1 /* Cache handling for group lookup.
2 Copyright (C) 1998-2008, 2009 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));
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 (void) cache_add (req->type, &dataset->strdata, req->key_len,
147 &dataset->head, true, db, owner, he == NULL);
149 pthread_rwlock_unlock (&db->lock);
151 /* Mark the old entry as obsolete. */
159 /* Determine the I/O structure. */
160 size_t gr_name_len = strlen (grp->gr_name) + 1;
161 size_t gr_passwd_len = strlen (grp->gr_passwd) + 1;
162 size_t gr_mem_cnt = 0;
163 uint32_t *gr_mem_len;
164 size_t gr_mem_len_total = 0;
167 const size_t key_len = strlen (key);
168 const size_t buf_len = 3 * sizeof (grp->gr_gid) + key_len + 1;
169 char *buf = alloca (buf_len);
173 /* We need this to insert the `bygid' entry. */
175 n = snprintf (buf, buf_len, "%d%c%n%s", grp->gr_gid, '\0',
176 &key_offset, (char *) key) + 1;
178 /* Determine the length of all members. */
179 while (grp->gr_mem[gr_mem_cnt])
181 gr_mem_len = (uint32_t *) alloca (gr_mem_cnt * sizeof (uint32_t));
182 for (gr_mem_cnt = 0; grp->gr_mem[gr_mem_cnt]; ++gr_mem_cnt)
184 gr_mem_len[gr_mem_cnt] = strlen (grp->gr_mem[gr_mem_cnt]) + 1;
185 gr_mem_len_total += gr_mem_len[gr_mem_cnt];
188 written = total = (offsetof (struct dataset, strdata)
189 + gr_mem_cnt * sizeof (uint32_t)
190 + gr_name_len + gr_passwd_len + gr_mem_len_total);
192 /* If we refill the cache, first assume the reconrd did not
193 change. Allocate memory on the cache since it is likely
194 discarded anyway. If it turns out to be necessary to have a
195 new record we can still allocate real memory. */
196 bool alloca_used = false;
200 dataset = (struct dataset *) mempool_alloc (db, total + n, 1);
204 /* We cannot permanently add the result in the moment. But
205 we can provide the result as is. Store the data in some
207 dataset = (struct dataset *) alloca (total + n);
209 /* We cannot add this record to the permanent database. */
213 dataset->head.allocsize = total + n;
214 dataset->head.recsize = total - offsetof (struct dataset, resp);
215 dataset->head.notfound = false;
216 dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
217 dataset->head.usable = true;
219 /* Compute the timeout time. */
220 dataset->head.timeout = t + db->postimeout;
222 dataset->resp.version = NSCD_VERSION;
223 dataset->resp.found = 1;
224 dataset->resp.gr_name_len = gr_name_len;
225 dataset->resp.gr_passwd_len = gr_passwd_len;
226 dataset->resp.gr_gid = grp->gr_gid;
227 dataset->resp.gr_mem_cnt = gr_mem_cnt;
229 cp = dataset->strdata;
231 /* This is the member string length array. */
232 cp = mempcpy (cp, gr_mem_len, gr_mem_cnt * sizeof (uint32_t));
234 cp = mempcpy (cp, grp->gr_name, gr_name_len);
235 cp = mempcpy (cp, grp->gr_passwd, gr_passwd_len);
237 for (cnt = 0; cnt < gr_mem_cnt; ++cnt)
238 cp = mempcpy (cp, grp->gr_mem[cnt], gr_mem_len[cnt]);
240 /* Finally the stringified GID value. */
242 char *key_copy = cp + key_offset;
243 assert (key_copy == (char *) rawmemchr (cp, '\0') + 1);
245 assert (cp == dataset->strdata + total - offsetof (struct dataset,
248 /* Now we can determine whether on refill we have to create a new
254 if (total + n == dh->allocsize
255 && total - offsetof (struct dataset, resp) == dh->recsize
256 && memcmp (&dataset->resp, dh->data,
257 dh->allocsize - offsetof (struct dataset, resp)) == 0)
259 /* The data has not changed. We will just bump the
260 timeout value. Note that the new record has been
261 allocated on the stack and need not be freed. */
262 dh->timeout = dataset->head.timeout;
267 /* We have to create a new record. Just allocate
268 appropriate memory and copy it. */
270 = (struct dataset *) mempool_alloc (db, total + n, 1);
273 /* Adjust pointers into the memory block. */
274 gr_name = (char *) newp + (gr_name - (char *) dataset);
275 cp = (char *) newp + (cp - (char *) dataset);
276 key_copy = (char *) newp + (key_copy - (char *) dataset);
278 dataset = memcpy (newp, dataset, total + n);
282 /* Mark the old record as obsolete. */
288 /* We write the dataset before inserting it to the database
289 since while inserting this thread might block and so would
290 unnecessarily let the receiver wait. */
294 if (__builtin_expect (db->mmap_used, 1) && !alloca_used)
296 assert (db->wr_fd != -1);
297 assert ((char *) &dataset->resp > (char *) db->data);
298 assert ((char *) &dataset->resp - (char *) db->head
300 <= (sizeof (struct database_pers_head)
301 + db->head->module * sizeof (ref_t)
302 + db->head->data_size));
