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Add sesexec discover module

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The module is a dummy to be filled in later

Other structural changes to sesexec:-
1) A failure of sesman needs to be detected and handled without
   causing sesexec to exit
2) If sesexec exits, the session can never be rediscovered. sesexec must
   be robust enough to stay up for the lifetime of the session so that
   the discovery function always works.
3) There is a mechanism for sesexec to terminate the session, but it
   doesn't work, as SIGCHLD is not processed while we are waiting for
   the session to finish. This needs fixing.
This commit is contained in:
matt335672
2024-12-06 12:12:24 +00:00
parent eadbb6a190
commit bee806d3af
5 changed files with 309 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files
sesman/sesexec/Makefile.am
+2
View File
@@ -29,6 +29,8 @@ xrdp_sesexec_SOURCES = \
env.h \
login_info.c \
login_info.h \
sesexec_discover.c \
sesexec_discover.h \
sessionrecord.c \
sessionrecord.h \
xauth.c \
sesman/sesexec/eicp_server.c
+60 -29
View File
@@ -37,6 +37,7 @@
#include "ercp.h"
#include "scp.h"
#include "sesexec.h"
#include "sesexec_discover.h"
#include "session.h"
/******************************************************************************/
@@ -98,12 +99,13 @@ handle_create_session_request(struct trans *self)
{
int scp_fd;
struct session_parameters sp = {0};
int rv;
int status;
rv = eicp_get_create_session_request(self, &scp_fd, &sp.display,
&sp.type, &sp.width, &sp.height,
&sp.bpp, &sp.shell, &sp.directory);
if (rv == 0)
status = eicp_get_create_session_request(
self, &scp_fd, &sp.display,
&sp.type, &sp.width, &sp.height,
&sp.bpp, &sp.shell, &sp.directory);
if (status == 0)
{
// Need to talk to the SCP client
struct trans *scp_trans;
@@ -113,7 +115,7 @@ handle_create_session_request(struct trans *self)
{
LOG(LOG_LEVEL_ERROR, "Can't create SCP trans");
g_file_close(scp_fd);
rv = 1;
status = 1;
}
else
{
@@ -134,39 +136,68 @@ handle_create_session_request(struct trans *self)
scp_status = session_start(g_login_info, &sp, &g_session_data);
}
// Return the status to the SCP client
rv = scp_send_create_session_response(scp_trans, scp_status,
sp.display, &sp.guid);
trans_delete(scp_trans);
// Further comms from sesexec is sent over the ERCP protocol
// Further comms to sesman is sent over the ERCP protocol
ercp_trans_from_eicp_trans(self,
sesexec_ercp_data_in,
(void *)self);
if (scp_status == E_SCP_SCREATE_OK)
if (scp_status != E_SCP_SCREATE_OK)
{
rv = ercp_send_session_announce_event(
self,
sp.display,
g_login_info->uid,
sp.type,
sp.width,
sp.height,
sp.bpp,
&sp.guid,
g_login_info->ip_addr,
session_get_start_time(g_session_data));
// Tell sesman the session hasn't started
(void)ercp_send_session_finished_event(self);
}
else
else if ((status = ercp_send_session_announce_event(
self,
sp.display,
g_login_info->uid,
sp.type,
sp.width,
sp.height,
sp.bpp,
&sp.guid,
g_login_info->ip_addr,
session_get_start_time(g_session_data))) != 0)
{
rv = ercp_send_session_finished_event(self);
sesexec_terminate_main_loop(1);
// We failed to tell sesman about the new session. This
// probably means sesman has exited in the time between
// asking us to start a session, and our reply. This
// could be many seconds, and a new sesman may well
// have started.
// If we enable the restart functionality at
// this point, we have a race condition that could
// result in a session which sesman doesn't know
// about. The simplest thing to do in this rare situation
// is to abort the session - the user can create a
// new one
LOG(LOG_LEVEL_ERROR,
"sesman appears to have failed - stopping session");
scp_status = E_SCP_SCREATE_GENERAL_ERROR;
}
else if ((status = sesexec_discover_enable()) != 0)
{
// Equally regrettable - we can't make the session
// discoverable, so we'll stop it. We can tell sesman
// about this one however.
LOG(LOG_LEVEL_ERROR,
"unable to make session discoverable"
" - stopping session");
(void)ercp_send_session_finished_event(self);
scp_status = E_SCP_SCREATE_GENERAL_ERROR;
}
}
// Return the status to the SCP client.
