1 /* Cache handling for services lookup.
2 Copyright (C) 2007-2013 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@drepper.com>, 2007.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published
8 by the Free Software Foundation; version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, see <http://www.gnu.org/licenses/>. */
26 #include <kernel-features.h>
32 /* This is the standard reply in case the service is disabled. */
33 static const serv_response_header disabled
=
35 .version
= NSCD_VERSION
,
43 /* This is the struct describing how to write this record. */
44 const struct iovec serv_iov_disabled
=
46 .iov_base
= (void *) &disabled
,
47 .iov_len
= sizeof (disabled
)
51 /* This is the standard reply in case we haven't found the dataset. */
52 static const serv_response_header notfound
=
54 .version
= NSCD_VERSION
,
64 cache_addserv (struct database_dyn
*db
, int fd
, request_header
*req
,
65 const void *key
, struct servent
*serv
, uid_t owner
,
66 struct hashentry
*const he
, struct datahead
*dh
, int errval
)
68 bool all_written
= true;
70 time_t t
= time (NULL
);
72 /* We allocate all data in one memory block: the iov vector,
73 the response header and the dataset itself. */
77 serv_response_header resp
;
81 assert (offsetof (struct dataset
, resp
) == offsetof (struct datahead
, data
));
83 time_t timeout
= MAX_TIMEOUT_VALUE
;
86 if (he
!= NULL
&& errval
== EAGAIN
)
88 /* If we have an old record available but cannot find one
89 now because the service is not available we keep the old
90 record and make sure it does not get removed. */
91 if (reload_count
!= UINT_MAX
)
92 /* Do not reset the value if we never not reload the record. */
93 dh
->nreloads
= reload_count
- 1;
95 /* Reload with the same time-to-live value. */
96 timeout
= dh
->timeout
= t
+ db
->postimeout
;
102 /* We have no data. This means we send the standard reply for this
104 total
= sizeof (notfound
);
107 && TEMP_FAILURE_RETRY (send (fd
, ¬found
, total
,
108 MSG_NOSIGNAL
)) != total
)
111 /* If we have a transient error or cannot permanently store
112 the result, so be it. */
113 if (errval
== EAGAIN
|| __builtin_expect (db
->negtimeout
== 0, 0))
115 /* Mark the old entry as obsolete. */
119 else if ((dataset
= mempool_alloc (db
, (sizeof (struct dataset
)
120 + req
->key_len
), 1)) != NULL
)
122 dataset
->head
.allocsize
= sizeof (struct dataset
) + req
->key_len
;
123 dataset
->head
.recsize
= total
;
124 dataset
->head
.notfound
= true;
125 dataset
->head
.nreloads
= 0;
126 dataset
->head
.usable
= true;
128 /* Compute the timeout time. */
129 timeout
= dataset
->head
.timeout
= t
+ db
->negtimeout
;
131 /* This is the reply. */
132 memcpy (&dataset
->resp
, ¬found
, total
);
134 /* Copy the key data. */
135 memcpy (dataset
->strdata
, key
, req
->key_len
);
137 /* If necessary, we also propagate the data to disk. */
141 uintptr_t pval
= (uintptr_t) dataset
& ~pagesize_m1
;
142 msync ((void *) pval
,
143 ((uintptr_t) dataset
& pagesize_m1
)
144 + sizeof (struct dataset
) + req
->key_len
, MS_ASYNC
);
147 (void) cache_add (req
->type
, &dataset
->strdata
, req
->key_len
,
148 &dataset
->head
, true, db
, owner
, he
== NULL
);
150 pthread_rwlock_unlock (&db
->lock
);
152 /* Mark the old entry as obsolete. */
160 /* Determine the I/O structure. */
161 size_t s_name_len
= strlen (serv
->s_name
) + 1;
162 size_t s_proto_len
= strlen (serv
->s_proto
) + 1;
163 uint32_t *s_aliases_len
;
164 size_t s_aliases_cnt
;
169 /* Determine the number of aliases. */
171 for (cnt
= 0; serv
->s_aliases
[cnt
] != NULL
; ++cnt
)
173 /* Determine the length of all aliases. */
