initial checkout from wrc

1 files changed, 66 insertions, 0 deletions

diff --git a/user/progH.c b/user/progH.c
new file mode 100644
index 0000000..386144d
--- /dev/null
+++ b/user/progH.c
@@ -0,0 +1,66 @@
+#include <common.h>
+
+/**
+** User function H:  exit, fork, exec, sleep, write
+**
+** Prints its ID, then spawns 'n' children; exits before they terminate.
+**
+** Invoked as:  userH  x  n
+**	 where x is the ID character
+**		   n is the number of children to spawn
+*/
+
+USERMAIN( main ) {
+	int32_t ret = 0;  // return value
+	int count = 5;	  // child count
+	char ch = 'h';	  // default character to print
+	char buf[128];
+	int whom;
+
+	// process the argument(s)
+	switch( argc ) {
+	case 3:	count = str2int( argv[2], 10 );
+			// FALL THROUGH
+	case 2:	ch = argv[1][0];
+			break;
+	default:
+			sprint( buf, "userH: argc %d, args: ", argc );
+			cwrites( buf );
+			for( int i = 0; i <= argc; ++i ) {
+				sprint( buf, " %s", argv[argc] ? argv[argc] : "(null)" );
+				cwrites( buf );
+			}
+			cwrites( "\n" );
+	}
+
+	// announce our presence
+	swritech( ch );
+
+	// we spawn user Z and then exit before it can terminate
+	// userZ 'Z' 10
+
+	char *argsz[] = { "userZ", "Z", "10", NULL };
+
+	for( int i = 0; i < count; ++i ) {
+
+		// spawn a child
+		whom = spawn( ProgZ, argsz );
+
+		// our exit status is the number of failed spawn() calls
+		if( whom < 0 ) {
+			sprint( buf, "!! %c spawn() failed, returned %d\n", ch, whom );
+			cwrites( buf );
+			ret += 1;
+		}
+	}
+
+	// yield the CPU so that our child(ren) can run
+	sleep( 0 );
+
+	// announce our departure
+	swritech( ch );
+
+	exit( ret );
+
+	return( 42 );  // shut the compiler up!
+}