Add umask unit test

Author: fluiddot

test/stat/test_umask.c

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2013 The Emscripten Authors.  All rights reserved.
+ * Emscripten is available under two separate licenses, the MIT license and the
+ * University of Illinois/NCSA Open Source License.  Both these licenses can be
+ * found in the LICENSE file.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+mode_t get_umask() {
+    mode_t current = umask(0);  // Set umask to 0 and get the old value
+    umask(current);  // Immediately set it back
+    return current;
+}
+
+void create_file(const char *path, const char *buffer) {
+  mode_t mode = 0777 - get_umask();
+  int fd = open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
+  assert(fd >= 0);
+
+  int err = write(fd, buffer, sizeof(char) * strlen(buffer));
+  assert(err ==  (sizeof(char) * strlen(buffer)));
+
+  close(fd);
+}
+
+void cleanup() {
+  unlink("umask_test_file");
+}
+
+void test() {
+  // Get the default umask
+  mode_t default_umask = get_umask();
+  printf("default umask: %o\n", default_umask);
+  assert(default_umask == 027);
+
+  // Create a new file with default umask
+  create_file("umask_test_file", "abcdef");
+  struct stat st;
+  stat("umask_test_file", &st);
+  printf("default_umask - stat: %o\n", st.st_mode);
+  assert((st.st_mode & 0666) == 0640);
+  unlink("umask_test_file");
+
+  // Set new umask
+  mode_t new_umask = 022;
+  mode_t old_umask = umask(new_umask);
+
+  // Create a new file with new umask
+  create_file("umask_test_file", "abcdef");
+  stat("umask_test_file", &st);
+  printf("new_umask - stat: %o\n", st.st_mode);
+  assert((st.st_mode & 0666) == 0644);
+
+  // Restore the old umask
+  umask(old_umask);
+  
+  puts("success");
+}
+
+int main() {
+  atexit(cleanup);
+  signal(SIGABRT, cleanup);
+  test();
+  return EXIT_SUCCESS;
+}

test/test_core.py

@@ -5609,6 +5609,10 @@ def test_statx(self):
     self.set_setting("FORCE_FILESYSTEM")
     self.do_runf('stat/test_statx.c', 'success')
 
+  def test_umask(self):
+    self.set_setting("FORCE_FILESYSTEM")
+    self.do_runf('stat/test_umask.c', 'success')
+
   def test_fstatat(self):
     self.do_runf('stat/test_fstatat.c', 'success')