vz: don't pass empty and unused fields in migration cookie

The first version of migration cookie was rather dumb resulting
in passing empty or unused fields here and there. Add flags to
specify what to bake to and eat from cookie so we deal only
with meaningful data. However for backwards compatibility
we still need to pass at least some faked fields sometimes.

Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>

diff --git a/src/vz/vz_driver.c b/src/vz/vz_driver.c
index b17cea7d8d1a5f6778c87ebfb420931cae93120c..d5c0cad841748dc5eee23fd02667795ca2126df1 100644 (file)
--- a/src/vz/vz_driver.c
+++ b/src/vz/vz_driver.c
@@ -2138,11 +2138,17 @@ vzDomainRevertToSnapshot(virDomainSnapshotPtr snapshot, unsigned int flags)
     return ret;
 }
 
+enum vzMigrationCookieFeatures {
+    VZ_MIGRATION_COOKIE_SESSION_UUID  = (1 << 0),
+    VZ_MIGRATION_COOKIE_DOMAIN_UUID = (1 << 1),
+    VZ_MIGRATION_COOKIE_DOMAIN_NAME = (1 << 1),
+};
+
 typedef struct _vzMigrationCookie vzMigrationCookie;
 typedef vzMigrationCookie *vzMigrationCookiePtr;
 struct _vzMigrationCookie {
-    unsigned char session_uuid[VIR_UUID_BUFLEN];
-    unsigned char uuid[VIR_UUID_BUFLEN];
+    unsigned char *session_uuid;
+    unsigned char *uuid;
     char *name;
 };
 
@@ -2151,12 +2157,18 @@ vzMigrationCookieFree(vzMigrationCookiePtr mig)
 {
     if (!mig)
         return;
+
+    VIR_FREE(mig->session_uuid);
+    VIR_FREE(mig->uuid);
     VIR_FREE(mig->name);
     VIR_FREE(mig);
 }
 
 static int
-vzBakeCookie(vzMigrationCookiePtr mig, char **cookieout, int *cookieoutlen)
+vzBakeCookie(vzDriverPtr driver,
+             virDomainObjPtr dom,
+             char **cookieout, int *cookieoutlen,
+             unsigned int flags)
 {
     char uuidstr[VIR_UUID_STRING_BUFLEN];
     virBuffer buf = VIR_BUFFER_INITIALIZER;
@@ -2172,11 +2184,28 @@ vzBakeCookie(vzMigrationCookiePtr mig, char **cookieout, int *cookieoutlen)
 
     virBufferAddLit(&buf, "<vz-migration>\n");
     virBufferAdjustIndent(&buf, 2);
-    virUUIDFormat(mig->session_uuid, uuidstr);
-    virBufferAsprintf(&buf, "<session-uuid>%s</session-uuid>\n", uuidstr);
-    virUUIDFormat(mig->uuid, uuidstr);
-    virBufferAsprintf(&buf, "<uuid>%s</uuid>\n", uuidstr);
-    virBufferAsprintf(&buf, "<name>%s</name>\n", mig->name);
+
+    if (flags & VZ_MIGRATION_COOKIE_SESSION_UUID) {
+        virUUIDFormat(driver->session_uuid, uuidstr);
+        virBufferAsprintf(&buf, "<session-uuid>%s</session-uuid>\n", uuidstr);
+    }
+
+    if (flags & VZ_MIGRATION_COOKIE_DOMAIN_UUID) {
+        unsigned char fakeuuid[VIR_UUID_BUFLEN] = { 0 };
+
+        /* if dom is NULL just pass some parsable uuid for backward compat.
+         * It is not used by peer */
+        virUUIDFormat(dom ? dom->def->uuid : fakeuuid, uuidstr);
+        virBufferAsprintf(&buf, "<uuid>%s</uuid>\n", uuidstr);
+    }
+
+    if (flags & VZ_MIGRATION_COOKIE_DOMAIN_NAME) {
+        /* if dom is NULL just pass some name for backward compat.
+         * It is not used by peer */
+        virBufferAsprintf(&buf, "<name>%s</name>\n", dom ? dom->def->name :
+                                                           "__fakename__");
+    }
+
     virBufferAdjustIndent(&buf, -2);
     virBufferAddLit(&buf, "</vz-migration>\n");
 
@@ -2190,11 +2219,11 @@ vzBakeCookie(vzMigrationCookiePtr mig, char **cookieout, int *cookieoutlen)
 }
 
 static vzMigrationCookiePtr
-vzEatCookie(const char *cookiein, int cookieinlen)
+vzEatCookie(const char *cookiein, int cookieinlen, unsigned int flags)
 {
     xmlDocPtr doc = NULL;
     xmlXPathContextPtr ctx = NULL;
-    char *tmp;
+    char *tmp = NULL;
     vzMigrationCookiePtr mig = NULL;
 
     if (VIR_ALLOC(mig) < 0)
@@ -2210,33 +2239,31 @@ vzEatCookie(const char *cookiein, int cookieinlen)
                                       _("(_migration_cookie)"), &ctx)))
         goto error;
 
