glibc-compat/nss_db/db-XXX.c

   1 /* Common code for DB-based databases 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
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <dlfcn.h>
  21 #include <fcntl.h>
  22 #include <bits/libc-lock.h>
  23 #include "nsswitch.h"
  24 #include "nss_db.h"
  25
  26 /* These symbols are defined by the including source file:
  27
  28    ENTNAME -- database name of the structure and functions (hostent, pwent).
  29    STRUCTURE -- struct name, define only if not ENTNAME (passwd, group).
  30    DATABASE -- database file name, ("hosts", "passwd")
  31
  32    NEED_H_ERRNO - defined iff an arg `int *herrnop' is used.
  33 */
  34
  35 #define ENTNAME_r       CONCAT(ENTNAME,_r)
  36
  37 #include <paths.h>
  38 #define DBFILE          _PATH_VARDB DATABASE ".db"
  39
  40 #ifdef NEED_H_ERRNO
  41 #define H_ERRNO_PROTO   , int *herrnop
  42 #define H_ERRNO_ARG     , herrnop
  43 #define H_ERRNO_SET(val) (*herrnop = (val))
  44 #else
  45 #define H_ERRNO_PROTO
  46 #define H_ERRNO_ARG
  47 #define H_ERRNO_SET(val) ((void) 0)
  48 #endif
  49
  50 /* Locks the static variables in this file.  */
  51 __libc_lock_define_initialized (static, lock)
  52 \f
  53 /* Maintenance of the shared handle open on the database.  */
  54
  55 static NSS_DB *db;
  56 static int keep_db;
  57 static int entidx;
  58
  59
  60 /* Open the database.  */
  61 enum nss_status
  62 CONCAT(_nss_db_set,ENTNAME) (int stayopen)
  63 {
  64   enum nss_status status;
  65
  66   __libc_lock_lock (lock);
  67
  68   status = internal_setent (DBFILE, &db);
  69
  70   /* Remember STAYOPEN flag.  */
  71   if (db != NULL)
  72     keep_db |= stayopen;
  73   /* Reset the sequential index.  */
  74   entidx = 0;
  75
  76   __libc_lock_unlock (lock);
  77
  78   return status;
  79 }
  80
  81
  82 /* Close it again.  */
  83 enum nss_status
  84 CONCAT(_nss_db_end,ENTNAME) (void)
  85 {
  86   __libc_lock_lock (lock);
  87
  88   internal_endent (&db);
  89
  90   /* Reset STAYOPEN flag.  */
  91   keep_db = 0;
  92
  93   __libc_lock_unlock (lock);
  94
  95   return NSS_STATUS_SUCCESS;
  96 }
  97 \f
  98 /* Do a database lookup for KEY.  */
  99 static enum nss_status
 100 lookup (DBT *key, struct STRUCTURE *result,
 101         void *buffer, int buflen H_ERRNO_PROTO)
 102 {
 103   char *p;
 104   enum nss_status status;
 105   int err;
 106   DBT value;
 107
 108   /* Open the database.  */
 109   if (db == NULL)
 110     {
 111       status = internal_setent (DBFILE, &db);
 112       if (status != NSS_STATUS_SUCCESS)
 113         {
 114           H_ERRNO_SET (NETDB_INTERNAL);
 115           return status;
 116         }
 117     }
 118
 119   /* Succeed iff it matches a value that parses correctly.  */
 120   value.flags = 0;
 121   err = DL_CALL_FCT (db->get, (db->db, NULL, key, &value, 0));
 122   if (err != 0)
 123     {
 124       if (err == db_notfound)
 125         {
 126           H_ERRNO_SET (HOST_NOT_FOUND);
 127           status = NSS_STATUS_NOTFOUND;
 128         }
 129       else
 130         {
 131           H_ERRNO_SET (NETDB_INTERNAL);
 132           status = NSS_STATUS_UNAVAIL;
 133         }
 134     }
 135   else if (buflen < value.size)
 136     {
 137       /* No room to copy the data to.  */
 138       __set_errno (ERANGE);
 139       H_ERRNO_SET (NETDB_INTERNAL);
 140       status = NSS_STATUS_TRYAGAIN;
 141     }
 142   else
 143     {
 144       /* Copy the result to a safe place.  */
 145       p = (char *) memcpy (buffer, value.data, value.size);
 146
 147       /* Skip leading blanks.  */
 148       while (isspace (*p))
 149         ++p;
 150
 151       err = parse_line (p, result, buffer, buflen);
 152
 153       if (err == 0)
 154         {
 155           /* If the key begins with '0' we are trying to get the next
 156              entry.  We want to ignore unparsable lines in this case.  */
 157           if (((char *) key->data)[0] == '0')
