1 /* Cache handling for host lookup.
2 Copyright (C) 2004-2016 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
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/>. */
27 #include <scratch_buffer.h>
32 # include <kernel-features.h>
35 #include "../nss/nsswitch.h"
38 /* Type of the lookup function. */
39 typedef enum nss_status (*initgroups_dyn_function
) (const char *, gid_t
,
40 long int *, long int *,
41 gid_t
**, long int, int *);
44 static const initgr_response_header notfound
=
46 .version
= NSCD_VERSION
,
52 #include "../grp/compat-initgroups.c"
56 addinitgroupsX (struct database_dyn
*db
, int fd
, request_header
*req
,
57 void *key
, uid_t uid
, struct hashentry
*const he
,
60 /* Search for the entry matching the key. Please note that we don't
61 look again in the table whether the dataset is now available. We
62 simply insert it. It does not matter if it is in there twice. The
63 pruning function only will look at the timestamp. */
66 /* We allocate all data in one memory block: the iov vector,
67 the response header and the dataset itself. */
71 initgr_response_header resp
;
75 if (__glibc_unlikely (debug_level
> 0))
78 dbg_log (_("Haven't found \"%s\" in group cache!"), (char *) key
);
80 dbg_log (_("Reloading \"%s\" in group cache!"), (char *) key
);
83 static service_user
*group_database
;
87 if (group_database
== NULL
)
88 no_more
= __nss_database_lookup ("group", NULL
,
89 "compat [NOTFOUND=return] files",
95 /* We always use sysconf even if NGROUPS_MAX is defined. That way, the
96 limit can be raised in the kernel configuration without having to
98 long int limit
= __sysconf (_SC_NGROUPS_MAX
);
102 /* We limit the size of the intially allocated array. */
103 size
= MIN (limit
, 64);
105 /* No fixed limit on groups. Pick a starting buffer size. */
109 bool all_tryagain
= true;
110 bool any_success
= false;
112 /* This is temporary memory, we need not (and must not) call
114 // XXX This really should use alloca. need to change the backends.
115 gid_t
*groups
= (gid_t
*) malloc (size
* sizeof (gid_t
));
116 if (__glibc_unlikely (groups
== NULL
))
117 /* No more memory. */
120 /* Nothing added yet. */
123 long int prev_start
= start
;
124 enum nss_status status
;
125 initgroups_dyn_function fct
;
126 fct
= __nss_lookup_function (nip
, "initgroups_dyn");
130 status
= compat_call (nip
, key
, -1, &start
, &size
, &groups
,
133 if (nss_next_action (nip
, NSS_STATUS_UNAVAIL
) != NSS_ACTION_CONTINUE
)
137 status
= DL_CALL_FCT (fct
, (key
, -1, &start
, &size
, &groups
,
140 /* Remove duplicates. */
141 long int cnt
= prev_start
;
145 for (inner
= 0; inner
< prev_start
; ++inner
)
146 if (groups
[inner
] == groups
[cnt
])
149 if (inner
< prev_start
)
150 groups
[cnt
] = groups
[--start
];
155 if (status
!= NSS_STATUS_TRYAGAIN
)
156 all_tryagain
= false;
158 /* This is really only for debugging. */
159 if (NSS_STATUS_TRYAGAIN
> status
|| status
> NSS_STATUS_RETURN
)
160 __libc_fatal ("illegal status in internal_getgrouplist");
162 any_success
|= status
== NSS_STATUS_SUCCESS
;
164 if (status
!= NSS_STATUS_SUCCESS
165 && nss_next_action (nip
, status
) == NSS_ACTION_RETURN
)
168 if (nip
->next
== NULL
)
179 timeout
= MAX_TIMEOUT_VALUE
;
182 /* Nothing found. Create a negative result record. */
183 total
= sizeof (notfound
);
185 if (he
!= NULL
&& all_tryagain
)
187 /* If we have an old record available but cannot find one now
188 because the service is not available we keep the old record
189 and make sure it does not get removed. */
190 if (reload_count
!= UINT_MAX
&& dh
->nreloads
== reload_count
)
191 /* Do not reset the value if we never not reload the record. */
192 dh
->nreloads
= reload_count
- 1;
194 /* Reload with the same time-to-live value. */
195 timeout
= dh
->timeout
= time (NULL
) + db
->postimeout
;
199 /* We have no data. This means we send the standard reply for this
202 && TEMP_FAILURE_RETRY (send (fd
, ¬found
, total
,
203 MSG_NOSIGNAL
)) != total
)
206 /* If we have a transient error or cannot permanently store
207 the result, so be it. */
208 if (all_tryagain
|| __builtin_expect (db
->negtimeout
== 0, 0))
210 /* Mark the old entry as obsolete. */
214 else if ((dataset
= mempool_alloc (db
, (sizeof (struct dataset
)
215 + req
->key_len
), 1)) != NULL
)
217 timeout
= datahead_init_neg (&dataset
->head
,
218 (sizeof (struct dataset
)
219 + req
->key_len
), total
,
222 /* This is the reply. */
223 memcpy (&dataset
->resp
, ¬found
, total
);
225 /* Copy the key data. */
226 char *key_copy
= memcpy (dataset
