Review: mime.c; tweak mime.types handling..

[s-mailx.git] / mime.c

/*@ S-nail - a mail user agent derived from Berkeley Mail.
 *@ MIME support functions.
 *
 * Copyright (c) 2000-2004 Gunnar Ritter, Freiburg i. Br., Germany.
 * Copyright (c) 2012 - 2014 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
 */
/*
 * Copyright (c) 2000
 * Gunnar Ritter.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by Gunnar Ritter
 *    and his contributors.
 * 4. Neither the name of Gunnar Ritter nor the names of his contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY GUNNAR RITTER 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 GUNNAR RITTER 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.
 */

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

#define _CHARSET()   ((_cs_iter != NULL) ? _cs_iter : charset_get_8bit())

struct mtnode {
   struct mtnode  *mt_next;
   size_t         mt_mtlen;   /* Length of MIME type string */
   char           mt_line[VFIELD_SIZE(8)];
};

static char const * const _mt_sources[] = {
   /* XXX Order fixed due to *mimetypes-load-control* handling! */
   MIME_TYPES_USR, MIME_TYPES_SYS, NULL
},
                  * const _mt_bltin[] = {
#include "mime_types.h"
   NULL
};

struct mtnode     *_mt_list;
char              *_cs_iter_base, *_cs_iter;

/* Initialize MIME type list */
static void             _mt_init(void);
static void             __mt_add_line(char const *line, struct mtnode **tail);

/* Is 7-bit enough? */
#ifdef HAVE_ICONV
static bool_t           _has_highbit(char const *s);
static bool_t           _name_highbit(struct name *np);
#endif

/* Get the conversion that matches *encoding* */
static enum conversion  _conversion_by_encoding(void);

/* fwrite(3) while checking for displayability */
static ssize_t          _fwrite_td(struct str const *input, enum tdflags flags,
                           struct str *rest, struct quoteflt *qf);

static size_t           delctrl(char *cp, size_t sz);

static int              is_this_enc(char const *line, char const *encoding);

/* Convert header fields to RFC 1522 format and write to the file fo */
static size_t           mime_write_tohdr(struct str *in, FILE *fo);

/* Write len characters of the passed string to the passed file, doing charset
 * and header conversion */
static size_t           convhdra(char const *str, size_t len, FILE *fp);

/* Write an address to a header field */
static size_t           mime_write_tohdr_a(struct str *in, FILE *f);

/* Append to buf, handling resizing */
static void             addstr(char **buf, size_t *sz, size_t *pos,
                           char const *str, size_t len);

static void             addconv(char **buf, size_t *sz, size_t *pos,
                           char const *str, size_t len);

static void
_mt_init(void)
{
   struct mtnode *tail = NULL;
   char *line = NULL; /* TODO line pool */
   size_t linesize = 0;
   ui32_t idx, idx_ok;
   char const *ccp, * const *srcs;
   FILE *fp;
   NYD_ENTER;

   if ((ccp = ok_vlook(mimetypes_load_control)) == NULL)
      idx_ok = (ui32_t)-1;
   else for (idx_ok = 0; *ccp != '\0'; ++ccp)
      switch (*ccp) {
      case 'S':
      case 's':
         idx_ok |= 1 << 1;
         break;
      case 'U':
      case 'u':
         idx_ok |= 1 << 0;
         break;
      default:
         /* XXX bad *mimetypes-load-control*; log error? */
         break;
      }

   for (idx = 1, srcs = _mt_sources; *srcs != NULL; idx <<= 1, ++srcs) {
      if (!(idx & idx_ok) || (ccp = file_expand(*srcs)) == NULL)
         continue;
      if ((fp = Fopen(ccp, "r")) == NULL) {
         /*fprintf(stderr, tr(176, "Cannot open %s\n"), fn);*/
         continue;
      }
      while (fgetline(&line, &linesize, NULL, NULL, fp, 0))
         __mt_add_line(line, &tail);
      Fclose(fp);
   }
   if (line != NULL)
      free(line);

   for (srcs = _mt_bltin; *srcs != NULL; ++srcs)
      __mt_add_line(*srcs, &tail);
   NYD_LEAVE;
}

static void
__mt_add_line(char const *line, struct mtnode **tail) /* XXX diag? dups!*/
{
   char const *typ;
   size_t tlen, elen;
   struct mtnode *mtn;
   NYD_ENTER;

   if (!alphachar(*line))
      goto jleave;

   typ = line;
   while (!blankchar(*line) && *line != '\0')
      ++line;
   if (*line == '\0')
      goto jleave;
   tlen = PTR2SIZE(line - typ);

   while (blankchar(*line) && *line != '\0')
      ++line;

   if (*line == '\0')
      goto jleave;
   elen = strlen(line);
   if (line[elen - 1] == '\n') {
      if (--elen > 0 && line[elen - 1] == '\r')
         --elen;
      if (elen == 0)
         goto jleave;
   }

   mtn = smalloc(sizeof(struct mtnode) -
         VFIELD_SIZEOF(struct mtnode, mt_line) + tlen + 1 + elen +1);
   if (*tail != NULL)
      (*tail)->mt_next = mtn;
   else
      _mt_list = mtn;
   *tail = mtn;
   mtn->mt_next = NULL;
   mtn->mt_mtlen = tlen;
   memcpy(mtn->mt_line, typ, tlen);
   mtn->mt_line[tlen] = '\0';
   ++tlen;
   memcpy(mtn->mt_line + tlen, line, elen);
   tlen += elen;
   mtn->mt_line[tlen] = '\0';
jleave:
   NYD_LEAVE;
}

