使用RETURN陷阱进行bash清理并立即重置处理程序

Question

Is there a way to disable a trap within the trap handler?

I'd like to simplify some code by using the RETURN trap. my_func will return the value of my_command. The tmpfile will be cleaned up as my_func returns. This technique would allow me to avoid assigning a temp var to hold $? from my_func while I do cleanup.

However, I'm unable to reset the trap handler within the handler and cleanup is now invoked after every function return.

Ultimately what I really want to do is cleanup after my_command is invoked but still have it as the last command so the return value is implicit. Any suggested alternatives would be appreciated.

cleanup() { # generic cleanup w/ reset
   "$@"
   trap - RETURN
}

my_func() {
   local -r tmpfile="/tmp/tmpfile"
   trap "cleanup rm ${tmpfile}" RETURN
   my_command -f ${tmpfile}
}

caller() {
   if my_func ; then
      do_success_ops
   fi
}

Answer 1

I always use this pattern:

trap 'rm -rf "$workspace"' EXIT
workspace="$(mktemp --directory)" # Or -d
# Use $workspace

This has several nice features:

1. The trap is set up before creating the directory, so there is no race condition.
2. Creating a directory means I shouldn't need any more mktemp calls in the script, because I can just put everything in that directory.
3. Creating a directory rather than a file gives a better security baseline, because it's common that everyone can see what's directly in /tmp , but a new directory will be owned by you and will be created "u+rwx, minus umask restrictions" (from man mktemp ).

If you want to clean up earlier I would recommend just doing it explicitly. Your solution has two unnecessary levels of indirection: the trap and the passing of arguments to be run.