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      1 /*	$NetBSD: gen_decode.c,v 1.3 2023/06/19 21:41:42 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1997 - 2006 Kungliga Tekniska Hgskolan
      5  * (Royal Institute of Technology, Stockholm, Sweden).
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  *
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  *
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * 3. Neither the name of the Institute nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include "gen_locl.h"
     37 #include "lex.h"
     38 
     39 __RCSID("$NetBSD: gen_decode.c,v 1.3 2023/06/19 21:41:42 christos Exp $");
     40 
     41 static void
     42 decode_primitive (const char *typename, const char *name, const char *forwstr)
     43 {
     44 #if 0
     45     fprintf (codefile,
     46 	     "e = decode_%s(p, len, %s, &l);\n"
     47 	     "%s;\n",
     48 	     typename,
     49 	     name,
     50 	     forwstr);
     51 #else
     52     fprintf (codefile,
     53 	     "e = der_get_%s(p, len, %s, &l);\n"
     54 	     "if(e) %s;\np += l; len -= l; ret += l;\n",
     55 	     typename,
     56 	     name,
     57 	     forwstr);
     58 #endif
     59 }
     60 
     61 static void
     62 find_tag (const Type *t,
     63 	  Der_class *cl, Der_type *ty, unsigned *tag)
     64 {
     65     switch (t->type) {
     66     case TBitString:
     67 	*cl  = ASN1_C_UNIV;
     68 	*ty  = PRIM;
     69 	*tag = UT_BitString;
     70 	break;
     71     case TBoolean:
     72 	*cl  = ASN1_C_UNIV;
     73 	*ty  = PRIM;
     74 	*tag = UT_Boolean;
     75 	break;
     76     case TChoice:
     77 	errx(1, "Cannot have recursive CHOICE");
     78     case TEnumerated:
     79 	*cl  = ASN1_C_UNIV;
     80 	*ty  = PRIM;
     81 	*tag = UT_Enumerated;
     82 	break;
     83     case TGeneralString:
     84 	*cl  = ASN1_C_UNIV;
     85 	*ty  = PRIM;
     86 	*tag = UT_GeneralString;
     87 	break;
     88     case TTeletexString:
     89 	*cl  = ASN1_C_UNIV;
     90 	*ty  = PRIM;
     91 	*tag = UT_TeletexString;
     92 	break;
     93     case TGeneralizedTime:
     94 	*cl  = ASN1_C_UNIV;
     95 	*ty  = PRIM;
     96 	*tag = UT_GeneralizedTime;
     97 	break;
     98     case TIA5String:
     99 	*cl  = ASN1_C_UNIV;
    100 	*ty  = PRIM;
    101 	*tag = UT_IA5String;
    102 	break;
    103     case TInteger:
    104 	*cl  = ASN1_C_UNIV;
    105 	*ty  = PRIM;
    106 	*tag = UT_Integer;
    107 	break;
    108     case TNull:
    109 	*cl  = ASN1_C_UNIV;
    110 	*ty  = PRIM;
    111 	*tag = UT_Null;
    112 	break;
    113     case TOID:
    114 	*cl  = ASN1_C_UNIV;
    115 	*ty  = PRIM;
    116 	*tag = UT_OID;
    117 	break;
    118     case TOctetString:
    119 	*cl  = ASN1_C_UNIV;
    120 	*ty  = PRIM;
    121 	*tag = UT_OctetString;
    122 	break;
    123     case TPrintableString:
    124 	*cl  = ASN1_C_UNIV;
    125 	*ty  = PRIM;
    126 	*tag = UT_PrintableString;
    127 	break;
    128     case TSequence:
    129     case TSequenceOf:
    130 	*cl  = ASN1_C_UNIV;
    131 	*ty  = CONS;
    132 	*tag = UT_Sequence;
    133 	break;
    134     case TSet:
    135     case TSetOf:
    136 	*cl  = ASN1_C_UNIV;
    137 	*ty  = CONS;
    138 	*tag = UT_Set;
    139 	break;
    140     case TTag:
    141 	*cl  = t->tag.tagclass;
    142 	*ty  = is_primitive_type(t->subtype->type) ? PRIM : CONS;
    143 	*tag = t->tag.tagvalue;
    144 	break;
    145     case TType:
