Add sesexec_restart module

sesman/sesexec/Makefile.am

@@ -29,6 +29,8 @@ xrdp_sesexec_SOURCES = \
   env.h \
   login_info.c \
   login_info.h \
+  sesexec_restart.c \
+  sesexec_restart.h \
   sessionrecord.c \
   sessionrecord.h \
   xauth.c \

sesman/sesexec/eicp_server.c

@@ -37,6 +37,7 @@
 #include "ercp.h"
 #include "scp.h"
 #include "sesexec.h"
+#include "sesexec_restart.h"
 #include "session.h"
 
 /******************************************************************************/
@@ -146,17 +147,22 @@ handle_create_session_request(struct trans *self)
 
             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));
+                // Now we're in charge of a session, we need to enable
+                // the restart functionality so we can cope if sesman fails
+                if ((rv = sesexec_restart_enable()) == 0)
+                {
+                    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));
+                }
             }
             else
             {

sesman/sesexec/sesexec.c

@@ -38,6 +38,7 @@
 #include "ercp_server.h"
 #include "login_info.h"
 #include "sesexec.h"
+#include "sesexec_restart.h"
 #include "sesman_config.h"
 #include "log.h"
 #include "os_calls.h"
@@ -262,7 +263,8 @@ 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;
@@ -274,11 +276,25 @@ 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 restart module
+        error = sesexec_restart_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_restart_get_wait_objs() failed");
             sesexec_terminate_main_loop(error);
             continue;
         }
@@ -326,7 +342,10 @@ 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;
@@ -335,19 +354,47 @@ 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)
+            {
+                LOG(LOG_LEVEL_ERROR, "sesexec_main_loop: "
+                    "trans_check_wait_objs failed for ECP transport");
+                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
+                    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
+                    sesexec_terminate_main_loop(error);
+                }
+                continue;
+            }
+        }
+
+        error = sesexec_restart_check_wait_objs();
         if (error != 0)
         {
             LOG(LOG_LEVEL_ERROR, "sesexec_main_loop: "
-                "trans_check_wait_objs failed for ECP transport");
+                "sesexec_restart_check_wait_objs failed");
             sesexec_terminate_main_loop(error);
             continue;
         }
+
     }
 
     login_info_free(g_login_info);
 
     return g_terminate_status;
+#undef MAX_ROBJS
 }
 
 /******************************************************************************/
@@ -508,6 +555,7 @@ main(int argc, char **argv)
                 LOG(LOG_LEVEL_INFO, "starting xrdp-sesexec with pid %d", g_pid);
                 error = sesexec_main_loop();
                 trans_delete(g_ecp_trans);
+                sesexec_restart_disable();
             }
 
             g_delete_wait_obj(g_term_event);

sesman/sesexec/sesexec_restart.c

@@ -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 login_info.c
+ * @brief Declare functionality associated with sesman restart support
+ * @author Matt Burt
+ *
+ */
+
+#if defined(HAVE_CONFIG_H)
+#include <config_ac.h>
+#endif
+
+#include "sesexec_restart.h"
+
+/******************************************************************************/
+int
+sesexec_restart_enable(void)
+{
+    return 0;
+}
+
+/******************************************************************************/
+
+int
+sesexec_restart_disable(void)
+{
+    return 0;
+}
+
+/******************************************************************************/
+
+int
+sesexec_restart_get_wait_objs(intptr_t robjs[], int *robjs_count,
+                              int max_count)
+{
+    return 0;
+}
+
+/******************************************************************************/
+
+int
+sesexec_restart_check_wait_objs(void)
+{
+    return 0;
+}

sesman/sesexec/sesexec_restart.h

@@ -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_restart.h
+ * @brief Declare functionality associated with sesman restart support
+ * for sesexec
+ *
+ * @author Matt Burt
+ *
+ */
+
+#ifndef SESEXEC_RESTART_H
+#define SESEXEC_RESTART_H
+
+#include <stdint.h>
+
+/**
+ * Start the listening object used when sesman restarts
+ *
+ * @return != 0 for error
+ */
+int
+sesexec_restart_enable(void);
+
+/**
+ * Stop the listening object used when sesman restarts, and deallocate all
+ * module resources.
+ *
+ * @return != 0 for error
+ */
+int
+sesexec_restart_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_restart_enable(),
+ * in which case it does nothing.
+ */
+int
+sesexec_restart_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_restart_enable(),
+ * in which case it does nothing.
+ */
+int
+sesexec_restart_check_wait_objs(void);
+
+#endif // SESEXEC_RESTART_H