/*
Unix SMB/CIFS implementation.
Locking functions
Copyright (C) Andrew Tridgell 1992-2000
Copyright (C) Jeremy Allison 1992-2006
Copyright (C) Volker Lendecke 2005
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; either version 3 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 .
Revision History:
12 aug 96: Erik.Devriendt@te6.siemens.be
added support for shared memory implementation of share mode locking
May 1997. Jeremy Allison (jallison@whistle.com). Modified share mode
locking to deal with multiple share modes per open file.
September 1997. Jeremy Allison (jallison@whistle.com). Added oplock
support.
rewritten completely to use new tdb code. Tridge, Dec '99
Added POSIX locking support. Jeremy Allison (jeremy@valinux.com), Apr. 2000.
Added Unix Extensions POSIX locking support. Jeremy Allison Mar 2006.
*/
#include "includes.h"
#include "system/filesys.h"
#include "locking/proto.h"
#include "smbd/globals.h"
#include "dbwrap/dbwrap.h"
#include "dbwrap/dbwrap_open.h"
#include "../libcli/security/security.h"
#include "serverid.h"
#include "messages.h"
#include "util_tdb.h"
#include "../librpc/gen_ndr/ndr_open_files.h"
#include "source3/lib/dbwrap/dbwrap_watch.h"
#include "locking/leases_db.h"
#include "../lib/util/memcache.h"
#undef DBGC_CLASS
#define DBGC_CLASS DBGC_LOCKING
#define NO_LOCKING_COUNT (-1)
/* the locking database handle */
static struct db_context *lock_db;
static bool locking_init_internal(bool read_only)
{
struct db_context *backend;
char *db_path;
brl_init(read_only);
if (lock_db)
return True;
db_path = lock_path("locking.tdb");
if (db_path == NULL) {
return false;
}
backend = db_open(NULL, db_path,
SMB_OPEN_DATABASE_TDB_HASH_SIZE,
TDB_DEFAULT|TDB_VOLATILE|TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH,
read_only?O_RDONLY:O_RDWR|O_CREAT, 0644,
DBWRAP_LOCK_ORDER_1, DBWRAP_FLAG_NONE);
TALLOC_FREE(db_path);
if (!backend) {
DEBUG(0,("ERROR: Failed to initialise locking database\n"));
return False;
}
lock_db = db_open_watched(NULL, backend, server_messaging_context());
if (lock_db == NULL) {
DBG_ERR("db_open_watched failed\n");
TALLOC_FREE(backend);
return false;
}
if (!posix_locking_init(read_only)) {
TALLOC_FREE(lock_db);
return False;
}
return True;
}
bool locking_init(void)
{
return locking_init_internal(false);
}
bool locking_init_readonly(void)
{
return locking_init_internal(true);
}
/*******************************************************************
Deinitialize the share_mode management.
******************************************************************/
bool locking_end(void)
{
brl_shutdown();
TALLOC_FREE(lock_db);
return true;
}
/*******************************************************************
Form a static locking key for a dev/inode pair.
******************************************************************/
static TDB_DATA locking_key(const struct file_id *id)
{
return make_tdb_data((const uint8_t *)id, sizeof(*id));
}
/*******************************************************************
Share mode cache utility functions that store/delete/retrieve
entries from memcache.
For now share the statcache (global cache) memory space. If
a lock record gets orphaned (which shouldn't happen as we're
using the same locking_key data as lookup) it will eventually
fall out of the cache via the normal LRU trim mechanism. If
necessary we can always make this a separate (smaller) cache.
******************************************************************/
static const DATA_BLOB memcache_key(const struct file_id *id)
{
return data_blob_const((const void *)id, sizeof(*id));
}
static void share_mode_memcache_delete(struct share_mode_data *d)
{
const DATA_BLOB key = memcache_key(&d->id);
DEBUG(10,("deleting entry for file %s seq 0x%llu key %s\n",
d->base_name,
(unsigned long long) d->sequence_number,
file_id_string(talloc_tos(), &d->id)));
memcache_delete(NULL,
SHARE_MODE_LOCK_CACHE,
key);
}
static void share_mode_memcache_store(struct share_mode_data *d)
{
const DATA_BLOB key = memcache_key(&d->id);
DEBUG(10,("stored entry for file %s seq 0x%llu key %s\n",
d->base_name,
(unsigned long long) d->sequence_number,
file_id_string(talloc_tos(), &d->id)));
/* Ensure everything stored in the cache is pristine. */
d->modified = false;
d->fresh = false;
/*
* Ensure the memory going into the cache
* doesn't have a destructor so it can be
* cleanly freed by share_mode_memcache_delete().