    146 	if ((t->symbol->stype == Stype && t->symbol->type == NULL)
    147 	    || t->symbol->stype == SUndefined) {
    148 	    lex_error_message("%s is imported or still undefined, "
    149 			      " can't generate tag checking data in CHOICE "
    150 			      "without this information",
    151 			      t->symbol->name);
    152 	    exit(1);
    153 	}
    154 	find_tag(t->symbol->type, cl, ty, tag);
    155 	return;
    156     case TUTCTime:
    157 	*cl  = ASN1_C_UNIV;
    158 	*ty  = PRIM;
    159 	*tag = UT_UTCTime;
    160 	break;
    161     case TUTF8String:
    162 	*cl  = ASN1_C_UNIV;
    163 	*ty  = PRIM;
    164 	*tag = UT_UTF8String;
    165 	break;
    166     case TBMPString:
    167 	*cl  = ASN1_C_UNIV;
    168 	*ty  = PRIM;
    169 	*tag = UT_BMPString;
    170 	break;
    171     case TUniversalString:
    172 	*cl  = ASN1_C_UNIV;
    173 	*ty  = PRIM;
    174 	*tag = UT_UniversalString;
    175 	break;
    176     case TVisibleString:
    177 	*cl  = ASN1_C_UNIV;
    178 	*ty  = PRIM;
    179 	*tag = UT_VisibleString;
    180 	break;
    181     default:
    182 	abort();
    183     }
    184 }
    185 
    186 static void
    187 range_check(const char *name,
    188 	    const char *length,
    189 	    const char *forwstr,
    190 	    struct range *r)
    191 {
    192     if (r->min == r->max + 2 || r->min < r->max)
    193 	fprintf (codefile,
    194 		 "if ((%s)->%s > %lld) {\n"
    195 		 "e = ASN1_MAX_CONSTRAINT; %s;\n"
    196 		 "}\n",
    197 		 name, length, (long long)r->max, forwstr);
    198     if ((r->min - 1 == r->max || r->min < r->max) && r->min > 0)
    199 	fprintf (codefile,
    200 		 "if ((%s)->%s < %lld) {\n"
    201 		 "e = ASN1_MIN_CONSTRAINT; %s;\n"
    202 		 "}\n",
    203 		 name, length, (long long)r->min, forwstr);
    204     if (r->max == r->min)
    205 	fprintf (codefile,
    206 		 "if ((%s)->%s != %lld) {\n"
    207 		 "e = ASN1_EXACT_CONSTRAINT; %s;\n"
    208 		 "}\n",
    209 		 name, length, (long long)r->min, forwstr);
    210 }
    211 
    212 static int
    213 decode_type (const char *name, const Type *t, int optional,
    214 	     const char *forwstr, const char *tmpstr, const char *dertype,
    215 	     unsigned int depth)
    216 {
    217     switch (t->type) {
    218     case TType: {
    219 	if (optional)
    220 	    fprintf(codefile,
    221 		    "%s = calloc(1, sizeof(*%s));\n"
    222 		    "if (%s == NULL) %s;\n",
    223 		    name, name, name, forwstr);
    224 	fprintf (codefile,
    225 		 "e = decode_%s(p, len, %s, &l);\n",
    226 		 t->symbol->gen_name, name);
    227 	if (optional) {
    228 	    fprintf (codefile,
    229 		     "if(e) {\n"
    230 		     "free(%s);\n"
    231 		     "%s = NULL;\n"
    232 		     "} else {\n"
    233 		     "p += l; len -= l; ret += l;\n"
    234 		     "}\n",
    235 		     name, name);
    236 	} else {
    237 	    fprintf (codefile,
    238 		     "if(e) %s;\n",
    239 		     forwstr);
    240 	    fprintf (codefile,
    241 		     "p += l; len -= l; ret += l;\n");
    242 	}
    243 	break;
    244     }
    245     case TInteger:
    246 	if(t->members) {
    247 	    /*
    248 	     * This will produce a worning, how its hard to fix since:
    249 	     * if its enum to an NameType, we can add appriate
    250 	     * type-cast. If its not though, we have to figure out if
    251 	     * there is negative enum enum and use appropriate
    252 	     * signness and size on the intertype we cast the result
    253 	     * too.
