qemu: Introduce virQEMUSaveData structure

The new structure encapsulates save image header and associated data
(domain XML).
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

src/qemu/qemu_driver.c

@@ -2811,6 +2811,14 @@ struct _virQEMUSaveHeader {
     uint32_t unused[15];
 };
 
+typedef struct _virQEMUSaveData virQEMUSaveData;
+typedef virQEMUSaveData *virQEMUSaveDataPtr;
+struct _virQEMUSaveData {
+    virQEMUSaveHeader header;
+    char *xml;
+};
+
+
 static inline void
 bswap_header(virQEMUSaveHeaderPtr hdr)
 {
@@ -2822,31 +2830,39 @@ bswap_header(virQEMUSaveHeaderPtr hdr)
 
 
 static void
-virQEMUSaveDataFree(virQEMUSaveHeaderPtr header)
+virQEMUSaveDataFree(virQEMUSaveDataPtr data)
 {
-    if (!header)
+    if (!data)
         return;
 
-    VIR_FREE(header);
+    VIR_FREE(data->xml);
+    VIR_FREE(data);
 }
 
 
-static virQEMUSaveHeaderPtr
-virQEMUSaveDataNew(char *domXML ATTRIBUTE_UNUSED,
+/**
+ * This function steals @domXML on success.
+ */
+static virQEMUSaveDataPtr
+virQEMUSaveDataNew(char *domXML,
                    bool running,
                    int compressed)
 {
-    virQEMUSaveHeaderPtr header = NULL;
+    virQEMUSaveDataPtr data = NULL;
+    virQEMUSaveHeaderPtr header;
 
-    if (VIR_ALLOC(header) < 0)
+    if (VIR_ALLOC(data) < 0)
         return NULL;
 
+    VIR_STEAL_PTR(data->xml, domXML);
+
+    header = &data->header;
     memcpy(header->magic, QEMU_SAVE_PARTIAL, sizeof(header->magic));
     header->version = QEMU_SAVE_VERSION;
     header->was_running = running ? 1 : 0;
     header->compressed = compressed;
 
-    return header;
+    return data;
 }
 
 
@@ -2860,17 +2876,17 @@ virQEMUSaveDataNew(char *domXML ATTRIBUTE_UNUSED,
  * Returns -1 on failure, or 0 on success.
  */
 static int
-virQEMUSaveDataWrite(virQEMUSaveHeaderPtr header,
-                     const char *xml,
+virQEMUSaveDataWrite(virQEMUSaveDataPtr data,
                      int fd,
                      const char *path)
 {
+    virQEMUSaveHeaderPtr header = &data->header;
     size_t len;
     int ret = -1;
     size_t zerosLen = 0;
     char *zeros = NULL;
 
-    len = strlen(xml) + 1;
+    len = strlen(data->xml) + 1;
 
     if (header->data_len > 0) {
         if (len > header->data_len) {
@@ -2893,7 +2909,7 @@ virQEMUSaveDataWrite(virQEMUSaveHeaderPtr header,
         goto cleanup;
     }
 
-    if (safewrite(fd, xml, header->data_len) != header->data_len ||
+    if (safewrite(fd, data->xml, header->data_len) != header->data_len ||
         safewrite(fd, zeros, zerosLen) != zerosLen) {
         virReportSystemError(errno,
                              _("failed to write domain xml to '%s'"),
@@ -2910,10 +2926,12 @@ virQEMUSaveDataWrite(virQEMUSaveHeaderPtr header,
 
 
 static int
-virQEMUSaveDataFinish(virQEMUSaveHeaderPtr header,
+virQEMUSaveDataFinish(virQEMUSaveDataPtr data,
                       int *fd,
                       const char *path)
 {
+    virQEMUSaveHeaderPtr header = &data->header;
+
     memcpy(header->magic, QEMU_SAVE_MAGIC, sizeof(header->magic));
 
     if (safewrite(*fd, header, sizeof(*header)) != sizeof(*header) ||
@@ -3142,8 +3160,7 @@ static int
 qemuDomainSaveMemory(virQEMUDriverPtr driver,
                      virDomainObjPtr vm,
                      const char *path,
-                     const char *domXML,
-                     virQEMUSaveHeaderPtr header,
+                     virQEMUSaveDataPtr data,
                      const char *compressedpath,
                      unsigned int flags,
                      qemuDomainAsyncJob asyncJob)
@@ -3178,7 +3195,7 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver,
     if (!(wrapperFd = virFileWrapperFdNew(&fd, path, wrapperFlags)))
         goto cleanup;
 
