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/* Common code for DB-based databases in nss_db module.
Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <db.h>
#include <fcntl.h>
#include <libc-lock.h>
#include "nsswitch.h"
/* These symbols are defined by the including source file:
ENTNAME -- database name of the structure and functions (hostent, pwent).
STRUCTURE -- struct name, define only if not ENTNAME (passwd, group).
DATABASE -- database file name, ("hosts", "passwd")
NEED_H_ERRNO - defined iff an arg `int *herrnop' is used.
*/
#define ENTNAME_r CONCAT(ENTNAME,_r)
#include <paths.h>
#define DBFILE _PATH_VARDB DATABASE ".db"
#ifdef NEED_H_ERRNO
#define H_ERRNO_PROTO , int *herrnop
#define H_ERRNO_ARG , herrnop
#define H_ERRNO_SET(val) (*herrnop = (val))
#else
#define H_ERRNO_PROTO
#define H_ERRNO_ARG
#define H_ERRNO_SET(val) ((void) 0)
#endif
/* Locks the static variables in this file. */
__libc_lock_define_initialized (static, lock)
/* Maintenance of the shared handle open on the database. */
static DB *db;
static int keep_db;
static unsigned int entidx; /* Index for `getENTNAME'. */
/* Open database file if not already opened. */
static enum nss_status
internal_setent (int stayopen)
{
enum nss_status status = NSS_STATUS_SUCCESS;
if (db == NULL)
{
db = dbopen (DBFILE, O_RDONLY, 0, DB_BTREE, NULL);
if (db == NULL)
status = NSS_STATUS_UNAVAIL;
}
/* Remember STAYOPEN flag. */
if (db != NULL)
keep_db |= stayopen;
return status;
}
/* Thread-safe, exported version of that. */
enum nss_status
CONCAT(_nss_db_set,ENTNAME) (int stayopen)
{
enum nss_status status;
__libc_lock_lock (lock);
status = internal_setent (stayopen);
/* Reset the sequential index. */
entidx = 0;
__libc_lock_unlock (lock);
return status;
}
/* Close the database file. */
static void
internal_endent (void)
{
if (db != NULL)
{
(*db->close) (db);
db = NULL;
}
}
/* Thread-safe, exported version of that. */
enum nss_status
CONCAT(_nss_db_end,ENTNAME) (void)
{
__libc_lock_lock (lock);
internal_endent ();
/* Reset STAYOPEN flag. */
keep_db = 0;
__libc_lock_unlock (lock);
return NSS_STATUS_SUCCESS;
}
/* Do a database lookup for KEY. */
static enum nss_status
lookup (const DBT *key, struct STRUCTURE *result,
void *buffer, int buflen H_ERRNO_PROTO)
{
enum nss_status status;
DBT value;
/* Open the database. */
status = internal_setent (keep_db);
if (status != NSS_STATUS_SUCCESS)
return status;
/* Succeed iff it matches a value that parses correctly. */
status = (((*db->get) (db, key, &value, 0) == 0 &&
parse_line (value.data, result, buffer, buflen))
? NSS_STATUS_SUCCESS : NSS_STATUS_NOTFOUND);
if (! keep_db)
internal_endent ();
return status;
}
/* Macro for defining lookup functions for this DB-based database.
NAME is the name of the lookup; e.g. `pwnam'.
KEYPATTERN gives `printf' args to construct a key string;
e.g. `(".%s", name)'.
KEYSIZE gives the allocation size of a buffer to construct it in;
e.g. `1 + strlen (name)'.
PROTO describes the arguments for the lookup key;
e.g. `const char *name'.
BREAK_IF_MATCH is ignored, but used by ../nss_files/files-XXX.c. */
#define DB_LOOKUP(name, keysize, keypattern, break_if_match, proto...) \
enum nss_status \
_nss_db_get##name##_r (proto, \
struct STRUCTURE *result, \
char *buffer, int buflen H_ERRNO_PROTO) \
{ \
DBT key; \
enum nss_status status; \
const size_t size = (keysize); \
key.data = __alloca (size); \
key.size = KEYPRINTF keypattern; \
__libc_lock_lock (lock); \
status = lookup (&key, result, buffer, buflen H_ERRNO_ARG); \
__libc_lock_unlock (lock); \
return status; \
}
#define KEYPRINTF(pattern, args...) snprintf (key.data, size, pattern ,##args)
/* Return the next entry from the database file, doing locking. */
enum nss_status
CONCAT(_nss_db_get,ENTNAME_r) (struct STRUCTURE *result,
char *buffer, int buflen H_ERRNO_PROTO)
{
/* Return next entry in host file. */
enum nss_status status;
char buf[20];
DBT key;
__libc_lock_lock (lock);
key.size = 1 + snprintf (key.data = buf, sizeof buf, "0%u", entidx++);
status = lookup (&key, result, buffer, buflen H_ERRNO_ARG);
__libc_lock_unlock (lock);
return status;
}
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