one reference for tru64 chgpt: expect uses function that calls chgpt

Toni L. Harbaugh-Blackford harbaugh at
Fri Aug 30 22:03:04 EST 2002

Here is one reference to the use of chgpt:

     Expect FAQ

     66.  Why does Expect work as root, but say "out of ptys" when run as myself? 
           Expect works fine as root, but when I run it as myself it says "out of
           ptys" (which I know isn't true).  Any ideas?
     Sounds like a misconfiguration problem on your system. For example, once I saw
     this on a Digital system where the system administrator had decided to remove
     setuid from all programs ("I heard that setuid is a security risk, right?"). On that
     particular system, Expect uses a system library function that internally
     calls an external program chgpt which exists solely for the purpose of managing
     ptys. Needless to say, it must be setuid.  Unfortunately, the library function
     doesn't do enough error checking, and there's no way for Expect to know that,
     so there's nothing I can do to give a better diagnostic explaining how your
     system is misconfigured.

But I don't remember the library call.  Anyone seen the expect code?

Toni Harbaugh-Blackford                     harbaugh at
AlphaServer 8400 System Administrator
SAIC/NCI Frederick Advanced Biomedical Computing Center

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