Merge #11592: 0.15: Backportsv0.15.1rc1

8195cb0d7 rpc: further constrain the libevent workaround (Cory Fields)
34153a7e4 rpc: work-around an upstream libevent bug (Cory Fields)
fc308a6cd Add unit test for stale tip checking (Suhas Daftuar)
2ed0647ac Add CConnmanTest to mutate g_connman in tests (João Barbosa)
a607a95d8 Connect to an extra outbound peer if our tip is stale (Suhas Daftuar)
459f2db42 Track tip update time and last new block announcement from each peer (Suhas Daftuar)
49bf09018 net: Allow connecting to extra outbound peers (Suhas Daftuar)
bb83fe190 Add release notes describing blockmaxweight deprecation (Matt Corallo)
4c82cea99 Use a sensible default for blockmaxweight (Matt Corallo)
7871a7d3b Deprecate confusing blockmaxsize, fix getmininginfo output (Matt Corallo)
6baa317b5 Fix minchainwork test for 0.15 backport (Suhas Daftuar)
55b7abfa8 Make p2p-acceptablock not an extended test (Matt Corallo)
5bec7744d [qa] test that invalid blocks on an invalid chain get a disconnect (Matt Corallo)
92d6105c4 Reject headers building on invalid chains by tracking invalidity (Matt Corallo)
51001d684 Accept unrequested blocks with work equal to our tip (Matt Corallo)
c6e4d0ce8 Stop always storing blocks from whitelisted peers (Matt Corallo)
e976c36dd Rewrite p2p-acceptblock in preparation for slight behavior changes (Matt Corallo)
ec8dedff4 net: Add missing lock in ProcessHeadersMessage(...) (practicalswift)
59b210d9a Disconnect outbound peers relaying invalid headers (Suhas Daftuar)
fc966bbd2 moveonly: factor out headers processing into separate function (Suhas Daftuar)
e3272242e Add unit test for outbound peer eviction (Suhas Daftuar)
9961abf9e Permit disconnection of outbound peers on bad/slow chains (Suhas Daftuar)
bf191a718 Disconnecting from bad outbound peers in IBD (Suhas Daftuar)
d570aa429 Fix uninitialized g_connman crash in Shutdown() (MeshCollider)
0a5477c7e net: stop both net/net_processing before destroying them (Cory Fields)
b4136f21c net: drop unused connman param (Cory Fields)
dc897e53d net: use an interface class rather than signals for message processing (Cory Fields)
8aee55af3 net: pass CConnman via pointer rather than reference (Cory Fields)
6f279652b Rename fAddnode to a more-descriptive "manual_connection" (Matt Corallo)
ffb6ea4e5 Add comment explaining forced processing of compact blocks (Suhas Daftuar)
2df65eeb9 qa: add test for minchainwork use in acceptblock (Suhas Daftuar)
3acec3878 Don't process unrequested, low-work blocks (Suhas Daftuar)
0e9d04bf0 [qa] Test nMinimumChainWork (Suhas Daftuar)
da4908c3a Allow setting nMinimumChainWork on command line (Suhas Daftuar)
41088795d qa: Remove never used return value of sync_with_ping (MarcoFalke)
f3457d0e8 qa: Make tmpdir option an absolute path (MarcoFalke)
9c8006dc3 Avoid opening copied wallet databases simultaneously (Russell Yanofsky)
de7053f11 [wallet] Fix leak in CDB constructor (João Barbosa)
fd79ed6b2 Ensure backupwallet fails when attempting to backup to source file (Tomas van der Wansem)
d94fc336c scripted-diff: rename assert_raises_jsonrpc to assert_raises_rpc error (John Newbery)
623de0acb [tests] do not allow assert_raises_message to be called with JSONRPCException (John Newbery)
5b728c8e9 [tests] remove direct testing on JSONRPCException from individual test cases (John Newbery)

Pull request description:

Tree-SHA512: 9fdb5c47844a899271023d8d445f7fc728e3ad71916490cd9783464684967594b07cda05dd644b722bfcea9fade74d06cfc501e1a68abf118d6d03fbbf7d7707

2 files changed, 57 insertions, 19 deletions

diff --git a/src/wallet/db.cpp b/src/wallet/db.cpp
index d2fe4866fa..fb6e576074 100644
--- a/src/wallet/db.cpp
+++ b/src/wallet/db.cpp
@@ -20,6 +20,40 @@
 
