What happened to _RESMGR_FLAG_EXCL, why was it removed?
And whats the correct workaround to ensure a no-race-condition
exclusive resmgr_attach?
Thanks in advance!
Cheers,
-RK
–
Robert Krten, PARSE Software Devices +1 613 599 8316.
Realtime Systems Architecture, Books, Video-based and Instructor-led
Training and Consulting at www.parse.com.
Email my initials at parse dot com.
David Gibbs <dagibbs@qnx.com> wrote:
Robert Krten <> nospam83@parse.com> > wrote:
What happened to _RESMGR_FLAG_EXCL, why was it removed?
And whats the correct workaround to ensure a no-race-condition
exclusive resmgr_attach?
Um…try a name_attach() first…whoever win’s the name_attach()
does the resmgr_attach()? >
Thanks, I’ll give that a try – any insight as to why it was
removed? It just seems so, oh, I don’t know, USEFUL!
Cheers,
-RK
-David
QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.
–
Robert Krten, PARSE Software Devices +1 613 599 8316.
Realtime Systems Architecture, Books, Video-based and Instructor-led
Training and Consulting at www.parse.com.
Email my initials at parse dot com.
Robert Krten <nospam83@parse.com> wrote:
What happened to _RESMGR_FLAG_EXCL, why was it removed?
And whats the correct workaround to ensure a no-race-condition
exclusive resmgr_attach?
Um…try a name_attach() first…whoever win’s the name_attach()
does the resmgr_attach()?
-David
QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.
Robert Krten <nospam83@parse.com> wrote:
David Gibbs <> dagibbs@qnx.com> > wrote:
Robert Krten <> nospam83@parse.com> > wrote:
What happened to _RESMGR_FLAG_EXCL, why was it removed?
And whats the correct workaround to ensure a no-race-condition
exclusive resmgr_attach?
Um…try a name_attach() first…whoever win’s the name_attach()
does the resmgr_attach()? >
Thanks, I’ll give that a try – any insight as to why it was
removed? It just seems so, oh, I don’t know, USEFUL! >
I have no idea. I don’t actually remember it being around. It is
not documented in my Neutrino v2.0 printed docs (1999), so it hasn’t
been around for quite a while.
-David
QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.
David Gibbs <dagibbs@qnx.com> wrote:
Robert Krten <> nospam83@parse.com> > wrote:
David Gibbs <> dagibbs@qnx.com> > wrote:
Robert Krten <> nospam83@parse.com> > wrote:
What happened to _RESMGR_FLAG_EXCL, why was it removed?
And whats the correct workaround to ensure a no-race-condition
exclusive resmgr_attach?
Um…try a name_attach() first…whoever win’s the name_attach()
does the resmgr_attach()? >
Thanks, I’ll give that a try – any insight as to why it was
removed? It just seems so, oh, I don’t know, USEFUL! >
I have no idea. I don’t actually remember it being around. It is
not documented in my Neutrino v2.0 printed docs (1999), so it hasn’t
been around for quite a while.
Huh. You’re right I seem to recall it being there around
Neutrino 1.00 – and now it lives in the resmgr_compat.h module
as a #define 0.
Oh well…
Thanks,
-RK
-David
QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.
–
Robert Krten, PARSE Software Devices +1 613 599 8316.
Realtime Systems Architecture, Books, Video-based and Instructor-led
Training and Consulting at www.parse.com.
Email my initials at parse dot com.
Kris Warkentin <kewarken@qnx.com> wrote:
“Robert Krten” <> nospam83@parse.com> > wrote in message
news:avvfo2$ad9$> 1@inn.qnx.com> …
I have no idea. I don’t actually remember it being around. It is
not documented in my Neutrino v2.0 printed docs (1999), so it hasn’t
been around for quite a while.
Huh. You’re right > > I seem to recall it being there around
Neutrino 1.00 – and now it lives in the resmgr_compat.h module
as a #define 0.
Time for an updated 2nd edition of you book I guess.
Hah! It’s not in my book – I think someone caught that already.
It’s just stuck in my brain
Cheers,
-RK
\
Robert Krten, PARSE Software Devices +1 613 599 8316.
Realtime Systems Architecture, Books, Video-based and Instructor-led
Training and Consulting at www.parse.com.
Email my initials at parse dot com.
“Robert Krten” <nospam83@parse.com> wrote in message
news:avvfo2$ad9$1@inn.qnx.com…
I have no idea. I don’t actually remember it being around. It is
not documented in my Neutrino v2.0 printed docs (1999), so it hasn’t
been around for quite a while.
Huh. You’re right > > I seem to recall it being there around
Neutrino 1.00 – and now it lives in the resmgr_compat.h module
as a #define 0.
Time for an updated 2nd edition of you book I guess.
Kris
Hi David could you just give a little explanation about this trick?
Thanks,
Alain.
David Gibbs a écrit:
Robert Krten <> nospam83@parse.com> > wrote:
What happened to _RESMGR_FLAG_EXCL, why was it removed?
