Matthew Booth
2009-Jul-31 16:40 UTC
[Libguestfs] [PATCH] Use grub entries to find Linux kernels
This change adds grub parsing to Lib.pm. It adds the following structure to $os:
{boot}
->{configs}
->[0]
->{title} = "Fedora (2.6.29.6-213.fc11.i686.PAE)"
->{kernel} = \kernel
->{cmdline} = "ro root=/dev/mapper/vg_mbooth-lv_root rhgb"
->{initrd} = \initrd
->{default} = 0
The kernel and initrd entries are just references to their top level entries
under kernels and initrd_modules respectively.
It also changes the way Linux kernels and initrd are discovered. Instead of
searching /lib/modules and /boot for files with matching names, kernels and
initrds are scanned as they are discovered in grub.conf.
---
perl/lib/Sys/Guestfs/Lib.pm | 278 +++++++++++++++++++++++++++++--------------
1 files changed, 189 insertions(+), 89 deletions(-)
diff --git a/perl/lib/Sys/Guestfs/Lib.pm b/perl/lib/Sys/Guestfs/Lib.pm
index bbc583f..20e29ff 100644
--- a/perl/lib/Sys/Guestfs/Lib.pm
+++ b/perl/lib/Sys/Guestfs/Lib.pm
@@ -1343,7 +1343,6 @@ sub inspect_in_detail
_check_for_kernels ($g, $os);
if ($os->{os} eq "linux") {
_find_modprobe_aliases ($g, $os);
- _check_for_initrd ($g, $os);
}
}
@@ -1392,48 +1391,170 @@ sub _check_for_applications
sub _check_for_kernels
{
- local $_;
- my $g = shift;
- my $os = shift;
+ my ($g, $os) = @_;
- my @kernels;
+ if ($os->{os} eq "linux") {
+ # Iterate over entries in grub.conf, populating $os->{boot}
+ # For every kernel we find, inspect it and add to $os->{kernels}
+
+ my @boot_configs;
+
+ # We want
+ # $os->{boot}
+ # ->{configs}
+ # ->[0]
+ # ->{title} = "Fedora
(2.6.29.6-213.fc11.i686.PAE)"
+ # ->{kernel} = \kernel
+ # ->{cmdline} = "ro
root=/dev/mapper/vg_mbooth-lv_root rhgb"
+ # ->{initrd} = \initrd
+ # ->{default} = \config
+ # Initialise augeas
+ $g->aug_init("/", 16);
+
+ my @configs = ();
+ # Get all configurations from grub
+ foreach my $bootable
+ ($g->aug_match("/files/etc/grub.conf/title"))
+ {
+ my %config = ();
+ $config{title} = $g->aug_get($bootable);
+
+ my $grub_kernel;
+ eval {
+ $grub_kernel = $g->aug_get("$bootable/kernel");
+ };
+ if($@) {
+ warn __x("Grub entry {title} has no kernel",
+ title => $config{title});
+ }
- my $osn = $os->{os};
- if ($osn eq "linux") {
- # Installed kernels will have a corresponding /lib/modules/<version>
- # directory, which is the easiest way to find out what kernels
- # are installed, and what modules are available.
- foreach ($g->ls ("/lib/modules")) {
- if ($g->is_dir ("/lib/modules/$_")) {
- my %kernel;
- $kernel{version} = $_;
-
- # List modules.
- my @modules;
- my $any_module;
- my $prefix = "/lib/modules/$_";
- foreach ($g->find ($prefix)) {
- if (m,/([^/]+)\.ko$, || m,([^/]+)\.o$,) {
- $any_module = "$prefix$_" unless defined $any_module;
- push @modules, $1;
- }
- }
+ # Check we've got a kernel entry
+ if(defined($grub_kernel)) {
+ # Parse a kernel path and optional kernel command line
+ if($grub_kernel =~ /^\s*(\S+)(?:\s+(.*))?$/) {
+ my $kernel_path = $1;
+ $config{cmdline} = $2 if defined($2);
+
+ my $kernel = _inspect_linux_kernel($g, $os,
"/boot$1");
+
+ # Check the kernel was recognised
+ if(defined($kernel)) {
+ $config{kernel} = $kernel;
+
+ # Look for an initrd entry
+ my $initrd;
+ eval {
+ $initrd =
$g->aug_get("$bootable/initrd");
+ };
+
+ unless($@) {
+ $config{initrd} +
_inspect_initrd($g, $os, "/boot$initrd",
+ $kernel->{version});
+ } else {
+ warn __x("Grub entry {title} does not specify
an ".
