Ensure the ino we give to readdir matches the ino we give to stat (#23139)

If we stat a file in the nodefs it gives a different value for the inode
than if we use readdir. Readdir gives the inode in the host file system,
stat gives the inode in the native file system. Ideally they should
agree about what the inode is.

Author: hoodmane

src/library_nodefs.js

@@ -138,7 +138,7 @@ addToLibrary({
         }
         return {
           dev: stat.dev,
-          ino: stat.ino,
+          ino: node.id,
           mode: stat.mode,
           nlink: stat.nlink,
           uid: stat.uid,

test/common.py

@@ -742,27 +742,16 @@ def make_executable(name):
 
 
 def make_dir_writeable(dirname):
-  # Ensure all files are readable and writable by the current user.
-  permission_bits = stat.S_IWRITE | stat.S_IREAD
-
-  def is_writable(path):
-    return (os.stat(path).st_mode & permission_bits) != permission_bits
-
-  def make_writable(path):
-    new_mode = os.stat(path).st_mode | permission_bits
-    os.chmod(path, new_mode)
-
   # Some tests make files and subdirectories read-only, so rmtree/unlink will not delete
   # them. Force-make everything writable in the subdirectory to make it
   # removable and re-attempt.
-  if not is_writable(dirname):
-    make_writable(dirname)
+  os.chmod(dirname, 0o777)
 
   for directory, subdirs, files in os.walk(dirname):
     for item in files + subdirs:
       i = os.path.join(directory, item)
       if not os.path.islink(i):
-        make_writable(i)
+        os.chmod(i, 0o777)
 
 
 def force_delete_dir(dirname):

test/fs/test_fs_readdir_ino_matches_stat_ino.c

@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+#include <dirent.h>
+
+// TODO: Consider merging this with test/dirent/test_readdir.c?
+// That test doesn't work on nodefs, which has to be fixed before these two
+// tests can be merged .
+
+void setup() {
+  // If the node working directory does not have execute permissions, then
+  // `fs.readdir` will fail. For that reason we have to work in a subdirectory
+  // and remove execute permissions from that.
+  mkdir("sub", 0775);
+  assert(chdir("sub") == 0);
+  int res = open("b", O_CREAT, 0777);
+  assert(res >= 0);
+  assert(close(res) == 0);
+  assert(symlink("b", "a") == 0);
+}
+
+int main() {
+  setup();
+  int dirfd = open(".", O_RDONLY);
+  assert(dirfd > 0);
+  DIR *dirp = fdopendir(dirfd);
+  assert(dirp != NULL);
+  struct stat sta, stb;
+  assert(lstat("a", &sta) == 0);
+  assert(lstat("b", &stb) == 0);
+  // Test that removing permissions from the directory does not affect the
+  // already open directory handle that we have (dirp).
+#ifndef NODERAWFS
+  assert(chmod(".", 0675) == 0);
+#endif
+  int a_ino = -1;
+  int b_ino = -1;
+  struct dirent *ep;
+  while ((ep = readdir(dirp))) {
+    if (strcmp(ep->d_name, "a") == 0) {
+      a_ino = ep->d_ino;
+    }
+    if (strcmp(ep->d_name, "b") == 0) {
+      b_ino = ep->d_ino;
+    }
+  }
+  assert(errno == 0);
+  assert(a_ino >= 0);
+  assert(b_ino >= 0);
+  printf("readdir a_ino: %d, b_ino: %d\n", a_ino, b_ino);
+  printf("stat    a_ino: %llu, b_ino: %llu\n", sta.st_ino, stb.st_ino);
+  assert(a_ino == sta.st_ino);
+  assert(b_ino == stb.st_ino);
+  printf("success\n");
+  return 0;
+}

test/test_core.py

@@ -5859,6 +5859,10 @@ def test_fs_rename_on_existing(self):
       self.set_setting('FORCE_FILESYSTEM')
     self.do_runf('fs/test_fs_rename_on_existing.c', 'success')
 
+  @also_with_nodefs_both
+  def test_fs_readdir_ino_matches_stat_ino(self):
+    self.do_runf('fs/test_fs_readdir_ino_matches_stat_ino.c', 'success')
+
   @also_with_nodefs_both
   def test_fs_open_no_permissions(self):
     self.do_runf('fs/test_fs_open_no_permissions.c', 'success')