Fix error handling of `shcodec' and `urlcodec'

[s-mailx.git] / folder.c

/*@ S-nail - a mail user agent derived from Berkeley Mail.
 *@ Folder (mailbox) initialization, newmail announcement and related.
 *
 * Copyright (c) 2000-2004 Gunnar Ritter, Freiburg i. Br., Germany.
 * Copyright (c) 2012 - 2017 Steffen (Daode) Nurpmeso <steffen@sdaoden.eu>.
 */
/*
 * Copyright (c) 1980, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#undef n_FILE
#define n_FILE folder

#ifndef HAVE_AMALGAMATION
# include "nail.h"
#endif

#include <pwd.h>

/* Update mailname (if name != NULL) and displayname, return whether displayname
 * was large enough to swallow mailname */
static bool_t  _update_mailname(char const *name);
#ifdef HAVE_C90AMEND1 /* TODO unite __narrow_suffix() into one fun! */
SINLINE size_t __narrow_suffix(char const *cp, size_t cpl, size_t maxl);
#endif

/**/
static void a_folder_info(void);

static bool_t
_update_mailname(char const *name) /* TODO 2MUCH work, cache, prop of Object! */
{
   char *mailp, *dispp;
   size_t i, j;
   bool_t rv = TRU1;
   NYD_ENTER;

   /* Don't realpath(3) if it's only an update request */
   if (name != NULL) {
#ifdef HAVE_REALPATH
      enum protocol p = which_protocol(name, TRU1, TRU1, &name);

      if (p == PROTO_FILE || p == PROTO_MAILDIR) {
         if (realpath(name, mailname) == NULL && n_err_no != n_ERR_NOENT) {
            n_err(_("Can't canonicalize %s\n"), n_shexp_quote_cp(name, FAL0));
            rv = FAL0;
            goto jdocopy;
         }
      } else
jdocopy:
#endif
         n_strscpy(mailname, name, sizeof(mailname));
   }

   mailp = mailname;
   dispp = displayname;

   /* Don't display an absolute path but "+FOLDER" if under *folder* */
   /* C99 */{
      char const *folderp;

      if(*(folderp = n_folder_query()) != '\0'){
         i = strlen(folderp);
         if(!strncmp(folderp, mailp, i)){
            mailp += i;
            *dispp++ = '+';
         }
      }
   }

   /* We want to see the name of the folder .. on the screen */
   i = strlen(mailp);
   if (i < sizeof(displayname) -1)
      memcpy(dispp, mailp, i +1);
   else {
      rv = FAL0;
      /* Avoid disrupting multibyte sequences (if possible) */
#ifndef HAVE_C90AMEND1
      j = sizeof(displayname) / 3 - 1;
      i -= sizeof(displayname) - (1/* + */ + 3) - j;
#else
      j = field_detect_clip(sizeof(displayname) / 3, mailp, i);
      i = j + __narrow_suffix(mailp + j, i - j,
         sizeof(displayname) - (1/* + */ + 3 + 1) - j);
#endif
      snprintf(dispp, sizeof(displayname), "%.*s...%s",
         (int)j, mailp, mailp + i);
   }

   n_PS_ROOT_BLOCK((ok_vset(mailbox_resolved, mailname),
      ok_vset(mailbox_display, displayname)));
   NYD_LEAVE;
   return rv;
}

#ifdef HAVE_C90AMEND1
SINLINE size_t
__narrow_suffix(char const *cp, size_t cpl, size_t maxl)
{
   int err;
   size_t i, ok;
   NYD_ENTER;

   for (err = ok = i = 0; cpl > maxl || err;) {
      int ml = mblen(cp, cpl);
      if (ml < 0) { /* XXX _narrow_suffix(): mblen() error; action? */
         (void)mblen(NULL, 0);
         err = 1;
         ml = 1;
      } else {
         if (!err)
            ok = i;
         err = 0;
         if (ml == 0)
            break;
      }
      cp += ml;
      i += ml;
      cpl -= ml;
   }
   NYD_LEAVE;
   return ok;
}
#endif /* HAVE_C90AMEND1 */

static void
a_folder_info(void){
   struct message *mp;
   int u, n, d, s, hidden, moved;
   NYD2_ENTER;

   if(mb.mb_type == MB_VOID){
      fprintf(n_stdout, _("(Currently no active mailbox)"));
      goto jleave;
   }

