[libvirt] [PATCH] qemu: Don't overwrite errors by closefd in error paths

[Jiri Denemark]

When qemuMonitorCloseFileHandle is called in error path, we need to
preserve the original error since a possible further error when running
closefd monitor command is not very useful to users.
---
 src/qemu/qemu_monitor.c |   34 +++++++++++++++++++++++++---------
 src/qemu/qemu_monitor.h |    3 ++-
 2 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index e593642..4c6c66f 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -1552,7 +1552,7 @@ int qemuMonitorMigrateToFd(qemuMonitorPtr mon,
         ret = qemuMonitorTextMigrate(mon, flags, "fd:migrate");
 
     if (ret < 0) {
-        if (qemuMonitorCloseFileHandle(mon, "migrate") < 0)
+        if (qemuMonitorCloseFileHandle(mon, "migrate", true) < 0)
             VIR_WARN("failed to close migration handle");
     }
 
@@ -1962,22 +1962,34 @@ int qemuMonitorSendFileHandle(qemuMonitorPtr mon,
 
 
 int qemuMonitorCloseFileHandle(qemuMonitorPtr mon,
-                               const char *fdname)
+                               const char *fdname,
+                               bool preserveError)
 {
-    int ret;
+    int ret = -1;
+    virErrorPtr error = NULL;
+
     VIR_DEBUG("mon=%p fdname=%s",
           mon, fdname);
 
+    if (preserveError)
+        error = virSaveLastError();
+
     if (!mon) {
         qemuReportError(VIR_ERR_INVALID_ARG, "%s",
                         _("monitor must not be NULL"));
-        return -1;
+        goto cleanup;
     }
 
     if (mon->json)
         ret = qemuMonitorJSONCloseFileHandle(mon, fdname);
     else
         ret = qemuMonitorTextCloseFileHandle(mon, fdname);
+
+cleanup:
+    if (error) {
+        virSetError(error);
+        virFreeError(error);
+    }
     return ret;
 }
 
@@ -2014,9 +2026,11 @@ int qemuMonitorAddHostNetwork(qemuMonitorPtr mon,
 
 cleanup:
     if (ret < 0) {
-        if (tapfd >= 0 && qemuMonitorCloseFileHandle(mon, tapfd_name) < 0)
+        if (tapfd >= 0 &&
+            qemuMonitorCloseFileHandle(mon, tapfd_name, true) < 0)
             VIR_WARN("failed to close device handle '%s'", tapfd_name);
-        if (vhostfd >= 0 && qemuMonitorCloseFileHandle(mon, vhostfd_name) < 0)
+        if (vhostfd >= 0 &&
+            qemuMonitorCloseFileHandle(mon, vhostfd_name, true) < 0)
             VIR_WARN("failed to close device handle '%s'", vhostfd_name);
     }
 
@@ -2078,9 +2092,11 @@ int qemuMonitorAddNetdev(qemuMonitorPtr mon,
 
 cleanup:
     if (ret < 0) {
-        if (tapfd >= 0 && qemuMonitorCloseFileHandle(mon, tapfd_name) < 0)
+        if (tapfd >= 0 &&
+            qemuMonitorCloseFileHandle(mon, tapfd_name, true) < 0)
             VIR_WARN("failed to close device handle '%s'", tapfd_name);
-        if (vhostfd >= 0 && qemuMonitorCloseFileHandle(mon, vhostfd_name) < 0)
+        if (vhostfd >= 0 &&
+            qemuMonitorCloseFileHandle(mon, vhostfd_name, true) < 0)
             VIR_WARN("failed to close device handle '%s'", vhostfd_name);
     }
 
@@ -2258,7 +2274,7 @@ int qemuMonitorAddDeviceWithFd(qemuMonitorPtr mon,
         ret = qemuMonitorTextAddDevice(mon, devicestr);
 
     if (ret < 0 && fd >= 0) {
-        if (qemuMonitorCloseFileHandle(mon, fdname) < 0)
+        if (qemuMonitorCloseFileHandle(mon, fdname, true) < 0)
             VIR_WARN("failed to close device handle '%s'", fdname);
     }
 
diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
index 893f3e9..71ee932 100644
--- a/src/qemu/qemu_monitor.h
+++ b/src/qemu/qemu_monitor.h
@@ -363,7 +363,8 @@ int qemuMonitorSendFileHandle(qemuMonitorPtr mon,
                               int fd);
 
 int qemuMonitorCloseFileHandle(qemuMonitorPtr mon,
-                               const char *fdname);
+                               const char *fdname,
+                               bool preserveError);
 
 
 /* XXX do we really want to hardcode 'netstr' as the
-- 
1.7.6