nss/nss_db/db-alias.c

   1 /* Mail alias file parser in nss_db module.
   2    Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <aliases.h>
  22 #include <alloca.h>
  23 #include <ctype.h>
  24 #include <dlfcn.h>
  25 #include <errno.h>
  26 #include <bits/libc-lock.h>
  27 #include <paths.h>
  28 #include <string.h>
  29
  30 #include "nsswitch.h"
  31 #include "nss_db.h"
  32
  33 /* Locks the static variables in this file.  */
  34 __libc_lock_define_initialized (static, lock)
  35 \f
  36 /* Maintenance of the shared handle open on the database.  */
  37
  38 static NSS_DB *db;
  39 static int keep_db;
  40 static unsigned int entidx;     /* Index for `getaliasent_r'. */
  41
  42
  43 /* Open database.  */
  44 enum nss_status
  45 _nss_db_setaliasent (int stayopen)
  46 {
  47   enum nss_status status;
  48
  49   __libc_lock_lock (lock);
  50
  51   status = internal_setent (_PATH_VARDB "aliases.db", &db);
  52
  53   /* Remember STAYOPEN flag.  */
  54   if (db != NULL)
  55     keep_db |= stayopen;
  56
  57   /* Reset the sequential index.  */
  58   entidx = 0;
  59
  60   __libc_lock_unlock (lock);
  61
  62   return status;
  63 }
  64
  65
  66 /* Close it again.  */
  67 enum nss_status
  68 _nss_db_endaliasent (void)
  69 {
  70   __libc_lock_lock (lock);
  71
  72   internal_endent (&db);
  73
  74   /* Reset STAYOPEN flag.  */
  75   keep_db = 0;
  76
  77   __libc_lock_unlock (lock);
  78
  79   return NSS_STATUS_SUCCESS;
  80 }
  81 \f
  82 /* We provide the parse function here.  The parser in libnss_files
  83    cannot be used.  The generation of the db file already resolved all
  84    :include: statements so we simply have to parse the list and store
  85    the result.  */
  86 static enum nss_status
  87 lookup (DBT *key, struct aliasent *result, char *buffer,
  88         size_t buflen, int *errnop)
  89 {
  90   enum nss_status status;
  91   DBT value;
  92
  93   /* Open the database.  */
  94   if (db == NULL)
  95     {
  96       status = internal_setent (_PATH_VARDB "aliases.db", &db);
  97       if (status != NSS_STATUS_SUCCESS)
  98         {
  99           *errnop = errno;
 100           return status;
 101         }
 102     }
 103
 104   value.flags = 0;
 105   if (DL_CALL_FCT (db->get, (db->db, NULL, key, &value, 0)) == 0)
 106     {
 107       const char *src = value.data;
 108       char *cp;
 109       size_t cnt;
 110
 111       result->alias_members_len = 0;
 112
 113       /* We now have to fill the BUFFER with all the information. */
 114       if (buflen < key->size + 1)
 115         {
 116         no_more_room:
 117           *errnop = ERANGE;
 118           return NSS_STATUS_TRYAGAIN;
 119         }
 120
 121       buffer = stpncpy (buffer, key->data, key->size) + 1;
 122       buflen -= key->size + 1;
 123
 124       while (*src != '\0')
 125         {
 126           const char *end, *upto;
 127           while (isspace (*src))
 128             ++src;
 129
 130           end = strchr (src, ',');
 131           if (end == NULL)
 132             end = strchr (src, '\0');
 133           for (upto = end; upto > src && isspace (upto[-1]); --upto);
 134
 135           if (upto != src)
 136             {
 137               if ((upto - src) + __alignof__ (char *) > buflen)
 138                 goto no_more_room;
 139               buffer = stpncpy (buffer, src, upto - src) + 1;
 140               buflen -= (upto - src) + __alignof (char *);
 141               ++result->alias_members_len;
 142             }
 143           src = end + (*end != '\0');
 144         }
 145
 146       /* Now prepare the return.  Provide string pointers for the
 147          currently selected aliases.  */
 148
 149       /* Adjust the pointer so it is aligned for storing pointers.  */
 150       buffer += __alignof__ (char *) - 1;
 151       buffer -= ((buffer - (char *) 0) % __alignof__ (char *));
 152       result->alias_members = (char **) buffer;
 153
 154       /* Compute addresses of alias entry strings.  */
 155       cp = result->alias_name;
 156       for (cnt = 0; cnt < result->alias_members_len; ++cnt)
 157         {
 158           cp = strchr (cp, '\0') + 1;
 159           result->alias_members[cnt] = cp;
 160         }
 161
 162       status = (result->alias_members_len == 0
 163                 ? NSS_STATUS_RETURN : NSS_STATUS_SUCCESS);
 164     }
 165   else
 166     status = NSS_STATUS_NOTFOUND;
 167
 168   if (! keep_db)
 169     internal_endent (&db);
 170
 171   return status;
 172 }
 173 \f
 174 enum nss_status
 175 _nss_db_getaliasent_r (struct aliasent *result, char *buffer, size_t buflen,
 176                        int *errnop)
 177 {
 178   /* Return next entry in alias file.  */
 179   enum nss_status status;
 180   char buf[20];
 181   DBT key;
 182
 183   __libc_lock_lock (lock);
 184   key.size = snprintf (key.data = buf, sizeof buf, "0%u", entidx++);
 185   key.flags = 0;
 186   status = lookup (&key, result, buffer, buflen, errnop);
 187   if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
 188     /* Give the user a chance to get the same entry with a larger buffer.  */
 189     --entidx;
 190   __libc_lock_unlock (lock);
 191
 192   return status;
 193 }
 194
 195
 196 enum nss_status
 197 _nss_db_getaliasbyname_r (const char *name, struct aliasent *result,
 198                           char *buffer, size_t buflen, int *errnop)
 199 {
 200   DBT key;
 201   enum nss_status status;
 202
 203   key.size = 1 + strlen (name);
 204
 205   key.data = __alloca (key.size);
 206   ((char *) key.data)[0] = '.';
 207   memcpy (&((char *) key.data)[1], name, key.size - 1);
 208   key.flags = 0;
 209
 210   __libc_lock_lock (lock);
 211   status = lookup (&key, result, buffer, buflen, errnop);
 212   __libc_lock_unlock (lock);
 213
 214   return status;
 215 }