#ifdef HAVE_ICONV
static bool_t
_has_highbit(char const *s)
{
   bool_t rv = TRU1;
   NYD_ENTER;

   if (s) {
      do
         if ((ui8_t)*s & 0x80)
            goto jleave;
      while (*s++ != '\0');
   }
   rv = FAL0;
jleave:
   NYD_LEAVE;
   return rv;
}

static bool_t
_name_highbit(struct name *np)
{
   bool_t rv = TRU1;
   NYD_ENTER;

   while (np) {
      if (_has_highbit(np->n_name) || _has_highbit(np->n_fullname))
         goto jleave;
      np = np->n_flink;
   }
   rv = FAL0;
jleave:
   NYD_LEAVE;
   return rv;
}
#endif /* HAVE_ICONV */

static enum conversion
_conversion_by_encoding(void)
{
   char const *cp;
   enum conversion ret;
   NYD_ENTER;

   if ((cp = ok_vlook(encoding)) == NULL)
      ret = MIME_DEFAULT_ENCODING;
   else if (!strcmp(cp, "quoted-printable"))
      ret = CONV_TOQP;
   else if (!strcmp(cp, "8bit"))
      ret = CONV_8BIT;
   else if (!strcmp(cp, "base64"))
      ret = CONV_TOB64;
   else {
      fprintf(stderr, tr(177, "Warning: invalid encoding %s, using base64\n"),
         cp);
      ret = CONV_TOB64;
   }
   NYD_LEAVE;
   return ret;
}

static ssize_t
_fwrite_td(struct str const *input, enum tdflags flags, struct str *rest,
   struct quoteflt *qf)
{
   /* TODO note: after send/MIME layer rewrite we will have a string pool
    * TODO so that memory allocation count drops down massively; for now,
    * TODO v14.* that is, we pay a lot & heavily depend on the allocator */
   /* TODO well if we get a broken pipe here, and it happens to
    * TODO happen pretty easy when sleeping in a full pipe buffer,
    * TODO then the current codebase performs longjump away;
    * TODO this leaves memory leaks behind ('think up to 3 per,
    * TODO dep. upon alloca availability).  For this to be fixed
    * TODO we either need to get rid of the longjmp()s (tm) or
    * TODO the storage must come from the outside or be tracked
    * TODO in a carrier struct.  Best both.  But storage reuse
    * TODO would be a bigbig win besides */
   /* *input* _may_ point to non-modifyable buffer; but even then it only
    * needs to be dup'ed away if we have to transform the content */
   struct str in, out;
   ssize_t rv;
   NYD_ENTER;
   UNUSED(rest);

   in = *input;
   out.s = NULL;
   out.l = 0;

#ifdef HAVE_ICONV
   if ((flags & TD_ICONV) && iconvd != (iconv_t)-1) {
      char *buf = NULL;

      if (rest != NULL && rest->l > 0) {
         in.l = rest->l + input->l;
         in.s = buf = smalloc(in.l +1);
         memcpy(in.s, rest->s, rest->l);
         memcpy(in.s + rest->l, input->s, input->l);
         rest->l = 0;
      }

      if (n_iconv_str(iconvd, &out, &in, &in, TRU1) != 0 && rest != NULL &&
            in.l > 0) {
         /* Incomplete multibyte at EOF is special */
         if (flags & _TD_EOF) {
            out.s = srealloc(out.s, out.l + 4);
            /* TODO 0xFFFD out.s[out.l++] = '[';*/
            out.s[out.l++] = '?'; /* TODO 0xFFFD !!! */
            /* TODO 0xFFFD out.s[out.l++] = ']';*/
         } else
            n_str_add(rest, &in);
      }
      in = out;
      out.s = NULL;
      flags &= ~_TD_BUFCOPY;

      if (buf != NULL)
         free(buf);
   }
#endif

   if (flags & TD_ISPR)
      makeprint(&in, &out);
   else if (flags & _TD_BUFCOPY)
      n_str_dup(&out, &in);
   else
      out = in;
   if (flags & TD_DELCTRL)
      out.l = delctrl(out.s, out.l);

   rv = quoteflt_push(qf, out.s, out.l);

   if (out.s != in.s)
      free(out.s);
   if (in.s != input->s)
      free(in.s);
   NYD_LEAVE;
   return rv;
}

static size_t
delctrl(char *cp, size_t sz)
{
   size_t x = 0, y = 0;
   NYD_ENTER;

   while (x < sz) {
      if (!cntrlchar(cp[x]))
         cp[y++] = cp[x];
      ++x;
   }
   NYD_LEAVE;
   return y;
}

static int
is_this_enc(char const *line, char const *encoding)
{
   int rv, c, quoted = 0;
   NYD_ENTER;

   if (*line == '"')
      quoted = 1, ++line;
   rv = 0;
   while (*line != '\0' && *encoding)
      if ((c = *line++, lowerconv(c) != *encoding++))
         goto jleave;
   rv = 1;
   if (quoted && *line == '"')
      goto jleave;
   if (*line == '\0' || whitechar(*line))
      goto jleave;
   rv = 0;
jleave:
   NYD_LEAVE;
   return rv;
}

static size_t
mime_write_tohdr(struct str *in, FILE *fo) /* TODO rewrite - FAST! */
{
   struct str cin, cout;
   char buf[B64_LINESIZE +1]; /* (No CR/LF used) */
   char const *charset7, *charset, *upper, *wbeg, *wend, *lastspc,
      *lastwordend = NULL;
   size_t sz = 0, col = 0, quoteany, wr, charsetlen,
      maxcol = 65 /* there is the header field's name, too */;
   bool_t highbit, mustquote, broken;
   NYD_ENTER;

   charset7 = charset_get_7bit();
   charset = _CHARSET();
   wr = strlen(charset7);
   charsetlen = strlen(charset);
   charsetlen = MAX(charsetlen, wr);
   upper = in->s + in->l;

