xref: /netbsd-src/usr.bin/man/man.c (revision bfb6cb13d599546df69c7e4d20d70e22e15a549d)
1 /*	$NetBSD: man.c,v 1.35 2007/02/05 19:46:24 jwise Exp $	*/
2 
3 /*
4  * Copyright (c) 1987, 1993, 1994, 1995
5  *	The Regents of the University of California.  All rights reserved.
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  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 
34 #ifndef lint
35 __COPYRIGHT("@(#) Copyright (c) 1987, 1993, 1994, 1995\n\
36 	The Regents of the University of California.  All rights reserved.\n");
37 #endif /* not lint */
38 
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)man.c	8.17 (Berkeley) 1/31/95";
42 #else
43 __RCSID("$NetBSD: man.c,v 1.35 2007/02/05 19:46:24 jwise Exp $");
44 #endif
45 #endif /* not lint */
46 
47 #include <sys/param.h>
48 #include <sys/queue.h>
49 #include <sys/utsname.h>
50 
51 #include <ctype.h>
52 #include <err.h>
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <fnmatch.h>
56 #include <glob.h>
57 #include <signal.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <unistd.h>
62 
63 #include "manconf.h"
64 #include "pathnames.h"
65 
66 #ifndef MAN_DEBUG
67 #define MAN_DEBUG 0		/* debug path output */
68 #endif
69 
70 /*
71  * manstate: structure collecting the current global state so we can
72  * easily identify it and pass it to helper functions in one arg.
73  */
74 struct manstate {
75 	/* command line flags */
76 	int all;		/* -a: show all matches rather than first */
77 	int cat;		/* -c: do not use a pager */
78 	char *conffile;		/* -C: use alternate config file */
79 	int how;		/* -h: show SYNOPSIS only */
80 	char *manpath;		/* -M: alternate MANPATH */
81 	char *addpath;		/* -m: add these dirs to front of manpath */
82 	char *pathsearch;	/* -S: path of man must contain this string */
83 	char *sectionname;	/* -s: limit search to a given man section */
84 	int where;		/* -w: just show paths of all matching files */
85 
86 	/* important tags from the config file */
87 	TAG *defaultpath;	/* _default: default MANPATH */
88 	TAG *subdirs;		/* _subdir: default subdir search list */
89 	TAG *suffixlist;	/* _suffix: for files that can be cat()'d */
90 	TAG *buildlist;		/* _build: for files that must be built */
91 
92 	/* tags for internal use */
93 	TAG *intmp;		/* _intmp: tmp files we must cleanup */
94 	TAG *missinglist;	/* _missing: pages we couldn't find */
95 	TAG *mymanpath;		/* _new_path: final version of MANPATH */
96 	TAG *section;		/* <sec>: tag for m.sectionname */
97 
98 	/* other misc stuff */
99 	const char *pager;	/* pager to use */
100 	size_t pagerlen;	/* length of the above */
101 };
102 
103 /*
104  * prototypes
105  */
106 int		 main(int, char **);
107 static void	 build_page(char *, char **, struct manstate *);
108 static void	 cat(char *);
109 static const char	*check_pager(const char *);
110 static int	 cleanup(void);
111 static void	 how(char *);
112 static void	 jump(char **, char *, char *);
113 static int	 manual(char *, struct manstate *, glob_t *);
114 static void	 onsig(int);
115 static void	 usage(void);
116 
117 /*
118  * main function
119  */
120 int
121 main(int argc, char **argv)
122 {
123 	static struct manstate m = { 0 }; 	/* init to zero */
124 	int ch, abs_section, found;
125 	const char *machine;
126 	ENTRY *esubd, *epath;
127 	char *p, **ap, *cmd, buf[MAXPATHLEN * 2];
128 	size_t len;
129 	glob_t pg;
130 
131 	/*
132 	 * parse command line...
