1 /* Common code for file-based databases in nss_files module.
2 Copyright (C) 1996-2013 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;
182 /* Parsing the database file into `struct STRUCTURE' data structures. */
184 static enum nss_status
185 internal_getent (struct STRUCTURE *result,
186 char *buffer, size_t buflen, int *errnop H_ERRNO_PROTO
190 struct parser_data *data = (void *) buffer;
191 int linebuflen = buffer + buflen - data->linebuffer;
194 if (buflen < sizeof *data + 2)
197 H_ERRNO_SET (NETDB_INTERNAL);
198 return NSS_STATUS_TRYAGAIN;
203 /* Terminate the line so that we can test for overflow. */
204 ((unsigned char *) data->linebuffer)[linebuflen - 1] = '\xff';
206 p = fgets_unlocked (data->linebuffer, linebuflen, stream);
209 /* End of file or read error. */
210 H_ERRNO_SET (HOST_NOT_FOUND);
211 return NSS_STATUS_NOTFOUND;
213 else if (((unsigned char *) data->linebuffer)[linebuflen - 1] != 0xff)
215 /* The line is too long. Give the user the opportunity to
216 enlarge the buffer. */
218 H_ERRNO_SET (NETDB_INTERNAL);
219 return NSS_STATUS_TRYAGAIN;
222 /* Skip leading blanks. */
226 while (*p == '\0' || *p == '#' /* Ignore empty and comment lines. */
227 /* Parse the line. If it is invalid, loop to get the next
228 line of the file to parse. */
229 || ! (parse_result = parse_line (p, result, data, buflen, errnop
232 if (__builtin_expect (parse_result == -1, 0))
234 H_ERRNO_SET (NETDB_INTERNAL);
235 return NSS_STATUS_TRYAGAIN;
238 /* Filled in RESULT with the next entry from the database file. */
239 return NSS_STATUS_SUCCESS;
243 /* Return the next entry from the database file, doing locking. */
245 CONCAT(_nss_files_get,ENTNAME_r) (struct STRUCTURE *result, char *buffer,
246 size_t buflen, int *errnop H_ERRNO_PROTO)
248 /* Return next entry in host file. */
249 enum nss_status status = NSS_STATUS_SUCCESS;
251 __libc_lock_lock (lock);
253 /* Be prepared that the set*ent function was not called before. */
256 int save_errno = errno;
258 status = internal_setent (0);
260 __set_errno (save_errno);
262 if (status == NSS_STATUS_SUCCESS && fgetpos (stream, &position) < 0)
266 status = NSS_STATUS_UNAVAIL;
270 if (status == NSS_STATUS_SUCCESS)
272 /* If the last use was not by the getent function we need the
273 position the stream. */
274 if (last_use != getent)
276 if (fsetpos (stream, &position) < 0)
277 status = NSS_STATUS_UNAVAIL;
282 if (status == NSS_STATUS_SUCCESS)
284 status = internal_getent (result, buffer, buflen, errnop
285 H_ERRNO_ARG EXTRA_ARGS_VALUE);
287 /* Remember this position if we were successful. If the
288 operation failed we give the user a chance to repeat the
289 operation (perhaps the buffer was too small). */
290 if (status == NSS_STATUS_SUCCESS)
291 fgetpos (stream, &position);
293 /* We must make sure we reposition the stream the next call. */
298 __libc_lock_unlock (lock);
303 /* Macro for defining lookup functions for this file-based database.
305 NAME is the name of the lookup; e.g. `hostbyname'.
307 DB_CHAR, KEYPATTERN, KEYSIZE are ignored here but used by db-XXX.c
308 e.g. `1 + sizeof (id) * 4'.
310 PROTO is the potentially empty list of other parameters.
312 BREAK_IF_MATCH is a block of code which compares `struct STRUCTURE *result'
313 to the lookup key arguments and does `break;' if they match. */
315 #define DB_LOOKUP(name, db_char, keysize, keypattern, break_if_match, proto...)\
317 _nss_files_get##name##_r (proto, \
318 struct STRUCTURE *result, char *buffer, \
319 size_t buflen, int *errnop H_ERRNO_PROTO) \
321 enum nss_status status; \
323 __libc_lock_lock (lock); \
325 /* Reset file pointer to beginning or open file. */ \
326 status = internal_setent (keep_stream); \
328 if (status == NSS_STATUS_SUCCESS) \
330 /* Tell getent function that we have repositioned the file pointer. */ \
333 while ((status = internal_getent (result, buffer, buflen, errnop \
334 H_ERRNO_ARG EXTRA_ARGS_VALUE)) \
335 == NSS_STATUS_SUCCESS) \
339 internal_endent (); \
342 __libc_lock_unlock (lock); \