And whats the correct workaround to ensure a no-race-condition
exclusive resmgr_attach?
Um…try a name_attach() first…whoever win’s the name_attach()
does the resmgr_attach()? >
-David
David, could you give us some detail on how that works? I thought
name_attach() just called resmgr_attach. Also, the docs don’t mention
name_attach() returning an error if the name already exists.
Murf
David Gibbs wrote:
Robert Krten <> nospam83@parse.com> > wrote:
What happened to _RESMGR_FLAG_EXCL, why was it removed?
And whats the correct workaround to ensure a no-race-condition
exclusive resmgr_attach?
Um…try a name_attach() first…whoever win’s the name_attach()
does the resmgr_attach()? >
-David
QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.
name_attach() IS calling resmgr_attach() (may change later though), but
it have special arrangement.
-
non-root application CAN call name_attach() (normally only root
applicaiton
can resmgr_attach())
-
because of one, no multiple attach to same name. (otherwise, you can have
a
bad non-root guy, just attach to same name and “hijack” your clients).
-
is translated to “exclusively attach”
-xtang
John A. Murphy <murf@perftech.com> wrote in message
news:3E26BE21.D02DAACF@perftech.com…
David, could you give us some detail on how that works? I thought
name_attach() just called resmgr_attach. Also, the docs don’t mention
name_attach() returning an error if the name already exists.
Murf
David Gibbs wrote:
Robert Krten <> nospam83@parse.com> > wrote:
What happened to _RESMGR_FLAG_EXCL, why was it removed?
And whats the correct workaround to ensure a no-race-condition
exclusive resmgr_attach?
Um…try a name_attach() first…whoever win’s the name_attach()
does the resmgr_attach()? >
-David
QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.
Wow, now I’m really confused! I don’t see how 2) follows from 1), and looking
at the source for name_attach() in the CVS log for lib/c/dispatch/name.c I don’t
see how the difference between root and non-root applications is detected. What
am I missing?
Murf
Xiaodan Tang wrote:
name_attach() IS calling resmgr_attach() (may change later though), but
it have special arrangement.
-
non-root application CAN call name_attach() (normally only root
applicaiton
can resmgr_attach())
-
because of one, no multiple attach to same name. (otherwise, you can have
a
bad non-root guy, just attach to same name and “hijack” your clients).
-
is translated to “exclusively attach” >
-xtang
John A. Murphy <> murf@perftech.com> > wrote in message
news:> 3E26BE21.D02DAACF@perftech.com> …
David, could you give us some detail on how that works? I thought
name_attach() just called resmgr_attach. Also, the docs don’t mention
name_attach() returning an error if the name already exists.
Murf
David Gibbs wrote:
Robert Krten <> nospam83@parse.com> > wrote:
What happened to _RESMGR_FLAG_EXCL, why was it removed?
And whats the correct workaround to ensure a no-race-condition
exclusive resmgr_attach?
Um…try a name_attach() first…whoever win’s the name_attach()
does the resmgr_attach()? >
-David
QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.
John A. Murphy <murf@perftech.com> wrote in message
news:3E26D305.B974DB39@perftech.com…
Wow, now I’m really confused! I don’t see how 2) follows from 1), and
looking
at the source for name_attach() in the CVS log for lib/c/dispatch/name.c I
don’t
see how the difference between root and non-root applications is detected.
What
am I missing?
The enforcement is in the path manager (procnto). It check for any attach of
_FTYPE_NAME, and let non-root application attach it if the path is not
taken.
If you have an application name_attach() “mysrv”. If no exclusive enforced,
somebody could name_attach() “mysrv” again, and “cheat” the clients doing
name_open(“mysrv”) that he IS you. This is not a threat for resmgr_attach(),
because the “somebody” have to obtain root permissition to attach.
-xtang
Murf
Xiaodan Tang wrote:
name_attach() IS calling resmgr_attach() (may change later though), but
it have special arrangement.
-
non-root application CAN call name_attach() (normally only root
applicaiton
can resmgr_attach())
-
because of one, no multiple attach to same name. (otherwise, you can
have
a
bad non-root guy, just attach to same name and “hijack” your
clients).
-
is translated to “exclusively attach” >
-xtang
John A. Murphy <> murf@perftech.com> > wrote in message
news:> 3E26BE21.D02DAACF@perftech.com> …
David, could you give us some detail on how that works? I thought
name_attach() just called resmgr_attach. Also, the docs don’t mention
name_attach() returning an error if the name already exists.
Murf
David Gibbs wrote:
Robert Krten <> nospam83@parse.com> > wrote:
What happened to _RESMGR_FLAG_EXCL, why was it removed?
And whats the correct workaround to ensure a no-race-condition
exclusive resmgr_attach?
Um…try a name_attach() first…whoever win’s the name_attach()
does the resmgr_attach()? >
-David
QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.