+++ /dev/null
-/*
- Unix SMB/CIFS implementation.
- Samba internal messaging functions
- Copyright (C) 2007 by Volker Lendecke
-
- 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/>.
-*/
-
-/**
- @defgroup messages Internal messaging framework
- @{
- @file messages.c
-
- @brief Module for internal messaging between Samba daemons.
-
- The idea is that if a part of Samba wants to do communication with
- another Samba process then it will do a message_register() of a
- dispatch function, and use message_send_pid() to send messages to
- that process.
-
- The dispatch function is given the pid of the sender, and it can
- use that to reply by message_send_pid(). See ping_message() for a
- simple example.
-
- @caution Dispatch functions must be able to cope with incoming
- messages on an *odd* byte boundary.
-
- This system doesn't have any inherent size limitations but is not
- very efficient for large messages or when messages are sent in very
- quick succession.
-
-*/
-
-#include "includes.h"
-#include "system/filesys.h"
-#include "messages.h"
-#include "serverid.h"
-#include "lib/tdb_wrap/tdb_wrap.h"
-#include "lib/param/param.h"
-
-struct messaging_tdb_context {
- struct messaging_context *msg_ctx;
- struct tdb_wrap *tdb;
- struct tevent_signal *se;
- int received_messages;
- bool *have_context;
-};
-
-static NTSTATUS messaging_tdb_send(struct messaging_context *msg_ctx,
- struct server_id pid, int msg_type,
- const DATA_BLOB *data,
- struct messaging_backend *backend);
-static void message_dispatch(struct messaging_context *msg_ctx);
-
-static void messaging_tdb_signal_handler(struct tevent_context *ev_ctx,
- struct tevent_signal *se,
- int signum, int count,
- void *_info, void *private_data)
-{
- struct messaging_tdb_context *ctx = talloc_get_type(private_data,
- struct messaging_tdb_context);
-
- ctx->received_messages++;
-
- DEBUG(10, ("messaging_tdb_signal_handler: sig[%d] count[%d] msgs[%d]\n",
- signum, count, ctx->received_messages));
-
- message_dispatch(ctx->msg_ctx);
-}
-
-static int messaging_tdb_context_destructor(struct messaging_tdb_context *ctx);
-
-/****************************************************************************
- Initialise the messaging functions.
-****************************************************************************/
-
-NTSTATUS messaging_tdb_init(struct messaging_context *msg_ctx,
- TALLOC_CTX *mem_ctx,
- struct messaging_backend **presult)
-{
- struct messaging_backend *result;
- struct messaging_tdb_context *ctx;
- struct loadparm_context *lp_ctx;
- static bool have_context = false;
- const char *fname;
-
- if (have_context) {
- DEBUG(0, ("No two messaging contexts per process\n"));
- return NT_STATUS_OBJECT_NAME_COLLISION;
- }
-
- if (!(result = talloc(mem_ctx, struct messaging_backend))) {
- DEBUG(0, ("talloc failed\n"));
- return NT_STATUS_NO_MEMORY;
- }
-
- lp_ctx = loadparm_init_s3(result, loadparm_s3_helpers());
- if (lp_ctx == NULL) {
- DEBUG(0, ("loadparm_init_s3 failed\n"));
- TALLOC_FREE(result);
- return NT_STATUS_INTERNAL_ERROR;
- }
-
- ctx = talloc_zero(result, struct messaging_tdb_context);
- if (!ctx) {
- DEBUG(0, ("talloc failed\n"));
- TALLOC_FREE(result);
- return NT_STATUS_NO_MEMORY;
- }
- result->private_data = ctx;
- result->send_fn = messaging_tdb_send;
-
- ctx->msg_ctx = msg_ctx;
