freebsd-dev/libexec/ulog-helper/ulog-helper.c
Pedro F. Giffuni e6209940de libexec: adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.
2017-11-27 15:25:02 +00:00

100 lines
3.1 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2009 Ed Schouten <ed@FreeBSD.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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>
__FBSDID("$FreeBSD$");
#include <pwd.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <ulog.h>
/*
* This setuid helper utility writes user login records to disk.
* Unprivileged processes are not capable of writing records to utmpx,
* but we do want to allow this for pseudo-terminals. Because a file
* descriptor to a pseudo-terminal master device can only be obtained by
* processes using the pseudo-terminal, we expect such a descriptor on
* stdin.
*
* It uses the real user ID of the calling process to determine the
* username. It does allow users to log arbitrary hostnames.
*/
static const char *
get_username(void)
{
const struct passwd *pw;
const char *login;
uid_t uid;
/*
* Attempt to determine the username corresponding to this login
* session. First, validate the results of getlogin() against
* the password database. If getlogin() returns invalid data,
* return an arbitrary username corresponding to this uid.
*/
uid = getuid();
if ((login = getlogin()) != NULL && (pw = getpwnam(login)) != NULL &&
pw->pw_uid == uid)
return (login);
if ((pw = getpwuid(uid)) != NULL)
return (pw->pw_name);
return (NULL);
}
int
main(int argc, char *argv[])
{
const char *line, *user, *host;
/* Device line name. */
if ((line = ptsname(STDIN_FILENO)) == NULL)
return (EX_USAGE);
if ((argc == 2 || argc == 3) && strcmp(argv[1], "login") == 0) {
/* Username. */
user = get_username();
if (user == NULL)
return (EX_OSERR);
/* Hostname. */
host = argc == 3 ? argv[2] : NULL;
ulog_login(line, user, host);
return (EX_OK);
} else if (argc == 2 && strcmp(argv[1], "logout") == 0) {
ulog_logout(line);
return (EX_OK);
}
return (EX_USAGE);
}