crypto/conf/conf_def.c

   1 /* crypto/conf/conf.c */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 /* Part of the code in here was originally in conf.c, which is now removed */
  60
  61 #include <stdio.h>
  62 #include <string.h>
  63 #include "cryptlib.h"
  64 #include <openssl/stack.h>
  65 #include <openssl/lhash.h>
  66 #include <openssl/conf.h>
  67 #include <openssl/conf_api.h>
  68 #include "conf_def.h"
  69 #include <openssl/buffer.h>
  70 #include <openssl/err.h>
  71
  72 static char *eat_ws(CONF *conf, char *p);
  73 static char *eat_alpha_numeric(CONF *conf, char *p);
  74 static void clear_comments(CONF *conf, char *p);
  75 static int str_copy(CONF *conf, char *section, char **to, char *from);
  76 static char *scan_quote(CONF *conf, char *p);
  77 static char *scan_dquote(CONF *conf, char *p);
  78 #define scan_esc(conf,p)        (((IS_EOF((conf),(p)[1]))?((p)+1):((p)+2)))
  79
  80 static CONF *def_create(CONF_METHOD *meth);
  81 static int def_init_default(CONF *conf);
  82 static int def_init_WIN32(CONF *conf);
  83 static int def_destroy(CONF *conf);
  84 static int def_destroy_data(CONF *conf);
  85 static int def_load(CONF *conf, const char *name, long *eline);
  86 static int def_load_bio(CONF *conf, BIO *bp, long *eline);
  87 static int def_dump(const CONF *conf, BIO *bp);
  88 static int def_is_number(const CONF *conf, char c);
  89 static int def_to_int(const CONF *conf, char c);
  90
  91 const char CONF_def_version[] = "CONF_def" OPENSSL_VERSION_PTEXT;
  92
  93 static CONF_METHOD default_method = {
  94     "OpenSSL default",
  95     def_create,
  96     def_init_default,
  97     def_destroy,
  98     def_destroy_data,
  99     def_load_bio,
 100     def_dump,
 101     def_is_number,
 102     def_to_int,
 103     def_load
 104 };
 105
 106 static CONF_METHOD WIN32_method = {
 107     "WIN32",
 108     def_create,
 109     def_init_WIN32,
 110     def_destroy,
 111     def_destroy_data,
 112     def_load_bio,
 113     def_dump,
 114     def_is_number,
 115     def_to_int,
 116     def_load
 117 };
 118
 119 CONF_METHOD *NCONF_default()
 120 {
 121     return &default_method;
 122 }
 123
 124 CONF_METHOD *NCONF_WIN32()
 125 {
 126     return &WIN32_method;
 127 }
 128
 129 static CONF *def_create(CONF_METHOD *meth)
 130 {
 131     CONF *ret;
 132
 133     ret = OPENSSL_malloc(sizeof(CONF) + sizeof(unsigned short *));
 134     if (ret)
 135         if (meth->init(ret) == 0) {
 136             OPENSSL_free(ret);
 137             ret = NULL;
 138         }
 139     return ret;
 140 }
 141
 142 static int def_init_default(CONF *conf)
 143 {
 144     if (conf == NULL)
 145         return 0;
 146
 147     conf->meth = &default_method;
 148     conf->meth_data = (void *)CONF_type_default;
 149     conf->data = NULL;
 150
 151     return 1;
 152 }
 153
 154 static int def_init_WIN32(CONF *conf)
 155 {
 156     if (conf == NULL)
 157         return 0;
 158
 159     conf->meth = &WIN32_method;
 160     conf->meth_data = (void *)CONF_type_win32;
 161     conf->data = NULL;
