diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 11168006cf..c5254afa7f 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -29,7 +29,9 @@ our $my_uri = $cgi->url(-absolute => 1);
 
 # if we're called with PATH_INFO, we have to strip that
 # from the URL to find our real URL
-if (my $path_info = $ENV{"PATH_INFO"}) {
+# we make $path_info global because it's also used later on
+my $path_info = $ENV{"PATH_INFO"};
+if ($path_info) {
 	$my_url =~ s,\Q$path_info\E$,,;
 	$my_uri =~ s,\Q$path_info\E$,,;
 }
@@ -428,161 +430,42 @@ $projects_list ||= $projectroot;
 
 # ======================================================================
 # input validation and dispatch
-our $action = $cgi->param('a');
-if (defined $action) {
-	if ($action =~ m/[^0-9a-zA-Z\.\-_]/) {
-		die_error(400, "Invalid action parameter");
-	}
-}
 
-# parameters which are pathnames
-our $project = $cgi->param('p');
-if (defined $project) {
-	if (!validate_pathname($project) ||
-	    !(-d "$projectroot/$project") ||
-	    !check_head_link("$projectroot/$project") ||
-	    ($export_ok && !(-e "$projectroot/$project/$export_ok")) ||
-	    ($strict_export && !project_in_list($project))) {
-		undef $project;
-		die_error(404, "No such project");
-	}
-}
+# 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 $file_name = $cgi->param('f');
-if (defined $file_name) {
-	if (!validate_pathname($file_name)) {
-		die_error(400, "Invalid file parameter");
-	}
-}
+my %input_params = ();
 
-our $file_parent = $cgi->param('fp');
-if (defined $file_parent) {
-	if (!validate_pathname($file_parent)) {
-		die_error(400, "Invalid file parent parameter");
-	}
-}
+# 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.
 
-# parameters which are refnames
-our $hash = $cgi->param('h');
-if (defined $hash) {
-	if (!validate_refname($hash)) {
-		die_error(400, "Invalid hash parameter");
-	}
-}
-
-our $hash_parent = $cgi->param('hp');
-if (defined $hash_parent) {
-	if (!validate_refname($hash_parent)) {
-		die_error(400, "Invalid hash parent parameter");
-	}
-}
-
-our $hash_base = $cgi->param('hb');
-if (defined $hash_base) {
-	if (!validate_refname($hash_base)) {
-		die_error(400, "Invalid hash base parameter");
-	}
-}
-
-my %allowed_options = (
-	"--no-merges" => [ qw(rss atom log shortlog history) ],
+my @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",
 );
+my %cgi_param_mapping = @cgi_param_mapping;
 
