[libvirt PATCH v8 14/37] qemu: log error output from nbdkit

[Jonathon Jongsma]

log stderr and stdout from nbdkit into its own log so that
nbdkit-related issues can be debugged more easily.

Signed-off-by: Jonathon Jongsma <jjong...@redhat.com>
Reviewed-by: Peter Krempa <pkre...@redhat.com>
---
 src/qemu/qemu_nbdkit.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_nbdkit.c b/src/qemu/qemu_nbdkit.c
index 6bf962d0f1..2d70e72c42 100644
--- a/src/qemu/qemu_nbdkit.c
+++ b/src/qemu/qemu_nbdkit.c
@@ -852,12 +852,23 @@ qemuNbdkitProcessStart(qemuNbdkitProcess *proc,
     virTimeBackOffVar timebackoff;
     g_autoptr(virURI) uri = NULL;
     g_autofree char *uristring = NULL;
+    g_autofree char *basename = g_strdup_printf("%s-nbdkit-%i", vm->def->name, 
proc->source->id);
+    int logfd = -1;
+    g_autoptr(qemuLogContext) logContext = NULL;
 
     if (!(cmd = qemuNbdkitProcessBuildCommand(proc)))
         return -1;
 
+    if (!(logContext = qemuLogContextNew(driver, vm, basename))) {
+        virLastErrorPrefixMessage("%s", _("can't connect to virtlogd"));
+        return -1;
+    }
+
+    logfd = qemuLogContextGetWriteFD(logContext);
+
     VIR_DEBUG("starting nbdkit process for %s", proc->source->nodestorage);
-    virCommandSetErrorBuffer(cmd, &errbuf);
+    virCommandSetErrorFD(cmd, &logfd);
+    virCommandSetOutputFD(cmd, &logfd);
     virCommandSetPidFile(cmd, proc->pidfile);
 
     if (qemuExtDeviceLogCommand(driver, vm, cmd, "nbdkit") < 0)
@@ -899,6 +910,9 @@ qemuNbdkitProcessStart(qemuNbdkitProcess *proc,
     if ((uri = qemuBlockStorageSourceGetURI(proc->source)))
         uristring = virURIFormat(uri);
 
+    if (qemuLogContextReadFiltered(logContext, &errbuf, 1024) < 0)
+        VIR_WARN("Unable to read from nbdkit log");
+
     virReportError(VIR_ERR_OPERATION_FAILED,
                    _("Failed to connect to nbdkit for '%1$s': %2$s"),
                    NULLSTR(uristring), NULLSTR(errbuf));
-- 
2.41.0