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/*
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* QEMU System Emulator block driver
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*
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* Copyright (c) 2003 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "vl.h" |
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#ifndef _WIN32
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#include <sys/mman.h> |
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#endif
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#include "cow.h" |
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|
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struct BlockDriverState {
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int fd; /* if -1, only COW mappings */ |
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int64_t total_sectors; |
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int read_only; /* if true, the media is read only */ |
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int inserted; /* if true, the media is present */ |
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int removable; /* if true, the media can be removed */ |
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int locked; /* if true, the media cannot temporarily be ejected */ |
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/* event callback when inserting/removing */
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void (*change_cb)(void *opaque); |
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void *change_opaque;
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|
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uint8_t *cow_bitmap; /* if non NULL, COW mappings are used first */
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uint8_t *cow_bitmap_addr; /* mmap address of cow_bitmap */
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int cow_bitmap_size;
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int cow_fd;
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int64_t cow_sectors_offset; |
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int boot_sector_enabled;
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uint8_t boot_sector_data[512];
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|
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char filename[1024]; |
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|
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/* NOTE: the following infos are only hints for real hardware
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drivers. They are not used by the block driver */
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int cyls, heads, secs;
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int type;
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char device_name[32]; |
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BlockDriverState *next; |
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}; |
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static BlockDriverState *bdrv_first;
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/* create a new block device (by default it is empty) */
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BlockDriverState *bdrv_new(const char *device_name) |
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{ |
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BlockDriverState **pbs, *bs; |
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bs = qemu_mallocz(sizeof(BlockDriverState));
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if(!bs)
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return NULL; |
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pstrcpy(bs->device_name, sizeof(bs->device_name), device_name);
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/* insert at the end */
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pbs = &bdrv_first; |
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while (*pbs != NULL) |
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pbs = &(*pbs)->next; |
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*pbs = bs; |
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return bs;
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} |
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int bdrv_open(BlockDriverState *bs, const char *filename, int snapshot) |
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{ |
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int fd;
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int64_t size; |
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struct cow_header_v2 cow_header;
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#ifndef _WIN32
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char template[] = "/tmp/vl.XXXXXX"; |
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int cow_fd;
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struct stat st;
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#endif
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bs->read_only = 0;
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bs->fd = -1;
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bs->cow_fd = -1;
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bs->cow_bitmap = NULL;
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strcpy(bs->filename, filename); |
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/* open standard HD image */
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#ifdef _WIN32
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fd = open(filename, O_RDWR | O_BINARY); |
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#else
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fd = open(filename, O_RDWR | O_LARGEFILE); |
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#endif
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if (fd < 0) { |
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/* read only image on disk */
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#ifdef _WIN32
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fd = open(filename, O_RDONLY | O_BINARY); |
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#else