    254 	     */
    255 	    fprintf(codefile,
    256 		    "{\n"
    257 		    "int enumint;\n");
    258 	    decode_primitive ("integer", "&enumint", forwstr);
    259 	    fprintf(codefile,
    260 		    "*%s = enumint;\n"
    261 		    "}\n",
    262 		    name);
    263 	} else if (t->range == NULL) {
    264 	    decode_primitive ("heim_integer", name, forwstr);
    265 	} else if (t->range->min < INT_MIN && t->range->max <= INT64_MAX) {
    266 	    decode_primitive ("integer64", name, forwstr);
    267 	} else if (t->range->min >= 0 && t->range->max > UINT_MAX) {
    268 	    decode_primitive ("unsigned64", name, forwstr);
    269 	} else if (t->range->min >= INT_MIN && t->range->max <= INT_MAX) {
    270 	    decode_primitive ("integer", name, forwstr);
    271 	} else if (t->range->min >= 0 && t->range->max <= UINT_MAX) {
    272 	    decode_primitive ("unsigned", name, forwstr);
    273 	} else
    274 	    errx(1, "%s: unsupported range %lld -> %lld",
    275 		 name, (long long)t->range->min, (long long)t->range->max);
    276 	break;
    277     case TBoolean:
    278       decode_primitive ("boolean", name, forwstr);
    279       break;
    280     case TEnumerated:
    281 	decode_primitive ("enumerated", name, forwstr);
    282 	break;
    283     case TOctetString:
    284 	if (dertype) {
    285 	    fprintf(codefile,
    286 		    "if (%s == CONS) {\n",
    287 		    dertype);
    288 	    decode_primitive("octet_string_ber", name, forwstr);
    289 	    fprintf(codefile,
    290 		    "} else {\n");
    291 	}
    292 	decode_primitive ("octet_string", name, forwstr);
    293 	if (dertype)
    294 	    fprintf(codefile, "}\n");
    295 	if (t->range)
    296 	    range_check(name, "length", forwstr, t->range);
    297 	break;
    298     case TBitString: {
    299 	Member *m;
    300 	int pos = 0;
    301 
    302 	if (ASN1_TAILQ_EMPTY(t->members)) {
    303 	    decode_primitive ("bit_string", name, forwstr);
    304 	    break;
    305 	}
    306 	fprintf(codefile,
    307 		"if (len < 1) return ASN1_OVERRUN;\n"
    308 		"p++; len--; ret++;\n");
    309 	fprintf(codefile,
    310 		"do {\n"
    311 		"if (len < 1) break;\n");
    312 	ASN1_TAILQ_FOREACH(m, t->members, members) {
    313 	    while (m->val / 8 > pos / 8) {
    314 		fprintf (codefile,
    315 			 "p++; len--; ret++;\n"
    316 			 "if (len < 1) break;\n");
    317 		pos += 8;
    318 	    }
    319 	    fprintf (codefile,
    320 		     "(%s)->%s = (*p >> %d) & 1;\n",
    321 		     name, m->gen_name, 7 - m->val % 8);
    322 	}
    323 	fprintf(codefile,
    324 		"} while(0);\n");
    325 	fprintf (codefile,
    326 		 "p += len; ret += len;\n");
    327 	break;
    328     }
    329     case TSequence: {
    330 	Member *m;
    331 
    332 	if (t->members == NULL)
    333 	    break;
    334 
    335 	ASN1_TAILQ_FOREACH(m, t->members, members) {
    336 	    char *s = NULL;
    337 
    338 	    if (m->ellipsis)
    339 		continue;
    340 
    341 	    if (asprintf (&s, "%s(%s)->%s", m->optional ? "" : "&",
    342 			  name, m->gen_name) < 0 || s == NULL)
    343 		errx(1, "malloc");
    344 	    decode_type (s, m->type, m->optional, forwstr, m->gen_name, NULL,
    345 		depth + 1);
    346 	    free (s);
    347 	}
    348 
