#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
/* 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"
+ const char *help_msg =
+ "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"
- " check [-f fmt] filename\n"
- " create [-F fmt] [-b base_image] [-f fmt] [-o options] filename [size]\n"
- " commit [-f fmt] filename\n"
- " convert [-c] [-f fmt] [-O output_fmt] [-o options] [-B output_base_image] filename [filename2 [...]] output_filename\n"
- " info [-f fmt] filename\n"
- " snapshot [-l | -a snapshot | -c snapshot | -d snapshot] filename\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"
- " 'base_image' is the read-only disk image which is used as base for a copy on\n"
- " write image; the copy on write image only stores the modified data\n"
- " 'output_base_image' forces the output image to be created as a copy on write\n"
- " image of the specified base image; 'output_base_image' should have the same\n"
- " content as the input's base image, however the path, image format, etc may\n"
- " differ\n"
" 'fmt' is the disk image format. It is guessed automatically in most cases\n"
- " 'size' is the disk image size in kilobytes. Optional suffixes\n"
- " 'M' (megabyte, 1024 * 1024) and 'G' (gigabyte, 1024 * 1024 * 1024) are\n"
- " supported any 'k' or 'K' is ignored\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"
" '-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:");
+ " '-l' lists all snapshots in the given image\n";
+
+ printf("%s\nSupported formats:", help_msg);
bdrv_iterate_format(format_print, NULL);
printf("\n");
exit(1);
#endif
static BlockDriverState *bdrv_new_open(const char *filename,
- const char *fmt)
+ const char *fmt,
+ int readonly)
{
BlockDriverState *bs;
BlockDriver *drv;
char password[256];
+ int flags = BRDV_O_FLAGS;
bs = bdrv_new("");
if (!bs)
} else {
drv = NULL;
}
- if (bdrv_open2(bs, filename, BRDV_O_FLAGS, drv) < 0) {
+ if (!readonly) {
+ flags |= BDRV_O_RDWR;
+ }
+ if (bdrv_open2(bs, filename, flags, drv) < 0) {
error("Could not open '%s'", filename);
}
if (bdrv_is_encrypted(bs)) {
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);
}
- } else {
- param = parse_option_parameters("", drv->create_options, param);
}
/* Get the filename */
// 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 == 0) {
+ if (get_option_parameter(param, BLOCK_OPT_SIZE)->value.n == -1) {
QEMUOptionParameter *backing_file =
get_option_parameter(param, BLOCK_OPT_BACKING_FILE);
}
}
- bs = bdrv_new_open(backing_file->value.s, fmt);
+ bs = bdrv_new_open(backing_file->value.s, fmt, 1);
bdrv_get_geometry(bs, &size);
size *= 512;
bdrv_delete(bs);
} else if (ret == -EFBIG) {
error("The image size is too large for file format '%s'", fmt);
} else {
- error("Error while formatting");
+ error("%s: error while creating %s: %s", filename, fmt, strerror(-ret));
}
}
return 0;
} else {
drv = NULL;
}
- if (bdrv_open2(bs, filename, BRDV_O_FLAGS, drv) < 0) {
+ if (bdrv_open2(bs, filename, BRDV_O_FLAGS | BDRV_O_RDWR, drv) < 0) {
error("Could not open '%s'", filename);
}
ret = bdrv_commit(bs);
return v;
}
-#define IO_BUF_SIZE 65536
+/*
+ * 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)
{
BlockDriverState **bs, *out_bs;
int64_t total_sectors, nb_sectors, sector_num, bs_offset;
uint64_t bs_sectors;
- uint8_t buf[IO_BUF_SIZE];
+ uint8_t * buf;
const uint8_t *buf1;
BlockDriverInfo bdi;
QEMUOptionParameter *param = NULL;
total_sectors = 0;
for (bs_i = 0; bs_i < bs_n; bs_i++) {
- bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt);
+ bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt, 1);
if (!bs[bs_i])
error("Could not open '%s'", argv[optind + bs_i]);
bdrv_get_geometry(bs[bs_i], &bs_sectors);
if (options && !strcmp(options, "?")) {
print_option_help(drv->create_options);
+ free(bs);
return 0;
}
} 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);
+ error("%s: error while converting %s: %s", out_filename, out_fmt, strerror(-ret));
}
}
- out_bs = bdrv_new_open(out_filename, out_fmt);
+ out_bs = bdrv_new_open(out_filename, out_fmt, 0);
bs_i = 0;
bs_offset = 0;
