mmdf.c

这是用C编写IMAP源代码

				     elt->private.msg.header.text.size) + 1);
    }
				/* read message */
    read (LOCAL->fd,LOCAL->buf,elt->private.msg.header.text.size);
				/* got text, tie off string */
    LOCAL->buf[*length = elt->private.msg.header.text.size] = '\0';
				/* squeeze out CRs (in case from PC) */
    for (s = t = LOCAL->buf,tl = LOCAL->buf + *length; t <= tl; t++)
      if ((*t != '\r') || (t[1] != '\n')) *s++ = *t;
				/* adjust length */
    LOCAL->buf[*length = s - LOCAL->buf - 1] = '\0';
  }
  else {			/* need to make a CRLF version */
    read (LOCAL->fd,s = (char *) fs_get (elt->private.msg.header.text.size+1),
	  elt->private.msg.header.text.size);
				/* tie off string, and convert to CRLF */
    s[elt->private.msg.header.text.size] = '\0';
    *length = strcrlfcpy (&LOCAL->buf,&LOCAL->buflen,s,
			  elt->private.msg.header.text.size);
    fs_give ((void **) &s);	/* free readin buffer */
  }
  *length = mail_filter (LOCAL->buf,*length,mmdf_hlines,FT_NOT);
  return LOCAL->buf;		/* return processed copy */
}

/* MMDF mail fetch message text
 * Accepts: MAIL stream
 *	    message # to fetch
 *	    pointer to returned stringstruct
 *	    option flags
 * Returns: T on success, NIL if failure
 */

long mmdf_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags)
{
  char *s;
  unsigned long i;
  MESSAGECACHE *elt;
				/* UID call "impossible" */
  if (flags & FT_UID) return NIL;
  elt = mail_elt (stream,msgno);/* get cache element */
				/* if message not seen */
  if (!(flags & FT_PEEK) && !elt->seen) {
				/* mark message seen and dirty */
    elt->seen = elt->private.dirty = LOCAL->dirty = T;
    MM_FLAGS (stream,msgno);
  }
  s = mmdf_text_work (stream,elt,&i,flags);
  INIT (bs,mail_string,s,i);	/* set up stringstruct */
  return T;			/* success */
}

/* MMDF mail fetch message text worker routine
 * Accepts: MAIL stream
 *	    message cache element
 *	    pointer to returned header text length
 *	    option flags
 */

char *mmdf_text_work (MAILSTREAM *stream,MESSAGECACHE *elt,
		      unsigned long *length,long flags)
{
  FDDATA d;
  STRING bs;
  unsigned char *s,*t,*tl,tmp[CHUNK];
				/* go to text position */
  lseek (LOCAL->fd,elt->private.special.offset +
	 elt->private.msg.text.offset,L_SET);
  if (flags & FT_INTERNAL) {	/* initial data OK? */
    if (elt->private.msg.text.text.size > LOCAL->buflen) {
      fs_give ((void **) &LOCAL->buf);
      LOCAL->buf = (char *) fs_get ((LOCAL->buflen =
				     elt->private.msg.text.text.size) + 1);
    }
				/* read message */
    read (LOCAL->fd,LOCAL->buf,elt->private.msg.text.text.size);
				/* got text, tie off string */
    LOCAL->buf[*length = elt->private.msg.text.text.size] = '\0';
				/* squeeze out CRs (in case from PC) */
    for (s = t = LOCAL->buf,tl = LOCAL->buf + *length; t <= tl; t++)
      if ((*t != '\r') || (t[1] != '\n')) *s++ = *t;
				/* adjust length */
    LOCAL->buf[*length = s - LOCAL->buf - 1] = '\0';
    return LOCAL->buf;
  }

