mime_param.c

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ MIME parameter handling.
   3  *
   4  * Copyright (c) 2016 - 2017 Steffen (Daode) Nurpmeso <steffen@sdaoden.eu>.
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18 #undef n_FILE
  19 #define n_FILE mime_param
  20
  21 #ifndef HAVE_AMALGAMATION
  22 # include "nail.h"
  23 #endif
  24
  25 struct rfc2231_joiner {
  26    struct rfc2231_joiner *rj_next;
  27    ui32_t      rj_no;            /* Continuation number */
  28    ui32_t      rj_len;           /* of useful data in .rj_dat */
  29    ui32_t      rj_val_off;       /* Start of value data therein */
  30    ui32_t      rj_cs_len;        /* Length of charset part */
  31    bool_t      rj_is_enc;        /* Is percent encoded */
  32    ui8_t       __pad[7];
  33    char const  *rj_dat;
  34 };
  35
  36 struct mime_param_builder {
  37    struct mime_param_builder *mpb_next;
  38    struct str  *mpb_result;
  39    ui32_t      mpb_level;        /* of recursion (<-> continuation number) */
  40    ui32_t      mpb_name_len;     /* of the parameter .mpb_name */
  41    ui32_t      mpb_value_len;    /* of remaining value */
  42    ui32_t      mpb_charset_len;  /* of .mpb_charset (only in outermost level) */
  43    ui32_t      mpb_buf_len;      /* Usable result of this level in .mpb_buf */
  44    bool_t      mpb_is_enc;       /* Level requires encoding */
  45    ui8_t       __dummy[1];
  46    bool_t      mpb_is_utf8;      /* Encoding is UTF-8 */
  47    si8_t       mpb_rv;
  48    char const  *mpb_name;
  49    char const  *mpb_value;       /* Remains of, once the level was entered */
  50    char const  *mpb_charset;     /* *ttycharset* */
  51    char        *mpb_buf;         /* Pointer to on-stack buffer */
  52 };
  53
  54 /* All ASCII characters which cause RFC 2231 to be applied XXX check -1 slots*/
  55 static bool_t const        _rfc2231_etab[] = {
  56     1, 1, 1, 1,  1, 1, 1, 1,  1, 1,-1,-1,  1,-1, 1, 1,   /* NUL..SI */
  57     1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,   /* DLE..US */
  58     1, 0, 1, 0,  0, 1, 0, 1,  1, 1, 1, 0,  1, 0, 0, 1,   /* CAN.. / */
  59     0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 1, 1,  1, 1, 1, 1,   /*   0.. ? */
  60
  61     1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,   /*   @.. O */
  62     0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 1,  1, 1, 0, 0,   /*   P.. _ */
  63     0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,   /*   `.. o */
  64     0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 1,   /*   p..DEL */
  65 };
  66
  67 /* In a headerbody, at a "param=XY" that we're not interested in, skip over the
  68  * entire construct, return pointer to the first byte thereafter or to NUL */
  69 static char const * _mime_param_skip(char const *hbp);
  70
  71 /* Trim value, which points to after the "name[RFC 2231 stuff]=".
  72  * On successful return (1,-1; -1 is returned if the value was quoted via
  73  * double quotation marks) a set end_or_null points to after the value and any
  74  * possible separator and result->s is the salloc()d normalized value */
  75 static si8_t      _mime_param_value_trim(struct str *result, char const *start,
  76                      char const **end_or_null);
  77
  78 /* mime_param_get() found the desired parameter but it seems to use RFC 2231
  79  * extended syntax: perform full RFC 2231 parsing starting at this point.
  80  * Note that _join() returns is-error */
  81 static char *     _rfc2231_param_parse(char const *param, size_t plen,
  82                      char const *hbp);
  83 static bool_t     __rfc2231_join(struct rfc2231_joiner *head, char **result,
  84                      char const **emsg);
  85
  86 /* Recursive parameter builder.  Note we have a magic limit of 999 levels.
