| /* Cache handling for host lookup. |
| Copyright (C) 2004-2016 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Ulrich Drepper <drepper@redhat.com>, 2004. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published |
| by the Free Software Foundation; version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include <assert.h> |
| #include <errno.h> |
| #include <grp.h> |
| #include <libintl.h> |
| #include <string.h> |
| #include <time.h> |
| #include <unistd.h> |
| #include <sys/mman.h> |
| #include <scratch_buffer.h> |
| |
| #include "dbg_log.h" |
| #include "nscd.h" |
| #ifdef HAVE_SENDFILE |
| # include <kernel-features.h> |
| #endif |
| |
| #include "../nss/nsswitch.h" |
| |
| |
| /* Type of the lookup function. */ |
| typedef enum nss_status (*initgroups_dyn_function) (const char *, gid_t, |
| long int *, long int *, |
| gid_t **, long int, int *); |
| |
| |
| static const initgr_response_header notfound = |
| { |
| .version = NSCD_VERSION, |
| .found = 0, |
| .ngrps = 0 |
| }; |
| |
| |
| #include "../grp/compat-initgroups.c" |
| |
| |
| static time_t |
| addinitgroupsX (struct database_dyn *db, int fd, request_header *req, |
| void *key, uid_t uid, struct hashentry *const he, |
| struct datahead *dh) |
| { |
| /* Search for the entry matching the key. Please note that we don't |
| look again in the table whether the dataset is now available. We |
| simply insert it. It does not matter if it is in there twice. The |
| pruning function only will look at the timestamp. */ |
| |
| |
| /* We allocate all data in one memory block: the iov vector, |
| the response header and the dataset itself. */ |
| struct dataset |
| { |
| struct datahead head; |
| initgr_response_header resp; |
| char strdata[0]; |
| } *dataset = NULL; |
| |
| if (__glibc_unlikely (debug_level > 0)) |
| { |
| if (he == NULL) |
| dbg_log (_("Haven't found \"%s\" in group cache!"), (char *) key); |
| else |
| dbg_log (_("Reloading \"%s\" in group cache!"), (char *) key); |
| } |
| |
| static service_user *group_database; |
| service_user *nip; |
| int no_more; |
| |
| if (group_database == NULL) |
| no_more = __nss_database_lookup ("group", NULL, |
| "compat [NOTFOUND=return] files", |
| &group_database); |
| else |
| no_more = 0; |
| nip = group_database; |
| |
| /* We always use sysconf even if NGROUPS_MAX is defined. That way, the |
| limit can be raised in the kernel configuration without having to |
| recompile libc. */ |
| long int limit = __sysconf (_SC_NGROUPS_MAX); |
| |
| long int size; |
| if (limit > 0) |
| /* We limit the size of the intially allocated array. */ |
| size = MIN (limit, 64); |
| else |
| /* No fixed limit on groups. Pick a starting buffer size. */ |
| size = 16; |
| |
| long int start = 0; |
| bool all_tryagain = true; |
| bool any_success = false; |
| |
| /* This is temporary memory, we need not (and must not) call |
| mempool_alloc. */ |
| // XXX This really should use alloca. need to change the backends. |
| gid_t *groups = (gid_t *) malloc (size * sizeof (gid_t)); |
| if (__glibc_unlikely (groups == NULL)) |
| /* No more memory. */ |
| goto out; |
| |
| /* Nothing added yet. */ |
| while (! no_more) |
| { |
| long int prev_start = start; |
| enum nss_status status; |
| initgroups_dyn_function fct; |
| fct = __nss_lookup_function (nip, "initgroups_dyn"); |
| |
| if (fct == NULL) |
| { |
| status = compat_call (nip, key, -1, &start, &size, &groups, |
| limit, &errno); |
| |
| if (nss_next_action (nip, NSS_STATUS_UNAVAIL) != NSS_ACTION_CONTINUE) |
| break; |
| } |
| else |
| status = DL_CALL_FCT (fct, (key, -1, &start, &size, &groups, |
| limit, &errno)); |
| |
| /* Remove duplicates. */ |
| long int cnt = prev_start; |
| while (cnt < start) |
| { |
| long int inner; |
| for (inner = 0; inner < prev_start; ++inner) |
| if (groups[inner] == groups[cnt]) |
| break; |
| |
| if (inner < prev_start) |
| groups[cnt] = groups[--start]; |
| else |
| ++cnt; |
| } |
