Index: uspace/srv/bd/file_bd/Makefile
===================================================================
--- uspace/srv/bd/file_bd/Makefile	(revision 1cbed6b67e561945fc06922f3d178d328ae94041)
+++ uspace/srv/bd/file_bd/Makefile	(revision 1cbed6b67e561945fc06922f3d178d328ae94041)
@@ -0,0 +1,76 @@
+#
+# Copyright (c) 2006 Martin Decky
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# - Redistributions of source code must retain the above copyright
+#   notice, this list of conditions and the following disclaimer.
+# - Redistributions in binary form must reproduce the above copyright
+#   notice, this list of conditions and the following disclaimer in the
+#   documentation and/or other materials provided with the distribution.
+# - The name of the author may not be used to endorse or promote products
+#   derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+## Setup toolchain
+#
+
+
+LIBC_PREFIX = ../../../lib/libc
+SOFTINT_PREFIX = ../../../lib/softint
+
+include $(LIBC_PREFIX)/Makefile.toolchain
+
+LIBS = $(LIBC_PREFIX)/libc.a
+
+## Sources
+#
+
+OUTPUT = file_bd
+SOURCES = \
+	file_bd.c
+
+OBJECTS := $(addsuffix .o,$(basename $(SOURCES)))
+
+.PHONY: all clean depend disasm
+
+all: $(OUTPUT) $(OUTPUT).disasm
+
+-include Makefile.depend
+
+clean:
+	-rm -f $(OUTPUT) $(OUTPUT).map $(OUTPUT).disasm Makefile.depend $(OBJECTS)
+
+depend:
+	$(CC) $(DEFS) $(CFLAGS) -M $(SOURCES) > Makefile.depend
+
+$(OUTPUT): $(OBJECTS) $(LIBS)
+	$(LD) -T $(LIBC_PREFIX)/arch/$(UARCH)/_link.ld $(OBJECTS) $(LIBS) $(LFLAGS) -o $@ -Map $(OUTPUT).map
+
+disasm: $(OUTPUT).disasm
+
+$(OUTPUT).disasm: $(OUTPUT)
+	$(OBJDUMP) -d $< > $@
+
+%.o: %.S
+	$(CC) $(DEFS) $(AFLAGS) $(CFLAGS) -D__ASM__ -c $< -o $@
+
+%.o: %.s
+	$(AS) $(AFLAGS) $< -o $@
+
+%.o: %.c
+	$(CC) $(DEFS) $(CFLAGS) -c $< -o $@
Index: uspace/srv/bd/file_bd/file_bd.c
===================================================================
--- uspace/srv/bd/file_bd/file_bd.c	(revision 1cbed6b67e561945fc06922f3d178d328ae94041)
+++ uspace/srv/bd/file_bd/file_bd.c	(revision 1cbed6b67e561945fc06922f3d178d328ae94041)
@@ -0,0 +1,217 @@
+/*
+ * Copyright (c) 2009 Jiri Svoboda
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** @addtogroup bd
+ * @{
+ */
+
+/**
+ * @file
+ * @brief File-backed block device driver
+ *
+ * Allows accessing a file as a block device. Useful for, e.g., mounting
+ * a disk image.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <ipc/ipc.h>
+#include <ipc/bd.h>
+#include <async.h>
+#include <as.h>
+#include <futex.h>
+#include <devmap.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <bool.h>
+
+#define NAME "file_bd"
+
+static size_t comm_size;
+static FILE *img;
+
+static dev_handle_t dev_handle;
+static atomic_t dev_futex = FUTEX_INITIALIZER;
+
+static int file_bd_init(const char *fname);
+static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall);
+static int file_bd_read(off_t blk_idx, off_t size, void *buf);
