merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

Merge commit '1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5' as 'third_party/git'

1 files changed, 421 insertions, 0 deletions

diff --git a/third_party/git/contrib/hooks/update-paranoid b/third_party/git/contrib/hooks/update-paranoid
new file mode 100755
index 000000000000..d18b317b2f01
--- /dev/null
+++ b/third_party/git/contrib/hooks/update-paranoid
@@ -0,0 +1,421 @@
+#!/usr/bin/perl
+
+use strict;
+use File::Spec;
+
+$ENV{PATH}     = '/opt/git/bin';
+my $acl_git    = '/vcs/acls.git';
+my $acl_branch = 'refs/heads/master';
+my $debug      = 0;
+
+=doc
+Invoked as: update refname old-sha1 new-sha1
+
+This script is run by git-receive-pack once for each ref that the
+client is trying to modify.  If we exit with a non-zero exit value
+then the update for that particular ref is denied, but updates for
+other refs in the same run of receive-pack may still be allowed.
+
+We are run after the objects have been uploaded, but before the
+ref is actually modified.  We take advantage of that fact when we
+look for "new" commits and tags (the new objects won't show up in
+`rev-list --all`).
+
+This script loads and parses the content of the config file
+"users/$this_user.acl" from the $acl_branch commit of $acl_git ODB.
+The acl file is a git-config style file, but uses a slightly more
+restricted syntax as the Perl parser contained within this script
+is not nearly as permissive as git-config.
+
+Example:
+
+  [user]
+    committer = John Doe <john.doe@example.com>
+    committer = John R. Doe <john.doe@example.com>
+
+  [repository "acls"]
+    allow = heads/master
+    allow = CDUR for heads/jd/
+    allow = C    for ^tags/v\\d+$
+
+For all new commit or tag objects the committer (or tagger) line
+within the object must exactly match one of the user.committer
+values listed in the acl file ("HEAD:users/$this_user.acl").
+
+For a branch to be modified an allow line within the matching
+repository section must be matched for both the refname and the
+opcode.
+
+Repository sections are matched on the basename of the repository
+(after removing the .git suffix).
+
+The opcode abbrevations are:
+
+  C: create new ref
+  D: delete existing ref
+  U: fast-forward existing ref (no commit loss)
+  R: rewind/rebase existing ref (commit loss)
+
+if no opcodes are listed before the "for" keyword then "U" (for
+fast-forward update only) is assumed as this is the most common
+usage.
+
+Refnames are matched by always assuming a prefix of "refs/".
+This hook forbids pushing or deleting anything not under "refs/".
+
+Refnames that start with ^ are Perl regular expressions, and the ^
+is kept as part of the regexp.  \\ is needed to get just one \, so
+\\d expands to \d in Perl.  The 3rd allow line above is an example.
+
+Refnames that don't start with ^ but that end with / are prefix
+matches (2nd allow line above); all other refnames are strict
+equality matches (1st allow line).
+
+Anything pushed to "heads/" (ok, really "refs/heads/") must be
+a commit.  Tags are not permitted here.
+
+Anything pushed to "tags/" (err, really "refs/tags/") must be an
+annotated tag.  Commits, blobs, trees, etc. are not permitted here.
+Annotated tag signatures aren't checked, nor are they required.
+
+The special subrepository of 'info/new-commit-check' can
+be created and used to allow users to push new commits and
+tags from another local repository to this one, even if they
+aren't the committer/tagger of those objects.  In a nut shell
+the info/new-commit-check directory is a Git repository whose
+objects/info/alternates file lists this repository and all other
+possible sources, and whose refs subdirectory contains symlinks
+to this repository's refs subdirectory, and to all other possible
+sources refs subdirectories.  Yes, this means that you cannot
+use packed-refs in those repositories as they won't be resolved
+correctly.
