From 323029baa6958781ffae5da331dfc918d66a7117 Mon Sep 17 00:00:00 2001
From: Wen Hui <wen.hui.ware@gmail.com>
Date: Thu, 24 Sep 2020 11:17:53 -0400
Subject: [PATCH] rdb.c: handle fclose error case differently to avoid double
 fclose (#7307)

When fclose would fail, the previous implementation would have attempted to do fclose again
this can in theory lead to segfault.

other changes:
check for non-zero return value as failure rather than a specific error code.
this doesn't fix a real bug, just a minor cleanup.
---
 src/rdb.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/rdb.c b/src/rdb.c
index 6420e9924..73bc143f5 100644
--- a/src/rdb.c
+++ b/src/rdb.c
@@ -1314,7 +1314,7 @@ werr: /* Write error. */
 int rdbSave(char *filename, rdbSaveInfo *rsi) {
     char tmpfile[256];
     char cwd[MAXPATHLEN]; /* Current working dir path for error messages. */
-    FILE *fp;
+    FILE *fp = NULL;
     rio rdb;
     int error = 0;
 
@@ -1343,10 +1343,11 @@ int rdbSave(char *filename, rdbSaveInfo *rsi) {
     }
 
     /* Make sure data will not remain on the OS's output buffers */
-    if (fflush(fp) == EOF) goto werr;
-    if (fsync(fileno(fp)) == -1) goto werr;
-    if (fclose(fp) == EOF) goto werr;
-
+    if (fflush(fp)) goto werr;
+    if (fsync(fileno(fp))) goto werr;
+    if (fclose(fp)) { fp = NULL; goto werr; }
+    fp = NULL;
+    
     /* Use RENAME to make sure the DB file is changed atomically only
      * if the generate DB file is ok. */
     if (rename(tmpfile,filename) == -1) {
@@ -1372,7 +1373,7 @@ int rdbSave(char *filename, rdbSaveInfo *rsi) {
 
 werr:
     serverLog(LL_WARNING,"Write error saving DB on disk: %s", strerror(errno));
-    fclose(fp);
+    if (fp) fclose(fp);
     unlink(tmpfile);
     stopSaving(0);
     return C_ERR;