*/
talloc_set_destructor(d, NULL);
/* Cache will own d after this call. */
memcache_add_talloc(NULL,
SHARE_MODE_LOCK_CACHE,
key,
&d);
}
/*
* NB. We use ndr_pull_hyper on a stack-created
* struct ndr_pull with no talloc allowed, as we
* need this to be really fast as an ndr-peek into
* the first 8 bytes of the blob.
*/
static enum ndr_err_code get_blob_sequence_number(DATA_BLOB *blob,
uint64_t *pseq)
{
struct ndr_pull ndr = {.data = blob->data, .data_size = blob->length};
NDR_CHECK(ndr_pull_hyper(&ndr, NDR_SCALARS, pseq));
return NDR_ERR_SUCCESS;
}
static int share_mode_data_nofree_destructor(struct share_mode_data *d)
{
return -1;
}
static struct share_mode_data *share_mode_memcache_fetch(TALLOC_CTX *mem_ctx,
const TDB_DATA id_key,
DATA_BLOB *blob)
{
enum ndr_err_code ndr_err;
struct share_mode_data *d;
uint64_t sequence_number;
void *ptr;
struct file_id id;
DATA_BLOB key;
/* Ensure this is a locking_key record. */
if (id_key.dsize != sizeof(id)) {
return NULL;
}
memcpy(&id, id_key.dptr, id_key.dsize);
key = memcache_key(&id);
ptr = memcache_lookup_talloc(NULL,
SHARE_MODE_LOCK_CACHE,
key);
if (ptr == NULL) {
DEBUG(10,("failed to find entry for key %s\n",
file_id_string(mem_ctx, &id)));
return NULL;
}
/* sequence number key is at start of blob. */
ndr_err = get_blob_sequence_number(blob, &sequence_number);
if (ndr_err != NDR_ERR_SUCCESS) {
/* Bad blob. Remove entry. */
DEBUG(10,("bad blob %u key %s\n",
(unsigned int)ndr_err,
file_id_string(mem_ctx, &id)));
memcache_delete(NULL,
SHARE_MODE_LOCK_CACHE,
key);
return NULL;
}
d = (struct share_mode_data *)ptr;
if (d->sequence_number != sequence_number) {
DEBUG(10,("seq changed (cached 0x%llu) (new 0x%llu) "
"for key %s\n",
(unsigned long long)d->sequence_number,
(unsigned long long)sequence_number,
file_id_string(mem_ctx, &id)));
/* Cache out of date. Remove entry. */
memcache_delete(NULL,
SHARE_MODE_LOCK_CACHE,
key);
return NULL;
}
/* Move onto mem_ctx. */
d = talloc_move(mem_ctx, &ptr);
/*
* Now we own d, prevent the cache from freeing it
* when we delete the entry.
*/
talloc_set_destructor(d, share_mode_data_nofree_destructor);
/* Remove from the cache. We own it now. */
memcache_delete(NULL,
SHARE_MODE_LOCK_CACHE,
key);
/* And reset the destructor to none. */
talloc_set_destructor(d, NULL);
DEBUG(10,("fetched entry for file %s seq 0x%llu key %s\n",
d->base_name,
(unsigned long long)d->sequence_number,
file_id_string(mem_ctx, &id)));
return d;
}
/*******************************************************************
Get all share mode entries for a dev/inode pair.
