Now that we've activated two hacks to prevent unloading of modules,
there is no point passing back a pointer to the loaded library handle.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

The storage driver backends are serving the public storage pools API,
while the storage file backends are serving the internal QEMU driver and
/ or libvirt utility code.

To prep for moving this storage file backend framework into the utility
code, split out the backend definitions.
Signed-off-by: NDaniel P. Berrange <berrange@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>

Driver modules proved to be reliable for a long time. Since support for
not building modules complicates the code and makefiles drop it.
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>

When registering a storage poll backend, the code would use
virStorageTypeToString instead of virStoragePoolTypeToString. The
following message would be logged:

virDriverLoadModuleFunc:71 : Lookup function 'virStorageBackendSCSIRegister'
virStorageBackendRegister:174 : Registering storage backend '(null)'

Add a new storage driver registration function that will force the
backend code to fail if any of the storage backend modules can't be
loaded. This will make sure that they work and are present.

If driver modules are enabled turn storage driver backends into
dynamically loadable objects. This will allow greater modularity for
binary distributions, where heavyweight dependencies as rbd and gluster
can be avoided by selecting only a subset of drivers if the rest is not
necessary.

The storage modules are installed into 'LIBDIR/libvirt/storage-backend/'
and users can override the location by using
'LIBVIRT_STORAGE_BACKEND_DIR' environment variable.

rpm based distros will at this point install all the backends when
libvirt-daemon-driver-storage package is installed.

Add APIs that allow to dynamically register driver backends so that the
list of available drivers does not need to be known during compile time.

This will allow us to modularize the storage driver on runtime.

Added general definitions for vstorage pool backend including
the build options to add --with-storage-vstorage checking.
In order to use vstorage as a backend for a storage pool
vstorage tools (vstorage and vstorage-mount) need to be installed.
Signed-off-by: NOlga Krishtal <okrishtal@virtuozzo.com>

The file became a garbage dump for all kinds of utility functions over
time. Move them to a separate file so that the files can become a clean
interface for the storage backends.

The storage driver helper functions that deal with parted were put into
the disk backend code but are used commonly across.

If the voldef type is VIR_STORAGE_VOL_BLOCK, then as long as the
format is known, let's allow the probe to happen - gets a truer value
and the same probe/update would be allowed for the same volume defined
in a domain.

For volume processing in virStorageBackendUpdateVolTargetInfo to get
the capacity commit id 'a760ba3a' added the ability to probe a volume
that didn't list a target format. Unfortunately, the code used the
virStorageSource  (e.g. target->type - virStorageType) rather than
virStorageVolDef (e.g. vol->type - virStorageVolType) in order to
make the comparison. As it turns out target->type for a volume is
not filled in at all for a voldef as the code relies on vol->type.
Ironically the result is that only VIR_STORAGE_VOL_BLOCK's would get
their capacity updated.

This patch will adjust the code to check the "vol->type" field instead
as an argument. This way for a voldef, the correct comparison is made.

Additionally for a backingStore, the 'type' field is never filled in;
however, since we know that the provided path is a location at which
the backing store can be accessed on the local filesystem thus just
pass VIR_STORAGE_VOL_FILE in order to satisfy the adjusted voltype
check. Whether it's a FILE or a BLOCK only matters if we're trying to
get more data based on the target->format.

The tool is used for pool discovery. Since we call an external binary we
don't really need to compile out the code that uses it. We can check
whether it exists at runtime.

In commit 4090e153 we went back from reporting no errors if no storage
pools were found on a given host to reporting a bad error. And only in
cases when gluster was not installed.

Report a less bad error in case there are no volumes. Also report the
error when gluster is installed but no volumes were found, since
virStorageBackendFindGlusterPoolSources would return success in that
case.

For case VIR_STORAGE_BLKID_PROBE_DIFFERENT, clean up the message to
avoid using the virsh like --overwrite syntax. Additionally provide
a different error message when not writing the label to avoid confusion.

Rather than special casing the VIR_STORAGE_BLKID_PROBE_UNKNOWN after
calling virStorageBackendBLKIDFindPart, just allow the switch statement
handle setting ret = -2.

If neither BLKID or PARTED is available and we're not writing, then
just return 0 which allows the underlying storage pool to generate
a failure. If both are unavailable and we're writing, then generate
a more generic error message.

Commit id 'a48c674f' caused problems for systems without PARTED installed.

So move the PARTED probing code back to storage_backend_disk.c and create
a shim within storage_backend.c to call it if WITH_STORAGE_DISK is true;
otherwise, just return -1 with the error.

Currently as long as the disk is formatted using a known parted format
type, the algorithm is happy to continue. However, that leaves a scenario
whereby a disk formatted using "pc98" could be used by a pool that's defined
using "dvh" (or vice versa). Alter the check to be match and different
and adjust the caller.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Rather than have the Disk code having to use PARTED to determine if
there's something on the device, let's use the virStorageBackendDeviceProbe.
and only fallback to the PARTED probing if the BLKID code isn't built in.

