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3d76e77847
1998-03-11 Ulrich Drepper <drepper@cygnus.com> * nss/nss_db/db-XXX.c (lookup): Copy data to safe place before parsing it.
292 lines
7.2 KiB
C
292 lines
7.2 KiB
C
/* Common code for DB-based databases in nss_db module.
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Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <db_185.h>
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#include <fcntl.h>
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#include <bits/libc-lock.h>
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#include "nsswitch.h"
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/* These symbols are defined by the including source file:
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ENTNAME -- database name of the structure and functions (hostent, pwent).
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STRUCTURE -- struct name, define only if not ENTNAME (passwd, group).
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DATABASE -- database file name, ("hosts", "passwd")
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NEED_H_ERRNO - defined iff an arg `int *herrnop' is used.
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*/
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#define ENTNAME_r CONCAT(ENTNAME,_r)
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#include <paths.h>
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#define DBFILE _PATH_VARDB DATABASE ".db"
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#ifdef NEED_H_ERRNO
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#define H_ERRNO_PROTO , int *herrnop
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#define H_ERRNO_ARG , herrnop
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#define H_ERRNO_SET(val) (*herrnop = (val))
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#else
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#define H_ERRNO_PROTO
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#define H_ERRNO_ARG
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#define H_ERRNO_SET(val) ((void) 0)
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#endif
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/* Locks the static variables in this file. */
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__libc_lock_define_initialized (static, lock)
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/* Maintenance of the shared handle open on the database. */
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static DB *db;
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static int keep_db;
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static unsigned int entidx; /* Index for `getENTNAME'. */
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/* Open database file if not already opened. */
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static enum nss_status
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internal_setent (int stayopen)
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{
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enum nss_status status = NSS_STATUS_SUCCESS;
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if (db == NULL)
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{
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db = __dbopen (DBFILE, O_RDONLY, 0, DB_BTREE, NULL);
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if (db == NULL)
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status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
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else
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{
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/* We have to make sure the file is `closed on exec'. */
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int result, flags;
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result = flags = fcntl ((*db->fd) (db), F_GETFD, 0);
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if (result >= 0)
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{
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flags |= FD_CLOEXEC;
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result = fcntl ((*db->fd) (db), F_SETFD, flags);
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}
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if (result < 0)
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{
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/* Something went wrong. Close the stream and return a
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failure. */
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(*db->close) (db);
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db = NULL;
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status = NSS_STATUS_UNAVAIL;
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}
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}
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}
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/* Remember STAYOPEN flag. */
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if (db != NULL)
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keep_db |= stayopen;
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return status;
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}
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/* Thread-safe, exported version of that. */
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enum nss_status
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CONCAT(_nss_db_set,ENTNAME) (int stayopen)
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{
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enum nss_status status;
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__libc_lock_lock (lock);
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status = internal_setent (stayopen);
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/* Reset the sequential index. */
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entidx = 0;
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__libc_lock_unlock (lock);
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return status;
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}
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/* Close the database file. */
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static void
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internal_endent (void)
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{
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if (db != NULL)
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{
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(*db->close) (db);
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db = NULL;
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}
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}
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/* Thread-safe, exported version of that. */
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enum nss_status
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CONCAT(_nss_db_end,ENTNAME) (void)
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{
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__libc_lock_lock (lock);
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internal_endent ();
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/* Reset STAYOPEN flag. */
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keep_db = 0;
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__libc_lock_unlock (lock);
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return NSS_STATUS_SUCCESS;
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}
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/* Do a database lookup for KEY. */
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static enum nss_status
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lookup (const DBT *key, struct STRUCTURE *result,
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void *buffer, size_t buflen, int *errnop H_ERRNO_PROTO)
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{
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char *p;
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enum nss_status status;
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int err;
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DBT value;
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/* Open the database. */
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status = internal_setent (keep_db);
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if (status != NSS_STATUS_SUCCESS)
