Since 28d386fc43 (XSA-57), libxl writes an empty value for the
console tty node, with read-only permission for the guest, when
setting up pv console "frontends". (The actual tty value is later set
by xenconsoled.) Writing an empty node is not strictly necessary to
stop the frontend from writing dangerous values here, but it is a good
belt-and-braces approach.
Unfortunately this confuses xenconsole. It reads the empty value, and
tries to open it as the tty. xenconsole then exits.
Fix this by having xenconsole treat an empty value the same way as no
value at all.
Also, make the error opening the tty be nonfatal: we just print a
warning, but do not exit. I think this is helpful in theoretical
situations where xenconsole is racing with libxl and/or xenconsoled.
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
CC: George Dunlap <george.dunlap@eu.citrix.com>
---
v2: Combine two conditions and move the free
If xenconsole (the client program) fails, it calls err. This would
previously neglect to reset the user's terminal to sanity. Use atexit
to do so.
This routinely happens in Xen 4.4 RC5 with pygrub because libxl
writes the value "" to the tty xenstore key when using xenconsole.
After this patch this just results in a harmless error message.
Reported-by: M A Young <m.a.young@durham.ac.uk>
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: M A Young <m.a.young@durham.ac.uk>
CC: Ian Campbell <Ian.Campbell@citrix.com>
Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
---
v2: Fix whitespace error (reintroduce hard tab)
Fix commit message not to claim ignorance about root cause
Currently we check the pty path received from xenstore with access(); if
it indicates that the pty is not accessible, we loop around and wait for
a new path to appear in xenstore.
This has several issues:
* If a path has been written to xenstore, it can be assumed that that
pty should already be accessible to xenconsole, and hence any error
that occurs while trying to open it should be fatal and not ignored
* If access() indicates no access to the pty, the memory allocated for
the path is leaked when going around the loop again
* The accessibility of the pty could change between the access() and
open() calls, leading to a TOCTOU race (this is what Coverity is
complaining about).
By removing the explicit access() check and just erroring out whenever
open() fails, we fix all these issues.
Coverity-ID: 1056047
Signed-off-by: Matthew Daley <mattd@bugfuzz.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
The xenstore header xs.h is producing conflicts with other software[1].
xs is a too short identifier and does not matche the library. Renaming
the headers to xenstore.h and xenstore_lib.h is the easiest way to make
them easy recognizable and prevent furthe problems.
[1]: http://bugs.debian.org/668550
[ Also update QEMU_TAG, to bring in corresponding change to
qemu-xen-traditional. -iwj ]
Signed-off-by: Bastian Blank <waldi@debian.org>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
--HG--
rename : tools/xenstore/xs.h => tools/xenstore/xenstore.h
rename : tools/xenstore/xs_lib.h => tools/xenstore/xenstore_lib.h
This patch implements the new protocol for handling pv consoles and
emulated serials as described in the document docs/misc/console.txt.
The changes are:
- xenconsoled: do not write the pty under serial in xenstore if
xenconsoled is handling a consolepath;
- xenconsole: implement support for an explicit console type parameter;
the parameter can be "pv", to specify that the user wants to
connect to a pv console, or "serial", to specify that the user wants to
connect to an emulated serial. If the type parameter hasn't been
specified be the user, xenconsole tries to guess which type of console
it has to connect to, defaulting to pv console for pv guests and
emulated serial for hvm guests.
- xenconsole: use the new xenstore paths;
- libxl: rename libxl_console_constype to libxl_console_consback:
constype is used to to specify whether qemu or xenconsoled provides the
backend, so I renamed it to libxl_console_consback to make it more
obvious that we are talking about backends;
- libxl: add a new libxl_console_constype to specify if the console is
an emulated serial or a pv console;
- libxl: support the new xenconsole "type" command line parameter;
- libxl: use the "output" node under console in xenstore to tell qemu
where do we want the output of this pv console to go;
- remove the legacy "serialpath" from xenconsoled altogether
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Also: update the QEMU_TAG to pull in the qemu part of these changes.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
This can just mean we have raced with the bootloader exiting and if we
continue we will likely see the real domain console show up.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Segmentation fault occurs if DOMID isn't specified.
Some check be added to output error message in this situation.
Signed-off-by: Yu Zhiguo <yuzg@cn.fujitsu.com>
This patch adds a new command line argument to xenconsole to specify
to which console to connect to in case a domain has more than one.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Make sure that tty semantics are active for Solaris ptys, or if they
aren't (and not needed) to not do tcget/setattr on the filedescriptor
in Python code.
Also work around a bug in the Solaris ptm streams driver, which will
cause a write error on the master side of a pty (because of e.g. a
missing slave) to persist forever.
Signed-off-by: Frank van der Linden <frank.vanderlinden@sun.com>
- include headers needed to build on NetBSD
- Remove unused pty.h
- Initialize spty terminal before actually using it
Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
- xend forwards console traffic between the running bootloader and a pty
which it writes to the store so the xenconsole client can see it.
- the xenconsole client handles the domain's console pty changing.
- xm create no longer runs the bootloader.
- pygrub gets '-i' option to explicitly request an interactive session.
- xend unlocks the domain list during bootloading so that "xm console"
can see the domain and attach to its console pty.
Signed-off-by: Tim Deegan <Tim.Deegan@xensource.com>
the intention appears to have been 500msec, but struct timeval when used with
a select() is in usec, not msec. The timeout has been set to 250msec (500msec
seems a little long, in any case).
Signed-off-by: Ewan Mellor <ewan@xensource.com>
handle on appropriate operations. Next step is to plug this
through to the store daemon and get rid of the nasty serialisation
mutex for transactions.
Signed-off-by: Keir Fraser <keir@xensource.com>
There is a race condition that occurs after xend creates a domain.
The console client might be running before the console daemon has
noticed the new domain and setup a pty for it.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Ian Jackson
Matthew Daley
Andrew Cooper
Ian Campbell
Stefano Stabellini
Keir Fraser
Keir Fraser
Tim Deegan
Ewan Mellor
kaf24@firebug.cl.cam.ac.uk
emellor@leeni.uk.xensource.com
vhanquez@kneesa.uk.xensource.com
cl349@firebug.cl.cam.ac.uk