/* Common code for file-based databases in nss_files module.
Copyright (C) 1996-2013 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
<http://www.gnu.org/licenses/>. */
#include <nss.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include "compat.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 ALTFILES_DATADIR "/" DATABASE
#ifdef NEED_H_ERRNO
# include <netdb.h>
# 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
#ifndef EXTRA_ARGS
# define EXTRA_ARGS
# define EXTRA_ARGS_DECL
# define EXTRA_ARGS_VALUE
#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 fpos_t position;
static enum { nouse, getent, getby } last_use;
static int keep_stream;
/* Open database file if not already opened. */
static enum nss_status
internal_setent (int stayopen)
{
enum nss_status status = NSS_STATUS_SUCCESS;
if (stream == NULL)
{
stream = fopen (DATAFILE, "rce");
if (stream == NULL)
status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
else
{
#if !defined O_CLOEXEC || !defined __ASSUME_O_CLOEXEC
# ifdef O_CLOEXEC
if (__have_o_cloexec <= 0)
# endif
{
/* We have to make sure the file is `closed on exec'. */
int result;
int flags;
result = flags = fcntl (fileno (stream), F_GETFD, 0);
if (result >= 0)
{
# ifdef O_CLOEXEC
if (__have_o_cloexec == 0)
__have_o_cloexec = (flags & FD_CLOEXEC) == 0 ? -1 : 1;
if (__have_o_cloexec < 0)
# endif
{
flags |= FD_CLOEXEC;
result = fcntl (fileno (stream), F_SETFD, flags);
}
}
if (result < 0)
{
/* Something went wrong. Close the stream and return a
failure. */
fclose (stream);
stream = NULL;
status = NSS_STATUS_UNAVAIL;
}
}
#endif
}
}
else
rewind (stream);
/* Remember STAYOPEN flag. */
if (stream != NULL)
keep_stream |= stayopen;
return status;
}
/* Thread-safe, exported version of that. */
enum nss_status
CONCAT(CONCAT(CONCAT(_nss_, ALTFILES_MODULE_NAME), _set), ENTNAME) (int stayopen)
{
enum nss_status status;
__libc_lock_lock (lock);
status = internal_setent (stayopen);
if (status == NSS_STATUS_SUCCESS && fgetpos (stream, &position) < 0)
{
fclose (stream);
stream = NULL;
status = NSS_STATUS_UNAVAIL;
}
last_use = getent;
__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. */
enum nss_status
CONCAT(CONCAT(CONCAT(_nss_, ALTFILES_MODULE_NAME), _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, size_t buflen, int *errnop H_ERRNO_PROTO
EXTRA_ARGS_DECL)
{
char *p;
struct parser_data *data = (void *) buffer;
int linebuflen = buffer + buflen - data->linebuffer;
int parse_result;
if (buflen < sizeof *data + 2)
{
*errnop = ERANGE;
H_ERRNO_SET (NETDB_INTERNAL);
return NSS_STATUS_TRYAGAIN;
}
do
{
/* Terminate the line so that we can test for overflow. */
((unsigned char *) data->linebuffer)[linebuflen - 1] = '\xff';
p = fgets_unlocked (data->linebuffer, linebuflen, stream);
if (p == NULL)
{
/* End of file or read error. */
H_ERRNO_SET (HOST_NOT_FOUND);
return NSS_STATUS_NOTFOUND;
}
else if (((unsigned char *) data->linebuffer)[linebuflen - 1] != 0xff)
{
/* The line is too long. Give the user the opportunity to
enlarge the buffer. */
*errnop = ERANGE;
H_ERRNO_SET (NETDB_INTERNAL);
return NSS_STATUS_TRYAGAIN;
}
/* 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_result = parse_line (p, result, data, buflen, errnop
EXTRA_ARGS)));
if (__builtin_expect (parse_result == -1, 0))
{
H_ERRNO_SET (NETDB_INTERNAL);
return NSS_STATUS_TRYAGAIN;
}
/* 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. */
enum nss_status
CONCAT(CONCAT(CONCAT(_nss_, ALTFILES_MODULE_NAME), _get), ENTNAME_r) (struct STRUCTURE *result, char *buffer,
size_t buflen, int *errnop H_ERRNO_PROTO)
{
/* Return next entry in host file. */
enum nss_status status = NSS_STATUS_SUCCESS;
__libc_lock_lock (lock);
/* Be prepared that the set*ent function was not called before. */
if (stream == NULL)
{
int save_errno = errno;
status = internal_setent (0);
__set_errno (save_errno);
if (status == NSS_STATUS_SUCCESS && fgetpos (stream, &position) < 0)
{
fclose (stream);
stream = NULL;
status = NSS_STATUS_UNAVAIL;
}
}
if (status == NSS_STATUS_SUCCESS)
{
/* If the last use was not by the getent function we need the
position the stream. */
if (last_use != getent)
{
if (fsetpos (stream, &position) < 0)
status = NSS_STATUS_UNAVAIL;
else
last_use = getent;
}
if (status == NSS_STATUS_SUCCESS)
{
status = internal_getent (result, buffer, buflen, errnop
H_ERRNO_ARG EXTRA_ARGS_VALUE);
/* Remember this position if we were successful. If the
operation failed we give the user a chance to repeat the
operation (perhaps the buffer was too small). */
if (status == NSS_STATUS_SUCCESS)
fgetpos (stream, &position);
else
/* We must make sure we reposition the stream the next call. */
last_use = nouse;
}
}
__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'.
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 \
CONCAT(CONCAT(_nss_, ALTFILES_MODULE_NAME), _get ## name ## _r) (proto, \
struct STRUCTURE *result, char *buffer, \
size_t buflen, int *errnop H_ERRNO_PROTO) \
{ \
enum nss_status status; \
\
__libc_lock_lock (lock); \
\
/* Reset file pointer to beginning or open file. */ \
status = internal_setent (keep_stream); \
\
if (status == NSS_STATUS_SUCCESS) \
{ \
/* Tell getent function that we have repositioned the file pointer. */ \
last_use = getby; \
\
while ((status = internal_getent (result, buffer, buflen, errnop \
H_ERRNO_ARG EXTRA_ARGS_VALUE)) \
== NSS_STATUS_SUCCESS) \
{ break_if_match } \
\
if (! keep_stream) \
internal_endent (); \
} \
\
__libc_lock_unlock (lock); \
\
return status; \
}