Re: UPDATED UnixWare Threads Patch.

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Larry Rosenman <ler(at)lerctr(dot)org>
Cc: pgsql-patches(at)postgresql(dot)org
Subject: Re: UPDATED UnixWare Threads Patch.
Date: 2003-08-14 21:13:56
Message-ID: 200308142113.h7ELDun08636@candle.pha.pa.us
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Sorry, patch attached and applied. I also added "SUPPORTS_THREADS=yes",
which was needed.

---------------------------------------------------------------------------

Larry Rosenman wrote:
> what about the pieces of src/port/unixware to allow the threads stuff?
>
>
>
> --On Thursday, August 14, 2003 01:25:48 -0400 Bruce Momjian
> <pgman(at)candle(dot)pha(dot)pa(dot)us> wrote:
>
> >
> > OK, I have applied the attached patch.
> >
> > Here is the comment I have added to the thread.c file:
> >
> > /*
> > * Threading sometimes requires specially-named versions of functions
> > * that return data in static buffers, like strerror_r() instead of
> > * strerror(). Other operating systems use pthread_setspecific()
> > * and pthread_getspecific() internally to allow standard library
> > * functions to return static data to threaded applications.
> > *
> > * Additional confusion exists because many operating systems that
> > * use pthread_setspecific/pthread_getspecific() also have *_r versions
> > * of standard library functions for compatibility with operating
> > systems * that require them. However, internally, these *_r
> > functions merely * call the thread-safe standard library functions.
> > *
> > * For example, BSD/OS 4.3 uses Bind 8.2.3 for getpwuid(). Internally,
> > * getpwuid() calls pthread_setspecific/pthread_getspecific() to return
> > * static data to the caller in a thread-safe manner. However, BSD/OS
> > * also has getpwuid_r(), which merely calls getpwuid() and shifts
> > * around the arguments to match the getpwuid_r() function declaration.
> > * Therefore, while BSD/OS has getpwuid_r(), it isn't required. It
> > also * doesn't have strerror_r(), so we can't fall back to only using
> > *_r * functions for threaded programs.
> > *
> > * The current setup is to assume either all standard functions are
> > * thread-safe (NEED_REENTRANT_FUNC_NAMES=no), or the operating system
> > * requires reentrant function names (NEED_REENTRANT_FUNC_NAMES=yes).
> > */
> >
> > As an additional data point, here is a README comment from Bind 8.2.3:
> >
> > Thread Safety:
> >
> > It is possible for a thread safe program to be altered to call
> > the underlying interface (rather than the standard getXbyY() stubs) and
> > get some reentrance capabilities. Note that the underlying libraries
> > (which we call) are not all thread-safe, for example, the YP and DNS
> > resolvers. A lot more work will need to be done before we have full
> > thread safety. But we believe that the native API for this system does
> > not impose any reentrancy problems. We don't use global or static
> > variables anywhere except in the getXbyY() stubs.
> >
> > Here is Bind's gethostbyname_r:
> >
> > HOST_R_RETURN
> > gethostbyname_r(const char *name, struct hostent *hptr, HOST_R_ARGS) {
> > struct hostent *he = gethostbyname(name);
> >
> > HOST_R_ERRNO;
> >
> > if (he == NULL)
> > return (HOST_R_BAD);
> >
> > return (copy_hostent(he, hptr, HOST_R_COPY));
> > }
> >
> > As you can see, it merely calls gethostbyname() and adjusts to return
> > the proper values.
> >
> > I removed the pre-POSIX getpwuid_r function call and added the POSIX
> > one. If we need the pre-POSIX one, we can add it with a configure
> > test, but I would rather find out if someone needs it first. The
> > original thread patch that was posted had only the pre-POSIX version of
