Dh_Lib,dh_installman: Reopen stdin for reading in doit/man(1)-check

This make debhelper work when run under nohup(1), which opens stdin
for writing.  Trivial to test with:

  dpkg-buildpackage [...] 0>/dev/null

(Once you know that you are looking for it).

Signed-off-by: Niels Thykier <niels@thykier.net>

3 files changed, 13 insertions, 1 deletions

diff --git a/debian/changelog b/debian/changelog
index 39517595..f69a7edc 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,14 @@
+debhelper (11.5.4) UNRELEASED; urgency=medium
+
+  * Dh_Lib.pm: Reopen stdin to read from /dev/null in doit (and its sibling
+    functions) to prevent issues when stdin is open in write-only mode
+    (which is what nohup(1) does).  Thanks to Julian Gilbey for reporting
+    the issue and providing a sample patch for it as well.
+    (Closes: #913663)
+  * dh_installman: Ditto.
+
+ -- Niels Thykier <niels@thykier.net>  Tue, 13 Nov 2018 20:30:49 +0000
+
 debhelper (11.5.3) unstable; urgency=medium
 
   [ Helmut Grohne ]
diff --git a/dh_installman b/dh_installman
index a41d9c8e..96d6c7a5 100755
--- a/dh_installman
+++ b/dh_installman
@@ -272,7 +272,7 @@ on_items_in_parallel(\@all_packages, sub {
 });
 
 # Now utf-8 conversion.
-if (defined `man --version`) {
+if (defined `man --version </dev/null`) {
 	my (@manpages_to_reencode, @issues);
 	for my $package (@{$dh{DOPACKAGES}}) {
 		next if is_udeb($package);
diff --git a/lib/Debian/Debhelper/Dh_Lib.pm b/lib/Debian/Debhelper/Dh_Lib.pm
index aa7448bc..482e758e 100644
--- a/lib/Debian/Debhelper/Dh_Lib.pm
+++ b/lib/Debian/Debhelper/Dh_Lib.pm
@@ -456,6 +456,7 @@ sub _doit {
 					chdir($dir) or error("chdir(\"${dir}\) failed: $!");
 				}
 			}
+			open(STDIN, '<', '/dev/null') or error("redirect STDIN failed: $!");
 			if (defined(my $output = $options->{stdout})) {
 				open(STDOUT, '>', $output) or error("redirect STDOUT failed: $!");
 			}