1 /* Cache handling for group lookup.
2 Copyright (C) 1998-2005, 2006 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 version 2 as
8 published by the Free Software Foundation.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
33 #include <sys/socket.h>
34 #include <stackinfo.h>
39 # include <kernel-features.h>
42 /* This is the standard reply in case the service is disabled. */
43 static const gr_response_header disabled =
45 .version = NSCD_VERSION,
53 /* This is the struct describing how to write this record. */
54 const struct iovec grp_iov_disabled =
56 .iov_base = (void *) &disabled,
57 .iov_len = sizeof (disabled)
61 /* This is the standard reply in case we haven't found the dataset. */
62 static const gr_response_header notfound =
64 .version = NSCD_VERSION,
74 cache_addgr (struct database_dyn *db, int fd, request_header *req,
75 const void *key, struct group *grp, uid_t owner,
76 struct hashentry *he, struct datahead *dh, int errval)
80 time_t t = time (NULL);
82 /* We allocate all data in one memory block: the iov vector,
83 the response header and the dataset itself. */
87 gr_response_header resp;
91 assert (offsetof (struct dataset, resp) == offsetof (struct datahead, data));
95 if (he != NULL && errval == EAGAIN)
97 /* If we have an old record available but cannot find one
98 now because the service is not available we keep the old
99 record and make sure it does not get removed. */
100 if (reload_count != UINT_MAX)
101 /* Do not reset the value if we never not reload the record. */
102 dh->nreloads = reload_count - 1;
108 /* We have no data. This means we send the standard reply for this
110 total = sizeof (notfound);
112 written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
115 dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len);
116 /* If we cannot permanently store the result, so be it. */
119 dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
120 dataset->head.recsize = total;
121 dataset->head.notfound = true;
122 dataset->head.nreloads = 0;
123 dataset->head.usable = true;
125 /* Compute the timeout time. */
126 dataset->head.timeout = t + db->negtimeout;
128 /* This is the reply. */
129 memcpy (&dataset->resp, ¬found, total);
131 /* Copy the key data. */
132 memcpy (dataset->strdata, key, req->key_len);
134 /* If necessary, we also propagate the data to disk. */
138 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
139 msync ((void *) pval,
140 ((uintptr_t) dataset & pagesize_m1)
141 + sizeof (struct dataset) + req->key_len, MS_ASYNC);
144 /* Now get the lock to safely insert the records. */
145 pthread_rwlock_rdlock (&db->lock);
147 if (cache_add (req->type, &dataset->strdata, req->key_len,
148 &dataset->head, true, db, owner) < 0)
149 /* Ensure the data can be recovered. */
150 dataset->head.usable = false;
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);
208 ++db->head->addfailed;
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 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 /* Now we can determine whether on refill we have to create a new
260 if (total + n == dh->allocsize
261 && total - offsetof (struct dataset, resp) == dh->recsize
262 && memcmp (&dataset->resp, dh->data,
263 dh->allocsize - offsetof (struct dataset, resp)) == 0)
265 /* The data has not changed. We will just bump the
266 timeout value. Note that the new record has been
267 allocated on the stack and need not be freed. */
268 dh->timeout = dataset->head.timeout;
273 /* We have to create a new record. Just allocate
274 appropriate memory and copy it. */
276 = (struct dataset *) mempool_alloc (db, total + n);
279 /* Adjust pointers into the memory block. */
280 gr_name = (char *) newp + (gr_name - (char *) dataset);
281 cp = (char *) newp + (cp - (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->resp - (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, total);
311 # ifndef __ASSUME_SENDFILE
312 if (written == -1 && errno == ENOSYS)
317 # ifndef __ASSUME_SENDFILE
321 written = writeall (fd, &dataset->resp, total);
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 /* Now get the lock to safely insert the records. */
339 pthread_rwlock_rdlock (&db->lock);
