/* $OpenBSD: mandocdb.c,v 1.222 2025/06/05 12:32:27 schwarze Exp $ */
/*
 * Copyright (c) 2011-2021, 2024, 2025 Ingo Schwarze <schwarze@openbsd.org>
 * Copyright (c) 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2016 Ed Maste <emaste@freebsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Implementation of the makewhatis(8) program.
 */
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include <assert.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fts.h>
#include <limits.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "mandoc_aux.h"
#include "mandoc_ohash.h"
#include "mandoc.h"
#include "roff.h"
#include "mdoc.h"
#include "man.h"
#include "mandoc_parse.h"
#include "manconf.h"
#include "mansearch.h"
#include "dba_array.h"
#include "dba.h"

extern const char *const mansearch_keynames[];

enum    op {
        OP_DEFAULT = 0, /* new dbs from dir list or default config */
        OP_CONFFILE, /* new databases from custom config file */
        OP_UPDATE, /* delete/add entries in existing database */
        OP_DELETE, /* delete entries from existing database */
        OP_TEST /* change no databases, report potential problems */
};

struct  str {
        const struct mpage *mpage; /* if set, the owning parse */
        uint64_t         mask; /* bitmask in sequence */
        char             key[]; /* rendered text */
};

struct  inodev {
        ino_t            st_ino;
        dev_t            st_dev;
};

struct  mpage {
        struct inodev    inodev;  /* used for hashing routine */
        struct dba_array *dba;
        char            *sec;     /* section from file content */
        char            *arch;    /* architecture from file content */
        char            *title;   /* title from file content */
        char            *desc;    /* description from file content */
        struct mpage    *next;    /* singly linked list */
        struct mlink    *mlinks;  /* singly linked list */
        int              name_head_done;
        enum form        form;    /* format from file content */
};

struct  mlink {
        char             file[PATH_MAX]; /* filename rel. to manpath */
        char            *dsec;    /* section from directory */
        char            *arch;    /* architecture from directory */
        char            *name;    /* name from file name (not empty) */
        char            *fsec;    /* section from file name suffix */
        struct mlink    *next;    /* singly linked list */
        struct mpage    *mpage;   /* parent */
        int              gzip;    /* filename has a .gz suffix */
        enum form        dform;   /* format from directory */
        enum form        fform;   /* format from file name suffix */
};

typedef int (*mdoc_fp)(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);

struct  mdoc_handler {
        mdoc_fp          fp; /* optional handler */
        uint64_t         mask;  /* set unless handler returns 0 */
        int              taboo;  /* node flags that must not be set */
};


int              mandocdb(int, char *[]);

static  void     dbadd(struct dba *, struct mpage *);
static  void     dbadd_mlink(const struct mlink *);
static  void     dbprune(struct dba *);
static  void     dbwrite(struct dba *);
static  void     filescan(const char *);
static  int      fts_compare(const FTSENT **, const FTSENT **);
static  void     mlink_add(struct mlink *, const struct stat *);
static  void     mlink_check(struct mpage *, struct mlink *);
static  void     mlink_free(struct mlink *);
static  void     mlinks_undupe(struct mpage *);
static  void     mpages_free(void);
static  void     mpages_merge(struct dba *, struct mparse *);
static  void     parse_cat(struct mpage *, int);
static  void     parse_man(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  void     parse_mdoc(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  int      parse_mdoc_head(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  int      parse_mdoc_Fa(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  int      parse_mdoc_Fd(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  void     parse_mdoc_fname(struct mpage *, const struct roff_node *);
static  int      parse_mdoc_Fn(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  int      parse_mdoc_Fo(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  int      parse_mdoc_Lb(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  int      parse_mdoc_Nd(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  int      parse_mdoc_Nm(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  int      parse_mdoc_Sh(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  int      parse_mdoc_Va(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  int      parse_mdoc_Xr(struct mpage *, const struct roff_meta *,
                        const struct roff_node *);
static  void     putkey(const struct mpage *, char *, uint64_t);
static  void     putkeys(const struct mpage *, char *, size_t, uint64_t);
static  void     putmdockey(const struct mpage *,
                        const struct roff_node *, uint64_t, int);
static  int      render_string(char **, size_t *);
static  void     say(const char *, const char *, ...)
                        __attribute__((__format__ (__printf__, 2, 3)));
static  int      set_basedir(const char *, int);
static  int      treescan(void);
static  size_t   utf8(unsigned int, char[5]);

static  int              nodb; /* no database changes */
static  int              mparse_options; /* abort the parse early */
static  int              use_all; /* use all found files */
static  int              debug; /* print what we're doing */
static  int              warnings; /* warn about crap */
static  int              write_utf8; /* write UTF-8 output; else ASCII */
static  int              exitcode; /* to be returned by main */
static  enum op          op; /* operational mode */
static  char             basedir[PATH_MAX]; /* current base directory */
static  size_t           basedir_len; /* strlen(basedir) */
static  struct mpage    *mpage_head; /* list of distinct manual pages */
static  struct ohash     mpages; /* table of distinct manual pages */
static  struct ohash     mlinks; /* table of directory entries */
static  struct ohash     names; /* table of all names */
static  struct ohash     strings; /* table of all strings */
static  uint64_t         name_mask;

static  const struct mdoc_handler mdoc_handlers[MDOC_MAX - MDOC_Dd] = {
        { NULL, 0, NODE_NOPRT },  /* Dd */
        { NULL, 0, NODE_NOPRT },  /* Dt */
        { NULL, 0, NODE_NOPRT },  /* Os */
        { parse_mdoc_Sh, TYPE_Sh, 0 }, /* Sh */
        { parse_mdoc_head, TYPE_Ss, 0 }, /* Ss */
        { NULL, 0, 0 },  /* Pp */
        { NULL, 0, 0 },  /* D1 */
        { NULL, 0, 0 },  /* Dl */
        { NULL, 0, 0 },  /* Bd */
        { NULL, 0, 0 },  /* Ed */
        { NULL, 0, 0 },  /* Bl */
        { NULL, 0, 0 },  /* El */
        { NULL, 0, 0 },  /* It */
        { NULL, 0, 0 },  /* Ad */
        { NULL, TYPE_An, 0 },  /* An */
        { NULL, 0, 0 },  /* Ap */
        { NULL, TYPE_Ar, 0 },  /* Ar */
        { NULL, TYPE_Cd, 0 },  /* Cd */
        { NULL, TYPE_Cm, 0 },  /* Cm */
        { NULL, TYPE_Dv, 0 },  /* Dv */
        { NULL, TYPE_Er, 0 },  /* Er */
        { NULL, TYPE_Ev, 0 },  /* Ev */
        { NULL, 0, 0 },  /* Ex */
        { parse_mdoc_Fa, 0, 0 },  /* Fa */
        { parse_mdoc_Fd, 0, 0 },  /* Fd */
        { NULL, TYPE_Fl, 0 },  /* Fl */
        { parse_mdoc_Fn, 0, 0 },  /* Fn */
        { NULL, TYPE_Ft | TYPE_Vt, 0 },  /* Ft */
        { NULL, TYPE_Ic, 0 },  /* Ic */
        { NULL, TYPE_In, 0 },  /* In */
        { NULL, TYPE_Li, 0 },  /* Li */
        { parse_mdoc_Nd, 0, 0 },  /* Nd */
        { parse_mdoc_Nm, 0, 0 },  /* Nm */
        { NULL, 0, 0 },  /* Op */
        { NULL, 0, 0 },  /* Ot */
        { NULL, TYPE_Pa, NODE_NOSRC },  /* Pa */
        { NULL, 0, 0 },  /* Rv */
        { NULL, TYPE_St, 0 },  /* St */
        { parse_mdoc_Va, TYPE_Va, 0 },  /* Va */
        { parse_mdoc_Va, TYPE_Vt, 0 },  /* Vt */
        { parse_mdoc_Xr, 0, 0 },  /* Xr */
        { NULL, 0, 0 },  /* %A */
        { NULL, 0, 0 },  /* %B */
        { NULL, 0, 0 },  /* %D */
        { NULL, 0, 0 },  /* %I */
        { NULL, 0, 0 },  /* %J */
        { NULL, 0, 0 },  /* %N */
        { NULL, 0, 0 },  /* %O */
        { NULL, 0, 0 },  /* %P */
        { NULL, 0, 0 },  /* %R */
        { NULL, 0, 0 },  /* %T */
        { NULL, 0, 0 },  /* %V */
        { NULL, 0, 0 },  /* Ac */
        { NULL, 0, 0 },  /* Ao */
        { NULL, 0, 0 },  /* Aq */
        { NULL, TYPE_At, 0 },  /* At */
        { NULL, 0, 0 },  /* Bc */
        { NULL, 0, 0 },  /* Bf */
        { NULL, 0, 0 },  /* Bo */
        { NULL, 0, 0 },  /* Bq */
        { NULL, TYPE_Bsx, NODE_NOSRC },  /* Bsx */
        { NULL, TYPE_Bx, NODE_NOSRC },  /* Bx */
        { NULL, 0, 0 },  /* Db */
        { NULL, 0, 0 },  /* Dc */
        { NULL, 0, 0 },  /* Do */
        { NULL, 0, 0 },  /* Dq */
        { NULL, 0, 0 },  /* Ec */
        { NULL, 0, 0 },  /* Ef */
        { NULL, TYPE_Em, 0 },  /* Em */
        { NULL, 0, 0 },  /* Eo */
        { NULL, TYPE_Fx, NODE_NOSRC },  /* Fx */
        { NULL, TYPE_Ms, 0 },  /* Ms */
        { NULL, 0, 0 },  /* No */
        { NULL, 0, 0 },  /* Ns */
        { NULL, TYPE_Nx, NODE_NOSRC },  /* Nx */
        { NULL, TYPE_Ox, NODE_NOSRC },  /* Ox */
        { NULL, 0, 0 },  /* Pc */
        { NULL, 0, 0 },  /* Pf */
        { NULL, 0, 0 },  /* Po */
        { NULL, 0, 0 },  /* Pq */
        { NULL, 0, 0 },  /* Qc */
        { NULL, 0, 0 },  /* Ql */
        { NULL, 0, 0 },  /* Qo */
        { NULL, 0, 0 },  /* Qq */
        { NULL, 0, 0 },  /* Re */
        { NULL, 0, 0 },  /* Rs */
        { NULL, 0, 0 },  /* Sc */
        { NULL, 0, 0 },  /* So */
        { NULL, 0, 0 },  /* Sq */
        { NULL, 0, 0 },  /* Sm */
        { NULL, 0, 0 },  /* Sx */
        { NULL, TYPE_Sy, 0 },  /* Sy */
        { NULL, TYPE_Tn, 0 },  /* Tn */
        { NULL, 0, NODE_NOSRC },  /* Ux */
        { NULL, 0, 0 },  /* Xc */
        { NULL, 0, 0 },  /* Xo */
        { parse_mdoc_Fo, 0, 0 },  /* Fo */
        { NULL, 0, 0 },  /* Fc */
        { NULL, 0, 0 },  /* Oo */
        { NULL, 0, 0 },  /* Oc */
        { NULL, 0, 0 },  /* Bk */
        { NULL, 0, 0 },  /* Ek */
        { NULL, 0, 0 },  /* Bt */
        { NULL, 0, 0 },  /* Hf */
        { NULL, 0, 0 },  /* Fr */
        { NULL, 0, 0 },  /* Ud */
        { parse_mdoc_Lb, 0, 0 },  /* Lb */
        { NULL, 0, 0 },  /* Lp */
        { NULL, TYPE_Lk, 0 },  /* Lk */
        { NULL, TYPE_Mt, NODE_NOSRC },  /* Mt */
        { NULL, 0, 0 },  /* Brq */
        { NULL, 0, 0 },  /* Bro */
        { NULL, 0, 0 },  /* Brc */
        { NULL, 0, 0 },  /* %C */
        { NULL, 0, 0 },  /* Es */
        { NULL, 0, 0 },  /* En */
        { NULL, TYPE_Dx, NODE_NOSRC },  /* Dx */
        { NULL, 0, 0 },  /* %Q */
        { NULL, 0, 0 },  /* %U */
        { NULL, 0, 0 },  /* Ta */
};


