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; |
} |
|
/** |
* @} |
*/ |