-    if (virQEMUSaveDataWrite(header, domXML, fd, path) < 0)
+    if (virQEMUSaveDataWrite(data, fd, path) < 0)
         goto cleanup;
 
     /* Perform the migration */
@@ -3200,7 +3217,7 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver,
         goto cleanup;
 
     if ((fd = qemuOpenFile(driver, vm, path, O_WRONLY, NULL, NULL)) < 0 ||
-        virQEMUSaveDataFinish(header, &fd, path) < 0)
+        virQEMUSaveDataFinish(data, &fd, path) < 0)
         goto cleanup;
 
     ret = 0;
@@ -3232,7 +3249,7 @@ qemuDomainSaveInternal(virQEMUDriverPtr driver, virDomainPtr dom,
     virObjectEventPtr event = NULL;
     qemuDomainObjPrivatePtr priv = vm->privateData;
     virCapsPtr caps;
-    virQEMUSaveHeaderPtr header = NULL;
+    virQEMUSaveDataPtr data = NULL;
 
     if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
         goto cleanup;
@@ -3298,10 +3315,11 @@ qemuDomainSaveInternal(virQEMUDriverPtr driver, virDomainPtr dom,
         goto endjob;
     }
 
-    if (!(header = virQEMUSaveDataNew(xml, was_running, compressed)))
+    if (!(data = virQEMUSaveDataNew(xml, was_running, compressed)))
         goto endjob;
+    xml = NULL;
 
-    ret = qemuDomainSaveMemory(driver, vm, path, xml, header, compressedpath,
+    ret = qemuDomainSaveMemory(driver, vm, path, data, compressedpath,
                                flags, QEMU_ASYNC_JOB_SAVE);
     if (ret < 0)
         goto endjob;
@@ -3335,7 +3353,7 @@ qemuDomainSaveInternal(virQEMUDriverPtr driver, virDomainPtr dom,
 
  cleanup:
     VIR_FREE(xml);
-    virQEMUSaveDataFree(header);
+    virQEMUSaveDataFree(data);
     qemuDomainEventQueue(driver, event);
     virObjectUnref(caps);
     return ret;
@@ -6244,8 +6262,7 @@ qemuDomainSaveImageUpdateDef(virQEMUDriverPtr driver,
  * @driver: qemu driver data
  * @path: path of the save image
  * @ret_def: returns domain definition created from the XML stored in the image
- * @ret_header: returns structure filled with data from the image header
- * @xmlout: returns the XML from the image file (may be NULL)
+ * @ret_data: returns structure filled with data from the image header
  * @bypass_cache: bypass cache when opening the file
  * @wrapperFd: returns the file wrapper structure
  * @open_write: open the file for writing (for updates)
@@ -6259,16 +6276,15 @@ static int ATTRIBUTE_NONNULL(3) ATTRIBUTE_NONNULL(4)
 qemuDomainSaveImageOpen(virQEMUDriverPtr driver,
                         const char *path,
                         virDomainDefPtr *ret_def,
-                        virQEMUSaveHeaderPtr *ret_header,
-                        char **xmlout,
+                        virQEMUSaveDataPtr *ret_data,
                         bool bypass_cache,
                         virFileWrapperFdPtr *wrapperFd,
                         bool open_write,
                         bool unlink_corrupt)
 {
     int fd = -1;
-    char *xml = NULL;
-    virQEMUSaveHeaderPtr header = NULL;
+    virQEMUSaveDataPtr data = NULL;
+    virQEMUSaveHeaderPtr header;
     virDomainDefPtr def = NULL;
     int oflags = open_write ? O_RDWR : O_RDONLY;
     virCapsPtr caps = NULL;
@@ -6293,9 +6309,10 @@ qemuDomainSaveImageOpen(virQEMUDriverPtr driver,
                                            VIR_FILE_WRAPPER_BYPASS_CACHE)))
         goto error;
 
-    if (VIR_ALLOC(header) < 0)
+    if (VIR_ALLOC(data) < 0)
         goto error;
 
+    header = &data->header;
     if (saferead(fd, header, sizeof(*header)) != sizeof(*header)) {
         if (unlink_corrupt) {
             if (VIR_CLOSE(fd) < 0 || unlink(path) < 0) {
@@ -6347,32 +6364,27 @@ qemuDomainSaveImageOpen(virQEMUDriverPtr driver,
 
     if (header->data_len <= 0) {
         virReportError(VIR_ERR_OPERATION_FAILED,
-                       _("invalid XML length: %d"), header->data_len);
+                       _("invalid header data length: %d"), header->data_len);
         goto error;
     }
 
