* Clean up some function definitions to comply with strict

[alpine.git] / imap / src / osdep / unix / mx.c

/* ========================================================================
 * Copyright 1988-2008 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:     MX mail routines
 *
 * Author(s):   Mark Crispin
 *              Networks and Distributed Computing
 *              Computing & Communications
 *              University of Washington
 *              Administration Building, AG-44
 *              Seattle, WA  98195
 *              Internet: MRC@CAC.Washington.EDU
 *
 * Date:        3 May 1996
 * Last Edited: 6 January 2008
 */


#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#ifndef errno
extern int errno;               /* just in case */
#endif
#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"
\f
/* Index file */

#define MXINDEXNAME "/.mxindex"
#define MXINDEX(d,s) strcat (mx_file (d,s),MXINDEXNAME)


/* MX I/O stream local data */
        
typedef struct mx_local {
  int fd;                       /* file descriptor of open index */
  unsigned char *buf;           /* temporary buffer */
  unsigned long buflen;         /* current size of temporary buffer */
  unsigned long cachedtexts;    /* total size of all cached texts */
  time_t scantime;              /* last time directory scanned */
} MXLOCAL;


/* Convenient access to local data */

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


/* Function prototypes */

DRIVER *mx_valid (char *name);
int mx_isvalid (char *name,char *tmp);
int mx_namevalid (char *name);
void *mx_parameters (long function,void *value);
long mx_dirfmttest (char *name);
void mx_scan (MAILSTREAM *stream,char *ref,char *pat,char *contents);
long mx_scan_contents (char *name,char *contents,unsigned long csiz,
                       unsigned long fsiz);
void mx_list (MAILSTREAM *stream,char *ref,char *pat);
void mx_lsub (MAILSTREAM *stream,char *ref,char *pat);
long mx_subscribe (MAILSTREAM *stream,char *mailbox);
long mx_unsubscribe (MAILSTREAM *stream,char *mailbox);
long mx_create (MAILSTREAM *stream,char *mailbox);
long mx_delete (MAILSTREAM *stream,char *mailbox);
long mx_rename (MAILSTREAM *stream,char *old,char *newname);
int mx_rename_work (char *src,size_t srcl,char *dst,size_t dstl,char *name);
MAILSTREAM *mx_open (MAILSTREAM *stream);
void mx_close (MAILSTREAM *stream,long options);
void mx_fast (MAILSTREAM *stream,char *sequence,long flags);
char *mx_fast_work (MAILSTREAM *stream,MESSAGECACHE *elt);
char *mx_header (MAILSTREAM *stream,unsigned long msgno,unsigned long *length,
                 long flags);
long mx_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags);
void mx_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags);
void mx_flagmsg (MAILSTREAM *stream,MESSAGECACHE *elt);
long mx_ping (MAILSTREAM *stream);
void mx_check (MAILSTREAM *stream);
long mx_expunge (MAILSTREAM *stream,char *sequence,long options);
long mx_copy (MAILSTREAM *stream,char *sequence,char *mailbox,
              long options);
long mx_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data);
long mx_append_msg (MAILSTREAM *stream,char *flags,MESSAGECACHE *elt,
                    STRING *st,SEARCHSET *set);

int mx_select (const struct direct *name);
int mx_numsort (const struct direct **d1,const struct direct **d2);
char *mx_file (char *dst,char *name);
long mx_lockindex (MAILSTREAM *stream);
void mx_unlockindex (MAILSTREAM *stream);
void mx_setdate (char *file,MESSAGECACHE *elt);

\f
/* MX mail routines */


/* Driver dispatch used by MAIL */

DRIVER mxdriver = {
  "mx",                         /* driver name */
                                /* driver flags */
  DR_MAIL|DR_LOCAL|DR_NOFAST|DR_CRLF|DR_LOCKING|DR_DIRFMT,
  (DRIVER *) NIL,               /* next driver */
  mx_valid,                     /* mailbox is valid for us */
  mx_parameters,                /* manipulate parameters */
  mx_scan,                      /* scan mailboxes */
  mx_list,                      /* find mailboxes */
  mx_lsub,                      /* find subscribed mailboxes */
  mx_subscribe,                 /* subscribe to mailbox */
  mx_unsubscribe,               /* unsubscribe from mailbox */
  mx_create,                    /* create mailbox */
  mx_delete,                    /* delete mailbox */
  mx_rename,                    /* rename mailbox */
  mail_status_default,          /* status of mailbox */
  mx_open,                      /* open mailbox */
  mx_close,                     /* close mailbox */
  mx_fast,                      /* fetch message "fast" attributes */
  NIL,                          /* fetch message flags */
  NIL,                          /* fetch overview */
  NIL,                          /* fetch message envelopes */
  mx_header,                    /* fetch message header only */
  mx_text,                      /* fetch message body only */
  NIL,                          /* fetch partial message test */
  NIL,                          /* unique identifier */
  NIL,                          /* message number */
  mx_flag,                      /* modify flags */
  mx_flagmsg,                   /* per-message modify flags */
  NIL,                          /* search for message based on criteria */
  NIL,                          /* sort messages */
  NIL,                          /* thread messages */
  mx_ping,                      /* ping mailbox to see if still alive */
  mx_check,                     /* check for new messages */
  mx_expunge,                   /* expunge deleted messages */
  mx_copy,                      /* copy messages to another mailbox */
  mx_append,                    /* append string message to mailbox */
  NIL,                          /* garbage collect stream */
  NIL                           /* renew stream */
};

                                /* prototype stream */
MAILSTREAM mxproto = {&mxdriver};
\f
/* MX mail validate mailbox
 * Accepts: mailbox name
 * Returns: our driver if name is valid, NIL otherwise
 */

DRIVER *mx_valid (char *name)
{
  char tmp[MAILTMPLEN];
  return mx_isvalid (name,tmp) ? &mxdriver : NIL;
}


