Building with gnutls 3.2.0 (such as shipped with current cygwin) fails
with:
rpc/virnettlscontext.c: In function 'virNetTLSSessionGetKeySize':
rpc/virnettlscontext.c:1358:5: error: implicit declaration of function 'gnutls_cipher_get_key_size' [-Wimplicit-function-declaration]
Yeah, it's stupid that gnutls broke API by moving their declaration
into a new header without including that header from the old one,
but it's easy enough to work around, all without breaking on gnutls
1.4.1 (hello RHEL 5) that lacked the new header.
* configure.ac (gnutls): Check for <gnutls/crypto.h>.
* src/rpc/virnettlscontext.c (includes): Include additional header.
Signed-off-by: Eric Blake <eblake@redhat.com>
https://www.gnu.org/licenses/gpl-howto.html states:
You should also include a copy of the license itself somewhere in the
distribution of your program. All programs, whether they are released
under the GPL or LGPL, should include the text version of the GPL. In
GNU programs the license is usually in a file called COPYING.
If you are releasing your program under the LGPL, you should also
include the text version of the LGPL, usually in a file called
COPYING.LESSER. Please note that, since the LGPL is a set of
additional permissions on top of the GPL, it's important to include
both licenses so users have all the materials they need to understand
their rights.
* configure.ac (COPYING): No more games with non-git file.
* COPYING: New file, copied from gnulib.
* COPYING.LIB: Rename...
* COPYING.LESSER: ...to this.
* .gitignore: Track licenses in git.
* cfg.mk (exclude_file_name_regexp--sc_copyright_address): Tweak
rule.
* libvirt.spec.in (daemon, client, python): Reflect rename.
Signed-off-by: Eric Blake <eblake@redhat.com>
Clang does not like the -export-dynamic flag. The compiler does
not need it in the first place, so we can avoid the problem by
only setting it for the linker
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
When combining old gcc (4.2.1) and new gcrypt (1.5.2), such as
when using the Ports repository on FreeBSD, the build fails with:
CC libvirt_driver_la-libvirt.lo
cc1: warnings being treated as errors
In file included from libvirt.c:58:
/usr/local/include/gcrypt.h:1336: warning: 'gcry_ac_io_mode_t' is deprecated [-Wdeprecated-declarations]
Relevant part of gcrypt.h:
1333 typedef struct gcry_ac_io
1334 {
1335 /* This is an INTERNAL structure, do NOT use manually. */
1336 gcry_ac_io_mode_t mode _GCRY_ATTR_INTERNAL;
1337 gcry_ac_io_type_t type _GCRY_ATTR_INTERNAL;
1338 union
The sad part is that we aren't even using the deprecated symbols - their
mere inclusion in the installed header is provoking the problems. It
looks like newer gcc is a bit more tolerant (that is, this is a
shortcoming of FreeBSD's use of an older compiler).
Signed-off-by: Eric Blake <eblake@redhat.com>
- provide virNetDevSetMAC() implementation based on SIOCSIFLLADDR
ioctl.
- adjust virNetDevExists() to check for ENXIO error because
FreeBSD throws it when device doesn't exist
Signed-off-by: Eric Blake <eblake@redhat.com>
FreeBSD (and maybe other BSDs) have different member
names in struct ifreq when compared to Linux, such as:
- uses ifr_data instead of ifr_newname for setting
interface names
- uses ifr_index instead of ifr_ifindex for interface
index
Also, add a check for SIOCGIFHWADDR for virNetDevValidateConfig().
Use AF_LOCAL if AF_PACKET is not available.
Signed-off-by: Eric Blake <eblake@redhat.com>
This patch adds two sets of functions:
1) lower level virProcessSet*() functions that will immediately set
the RLIMIT_MEMLOCK. RLIMIT_NPROC, or RLIMIT_NOFILE of either the
current process (using setrlimit()) or any other process (using
prlimit()). "current process" is indicated by passing a 0 for pid.
2) functions for virCommand* that will setup a virCommand object to
set those limits at a later time just after it has forked a new
process, but before it execs the new program.
configure.ac has prlimit and setrlimit added to the list of functions
to check for, and the low level functions log an "unsupported" error)
on platforms that don't support those functions.