 158             {
 159               /* Super magical return value.  We need to tell our caller
 160                  that it should continue looping.  This value cannot
 161                  happen in other cases.  */
 162               status = NSS_STATUS_RETURN;
 163             }
 164           else
 165             {
 166               H_ERRNO_SET (HOST_NOT_FOUND);
 167               status = NSS_STATUS_NOTFOUND;
 168             }
 169         }
 170       else if (err < 0)
 171         {
 172           H_ERRNO_SET (NETDB_INTERNAL);
 173           status = NSS_STATUS_TRYAGAIN;
 174         }
 175       else
 176         status = NSS_STATUS_SUCCESS;
 177     }
 178
 179   if (! keep_db)
 180     internal_endent (&db);
 181
 182   return status;
 183 }
 184
 185
 186 /* Macro for defining lookup functions for this DB-based database.
 187
 188    NAME is the name of the lookup; e.g. `pwnam'.
 189
 190    KEYPATTERN gives `printf' args to construct a key string;
 191    e.g. `(".%s", name)'.
 192
 193    KEYSIZE gives the allocation size of a buffer to construct it in;
 194    e.g. `1 + strlen (name)'.
 195
 196    PROTO describes the arguments for the lookup key;
 197    e.g. `const char *name'.
 198
 199    BREAK_IF_MATCH is ignored, but used by ../nss_files/files-XXX.c.  */
 200
 201 #define DB_LOOKUP(name, keysize, keypattern, break_if_match, proto...)        \
 202 enum nss_status                                                               \
 203 _nss_db_get##name##_r (proto,                                                 \
 204                        struct STRUCTURE *result,                              \
 205                        char *buffer, size_t buflen H_ERRNO_PROTO)\
 206 {                                                                             \
 207   DBT key;                                                                    \
 208   enum nss_status status;                                                     \
 209   const size_t size = (keysize) + 1;                                          \
 210   key.data = __alloca (size);                                                 \
 211   key.size = KEYPRINTF keypattern;                                            \
 212   key.flags = 0;                                                              \
 213   __libc_lock_lock (lock);                                                    \
 214   status = lookup (&key, result, buffer, buflen H_ERRNO_ARG);                 \
 215   __libc_lock_unlock (lock);                                                  \
 216   return status;                                                              \
 217 }
 218
 219 #define KEYPRINTF(pattern, args...) snprintf (key.data, size, pattern ,##args)
 220 \f
 221
 222
 223
 224 /* Return the next entry from the database file, doing locking.  */
 225 enum nss_status
 226 CONCAT(_nss_db_get,ENTNAME_r) (struct STRUCTURE *result, char *buffer,
 227                                size_t buflen H_ERRNO_PROTO)
 228 {
 229   /* Return next entry in host file.  */
 230   enum nss_status status;
 231   char buf[20];
 232   DBT key;
 233
 234   __libc_lock_lock (lock);
 235
 236   /* Loop until we find a valid entry or hit EOF.  See above for the
 237      special meaning of the status value.  */
 238   do
 239     {
 240       key.size = snprintf (key.data = buf, sizeof buf, "0%u", entidx++);
 241       key.flags = 0;
 242       status = lookup (&key, result, buffer, buflen H_ERRNO_ARG);
 243       if (status == NSS_STATUS_TRYAGAIN
 244 #ifdef NEED_H_ERRNO
 245           && *herrnop == NETDB_INTERNAL
 246 #endif
 247           && errno == ERANGE)
 248         /* Give the user a chance to get the same entry with a larger
 249            buffer.  */
 250         --entidx;
 251     }
 252   while (status == NSS_STATUS_RETURN);
 253
 254   __libc_lock_unlock (lock);
 255
 256   return status;
 257 }