    349 	break;
    350     }
    351     case TSet: {
    352 	Member *m;
    353 	unsigned int memno;
    354 
    355 	if(t->members == NULL)
    356 	    break;
    357 
    358 	fprintf(codefile, "{\n");
    359 	fprintf(codefile, "unsigned int members = 0;\n");
    360 	fprintf(codefile, "while(len > 0) {\n");
    361 	fprintf(codefile,
    362 		"Der_class class;\n"
    363 		"Der_type type;\n"
    364 		"int tag;\n"
    365 		"e = der_get_tag (p, len, &class, &type, &tag, NULL);\n"
    366 		"if(e) %s;\n", forwstr);
    367 	fprintf(codefile, "switch (MAKE_TAG(class, type, tag)) {\n");
    368 	memno = 0;
    369 	ASN1_TAILQ_FOREACH(m, t->members, members) {
    370 	    char *s;
    371 
    372 	    assert(m->type->type == TTag);
    373 
    374 	    fprintf(codefile, "case MAKE_TAG(%s, %s, %s):\n",
    375 		    classname(m->type->tag.tagclass),
    376 		    is_primitive_type(m->type->subtype->type) ? "PRIM" : "CONS",
    377 		    valuename(m->type->tag.tagclass, m->type->tag.tagvalue));
    378 
    379 	    if (asprintf (&s, "%s(%s)->%s", m->optional ? "" : "&", name, m->gen_name) < 0 || s == NULL)
    380 		errx(1, "malloc");
    381 	    if(m->optional)
    382 		fprintf(codefile,
    383 			"%s = calloc(1, sizeof(*%s));\n"
    384 			"if (%s == NULL) { e = ENOMEM; %s; }\n",
    385 			s, s, s, forwstr);
    386 	    decode_type (s, m->type, 0, forwstr, m->gen_name, NULL, depth + 1);
    387 	    free (s);
    388 
    389 	    fprintf(codefile, "members |= (1 << %d);\n", memno);
    390 	    memno++;
    391 	    fprintf(codefile, "break;\n");
    392 	}
    393 	fprintf(codefile,
    394 		"default:\n"
    395 		"return ASN1_MISPLACED_FIELD;\n"
    396 		"break;\n");
    397 	fprintf(codefile, "}\n");
    398 	fprintf(codefile, "}\n");
    399 	memno = 0;
    400 	ASN1_TAILQ_FOREACH(m, t->members, members) {
    401 	    char *s;
    402 
    403 	    if (asprintf (&s, "%s->%s", name, m->gen_name) < 0 || s == NULL)
    404 		errx(1, "malloc");
    405 	    fprintf(codefile, "if((members & (1 << %d)) == 0)\n", memno);
    406 	    if(m->optional)
    407 		fprintf(codefile, "%s = NULL;\n", s);
    408 	    else if(m->defval)
    409 		gen_assign_defval(s, m->defval);
    410 	    else
    411 		fprintf(codefile, "return ASN1_MISSING_FIELD;\n");
    412 	    free(s);
    413 	    memno++;
    414 	}
    415 	fprintf(codefile, "}\n");
    416 	break;
    417     }
    418     case TSetOf:
    419     case TSequenceOf: {
    420 	char *n = NULL;
    421 	char *sname = NULL;
    422 
    423 	fprintf (codefile,
    424 		 "{\n"
    425 		 "size_t %s_origlen = len;\n"
    426 		 "size_t %s_oldret = ret;\n"
    427 		 "size_t %s_olen = 0;\n"
    428 		 "void *%s_tmp;\n"
    429 		 "ret = 0;\n"
    430 		 "(%s)->len = 0;\n"
    431 		 "(%s)->val = NULL;\n",
    432 		 tmpstr,
    433 		 tmpstr,
    434 		 tmpstr,
    435 		 tmpstr,
    436 		 name,
    437 		 name);
    438 
    439 	fprintf (codefile,
    440 		 "while(ret < %s_origlen) {\n"
    441 		 "size_t %s_nlen = %s_olen + sizeof(*((%s)->val));\n"
    442 		 "if (%s_olen > %s_nlen) { e = ASN1_OVERFLOW; %s; }\n"
    443 		 "%s_olen = %s_nlen;\n"
    444 		 "%s_tmp = realloc((%s)->val, %s_olen);\n"
    445 		 "if (%s_tmp == NULL) { e = ENOMEM; %s; }\n"