174 s_aliases_len
= (uint32_t *) alloca (s_aliases_cnt
* sizeof (uint32_t));
176 for (cnt
= 0; cnt
< s_aliases_cnt
; ++cnt
)
178 s_aliases_len
[cnt
] = strlen (serv
->s_aliases
[cnt
]) + 1;
179 total
+= s_aliases_len
[cnt
];
182 total
+= (offsetof (struct dataset
, strdata
)
185 + s_aliases_cnt
* sizeof (uint32_t));
187 /* If we refill the cache, first assume the reconrd did not
188 change. Allocate memory on the cache since it is likely
189 discarded anyway. If it turns out to be necessary to have a
190 new record we can still allocate real memory. */
191 bool alloca_used
= false;
195 dataset
= (struct dataset
*) mempool_alloc (db
, total
+ req
->key_len
,
200 /* We cannot permanently add the result in the moment. But
201 we can provide the result as is. Store the data in some
203 dataset
= (struct dataset
*) alloca (total
+ req
->key_len
);
205 /* We cannot add this record to the permanent database. */
209 dataset
->head
.allocsize
= total
+ req
->key_len
;
210 dataset
->head
.recsize
= total
- offsetof (struct dataset
, resp
);
211 dataset
->head
.notfound
= false;
212 dataset
->head
.nreloads
= he
== NULL
? 0 : (dh
->nreloads
+ 1);
213 dataset
->head
.usable
= true;
215 /* Compute the timeout time. */
216 timeout
= dataset
->head
.timeout
= t
+ db
->postimeout
;
218 dataset
->resp
.version
= NSCD_VERSION
;
219 dataset
->resp
.found
= 1;
220 dataset
->resp
.s_name_len
= s_name_len
;
221 dataset
->resp
.s_proto_len
= s_proto_len
;
222 dataset
->resp
.s_port
= serv
->s_port
;
223 dataset
->resp
.s_aliases_cnt
= s_aliases_cnt
;
225 cp
= dataset
->strdata
;
227 cp
= mempcpy (cp
, serv
->s_name
, s_name_len
);
228 cp
= mempcpy (cp
, serv
->s_proto
, s_proto_len
);
229 cp
= mempcpy (cp
, s_aliases_len
, s_aliases_cnt
* sizeof (uint32_t));
231 /* Then the aliases. */
233 for (cnt
= 0; cnt
< s_aliases_cnt
; ++cnt
)
234 cp
= mempcpy (cp
, serv
->s_aliases
[cnt
], s_aliases_len
[cnt
]);
237 == dataset
->strdata
+ total
- offsetof (struct dataset
,
240 char *key_copy
= memcpy (cp
, key
, req
->key_len
);
242 /* Now we can determine whether on refill we have to create a new
248 if (total
+ req
->key_len
== dh
->allocsize
249 && total
- offsetof (struct dataset
, resp
) == dh
->recsize
250 && memcmp (&dataset
->resp
, dh
->data
,
251 dh
->allocsize
- offsetof (struct dataset
, resp
)) == 0)
253 /* The data has not changed. We will just bump the
254 timeout value. Note that the new record has been
255 allocated on the stack and need not be freed. */
256 dh
->timeout
= dataset
->head
.timeout
;
261 /* We have to create a new record. Just allocate
262 appropriate memory and copy it. */
264 = (struct dataset
*) mempool_alloc (db
, total
+ req
->key_len
,
268 /* Adjust pointers into the memory block. */
269 aliases
= (char *) newp
+ (aliases
- (char *) dataset
);
270 assert (key_copy
!= NULL
);
271 key_copy
= (char *) newp
+ (key_copy
- (char *) dataset
);
273 dataset
= memcpy (newp
, dataset
, total
+ req
->key_len
);
277 /* Mark the old record as obsolete. */
283 /* We write the dataset before inserting it to the database
284 since while inserting this thread might block and so would
285 unnecessarily keep the receiver waiting. */
289 if (__builtin_expect (db
->mmap_used
, 1) && !alloca_used
)
291 assert (db
->wr_fd
!= -1);
292 assert ((char *) &dataset
->resp
> (char *) db
->data
);
293 assert ((char *) dataset
- (char *) db
->head
295 <= (sizeof (struct database_pers_head
)
296 + db
->head
->module
* sizeof (ref_t
)
297 + db
->head
->data_size
));
298 ssize_t written
= sendfileall (fd
, db
->wr_fd
,
299 (char *) &dataset
->resp
301 dataset
->head
.recsize
);
302 if (written
