selftest/ns/mk_nsenter.sh

   1 #!/bin/sh
   2 #
   3 # Helper script. If you want a 2nd shell that communicates with the testenv DC
   4 # you can use the nsenter command to change the namespace you're in. However,
   5 # this command is a bit unwieldly and changes depending on the testenv PID.
   6 # We can generate a helper script on the fly that abstracts all this
   7 # complexity, allowing you to use the same, simple command to change the
   8 # namespace that you're in, e.g.
   9 #   st/ad_dc/nsenter.sh
  10
  11 pid=$1
  12 exports_file=$2
  13
  14 # The basic command to enter the testenv's network namespace.
  15 # We enter the user namespace as well (as ourself, which is really the root
  16 # user for the namespace), otherwise we need sudo to make this work.
  17 nsenter_cmd="nsenter -t $pid --net --user --preserve-credentials"
  18
  19 # By default, the nsenter command will just start a new shell in the namespace.
  20 # we use a wrapper helper script, which first loads all the environment
  21 # variables that are usually defined in selftest (and prints some basic help).
  22 helper_script="$(dirname $0)/nsenter-helper.sh $exports_file"
  23
  24 # generate the dynamic script
  25 dyn_script="$(dirname $2)/nsenter.sh"
  26 echo "#!/bin/sh" > $dyn_script
  27 echo "$nsenter_cmd $helper_script" >> $dyn_script
  28 chmod 755 $dyn_script
  29
  30 # return the script we created
  31 echo "$dyn_script"
  32