[libvirt] [PATCH 2/6] virterror: Add methods to temporarily disable error reporting.

[Cole Robinson]

If error reporting is disabled, RaiseFullError will log the passed message,
but it will not wipe out the previous error and won't trigger the error
callback.

Signed-off-by: Cole Robinson <crobinso at redhat.com>
---
 src/util/virterror.c          |   82 ++++++++++++++++++++++++++++++++++-------
 src/util/virterror_internal.h |    2 +
 2 files changed, 70 insertions(+), 14 deletions(-)

diff --git a/src/util/virterror.c b/src/util/virterror.c
index 7b7543b..58b3086 100644
--- a/src/util/virterror.c
+++ b/src/util/virterror.c
@@ -26,6 +26,7 @@ virThreadLocal virThreadErrorStateIdx;
 
 typedef struct virThreadErrorState {
     virErrorPtr lastError;
+    unsigned int enableErrors;
 } virThreadErrorState;
 typedef virThreadErrorState *virThreadErrorStatePtr;
 
@@ -274,6 +275,8 @@ virThreadErrorStateObject(void)
             return NULL;
         if (VIR_ALLOC(state->lastError) < 0)
             return NULL;
+
+        state->enableErrors = 1;
         virThreadLocalSet(&virThreadErrorStateIdx, state);
     }
     return state;
@@ -289,6 +292,49 @@ virLastErrorObject(void)
     return state->lastError;
 }
 
+static unsigned int
+virGetEnableErrors(void)
+{
+    virThreadErrorStatePtr state = virThreadErrorStateObject();
+    if (!state)
+        return 1;
+
+    return state->enableErrors;
+}
+
+static void
+virSetEnableErrors(unsigned int val)
+{
+    virThreadErrorStatePtr state = virThreadErrorStateObject();
+    if (!state)
+        return;
+
+    state->enableErrors = val ? 1 : 0;
+}
+
+/*
+ * Enable error reporting and error callback launching (on by default)
+ */
+void
+virEnableErrors(void)
+{
+    virSetEnableErrors(1);
+}
+
+/*
+ * Disable error reporting and error callback launching. Calls to
+ * ReportFullError will log the message, but the previous error will remain
+ * intact.
+ *
+ * This is useful when we want to ensure that some clean up path will
+ * not stomp all over the original error report.
+ */
+void
+virDisableErrors(void)
+{
+    virSetEnableErrors(0);
+}
+
 /**
  * virGetLastError:
  *
@@ -669,21 +715,10 @@ virRaiseErrorFull(virConnectPtr conn,
     if (!to)
         return; /* Hit OOM allocating thread error object, sod all we can do now */
 
-    virResetError(to);
-
-    if (code == VIR_ERR_OK)
+    /* If code is OK, clear the previous error and return. */
+    if (code == VIR_ERR_OK) {
+        virResetError(to);
         return;
-
-    /*
-     * try to find the best place to save and report the error
-     */
-    if (conn != NULL) {
-        virMutexLock(&conn->lock);
-        if (conn->handler != NULL) {
-            handler = conn->handler;
-            userData = conn->userData;
-        }
-        virMutexUnlock(&conn->lock);
     }
 
     /*
@@ -702,6 +737,25 @@ virRaiseErrorFull(virConnectPtr conn,
     virLogMessage(virErrorDomainName(domain), virErrorLevelPriority(level),
                   funcname, linenr, 1, "%s", str);
 
+    /* Error reporting has been deliberately disabled, don't wipe out the
+     * previous error, just log what was passed and return. */
+    if (!virGetEnableErrors()) {
+        VIR_FREE(str);
+        return;
+    }
+
+    /*
+     * try to find the best place to save and report the error
+     */
+    if (conn != NULL) {
+        virMutexLock(&conn->lock);
+        if (conn->handler != NULL) {
+            handler = conn->handler;
+            userData = conn->userData;
+        }
+        virMutexUnlock(&conn->lock);
+    }
+
     /*
      * Save the information about the error
      */
diff --git a/src/util/virterror_internal.h b/src/util/virterror_internal.h
index da89de7..2f0e327 100644
--- a/src/util/virterror_internal.h
+++ b/src/util/virterror_internal.h
@@ -89,6 +89,8 @@ void virReportOOMErrorFull(virConnectPtr conn,
     virReportOOMErrorFull((conn), VIR_FROM_THIS,        \
                      __FILE__, __FUNCTION__, __LINE__)
 
+void virEnableErrors(void);
+void virDisableErrors(void);
 
 void virSetGlobalError(void);
 void virSetConnError(virConnectPtr conn);
-- 
1.6.5.1