Fill in discovery module

Add functionality to sesexec discovery module to enable sesman
restarts.

sesman/sesexec/sesexec_discover.c

@@ -28,20 +28,130 @@
 #include <config_ac.h>
 #endif
 
+#include <stdio.h>
+
 #include "sesexec_discover.h"
+#include "trans.h"
+#include "sesexec.h"
+#include "session.h"
+#include "sesman_config.h"
+#include "os_calls.h"
+#include "ercp.h"
+#include "login_info.h"
+
+/*
+ * Module-scope globals
+ */
+static struct trans *g_discover_trans = NULL;
+
+/*****************************************************************************/
+static int
+discover_trans_conn_in(struct trans *trans, struct trans *new_trans)
+{
+    const struct session_parameters *sp;
+    int rv = 0;
+
+    if (trans == NULL || new_trans == NULL || trans != g_discover_trans)
+    {
+        return 1;
+    }
+
+    LOG_DEVEL(LOG_LEVEL_DEBUG, "discover_trans_conn_in:");
+
+    if (sesexec_is_ecp_active())
+    {
+        int pid = 0;
+        (void)g_sck_get_peer_cred(new_trans->sck, &pid, 0, 0);
+
+        LOG(LOG_LEVEL_WARNING,
+            "Connection attempt to sesexec PID %d from PID %d"
+            " while ECP is still active",
+            g_pid, pid);
+
+        trans_delete(new_trans);
+    }
+    else if ((sp = session_get_parameters(g_session_data)) == NULL)
+    {
+        // If we haven't got session parameters, we shouldn't be here
+        LOG(LOG_LEVEL_ERROR, "Bugcheck: Can't get active session params");
+        trans_delete(new_trans);
+        rv = 1;
+    }
+    else
+    {
+        // Reconnect to sesman and tell it about our existing
+        // session
+        ercp_init_trans(new_trans);
+        new_trans->trans_data_in = sesexec_ercp_data_in;
+        new_trans->callback_data = (void *)new_trans;
+
+        // Note, this call makes further privilege checks that may still
+        // fail.  If they do however, we wish to carry on running. These
+        // failed checks will be logged.
+        if (sesexec_set_ecp_transport(new_trans) == 0)
+        {
+            (void)ercp_send_session_announce_event(
+                new_trans,
+                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));
+        }
+    }
+    return rv;
+}
 
 /******************************************************************************/
 int
 sesexec_discover_enable(void)
 {
-    return 0;
+    int rv = 1;
+    if (g_session_data == NULL)
+    {
+        LOG(LOG_LEVEL_ERROR, "Cant enable discovery without an active session");
+    }
+    else if (g_discover_trans != NULL)
+    {
+        LOG(LOG_LEVEL_ERROR, "Logic error: discovery is already active");
+    }
+    else if ((g_discover_trans =
+                  trans_create(TRANS_MODE_UNIX, 8192, 8192)) == NULL)
+    {
+        LOG(LOG_LEVEL_ERROR, "Out of memory enabling discovery");
+    }
+    else
+    {
+        char discover_port[XRDP_SOCKETS_MAXPATH];
+
+        snprintf(discover_port, sizeof(discover_port), "%s.r/%u",
+                 g_cfg->listen_port,
+                 session_get_parameters(g_session_data)->display);
+        g_discover_trans->is_term = sesexec_is_term;
+        g_discover_trans->trans_conn_in = discover_trans_conn_in;
+        if ((rv = trans_listen(g_discover_trans, discover_port)) != 0)
+        {
+            LOG(LOG_LEVEL_ERROR, "Transport error enabling discovery [%s]",
+                g_get_strerror());
+            trans_delete(g_discover_trans);
+            g_discover_trans = NULL;
+        }
+    }
+
+    return rv;
 }
 
 /******************************************************************************/
-
 int
 sesexec_discover_disable(void)
 {
+    trans_delete(g_discover_trans);
+    g_discover_trans = NULL;
+
     return 0;
 }
 
@@ -51,13 +161,28 @@ int
 sesexec_discover_get_wait_objs(intptr_t robjs[], int *robjs_count,
                                int max_count)
 {
-    return 0;
+    int rv;
+    if (g_discover_trans == NULL)
+    {
+        rv = 0;
+    }
+    else if (*robjs_count >= max_count)
+    {
+        rv = 1;
+    }
+    else
+    {
+        rv = trans_get_wait_objs(g_discover_trans, robjs, robjs_count);
+    }
+
+    return rv;
 }
 
 /******************************************************************************/
-
 int
 sesexec_discover_check_wait_objs(void)
 {
-    return 0;
+    return (g_discover_trans == NULL)
+           ? 0
+           : trans_check_wait_objs(g_discover_trans);
 }