lib/libc/gen/getlogin.c

   1 /*
   2  * Copyright (c) 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * $FreeBSD: src/lib/libc/gen/getlogin.c,v 1.4.2.1 2001/03/05 09:06:50 obrien Exp $
  34  * $DragonFly: src/lib/libc/gen/getlogin.c,v 1.4 2005/04/26 06:08:42 joerg Exp $
  35  *
  36  * @(#)getlogin.c       8.1 (Berkeley) 6/4/93
  37  */
  38
  39 #include <sys/param.h>
  40 #include <errno.h>
  41 #include <pwd.h>
  42 #include <utmp.h>
  43 #include <stdio.h>
  44 #include <string.h>
  45 #include <unistd.h>
  46 #include "namespace.h"
  47 #include <pthread.h>
  48 #include "un-namespace.h"
  49
  50 #include <libc_private.h>
  51
  52 #define THREAD_LOCK()   if (__isthreaded) _pthread_mutex_lock(&logname_mutex)
  53 #define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&logname_mutex)
  54
  55 extern int              _getlogin(char *, int);
  56
  57 int                     _logname_valid;         /* known to setlogin() */
  58 static pthread_mutex_t  logname_mutex = PTHREAD_MUTEX_INITIALIZER;
  59
  60 static char *
  61 getlogin_basic(int *status)
  62 {
  63         static char logname[MAXLOGNAME];
  64
  65         if (_logname_valid == 0) {
  66                 if (_getlogin(logname, sizeof(logname)) < 0) {
  67                         *status = errno;
  68                         return (NULL);
  69                 }
  70                 _logname_valid = 1;
  71         }
  72         *status = 0;
  73         return (*logname ? logname : NULL);
  74 }
  75
  76 char *
  77 getlogin(void)
  78 {
  79         char    *result;
  80         int     status;
  81
  82         THREAD_LOCK();
  83         result = getlogin_basic(&status);
  84         THREAD_UNLOCK();
  85         return (result);
  86 }
  87
  88 int
  89 getlogin_r(char *logname, int namelen)
  90 {
  91         char    *result;
  92         int     len;
  93         int     status;
  94
  95         THREAD_LOCK();
  96         result = getlogin_basic(&status);
  97         if (status == 0) {
  98                 if ((len = strlen(result) + 1) > namelen)
  99                         status = ERANGE;
 100                 else
 101                         strncpy(logname, result, len);
 102         }
 103         THREAD_UNLOCK();
 104         return (status);
 105 }