- ctx->have_context = &have_context;
-
- fname = lock_path("messages.tdb");
-
- ctx->tdb = tdb_wrap_open(
- ctx, fname, lpcfg_tdb_hash_size(lp_ctx, fname),
- lpcfg_tdb_flags(lp_ctx, TDB_CLEAR_IF_FIRST|TDB_DEFAULT|
- TDB_VOLATILE| TDB_INCOMPATIBLE_HASH),
- O_RDWR|O_CREAT,0600);
-
- talloc_unlink(result, lp_ctx);
-
- if (!ctx->tdb) {
- NTSTATUS status = map_nt_error_from_unix(errno);
- DEBUG(2, ("ERROR: Failed to initialise messages database: "
- "%s\n", strerror(errno)));
- TALLOC_FREE(result);
- return status;
- }
-
- ctx->se = tevent_add_signal(msg_ctx->event_ctx,
- ctx,
- SIGUSR1, 0,
- messaging_tdb_signal_handler,
- ctx);
- if (!ctx->se) {
- NTSTATUS status = map_nt_error_from_unix(errno);
- DEBUG(0, ("ERROR: Failed to initialise messages signal handler: "
- "%s\n", strerror(errno)));
- TALLOC_FREE(result);
- return status;
- }
-
- sec_init();
-
- have_context = true;
- talloc_set_destructor(ctx, messaging_tdb_context_destructor);
-
- *presult = result;
- return NT_STATUS_OK;
-}
-
-static int messaging_tdb_context_destructor(struct messaging_tdb_context *ctx)
-{
- SMB_ASSERT(*ctx->have_context);
- *ctx->have_context = false;
- return 0;
-}
-
-bool messaging_tdb_parent_init(TALLOC_CTX *mem_ctx)
-{
- struct tdb_wrap *db;
- struct loadparm_context *lp_ctx;
- const char *fname;
-
- lp_ctx = loadparm_init_s3(mem_ctx, loadparm_s3_helpers());
- if (lp_ctx == NULL) {
- DEBUG(0, ("loadparm_init_s3 failed\n"));
- return false;
- }
-
- /*
- * Open the tdb in the parent process (smbd) so that our
- * CLEAR_IF_FIRST optimization in tdb_reopen_all can properly
- * work.
- */
-
- fname = lock_path("messages.tdb");
- db = tdb_wrap_open(
- mem_ctx, fname, lpcfg_tdb_hash_size(lp_ctx, fname),
- lpcfg_tdb_flags(lp_ctx, TDB_CLEAR_IF_FIRST|TDB_DEFAULT|
- TDB_VOLATILE|TDB_INCOMPATIBLE_HASH),
- O_RDWR|O_CREAT,0600);
- talloc_unlink(mem_ctx, lp_ctx);
- if (db == NULL) {
- DEBUG(1, ("could not open messaging.tdb: %s\n",
- strerror(errno)));
- return false;
- }
- return true;
-}
-
-/*******************************************************************
- Form a static tdb key from a pid.
-******************************************************************/
-
-static TDB_DATA message_key_pid(TALLOC_CTX *mem_ctx, struct server_id pid)
-{
- char *key;
- TDB_DATA kbuf;
-
- key = talloc_asprintf(mem_ctx, "PID/%s", procid_str_static(&pid));
-
- SMB_ASSERT(key != NULL);
-
- kbuf.dptr = (uint8 *)key;
- kbuf.dsize = strlen(key)+1;
- return kbuf;
-}
-
-/*******************************************************************
- Called when a process has terminated abnormally. Remove all messages
- pending for it.
-******************************************************************/
-
-NTSTATUS messaging_tdb_cleanup(struct messaging_context *msg_ctx,
- struct server_id pid)
-{
- struct messaging_tdb_context *ctx = talloc_get_type(
- msg_ctx->local->private_data,
- struct messaging_tdb_context);
- struct tdb_wrap *tdb = ctx->tdb;
- TDB_DATA key;
- TALLOC_CTX *frame = talloc_stackframe();
-
- key = message_key_pid(frame, pid);
- /*
- * We have to lock the key to avoid
- * races in case the server_id was
- * re-used and is active (a remote
- * possibility, true). We only
- * clean up the database if we
- * know server_id doesn't exist
- * while checked under the chainlock.