  87  * Prepares a portion of output in self->mpb_buf;
  88  * once >mpb_value is worked completely the deepmost level joins the result
  89  * into >mpb_result and unrolls the stack. */
  90 static void       _mime_param_create(struct mime_param_builder *self);
  91 static void       __mime_param_join(struct mime_param_builder *head);
  92
  93 static char const *
  94 _mime_param_skip(char const *hbp)
  95 {
  96    char co, cn;
  97    NYD2_ENTER;
  98
  99    /* Skip over parameter name - note we may have skipped over an entire
 100     * parameter name and thus point to a "="; i haven't yet truly checked
 101     * against MIME RFCs, just test for ";" in the meanwhile XXX */
 102    while ((cn = *hbp) != '\0' && cn != '=' && cn != ';')
 103       ++hbp;
 104    if (cn == '\0')
 105       goto jleave;
 106    ++hbp;
 107    if (cn == ';')
 108       goto jleave;
 109
 110    while (whitechar((cn = *hbp))) /* XXX */
 111       ++hbp;
 112    if (cn == '\0')
 113       goto jleave;
 114
 115    if (cn == '"') {
 116       co = '\0';
 117       while ((cn = *++hbp) != '\0' && (cn != '"' || co == '\\'))
 118          co = (co == '\\') ? '\0' : cn;
 119       if (cn != '\0' && (cn = *++hbp) == ';')
 120          ++hbp;
 121    } else {
 122       for (;; cn = *++hbp)
 123          if (cn == '\0' || cn == ';' || whitechar(cn))
 124             break;
 125       if (cn != '\0')
 126          ++hbp;
 127    }
 128 jleave:
 129    NYD2_LEAVE;
 130    return hbp;
 131 }
 132
 133 static si8_t
 134 _mime_param_value_trim(struct str *result, char const *start,
 135    char const **end_or_null)
 136 {
 137    char const *e;
 138    char co, cn;
 139    size_t i;
 140    si8_t rv;
 141    NYD2_ENTER;
 142
 143    while (whitechar(*start)) /* XXX? */
 144       ++start;
 145
 146    if (*start == '"') {
 147       for (co = '\0', e = ++start;; ++e)
 148          if ((cn = *e) == '\0')
 149             goto jerr;
 150          else if (cn == '"' && co != '\\')
 151             break;
 152          else if (cn == '\\' && co == '\\')
 153             co = '\0';
 154          else
 155             co = cn;
 156       i = PTR2SIZE(e++ - start);
 157       rv = -TRU1;
 158    } else {
 159       for (e = start; (cn = *e) != '\0' && !whitechar(cn) && cn != ';'; ++e)
 160          ;
 161       i = PTR2SIZE(e - start);
 162       rv = TRU1;
 163    }
 164
 165    result->s = salloc(i +1);
 166    if (rv > 0) {
 167       memcpy(result->s, start, result->l = i);
 168       result->s[i] = '\0';
 169    } else {
 170       size_t j;
 171       char *cp;
 172
 173       for (j = 0, cp = result->s, co = '\0'; i-- > 0; co = cn) {
 174          cn = *start++;
 175          if (cn != '\\' || co == '\\') {
 176             cp[j++] = cn;
 177             if (cn == '\\')
 178                cn = '\0';
 179          }
 180       }
 181       cp[j] = '\0';
 182
 183       result->s = cp;
 184       result->l = j;
 185    }
 186
 187    if (end_or_null != NULL) {
 188       while (*e != '\0' && *e == ';')
 189          ++e;
 190       *end_or_null = e;
 191    }
 192 jleave:
 193    NYD2_LEAVE;
 194    return rv;
 195 jerr:
 196    rv = FAL0;
 197    goto jleave;
 198 }
 199
 200 static char *
 201 _rfc2231_param_parse(char const *param, size_t plen, char const *hbp)
 202 {
 203    /* TODO Do it for real and unite with mime_param_get() */
 204    struct str xval;
 205    char nobuf[32], *eptr, *rv = NULL, c;
 206    char const *hbp_base, *cp, *emsg = NULL;
 207    struct rfc2231_joiner *head = NULL, *np;
 208    bool_t errors = FAL0;
 209    size_t i;
 210    NYD2_ENTER;
 211
 212    /* We were called by mime_param_get() after a param name match that
 213     * involved "*", so jump to the matching code */
 214    hbp_base = hbp;
 215    goto jumpin;
 216
 217    for (; *hbp != '\0'; hbp_base = hbp) {
 218       while (whitechar(*hbp))
 219          ++hbp;
 220
 221       if (!ascncasecmp(hbp, param, plen)) {
 222          hbp += plen;
 223          while (whitechar(*hbp))
 224             ++hbp;
 225          if (*hbp++ != '*')
 226                goto jerr;
 227
 228          /* RFC 2231 extensions: "NAME[*DIGITS][*]=", where "*DIGITS" indicates
 229           * parameter continuation and the lone asterisk "*" percent encoded
 230           * values -- if encoding is used the "*0" or lone parameter value
 231           * MUST be encoded and start with a "CHARSET'LANGUAGE'" construct,
 232           * where both of CHARSET and LANGUAGE are optional (we do effectively
 233           * generate error if CHARSET is missing though).
 234           * Continuations may not use that "C'L'" construct, but be tolerant
 235           * and ignore those.  Also encoded and non-encoded continuations may
 236           * occur, i.e., perform percent en-/decoding only as necessary.
