writeisofs: improve compatibility

[minix3.git] / usr.bin / man / man.c

/*      $NetBSD: man.c,v 1.41 2010/07/07 21:24:34 christos Exp $        */

/*
 * Copyright (c) 1987, 1993, 1994, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>

#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1987, 1993, 1994, 1995\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)man.c       8.17 (Berkeley) 1/31/95";
#else
__RCSID("$NetBSD: man.c,v 1.41 2010/07/07 21:24:34 christos Exp $");
#endif
#endif /* not lint */

#include <sys/param.h>
#include <sys/queue.h>
#include <sys/utsname.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <glob.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <util.h>
#include <locale.h>

#include "manconf.h"
#include "pathnames.h"

#ifndef MAN_DEBUG
#define MAN_DEBUG 0             /* debug path output */
#endif

/*
 * manstate: structure collecting the current global state so we can 
 * easily identify it and pass it to helper functions in one arg.
 */
struct manstate {
        /* command line flags */
        int all;                /* -a: show all matches rather than first */
        int cat;                /* -c: do not use a pager */
        char *conffile;         /* -C: use alternate config file */
        int how;                /* -h: show SYNOPSIS only */
        char *manpath;          /* -M: alternate MANPATH */
        char *addpath;          /* -m: add these dirs to front of manpath */
        char *pathsearch;       /* -S: path of man must contain this string */
        char *sectionname;      /* -s: limit search to a given man section */
        int where;              /* -w: just show paths of all matching files */

        /* important tags from the config file */
        TAG *defaultpath;       /* _default: default MANPATH */
        TAG *subdirs;           /* _subdir: default subdir search list */
        TAG *suffixlist;        /* _suffix: for files that can be cat()'d */
        TAG *buildlist;         /* _build: for files that must be built */
        
        /* tags for internal use */
        TAG *intmp;             /* _intmp: tmp files we must cleanup */
        TAG *missinglist;       /* _missing: pages we couldn't find */
        TAG *mymanpath;         /* _new_path: final version of MANPATH */
        TAG *section;           /* <sec>: tag for m.sectionname */

        /* other misc stuff */
        const char *pager;      /* pager to use */
        const char *machine;    /* machine */
        const char *machclass;  /* machine class */
        size_t pagerlen;        /* length of the above */
};

/*
 * prototypes
 */
static void      build_page(char *, char **, struct manstate *);
static void      cat(char *);
static const char       *check_pager(const char *);
static int       cleanup(void);
static void      how(char *);
static void      jump(char **, char *, char *);
static int       manual(char *, struct manstate *, glob_t *);
static void      onsig(int);
static void      usage(void) __attribute__((__noreturn__));
static void      addpath(struct manstate *, const char *, size_t, const char *);
static const char *getclass(const char *);

/*
 * main function
 */
int
main(int argc, char **argv)
{
        static struct manstate m = { 0 };       /* init to zero */
        int ch, abs_section, found;
        ENTRY *esubd, *epath;
        char *p, **ap, *cmd;
        size_t len;
        glob_t pg;

        setprogname(argv[0]);
        setlocale(LC_ALL, "");
        /*
         * parse command line...
         */
        while ((ch = getopt(argc, argv, "-aC:cfhkM:m:P:s:S:w")) != -1)
                switch (ch) {
                case 'a':
                        m.all = 1;
                        break;
                case 'C':
                        m.conffile = optarg;
                        break;
                case 'c':
                case '-':       /* XXX: '-' is a deprecated version of '-c' */
                        m.cat = 1;
                        break;
                case 'h':
                        m.how = 1;
                        break;
                case 'm':
                        m.addpath = optarg;
                        break;
                case 'M':
                case 'P':       /* -P for backward compatibility */
                        m.manpath = strdup(optarg);
                        break;
                /*
                 * The -f and -k options are backward compatible,
                 * undocumented ways of calling whatis(1) and apropos(1).
                 */
                case 'f':
                        jump(argv, "-f", "whatis");
                        /* NOTREACHED */
                case 'k':
                        jump(argv, "-k", "apropos");
                        /* NOTREACHED */
                case 's':
                        if (m.sectionname != NULL)
                                usage();
                        m.sectionname = optarg;
                        break;
                case 'S':
                        m.pathsearch = optarg;
                        break;
                case 'w':
                        m.all = m.where = 1;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (!argc)
                usage();