+
+=cut
+
+my $git_dir = $ENV{GIT_DIR};
+my $new_commit_check = "$git_dir/info/new-commit-check";
+my $ref = $ARGV[0];
+my $old = $ARGV[1];
+my $new = $ARGV[2];
+my $new_type;
+my ($this_user) = getpwuid $<; # REAL_USER_ID
+my $repository_name;
+my %user_committer;
+my @allow_rules;
+my @path_rules;
+my %diff_cache;
+
+sub deny ($) {
+	print STDERR "-Deny-    $_[0]\n" if $debug;
+	print STDERR "\ndenied: $_[0]\n\n";
+	exit 1;
+}
+
+sub grant ($) {
+	print STDERR "-Grant-   $_[0]\n" if $debug;
+	exit 0;
+}
+
+sub info ($) {
+	print STDERR "-Info-    $_[0]\n" if $debug;
+}
+
+sub git_value (@) {
+	open(T,'-|','git',@_); local $_ = <T>; chop; close T; $_;
+}
+
+sub match_string ($$) {
+	my ($acl_n, $ref) = @_;
+	   ($acl_n eq $ref)
+	|| ($acl_n =~ m,/$, && substr($ref,0,length $acl_n) eq $acl_n)
+	|| ($acl_n =~ m,^\^, && $ref =~ m:$acl_n:);
+}
+
+sub parse_config ($$$$) {
+	my $data = shift;
+	local $ENV{GIT_DIR} = shift;
+	my $br = shift;
+	my $fn = shift;
+	return unless git_value('rev-list','--max-count=1',$br,'--',$fn);
+	info "Loading $br:$fn";
+	open(I,'-|','git','cat-file','blob',"$br:$fn");
+	my $section = '';
+	while (<I>) {
+		chomp;
+		if (/^\s*$/ || /^\s*#/) {
+		} elsif (/^\[([a-z]+)\]$/i) {
+			$section = lc $1;
+		} elsif (/^\[([a-z]+)\s+"(.*)"\]$/i) {
+			$section = join('.',lc $1,$2);
+		} elsif (/^\s*([a-z][a-z0-9]+)\s*=\s*(.*?)\s*$/i) {
+			push @{$data->{join('.',$section,lc $1)}}, $2;
+		} else {
+			deny "bad config file line $. in $br:$fn";
+		}
+	}
+	close I;
+}
+
+sub all_new_committers () {
+	local $ENV{GIT_DIR} = $git_dir;
+	$ENV{GIT_DIR} = $new_commit_check if -d $new_commit_check;
+
+	info "Getting committers of new commits.";
+	my %used;
+	open(T,'-|','git','rev-list','--pretty=raw',$new,'--not','--all');
+	while (<T>) {
+		next unless s/^committer //;
+		chop;
+		s/>.*$/>/;
+		info "Found $_." unless $used{$_}++;
+	}
+	close T;
+	info "No new commits." unless %used;
+	keys %used;
+}
+
+sub all_new_taggers () {
+	my %exists;
+	open(T,'-|','git','for-each-ref','--format=%(objectname)','refs/tags');
+	while (<T>) {
+		chop;
+		$exists{$_} = 1;
+	}
+	close T;
+
+	info "Getting taggers of new tags.";
+	my %used;
+	my $obj = $new;
+	my $obj_type = $new_type;
+	while ($obj_type eq 'tag') {
+		last if $exists{$obj};
+		$obj_type = '';
+		open(T,'-|','git','cat-file','tag',$obj);
+		while (<T>) {
+			chop;
+			if (/^object ([a-z0-9]{40})$/) {
+				$obj = $1;
+			} elsif (/^type (.+)$/) {
+				$obj_type = $1;
+			} elsif (s/^tagger //) {
+				s/>.*$/>/;
+				info "Found $_." unless $used{$_}++;
+				last;
+			}
+		}
+		close T;
+	}
+	info "No new tags." unless %used;
+	keys %used;
+}
+
+sub check_committers (@) {
+	my @bad;
+	foreach (@_) { push @bad, $_ unless $user_committer{$_}; }
+	if (@bad) {
+		print STDERR "\n";
+		print STDERR "You are not $_.\n" foreach (sort @bad);
+		deny "You cannot push changes not committed by you.";
+	}
+}
+
+sub load_diff ($) {
+	my $base = shift;
+	my $d = $diff_cache{$base};
+	unless ($d) {
+		local $/ = "\0";
+		my %this_diff;
+		if ($base =~ /^0{40}$/) {
+			# Don't load the diff at all; we are making the
+			# branch and have no base to compare to in this
+			# case.  A file level ACL makes no sense in this
+			# context.  Having an empty diff will allow the
+			# branch creation.
