[PATCH 4/9] lei: set PWD correctly for path expansion

[Eric Wong <e@80x24.org>]

While commit d1b9582872d1824f166a038dcf32b6ae8c6dc735
("lei: pass FD to CWD via cmsg, use fchdir on server")
ensured things work properly to get the daemon in the
right directory, it forgot to deal with places where
we expand relative paths based on the current working
directory.
---
 lib/PublicInbox/LEI.pm | 56 ++++++++++++++++++++++++++++--------------
 1 file changed, 37 insertions(+), 19 deletions(-)

diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index c017fd4e..0ce6a00b 100644
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -13,6 +13,7 @@ use parent qw(PublicInbox::DS PublicInbox::LeiExternal
 use Getopt::Long ();
 use Socket qw(AF_UNIX SOCK_SEQPACKET MSG_EOR pack_sockaddr_un);
 use Errno qw(EAGAIN EINTR ECONNREFUSED ENOENT ECONNRESET);
+use Cwd qw(getcwd);
 use POSIX ();
 use IO::Handle ();
 use Fcntl qw(SEEK_SET);
@@ -65,18 +66,37 @@ sub opt_dash ($$) {
 	($spec, '<>' => $cb, $GLP_PASS) # for Getopt::Long
 }
 
+sub rel2abs ($$) {
+	my ($self, $p) = @_;
+	return $p if index($p, '/') == 0; # already absolute
+	my $pwd = $self->{env}->{PWD};
+	if (defined $pwd) {
+		my $cwd = $self->{3} // getcwd() // die "getcwd(PWD=$pwd): $!";
+		if (my @st_pwd = stat($pwd)) {
+			my @st_cwd = stat($cwd) or die "stat($cwd): $!";
+			"@st_pwd[1,0]" eq "@st_cwd[1,0]" or
+				$self->{env}->{PWD} = $pwd = $cwd;
+		} else { # PWD was invalid
+			delete $self->{env}->{PWD};
+			undef $pwd;
+		}
+	}
+	$pwd //= $self->{env}->{PWD} = getcwd() // die "getcwd(PWD=$pwd): $!";
+	File::Spec->rel2abs($p, $pwd);
+}
+
 sub _store_path ($) {
-	my ($env) = @_;
-	File::Spec->rel2abs(($env->{XDG_DATA_HOME} //
-		($env->{HOME} // '/nonexistent').'/.local/share')
-		.'/lei/store', $env->{PWD});
+	my ($self) = @_;
+	rel2abs($self, ($self->{env}->{XDG_DATA_HOME} //
+		($self->{env}->{HOME} // '/nonexistent').'/.local/share')
+		.'/lei/store');
 }
 
 sub _config_path ($) {
-	my ($env) = @_;
-	File::Spec->rel2abs(($env->{XDG_CONFIG_HOME} //
-		($env->{HOME} // '/nonexistent').'/.config')
-		.'/lei/config', $env->{PWD});
+	my ($self) = @_;
+	rel2abs($self, ($self->{env}->{XDG_CONFIG_HOME} //
+		($self->{env}->{HOME} // '/nonexistent').'/.config')
+		.'/lei/config');
 }
 
 # TODO: generate shell completion + help using %CMD and %OPTDESC
@@ -295,7 +315,7 @@ sub atfork_prepare_wq {
 	my ($self, $wq) = @_;
 	my $tcafc = $wq->{-ipc_atfork_child_close} //= [ $listener // () ];
 	if (my $sock = $self->{sock}) {
-		push @$tcafc, @$self{qw(0 1 2)}, $sock;
+		push @$tcafc, @$self{qw(0 1 2 3)}, $sock;
 	}
 	if (my $pgr = $self->{pgr}) {
 		push @$tcafc, @$pgr[1,2];
@@ -345,7 +365,7 @@ sub atfork_parent_wq {
 		$ret->{dedupe} = $wq->deep_clone($dedupe);
 	}
 	$self->{env} = $env;
-	delete @$ret{qw(-lei_store cfg old_1 pgr lxs)}; # keep l2m
+	delete @$ret{qw(3 -lei_store cfg old_1 pgr lxs)}; # keep l2m
 	my @io = delete @$ret{0..2};
 	$io[3] = delete($ret->{sock}) // $io[2];
 	my $l2m = $ret->{l2m};
@@ -362,7 +382,7 @@ sub _help ($;$) {
 	my @info = @{$CMD{$cmd} // [ '...', '...' ]};
 	my @top = ($cmd, shift(@info) // ());
 	my $cmd_desc = shift(@info);
-	$cmd_desc = $cmd_desc->($self->{env}) if ref($cmd_desc) eq 'CODE';
+	$cmd_desc = $cmd_desc->($self) if ref($cmd_desc) eq 'CODE';
 	my @opt_desc;
 	my $lpad = 2;
 	for my $sw (grep { !ref } @info) { # ("prio=s", "z", $GLP_PASS)
@@ -520,7 +540,7 @@ sub dispatch {
 
 sub _lei_cfg ($;$) {
 	my ($self, $creat) = @_;
-	my $f = _config_path($self->{env});
+	my $f = _config_path($self);
 	my @st = stat($f);
 	my $cur_st = @st ? pack('dd', $st[10], $st[7]) : ''; # 10:ctime, 7:size
 	if (my $cfg = $PATH2CFG{$f}) { # reuse existing object in common case
@@ -550,8 +570,7 @@ sub _lei_store ($;$) {
 	$cfg->{-lei_store} //= do {
 		require PublicInbox::LeiStore;
 		my $dir = $cfg->{'leistore.dir'};
-		$dir //= _store_path($self->{env}) if $creat;
-		return unless $dir;
+		$dir //= $creat ? _store_path($self) : return;
 		PublicInbox::LeiStore->new($dir, { creat => $creat });
 	};
 }
@@ -587,9 +606,8 @@ sub lei_init {
 	my ($self, $dir) = @_;
 	my $cfg = _lei_cfg($self, 1);
 	my $cur = $cfg->{'leistore.dir'};
-	my $env = $self->{env};
-	$dir //= _store_path($env);
-	$dir = File::Spec->rel2abs($dir, $env->{PWD}); # PWD is symlink-aware
+	$dir //= _store_path($self);
+	$dir = rel2abs($self, $dir);
 	my @cur = stat($cur) if defined($cur);
 	$cur = File::Spec->canonpath($cur // $dir);
 	my @dir = stat($dir);
@@ -601,7 +619,7 @@ sub lei_init {
 		}
 
 		# some folks like symlinks and bind mounts :P
-		if (@dir && "$cur[0] $cur[1]" eq "$dir[0] $dir[1]") {
+		if (@dir && "@cur[1,0]" eq "@dir[1,0]") {
 			lei_config($self, 'leistore.dir', $dir);
 			_lei_store($self, 1)->done;
 			return qerr($self, "$exists (as $cur)");
@@ -771,7 +789,7 @@ sub accept_dispatch { # Listener {post_accept} callback
 	my ($argc, @argv) = split(/\0/, $buf, -1);
 	undef $buf;
 	my %env = map { split(/=/, $_, 2) } splice(@argv, $argc);
-	if (chdir(delete($self->{3}))) {
+	if (chdir($self->{3})) {
 		local %ENV = %env;
 		$self->{env} = \%env;
 		eval { dispatch($self, @argv) };