From 4a304d9114e1b2e2f69fdb0857501ad8db03d17b Mon Sep 17 00:00:00 2001

Message-Id: <4a304d9114e1b2e2f69fdb0857501ad8db03d17b@dist-git>

From: Jiri Denemark <jdenemar@redhat.com>

Date: Tue, 6 Jun 2017 23:41:57 +0200

Subject: [PATCH] qemu: Refactor qemuDomainSaveHeader

The function is now called virQEMUSaveDataWrite and it is now doing

everything it needs to save both the save image header and domain XML to

a file. Be it a new file or an existing file in which a user wants to

change the domain XML.

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

Reviewed-by: Pavel Hrdina <phrdina@redhat.com>

(cherry picked from commit 33ae270bee012fc89d7b8bb23986ce837ee21b0e)

https://bugzilla.redhat.com/show_bug.cgi?id=1441662

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

---

 src/qemu/qemu_driver.c | 98 ++++++++++++++++++++++++++++++--------------------

 1 file changed, 60 insertions(+), 38 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c

index a0b607b419..1629f27470 100644

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

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

@@ -2837,7 +2837,7 @@ virQEMUSaveDataFree(virQEMUSaveHeaderPtr header)

 static virQEMUSaveHeaderPtr

-virQEMUSaveDataNew(char *domXML,

+virQEMUSaveDataNew(char *domXML ATTRIBUTE_UNUSED,

                    bool running,

                    int compressed)

 {

@@ -2850,34 +2850,66 @@ virQEMUSaveDataNew(char *domXML,

     header->version = QEMU_SAVE_VERSION;

     header->was_running = running ? 1 : 0;

     header->compressed = compressed;

-    header->data_len = strlen(domXML) + 1;

     return header;

 }

-/* return -errno on failure, or 0 on success */

+/* virQEMUSaveDataWrite:

+ *

+ * Writes libvirt's header (including domain XML) into a saved image of a

+ * running domain. If @header has data_len filled in (because it was previously

+ * read from the file), the function will make sure the new data will fit

+ * within data_len.

+ *

+ * Returns -1 on failure, or 0 on success.

+ */

 static int

-qemuDomainSaveHeader(int fd, const char *path, const char *xml,

-                     virQEMUSaveHeaderPtr header)

+virQEMUSaveDataWrite(virQEMUSaveHeaderPtr header,

+                     const char *xml,

+                     int fd,

+                     const char *path)

 {

-    int ret = 0;

+    size_t len;

+    int ret = -1;

+    size_t zerosLen = 0;

+    char *zeros = NULL;

+

+    len = strlen(xml) + 1;

+

+    if (header->data_len > 0) {

+        if (len > header->data_len) {

+            virReportError(VIR_ERR_OPERATION_FAILED, "%s",

+                           _("new xml too large to fit in file"));

+            goto cleanup;

+        }

+

+        zerosLen = header->data_len - len;

+        if (VIR_ALLOC_N(zeros, zerosLen) < 0)

+            goto cleanup;

+    } else {

+        header->data_len = len;

+    }

     if (safewrite(fd, header, sizeof(*header)) != sizeof(*header)) {

-        ret = -errno;

-        virReportError(VIR_ERR_OPERATION_FAILED,

-                       _("failed to write header to domain save file '%s'"),

-                       path);

-        goto endjob;

+        virReportSystemError(errno,

+                             _("failed to write header to domain save file '%s'"),

+                             path);

+        goto cleanup;

     }

-    if (safewrite(fd, xml, header->data_len) != header->data_len) {

-        ret = -errno;

-        virReportError(VIR_ERR_OPERATION_FAILED,

-                       _("failed to write xml to '%s'"), path);

-        goto endjob;

+    if (safewrite(fd, xml, header->data_len) != header->data_len ||

+        safewrite(fd, zeros, zerosLen) != zerosLen) {

+        virReportSystemError(errno,

+                             _("failed to write domain xml to '%s'"),

+                             path);

+        goto cleanup;

     }

- endjob:

+

+    ret = 0;

+

+ cleanup:

+    VIR_FREE(zeros);

     return ret;

 }

@@ -3132,8 +3164,7 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver,

     if (!(wrapperFd = virFileWrapperFdNew(&fd, path, wrapperFlags)))

         goto cleanup;

-    /* Write header to file, followed by XML */

-    if (qemuDomainSaveHeader(fd, path, domXML, header) < 0)

+    if (virQEMUSaveDataWrite(header, domXML, fd, path) < 0)

         goto cleanup;

     /* Perform the migration */

@@ -6620,7 +6651,6 @@ qemuDomainSaveImageDefineXML(virConnectPtr conn, const char *path,

     virDomainDefPtr newdef = NULL;

     int fd = -1;

     char *xml = NULL;

-    size_t len;

     virQEMUSaveHeaderPtr header = NULL;

     int state = -1;

@@ -6656,30 +6686,22 @@ qemuDomainSaveImageDefineXML(virConnectPtr conn, const char *path,

     VIR_FREE(xml);

-    xml = qemuDomainDefFormatXML(driver, newdef,

-                                 VIR_DOMAIN_XML_INACTIVE |

-                                 VIR_DOMAIN_XML_SECURE |

-                                 VIR_DOMAIN_XML_MIGRATABLE);

-    if (!xml)

-        goto cleanup;

-    len = strlen(xml) + 1;

-

-    if (len > header->data_len) {

-        virReportError(VIR_ERR_OPERATION_FAILED, "%s",

-                       _("new xml too large to fit in file"));

-        goto cleanup;

-    }

-    if (VIR_EXPAND_N(xml, len, header->data_len - len) < 0)

+    if (!(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) {

         virReportSystemError(errno, _("cannot seek in '%s'"), path);

         goto cleanup;

     }

-    if (safewrite(fd, &header, sizeof(header)) != sizeof(header) ||

-        safewrite(fd, xml, len) != len ||

-        VIR_CLOSE(fd) < 0) {

-        virReportSystemError(errno, _("failed to write xml to '%s'"), path);

+

+    if (virQEMUSaveDataWrite(header, xml, fd, path) < 0)

+        goto cleanup;

+

+    if (VIR_CLOSE(fd) < 0) {

+        virReportSystemError(errno, _("failed to write header data to '%s'"), path);

         goto cleanup;

     }

-- 

2.13.1