Re: Problem Building Cygwin PostgreSQL

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: Jason(dot)Tishler(at)dothill(dot)com
Hazlet, NJ 07730 USA WWW: http://www.dothill.com

Looks like this is fixed in current sources.

> 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: Jason(dot)Tishler(at)dothill(dot)com
> Hazlet, NJ 07730 USA WWW: http://www.dothill.com
>

--
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