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
202 /* Terminate the line so that we can test for overflow. */
203 ((unsigned char *) curbuf
)[curlen
- 1] = 0xff;
205 char *p
= fgets_unlocked (curbuf
, curlen
, stream
);
207 /* EOF or read error. */
211 /* Done reading in the line. */
212 if (((unsigned char *) curbuf
)[curlen
- 1] == 0xff)
215 /* Drop the terminating '\0'. */
216 remaining_len
-= curlen
- 1;
217 curbuf
+= curlen
- 1;
219 /* fgets copies one less than the input length. Our last iteration is of
220 REMAINING_LEN and once that is done, REMAINING_LEN is decremented by
221 REMAINING_LEN - 1, leaving the result as 1. */
222 while (remaining_len
> 1);
224 /* This means that the current buffer was not large enough. */
228 /* Parsing the database file into `struct STRUCTURE' data structures. */
229 static enum nss_status
230 internal_getent (struct STRUCTURE
*result
,
231 char *buffer
, size_t buflen
, int *errnop H_ERRNO_PROTO
235 struct parser_data
*data
= (void *) buffer
;
236 size_t linebuflen
= buffer
+ buflen
- data
->linebuffer
;
239 if (buflen
< sizeof *data
+ 2)
242 H_ERRNO_SET (NETDB_INTERNAL
);
243 return NSS_STATUS_TRYAGAIN
;
248 get_contents_ret r
= get_contents (data
->linebuffer
, linebuflen
, stream
);
252 /* End of file or read error. */
253 H_ERRNO_SET (HOST_NOT_FOUND
);
254 return NSS_STATUS_NOTFOUND
;
257 if (r
== gcr_overflow
)
259 /* The line is too long. Give the user the opportunity to
260 enlarge the buffer. */
262 H_ERRNO_SET (NETDB_INTERNAL
);
263 return NSS_STATUS_TRYAGAIN
;
266 /* Everything OK. Now skip leading blanks. */
267 p
= data
->linebuffer
;
271 while (*p
== '\0' || *p
== '#' /* Ignore empty and comment lines. */
272 /* Parse the line. If it is invalid, loop to get the next
273 line of the file to parse. */
274 || ! (parse_result
= parse_line (p
, result
, data
, buflen
, errnop
277 if (__glibc_unlikely (parse_result
== -1))
279 H_ERRNO_SET (NETDB_INTERNAL
);
280 return NSS_STATUS_TRYAGAIN
;
283 /* Filled in RESULT with the next entry from the database file. */
284 return NSS_STATUS_SUCCESS
;
288 /* Return the next entry from the database file, doing locking. */
290 CONCAT(_nss_files_get
,ENTNAME_r
) (struct STRUCTURE
*result
, char *buffer
,
291 size_t buflen
, int *errnop H_ERRNO_PROTO
)
293 /* Return next entry in host file. */
294 enum nss_status status
= NSS_STATUS_SUCCESS
;
296 __libc_lock_lock (lock
);
298 /* Be prepared that the set*ent function was not called before. */
301 int save_errno
= errno
;
303 status
= internal_setent (0);
305 __set_errno (save_errno
);
307 if (status
== NSS_STATUS_SUCCESS
&& fgetpos (stream
, &position
) < 0)
311 status
= NSS_STATUS_UNAVAIL
;
315 if (status
== NSS_STATUS_SUCCESS
)
317 /* If the last use was not by the getent function we need the
318 position the stream. */
319 if (last_use
!= getent
)
321 if (fsetpos (stream
, &position
) < 0)
322 status
= NSS_STATUS_UNAVAIL
;
327 if (status
== NSS_STATUS_SUCCESS
)
329 status
= internal_getent (result
, buffer
, buflen
, errnop
330 H_ERRNO_ARG EXTRA_ARGS_VALUE
);
332 /* Remember this position if we were successful. If the
333 operation failed we give the user a chance to repeat the
334 operation (perhaps the buffer was too small). */
335 if (status
== NSS_STATUS_SUCCESS
)
336 fgetpos (stream
, &position
);
338 /* We must make sure we reposition the stream the next call. */
343 __libc_lock_unlock (lock
);
348 /* Macro for defining lookup functions for this file-based database.
350 NAME is the name of the lookup; e.g. `hostbyname'.
352 DB_CHAR, KEYPATTERN, KEYSIZE are ignored here but used by db-XXX.c
353 e.g. `1 + sizeof (id) * 4'.
355 PROTO is the potentially empty list of other parameters.
357 BREAK_IF_MATCH is a block of code which compares `struct STRUCTURE *result'
358 to the lookup key arguments and does `break;' if they match. */
360 #define DB_LOOKUP(name, db_char, keysize, keypattern, break_if_match, proto...)\
362 _nss_files_get##name##_r (proto, \
363 struct STRUCTURE *result, char *buffer, \
364 size_t buflen, int *errnop H_ERRNO_PROTO) \
366 enum nss_status status; \
368 __libc_lock_lock (lock); \
370 /* Reset file pointer to beginning or open file. */ \
371 status = internal_setent (keep_stream); \
373 if (status == NSS_STATUS_SUCCESS) \
375 /* Tell getent function that we have repositioned the file pointer. */ \
378 while ((status = internal_getent (result, buffer, buflen, errnop \
379 H_ERRNO_ARG EXTRA_ARGS_VALUE)) \
380 == NSS_STATUS_SUCCESS) \
384 internal_endent (); \
387 __libc_lock_unlock (lock); \