        /*
         * read the configuration file and collect any other information
         * we will need (machine type, pager, section [if specified
         * without '-s'], and MANPATH through the environment).
         */
        config(m.conffile);    /* exits on error ... */

        if ((m.machine = getenv("MACHINE")) == NULL) {
                struct utsname utsname;

                if (uname(&utsname) == -1)
                        err(EXIT_FAILURE, "uname");
                m.machine = utsname.machine;
        }

        m.machclass = getclass(m.machine);

        if (!m.cat && !m.how && !m.where) {  /* if we need a pager ... */
                if (!isatty(STDOUT_FILENO)) {
                        m.cat = 1;
                } else {
                        if ((m.pager = getenv("PAGER")) != NULL &&
                            m.pager[0] != '\0')
                                m.pager = check_pager(m.pager);
                        else
                                m.pager = _PATH_PAGER;
                        m.pagerlen = strlen(m.pager);
                }
        }

        /* do we need to set m.section to a non-null value? */
        if (m.sectionname) {

                m.section = gettag(m.sectionname, 0); /* -s must be a section */
                if (m.section == NULL)
                        errx(EXIT_FAILURE, "unknown section: %s", m.sectionname);

        } else if (argc > 1) {

                m.section = gettag(*argv, 0);  /* might be a section? */
                if (m.section) {
                        argv++;
                        argc--;
                }

        } 
        
        if (m.manpath == NULL)
                m.manpath = getenv("MANPATH"); /* note: -M overrides getenv */


        /*
         * get default values from config file, plus create the tags we
         * use for keeping internal state.  make sure all our mallocs
         * go through.
         */
        /* from cfg file */
        m.defaultpath = gettag("_default", 1);
        m.subdirs = gettag("_subdir", 1);
        m.suffixlist = gettag("_suffix", 1);
        m.buildlist = gettag("_build", 1); 
        /* internal use */
        m.mymanpath = gettag("_new_path", 1);
        m.missinglist = gettag("_missing", 1);
        m.intmp = gettag("_intmp", 1);
        if (!m.defaultpath || !m.subdirs || !m.suffixlist || !m.buildlist ||
            !m.mymanpath || !m.missinglist || !m.intmp)
                errx(EXIT_FAILURE, "malloc failed");

        /*
         * are we using a section whose elements are all absolute paths?
         * (we only need to look at the first entry on the section list,
         * as config() will ensure that any additional entries will match
         * the first one.)
         */
        abs_section = (m.section != NULL && 
                !TAILQ_EMPTY(&m.section->entrylist) &&
                        *(TAILQ_FIRST(&m.section->entrylist)->s) == '/');

        /*
         * now that we have all the data we need, we must determine the
         * manpath we are going to use to find the requested entries using
         * the following steps...
         *
         * [1] if the user specified a section and that section's elements
         *     from the config file are all absolute paths, then we override
         *     defaultpath and -M/MANPATH with the section's absolute paths.
         */
        if (abs_section) {
                m.manpath = NULL;               /* ignore -M/MANPATH */
                m.defaultpath = m.section;      /* overwrite _default path */
                m.section = NULL;               /* promoted to defaultpath */
        }

        /*
         * [2] section can now only be non-null if the user asked for
         *     a section and that section's elements did not have 
         *     absolute paths.  in this case we use the section's
         *     elements to override _subdir from the config file.
         *
         * after this step, we are done processing "m.section"...
         */
        if (m.section)
                m.subdirs = m.section;