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fd = open(filename, O_RDONLY | O_LARGEFILE); |
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#endif
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if (fd < 0) { |
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perror(filename); |
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goto fail;
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} |
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if (!snapshot)
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bs->read_only = 1;
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} |
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bs->fd = fd; |
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/* see if it is a cow image */
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if (read(fd, &cow_header, sizeof(cow_header)) != sizeof(cow_header)) { |
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fprintf(stderr, "%s: could not read header\n", filename);
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goto fail;
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} |
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#ifndef _WIN32
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if (be32_to_cpu(cow_header.magic) == COW_MAGIC &&
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be32_to_cpu(cow_header.version) == COW_VERSION) { |
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/* cow image found */
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size = cow_header.size; |
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#ifndef WORDS_BIGENDIAN
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size = bswap64(size); |
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#endif
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bs->total_sectors = size / 512;
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bs->cow_fd = fd; |
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bs->fd = -1;
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if (cow_header.backing_file[0] != '\0') { |
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if (stat(cow_header.backing_file, &st) != 0) { |
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fprintf(stderr, "%s: could not find original disk image '%s'\n", filename, cow_header.backing_file);
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goto fail;
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} |
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if (st.st_mtime != be32_to_cpu(cow_header.mtime)) {
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fprintf(stderr, "%s: original raw disk image '%s' does not match saved timestamp\n", filename, cow_header.backing_file);
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goto fail;
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} |
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fd = open(cow_header.backing_file, O_RDONLY | O_LARGEFILE); |
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if (fd < 0) |
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goto fail;
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bs->fd = fd; |
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} |
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/* mmap the bitmap */
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bs->cow_bitmap_size = ((bs->total_sectors + 7) >> 3) + sizeof(cow_header); |
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bs->cow_bitmap_addr = mmap(get_mmap_addr(bs->cow_bitmap_size), |
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bs->cow_bitmap_size, |
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PROT_READ | PROT_WRITE, |
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MAP_SHARED, bs->cow_fd, 0);
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if (bs->cow_bitmap_addr == MAP_FAILED)
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goto fail;
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bs->cow_bitmap = bs->cow_bitmap_addr + sizeof(cow_header);
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bs->cow_sectors_offset = (bs->cow_bitmap_size + 511) & ~511; |
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snapshot = 0;
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} else
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#endif
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{ |
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/* standard raw image */
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size = lseek64(fd, 0, SEEK_END);
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bs->total_sectors = size / 512;
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bs->fd = fd; |
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} |
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#ifndef _WIN32
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if (snapshot) {
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/* create a temporary COW file */
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cow_fd = mkstemp(template); |
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if (cow_fd < 0) |
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goto fail;
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bs->cow_fd = cow_fd; |
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unlink(template); |
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/* just need to allocate bitmap */
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bs->cow_bitmap_size = (bs->total_sectors + 7) >> 3; |
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bs->cow_bitmap_addr = mmap(get_mmap_addr(bs->cow_bitmap_size), |
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bs->cow_bitmap_size, |
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PROT_READ | PROT_WRITE, |
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MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); |
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if (bs->cow_bitmap_addr == MAP_FAILED)
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goto fail;
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bs->cow_bitmap = bs->cow_bitmap_addr; |
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bs->cow_sectors_offset = 0;