133 	 */
134 	while ((ch = getopt(argc, argv, "-aC:cfhkM:m:P:s:S:w")) != -1)
135 		switch (ch) {
136 		case 'a':
137 			m.all = 1;
138 			break;
139 		case 'C':
140 			m.conffile = optarg;
141 			break;
142 		case 'c':
143 		case '-':	/* XXX: '-' is a deprecated version of '-c' */
144 			m.cat = 1;
145 			break;
146 		case 'h':
147 			m.how = 1;
148 			break;
149 		case 'm':
150 			m.addpath = optarg;
151 			break;
152 		case 'M':
153 		case 'P':	/* -P for backward compatibility */
154 			m.manpath = strdup(optarg);
155 			break;
156 		/*
157 		 * The -f and -k options are backward compatible,
158 		 * undocumented ways of calling whatis(1) and apropos(1).
159 		 */
160 		case 'f':
161 			jump(argv, "-f", "whatis");
162 			/* NOTREACHED */
163 		case 'k':
164 			jump(argv, "-k", "apropos");
165 			/* NOTREACHED */
166 		case 's':
167 			if (m.sectionname != NULL)
168 				usage();
169 			m.sectionname = optarg;
170 			break;
171 		case 'S':
172 			m.pathsearch = optarg;
173 			break;
174 		case 'w':
175 			m.all = m.where = 1;
176 			break;
177 		case '?':
178 		default:
179 			usage();
180 		}
181 	argc -= optind;
182 	argv += optind;
183 
184 	if (!argc)
185 		usage();
186 
187 	/*
188 	 * read the configuration file and collect any other information
189 	 * we will need (machine type, pager, section [if specified
190 	 * without '-s'], and MANPATH through the environment).
191 	 */
192 	config(m.conffile);    /* exits on error ... */
193 
194 	if ((machine = getenv("MACHINE")) == NULL) {
195 		struct utsname utsname;
196 
197 		if (uname(&utsname) == -1) {
198 			perror("uname");
199 			exit(1);
200 		}
201 		machine = utsname.machine;
202 	}
203 
204 	if (!m.cat && !m.how && !m.where) {  /* if we need a pager ... */
205 		if (!isatty(STDOUT_FILENO)) {
206 			m.cat = 1;
207 		} else {
208 			if ((m.pager = getenv("PAGER")) != NULL &&
209 			    m.pager[0] != '\0')
210 				m.pager = check_pager(m.pager);
211 			else
212 				m.pager = _PATH_PAGER;
213 			m.pagerlen = strlen(m.pager);
214 		}
215 	}
216 
217 	/* do we need to set m.section to a non-null value? */
218 	if (m.sectionname) {
219 
220 		m.section = gettag(m.sectionname, 0); /* -s must be a section */
221 		if (m.section == NULL)
222 			errx(1, "unknown section: %s", m.sectionname);
223 
224 	} else if (argc > 1) {
225 
226 		m.section = gettag(*argv, 0);  /* might be a section? */
227 		if (m.section) {
228 			argv++;
229 			argc--;
230 		}
231 
232 	}
233 
234 	if (m.manpath == NULL)
235 		m.manpath = getenv("MANPATH"); /* note: -M overrides getenv */
236 
237 
238 	/*
239 	 * get default values from config file, plus create the tags we
240 	 * use for keeping internal state.  make sure all our mallocs
241 	 * go through.
242 	 */
243 	/* from cfg file */
244 	m.defaultpath = gettag("_default", 1);
245 	m.subdirs = gettag("_subdir", 1);
246 	m.suffixlist = gettag("_suffix", 1);
247 	m.buildlist = gettag("_build", 1);
248 	/* internal use */
249 	m.mymanpath = gettag("_new_path", 1);
250 	m.missinglist = gettag("_missing", 1);
251 	m.intmp = gettag("_intmp", 1);
252 	if (!m.defaultpath || !m.subdirs || !m.suffixlist || !m.buildlist ||
253 	    !m.mymanpath || !m.missinglist || !m.intmp)
254 		errx(1, "malloc failed");
255 
256 	/*
257 	 * are we using a section whose elements are all absolute paths?
