[compiler-rt] openat2 syscall interception. (llvm#153846)

Author: devnexen

compiler-rt/lib/sanitizer_common/sanitizer_common_syscalls.inc

@@ -143,6 +143,12 @@ struct sanitizer_kernel_sockaddr {
   char sa_data[14];
 };
 
+struct sanitizer_kernel_open_how {
+  u64 flags;
+  u64 mode;
+  u64 resolve;
+};
+
 // Real sigset size is always passed as a syscall argument.
 // Declare it "void" to catch sizeof(kernel_sigset_t).
 typedef void kernel_sigset_t;
@@ -2843,6 +2849,18 @@ PRE_SYSCALL(openat)(long dfd, const void *filename, long flags, long mode) {
 POST_SYSCALL(openat)
 (long res, long dfd, const void *filename, long flags, long mode) {}
 
+PRE_SYSCALL(openat2)(long dfd, const void* filename,
+                     const sanitizer_kernel_open_how* how, uptr howlen) {
+  if (filename)
+    PRE_READ(filename, __sanitizer::internal_strlen((const char*)filename) + 1);
+
+  if (how)
+    PRE_READ(how, howlen);
+}
+
+POST_SYSCALL(openat2)(long res, long dfd, const void* filename,
+                      const sanitizer_kernel_open_how* how, uptr howlen) {}
+
 PRE_SYSCALL(newfstatat)
 (long dfd, const void *filename, void *statbuf, long flag) {
   if (filename)