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} |
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#endif
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bs->inserted = 1;
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/* call the change callback */
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if (bs->change_cb)
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bs->change_cb(bs->change_opaque); |
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return 0; |
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fail:
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bdrv_close(bs); |
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return -1; |
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} |
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void bdrv_close(BlockDriverState *bs)
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{ |
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if (bs->inserted) {
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#ifndef _WIN32
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/* we unmap the mapping so that it is written to the COW file */
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if (bs->cow_bitmap_addr)
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munmap(bs->cow_bitmap_addr, bs->cow_bitmap_size); |
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#endif
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if (bs->cow_fd >= 0) |
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close(bs->cow_fd); |
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if (bs->fd >= 0) |
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close(bs->fd); |
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bs->inserted = 0;
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/* call the change callback */
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if (bs->change_cb)
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bs->change_cb(bs->change_opaque); |
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} |
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} |
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void bdrv_delete(BlockDriverState *bs)
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{ |
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bdrv_close(bs); |
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qemu_free(bs); |
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} |
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static inline void set_bit(uint8_t *bitmap, int64_t bitnum) |
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{ |
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bitmap[bitnum / 8] |= (1 << (bitnum%8)); |
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} |
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static inline int is_bit_set(const uint8_t *bitmap, int64_t bitnum) |
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{ |
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return !!(bitmap[bitnum / 8] & (1 << (bitnum%8))); |
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} |
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/* Return true if first block has been changed (ie. current version is
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* in COW file). Set the number of continuous blocks for which that
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* is true. */
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static int is_changed(uint8_t *bitmap, |
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int64_t sector_num, int nb_sectors,
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int *num_same)
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{ |
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int changed;
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if (!bitmap || nb_sectors == 0) { |
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*num_same = nb_sectors; |
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return 0; |
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} |
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changed = is_bit_set(bitmap, sector_num); |
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for (*num_same = 1; *num_same < nb_sectors; (*num_same)++) { |
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if (is_bit_set(bitmap, sector_num + *num_same) != changed)
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break;
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} |
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return changed;
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} |
263 |
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/* commit COW file into the raw image */
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int bdrv_commit(BlockDriverState *bs)
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{ |
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int64_t i; |
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uint8_t *cow_bitmap; |
269 |
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if (!bs->inserted)
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return -1; |
272 |
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if (!bs->cow_bitmap) {
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fprintf(stderr, "Already committed to %s\n", bs->filename);
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return 0; |
276 |
} |
277 |
|
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if (bs->read_only) {
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fprintf(stderr, "Can't commit to %s: read-only\n", bs->filename);
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return -1; |
281 |
} |
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cow_bitmap = bs->cow_bitmap; |
284 |
for (i = 0; i < bs->total_sectors; i++) { |
285 |
if (is_bit_set(cow_bitmap, i)) {
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unsigned char sector[512]; |
287 |
if (bdrv_read(bs, i, sector, 1) != 0) { |
288 |
fprintf(stderr, "Error reading sector %lli: aborting commit\n",
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(long long)i); |
290 |
return -1; |
291 |
} |
292 |
|
293 |
/* Make bdrv_write write to real file for a moment. */
