one example of intercepting/renaming syscalls is <ast.h> already, and for a
while,
translates all foo() syscalls to foo64() where foo64() is avaliable
On Wed, 29 Aug 2012 09:10:34 -0400 Glenn Fowler wrote:
> we're going to take some research leeway and investigate the implications of
> {a}
> we're not strangers to doing stuff like that (3d(1))
> and we're not strangers to having research prove us wrong
> On Wed, 29 Aug 2012 14:49:33 +0200 Cedric Blancher wrote:
> > On 29 August 2012 13:54, Roland Mainz <roland.ma...@nrubsig.org> wrote:
> > > [Forwarding since AT&T's spam filter is on drugs... ;-(( ]
> > > ---------- Forwarded message ----------
> > > From: ÏÌØÇÁ ËÒÙÖÁÎÏ×ÓËÁÑ <olga.kryzhanov...@gmail.com>
> > > Date: Wed, Aug 29, 2012 at 1:20 PM
> > > Subject: Re: [ast-developers] Fwd: Per thread open(), stat(), rename()
> > > and so on, and *at() API
> > > To: Lionel Cons <lionelcons1...@googlemail.com>
> > > Cc: Roland Mainz <roland.ma...@nrubsig.org>,
> > > ast-developers@research.att.com
> > >
> > >
> > > Lionel, there are 2 purposes:
> > >
> > > 1. Allow that ksh93/libshell can be embedded in other applications
> > > (Roland calls this 'back end usage', i.e. the user is not aware that
> > > he is interacting with a shell, and neither do any other apis know
> > > that, or at least should not have to know about that), with out
> > > interfering the calling application by changing the current working
> > > directory.
> > > 2. Allow that ksh93/libshell and the libast api can have a per thread
> > > current working directory.
> > >
> > > There are 2 proposals how to accomplish that:
> > > a) Add wrapper functions for open(), stat(), lstat(), chdir(),
> > > fchdir(), access(), eaccess(), rename() and so on, and redirect them
> > > to their *at() counterparts, with dirfd set to the current threads cwd
> > > fd.
> > >
> > > or
> > >
> > > b) Add wrapper cpp macros which redirect open(), stat(), lstat(),
> > > chdir(), fchdir(), access(), eaccess(), rename() and so on to their
> > > *at() counterparts, but define an extra macro which is AT_FDCWD for
> > > non threaded applications, and calls a function to obtain the current
> > > threads working directory fd for the current thread, but allows to
> > > override this macro on a per source file basis, so that applications
> > > like libshell, who maintain their own cwd directory fd, can use that.
> > >
> > > David and Glenn seems to prefer {a}, while I and Roland prefer {b},
> > > because {b} will allow an application to work as back end api without
> > > interfering with the global cwd or any other, may be libast based apis
> > > cwd. This includes nested usage of libshell, like for system() or
> > > wordexp().
> > I'd prefer option {b}, too. Strongly (sorry David and Glenn :)).
> > It sounds like the more sane and flexible way to do this. The big road
> > block is that you have to find a solution for old platforms which do
> > not have openat() and friends, or EOS (end-of-support) them (I'd
> > support that if no platform younger than four years lacks openat() and
> > friends).
> > Ced
> > --
> > Cedric Blancher <cedric.blanc...@googlemail.com>
> > Institute Pasteur
> > _______________________________________________
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> > ast-developers@research.att.com
> > https://mailman.research.att.com/mailman/listinfo/ast-developers
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