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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * $FreeBSD: src/lib/libc/gen/getlogin.c,v 1.4.2.1 2001/03/05 09:06:50 obrien Exp $
  30  *
  31  * @(#)getlogin.c       8.1 (Berkeley) 6/4/93
  32  */
  33
  34 #include <sys/param.h>
  35 #include <errno.h>
  36 #include <pwd.h>
  37 #include <utmp.h>
  38 #include <stdio.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41 #include "namespace.h"
  42 #include <pthread.h>
  43 #include "un-namespace.h"
  44
  45 #include "libc_private.h"
  46
  47 #define THREAD_LOCK()   if (__isthreaded) _pthread_mutex_lock(&logname_mutex)
  48 #define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&logname_mutex)
  49
  50 extern int              _getlogin(char *, int);
  51
  52 int                     _logname_valid;         /* known to setlogin() */
  53 static pthread_mutex_t  logname_mutex = PTHREAD_MUTEX_INITIALIZER;
  54
  55 static char *
  56 getlogin_basic(int *status)
  57 {
  58         static char logname[MAXLOGNAME];
  59
  60         if (_logname_valid == 0) {
  61                 if (_getlogin(logname, sizeof(logname)) < 0) {
  62                         *status = errno;
  63                         return (NULL);
  64                 }
  65                 _logname_valid = 1;
  66         }
  67         *status = 0;
  68         return (*logname ? logname : NULL);
  69 }
  70
  71 char *
  72 getlogin(void)
  73 {
  74         char    *result;
  75         int     status;
  76
  77         THREAD_LOCK();
  78         result = getlogin_basic(&status);
  79         THREAD_UNLOCK();
  80         return (result);
  81 }
  82
  83 int
  84 getlogin_r(char *logname, int namelen)
  85 {
  86         char    *result;
  87         int     len;
  88         int     status;
  89
  90         THREAD_LOCK();
  91         result = getlogin_basic(&status);
  92         if (status == 0) {
  93                 if ((len = strlen(result) + 1) > namelen)
  94                         status = ERANGE;
  95                 else
  96                         strncpy(logname, result, len);
  97         }
  98         THREAD_UNLOCK();
  99         return (status);
 100 }