 237           * Continuations may occur in any order */
 238          /* xxx RFC 2231 parsing ignores language tags */
 239 jumpin:
 240          for (cp = hbp; digitchar(*cp); ++cp)
 241             ;
 242          i = PTR2SIZE(cp - hbp);
 243          if (i != 0) {
 244             if (i >= sizeof(nobuf)) {
 245                emsg = N_("too many digits to form a valid number");
 246                goto jerr;
 247             } else if ((c = *cp) != '=' && c != '*') {
 248                emsg = N_("expected = or * after leading digits");
 249                goto jerr;
 250             }
 251             memcpy(nobuf, hbp, i);
 252             nobuf[i] = '\0';
 253             i = (size_t)strtol(nobuf, n_UNCONST(&eptr), 10);
 254             if (i >= 999 || *eptr != '\0') {
 255                emsg = N_("invalid continuation sequence number");
 256                goto jerr;
 257             }
 258             hbp = ++cp;
 259
 260             /* Value encoded? */
 261             if (c == '*') {
 262                if (*hbp++ != '=')
 263                   goto jeeqaaster;
 264             } else if (c != '=') {
 265 jeeqaaster:
 266                emsg = N_("expected = after asterisk *");
 267                goto jerr;
 268             }
 269          } else {
 270             /* In continuation mode that is an error, however */
 271             if (head != NULL) {
 272                emsg = N_("missing continuation sequence number");
 273                goto jerr;
 274             }
 275             /* Parameter value is encoded, may define encoding */
 276             c = '*';
 277             if (*cp != '=')
 278                goto jeeqaaster;
 279             hbp = ++cp;
 280             i = 0;
 281          }
 282
 283          /* Create new node and insert it sorted; should be faster than
 284           * creating an unsorted list and sorting it after parsing */
 285          np = smalloc(sizeof *np);
 286          np->rj_next = NULL;
 287          np->rj_no = (ui32_t)i;
 288          np->rj_is_enc = (c == '*');
 289          np->rj_val_off = np->rj_cs_len = 0;
 290
 291          if (head == NULL)
 292             head = np;
 293          else if (i < head->rj_no) {
 294             np->rj_next = head;
 295             head = np;
 296          } else {
 297             struct rfc2231_joiner *l = NULL, *x = head;
 298
 299             while (x != NULL && i > x->rj_no)
 300                l = x, x = x->rj_next;
 301             if (x != NULL)
 302                np->rj_next = x;
 303             assert(l != NULL);
 304             l->rj_next = np;
 305          }
 306
 307          switch (_mime_param_value_trim(&xval, hbp, &cp)) {
 308          default:
 309             emsg = (c == '*') ? N_("invalid value encoding")/* XXX fake */
 310                   : N_("faulty value - missing closing quotation mark \"?");
 311             goto jerr;
 312          case -1:
 313             /* XXX if (np->is_enc && memchr(np->dat, '\'', i) != NULL) {
 314              * XXX    emsg = N_("character set info not allowed here");
 315              * XXX    goto jerr;
 316              * XXX } */np->rj_is_enc = FAL0; /* Silently ignore */
 317             /* FALLTHRU */
 318          case 1:
 319             if (xval.l >= UI32_MAX) {
 320                emsg = N_("parameter value too long");
 321                goto jerr;
 322             }
 323             np->rj_len = (ui32_t)xval.l;
 324             np->rj_dat = xval.s;
 325             break;
 326          }
 327
 328          /* Watch out for character set and language info */
 329          if (np->rj_is_enc && (eptr = memchr(xval.s, '\'', xval.l)) != NULL) {
 330             np->rj_cs_len = PTR2SIZE(eptr - xval.s);
 331             if ((eptr = memchr(eptr + 1, '\'', xval.l - np->rj_cs_len - 1))
 332                   == NULL) {
 333                emsg = N_("faulty RFC 2231 parameter extension");
 334                goto jerr;
 335             }
 336             np->rj_val_off = PTR2SIZE(++eptr - xval.s);
 337          }
 338
 339          hbp = cp;
 340       } else
 341          hbp = _mime_param_skip(hbp);
 342    }
 343    assert(head != NULL); /* (always true due to jumpin:, but..) */
 344
 345    errors |= __rfc2231_join(head, &rv, &emsg);
 346    if (errors && (options & OPT_D_V_VV)) {
 347       /* TODO should set global flags so that at the end of an operation
