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. */
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 pw_response_header disabled
=
46 .version
= NSCD_VERSION
,
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
,
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
)
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. */
94 pw_response_header resp
;
98 assert (offsetof (struct dataset
, resp
) == offsetof (struct datahead
, data
));
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;
115 /* We have no data. This means we send the standard reply for this
117 written
= total
= sizeof (notfound
);
120 written
= TEMP_FAILURE_RETRY (send (fd
, ¬found
, total
,
123 dataset
= mempool_alloc (db
, sizeof (struct dataset
) + req
->key_len
,
125 /* If we cannot permanently store the result, so be it. */
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
, ¬found
, 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. */
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 if (cache_add (req
->type
, key_copy
, req
->key_len
,
157 &dataset
->head
, true, db
, owner
) < 0)
158 /* Ensure the data can be recovered. */
159 dataset
->head
.usable
= false;
162 pthread_rwlock_unlock (&db
->lock
);
164 /* Mark the old entry as obsolete. */
169 ++db
->head
->addfailed
;
174 /* Determine the I/O structure. */
175 size_t pw_name_len
= strlen (pwd
->pw_name
) + 1;
176 size_t pw_passwd_len
= strlen (pwd
->pw_passwd
) + 1;
177 size_t pw_gecos_len
= strlen (pwd
->pw_gecos
) + 1;
178 size_t pw_dir_len
= strlen (pwd
->pw_dir
) + 1;
179 size_t pw_shell_len
= strlen (pwd
->pw_shell
) + 1;
181 const size_t key_len
= strlen (key
);
182 const size_t buf_len
= 3 * sizeof (pwd
->pw_uid
) + key_len
+ 1;
183 char *buf
= alloca (buf_len
);
186 /* We need this to insert the `byuid' entry. */
188 n
= snprintf (buf
, buf_len
, "%d%c%n%s", pwd
->pw_uid
, '\0',
189 &key_offset
, (char *) key
) + 1;
191 written
= total
= (sizeof (struct dataset
) + pw_name_len
+ pw_passwd_len
192 + pw_gecos_len
+ pw_dir_len
+ pw_shell_len
);
194 /* If we refill the cache, first assume the reconrd did not
195 change. Allocate memory on the cache since it is likely
196 discarded anyway. If it turns out to be necessary to have a
197 new record we can still allocate real memory. */
198 bool alloca_used
= false;
203 dataset
= (struct dataset
*) mempool_alloc (db
, total
+ n
,
206 ++db
->head
->addfailed
;
211 /* We cannot permanently add the result in the moment. But
212 we can provide the result as is. Store the data in some
214 dataset
= (struct dataset
*) alloca (total
+ n
);
216 /* We cannot add this record to the permanent database. */
220 dataset
->head
.allocsize
= total
+ n
;
221 dataset
->head
.recsize
= total
- offsetof (struct dataset
, resp
);
222 dataset
->head
.notfound
= false;
223 dataset
->head
.nreloads
= he
== NULL
? 0 : (dh
->nreloads
+ 1);
224 dataset
->head
.usable
= true;
226 /* Compute the timeout time. */
227 dataset
->head
.timeout
= t
+ db
->postimeout
;
229 dataset
->resp
.version
= NSCD_VERSION
;
230 dataset
->resp
.found
= 1;
231 dataset
->resp
.pw_name_len
= pw_name_len
;
232 dataset
->resp
.pw_passwd_len
= pw_passwd_len
;
233 dataset
->resp
.pw_uid
= pwd
->pw_uid
;
234 dataset
->resp
.pw_gid
= pwd
->pw_gid
;
235 dataset
->resp
.pw_gecos_len
= pw_gecos_len
;
236 dataset