   /* xxx note this results in too much hits since =/? force quoting even
    * xxx if they don't form =? etc. */
   quoteany = mime_cte_mustquote(in->s, in->l, TRU1);

   highbit = FAL0;
   if (quoteany != 0)
      for (wbeg = in->s; wbeg < upper; ++wbeg)
         if ((ui8_t)*wbeg & 0x80)
            highbit = TRU1;

   if (quoteany << 1 > in->l) {
      /* Print the entire field in base64 */
      for (wbeg = in->s; wbeg < upper; wbeg = wend) {
         wend = upper;
         cin.s = UNCONST(wbeg);
         for (;;) {
            cin.l = PTR2SIZE(wend - wbeg);
            if (cin.l * 4/3 + 7 + charsetlen < maxcol - col) {
               cout.s = buf;
               cout.l = sizeof buf;
               wr = fprintf(fo, "=?%s?B?%s?=", (highbit ? charset : charset7),
                     b64_encode(&cout, &cin, B64_BUF)->s);
               sz += wr;
               col += wr;
               if (wend < upper) {
                  fwrite("\n ", sizeof(char), 2, fo);
                  sz += 2;
                  col = 0;
                  maxcol = 76;
               }
               break;
            } else {
               if (col) {
                  fprintf(fo, "\n ");
                  sz += 2;
                  col = 0;
                  maxcol = 76;
               } else
                  wend -= 4;
            }
         }
      }
   } else {
      /* Print the field word-wise in quoted-printable */
      broken = FAL0;
      for (wbeg = in->s; wbeg < upper; wbeg = wend) {
         lastspc = NULL;
         while (wbeg < upper && whitechar(*wbeg)) {
            lastspc = lastspc ? lastspc : wbeg;
            ++wbeg;
            ++col;
            broken = FAL0;
         }
         if (wbeg == upper) {
            if (lastspc)
               while (lastspc < wbeg) {
                  putc(*lastspc&0377, fo);
                  ++lastspc;
                  ++sz;
               }
            break;
         }

         if (lastspc != NULL)
            broken = FAL0;
         highbit = FAL0;
         for (wend = wbeg; wend < upper && !whitechar(*wend); ++wend)
            if ((ui8_t)*wend & 0x80)
               highbit = TRU1;
         mustquote = (mime_cte_mustquote(wbeg, PTR2SIZE(wend - wbeg), TRU1)
               != 0);

         if (mustquote || broken ||
               (PTR2SIZE(wend - wbeg) >= 76-5 && quoteany)) {
            for (cout.s = NULL;;) {
               cin.s = UNCONST(lastwordend ?  lastwordend : wbeg);
               cin.l = PTR2SIZE(wend - cin.s);
               qp_encode(&cout, &cin, QP_ISHEAD);
               wr = cout.l + charsetlen + 7;
jqp_retest:
               if (col <= maxcol && wr <= maxcol - col) {
                  if (lastspc) {
                     /* TODO because we included the WS in the encoded str,
                      * TODO put SP only??
                      * TODO RFC: "any 'linear-white-space' that separates
                      * TODO a pair of adjacent 'encoded-word's is ignored" */
                     putc(' ', fo);
                     ++sz;
                     ++col;
                  }
                  fprintf(fo, "=?%s?Q?%.*s?=",
                     (highbit ? charset : charset7), (int)cout.l, cout.s);
                  sz += wr;
                  col += wr;
                  break;
               } else if (col > 1) {
                  /* TODO assuming SP separator, ignore *lastspc* !?? */
                  broken = TRU1;
                  if (lastspc != NULL) {
                     putc('\n', fo);
                     ++sz;
                     col = 0;
                  } else {
                     fputs("\n ", fo);
                     sz += 2;
                     col = 1;
                  }
                  maxcol = 76;
                  goto jqp_retest;
               } else {
                  for (;;) { /* XXX */
                     wend -= 4;
                     assert(wend > wbeg);
                     if (wr - 4 < maxcol)
                        break;
                     wr -= 4;
                  }
               }
            }
            if (cout.s != NULL)
               free(cout.s);
            lastwordend = wend;
         } else {
            if (col && PTR2SIZE(wend - wbeg) > maxcol - col) {
               putc('\n', fo);
               ++sz;
               col = 0;
               maxcol = 76;
               if (lastspc == NULL) {
                  putc(' ', fo);
                  ++sz;
                  --maxcol;
               } else
                  maxcol -= PTR2SIZE(wbeg - lastspc);
            }
            if (lastspc)
               while (lastspc < wbeg) {
                  putc(*lastspc&0377, fo);
                  ++lastspc;
                  ++sz;
               }
            wr = fwrite(wbeg, sizeof *wbeg, PTR2SIZE(wend - wbeg), fo);
            sz += wr;
            col += wr;
            lastwordend = NULL;
         }
      }
   }
   NYD_LEAVE;
   return sz;
}

static size_t
convhdra(char const *str, size_t len, FILE *fp)
{
#ifdef HAVE_ICONV
   struct str ciconv;
#endif
   struct str cin;
   size_t ret = 0;
   NYD_ENTER;

   cin.s = UNCONST(str);
   cin.l = len;
#ifdef HAVE_ICONV
   ciconv.s = NULL;
   if (iconvd != (iconv_t)-1) {
      ciconv.l = 0;
      if (n_iconv_str(iconvd, &ciconv, &cin, NULL, FAL0) != 0)
         goto jleave;
      cin = ciconv;
   }
#endif
   ret = mime_write_tohdr(&cin, fp);
#ifdef HAVE_ICONV
jleave:
   if (ciconv.s != NULL)
      free(ciconv.s);
#endif
   NYD_LEAVE;
   return ret;
}

static size_t
mime_write_tohdr_a(struct str *in, FILE *f)
{
   char const *cp, *lastcp;
   size_t sz = 0;
   NYD_ENTER;

   in->s[in->l] = '\0';
   lastcp = in->s;
   if ((cp = routeaddr(in->s)) != NULL && cp > lastcp) {
      sz += convhdra(lastcp, PTR2SIZE(cp - lastcp), f);
      lastcp = cp;
   } else
      cp = in->s;
   for ( ; *cp != '\0'; ++cp) {
      switch (*cp) {
      case '(':
         sz += fwrite(lastcp, 1, PTR2SIZE(cp - lastcp + 1), f);
         lastcp = ++cp;
         cp = skip_comment(cp);
         if (--cp > lastcp)
            sz += convhdra(lastcp, PTR2SIZE(cp - lastcp), f);
         lastcp = cp;
         break;
      case '"':
         while (*cp) {
            if (*++cp == '"')
               break;
            if (*cp == '\\' && cp[1] != '\0')
               cp++;
         }
         break;
      }
   }
   if (cp > lastcp)
      sz += fwrite(lastcp, 1, PTR2SIZE(cp - lastcp), f);
   NYD_LEAVE;
   return sz;
}

