SERVER-22364 threadsafe errno printing, pidfile error fix

If the errno is set after a pidfile write failure, then it will get
printed, otherwise this will print "Unable to determine OS error".

1 files changed, 10 insertions, 5 deletions

diff --git a/src/mongo/util/processinfo.cpp b/src/mongo/util/processinfo.cpp
index 5a0e8dc798c..8afcb2f0eeb 100644
--- a/src/mongo/util/processinfo.cpp
+++ b/src/mongo/util/processinfo.cpp
@@ -58,6 +58,15 @@ public:
         path = p;
         ofstream out(path.c_str(), ios_base::out);
         out << ProcessId::getCurrent() << endl;
+        if (!out.good()) {
+            auto errAndStr = errnoAndDescription();
+            if (errAndStr.first == 0) {
+                log() << "ERROR: Cannot write pid file to " << path
+                      << ": Unable to determine OS error";
+            } else {
+                log() << "ERROR: Cannot write pid file to " << path << ": " << errAndStr.second;
+            }
+        }
         return out.good();
     }
 
@@ -65,11 +74,7 @@ public:
 } pidFileWiper;
 
 bool writePidFile(const string& path) {
-    bool e = pidFileWiper.write(path);
-    if (!e) {
-        log() << "ERROR: Cannot write pid file to " << path << ": " << strerror(errno);
-    }
-    return e;
+    return pidFileWiper.write(path);
 }
 
 ProcessInfo::SystemInfo* ProcessInfo::systemInfo = NULL;