********************************************************************/
static struct share_mode_data *parse_share_modes(TALLOC_CTX *mem_ctx,
const TDB_DATA key,
const TDB_DATA dbuf)
{
struct share_mode_data *d;
enum ndr_err_code ndr_err;
uint32_t i;
DATA_BLOB blob;
blob.data = dbuf.dptr;
blob.length = dbuf.dsize;
/* See if we already have a cached copy of this key. */
d = share_mode_memcache_fetch(mem_ctx, key, &blob);
if (d != NULL) {
return d;
}
d = talloc(mem_ctx, struct share_mode_data);
if (d == NULL) {
DEBUG(0, ("talloc failed\n"));
goto fail;
}
ndr_err = ndr_pull_struct_blob_all(
&blob, d, d, (ndr_pull_flags_fn_t)ndr_pull_share_mode_data);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
DEBUG(1, ("ndr_pull_share_mode_lock failed: %s\n",
ndr_errstr(ndr_err)));
goto fail;
}
/*
* Initialize the values that are [skip] in the idl. The NDR code does
* not initialize them.
*/
for (i=0; inum_share_modes; i++) {
struct share_mode_entry *e = &d->share_modes[i];
e->stale = false;
e->lease = NULL;
if (e->op_type != LEASE_OPLOCK) {
continue;
}
if (e->lease_idx >= d->num_leases) {
continue;
}
e->lease = &d->leases[e->lease_idx];
}
d->modified = false;
d->fresh = false;
if (DEBUGLEVEL >= 10) {
DEBUG(10, ("parse_share_modes:\n"));
NDR_PRINT_DEBUG(share_mode_data, d);
}
return d;
fail:
TALLOC_FREE(d);
return NULL;
}
/*******************************************************************
Create a storable data blob from a modified share_mode_data struct.
********************************************************************/
static TDB_DATA unparse_share_modes(struct share_mode_data *d)
{
DATA_BLOB blob;
enum ndr_err_code ndr_err;
if (DEBUGLEVEL >= 10) {
DEBUG(10, ("unparse_share_modes:\n"));
NDR_PRINT_DEBUG(share_mode_data, d);
}
share_mode_memcache_delete(d);
/* Update the sequence number. */
d->sequence_number += 1;
remove_stale_share_mode_entries(d);
if (d->num_share_modes == 0) {
DEBUG(10, ("No used share mode found\n"));
return make_tdb_data(NULL, 0);
}
ndr_err = ndr_push_struct_blob(
&blob, d, d, (ndr_push_flags_fn_t)ndr_push_share_mode_data);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
smb_panic("ndr_push_share_mode_lock failed");
}
return make_tdb_data(blob.data, blob.length);
}
/*******************************************************************
If modified, store the share_mode_data back into the database.
********************************************************************/
static int share_mode_data_destructor(struct share_mode_data *d)
{
NTSTATUS status;
TDB_DATA data;
if (!d->modified) {
return 0;
}
data = unparse_share_modes(d);
if (data.dptr == NULL) {
if (!d->fresh) {
/* There has been an entry before, delete it */
status = dbwrap_record_delete(d->record);
if (!NT_STATUS_IS_OK(status)) {
char *errmsg;
DEBUG(0, ("delete_rec returned %s\n",
nt_errstr(status)));
if (asprintf(&errmsg, "could not delete share "
"entry: %s\n",
nt_errstr(status)) == -1) {
smb_panic("could not delete share"
"entry");
}
smb_panic(errmsg);
}
}
/*
* Nothing to store in cache - allow the normal
* release of record lock and memory free.
*/
return 0;
}
status = dbwrap_record_store(d->record, data, TDB_REPLACE);
if (!NT_STATUS_IS_OK(status)) {
char *errmsg;
DEBUG(0, ("store returned %s\n", nt_errstr(status)));
if (asprintf(&errmsg, "could not store share mode entry: %s",
nt_errstr(status)) == -1) {
smb_panic("could not store share mode entry");
}
smb_panic(errmsg);
}
/*
* Release the record lock before putting in the cache.
*/
TALLOC_FREE(d->record);
/*
* Release the dptr as well before reparenting to NULL
* (in-memory cache) context.
*/
TALLOC_FREE(data.dptr);
/*
* Reparent d into the in-memory cache so it can be reused if the
* sequence number matches. See parse_share_modes()
* for details.
