37.5. Trusted and Untrusted PL/Perl

Normally, PL/Perl is installed as a "trusted" programming language named plperl. In this setup, certain Perl operations are disabled to preserve security. In general, the operations that are restricted are those that interact with the environment. This includes file handle operations, require, and use (for external modules). There is no way to access internals of the database server process or to gain OS-level access with the permissions of the server process, as a C function can do. Thus, any unprivileged database user may be permitted to use this language.

Here is an example of a function that will not work because file system operations are not allowed for security reasons:

CREATE FUNCTION badfunc() RETURNS integer AS $$
    open(TEMP, ">/tmp/badfile");
    print TEMP "Gotcha!\n";
    return 1;
$$ LANGUAGE plperl;


I believe the code snippet should look like this for it to work correctly:



CREATE FUNCTION badfunc() RETURNS integer AS $$
    open(TEMP, ">/tmp/badfile");
    print TEMP "Gotcha!\n";
    close(TEMP);
    return 1;
$$ LANGUAGE plperl;