[libvirt RFCv8 10/27] qemu: saveimage: add virQEMUSaveFd APIs for multifd

[Claudio Fontana]

add APIs to Create, Close and Free MultiFD files to associate with
multifd channels.

Signed-off-by: Claudio Fontana <cfontana at suse.de>
---
 src/qemu/qemu_saveimage.c | 97 +++++++++++++++++++++++++++++++++++++++
 src/qemu/qemu_saveimage.h | 11 +++++
 2 files changed, 108 insertions(+)

diff --git a/src/qemu/qemu_saveimage.c b/src/qemu/qemu_saveimage.c
index 33807fe373..264868b5a4 100644
--- a/src/qemu/qemu_saveimage.c
+++ b/src/qemu/qemu_saveimage.c
@@ -365,6 +365,103 @@ int virQEMUSaveFdFini(virQEMUSaveFd *saveFd, virDomainObj *vm, int ret)
     return ret;
 }
 
+/*
+ * qemuSaveImageFreeMultiFd: free all multifd virQEMUSaveFds.
+ * @multiFd: the array of saveFds
+ * @vm:      the virDomainObj, to release lock
+ * @nconn:   number of multifd channels
+ * @ret:     the current operation result (< 0 is failure)
+ *
+ * If multiFd is NULL, the return value will be unchanged.
+ *
+ * Returns ret, or -1 if an error is detected.
+ */
+int qemuSaveImageFreeMultiFd(virQEMUSaveFd *multiFd, virDomainObj *vm, int nconn, int ret)
+{
+    int idx;
+
+    if (!multiFd)
+        return ret;
+
+    for (idx = 0; idx < nconn; idx++) {
+        ret = virQEMUSaveFdFini(&multiFd[idx], vm, ret);
+    }
+    /*
+     * do it again to unlink all in the error case,
+     * if error happened in the middle of previous loop.
+     */
+    for (idx = 0; idx < nconn; idx++) {
+        ret = virQEMUSaveFdFini(&multiFd[idx], vm, ret);
+    }
+    g_free(multiFd);
+    return ret;
+}
+
+/*
+ * qemuSaveImageCloseMultiFd: perform normal close on all multifd virQEMUSaveFds.
+ *
+ * @multiFd: the array of saveFds
+ * @nconn:   number of multifd channels
+ * @vm:      the virDomainObj, to release lock
+ *
+ * If multiFd is NULL, the function will return success.
+ * Returns -1 on error, 0 on success.
+ */
+int qemuSaveImageCloseMultiFd(virQEMUSaveFd *multiFd, int nconn, virDomainObj *vm)
+{
+    int idx;
+
+    if (!multiFd)
+        return 0;
+
+    for (idx = 0; idx < nconn; idx++) {
+        if (virQEMUSaveFdClose(&multiFd[idx], vm) < 0) {
+            return -1;
+        }
+    }
+    return 0;
+}
+
+/*
+ * qemuSaveImageCreateMultiFd: allocate and initialize all multifd virQEMUSaveFds.
+ *
+ * @driver:  qemu driver data
+ * @vm:      the virDomainObj
+ * @cmd:     the existing multifd helper command, to pass each fd as argument.
+ * @path:    pathname of the main file.
+ * @oflags:  the open flags desired, to be passed to virQEMUSaveFdInit.
+ * @cfg:     the driver config
+ * @nconn:   number of channel files to create or open, depending on oflags.
+ *
+ * Returns the new array of virQEMUSaveFds, or NULL on error.
+ */
+virQEMUSaveFd *
+qemuSaveImageCreateMultiFd(virQEMUDriver *driver, virDomainObj *vm,
+                           virCommand *cmd, const char *path,
+                           int oflags, virQEMUDriverConfig *cfg,
+                           int nconn)
+{
+    virQEMUSaveFd *multiFd = g_new0(virQEMUSaveFd, nconn);
+    int idx;
+
+    for (idx = 0; idx < nconn; idx++) {
+        virQEMUSaveFd *m = &multiFd[idx];
+        if (virQEMUSaveFdInit(m, path, idx + 1, oflags, cfg) < 0 ||
+            qemuSecuritySetImageFDLabel(driver->securityManager, vm->def, m->fd) < 0) {
+
+            virQEMUSaveFdFini(m, vm, -1);
+            goto error;
+        }
+        virCommandAddArgFormat(cmd, "%d", m->fd);
+        virCommandPassFD(cmd, m->fd, 0);
+    }
+    return multiFd;
+
+ error:
+    qemuSaveImageFreeMultiFd(multiFd, vm, nconn, -1);
+    return NULL;
+}
+
 
 /* Helper function to execute a migration to file with a correct save header
  * the caller needs to make sure that the processors are stopped and do all other
diff --git a/src/qemu/qemu_saveimage.h b/src/qemu/qemu_saveimage.h
index 5dc63f3661..b775c5eb08 100644
--- a/src/qemu/qemu_saveimage.h
+++ b/src/qemu/qemu_saveimage.h
@@ -72,6 +72,17 @@ int virQEMUSaveFdClose(virQEMUSaveFd *saveFd, virDomainObj *vm);
 
 int virQEMUSaveFdFini(virQEMUSaveFd *saveFd, virDomainObj *vm, int ret);
 
+virQEMUSaveFd *
+qemuSaveImageCreateMultiFd(virQEMUDriver *driver, virDomainObj *vm,
+                           virCommand *cmd, const char *path,
+                           int oflags, virQEMUDriverConfig *cfg,
+                           int nconn)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3) ATTRIBUTE_NONNULL(4) ATTRIBUTE_NONNULL(6);
+
+int qemuSaveImageCloseMultiFd(virQEMUSaveFd *multiFd, int nconn, virDomainObj *vm);
+
+int qemuSaveImageFreeMultiFd(virQEMUSaveFd *multiFd, virDomainObj *vm, int nconn, int ret);
+
 virDomainDef *
 qemuSaveImageUpdateDef(virQEMUDriver *driver,
                        virDomainDef *def,
-- 
2.35.3