From: Richard Jones Date: Wed, 7 Apr 2010 19:30:46 +0000 (+0100) Subject: New tool: virt-make-fs for creating filesystems on devices. X-Git-Tag: 1.3.1~1 X-Git-Url: http://git.annexia.org/?a=commitdiff_plain;h=d868221d9f746ab17b83e7220cef9227fcad3696;p=libguestfs.git New tool: virt-make-fs for creating filesystems on devices. --- diff --git a/.gitignore b/.gitignore index dada5ad..fa23150 100644 --- a/.gitignore +++ b/.gitignore @@ -93,6 +93,7 @@ html/virt-inspector.1.html html/virt-list-filesystems.1.html html/virt-list-partitions.1.html html/virt-ls.1.html +html/virt-make-fs.1.html html/virt-rescue.1.html html/virt-resize.1.html html/virt-tar.1.html diff --git a/Makefile.am b/Makefile.am index 3ed7815..44fc893 100644 --- a/Makefile.am +++ b/Makefile.am @@ -131,6 +131,7 @@ HTMLFILES = \ html/virt-list-filesystems.1.html \ html/virt-list-partitions.1.html \ html/virt-ls.1.html \ + html/virt-make-fs.1.html \ html/virt-rescue.1.html \ html/virt-resize.1.html \ html/virt-tar.1.html \ @@ -169,6 +170,7 @@ all-local: -name 'virt-list-filesystems' -o \ -name 'virt-list-partitions' -o \ -name 'virt-ls' -o \ + -name 'virt-make-fs' -o \ -name 'virt-rescue' -o \ -name 'virt-resize' -o \ -name 'virt-tar' -o \ diff --git a/po/POTFILES.in b/po/POTFILES.in index 92106b6..a5a27fa 100644 --- a/po/POTFILES.in +++ b/po/POTFILES.in @@ -104,6 +104,7 @@ tools/virt-edit tools/virt-list-filesystems tools/virt-list-partitions tools/virt-ls +tools/virt-make-fs tools/virt-rescue tools/virt-resize tools/virt-tar diff --git a/tools/Makefile.am b/tools/Makefile.am index 1d7c0d1..9cc6139 100644 --- a/tools/Makefile.am +++ b/tools/Makefile.am @@ -24,6 +24,7 @@ tools = \ list-filesystems \ list-partitions \ ls \ + make-fs \ rescue \ resize \ tar \ @@ -84,6 +85,7 @@ TESTS = test-virt-cat.sh \ test-virt-df.sh \ test-virt-list-filesystems.sh \ test-virt-ls.sh \ + test-virt-make-fs.sh \ test-virt-tar.sh endif diff --git a/tools/test-virt-make-fs.sh b/tools/test-virt-make-fs.sh new file mode 100755 index 0000000..e246506 --- /dev/null +++ b/tools/test-virt-make-fs.sh @@ -0,0 +1,50 @@ +#!/bin/bash - + +export LANG=C +set -e + +# Engage in some montecarlo testing of virt-make-fs. +case $((RANDOM % 4)) in + 0) type="--type=ext2" ;; + 1) type="--type=ext3" ;; + 2) type="--type=ext4" ;; + 3) type="--type=ntfs" ;; + # Can't test vfat because we cannot create a tar archive + # where files are owned by UID:GID 0:0. As a result, tar + # in the appliance fails when trying to change the UID of + # the files to some non-zero value (not supported by FAT). + # 4) type="--type=vfat" ;; +esac + +case $((RANDOM % 2)) in + 0) format="--format=raw" ;; + 1) format="--format=qcow2" ;; +esac + +case $((RANDOM % 3)) in + 0) partition="--partition" ;; + 1) partition="--partition=gpt" ;; + 2) ;; +esac + +case $((RANDOM % 2)) in + 0) ;; + 1) size="--size=+1M" ;; +esac + +if [ -n "$LIBGUESTFS_DEBUG" ]; then debug=--debug; fi + +params="$type $format $partition $size $debug" +echo "test-virt-make-fs: parameters: $params" + +rm -f test.file test.tar output.img + +tarsize=$((RANDOM & 8191)) +echo "test-virt-make-fs: size of test file: $tarsize KB" +dd if=/dev/zero of=test.file bs=1024 count=$tarsize +tar -c -f test.tar test.file +rm test.file + +./virt-make-fs $params -- test.tar output.img + +rm test.tar output.img diff --git a/tools/virt-make-fs b/tools/virt-make-fs new file mode 100755 index 0000000..54c5a1d --- /dev/null +++ b/tools/virt-make-fs @@ -0,0 +1,571 @@ +#!