+/*
+ 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 <http://www.gnu.org/licenses/>.
+
+ 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"
+
+#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)
+{
+ brl_init(read_only);
+
+ if (lock_db)
+ return True;
+
+ lock_db = db_open(NULL, lock_path("locking.tdb"),
+ lp_open_files_db_hash_size(),
+ TDB_DEFAULT|TDB_VOLATILE|TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH,
+ read_only?O_RDONLY:O_RDWR|O_CREAT, 0644);
+
+ if (!lock_db) {
+ DEBUG(0,("ERROR: Failed to initialise locking database\n"));
+ return False;
+ }
+
+ if (!posix_locking_init(read_only))
+ 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, struct file_id *tmp)
+{
+ *tmp = *id;
+ return make_tdb_data((const uint8_t *)tmp, sizeof(*tmp));
+}
+
+/*******************************************************************
+ 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 dbuf)
+{
+ struct share_mode_data *d;
+ int i;
+ struct server_id *pids;
+ bool *pid_exists;
+ enum ndr_err_code ndr_err;
+ DATA_BLOB blob;
+
+ d = talloc_zero(mem_ctx, struct share_mode_data);
+ if (d == NULL) {
+ DEBUG(0, ("talloc failed\n"));
+ goto fail;
+ }
+
+ blob.data = dbuf.dptr;
+ blob.length = dbuf.dsize;
+
+ ndr_err = ndr_pull_struct_blob(
+ &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"));
+ goto fail;
+ }
+
+ d->modified = false;
+ d->fresh = false;
+
+ if (DEBUGLEVEL >= 10) {
+ DEBUG(10, ("parse_share_modes:\n"));
+ NDR_PRINT_DEBUG(share_mode_data, d);
+ }
+
+ /*
+ * Ensure that each entry has a real process attached.
+ */
+
+ pids = talloc_array(talloc_tos(), struct server_id,
+ d->num_share_modes);
+ if (pids == NULL) {
+ DEBUG(0, ("talloc failed\n"));
+ goto fail;
+ }
+ pid_exists = talloc_array(talloc_tos(), bool, d->num_share_modes);
+ if (pid_exists == NULL) {
+ DEBUG(0, ("talloc failed\n"));
+ goto fail;
+ }
+
+ for (i=0; i<d->num_share_modes; i++) {
+ pids[i] = d->share_modes[i].pid;
+ }
+ if (!serverids_exist(pids, d->num_share_modes, pid_exists)) {
+ DEBUG(0, ("serverid_exists failed\n"));
+ goto fail;
+ }
+
+ i = 0;
+ while (i < d->num_share_modes) {
+ struct share_mode_entry *e = &d->share_modes[i];
+ if (!pid_exists[i]) {
+ *e = d->share_modes[d->num_share_modes-1];
+ d->num_share_modes -= 1;
+ d->modified = True;
+ continue;
+ }
+ i += 1;
+ }
+ TALLOC_FREE(pid_exists);
+ TALLOC_FREE(pids);
+ return d;
+fail:
+ TALLOC_FREE(d);
+ return NULL;
+}
+
+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);
+ }
+
+ 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);
+}
+
+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);
+ }
+ }
+ goto done;
+ }
+
+ 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);
+ }
+
+ done:
+
+ return 0;
+}
+
+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;
+ }
+ 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;
+}
+
+struct share_mode_lock *get_share_mode_lock_fresh(TALLOC_CTX *mem_ctx,
+ const 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 file_id tmp;
+ struct db_record *rec;
+ TDB_DATA key = locking_key(&id, &tmp);
+ 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, value);
+ }
+
+ if (d == NULL) {
+ DEBUG(1, ("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;
+}
+
+struct share_mode_lock *fetch_share_mode_unlocked(TALLOC_CTX *mem_ctx,
+ const struct file_id id)
+{
+ struct share_mode_lock *lck;
+ struct file_id tmp;
+ TDB_DATA key = locking_key(&id, &tmp);
+ TDB_DATA data;
+ NTSTATUS status;
+
+ status = dbwrap_fetch(lock_db, talloc_tos(), key, &data);
+ if (!NT_STATUS_IS_OK(status)) {
+ DEBUG(3, ("Could not fetch share entry\n"));
+ return NULL;
+ }
+ if (data.dptr == NULL) {
+ return NULL;
+ }
+ lck = talloc(mem_ctx, struct share_mode_lock);
+ if (lck == NULL) {
+ TALLOC_FREE(data.dptr);
+ return NULL;
+ }
+ lck->data = parse_share_modes(mem_ctx, data);
+ TALLOC_FREE(data.dptr);
+ if (lck->data == NULL) {
+ TALLOC_FREE(lck);
+ return NULL;
+ }
+ return lck;
+}
+
+struct forall_state {
+ void (*fn)(const struct share_mode_entry *entry,
+ const char *sharepath,
+ const char *fname,
+ void *private_data);
+ void *private_data;
+};
+
+static int traverse_fn(struct db_record *rec, void *_state)
+{
+ struct forall_state *state = (struct 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;
+
+ key = dbwrap_record_get_key(rec);
+ value = dbwrap_record_get_value(rec);
+
+ /* Ensure this is a locking_key record. */
+ if (key.dsize != sizeof(struct file_id))
+ return 0;
+
+ 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(
+ &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; i<d->num_share_modes; i++) {
+ state->fn(&d->share_modes[i],
+ d->servicepath, d->base_name,
+ state->private_data);
+ }
+ TALLOC_FREE(d);
+
+ return 0;
+}
+
+/*******************************************************************
+ Call the specified function on each entry under management by the
+ share mode system.
+********************************************************************/
+
+int share_mode_forall(void (*fn)(const struct share_mode_entry *, const char *,
+ const char *, void *),
+ void *private_data)
+{
+ struct forall_state state;
+ NTSTATUS status;
+ int count;
+
+ if (lock_db == NULL)
+ return 0;
+
+ state.fn = fn;
+ state.private_data = private_data;
+
+ status = dbwrap_traverse_read(lock_db, traverse_fn, (void *)&state,
+ &count);
+
+ if (!NT_STATUS_IS_OK(status)) {
+ return -1;
+ } else {
+ return count;
+ }
+}
git.samba.org / kai / samba.git / commitdiff