SCP: Add support to uniquely identify SIGTERM in do procedures

As discussed in #681

scp.c

@@ -600,6 +600,7 @@ static double sim_time;
 static uint32 sim_rtime;
 static int32 noqueue_time;
 volatile t_bool stop_cpu = FALSE;
+volatile t_bool sigterm_received = FALSE;
 static unsigned int sim_stop_sleep_ms = 250;
 static char **sim_argv;
 static int sim_exit_status = EXIT_SUCCESS;              /* optionally set by EXIT command */
@@ -757,6 +758,7 @@ const struct scp_error {
          {"AMBREG",  "Ambiguous register name"},
          {"REMOTE",  "remote console command"},
          {"INVEXPR", "invalid expression"},
+         {"SIGTERM", "SIGTERM received"},
     };
 
 const size_t size_map[] = { sizeof (int8),
@@ -1811,7 +1813,7 @@ static const char simh_help[] =
       "++NOPARAM, ALATT, TIMER, SIGERR, TTYERR, SUB, NOFNC, UDIS,\n"
       "++NORO, INVSW, MISVAL, 2FARG, 2MARG, NXDEV, NXUN, NXREG,\n"
       "++NXPAR, NEST, IERR, MTRLNT, LOST, TTMO, STALL, AFAIL,\n"
-      "++AMBREG\n\n"
+      "++AMBREG, SIGTERM\n\n"
       " These values can be indicated by name or by their internal\n"
       " numeric value (not recommended).\n"
       /***************** 80 character line width template *************************/
@@ -1831,6 +1833,15 @@ static const char simh_help[] =
       "+ON CONTROL_C trap handler.\n"
       " Note 2: The ON CONTROL_C trapping is not affected by the SET ON and\n"
       "+SET NOON commands.\n"
+      "3SIGTERM Trapping\n"
+      " A special ON trap is available to describe action(s) to be taken\n"
+      " when a SIGTERM (or a Windows Shutdown) signal is delivered during\n"
+      " simulator instruction execution.  After a SIGTERM has been delivered\n"
+      " to a simulator process, instruction execution will stop and control\n"
+      " will return to either the invoking do command procedure with a SIGTERM\n"
+      " status (and thus take SIGTERM ON condition) or if execution was\n"
+      " explicitly started from a sim> prompt, the program will exit\n"
+
 #define HLP_PROCEED     "*Commands Executing_Command_Files PROCEED"
 #define HLP_IGNORE      "*Commands Executing_Command_Files PROCEED"
        /***************** 80 character line width template *************************/
@@ -2667,7 +2678,8 @@ stat = SCPE_BARE_STATUS(stat);                          /* remove possible flag
 while (stat != SCPE_EXIT) {                             /* in case exit */
     if (stop_cpu) {                                     /* SIGINT happened? */
         stop_cpu = FALSE;
-        if (!sim_ttisatty()) {
+        if ((!sim_ttisatty()) || 
+            sigterm_received) {
             stat = SCPE_EXIT;
             break;
             }
@@ -8004,6 +8016,10 @@ do {
         sim_activate (&sim_step_unit, sim_step);
     } while (1);
 
+if ((SCPE_BARE_STATUS(r) == SCPE_STOP) &&
+    sigterm_received)
+    r = SCPE_SIGTERM;
+
 if ((SCPE_BARE_STATUS(r) == SCPE_STOP) &&               /* WRU exit from sim_instr() */
     (sim_on_actions[sim_do_depth][SCPE_STOP] == NULL) &&/* without a handler for a STOP condition */
     (sim_on_actions[sim_do_depth][0] == NULL))
@@ -8155,6 +8171,8 @@ return sim_cancel (&sim_step_unit);
 void int_handler (int sig)
 {
 stop_cpu = TRUE;
+if (sig == SIGTERM)
+    sigterm_received = TRUE;
 }
 
 /* Examine/deposit commands

sim_console.c

@@ -3388,6 +3388,8 @@ static DWORD saved_output_mode;
          console terminal is a useful character to be passed to the 
          simulator.  This code does nothing to disable or affect that. */
 
+#include <signal.h>
+
 static BOOL WINAPI
 ControlHandler(DWORD dwCtrlType)
     {
@@ -3398,7 +3400,7 @@ ControlHandler(DWORD dwCtrlType)
         {
         case CTRL_BREAK_EVENT:      // Use CTRL-Break or CTRL-C to simulate 
         case CTRL_C_EVENT:          // SERVICE_CONTROL_STOP in debug mode
-            int_handler(0);
+            int_handler(SIGINT);
             return TRUE;
         case CTRL_CLOSE_EVENT:      // Window is Closing
         case CTRL_LOGOFF_EVENT:     // User is logging off
@@ -3406,7 +3408,7 @@ ControlHandler(DWORD dwCtrlType)
                 return TRUE;        // Not our User, so ignore
             /* fall through */
         case CTRL_SHUTDOWN_EVENT:   // System is shutting down
-            int_handler(0);
+            int_handler(SIGTERM);
             return TRUE;
         }
     return FALSE;

sim_defs.h

@@ -415,8 +415,9 @@ typedef uint32          t_addr;
 #define SCPE_AMBREG     (SCPE_BASE + 45)                /* ambiguous register */
 #define SCPE_REMOTE     (SCPE_BASE + 46)                /* remote console command */
 #define SCPE_INVEXPR    (SCPE_BASE + 47)                /* invalid expression */
+#define SCPE_SIGTERM    (SCPE_BASE + 48)                /* SIGTERM has been received */
 
-#define SCPE_MAX_ERR    (SCPE_BASE + 47)                /* Maximum SCPE Error Value */
+#define SCPE_MAX_ERR    (SCPE_BASE + 48)                /* Maximum SCPE Error Value */
 #define SCPE_KFLAG      0x10000000                      /* tti data flag */
 #define SCPE_BREAK      0x20000000                      /* tti break flag */
 #define SCPE_NOMESSAGE  0x40000000                      /* message display supression flag */