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gnum4.c revision 1.1 
      1 /*	$NetBSD: gnum4.c,v 1.1 2001/11/14 06:16:08 tv Exp $	*/
      2 /* $OpenBSD: gnum4.c,v 1.15 2001/10/13 20:18:48 espie Exp $ */
      3 
      4 /*
      5  * Copyright (c) 1999 Marc Espie
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 /*
     30  * functions needed to support gnu-m4 extensions, including a fake freezing
     31  */
     32 
     33 #include <sys/param.h>
     34 #include <sys/types.h>
     35 #include <sys/wait.h>
     36 #include <ctype.h>
     37 #include <err.h>
     38 #include <errno.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 "mdef.h"
     46 #include "stdd.h"
     47 #include "extern.h"
     48 
     49 
     50 int mimic_gnu = 0;
     51 
     52 /*
     53  * Support for include path search
     54  * First search in the the current directory.
     55  * If not found, and the path is not absolute, include path kicks in.
     56  * First, -I options, in the order found on the command line.
     57  * Then M4PATH env variable
     58  */
     59 
     60 struct path_entry {
     61 	char *name;
     62 	struct path_entry *next;
     63 } *first, *last;
     64 
     65 static struct path_entry *new_path_entry __P((const char *));
     66 static void ensure_m4path __P((void));
     67 static struct input_file *dopath __P((struct input_file *, const char *));
     68 
     69 static struct path_entry *
     70 new_path_entry(dirname)
     71 	const char *dirname;
     72 {
     73 	struct path_entry *n;
     74 
     75 	n = malloc(sizeof(struct path_entry));
     76 	if (!n)
     77 		errx(1, "out of memory");
     78 	n->name = strdup(dirname);
     79 	if (!n->name)
     80 		errx(1, "out of memory");
     81 	n->next = 0;
     82 	return n;
     83 }
     84 
     85 void
     86 addtoincludepath(dirname)
     87 	const char *dirname;
     88 {
     89 	struct path_entry *n;
     90 
     91 	n = new_path_entry(dirname);
     92 
     93 	if (last) {
     94 		last->next = n;
     95 		last = n;
     96 	}
     97 	else
     98 		last = first = n;
     99 }
    100 
    101 static void
    102 ensure_m4path()
    103 {
    104 	static int envpathdone = 0;
    105 	char *envpath;
    106 	char *sweep;
    107 	char *path;
    108 
    109 	if (envpathdone)
    110 		return;
    111 	envpathdone = TRUE;
    112 	envpath = getenv("M4PATH");
    113 	if (!envpath)
    114 		return;
    115 	/* for portability: getenv result is read-only */
    116 	envpath = strdup(envpath);
    117 	if (!envpath)
    118 		errx(1, "out of memory");
    119 	for (sweep = envpath;
    120 	    (path = strsep(&sweep, ":")) != NULL;)
    121 	    addtoincludepath(path);
    122 	free(envpath);
    123 }
    124 
    125 static
    126 struct input_file *
    127 dopath(i, filename)
    128 	struct input_file *i;
    129 	const char *filename;
    130 {
    131 	char path[MAXPATHLEN];
    132 	struct path_entry *pe;
    133 	FILE *f;
    134 
    135 	for (pe = first; pe; pe = pe->next) {
    136 		snprintf(path, sizeof(path), "%s/%s", pe->name, filename);
    137 		if ((f = fopen(path, "r")) != 0) {
    138 			set_input(i, f, path);
    139 			return i;
    140 		}
    141 	}
    142 	return NULL;
    143 }
    144 
    145 struct input_file *
    146 fopen_trypath(i, filename)
    147 	struct input_file *i;
    148 	const char *filename;
    149 {
    150 	FILE *f;
    151 
    152 	f = fopen(filename, "r");
    153 	if (f != NULL) {
    154 		set_input(i, f, filename);
    155 		return i;
    156 	}
    157 	if (filename[0] == '/')
    158 		return NULL;
    159 
    160 	ensure_m4path();
    161 
