[thirdparty/glibc.git] / nss / nss_files / files-XXX.c

/* Common code for file-based databases in nss_files module.
   Copyright (C) 1996, 1997, 1998 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., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <stdio.h>
#include <ctype.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <bits/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.

   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_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)
\f
/* Maintenance of the shared stream open on the database file.  */

static FILE *stream;
static fpos_t position;
static enum { none, 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, "r");

      if (stream == NULL)
	status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
      else
	{
	  /* We have to make sure the file is  `closed on exec'.  */
	  int result, flags;

	  result = flags = fcntl (fileno (stream), F_GETFD, 0);
	  if (result >= 0)
	    {
	      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;
	    }
	}
    }
  else
    rewind (stream);

  /* Remember STAYOPEN flag.  */
  if (stream != NULL)
    keep_stream |= stayopen;

  return status;
}


/* Thread-safe, exported version of that.  */
enum nss_status
CONCAT(_nss_files_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(_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;
}
\f
/* Parsing the database file into `struct STRUCTURE' data structures.  */

static enum nss_status
internal_getent (struct STRUCTURE *result,
		 char *buffer, int buflen, int *errnop H_ERRNO_PROTO)
{
  char *p;
  struct parser_data *data = (void *) buffer;
  int linebuflen = buffer + buflen - data->linebuffer;
  int parse_result;

  if (buflen < (int) sizeof *data + 1)
    {
      *errnop = ERANGE;
      H_ERRNO_SET (NETDB_INTERNAL);
      return NSS_STATUS_TRYAGAIN;
    }

  do
    {
      /* Terminate the line so that we can test for overflow.  */
      data->linebuffer[linebuflen - 1] = '\xff';

      p = fgets (data->linebuffer, linebuflen, stream);
      if (p == NULL)
	{
	  /* End of file or read error.  */
	  *errnop = errno;
	  H_ERRNO_SET (HOST_NOT_FOUND);
	  return NSS_STATUS_NOTFOUND;
	}
      else if (data->linebuffer[linebuflen - 1] != '\xff')
	{
	  /* 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)));

  /* Filled in RESULT with the next entry from the database file.  */
  return parse_result == -1 ? NSS_STATUS_TRYAGAIN : NSS_STATUS_SUCCESS;
}


/* 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.  */
  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)
    status = internal_setent (0);

  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);

