freebsd-dev/lib/libc/gen/getlogin.c
Marcel Moolenaar eef9f6d258 The getlogin_basic() function can return a 0 status with a NULL
pointer for the login name (result). Make sure to handle that
case properly. Improve robustness by checking namelen and then
nul-terminating the provided buffer to simplify subsequent logic.

Obtained from:	Juniper Networks, Inc.
MFC after:	1 week
2014-04-05 18:14:58 +00:00

107 lines
3.0 KiB
C

/*
* Copyright (c) 1988, 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.
* 4. 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getlogin.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <errno.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "namespace.h"
#include <pthread.h>
#include "un-namespace.h"
#include "libc_private.h"
#define THREAD_LOCK() if (__isthreaded) _pthread_mutex_lock(&logname_mutex)
#define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&logname_mutex)
extern int _getlogin(char *, int);
int _logname_valid __hidden; /* known to setlogin() */
static pthread_mutex_t logname_mutex = PTHREAD_MUTEX_INITIALIZER;
static char *
getlogin_basic(int *status)
{
static char logname[MAXLOGNAME];
if (_logname_valid == 0) {
if (_getlogin(logname, sizeof(logname)) < 0) {
*status = errno;
return (NULL);
}
_logname_valid = 1;
}
*status = 0;
return (*logname ? logname : NULL);
}
char *
getlogin(void)
{
char *result;
int status;
THREAD_LOCK();
result = getlogin_basic(&status);
THREAD_UNLOCK();
return (result);
}
int
getlogin_r(char *logname, int namelen)
{
char *result;
int len;
int status;
if (namelen < 1)
return (ERANGE);
logname[0] = '\0';
THREAD_LOCK();
result = getlogin_basic(&status);
if (status == 0 && result != NULL) {
len = strlen(result) + 1;
if (len > namelen)
status = ERANGE;
else
strncpy(logname, result, len);
}
THREAD_UNLOCK();
return (status);
}