mbx.c

广泛使用的邮件服务器！同时

/* ========================================================================
 * 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:	MBX mail routines
 *
 * Author:	Mark Crispin
 *		Networks and Distributed Computing
 *		Computing & Communications
 *		University of Washington
 *		Administration Building, AG-44
 *		Seattle, WA  98195
 *		Internet: [e-mail]
 *
 * Date:	3 October 1995
 * Last Edited:	11 October 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.
 */

#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 "misc.h"
#include "dummy.h"
#include "fdstring.h"


/* Build parameters */

#define HDRSIZE 2048


/* Kludge to make Cygwin happy */

#ifndef O_BINARY
#define O_BINARY 0
#endif

/* MBX I/O stream local data */
	
typedef struct mbx_local {
  unsigned int flagcheck: 1;	/* if ping should sweep for flags */
  unsigned int expok: 1;	/* if expunging OK in ping */
  unsigned int expunged : 1;	/* if one or more expunged messages */
  int fd;			/* file descriptor for I/O */
  int ld;			/* lock file descriptor */
  int ffuserflag;		/* first free user flag */
  off_t filesize;		/* file size parsed */
  time_t filetime;		/* last file time */
  time_t lastsnarf;		/* last snarf time */
  unsigned long lastpid;	/* PID of last writer */
  unsigned char *buf;		/* temporary buffer */
  unsigned long buflen;		/* current size of temporary buffer */
  char lock[MAILTMPLEN];	/* buffer to write lock name */
} MBXLOCAL;


/* Convenient access to local data */

#define LOCAL ((MBXLOCAL *) stream->local)

/* Function prototypes */

DRIVER *mbx_valid (char *name);
int mbx_isvalid (MAILSTREAM **stream,char *name,char *tmp,int *ld,char *lock,
		 long flags);
void *mbx_parameters (long function,void *value);
void mbx_scan (MAILSTREAM *stream,char *ref,char *pat,char *contents);
void mbx_list (MAILSTREAM *stream,char *ref,char *pat);
void mbx_lsub (MAILSTREAM *stream,char *ref,char *pat);
long mbx_create (MAILSTREAM *stream,char *mailbox);
long mbx_delete (MAILSTREAM *stream,char *mailbox);
long mbx_rename (MAILSTREAM *stream,char *old,char *newname);
long mbx_status (MAILSTREAM *stream,char *mbx,long flags);
MAILSTREAM *mbx_open (MAILSTREAM *stream);
void mbx_close (MAILSTREAM *stream,long options);
void mbx_abort (MAILSTREAM *stream);
void mbx_flags (MAILSTREAM *stream,char *sequence,long flags);
char *mbx_header (MAILSTREAM *stream,unsigned long msgno,unsigned long *length,
		  long flags);
long mbx_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags);
void mbx_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags);
void mbx_flagmsg (MAILSTREAM *stream,MESSAGECACHE *elt);
long mbx_ping (MAILSTREAM *stream);
void mbx_check (MAILSTREAM *stream);
long mbx_expunge (MAILSTREAM *stream,char *sequence,long options);
void mbx_snarf (MAILSTREAM *stream);
long mbx_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options);
long mbx_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data);

char *mbx_file (char *dst,char *name);
long mbx_parse (MAILSTREAM *stream);
MESSAGECACHE *mbx_elt (MAILSTREAM *stream,unsigned long msgno,long expok);
unsigned long mbx_read_flags (MAILSTREAM *stream,MESSAGECACHE *elt);
void mbx_update_header (MAILSTREAM *stream);
void mbx_update_status (MAILSTREAM *stream,unsigned long msgno,long flags);
unsigned long mbx_hdrpos (MAILSTREAM *stream,unsigned long msgno,
			  unsigned long *size,char **hdr);
unsigned long mbx_rewrite (MAILSTREAM *stream,unsigned long *reclaimed,
			   long flags);
long mbx_flaglock (MAILSTREAM *stream);

/* MBX mail routines */


/* Driver dispatch used by MAIL */

DRIVER mbxdriver = {
  "mbx",			/* driver name */
  DR_LOCAL|DR_MAIL|DR_CRLF|DR_LOCKING,
				/* 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 */
  mbx_status,			/* status of mailbox */
  mbx_open,			/* open mailbox */
  mbx_close,			/* close mailbox */
  mbx_flags,			/* fetch message "fast" attributes */
  mbx_flags,			/* fetch message flags */
  NIL,				/* fetch overview */
  NIL,				/* fetch message envelopes */
  mbx_header,			/* fetch message header */
  mbx_text,			/* fetch message body */
  NIL,				/* fetch partial message text */
  NIL,				/* unique identifier */
  NIL,				/* message number */
  mbx_flag,			/* modify flags */
  mbx_flagmsg,			/* per-message modify flags */
  NIL,				/* search for message based on criteria */
  NIL,				/* sort messages */
  NIL,				/* thread messages */
  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 */
  NIL				/* 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];
  int fd = mbx_isvalid (NIL,name,tmp,NIL,NIL,NIL);
  if (fd < 0) return NIL;
  close (fd);			/* don't need the fd now */
  return &mbxdriver;
}


