* elf/soinit.c (__EH_FRAME_BEGIN__): Remove.
[glibc/pb-stable.git] / nscd / pwdcache.c
blob4a0cabd2409ef65cec01ff17c3c0c03a3410c0c2
1 /* Cache handling for passwd lookup.
2 Copyright (C) 1998-2005, 2006, 2007, 2008 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. */
20 #include <alloca.h>
21 #include <assert.h>
22 #include <errno.h>
23 #include <error.h>
24 #include <libintl.h>
25 #include <pwd.h>
26 #include <stdbool.h>
27 #include <stddef.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <time.h>
32 #include <unistd.h>
33 #include <sys/mman.h>
34 #include <sys/socket.h>
35 #include <stackinfo.h>
37 #include "nscd.h"
38 #include "dbg_log.h"
39 #ifdef HAVE_SENDFILE
40 # include <kernel-features.h>
41 #endif
43 /* This is the standard reply in case the service is disabled. */
44 static const pw_response_header disabled =
46 .version = NSCD_VERSION,
47 .found = -1,
48 .pw_name_len = 0,
49 .pw_passwd_len = 0,
50 .pw_uid = -1,
51 .pw_gid = -1,
52 .pw_gecos_len = 0,
53 .pw_dir_len = 0,
54 .pw_shell_len = 0
57 /* This is the struct describing how to write this record. */
58 const struct iovec pwd_iov_disabled =
60 .iov_base = (void *) &disabled,
61 .iov_len = sizeof (disabled)
65 /* This is the standard reply in case we haven't found the dataset. */
66 static const pw_response_header notfound =
68 .version = NSCD_VERSION,
69 .found = 0,
70 .pw_name_len = 0,
71 .pw_passwd_len = 0,
72 .pw_uid = -1,
73 .pw_gid = -1,
74 .pw_gecos_len = 0,
75 .pw_dir_len = 0,
76 .pw_shell_len = 0
80 static void
81 cache_addpw (struct database_dyn *db, int fd, request_header *req,
82 const void *key, struct passwd *pwd, uid_t owner,
83 struct hashentry *he, struct datahead *dh, int errval)
85 ssize_t total;
86 ssize_t written;
87 time_t t = time (NULL);
89 /* We allocate all data in one memory block: the iov vector,
90 the response header and the dataset itself. */
91 struct dataset
93 struct datahead head;
94 pw_response_header resp;
95 char strdata[0];
96 } *dataset;
98 assert (offsetof (struct dataset, resp) == offsetof (struct datahead, data));
100 if (pwd == NULL)
102 if (he != NULL && errval == EAGAIN)
104 /* If we have an old record available but cannot find one
105 now because the service is not available we keep the old
106 record and make sure it does not get removed. */
107 if (reload_count != UINT_MAX && dh->nreloads == reload_count)
108 /* Do not reset the value if we never not reload the record. */
109 dh->nreloads = reload_count - 1;
111 written = total = 0;
113 else
115 /* We have no data. This means we send the standard reply for this
116 case. */
117 written = total = sizeof (notfound);
119 if (fd != -1)
120 written = TEMP_FAILURE_RETRY (send (fd, &notfound, total,
121 MSG_NOSIGNAL));
123 dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len,
124 IDX_result_data);
125 /* If we cannot permanently store the result, so be it. */
126 if (dataset != NULL)
128 dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
129 dataset->head.recsize = total;
130 dataset->head.notfound = true;
131 dataset->head.nreloads = 0;
132 dataset->head.usable = true;
134 /* Compute the timeout time. */
135 dataset->head.timeout = t + db->negtimeout;
137 /* This is the reply. */
138 memcpy (&dataset->resp, &notfound, total);
140 /* Copy the key data. */
141 char *key_copy = memcpy (dataset->strdata, key, req->key_len);
143 /* If necessary, we also propagate the data to disk. */
144 if (db->persistent)
146 // XXX async OK?
