mtx.c

这是用C编写IMAP源代码

/*
 * Program:	MTX 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:	22 May 1990
 * Last Edited:	8 March 2005
 * 
 * The IMAP toolkit provided in this Distribution is
 * Copyright 1988-2005 University of Washington.
 * The full text of our legal notices is contained in the file called
 * CPYRIGHT, included with this Distribution.
 */


/*				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"

/* MTX I/O stream local data */
	
typedef struct mtx_local {
  unsigned int shouldcheck: 1;	/* if ping should do a check instead */
  unsigned int mustcheck: 1;	/* if ping must do a check instead */
  int fd;			/* file descriptor for I/O */
  off_t filesize;		/* file size parsed */
  time_t filetime;		/* last file time */
  time_t lastsnarf;		/* last snarf time */
  unsigned char *buf;		/* temporary buffer */
  unsigned long buflen;		/* current size of temporary buffer */
  unsigned long uid;		/* current text uid */
  SIZEDTEXT text;		/* current text */
} MTXLOCAL;


/* Convenient access to local data */

#define LOCAL ((MTXLOCAL *) stream->local)


/* Function prototypes */

DRIVER *mtx_valid (char *name);
int mtx_isvalid (char *name,char *tmp);
void *mtx_parameters (long function,void *value);
void mtx_scan (MAILSTREAM *stream,char *ref,char *pat,char *contents);
void mtx_list (MAILSTREAM *stream,char *ref,char *pat);
void mtx_lsub (MAILSTREAM *stream,char *ref,char *pat);
long mtx_create (MAILSTREAM *stream,char *mailbox);
long mtx_delete (MAILSTREAM *stream,char *mailbox);
long mtx_rename (MAILSTREAM *stream,char *old,char *newname);
long mtx_status (MAILSTREAM *stream,char *mbx,long flags);
MAILSTREAM *mtx_open (MAILSTREAM *stream);
void mtx_close (MAILSTREAM *stream,long options);
void mtx_flags (MAILSTREAM *stream,char *sequence,long flags);
char *mtx_header (MAILSTREAM *stream,unsigned long msgno,
		  unsigned long *length,long flags);
long mtx_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags);
void mtx_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags);
void mtx_flagmsg (MAILSTREAM *stream,MESSAGECACHE *elt);
long mtx_ping (MAILSTREAM *stream);
void mtx_check (MAILSTREAM *stream);
void mtx_snarf (MAILSTREAM *stream);
void mtx_expunge (MAILSTREAM *stream);
long mtx_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options);
long mtx_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data);

char *mtx_file (char *dst,char *name);
long mtx_parse (MAILSTREAM *stream);
MESSAGECACHE *mtx_elt (MAILSTREAM *stream,unsigned long msgno);
void mtx_read_flags (MAILSTREAM *stream,MESSAGECACHE *elt);
void mtx_update_status (MAILSTREAM *stream,unsigned long msgno,long syncflag);
unsigned long mtx_hdrpos (MAILSTREAM *stream,unsigned long msgno,
			  unsigned long *size);

/* MTX mail routines */


/* Driver dispatch used by MAIL */

DRIVER mtxdriver = {
  "mtx",			/* driver name */
				/* driver flags */
  DR_LOCAL|DR_MAIL|DR_CRLF|DR_NOSTICKY|DR_LOCKING,
  (DRIVER *) NIL,		/* next driver */
  mtx_valid,			/* mailbox is valid for us */
  mtx_parameters,		/* manipulate parameters */
  mtx_scan,			/* scan mailboxes */
  mtx_list,			/* list mailboxes */
  mtx_lsub,			/* list subscribed mailboxes */
  NIL,				/* subscribe to mailbox */
  NIL,				/* unsubscribe from mailbox */
  dummy_create,			/* create mailbox */
  mtx_delete,			/* delete mailbox */
  mtx_rename,			/* rename mailbox */
  mtx_status,			/* status of mailbox */
  mtx_open,			/* open mailbox */
  mtx_close,			/* close mailbox */
  mtx_flags,			/* fetch message "fast" attributes */
  mtx_flags,			/* fetch message flags */
  NIL,				/* fetch overview */
  NIL,				/* fetch message envelopes */
  mtx_header,			/* fetch message header */
  mtx_text,			/* fetch message body */
  NIL,				/* fetch partial message text */
  NIL,				/* unique identifier */
  NIL,				/* message number */
  mtx_flag,			/* modify flags */
  mtx_flagmsg,			/* per-message modify flags */
  NIL,				/* search for message based on criteria */
  NIL,				/* sort messages */
  NIL,				/* thread messages */
  mtx_ping,			/* ping mailbox to see if still alive */
  mtx_check,			/* check for new messages */
  mtx_expunge,			/* expunge deleted messages */
  mtx_copy,			/* copy messages to another mailbox */
  mtx_append,			/* append string message to mailbox */
  NIL				/* garbage collect stream */
};