 #include <boost/thread.hpp>
 
+namespace {
+//! Make sure database has a unique fileid within the environment. If it
+//! doesn't, throw an error. BDB caches do not work properly when more than one
+//! open database has the same fileid (values written to one database may show
+//! up in reads to other databases).
+//!
+//! BerkeleyDB generates unique fileids by default
+//! (https://docs.oracle.com/cd/E17275_01/html/programmer_reference/program_copy.html),
+//! so bitcoin should never create different databases with the same fileid, but
+//! this error can be triggered if users manually copy database files.
+void CheckUniqueFileid(const CDBEnv& env, const std::string& filename, Db& db)
+{
+    if (env.IsMock()) return;
+
+    u_int8_t fileid[DB_FILE_ID_LEN];
+    int ret = db.get_mpf()->get_fileid(fileid);
+    if (ret != 0) {
+        throw std::runtime_error(strprintf("CDB: Can't open database %s (get_fileid failed with %d)", filename, ret));
+    }
+
+    for (const auto& item : env.mapDb) {
+        u_int8_t item_fileid[DB_FILE_ID_LEN];
+        if (item.second && item.second->get_mpf()->get_fileid(item_fileid) == 0 &&
+            memcmp(fileid, item_fileid, sizeof(fileid)) == 0) {
+            const char* item_filename = nullptr;
+            item.second->get_dbname(&item_filename, nullptr);
+            throw std::runtime_error(strprintf("CDB: Can't open database %s (duplicates fileid %s from %s)", filename,
+                HexStr(std::begin(item_fileid), std::end(item_fileid)),
+                item_filename ? item_filename : "(unknown database)"));
+        }
+    }
+}
+} // namespace
+
 //
 // CDB
 //
@@ -379,35 +413,34 @@ CDB::CDB(CWalletDBWrapper& dbw, const char* pszMode, bool fFlushOnCloseIn) : pdb
         if (!env->Open(GetDataDir()))
             throw std::runtime_error("CDB: Failed to open database environment.");
 
-        strFile = strFilename;
-        ++env->mapFileUseCount[strFile];
-        pdb = env->mapDb[strFile];
+        pdb = env->mapDb[strFilename];
         if (pdb == nullptr) {
             int ret;
-            pdb = new Db(env->dbenv, 0);
+            std::unique_ptr<Db> pdb_temp(new Db(env->dbenv, 0));
 
             bool fMockDb = env->IsMock();
             if (fMockDb) {
-                DbMpoolFile* mpf = pdb->get_mpf();
+                DbMpoolFile* mpf = pdb_temp->get_mpf();
                 ret = mpf->set_flags(DB_MPOOL_NOFILE, 1);
-                if (ret != 0)
-                    throw std::runtime_error(strprintf("CDB: Failed to configure for no temp file backing for database %s", strFile));
+                if (ret != 0) {
+                    throw std::runtime_error(strprintf("CDB: Failed to configure for no temp file backing for database %s", strFilename));
+                }
             }
 
-            ret = pdb->open(nullptr,                               // Txn pointer
-                            fMockDb ? nullptr : strFile.c_str(),   // Filename
-                            fMockDb ? strFile.c_str() : "main", // Logical db name
-                            DB_BTREE,                           // Database type
-                            nFlags,                             // Flags
+            ret = pdb_temp->open(nullptr,                             // Txn pointer
+                            fMockDb ? nullptr : strFilename.c_str(),  // Filename
+                            fMockDb ? strFilename.c_str() : "main",   // Logical db name
+                            DB_BTREE,                                 // Database type
+                            nFlags,                                   // Flags
                             0);
 
             if (ret != 0) {
-                delete pdb;
-                pdb = nullptr;
-                --env->mapFileUseCount[strFile];
-                strFile = "";
                 throw std::runtime_error(strprintf("CDB: Error %d, can't open database %s", ret, strFilename));
             }
+            CheckUniqueFileid(*env, strFilename, *pdb_temp);
+
+            pdb = pdb_temp.release();
+            env->mapDb[strFilename] = pdb;
 
             if (fCreate && !Exists(std::string("version"))) {
                 bool fTmp = fReadOnly;
@@ -415,9 +448,9 @@ CDB::CDB(CWalletDBWrapper& dbw, const char* pszMode, bool fFlushOnCloseIn) : pdb
                 WriteVersion(CLIENT_VERSION);
                 fReadOnly = fTmp;
             }
-
-            env->mapDb[strFile] = pdb;
         }
+        ++env->mapFileUseCount[strFilename];
+        strFile = strFilename;
     }
 }
 
@@ -673,6 +706,11 @@ bool CWalletDBWrapper::Backup(const std::string& strDest)
                     pathDest /= strFile;
 
                 try {
+                    if (fs::equivalent(pathSrc, pathDest)) {
+                        LogPrintf("cannot backup to wallet source file %s\n", pathDest.string());
+                        return false;
+                    }
+
                     fs::copy_file(pathSrc, pathDest, fs::copy_option::overwrite_if_exists);
                     LogPrintf("copied %s to %s\n", strFile, pathDest.string());
                     return true;
diff --git a/src/wallet/db.h b/src/wallet/db.h
index 3614e34fbb..6f3cfe9557 100644
--- a/src/wallet/db.h
+++ b/src/wallet/db.h
@@ -45,7 +45,7 @@ public:
     void Reset();
 
     void MakeMock();
-    bool IsMock() { return fMockDb; }
+    bool IsMock() const { return fMockDb; }
 
     /**
      * Verify that database file strFile is OK. If it is not,