258 	 * (we only need to look at the first entry on the section list,
259 	 * as config() will ensure that any additional entries will match
260 	 * the first one.)
261 	 */
262 	abs_section = (m.section != NULL &&
263 		!TAILQ_EMPTY(&m.section->entrylist) &&
264 	    		*(TAILQ_FIRST(&m.section->entrylist)->s) == '/');
265 
266 	/*
267 	 * now that we have all the data we need, we must determine the
268 	 * manpath we are going to use to find the requested entries using
269 	 * the following steps...
270 	 *
271 	 * [1] if the user specified a section and that section's elements
272 	 *     from the config file are all absolute paths, then we override
273 	 *     defaultpath and -M/MANPATH with the section's absolute paths.
274 	 */
275 	if (abs_section) {
276 		m.manpath = NULL;	   	/* ignore -M/MANPATH */
277 		m.defaultpath = m.section;	/* overwrite _default path */
278 		m.section = NULL;		/* promoted to defaultpath */
279 	}
280 
281 	/*
282 	 * [2] section can now only be non-null if the user asked for
283 	 *     a section and that section's elements did not have
284          *     absolute paths.  in this case we use the section's
285 	 *     elements to override _subdir from the config file.
286 	 *
287 	 * after this step, we are done processing "m.section"...
288 	 */
289 	if (m.section)
290 		m.subdirs = m.section;
291 
292 	/*
293 	 * [3] we need to setup the path we want to use (m.mymanpath).
294 	 *     if the user gave us a path (m.manpath) use it, otherwise
295 	 *     go with the default.   in either case we need to append
296 	 *     the subdir and machine spec to each element of the path.
297 	 *
298 	 *     for absolute section paths that come from the config file,
299 	 *     we only append the subdir spec if the path ends in
300 	 *     a '/' --- elements that do not end in '/' are assumed to
301 	 *     not have subdirectories.  this is mainly for backward compat,
302 	 *     but it allows non-subdir configs like:
303 	 *	sect3       /usr/share/man/{old/,}cat3
304 	 *	doc         /usr/{pkg,share}/doc/{sendmail/op,sendmail/intro}
305 	 *
306 	 *     note that we try and be careful to not put double slashes
307 	 *     in the path (e.g. we want /usr/share/man/man1, not
308 	 *     /usr/share/man//man1) because "more" will put the filename
309 	 *     we generate in its prompt and the double slashes look ugly.
310 	 */
311 	if (m.manpath) {
312 
313 		/* note: strtok is going to destroy m.manpath */
314 		for (p = strtok(m.manpath, ":") ; p ; p = strtok(NULL, ":")) {
315 			len = strlen(p);
316 			if (len < 1)
317 				continue;
318 			TAILQ_FOREACH(esubd, &m.subdirs->entrylist, q) {
319 				snprintf(buf, sizeof(buf), "%s%s%s{/%s,}",
320 					 p, (p[len-1] == '/') ? "" : "/",
321 					 esubd->s, machine);
322 				if (addentry(m.mymanpath, buf, 0) < 0)
323 					errx(1, "malloc failed");
324 			}
325 		}
326 
327 	} else {
328 
329 		TAILQ_FOREACH(epath, &m.defaultpath->entrylist, q) {
330 			/* handle trailing "/" magic here ... */
331 		  	if (abs_section &&
332 			    epath->s[epath->len - 1] != '/') {
333 
334 				(void)snprintf(buf, sizeof(buf),
335 				    "%s{/%s,}", epath->s, machine);
336 				if (addentry(m.mymanpath, buf, 0) < 0)
337 					errx(1, "malloc failed");
338 				continue;
339 			}
340 
341 			TAILQ_FOREACH(esubd, &m.subdirs->entrylist, q) {
342 				snprintf(buf, sizeof(buf), "%s%s%s{/%s,}",
343 					 epath->s,
344 					 (epath->s[epath->len-1] == '/') ? ""
345 									 : "/",
346 					 esubd->s, machine);
347 				if (addentry(m.mymanpath, buf, 0) < 0)
348 					errx(1, "malloc failed");
349 			}
350 		}
351 
352 	}
353 
354 	/*
355 	 * [4] finally, prepend the "-m" m.addpath to mymanpath if it
356 	 *     was specified.   subdirs and machine are always applied to
357 	 *     m.addpath.
