mime_param.c

   1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
   2  *@ MIME parameter handling.
   3  *
   4  * Copyright (c) 2015 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
   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;     /* charset_get_lc() */
  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, 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             l->rj_next = np;
 304          }
 305
 306          switch (_mime_param_value_trim(&xval, hbp, &cp)) {
 307          default:
 308             emsg = (c == '*') ? N_("invalid value encoding")/* XXX fake */
 309                   : N_("faulty value - missing closing quotation mark \"\"\"?");
 310             goto jerr;
 311          case -1:
 312             /* XXX if (np->is_enc && memchr(np->dat, '\'', i) != NULL) {
 313              * XXX    emsg = N_("character set info not allowed here");
 314              * XXX    goto jerr;
 315              * XXX } */np->rj_is_enc = FAL0; /* Silently ignore */
 316             /* FALLTHRU */
 317          case 1:
 318             if (xval.l >= UI32_MAX) {
 319                emsg = N_("parameter value too long");
 320                goto jerr;
 321             }
 322             np->rj_len = (ui32_t)xval.l;
 323             np->rj_dat = xval.s;
 324             break;
 325          }
 326
 327          /* Watch out for character set and language info */
 328          if (np->rj_is_enc && (eptr = memchr(xval.s, '\'', xval.l)) != NULL) {
 329             np->rj_cs_len = PTR2SIZE(eptr - xval.s);
 330             if ((eptr = memchr(eptr + 1, '\'', xval.l - np->rj_cs_len - 1))
 331                   == NULL) {
 332                emsg = N_("faulty RFC 2231 parameter extension");
 333                goto jerr;
 334             }
 335             np->rj_val_off = PTR2SIZE(++eptr - xval.s);
 336          }
 337
 338          hbp = cp;
 339       } else
 340          hbp = _mime_param_skip(hbp);
 341    }
 342    assert(head != NULL); /* (always true due to jumpin:, but..) */
 343
 344    errors |= __rfc2231_join(head, &rv, &emsg);
 345    if (errors && (options & OPT_D_VV)) {
 346       /* TODO 1. we need our error ring; 2. such errors in particular
 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 \"%s\" RFC 2231 MIME parameter value: %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 = (iconv_t)-1;/* XXX pacify compiler */
 389 #endif
 390    NYD2_ENTER;
 391
 392 #ifdef HAVE_ICONV
 393    if (head->rj_is_enc) {
 394       char const *tcs;
 395
 396       f |= _HAVE_ENC;
 397       if (head->rj_cs_len == 0) {
 398          /* It is an error if the character set is not set, the language alone
 399           * cannot convert characters, let aside that we don't use it at all */
 400          *emsg = N_("MIME RFC 2231 invalidity: missing character set\n");
 401          f |= _ERRORS;
 402       } else if (ascncasecmp(tcs = charset_get_lc(),
 403             head->rj_dat, head->rj_cs_len)) {
 404          char *cs = ac_alloc(head->rj_cs_len +1);
 405
 406          memcpy(cs, head->rj_dat, head->rj_cs_len);
 407          cs[head->rj_cs_len] = '\0';
 408          if ((fhicd = n_iconv_open(tcs, cs)) != (iconv_t)-1)
 409             f |= _HAVE_ICONV;
 410          else {
 411             *emsg = N_("necessary character set conversion missing");
 412             f |= _ERRORS;
 413          }
 414          ac_free(cs);
 415       }
 416    }
 417 #endif
 418
 419    if (head->rj_no != 0) {
 420       if (!(f & _ERRORS))
 421          *emsg = N_("First RFC 2231 parameter value chunk number is not 0");
 422       f |= _ERRORS;
 423    }
 424
 425    for (sou.s = NULL, sou.l = 0, no = 0; (np = head) != NULL; free(np)) {
 426       head = np->rj_next;