/* MX mail test for valid mailbox
 * Accepts: mailbox name
 *          temporary buffer to use
 * Returns: T if valid, NIL otherwise with errno holding dir stat error
 */

int mx_isvalid (char *name,char *tmp)
{
  struct stat sbuf;
  errno = NIL;                  /* zap error */
  if ((strlen (name) <= NETMAXMBX) && *mx_file (tmp,name) &&
      !stat (tmp,&sbuf) && ((sbuf.st_mode & S_IFMT) == S_IFDIR)) {
                                /* name is directory; is it mx? */
    if (!stat (MXINDEX (tmp,name),&sbuf) &&
        ((sbuf.st_mode & S_IFMT) == S_IFREG)) return T;
    errno = NIL;                /* directory but not mx */
  }
  else if (!compare_cstring (name,"INBOX")) errno = NIL;
  return NIL;
}


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

int mx_namevalid (char *name)
{
  char *s = (*name == '/') ? name + 1 : name;
  while (s && *s) {             /* make sure valid name */
    if (isdigit (*s)) s++;      /* digit, check this node further... */
    else if (*s == '/') break;  /* all digit node, barf */
                                /* non-digit, skip to next node or return */
    else if (!((s = strchr (s+1,'/')) && *++s)) return T;
  }
  return NIL;                   /* all numeric or empty node */
}
\f
/* MX manipulate driver parameters
 * Accepts: function code
 *          function-dependent value
 * Returns: function-dependent return value
 */

void *mx_parameters (long function,void *value)
{
  void *ret = NIL;
  switch ((int) function) {
  case GET_INBOXPATH:
    if (value) ret = mailboxfile ((char *) value,"~/INBOX");
    break;
  case GET_DIRFMTTEST:
    ret = (void *) mx_dirfmttest;
    break;
  case GET_SCANCONTENTS:
    ret = (void *) mx_scan_contents;
    break;
  }
  return ret;
}


/* MX test for directory format internal node
 * Accepts: candidate node name
 * Returns: T if internal name, NIL otherwise
 */

long mx_dirfmttest (char *name)
{
  int c;
                                /* success if index name or all-numberic */
  if (strcmp (name,MXINDEXNAME+1))
    while ((c = *name++) != '\0') if (!isdigit (c)) return NIL;
  return LONGT;
}
\f
/* MX scan mailboxes
 * Accepts: mail stream
 *          reference
 *          pattern to search
 *          string to scan
 */

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


/* MX scan mailbox for contents
 * Accepts: mailbox name
 *          desired contents
 *          contents size
 *          file size (ignored)
 * Returns: NIL if contents not found, T if found
 */

long mx_scan_contents (char *name,char *contents,unsigned long csiz,
                        unsigned long fsiz)
{
  long i,nfiles;
  void *a;
  char *s;
  long ret = NIL;
  size_t namelen = strlen (name);
  struct stat sbuf;
  struct direct **names = NIL;
  if ((nfiles = scandir (name,&names,mx_select,mx_numsort)) > 0)
    for (i = 0; i < nfiles; ++i) {
      if (!ret) {
        sprintf (s = (char *) fs_get (namelen + strlen (names[i]->d_name) + 2),
                 "%s/%s",name,names[i]->d_name);
        if (!stat (s,&sbuf) && (csiz <= sbuf.st_size))
          ret = dummy_scan_contents (s,contents,csiz,sbuf.st_size);
        fs_give ((void **) &s);
      }
      fs_give ((void **) &names[i]);
    }
                                /* free directory list */
  if ((a = (void *) names) != NULL) fs_give ((void **) &a);
  return ret;
}
\f
/* MX list mailboxes
 * Accepts: mail stream
 *          reference
 *          pattern to search
 */

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


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

void mx_lsub (MAILSTREAM *stream,char *ref,char *pat)
{
  if (stream) dummy_lsub (NIL,ref,pat);
}
\f
/* MX mail subscribe to mailbox
 * Accepts: mail stream
 *          mailbox to add to subscription list
 * Returns: T on success, NIL on failure
 */

long mx_subscribe (MAILSTREAM *stream,char *mailbox)
{
  return sm_subscribe (mailbox);
}


/* MX mail unsubscribe to mailbox
 * Accepts: mail stream
 *          mailbox to delete from subscription list
 * Returns: T on success, NIL on failure
 */

long mx_unsubscribe (MAILSTREAM *stream,char *mailbox)
{
  return sm_unsubscribe (mailbox);
}
\f
/* MX mail create mailbox
 * Accepts: mail stream
 *          mailbox name to create
 * Returns: T on success, NIL on failure
 */

long mx_create (MAILSTREAM *stream,char *mailbox)
{
  DRIVER *test;
  int fd;
  char *s,tmp[MAILTMPLEN];
  int mask = umask (0);
  long ret = NIL;
  if (!mx_namevalid (mailbox))  /* validate name */
    sprintf (tmp,"Can't create mailbox %.80s: invalid MX-format name",mailbox);
                                /* must not already exist */
  else if ((test = mail_valid (NIL,mailbox,NIL)) &&
           strcmp (test->name,"dummy"))
    sprintf (tmp,"Can't create mailbox %.80s: mailbox already exists",mailbox);
                                /* create directory */
  else if (!dummy_create_path (stream,MXINDEX (tmp,mailbox),
                               get_dir_protection (mailbox)))
    sprintf (tmp,"Can't create mailbox %.80s: %s",mailbox,strerror (errno));
  else {                        /* success */
                                /* set index protection */
    set_mbx_protections (mailbox,tmp);
                                /* tie off directory name */
    *(s = strrchr (tmp,'/') + 1) = '\0';
                                /* set directory protection */
    set_mbx_protections (mailbox,tmp);
    ret = LONGT;
  }
  umask (mask);                 /* restore mask */
  if (!ret) MM_LOG (tmp,ERROR); /* some error */
  return ret;
}
\f
/* MX mail delete mailbox
 *          mailbox name to delete
 * Returns: T on success, NIL on failure
 */

