When Kakoune's terminal is shown on my laptop monitor and I plug
in my external monitor, the terminal's workspace will move to that
external monitor. When this happens, Kakoune may segfault.
There are multiple resize events (SIGWINCH) in quick succession;
it crashes because we handle SIGWINCH during rendering.
The problem happens during execution of "TerminalUI::Screen::output"
(frame #18). When we receive SIGWINCH while writing to stdout, write(2)
fails with EAGAIN, prompting us to handle pending events (See ae001a1f9
(Run EventManager whenever writing to a file descriptor would block,
2022-05-10)). We update the screen size in check_resize() here:
#4 Kakoune::TerminalUI::check_resize (force=<optimized out>) at terminal_ui.cc:683
#5 Kakoune::TerminalUI::get_next_key () at terminal_ui.cc:719
#6 operator() (__closure=0x555555984198) at terminal_ui.cc:484
#7 std::__invoke_impl<void, Kakoune::TerminalUI::TerminalUI()::<lambda(Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode)>&, Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode> (__f=...) at /usr/include/c++/12.2.1/bits/invoke.h:61
#8 std::__invoke_r<void, Kakoune::TerminalUI::TerminalUI()::<lambda(Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode)>&, Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode> (__fn=...) at /usr/include/c++/12.2.1/bits/invoke.h:111
#9 std::_Function_handler<void(Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode), Kakoune::TerminalUI::TerminalUI()::<lambda(Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode)> >::_M_invoke(const std::_Any_data &, Kakoune::FDWatcher &, Kakoune::FdEvents &&, Kakoune::EventMode &&) (__functor=..., __args#0=..., __args#1=<optimized out>, __args#2=<optimized out>) at /usr/include/c++/12.2.1/bits/std_function.h:290
#10 std::function<void (Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode)>::operator()(Kakoune::FDWatcher&, Kakoune::FdEvents, Kakoune::EventMode) const (__args#2=<optimized out>, __args#1=<optimized out>, __args#0=...) at /usr/include/c++/12.2.1/bits/std_function.h:591
#11 Kakoune::FDWatcher::run (mode=Kakoune::EventMode::Urgent, events=<optimized out>) at event_manager.cc:28
#12 Kakoune::EventManager::handle_next_events (mode=mode@entry=Kakoune::EventMode::Urgent, sigmask=sigmask@entry=0x0, block=<optimized out>, block@entry=false) at event_manager.cc:143
#13 Kakoune::write (fd=1, data=...) at file.cc:273
#14 Kakoune::BufferedWriter<4096>::flush () at string.hh:236
#15 Kakoune::BufferedWriter<4096>::write (data="t file.hh:145
#16 Kakoune::TerminalUI::Screen::set_face (face=..., writer=...) at terminal_ui.cc:255
#17 operator() (line=..., __closure=<synthetic pointer>) at terminal_ui.cc:326
#18 Kakoune::TerminalUI::Screen::output (force=force@entry=true, synchronized=<optimized out>, writer=...) at terminal_ui.cc:402
#19 Kakoune::TerminalUI::redraw (force=force@entry=true) at terminal_ui.cc:571
#20 Kakoune::TerminalUI::refresh (force=<optimized out>) at terminal_ui.cc:592
#21 Kakoune::Client::redraw_ifn () at client.cc:282
#22 Kakoune::ClientManager::redraw_clients () at client_manager.cc:232
#23 Kakoune::run_server (session=..., server_init=..., client_init=..., init_buffer="fish-rust/src/ast.rs", init_coord=..., flags=Kakoune::ServerFlags::None, ui_type=Kakoune::UIType::Terminal,
debug_flags=<optimized out>, files=ArrayView<Kakoune::StringView> = {...}) at main.cc:893
#24 main (argc=<optimized out>, argv=<optimized out>) at main.cc:1243
Thereafter, "TerminalUI::Screen::output" resumes and crashes due to
a buffer overflow in "lines" which has been resized.
This permit to choose if files should be written by overwriting their
content (the default), or by writing to a separate temporary file
and rename it to the current file.
As discussed in #2036
In the end, % is not that painful to work with as its only set seldomly,
and we usually dont need to use expansion at the same time. Moreover, it
just requires a single \ to be escaped.
Fixes#1562
This commit allows "forced" writes to a write-protected file, by
attempting to temporarily grant the current user write permissions on
it. After the buffer has been written, the previous permissions are
restored if the file existed, or set to 0644 otherwise.
Reloading used to be implicit in the buffer creation function,
which is not always nice, as code that explicitely wanted to
reload a buffer could not say so.
