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gnum4.c revision 1.3 
      1 /*	$NetBSD: gnum4.c,v 1.3 2004/04/23 02:58:29 simonb 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 <errno.h>
     38 #include <paths.h>
     39 #include <regex.h>
     40 #include <stddef.h>
     41 #include <stdlib.h>
     42 #include <stdio.h>
     43 #include <string.h>
     44 #include "mdef.h"
     45 #include "stdd.h"
     46 #include "extern.h"
     47 
     48 
     49 int mimic_gnu = 0;
     50 
     51 /*
     52  * Support for include path search
     53  * First search in the current directory.
     54  * If not found, and the path is not absolute, include path kicks in.
     55  * First, -I options, in the order found on the command line.
     56  * Then M4PATH env variable
     57  */
     58 
     59 struct path_entry {
     60 	char *name;
     61 	struct path_entry *next;
     62 } *first, *last;
     63 
     64 static struct path_entry *new_path_entry __P((const char *));
     65 static void ensure_m4path __P((void));
     66 static struct input_file *dopath __P((struct input_file *, const char *));
     67 
     68 static struct path_entry *
     69 new_path_entry(dirname)
     70 	const char *dirname;
     71 {
     72 	struct path_entry *n;
     73 
     74 	n = malloc(sizeof(struct path_entry));
     75 	if (!n)
     76 		errx(1, "out of memory");
     77 	n->name = strdup(dirname);
     78 	if (!n->name)
     79 		errx(1, "out of memory");
     80 	n->next = 0;
     81 	return n;
     82 }
     83 
     84 void
     85 addtoincludepath(dirname)
     86 	const char *dirname;
     87 {
     88 	struct path_entry *n;
     89 
     90 	n = new_path_entry(dirname);
     91 
     92 	if (last) {
     93 		last->next = n;
     94 		last = n;
     95 	}
     96 	else
     97 		last = first = n;
     98 }
     99 
    100 static void
    101 ensure_m4path()
    102 {
    103 	static int envpathdone = 0;
    104 	char *envpath;
    105 	char *sweep;
    106 	char *path;
    107 
    108 	if (envpathdone)
    109 		return;
    110 	envpathdone = TRUE;
    111 	envpath = getenv("M4PATH");
    112 	if (!envpath)
    113 		return;
    114 	/* for portability: getenv result is read-only */
    115 	envpath = strdup(envpath);
    116 	if (!envpath)
    117 		errx(1, "out of memory");
    118 	for (sweep = envpath;
    119 	    (path = strsep(&sweep, ":")) != NULL;)
    120 	    addtoincludepath(path);
    121 	free(envpath);
    122 }
    123 
    124 static
    125 struct input_file *
    126 dopath(i, filename)
    127 	struct input_file *i;
    128 	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(i, filename)
    146 	struct input_file *i;
    147 	const char *filename;
    148 {
    149 	FILE *f;
    150 
    151 	f = fopen(filename, "r");
    152 	if (f != NULL) {
    153 		set_input(i, f, filename);
    154 		return i;
    155 	}
    156 	if (filename[0] == '/')
    157 		return NULL;
    158 
    159 	ensure_m4path();
    160 
    161 	return dopath(i, filename);
    162 }
    163 
    164 void
    165 doindir(argv, argc)
    166 	const char *argv[];
    167 	int argc;
    168 {
    169 	ndptr p;
    170 
    171 	p = lookup(argv[2]);
    172 	if (p == NULL)
    173 		errx(1, "undefined macro %s", argv[2]);
    174 	argv[1] = p->defn;
    175 	eval(argv+1, argc-1, p->type);
