gnum4.c revision 298190 
1/* $OpenBSD: gnum4.c,v 1.50 2015/04/29 00:13:26 millert 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#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/usr.bin/m4/gnum4.c 298190 2016-04-18 07:09:34Z araujo $");
29
30/*
31 * functions needed to support gnu-m4 extensions, including a fake freezing
32 */
33
34#include <sys/types.h>
35#include <sys/wait.h>
36#include <ctype.h>
37#include <err.h>
38#include <paths.h>
39#include <regex.h>
40#include <stddef.h>
41#include <stdlib.h>
42#include <stdint.h>
43#include <stdio.h>
44#include <string.h>
45#include <errno.h>
46#include <unistd.h>
47#include <limits.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 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
63static struct 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 = xstrdup(dirname);
81	n->next = 0;
82	return n;
83}
84
85void
86addtoincludepath(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
100static void
101ensure_m4path(void)
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 = xstrdup(envpath);
116	for (sweep = envpath;
117	    (path = strsep(&sweep, ":")) != NULL;)
118	    addtoincludepath(path);
119	free(envpath);
120}
121
122static
123struct input_file *
124dopath(struct input_file *i, const char *filename)
125{
126	char path[PATH_MAX];
127	struct path_entry *pe;
128	FILE *f;
129
130	for (pe = first; pe; pe = pe->next) {
131		snprintf(path, sizeof(path), "%s/%s", pe->name, filename);
132		if ((f = fopen(path, "r")) != NULL) {
133			set_input(i, f, path);
134			return i;
135		}
136	}
137	return NULL;
138}
139
140struct input_file *
141fopen_trypath(struct input_file *i, const char *filename)
142{
143	FILE *f;
144
145	f = fopen(filename, "r");
146	if (f != NULL) {
147		set_input(i, f, filename);
148		return i;
149	}
150	if (filename[0] == '/')
151		return NULL;
152
153	ensure_m4path();
154
155	return dopath(i, filename);
156}
157
158void
159doindir(const char *argv[], int argc)
160{
161	ndptr n;
162	struct macro_definition *p = NULL;
163
164	n = lookup(argv[2]);
165	if (n == NULL || (p = macro_getdef(n)) == NULL)
166		m4errx(1, "indir: undefined macro %s.", argv[2]);
167	argv[1] = p->defn;
168
169	eval(argv+1, argc-1, p->type, is_traced(n));
170}
171
172void
173dobuiltin(const char *argv[], int argc)
174{
175	ndptr p;
176
177	argv[1] = NULL;
178	p = macro_getbuiltin(argv[2]);
179	if (p != NULL)
180		eval(argv+1, argc-1, macro_builtin_type(p), is_traced(p));
181	else
182		m4errx(1, "unknown builtin %s.", argv[2]);
183}
184
185
186/* We need some temporary buffer space, as pb pushes BACK and substitution
187 * proceeds forward... */
188static char *buffer;
189static size_t bufsize = 0;
190static size_t current = 0;
191
192static void addchars(const char *, size_t);
193static void addchar(int);
194static char *twiddle(const char *);
195static char *getstring(void);
196static void exit_regerror(int, regex_t *, const char *);
197static void do_subst(const char *, regex_t *, const char *, const char *,
198    regmatch_t *);
199static void do_regexpindex(const char *, regex_t *, const char *, regmatch_t *);
200static void do_regexp(const char *, regex_t *, const char *, const char *,
201    regmatch_t *);
202static void add_sub(int, const char *, regex_t *, regmatch_t *);
203static void add_replace(const char *, regex_t *, const char *, regmatch_t *);
204#define addconstantstring(s) addchars((s), sizeof(s)-1)
205
206static void
207addchars(const char *c, size_t n)
208{
209	if (n == 0)
210		return;
211	while (current + n > bufsize) {
212		if (bufsize == 0)
213			bufsize = 1024;
214		else if (bufsize <= SIZE_MAX/2) {
215			bufsize *= 2;
216		} else {
217			errx(1, "size overflow");
218		}
219		buffer = xrealloc(buffer, bufsize, NULL);
220	}
221	memcpy(buffer+current, c, n);