int
mandocdb(int argc, char *argv[])
{
        struct manconf    conf;
        struct mparse    *mp;
        struct dba       *dba;
        const char       *path_arg, *progname;
        size_t            j, sz;
        int               ch, i;

        if (pledge("stdio rpath wpath cpath", NULL) == -1) {
                warn("pledge");
                return (int)MANDOCLEVEL_SYSERR;
        }

        memset(&conf, 0, sizeof(conf));

        /*
         * We accept a few different invocations.
         * The CHECKOP macro makes sure that invocation styles don't
         * clobber each other.
         */
#define CHECKOP(_op, _ch) do \
        if ((_op) != OP_DEFAULT) { \
                warnx("-%c: Conflicting option", (_ch)); \
                goto usage; \
        } while (/*CONSTCOND*/0)

        mparse_options = MPARSE_UTF8 | MPARSE_LATIN1 | MPARSE_VALIDATE;
        path_arg = NULL;
        op = OP_DEFAULT;

        while ((ch = getopt(argc, argv, "aC:Dd:npQT:tu:v")) != -1)
                switch (ch) {
                case 'a':
                        use_all = 1;
                        break;
                case 'C':
                        CHECKOP(op, ch);
                        path_arg = optarg;
                        op = OP_CONFFILE;
                        break;
                case 'D':
                        debug++;
                        break;
                case 'd':
                        CHECKOP(op, ch);
                        path_arg = optarg;
                        op = OP_UPDATE;
                        break;
                case 'n':
                        nodb = 1;
                        break;
                case 'p':
                        warnings = 1;
                        break;
                case 'Q':
                        mparse_options |= MPARSE_QUICK;
                        break;
                case 'T':
                        if (strcmp(optarg, "utf8") != 0) {
                                warnx("-T%s: Unsupported output format",
                                    optarg);
                                goto usage;
                        }
                        write_utf8 = 1;
                        break;
                case 't':
                        CHECKOP(op, ch);
                        dup2(STDOUT_FILENO, STDERR_FILENO);
                        op = OP_TEST;
                        nodb = warnings = 1;
                        break;
                case 'u':
                        CHECKOP(op, ch);
                        path_arg = optarg;
                        op = OP_DELETE;
                        break;
                case 'v':
                        /* Compatibility with espie@'s makewhatis. */
                        break;
                default:
                        goto usage;
                }

        argc -= optind;
        argv += optind;

        if (nodb) {
                if (pledge("stdio rpath", NULL) == -1) {
                        warn("pledge");
                        return (int)MANDOCLEVEL_SYSERR;
                }
        }

        if (op == OP_CONFFILE && argc > 0) {
                warnx("-C: Too many arguments");
                goto usage;
        }

        exitcode = (int)MANDOCLEVEL_OK;
        mchars_alloc();
        mp = mparse_alloc(mparse_options, MANDOC_OS_OTHER, NULL);
        mandoc_ohash_init(&mpages, 6, offsetof(struct mpage, inodev));
        mandoc_ohash_init(&mlinks, 6, offsetof(struct mlink, file));

        if (op == OP_UPDATE || op == OP_DELETE || op == OP_TEST) {

                /*
                 * Most of these deal with a specific directory.
                 * Jump into that directory first.
                 */
                if (op != OP_TEST && set_basedir(path_arg, 1) == 0)
                        goto out;

                dba = nodb ? dba_new(128) : dba_read(MANDOC_DB);
                if (dba != NULL) {
                        /*
                         * The existing database is usable.  Process
                         * all files specified on the command-line.
                         */
                        use_all = 1;
                        for (i = 0; i < argc; i++)
                                filescan(argv[i]);
                        if (nodb == 0)
                                dbprune(dba);
                } else {
                        /* Database missing or corrupt. */
                        if (op != OP_UPDATE || errno != ENOENT)
                                say(MANDOC_DB, "%s: Automatically recreating"
                                    " from scratch", strerror(errno));
                        exitcode = (int)MANDOCLEVEL_OK;
                        op = OP_DEFAULT;
                        if (treescan() == 0)
                                goto out;
                        dba = dba_new(128);
                }
                if (op != OP_DELETE)
                        mpages_merge(dba, mp);
                if (nodb == 0)
                        dbwrite(dba);
                dba_free(dba);
        } else {
                /*
                 * If we have arguments, use them as our manpaths.
                 * If we don't, use man.conf(5).
                 */
                if (argc > 0) {
                        conf.manpath.paths = mandoc_reallocarray(NULL,
                            argc, sizeof(char *));
                        conf.manpath.sz = (size_t)argc;
                        for (i = 0; i < argc; i++)
                                conf.manpath.paths[i] = mandoc_strdup(argv[i]);
                } else
                        manconf_parse(&conf, path_arg, NULL, NULL);

                if (conf.manpath.sz == 0) {
                        exitcode = (int)MANDOCLEVEL_BADARG;
                        say("", "Empty manpath");
                }

                /*
                 * First scan the tree rooted at a base directory, then
                 * build a new database and finally move it into place.
                 * Ignore zero-length directories and strip trailing
                 * slashes.
                 */
                for (j = 0; j < conf.manpath.sz; j++) {
                        sz = strlen(conf.manpath.paths[j]);
                        if (sz && conf.manpath.paths[j][sz - 1] == '/')
                                conf.manpath.paths[j][--sz] = '\0';
                        if (sz == 0)
                                continue;

                        if (j) {
                                mandoc_ohash_init(&mpages, 6,
                                    offsetof(struct mpage, inodev));
                                mandoc_ohash_init(&mlinks, 6,
                                    offsetof(struct mlink, file));
                        }

                        if (set_basedir(conf.manpath.paths[j], argc > 0) == 0)
                                continue;
                        if (treescan() == 0)
                                continue;
                        dba = dba_new(128);
                        mpages_merge(dba, mp);
                        if (nodb == 0)
                                dbwrite(dba);
                        dba_free(dba);