    176 }
    177 
    178 void
    179 dobuiltin(argv, argc)
    180 	const char *argv[];
    181 	int argc;
    182 {
    183 	int n;
    184 	argv[1] = NULL;
    185 	n = builtin_type(argv[2]);
    186 	if (n != -1)
    187 		eval(argv+1, argc-1, n);
    188 	else
    189 		errx(1, "unknown builtin %s", argv[2]);
    190 }
    191 
    192 
    193 /* We need some temporary buffer space, as pb pushes BACK and substitution
    194  * proceeds forward... */
    195 static char *buffer;
    196 static size_t bufsize = 0;
    197 static size_t current = 0;
    198 
    199 static void addchars __P((const char *, size_t));
    200 static void addchar __P((char));
    201 static char *twiddle __P((const char *));
    202 static char *getstring __P((void));
    203 static void exit_regerror __P((int, regex_t *));
    204 static void do_subst __P((const char *, regex_t *, const char *, regmatch_t *));
    205 static void do_regexpindex __P((const char *, regex_t *, regmatch_t *));
    206 static void do_regexp __P((const char *, regex_t *, const char *, regmatch_t *));
    207 static void add_sub __P((int, const char *, regex_t *, regmatch_t *));
    208 static void add_replace __P((const char *, regex_t *, const char *, regmatch_t *));
    209 #define addconstantstring(s) addchars((s), sizeof(s)-1)
    210 
    211 static void
    212 addchars(c, n)
    213 	const char *c;
    214 	size_t n;
    215 {
    216 	if (n == 0)
    217 		return;
    218 	while (current + n > bufsize) {
    219 		if (bufsize == 0)
    220 			bufsize = 1024;
    221 		else
    222 			bufsize *= 2;
    223 		buffer = realloc(buffer, bufsize);
    224 		if (buffer == NULL)
    225 			errx(1, "out of memory");
    226 	}
    227 	memcpy(buffer+current, c, n);
    228 	current += n;
    229 }
    230 
    231 static void
    232 addchar(c)
    233 	char c;
    234 {
    235 	if (current +1 > bufsize) {
    236 		if (bufsize == 0)
    237 			bufsize = 1024;
    238 		else
    239 			bufsize *= 2;
    240 		buffer = realloc(buffer, bufsize);
    241 		if (buffer == NULL)
    242 			errx(1, "out of memory");
    243 	}
    244 	buffer[current++] = c;
    245 }
    246 
    247 static char *
    248 getstring()
    249 {
    250 	addchar('\0');
    251 	current = 0;
    252 	return buffer;
    253 }
    254 
    255 
    256 static void
    257 exit_regerror(er, re)
    258 	int er;
    259 	regex_t *re;
    260 {
    261 	size_t 	errlen;
    262 	char 	*errbuf;
    263 
    264 	errlen = regerror(er, re, NULL, 0);
    265 	errbuf = xalloc(errlen);
    266 	regerror(er, re, errbuf, errlen);
    267 	errx(1, "regular expression error: %s", errbuf);
    268 }
    269 
    270 static void
    271 add_sub(n, string, re, pm)
    272 	int n;
    273 	const char *string;
    274 	regex_t *re;
    275 	regmatch_t *pm;
    276 {
    277 	if (n > re->re_nsub)
    278 		warnx("No subexpression %d", n);
    279 	/* Subexpressions that did not match are
    280 	 * not an error.  */
    281 	else if (pm[n].rm_so != -1 &&
    282 	    pm[n].rm_eo != -1) {
    283 		addchars(string + pm[n].rm_so,
    284 			pm[n].rm_eo - pm[n].rm_so);
    285 	}
    286 }
    287 
    288 /* Add replacement string to the output buffer, recognizing special
    289  * constructs and replacing them with substrings of the original string.
