gitweb.perl

#!/usr/bin/perl

# gitweb - simple web interface to track changes in git repositories
#
# (C) 2005-2006, Kay Sievers <kay.sievers@vrfy.org>
# (C) 2005, Christian Gierke
#
# This program is licensed under the GPLv2

use 5.008;
use strict;
use warnings;

use File::Spec;
# __DIR__ is taken from Dir::Self __DIR__ fragment
sub __DIR__ () {
	File::Spec->rel2abs(join '', (File::Spec->splitpath(__FILE__))[0, 1]);
}
use lib __DIR__ . '/lib';

use CGI qw(:standard :escapeHTML -nosticky);
use CGI::Util qw(unescape);
use CGI::Carp qw(fatalsToBrowser set_message);
use Encode;
use Fcntl ':mode';
use File::Find qw();
use File::Basename qw(basename);
binmode STDOUT, ':utf8';

our $t0;
if (eval { require Time::HiRes; 1; }) {
	$t0 = [Time::HiRes::gettimeofday()];
}
our $number_of_git_cmds = 0;

BEGIN {
	CGI->compile() if $ENV{'MOD_PERL'};
}

our $version = "++GIT_VERSION++";

# Output buffer variable
our $output = "";

our ($my_url, $my_uri, $base_url, $path_info, $home_link);
sub evaluate_uri {
	our $cgi;

	our $my_url = $cgi->url();
	our $my_uri = $cgi->url(-absolute => 1);

	# Base URL for relative URLs in gitweb ($logo, $favicon, ...),
	# needed and used only for URLs with nonempty PATH_INFO
	our $base_url = $my_url;

	# When the script is used as DirectoryIndex, the URL does not contain the name
	# of the script file itself, and $cgi->url() fails to strip PATH_INFO, so we
	# have to do it ourselves. We make $path_info global because it's also used
	# later on.
	#
	# Another issue with the script being the DirectoryIndex is that the resulting
	# $my_url data is not the full script URL: this is good, because we want
	# generated links to keep implying the script name if it wasn't explicitly
	# indicated in the URL we're handling, but it means that $my_url cannot be used
	# as base URL.
	# Therefore, if we needed to strip PATH_INFO, then we know that we have
	# to build the base URL ourselves:
	our $path_info = $ENV{"PATH_INFO"};
	if ($path_info) {
		if ($my_url =~ s,\Q$path_info\E$,, &&
		    $my_uri =~ s,\Q$path_info\E$,, &&
		    defined $ENV{'SCRIPT_NAME'}) {
			$base_url = $cgi->url(-base => 1) . $ENV{'SCRIPT_NAME'};
		}
	}

	# target of the home link on top of all pages
	our $home_link = $my_uri || "/";
}

# core git executable to use
# this can just be "git" if your webserver has a sensible PATH
our $GIT = "++GIT_BINDIR++/git";

# absolute fs-path which will be prepended to the project path
#our $projectroot = "/pub/scm";
our $projectroot = "++GITWEB_PROJECTROOT++";

# fs traversing limit for getting project list
# the number is relative to the projectroot
our $project_maxdepth = "++GITWEB_PROJECT_MAXDEPTH++";

# string of the home link on top of all pages
our $home_link_str = "++GITWEB_HOME_LINK_STR++";

# name of your site or organization to appear in page titles
# replace this with something more descriptive for clearer bookmarks
our $site_name = "++GITWEB_SITENAME++"
                 || ($ENV{'SERVER_NAME'} || "Untitled") . " Git";

# filename of html text to include at top of each page
our $site_header = "++GITWEB_SITE_HEADER++";
# html text to include at home page
our $home_text = "++GITWEB_HOMETEXT++";
# filename of html text to include at bottom of each page
our $site_footer = "++GITWEB_SITE_FOOTER++";

# URI of stylesheets
our @stylesheets = ("++GITWEB_CSS++");
# URI of a single stylesheet, which can be overridden in GITWEB_CONFIG.
our $stylesheet = undef;
# URI of GIT logo (72x27 size)
our $logo = "++GITWEB_LOGO++";
# URI of GIT favicon, assumed to be image/png type
our $favicon = "++GITWEB_FAVICON++";
# URI of gitweb.js (JavaScript code for gitweb)
our $javascript = "++GITWEB_JS++";

# URI and label (title) of GIT logo link
#our $logo_url = "http://www.kernel.org/pub/software/scm/git/docs/";
#our $logo_label = "git documentation";
our $logo_url = "http://git-scm.com/";
our $logo_label = "git homepage";