(void)scp_send_create_session_response(scp_trans, scp_status,
sp.display, &sp.guid);
trans_delete(scp_trans);
}
}
return rv;
if (status != 0)
{
// Kill sesexec, and any active session
sesexec_terminate_main_loop(status);
}
return 0;
}
/******************************************************************************/
sesman/sesexec/sesexec.c
+107 -18
View File
@@ -38,6 +38,7 @@
#include "ercp_server.h"
#include "login_info.h"
#include "sesexec.h"
#include "sesexec_discover.h"
#include "sesman_config.h"
#include "log.h"
#include "os_calls.h"
@@ -209,8 +210,12 @@ sesexec_is_term(void)
void
sesexec_terminate_main_loop(int status)
{
g_terminate_loop = 1;
g_terminate_status = status;
// Only take the first request to terminate the loop
if (!g_terminate_loop)
{
g_terminate_loop = 1;
g_terminate_status = status;
}
}
/******************************************************************************/
@@ -227,6 +232,45 @@ process_sigchld_event(void)
}
}
/******************************************************************************/
static void
sesexec_terminate_session_and_wait(void)
{
session_send_term(g_session_data);
do
{
g_sleep(1000);
// Process SIGCHLD events while waiting for the session
// to exit.
if (g_is_wait_obj_set(g_sigchld_event))
{
g_reset_wait_obj(g_sigchld_event);
process_sigchld_event();
}
}
while (session_active(g_session_data));
}
/******************************************************************************/
static void
sesexec_main_loop_cleanup(void)
{
login_info_free(g_login_info);
/* This session is no longer discoverable */
sesexec_discover_disable();
/* Don't allow sesexec to terminate with an active
session, as we can't connect to such a session */
if (session_active(g_session_data))
{
LOG(LOG_LEVEL_INFO,
"Stopping session on xrdp-sesexec exit");
sesexec_terminate_session_and_wait();
}
session_data_free(g_session_data);
}
/******************************************************************************/
/**
*
@@ -238,7 +282,8 @@ sesexec_main_loop(void)
{
int error = 0;
int robjs_count;
intptr_t robjs[32];
#define MAX_ROBJS 32
intptr_t robjs[MAX_ROBJS];
g_terminate_loop = 0;
g_terminate_status = 0;
@@ -250,11 +295,25 @@ sesexec_main_loop(void)
robjs[robjs_count++] = g_term_event;
robjs[robjs_count++] = g_sigchld_event;
error = trans_get_wait_objs(g_ecp_trans, robjs, &robjs_count);
// ECP transport may be null if sesman has gone away
if (g_ecp_trans != NULL)
{
error = trans_get_wait_objs(g_ecp_trans, robjs, &robjs_count);
if (error != 0)
{
LOG(LOG_LEVEL_ERROR, "sesexec_main_loop: "
"trans_get_wait_objs(ECP) failed");
sesexec_terminate_main_loop(error);
continue;
}
}
// Add any objects from the discover module
error = sesexec_discover_get_wait_objs(robjs, &robjs_count, MAX_ROBJS);
if (error != 0)
{
LOG(LOG_LEVEL_ERROR, "sesexec_main_loop: "
"trans_get_wait_objs(ECP) failed");
"sesexec_discover_get_wait_objs() failed");
sesexec_terminate_main_loop(error);
continue;
}
@@ -273,21 +332,17 @@ sesexec_main_loop(void)
g_reset_wait_obj(g_term_event);
if (session_active(g_session_data))
{
// Ask the active session to terminate
LOG(LOG_LEVEL_INFO, "sesexec_main_loop: "
"sesexec asked to terminate. "
"Terminating active session");
session_send_term(g_session_data);
"sesexec asked to terminate with active session.");
}
else
{
// Terminate immediately
LOG(LOG_LEVEL_INFO, "sesexec_main_loop: "
"sesexec asked to terminate. "
"No session is active");
sesexec_terminate_main_loop(0);
continue;
}
sesexec_terminate_main_loop(0);
continue;
}
if (g_is_wait_obj_set(g_sigchld_event)) /* SIGCHLD */
@@ -302,7 +357,10 @@ sesexec_main_loop(void)
{
// We've finished the session. Tell sesman and
// finish up.
