Add fxstat check to glibc_syscall_wrappers test.

tests/glibc_syscall_wrappers/test_fstat.c

+/*
+ * Copyright 2010 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can
+ * be found in the LICENSE file.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <sys/stat.h>
+
+int main(int argc, char** argv) {
+  struct stat st;
+  FILE* file;
+  int fd;
+  if (2 != argc) {
+    printf("Usage: sel_ldr test_fstat.nexe test_stat_data\n");
+    return 1;
+  }
+  st.st_size = 0;
+  printf("st_dev offset %d, size %d\n",
+         offsetof(struct stat, st_dev),
+         sizeof(st.st_dev));
+  printf("st_ino offset %d, size %d\n",
+         offsetof(struct stat, st_ino),
+         sizeof(st.st_ino));
+  printf("st_mode offset %d, size %d\n",
+         offsetof(struct stat, st_mode),
+         sizeof(st.st_mode));
+  printf("st_nlink offset %d, size %d\n",
+         offsetof(struct stat, st_nlink),
+         sizeof(st.st_nlink));
+  printf("st_uid offset %d, size %d\n",
+         offsetof(struct stat, st_uid),
+         sizeof(st.st_uid));
+  printf("st_gid offset %d, size %d\n",
+         offsetof(struct stat, st_gid),
+         sizeof(st.st_gid));
+  printf("st_rdev offset %d, size %d\n",
+         offsetof(struct stat, st_rdev),
+         sizeof(st.st_rdev));
+  printf("st_size offset %d, size %d\n",
+         offsetof(struct stat, st_size),
+         sizeof(st.st_size));
+  printf("st_blksize offset %d, size %d\n",
+         offsetof(struct stat, st_blksize),
+         sizeof(st.st_blksize));
+  printf("st_blocks offset %d, size %d\n",
+         offsetof(struct stat, st_blocks),
+         sizeof(st.st_blocks));
+  printf("st_atim offset %d, size %d\n",
+         offsetof(struct stat, st_atim),
+         sizeof(st.st_atim));
+  printf("struct st size %d\n",
+         sizeof(st));
+  file = fopen(argv[1], "r");
+  if (file == NULL)
+    return 2;
+  fd = fileno(file);
+  errno = 0;
+  if (fstat(fd, &st))
+    return 3;
+  printf("%d\n", (int)st.st_size);
+  if (errno != 0)
+    return 4;
+  if (fclose(file))
+    return 5;
+  errno = 0;
+  if (fstat(-1, &st) != -1)
+    return 6;
+  if (errno != EBADF)
+    return 7;
+  return 0;
+}