358 	 */
359 	if (m.addpath) {
360 
361 		/* note: strtok is going to destroy m.addpath */
362 		for (p = strtok(m.addpath, ":") ; p ; p = strtok(NULL, ":")) {
363 			len = strlen(p);
364 			if (len < 1)
365 				continue;
366 			TAILQ_FOREACH(esubd, &m.subdirs->entrylist, q) {
367 				snprintf(buf, sizeof(buf), "%s%s%s{/%s,}",
368 					 p, (p[len-1] == '/') ? "" : "/",
369 					 esubd->s, machine);
370 				/* add at front */
371 				if (addentry(m.mymanpath, buf, 1) < 0)
372 					errx(1, "malloc failed");
373 			}
374 		}
375 
376 	}
377 
378 	/*
379 	 * now m.mymanpath is complete!
380 	 */
381 #if MAN_DEBUG
382 	printf("mymanpath:\n");
383 	TAILQ_FOREACH(epath, &m.mymanpath->entrylist, q) {
384 		printf("\t%s\n", epath->s);
385 	}
386 #endif
387 
388 	/*
389 	 * start searching for matching files and format them if necessary.
390 	 * setup an interrupt handler so that we can ensure that temporary
391 	 * files go away.
392 	 */
393 	(void)signal(SIGINT, onsig);
394 	(void)signal(SIGHUP, onsig);
395 	(void)signal(SIGPIPE, onsig);
396 
397 	memset(&pg, 0, sizeof(pg));
398 	for (found = 0; *argv; ++argv)
399 		if (manual(*argv, &m, &pg)) {
400 			found = 1;
401 		}
402 
403 	/* if nothing found, we're done. */
404 	if (!found) {
405 		(void)cleanup();
406 		exit (1);
407 	}
408 
409 	/*
410 	 * handle the simple display cases first (m.cat, m.how, m.where)
411 	 */
412 	if (m.cat) {
413 		for (ap = pg.gl_pathv; *ap != NULL; ++ap) {
414 			if (**ap == '\0')
415 				continue;
416 			cat(*ap);
417 		}
418 		exit (cleanup());
419 	}
420 	if (m.how) {
421 		for (ap = pg.gl_pathv; *ap != NULL; ++ap) {
422 			if (**ap == '\0')
423 				continue;
424 			how(*ap);
425 		}
426 		exit(cleanup());
427 	}
428 	if (m.where) {
429 		for (ap = pg.gl_pathv; *ap != NULL; ++ap) {
430 			if (**ap == '\0')
431 				continue;
432 			(void)printf("%s\n", *ap);
433 		}
434 		exit(cleanup());
435 	}
436 
437 	/*
438 	 * normal case - we display things in a single command, so
439          * build a list of things to display.  first compute total
440 	 * length of buffer we will need so we can malloc it.
