removed requirement for absolute path to command

README.md

@@ -27,13 +27,13 @@ This allows you to get updates later easily as follows:
 There is a file "captured_data" in the repo, which you can use to test the tek4010 emulator.
 "captured_data" was produced in 2.11 BSD using my program "dodekagon". Type
 
-	./tek4010 /bin/cat captured_data -noexit
+	./tek4010 cat captured_data -noexit
 
 If you want to test text output, type for example
 
-	./tek4010 /usr/bin/head -n 32 tek4010.c -noexit
+	./tek4010 head -n 32 tek4010.c -noexit
 
-Don't forget the absolute path to "cat" or "head" and the LAST argument "-noexit", which tells
+Don't forget the LAST argument "-noexit", which tells
 tek4010 to stay alive after cat has finished so that you have a chance to look at the output.
 By the way, the "-noexit" as the LAST argument might also be helpful if you want to
 experiment with other commands. Let me know if you find anything which works and makes sense.
@@ -54,7 +54,8 @@ or
 This can either be a real historical computer, or a virtual system using simh such
 as the PiDP-11.
 
-First, you need to login remotely from your client machine into your historical system, using
+First, you need to test the remote login from your client machine into your historical
+system, using
 
 	rsh -l user_name system
 or
@@ -69,13 +70,12 @@ or
 
 If this works properly, you can use the tek4010 emulator. Call it as follows:
 
-	./tek4010 /usr/bin/rsh -l user_name system
+	./tek4010 rsh -l user_name system
 or
-	./tek4010 /usr/bin/telnet system
+	./tek4010 telnet system
 
-In the current alpha-testing version, there are very few useful error messages if this does
-not work. If the terminal window is closed right away, there is a problem with your rsh or
-telnet call or you forgot to use the absolute path for rsh or telnet.
+If the terminal window is closed right away, there is a problem with your rsh or
+telnet call.
 
 The following keys are not transmitted to the Unix system, but are executed locally
 in the terminal emulator and clear the persistent screen:
@@ -112,7 +112,7 @@ the Raspberry Pi. You cannot use telnet here.
 
 Now start tek4010 as follows:
 
-	./tek4010 /usr/bin/rsh -l pi localhost
+	./tek4010 rsh -l pi localhost
 
 This should give you a login prompt into your Raspberry Pi. If not, test the rsh call first.
 

main.c

@@ -47,7 +47,6 @@ extern FILE *putKeys;
 static cairo_surface_t *global_surface, *global_surface2;
 static int global_firstcall;
 
-int global_noexit;
 int globalClearPersistent;
 
 static void do_drawing(cairo_t *, GtkWidget *);
@@ -141,14 +140,7 @@ int main (int argc, char *argv[])
 {
 	GtkWidget *darea;
 	GtkWidget *window;
-        
-        if (strcmp(argv[argc-1],"-noexit") == 0) {
-                global_noexit = 1;
-                argc--;
-        }
-        else
-                global_noexit = 0;
-  
+          
 	gtk_init(&argc, &argv);
 	
 	global_firstcall = TRUE;

main.h

@@ -3,7 +3,8 @@
 
 void tek4010_init(int argc, char* argv[]);
 void tek4010_draw(cairo_t *cr, cairo_t *cr2, int width, int height, int first);
-int tek4010_on_timer_event();
-int tek4010_clicked(int button, int x, int y);
+int  tek4010_on_timer_event();
+int  tek4010_clicked(int button, int x, int y);
 void tek4010_quit();
 
+

tek4010.c

@@ -6,13 +6,14 @@
  * Copyright 2016,2019  rricharz
  * 
  */
-
+ 
 #define MEM 128
 
 #define TODO 6          // for speed reasons, draw multiple objects until screen updates
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h> 
 #include <termios.h>
 #include <sys/ioctl.h>
 #include <sys/types.h>
@@ -25,7 +26,7 @@
 
 extern void gtk_main_quit();
 extern int globalClearPersistent;
-extern int global_noexit;
+int noexit;
 
 /* not yet used, for dsrk mode
 int memx1[MEM], memy1[MEM], memx2[MEM], memy2[MEM];
@@ -82,10 +83,40 @@ void tek4010_init(int argc, char* argv[])
 // put any code here to initialize the tek4010
 {
         char *argv2[10];
+        size_t bufsize = 127;
         if ((argc<2) || (argc>9)) {
                 printf("Error:number of arguments\n");
                 exit(1);
         }
+        
+        if (strcmp(argv[argc-1],"-noexit") == 0) {
+                noexit = 1;
+                argc--;
+        }
+        else
+                noexit = 0;
+        
+        // expand argv[1] to full path and check, whether it exists
+        char *str = (char *) malloc(bufsize * sizeof(char));
+        if (str == NULL) {
+               printf("Cannot allocate memory for absolute path\n");
+               exit(1);
+        }
+        strcpy(str,"which ");
+        strcat(str, argv[1]);
+        FILE *fullPath = popen(str,"r");
+        if (fullPath) {
+                getline(&str, &bufsize,fullPath);
+                // remove the endline character
+                str[strlen(str)-1] = 0;
+                argv[1] = str;
+                pclose(fullPath);
+        }
+        else {
+                printf("Cannot find command %s\n", argv[1]);
+                exit(1);
+        }
+                
         hDotsPerChar  = WINDOW_WIDTH / 74;
         vDotsPerChar  = WINDOW_HEIGHT / 35;
         globalClearPersistent = 1;
@@ -127,10 +158,13 @@ void tek4010_init(int argc, char* argv[])
                 
                 // run rsh in the child process
                 execv(argv2[0],argv2+1);
-                exit(1);
+                free(str);
+                exit(0);
         }
                 
         // parent process
+        
+        free(str);
                 
         close(getDataPipe[1]); // not used
         close(putKeysPipe[0]); // not used
@@ -412,9 +446,10 @@ void tek4010_draw(cairo_t *cr, cairo_t *cr2, int width, int height, int first)
         // is child process still running?
         
         int status;
-        if ((! global_noexit) && (waitpid(-1, &status, WNOHANG))) {    // Is child process terminated?
+        if ((! noexit) && (waitpid(-1, &status, WNOHANG))) {    // Is child process terminated?
                 tek4010_quit();
                 gtk_main_quit();
+                printf("Child process has been terminated\n");
                 exit(0);
         }
 }