    446 		 "(%s)->val = %s_tmp;\n",
    447 		 tmpstr,
    448 		 tmpstr, tmpstr, name,
    449 		 tmpstr, tmpstr, forwstr,
    450 		 tmpstr, tmpstr,
    451 		 tmpstr, name, tmpstr,
    452 		 tmpstr, forwstr,
    453 		 name, tmpstr);
    454 
    455 	if (asprintf (&n, "&(%s)->val[(%s)->len]", name, name) < 0 || n == NULL)
    456 	    errx(1, "malloc");
    457 	if (asprintf (&sname, "%s_s_of", tmpstr) < 0 || sname == NULL)
    458 	    errx(1, "malloc");
    459 	decode_type (n, t->subtype, 0, forwstr, sname, NULL, depth + 1);
    460 	fprintf (codefile,
    461 		 "(%s)->len++;\n"
    462 		 "len = %s_origlen - ret;\n"
    463 		 "}\n"
    464 		 "ret += %s_oldret;\n"
    465 		 "}\n",
    466 		 name,
    467 		 tmpstr, tmpstr);
    468 	if (t->range)
    469 	    range_check(name, "len", forwstr, t->range);
    470 	free (n);
    471 	free (sname);
    472 	break;
    473     }
    474     case TGeneralizedTime:
    475 	decode_primitive ("generalized_time", name, forwstr);
    476 	break;
    477     case TGeneralString:
    478 	decode_primitive ("general_string", name, forwstr);
    479 	break;
    480     case TTeletexString:
    481 	decode_primitive ("general_string", name, forwstr);
    482 	break;
    483     case TTag:{
    484     	char *tname = NULL, *typestring = NULL;
    485 	char *ide = NULL;
    486 
    487 	if (asprintf(&typestring, "%s_type", tmpstr) < 0 || typestring == NULL)
    488 	    errx(1, "malloc");
    489 
    490 	fprintf(codefile,
    491 		"{\n"
    492 		"size_t %s_datalen, %s_oldlen;\n"
    493 		"Der_type %s;\n",
    494 		tmpstr, tmpstr, typestring);
    495 	if(support_ber)
    496 	    fprintf(codefile,
    497 		    "int is_indefinite%u;\n", depth);
    498 
    499 	fprintf(codefile, "e = der_match_tag_and_length(p, len, %s, &%s, %s, "
    500 		"&%s_datalen, &l);\n",
    501 		classname(t->tag.tagclass),
    502 		typestring,
    503 		valuename(t->tag.tagclass, t->tag.tagvalue),
    504 		tmpstr);
    505 
    506 	/* XXX hardcode for now */
    507 	if (support_ber && t->subtype->type == TOctetString) {
    508 	    ide = typestring;
    509 	} else {
    510 	    fprintf(codefile,
    511 		    "if (e == 0 && %s != %s) { e = ASN1_BAD_ID; }\n",
    512 		    typestring,
    513 		    is_primitive_type(t->subtype->type) ? "PRIM" : "CONS");
    514 	}
    515 
    516 	if(optional) {
    517 	    fprintf(codefile,
    518 		    "if(e) {\n"
    519 		    "%s = NULL;\n"
    520 		    "} else {\n"
    521 		     "%s = calloc(1, sizeof(*%s));\n"
    522 		     "if (%s == NULL) { e = ENOMEM; %s; }\n",
    523 		     name, name, name, name, forwstr);
    524 	} else {
    525 	    fprintf(codefile, "if(e) %s;\n", forwstr);
    526 	}
    527 	fprintf (codefile,
    528 		 "p += l; len -= l; ret += l;\n"
    529 		 "%s_oldlen = len;\n",
    530 		 tmpstr);
    531 	if(support_ber)
    532 	    fprintf (codefile,
    533 		     "if((is_indefinite%u = _heim_fix_dce(%s_datalen, &len)) < 0)\n"
    534 		     "{ e = ASN1_BAD_FORMAT; %s; }\n"
    535 		     "if (is_indefinite%u) { if (len < 2) { e = ASN1_OVERRUN; %s; } len -= 2; }",
    536 		     depth, tmpstr, forwstr, depth, forwstr);
    537 	else
    538 	    fprintf(codefile,
    539 		    "if (%s_datalen > len) { e = ASN1_OVERRUN; %s; }\n"
