s3/lib: add smbd_cleanupd.tdb

This will be used between cleanupd and smbd for passing information
about exitted smbd childs.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=12022

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>

source3/lib/cleanupdb.c

@@ -0,0 +1,170 @@
+/*
+   Unix SMB/CIFS implementation.
+   Implementation of reliable cleanup events
+   Copyright (C) Ralph Boehme 2016
+
+   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/>.
+*/
+
+#include "cleanupdb.h"
+
+struct cleanup_key {
+	pid_t pid;
+};
+
+struct cleanup_rec {
+	/* Storing the pid here as well saves a few lines of code */
+	pid_t pid;
+	bool unclean;
+};
+
+static struct tdb_wrap *cleanup_db(void)
+{
+	static struct tdb_wrap *db;
+	char *db_path = NULL;
+	int tdbflags = TDB_INCOMPATIBLE_HASH | TDB_CLEAR_IF_FIRST |
+		TDB_MUTEX_LOCKING;
+
+	if (db != NULL) {
+		return db;
+	}
+
+	db_path = lock_path("smbd_cleanupd.tdb");
+	if (db_path == NULL) {
+		return NULL;
+	}
+
+	db = tdb_wrap_open(NULL, db_path, 0, tdbflags,
+			   O_CREAT | O_RDWR, 0644);
+	if (db == NULL) {
+		DBG_ERR("Failed to open smbd_cleanupd.tdb\n");
+	}
+
+	TALLOC_FREE(db_path);
+	return db;
+}
+
+bool cleanupdb_store_child(const pid_t pid, const bool unclean)
+{
+	struct tdb_wrap *db;
+	struct cleanup_key key = { .pid = pid };
+	struct cleanup_rec rec = { .pid = pid, .unclean = unclean };
+	TDB_DATA tdbkey = { .dptr = (uint8_t *)&key, .dsize = sizeof(key) };
+	TDB_DATA tdbdata = { .dptr = (uint8_t *)&key, .dsize = sizeof(rec) };
+	int result;
+
+	db = cleanup_db();
+	if (db == NULL) {
+		return false;
+	}
+
+	result = tdb_store(db->tdb, tdbkey, tdbdata, TDB_REPLACE);
+	if (result != 0) {
+		DBG_ERR("tdb_store failed for pid %d\n", (int)pid);
+		return false;
+	}
+
+	return true;
+}
+
+bool cleanupdb_delete_child(const pid_t pid)
+{
+	struct tdb_wrap *db;
+	struct cleanup_key key = { .pid = pid };
+	TDB_DATA tdbkey = { .dptr = (uint8_t *)&key, .dsize = sizeof(key) };
+	int result;
+
+	db = cleanup_db();
+	if (db == NULL) {
+		return false;
+	}
+
+	result = tdb_delete(db->tdb, tdbkey);
+	if (result != 0) {
+		DBG_ERR("tdb_delete failed for pid %d\n", (int)pid);
+		return false;
+	}
+
+	return true;
+}
+
+static bool cleanup_rec_parse(TDB_DATA tdbdata,
+			      struct cleanup_rec *cleanup_rec)
+{
+	if (tdbdata.dsize != sizeof(struct cleanup_rec)) {
+		DBG_ERR("Found invalid value length %d in cleanup.tdb\n",
+			(int)tdbdata.dsize);
+		return false;
+	}
+
+	memcpy(cleanup_rec, tdbdata.dptr, sizeof(struct cleanup_rec));
+
+	return true;
+}
+
+struct cleanup_read_state {
+	int (*fn)(const pid_t pid, const bool cleanup, void *private_data);
+	void *private_data;
+};
+
+static int cleanup_traverse_fn(struct tdb_context *tdb,
+			       TDB_DATA key, TDB_DATA value,
+			       void *private_data)
+{
+	struct cleanup_read_state *state =
+		(struct cleanup_read_state *)private_data;
+	struct cleanup_rec rec;
+	bool ok;
+	int result;
+
+	ok = cleanup_rec_parse(value, &rec);
+	if (!ok) {
+		return -1;
+	}
+
+	result = state->fn(rec.pid, rec.unclean, state->private_data);
+	if (result != 0) {
+		return -1;
+	}
+
+	return 0;
+}
+
+int cleanupdb_traverse_read(int (*fn)(const pid_t pid,
+				      const bool cleanup,
+				      void *private_data),
+			    void *private_data)
+{
+	struct tdb_wrap *db;
+	struct cleanup_read_state state;
+	int result;
+
+	db = cleanup_db();
+	if (db == NULL) {
+		return -1;
+	}
+
+	state = (struct cleanup_read_state) {
+		.fn = fn,
+		.private_data = private_data
+	};
+
+	result = tdb_traverse_read(db->tdb, cleanup_traverse_fn, &state);
+	if (result < 0) {
+		DBG_ERR("tdb_traverse_read failed\n");
+		return -1;
+	}
+
+	return result;
+}

source3/lib/cleanupdb.h

@@ -0,0 +1,30 @@
+/*
+   Unix SMB/CIFS implementation.
+   Implementation of reliable cleanup events
+   Copyright (C) Ralph Boehme 2016
+
+   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/>.
+*/
+
+#include "includes.h"
+#include "system/filesys.h"
+#include "util_tdb.h"
+#include "lib/tdb_wrap/tdb_wrap.h"
+
+bool cleanupdb_store_child(const pid_t pid, const bool unclean);
+bool cleanupdb_delete_child(const pid_t pid);
+int cleanupdb_traverse_read(int (*fn)(const pid_t pid,
+				      const bool cleanup,
+				      void *private_data),
+			    void *private_data);

source3/wscript_build

@@ -345,7 +345,8 @@ bld.SAMBA3_SUBSYSTEM('samba3core',
                    lib/tevent_wait.c
                    lib/idmap_cache.c
                    lib/util_ea.c
-                   lib/background.c''',
+                   lib/background.c
+                   lib/cleanupdb.c''',
                    deps='''
                         samba3util
                         LIBTSOCKET