kakoune/src/client.cc
Johannes Altmanninger ec44d98347 Send SIGTERM on <c-c>, to more reliably kill background jobs
Consider

    sh -c 'sleep 5 & sleep inf'

Since the shell is non-interactive, there is no job control.
This makes the shell spawn the "sleep 5" process in the shell's own
process group[1] - presumably, because only interactive shells have
a need to forward signals to all processes in its foreground job.

When this non-interactive shell process is cancelled with SIGINT,
"sleep 5" keeps running [2]. At least the dash shell implements this
by running "signal(SIGINT, SIG_IGN)" in the forked child.  Unless the
child process explicitly overrides that (to SIG_DFL for example), it
will ignore SIGINT. Probably the reason for this behavior is to feign
consistency with interactive shells, without needing to actually run
background jobs in a dedicated process group like interactive shells
do. Bash documents this behavior[3]:

> When job control is not in effect, asynchronous commands ignore
> SIGINT and SIGQUIT in addition to these inherited handlers.

Several of our scripts[4] - most prominently ":make" - use the
"</dev/null >/dev/null 2>&1 &" pattern to run potentially long-running
processes in the background, without blocking the editor.

On <c-c>, we send SIGINT to our process group.
As explained above, this will generally not terminate any background processes.

This problem has been masked by a behavior that is unique to using
both Bash and its "eval" builtin. Given

    nop %sh{
        rm -f /tmp/fifo
        mkfifo /tmp/fifo
        (
            eval make >/tmp/fifo 2>&1 &
        ) >/dev/null 2>&1 </dev/null
    }
    edit -fifo /tmp/fifo *my-fifo*

When running this and pressing Control+C, Bash actually terminates
the Make processes. However if I remove the "eval", it no longer does.
This doesn't seems like something we should rely on.
Other commands like ":git blame" don't use "eval" so they cannot be
cancelled today.

Fix these issues by sending SIGTERM instead of SIGINT, which should
apply to the whole process group with pretty much the same effect.
Barely tested, let's see if this breaks some weird build system.

In future we might allow more fine-grained control over which processes
are cancelled by <c-c>.

{{{

Alternative solution:

With the above fix, scripts can opt-out of being terminated by <c-c>
by using setsid (though that's not POSIX unfortunately, and may
require nesting quotes) or the classic Unix double-forking trick to
create a daemon process.

Though it is certainly possible that someone expects commands like
this to survive <c-c>:

    nop %sh{ tail -f my-log </dev/null 2>&1 | grep some-error > some-file 2>&1 & }

I think it would be ideal to stick to SIGINT and match semantics of
a noninteractive shell, to avoid muddying the waters.

Background processes could still **opt into** being terminated by
<c-c>. For example by providing a simple program in libexec/ that does

    // interruptible.c
    int main(int argc, char** argv) {
        signal(SIGINT, SIG_DFL);
        execv(argv[1], &argv[1]);
    }

used as

    diff --git a/rc/tools/make.kak b/rc/tools/make.kak
    index b88f7e538..f6e041908 100644
    --- a/rc/tools/make.kak
    +++ b/rc/tools/make.kak
    @@ -16,3 +16,3 @@ define-command -params .. \
          mkfifo ${output}
    -     ( eval "${kak_opt_makecmd}" "$@" > ${output} 2>&1 & ) > /dev/null 2>&1 < /dev/null
    +     ( eval "interruptible ${kak_opt_makecmd}" "$@" > ${output} 2>&1 & ) > /dev/null 2>&1 < /dev/null

Unfortunately, it's inconvenient to add "interruptible" to commands
like clang-parse and git-blame because they background a whole subshell
with many commands, so we'd need to nest quotes.  Also I'm not sure
if this brings any benefit.

So I didn't explore this further yet although we can definitely do that.