 162
 163     return 1;
 164 }
 165
 166 static int def_destroy(CONF *conf)
 167 {
 168     if (def_destroy_data(conf)) {
 169         OPENSSL_free(conf);
 170         return 1;
 171     }
 172     return 0;
 173 }
 174
 175 static int def_destroy_data(CONF *conf)
 176 {
 177     if (conf == NULL)
 178         return 0;
 179     _CONF_free_data(conf);
 180     return 1;
 181 }
 182
 183 static int def_load(CONF *conf, const char *name, long *line)
 184 {
 185     int ret;
 186     BIO *in = NULL;
 187
 188 #ifdef OPENSSL_SYS_VMS
 189     in = BIO_new_file(name, "r");
 190 #else
 191     in = BIO_new_file(name, "rb");
 192 #endif
 193     if (in == NULL) {
 194         if (ERR_GET_REASON(ERR_peek_last_error()) == BIO_R_NO_SUCH_FILE)
 195             CONFerr(CONF_F_DEF_LOAD, CONF_R_NO_SUCH_FILE);
 196         else
 197             CONFerr(CONF_F_DEF_LOAD, ERR_R_SYS_LIB);
 198         return 0;
 199     }
 200
 201     ret = def_load_bio(conf, in, line);
 202     BIO_free(in);
 203
 204     return ret;
 205 }
 206
 207 static int def_load_bio(CONF *conf, BIO *in, long *line)
 208 {
 209 /* The macro BUFSIZE conflicts with a system macro in VxWorks */
 210 #define CONFBUFSIZE     512
 211     int bufnum = 0, i, ii;
 212     BUF_MEM *buff = NULL;
 213     char *s, *p, *end;
 214     int again;
 215     long eline = 0;
 216     char btmp[DECIMAL_SIZE(eline) + 1];
 217     CONF_VALUE *v = NULL, *tv;
 218     CONF_VALUE *sv = NULL;
 219     char *section = NULL, *buf;
 220     char *start, *psection, *pname;
 221     void *h = (void *)(conf->data);
 222
 223     if ((buff = BUF_MEM_new()) == NULL) {
 224         CONFerr(CONF_F_DEF_LOAD_BIO, ERR_R_BUF_LIB);
 225         goto err;
 226     }
 227
 228     section = (char *)OPENSSL_malloc(10);
 229     if (section == NULL) {
 230         CONFerr(CONF_F_DEF_LOAD_BIO, ERR_R_MALLOC_FAILURE);
 231         goto err;
 232     }
 233     BUF_strlcpy(section, "default", 10);
 234
 235     if (_CONF_new_data(conf) == 0) {
 236         CONFerr(CONF_F_DEF_LOAD_BIO, ERR_R_MALLOC_FAILURE);
 237         goto err;
 238     }
 239
 240     sv = _CONF_new_section(conf, section);
 241     if (sv == NULL) {
 242         CONFerr(CONF_F_DEF_LOAD_BIO, CONF_R_UNABLE_TO_CREATE_NEW_SECTION);
 243         goto err;
 244     }
 245
 246     bufnum = 0;
 247     again = 0;
 248     for (;;) {
 249         if (!BUF_MEM_grow(buff, bufnum + CONFBUFSIZE)) {
 250             CONFerr(CONF_F_DEF_LOAD_BIO, ERR_R_BUF_LIB);
 251             goto err;
 252         }
 253         p = &(buff->data[bufnum]);
 254         *p = '\0';
 255         BIO_gets(in, p, CONFBUFSIZE - 1);
 256         p[CONFBUFSIZE - 1] = '\0';
 257         ii = i = strlen(p);
 258         if (i == 0 && !again)
 259             break;
 260         again = 0;
 261         while (i > 0) {
 262             if ((p[i - 1] != '\r') && (p[i - 1] != '\n'))
 263                 break;
 264             else
 265                 i--;
 266         }
 267         /*
 268          * we removed some trailing stuff so there is a new line on the end.
