From d324e795edea6f4d17a4947ece1f823245717031 Mon Sep 17 00:00:00 2001
From: CrazyEttin <>
Date: Sun, 2 Oct 2022 14:00:11 +0300
Subject: [PATCH] Make the emulated modem recognise dropped connection and act
 accordingly

---
 emulator.pas | 53 ++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 6 deletions(-)

diff --git a/emulator.pas b/emulator.pas
index 2eb4e3c..8014710 100644
--- a/emulator.pas
+++ b/emulator.pas
@@ -11,7 +11,7 @@ program Emulator;
 {$define status}
 {$endif}
 
-uses SysUtils, Crt{$ifdef modem}, Sockets{$endif}{$ifdef status}, BaseUnix{$endif};
+uses SysUtils, Crt{$ifdef modem}, BaseUnix, Sockets{$endif}{$ifdef status}{$ifndef modem}, BaseUnix{$endif}{$endif};
 
 type
     {$ifdef tape}
@@ -80,11 +80,17 @@ var
     ModemState: file of Connection; //File storing the state of the modem
     ServerSocket, ListenSocket, ClientSocket, ClientAddrSize: longint; //Server socket
     ServerAddr, ClientAddr: TInetSockAddr; //Server address
+    SigPipeHandler: pSigActionRec; //SIGPIPE handler
     {$endif}
     {$ifdef status}
     FileDescs: TFDset; //File descriptor set
     {$endif}
 
+//Ignore signal
+procedure DoSig (Sig: cint); cdecl;
+begin
+end;
+
 //Terminal output
 procedure Output;
 begin
@@ -314,8 +320,21 @@ begin
         //Connect
         CallServer;
         //Recieve
-        if Calling then fpRecv (ServerSocket, @B, 1, 0)
-        else if Answering then fpRecv (ClientSocket, @B, 1, 0)
+        if Calling then begin
+            if fpRecv (ServerSocket, @B, 1, 0) <> 1 then begin
+                B := 0;
+                CloseSocket (ServerSocket);
+                Calling := false;
+            end;
+        end
+        else if Answering then begin
+            if fpRecv (ClientSocket, @B, 1, 0) <> 1 then begin
+                B := 0;
+                CloseSocket (ClientSocket);
+                CloseSocket (ListenSocket);
+                Answering := false;
+            end;
+        end
         else B := 0;
     end
     {$endif}
@@ -343,7 +362,7 @@ begin
         {$ifdef modem}
         //Connect
         CallServer;
-        //Check the connection
+        //Check connection status
         if Calling then begin
             fpfd_zero (FileDescs);
             fpfd_set (ServerSocket, FileDescs);
@@ -710,8 +729,19 @@ begin
         //Connect
         CallServer;
         //Send
-        if Calling then fpSend (ServerSocket, @B, 1, 0)
-        else if Answering then fpSend (ClientSocket, @B, 1, 0);
+        if Calling then begin
+            if fpSend (ServerSocket, @B, 1, 0) <> 1 then begin
+                CloseSocket (ServerSocket);
+                Calling := false;
+            end;
+        end
+        else if Answering then begin
+            if fpSend (ClientSocket, @B, 1, 0) <> 1 then begin
+                CloseSocket (ClientSocket);
+                CloseSocket (ListenSocket);
+                Answering := false;
+            end;
+        end;
     end
     {$endif}
     //Regular store
@@ -767,6 +797,17 @@ begin
     {$ifdef modem}
     //Initialise the modem
     Calling := false;
+    Answering := false;
+    //Initialise the SIGPIPE handler
+    new (SigPipeHandler);
+    SigPipeHandler^.sa_Handler := SigActionHandler (@DoSig);
+    fillchar (SigPipeHandler^.Sa_Mask, sizeof (SigPipeHandler^.sa_mask), #0);
+    SigPipeHandler^.Sa_Flags := 0;
+    SigPipeHandler^.Sa_Restorer := nil;
+    try
+        fpSigAction (SigPipe, SigPipeHandler, nil);
+    except
+    end;
     {$endif}
 
     //Check the arguments