ww: enforce internal package visibility

lib/os/os.ww

@@ -46,6 +46,7 @@ type nr = enum i64 {
 	RMDIR       = 84,
 	UNLINK      = 87,
 	SYMLINK     = 88,
+	READLINK    = 89,
 	SETPGID     = 109,
 	GETDENTS64  = 217,
 	NEWFSTATAT  = 262,
@@ -132,7 +133,7 @@ export def SFD_NONBLOCK: i32 = O_NONBLOCK;
 export def SFD_CLOEXEC: i32 = O_CLOEXEC;
 
 fn kpath(p: str) *u8 = {
-	if (p.len + 1 >= PATH_MAX) { return nil: *u8; };	// ENAMETOOLONG
+	if (p.len + 1 > PATH_MAX) { return nil: *u8; };	// ENAMETOOLONG
 	let i: i32 = 0;
 	for (i < p.len) { pathbuf[i] = p[i]; i += 1; };
 	pathbuf[p.len] = 0u8;
@@ -347,7 +348,7 @@ export fn rmdir(path: str) i32 = {
 export fn rename(oldpath: str, newpath: str) i32 = {
 	let p: *u8 = kpath(oldpath);
 	if (p == nil: *u8) { return -36i32; };
-	if (newpath.len + 1 >= PATH_MAX) { return -36i32; };
+	if (newpath.len + 1 > PATH_MAX) { return -36i32; };
 	let i: i32 = 0;
 	for (i < newpath.len) { pathbuf2[i] = newpath[i]; i += 1; };
 	pathbuf2[newpath.len] = 0u8;
@@ -364,13 +365,21 @@ export fn rename(oldpath: str, newpath: str) i32 = {
 export fn symlink(target: str, path: str) i32 = {
 	let p: *u8 = kpath(target);
 	if (p == nil: *u8) { return -36i32; };
-	if (path.len + 1 >= PATH_MAX) { return -36i32; };
+	if (path.len + 1 > PATH_MAX) { return -36i32; };
 	let i: i32 = 0;
 	for (i < path.len) { pathbuf2[i] = path[i]; i += 1; };
 	pathbuf2[path.len] = 0u8;
 	return syscall2(nr.SYMLINK, p: i64, (&pathbuf2[0]): i64): i32;
 };
 
+// readlink — read a symlink target without appending NUL. The caller owns the
+// buffer and uses the returned byte count, matching readlink(2).
+export fn readlink(path: str, buf: *u8, n: u64) i64 = {
+	let p: *u8 = kpath(path);
+	if (p == nil: *u8) { return -36i64; };
+	return syscall3(nr.READLINK, p: i64, buf: i64, n: i64);
+};
+
 // mkdirs — recursive mkdir. Creates `path` and any non-existent
 // parent directories with the given mode. EEXIST is silently
 // accepted (matches Hare's `errors::exists` skip in os::mkdirs);

lib/os/stat_test.ww

@@ -157,6 +157,25 @@ fn istype(m: os.mode, t: os.mode) bool = {
 	rmtree(&t);
 };
 
+@test fn test_readlink_verbatim() void = {
+	let t: tree;
+	mktree(&t);
+	let buf: [16]u8;
+	let i: i32 = 0;
+	for (i < 16) { buf[i] = 90u8; i += 1; };	// 'Z'
+	let n: i64 = os.readlink(t.symlink, &buf[0], 16u64);
+	assert(!(n != 9i64));
+	let want: str = "./regfile";
+	i = 0;
+	for (i < want.len) {
+		assert(!(buf[i] != want[i]));
+		i += 1;
+	};
+	let ni: i32 = n: i32;
+	assert(!(buf[ni] != 90u8));
+	rmtree(&t);
+};
+
 @test fn test_fstat_regfile() void = {
 	let t: tree;
 	mktree(&t);
@@ -196,7 +215,7 @@ fn istype(m: os.mode, t: os.mode) bool = {
 };
 
 // kpath copies into a single [PATH_MAX]u8 buffer and reserves one byte
-// for the NUL terminator (`p.len + 1 >= PATH_MAX` → reject). The
+// for the NUL terminator (`p.len + 1 > PATH_MAX` → reject). The
 // rejection surfaces as `oserror = -36` (ENAMETOOLONG) on (... |
 // oserror)-returning wrappers, and as `false` on [[os.exists]]
 // (Hare's os::exists doc: "true if a node exists at the given path,