Today xenstored tries to open a tdb data base file on disk when it is
started. As this is problematic in most cases the scripts used to start
xenstored ensure xenstored won't find such a file in order to start
with an empty xenstore.
A tdb data base file can't be used to restore all Xenstore state as
e.g. Xenstore watches are not kept in the tdb data base. The file is
meant to be used for debugging purposes after a xenstored crash only.
Instead of opening a Xenstore data base file found on disk always start
with an empty data base. This will avoid problems in case someone is
testing multiple xenstored versions without rebooting (which is not
supported but helps debugging in some cases).
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Commit 9e49dcf67f ("xenstore: add per-node generation counter) changed
the TDB layout, which - in order to not break older xenstored running
on the same system - need to be accompanied by a version bump.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Commit d4016288ab ("xenstore: support XS_DIRECTORY_PART in
libxenstore") introduced a theoretical bug: the generation count of
the read node is transferred via strncpy without forcing a NUL byte
at the end. Correct this.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Instead of always allocating a data buffer for incoming or outgoing
xenstore wire data add a small buffer to the buffered_data structure
of xenstored. This has the advantage that especially sending simple
response messages like errors or "OK" will no longer need allocating
a data buffer. This requires adding a memory context where the
allocated buffer was used for that purpose.
In order to avoid allocating a new buffered_data structure for each
response reuse the structure of the original request. This in turn
will avoid any new memory allocations for sending e.g. an ENOMEM
response making it possible to send it at all. To do this the
allocation of the buffered_data structure for the incoming request
must be done when a new request is recognized instead of doing it
when accepting a new connect.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
The xenstore wire command argument parsing of the different commands
is repeating some patterns multiple times. Add some helper functions
to avoid the duplicated code.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Move functions used in only one source to the file where they are used
and make them static.
Remove some prototypes from headers which are no longer in use.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Add a return value to all wire command functions of xenstored. If such
a function returns an error send the error message in
process_message().
Only code refactoring, no change in behavior expected.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Instead of switch() statements for selecting wire command actions use
an array for this purpose.
While doing this add the XS_RESTRICT type for diagnostic prints and
correct the printed string for XS_IS_DOMAIN_INTRODUCED.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
This will enable all users of libxenstore to handle xenstore nodes
with a huge amount of children.
In order to not depend completely on the XS_DIRECTORY_PART
functionality use it only in case of E2BIG returned by XS_DIRECTORY.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
As the payload size for one xenstore wire command is limited to 4096
bytes it is impossible to read the children names of a node with a
large number of children (e.g. /local/domain in case of a host with
more than about 2000 domains). This effectively limits the maximum
number of domains a host can support.
In order to support such long directory outputs add a new wire command
XS_DIRECTORY_PART which will return only some entries in each call and
can be called in a loop to get all entries.
Input data are the path of the node and the byte offset into the child
list where returned data should start.
Output is the generation count of the node (which will change each time
the node is being modified) and a list of child names starting with
the specified index. The end of the list is indicated by an empty
child name. It is the responsibility of the caller to check for data
consistency by comparing the generation counts of all returned data
sets to be the same for one node.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
In order to be able to support reading the list of a node's children in
multiple chunks (needed for list sizes > 4096 bytes) without having to
allocate a temporary buffer we need some kind of generation counter for
each node. This will help to recognize a node has changed between
reading two chunks.
As removing a node and reintroducing it must result in different
generation counts each generation value has to be globally unique. This
can be ensured only by using a global 64 bit counter.
For handling of transactions there is already such a counter available,
it just has to be expanded to 64 bits and must be stored in each
modified node.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
The layout of the tdb record of xenstored is defined at multiple
places: read_node(), write_node() and in xs_tdb_dump.c
Use a common structure instead.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Instead of calling add_change_node() at places where write_node() is
called, do that inside write_node().
Note that there is one case where add_change_node() is called now when
a later failure will prohibit the changed node to be written: in case
of a write_node failing due to an error in tdb_store(). As the only
visible change of behavior is a stale event fired for the node, while
the failing tdb_store() signals a corrupted xenstore database, the
stale event will be the least problem of this case.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
In order to prepare adding a generation count to each node modify
add_change_node() to take the connection pointer and a node pointer
instead of the transaction pointer and node name as parameters. This
requires moving the call of add_change_node() from do_rm() to
delete_node_single().
