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xemu/qemu-img.c
Kevin Wolf 3e85c6fd71 qemu-img rebase 
This adds a rebase subcommand to qemu-img which allows to change the backing
file of an image.

In default mode, both the current and the new backing file need to exist, and
after the rebase, the COW image is guaranteed to have the same guest visible
content as before. To achieve this, old and new backing file are compared and,
if necessary, data is copied from the old backing file into the COW image.

With -u an unsafe mode is enabled that doesn't require the backing files to
exist. It merely changes the backing file reference in the COW image. This is
useful for renaming or moving the backing file. The user is responsible to make
sure that the new backing file has no changes compared to the old one, or
corruption may occur.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-13 17:14:15 -06:00

1292 lines
36 KiB
C
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/*
* QEMU disk image utility
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu-common.h"
#include "qemu-option.h"
#include "osdep.h"
#include "block_int.h"
#include <stdio.h>
#ifdef _WIN32
#include <windows.h>
#endif
typedef struct img_cmd_t {
const char *name;
int (*handler)(int argc, char **argv);
} img_cmd_t;
/* Default to cache=writeback as data integrity is not important for qemu-tcg. */
#define BRDV_O_FLAGS BDRV_O_CACHE_WB
static void QEMU_NORETURN error(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
fprintf(stderr, "qemu-img: ");
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
exit(1);
va_end(ap);
}
static void format_print(void *opaque, const char *name)
{
printf(" %s", name);
}
/* Please keep in synch with qemu-img.texi */
static void help(void)
{
printf("qemu-img version " QEMU_VERSION ", Copyright (c) 2004-2008 Fabrice Bellard\n"
"usage: qemu-img command [command options]\n"
"QEMU disk image utility\n"
"\n"
"Command syntax:\n"
#define DEF(option, callback, arg_string) \
" " arg_string "\n"
#include "qemu-img-cmds.h"
#undef DEF
#undef GEN_DOCS
"\n"
"Command parameters:\n"
" 'filename' is a disk image filename\n"
" 'fmt' is the disk image format. It is guessed automatically in most cases\n"
" 'size' is the disk image size in bytes. Optional suffixes\n"
" 'k' or 'K' (kilobyte, 1024), 'M' (megabyte, 1024k), 'G' (gigabyte, 1024M)\n"
" and T (terabyte, 1024G) are supported. 'b' is ignored.\n"
" 'output_filename' is the destination disk image filename\n"
" 'output_fmt' is the destination format\n"
" 'options' is a comma separated list of format specific options in a\n"
" name=value format. Use -o ? for an overview of the options supported by the\n"
" used format\n"
" '-c' indicates that target image must be compressed (qcow format only)\n"
" '-u' enables unsafe rebasing. It is assumed that old and new backing file\n"
" match exactly. The image doesn't need a working backing file before\n"
" rebasing in this case (useful for renaming the backing file)\n"
" '-h' with or without a command shows this help and lists the supported formats\n"
"\n"
"Parameters to snapshot subcommand:\n"
" 'snapshot' is the name of the snapshot to create, apply or delete\n"
" '-a' applies a snapshot (revert disk to saved state)\n"
" '-c' creates a snapshot\n"
" '-d' deletes a snapshot\n"
" '-l' lists all snapshots in the given image\n"
);
printf("\nSupported formats:");
bdrv_iterate_format(format_print, NULL);
printf("\n");
exit(1);
}
#if defined(WIN32)
/* XXX: put correct support for win32 */
static int read_password(char *buf, int buf_size)
{
int c, i;
printf("Password: ");
fflush(stdout);
i = 0;
for(;;) {
c = getchar();
if (c == '\n')
break;
if (i < (buf_size - 1))