                        if (j + 1 < conf.manpath.sz) {
                                mpages_free();
                                ohash_delete(&mpages);
                                ohash_delete(&mlinks);
                        }
                }
        }
out:
        manconf_free(&conf);
        mparse_free(mp);
        mchars_free();
        mpages_free();
        ohash_delete(&mpages);
        ohash_delete(&mlinks);
        return exitcode;
usage:
        progname = getprogname();
        fprintf(stderr, "usage: %s [-aDnpQ] [-C file] [-Tutf8]\n"
                        "       %s [-aDnpQ] [-Tutf8] dir ...\n"
                        "       %s [-DnpQ] [-Tutf8] -d dir [file ...]\n"
                        "       %s [-Dnp] -u dir [file ...]\n"
                        "       %s [-Q] -t file ...\n",
                        progname, progname, progname, progname, progname);

        return (int)MANDOCLEVEL_BADARG;
}

/*
 * To get a singly linked list in alpha order while inserting entries
 * at the beginning, process directory entries in reverse alpha order.
 */
static int
fts_compare(const FTSENT **a, const FTSENT **b)
{
        return -strcmp((*a)->fts_name, (*b)->fts_name);
}

/*
 * Scan a directory tree rooted at "basedir" for manpages.
 * We use fts(), scanning directory parts along the way for clues to our
 * section and architecture.
 *
 * If use_all has been specified, grok all files.
 * If not, sanitise paths to the following:
 *
 *   [./]man*[/<arch>]/<name>.<section>
 *   or
 *   [./]cat<section>[/<arch>]/<name>.0
 *
 * TODO: accommodate for multi-language directories.
 */
static int
treescan(void)
{
        char             buf[PATH_MAX];
        FTS             *f;
        FTSENT          *ff;
        struct mlink    *mlink;
        int              gzip;
        enum form        dform;
        char            *dsec, *arch, *fsec, *cp;
        const char      *path;
        const char      *argv[2];

        argv[0] = ".";
        argv[1] = NULL;

        f = fts_open((char * const *)argv, FTS_PHYSICAL | FTS_NOCHDIR,
            fts_compare);
        if (f == NULL) {
                exitcode = (int)MANDOCLEVEL_SYSERR;
                say("", "&fts_open");
                return 0;
        }

        dsec = arch = NULL;
        dform = FORM_NONE;

        while ((ff = fts_read(f)) != NULL) {
                path = ff->fts_path + 2;
                switch (ff->fts_info) {

                /*
                 * Symbolic links require various sanity checks,
                 * then get handled just like regular files.
                 */
                case FTS_SL:
                        if (realpath(path, buf) == NULL) {
                                if (warnings)
                                        say(path, "&realpath");
                                continue;
                        }
                        if (strncmp(buf, basedir, basedir_len) != 0) {
                                if (warnings) say("",
                                    "%s: outside base directory", buf);
                                continue;
                        }
                        /* Use logical inode to avoid mpages dupe. */
                        if (stat(path, ff->fts_statp) == -1) {
                                if (warnings)
                                        say(path, "&stat");
                                continue;
                        }
                        if ((ff->fts_statp->st_mode & S_IFMT) != S_IFREG)
                                continue;
                        /* FALLTHROUGH */

                /*
                 * If we're a regular file, add an mlink by using the
                 * stored directory data and handling the filename.
                 */
                case FTS_F:
                        if ( ! strcmp(path, MANDOC_DB))
                                continue;
                        if ( ! use_all && ff->fts_level < 2) {
                                if (warnings)
                                        say(path, "Extraneous file");
                                continue;
                        }
                        gzip = 0;
                        fsec = NULL;
                        while (fsec == NULL) {
                                fsec = strrchr(ff->fts_name, '.');
                                if (fsec == NULL || strcmp(fsec+1, "gz"))
                                        break;
                                gzip = 1;
                                *fsec = '\0';
                                fsec = NULL;
                        }
                        if (fsec == NULL) {
                                if ( ! use_all) {
                                        if (warnings)
                                                say(path,
                                                    "No filename suffix");
                                        continue;
                                }
                        } else if ( ! strcmp(++fsec, "html")) {
                                if (warnings)
                                        say(path, "Skip html");
                                continue;
                        } else if ( ! strcmp(fsec, "ps")) {
                                if (warnings)
                                        say(path, "Skip ps");
                                continue;
                        } else if ( ! strcmp(fsec, "pdf")) {
                                if (warnings)
                                        say(path, "Skip pdf");
                                continue;
                        } else if ( ! use_all &&
                            ((dform == FORM_SRC &&
                              strncmp(fsec, dsec, strlen(dsec))) ||
                             (dform == FORM_CAT && strcmp(fsec, "0")))) {
                                if (warnings)
                                        say(path, "Wrong filename suffix");
                                continue;
                        } else
                                fsec[-1] = '\0';

                        mlink = mandoc_calloc(1, sizeof(struct mlink));
                        if (strlcpy(mlink->file, path,
                            sizeof(mlink->file)) >=
                            sizeof(mlink->file)) {
                                say(path, "Filename too long");
                                free(mlink);
                                continue;
                        }
                        mlink->dform = dform;
                        mlink->dsec = dsec;
                        mlink->arch = arch;
                        mlink->name = ff->fts_name;
                        mlink->fsec = fsec;
                        mlink->gzip = gzip;
                        mlink_add(mlink, ff->fts_statp);
                        continue;

                case FTS_D:
                case FTS_DP:
                        break;

                default:
                        if (warnings)
                                say(path, "Not a regular file");
                        continue;
                }

                switch (ff->fts_level) {
                case 0:
                        /* Ignore the root directory. */
                        break;
                case 1:
                        /*
                         * This might contain manX/ or catX/.
                         * Try to infer this from the name.
                         * If we're not in use_all, enforce it.
                         */
                        cp = ff->fts_name;
                        if (ff->fts_info == FTS_DP) {
                                dform = FORM_NONE;
                                dsec = NULL;
                                break;
                        }

                        if ( ! strncmp(cp, "man", 3)) {
                                dform = FORM_SRC;
                                dsec = cp + 3;
                        } else if ( ! strncmp(cp, "cat", 3)) {
                                dform = FORM_CAT;
                                dsec = cp + 3;
                        } else {
                                dform = FORM_NONE;
                                dsec = NULL;
                        }

                        if (dsec != NULL || use_all)
                                break;

                        if (warnings)
                                say(path, "Unknown directory part");
                        fts_set(f, ff, FTS_SKIP);
                        break;
                case 2:
                        /*
                         * Possibly our architecture.
                         * If we're descending, keep tabs on it.
                         */
                        if (ff->fts_info != FTS_DP && dsec != NULL)
                                arch = ff->fts_name;
                        else
                                arch = NULL;
                        break;
                default:
                        if (ff->fts_info == FTS_DP || use_all)
                                break;
                        if (warnings)
                                say(path, "Extraneous directory part");
                        fts_set(f, ff, FTS_SKIP);
                        break;
                }
        }

        fts_close(f);
        return 1;
}

/*
 * Add a file to the mlinks table.
 * Do not verify that it's a "valid" looking manpage (we'll do that
 * later).
 *
 * Try to infer the manual section, architecture, and page name from the
 * path, assuming it looks like
 *
 *   [./]man*[/<arch>]/<name>.<section>
 *   or
 *   [./]cat<section>[/<arch>]/<name>.0
 *
 * See treescan() for the fts(3) version of this.
 */
static void
filescan(const char *infile)
{
        struct stat      st;
        struct mlink    *mlink;
        char            *linkfile, *p, *realdir, *start, *usefile;
        size_t           realdir_len;

        assert(use_all);

        if (strncmp(infile, "./", 2) == 0)
                infile += 2;

        /*
         * We have to do lstat(2) before realpath(3) loses
         * the information whether this is a symbolic link.
         * We need to know that because for symbolic links,
         * we want to use the original file name, while for
         * regular files, we want to use the real path.
         */
        if (lstat(infile, &st) == -1) {
                exitcode = (int)MANDOCLEVEL_BADARG;
                say(infile, "&lstat");
                return;
        } else if (S_ISREG(st.st_mode) == 0 && S_ISLNK(st.st_mode) == 0) {
                exitcode = (int)MANDOCLEVEL_BADARG;
                say(infile, "Not a regular file");
                return;
        }

        /*
         * We have to resolve the file name to the real path
         * in any case for the base directory check.
         */
        if ((usefile = realpath(infile, NULL)) == NULL) {
                exitcode = (int)MANDOCLEVEL_BADARG;
                say(infile, "&realpath");
                return;
        }

        if (op == OP_TEST)
                start = usefile;
        else if (strncmp(usefile, basedir, basedir_len) == 0)
                start = usefile + basedir_len;
        else {
                exitcode = (int)MANDOCLEVEL_BADARG;
                say("", "%s: outside base directory", infile);
                free(usefile);
                return;
        }

