20060303a

1 files changed, 60 insertions, 0 deletions

diff --git a/appl/cmd/runas.b b/appl/cmd/runas.b
new file mode 100644
index 00000000..d0112396
--- /dev/null
+++ b/appl/cmd/runas.b
@@ -0,0 +1,60 @@
+implement Runas;
+
+include "sys.m";
+include "draw.m";
+include "sh.m";
+
+sys: Sys;
+sh: Sh;
+
+Context: import sh;
+
+Runas: module {
+	init: fn(nil: ref Draw->Context, argv: list of string);
+};
+
+init(drawctxt: ref Draw->Context, argv: list of string)
+{
+	sys = load Sys Sys->PATH;
+	sh = load Sh Sh->PATH;
+	if (sh == nil)
+		badmodule(Sh->PATH);
+
+	if (len argv < 3)
+		usage();
+
+	argv = tl argv;
+	user := hd argv;
+	argv = tl argv;
+
+	fd := sys->open("/dev/user", Sys->OWRITE);
+	if (fd == nil)
+		error(sys->sprint("cannot open /dev/user: %r"));
+	u := array of byte user;
+	if (sys->write(fd, u, len u) != len u)
+		error(sys->sprint("cannot set user: %r"));
+	sh->run(drawctxt, argv);
+}
+
+badmodule(p: string)
+{
+	sys->fprint(stderr(), "runas: cannot load %s: %r\n", p);
+	raise "fail:bad module";
+}
+
+stderr(): ref Sys->FD
+{
+	return sys->fildes(2);
+}
+
+usage()
+{
+	sys->fprint(stderr(), "usage: runas user cmd [args...]\n");
+	raise "fail:usage";
+}
+
+error(e: string)
+{
+	sys->fprint(stderr(), "runas: %s\n", e);
+	raise "fail:error";
+}
\ No newline at end of file