buf[i++] = c;
}
buf[i] = '\0';
return 0;
}
#else
#include <termios.h>
static struct termios oldtty;
static void term_exit(void)
{
tcsetattr (0, TCSANOW, &oldtty);
}
static void term_init(void)
{
struct termios tty;
tcgetattr (0, &tty);
oldtty = tty;
tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
|INLCR|IGNCR|ICRNL|IXON);
tty.c_oflag |= OPOST;
tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);
tty.c_cflag &= ~(CSIZE|PARENB);
tty.c_cflag |= CS8;
tty.c_cc[VMIN] = 1;
tty.c_cc[VTIME] = 0;
tcsetattr (0, TCSANOW, &tty);
atexit(term_exit);
}
static int read_password(char *buf, int buf_size)
{
uint8_t ch;
int i, ret;
printf("password: ");
fflush(stdout);
term_init();
i = 0;
for(;;) {
ret = read(0, &ch, 1);
if (ret == -1) {
if (errno == EAGAIN || errno == EINTR) {
continue;
} else {
ret = -1;
break;
}
} else if (ret == 0) {
ret = -1;
break;
} else {
if (ch == '\r') {
ret = 0;
break;
}
if (i < (buf_size - 1))
buf[i++] = ch;
}
}
term_exit();
buf[i] = '\0';
printf("\n");
return ret;
}
#endif
static BlockDriverState *bdrv_new_open(const char *filename,
const char *fmt)
{
BlockDriverState *bs;
BlockDriver *drv;
char password[256];
bs = bdrv_new("");
if (!bs)
error("Not enough memory");
if (fmt) {
drv = bdrv_find_format(fmt);
if (!drv)
error("Unknown file format '%s'", fmt);
} else {
drv = NULL;
}
if (bdrv_open2(bs, filename, BRDV_O_FLAGS, drv) < 0) {
error("Could not open '%s'", filename);
}
if (bdrv_is_encrypted(bs)) {
printf("Disk image '%s' is encrypted.\n", filename);
if (read_password(password, sizeof(password)) < 0)
error("No password given");
if (bdrv_set_key(bs, password) < 0)
error("invalid password");
}
return bs;
}
static void add_old_style_options(const char *fmt, QEMUOptionParameter *list,
int flags, const char *base_filename, const char *base_fmt)
{
if (flags & BLOCK_FLAG_ENCRYPT) {
if (set_option_parameter(list, BLOCK_OPT_ENCRYPT, "on")) {
error("Encryption not supported for file format '%s'", fmt);
}
}
if (flags & BLOCK_FLAG_COMPAT6) {
if (set_option_parameter(list, BLOCK_OPT_COMPAT6, "on")) {
error("VMDK version 6 not supported for file format '%s'", fmt);
}
}
if (base_filename) {
if (set_option_parameter(list, BLOCK_OPT_BACKING_FILE, base_filename)) {
error("Backing file not supported for file format '%s'", fmt);
}
}
if (base_fmt) {
if (set_option_parameter(list, BLOCK_OPT_BACKING_FMT, base_fmt)) {
error("Backing file format not supported for file format '%s'", fmt);
}
}
}
static int img_create(int argc, char **argv)
{
int c, ret, flags;
const char *fmt = "raw";
const char *base_fmt = NULL;
const char *filename;
const char *base_filename = NULL;
BlockDriver *drv;
QEMUOptionParameter *param = NULL;
char *options = NULL;
flags = 0;
for(;;) {
c = getopt(argc, argv, "F:b:f:he6o:");
if (c == -1)
break;
switch(c) {
case 'h':
help();
break;
case 'F':
base_fmt = optarg;
break;
case 'b':
base_filename = optarg;
break;
case 'f':
fmt = optarg;
break;
case 'e':
flags |= BLOCK_FLAG_ENCRYPT;
break;
case '6':
flags |= BLOCK_FLAG_COMPAT6;
break;
case 'o':
options = optarg;
break;
}
}
/* Find driver and parse its options */
drv = bdrv_find_format(fmt);
if (!drv)
error("Unknown file format '%s'", fmt);
if (options && !strcmp(options, "?")) {
print_option_help(drv->create_options);
return 0;
}
/* Create parameter list with default values */
param = parse_option_parameters("", drv->create_options, param);
set_option_parameter_int(param, BLOCK_OPT_SIZE, -1);
/* Parse -o options */
if (options) {
param = parse_option_parameters(options, drv->create_options, param);
if (param == NULL) {
error("Invalid options for file format '%s'.", fmt);
}
}
/* Get the filename */
if (optind >= argc)
help();
filename = argv[optind++];
/* Add size to parameters */