   s = d = hidden = moved = 0;
   for (mp = message, n = 0, u = 0; PTRCMP(mp, <, message + msgCount); ++mp) {
      if (mp->m_flag & MNEW)
         ++n;
      if ((mp->m_flag & MREAD) == 0)
         ++u;
      if ((mp->m_flag & (MDELETED | MSAVED)) == (MDELETED | MSAVED))
         ++moved;
      if ((mp->m_flag & (MDELETED | MSAVED)) == MDELETED)
         ++d;
      if ((mp->m_flag & (MDELETED | MSAVED)) == MSAVED)
         ++s;
      if (mp->m_flag & MHIDDEN)
         ++hidden;
   }

   /* If displayname gets truncated the user effectively has no option to see
    * the full pathname of the mailbox, so print it at least for '? fi' */
   fprintf(n_stdout, "%s: ", n_shexp_quote_cp(
      (_update_mailname(NULL) ? displayname : mailname), FAL0));
   if (msgCount == 1)
      fprintf(n_stdout, _("1 message"));
   else
      fprintf(n_stdout, _("%d messages"), msgCount);
   if (n > 0)
      fprintf(n_stdout, _(" %d new"), n);
   if (u-n > 0)
      fprintf(n_stdout, _(" %d unread"), u);
   if (d > 0)
      fprintf(n_stdout, _(" %d deleted"), d);
   if (s > 0)
      fprintf(n_stdout, _(" %d saved"), s);
   if (moved > 0)
      fprintf(n_stdout, _(" %d moved"), moved);
   if (hidden > 0)
      fprintf(n_stdout, _(" %d hidden"), hidden);
   if (mb.mb_perm == 0)
      fprintf(n_stdout, _(" [Read-only]"));

jleave:
   putc('\n', n_stdout);
   NYD2_LEAVE;
}

FL int
setfile(char const *name, enum fedit_mode fm) /* TODO oh my god */
{
   /* TODO This all needs to be converted to URL:: and Mailbox:: */
   static int shudclob;

   struct stat stb;
   size_t offset;
   char const *who, *orig_name;
   int rv, omsgCount = 0;
   FILE *ibuf = NULL, *lckfp = NULL;
   bool_t isdevnull = FAL0;
   NYD_ENTER;

   n_pstate &= ~n_PS_SETFILE_OPENED;

   /* C99 */{
      enum fexp_mode fexpm;

      if((who = shortcut_expand(name)) != NULL){
         fexpm = FEXP_NSHORTCUT/* XXX | FEXP_NSHELL*/;
         name = who;
      }else
         fexpm = FEXP_FULL/* XXX FEXP_NSHELL*/;

      if(name[0] == '%'){
         char const *cp;

         fm |= FEDIT_SYSBOX; /* TODO fexpand() needs to tell is-valid-user! */
         if(*(who = &name[1]) == ':')
            ++who;
         if((cp = strrchr(who, '/')) != NULL)
            who = &cp[1];
         if(*who == '\0')
            goto jlogname;
      }else
jlogname:
         who = ok_vlook(LOGNAME);

      if ((name = fexpand(name, fexpm)) == NULL)
         goto jem1;
   }

   /* For at least substdate() users TODO -> eventloop tick */
   time_current_update(&time_current, FAL0);

   switch (which_protocol(orig_name = name, TRU1, TRU1, &name)) {
   case PROTO_FILE:
      isdevnull = ((n_poption & n_PO_BATCH_FLAG) &&
            !strcmp(name, n_path_devnull));
#ifdef HAVE_REALPATH
      do { /* TODO we need objects, goes away then */
# ifdef HAVE_REALPATH_NULL
         char *cp;

         if ((cp = realpath(name, NULL)) != NULL) {
            name = savestr(cp);
            (free)(cp);
         }
# else
         char cbuf[PATH_MAX];

         if (realpath(name, cbuf) != NULL)
            name = savestr(cbuf);
# endif
      } while (0);
#endif
      rv = 1;
      break;
   case PROTO_MAILDIR:
      shudclob = 1;
      rv = maildir_setfile(name, fm);
      goto jleave;
#ifdef HAVE_POP3
   case PROTO_POP3:
      shudclob = 1;
      rv = pop3_setfile(orig_name, fm);
      goto jleave;
#endif
   default:
      n_err(_("Cannot handle protocol: %s\n"), orig_name);
      goto jem1;
   }