->strdata
, key
, req
->key_len
);
228 /* If necessary, we also propagate the data to disk. */
232 uintptr_t pval
= (uintptr_t) dataset
& ~pagesize_m1
;
233 msync ((void *) pval
,
234 ((uintptr_t) dataset
& pagesize_m1
)
235 + sizeof (struct dataset
) + req
->key_len
, MS_ASYNC
);
238 (void) cache_add (req
->type
, key_copy
, req
->key_len
,
239 &dataset
->head
, true, db
, uid
, he
== NULL
);
241 pthread_rwlock_unlock (&db
->lock
);
243 /* Mark the old entry as obsolete. */
252 total
= offsetof (struct dataset
, strdata
) + start
* sizeof (int32_t);
254 /* If we refill the cache, first assume the reconrd did not
255 change. Allocate memory on the cache since it is likely
256 discarded anyway. If it turns out to be necessary to have a
257 new record we can still allocate real memory. */
258 bool alloca_used
= false;
262 dataset
= (struct dataset
*) mempool_alloc (db
, total
+ req
->key_len
,
267 /* We cannot permanently add the result in the moment. But
268 we can provide the result as is. Store the data in some
270 dataset
= (struct dataset
*) alloca (total
+ req
->key_len
);
272 /* We cannot add this record to the permanent database. */
276 timeout
= datahead_init_pos (&dataset
->head
, total
+ req
->key_len
,
277 total
- offsetof (struct dataset
, resp
),
278 he
== NULL
? 0 : dh
->nreloads
+ 1,
281 dataset
->resp
.version
= NSCD_VERSION
;
282 dataset
->resp
.found
= 1;
283 dataset
->resp
.ngrps
= start
;
285 char *cp
= dataset
->strdata
;
287 /* Copy the GID values. If the size of the types match this is
289 if (sizeof (gid_t
) == sizeof (int32_t))
290 cp
= mempcpy (cp
, groups
, start
* sizeof (gid_t
));
293 gid_t
*gcp
= (gid_t
*) cp
;
295 for (int i
= 0; i
< start
; ++i
)
301 /* Finally the user name. */
302 memcpy (cp
, key
, req
->key_len
);
304 assert (cp
== dataset
->strdata
+ total
- offsetof (struct dataset
,
307 /* Now we can determine whether on refill we have to create a new
313 if (total
+ req
->key_len
== dh
->allocsize
314 && total
- offsetof (struct dataset
, resp
) == dh
->recsize
315 && memcmp (&dataset
->resp
, dh
->data
,
316 dh
->allocsize
- offsetof (struct dataset
, resp
)) == 0)
318 /* The data has not changed. We will just bump the
319 timeout value. Note that the new record has been
320 allocated on the stack and need not be freed. */
321 dh
->timeout
= dataset
->head
.timeout
;
326 /* We have to create a new record. Just allocate
327 appropriate memory and copy it. */
329 = (struct dataset
*) mempool_alloc (db
, total
+ req
->key_len
,
333 /* Adjust pointer into the memory block. */
334 cp
= (char *) newp
+ (cp
- (char *) dataset
);
336 dataset
= memcpy (newp
, dataset
, total
+ req
->key_len
);
340 /* Mark the old record as obsolete. */
346 /* We write the dataset before inserting it to the database
347 since while inserting this thread might block and so would
348 unnecessarily let the receiver wait. */
352 if (__builtin_expect (db
->mmap_used
, 1) && !alloca_used
)
354 assert (db
->wr_fd
!= -1);
355 assert ((char *) &dataset
->resp
> (char *) db
->data
);
356 assert ((char *) dataset
- (char *) db
->head
358 <= (sizeof (struct database_pers_head
)
359 + db
->head
->module
* sizeof (ref_t
)
360 + db
->head
->data_size
));
361 ssize_t written
= sendfileall (fd
, db
->wr_fd
,
362 (char *) &dataset
->resp
364 dataset
->head
.recsize
);
365 if (written
!= dataset
->head
.recsize
)
367 # ifndef __ASSUME_SENDFILE
368 if (written
== -1 && errno
== ENOSYS
)
375 # ifndef __ASSUME_SENDFILE
379 if (writeall (fd
, &dataset
->resp
, dataset
->head
.recsize
)
380 != dataset
->head
.recsize
)
385 /* Add the record to the database. But only if it has not been
386 stored on the stack. */
389 /* If necessary, we also propagate the data to disk. */
393 uintptr_t pval
= (uintptr_t) dataset
& ~pagesize_m1
;
394 msync ((void *) pval
,
395 ((uintptr_t) dataset
& pagesize_m1
) + total
+
396 req
->key_len
, MS_ASYNC
);
399 (void) cache_add (INITGROUPS
, cp
, req
->key_len
, &dataset
->head
, true,
400 db
, uid
, he
== NULL
);
402 pthread_rwlock_unlock (&db
->lock
);
408 if (__builtin_expect (!all_written
, 0) && debug_level
> 0)
411 dbg_log (_("short write in %s: %s"), __FUNCTION__
,
412 strerror_r (errno
, buf
, sizeof (buf
)));
420 addinitgroups (struct database_dyn
*db
, int fd
, request_header
*req
, void *key
,
423 addinitgroupsX (db
, fd
, req
, key
, uid
, NULL
, NULL
);
428 readdinitgroups (struct database_dyn
*db
, struct hashentry
*he
,
437 return addinitgroupsX (db
, -1, &req
, db
->data
+ he
->key
, he
->owner
, he
, dh
);