if (optind < argc) {
set_option_parameter(param, BLOCK_OPT_SIZE, argv[optind++]);
}
/* Add old-style options to parameters */
add_old_style_options(fmt, param, flags, base_filename, base_fmt);
// The size for the image must always be specified, with one exception:
// If we are using a backing file, we can obtain the size from there
if (get_option_parameter(param, BLOCK_OPT_SIZE)->value.n == -1) {
QEMUOptionParameter *backing_file =
get_option_parameter(param, BLOCK_OPT_BACKING_FILE);
QEMUOptionParameter *backing_fmt =
get_option_parameter(param, BLOCK_OPT_BACKING_FMT);
if (backing_file && backing_file->value.s) {
BlockDriverState *bs;
uint64_t size;
const char *fmt = NULL;
char buf[32];
if (backing_fmt && backing_fmt->value.s) {
if (bdrv_find_format(backing_fmt->value.s)) {
fmt = backing_fmt->value.s;
} else {
error("Unknown backing file format '%s'",
backing_fmt->value.s);
}
}
bs = bdrv_new_open(backing_file->value.s, fmt);
bdrv_get_geometry(bs, &size);
size *= 512;
bdrv_delete(bs);
snprintf(buf, sizeof(buf), "%" PRId64, size);
set_option_parameter(param, BLOCK_OPT_SIZE, buf);
} else {
error("Image creation needs a size parameter");
}
}
printf("Formatting '%s', fmt=%s ", filename, fmt);
print_option_parameters(param);
puts("");
ret = bdrv_create(drv, filename, param);
free_option_parameters(param);
if (ret < 0) {
if (ret == -ENOTSUP) {
error("Formatting or formatting option not supported for file format '%s'", fmt);
} else if (ret == -EFBIG) {
error("The image size is too large for file format '%s'", fmt);
} else {
error("Error while formatting");
}
}
return 0;
}
static int img_check(int argc, char **argv)
{
int c, ret;
const char *filename, *fmt;
BlockDriver *drv;
BlockDriverState *bs;
fmt = NULL;
for(;;) {
c = getopt(argc, argv, "f:h");
if (c == -1)
break;
switch(c) {
case 'h':
help();
break;
case 'f':
fmt = optarg;
break;
}
}
if (optind >= argc)
help();
filename = argv[optind++];
bs = bdrv_new("");
if (!bs)
error("Not enough memory");
if (fmt) {
drv = bdrv_find_format(fmt);
if (!drv)
error("Unknown file format '%s'", fmt);
} else {
drv = NULL;
}
if (bdrv_open2(bs, filename, BRDV_O_FLAGS, drv) < 0) {
error("Could not open '%s'", filename);
}
ret = bdrv_check(bs);
switch(ret) {
case 0:
printf("No errors were found on the image.\n");
break;
case -ENOTSUP:
error("This image format does not support checks");
break;
default:
if (ret < 0) {
error("An error occurred during the check");
} else {
printf("%d errors were found on the image.\n", ret);
}
break;
}
bdrv_delete(bs);
return 0;
}
static int img_commit(int argc, char **argv)
{
int c, ret;
const char *filename, *fmt;
BlockDriver *drv;
BlockDriverState *bs;
fmt = NULL;
for(;;) {
c = getopt(argc, argv, "f:h");
if (c == -1)
break;
switch(c) {
case 'h':
help();
break;
case 'f':
fmt = optarg;
break;
}
}
if (optind >= argc)
help();
filename = argv[optind++];
bs = bdrv_new("");
if (!bs)
error("Not enough memory");
if (fmt) {
drv = bdrv_find_format(fmt);
if (!drv)
error("Unknown file format '%s'", fmt);
} else {
drv = NULL;
}
if (bdrv_open2(bs, filename, BRDV_O_FLAGS, drv) < 0) {
error("Could not open '%s'", filename);
}
ret = bdrv_commit(bs);
switch(ret) {
case 0:
printf("Image committed.\n");
break;
case -ENOENT:
error("No disk inserted");
break;
case -EACCES:
error("Image is read-only");
break;
case -ENOTSUP:
error("Image is already committed");
break;
default:
error("Error while committing image");
break;
}
bdrv_delete(bs);
return 0;
}
static int is_not_zero(const uint8_t *sector, int len)
{
int i;
len >>= 2;
for(i = 0;i < len; i++) {
if (((uint32_t *)sector)[i] != 0)
return 1;
}
return 0;
}
/*
* Returns true iff the first sector pointed to by 'buf' contains at least
* a non-NUL byte.