        /*
         * Now we are sure the file is inside our tree.
         * If it is a symbolic link, ignore the real path
         * and use the original name.
         */
        do {
                if (S_ISLNK(st.st_mode) == 0)
                        break;

                /*
                 * Some implementations of realpath(3) may succeed
                 * even if the target of the link does not exist,
                 * so check again for extra safety.
                 */
                if (stat(usefile, &st) == -1) {
                        exitcode = (int)MANDOCLEVEL_BADARG;
                        say(infile, "&stat");
                        free(usefile);
                        return;
                }
                linkfile = mandoc_strdup(infile);
                if (op == OP_TEST) {
                        free(usefile);
                        start = usefile = linkfile;
                        break;
                }
                if (strncmp(infile, basedir, basedir_len) == 0) {
                        free(usefile);
                        usefile = linkfile;
                        start = usefile + basedir_len;
                        break;
                }

                /*
                 * This symbolic link points into the basedir
                 * from the outside.  Let's see whether any of
                 * the parent directories resolve to the basedir.
                 */
                p = strchr(linkfile, '\0');
                do {
                        while (*--p != '/')
                                continue;
                        *p = '\0';
                        if ((realdir = realpath(linkfile, NULL)) == NULL) {
                                exitcode = (int)MANDOCLEVEL_BADARG;
                                say(infile, "&realpath");
                                free(linkfile);
                                free(usefile);
                                return;
                        }
                        realdir_len = strlen(realdir) + 1;
                        free(realdir);
                        *p = '/';
                } while (realdir_len > basedir_len);

                /*
                 * If one of the directories resolves to the basedir,
                 * use the rest of the original name.
                 * Otherwise, the best we can do
                 * is to use the filename pointed to.
                 */
                if (realdir_len == basedir_len) {
                        free(usefile);
                        usefile = linkfile;
                        start = p + 1;
                } else {
                        free(linkfile);
                        start = usefile + basedir_len;
                }
        } while (/* CONSTCOND */ 0);

        mlink = mandoc_calloc(1, sizeof(struct mlink));
        mlink->dform = FORM_NONE;
        if (strlcpy(mlink->file, start, sizeof(mlink->file)) >=
            sizeof(mlink->file)) {
                say(start, "Filename too long");
                free(mlink);
                free(usefile);
                return;
        }

        /*
         * In test mode or when the original name is absolute
         * but outside our tree, guess the base directory.
         */

        if (op == OP_TEST || (start == usefile && *start == '/')) {
                if (strncmp(usefile, "man/", 4) == 0)
                        start = usefile + 4;
                else if ((start = strstr(usefile, "/man/")) != NULL)
                        start += 5;
                else
                        start = usefile;
        }

        /*
         * First try to guess our directory structure.
         * If we find a separator, try to look for man* or cat*.
         * If we find one of these and what's underneath is a directory,
         * assume it's an architecture.
         */
        if ((p = strchr(start, '/')) != NULL) {
                *p++ = '\0';
                if (strncmp(start, "man", 3) == 0) {
                        mlink->dform = FORM_SRC;
                        mlink->dsec = start + 3;
                } else if (strncmp(start, "cat", 3) == 0) {
                        mlink->dform = FORM_CAT;
                        mlink->dsec = start + 3;
                }

                start = p;
                if (mlink->dsec != NULL && (p = strchr(start, '/')) != NULL) {
                        *p++ = '\0';
                        mlink->arch = start;
                        start = p;
                }
        }

        /*
         * Now check the file suffix.
         * Suffix of `.0' indicates a catpage, `.1-9' is a manpage.
         */
        p = strrchr(start, '\0');
        while (p-- > start && *p != '/' && *p != '.')
                continue;

        if (*p == '.') {
                *p++ = '\0';
                mlink->fsec = p;
        }

        /*
         * Now try to parse the name.
         * Use the filename portion of the path.
         */
        mlink->name = start;
        if ((p = strrchr(start, '/')) != NULL) {
                mlink->name = p + 1;
                *p = '\0';
        }
        mlink_add(mlink, &st);
        free(usefile);
}

static void
mlink_add(struct mlink *mlink, const struct stat *st)
{
        struct inodev    inodev;
        struct mpage    *mpage;
        unsigned int     slot;

        assert(NULL != mlink->file);

        mlink->dsec = mandoc_strdup(mlink->dsec ? mlink->dsec : "");
        mlink->arch = mandoc_strdup(mlink->arch ? mlink->arch : "");
        mlink->name = mandoc_strdup(mlink->name ? mlink->name : "");
        mlink->fsec = mandoc_strdup(mlink->fsec ? mlink->fsec : "");

        if ('0' == *mlink->fsec) {
                free(mlink->fsec);
                mlink->fsec = mandoc_strdup(mlink->dsec);
                mlink->fform = FORM_CAT;
        } else if ('1' <= *mlink->fsec && '9' >= *mlink->fsec)
                mlink->fform = FORM_SRC;
        else
                mlink->fform = FORM_NONE;

        slot = ohash_qlookup(&mlinks, mlink->file);
        assert(NULL == ohash_find(&mlinks, slot));
        ohash_insert(&mlinks, slot, mlink);

        memset(&inodev, 0, sizeof(inodev));  /* Clear padding. */
        inodev.st_ino = st->st_ino;
        inodev.st_dev = st->st_dev;
        slot = ohash_lookup_memory(&mpages, (char *)&inodev,
            sizeof(struct inodev), inodev.st_ino);
        mpage = ohash_find(&mpages, slot);
        if (NULL == mpage) {
                mpage = mandoc_calloc(1, sizeof(struct mpage));
                mpage->inodev.st_ino = inodev.st_ino;
                mpage->inodev.st_dev = inodev.st_dev;
                mpage->form = FORM_NONE;
                mpage->next = mpage_head;
                mpage_head = mpage;
                ohash_insert(&mpages, slot, mpage);
        } else
                mlink->next = mpage->mlinks;
        mpage->mlinks = mlink;
        mlink->mpage = mpage;
}

static void
mlink_free(struct mlink *mlink)
{

        free(mlink->dsec);
        free(mlink->arch);
        free(mlink->name);
        free(mlink->fsec);
        free(mlink);
}

static void
mpages_free(void)
{
        struct mpage    *mpage;
        struct mlink    *mlink;

        while ((mpage = mpage_head) != NULL) {
                while ((mlink = mpage->mlinks) != NULL) {
                        mpage->mlinks = mlink->next;
                        mlink_free(mlink);
                }
                mpage_head = mpage->next;
                free(mpage->sec);
                free(mpage->arch);
                free(mpage->title);
                free(mpage->desc);
                free(mpage);
        }
}

/*
 * For each mlink to the mpage, check whether the path looks like
 * it is formatted, and if it does, check whether a source manual
 * exists by the same name, ignoring the suffix.
 * If both conditions hold, drop the mlink.
 */
static void
mlinks_undupe(struct mpage *mpage)
{
        char              buf[PATH_MAX];
        struct mlink    **prev;
        struct mlink     *mlink;
        char             *bufp;

        mpage->form = FORM_CAT;
        prev = &mpage->mlinks;
        while (NULL != (mlink = *prev)) {
                if (FORM_CAT != mlink->dform) {
                        mpage->form = FORM_NONE;
                        goto nextlink;
                }
                (void)strlcpy(buf, mlink->file, sizeof(buf));
                bufp = strstr(buf, "cat");
                assert(NULL != bufp);
                memcpy(bufp, "man", 3);
                if (NULL != (bufp = strrchr(buf, '.')))
                        *++bufp = '\0';
                (void)strlcat(buf, mlink->dsec, sizeof(buf));
                if (NULL == ohash_find(&mlinks,
                    ohash_qlookup(&mlinks, buf)))
                        goto nextlink;
                if (warnings)
                        say(mlink->file, "Man source exists: %s", buf);
                if (use_all)
                        goto nextlink;
                *prev = mlink->next;
                mlink_free(mlink);
                continue;
nextlink:
                prev = &(*prev)->next;
        }
}

static void
mlink_check(struct mpage *mpage, struct mlink *mlink)
{
        struct str      *str;
        unsigned int     slot;

        /*
         * Check whether the manual section given in a file
         * agrees with the directory where the file is located.
         * Some manuals have suffixes like (3p) on their
         * section number either inside the file or in the
         * directory name, some are linked into more than one
         * section, like encrypt(1) = makekey(8).
         */

        if (FORM_SRC == mpage->form &&
            strcasecmp(mpage->sec, mlink->dsec))
                say(mlink->file, "Section \"%s\" manual in %s directory",
                    mpage->sec, mlink->dsec);

        /*
         * Manual page directories exist for each kernel
         * architecture as returned by machine(1).
         * However, many manuals only depend on the
         * application architecture as returned by arch(1).
         * For example, some (2/ARM) manuals are shared
         * across the "armish" and "zaurus" kernel
         * architectures.
         * A few manuals are even shared across completely
         * different architectures, for example fdformat(1)
         * on amd64, i386, and sparc64.
         */

        if (strcasecmp(mpage->arch, mlink->arch))
                say(mlink->file, "Architecture \"%s\" manual in "
                    "\"%s\" directory", mpage->arch, mlink->arch);

