Programs Outside of OpenBSD


Time of Check before Time of Use is normally avoided in OpenBSD
source code.

CAVEATS
   access() and faccessat() should never be used for actual access control.
   Doing so can result in a time of check vs. time of use security hole.

Unfortunately software isn't always written to simply open what it needs and use it. 

      access
      stat
      readlink

glib functions expect stat() and access() to work all the way down.