 348        * TODO (for a message) a summary can be printed: faulty MIME, xy */
 349       if (emsg == NULL)
 350          emsg = N_("multiple causes");
 351       n_err(_("Message had MIME errors: %s\n"), V_(emsg));
 352    }
 353 jleave:
 354    NYD2_LEAVE;
 355    return rv;
 356
 357 jerr:
 358    while ((np = head) != NULL) {
 359       head = np->rj_next;
 360       free(np);
 361    }
 362    if (options & OPT_D_V) {
 363       if (emsg == NULL)
 364          emsg = N_("expected asterisk *");
 365       n_err(_("Faulty RFC 2231 MIME parameter value: %s: %s\n"
 366          "Near: %s\n"), param, V_(emsg), hbp_base);
 367    }
 368    rv = NULL;
 369    goto jleave;
 370 }
 371
 372 static bool_t
 373 __rfc2231_join(struct rfc2231_joiner *head, char **result, char const **emsg)
 374 {
 375    struct str sin, sou;
 376    struct rfc2231_joiner *np;
 377    char const *cp;
 378    size_t i;
 379    enum {
 380       _NONE       = 0,
 381       _HAVE_ENC   = 1<<0,
 382       _HAVE_ICONV = 1<<1,
 383       _SEEN_ANY   = 1<<2,
 384       _ERRORS     = 1<<3
 385    } f = _NONE;
 386    ui32_t no;
 387 #ifdef HAVE_ICONV
 388    iconv_t fhicd;
 389 #endif
 390    NYD2_ENTER;
 391
 392 #ifdef HAVE_ICONV
 393    n_UNINIT(fhicd, (iconv_t)-1);
 394
 395    if (head->rj_is_enc) {
 396       char const *tcs;
 397
 398       f |= _HAVE_ENC;
 399       if (head->rj_cs_len == 0) {
 400          /* It is an error if the character set is not set, the language alone
 401           * cannot convert characters, let aside that we don't use it at all */
 402          *emsg = N_("MIME RFC 2231 invalidity: missing character set\n");
 403          f |= _ERRORS;
 404       } else if (ascncasecmp(tcs = ok_vlook(ttycharset),
 405             head->rj_dat, head->rj_cs_len)) {
 406          char *cs = ac_alloc(head->rj_cs_len +1);
 407
 408          memcpy(cs, head->rj_dat, head->rj_cs_len);
 409          cs[head->rj_cs_len] = '\0';
 410          if ((fhicd = n_iconv_open(tcs, cs)) != (iconv_t)-1)
 411             f |= _HAVE_ICONV;
 412          else {
 413             *emsg = N_("necessary character set conversion missing");
 414             f |= _ERRORS;
 415          }
 416          ac_free(cs);
 417       }
 418    }
 419 #endif
 420
 421    if (head->rj_no != 0) {
 422       if (!(f & _ERRORS))
 423          *emsg = N_("First RFC 2231 parameter value chunk number is not 0");
 424       f |= _ERRORS;
 425    }
 426
 427    for (sou.s = NULL, sou.l = 0, no = 0; (np = head) != NULL; free(np)) {
 428       head = np->rj_next;
 429
 430       if (np->rj_no != no++) {
 431          if (!(f & _ERRORS))
 432             *emsg = N_("RFC 2231 parameter value chunks are not contiguous");
 433          f |= _ERRORS;
 434       }
 435
 436       /* RFC 2231 allows such info only in the first continuation, and
 437        * furthermore MUSTs the first to be encoded, then */
 438       if (/*np->rj_is_enc &&*/ np->rj_val_off > 0 &&
 439             (f & (_HAVE_ENC | _SEEN_ANY)) != _HAVE_ENC) {
 440          if (!(f & _ERRORS))
 441             *emsg = N_("invalid redundant RFC 2231 charset/language ignored");
 442          f |= _ERRORS;
 443       }
 444       f |= _SEEN_ANY;
 445
 446       i = np->rj_len - np->rj_val_off;
 447       if (!np->rj_is_enc)
 448          n_str_add_buf(&sou, np->rj_dat + np->rj_val_off, i);
 449       else {
 450          /* Perform percent decoding */
 451          sin.s = smalloc(i +1);
 452          sin.l = 0;
 453
 454          for (cp = np->rj_dat + np->rj_val_off; i > 0;) {
 455             char c;
 456
 457             if ((c = *cp++) == '%') {
 458                si32_t cc;
 459
 460                if (i < 3 || (cc = n_c_from_hex_base16(cp)) < 0) {
 461                   if (!(f & _ERRORS))
 462                      *emsg = N_("invalid RFC 2231 percent encoded sequence");
 463                   f |= _ERRORS;
 464                   goto jhex_putc;
 465                }
 466                sin.s[sin.l++] = (char)cc;
 467                cp += 2;
 468                i -= 3;
 469             } else {
 470 jhex_putc:
 471                sin.s[sin.l++] = c;
 472                --i;
 473             }
 474          }
 475          sin.s[sin.l] = '\0';
 476
 477          n_str_add_buf(&sou, sin.s, sin.l);
 478          free(sin.s);
 479       }
 480    }
 481
 482    /* And add character set conversion on top as necessary.