222	current += n;
223}
224
225static void
226addchar(int c)
227{
228	if (current +1 > bufsize) {
229		if (bufsize == 0)
230			bufsize = 1024;
231		else
232			bufsize *= 2;
233		buffer = xrealloc(buffer, bufsize, NULL);
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, const char *source)
249{
250	size_t	errlen;
251	char	*errbuf;
252
253	errlen = regerror(er, re, NULL, 0);
254	errbuf = xalloc(errlen,
255	    "malloc in regerror: %lu", (unsigned long)errlen);
256	regerror(er, re, errbuf, errlen);
257	m4errx(1, "regular expression error in %s: %s.", source, errbuf);
258}
259
260static void
261add_sub(int n, const char *string, regex_t *re, regmatch_t *pm)
262{
263	if (n > (int)re->re_nsub)
264		warnx("No subexpression %d", n);
265	/* Subexpressions that did not match are
266	 * not an error.  */
267	else if (pm[n].rm_so != -1 &&
268	    pm[n].rm_eo != -1) {
269		addchars(string + pm[n].rm_so,
270			pm[n].rm_eo - pm[n].rm_so);
271	}
272}
273
274/* Add replacement string to the output buffer, recognizing special
275 * constructs and replacing them with substrings of the original string.
276 */
277static void
278add_replace(const char *string, regex_t *re, const char *replace, regmatch_t *pm)
279{
280	const char *p;
281
282	for (p = replace; *p != '\0'; p++) {
283		if (*p == '&' && !mimic_gnu) {
284			add_sub(0, string, re, pm);
285			continue;
286		}
287		if (*p == '\\') {
288			if (p[1] == '\\') {
289				addchar(p[1]);
290				p++;
291				continue;
292			}
293			if (p[1] == '&') {
294				if (mimic_gnu)
295					add_sub(0, string, re, pm);
296				else
297					addchar(p[1]);
298				p++;
299				continue;
300			}
301			if (isdigit((unsigned char)p[1])) {
302				add_sub(*(++p) - '0', string, re, pm);
303				continue;
304			}
305		}
306		addchar(*p);
307	}
308}
309
310static void
311do_subst(const char *string, regex_t *re, const char *source,
312    const char *replace, regmatch_t *pm)
313{
314	int error;
315	int flags = 0;
316	const char *last_match = NULL;
317
318	while ((error = regexec(re, string, re->re_nsub+1, pm, flags)) == 0) {
319		if (pm[0].rm_eo != 0) {
320			if (string[pm[0].rm_eo-1] == '\n')
321				flags = 0;
322			else
323				flags = REG_NOTBOL;
324		}
325
326		/* NULL length matches are special... We use the `vi-mode'
327		 * rule: don't allow a NULL-match at the last match
328		 * position.
329		 */
330		if (pm[0].rm_so == pm[0].rm_eo &&
331		    string + pm[0].rm_so == last_match) {
332			if (*string == '\0')
333				return;
334			addchar(*string);
335			if (*string++ == '\n')
336				flags = 0;
337			else
338				flags = REG_NOTBOL;
339			continue;
340		}
341		last_match = string + pm[0].rm_so;
342		addchars(string, pm[0].rm_so);
343		add_replace(string, re, replace, pm);
344		string += pm[0].rm_eo;
345	}
346	if (error != REG_NOMATCH)
347		exit_regerror(error, re, source);
348	pbstr(string);
349}
350
351static void
352do_regexp(const char *string, regex_t *re, const char *source,
353    const char *replace, regmatch_t *pm)
354{
355	int error;
356
357	switch(error = regexec(re, string, re->re_nsub+1, pm, 0)) {
358	case 0:
359		add_replace(string, re, replace, pm);
360		pbstr(getstring());
361		break;
362	case REG_NOMATCH:
363		break;
364	default:
365		exit_regerror(error, re, source);
366	}
367}
368
369static void
370do_regexpindex(const char *string, regex_t *re, const char *source,
371    regmatch_t *pm)
372{
373	int error;
374
375	switch(error = regexec(re, string, re->re_nsub+1, pm, 0)) {
376	case 0:
377		pbunsigned(pm[0].rm_so);
378		break;
379	case REG_NOMATCH:
380		pbnum(-1);
381		break;
382	default:
383		exit_regerror(error, re, source);
384	}
385}
386
387/* In Gnu m4 mode, parentheses for backmatch don't work like POSIX 1003.2
388 * says. So we twiddle with the regexp before passing it to regcomp.