/* MBX mail test for valid mailbox
 * Accepts: returned stream with valid mailbox keywords
 *	    mailbox name
 *	    scratch buffer
 *	    returned lock fd
 *	    returned lock name
 *	    RW flags or NIL for readonly
 * Returns: file descriptor if valid, NIL otherwise
 */

#define MBXISVALIDNOUID 0x1	/* RW, don't do UID action */
#define MBXISVALIDUID 0x2	/* RW, do UID action */

int mbx_isvalid (MAILSTREAM **stream,char *name,char *tmp,int *ld,char *lock,
		 long flags)
{
  int fd,upd;
  int ret = -1;
  unsigned long i;
  long j,k;
  off_t pos;
  char c,*s,*t,hdr[HDRSIZE];
  struct stat sbuf;
  time_t tp[2];
  int error = EINVAL;		/* assume invalid argument */
  if (ld) *ld = -1;		/* initially no lock */
  if ((s = mbx_file (tmp,name)) && !stat (s,&sbuf) &&
      ((fd = open (tmp,(flags ? O_RDWR : O_RDONLY)|O_BINARY,NIL)) >= 0)) {
    error = -1;			/* bogus format */
		/* I love cretinous C compilers -- don't you? */
    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 (c = 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 = fd;		/* mbx format */

	    if (stream) {	/* lock if making mini-stream */
	      if (flock (fd,LOCK_SH) ||
		  (flags && ((*ld = lockfd (fd,lock,LOCK_EX)) < 0))) ret = -1;
				/* reread data now that locked */
	      else if (lseek (fd,0,L_SET) ||
		       (read (fd,hdr,HDRSIZE) != HDRSIZE)) ret = -1;
	      else {
		*stream = (MAILSTREAM *) memset (fs_get (sizeof (MAILSTREAM)),
						 0,sizeof (MAILSTREAM));
		hdr[15] = '\0';	/* tie off UIDVALIDITY */
		(*stream)->uid_validity = strtoul (hdr+7,NIL,16);
		hdr[15] = c;	/* now get UIDLAST */
		(*stream)->uid_last = strtoul (hdr+15,NIL,16);
				/* parse user flags */
		for (i = 0, s = hdr + 25;
		     (i < NUSERFLAGS) && (t = strchr (s,'\015')) && (t - s);
		     i++, s = t + 2) {
		  *t = '\0';	/* tie off flag */
		  if (strlen (s) <= MAXUSERFLAG)
		    (*stream)->user_flags[i] = cpystr (s);
		}
				/* make sure have true UIDLAST */
		if (flags & MBXISVALIDUID) {
		  for (upd = NIL,pos = 2048, k = 0; pos < sbuf.st_size;
		       pos += (j + k)) {
				/* read header for this message */
		    lseek (fd,pos,L_SET);
		    if ((j = read (fd,hdr,64)) >= 0) {
		      hdr[j] = '\0';
		      if ((s = strchr (hdr,'\015')) && (s[1] == '\012')) {
			*s = '\0';
			k = s + 2 - hdr;
			if ((s = strchr (hdr,',')) &&
			    (j = strtol (s+1,&s,10)) && (*s == ';') &&
			    (s = strchr (s+1,'-'))) {
				/* get UID if there is any */
			  i = strtoul (++s,&t,16);
			  if (!*t && (t == (s + 8)) &&
			      (i <= (*stream)->uid_last)) {
			    if (!i) {
			      lseek (fd,pos + s - hdr,L_SET);
			      sprintf (hdr,"%08lx",++(*stream)->uid_last);
			      write (fd,hdr,8);
			      upd = T;
			    }
			    continue;
			  }
			}
		      }
		      ret = -1;	/* error, give up */
		      *stream = mail_close (*stream);
		      pos = sbuf.st_size + 1;
		      j = k = 0;
		    }
		  }

		  if (upd) {	/* need to update hdr with new UIDLAST? */
		    lseek (fd,15,L_SET);
		    sprintf (hdr,"%08lx",(*stream)->uid_last);
		    write (fd,hdr,8);
		  }
		}
	      }
	    }
	  }
    if (ret != fd) close (fd);	/* close the file */
    else lseek (fd,0,L_SET);	/* else rewind to start */
				/* \Marked status? */
    if (sbuf.st_ctime > sbuf.st_atime) {
      tp[0] = sbuf.st_atime;	/* preserve atime and mtime */
      tp[1] = sbuf.st_mtime;
      utime (tmp,tp);		/* set the times */
    }
  }
				/* in case INBOX but not mbx format */
  else if (((error = errno) == ENOENT) && !compare_cstring (name,"INBOX"))
    error = -1;
  if ((ret < 0) && ld && (*ld >= 0)) {
    unlockfd (*ld,lock);
    *ld = -1;
  }
  errno = error;		/* return as last error */
  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)
{
  void *ret = NIL;
  switch ((int) function) {
  case GET_INBOXPATH:
    if (value) ret = mbx_file ((char *) value,"INBOX");
    break;
  case SET_ONETIMEEXPUNGEATPING:
    if (value) ((MBXLOCAL *) ((MAILSTREAM *) value)->local)->expok = T;
  case GET_ONETIMEEXPUNGEATPING:
    if (value) ret = (void *)
      (((MBXLOCAL *) ((MAILSTREAM *) value)->local)->expok ? VOIDT : NIL);
    break;
  }
  return ret;
}


/* 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)