 483     * RFC 2231 is pragmatic: encode only mentions percent encoding and the
 484     * character set for the entire string ("[no] facility for using more
 485     * than one character set or language"), therefore "continuations may
 486     * contain a mixture of encoded and unencoded segments" applies to
 487     * a contiguous string of a single character set that has been torn in
 488     * pieces due to space restrictions, and it happened that some pieces
 489     * didn't need to be percent encoded.
 490     *
 491     * _In particular_ it therefore doesn't repeat the RFC 2047 paradigm
 492     * that encoded-words-are-atomic, meaning that a single character-set
 493     * conversion run over the final, joined, partially percent-decoded value
 494     * should be sufficient */
 495 #ifdef HAVE_ICONV
 496    if (f & _HAVE_ICONV) {
 497       sin.s = NULL;
 498       sin.l = 0;
 499       if (n_iconv_str(fhicd, n_ICONV_UNIDEFAULT, &sin, &sou, NULL) != 0) {
 500          if (!(f & _ERRORS)) /* XXX won't be reported with _UNIDFEFAULT */
 501             *emsg = N_("character set conversion failed on value");
 502          f |= _ERRORS;
 503       }
 504       free(sou.s);
 505       sou = sin;
 506
 507       n_iconv_close(fhicd);
 508    }
 509 #endif
 510
 511    memcpy(*result = salloc(sou.l +1), sou.s, sou.l +1);
 512    free(sou.s);
 513    NYD2_LEAVE;
 514    return ((f & _ERRORS) != 0);
 515 }
 516
 517 static void
 518 _mime_param_create(struct mime_param_builder *self)
 519 {
 520    struct mime_param_builder next;
 521    /* Don't use MIME_LINELEN_(MAX|LIMIT) stack buffer sizes: normally we won't
 522     * exceed plain MIME_LINELEN, so that this would be a factor 10 wastage.
 523     * On the other hand we may excess _LINELEN to avoid breaking up possible
 524     * multibyte sequences until sizeof(buf) is reached, but since we (a) don't
 525     * support stateful encodings and (b) will try to synchronize on UTF-8 this
 526     * problem is scarce, possibly even artificial */
 527    char buf[n_MIN(MIME_LINELEN_MAX >> 1, MIME_LINELEN * 2)],
 528       *bp, *bp_max, *bp_xmax, *bp_lanoenc;
 529    char const *vb, *vb_lanoenc;
 530    size_t vl;
 531    enum {
 532       _NONE    = 0,
 533       _ISENC   = 1<<0,
 534       _HADRAW  = 1<<1,
 535       _RAW     = 1<<2
 536    } f = _NONE;
 537    NYD2_ENTER;
 538    n_LCTA(sizeof(buf) >= MIME_LINELEN * 2, "Buffer to small for operation");
 539
 540 jneed_enc:
 541    self->mpb_buf = bp = bp_lanoenc = buf;
 542    self->mpb_buf_len = 0;
 543    self->mpb_is_enc = ((f & _ISENC) != 0);
 544    vb_lanoenc = vb = self->mpb_value;
 545    vl = self->mpb_value_len;
 546
 547    /* Configure bp_max to fit in SHOULD, bp_xmax to extent */
 548    bp_max = (buf + MIME_LINELEN) -
 549          (1 + self->mpb_name_len + sizeof("*999*='';") -1 + 2);
 550    bp_xmax = (buf + sizeof(buf)) -
 551          (1 + self->mpb_name_len + sizeof("*999*='';") -1 + 2);
 552    if ((f & _ISENC) && self->mpb_level == 0) {
 553       bp_max -= self->mpb_charset_len;
 554       bp_xmax -= self->mpb_charset_len;
 555    }
 556    if (PTRCMP(bp_max, <=, buf + sizeof("Hunky Dory"))) {
 557       DBG( n_alert("_mime_param_create(): Hunky Dory!"); )
 558       bp_max = buf + (MIME_LINELEN >> 1); /* And then it is SHOULD, anyway */
 559    }
 560    assert(PTRCMP(bp_max + (4 * 3), <=, bp_xmax)); /* UTF-8 extra pad, below */
 561
 562    f &= _ISENC;
 563    while (vl > 0) {
 564       union {char c; ui8_t uc;} u; u.c = *vb;
 565
 566       f |= _RAW;
 567       if (!(f & _ISENC)) {
 568          if (u.uc > 0x7F || cntrlchar(u.c)) { /* XXX reject cntrlchar? */
 569             /* We need to percent encode this character, possibly changing
 570              * overall strategy, but anyway the one of this level, possibly
 571              * rendering invalid any output byte we yet have produced here.
