File 8abd1ffe-qemu-tolerate-non-existent-files.patch of Package libvirt

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File 8abd1ffe-qemu-tolerate-non-existent-files.patch of Package libvirt (Revision 5a54f425f87666a9dac4343a8ed8b36f)

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commit 8abd1ffed18394a6212c469cb2c7b6cc28a122d2
Author: Michal Prívozník <mprivozn@redhat.com>
Date:   Thu Sep 3 18:07:43 2020 +0200

qemu_namespace: Be tolerant to non-existent files when populating /dev
    
    In 6.7.0 release I've changed how domain namespace is built and
    populated. Previously it used to be done from a pre-exec hook
    (ran in the forked off child, just before dropping all privileges
    and exec()-ing QEMU), which not only meant we had to have two
    different code paths for creating a node in domain's namespace
    (one for this pre-exec hook, the other for hotplug ran from the
    daemon), it also proved problematic because it was leaking FDs
    into QEMU process.
    
    To mitigate this problem, we've not only ditched libdevmapper
    from the NS population process, I've also dropped the pre-exec
    code and let the NS be populated from the daemon (using the
    hotplug code). But, I was not careful when doing so, because the
    pre-exec code was tolerant to files that doesn't exist, while
    this new code isn't. For instance, the very first thing that is
    done when the new NS is created is it's populated with
    @defaultDeviceACL which contain files like /dev/null, /dev/zero,
    /dev/random and /dev/kvm (and others).  While the rest will
    probably exist every time, /dev/kvm might not and thus the new
    code I wrote has to be tolerant to that.
    
    Of course, users can override the @defaultDeviceACL (by setting
    cgroup_device_acl in qemu.conf) and remove /dev/kvm (which is
    acceptable workaround), but we definitely want libvirt to work
    out of the box even on hosts without KVM.
    
    Fixes: 9048dc4e627ddf33996084167bece7b5fb83b0bc
    Reported-by: Daniel P. Berrangé <berrange@redhat.com>
    Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
    Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
    Reviewed-by: Ján Tomko <jtomko@redhat.com>

Index: libvirt-6.7.0/src/qemu/qemu_namespace.c
===================================================================
--- libvirt-6.7.0.orig/src/qemu/qemu_namespace.c
+++ libvirt-6.7.0/src/qemu/qemu_namespace.c
@@ -1094,6 +1094,9 @@ qemuNamespaceMknodItemInit(qemuNamespace
     item->file = file;
 
     if (g_lstat(file, &item->sb) < 0) {
+        if (errno == ENOENT)
+            return -2;
+
         virReportSystemError(errno,
                              _("Unable to access %s"), file);
         return -1;
@@ -1168,9 +1171,16 @@ qemuNamespacePrepareOneItem(qemuNamespac
 
     while (1) {
         qemuNamespaceMknodItem item = { 0 };
+        int rc;
 
-        if (qemuNamespaceMknodItemInit(&item, cfg, vm, next) < 0)
+        rc = qemuNamespaceMknodItemInit(&item, cfg, vm, next);
+        if (rc == -2) {
+            /* @file doesn't exist. We can break here. */
+            break;
+        } else if (rc < 0) {
+            /* Some other (critical) error. */
             return -1;
+        }
 
         if (STRPREFIX(next, QEMU_DEVPREFIX)) {
             for (i = 0; i < ndevMountsPath; i++) {

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File 8abd1ffe-qemu-tolerate-non-existent-files.patch of Package libvirt (Revision 5a54f425f87666a9dac4343a8ed8b36f)

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