-our @extra_options = $cgi->param('opt');
-if (defined @extra_options) {
-	foreach my $opt (@extra_options) {
-		if (not exists $allowed_options{$opt}) {
-			die_error(400, "Invalid option parameter");
-		}
-		if (not grep(/^$action$/, @{$allowed_options{$opt}})) {
-			die_error(400, "Invalid option parameter for this action");
-		}
-	}
-}
-
-our $hash_parent_base = $cgi->param('hpb');
-if (defined $hash_parent_base) {
-	if (!validate_refname($hash_parent_base)) {
-		die_error(400, "Invalid hash parent base parameter");
-	}
-}
-
-# other parameters
-our $page = $cgi->param('pg');
-if (defined $page) {
-	if ($page =~ m/[^0-9]/) {
-		die_error(400, "Invalid page parameter");
-	}
-}
-
-our $searchtype = $cgi->param('st');
-if (defined $searchtype) {
-	if ($searchtype =~ m/[^a-z]/) {
-		die_error(400, "Invalid searchtype parameter");
-	}
-}
-
-our $search_use_regexp = $cgi->param('sr');
-
-our $searchtext = $cgi->param('s');
-our $search_regexp;
-if (defined $searchtext) {
-	if (length($searchtext) < 2) {
-		die_error(403, "At least two characters are required for search parameter");
-	}
-	$search_regexp = $search_use_regexp ? $searchtext : quotemeta $searchtext;
-}
-
-# now read PATH_INFO and use it as alternative to parameters
-sub evaluate_path_info {
-	return if defined $project;
-	my $path_info = $ENV{"PATH_INFO"};
-	return if !$path_info;
-	$path_info =~ s,^/+,,;
-	return if !$path_info;
-	# find which part of PATH_INFO is project
-	$project = $path_info;
-	$project =~ s,/+$,,;
-	while ($project && !check_head_link("$projectroot/$project")) {
-		$project =~ s,/*[^/]*$,,;
-	}
-	# validate project
-	$project = validate_pathname($project);
-	if (!$project ||
-	    ($export_ok && !-e "$projectroot/$project/$export_ok") ||
-	    ($strict_export && !project_in_list($project))) {
-		undef $project;
-		return;
-	}
-	# do not change any parameters if an action is given using the query string
-	return if $action;
-	$path_info =~ s,^\Q$project\E/*,,;
-	my ($refname, $pathname) = split(/:/, $path_info, 2);
-	if (defined $pathname) {
-		# we got "project.git/branch:filename" or "project.git/branch:dir/"
-		# we could use git_get_type(branch:pathname), but it needs $git_dir
-		$pathname =~ s,^/+,,;
-		if (!$pathname || substr($pathname, -1) eq "/") {
-			$action  ||= "tree";
-			$pathname =~ s,/$,,;
-		} else {
-			$action  ||= "blob_plain";
-		}
-		$hash_base ||= validate_refname($refname);
-		$file_name ||= validate_pathname($pathname);
-	} elsif (defined $refname) {
-		# we got "project.git/branch"
-		$action ||= "shortlog";
-		$hash   ||= validate_refname($refname);
-	}
-}
-evaluate_path_info();
-
-# path to the current git repository
-our $git_dir;
-$git_dir = "$projectroot/$project" if $project;
-
-# dispatch
+# we will also need to know the possible actions, for validation
 my %actions = (
 	"blame" => \&git_blame,
 	"blobdiff" => \&git_blobdiff,
@@ -613,6 +496,168 @@ my %actions = (
 	"project_index" => \&git_project_index,
 );
 
+# finally, we have the hash of allowed extra_options for the commands that
+# allow them
+my %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
+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/*,,;
+
+	my ($refname, $pathname) = split(/:/, $path_info, 2);
+	if (defined $pathname) {
+		# we got "project.git/branch:filename" or "project.git/branch:dir/"
+		# we could use git_get_type(branch:pathname), but it needs $git_dir
+		$pathname =~ s,^/+,,;
+		if (!$pathname || substr($pathname, -1) eq "/") {
+			$input_params{'action'} = "tree";
+			$pathname =~ s,/$,,;
+		} else {
+			$input_params{'action'} = "blob_plain";
+		}
+		$input_params{'hash_base'} ||= $refname;
+		$input_params{'file_name'} ||= $pathname;
+	} elsif (defined $refname) {
+		# we got "project.git/branch"
+		$input_params{'action'} = "shortlog";
+		$input_params{'hash'} ||= $refname;
+	}
+}
+evaluate_path_info();
+
+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)) {
+		die_error(400, "Invalid file parent parameter");
+	}
+}
+
+# parameters which are refnames
+our $hash = $input_params{'hash'};
+if (defined $hash) {
+	if (!validate_refname($hash)) {
+		die_error(400, "Invalid hash parameter");
+	}
+}
+
+our $hash_parent = $input_params{'hash_parent'};
+if (defined $hash_parent) {
+	if (!validate_refname($hash_parent)) {
+		die_error(400, "Invalid hash parent parameter");
+	}
+}
+
+our $hash_base = $input_params{'hash_base'};
+if (defined $hash_base) {
+	if (!validate_refname($hash_base)) {
+		die_error(400, "Invalid hash base parameter");
+	}
+}
+
+our @extra_options = @{$input_params{'extra_options'}};
+# @extra_options is always defined, since it can only be (currently) set from
+# CGI, and $cgi->param() returns the empty array in array context if the param
+# is not set
+foreach my $opt (@extra_options) {
+	if (not exists $allowed_options{$opt}) {
+		die_error(400, "Invalid option parameter");
+	}
+	if (not grep(/^$action$/, @{$allowed_options{$opt}})) {
+		die_error(400, "Invalid option parameter for this action");
+	}
+}
+
+our $hash_parent_base = $input_params{'hash_parent_base'};
+if (defined $hash_parent_base) {
+	if (!validate_refname($hash_parent_base)) {
+		die_error(400, "Invalid hash parent base parameter");
+	}
+}
+
+# other parameters
+our $page = $input_params{'page'};
+if (defined $page) {
+	if ($page =~ m/[^0-9]/) {
+		die_error(400, "Invalid page parameter");
+	}
+}
+
+our $searchtype = $input_params{'searchtype'};
+if (defined $searchtype) {
+	if ($searchtype =~ m/[^a-z]/) {
+		die_error(400, "Invalid searchtype parameter");
+	}
+}
+
+our $search_use_regexp = $input_params{'search_use_regexp'};
+
+our $searchtext = $input_params{'searchtext'};
+our $search_regexp;
+if (defined $searchtext) {
+	if (length($searchtext) < 2) {
+		die_error(403, "At least two characters are required for search parameter");
+	}
+	$search_regexp = $search_use_regexp ? $searchtext : quotemeta $searchtext;
+}
+
+# path to the current git repository
+our $git_dir;
+$git_dir = "$projectroot/$project" if $project;
+
+# dispatch
 if (!defined $action) {
 	if (defined $hash) {
 		$action = git_get_type($hash);
@@ -642,35 +687,12 @@ sub href (%) {
 	# default is to use -absolute url() i.e. $my_uri
 	my $href = $params{-full} ? $my_url : $my_uri;
 
