1 /* Cache handling for services lookup.
2 Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@drepper.com>, 2007.
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. */
27 #include <kernel-features.h>
33 /* This is the standard reply in case the service is disabled. */
34 static const serv_response_header disabled =
36 .version = NSCD_VERSION,
44 /* This is the struct describing how to write this record. */
45 const struct iovec serv_iov_disabled =
47 .iov_base = (void *) &disabled,
48 .iov_len = sizeof (disabled)
52 /* This is the standard reply in case we haven't found the dataset. */
53 static const serv_response_header notfound =
55 .version = NSCD_VERSION,
65 cache_addserv (struct database_dyn *db, int fd, request_header *req,
66 const void *key, struct servent *serv, uid_t owner,
67 struct hashentry *const he, struct datahead *dh, int errval)
71 time_t t = time (NULL);
73 /* We allocate all data in one memory block: the iov vector,
74 the response header and the dataset itself. */
78 serv_response_header resp;
82 assert (offsetof (struct dataset, resp) == offsetof (struct datahead, data));
86 if (he != NULL && errval == EAGAIN)
88 /* If we have an old record available but cannot find one
89 now because the service is not available we keep the old
90 record and make sure it does not get removed. */
91 if (reload_count != UINT_MAX)
92 /* Do not reset the value if we never not reload the record. */
93 dh->nreloads = reload_count - 1;
99 /* We have no data. This means we send the standard reply for this
101 total = sizeof (notfound);
103 written = TEMP_FAILURE_RETRY (send (fd, ¬found, total,
106 dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len,
108 /* If we cannot permanently store the result, so be it. */
111 dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
112 dataset->head.recsize = total;
113 dataset->head.notfound = true;
114 dataset->head.nreloads = 0;
115 dataset->head.usable = true;
117 /* Compute the timeout time. */
118 dataset->head.timeout = t + db->negtimeout;
120 /* This is the reply. */
121 memcpy (&dataset->resp, ¬found, total);
123 /* Copy the key data. */
124 memcpy (dataset->strdata, key, req->key_len);
126 /* If necessary, we also propagate the data to disk. */
130 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
131 msync ((void *) pval,
132 ((uintptr_t) dataset & pagesize_m1)
133 + sizeof (struct dataset) + req->key_len, MS_ASYNC);
136 (void) cache_add (req->type, &dataset->strdata, req->key_len,
137 &dataset->head, true, db, owner, he == NULL);
139 /* Mark the old entry as obsolete. */
147 /* Determine the I/O structure. */
148 size_t s_name_len = strlen (serv->s_name) + 1;
149 size_t s_proto_len = strlen (serv->s_proto) + 1;
150 uint32_t *s_aliases_len;
151 size_t s_aliases_cnt;
156 /* Determine the number of aliases. */
158 for (cnt = 0; serv->s_aliases[cnt] != NULL; ++cnt)
160 /* Determine the length of all aliases. */
161 s_aliases_len = (uint32_t *) alloca (s_aliases_cnt * sizeof (uint32_t));
163 for (cnt = 0; cnt < s_aliases_cnt; ++cnt)
165 s_aliases_len[cnt] = strlen (serv->s_aliases[cnt]) + 1;
166 total += s_aliases_len[cnt];
169 total += (offsetof (struct dataset, strdata)
172 + s_aliases_cnt * sizeof (uint32_t));
175 /* If we refill the cache, first assume the reconrd did not
176 change. Allocate memory on the cache since it is likely
177 discarded anyway. If it turns out to be necessary to have a
178 new record we can still allocate real memory. */
179 bool alloca_used = false;
183 dataset = (struct dataset *) mempool_alloc (db, total + req->key_len,
188 /* We cannot permanently add the result in the moment. But
189 we can provide the result as is. Store the data in some
191 dataset = (struct dataset *) alloca (total + req->key_len);
193 /* We cannot add this record to the permanent database. */
197 dataset->head.allocsize = total + req->key_len;
198 dataset->head.recsize = total - offsetof (struct dataset, resp);
199 dataset->head.notfound = false;
200 dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
201 dataset->head.usable = true;
203 /* Compute the timeout time. */
204 dataset->head.timeout = t + db->postimeout;
206 dataset->resp.version = NSCD_VERSION;
207 dataset->resp.found = 1;
208 dataset->resp.s_name_len = s_name_len;
209 dataset->resp.s_proto_len = s_proto_len;
210 dataset->resp.s_port = serv->s_port;
211 dataset->resp.s_aliases_cnt = s_aliases_cnt;
213 cp = dataset->strdata;
215 cp = mempcpy (cp, serv->s_name, s_name_len);
216 cp = mempcpy (cp, serv->s_proto, s_proto_len);
217 cp = mempcpy (cp, s_aliases_len, s_aliases_cnt * sizeof (uint32_t));
219 /* Then the aliases. */
221 for (cnt = 0; cnt < s_aliases_cnt; ++cnt)
222 cp = mempcpy (cp, serv->s_aliases[cnt], s_aliases_len[cnt]);
225 == dataset->strdata + total - offsetof (struct dataset,
228 char *key_copy = memcpy (cp, key, req->key_len);
