Fix a crash that could occur in cdr_csv when mutliple threads tried to close the same file.

Do we actually need the locking here?  What happens if you open the same file twice, and
 two threads try to write to it at the same time?  Is fputs() going to write out the entire
 line at once?  I suspect that it could be possible for the second fopen to run during the
 first fputs, so the position could be in the middle of the previously written line...

Issue 10347, initial patch by explidous (but I removed all of the paranoia stuff..)


git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.4@82344 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 18 insertions, 10 deletions

diff --git a/cdr/cdr_csv.c b/cdr/cdr_csv.c
index 5475398ac..00b8de320 100644
--- a/cdr/cdr_csv.c
+++ b/cdr/cdr_csv.c
@@ -47,6 +47,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/module.h"
 #include "asterisk/logger.h"
 #include "asterisk/utils.h"
+#include "asterisk/lock.h"
 
 #define CSV_LOG_DIR "/cdr-csv"
 #define CSV_MASTER  "/Master.csv"
@@ -91,8 +92,8 @@ static char *config = "cdr.conf";
 
 static char *name = "csv";
 
-static FILE *mf = NULL;
-
+AST_MUTEX_DEFINE_STATIC(mf_lock);
+AST_MUTEX_DEFINE_STATIC(acf_lock);
 
 static int load_config(void)
 {
@@ -266,18 +267,26 @@ static int writefile(char *s, char *acc)
 		return -1;
 	}
 	snprintf(tmp, sizeof(tmp), "%s/%s/%s.csv", (char *)ast_config_AST_LOG_DIR,CSV_LOG_DIR, acc);
+
+	ast_mutex_lock(&acf_lock);
 	f = fopen(tmp, "a");
-	if (!f)
+	if (!f) {
+		ast_mutex_unlock(&acf_lock);
+		ast_log(LOG_ERROR, "Unable to open file %s : %s\n", tmp, strerror(errno));
 		return -1;
+	}
 	fputs(s, f);
 	fflush(f);
 	fclose(f);
+	ast_mutex_unlock(&acf_lock);
+
 	return 0;
 }
 
 
 static int csv_log(struct ast_cdr *cdr)
 {
+	FILE *mf = NULL;
 	/* Make sure we have a big enough buf */
 	char buf[1024];
 	char csvmaster[PATH_MAX];
@@ -291,16 +300,19 @@ static int csv_log(struct ast_cdr *cdr)
 		/* 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 */
+		ast_mutex_lock(&mf_lock);
 		mf = fopen(csvmaster, "a");
-		if (!mf) {
-			ast_log(LOG_ERROR, "Unable to re-open master file %s : %s\n", csvmaster, strerror(errno));
-		}
 		if (mf) {
 			fputs(buf, mf);
 			fflush(mf); /* be particularly anal here */
 			fclose(mf);
 			mf = NULL;
+			ast_mutex_unlock(&mf_lock);
+		} else {
+			ast_mutex_unlock(&mf_lock);
+			ast_log(LOG_ERROR, "Unable to re-open master file %s : %s\n", csvmaster, strerror(errno));
 		}
+
 		if (!ast_strlen_zero(cdr->accountcode)) {
 			if (writefile(buf, cdr->accountcode))
 				ast_log(LOG_WARNING, "Unable to write CSV record to account file '%s' : %s\n", cdr->accountcode, strerror(errno));
@@ -311,8 +323,6 @@ static int csv_log(struct ast_cdr *cdr)
 
 static int unload_module(void)
 {
-	if (mf)
-		fclose(mf);
 	ast_cdr_unregister(name);
 	return 0;
 }
@@ -327,8 +337,6 @@ static int load_module(void)
 	res = ast_cdr_register(name, ast_module_info->description, csv_log);
 	if (res) {
 		ast_log(LOG_ERROR, "Unable to register CSV CDR handling\n");
-		if (mf)
-			fclose(mf);
 	}
 	return res;
 }