While at it correct the comment for the prototype: there is no
longjmp() involved.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
add_change_node() in xenstored is used to add a modified node to the
list of changed nodes of one transaction. It is being called with the
recurse parameter set to true when removing a node in order to get
watches for children of the node fired at transaction end, too.
If, however, the node to be deleted had been modified in the same
transaction the recurse parameter of add_change_node() is lost as
an entry already in the list of the changed nodes won't be entered
again.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
Blktap2 is effectively dead code for a few years.
Notable changes in this patch:
0. Unhook blktap2 from build system
1. Now libxl no longer supports TAP disk backend, appropriate assertions
are added and some code paths now return ERROR_FAIL
2. Tap is no longer a supported backend in doc
3. Remove relevant entries in MAINTAINERS
A patch to actually remove blktap2 directory will come later.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: George Dunlap <George.Dunlap@eu.citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
On a system with systemd the xenstore sockets are created via systemd.
Remove the related configuration files in order to be able to decide
at runtime whether the sockets should be created or not. This will
enable Xen to start xenstore either via a daemon or via a stub domain.
As the xenstore domain start program will exit after it has done its
job prepare the same behaviour to be tolerated by systemd for the
xenstore daemon by specifying the appropriate flags in the service
file.
A rerun of autogen.sh is required.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: David Scott <dave@recoil.org>
If memfile is NULL, the signal handler won't be installed, hence fopen
won't dereference NULL. Coverity is not smart enough to figure that out
unfortunately.
Add an assertion to prevent coverity from complaining.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
XenServer's coverity instance complains that a few lines below
create_node dereferences NULL if name == NULL. It however fails to
figure out that if node is NULL, errno won't be ENOENT, so do_mkdir
should have bailed before create_node.
That said, it would be good if we don't need to go through the hops. We
can bail earlier if name is NULL.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Add support for debugging memory allocation statistics to xenstored.
Specifying "-M <file>" on the command line will enable the feature.
Whenever xenstored receives SIGUSR1 it will dump out a full talloc
report to <file>. This helps finding e.g. memory leaks in xenstored.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Use a temporary memory context for memory allocations when firing
watches. This will avoid leaking memory in case of long living
connections and/or xenstore entries.
This requires adding a new parameter to fire_watches() and add_event()
to specify the memory context to use for allocations.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Add a parameter to xenstored get_node() function to explicitly
specify the memory context to be used for allocations. This will make
it easier to avoid memory leaks by using a context which is freed
soon.
This requires adding the temporary context to errno_from_parents() and
ask_parents(), too.
When calling get_node() select a sensible memory context for the new
parameter by preferring a temporary one.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Add a parameter to xenstored read_node() function to explicitly
specify the memory context to be used for allocations. This will make
it easier to avoid memory leaks by using a context which is freed
soon.
When calling read_node() select a sensible memory context for the new
parameter by preferring a temporary one.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Add a parameter to xenstored get_parent() function to explicitly
specify the memory context to be used for allocations. This will make
it easier to avoid memory leaks by using a context which is freed
soon.
When available use a temporary context when calling get_parent(),
otherwise mimic the old behavior by calling get_parent() with the same
argument for both parameters.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
In order to be able to avoid leaving temporary memory allocated after
processing of a command in xenstored call all command functions with
the temporary "in" context. Each function can then make use of that
temporary context for allocating temporary memory instead of either
leaving that memory allocated until the connection is dropped (or
even until end of xenstored) or freeing the memory itself.
This requires to modify the interfaces of the functions taking only
one argument from the connection by moving the call of onearg() into
the single functions. Other than that no functional change.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
xs_perm_to_string takes a size_t which isn't defined by anything
pulled in directly by this header.
Given the other headers xenstore_lib.h pulls in this looks to be an
oversight rather than a deliberate policy.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
libxenforeignmemory will provide a stable API and ABI for mapping
foreign domain memory (subject to appropriate privileges).
The new library exposes an interface equivalent to
xc_map_foreign_memory_bulk, which all the other
xc_map_foreign_memory_* functions (which remain in libxc) are
implemented in terms of.