   if ((ibuf = n_fopen_any(savecat("file://", name), "r", NULL)) == NULL) {
      int e = n_err_no;

      if ((fm & FEDIT_SYSBOX) && e == n_ERR_NOENT) {
         if (strcmp(who, ok_vlook(LOGNAME)) && getpwnam(who) == NULL) {
            n_err(_("%s is not a user of this system\n"),
               n_shexp_quote_cp(who, FAL0));
            goto jem2;
         }
         if (!(n_poption & n_PO_QUICKRUN_MASK) && ok_blook(bsdcompat))
            n_err(_("No mail for %s\n"), who);
      }
      if (fm & FEDIT_NEWMAIL)
         goto jleave;

      mb.mb_type = MB_VOID;
      if (ok_blook(emptystart)) {
         if (!(n_poption & n_PO_QUICKRUN_MASK) && !ok_blook(bsdcompat))
            n_perr(name, e);
         /* We must avoid returning -1 and causing program exit */
         rv = 1;
         goto jleave;
      }
      n_perr(name, e);
      goto jem1;
   }

   if (fstat(fileno(ibuf), &stb) == -1) {
      if (fm & FEDIT_NEWMAIL)
         goto jleave;
      n_perr(_("fstat"), 0);
      goto jem1;
   }

   if (S_ISREG(stb.st_mode) || isdevnull) {
      /* EMPTY */
   } else {
      if (fm & FEDIT_NEWMAIL)
         goto jleave;
      n_err_no = S_ISDIR(stb.st_mode) ? n_ERR_ISDIR : n_ERR_INVAL;
      n_perr(name, 0);
      goto jem1;
   }

   if (shudclob && !(fm & FEDIT_NEWMAIL) && !quit(FAL0))
      goto jem2;

   hold_sigs();

#ifdef HAVE_SOCKETS
   if (!(fm & FEDIT_NEWMAIL) && mb.mb_sock.s_fd >= 0)
      sclose(&mb.mb_sock); /* TODO sorry? VMAILFS->close(), thank you */
#endif

   /* TODO There is no intermediate VOID box we've switched to: name may
    * TODO point to the same box that we just have written, so any updates
    * TODO we won't see!  Reopen again in this case.  RACY! Goes with VOID! */
   /* TODO In addition: in case of compressed/hook boxes we lock a temporary! */
   /* TODO We may uselessly open twice but quit() doesn't say whether we were
    * TODO modified so we can't tell: Mailbox::is_modified() :-(( */
   if (/*shudclob && !(fm & FEDIT_NEWMAIL) &&*/ !strcmp(name, mailname)) {
      name = mailname;
      Fclose(ibuf);

      if ((ibuf = n_fopen_any(name, "r", NULL)) == NULL ||
            fstat(fileno(ibuf), &stb) == -1 ||
            (!S_ISREG(stb.st_mode) && !isdevnull)) {
         n_perr(name, 0);
         rele_sigs();
         goto jem2;
      }
   }

   /* Copy the messages into /tmp and set pointers */
   if (!(fm & FEDIT_NEWMAIL)) {
      if (isdevnull) {
         mb.mb_type = MB_VOID;
         mb.mb_perm = 0;
      } else {
         mb.mb_type = MB_FILE;
         mb.mb_perm = (((n_poption & n_PO_R_FLAG) || (fm & FEDIT_RDONLY) ||
               access(name, W_OK) < 0) ? 0 : MB_DELE | MB_EDIT);
         if (shudclob) {
            if (mb.mb_itf) {
               fclose(mb.mb_itf);
               mb.mb_itf = NULL;
            }
            if (mb.mb_otf) {
               fclose(mb.mb_otf);
               mb.mb_otf = NULL;
            }
         }
      }
      shudclob = 1;
      if (fm & FEDIT_SYSBOX)
         n_pstate &= ~n_PS_EDIT;
      else
         n_pstate |= n_PS_EDIT;
      initbox(name);
      offset = 0;
   } else {
      fseek(mb.mb_otf, 0L, SEEK_END);
      /* TODO Doing this without holding a lock is.. And not err checking.. */
      fseek(ibuf, mailsize, SEEK_SET);
      offset = mailsize;
      omsgCount = msgCount;
   }