 269          */
 270         if (ii && i == ii)
 271             again = 1;          /* long line */
 272         else {
 273             p[i] = '\0';
 274             eline++;            /* another input line */
 275         }
 276
 277         /* we now have a line with trailing \r\n removed */
 278
 279         /* i is the number of bytes */
 280         bufnum += i;
 281
 282         v = NULL;
 283         /* check for line continuation */
 284         if (bufnum >= 1) {
 285             /*
 286              * If we have bytes and the last char '\\' and second last char
 287              * is not '\\'
 288              */
 289             p = &(buff->data[bufnum - 1]);
 290             if (IS_ESC(conf, p[0]) && ((bufnum <= 1) || !IS_ESC(conf, p[-1]))) {
 291                 bufnum--;
 292                 again = 1;
 293             }
 294         }
 295         if (again)
 296             continue;
 297         bufnum = 0;
 298         buf = buff->data;
 299
 300         clear_comments(conf, buf);
 301         s = eat_ws(conf, buf);
 302         if (IS_EOF(conf, *s))
 303             continue;           /* blank line */
 304         if (*s == '[') {
 305             char *ss;
 306
 307             s++;
 308             start = eat_ws(conf, s);
 309             ss = start;
 310  again:
 311             end = eat_alpha_numeric(conf, ss);
 312             p = eat_ws(conf, end);
 313             if (*p != ']') {
 314                 if (*p != '\0' && ss != p) {
 315                     ss = p;
 316                     goto again;
 317                 }
 318                 CONFerr(CONF_F_DEF_LOAD_BIO,
 319                         CONF_R_MISSING_CLOSE_SQUARE_BRACKET);
 320                 goto err;
 321             }
 322             *end = '\0';
 323             if (!str_copy(conf, NULL, &section, start))
 324                 goto err;
 325             if ((sv = _CONF_get_section(conf, section)) == NULL)
 326                 sv = _CONF_new_section(conf, section);
 327             if (sv == NULL) {
 328                 CONFerr(CONF_F_DEF_LOAD_BIO,
 329                         CONF_R_UNABLE_TO_CREATE_NEW_SECTION);
 330                 goto err;
 331             }
 332             continue;
 333         } else {
 334             pname = s;
 335             psection = NULL;
 336             end = eat_alpha_numeric(conf, s);
 337             if ((end[0] == ':') && (end[1] == ':')) {
 338                 *end = '\0';
 339                 end += 2;
 340                 psection = pname;
 341                 pname = end;
 342                 end = eat_alpha_numeric(conf, end);
 343             }
 344             p = eat_ws(conf, end);
 345             if (*p != '=') {
 346                 CONFerr(CONF_F_DEF_LOAD_BIO, CONF_R_MISSING_EQUAL_SIGN);
 347                 goto err;
 348             }
 349             *end = '\0';
 350             p++;
 351             start = eat_ws(conf, p);
 352             while (!IS_EOF(conf, *p))
 353                 p++;
 354             p--;
 355             while ((p != start) && (IS_WS(conf, *p)))
 356                 p--;
 357             p++;
 358             *p = '\0';
 359
 360             if (!(v = (CONF_VALUE *)OPENSSL_malloc(sizeof(CONF_VALUE)))) {
 361                 CONFerr(CONF_F_DEF_LOAD_BIO, ERR_R_MALLOC_FAILURE);
 362                 goto err;
 363             }
 364             if (psection == NULL)
 365                 psection = section;
 366             v->name = (char *)OPENSSL_malloc(strlen(pname) + 1);
 367             v->value = NULL;
 368             if (v->name == NULL) {
 369                 CONFerr(CONF_F_DEF_LOAD_BIO, ERR_R_MALLOC_FAILURE);
 370                 goto err;
 371             }
 372             BUF_strlcpy(v->name, pname, strlen(pname) + 1);
 373             if (!str_copy(conf, psection, &(v->value), start))
 374                 goto err;
 375
 376             if (strcmp(psection, section) != 0) {
 377                 if ((tv = _CONF_get_section(conf, psection))
 378                     == NULL)
 379                     tv = _CONF_new_section(conf, psection);
 380                 if (tv == NULL) {
 381                     CONFerr(CONF_F_DEF_LOAD_BIO,
 382                             CONF_R_UNABLE_TO_CREATE_NEW_SECTION);
 383                     goto err;
 384                 }
 385             } else
 386                 tv = sv;
 387 #if 1
 388             if (_CONF_add_string(conf, tv, v) == 0) {
 389                 CONFerr(CONF_F_DEF_LOAD_BIO, ERR_R_MALLOC_FAILURE);
 390                 goto err;
 391             }
 392 #else
 393             v->section = tv->section;
 394             if (!sk_CONF_VALUE_push(ts, v)) {
 395                 CONFerr(CONF_F_DEF_LOAD_BIO, ERR_R_MALLOC_FAILURE);
 396                 goto err;
 397             }
 398             vv = (CONF_VALUE *)lh_insert(conf->data, v);
 399             if (vv != NULL) {
 400                 sk_CONF_VALUE_delete_ptr(ts, vv);
 401                 OPENSSL_free(vv->name);
 402                 OPENSSL_free(vv->value);
 403                 OPENSSL_free(vv);
 404             }
 405 #endif