				/* have it cached already? */
  if (elt->private.uid != LOCAL->uid) {
				/* not cached, cache it now */
    LOCAL->uid = elt->private.uid;
				/* is buffer big enough? */
    if (elt->rfc822_size > LOCAL->text.size) {
      /* excessively conservative, but the right thing is too hard to do */
      fs_give ((void **) &LOCAL->text.data);
      LOCAL->text.data = (unsigned char *)
	fs_get ((LOCAL->text.size = elt->rfc822_size) + 1);
    }
    d.fd = LOCAL->fd;		/* yes, set up file descriptor */
    d.pos = elt->private.special.offset + elt->private.msg.text.offset;
    d.chunk = tmp;		/* initial buffer chunk */
    d.chunksize = CHUNK;	/* file chunk size */
    INIT (&bs,fd_string,&d,elt->private.msg.text.text.size);
    for (s = (char *) LOCAL->text.data; SIZE (&bs);) switch (CHR (&bs)) {
    case '\r':			/* carriage return seen */
      *s++ = SNX (&bs);		/* copy it and any succeeding LF */
      if (SIZE (&bs) && (CHR (&bs) == '\n')) *s++ = SNX (&bs);
      break;
    case '\n':
      *s++ = '\r';		/* insert a CR */
    default:
      *s++ = SNX (&bs);		/* copy characters */
    }
    *s = '\0';			/* tie off buffer */
				/* calculate length of cached data */
    LOCAL->textlen = s - LOCAL->text.data;
  }
  *length = LOCAL->textlen;	/* return from cache */
  return (char *) LOCAL->text.data;
}

/* MMDF per-message modify flag
 * Accepts: MAIL stream
 *	    message cache element
 */

void mmdf_flagmsg (MAILSTREAM *stream,MESSAGECACHE *elt)
{
				/* only after finishing */
  if (elt->valid) elt->private.dirty = LOCAL->dirty = T;
}


/* MMDF mail ping mailbox
 * Accepts: MAIL stream
 * Returns: T if stream alive, else NIL
 */

long mmdf_ping (MAILSTREAM *stream)
{
  DOTLOCK lock;
  struct stat sbuf;
  long reparse;
				/* big no-op if not readwrite */
  if (LOCAL && (LOCAL->ld >= 0) && !stream->lock) {
    if (stream->rdonly) {	/* does he want to give up readwrite? */
				/* checkpoint if we changed something */
      if (LOCAL->dirty) mmdf_check (stream);
      flock (LOCAL->ld,LOCK_UN);/* release readwrite lock */
      close (LOCAL->ld);	/* close the readwrite lock file */
      LOCAL->ld = -1;		/* no more readwrite lock fd */
      unlink (LOCAL->lname);	/* delete the readwrite lock file */
    }
    else {			/* see if need to reparse */
      if (!(reparse = (long) mail_parameters (NIL,GET_NETFSSTATBUG,NIL))) {
				/* get current mailbox size */
	if (LOCAL->fd >= 0) fstat (LOCAL->fd,&sbuf);
	else stat (stream->mailbox,&sbuf);
	reparse = (sbuf.st_size != LOCAL->filesize);
      }
				/* parse if mailbox changed */
      if (reparse && mmdf_parse (stream,&lock,LOCK_SH)) {
				/* unlock mailbox */
	mmdf_unlock (LOCAL->fd,stream,&lock);
	mail_unlock (stream);	/* and stream */
				/* done with critical */
	MM_NOCRITICAL (stream);
      }
    }
  }
  return LOCAL ? LONGT : NIL;	/* return if still alive */
}

/* MMDF mail check mailbox
 * Accepts: MAIL stream
 */

void mmdf_check (MAILSTREAM *stream)
{
  DOTLOCK lock;
				/* parse and lock mailbox */
  if (LOCAL && (LOCAL->ld >= 0) && !stream->lock &&
      mmdf_parse (stream,&lock,LOCK_EX)) {
				/* any unsaved changes? */
    if (LOCAL->dirty && mmdf_rewrite (stream,NIL,&lock)) {
      if (!stream->silent) MM_LOG ("Checkpoint completed",NIL);
    }
				/* no checkpoint needed, just unlock */
    else mmdf_unlock (LOCAL->fd,stream,&lock);
    mail_unlock (stream);	/* unlock the stream */
    MM_NOCRITICAL (stream);	/* done with critical */
  }
}