# source of projects list
our $projects_list = "++GITWEB_LIST++";

# the width (in characters) of the projects list "Description" column
our $projects_list_description_width = 25;

# default order of projects list
# valid values are none, project, descr, owner, and age
our $default_projects_order = "project";

# show repository only if this file exists
# (only effective if this variable evaluates to true)
our $export_ok = "++GITWEB_EXPORT_OK++";

# show repository only if this subroutine returns true
# when given the path to the project, for example:
#    sub { return -e "$_[0]/git-daemon-export-ok"; }
our $export_auth_hook = undef;

# only allow viewing of repositories also shown on the overview page
our $strict_export = "++GITWEB_STRICT_EXPORT++";

# list of git base URLs used for URL to where fetch project from,
# i.e. full URL is "$git_base_url/$project"
our @git_base_url_list = grep { $_ ne '' } ("++GITWEB_BASE_URL++");

# default blob_plain mimetype and default charset for text/plain blob
our $default_blob_plain_mimetype = 'text/plain';
our $default_text_plain_charset  = undef;

# file to use for guessing MIME types before trying /etc/mime.types
# (relative to the current git repository)
our $mimetypes_file = undef;

# assume this charset if line contains non-UTF-8 characters;
# it should be valid encoding (see Encoding::Supported(3pm) for list),
# for which encoding all byte sequences are valid, for example
# 'iso-8859-1' aka 'latin1' (it is decoded without checking, so it
# could be even 'utf-8' for the old behavior)
our $fallback_encoding = 'latin1';

# rename detection options for git-diff and git-diff-tree
# - default is '-M', with the cost proportional to
#   (number of removed files) * (number of new files).
# - more costly is '-C' (which implies '-M'), with the cost proportional to
#   (number of changed files + number of removed files) * (number of new files)
# - even more costly is '-C', '--find-copies-harder' with cost
#   (number of files in the original tree) * (number of new files)
# - one might want to include '-B' option, e.g. '-B', '-M'
our @diff_opts = ('-M'); # taken from git_commit

# Disables features that would allow repository owners to inject script into
# the gitweb domain.
our $prevent_xss = 0;

# Path to the highlight executable to use (must be the one from
# http://www.andre-simon.de due to assumptions about parameters and output).
# Useful if highlight is not installed on your webserver's PATH.
# [Default: highlight]
our $highlight_bin = "++HIGHLIGHT_BIN++";

# information about snapshot formats that gitweb is capable of serving
our %known_snapshot_formats = (
	# name => {
	# 	'display' => display name,
	# 	'type' => mime type,
	# 	'suffix' => filename suffix,
	# 	'format' => --format for git-archive,
	# 	'compressor' => [compressor command and arguments]
	# 	                (array reference, optional)
	# 	'disabled' => boolean (optional)}
	#
	'tgz' => {
		'display' => 'tar.gz',
		'type' => 'application/x-gzip',
		'suffix' => '.tar.gz',
		'format' => 'tar',
		'compressor' => ['gzip']},

	'tbz2' => {
		'display' => 'tar.bz2',
		'type' => 'application/x-bzip2',
		'suffix' => '.tar.bz2',
		'format' => 'tar',
		'compressor' => ['bzip2']},

	'txz' => {
		'display' => 'tar.xz',
		'type' => 'application/x-xz',
		'suffix' => '.tar.xz',
		'format' => 'tar',
		'compressor' => ['xz'],
		'disabled' => 1},

	'zip' => {
		'display' => 'zip',
		'type' => 'application/x-zip',
		'suffix' => '.zip',
		'format' => 'zip'},
);

# Aliases so we understand old gitweb.snapshot values in repository
# configuration.
our %known_snapshot_format_aliases = (
	'gzip'  => 'tgz',
	'bzip2' => 'tbz2',
	'xz'    => 'txz',

	# backward compatibility: legacy gitweb config support
	'x-gzip' => undef, 'gz' => undef,
	'x-bzip2' => undef, 'bz2' => undef,
	'x-zip' => undef, '' => undef,
);

# Pixel sizes for icons and avatars. If the default font sizes or lineheights
# are changed, it may be appropriate to change these values too via
# $GITWEB_CONFIG.
our %avatar_size = (
	'default' => 16,
	'double'  => 32
);

# Used to set the maximum load that we will still respond to gitweb queries.
# If server load exceed this value then return "503 server busy" error.
# If gitweb cannot determined server load, it is taken to be 0.
# Leave it undefined (or set to 'undef') to turn off load checking.
our $maxload = 300;

