From: Ondřej Surý <ondrej@isc.org>
Date: Sat, 8 Feb 2020 12:31:51 +0000 (-0800)
Subject: Add semantic patch to NULL the destroyed pointer early
X-Git-Tag: v9.16.0~12^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b97d003033bc4a1151b1f6da70823206f1bcc65a;p=thirdparty%2Fbind9.git

Add semantic patch to NULL the destroyed pointer early

Our destroy functions usually look like this:

    void
    foo_destroy(foo_t **foop) {
        foo_t foo = *foop;
        ...destroy the contents of foo...
        *foop = NULL;
    }

nulling the pointer should be done as soon as possible which is
not always the case.  This commit adds simple semantic patch that
changes the example function to:

    void
    foo_destroy(foo_t **foop) {
        foo_t foo = *foop;
        *foop = NULL;
        ...destroy the contents of foo...
    }
---

diff --git a/cocci/null-the-pointer-early.spatch b/cocci/null-the-pointer-early.spatch
new file mode 100644
index 00000000000..46fdffc1230
--- /dev/null
+++ b/cocci/null-the-pointer-early.spatch
@@ -0,0 +1,21 @@
+@@
+type T;
+T **PP;
+T *P;
+@@
+
+  P = *PP;
++ *PP = NULL;
+  ...
+- *PP = NULL;
+
+@@
+type T;
+identifier PP;
+identifier P;
+@@
+
+  T *P = *PP;
++ *PP = NULL;
+  ...
+- *PP = NULL;