    290  */
    291 static void
    292 add_replace(string, re, replace, pm)
    293 	const char *string;
    294 	regex_t *re;
    295 	const char *replace;
    296 	regmatch_t *pm;
    297 {
    298 	const char *p;
    299 
    300 	for (p = replace; *p != '\0'; p++) {
    301 		if (*p == '&' && !mimic_gnu) {
    302 			add_sub(0, string, re, pm);
    303 			continue;
    304 		}
    305 		if (*p == '\\') {
    306 			if (p[1] == '\\') {
    307 				addchar(p[1]);
    308 				p++;
    309 				continue;
    310 			}
    311 			if (p[1] == '&') {
    312 				if (mimic_gnu)
    313 					add_sub(0, string, re, pm);
    314 				else
    315 					addchar(p[1]);
    316 				p++;
    317 				continue;
    318 			}
    319 			if (isdigit(p[1])) {
    320 				add_sub(*(++p) - '0', string, re, pm);
    321 				continue;
    322 			}
    323 		}
    324 	    	addchar(*p);
    325 	}
    326 }
    327 
    328 static void
    329 do_subst(string, re, replace, pm)
    330 	const char *string;
    331 	regex_t *re;
    332 	const char *replace;
    333 	regmatch_t *pm;
    334 {
    335 	int error;
    336 	int flags = 0;
    337 	const char *last_match = NULL;
    338 
    339 	while ((error = regexec(re, string, re->re_nsub+1, pm, flags)) == 0) {
    340 		if (pm[0].rm_eo != 0) {
    341 			if (string[pm[0].rm_eo-1] == '\n')
    342 				flags = 0;
    343 			else
    344 				flags = REG_NOTBOL;
    345 		}
    346 
    347 		/* NULL length matches are special... We use the `vi-mode'
    348 		 * rule: don't allow a NULL-match at the last match
    349 		 * position.
    350 		 */
    351 		if (pm[0].rm_so == pm[0].rm_eo &&
    352 		    string + pm[0].rm_so == last_match) {
    353 			if (*string == '\0')
    354 				return;
    355 			addchar(*string);
    356 			if (*string++ == '\n')
    357 				flags = 0;
    358 			else
    359 				flags = REG_NOTBOL;
    360 			continue;
    361 		}
    362 		last_match = string + pm[0].rm_so;
    363 		addchars(string, pm[0].rm_so);
    364 		add_replace(string, re, replace, pm);
    365 		string += pm[0].rm_eo;
    366 	}
    367 	if (error != REG_NOMATCH)
    368 		exit_regerror(error, re);
    369 	pbstr(string);
    370 }
    371 
    372 static void
    373 do_regexp(string, re, replace, pm)
    374 	const char *string;
    375 	regex_t *re;
    376 	const char *replace;
    377 	regmatch_t *pm;
    378 {
    379 	int error;
    380 
    381 	switch(error = regexec(re, string, re->re_nsub+1, pm, 0)) {
    382 	case 0:
    383 		add_replace(string, re, replace, pm);
    384 		pbstr(getstring());
    385 		break;
    386 	case REG_NOMATCH:
    387 		break;
    388 	default:
    389 		exit_regerror(error, re);
    390 	}
    391 }
    392 
    393 static void
    394 do_regexpindex(string, re, pm)
    395 	const char *string;
    396 	regex_t *re;
    397 	regmatch_t *pm;
    398 {
    399 	int error;
    400 
    401 	switch(error = regexec(re, string, re->re_nsub+1, pm, 0)) {
    402 	case 0:
    403 		pbunsigned(pm[0].rm_so);
    404 		break;
    405 	case REG_NOMATCH:
    406 		pbnum(-1);
    407 		break;
    408 	default:
    409 		exit_regerror(error, re);
    410 	}
    411 }
    412 
    413 /* In Gnu m4 mode, parentheses for backmatch don't work like POSIX 1003.2
    414  * says. So we twiddle with the regexp before passing it to regcomp.
