1 /* Cache handling for group lookup.
2 Copyright (C) 1998-2005, 2006, 2007, 2008 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
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, write to the Free Software Foundation,
18 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
34 #include <sys/socket.h>
35 #include <stackinfo.h>
40 # include <kernel-features.h>
43 /* This is the standard reply in case the service is disabled. */
44 static const gr_response_header disabled =
46 .version = NSCD_VERSION,
54 /* This is the struct describing how to write this record. */
55 const struct iovec grp_iov_disabled =
57 .iov_base = (void *) &disabled,
58 .iov_len = sizeof (disabled)
62 /* This is the standard reply in case we haven't found the dataset. */
63 static const gr_response_header notfound =
65 .version = NSCD_VERSION,
75 cache_addgr (struct database_dyn *db, int fd, request_header *req,
76 const void *key, struct group *grp, uid_t owner,
77 struct hashentry *he, struct datahead *dh, int errval)
81 time_t t = time (NULL);
83 /* We allocate all data in one memory block: the iov vector,
84 the response header and the dataset itself. */
88 gr_response_header resp;
92 assert (offsetof (struct dataset, resp) == offsetof (struct datahead, data));
96 if (he != NULL && errval == EAGAIN)
98 /* If we have an old record available but cannot find one
99 now because the service is not available we keep the old
100 record and make sure it does not get removed. */
101 if (reload_count != UINT_MAX)
102 /* Do not reset the value if we never not reload the record. */
103 dh->nreloads = reload_count - 1;
109 /* We have no data. This means we send the standard reply for this
111 total = sizeof (notfound);
113 written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
116 dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len,
118 /* If we cannot permanently store the result, so be it. */
121 dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
122 dataset->head.recsize = total;
123 dataset->head.notfound = true;
124 dataset->head.nreloads = 0;
125 dataset->head.usable = true;
127 /* Compute the timeout time. */
128 dataset->head.timeout = t + db->negtimeout;
130 /* This is the reply. */
131 memcpy (&dataset->resp, ¬found, total);
133 /* Copy the key data. */
134 memcpy (dataset->strdata, key, req->key_len);
136 /* If necessary, we also propagate the data to disk. */
140 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
141 msync ((void *) pval,
142 ((uintptr_t) dataset & pagesize_m1)
143 + sizeof (struct dataset) + req->key_len, MS_ASYNC);
146 /* Now get the lock to safely insert the records. */
147 pthread_rwlock_rdlock (&db->lock);
149 (void) cache_add (req->type, &dataset->strdata, req->key_len,
150 &dataset->head, true, db, owner);
152 pthread_rwlock_unlock (&db->lock);
154 /* Mark the old entry as obsolete. */
159 ++db->head->addfailed;
164 /* Determine the I/O structure. */
165 size_t gr_name_len = strlen (grp->gr_name) + 1;
166 size_t gr_passwd_len = strlen (grp->gr_passwd) + 1;
167 size_t gr_mem_cnt = 0;
168 uint32_t *gr_mem_len;
169 size_t gr_mem_len_total = 0;
172 const size_t key_len = strlen (key);
173 const size_t buf_len = 3 * sizeof (grp->gr_gid) + key_len + 1;
174 char *buf = alloca (buf_len);
178 /* We need this to insert the `bygid' entry. */
180 n = snprintf (buf, buf_len, "%d%c%n%s", grp->gr_gid, '\0',
181 &key_offset, (char *) key) + 1;
183 /* Determine the length of all members. */
184 while (grp->gr_mem[gr_mem_cnt])
186 gr_mem_len = (uint32_t *) alloca (gr_mem_cnt * sizeof (uint32_t));
187 for (gr_mem_cnt = 0; grp->gr_mem[gr_mem_cnt]; ++gr_mem_cnt)
189 gr_mem_len[gr_mem_cnt] = strlen (grp->gr_mem[gr_mem_cnt]) + 1;
190 gr_mem_len_total += gr_mem_len[gr_mem_cnt];
193 written = total = (sizeof (struct dataset)
194 + gr_mem_cnt * sizeof (uint32_t)