}}}

Fixes #3751

[1]: https://stackoverflow.com/questions/45106725/why-do-shells-ignore-sigint-and-sigquit-in-backgrounded-processes/45106961#45106961
[2]: https://unix.stackexchange.com/questions/372541/why-doesnt-sigint-work-on-a-background-process-in-a-script/677742#677742
[3]: https://www.gnu.org/software/bash/manual/html_node/Signals.html
[4]: clang-parse, ctags-*, git blame, git log, gopls references,
     grep, jedi-complete, lint-*, make; I don't think any of these
     should be uninterruptible.
2024-03-08 20:10:15 +11:00

489 lines
16 KiB
C++

#include "client.hh"
#include "face_registry.hh"
#include "context.hh"
#include "buffer_manager.hh"
#include "buffer_utils.hh"
#include "file.hh"
#include "remote.hh"
#include "option.hh"
#include "option_types.hh"
#include "client_manager.hh"
#include "command_manager.hh"
#include "event_manager.hh"
#include "user_interface.hh"
#include "window.hh"
#include "hash_map.hh"
#include <csignal>
#include <unistd.h>
#include <utility>
namespace Kakoune
{
Client::Client(std::unique_ptr<UserInterface>&& ui,
std::unique_ptr<Window>&& window,
SelectionList selections, int pid,
EnvVarMap env_vars,
String name,
OnExitCallback on_exit)
: m_ui{std::move(ui)}, m_window{std::move(window)},
m_pid{pid},
m_on_exit{std::move(on_exit)},
m_env_vars(std::move(env_vars)),
m_input_handler{std::move(selections), Context::Flags::None,
std::move(name)}
{
m_window->set_client(this);
context().set_client(*this);
context().set_window(*m_window);
m_window->set_dimensions(m_ui->dimensions());
m_window->options().register_watcher(*this);
m_ui->set_ui_options(m_window->options()["ui_options"].get<UserInterface::Options>());
m_ui->set_on_key([this](Key key) {
kak_assert(key != Key::Invalid);
if (key == ctrl('c'))
{
auto prev_handler = set_signal_handler(SIGTERM, SIG_IGN);
killpg(getpgrp(), SIGTERM);
set_signal_handler(SIGTERM, prev_handler);
}
else if (key == ctrl('g'))
{
m_pending_keys.clear();
print_status({"operation cancelled", context().faces()["Error"]});
throw cancel{};
}
else if (key.modifiers & Key::Modifiers::Resize)
{
m_window->set_dimensions(key.coord());
force_redraw(true);
}
else
m_pending_keys.push_back(key);
});
m_ui->set_on_paste([this](StringView content) {
context().input_handler().paste(content);
});
m_window->hooks().run_hook(Hook::WinDisplay, m_window->buffer().name(), context());
force_redraw();
}
Client::~Client()
{
m_window->options().unregister_watcher(*this);
m_window->set_client(nullptr);
// Do not move the selections here, as we need them to be valid
// in order to correctly destroy the input handler
ClientManager::instance().add_free_window(std::move(m_window),
context().selections());
}
bool Client::is_ui_ok() const
{
return m_ui->is_ok();
}
bool Client::process_pending_inputs()
{
const bool debug_keys = (bool)(context().options()["debug"].get<DebugFlags>() & DebugFlags::Keys);
m_window->run_resize_hook_ifn();
// steal keys as we might receive new keys while handling them.
Vector<Key, MemoryDomain::Client> keys = std::move(m_pending_keys);
for (auto& key : keys)
{
try
{
if (debug_keys)
write_to_debug_buffer(format("Client '{}' got key '{}'", context().name(), key));
if (key == Key::FocusIn)
context().hooks().run_hook(Hook::FocusIn, context().name(), context());
else if (key == Key::FocusOut)
context().hooks().run_hook(Hook::FocusOut, context().name(), context());
else
{
context().ensure_cursor_visible = true;
m_input_handler.handle_key(key);
}
context().hooks().run_hook(Hook::RawKey, to_string(key), context());