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{
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*errnop = errno;
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H_ERRNO_SET (NETDB_INTERNAL);
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return status;
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}
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/* Succeed iff it matches a value that parses correctly. */
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err = (*db->get) (db, key, &value, 0);
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if (err < 0)
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{
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*errnop = errno;
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H_ERRNO_SET (NETDB_INTERNAL);
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status = NSS_STATUS_UNAVAIL;
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}
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else if (err != 0)
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{
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H_ERRNO_SET (HOST_NOT_FOUND);
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status = NSS_STATUS_NOTFOUND;
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}
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else if (buflen < value.size)
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{
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/* No room to copy the data to. */
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*errnop = ERANGE;
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H_ERRNO_SET (NETDB_INTERNAL);
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status = NSS_STATUS_TRYAGAIN;
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}
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else
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{
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/* Copy the result to a safe place. */
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p = (char *) memcpy (buffer, value.data, value.size);
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/* Skip leading blanks. */
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while (isspace (*p))
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++p;
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err = parse_line (p, result, buffer, buflen, errnop);
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if (err == 0)
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{
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/* If the key begins with '0' we are trying to get the next
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entry. We want to ignore unparsable lines in this case. */
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if (((char *) key->data)[0] == '0')
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{
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/* Super magical return value. We need to tell our caller
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that it should continue looping. This value cannot
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happen in other cases. */
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status = NSS_STATUS_RETURN;
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}
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else
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{
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H_ERRNO_SET (HOST_NOT_FOUND);
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status = NSS_STATUS_NOTFOUND;
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}
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}
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else if (err < 0)
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{
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H_ERRNO_SET (NETDB_INTERNAL);
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status = NSS_STATUS_TRYAGAIN;
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}
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else
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status = NSS_STATUS_SUCCESS;
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}
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if (! keep_db)
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internal_endent ();
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return status;
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}
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/* Macro for defining lookup functions for this DB-based database.
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NAME is the name of the lookup; e.g. `pwnam'.
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KEYPATTERN gives `printf' args to construct a key string;
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e.g. `(".%s", name)'.
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KEYSIZE gives the allocation size of a buffer to construct it in;
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e.g. `1 + strlen (name)'.
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PROTO describes the arguments for the lookup key;
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e.g. `const char *name'.
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BREAK_IF_MATCH is ignored, but used by ../nss_files/files-XXX.c. */
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#define DB_LOOKUP(name, keysize, keypattern, break_if_match, proto...) \
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enum nss_status \
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_nss_db_get##name##_r (proto, \
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struct STRUCTURE *result, \
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char *buffer, size_t buflen, int *errnop H_ERRNO_PROTO)\
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{ \
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DBT key; \
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enum nss_status status; \
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const size_t size = (keysize) + 1; \
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key.data = __alloca (size); \
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key.size = KEYPRINTF keypattern; \
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__libc_lock_lock (lock); \
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status = lookup (&key, result, buffer, buflen, errnop H_ERRNO_ARG); \
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__libc_lock_unlock (lock); \
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return status; \
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}
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#define KEYPRINTF(pattern, args...) snprintf (key.data, size, pattern ,##args)
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/* Return the next entry from the database file, doing locking. */
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enum nss_status
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CONCAT(_nss_db_get,ENTNAME_r) (struct STRUCTURE *result, char *buffer,
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size_t buflen, int *errnop H_ERRNO_PROTO)
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{
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/* Return next entry in host file. */
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enum nss_status status;
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char buf[20];
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DBT key;
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__libc_lock_lock (lock);
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/* Loop until we find a valid entry or hit EOF. See above for the
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special meaning of the status value. */
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do
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{
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key.size = snprintf (key.data = buf, sizeof buf, "0%u", entidx++);
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status = lookup (&key, result, buffer, buflen, errnop H_ERRNO_ARG);
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}
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while (status == NSS_STATUS_RETURN);
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__libc_lock_unlock (lock);
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return status;
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}
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