1 /* Cache handling for group lookup.
2 Copyright (C) 1998-2008, 2009, 2011 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 *const 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));
94 time_t timeout = MAX_TIMEOUT_VALUE;
97 if (he != NULL && errval == EAGAIN)
99 /* If we have an old record available but cannot find one
100 now because the service is not available we keep the old
101 record and make sure it does not get removed. */
102 if (reload_count != UINT_MAX)
103 /* Do not reset the value if we never not reload the record. */
104 dh->nreloads = reload_count - 1;
106 /* Reload with the same time-to-live value. */
107 timeout = dh->timeout = t + db->postimeout;
113 /* We have no data. This means we send the standard reply for this
115 total = sizeof (notfound);
118 written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
121 /* If we cannot permanently store the result, so be it. */
122 if (db->negtimeout == 0)
124 /* Mark the old entry as obsolete. */
128 else if ((dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len, 1)) != NULL)
130 dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
131 dataset->head.recsize = total;
132 dataset->head.notfound = true;
133 dataset->head.nreloads = 0;
134 dataset->head.usable = true;
136 /* Compute the timeout time. */
137 timeout = dataset->head.timeout = t + db->negtimeout;
139 /* This is the reply. */
140 memcpy (&dataset->resp, ¬found, total);
142 /* Copy the key data. */
143 memcpy (dataset->strdata, key, req->key_len);
145 /* If necessary, we also propagate the data to disk. */
149 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
150 msync ((void *) pval,
151 ((uintptr_t) dataset & pagesize_m1)
152 + sizeof (struct dataset) + req->key_len, MS_ASYNC);
155 (void) cache_add (req->type, &dataset->strdata, req->key_len,
156 &dataset->head, true, db, owner, he == NULL);
158 pthread_rwlock_unlock (&db->lock);
160 /* Mark the old entry as obsolete. */
168 /* Determine the I/O structure. */
169 size_t gr_name_len = strlen (grp->gr_name) + 1;
170 size_t gr_passwd_len = strlen (grp->gr_passwd) + 1;
171 size_t gr_mem_cnt = 0;
172 uint32_t *gr_mem_len;
173 size_t gr_mem_len_total = 0;
176 const size_t key_len = strlen (key);
177 const size_t buf_len = 3 * sizeof (grp->gr_gid) + key_len + 1;
178 char *buf = alloca (buf_len);
182 /* We need this to insert the `bygid' entry. */
184 n = snprintf (buf, buf_len, "%d%c%n%s", grp->gr_gid, '\0',
185 &key_offset, (char *) key) + 1;
187 /* Determine the length of all members. */
188 while (grp->gr_mem[gr_mem_cnt])
190 gr_mem_len = (uint32_t *) alloca (gr_mem_cnt * sizeof (uint32_t));
191 for (gr_mem_cnt = 0; grp->gr_mem[gr_mem_cnt]; ++gr_mem_cnt)
193 gr_mem_len[gr_mem_cnt] = strlen (grp->gr_mem[gr_mem_cnt]) + 1;
194 gr_mem_len_total += gr_mem_len[gr_mem_cnt];
197 written = total = (offsetof (struct dataset, strdata)
198 + gr_mem_cnt * sizeof (uint32_t)
199 + gr_name_len + gr_passwd_len + gr_mem_len_total);
201 /* If we refill the cache, first assume the reconrd did not
202 change. Allocate memory on the cache since it is likely
203 discarded anyway. If it turns out to be necessary to have a
204 new record we can still allocate real memory. */
205 bool alloca_used = false;
209 dataset = (struct dataset *) mempool_alloc (db, total + n, 1);
213 /* We cannot permanently add the result in the moment. But
214 we can provide the result as is. Store the data in some
216 dataset = (struct dataset *) alloca (total + n);
218 /* We cannot add this record to the permanent database. */
222 dataset->head.allocsize = total + n;
223 dataset->head.recsize = total - offsetof (struct dataset, resp);
224 dataset->head.notfound = false;
225 dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
226 dataset->head.usable = true;
228 /* Compute the timeout time. */
229 timeout = dataset->head.timeout = t + db->postimeout;
231 dataset->resp.version = NSCD_VERSION;
232 dataset->resp.found = 1;
233 dataset->resp.gr_name_len = gr_name_len;
234 dataset->resp.gr_passwd_len = gr_passwd_len;
235 dataset->resp.gr_gid = grp->gr_gid;
236 dataset->resp.gr_mem_cnt = gr_mem_cnt;
238 cp = dataset->strdata;
240 /* This is the member string length array. */
241 cp = mempcpy (cp, gr_mem_len, gr_mem_cnt * sizeof (uint32_t));
243 cp = mempcpy (cp, grp->gr_name, gr_name_len);
244 cp = mempcpy (cp, grp->gr_passwd, gr_passwd_len);
246 for (cnt = 0; cnt < gr_mem_cnt; ++cnt)
247 cp = mempcpy (cp, grp->gr_mem[cnt], gr_mem_len[cnt]);
249 /* Finally the stringified GID value. */
251 char *key_copy = cp + key_offset;
252 assert (key_copy == (char *) rawmemchr (cp, '\0') + 1);
254 assert (cp == dataset->strdata + total - offsetof (struct dataset,
257 /* Now we can determine whether on refill we have to create a new
263 if (total + n == dh->allocsize
264 && total - offsetof (struct dataset, resp) == dh->recsize
265 && memcmp (&dataset->resp, dh->data,
266 dh->allocsize - offsetof (struct dataset, resp)) == 0)
268 /* The data has not changed. We will just bump the
269 timeout value. Note that the new record has been
270 allocated on the stack and need not be freed. */
271 dh->timeout = dataset->head.timeout;
276 /* We have to create a new record. Just allocate
277 appropriate memory and copy it. */
279 = (struct dataset *) mempool_alloc (db, total + n, 1);
282 /* Adjust pointers into the memory block. */