| |
| if (status != NSS_STATUS_TRYAGAIN) |
| all_tryagain = false; |
| |
| /* This is really only for debugging. */ |
| if (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_RETURN) |
| __libc_fatal ("illegal status in internal_getgrouplist"); |
| |
| any_success |= status == NSS_STATUS_SUCCESS; |
| |
| if (status != NSS_STATUS_SUCCESS |
| && nss_next_action (nip, status) == NSS_ACTION_RETURN) |
| break; |
| |
| if (nip->next == NULL) |
| no_more = -1; |
| else |
| nip = nip->next; |
| } |
| |
| bool all_written; |
| ssize_t total; |
| time_t timeout; |
| out: |
| all_written = true; |
| timeout = MAX_TIMEOUT_VALUE; |
| if (!any_success) |
| { |
| /* Nothing found. Create a negative result record. */ |
| total = sizeof (notfound); |
| |
| if (he != NULL && all_tryagain) |
| { |
| /* If we have an old record available but cannot find one now |
| because the service is not available we keep the old record |
| and make sure it does not get removed. */ |
| if (reload_count != UINT_MAX && dh->nreloads == reload_count) |
| /* Do not reset the value if we never not reload the record. */ |
| dh->nreloads = reload_count - 1; |
| |
| /* Reload with the same time-to-live value. */ |
| timeout = dh->timeout = time (NULL) + db->postimeout; |
| } |
| else |
| { |
| /* We have no data. This means we send the standard reply for this |
| case. */ |
| if (fd != -1 |
| && TEMP_FAILURE_RETRY (send (fd, ¬found, total, |
| MSG_NOSIGNAL)) != total) |
| all_written = false; |
| |
| /* If we have a transient error or cannot permanently store |
| the result, so be it. */ |
| if (all_tryagain || __builtin_expect (db->negtimeout == 0, 0)) |
| { |
| /* Mark the old entry as obsolete. */ |
| if (dh != NULL) |
| dh->usable = false; |
| } |
| else if ((dataset = mempool_alloc (db, (sizeof (struct dataset) |
| + req->key_len), 1)) != NULL) |
| { |
| timeout = datahead_init_neg (&dataset->head, |
| (sizeof (struct dataset) |
| + req->key_len), total, |
| db->negtimeout); |
| |
| /* This is the reply. */ |
| memcpy (&dataset->resp, ¬found, total); |
| |
| /* Copy the key data. */ |
| char *key_copy = memcpy (dataset->strdata, key, req->key_len); |
| |
| /* If necessary, we also propagate the data to disk. */ |
| if (db->persistent) |
| { |
| // XXX async OK? |
| uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1; |
| msync ((void *) pval, |
| ((uintptr_t) dataset & pagesize_m1) |
| + sizeof (struct dataset) + req->key_len, MS_ASYNC); |
| } |
| |
| (void) cache_add (req->type, key_copy, req->key_len, |
| &dataset->head, true, db, uid, he == NULL); |
| |
| pthread_rwlock_unlock (&db->lock); |
| |
| /* Mark the old entry as obsolete. */ |
| if (dh != NULL) |
| dh->usable = false; |
| } |
| } |
| } |
| else |
| { |
| |
| total = offsetof (struct dataset, strdata) + start * sizeof (int32_t); |
| |
| /* If we refill the cache, first assume the reconrd did not |
| change. Allocate memory on the cache since it is likely |
| discarded anyway. If it turns out to be necessary to have a |
| new record we can still allocate real memory. */ |
| bool alloca_used = false; |
| dataset = NULL; |
| |
| if (he == NULL) |
| dataset = (struct dataset *) mempool_alloc (db, total + req->key_len, |
| 1); |
| |
| if (dataset == NULL) |
| { |
| /* We cannot permanently add the result in the moment. But |
| we can provide the result as is. Store the data in some |
| temporary memory. */ |
| dataset = (struct dataset *) alloca (total + req->key_len); |
| |
| /* We cannot add this record to the permanent database. */ |
| alloca_used = true; |
| } |
| |
| timeout = datahead_init_pos (&dataset->head, total + req->key_len, |
| total - offsetof (struct dataset, resp), |
| he == NULL ? 0 : dh->nreloads + 1, |
| db->postimeout); |
| |
| dataset->resp.version = NSCD_VERSION; |
| dataset->resp.found = 1; |
| dataset->resp.ngrps = start; |
| |
| char *cp = dataset->strdata; |
| |
| /* Copy the GID values. If the size of the types match this is |
