nss/nss_db/db-alias.c

   1 /* Mail alias file parser in nss_db module.
   2    Copyright (C) 1996 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 <aliases.h>
  22 #include <alloca.h>
  23 #include <ctype.h>
  24 #include <db.h>
  25 #include <errno.h>
  26 #include <fcntl.h>
  27 #include <libc-lock.h>
  28 #include <paths.h>
  29 #include <string.h>
  30
  31 #include "nsswitch.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 DB *db;
  39 static int keep_db;
  40 static unsigned int entidx;     /* Index for `getaliasent_r'. */
  41
  42 /* Open database file if not already opened.  */
  43 static enum nss_status
  44 internal_setent (int stayopen)
  45 {
  46   enum nss_status status = NSS_STATUS_SUCCESS;
  47
  48   if (db == NULL)
  49     {
  50       db = dbopen (_PATH_VARDB "aliases.db", O_RDONLY, 0, DB_BTREE, NULL);
  51
  52       if (db == NULL)
  53         status = NSS_STATUS_UNAVAIL;
  54     }
  55
  56   /* Remember STAYOPEN flag.  */
  57   if (db != NULL)
  58     keep_db |= stayopen;
  59
  60   return status;
  61 }
  62
  63
  64 /* Thread-safe, exported version of that.  */
  65 enum nss_status
  66 _nss_db_setaliasent (int stayopen)
  67 {
  68   enum nss_status status;
  69
  70   __libc_lock_lock (lock);
  71
  72   status = internal_setent (stayopen);
  73
  74   /* Reset the sequential index.  */
  75   entidx = 0;
  76
  77   __libc_lock_unlock (lock);
  78
  79   return status;
  80 }
  81
  82
  83 /* Close the database file.  */
  84 static void
  85 internal_endent (void)
  86 {
  87   if (db != NULL)
  88     {
  89       (*db->close) (db);
  90       db = NULL;
  91     }
  92 }
  93
  94
  95 /* Thread-safe, exported version of that.  */
  96 enum nss_status
  97 _nss_db_endaliasent (void)
  98 {
  99   __libc_lock_lock (lock);
 100
 101   internal_endent ();
 102
 103   /* Reset STAYOPEN flag.  */
 104   keep_db = 0;
 105
 106   __libc_lock_unlock (lock);
 107
 108   return NSS_STATUS_SUCCESS;
 109 }
 110 \f
 111 /* We provide the parse function here.  The parser in libnss_files
 112    cannot be used.  The generation of the db file already resolved all
 113    :include: statements so we simply have to parse the list and store
 114    the result.  */
 115 static enum nss_status
 116 lookup (const DBT *key, struct aliasent *result, char *buffer,
 117             size_t buflen)
 118 {
 119   enum nss_status status;
 120   DBT value;
 121
 122   /* Open the database.  */
 123   status = internal_setent (keep_db);
 124   if (status != NSS_STATUS_SUCCESS)
 125     return status;
 126
 127   if ((*db->get) (db, key, &value, 0) == 0)
 128     {
 129       const char *src = value.data;
 130
 131       result->alias_members_len = 0;
 132
 133       /* We now have to fill the BUFFER with all the information. */
 134       if (buflen < key->size + 1)
 135         {
 136         no_more_room:
 137           __set_errno (ERANGE);
 138           return NSS_STATUS_TRYAGAIN;
 139         }
 140
 141       if (status == NSS_STATUS_SUCCESS)
 142         {
 143           char *cp;
 144           size_t cnt;
 145
 146           buffer = stpncpy (buffer, key->data, key->size) + 1;
 147           buflen -= key->size + 1;
 148
 149           while (*src != '\0')
 150             {
 151               const char *end, *upto;
 152               while (isspace (*src))
 153                 ++src;
 154
 155               end = strchr (src, ',');
 156               if (end == NULL)
 157                 end = strchr (src, '\0');
 158               for (upto = end; upto > src && isspace (upto[-1]); --upto);
 159
 160               if (upto != src)
 161                 {
 162                   if ((upto - src) + __alignof__ (char *) > buflen)
 163                     goto no_more_room;
 164                   buffer = stpncpy (buffer, src, upto - src) + 1;
 165                   buflen -= (upto - src) + __alignof (char *);
 166                   ++result->alias_members_len;
 167                 }
 168               src = end + (*end != '\0');
 169             }
 170
 171           /* Now prepare the return.  Provide string pointers for the
 172              currently selected aliases.  */
 173
 174           /* Adjust the pointer so it is aligned for storing pointers.  */
 175           buffer += __alignof__ (char *) - 1;
 176           buffer -= ((buffer - (char *) 0) % __alignof__ (char *));
 177           result->alias_members = (char **) buffer;
 178
 179           /* Compute addresses of alias entry strings.  */
 180           cp = result->alias_name;
 181           for (cnt = 0; cnt < result->alias_members_len; ++cnt)
 182             {
 183               cp = strchr (cp, '\0') + 1;
 184               result->alias_members[cnt] = cp;
 185             }
 186
 187           status = (result->alias_members_len == 0
 188                     ? NSS_STATUS_RETURN : NSS_STATUS_SUCCESS);
 189         }
 190     }
 191   else
 192     status = NSS_STATUS_NOTFOUND;
 193
 194   if (! keep_db)
 195     internal_endent ();
 196
 197   return status;
 198 }
 199 \f
 200 enum nss_status
 201 _nss_db_getaliasent_r (struct aliasent *result, char *buffer, size_t buflen)
 202 {
 203   /* Return next entry in host file.  */
 204   enum nss_status status;
 205   char buf[20];
 206   DBT key;
 207
 208   __libc_lock_lock (lock);
 209   key.size = 1 + snprintf (key.data = buf, sizeof buf, "0%u", entidx++);
 210   status = lookup (&key, result, buffer, buflen);
 211   __libc_lock_unlock (lock);
 212
 213   return status;
 214 }
 215
 216
 217 enum nss_status
 218 _nss_db_getaliasbyname_r (const char *name, struct aliasent *result,
 219                           char *buffer, size_t buflen)
 220 {
 221   DBT key;
 222   enum nss_status status;
 223
 224   key.size = 1 + strlen (name);
 225
 226   key.data = __alloca (key.size);
 227   ((char *) key.data)[0] = '.';
 228   memcpy (&((char *) key.data)[1], name, key.size - 1);
 229
 230   __libc_lock_lock (lock);
 231   status = lookup (&key, result, buffer, buflen);
 232   __libc_lock_unlock (lock);
 233
 234   return status;
 235 }