Upon request (via #define XC_WANT_COMPAT_MAP_FOREIGN_API) libxenctrl
will provide a compat API for the old names. This is used by qemu-xen
and qemu-trad as well as various in tree things (which required
de-dupping various #includes in some too to get the #define before the
first).
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
[ ijc -- updated MINIOS_UPSTREAM_REVISION and QEMU_TRADITIONAL_REVISION ]
libxengnttab will provide a stable API and ABI for accessing the
grant table devices.
The functions are moved into the xengnt{tab,shr} namespace to make a
clean break from libxc and avoid ambiguity regarding which interfaces
are stable.
All in-tree users are updated to use the new names.
Upon request (via #define XC_WANT_COMPAT_GNTTAB_API) libxenctrl will
provide a compat API for the old names. This is used by qemu-xen for
the time being. qemu-xen-traditional is updated in lockstep.
This leaves a few grant table related functions which go via privcmd
(GNTTABOP) rather than ioctls on the /dev/xen/gnt* devices in
libxenctrl. Specifically:
- xc_gnttab_get_version
- xc_gnttab_map_table_v1
- xc_gnttab_map_table_v2
- xc_gnttab_op
These functions do not appear to be needed by qemu-dm, qemu-pv
(provision of device model to HVM guests and PV backends respectively)
or by libvchan suggesting they are not needed by non-toolstack uses of
event channels.
The new library uses a version script to ensure that only expected
symbols are exported and to version them such that ABI guarantees can
be kept in the future.
After this change libxenvchan no longer needs to link against
libxenctrl. It still needs xenctrl.h in one file for xen_mb and
friends.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
[ ijc -- updated MINIOS_UPSTREAM_REVISION and QEMU_TRADITIONAL_REVISION ]
libxenevtchn will provide a stable API and ABI for accessing the
evtchn device.
The functions are moved into the xenevtchn namespace to make a clean
break from libxc and avoid ambiguity regarding which interfaces are
stable.
All in-tree users are updated to use the new names.
Upon request (via #define XC_WANT_COMPAT_EVTCHN_API) libxenctrl will
provide a compat API for the old names. This is used by qemu-xen for
the time being. qemu-xen-traditional is updated in lockstep.
This leaves a few event channel related functions which go via privcmd
(EVTCHNOP) rather than ioctls on the /dev/xen/evtchn device in
libxenctrl. Specifically:
- xc_evtchn_alloc_unbound
- xc_evtchn_reset
- xc_evtchn_status
Note that xc_evtchn_alloc_unbound's functionality is also provided by
xenevtchn_bind_unbound_port() (née xc_evtchn_bind_unbound_port) and is
probably redundant.
These functions do not appear to be needed by qemu-dm, qemu-pv
(provision of device model to HVM guests and PV backends respectively)
or by libvchan suggesting they are not needed by non-toolstack uses of
event channels. QEMU does use these in hw/xenpv/xen_domainbuild.c but
that is a "toolstack use".
The new library uses a version script to ensure that only expected
symbols are exported and to version them such that ABI guarantees can
be kept in the future.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
[ ijc -- updated MINIOS_UPSTREAM_REVISION and QEMU_TRADITIONAL_REVISION ]
The program init-xenstore-domain to start a xenstore domain instead
of the xenstored daemon is built, but not installed. Change that.
Move the program to a new tools subdirectory "helpers" to be able to
use libxl in a later patch. Otherwise a dependency loop will be
created.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
With the addition of HVMlite the hypervisor now always requires a non-null
arch domain config, which is different between HVM and PV guests.
Add a new parameter to xc_domain_create that contains a pointer to an arch
domain config. If the pointer is null, create a default arch domain config
based on guest type.
Fix all the in-tree callers to provide a null arch domain config in order to
mimic previous behaviour.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
With the addition of FMODE_ATOMIC_POS in the Linux 3.14 kernel,
concurrent blocking file accesses to a single open file descriptor can
cause a deadlock trying to grab the file position lock. If a watch has
been set up, causing a read_thread to blocking read on the file
descriptor, then future writes that would cause the background read to
complete will block waiting on the file position lock before they can
execute. This race condition only occurs when libxenstore is accessing
the xenstore daemon through the /proc/xen/xenbus file and not through
the unix domain socket, which is the case when the xenstore daemon is
running as a stub domain or when oxenstored is passed
--disable-socket. Accessing the daemon from the true character device
also does not exhibit this problem.