441 	 */
442 	for (ap = pg.gl_pathv, len = m.pagerlen + 1; *ap != NULL; ++ap) {
443 		if (**ap == '\0')
444 			continue;
445 		len += strlen(*ap) + 1;
446 	}
447 	if ((cmd = malloc(len)) == NULL) {
448 		warn("malloc");
449 		(void)cleanup();
450 		exit(1);
451 	}
452 
453 	/* now build the command string... */
454 	p = cmd;
455 	len = m.pagerlen;
456 	memcpy(p, m.pager, len);
457 	p += len;
458 	*p++ = ' ';
459 	for (ap = pg.gl_pathv; *ap != NULL; ++ap) {
460 		if (**ap == '\0')
461 			continue;
462 		len = strlen(*ap);
463 		memcpy(p, *ap, len);
464 		p += len;
465 		*p++ = ' ';
466 	}
467 	*--p = '\0';
468 
469 	/* Use system(3) in case someone's pager is "pager arg1 arg2". */
470 	(void)system(cmd);
471 
472 	exit(cleanup());
473 }
474 
475 /*
476  * manual --
477  *	Search the manuals for the pages.
478  */
479 static int
480 manual(char *page, struct manstate *mp, glob_t *pg)
481 {
482 	ENTRY *suffix, *mdir;
483 	int anyfound, error, found;
484 	size_t cnt;
485 	char *p, buf[MAXPATHLEN], *escpage, *eptr;
486 	static const char escglob[] = "\\~?*{}[]";
487 
488 	anyfound = 0;
489 
490 	/*
491 	 * Fixup page which may contain glob(3) special characters, e.g.
492 	 * the famous "No man page for [" FAQ.
493 	 */
494 	if ((escpage = malloc((2 * strlen(page)) + 1)) == NULL) {
495 		warn("malloc");
496 		(void)cleanup();
497 		exit(1);
498 	}
499 
500 	p = page;
501 	eptr = escpage;
502 
503 	while (*p) {
504 		if (strchr(escglob, *p) != NULL) {
505 			*eptr++ = '\\';
506 			*eptr++ = *p++;
507 		} else
508 			*eptr++ = *p++;
509 	}
510 
511 	*eptr = '\0';
512 
513 	/* For each man directory in mymanpath ... */
514 	TAILQ_FOREACH(mdir, &mp->mymanpath->entrylist, q) {
515 
516 		/*
517 		 * use glob(3) to look in the filesystem for matching files.
518 		 * match any suffix here, as we will check that later.
519 		 */
520 		(void)snprintf(buf, sizeof(buf), "%s/%s.*", mdir->s, escpage);
521 		if ((error = glob(buf,
522 		    GLOB_APPEND | GLOB_BRACE | GLOB_NOSORT, NULL, pg)) != 0) {
523 			if (error == GLOB_NOMATCH)
524 				continue;
525 			else {
526 				warn("globbing");
527 				(void)cleanup();
528 				exit(1);
529 			}
530 		}
531 		if (pg->gl_matchc == 0)
532 			continue;
533 
534 		/*
535 		 * start going through the matches glob(3) just found and
536 		 * use m.pathsearch (if present) to filter out pages we
537 		 * don't want.  then verify the suffix is valid, and build
538 		 * the page if we have a _build suffix.
539 		 */
540 		for (cnt = pg->gl_pathc - pg->gl_matchc;
541 		    cnt < pg->gl_pathc; ++cnt) {
542 
543 			/* filter on directory path name */
544 			if (mp->pathsearch) {
545 				p = strstr(pg->gl_pathv[cnt], mp->pathsearch);
546 				if (!p || strchr(p, '/') == NULL) {
547 					pg->gl_pathv[cnt] = ""; /* zap! */
548 					continue;
549 				}
550 			}
551 
552 			/*
553 			 * Try the _suffix key words first.
554 			 *
555 			 * XXX
556 			 * Older versions of man.conf didn't have the suffix
557 			 * key words, it was assumed that everything was a .0.
558 			 * We just test for .0 first, it's fast and probably
559 			 * going to hit.
