usr.bin/m4/gnum4.c

   1 /* $OpenBSD: gnum4.c,v 1.18 2002/04/26 16:15:16 espie Exp $ */
   2
   3 /*
   4  * Copyright (c) 1999 Marc Espie
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  *
  27  * $FreeBSD: src/usr.bin/m4/gnum4.c,v 1.9 2004/05/18 15:53:58 stefanf Exp $
  28  * $DragonFly: src/usr.bin/m4/gnum4.c,v 1.3 2006/12/27 21:29:02 pavalos Exp $
  29  */
  30
  31 /*
  32  * functions needed to support gnu-m4 extensions, including a fake freezing
  33  */
  34
  35 #include <sys/param.h>
  36 #include <sys/types.h>
  37 #include <sys/wait.h>
  38 #include <ctype.h>
  39 #include <paths.h>
  40 #include <regex.h>
  41 #include <stddef.h>
  42 #include <stdlib.h>
  43 #include <stdio.h>
  44 #include <string.h>
  45 #include <err.h>
  46 #include <errno.h>
  47 #include <unistd.h>
  48 #include "mdef.h"
  49 #include "stdd.h"
  50 #include "extern.h"
  51
  52
  53 int mimic_gnu = 0;
  54
  55 /*
  56  * Support for include path search
  57  * First search in the the current directory.
  58  * If not found, and the path is not absolute, include path kicks in.
  59  * First, -I options, in the order found on the command line.
  60  * Then M4PATH env variable
  61  */
  62
  63 struct path_entry {
  64         char *name;
  65         struct path_entry *next;
  66 } *first, *last;
  67
  68 static struct path_entry *new_path_entry(const char *);
  69 static void ensure_m4path(void);
  70 static struct input_file *dopath(struct input_file *, const char *);
  71
  72 static struct path_entry *
  73 new_path_entry(const char *dirname)
  74 {
  75         struct path_entry *n;
  76
  77         n = malloc(sizeof(struct path_entry));
  78         if (!n)
  79                 errx(1, "out of memory");
  80         n->name = strdup(dirname);
  81         if (!n->name)
  82                 errx(1, "out of memory");
  83         n->next = 0;
  84         return n;
  85 }
  86
  87 void
  88 addtoincludepath(const char *dirname)
  89 {
  90         struct path_entry *n;
  91
  92         n = new_path_entry(dirname);
  93
  94         if (last) {
  95                 last->next = n;
  96                 last = n;
  97         }
  98         else
  99                 last = first = n;
 100 }
 101
 102 static void
 103 ensure_m4path(void)
 104 {
 105         static int envpathdone = 0;
 106         char *envpath;
 107         char *sweep;
 108         char *path;
 109
 110         if (envpathdone)
 111                 return;
 112         envpathdone = TRUE;
 113         envpath = getenv("M4PATH");
 114         if (!envpath)
 115                 return;
 116         /* for portability: getenv result is read-only */
 117         envpath = strdup(envpath);
 118         if (!envpath)
 119                 errx(1, "out of memory");
 120         for (sweep = envpath;
 121             (path = strsep(&sweep, ":")) != NULL;)
 122             addtoincludepath(path);
 123         free(envpath);
 124 }
 125
 126 static
 127 struct input_file *
 128 dopath(struct input_file *i, const char *filename)
 129 {
 130         char path[MAXPATHLEN];
 131         struct path_entry *pe;
 132         FILE *f;
 133
 134         for (pe = first; pe; pe = pe->next) {
 135                 snprintf(path, sizeof(path), "%s/%s", pe->name, filename);
 136                 if ((f = fopen(path, "r")) != 0) {
 137                         set_input(i, f, path);
 138                         return i;
 139                 }
 140         }
 141         return NULL;
 142 }
 143
 144 struct input_file *
 145 fopen_trypath(struct input_file *i, const char *filename)
 146 {
 147         FILE *f;
 148
 149         f = fopen(filename, "r");
 150         if (f != NULL) {
 151                 set_input(i, f, filename);
 152                 return i;
 153         }
