/*      $OpenBSD: kvm_mkdb.c,v 1.33 2021/10/24 21:24:18 deraadt Exp $   */

/*-
 * Copyright (c) 1990, 1993
 *      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/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>

#include <db.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <grp.h>

#include "extern.h"

__dead void usage(void);
int kvm_mkdb(int, const char *, char *, char *, gid_t, int);

HASHINFO openinfo = {
        4096,           /* bsize */
        128,            /* ffactor */
        1024,           /* nelem */
        2048 * 1024,    /* cachesize */
        NULL,           /* hash() */
        0               /* lorder */
};

int
main(int argc, char *argv[])
{
        struct rlimit rl;
        struct group *gr;
        gid_t kvm_gid = -1;
        int fd, rval, ch, verbose = 0;
        char *nlistpath, *nlistname;
        char dbdir[PATH_MAX];

        if (pledge("stdio rpath wpath cpath fattr getpw flock id unveil", NULL) == -1)
                err(1, "pledge");

        /* Try to use the kmem group to be able to fchown() in kvm_mkdb(). */
        if ((gr = getgrnam("kmem")) == NULL) {
                warn("can't find kmem group");
        } else {
                kvm_gid = gr->gr_gid;
                if (setresgid(kvm_gid, kvm_gid, kvm_gid) == -1)
                        err(1, "setresgid");
        }

        /* Increase our data size to the max if we can. */
        if (getrlimit(RLIMIT_DATA, &rl) == 0) {
                rl.rlim_cur = rl.rlim_max;
                if (setrlimit(RLIMIT_DATA, &rl) == -1)
                        warn("can't set rlimit data size");
        }

        if (pledge("stdio rpath wpath cpath fattr flock unveil", NULL) == -1)
                err(1, "pledge");

        strlcpy(dbdir, _PATH_VARDB, sizeof(dbdir));
        while ((ch = getopt(argc, argv, "vo:")) != -1)
                switch (ch) {
                case 'v':
                        verbose = 1;
                        break;
                case 'o':
                        rval = strlcpy(dbdir, optarg, sizeof(dbdir));
                        if (rval == 0 || rval + 1 >= sizeof(dbdir))
                                errx(1, "Invalid directory");
                        /* Make sure there is a '/' at the end of the path */
                        if (dbdir[strlen(dbdir) - 1] != '/')
                                strlcat(dbdir, "/", sizeof(dbdir));
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc > 1)
                usage();

        if (argc > 0) {
                if (unveil(argv[0], "r") == -1)
                        err(1, "unveil %s", argv[0]);
        } else {
                if (unveil(_PATH_UNIX, "r") == -1)
                        err(1, "unveil %s", _PATH_UNIX);
                if (unveil(_PATH_KSYMS, "r") == -1)
                        err(1, "unveil %s", _PATH_KSYMS);
        }
        if (unveil(dbdir, "rwc") == -1)
                err(1, "unveil %s", dbdir);
        if (pledge("stdio rpath wpath cpath fattr flock", NULL) == -1)
                err(1, "pledge");

        /* If no kernel specified use _PATH_KSYMS and fall back to _PATH_UNIX */
        if (argc > 0) {
                nlistpath = argv[0];
                nlistname = basename(nlistpath);
                if ((fd = open(nlistpath, O_RDONLY)) == -1)
                        err(1, "can't open %s", nlistpath);
                rval = kvm_mkdb(fd, dbdir, nlistpath, nlistname, kvm_gid,
                    verbose);
        } else {
                nlistname = basename(_PATH_UNIX);
                if ((fd = open((nlistpath = _PATH_KSYMS), O_RDONLY)) == -1 ||
                    (rval = kvm_mkdb(fd, dbdir, nlistpath, nlistname, kvm_gid,
                    verbose)) != 0) {
                        if (fd == -1) 
                                warnx("can't open %s", _PATH_KSYMS);
                        else
                                warnx("will try again using %s instead", _PATH_UNIX);
                        if ((fd = open((nlistpath = _PATH_UNIX), O_RDONLY)) == -1)
                                err(1, "can't open %s", nlistpath);
                        rval = kvm_mkdb(fd, dbdir, nlistpath, nlistname,
                            kvm_gid, verbose);
                }
        }
        exit(rval);
}

int
kvm_mkdb(int fd, const char *dbdir, char *nlistpath, char *nlistname, gid_t gid, 
    int verbose)
{
        DB *db;
        char dbtemp[PATH_MAX], dbname[PATH_MAX];
        int r;

        r = snprintf(dbtemp, sizeof(dbtemp), "%skvm_%s.tmp",
            dbdir, nlistname);
        if (r < 0 || r >= sizeof(dbtemp)) {
                warnx("Directory name too long");
                return (1);
        }
        r = snprintf(dbname, sizeof(dbname), "%skvm_%s.db",
            dbdir, nlistname);
        if (r < 0 || r >= sizeof(dbtemp)) {
                warnx("Directory name too long");
                return (1);
        }

        /* If the existing db file matches the currently running kernel, exit */
        if (testdb(dbname)) {
                if (verbose)
                        warnx("%s already up to date", dbname);
                return(0);
        } else if (verbose)
                warnx("rebuilding %s", dbname);

        (void)umask(0);
        db = dbopen(dbtemp, O_CREAT | O_EXLOCK | O_TRUNC | O_RDWR,
            S_IRUSR | S_IWUSR | S_IRGRP, DB_HASH, &openinfo);
        if (db == NULL) {
                warn("can't dbopen %s", dbtemp);
                return(1);
        }

        if (gid != -1 && fchown(db->fd(db), -1, gid) == -1) {
                warn("can't chown %s", dbtemp);
                (void)unlink(dbtemp);
                return(1);
        }

        if (create_knlist(nlistpath, fd, db) != 0) {
                warn("cannot determine executable type of %s", nlistpath);
                (void)unlink(dbtemp);
                return(1);
        }
        if (db->close(db)) {
                warn("can't dbclose %s", dbtemp);
                (void)unlink(dbtemp);
                return(1);
        }

        if (rename(dbtemp, dbname)) {
                warn("rename %s to %s", dbtemp, dbname);
                (void)unlink(dbtemp);
                return(1);
        }

        return(0);
}

__dead void
usage(void)
{
        (void)fprintf(stderr, "usage: kvm_mkdb [-v] [-o directory] [file]\n");
        exit(1);
}