virTypedParamsValidate currently uses an index based check to find
duplicate parameters. This check does not work. Consider the following
simple example:

We have only 2 keys
A  (multiples allowed)
B  (multiples NOT allowed)

We are given the following list of parameters to check:
A
A
B

If you work through the validation loop you will see that our last iteration
through the loop has i=2 and j=1. In this case, i > j and keys[j].value.i will
indicate that multiples are not allowed. Both conditionals are satisfied so
an incorrect error will be given: "parameter '%s' occurs multiple times"

This patch replaces the index based check with code that remembers
the name of the last parameter seen and only triggers the error case if
the current parameter name equals the last one. This works because the
list is sorted and duplicate parameters will be grouped together.

In reality, we hit this bug while using selective block migration to migrate
a guest with 5 disks. 5 was apparently just the right number to push i > j
and hit this bug.

virsh migrate --live guestname --copy-storage-all
              --migrate-disks vdb,vdc,vdd,vde,vdf
              qemu+ssh://dsthost/systemSigned-off-by: NJason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: NEric Farman <farman@linux.vnet.ibm.com>
(cherry picked from commit 0e570a6a)

We have macros for both positive and negative string matching.
Therefore there is no need to use !STREQ or !STRNEQ. At the same
time as we are dropping this, new syntax-check rule is
introduced to make sure we won't introduce it again.
Signed-off-by: NIshmanpreet Kaur Khera <khera.ishman@gmail.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The `virTypedParamsAddStringList' function provides interface to add a
NULL-terminated array of string values as a multi-value to the params.
Signed-off-by: NPavel Boldin <pboldin@mirantis.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Add multikey API:

 * virTypedParamsFilter that filters all the parameters with specified name.
 * virTypedParamsGetStringList that returns a list with all the values for
   specified name and string type.
Signed-off-by: NPavel Boldin <pboldin@mirantis.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The `virTypedParamsValidate' function now can be instructed to allow
multiple entries for some of the keys. For this flag the type with
the `VIR_TYPED_PARAM_MULTIPLE' flag.

Add unit tests for this new behaviour.
Signed-off-by: NPavel Boldin <pboldin@mirantis.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>