[libvirt] [PATCH 5/5] qemu: hook: Provide hook when restoring a domain save image
Jiri Denemark
jdenemar at redhat.com
Mon Sep 22 14:16:15 UTC 2014
On Wed, Sep 17, 2014 at 17:18:39 +0200, Peter Krempa wrote:
> ---
> docs/hooks.html.in | 11 ++++++++
> src/qemu/qemu_driver.c | 69 +++++++++++++++++++++++++++++++++++++++++++++-----
> src/util/virhook.c | 3 ++-
> src/util/virhook.h | 1 +
> 4 files changed, 76 insertions(+), 8 deletions(-)
>
> diff --git a/docs/hooks.html.in b/docs/hooks.html.in
> index 07b9d49..265dbb7 100644
> --- a/docs/hooks.html.in
> +++ b/docs/hooks.html.in
> @@ -177,6 +177,17 @@
> script returns failure or the output XML is not valid, incoming
> migration will be canceled. This hook may be used, e.g., to change
> location of disk images for incoming domains.</li>
> + <li><span class="since">Since 1.2.9</span>, the qemu hook script is
> + also called when restoring a saved image either via the API or
> + automatically when restoring a managed save machine. It is called
> + as: <pre>/etc/libvirt/hooks/qemu guest_name restore begin -</pre>
> + with domain XML sent to standard input of the script. In this case,
> + the script acts as a filter and is supposed to modify the domain
> + XML and print it out on its standard output. Empty output is
> + identical to copying the input XML without changing it. In case the
> + script returns failure or the output XML is not valid, restore of the
> + image will be aborted. This hook may be used, e.g., to change
> + location of disk images for incoming domains.</li>
Copy&paste? "incoming domains" does not make a lot of sense in case of
restore :-)
> <li><span class="since">Since 0.9.13</span>, the qemu hook script
> is also called when the libvirtd daemon restarts and reconnects
> to previously running QEMU processes. If the script fails, the
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 1d82e93..2dd2e48 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -5636,20 +5636,23 @@ qemuDomainRestoreFlags(virConnectPtr conn,
> unsigned int flags)
> {
> virQEMUDriverPtr driver = conn->privateData;
> + qemuDomainObjPrivatePtr priv = NULL;
> virDomainDefPtr def = NULL;
> - virDomainDefPtr newdef = NULL;
> virDomainObjPtr vm = NULL;
> + char *xml = NULL;
> + char *xmlout = NULL;
> int fd = -1;
> int ret = -1;
> virQEMUSaveHeader header;
> virFileWrapperFdPtr wrapperFd = NULL;
> + bool hook_taint = false;
>
> virCheckFlags(VIR_DOMAIN_SAVE_BYPASS_CACHE |
> VIR_DOMAIN_SAVE_RUNNING |
> VIR_DOMAIN_SAVE_PAUSED, -1);
>
>
> - fd = qemuDomainSaveImageOpen(driver, path, &def, &header, NULL,
> + fd = qemuDomainSaveImageOpen(driver, path, &def, &header, &xml,
> (flags & VIR_DOMAIN_SAVE_BYPASS_CACHE) != 0,
> &wrapperFd, false, false);
> if (fd < 0)
> @@ -5658,12 +5661,29 @@ qemuDomainRestoreFlags(virConnectPtr conn,
> if (virDomainRestoreFlagsEnsureACL(conn, def) < 0)
> goto cleanup;
>
> - if (dxml) {
> - if (!(newdef = qemuDomainSaveImageUpdateDef(driver, def, dxml)))
> + if (virHookPresent(VIR_HOOK_DRIVER_QEMU)) {
> + int hookret;
> +
> + if ((hookret = virHookCall(VIR_HOOK_DRIVER_QEMU, def->name,
> + VIR_HOOK_QEMU_OP_RESTORE,
> + VIR_HOOK_SUBOP_BEGIN,
> + NULL,
> + dxml ? dxml : xml,
> + &xmlout)) < 0)
> goto cleanup;
>
> - virDomainDefFree(def);
> - def = newdef;
> + if (hookret == 0 && xmlout) {
> + virDomainDefPtr tmp;
> +
> + VIR_DEBUG("Using hook-filtered domain XML: %s", xmlout);
> +
> + if (!(tmp = qemuDomainSaveImageUpdateDef(driver, def, xmlout)))
> + goto cleanup;
> +
> + virDomainDefFree(def);
> + def = tmp;
> + hook_taint = true;
> + }
I think you wanted to write this in a bit different way... This way dxml
is ignored when the hook is not present.
> }
>
> if (!(vm = virDomainObjListAdd(driver->domains, def,
...
Jirka
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