-    if (VIR_ALLOC_N(xml, header->data_len) < 0)
+    if (VIR_ALLOC_N(data->xml, header->data_len) < 0)
         goto error;
 
-    if (saferead(fd, xml, header->data_len) != header->data_len) {
+    if (saferead(fd, data->xml, header->data_len) != header->data_len) {
         virReportError(VIR_ERR_OPERATION_FAILED,
-                       "%s", _("failed to read XML"));
+                       "%s", _("failed to read domain XML"));
         goto error;
     }
 
     /* Create a domain from this XML */
-    if (!(def = virDomainDefParseString(xml, caps, driver->xmlopt, NULL,
+    if (!(def = virDomainDefParseString(data->xml, caps, driver->xmlopt, NULL,
                                         VIR_DOMAIN_DEF_PARSE_INACTIVE |
                                         VIR_DOMAIN_DEF_PARSE_SKIP_VALIDATE)))
         goto error;
 
-    if (xmlout)
-        *xmlout = xml;
-    else
-        VIR_FREE(xml);
-
     *ret_def = def;
-    *ret_header = header;
+    *ret_data = data;
 
     virObjectUnref(caps);
 
@@ -6380,8 +6392,7 @@ qemuDomainSaveImageOpen(virQEMUDriverPtr driver,
 
  error:
     virDomainDefFree(def);
-    VIR_FREE(xml);
-    virQEMUSaveDataFree(header);
+    virQEMUSaveDataFree(data);
     VIR_FORCE_CLOSE(fd);
     virObjectUnref(caps);
 
@@ -6393,7 +6404,7 @@ qemuDomainSaveImageStartVM(virConnectPtr conn,
                            virQEMUDriverPtr driver,
                            virDomainObjPtr vm,
                            int *fd,
-                           virQEMUSaveHeaderPtr header,
+                           virQEMUSaveDataPtr data,
                            const char *path,
                            bool start_paused,
                            qemuDomainAsyncJob asyncJob)
@@ -6405,6 +6416,7 @@ qemuDomainSaveImageStartVM(virConnectPtr conn,
     virCommandPtr cmd = NULL;
     char *errbuf = NULL;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    virQEMUSaveHeaderPtr header = &data->header;
 
     if ((header->version == 2) &&
         (header->compressed != QEMU_SAVE_FORMAT_RAW)) {
@@ -6514,12 +6526,11 @@ qemuDomainRestoreFlags(virConnectPtr conn,
     qemuDomainObjPrivatePtr priv = NULL;
     virDomainDefPtr def = NULL;
     virDomainObjPtr vm = NULL;
-    char *xml = NULL;
     char *xmlout = NULL;
     const char *newxml = dxml;
     int fd = -1;
     int ret = -1;
-    virQEMUSaveHeaderPtr header = NULL;
+    virQEMUSaveDataPtr data = NULL;
     virFileWrapperFdPtr wrapperFd = NULL;
     bool hook_taint = false;
 
@@ -6530,7 +6541,7 @@ qemuDomainRestoreFlags(virConnectPtr conn,
 
     virNWFilterReadLockFilterUpdates();
 
-    fd = qemuDomainSaveImageOpen(driver, path, &def, &header, &xml,
+    fd = qemuDomainSaveImageOpen(driver, path, &def, &data,
                                  (flags & VIR_DOMAIN_SAVE_BYPASS_CACHE) != 0,
                                  &wrapperFd, false, false);
     if (fd < 0)
@@ -6546,7 +6557,7 @@ qemuDomainRestoreFlags(virConnectPtr conn,
                                    VIR_HOOK_QEMU_OP_RESTORE,
                                    VIR_HOOK_SUBOP_BEGIN,
                                    NULL,
-                                   dxml ? dxml : xml,
+                                   dxml ? dxml : data->xml,
                                    &xmlout)) < 0)
             goto cleanup;
 
@@ -6576,9 +6587,9 @@ qemuDomainRestoreFlags(virConnectPtr conn,
     def = NULL;
 
     if (flags & VIR_DOMAIN_SAVE_RUNNING)
-        header->was_running = 1;
+        data->header.was_running = 1;
     else if (flags & VIR_DOMAIN_SAVE_PAUSED)
-        header->was_running = 0;
+        data->header.was_running = 0;
 
     if (hook_taint) {
         priv = vm->privateData;
@@ -6588,7 +6599,7 @@ qemuDomainRestoreFlags(virConnectPtr conn,
     if (qemuProcessBeginJob(driver, vm, VIR_DOMAIN_JOB_OPERATION_RESTORE) < 0)
         goto cleanup;
 