Add a virCgroupIsolateMount method which looks at where the
current process is place in the cgroups (eg /system/demo.lxc.libvirt)
and then remounts the cgroups such that this sub-directory
becomes the root directory from the current process' POV.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
On Win32 symlink() is not available, so virstoragetest.c
must be conditionalized to avoid compile failures.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
By passing the flags -z relro -z now to the linker, we can force
it to resolve all library symbols at startup, instead of on-demand.
This allows it to then make the global offset table (GOT) read-only,
which makes some security attacks harder.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
PIE (position independent executable) adds security to executables
by composing them entirely of position-independent code (PIC. The
.so libraries already build with -fPIC. This adds -fPIE which is
the equivalent to -fPIC, but for executables. This for allows Exec
Shield to use address space layout randomization to prevent attackers
from knowing where existing executable code is during a security
attack using exploits that rely on knowing the offset of the
executable code in the binary, such as return-to-libc attacks.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Every source file is currently built twice by libtool, once for
the shared library and once for the static library. Static libs
are not commonly packaged by distros and slow down compilation
time by more than 50% compared to a shared-only build time.
Time for 'make -j 4':
shared only: 2 mins 9 secs
shared + static: 3 mins 26 secs
Time for non-parallel make
shared only: 3 mins 32 secs
shared + static: 5 mins 41 secs
Those few people who really want them, can pass --enable-static
to configure
Disabling them by default requires use of LT_INIT, but for
compat with RHEL5 we can't rely on that. So we conditionally
use LT_INIT, but fallback to AM_PROG_LIBTOOL if not present.
Commit c308a9ae was incomplete; it resolved the configure failure,
but not a later build failure.
* src/util/virnetdevbridge.c: Include pre-req header.
* configure.ac (AC_CHECK_HEADERS): Prefer standard in.h over
non-standard ip6.h.
Some places missed the conversion from LIBCURL_{CFLAGS,LIBS} to
CURL_{CFLAGS,LIBS}, and a part of curl check was left in
configure.ac instead of m4/virt-curl.m4 by mistake
I got this scary warning during ./configure on rawhide:
checking linux/if_bridge.h usability... no
checking linux/if_bridge.h presence... yes
configure: WARNING: linux/if_bridge.h: present but cannot be compiled
configure: WARNING: linux/if_bridge.h: check for missing prerequisite headers?
configure: WARNING: linux/if_bridge.h: see the Autoconf documentation
configure: WARNING: linux/if_bridge.h: section "Present But Cannot Be Compiled"
configure: WARNING: linux/if_bridge.h: proceeding with the compiler's result
configure: WARNING: ## ------------------------------------- ##
configure: WARNING: ## Report this to libvir-list@redhat.com ##
configure: WARNING: ## ------------------------------------- ##
checking for linux/if_bridge.h... no
* configure.ac (AC_CHECK_HEADERS): Provide struct in6_addr, since
linux/if_bridge.h uses it without declaring it.
This patch introduces support for LXC specific public APIs. In
common with what was done for QEMU, this creates a libvirt_lxc.so
library and libvirt/libvirt-lxc.h header file.
The actual APIs are
int virDomainLxcOpenNamespace(virDomainPtr domain,
int **fdlist,
unsigned int flags);
int virDomainLxcEnterNamespace(virDomainPtr domain,
unsigned int nfdlist,
int *fdlist,
unsigned int *noldfdlist,
int **oldfdlist,
unsigned int flags);
which provide a way to use the setns() system call to move the
calling process into the container's namespace. It is not
practical to write in a generically applicable manner. The
nearest that we could get to such an API would be an API which
allows to pass a command + argv to be executed inside a
container. Even if we had such a generic API, this LXC specific
API is still useful, because it allows the caller to maintain
the current process context, in particular any I/O streams they
have open.
NB the virDomainLxcEnterNamespace() API is special in that it
runs client side, so does not involve the internal driver API.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
There are many aspects of the guest XML which result in the
SELinux driver applying file labelling. With the increasing
configuration options it is desirable to test this behaviour.
It is not possible to assume that the test suite has the
ability to set SELinux labels. Most filesystems though will
support extended attributes. Thus for the purpose of testing,
it is possible to extend the existing LD_PRELOAD hack to
override setfilecon() and getfilecon() to simply use the
'user.libvirt.selinux' attribute for the sake of testing.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This converts the libssh2 configure check to use LIBVIRT_CHECK_PKG.