 427
 428       if (np->rj_no != no++) {
 429          if (!(f & _ERRORS))
 430             *emsg = N_("RFC 2231 parameter value chunks are not contiguous");
 431          f |= _ERRORS;
 432       }
 433
 434       /* RFC 2231 allows such info only in the first continuation, and
 435        * furthermore MUSTs the first to be encoded, then */
 436       if (/*np->rj_is_enc &&*/ np->rj_val_off > 0 &&
 437             (f & (_HAVE_ENC | _SEEN_ANY)) != _HAVE_ENC) {
 438          if (!(f & _ERRORS))
 439             *emsg = N_("invalid redundant RFC 2231 charset/language ignored");
 440          f |= _ERRORS;
 441       }
 442       f |= _SEEN_ANY;
 443
 444       i = np->rj_len - np->rj_val_off;
 445       if (!np->rj_is_enc) {
 446          n_str_add_buf(&sou, np->rj_dat + np->rj_val_off, i);
 447          continue;
 448       }
 449
 450       /* Always perform percent decoding */
 451       sin.s = smalloc(i +1);
 452       sin.l = 0;
 453       for (cp = np->rj_dat + np->rj_val_off; i > 0;) {
 454          char c;
 455
 456          if ((c = *cp++) == '%') {
 457             si32_t cc;
 458
 459             if (i < 3 || (cc = mime_hexseq_to_char(cp)) < 0) {
 460                if (!(f & _ERRORS))
 461                   *emsg = N_("invalid RFC 2231 percent encoded sequence");
 462                f |= _ERRORS;
 463                goto jhex_putc;
 464             }
 465             sin.s[sin.l++] = (char)cc;
 466             cp += 2;
 467             i -= 3;
 468          } else {
 469 jhex_putc:
 470             sin.s[sin.l++] = c;
 471             --i;
 472          }
 473       }
 474       sin.s[sin.l] = '\0';
 475
 476       /* And add character set conversion on top as necessary.
 477        * RFC 2231 is pragmatic: encode only mentions percent encoding and the
 478        * character set for the entire string ("[no] facility for using more
 479        * than one character set or language"), therefore "continuations may
 480        * contain a mixture of encoded and unencoded segments" applies to
 481        * a contiguous string of a single character set that has been torn in
 482        * pieces due to space restrictions, and it happened that some pieces
 483        * didn't need to be percent encoded.
 484        *
 485        * _In particular_ it therefore doesn't repeat the RFC 2047 paradigm
 486        * that encoded-words-are-atomic, meaning that a single character-set
 487        * conversion run over the final, joined, partially percent-decoded value
 488        * should be sufficient */
 489 #ifdef HAVE_ICONV
 490       if (f & _HAVE_ICONV) {
 491          struct str sio = {NULL, 0}; /* TODO string pool */
 492
 493          if (n_iconv_str(fhicd, &sio, &sin, NULL, TRU1) != 0) {
 494             n_iconv_reset(fhicd);
 495             if (!(f & _ERRORS))
 496                *emsg = N_("character set conversion failed on value");
 497             f |= _ERRORS;
 498             n_str_add_buf(&sio, "?", 1);
 499          }
 500          free(sin.s);
 501          sin = sio;
 502       }
 503 #endif
 504
 505       n_str_add_buf(&sou, sin.s, sin.l);
 506       free(sin.s);
 507    }
 508
 509 #ifdef HAVE_ICONV
 510    if ((f & _HAVE_ICONV) && /* XXX pacify compiler */ fhicd != (iconv_t)-1)
 511       n_iconv_close(fhicd);
 512 #endif
 513    memcpy(*result = salloc(sou.l +1), sou.s, sou.l +1);
 514    free(sou.s);
 515    NYD2_LEAVE;
 516    return ((f & _ERRORS) != 0);
 517 }
 518
 519 static void
 520 _mime_param_create(struct mime_param_builder *self)
 521 {
 522    struct mime_param_builder next;
 523    /* Don't use MIME_LINELEN_(MAX|LIMIT) stack buffer sizes: normally we won't
 524     * exceed plain MIME_LINELEN, so that this would be a factor 10 wastage.