560 			 */
561 			(void)snprintf(buf, sizeof(buf), "*/%s.0", escpage);
562 			if (!fnmatch(buf, pg->gl_pathv[cnt], 0))
563 				goto next;
564 
565 			found = 0;
566 			TAILQ_FOREACH(suffix, &mp->suffixlist->entrylist, q) {
567 				(void)snprintf(buf,
568 				     sizeof(buf), "*/%s%s", escpage,
569 				     suffix->s);
570 				if (!fnmatch(buf, pg->gl_pathv[cnt], 0)) {
571 					found = 1;
572 					break;
573 				}
574 			}
575 			if (found)
576 				goto next;
577 
578 			/* Try the _build key words next. */
579 			found = 0;
580 			TAILQ_FOREACH(suffix, &mp->buildlist->entrylist, q) {
581 				for (p = suffix->s;
582 				    *p != '\0' && !isspace((unsigned char)*p);
583 				    ++p)
584 					continue;
585 				if (*p == '\0')
586 					continue;
587 				*p = '\0';
588 				(void)snprintf(buf,
589 				     sizeof(buf), "*/%s%s", escpage,
590 				     suffix->s);
591 				if (!fnmatch(buf, pg->gl_pathv[cnt], 0)) {
592 					if (!mp->where)
593 						build_page(p + 1,
594 						    &pg->gl_pathv[cnt], mp);
595 					*p = ' ';
596 					found = 1;
597 					break;
598 				}
599 				*p = ' ';
600 			}
601 			if (found) {
602 next:				anyfound = 1;
603 				if (!mp->all) {
604 					/* Delete any other matches. */
605 					while (++cnt< pg->gl_pathc)
606 						pg->gl_pathv[cnt] = "";
607 					break;
608 				}
609 				continue;
610 			}
611 
612 			/* It's not a man page, forget about it. */
613 			pg->gl_pathv[cnt] = "";
614 		}
615 
616 		if (anyfound && !mp->all)
617 			break;
618 	}
619 
620 	/* If not found, enter onto the missing list. */
621 	if (!anyfound) {
622 		if (addentry(mp->missinglist, page, 0) < 0) {
623 			warn("malloc");
624 			(void)cleanup();
625 			exit(1);
626 		}
627 	}
628 
629 	free(escpage);
630 	return (anyfound);
631 }
632 
633 /*
634  * build_page --
635  *	Build a man page for display.
636  */
637 static void
638 build_page(char *fmt, char **pathp, struct manstate *mp)
639 {
640 	static int warned;
641 	int olddir, fd, n, tmpdirlen;
642 	char *p, *b;
643 	char buf[MAXPATHLEN], cmd[MAXPATHLEN], tpath[MAXPATHLEN];
644 	const char *tmpdir;
645 
646 	/* Let the user know this may take awhile. */
647 	if (!warned) {
648 		warned = 1;
649 		warnx("Formatting manual page...");
650 	}
651 
652        /*
653         * Historically man chdir'd to the root of the man tree.
654         * This was used in man pages that contained relative ".so"
655         * directives (including other man pages for command aliases etc.)
656         * It even went one step farther, by examining the first line
657         * of the man page and parsing the .so filename so it would
658         * make hard(?) links to the cat'ted man pages for space savings.
659         * (We don't do that here, but we could).
660         */
661 
662        /* copy and find the end */
663        for (b = buf, p = *pathp; (*b++ = *p++) != '\0';)
664                continue;
665 
666 	/*
667 	 * skip the last two path components, page name and man[n] ...
668 	 * (e.g. buf will be "/usr/share/man" and p will be "man1/man.1")
669 	 * we also save a pointer to our current directory so that we
670 	 * can fchdir() back to it.  this allows relative MANDIR paths
671 	 * to work with multiple man pages... e.g. consider:
672 	 *   	cd /usr/share && man -M ./man cat ls
673 	 * when no "cat1" subdir files are present.
