1 /* Common code for file-based databases in nss_files module.
2 Copyright (C) 1996-2014 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
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 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
23 #include <bits/libc-lock.h>
26 #include <kernel-features.h>
28 /* These symbols are defined by the including source file:
30 ENTNAME -- database name of the structure and functions (hostent, pwent).
31 STRUCTURE -- struct name, define only if not ENTNAME (passwd, group).
32 DATABASE -- string of the database file's name ("hosts", "passwd").
34 NEED_H_ERRNO - defined iff an arg `int *herrnop' is used.
36 Also see files-parse.c.
39 #define ENTNAME_r CONCAT(ENTNAME,_r)
41 #define DATAFILE "/etc/" DATABASE
45 # define H_ERRNO_PROTO , int *herrnop
46 # define H_ERRNO_ARG , herrnop
47 # define H_ERRNO_SET(val) (*herrnop = (val))
49 # define H_ERRNO_PROTO
51 # define H_ERRNO_SET(val) ((void) 0)
56 # define EXTRA_ARGS_DECL
57 # define EXTRA_ARGS_VALUE
60 /* Locks the static variables in this file. */
61 __libc_lock_define_initialized (static, lock
)
63 /* Maintenance of the shared stream open on the database file. */
66 static fpos_t position
;
67 static enum { nouse
, getent
, getby
} last_use
;
68 static int keep_stream
;
70 /* Open database file if not already opened. */
71 static enum nss_status
72 internal_setent (int stayopen
)
74 enum nss_status status
= NSS_STATUS_SUCCESS
;
78 stream
= fopen (DATAFILE
, "rce");
81 status
= errno
== EAGAIN
? NSS_STATUS_TRYAGAIN
: NSS_STATUS_UNAVAIL
;
84 #if !defined O_CLOEXEC || !defined __ASSUME_O_CLOEXEC
86 if (__have_o_cloexec
<= 0)
89 /* We have to make sure the file is `closed on exec'. */
93 result
= flags
= fcntl (fileno (stream
), F_GETFD
, 0);
97 if (__have_o_cloexec
== 0)
98 __have_o_cloexec
= (flags
& FD_CLOEXEC
) == 0 ? -1 : 1;
99 if (__have_o_cloexec
< 0)
103 result
= fcntl (fileno (stream
), F_SETFD
, flags
);
108 /* Something went wrong. Close the stream and return a
112 status
= NSS_STATUS_UNAVAIL
;
121 /* Remember STAYOPEN flag. */
123 keep_stream
|= stayopen
;
129 /* Thread-safe, exported version of that. */
131 CONCAT(_nss_files_set
,ENTNAME
) (int stayopen
)
133 enum nss_status status
;
135 __libc_lock_lock (lock
);
137 status
= internal_setent (stayopen
);
139 if (status
== NSS_STATUS_SUCCESS
&& fgetpos (stream
, &position
) < 0)
143 status
= NSS_STATUS_UNAVAIL
;
148 __libc_lock_unlock (lock
);
154 /* Close the database file. */
156 internal_endent (void)
166 /* Thread-safe, exported version of that. */
168 CONCAT(_nss_files_end
,ENTNAME
) (void)
170 __libc_lock_lock (lock
);
174 /* Reset STAYOPEN flag. */
177 __libc_lock_unlock (lock
);
179 return NSS_STATUS_SUCCESS
;
190 /* Hack around the fact that fgets only accepts int sizes. */
191 static get_contents_ret
192 get_contents (char *linebuf
, size_t len
, FILE *stream
)
194 size_t remaining_len
= len
;
195 char *curbuf
= linebuf
;
199 int curlen
= ((remaining_len
> (size_t) INT_MAX
) ? INT_MAX
201 char *p
= fgets_unlocked (curbuf
, curlen
, stream
);
203 ((unsigned char *) curbuf
)[curlen
- 1] = 0xff;
205 /* EOF or read error. */
209 /* Done reading in the line. */
210 if (((unsigned char *) curbuf
)[curlen
- 1] == 0xff)
213 /* Drop the terminating '\0'. */
214 remaining_len
-= curlen
- 1;
215 curbuf
+= curlen
- 1;
217 /* fgets copies one less than the input length. Our last iteration is of
218 REMAINING_LEN and once that is done, REMAINING_LEN is decremented by
219 REMAINING_LEN - 1, leaving the result as 1. */
220 while (remaining_len
> 1);
222 /* This means that the current buffer was not large enough. */
226 /* Parsing the database file into `struct STRUCTURE' data structures. */