+ "initrd", title =>
$config{title});
+ }
+ }
+ }
+ else {
+ warn __x("Unexpected grub kernel line:
{grub_kernel}",
+ grub_kernel => $grub_kernel);
+ next;
+ }
+ }
- $kernel{modules} = \@modules;
+ push(@configs, \%config);
+ }
- # Determine kernel architecture by looking at the arch
- # of any kernel module.
- $kernel{arch} = file_architecture ($g, $any_module);
- push @kernels, \%kernel;
- }
- }
+ # Create the top level boot entry
+ my %boot;
+ $boot{configs} = \@configs;
- } elsif ($osn eq "windows") {
+ # Add the default configuration
+ eval {
+ $boot{default} =
$g->aug_get("/files/etc/grub.conf/default");
+ };
+ if($@) {
+ warn __"No grub default specified";
+ }
+
+ $os->{boot} = \%boot;
+ }
+
+ elsif ($os->{os} eq "windows") {
# XXX
}
+}
+
+sub _inspect_linux_kernel
+{
+ my ($g, $os, $path) = @_;
+
+ my %kernel = ();
+
+ $kernel{path} = $path;
+
+ # Try to get the kernel version by running file against it
+ my $version;
+ my $filedesc = $g->file($path);
+ if($filedesc =~ /^$path: Linux kernel .*\bversion\s+(\S+)\b/) {
+ $version = $1;
+ }
+
+ # Sometimes file can't work out the kernel version, for example because
it's
+ # a Xen PV kernel. In this case try to guess the version from the filename
+ else {
+ if($path =~ m{/boot/vmlinuz-(.*)}) {
+ $version = $1;
+
+ # Check /lib/modules/$version exists
+ if(!$g->is_dir("/lib/modules/$version")) {
+ warn __x("Didn't find modules directory {modules} for
kernel ".
+ "{path}", modules =>
"/lib/modules/$version",
+ path => $path);
+
+ # Give up
+ return undef;
+ }
+ } else {
+ warn __x("Couldn't guess kernel version number from path
for ".
+ "kernel {path}", path => $path);
+
+ # Give up
+ return undef;
+ }
+ }
+
+ $kernel{version} = $version;
+
+ # List modules.
+ my @modules;
+ my $any_module;
+ my $prefix = "/lib/modules/$version";
+ foreach my $module ($g->find ($prefix)) {
+ if ($module =~ m{/([^/]+)\.(?:ko|o)$}) {
+ $any_module = "$prefix$module" unless defined
$any_module;
+ push @modules, $1;
+ }
+ }
+
+ $kernel{modules} = \@modules;
+
+ # Determine kernel architecture by looking at the arch
+ # of any kernel module.
+ $kernel{arch} = file_architecture ($g, $any_module);
+
+ # Put this kernel on the top level kernel list
+ my $kernels = $os->{kernels};
+ if(!defined($kernels)) {
+ $kernels = [];
+ $os->{kernels} = $kernels;
+ }
+ push(@$kernels, \%kernel);
- $os->{kernels} = \@kernels;
+ return \%kernel;
}
# Find all modprobe aliases. Specifically, this looks in the following
@@ -1450,28 +1571,14 @@ sub _find_modprobe_aliases
my $os = shift;
# Initialise augeas
- my $success = 0;
- $success = $g->aug_init("/", 16);
-
- # Register /etc/modules.conf and /etc/conf.modules to the Modprobe lens
- my @results;
- @results = $g->aug_match("/augeas/load/Modprobe/incl");
-
- # Calculate the next index of /augeas/load/Modprobe/incl
- my $i = 1;
- foreach ( @results ) {
- next unless m{/augeas/load/Modprobe/incl\[(\d*)]};
- $i = $1 + 1 if ($1 == $i);
- }
+ $g->aug_init("/", 16);
- $success = $g->aug_set("/augeas/load/Modprobe/incl[$i]",
- "/etc/modules.conf");
- $i++;
- $success = $g->aug_set("/augeas/load/Modprobe/incl[$i]",
- "/etc/conf.modules");
+ # Register additional paths to the Modprobe lens
+ $g->aug_set("/augeas/load/Modprobe/incl[last()+1]",
"/etc/modules.conf");
+ $g->aug_set("/augeas/load/Modprobe/incl[last()+1]",
"/etc/conf.modules");
# Make augeas reload
- $success = $g->aug_load();
+ $g->aug_load();
my %modprobe_aliases;
@@ -1479,9 +1586,7 @@ sub _find_modprobe_aliases
/files/etc/modules.conf/alias
/files/etc/modprobe.conf/alias
/files/etc/modprobe.d/*/alias) {
- @results = $g->aug_match($pattern);
-
- for my $path ( @results ) {
+ for my $path ( $g->aug_match($pattern) ) {
$path =~ m{^/files(.*)/alias(?:\[\d*\])?$}
or die __x("{path} doesn't match augeas pattern",
path => $path);
@@ -1505,45 +1610,40 @@ sub _find_modprobe_aliases
$os->{modprobe_aliases} = \%modprobe_aliases;
}
-# Get a listing of device drivers in any initrd corresponding to a
-# kernel. This is an indication of what can possibly be booted.