Previously it would check version 1.0 and 1.3, but this simplifies
things to just require version 1.3
I ran 'make dist' in the directory left over from ./autobuild.sh
(which was configured for a mingw cross build); the resulting
tarball had more files than 'make dist' on a normal Linux build.
I traced it to the fact that we were distributing a generated
file, but only when configure said the end user had to generate
the file in the first place. In the process, I noticed that
we had some difference in symbol file names; I added a comment
explaining why the difference exists (after first trying to
normalize the names and hitting VPATH build failures).
* configure.ac (LIBVIRT_QEMU_SYMBOL_FILE): Add some comments.
* src/Makefile.am (EXTRA_DIST): No need to ship a generated file;
particularly since which file is built depends on configure results.
Commit dfa1e1dd removed libxenctrl from LIBXL_LIBS, but the libxl
driver uses a symbol from this library. Explicitly link with
libxenctrl instead of relying on the build system to support
implicit DSO linking.
The functionality provided in virchrdev.c (previously virconsole.c) is
applicable to other types of character devices besides consoles, such
as channels. This patch is just code motion, renaming things such as
"console" or "pty", instead using more general terms such as
"character device" or "device path".
A recent build failure made me realize that we could usefully add
a bit more information to configure output, for aid in analysis of
failed builds. Pulling in the autobuild module merely adds these
four lines to configure output:
configure: autobuild project... libvirt
configure: autobuild revision... v1.0.1-113-g7a74eea
configure: autobuild hostname... myhost
configure: autobuild timestamp... 20130102T233543Z
which can be useful even if not using the Autobuild project to parse
build logs.
* bootstrap.conf (gnulib_modules): Add autobuild.
* configure.ac: Favor git version over release version, when available.
Commit 8b8fcdea introduced a check for broken gcc -Wlogical-op,
but did not guard the check against non-gcc compilers, which might
lead to spurious failures when another compiler encounters an
unknown pragma. Additionally, all of our compiler warning logic
should belong in a single file, and use cache variables to allow
overriding the decision at configure time if necessary.
* configure.ac (BROKEN_GCC_WLOGICALOP): Move...
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS): ...here,
and update to modern autoconf idioms.
Some older versions of GCC report a false positive on code like
char * haystack, needle;
strchr(haystack, needle);
Added an extra check in configure.ac which will
#define BROKEN_GCC_WLOGICALOP 1
in this case, allowing to special handle "offending" code.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
This adds an implementation of virNetSocketGetUNIXIdentity()
using LOCAL_PEERCRED socket option and xucred struct, defined
in <sys/ucred.h> on systems that have it.
* Autotools changes:
- Don't assume Qemu is Linux-only
- Check Linux headers only on Linux
- Disable firewalld on FreeBSD
* Initctl:
Initctl seem to present only on Linux, so stub it on other platforms
* Raw I/O: Linux-only as well
* Headers cleanup
Based on a patch originally authored by Daniel De Graaf
http://lists.xen.org/archives/html/xen-devel/2012-05/msg00565.html
This patch converts the Xen libxl driver to support only Xen >= 4.2.
Support for Xen 4.1 libxl is dropped since that version of libxl is
designated 'technology preview' only and is incompatible with Xen 4.2
libxl. Additionally, the default toolstack in Xen 4.1 is still xend,
for which libvirt has a stable, functional driver.
It may take some time for sanlock to add a lockspace. And if user
restart libvirtd service meanwhile, the fresh daemon can fail adding
the same lockspace with EINPROGRESS. Recent sanlock has
sanlock_inq_lockspace() function which should block until lockspace
changes state. If we are building against older sanlock we should
retry a few times before claiming an error. This issue can be easily
reproduced:
for i in {1..1000} ; do echo $i; service libvirtd restart; sleep 2; done
20
Stopping libvirtd daemon: [FAILED]
Starting libvirtd daemon: [ OK ]
21
Stopping libvirtd daemon: [ OK ]
Starting libvirtd daemon: [ OK ]
22
Stopping libvirtd daemon: [ OK ]
Starting libvirtd daemon: [ OK ]
error : virLockManagerSanlockSetupLockspace:334 : Unable to add
lockspace /var/lib/libvirt/sanlock/__LIBVIRT__DISKS__: Operation now in
progress
* configure.ac docs/news.html.in libvirt.spec.in: update for the new release
* po/*.po*: update from transifex, a lot of added support e.g. Indian
languages, and regenerate
When using --without-$name --without-secdriver-$name with $name being
selinux or apparmor, configure will fail saying that AppArmor/SELinux
development package must be installed.