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

DRIVER *mtx_valid (char *name)
{
  char tmp[MAILTMPLEN];
  return mtx_isvalid (name,tmp) ? &mtxdriver : NIL;
}


/* MTX mail test for valid mailbox
 * Accepts: mailbox name
 * Returns: T if valid, NIL otherwise
 */

int mtx_isvalid (char *name,char *tmp)
{
  int fd;
  int ret = NIL;
  char *s,file[MAILTMPLEN];
  struct stat sbuf;
  time_t tp[2];
  errno = EINVAL;		/* assume invalid argument */
				/* if file, get its status */
  if ((s = mtx_file (file,name)) && !stat (s,&sbuf)) {
    if (!sbuf.st_size) {	/* allow empty file if INBOX */
      if ((s = mailboxfile (tmp,name)) && !*s) ret = T;
      else errno = 0;		/* empty file */
    }
    else if ((fd = open (file,O_RDONLY,NIL)) >= 0) {
      memset (tmp,'\0',MAILTMPLEN);
      if ((read (fd,tmp,64) >= 0) && (s = strchr (tmp,'\015')) &&
	  (s[1] == '\012')) {	/* valid format? */
	*s = '\0';		/* tie off header */
				/* must begin with dd-mmm-yy" */
	ret = (((tmp[2] == '-' && tmp[6] == '-') ||
		(tmp[1] == '-' && tmp[5] == '-')) &&
	       (s = strchr (tmp+18,',')) && strchr (s+2,';')) ? T : NIL;
      }
      else errno = -1;		/* bogus format */
      close (fd);		/* close the file */
				/* \Marked status? */
      if (sbuf.st_ctime > sbuf.st_atime) {
	tp[0] = sbuf.st_atime;	/* preserve atime and mtime */
	tp[1] = sbuf.st_mtime;
	utime (file,tp);	/* set the times */
      }
    }
  }
				/* in case INBOX but not mtx format */
  else if ((errno == ENOENT) && !compare_cstring (name,"INBOX")) errno = -1;
  return ret;			/* return what we should */
}

/* MTX manipulate driver parameters
 * Accepts: function code
 *	    function-dependent value
 * Returns: function-dependent return value
 */

void *mtx_parameters (long function,void *value)
{
  void *ret = NIL;
  switch ((int) function) {
  case GET_INBOXPATH:
    if (value) ret = mtx_file ((char *) value,"INBOX");
    break;
  }
  return ret;
}


/* MTX mail scan mailboxes
 * Accepts: mail stream
 *	    reference
 *	    pattern to search
 *	    string to scan
 */

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


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

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


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

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

long mtx_delete (MAILSTREAM *stream,char *mailbox)
{
  return mtx_rename (stream,mailbox,NIL);
}


/* MTX mail rename mailbox
 * Accepts: MAIL stream
 *	    old mailbox name
 *	    new mailbox name (or NIL for delete)
 * Returns: T on success, NIL on failure
 */

long mtx_rename (MAILSTREAM *stream,char *old,char *newname)
{
  long ret = T;
  char c,*s,tmp[MAILTMPLEN],file[MAILTMPLEN],lock[MAILTMPLEN];
  int fd,ld;
  struct stat sbuf;
  if (!mtx_file (file,old) ||
      (newname && !((s = mailboxfile (tmp,newname)) && *s))) {
    sprintf (tmp,newname ?
	     "Can't rename mailbox %.80s to %.80s: invalid name" :
	     "Can't delete mailbox %.80s: invalid name",
	     old,newname);
    MM_LOG (tmp,ERROR);
    return NIL;
  }
  else if ((fd = open (file,O_RDWR,NIL)) < 0) {
    sprintf (tmp,"Can't open mailbox %.80s: %s",old,strerror (errno));
    MM_LOG (tmp,ERROR);
    return NIL;
  }
				/* get exclusive parse/append permission */
  if ((ld = lockfd (fd,lock,LOCK_EX)) < 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 %.80s is in use by another process",old);
    MM_LOG (tmp,ERROR);
    unlockfd (ld,lock);		/* release exclusive parse/append permission */
    return NIL;
  }

  if (newname) {		/* want rename? */
    if (s = strrchr (tmp,'/')) {/* found superior to destination name? */
      c = *++s;			/* remember first character of inferior */
      *s = '\0';		/* tie off to get just superior */
				/* name doesn't exist, create it */
      if ((stat (tmp,&sbuf) || ((sbuf.st_mode & S_IFMT) != S_IFDIR)) &&
	  !dummy_create_path (stream,tmp,get_dir_protection (newname)))
	ret = NIL;
      else *s = c;		/* restore full name */
    }
				/* rename the file */
    if (ret && rename (file,tmp)) {
      sprintf (tmp,"Can't rename mailbox %.80s to %.80s: %s",old,newname,
	       strerror (errno));
      MM_LOG (tmp,ERROR);
      ret = NIL;		/* set failure */
    }
  }
  else if (unlink (file)) {
    sprintf (tmp,"Can't delete mailbox %.80s: %s",old,strerror (errno));
    MM_LOG (tmp,ERROR);
    ret = NIL;			/* set failure */
  }
  flock (fd,LOCK_UN);		/* release lock on the file */
  close (fd);			/* close the file */
  unlockfd (ld,lock);		/* release exclusive parse/append permission */
				/* recreate file if renamed INBOX */
  if (ret && !compare_cstring (old,"INBOX")) dummy_create (NIL,"INBOX.MTX");
  return ret;			/* return success */
}