This will also provide a mechanism for the other current caller (File
System Backend) to utilize a PARTED parsing algorithm in the event that
BLKID isn't built in to at least see if *something* exists on the disk
before blindly trying to use. The PARTED error checking will not find
file system types, but if there is a partition table set on the device,
it will at least cause a failure.

Move virStorageBackendDiskValidLabel and virStorageBackendDiskFindLabel
to storage_backend and rename/rework the code to fit the new model.

Update the virsh.pod description to provide a more generic description
of the process since we could now use either blkid or parted to find
data on the target device.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

It's possible that the API could be called from a startup path in
order to check whether the label on the device matches what our
format is. In order to handle that condition, add a 'writelabel'
boolean to the API in order to indicate whether a write or just
read is about to happen.

This alters two "error" conditions that would care about knowing.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

A device may be formatted using some sort of disk partition format type.
We can check that using the blkid_ API's as well - so alter the logic to
allow checking the device for both a filesystem and a disk partition.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

https://bugzilla.redhat.com/show_bug.cgi?id=1363586

Commit id '27758859' introduced the "NO_OVERWRITE" flag check for
file system backends; however, the implementation, documentation,
and algorithm was inconsistent. For the "flag" description for the
API the flag was described as "Do not overwrite existing pool";
however, within the storage backend code the flag is described
as "it probes to determine if filesystem already exists on the
target device, renurning an error if exists".

The code itself was implemented using the paradigm to set up the
superblock probe by creating a filter that would cause the code
to only search for the provided format type. If that type wasn't
found, then the algorithm would return success allowing the caller
to format the device. If the format type already existed on the
device, then the code would fail indicating that the a filesystem
of the same type existed on the device.

The result is that if someone had a file system of one type on the
device, it was possible to overwrite it if a different format type
was specified in updated XML effectively trashing whatever was on
the device already.

This patch alters what NO_OVERWRITE does for a file system backend
to be more realistic and consistent with what should be expected when
the caller requests to not overwrite the data on the disk.

Rather than filter results based on the expected format type, the
code will allow success/failure be determined solely on whether the
blkid_do_probe calls finds some known format on the device. This
adjustment also allows removal of the virStoragePoolProbeResult
enum that was under utilized.

If it does find a formatted file system different errors will be
generated indicating a file system of a specific type already exists
or a file system of some other type already exists.

In the original virsh support commit id 'ddcd5674', the description
for '--no-overwrite' within the 'pool-build' command help output
has an ambiguous "of this type" included in the short description.
Compared to the longer description within the "Build a given pool."
section of the virsh.pod file it's more apparent that the meaning
of this flag would cause failure if a probe of the target already
has a filesystem.

So this patch also modifies the short description to just be the
antecedent of the 'overwrite' flag, which matches the API description.
This patch also modifies the grammar in virsh.pod for no-overwrite
as well as reworking the paragraph formats to make it easier to read.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Rename virStorageBackendFileSystemProbe and to virStorageBackendBLKIDFindFS
and move to the more common storage_backend module.

Create a shim virStorageBackendDeviceIsEmpty which will make the call
to the virStorageBackendBLKIDFindFS and check the return value.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

The public virSecret object has a single "usage_id" field
but the virSecretDef object has a different 'char *' field
for each usage type, but the code all assumes every usage
type has a corresponding single string. Get rid of the
pointless union in virSecretDef and just use "usage_id"
everywhere. This doesn't impact public XML format, only
the internal handling.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Instead of having duplicated code in qemuStorageLimitsRefresh and
virStorageBackendUpdateVolTargetInfo to get capacity specific data
about the storage backing source or volume -- create a common API
to handle the details for both.

As a side effect, virStorageFileProbeFormatFromBuf returns to being
a local/static helper to virstoragefile.c

For the QEMU code - if the probe is done, then the format is saved so
as to avoid future such probes.

For the storage backend code, there is no need to deal with the probe
since we cannot call the new API if target->format == NONE.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Instead of having duplicated code in qemuStorageLimitsRefresh and
virStorageBackendUpdateVolTargetInfoFD to fill in the storage backing
source or volume allocation, capacity, and physical values - create a
common API that will handle the details for both.

The common API will fill in "default" capacity values as well - although
those more than likely will be overridden by subsequent code. Having just
one place to make the determination of what the values should be will
make things be more consistent.

For the QEMU code - the data filled in will be for inactive domains
for the GetBlockInfo and DomainGetStatsOneBlock API's. For the storage
backend code - the data will be filled in during the volume updates.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

There was a missing check for vol->target.encryption being NULL
at one particular place (modified by commit a48c7141) which caused a crash
when user attempted to create a raw volume using a non-raw file volume as
source.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1363636Signed-off-by: NErik Skultety <eskultet@redhat.com>

Let's cleanly differentiate what wiping a volume does for ploop and
other volumes so it's more readable what is done for each one instead of
branching out multiple times in different parts of the same function.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

Some functions use volume specification merely to use the target path
from it.  Let's change it to pass the path only so that it can be used
for other files than just volumes.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

This is done in order to call them in next patches from each other and
definitions would be missing otherwise.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

The current LUKS support has a "luks" volume type which has
a "luks" encryption format.