# This enables/disables the caching layer in gitweb.  This currently only supports the
# 'dumb' file based caching layer, primarily used on git.kernel.org.  this is reasonably
# effective but it has the downside of requiring a huge amount of disk space if there
# are a number of repositories involved.  It is not uncommon for git.kernel.org to have
# on the order of 80G - 120G accumulate over the course of a few months.  It is recommended
# that the cache directory be periodically completely deleted, and this is safe to perform.
# Suggested mechanism
# mv $cacheidr $cachedir.flush;mkdir $cachedir;rm -rf $cachedir.flush
our $caching_enabled = 0;

# Used to set the minimum cache timeout for the dynamic caching algorithm.  Basically
# if we calculate the cache to be under this number of seconds we set the cache timeout
# to this minimum.
# Value is in seconds.  1 = 1 seconds, 60 = 1 minute, 600 = 10 minutes, 3600 = 1 hour
our $minCacheTime = 20;

# Used to set the maximum cache timeout for the dynamic caching algorithm.  Basically
# if we calculate the cache to exceed this number of seconds we set the cache timeout
# to this maximum.
# Value is in seconds.  1 = 1 seconds, 60 = 1 minute, 600 = 10 minutes, 3600 = 1 hour
our $maxCacheTime = 1200;

# If you need to change the location of the caching directory, override this
# otherwise this will probably do fine for you
our $cachedir = 'cache';

# If this is set (to 1) cache will do it's best to always display something instead
# of making someone wait for the cache to update.  This will launch the cacheUpdate
# into the background and it will lock a <file>.bg file and will only lock the
# actual cache file when it needs to write into it.  In theory this will make
# gitweb seem more responsive at the price of possibly stale data.
our $backgroundCache = 1;

# Used to set the maximum cache file life.  If a cache files last modify time exceeds
# this value, it will assume that the data is just too old, and HAS to be regenerated
# instead of trying to display the existing cache data.
# Value is in seconds.  1 = 1 seconds, 60 = 1 minute, 600 = 10 minutes, 3600 = 1 hour
# 18000 = 5 hours
our $maxCacheLife = 18000;

# Used to enable or disable background forking of the gitweb caching.  Mainly here for debugging purposes
our $cacheDoFork = 1;

our $fullhashpath = *STDOUT;
our $fullhashbinpath = *STDOUT;
our $fullhashbinpathfinal = *STDOUT;

# configuration for 'highlight' (http://www.andre-simon.de/)
# match by basename
our %highlight_basename = (
	#'Program' => 'py',
	#'Library' => 'py',
	'SConstruct' => 'py', # SCons equivalent of Makefile
	'Makefile' => 'make',
);
# match by extension
our %highlight_ext = (
	# main extensions, defining name of syntax;
	# see files in /usr/share/highlight/langDefs/ directory
	map { $_ => $_ }
		qw(py c cpp rb java css php sh pl js tex bib xml awk bat ini spec tcl),
	# alternate extensions, see /etc/highlight/filetypes.conf
	'h' => 'c',
	map { $_ => 'cpp' } qw(cxx c++ cc),
	map { $_ => 'php' } qw(php3 php4),
	map { $_ => 'pl'  } qw(perl pm), # perhaps also 'cgi'
	'mak' => 'make',
	map { $_ => 'xml' } qw(xhtml html htm),
);

# You define site-wide feature defaults here; override them with
# $GITWEB_CONFIG as necessary.
our %feature = (
	# feature => {
	# 	'sub' => feature-sub (subroutine),
	# 	'override' => allow-override (boolean),
	# 	'default' => [ default options...] (array reference)}
	#
	# if feature is overridable (it means that allow-override has true value),
	# then feature-sub will be called with default options as parameters;
	# return value of feature-sub indicates if to enable specified feature
	#
	# if there is no 'sub' key (no feature-sub), then feature cannot be
	# overridden
	#
	# use gitweb_get_feature(<feature>) to retrieve the <feature> value
	# (an array) or gitweb_check_feature(<feature>) to check if <feature>
	# is enabled

	# Enable the 'blame' blob view, showing the last commit that modified
	# each line in the file. This can be very CPU-intensive.

	# To enable system wide have in $GITWEB_CONFIG
	# $feature{'blame'}{'default'} = [1];
	# To have project specific config enable override in $GITWEB_CONFIG
	# $feature{'blame'}{'override'} = 1;
	# and in project config gitweb.blame = 0|1;
	'blame' => {
		'sub' => sub { feature_bool('blame', @_) },
		'override' => 0,
		'default' => [0]},

	# Enable the 'snapshot' link, providing a compressed archive of any
	# tree. This can potentially generate high traffic if you have large
	# project.