147 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
148 msync ((void *) pval,
149 ((uintptr_t) dataset & pagesize_m1)
150 + sizeof (struct dataset) + req->key_len, MS_ASYNC);
153 /* Now get the lock to safely insert the records. */
154 pthread_rwlock_rdlock (&db->lock);
156 (void) cache_add (req->type, key_copy, req->key_len,
157 &dataset->head, true, db, owner, he == NULL);
159 pthread_rwlock_unlock (&db->lock);
161 /* Mark the old entry as obsolete. */
162 if (dh != NULL)
163 dh->usable = false;
165 else
166 ++db->head->addfailed;
169 else
171 /* Determine the I/O structure. */
172 size_t pw_name_len = strlen (pwd->pw_name) + 1;
173 size_t pw_passwd_len = strlen (pwd->pw_passwd) + 1;
174 size_t pw_gecos_len = strlen (pwd->pw_gecos) + 1;
175 size_t pw_dir_len = strlen (pwd->pw_dir) + 1;
176 size_t pw_shell_len = strlen (pwd->pw_shell) + 1;
177 char *cp;
178 const size_t key_len = strlen (key);
179 const size_t buf_len = 3 * sizeof (pwd->pw_uid) + key_len + 1;
180 char *buf = alloca (buf_len);
181 ssize_t n;
183 /* We need this to insert the `byuid' entry. */
184 int key_offset;
185 n = snprintf (buf, buf_len, "%d%c%n%s", pwd->pw_uid, '\0',
186 &key_offset, (char *) key) + 1;
188 written = total = (sizeof (struct dataset) + pw_name_len + pw_passwd_len
189 + pw_gecos_len + pw_dir_len + pw_shell_len);
191 /* If we refill the cache, first assume the reconrd did not
192 change. Allocate memory on the cache since it is likely
193 discarded anyway. If it turns out to be necessary to have a
194 new record we can still allocate real memory. */
195 bool alloca_used = false;
196 dataset = NULL;
198 if (he == NULL)
200 dataset = (struct dataset *) mempool_alloc (db, total + n,
201 IDX_result_data);
202 if (dataset == NULL)
203 ++db->head->addfailed;
206 if (dataset == NULL)
208 /* We cannot permanently add the result in the moment. But
209 we can provide the result as is. Store the data in some
210 temporary memory. */
211 dataset = (struct dataset *) alloca (total + n);
213 /* We cannot add this record to the permanent database. */
214 alloca_used = true;
217 dataset->head.allocsize = total + n;
218 dataset->head.recsize = total - offsetof (struct dataset, resp);
219 dataset->head.notfound = false;
220 dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
221 dataset->head.usable = true;
223 /* Compute the timeout time. */
224 dataset->head.timeout = t + db->postimeout;
226 dataset->resp.version = NSCD_VERSION;
227 dataset->resp.found = 1;
228 dataset->resp.pw_name_len = pw_name_len;
229 dataset->resp.pw_passwd_len = pw_passwd_len;
230 dataset->resp.pw_uid = pwd->pw_uid;
231 dataset->resp.pw_gid = pwd->pw_gid;
232 dataset->resp.pw_gecos_len = pw_gecos_len;
233 dataset->resp.pw_dir_len = pw_dir_len;
234 dataset->resp.pw_shell_len = pw_shell_len;
236 cp = dataset->strdata;
238 /* Copy the strings over into the buffer. */
239 cp = mempcpy (cp, pwd->pw_name, pw_name_len);
240 cp = mempcpy (cp, pwd->pw_passwd, pw_passwd_len);
241 cp = mempcpy (cp, pwd->pw_gecos, pw_gecos_len);
242 cp = mempcpy (cp, pwd->pw_dir, pw_dir_len);
243 cp = mempcpy (cp, pwd->pw_shell, pw_shell_len);
245 /* Finally the stringified UID value. */
246 memcpy (cp, buf, n);
247 char *key_copy = cp + key_offset;
248 assert (key_copy == (char *) rawmemchr (cp, '\0') + 1);
250 /* Now we can determine whether on refill we have to create a new
251 record or not. */
252 if (he != NULL)
254 assert (fd == -1);
256 if (total + n == dh->allocsize
257 && total - offsetof (struct dataset, resp) == dh->recsize
258 && memcmp (&dataset->resp, dh->data,
259 dh->allocsize - offsetof (struct dataset, resp)) == 0)
261 /* The data has not changed. We will just bump the
262 timeout value. Note that the new record has been
263 allocated on the stack and need not be freed. */
264 dh->timeout = dataset->head.timeout;
265 ++dh->nreloads;
267 else
269 /* We have to create a new record. Just allocate
270 appropriate memory and copy it. */
271 struct dataset *newp
272 = (struct dataset *) mempool_alloc (db, total + n,
273 IDX_result_data);
274 if (newp != NULL)
276 /* Adjust pointer into the memory block. */
277 cp = (char *) newp + (cp - (char *) dataset);
278 key_copy = (char *) newp + (key_copy - (char *) dataset);
280 dataset = memcpy (newp, dataset, total + n);
281 alloca_used = false;
283 else
284 ++db->head->addfailed;
286 /* Mark the old record as obsolete. */
287 dh->usable = false;
290 else
292 /* We write the dataset before inserting it to the database
293 since while inserting this thread might block and so would
294 unnecessarily let the receiver wait. */
295 assert (fd != -1);
297 #ifdef HAVE_SENDFILE
298 if (__builtin_expect (db->mmap_used, 1) && !alloca_used)
300 assert (db->wr_fd != -1);
301 assert ((char *) &dataset->resp > (char *) db->data);
302 assert ((char *) &dataset->resp - (char *) db->head
303 + total
304 <= (sizeof (struct database_pers_head)
305 + db->head->module * sizeof (ref_t)
306 + db->head->data_size));
307 written = sendfileall (fd, db->wr_fd,
308 (char *) &dataset->resp
309 - (char *) db->head, total);
310 # ifndef __ASSUME_SENDFILE
311 if (written == -1 && errno == ENOSYS)
312 goto use_write;
313 # endif
315 else
316 # ifndef __ASSUME_SENDFILE
317 use_write:
318 # endif
319 #endif
320 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. */
326 if (! alloca_used)
328 /* If necessary, we also propagate the data to disk. */
329 if (db->persistent)
331 // XXX async OK?