 406             v = NULL;
 407         }
 408     }
 409     if (buff != NULL)
 410         BUF_MEM_free(buff);
 411     if (section != NULL)
 412         OPENSSL_free(section);
 413     return (1);
 414  err:
 415     if (buff != NULL)
 416         BUF_MEM_free(buff);
 417     if (section != NULL)
 418         OPENSSL_free(section);
 419     if (line != NULL)
 420         *line = eline;
 421     BIO_snprintf(btmp, sizeof btmp, "%ld", eline);
 422     ERR_add_error_data(2, "line ", btmp);
 423     if ((h != conf->data) && (conf->data != NULL)) {
 424         CONF_free(conf->data);
 425         conf->data = NULL;
 426     }
 427     if (v != NULL) {
 428         if (v->name != NULL)
 429             OPENSSL_free(v->name);
 430         if (v->value != NULL)
 431             OPENSSL_free(v->value);
 432         if (v != NULL)
 433             OPENSSL_free(v);
 434     }
 435     return (0);
 436 }
 437
 438 static void clear_comments(CONF *conf, char *p)
 439 {
 440     for (;;) {
 441         if (IS_FCOMMENT(conf, *p)) {
 442             *p = '\0';
 443             return;
 444         }
 445         if (!IS_WS(conf, *p)) {
 446             break;
 447         }
 448         p++;
 449     }
 450
 451     for (;;) {
 452         if (IS_COMMENT(conf, *p)) {
 453             *p = '\0';
 454             return;
 455         }
 456         if (IS_DQUOTE(conf, *p)) {
 457             p = scan_dquote(conf, p);
 458             continue;
 459         }
 460         if (IS_QUOTE(conf, *p)) {
 461             p = scan_quote(conf, p);
 462             continue;
 463         }
 464         if (IS_ESC(conf, *p)) {
 465             p = scan_esc(conf, p);
 466             continue;
 467         }
 468         if (IS_EOF(conf, *p))
 469             return;
 470         else
 471             p++;
 472     }
 473 }
 474
 475 static int str_copy(CONF *conf, char *section, char **pto, char *from)
 476 {
 477     int q, r, rr = 0, to = 0, len = 0;
 478     char *s, *e, *rp, *p, *rrp, *np, *cp, v;
 479     BUF_MEM *buf;
 480
 481     if ((buf = BUF_MEM_new()) == NULL)
 482         return (0);
 483
 484     len = strlen(from) + 1;
 485     if (!BUF_MEM_grow(buf, len))
 486         goto err;
 487
 488     for (;;) {
 489         if (IS_QUOTE(conf, *from)) {
 490             q = *from;
 491             from++;
 492             while (!IS_EOF(conf, *from) && (*from != q)) {
 493                 if (IS_ESC(conf, *from)) {
 494                     from++;
 495                     if (IS_EOF(conf, *from))
 496                         break;
 497                 }
 498                 buf->data[to++] = *(from++);
 499             }
 500             if (*from == q)
 501                 from++;
 502         } else if (IS_DQUOTE(conf, *from)) {
 503             q = *from;
 504             from++;
 505             while (!IS_EOF(conf, *from)) {
 506                 if (*from == q) {
 507                     if (*(from + 1) == q) {
 508                         from++;
 509                     } else {
 510                         break;
 511                     }
 512                 }
 513                 buf->data[to++] = *(from++);
 514             }
 515             if (*from == q)
 516                 from++;
 517         } else if (IS_ESC(conf, *from)) {
 518             from++;
 519             v = *(from++);
 520             if (IS_EOF(conf, v))
 521                 break;
 522             else if (v == 'r')
 523                 v = '\r';
 524             else if (v == 'n')
 525                 v = '\n';
 526             else if (v == 'b')
 527                 v = '\b';
 528             else if (v == 't')
 529                 v = '\t';
 530             buf->data[to++] = v;
 531         } else if (IS_EOF(conf, *from))
 532             break;
 533         else if (*from == '$') {
 534             /* try to expand it */
 535             rrp = NULL;
 536             s = &(from[1]);
 537             if (*s == '{')
 538                 q = '}';
 539             else if (*s == '(')
 540                 q = ')';
 541             else
 542                 q = 0;
 543
 544             if (q)
 545                 s++;
 546             cp = section;
 547             e = np = s;
 548             while (IS_ALPHA_NUMERIC(conf, *e))
 549                 e++;
 550             if ((e[0] == ':') && (e[1] == ':')) {
 551                 cp = np;
 552                 rrp = e;
 553                 rr = *e;
 554                 *rrp = '\0';
 555                 e += 2;
 556                 np = e;
 557                 while (IS_ALPHA_NUMERIC(conf, *e))
 558                     e++;
 559             }
 560             r = *e;
 561             *e = '\0';
 562             rp = e;
 563             if (q) {
 564                 if (r != q) {
 565                     CONFerr(CONF_F_STR_COPY, CONF_R_NO_CLOSE_BRACE);
 566                     goto err;
 567                 }
 568                 e++;
 569             }
 570             /*-
 571              * So at this point we have
 572              * np which is the start of the name string which is
 573              *   '\0' terminated.
