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f7e7a396 | 1 | /* Cache handling for host lookup. |
bfff8b1b | 2 | Copyright (C) 2004-2017 Free Software Foundation, Inc. |
f7e7a396 UD |
3 | This file is part of the GNU C Library. |
4 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2004. | |
5 | ||
43bc8ac6 | 6 | This program is free software; you can redistribute it and/or modify |
2e2efe65 RM |
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. | |
f7e7a396 | 10 | |
43bc8ac6 | 11 | This program is distributed in the hope that it will be useful, |
f7e7a396 | 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
43bc8ac6 UD |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | GNU General Public License for more details. | |
f7e7a396 | 15 | |
43bc8ac6 | 16 | You should have received a copy of the GNU General Public License |
59ba27a6 | 17 | along with this program; if not, see <http://www.gnu.org/licenses/>. */ |
f7e7a396 UD |
18 | |
19 | #include <assert.h> | |
20 | #include <errno.h> | |
21 | #include <grp.h> | |
22 | #include <libintl.h> | |
23 | #include <string.h> | |
24 | #include <time.h> | |
25 | #include <unistd.h> | |
26 | #include <sys/mman.h> | |
866ba63b | 27 | #include <scratch_buffer.h> |
eac10791 UD |
28 | |
29 | #include "dbg_log.h" | |
30 | #include "nscd.h" | |
31 | #ifdef HAVE_SENDFILE | |
32 | # include <kernel-features.h> | |
33 | #endif | |
f7e7a396 UD |
34 | |
35 | #include "../nss/nsswitch.h" | |
36 | ||
37 | ||
38 | /* Type of the lookup function. */ | |
39 | typedef enum nss_status (*initgroups_dyn_function) (const char *, gid_t, | |
40 | long int *, long int *, | |
41 | gid_t **, long int, int *); | |
42 | ||
43 | ||
44 | static const initgr_response_header notfound = | |
45 | { | |
46 | .version = NSCD_VERSION, | |
47 | .found = 0, | |
48 | .ngrps = 0 | |
49 | }; | |
50 | ||
51 | ||
52 | #include "../grp/compat-initgroups.c" | |
53 | ||
54 | ||
a4c7ea7b | 55 | static time_t |
f7e7a396 | 56 | addinitgroupsX (struct database_dyn *db, int fd, request_header *req, |
20e498bd | 57 | void *key, uid_t uid, struct hashentry *const he, |
f7e7a396 UD |
58 | struct datahead *dh) |
59 | { | |
60 | /* Search for the entry matching the key. Please note that we don't | |
61 | look again in the table whether the dataset is now available. We | |
62 | simply insert it. It does not matter if it is in there twice. The | |
63 | pruning function only will look at the timestamp. */ | |
64 | ||
65 | ||
66 | /* We allocate all data in one memory block: the iov vector, | |
67 | the response header and the dataset itself. */ | |
68 | struct dataset | |
69 | { | |
70 | struct datahead head; | |
71 | initgr_response_header resp; | |
72 | char strdata[0]; | |
73 | } *dataset = NULL; | |
74 | ||
a1ffb40e | 75 | if (__glibc_unlikely (debug_level > 0)) |
f7e7a396 UD |
76 | { |
77 | if (he == NULL) | |
78 | dbg_log (_("Haven't found \"%s\" in group cache!"), (char *) key); | |
79 | else | |
80 | dbg_log (_("Reloading \"%s\" in group cache!"), (char *) key); | |
81 | } | |
82 | ||
83 | static service_user *group_database; | |
b2179107 | 84 | service_user *nip; |
f7e7a396 UD |
85 | int no_more; |
