Yea, I was going to mention using TCBUSER is dangerous, since it's eyed by everybody lookin for an anchor, but I didn't think this particular point was relevant to my definition :)
David Logan -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Gerhard Postpischil Sent: Sunday, January 13, 2008 4:06 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: Rexx external assembler functions and reentrancy David Logan wrote: > In the examples cited previously, if you store the address using the > name/token callable services, another process can obtain that address using > the same utility. Another option was to store the address in the TCBUSER > field of the current TCB. This means that any program after that that is > being run under the same TCB can obtain that address by getting the value of > the TCBUSER field of the current TCB. The "user" in TCBUSER and CVTUSER would appear to be the installation, rather than the casual programmer, since both are store protected. One of my colleagues found this nifty CBT IEFACTRT that added I/O counts on the listing (object or load module form), and never noticed that it used TCBUSER. We lost billing data for a week! Since then I have found other installations that take advantage of the USER fields. And in Lindy's case getting privileged in a REXX subroutine is somewhat unlikely. Gerhard Postpischil Bradford, VT ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