static void
addstr(char **buf, size_t *sz, size_t *pos, char const *str, size_t len)
{
   NYD_ENTER;
   *buf = srealloc(*buf, *sz += len);
   memcpy(&(*buf)[*pos], str, len);
   *pos += len;
   NYD_LEAVE;
}

static void
addconv(char **buf, size_t *sz, size_t *pos, char const *str, size_t len)
{
   struct str in, out;
   NYD_ENTER;

   in.s = UNCONST(str);
   in.l = len;
   mime_fromhdr(&in, &out, TD_ISPR | TD_ICONV);
   addstr(buf, sz, pos, out.s, out.l);
   free(out.s);
   NYD_LEAVE;
}

FL char const *
charset_get_7bit(void)
{
   char const *t;
   NYD_ENTER;

   if ((t = ok_vlook(charset_7bit)) == NULL)
      t = CHARSET_7BIT;
   NYD_LEAVE;
   return t;
}

FL char const *
charset_get_8bit(void)
{
   char const *t;
   NYD_ENTER;

   if ((t = ok_vlook(CHARSET_8BIT_OKEY)) == NULL)
      t = CHARSET_8BIT;
   NYD_LEAVE;
   return t;
}

FL char const *
charset_get_lc(void)
{
   char const *t;
   NYD_ENTER;

   if ((t = ok_vlook(ttycharset)) == NULL)
      t = CHARSET_8BIT;
   NYD_LEAVE;
   return t;
}

FL void
charset_iter_reset(char const *a_charset_to_try_first)
{
   char const *sarr[3];
   size_t sarrl[3], len;
   char *cp;
   NYD_ENTER;

   sarr[0] = a_charset_to_try_first;
#ifdef HAVE_ICONV
   if ((sarr[1] = ok_vlook(sendcharsets)) == NULL &&
         ok_blook(sendcharsets_else_ttycharset))
      sarr[1] = charset_get_lc();
#endif
   sarr[2] = charset_get_8bit();

   sarrl[2] = len = strlen(sarr[2]);
#ifdef HAVE_ICONV
   if ((cp = UNCONST(sarr[1])) != NULL)
      len += (sarrl[1] = strlen(cp));
   else
      sarrl[1] = 0;
   if ((cp = UNCONST(sarr[0])) != NULL)
      len += (sarrl[0] = strlen(cp));
   else
      sarrl[0] = 0;
#endif

   _cs_iter_base = cp = salloc(len + 1 + 1 +1);

#ifdef HAVE_ICONV
   if ((len = sarrl[0]) != 0) {
      memcpy(cp, sarr[0], len);
      cp[len] = ',';
      cp += ++len;
   }
   if ((len = sarrl[1]) != 0) {
      memcpy(cp, sarr[1], len);
      cp[len] = ',';
      cp += ++len;
   }
#endif
   len = sarrl[2];
   memcpy(cp, sarr[2], len);
   cp[len] = '\0';
   _cs_iter = NULL;
   NYD_LEAVE;
}

FL char const *
charset_iter_next(void)
{
   char const *rv;
   NYD_ENTER;

   rv = _cs_iter = n_strsep(&_cs_iter_base, ',', TRU1);
   NYD_LEAVE;
   return rv;
}

FL char const *
charset_iter_current(void)
{
   char const *rv;
   NYD_ENTER;

   rv = _cs_iter;
   NYD_LEAVE;
   return rv;
}

FL void
charset_iter_recurse(char *outer_storage[2]) /* TODO LEGACY FUN, REMOVE */
{
   NYD_ENTER;
   outer_storage[0] = _cs_iter_base;
   outer_storage[1] = _cs_iter;
   NYD_LEAVE;
}

FL void
charset_iter_restore(char *outer_storage[2]) /* TODO LEGACY FUN, REMOVE */
{
   NYD_ENTER;
   _cs_iter_base = outer_storage[0];
   _cs_iter = outer_storage[1];
   NYD_LEAVE;
}

#ifdef HAVE_ICONV
FL char const *
need_hdrconv(struct header *hp, enum gfield w)
{
   char const *ret = NULL;
   NYD_ENTER;

   if (w & GIDENT) {
      if (hp->h_from != NULL) {
         if (_name_highbit(hp->h_from))
            goto jneeds;
      } else if (_has_highbit(myaddrs(NULL)))
         goto jneeds;
      if (hp->h_organization) {
         if (_has_highbit(hp->h_organization))
            goto jneeds;
      } else if (_has_highbit(ok_vlook(ORGANIZATION)))
         goto jneeds;
      if (hp->h_replyto) {
         if (_name_highbit(hp->h_replyto))
            goto jneeds;
      } else if (_has_highbit(ok_vlook(replyto)))
         goto jneeds;
      if (hp->h_sender) {
         if (_name_highbit(hp->h_sender))
            goto jneeds;
      } else if (_has_highbit(ok_vlook(sender)))
         goto jneeds;
   }
   if ((w & GTO) && _name_highbit(hp->h_to))
      goto jneeds;
   if ((w & GCC) && _name_highbit(hp->h_cc))
      goto jneeds;
   if ((w & GBCC) && _name_highbit(hp->h_bcc))
      goto jneeds;
   if ((w & GSUBJECT) && _has_highbit(hp->h_subject))
jneeds:
      ret = _CHARSET();
   NYD_LEAVE;
   return ret;
}
#endif /* HAVE_ICONV */