195 + gr_name_len + gr_passwd_len + gr_mem_len_total);
197 /* If we refill the cache, first assume the reconrd did not
198 change. Allocate memory on the cache since it is likely
199 discarded anyway. If it turns out to be necessary to have a
200 new record we can still allocate real memory. */
201 bool alloca_used = false;
206 dataset = (struct dataset *) mempool_alloc (db, total + n,
209 ++db->head->addfailed;
214 /* We cannot permanently add the result in the moment. But
215 we can provide the result as is. Store the data in some
217 dataset = (struct dataset *) alloca (total + n);
219 /* We cannot add this record to the permanent database. */
223 dataset->head.allocsize = total + n;
224 dataset->head.recsize = total - offsetof (struct dataset, resp);
225 dataset->head.notfound = false;
226 dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
227 dataset->head.usable = true;
229 /* Compute the timeout time. */
230 dataset->head.timeout = t + db->postimeout;
232 dataset->resp.version = NSCD_VERSION;
233 dataset->resp.found = 1;
234 dataset->resp.gr_name_len = gr_name_len;
235 dataset->resp.gr_passwd_len = gr_passwd_len;
236 dataset->resp.gr_gid = grp->gr_gid;
237 dataset->resp.gr_mem_cnt = gr_mem_cnt;
239 cp = dataset->strdata;
241 /* This is the member string length array. */
242 cp = mempcpy (cp, gr_mem_len, gr_mem_cnt * sizeof (uint32_t));
244 cp = mempcpy (cp, grp->gr_name, gr_name_len);
245 cp = mempcpy (cp, grp->gr_passwd, gr_passwd_len);
247 for (cnt = 0; cnt < gr_mem_cnt; ++cnt)
248 cp = mempcpy (cp, grp->gr_mem[cnt], gr_mem_len[cnt]);
250 /* Finally the stringified GID value. */
252 char *key_copy = cp + key_offset;
253 assert (key_copy == (char *) rawmemchr (cp, '\0') + 1);
255 /* Now we can determine whether on refill we have to create a new
261 if (total + n == dh->allocsize
262 && total - offsetof (struct dataset, resp) == dh->recsize
263 && memcmp (&dataset->resp, dh->data,
264 dh->allocsize - offsetof (struct dataset, resp)) == 0)
266 /* The data has not changed. We will just bump the
267 timeout value. Note that the new record has been
268 allocated on the stack and need not be freed. */
269 dh->timeout = dataset->head.timeout;
274 /* We have to create a new record. Just allocate
275 appropriate memory and copy it. */
277 = (struct dataset *) mempool_alloc (db, total + n,
281 /* Adjust pointers into the memory block. */
282 gr_name = (char *) newp + (gr_name - (char *) dataset);
283 cp = (char *) newp + (cp - (char *) dataset);
284 key_copy = (char *) newp + (key_copy - (char *) dataset);
286 dataset = memcpy (newp, dataset, total + n);
290 ++db->head->addfailed;
292 /* Mark the old record as obsolete. */
298 /* We write the dataset before inserting it to the database
299 since while inserting this thread might block and so would
300 unnecessarily let the receiver wait. */
304 if (__builtin_expect (db->mmap_used, 1) && !alloca_used)
306 assert (db->wr_fd != -1);
307 assert ((char *) &dataset->resp > (char *) db->data);
308 assert ((char *) &dataset->resp - (char *) db->head
310 <= (sizeof (struct database_pers_head)
311 + db->head->module * sizeof (ref_t)
312 + db->head->data_size));
313 written = sendfileall (fd, db->wr_fd,
314 (char *) &dataset->resp
315 - (char *) db->head, total);
316 # ifndef __ASSUME_SENDFILE
317 if (written == -1 && errno == ENOSYS)
322 # ifndef __ASSUME_SENDFILE
326 written = writeall (fd, &dataset->resp, total);
329 /* Add the record to the database. But only if it has not been
330 stored on the stack. */
333 /* If necessary, we also propagate the data to disk. */
337 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
338 msync ((void *) pval,
339 ((uintptr_t) dataset & pagesize_m1) + total + n,
343 /* Now get the lock to safely insert the records. */
344 pthread_rwlock_rdlock (&db->lock);
346 /* NB: in the following code we always must add the entry
