Commit 758a137

Eric Bower  ·  2026-04-24 16:08:27 -0400 EDT
parent 5ebf61b 
refactor(run): check pty foreground process to detect shell

This removes the need to provide the `--fish` flag at all for `zmx run` commands.
4 files changed,  +76, -33
M src/cross.zig
M src/main.zig
M test/session.bats
M test/test_helper.bash
M src/cross.zig
+59, -0
......@@ -1,8 +1,11 @@
11 const builtin = @import("builtin");
2+const std = @import("std");
3+const posix = std.posix;
24
35 pub const c = switch (builtin.os.tag) {
46 .macos => @cImport({
57 @cInclude("sys/ioctl.h"); // ioctl and constants
8+ @cInclude("sys/sysctl.h"); // sysctl for process name lookup
69 @cInclude("termios.h");
710 @cInclude("stdlib.h");
811 @cInclude("unistd.h");
......@@ -28,3 +31,59 @@ pub const forkpty = if (builtin.os.tag == .macos)
2831 }.forkpty
2932 else
3033 c.forkpty;
34+
35+/// Returns the basename of the foreground process running on the given PTY fd.
36+/// Writes into `buf` and returns a slice of it, or null on failure.
37+pub fn getForegroundProcessName(pty_fd: i32, buf: []u8) ?[]const u8 {
38+ const pgid = c.tcgetpgrp(pty_fd);
39+ if (pgid <= 0) return null;
40+
41+ switch (builtin.os.tag) {
42+ .macos => {
43+ // Use KERN_PROC_PGRP to find the process in the foreground group.
44+ // We walk the process list and find the first process whose pgid matches.
45+ var mib = [_]c_int{ c.CTL_KERN, c.KERN_PROC, c.KERN_PROC_PGRP, @intCast(pgid) };
46+ var size: usize = 0;
47+ if (c.sysctl(&mib, mib.len, null, &size, null, 0) != 0) return null;
48+ if (size == 0) return null;
49+
50+ // kinfo_proc is large; allocate on heap to avoid blowing the stack
51+ const kinfo_size = @sizeOf(c.struct_kinfo_proc);
52+ const count = size / kinfo_size;
53+ if (count == 0) return null;
54+
55+ // Use a stack buffer for small lists (usually 1-3 procs), heap otherwise.
56+ var stack_buf: [8 * @sizeOf(c.struct_kinfo_proc)]u8 align(@alignOf(c.struct_kinfo_proc)) = undefined;
57+ const heap_needed = size > stack_buf.len;
58+ const proc_buf: []u8 = if (heap_needed)
59+ std.heap.c_allocator.alloc(u8, size) catch return null
60+ else
61+ stack_buf[0..size];
62+ defer if (heap_needed) std.heap.c_allocator.free(proc_buf);
63+
64+ if (c.sysctl(&mib, mib.len, proc_buf.ptr, &size, null, 0) != 0) return null;
65+
66+ const procs: []c.struct_kinfo_proc = @alignCast(std.mem.bytesAsSlice(c.struct_kinfo_proc, proc_buf[0..size]));
67+ if (procs.len == 0) return null;
68+
69+ // p_comm is a null-terminated fixed-length field
70+ const comm: [*:0]const u8 = @ptrCast(&procs[0].kp_proc.p_comm);
71+ const name = std.mem.sliceTo(comm, 0);
72+ const copy_len = @min(name.len, buf.len);
73+ @memcpy(buf[0..copy_len], name[0..copy_len]);
74+ return buf[0..copy_len];
75+ },
76+ .linux => {
77+ // /proc/<pid>/comm contains just the process name + newline
78+ var path_buf: [64]u8 = undefined;
79+ const path = std.fmt.bufPrint(&path_buf, "/proc/{d}/comm", .{pgid}) catch return null;
80+ const file = std.fs.openFileAbsolute(path, .{}) catch return null;
81+ defer file.close();
82+ const n = file.read(buf) catch return null;
83+ // strip trailing newline
84+ const end = if (n > 0 and buf[n - 1] == '\n') n - 1 else n;
85+ return buf[0..end];
86+ },
87+ else => return null,
88+ }
89+}
M src/main.zig
+15, -25
......@@ -154,15 +154,8 @@ pub fn main() !void {
154154
155155 var cmd_args_raw: std.ArrayList([]const u8) = .empty;
156156 defer cmd_args_raw.deinit(alloc);
157- var shell_basename: []const u8 = "bash";
158157 var detached = false;
159158 while (args.next()) |arg| {
160- // Because fish tracks exit code status via $status instead of $? we need some
161- // way to figure out what shell is being used inside the session.