   if (isdevnull)
      lckfp = (FILE*)-1;
   else if (!(n_pstate & n_PS_EDIT))
      lckfp = n_dotlock(name, fileno(ibuf), FLT_READ, offset,0,
            (fm & FEDIT_NEWMAIL ? 0 : UIZ_MAX));
   else if (n_file_lock(fileno(ibuf), FLT_READ, offset,0,
         (fm & FEDIT_NEWMAIL ? 0 : UIZ_MAX)))
      lckfp = (FILE*)-1;

   if (lckfp == NULL) {
      if (!(fm & FEDIT_NEWMAIL)) {
         char const *emsg = (n_pstate & n_PS_EDIT)
               ? N_("Unable to lock mailbox, aborting operation")
               : N_("Unable to (dot) lock mailbox, aborting operation");
         n_perr(V_(emsg), 0);
      }
      rele_sigs();
      if (!(fm & FEDIT_NEWMAIL))
         goto jem1;
      goto jleave;
   }

   mailsize = fsize(ibuf);

   /* TODO This is too simple minded?  We should regenerate an index file
    * TODO to be able to truly tell whether *anything* has changed! */
   if ((fm & FEDIT_NEWMAIL) && UICMP(z, mailsize, <=, offset)) {
      rele_sigs();
      goto jleave;
   }
   setptr(ibuf, offset);
   setmsize(msgCount);
   if ((fm & FEDIT_NEWMAIL) && mb.mb_sorted) {
      mb.mb_threaded = 0;
      c_sort((void*)-1);
   }

   Fclose(ibuf);
   ibuf = NULL;
   if (lckfp != NULL && lckfp != (FILE*)-1) {
      Pclose(lckfp, FAL0);
      /*lckfp = NULL;*/
   }

   if (!(fm & FEDIT_NEWMAIL)) {
      n_pstate &= ~n_PS_SAW_COMMAND;
      n_pstate |= n_PS_SETFILE_OPENED;
   }

   rele_sigs();

   rv = (msgCount == 0);
   if(rv)
      n_err_no = n_ERR_NODATA;

   if(n_poption & n_PO_EXISTONLY)
      goto jleave;

   if(rv){
      if(!(n_pstate & n_PS_EDIT) || (fm & FEDIT_NEWMAIL)){
         if(!(fm & FEDIT_NEWMAIL)){
            if (!ok_blook(emptystart))
               n_err(_("No mail for %s\n"), who);
         }
         goto jleave;
      }
   }

   if(fm & FEDIT_NEWMAIL)
      newmailinfo(omsgCount);
jleave:
   if (ibuf != NULL) {
      Fclose(ibuf);
      if (lckfp != NULL && lckfp != (FILE*)-1)
         Pclose(lckfp, FAL0);
   }
   NYD_LEAVE;
   return rv;
jem2:
   mb.mb_type = MB_VOID;
jem1:
   n_err_no = n_ERR_NOTOBACCO;
   rv = -1;
   goto jleave;
}

FL int
newmailinfo(int omsgCount)
{
   int mdot, i;
   NYD_ENTER;

   for (i = 0; i < omsgCount; ++i)
      message[i].m_flag &= ~MNEWEST;

   if (msgCount > omsgCount) {
      for (i = omsgCount; i < msgCount; ++i)
         message[i].m_flag |= MNEWEST;
      fprintf(n_stdout, _("New mail has arrived.\n"));
      if ((i = msgCount - omsgCount) == 1)
         fprintf(n_stdout, _("Loaded 1 new message.\n"));
      else
         fprintf(n_stdout, _("Loaded %d new messages.\n"), i);
   } else
      fprintf(n_stdout, _("Loaded %d messages.\n"), msgCount);

   temporary_folder_hook_check(TRU1);

   mdot = getmdot(1);

   if (ok_blook(header))
      print_headers(omsgCount + 1, msgCount, FAL0);
   NYD_LEAVE;
   return mdot;
}

FL void
setmsize(int sz)
{
   NYD_ENTER;
   if (n_msgvec != NULL)
      free(n_msgvec);
   n_msgvec = scalloc(sz + 1, sizeof *n_msgvec);
   NYD_LEAVE;
}