}
catch (Kakoune::runtime_error& error)
{
write_to_debug_buffer(format("Error: {}", error.what()));
context().print_status({error.what().str(), context().faces()["Error"]});
context().hooks().run_hook(Hook::RuntimeError, error.what(), context());
}
}
return not keys.empty();
}
void Client::print_status(DisplayLine status_line)
{
m_status_line = std::move(status_line);
m_ui_pending |= StatusLine;
}
DisplayCoord Client::dimensions() const
{
return m_ui->dimensions();
}
String generate_context_info(const Context& context)
{
String s = "";
if (context.buffer().is_modified())
s += "[+]";
if (context.client().input_handler().is_recording())
s += format("[recording ({})]", context.client().input_handler().recording_reg());
if (context.hooks_disabled())
s += "[no-hooks]";
if (not(context.buffer().flags() & (Buffer::Flags::File | Buffer::Flags::Debug)))
s += "[scratch]";
if (context.buffer().flags() & Buffer::Flags::New)
s += "[new file]";
if (context.buffer().flags() & Buffer::Flags::Fifo)
s += "[fifo]";
if (context.buffer().flags() & Buffer::Flags::Debug)
s += "[debug]";
if (context.buffer().flags() & Buffer::Flags::ReadOnly)
s += "[readonly]";
return s;
}
DisplayLine Client::generate_mode_line() const
{
DisplayLine modeline;
try
{
const String& modelinefmt = context().options()["modelinefmt"].get<String>();
HashMap<String, DisplayLine> atoms{{ "mode_info", context().client().input_handler().mode_line() },
{ "context_info", {generate_context_info(context()),
context().faces()["Information"]}}};
auto expanded = expand(modelinefmt, context(), ShellContext{},
[](String s) { return escape(s, '{', '\\'); });
modeline = parse_display_line(expanded, context().faces(), atoms);
}
catch (runtime_error& err)
{
write_to_debug_buffer(format("Error while parsing modelinefmt: {}", err.what()));
modeline.push_back({ "modelinefmt error, see *debug* buffer", context().faces()["Error"] });
}
return modeline;
}
void Client::change_buffer(Buffer& buffer, Optional<FunctionRef<void()>> set_selections)
{
if (m_buffer_reload_dialog_opened)
close_buffer_reload_dialog();
auto& client_manager = ClientManager::instance();
WindowAndSelections ws = client_manager.get_free_window(buffer);
m_window->options().unregister_watcher(*this);
m_window->set_client(nullptr);
client_manager.add_free_window(std::move(m_window),
context().selections());
m_window = std::move(ws.window);
m_window->set_client(this);
m_window->options().register_watcher(*this);
if (set_selections)
(*set_selections)();
else
{
ScopedSelectionEdition selection_edition{context()};
context().selections_write_only() = std::move(ws.selections);
}
context().set_window(*m_window);
m_window->set_dimensions(m_ui->dimensions());
m_ui->set_ui_options(m_window->options()["ui_options"].get<UserInterface::Options>());
m_window->hooks().run_hook(Hook::WinDisplay, buffer.name(), context());
force_redraw(true);
}
static bool is_inline(InfoStyle style)
{
return style == InfoStyle::Inline or
style == InfoStyle::InlineAbove or
style == InfoStyle::InlineBelow;
}
void Client::redraw_ifn()
{
Window& window = context().window();
if (window.needs_redraw(context()))
m_ui_pending |= Draw;
DisplayLine mode_line = generate_mode_line();
if (mode_line.atoms() != m_mode_line.atoms())
{
m_ui_pending |= StatusLine;
m_mode_line = std::move(mode_line);
}
if (m_ui_pending == 0)
return;
const auto& faces = context().faces();
if (m_ui_pending & Draw)
m_ui->draw(window.update_display_buffer(context()),