        /*
         * [3] we need to setup the path we want to use (m.mymanpath).
         *     if the user gave us a path (m.manpath) use it, otherwise
         *     go with the default.   in either case we need to append
         *     the subdir and machine spec to each element of the path.
         *
         *     for absolute section paths that come from the config file, 
         *     we only append the subdir spec if the path ends in 
         *     a '/' --- elements that do not end in '/' are assumed to 
         *     not have subdirectories.  this is mainly for backward compat, 
         *     but it allows non-subdir configs like:
         *      sect3       /usr/share/man/{old/,}cat3
         *      doc         /usr/{pkg,share}/doc/{sendmail/op,sendmail/intro}
         *
         *     note that we try and be careful to not put double slashes
         *     in the path (e.g. we want /usr/share/man/man1, not
         *     /usr/share/man//man1) because "more" will put the filename
         *     we generate in its prompt and the double slashes look ugly.
         */
        if (m.manpath) {

                /* note: strtok is going to destroy m.manpath */
                for (p = strtok(m.manpath, ":") ; p ; p = strtok(NULL, ":")) {
                        len = strlen(p);
                        if (len < 1)
                                continue;
                        TAILQ_FOREACH(esubd, &m.subdirs->entrylist, q)
                                addpath(&m, p, len, esubd->s);
                }

        } else {

                TAILQ_FOREACH(epath, &m.defaultpath->entrylist, q) {
                        /* handle trailing "/" magic here ... */
                        if (abs_section && epath->s[epath->len - 1] != '/') {
                                addpath(&m, "", 1, epath->s);
                                continue;
                        }

                        TAILQ_FOREACH(esubd, &m.subdirs->entrylist, q)
                                addpath(&m, epath->s, epath->len, esubd->s);
                }

        }

        /*
         * [4] finally, prepend the "-m" m.addpath to mymanpath if it 
         *     was specified.   subdirs and machine are always applied to
         *     m.addpath. 
         */
        if (m.addpath) {

                /* note: strtok is going to destroy m.addpath */
                for (p = strtok(m.addpath, ":") ; p ; p = strtok(NULL, ":")) {
                        len = strlen(p);
                        if (len < 1)
                                continue;
                        TAILQ_FOREACH(esubd, &m.subdirs->entrylist, q)
                                addpath(&m, p, len, esubd->s);
                }

        }

        /*
         * now m.mymanpath is complete!
         */
#if MAN_DEBUG
        printf("mymanpath:\n");
        TAILQ_FOREACH(epath, &m.mymanpath->entrylist, q) {
                printf("\t%s\n", epath->s);
        }
#endif

        /*
         * start searching for matching files and format them if necessary.   
         * setup an interrupt handler so that we can ensure that temporary 
         * files go away.
         */
        (void)signal(SIGINT, onsig);
        (void)signal(SIGHUP, onsig);
        (void)signal(SIGPIPE, onsig);

        memset(&pg, 0, sizeof(pg));
        for (found = 0; *argv; ++argv)
                if (manual(*argv, &m, &pg)) {
                        found = 1;
                }

        /* if nothing found, we're done. */
        if (!found) {
                (void)cleanup();
                exit(EXIT_FAILURE);
        }

        /*
         * handle the simple display cases first (m.cat, m.how, m.where)
         */
        if (m.cat) {
                for (ap = pg.gl_pathv; *ap != NULL; ++ap) {
                        if (**ap == '\0')
                                continue;
                        cat(*ap);
                }
                exit(cleanup());
        }
        if (m.how) {
                for (ap = pg.gl_pathv; *ap != NULL; ++ap) {
                        if (**ap == '\0')
                                continue;
                        how(*ap);
                }
                exit(cleanup());
        }
        if (m.where) {
                for (ap = pg.gl_pathv; *ap != NULL; ++ap) {
                        if (**ap == '\0')
                                continue;
                        (void)printf("%s\n", *ap);
                }
                exit(cleanup());
        }
                
        /*
         * normal case - we display things in a single command, so
         * build a list of things to display.  first compute total
         * length of buffer we will need so we can malloc it.
         */
        for (ap = pg.gl_pathv, len = m.pagerlen + 1; *ap != NULL; ++ap) {
                if (**ap == '\0')
                        continue;
                len += strlen(*ap) + 1;
        }
        if ((cmd = malloc(len)) == NULL) {
                warn("malloc");
                (void)cleanup();
                exit(EXIT_FAILURE);
        }