long mx_delete (MAILSTREAM *stream,char *mailbox)
{
  DIR *dirp;
  struct direct *d;
  char *s;
  char tmp[MAILTMPLEN];
  if (!mx_isvalid (mailbox,tmp))
    sprintf (tmp,"Can't delete mailbox %.80s: no such mailbox",mailbox);
                                /* delete index */
  else if (unlink (MXINDEX (tmp,mailbox)))
    sprintf (tmp,"Can't delete mailbox %.80s index: %s",
             mailbox,strerror (errno));
  else {                        /* get directory name */
    *(s = strrchr (tmp,'/')) = '\0';
    if ((dirp = opendir (tmp)) != NULL) {       /* open directory */
      *s++ = '/';               /* restore delimiter */
                                /* massacre messages */
      while ((d = readdir (dirp)) != NULL) if (mx_select (d)) {
        strcpy (s,d->d_name);   /* make path */
        unlink (tmp);           /* sayonara */
      }
      closedir (dirp);          /* flush directory */
      *(s = strrchr (tmp,'/')) = '\0';
      if (rmdir (tmp)) {        /* try to remove the directory */
        sprintf (tmp,"Can't delete name %.80s: %s",mailbox,strerror (errno));
        MM_LOG (tmp,WARN);
      }
    }
    return T;                   /* always success */
  }
  MM_LOG (tmp,ERROR);           /* something failed */
  return NIL;
}
\f
/* MX mail rename mailbox
 * Accepts: MX mail stream
 *          old mailbox name
 *          new mailbox name
 * Returns: T on success, NIL on failure
 */

long mx_rename (MAILSTREAM *stream,char *old,char *newname)
{
  char c,*s,tmp[MAILTMPLEN],tmp1[MAILTMPLEN];
  struct stat sbuf;
  if (!mx_isvalid (old,tmp))
    sprintf (tmp,"Can't rename mailbox %.80s: no such mailbox",old);
  else if (!mx_namevalid (newname))
    sprintf (tmp,"Can't rename to mailbox %.80s: invalid MX-format name",
             newname);
                                /* new mailbox name must not be valid */
  else if (mx_isvalid (newname,tmp))
    sprintf (tmp,"Can't rename to mailbox %.80s: destination already exists",
             newname);
  else {
    mx_file (tmp,old);          /* build old directory name */
    mx_file (tmp1,newname);     /* and new directory name */
                                /* easy if not INBOX */
    if (compare_cstring (old,"INBOX")) {
                                /* found superior to destination name? */
      if ((s = strrchr (mx_file (tmp1,newname),'/')) != NULL) {
        c = *++s;           /* remember first character of inferior */
        *s = '\0';              /* tie off to get just superior */
                                /* name doesn't exist, create it */
        if ((stat (tmp1,&sbuf) || ((sbuf.st_mode & S_IFMT) != S_IFDIR)) &&
            !dummy_create_path (stream,tmp1,get_dir_protection (newname)))
          return NIL;
        *s = c;                 /* restore full name */
      }
      if (!rename (tmp,tmp1)) return LONGT;
    }
\f
                                /* RFC 3501 requires this */
    else if (dummy_create_path (stream,strcat (tmp1,"/"),
                                get_dir_protection (newname))) {
      void *a;
      int i,n,lasterror;
      struct direct **names = NIL;
      size_t srcl = strlen (tmp);
      size_t dstl = strlen (tmp1);
                                /* rename each mx file to new directory */
      for (i = lasterror = 0,n = scandir (tmp,&names,mx_select,mx_numsort);
           i < n; ++i) {
        if (mx_rename_work (tmp,srcl,tmp1,dstl,names[i]->d_name))
          lasterror = errno;
        fs_give ((void **) &names[i]);
      }
                                /* free directory list */
      if ((a = (void *) names) != NULL) fs_give ((void **) &a);
      if (lasterror || mx_rename_work (tmp,srcl,tmp1,dstl,MXINDEXNAME+1))
        errno = lasterror;
      else return mx_create (NIL,"INBOX");
    }
    sprintf (tmp,"Can't rename mailbox %.80s to %.80s: %s",
             old,newname,strerror (errno));
  }
  MM_LOG (tmp,ERROR);           /* something failed */
  return NIL;
}


/* MX rename worker routine
 * Accepts: source directory name
 *          source directory name length
 *          destination directory name
 *          destination directory name length
 *          name of node to move
 * Returns: zero if success, non-zero if error
 */

int mx_rename_work (char *src,size_t srcl,char *dst,size_t dstl,char *name)
{
  int ret;
  size_t len = strlen (name);
  char *s = (char *) fs_get (srcl + len + 2);
  char *d = (char *) fs_get (dstl + len + 1);
  sprintf (s,"%s/%s",src,name);
  sprintf (d,"%s%s",dst,name);
  ret = rename (s,d);
  fs_give ((void **) &s);
  fs_give ((void **) &d);
  return ret;
}
\f
/* MX mail open
 * Accepts: stream to open
 * Returns: stream on success, NIL on failure
 */

MAILSTREAM *mx_open (MAILSTREAM *stream)
{
  char tmp[MAILTMPLEN];
                                /* return prototype for OP_PROTOTYPE call */
  if (!stream) return user_flags (&mxproto);
  if (stream->local) fatal ("mx recycle stream");
  stream->local = fs_get (sizeof (MXLOCAL));
                                /* note if an INBOX or not */
  stream->inbox = !compare_cstring (stream->mailbox,"INBOX");
  mx_file (tmp,stream->mailbox);/* get directory name */
                                /* canonicalize mailbox name */
  fs_give ((void **) &stream->mailbox);
  stream->mailbox = cpystr (tmp);
                                /* make temporary buffer */
  LOCAL->buf = (char *) fs_get (CHUNKSIZE);
  LOCAL->buflen = CHUNKSIZE - 1;
  LOCAL->scantime = 0;          /* not scanned yet */
  LOCAL->fd = -1;               /* no index yet */
  LOCAL->cachedtexts = 0;       /* no cached texts */
  stream->sequence++;           /* bump sequence number */
                                /* parse mailbox */
  stream->nmsgs = stream->recent = 0;
  if (mx_ping (stream) && !(stream->nmsgs || stream->silent))
    MM_LOG ("Mailbox is empty",(long) NIL);
  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;
  stream->kwd_create = (stream->user_flags[NUSERFLAGS-1] || stream->rdonly) ?
    NIL : T;                    /* can we create new user flags? */
  return stream;                /* return stream to caller */
}
\f
/* MX mail close
 * Accepts: MAIL stream
 *          close options
 */