        /*
         * XXX
         * parse_cat() doesn't set NAME_TITLE yet.
         */

        if (FORM_CAT == mpage->form)
                return;

        /*
         * Check whether this mlink
         * appears as a name in the NAME section.
         */

        slot = ohash_qlookup(&names, mlink->name);
        str = ohash_find(&names, slot);
        assert(NULL != str);
        if ( ! (NAME_TITLE & str->mask))
                say(mlink->file, "Name missing in NAME section");
}

/*
 * Run through the files in the global vector "mpages"
 * and add them to the database specified in "basedir".
 *
 * This handles the parsing scheme itself, using the cues of directory
 * and filename to determine whether the file is parsable or not.
 */
static void
mpages_merge(struct dba *dba, struct mparse *mp)
{
        struct mpage            *mpage, *mpage_dest;
        struct mlink            *mlink, *mlink_dest;
        struct roff_meta        *meta;
        char                    *cp;
        int                      fd;

        for (mpage = mpage_head; mpage != NULL; mpage = mpage->next) {
                mlinks_undupe(mpage);
                if ((mlink = mpage->mlinks) == NULL)
                        continue;

                name_mask = NAME_MASK;
                mandoc_ohash_init(&names, 4, offsetof(struct str, key));
                mandoc_ohash_init(&strings, 6, offsetof(struct str, key));
                mparse_reset(mp);
                meta = NULL;

                if ((fd = mparse_open(mp, mlink->file)) == -1) {
                        say(mlink->file, "&open");
                        goto nextpage;
                }

                /*
                 * Interpret the file as mdoc(7) or man(7) source
                 * code, unless it is known to be formatted.
                 */
                if (mlink->dform != FORM_CAT || mlink->fform != FORM_CAT) {
                        mparse_readfd(mp, fd, mlink->file);
                        close(fd);
                        fd = -1;
                        meta = mparse_result(mp);
                }

                if (meta != NULL && meta->sodest != NULL) {
                        mlink_dest = ohash_find(&mlinks,
                            ohash_qlookup(&mlinks, meta->sodest));
                        if (mlink_dest == NULL) {
                                mandoc_asprintf(&cp, "%s.gz", meta->sodest);
                                mlink_dest = ohash_find(&mlinks,
                                    ohash_qlookup(&mlinks, cp));
                                free(cp);
                        }
                        if (mlink_dest != NULL) {

                                /* The .so target exists. */

                                mpage_dest = mlink_dest->mpage;
                                while (1) {
                                        mlink->mpage = mpage_dest;

                                        /*
                                         * If the target was already
                                         * processed, add the links
                                         * to the database now.
                                         * Otherwise, this will
                                         * happen when we come
                                         * to the target.
                                         */

                                        if (mpage_dest->dba != NULL)
                                                dbadd_mlink(mlink);

                                        if (mlink->next == NULL)
                                                break;
                                        mlink = mlink->next;
                                }

                                /* Move all links to the target. */

                                mlink->next = mlink_dest->next;
                                mlink_dest->next = mpage->mlinks;
                                mpage->mlinks = NULL;
                                goto nextpage;
                        }
                        meta->macroset = MACROSET_NONE;
                }
                if (meta != NULL && meta->macroset == MACROSET_MDOC) {
                        mpage->form = FORM_SRC;
                        mpage->sec = meta->msec;
                        mpage->sec = mandoc_strdup(
                            mpage->sec == NULL ? "" : mpage->sec);
                        mpage->arch = meta->arch;
                        mpage->arch = mandoc_strdup(
                            mpage->arch == NULL ? "" : mpage->arch);
                        mpage->title = mandoc_strdup(meta->title);
                } else if (meta != NULL && meta->macroset == MACROSET_MAN) {
                        if (*meta->msec != '\0' || *meta->title != '\0') {
                                mpage->form = FORM_SRC;
                                mpage->sec = mandoc_strdup(meta->msec);
                                mpage->arch = mandoc_strdup(mlink->arch);
                                mpage->title = mandoc_strdup(meta->title);
                        } else
                                meta = NULL;
                }

                assert(mpage->desc == NULL);
                if (meta == NULL || meta->sodest != NULL) {
                        mpage->sec = mandoc_strdup(mlink->dsec);
                        mpage->arch = mandoc_strdup(mlink->arch);
                        mpage->title = mandoc_strdup(mlink->name);
                        if (meta == NULL) {
                                mpage->form = FORM_CAT;
                                parse_cat(mpage, fd);
                        } else
                                mpage->form = FORM_SRC;
                } else if (meta->macroset == MACROSET_MDOC)
                        parse_mdoc(mpage, meta, meta->first);
                else
                        parse_man(mpage, meta, meta->first);
                if (mpage->desc == NULL) {
                        mpage->desc = mandoc_strdup(mlink->name);
                        if (warnings)
                                say(mlink->file, "No one-line description, "
                                    "using filename \"%s\"", mlink->name);
                }

                for (mlink = mpage->mlinks;
                     mlink != NULL;
                     mlink = mlink->next) {
                        putkey(mpage, mlink->name, NAME_FILE);
                        if (warnings && !use_all)
                                mlink_check(mpage, mlink);
                }

                dbadd(dba, mpage);

nextpage:
                ohash_delete(&strings);
                ohash_delete(&names);
        }
}

static void
parse_cat(struct mpage *mpage, int fd)
{
        FILE            *stream;
        struct mlink    *mlink;
        char            *line, *p, *title, *sec;
        size_t           linesz, plen, titlesz;
        ssize_t          len;
        int              offs;

        mlink = mpage->mlinks;
        stream = fd == -1 ? fopen(mlink->file, "r") : fdopen(fd, "r");
        if (stream == NULL) {
                if (fd != -1)
                        close(fd);
                if (warnings)
                        say(mlink->file, "&fopen");
                return;
        }

        line = NULL;
        linesz = 0;

        /* Parse the section number from the header line. */

        while (getline(&line, &linesz, stream) != -1) {
                if (*line == '\n')
                        continue;
                if ((sec = strchr(line, '(')) == NULL)
                        break;
                if ((p = strchr(++sec, ')')) == NULL)
                        break;
                free(mpage->sec);
                mpage->sec = mandoc_strndup(sec, p - sec);
                if (warnings && *mlink->dsec != '\0' &&
                    strcasecmp(mpage->sec, mlink->dsec))
                        say(mlink->file,
                            "Section \"%s\" manual in %s directory",
                            mpage->sec, mlink->dsec);
                break;
        }

        /* Skip to first blank line. */

        while (line == NULL || *line != '\n')
                if (getline(&line, &linesz, stream) == -1)
                        break;

        /*
         * Assume the first line that is not indented
         * is the first section header.  Skip to it.
         */

        while (getline(&line, &linesz, stream) != -1)
                if (*line != '\n' && *line != ' ')
                        break;

        /*
         * Read up until the next section into a buffer.
         * Strip the leading and trailing newline from each read line,
         * appending a trailing space.
         * Ignore empty (whitespace-only) lines.
         */

        titlesz = 0;
        title = NULL;

        while ((len = getline(&line, &linesz, stream)) != -1) {
                if (*line != ' ')
                        break;
                offs = 0;
                while (isspace((unsigned char)line[offs]))
                        offs++;
                if (line[offs] == '\0')
                        continue;
                title = mandoc_realloc(title, titlesz + len - offs);
                memcpy(title + titlesz, line + offs, len - offs);
                titlesz += len - offs;
                title[titlesz - 1] = ' ';
        }
        free(line);

        /*
         * If no page content can be found, or the input line
         * is already the next section header, or there is no
         * trailing newline, reuse the page title as the page
         * description.
         */

        if (NULL == title || '\0' == *title) {
                if (warnings)
                        say(mlink->file, "Cannot find NAME section");
                fclose(stream);
                free(title);
                return;
        }

        title[titlesz - 1] = '\0';

        /*
         * Skip to the first dash.
         * Use the remaining line as the description (no more than 70
         * bytes).
         */

        if (NULL != (p = strstr(title, "- "))) {
                for (p += 2; ' ' == *p || '\b' == *p; p++)
                        /* Skip to next word. */ ;
        } else {
                if (warnings)
                        say(mlink->file, "No dash in title line, "
                            "reusing \"%s\" as one-line description", title);
                p = title;
        }

        plen = strlen(p);

        /* Strip backspace-encoding from line. */

        while (NULL != (line = memchr(p, '\b', plen))) {
                len = line - p;
                if (0 == len) {
                        memmove(line, line + 1, plen--);
                        continue;
                }
                memmove(line - 1, line + 1, plen - len);
                plen -= 2;
        }

        /*
         * Cut off excessive one-line descriptions.
         * Bad pages are not worth better heuristics.
         */

        mpage->desc = mandoc_strndup(p, 150);
        fclose(stream);
        free(title);
}