	# Value is a list of formats defined in %known_snapshot_formats that
	# you wish to offer.
	# To disable system wide have in $GITWEB_CONFIG
	# $feature{'snapshot'}{'default'} = [];
	# To have project specific config enable override in $GITWEB_CONFIG
	# $feature{'snapshot'}{'override'} = 1;
	# and in project config, a comma-separated list of formats or "none"
	# to disable.  Example: gitweb.snapshot = tbz2,zip;
	'snapshot' => {
		'sub' => \&feature_snapshot,
		'override' => 0,
		'default' => ['tgz']},

	# Enable text search, which will list the commits which match author,
	# committer or commit text to a given string.  Enabled by default.
	# Project specific override is not supported.
	'search' => {
		'override' => 0,
		'default' => [1]},

	# Enable grep search, which will list the files in currently selected
	# tree containing the given string. Enabled by default. This can be
	# potentially CPU-intensive, of course.

	# To enable system wide have in $GITWEB_CONFIG
	# $feature{'grep'}{'default'} = [1];
	# To have project specific config enable override in $GITWEB_CONFIG
	# $feature{'grep'}{'override'} = 1;
	# and in project config gitweb.grep = 0|1;
	'grep' => {
		'sub' => sub { feature_bool('grep', @_) },
		'override' => 0,
		'default' => [1]},

	# Enable the pickaxe search, which will list the commits that modified
	# a given string in a file. This can be practical and quite faster
	# alternative to 'blame', but still potentially CPU-intensive.

	# To enable system wide have in $GITWEB_CONFIG
	# $feature{'pickaxe'}{'default'} = [1];
	# To have project specific config enable override in $GITWEB_CONFIG
	# $feature{'pickaxe'}{'override'} = 1;
	# and in project config gitweb.pickaxe = 0|1;
	'pickaxe' => {
		'sub' => sub { feature_bool('pickaxe', @_) },
		'override' => 0,
		'default' => [1]},

	# Enable showing size of blobs in a 'tree' view, in a separate
	# column, similar to what 'ls -l' does.  This cost a bit of IO.

	# To disable system wide have in $GITWEB_CONFIG
	# $feature{'show-sizes'}{'default'} = [0];
	# To have project specific config enable override in $GITWEB_CONFIG
	# $feature{'show-sizes'}{'override'} = 1;
	# and in project config gitweb.showsizes = 0|1;
	'show-sizes' => {
		'sub' => sub { feature_bool('showsizes', @_) },
		'override' => 0,
		'default' => [1]},

	# Make gitweb use an alternative format of the URLs which can be
	# more readable and natural-looking: project name is embedded
	# directly in the path and the query string contains other
	# auxiliary information. All gitweb installations recognize
	# URL in either format; this configures in which formats gitweb
	# generates links.

	# To enable system wide have in $GITWEB_CONFIG
	# $feature{'pathinfo'}{'default'} = [1];
	# Project specific override is not supported.

	# Note that you will need to change the default location of CSS,
	# favicon, logo and possibly other files to an absolute URL. Also,
	# if gitweb.cgi serves as your indexfile, you will need to force
	# $my_uri to contain the script name in your $GITWEB_CONFIG.
	'pathinfo' => {
		'override' => 0,
		'default' => [0]},

	# Make gitweb consider projects in project root subdirectories
	# to be forks of existing projects. Given project $projname.git,
	# projects matching $projname/*.git will not be shown in the main
	# projects list, instead a '+' mark will be added to $projname
	# there and a 'forks' view will be enabled for the project, listing
	# all the forks. If project list is taken from a file, forks have
	# to be listed after the main project.

	# To enable system wide have in $GITWEB_CONFIG
	# $feature{'forks'}{'default'} = [1];
	# Project specific override is not supported.
	'forks' => {
		'override' => 0,
		'default' => [0]},

	# Insert custom links to the action bar of all project pages.
	# This enables you mainly to link to third-party scripts integrating
	# into gitweb; e.g. git-browser for graphical history representation
	# or custom web-based repository administration interface.

	# The 'default' value consists of a list of triplets in the form
	# (label, link, position) where position is the label after which
	# to insert the link and link is a format string where %n expands
	# to the project name, %f to the project path within the filesystem,
	# %h to the current hash (h gitweb parameter) and %b to the current
	# hash base (hb gitweb parameter); %% expands to %.