86 | ||
b2179107 | 87 | if (group_database == NULL) |
f7e7a396 | 88 | no_more = __nss_database_lookup ("group", NULL, |
b2179107 AS |
89 | "compat [NOTFOUND=return] files", |
90 | &group_database); | |
91 | else | |
92 | no_more = 0; | |
93 | nip = group_database; | |
f7e7a396 UD |
94 | |
95 | /* We always use sysconf even if NGROUPS_MAX is defined. That way, the | |
96 | limit can be raised in the kernel configuration without having to | |
97 | recompile libc. */ | |
98 | long int limit = __sysconf (_SC_NGROUPS_MAX); | |
99 | ||
100 | long int size; | |
101 | if (limit > 0) | |
102 | /* We limit the size of the intially allocated array. */ | |
103 | size = MIN (limit, 64); | |
104 | else | |
105 | /* No fixed limit on groups. Pick a starting buffer size. */ | |
106 | size = 16; | |
107 | ||
108 | long int start = 0; | |
109 | bool all_tryagain = true; | |
cd248c3f | 110 | bool any_success = false; |
f7e7a396 | 111 | |
e8667ddc | 112 | /* This is temporary memory, we need not (and must not) call |
f7e7a396 UD |
113 | mempool_alloc. */ |
114 | // XXX This really should use alloca. need to change the backends. | |
115 | gid_t *groups = (gid_t *) malloc (size * sizeof (gid_t)); | |
a1ffb40e | 116 | if (__glibc_unlikely (groups == NULL)) |
f7e7a396 UD |
117 | /* No more memory. */ |
118 | goto out; | |
119 | ||
120 | /* Nothing added yet. */ | |
121 | while (! no_more) | |
122 | { | |
695c4370 | 123 | long int prev_start = start; |
f7e7a396 UD |
124 | enum nss_status status; |
125 | initgroups_dyn_function fct; | |
126 | fct = __nss_lookup_function (nip, "initgroups_dyn"); | |
127 | ||
128 | if (fct == NULL) | |
129 | { | |
130 | status = compat_call (nip, key, -1, &start, &size, &groups, | |
131 | limit, &errno); | |
132 | ||
133 | if (nss_next_action (nip, NSS_STATUS_UNAVAIL) != NSS_ACTION_CONTINUE) | |
134 | break; | |
135 | } | |
136 | else | |
137 | status = DL_CALL_FCT (fct, (key, -1, &start, &size, &groups, | |
138 | limit, &errno)); | |
139 | ||
695c4370 UD |
140 | /* Remove duplicates. */ |
141 | long int cnt = prev_start; | |
142 | while (cnt < start) | |
143 | { | |
144 | long int inner; | |
145 | for (inner = 0; inner < prev_start; ++inner) | |
146 | if (groups[inner] == groups[cnt]) | |
147 | break; | |
148 | ||
149 | if (inner < prev_start) | |
150 | groups[cnt] = groups[--start]; | |
151 | else | |
152 | ++cnt; | |
153 | } | |
154 | ||
f7e7a396 UD |
155 | if (status != NSS_STATUS_TRYAGAIN) |
156 | all_tryagain = false; | |
157 | ||
158 | /* This is really only for debugging. */ | |
159 | if (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_RETURN) | |
160 | __libc_fatal ("illegal status in internal_getgrouplist"); | |
161 | ||
fbbc73b3 UD |
162 | any_success |= status == NSS_STATUS_SUCCESS; |
163 | ||
f7e7a396 UD |
164 | if (status != NSS_STATUS_SUCCESS |
165 | && nss_next_action (nip, status) == NSS_ACTION_RETURN) | |
166 | break; | |
167 | ||
168 | if (nip->next == NULL) | |
169 | no_more = -1; | |
170 | else | |
171 | nip = nip->next; | |
172 | } | |
173 | ||
306dfba9 | 174 | bool all_written; |
f7e7a396 | 175 | ssize_t total; |
a4c7ea7b | 176 | time_t timeout; |
f7e7a396 | 177 | out: |