/*
 * Put a type/word pair into the word database for this particular file.
 */
static void
putkey(const struct mpage *mpage, char *value, uint64_t type)
{
        putkeys(mpage, value, strlen(value), type);
}

/*
 * Grok all nodes at or below a certain mdoc node into putkey().
 */
static void
putmdockey(const struct mpage *mpage,
        const struct roff_node *n, uint64_t m, int taboo)
{

        for ( ; NULL != n; n = n->next) {
                if (n->flags & taboo)
                        continue;
                if (NULL != n->child)
                        putmdockey(mpage, n->child, m, taboo);
                if (n->type == ROFFT_TEXT)
                        putkey(mpage, n->string, m);
        }
}

static void
parse_man(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{
        const struct roff_node *head, *body;
        char            *start, *title;
        char             byte;
        size_t           sz;

        if (n == NULL)
                return;

        /*
         * We're only searching for one thing: the first text child in
         * the BODY of a NAME section.  Since we don't keep track of
         * sections in -man, run some hoops to find out whether we're in
         * the correct section or not.
         */

        if (n->type == ROFFT_BODY && n->tok == MAN_SH) {
                body = n;
                if ((head = body->parent->head) != NULL &&
                    (head = head->child) != NULL &&
                    head->next == NULL &&
                    head->type == ROFFT_TEXT &&
                    strcmp(head->string, "NAME") == 0 &&
                    body->child != NULL) {

                        /*
                         * Suck the entire NAME section into memory.
                         * Yes, we might run away.
                         * But too many manuals have big, spread-out
                         * NAME sections over many lines.
                         */

                        title = NULL;
                        deroff(&title, body);
                        if (NULL == title)
                                return;

                        /*
                         * Go through a special heuristic dance here.
                         * Conventionally, one or more manual names are
                         * comma-specified prior to a whitespace, then a
                         * dash, then a description.  Try to puzzle out
                         * the name parts here.
                         */

                        start = title;
                        for ( ;; ) {
                                sz = strcspn(start, " ,");
                                if ('\0' == start[sz])
                                        break;

                                byte = start[sz];
                                start[sz] = '\0';

                                /*
                                 * Assume a stray trailing comma in the
                                 * name list if a name begins with a dash.
                                 */

                                if ('-' == start[0] ||
                                    ('\\' == start[0] && '-' == start[1]))
                                        break;

                                putkey(mpage, start, NAME_TITLE);
                                if ( ! (mpage->name_head_done ||
                                    strcasecmp(start, meta->title))) {
                                        putkey(mpage, start, NAME_HEAD);
                                        mpage->name_head_done = 1;
                                }

                                if (' ' == byte) {
                                        start += sz + 1;
                                        break;
                                }

                                assert(',' == byte);
                                start += sz + 1;
                                while (' ' == *start)
                                        start++;
                        }

                        if (start == title) {
                                putkey(mpage, start, NAME_TITLE);
                                if ( ! (mpage->name_head_done ||
                                    strcasecmp(start, meta->title))) {
                                        putkey(mpage, start, NAME_HEAD);
                                        mpage->name_head_done = 1;
                                }
                                free(title);
                                return;
                        }

                        while (isspace((unsigned char)*start))
                                start++;

                        if (0 == strncmp(start, "-", 1))
                                start += 1;
                        else if (0 == strncmp(start, "\\-\\-", 4))
                                start += 4;
                        else if (0 == strncmp(start, "\\-", 2))
                                start += 2;
                        else if (0 == strncmp(start, "\\(en", 4))
                                start += 4;
                        else if (0 == strncmp(start, "\\(em", 4))
                                start += 4;

                        while (' ' == *start)
                                start++;

                        /*
                         * Cut off excessive one-line descriptions.
                         * Bad pages are not worth better heuristics.
                         */

                        mpage->desc = mandoc_strndup(start, 150);
                        free(title);
                        return;
                }
        }

        for (n = n->child; n; n = n->next) {
                if (NULL != mpage->desc)
                        break;
                parse_man(mpage, meta, n);
        }
}

static void
parse_mdoc(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{
        const struct mdoc_handler *handler;

        for (n = n->child; n != NULL; n = n->next) {
                if (n->tok == TOKEN_NONE || n->tok < ROFF_MAX)
                        continue;
                assert(n->tok >= MDOC_Dd && n->tok < MDOC_MAX);
                handler = mdoc_handlers + (n->tok - MDOC_Dd);
                if (n->flags & handler->taboo)
                        continue;

                switch (n->type) {
                case ROFFT_ELEM:
                case ROFFT_BLOCK:
                case ROFFT_HEAD:
                case ROFFT_BODY:
                case ROFFT_TAIL:
                        if (handler->fp != NULL &&
                            (*handler->fp)(mpage, meta, n) == 0)
                                break;
                        if (handler->mask)
                                putmdockey(mpage, n->child,
                                    handler->mask, handler->taboo);
                        break;
                default:
                        continue;
                }
                if (NULL != n->child)
                        parse_mdoc(mpage, meta, n);
        }
}

static int
parse_mdoc_Fa(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{
        uint64_t mask;

        mask = TYPE_Fa;
        if (n->sec == SEC_SYNOPSIS)
                mask |= TYPE_Vt;

        putmdockey(mpage, n->child, mask, 0);
        return 0;
}

static int
parse_mdoc_Fd(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{
        char            *start, *end;
        size_t           sz;

        if (SEC_SYNOPSIS != n->sec ||
            NULL == (n = n->child) ||
            n->type != ROFFT_TEXT)
                return 0;

        /*
         * Only consider those `Fd' macro fields that begin with an
         * "inclusion" token (versus, e.g., #define).
         */

        if (strcmp("#include", n->string))
                return 0;

        if ((n = n->next) == NULL || n->type != ROFFT_TEXT)
                return 0;

        /*
         * Strip away the enclosing angle brackets and make sure we're
         * not zero-length.
         */

        start = n->string;
        if ('<' == *start || '"' == *start)
                start++;

        if (0 == (sz = strlen(start)))
                return 0;

        end = &start[(int)sz - 1];
        if ('>' == *end || '"' == *end)
                end--;

        if (end > start)
                putkeys(mpage, start, end - start + 1, TYPE_In);
        return 0;
}

static void
parse_mdoc_fname(struct mpage *mpage, const struct roff_node *n)
{
        char    *cp;
        size_t   sz;

        if (n->type != ROFFT_TEXT)
                return;

        /* Skip function pointer punctuation. */

        cp = n->string;
        while (*cp == '(' || *cp == '*')
                cp++;
        sz = strcspn(cp, "()");

        putkeys(mpage, cp, sz, TYPE_Fn);
        if (n->sec == SEC_SYNOPSIS)
                putkeys(mpage, cp, sz, NAME_SYN);
}

static int
parse_mdoc_Fn(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{
        uint64_t mask;

        if (n->child == NULL)
                return 0;

        parse_mdoc_fname(mpage, n->child);

        n = n->child->next;
        if (n != NULL && n->type == ROFFT_TEXT) {
                mask = TYPE_Fa;
                if (n->sec == SEC_SYNOPSIS)
                        mask |= TYPE_Vt;
                putmdockey(mpage, n, mask, 0);
        }

        return 0;
}

static int
parse_mdoc_Fo(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{

        if (n->type != ROFFT_HEAD)
                return 1;

        if (n->child != NULL)
                parse_mdoc_fname(mpage, n->child);

        return 0;
}

static int
parse_mdoc_Lb(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{
        char *cp;

        for (n = n->child; n != NULL; n = n->next) {
                if (n->flags & NODE_NOSRC)
                        continue;
                cp = n->string;
                if (n->sec == SEC_SYNOPSIS)
                        mandoc_asprintf(&cp, "lib%s", cp);
                putkey(mpage, cp, TYPE_Lb);
                if (n->sec == SEC_SYNOPSIS)
                        free(cp);
        }
        return 0;
}

static int
parse_mdoc_Va(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{
        char *cp;

        if (n->type != ROFFT_ELEM && n->type != ROFFT_BODY)
                return 0;

        if (n->child != NULL &&
            n->child->next == NULL &&
            n->child->type == ROFFT_TEXT)
                return 1;

        cp = NULL;
        deroff(&cp, n);
        if (cp != NULL) {
                putkey(mpage, cp, TYPE_Vt | (n->tok == MDOC_Va ||
                    n->type == ROFFT_BODY ? TYPE_Va : 0));
                free(cp);
        }

        return 0;
}

static int
parse_mdoc_Xr(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{
        char    *cp;

        if (NULL == (n = n->child))
                return 0;

        if (NULL == n->next) {
                putkey(mpage, n->string, TYPE_Xr);
                return 0;
        }

        mandoc_asprintf(&cp, "%s(%s)", n->string, n->next->string);
        putkey(mpage, cp, TYPE_Xr);
        free(cp);
        return 0;
}

static int
parse_mdoc_Nd(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{

        if (n->type == ROFFT_BODY)
                deroff(&mpage->desc, n);
        return 0;
}

