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 dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len,
123 /* If we cannot permanently store the result, so be it. */
126 dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
127 dataset->head.recsize = total;
128 dataset->head.notfound = true;
129 dataset->head.nreloads = 0;
130 dataset->head.usable = true;
132 /* Compute the timeout time. */
133 timeout = dataset->head.timeout = t + db->negtimeout;
135 /* This is the reply. */
136 memcpy (&dataset->resp, ¬found, total);
138 /* Copy the key data. */
139 memcpy (dataset->strdata, key, req->key_len);
141 /* If necessary, we also propagate the data to disk. */
145 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
146 msync ((void *) pval,
147 ((uintptr_t) dataset & pagesize_m1)
148 + sizeof (struct dataset) + req->key_len, MS_ASYNC);
151 (void) cache_add (req->type, &dataset->strdata, req->key_len,
152 &dataset->head, true, db, owner, he == NULL);
154 pthread_rwlock_unlock (&db->lock);
156 /* Mark the old entry as obsolete. */
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 = (offsetof (struct dataset, strdata)
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;
205 dataset = (struct dataset *) mempool_alloc (db, total + n, 1);
209 /* We cannot permanently add the result in the moment. But
210 we can provide the result as is. Store the data in some
212 dataset = (struct dataset *) alloca (total + n);
214 /* We cannot add this record to the permanent database. */
218 dataset->head.allocsize = total + n;
219 dataset->head.recsize = total - offsetof (struct dataset, resp);
220 dataset->head.notfound = false;
221 dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
222 dataset->head.usable = true;
224 /* Compute the timeout time. */
225 timeout = dataset->head.timeout = t + db->postimeout;
227 dataset->resp.version = NSCD_VERSION;
228 dataset->resp.found = 1;
229 dataset->resp.gr_name_len = gr_name_len;
230 dataset->resp.gr_passwd_len = gr_passwd_len;
231 dataset->resp.gr_gid = grp->gr_gid;
232 dataset->resp.gr_mem_cnt = gr_mem_cnt;
234 cp = dataset->strdata;
236 /* This is the member string length array. */
237 cp = mempcpy (cp, gr_mem_len, gr_mem_cnt * sizeof (uint32_t));
239 cp = mempcpy (cp, grp->gr_name, gr_name_len);
240 cp = mempcpy (cp, grp->gr_passwd, gr_passwd_len);
242 for (cnt = 0; cnt < gr_mem_cnt; ++cnt)
243 cp = mempcpy (cp, grp->gr_mem[cnt], gr_mem_len[cnt]);
245 /* Finally the stringified GID value. */
247 char *key_copy = cp + key_offset;
248 assert (key_copy == (char *) rawmemchr (cp, '\0') + 1);
250 assert (cp == dataset->strdata + total - offsetof (struct dataset,
253 /* Now we can determine whether on refill we have to create a new
259 if (total + n == dh->allocsize
260 && total - offsetof (struct dataset, resp) == dh->recsize
261 && memcmp (&dataset->resp, dh->data,
262 dh->allocsize - offsetof (struct dataset, resp)) == 0)
264 /* The data has not changed. We will just bump the
265 timeout value. Note that the new record has been
266 allocated on the stack and need not be freed. */
267 dh->timeout = dataset->head.timeout;
272 /* We have to create a new record. Just allocate
273 appropriate memory and copy it. */
275 = (struct dataset *) mempool_alloc (db, total + n, 1);
278 /* Adjust pointers into the memory block. */
279 gr_name = (char *) newp + (gr_name - (char *) dataset);
280 cp = (char *) newp + (cp - (char *) dataset);
281 key_copy = (char *) newp + (key_copy - (char *) dataset);
283 dataset = memcpy (newp, dataset, total + n);
287 /* Mark the old record as obsolete. */
293 /* We write the dataset before inserting it to the database
294 since while inserting this thread might block and so would
295 unnecessarily let the receiver wait. */
299 if (__builtin_expect (db->mmap_used, 1) && !alloca_used)
301 assert (db->wr_fd != -1);
302 assert ((char *) &dataset->resp > (char *) db->data);
303 assert ((char *) dataset - (char *) db->head
305 <= (sizeof (struct database_pers_head)
306 + db->head->module * sizeof (ref_t)
307 + db->head->data_size));
308 written = sendfileall (fd, db->wr_fd,
309 (char *) &dataset->resp
310 - (char *) db->head, dataset->head.recsize);
311 # ifndef __ASSUME_SENDFILE
312 if (written == -1 && errno == ENOSYS)
317 # ifndef __ASSUME_SENDFILE
321 written = writeall (fd, &dataset->resp, dataset->head.recsize);