This is caused by a small bug in --with-secdriver-$name handling in
configure.ac which treats --without-secdriver-$name when $name as if the
user had requested to enable $name when $name couldn't be detected on
the system.
This commit also makes sure the detection checks for disabled
secdrivers do not needlessly get run, especially as this could
cause an error as well in --with-$name --without-secdriver-$name
situations.
libvirt started using sanlock_killpath to implement on_lockfailure
action. Since sanlock_killpath was introduced in sanlock 2.4, libvirt
fails to build with older sanlock.
We are currently able to work only with non-translated SELinux
contexts, but we are using functions that work with translated
contexts throughout the code. This patch swaps all SELinux context
translation relative calls with their raw sisters to avoid parsing
problems.
The problems can be experienced with mcstrans for example. The
difference is that if you have translations enabled (yum install
mcstrans; service mcstrans start), fgetfilecon_raw() will get you
something like 'system_u:object_r:virt_image_t:s0', whereas
fgetfilecon() will return 'system_u:object_r:virt_image_t:SystemLow'
that we cannot parse.
I was trying to confirm that the _raw variants were here since the dawn of
time, but the only thing I see now is that it was imported together in
the upstream repo [1] from svn, so before 2008.
Thanks Laurent Bigonville for finding this out.
[1] http://oss.tresys.com/git/selinux.git
Add a read-only udev based backend for virInterface. Useful for distros
that do not have netcf support yet. Multiple libvirt based utilities use
a HAL based fallback when virInterface is not available which is less
than ideal. This implements:
* virConnectNumOfInterfaces()
* virConnectListInterfaces()
* virConnectNumOfDefinedInterfaces()
* virConnectListDefinedInterfaces()
* virConnectListAllInterfaces()
* virConnectInterfaceLookupByName()
* virConnectInterfaceLookupByMACString()
curl_global_init is not thread-safe. curl_easy_init might call
curl_global_init when it was no called before. But curl_easy_init
can be called from different threads by the ESX driver. Therefore,
call curl_global_init from virInitialize to stop curl_easy_init from
calling it.
Reported by Benjamin Wang.
Commit f6430390 broke builds on RHEL 5, where glibc (2.5) is too
old to support mkostemp (2.7) or htole64 (2.9). While gnulib
has mkostemp, it still lacks htole64; and it's not worth dragging
in replacements on systems where journald is unlikely to exist
in the first place, so we just use an extra configure-time check
as our witness of whether to attempt compiling the code.
* src/util/logging.c (virLogParseOutputs): Don't attempt to
compile journald on older glibc.
* configure.ac (AC_CHECK_DECLS): Check for htole64.
Currently if you build on a machine that does not support SELinux we end up
with the default mount point being /selinux, since this is moved to
/sys/fs/selinux, we should start defaulting there.
I believe this is causing a bug in libvirt-lxc when /selinux does not exists,
even though /sys/fs/selinux exists.
In Xen 4.2, xs.h is deprecated in favor of xenstore.h. xs.h now
contains
#warning xs.h is deprecated use xenstore.h instead
#include <xenstore.h>
which fails compilation when warnings are treated as errors.
Introduce a configure-time check for xenstore.h and if found,
use it instead of xs.h.
Commit 9298bfbcb introduced code to detect if netcf is linked with
libnl1, and to prefer libnl1 over libnl3 when this is the case.
This behaviour can be disabled by setting LIBNL_CFLAGS to any value,
including the empty string.
However, configure.ac sets LIBNL_CFLAGS to "" before attempting
libnl detection, so the libnl1 detection code is always disabled.
This caused issues on my f17 system where netcf is linked with libnl1
but libvirt got built with libnl3.
This commit removes the setting of the LIBNL_* variables to "" as
this does not appear to be needed. After this change, libnl1 is
used when building libvirt on my f17 system.
Based exclusively on work by Eric Blake in a patch posted with the same
subject. However some modifications related to comments and my plans to
add another backend.
