s3: Move the share_mode_lock handling to its own file

Signed-off-by: Jeremy Allison <jra@samba.org>

1 files changed, 463 insertions, 0 deletions

diff --git a/source3/locking/share_mode_lock.c b/source3/locking/share_mode_lock.c
new file mode 100644
index 0000000000..1fb96998d7
--- /dev/null
+++ b/source3/locking/share_mode_lock.c
@@ -0,0 +1,463 @@
+/*
+   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;
+	}
+}