godot-xterm/addons/godot_xterm/nodes/pty/unix/pty_unix.gd

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# Derived from https://github.com/microsoft/node-pty/blob/main/src/unixTerminal.ts
# Copyright (c) 2012-2015, Christopher Jeffrey (MIT License).
# Copyright (c) 2016, Daniel Imms (MIT License).
# Copyright (c) 2018, Microsoft Corporation (MIT License).
# Copyright (c) 2021-2022, Leroy Hopson (MIT License).
tool
extends "../pty_native.gd"
const LibuvUtils := preload("../libuv_utils.gd")
const Pipe := preload("../pipe.gdns")
const PTYUnix = preload("./pty_unix.gdns")
const DEFAULT_NAME := "xterm-256color"
const DEFAULT_COLS := 80
const DEFAULT_ROWS := 24
const DEFAULT_ENV := {TERM = DEFAULT_NAME, COLORTERM = "truecolor"}
const FALLBACK_FILE = "sh"
## Default messages to indicate PAUSE/RESUME for automatic flow control.
## To avoid conflicts with rebound XON/XOFF control codes (such as on-my-zsh),
## the sequences can be customized in IPtyForkOptions.
#const FLOW_CONTROL_PAUSE = char(0x13) # defaults to XOFF
#const FLOW_CONTROL_RESUME = char(0x11) # defaults to XON
# Any signal_number can be sent to the pty's process using the kill() function,
# these are just the signals with numbers specified in the POSIX standard.
enum Signal {
SIGHUP = 1, # Hangup
SIGINT = 2, # Terminal interrupt signal
SIGQUIT = 3, # Terminal quit signal
SIGILL = 4, # Illegal instruction
SIGTRAP = 5, # Trace/breakpoint trap
SIGABRT = 6, # Process abort signal
SIGFPE = 8, # Erroneous arithmetic operation
SIGKILL = 9, # Kill (cannot be caught or ignored)
SIGSEGV = 11, # Invalid memory reference
SIGPIPE = 13, # Write on a pipe with no one to read it
SIGALRM = 14, # Alarm clock
SIGTERM = 15, # Termination signal
}
# The name of the process.
#var process: String
# The process ID.
var _pid: int
# Environment to be set for the child program.
var env := DEFAULT_ENV
# If true the environment variables in the env Dictionary will be merged with
# the environment variables of the operating system (e.g. printenv), with the
# former taking precedence in the case of conflicts.
var use_os_env := true
var _pipe: Pipe
# Security warning: use this option with great caution, as opened file descriptors
# with higher privileges might leak to the child program.
var uid: int
var gid: int
var _fd: int = -1
var _exit_cb: FuncRef
# Writes data to the socket.
# data: The data to write.
func write(data) -> void:
Fix unicode errors Changes `write()` method of native pipe and terminal to accept a PoolByteArray rather than String. This means that `get_string_from_utf8()` is no longer called on data coming from PTY and being sent to Terminal. The terminal state machine already has a UTF8 parser which maintains its state across calls to `write()`. This means that we can write half the bytes of a single unicode character in one call and the remaining half in the next call and the state machine will parse it correctly. On the other hand, the `get_string_from_utf8()` method of Godot's PoolByteArray requires that the array contains completely valid UTF8, otherwise we get errors such as "Unicode error: invalid skip". The data coming from PTY can be arbitrarily split in the middle of a unicode character meaning that we will sometimes get errors when calling `get_string_from_utf8()` on it. This is more likely to occur when there is a large amount of output (i.e. it's more likely to be split). In other cases, the data might intentionally contain invalid unicode such as when printing binary files or random data (e.g. `cat /bin/sh`, `cat /dev/random`). We avoid these errors by passing the PoolByteArray data directly to the terminal state machine. In addition to fixing unicode errors, this commit: - Prevents repeated calls to pipes `_read_cb()` method that would block Godot and result in a crash with the message "ERROR: All memory pool allocations are in use" that resulted from writing data to an ever-increasing number of PoolByteArrays before any of them could be freed. This could be triggered by running the `cat /dev/urandom` command after making the change to `write()` mentioned above. - Prevents memory leaks by freeing libuv buffers after they have been copied to PoolByteArrays. Fixes #55.
