1 files changed, 61 insertions, 0 deletions
diff --git a/appl/cmd/ps.b b/appl/cmd/ps.b
new file mode 100644
index 00000000..06c51a2f
--- /dev/null
+++ b/appl/cmd/ps.b
@@ -0,0 +1,61 @@
+implement Ps;
+
+include "sys.m";
+include "draw.m";
+
+FD, Dir: import Sys;
+Context: import Draw;
+
+Ps: module
+{
+	init:	fn(ctxt: ref Context, argv: list of string);
+};
+
+sys: Sys;
+stderr: ref FD;
+
+init(nil: ref Context, nil: list of string)
+{
+	sys = load Sys Sys->PATH;
+
+	stderr = sys->fildes(2);
+
+	sys->pctl(Sys->FORKNS, nil);
+	if(sys->chdir("/prog") < 0){
+		sys->fprint(stderr, "ps: can't chdir to /prog: %r\n");
+		raise "fail:no /prog";
+	}
+	fd := sys->open(".", sys->OREAD);
+	if(fd == nil) {
+		sys->fprint(stderr, "ps: cannot open /prog: %r\n");
+		raise "fail:no /prog";
+	}
+
+	for(;;) {
+		(n, d) := sys->dirread(fd);
+		if(n <= 0){
+			if(n < 0) {
+				sys->fprint(stderr, "ps: error reading /prog: %r\n");
+				raise "fail:error on /prog";
+			}
+			break;
+		}
+		for(i := 0; i < n; i++)
+			if(d[i].name[0] >= '0' && d[i].name[0] <= '9')
+				ps(int d[i].name);		
+	}
+}
+
+ps(pid: int)
+{
+	proc := string pid+"/status";
+	fd := sys->open(proc, sys->OREAD);
+	if(fd == nil) {	# process must have died
+		# sys->fprint(stderr, "ps: /prog/%s: %r\n", proc);
+		return;
+	}
+	buf := array[128] of byte;
+	n := sys->read(fd, buf, len buf);
+	if(n > 0)
+		sys->print("%s\n", string buf[0:n]);
+}