 525     * On the other hand we may excess _LINELEN to avoid breaking up possible
 526     * multibyte sequences until sizeof(buf) is reached, but since we (a) don't
 527     * support stateful encodings and (b) will try to synchronize on UTF-8 this
 528     * problem is scarce, possibly even artificial */
 529    char buf[MIN(MIME_LINELEN_MAX >> 1, MIME_LINELEN * 2)],
 530       *bp, *bp_max, *bp_xmax, *bp_lanoenc;
 531    char const *vb, *vb_lanoenc;
 532    size_t vl;
 533    enum {
 534       _NONE    = 0,
 535       _ISENC   = 1<<0,
 536       _HADRAW  = 1<<1,
 537       _RAW     = 1<<2
 538    } f = _NONE;
 539    NYD2_ENTER;
 540    LCTA(sizeof(buf) >= MIME_LINELEN * 2);
 541
 542 jneed_enc:
 543    self->mpb_buf = bp = bp_lanoenc = buf;
 544    self->mpb_buf_len = 0;
 545    self->mpb_is_enc = ((f & _ISENC) != 0);
 546    vb_lanoenc = vb = self->mpb_value;
 547    vl = self->mpb_value_len;
 548
 549    /* Configure bp_max to fit in SHOULD, bp_xmax to extent */
 550    bp_max = (buf + MIME_LINELEN) -
 551          (1 + self->mpb_name_len + sizeof("*999*='';") -1 + 2);
 552    bp_xmax = (buf + sizeof(buf)) -
 553          (1 + self->mpb_name_len + sizeof("*999*='';") -1 + 2);
 554    if ((f & _ISENC) && self->mpb_level == 0) {
 555       bp_max -= self->mpb_charset_len;
 556       bp_xmax -= self->mpb_charset_len;
 557    }
 558    if (PTRCMP(bp_max, <=, buf + sizeof("Hunky Dory"))) {
 559       DBG( n_alert("_mime_param_create(): Hunky Dory!"); )
 560       bp_max = buf + (MIME_LINELEN >> 1); /* And then it is SHOULD, anyway */
 561    }
 562    assert(PTRCMP(bp_max + (4 * 3), <=, bp_xmax)); /* UTF-8 extra pad, below */
 563
 564    f &= _ISENC;
 565    while (vl > 0) {
 566       union {char c; ui8_t uc;} u; u.c = *vb;
 567
 568       f |= _RAW;
 569       if (!(f & _ISENC)) {
 570          if (u.uc > 0x7F || cntrlchar(u.c)) { /* XXX reject cntrlchar? */
 571             /* We need to percent encode this character, possibly changing
 572              * overall strategy, but anyway the one of this level, possibly
 573              * rendering invalid any output byte we yet have produced here.
 574              * Instead of throwing away that work just recurse if some fancy
 575              * magic condition is true */
 576              /* *However*, many tested MUAs fail to deal with parameters that
 577               * are splitted across "too many" fields, including ones that
 578               * misread RFC 2231 to allow only one digit, i.e., a maximum of
 579               * ten.  This is plain wrong, but that won't help their users */
 580             if (PTR2SIZE(bp - buf) > /*10 (strawberry) COMPAT*/MIME_LINELEN>>1)
 581                goto jrecurse;
 582             f |= _ISENC;
 583             goto jneed_enc;
 584          }
 585
 586          if (u.uc == '"' || u.uc == '\\') {
 587             f ^= _RAW;
 588             bp[0] = '\\';
 589             bp[1] = u.c;
 590             bp += 2;
 591          }
 592       } else if (u.uc > 0x7F || _rfc2231_etab[u.uc]) {
 593          f ^= _RAW;
 594          bp[0] = '%';
 595          mime_char_to_hexseq(bp + 1, u.c);
 596          bp += 3;
 597       }
 598
 599       ++vb;
 600       --vl;
 601       if (f & _RAW) {
 602          f |= _HADRAW;
 603          vb_lanoenc = vb;
 604          *bp++ = u.c;
 605          bp_lanoenc = bp;
 606       }
 607
 608       /* If all available space has been consumed we must split.