303 written = sendfileall (fd, db->wr_fd,
304 (char *) &dataset->resp
305 - (char *) db->head, total);
306 # ifndef __ASSUME_SENDFILE
307 if (written == -1 && errno == ENOSYS)
312 # ifndef __ASSUME_SENDFILE
316 written = writeall (fd, &dataset->resp, total);
319 /* Add the record to the database. But only if it has not been
320 stored on the stack. */
323 /* If necessary, we also propagate the data to disk. */
327 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
328 msync ((void *) pval,
329 ((uintptr_t) dataset & pagesize_m1) + total + n,
333 /* NB: in the following code we always must add the entry
334 marked with FIRST first. Otherwise we end up with
335 dangling "pointers" in case a latter hash entry cannot be
339 /* If the request was by GID, add that entry first. */
340 if (req->type == GETGRBYGID)
342 if (cache_add (GETGRBYGID, cp, key_offset, &dataset->head, true,
343 db, owner, he == NULL) < 0)
348 /* If the key is different from the name add a separate entry. */
349 else if (strcmp (key_copy, gr_name) != 0)
351 if (cache_add (GETGRBYNAME, key_copy, key_len + 1,
352 &dataset->head, true, db, owner, he == NULL) < 0)
358 /* We have to add the value for both, byname and byuid. */
359 if ((req->type == GETGRBYNAME || db->propagate)
360 && __builtin_expect (cache_add (GETGRBYNAME, gr_name,
362 &dataset->head, first, db, owner,
366 if (req->type == GETGRBYNAME && db->propagate)
367 (void) cache_add (GETGRBYGID, cp, key_offset, &dataset->head,
368 false, db, owner, false);
372 pthread_rwlock_unlock (&db->lock);
376 if (__builtin_expect (written != total, 0) && debug_level > 0)
379 dbg_log (_("short write in %s: %s"), __FUNCTION__,
380 strerror_r (errno, buf, sizeof (buf)));
393 lookup (int type, union keytype key, struct group *resultbufp, char *buffer,
394 size_t buflen, struct group **grp)
396 if (type == GETGRBYNAME)
397 return __getgrnam_r (key.v, resultbufp, buffer, buflen, grp);
399 return __getgrgid_r (key.g, resultbufp, buffer, buflen, grp);
404 addgrbyX (struct database_dyn *db, int fd, request_header *req,
405 union keytype key, const char *keystr, uid_t uid,
406 struct hashentry *he, struct datahead *dh)
408 /* Search for the entry matching the key. Please note that we don't
409 look again in the table whether the dataset is now available. We
410 simply insert it. It does not matter if it is in there twice. The
411 pruning function only will look at the timestamp. */
412 size_t buflen = 1024;
413 char *buffer = (char *) alloca (buflen);
414 struct group resultbuf;
416 bool use_malloc = false;
419 if (__builtin_expect (debug_level > 0, 0))
422 dbg_log (_("Haven't found \"%s\" in group cache!"), keystr);
424 dbg_log (_("Reloading \"%s\" in group cache!"), keystr);
427 while (lookup (req->type, key, &resultbuf, buffer, buflen, &grp) != 0
428 && (errval = errno) == ERANGE)
432 if (__builtin_expect (buflen > 32768, 0))
434 char *old_buffer = buffer;
436 buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
439 /* We ran out of memory. We cannot do anything but
440 sending a negative response. In reality this should
445 /* We set the error to indicate this is (possibly) a
446 temporary error and that it does not mean the entry
447 is not available at all. */
454 /* Allocate a new buffer on the stack. If possible combine it
455 with the previously allocated buffer. */
456 buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
459 cache_addgr (db, fd, req, keystr, grp, uid, he, dh, errval);
467 addgrbyname (struct database_dyn *db, int fd, request_header *req,
468 void *key, uid_t uid)
470 union keytype u = { .v = key };
472 addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
477 readdgrbyname (struct database_dyn *db, struct hashentry *he,
485 union keytype u = { .v = db->data + he->key };
487 addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
492 addgrbygid (struct database_dyn *db, int fd, request_header *req,
493 void *key, uid_t uid)
496 gid_t gid = strtoul ((char *) key, &ep, 10);
498 if (*(char *) key == '\0' || *ep != '\0') /* invalid numeric uid */
501 dbg_log (_("Invalid numeric gid \"%s\"!"), (char *) key);
507 union keytype u = { .g = gid };
509 addgrbyX (db, fd, req, u, key, uid, NULL, NULL);
514 readdgrbygid (struct database_dyn *db, struct hashentry *he,
518 gid_t gid = strtoul (db->data + he->key, &ep, 10);
520 /* Since the key has been added before it must be OK. */
521 assert (*(db->data + he->key) != '\0' && *ep == '\0');
528 union keytype u = { .g = gid };
530 addgrbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);