FL enum mimeenc
mime_getenc(char *p)
{
   enum mimeenc rv;
   NYD_ENTER;

   if (is_this_enc(p, "7bit"))
      rv = MIME_7B;
   else if (is_this_enc(p, "8bit"))
      rv = MIME_8B;
   else if (is_this_enc(p, "base64"))
      rv = MIME_B64;
   else if (is_this_enc(p, "binary"))
      rv = MIME_BIN;
   else if (is_this_enc(p, "quoted-printable"))
      rv = MIME_QP;
   else
      rv = MIME_NONE;
   NYD_LEAVE;
   return rv;
}

FL char *
mime_getparam(char const *param, char *h)
{
   char *p = h, *q, *rv = NULL;
   int c;
   size_t sz;
   NYD_ENTER;

   sz = strlen(param);
   if (!whitechar(*p)) {
      c = '\0';
      while (*p && (*p != ';' || c == '\\')) {
         c = (c == '\\') ? '\0' : *p;
         ++p;
      }
      if (*p++ == '\0')
         goto jleave;
   }

   for (;;) {
      while (whitechar(*p))
         ++p;
      if (!ascncasecmp(p, param, sz)) {
         p += sz;
         while (whitechar(*p))
            ++p;
         if (*p++ == '=')
            break;
      }
      c = '\0';
      while (*p != '\0' && (*p != ';' || c == '\\')) {
         if (*p == '"' && c != '\\') {
            ++p;
            while (*p != '\0' && (*p != '"' || c == '\\')) {
               c = (c == '\\') ? '\0' : *p;
               ++p;
            }
            ++p;
         } else {
            c = (c == '\\') ? '\0' : *p;
            ++p;
         }
      }
      if (*p++ == '\0')
         goto jleave;
   }
   while (whitechar(*p))
      ++p;

   q = p;
   if (*p == '"') {
      p++;
      if ((q = strchr(p, '"')) == NULL)
         goto jleave;
   } else {
      while (*q != '\0' && !whitechar(*q) && *q != ';')
         ++q;
   }
   sz = PTR2SIZE(q - p);
   rv = salloc(q - p +1);
   memcpy(rv, p, sz);
   rv[sz] = '\0';
jleave:
   NYD_LEAVE;
   return rv;
}

FL char *
mime_get_boundary(char *h, size_t *len)
{
   char *q = NULL, *p;
   size_t sz;
   NYD_ENTER;

   if ((p = mime_getparam("boundary", h)) != NULL) {
      sz = strlen(p);
      if (len != NULL)
         *len = sz + 2;
      q = salloc(sz + 2 +1);
      q[0] = q[1] = '-';
      memcpy(q + 2, p, sz);
      *(q + sz + 2) = '\0';
   }
   NYD_LEAVE;
   return q;
}

FL char *
mime_create_boundary(void)
{
   char *bp;
   NYD_ENTER;

   bp = salloc(48);
   snprintf(bp, 48, "=_%011lu=-%s=_", (ul_it)time_current.tc_time,
      getrandstring(47 - (11 + 6)));
   NYD_LEAVE;
   return bp;
}

FL int
mime_classify_file(FILE *fp, char const **contenttype, char const **charset,
   int *do_iconv)
{
   /* TODO classify once only PLEASE PLEASE PLEASE */
   /* TODO BTW., after the MIME/send layer rewrite we could use a MIME
    * TODO boundary of "=-=-=" if we would add a B_ in EQ spirit to F_,
    * TODO and report that state to the outer world */
#define F_        "From "
#define F_SIZEOF  (sizeof(F_) -1)

   char f_buf[F_SIZEOF], *f_p = f_buf;
   enum {
      _CLEAN      = 0,     /* Plain RFC 2822 message */
      _NCTT       = 1<<0,  /* *contenttype == NULL */
      _ISTXT      = 1<<1,  /* *contenttype =~ text/ */
      _ISTXTCOK   = 1<<2,  /* _ISTXT + *mime-allow-text-controls* */
      _HIGHBIT    = 1<<3,  /* Not 7bit clean */
      _LONGLINES  = 1<<4,  /* MIME_LINELEN_LIMIT exceed. */
      _CTRLCHAR   = 1<<5,  /* Control characters seen */
      _HASNUL     = 1<<6,  /* Contains \0 characters */
      _NOTERMNL   = 1<<7,  /* Lacks a final newline */
      _TRAILWS    = 1<<8,  /* Blanks before NL */
      _FROM_      = 1<<9   /* ^From_ seen */
   } ctt = _CLEAN;
   enum conversion convert;
   ssize_t curlen;
   int c, lastc;
   NYD_ENTER;

   assert(ftell(fp) == 0x0l);

   *do_iconv = 0;

   if (*contenttype == NULL)
      ctt = _NCTT;
   else if (!ascncasecmp(*contenttype, "text/", 5))
      ctt = ok_blook(mime_allow_text_controls) ? _ISTXT | _ISTXTCOK : _ISTXT;
   convert = _conversion_by_encoding();

   if (fsize(fp) == 0)
      goto j7bit;

   /* We have to inspect the file content */
   for (curlen = 0, c = EOF;; ++curlen) {
      lastc = c;
      c = getc(fp);

      if (c == '\0') {
         ctt |= _HASNUL;
         if (!(ctt & _ISTXTCOK))
            break;
         continue;
      }
      if (c == '\n' || c == EOF) {
         if (curlen >= MIME_LINELEN_LIMIT)
            ctt |= _LONGLINES;
         if (c == EOF)
            break;
         if (blankchar(lastc))
            ctt |= _TRAILWS;
         f_p = f_buf;
         curlen = -1;
         continue;
      }
      /* A bit hairy is handling of \r=\x0D=CR.
       * RFC 2045, 6.7:
       * Control characters other than TAB, or CR and LF as parts of CRLF
       * pairs, must not appear.  \r alone does not force _CTRLCHAR below since
       * we cannot peek the next character.  Thus right here, inspect the last
       * seen character for if its \r and set _CTRLCHAR in a delayed fashion */
       /*else*/ if (lastc == '\r')
         ctt |= _CTRLCHAR;