*
* 'pnum' is set to the number of sectors (including and immediately following
* the first one) that are known to be in the same allocated/unallocated state.
*/
static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum)
{
int v, i;
if (n <= 0) {
*pnum = 0;
return 0;
}
v = is_not_zero(buf, 512);
for(i = 1; i < n; i++) {
buf += 512;
if (v != is_not_zero(buf, 512))
break;
}
*pnum = i;
return v;
}
/*
* Compares two buffers sector by sector. Returns 0 if the first sector of both
* buffers matches, non-zero otherwise.
*
* pnum is set to the number of sectors (including and immediately following
* the first one) that are known to have the same comparison result
*/
static int compare_sectors(const uint8_t *buf1, const uint8_t *buf2, int n,
int *pnum)
{
int res, i;
if (n <= 0) {
*pnum = 0;
return 0;
}
res = !!memcmp(buf1, buf2, 512);
for(i = 1; i < n; i++) {
buf1 += 512;
buf2 += 512;
if (!!memcmp(buf1, buf2, 512) != res) {
break;
}
}
*pnum = i;
return res;
}
#define IO_BUF_SIZE (2 * 1024 * 1024)
static int img_convert(int argc, char **argv)
{
int c, ret, n, n1, bs_n, bs_i, flags, cluster_size, cluster_sectors;
const char *fmt, *out_fmt, *out_baseimg, *out_filename;
BlockDriver *drv;
BlockDriverState **bs, *out_bs;
int64_t total_sectors, nb_sectors, sector_num, bs_offset;
uint64_t bs_sectors;
uint8_t buf[IO_BUF_SIZE];
const uint8_t *buf1;
BlockDriverInfo bdi;
QEMUOptionParameter *param = NULL;
char *options = NULL;
fmt = NULL;
out_fmt = "raw";
out_baseimg = NULL;
flags = 0;
for(;;) {
c = getopt(argc, argv, "f:O:B:hce6o:");
if (c == -1)
break;
switch(c) {
case 'h':
help();
break;
case 'f':
fmt = optarg;
break;
case 'O':
out_fmt = optarg;
break;
case 'B':
out_baseimg = optarg;
break;
case 'c':
flags |= BLOCK_FLAG_COMPRESS;
break;
case 'e':
flags |= BLOCK_FLAG_ENCRYPT;
break;
case '6':
flags |= BLOCK_FLAG_COMPAT6;
break;
case 'o':
options = optarg;
break;
}
}
bs_n = argc - optind - 1;
if (bs_n < 1) help();
out_filename = argv[argc - 1];
if (bs_n > 1 && out_baseimg)
error("-B makes no sense when concatenating multiple input images");
bs = calloc(bs_n, sizeof(BlockDriverState *));
if (!bs)
error("Out of memory");
total_sectors = 0;
for (bs_i = 0; bs_i < bs_n; bs_i++) {
bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt);
if (!bs[bs_i])
error("Could not open '%s'", argv[optind + bs_i]);
bdrv_get_geometry(bs[bs_i], &bs_sectors);
total_sectors += bs_sectors;
}
/* Find driver and parse its options */
drv = bdrv_find_format(out_fmt);
if (!drv)
error("Unknown file format '%s'", out_fmt);
if (options && !strcmp(options, "?")) {
print_option_help(drv->create_options);
free(bs);
return 0;
}
if (options) {
param = parse_option_parameters(options, drv->create_options, param);
if (param == NULL) {
error("Invalid options for file format '%s'.", out_fmt);
}
} else {
param = parse_option_parameters("", drv->create_options, param);
}
set_option_parameter_int(param, BLOCK_OPT_SIZE, total_sectors * 512);
add_old_style_options(out_fmt, param, flags, out_baseimg, NULL);
/* Check if compression is supported */
if (flags & BLOCK_FLAG_COMPRESS) {
QEMUOptionParameter *encryption =
get_option_parameter(param, BLOCK_OPT_ENCRYPT);
if (!drv->bdrv_write_compressed) {
error("Compression not supported for this file format");
}
if (encryption && encryption->value.n) {
error("Compression and encryption not supported at the same time");
}
}
/* Create the new image */
ret = bdrv_create(drv, out_filename, param);
free_option_parameters(param);
