Speed up --detach

Also DRYer as well as more robust since single instance cleanup, binding
etc. happen in single process.

kittens/panel/main.py

@@ -1,7 +1,6 @@
 #!/usr/bin/env python
 # License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
 
-import os
 import sys
 from collections.abc import Callable
 from contextlib import suppress
@@ -349,14 +348,6 @@ def handle_single_instance_command(boss: BossType, sys_args: Sequence[str], envi
 def main(sys_args: list[str]) -> None:
     global args
     args, items = parse_panel_args(sys_args[1:])
-    talk_fd = -1
-    if args.single_instance:
-        si_data = os.environ.get('KITTY_SI_DATA', '')
-        if si_data:
-            talk_fd = int(si_data)
-    if args.detach:
-        from kitty.utils import detach
-        detach(talk_fd, log_file=args.detached_log or os.devnull)
     sys.argv = ['kitty']
     if args.debug_rendering:
         sys.argv.append('--debug-rendering')

kitty/cli.py

@@ -909,11 +909,14 @@ Change to the specified directory when launching.
 
 --detach
 type=bool-set
-condition=not is_macos
-Detach from the controlling terminal, if any. Not available on macOS. On macOS
+Detach from the controlling terminal, if any. On macOS
 use :code:`open -a kitty.app -n` instead.
 
 
+--detached-log
+Path to a log file to store STDOUT/STDERR when using :option:`--detach`
+
+
 --session
 completion=type:file ext:session relative:conf group:"Session files"
 Path to a file containing the startup :italic:`session` (tabs, windows, layout,

kitty/data-types.c

@@ -66,17 +66,6 @@ process_group_map(PyObject *self UNUSED, PyObject *args UNUSED) {
 }
 #endif
 
-static PyObject*
-redirect_std_streams(PyObject UNUSED *self, PyObject *args, PyObject *kw) {
-    char *in = "", *out = "", *err = "";
-    static const char* kwlist[] = {"stdin", "stdout", "stderr", NULL};
-    if (!PyArg_ParseTupleAndKeywords(args, kw, "|sss", (char**)kwlist, &in, &out, &err)) return NULL;
-    if (in[0] && freopen(in, "r", stdin) == NULL) return PyErr_SetFromErrno(PyExc_OSError);
-    if (out[0] && freopen(out, "a", stdout) == NULL) return PyErr_SetFromErrno(PyExc_OSError);
-    if (out[0] && freopen(err, "a", stderr) == NULL)  return PyErr_SetFromErrno(PyExc_OSError);
-    Py_RETURN_NONE;
-}
-
 static PyObject*
 pybase64_encode(PyObject UNUSED *self, PyObject *const *args, Py_ssize_t nargs) {
     int add_padding = 0;
@@ -664,7 +653,6 @@ static PyMethodDef module_methods[] = {
     {"char_props_for", py_char_props_for, METH_O, ""},
     {"split_into_graphemes", (PyCFunction)split_into_graphemes, METH_O, ""},
     {"thread_write", (PyCFunction)cm_thread_write, METH_VARARGS, ""},
-    {"redirect_std_streams", (PyCFunction)(void (*) (void))(redirect_std_streams), METH_VARARGS | METH_KEYWORDS, NULL},
     {"locale_is_valid", (PyCFunction)locale_is_valid, METH_VARARGS, ""},
     {"shm_open", (PyCFunction)py_shm_open, METH_VARARGS, ""},
     {"shm_unlink", (PyCFunction)py_shm_unlink, METH_VARARGS, ""},

kitty/fast_data_types.pyi

@@ -335,10 +335,6 @@ def log_error_string(s: str) -> None:
     pass
 
 
-def redirect_std_streams(stdin: str = '', stdout: str = '', stderr: str = '') -> None:
-    pass
-
-
 def glfw_get_key_name(key: int, native_key: int) -> Optional[str]:
     pass
 