347 marked with FIRST first. Otherwise we end up with
348 dangling "pointers" in case a latter hash entry cannot be
352 /* If the request was by GID, add that entry first. */
353 if (req->type == GETGRBYGID)
355 if (cache_add (GETGRBYGID, cp, key_offset, &dataset->head, true,
361 /* If the key is different from the name add a separate entry. */
362 else if (strcmp (key_copy, gr_name) != 0)
364 if (cache_add (GETGRBYNAME, key_copy, key_len + 1,
365 &dataset->head, true, db, owner) < 0)
371 /* We have to add the value for both, byname and byuid. */
372 if ((req->type == GETGRBYNAME || db->propagate)
373 && __builtin_expect (cache_add (GETGRBYNAME, gr_name,
375 &dataset->head, first, db, owner)
378 if (req->type == GETGRBYNAME && db->propagate)
379 (void) cache_add (GETGRBYGID, cp, key_offset, &dataset->head,
384 pthread_rwlock_unlock (&db->lock);
388 if (__builtin_expect (written != total, 0) && debug_level > 0)
391 dbg_log (_("short write in %s: %s"), __FUNCTION__,
392 strerror_r (errno, buf, sizeof (buf)));
405 lookup (int type, union keytype key, struct group *resultbufp, char *buffer,
406 size_t buflen, struct group **grp)
408 if (type == GETGRBYNAME)
409 return __getgrnam_r (key.v, resultbufp, buffer, buflen, grp);
411 return __getgrgid_r (key.g, resultbufp, buffer, buflen, grp);
416 addgrbyX (struct database_dyn *db, int fd, request_header *req,
417 union keytype key, const char *keystr, uid_t uid,
418 struct hashentry *he, struct datahead *dh)
420 /* Search for the entry matching the key. Please note that we don't
421 look again in the table whether the dataset is now available. We
422 simply insert it. It does not matter if it is in there twice. The
423 pruning function only will look at the timestamp. */
424 size_t buflen = 1024;
425 char *buffer = (char *) alloca (buflen);
426 struct group resultbuf;
428 bool use_malloc = false;
431 if (__builtin_expect (debug_level > 0, 0))
434 dbg_log (_("Haven't found \"%s\" in group cache!"), keystr);
436 dbg_log (_("Reloading \"%s\" in group cache!"), keystr);
439 while (lookup (req->type, key, &resultbuf, buffer, buflen, &grp) != 0
440 && (errval = errno) == ERANGE)
444 if (__builtin_expect (buflen > 32768, 0))
446 char *old_buffer = buffer;
448 buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
451 /* We ran out of memory. We cannot do anything but
452 sending a negative response. In reality this should
457 /* We set the error to indicate this is (possibly) a
458 temporary error and that it does not mean the entry
459 is not available at all. */
466 /* Allocate a new buffer on the stack. If possible combine it
467 with the previously allocated buffer. */
468 buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
471 cache_addgr (db, fd, req, keystr, grp, uid, he, dh, errval);
479 addgrbyname (struct database_dyn *db, int fd, request_header *req,
480 void *key, uid_t uid)
482 union keytype u = { .v = key };
484 addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
489 readdgrbyname (struct database_dyn *db, struct hashentry *he,
497 union keytype u = { .v = db->data + he->key };
499 addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
504 addgrbygid (struct database_dyn *db, int fd, request_header *req,
505 void *key, uid_t uid)
508 gid_t gid = strtoul ((char *) key, &ep, 10);
510 if (*(char *) key == '\0' || *ep != '\0') /* invalid numeric uid */
513 dbg_log (_("Invalid numeric gid \"%s\"!"), (char *) key);
519 union keytype u = { .g = gid };
521 addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
526 readdgrbygid (struct database_dyn *db, struct hashentry *he,
530 gid_t gid = strtoul (db->data + he->key, &ep, 10);
532 /* Since the key has been added before it must be OK. */
533 assert (*(db->data + he->key) != '\0' && *ep == '\0');
540 union keytype u = { .g = gid };
542 addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);