        /* now build the command string... */
        p = cmd;
        len = m.pagerlen;
        memcpy(p, m.pager, len);
        p += len;
        *p++ = ' ';
        for (ap = pg.gl_pathv; *ap != NULL; ++ap) {
                if (**ap == '\0')
                        continue;
                len = strlen(*ap);
                memcpy(p, *ap, len);
                p += len;
                *p++ = ' ';
        }
        *--p = '\0';

        /* Use system(3) in case someone's pager is "pager arg1 arg2". */
        (void)system(cmd);

        exit(cleanup());
}

static int
manual_find_buildkeyword(char *escpage, const char *fmt,
        struct manstate *mp, glob_t *pg, size_t cnt)
{
        ENTRY *suffix;
        int found;
        char *p, buf[MAXPATHLEN];

        found = 0;
        /* Try the _build key words next. */
        TAILQ_FOREACH(suffix, &mp->buildlist->entrylist, q) {
                for (p = suffix->s;
                    *p != '\0' && !isspace((unsigned char)*p);
                    ++p)
                        continue;
                if (*p == '\0')
                        continue;

                *p = '\0';
                (void)snprintf(buf, sizeof(buf), fmt, escpage, suffix->s);
                if (!fnmatch(buf, pg->gl_pathv[cnt], 0)) {
                        if (!mp->where)
                                build_page(p + 1, &pg->gl_pathv[cnt], mp);
                        *p = ' ';
                        found = 1;
                        break;
                }      
                *p = ' ';
        }

        return found;
}

/*
 * manual --
 *      Search the manuals for the pages.
 */
static int
manual(char *page, struct manstate *mp, glob_t *pg)
{
        ENTRY *suffix, *mdir;
        int anyfound, error, found;
        size_t cnt;
        char *p, buf[MAXPATHLEN], *escpage, *eptr;
        static const char escglob[] = "\\~?*{}[]";

        anyfound = 0;

        /*
         * Fixup page which may contain glob(3) special characters, e.g.
         * the famous "No man page for [" FAQ.
         */
        if ((escpage = malloc((2 * strlen(page)) + 1)) == NULL) {
                warn("malloc");
                (void)cleanup();
                exit(EXIT_FAILURE);
        }

        p = page;
        eptr = escpage;

        while (*p) {
                if (strchr(escglob, *p) != NULL) {
                        *eptr++ = '\\';
                        *eptr++ = *p++;
                } else
                        *eptr++ = *p++;
        }

        *eptr = '\0';

        /*
         * If 'page' is given with a full or relative path
         * then interpret it as a file specification.
         */
        if ((page[0] == '/') || (page[0] == '.')) {
                /* check if file actually exists */
                (void)strlcpy(buf, escpage, sizeof(buf));
                error = glob(buf, GLOB_APPEND | GLOB_BRACE | GLOB_NOSORT, NULL, pg);
                if (error != 0) {
                        if (error == GLOB_NOMATCH) {
                                goto notfound;
                        } else {
                                errx(EXIT_FAILURE, "glob failed");
                        }
                }

                if (pg->gl_matchc == 0)
                        goto notfound;

                /* clip suffix for the suffix check below */
                p = strrchr(escpage, '.');
                if (p && p[0] == '.' && isdigit((unsigned char)p[1]))
                        p[0] = '\0';

                found = 0;
                for (cnt = pg->gl_pathc - pg->gl_matchc;
                    cnt < pg->gl_pathc; ++cnt)
                {
                        found = manual_find_buildkeyword(escpage, "%s%s",
                                mp, pg, cnt);
                        if (found) {
                                anyfound = 1;
                                if (!mp->all) {
                                        /* Delete any other matches. */
                                        while (++cnt< pg->gl_pathc)
                                                pg->gl_pathv[cnt] = "";
                                        break;
                                }
                                continue;
                        }

                        /* It's not a man page, forget about it. */
                        pg->gl_pathv[cnt] = "";
                }

  notfound:
                if (!anyfound) {
                        if (addentry(mp->missinglist, page, 0) < 0) {
                                warn("malloc");
                                (void)cleanup();
                                exit(EXIT_FAILURE);
                        }
                }
                free(escpage);
                return anyfound;
        }