if (ret < 0) {
if (ret == -ENOTSUP) {
error("Formatting not supported for file format '%s'", out_fmt);
} else if (ret == -EFBIG) {
error("The image size is too large for file format '%s'", out_fmt);
} else {
error("Error while formatting '%s'", out_filename);
}
}
out_bs = bdrv_new_open(out_filename, out_fmt);
bs_i = 0;
bs_offset = 0;
bdrv_get_geometry(bs[0], &bs_sectors);
if (flags & BLOCK_FLAG_COMPRESS) {
if (bdrv_get_info(out_bs, &bdi) < 0)
error("could not get block driver info");
cluster_size = bdi.cluster_size;
if (cluster_size <= 0 || cluster_size > IO_BUF_SIZE)
error("invalid cluster size");
cluster_sectors = cluster_size >> 9;
sector_num = 0;
for(;;) {
int64_t bs_num;
int remainder;
uint8_t *buf2;
nb_sectors = total_sectors - sector_num;
if (nb_sectors <= 0)
break;
if (nb_sectors >= cluster_sectors)
n = cluster_sectors;
else
n = nb_sectors;
bs_num = sector_num - bs_offset;
assert (bs_num >= 0);
remainder = n;
buf2 = buf;
while (remainder > 0) {
int nlow;
while (bs_num == bs_sectors) {
bs_i++;
assert (bs_i < bs_n);
bs_offset += bs_sectors;
bdrv_get_geometry(bs[bs_i], &bs_sectors);
bs_num = 0;
/* printf("changing part: sector_num=%lld, "
"bs_i=%d, bs_offset=%lld, bs_sectors=%lld\n",
sector_num, bs_i, bs_offset, bs_sectors); */
}
assert (bs_num < bs_sectors);
nlow = (remainder > bs_sectors - bs_num) ? bs_sectors - bs_num : remainder;
if (bdrv_read(bs[bs_i], bs_num, buf2, nlow) < 0)
error("error while reading");
buf2 += nlow * 512;
bs_num += nlow;
remainder -= nlow;
}
assert (remainder == 0);
if (n < cluster_sectors)
memset(buf + n * 512, 0, cluster_size - n * 512);
if (is_not_zero(buf, cluster_size)) {
if (bdrv_write_compressed(out_bs, sector_num, buf,
cluster_sectors) != 0)
error("error while compressing sector %" PRId64,
sector_num);
}
sector_num += n;
}
/* signal EOF to align */
bdrv_write_compressed(out_bs, 0, NULL, 0);
} else {
sector_num = 0; // total number of sectors converted so far
for(;;) {
nb_sectors = total_sectors - sector_num;
if (nb_sectors <= 0)
break;
if (nb_sectors >= (IO_BUF_SIZE / 512))
n = (IO_BUF_SIZE / 512);
else
n = nb_sectors;
while (sector_num - bs_offset >= bs_sectors) {
bs_i ++;
assert (bs_i < bs_n);
bs_offset += bs_sectors;
bdrv_get_geometry(bs[bs_i], &bs_sectors);
/* printf("changing part: sector_num=%lld, bs_i=%d, "
"bs_offset=%lld, bs_sectors=%lld\n",
sector_num, bs_i, bs_offset, bs_sectors); */
}
if (n > bs_offset + bs_sectors - sector_num)
n = bs_offset + bs_sectors - sector_num;
if (!drv->no_zero_init) {
/* If the output image is being created as a copy on write image,
assume that sectors which are unallocated in the input image
are present in both the output's and input's base images (no
need to copy them). */
if (out_baseimg) {
if (!bdrv_is_allocated(bs[bs_i], sector_num - bs_offset,
n, &n1)) {
sector_num += n1;
continue;
}
/* The next 'n1' sectors are allocated in the input image. Copy
only those as they may be followed by unallocated sectors. */
n = n1;
}
} else {
n1 = n;
}
if (bdrv_read(bs[bs_i], sector_num - bs_offset, buf, n) < 0)
error("error while reading");
/* NOTE: at the same time we convert, we do not write zero
sectors to have a chance to compress the image. Ideally, we
should add a specific call to have the info to go faster */
buf1 = buf;
while (n > 0) {
/* If the output image is being created as a copy on write image,
copy all sectors even the ones containing only NUL bytes,
because they may differ from the sectors in the base image.