      /* Control character? XXX this is all ASCII here */
      if (c < 0x20 || c == 0x7F) {
         /* RFC 2045, 6.7, as above ... */
         if (c != '\t' && c != '\r')
            ctt |= _CTRLCHAR;
         /* If there is a escape sequence in backslash notation defined for
          * this in ANSI X3.159-1989 (ANSI C89), don't treat it as a control
          * for real.  I.e., \a=\x07=BEL, \b=\x08=BS, \t=\x09=HT.  Don't follow
          * libmagic(1) in respect to \v=\x0B=VT.  \f=\x0C=NP; do ignore
          * \e=\x1B=ESC */
         if ((c >= '\x07' && c <= '\x0D') || c == '\x1B')
            continue;
         ctt |= _HASNUL; /* Force base64 */
         if (!(ctt & _ISTXTCOK))
            break;
      } else if ((ui8_t)c & 0x80) {
         ctt |= _HIGHBIT;
         /* TODO count chars with HIGHBIT? libmagic?
          * TODO try encode part - base64 if bails? */
         if (!(ctt & (_NCTT | _ISTXT))) { /* TODO _NCTT?? */
            ctt |= _HASNUL; /* Force base64 */
            break;
         }
      } else if (!(ctt & _FROM_) && UICMP(z, curlen, <, F_SIZEOF)) {
         *f_p++ = (char)c;
         if (UICMP(z, curlen, ==, F_SIZEOF - 1) &&
               PTR2SIZE(f_p - f_buf) == F_SIZEOF &&
               !memcmp(f_buf, F_, F_SIZEOF))
            ctt |= _FROM_;
      }
   }
   if (lastc != '\n')
      ctt |= _NOTERMNL;
   rewind(fp);

   if (ctt & _HASNUL) {
      convert = CONV_TOB64;
      /* Don't overwrite a text content-type to allow UTF-16 and such, but only
       * on request; else enforce what file(1)/libmagic(3) would suggest */
      if (ctt & _ISTXTCOK)
         goto jcharset;
      if (ctt & (_NCTT | _ISTXT))
         *contenttype = "application/octet-stream";
      if (*charset == NULL)
         *charset = "binary";
      goto jleave;
   }

   if (ctt & (_LONGLINES | _CTRLCHAR | _NOTERMNL | _TRAILWS | _FROM_)) {
      convert = CONV_TOQP;
      goto jstepi;
   }
   if (ctt & _HIGHBIT) {
jstepi:
      if (ctt & (_NCTT | _ISTXT))
         *do_iconv = ((ctt & _HIGHBIT) != 0);
   } else
j7bit:
      convert = CONV_7BIT;
   if (ctt & _NCTT)
      *contenttype = "text/plain";

   /* Not an attachment with specified charset? */
jcharset:
   if (*charset == NULL)
      *charset = (ctt & _HIGHBIT) ? _CHARSET() : charset_get_7bit();
jleave:
   NYD_LEAVE;
   return convert;
#undef F_
#undef F_SIZEOF
}

FL enum mimecontent
mime_classify_content_of_part(struct mimepart const *mip)
{
   enum mimecontent mc;
   char const *ct;
   NYD_ENTER;

   mc = MIME_UNKNOWN;
   ct = mip->m_ct_type_plain;

   if (!asccasecmp(ct, "application/octet-stream") &&
         mip->m_filename != NULL && ok_blook(mime_counter_evidence)) {
      ct = mime_classify_content_type_by_fileext(mip->m_filename);
      if (ct == NULL)
         /* TODO how about let *mime-counter-evidence* have
          * TODO a value, and if set, saving the attachment in
          * TODO a temporary file that mime_classify_file() can
          * TODO examine, and using MIME_TEXT if that gives us
          * TODO something that seems to be human readable?! */
         goto jleave;
   }
   if (strchr(ct, '/') == NULL) /* For compatibility with non-MIME */
      mc = MIME_TEXT;
   else if (!asccasecmp(ct, "text/plain"))
      mc = MIME_TEXT_PLAIN;
   else if (!asccasecmp(ct, "text/html"))
      mc = MIME_TEXT_HTML;
   else if (!ascncasecmp(ct, "text/", 5))
      mc = MIME_TEXT;
   else if (!asccasecmp(ct, "message/rfc822"))
      mc = MIME_822;
   else if (!ascncasecmp(ct, "message/", 8))
      mc = MIME_MESSAGE;
   else if (!asccasecmp(ct, "multipart/alternative"))
      mc = MIME_ALTERNATIVE;
   else if (!asccasecmp(ct, "multipart/digest"))
      mc = MIME_DIGEST;
   else if (!ascncasecmp(ct, "multipart/", 10))
      mc = MIME_MULTI;
   else if (!asccasecmp(ct, "application/x-pkcs7-mime") ||
         !asccasecmp(ct, "application/pkcs7-mime"))
      mc = MIME_PKCS7;
jleave:
   NYD_LEAVE;
   return mc;
}

FL char *
mime_classify_content_type_by_fileext(char const *name)
{
   char *content = NULL;
   struct mtnode *mtn;
   size_t nlen;
   NYD_ENTER;

   if ((name = strrchr(name, '.')) == NULL || *++name == '\0')
      goto jleave;

   if (_mt_list == NULL)
      _mt_init();

   nlen = strlen(name);
   for (mtn = _mt_list; mtn != NULL; mtn = mtn->mt_next) {
      char const *ext = mtn->mt_line + mtn->mt_mtlen + 1,
         *cp = ext;
      do {
         while (!whitechar(*cp) && *cp != '\0')
            ++cp;
         /* Better to do case-insensitive comparison on extension, since the
          * RFC doesn't specify case of attribute values? */
         if (nlen == PTR2SIZE(cp - ext) && !ascncasecmp(name, ext, nlen)) {
            content = savestrbuf(mtn->mt_line, mtn->mt_mtlen);
            goto jleave;
         }
         while (whitechar(*cp) && *cp != '\0')
            ++cp;
         ext = cp;
      } while (*ext != '\0');
   }
jleave:
   NYD_LEAVE;
   return content;
}

