SERVER-4999 Normalize all hostnames to lowercase

Hostnames passed to replSetInitiate, replSetReconfig, addShard, etc. are
all normalized by replacing ASCII uppercase characters with lowercase
characters, consistent with how MongoDB drivers treat hostnames.

The shell's getHostName() function now returns the hostname lowercased.

Fixes undefined behavior in mongo::str::toLower().

2 files changed, 10 insertions, 3 deletions

diff --git a/src/mongo/shell/replsettest.js b/src/mongo/shell/replsettest.js
index df1009e0d66..565fd3fb7b5 100644
--- a/src/mongo/shell/replsettest.js
+++ b/src/mongo/shell/replsettest.js
@@ -279,7 +279,8 @@ var ReplSetTest = function(opts) {
                           "/" + node.name);
                 }
 
-                if (status.members[i].name == node.host || status.members[i].name == node.name) {
+                if (status.members[i].name.toLowerCase() == node.host.toLowerCase() ||
+                    status.members[i].name.toLowerCase() == node.name.toLowerCase()) {
                     for (var j = 0; j < states.length; j++) {
                         if (printStatus) {
                             print("Status -- " + " current state: " + status.members[i][ind] +
@@ -2597,7 +2598,7 @@ var ReplSetTest = function(opts) {
         print('Starting new replica set ' + self.name);
 
         self.useHostName = opts.useHostName == undefined ? true : opts.useHostName;
-        self.host = self.useHostName ? (opts.host || getHostName()) : 'localhost';
+        self.host = (self.useHostName ? (opts.host || getHostName()) : 'localhost').toLowerCase();
         self.oplogSize = opts.oplogSize || 40;
         self.useSeedList = opts.useSeedList || false;
         self.keyFile = opts.keyFile;
@@ -2693,7 +2694,7 @@ var ReplSetTest = function(opts) {
         self.ports = existingNodes.map(node => node.split(':')[1]);
         self.nodes = existingNodes.map(node => new Mongo(node));
         self.waitForKeys = false;
-        self.host = existingNodes[0].split(':')[0];
+        self.host = existingNodes[0].split(':')[0].toLowerCase();
         self.name = conf._id;
     }
 
diff --git a/src/mongo/shell/shell_utils_extended.cpp b/src/mongo/shell/shell_utils_extended.cpp
index 2db4d7713a3..dadf2300eae 100644
--- a/src/mongo/shell/shell_utils_extended.cpp
+++ b/src/mongo/shell/shell_utils_extended.cpp
@@ -38,6 +38,7 @@
 
 #include <boost/filesystem.hpp>
 #include <fstream>
+#include <string>
 
 #include "mongo/scripting/engine.h"
 #include "mongo/shell/shell_utils.h"
@@ -330,11 +331,16 @@ BSONObj writeFile(const BSONObj& args, void* data) {
     return undefinedReturn;
 }
 
+// Return hostname normalized to lowercase for ease of use in tests.
 BSONObj getHostName(const BSONObj& a, void* data) {
     uassert(13411, "getHostName accepts no arguments", a.nFields() == 0);
     char buf[260];  // HOST_NAME_MAX is usually 255
     verify(gethostname(buf, 260) == 0);
     buf[259] = '\0';
+    for (char* c = buf; *c; c++) {
+        *c = static_cast<char>(tolower(static_cast<unsigned char>(*c)));
+    }
+
     return BSON("" << buf);
 }