- */
- if (tdb_chainlock(tdb->tdb, key) != 0) {
- TALLOC_FREE(frame);
- return NT_STATUS_LOCK_NOT_GRANTED;
- }
- if (!serverid_exists(&pid)) {
- (void)tdb_delete(tdb->tdb, key);
- }
- tdb_chainunlock(tdb->tdb, key);
- TALLOC_FREE(frame);
- return NT_STATUS_OK;
-}
-
-/*
- Fetch the messaging array for a process
- */
-
-static NTSTATUS messaging_tdb_fetch(TDB_CONTEXT *msg_tdb,
- TDB_DATA key,
- TALLOC_CTX *mem_ctx,
- struct messaging_array **presult)
-{
- struct messaging_array *result;
- TDB_DATA data;
- DATA_BLOB blob;
- enum ndr_err_code ndr_err;
-
- if (!(result = talloc_zero(mem_ctx, struct messaging_array))) {
- return NT_STATUS_NO_MEMORY;
- }
-
- data = tdb_fetch(msg_tdb, key);
-
- if (data.dptr == NULL) {
- *presult = result;
- return NT_STATUS_OK;
- }
-
- blob = data_blob_const(data.dptr, data.dsize);
-
- ndr_err = ndr_pull_struct_blob_all(
- &blob, result, result,
- (ndr_pull_flags_fn_t)ndr_pull_messaging_array);
-
- SAFE_FREE(data.dptr);
-
- if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
- TALLOC_FREE(result);
- return ndr_map_error2ntstatus(ndr_err);
- }
-
- if (DEBUGLEVEL >= 10) {
- DEBUG(10, ("messaging_tdb_fetch:\n"));
- NDR_PRINT_DEBUG(messaging_array, result);
- }
-
- *presult = result;
- return NT_STATUS_OK;
-}
-
-/*
- Store a messaging array for a pid
-*/
-
-static NTSTATUS messaging_tdb_store(TDB_CONTEXT *msg_tdb,
- TDB_DATA key,
- struct messaging_array *array)
-{
- TDB_DATA data;
- DATA_BLOB blob;
- enum ndr_err_code ndr_err;
- TALLOC_CTX *mem_ctx;
- int ret;
-
- if (array->num_messages == 0) {
- tdb_delete(msg_tdb, key);
- return NT_STATUS_OK;
- }
-
- if (!(mem_ctx = talloc_new(array))) {
- return NT_STATUS_NO_MEMORY;
- }
-
- ndr_err = ndr_push_struct_blob(&blob, mem_ctx, array,
- (ndr_push_flags_fn_t)ndr_push_messaging_array);
-
- if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
- talloc_free(mem_ctx);
- return ndr_map_error2ntstatus(ndr_err);
- }
-
- if (DEBUGLEVEL >= 10) {
- DEBUG(10, ("messaging_tdb_store:\n"));
- NDR_PRINT_DEBUG(messaging_array, array);
- }
-
- data.dptr = blob.data;
- data.dsize = blob.length;
-
- ret = tdb_store(msg_tdb, key, data, TDB_REPLACE);
- TALLOC_FREE(mem_ctx);
-
- return (ret == 0) ? NT_STATUS_OK : NT_STATUS_INTERNAL_DB_CORRUPTION;
-}
-
-/****************************************************************************
- Notify a process that it has a message. If the process doesn't exist
- then delete its record in the database.
-****************************************************************************/
-
-static NTSTATUS message_notify(struct server_id procid)
-{
- pid_t pid = procid.pid;
- int ret;
- uid_t euid = geteuid();
-
- /*
- * Doing kill with a non-positive pid causes messages to be
- * sent to places we don't want.
- */
-
- SMB_ASSERT(pid > 0);
- if (pid <= 0) {
- return NT_STATUS_INVALID_HANDLE;
- }
-
- if (euid != 0) {
- /* If we're not root become so to send the message. */
- save_re_uid();
- set_effective_uid(0);
- }
-
- ret = kill(pid, SIGUSR1);
-
- if (euid != 0) {
- /* Go back to who we were. */
- int saved_errno = errno;
- restore_re_uid_fromroot();
- errno = saved_errno;
- }
-
- if (ret == 0) {
- return NT_STATUS_OK;
- }
-
- /*
- * Something has gone wrong
- */
-
- DEBUG(2,("message to process %d failed - %s\n", (int)pid,
- strerror(errno)));
-
- /*
- * No call to map_nt_error_from_unix -- don't want to link in
- * errormap.o into lots of utils.
- */
-
- if (errno == ESRCH) return NT_STATUS_INVALID_HANDLE;
- if (errno == EINVAL) return NT_STATUS_INVALID_PARAMETER;
- if (errno == EPERM) return NT_STATUS_ACCESS_DENIED;
- return NT_STATUS_UNSUCCESSFUL;
-}
-
-/****************************************************************************
- Send a message to a particular pid.
-****************************************************************************/
-
-static NTSTATUS messaging_tdb_send(struct messaging_context *msg_ctx,
- struct server_id pid, int msg_type,
- const DATA_BLOB *data,
- struct messaging_backend *backend)
-{
- struct messaging_tdb_context *ctx = talloc_get_type(backend->private_data,
- struct messaging_tdb_context);
- struct messaging_array *msg_array;
- struct messaging_rec *rec;
- NTSTATUS status;
- TDB_DATA key;
- struct tdb_wrap *tdb = ctx->tdb;
- TALLOC_CTX *frame = talloc_stackframe();
-
- /* NULL pointer means implicit length zero. */
- if (!data->data) {
- SMB_ASSERT(data->length == 0);
- }
-
- /*
- * Doing kill with a non-positive pid causes messages to be
- * sent to places we don't want.