 609        * Due to compatibility reasons we must take care not to break up
 610        * multibyte sequences -- even though RFC 2231 rather implies that the
 611        * splitted value should be joined (after percent encoded fields have
 612        * been percent decoded) and the resulting string be treated in the
 613        * specified character set / language, MUAs have been seen which apply
 614        * the RFC 2047 encoded-words-are-atomic even to RFC 2231 values, even
 615        * if stateful encodings cannot truly be supported like that?!..
 616        *
 617        * So split at 7-bit character if we have seen any and the wastage isn't
 618        * too large; recall that we need to keep the overall number of P=V
 619        * values as low as possible due to compatibility reasons.
 620        * If we haven't seen any plain bytes be laxe and realize that bp_max
 621        * reflects SHOULD lines, and try to extend this as long as possible.
 622        * However, with UTF-8, try to backward synchronize on sequence start */
 623       if (bp <= bp_max)
 624          continue;
 625
 626       if ((f & _HADRAW) && (PTRCMP(bp - bp_lanoenc, <=, bp_lanoenc - buf) ||
 627             (!self->mpb_is_utf8 &&
 628              PTR2SIZE(bp_lanoenc - buf) >= (MIME_LINELEN >> 2)))) {
 629          bp = bp_lanoenc;
 630          vl += PTR2SIZE(vb - vb_lanoenc);
 631          vb = vb_lanoenc;
 632          goto jrecurse;
 633       }
 634
 635       if (self->mpb_is_utf8 && ((ui8_t)(vb[-1]) & 0xC0) != 0x80) {
 636          bp -= 3;
 637          --vb;
 638          ++vl;
 639          goto jrecurse;
 640       }
 641
 642       if (bp <= bp_xmax)
 643          continue;
 644       /* (Shit.) */
 645       goto jrecurse;
 646    }
 647
 648    /* That level made the great and completed encoding.  Build result */
 649    self->mpb_is_enc = ((f & _ISENC) != 0);
 650    self->mpb_buf_len = PTR2SIZE(bp - buf);
 651    __mime_param_join(self);
 652 jleave:
 653    NYD2_LEAVE;
 654    return;
 655
 656    /* Need to recurse, take care not to excess magical limit of 999 levels */
 657 jrecurse:
 658    if (self->mpb_level == 999) {
 659       if (options & OPT_D_VV)
 660          n_err(_("Message RFC 2231 parameters nested too deeply!\n"));
 661       goto jleave;
 662    }
 663
 664    self->mpb_is_enc = ((f & _ISENC) != 0);
 665    self->mpb_buf_len = PTR2SIZE(bp - buf);
 666
 667    memset(&next, 0, sizeof next);
 668    next.mpb_next = self;
 669    next.mpb_level = self->mpb_level + 1;
 670    next.mpb_name_len = self->mpb_name_len;
 671    next.mpb_value_len = vl;
 672    next.mpb_is_utf8 = self->mpb_is_utf8;
 673    next.mpb_name = self->mpb_name;
 674    next.mpb_value = vb;
 675    _mime_param_create(&next);
 676    goto jleave;
 677 }
 678
 679 static void
 680 __mime_param_join(struct mime_param_builder *head)
 681 {
 682    char nobuf[16];
 683    struct mime_param_builder *np;
 684    size_t i, ll;  DBG( size_t len_max; )
 685    struct str *result;
 686    char *cp;
 687    enum {
 688       _NONE    = 0,
 689       _ISENC   = 1<<0,
 690       _ISQUOTE = 1<<1,
 691       _ISCONT  = 1<<2
 692    } f = _NONE;
 693    NYD2_ENTER;
 694
 695    /* Traverse the stack upwards to find out result length (worst case).