+			#
+		} else {
+			open(T,'-|','git','diff-tree',
+				'-r','--name-status','-z',
+				$base,$new) or return undef;
+			while (<T>) {
+				my $op = $_;
+				chop $op;
+
+				my $path = <T>;
+				chop $path;
+
+				$this_diff{$path} = $op;
+			}
+			close T or return undef;
+		}
+		$d = \%this_diff;
+		$diff_cache{$base} = $d;
+	}
+	return $d;
+}
+
+deny "No GIT_DIR inherited from caller" unless $git_dir;
+deny "Need a ref name" unless $ref;
+deny "Refusing funny ref $ref" unless $ref =~ s,^refs/,,;
+deny "Bad old value $old" unless $old =~ /^[a-z0-9]{40}$/;
+deny "Bad new value $new" unless $new =~ /^[a-z0-9]{40}$/;
+deny "Cannot determine who you are." unless $this_user;
+grant "No change requested." if $old eq $new;
+
+$repository_name = File::Spec->rel2abs($git_dir);
+$repository_name =~ m,/([^/]+)(?:\.git|/\.git)$,;
+$repository_name = $1;
+info "Updating in '$repository_name'.";
+
+my $op;
+if    ($old =~ /^0{40}$/) { $op = 'C'; }
+elsif ($new =~ /^0{40}$/) { $op = 'D'; }
+else                      { $op = 'R'; }
+
+# This is really an update (fast-forward) if the
+# merge base of $old and $new is $old.
+#
+$op = 'U' if ($op eq 'R'
+	&& $ref =~ m,^heads/,
+	&& $old eq git_value('merge-base',$old,$new));
+
+# Load the user's ACL file. Expand groups (user.memberof) one level.
+{
+	my %data = ('user.committer' => []);
+	parse_config(\%data,$acl_git,$acl_branch,"external/$repository_name.acl");
+
+	%data = (
+		'user.committer' => $data{'user.committer'},
+		'user.memberof' => [],
+	);
+	parse_config(\%data,$acl_git,$acl_branch,"users/$this_user.acl");
+
+	%user_committer = map {$_ => $_} @{$data{'user.committer'}};
+	my $rule_key = "repository.$repository_name.allow";
+	my $rules = $data{$rule_key} || [];
+
+	foreach my $group (@{$data{'user.memberof'}}) {
+		my %g;
+		parse_config(\%g,$acl_git,$acl_branch,"groups/$group.acl");
+		my $group_rules = $g{$rule_key};
+		push @$rules, @$group_rules if $group_rules;
+	}
+
+RULE:
+	foreach (@$rules) {
+		while (/\${user\.([a-z][a-zA-Z0-9]+)}/) {
+			my $k = lc $1;
+			my $v = $data{"user.$k"};
+			next RULE unless defined $v;
+			next RULE if @$v != 1;
+			next RULE unless defined $v->[0];
+			s/\${user\.$k}/$v->[0]/g;
+		}
+
+		if (/^([AMD ]+)\s+of\s+([^\s]+)\s+for\s+([^\s]+)\s+diff\s+([^\s]+)$/) {
+			my ($ops, $pth, $ref, $bst) = ($1, $2, $3, $4);
+			$ops =~ s/ //g;
+			$pth =~ s/\\\\/\\/g;
+			$ref =~ s/\\\\/\\/g;
+			push @path_rules, [$ops, $pth, $ref, $bst];
+		} elsif (/^([AMD ]+)\s+of\s+([^\s]+)\s+for\s+([^\s]+)$/) {
+			my ($ops, $pth, $ref) = ($1, $2, $3);
+			$ops =~ s/ //g;
+			$pth =~ s/\\\\/\\/g;
+			$ref =~ s/\\\\/\\/g;
+			push @path_rules, [$ops, $pth, $ref, $old];
+		} elsif (/^([CDRU ]+)\s+for\s+([^\s]+)$/) {
+			my $ops = $1;
+			my $ref = $2;
+			$ops =~ s/ //g;
+			$ref =~ s/\\\\/\\/g;
+			push @allow_rules, [$ops, $ref];
+		} elsif (/^for\s+([^\s]+)$/) {
+			# Mentioned, but nothing granted?