faces["Default"], faces["BufferPadding"]);
const bool update_menu_anchor = (m_ui_pending & Draw) and not (m_ui_pending & MenuHide) and
not m_menu.items.empty() and m_menu.style == MenuStyle::Inline;
if ((m_ui_pending & MenuShow) or update_menu_anchor)
{
auto anchor = m_menu.style == MenuStyle::Inline ?
window.display_position(m_menu.anchor) : DisplayCoord{};
if (not (m_ui_pending & MenuShow) and m_menu.ui_anchor != anchor)
m_ui_pending |= anchor ? (MenuShow | MenuSelect) : MenuHide;
m_menu.ui_anchor = anchor;
}
if (m_ui_pending & MenuShow and m_menu.ui_anchor)
m_ui->menu_show(m_menu.items, *m_menu.ui_anchor,
faces["MenuForeground"], faces["MenuBackground"],
m_menu.style);
if (m_ui_pending & MenuSelect and m_menu.ui_anchor)
m_ui->menu_select(m_menu.selected);
if (m_ui_pending & MenuHide)
m_ui->menu_hide();
const bool update_info_anchor = (m_ui_pending & Draw) and not (m_ui_pending & InfoHide) and
not m_info.content.empty() and is_inline(m_info.style);
if ((m_ui_pending & InfoShow) or update_info_anchor)
{
auto anchor = is_inline(m_info.style) ?
window.display_position(m_info.anchor) : DisplayCoord{};
if (not (m_ui_pending & MenuShow) and m_info.ui_anchor != anchor)
m_ui_pending |= anchor ? InfoShow : InfoHide;
m_info.ui_anchor = anchor;
}
if (m_ui_pending & InfoShow and m_info.ui_anchor)
m_ui->info_show(m_info.title, m_info.content, *m_info.ui_anchor,
faces[(is_inline(m_info.style) || m_info.style == InfoStyle::MenuDoc)
? "InlineInformation" : "Information"], m_info.style);
if (m_ui_pending & InfoHide)
m_ui->info_hide();
if (m_ui_pending & StatusLine)
m_ui->draw_status(m_status_line, m_mode_line, faces["StatusLine"]);
auto cursor = m_input_handler.get_cursor_info();
m_ui->set_cursor(cursor.first, cursor.second);
m_ui->refresh(m_ui_pending & Refresh);
m_ui_pending = 0;
}
void Client::force_redraw(bool full)
{
if (full)
m_ui_pending |= Refresh | Draw | StatusLine |
(m_menu.items.empty() ? MenuHide : MenuShow | MenuSelect) |
(m_info.content.empty() ? InfoHide : InfoShow);
else
m_ui_pending |= Draw;
}
void Client::reload_buffer()
{
Buffer& buffer = context().buffer();
try
{
reload_file_buffer(buffer);
context().print_status({ format("'{}' reloaded", buffer.display_name()),
context().faces()["Information"] });
m_window->hooks().run_hook(Hook::BufReload, buffer.name(), context());
}
catch (runtime_error& error)
{
context().print_status({ format("error while reloading buffer: '{}'", error.what()),
context().faces()["Error"] });
buffer.set_fs_status(get_fs_status(buffer.name()));
}
}
void Client::on_buffer_reload_key(Key key)
{
auto& buffer = context().buffer();
auto set_autoreload = [this](Autoreload autoreload) {
auto* option = &context().options()["autoreload"];
// Do not touch global autoreload, set it at least at buffer level
if (&option->manager() == &GlobalScope::instance().options())
option = &context().buffer().options().get_local_option("autoreload");
option->set(autoreload);
};
if (key == 'y' or key == 'Y' or key == Key::Return)
{
reload_buffer();
if (key == 'Y')
set_autoreload(Autoreload::Yes);
}
else if (key == 'n' or key == 'N' or key == Key::Escape)
{
// reread timestamp in case the file was modified again
buffer.set_fs_status(get_fs_status(buffer.name()));
print_status({ format("'{}' kept", buffer.display_name()),
context().faces()["Information"] });
if (key == 'N')
set_autoreload(Autoreload::No);
}
else
{
print_status({ format("'{}' is not a valid choice", key),
context().faces()["Error"] });