 572              * Instead of throwing away that work just recurse if some fancy
 573              * magic condition is true */
 574              /* *However*, many tested MUAs fail to deal with parameters that
 575               * are splitted across "too many" fields, including ones that
 576               * misread RFC 2231 to allow only one digit, i.e., a maximum of
 577               * ten.  This is plain wrong, but that won't help their users */
 578             if (PTR2SIZE(bp - buf) > /*10 (strawberry) COMPAT*/MIME_LINELEN>>1)
 579                goto jrecurse;
 580             f |= _ISENC;
 581             goto jneed_enc;
 582          }
 583
 584          if (u.uc == '"' || u.uc == '\\') {
 585             f ^= _RAW;
 586             bp[0] = '\\';
 587             bp[1] = u.c;
 588             bp += 2;
 589          }
 590       } else if (u.uc > 0x7F || _rfc2231_etab[u.uc]) {
 591          f ^= _RAW;
 592          bp[0] = '%';
 593          n_c_to_hex_base16(bp + 1, u.c);
 594          bp += 3;
 595       }
 596
 597       ++vb;
 598       --vl;
 599       if (f & _RAW) {
 600          f |= _HADRAW;
 601          vb_lanoenc = vb;
 602          *bp++ = u.c;
 603          bp_lanoenc = bp;
 604       }
 605
 606       /* If all available space has been consumed we must split.
 607        * Due to compatibility reasons we must take care not to break up
 608        * multibyte sequences -- even though RFC 2231 rather implies that the
 609        * splitted value should be joined (after percent encoded fields have
 610        * been percent decoded) and the resulting string be treated in the
 611        * specified character set / language, MUAs have been seen which apply
 612        * the RFC 2047 encoded-words-are-atomic even to RFC 2231 values, even
 613        * if stateful encodings cannot truly be supported like that?!..
 614        *
 615        * So split at 7-bit character if we have seen any and the wastage isn't
 616        * too large; recall that we need to keep the overall number of P=V
 617        * values as low as possible due to compatibility reasons.
 618        * If we haven't seen any plain bytes be laxe and realize that bp_max
 619        * reflects SHOULD lines, and try to extend this as long as possible.
 620        * However, with UTF-8, try to backward synchronize on sequence start */
 621       if (bp <= bp_max)
 622          continue;
 623
 624       if ((f & _HADRAW) && (PTRCMP(bp - bp_lanoenc, <=, bp_lanoenc - buf) ||
 625             (!self->mpb_is_utf8 &&
 626              PTR2SIZE(bp_lanoenc - buf) >= (MIME_LINELEN >> 2)))) {
 627          bp = bp_lanoenc;
 628          vl += PTR2SIZE(vb - vb_lanoenc);
 629          vb = vb_lanoenc;
 630          goto jrecurse;
 631       }
 632
 633       if (self->mpb_is_utf8 && ((ui8_t)(vb[-1]) & 0xC0) != 0x80) {
 634          bp -= 3;
 635          --vb;
 636          ++vl;
 637          goto jrecurse;
 638       }
 639
 640       if (bp <= bp_xmax)
 641          continue;
 642       /* (Shit.) */
 643       goto jrecurse;
 644    }
 645
 646    /* That level made the great and completed encoding.  Build result */
 647    self->mpb_is_enc = ((f & _ISENC) != 0);
 648    self->mpb_buf_len = PTR2SIZE(bp - buf);
 649    __mime_param_join(self);
 650 jleave:
 651    NYD2_LEAVE;
 652    return;
 653
 654    /* Need to recurse, take care not to excess magical limit of 999 levels */
 655 jrecurse:
 656    if (self->mpb_level == 999) {
 657       if (options & OPT_D_V_VV)
 658          n_err(_("Message RFC 2231 parameters nested too deeply!\n"));
 659       goto jleave;
 660    }
 661
 662    self->mpb_is_enc = ((f & _ISENC) != 0);
 663    self->mpb_buf_len = PTR2SIZE(bp - buf);
 664
 665    memset(&next, 0, sizeof next);
 666    next.mpb_next = self;
 667    next.mpb_level = self->mpb_level + 1;
 668    next.mpb_name_len = self->mpb_name_len;
 669    next.mpb_value_len = vl;
 670    next.mpb_is_utf8 = self->mpb_is_utf8;
 671    next.mpb_name = self->mpb_name;
 672    next.mpb_value = vb;
 673    _mime_param_create(&next);
 674    goto jleave;
 675 }
 676
 677 static void
 678 __mime_param_join(struct mime_param_builder *head)
 679 {
 680    char nobuf[16];
 681    struct mime_param_builder *np;
 682    size_t i, ll;  DBG( size_t len_max; )
 683    struct str *result;
 684    char *cp;
 685    enum {
 686       _NONE    = 0,
 687       _ISENC   = 1<<0,
 688       _ISQUOTE = 1<<1,
 689       _ISCONT  = 1<<2
 690    } f = _NONE;
 691    NYD2_ENTER;
 692
 693    /* Traverse the stack upwards to find out result length (worst case).
