* util.c (valid_filename): use O_EXCL to get rid of clobbering

  existing files in race conditions.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@15586 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 5 insertions, 9 deletions

diff --git a/util.c b/util.c
index 8a00aedf60..136ff1b213 100644
--- a/util.c
+++ b/util.c
@@ -346,22 +346,18 @@ valid_filename(const char *s)
     int fd;
 
     /*
-    // if the file exists, then it's a valid filename!
-    */
-
-    if (_access(s, 0) == 0) {
-	return 1;
-    }
-
-    /*
     // It doesn't exist, so see if we can open it.
     */
 
-    if ((fd = _open(s, O_CREAT, 0666)) >= 0) {
+    if ((fd = _open(s, O_CREAT|O_EXCL, 0666)) >= 0) {
 	_close(fd);
 	_unlink(s);	/* don't leave it laying around */
 	return 1;
     }
+    else if (errno == EEXIST) {
+	/* if the file exists, then it's a valid filename! */
+	return 1;
+    }
     return 0;
 }
 #endif