Merge pull request iovisor#1005 from pchaigno/rewrite-only-deref

Restrict rewrite of unary operators to dereference operator
ego · Mar 7, 2017 · 575b3e5 · 575b3e5
2 parents d05e66d + 4c6ecb4
commit 575b3e5
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Showing 2 changed files with 12 additions and 1 deletion.
diff --git a/src/cc/frontends/clang/b_frontend_action.cc b/src/cc/frontends/clang/b_frontend_action.cc
@@ -200,7 +200,7 @@ bool ProbeVisitor::VisitBinaryOperator(BinaryOperator *E) {
  return true;
 }
 bool ProbeVisitor::VisitUnaryOperator(UnaryOperator *E) {
- if (E->getOpcode() == UO_AddrOf)
+ if (E->getOpcode() != UO_Deref)
  return true;
  if (memb_visited_.find(E) != memb_visited_.end())
  return true;

diff --git a/tests/python/test_clang.py b/tests/python/test_clang.py
@@ -408,6 +408,17 @@ def test_bpf_dins_pkt_rewrite(self):
  """
  b = BPF(text=text)
 
+ def test_unary_operator(self):
+ text = """
+#include <linux/fs.h>
+#include <uapi/linux/ptrace.h>
+int trace_read_entry(struct pt_regs *ctx, struct file *file) {
+ return !file->f_op->read_iter;
+}
+ """
+ b = BPF(text=text)
+ b.attach_kprobe(event="__vfs_read", fn_name="trace_read_entry")
+
 if __name__ == "__main__":
  main()