->resp
.pw_dir_len
= pw_dir_len
;
237 dataset
->resp
.pw_shell_len
= pw_shell_len
;
239 cp
= dataset
->strdata
;
241 /* Copy the strings over into the buffer. */
242 cp
= mempcpy (cp
, pwd
->pw_name
, pw_name_len
);
243 cp
= mempcpy (cp
, pwd
->pw_passwd
, pw_passwd_len
);
244 cp
= mempcpy (cp
, pwd
->pw_gecos
, pw_gecos_len
);
245 cp
= mempcpy (cp
, pwd
->pw_dir
, pw_dir_len
);
246 cp
= mempcpy (cp
, pwd
->pw_shell
, pw_shell_len
);
248 /* Finally the stringified UID value. */
250 char *key_copy
= cp
+ key_offset
;
251 assert (key_copy
== (char *) rawmemchr (cp
, '\0') + 1);
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
,
279 /* Adjust pointer into the memory block. */
280 cp
= (char *) newp
+ (cp
- (char *) dataset
);
281 key_copy
= (char *) newp
+ (key_copy
- (char *) dataset
);
283 dataset
= memcpy (newp
, dataset
, total
+ n
);
287 ++db
->head
->addfailed
;
289 /* Mark the old record as obsolete. */
295 /* We write the dataset before inserting it to the database
296 since while inserting this thread might block and so would
297 unnecessarily let the receiver wait. */
301 if (__builtin_expect (db
->mmap_used
, 1) && !alloca_used
)
303 assert (db
->wr_fd
!= -1);
304 assert ((char *) &dataset
->resp
> (char *) db
->data
);
305 assert ((char *) &dataset
->resp
- (char *) db
->head
307 <= (sizeof (struct database_pers_head
)
308 + db
->head
->module
* sizeof (ref_t
)
309 + db
->head
->data_size
));
310 written
= sendfileall (fd
, db
->wr_fd
,
311 (char *) &dataset
->resp
312 - (char *) db
->head
, total
);
313 # ifndef __ASSUME_SENDFILE
314 if (written
== -1 && errno
== ENOSYS
)
319 # ifndef __ASSUME_SENDFILE
323 written
= writeall (fd
, &dataset
->resp
, total
);
327 /* Add the record to the database. But only if it has not been
328 stored on the stack. */
331 /* If necessary, we also propagate the data to disk. */
335 uintptr_t pval
= (uintptr_t) dataset
& ~pagesize_m1
;
336 msync ((void *) pval
,
337 ((uintptr_t) dataset
& pagesize_m1
) + total
+ n
,
341 /* Now get the lock to safely insert the records. */
342 pthread_rwlock_rdlock (&db
->lock
);
344 /* NB: in the following code we always must add the entry
345 marked with FIRST first. Otherwise we end up with
346 dangling "pointers" in case a latter hash entry cannot be
350 /* If the request was by UID, add that entry first. */
351 if (req
->type
== GETPWBYUID
)
353 if (cache_add (GETPWBYUID
, cp
, key_offset
, &dataset
->head
, true,
356 /* Could not allocate memory. Make sure the data gets
358 dataset
->head
.usable
= false;
364 /* If the key is different from the name add a separate entry. */
365 else if (strcmp (key_copy
, dataset
->strdata
) != 0)
367 if (cache_add (GETPWBYNAME
, key_copy
, key_len
+ 1,
368 &dataset
->head
, true, db
, owner
) < 0)
370 /* Could not allocate memory. Make sure the data gets
372 dataset
->head
.usable
= false;
379 /* We have to add the value for both, byname and byuid. */
380 if ((req
->type
== GETPWBYNAME
|| db
->propagate
)
381 && __builtin_expect (cache_add (GETPWBYNAME
, dataset
->strdata
,
382 pw_name_len
, &dataset
->head
,
383 first
, db
, owner
) == 0, 1))
385 if (req
->type
== GETPWBYNAME
&& db
->propagate
)
386 (void) cache_add (GETPWBYUID
, cp
, key_offset
, &dataset
->head
,
387 req
->type
!= GETPWBYNAME
, db
, owner
);