void mx_close (MAILSTREAM *stream,long options)
{
  if (LOCAL) {                  /* only if a file is open */
    int silent = stream->silent;
    stream->silent = T;         /* note this stream is dying */
    if (options & CL_EXPUNGE) mx_expunge (stream,NIL,NIL);
                                /* free local scratch buffer */
    if (LOCAL->buf) fs_give ((void **) &LOCAL->buf);
                                /* nuke the local data */
    fs_give ((void **) &stream->local);
    stream->dtb = NIL;          /* log out the DTB */
    stream->silent = silent;    /* reset silent state */
  }
}
\f
/* MX mail fetch fast information
 * Accepts: MAIL stream
 *          sequence
 *          option flags
 */

void mx_fast (MAILSTREAM *stream,char *sequence,long flags)
{
  unsigned long i;
  MESSAGECACHE *elt;
  if (stream && LOCAL &&
      ((flags & FT_UID) ? mail_uid_sequence (stream,sequence) :
       mail_sequence (stream,sequence)))
    for (i = 1; i <= stream->nmsgs; i++)
      if ((elt = mail_elt (stream,i))->sequence) mx_fast_work (stream,elt);
}


/* MX mail fetch fast information
 * Accepts: MAIL stream
 *          message cache element
 * Returns: name of message file
 */

char *mx_fast_work (MAILSTREAM *stream,MESSAGECACHE *elt)
{
  struct stat sbuf;
  struct tm *tm;
                                /* build message file name */
  sprintf (LOCAL->buf,"%s/%lu",stream->mailbox,elt->private.uid);
                                /* have size yet? */
  if (!elt->rfc822_size && !stat (LOCAL->buf,&sbuf)) {
                                /* make plausible IMAPish date string */
    tm = gmtime (&sbuf.st_mtime);
    elt->day = tm->tm_mday; elt->month = tm->tm_mon + 1;
    elt->year = tm->tm_year + 1900 - BASEYEAR;
    elt->hours = tm->tm_hour; elt->minutes = tm->tm_min;
    elt->seconds = tm->tm_sec;
    elt->zhours = 0; elt->zminutes = 0; elt->zoccident = 0;
    elt->rfc822_size = sbuf.st_size;
  }
  return (char *) LOCAL->buf;   /* return file name */
}
\f
/* MX mail fetch message header
 * Accepts: MAIL stream
 *          message # to fetch
 *          pointer to returned header text length
 *          option flags
 * Returns: message header in RFC822 format
 */

char *mx_header (MAILSTREAM *stream,unsigned long msgno,unsigned long *length,
                 long flags)
{
  unsigned long i;
  int fd;
  MESSAGECACHE *elt;
  *length = 0;                  /* default to empty */
  if (flags & FT_UID) return "";/* UID call "impossible" */
  elt = mail_elt (stream,msgno);/* get elt */
  if (!elt->private.msg.header.text.data) {
                                /* purge cache if too big */
    if (LOCAL->cachedtexts > max (stream->nmsgs * 4096,2097152)) {
      mail_gc (stream,GC_TEXTS);/* just can't keep that much */
      LOCAL->cachedtexts = 0;
    }
    if ((fd = open (mx_fast_work (stream,elt),O_RDONLY,NIL)) < 0) return "";
                                /* is buffer big enough? */
    if (elt->rfc822_size > LOCAL->buflen) {
      fs_give ((void **) &LOCAL->buf);
      LOCAL->buf = (char *) fs_get ((LOCAL->buflen = elt->rfc822_size) + 1);
    }
                                /* slurp message */
    read (fd,LOCAL->buf,elt->rfc822_size);
                                /* tie off file */
    LOCAL->buf[elt->rfc822_size] = '\0';
    close (fd);                 /* flush message file */
                                /* find end of header */
    if (elt->rfc822_size < 4) i = 0;
    else for (i = 4; (i < elt->rfc822_size) &&
              !((LOCAL->buf[i - 4] == '\015') &&
                (LOCAL->buf[i - 3] == '\012') &&
                (LOCAL->buf[i - 2] == '\015') &&
                (LOCAL->buf[i - 1] == '\012')); i++);
                                /* copy header */
    cpytxt (&elt->private.msg.header.text,LOCAL->buf,i);
    cpytxt (&elt->private.msg.text.text,LOCAL->buf+i,elt->rfc822_size - i);
                                /* add to cached size */
    LOCAL->cachedtexts += elt->rfc822_size;
  }
  *length = elt->private.msg.header.text.size;
  return (char *) elt->private.msg.header.text.data;
}
\f
/* MX mail fetch message text (body only)
 * Accepts: MAIL stream
 *          message # to fetch
 *          pointer to returned stringstruct
 *          option flags
 * Returns: T on success, NIL on failure
 */

long mx_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags)
{
  unsigned long i;
  MESSAGECACHE *elt;
                                /* UID call "impossible" */
  if (flags & FT_UID) return NIL;
  elt = mail_elt (stream,msgno);
                                /* snarf message if don't have it yet */
  if (!elt->private.msg.text.text.data) {
    mx_header (stream,msgno,&i,flags);
    if (!elt->private.msg.text.text.data) return NIL;
  }
                                /* mark as seen */
  if (!(flags & FT_PEEK) && mx_lockindex (stream)) {
    elt->seen = T;
    mx_unlockindex (stream);
    MM_FLAGS (stream,msgno);
  }
  INIT (bs,mail_string,elt->private.msg.text.text.data,
        elt->private.msg.text.text.size);
  return T;
}
\f
/* MX mail modify flags
 * Accepts: MAIL stream
 *          sequence
 *          flag(s)
 *          option flags
 */

void mx_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags)
{
  mx_unlockindex (stream);      /* finished with index */
}


