->private.special.offset + elt->private.msg.header.offset +
    elt->private.msg.header.text.size;
  d.chunk = LOCAL->buf;		/* initial buffer chunk */
  d.chunksize = CHUNKSIZE;	/* chunk size */
  INIT (bs,fd_string,&d,elt->rfc822_size - elt->private.msg.header.text.size);
  return T;
}

/* MIX mail modify flags
 * Accepts: MAIL stream
 *	    sequence
 *	    flag(s)
 *	    option flags
 */

void mix_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags)
{
  MESSAGECACHE *elt;
  unsigned long i,uf,ffkey;
  long f;
  short nf;
  FILE *idxf;
  FILE *statf = mix_parse (stream,&idxf,NIL,LONGT);
  unsigned long seq = mix_modseq (LOCAL->statusseq);
				/* find first free key */
  for (ffkey = 0; (ffkey < NUSERFLAGS) && stream->user_flags[ffkey]; ++ffkey);
				/* parse sequence and flags */
  if (((flags & ST_UID) ? mail_uid_sequence (stream,sequence) :
       mail_sequence (stream,sequence)) &&
      ((f = mail_parse_flags (stream,flag,&uf)) || uf)) {
				/* alter flags */
    for (i = 1,nf = (flags & ST_SET) ? T : NIL; i <= stream->nmsgs; i++)
      if ((elt = mail_elt (stream,i))->sequence) {
	struct {		/* old flags */
	  unsigned int seen : 1;
	  unsigned int deleted : 1;
	  unsigned int flagged : 1;
	  unsigned int answered : 1;
	  unsigned int draft : 1;
	  unsigned long user_flags;
	} old;
	old.seen = elt->seen; old.deleted = elt->deleted;
	old.flagged = elt->flagged; old.answered = elt->answered;
	old.draft = elt->draft; old.user_flags = elt->user_flags;
	if (f&fSEEN) elt->seen = nf;
	if (f&fDELETED) elt->deleted = nf;
	if (f&fFLAGGED) elt->flagged = nf;
	if (f&fANSWERED) elt->answered = nf;
	if (f&fDRAFT) elt->draft = nf;
				/* user flags */
	if (flags & ST_SET) elt->user_flags |= uf;
	else elt->user_flags &= ~uf;
	if ((old.seen != elt->seen) || (old.deleted != elt->deleted) ||
	    (old.flagged != elt->flagged) ||
	    (old.answered != elt->answered) || (old.draft != elt->draft) ||
	    (old.user_flags != elt->user_flags)) {
	  if (!stream->rdonly) elt->private.mod = LOCAL->statusseq = seq;
	  MM_FLAGS (stream,elt->msgno);
	}
      }
				/* update status file after change */
    if (statf && (seq == LOCAL->statusseq))
      mix_status_update (stream,statf,NIL);
				/* update metadata if created a keyword */
    if ((ffkey < NUSERFLAGS) && stream->user_flags[ffkey] &&
	!mix_meta_update (stream))
      MM_LOG ("Error updating mix metadata after keyword creation",ERROR);
  }
  if (statf) fclose (statf);	/* release status file if still open */
  if (idxf) fclose (idxf);	/* release index file */
}

/* MIX mail sort messages
 * Accepts: mail stream
 *	    character set
 *	    search program
 *	    sort program
 *	    option flags
 * Returns: vector of sorted message sequences or NIL if error
 */

unsigned long *mix_sort (MAILSTREAM *stream,char *charset,SEARCHPGM *spg,
			 SORTPGM *pgm,long flags)
{
  unsigned long *ret;
  FILE *sortcache = mix_sortcache_open (stream);
  ret = mail_sort_msgs (stream,charset,spg,pgm,flags);
  mix_sortcache_update (stream,&sortcache);
  return ret;
}


/* MIX mail thread messages
 * Accepts: mail stream
 *	    thread type
 *	    character set
 *	    search program
 *	    option flags
 * Returns: thread node tree or NIL if error
 */

THREADNODE *mix_thread (MAILSTREAM *stream,char *type,char *charset,
			SEARCHPGM *spg,long flags)
{
  THREADNODE *ret;
  FILE *sortcache = mix_sortcache_open (stream);
  ret = mail_thread_msgs (stream,type,charset,spg,flags,mail_sort_msgs);
  mix_sortcache_update (stream,&sortcache);
  return ret;
}

