tenex.c

这是用C编写IMAP源代码

 * 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 snarf messages from system inbox
 * Accepts: MAIL stream
 */

void tenex_snarf (MAILSTREAM *stream)
{
  unsigned long i = 0;
  unsigned long j,r,hdrlen,txtlen;
  struct stat sbuf;
  char *hdr,*txt,lock[MAILTMPLEN],tmp[MAILTMPLEN];
  MESSAGECACHE *elt;
  MAILSTREAM *sysibx = NIL;
  int ld;
				/* give up if can't get exclusive permission */
  if ((time (0) >= (LOCAL->lastsnarf +
		    (long) mail_parameters (NIL,GET_SNARFINTERVAL,NIL))) &&
      strcmp (sysinbox (),stream->mailbox) &&
      ((ld = lockfd (LOCAL->fd,lock,LOCK_EX)) >= 0)) {
    MM_CRITICAL (stream);	/* go critical */
				/* sizes match and anything in sysinbox? */
    if (!stat (sysinbox (),&sbuf) && sbuf.st_size &&
	!fstat (LOCAL->fd,&sbuf) && (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 */
	hdr = cpystr (mail_fetchheader_full(sysibx,i,NIL,&hdrlen,FT_INTERNAL));
	txt = mail_fetchtext_full (sysibx,i,&txtlen,FT_INTERNAL|FT_PEEK);
				/* if have a message */
	if (j = hdrlen + txtlen) {
				/* calculate header line */
	  mail_date (LOCAL->buf,elt = mail_elt (sysibx,i));
	  sprintf (LOCAL->buf + strlen (LOCAL->buf),
		   ",%lu;0000000000%02o\n",j,(unsigned)
		   ((fSEEN * elt->seen) + (fDELETED * elt->deleted) +
		    (fFLAGGED * elt->flagged) + (fANSWERED * elt->answered) +
		    (fDRAFT * elt->draft)));
				/* copy message */
	  if ((write (LOCAL->fd,LOCAL->buf,strlen (LOCAL->buf)) < 0) ||
	      (write (LOCAL->fd,hdr,hdrlen) < 0) ||
	      (write (LOCAL->fd,txt,txtlen) < 0)) r = 0;
	}
	fs_give ((void **) &hdr);
      }

				/* make sure all the updates take */
      if (fsync (LOCAL->fd)) r = 0;
      if (r) {			/* delete all the messages we copied */
	if (r == 1) strcpy (tmp,"1");
	else sprintf (tmp,"1:%lu",r);
	mail_flag (sysibx,tmp,"\\Deleted",ST_SET);
	mail_expunge (sysibx);	/* now expunge all those messages */
      }
      else {
	sprintf (LOCAL->buf,"Can't copy new mail: %s",strerror (errno));
	MM_LOG (LOCAL->buf,ERROR);
	ftruncate (LOCAL->fd,sbuf.st_size);
      }
      fstat (LOCAL->fd,&sbuf);	/* yes, get current file size */
      LOCAL->filetime = sbuf.st_mtime;
    }
    if (sysibx) mail_close (sysibx);
    MM_NOCRITICAL (stream);	/* release critical */
    unlockfd (ld,lock);		/* release exclusive parse/append permission */
    LOCAL->lastsnarf = time (0);/* note time of last snarf */
  }
}

/* Tenex mail expunge mailbox
 * Accepts: MAIL stream
 */

void tenex_expunge (MAILSTREAM *stream)
{
  time_t tp[2];
  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;
  blocknotify_t bn = (blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
				/* do nothing if stream dead */
  if (!tenex_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 exclusive parse/append permission */
  if ((ld = lockfd (LOCAL->fd,lock,LOCK_EX)) < 0) {
    MM_LOG ("Unable to lock expunge mailbox",ERROR);
    return;
  }
				/* make sure see any newly-arrived messages */
  if (!tenex_parse (stream)) return;
				/* get exclusive access */
  if (flock (LOCAL->fd,LOCK_EX|LOCK_NB)) {
    (*bn) (BLOCK_FILELOCK,NIL);
    flock (LOCAL->fd,LOCK_SH);	/* recover previous lock */
    (*bn) (BLOCK_NONE,NIL);
    MM_LOG ("Can't expunge because mailbox is in use by another process",
	      ERROR);
    unlockfd (ld,lock);		/* release exclusive parse/append permission */
    return;
  }

  MM_CRITICAL (stream);		/* go critical */
  recent = stream->recent;	/* get recent now that pinged and locked */
  while (i <= stream->nmsgs) {	/* for each message */
    elt = tenex_elt (stream,i);	/* get cache element */
				/* number of bytes to smash or preserve */
    k = elt->private.special.text.size + tenex_size (stream,i);
    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 */
				/* 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 */
	lseek (LOCAL->fd,pos,L_SET);
	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 */
  tp[1] = LOCAL->filetime = sbuf.st_mtime;
  tp[0] = time (0);		/* reset atime to now */
  utime (stream->mailbox,tp);
  MM_NOCRITICAL (stream);	/* release critical */
				/* notify upper level of new mailbox size */
  mail_exists (stream,stream->nmsgs);
  mail_recent (stream,recent);
  (*bn) (BLOCK_FILELOCK,NIL);
  flock (LOCAL->fd,LOCK_SH);	/* allow sharers again */
  (*bn) (BLOCK_NONE,NIL);
  unlockfd (ld,lock);		/* release exclusive parse/append permission */
}

/* 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;
  time_t tp[2];
  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,LOCAL->buf)) 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:
    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(tenex_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 exclusive parse/append permission */
  if ((ld = lockfd (fd,lock,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 */
    }
				/* make sure all the updates take */
  if (!(ret && (ret = !fsync (fd)))) {
    sprintf (LOCAL->buf,"Unable to write message: %s",strerror (errno));
    MM_LOG (LOCAL->buf,ERROR);
    ftruncate (fd,sbuf.st_size);
  }
  if (ret) tp[0] = time (0) - 1;/* set atime to now-1 if successful copy */
				/* else preserve \Marked status */
  else tp[0] = (sbuf.st_ctime > sbuf.st_atime) ? sbuf.st_atime : time(0);
  tp[1] = sbuf.st_mtime;	/* preserve mtime */
  utime (file,tp);		/* set the times */
  close (fd);			/* close the file */
  unlockfd (ld,lock);		/* release exclusive parse/append permission */
  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 */
      tp[1] = LOCAL->filetime = sbuf.st_mtime;
      tp[0] = time (0);		/* make sure atime remains greater */
      utime (stream->mailbox,tp);
    }
  }
  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];
  time_t tp[2];
  FILE *df;
  MESSAGECACHE elt;
  long f;
  unsigned long i,j,uf,size;
  STRING *message;
  long ret = LONGT;
				/* default stream to prototype */
  if (!stream) stream = user_flags (&tenexproto);
				/* make sure valid mailbox */
  if (!tenex_isvalid (mailbox,tmp)) switch (errno) {
  case ENOENT:			/* no such file? */
    if (!compare_cstring (mailbox,"INBOX")) dummy_create (NIL,"mail.txt");
    else {
      MM_NOTIFY (stream,"[TRYCREATE] Must create mailbox before append",NIL);
      return NIL;
    }
				/* falls through */
  case 0:			/* merely empty file? */
    break;
  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 (!MM_APPEND (af) (stream,data,&flags,&date,&message)) return NIL;

				/* open destination mailbox */
  if (((fd = open (tenex_file (file,mailbox),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 ((ld = lockfd (fd,lock,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;