/usr/bin/perl -w +# virt-make-fs +# Copyright (C) 2010 Red Hat Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + +use warnings; +use strict; + +use Sys::Guestfs; + +use Pod::Usage; +use Getopt::Long; +use File::Temp qw(tempdir); +use POSIX qw(mkfifo floor); +use Data::Dumper; +use String::ShellQuote qw(shell_quote); +use Locale::TextDomain 'libguestfs'; + +=encoding utf8 + +=head1 NAME + +virt-make-fs - Make a filesystem from a tar archive or files + +=head1 SYNOPSIS + + virt-make-fs [--options] input.tar output.img + + virt-make-fs [--options] input.tar.gz output.img + + virt-make-fs [--options] directory output.img + +=head1 DESCRIPTION + +Virt-make-fs is a command line tool for creating a filesystem from a +tar archive or some files in a directory. It is similar to tools like +L, L and L. Unlike those +tools, it can create common filesystem types like ext2/3 or NTFS, +which can be useful if you want to attach these filesystems to +existing virtual machines (eg. to import large amounts of read-only +data to a VM). + +Basic usage is: + + virt-make-fs input output + +where C is either a directory containing files that you want to +add, or a tar archive (either uncompressed tar or gzip-compressed +tar); and C is a disk image. The input type is detected +automatically. The output disk image defaults to a raw ext2 image +unless you specify extra flags (see L below). + +=head2 EXTRA SPACE + +Unlike formats such as tar and squashfs, a filesystem does not "just +fit" the files that it contains, but might have extra space. +Depending on how you are going to use the output, you might think this +extra space is wasted and want to minimize it, or you might want to +leave space so that more files can be added later. Virt-make-fs +defaults to minimizing the extra space, but you can use the C<--size> +flag to leave space in the filesystem if you want it. + +An alternative way to leave extra space but not make the output image +any bigger is to use an alternative disk image format (instead of the +default "raw" format). Using C<--format=qcow2> will use the native +QEmu/KVM qcow2 image format (check your hypervisor supports this +before using it). This allows you to choose a large C<--size> but the +extra space won't actually be allocated in the image until you try to +store something in it. + +Don't forget that you can also use local commands including +L and L to resize existing filesystems, +or rerun virt-make-resize to build another image from scratch. + +=head3 EXAMPLE + + virt-make-fs --format=qcow2 --size=+200M input output.img + +=head2 FILESYSTEM TYPE + +The default filesystem type is C. Just about any filesystem +type that libguestfs supports can be used (but I read-only +formats like ISO9660). Here are some of the more common choices: + +=over 4 + +=item I + +Note that ext3 filesystems contain a journal, typically 1-32 MB in size. +If you are not going to use the filesystem in a way that requires the +journal, then this is just wasted overhead. + +=item I or I + +Useful if exporting data to a Windows guest. + +I: The tar archive or local directory must only contain +files which are owned by root (ie. UID:GID = 0:0). The reason is that +the tar program running within libguestfs is unable to change the +ownership of non-root files, since vfat itself does not support this. + +=item I + +Lower overhead than C, but certain limitations on filename +length and total filesystem size. + +=back + +=head3 EXAMPLE + + virt-make-fs --type=minix input minixfs.img + +=head2 TO PARTITION OR NOT