1 /* Cache handling for host lookup.
2 Copyright (C) 2004, 2005 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library 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 GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
32 #include "../nss/nsswitch.h"
35 /* Type of the lookup function. */
36 typedef enum nss_status (*initgroups_dyn_function) (const char *, gid_t,
37 long int *, long int *,
38 gid_t **, long int, int *);
41 static const initgr_response_header notfound =
43 .version = NSCD_VERSION,
49 #include "../grp/compat-initgroups.c"
53 addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
54 void *key, uid_t uid, struct hashentry *he,
57 /* Search for the entry matching the key. Please note that we don't
58 look again in the table whether the dataset is now available. We
59 simply insert it. It does not matter if it is in there twice. The
60 pruning function only will look at the timestamp. */
63 /* We allocate all data in one memory block: the iov vector,
64 the response header and the dataset itself. */
68 initgr_response_header resp;
72 if (__builtin_expect (debug_level > 0, 0))
75 dbg_log (_("Haven't found \"%s\" in group cache!"), (char *) key);
77 dbg_log (_("Reloading \"%s\" in group cache!"), (char *) key);
80 static service_user *group_database;
81 service_user *nip = NULL;
84 if (group_database != NULL)
90 no_more = __nss_database_lookup ("group", NULL,
91 "compat [NOTFOUND=return] files", &nip);
93 /* We always use sysconf even if NGROUPS_MAX is defined. That way, the
94 limit can be raised in the kernel configuration without having to
96 long int limit = __sysconf (_SC_NGROUPS_MAX);
100 /* We limit the size of the intially allocated array. */
101 size = MIN (limit, 64);
103 /* No fixed limit on groups. Pick a starting buffer size. */
107 bool all_tryagain = true;
109 /* This is temporary memory, we need not (ad must not) call
111 // XXX This really should use alloca. need to change the backends.
112 gid_t *groups = (gid_t *) malloc (size * sizeof (gid_t));
113 if (__builtin_expect (groups == NULL, 0))
114 /* No more memory. */
117 /* Nothing added yet. */
120 long int prev_start = start;
121 enum nss_status status;
122 initgroups_dyn_function fct;
123 fct = __nss_lookup_function (nip, "initgroups_dyn");
127 status = compat_call (nip, key, -1, &start, &size, &groups,
130 if (nss_next_action (nip, NSS_STATUS_UNAVAIL) != NSS_ACTION_CONTINUE)
134 status = DL_CALL_FCT (fct, (key, -1, &start, &size, &groups,
137 /* Remove duplicates. */
138 long int cnt = prev_start;
142 for (inner = 0; inner < prev_start; ++inner)
143 if (groups[inner] == groups[cnt])
146 if (inner < prev_start)
147 groups[cnt] = groups[--start];
152 if (status != NSS_STATUS_TRYAGAIN)
153 all_tryagain = false;
155 /* This is really only for debugging. */
156 if (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_RETURN)
157 __libc_fatal ("illegal status in internal_getgrouplist");
159 if (status != NSS_STATUS_SUCCESS
160 && nss_next_action (nip, status) == NSS_ACTION_RETURN)
163 if (nip->next == NULL)
174 /* Nothing found. Create a negative result record. */
175 written = total = sizeof (notfound);
177 if (he != NULL && all_tryagain)
179 /* If we have an old record available but cannot find one now
180 because the service is not available we keep the old record
181 and make sure it does not get removed. */
182 if (reload_count != UINT_MAX && dh->nreloads == reload_count)
183 /* Do not reset the value if we never not reload the record. */
184 dh->nreloads = reload_count - 1;
188 /* We have no data. This means we send the standard reply for this
191 written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
194 dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len);
195 /* If we cannot permanently store the result, so be it. */
198 dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
199 dataset->head.recsize = total;
200 dataset->head.notfound = true;
201 dataset->head.nreloads = 0;
202 dataset->head.usable = true;
204 /* Compute the timeout time. */
