From daa6ee36e4fc3e17119231f110b4de770ffd2b6c Mon Sep 17 00:00:00 2001

Message-Id: <daa6ee36e4fc3e17119231f110b4de770ffd2b6c@dist-git>

From: Peter Krempa <pkrempa@redhat.com>

Date: Mon, 22 Sep 2014 17:52:40 +0200

Subject: [PATCH] qemu: hook: Provide hook when restoring a domain save image

https://bugzilla.redhat.com/show_bug.cgi?id=1142693

(cherry picked from commit 4f3c2e39e5c898c533ddf58b62b452a674df794d)

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 docs/hooks.html.in     | 11 ++++++++

 src/qemu/qemu_driver.c | 70 +++++++++++++++++++++++++++++++++++++++++++++-----

 src/util/virhook.c     |  3 ++-

 src/util/virhook.h     |  1 +

 4 files changed, 78 insertions(+), 7 deletions(-)

diff --git a/docs/hooks.html.in b/docs/hooks.html.in

index 07b9d49..1aae00c 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.

+      
Since 1.2.9, 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: 
/etc/libvirt/hooks/qemu guest_name restore begin -

+        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 restored domains.

       
Since 0.9.13, 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 580ac17..8f655e5 100644

--- a/src/qemu/qemu_driver.c

+++ b/src/qemu/qemu_driver.c

@@ -5643,20 +5643,24 @@ 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;

+    const char *newxml = dxml;

     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)

@@ -5665,12 +5669,31 @@ 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;

+

+        if (hookret == 0 && xmlout) {

+            VIR_DEBUG("Using hook-filtered domain XML: %s", xmlout);

+            hook_taint = true;

+            newxml = xmlout;

+        }

+    }

+

+    if (newxml) {

+        virDomainDefPtr tmp;

+        if (!(tmp = qemuDomainSaveImageUpdateDef(driver, def, newxml)))

             goto cleanup;

         virDomainDefFree(def);

-        def = newdef;

+        def = tmp;

     }

     if (!(vm = virDomainObjListAdd(driver->domains, def,

@@ -5686,6 +5709,11 @@ qemuDomainRestoreFlags(virConnectPtr conn,

     else if (flags & VIR_DOMAIN_SAVE_PAUSED)

         header.was_running = 0;

+    if (hook_taint) {

+        priv = vm->privateData;

+        priv->hookRun = true;

+    }

+

     if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)

         goto cleanup;

@@ -5704,6 +5732,8 @@ qemuDomainRestoreFlags(virConnectPtr conn,

  cleanup:

     virDomainDefFree(def);

     VIR_FORCE_CLOSE(fd);

+    VIR_FREE(xml);

+    VIR_FREE(xmlout);

     virFileWrapperFdFree(wrapperFd);

     if (vm)

         virObjectUnlock(vm);

@@ -5841,12 +5871,15 @@ qemuDomainObjRestore(virConnectPtr conn,

                      bool bypass_cache)

 {

     virDomainDefPtr def = NULL;

+    qemuDomainObjPrivatePtr priv = vm->privateData;

     int fd = -1;

     int ret = -1;

+    char *xml = NULL;

+    char *xmlout = NULL;

     virQEMUSaveHeader header;

     virFileWrapperFdPtr wrapperFd = NULL;

-    fd = qemuDomainSaveImageOpen(driver, path, &def, &header, NULL,

+    fd = qemuDomainSaveImageOpen(driver, path, &def, &header, &xml,

                                  bypass_cache, &wrapperFd, false, true);

     if (fd < 0) {

         if (fd == -3)

@@ -5854,6 +5887,29 @@ qemuDomainObjRestore(virConnectPtr conn,

         goto cleanup;

     }

+    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, xml, &xmlout)) < 0)

+            goto cleanup;

+

+        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;

+            priv->hookRun = true;

+        }

+    }

+

     if (STRNEQ(vm->def->name, def->name) ||

         memcmp(vm->def->uuid, def->uuid, VIR_UUID_BUFLEN)) {

         char vm_uuidstr[VIR_UUID_STRING_BUFLEN];

@@ -5877,6 +5933,8 @@ qemuDomainObjRestore(virConnectPtr conn,

         VIR_WARN("Failed to close %s", path);

  cleanup:

+    VIR_FREE(xml);

+    VIR_FREE(xmlout);

     virDomainDefFree(def);

     VIR_FORCE_CLOSE(fd);

     virFileWrapperFdFree(wrapperFd);

diff --git a/src/util/virhook.c b/src/util/virhook.c

index ac7b40f..25d0783 100644

--- a/src/util/virhook.c

+++ b/src/util/virhook.c

@@ -77,7 +77,8 @@ VIR_ENUM_IMPL(virHookQemuOp, VIR_HOOK_QEMU_OP_LAST,

               "migrate",

               "started",

               "reconnect",

-              "attach")

+              "attach",

+              "restore")

 VIR_ENUM_IMPL(virHookLxcOp, VIR_HOOK_LXC_OP_LAST,

               "start",

diff --git a/src/util/virhook.h b/src/util/virhook.h

index 5bc0a5f..550ef84 100644

--- a/src/util/virhook.h

+++ b/src/util/virhook.h

@@ -60,6 +60,7 @@ typedef enum {

     VIR_HOOK_QEMU_OP_STARTED,          /* domain has started */

     VIR_HOOK_QEMU_OP_RECONNECT,        /* domain is being reconnected by libvirt */

     VIR_HOOK_QEMU_OP_ATTACH,           /* domain is being attached to be libvirt */

+    VIR_HOOK_QEMU_OP_RESTORE,          /* domain is being restored */

     VIR_HOOK_QEMU_OP_LAST,

 } virHookQemuOpType;

-- 

2.1.1