'ip netns exec' changes the current netns just before executing a child
process, and restores it after forking. This is needed if we're running
in batch or do_all mode.
Some cleanups must be done both in the parent and in the child: the
parent must restore the previous netns, while the child must reset any
VRF association.
Unfortunately, if do_all is set, the VRF are not reset in the child, and
the spawned processes are started with the wrong VRF context. This can
be triggered with this script:
# ip -b - <<-'EOF'
link add type vrf table 100
link set vrf0 up
link add type dummy
link set dummy0 vrf vrf0 up
netns add ns1
EOF
# ip -all -b - <<-'EOF'
vrf exec vrf0 true
netns exec setsid -f sleep 1h
EOF
# ip vrf pids vrf0
314 sleep
# ps 314
PID TTY STAT TIME COMMAND
314 ? Ss 0:00 sleep 1h
Refactor cmd_exec() and pass to it a function pointer which is called in
the child before the final exec. In the netns exec case the function just
resets the VRF and switches netns.
Doing it in the child is less error prone and safer, because the parent
environment is always kept unaltered.
After this refactor some utility functions became unused, so remove them.
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
903818fbf9