From 03afd10cd38f2906fb475e6a6c0165a0ef9dc2c3 Mon Sep 17 00:00:00 2001
From: Jonathon Jongsma <jjongsma@redhat.com>
Date: Thu, 21 Jul 2022 17:16:40 -0500
Subject: [PATCH] qemu: expand nbdkit capabilities

In order to add caching of the nbdkit capabilities, we will need to
compare against file modification times, etc. So look up this
information when creating the nbdkit caps.

Add a nbdkit_moddir build option to allow the builder to specify the
location to look for nbdkit plugins and filters.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
---
 src/qemu/qemu_nbdkit.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/src/qemu/qemu_nbdkit.c b/src/qemu/qemu_nbdkit.c
index e4e8fd568e..58828dd89a 100644
--- a/src/qemu/qemu_nbdkit.c
+++ b/src/qemu/qemu_nbdkit.c
@@ -20,6 +20,7 @@
 #include <config.h>
 #include <glib.h>
 
+#include "configmake.h"
 #include "vircommand.h"
 #include "virerror.h"
 #include "virlog.h"
@@ -38,6 +39,10 @@
 
 VIR_LOG_INIT("qemu.nbdkit");
 
+#define NBDKIT_MODDIR LIBDIR "/nbdkit"
+#define NBDKIT_PLUGINDIR NBDKIT_MODDIR "/plugins"
+#define NBDKIT_FILTERDIR NBDKIT_MODDIR "/filters"
+
 VIR_ENUM_IMPL(qemuNbdkitCaps,
     QEMU_NBDKIT_CAPS_LAST,
     /* 0 */
@@ -51,6 +56,11 @@ struct _qemuNbdkitCaps {
 
     char *path;
     char *version;
+    time_t ctime;
+    time_t libvirtCtime;
+    time_t pluginDirMtime;
+    time_t filterDirMtime;
+    unsigned int libvirtVersion;
 
     virBitmap *flags;
 };
@@ -175,9 +185,41 @@ qemuNbdkitCapsNew(const char *path)
 }
 
 
+static time_t
+qemuNbdkitGetDirMtime(const char *moddir)
+{
+    struct stat st;
+
+    if (stat(moddir, &st) < 0) {
+        VIR_DEBUG("Failed to stat nbdkit module directory '%s': %s",
+                  moddir,
+                  g_strerror(errno));
+        return 0;
+    }
+
+    return st.st_mtime;
+}
+
+
 G_GNUC_UNUSED static void
 qemuNbdkitCapsQuery(qemuNbdkitCaps *caps)
 {
+    struct stat st;
+
+    if (stat(caps->path, &st) < 0) {
+        VIR_DEBUG("Failed to stat nbdkit binary '%s': %s",
+                  caps->path,
+                  g_strerror(errno));
+        caps->ctime  = 0;
+        return;
+    }
+
+    caps->ctime = st.st_ctime;
+    caps->filterDirMtime = qemuNbdkitGetDirMtime(NBDKIT_FILTERDIR);
+    caps->pluginDirMtime = qemuNbdkitGetDirMtime(NBDKIT_PLUGINDIR);
+    caps->libvirtCtime = virGetSelfLastChanged();
+    caps->libvirtVersion = LIBVIR_VERSION_NUMBER;
+
     qemuNbdkitCapsQueryPlugins(caps);
     qemuNbdkitCapsQueryFilters(caps);
     qemuNbdkitCapsQueryVersion(caps);