FL int
c_mimetypes(void *v)
{
   char **argv = v;
   struct mtnode *mtn;
   NYD_ENTER;

   if (*argv == NULL)
      goto jlist;
   if (argv[1] != NULL)
      goto jerr;
   if (!asccasecmp(*argv, "show"))
      goto jlist;
   if (!asccasecmp(*argv, "clear"))
      goto jclear;
jerr:
   fprintf(stderr, "Synopsis: mimetypes: %s\n",
      tr(418, "Either <show> (default) or <clear> the mime.types cache"));
   v = NULL;
jleave:
   NYD_LEAVE;
   return (v == NULL ? !STOP : !OKAY); /* xxx 1:bad 0:good -- do some */

jlist:   {
   FILE *fp;
   size_t l;

   if (_mt_list == NULL)
      _mt_init();

   if ((fp = Ftmp(NULL, "mimelist", OF_RDWR | OF_UNLINK | OF_REGISTER, 0600)) ==
         NULL) {
      perror("tmpfile");
      v = NULL;
      goto jleave;
   }

   for (l = 0, mtn = _mt_list; mtn != NULL; ++l, mtn = mtn->mt_next)
      fprintf(fp, "%s\t%s\n", mtn->mt_line, mtn->mt_line + mtn->mt_mtlen + 1);

   page_or_print(fp, l);
   Fclose(fp);
   }
   goto jleave;

jclear:
   while ((mtn = _mt_list) != NULL) {
      _mt_list = mtn->mt_next;
      free(mtn);
   }
   goto jleave;
}

FL void
mime_fromhdr(struct str const *in, struct str *out, enum tdflags flags)
{
   /* TODO mime_fromhdr(): is called with strings that contain newlines;
    * TODO this is the usual newline problem all around the codebase;
    * TODO i.e., if we strip it, then the display misses it ;>
    * TODO this is why it is so messy and why S-nail v14.2 plus additional
    * TODO patch for v14.5.2 (and maybe even v14.5.3 subminor) occurred, and
    * TODO why our display reflects what is contained in the message: the 1:1
    * TODO relationship of message content and display!
    * TODO instead a header line should be decoded to what it is (a single
    * TODO line that is) and it should be objective to the backend wether
    * TODO it'll be folded to fit onto the display or not, e.g., for search
    * TODO purposes etc.  then the only condition we have to honour in here
    * TODO is that whitespace in between multiple adjacent MIME encoded words
    * TODO á la RFC 2047 is discarded; i.e.: this function should deal with
    * TODO RFC 2047 and be renamed: mime_fromhdr() -> mime_rfc2047_decode() */
   struct str cin, cout;
   char *p, *op, *upper, *cs, *cbeg;
   ui32_t convert, lastenc, lastoutl;
#ifdef HAVE_ICONV
   char const *tcs;
   iconv_t fhicd = (iconv_t)-1;
#endif
   NYD_ENTER;

   out->l = 0;
   if (in->l == 0) {
      *(out->s = smalloc(1)) = '\0';
      goto jleave;
   }
   out->s = NULL;

#ifdef HAVE_ICONV
   tcs = charset_get_lc();
#endif
   p = in->s;
   upper = p + in->l;
   lastenc = lastoutl = 0;

   while (p < upper) {
      op = p;
      if (*p == '=' && *(p + 1) == '?') {
         p += 2;
         cbeg = p;
         while (p < upper && *p != '?')
            ++p;  /* strip charset */
         if (p >= upper)
            goto jnotmime;
         cs = salloc(PTR2SIZE(++p - cbeg));
         memcpy(cs, cbeg, PTR2SIZE(p - cbeg - 1));
         cs[p - cbeg - 1] = '\0';
#ifdef HAVE_ICONV
         if (fhicd != (iconv_t)-1)
            n_iconv_close(fhicd);
         fhicd = asccasecmp(cs, tcs) ? n_iconv_open(tcs, cs) : (iconv_t)-1;
#endif
         switch (*p) {
         case 'B': case 'b':
            convert = CONV_FROMB64;
            break;
         case 'Q': case 'q':
            convert = CONV_FROMQP;
            break;
         default: /* invalid, ignore */
            goto jnotmime;
         }
         if (*++p != '?')
            goto jnotmime;
         cin.s = ++p;
         cin.l = 1;
         for (;;) {
            if (PTRCMP(p + 1, >=, upper))
               goto jnotmime;
            if (*p++ == '?' && *p == '=')
               break;
            ++cin.l;
         }
         ++p;
         --cin.l;

         cout.s = NULL;
         cout.l = 0;
         if (convert == CONV_FROMB64) {
            /* XXX Take care for, and strip LF from
             * XXX [Invalid Base64 encoding ignored] */
            if (b64_decode(&cout, &cin, NULL) == STOP &&
                  cout.s[cout.l - 1] == '\n')
               --cout.l;
         } else
            qp_decode(&cout, &cin, NULL);

         out->l = lastenc;
#ifdef HAVE_ICONV
         if ((flags & TD_ICONV) && fhicd != (iconv_t)-1) {
            cin.s = NULL, cin.l = 0; /* XXX string pool ! */
            convert = n_iconv_str(fhicd, &cin, &cout, NULL, TRU1);
            out = n_str_add(out, &cin);
            if (convert) /* EINVAL at EOS */
               out = n_str_add_buf(out, "?", 1);
            free(cin.s);
         } else
#endif
            out = n_str_add(out, &cout);
         lastenc = lastoutl = out->l;
         free(cout.s);
      } else
jnotmime: {
         bool_t onlyws;

         p = op;
         onlyws = (lastenc > 0);
         for (;;) {
            if (++op == upper)
               break;
            if (op[0] == '=' && (PTRCMP(op + 1, ==, upper) || op[1] == '?'))
               break;
            if (onlyws && !blankchar(*op))
               onlyws = FAL0;
         }

         out = n_str_add_buf(out, p, PTR2SIZE(op - p));
         p = op;
         if (!onlyws || lastoutl != lastenc)
            lastenc = out->l;
         lastoutl = out->l;
      }
   }
   out->s[out->l] = '\0';

   if (flags & TD_ISPR) {
      makeprint(out, &cout);
      free(out->s);
      *out = cout;
   }
   if (flags & TD_DELCTRL)
      out->l = delctrl(out->s, out->l);
#ifdef HAVE_ICONV
   if (fhicd != (iconv_t)-1)
      n_iconv_close(fhicd);
#endif
jleave:
   NYD_LEAVE;
   return;
}

