add tests

Author: devnexen

compiler-rt/test/sanitizer_common/TestCases/Linux/preadv2.cpp

@@ -0,0 +1,28 @@
+// RUN: %clangxx -O0 %s -o %t
+
+// UNSUPPORTED: android
+
+#include <assert.h>
+#include <fcntl.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+int main(void) {
+  int fd = open("/proc/self/stat", O_RDONLY);
+  char bufa[7];
+  char bufb[7];
+  struct iovec vec[2];
+  vec[0].iov_base = bufa + 4;
+  vec[0].iov_len = 1;
+  vec[1].iov_base = bufb;
+  vec[1].iov_len = sizeof(bufb);
+  ssize_t rd = preadv2(fd, vec, 2, 0, 0);
+  assert(rd > 0);
+  vec[0].iov_base = bufa;
+  rd = preadv2(fd, vec, 2, 0, 0);
+  assert(rd > 0);
+  rd = preadv2(fd, vec, 5, -25, 0);
+  assert(rd < 0);
+  close(fd);
+  return 0;
+}