From 83c0dea2e40eec14e770083fc764cf5250c5c439 Mon Sep 17 00:00:00 2001
From: "Jerry (Xinyu Hou)" <xinyu@synergy-project.org>
Date: Thu, 14 Jul 2016 07:55:13 -0700
Subject: [PATCH] #4792 Calculated log message size rather than using fixed
 size

---
 src/lib/base/Log.cpp             | 25 ++++++++++++++++++-------
 src/lib/base/Log.h               |  2 --
 src/lib/synergy/ProtocolUtil.cpp |  6 +-----
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/src/lib/base/Log.cpp b/src/lib/base/Log.cpp
index 7ad8ae1b..42389bda 100644
--- a/src/lib/base/Log.cpp
+++ b/src/lib/base/Log.cpp
@@ -172,22 +172,33 @@ Log::print(const char* file, int line, const char* fmt, ...)
 	// do not prefix time and file for kPRINT (CLOG_PRINT)
 	if (priority != kPRINT) {
 
-		char message[kLogMessageLength];
-
 		struct tm *tm;
-		char tmp[220];
+		char timestamp[50];
 		time_t t;
 		time(&t);
 		tm = localtime(&t);
-		sprintf(tmp, "%04i-%02i-%02iT%02i:%02i:%02i", tm->tm_year + 1900, tm->tm_mon+1, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
+		sprintf(timestamp, "%04i-%02i-%02iT%02i:%02i:%02i", tm->tm_year + 1900, tm->tm_mon+1, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
 
-#ifndef NDEBUG	
-		sprintf(message, "[%s] %s: %s\n\t%s,%d", tmp, g_priority[priority], buffer, file, line);
+		// square brackets, spaces, comma and null terminator take about 10
+		int size = 10;
+		size += strlen(timestamp);
+		size += strlen(g_priority[priority]);
+		size += strlen(buffer);
+#ifndef NDEBUG
+		size += strlen(file);
+		// assume there is no file contains over 100k lines of code
+		size += 6;
+#endif
+		char* message = new char[size];
+
+#ifndef NDEBUG
+		sprintf(message, "[%s] %s: %s\n\t%s,%d", timestamp, g_priority[priority], buffer, file, line);
 #else
-		sprintf(message, "[%s] %s: %s", tmp, g_priority[priority], buffer);
+		sprintf(message, "[%s] %s: %s", timestamp, g_priority[priority], buffer);
 #endif
 
 		output(priority, message);
+		delete[] message;
 	} else {
 		output(priority, buffer);
 	}
diff --git a/src/lib/base/Log.h b/src/lib/base/Log.h
index eaa2c8a8..ab36ce6a 100644
--- a/src/lib/base/Log.h
+++ b/src/lib/base/Log.h
@@ -139,8 +139,6 @@ private:
 	int					m_maxPriority;
 };
 
-const UInt16 kLogMessageLength = 2048;
-
 /*!
 \def LOG(arg)
 Write to the log.  Because macros cannot accept variable arguments, this
diff --git a/src/lib/synergy/ProtocolUtil.cpp b/src/lib/synergy/ProtocolUtil.cpp
index ee73bebf..d5e0aed7 100644
--- a/src/lib/synergy/ProtocolUtil.cpp
+++ b/src/lib/synergy/ProtocolUtil.cpp
@@ -230,11 +230,7 @@ ProtocolUtil::vreadf(synergy::IStream* stream, const char* fmt, va_list args)
 					throw;
 				}
 
-				// don't cause buffer overrun, using +100 chars in case
-				// someone modifies this log message in future.
-				if (len + 100 < kLogMessageLength) {
-					LOG((CLOG_DEBUG2 "readf: read %d byte string: %.*s", len, len, sBuffer));
-				}
+				LOG((CLOG_DEBUG2 "readf: read %d byte string: %.*s", len, len, sBuffer));
 
 				// save the data
 				String* dst = va_arg(args, String*);