--- cdr_csv.c.orig	2007-07-31 17:13:45.000000000 -0400
+++ cdr_csv.c	2007-07-31 15:56:03.000000000 -0400
@@ -48,6 +48,7 @@
 #include "asterisk/options.h"
 #include "asterisk/logger.h"
 #include "asterisk/utils.h"
+#include "asterisk/lock.h"
 
 #define CSV_LOG_DIR "/cdr-csv"
 #define CSV_MASTER  "/Master.csv"
@@ -94,6 +95,7 @@
 
 static FILE *mf = NULL;
 
+static ast_mutex_t filelock; /* lock to keep records from getting garbled */
 
 static int load_config(void)
 {
@@ -286,15 +288,11 @@
 		/* because of the absolutely unconditional need for the
 		   highest reliability possible in writing billing records,
 		   we open write and close the log file each time */
-		mf = fopen(csvmaster, "a");
-		if (!mf) {
-			ast_log(LOG_ERROR, "Unable to re-open master file %s : %s\n", csvmaster, strerror(errno));
-		}
 		if (mf) {
+			ast_mutex_lock(&filelock);
 			fputs(buf, mf);
+			ast_mutex_unlock(&filelock);
 			fflush(mf); /* be particularly anal here */
-			fclose(mf);
-			mf = NULL;
 		}
 		if (!ast_strlen_zero(cdr->accountcode)) {
 			if (writefile(buf, cdr->accountcode))
@@ -316,8 +314,21 @@
 {
 	int res;
 	
+	ast_mutex_init(&filelock);
+
 	if(!load_config())
 		return AST_MODULE_LOAD_DECLINE;
+	
+	char csvmaster[PATH_MAX];
+	snprintf(csvmaster, sizeof(csvmaster),"%s/%s/%s", ast_config_AST_LOG_DIR, CSV_LOG_DIR, CSV_MASTER);
+
+	mf = fopen(csvmaster, "a");
+
+	if (!mf) {
+		/* unable to open the file */
+		ast_log(LOG_ERROR, "Unable to open master file %s : %s\n", csvmaster, strerror(errno));
+		return AST_MODULE_LOAD_DECLINE;
+	}
 
 	res = ast_cdr_register(name, ast_module_info->description, csv_log);
 	if (res) {
@@ -332,6 +343,23 @@
 {
 	load_config();
 
+	char csvmaster[PATH_MAX];
+	snprintf(csvmaster, sizeof(csvmaster),"%s/%s/%s", ast_config_AST_LOG_DIR, CSV_LOG_DIR, CSV_MASTER);
+
+	if(mf) { /* close the file if it is open */
+		fclose(mf);
+		mf = NULL;
+	}
+	if(!mf) { /* reopen the file if it is closed */
+		mf = fopen(csvmaster, "a");
+
+		if (!mf) {
+			/* unable to open the file */
+			ast_log(LOG_ERROR, "Unable to re-open master file %s : %s\n", csvmaster, strerror(errno));
+			return AST_MODULE_LOAD_DECLINE;
+		}
+	}
+
 	return 0;
 }