From e565ee563f422e97a9603c90ed9b53cc64494bf0 Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Fri, 20 Jan 2017 12:23:54 -0800
Subject: [PATCH] SCP: Assure that all SCP produced debug output always lands
 in the debug file

The fprintf substitute function Fprintf can call tmxr_linemsgvf which may
internally produce debug output thus producing an infinite recursion.

All writes to the debug file are now done by explicit calls to fwrite() OR the
Fprintf socket destination is saved and cleared during all calls to fprintf.
---
 scp.c | 61 +++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 41 insertions(+), 20 deletions(-)

diff --git a/scp.c b/scp.c
index 6ee92171..e3d05199 100644
--- a/scp.c
+++ b/scp.c
@@ -6569,10 +6569,15 @@ printf ("\n");
 if (unechoed_cmdline && (r >= SCPE_BASE) && (r != SCPE_STEP) && (r != SCPE_STOP) && (r != SCPE_EXPECT))
     sim_printf("%s> %s\n", do_position(), unechoed_cmdline);
 fprint_stopped (stdout, r);                         /* print msg */
-if (sim_log && (sim_log != stdout))                 /* log if enabled */
+if ((!sim_oline) && ((sim_log && (sim_log != stdout))))/* log if enabled */
     fprint_stopped (sim_log, r);
-if (sim_deb && (sim_deb != stdout) && (sim_deb != sim_log))/* debug if enabled */
+if (sim_deb && (sim_deb != stdout) && (sim_deb != sim_log)) {/* debug if enabled */
+    TMLN *saved_oline = sim_oline;
+
+    sim_oline = NULL;                               /* avoid potential debug to active socket */
     fprint_stopped (sim_deb, r);
+    sim_oline = saved_oline;                        /* restore original socket */
+    }
 }
 
 /* Common setup for RUN or BOOT */
@@ -8801,19 +8806,25 @@ t_stat sim_print_val (t_value val, uint32 radix,
     uint32 width, uint32 format)
 {
 char dbuf[MAX_WIDTH + 1];
+t_stat stat = SCPE_OK;
 
 if (width > MAX_WIDTH)
     width = MAX_WIDTH;
 sprint_val (dbuf, val, radix, width, format);
 if (fputs (dbuf, stdout) == EOF)
-    return SCPE_IOERR;
-if (sim_log && (sim_log != stdout))
+    stat = SCPE_IOERR;
+if ((!sim_oline) && ((sim_log && (sim_log != stdout))))
     if (fputs (dbuf, sim_log) == EOF)
-        return SCPE_IOERR;
-if (sim_deb && (sim_deb != stdout))
+        stat = SCPE_IOERR;
+if (sim_deb && (sim_deb != stdout)) {
+    TMLN *saved_oline = sim_oline;
+
+    sim_oline = NULL;                               /* avoid potential debug to active socket */
     if (fputs (dbuf, sim_deb) == EOF)
-        return SCPE_IOERR;
-return SCPE_OK;
+        stat = SCPE_IOERR;
+    sim_oline = saved_oline;                        /* restore original socket */
+    }
+return stat;
 }
 
 const char *sim_fmt_secs (double seconds)
@@ -10631,8 +10642,8 @@ else
     fprintf (stdout, "%s", buf);
 if ((!sim_oline) && (sim_log && (sim_log != stdout)))
     fprintf (sim_log, "%s", buf);
-if ((!sim_oline) && (sim_deb && (sim_deb != stdout) && (sim_deb != sim_log)))
-    fprintf (sim_deb, "%s", buf);
+if (sim_deb && (sim_deb != stdout) && (sim_deb != sim_log))
+    fwrite (buf, 1, strlen (buf), sim_deb);
 
 if (buf != stackbuf)
     free (buf);
@@ -10686,8 +10697,13 @@ if (sim_do_ocptr[sim_do_depth]) {
     if (!sim_do_echo && !sim_quiet && !inhibit_message)
         sim_printf("%s> %s\n", do_position(), sim_do_ocptr[sim_do_depth]);
     else {
-        if (sim_deb)                        /* Always put context in debug output */
+        if (sim_deb) {                      /* Always put context in debug output */
+            TMLN *saved_oline = sim_oline;
+
+            sim_oline = NULL;               /* avoid potential debug to active socket */
             fprintf (sim_deb, "%s> %s\n", do_position(), sim_do_ocptr[sim_do_depth]);
+            sim_oline = saved_oline;        /* restore original socket */
+            }
         }
     }
 if (sim_is_running && !inhibit_message) {
@@ -10708,8 +10724,14 @@ else {
     }
 if ((!sim_oline) && (sim_log && (sim_log != stdout) && !inhibit_message))
     fprintf (sim_log, "%s", buf);
-if ((!sim_oline) && (sim_deb && (((sim_deb != stdout) && (sim_deb != sim_log)) || inhibit_message)))/* Always display messages in debug output */
+/* Always display messages in debug output */
+if (sim_deb && (((sim_deb != stdout) && (sim_deb != sim_log)) || inhibit_message)) {
+    TMLN *saved_oline = sim_oline;
+
+    sim_oline = NULL;                           /* avoid potential debug to active socket */
     fprintf (sim_deb, "%s", buf);
+    sim_oline = saved_oline;                    /* restore original socket */
+    }
 
 if (buf != stackbuf)
     free (buf);
@@ -10775,10 +10797,10 @@ if (sim_deb && dptr && (dptr->dctrl & dbits)) {
         if ('\n' == buf[i]) {
             if (i >= j) {
                 if ((i != j) || (i == 0)) {
-                    if (debug_unterm)
-                        fprintf (sim_deb, "%.*s\r\n", i-j, &buf[j]);
-                    else                                /* print prefix when required */
-                        fprintf (sim_deb, "%s%.*s\r\n", debug_prefix, i-j, &buf[j]);
+                    if (!debug_unterm)                  /* print prefix when required */
+                        fwrite (debug_prefix, 1, strlen (debug_prefix), sim_deb);
+                    fwrite (&buf[j], 1, i-j, sim_deb);
+                    fwrite ("\r\n", 1, 2, sim_deb);
                     }
                 debug_unterm = 0;
                 }
@@ -10786,10 +10808,9 @@ if (sim_deb && dptr && (dptr->dctrl & dbits)) {
             }
         }
     if (i > j) {
-        if (debug_unterm)
-            fprintf (sim_deb, "%.*s", i-j, &buf[j]);
-        else                                        /* print prefix when required */
-            fprintf (sim_deb, "%s%.*s", debug_prefix, i-j, &buf[j]);
+        if (!debug_unterm)                          /* print prefix when required */
+            fwrite (debug_prefix, 1, strlen (debug_prefix), sim_deb);
+        fwrite (&buf[j], 1, i-j, sim_deb);
         }
 
 /* Set unterminated flag for next time */