227 static enum nss_status
228 internal_getent (struct STRUCTURE
*result
,
229 char *buffer
, size_t buflen
, int *errnop H_ERRNO_PROTO
233 struct parser_data
*data
= (void *) buffer
;
234 size_t linebuflen
= buffer
+ buflen
- data
->linebuffer
;
237 if (buflen
< sizeof *data
+ 2)
240 H_ERRNO_SET (NETDB_INTERNAL
);
241 return NSS_STATUS_TRYAGAIN
;
246 get_contents_ret r
= get_contents (data
->linebuffer
, linebuflen
, stream
);
250 /* End of file or read error. */
251 H_ERRNO_SET (HOST_NOT_FOUND
);
252 return NSS_STATUS_NOTFOUND
;
255 if (r
== gcr_overflow
)
257 /* The line is too long. Give the user the opportunity to
258 enlarge the buffer. */
260 H_ERRNO_SET (NETDB_INTERNAL
);
261 return NSS_STATUS_TRYAGAIN
;
264 /* Everything OK. Now skip leading blanks. */
265 p
= data
->linebuffer
;
269 while (*p
== '\0' || *p
== '#' /* Ignore empty and comment lines. */
270 /* Parse the line. If it is invalid, loop to get the next
271 line of the file to parse. */
272 || ! (parse_result
= parse_line (p
, result
, data
, buflen
, errnop
275 if (__builtin_expect (parse_result
== -1, 0))
277 H_ERRNO_SET (NETDB_INTERNAL
);
278 return NSS_STATUS_TRYAGAIN
;
281 /* Filled in RESULT with the next entry from the database file. */
282 return NSS_STATUS_SUCCESS
;
286 /* Return the next entry from the database file, doing locking. */
288 CONCAT(_nss_files_get
,ENTNAME_r
) (struct STRUCTURE
*result
, char *buffer
,
289 size_t buflen
, int *errnop H_ERRNO_PROTO
)
291 /* Return next entry in host file. */
292 enum nss_status status
= NSS_STATUS_SUCCESS
;
294 __libc_lock_lock (lock
);
296 /* Be prepared that the set*ent function was not called before. */
299 int save_errno
= errno
;
301 status
= internal_setent (0);
303 __set_errno (save_errno
);
305 if (status
== NSS_STATUS_SUCCESS
&& fgetpos (stream
, &position
) < 0)
309 status
= NSS_STATUS_UNAVAIL
;
313 if (status
== NSS_STATUS_SUCCESS
)
315 /* If the last use was not by the getent function we need the
316 position the stream. */
317 if (last_use
!= getent
)
319 if (fsetpos (stream
, &position
) < 0)
320 status
= NSS_STATUS_UNAVAIL
;
325 if (status
== NSS_STATUS_SUCCESS
)
327 status
= internal_getent (result
, buffer
, buflen
, errnop
328 H_ERRNO_ARG EXTRA_ARGS_VALUE
);
330 /* Remember this position if we were successful. If the
331 operation failed we give the user a chance to repeat the
332 operation (perhaps the buffer was too small). */
333 if (status
== NSS_STATUS_SUCCESS
)
334 fgetpos (stream
, &position
);
336 /* We must make sure we reposition the stream the next call. */
341 __libc_lock_unlock (lock
);
346 /* Macro for defining lookup functions for this file-based database.
348 NAME is the name of the lookup; e.g. `hostbyname'.
350 DB_CHAR, KEYPATTERN, KEYSIZE are ignored here but used by db-XXX.c
351 e.g. `1 + sizeof (id) * 4'.
353 PROTO is the potentially empty list of other parameters.
355 BREAK_IF_MATCH is a block of code which compares `struct STRUCTURE *result'
356 to the lookup key arguments and does `break;' if they match. */
358 #define DB_LOOKUP(name, db_char, keysize, keypattern, break_if_match, proto...)\
360 _nss_files_get##name##_r (proto, \
361 struct STRUCTURE *result, char *buffer, \
362 size_t buflen, int *errnop H_ERRNO_PROTO) \
364 enum nss_status status; \
366 __libc_lock_lock (lock); \
368 /* Reset file pointer to beginning or open file. */ \
369 status = internal_setent (keep_stream); \
371 if (status == NSS_STATUS_SUCCESS) \
373 /* Tell getent function that we have repositioned the file pointer. */ \
376 while ((status = internal_getent (result, buffer, buflen, errnop \
377 H_ERRNO_ARG EXTRA_ARGS_VALUE)) \
378 == NSS_STATUS_SUCCESS) \
382 internal_endent (); \
385 __libc_lock_unlock (lock); \