Add user-defined callback on write() calls.

Add dfsan_set_write_callback(), which sets a callback to be invoked when
a write() call is invoked within DFSan instrumented code.

Patch by Sam Kerner!

Differential Revision: http://reviews.llvm.org/D3268

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@207131 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 0 deletions

diff --git a/include/sanitizer/dfsan_interface.h b/include/sanitizer/dfsan_interface.h
index 913e7f3d0..bcd4ae002 100644
--- a/include/sanitizer/dfsan_interface.h
+++ b/include/sanitizer/dfsan_interface.h
@@ -39,6 +39,9 @@ struct dfsan_label_info {
   void *userdata;
 };
 
+/// Signature of the callback argument to dfsan_set_write_callback().
+typedef void (*dfsan_write_callback_t)(int fd, const void *buf, size_t count);
+
 /// Computes the union of \c l1 and \c l2, possibly creating a union label in
 /// the process.
 dfsan_label dfsan_union(dfsan_label l1, dfsan_label l2);
@@ -77,6 +80,11 @@ dfsan_label dfsan_has_label_with_desc(dfsan_label label, const char *desc);
 /// Returns the number of labels allocated.
 size_t dfsan_get_label_count(void);
 
+/// Sets a callback to be invoked on calls to write().  The callback is invoked
+/// before the write is done.  The write is not guaranteed to succeed when the
+/// callback executes.  Pass in NULL to remove any callback.
+void dfsan_set_write_callback(dfsan_write_callback_t labeled_write_callback);
+
 #ifdef __cplusplus
 }  // extern "C"