[lldb-dev] [Bug 18749] New: built-in pexpect.py produces ioctl sign-extension warnings on FreeBSD

bugzilla-daemon at llvm.org bugzilla-daemon at llvm.org
Wed Feb 5 17:25:20 PST 2014


http://llvm.org/bugs/show_bug.cgi?id=18749

            Bug ID: 18749
           Summary: built-in pexpect.py produces ioctl sign-extension
                    warnings on FreeBSD
           Product: lldb
           Version: unspecified
          Hardware: PC
                OS: FreeBSD
            Status: NEW
          Severity: normal
          Priority: P
         Component: All Bugs
          Assignee: lldb-dev at cs.uiuc.edu
          Reporter: emaste at freebsd.org
    Classification: Unclassified

LLDB includes a copy of pexpect, in test/pexpect-2.4/pexpect.py

It includes a hack to work around some buggy platforms:

        # Check for buggy platforms. Some Python versions on some platforms     
        # (notably OSF1 Alpha and RedHat 7.1) truncate the value for            
        # termios.TIOCSWINSZ. It is not clear why this happens.                 
        # These platforms don't seem to handle the signed int very well;        
        # yet other platforms like OpenBSD have a large negative value for      
        # TIOCSWINSZ and they don't have a truncate problem.                    
        # Newer versions of Linux have totally different values for TIOCSWINSZ. 
        # Note that this fix is a hack.                                         
        TIOCSWINSZ = getattr(termios, 'TIOCSWINSZ', -2146929561)               
        if TIOCSWINSZ == 2148037735L: # L is not required in Python >= 2.2.    
            TIOCSWINSZ = -2146929561 # Same bits, but with sign.               

-2146929561 == 0xffffffff80087467.  Passing this sign-extended value, instead
of the desired 0x80087467, produces a warning message in the system console on
FreeBSD:

Feb  5 17:19:11 feynman kernel: WARNING pid 11323 (python2.7): ioctl
sign-extension ioctl ffffffff80087467

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