static int
parse_mdoc_Nm(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{

        if (SEC_NAME == n->sec)
                putmdockey(mpage, n->child, NAME_TITLE, 0);
        else if (n->sec == SEC_SYNOPSIS && n->type == ROFFT_HEAD) {
                if (n->child == NULL)
                        putkey(mpage, meta->name, NAME_SYN);
                else
                        putmdockey(mpage, n->child, NAME_SYN, 0);
        }
        if ( ! (mpage->name_head_done ||
            n->child == NULL || n->child->string == NULL ||
            strcasecmp(n->child->string, meta->title))) {
                putkey(mpage, n->child->string, NAME_HEAD);
                mpage->name_head_done = 1;
        }
        return 0;
}

static int
parse_mdoc_Sh(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{

        return n->sec == SEC_CUSTOM && n->type == ROFFT_HEAD;
}

static int
parse_mdoc_head(struct mpage *mpage, const struct roff_meta *meta,
        const struct roff_node *n)
{

        return n->type == ROFFT_HEAD;
}

/*
 * Add a string to the hash table for the current manual.
 * Each string has a bitmask telling which macros it belongs to.
 * When we finish the manual, we'll dump the table.
 */
static void
putkeys(const struct mpage *mpage, char *cp, size_t sz, uint64_t v)
{
        struct ohash    *htab;
        struct str      *s;
        const char      *end;
        unsigned int     slot;
        int              i, mustfree;

        if (0 == sz)
                return;

        mustfree = render_string(&cp, &sz);

        if (TYPE_Nm & v) {
                htab = &names;
                v &= name_mask;
                if (v & NAME_FIRST)
                        name_mask &= ~NAME_FIRST;
                if (debug > 1)
                        say(mpage->mlinks->file,
                            "Adding name %*s, bits=0x%llx", (int)sz, cp,
                            (unsigned long long)v);
        } else {
                htab = &strings;
                if (debug > 1)
                    for (i = 0; i < KEY_MAX; i++)
                        if ((uint64_t)1 << i & v)
                            say(mpage->mlinks->file,
                                "Adding key %s=%*s",
                                mansearch_keynames[i], (int)sz, cp);
        }

        end = cp + sz;
        slot = ohash_qlookupi(htab, cp, &end);
        s = ohash_find(htab, slot);

        if (NULL != s && mpage == s->mpage) {
                s->mask |= v;
                return;
        } else if (NULL == s) {
                s = mandoc_calloc(1, sizeof(struct str) + sz + 1);
                memcpy(s->key, cp, sz);
                ohash_insert(htab, slot, s);
        }
        s->mpage = mpage;
        s->mask = v;

        if (mustfree)
                free(cp);
}

/*
 * Take a Unicode codepoint and produce its UTF-8 encoding.
 * This isn't the best way to do this, but it works.
 * The magic numbers are from the UTF-8 packaging.
 * Read the UTF-8 spec or the utf8(7) manual page for details.
 */
static size_t
utf8(unsigned int cp, char out[5])
{
        size_t           rc;

        if (cp <= 0x7f) {
                rc = 1;
                out[0] = (char)cp;
        } else if (cp <= 0x7ff) {
                rc = 2;
                out[0] = (cp >> 6  & 31) | 192;
                out[1] = (cp       & 63) | 128;
        } else if (cp >= 0xd800 && cp <= 0xdfff) {
                rc = 0; /* reject UTF-16 surrogate */
        } else if (cp <= 0xffff) {
                rc = 3;
                out[0] = (cp >> 12 & 15) | 224;
                out[1] = (cp >> 6  & 63) | 128;
                out[2] = (cp       & 63) | 128;
        } else if (cp <= 0x10ffff) {
                rc = 4;
                out[0] = (cp >> 18 &  7) | 240;
                out[1] = (cp >> 12 & 63) | 128;
                out[2] = (cp >> 6  & 63) | 128;
                out[3] = (cp       & 63) | 128;
        } else
                rc = 0;

        out[rc] = '\0';
        return rc;
}

/*
 * If the string contains escape sequences,
 * replace it with an allocated rendering and return 1,
 * such that the caller can free it after use.
 * Otherwise, do nothing and return 0.
 */
static int
render_string(char **public, size_t *psz)
{
        const char      *src, *scp, *addcp, *seq;
        char            *dst;
        size_t           ssz, dsz, addsz;
        char             utfbuf[7], res[6];
        int              seqlen, unicode;

        res[0] = '\\';
        res[1] = '\t';
        res[2] = ASCII_NBRSP;
        res[3] = ASCII_HYPH;
        res[4] = ASCII_BREAK;
        res[5] = '\0';

        src = scp = *public;
        ssz = *psz;
        dst = NULL;
        dsz = 0;

        while (scp < src + *psz) {

                /* Leave normal characters unchanged. */

                if (strchr(res, *scp) == NULL) {
                        if (dst != NULL)
                                dst[dsz++] = *scp;
                        scp++;
                        continue;
                }

                /*
                 * Found something that requires replacing,
                 * make sure we have a destination buffer.
                 */

                if (dst == NULL) {
                        dst = mandoc_malloc(ssz + 1);
                        dsz = scp - src;
                        memcpy(dst, src, dsz);
                }

                /* Handle single-char special characters. */

                switch (*scp) {
                case '\\':
                        break;
                case '\t':
                case ASCII_NBRSP:
                        dst[dsz++] = ' ';
                        scp++;
                        continue;
                case ASCII_HYPH:
                        dst[dsz++] = '-';
                        /* FALLTHROUGH */
                case ASCII_BREAK:
                        scp++;
                        continue;
                default:
                        abort();
                }

                /*
                 * Found an escape sequence.
                 * Read past the slash, then parse it.
                 * Ignore everything except characters.
                 */

                scp++;
                switch (mandoc_escape(&scp, &seq, &seqlen)) {
                case ESCAPE_UNICODE:
                        unicode = mchars_num2uc(seq + 1, seqlen - 1);
                        break;
                case ESCAPE_NUMBERED:
                        unicode = mchars_num2char(seq, seqlen);
                        break;
                case ESCAPE_SPECIAL:
                        unicode = mchars_spec2cp(seq, seqlen);
                        break;
                default:
                        unicode = -1;
                        break;
                }
                if (unicode <= 0)
                        continue;

                /*
                 * Render the special character
                 * as either UTF-8 or ASCII.
                 */

                if (write_utf8) {
                        addsz = utf8(unicode, utfbuf);
                        if (addsz == 0)
                                continue;
                        addcp = utfbuf;
                } else {
                        addcp = mchars_uc2str(unicode);
                        if (addcp == NULL)
                                continue;
                        if (*addcp == ASCII_NBRSP)
                                addcp = " ";
                        addsz = strlen(addcp);
                }

                /* Copy the rendered glyph into the stream. */

                ssz += addsz;
                dst = mandoc_realloc(dst, ssz + 1);
                memcpy(dst + dsz, addcp, addsz);
                dsz += addsz;
        }
        if (dst != NULL) {
                *public = dst;
                *psz = dsz;
        }

        /* Trim trailing whitespace and NUL-terminate. */

        while (*psz > 0 && (*public)[*psz - 1] == ' ')
                --*psz;
        if (dst != NULL) {
                (*public)[*psz] = '\0';
                return 1;
        } else
                return 0;
}

static void
dbadd_mlink(const struct mlink *mlink)
{
        dba_page_alias(mlink->mpage->dba, mlink->name, NAME_FILE);
        dba_page_add(mlink->mpage->dba, DBP_SECT, mlink->dsec);
        dba_page_add(mlink->mpage->dba, DBP_SECT, mlink->fsec);
        dba_page_add(mlink->mpage->dba, DBP_ARCH, mlink->arch);
        dba_page_add(mlink->mpage->dba, DBP_FILE, mlink->file);
}