324 /* Add the record to the database. But only if it has not been
325 stored on the stack. */
328 /* If necessary, we also propagate the data to disk. */
332 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
333 msync ((void *) pval,
334 ((uintptr_t) dataset & pagesize_m1) + total + n,
338 /* NB: in the following code we always must add the entry
339 marked with FIRST first. Otherwise we end up with
340 dangling "pointers" in case a latter hash entry cannot be
344 /* If the request was by GID, add that entry first. */
345 if (req->type == GETGRBYGID)
347 if (cache_add (GETGRBYGID, cp, key_offset, &dataset->head, true,
348 db, owner, he == NULL) < 0)
353 /* If the key is different from the name add a separate entry. */
354 else if (strcmp (key_copy, gr_name) != 0)
356 if (cache_add (GETGRBYNAME, key_copy, key_len + 1,
357 &dataset->head, true, db, owner, he == NULL) < 0)
363 /* We have to add the value for both, byname and byuid. */
364 if ((req->type == GETGRBYNAME || db->propagate)
365 && __builtin_expect (cache_add (GETGRBYNAME, gr_name,
367 &dataset->head, first, db, owner,
371 if (req->type == GETGRBYNAME && db->propagate)
372 (void) cache_add (GETGRBYGID, cp, key_offset, &dataset->head,
373 false, db, owner, false);
377 pthread_rwlock_unlock (&db->lock);
381 if (__builtin_expect (written != total, 0) && debug_level > 0)
384 dbg_log (_("short write in %s: %s"), __FUNCTION__,
385 strerror_r (errno, buf, sizeof (buf)));
400 lookup (int type, union keytype key, struct group *resultbufp, char *buffer,
401 size_t buflen, struct group **grp)
403 if (type == GETGRBYNAME)
404 return __getgrnam_r (key.v, resultbufp, buffer, buflen, grp);
406 return __getgrgid_r (key.g, resultbufp, buffer, buflen, grp);
411 addgrbyX (struct database_dyn *db, int fd, request_header *req,
412 union keytype key, const char *keystr, uid_t uid,
413 struct hashentry *he, struct datahead *dh)
415 /* Search for the entry matching the key. Please note that we don't
416 look again in the table whether the dataset is now available. We
417 simply insert it. It does not matter if it is in there twice. The
418 pruning function only will look at the timestamp. */
419 size_t buflen = 1024;
420 char *buffer = (char *) alloca (buflen);
421 struct group resultbuf;
423 bool use_malloc = false;
426 if (__builtin_expect (debug_level > 0, 0))
429 dbg_log (_("Haven't found \"%s\" in group cache!"), keystr);
431 dbg_log (_("Reloading \"%s\" in group cache!"), keystr);
434 while (lookup (req->type, key, &resultbuf, buffer, buflen, &grp) != 0
435 && (errval = errno) == ERANGE)
439 if (__builtin_expect (buflen > 32768, 0))
441 char *old_buffer = buffer;
443 buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
446 /* We ran out of memory. We cannot do anything but
447 sending a negative response. In reality this should
452 /* We set the error to indicate this is (possibly) a
453 temporary error and that it does not mean the entry
454 is not available at all. */
461 /* Allocate a new buffer on the stack. If possible combine it
462 with the previously allocated buffer. */
463 buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
466 time_t timeout = cache_addgr (db, fd, req, keystr, grp, uid, he, dh, errval);
476 addgrbyname (struct database_dyn *db, int fd, request_header *req,
477 void *key, uid_t uid)
479 union keytype u = { .v = key };
481 addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
486 readdgrbyname (struct database_dyn *db, struct hashentry *he,
494 union keytype u = { .v = db->data + he->key };
496 return addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
501 addgrbygid (struct database_dyn *db, int fd, request_header *req,
502 void *key, uid_t uid)
505 gid_t gid = strtoul ((char *) key, &ep, 10);
507 if (*(char *) key == '\0' || *ep != '\0') /* invalid numeric uid */
510 dbg_log (_("Invalid numeric gid \"%s\"!"), (char *) key);
516 union keytype u = { .g = gid };
518 addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
523 readdgrbygid (struct database_dyn *db, struct hashentry *he,
527 gid_t gid = strtoul (db->data + he->key, &ep, 10);
529 /* Since the key has been added before it must be OK. */
530 assert (*(db->data + he->key) != '\0' && *ep == '\0');
537 union keytype u = { .g = gid };
539 return addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);