--- os/log.c.old	2010-01-23 02:08:06.000000000 +0100
+++ os/log.c	2010-01-23 05:09:15.000000000 +0100
@@ -108,6 +108,8 @@
 #endif
 
 static FILE *logFile = NULL;
+static Bool logTimestamp = TRUE;
+static Bool logFileTimestamp = TRUE;
 static Bool logFlush = FALSE;
 static Bool logSync = FALSE;
 static int logVerbosity = DEFAULT_LOG_VERBOSITY;
@@ -251,13 +253,76 @@
     }
 }
 
+static void
+_LogWriteFile(FILE *file, Bool *writePrefix, char *prefix, size_t prefixLen, char *message, size_t len)
+{
+    const char *ptr, *pos;
+    size_t sublen;
+
+    ptr = message;
+    do {
+	pos = strchr(ptr, '\n');
+	if (pos != NULL)
+	    sublen = pos-ptr+1;
+	else
+	    sublen = len;
+	if (*writePrefix && prefixLen)
+	    fwrite(prefix, prefixLen, 1, file);
+	*writePrefix = (pos != NULL);
+	fwrite(ptr, sublen, 1, file);
+	ptr += sublen;
+	len -= sublen;
+    } while (len);
+}
+
+static size_t
+_LogWriteBuffer(Bool *writePrefix, char *prefix, size_t prefixLen, char *message, size_t len, Bool write)
+{
+    const char *ptr, *pos;
+    size_t sublen;
+    size_t total;
+
+    total = 0;
+    ptr = message;
+    do {
+	pos = strchr(ptr, '\n');
+	if (pos != NULL)
+	    sublen = pos-ptr+1;
+	else
+	    sublen = len;
+	if (*writePrefix && prefixLen) {
+	    total += prefixLen;
+	    if (write) {
+		bufferUnused -= prefixLen;
+		memcpy(saveBuffer + bufferPos, prefix, prefixLen);
+		bufferPos += prefixLen;
+	    }
+	}
+	*writePrefix = (pos != NULL);
+	total += sublen;
+	if (write) {
+	    bufferUnused -= sublen;
+	    memcpy(saveBuffer + bufferPos, ptr, sublen);
+	    bufferPos += sublen;
+	}
+	ptr += sublen;
+	len -= sublen;
+    } while (len);
+    return total;
+}
+
 /* This function does the actual log message writes. */
 
 void
 LogVWrite(int verb, const char *f, va_list args)
 {
     static char tmpBuffer[1024];
+    static char timestamp[21];
+    const char *pos;
     int len = 0;
+    size_t timestampLen = 0;
+    time_t t;
+    struct tm *tm;
 
     /*
      * Since a va_list can only be processed once, write the string to a
@@ -267,12 +332,29 @@
     if (verb < 0 || logFileVerbosity >= verb || logVerbosity >= verb) {
 	vsnprintf(tmpBuffer, sizeof(tmpBuffer), f, args);
 	len = strlen(tmpBuffer);
+	if (len == 0)
+	    return;
+    } else {
+	return;
+    }
+    pos = strchr(tmpBuffer, '\n');
+    if (logTimestamp || logFileTimestamp || (pos != NULL && *(pos+1) != '\0')) {
+	t = time(NULL);
+	if (t != (time_t)-1)
+	    tm = localtime(&t);
+	else
+	    tm = NULL;
+	if (tm != NULL)
+	    timestampLen = strftime(timestamp, sizeof(timestamp), "%F %T ", tm);
+    }
+    if ((verb < 0 || logVerbosity >= verb)) {
+	_LogWriteFile(stderr, &logTimestamp,
+	    timestamp, timestampLen, tmpBuffer, len);
     }
-    if ((verb < 0 || logVerbosity >= verb) && len > 0)
-	fwrite(tmpBuffer, len, 1, stderr);
-    if ((verb < 0 || logFileVerbosity >= verb) && len > 0) {
+    if ((verb < 0 || logFileVerbosity >= verb)) {
 	if (logFile) {
-	    fwrite(tmpBuffer, len, 1, logFile);
+	    _LogWriteFile(logFile, &logFileTimestamp,
+		timestamp, timestampLen, tmpBuffer, len);
 	    if (logFlush) {
 		fflush(logFile);
 #ifndef WIN32
@@ -286,8 +368,13 @@
 	     * xalloc() and friends can't be used.
 	     */
 	    if (len > bufferUnused) {
-		bufferSize += 1024;
-		bufferUnused += 1024;
+		Bool tmpLog = logFileTimestamp;
+		size_t more = _LogWriteBuffer(&tmpLog,
+		    timestamp, timestampLen, tmpBuffer, len, FALSE);
+		if (more < 1024)
+		    more = 1024;
+		bufferSize += more;
+		bufferUnused += more;
 		if (saveBuffer)
 		    saveBuffer = realloc(saveBuffer, bufferSize);
 		else
@@ -295,9 +382,8 @@
 		if (!saveBuffer)
 		    FatalError("realloc() failed while saving log messages\n");
 	    }
-	    bufferUnused -= len;
-	    memcpy(saveBuffer + bufferPos, tmpBuffer, len);
-	    bufferPos += len;
+	    _LogWriteBuffer(&logFileTimestamp,
+		timestamp, timestampLen, tmpBuffer, len, TRUE);
 	}
     }
 }