*/
share_mode_memcache_store(d);
return -1;
}
/*******************************************************************
Allocate a new share_mode_data struct, mark it unmodified.
fresh is set to note that currently there is no database entry.
********************************************************************/
static struct share_mode_data *fresh_share_mode_lock(
TALLOC_CTX *mem_ctx, const char *servicepath,
const struct smb_filename *smb_fname,
const struct timespec *old_write_time)
{
struct share_mode_data *d;
if ((servicepath == NULL) || (smb_fname == NULL) ||
(old_write_time == NULL)) {
return NULL;
}
d = talloc_zero(mem_ctx, struct share_mode_data);
if (d == NULL) {
goto fail;
}
/* New record - new sequence number. */
generate_random_buffer((uint8_t *)&d->sequence_number, 8);
d->base_name = talloc_strdup(d, smb_fname->base_name);
if (d->base_name == NULL) {
goto fail;
}
if (smb_fname->stream_name != NULL) {
d->stream_name = talloc_strdup(d, smb_fname->stream_name);
if (d->stream_name == NULL) {
goto fail;
}
}
d->servicepath = talloc_strdup(d, servicepath);
if (d->servicepath == NULL) {
goto fail;
}
d->old_write_time = *old_write_time;
d->modified = false;
d->fresh = true;
return d;
fail:
DEBUG(0, ("talloc failed\n"));
TALLOC_FREE(d);
return NULL;
}
/*******************************************************************
Either fetch a share mode from the database, or allocate a fresh
one if the record doesn't exist.
********************************************************************/
static struct share_mode_lock *get_share_mode_lock_internal(
TALLOC_CTX *mem_ctx, struct file_id id,
const char *servicepath, const struct smb_filename *smb_fname,
const struct timespec *old_write_time)
{
struct share_mode_lock *lck;
struct share_mode_data *d;
struct db_record *rec;
TDB_DATA key = locking_key(&id);
TDB_DATA value;
rec = dbwrap_fetch_locked(lock_db, mem_ctx, key);
if (rec == NULL) {
DEBUG(3, ("Could not lock share entry\n"));
return NULL;
}
value = dbwrap_record_get_value(rec);
if (value.dptr == NULL) {
d = fresh_share_mode_lock(mem_ctx, servicepath, smb_fname,
old_write_time);
} else {
d = parse_share_modes(mem_ctx, key, value);
}
if (d == NULL) {
DEBUG(5, ("get_share_mode_lock_internal: "
"Could not get share mode lock\n"));
TALLOC_FREE(rec);
return NULL;
}
d->id = id;
d->record = talloc_move(d, &rec);
talloc_set_destructor(d, share_mode_data_destructor);
lck = talloc(mem_ctx, struct share_mode_lock);
if (lck == NULL) {
DEBUG(1, ("talloc failed\n"));
TALLOC_FREE(d);
return NULL;
}
lck->data = talloc_move(lck, &d);
return lck;
}
/*
* We can only ever have one share mode locked. Users of
* get_share_mode_lock never see this, it will be refcounted by
* talloc_reference.
*/
static struct share_mode_lock *the_lock;
static struct file_id the_lock_id;
static int the_lock_destructor(struct share_mode_lock *l)
{
the_lock = NULL;
ZERO_STRUCT(the_lock_id);
return 0;
}
/*******************************************************************
Get a share_mode_lock, Reference counted to allow nested calls.
