| 0,0 → 1,217 |
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| /* |
| * 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; |
| } |
| |
| /** |
| * @} |
| */ |