Add -debuglogfile option

This patch adds an option to configure the name and/or directory of the
debug log.

The user can specify either a relative path, in which case the path
is relative to the data directory. They can also specify an absolute
path to put the log anywhere else in the file system.

backports bitcoin/bitcoin@cf5f432

Author: random-zebra

src/init.cpp

@@ -383,6 +383,7 @@ std::string HelpMessage(HelpMessageMode mode)
 #endif
     }
     strUsage += HelpMessageOpt("-datadir=<dir>", _("Specify data directory"));
+    strUsage += HelpMessageOpt("-debuglogfile=<file>", strprintf(_("Specify location of debug log file: this can be an absolute path or a path relative to the data directory (default: %s)"), DEFAULT_DEBUGLOGFILE));
     strUsage += HelpMessageOpt("-dbcache=<n>", strprintf(_("Set database cache size in megabytes (%d to %d, default: %d)"), nMinDbCache, nMaxDbCache, nDefaultDbCache));
     strUsage += HelpMessageOpt("-loadblock=<file>", _("Imports blocks from external blk000??.dat file") + " " + _("on startup"));
     strUsage += HelpMessageOpt("-maxreorg=<n>", strprintf(_("Set the Maximum reorg depth (default: %u)"), DEFAULT_MAX_REORG_DEPTH));
@@ -1063,8 +1064,9 @@ bool AppInit2()
 #endif
     if (GetBoolArg("-shrinkdebugfile", logCategories != BCLog::NONE))
         ShrinkDebugFile();
-    if (fPrintToDebugLog)
-        OpenDebugLog();
+    if (fPrintToDebugLog && !OpenDebugLog()) {
+        return UIError(strprintf("Could not open debug log file %s", GetDebugLogPath().string()));
+    }
 #ifdef ENABLE_WALLET
     LogPrintf("Using BerkeleyDB version %s\n", DbEnv::version(0, 0, 0));
 #endif

src/util.cpp

@@ -102,6 +102,9 @@ bool fSucessfullyLoaded = false;
 std::vector<int64_t> obfuScationDenominations;
 std::string strBudgetMode = "";
 
+const char * const DEFAULT_DEBUGLOGFILE = "debug.log";
+namespace fs = boost::filesystem;
+
 std::map<std::string, std::string> mapArgs;
 std::map<std::string, std::vector<std::string> > mapMultiArgs;
 bool fPrintToConsole = false;
@@ -203,17 +206,29 @@ static void DebugPrintInit()
     vMsgsBeforeOpenLog = new std::list<std::string>;
 }
 
-void OpenDebugLog()
+fs::path GetDebugLogPath()
+{
+    fs::path logfile(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);
 
-    boost::filesystem::path pathDebug = GetDataDir() / "debug.log";
+    boost::filesystem::path pathDebug = GetDebugLogPath();
+
     fileout = fopen(pathDebug.string().c_str(), "a");
-    if (fileout) setbuf(fileout, nullptr); // unbuffered
+    if (!fileout) return false;
 
+    setbuf(fileout, nullptr); // unbuffered
     // dump buffered messages from before we opened the log
     while (!vMsgsBeforeOpenLog->empty()) {
         FileWriteStr(vMsgsBeforeOpenLog->front(), fileout);
@@ -222,6 +237,7 @@ void OpenDebugLog()
 
     delete vMsgsBeforeOpenLog;
     vMsgsBeforeOpenLog = nullptr;
+    return true;
 }
 
 struct CLogCategoryDesc
@@ -357,7 +373,7 @@ int LogPrintStr(const std::string& str)
             // reopen the log file, if requested
             if (fReopenDebugLog) {
                 fReopenDebugLog = false;
-                boost::filesystem::path pathDebug = GetDataDir() / "debug.log";
+                boost::filesystem::path pathDebug = GetDebugLogPath();
                 if (freopen(pathDebug.string().c_str(),"a",fileout) != NULL)
                     setbuf(fileout, NULL); // unbuffered
             }
@@ -497,7 +513,6 @@ void PrintExceptionContinue(const std::exception* pex, const char* pszThread)
 
 boost::filesystem::path GetDefaultDataDir()
 {
-    namespace fs = boost::filesystem;
 // Windows < Vista: C:\Documents and Settings\Username\Application Data\PIVX
 // Windows >= Vista: C:\Users\Username\AppData\Roaming\PIVX
 // Mac: ~/Library/Application Support/PIVX
@@ -524,14 +539,12 @@ boost::filesystem::path GetDefaultDataDir()
 #endif
 }
 
-static boost::filesystem::path pathCached;
-static boost::filesystem::path pathCachedNetSpecific;
+static fs::path pathCached;
+static fs::path pathCachedNetSpecific;
 static RecursiveMutex csPathCached;
 
-const boost::filesystem::path& GetDataDir(bool fNetSpecific)
+const fs::path& GetDataDir(bool fNetSpecific)
 {
-    namespace fs = boost::filesystem;
-
     LOCK(csPathCached);
 
     fs::path& path = fNetSpecific ? pathCachedNetSpecific : pathCached;
@@ -755,7 +768,7 @@ void AllocateFileRange(FILE* file, unsigned int offset, unsigned int length)
 void ShrinkDebugFile()
 {
     // Scroll debug.log if it's getting too big
-    boost::filesystem::path pathLog = GetDataDir() / "debug.log";
+    boost::filesystem::path pathLog = GetDebugLogPath();
     FILE* file = fopen(pathLog.string().c_str(), "r");
     if (file && boost::filesystem::file_size(pathLog) > 10 * 1000000) {
         // Restart the file with some of the end
@@ -776,8 +789,6 @@ void ShrinkDebugFile()
 #ifdef WIN32
 boost::filesystem::path GetSpecialFolderPath(int nFolder, bool fCreate)
 {
-    namespace fs = boost::filesystem;
-
     char pszPath[MAX_PATH] = "";
 
     if (SHGetSpecialFolderPathA(NULL, pszPath, nFolder, fCreate)) {

src/util.h

@@ -32,6 +32,8 @@
 #include <boost/thread/exceptions.hpp>
 #include <boost/thread/condition_variable.hpp> // for boost::thread_interrupted
 
+extern const char * const DEFAULT_DEBUGLOGFILE;
+
 //PIVX only features
 
 extern bool fMasterNode;
@@ -161,7 +163,8 @@ void ReadConfigFile(std::map<std::string, std::string>& mapSettingsRet, std::map
 boost::filesystem::path GetSpecialFolderPath(int nFolder, bool fCreate = true);
 #endif
 boost::filesystem::path GetTempPath();
-void OpenDebugLog();
+boost::filesystem::path GetDebugLogPath();
+bool OpenDebugLog();
 void ShrinkDebugFile();
 void runCommand(std::string strCommand);