+		} elsif (/^[^\s]+$/) {
+			s/\\\\/\\/g;
+			push @allow_rules, ['U', $_];
+		}
+	}
+}
+
+if ($op ne 'D') {
+	$new_type = git_value('cat-file','-t',$new);
+
+	if ($ref =~ m,^heads/,) {
+		deny "$ref must be a commit." unless $new_type eq 'commit';
+	} elsif ($ref =~ m,^tags/,) {
+		deny "$ref must be an annotated tag." unless $new_type eq 'tag';
+	}
+
+	check_committers (all_new_committers);
+	check_committers (all_new_taggers) if $new_type eq 'tag';
+}
+
+info "$this_user wants $op for $ref";
+foreach my $acl_entry (@allow_rules) {
+	my ($acl_ops, $acl_n) = @$acl_entry;
+	next unless $acl_ops =~ /^[CDRU]+$/; # Uhh.... shouldn't happen.
+	next unless $acl_n;
+	next unless $op =~ /^[$acl_ops]$/;
+	next unless match_string $acl_n, $ref;
+
+	# Don't test path rules on branch deletes.
+	#
+	grant "Allowed by: $acl_ops for $acl_n" if $op eq 'D';
+
+	# Aggregate matching path rules; allow if there aren't
+	# any matching this ref.
+	#
+	my %pr;
+	foreach my $p_entry (@path_rules) {
+		my ($p_ops, $p_n, $p_ref, $p_bst) = @$p_entry;
+		next unless $p_ref;
+		push @{$pr{$p_bst}}, $p_entry if match_string $p_ref, $ref;
+	}
+	grant "Allowed by: $acl_ops for $acl_n" unless %pr;
+
+	# Allow only if all changes against a single base are
+	# allowed by file path rules.
+	#
+	my @bad;
+	foreach my $p_bst (keys %pr) {
+		my $diff_ref = load_diff $p_bst;
+		deny "Cannot difference trees." unless ref $diff_ref;
+
+		my %fd = %$diff_ref;
+		foreach my $p_entry (@{$pr{$p_bst}}) {
+			my ($p_ops, $p_n, $p_ref, $p_bst) = @$p_entry;
+			next unless $p_ops =~ /^[AMD]+$/;
+			next unless $p_n;
+
+			foreach my $f_n (keys %fd) {
+				my $f_op = $fd{$f_n};
+				next unless $f_op;
+				next unless $f_op =~ /^[$p_ops]$/;
+				delete $fd{$f_n} if match_string $p_n, $f_n;
+			}
+			last unless %fd;
+		}
+
+		if (%fd) {
+			push @bad, [$p_bst, \%fd];
+		} else {
+			# All changes relative to $p_bst were allowed.
+			#
+			grant "Allowed by: $acl_ops for $acl_n diff $p_bst";
+		}
+	}
+
+	foreach my $bad_ref (@bad) {
+		my ($p_bst, $fd) = @$bad_ref;
+		print STDERR "\n";
+		print STDERR "Not allowed to make the following changes:\n";
+		print STDERR "(base: $p_bst)\n";
+		foreach my $f_n (sort keys %$fd) {
+			print STDERR "  $fd->{$f_n} $f_n\n";
+		}
+	}
+	deny "You are not permitted to $op $ref";
+}
+close A;
+deny "You are not permitted to $op $ref";