 154         if (filename[0] == '/')
 155                 return NULL;
 156
 157         ensure_m4path();
 158
 159         return dopath(i, filename);
 160 }
 161
 162 void
 163 doindir(const char *argv[], int argc)
 164 {
 165         ndptr p;
 166
 167         p = lookup(argv[2]);
 168         if (p == NULL)
 169                 errx(1, "undefined macro %s", argv[2]);
 170         argv[1] = p->defn;
 171         eval(argv+1, argc-1, p->type);
 172 }
 173
 174 void
 175 dobuiltin(const char *argv[], int argc)
 176 {
 177         int n;
 178         argv[1] = NULL;
 179         n = builtin_type(argv[2]);
 180         if (n != -1)
 181                 eval(argv+1, argc-1, n);
 182         else
 183                 errx(1, "unknown builtin %s", argv[2]);
 184 }
 185
 186
 187 /* We need some temporary buffer space, as pb pushes BACK and substitution
 188  * proceeds forward... */
 189 static char *buffer;
 190 static size_t bufsize = 0;
 191 static size_t current = 0;
 192
 193 static void addchars(const char *, size_t);
 194 static void addchar(int);
 195 static char *twiddle(const char *);
 196 static char *getstring(void);
 197 static void exit_regerror(int, regex_t *);
 198 static void do_subst(const char *, regex_t *, const char *, regmatch_t *);
 199 static void do_regexpindex(const char *, regex_t *, regmatch_t *);
 200 static void do_regexp(const char *, regex_t *, const char *, regmatch_t *);
 201 static void add_sub(size_t, const char *, regex_t *, regmatch_t *);
 202 static void add_replace(const char *, regex_t *, const char *, regmatch_t *);
 203 #define addconstantstring(s) addchars((s), sizeof(s)-1)
 204
 205 static void
 206 addchars(const char *c, size_t n)
 207 {
 208         if (n == 0)
 209                 return;
 210         while (current + n > bufsize) {
 211                 if (bufsize == 0)
 212                         bufsize = 1024;
 213                 else
 214                         bufsize *= 2;
 215                 buffer = realloc(buffer, bufsize);
 216                 if (buffer == NULL)
 217                         errx(1, "out of memory");
 218         }
 219         memcpy(buffer+current, c, n);
 220         current += n;
 221 }
 222
 223 static void
 224 addchar(int c)
 225 {
 226         if (current +1 > bufsize) {
 227                 if (bufsize == 0)
 228                         bufsize = 1024;
 229                 else
 230                         bufsize *= 2;
 231                 buffer = realloc(buffer, bufsize);
 232                 if (buffer == NULL)
 233                         errx(1, "out of memory");
 234         }
 235         buffer[current++] = c;
 236 }
 237
 238 static char *
 239 getstring(void)
 240 {
 241         addchar('\0');
 242         current = 0;
 243         return buffer;
 244 }
 245
 246
 247 static void
 248 exit_regerror(int er, regex_t *re)
 249 {
 250         size_t  errlen;
 251         char    *errbuf;
 252
 253         errlen = regerror(er, re, NULL, 0);
 254         errbuf = xalloc(errlen);
 255         regerror(er, re, errbuf, errlen);
 256         errx(1, "regular expression error: %s", errbuf);
 257 }
 258
 259 static void
 260 add_sub(size_t n, const char *string, regex_t *re, regmatch_t *pm)
 261 {
 262         if (n > re->re_nsub)
 263                 warnx("No subexpression %zu", n);
 264         /* Subexpressions that did not match are
 265          * not an error.  */
 266         else if (pm[n].rm_so != -1 &&
 267             pm[n].rm_eo != -1) {
 268                 addchars(string + pm[n].rm_so,
 269                         pm[n].rm_eo - pm[n].rm_so);
 270         }
 271 }
 272
 273 /* Add replacement string to the output buffer, recognizing special
 274  * constructs and replacing them with substrings of the original string.
