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>

I find it more readable that way.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

Similarly to gethostbyname3(), the @addr must be freed on return
from the function.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

The findLease() function allocates @addr array iff no error
occurred and at least one satisfactory record was found.
Therefore, there is no need to call free() if findLease() failed,
or did not find any records as addr == NULL.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NErik Skultety <eskultet@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>

The NSS module has a compile time option which when enabled makes
ERROR() and DEBUG() print messages onto stderr. But now that the
module no longer links with libvirt, we need to include stdio.h
and define NULLSTR().
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 conversion to drop gnulib in the previous patch:

  commit 8242ce4f
  Author: Daniel P. Berrangé <berrange@redhat.com>
  Date:   Thu Aug 8 10:23:26 2019 +0100

    tools: avoid accidentally using files from gnulib

Missed a few conversions needed for FreeBSD. In particular
netdb.h doesn't pull in sys/socket.h or netinet/in.h
Signed-off-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>

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>

The .macs file is currently loaded using the virMacMap class,
which in turn uses the virJSON parsing code. This pulls in a
heap of libvirt code (logging, hash tables, objects, 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>

Build a list of mac addresses immediately, so that later code
searching for leases can be simplified and avoid needing to
use the virMacMap object.
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 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 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>

Ideally, a software that's translating domain names would iterate
over all addresses the NSS returned, but some software does not
bother (e.g. ping). What happens is that for instance when
installing a guest, it's assigned one IP address but once it's
installed and rebooted it gets a different IP address (because
client ID used for the first DHCP traffic when installing the
guest was generated dynamically and never saved so after reboot
the guest generated new ID which resulted in different IP address
to be assigned). This results in 'ping $domain' not working
properly as it still pings the old IP address. Well, it might -
NSS plugin does not guarantee any order of addresses.

To resolve this problem, we can sort the array just before
returning it to the caller (ping) so that the newer IP addresses
come before older ones.
Reported-by: NAndrea Bolognani <abologna@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

In the nss plugin we have ERROR() macro which by default does
nothing. However, at compile time it can be made to report errors
(this is useful for debugging because by nature of NSS debugging
is hard). Anyway, the appendAddr() function uses @name (which
contains name the caller wants us to resolve) for error
reporting. But the caller findLeaseInJSON() is not passing it.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

Signed-off-by: NJonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>
Signed-off-by: NJán Tomko <jtomko@redhat.com>

When dealing with internal paths we don't need to worry about
whether or not suffixes are lowercase since we have full control
over them, which means we can avoid performing case-insensitive
string comparisons.
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>
ACKed-by: NPeter Krempa <pkrempa@redhat.com>

Despite its name, this is really just a general-purpose string
manipulation function, so it should be moved to the virstring
module and renamed accordingly.

In addition to the obvious s/File/String/, also tweak the name
to make it clear that the presence of the suffix is verified
using case-insensitive comparison.

A few trivial whitespace changes are squashed in.
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>
ACKed-by: NPeter Krempa <pkrempa@redhat.com>

Require that all headers are guarded by a symbol named

  LIBVIRT_$FILENAME

where $FILENAME is the uppercased filename, with all characters
outside a-z changed into '_'.

Note we do not use a leading __ because that is technically a
namespace reserved for the toolchain.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

In many files there are header comments that contain an Author:
statement, supposedly reflecting who originally wrote the code.
In a large collaborative project like libvirt, any non-trivial
file will have been modified by a large number of different
contributors. IOW, the Author: comments are quickly out of date,
omitting people who have made significant contribitions.

In some places Author: lines have been added despite the person
merely being responsible for creating the file by moving existing
code out of another file. IOW, the Author: lines give an incorrect
record of authorship.

With this all in mind, the comments are useless as a means to identify
who to talk to about code in a particular file. Contributors will always
be better off using 'git log' and 'git blame' if they need to  find the
author of a particular bit of code.

This commit thus deletes all Author: comments from the source and adds
a rule to prevent them reappearing.

The Copyright headers are similarly misleading and inaccurate, however,
we cannot delete these as they have legal meaning, despite being largely
inaccurate. In addition only the copyright holder is permitted to change
their respective copyright statement.
Reviewed-by: NErik Skultety <eskultet@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

Rather than have virJSONValueArraySize return a -1 when the input
is not an array and then splat an error message, let's check for
an array before calling and then change the return to be a size_t
instead of ssize_t.

That means using the helper virJSONValueIsArray as well as using a
more generic error message such as "Malformed <something> array".
In some cases we can remove stack variables and when we cannot,
those variables should be size_t not ssize_t. Alter a few references
of if (!value) to be if (value == 0) instead as well.

Some callers can already assume an array is being worked on based
on the previous call, so there's less to do.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Right-aligning backslashes when defining macros or using complex
commands in Makefiles looks cute, but as soon as any changes is
required to the code you end up with either distractingly broken
alignment or unnecessarily big diffs where most of the changes
are just pushing all backslashes a few characters to one side.

Generated using

  $ git grep -El '[[:blank:]][[:blank:]]\\$' | \
    grep -E '*\.([chx]|am|mk)$$' | \
    while read f; do \
      sed -Ei 's/[[:blank:]]*[[:blank:]]\\$/ \\/g' "$f"; \
    done
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>

In my previous commit of b1d87f9a I've made a typo breaking
the FreeBSD build. s/ipAaddr/ipAddr/
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

In aiforaf() (which exists only when building for BSD) the
@ipAddr may be leaked.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The recent deprecation in glibc (commit b76e065991ec) means the
module will fail to build entirely:

  nss/libvirt_nss.c: In function '_nss_libvirt_gethostbyname_r':
  nss/libvirt_nss.c:363:13: error: RES_USE_INET6 is deprecated [-Werror]
     int af = ((_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET);
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This resolver option was removed shortly after being introduced,
and application using it are already broken anyway.

If the 'nleases < 0' on return, then the subsequent call to
findLeaseInJSON will not produce the expected results (passed
in as a size_t, but nleases is a ssize_t).  So check if the
returned value < 0 and if so, goto cleanup.

Found by Coverity as a NEGATIVE_RETURNS event

So far the NSS module looks up only hostnames as provided by
guests themselves. However, there are some cases where this is
not enough: e.g. when there's a fresh new guest being installed
(with some generic hostname) say from a live ISO image; or some
(older) systems don't advertise their hostname in DHCP
transactions at all.
In cases like that it would be helpful if we translate domain
name as seen by libvirt too so that users can:

  # virsh start $dom && ssh $dom

In order to achieve that new libvirt-guest module is introduced,
while older libvirt module maintains its current behaviour (that
is translating guest provided names into IP addresses).
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The part of the code that iterates over an array of JSON values
is going to be re-used. Instead of copying it over, move it to a
separate function.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The part of the code that appends found IP address into a list is
going to be re-used. Instead of copying it over, move it to a
separate function.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The name of the exported functions for an NSS module is quite
fixed, it is derived from the module name:

  _nss_$module_$function

Since we will create another NSS module with very similar
implementation we might as well generate the function names at
the compile time.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The NSS module shouldn't rely on custom leases database to not have
entries for leases which have expired.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>