In order to run Windows commands via PHP functions such as
open_proc(), apparently one has to grant read/execute permissions to the account under which IIS is running (usually IUSR_<servername>) on
C:\WINDOWS\System32\cmd.exe. Be sure to do this for web apps that rely on external commands.
This of course took me an eternity to figure out. I was only able to piece together WebSVN‘s bizarre Windows mis-behavior after scouring through the remnants of forum posts limboed in Google cache. PHP.net of course has no proper details on this, though I do now better understand what
proc_open‘s obscure and undocumented
bypass_shell parameter might be about.
Ah yes, PHP on Windows. Obscure and irritating.
Kind of like me. Not that that makes it any better.