    162 	return dopath(i, filename);
    163 }
    164 
    165 void
    166 doindir(argv, argc)
    167 	const char *argv[];
    168 	int argc;
    169 {
    170 	ndptr p;
    171 
    172 	p = lookup(argv[2]);
    173 	if (p == NULL)
    174 		errx(1, "undefined macro %s", argv[2]);
    175 	argv[1] = p->defn;
    176 	eval(argv+1, argc-1, p->type);
    177 }
    178 
    179 void
    180 dobuiltin(argv, argc)
    181 	const char *argv[];
    182 	int argc;
    183 {
    184 	int n;
    185 	argv[1] = NULL;
    186 	n = builtin_type(argv[2]);
    187 	if (n != -1)
    188 		eval(argv+1, argc-1, n);
    189 	else
    190 		errx(1, "unknown builtin %s", argv[2]);
    191 }
    192 
    193 
    194 /* We need some temporary buffer space, as pb pushes BACK and substitution
    195  * proceeds forward... */
    196 static char *buffer;
    197 static size_t bufsize = 0;
    198 static size_t current = 0;
    199 
    200 static void addchars __P((const char *, size_t));
    201 static void addchar __P((char));
    202 static char *twiddle __P((const char *));
    203 static char *getstring __P((void));
    204 static void exit_regerror __P((int, regex_t *));
    205 static void do_subst __P((const char *, regex_t *, const char *, regmatch_t *));
    206 static void do_regexpindex __P((const char *, regex_t *, regmatch_t *));
    207 static void do_regexp __P((const char *, regex_t *, const char *, regmatch_t *));
    208 static void add_sub __P((int, const char *, regex_t *, regmatch_t *));
    209 static void add_replace __P((const char *, regex_t *, const char *, regmatch_t *));
    210 #define addconstantstring(s) addchars((s), sizeof(s)-1)
    211 
    212 static void
    213 addchars(c, n)
    214 	const char *c;
    215 	size_t n;
    216 {
    217 	if (n == 0)
    218 		return;
    219 	while (current + n > bufsize) {
    220 		if (bufsize == 0)
    221 			bufsize = 1024;
    222 		else
    223 			bufsize *= 2;
    224 		buffer = realloc(buffer, bufsize);
    225 		if (buffer == NULL)
    226 			errx(1, "out of memory");
    227 	}
    228 	memcpy(buffer+current, c, n);
    229 	current += n;
    230 }
    231 
    232 static void
    233 addchar(c)
    234 	char c;
    235 {
    236 	if (current +1 > bufsize) {
    237 		if (bufsize == 0)
    238 			bufsize = 1024;
    239 		else
    240 			bufsize *= 2;
    241 		buffer = realloc(buffer, bufsize);
    242 		if (buffer == NULL)
    243 			errx(1, "out of memory");
    244 	}
    245 	buffer[current++] = c;
    246 }
    247 
    248 static char *
    249 getstring()
    250 {
    251 	addchar('\0');
    252 	current = 0;
    253 	return buffer;
    254 }
    255 
    256 
    257 static void
    258 exit_regerror(er, re)
    259 	int er;
    260 	regex_t *re;
    261 {
    262 	size_t 	errlen;
    263 	char 	*errbuf;
    264 
    265 	errlen = regerror(er, re, NULL, 0);
    266 	errbuf = xalloc(errlen);
    267 	regerror(er, re, errbuf, errlen);
    268 	errx(1, "regular expression error: %s", errbuf);
    269 }
    270 
    271 static void
    272 add_sub(n, string, re, pm)
    273 	int n;
    274 	const char *string;
    275 	regex_t *re;
    276 	regmatch_t *pm;
    277 {
    278 	if (n > re->re_nsub)
    279 		warnx("No subexpression %d", n);
    280 	/* Subexpressions that did not match are
    281 	 * not an error.  */
    282 	else if (pm[n].rm_so != -1 &&
    283 	    pm[n].rm_eo != -1) {
    284 		addchars(string + pm[n].rm_so,
    285 			pm[n].rm_eo - pm[n].rm_so);
    286 	}
    287 }
    288 
    289 /* Add replacement string to the output buffer, recognizing special
    290  * constructs and replacing them with substrings of the original string.