/* MMDF mail expunge mailbox
 * Accepts: MAIL stream
 */

void mmdf_expunge (MAILSTREAM *stream)
{
  unsigned long i;
  DOTLOCK lock;
  char *msg = NIL;
				/* parse and lock mailbox */
  if (LOCAL && (LOCAL->ld >= 0) && !stream->lock &&
      mmdf_parse (stream,&lock,LOCK_EX)) {
				/* count expunged messages if not dirty */
    if (!LOCAL->dirty) for (i = 1; i <= stream->nmsgs; i++)
      if (mail_elt (stream,i)->deleted) LOCAL->dirty = T;
    if (!LOCAL->dirty) {	/* not dirty and no expunged messages */
      mmdf_unlock (LOCAL->fd,stream,&lock);
      msg = "No messages deleted, so no update needed";
    }
    else if (mmdf_rewrite (stream,&i,&lock)) {
      if (i) sprintf (msg = LOCAL->buf,"Expunged %lu messages",i);
      else msg = "Mailbox checkpointed, but no messages expunged";
    }
				/* rewrite failed */
    else mmdf_unlock (LOCAL->fd,stream,&lock);
    mail_unlock (stream);	/* unlock the stream */
    MM_NOCRITICAL (stream);	/* done with critical */
    if (msg && !stream->silent) MM_LOG (msg,NIL);
  }
  else if (!stream->silent)
    MM_LOG ("Expunge ignored on readonly mailbox",WARN);
}

/* MMDF mail copy message(s)
 * Accepts: MAIL stream
 *	    sequence
 *	    destination mailbox
 *	    copy options
 * Returns: T if copy successful, else NIL
 */

long mmdf_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options)
{
  struct stat sbuf;
  int fd;
  char *s,file[MAILTMPLEN];
  DOTLOCK lock;
  time_t tp[2];
  unsigned long i,j;
  MESSAGECACHE *elt;
  long ret = T;
  mailproxycopy_t pc =
    (mailproxycopy_t) mail_parameters (stream,GET_MAILPROXYCOPY,NIL);
  if (!((options & CP_UID) ? mail_uid_sequence (stream,sequence) :
	mail_sequence (stream,sequence))) return NIL;
				/* make sure valid mailbox */
  if (!mmdf_isvalid (mailbox,file)) switch (errno) {
  case ENOENT:			/* no such file? */
    if (!compare_cstring (mailbox,"INBOX")) {
      if (pc) return (*pc) (stream,sequence,mailbox,options);
      mmdf_create (NIL,"INBOX");/* create empty INBOX */
      break;
    }
    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 MMDF-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 MMDF-format mailbox: %.80s",mailbox);
    MM_LOG (LOCAL->buf,ERROR);
    return NIL;
  }
  LOCAL->buf[0] = '\0';
  MM_CRITICAL (stream);		/* go critical */
  if ((fd = mmdf_lock (dummy_file (file,mailbox),O_WRONLY|O_APPEND|O_CREAT,
		       S_IREAD|S_IWRITE,&lock,LOCK_EX)) < 0) {
    MM_NOCRITICAL (stream);	/* done with critical */
    sprintf (LOCAL->buf,"Can't open destination mailbox: %s",strerror (errno));
    MM_LOG (LOCAL->buf,ERROR);	/* log the error */
    return NIL;			/* failed */
  }
  fstat (fd,&sbuf);		/* get current file size */