    415  */
    416 static char *
    417 twiddle(p)
    418 	const char *p;
    419 {
    420 	/* This could use strcspn for speed... */
    421 	while (*p != '\0') {
    422 		if (*p == '\\') {
    423 			switch(p[1]) {
    424 			case '(':
    425 			case ')':
    426 			case '|':
    427 				addchar(p[1]);
    428 				break;
    429 			case 'w':
    430 				addconstantstring("[_a-zA-Z0-9]");
    431 				break;
    432 			case 'W':
    433 				addconstantstring("[^_a-zA-Z0-9]");
    434 				break;
    435 			case '<':
    436 				addconstantstring("[[:<:]]");
    437 				break;
    438 			case '>':
    439 				addconstantstring("[[:>:]]");
    440 				break;
    441 			default:
    442 				addchars(p, 2);
    443 				break;
    444 			}
    445 			p+=2;
    446 			continue;
    447 		}
    448 		if (*p == '(' || *p == ')' || *p == '|')
    449 			addchar('\\');
    450 
    451 		addchar(*p);
    452 		p++;
    453 	}
    454 	return getstring();
    455 }
    456 
    457 /* patsubst(string, regexp, opt replacement) */
    458 /* argv[2]: string
    459  * argv[3]: regexp
    460  * argv[4]: opt rep
    461  */
    462 void
    463 dopatsubst(argv, argc)
    464 	const char *argv[];
    465 	int argc;
    466 {
    467 	int error;
    468 	regex_t re;
    469 	regmatch_t *pmatch;
    470 
    471 	if (argc <= 3) {
    472 		warnx("Too few arguments to patsubst");
    473 		return;
    474 	}
    475 	error = regcomp(&re, mimic_gnu ? twiddle(argv[3]) : argv[3],
    476 	    REG_NEWLINE | REG_EXTENDED);
    477 	if (error != 0)
    478 		exit_regerror(error, &re);
    479 
    480 	pmatch = xalloc(sizeof(regmatch_t) * (re.re_nsub+1));
    481 	do_subst(argv[2], &re,
    482 	    argc != 4 && argv[4] != NULL ? argv[4] : "", pmatch);
    483 	pbstr(getstring());
    484 	free(pmatch);
    485 	regfree(&re);
    486 }
    487 
    488 void
    489 doregexp(argv, argc)
    490 	const char *argv[];
    491 	int argc;
    492 {
    493 	int error;
    494 	regex_t re;
    495 	regmatch_t *pmatch;
    496 
    497 	if (argc <= 3) {
    498 		warnx("Too few arguments to regexp");
    499 		return;
    500 	}
    501 	error = regcomp(&re, mimic_gnu ? twiddle(argv[3]) : argv[3],
    502 	    REG_EXTENDED);
    503 	if (error != 0)
    504 		exit_regerror(error, &re);
    505 
    506 	pmatch = xalloc(sizeof(regmatch_t) * (re.re_nsub+1));
    507 	if (argv[4] == NULL || argc == 4)
    508 		do_regexpindex(argv[2], &re, pmatch);
    509 	else
    510 		do_regexp(argv[2], &re, argv[4], pmatch);
    511 	free(pmatch);
    512 	regfree(&re);
    513 }
    514 
    515 void
    516 doesyscmd(cmd)
    517 	const char *cmd;
    518 {
    519 	int p[2];
    520 	pid_t pid, cpid;
    521 	char *argv[4];
    522 	int cc;
    523 	int status;
    524 
    525 	/* Follow gnu m4 documentation: first flush buffers. */
    526 	fflush(NULL);
    527 
    528 	argv[0] = "sh";
    529 	argv[1] = "-c";
    530 	argv[2] = (char *)cmd;
    531 	argv[3] = NULL;
    532 
    533 	/* Just set up standard output, share stderr and stdin with m4 */
    534 	if (pipe(p) == -1)
    535 		err(1, "bad pipe");
    536 	switch(cpid = fork()) {
    537 	case -1:
    538 		err(1, "bad fork");
    539 		/* NOTREACHED */
    540 	case 0:
    541 		(void) close(p[0]);
    542 		(void) dup2(p[1], 1);
    543 		(void) close(p[1]);
    544 		execv(_PATH_BSHELL, argv);
    545 		exit(1);
    546 	default:
    547 		/* Read result in two stages, since m4's buffer is
    548 		 * pushback-only. */
    549 		(void) close(p[1]);
    550 		do {
    551 			char result[BUFSIZE];
    552 			cc = read(p[0], result, sizeof result);
    553 			if (cc > 0)
    554 				addchars(result, cc);
    555 		} while (cc > 0 || (cc == -1 && errno == EINTR));
    556 
    557 		(void) close(p[0]);
    558 		while ((pid = wait(&status)) != cpid && pid >= 0)
    559 			continue;
    560 		pbstr(getstring());
    561 	}
    562 }
    563