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bs->cow_bitmap = NULL;
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if (bdrv_write(bs, i, sector, 1) != 0) { |
296 |
fprintf(stderr, "Error writing sector %lli: aborting commit\n",
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297 |
(long long)i); |
298 |
bs->cow_bitmap = cow_bitmap; |
299 |
return -1; |
300 |
} |
301 |
bs->cow_bitmap = cow_bitmap; |
302 |
} |
303 |
} |
304 |
fprintf(stderr, "Committed snapshot to %s\n", bs->filename);
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305 |
return 0; |
306 |
} |
307 |
|
308 |
/* return -1 if error */
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309 |
int bdrv_read(BlockDriverState *bs, int64_t sector_num,
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310 |
uint8_t *buf, int nb_sectors)
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311 |
{ |
312 |
int ret, n, fd;
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313 |
int64_t offset; |
314 |
|
315 |
if (!bs->inserted)
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316 |
return -1; |
317 |
|
318 |
while (nb_sectors > 0) { |
319 |
if (is_changed(bs->cow_bitmap, sector_num, nb_sectors, &n)) {
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320 |
fd = bs->cow_fd; |
321 |
offset = bs->cow_sectors_offset; |
322 |
} else if (sector_num == 0 && bs->boot_sector_enabled) { |
323 |
memcpy(buf, bs->boot_sector_data, 512);
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324 |
n = 1;
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325 |
goto next;
|
326 |
} else {
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327 |
fd = bs->fd; |
328 |
offset = 0;
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329 |
} |
330 |
|
331 |
if (fd < 0) { |
332 |
/* no file, just return empty sectors */
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333 |
memset(buf, 0, n * 512); |
334 |
} else {
|
335 |
offset += sector_num * 512;
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336 |
lseek64(fd, offset, SEEK_SET); |
337 |
ret = read(fd, buf, n * 512);
|
338 |
if (ret != n * 512) { |
339 |
return -1; |
340 |
} |
341 |
} |
342 |
next:
|
343 |
nb_sectors -= n; |
344 |
sector_num += n; |
345 |
buf += n * 512;
|
346 |
} |
347 |
return 0; |
348 |
} |
349 |
|
350 |
/* return -1 if error */
|
351 |
int bdrv_write(BlockDriverState *bs, int64_t sector_num,
|
352 |
const uint8_t *buf, int nb_sectors) |
353 |
{ |
354 |
int ret, fd, i;
|
355 |
int64_t offset, retl; |
356 |
|
357 |
if (!bs->inserted)
|
358 |
return -1; |
359 |
if (bs->read_only)
|
360 |
return -1; |
361 |
|
362 |
if (bs->cow_bitmap) {
|
363 |
fd = bs->cow_fd; |
364 |
offset = bs->cow_sectors_offset; |
365 |
} else {
|
366 |
fd = bs->fd; |
367 |
offset = 0;
|
368 |
} |
369 |
|
370 |
offset += sector_num * 512;
|
371 |
retl = lseek64(fd, offset, SEEK_SET); |
372 |
if (retl == -1) { |
373 |
return -1; |
374 |
} |
375 |
ret = write(fd, buf, nb_sectors * 512);
|
376 |
if (ret != nb_sectors * 512) { |
377 |
return -1; |
378 |
} |
379 |
|
380 |
if (bs->cow_bitmap) {
|
381 |
for (i = 0; i < nb_sectors; i++) |
382 |
set_bit(bs->cow_bitmap, sector_num + i); |
383 |
} |
384 |
return 0; |
385 |
} |
386 |
|
387 |
void bdrv_get_geometry(BlockDriverState *bs, int64_t *nb_sectors_ptr)
|
388 |
{ |
389 |
*nb_sectors_ptr = bs->total_sectors; |
390 |
} |
391 |
|
392 |
/* force a given boot sector. */
|
393 |
void bdrv_set_boot_sector(BlockDriverState *bs, const uint8_t *data, int size) |
394 |
{ |
395 |
bs->boot_sector_enabled = 1;
|
396 |
if (size > 512) |
397 |
size = 512;
|
398 |
memcpy(bs->boot_sector_data, data, size); |
399 |
memset(bs->boot_sector_data + size, 0, 512 - size); |
400 |
} |
401 |
|
402 |
void bdrv_set_geometry_hint(BlockDriverState *bs,
|
403 |
int cyls, int heads, int secs) |
404 |
{ |
405 |
bs->cyls = cyls; |
406 |
bs->heads = heads; |
407 |
bs->secs = secs; |
408 |
} |
409 |
|
410 |
void bdrv_set_type_hint(BlockDriverState *bs, int type) |
411 |
{ |
412 |
bs->type = type; |
413 |
bs->removable = ((type == BDRV_TYPE_CDROM || |
414 |
type == BDRV_TYPE_FLOPPY)); |
415 |
} |
416 |
|
417 |
void bdrv_get_geometry_hint(BlockDriverState *bs,
|
418 |
int *pcyls, int *pheads, int *psecs) |
419 |
{ |
420 |
*pcyls = bs->cyls; |
421 |
*pheads = bs->heads; |
422 |
*psecs = bs->secs; |
423 |
} |
424 |
|
425 |
int bdrv_get_type_hint(BlockDriverState *bs)
|
426 |
{ |
427 |
return bs->type;
|
428 |
} |
429 |
|
430 |
int bdrv_is_removable(BlockDriverState *bs)
|
431 |
{ |
432 |
return bs->removable;
|
433 |
} |
434 |
|
435 |
int bdrv_is_read_only(BlockDriverState *bs)
|
436 |
{ |
437 |
return bs->read_only;
|
438 |
} |
439 |
|
440 |
int bdrv_is_inserted(BlockDriverState *bs)
|
441 |
{ |
442 |
return bs->inserted;
|
443 |
} |
444 |
|
445 |
int bdrv_is_locked(BlockDriverState *bs)
|
446 |
{ |
447 |
return bs->locked;
|
448 |
} |
449 |
|
450 |
void bdrv_set_locked(BlockDriverState *bs, int locked) |
451 |
{ |
452 |
bs->locked = locked; |
453 |
} |
454 |
|
455 |
void bdrv_set_change_cb(BlockDriverState *bs,
|
456 |
void (*change_cb)(void *opaque), void *opaque) |
457 |
{ |
458 |
bs->change_cb = change_cb; |
459 |
bs->change_opaque = opaque; |
460 |
} |
461 |
|
462 |
BlockDriverState *bdrv_find(const char *name) |
463 |
{ |
464 |
BlockDriverState *bs; |
465 |
|
466 |
for (bs = bdrv_first; bs != NULL; bs = bs->next) { |
467 |
if (!strcmp(name, bs->device_name))
|
468 |
return bs;
|
469 |
} |
470 |
return NULL; |
471 |
} |
472 |
|
473 |
void bdrv_info(void) |
474 |
{ |
475 |
BlockDriverState *bs; |
476 |
|
477 |
for (bs = bdrv_first; bs != NULL; bs = bs->next) { |
478 |
term_printf("%s:", bs->device_name);
|
479 |
term_printf(" type=");
|
480 |
switch(bs->type) {
|
481 |
case BDRV_TYPE_HD:
|
482 |
term_printf("hd");
|
483 |
break;
|
484 |
case BDRV_TYPE_CDROM:
|
485 |
term_printf("cdrom");
|
486 |
break;
|
487 |
case BDRV_TYPE_FLOPPY:
|
488 |
term_printf("floppy");
|
489 |
break;
|
490 |
} |
491 |
term_printf(" removable=%d", bs->removable);
|
492 |
if (bs->removable) {
|
493 |
term_printf(" locked=%d", bs->locked);
|
494 |
} |
495 |
if (bs->inserted) {
|
496 |
term_printf(" file=%s", bs->filename);
|
497 |
term_printf(" ro=%d", bs->read_only);
|
498 |
} else {
|
499 |
term_printf(" [not inserted]");
|
500 |
} |
501 |
term_printf("\n");
|
502 |
} |
503 |
} |