NAME
    Unix::Pledge - restrict system operations

SYNOPSIS
      use Unix::Pledge;

      # ...
      # Program initializtion, open files, drop privileges, fork, etc
      # ...

      # Now that we're initialized, limit our process to reading our .profile 
      pledge("stdio rpath", ["/home/$ENV{USER}/.profile"]);

      # Reading user's .profile works as expected
      open(my $fd, "<", "/home/$ENV{USER}/.profile");
      while(<$fd>) {
        print $_;
      }
 
      # Trying to open outside whitelisted path fails with file not found
      open($fd, "<", "/etc/passwd") or warn $!;

      # Trying to write will cause SIGABRT
      open($fd, ">", "/home/$ENV{USER}/.profile");

      # Abort trap (core dumped)

DESCRIPTION
    The current process is forced into a restricted-service operating mode.
    A few subsets are available, roughly described as computation, memory
    management, read-write operations on file descriptors, opening of files,
    networking. In general, these modes were selected by studying the
    operation of many programs using libc and other such interfaces, and
    setting promises or paths.

    Requires that the kernel supports the pledge(2) syscall, which as of
    this writing is only available in OpenBSD.

    The pledge function takes two parameters: "promises" and "whitepaths".

    "Promises" is a space delimited string of modes which the process is
    promising that it will stick to from here on out. "Whitepaths" is an
    optional array ref parameter that is useful to further limit the process
    to operate under specific paths only. Paths that are not under the
    whitepath will return ENOENT if you attempt to access them.

    Process violations of the previously "pledged" modes will result in your
    processing being forcibly terminated via SIGABRT. In this way pledge
    serves as a capabilities framework like capsicum, systrace, AppArmor,
    etc. The difference is that pledge aims to be very easy to use for the
    typical developer to sandbox their process.

    Note that restrictions are one way only: you can only increase the
    restrictions on your process, not relax them.

  ERRORS
    Unix::Pledge will croak on any errors.

  EXPORT
    The "pledge" function is exported by default.

SEE ALSO
    For detailed information on pledge, its parameters and errors, please
    see the OpenBSD pledge(2) man page
    <http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man2/pledge.2?qu
    ery=pledge>.

    Github repo <https://github.com/rfarr/Unix-Pledge>

AUTHOR
    Richard Farr "<richard@nxbit.io>"

COPYRIGHT AND LICENSE
    Copyright (C) 2015 by Richard Farr

    This module is licensed under the same terms as perl itself.

