mbx.c

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/*
 * 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:	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 "mbx.h"
#include "misc.h"
#include "dummy.h"


/* 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 */
  unsigned long uid;		/* current text uid */
  SIZEDTEXT text;		/* current text */
  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);
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);
void mbx_expunge (MAILSTREAM *stream);
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];
  return mbx_isvalid (NIL,name,tmp) ? &mbxdriver : NIL;
}


/* MBX mail test for valid mailbox
 * Accepts: returned stream with valid mailbox keywords
 *	    mailbox name
 *	    scratch buffer
 * Returns: T if valid, NIL otherwise
 */

int mbx_isvalid (MAILSTREAM **stream,char *name,char *tmp)
{
  int fd;
  int ret = NIL;
  unsigned long i;
  unsigned char *s,*t,hdr[HDRSIZE];
  struct stat sbuf;
  time_t tp[2];
  errno = EINVAL;		/* assume invalid argument */
  if ((s = mbx_file (tmp,name)) && !stat (s,&sbuf) &&
      ((fd = open (tmp,O_RDONLY|O_BINARY,NIL)) >= 0)) {
    errno = -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 (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 = T;
    if (stream) {		/* stream specified? */
      *stream = (MAILSTREAM *) memset (fs_get (sizeof (MAILSTREAM)),0,
				       sizeof (MAILSTREAM));
      for (i = 0, s = hdr + 25;	/* parse user flags */
	   (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);
      }
    }
    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 (tmp,tp);		/* set the times */
    }
  }
				/* in case INBOX but not mbx format */
  else if ((errno == ENOENT) && !compare_cstring (name,"INBOX")) errno = -1;
  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)
{
  if (stream) dummy_lsub (NIL,ref,pat);
}

/* MBX mail create mailbox
 * Accepts: MAIL stream
 *	    mailbox name to create
 * Returns: T on success, NIL on failure
 */

long mbx_create (MAILSTREAM *stream,char *mailbox)
{
  char *s,*t,mbx[MAILTMPLEN],tmp[HDRSIZE];
  long ret = NIL;
  int i,fd;
  if (!(s = mbx_file (mbx,mailbox))) {
    sprintf (mbx,"Can't create %.80s: invalid name",mailbox);
    MM_LOG (mbx,ERROR);
  }
				/* create underlying file */
  else if (dummy_create_path (stream,s,get_dir_protection (mailbox))) {
				/* done if made directory */
    if ((s = strrchr (s,'/')) && !s[1]) return T;
    if ((fd = open (mbx,O_WRONLY|O_BINARY,
		    (int) mail_parameters (NIL,GET_MBXPROTECTION,NIL))) < 0) {
      sprintf (tmp,"Can't reopen mailbox node %.80s: %s",mbx,strerror (errno));
      MM_LOG (tmp,ERROR);
      unlink (mbx);		/* delete the file */
    }
    else {
      memset (tmp,'\0',HDRSIZE);/* initialize header */
      sprintf (s = tmp,"*mbx*\015\012%08lx00000000\015\012",
	       (unsigned long) time (0));
      for (i = 0; i < NUSERFLAGS; ++i) {
	t = (stream && stream->user_flags[i]) ? stream->user_flags[i] :
	  ((t = default_user_flag (i)) ? t : "");
	sprintf (s += strlen (s),"%s\015\012",t);
      }
      if (write (fd,tmp,HDRSIZE) != HDRSIZE) {
	sprintf (tmp,"Can't initialize mailbox node %.80s: %s",
		 mbx,strerror (errno));
	MM_LOG (tmp,ERROR);
	unlink (mbx);		/* delete the file */
      }
      else ret = T;		/* success */
      close (fd);		/* close file */
    }
  }
				/* set proper protections */
  return ret ? set_mbx_protections (mailbox,mbx) : NIL;
}


/* MBX mail delete mailbox
 * Accepts: MAIL stream
 *	    mailbox name to delete
 * Returns: T on success, NIL on failure
 */

long mbx_delete (MAILSTREAM *stream,char *mailbox)
{
  return mbx_rename (stream,mailbox,NIL);
}

/* MBX mail rename mailbox
 * Accepts: MAIL stream
 *	    old mailbox name
 *	    new mailbox name (or NIL for delete)
 * Returns: T on success, NIL on failure
 */

long mbx_rename (MAILSTREAM *stream,char *old,char *newname)
{
  long ret = LONGT;
  char c,*s,tmp[MAILTMPLEN],file[MAILTMPLEN],lock[MAILTMPLEN];
  int fd,ld;
  struct stat sbuf;
  if (!mbx_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|O_BINARY,NIL)) < 0) {
    sprintf (tmp,"Can't open mailbox %.80s: %s",old,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 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? */
				/* found superior to destination name? */
    if (s = strrchr (tmp,'/')) {
      c = *++s;			/* remember first character of inferior */
      *s = '\0';		/* tie off to get just superior */
				/* 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 */
  unlockfd (ld,lock);		/* release exclusive parse/append permission */
  close (fd);			/* close the file */
				/* recreate file if renamed INBOX */
  if (ret && !compare_cstring (old,"INBOX")) mbx_create (NIL,"INBOX");
  return ret;			/* return success */
}

/* MBX Mail status
 * Accepts: mail stream
 *	    mailbox name
 *	    status flags
 * Returns: T on success, NIL on failure
 */

long mbx_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 =