306dfba9 | 178 | all_written = true; |
a4c7ea7b | 179 | timeout = MAX_TIMEOUT_VALUE; |
fbbc73b3 | 180 | if (!any_success) |
f7e7a396 UD |
181 | { |
182 | /* Nothing found. Create a negative result record. */ | |
306dfba9 | 183 | total = sizeof (notfound); |
f7e7a396 UD |
184 | |
185 | if (he != NULL && all_tryagain) | |
186 | { | |
187 | /* If we have an old record available but cannot find one now | |
188 | because the service is not available we keep the old record | |
189 | and make sure it does not get removed. */ | |
190 | if (reload_count != UINT_MAX && dh->nreloads == reload_count) | |
191 | /* Do not reset the value if we never not reload the record. */ | |
192 | dh->nreloads = reload_count - 1; | |
a4c7ea7b UD |
193 | |
194 | /* Reload with the same time-to-live value. */ | |
195 | timeout = dh->timeout = time (NULL) + db->postimeout; | |
f7e7a396 UD |
196 | } |
197 | else | |
198 | { | |
199 | /* We have no data. This means we send the standard reply for this | |
200 | case. */ | |
306dfba9 AS |
201 | if (fd != -1 |
202 | && TEMP_FAILURE_RETRY (send (fd, ¬found, total, | |
203 | MSG_NOSIGNAL)) != total) | |
204 | all_written = false; | |
f7e7a396 | 205 | |
3e1aa84e UD |
206 | /* If we have a transient error or cannot permanently store |
207 | the result, so be it. */ | |
208 | if (all_tryagain || __builtin_expect (db->negtimeout == 0, 0)) | |
445b4a53 TK |
209 | { |
210 | /* Mark the old entry as obsolete. */ | |
211 | if (dh != NULL) | |
212 | dh->usable = false; | |
213 | } | |
99231d9a UD |
214 | else if ((dataset = mempool_alloc (db, (sizeof (struct dataset) |
215 | + req->key_len), 1)) != NULL) | |
f7e7a396 | 216 | { |
1cdeb237 SP |
217 | timeout = datahead_init_neg (&dataset->head, |
218 | (sizeof (struct dataset) | |
219 | + req->key_len), total, | |
220 | db->negtimeout); | |
f7e7a396 UD |
221 | |
222 | /* This is the reply. */ | |
223 | memcpy (&dataset->resp, ¬found, total); | |
224 | ||
225 | /* Copy the key data. */ | |
226 | char *key_copy = memcpy (dataset->strdata, key, req->key_len); | |
227 | ||
228 | /* If necessary, we also propagate the data to disk. */ | |
229 | if (db->persistent) | |
230 | { | |
231 | // XXX async OK? | |
232 | uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1; | |
233 | msync ((void *) pval, | |
234 | ((uintptr_t) dataset & pagesize_m1) | |
235 | + sizeof (struct dataset) + req->key_len, MS_ASYNC); | |
236 | } | |
237 | ||
7e71e55f | 238 | (void) cache_add (req->type, key_copy, req->key_len, |
528741cb | 239 | &dataset->head, true, db, uid, he == NULL); |
f7e7a396 | 240 | |
00ebd7ed UD |
241 | pthread_rwlock_unlock (&db->lock); |
242 | ||
f7e7a396 UD |
243 | /* Mark the old entry as obsolete. */ |
244 | if (dh != NULL) | |
245 | dh->usable = false; | |
246 | } | |
f7e7a396 UD |
247 | } |
248 | } | |
249 | else | |
250 | { | |
251 | ||
306dfba9 | 252 | total = offsetof (struct dataset, strdata) + start * sizeof (int32_t); |
f7e7a396 UD |
253 | |
254 | /* If we refill the cache, first assume the reconrd did not | |
255 | change. Allocate memory on the cache since it is likely | |
256 | discarded anyway. If it turns out to be necessary to have a | |
