That is generally the sort of thing TOCTTOU refers to. However, it is usually used in a security context. Security checks and decisions should generally be made in a single function where there is no ambiguity. In this case it, in order to avoid TOCTTOU issues you would need to invoke an EXECIO function that, when it fails, tells you why exactly why it failed, or give you sufficient program information to deduce why, without invoking some other check against the same thing.
Lennie -----Original Message----- From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Bob Bridges Sent: 22 August 2024 21:57 To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Simple Rexx question Wait, so was Gil just asking whether there's a "danger" of (for example) the DSN not being there when I run DSDD, but then coïncidentally having been catalogued 20 milliseconds later when I start to try to create it? I guess that's a function not of DSDD itself but of whatever routine uses it. --- Bob Bridges, robhbrid...@gmail.com, cell 336 382-7313 /* The cities are for money but the high-up hills are purely for the soul. -from _Galloway_ by Louis L'Amour */ -----Original Message----- From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Lennie Bradshaw Sent: Thursday, August 22, 2024 09:33 TOCTTOU Time Of Check To Time Of Use -----Original Message----- From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Bob Bridges Sent: 22 August 2024 14:29 I don't know what TOCTTOU is. -----Original Message----- From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Paul Gilmartin Sent: Wednesday, August 21, 2024 22:32 Does this have a TOCTTOU hazard? --- On Wed, 21 Aug 2024 21:04:34 -0400, Bob Bridges wrote: >I have two external REXX execs that I use frequently (depending on which one >you need): > >TEMPDD returns a DD name that is guaranteed not to be currently in use; it's >up to the caller to allocate it. I can specify a prefix; for example, if I >call TEMPDD with arg "XYZ" then it might return "XYZ12345" or "XYZ01". ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