m_input_handler.on_next_key("buffer-reload", KeymapMode::None, [this](Key key, Context&){ on_buffer_reload_key(key); });
return;
}
for (auto& client : ClientManager::instance())
{
if (&client->context().buffer() == &buffer and
client->m_buffer_reload_dialog_opened)
client->close_buffer_reload_dialog();
}
}
void Client::close_buffer_reload_dialog()
{
kak_assert(m_buffer_reload_dialog_opened);
// Reset first as this might check for reloading.
m_input_handler.reset_normal_mode();
m_buffer_reload_dialog_opened = false;
info_hide(true);
}
void Client::check_if_buffer_needs_reloading()
{
if (m_buffer_reload_dialog_opened)
return;
Buffer& buffer = context().buffer();
auto reload = context().options()["autoreload"].get<Autoreload>();
if (not (buffer.flags() & Buffer::Flags::File) or reload == Autoreload::No)
return;
try
{
const String& filename = buffer.name();
const timespec ts = get_fs_timestamp(filename);
const auto status = buffer.fs_status();
if (ts == InvalidTime or ts == status.timestamp)
return;
if (MappedFile fd{filename};
fd.st.st_size == status.file_size and murmur3(fd.data, fd.st.st_size) == status.hash)
return;
if (reload == Autoreload::Ask)
{
StringView bufname = buffer.display_name();
info_show(format("reload '{}' ?", bufname),
format("'{}' was modified externally\n"
" y, <ret>: reload | n, <esc>: keep\n"
" Y: always reload | N: always keep\n",
bufname), {}, InfoStyle::Modal);
m_buffer_reload_dialog_opened = true;
m_input_handler.on_next_key("buffer-reload", KeymapMode::None, [this](Key key, Context&){ on_buffer_reload_key(key); });
}
else
reload_buffer();
}
catch (Kakoune::runtime_error& error)
{
write_to_debug_buffer(format("Error while checking if buffer {} changed: {}", buffer.name(), error.what()));
}
}
StringView Client::get_env_var(StringView name) const
{
auto it = m_env_vars.find(name);
if (it == m_env_vars.end())
return {};
return it->value;
}
void Client::on_option_changed(const Option& option)
{
if (option.name() == "ui_options")
m_ui->set_ui_options(option.get<UserInterface::Options>());
m_ui_pending |= Draw; // a highlighter might depend on the option, so we need to redraw
}
void Client::menu_show(Vector<DisplayLine> choices, BufferCoord anchor, MenuStyle style)
{
m_menu = Menu{ std::move(choices), anchor, {}, style, -1 };
m_ui_pending |= MenuShow;
m_ui_pending &= ~MenuHide;
}
void Client::menu_select(int selected)
{
m_menu.selected = selected;
m_ui_pending |= MenuSelect;
m_ui_pending &= ~MenuHide;
}
void Client::menu_hide()
{
m_menu = Menu{};
m_ui_pending |= MenuHide;
m_ui_pending &= ~(MenuShow | MenuSelect);
}
void Client::info_show(DisplayLine title, DisplayLineList content, BufferCoord anchor, InfoStyle style)
{
if (m_info.style == InfoStyle::Modal) // We already have a modal info opened, do not touch it.
return;
m_info = Info{ std::move(title), std::move(content), anchor, {}, style };
m_ui_pending |= InfoShow;
m_ui_pending &= ~InfoHide;
}
void Client::info_show(StringView title, StringView content, BufferCoord anchor, InfoStyle style)
{
if (not content.empty() and content.back() == '\n')
content = content.substr(0, content.length() - 1);
info_show(title.empty() ? DisplayLine{} : DisplayLine{title.str(), Face{}},
content | split<StringView>('\n')
| transform([](StringView s) { return DisplayLine{replace(s, '\t', ' '), Face{}}; })
| gather<DisplayLineList>(),
anchor, style);
}
void Client::info_hide(bool even_modal)
{
if (not even_modal and m_info.style == InfoStyle::Modal)
return;
m_info = Info{};
m_ui_pending |= InfoHide;
m_ui_pending &= ~InfoShow;
}
}