				/* write all requested messages to mailbox */
  for (i = 1; ret && (i <= stream->nmsgs); i++)
    if ((elt = mail_elt (stream,i))->sequence) {
      lseek (LOCAL->fd,elt->private.special.offset,L_SET);
      read (LOCAL->fd,LOCAL->buf,elt->private.special.text.size);
      if (write (fd,LOCAL->buf,elt->private.special.text.size) < 0) ret = NIL;
      else {			/* internal header succeeded */
	s = mmdf_header (stream,i,&j,FT_INTERNAL);
				/* header size, sans trailing newline */
	if (j && (s[j - 2] == '\n')) j--;
	if (write (fd,s,j) < 0) ret = NIL;
	else {			/* message header succeeded */
	  j = mmdf_xstatus (stream,LOCAL->buf,elt,NIL);
	  if (write (fd,LOCAL->buf,j) < 0) ret = NIL;
	  else {		/* message status succeeded */
	    s = mmdf_text_work (stream,elt,&j,FT_INTERNAL);
	    if ((write (fd,s,j) < 0) || (write (fd,mmdfhdr,MMDFHDRLEN) < 0))
	      ret = NIL;
	  }
	}
      }
    }
  if (!ret || fsync (fd)) {	/* force out the update */
    sprintf (LOCAL->buf,"Message copy failed: %s",strerror (errno));
    ftruncate (fd,sbuf.st_size);
    ret = NIL;
  }
  tp[1] = time (0);		/* set mtime to now */
  if (ret) tp[0] = tp[1] - 1;	/* set atime to now-1 if successful copy */
  else tp[0] =			/* else preserve \Marked status */
	 ((sbuf.st_ctime > sbuf.st_atime) || (sbuf.st_mtime > sbuf.st_atime)) ?
	 sbuf.st_atime : tp[1];
  utime (file,tp);		/* set the times */
  mmdf_unlock (fd,NIL,&lock);	/* unlock and close mailbox */
  MM_NOCRITICAL (stream);	/* release critical */
				/* log the error */
  if (!ret) MM_LOG (LOCAL->buf,ERROR);
				/* delete if requested message */
  else if (options & CP_MOVE) for (i = 1; i <= stream->nmsgs; i++)
    if ((elt = mail_elt (stream,i))->sequence)
      elt->deleted = elt->private.dirty = LOCAL->dirty = T;
  return ret;
}

/* MMDF mail append message from stringstruct
 * Accepts: MAIL stream
 *	    destination mailbox
 *	    append callback
 *	    data for callback
 * Returns: T if append successful, else NIL
 */

#define BUFLEN 8*MAILTMPLEN

long mmdf_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data)
{
  struct stat sbuf;
  int fd;
  unsigned long i,j;
  char *flags,*date,buf[BUFLEN],tmp[MAILTMPLEN],file[MAILTMPLEN];
  time_t tp[2];
  FILE *sf,*df;
  MESSAGECACHE elt;
  DOTLOCK lock;
  STRING *message;
  long ret = LONGT;
				/* default stream to prototype */
  if (!stream) {		/* stream specified? */
    stream = &mmdfproto;	/* no, default stream to prototype */
    for (i = 0; i < NUSERFLAGS && stream->user_flags[i]; ++i)
      fs_give ((void **) &stream->user_flags[i]);
    stream->kwd_create = T;	/* allow new flags */
  }
				/* make sure valid mailbox */
  if (!mmdf_valid (mailbox)) switch (errno) {
  case ENOENT:			/* no such file? */
    if (!compare_cstring (mailbox,"INBOX")) {
      mmdf_create (NIL,"INBOX");/* create empty INBOX */
      break;
    }
    MM_NOTIFY (stream,"[TRYCREATE] Must create mailbox before append",NIL);
    return NIL;
  case 0:			/* merely empty file? */
    break;
  case EINVAL:
    sprintf (tmp,"Invalid MMDF-format mailbox name: %.80s",mailbox);
    MM_LOG (tmp,ERROR);
    return NIL;
  default:
    sprintf (tmp,"Not a MMDF-format mailbox: %.80s",mailbox);