 696     * Reverse the list while doing so */
 697    for (i = 0, np = head, head = NULL; np != NULL;) {
 698       struct mime_param_builder *tmp;
 699
 700       i += np->mpb_buf_len + np->mpb_name_len + sizeof(" *999*=\"\";\n") -1;
 701       if (np->mpb_is_enc)
 702          f |= _ISENC;
 703
 704       tmp = np->mpb_next;
 705       np->mpb_next = head;
 706       head = np;
 707       np = tmp;
 708    }
 709    if (f & _ISENC)
 710       i += head->mpb_charset_len; /* sizeof("''") -1 covered by \"\" above */
 711    DBG( len_max = i; )
 712    head->mpb_rv = TRU1;
 713
 714    result = head->mpb_result;
 715    if (head->mpb_next != NULL)
 716       f |= _ISCONT;
 717    cp = result->s = salloc(i +1);
 718
 719    for (ll = 0, np = head;;) {
 720       /* Name part */
 721       memcpy(cp, np->mpb_name, i = np->mpb_name_len);
 722       cp += i;
 723       ll += i;
 724
 725       if (f & _ISCONT) {
 726          char *cpo = cp, *nop = nobuf + sizeof(nobuf);
 727          ui32_t noi = np->mpb_level;
 728
 729          *--nop = '\0';
 730          do
 731             *--nop = "0123456789"[noi % 10];
 732          while ((noi /= 10) != 0);
 733
 734          *cp++ = '*';
 735          while (*nop != '\0')
 736             *cp++ = *nop++;
 737
 738          ll += PTR2SIZE(cp - cpo);
 739       }
 740
 741       if ((f & _ISENC) || np->mpb_is_enc) {
 742          *cp++ = '*';
 743          ++ll;
 744       }
 745       *cp++ = '=';
 746       ++ll;
 747
 748       /* Value part */
 749       if (f & _ISENC) {
 750          f &= ~_ISENC;
 751          memcpy(cp, np->mpb_charset, i = np->mpb_charset_len);
 752          cp += i;
 753          cp[0] = '\'';
 754          cp[1] = '\'';
 755          cp += 2;
 756          ll += i + 2;
 757       } else if (!np->mpb_is_enc) {
 758          f |= _ISQUOTE;
 759          *cp++ = '"';
 760          ++ll;
 761       }
 762
 763       memcpy(cp, np->mpb_buf, i = np->mpb_buf_len);
 764       cp += i;
 765       ll += i;
 766
 767       if (f & _ISQUOTE) {
 768          f ^= _ISQUOTE;
 769          *cp++ = '"';
 770          ++ll;
 771       }
 772
 773       if ((np = np->mpb_next) == NULL)
 774          break;
 775       *cp++ = ';';
 776       ++ll;
 777
 778       i = ll;
 779       i += np->mpb_name_len + np->mpb_buf_len + sizeof(" *999*=\"\";\n") -1;
 780       if (i >= MIME_LINELEN) {
 781          head->mpb_rv = -TRU1;
 782          *cp++ = '\n';
 783          ll = 0;
 784       }
 785
 786       *cp++ = ' ';
 787       ++ll;
 788    }
 789    *cp = '\0';
 790    result->l = PTR2SIZE(cp - result->s);
 791    assert(result->l < len_max);
 792    NYD2_LEAVE;
 793 }
 794
 795 FL char *
 796 mime_param_get(char const *param, char const *headerbody) /* TODO rewr. */
 797 {
 798    struct str xval;
 799    char *rv = NULL;
 800    size_t plen;
 801    char const *p;
 802    NYD_ENTER;
 803
 804    plen = strlen(param);
 805    p = headerbody;
 806
 807    /* At the beginning of headerbody there is no parameter=value pair xxx */
 808    if (!whitechar(*p))
 809       goto jskip1st;
 810
 811    for (;;) {
 812       while (whitechar(*p))
 813          ++p;
 814
 815       if (!ascncasecmp(p, param, plen)) {
 816          p += plen;
 817          while (whitechar(*p)) /* XXX? */
 818             ++p;