205 dataset->head.timeout = time (NULL) + db->negtimeout;
207 /* This is the reply. */
208 memcpy (&dataset->resp, ¬found, total);
210 /* Copy the key data. */
211 char *key_copy = memcpy (dataset->strdata, key, req->key_len);
213 /* If necessary, we also propagate the data to disk. */
217 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
218 msync ((void *) pval,
219 ((uintptr_t) dataset & pagesize_m1)
220 + sizeof (struct dataset) + req->key_len, MS_ASYNC);
223 /* Now get the lock to safely insert the records. */
224 pthread_rwlock_rdlock (&db->lock);
226 if (cache_add (req->type, key_copy, req->key_len,
227 &dataset->head, true, db, uid) < 0)
228 /* Ensure the data can be recovered. */
229 dataset->head.usable = false;
231 pthread_rwlock_unlock (&db->lock);
233 /* Mark the old entry as obsolete. */
238 ++db->head->addfailed;
244 written = total = sizeof (struct dataset) + start * sizeof (int32_t);
246 /* If we refill the cache, first assume the reconrd did not
247 change. Allocate memory on the cache since it is likely
248 discarded anyway. If it turns out to be necessary to have a
249 new record we can still allocate real memory. */
250 bool alloca_used = false;
255 dataset = (struct dataset *) mempool_alloc (db,
256 total + req->key_len);
258 ++db->head->addfailed;
263 /* We cannot permanently add the result in the moment. But
264 we can provide the result as is. Store the data in some
266 dataset = (struct dataset *) alloca (total + req->key_len);
268 /* We cannot add this record to the permanent database. */
272 dataset->head.allocsize = total + req->key_len;
273 dataset->head.recsize = total - offsetof (struct dataset, resp);
274 dataset->head.notfound = false;
275 dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
276 dataset->head.usable = true;
278 /* Compute the timeout time. */
279 dataset->head.timeout = time (NULL) + db->postimeout;
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 /* Now we can determine whether on refill we have to create a new
310 if (total + req->key_len == dh->allocsize
311 && total - offsetof (struct dataset, resp) == dh->recsize
312 && memcmp (&dataset->resp, dh->data,
313 dh->allocsize - offsetof (struct dataset, resp)) == 0)
315 /* The data has not changed. We will just bump the
316 timeout value. Note that the new record has been
317 allocated on the stack and need not be freed. */
318 dh->timeout = dataset->head.timeout;
323 /* We have to create a new record. Just allocate
324 appropriate memory and copy it. */
326 = (struct dataset *) mempool_alloc (db, total + req->key_len);
329 /* Adjust pointer into the memory block. */
330 cp = (char *) newp + (cp - (char *) dataset);
332 dataset = memcpy (newp, dataset, total + req->key_len);
336 /* Mark the old record as obsolete. */
342 /* We write the dataset before inserting it to the database
343 since while inserting this thread might block and so would
344 unnecessarily let the receiver wait. */
347 written = writeall (fd, &dataset->resp, total);
351 /* Add the record to the database. But only if it has not been
352 stored on the stack. */
355 /* If necessary, we also propagate the data to disk. */
359 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
360 msync ((void *) pval,
361 ((uintptr_t) dataset & pagesize_m1) + total +
362 req->key_len, MS_ASYNC);
365 /* Now get the lock to safely insert the records. */
366 pthread_rwlock_rdlock (&db->lock);
368 if (cache_add (INITGROUPS, cp, req->key_len, &dataset->head, true,
370 /* Could not allocate memory. Make sure the data gets
372 dataset->head.usable = false;
374 pthread_rwlock_unlock (&db->lock);
380 if (__builtin_expect (written != total, 0) && debug_level > 0)
383 dbg_log (_("short write in %s: %s"), __FUNCTION__,
384 strerror_r (errno, buf, sizeof (buf)));
390 addinitgroups (struct database_dyn *db, int fd, request_header *req, void *key,
393 addinitgroupsX (db, fd, req, key, uid, NULL, NULL);
398 readdinitgroups (struct database_dyn *db, struct hashentry *he,
407 addinitgroupsX (db, -1, &req, db->data + he->key, he->owner, he, dh);