/* Mtx Mail status
 * Accepts: mail stream
 *	    mailbox name
 *	    status flags
 * Returns: T on success, NIL on failure
 */

long mtx_status (MAILSTREAM *stream,char *mbx,long flags)
{
  MAILSTATUS status;
  unsigned long i;
  MAILSTREAM *tstream = NIL;
  MAILSTREAM *systream = NIL;
				/* make temporary stream (unless this mbx) */
  if (!stream && !(stream = tstream =
		   mail_open (NIL,mbx,OP_READONLY|OP_SILENT))) return NIL;
  status.flags = flags;		/* return status values */
  status.messages = stream->nmsgs;
  status.recent = stream->recent;
  if (flags & SA_UNSEEN)	/* must search to get unseen messages */
    for (i = 1,status.unseen = 0; i <= stream->nmsgs; i++)
      if (!mail_elt (stream,i)->seen) status.unseen++;
  status.uidnext = stream->uid_last + 1;
  status.uidvalidity = stream->uid_validity;
				/* calculate post-snarf results */
  if (!status.recent && stream->inbox &&
      (systream = mail_open (NIL,sysinbox (),OP_READONLY|OP_SILENT))) {
    status.messages += systream->nmsgs;
    status.recent += systream->recent;
    if (flags & SA_UNSEEN)	/* must search to get unseen messages */
      for (i = 1; i <= systream->nmsgs; i++)
	if (!mail_elt (systream,i)->seen) status.unseen++;
				/* kludge but probably good enough */
    status.uidnext += systream->nmsgs;
  }
  MM_STATUS(stream,mbx,&status);/* pass status to main program */
  if (tstream) mail_close (tstream);
  if (systream) mail_close (systream);
  return T;			/* success */
}

/* MTX mail open
 * Accepts: stream to open
 * Returns: stream on success, NIL on failure
 */

MAILSTREAM *mtx_open (MAILSTREAM *stream)
{
  int fd,ld;
  char tmp[MAILTMPLEN];
  blocknotify_t bn = (blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
				/* return prototype for OP_PROTOTYPE call */
  if (!stream) return user_flags (&mtxproto);
  if (stream->local) fatal ("mtx recycle stream");
  user_flags (stream);		/* set up user flags */
				/* canonicalize the mailbox name */
  if (!mtx_file (tmp,stream->mailbox)) {
    sprintf (tmp,"Can't open - invalid name: %.80s",stream->mailbox);
    mm_log (tmp,ERROR);
  }
  if (stream->rdonly ||
      (fd = open (tmp,O_RDWR,NIL)) < 0) {
    if ((fd = open (tmp,O_RDONLY,NIL)) < 0) {
      sprintf (tmp,"Can't open mailbox: %.80s",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 (MTXLOCAL));
  LOCAL->fd = fd;		/* bind the file */
  LOCAL->buf = (char *) fs_get (MAXMESSAGESIZE + 1);
  LOCAL->buflen = MAXMESSAGESIZE;
  LOCAL->text.data = (unsigned char *)
    fs_get ((LOCAL->text.size = MAXMESSAGESIZE) + 1);
				/* note if an INBOX or not */
  stream->inbox = !compare_cstring (stream->mailbox,"INBOX");
  fs_give ((void **) &stream->mailbox);
  stream->mailbox = cpystr (tmp);
				/* get shared parse permission */
  if ((ld = lockfd (fd,tmp,LOCK_SH)) < 0) {
    MM_LOG ("Unable to lock open mailbox",ERROR);
    return NIL;
  }
  (*bn) (BLOCK_FILELOCK,NIL);
  flock (LOCAL->fd,LOCK_SH);	/* lock the file */
  (*bn) (BLOCK_NONE,NIL);
  unlockfd (ld,tmp);		/* release shared parse permission */
  LOCAL->filesize = 0;		/* initialize parsed file size */
				/* time not set up yet */
  LOCAL->lastsnarf = LOCAL->filetime = 0;
  LOCAL->mustcheck = LOCAL->shouldcheck = NIL;
  stream->sequence++;		/* bump sequence number */
				/* parse mailbox */
  stream->nmsgs = stream->recent = 0;
  if (mtx_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;
  return stream;		/* return stream to caller */
}

/* MTX mail close
 * Accepts: MAIL stream
 *	    close options
 */

void mtx_close (MAILSTREAM *stream,long options)