1 files changed, 125 insertions, 0 deletions
diff --git a/appl/cmd/chmod.b b/appl/cmd/chmod.b
new file mode 100644
index 00000000..de7ecf2c
--- /dev/null
+++ b/appl/cmd/chmod.b
@@ -0,0 +1,125 @@
+implement Chmod;
+
+include "sys.m";
+include "draw.m";
+include "string.m";
+
+Chmod: module
+{
+	init:	fn(ctxt: ref Draw->Context, argv: list of string);
+};
+
+sys:	Sys;
+stderr: ref Sys->FD;
+
+str:	String;
+
+User:	con 8r700;
+Group:	con 8r070;
+Other:	con 8r007;
+All:	con User | Group | Other;
+
+Read:	con 8r444;
+Write:	con 8r222;
+Exec:	con 8r111;
+
+usage()
+{
+	sys->fprint(stderr, "usage: chmod [8r]777 file ... or chmod [augo][+-=][rwxal] file ...\n");
+	raise "fail:usage";
+}
+
+init(nil: ref Draw->Context, argv: list of string)
+{
+	sys = load Sys Sys->PATH;
+	stderr = sys->fildes(2);
+
+	str = load String String->PATH;
+	if(str == nil){
+		sys->fprint(stderr, "chmod: cannot load %s: %r\n", String->PATH);
+		raise "fail:bad module";
+	}
+
+	if(len argv < 3)
+		usage();
+	argv = tl argv;
+	m := hd argv;
+	argv = tl argv;
+
+	mask := All;
+	if (str->prefix("8r", m))
+		m = m[2:];
+	(mode, s) := str->toint(m, 8);
+	if(s != "" || m == ""){
+		ok := 0;
+		(ok, mask, mode) = parsemode(m);
+		if(!ok){
+			sys->fprint(stderr, "chmod: bad mode '%s'\n", m);
+			usage();
+		}
+	}
+	ndir := sys->nulldir;
+	for(; argv != nil; argv = tl argv){
+		f := hd argv;
+		(ok, dir) := sys->stat(f);
+		if(ok < 0){
+			sys->fprint(stderr, "chmod: cannot stat %s: %r\n", f);
+			continue;
+		}
+		ndir.mode = (dir.mode & ~mask) | (mode & mask);
+		if(sys->wstat(f, ndir) < 0)
+			sys->fprint(stderr, "chmod: cannot wstat %s: %r\n", f);
+	}
+}
+
+parsemode(spec: string): (int, int, int)
+{
+	mask := Sys->DMAPPEND | Sys->DMEXCL | Sys->DMTMP;
+loop:	for(i := 0; i < len spec; i++){
+		case spec[i] {
+		'u' =>
+			mask |= User;
+		'g' =>
+			mask |= Group;
+		'o' =>
+			mask |= Other;
+		'a' =>
+			mask |= All;
+		* =>
+			break loop;
+		}
+	}
+	if(i == len spec)
+		return (0, 0, 0);
+	if(i == 0)
+		mask |= All;
+
+	op := spec[i++];
+	if(op != '+' && op != '-' && op != '=')
+		return (0, 0, 0);
+
+	mode := 0;
+	for(; i < len spec; i++){
+		case spec[i]{
+		'r' =>
+			mode |= Read;
+		'w' =>
+			mode |= Write;
+		'x' =>
+			mode |= Exec;
+		'a' =>
+			mode |= Sys->DMAPPEND;
+		'l' =>
+			mode |= Sys->DMEXCL;
+		't' =>
+			mode |= Sys->DMTMP;
+		* =>
+			return (0, 0, 0);
+		}
+	}
+	if(op == '+' || op == '-')
+		mask &= mode;
+	if(op == '-')
+		mode = ~mode;
+	return (1, mask, mode);
+}