From 56d16e614595cb903e8af803c5fca0c458a72856 Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Mon, 24 Jan 2022 16:53:27 +0100
Subject: [PATCH] qemu: domain: Add helper for generating 'fdset' ids for VM
 startup
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When starting a VM we must assign unique IDs for fdsets we add via
'-add-fd'. For now it was done by using the index of the filedescriptor
passed to the virCommand. That approach is not very flexible, because
you need to have already passed the 'fd' to virCommand before generating
the fdset path, and also won't nicely work with fdsets containing two or
more fds.

This patch introduces a counter into the private data of a qemu domain
so that we can allocate unique ids without relying on virCommand.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
---
 src/qemu/qemu_domain.c | 29 +++++++++++++++++++++++++++++
 src/qemu/qemu_domain.h |  5 +++++
 2 files changed, 34 insertions(+)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index ee1cf6f9bb..c096e5bb9a 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -683,6 +683,33 @@ qemuDomainStorageIDReset(qemuDomainObjPrivate *priv)
 }
 
 
+/**
+ * qemuDomainFDSetIDNew:
+ * @priv: qemu VM private data object.
+ *
+ * Generate a new unique id for a fdset. Note that this is necessary only for
+ * startup. When running qemu auto-assigns id for added fdset.
+ */
+unsigned int
+qemuDomainFDSetIDNew(qemuDomainObjPrivate *priv)
+{
+    return priv->fdsetindex++;
+}
+
+
+/**
+ * qemuDomainFDSetIDReset:
+ * @priv: qemu VM private data object.
+ *
+ * Resets the data for the fdset ID generator.
+ */
+static void
+qemuDomainFDSetIDReset(qemuDomainObjPrivate *priv)
+{
+    priv->fdsetindex = 0;
+}
+
+
 static void
 qemuDomainSecretInfoClear(qemuDomainSecretInfo *secinfo,
                           bool keepAlias)
@@ -1683,6 +1710,8 @@ qemuDomainObjPrivateDataClear(qemuDomainObjPrivate *priv)
     /* reset node name allocator */
     qemuDomainStorageIDReset(priv);
 
+    qemuDomainFDSetIDReset(priv);
+
     priv->dbusDaemonRunning = false;
 
     if (priv->dbusVMStateIds)
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 0a9d312b65..52b500f294 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -207,6 +207,9 @@ struct _qemuDomainObjPrivate {
     /* counter for generating node names for qemu disks */
     unsigned long long nodenameindex;
 
+    /* counter for generating IDs of fdsets - only relevant during startup */
+    unsigned int fdsetindex;
+
     /* qemuProcessStartCPUs stores the reason for starting vCPUs here for the
      * RESUME event handler to use it */
     virDomainRunningReason runningReason;
@@ -969,6 +972,8 @@ char * qemuDomainGetManagedPRSocketPath(qemuDomainObjPrivate *priv);
 
 bool qemuDomainDefHasManagedPR(virDomainObj *vm);
 
+unsigned int qemuDomainFDSetIDNew(qemuDomainObjPrivate *priv);
+
 virDomainEventResumedDetailType
 qemuDomainRunningReasonToResumeEvent(virDomainRunningReason reason);