gnum4.c revision 100014 
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
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/usr.bin/m4/gnum4.c 100014 2002-07-15 02:15:12Z jmallett $");
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
53int 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
63struct path_entry {
64	char *name;
65	struct path_entry *next;
66} *first, *last;
67
68static struct path_entry *new_path_entry(const char *);
69static void ensure_m4path(void);
70static struct input_file *dopath(struct input_file *, const char *);
71
72static struct path_entry *
73new_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
87void
88addtoincludepath(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
102static void
103ensure_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
126static
127struct input_file *
128dopath(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
144struct input_file *
145fopen_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
162void
163doindir(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
174void
175dobuiltin(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... */
189static char *buffer;
190static size_t bufsize = 0;
191static size_t current = 0;
192
193static void addchars(const char *, size_t);
194static void addchar(int);
195static char *twiddle(const char *);
196static char *getstring(void);
197static void exit_regerror(int, regex_t *);
198static void do_subst(const char *, regex_t *, const char *, regmatch_t *);
199static void do_regexpindex(const char *, regex_t *, regmatch_t *);
200static void do_regexp(const char *, regex_t *, const char *, regmatch_t *);
201static void add_sub(size_t, const char *, regex_t *, regmatch_t *);
202static void add_replace(const char *, regex_t *, const char *, regmatch_t *);
203#define addconstantstring(s) addchars((s), sizeof(s)-1)
204
205static void
206addchars(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
223static void
224addchar(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
238static char *
239getstring(void)
240{
241	addchar('\0');
242	current = 0;
243	return buffer;
244}
245
246
247static void
248exit_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
259static void
260add_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 */
276static void
277add_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
309static void
310do_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
349static void
350do_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
366static void
367do_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 */
386static char *
387twiddle(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 */
431void
432dopatsubst(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
455void
456doregexp(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
480void
481doesyscmd(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}
521