popen: exec.c and file.c

Hey, I've noticed that we use php_Exec for the following php functions: exec, system, passthru and a couple of functions in vpopmail. But we bypass php_Exec for popen, shell_exec (backticks). The difference between using php_Exec and not using it, apart from the various modes of operation in php_Exec, is that php_Exec does some additional sanity/security checks in safe_mode. This difference only really affects the PHP popen() function. Should it be doing the same checks as php_Exec? The reason that I am looking at this stuff is that I am now toying with the idea of a "process stream" that will effectively be the same as a popen()ed FILE * but will allow both reading and writing to/from the process. It would be implemented by manually creating a pipe for stdin and another for stdout and setting them up for the exec'd process. Under windows it's a slightly different story but I do have some code laying around that can be used for this purpose. Comments anyone? --Wez.