- */
-
- SMB_ASSERT(procid_to_pid(&pid) > 0);
-
- key = message_key_pid(frame, pid);
-
- if (tdb_chainlock(tdb->tdb, key) != 0) {
- TALLOC_FREE(frame);
- return NT_STATUS_LOCK_NOT_GRANTED;
- }
-
- status = messaging_tdb_fetch(tdb->tdb, key, frame, &msg_array);
-
- if (!NT_STATUS_IS_OK(status)) {
- goto done;
- }
-
- if ((msg_type & MSG_FLAG_LOWPRIORITY)
- && (msg_array->num_messages > 1000)) {
- DEBUG(5, ("Dropping message for PID %s\n",
- procid_str_static(&pid)));
- status = NT_STATUS_INSUFFICIENT_RESOURCES;
- goto done;
- }
-
- if (!(rec = talloc_realloc(frame, msg_array->messages,
- struct messaging_rec,
- msg_array->num_messages+1))) {
- status = NT_STATUS_NO_MEMORY;
- goto done;
- }
-
- rec[msg_array->num_messages].msg_version = MESSAGE_VERSION;
- rec[msg_array->num_messages].msg_type = msg_type & MSG_TYPE_MASK;
- rec[msg_array->num_messages].dest = pid;
- rec[msg_array->num_messages].src = msg_ctx->id;
- rec[msg_array->num_messages].buf = *data;
-
- msg_array->messages = rec;
- msg_array->num_messages += 1;
-
- status = messaging_tdb_store(tdb->tdb, key, msg_array);
-
- if (!NT_STATUS_IS_OK(status)) {
- goto done;
- }
-
- status = message_notify(pid);
-
- if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_HANDLE)) {
- DEBUG(2, ("pid %s doesn't exist - deleting messages record\n",
- procid_str_static(&pid)));
- tdb_delete(tdb->tdb, message_key_pid(frame, pid));
- }
-
- done:
- tdb_chainunlock(tdb->tdb, key);
- TALLOC_FREE(frame);
- return status;
-}
-
-/****************************************************************************
- Retrieve all messages for a process.
-****************************************************************************/
-
-static NTSTATUS retrieve_all_messages(TDB_CONTEXT *msg_tdb,
- struct server_id id,
- TALLOC_CTX *mem_ctx,
- struct messaging_array **presult)
-{
- struct messaging_array *result;
- TDB_DATA key = message_key_pid(mem_ctx, id);
- NTSTATUS status;
-
- if (tdb_chainlock(msg_tdb, key) != 0) {
- TALLOC_FREE(key.dptr);
- return NT_STATUS_LOCK_NOT_GRANTED;
- }
-
- status = messaging_tdb_fetch(msg_tdb, key, mem_ctx, &result);
-
- /*
- * We delete the record here, tdb_set_max_dead keeps it around
- */
- tdb_delete(msg_tdb, key);
- tdb_chainunlock(msg_tdb, key);
-
- if (NT_STATUS_IS_OK(status)) {
- *presult = result;
- }
-
- TALLOC_FREE(key.dptr);
-
- return status;
-}
-
-/****************************************************************************
- Receive and dispatch any messages pending for this process.
- JRA changed Dec 13 2006. Only one message handler now permitted per type.
- *NOTE*: Dispatch functions must be able to cope with incoming
- messages on an *odd* byte boundary.
-****************************************************************************/
-
-static void message_dispatch(struct messaging_context *msg_ctx)
-{
- struct messaging_tdb_context *ctx = talloc_get_type(msg_ctx->local->private_data,
- struct messaging_tdb_context);
- struct messaging_array *msg_array = NULL;
- struct tdb_wrap *tdb = ctx->tdb;
- NTSTATUS status;
- uint32 i;
-
- if (ctx->received_messages == 0) {
- return;
- }
-
- DEBUG(10, ("message_dispatch: received_messages = %d\n",
- ctx->received_messages));
-
- status = retrieve_all_messages(tdb->tdb, msg_ctx->id, NULL, &msg_array);
- if (!NT_STATUS_IS_OK(status)) {
- DEBUG(0, ("message_dispatch: failed to retrieve messages: %s\n",
- nt_errstr(status)));
- return;
- }
-
- ctx->received_messages = 0;
-
- for (i=0; i<msg_array->num_messages; i++) {
- messaging_dispatch_rec(msg_ctx, &msg_array->messages[i]);
- }
-
- TALLOC_FREE(msg_array);
-}
-
-/** @} **/
git.samba.org / obnox / samba / samba-obnox.git / commitdiff