glibc-compat/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 Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    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    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include <glibc-compat/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)
  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         return status;
  99     }
 100
 101   value.flags = 0;
 102   if (DL_CALL_FCT (db->get, (db->db, NULL, key, &value, 0)) == 0)
 103     {
 104       const char *src = value.data;
 105       char *cp;
 106       size_t cnt;
 107
 108       result->alias_members_len = 0;
 109
 110       /* We now have to fill the BUFFER with all the information. */
 111       if (buflen < key->size + 1)
 112         {
 113         no_more_room:
 114           __set_errno (ERANGE);
 115           return NSS_STATUS_TRYAGAIN;
 116         }
 117
 118       buffer = stpncpy (buffer, key->data, key->size) + 1;
 119       buflen -= key->size + 1;
 120
 121       while (*src != '\0')
 122         {
 123           const char *end, *upto;
 124           while (isspace (*src))
 125             ++src;
 126
 127           end = strchr (src, ',');
 128           if (end == NULL)
 129             end = strchr (src, '\0');
 130           for (upto = end; upto > src && isspace (upto[-1]); --upto);
 131
 132           if (upto != src)
 133             {
 134               if ((upto - src) + __alignof__ (char *) > buflen)
 135                 goto no_more_room;
 136               buffer = stpncpy (buffer, src, upto - src) + 1;
 137               buflen -= (upto - src) + __alignof (char *);
 138               ++result->alias_members_len;
 139             }
 140           src = end + (*end != '\0');
 141         }
 142
 143       /* Now prepare the return.  Provide string pointers for the
 144          currently selected aliases.  */
 145
 146       /* Adjust the pointer so it is aligned for storing pointers.  */
 147       buffer += __alignof__ (char *) - 1;
 148       buffer -= ((buffer - (char *) 0) % __alignof__ (char *));
 149       result->alias_members = (char **) buffer;
 150
 151       /* Compute addresses of alias entry strings.  */
 152       cp = result->alias_name;
 153       for (cnt = 0; cnt < result->alias_members_len; ++cnt)
 154         {
 155           cp = strchr (cp, '\0') + 1;
 156           result->alias_members[cnt] = cp;
 157         }
 158
 159       status = (result->alias_members_len == 0
 160                 ? NSS_STATUS_RETURN : NSS_STATUS_SUCCESS);
 161     }
 162   else
 163     status = NSS_STATUS_NOTFOUND;
 164
 165   if (! keep_db)
 166     internal_endent (&db);
 167
 168   return status;
 169 }
 170 \f
 171 enum nss_status
 172 _nss_db_getaliasent_r (struct aliasent *result, char *buffer, size_t buflen)
 173 {
 174   /* Return next entry in alias file.  */
 175   enum nss_status status;
 176   char buf[20];
 177   DBT key;
 178
 179   __libc_lock_lock (lock);
 180   key.size = snprintf (key.data = buf, sizeof buf, "0%u", entidx++);
 181   key.flags = 0;
 182   status = lookup (&key, result, buffer, buflen);
 183   __libc_lock_unlock (lock);
 184
 185   return status;
 186 }
 187
 188
 189 enum nss_status
 190 _nss_db_getaliasbyname_r (const char *name, struct aliasent *result,
 191                           char *buffer, size_t buflen)
 192 {
 193   DBT key;
 194   enum nss_status status;
 195
 196   key.size = 1 + strlen (name);
 197
 198   key.data = __alloca (key.size);
 199   ((char *) key.data)[0] = '.';
 200   memcpy (&((char *) key.data)[1], name, key.size - 1);
 201   key.flags = 0;
 202
 203   __libc_lock_lock (lock);
 204   status = lookup (&key, result, buffer, buflen);
 205   __libc_lock_unlock (lock);
 206
 207   return status;
 208 }