1guestfs-perl(3) Virtualization Support guestfs-perl(3)
2
6 guestfs-perl - How to use libguestfs from Perl
7
9 use Sys::Guestfs;
10 my $g = Sys::Guestfs->new ();
12 $g->add_drive_opts ('guest.img', format => 'raw');
13 $g->launch ();
14 $g->mount ('/dev/sda1', '/');
15 $g->touch ('/hello');
16 $g->shutdown ();
17 $g->close ();
18
20 This manual page documents how to call libguestfs from the Perl
21 programming language. This page just documents the differences from
22 the C API and gives some examples. If you are not familiar with using
23 libguestfs, you also need to read guestfs(3). To read the full Perl
24 API, see Sys::Guestfs(3).
25 ERRORS
27 Errors from libguestfs functions turn into calls to "croak" (see
28 Carp(3)).
29
31 #!/usr/bin/perl -w
32 # Example showing how to create a disk image.
34 use strict;
36 use Sys::Guestfs;
37 my $output = "disk.img";
39 my $g = new Sys::Guestfs ();
41 # Create a raw-format sparse disk image, 512 MB in size.
43 open FILE, ">$output" or die "$output: $!";
44 truncate FILE, 512 * 1024 * 1024 or die "$output: truncate: $!";
45 close FILE or die "$output: $!";
46 # Set the trace flag so that we can see each libguestfs call.
48 $g->set_trace (1);
49 # Attach the disk image to libguestfs.
51 $g->add_drive_opts ($output, format => "raw", readonly => 0);
52 # Run the libguestfs back-end.
54 $g->launch ();
55 # Get the list of devices. Because we only added one drive
57 # above, we expect that this list should contain a single
58 # element.
59 my @devices = $g->list_devices ();
60 if (@devices != 1) {
61 die "error: expected a single device from list-devices";
62 }
63 # Partition the disk as one single MBR partition.
65 $g->part_disk ($devices[0], "mbr");
66 # Get the list of partitions. We expect a single element, which
68 # is the partition we have just created.
69 my @partitions = $g->list_partitions ();
70 if (@partitions != 1) {
71 die "error: expected a single partition from list-partitions";
72 }
73 # Create a filesystem on the partition.
75 $g->mkfs ("ext4", $partitions[0]);
76 # Now mount the filesystem so that we can add files.
78 $g->mount ($partitions[0], "/");
79 # Create some files and directories.
81 $g->touch ("/empty");
82 my $message = "Hello, world\n";
83 $g->write ("/hello", $message);
84 $g->mkdir ("/foo");
85 # This one uploads the local file /etc/resolv.conf into
87 # the disk image.
88 $g->upload ("/etc/resolv.conf", "/foo/resolv.conf");
89 # Because we wrote to the disk and we want to detect write
91 # errors, call $g->shutdown. You don't need to do this:
92 # $g->close will do it implicitly.
93 $g->shutdown ();
94 # Note also that handles are automatically closed if they are
96 # reaped by reference counting. You only need to call close
97 # if you want to close the handle right away.
98 $g->close ();
99
101 #!/usr/bin/perl -w
102 # Example showing how to inspect a virtual machine disk.
104 use strict;
106 use Sys::Guestfs;
107 if (@ARGV < 1) {
109 die "usage: inspect_vm disk.img"
110 }
111 my $disk = $ARGV[0];
113 my $g = new Sys::Guestfs ();
115 # Attach the disk image read-only to libguestfs.
117 # You could also add an optional format => ... argument here. This is
118 # advisable since automatic format detection is insecure.
119 $g->add_drive_opts ($disk, readonly => 1);
120 # Run the libguestfs back-end.
122 $g->launch ();
123 # Ask libguestfs to inspect for operating systems.
125 my @roots = $g->inspect_os ();
126 if (@roots == 0) {
127 die "inspect_vm: no operating systems found";
128 }
129 for my $root (@roots) {
131 printf "Root device: %s\n", $root;
132 # Print basic information about the operating system.
134 printf " Product name: %s\n", $g->inspect_get_product_name ($root);
135 printf " Version: %d.%d\n",
136 $g->inspect_get_major_version ($root),
137 $g->inspect_get_minor_version ($root);
138 printf " Type: %s\n", $g->inspect_get_type ($root);
139 printf " Distro: %s\n", $g->inspect_get_distro ($root);
140 # Mount up the disks, like guestfish -i.
142 #
143 # Sort keys by length, shortest first, so that we end up
144 # mounting the filesystems in the correct order.
145 my %mps = $g->inspect_get_mountpoints ($root);
146 my @mps = sort { length $a <=> length $b } (keys %mps);
147 for my $mp (@mps) {
148 eval { $g->mount_ro ($mps{$mp}, $mp) };
149 if ($@) {
150 print "$@ (ignored)\n"
151 }
152 }
153 # If /etc/issue.net file exists, print up to 3 lines.
155 my $filename = "/etc/issue.net";
156 if ($g->is_file ($filename)) {
157 printf "--- %s ---\n", $filename;
158 my @lines = $g->head_n (3, $filename);
159 print "$_\n" foreach @lines;
160 }
161 # Unmount everything.
163 $g->umount_all ()
164 }
165
167 Sys::Guestfs(3), guestfs(3), guestfs-examples(3), guestfs-erlang(3),
168 guestfs-java(3), guestfs-lua(3), guestfs-ocaml(3), guestfs-python(3),
169 guestfs-recipes(1), guestfs-ruby(3), http://libguestfs.org/.
170
172 Richard W.M. Jones ("rjones at redhat dot com")
173
175 Copyright (C) 2011-2012 Red Hat Inc.
176
178 This manual page contains examples which we hope you will use in your
179 programs. The examples may be freely copied, modified and distributed
180 for any purpose without any restrictions.
181
183 To get a list of bugs against libguestfs, use this link:
184 https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools
185 To report a new bug against libguestfs, use this link:
187 https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
188 When reporting a bug, please supply:
190 · The version of libguestfs.
192 · Where you got libguestfs (eg. which Linux distro, compiled from
194 source, etc)
195 · Describe the bug accurately and give a way to reproduce it.
197 · Run libguestfs-test-tool(1) and paste the complete, unedited output
199 into the bug report.
200libguestfs-1.20.11 2013-08-27 guestfs-perl(3)