nis/nis_local_names.c

   1 /* Copyright (c) 1997-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <string.h>
  20 #include <unistd.h>
  21 #include <libintl.h>
  22 #include <rpcsvc/nis.h>
  23 #include <shlib-compat.h>
  24
  25 nis_name
  26 nis_local_group (void)
  27 {
  28   static char __nisgroup[NIS_MAXNAMELEN + 1];
  29
  30   char *cptr;
  31   if (__nisgroup[0] == '\0'
  32       && (cptr = getenv ("NIS_GROUP")) != NULL
  33       && cptr[0] != '\0'
  34       && strlen (cptr) < NIS_MAXNAMELEN)
  35     {
  36       char *cp = stpcpy (__nisgroup, cptr);
  37
  38       if (cp[-1] != '.')
  39         {
  40           cptr = nis_local_directory ();
  41           if ((cp - __nisgroup) + strlen (cptr) + 1 < NIS_MAXNAMELEN)
  42             {
  43               *cp++ = '.';
  44               strcpy (cp, cptr);
  45             }
  46           else
  47             __nisgroup[0] = '\0';
  48         }
  49     }
  50
  51   return __nisgroup;
  52 }
  53 libnsl_hidden_nolink_def (nis_local_group, GLIBC_2_1)
  54
  55 nis_name
  56 nis_local_directory (void)
  57 {
  58   static char __nisdomainname[NIS_MAXNAMELEN + 1];
  59
  60   if (__nisdomainname[0] == '\0')
  61     {
  62       if (getdomainname (__nisdomainname, NIS_MAXNAMELEN) < 0)
  63         __nisdomainname[0] = '\0';
  64       else
  65         {
  66           char *cp = strchr (__nisdomainname, '\0');
  67
  68           /* Missing trailing dot? */
  69           if (cp[-1] != '.')
  70             {
  71               *cp++ = '.';
  72               *cp = '\0';
  73             }
  74         }
  75     }
  76
  77   return __nisdomainname;
  78 }
  79 libnsl_hidden_nolink_def (nis_local_directory, GLIBC_2_1)
  80
  81 nis_name
  82 nis_local_principal (void)
  83 {
  84   static char __principal[NIS_MAXNAMELEN + 1];
  85
  86   if (__principal[0] == '\0')
  87     {
  88       char buf[NIS_MAXNAMELEN + 1];
  89       nis_result *res;
  90       uid_t uid = geteuid ();
  91
  92       if (uid != 0)
  93         {
  94           int len = snprintf (buf, NIS_MAXNAMELEN - 1,
  95                               "[auth_name=%d,auth_type=LOCAL],cred.org_dir.%s",
  96                               uid, nis_local_directory ());
  97
  98           if (len >= NIS_MAXNAMELEN - 1)
  99             nobody:
 100             /* XXX The buffer is too small.  Can this happen???  */
 101             return strcpy (__principal, "nobody");
 102
 103           if (buf[len - 1] != '.')
 104             {
 105               buf[len++] = '.';
 106               buf[len] = '\0';
 107             }
 108
 109           res = nis_list (buf, USE_DGRAM + NO_AUTHINFO + FOLLOW_LINKS
 110                           + FOLLOW_PATH, NULL, NULL);
 111
 112           if (res == NULL)
 113             goto nobody;
 114
 115           if (NIS_RES_STATUS (res) == NIS_SUCCESS)
 116             {
 117               if (res->objects.objects_len > 1)
 118                 {
 119                   /* More than one principal with same uid?  something
 120                      wrong with cred table.  Should be unique.  Warn user
 121                      and continue.  */
 122                   printf (_("\
 123 LOCAL entry for UID %d in directory %s not unique\n"),
 124                           uid, nis_local_directory ());
 125                 }
 126               strcpy (__principal, ENTRY_VAL (res->objects.objects_val, 0));
 127               nis_freeresult (res);
 128               return __principal;
 129             }
 130           else
 131             {
 132               nis_freeresult (res);
 133               goto nobody;
 134             }
 135         }
 136       else
 137         return strcpy (__principal, nis_local_host ());
 138
 139       /* Should be never reached */
 140       goto nobody;
 141     }
 142   return __principal;
 143 }
 144 libnsl_hidden_nolink_def (nis_local_principal, GLIBC_2_1)
 145
 146 nis_name
 147 nis_local_host (void)
 148 {
 149   static char __nishostname[NIS_MAXNAMELEN + 1];
 150
 151   if (__nishostname[0] == '\0')
 152     {
 153       if (gethostname (__nishostname, NIS_MAXNAMELEN) < 0)
 154         __nishostname[0] = '\0';
 155       else
 156         {
 157           char *cp = strchr (__nishostname, '\0');
 158           int len = cp - __nishostname;
 159
 160           /* Hostname already fully qualified? */
 161           if (cp[-1] == '.')
 162             return __nishostname;
 163
 164           nis_name local_directory = nis_local_directory ();
 165           size_t local_directory_len = strlen (local_directory);
 166           if (len + 1 + local_directory_len > NIS_MAXNAMELEN)
 167             {
 168               __nishostname[0] = '\0';
 169               return __nishostname;
 170             }
 171
 172           /* We have enough space in __nishostname with length of
 173              (NIS_MAXNAMELEN + 1) for
 174              hostname + '.' + directory-name + '\0'.  */
 175           *cp++ = '.';
 176           memcpy (cp, local_directory, local_directory_len + 1);
 177         }
 178     }
 179
 180   return __nishostname;
 181 }
 182 libnsl_hidden_nolink_def (nis_local_host, GLIBC_2_1)