| very simple. */ |
| if (sizeof (gid_t) == sizeof (int32_t)) |
| cp = mempcpy (cp, groups, start * sizeof (gid_t)); |
| else |
| { |
| gid_t *gcp = (gid_t *) cp; |
| |
| for (int i = 0; i < start; ++i) |
| *gcp++ = groups[i]; |
| |
| cp = (char *) gcp; |
| } |
| |
| /* Finally the user name. */ |
| memcpy (cp, key, req->key_len); |
| |
| assert (cp == dataset->strdata + total - offsetof (struct dataset, |
| strdata)); |
| |
| /* Now we can determine whether on refill we have to create a new |
| record or not. */ |
| if (he != NULL) |
| { |
| assert (fd == -1); |
| |
| if (total + req->key_len == dh->allocsize |
| && total - offsetof (struct dataset, resp) == dh->recsize |
| && memcmp (&dataset->resp, dh->data, |
| dh->allocsize - offsetof (struct dataset, resp)) == 0) |
| { |
| /* The data has not changed. We will just bump the |
| timeout value. Note that the new record has been |
| allocated on the stack and need not be freed. */ |
| dh->timeout = dataset->head.timeout; |
| ++dh->nreloads; |
| } |
| else |
| { |
| /* We have to create a new record. Just allocate |
| appropriate memory and copy it. */ |
| struct dataset *newp |
| = (struct dataset *) mempool_alloc (db, total + req->key_len, |
| 1); |
| if (newp != NULL) |
| { |
| /* Adjust pointer into the memory block. */ |
| cp = (char *) newp + (cp - (char *) dataset); |
| |
| dataset = memcpy (newp, dataset, total + req->key_len); |
| alloca_used = false; |
| } |
| |
| /* Mark the old record as obsolete. */ |
| dh->usable = false; |
| } |
| } |
| else |
| { |
| /* We write the dataset before inserting it to the database |
| since while inserting this thread might block and so would |
| unnecessarily let the receiver wait. */ |
| assert (fd != -1); |
| |
| #ifdef HAVE_SENDFILE |
| if (__builtin_expect (db->mmap_used, 1) && !alloca_used) |
| { |
| assert (db->wr_fd != -1); |
| assert ((char *) &dataset->resp > (char *) db->data); |
| assert ((char *) dataset - (char *) db->head |
| + total |
| <= (sizeof (struct database_pers_head) |
| + db->head->module * sizeof (ref_t) |
| + db->head->data_size)); |
| ssize_t written = sendfileall (fd, db->wr_fd, |
| (char *) &dataset->resp |
| - (char *) db->head, |
| dataset->head.recsize); |
| if (written != dataset->head.recsize) |
| { |
| # ifndef __ASSUME_SENDFILE |
| if (written == -1 && errno == ENOSYS) |
| goto use_write; |
| # endif |
| all_written = false; |
| } |
| } |
| else |
| # ifndef __ASSUME_SENDFILE |
| use_write: |
| # endif |
| #endif |
| if (writeall (fd, &dataset->resp, dataset->head.recsize) |
| != dataset->head.recsize) |
| all_written = false; |
| } |
| |
| |
| /* Add the record to the database. But only if it has not been |
| stored on the stack. */ |
| if (! alloca_used) |
| { |
| /* If necessary, we also propagate the data to disk. */ |
| if (db->persistent) |
| { |
| // XXX async OK? |
| uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1; |
| msync ((void *) pval, |
| ((uintptr_t) dataset & pagesize_m1) + total + |
| req->key_len, MS_ASYNC); |
| } |
| |
| (void) cache_add (INITGROUPS, cp, req->key_len, &dataset->head, true, |
| db, uid, he == NULL); |
| |
| pthread_rwlock_unlock (&db->lock); |
| } |
| } |
| |
| free (groups); |
| |
| if (__builtin_expect (!all_written, 0) && debug_level > 0) |
| { |
| char buf[256]; |
| dbg_log (_("short write in %s: %s"), __FUNCTION__, |
| strerror_r (errno, buf, sizeof (buf))); |
| } |
| |
| return timeout; |
| } |
| |
| |
| void |
| addinitgroups (struct database_dyn *db, int fd, request_header *req, void *key, |
| uid_t uid) |
| { |
| addinitgroupsX (db, fd, req, key, uid, NULL, NULL); |
| } |
| |
| |
| time_t |
| readdinitgroups (struct database_dyn *db, struct hashentry *he, |
| struct datahead *dh) |
| { |
| request_header req = |
| { |
| .type = INITGROUPS, |
| .key_len = he->len |
| }; |
| |
| return addinitgroupsX (db, -1, &req, db->data + he->key, he->owner, he, dh); |
| } |