SERVER-10886 Create function to override rawOut destination stream to avoid corrupting tool output

3 files changed, 31 insertions, 2 deletions

diff --git a/src/mongo/tools/tool_logger.cpp b/src/mongo/tools/tool_logger.cpp
index 619fd7c36ca..1661c5f9fe1 100644
--- a/src/mongo/tools/tool_logger.cpp
+++ b/src/mongo/tools/tool_logger.cpp
@@ -26,6 +26,7 @@
 #include "mongo/logger/message_event.h"
 #include "mongo/logger/message_event_utf8_encoder.h"
 #include "mongo/tools/tool_options.h"
+#include "mongo/util/log.h"
 
 namespace mongo {
 namespace {
@@ -88,6 +89,8 @@ MONGO_INITIALIZER_GENERAL(ToolLogRedirection,
         logger::globalLogDomain()->attachAppender(MessageLogDomain::AppenderAutoPtr(
                     new ConsoleAppender<MessageEventEphemeral, ErrorConsole>(
                         new MessageEventDetailsEncoder)));
+
+        setRawOutDestination(stderr);
     }
 
     // Only put an appender on our informational messages if we did not use --quiet
diff --git a/src/mongo/util/log.cpp b/src/mongo/util/log.cpp
index b778b8cc006..ae24f924ffb 100644
--- a/src/mongo/util/log.cpp
+++ b/src/mongo/util/log.cpp
@@ -110,16 +110,30 @@ namespace mongo {
         return s.str();
     }
 
+    namespace {
+        // NOTE: We can't directly set this variable to something like "stdout" because we need to
+        // make sure that it is initialized properly before static initialization.
+        FILE *rawOutDestination = NULL;
+    } // namespace
+
+    void setRawOutDestination(FILE *outDestination) {
+        rawOutDestination = outDestination;
+    }
+
     /*
      * NOTE(schwerin): Called from signal handlers; should not be taking locks or allocating
      * memory.
      */
     void rawOut(const StringData &s) {
+        FILE* dest = rawOutDestination;
+        if (!dest) {
+            dest = stdout;
+        }
         for (size_t i = 0; i < s.size(); ++i) {
 #ifdef _WIN32
-            putc(s[i], stdout);
+            putc(s[i], dest);
 #else
-            putc_unlocked(s[i], stdout);
+            putc_unlocked(s[i], dest);
 #endif
         }
     }
diff --git a/src/mongo/util/log.h b/src/mongo/util/log.h
index 62117d519d3..f556e7708f0 100644
--- a/src/mongo/util/log.h
+++ b/src/mongo/util/log.h
@@ -129,6 +129,18 @@ namespace logger {
     string errnoWithDescription(int errorcode = -1);
     void rawOut( const StringData &s );
 
+    /*
+     * Redirects the output of "rawOut" to "outDestination".  The default is stdout.
+     *
+     * NOTE: This needs to be here because the tools such as mongoexport and mongodump sometimes
+     * send data to stdout and share this code, so they need to be able to redirect output to
+     * stderr.  Eventually rawOut should be replaced with something better and our tools should not
+     * need to call internal server shutdown functions.
+     *
+     * NOTE: This function is not thread safe and should not be called from a multithreaded context.
+     */
+    void setRawOutDestination(FILE *outDestination);
+
     /**
      * Write the current context (backtrace), along with the optional "msg".
      */