/* MX per-message modify flags
 * Accepts: MAIL stream
 *          message cache element
 */

void mx_flagmsg (MAILSTREAM *stream,MESSAGECACHE *elt)
{
  mx_lockindex (stream);        /* lock index if not already locked */
}
\f
/* MX mail ping mailbox
 * Accepts: MAIL stream
 * Returns: T if stream alive, else NIL
 */

long mx_ping (MAILSTREAM *stream)
{
  MAILSTREAM *sysibx = NIL;
  MESSAGECACHE *elt,*selt;
  struct stat sbuf;
  char *s,tmp[MAILTMPLEN];
  int fd;
  unsigned long i,j,r,old;
  long nmsgs = stream->nmsgs;
  long recent = stream->recent;
  int silent = stream->silent;
  if (stat (stream->mailbox,&sbuf)) return NIL;
  stream->silent = T;           /* don't pass up exists events yet */
  if (sbuf.st_ctime != LOCAL->scantime) {
    struct direct **names = NIL;
    long nfiles = scandir (stream->mailbox,&names,mx_select,mx_numsort);
    if (nfiles < 0) nfiles = 0; /* in case error */
    old = stream->uid_last;
                                /* note scanned now */
    LOCAL->scantime = sbuf.st_ctime;
                                /* scan directory */
    for (i = 0; i < nfiles; ++i) {
                                /* if newly seen, add to list */
      if ((j = atoi (names[i]->d_name)) > old) {
                                /* swell the cache */
        mail_exists (stream,++nmsgs);
        stream->uid_last = (elt = mail_elt (stream,nmsgs))->private.uid = j;
        elt->valid = T;         /* note valid flags */
        if (old) {              /* other than the first pass? */
          elt->recent = T;      /* yup, mark as recent */
          recent++;             /* bump recent count */
        }
      }
      fs_give ((void **) &names[i]);
    }
                                /* free directory */
    if ((s = (void *) names) != NULL) fs_give ((void **) &s);
  }
  stream->nmsgs = nmsgs;        /* don't upset mail_uid() */
\f
                                /* if INBOX, snarf from system INBOX  */
  if (mx_lockindex (stream) && stream->inbox &&
      !strcmp (sysinbox (),stream->mailbox)) {
    old = stream->uid_last;
    MM_CRITICAL (stream);       /* go critical */
                                /* see if anything in system inbox */
    if (!stat (sysinbox (),&sbuf) && sbuf.st_size &&
        (sysibx = mail_open (sysibx,sysinbox (),OP_SILENT)) &&
        !sysibx->rdonly && (r = sysibx->nmsgs)) {
      for (i = 1; i <= r; ++i) {/* for each message in sysinbox mailbox */
                                /* build file name we will use */
        sprintf (LOCAL->buf,"%s/%lu",stream->mailbox,++old);
                                /* snarf message from Berkeley mailbox */
        selt = mail_elt (sysibx,i);
        if (((fd = open (LOCAL->buf,O_WRONLY|O_CREAT|O_EXCL,
                         (long) mail_parameters (NIL,GET_MBXPROTECTION,NIL)))
             >= 0) &&
            (s = mail_fetchheader_full (sysibx,i,NIL,&j,FT_PEEK)) &&
            (write (fd,s,j) == j) &&
            (s = mail_fetchtext_full (sysibx,i,&j,FT_PEEK)) &&
            (write (fd,s,j) == j) && !fsync (fd) && !close (fd)) {
                                /* swell the cache */
          mail_exists (stream,++nmsgs);
          stream->uid_last =    /* create new elt, note its file number */
            (elt = mail_elt (stream,nmsgs))->private.uid = old;
          recent++;             /* bump recent count */
                                /* set up initial flags and date */
          elt->valid = elt->recent = T;
          elt->seen = selt->seen;
          elt->deleted = selt->deleted;
          elt->flagged = selt->flagged;
          elt->answered = selt->answered;
          elt->draft = selt->draft;
          elt->day = selt->day;elt->month = selt->month;elt->year = selt->year;
          elt->hours = selt->hours;elt->minutes = selt->minutes;
          elt->seconds = selt->seconds;
          elt->zhours = selt->zhours; elt->zminutes = selt->zminutes;
          elt->zoccident = selt->zoccident;
          mx_setdate (LOCAL->buf,elt);
          sprintf (tmp,"%lu",i);/* delete it from the sysinbox */
          mail_flag (sysibx,tmp,"\\Deleted",ST_SET);
        }
        else {                  /* failed to snarf */
          if (fd) {             /* did it ever get opened? */
            close (fd);         /* close descriptor */
            unlink (LOCAL->buf);/* flush this file */
          }
          sprintf (tmp,"Message copy to MX mailbox failed: %.80s",
                   strerror (errno));
          MM_LOG (tmp,ERROR);
          r = 0;                /* stop the snarf in its tracks */
        }
      }
                                /* update scan time */
      if (!stat (stream->mailbox,&sbuf)) LOCAL->scantime = sbuf.st_ctime;      
      mail_expunge (sysibx);    /* now expunge all those messages */
    }
    if (sysibx) mail_close (sysibx);
    MM_NOCRITICAL (stream);     /* release critical */
  }
  mx_unlockindex (stream);      /* done with index */
  stream->silent = silent;      /* can pass up events now */
  mail_exists (stream,nmsgs);   /* notify upper level of mailbox size */
  mail_recent (stream,recent);
  return T;                     /* return that we are alive */
}
\f
/* MX mail check mailbox
 * Accepts: MAIL stream
 */

void mx_check (MAILSTREAM *stream)
{
  if (mx_ping (stream)) MM_LOG ("Check completed",(long) NIL);
}