    540 		    "len = %s_datalen;\n", tmpstr, forwstr, tmpstr);
    541 	if (asprintf (&tname, "%s_Tag", tmpstr) < 0 || tname == NULL)
    542 	    errx(1, "malloc");
    543 	decode_type (name, t->subtype, 0, forwstr, tname, ide, depth + 1);
    544 	if(support_ber)
    545 	    fprintf(codefile,
    546 		    "if(is_indefinite%u){\n"
    547 		    "len += 2;\n"
    548 		    "e = der_match_tag_and_length(p, len, "
    549 		    "(Der_class)0, &%s, UT_EndOfContent, "
    550 		    "&%s_datalen, &l);\n"
    551 		    "if(e) %s;\n"
    552 		    "p += l; len -= l; ret += l;\n"
    553 		    "if (%s != (Der_type)0) { e = ASN1_BAD_ID; %s; }\n"
    554 		    "} else \n",
    555 		    depth,
    556 		    typestring,
    557 		    tmpstr,
    558 		    forwstr,
    559 		    typestring, forwstr);
    560 	fprintf(codefile,
    561 		"len = %s_oldlen - %s_datalen;\n",
    562 		tmpstr, tmpstr);
    563 	if(optional)
    564 	    fprintf(codefile,
    565 		    "}\n");
    566 	fprintf(codefile,
    567 		"}\n");
    568 	free(tname);
    569 	free(typestring);
    570 	break;
    571     }
    572     case TChoice: {
    573 	Member *m, *have_ellipsis = NULL;
    574 	const char *els = "";
    575 
    576 	if (t->members == NULL)
    577 	    break;
    578 
    579 	ASN1_TAILQ_FOREACH(m, t->members, members) {
    580 	    const Type *tt = m->type;
    581 	    char *s = NULL;
    582 	    Der_class cl;
    583 	    Der_type  ty;
    584 	    unsigned  tag;
    585 
    586 	    if (m->ellipsis) {
    587 		have_ellipsis = m;
    588 		continue;
    589 	    }
    590 
    591 	    find_tag(tt, &cl, &ty, &tag);
    592 
    593 	    fprintf(codefile,
    594 		    "%sif (der_match_tag(p, len, %s, %s, %s, NULL) == 0) {\n",
    595 		    els,
    596 		    classname(cl),
    597 		    ty ? "CONS" : "PRIM",
    598 		    valuename(cl, tag));
    599 	    fprintf(codefile,
    600 		    "(%s)->element = %s;\n",
    601 		    name, m->label);
    602 	    if (asprintf (&s, "%s(%s)->u.%s", m->optional ? "" : "&",
    603 			  name, m->gen_name) < 0 || s == NULL)
    604 		errx(1, "malloc");
    605 	    decode_type (s, m->type, m->optional, forwstr, m->gen_name, NULL,
    606 		depth + 1);
    607 	    free(s);
    608 	    fprintf(codefile,
    609 		    "}\n");
    610 	    els = "else ";
    611 	}
    612 	if (have_ellipsis) {
    613 	    fprintf(codefile,
    614 		    "else {\n"
    615 		    "(%s)->element = %s;\n"
    616 		    "(%s)->u.%s.data = calloc(1, len);\n"
    617 		    "if ((%s)->u.%s.data == NULL) {\n"
    618 		    "e = ENOMEM; %s;\n"
    619 		    "}\n"
    620 		    "(%s)->u.%s.length = len;\n"
    621 		    "memcpy((%s)->u.%s.data, p, len);\n"
    622 		    "p += len;\n"
    623 		    "ret += len;\n"
    624 		    "len = 0;\n"
    625 		    "}\n",
    626 		    name, have_ellipsis->label,
    627 		    name, have_ellipsis->gen_name,
    628 		    name, have_ellipsis->gen_name,
    629 		    forwstr,
    630 		    name, have_ellipsis->gen_name,
    631 		    name, have_ellipsis->gen_name);
    632 	} else {
    633 	    fprintf(codefile,
    634 		    "else {\n"
    635 		    "e = ASN1_PARSE_ERROR;\n"
    636 		    "%s;\n"
    637 		    "}\n",
    638 		    forwstr);
    639 	}
    640 	break;
    641     }
    642     case TUTCTime:
    643 	decode_primitive ("utctime", name, forwstr);
    644 	break;
    645     case TUTF8String:
    646 	decode_primitive ("utf8string", name, forwstr);
    647 	break;
    648     case TPrintableString:
    649 	decode_primitive ("printable_string", name, forwstr);
    650 	break;
    651     case TIA5String:
    652 	decode_primitive ("ia5_string", name, forwstr);
    653 	break;
    654     case TBMPString:
    655 	decode_primitive ("bmp_string", name, forwstr);
    656 	break;
    657     case TUniversalString:
    658 	decode_primitive ("universal_string", name, forwstr);
    659 	break;
    660     case TVisibleString:
    661 	decode_primitive ("visible_string", name, forwstr);
    662 	break;
    663     case TNull:
    664 	fprintf (codefile, "/* NULL */\n");
    665 	break;
    666     case TOID:
    667 	decode_primitive ("oid", name, forwstr);
    668 	break;
    669     default :
    670 	abort ();
    671     }
    672     return 0;
    673 }
    674 
    675 void
    676 generate_type_decode (const Symbol *s)
    677 {
    678     int preserve = preserve_type(s->name) ? TRUE : FALSE;
    679 
    680     fprintf (codefile, "int ASN1CALL\n"
    681 	     "decode_%s(const unsigned char *p HEIMDAL_UNUSED_ATTRIBUTE,"
    682 	     " size_t len HEIMDAL_UNUSED_ATTRIBUTE, %s *data, size_t *size)\n"
    683 	     "{\n",
    684 	     s->gen_name, s->gen_name);
    685 
    686     switch (s->type->type) {
    687     case TInteger:
    688     case TBoolean:
    689     case TOctetString:
    690     case TOID:
    691     case TGeneralizedTime:
    692     case TGeneralString:
    693     case TTeletexString:
    694     case TUTF8String:
    695     case TPrintableString:
    696     case TIA5String:
    697     case TBMPString:
    698     case TUniversalString:
    699     case TVisibleString:
    700     case TUTCTime:
    701     case TNull:
    702     case TEnumerated:
    703     case TBitString:
    704     case TSequence:
    705     case TSequenceOf:
    706     case TSet:
    707     case TSetOf:
    708     case TTag:
    709     case TType:
    710     case TChoice:
    711 	fprintf (codefile,
    712 		 "size_t ret = 0;\n"
    713 		 "size_t l HEIMDAL_UNUSED_ATTRIBUTE;\n"
    714 		 "int e HEIMDAL_UNUSED_ATTRIBUTE;\n");
    715 	if (preserve)
    716 	    fprintf (codefile, "const unsigned char *begin = p;\n");
    717 
    718 	fprintf (codefile, "\n");
    719 	fprintf (codefile, "memset(data, 0, sizeof(*data));\n"); /* hack to avoid `unused variable' */
    720 
    721 	decode_type ("data", s->type, 0, "goto fail", "Top", NULL, 1);
    722 	if (preserve)
    723 	    fprintf (codefile,
    724 		     "data->_save.data = calloc(1, ret);\n"
    725 		     "if (data->_save.data == NULL) { \n"
    726 		     "e = ENOMEM; goto fail; \n"
    727 		     "}\n"
    728 		     "data->_save.length = ret;\n"
    729 		     "memcpy(data->_save.data, begin, ret);\n");
    730 	fprintf (codefile,
    731 		 "if(size) *size = ret;\n"
    732 		 "return 0;\n");
    733 	fprintf (codefile,
    734 		 "fail:\n"
    735 		 "free_%s(data);\n"
    736 		 "return e;\n",
    737 		 s->gen_name);
    738 	break;
    739     default:
    740 	abort ();
    741     }
    742     fprintf (codefile, "}\n\n");
    743 }
    744