        /* For each man directory in mymanpath ... */
        TAILQ_FOREACH(mdir, &mp->mymanpath->entrylist, q) {

                /* 
                 * use glob(3) to look in the filesystem for matching files.
                 * match any suffix here, as we will check that later.
                 */
                (void)snprintf(buf, sizeof(buf), "%s/%s.*", mdir->s, escpage);
                if ((error = glob(buf,
                    GLOB_APPEND | GLOB_BRACE | GLOB_NOSORT, NULL, pg)) != 0) {
                        if (error == GLOB_NOMATCH)
                                continue;
                        else {
                                warn("globbing");
                                (void)cleanup();
                                exit(EXIT_FAILURE);
                        }
                }
                if (pg->gl_matchc == 0)
                        continue;

                /*
                 * start going through the matches glob(3) just found and 
                 * use m.pathsearch (if present) to filter out pages we 
                 * don't want.  then verify the suffix is valid, and build
                 * the page if we have a _build suffix.
                 */
                for (cnt = pg->gl_pathc - pg->gl_matchc;
                    cnt < pg->gl_pathc; ++cnt) {

                        /* filter on directory path name */
                        if (mp->pathsearch) {
                                p = strstr(pg->gl_pathv[cnt], mp->pathsearch);
                                if (!p || strchr(p, '/') == NULL) {
                                        pg->gl_pathv[cnt] = ""; /* zap! */
                                        continue;
                                }
                        }

                        /*
                         * Try the _suffix key words first.
                         *
                         * XXX
                         * Older versions of man.conf didn't have the suffix
                         * key words, it was assumed that everything was a .0.
                         * We just test for .0 first, it's fast and probably
                         * going to hit.
                         */
                        (void)snprintf(buf, sizeof(buf), "*/%s.0", escpage);
                        if (!fnmatch(buf, pg->gl_pathv[cnt], 0))
                                goto next;

                        found = 0;
                        TAILQ_FOREACH(suffix, &mp->suffixlist->entrylist, q) {
                                (void)snprintf(buf,
                                     sizeof(buf), "*/%s%s", escpage,
                                     suffix->s);
                                if (!fnmatch(buf, pg->gl_pathv[cnt], 0)) {
                                        found = 1;
                                        break;
                                }
                        }
                        if (found)
                                goto next;

                        /* Try the _build key words next. */
                        found = manual_find_buildkeyword(escpage, "*/%s%s",
                                mp, pg, cnt);
                        if (found) {
next:                           anyfound = 1;
                                if (!mp->all) {
                                        /* Delete any other matches. */
                                        while (++cnt< pg->gl_pathc)
                                                pg->gl_pathv[cnt] = "";
                                        break;
                                }
                                continue;
                        }

                        /* It's not a man page, forget about it. */
                        pg->gl_pathv[cnt] = "";
                }

                if (anyfound && !mp->all)
                        break;
        }

        /* If not found, enter onto the missing list. */
        if (!anyfound) {
                if (addentry(mp->missinglist, page, 0) < 0) {
                        warn("malloc");
                        (void)cleanup();
                        exit(EXIT_FAILURE);
                }
        }

        free(escpage);
        return anyfound;
}

/* 
 * build_page --
 *      Build a man page for display.
 */
static void
build_page(char *fmt, char **pathp, struct manstate *mp)
{
        static int warned;
        int olddir, fd, n, tmpdirlen;
        char *p, *b;
        char buf[MAXPATHLEN], cmd[MAXPATHLEN], tpath[MAXPATHLEN];
        const char *tmpdir;

        /* Let the user know this may take awhile. */
        if (!warned) {
                warned = 1;
                warnx("Formatting manual page...");
        }

       /*
        * Historically man chdir'd to the root of the man tree. 
        * This was used in man pages that contained relative ".so"
        * directives (including other man pages for command aliases etc.)
        * It even went one step farther, by examining the first line
        * of the man page and parsing the .so filename so it would
        * make hard(?) links to the cat'ted man pages for space savings.
        * (We don't do that here, but we could).
        */
 