390 /* Could not allocate memory. Make sure the data gets
392 dataset
->head
.usable
= false;
395 pthread_rwlock_unlock (&db
->lock
);
399 if (__builtin_expect (written
!= total
, 0) && debug_level
> 0)
402 dbg_log (_("short write in %s: %s"), __FUNCTION__
,
403 strerror_r (errno
, buf
, sizeof (buf
)));
416 lookup (int type
, union keytype key
, struct passwd
*resultbufp
, char *buffer
,
417 size_t buflen
, struct passwd
**pwd
)
419 if (type
== GETPWBYNAME
)
420 return __getpwnam_r (key
.v
, resultbufp
, buffer
, buflen
, pwd
);
422 return __getpwuid_r (key
.u
, resultbufp
, buffer
, buflen
, pwd
);
427 addpwbyX (struct database_dyn
*db
, int fd
, request_header
*req
,
428 union keytype key
, const char *keystr
, uid_t c_uid
,
429 struct hashentry
*he
, struct datahead
*dh
)
431 /* Search for the entry matching the key. Please note that we don't
432 look again in the table whether the dataset is now available. We
433 simply insert it. It does not matter if it is in there twice. The
434 pruning function only will look at the timestamp. */
435 size_t buflen
= 1024;
436 char *buffer
= (char *) alloca (buflen
);
437 struct passwd resultbuf
;
439 bool use_malloc
= false;
442 if (__builtin_expect (debug_level
> 0, 0))
445 dbg_log (_("Haven't found \"%s\" in password cache!"), keystr
);
447 dbg_log (_("Reloading \"%s\" in password cache!"), keystr
);
450 while (lookup (req
->type
, key
, &resultbuf
, buffer
, buflen
, &pwd
) != 0
451 && (errval
= errno
) == ERANGE
)
455 if (__builtin_expect (buflen
> 32768, 0))
457 char *old_buffer
= buffer
;
459 buffer
= (char *) realloc (use_malloc
? buffer
: NULL
, buflen
);
462 /* We ran out of memory. We cannot do anything but
463 sending a negative response. In reality this should
468 /* We set the error to indicate this is (possibly) a
469 temporary error and that it does not mean the entry
470 is not available at all. */
477 /* Allocate a new buffer on the stack. If possible combine it
478 with the previously allocated buffer. */
479 buffer
= (char *) extend_alloca (buffer
, buflen
, 2 * buflen
);
482 /* Add the entry to the cache. */
483 cache_addpw (db
, fd
, req
, keystr
, pwd
, c_uid
, he
, dh
, errval
);
491 addpwbyname (struct database_dyn
*db
, int fd
, request_header
*req
,
492 void *key
, uid_t c_uid
)
494 union keytype u
= { .v
= key
};
496 addpwbyX (db
, fd
, req
, u
, key
, c_uid
, NULL
, NULL
);
501 readdpwbyname (struct database_dyn
*db
, struct hashentry
*he
,
509 union keytype u
= { .v
= db
->data
+ he
->key
};
511 addpwbyX (db
, -1, &req
, u
, db
->data
+ he
->key
, he
->owner
, he
, dh
);
516 addpwbyuid (struct database_dyn
*db
, int fd
, request_header
*req
,
517 void *key
, uid_t c_uid
)
520 uid_t uid
= strtoul ((char *) key
, &ep
, 10);
522 if (*(char *) key
== '\0' || *ep
!= '\0') /* invalid numeric uid */
525 dbg_log (_("Invalid numeric uid \"%s\"!"), (char *) key
);
531 union keytype u
= { .u
= uid
};
533 addpwbyX (db
, fd
, req
, u
, key
, c_uid
, NULL
, NULL
);
538 readdpwbyuid (struct database_dyn
*db
, struct hashentry
*he
,
542 uid_t uid
= strtoul (db
->data
+ he
->key
, &ep
, 10);
544 /* Since the key has been added before it must be OK. */
545 assert (*(db
->data
+ he
->key
) != '\0' && *ep
== '\0');
552 union keytype u
= { .u
= uid
};
554 addpwbyX (db
, -1, &req
, u
, db
->data
+ he
->key
, he
->owner
, he
, dh
);