TO PARTITION + +Optionally virt-make-fs can add a partition table to the output disk. + +Adding a partition can make the disk image more compatible with +certain virtualized operating systems which don't expect to see a +filesystem directly located on a block device (Linux doesn't care and +will happily handle both types). + +On the other hand, if you have a partition table then the output image +is no longer a straight filesystem. For example you cannot run +L directly on a partitioned disk image. (However libguestfs +tools such as L and L can still be +used). + +=head3 EXAMPLE + +Add an MBR partition: + + virt-make-fs --partition -- input disk.img + +If the output disk image could be terabyte-sized or larger, it's +better to use an EFI/GPT-compatible partition table: + + virt-make-fs --partition=gpt --size=+4T --format=qcow2 input disk.img + +=head1 OPTIONS + +=over 4 + +=cut + +my $help; + +=item B<--help> + +Display brief help. + +=cut + +my $version; + +=item B<--version> + +Display version number and exit. + +=cut + +my $debug; + +=item B<--debug> + +Enable debugging information. + +=cut + +my $size; + +=item B<--size=ENE> + +=item B<--size=+ENE> + +=item B<-s ENE> + +=item B<-s +ENE> + +Use the C<--size> (or C<-s>) option to choose the size of the output +image. + +If this option is I given, then the output image will be just +large enough to contain all the files, with not much wasted space. + +To choose a fixed size output disk, specify an absolute number +followed by b/K/M/G/T/P/E to mean bytes, Kilobytes, Megabytes, +Gigabytes, Terabytes, Petabytes or Exabytes. This must be large +enough to contain all the input files, else you will get an error. + +To leave extra space, specify C<+> (plus sign) and a number followed +by b/K/M/G/T/P/E to mean bytes, Kilobytes, Megabytes, Gigabytes, +Terabytes, Petabytes or Exabytes. For example: C<--size=+200M> means +enough space for the input files, and (approximately) an extra 200 MB +free space. + +Note that virt-make-fs estimates free space, and therefore will not +produce filesystems containing precisely the free space requested. +(It is much more expensive and time-consuming to produce a filesystem +which has precisely the desired free space). + +=cut + +my $format = "raw"; + +=item B<--format=EfmtE> + +=item B<-F EfmtE> + +Choose the output disk image format. + +The default is C (raw disk image). + +For other choices, see the L manpage. The only other +choice that would really make sense here is C. + +=cut + +my $type = "ext2"; + +=item B<--type=EfsE> + +=item B<-t EfsE> + +Choose the output filesystem type. + +The default is C. + +Any filesystem which is supported read-write by libguestfs can be used +here. + +=cut + +my $partition; + +=item B<--partition> + +=item B<--partition=EparttypeE> + +If specified, this flag adds an MBR partition table to the output disk +image. + +You can change the partition table type, eg. C<--partition=gpt> for +large disks. + +Note that if you just use a lonesome C<--partition>, the Perl option +parser might consider the next parameter to be the partition type. +For example: + + virt-make-fs --partition input.tar ... + +would cause virt-make-fs to think you wanted to use a partition type +of C which is completely wrong. To avoid this, use C<--> +(a double dash) between options and the input file argument: + + virt-make-fs --partition -- input.tar ... + +=back + +=cut + +GetOptions ("help|?" => \$help, + "version" => \$version, + "debug" => \$debug, + "s|size=s" => \$size, + "F|format=s" => \$format, + "t|type=s" => \$type, + "partition:s" => \$partition, + ) or pod2usage (2); +pod2usage (1) if $help; +if ($version) { + my $g = Sys::Guestfs->new (); + my %h = $g->version (); + print "$h{major}.