!= dataset
->head
.recsize
)
304 # ifndef __ASSUME_SENDFILE
305 if (written
== -1 && errno
== ENOSYS
)
312 # ifndef __ASSUME_SENDFILE
316 if (writeall (fd
, &dataset
->resp
, dataset
->head
.recsize
)
317 != dataset
->head
.recsize
)
321 /* Add the record to the database. But only if it has not been
322 stored on the stack. */
325 /* If necessary, we also propagate the data to disk. */
329 uintptr_t pval
= (uintptr_t) dataset
& ~pagesize_m1
;
330 msync ((void *) pval
,
331 ((uintptr_t) dataset
& pagesize_m1
)
332 + total
+ req
->key_len
, MS_ASYNC
);
335 (void) cache_add (req
->type
, key_copy
, req
->key_len
,
336 &dataset
->head
, true, db
, owner
, he
== NULL
);
338 pthread_rwlock_unlock (&db
->lock
);
342 if (__builtin_expect (!all_written
, 0) && debug_level
> 0)
345 dbg_log (_("short write in %s: %s"), __FUNCTION__
,
346 strerror_r (errno
, buf
, sizeof (buf
)));
354 lookup (int type
, char *key
, struct servent
*resultbufp
, char *buffer
,
355 size_t buflen
, struct servent
**serv
)
357 char *proto
= strrchr (key
, '/');
358 if (proto
!= NULL
&& proto
!= key
)
360 key
= strndupa (key
, proto
- key
);
361 if (proto
[1] == '\0')
367 if (type
== GETSERVBYNAME
)
368 return __getservbyname_r (key
, proto
, resultbufp
, buffer
, buflen
, serv
);
370 assert (type
== GETSERVBYPORT
);
371 return __getservbyport_r (atol (key
), proto
, resultbufp
, buffer
, buflen
,
377 addservbyX (struct database_dyn
*db
, int fd
, request_header
*req
,
378 char *key
, uid_t uid
, struct hashentry
*he
, struct datahead
*dh
)
380 /* Search for the entry matching the key. Please note that we don't
381 look again in the table whether the dataset is now available. We
382 simply insert it. It does not matter if it is in there twice. The
383 pruning function only will look at the timestamp. */
384 size_t buflen
= 1024;
385 char *buffer
= (char *) alloca (buflen
);
386 struct servent resultbuf
;
387 struct servent
*serv
;
388 bool use_malloc
= false;
391 if (__builtin_expect (debug_level
> 0, 0))
394 dbg_log (_("Haven't found \"%s\" in services cache!"), key
);
396 dbg_log (_("Reloading \"%s\" in services cache!"), key
);
399 while (lookup (req
->type
, key
, &resultbuf
, buffer
, buflen
, &serv
) != 0
400 && (errval
= errno
) == ERANGE
)
404 if (__builtin_expect (buflen
> 32768, 0))
406 char *old_buffer
= buffer
;
408 buffer
= (char *) realloc (use_malloc
? buffer
: NULL
, buflen
);
411 /* We ran out of memory. We cannot do anything but
412 sending a negative response. In reality this should
417 /* We set the error to indicate this is (possibly) a
418 temporary error and that it does not mean the entry
419 is not available at all. */
426 /* Allocate a new buffer on the stack. If possible combine it
427 with the previously allocated buffer. */
428 buffer
= (char *) extend_alloca (buffer
, buflen
, 2 * buflen
);
431 time_t timeout
= cache_addserv (db
, fd
, req
, key
, serv
, uid
, he
, dh
, errval
);
441 addservbyname (struct database_dyn
*db
, int fd
, request_header
*req
,
442 void *key
, uid_t uid
)
444 addservbyX (db
, fd
, req
, key
, uid
, NULL
, NULL
);
449 readdservbyname (struct database_dyn
*db
, struct hashentry
*he
,
454 .type
= GETSERVBYNAME
,
458 return addservbyX (db
, -1, &req
, db
->data
+ he
->key
, he
->owner
, he
, dh
);
463 addservbyport (struct database_dyn
*db
, int fd
, request_header
*req
,
464 void *key
, uid_t uid
)
466 addservbyX (db
, fd
, req
, key
, uid
, NULL
, NULL
);
471 readdservbyport (struct database_dyn
*db
, struct hashentry
*he
,
476 .type
= GETSERVBYPORT
,
480 return addservbyX (db
, -1, &req
, db
->data
+ he
->key
, he
->owner
, he
, dh
);