 819          switch (*p++) {
 820          case '*':
 821             rv = _rfc2231_param_parse(param, plen, p);
 822             goto jleave;
 823          case '=':
 824             if (!_mime_param_value_trim(&xval, p, NULL)) {
 825                /* XXX LOG? */
 826                goto jleave;
 827             }
 828             rv = xval.s;
 829
 830             /* We do have a result, but some (elder) software (S-nail <v14.8)
 831              * will use RFC 2047 encoded words in  parameter values, too */
 832             /* TODO Automatically check wether the value seems to be RFC 2047
 833              * TODO encwd. -- instead use *rfc2047_parameters* like mutt(1)? */
 834             if ((p = strstr(rv, "=?")) != NULL && strstr(p, "?=") != NULL) {
 835                struct str ti, to;
 836
 837                ti.l = strlen(ti.s = rv);
 838                mime_fromhdr(&ti, &to, TD_ISPR | TD_ICONV | TD_DELCTRL);
 839                rv = savestrbuf(to.s, to.l);
 840                free(to.s);
 841             }
 842             goto jleave;
 843          default:
 844             /* Not our desired parameter, skip and continue */
 845             break;
 846          }
 847       }
 848
 849 jskip1st:
 850       if (*(p = _mime_param_skip(p)) == '\0')
 851          goto jleave;
 852    }
 853
 854 jleave:
 855    NYD_LEAVE;
 856    return rv;
 857 }
 858
 859 FL si8_t
 860 mime_param_create(struct str *result, char const *name, char const *value)
 861 {
 862    /* TODO All this needs rework when we have (1) a real string and even more
 863     * TODO (2) use objects instead of stupid string concat; it's temporary
 864     * TODO I.e., this function should return a HeaderBodyParam */
 865    struct mime_param_builder top;
 866    size_t i;
 867    NYD_ENTER;
 868
 869    memset(result, 0, sizeof *result);
 870
 871    memset(&top, 0, sizeof top);
 872    top.mpb_result = result;
 873    if ((i = strlen(top.mpb_name = name)) > UI32_MAX)
 874       goto jleave;
 875    top.mpb_name_len = (ui32_t)i;
 876    if ((i = strlen(top.mpb_value = value)) > UI32_MAX)
 877       goto jleave;
 878    top.mpb_value_len = (ui32_t)i;
 879    top.mpb_charset_len = (ui32_t)strlen(top.mpb_charset = charset_get_lc());
 880    top.mpb_is_utf8 = !ascncasecmp(top.mpb_charset, "utf-8",
 881          top.mpb_charset_len);
 882
 883    _mime_param_create(&top);
 884 jleave:
 885    NYD_LEAVE;
 886    return top.mpb_rv;
 887 }
 888
 889 FL char *
 890 mime_param_boundary_get(char const *headerbody, size_t *len)
 891 {
 892    char *q = NULL, *p;
 893    NYD_ENTER;
 894
 895    if ((p = mime_param_get("boundary", headerbody)) != NULL) {
 896       size_t sz = strlen(p);
 897
 898       if (len != NULL)
 899          *len = sz + 2;
 900       q = salloc(sz + 2 +1);
 901       q[0] = q[1] = '-';
 902       memcpy(q + 2, p, sz);
 903       *(q + sz + 2) = '\0';
 904    }
 905    NYD_LEAVE;
 906    return q;
 907 }
 908
 909 FL char *
 910 mime_param_boundary_create(void)
 911 {
 912    char *bp;
 913    NYD_ENTER;
 914
 915    bp = salloc(36 + 6 +1);
 916    bp[0] = bp[2] = bp[39] = bp[41] = '=';
 917    bp[1] = bp[40] = '-';
 918    memcpy(bp + 3, getrandstring(36), 36);
 919    bp[42] = '\0';
 920    NYD_LEAVE;
 921    return bp;
 922 }
 923
 924 /* s-it-mode */