/*
 * Flush the current page's terms (and their bits) into the database.
 * Also, handle escape sequences at the last possible moment.
 */
static void
dbadd(struct dba *dba, struct mpage *mpage)
{
        struct mlink    *mlink;
        struct str      *key;
        char            *cp;
        uint64_t         mask;
        size_t           i;
        unsigned int     slot;
        int              mustfree;

        mlink = mpage->mlinks;

        if (nodb) {
                for (key = ohash_first(&names, &slot); NULL != key;
                     key = ohash_next(&names, &slot))
                        free(key);
                for (key = ohash_first(&strings, &slot); NULL != key;
                     key = ohash_next(&strings, &slot))
                        free(key);
                if (0 == debug)
                        return;
                while (NULL != mlink) {
                        fputs(mlink->name, stdout);
                        if (NULL == mlink->next ||
                            strcmp(mlink->dsec, mlink->next->dsec) ||
                            strcmp(mlink->fsec, mlink->next->fsec) ||
                            strcmp(mlink->arch, mlink->next->arch)) {
                                putchar('(');
                                if ('\0' == *mlink->dsec)
                                        fputs(mlink->fsec, stdout);
                                else
                                        fputs(mlink->dsec, stdout);
                                if ('\0' != *mlink->arch)
                                        printf("/%s", mlink->arch);
                                putchar(')');
                        }
                        mlink = mlink->next;
                        if (NULL != mlink)
                                fputs(", ", stdout);
                }
                printf(" - %s\n", mpage->desc);
                return;
        }

        if (debug)
                say(mlink->file, "Adding to database");

        cp = mpage->desc;
        i = strlen(cp);
        mustfree = render_string(&cp, &i);
        mpage->dba = dba_page_new(dba->pages,
            *mpage->arch == '\0' ? mlink->arch : mpage->arch,
            cp, mlink->file, mpage->form);
        if (mustfree)
                free(cp);
        dba_page_add(mpage->dba, DBP_SECT, mpage->sec);

        while (mlink != NULL) {
                dbadd_mlink(mlink);
                mlink = mlink->next;
        }

        for (key = ohash_first(&names, &slot); NULL != key;
             key = ohash_next(&names, &slot)) {
                assert(key->mpage == mpage);
                dba_page_alias(mpage->dba, key->key, key->mask);
                free(key);
        }
        for (key = ohash_first(&strings, &slot); NULL != key;
             key = ohash_next(&strings, &slot)) {
                assert(key->mpage == mpage);
                i = 0;
                for (mask = TYPE_Xr; mask <= TYPE_Lb; mask *= 2) {
                        if (key->mask & mask)
                                dba_macro_add(dba->macros, i,
                                    key->key, mpage->dba);
                        i++;
                }
                free(key);
        }
}

static void
dbprune(struct dba *dba)
{
        struct dba_array        *page, *files;
        char                    *file;

        dba_array_FOREACH(dba->pages, page) {
                files = dba_array_get(page, DBP_FILE);
                dba_array_FOREACH(files, file) {
                        if (*file < ' ')
                                file++;
                        if (ohash_find(&mlinks, ohash_qlookup(&mlinks,
                            file)) != NULL) {
                                if (debug)
                                        say(file, "Deleting from database");
                                dba_array_del(dba->pages);
                                break;
                        }
                }
        }
}

/*
 * Write the database from memory to disk.
 */
static void
dbwrite(struct dba *dba)
{
        struct stat      sb1, sb2;
        char             tfn[33], *cp1, *cp2;
        off_t            i;
        int              fd1, fd2;

        /*
         * Do not write empty databases, and delete existing ones
         * when makewhatis -u causes them to become empty.
         */

        dba_array_start(dba->pages);
        if (dba_array_next(dba->pages) == NULL) {
                if (unlink(MANDOC_DB) == -1 && errno != ENOENT)
                        say(MANDOC_DB, "&unlink");
                return;
        }

        /*
         * Build the database in a temporary file,
         * then atomically move it into place.
         */

        if (dba_write(MANDOC_DB "~", dba) != -1) {
                if (rename(MANDOC_DB "~", MANDOC_DB) == -1) {
                        exitcode = (int)MANDOCLEVEL_SYSERR;
                        say(MANDOC_DB, "&rename");
                        unlink(MANDOC_DB "~");
                }
                return;
        }

        /*
         * We lack write permission and cannot replace the database
         * file, but let's at least check whether the data changed.
         */

        (void)strlcpy(tfn, "/tmp/mandocdb.XXXXXXXX", sizeof(tfn));
        if (mkdtemp(tfn) == NULL) {
                exitcode = (int)MANDOCLEVEL_SYSERR;
                say("", "&%s", tfn);
                return;
        }
        cp1 = cp2 = MAP_FAILED;
        fd1 = fd2 = -1;
        (void)strlcat(tfn, "/" MANDOC_DB, sizeof(tfn));
        if (dba_write(tfn, dba) == -1) {
                say(tfn, "&dba_write");
                goto err;
        }
        if ((fd1 = open(MANDOC_DB, O_RDONLY)) == -1) {
                say(MANDOC_DB, "&open");
                goto err;
        }
        if ((fd2 = open(tfn, O_RDONLY)) == -1) {
                say(tfn, "&open");
                goto err;
        }
        if (fstat(fd1, &sb1) == -1) {
                say(MANDOC_DB, "&fstat");
                goto err;
        }
        if (fstat(fd2, &sb2) == -1) {
                say(tfn, "&fstat");
                goto err;
        }
        if (sb1.st_size != sb2.st_size)
                goto err;
        if ((cp1 = mmap(NULL, sb1.st_size, PROT_READ, MAP_PRIVATE,
            fd1, 0)) == MAP_FAILED) {
                say(MANDOC_DB, "&mmap");
                goto err;
        }
        if ((cp2 = mmap(NULL, sb2.st_size, PROT_READ, MAP_PRIVATE,
            fd2, 0)) == MAP_FAILED) {
                say(tfn, "&mmap");
                goto err;
        }
        for (i = 0; i < sb1.st_size; i++)
                if (cp1[i] != cp2[i])
                        goto err;
        goto out;

err:
        exitcode = (int)MANDOCLEVEL_SYSERR;
        say(MANDOC_DB, "Data changed, but cannot replace database");

out:
        if (cp1 != MAP_FAILED)
                munmap(cp1, sb1.st_size);
        if (cp2 != MAP_FAILED)
                munmap(cp2, sb2.st_size);
        if (fd1 != -1)
                close(fd1);
        if (fd2 != -1)
                close(fd2);
        unlink(tfn);
        *strrchr(tfn, '/') = '\0';
        rmdir(tfn);
}

static int
set_basedir(const char *targetdir, int report_baddir)
{
        static char      startdir[PATH_MAX];
        static int       getcwd_status;  /* 1 = ok, 2 = failure */
        static int       chdir_status;  /* 1 = changed directory */

        /*
         * Remember the original working directory, if possible.
         * This will be needed if the second or a later directory
         * on the command line is given as a relative path.
         * Do not error out if the current directory is not
         * searchable: Maybe it won't be needed after all.
         */
        if (getcwd_status == 0) {
                if (getcwd(startdir, sizeof(startdir)) == NULL) {
                        getcwd_status = 2;
                        (void)strlcpy(startdir, strerror(errno),
                            sizeof(startdir));
                } else
                        getcwd_status = 1;
        }

        /*
         * We are leaving the old base directory.
         * Do not use it any longer, not even for messages.
         */
        *basedir = '\0';
        basedir_len = 0;

        /*
         * If and only if the directory was changed earlier and
         * the next directory to process is given as a relative path,
         * first go back, or bail out if that is impossible.
         */
        if (chdir_status && *targetdir != '/') {
                if (getcwd_status == 2) {
                        exitcode = (int)MANDOCLEVEL_SYSERR;
                        say("", "getcwd: %s", startdir);
                        return 0;
                }
                if (chdir(startdir) == -1) {
                        exitcode = (int)MANDOCLEVEL_SYSERR;
                        say("", "&chdir %s", startdir);
                        return 0;
                }
        }

        /*
         * Always resolve basedir to the canonicalized absolute
         * pathname and append a trailing slash, such that
         * we can reliably check whether files are inside.
         */
        if (realpath(targetdir, basedir) == NULL) {
                if (report_baddir || errno != ENOENT) {
                        exitcode = (int)MANDOCLEVEL_BADARG;
                        say("", "&%s: realpath", targetdir);
                }
                *basedir = '\0';
                return 0;
        } else if (chdir(basedir) == -1) {
                if (report_baddir || errno != ENOENT) {
                        exitcode = (int)MANDOCLEVEL_BADARG;
                        say("", "&chdir");
                }
                *basedir = '\0';
                return 0;
        }
        chdir_status = 1;
        basedir_len = strlen(basedir);
        if (basedir[basedir_len - 1] != '/') {
                if (basedir_len >= PATH_MAX - 1) {
                        exitcode = (int)MANDOCLEVEL_SYSERR;
                        say("", "Filename too long");
                        *basedir = '\0';
                        basedir_len = 0;
                        return 0;
                }
                basedir[basedir_len++] = '/';
                basedir[basedir_len] = '\0';
        }
        return 1;
}

static void
say(const char *file, const char *format, ...)
{
        va_list          ap;
        int              use_errno;

        if (*basedir != '\0')
                fprintf(stderr, "%s", basedir);
        if (*basedir != '\0' && *file != '\0')
                fputc('/', stderr);
        if (*file != '\0')
                fprintf(stderr, "%s", file);

        use_errno = 1;
        if (format != NULL) {
                switch (*format) {
                case '&':
                        format++;
                        break;
                case '\0':
                        format = NULL;
                        break;
                default:
                        use_errno = 0;
                        break;
                }
        }
        if (format != NULL) {
                if (*basedir != '\0' || *file != '\0')
                        fputs(": ", stderr);
                va_start(ap, format);
                vfprintf(stderr, format, ap);
                va_end(ap);
        }
        if (use_errno) {
                if (*basedir != '\0' || *file != '\0' || format != NULL)
                        fputs(": ", stderr);
                perror(NULL);
        } else
                fputc('\n', stderr);
}