/pager refuses a directory that is not there, ENOENT, and a relative one, EINVAL: no +Pager named into a missing directory, none quietly the session's

`/(/+Pager` was made for a missing absolute directory, and a relative
one fell back to the session's without a word. An empty line still asks
for the session's directory.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 12 insertions, 4 deletions

diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index 1fcd7a6d..1e274e0c 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -647,8 +647,14 @@ pub fn writePager(p: *Pardes, req: Req) Reply {
     var it = Messages.init(p, req.data);
     const line = it.next() orelse "";
     if (it.next() != null) return tree.failText(req.tag, E.INVAL, "pager: one directory a write");
+    const dir = std.mem.trim(u8, line, " \t");
+    // A directory that is there, or none (the session's): never a +Pager
+    // named into one missing, nor a relative one quietly taken for none.
+    if (dir.len > 0 and dir[0] != '/') return refuseQuoting(p, req, "pager: the directory must be absolute", dir);
+    if (comptime pardes.hosted) if (dir.len > 0) if (pardes.filesystem.localPath(dir)) |local| if (!exec_line.isDirectory(local))
+        return tree.failText(req.tag, E.NOENT, std.fmt.bufPrint(&p.fs.ename, "pager: {s}: no such directory", .{dir[0..@min(dir.len, 256)]}) catch "pager: no such directory");
     p.fs.results_len = 0;
-    const id = pardes.panes.Output.openPager(p, p.active, std.mem.trim(u8, line, " \t")) catch |err|
+    const id = pardes.panes.Output.openPager(p, p.active, dir) catch |err|
         return tree.failText(req.tag, if (err == error.NoPaneRoom or err == error.NoPaneSlots) E.NOSPC else E.IO, switch (err) {
             error.NoPaneRoom, error.NoPaneSlots => "pager: no space for a +Pager pane",
             else => "pager: could not make a +Pager pane",
@@ -4011,10 +4017,10 @@ test "pager answers its +Pager on the open that asked, whatever another client e
     const pager = @intFromEnum(tree.TopFile.pager);
     const exec = @intFromEnum(tree.TopFile.exec);
     const asked = call(p, .{ .tag = 1, .op = .open, .node = pager, .omode = 2 }).reply.handle;
-    try testing.expectEqual(Status.ok, call(p, .{ .tag = 2, .op = .write, .node = pager, .handle = asked, .data = "/tmp/pager-race\n" }).reply.status);
+    try testing.expectEqual(Status.ok, call(p, .{ .tag = 2, .op = .write, .node = pager, .handle = asked, .data = "/tmp\n" }).reply.status);
     const paged = for (p.panes) |slot| {
         const pn = slot orelse continue;
-        if (pn.file) |f| if (std.mem.eql(u8, f.path, "/tmp/pager-race/+Pager")) break pn.serial;
+        if (pn.file) |f| if (std.mem.eql(u8, f.path, "/tmp/+Pager")) break pn.serial;
     } else return error.NoPager;
     // Another client execs between the request and its read: a pane of its own.
     const racer = call(p, .{ .tag = 3, .op = .open, .node = exec, .omode = 2 }).reply.handle;
@@ -4025,8 +4031,10 @@ test "pager answers its +Pager on the open that asked, whatever another client e
     // `pardes -` once read, and wrote its text into.
     try testing.expect(!std.mem.eql(u8, want, rd(p, exec, 0, 64).bytes));
     try testing.expectEqualStrings(want, call(p, .{ .tag = 5, .op = .read, .node = pager, .handle = asked, .size = 64 }).bytes);
-    // One directory a write.
+    // One directory a write, absolute, and there.
     try testing.expectEqual(E.INVAL, wr(p, pager, "/a\n/b\n").errno());
+    try testing.expectEqual(E.INVAL, wr(p, pager, "relative\n").errno());
+    try testing.expectEqual(E.NOENT, wr(p, pager, "/tmp/pardes-surely-missing-dir\n").errno());
 }
 
 test "a command pane an exec open was answered is leased to it while it stays open: another client's command gets a pane of its own" {