	# To enable system wide have in $GITWEB_CONFIG e.g.
	# $feature{'actions'}{'default'} = [('graphiclog',
	# 	'/git-browser/by-commit.html?r=%n', 'summary')];
	# Project specific override is not supported.
	'actions' => {
		'override' => 0,
		'default' => []},

	# Allow gitweb scan project content tags described in ctags/
	# of project repository, and display the popular Web 2.0-ish
	# "tag cloud" near the project list. Note that this is something
	# COMPLETELY different from the normal Git tags.

	# gitweb by itself can show existing tags, but it does not handle
	# tagging itself; you need an external application for that.
	# For an example script, check Girocco's cgi/tagproj.cgi.
	# You may want to install the HTML::TagCloud Perl module to get
	# a pretty tag cloud instead of just a list of tags.

	# To enable system wide have in $GITWEB_CONFIG
	# $feature{'ctags'}{'default'} = ['path_to_tag_script'];
	# Project specific override is not supported.
	'ctags' => {
		'override' => 0,
		'default' => [0]},

	# The maximum number of patches in a patchset generated in patch
	# view. Set this to 0 or undef to disable patch view, or to a
	# negative number to remove any limit.

	# To disable system wide have in $GITWEB_CONFIG
	# $feature{'patches'}{'default'} = [0];
	# To have project specific config enable override in $GITWEB_CONFIG
	# $feature{'patches'}{'override'} = 1;
	# and in project config gitweb.patches = 0|n;
	# where n is the maximum number of patches allowed in a patchset.
	'patches' => {
		'sub' => \&feature_patches,
		'override' => 0,
		'default' => [16]},

	# Avatar support. When this feature is enabled, views such as
	# shortlog or commit will display an avatar associated with
	# the email of the committer(s) and/or author(s).

	# Currently available providers are gravatar and picon.
	# If an unknown provider is specified, the feature is disabled.

	# Gravatar depends on Digest::MD5.
	# Picon currently relies on the indiana.edu database.

	# To enable system wide have in $GITWEB_CONFIG
	# $feature{'avatar'}{'default'} = ['<provider>'];
	# where <provider> is either gravatar or picon.
	# To have project specific config enable override in $GITWEB_CONFIG
	# $feature{'avatar'}{'override'} = 1;
	# and in project config gitweb.avatar = <provider>;
	'avatar' => {
		'sub' => \&feature_avatar,
		'override' => 0,
		'default' => ['']},

	# Enable displaying how much time and how many git commands
	# it took to generate and display page.  Disabled by default.
	# Project specific override is not supported.
	'timed' => {
		'override' => 0,
		'default' => [0]},

	# Enable turning some links into links to actions which require
	# JavaScript to run (like 'blame_incremental').  Not enabled by
	# default.  Project specific override is currently not supported.
	'javascript-actions' => {
		'override' => 0,
		'default' => [0]},

	# Syntax highlighting support. This is based on Daniel Svensson's
	# and Sham Chukoury's work in gitweb-xmms2.git.
	# It requires the 'highlight' program present in $PATH,
	# and therefore is disabled by default.

	# To enable system wide have in $GITWEB_CONFIG
	# $feature{'highlight'}{'default'} = [1];

	'highlight' => {
		'sub' => sub { feature_bool('highlight', @_) },
		'override' => 0,
		'default' => [0]},
);

#
# Includes
#
if (!exists $INC{'cache.pl'}) {
	my $return = do 'cache.pl';
	die $@ if $@;
	die "Couldn't read 'cache.pl': $!" if (!defined $return);
}

sub gitweb_get_feature {
	my ($name) = @_;
	return unless exists $feature{$name};
	my ($sub, $override, @defaults) = (
		$feature{$name}{'sub'},
		$feature{$name}{'override'},
		@{$feature{$name}{'default'}});
	# project specific override is possible only if we have project
	our $git_dir; # global variable, declared later
	if (!$override || !defined $git_dir) {
		return @defaults;
	}
	if (!defined $sub) {
		warn "feature $name is not overridable";
		return @defaults;
	}
	return $sub->(@defaults);
}