162- if (std.mem.startsWith(u8, arg, "--fish")) {
163- shell_basename = "fish";
164- continue;
165- }
166159 if (std.mem.startsWith(u8, arg, "-d")) {
167160 detached = true;
168161 continue;
......@@ -195,7 +188,7 @@ pub fn main() !void {
195188 error.OutOfMemory => return err,
196189 };
197190 std.log.info("socket path={s}", .{daemon.socket_path});
198- return run(&daemon, detached, shell_basename, cmd_args_raw.items);
191+ return run(&daemon, detached, cmd_args_raw.items);
199192 } else if (std.mem.eql(u8, cmd, "send") or std.mem.eql(u8, cmd, "s")) {
200193 const session_name = args.next() orelse "";
201194 if (session_name.len == 0) return error.SessionNameRequired;
......@@ -551,6 +544,7 @@ const Daemon = struct {
551544 task_exit_code: ?u8 = null, // null = running or n/a, set when task completes
552545 task_ended_at: ?u64 = null, // timestamp when task exited
553546 is_fish: bool = false, // true if session shell is fish (affects exit code variable)
547+ pty_fd: i32 = -1, // set by daemonLoop so handleRun can probe the foreground process
554548 pty_write_buf: std.ArrayList(u8) = .empty,
555549
556550 const EnsureSessionResult = struct {
......@@ -1101,9 +1095,15 @@ const Daemon = struct {
11011095
11021096 if (payload.len == 0) return;
11031097
1104- // First byte indicates shell type (0=bash/zsh, 1=fish)
1105- self.is_fish = payload[0] == 1;
1106- const cmd = payload[1..];
1098+ // Auto-detect the foreground process on the PTY to determine shell type.
1099+ if (self.pty_fd >= 0) {
1100+ var name_buf: [64]u8 = undefined;
1101+ if (cross.getForegroundProcessName(self.pty_fd, &name_buf)) |name| {
1102+ self.is_fish = std.mem.eql(u8, name, "fish");
1103+ std.log.debug("foreground process={s} is_fish={}", .{ name, self.is_fish });
1104+ }
1105+ }
1106+ const cmd = payload;
11071107
11081108 // Daemon appends the task marker so the client never injects
11091109 // shell-specific syntax, keeping Ctrl-C recovery clean.
......@@ -1221,7 +1221,7 @@ fn help() !void {
12211221 \\
12221222 \\Commands:
12231223 \\ [a]ttach <name> [command...] Attach to session, creating if needed
1224- \\ [r]un <name> [-d] [--fish] [command...] Send command without attaching
1224+ \\ [r]un <name> [-d] [command...] Send command without attaching
12251225 \\ [s]end <name> <text...> Send raw input to session PTY
12261226 \\ [p]rint <name> <text...> Inject text into session display
12271227 \\ [wr]ite <name> <file_path> Write stdin to file_path through the session
......@@ -1255,8 +1255,6 @@ fn help() !void {
12551255 \\ Commands run sequentially: do not send multiple in parallel.
12561256 \\ Avoid interactive programs (pagers, editors, prompts): they hang.
12571257 \\
1258- \\ `--fish` is required when the session runs fish shell.
1259- \\
12601258 \\ If the command hangs, send Ctrl+C to recover:
12611259 \\ zmx run <session> $(printf '\x03')
12621260 \\
......@@ -1268,7 +1266,6 @@ fn help() !void {
12681266 \\
12691267 \\ Examples:
12701268 \\ zmx run dev ls
1271- \\ zmx run dev --fish ls src
12721269 \\ zmx run dev zig build
12731270 \\ zmx run dev grep -r TODO src
12741271 \\ zmx run dev git -c core.pager=cat diff
......@@ -2029,7 +2026,7 @@ fn send(cfg: *Cfg, session_name: []const u8, socket_path: []const u8, text_parts
20292026 };
20302027 }
20312028
2032-fn run(daemon: *Daemon, detached: bool, shell_basename: []const u8, command_args: [][]const u8) !void {
2029+fn run(daemon: *Daemon, detached: bool, command_args: [][]const u8) !void {
20332030 const alloc = daemon.alloc;
20342031 var buf: [4096]u8 = undefined;
20352032 var w = std.fs.File.stdout().writer(&buf);
......@@ -2046,17 +2043,10 @@ fn run(daemon: *Daemon, detached: bool, shell_basename: []const u8, command_args
20462043 try w.interface.flush();
20472044 }
20482045
2049- // Prefix byte tells the daemon which shell syntax to use for the
2050- // task-completion marker (0 = bash/zsh $?, 1 = fish $status).