-	# XXX: Warning: If you touch this, check the search form for updating,
-	# too.
-
-	my @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",
-	);
-	my %mapping = @mapping;
-
 	$params{'project'} = $project unless exists $params{'project'};
 
 	if ($params{-replay}) {
-		while (my ($name, $symbol) = each %mapping) {
+		while (my ($name, $symbol) = each %cgi_param_mapping) {
 			if (!exists $params{$name}) {
-				# to allow for multivalued params we use arrayref form
-				$params{$name} = [ $cgi->param($symbol) ];
+				$params{$name} = $input_params{$name};
 			}
 		}
 	}
@@ -689,8 +711,8 @@ sub href (%) {
 
 	# now encode the parameters explicitly
 	my @result = ();
-	for (my $i = 0; $i < @mapping; $i += 2) {
-		my ($name, $symbol) = ($mapping[$i], $mapping[$i+1]);
+	for (my $i = 0; $i < @cgi_param_mapping; $i += 2) {
+		my ($name, $symbol) = ($cgi_param_mapping[$i], $cgi_param_mapping[$i+1]);
 		if (defined $params{$name}) {
 			if (ref($params{$name}) eq "ARRAY") {
 				foreach my $par (@{$params{$name}}) {
@@ -710,6 +732,25 @@ sub href (%) {
 ## ======================================================================
 ## validation, quoting/unquoting and escaping
 
+sub validate_action {
+	my $input = shift || return undef;
+	return undef unless exists $actions{$input};
+	return $input;
+}
+
+sub validate_project {
+	my $input = shift || return undef;
+	if (!validate_pathname($input) ||
+		!(-d "$projectroot/$input") ||
+		!check_head_link("$projectroot/$input") ||
+		($export_ok && !(-e "$projectroot/$input/$export_ok")) ||
+		($strict_export && !project_in_list($input))) {
+		return undef;
+	} else {
+		return $input;
+	}
+}
+
 sub validate_pathname {
 	my $input = shift || return undef;
 
@@ -4121,7 +4162,7 @@ sub git_search_grep_body {
 ## actions
 
 sub git_project_list {
-	my $order = $cgi->param('o');
+	my $order = $input_params{'order'};
 	if (defined $order && $order !~ m/none|project|descr|owner|age/) {
 		die_error(400, "Unknown order parameter");
 	}
@@ -4149,7 +4190,7 @@ sub git_project_list {
 }
 
 sub git_forks {
-	my $order = $cgi->param('o');
+	my $order = $input_params{'order'};
 	if (defined $order && $order !~ m/none|project|descr|owner|age/) {
 		die_error(400, "Unknown order parameter");
 	}
@@ -4697,7 +4738,7 @@ sub git_snapshot {
 	my @supported_fmts = gitweb_check_feature('snapshot');
 	@supported_fmts = filter_snapshot_fmts(@supported_fmts);
 
-	my $format = $cgi->param('sf');
+	my $format = $input_params{'snapshot_format'};
 	if (!@supported_fmts) {
 		die_error(403, "Snapshots not allowed");
 	}