341 /* NB: in the following code we always must add the entry
342 marked with FIRST first. Otherwise we end up with
343 dangling "pointers" in case a latter hash entry cannot be
347 /* If the request was by GID, add that entry first. */
348 if (req->type == GETGRBYGID)
350 if (cache_add (GETGRBYGID, cp, key_offset, &dataset->head, true,
353 /* Could not allocate memory. Make sure the data gets
355 dataset->head.usable = false;
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)
367 /* Could not allocate memory. Make sure the data gets
369 dataset->head.usable = false;
376 /* We have to add the value for both, byname and byuid. */
377 if ((req->type == GETGRBYNAME || db->propagate)
378 && __builtin_expect (cache_add (GETGRBYNAME, gr_name,
380 &dataset->head, first, db, owner)
383 if (req->type == GETGRBYNAME && db->propagate)
384 (void) cache_add (GETGRBYGID, cp, key_offset, &dataset->head,
385 req->type != GETGRBYNAME, db, owner);
388 /* Could not allocate memory. Make sure the data gets
390 dataset->head.usable = false;
393 pthread_rwlock_unlock (&db->lock);
397 if (__builtin_expect (written != total, 0) && debug_level > 0)
400 dbg_log (_("short write in %s: %s"), __FUNCTION__,
401 strerror_r (errno, buf, sizeof (buf)));
414 lookup (int type, union keytype key, struct group *resultbufp, char *buffer,
415 size_t buflen, struct group **grp)
417 if (type == GETGRBYNAME)
418 return __getgrnam_r (key.v, resultbufp, buffer, buflen, grp);
420 return __getgrgid_r (key.g, resultbufp, buffer, buflen, grp);
425 addgrbyX (struct database_dyn *db, int fd, request_header *req,
426 union keytype key, const char *keystr, uid_t uid,
427 struct hashentry *he, struct datahead *dh)
429 /* Search for the entry matching the key. Please note that we don't
430 look again in the table whether the dataset is now available. We
431 simply insert it. It does not matter if it is in there twice. The
432 pruning function only will look at the timestamp. */
433 size_t buflen = 1024;
434 char *buffer = (char *) alloca (buflen);
435 struct group resultbuf;
437 bool use_malloc = false;
440 if (__builtin_expect (debug_level > 0, 0))
443 dbg_log (_("Haven't found \"%s\" in group cache!"), keystr);
445 dbg_log (_("Reloading \"%s\" in group cache!"), keystr);
452 oldeuid = geteuid ();
453 pthread_seteuid_np (uid);
457 while (lookup (req->type, key, &resultbuf, buffer, buflen, &grp) != 0
458 && (errval = errno) == ERANGE)
460 char *old_buffer = buffer;
463 if (__builtin_expect (buflen > 32768, 0))
466 buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
469 /* We ran out of memory. We cannot do anything but
470 sending a negative response. In reality this should
475 /* We set the error to indicate this is (possibly) a
476 temporary error and that it does not mean the entry
477 is not available at all. */
484 /* Allocate a new buffer on the stack. If possible combine it
485 with the previously allocated buffer. */
486 buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
491 pthread_seteuid_np (oldeuid);
494 cache_addgr (db, fd, req, keystr, grp, uid, he, dh, errval);
502 addgrbyname (struct database_dyn *db, int fd, request_header *req,
503 void *key, uid_t uid)
505 union keytype u = { .v = key };
507 addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
512 readdgrbyname (struct database_dyn *db, struct hashentry *he,
520 union keytype u = { .v = db->data + he->key };
522 addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
527 addgrbygid (struct database_dyn *db, int fd, request_header *req,
528 void *key, uid_t uid)
531 gid_t gid = strtoul ((char *) key, &ep, 10);
533 if (*(char *) key == '\0' || *ep != '\0') /* invalid numeric uid */
536 dbg_log (_("Invalid numeric gid \"%s\"!"), (char *) key);
542 union keytype u = { .g = gid };
544 addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
549 readdgrbygid (struct database_dyn *db, struct hashentry *he,
553 gid_t gid = strtoul (db->data + he->key, &ep, 10);
555 /* Since the key has been added before it must be OK. */
556 assert (*(db->data + he->key) != '\0' && *ep == '\0');
563 union keytype u = { .g = gid };
565 addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);