 694     * Reverse the list while doing so */
 695    for (i = 0, np = head, head = NULL; np != NULL;) {
 696       struct mime_param_builder *tmp;
 697
 698       i += np->mpb_buf_len + np->mpb_name_len + sizeof(" *999*=\"\";\n") -1;
 699       if (np->mpb_is_enc)
 700          f |= _ISENC;
 701
 702       tmp = np->mpb_next;
 703       np->mpb_next = head;
 704       head = np;
 705       np = tmp;
 706    }
 707    if (f & _ISENC)
 708       i += head->mpb_charset_len; /* sizeof("''") -1 covered by \"\" above */
 709    DBG( len_max = i; )
 710    head->mpb_rv = TRU1;
 711
 712    result = head->mpb_result;
 713    if (head->mpb_next != NULL)
 714       f |= _ISCONT;
 715    cp = result->s = salloc(i +1);
 716
 717    for (ll = 0, np = head;;) {
 718       /* Name part */
 719       memcpy(cp, np->mpb_name, i = np->mpb_name_len);
 720       cp += i;
 721       ll += i;
 722
 723       if (f & _ISCONT) {
 724          char *cpo = cp, *nop = nobuf + sizeof(nobuf);
 725          ui32_t noi = np->mpb_level;
 726
 727          *--nop = '\0';
 728          do
 729             *--nop = "0123456789"[noi % 10];
 730          while ((noi /= 10) != 0);
 731
 732          *cp++ = '*';
 733          while (*nop != '\0')
 734             *cp++ = *nop++;
 735
 736          ll += PTR2SIZE(cp - cpo);
 737       }
 738
 739       if ((f & _ISENC) || np->mpb_is_enc) {
 740          *cp++ = '*';
 741          ++ll;
 742       }
 743       *cp++ = '=';
 744       ++ll;
 745
 746       /* Value part */
 747       if (f & _ISENC) {
 748          f &= ~_ISENC;
 749          memcpy(cp, np->mpb_charset, i = np->mpb_charset_len);
 750          cp += i;
 751          cp[0] = '\'';
 752          cp[1] = '\'';
 753          cp += 2;
 754          ll += i + 2;
 755       } else if (!np->mpb_is_enc) {
 756          f |= _ISQUOTE;
 757          *cp++ = '"';
 758          ++ll;
 759       }
 760
 761       memcpy(cp, np->mpb_buf, i = np->mpb_buf_len);
 762       cp += i;
 763       ll += i;
 764
 765       if (f & _ISQUOTE) {
 766          f ^= _ISQUOTE;
 767          *cp++ = '"';
 768          ++ll;
 769       }
 770
 771       if ((np = np->mpb_next) == NULL)
 772          break;
 773       *cp++ = ';';
 774       ++ll;
 775
 776       i = ll;
 777       i += np->mpb_name_len + np->mpb_buf_len + sizeof(" *999*=\"\";\n") -1;
 778       if (i >= MIME_LINELEN) {
 779          head->mpb_rv = -TRU1;
 780          *cp++ = '\n';
 781          ll = 0;
 782       }
 783
 784       *cp++ = ' ';
 785       ++ll;
 786    }
 787    *cp = '\0';
 788    result->l = PTR2SIZE(cp - result->s);
 789    assert(result->l < len_max);
 790    NYD2_LEAVE;
 791 }
 792
 793 FL char *
 794 mime_param_get(char const *param, char const *headerbody) /* TODO rewr. */
 795 {
 796    struct str xval;
 797    char *rv = NULL;
 798    size_t plen;
 799    char const *p;
 800    NYD_ENTER;
 801
 802    plen = strlen(param);
 803    p = headerbody;
 804
 805    /* At the beginning of headerbody there is no parameter=value pair xxx */
 806    if (!whitechar(*p))
 807       goto jskip1st;
 808
 809    for (;;) {
 810       while (whitechar(*p))
 811          ++p;
 812
 813       if (!ascncasecmp(p, param, plen)) {
 814          p += plen;
 815          while (whitechar(*p)) /* XXX? */
 816             ++p;
 817          switch (*p++) {
 818          case '*':
 819             rv = _rfc2231_param_parse(param, plen, p);
 820             goto jleave;
 821          case '=':
 822             if (!_mime_param_value_trim(&xval, p, NULL)) {
 823                /* XXX LOG? */
