nis/nss_nis/nis-alias.c

   1 /* Copyright (C) 1996-2018 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <nss.h>
  20 #include <ctype.h>
  21 #include <errno.h>
  22 #include <string.h>
  23 #include <aliases.h>
  24 #include <libc-lock.h>
  25 #include <rpcsvc/yp.h>
  26 #include <rpcsvc/ypclnt.h>
  27
  28 #include "nss-nis.h"
  29
  30 __libc_lock_define_initialized (static, lock)
  31
  32 static bool_t new_start = 1;
  33 static char *oldkey;
  34 static int oldkeylen;
  35
  36 static int
  37 _nss_nis_parse_aliasent (const char *key, char *alias, struct aliasent *result,
  38                          char *buffer, size_t buflen, int *errnop)
  39 {
  40   char *first_unused = buffer + strlen (alias) + 1;
  41   size_t room_left =
  42     buflen - (buflen % __alignof__ (char *)) - strlen (alias) - 2;
  43   char *line;
  44   char *cp;
  45
  46   result->alias_members_len = 0;
  47   *first_unused = '\0';
  48   first_unused++;
  49   strcpy (first_unused, key);
  50
  51   if (first_unused[room_left - 1] != '\0')
  52     {
  53       /* The line is too long for our buffer.  */
  54     no_more_room:
  55       *errnop = ERANGE;
  56       return -1;
  57     }
  58
  59   result->alias_name = first_unused;
  60
  61   /* Terminate the line for any case.  */
  62   cp = strpbrk (alias, "#\n");
  63   if (cp != NULL)
  64     *cp = '\0';
  65
  66   first_unused += strlen (result->alias_name) + 1;
  67   /* Adjust the pointer so it is aligned for
  68      storing pointers.  */
  69   first_unused += __alignof__ (char *) - 1;
  70   first_unused -= ((first_unused - (char *) 0) % __alignof__ (char *));
  71   result->alias_members = (char **) first_unused;
  72
  73   line = alias;
  74
  75   while (*line != '\0')
  76     {
  77       /* Skip leading blanks.  */
  78       while (isspace (*line))
  79         line++;
  80
  81       if (*line == '\0')
  82         break;
  83
  84       if (room_left < sizeof (char *))
  85           goto no_more_room;
  86       room_left -= sizeof (char *);
  87       result->alias_members[result->alias_members_len] = line;
  88
  89       while (*line != '\0' && *line != ',')
  90         line++;
  91
  92       if (line != result->alias_members[result->alias_members_len])
  93         {
  94           *line = '\0';
  95           line++;
  96           result->alias_members_len++;
  97         }
  98     }
  99   return result->alias_members_len == 0 ? 0 : 1;
 100 }
 101
 102 enum nss_status
 103 _nss_nis_setaliasent (void)
 104 {
 105   __libc_lock_lock (lock);
 106
 107   new_start = 1;
 108   if (oldkey != NULL)
 109     {
 110       free (oldkey);
 111       oldkey = NULL;
 112       oldkeylen = 0;
 113     }
 114
 115   __libc_lock_unlock (lock);
 116
 117   return NSS_STATUS_SUCCESS;
 118 }
 119 /* The 'endaliasent' function is identical.  */
 120 strong_alias (_nss_nis_setaliasent, _nss_nis_endaliasent)
 121
 122 static enum nss_status
 123 internal_nis_getaliasent_r (struct aliasent *alias, char *buffer,
 124                             size_t buflen, int *errnop)
 125 {
 126   char *domain;
 127
 128   if (__glibc_unlikely (yp_get_default_domain (&domain)))
 129     return NSS_STATUS_UNAVAIL;
 130
 131   alias->alias_local = 0;
 132
 133   /* Get the next entry until we found a correct one. */
 134   int parse_res;
 135   do
 136     {
 137       char *result;
 138       int len;
 139       char *outkey;
 140       int keylen;
 141       int yperr;
 142
 143       if (new_start)
 144         yperr = yp_first (domain, "mail.aliases", &outkey, &keylen, &result,
 145                           &len);
 146       else
 147         yperr = yp_next (domain, "mail.aliases", oldkey, oldkeylen, &outkey,