       /* copy and find the end */
       for (b = buf, p = *pathp; (*b++ = *p++) != '\0';)
               continue;
 
        /* 
         * skip the last two path components, page name and man[n] ...
         * (e.g. buf will be "/usr/share/man" and p will be "man1/man.1")
         * we also save a pointer to our current directory so that we
         * can fchdir() back to it.  this allows relative MANDIR paths
         * to work with multiple man pages... e.g. consider:
         *      cd /usr/share && man -M ./man cat ls
         * when no "cat1" subdir files are present.
         */
        olddir = -1;
        for (--b, --p, n = 2; b != buf; b--, p--)
                if (*b == '/')
                        if (--n == 0) {
                                *b = '\0';
                                olddir = open(".", O_RDONLY);
                                (void) chdir(buf);
                                p++;
                                break;
                        }


        /* advance fmt pass the suffix spec to the printf format string */
        for (; *fmt && isspace((unsigned char)*fmt); ++fmt)
                continue;

        /*
         * Get a temporary file and build a version of the file
         * to display.  Replace the old file name with the new one.
         */
        if ((tmpdir = getenv("TMPDIR")) == NULL)
                tmpdir = _PATH_TMP;
        tmpdirlen = strlen(tmpdir);
        (void)snprintf(tpath, sizeof (tpath), "%s%s%s", tmpdir, 
            (tmpdirlen && tmpdir[tmpdirlen-1] == '/') ? "" : "/", TMPFILE);
        if ((fd = mkstemp(tpath)) == -1) {
                warn("%s", tpath);
                (void)cleanup();
                exit(EXIT_FAILURE);
        }
        (void)snprintf(buf, sizeof(buf), "%s > %s", fmt, tpath);
        (void)snprintf(cmd, sizeof(cmd), buf, p);
        (void)system(cmd);
        (void)close(fd);
        if ((*pathp = strdup(tpath)) == NULL) {
                warn("malloc");
                (void)cleanup();
                exit(EXIT_FAILURE);
        }

        /* Link the built file into the remove-when-done list. */
        if (addentry(mp->intmp, *pathp, 0) < 0) {
                warn("malloc");
                (void)cleanup();
                exit(EXIT_FAILURE);
        }

        /* restore old directory so relative manpaths still work */
        if (olddir != -1) {
                fchdir(olddir);
                close(olddir);
        }
}

/*
 * how --
 *      display how information
 */
static void
how(char *fname)
{
        FILE *fp;

        int lcnt, print;
        char *p, buf[256];

        if (!(fp = fopen(fname, "r"))) {
                warn("%s", fname);
                (void)cleanup();
                exit(EXIT_FAILURE);
        }
#define S1      "SYNOPSIS"
#define S2      "S\bSY\bYN\bNO\bOP\bPS\bSI\bIS\bS"
#define D1      "DESCRIPTION"
#define D2      "D\bDE\bES\bSC\bCR\bRI\bIP\bPT\bTI\bIO\bON\bN"
        for (lcnt = print = 0; fgets(buf, sizeof(buf), fp);) {
                if (!strncmp(buf, S1, sizeof(S1) - 1) ||
                    !strncmp(buf, S2, sizeof(S2) - 1)) {
                        print = 1;
                        continue;
                } else if (!strncmp(buf, D1, sizeof(D1) - 1) ||
                    !strncmp(buf, D2, sizeof(D2) - 1)) {
                        if (fp)
                                (void)fclose(fp);
                        return;
                }
                if (!print)
                        continue;
                if (*buf == '\n')
                        ++lcnt;
                else {
                        for(; lcnt; --lcnt)
                                (void)putchar('\n');
                        for (p = buf; isspace((unsigned char)*p); ++p)
                                continue;
                        (void)fputs(p, stdout);
                }
        }
        (void)fclose(fp);
}