 574              * cp which is the start of the section string which is
 575              *   '\0' terminated.
 576              * e is the 'next point after'.
 577              * r and rr are the chars replaced by the '\0'
 578              * rp and rrp is where 'r' and 'rr' came from.
 579              */
 580             p = _CONF_get_string(conf, cp, np);
 581             if (rrp != NULL)
 582                 *rrp = rr;
 583             *rp = r;
 584             if (p == NULL) {
 585                 CONFerr(CONF_F_STR_COPY, CONF_R_VARIABLE_HAS_NO_VALUE);
 586                 goto err;
 587             }
 588             BUF_MEM_grow_clean(buf, (strlen(p) + buf->length - (e - from)));
 589             while (*p)
 590                 buf->data[to++] = *(p++);
 591
 592             /*
 593              * Since we change the pointer 'from', we also have to change the
 594              * perceived length of the string it points at.  /RL
 595              */
 596             len -= e - from;
 597             from = e;
 598
 599             /*
 600              * In case there were no braces or parenthesis around the
 601              * variable reference, we have to put back the character that was
 602              * replaced with a '\0'.  /RL
 603              */
 604             *rp = r;
 605         } else
 606             buf->data[to++] = *(from++);
 607     }
 608     buf->data[to] = '\0';
 609     if (*pto != NULL)
 610         OPENSSL_free(*pto);
 611     *pto = buf->data;
 612     OPENSSL_free(buf);
 613     return (1);
 614  err:
 615     if (buf != NULL)
 616         BUF_MEM_free(buf);
 617     return (0);
 618 }
 619
 620 static char *eat_ws(CONF *conf, char *p)
 621 {
 622     while (IS_WS(conf, *p) && (!IS_EOF(conf, *p)))
 623         p++;
 624     return (p);
 625 }
 626
 627 static char *eat_alpha_numeric(CONF *conf, char *p)
 628 {
 629     for (;;) {
 630         if (IS_ESC(conf, *p)) {
 631             p = scan_esc(conf, p);
 632             continue;
 633         }
 634         if (!IS_ALPHA_NUMERIC_PUNCT(conf, *p))
 635             return (p);
 636         p++;
 637     }
 638 }
 639
 640 static char *scan_quote(CONF *conf, char *p)
 641 {
 642     int q = *p;
 643
 644     p++;
 645     while (!(IS_EOF(conf, *p)) && (*p != q)) {
 646         if (IS_ESC(conf, *p)) {
 647             p++;
 648             if (IS_EOF(conf, *p))
 649                 return (p);
 650         }
 651         p++;
 652     }
 653     if (*p == q)
 654         p++;
 655     return (p);
 656 }
 657
 658 static char *scan_dquote(CONF *conf, char *p)
 659 {
 660     int q = *p;
 661
 662     p++;
 663     while (!(IS_EOF(conf, *p))) {
 664         if (*p == q) {
 665             if (*(p + 1) == q) {
 666                 p++;
 667             } else {
 668                 break;
 669             }
 670         }
 671         p++;
 672     }
 673     if (*p == q)
 674         p++;
 675     return (p);
 676 }
 677
 678 static void dump_value_doall_arg(CONF_VALUE *a, BIO *out)
 679 {
 680     if (a->name)
 681         BIO_printf(out, "[%s] %s=%s\n", a->section, a->name, a->value);
 682     else
 683         BIO_printf(out, "[[%s]]\n", a->section);
 684 }
 685
 686 static IMPLEMENT_LHASH_DOALL_ARG_FN(dump_value, CONF_VALUE, BIO)
 687
 688 static int def_dump(const CONF *conf, BIO *out)
 689 {
 690     lh_CONF_VALUE_doall_arg(conf->data, LHASH_DOALL_ARG_FN(dump_value),
 691                             BIO, out);
 692     return 1;
 693 }
 694
 695 static int def_is_number(const CONF *conf, char c)
 696 {
 697     return IS_NUMBER(conf, c);
 698 }
 699
 700 static int def_to_int(const CONF *conf, char c)
 701 {
 702     return c - '0';
 703 }