FL void
print_header_summary(char const *Larg)
{
   size_t bot, top, i, j;
   NYD_ENTER;

   if (Larg != NULL) {
      /* Avoid any messages XXX add a make_mua_silent() and use it? */
      if ((n_poption & (n_PO_VERB | n_PO_EXISTONLY)) == n_PO_EXISTONLY) {
         n_stdout = freopen(n_path_devnull, "w", stdout);
         n_stderr = freopen(n_path_devnull, "w", stderr);
      }
      assert(n_msgvec != NULL);
      i = (getmsglist(/*TODO make const */n_UNCONST(Larg), n_msgvec, 0) <= 0);
      if (n_poption & n_PO_EXISTONLY) {
         n_exit_status = (int)i;
         goto jleave;
      }
      if (i)
         goto jleave;
      for (bot = msgCount, top = 0, i = 0; (j = n_msgvec[i]) != 0; ++i) {
         if (bot > j)
            bot = j;
         if (top < j)
            top = j;
      }
   } else
      bot = 1, top = msgCount;
   print_headers(bot, top, (Larg != NULL)); /* TODO should take iterator!! */
jleave:
   NYD_LEAVE;
}

FL void
n_folder_announce(enum n_announce_flags af){
   int vec[2], mdot;
   NYD_ENTER;

   mdot = (mb.mb_type == MB_VOID) ? 1 : getmdot(0);
   dot = &message[mdot - 1];

   if(af != n_ANNOUNCE_NONE && ok_blook(header) &&
         ((af & n_ANNOUNCE_MAIN_CALL) ||
          ((af & n_ANNOUNCE_CHANGE) && !ok_blook(posix))))
      af |= n_ANNOUNCE_STATUS | n__ANNOUNCE_HEADER;

   if(af & n_ANNOUNCE_STATUS){
      a_folder_info();
      af |= n__ANNOUNCE_ANY;
   }

   if(af & n__ANNOUNCE_HEADER){
      if(!(af & n_ANNOUNCE_MAIN_CALL) && ok_blook(bsdannounce))
         n_OBSOLETE(_("*bsdannounce* is now default behaviour"));
      vec[0] = mdot;
      vec[1] = 0;
      print_header_group(vec); /* XXX errors? */
      af |= n__ANNOUNCE_ANY;
   }

   if(af & n__ANNOUNCE_ANY)
      fflush(n_stdout);
   NYD_LEAVE;
}

FL int
getmdot(int nmail)
{
   struct message *mp;
   char *cp;
   int mdot;
   enum mflag avoid = MHIDDEN | MDELETED;
   NYD_ENTER;

   if (!nmail) {
      if (ok_blook(autothread)) {
         n_OBSOLETE(_("please use *autosort=thread* instead of *autothread*"));
         c_thread(NULL);
      } else if ((cp = ok_vlook(autosort)) != NULL) {
         if (mb.mb_sorted != NULL)
            free(mb.mb_sorted);
         mb.mb_sorted = sstrdup(cp);
         c_sort(NULL);
      }
   }
   if (mb.mb_type == MB_VOID) {
      mdot = 1;
      goto jleave;
   }

   if (nmail)
      for (mp = message; PTRCMP(mp, <, message + msgCount); ++mp)
         if ((mp->m_flag & (MNEWEST | avoid)) == MNEWEST)
            break;

   if (!nmail || PTRCMP(mp, >=, message + msgCount)) {
      if (mb.mb_threaded) {
         for (mp = threadroot; mp != NULL; mp = next_in_thread(mp))
            if ((mp->m_flag & (MNEW | avoid)) == MNEW)
               break;
      } else {
         for (mp = message; PTRCMP(mp, <, message + msgCount); ++mp)
            if ((mp->m_flag & (MNEW | avoid)) == MNEW)
               break;
      }
   }

   if ((mb.mb_threaded ? (mp == NULL) : PTRCMP(mp, >=, message + msgCount))) {
      if (mb.mb_threaded) {
         for (mp = threadroot; mp != NULL; mp = next_in_thread(mp))
            if (mp->m_flag & MFLAGGED)
               break;
      } else {
         for (mp = message; PTRCMP(mp, <, message + msgCount); ++mp)
            if (mp->m_flag & MFLAGGED)
               break;
      }
   }

