Auto merge of #1374 - str4d:1106-alert-safe-mode, r=str4d

Enable high-priority alerts to put the RPC into safe mode

This reverts the changes in 986b5e257e and adds a priority check.

Continuation of #1337
Closes #1106

src/alert.cpp

@@ -41,7 +41,7 @@ void CUnsignedAlert::SetNull()
 
     strComment.clear();
     strStatusBar.clear();
-    strReserved.clear();
+    strRPCError.clear();
 }
 
 std::string CUnsignedAlert::ToString() const
@@ -66,6 +66,7 @@ std::string CUnsignedAlert::ToString() const
         "    nPriority    = %d\n"
         "    strComment   = \"%s\"\n"
         "    strStatusBar = \"%s\"\n"
+        "    strRPCError  = \"%s\"\n"
         ")\n",
         nVersion,
         nRelayUntil,
@@ -78,7 +79,8 @@ std::string CUnsignedAlert::ToString() const
         strSetSubVer,
         nPriority,
         strComment,
-        strStatusBar);
+        strStatusBar,
+        strRPCError);
 }
 
 void CAlert::SetNull()

src/alert.h

@@ -44,7 +44,7 @@ public:
     // Actions
     std::string strComment;
     std::string strStatusBar;
-    std::string strReserved;
+    std::string strRPCError;
 
     ADD_SERIALIZE_METHODS;
 
@@ -64,7 +64,7 @@ public:
 
         READWRITE(LIMITED_STRING(strComment, 65536));
         READWRITE(LIMITED_STRING(strStatusBar, 256));
-        READWRITE(LIMITED_STRING(strReserved, 256));
+        READWRITE(LIMITED_STRING(strRPCError, 256));
     }
 
     void SetNull();

src/main.cpp

@@ -4071,6 +4071,9 @@ string GetWarnings(string strFor)
             {
                 nPriority = alert.nPriority;
                 strStatusBar = alert.strStatusBar;
+                if (alert.nPriority >= ALERT_PRIORITY_SAFE_MODE) {
+                    strRPC = alert.strRPCError;
+                }
             }
         }
     }

src/main.h

@@ -54,6 +54,8 @@ static const unsigned int DEFAULT_BLOCK_MIN_SIZE = 0;
 static const unsigned int DEFAULT_BLOCK_PRIORITY_SIZE = 50000;
 /** Default for accepting alerts from the P2P network. */
 static const bool DEFAULT_ALERTS = true;
+/** Minimum alert priority for enabling safe mode. */
+static const int ALERT_PRIORITY_SAFE_MODE = 4000;
 /** The maximum size for transactions we're willing to relay/mine */
 static const unsigned int MAX_STANDARD_TX_SIZE = 100000;
 /** Maximum number of signature check operations in an IsStandard() P2SH script */

src/sendalert.cpp

@@ -85,9 +85,11 @@ void ThreadSendAlert()
     //  1000 for Misc warnings like out of disk space and clock is wrong
     //  2000 for longer invalid proof-of-work chain 
     //  Higher numbers mean higher priority
+    //  4000 or higher will put the RPC into safe mode
     alert.nPriority     = 5000;
     alert.strComment    = "";
     alert.strStatusBar  = "URGENT: Upgrade required: see https://z.cash";
+    alert.strRPCError   = "URGENT: Upgrade required: see https://z.cash";
 
     // Set specific client version/versions here. If setSubVer is empty, no filtering on subver is done:
     // alert.setSubVer.insert(std::string("/Satoshi:0.7.2/"));

src/test/alert_tests.cpp

@@ -13,6 +13,8 @@
 #include "data/alertTests.raw.h"
 
 #include "main.h"
+#include "rpcprotocol.h"
+#include "rpcserver.h"
 #include "serialize.h"
 #include "streams.h"
 #include "util.h"
@@ -25,6 +27,7 @@
 #include <boost/filesystem/operations.hpp>
 #include <boost/foreach.hpp>
 #include <boost/test/unit_test.hpp>
+#include "json/json_spirit_reader_template.h"
 