 275  */
 276 static void
 277 add_replace(const char *string, regex_t *re, const char *replace, regmatch_t *pm)
 278 {
 279         const char *p;
 280
 281         for (p = replace; *p != '\0'; p++) {
 282                 if (*p == '&' && !mimic_gnu) {
 283                         add_sub(0, string, re, pm);
 284                         continue;
 285                 }
 286                 if (*p == '\\') {
 287                         if (p[1] == '\\') {
 288                                 addchar(p[1]);
 289                                 p++;
 290                                 continue;
 291                         }
 292                         if (p[1] == '&') {
 293                                 if (mimic_gnu)
 294                                         add_sub(0, string, re, pm);
 295                                 else
 296                                         addchar(p[1]);
 297                                 p++;
 298                                 continue;
 299                         }
 300                         if (isdigit(p[1])) {
 301                                 add_sub(*(++p) - '0', string, re, pm);
 302                                 continue;
 303                         }
 304                 }
 305                 addchar(*p);
 306         }
 307 }
 308
 309 static void
 310 do_subst(const char *string, regex_t *re, const char *replace, regmatch_t *pm)
 311 {
 312         int error;
 313         int flags = 0;
 314         const char *last_match = NULL;
 315
 316         while ((error = regexec(re, string, re->re_nsub+1, pm, flags)) == 0) {
 317                 if (pm[0].rm_eo != 0) {
 318                         if (string[pm[0].rm_eo-1] == '\n')
 319                                 flags = 0;
 320                         else
 321                                 flags = REG_NOTBOL;
 322                 }
 323
 324                 /* NULL length matches are special... We use the `vi-mode'
 325                  * rule: don't allow a NULL-match at the last match
 326                  * position.
 327                  */
 328                 if (pm[0].rm_so == pm[0].rm_eo &&
 329                     string + pm[0].rm_so == last_match) {
 330                         if (*string == '\0')
 331                                 return;
 332                         addchar(*string);
 333                         if (*string++ == '\n')
 334                                 flags = 0;
 335                         else
 336                                 flags = REG_NOTBOL;
 337                         continue;
 338                 }
 339                 last_match = string + pm[0].rm_so;
 340                 addchars(string, pm[0].rm_so);
 341                 add_replace(string, re, replace, pm);
 342                 string += pm[0].rm_eo;
 343         }
 344         if (error != REG_NOMATCH)
 345                 exit_regerror(error, re);
 346         pbstr(string);
 347 }
 348
 349 static void
 350 do_regexp(const char *string, regex_t *re, const char *replace, regmatch_t *pm)
 351 {
 352         int error;
 353
 354         switch(error = regexec(re, string, re->re_nsub+1, pm, 0)) {
 355         case 0:
 356                 add_replace(string, re, replace, pm);
 357                 pbstr(getstring());
 358                 break;
 359         case REG_NOMATCH:
 360                 break;
 361         default:
 362                 exit_regerror(error, re);
 363         }
 364 }
 365
 366 static void
 367 do_regexpindex(const char *string, regex_t *re, regmatch_t *pm)
 368 {
 369         int error;
 370
 371         switch(error = regexec(re, string, re->re_nsub+1, pm, 0)) {
 372         case 0:
 373                 pbunsigned(pm[0].rm_so);
 374                 break;
 375         case REG_NOMATCH:
 376                 pbnum(-1);
 377                 break;
 378         default:
 379                 exit_regerror(error, re);
 380         }
 381 }
 382
 383 /* In Gnu m4 mode, parentheses for backmatch don't work like POSIX 1003.2
 384  * says. So we twiddle with the regexp before passing it to regcomp.