   if ((mb.mb_threaded ? (mp == NULL) : PTRCMP(mp, >=, message + msgCount))) {
      if (mb.mb_threaded) {
         for (mp = threadroot; mp != NULL; mp = next_in_thread(mp))
            if (!(mp->m_flag & (MREAD | avoid)))
               break;
      } else {
         for (mp = message; PTRCMP(mp, <, message + msgCount); ++mp)
            if (!(mp->m_flag & (MREAD | avoid)))
               break;
      }
   }

   if (nmail &&
         (mb.mb_threaded ? (mp != NULL) : PTRCMP(mp, <, message + msgCount)))
      mdot = (int)PTR2SIZE(mp - message + 1);
   else if (ok_blook(showlast)) {
      if (mb.mb_threaded) {
         for (mp = this_in_thread(threadroot, -1); mp;
               mp = prev_in_thread(mp))
            if (!(mp->m_flag & avoid))
               break;
         mdot = (mp != NULL) ? (int)PTR2SIZE(mp - message + 1) : msgCount;
      } else {
         for (mp = message + msgCount - 1; mp >= message; --mp)
            if (!(mp->m_flag & avoid))
               break;
         mdot = (mp >= message) ? (int)PTR2SIZE(mp - message + 1) : msgCount;
      }
   } else if (!nmail &&
         (mb.mb_threaded ? (mp != NULL) : PTRCMP(mp, <, message + msgCount)))
      mdot = (int)PTR2SIZE(mp - message + 1);
   else if (mb.mb_threaded) {
      for (mp = threadroot; mp; mp = next_in_thread(mp))
         if (!(mp->m_flag & avoid))
            break;
      mdot = (mp != NULL) ? (int)PTR2SIZE(mp - message + 1) : 1;
   } else {
      for (mp = message; PTRCMP(mp, <, message + msgCount); ++mp)
         if (!(mp->m_flag & avoid))
            break;
      mdot = PTRCMP(mp, <, message + msgCount)
            ? (int)PTR2SIZE(mp - message + 1) : 1;
   }
jleave:
   NYD_LEAVE;
   return mdot;
}

FL void
initbox(char const *name)
{
   char *tempMesg;
   NYD_ENTER;

   if (mb.mb_type != MB_VOID)
      n_strscpy(prevfile, mailname, PATH_MAX);

   /* TODO name always NE mailname (but goes away for objects anyway)
    * TODO Well, not true no more except that in parens */
   _update_mailname((name != mailname) ? name : NULL);

   if ((mb.mb_otf = Ftmp(&tempMesg, "tmpmbox", OF_WRONLY | OF_HOLDSIGS)) ==
         NULL) {
      n_perr(_("temporary mail message file"), 0);
      exit(n_EXIT_ERR);
   }
   if ((mb.mb_itf = safe_fopen(tempMesg, "r", NULL)) == NULL) {
      n_perr(_("temporary mail message file"), 0);
      exit(n_EXIT_ERR);
   }
   Ftmp_release(&tempMesg);

   message_reset();
   mb.mb_active = MB_NONE;
   mb.mb_threaded = 0;
   if (mb.mb_sorted != NULL) {
      free(mb.mb_sorted);
      mb.mb_sorted = NULL;
   }
   dot = prevdot = threadroot = NULL;
   n_pstate &= ~n_PS_DID_PRINT_DOT;
   NYD_LEAVE;
}

FL char const *
n_folder_query(void){
   struct n_string s, *sp = &s;
   char *cp;
   char const *rv;
   bool_t err;
   NYD_ENTER;

   sp = n_string_creat_auto(sp);

   /* *folder* is linked with *folder_resolved*: we only use the latter */
   for(err = FAL0;;){
      if((rv = ok_vlook(folder_resolved)) != NULL)
         break;

      /* POSIX says:
       *    If directory does not start with a <slash> ('/'), the contents
       *    of HOME shall be prefixed to it.
       * And:
       *    If folder is unset or set to null, [.] filenames beginning with
       *    '+' shall refer to files in the current directory.
       * We may have the result already */
      rv = n_empty;
      err = FAL0;

      if((cp = ok_vlook(folder)) == NULL)
         goto jset;