bdrv_get_geometry(bs[0], &bs_sectors);
+ buf = qemu_malloc(IO_BUF_SIZE);
if (flags & BLOCK_FLAG_COMPRESS) {
if (bdrv_get_info(out_bs, &bdi) < 0)
if (n > bs_offset + bs_sectors - sector_num)
n = bs_offset + bs_sectors - sector_num;
- if (strcmp(drv->format_name, "host_device")) {
- if (!bdrv_is_allocated(bs[bs_i], sector_num - bs_offset,
- n, &n1)) {
- sector_num += n1;
- continue;
+ 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;
}
- /* 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 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 (strcmp(drv->format_name, "host_device") == 0 || out_baseimg ||
+ 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");
}
}
}
+ qemu_free(buf);
bdrv_delete(out_bs);
for (bs_i = 0; bs_i < bs_n; bs_i++)
bdrv_delete(bs[bs_i]);
} else {
drv = NULL;
}
- if (bdrv_open2(bs, filename, BRDV_O_FLAGS, drv) < 0) {
+ 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));
#define SNAPSHOT_APPLY 3
#define SNAPSHOT_DELETE 4
-static void img_snapshot(int argc, char **argv)
+static int img_snapshot(int argc, char **argv)
{
BlockDriverState *bs;
QEMUSnapshotInfo sn;
char *filename, *snapshot_name = NULL;
- int c, ret;
+ int c, ret, bdrv_oflags;
int action = 0;
qemu_timeval tv;
+ bdrv_oflags = BDRV_O_RDWR;
/* Parse commandline parameters */
for(;;) {
c = getopt(argc, argv, "la:c:d:h");
switch(c) {
case 'h':
help();
- return;
+ return 0;
case 'l':
if (action) {
help();
- return;
+ return 0;
}
action = SNAPSHOT_LIST;
+ bdrv_oflags &= ~BDRV_O_RDWR; /* no need for RW */
break;
case 'a':
if (action) {
help();
- return;
+ return 0;
}
action = SNAPSHOT_APPLY;
snapshot_name = optarg;
case 'c':
if (action) {
help();
- return;
+ return 0;
}
action = SNAPSHOT_CREATE;
snapshot_name = optarg;
case 'd':
if (action) {
help();
- return;
+ return 0;
}
action = SNAPSHOT_DELETE;
snapshot_name = optarg;
if (!bs)
error("Not enough memory");
- if (bdrv_open2(bs, filename, 0, NULL) < 0) {
+ if (bdrv_open2(bs, filename, bdrv_oflags, NULL) < 0) {
error("Could not open '%s'", filename);
}
/* Cleanup */
bdrv_delete(bs);
+
+ return 0;
+}
+
+static int img_rebase(int argc, char **argv)
+{
+ BlockDriverState *bs, *bs_old_backing, *bs_new_backing;
+ BlockDriver *drv, *old_backing_drv, *new_backing_drv;
+ char *filename;
+ const char *fmt, *out_basefmt, *out_baseimg;
+ int c, flags, ret;
+ int unsafe = 0;
+
+ /* Parse commandline parameters */
+ fmt = NULL;
+ out_baseimg = NULL;
+ out_basefmt = NULL;
+
+ for(;;) {
+ c = getopt(argc, argv, "uhf:F:b:");
+ if (c == -1)
+ break;
+ switch(c) {
+ case 'h':
+ help();
+ return 0;
+ case 'f':
+ fmt = optarg;
+ break;
+ 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");
+
+ drv = NULL;
+ if (fmt) {
+ drv = bdrv_find_format(fmt);
+ if (drv == NULL) {
+ error("Invalid format name: '%s'", fmt);
+ }
+ }
+
+ flags = BRDV_O_FLAGS | BDRV_O_RDWR | (unsafe ? BDRV_O_NO_BACKING : 0);
+ if (bdrv_open2(bs, filename, flags, drv) < 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 | BDRV_O_RDWR,
+ new_backing_drv))
+ {
+ error("Could not open new backing file '%s'", out_baseimg);
+ 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;
+ uint8_t * buf_new;
+
+ buf_old = qemu_malloc(IO_BUF_SIZE);
+ buf_new = qemu_malloc(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 - written, &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;
+ }
+ }
+
+ qemu_free(buf_old);
+ qemu_free(buf_new);
+ }
+
+ /*
+ * 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 char *cmd;
+ const img_cmd_t *cmd;
+ const char *cmdname;
bdrv_init();
if (argc < 2)
help();
- cmd = argv[1];
+ cmdname = argv[1];
argc--; argv++;
- if (!strcmp(cmd, "create")) {
- img_create(argc, argv);
- } else if (!strcmp(cmd, "check")) {
- img_check(argc, argv);
- } else if (!strcmp(cmd, "commit")) {
- img_commit(argc, argv);
- } else if (!strcmp(cmd, "convert")) {
- img_convert(argc, argv);
- } else if (!strcmp(cmd, "info")) {
- img_info(argc, argv);
- } else if (!strcmp(cmd, "snapshot")) {
- img_snapshot(argc, argv);
- } else {
- help();
+
+ /* 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;
}
projects / qemu.git / blobdiff