kitty/launcher/launcher.h

@@ -10,8 +10,8 @@
 #include <stdbool.h>
 
 typedef struct CLIOptions {
-    const char *session, *instance_group;
-    bool single_instance, version_requested, wait_for_single_instance_window_close;
+    const char *session, *instance_group, *detached_log;
+    bool single_instance, version_requested, wait_for_single_instance_window_close, detach;
     int open_url_count; char **open_urls;
 } CLIOptions;
 

kitty/launcher/main.c

@@ -378,6 +378,8 @@ handle_option_value:
                 opts.session = arg;
             } else if (strcmp(current_option_expecting_argument, "instance-group") == 0) {
                 opts.instance_group = arg;
+            } else if (strcmp(current_option_expecting_argument, "detached-log") == 0) {
+                opts.detached_log = arg;
             }
             current_option_expecting_argument[0] = 0;
         } else {
@@ -397,11 +399,14 @@ handle_option_value:
                         opts.single_instance = true;
                     } else if (strcmp(arg+2, "wait-for-single-instance-window-close") == 0) {
                         opts.wait_for_single_instance_window_close = true;
+                    } else if (strcmp(arg+2, "detach") == 0) {
+                        opts.detach = true;
                     } else if (!is_boolean_flag(arg+2)) {
                         strncpy(current_option_expecting_argument, arg+2, sizeof(current_option_expecting_argument)-1);
                     }
                 } else {
                     memcpy(current_option_expecting_argument, arg+2, equal - (arg + 2));
+                    current_option_expecting_argument[equal - (arg + 2)] = 0;
                     arg = equal + 1;
                     goto handle_option_value;
                 }
@@ -432,6 +437,14 @@ handle_option_value:
         }
         exit(0);
     }
+    if (opts.detach) {
+        if (fork() != 0) exit(0);
+        setsid();
+        if (!(opts.session && ((opts.session[0] == '-' && opts.session[1] == 0) || strcmp(opts.session, "/dev/stdin") == 0))) freopen("/dev/null", "r", stdin);
+        if (!opts.detached_log || !opts.detached_log[0]) opts.detached_log = "/dev/null";
+        freopen(opts.detached_log, "ab", stdout);
+        freopen(opts.detached_log, "ab", stderr);
+    }
     unsetenv("KITTY_SI_DATA");
     if (opts.single_instance) {
         char igbuf[256];

kitty/main.py

@@ -56,7 +56,6 @@ from .shaders import CompileError, load_shader_programs
 from .types import LayerShellConfig
 from .utils import (
     cleanup_ssh_control_masters,
-    detach,
     expandvars,
     get_custom_window_icon,
     log_error,
@@ -514,7 +513,6 @@ def _main() -> None:
         if cli_opts.session == '-':
             from .session import PreReadSession
             cli_opts.session = PreReadSession(sys.stdin.read(), os.environ)
-        detach(talk_fd)
     if cli_opts.replay_commands:
         from kitty.client import main as client_main
         client_main(cli_opts.replay_commands)

kitty/utils.py

@@ -257,25 +257,6 @@ def open_url(url: str, program: str | list[str] = 'default', cwd: str | None = N
     return open_cmd(command_for_open(program), url, cwd=cwd, extra_env=extra_env)
 
 
-def detach(*preserve_fds: int, fork: bool = True, setsid: bool = True, redirect: bool = True, log_file: str = os.devnull) -> None:
-    reset = []
-    for fd in preserve_fds:
-        if fd > -1 and not os.get_inheritable(fd):
-            os.set_inheritable(fd, True)
-            reset.append(fd)
-    if fork:
-        # Detach from the controlling process.
-        if os.fork() != 0:
-            raise SystemExit(0)
-    for fd in reset:
-        os.set_inheritable(fd, False)
-    if setsid:
-        os.setsid()
-    if redirect:
-        from .fast_data_types import redirect_std_streams
-        redirect_std_streams(stdin=os.devnull, stdout=log_file, stderr=log_file)
-
-
 def init_startup_notification_x11(window_handle: int, startup_id: str | None = None) -> Optional['StartupCtx']:
     # https://specifications.freedesktop.org/startup-notification-spec/startup-notification-latest.txt
     from kitty.fast_data_types import init_x11_startup_notification