ch_driver: Add domainSave, domainSaveFlags callbacks

Implemented save callbacks. CH's vmm.snapshot API is called to save the
domain state. The path passed to these callbacks has to be of directory
as CH takes dir as input to snapshot and saves multiple files under it.

Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi@linux.microsoft.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

src/ch/ch_conf.h

@@ -81,6 +81,17 @@ struct _virCHDriver
     ebtablesContext *ebtables;
 };
 
+#define CH_SAVE_MAGIC "libvirt-xml\n \0 \r"
+#define CH_SAVE_XML "libvirt-save.xml"
+
+typedef struct _CHSaveXMLHeader CHSaveXMLHeader;
+struct _CHSaveXMLHeader {
+    char magic[sizeof(CH_SAVE_MAGIC)-1];
+    uint32_t xmlLen;
+    /* 20 bytes used, pad up to 64 bytes */
+    uint32_t unused[11];
+};
+
 virCaps *virCHDriverCapsInit(void);
 virCaps *virCHDriverGetCapabilities(virCHDriver *driver,
                                       bool refresh);

src/ch/ch_driver.c

@@ -19,6 +19,7 @@
  */
 
 #include <config.h>
+#include <fcntl.h>
 
 #include "ch_capabilities.h"
 #include "ch_conf.h"
@@ -34,6 +35,7 @@
 #include "virerror.h"
 #include "virlog.h"
 #include "virobject.h"
+#include "virfile.h"
 #include "virtypedparam.h"
 #include "virutil.h"
 #include "viruuid.h"
@@ -621,6 +623,146 @@ chDomainDestroy(virDomainPtr dom)
     return chDomainDestroyFlags(dom, 0);
 }
 
+/**
+ * chDoDomainSave:
+ * @driver: pointer to driver structure
+ * @vm: pointer to virtual machine structure. Must be locked before invocation.
+ * @to_dir: directory path (CH needs directory input) to save the domain
+ * @managed: whether the VM is managed or not
+ *
+ * Checks if the domain is running or paused, then suspends it and saves it
+ * using CH's vmm.snapshot API. CH creates multiple files for config, memory,
+ * device state into @to_dir.
+ *
+ * Returns 0 on success or -1 in case of error
+ */
+static int
+chDoDomainSave(virCHDriver *driver,
+               virDomainObj *vm,
+               const char *to_dir,
+               bool managed)
+{
+    g_autoptr(virCHDriverConfig) cfg = virCHDriverGetConfig(driver);
+    virCHDomainObjPrivate *priv = vm->privateData;
+    CHSaveXMLHeader hdr;
+    g_autofree char *to = NULL;
+    g_autofree char *xml = NULL;
+    uint32_t xml_len;
+    VIR_AUTOCLOSE fd = -1;
+    int ret = -1;
+
+    virDomainState domainState = virDomainObjGetState(vm, NULL);
+    if (domainState == VIR_DOMAIN_RUNNING) {
+        if (virCHMonitorSuspendVM(priv->monitor) < 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("failed to suspend domain before saving"));
+            goto end;
+        }
+        virDomainObjSetState(vm, VIR_DOMAIN_PAUSED, VIR_DOMAIN_PAUSED_SAVE);
+    } else if (domainState != VIR_DOMAIN_PAUSED) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("only can save running/paused domain"));
+        goto end;
+    }
+
+    if (virDirCreate(to_dir, 0770, cfg->user, cfg->group,
+                     VIR_DIR_CREATE_ALLOW_EXIST) < 0) {
+        virReportSystemError(errno, _("Failed to create SAVE dir %1$s"), to_dir);
+        goto end;
+    }
+
+    to = g_strdup_printf("%s/%s", to_dir, CH_SAVE_XML);
+    if ((fd = virFileOpenAs(to, O_CREAT|O_TRUNC|O_WRONLY, S_IRUSR|S_IWUSR,
+                            cfg->user, cfg->group, 0)) < 0) {
+        virReportSystemError(-fd,
+                             _("Failed to create/open domain save xml file '%1$s'"),
+                             to);
+        goto end;
+    }
+
+    if ((xml = virDomainDefFormat(vm->def, driver->xmlopt, 0)) == NULL)
+        goto end;
+    xml_len = strlen(xml) + 1;
+
+    memset(&hdr, 0, sizeof(hdr));
+    memcpy(hdr.magic, CH_SAVE_MAGIC, sizeof(hdr.magic));
+    hdr.xmlLen = xml_len;
+
+    if (safewrite(fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
+        virReportSystemError(errno, "%s", _("Failed to write file header"));
+        goto end;
+    }
+
+    if (safewrite(fd, xml, xml_len) != xml_len) {
+        virReportSystemError(errno, "%s", _("Failed to write xml definition"));
+        goto end;
+    }
+
+    if (virCHMonitorSaveVM(priv->monitor, to_dir) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("Failed to save domain"));
+        goto end;
+    }
+
+    if (virCHProcessStop(driver, vm, VIR_DOMAIN_SHUTOFF_SAVED) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Failed to shutoff after domain save"));
+        goto end;
+    }
+
+    vm->hasManagedSave = managed;
+    ret = 0;
+
+ end:
+    return ret;
+}
+
+static int
+chDomainSaveFlags(virDomainPtr dom, const char *to, const char *dxml, unsigned int flags)
+{
+    virCHDriver *driver = dom->conn->privateData;
+    virDomainObj *vm = NULL;
+    int ret = -1;
+
+    virCheckFlags(0, -1);
+    if (dxml) {
+        virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
+                       _("xml modification unsupported"));
+        return -1;
+    }
+
+    if (!(vm = virCHDomainObjFromDomain(dom)))
+        goto cleanup;
+
+    if (virDomainSaveFlagsEnsureACL(dom->conn, vm->def) < 0)
+        goto cleanup;
+
+    if (virDomainObjBeginJob(vm, VIR_JOB_MODIFY) < 0)
+        goto cleanup;
+
+    if (virDomainObjCheckActive(vm) < 0)
+        goto endjob;
+
+    if (chDoDomainSave(driver, vm, to, false) < 0)
+        goto endjob;
+
+    /* Remove if VM is not persistent */
+    virCHDomainRemoveInactive(driver, vm);
+    ret = 0;
+
+ endjob:
+    virDomainObjEndJob(vm);
+
+ cleanup:
+    virDomainObjEndAPI(&vm);
+    return ret;
+}
+
+static int
+chDomainSave(virDomainPtr dom, const char *to)
+{
+    return chDomainSaveFlags(dom, to, NULL, 0);
+}
+
 static virDomainPtr chDomainLookupByID(virConnectPtr conn,
                                        int id)
 {
@@ -1742,6 +1884,8 @@ static virHypervisorDriver chHypervisorDriver = {
     .nodeGetCPUMap = chNodeGetCPUMap,                       /* 8.0.0 */
     .domainSetNumaParameters = chDomainSetNumaParameters,   /* 8.1.0 */
     .domainGetNumaParameters = chDomainGetNumaParameters,   /* 8.1.0 */
+    .domainSave = chDomainSave,                             /* 10.2.0 */
+    .domainSaveFlags = chDomainSaveFlags,                   /* 10.2.0 */
 };
 
 static virConnectDriver chConnectDriver = {