On Linux, prefer using the character device file over the proc file if
the character device exists.
Signed-off-by: Jonathan Creekmore <jonathan.creekmore@gmail.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
C requires that every use of va_copy() is matched with a va_end() call.
This is especially important for x86_64 as va_{start,copy}() may need to
allocate memory to generate a va_list containing parameters which were
previously in registers.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
There were two problems with original code:
1. sd_booted() was used to determined if the process was started by
systemd, which was wrong.
2. Exit with error if pidfile was specified, which was too harsh.
These two combined made cxenstored unable to start by hand if it ran
on a system which had systemd.
Fix issues with following changes:
1. Use sd_listen_fds to determine if the process is started by systemd.
2. Don't exit if pidfile is specified.
Rename function and restructure code to make things clearer.
A side effect of this patch is that gcc 4.8 with -Wmaybe-uninitialized
in non-debug build spits out spurious warning about sock and ro_sock
might be uninitialized. Since CentOS 7 ships gcc 4.8, we need to work
around that by setting sock and ro_sock to NULL at the beginning of
main.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Tested-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
As recommended in http://www.gnu.org/licenses/gpl-howto.en.html.
This is the result of:
$ git grep -El Mass\|Temple\|Franklin | xargs ./fsf.pl
Where fsf.pl is:
#!/usr/bin/perl -w -pi.bak -0777
my $repl = 'If not, see <http://www.gnu.org/licenses/>.';
my $br = qr/(?:\s*\n\s*(?:[\*\#]|\/\/|\.\\" )?\s*|\s+)/;
my $inwt = qr/[Ii]f${br}not,${br}write${br}(?:to${br})?the${br}Free${br}Software${br}Foundation,(?:${br}Inc\.,)?/;
my $mass = qr/675${br}Mass${br}Ave,?${br}Cambridge,?${br}MA${br}02139,?${br}USA,?\.?/;
my $franklin = qr/51${br}Franklin${br}St(?:reet)?(?:,${br}| - )Fifth${br}Floor,?${br}Boston,?${br}MA,?${br}02110-1301,?${br}USA,?\.?/;
my $temple = qr/59${br}Temple${br}Place(?:,${br}| - )Suite${br}330,?${br}Boston,?${br}MA,?${br}021110?-1307,?${br}USA,?\.?/;
s|$inwt$br$mass|$repl|m;
s|$inwt$br$franklin|$repl|m;
s|$inwt$br$temple|$repl|m;
The only remaining mentions of these addresses are in COPYING files which I
haven't touched.
Some of the changed files are imports from elsewhere, however
filtering them out is tricky, I think it is tolerable to have these
files be modified here and then perhaps reverted on the next sync,
since it's only 1-2 lines and obvious what is going on.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Instead switch to an explicit -include $(XEN_ROOT)/tools/config.h to
pickup config.h.
Most places already do this, fixup the rest.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Linux may not use the same page granularity as Xen. This will result to
a domain crash because it will try to map more page than required.
As the xenstore page size willl always be equal to a Xen page size, use
XC_PAGE_SIZE.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Coverity uses several heuristics to identify when one case statement
legitimately falls through into the next, and a comment as the final item in a
case statement is one heuristic (the assumption being that it is a
justification for the fallthrough).
Use this to perform an audit of defects and hide the legitimate fallthroughs.
There are two bugfixes identified in the audit, both minor:
* 'n' command line handling for gtracestat
* BKSPC handling in xentop
All other identified defaults are legitimate fallthoughs
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Coverity-IDs: 1055464, 1055465, 1055467, 1055468, 1055481, 1055482
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Xen Coverity Team <coverity@xen.org>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Don Koch <dkoch@verizon.com>
Wei Liu
Juergen Gross
Jan Beulich
Roger Pau Monne
Ian Campbell
Jonathan Creekmore
Andrew Cooper
Julien Grall
Olaf Hering