/*-
 * Copyright (c) 2007 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Brian Ginsbach.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>

#ifndef lint
__RCSID("$NetBSD: newgrp.c,v 1.7 2011/09/16 15:39:27 joerg Exp $");
#endif /* not lint */

#include <sys/param.h>
#include <sys/types.h>

#include <err.h>
#include <grp.h>
#include <libgen.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifdef LOGIN_CAP
#include <login_cap.h>
#endif

#include "grutil.h"

__dead static void
usage(void)
{
        (void)fprintf(stderr, "usage: %s [-l] [group]\n", getprogname());
        exit(EXIT_FAILURE);
}

int
main(int argc, char *argv[])
{
        extern char **environ;
        struct passwd *pwd;
        int c, lflag;
        char *shell, sbuf[MAXPATHLEN + 2];
        uid_t uid;
#ifdef LOGIN_CAP
        login_cap_t *lc;
        u_int flags = LOGIN_SETUSER;
#endif

        uid = getuid();
        pwd = getpwuid(uid);
        if (pwd == NULL)
                errx(EXIT_FAILURE, "who are you?");

#ifdef LOGIN_CAP
        if ((lc = login_getclass(pwd->pw_class)) == NULL)
                errx(EXIT_FAILURE, "%s: unknown login class", pwd->pw_class);
#endif

        (void)setprogname(argv[0]);
        lflag = 0;
        while ((c = getopt(argc, argv, "-l")) != -1) {
                switch (c) {
                case '-':
                case 'l':
                        if (lflag)
                                usage();
                        lflag = 1;
                        break;
                default:
                        usage();
                        break;
                }
        }

        argc -= optind;
        argv += optind;

        if (argc > 0) {
#if 0
                pwd->pw_gid = newgrp(*argv, pwd);
                addgrp(pwd->pw_gid);
                if (setgid(pwd->pw_gid) < 0)
                        err(1, "setgid");
#endif
#ifdef LOGIN_CAP
                addgroup(lc, *argv, pwd, getuid(), "Password:");
#else
                addgroup(*argv, pwd, getuid(), "Password:");
#endif
        } else {
#ifdef LOGIN_CAP
                flags |= LOGIN_SETGROUP;
#else
                if (initgroups(pwd->pw_name, pwd->pw_gid) == -1)
                        err(EXIT_FAILURE, "initgroups");
                if (setgid(pwd->pw_gid) == -1)
                        err(EXIT_FAILURE, "setgid");
#endif
        }

#ifdef LOGIN_CAP
        if (setusercontext(lc, pwd, uid, flags) == -1)
                err(EXIT_FAILURE, "setusercontext");
        if (!lflag)
                login_close(lc);
#else
        if (setuid(pwd->pw_uid) == -1)
                err(EXIT_FAILURE, "setuid");
#endif

        if (*pwd->pw_shell == '\0') {
#ifdef TRUST_ENV_SHELL
                shell = getenv("SHELL");
                if (shell != NULL)
                        pwd->pw_shell = shell;
                else
#endif
                        pwd->pw_shell = __UNCONST(_PATH_BSHELL);
        }

        shell = pwd->pw_shell;

        if (lflag) {
                char *term;
#ifdef KERBEROS
                char *krbtkfile;
#endif

                if (chdir(pwd->pw_dir) == -1)
                        warn("%s", pwd->pw_dir);

                term = getenv("TERM");
#ifdef KERBEROS
                krbtkfile = getenv("KRBTKFILE");
#endif

                /* create an empty environment */
                if ((environ = malloc(sizeof(char *))) == NULL)
                        err(EXIT_FAILURE, NULL);
                environ[0] = NULL;
#ifdef LOGIN_CAP
                if (setusercontext(lc, pwd, uid, LOGIN_SETENV | LOGIN_SETPATH) == -1)
                        err(EXIT_FAILURE, "setusercontext");
                login_close(lc);
#else
                (void)setenv("PATH", _PATH_DEFPATH, 1);
#endif
                if (term != NULL)
                        (void)setenv("TERM", term, 1);
#ifdef KERBEROS
                if (krbtkfile != NULL)
                        (void)setenv("KRBTKFILE", krbtkfile, 1);
#endif

                (void)setenv("LOGNAME", pwd->pw_name, 1);
                (void)setenv("USER", pwd->pw_name, 1);
                (void)setenv("HOME", pwd->pw_dir, 1);
                (void)setenv("SHELL", pwd->pw_shell, 1);

                sbuf[0] = '-';
                (void)strlcpy(sbuf + 1, basename(pwd->pw_shell),
                              sizeof(sbuf) - 1);
                shell = sbuf;
        }

        (void)execl(pwd->pw_shell, shell, NULL);
        err(EXIT_FAILURE, "%s", pwd->pw_shell);
        /* NOTREACHED */
}