Added WITH_INTERFACE as the only automake variable deciding whether to
build the driver and using WITH_NETCF to identify that we're wanting to
use the netcf library as the backend.
* configure.ac: Added with_interface
* src/interface/netcf_driver.c: Renamed..
* src/interface/interface_backend_netcf.c: ..to this to match storage.
* src/interface/netcf_driver.h: Renamed..
* src/interface/interface_driver.h: ..to this.
* daemon/Makefile.am: Respect WITH_INTERFACE and WITH_NETCF.
* libvirt.spec.in: Add RPM support for --with-interface
With this script you can run libvirt programs without needing to
install them first. You just have to do for example:
./run ./tools/virsh [args ...]
If you are already in the tools/ subdirectory, then the following
command will also work:
../run ./virsh [...]
You can also run the C programs under valgrind like this:
./run valgrind [valgrind opts...] ./program
or under gdb:
./run gdb --args ./program
This also works with sudo (eg. if you need root access for libvirt):
sudo ./run ./tools/virsh list --all
Derived from libguestfs and simplified. The ./run script in
libguestfs is much more sophisticated:
https://github.com/libguestfs/libguestfs/blob/master/run.in
Commit 9298bfb changed configure to split the libnl into two
separate pkg config checks instead of nesting the second check
on the failure path of the first. But the default pkg config
behavior is to abort configure if a check fails. Since we have
a second check lined up, we need an explicit failure case that
does not abort if the first check fails.
Meanwhile, commit 51b708c is reverted. It did not fix any
behavior, and in fact, introduced a regression to the fallback
case when the user explicitly sets $LIBNL_CFLAGS.
* configure.ac: Don't abort if libnl-3 is not found.
Recent spec file changes ensure that in distro situations, netcf
and libvirt will link against the same libnl in order to avoid
dumping core. But for every-day development, if you use F17 and
have the libnl3-devel headers available, libvirt was blindly
linking against libnl3 even though F17 netcf still links against
libnl1, making testing a self-built binary on F17 impossible.
By making configure a little bit smarter, we can avoid this
situation - we merely skip the probe of libnl-3 if we can prove
that netcf is still using libnl-1. I intentionally wrote the
test so that we still favor libnl-3 if netcf is not installed or
if we couldn't use ldd to determine things.
Defaults being what they are, someone will invariably complain
that our smarts were wrong. Never fear - in that case, just run
./configure LIBNL_CFLAGS=..., where the fact that you set
LIBNL_CFLAGS (even to the empty string) will go back to probing
for libnl-3, regardless of netcf's choice.
* configure.ac (LIBNL): Don't probe libnl3 if netcf doesn't use it.
FreeBSD and OpenBSD have a <net/if.h> that is not self-contained;
and mingw lacks the header altogether. But gnulib has just taken
care of that for us, so we might as well simplify our code. In
the process, I got a syntax-check failure if we don't also take
the gnulib execinfo module.
* .gnulib: Update to latest, for execinfo and net_if.
* bootstrap.conf (gnulib_modules): Add execinfo and net_if modules.
* configure.ac: Let gnulib check for headers. Simplify check for
'struct ifreq', while also including enough prereq headers.
* src/internal.h (IF_NAMESIZE): Drop, now that gnulib guarantees it.
* src/nwfilter/nwfilter_learnipaddr.h: Use correct header for
IF_NAMESIZE.
* src/util/virnetdev.c (includes): Assume <net/if.h> exists.
* src/util/virnetdevbridge.c (includes): Likewise.
* src/util/virnetdevtap.c (includes): Likewise.
* src/util/logging.c (includes): Assume <execinfo.h> exists.
(virLogStackTraceToFd): Handle gnulib's fallback implementation.
On OpenBSD, clock_gettime() exists in libc rather than librt, and
blindly linking with -lrt made the build fail. Gnulib already
did the work for determining which libraries to use, so we should
reuse that work rather than doing it ourselves.
* bootstrap.conf (gnulib_modules): Pull in clock-time.
* configure.ac (RT_LIBS): Drop.
* src/Makefile.am (libvirt_util_la_LIBADD): Use gnulib variable
instead.
* src/util/virtime.c (includes): Simplify.
