diff options
Diffstat (limited to 'REORG.TODO/nscd/initgrcache.c')
| -rw-r--r-- | REORG.TODO/nscd/initgrcache.c | 438 |
1 files changed, 438 insertions, 0 deletions
diff --git a/REORG.TODO/nscd/initgrcache.c b/REORG.TODO/nscd/initgrcache.c new file mode 100644 index 0000000000..4deb483fbb --- /dev/null +++ b/REORG.TODO/nscd/initgrcache.c @@ -0,0 +1,438 @@ +/* Cache handling for host lookup. + Copyright (C) 2004-2017 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); +} |