Getting absolute path with "ls" command
ls by default list everything supplied via argument. From man ls:


  -d, --directory
               list directories themselves, not their contents
  
  -l     use a long listing format


So you can simly supply everything inside your targer directory, and give the option -d.

[adb shell] [su -c] ls -dl /etc/*
^ optional, depending on your shell environment


Which gives

rwxr--r-- 1 root root 1024 Jun 4 22:32 /etc/hosts
...
(and a lone list)