[PATCH 2/3] lib: Repurpose virDomainSaveParams() with no VIR_DOMAIN_SAVE_PARAM_FILE

[Michal Privoznik <mprivozn@xxxxxxxxxx>]

When no VIR_DOMAIN_SAVE_PARAM_FILE typed param is set when
calling virDomainSaveParams() then in turn virQEMUFileOpenAs()
tries to open a NULL path.

We have two options now:
1) require the typed param, which in turn may be promoted to a
   regular argument, or

2) use this opportunity to make the API behave like
   virDomainManagedSave() and use typed params to pass extra
   arguments, instead of having to invent new managed save API
   with typed params.

Let's go with option 2, as it is more future proof.

Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx>
---
 src/libvirt-domain.c   |  2 ++
 src/qemu/qemu_driver.c | 33 ++++++++++++++++++++-------------
 2 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index d1d62daa71..208c2438fe 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -1007,6 +1007,8 @@ virDomainSaveFlags(virDomainPtr domain, const char *to,
  * @flags: bitwise-OR of virDomainSaveRestoreFlags
  *
  * This method extends virDomainSaveFlags by adding parameters.
+ * If VIR_DOMAIN_SAVE_PARAM_FILE is not provided then a managed save is
+ * performed (see virDomainManagedSave).
  *
  * Returns 0 in case of success and -1 in case of failure.
  *
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 7d8c7176d9..0b31c73bb9 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -2772,6 +2772,7 @@ qemuDomainManagedSavePath(virQEMUDriver *driver, virDomainObj *vm)
 static int
 qemuDomainManagedSaveHelper(virQEMUDriver *driver,
                             virDomainObj *vm,
+                            const char *dxml,
                             unsigned int flags)
 {
     g_autoptr(virQEMUDriverConfig) cfg = NULL;
@@ -2799,7 +2800,7 @@ qemuDomainManagedSaveHelper(virQEMUDriver *driver,
     VIR_INFO("Saving state of domain '%s' to '%s'", vm->def->name, path);
 
     if (qemuDomainSaveInternal(driver, vm, path, compressed,
-                                 compressor, NULL, flags) < 0)
+                                 compressor, dxml, flags) < 0)
         return -1;
 
     vm->hasManagedSave = true;
@@ -2853,17 +2854,18 @@ qemuDomainSave(virDomainPtr dom, const char *path)
 
 static int
 qemuDomainSaveParams(virDomainPtr dom,
-                     virTypedParameterPtr params, int nparams,
+                     virTypedParameterPtr params,
+                     int nparams,
                      unsigned int flags)
 {
+    virQEMUDriver *driver = dom->conn->privateData;
+    g_autoptr(virQEMUDriverConfig) cfg = NULL;
+    virDomainObj *vm = NULL;
+    g_autoptr(virCommand) compressor = NULL;
     const char *to = NULL;
     const char *dxml = NULL;
-    virQEMUDriver *driver = dom->conn->privateData;
     int compressed;
-    g_autoptr(virCommand) compressor = NULL;
     int ret = -1;
-    virDomainObj *vm = NULL;
-    g_autoptr(virQEMUDriverConfig) cfg = NULL;
 
     virCheckFlags(VIR_DOMAIN_SAVE_BYPASS_CACHE |
                   VIR_DOMAIN_SAVE_RUNNING |
@@ -2884,18 +2886,23 @@ qemuDomainSaveParams(virDomainPtr dom,
                                 VIR_DOMAIN_SAVE_PARAM_DXML, &dxml) < 0)
         return -1;
 
-    cfg = virQEMUDriverGetConfig(driver);
-    if ((compressed = qemuSaveImageGetCompressionProgram(cfg->saveImageFormat,
-                                                         &compressor,
-                                                         "save", false)) < 0)
-        goto cleanup;
-
     if (!(vm = qemuDomainObjFromDomain(dom)))
         goto cleanup;
 
     if (virDomainSaveParamsEnsureACL(dom->conn, vm->def) < 0)
         goto cleanup;
 
+    if (!to) {
+        /* If no save path was provided then this behaves as managed save. */
+        return qemuDomainManagedSaveHelper(driver, vm, dxml, flags);
+    }
+
+    cfg = virQEMUDriverGetConfig(driver);
+    if ((compressed = qemuSaveImageGetCompressionProgram(cfg->saveImageFormat,
+                                                         &compressor,
+                                                         "save", false)) < 0)
+        goto cleanup;
+
     if (virDomainObjCheckActive(vm) < 0)
         goto cleanup;
 
@@ -2925,7 +2932,7 @@ qemuDomainManagedSave(virDomainPtr dom, unsigned int flags)
     if (virDomainManagedSaveEnsureACL(dom->conn, vm->def) < 0)
         goto cleanup;
 
-    ret = qemuDomainManagedSaveHelper(driver, vm, flags);
+    ret = qemuDomainManagedSaveHelper(driver, vm, NULL, flags);
 
  cleanup:
     virDomainObjEndAPI(&vm);
-- 
2.35.1