If the output is to a host device, we also write out
sectors that are entirely 0, since whatever data was
already there is garbage, not 0s. */
if (drv->no_zero_init || out_baseimg ||
is_allocated_sectors(buf1, n, &n1)) {
if (bdrv_write(out_bs, sector_num, buf1, n1) < 0)
error("error while writing");
}
sector_num += n1;
n -= n1;
buf1 += n1 * 512;
}
}
}
bdrv_delete(out_bs);
for (bs_i = 0; bs_i < bs_n; bs_i++)
bdrv_delete(bs[bs_i]);
free(bs);
return 0;
}
#ifdef _WIN32
static int64_t get_allocated_file_size(const char *filename)
{
typedef DWORD (WINAPI * get_compressed_t)(const char *filename, DWORD *high);
get_compressed_t get_compressed;
struct _stati64 st;
/* WinNT support GetCompressedFileSize to determine allocate size */
get_compressed = (get_compressed_t) GetProcAddress(GetModuleHandle("kernel32"), "GetCompressedFileSizeA");
if (get_compressed) {
DWORD high, low;
low = get_compressed(filename, &high);
if (low != 0xFFFFFFFFlu || GetLastError() == NO_ERROR)
return (((int64_t) high) << 32) + low;
}
if (_stati64(filename, &st) < 0)
return -1;
return st.st_size;
}
#else
static int64_t get_allocated_file_size(const char *filename)
{
struct stat st;
if (stat(filename, &st) < 0)
return -1;
return (int64_t)st.st_blocks * 512;
}
#endif
static void dump_snapshots(BlockDriverState *bs)
{
QEMUSnapshotInfo *sn_tab, *sn;
int nb_sns, i;
char buf[256];
nb_sns = bdrv_snapshot_list(bs, &sn_tab);
if (nb_sns <= 0)
return;
printf("Snapshot list:\n");
printf("%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL));
for(i = 0; i < nb_sns; i++) {
sn = &sn_tab[i];
printf("%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn));
}
qemu_free(sn_tab);
}
static int img_info(int argc, char **argv)
{
int c;
const char *filename, *fmt;
BlockDriver *drv;
BlockDriverState *bs;
char fmt_name[128], size_buf[128], dsize_buf[128];
uint64_t total_sectors;
int64_t allocated_size;
char backing_filename[1024];
char backing_filename2[1024];
BlockDriverInfo bdi;
fmt = NULL;
for(;;) {
c = getopt(argc, argv, "f:h");
if (c == -1)
break;
switch(c) {
case 'h':
help();
break;
case 'f':
fmt = optarg;
break;
}
}
if (optind >= argc)
help();
filename = argv[optind++];
bs = bdrv_new("");
if (!bs)
error("Not enough memory");
if (fmt) {
drv = bdrv_find_format(fmt);
if (!drv)
error("Unknown file format '%s'", fmt);
} else {
drv = NULL;
}
if (bdrv_open2(bs, filename, BRDV_O_FLAGS | BDRV_O_NO_BACKING, drv) < 0) {
error("Could not open '%s'", filename);
}
bdrv_get_format(bs, fmt_name, sizeof(fmt_name));
bdrv_get_geometry(bs, &total_sectors);
get_human_readable_size(size_buf, sizeof(size_buf), total_sectors * 512);
allocated_size = get_allocated_file_size(filename);
if (allocated_size < 0)
snprintf(dsize_buf, sizeof(dsize_buf), "unavailable");
else
get_human_readable_size(dsize_buf, sizeof(dsize_buf),
allocated_size);
printf("image: %s\n"
"file format: %s\n"
"virtual size: %s (%" PRId64 " bytes)\n"
"disk size: %s\n",
filename, fmt_name, size_buf,
(total_sectors * 512),
dsize_buf);
if (bdrv_is_encrypted(bs))
printf("encrypted: yes\n");