> > the function, and I am not sure why the didn't include the POSIX one
> > too, or use that instead of the pre-POSIX one.
> >
> > There are also a few stylistic function declaration cleanups.
> >
> > The unixware optimizer changes have already been applied.
> >
> >
> > -------------------------------------------------------------------------
> > --
> >
> > Larry Rosenman wrote:
> >>
> >>
> >> --On Friday, August 08, 2003 18:56:45 -0500 Larry Rosenman
> >> <ler(at)lerctr(dot)org> wrote:
> >>
> >> >
> >> >
> >> > Here is the updated UnixWare threads patch. I need some help to set
> >> > the HAVE_POSIX_GETPWUID_R define from configure, but this will suffice
> >> > for now.
> >> >
> >> > This also includes my recommendation for the Compiler Bug issue.
> >> >
> >> > Please Apply, and if one of the configure guru's can help here, I'd be
> >> > most appreciative.
> >> Grr. I'm an idiot, the following is a CORRECTED version, basically
> >> s/#elsif/#elif/
> >>
> >> Index: src/port/thread.c
> >> ===================================================================
> >> RCS file: /projects/cvsroot/pgsql-server/src/port/thread.c,v
> >> retrieving revision 1.2
> >> diff -u -r1.2 thread.c
> >> --- src/port/thread.c 8 Aug 2003 03:09:56 -0000 1.2
> >> +++ src/port/thread.c 9 Aug 2003 00:47:00 -0000
> >> @@ -40,13 +40,18 @@
> >> pqGetpwuid(uid_t uid, struct passwd * resultbuf, char *buffer,
> >> size_t buflen, struct passwd ** result)
> >> {
> >> -#if defined(USE_THREADS) && defined(HAVE_GETPWUID_R)
> >> +#if defined(USE_THREADS) && defined(HAVE_GETPWUID_R) &&
> >> !defined(HAVE_POSIX_GETPWUID_R)
> >>
> >> /*
> >> * broken (well early POSIX draft) getpwuid_r() which returns 'struct
> >> * passwd *'
> >> */
> >> *result = getpwuid_r(uid, resultbuf, buffer, buflen);
> >> +#elif defined(USE_THREADS) && defined(HAVE_GETPWUID_R) &&
> >> defined(HAVE_POSIX_GETPWUID_R)
> >> + /*
> >> + * SUSv2/POSIX getpwuid_r
> >> + */
> >> + return getpwuid_r(uid, resultbuf, buffer, buflen, result);
> >> # else
> >> /* no getpwuid_r() available, just use getpwuid() */
> >> *result = getpwuid(uid);
> >> Index: src/template/unixware
> >> ===================================================================
> >> RCS file: /projects/cvsroot/pgsql-server/src/template/unixware,v
> >> retrieving revision 1.11
> >> diff -u -r1.11 unixware
> >> --- src/template/unixware 4 Sep 2002 22:54:18 -0000 1.11
> >> +++ src/template/unixware 9 Aug 2003 00:47:00 -0000
> >> @@ -1,5 +1,13 @@
> >> +SUPPORTS_THREADS=yes
> >> if test "$GCC" = yes; then
> >> - CFLAGS=-O2
> >> + CFLAGS="-O2 -DHAVE_POSIX_GETPWUID_R"
> >> + THREAD_CFLAGS="-pthread -D_REENTRANT"
> >> + NEED_REENTRANT_FUNC_NAMES=yes
> >> else
> >> - CFLAGS='-O -K inline'
> >> +# the -Kno_host is temporary for a bug in the compiler. See -hackers
> >> +# discussion on 7-8/Aug/2003.
> >> +# when the 7.1.3UP3 or later compiler is out, we can do a version check.
> >> + CFLAGS='-O -Kinline,no_host -DHAVE_POSIX_GETPWUID_R'
> >> + THREAD_CFLAGS="-D_REENTRANT -K pthread -DHAVE_POSIX_GETPWUID_R"
> >> + NEED_REENTRANT_FUNC_NAMES=yes
> >> fi
> >>
> >> --
> >> Larry Rosenman http://www.lerctr.org/~ler
> >> Phone: +1 972-414-9812 E-Mail: ler(at)lerctr(dot)org
> >> US Mail: 1905 Steamboat Springs Drive, Garland, TX 75044-6749
> >
> > [ Attachment, skipping... ]
> >
> >>
> >> ---------------------------(end of broadcast)---------------------------
> >> TIP 4: Don't 'kill -9' the postmaster
>
>
>
> --
> Larry Rosenman http://www.lerctr.org/~ler
> Phone: +1 972-414-9812 E-Mail: ler(at)lerctr(dot)org
> US Mail: 1905 Steamboat Springs Drive, Garland, TX 75044-6749
>

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073

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