Add /dev/null.

sortix/Makefile

@@ -93,6 +93,7 @@ elf.o \
 fcache.o \
 fsfunc.o \
 fs/kram.o \
+fs/null.o \
 fs/user.o \
 fs/util.o \
 identity.o \

sortix/fs/null.cpp

@@ -0,0 +1,90 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2013.
+
+    This file is part of Sortix.
+
+    Sortix 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.
+
+    Sortix 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
+    Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+    fs/null.cpp
+    Bit bucket special device.
+
+*******************************************************************************/
+
+#include <sys/types.h>
+
+#include <stdint.h>
+
+#include <sortix/stat.h>
+
+#include <sortix/kernel/inode.h>
+
+#include "null.h"
+
+namespace Sortix {
+
+Null::Null(dev_t dev, ino_t ino, uid_t owner, gid_t group, mode_t mode)
+{
+	inode_type = INODE_TYPE_STREAM;
+	if ( !dev )
+		dev = (dev_t) this;
+	if ( !ino )
+		ino = (ino_t) this;
+	this->type = S_IFCHR;
+	this->stat_uid = owner;
+	this->stat_gid = group;
+	this->stat_mode = (mode & S_SETABLE) | this->type;
+	this->stat_size = 0;
+	this->stat_blksize = 1;
+	this->dev = dev;
+	this->ino = ino;
+}
+
+Null::~Null()
+{
+}
+
+int Null::truncate(ioctx_t* /*ctx*/, off_t /*length*/)
+{
+	return 0;
+}
+
+off_t Null::lseek(ioctx_t* /*ctx*/, off_t offset, int /*whence*/)
+{
+	return offset;
+}
+
+ssize_t Null::read(ioctx_t* /*ctx*/, uint8_t* /*buf*/, size_t /*count*/)
+{
+	return 0;
+}
+
+ssize_t Null::pread(ioctx_t* /*ctx*/, uint8_t* /*buf*/, size_t /*count*/,
+                    off_t /*off*/)
+{
+	return 0;
+}
+
+ssize_t Null::write(ioctx_t* /*ctx*/, const uint8_t* /*buf*/, size_t count)
+{
+	return count;
+}
+
+ssize_t Null::pwrite(ioctx_t* /*ctx*/, const uint8_t* /*buf*/, size_t count,
+                    off_t /*off*/)
+{
+	return count;
+}
+
+} // namespace Sortix

sortix/fs/null.h

@@ -0,0 +1,48 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2013.
+
+    This file is part of Sortix.
+
+    Sortix 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.
+
+    Sortix 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
+    Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+    fs/null.h
+    Bit bucket special device.
+
+*******************************************************************************/
+
+#ifndef SORTIX_FS_NULL_H
+#define SORTIX_FS_NULL_H
+
+#include <sortix/kernel/inode.h>
+
+namespace Sortix {
+
+class Null : public AbstractInode
+{
+public:
+	Null(dev_t dev, ino_t ino, uid_t owner, gid_t group, mode_t mode);
+	virtual ~Null();
+	virtual int truncate(ioctx_t* ctx, off_t length);
+	virtual off_t lseek(ioctx_t* ctx, off_t offset, int whence);
+	virtual ssize_t read(ioctx_t* ctx, uint8_t* buf, size_t count);
+	virtual ssize_t pread(ioctx_t* ctx, uint8_t* buf, size_t count, off_t off);
+	virtual ssize_t write(ioctx_t* ctx, const uint8_t* buf, size_t count);
+	virtual ssize_t pwrite(ioctx_t* ctx, const uint8_t* buf, size_t count,
+	                       off_t off);
+};
+
+} // namespace Sortix
+
+#endif

sortix/kernel.cpp

@@ -73,6 +73,7 @@
 #include "dispmsg.h"
 #include "elf.h"
 #include "fs/kram.h"
+#include "fs/null.h"
 #include "fs/user.h"
 #include "identity.h"
 #include "initrd.h"
@@ -529,6 +530,14 @@ static void BootThread(void* /*user*/)
 	if ( LinkInodeInDir(&ctx, slashdev, "tty", tty) != 0 )
 		Panic("Unable to link /dev/tty to kernel terminal.");
 
+	// Register the null device as /dev/null.
+	Ref<Inode> null_device(new Null(slashdev->dev, (ino_t) 0, (uid_t) 0,
+	                                (gid_t) 0, (mode_t) 0666));
+	if ( !null_device )
+		Panic("Could not allocate a null device");
+	if ( LinkInodeInDir(&ctx, slashdev, "null", null_device) != 0 )
+		Panic("Unable to link /dev/null to the null device.");
+
 	// Initialize the COM ports.
 	COM::Init("/dev", slashdev);