/* MIX mail ping mailbox
 * Accepts: MAIL stream
 * Returns: T if stream alive, else NIL
 */

static int snarfing = 0;	/* lock against recursive snarfing */

long mix_ping (MAILSTREAM *stream)
{
  FILE *idxf,*statf;
  struct stat sbuf;
  STRING msg;
  MESSAGECACHE *elt;
  int mfd,ifd,sfd;
  unsigned long i,msglen;
  char *message,date[MAILTMPLEN],flags[MAILTMPLEN];
  MAILSTREAM *sysibx = NIL;
  long ret = NIL;
  long snarfok = LONGT;
				/* time to snarf? */
  if (stream->inbox && !stream->rdonly && !snarfing &&
      (time (0) >= (LOCAL->lastsnarf +
		    (time_t) mail_parameters (NIL,GET_SNARFINTERVAL,NIL)))) {
    appenduid_t au = (appenduid_t) mail_parameters (NIL,GET_APPENDUID,NIL);
    copyuid_t cu = (copyuid_t) mail_parameters (NIL,GET_COPYUID,NIL);
    MM_CRITICAL (stream);	/* go critical */
    snarfing = T;		/* don't recursively snarf */
				/* disable APPENDUID/COPYUID callbacks */
    mail_parameters (NIL,SET_APPENDUID,NIL);
    mail_parameters (NIL,SET_COPYUID,NIL);
				/* sizes match and anything in sysinbox? */
    if (!stat (sysinbox (),&sbuf) && ((sbuf.st_mode & S_IFMT) == S_IFREG) &&
	sbuf.st_size &&	(sysibx = mail_open (sysibx,sysinbox (),OP_SILENT)) &&
	!sysibx->rdonly && sysibx->nmsgs) {
				/* for each message in sysibx mailbox */
      for (i = 1; snarfok && (i <= sysibx->nmsgs); ++i)
	if (!(elt = mail_elt (sysibx,i))->deleted &&
	    (message = mail_fetch_message (sysibx,i,&msglen,FT_PEEK)) &&
	    msglen) {
	  mail_date (date,elt);	/* make internal date string */
				/* make flag string */
	  flags[0] = flags[1] = '\0';
	  if (elt->seen) strcat (flags," \\Seen");
	  if (elt->flagged) strcat (flags," \\Flagged");
	  if (elt->answered) strcat (flags," \\Answered");
	  if (elt->draft) strcat (flags," \\Draft");
	  flags[0] = '(';
	  strcat (flags,")");
	  INIT (&msg,mail_string,message,msglen);
	  if (snarfok = mail_append_full (stream,"INBOX",flags,date,&msg)) {
	    char sequence[15];
	    sprintf (sequence,"%lu",i);
	    mail_flag (sysibx,sequence,"\\Deleted",ST_SET);
	  }
	}

				/* now expunge all those messages */
      if (snarfok) mail_expunge (sysibx);
      else {
	sprintf (LOCAL->buf,"Can't copy new mail at message: %lu",i - 1);
	MM_LOG (LOCAL->buf,WARN);
      }
    }
    if (sysibx) mail_close (sysibx);
				/* reenable APPENDUID/COPYUID */
    mail_parameters (NIL,SET_APPENDUID,(void *) au);
    mail_parameters (NIL,SET_COPYUID,(void *) cu);
    snarfing = NIL;		/* no longer snarfing */
    MM_NOCRITICAL (stream);	/* release critical */
    LOCAL->lastsnarf = time (0);/* note time of last snarf */
  }
				/* expunging OK if global flag set */
  if (mail_parameters (NIL,GET_EXPUNGEATPING,NIL)) LOCAL->expok = T;
				/* process metadata/index/status */
  if (statf = mix_parse (stream,&idxf,LONGT,
			 (LOCAL->internal ? NIL : LONGT))) {
    fclose (statf);		/* just close the status file */
    ret = LONGT;		/* declare success */
  }
  if (idxf) fclose (idxf);	/* release index file */
  LOCAL->expok = NIL;		/* expunge no longer OK */
  if (!ret) mix_abort (stream);	/* murdelyze stream if ping fails */
  return ret;
}


/* MIX mail checkpoint mailbox (burp only)
 * Accepts: MAIL stream
 */

void mix_check (MAILSTREAM *stream)
{
  if (stream->rdonly)		/* won't do on readonly files! */
    MM_LOG ("Checkpoint ignored on readonly mailbox",NIL);
				/* do burp-only expunge action */
  if (mix_expunge (stream,"",NIL)) MM_LOG ("Check completed",(long) NIL);
}

/* MIX mail expunge mailbox
 * Accepts: MAIL stream
 *	    sequence to expunge if non-NIL, empty string for burp only
 *	    expunge options
 * Returns: T on success, NIL if failure
 */

long mix_expunge (MAILSTREAM *stream,char *sequence,long options)
{
  FILE *idxf = NIL;
  FILE *statf = NIL;
  MESSAGECACHE *elt;
  int ifd,sfd;
  long ret;
  unsigned long i;
  unsigned long nexp = 0;
  unsigned long reclaimed = 0;
  int burponly = (sequence && !*sequence);
  LOCAL->expok = T;		/* expunge during ping is OK */
  if (!(ret = burponly || !sequence ||
	((options & EX_UID) ?
	 mail_uid_sequence (stream,sequence) :
	 mail_sequence (stream,sequence))) || stream->rdonly);
				/* read index and open status exclusive */
  else if (statf = mix_parse (stream,&idxf,LONGT,
			      LOCAL->internal ? NIL : LONGT)) {
				/* expunge unless just burping */
    if (!burponly) for (i = 1; i <= stream->nmsgs;) {
      elt = mail_elt (stream,i);/* need to expunge this message? */
      if (sequence ? elt->sequence : elt->deleted) {
	++nexp;			/* yes, make it so */
	mail_expunged (stream,i);
      }
      else ++i;		       /* otherwise advance to next message */
    }