-
-sub _check_for_initrd
+# Get a listing of device drivers from an initrd
+sub _inspect_initrd
{
- local $_;
- my $g = shift;
- my $os = shift;
+ my ($g, $os, $path, $version) = @_;
+
+ my @modules;
+
+ # Disregard old-style compressed ext2 files and only work with real
+ # compressed cpio files, since cpio takes ages to (fail to) process
anything
+ # else.
+ if ($g->file ($path) =~ /cpio/) {
+ eval {
+ @modules = $g->initrd_list ($path);
+ };
+ unless ($@) {
+ @modules = grep { m{([^/]+)\.(?:ko|o)$} } @modules;
+ } else {
+ warn __x("{filename}: could not read initrd format",
+ filename => "$path");
+ }
+ }
- my %initrd_modules;
-
- foreach my $initrd ($g->ls ("/boot")) {
- if ($initrd =~ m/^initrd-(.*)\.img$/ && $g->is_file
("/boot/$initrd")) {
- my $version = $1;
- my @modules;
-
- # Disregard old-style compressed ext2 files and only
- # work with real compressed cpio files, since cpio
- # takes ages to (fail to) process anything else.
- if ($g->file ("/boot/$initrd") =~ /cpio/) {
- eval {
- @modules = $g->initrd_list ("/boot/$initrd");
- };
- unless ($@) {
- @modules = grep { m,([^/]+)\.ko$, || m,([^/]+)\.o$, }
- @modules;
- $initrd_modules{$version} = \@modules
- } else {
- warn __x("{filename}: could not read initrd format",
- filename => "/boot/$initrd");
- }
- }
- }
+ # Add to the top level initrd_modules entry
+ my $initrd_modules = $os->{initrd_modules};
+ if(!defined($initrd_modules)) {
+ $initrd_modules = {};
+ $os->{initrd_modules} = $initrd_modules;
}
+
+ $initrd_modules->{$version} = \@modules;
- $os->{initrd_modules} = \%initrd_modules;
+ return \@modules;
}
-
1;
=head1 COPYRIGHT
--
1.6.2.5
Richard W.M. Jones
2009-Aug-02 15:33 UTC
[Libguestfs] [PATCH] Use grub entries to find Linux kernels
On Fri, Jul 31, 2009 at 05:40:23PM +0100, Matthew Booth wrote:> This change adds grub parsing to Lib.pm. It adds the following structure to $os: > {boot} > ->{configs} > ->[0] > ->{title} = "Fedora (2.6.29.6-213.fc11.i686.PAE)" > ->{kernel} = \kernel > ->{cmdline} = "ro root=/dev/mapper/vg_mbooth-lv_root rhgb" > ->{initrd} = \initrd > ->{default} = 0 > > The kernel and initrd entries are just references to their top level entries > under kernels and initrd_modules respectively. > > It also changes the way Linux kernels and initrd are discovered. Instead of > searching /lib/modules and /boot for files with matching names, kernels and > initrds are scanned as they are discovered in grub.conf.The patch looks good, but it can't go in because it is missing updates to the associated POD. Rich. -- Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into Xen guests. http://et.redhat.com/~rjones/virt-p2v