Add chkblayout(1).

doc/user-guide

@@ -22,10 +22,32 @@ to those of Unix systems and many common Unix commands are available.
 Keyboard Layout
 ---------------
 
-Only the US Keyboard layout is supported at this time. The whole system uses
-UTF-8 as the standard text encoding. However, the console has limited font data
-at this time and it is not possible to enter many characters. A full keyboard
-layout system has been implemented but was not merged in time for this release.
+The kernel translates the raw keyboard scancodes into unicode codepoints using
+the current keyboard layout table associated with the terminal. Such layout
+tables are compiled from a textual description into compressed binary tables
+using the `kblayout-compiler` program. The kernel has a default US keyboard
+layout integrated into it at compile time.
+
+You can change the current keyboard layout using the `chkblayout` program. It
+loads a keyboard layouts with the requested name from the `/share/kblayout`
+directory, or a user-supplied file if the path contains a slash. The system
+comes with a few existing keyboard layouts and more can be added if desired.
+
+* `dk'
+* `us'
+
+You can select a particular keyboard layout by typing something like:
+
+    chkblayout da_DK
+
+Mind that while the user-space programs and the kernel all handle text correctly
+as unicode, your console may not be able to render such code points. VGA text
+mode consoles, for instance, only has the VGA font available, which contains
+just codepage 437 characters. The console driver helpfully translates some
+unicode characters that look like codepage 437 characters into their lookalikes
+for rendering. The graphical kernel console reuses the VGA font internally, but
+has no hardware restrictions. In principle, support could be added such that
+user-space can upload font data to the kernel graphical console.
 
 Changing the Video Mode
 -----------------------
@@ -91,6 +113,7 @@ This as an incomplete list of the common top level directories in Sortix.
 * `/root` - Directory of the root user.
 * `/share` - Architecture independent files.
 * `/share/doc` - Documentation.
+* `/share/kblayout` - Keyboard layouts.
 * `/src` - System source code.
 * `/tmp` - Temporary files.
 
@@ -167,6 +190,7 @@ Sortix comes with a number of home-made programs. Here is an overview:
 * `benchsyscall` - slightly less useless benchmark
 * `carray` -  convert a binary file to a C array
 * `cat` - display file on terminal
+* `chkblayout` - change keyboard layout
 * `chmod` - change file mode bits
 * `chroot` - change the root directory
 * `chvideomode` - change display resolution

utils/.gitignore

@@ -1,6 +1,7 @@
 *.o
 basename
 cat
+chkblayout
 chmod
 chroot
 chvideomode

utils/Makefile

@@ -13,6 +13,7 @@ CXXFLAGS:=$(CXXFLAGS) -Wall -Wextra -fno-exceptions -fno-rtti
 BINARIES_EXCEPT_INSTALL:=\
 basename \
 cat \
+chkblayout \
 chmod \
 chroot \
 chvideomode \

utils/chkblayout.cpp

@@ -0,0 +1,149 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2014.
+
+    This program is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    This program is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+    more details.
+
+    You should have received a copy of the GNU General Public License along with
+    this program. If not, see <http://www.gnu.org/licenses/>.
+
+    chkblayout.cpp
+    Changes the current keyboard layout.
+
+*******************************************************************************/
+
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <error.h>
+#include <fcntl.h>
+#include <ioleast.h>
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <termios.h>
+
+static void compact_arguments(int* argc, char*** argv)
+{
+	for ( int i = 0; i < *argc; i++ )
+	{
+		while ( i < *argc && !(*argv)[i] )
+		{
+			for ( int n = i; n < *argc; n++ )
+				(*argv)[n] = (*argv)[n+1];
+			(*argc)--;
+		}
+	}
+}
+
+static void help(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "Usage: %s [OPTION...] [LAYOUT-NAME]\n", argv0);
+	fprintf(fp, "Changes the current keyboard layout.\n");
+	fprintf(fp, "\n");
+	fprintf(fp, "Options supported by %s:\n", argv0);
+	fprintf(fp, "  --help             Display this help and exit\n");
+	fprintf(fp, "  --version          Output version information and exit\n");
+}
+
+static void version(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
+	fprintf(fp, "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.\n");
+	fprintf(fp, "This is free software: you are free to change and redistribute it.\n");
+	fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n");
+}
+
+int main(int argc, char* argv[])
+{
+	setlocale(LC_ALL, "");
+
+	const char* argv0 = argv[0];
+	for ( int i = 1; i < argc; i++ )
+	{
+		const char* arg = argv[i];
+		if ( arg[0] != '-' || !arg[1] )
+			continue;
+		argv[i] = NULL;
+		if ( !strcmp(arg, "--") )
+			break;
+		if ( arg[1] != '-' )
+		{
+			while ( char c = *++arg ) switch ( c )
+			{
+			default:
+				fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
+				help(stderr, argv0);
+				exit(1);
+			}
+		}
+		else if ( !strcmp(arg, "--help") )
+			help(stdout, argv0), exit(0);
+		else if ( !strcmp(arg, "--version") )
+			version(stdout, argv0), exit(0);
+		else
+		{
+			fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
+			help(stderr, argv0);
+			exit(1);
+		}
+	}
+
+	compact_arguments(&argc, &argv);
+
+	const char* tty_path = "/dev/tty";
+	int tty_fd = open(tty_path, O_WRONLY);
+	if ( tty_fd < 0 )
+		error(1, errno, "`%s'", tty_path);
+	if ( !isatty(tty_fd) )
+		error(1, errno, "`%s'", tty_path);
+
+	if ( argc == 1 )
+		error(1, 0, "expected path to new keyboard layout");
+
+	const char* kblayout_path = argv[1];
+	if ( !strchr(kblayout_path, '/') )
+	{
+		char* new_kblayout_path;
+		if ( asprintf(&new_kblayout_path, "/share/kblayout/%s", kblayout_path) < 0 )
+			error(1, errno, "asprintf");
+		kblayout_path = new_kblayout_path;
+	}
+	int kblayout_fd = open(kblayout_path, O_RDONLY);
+	if ( kblayout_fd < 0 )
+		error(1, errno, "`%s'", kblayout_path);
+
+	struct stat kblayout_st;
+	if ( fstat(kblayout_fd, &kblayout_st) < 0 )
+		error(1, errno, "stat: `%s'", kblayout_path);
+
+	if ( SIZE_MAX < (size_t) kblayout_st.st_size )
+		error(1, EFBIG, "`%s'", kblayout_path);
+
+	size_t kblayout_size = (size_t) kblayout_st.st_size;
+	unsigned char* kblayout = (unsigned char*) malloc(kblayout_size);
+	if ( !kblayout )
+		error(1, errno, "malloc");
+	if ( readall(kblayout_fd, kblayout, kblayout_size) != kblayout_size )
+		error(1, errno, "read: `%s'", kblayout_path);
+	close(kblayout_fd);
+
+	if ( tcsetblob(tty_fd, "kblayout", kblayout, kblayout_size) < 0 )
+		error(1, errno, "tcsetblob(\"kblayout\", `%s')", kblayout_path);
+
+	free(kblayout);
+
+	close(tty_fd);
+
+	return 0;
+}