230 /* Now we can determine whether on refill we have to create a new
236 if (total + req->key_len == dh->allocsize
237 && total - offsetof (struct dataset, resp) == dh->recsize
238 && memcmp (&dataset->resp, dh->data,
239 dh->allocsize - offsetof (struct dataset, resp)) == 0)
241 /* The data has not changed. We will just bump the
242 timeout value. Note that the new record has been
243 allocated on the stack and need not be freed. */
244 dh->timeout = dataset->head.timeout;
249 /* We have to create a new record. Just allocate
250 appropriate memory and copy it. */
252 = (struct dataset *) mempool_alloc (db, total + req->key_len,
256 /* Adjust pointers into the memory block. */
257 aliases = (char *) newp + (aliases - (char *) dataset);
258 assert (key_copy != NULL);
259 key_copy = (char *) newp + (key_copy - (char *) dataset);
261 dataset = memcpy (newp, dataset, total + req->key_len);
265 /* Mark the old record as obsolete. */
271 /* We write the dataset before inserting it to the database
272 since while inserting this thread might block and so would
273 unnecessarily keep the receiver waiting. */
277 if (__builtin_expect (db->mmap_used, 1) && !alloca_used)
279 assert (db->wr_fd != -1);
280 assert ((char *) &dataset->resp > (char *) db->data);
281 assert ((char *) &dataset->resp - (char *) db->head
283 <= (sizeof (struct database_pers_head)
284 + db->head->module * sizeof (ref_t)
285 + db->head->data_size));
286 written = sendfileall (fd, db->wr_fd,
287 (char *) &dataset->resp
288 - (char *) db->head, total);
289 # ifndef __ASSUME_SENDFILE
290 if (written == -1 && errno == ENOSYS)
295 # ifndef __ASSUME_SENDFILE
299 written = writeall (fd, &dataset->resp, total);
302 /* Add the record to the database. But only if it has not been
303 stored on the stack. */
306 /* If necessary, we also propagate the data to disk. */
310 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
311 msync ((void *) pval,
312 ((uintptr_t) dataset & pagesize_m1)
313 + total + req->key_len, MS_ASYNC);
316 (void) cache_add (req->type, key_copy, req->key_len,
317 &dataset->head, true, db, owner, he == NULL);
321 if (__builtin_expect (written != total, 0) && debug_level > 0)
324 dbg_log (_("short write in %s: %s"), __FUNCTION__,
325 strerror_r (errno, buf, sizeof (buf)));
331 lookup (int type, char *key, struct servent *resultbufp, char *buffer,
332 size_t buflen, struct servent **serv)
334 char *proto = strrchr (key, '/');
335 if (proto != NULL && proto != key)
337 key = strndupa (key, proto - key);
338 if (proto[1] == '\0')
344 if (type == GETSERVBYNAME)
345 return __getservbyname_r (key, proto, resultbufp, buffer, buflen, serv);
347 assert (type == GETSERVBYPORT);
348 return __getservbyport_r (atol (key), proto, resultbufp, buffer, buflen,
354 addservbyX (struct database_dyn *db, int fd, request_header *req,
355 char *key, uid_t uid, struct hashentry *he, struct datahead *dh)
357 /* Search for the entry matching the key. Please note that we don't
358 look again in the table whether the dataset is now available. We
359 simply insert it. It does not matter if it is in there twice. The
360 pruning function only will look at the timestamp. */
361 size_t buflen = 1024;
362 char *buffer = (char *) alloca (buflen);
363 struct servent resultbuf;
364 struct servent *serv;
365 bool use_malloc = false;
368 if (__builtin_expect (debug_level > 0, 0))
371 dbg_log (_("Haven't found \"%s\" in services cache!"), key);
373 dbg_log (_("Reloading \"%s\" in services cache!"), key);
376 while (lookup (req->type, key, &resultbuf, buffer, buflen, &serv) != 0
377 && (errval = errno) == ERANGE)
381 if (__builtin_expect (buflen > 32768, 0))
383 char *old_buffer = buffer;
385 buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
388 /* We ran out of memory. We cannot do anything but
389 sending a negative response. In reality this should
394 /* We set the error to indicate this is (possibly) a
395 temporary error and that it does not mean the entry
396 is not available at all. */
403 /* Allocate a new buffer on the stack. If possible combine it
404 with the previously allocated buffer. */
405 buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
408 cache_addserv (db, fd, req, key, serv, uid, he, dh, errval);
416 addservbyname (struct database_dyn *db, int fd, request_header *req,
417 void *key, uid_t uid)
419 addservbyX (db, fd, req, key, uid, NULL, NULL);
424 readdservbyname (struct database_dyn *db, struct hashentry *he,
429 .type = GETSERVBYNAME,
433 addservbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);
438 addservbyport (struct database_dyn *db, int fd, request_header *req,
439 void *key, uid_t uid)
441 addservbyX (db, fd, req, key, uid, NULL, NULL);
446 readdservbyport (struct database_dyn *db, struct hashentry *he,
451 .type = GETSERVBYPORT,
455 addservbyX (db, -1, &req, db->data + he->key, he->owner, he, dh);