Matthew Booth
2009-Aug-03 10:50 UTC
[Libguestfs] [REPOST] Use grub entries to find Linux kernels
This is a repost of the patch I sent on Friday. I know it was already ACK'd, but I've changed a fair bit in addition to adding the requested POD. Specifically: I discovered that augeas's grub lens wasn't returning cmdline the way I expected. This is fixed. The kernel package, if known, is output as a property of the kernel. The XML output of virt-inspector is updated with all the new output.
Matthew Booth
2009-Aug-03 10:50 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. Additionally, the following attributes are added to the kernels top level entry: * path The path to the kernel's vmlinuz file. * package The name of the package which installed the kernel. The xml output of virt-inspector is updated to reflect all of the above changes. --- inspector/virt-inspector.pl | 23 +++ perl/lib/Sys/Guestfs/Lib.pm | 341 ++++++++++++++++++++++++++++++++----------- 2 files changed, 275 insertions(+), 89 deletions(-) diff --git a/inspector/virt-inspector.pl b/inspector/virt-inspector.pl index d2acf06..17c6375 100755 --- a/inspector/virt-inspector.pl +++ b/inspector/virt-inspector.pl @@ -530,6 +530,27 @@ sub output_xml_os } $xml->endTag("applications"); + if(defined($os->{boot}) && defined($os->{boot}->{configs})) { + my $default = $os->{boot}->{default}; + my $configs = $os->{boot}->{configs}; + + $xml->startTag("boot"); + for(my $i = 0; $i < scalar(@$configs); $i++) { + my $config = $configs->[$i]; + + my @attrs = (); + push(@attrs, ("default" => 1)) if($default == $i); + $xml->startTag("config", @attrs); + $xml->dataElement("title", $config->{title}); + $xml->dataElement("kernel", $config->{kernel}->{version}) + if(defined($config->{kernel})); + $xml->dataElement("cmdline", $config->{cmdline}) + if(defined($config->{cmdline})); + $xml->endTag("config"); + } + $xml->endTag("boot"); + } + $xml->startTag("kernels"); my @kernels = @{$os->{kernels}}; foreach (@kernels) { @@ -542,6 +563,8 @@ sub output_xml_os $xml->dataElement("module", $_); } $xml->endTag("modules"); + $xml->dataElement("path", $_->{path}) if(defined($_->{path})); + $xml->dataElement("package", $_->{package}) if(defined($_->{package})); $xml->endTag("kernel"); } $xml->endTag("kernels"); diff --git a/perl/lib/Sys/Guestfs/Lib.pm b/perl/lib/Sys/Guestfs/Lib.pm index bbc583f..ba5aea6 100644 --- a/perl/lib/Sys/Guestfs/Lib.pm +++ b/perl/lib/Sys/Guestfs/Lib.pm @@ -1296,6 +1296,44 @@ finds. These extra keys are: List of applications. +=item boot + +Boot configurations. A hash containing: + +=over 4 + +=item configs + +An array of boot configurations. Each array entry is a hash containing: + +=over 4 + +=item initrd + +A reference to the expanded initrd structure (see below) for the initrd used by +this boot configuration. + +=item kernel + +A reference to the expanded kernel structure (see below) for the kernel used by +this boot configuration. + +=item title + +The human readable name of the configuration. + +=item cmdline + +The kernel command line. + +=back + +=item default + +The index of the default configuration in the configs array + +=back + =item kernels List of kernels. @@ -1316,6 +1354,14 @@ Kernel architecture (eg. C<x86-64>). List of modules. +=item path + +The path to the kernel's vmlinuz file. + +=item package + +If the kernel was installed in a package, the name of that package. + =back =item modprobe_aliases @@ -1343,7 +1389,6 @@ sub inspect_in_detail _check_for_kernels ($g, $os); if ($os->{os} eq "linux") { _find_modprobe_aliases ($g, $os); - _check_for_initrd ($g, $os); } } @@ -1392,48 +1437,187 @@ 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)) { + my $path = "/boot$grub_kernel"; + + # Reconstruct the kernel command line + my @args = (); + foreach my $arg ($g->aug_match("$bootable/kernel/*")) { + $arg =~ m{/kernel/([^/]*)$} + or die("Unexpected return from aug_match: $arg"); + + my $name = $1; + my $value; + eval { $value = $g->aug_get($arg); }; + + if(defined($value)) { + push(@args, "$name=$value"); + } else { + push(@args, $name); + } + } + $config{cmdline} = join(' ', @args) if(scalar(@args) > 0); + + my $kernel = _inspect_linux_kernel($g, $os, "$path"); + + # 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}); + } + } + } - $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} = $path; + + # If this is a packaged kernel, try to work out the name of the package + # which installed it. This lets us know what to install to replace it with, + # e.g. kernel, kernel-smp, kernel-hugemem, kernel-PAE + if($os->{package_format} eq "rpm") { + my $package; + eval { $package = $g->command(['rpm', '-qf', '--qf', + '%{NAME}', $path]); }; + $kernel{package} = $package if defined($package);; + } + + # 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; - $os->{kernels} = \@kernels; + # 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); + + return \%kernel; } # Find all modprobe aliases. Specifically, this looks in the following @@ -1450,28 +1634,14 @@ 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 +1649,7 @@ 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 +1673,40 @@ 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
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