674 	 */
675 	olddir = -1;
676 	for (--b, --p, n = 2; b != buf; b--, p--)
677 		if (*b == '/')
678 			if (--n == 0) {
679 				*b = '\0';
680 				olddir = open(".", O_RDONLY);
681 				(void) chdir(buf);
682 				p++;
683 				break;
684 			}
685 
686 
687 	/* advance fmt pass the suffix spec to the printf format string */
688 	for (; *fmt && isspace((unsigned char)*fmt); ++fmt)
689 		continue;
690 
691 	/*
692 	 * Get a temporary file and build a version of the file
693 	 * to display.  Replace the old file name with the new one.
694 	 */
695 	if ((tmpdir = getenv("TMPDIR")) == NULL)
696 		tmpdir = _PATH_TMP;
697 	tmpdirlen = strlen(tmpdir);
698 	(void)snprintf(tpath, sizeof (tpath), "%s%s%s", tmpdir,
699 	    (tmpdirlen && tmpdir[tmpdirlen-1] == '/') ? "" : "/", TMPFILE);
700 	if ((fd = mkstemp(tpath)) == -1) {
701 		warn("%s", tpath);
702 		(void)cleanup();
703 		exit(1);
704 	}
705 	(void)snprintf(buf, sizeof(buf), "%s > %s", fmt, tpath);
706 	(void)snprintf(cmd, sizeof(cmd), buf, p);
707 	(void)system(cmd);
708 	(void)close(fd);
709 	if ((*pathp = strdup(tpath)) == NULL) {
710 		warn("malloc");
711 		(void)cleanup();
712 		exit(1);
713 	}
714 
715 	/* Link the built file into the remove-when-done list. */
716 	if (addentry(mp->intmp, *pathp, 0) < 0) {
717 		warn("malloc");
718 		(void)cleanup();
719 		exit(1);
720 	}
721 
722 	/* restore old directory so relative manpaths still work */
723 	if (olddir != -1) {
724 		fchdir(olddir);
725 		close(olddir);
726 	}
727 }
728 
729 /*
730  * how --
731  *	display how information
732  */
733 static void
734 how(char *fname)
735 {
736 	FILE *fp;
737 
738 	int lcnt, print;
739 	char *p, buf[256];
740 
741 	if (!(fp = fopen(fname, "r"))) {
742 		warn("%s", fname);
743 		(void)cleanup();
744 		exit (1);
745 	}
746 #define	S1	"SYNOPSIS"
747 #define	S2	"S\bSY\bYN\bNO\bOP\bPS\bSI\bIS\bS"
748 #define	D1	"DESCRIPTION"
749 #define	D2	"D\bDE\bES\bSC\bCR\bRI\bIP\bPT\bTI\bIO\bON\bN"
750 	for (lcnt = print = 0; fgets(buf, sizeof(buf), fp);) {
751 		if (!strncmp(buf, S1, sizeof(S1) - 1) ||
752 		    !strncmp(buf, S2, sizeof(S2) - 1)) {
753 			print = 1;
754 			continue;
755 		} else if (!strncmp(buf, D1, sizeof(D1) - 1) ||
756 		    !strncmp(buf, D2, sizeof(D2) - 1)) {
757 			if (fp)
758 				(void)fclose(fp);
759 			return;
760 		}
761 		if (!print)
762 			continue;
763 		if (*buf == '\n')
764 			++lcnt;
765 		else {
766 			for(; lcnt; --lcnt)
767 				(void)putchar('\n');
768 			for (p = buf; isspace((unsigned char)*p); ++p)
769 				continue;
770 			(void)fputs(p, stdout);
771 		}
772 	}
773 	(void)fclose(fp);
774 }
775 
776 /*
777  * cat --
778  *	cat out the file
779  */
780 static void
781 cat(char *fname)
782 {
783 	int fd, n;
784 	char buf[2048];
785 
786 	if ((fd = open(fname, O_RDONLY, 0)) < 0) {
787 		warn("%s", fname);
788 		(void)cleanup();
789 		exit(1);
790 	}
791 	while ((n = read(fd, buf, sizeof(buf))) > 0)