/* MX mail expunge mailbox
 * Accepts: MAIL stream
 *          sequence to expunge if non-NIL
 *          expunge options
 * Returns: T, always
 */

long mx_expunge (MAILSTREAM *stream,char *sequence,long options)
{
  long ret;
  MESSAGECACHE *elt;
  unsigned long i = 1;
  unsigned long n = 0;
  unsigned long recent = stream->recent;
  if ((ret = (sequence ? ((options & EX_UID) ?
                         mail_uid_sequence (stream,sequence) :
                         mail_sequence (stream,sequence)) : LONGT) != 0L) &&
      mx_lockindex (stream)) {  /* lock the index */
    MM_CRITICAL (stream);       /* go critical */
    while (i <= stream->nmsgs) {/* for each message */
      elt = mail_elt (stream,i);/* if deleted, need to trash it */
      if (elt->deleted && (sequence ? elt->sequence : T)) {
        sprintf (LOCAL->buf,"%s/%lu",stream->mailbox,elt->private.uid);
        if (unlink (LOCAL->buf)) {/* try to delete the message */
          sprintf (LOCAL->buf,"Expunge of message %lu failed, aborted: %s",i,
                   strerror (errno));
          MM_LOG (LOCAL->buf,(long) NIL);
          break;
        }
                                /* note uncached */
        LOCAL->cachedtexts -= ((elt->private.msg.header.text.data ?
                                elt->private.msg.header.text.size : 0) +
                               (elt->private.msg.text.text.data ?
                                elt->private.msg.text.text.size : 0));
        mail_gc_msg (&elt->private.msg,GC_ENV | GC_TEXTS);
        if(elt->recent)--recent;/* if recent, note one less recent message */
        mail_expunged(stream,i);/* notify upper levels */
        n++;                    /* count up one more expunged message */
      }
      else i++;                 /* otherwise try next message */
    }
    if (n) {                    /* output the news if any expunged */
      sprintf (LOCAL->buf,"Expunged %lu messages",n);
      MM_LOG (LOCAL->buf,(long) NIL);
    }
    else MM_LOG ("No messages deleted, so no update needed",(long) NIL);
    MM_NOCRITICAL (stream);     /* release critical */
    mx_unlockindex (stream);    /* finished with index */
                                /* notify upper level of new mailbox size */
    mail_exists (stream,stream->nmsgs);
    mail_recent (stream,recent);
  }
  return ret;
}
\f
/* MX mail copy message(s)
 * Accepts: MAIL stream
 *          sequence
 *          destination mailbox
 *          copy options
 * Returns: T if copy successful, else NIL
 */

long mx_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options)
{
  FDDATA d;
  STRING st;
  MESSAGECACHE *elt;
  MAILSTREAM *astream;
  struct stat sbuf;
  int fd;
  unsigned long i,j,uid,uidv;
  char *t,tmp[MAILTMPLEN];
  long ret;
  mailproxycopy_t pc =
    (mailproxycopy_t) mail_parameters (stream,GET_MAILPROXYCOPY,NIL);
                                /* make sure valid mailbox */
  if (!mx_valid (mailbox)) switch (errno) {
  case NIL:                     /* no error in stat() */
    if (pc) return (*pc) (stream,sequence,mailbox,options);
    sprintf (LOCAL->buf,"Not a MX-format mailbox: %.80s",mailbox);
    MM_LOG (LOCAL->buf,ERROR);
    return NIL;
  default:                      /* some stat() error */
    MM_NOTIFY (stream,"[TRYCREATE] Must create mailbox before copy",NIL);
    return NIL;
  }
                                /* copy the messages */
  if (!(ret = ((options & CP_UID) ? mail_uid_sequence (stream,sequence) :
               mail_sequence (stream,sequence))));
                                /* acquire stream to append to */
  else if (!(astream = mail_open (NIL,mailbox,OP_SILENT))) {
    MM_LOG ("Can't open copy mailbox",ERROR);
    ret = NIL;
  }
  else {
    MM_CRITICAL (stream);       /* go critical */
    if (!(ret = mx_lockindex (astream)))
      MM_LOG ("Message copy failed: unable to lock index",ERROR);
    else {
\f
      copyuid_t cu = (copyuid_t) mail_parameters (NIL,GET_COPYUID,NIL);
      SEARCHSET *source = cu ? mail_newsearchset () : NIL;
      SEARCHSET *dest = cu ? mail_newsearchset () : NIL;
      for (i = 1,uid = uidv = 0; ret && (i <= stream->nmsgs); i++) 
      if ((elt = mail_elt (stream,i))->sequence) {
        if ((ret = ((fd = open (mx_fast_work (stream,elt),O_RDONLY,NIL))
                   >= 0)) != 0L) {
          fstat (fd,&sbuf);     /* get size of message */
          d.fd = fd;            /* set up file descriptor */
          d.pos = 0;            /* start of file */
          d.chunk = LOCAL->buf;
          d.chunksize = CHUNKSIZE;
          INIT (&st,fd_string,&d,sbuf.st_size);
                                /* init flag string */
          tmp[0] = tmp[1] = '\0';
          if ((j = elt->user_flags) != 0L) do
            if ((t = stream->user_flags[find_rightmost_bit (&j)]) != NULL)
              strcat (strcat (tmp," "),t);
          while (j);
          if (elt->seen) strcat (tmp," \\Seen");
          if (elt->deleted) strcat (tmp," \\Deleted");
          if (elt->flagged) strcat (tmp," \\Flagged");
          if (elt->answered) strcat (tmp," \\Answered");
          if (elt->draft) strcat (tmp," \\Draft");
          tmp[0] = '(';         /* open list */
          strcat (tmp,")");     /* close list */
          if ((ret = mx_append_msg (astream,tmp,elt,&st,dest)) != 0L) {
                                /* add to source set if needed */
            if (source) mail_append_set (source,mail_uid (stream,i));
                                /* delete if doing a move */
            if (options & CP_MOVE) elt->deleted = T;
          }
        }
      }
                                /* return sets if doing COPYUID */
      if (cu && ret) (*cu) (stream,mailbox,astream->uid_validity,source,dest);
      else {                    /* flush any sets we may have built */
        mail_free_searchset (&source);
        mail_free_searchset (&dest);
      }
      mx_unlockindex (astream); /* unlock index */
    }
    MM_NOCRITICAL (stream);
    mail_close (astream);       /* finished with append stream */
  }
  return ret;                   /* return success */
}
\f
/* MX mail append message from stringstruct
 * Accepts: MAIL stream
 *          destination mailbox
 *          append callback
 *          data for callback
 * Returns: T if append successful, else NIL
 */