********************************************************************/
struct share_mode_lock *get_share_mode_lock(
TALLOC_CTX *mem_ctx,
struct file_id id,
const char *servicepath,
const struct smb_filename *smb_fname,
const struct timespec *old_write_time)
{
struct share_mode_lock *lck;
lck = talloc(mem_ctx, struct share_mode_lock);
if (lck == NULL) {
DEBUG(1, ("talloc failed\n"));
return NULL;
}
if (the_lock == NULL) {
the_lock = get_share_mode_lock_internal(
lck, id, servicepath, smb_fname, old_write_time);
if (the_lock == NULL) {
goto fail;
}
talloc_set_destructor(the_lock, the_lock_destructor);
the_lock_id = id;
} else {
if (!file_id_equal(&the_lock_id, &id)) {
DEBUG(1, ("Can not lock two share modes "
"simultaneously\n"));
goto fail;
}
if (talloc_reference(lck, the_lock) == NULL) {
DEBUG(1, ("talloc_reference failed\n"));
goto fail;
}
}
lck->data = the_lock->data;
return lck;
fail:
TALLOC_FREE(lck);
return NULL;
}
static void fetch_share_mode_unlocked_parser(
TDB_DATA key, TDB_DATA data, void *private_data)
{
struct share_mode_lock *lck = talloc_get_type_abort(
private_data, struct share_mode_lock);
if (data.dsize == 0) {
/* Likely a ctdb tombstone record, ignore it */
lck->data = NULL;
return;
}
lck->data = parse_share_modes(lck, key, data);
}
/*******************************************************************
Get a share_mode_lock without locking the database or reference
counting. Used by smbstatus to display existing share modes.
********************************************************************/
struct share_mode_lock *fetch_share_mode_unlocked(TALLOC_CTX *mem_ctx,
struct file_id id)
{
struct share_mode_lock *lck;
TDB_DATA key = locking_key(&id);
NTSTATUS status;
lck = talloc(mem_ctx, struct share_mode_lock);
if (lck == NULL) {
DEBUG(0, ("talloc failed\n"));
return NULL;
}
status = dbwrap_parse_record(
lock_db, key, fetch_share_mode_unlocked_parser, lck);
if (!NT_STATUS_IS_OK(status) ||
(lck->data == NULL)) {
TALLOC_FREE(lck);
return NULL;
}
return lck;
}
struct share_mode_forall_state {
int (*fn)(struct file_id fid, const struct share_mode_data *data,
void *private_data);
void *private_data;
};
static int share_mode_traverse_fn(struct db_record *rec, void *_state)
{
struct share_mode_forall_state *state =
(struct share_mode_forall_state *)_state;
uint32_t i;
TDB_DATA key;
TDB_DATA value;
DATA_BLOB blob;
enum ndr_err_code ndr_err;
struct share_mode_data *d;
struct file_id fid;
int ret;
key = dbwrap_record_get_key(rec);
value = dbwrap_record_get_value(rec);
/* Ensure this is a locking_key record. */
if (key.dsize != sizeof(fid)) {
return 0;
}
memcpy(&fid, key.dptr, sizeof(fid));
d = talloc(talloc_tos(), struct share_mode_data);
if (d == NULL) {
return 0;
}
blob.data = value.dptr;
blob.length = value.dsize;
ndr_err = ndr_pull_struct_blob_all(
&blob, d, d, (ndr_pull_flags_fn_t)ndr_pull_share_mode_data);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
DEBUG(1, ("ndr_pull_share_mode_lock failed\n"));
return 0;
}
for (i=0; inum_share_modes; i++) {
struct share_mode_entry *entry = &d->share_modes[i];
entry->stale = false; /* [skip] in idl */
entry->lease = &d->leases[entry->lease_idx];
}
if (DEBUGLEVEL > 10) {
DEBUG(11, ("parse_share_modes:\n"));
NDR_PRINT_DEBUG(share_mode_data, d);
}
ret = state->fn(fid, d, state->private_data);
TALLOC_FREE(d);
return ret;
}
int share_mode_forall(int (*fn)(struct file_id fid,
const struct share_mode_data *data,
void *private_data),
void *private_data)
{
struct share_mode_forall_state state = {
.fn = fn,
.private_data = private_data
};
NTSTATUS status;
int count;
if (lock_db == NULL) {
return 0;
}
status = dbwrap_traverse_read(lock_db, share_mode_traverse_fn,
&state, &count);
if (!NT_STATUS_IS_OK(status)) {
return -1;
}
return count;
}
struct share_entry_forall_state {
int (*fn)(const struct share_mode_entry *e,
const char *service_path,
const char *base_name,
const char *stream_name,
void *private_data);
void *private_data;
};
static int share_entry_traverse_fn(struct file_id fid,
const struct share_mode_data *data,
void *private_data)
{
struct share_entry_forall_state *state = private_data;
uint32_t i;
for (i=0; inum_share_modes; i++) {
int ret;
ret = state->fn(&data->share_modes[i],
data->servicepath,
data->base_name,
data->stream_name,
state->private_data);
if (ret != 0) {
return ret;
}
}
return 0;
}
/*******************************************************************
Call the specified function on each entry under management by the
share mode system.