257 | new record we can still allocate real memory. */ | |
258 | bool alloca_used = false; | |
259 | dataset = NULL; | |
260 | ||
261 | if (he == NULL) | |
20e498bd UD |
262 | dataset = (struct dataset *) mempool_alloc (db, total + req->key_len, |
263 | 1); | |
f7e7a396 UD |
264 | |
265 | if (dataset == NULL) | |
266 | { | |
267 | /* We cannot permanently add the result in the moment. But | |
268 | we can provide the result as is. Store the data in some | |
269 | temporary memory. */ | |
270 | dataset = (struct dataset *) alloca (total + req->key_len); | |
271 | ||
272 | /* We cannot add this record to the permanent database. */ | |
273 | alloca_used = true; | |
274 | } | |
275 | ||
1cdeb237 SP |
276 | timeout = datahead_init_pos (&dataset->head, total + req->key_len, |
277 | total - offsetof (struct dataset, resp), | |
278 | he == NULL ? 0 : dh->nreloads + 1, | |
279 | db->postimeout); | |
f7e7a396 UD |
280 | |
281 | dataset->resp.version = NSCD_VERSION; | |
282 | dataset->resp.found = 1; | |
283 | dataset->resp.ngrps = start; | |
284 | ||
285 | char *cp = dataset->strdata; | |
286 | ||
287 | /* Copy the GID values. If the size of the types match this is | |
288 | very simple. */ | |
289 | if (sizeof (gid_t) == sizeof (int32_t)) | |
290 | cp = mempcpy (cp, groups, start * sizeof (gid_t)); | |
291 | else | |
292 | { | |
293 | gid_t *gcp = (gid_t *) cp; | |
294 | ||
295 | for (int i = 0; i < start; ++i) | |
296 | *gcp++ = groups[i]; | |
297 | ||
298 | cp = (char *) gcp; | |
299 | } | |
300 | ||
301 | /* Finally the user name. */ | |
302 | memcpy (cp, key, req->key_len); | |
303 | ||
5a337776 UD |
304 | assert (cp == dataset->strdata + total - offsetof (struct dataset, |
305 | strdata)); | |
306 | ||
f7e7a396 UD |
307 | /* Now we can determine whether on refill we have to create a new |
308 | record or not. */ | |
309 | if (he != NULL) | |
310 | { | |
311 | assert (fd == -1); | |
312 | ||
313 | if (total + req->key_len == dh->allocsize | |
314 | && total - offsetof (struct dataset, resp) == dh->recsize | |
315 | && memcmp (&dataset->resp, dh->data, | |
316 | dh->allocsize - offsetof (struct dataset, resp)) == 0) | |
317 | { | |
318 | /* The data has not changed. We will just bump the | |
319 | timeout value. Note that the new record has been | |
320 | allocated on the stack and need not be freed. */ | |
321 | dh->timeout = dataset->head.timeout; | |
322 | ++dh->nreloads; | |
323 | } | |
324 | else | |
325 | { | |
326 | /* We have to create a new record. Just allocate | |
327 | appropriate memory and copy it. */ | |
328 | struct dataset *newp | |
c52137d3 | 329 | = (struct dataset *) mempool_alloc (db, total + req->key_len, |
20e498bd | 330 | 1); |
f7e7a396 UD |
331 | if (newp != NULL) |
332 | { | |
333 | /* Adjust pointer into the memory block. */ | |
334 | cp = (char *) newp + (cp - (char *) dataset); | |
335 | ||
336 | dataset = memcpy (newp, dataset, total + req->key_len); | |
337 | alloca_used = false; | |
338 | } | |
339 | ||
340 | /* Mark the old record as obsolete. */ | |
341 | dh->usable = false; | |
342 | } | |
343 | } | |
344 | else | |
345 | { | |