    291  */
    292 static void
    293 add_replace(string, re, replace, pm)
    294 	const char *string;
    295 	regex_t *re;
    296 	const char *replace;
    297 	regmatch_t *pm;
    298 {
    299 	const char *p;
    300 
    301 	for (p = replace; *p != '\0'; p++) {
    302 		if (*p == '&' && !mimic_gnu) {
    303 			add_sub(0, string, re, pm);
    304 			continue;
    305 		}
    306 		if (*p == '\\') {
    307 			if (p[1] == '\\') {
    308 				addchar(p[1]);
    309 				p++;
    310 				continue;
    311 			}
    312 			if (p[1] == '&') {
    313 				if (mimic_gnu)
    314 					add_sub(0, string, re, pm);
    315 				else
    316 					addchar(p[1]);
    317 				p++;
    318 				continue;
    319 			}
    320 			if (isdigit(p[1])) {
    321 				add_sub(*(++p) - '0', string, re, pm);
    322 				continue;
    323 			}
    324 		}
    325 	    	addchar(*p);
    326 	}
    327 }
    328 
    329 static void
    330 do_subst(string, re, replace, pm)
    331 	const char *string;
    332 	regex_t *re;
    333 	const char *replace;
    334 	regmatch_t *pm;
    335 {
    336 	int error;
    337 	int flags = 0;
    338 	const char *last_match = NULL;
    339 
    340 	while ((error = regexec(re, string, re->re_nsub+1, pm, flags)) == 0) {
    341 		if (pm[0].rm_eo != 0) {
    342 			if (string[pm[0].rm_eo-1] == '\n')
    343 				flags = 0;
    344 			else
    345 				flags = REG_NOTBOL;
    346 		}
    347 
    348 		/* NULL length matches are special... We use the `vi-mode'
    349 		 * rule: don't allow a NULL-match at the last match
    350 		 * position.
    351 		 */
    352 		if (pm[0].rm_so == pm[0].rm_eo &&
    353 		    string + pm[0].rm_so == last_match) {
    354 			if (*string == '\0')
    355 				return;
    356 			addchar(*string);
    357 			if (*string++ == '\n')
    358 				flags = 0;
    359 			else
    360 				flags = REG_NOTBOL;
    361 			continue;
    362 		}
    363 		last_match = string + pm[0].rm_so;
    364 		addchars(string, pm[0].rm_so);
    365 		add_replace(string, re, replace, pm);
    366 		string += pm[0].rm_eo;
    367 	}
    368 	if (error != REG_NOMATCH)
    369 		exit_regerror(error, re);
    370 	pbstr(string);
    371 }
    372 
    373 static void
    374 do_regexp(string, re, replace, pm)
    375 	const char *string;
    376 	regex_t *re;
    377 	const char *replace;
    378 	regmatch_t *pm;
    379 {
    380 	int error;
    381 
    382 	switch(error = regexec(re, string, re->re_nsub+1, pm, 0)) {
    383 	case 0:
    384 		add_replace(string, re, replace, pm);
    385 		pbstr(getstring());
    386 		break;
    387 	case REG_NOMATCH:
    388 		break;
    389 	default:
    390 		exit_regerror(error, re);
    391 	}
    392 }
    393 
    394 static void
    395 do_regexpindex(string, re, pm)
    396 	const char *string;
    397 	regex_t *re;
    398 	regmatch_t *pm;
    399 {
    400 	int error;
    401 
    402 	switch(error = regexec(re, string, re->re_nsub+1, pm, 0)) {
    403 	case 0:
    404 		pbunsigned(pm[0].rm_so);
    405 		break;
    406 	case REG_NOMATCH:
    407 		pbnum(-1);
    408 		break;
    409 	default:
    410 		exit_regerror(error, re);
    411 	}
    412 }
    413 
    414 /* In Gnu m4 mode, parentheses for backmatch don't work like POSIX 1003.2
    415  * says. So we twiddle with the regexp before passing it to regcomp.