-    if (!(tmp = virXPathString("string(./session-uuid[1])", ctx))) {
-        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                       _("missing session-uuid element in migration data"));
-        goto error;
-    }
-    if (virUUIDParse(tmp, mig->session_uuid) < 0) {
+    if ((flags & VZ_MIGRATION_COOKIE_SESSION_UUID)
+        && (!(tmp = virXPathString("string(./session-uuid[1])", ctx))
+            || (VIR_ALLOC_N(mig->session_uuid, VIR_UUID_BUFLEN) < 0)
+            || (virUUIDParse(tmp, mig->session_uuid) < 0))) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                       _("malformed session-uuid element in migration data"));
+                       _("missing or malformed session-uuid element "
+                         "in migration data"));
         VIR_FREE(tmp);
         goto error;
     }
     VIR_FREE(tmp);
 
-    if (!(tmp = virXPathString("string(./uuid[1])", ctx))) {
-        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                       _("missing uuid element in migration data"));
-        goto error;
-    }
-    if (virUUIDParse(tmp, mig->uuid) < 0) {
+    if ((flags & VZ_MIGRATION_COOKIE_DOMAIN_UUID)
+        && (!(tmp = virXPathString("string(./uuid[1])", ctx))
+            || (VIR_ALLOC_N(mig->uuid, VIR_UUID_BUFLEN) < 0)
+            || (virUUIDParse(tmp, mig->uuid) < 0))) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                       _("malformed uuid element in migration data"));
+                       _("missing or malformed uuid element in migration data"));
         VIR_FREE(tmp);
         goto error;
     }
     VIR_FREE(tmp);
 
-    if (!(mig->name = virXPathString("string(./name[1])", ctx))) {
+    if ((flags & VZ_MIGRATION_COOKIE_DOMAIN_NAME)
+        && !(mig->name = virXPathString("string(./name[1])", ctx))) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                        _("missing name element in migration data"));
         goto error;
@@ -2273,7 +2300,6 @@ vzDomainMigrateBegin3Params(virDomainPtr domain,
     char *xml = NULL;
     virDomainObjPtr dom = NULL;
     vzConnPtr privconn = domain->conn->privateData;
-    vzMigrationCookiePtr mig = NULL;
 
     virCheckFlags(VZ_MIGRATION_FLAGS, NULL);
 
@@ -2292,15 +2318,11 @@ vzDomainMigrateBegin3Params(virDomainPtr domain,
     if (!(dom = vzDomObjFromDomain(domain)))
         goto cleanup;
 
-    if (VIR_ALLOC(mig) < 0)
-        goto cleanup;
-
-    if (VIR_STRDUP(mig->name, dom->def->name) < 0)
-        goto cleanup;
-
-    memcpy(mig->uuid, dom->def->uuid, VIR_UUID_BUFLEN);
-
-    if (vzBakeCookie(mig, cookieout, cookieoutlen) < 0)
+    /* session uuid is for backward compat */
+    if (vzBakeCookie(privconn->driver, dom, cookieout, cookieoutlen,
+                     VZ_MIGRATION_COOKIE_SESSION_UUID
+                     | VZ_MIGRATION_COOKIE_DOMAIN_UUID
+                     | VZ_MIGRATION_COOKIE_DOMAIN_NAME) < 0)
         goto cleanup;
 
     xml = virDomainDefFormat(dom->def, privconn->driver->caps,
@@ -2308,7 +2330,6 @@ vzDomainMigrateBegin3Params(virDomainPtr domain,
 
  cleanup:
 
-    vzMigrationCookieFree(mig);
     if (dom)
         virObjectUnlock(dom);
     return xml;
@@ -2372,12 +2393,17 @@ vzDomainMigratePrepare3Params(virConnectPtr conn,
     if (!miguri && !(*uri_out = vzMigrationCreateURI()))
         goto cleanup;
 
-    if (!(mig = vzEatCookie(cookiein, cookieinlen)))
+    if (!(mig = vzEatCookie(cookiein, cookieinlen,
+                            VZ_MIGRATION_COOKIE_DOMAIN_UUID
+                            | VZ_MIGRATION_COOKIE_DOMAIN_NAME)))
         goto cleanup;
 
-    memcpy(mig->session_uuid, privconn->driver->session_uuid, VIR_UUID_BUFLEN);
-
-    if (vzBakeCookie(mig, cookieout, cookieoutlen) < 0)
+    /* domain uuid and domain name are for backward compat */
+    if (vzBakeCookie(privconn->driver, NULL,
+                     cookieout, cookieoutlen,
+                     VZ_MIGRATION_COOKIE_SESSION_UUID
+                     | VZ_MIGRATION_COOKIE_DOMAIN_UUID
+                     | VZ_MIGRATION_COOKIE_DOMAIN_NAME) < 0)
         goto cleanup;
 
     virObjectLock(privconn->driver);
@@ -2488,7 +2514,8 @@ vzDomainMigratePerformStep(virDomainPtr domain,
         goto cleanup;
     }
 
-    if (!(mig = vzEatCookie(cookiein, cookieinlen)))
+    if (!(mig = vzEatCookie(cookiein, cookieinlen,
+                            VZ_MIGRATION_COOKIE_SESSION_UUID)))
         goto cleanup;
 
     if (!(dom = vzDomObjFromDomain(domain)))