$h{minor}.$h{release}$h{extra}\n"; + exit +} + +die __"virt-make-fs input output\n" if @ARGV != 2; + +my $input = $ARGV[0]; +my $output = $ARGV[1]; + +# Input. What is it? Estimate how much space it will need. +# +# Estimation is a Hard Problem. Some factors which make it hard: +# +# - Superblocks, block free bitmaps, FAT and other fixed overhead +# - Indirect blocks (ext2, ext3), and extents +# - Journal size +# - Internal fragmentation of files +# +# What we could also do is try shrinking the filesystem after creating +# and populating it, but that is complex given partitions. + +my $estimate; # Estimated size required (in bytes). +my $ifmt; # Input format. + +if (-d $input) { + $ifmt = "directory"; + + my @cmd = ("du", "--apparent-size", "-b", "-s", $input); + open PIPE, "-|", @cmd or die "du $input: $!"; + + $_ = ; + if (/^(\d+)/) { + $estimate = $1; + } else { + die __"unexpected output from 'du' command"; + } +} else { + local $ENV{LANG} = "C"; + my @cmd = ("file", "-bsLz", $input); + open PIPE, "-|", @cmd or die "file $input: $!"; + + $ifmt = ; + chomp $ifmt; + close PIPE; + + if ($ifmt !~ /tar archive/) { + die __x("{f}: unknown input format: {fmt}\n", + f => $input, fmt => $ifmt); + } + + if ($ifmt =~ /compress.d/) { + if ($ifmt =~ /compress'd/) { + @cmd = ("uncompress", "-c", $input); + } elsif ($ifmt =~ /gzip compressed/) { + @cmd = ("gzip", "-cd", $input); + } elsif ($ifmt =~ /bzip2 compressed/) { + @cmd = ("bzip2", "-cd", $input); + } elsif ($ifmt =~ /xz compressed/) { + @cmd = ("xz", "-cd", $input); + } else { + die __x("{f}: unknown input format: {fmt}\n", + f => $input, fmt => $ifmt); + } + + open PIPE, "-|", @cmd or die "uncompress $input: $!"; + $estimate = 0; + $estimate += length while ; + close PIPE or die "close: $!"; + } else { + # Plain tar file, just get the size directly. Tar files have + # a 512 byte block size (compared with typically 1K or 4K for + # filesystems) so this isn't very accurate. + $estimate = -s $input; + } +} + +if ($debug) { + printf STDERR "input format = %s\n", $ifmt; + printf STDERR "estimate = %s bytes (%s 1K blocks, %s 4K blocks)\n", + $estimate, $estimate / 1024, $estimate / 4096; +} + +$estimate += 256 * 1024; # For superblocks &c. + +if ($type =~ /^ext[3-9]/) { + $estimate += 1024 * 1024; # For ext3/4, add some more for the journal. +} + +if ($type =~ /^ntfs/) { + $estimate += 4 * 1024 * 1024; # NTFS journal. +} + +$estimate *= 1.10; # Add 10%, see above. + +# Calculate the output size. + +if (!defined $size) { + $size = $estimate; +} else { + if ($size =~ /^\+([.\d]+)([bKMGTPE])$/) { + $size = $estimate + sizebytes ($1, $2); + } elsif ($size =~ /^([.\d]+)([bKMGTPE])$/) { + $size = sizebytes ($1, $2); + } else { + die __x("virt-make-fs: cannot parse size parameter: {sz}\n", + sz => $size); + } +} + +# Create the output disk. +# Take the unusual step of invoking qemu-img here. + +my @cmd = ("qemu-img", "create", "-f", $format, $output, $size); +system (@cmd) == 0 or + die __"qemu-img create: failed to create disk image, see earlier error messages\n"; + +eval { + print STDERR "starting libguestfs ...