2022-08-14 09:45:17 +02:00
assert(
data is PoolByteArray or data is String,
"Invalid type for argument 'data'. Should be of type PoolByteArray or String"
)
if _pipe:
Fix unicode errors Changes `write()` method of native pipe and terminal to accept a PoolByteArray rather than String. This means that `get_string_from_utf8()` is no longer called on data coming from PTY and being sent to Terminal. The terminal state machine already has a UTF8 parser which maintains its state across calls to `write()`. This means that we can write half the bytes of a single unicode character in one call and the remaining half in the next call and the state machine will parse it correctly. On the other hand, the `get_string_from_utf8()` method of Godot's PoolByteArray requires that the array contains completely valid UTF8, otherwise we get errors such as "Unicode error: invalid skip". The data coming from PTY can be arbitrarily split in the middle of a unicode character meaning that we will sometimes get errors when calling `get_string_from_utf8()` on it. This is more likely to occur when there is a large amount of output (i.e. it's more likely to be split). In other cases, the data might intentionally contain invalid unicode such as when printing binary files or random data (e.g. `cat /bin/sh`, `cat /dev/random`). We avoid these errors by passing the PoolByteArray data directly to the terminal state machine. In addition to fixing unicode errors, this commit: - Prevents repeated calls to pipes `_read_cb()` method that would block Godot and result in a crash with the message "ERROR: All memory pool allocations are in use" that resulted from writing data to an ever-increasing number of PoolByteArrays before any of them could be freed. This could be triggered by running the `cat /dev/urandom` command after making the change to `write()` mentioned above. - Prevents memory leaks by freeing libuv buffers after they have been copied to PoolByteArrays. Fixes #55.
2022-08-14 09:45:17 +02:00
_pipe.write(data if data is PoolByteArray else data.to_utf8())
func resize(cols: int, rows: int) -> void:
if _fd >= 0:
PTYUnix.new().resize(_fd, cols, rows)
func kill(signum: int = Signal.SIGHUP) -> void:
if _pipe:
_pipe.close()
if _pid > 0:
LibuvUtils.kill(_pid, signum)
func _parse_env(env: Dictionary = {}) -> PoolStringArray:
var keys := env.keys()
var pairs := PoolStringArray()
for key in keys:
var value = env[key]
var valid = key is String and value is String
assert(valid, "Env key/value pairs must be of type String/String.")
if not valid:
push_warning("Skipping invalid env key/value pair.")
continue
pairs.append("%s=%s" % [key, value])
return pairs
func _process(_delta):
if _pipe:
_pipe.poll()
func fork(
file: String = OS.get_environment("SHELL"),
args: PoolStringArray = PoolStringArray(),
cwd = LibuvUtils.get_cwd(),
cols: int = DEFAULT_COLS,
rows: int = DEFAULT_ROWS,
uid: int = -1,
gid: int = -1,
utf8 = true
) -> int:
# File.
if file.empty():
file = FALLBACK_FILE
# Environment variables.
# If we are using OS env vars, sanitize them to remove variables that might confuse our terminal.
var final_env := _sanitize_env(LibuvUtils.get_os_environ()) if use_os_env else {}
for key in env.keys():
final_env[key] = env[key]
var parsed_env: PoolStringArray = _parse_env(final_env)
# Exit callback.
_exit_cb = FuncRef.new()
_exit_cb.set_instance(self)
_exit_cb.set_function("_on_exit")
# Actual fork.
var result = PTYUnix.new().fork( # VERY IMPORTANT: The must be set null or 0, otherwise will get an ENOTSOCK error after connecting our pipe to the fd.
file, null, args, parsed_env, cwd, cols, rows, uid, gid, utf8, _exit_cb
)
if result[0] != OK:
push_error("Fork failed.")
return FAILED
_fd = result[1].fd
if _fd < 0:
push_error("File descriptor must be a non-negative integer value.")
return FAILED
_pid = result[1].pid
_pipe = Pipe.new()
_pipe.open(_fd)
# Must connect to signal AFTER opening, otherwise we will get error ENOTSOCK.
_pipe.connect("data_received", self, "_on_pipe_data_received")
return OK
func open(cols: int = DEFAULT_COLS, rows: int = DEFAULT_ROWS) -> Array:
return PTYUnix.new().open(cols, rows)
func _exit_tree():
_exit_cb = null
if _pid > 1:
LibuvUtils.kill(_pid, Signal.SIGHUP)
if _pipe:
while _pipe.get_status() != 0:
continue
func _on_pipe_data_received(data):
emit_signal("data_received", data)
func _on_exit(exit_code: int, signum: int) -> void:
if is_instance_valid(self):
_pid = -1
emit_signal("exited", exit_code, signum)
func _sanitize_env(env: Dictionary) -> Dictionary:
# Make sure we didn't start our server from inside tmux.
env.erase("TMUX")
env.erase("TMUX_PANE")
# Make sure we didn't start our server from inside screen.
# http://web.mit.edu/gnu/doc/html/screen_20.html
env.erase("STY")
env.erase("WINDOW")
# Delete some variables that might confuse our terminal.
env.erase("WINDOWID")
env.erase("TERMCAP")
env.erase("COLUMNS")
env.erase("LINES")
return env