/*
* 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 <fibril_sync.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 fibril_mutex_t dev_lock;
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, size_t size, void *buf);
static int file_bd_write(off_t blk_idx, size_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;
fibril_mutex_initialize(&dev_lock);
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;
size_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, size_t size, void *buf)
{
size_t n_rd;
fibril_mutex_lock(&dev_lock);
fseek(img
, blk_idx
* size
, SEEK_SET
); n_rd
= fread(buf
, 1, size
, img
);
fibril_mutex_unlock(&dev_lock);
return EIO; /* Read error */
}
fibril_mutex_unlock(&dev_lock);
if (n_rd < size)
return EINVAL; /* Read beyond end of disk */
return EOK;
}
static int file_bd_write(off_t blk_idx, size_t size, void *buf)
{
size_t n_wr;
fibril_mutex_lock(&dev_lock);
fseek(img
, blk_idx
* size
, SEEK_SET
); n_wr
= fread(buf
, 1, size
, img
);
if (ferror(img
) || n_wr
< size
) { fibril_mutex_unlock(&dev_lock);
return EIO; /* Write error */
}
fibril_mutex_unlock(&dev_lock);
return EOK;
}
/**
* @}
*/