+static int file_bd_write(off_t blk_idx, off_t size, void *buf);
+
+int main(int argc, char **argv)
+{
+	int rc;
+
+	printf(NAME ": File-backed block device driver\n");
+
+	if (argc != 3) {
+		printf("Expected two arguments (image name, device name).\n");
+		return -1;
+	}
+
+	if (file_bd_init(argv[1]) != EOK)
+		return -1;
+
+	rc = devmap_device_register(argv[2], &dev_handle);
+	if (rc != EOK) {
+		devmap_hangup_phone(DEVMAP_DRIVER);
+		printf(NAME ": Unable to register device %s.\n",
+			argv[2]);
+		return rc;
+	}
+
+	printf(NAME ": Accepting connections\n");
+	async_manager();
+
+	/* Not reached */
+	return 0;
+}
+
+static int file_bd_init(const char *fname)
+{
+	int rc;
+
+	rc = devmap_driver_register(NAME, file_bd_connection);
+	if (rc < 0) {
+		printf(NAME ": Unable to register driver.\n");
+		return rc;
+	}
+
+	img = fopen(fname, "rb+");
+	if (img == NULL)
+		return EINVAL;
+
+	return EOK;
+}
+
+static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall)
+{
+	void *fs_va = NULL;
+	ipc_callid_t callid;
+	ipc_call_t call;
+	ipcarg_t method;
+	int flags;
+	int retval;
+	off_t idx;
+	off_t size;
+
+	/* Answer the IPC_M_CONNECT_ME_TO call. */
+	ipc_answer_0(iid, EOK);
+
+	if (!ipc_share_out_receive(&callid, &comm_size, &flags)) {
+		ipc_answer_0(callid, EHANGUP);
+		return;
+	}
+
+	fs_va = as_get_mappable_page(comm_size);
+	if (fs_va == NULL) {
+		ipc_answer_0(callid, EHANGUP);
+		return;
+	}
+
+	(void) ipc_share_out_finalize(callid, fs_va);
+
+	while (1) {
+		callid = async_get_call(&call);
+		method = IPC_GET_METHOD(call);
+		switch (method) {
+		case IPC_M_PHONE_HUNGUP:
+			/* The other side has hung up. */
+			ipc_answer_0(callid, EOK);
+			return;
+		case BD_READ_BLOCK:
+		case BD_WRITE_BLOCK:
+			idx = IPC_GET_ARG1(call);
+			size = IPC_GET_ARG2(call);
+			if (size > comm_size) {
+				retval = EINVAL;
+				break;
+			}
+			if (method == BD_READ_BLOCK)
+				retval = file_bd_read(idx, size, fs_va);
+			else
+				retval = file_bd_write(idx, size, fs_va);
+			break;
+		default:
+			retval = EINVAL;
+			break;
+		}
+		ipc_answer_0(callid, retval);
+	}
+}
+
+static int file_bd_read(off_t blk_idx, off_t size, void *buf)
+{
+	size_t n_rd;
+
+	printf("file_bd_read\n");
+	futex_down(&dev_futex);
+
+	printf("seek\n");
+	fseek(img, blk_idx * size, SEEK_SET);
+	printf("read\n");
+	n_rd = fread(buf, 1, size, img);
+	printf("done\n");
+
+	printf("done\n");
+
+	if (ferror(img)) {
+		futex_up(&dev_futex);
+		return EIO;	/* Read error */
+	}
+
+	futex_up(&dev_futex);
+
+	if (n_rd < size) 
+		return EINVAL;	/* Read beyond end of disk */
+
+	return EOK;
+}
+
+static int file_bd_write(off_t blk_idx, off_t size, void *buf)
+{
+	size_t n_wr;
+
+	futex_down(&dev_futex);
+
+	fseek(img, blk_idx * size, SEEK_SET);
+	n_wr = fread(buf, 1, size, img);
+
+	if (ferror(img) || n_wr < size) {
+		futex_up(&dev_futex);
+		return EIO;	/* Write error */
+	}
+
+	futex_up(&dev_futex);
+
+	return EOK;
+}
+
+/**
+ * @}
+ */