 824                goto jleave;
 825             }
 826             rv = xval.s;
 827
 828             /* We do have a result, but some (elder) software (S-nail <v14.8)
 829              * will use RFC 2047 encoded words in  parameter values, too */
 830             /* TODO Automatically check whether the value seems to be RFC 2047
 831              * TODO encwd. -- instead use *rfc2047_parameters* like mutt(1)? */
 832             if ((p = strstr(rv, "=?")) != NULL && strstr(p, "?=") != NULL) {
 833                struct str ti, to;
 834
 835                ti.l = strlen(ti.s = rv);
 836                mime_fromhdr(&ti, &to, TD_ISPR | TD_ICONV | TD_DELCTRL);
 837                rv = savestrbuf(to.s, to.l);
 838                free(to.s);
 839             }
 840             goto jleave;
 841          default:
 842             /* Not our desired parameter, skip and continue */
 843             break;
 844          }
 845       }
 846
 847 jskip1st:
 848       if (*(p = _mime_param_skip(p)) == '\0')
 849          goto jleave;
 850    }
 851
 852 jleave:
 853    NYD_LEAVE;
 854    return rv;
 855 }
 856
 857 FL si8_t
 858 mime_param_create(struct str *result, char const *name, char const *value)
 859 {
 860    /* TODO All this needs rework when we have (1) a real string and even more
 861     * TODO (2) use objects instead of stupid string concat; it's temporary
 862     * TODO I.e., this function should return a HeaderBodyParam */
 863    struct mime_param_builder top;
 864    size_t i;
 865    NYD_ENTER;
 866
 867    memset(result, 0, sizeof *result);
 868
 869    memset(&top, 0, sizeof top);
 870    top.mpb_result = result;
 871    if ((i = strlen(top.mpb_name = name)) > UI32_MAX)
 872       goto jleave;
 873    top.mpb_name_len = (ui32_t)i;
 874    if ((i = strlen(top.mpb_value = value)) > UI32_MAX)
 875       goto jleave;
 876    top.mpb_value_len = (ui32_t)i;
 877    if ((i = strlen(name = ok_vlook(ttycharset))) > UI32_MAX)
 878       goto jleave;
 879    top.mpb_charset = salloc((top.mpb_charset_len = (ui32_t)i) +1);
 880    for (i = 0; *name != '\0'; ++i, ++name)
 881       ((char*)n_UNCONST(top.mpb_charset))[i] = lowerconv(*name);
 882    ((char*)n_UNCONST(top.mpb_charset))[i] = '\0';
 883    if(top.mpb_charset_len >= 4 && !ascncasecmp(top.mpb_charset, "utf", 3) &&
 884          ((top.mpb_charset[3] == '-' && top.mpb_charset[4] == '8' &&
 885           top.mpb_charset_len == 5) || (top.mpb_charset[3] == '8' &&
 886           top.mpb_charset_len == 4)))
 887       top.mpb_is_utf8 = TRU1;
 888    else
 889       top.mpb_is_utf8 = FAL0;
 890
 891    _mime_param_create(&top);
 892 jleave:
 893    NYD_LEAVE;
 894    return top.mpb_rv;
 895 }
 896
 897 FL char *
 898 mime_param_boundary_get(char const *headerbody, size_t *len)
 899 {
 900    char *q = NULL, *p;
 901    NYD_ENTER;
 902
 903    if ((p = mime_param_get("boundary", headerbody)) != NULL) {
 904       size_t sz = strlen(p);
 905
 906       if (len != NULL)
 907          *len = sz + 2;
 908       q = salloc(sz + 2 +1);
 909       q[0] = q[1] = '-';
 910       memcpy(q + 2, p, sz);
 911       *(q + sz + 2) = '\0';
 912    }
 913    NYD_LEAVE;
 914    return q;
 915 }
 916
 917 FL char *
 918 mime_param_boundary_create(void)
 919 {
 920    char *bp;
 921    NYD_ENTER;
 922
 923    bp = salloc(36 + 6 +1);
 924    bp[0] = bp[2] = bp[39] = bp[41] = '=';
 925    bp[1] = bp[40] = '-';
 926    memcpy(bp + 3, getrandstring(36), 36);
 927    bp[42] = '\0';
 928    NYD_LEAVE;
 929    return bp;
 930 }
 931
 932 /* s-it-mode */