Before we rewrote nss plugin so that it doesn't use libvirt's
internal functions it used virLeaseReadCustomLeaseFile() to parse
.status files. After the rewrite it's using read() + yajl_parse()
+ yajl_complete_parse(). There's one catch though,
virLeaseReadCustomLeaseFile() skipped over empty files.

An empty .status file is created when a network is started. This
is because we configure dnsmasq to use our leasehelper. So the
first thing it does it calls it as follows:

  DNSMASQ_INTERFACE=virbr0 /usr/libexec/libvirt_leaseshelper init

which causes the leasehelper to create empty virbr0.status file.
If there is only one libvirt network then that is no problem -
there are no other .status files to parse anyway. But if there
are two or more networks then the first empty .status file causes
whole parsing process and subsequently the whole name lookup
process to fail.

Fixes: v5.7.0-rc1~343
Reported-by: NPavel Hrdina <phrdina@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

When parsing leases file, appendAddr() is called to append parsed
tuple (address, expiry time, family) into an array. Whilst doing
so, the array is searched for possible duplicate. This is done by
comparing each item of the array by passed @family: if @family is
AF_INET then the item is viewed as IPv4 address. Similarly, if
@family is AF_INET6 then the item is viewed as IPv6 address. This
is not exactly right - the array can contain addresses of both
families and thus the address family of each item of the array
must be considered.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

If yajl_parse() fails, we try to print an error message. For
that, yajl_get_error() is used. However, its documentation say
that caller is also responsible for freeing the memory it
allocates by using yajl_free_error().
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

Due to latest rewrite of NSS module, we are doing yajl parsing
ourselves. This means, we had to introduce couple of callback
that yajl calls. According to its documentation, a callback can
cancel parsing if it returns a zero value. Well, we do just that
in the string callback (findLeasesParserString()). If the JSON
file we are parsing contains a key that we are not interested in,
zero is returned meaning stop all parsing. This is not correct,
because the JSON file can contain some other keys which are not
harmful for our address translation (e.g. 'client-id').
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

The AM_CPPFLAGS setting includes the gnulib headers, which
means we can get some replacement functions defined. Since
virt-login-shell and the NSS module intentionally don't link
to gnulib, these replacement functions causes link failures.

This was seen cross-compiling on Debian for example:

virt-login-shell.o: In function `main':
/builds/libvirt/libvirt/build/tools/../../tools/virt-login-shell.c:81: undefined reference to `rpl_strerror'
/builds/libvirt/libvirt/build/tools/../../tools/virt-login-shell.c:66: undefined reference to `rpl_strerror'
/builds/libvirt/libvirt/build/tools/../../tools/virt-login-shell.c:75: undefined reference to `rpl_strerror'

The only way to avoid these replacement gnulib headers is
to drop the -Ignulib/lib flags. We do still want to use
gnulib for configmake.h and intprops.h, but those can be
included via their full path.

We must also stop using internal.h, since that expects
-Ignulib/lib to be on the include path in order to resolve
the verify.h header.
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

Use the plain libc APIs to avoid a dependancy on the main libvirt
code from the nss module.
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

Use the plain libc socket APIs to avoid a dependancy on the main
libvirt code from the nss module.
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

The .leases file is currently loaded using the virLease class,
which in turn uses the virJSON parsing code. This pulls in a
heap of libvirt code (logging, hash tables, etc) which we do
not wish to depend on.

This uses the yajl parser code directly, so the only dep is
yajl and plain libc functions.
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>