This partially makes sense if you consider the QEMU shorthand
syntax only requires you to specify a format=luks, and it'll
automagically uses "raw" as the next level driver. QEMU will
however let you override the "raw" with any other driver it
supports (vmdk, qcow, rbd, iscsi, etc, etc)

IOW the intention though is that the "luks" encryption format
is applied to all disk formats (whether raw, qcow2, rbd, gluster
or whatever). As such it doesn't make much sense for libvirt
to say the volume type is "luks" - we should be saying that it
is a "raw" file, but with "luks" encryption applied.

IOW, when creating a storage volume we should use this XML

  <volume>
    <name>demo.raw</name>
    <capacity>5368709120</capacity>
    <target>
      <format type='raw'/>
      <encryption format='luks'>
        <secret type='passphrase' uuid='0a81f5b2-8403-7b23-c8d6-21ccd2f80d6f'/>
      </encryption>
    </target>
  </volume>

and when configuring a guest disk we should use

  <disk type='file' device='disk'>
    <driver name='qemu' type='raw'/>
    <source file='/home/berrange/VirtualMachines/demo.raw'/>
    <target dev='sda' bus='scsi'/>
    <encryption format='luks'>
      <secret type='passphrase' uuid='0a81f5b2-8403-7b23-c8d6-21ccd2f80d6f'/>
    </encryption>
  </disk>

This commit thus removes the "luks" storage volume type added
in

  commit 318ebb36
  Author: John Ferlan <jferlan@redhat.com>
  Date:   Tue Jun 21 12:59:54 2016 -0400

    util: Add 'luks' to the FileTypeInfo

The storage file probing code is modified so that it can probe
the actual encryption formats explicitly, rather than merely
probing existance of encryption and letting the storage driver
guess the format.

The rest of the code is then adapted to deal with
VIR_STORAGE_FILE_RAW w/ VIR_STORAGE_ENCRYPTION_FORMAT_LUKS
instead of just VIR_STORAGE_FILE_LUKS.

The commit mentioned above was included in libvirt v2.0.0.
So when querying volume XML this will be a change in behaviour
vs the 2.0.0 release - it'll report 'raw' instead of 'luks'
for the volume format, but still report 'luks' for encryption
format.  I think this change is OK because the storage driver
did not include any support for creating volumes, nor starting
guets with luks volumes in v2.0.0 - that only since then.
Clearly if we change this we must do it before v2.1.0 though.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Commit id '5e46d7d6' did not take into account that usage of a luks
volume will require usage of the master key encrypted passphrase for
a QEMU environment.  So rather than allow creation of something that
won't be usable, just fail the creation.

virStorageBackendCreateQemuImgCheckEncryption didn't return -1 if there
were no secrets.

Partially resolves:
https://bugzilla.redhat.com/show_bug.cgi?id=1301021

If the volume xml was looking to create a luks volume take the necessary
steps in order to make that happen.

The processing will be:
 1. create a temporary file (virStorageBackendCreateQemuImgSecretPath)
   1a. use the storage driver state dir path that uses the pool and
       volume name as a base.

 2. create a secret object (virStorageBackendCreateQemuImgSecretObject)
   2a. use an alias combinding the volume name and "_luks0"
   2b. add the file to the object

 3. create/add luks options to the commandline (virQEMUBuildLuksOpts)
   3a. at the very least a "key-secret=%s" using the secret object alias
   3b. if found in the XML the various "cipher" and "ivgen" options
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

The modification of .volWipe callback wipes ploop volume using one of
given wiping algorithm: dod, nnsa, etc.
However, in case of ploop volume we need to reinitialize root.hds and DiskDescriptor.xml.

v2:
- added check on ploop tools presens
- virCommandAddArgFormat changed to virCommandAddArg
Signed-off-by: NOlga Krishtal <okrishtal@virtuozzo.com>

Add parse and format of the luks/passphrase secret including tests for
volume XML parsing.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

In order to use more common code and set up for a future type, modify the
encryption secret to allow the "usage" attribute or the "uuid" attribute
to define the secret. The "usage" in the case of a volume secret would be
the path to the volume as dictated by the backwards compatibility brought
on by virStorageGenerateQcowEncryption where it set up the usage field as
the vol->target.path and didn't allow someone to provide it. This carries
into virSecretObjListFindByUsageLocked which takes the secret usage attribute
value from from the domain disk definition and compares it against the
usage type from the secret definition. Since none of the code dealing
with qcow/qcow2 encryption secrets uses usage for lookup, it's a mostly
cosmetic change. The real usage comes in a future path where the encryption
is expanded to be a luks volume and the secret will allow definition of
the usage field.

This code will make use of the virSecretLookup{Parse|Format}Secret common code.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Remove all the remaining usage of opendir.