From 353cd4756993ed1358bdc3c797762ac5595f3bf5 Mon Sep 17 00:00:00 2001
From: Donald Buczek <buczek@molgen.mpg.de>
Date: Tue, 6 Dec 2016 09:00:48 +0100
Subject: [PATCH 1/3] pdist: Support symlink mtimes in index

We want to maintain the mtime of symlinks in the slaves. As a first step
we need to pass that information to the slave. So we expand the external
format of an index record to include that time. The exporter and
importer functions are updated.
---
 pdist/pdist | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pdist/pdist b/pdist/pdist
index 9372193..b0ac949 100755
--- a/pdist/pdist
+++ b/pdist/pdist
@@ -86,7 +86,7 @@ sub export_index
 			$type eq 'B' || $type eq 'C' ? $self->rdev :
 			'-'
 		),
-		$type eq 'F'||$type eq 'D' ? $self->mtime : '-',
+		$type eq 'F' || $type eq 'D' || $type eq 'L' ? $self->mtime : '-',
 	);
 }
 
@@ -103,7 +103,7 @@ sub import_index
 		$F[3],$F[4],	# uid,gid
 		($type eq 'B' || $type eq 'C' ? $F[5] : 0),	# rdev
 		($type eq 'F' ? $F[5] : 0 ),			# size
-		($type eq 'F'||$type eq 'D' ? $F[6] : 0 ),	# mtime
+		($type eq 'F'|| $type eq 'D' || $type eq 'L' ? $F[6] : 0 ),	# mtime
 		($type eq 'L' ? fn_unescape($F[5]) : ''),	# target
 
 	],

From 7b981122e68c0307cf13469f5b9a77bc72ed7b6a Mon Sep 17 00:00:00 2001
From: Donald Buczek <buczek@molgen.mpg.de>
Date: Tue, 6 Dec 2016 09:03:26 +0100
Subject: [PATCH 2/3] pdist: Add fileop_lmtime

Add a function to change the mtime of a symlink. There is no perl
function available for that, but newer kernels have a syscall. Syscall
number and arguments depend on architecture.
---
 pdist/pdist | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/pdist/pdist b/pdist/pdist
index b0ac949..a1534e0 100755
--- a/pdist/pdist
+++ b/pdist/pdist
@@ -306,7 +306,7 @@ sub index_file_sort { return sort @_; }
 
 #---------------------------- lchown / mknod
 
-our ($machine,$SYS_lchown,$SYS_mknod);
+our ($machine,$SYS_lchown,$SYS_mknod,$lmtime_sub);
 chomp($machine=`uname -m`);
 if ($machine eq 'i686') {
 	$SYS_lchown=198;		# __NR_lchown32  in /usr/include/asm/unistd.h
@@ -325,6 +325,24 @@ if ($machine eq 'i686') {
 	warn "unknown machine type $machine: named pipes,character and block devices can't be created\n";
 }
 
+if ($machine eq 'x86_64') {
+	our $SYS_utimensat=280;			# /usr/include/asm/unistd_64.h
+	our $AT_FDCWD=-100;			# /usr/include/fcntl.h
+	our $UTIME_OMIT=(1<<30)-2;		# /usr/include/bits/stat.h
+	our $AT_SYMLINK_NOFOLLOW=0x100;		# /usr/include/fcntl.h
+
+	$lmtime_sub=sub {
+		my ($path,$mtime)=@_;
+		my $tsa=pack 'qqqq',0,$UTIME_OMIT,$mtime,0;
+		syscall($SYS_utimensat,$AT_FDCWD,$path,$tsa,$AT_SYMLINK_NOFOLLOW) and die "$path: $!\n";
+	}
+} else {
+	$lmtime_sub=sub {
+		my ($path,$mtime)=@_;
+		warn "$path: don't known how to change symlink mtime on target architecture\n";
+	}
+}
+
 sub lchown
 {
 	my ($uid,$gid,$path)=@_;
@@ -453,6 +471,13 @@ sub fileop_ln_or_cp
 	}
 }
 
+sub fileop_lmtime {
+	my ($mtime,$path)=@_;
+	$fileop_debug and warn "lmtime $mtime $path\n";
+	$fileop_noop and return;
+	$lmtime_sub->($path,$mtime);
+}
+
 #--------------------------------------------
 
 sub index_wanted

From 43687f3edc379212ca8b8e0e03c2792a787b10b1 Mon Sep 17 00:00:00 2001
From: Donald Buczek <buczek@molgen.mpg.de>
Date: Tue, 6 Dec 2016 09:05:26 +0100
Subject: [PATCH 3/3] pdist: Maintain symlink mtime on client

Create symlinks with the mtime from master or fix the mtime on existing
symlinks if needed.
---
 pdist/pdist | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/pdist/pdist b/pdist/pdist
index a1534e0..9318b3f 100755
--- a/pdist/pdist
+++ b/pdist/pdist
@@ -748,11 +748,16 @@ sub prog_update
 					$quiet or warn "ln -s ".$st_want->target." $filename\n";
 					fileop_symlink($st_want->target,$filename);
 					fileop_lchown($st_want->uid,$st_want->gid,$filename);
+					fileop_lmtime($st_want->mtime,$filename);
 				} else {
 					if ($st_is->uid != $st_want->uid || $st_is->gid != $st_want->gid) {
 						$quiet or warn "lchown ".$st_want->uid.':'.$st_want->gid." $filename\n";
 						fileop_lchown($st_want->uid,$st_want->gid,$filename);
 					}
+					if ($st_is->mtime != $st_want->mtime) {
+						$quiet or warn "set mtime of $filename\n";
+						fileop_lmtime($st_want->mtime,$filename);
+					}
 				}
 			} elsif ($st_want->type eq 'P') {
 				if (!$st_is || $st_is->type ne 'P') {