389 */
390static char *
391twiddle(const char *p)
392{
393	/* + at start of regexp is a normal character for Gnu m4 */
394	if (*p == '^') {
395		addchar(*p);
396		p++;
397	}
398	if (*p == '+') {
399		addchar('\\');
400	}
401	/* This could use strcspn for speed... */
402	while (*p != '\0') {
403		if (*p == '\\') {
404			switch(p[1]) {
405			case '(':
406			case ')':
407			case '|':
408				addchar(p[1]);
409				break;
410			case 'w':
411				addconstantstring("[_a-zA-Z0-9]");
412				break;
413			case 'W':
414				addconstantstring("[^_a-zA-Z0-9]");
415				break;
416			case '<':
417				addconstantstring("[[:<:]]");
418				break;
419			case '>':
420				addconstantstring("[[:>:]]");
421				break;
422			default:
423				addchars(p, 2);
424				break;
425			}
426			p+=2;
427			continue;
428		}
429		if (*p == '(' || *p == ')' || *p == '|')
430			addchar('\\');
431
432		addchar(*p);
433		p++;
434	}
435	return getstring();
436}
437
438/* patsubst(string, regexp, opt replacement) */
439/* argv[2]: string
440 * argv[3]: regexp
441 * argv[4]: opt rep
442 */
443void
444dopatsubst(const char *argv[], int argc)
445{
446	if (argc <= 3) {
447		warnx("Too few arguments to patsubst");
448		return;
449	}
450	/* special case: empty regexp */
451	if (argv[3][0] == '\0') {
452		const char *s;
453		size_t len;
454		if (argc > 4 && argv[4])
455			len = strlen(argv[4]);
456		else
457			len = 0;
458		for (s = argv[2]; *s != '\0'; s++) {
459			addchars(argv[4], len);
460			addchar(*s);
461		}
462	} else {
463		int error;
464		regex_t re;
465		regmatch_t *pmatch;
466		int mode = REG_EXTENDED;
467		const char *source;
468		size_t l = strlen(argv[3]);
469
470		if (!mimic_gnu ||
471		    (argv[3][0] == '^') ||
472		    (l > 0 && argv[3][l-1] == '$'))
473			mode |= REG_NEWLINE;
474
475		source = mimic_gnu ? twiddle(argv[3]) : argv[3];
476		error = regcomp(&re, source, mode);
477		if (error != 0)
478			exit_regerror(error, &re, source);
479
480		pmatch = xreallocarray(NULL, re.re_nsub+1, sizeof(regmatch_t),
481		    NULL);
482		do_subst(argv[2], &re, source,
483		    argc > 4 && argv[4] != NULL ? argv[4] : "", pmatch);
484		free(pmatch);
485		regfree(&re);
486	}
487	pbstr(getstring());
488}
489
490void
491doregexp(const char *argv[], int argc)
492{
493	int error;
494	regex_t re;
495	regmatch_t *pmatch;
496	const char *source;
497
498	if (argc <= 3) {
499		warnx("Too few arguments to regexp");
500		return;
501	}
502	/* special gnu case */
503	if (argv[3][0] == '\0' && mimic_gnu) {
504		if (argc == 4 || argv[4] == NULL)
505			return;
506		else
507			pbstr(argv[4]);
508	}
509	source = mimic_gnu ? twiddle(argv[3]) : argv[3];
510	error = regcomp(&re, source, REG_EXTENDED|REG_NEWLINE);
511	if (error != 0)
512		exit_regerror(error, &re, source);
513
514	pmatch = xreallocarray(NULL, re.re_nsub+1, sizeof(regmatch_t), NULL);
515	if (argc == 4 || argv[4] == NULL)
516		do_regexpindex(argv[2], &re, source, pmatch);
517	else
518		do_regexp(argv[2], &re, source, argv[4], pmatch);
519	free(pmatch);
520	regfree(&re);
521}
522
523void
524doformat(const char *argv[], int argc)
525{
526	const char *format = argv[2];
527	int pos = 3;
528	int left_padded;