				/* burp if can get exclusive access */
    if (!flock (LOCAL->mfd,LOCK_EX|LOCK_NB)) {
      void *a;
      struct direct **names = NIL;
      long nfiles = scandir (stream->mailbox,&names,mix_select,mix_msgfsort);
      if (nfiles > 0) {		/* if have message files */
	MIXBURP *burp,*cur;
				/* initialize burp list */
	for (i = 0, burp = cur = NIL; i < nfiles; ++i) {
	  MIXBURP *nxt = (MIXBURP *) memset (fs_get (sizeof (MIXBURP)),0,
					     sizeof (MIXBURP));
				/* another file found */
	  if (cur) cur = cur->next = nxt;
	  else cur = burp = nxt;
	  cur->name = names[i]->d_name;
	  cur->fileno = strtoul (cur->name + sizeof (MIXNAME) - 1,NIL,16);
	  cur->tail = &cur->set;
	  fs_give ((void **) &names[i]);
	}
				/* now load ranges */
	for (i = 1, cur = burp; ret && (i <= stream->nmsgs); i++) {
				/* is this message in current set? */
	  elt = mail_elt (stream,i);
	  if (cur && (elt->private.spare.data != cur->fileno)) {
				/* restart if necessary */
	    if (elt->private.spare.data < cur->fileno) cur = burp;
				/* hunt for appropriate mailbox */
	    while (cur && (elt->private.spare.data > cur->fileno))
	      cur = cur->next;
				/* ought to have found it now... */
	    if (cur && (elt->private.spare.data != cur->fileno)) cur = NIL;
	  }
				/* if found, add to set */
	  if (cur) ret = mix_addset (&cur->tail,elt->private.special.offset,
				     elt->private.msg.header.offset +
				     elt->rfc822_size);
	  else {		/* uh-oh */
	    sprintf (LOCAL->buf,"Can't locate mix message file %.08lx",
		     elt->private.spare.data);
	    MM_LOG (LOCAL->buf,ERROR);
	    ret = NIL;
	  }
	}
	if (ret) 		/* if no errors, burp all files */
	  for (cur = burp; ret && cur; cur = cur->next) {
				/* if non-empty, burp it */
	    if (cur->set.last) ret = mix_burp (stream,cur,&reclaimed);
				/* empty, delete it unless new msg file */
	    else if (mix_file_data (LOCAL->buf,stream->mailbox,cur->fileno) &&
		     ((cur->fileno == LOCAL->newmsg) ?
		      truncate (LOCAL->buf,0) : unlink (LOCAL->buf))) {
	      sprintf (LOCAL->buf,
		       "Can't delete empty message file %.80s: %.80s",
		       cur->name,strerror (errno));
	      MM_LOG (LOCAL->buf,WARN);
	    }
	  }
      }
      else MM_LOG ("No mix message files found during expunge",WARN);
				/* free directory list */
      if (a = (void *) names) fs_give ((void **) &a);
    }

				/* either way, re-acquire shared lock */
    if (flock (LOCAL->mfd,LOCK_SH|LOCK_NB))
      fatal ("Unable to re-acquire metadata shared lock!");
    /* Do this step even if ret is NIL (meaning some burp problem)! */
    if (nexp || reclaimed) {	/* rewrite index and status if changed */
      LOCAL->indexseq = mix_modseq (LOCAL->indexseq);
      if (mix_index_update (stream,idxf,NIL)) {
	LOCAL->statusseq = mix_modseq (LOCAL->statusseq);
				/* set failure if update fails */
	ret = mix_status_update (stream,statf,NIL);
      }
    }
  }
  if (statf) fclose (statf);	/* close status if still open */
  if (idxf) fclose (idxf);	/* close index if still open */
  LOCAL->expok = NIL;		/* cancel expok */
  if (ret) {			/* only if success */
    char *s = NIL;
    if (nexp) sprintf (s = LOCAL->buf,"Expunged %lu messages",nexp);
    else if (reclaimed)
      sprintf (s=LOCAL->buf,"Reclaimed %lu bytes of expunged space",reclaimed);
    else if (!burponly)
      s = stream->rdonly ? "Expunge ignored on readonly mailbox" :
	   "No messages deleted, so no update needed";
    if (s) MM_LOG (s,(long) NIL);
  }
  return ret;
}