792 		if (write(STDOUT_FILENO, buf, n) != n) {
793 			warn("write");
794 			(void)cleanup();
795 			exit (1);
796 		}
797 	if (n == -1) {
798 		warn("read");
799 		(void)cleanup();
800 		exit(1);
801 	}
802 	(void)close(fd);
803 }
804 
805 /*
806  * check_pager --
807  *	check the user supplied page information
808  */
809 static const char *
810 check_pager(const char *name)
811 {
812 	const char *p;
813 
814 	/*
815 	 * if the user uses "more", we make it "more -s"; watch out for
816 	 * PAGER = "mypager /usr/ucb/more"
817 	 */
818 	for (p = name; *p && !isspace((unsigned char)*p); ++p)
819 		continue;
820 	for (; p > name && *p != '/'; --p);
821 	if (p != name)
822 		++p;
823 
824 	/* make sure it's "more", not "morex" */
825 	if (!strncmp(p, "more", 4) && (!p[4] || isspace((unsigned char)p[4]))){
826 		char *newname;
827 		(void)asprintf(&newname, "%s %s", p, "-s");
828 		name = newname;
829 	}
830 
831 	return (name);
832 }
833 
834 /*
835  * jump --
836  *	strip out flag argument and jump
837  */
838 static void
839 jump(char **argv, char *flag, char *name)
840 {
841 	char **arg;
842 
843 	argv[0] = name;
844 	for (arg = argv + 1; *arg; ++arg)
845 		if (!strcmp(*arg, flag))
846 			break;
847 	for (; *arg; ++arg)
848 		arg[0] = arg[1];
849 	execvp(name, argv);
850 	(void)fprintf(stderr, "%s: Command not found.\n", name);
851 	exit(1);
852 }
853 
854 /*
855  * onsig --
856  *	If signaled, delete the temporary files.
857  */
858 static void
859 onsig(int signo)
860 {
861 	sigset_t set;
862 
863 	(void)cleanup();
864 
865 	(void)signal(signo, SIG_DFL);
866 
867 	/* unblock the signal */
868 	sigemptyset(&set);
869 	sigaddset(&set, signo);
870 	sigprocmask(SIG_UNBLOCK, &set, (sigset_t *) NULL);
871 
872 	(void)kill(getpid(), signo);
873 
874 	/* NOTREACHED */
875 	exit (1);
876 }
877 
878 /*
879  * cleanup --
880  *	Clean up temporary files, show any error messages.
881  */
882 static int
883 cleanup()
884 {
885 	TAG *intmpp, *missp;
886 	ENTRY *ep;
887 	int rval;
888 
889 	rval = 0;
890 	/*
891 	 * note that _missing and _intmp were created by main(), so
892 	 * gettag() cannot return NULL here.
893 	 */
894 	missp = gettag("_missing", 0);	/* missing man pages */
895 	intmpp = gettag("_intmp", 0);	/* tmp files we need to unlink */
896 
897 	TAILQ_FOREACH(ep, &missp->entrylist, q) {
898 		warnx("no entry for %s in the manual.", ep->s);
899 		rval = 1;
900 	}
901 
902 	TAILQ_FOREACH(ep, &intmpp->entrylist, q)
903 		(void)unlink(ep->s);
904 
905 	return (rval);
906 }
907 
908 /*
909  * usage --
910  *	print usage message and die
911  */
912 static void
913 usage()
914 {
915 	(void)fprintf(stderr, "usage: %s [-acw|-h] [-C cfg] [-M path] "
916 	    "[-m path] [-S srch] [[-s] sect] name ...\n", getprogname());
917 	(void)fprintf(stderr,
918 	    "usage: %s -k [-C cfg] [-M path] [-m path] keyword ...\n",
919 	    getprogname());
920 	exit(1);
921 }
922