529	long width;
530	size_t l;
531	const char *thisarg = NULL;
532	char temp[2];
533	long extra;
534
535	while (*format != 0) {
536		if (*format != '%') {
537			addchar(*format++);
538			continue;
539		}
540
541		format++;
542		if (*format == '%') {
543			addchar(*format++);
544			continue;
545		}
546		if (*format == 0) {
547			addchar('%');
548			break;
549		}
550
551		if (*format == '*') {
552			format++;
553			if (pos >= argc)
554				m4errx(1,
555				    "Format with too many format specifiers.");
556			width = strtol(argv[pos++], NULL, 10);
557		} else {
558			width = strtol(format, __DECONST(char **,&format), 10);
559		}
560		if (width < 0) {
561			left_padded = 1;
562			width = -width;
563		} else {
564			left_padded = 0;
565		}
566		if (*format == '.') {
567			format++;
568			if (*format == '*') {
569				format++;
570				if (pos >= argc)
571					m4errx(1,
572					    "Format with too many format specifiers.");
573				extra = strtol(argv[pos++], NULL, 10);
574			} else {
575				extra = strtol(format, __DECONST(char **, &format), 10);
576			}
577		} else {
578			extra = LONG_MAX;
579		}
580		if (pos >= argc)
581			m4errx(1, "Format with too many format specifiers.");
582		switch(*format) {
583		case 's':
584			thisarg = argv[pos++];
585			break;
586		case 'c':
587			temp[0] = strtoul(argv[pos++], NULL, 10);
588			temp[1] = 0;
589			thisarg = temp;
590			break;
591		default:
592			m4errx(1, "Unsupported format specification: %s.",
593			    argv[2]);
594		}
595		format++;
596		l = strlen(thisarg);
597		if ((long)l > extra)
598			l = extra;
599		if (!left_padded) {
600			while ((long)l < width--)
601				addchar(' ');
602		}
603		addchars(thisarg, l);
604		if (left_padded) {
605			while ((long)l < width--)
606				addchar(' ');
607		}
608	}
609	pbstr(getstring());
610}
611
612void
613doesyscmd(const char *cmd)
614{
615	int p[2];
616	pid_t pid, cpid;
617	char *argv[4];
618	int cc;
619	int status;
620
621	/* Follow gnu m4 documentation: first flush buffers. */
622	fflush(NULL);
623
624	argv[0] = __DECONST(char *, "sh");
625	argv[1] = __DECONST(char *, "-c");
626	argv[2] = __DECONST(char *, cmd);
627	argv[3] = NULL;
628
629	/* Just set up standard output, share stderr and stdin with m4 */
630	if (pipe(p) == -1)
631		err(1, "bad pipe");
632	switch(cpid = fork()) {
633	case -1:
634		err(1, "bad fork");
635		/* NOTREACHED */
636	case 0:
637		(void) close(p[0]);
638		(void) dup2(p[1], 1);
639		(void) close(p[1]);
640		execv(_PATH_BSHELL, argv);
641		exit(1);
642	default:
643		/* Read result in two stages, since m4's buffer is
644		 * pushback-only. */
645		(void) close(p[1]);
646		do {
647			char result[BUFSIZE];
648			cc = read(p[0], result, sizeof result);
649			if (cc > 0)
650				addchars(result, cc);
651		} while (cc > 0 || (cc == -1 && errno == EINTR));
652
653		(void) close(p[0]);
654		while ((pid = wait(&status)) != cpid && pid >= 0)
655			continue;
656		pbstr(getstring());
657	}
658}
659
660void
661getdivfile(const char *name)
662{
663	FILE *f;
664	int c;
665
666	f = fopen(name, "r");
667	if (!f)
668		return;
669
670	while ((c = getc(f))!= EOF)
671		putc(c, active);
672	(void) fclose(f);
673}
674