# A wrapper to check if a given feature is enabled.
# With this, you can say
#
#   my $bool_feat = gitweb_check_feature('bool_feat');
#   gitweb_check_feature('bool_feat') or somecode;
#
# instead of
#
#   my ($bool_feat) = gitweb_get_feature('bool_feat');
#   (gitweb_get_feature('bool_feat'))[0] or somecode;
#
sub gitweb_check_feature {
	return (gitweb_get_feature(@_))[0];
}


sub feature_bool {
	my $key = shift;
	my ($val) = git_get_project_config($key, '--bool');

	if (!defined $val) {
		return ($_[0]);
	} elsif ($val eq 'true') {
		return (1);
	} elsif ($val eq 'false') {
		return (0);
	}
}

sub feature_snapshot {
	my (@fmts) = @_;

	my ($val) = git_get_project_config('snapshot');

	if ($val) {
		@fmts = ($val eq 'none' ? () : split /\s*[,\s]\s*/, $val);
	}

	return @fmts;
}

sub feature_patches {
	my @val = (git_get_project_config('patches', '--int'));

	if (@val) {
		return @val;
	}

	return ($_[0]);
}

sub feature_avatar {
	my @val = (git_get_project_config('avatar'));

	return @val ? @val : @_;
}

# checking HEAD file with -e is fragile if the repository was
# initialized long time ago (i.e. symlink HEAD) and was pack-ref'ed
# and then pruned.
sub check_head_link {
	my ($dir) = @_;
	my $headfile = "$dir/HEAD";
	return ((-e $headfile) ||
		(-l $headfile && readlink($headfile) =~ /^refs\/heads\//));
}

sub check_export_ok {
	my ($dir) = @_;
	return (check_head_link($dir) &&
		(!$export_ok || -e "$dir/$export_ok") &&
		(!$export_auth_hook || $export_auth_hook->($dir)));
}

# process alternate names for backward compatibility
# filter out unsupported (unknown) snapshot formats
sub filter_snapshot_fmts {
	my @fmts = @_;

	@fmts = map {
		exists $known_snapshot_format_aliases{$_} ?
		       $known_snapshot_format_aliases{$_} : $_} @fmts;
	@fmts = grep {
		exists $known_snapshot_formats{$_} &&
		!$known_snapshot_formats{$_}{'disabled'}} @fmts;
}

our ($GITWEB_CONFIG, $GITWEB_CONFIG_SYSTEM);
sub evaluate_gitweb_config {
	our $GITWEB_CONFIG = $ENV{'GITWEB_CONFIG'} || "++GITWEB_CONFIG++";
	our $GITWEB_CONFIG_SYSTEM = $ENV{'GITWEB_CONFIG_SYSTEM'} || "++GITWEB_CONFIG_SYSTEM++";
	# die if there are errors parsing config file
	if (-e $GITWEB_CONFIG) {
		do $GITWEB_CONFIG;
		die $@ if $@;
	} elsif (-e $GITWEB_CONFIG_SYSTEM) {
		do $GITWEB_CONFIG_SYSTEM;
		die $@ if $@;
	}
}

# Get loadavg of system, to compare against $maxload.
# Currently it requires '/proc/loadavg' present to get loadavg;
# if it is not present it returns 0, which means no load checking.
sub get_loadavg {
	if( -e '/proc/loadavg' ){
		open my $fd, '<', '/proc/loadavg'
			or return 0;
		my @load = split(/\s+/, scalar <$fd>);
		close $fd;

		# The first three columns measure CPU and IO utilization of the last one,
		# five, and 10 minute periods.  The fourth column shows the number of
		# currently running processes and the total number of processes in the m/n
		# format.  The last column displays the last process ID used.
		return $load[0] || 0;
	}
	# additional checks for load average should go here for things that don't export
	# /proc/loadavg

	return 0;
}

# version of the core git binary
our $git_version;
sub evaluate_git_version {
	our $git_version = qx("$GIT" --version) =~ m/git version (.*)$/ ? $1 : "unknown";
	$number_of_git_cmds++;
}

sub check_loadavg {
	if (defined $maxload && get_loadavg() > $maxload) {
		die_error(503, "The load average on the server is too high");
	}
}

# ======================================================================
# input validation and dispatch

# input parameters can be collected from a variety of sources (presently, CGI
# and PATH_INFO), so we define an %input_params hash that collects them all
# together during validation: this allows subsequent uses (e.g. href()) to be
# agnostic of the parameter origin

our %input_params = ();

# input parameters are stored with the long parameter name as key. This will
# also be used in the href subroutine to convert parameters to their CGI
# equivalent, and since the href() usage is the most frequent one, we store
# the name -> CGI key mapping here, instead of the reverse.
#
# XXX: Warning: If you touch this, check the search form for updating,
# too.