	  /* 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 = none;
	}
    }

  __libc_lock_unlock (lock);

  return status;
}
\f
/* 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,	      \
			  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))			      \
	     == NSS_STATUS_SUCCESS)					      \
	{ break_if_match }						      \
									      \
      if (! keep_stream)						      \
	internal_endent ();						      \
    }									      \
									      \
  __libc_lock_unlock (lock);						      \
									      \
  return status;							      \
}
Commit	Line	Data
5f0e6fc7	1	/* Common code for file-based databases in nss_files module.
af69217f	2	Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
2303f5fd	3	This file is part of the GNU C Library.
5f0e6fc7	4
2303f5fd UD	5	The GNU C Library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Library General Public License as
	7	published by the Free Software Foundation; either version 2 of the
	8	License, or (at your option) any later version.
5f0e6fc7	9
2303f5fd UD	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Library General Public License for more details.
5f0e6fc7	14
2303f5fd UD	15	You should have received a copy of the GNU Library General Public
	16	License along with the GNU C Library; see the file COPYING.LIB. If not,
	17	write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	18	Boston, MA 02111-1307, USA. */
5f0e6fc7 RM	19
	20	#include <stdio.h>
	21	#include <ctype.h>
	22	#include <assert.h>
26761c28	23	#include <errno.h>
3996f34b	24	#include <fcntl.h>
5107cf1d	25	#include <bits/libc-lock.h>
5f0e6fc7 RM	26	#include "nsswitch.h"
	27
	28	/* These symbols are defined by the including source file:
	29
	30	ENTNAME -- database name of the structure and functions (hostent, pwent).
	31	STRUCTURE -- struct name, define only if not ENTNAME (passwd, group).
96bda0ea	32	DATABASE -- string of the database file's name ("hosts", "passwd").
5f0e6fc7 RM	33
5f0e6fc7 RM	34	NEED_H_ERRNO - defined iff an arg `int *herrnop' is used.
adc6ff7f RM	35
adc6ff7f RM	36	Also see files-parse.c.
5f0e6fc7 RM	37	*/
5f0e6fc7 RM	38
96bda0ea RM	39	#define ENTNAME_r CONCAT(ENTNAME,_r)
	40
	41	#define DATAFILE "/etc/" DATABASE
5f0e6fc7 RM	42
5f0e6fc7 RM	43	#ifdef NEED_H_ERRNO
47707456	44	# include <netdb.h>
26761c28 UD	45	# define H_ERRNO_PROTO , int *herrnop
	46	# define H_ERRNO_ARG , herrnop
	47	# define H_ERRNO_SET(val) (*herrnop = (val))
5f0e6fc7	48	#else
26761c28 UD	49	# define H_ERRNO_PROTO
	50	# define H_ERRNO_ARG
	51	# define H_ERRNO_SET(val) ((void) 0)
5f0e6fc7 RM	52	#endif
	53
	54	/* Locks the static variables in this file. */
1e16111c	55	__libc_lock_define_initialized (static, lock)
5f0e6fc7 RM	56	\f
	57	/* Maintenance of the shared stream open on the database file. */
	58
	59	static FILE *stream;
2303f5fd UD	60	static fpos_t position;
2303f5fd UD	61	static enum { none, getent, getby } last_use;
5f0e6fc7 RM	62	static int keep_stream;
	63
	64	/* Open database file if not already opened. */
26761c28	65	static enum nss_status
5f0e6fc7 RM	66	internal_setent (int stayopen)
5f0e6fc7 RM	67	{
26761c28	68	enum nss_status status = NSS_STATUS_SUCCESS;
5f0e6fc7 RM	69
	70	if (stream == NULL)
	71	{
	72	stream = fopen (DATAFILE, "r");
	73
	74	if (stream == NULL)
0413b54c	75	status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
3996f34b UD	76	else
	77	{
	78	/* We have to make sure the file is `closed on exec'. */
	79	int result, flags;
	80
	81	result = flags = fcntl (fileno (stream), F_GETFD, 0);
	82	if (result >= 0)
	83	{
	84	flags \|= FD_CLOEXEC;
	85	result = fcntl (fileno (stream), F_SETFD, flags);
	86	}
	87	if (result < 0)
	88	{
	89	/* Something went wrong. Close the stream and return a
	90	failure. */
	91	fclose (stream);
	92	stream = NULL;
	93	status = NSS_STATUS_UNAVAIL;
	94	}
	95	}
5f0e6fc7 RM	96	}
	97	else
	98	rewind (stream);
	99
	100	/* Remember STAYOPEN flag. */
	101	if (stream != NULL)
	102	keep_stream \|= stayopen;
	103
	104	return status;
	105	}
	106
	107
	108	/* Thread-safe, exported version of that. */
26761c28	109	enum nss_status
5f0e6fc7 RM	110	CONCAT(_nss_files_set,ENTNAME) (int stayopen)
5f0e6fc7 RM	111	{
26761c28	112	enum nss_status status;
5f0e6fc7 RM	113
	114	__libc_lock_lock (lock);
	115
	116	status = internal_setent (stayopen);
	117
2303f5fd UD	118	if (status == NSS_STATUS_SUCCESS && fgetpos (stream, &position) < 0)
	119	{
	120	fclose (stream);
	121	stream = NULL;
	122	status = NSS_STATUS_UNAVAIL;
	123	}
	124
	125	last_use = getent;
	126
5f0e6fc7 RM	127	__libc_lock_unlock (lock);
	128
	129	return status;
	130	}
	131
	132
	133	/* Close the database file. */
	134	static void
	135	internal_endent (void)
	136	{
	137	if (stream != NULL)
	138	{
	139	fclose (stream);
	140	stream = NULL;
	141	}
5f0e6fc7 RM	142	}
	143
	144
	145	/* Thread-safe, exported version of that. */
26761c28	146	enum nss_status
5f0e6fc7 RM	147	CONCAT(_nss_files_end,ENTNAME) (void)
	148	{
	149	__libc_lock_lock (lock);
	150
	151	internal_endent ();
	152
6dbe2837 RM	153	/* Reset STAYOPEN flag. */
	154	keep_stream = 0;
	155