We already skip out on building the LXC under RHEL 5, because the
kernel is too old (commits 4c18acf, 2dee896); but commit 9612e4b
moved some LXC-only code into common files, resulting in this
build failure:
util/virfile.c: In function 'virFileLoopDeviceAssociate':
util/virfile.c:580: error: 'LO_FLAGS_AUTOCLEAR' undeclared (first use in this function)
Unfortunately, the kernel folks only made it an enum, rather than
also a #define, so we have to modify configure.ac to record when
it is usable.
* configure.ac (with_lxc): Mark when LO_FLAGS_AUTOCLEAR was found.
* src/util/virfile.c (virFileLoopDeviceAssociate): Avoid
compilation when kernel is too old.
* configure.ac, spec file: firewalld defaults to enabled if dbus is
available, otherwise is disabled. If --with_firewalld is explicitly
requested and dbus is not available, configure will fail.
* bridge_driver: add dbus filters to get the FirewallD1.Reloaded
signal and DBus.NameOwnerChanged on org.fedoraproject.FirewallD1.
When these are encountered, reload all the iptables reuls of all
libvirt's virtual networks (similar to what happens when libvirtd is
restarted).
* iptables, ebtables: use firewall-cmd's direct passthrough interface
when available, otherwise use iptables and ebtables commands. This
decision is made once the first time libvirt calls
iptables/ebtables, and that decision is maintained for the life of
libvirtd.
* Note that the nwfilter part of this patch was separated out into
another patch by Stefan in V2, so that needs to be revised and
re-reviewed as well.
================
All the configure.ac and specfile changes are unchanged from Thomas'
V3.
V3 re-ran "firewall-cmd --state" every time a new rule was added,
which was extremely inefficient. V4 uses VIR_ONCE_GLOBAL_INIT to set
up a one-time initialization function.
The VIR_ONCE_GLOBAL_INIT(x) macro references a static function called
vir(Ip|Eb)OnceInit(), which will then be called the first time that
the static function vir(Ip|Eb)TablesInitialize() is called (that
function is defined for you by the macro). This is
thread-safe, so there is no chance of any race.
IMPORTANT NOTE: I've left the VIR_DEBUG messages in these two init
functions (one for iptables, on for ebtables) as VIR_WARN so that I
don't have to turn on all the other debug message just to see
these. Even if this patch doesn't need any other modification, those
messages need to be changed to VIR_DEBUG before pushing.
This one-time initialization works well. However, I've encountered
problems with testing:
1) Whenever I have enabled the firewalld service, *all* attempts to
call firewall-cmd from within libvirtd end with firewall-cmd hanging
internally somewhere. This is *not* the case if firewall-cmd returns
non-0 in response to "firewall-cmd --state" (i.e. *that* command runs
and returns to libvirt successfully.)
2) If I start libvirtd while firewalld is stopped, then start
firewalld later, this triggers libvirtd to reload its iptables rules,
however it also spits out a *ton* of complaints about deletion failing
(I suppose because firewalld has nuked all of libvirt's rules). I
guess we need to suppress those messages (which is a more annoying
problem to fix than you might think, but that's another story).
3) I noticed a few times during this long line of errors that
firewalld made a complaint about "Resource Temporarily
unavailable. Having libvirtd access iptables commands directly at the
same time as firewalld is doing so is apparently problematic.
4) In general, I'm concerned about the "set it once and never change
it" method - if firewalld is disabled at libvirtd startup, causing
libvirtd to always use iptables/ebtables directly, this won't cause
*terrible* problems, but if libvirtd decides to use firewall-cmd and
firewalld is later disabled, libvirtd will not be able to recover.
This patch adds helper functions that enable us to use libssh2 in
conjunction with libvirt's virNetSockets for ssh transport instead of
spawning "ssh" client process.
This implemetation supports tunneled plaintext, keyboard-interactive,
private key, ssh agent based and null authentication. Libvirt's Auth
callback is used for interaction with the user. (Keyboard interactive
authentication, adding of host keys, private key passphrases). This
enables seamless integration into the application using libvirt. No
helpers as "ssh-askpass" are needed.
Reading and writing of OpenSSH style "known_hosts" files is supported.
Communication is done using SSH exec channel, where the user may specify
arbitrary command to be executed on the remote side and reads and writes
to/from stdin/out are sent through the ssh channel. Usage of stderr is
not (yet) supported.