    416  */
    417 static char *
    418 twiddle(p)
    419 	const char *p;
    420 {
    421 	/* This could use strcspn for speed... */
    422 	while (*p != '\0') {
    423 		if (*p == '\\') {
    424 			switch(p[1]) {
    425 			case '(':
    426 			case ')':
    427 			case '|':
    428 				addchar(p[1]);
    429 				break;
    430 			case 'w':
    431 				addconstantstring("[_a-zA-Z0-9]");
    432 				break;
    433 			case 'W':
    434 				addconstantstring("[^_a-zA-Z0-9]");
    435 				break;
    436 			case '<':
    437 				addconstantstring("[[:<:]]");
    438 				break;
    439 			case '>':
    440 				addconstantstring("[[:>:]]");
    441 				break;
    442 			default:
    443 				addchars(p, 2);
    444 				break;
    445 			}
    446 			p+=2;
    447 			continue;
    448 		}
    449 		if (*p == '(' || *p == ')' || *p == '|')
    450 			addchar('\\');
    451 
    452 		addchar(*p);
    453 		p++;
    454 	}
    455 	return getstring();
    456 }
    457 
    458 /* patsubst(string, regexp, opt replacement) */
    459 /* argv[2]: string
    460  * argv[3]: regexp
    461  * argv[4]: opt rep
    462  */
    463 void
    464 dopatsubst(argv, argc)
    465 	const char *argv[];
    466 	int argc;
    467 {
    468 	int error;
    469 	regex_t re;
    470 	regmatch_t *pmatch;
    471 
    472 	if (argc <= 3) {
    473 		warnx("Too few arguments to patsubst");
    474 		return;
    475 	}
    476 	error = regcomp(&re, mimic_gnu ? twiddle(argv[3]) : argv[3],
    477 	    REG_NEWLINE | REG_EXTENDED);
    478 	if (error != 0)
    479 		exit_regerror(error, &re);
    480 
    481 	pmatch = xalloc(sizeof(regmatch_t) * (re.re_nsub+1));
    482 	do_subst(argv[2], &re,
    483 	    argc != 4 && argv[4] != NULL ? argv[4] : "", pmatch);
    484 	pbstr(getstring());
    485 	free(pmatch);
    486 	regfree(&re);
    487 }
    488 
    489 void
    490 doregexp(argv, argc)
    491 	const char *argv[];
    492 	int argc;
    493 {
    494 	int error;
    495 	regex_t re;
    496 	regmatch_t *pmatch;
    497 
    498 	if (argc <= 3) {
    499 		warnx("Too few arguments to regexp");
    500 		return;
    501 	}
    502 	error = regcomp(&re, mimic_gnu ? twiddle(argv[3]) : argv[3],
    503 	    REG_EXTENDED);
    504 	if (error != 0)
    505 		exit_regerror(error, &re);
    506 
    507 	pmatch = xalloc(sizeof(regmatch_t) * (re.re_nsub+1));
    508 	if (argv[4] == NULL || argc == 4)
    509 		do_regexpindex(argv[2], &re, pmatch);
    510 	else
    511 		do_regexp(argv[2], &re, argv[4], pmatch);
    512 	free(pmatch);
    513 	regfree(&re);
    514 }
    515 
    516 void
    517 doesyscmd(cmd)
    518 	const char *cmd;
    519 {
    520 	int p[2];
    521 	pid_t pid, cpid;
    522 	char *argv[4];
    523 	int cc;
    524 	int status;
    525 
    526 	/* Follow gnu m4 documentation: first flush buffers. */
    527 	fflush(NULL);
    528 
    529 	argv[0] = "sh";
    530 	argv[1] = "-c";
    531 	argv[2] = (char *)cmd;
    532 	argv[3] = NULL;
    533 
    534 	/* Just set up standard output, share stderr and stdin with m4 */
    535 	if (pipe(p) == -1)
    536 		err(1, "bad pipe");
    537 	switch(cpid = fork()) {
    538 	case -1:
    539 		err(1, "bad fork");
    540 		/* NOTREACHED */
    541 	case 0:
    542 		(void) close(p[0]);
    543 		(void) dup2(p[1], 1);
    544 		(void) close(p[1]);
    545 		execv(_PATH_BSHELL, argv);
    546 		exit(1);
    547 	default:
    548 		/* Read result in two stages, since m4's buffer is
    549 		 * pushback-only. */
    550 		(void) close(p[1]);
    551 		do {
    552 			char result[BUFSIZE];
    553 			cc = read(p[0], result, sizeof result);
    554 			if (cc > 0)
    555 				addchars(result, cc);
    556 		} while (cc > 0 || (cc == -1 && errno == EINTR));
    557 
    558 		(void) close(p[0]);
    559 		while ((pid = wait(&status)) != cpid && pid >= 0)
    560 			continue;
    561 		pbstr(getstring());
    562 	}
    563 }
    564