/*
 * cat --
 *      cat out the file
 */
static void
cat(char *fname)
{
        int fd, n;
        char buf[2048];

        if ((fd = open(fname, O_RDONLY, 0)) < 0) {
                warn("%s", fname);
                (void)cleanup();
                exit(EXIT_FAILURE);
        }
        while ((n = read(fd, buf, sizeof(buf))) > 0)
                if (write(STDOUT_FILENO, buf, n) != n) {
                        warn("write");
                        (void)cleanup();
                        exit(EXIT_FAILURE);
                }
        if (n == -1) {
                warn("read");
                (void)cleanup();
                exit(EXIT_FAILURE);
        }
        (void)close(fd);
}

/*
 * check_pager --
 *      check the user supplied page information
 */
static const char *
check_pager(const char *name)
{
        const char *p;

        /*
         * if the user uses "more", we make it "more -s"; watch out for
         * PAGER = "mypager /usr/ucb/more"
         */
        for (p = name; *p && !isspace((unsigned char)*p); ++p)
                continue;
        for (; p > name && *p != '/'; --p);
        if (p != name)
                ++p;

        /* make sure it's "more", not "morex" */
        if (!strncmp(p, "more", 4) && (!p[4] || isspace((unsigned char)p[4]))){
                char *newname;
                (void)asprintf(&newname, "%s %s", p, "-s");
                name = newname;
        }

        return name;
}

/*
 * jump --
 *      strip out flag argument and jump
 */
static void
jump(char **argv, char *flag, char *name)
{
        char **arg;

        argv[0] = name;
        for (arg = argv + 1; *arg; ++arg)
                if (!strcmp(*arg, flag))
                        break;
        for (; *arg; ++arg)
                arg[0] = arg[1];
        execvp(name, argv);
        err(EXIT_FAILURE, "Cannot execute `%s'", name);
}

/* 
 * onsig --
 *      If signaled, delete the temporary files.
 */
static void
onsig(int signo)
{

        (void)cleanup();

        (void)raise_default_signal(signo);

        /* NOTREACHED */
        exit(EXIT_FAILURE);
}

/*
 * cleanup --
 *      Clean up temporary files, show any error messages.
 */
static int
cleanup(void)
{
        TAG *intmpp, *missp;
        ENTRY *ep;
        int rval;

        rval = EXIT_SUCCESS;
        /* 
         * note that _missing and _intmp were created by main(), so
         * gettag() cannot return NULL here.
         */
        missp = gettag("_missing", 0);  /* missing man pages */
        intmpp = gettag("_intmp", 0);   /* tmp files we need to unlink */

        TAILQ_FOREACH(ep, &missp->entrylist, q) {
                warnx("no entry for %s in the manual.", ep->s);
                rval = EXIT_FAILURE;
        }

        TAILQ_FOREACH(ep, &intmpp->entrylist, q)
                (void)unlink(ep->s);

        return rval;
}

static const char *
getclass(const char *machine)
{
        char buf[BUFSIZ];
        TAG *t;
        snprintf(buf, sizeof(buf), "_%s", machine);
        t = gettag(buf, 0);
        return t != NULL && !TAILQ_EMPTY(&t->entrylist) ?
            TAILQ_FIRST(&t->entrylist)->s : NULL;
}

static void
addpath(struct manstate *m, const char *dir, size_t len, const char *sub)
{
        char buf[2 * MAXPATHLEN + 1];
        (void)snprintf(buf, sizeof(buf), "%s%s%s{/%s,%s%s%s}",
             dir, (dir[len - 1] == '/') ? "" : "/", sub, m->machine,
             m->machclass ? "/" : "", m->machclass ? m->machclass : "",
             m->machclass ? "," : "");
        if (addentry(m->mymanpath, buf, 0) < 0)
                errx(EXIT_FAILURE, "malloc failed");
}

/*
 * usage --
 *      print usage message and die
 */
static void
usage(void)
{
        (void)fprintf(stderr, "Usage: %s [-acw|-h] [-C cfg] [-M path] "
            "[-m path] [-S srch] [[-s] sect] name ...\n", getprogname());
        (void)fprintf(stderr, 
            "Usage: %s -k [-C cfg] [-M path] [-m path] keyword ...\n", 
            getprogname());
        exit(EXIT_FAILURE);
}