 #include "key.h"
 #include "alertkeys.h"
@@ -182,9 +185,22 @@ void GenerateAlertTests()
     ++alert.nID;
     SignAndSerialize(alert, sBuffer);
 
+    ++alert.nID;
+    alert.nPriority = 5000;
+    alert.strStatusBar  = "Alert 3, disables RPC";
+    alert.strRPCError = "RPC disabled";
+    SignAndSerialize(alert, sBuffer);
+
+    ++alert.nID;
+    alert.nPriority = 5000;
+    alert.strStatusBar  = "Alert 4, re-enables RPC";
+    alert.strRPCError = "";
+    SignAndSerialize(alert, sBuffer);
+
     ++alert.nID;
     alert.nMinVer = 11;
     alert.nMaxVer = 22;
+    alert.nPriority = 100;
     SignAndSerialize(alert, sBuffer);
 
     ++alert.nID;
@@ -320,7 +336,7 @@ BOOST_AUTO_TEST_CASE(AlertNotify)
         alert.ProcessAlert(alertKey, false);
 
     std::vector<std::string> r = read_lines(temp);
-    BOOST_CHECK_EQUAL(r.size(), 4u);
+    BOOST_CHECK_EQUAL(r.size(), 6u);
 
 // Windows built-in echo semantics are different than posixy shells. Quotes and
 // whitespace are printed literally.
@@ -329,16 +345,43 @@ BOOST_AUTO_TEST_CASE(AlertNotify)
     BOOST_CHECK_EQUAL(r[0], "Alert 1");
     BOOST_CHECK_EQUAL(r[1], "Alert 2, cancels 1");
     BOOST_CHECK_EQUAL(r[2], "Alert 2, cancels 1");
-    BOOST_CHECK_EQUAL(r[3], "Evil Alert; /bin/ls; echo "); // single-quotes should be removed
+    BOOST_CHECK_EQUAL(r[3], "Alert 3, disables RPC");
+    BOOST_CHECK_EQUAL(r[4], "Alert 4, reenables RPC"); // dashes should be removed
+    BOOST_CHECK_EQUAL(r[5], "Evil Alert; /bin/ls; echo "); // single-quotes should be removed
 #else
     BOOST_CHECK_EQUAL(r[0], "'Alert 1' ");
     BOOST_CHECK_EQUAL(r[1], "'Alert 2, cancels 1' ");
     BOOST_CHECK_EQUAL(r[2], "'Alert 2, cancels 1' ");
-    BOOST_CHECK_EQUAL(r[3], "'Evil Alert; /bin/ls; echo ' ");
+    BOOST_CHECK_EQUAL(r[3], "'Alert 3, disables RPC' ");
+    BOOST_CHECK_EQUAL(r[4], "'Alert 4, reenables RPC' "); // dashes should be removed
+    BOOST_CHECK_EQUAL(r[5], "'Evil Alert; /bin/ls; echo ' ");
 #endif
     boost::filesystem::remove(temp);
 
     SetMockTime(0);
+    mapAlerts.clear();
+}
+
+BOOST_AUTO_TEST_CASE(AlertDisablesRPC)
+{
+    SetMockTime(11);
+    const std::vector<unsigned char>& alertKey = Params(CBaseChainParams::MAIN).AlertKey();
+
+    // Command should work before alerts
+    BOOST_CHECK_EQUAL(GetWarnings("rpc"), "");
+
+    // First alert should disable RPC
+    alerts[5].ProcessAlert(alertKey, false);
+    BOOST_CHECK_EQUAL(alerts[5].strRPCError, "RPC disabled");
+    BOOST_CHECK_EQUAL(GetWarnings("rpc"), "RPC disabled");
+
+    // Second alert should re-enable RPC
+    alerts[6].ProcessAlert(alertKey, false);
+    BOOST_CHECK_EQUAL(alerts[6].strRPCError, "");
+    BOOST_CHECK_EQUAL(GetWarnings("rpc"), "");
+
+    SetMockTime(0);
+    mapAlerts.clear();
 }
 
 static bool falseFunc() { return false; }