-    ret = qemuDomainSaveImageStartVM(conn, driver, vm, &fd, header, path,
+    ret = qemuDomainSaveImageStartVM(conn, driver, vm, &fd, data, path,
                                      false, QEMU_ASYNC_JOB_START);
     if (virFileWrapperFdClose(wrapperFd) < 0)
         VIR_WARN("Failed to close %s", path);
@@ -6598,8 +6609,7 @@ qemuDomainRestoreFlags(virConnectPtr conn,
  cleanup:
     virDomainDefFree(def);
     VIR_FORCE_CLOSE(fd);
-    VIR_FREE(xml);
-    virQEMUSaveDataFree(header);
+    virQEMUSaveDataFree(data);
     VIR_FREE(xmlout);
     virFileWrapperFdFree(wrapperFd);
     if (vm && ret < 0)
@@ -6624,12 +6634,12 @@ qemuDomainSaveImageGetXMLDesc(virConnectPtr conn, const char *path,
     char *ret = NULL;
     virDomainDefPtr def = NULL;
     int fd = -1;
-    virQEMUSaveHeaderPtr header = NULL;
+    virQEMUSaveDataPtr data = NULL;
 
     /* We only take subset of virDomainDefFormat flags.  */
     virCheckFlags(VIR_DOMAIN_XML_SECURE, NULL);
 
-    fd = qemuDomainSaveImageOpen(driver, path, &def, &header, NULL,
+    fd = qemuDomainSaveImageOpen(driver, path, &def, &data,
                                  false, NULL, false, false);
 
     if (fd < 0)
@@ -6641,7 +6651,7 @@ qemuDomainSaveImageGetXMLDesc(virConnectPtr conn, const char *path,
     ret = qemuDomainDefFormatXML(driver, def, flags);
 
  cleanup:
-    virQEMUSaveDataFree(header);
+    virQEMUSaveDataFree(data);
     virDomainDefFree(def);
     VIR_FORCE_CLOSE(fd);
     return ret;
@@ -6656,8 +6666,7 @@ qemuDomainSaveImageDefineXML(virConnectPtr conn, const char *path,
     virDomainDefPtr def = NULL;
     virDomainDefPtr newdef = NULL;
     int fd = -1;
-    char *xml = NULL;
-    virQEMUSaveHeaderPtr header = NULL;
+    virQEMUSaveDataPtr data = NULL;
     int state = -1;
 
     virCheckFlags(VIR_DOMAIN_SAVE_RUNNING |
@@ -6668,7 +6677,7 @@ qemuDomainSaveImageDefineXML(virConnectPtr conn, const char *path,
     else if (flags & VIR_DOMAIN_SAVE_PAUSED)
         state = 0;
 
-    fd = qemuDomainSaveImageOpen(driver, path, &def, &header, &xml,
+    fd = qemuDomainSaveImageOpen(driver, path, &def, &data,
                                  false, NULL, true, false);
 
     if (fd < 0)
@@ -6677,25 +6686,25 @@ qemuDomainSaveImageDefineXML(virConnectPtr conn, const char *path,
     if (virDomainSaveImageDefineXMLEnsureACL(conn, def) < 0)
         goto cleanup;
 
-    if (STREQ(xml, dxml) &&
-        (state < 0 || state == header->was_running)) {
+    if (STREQ(data->xml, dxml) &&
+        (state < 0 || state == data->header.was_running)) {
         /* no change to the XML */
         ret = 0;
         goto cleanup;
     }
 
     if (state >= 0)
-        header->was_running = state;
+        data->header.was_running = state;
 
     if (!(newdef = qemuDomainSaveImageUpdateDef(driver, def, dxml)))
         goto cleanup;
 
-    VIR_FREE(xml);
+    VIR_FREE(data->xml);
 
-    if (!(xml = qemuDomainDefFormatXML(driver, newdef,
-                                       VIR_DOMAIN_XML_INACTIVE |
-                                       VIR_DOMAIN_XML_SECURE |
-                                       VIR_DOMAIN_XML_MIGRATABLE)))
+    if (!(data->xml = qemuDomainDefFormatXML(driver, newdef,
+                                             VIR_DOMAIN_XML_INACTIVE |
+                                             VIR_DOMAIN_XML_SECURE |
+                                             VIR_DOMAIN_XML_MIGRATABLE)))
         goto cleanup;
 
     if (lseek(fd, 0, SEEK_SET) != 0) {
@@ -6703,7 +6712,7 @@ qemuDomainSaveImageDefineXML(virConnectPtr conn, const char *path,
         goto cleanup;
     }
 