332 uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
333 msync ((void *) pval,
334 ((uintptr_t) dataset & pagesize_m1) + total + n,
335 MS_ASYNC);
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
344 added. */
345 bool first = true;
347 /* If the request was by UID, add that entry first. */
348 if (req->type == GETPWBYUID)
350 if (cache_add (GETPWBYUID, cp, key_offset, &dataset->head, true,
351 db, owner, he == NULL) < 0)
352 goto out;
354 first = false;
356 /* If the key is different from the name add a separate entry. */
357 else if (strcmp (key_copy, dataset->strdata) != 0)
359 if (cache_add (GETPWBYNAME, key_copy, key_len + 1,
360 &dataset->head, true, db, owner, he == NULL) < 0)
361 goto out;
363 first = false;
366 /* We have to add the value for both, byname and byuid. */
367 if ((req->type == GETPWBYNAME || db->propagate)
368 && __builtin_expect (cache_add (GETPWBYNAME, dataset->strdata,
369 pw_name_len, &dataset->head,
370 first, db, owner, he == NULL)
371 == 0, 1))
373 if (req->type == GETPWBYNAME && db->propagate)
374 (void) cache_add (GETPWBYUID, cp, key_offset, &dataset->head,
375 false, db, owner, false);
378 out:
379 pthread_rwlock_unlock (&db->lock);
383 if (__builtin_expect (written != total, 0) && debug_level > 0)
385 char buf[256];
386 dbg_log (_("short write in %s: %s"), __FUNCTION__,
387 strerror_r (errno, buf, sizeof (buf)));
392 union keytype
394 void *v;
395 uid_t u;
399 static int
400 lookup (int type, union keytype key, struct passwd *resultbufp, char *buffer,
401 size_t buflen, struct passwd **pwd)
403 if (type == GETPWBYNAME)
404 return __getpwnam_r (key.v, resultbufp, buffer, buflen, pwd);
405 else
406 return __getpwuid_r (key.u, resultbufp, buffer, buflen, pwd);
410 static void
411 addpwbyX (struct database_dyn *db, int fd, request_header *req,
412 union keytype key, const char *keystr, uid_t c_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 passwd resultbuf;
422 struct passwd *pwd;
423 bool use_malloc = false;
424 int errval = 0;
426 if (__builtin_expect (debug_level > 0, 0))
428 if (he == NULL)
429 dbg_log (_("Haven't found \"%s\" in password cache!"), keystr);
430 else
431 dbg_log (_("Reloading \"%s\" in password cache!"), keystr);
434 while (lookup (req->type, key, &resultbuf, buffer, buflen, &pwd) != 0
435 && (errval = errno) == ERANGE)
437 errno = 0;
439 if (__builtin_expect (buflen > 32768, 0))
441 char *old_buffer = buffer;
442 buflen *= 2;
443 buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
444 if (buffer == NULL)
446 /* We ran out of memory. We cannot do anything but
447 sending a negative response. In reality this should
448 never happen. */
449 pwd = NULL;
450 buffer = old_buffer;
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. */
455 errval = EAGAIN;
456 break;
458 use_malloc = true;
460 else
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 /* Add the entry to the cache. */
467 cache_addpw (db, fd, req, keystr, pwd, c_uid, he, dh, errval);
469 if (use_malloc)
470 free (buffer);
474 void
475 addpwbyname (struct database_dyn *db, int fd, request_header *req,
476 void *key, uid_t c_uid)
478 union keytype u = { .v = key };
480 addpwbyX (db, fd, req, u, key, c_uid, NULL, NULL);
484 void
485 readdpwbyname (struct database_dyn *db, struct hashentry *he,
486 struct datahead *dh)
488 request_header req =
490 .type = GETPWBYNAME,
491 .key_len = he->len
493 union keytype u = { .v = db->data + he->key };
495 addpwbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);
499 void
500 addpwbyuid (struct database_dyn *db, int fd, request_header *req,
501 void *key, uid_t c_uid)
503 char *ep;
504 uid_t uid = strtoul ((char *) key, &ep, 10);
506 if (*(char *) key == '\0' || *ep != '\0') /* invalid numeric uid */
508 if (debug_level > 0)
509 dbg_log (_("Invalid numeric uid \"%s\"!"), (char *) key);
511 errno = EINVAL;
512 return;
515 union keytype u = { .u = uid };
517 addpwbyX (db, fd, req, u, key, c_uid, NULL, NULL);
521 void
522 readdpwbyuid (struct database_dyn *db, struct hashentry *he,
523 struct datahead *dh)
525 char *ep;
526 uid_t uid = strtoul (db->data + he->key, &ep, 10);
528 /* Since the key has been added before it must be OK. */
529 assert (*(db->data + he->key) != '\0' && *ep == '\0');
531 request_header req =
533 .type = GETPWBYUID,
534 .key_len = he->len
536 union keytype u = { .u = uid };
538 addpwbyX (db, -1, &req, u, db->data + he->key, he->owner, he, dh);