usr/src/lib/libc/port/gen/getlogin.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 2013 Gary Mills
  24  *
  25  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  26  * Use is subject to license terms.
  27  */
  28
  29 /*      Copyright (c) 1988 AT&T */
  30 /*        All Rights Reserved   */
  31
  32 #pragma weak _getlogin = getloginx
  33 #pragma weak _getlogin_r = getloginx_r
  34
  35 #include "lint.h"
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38 #include <fcntl.h>
  39 #include <string.h>
  40 #include <stdlib.h>
  41 #include <limits.h>
  42 #include "utmpx.h"
  43 #include <unistd.h>
  44 #include <errno.h>
  45 #include <thread.h>
  46 #include <synch.h>
  47 #include <mtlib.h>
  48 #include "tsd.h"
  49
  50 /* Revert the renames done in unistd.h */
  51 #ifdef  __PRAGMA_REDEFINE_EXTNAME
  52 #pragma redefine_extname        getlogint       getlogin
  53 #pragma redefine_extname        getlogint_r     getlogin_r
  54 #pragma redefine_extname        __posix_getlogint_r     __posix_getlogin_r
  55 #else   /* __PRAGMA_REDEFINE_EXTNAME */
  56 #ifdef  getlogin
  57 #undef  getlogin
  58 #endif  /* getlogin */
  59 #ifdef  getlogin_r
  60 #undef  getlogin_r
  61 #endif  /* getlogin_r */
  62 #ifdef  __posix_getlogin_r
  63 #undef  __posix_getlogin_r
  64 #endif  /* __posix_getlogin_r */
  65 #define getlogint       getlogin
  66 #define getlogint_r     getlogin_r
  67 #define __posix_getlogint_r     __posix_getlogin_r
  68 #endif  /* __PRAGMA_REDEFINE_EXTNAME */
  69 extern char *getlogint(void);
  70 extern char *getlogint_r(char *, int);
  71 extern int __posix_getlogint_r(char *, int);
  72
  73 /*
  74  * Use the full length of a login name.
  75  * The utmpx interface provides for a 32 character login name.
  76  */
  77 #define NMAX    (sizeof (((struct utmpx *)0)->ut_user))
  78
  79 /*
  80  * Common function
  81  */
  82 static char *
  83 getl_r_common(char *answer, size_t namelen, size_t maxlen)
  84 {
  85         int             uf;
  86         off64_t         me;
  87         struct futmpx   ubuf;
  88         size_t          ulen;
  89
  90         if ((me = (off64_t)ttyslot()) < 0)
  91                 return (NULL);
  92         if ((uf = open64(UTMPX_FILE, 0)) < 0)
  93                 return (NULL);
  94         (void) lseek64(uf, me * sizeof (ubuf), SEEK_SET);
  95         if (read(uf, &ubuf, sizeof (ubuf)) != sizeof (ubuf)) {
  96                 (void) close(uf);
  97                 return (NULL);
  98         }
  99         (void) close(uf);
 100         if (ubuf.ut_user[0] == '\0')
 101                 return (NULL);
 102
 103         /* Insufficient buffer size */
 104         ulen = strnlen(ubuf.ut_user, maxlen);
 105         if (namelen <= ulen) {
 106                 errno = ERANGE;
 107                 return (NULL);
 108         }
 109
 110         /*
 111          * While the interface to getlogin_r says that a user should supply a
 112          * buffer with at least LOGIN_NAME_MAX bytes, we shouldn't assume they
 113          * have, especially since we've been supplied with its actual size.
 114          * Doing otherwise is just asking us to corrupt memory (and has in the
 115          * past).
 116          */
 117         (void) strncpy(answer, ubuf.ut_user, ulen);
 118         answer[ulen] = '\0';
 119         return (answer);
 120 }
 121
 122 /*
 123  * POSIX.1c Draft-6 version of the function getlogin_r.
 124  * It was implemented by Solaris 2.3.
 125  */
 126 char *
 127 getlogint_r(char *answer, int namelen)
 128 {
 129         return (getl_r_common(answer, (size_t)namelen, LOGNAME_MAX_TRAD));
 130 }
 131
 132 /*
 133  * POSIX.1c standard version of the function getlogin_r.
 134  * User gets it via static getlogin_r from the header file.
 135  */
 136 int
 137 __posix_getlogint_r(char *name, int namelen)
 138 {
 139         int nerrno = 0;
 140         int oerrno = errno;
 141
 142         errno = 0;
 143         if (getl_r_common(name, (size_t)namelen, LOGNAME_MAX_TRAD) == NULL) {
 144                 if (errno == 0)
 145                         nerrno = EINVAL;
 146                 else
 147                         nerrno = errno;
 148         }
 149         errno = oerrno;
 150         return (nerrno);
 151 }
 152
 153 char *
 154 getlogint(void)
 155 {
 156         char *answer = tsdalloc(_T_LOGIN, LOGIN_NAME_MAX_TRAD, NULL);
 157
 158         if (answer == NULL)
 159                 return (NULL);
 160         return (getl_r_common(answer, LOGIN_NAME_MAX_TRAD, LOGNAME_MAX_TRAD));
 161 }
 162
 163 /*
 164  * POSIX.1c Draft-6 version of the function getlogin_r.
 165  * It was implemented by Solaris 2.3.
 166  * For extended login names, selected by redefine_extname in unistd.h.
 167  */
 168 char *
 169 getloginx_r(char *answer, int namelen)
 170 {
 171         return (getl_r_common(answer, (size_t)namelen, NMAX));
 172 }
 173
 174 /*
 175  * POSIX.1c standard version of the function getlogin_r.
 176  * User gets it via static getlogin_r from the header file.
 177  * For extended login names, selected by redefine_extname in unistd.h.
 178  */
 179 int
 180 __posix_getloginx_r(char *name, int namelen)
 181 {
 182         int nerrno = 0;
 183         int oerrno = errno;
 184
 185         errno = 0;
 186         if (getl_r_common(name, (size_t)namelen, NMAX) == NULL) {
 187                 if (errno == 0)
 188                         nerrno = EINVAL;
 189                 else
 190                         nerrno = errno;
 191         }
 192         errno = oerrno;
 193         return (nerrno);
 194 }
 195
 196 /*
 197  * For extended login names, selected by redefine_extname in unistd.h.
 198  */
 199 char *
 200 getloginx(void)
 201 {
 202         char *answer = tsdalloc(_T_LOGIN, LOGIN_NAME_MAX, NULL);
 203
 204         if (answer == NULL)
 205                 return (NULL);
 206         return (getl_r_common(answer, LOGIN_NAME_MAX, NMAX));
 207 }