FL char *
mime_fromaddr(char const *name)
{
   char const *cp, *lastcp;
   char *res = NULL;
   size_t ressz = 1, rescur = 0;
   NYD_ENTER;

   if (name == NULL)
      goto jleave;
   if (*name == '\0') {
      res = savestr(name);
      goto jleave;
   }

   if ((cp = routeaddr(name)) != NULL && cp > name) {
      addconv(&res, &ressz, &rescur, name, PTR2SIZE(cp - name));
      lastcp = cp;
   } else
      cp = lastcp = name;

   for ( ; *cp; ++cp) {
      switch (*cp) {
      case '(':
         addstr(&res, &ressz, &rescur, lastcp, PTR2SIZE(cp - lastcp + 1));
         lastcp = ++cp;
         cp = skip_comment(cp);
         if (--cp > lastcp)
            addconv(&res, &ressz, &rescur, lastcp, PTR2SIZE(cp - lastcp));
         lastcp = cp;
         break;
      case '"':
         while (*cp) {
            if (*++cp == '"')
               break;
            if (*cp == '\\' && cp[1] != '\0')
               ++cp;
         }
         break;
      }
   }
   if (cp > lastcp)
      addstr(&res, &ressz, &rescur, lastcp, PTR2SIZE(cp - lastcp));
   /* TODO rescur==0: inserted to silence Coverity ...; check that */
   if (rescur == 0)
      res = UNCONST("");
   else
      res[rescur] = '\0';
   {  char *x = res;
      res = savestr(res);
      free(x);
   }
jleave:
   NYD_LEAVE;
   return res;
}

FL ssize_t
xmime_write(char const *ptr, size_t size, FILE *f, enum conversion convert,
   enum tdflags dflags, struct str *rest)
{
   ssize_t rv;
   struct quoteflt *qf;
   NYD_ENTER;

   quoteflt_reset(qf = quoteflt_dummy(), f);
   rv = mime_write(ptr, size, f, convert, dflags, qf, rest);
   assert(quoteflt_flush(qf) == 0);
   NYD_LEAVE;
   return rv;
}

FL ssize_t
mime_write(char const *ptr, size_t size, FILE *f,
   enum conversion convert, enum tdflags dflags,
   struct quoteflt *qf, struct str *rest)
{
   /* TODO note: after send/MIME layer rewrite we will have a string pool
    * TODO so that memory allocation count drops down massively; for now,
    * TODO v14.0 that is, we pay a lot & heavily depend on the allocator */
   struct str in, out;
   ssize_t sz;
   int state;
   NYD_ENTER;

   in.s = UNCONST(ptr);
   in.l = size;
   out.s = NULL;
   out.l = 0;

   dflags |= _TD_BUFCOPY;
   if ((sz = size) == 0) {
      if (rest != NULL && rest->l != 0)
         goto jconvert;
      goto jleave;
   }

#ifdef HAVE_ICONV
   if ((dflags & TD_ICONV) && iconvd != (iconv_t)-1 &&
         (convert == CONV_TOQP || convert == CONV_8BIT ||
         convert == CONV_TOB64 || convert == CONV_TOHDR)) {
      if (n_iconv_str(iconvd, &out, &in, NULL, FAL0) != 0) {
         /* XXX report conversion error? */;
         sz = -1;
         goto jleave;
      }
      in = out;
      out.s = NULL;
      dflags &= ~_TD_BUFCOPY;
   }
#endif

jconvert:
   switch (convert) {
   case CONV_FROMQP:
      state = qp_decode(&out, &in, rest);
      goto jqpb64_dec;
   case CONV_TOQP:
      qp_encode(&out, &in, QP_NONE);
      goto jqpb64_enc;
   case CONV_8BIT:
      sz = quoteflt_push(qf, in.s, in.l);
      break;
   case CONV_FROMB64:
      rest = NULL;
      /* FALLTHRU */
   case CONV_FROMB64_T:
      state = b64_decode(&out, &in, rest);
jqpb64_dec:
      if ((sz = out.l) != 0) {
         ui32_t opl = qf->qf_pfix_len;
         if (state != OKAY)
            qf->qf_pfix_len = 0;
         sz = _fwrite_td(&out, (dflags & ~_TD_BUFCOPY), rest, qf);
         qf->qf_pfix_len = opl;
      }
      if (state != OKAY)
         sz = -1;
      break;
   case CONV_TOB64:
      b64_encode(&out, &in, B64_LF | B64_MULTILINE);
jqpb64_enc:
      sz = fwrite(out.s, sizeof *out.s, out.l, f);
      if (sz != (ssize_t)out.l)
         sz = -1;
      break;
   case CONV_FROMHDR:
      mime_fromhdr(&in, &out, TD_ISPR | TD_ICONV | (dflags & TD_DELCTRL));
      sz = quoteflt_push(qf, out.s, out.l);
      break;
   case CONV_TOHDR:
      sz = mime_write_tohdr(&in, f);
      break;
   case CONV_TOHDR_A:
      sz = mime_write_tohdr_a(&in, f);
      break;
   default:
      sz = _fwrite_td(&in, dflags, NULL, qf);
      break;
   }
jleave:
   if (out.s != NULL)
      free(out.s);
   if (in.s != ptr)
      free(in.s);
   NYD_LEAVE;
   return sz;
}

/* vim:set fenc=utf-8:s-it-mode */