283 gr_name = (char *) newp + (gr_name - (char *) dataset);
284 cp = (char *) newp + (cp - (char *) dataset);
285 key_copy = (char *) newp + (key_copy - (char *) dataset);
287 dataset = memcpy (newp, dataset, total + n);
291 /* Mark the old record as obsolete. */
297 /* We write the dataset before inserting it to the database
298 since while inserting this thread might block and so would
299 unnecessarily let the receiver wait. */
303 if (__builtin_expect (db->mmap_used, 1) && !alloca_used)
305 assert (db->wr_fd != -1);
306 assert ((char *) &dataset->resp > (char *) db->data);
307 assert ((char *) dataset - (char *) db->head
309 <= (sizeof (struct database_pers_head)
310 + db->head->module * sizeof (ref_t)
311 + db->head->data_size));
312 written = sendfileall (fd, db->wr_fd,
313 (char *) &dataset->resp
314 - (char *) db->head, dataset->head.recsize);
315 # ifndef __ASSUME_SENDFILE
316 if (written == -1 && errno == ENOSYS)
321 # ifndef __ASSUME_SENDFILE
325 written = writeall (fd, &dataset->resp, dataset->head.recsize);
328 /* Add the record to the database. But only if it has not been
329 stored on the stack. */
332 /* If necessary, we also propagate the data to disk. */
336 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
337 msync ((void *) pval,
338 ((uintptr_t) dataset & pagesize_m1) + total + n,
342 /* NB: in the following code we always must add the entry
343 marked with FIRST first. Otherwise we end up with
344 dangling "pointers" in case a latter hash entry cannot be
348 /* If the request was by GID, add that entry first. */
349 if (req->type == GETGRBYGID)
351 if (cache_add (GETGRBYGID, cp, key_offset, &dataset->head, true,
352 db, owner, he == NULL) < 0)
357 /* If the key is different from the name add a separate entry. */
358 else if (strcmp (key_copy, gr_name) != 0)
360 if (cache_add (GETGRBYNAME, key_copy, key_len + 1,
361 &dataset->head, true, db, owner, he == NULL) < 0)
367 /* We have to add the value for both, byname and byuid. */
368 if ((req->type == GETGRBYNAME || db->propagate)
369 && __builtin_expect (cache_add (GETGRBYNAME, gr_name,
371 &dataset->head, first, db, owner,
375 if (req->type == GETGRBYNAME && db->propagate)
376 (void) cache_add (GETGRBYGID, cp, key_offset, &dataset->head,
377 false, db, owner, false);
381 pthread_rwlock_unlock (&db->lock);
385 if (__builtin_expect (written != total, 0) && debug_level > 0)
388 dbg_log (_("short write in %s: %s"), __FUNCTION__,
389 strerror_r (errno, buf, sizeof (buf)));
404 lookup (int type, union keytype key, struct group *resultbufp, char *buffer,
405 size_t buflen, struct group **grp)
407 if (type == GETGRBYNAME)
408 return __getgrnam_r (key.v, resultbufp, buffer, buflen, grp);
410 return __getgrgid_r (key.g, resultbufp, buffer, buflen, grp);
415 addgrbyX (struct database_dyn *db, int fd, request_header *req,
416 union keytype key, const char *keystr, uid_t uid,
417 struct hashentry *he, struct datahead *dh)
419 /* Search for the entry matching the key. Please note that we don't
420 look again in the table whether the dataset is now available. We
421 simply insert it. It does not matter if it is in there twice. The
422 pruning function only will look at the timestamp. */
423 size_t buflen = 1024;
424 char *buffer = (char *) alloca (buflen);
425 struct group resultbuf;
427 bool use_malloc = false;
430 if (__builtin_expect (debug_level > 0, 0))
433 dbg_log (_("Haven't found \"%s\" in group cache!"), keystr);
435 dbg_log (_("Reloading \"%s\" in group cache!"), keystr);
438 while (lookup (req->type, key, &resultbuf, buffer, buflen, &grp) != 0
439 && (errval = errno) == ERANGE)
443 if (__builtin_expect (buflen > 32768, 0))
445 char *old_buffer = buffer;
447 buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
450 /* We ran out of memory. We cannot do anything but
451 sending a negative response. In reality this should
456 /* We set the error to indicate this is (possibly) a
457 temporary error and that it does not mean the entry
458 is not available at all. */
465 /* Allocate a new buffer on the stack. If possible combine it
466 with the previously allocated buffer. */
467 buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
470 time_t timeout = cache_addgr (db, fd, req, keystr, grp, uid, he, dh, errval);
480 addgrbyname (struct database_dyn *db, int fd, request_header *req,
481 void *key, uid_t uid)
483 union keytype u = { .v = key };
485 addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
490 readdgrbyname (struct database_dyn *db, struct hashentry *he,
498 union keytype u = { .v = db->data + he->key };
500 return addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
505 addgrbygid (struct database_dyn *db, int fd, request_header *req,
506 void *key, uid_t uid)
509 gid_t gid = strtoul ((char *) key, &ep, 10);
511 if (*(char *) key == '\0' || *ep != '\0') /* invalid numeric uid */
514 dbg_log (_("Invalid numeric gid \"%s\"!"), (char *) key);
520 union keytype u = { .g = gid };
522 addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
527 readdgrbygid (struct database_dyn *db, struct hashentry *he,
531 gid_t gid = strtoul (db->data + he->key, &ep, 10);
533 /* Since the key has been added before it must be OK. */
534 assert (*(db->data + he->key) != '\0' && *ep == '\0');
541 union keytype u = { .g = gid };
543 return addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);