 385  */
 386 static char *
 387 twiddle(const char *p)
 388 {
 389         /* This could use strcspn for speed... */
 390         while (*p != '\0') {
 391                 if (*p == '\\') {
 392                         switch(p[1]) {
 393                         case '(':
 394                         case ')':
 395                         case '|':
 396                                 addchar(p[1]);
 397                                 break;
 398                         case 'w':
 399                                 addconstantstring("[_a-zA-Z0-9]");
 400                                 break;
 401                         case 'W':
 402                                 addconstantstring("[^_a-zA-Z0-9]");
 403                                 break;
 404                         case '<':
 405                                 addconstantstring("[[:<:]]");
 406                                 break;
 407                         case '>':
 408                                 addconstantstring("[[:>:]]");
 409                                 break;
 410                         default:
 411                                 addchars(p, 2);
 412                                 break;
 413                         }
 414                         p+=2;
 415                         continue;
 416                 }
 417                 if (*p == '(' || *p == ')' || *p == '|')
 418                         addchar('\\');
 419
 420                 addchar(*p);
 421                 p++;
 422         }
 423         return getstring();
 424 }
 425
 426 /* patsubst(string, regexp, opt replacement) */
 427 /* argv[2]: string
 428  * argv[3]: regexp
 429  * argv[4]: opt rep
 430  */
 431 void
 432 dopatsubst(const char *argv[], int argc)
 433 {
 434         int error;
 435         regex_t re;
 436         regmatch_t *pmatch;
 437
 438         if (argc <= 3) {
 439                 warnx("Too few arguments to patsubst");
 440                 return;
 441         }
 442         error = regcomp(&re, mimic_gnu ? twiddle(argv[3]) : argv[3],
 443             REG_NEWLINE | REG_EXTENDED);
 444         if (error != 0)
 445                 exit_regerror(error, &re);
 446
 447         pmatch = xalloc(sizeof(regmatch_t) * (re.re_nsub+1));
 448         do_subst(argv[2], &re,
 449             argc != 4 && argv[4] != NULL ? argv[4] : "", pmatch);
 450         pbstr(getstring());
 451         free(pmatch);
 452         regfree(&re);
 453 }
 454
 455 void
 456 doregexp(const char *argv[], int argc)
 457 {
 458         int error;
 459         regex_t re;
 460         regmatch_t *pmatch;
 461
 462         if (argc <= 3) {
 463                 warnx("Too few arguments to regexp");
 464                 return;
 465         }
 466         error = regcomp(&re, mimic_gnu ? twiddle(argv[3]) : argv[3],
 467             REG_EXTENDED);
 468         if (error != 0)
 469                 exit_regerror(error, &re);
 470
 471         pmatch = xalloc(sizeof(regmatch_t) * (re.re_nsub+1));
 472         if (argv[4] == NULL || argc == 4)
 473                 do_regexpindex(argv[2], &re, pmatch);
 474         else
 475                 do_regexp(argv[2], &re, argv[4], pmatch);
 476         free(pmatch);
 477         regfree(&re);
 478 }
 479
 480 void
 481 doesyscmd(const char *cmd)
 482 {
 483         int p[2];
 484         pid_t pid, cpid;
 485         int cc;
 486         int status;
 487
 488         /* Follow gnu m4 documentation: first flush buffers. */
 489         fflush(NULL);
 490
 491         /* Just set up standard output, share stderr and stdin with m4 */
 492         if (pipe(p) == -1)
 493                 err(1, "bad pipe");
 494         switch(cpid = fork()) {
 495         case -1:
 496                 err(1, "bad fork");
 497                 /* NOTREACHED */
 498         case 0:
 499                 (void) close(p[0]);
 500                 (void) dup2(p[1], 1);
 501                 (void) close(p[1]);
 502                 execl(_PATH_BSHELL, "sh", "-c", cmd, NULL);
 503                 exit(1);
 504         default:
 505                 /* Read result in two stages, since m4's buffer is
 506                  * pushback-only. */
 507                 (void) close(p[1]);
 508                 do {
 509                         char result[BUFSIZE];
 510                         cc = read(p[0], result, sizeof result);
 511                         if (cc > 0)
 512                                 addchars(result, cc);
 513                 } while (cc > 0 || (cc == -1 && errno == EINTR));
 514
 515                 (void) close(p[0]);
 516                 while ((pid = wait(&status)) != cpid && pid >= 0)
 517                         continue;
 518                 pbstr(getstring());
 519         }
 520 }