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e2fsprogs
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e2image: add offset switches 

Add -o and -O switches to specify the offset where the source
and destination filesystems start.  This is useful if you have
an image of a partitioned disk or wish to create one.

Signed-off-by: Phillip Susi <psusi@ubuntu.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
debian-1.42.9
Phillip Susi 2013-12-16 11:32:39 -05:00 committed by Theodore Ts'o
parent b3c2a63813
commit 6b5535f409
2 changed files with 60 additions and 6 deletions
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36
misc/e2image.8.in
View File

@ -10,6 +10,14 @@ e2image \- Save critical ext2/ext3/ext4 filesystem metadata to a file
[
.B \-rsIQa
]
[
.B \-o
.I source_offset
]
[
.B \-O
.I dest_offset
]
.I device
.I image-file
.SH DESCRIPTION
@ -201,6 +209,34 @@ give an image that is suitable to use to clone the entire FS or
for backup purposes. Note that this option only works with the
raw or QCOW2 formats.
.PP
.SH OFFSETS
Normally a filesystem starts at the beginning of a partition, and
.B e2image
is run on the partition. When working with image files, you don't
have the option of using the partition device, so you can specify
the offset where the filesystem starts directly with the
.B \-o
option. Similarly the
.B \-O
option specifies the offset that should be seeked to in the destination
before writing the filesystem.
.PP
For example, if you have a
.B dd
image of a whole hard drive that contains an ext2 fs in a partition
starting at 1 MiB, you can clone that fs with:
.PP
.br
\ \fBe2image \-aro 1048576 img /dev/sda1\fR
.br
.PP
Or you can clone a fs into an image file, leaving room in the first
MiB for a partition table with:
.PP
.br
\ \fBe2image -arO 1048576 /dev/sda1 img\fR
.br
.PP
.SH AUTHOR
.B e2image
was written by Theodore Ts'o (tytso@mit.edu).

30
misc/e2image.c
View File

@ -55,6 +55,7 @@ static char * device_name = NULL;
static char all_data;
static char output_is_blk;
/* writing to blk device: don't skip zeroed blocks */
blk64_t source_offset, dest_offset;
static void lseek_error_and_exit(int errnum)
{
@ -87,7 +88,7 @@ static int get_bits_from_size(size_t size)
static void usage(void)
{
fprintf(stderr, _("Usage: %s [-rsIQaf] device image_file\n"),
fprintf(stderr, _("Usage: %s [-rsIQaf] [-o source_offset] [-O dest_offset] device image_file\n"),
program_name);
exit (1);
}
@ -1278,7 +1279,7 @@ int main (int argc, char ** argv)
if (argc && *argv)
program_name = *argv;
add_error_table(&et_ext2_error_table);
while ((c = getopt(argc, argv, "rsIQaf")) != EOF)
while ((c = getopt(argc, argv, "rsIQafo:O:")) != EOF)
switch (c) {
case 'I':
flags |= E2IMAGE_INSTALL_FLAG;
@ -1302,6 +1303,12 @@ int main (int argc, char ** argv)
case 'f':
ignore_rw_mount = 1;
break;
case 'o':
source_offset = strtoull(optarg, NULL, 0);
break;
case 'O':
dest_offset = strtoull(optarg, NULL, 0);
break;
default:
usage();
}
@ -1313,7 +1320,11 @@ int main (int argc, char ** argv)
"with raw or QCOW2 images.");
exit(1);
}
if ((source_offset || dest_offset) && img_type != E2IMAGE_RAW) {
com_err(program_name, 0,
"Offsets are only allowed with raw images.");
exit(1);
}
device_name = argv[optind];
image_fn = argv[optind+1];
@ -1346,9 +1357,11 @@ int main (int argc, char ** argv)
goto skip_device;
}
}
retval = ext2fs_open (device_name, open_flag, 0, 0,
unix_io_manager, &fs);
char *options;
asprintf (&options, "offset=%llu", source_offset);
retval = ext2fs_open2 (device_name, options, open_flag, 0, 0,
unix_io_manager, &fs);
free (options);
if (retval) {
com_err (program_name, retval, _("while trying to open %s"),
device_name);
@ -1367,6 +1380,11 @@ skip_device:
exit(1);
}
}
if (dest_offset)
if (ext2fs_llseek (fd, dest_offset, SEEK_SET) < 0) {
perror("ext2fs_llseek");
exit(1);
}
if ((img_type & E2IMAGE_QCOW2) && (fd == 1)) {
com_err(program_name, 0, "QCOW2 image can not be written to "