Subject: Re: Problem Building Cygwin PostgreSQL
From: Jason Tishler <[email-masked]>
To: Earnie Boyd <[email-masked]>
Cc: "Dr. Volker Zell" <[email-masked]>, Cygwin <[email-masked]>, [email-masked]
Date: Fri, 22 Sep 2000 15:50:51 -0400

Earnie,

On Fri, Sep 22, 2000 at 11:01:25AM -0700, Earnie Boyd wrote:
> Hmm...  This appears that it would potentially cause a memory leak.  What
> happens if instead of this patch you initialize the pointer to NULL?

I guess that I should have giving more context:

    void
    usage(void)
    {
        ...
        user = getenv("USER");
        if (!user)
        {
    #ifndef WIN32
            pw = getpwuid(geteuid());
            if (pw)
                user = pw->pw_name;
            ...
    #else
            user = "?";
    #endif
        }
        ...
    #if !defined(WIN32) && !defined(__CYGWIN__)
        if (pw)
            free(pw);
    #endif
    }

The relevant Cygwin source (i.e., src/winsup/cygwin/passwd.cc) and the
getpwuid() man page (from Solaris):

    The  functions  getpwnam(),  getpwuid(),   getpwent(),   and
    fgetpwent() use *static* storage that is re-used in each call,
    making these routines unsafe for use in multithreaded appli-
    cations.

seemed to indicate that free-ing the return value from getpwuid() was a
bad idea.  Can someone confirm or refute this supposition?

Thanks,
Jason

-- 
Jason Tishler
Director, Software Engineering       Phone: +1 (732) 264-8770 x235
Dot Hill Systems Corporation         Fax:   +1 (732) 264-8798
82 Bethany Road, Suite 7             Email: [email-masked]
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