lib/libc/gen/getlogin.c

   1 /*      $NetBSD: getlogin.c,v 1.15 2009/01/11 02:46:27 christos Exp $   */
   2
   3 /*-
   4  * Copyright (c) 2008 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  26  * POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /*
  30  * Copyright (c) 1988, 1993
  31  *      The Regents of the University of California.  All rights reserved.
  32  *
  33  * Redistribution and use in source and binary forms, with or without
  34  * modification, are permitted provided that the following conditions
  35  * are met:
  36  * 1. Redistributions of source code must retain the above copyright
  37  *    notice, this list of conditions and the following disclaimer.
  38  * 2. Redistributions in binary form must reproduce the above copyright
  39  *    notice, this list of conditions and the following disclaimer in the
  40  *    documentation and/or other materials provided with the distribution.
  41  * 3. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58 #include <sys/cdefs.h>
  59 #if defined(LIBC_SCCS) && !defined(lint)
  60 #if 0
  61 static char sccsid[] = "@(#)getlogin.c  8.1 (Berkeley) 6/4/93";
  62 #else
  63 __RCSID("$NetBSD: getlogin.c,v 1.15 2009/01/11 02:46:27 christos Exp $");
  64 #endif
  65 #endif /* LIBC_SCCS and not lint */
  66
  67 #include "namespace.h"
  68 #include <sys/param.h>
  69 #include <pwd.h>
  70 #include <utmp.h>
  71 #include <stdio.h>
  72 #include <string.h>
  73 #include <unistd.h>
  74 #include <errno.h>
  75 #include "reentrant.h"
  76 #include "extern.h"
  77
  78 #ifdef __weak_alias
  79 __weak_alias(getlogin,_getlogin)
  80 __weak_alias(getlogin_r,_getlogin_r)
  81 #if !defined(__minix)
  82 __weak_alias(setlogin,_setlogin)
  83 #endif /* !defined(__minix) */
  84 #endif
  85
  86 int     __logname_valid;                /* known to setlogin() */
  87 static char logname[MAXLOGNAME + 1];
  88
  89 #ifdef _REENTRANT
  90 static mutex_t  logname_mutex = MUTEX_INITIALIZER;
  91 #endif
  92
  93 char *
  94 getlogin(void)
  95 {
  96         char *rv;
  97
  98         mutex_lock(&logname_mutex);
  99         if (__logname_valid == 0) {
 100                 if (__getlogin(logname, sizeof(logname) - 1) < 0) {
 101                         mutex_unlock(&logname_mutex);
 102                         return ((char *)NULL);
 103                 }
 104                 __logname_valid = 1;
 105         }
 106         rv = (*logname ? logname : (char *)NULL);
 107         mutex_unlock(&logname_mutex);
 108
 109         return rv;
 110 }
 111
 112 int
 113 getlogin_r(char *name, size_t namelen)
 114 {
 115         size_t len;
 116         int rv;
 117
 118         mutex_lock(&logname_mutex);
 119         if (__logname_valid == 0) {
 120                 if (__getlogin(logname, sizeof(logname) - 1) < 0) {
 121                         rv = errno;
 122                         mutex_unlock(&logname_mutex);
 123                         return (rv);
 124                 }
 125                 __logname_valid = 1;
 126         }
 127         len = strlen(logname) + 1;
 128         if (len > namelen) {
 129                 rv = ERANGE;
 130         } else {
 131                 strncpy(name, logname, len);
 132                 rv = 0;
 133         }
 134         mutex_unlock(&logname_mutex);
 135
 136         return (rv);
 137 }
 138
 139 #if !defined(__minix)
 140 int
 141 setlogin(const char *name)
 142 {
 143         int retval;
 144
 145         retval = __setlogin(name);
 146         __logname_valid = 0;
 147
 148         return (retval);
 149 }
 150 #endif /* !defined(__minix) */