if (bdrv_get_info(bs, &bdi) >= 0) {
if (bdi.cluster_size != 0)
printf("cluster_size: %d\n", bdi.cluster_size);
}
bdrv_get_backing_filename(bs, backing_filename, sizeof(backing_filename));
if (backing_filename[0] != '\0') {
path_combine(backing_filename2, sizeof(backing_filename2),
filename, backing_filename);
printf("backing file: %s (actual path: %s)\n",
backing_filename,
backing_filename2);
}
dump_snapshots(bs);
bdrv_delete(bs);
return 0;
}
#define SNAPSHOT_LIST 1
#define SNAPSHOT_CREATE 2
#define SNAPSHOT_APPLY 3
#define SNAPSHOT_DELETE 4
static int img_snapshot(int argc, char **argv)
{
BlockDriverState *bs;
QEMUSnapshotInfo sn;
char *filename, *snapshot_name = NULL;
int c, ret;
int action = 0;
qemu_timeval tv;
/* Parse commandline parameters */
for(;;) {
c = getopt(argc, argv, "la:c:d:h");
if (c == -1)
break;
switch(c) {
case 'h':
help();
return 0;
case 'l':
if (action) {
help();
return 0;
}
action = SNAPSHOT_LIST;
break;
case 'a':
if (action) {
help();
return 0;
}
action = SNAPSHOT_APPLY;
snapshot_name = optarg;
break;
case 'c':
if (action) {
help();
return 0;
}
action = SNAPSHOT_CREATE;
snapshot_name = optarg;
break;
case 'd':
if (action) {
help();
return 0;
}
action = SNAPSHOT_DELETE;
snapshot_name = optarg;
break;
}
}
if (optind >= argc)
help();
filename = argv[optind++];
/* Open the image */
bs = bdrv_new("");
if (!bs)
error("Not enough memory");
if (bdrv_open2(bs, filename, 0, NULL) < 0) {
error("Could not open '%s'", filename);
}
/* Perform the requested action */
switch(action) {
case SNAPSHOT_LIST:
dump_snapshots(bs);
break;
case SNAPSHOT_CREATE:
memset(&sn, 0, sizeof(sn));
pstrcpy(sn.name, sizeof(sn.name), snapshot_name);
qemu_gettimeofday(&tv);
sn.date_sec = tv.tv_sec;
sn.date_nsec = tv.tv_usec * 1000;
ret = bdrv_snapshot_create(bs, &sn);
if (ret)
error("Could not create snapshot '%s': %d (%s)",
snapshot_name, ret, strerror(-ret));
break;
case SNAPSHOT_APPLY:
ret = bdrv_snapshot_goto(bs, snapshot_name);
if (ret)
error("Could not apply snapshot '%s': %d (%s)",
snapshot_name, ret, strerror(-ret));
break;
case SNAPSHOT_DELETE:
ret = bdrv_snapshot_delete(bs, snapshot_name);
if (ret)
error("Could not delete snapshot '%s': %d (%s)",
snapshot_name, ret, strerror(-ret));
break;
}
/* Cleanup */
bdrv_delete(bs);
return 0;
}
static int img_rebase(int argc, char **argv)
{
BlockDriverState *bs, *bs_old_backing, *bs_new_backing;
BlockDriver *old_backing_drv, *new_backing_drv;
char *filename;
const char *out_basefmt, *out_baseimg;
int c, flags, ret;
int unsafe = 0;
/* Parse commandline parameters */
out_baseimg = NULL;
out_basefmt = NULL;
for(;;) {
c = getopt(argc, argv, "uhF:b:");
if (c == -1)
break;
switch(c) {
case 'h':
help();
return 0;
case 'F':
out_basefmt = optarg;
break;
case 'b':
out_baseimg = optarg;
break;
case 'u':
unsafe = 1;
break;
}
}
if ((optind >= argc) || !out_baseimg)
help();
filename = argv[optind++];
/*
* Open the images.
*
* Ignore the old backing file for unsafe rebase in case we want to correct
* the reference to a renamed or moved backing file.