      /* Expand the *folder*; skip %: prefix for simplicity of use */
      if(cp[0] == '%' && cp[1] == ':')
         cp += 2;
      if((err = (cp = fexpand(cp, FEXP_NSPECIAL | FEXP_NFOLDER | FEXP_NSHELL)
            ) == NULL) || *cp == '\0')
         goto jset;

      switch(which_protocol(cp, FAL0, FAL0, NULL)){
      case PROTO_POP3:
         n_err(_("*folder* can't be set to a flat, read-only POP3 account\n"));
         err = TRU1;
         goto jset;
      default:
         /* Further expansion desired */
         break;
      }

      /* Prefix HOME as necessary */
      if(*cp != '/'){ /* XXX path_is_absolute() */
         size_t l1, l2;
         char const *home;

         home = ok_vlook(HOME);
         l1 = strlen(home);
         l2 = strlen(cp);

         sp = n_string_reserve(sp, l1 + 1 + l2 +1);
         sp = n_string_push_buf(sp, home, l1);
         sp = n_string_push_c(sp, '/');
         sp = n_string_push_buf(sp, cp, l2);
         cp = n_string_cp(sp);
         sp = n_string_drop_ownership(sp);
      }

      rv = cp;

      /* TODO Since our visual mailname is resolved via realpath(3) if available
       * TODO to avoid that we loose track of our currently open folder in case
       * TODO we chdir away, but still checks the leading path portion against
       * TODO n_folder_query() to be able to abbreviate to the +FOLDER syntax if
       * TODO possible, we need to realpath(3) the folder, too */
#ifdef HAVE_REALPATH
      assert(sp->s_len == 0 && sp->s_dat == NULL);
# ifndef HAVE_REALPATH_NULL
      sp = n_string_reserve(sp, PATH_MAX +1);
# endif

      if((sp->s_dat = realpath(cp, sp->s_dat)) != NULL){
# ifdef HAVE_REALPATH_NULL
         n_string_cp(sp = n_string_assign_cp(sp, cp = sp->s_dat));
         (free)(cp);
# endif
         rv = sp->s_dat;
      }else if(n_err_no == n_ERR_NOENT)
         rv = cp;
      else{
         n_err(_("Can't canonicalize *folder*: %s\n"),
            n_shexp_quote_cp(cp, FAL0));
         err = TRU1;
         rv = n_empty;
      }
      sp = n_string_drop_ownership(sp);
#endif /* HAVE_REALPATH */

      /* Always append a solidus to our result path upon success */
      if(!err){
         size_t i;

         if(rv[(i = strlen(rv)) - 1] != '/'){
            sp = n_string_reserve(sp, i + 1 +1);
            sp = n_string_push_buf(sp, rv, i);
            sp = n_string_push_c(sp, '/');
            rv = n_string_cp(sp);
            sp = n_string_drop_ownership(sp);
         }
      }

jset:
      n_PS_ROOT_BLOCK(ok_vset(folder_resolved, rv));
   }

   if(err){
      n_err(_("*folder* is not resolvable, using CWD\n"));
      assert(rv != NULL && *rv == '\0');
   }
   NYD_LEAVE;
   return rv;
}

FL int
n_folder_mbox_prepare_append(FILE *fout, struct stat *st_or_null){
   /* TODO n_folder_mbox_prepare_append -> Mailbox->append() */
   struct stat stb;
   char buf[2];
   bool_t needsep;
   int rv;
   NYD2_ENTER;

   if(fseek(fout, -2L, SEEK_END)){
      rv = n_err_no;

      if(st_or_null == NULL){
         st_or_null = &stb;
         if(fstat(fileno(fout), st_or_null))
            goto jerrno;
      }

      if(st_or_null->st_size >= 2)
         goto jleave;
      if(st_or_null->st_size == 0){
         rv = n_ERR_NONE;
         goto jleave;
      }
      if(fseek(fout, -1L, SEEK_END))
         goto jerrno;
   }

   rv = n_ERR_NONE;

   needsep = FAL0;
   switch(fread(buf, sizeof *buf, 2, fout)){
   case 2:
      if(buf[1] != '\n')
         needsep = TRU1;
      break;
   case 1:
      if(buf[0] != '\n')
         needsep = TRU1;
      break;
   default:
      if(ferror(fout))
         goto jerrno;
      break;
   }

   if(fflush(fout) || (needsep && putc('\n', fout) == EOF))
jerrno:
      rv = n_err_no;
jleave:
   NYD2_LEAVE;
   return rv;
}

/* s-it-mode */