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/* Common code for file-based databases in nss_files module.
Copyright (C) 1996-2025 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <libc-lock.h>
#include "nsswitch.h"
#include <nss_files.h>
#include <kernel-features.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.
Also see files-parse.c.
*/
#define ENTNAME_r CONCAT(ENTNAME,_r)
#define DATAFILE "/etc/" DATABASE
#ifdef NEED_H_ERRNO
# include <netdb.h>
# define H_ERRNO_PROTO , int *herrnop
# define H_ERRNO_ARG , herrnop
# define H_ERRNO_ARG_OR_NULL herrnop
# define H_ERRNO_SET(val) (*herrnop = (val))
#else
# define H_ERRNO_PROTO
# define H_ERRNO_ARG
# define H_ERRNO_ARG_OR_NULL NULL
# define H_ERRNO_SET(val) ((void) 0)
#endif
#ifndef EXTRA_ARGS
# define EXTRA_ARGS
# define EXTRA_ARGS_DECL
# define EXTRA_ARGS_VALUE
#endif
/* Maintenance of the stream open on the database file. For getXXent
operations the stream needs to be held open across calls, the other
getXXbyYY operations all use their own stream. */
/* Open database file if not already opened. */
static enum nss_status
internal_setent (FILE **stream)
{
enum nss_status status = NSS_STATUS_SUCCESS;
if (*stream == NULL)
{
*stream = __nss_files_fopen (DATAFILE);
if (*stream == NULL)
status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
}
else
rewind (*stream);
return status;
}
/* Thread-safe, exported version of that. */
enum nss_status
CONCAT(_nss_files_set,ENTNAME) (int stayopen)
{
return __nss_files_data_setent (CONCAT (nss_file_, ENTNAME), DATAFILE);
}
libc_hidden_def (CONCAT (_nss_files_set,ENTNAME))
enum nss_status
CONCAT(_nss_files_end,ENTNAME) (void)
{
return __nss_files_data_endent (CONCAT (nss_file_, ENTNAME));
}
libc_hidden_def (CONCAT (_nss_files_end,ENTNAME))
/* Parsing the database file into `struct STRUCTURE' data structures. */
static enum nss_status
internal_getent (FILE *stream, struct STRUCTURE *result,
char *buffer, size_t buflen, int *errnop H_ERRNO_PROTO
EXTRA_ARGS_DECL)
{
struct parser_data *data = (void *) buffer;
size_t linebuflen = buffer + buflen - data->linebuffer;
int saved_errno = errno; /* Do not clobber errno on success. */
if (buflen < sizeof *data + 2)
{
*errnop = ERANGE;
H_ERRNO_SET (NETDB_INTERNAL);
return NSS_STATUS_TRYAGAIN;
}
while (true)
{
off64_t original_offset;
int ret = __nss_readline (stream, data->linebuffer, linebuflen,
&original_offset);
if (ret == ENOENT)
{
/* End of file. */
H_ERRNO_SET (HOST_NOT_FOUND);
__set_errno (saved_errno);
return NSS_STATUS_NOTFOUND;
}
else if (ret == 0)
{
ret = __nss_parse_line_result (stream, original_offset,
parse_line (data->linebuffer,
result, data, buflen,
errnop EXTRA_ARGS));
if (ret == 0)
{
/* Line has been parsed successfully. */
__set_errno (saved_errno);
return NSS_STATUS_SUCCESS;
}
else if (ret == EINVAL)
/* If it is invalid, loop to get the next line of the file
to parse. */
continue;
}
*errnop = ret;
H_ERRNO_SET (NETDB_INTERNAL);
if (ret == ERANGE)
/* Request larger buffer. */
return NSS_STATUS_TRYAGAIN;
else
/* Other read failure. */
return NSS_STATUS_UNAVAIL;
}
}
/* Return the next entry from the database file, doing locking. */
enum nss_status
CONCAT(_nss_files_get,ENTNAME_r) (struct STRUCTURE *result, char *buffer,
size_t buflen, int *errnop H_ERRNO_PROTO)
{
/* Return next entry in host file. */
struct nss_files_per_file_data *data;
enum nss_status status = __nss_files_data_open (&data,
CONCAT (nss_file_, ENTNAME),
DATAFILE,
errnop, H_ERRNO_ARG_OR_NULL);
if (status != NSS_STATUS_SUCCESS)
return status;
status = internal_getent (data->stream, result, buffer, buflen, errnop
H_ERRNO_ARG EXTRA_ARGS_VALUE);
__nss_files_data_put (data);
return status;
}
libc_hidden_def (CONCAT (_nss_files_get,ENTNAME_r))
/* Macro for defining lookup functions for this file-based database.
NAME is the name of the lookup; e.g. `hostbyname'.
DB_CHAR, KEYPATTERN, KEYSIZE are ignored here but used by db-XXX.c
e.g. `1 + sizeof (id) * 4'.
PROTO is the potentially empty list of other parameters.
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, db_char, keysize, keypattern, break_if_match, proto...)\
enum nss_status \
_nss_files_get##name##_r (proto, \
struct STRUCTURE *result, char *buffer, \
size_t buflen, int *errnop H_ERRNO_PROTO) \
{ \
enum nss_status status; \
FILE *stream = NULL; \
\
/* Open file. */ \
status = internal_setent (&stream); \
\
if (status == NSS_STATUS_SUCCESS) \
{ \
while ((status = internal_getent (stream, result, buffer, buflen, errnop \
H_ERRNO_ARG EXTRA_ARGS_VALUE)) \
== NSS_STATUS_SUCCESS) \
{ break_if_match } \
\
fclose (stream); \
} \
\
return status; \
} \
libc_hidden_def (_nss_files_get##name##_r)
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