long mx_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data)
{
  MESSAGECACHE elt;
  MAILSTREAM *astream;
  char *flags,*date,tmp[MAILTMPLEN];
  STRING *message;
  long ret = LONGT;
                                /* default stream to prototype */
  if (!stream) stream = user_flags (&mxproto);
                                /* N.B.: can't use LOCAL->buf for tmp */
                                /* make sure valid mailbox */
  if (!mx_isvalid (mailbox,tmp)) switch (errno) {
  case ENOENT:                  /* no such file? */
    if (!compare_cstring (mailbox,"INBOX")) mx_create (NIL,"INBOX");
    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 MX-format mailbox name: %.80s",mailbox);
    MM_LOG (tmp,ERROR);
    return NIL;
  default:
    sprintf (tmp,"Not a MX-format mailbox: %.80s",mailbox);
    MM_LOG (tmp,ERROR);
    return NIL;
  }
\f
                                /* get first message */
  if (!MM_APPEND (af) (stream,data,&flags,&date,&message)) return NIL;
  if (!(astream = mail_open (NIL,mailbox,OP_SILENT))) {
    MM_LOG ("Can't open append mailbox",ERROR);
    return NIL;
  }
  MM_CRITICAL (astream);        /* go critical */
                                /* lock the index */
  if (!(ret = mx_lockindex (astream)))
    MM_LOG ("Message append failed: unable to lock index",ERROR);
  else {
    appenduid_t au = (appenduid_t) mail_parameters (NIL,GET_APPENDUID,NIL);
    SEARCHSET *dst = au ? mail_newsearchset () : NIL;
    do {
                                /* guard against zero-length */
      if (!(ret = SIZE (message)))
        MM_LOG ("Append of zero-length message",ERROR);
      else if (date && !(ret = mail_parse_date (&elt,date))) {
        sprintf (tmp,"Bad date in append: %.80s",date);
        MM_LOG (tmp,ERROR);
      }
      else ret = mx_append_msg (astream,flags,date ? &elt : NIL,message,dst)&&
             MM_APPEND (af) (stream,data,&flags,&date,&message);
    } while (ret && message);
                                /* return sets if doing APPENDUID */
    if (au && ret) (*au) (mailbox,astream->uid_validity,dst);
    else mail_free_searchset (&dst);
    mx_unlockindex (astream);   /* unlock index */
  }
  MM_NOCRITICAL (astream);      /* release critical */
  mail_close (astream);
  return ret;
}
\f
/* MX mail append single message
 * Accepts: MAIL stream
 *          flags for new message if non-NIL
 *          elt with source date if non-NIL
 *          stringstruct of message text
 *          searchset to place UID
 * Returns: T if success, NIL if failure
 */

long mx_append_msg (MAILSTREAM *stream,char *flags,MESSAGECACHE *elt,
                    STRING *st,SEARCHSET *set)
{
  char tmp[MAILTMPLEN];
  int fd;
  unsigned long uf;
  long f = mail_parse_flags (stream,flags,&uf);
                                /* make message file name */
  sprintf (tmp,"%s/%lu",stream->mailbox,++stream->uid_last);
  if ((fd = open (tmp,O_WRONLY|O_CREAT|O_EXCL,
                  (long) mail_parameters (NIL,GET_MBXPROTECTION,NIL))) < 0) {
    sprintf (tmp,"Can't create append message: %s",strerror (errno));
    MM_LOG (tmp,ERROR);
    return NIL;
  }
  while (SIZE (st)) {           /* copy the file */
    if (st->cursize && (write (fd,st->curpos,st->cursize) < 0)) {
      unlink (tmp);             /* delete file */
      close (fd);               /* close the file */
      sprintf (tmp,"Message append failed: %s",strerror (errno));
      MM_LOG (tmp,ERROR);
      return NIL;
    }
    SETPOS (st,GETPOS (st) + st->cursize);
  }
  close (fd);                   /* close the file */
  if (elt) mx_setdate (tmp,elt);/* set file date */
                                /* swell the cache */
  mail_exists (stream,++stream->nmsgs);
                                /* copy flags */
  mail_append_set (set,(elt = mail_elt (stream,stream->nmsgs))->private.uid =
                   stream->uid_last);
  if (f&fSEEN) elt->seen = T;
  if (f&fDELETED) elt->deleted = T;
  if (f&fFLAGGED) elt->flagged = T;
  if (f&fANSWERED) elt->answered = T;
  if (f&fDRAFT) elt->draft = T;
  elt->user_flags |= uf;
  return LONGT;
}
\f
/* Internal routines */


/* MX file name selection test
 * Accepts: candidate directory entry
 * Returns: T to use file name, NIL to skip it
 */

int mx_select (const struct direct *name)
{
  char c;
  char *s = (char *) name->d_name;
  while ((c = *s++) != '\0') if (!isdigit (c)) return NIL;
  return T;
}


/* MX file name comparison
 * Accepts: first candidate directory entry
 *          second candidate directory entry
 * Returns: negative if d1 < d2, 0 if d1 == d2, positive if d1 > d2
 */

int mx_numsort (const struct direct **d1,const struct direct **d2)
{
  return atoi ((*(struct direct **) d1)->d_name) -
    atoi ((*(struct direct **) d2)->d_name);
}