our @cgi_param_mapping = (
	project => "p",
	action => "a",
	file_name => "f",
	file_parent => "fp",
	hash => "h",
	hash_parent => "hp",
	hash_base => "hb",
	hash_parent_base => "hpb",
	page => "pg",
	order => "o",
	searchtext => "s",
	searchtype => "st",
	snapshot_format => "sf",
	extra_options => "opt",
	search_use_regexp => "sr",
	# this must be last entry (for manipulation from JavaScript)
	javascript => "js"
);
our %cgi_param_mapping = @cgi_param_mapping;

# we will also need to know the possible actions, for validation
our %actions = (
	"blame" => \&git_blame,
	"blame_incremental" => \&git_blame_incremental,
	"blame_data" => \&git_blame_data,
	"blobdiff" => \&git_blobdiff,
	"blobdiff_plain" => \&git_blobdiff_plain,
	"blob" => \&git_blob,
	"blob_plain" => \&git_blob_plain,
	"commitdiff" => \&git_commitdiff,
	"commitdiff_plain" => \&git_commitdiff_plain,
	"commit" => \&git_commit,
	"forks" => \&git_forks,
	"heads" => \&git_heads,
	"history" => \&git_history,
	"log" => \&git_log,
	"patch" => \&git_patch,
	"patches" => \&git_patches,
	"rss" => \&git_rss,
	"atom" => \&git_atom,
	"search" => \&git_search,
	"search_help" => \&git_search_help,
	"shortlog" => \&git_shortlog,
	"summary" => \&git_summary,
	"tag" => \&git_tag,
	"tags" => \&git_tags,
	"tree" => \&git_tree,
	"snapshot" => \&git_snapshot,
	"object" => \&git_object,
	# those below don't need $project
	"opml" => \&git_opml,
	"project_list" => \&git_project_list,
	"project_index" => \&git_project_index,
);
sub is_cacheable {
	my $action = shift;
	return !($action eq 'blame_data' || $action eq 'blame_incremental');
}

# finally, we have the hash of allowed extra_options for the commands that
# allow them
our %allowed_options = (
	"--no-merges" => [ qw(rss atom log shortlog history) ],
);

# fill %input_params with the CGI parameters. All values except for 'opt'
# should be single values, but opt can be an array. We should probably
# build an array of parameters that can be multi-valued, but since for the time
# being it's only this one, we just single it out
sub evaluate_query_params {
	our $cgi;

	while (my ($name, $symbol) = each %cgi_param_mapping) {
		if ($symbol eq 'opt') {
			$input_params{$name} = [ $cgi->param($symbol) ];
		} else {
			$input_params{$name} = $cgi->param($symbol);
		}
	}
}

# now read PATH_INFO and update the parameter list for missing parameters
sub evaluate_path_info {
	return if defined $input_params{'project'};
	return if !$path_info;
	$path_info =~ s,^/+,,;
	return if !$path_info;

	# find which part of PATH_INFO is project
	my $project = $path_info;
	$project =~ s,/+$,,;
	while ($project && !check_head_link("$projectroot/$project")) {
		$project =~ s,/*[^/]*$,,;
	}
	return unless $project;
	$input_params{'project'} = $project;

	# do not change any parameters if an action is given using the query string
	return if $input_params{'action'};
	$path_info =~ s,^\Q$project\E/*,,;

	# next, check if we have an action
	my $action = $path_info;
	$action =~ s,/.*$,,;
	if (exists $actions{$action}) {
		$path_info =~ s,^$action/*,,;
		$input_params{'action'} = $action;
	}

	# list of actions that want hash_base instead of hash, but can have no
	# pathname (f) parameter
	my @wants_base = (
		'tree',
		'history',
	);

	# we want to catch, among others
	# [$hash_parent_base[:$file_parent]..]$hash_parent[:$file_name]
	my ($parentrefname, $parentpathname, $refname, $pathname) =
		($path_info =~ /^(?:(.+?)(?::(.+))?\.\.)?([^:]+?)?(?::(.+))?$/);