(void)ercp_send_session_finished_event(g_ecp_trans);
if (g_ecp_trans != NULL)
{
(void)ercp_send_session_finished_event(g_ecp_trans);
}
session_data_free(g_session_data);
g_session_data = NULL;
@@ -311,19 +369,51 @@ sesexec_main_loop(void)
}
}
error = trans_check_wait_objs(g_ecp_trans);
if (g_ecp_trans != NULL)
{
error = trans_check_wait_objs(g_ecp_trans);
if (error != 0)
{
if (g_ecp_trans->status != TRANS_STATUS_UP &&
session_active(g_session_data))
{
// sesman has gone away. We have an active session
// to keep track of, so sesman can pick it up when it
// restarts
LOG(LOG_LEVEL_INFO, "sesexec_main_loop: "
"sesman has exited");
trans_delete(g_ecp_trans);
g_ecp_trans = NULL;
}
else
{
// A callback has failed, or sesman has gone away and
// we have no active session
LOG(LOG_LEVEL_ERROR, "sesexec_main_loop: "
"trans_check_wait_objs failed for ECP transport");
sesexec_terminate_main_loop(error);
}
continue;
}
}
error = sesexec_discover_check_wait_objs();
if (error != 0)
{
LOG(LOG_LEVEL_ERROR, "sesexec_main_loop: "
"trans_check_wait_objs failed for ECP transport");
"sesexec_discover_check_wait_objs failed");
sesexec_terminate_main_loop(error);
continue;
}
}
login_info_free(g_login_info);
/* close sesman communications immediately */
trans_delete(g_ecp_trans);
g_ecp_trans = NULL;
return g_terminate_status;
#undef MAX_ROBJS
}
/******************************************************************************/
@@ -483,9 +573,8 @@ main(int argc, char **argv)
/* start program main loop */
LOG(LOG_LEVEL_INFO, "starting xrdp-sesexec with pid %d", g_pid);
error = sesexec_main_loop();
trans_delete(g_ecp_trans);
sesexec_main_loop_cleanup();
}
g_delete_wait_obj(g_term_event);
}
config_free(g_cfg);
sesman/sesexec/sesexec_discover.c
+63
View File
@@ -0,0 +1,63 @@
/**
* xrdp: A Remote Desktop Protocol server.
*
* Copyright (C) Jay Sorg 2004-2024
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
*
* @file sesexec_discover.c
* @brief Declare functionality associated with sesman restart support
* @author Matt Burt
*
*/
#if defined(HAVE_CONFIG_H)
#include <config_ac.h>
#endif
#include "sesexec_discover.h"
/******************************************************************************/
int
sesexec_discover_enable(void)
{
return 0;
}
/******************************************************************************/
int
sesexec_discover_disable(void)
{
return 0;
}
/******************************************************************************/
int
sesexec_discover_get_wait_objs(intptr_t robjs[], int *robjs_count,
int max_count)
{
return 0;
}
/******************************************************************************/
int
sesexec_discover_check_wait_objs(void)
{
return 0;
}
sesman/sesexec/sesexec_discover.h
+77
View File
@@ -0,0 +1,77 @@
/**
* xrdp: A Remote Desktop Protocol server.
*
* Copyright (C) Jay Sorg 2004-2024
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
*
* @file sesexec_discover.h
* @brief Declare functionality associated with sesman restart support
* for sesexec
*
* @author Matt Burt
*
*/
#ifndef SESEXEC_DISCOVER_H
#define SESEXEC_DISCOVER_H
#include <stdint.h>
/**
* Start the listening object used when sesman restarts
*
* @return != 0 for error
*/
int
sesexec_discover_enable(void);
/**
* Stop the listening object used when sesman restarts, and deallocate all
* module resources.
*
* @return != 0 for error
*/
int
sesexec_discover_disable(void);
/**
* Add any file descriptors in use by the module to an array
*
* @param robjs Array to add fds to
* @param[in,out] robjs_count Index where elements are to be added
* @param max_count Max value of robjs_count
* @return != 0 for error
*
* This function can be called before sesexec_discover_enable(),
* in which case it does nothing.
*/
int
sesexec_discover_get_wait_objs(intptr_t robjs[], int *robjs_count,
int max_count);
/**
* Check any file descriptors in use by the module for actionable events
* @return != 0 for error
*
* This function can be called before sesexec_discover_enable(),
* in which case it does nothing.
*/
int
sesexec_discover_check_wait_objs(void);
#endif // SESEXEC_DISCOVER_H