1 /* Cache handling for passwd lookup.
2 Copyright (C) 1998-2008, 2009, 2011 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
*const 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
));
100 time_t timeout
= MAX_TIMEOUT_VALUE
;
103 if (he
!= NULL
&& errval
== EAGAIN
)
105 /* If we have an old record available but cannot find one
106 now because the service is not available we keep the old
107 record and make sure it does not get removed. */
108 if (reload_count
!= UINT_MAX
&& dh
->nreloads
== reload_count
)
109 /* Do not reset the value if we never not reload the record. */
110 dh
->nreloads
= reload_count
- 1;
112 /* Reload with the same time-to-live value. */
113 timeout
= dh
->timeout
= t
+ db
->postimeout
;
119 /* We have no data. This means we send the standard reply for this
121 written
= total
= sizeof (notfound
);
124 written
= TEMP_FAILURE_RETRY (send (fd
, ¬found
, total
,
127 dataset
= mempool_alloc (db
, sizeof (struct dataset
) + req
->key_len
,
129 /* If we cannot permanently store the result, so be it. */
132 dataset
->head
.allocsize
= sizeof (struct dataset
) + req
->key_len
;
133 dataset
->head
.recsize
= total
;
134 dataset
->head
.notfound
= true;
135 dataset
->head
.nreloads
= 0;
136 dataset
->head
.usable
= true;
138 /* Compute the timeout time. */
139 timeout
= dataset
->head
.timeout
= t
+ db
->negtimeout
;
141 /* This is the reply. */
142 memcpy (&dataset
->resp
, ¬found
, total
);
144 /* Copy the key data. */
145 char *key_copy
= memcpy (dataset
->strdata
, key
, req
->key_len
);
147 /* If necessary, we also propagate the data to disk. */
151 uintptr_t pval
= (uintptr_t) dataset
& ~pagesize_m1
;
152 msync ((void *) pval
,
153 ((uintptr_t) dataset
& pagesize_m1
)
154 + sizeof (struct dataset
) + req
->key_len
, MS_ASYNC
);
157 (void) cache_add (req
->type
, key_copy
, req
->key_len
,
158 &dataset
->head
, true, db
, owner
, he
== NULL
);
160 pthread_rwlock_unlock (&db
->lock
);
162 /* Mark the old entry as obsolete. */
170 /* Determine the I/O structure. */
171 size_t pw_name_len
= strlen (pwd
->pw_name
) + 1;
172 size_t pw_passwd_len
= strlen (pwd
->pw_passwd
) + 1;
173 size_t pw_gecos_len
= strlen (pwd
->pw_gecos
) + 1;
174 size_t pw_dir_len
= strlen (pwd
->pw_dir
) + 1;
175 size_t pw_shell_len
= strlen (pwd
->pw_shell
) + 1;
177 const size_t key_len
= strlen (key
);
178 const size_t buf_len
= 3 * sizeof (pwd
->pw_uid
) + key_len
+ 1;
179 char *buf
= alloca (buf_len
);
182 /* We need this to insert the `byuid' entry. */
184 n
= snprintf (buf
, buf_len
, "%d%c%n%s", pwd
->pw_uid
, '\0',
185 &key_offset
, (char *) key
) + 1;
187 written
= total
= (offsetof (struct dataset
, strdata
)
188 + 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;
199 dataset
= (struct dataset
*) mempool_alloc (db
, total
+ n
, 1);
203 /* We cannot permanently add the result in the moment. But
204 we can provide the result as is. Store the data in some
206 dataset
= (struct dataset
*) alloca (total
+ n
);
208 /* We cannot add this record to the permanent database. */
212 dataset
->head
.allocsize
= total
+ n
;
213 dataset
->head
.recsize
= total
- offsetof (struct dataset
, resp
);
214 dataset
->head
.notfound
= false;
215 dataset
->head
.nreloads
= he
== NULL
? 0 : (dh
->nreloads
+ 1);
216 dataset
->head
.usable
= true;
218 /* Compute the timeout time. */
219 timeout
= dataset
->head
.timeout
= t
+ db
->postimeout
;
221 dataset
->resp
.version
= NSCD_VERSION
;
222 dataset
->resp
.found
= 1;
223 dataset
->resp
.pw_name_len
= pw_name_len
;
224 dataset
->resp
.pw_passwd_len
= pw_passwd_len
;
225 dataset
->resp
.pw_uid
= pwd
->pw_uid
;
226 dataset
->resp
.pw_gid
= pwd
->pw_gid
;
227 dataset
->resp
.pw_gecos_len
= pw_gecos_len
;
228 dataset
->resp
.pw_dir_len
= pw_dir_len
;
229 dataset
->resp
.pw_shell_len
= pw_shell_len
;
231 cp
= dataset
->strdata
;
233 /* Copy the strings over into the buffer. */
234 cp
= mempcpy (cp
, pwd
->pw_name
, pw_name_len
);
235 cp
= mempcpy (cp
, pwd
->pw_passwd
, pw_passwd_len
);
236 cp
= mempcpy (cp
, pwd
->pw_gecos
, pw_gecos_len
);
237 cp
= mempcpy (cp
, pwd
->pw_dir
, pw_dir_len
);
238 cp
= mempcpy (cp
, pwd
->pw_shell
, pw_shell_len
);
240 /* Finally the stringified UID 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 (dataset
->head
.allocsize
== dh
->allocsize
255 && dataset
->head
.recsize
== 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 pointer into the memory block. */
274 cp
= (char *) newp
+ (cp
- (char *) dataset
);
275 key_copy
= (char *) newp
+ (key_copy
- (char *) dataset
);
277 dataset
= memcpy (newp
, dataset
, total
+ n
);
281 /* Mark the old record as obsolete. */
287 /* We write the dataset before inserting it to the database