********************************************************************/
int share_entry_forall(int (*fn)(const struct share_mode_entry *,
const char *, const char *,
const char *, void *),
void *private_data)
{
struct share_entry_forall_state state = {
.fn = fn, .private_data = private_data };
return share_mode_forall(share_entry_traverse_fn, &state);
}
bool share_mode_cleanup_disconnected(struct file_id fid,
uint64_t open_persistent_id)
{
bool ret = false;
TALLOC_CTX *frame = talloc_stackframe();
unsigned n;
struct share_mode_data *data;
struct share_mode_lock *lck;
bool ok;
lck = get_existing_share_mode_lock(frame, fid);
if (lck == NULL) {
DEBUG(5, ("share_mode_cleanup_disconnected: "
"Could not fetch share mode entry for %s\n",
file_id_string(frame, &fid)));
goto done;
}
data = lck->data;
for (n=0; n < data->num_share_modes; n++) {
struct share_mode_entry *entry = &data->share_modes[n];
if (!server_id_is_disconnected(&entry->pid)) {
struct server_id_buf tmp;
DEBUG(5, ("share_mode_cleanup_disconnected: "
"file (file-id='%s', servicepath='%s', "
"base_name='%s%s%s') "
"is used by server %s ==> do not cleanup\n",
file_id_string(frame, &fid),
data->servicepath,
data->base_name,
(data->stream_name == NULL)
? "" : "', stream_name='",
(data->stream_name == NULL)
? "" : data->stream_name,
server_id_str_buf(entry->pid, &tmp)));
goto done;
}
if (open_persistent_id != entry->share_file_id) {
DEBUG(5, ("share_mode_cleanup_disconnected: "
"entry for file "
"(file-id='%s', servicepath='%s', "
"base_name='%s%s%s') "
"has share_file_id %llu but expected %llu"
"==> do not cleanup\n",
file_id_string(frame, &fid),
data->servicepath,
data->base_name,
(data->stream_name == NULL)
? "" : "', stream_name='",
(data->stream_name == NULL)
? "" : data->stream_name,
(unsigned long long)entry->share_file_id,
(unsigned long long)open_persistent_id));
goto done;
}
}
for (n=0; n < data->num_leases; n++) {
struct share_mode_lease *l = &data->leases[n];
NTSTATUS status;
status = leases_db_del(&l->client_guid, &l->lease_key, &fid);
DEBUG(10, ("%s: leases_db_del returned %s\n", __func__,
nt_errstr(status)));
}
ok = brl_cleanup_disconnected(fid, open_persistent_id);
if (!ok) {
DEBUG(10, ("share_mode_cleanup_disconnected: "
"failed to clean up byte range locks associated "
"with file (file-id='%s', servicepath='%s', "
"base_name='%s%s%s') and open_persistent_id %llu "
"==> do not cleanup\n",
file_id_string(frame, &fid),
data->servicepath,
data->base_name,
(data->stream_name == NULL)
? "" : "', stream_name='",
(data->stream_name == NULL)
? "" : data->stream_name,
(unsigned long long)open_persistent_id));
goto done;
}
DEBUG(10, ("share_mode_cleanup_disconnected: "
"cleaning up %u entries for file "
"(file-id='%s', servicepath='%s', "
"base_name='%s%s%s') "
"from open_persistent_id %llu\n",
data->num_share_modes,
file_id_string(frame, &fid),
data->servicepath,
data->base_name,
(data->stream_name == NULL)
? "" : "', stream_name='",
(data->stream_name == NULL)
? "" : data->stream_name,
(unsigned long long)open_persistent_id));
data->num_share_modes = 0;
data->num_leases = 0;
data->modified = true;
ret = true;
done:
talloc_free(frame);
return ret;
}