346 | /* We write the dataset before inserting it to the database | |
347 | since while inserting this thread might block and so would | |
348 | unnecessarily let the receiver wait. */ | |
349 | assert (fd != -1); | |
350 | ||
eac10791 | 351 | #ifdef HAVE_SENDFILE |
74158740 | 352 | if (__builtin_expect (db->mmap_used, 1) && !alloca_used) |
eac10791 UD |
353 | { |
354 | assert (db->wr_fd != -1); | |
355 | assert ((char *) &dataset->resp > (char *) db->data); | |
ea547a1a | 356 | assert ((char *) dataset - (char *) db->head |
eac10791 UD |
357 | + total |
358 | <= (sizeof (struct database_pers_head) | |
359 | + db->head->module * sizeof (ref_t) | |
360 | + db->head->data_size)); | |
306dfba9 AS |
361 | ssize_t written = sendfileall (fd, db->wr_fd, |
362 | (char *) &dataset->resp | |
363 | - (char *) db->head, | |
364 | dataset->head.recsize); | |
365 | if (written != dataset->head.recsize) | |
366 | { | |
eac10791 | 367 | # ifndef __ASSUME_SENDFILE |
306dfba9 AS |
368 | if (written == -1 && errno == ENOSYS) |
369 | goto use_write; | |
eac10791 | 370 | # endif |
306dfba9 AS |
371 | all_written = false; |
372 | } | |
eac10791 UD |
373 | } |
374 | else | |
375 | # ifndef __ASSUME_SENDFILE | |
376 | use_write: | |
377 | # endif | |
378 | #endif | |
306dfba9 AS |
379 | if (writeall (fd, &dataset->resp, dataset->head.recsize) |
380 | != dataset->head.recsize) | |
381 | all_written = false; | |
f7e7a396 UD |
382 | } |
383 | ||
384 | ||
385 | /* Add the record to the database. But only if it has not been | |
386 | stored on the stack. */ | |
387 | if (! alloca_used) | |
388 | { | |
389 | /* If necessary, we also propagate the data to disk. */ | |
390 | if (db->persistent) | |
391 | { | |
392 | // XXX async OK? | |
393 | uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1; | |
394 | msync ((void *) pval, | |
395 | ((uintptr_t) dataset & pagesize_m1) + total + | |
396 | req->key_len, MS_ASYNC); | |
397 | } | |
398 | ||
7e71e55f | 399 | (void) cache_add (INITGROUPS, cp, req->key_len, &dataset->head, true, |
528741cb | 400 | db, uid, he == NULL); |
00ebd7ed UD |
401 | |
402 | pthread_rwlock_unlock (&db->lock); | |
f7e7a396 UD |
403 | } |
404 | } | |
405 | ||
406 | free (groups); | |
407 | ||
306dfba9 | 408 | if (__builtin_expect (!all_written, 0) && debug_level > 0) |
f7e7a396 UD |
409 | { |
410 | char buf[256]; | |
411 | dbg_log (_("short write in %s: %s"), __FUNCTION__, | |
412 | strerror_r (errno, buf, sizeof (buf))); | |
413 | } | |
a4c7ea7b UD |
414 | |
415 | return timeout; | |
f7e7a396 UD |
416 | } |
417 | ||
418 | ||
419 | void | |
420 | addinitgroups (struct database_dyn *db, int fd, request_header *req, void *key, | |
421 | uid_t uid) | |
422 | { | |
423 | addinitgroupsX (db, fd, req, key, uid, NULL, NULL); | |
424 | } | |
425 | ||
426 | ||
a4c7ea7b | 427 | time_t |
f7e7a396 UD |
428 | readdinitgroups (struct database_dyn *db, struct hashentry *he, |
429 | struct datahead *dh) | |
430 | { | |
431 | request_header req = | |
432 | { | |
433 | .type = INITGROUPS, | |
434 | .key_len = he->len | |
435 | }; | |
436 | ||
a4c7ea7b | 437 | return addinitgroupsX (db, -1, &req, db->data + he->key, he->owner, he, dh); |
f7e7a396 | 438 | } |