288 since while inserting this thread might block and so would
289 unnecessarily let the receiver wait. */
293 if (__builtin_expect (db
->mmap_used
, 1) && !alloca_used
)
295 assert (db
->wr_fd
!= -1);
296 assert ((char *) &dataset
->resp
> (char *) db
->data
);
297 assert ((char *) dataset
- (char *) db
->head
299 <= (sizeof (struct database_pers_head
)
300 + db
->head
->module
* sizeof (ref_t
)
301 + db
->head
->data_size
));
302 written
= sendfileall (fd
, db
->wr_fd
,
303 (char *) &dataset
->resp
304 - (char *) db
->head
, dataset
->head
.recsize
);
305 # ifndef __ASSUME_SENDFILE
306 if (written
== -1 && errno
== ENOSYS
)
311 # ifndef __ASSUME_SENDFILE
315 written
= writeall (fd
, &dataset
->resp
, dataset
->head
.recsize
);
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 UID, add that entry first. */
340 if (req
->type
== GETPWBYUID
)
342 if (cache_add (GETPWBYUID
, 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
, dataset
->strdata
) != 0)
351 if (cache_add (GETPWBYNAME
, 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
== GETPWBYNAME
|| db
->propagate
)
360 && __builtin_expect (cache_add (GETPWBYNAME
, dataset
->strdata
,
361 pw_name_len
, &dataset
->head
,
362 first
, db
, owner
, he
== NULL
)
365 if (req
->type
== GETPWBYNAME
&& db
->propagate
)
366 (void) cache_add (GETPWBYUID
, cp
, key_offset
, &dataset
->head
,
367 false, db
, owner
, false);
371 pthread_rwlock_unlock (&db
->lock
);
375 if (__builtin_expect (written
!= total
, 0) && debug_level
> 0)
378 dbg_log (_("short write in %s: %s"), __FUNCTION__
,
379 strerror_r (errno
, buf
, sizeof (buf
)));
394 lookup (int type
, union keytype key
, struct passwd
*resultbufp
, char *buffer
,
395 size_t buflen
, struct passwd
**pwd
)
397 if (type
== GETPWBYNAME
)
398 return __getpwnam_r (key
.v
, resultbufp
, buffer
, buflen
, pwd
);
400 return __getpwuid_r (key
.u
, resultbufp
, buffer
, buflen
, pwd
);
405 addpwbyX (struct database_dyn
*db
, int fd
, request_header
*req
,
406 union keytype key
, const char *keystr
, uid_t c_uid
,
407 struct hashentry
*he
, struct datahead
*dh
)
409 /* Search for the entry matching the key. Please note that we don't
410 look again in the table whether the dataset is now available. We
411 simply insert it. It does not matter if it is in there twice. The
412 pruning function only will look at the timestamp. */
413 size_t buflen
= 1024;
414 char *buffer
= (char *) alloca (buflen
);
415 struct passwd resultbuf
;
417 bool use_malloc
= false;
420 if (__builtin_expect (debug_level
> 0, 0))
423 dbg_log (_("Haven't found \"%s\" in password cache!"), keystr
);
425 dbg_log (_("Reloading \"%s\" in password cache!"), keystr
);
428 while (lookup (req
->type
, key
, &resultbuf
, buffer
, buflen
, &pwd
) != 0
429 && (errval
= errno
) == ERANGE
)
433 if (__builtin_expect (buflen
> 32768, 0))
435 char *old_buffer
= buffer
;
437 buffer
= (char *) realloc (use_malloc
? buffer
: NULL
, buflen
);
440 /* We ran out of memory. We cannot do anything but
441 sending a negative response. In reality this should
446 /* We set the error to indicate this is (possibly) a
447 temporary error and that it does not mean the entry
448 is not available at all. */
455 /* Allocate a new buffer on the stack. If possible combine it
456 with the previously allocated buffer. */
457 buffer
= (char *) extend_alloca (buffer
, buflen
, 2 * buflen
);
460 /* Add the entry to the cache. */
461 time_t timeout
= cache_addpw (db
, fd
, req
, keystr
, pwd
, c_uid
, he
, dh
,
472 addpwbyname (struct database_dyn
*db
, int fd
, request_header
*req
,
473 void *key
, uid_t c_uid
)
475 union keytype u
= { .v
= key
};
477 addpwbyX (db
, fd
, req
, u
, key
, c_uid
, NULL
, NULL
);
482 readdpwbyname (struct database_dyn
*db
, struct hashentry
*he
,
490 union keytype u
= { .v
= db
->data
+ he
->key
};
492 return addpwbyX (db
, -1, &req
, u
, db
->data
+ he
->key
, he
->owner
, he
, dh
);
497 addpwbyuid (struct database_dyn
*db
, int fd
, request_header
*req
,
498 void *key
, uid_t c_uid
)
501 uid_t uid
= strtoul ((char *) key
, &ep
, 10);
503 if (*(char *) key
== '\0' || *ep
!= '\0') /* invalid numeric uid */
506 dbg_log (_("Invalid numeric uid \"%s\"!"), (char *) key
);
512 union keytype u
= { .u
= uid
};
514 addpwbyX (db
, fd
, req
, u
, key
, c_uid
, NULL
, NULL
);
519 readdpwbyuid (struct database_dyn
*db
, struct hashentry
*he
,
523 uid_t uid
= strtoul (db
->data
+ he
->key
, &ep
, 10);
525 /* Since the key has been added before it must be OK. */
526 assert (*(db
->data
+ he
->key
) != '\0' && *ep
== '\0');
533 union keytype u
= { .u
= uid
};
535 return addpwbyX (db
, -1, &req
, u
, db
->data
+ he
->key
, he
->owner
, he
, dh
);