 148                          &keylen, &result, &len);
 149
 150       if (__glibc_unlikely (yperr != YPERR_SUCCESS))
 151         {
 152           enum nss_status retval = yperr2nss (yperr);
 153
 154           if (retval == NSS_STATUS_TRYAGAIN)
 155             *errnop = errno;
 156           return retval;
 157         }
 158
 159       if (__glibc_unlikely ((size_t) (len + 1) > buflen))
 160         {
 161           free (result);
 162           *errnop = ERANGE;
 163           return NSS_STATUS_TRYAGAIN;
 164         }
 165       char *p = strncpy (buffer, result, len);
 166       buffer[len] = '\0';
 167       while (isspace (*p))
 168         ++p;
 169       free (result);
 170
 171       parse_res = _nss_nis_parse_aliasent (outkey, p, alias, buffer,
 172                                            buflen, errnop);
 173       if (__glibc_unlikely (parse_res == -1))
 174         {
 175           free (outkey);
 176           *errnop = ERANGE;
 177           return NSS_STATUS_TRYAGAIN;
 178         }
 179
 180       free (oldkey);
 181       oldkey = outkey;
 182       oldkeylen = keylen;
 183       new_start = 0;
 184     }
 185   while (!parse_res);
 186
 187   return NSS_STATUS_SUCCESS;
 188 }
 189
 190 enum nss_status
 191 _nss_nis_getaliasent_r (struct aliasent *alias, char *buffer, size_t buflen,
 192                         int *errnop)
 193 {
 194   enum nss_status status;
 195
 196   __libc_lock_lock (lock);
 197
 198   status = internal_nis_getaliasent_r (alias, buffer, buflen, errnop);
 199
 200   __libc_lock_unlock (lock);
 201
 202   return status;
 203 }
 204
 205 enum nss_status
 206 _nss_nis_getaliasbyname_r (const char *name, struct aliasent *alias,
 207                            char *buffer, size_t buflen, int *errnop)
 208 {
 209   if (name == NULL)
 210     {
 211       *errnop = EINVAL;
 212       return NSS_STATUS_UNAVAIL;
 213     }
 214
 215   char *domain;
 216   if (__glibc_unlikely (yp_get_default_domain (&domain)))
 217     return NSS_STATUS_UNAVAIL;
 218
 219   size_t namlen = strlen (name);
 220   char *name2;
 221   int use_alloca = __libc_use_alloca (namlen + 1);
 222   if (use_alloca)
 223     name2 = __alloca (namlen + 1);
 224   else
 225     {
 226       name2 = malloc (namlen + 1);
 227       if (name2 == NULL)
 228         {
 229           *errnop = ENOMEM;
 230           return NSS_STATUS_TRYAGAIN;
 231         }
 232     }
 233
 234   /* Convert name to lowercase.  */
 235   size_t i;
 236   for (i = 0; i < namlen; ++i)
 237     name2[i] = _tolower (name[i]);
 238   name2[i] = '\0';
 239
 240   char *result;
 241   int len;
 242   int yperr = yp_match (domain, "mail.aliases", name2, namlen, &result, &len);
 243
 244   if (!use_alloca)
 245     free (name2);
 246
 247   if (__glibc_unlikely (yperr != YPERR_SUCCESS))
 248     {
 249       enum nss_status retval = yperr2nss (yperr);
 250
 251       if (retval == NSS_STATUS_TRYAGAIN)
 252         *errnop = errno;
 253       return retval;
 254     }
 255
 256   if (__glibc_unlikely ((size_t) (len + 1) > buflen))
 257     {
 258       free (result);
 259       *errnop = ERANGE;
 260       return NSS_STATUS_TRYAGAIN;
 261     }
 262
 263   char *p = strncpy (buffer, result, len);
 264   buffer[len] = '\0';
 265   while (isspace (*p))
 266     ++p;
 267   free (result);
 268
 269   alias->alias_local = 0;
 270   int parse_res = _nss_nis_parse_aliasent (name, p, alias, buffer, buflen,
 271                                            errnop);
 272   if (__glibc_unlikely (parse_res < 1))
 273     {
 274       if (parse_res == -1)
 275         return NSS_STATUS_TRYAGAIN;
 276       else
 277         return NSS_STATUS_NOTFOUND;
 278     }
 279
 280   return NSS_STATUS_SUCCESS;
 281 }