/* MX mail build file name
 * Accepts: destination string
 *          source
 * Returns: destination
 */

char *mx_file (char *dst,char *name)
{
  char *s;
                                /* empty string if mailboxfile fails */
  if (!mailboxfile (dst,name)) *dst = '\0';
                                /* driver-selected INBOX  */
  else if (!*dst) mailboxfile (dst,"~/INBOX");
                                /* tie off unnecessary trailing / */
  else if ((s = strrchr (dst,'/')) && !s[1]) *s = '\0';
  return dst;
}
\f
/* MX read and lock index
 * Accepts: MAIL stream
 * Returns: T if success, NIL if failure
 */

long mx_lockindex (MAILSTREAM *stream)
{
  unsigned long uf,sf,uid;
  int k = 0;
  unsigned long msgno = 1;
  struct stat sbuf;
  char *s,*t,*idx,tmp[2*MAILTMPLEN];
  MESSAGECACHE *elt;
  blocknotify_t bn = (blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
  if ((LOCAL->fd < 0) &&        /* get index file, no-op if already have it */
      (LOCAL->fd = open (strcat (strcpy (tmp,stream->mailbox),MXINDEXNAME),
                         O_RDWR|O_CREAT,
                         (long) mail_parameters (NIL,GET_MBXPROTECTION,NIL)))
      >= 0) {
    (*bn) (BLOCK_FILELOCK,NIL);
    flock (LOCAL->fd,LOCK_EX);  /* get exclusive lock */
    (*bn) (BLOCK_NONE,NIL);
    fstat (LOCAL->fd,&sbuf);    /* get size of index */
                                /* slurp index */
    read (LOCAL->fd,s = idx = (char *) fs_get (sbuf.st_size + 1),sbuf.st_size);
    idx[sbuf.st_size] = '\0';   /* tie off index */
                                /* parse index */
    if (sbuf.st_size) while (s && *s) switch (*s) {
    case 'V':                   /* UID validity record */
      stream->uid_validity = strtoul (s+1,&s,16);
      break;
    case 'L':                   /* UID last record */
      stream->uid_last = strtoul (s+1,&s,16);
      break;
    case 'K':                   /* keyword */
                                /* find end of keyword */
      if ((s = strchr (t = ++s,'\n')) != NULL) {
        *s++ = '\0';            /* tie off keyword */
                                /* copy keyword */
        if ((k < NUSERFLAGS) && !stream->user_flags[k] &&
            (strlen (t) <= MAXUSERFLAG)) stream->user_flags[k] = cpystr (t);
        k++;                    /* one more keyword */
      }
      break;
\f
    case 'M':                   /* message status record */
      uid = strtoul (s+1,&s,16);/* get UID for this message */
      if (*s == ';') {          /* get user flags */
        uf = strtoul (s+1,&s,16);
        if (*s == '.') {        /* get system flags */
          sf = strtoul (s+1,&s,16);
          while ((msgno <= stream->nmsgs) && (mail_uid (stream,msgno) < uid))
            msgno++;            /* find message number for this UID */
          if ((msgno <= stream->nmsgs) && (mail_uid (stream,msgno) == uid)) {
            (elt = mail_elt (stream,msgno))->valid = T;
            elt->user_flags=uf; /* set user and system flags in elt */
            if (sf & fSEEN) elt->seen = T;
            if (sf & fDELETED) elt->deleted = T;
            if (sf & fFLAGGED) elt->flagged = T;
            if (sf & fANSWERED) elt->answered = T;
            if (sf & fDRAFT) elt->draft = T;
          }
          break;
        }
      }
    default:                    /* bad news */
      sprintf (tmp,"Error in index: %.80s",s);
      MM_LOG (tmp,ERROR);
      *s = NIL;                 /* ignore remainder of index */
    }
    else {                      /* new index */
      stream->uid_validity = time (0);
      user_flags (stream);      /* init stream with default user flags */
    }
    fs_give ((void **) &idx);   /* flush index */
  }
  return (LOCAL->fd >= 0) ? T : NIL;
}
\f
/* MX write and unlock index
 * Accepts: MAIL stream
 */

#define MXIXBUFLEN 2048

void mx_unlockindex (MAILSTREAM *stream)
{
  unsigned long i,j;
  off_t size = 0;
  char *s,tmp[MXIXBUFLEN + 64];
  MESSAGECACHE *elt;
  if (LOCAL->fd >= 0) {
    lseek (LOCAL->fd,0,L_SET);  /* rewind file */
                                /* write header */
    sprintf (s = tmp,"V%08lxL%08lx",stream->uid_validity,stream->uid_last);
    for (i = 0; (i < NUSERFLAGS) && stream->user_flags[i]; ++i)
      sprintf (s += strlen (s),"K%s\n",stream->user_flags[i]);
                                /* write messages */
    for (i = 1; i <= stream->nmsgs; i++) {
                                /* filled buffer? */
      if (((s += strlen (s)) - tmp) > MXIXBUFLEN) {
        write (LOCAL->fd,tmp,j = s - tmp);
        size += j;
        *(s = tmp) = '\0';      /* dump out and restart buffer */
      }
      elt = mail_elt (stream,i);
      sprintf(s,"M%08lx;%08lx.%04x",elt->private.uid,elt->user_flags,(unsigned)
              ((fSEEN * elt->seen) + (fDELETED * elt->deleted) +
               (fFLAGGED * elt->flagged) + (fANSWERED * elt->answered) +
               (fDRAFT * elt->draft)));
    }
                                /* write tail end of buffer */
    if ((s += strlen (s)) != tmp) {
      write (LOCAL->fd,tmp,j = s - tmp);
      size += j;
    }
    ftruncate (LOCAL->fd,size);
    flock (LOCAL->fd,LOCK_UN);  /* unlock the index */
    close (LOCAL->fd);          /* finished with file */
    LOCAL->fd = -1;             /* no index now */
  }
}
\f
/* Set date for message
 * Accepts: file name
 *          elt containing date
 */

void mx_setdate (char *file,MESSAGECACHE *elt)
{
  time_t tp[2];
  tp[0] = time (0);             /* atime is now */
  tp[1] = mail_longdate (elt);  /* modification time */
  utime (file,tp);              /* set the times */
}