From c1012e6a45115c3422c71c6b109400fd7dc89c19 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Wed, 30 Oct 2019 21:19:11 +0100
Subject: [PATCH] libc: translate terminal user interrupts to SIGINT

Issue #3546
---
 repos/libports/src/lib/libc/internal/kernel.h |  5 ++
 repos/libports/src/lib/libc/kernel.cc         | 49 +++++++++++++++----
 2 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/repos/libports/src/lib/libc/internal/kernel.h b/repos/libports/src/lib/libc/internal/kernel.h
index 107bc09f3..06cbeb6dc 100644
--- a/repos/libports/src/lib/libc/internal/kernel.h
+++ b/repos/libports/src/lib/libc/internal/kernel.h
@@ -123,6 +123,11 @@ struct Libc::Kernel final : Vfs::Io_response_handler,
 
 		void _handle_terminal_resize();
 
+		/* handler for watching user interrupts (control-c) */
+		Constructible<Watch_handler<Kernel>> _user_interrupt_handler { };
+
+		void _handle_user_interrupt();
+
 		Signal _signal;
 
 		Reconstructible<Io_signal_handler<Kernel>> _resume_main_handler {
diff --git a/repos/libports/src/lib/libc/kernel.cc b/repos/libports/src/lib/libc/kernel.cc
index 2f30c33c6..fc4d36849 100644
--- a/repos/libports/src/lib/libc/kernel.cc
+++ b/repos/libports/src/lib/libc/kernel.cc
@@ -169,22 +169,44 @@ void Libc::Kernel::_init_file_descriptors()
 			file_descriptor_allocator()->preserve(fd);
 	}
 
+	/**
+	 * Call 'fn' with root directory and path to ioctl pseudo file as arguments
+	 *
+	 * If no matching ioctl pseudo file exists, 'fn' is not called.
+	 */
+	auto with_ioctl_path = [&] (File_descriptor const *fd, char const *file, auto fn)
+	{
+		if (!fd || !fd->fd_path)
+			return;
+
+		Absolute_path const ioctl_dir = Vfs_plugin::ioctl_dir(*fd);
+		Absolute_path path = ioctl_dir;
+		path.append_element(file);
+
+		_vfs.with_root_dir([&] (Directory &root_dir) {
+			if (root_dir.file_exists(path.string()))
+				fn(root_dir, path.string()); });
+	};
+
 	/*
-	 * Watch stdout's 'info' pseudo file to detect terminal resize events
+	 * Watch stdout's 'info' pseudo file to detect terminal-resize events
 	 */
 	File_descriptor const * const stdout_fd =
 		file_descriptor_allocator()->find_by_libc_fd(STDOUT_FILENO);
 
-	if (stdout_fd && stdout_fd->fd_path) {
-		Absolute_path dir = Vfs_plugin::ioctl_dir(*stdout_fd);
-		dir.append_element("info");
+	with_ioctl_path(stdout_fd, "info", [&] (Directory &root_dir, char const *path) {
+		_terminal_resize_handler.construct(root_dir, path, *this,
+		                                   &Kernel::_handle_terminal_resize); });
 
-		_vfs.with_root_dir([&] (Directory &root_dir) {
-			if (root_dir.file_exists(dir.string()))
-				_terminal_resize_handler.construct(root_dir, dir.string(),
-				                                   *this, &Kernel::_handle_terminal_resize);
-		});
-	}
+	/*
+	 * Watch stdin's 'interrupts' pseudo file to detect control-c events
+	 */
+	File_descriptor const * const stdin_fd =
+		file_descriptor_allocator()->find_by_libc_fd(STDIN_FILENO);
+
+	with_ioctl_path(stdin_fd, "interrupts", [&] (Directory &root_dir, char const *path) {
+		_user_interrupt_handler.construct(root_dir, path,
+		                                  *this, &Kernel::_handle_user_interrupt); });
 }
 
 
@@ -195,6 +217,13 @@ void Libc::Kernel::_handle_terminal_resize()
 }
 
 
+void Libc::Kernel::_handle_user_interrupt()
+{
+	_signal.charge(SIGINT);
+	_resume_main();
+}
+
+
 void Libc::Kernel::_clone_state_from_parent()
 {
 	struct Range { void *at; size_t size; };