-    if (virQEMUSaveDataWrite(header, xml, fd, path) < 0)
+    if (virQEMUSaveDataWrite(data, fd, path) < 0)
         goto cleanup;
 
     if (VIR_CLOSE(fd) < 0) {
@@ -6717,8 +6726,7 @@ qemuDomainSaveImageDefineXML(virConnectPtr conn, const char *path,
     virDomainDefFree(def);
     virDomainDefFree(newdef);
     VIR_FORCE_CLOSE(fd);
-    VIR_FREE(xml);
-    virQEMUSaveDataFree(header);
+    virQEMUSaveDataFree(data);
     return ret;
 }
 
@@ -6737,12 +6745,11 @@ qemuDomainObjRestore(virConnectPtr conn,
     qemuDomainObjPrivatePtr priv = vm->privateData;
     int fd = -1;
     int ret = -1;
-    char *xml = NULL;
     char *xmlout = NULL;
-    virQEMUSaveHeaderPtr header = NULL;
+    virQEMUSaveDataPtr data = NULL;
     virFileWrapperFdPtr wrapperFd = NULL;
 
-    fd = qemuDomainSaveImageOpen(driver, path, &def, &header, &xml,
+    fd = qemuDomainSaveImageOpen(driver, path, &def, &data,
                                  bypass_cache, &wrapperFd, false, true);
     if (fd < 0) {
         if (fd == -3)
@@ -6756,7 +6763,7 @@ qemuDomainObjRestore(virConnectPtr conn,
         if ((hookret = virHookCall(VIR_HOOK_DRIVER_QEMU, def->name,
                                    VIR_HOOK_QEMU_OP_RESTORE,
                                    VIR_HOOK_SUBOP_BEGIN,
-                                   NULL, xml, &xmlout)) < 0)
+                                   NULL, data->xml, &xmlout)) < 0)
             goto cleanup;
 
         if (hookret == 0 && !virStringIsEmpty(xmlout)) {
@@ -6790,14 +6797,13 @@ qemuDomainObjRestore(virConnectPtr conn,
     virDomainObjAssignDef(vm, def, true, NULL);
     def = NULL;
 
-    ret = qemuDomainSaveImageStartVM(conn, driver, vm, &fd, header, path,
+    ret = qemuDomainSaveImageStartVM(conn, driver, vm, &fd, data, path,
                                      start_paused, asyncJob);
     if (virFileWrapperFdClose(wrapperFd) < 0)
         VIR_WARN("Failed to close %s", path);
 
  cleanup:
-    VIR_FREE(xml);
-    virQEMUSaveDataFree(header);
+    virQEMUSaveDataFree(data);
     VIR_FREE(xmlout);
     virDomainDefFree(def);
     VIR_FORCE_CLOSE(fd);
@@ -14363,7 +14369,7 @@ qemuDomainSnapshotCreateActiveExternal(virConnectPtr conn,
     virQEMUDriverConfigPtr cfg = NULL;
     int compressed;
     char *compressedpath = NULL;
-    virQEMUSaveHeaderPtr header = NULL;
+    virQEMUSaveDataPtr data = NULL;
 
     /* If quiesce was requested, then issue a freeze command, and a
      * counterpart thaw command when it is actually sent to agent.
@@ -14435,10 +14441,11 @@ qemuDomainSnapshotCreateActiveExternal(virConnectPtr conn,
         if (!(xml = qemuDomainDefFormatLive(driver, vm->def, true, true)))
             goto cleanup;
 
-        if (!(header = virQEMUSaveDataNew(xml, resume, compressed)))
+        if (!(data = virQEMUSaveDataNew(xml, resume, compressed)))
             goto cleanup;
+        xml = NULL;
 
-        if ((ret = qemuDomainSaveMemory(driver, vm, snap->def->file, xml, header,
+        if ((ret = qemuDomainSaveMemory(driver, vm, snap->def->file, data,
                                         compressedpath, 0,
                                         QEMU_ASYNC_JOB_SNAPSHOT)) < 0)
             goto cleanup;
@@ -14508,7 +14515,7 @@ qemuDomainSnapshotCreateActiveExternal(virConnectPtr conn,
             ret = -1;
     }
 
-    virQEMUSaveDataFree(header);
+    virQEMUSaveDataFree(data);
     VIR_FREE(xml);
     VIR_FREE(compressedpath);
     virObjectUnref(cfg);