*/
bs = bdrv_new("");
if (!bs)
error("Not enough memory");
flags = BRDV_O_FLAGS | (unsafe ? BDRV_O_NO_BACKING : 0);
if (bdrv_open2(bs, filename, flags, NULL) < 0) {
error("Could not open '%s'", filename);
}
/* Find the right drivers for the backing files */
old_backing_drv = NULL;
new_backing_drv = NULL;
if (!unsafe && bs->backing_format[0] != '\0') {
old_backing_drv = bdrv_find_format(bs->backing_format);
if (old_backing_drv == NULL) {
error("Invalid format name: '%s'", bs->backing_format);
}
}
if (out_basefmt != NULL) {
new_backing_drv = bdrv_find_format(out_basefmt);
if (new_backing_drv == NULL) {
error("Invalid format name: '%s'", out_basefmt);
}
}
/* For safe rebasing we need to compare old and new backing file */
if (unsafe) {
/* Make the compiler happy */
bs_old_backing = NULL;
bs_new_backing = NULL;
} else {
char backing_name[1024];
bs_old_backing = bdrv_new("old_backing");
bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name));
if (bdrv_open2(bs_old_backing, backing_name, BRDV_O_FLAGS,
old_backing_drv))
{
error("Could not open old backing file '%s'", backing_name);
return -1;
}
bs_new_backing = bdrv_new("new_backing");
if (bdrv_open2(bs_new_backing, out_baseimg, BRDV_O_FLAGS,
new_backing_drv))
{
error("Could not open new backing file '%s'", backing_name);
return -1;
}
}
/*
* Check each unallocated cluster in the COW file. If it is unallocated,
* accesses go to the backing file. We must therefore compare this cluster
* in the old and new backing file, and if they differ we need to copy it
* from the old backing file into the COW file.
*
* If qemu-img crashes during this step, no harm is done. The content of
* the image is the same as the original one at any time.
*/
if (!unsafe) {
uint64_t num_sectors;
uint64_t sector;
int n, n1;
uint8_t buf_old[IO_BUF_SIZE];
uint8_t buf_new[IO_BUF_SIZE];
bdrv_get_geometry(bs, &num_sectors);
for (sector = 0; sector < num_sectors; sector += n) {
/* How many sectors can we handle with the next read? */
if (sector + (IO_BUF_SIZE / 512) <= num_sectors) {
n = (IO_BUF_SIZE / 512);
} else {
n = num_sectors - sector;
}
/* If the cluster is allocated, we don't need to take action */
if (bdrv_is_allocated(bs, sector, n, &n1)) {
n = n1;
continue;
}
/* Read old and new backing file */
if (bdrv_read(bs_old_backing, sector, buf_old, n) < 0) {
error("error while reading from old backing file");
}
if (bdrv_read(bs_new_backing, sector, buf_new, n) < 0) {
error("error while reading from new backing file");
}
/* If they differ, we need to write to the COW file */
uint64_t written = 0;
while (written < n) {
int pnum;
if (compare_sectors(buf_old + written * 512,
buf_new + written * 512, n, &pnum))
{
ret = bdrv_write(bs, sector + written,
buf_old + written * 512, pnum);
if (ret < 0) {
error("Error while writing to COW image: %s",
strerror(-ret));
}
}
written += pnum;
}
}
}
/*
* Change the backing file. All clusters that are different from the old
* backing file are overwritten in the COW file now, so the visible content
* doesn't change when we switch the backing file.
*/
ret = bdrv_change_backing_file(bs, out_baseimg, out_basefmt);
if (ret == -ENOSPC) {
error("Could not change the backing file to '%s': No space left in "
"the file header", out_baseimg);
} else if (ret < 0) {
error("Could not change the backing file to '%s': %s",
out_baseimg, strerror(-ret));
}
/*
* TODO At this point it is possible to check if any clusters that are
* allocated in the COW file are the same in the backing file. If so, they
* could be dropped from the COW file. Don't do this before switching the
* backing file, in case of a crash this would lead to corruption.
*/
/* Cleanup */
if (!unsafe) {
bdrv_delete(bs_old_backing);
bdrv_delete(bs_new_backing);
}
bdrv_delete(bs);
return 0;
}
static const img_cmd_t img_cmds[] = {
#define DEF(option, callback, arg_string) \
{ option, callback },
#include "qemu-img-cmds.h"
#undef DEF
#undef GEN_DOCS
{ NULL, NULL, },
};
int main(int argc, char **argv)
{
const img_cmd_t *cmd;
const char *cmdname;
bdrv_init();
if (argc < 2)
help();
cmdname = argv[1];
argc--; argv++;
/* find the command */
for(cmd = img_cmds; cmd->name != NULL; cmd++) {
if (!strcmp(cmdname, cmd->name)) {
return cmd->handler(argc, argv);
}
}
/* not found */
help();
return 0;
}
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