5f0e6fc7 RM	156	__libc_lock_unlock (lock);
	157
	158	return NSS_STATUS_SUCCESS;
	159	}
	160	\f
	161	/* Parsing the database file into `struct STRUCTURE' data structures. */
	162
	163	static enum nss_status
	164	internal_getent (struct STRUCTURE *result,
d71b808a	165	char buffer, int buflen, int errnop H_ERRNO_PROTO)
5f0e6fc7 RM	166	{
	167	char *p;
	168	struct parser_data data = (void ) buffer;
	169	int linebuflen = buffer + buflen - data->linebuffer;
22d57dd3	170	int parse_result;
5f0e6fc7	171
6dbe2837	172	if (buflen < (int) sizeof *data + 1)
5f0e6fc7	173	{
d71b808a	174	*errnop = ERANGE;
47707456	175	H_ERRNO_SET (NETDB_INTERNAL);
ffee1316	176	return NSS_STATUS_TRYAGAIN;
5f0e6fc7 RM	177	}
	178
	179	do
	180	{
26761c28	181	/* Terminate the line so that we can test for overflow. */
af69217f	182	data->linebuffer[linebuflen - 1] = '\xff';
26761c28	183
5f0e6fc7 RM	184	p = fgets (data->linebuffer, linebuflen, stream);
	185	if (p == NULL)
	186	{
	187	/* End of file or read error. */
d71b808a	188	*errnop = errno;
5f0e6fc7 RM	189	H_ERRNO_SET (HOST_NOT_FOUND);
	190	return NSS_STATUS_NOTFOUND;
	191	}
af69217f	192	else if (data->linebuffer[linebuflen - 1] != '\xff')
26761c28 UD	193	{
	194	/* The line is too long. Give the user the opportunity to
	195	enlarge the buffer. */
d71b808a	196	*errnop = ERANGE;
26761c28 UD	197	H_ERRNO_SET (NETDB_INTERNAL);
	198	return NSS_STATUS_TRYAGAIN;
	199	}
6dbe2837	200
5f0e6fc7 RM	201	/* Skip leading blanks. */
	202	while (isspace (*p))
	203	++p;
26761c28 UD	204	}
	205	while (p == '\0' \|\| p == '#' /* Ignore empty and comment lines. */
	206	/* Parse the line. If it is invalid, loop to get the next
	207	line of the file to parse. */
d71b808a	208	\|\| ! (parse_result = parse_line (p, result, data, buflen, errnop)));
5f0e6fc7 RM	209
5f0e6fc7 RM	210	/* Filled in RESULT with the next entry from the database file. */
22d57dd3	211	return parse_result == -1 ? NSS_STATUS_TRYAGAIN : NSS_STATUS_SUCCESS;
5f0e6fc7 RM	212	}
	213
	214
	215	/* Return the next entry from the database file, doing locking. */
26761c28	216	enum nss_status
d71b808a UD	217	CONCAT(_nss_files_get,ENTNAME_r) (struct STRUCTURE result, char buffer,
d71b808a UD	218	size_t buflen, int *errnop H_ERRNO_PROTO)
5f0e6fc7 RM	219	{
5f0e6fc7 RM	220	/* Return next entry in host file. */
26761c28	221	enum nss_status status = NSS_STATUS_SUCCESS;
5f0e6fc7 RM	222
	223	__libc_lock_lock (lock);
	224
26761c28 UD	225	/* Be prepared that the setent function was not called before. /
	226	if (stream == NULL)
	227	status = internal_setent (0);
2303f5fd	228
54d79e99	229	if (status == NSS_STATUS_SUCCESS)
2303f5fd	230	{
26761c28 UD	231	/* If the last use was not by the getent function we need the
	232	position the stream. */
	233	if (last_use != getent)
	234	if (fsetpos (stream, &position) < 0)
	235	status = NSS_STATUS_UNAVAIL;
	236	else
	237	last_use = getent;
	238
	239	if (status == NSS_STATUS_SUCCESS)
	240	{
d71b808a UD	241	status = internal_getent (result, buffer, buflen, errnop
d71b808a UD	242	H_ERRNO_ARG);
26761c28 UD	243
	244	/* Remember this position if we were successful. If the
	245	operation failed we give the user a chance to repeat the
	246	operation (perhaps the buffer was too small). */
	247	if (status == NSS_STATUS_SUCCESS)
	248	fgetpos (stream, &position);
	249	else
	250	/* We must make sure we reposition the stream the next call. */
	251	last_use = none;
	252	}
2303f5fd	253	}
5f0e6fc7 RM	254
	255	__libc_lock_unlock (lock);
	256
	257	return status;
	258	}
	259	\f
	260	/* Macro for defining lookup functions for this file-based database.
	261
	262	NAME is the name of the lookup; e.g. `hostbyname'.
	263
96bda0ea RM	264	KEYSIZE and KEYPATTERN are ignored here but used by ../nss_db/db-XXX.c.
96bda0ea RM	265
5f0e6fc7 RM	266	PROTO describes the arguments for the lookup key;
	267	e.g. `const char *hostname'.
	268
	269	BREAK_IF_MATCH is a block of code which compares `struct STRUCTURE *result'
	270	to the lookup key arguments and does `break;' if they match. */
	271
96bda0ea	272	#define DB_LOOKUP(name, keysize, keypattern, break_if_match, proto...) \
5f0e6fc7 RM	273	enum nss_status \
5f0e6fc7 RM	274	_nss_files_get##name##_r (proto, \
d71b808a UD	275	struct STRUCTURE result, char buffer, \
d71b808a UD	276	size_t buflen, int *errnop H_ERRNO_PROTO) \
5f0e6fc7 RM	277	{ \
	278	enum nss_status status; \
	279	\
	280	__libc_lock_lock (lock); \
	281	\
	282	/* Reset file pointer to beginning or open file. */ \
26761c28	283	status = internal_setent (keep_stream); \
5f0e6fc7	284	\
26761c28 UD	285	if (status == NSS_STATUS_SUCCESS) \
	286	{ \
	287	/* Tell getent function that we have repositioned the file pointer. */ \
	288	last_use = getby; \
2303f5fd	289	\
d71b808a UD	290	while ((status = internal_getent (result, buffer, buflen, errnop \
d71b808a UD	291	H_ERRNO_ARG)) \
26761c28 UD	292	== NSS_STATUS_SUCCESS) \
26761c28 UD	293	{ break_if_match } \
5f0e6fc7	294	\
26761c28 UD	295	if (! keep_stream) \
	296	internal_endent (); \
	297	} \
5f0e6fc7 RM	298	\
	299	__libc_lock_unlock (lock); \
	300	\
	301	return status; \
	302	}