2051- // The daemon appends the marker itself so the client never injects
2052- // shell-specific text -- keeping recovery (Ctrl-C) clean.
2053- const is_fish: u8 = if (std.mem.eql(u8, shell_basename, "fish")) 1 else 0;
2054-
20552046 if (command_args.len > 0) {
20562047 var cmd_list = std.ArrayList(u8).empty;
20572048 defer cmd_list.deinit(alloc);
20582049
2059- try cmd_list.append(alloc, is_fish);
20602050 for (command_args, 0..) |arg, i| {
20612051 if (i > 0) try cmd_list.append(alloc, ' ');
20622052 if (util.shellNeedsQuoting(arg)) {
......@@ -2082,7 +2072,6 @@ fn run(daemon: *Daemon, detached: bool, shell_basename: []const u8, command_args
20822072 var stdin_buf = try std.ArrayList(u8).initCapacity(alloc, 4096);
20832073 defer stdin_buf.deinit(alloc);
20842074
2085- try stdin_buf.append(alloc, is_fish);
20862075 while (true) {
20872076 var tmp: [4096]u8 = undefined;
20882077 const n = posix.read(stdin_fd, &tmp) catch |err| {
......@@ -2093,7 +2082,7 @@ fn run(daemon: *Daemon, detached: bool, shell_basename: []const u8, command_args
20932082 try stdin_buf.appendSlice(alloc, tmp[0..n]);
20942083 }
20952084
2096- if (stdin_buf.items.len > 1) {
2085+ if (stdin_buf.items.len > 0) {
20972086 // Normalize any trailing newline to CR so readline (raw mode)
20982087 // accepts each line.
20992088 if (stdin_buf.items[stdin_buf.items.len - 1] == '\n') {
......@@ -2316,6 +2305,7 @@ fn clientLoop(client_sock_fd: i32) !ClientResult {
23162305 /// clients. It uses poll() as its non-blocking mechanism.
23172306 fn daemonLoop(daemon: *Daemon, server_sock_fd: i32, pty_fd: i32) !void {
23182307 std.log.info("daemon started session={s} pty_fd={d}", .{ daemon.session_name, pty_fd });
2308+ daemon.pty_fd = pty_fd;
23192309 setupSigtermHandler();
23202310 var poll_fds = try std.ArrayList(posix.pollfd).initCapacity(daemon.alloc, 8);
23212311 defer poll_fds.deinit(daemon.alloc);
M test/session.bats
+2, -2
......@@ -208,7 +208,7 @@ load test_helper
208208 # ============================================================================
209209
210210 @test "wait: returns after session command completes" {
211- "$ZMX" run test-wait -d $SHELL_FLAG echo done
211+ "$ZMX" run test-wait -d echo done
212212 wait_for_session test-wait
213213 sleep 1 # give the command time to finish
214214
......@@ -239,7 +239,7 @@ load test_helper
239239 # ============================================================================
240240
241241 @test "print: text appears in history" {
242- "$ZMX" run test-print-hist -d $SHELL_FLAG echo ready
242+ "$ZMX" run test-print-hist -d echo ready
243243 wait_for_session test-print-hist
244244 sleep 0.3
245245
M test/test_helper.bash
+0, -6
......@@ -9,12 +9,6 @@ setup() {
99 fi
1010 ZMX="$REPO_DIR/zig-out/bin/zmx"
1111
12- # Detect shell so task-completion markers use the right syntax
13- case "$(basename "$SHELL")" in
14- fish) SHELL_FLAG="--fish" ;;
15- *) SHELL_FLAG="" ;;
16- esac
17-
1812 # Isolate socket dir so tests don't interfere with real sessions or each other
1913 export ZMX_DIR="$BATS_TEST_TMPDIR/zmx-sockets"
2014 mkdir -p "$ZMX_DIR"