From 558349630c00f9d89ebb9236c3d3b807c27c428d Mon Sep 17 00:00:00 2001
From: Andreas Hrubak <ad132454@uucp.hu>
Date: Wed, 31 Jul 2024 10:45:39 +0200
Subject: [PATCH] add diagnostics mostly

---
 root-tools/noshellinject | 12 +++++++++++-
 tabdata/td-add-headers   |  2 +-
 tabdata/td-alter         |  2 +-
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/root-tools/noshellinject b/root-tools/noshellinject
index 3f44d74..292ad49 100755
--- a/root-tools/noshellinject
+++ b/root-tools/noshellinject
@@ -24,7 +24,8 @@ set -e
 
 # where to save (bind-mount) read shell executables from /bin
 real_shells_dir=/var/lib/notashell
-# may extend if the neglegent program calls something else as shell
+# may extend if the neglegent program calls something else as shell.
+# all are presumed to be in /bin.
 shellnames=(sh dash bash)
 
 propagtype()
@@ -51,6 +52,8 @@ bind_mount_symlink()
 
 if [ "$1" = --inner ]
 then
+	echo "$0: creating private bind-mount on $real_shells_dir to save real shells" >&2
+	
 	mkdir -p "$real_shells_dir"
 	# bind-mount this dir over itself to be able to make private mounts under it
 	mount --bind "$real_shells_dir" "$real_shells_dir"
@@ -64,9 +67,13 @@ then
 		mount --bind /bin/$shell "$real_shells_dir/real-$shell"
 	done
 	
+	echo "$0: umount $real_shells_dir from the parent namespace" >&2
 	# after sub-mounts are mounted, clean up the parent mount from the parent namespace
 	nsenter -t $PPID -m umount -l "$real_shells_dir"
 	
+
+	echo "$0: creating private bind-mount on /bin to intercept shells" >&2
+
 	# bind-mount this dir over itself to be able to make private mounts under it
 	bind_mount_symlink /bin /bin
 	mount --make-private /bin
@@ -77,6 +84,7 @@ then
 		bind_mount_symlink /usr/tool/notashell /bin/$shell
 	done
 	
+	echo "$0: umount /bin from the parent namespace" >&2
 	# after sub-mounts are mounted, clean up the parent mount from the parent namespace
 	nsenter -t $PPID -m umount -l /bin
 	
@@ -91,5 +99,7 @@ else
 		exit 1
 	fi
 	
+	echo "$0: creating new mount-namespace to intercept shell executions" >&2
+	
 	exec unshare --mount --propagation=shared -- "$0" --inner "$@"
 fi
diff --git a/tabdata/td-add-headers b/tabdata/td-add-headers
index ef72a85..926262b 100755
--- a/tabdata/td-add-headers
+++ b/tabdata/td-add-headers
@@ -36,7 +36,7 @@ Do not add more columns than specified in the command parameters.
 
 =head1 EXAMPLE
 
-who | tr-trans | td-add-headers USER TTY DATE TIME COMMENT
+ who | td-trans | td-add-headers USER TTY DATE TIME COMMENT
 
 =cut
 
diff --git a/tabdata/td-alter b/tabdata/td-alter
index 209e442..74cd550 100755
--- a/tabdata/td-alter
+++ b/tabdata/td-alter
@@ -31,7 +31,7 @@ IS_BIGFILE depends on previously defined TYPE field.
 
  ls -l | td-trans-ls | td-alter TYPE='substr MODE,0,1' IS_BIGFILE='SIZE>10000000 && TYPE ne "d" ? "yes" : "no"'
 
-Strip sub-seconds and timezone from DATETIME field.
+Strip sub-seconds and timezone from DATETIME field:
 
  TIME_STYLE=full-iso ls -l | td-trans-ls | td-alter DATETIME='s/\..*//; $_'
 
-- 
2.11.4.GIT