	# first, analyze the 'current' part
	if (defined $pathname) {
		# we got "branch:filename" or "branch:dir/"
		# we could use git_get_type(branch:pathname), but:
		# - it needs $git_dir
		# - it does a git() call
		# - the convention of terminating directories with a slash
		#   makes it superfluous
		# - embedding the action in the PATH_INFO would make it even
		#   more superfluous
		$pathname =~ s,^/+,,;
		if (!$pathname || substr($pathname, -1) eq "/") {
			$input_params{'action'} ||= "tree";
			$pathname =~ s,/$,,;
		} else {
			# the default action depends on whether we had parent info
			# or not
			if ($parentrefname) {
				$input_params{'action'} ||= "blobdiff_plain";
			} else {
				$input_params{'action'} ||= "blob_plain";
			}
		}
		$input_params{'hash_base'} ||= $refname;
		$input_params{'file_name'} ||= $pathname;
	} elsif (defined $refname) {
		# we got "branch". In this case we have to choose if we have to
		# set hash or hash_base.
		#
		# Most of the actions without a pathname only want hash to be
		# set, except for the ones specified in @wants_base that want
		# hash_base instead. It should also be noted that hand-crafted
		# links having 'history' as an action and no pathname or hash
		# set will fail, but that happens regardless of PATH_INFO.
		if (defined $parentrefname) {
			# if there is parent let the default be 'shortlog' action
			# (for http://git.example.com/repo.git/A..B links); if there
			# is no parent, dispatch will detect type of object and set
			# action appropriately if required (if action is not set)
			$input_params{'action'} ||= "shortlog";
		}
		if ($input_params{'action'} &&
		    grep { $_ eq $input_params{'action'} } @wants_base) {
			$input_params{'hash_base'} ||= $refname;
		} else {
			$input_params{'hash'} ||= $refname;
		}
	}

	# next, handle the 'parent' part, if present
	if (defined $parentrefname) {
		# a missing pathspec defaults to the 'current' filename, allowing e.g.
		# someproject/blobdiff/oldrev..newrev:/filename
		if ($parentpathname) {
			$parentpathname =~ s,^/+,,;
			$parentpathname =~ s,/$,,;
			$input_params{'file_parent'} ||= $parentpathname;
		} else {
			$input_params{'file_parent'} ||= $input_params{'file_name'};
		}
		# we assume that hash_parent_base is wanted if a path was specified,
		# or if the action wants hash_base instead of hash
		if (defined $input_params{'file_parent'} ||
			grep { $_ eq $input_params{'action'} } @wants_base) {
			$input_params{'hash_parent_base'} ||= $parentrefname;
		} else {
			$input_params{'hash_parent'} ||= $parentrefname;
		}
	}

	# for the snapshot action, we allow URLs in the form
	# $project/snapshot/$hash.ext
	# where .ext determines the snapshot and gets removed from the
	# passed $refname to provide the $hash.
	#
	# To be able to tell that $refname includes the format extension, we
	# require the following two conditions to be satisfied:
	# - the hash input parameter MUST have been set from the $refname part
	#   of the URL (i.e. they must be equal)
	# - the snapshot format MUST NOT have been defined already (e.g. from
	#   CGI parameter sf)
	# It's also useless to try any matching unless $refname has a dot,
	# so we check for that too
	if (defined $input_params{'action'} &&
		$input_params{'action'} eq 'snapshot' &&
		defined $refname && index($refname, '.') != -1 &&
		$refname eq $input_params{'hash'} &&
		!defined $input_params{'snapshot_format'}) {
		# We loop over the known snapshot formats, checking for
		# extensions. Allowed extensions are both the defined suffix
		# (which includes the initial dot already) and the snapshot
		# format key itself, with a prepended dot
		while (my ($fmt, $opt) = each %known_snapshot_formats) {
			my $hash = $refname;
			unless ($hash =~ s/(\Q$opt->{'suffix'}\E|\Q.$fmt\E)$//) {
				next;
			}
			my $sfx = $1;
			# a valid suffix was found, so set the snapshot format
			# and reset the hash parameter
			$input_params{'snapshot_format'} = $fmt;
			$input_params{'hash'} = $hash;
			# we also set the format suffix to the one requested
			# in the URL: this way a request for e.g. .tgz returns
			# a .tgz instead of a .tar.gz
			$known_snapshot_formats{$fmt}{'suffix'} = $sfx;
			last;
		}
	}
}

our ($action, $project, $file_name, $file_parent, $hash, $hash_parent, $hash_base,
     $hash_parent_base, @extra_options, $page, $searchtype, $search_use_regexp,
     $searchtext, $search_regexp);
sub evaluate_and_validate_params {
	our $action = $input_params{'action'};
	if (defined $action) {
		if (!validate_action($action)) {
			die_error(400, "Invalid action parameter");
		}
	}

	# parameters which are pathnames
	our $project = $input_params{'project'};
	if (defined $project) {
		if (!validate_project($project)) {
			undef $project;
			die_error(404, "No such project");
		}
	}

	our $file_name = $input_params{'file_name'};
	if (defined $file_name) {
		if (!validate_pathname($file_name)) {
			die_error(400, "Invalid file parameter");
		}
	}

	our $file_parent = $input_params{'file_parent'};
	if (defined $file_parent) {
		if (!validate_pathname($file_parent)) {