\n" if $debug; + + # Run libguestfs. + my $g = Sys::Guestfs->new (); + $g->add_drive ($output); + $g->launch (); + + if ($type eq "ntfs") { + $g->available ([ "ntfs3g" ]); + } + + # Partition the disk. + my $dev = "/dev/sda"; + if (defined $partition) { + $partition = "mbr" if $partition eq ""; + $g->part_disk ($dev, $partition); + $dev = "/dev/sda1"; + } + + print STDERR "creating $type filesystem on $dev ...\n" if $debug; + + # Create the filesystem. + $g->mkfs ($type, $dev); + $g->mount_options ("", $dev, "/"); + + # Copy the data in. + my $ifile; + + if ($ifmt eq "directory") { + my $pfile = create_pipe (); + my $cmd = sprintf ("tar -C %s -cf - . > $pfile &", + shell_quote ($input)); + print STDERR "command: $cmd\n" if $debug; + system ($cmd) == 0 or die __"tar: failed, see earlier messages\n"; + $ifile = $pfile; + } else { + if ($ifmt =~ /compress.d/) { + my $pfile = create_pipe (); + my $cmd; + if ($ifmt =~ /compress'd/) { + $cmd = sprintf ("uncompress -c %s > $pfile", + shell_quote ($input)); + } elsif ($ifmt =~ /gzip compressed/) { + $cmd = sprintf ("gzip -cd %s", shell_quote ($input)); + } elsif ($ifmt =~ /bzip2 compressed/) { + $cmd = sprintf ("bzip2 -cd %s", shell_quote ($input)); + } elsif ($ifmt =~ /xz compressed/) { + $cmd = sprintf ("xz -cd %s", shell_quote ($input)); + } else { + die __x("{f}: unknown input format: {fmt}\n", + f => $input, fmt => $ifmt); + } + $cmd .= " > $pfile &"; + print STDERR "command: $cmd\n" if $debug; + system ($cmd) == 0 or + die __"uncompress command failed, see earlier messages\n"; + $ifile = $pfile; + } else { + print STDERR "reading directly from $input\n" if $debug; + $ifile = $input; + } + } + + if ($debug) { + # For debugging, print statvfs before and after doing + # the tar-in. + my %stat = $g->statvfs ("/"); + print STDERR "Before uploading ...\n"; + print STDERR Dumper(\%stat); + } + + print STDERR "Uploading from $ifile to / ...\n" if $debug; + $g->tar_in ($ifile, "/"); + + if ($debug) { + my %stat = $g->statvfs ("/"); + print STDERR "After uploading ...\n"; + print STDERR Dumper(\%stat); + } + + print STDERR "finishing off\n" if $debug; + $g->umount_all (); + $g->sync (); + undef $g; +}; +if ($@) { + # Error: delete the output before exiting. + my $err = $@; + unlink $output; + if ($err =~ /tar_in/) { + print STDERR __"virt-make-fs: error copying contents into filesystem\nAn error here usually means that the program did not estimate the\nfilesystem size correctly. Please read the BUGS section of the manpage.\n"; + } + print STDERR $err; + exit 1; +} + +exit 0; + +sub sizebytes +{ + local $_ = shift; + my $unit = shift; + + $_ *= 1024 if $unit =~ /[KMGTPE]/; + $_ *= 1024 if $unit =~ /[MGTPE]/; + $_ *= 1024 if $unit =~ /[GTPE]/; + $_ *= 1024 if $unit =~ /[TPE]/; + $_ *= 1024 if $unit =~ /[PE]/; + $_ *= 1024 if $unit =~ /[E]/; + + return floor($_); +} + +sub create_pipe +{ + local $_; + my $dir = tempdir (CLEANUP => 1); + my $pipe = "$dir/pipe"; + mkfifo ($pipe, 0600) or + die "mkfifo: $pipe: $!"; + return $pipe; +} + +=head1 SEE ALSO + +L, +L, +L, +L, +L, +L, +L, +L, +L, +L, +L. + +=head1 BUGS + +When reporting bugs, please enable debugging and capture the +I output: + + export LIBGUESTFS_DEBUG=1 + virt-make-fs --debug [...] > /tmp/virt-make-fs.log 2>&1 + +Attach /tmp/virt-make-fs.log to a new bug report at +L + +=head1 AUTHOR + +Richard W.M. Jones L + +=head1 COPYRIGHT + +Copyright (C) 2010 Red Hat Inc. + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2 of the License, or +(at your option) any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program; if not, write to the Free Software +Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.