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/* Common code for file-based databases in nss_files 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 <stdio.h>
#include <ctype.h>
#include <assert.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 -- string of the database file's name ("hosts", "passwd").
NEED_H_ERRNO - defined iff an arg `int *herrnop' is used.
MIDLINE_COMMENTS - defined iff # before \n terminates a database line.
*/
#define ENTNAME_r CONCAT(ENTNAME,_r)
#define DATAFILE "/etc/" DATABASE
#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 stream open on the database file. */
static FILE *stream;
static int keep_stream;
/* Open database file if not already opened. */
static int
internal_setent (int stayopen)
{
int status = NSS_STATUS_SUCCESS;
if (stream == NULL)
{
stream = fopen (DATAFILE, "r");
if (stream == NULL)
status = NSS_STATUS_UNAVAIL;
}
else
rewind (stream);
/* Remember STAYOPEN flag. */
if (stream != NULL)
keep_stream |= stayopen;
return status;
}
/* Thread-safe, exported version of that. */
int
CONCAT(_nss_files_set,ENTNAME) (int stayopen)
{
int status;
__libc_lock_lock (lock);
status = internal_setent (stayopen);
__libc_lock_unlock (lock);
return status;
}
/* Close the database file. */
static void
internal_endent (void)
{
if (stream != NULL)
{
fclose (stream);
stream = NULL;
}
}
/* Thread-safe, exported version of that. */
int
CONCAT(_nss_files_end,ENTNAME) (void)
{
__libc_lock_lock (lock);
internal_endent ();
/* Reset STAYOPEN flag. */
keep_stream = 0;
__libc_lock_unlock (lock);
return NSS_STATUS_SUCCESS;
}
/* Parsing the database file into `struct STRUCTURE' data structures. */
static enum nss_status
internal_getent (struct STRUCTURE *result,
char *buffer, int buflen H_ERRNO_PROTO)
{
char *p;
struct parser_data *data = (void *) buffer;
int linebuflen = buffer + buflen - data->linebuffer;
/* Be prepared that the set*ent function was not called before. */
if (stream == NULL)
{
enum nss_status status;
status = internal_setent (0);
if (status != NSS_STATUS_SUCCESS)
return status;
}
if (buflen < (int) sizeof *data + 1)
{
errno = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
do
{
p = fgets (data->linebuffer, linebuflen, stream);
if (p == NULL)
{
/* End of file or read error. */
H_ERRNO_SET (HOST_NOT_FOUND);
return NSS_STATUS_NOTFOUND;
}
/* Terminate the line for any case. */
data->linebuffer[linebuflen - 1] = '\0';
/* Skip leading blanks. */
while (isspace (*p))
++p;
} while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
/* Parse the line. If it is invalid, loop to
get the next line of the file to parse. */
! parse_line (p, result, data, buflen));
/* Filled in RESULT with the next entry from the database file. */
return NSS_STATUS_SUCCESS;
}
/* Return the next entry from the database file, doing locking. */
int
CONCAT(_nss_files_get,ENTNAME_r) (struct STRUCTURE *result,
char *buffer, int buflen H_ERRNO_PROTO)
{
/* Return next entry in host file. */
int status;
__libc_lock_lock (lock);
status = internal_getent (result, buffer, buflen H_ERRNO_ARG);
__libc_lock_unlock (lock);
return status;
}
/* Macro for defining lookup functions for this file-based database.
NAME is the name of the lookup; e.g. `hostbyname'.
KEYSIZE and KEYPATTERN are ignored here but used by ../nss_db/db-XXX.c.
PROTO describes the arguments for the lookup key;
e.g. `const char *hostname'.
BREAK_IF_MATCH is a block of code which compares `struct STRUCTURE *result'
to the lookup key arguments and does `break;' if they match. */
#define DB_LOOKUP(name, keysize, keypattern, break_if_match, proto...) \
enum nss_status \
_nss_files_get##name##_r (proto, \
struct STRUCTURE *result, \
char *buffer, int buflen H_ERRNO_PROTO) \
{ \
enum nss_status status; \
\
__libc_lock_lock (lock); \
\
/* Reset file pointer to beginning or open file. */ \
internal_setent (keep_stream); \
\
while ((status = internal_getent (result, buffer, buflen H_ERRNO_ARG)) \
== NSS_STATUS_SUCCESS) \
{ break_if_match } \
\
if (! keep_stream) \
internal_endent (); \
\
__libc_lock_unlock (lock); \
\
return status; \
}
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