use O_TMPFILE if it works/is supported in __archive_mktemp

This makes the function safer on linux since the file is warrantied to never
be visible on the filesystem, cannot be linked anywhere unless O_EXCL is
not specified and it is lost forever on any kind of program termination.

diff --git a/libarchive/archive_util.c b/libarchive/archive_util.c
index c76ecc5b05b1fca53402b3e22ee2d0e2c6830409..b1582edbe308ccc3a00d5af393583c505e8c2c14 100644 (file)
--- a/libarchive/archive_util.c
+++ b/libarchive/archive_util.c
@@ -433,6 +433,11 @@ __archive_mktemp(const char *tmpdir)
                if (temp_name.s[temp_name.length-1] != '/')
                        archive_strappend_char(&temp_name, '/');
        }
+#ifdef O_TMPFILE
+       fd = open(temp_name.s, O_RDWR|O_CLOEXEC|O_TMPFILE|O_EXCL, 0600); 
+       if(fd >= 0)
+               goto exit_tmpfile;
+#endif
        archive_strcat(&temp_name, "libarchive_XXXXXX");
        fd = mkstemp(temp_name.s);
        if (fd < 0)