1 files changed, 75 insertions, 18 deletions

diff --git a/src/util.cpp b/src/util.cpp
index b2023b8322..6ec7cba2ad 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -1,20 +1,14 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2016 The Bitcoin Core developers
+// Copyright (c) 2009-2017 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#if defined(HAVE_CONFIG_H)
-#include <config/bitcoin-config.h>
-#endif
-
 #include <util.h>
 
 #include <chainparamsbase.h>
-#include <fs.h>
 #include <random.h>
 #include <serialize.h>
 #include <utilstrencodings.h>
-#include <utiltime.h>
 
 #include <stdarg.h>
 
@@ -78,6 +72,7 @@
 
 #include <boost/algorithm/string/case_conv.hpp> // for to_lower()
 #include <boost/algorithm/string/predicate.hpp> // for startswith() and endswith()
+#include <boost/interprocess/sync/file_lock.hpp>
 #include <boost/program_options/detail/config_file.hpp>
 #include <boost/thread.hpp>
 #include <openssl/crypto.h>
@@ -89,6 +84,7 @@ const int64_t nStartupTime = GetTime();
 
 const char * const BITCOIN_CONF_FILENAME = "bitcoin.conf";
 const char * const BITCOIN_PID_FILENAME = "bitcoind.pid";
+const char * const DEFAULT_DEBUGLOGFILE = "debug.log";
 
 ArgsManager gArgs;
 bool fPrintToConsole = false;
@@ -189,26 +185,40 @@ static void DebugPrintInit()
     vMsgsBeforeOpenLog = new std::list<std::string>;
 }
 
-void OpenDebugLog()
+fs::path GetDebugLogPath()
+{
+    fs::path logfile(gArgs.GetArg("-debuglogfile", DEFAULT_DEBUGLOGFILE));
+    if (logfile.is_absolute()) {
+        return logfile;
+    } else {
+        return GetDataDir() / logfile;
+    }
+}
+
+bool OpenDebugLog()
 {
     boost::call_once(&DebugPrintInit, debugPrintInitFlag);
     boost::mutex::scoped_lock scoped_lock(*mutexDebugLog);
 
     assert(fileout == nullptr);
     assert(vMsgsBeforeOpenLog);
-    fs::path pathDebug = GetDataDir() / "debug.log";
+    fs::path pathDebug = GetDebugLogPath();
+
     fileout = fsbridge::fopen(pathDebug, "a");
-    if (fileout) {
-        setbuf(fileout, nullptr); // unbuffered
-        // dump buffered messages from before we opened the log
-        while (!vMsgsBeforeOpenLog->empty()) {
-            FileWriteStr(vMsgsBeforeOpenLog->front(), fileout);
-            vMsgsBeforeOpenLog->pop_front();
-        }
+    if (!fileout) {
+        return false;
+    }
+
+    setbuf(fileout, nullptr); // unbuffered
+    // dump buffered messages from before we opened the log
+    while (!vMsgsBeforeOpenLog->empty()) {
+        FileWriteStr(vMsgsBeforeOpenLog->front(), fileout);
+        vMsgsBeforeOpenLog->pop_front();
     }
 
     delete vMsgsBeforeOpenLog;
     vMsgsBeforeOpenLog = nullptr;
+    return true;
 }
 
 struct CLogCategoryDesc
@@ -355,7 +365,7 @@ int LogPrintStr(const std::string &str)
             // reopen the log file, if requested
             if (fReopenDebugLog) {
                 fReopenDebugLog = false;
-                fs::path pathDebug = GetDataDir() / "debug.log";
+                fs::path pathDebug = GetDebugLogPath();
                 if (fsbridge::freopen(pathDebug,"a",fileout) != nullptr)
                     setbuf(fileout, nullptr); // unbuffered
             }
@@ -366,6 +376,50 @@ int LogPrintStr(const std::string &str)
     return ret;
 }
 
+/** A map that contains all the currently held directory locks. After
+ * successful locking, these will be held here until the global destructor
+ * cleans them up and thus automatically unlocks them, or ReleaseDirectoryLocks
+ * is called.
+ */
+static std::map<std::string, std::unique_ptr<boost::interprocess::file_lock>> dir_locks;
+/** Mutex to protect dir_locks. */
+static std::mutex cs_dir_locks;
+
+bool LockDirectory(const fs::path& directory, const std::string lockfile_name, bool probe_only)
+{
+    std::lock_guard<std::mutex> ulock(cs_dir_locks);
+    fs::path pathLockFile = directory / lockfile_name;
+
+    // If a lock for this directory already exists in the map, don't try to re-lock it
+    if (dir_locks.count(pathLockFile.string())) {
+        return true;
+    }
+
+    // Create empty lock file if it doesn't exist.
+    FILE* file = fsbridge::fopen(pathLockFile, "a");
+    if (file) fclose(file);
+
+    try {
+        auto lock = MakeUnique<boost::interprocess::file_lock>(pathLockFile.string().c_str());
+        if (!lock->try_lock()) {
+            return false;
+        }
+        if (!probe_only) {
+            // Lock successful and we're not just probing, put it into the map
+            dir_locks.emplace(pathLockFile.string(), std::move(lock));
+        }
+    } catch (const boost::interprocess::interprocess_exception& e) {
+        return error("Error while attempting to lock directory %s: %s", directory.string(), e.what());
+    }
+    return true;
+}
+
+void ReleaseDirectoryLocks()
+{
+    std::lock_guard<std::mutex> ulock(cs_dir_locks);
+    dir_locks.clear();
+}
+
 /** Interpret string as boolean, for argument parsing */
 static bool InterpretBool(const std::string& strValue)
 {
@@ -624,6 +678,9 @@ void ArgsManager::ReadConfigFile(const std::string& confPath)
     }
     // If datadir is changed in .conf file:
     ClearDatadirCache();
+    if (!fs::is_directory(GetDataDir(false))) {
+        throw std::runtime_error(strprintf("specified data directory \"%s\" does not exist.", gArgs.GetArg("-datadir", "").c_str()));
+    }
 }
 
 #ifndef WIN32
@@ -774,7 +831,7 @@ void ShrinkDebugFile()
     // Amount of debug.log to save at end when shrinking (must fit in memory)
     constexpr size_t RECENT_DEBUG_HISTORY_SIZE = 10 * 1000000;
     // Scroll debug.log if it's getting too big
-    fs::path pathLog = GetDataDir() / "debug.log";
+    fs::path pathLog = GetDebugLogPath();
     FILE* file = fsbridge::fopen(pathLog, "r");
     // If debug.log file is more than 10% bigger the RECENT_DEBUG_HISTORY_SIZE
     // trim it down by saving only the last RECENT_DEBUG_HISTORY_SIZE bytes