From 5f4719da21f06b58694d52d354f5fda431ff8543 Mon Sep 17 00:00:00 2001 From: Gabriel Schneider Date: Thu, 27 Aug 2026 15:32:02 -0300 Subject: acmefs: a pane's terminal gets pty/data, pty/ctl and pty/status Step 3 of the 9P chain (docs/9p.typ 12.3, docs/registry.typ 9P-8). Nothing here is about 9P: it lands in the FUSE-served tree and any later transport inherits it. A script could write into a terminal that already existed and read its rendered scrollback. It could not START one, RESIZE one or SIGNAL one. Two of those were already effects the core emits, so `exec` and `winsize` are existing capabilities acquiring a name; only `sig` is new, and it brings the one new host method, `push_pty_signal`. pty/ctl winsize | sig INT|TERM|HUP|QUIT|KILL | exec one verb per line, validate-all then apply-all, EINVAL applies nothing -- `writeCtl`'s shape and `writeCtl`'s reason pty/status cols, rows, tty-taken as three %11d fields pty/data write is input to the process; read is the RAW output stream, gated on a reader count so a pane nobody reads costs one branch A pane that is not a terminal has no pty/ at all: the lookup is ENOENT and readdir does not list it. `PaneFile` is an enum(u4) and this takes it from 11 values to 15. ONE REMAINS. That is also why pty/ is a DIRECTORY and not three more flat names -- a subdirectory costs one value and buys its own namespace, so `ctl` and `data` did not have to be renamed. Two things the core does not know, and which are therefore not invented: a child's EXIT STATUS (a shell's death is `Event.eof`, which removes the pane, so there is no directory left to read it in) and RAW/COOKED (the core never sets a termios; the mode belongs to the program on the far side). Verified live against a daemon: pty/ appears only on the terminal pane; a `winsize 0 24` and a `sig SIGINT` are refused; a bad verb beside a good one applies neither; `echo pty-works` written to pty/data runs in the shell and its output reaches the body; and a blocking read of pty/data returns the raw stream, OSC 133 marks and all. fs-bench unchanged and still zero allocations. --- src/detached/server.zig | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) (limited to 'src/detached/server.zig') diff --git a/src/detached/server.zig b/src/detached/server.zig index 9a8dc24f..d8373149 100644 --- a/src/detached/server.zig +++ b/src/detached/server.zig @@ -590,14 +590,14 @@ pub const Session = struct { return @ptrCast(@alignCast(ctx.?)); } - /// Seventeen methods, and NOT the fullest host in the tree — that claim + /// Eighteen methods, and NOT the fullest host in the tree — that claim /// stood here, was believed, and was copied into docs/detached.md before an - /// audit counted the others. The tty and SDL shells fill NINETEEN each - /// (everything but `pull_gpio_toggle` and `push_detach`) and macOS fourteen, + /// audit counted the others. The tty and SDL shells fill TWENTY each + /// (everything but `pull_gpio_toggle` and `push_detach`) and macOS fifteen, /// so this host is the only one that implements `push_detach` and otherwise /// the least complete of the three desktop hosts. What is true is narrower /// and is the point anyway: it performs every MACHINE-LOCAL effect there is, - /// and the four of host.zig's twenty-one it leaves null are null because + /// and the four of host.zig's twenty-two it leaves null are null because /// there is nothing here for them to do. Two of those four are real losses a /// person can notice — no `pull_lsp` and no `pull_pipe`, because both want /// the worker pool this deliberately single-threaded loop does not have. The @@ -619,6 +619,7 @@ pub const Session = struct { .push_spawn = spawn, .push_pty_write = ptyWrite, .push_pty_resize = ptyResize, + .push_pty_signal = ptySignal, .pull_tty_taken = ttyTaken, .push_write_file = writeFile, .push_write_dump = writeDump, @@ -771,6 +772,18 @@ pub const Session = struct { _ = posix.system.ioctl(fd, TIOCSWINSZ, @intFromPtr(&ws)); } + /// `pty/ctl`'s `sig` — and the host where it matters most, because these + /// shells outlive every frontend: a script that signals a build in a + /// detached session is signalling a process nobody has a terminal on. + /// `fd < 0` is a pane with no shell, the same silence `ptyWrite` gives it. + fn ptySignal(ctx: ?*anyopaque, pane: u8, sig: pardes.PtySignal) void { + const s = of(ctx); + if (pane >= s.ptys.len) return; + const pt = s.ptys[pane]; + if (pt.fd < 0) return; + look.signalTty(pt.pid, pt.fd, sig); + } + /// Is this pane's tty still the prompt we forked, or has a program taken it? /// /// Answerable at all only because the pty is HERE. While a pane's shell -- cgit v1.3