Ensure the ino we give to readdir matches the ino we give to stat

src/library_syscall.js

@@ -697,23 +697,22 @@ var SyscallsLibrary = {
 
     var startIdx = Math.floor(off / struct_size);
     var endIdx = Math.min(stream.getdents.length, startIdx + Math.floor(count/struct_size))
+    var node;
     for (var idx = startIdx; idx < endIdx; idx++) {
-      var id;
       var type;
       var name = stream.getdents[idx];
       if (name === '.') {
-        id = stream.node.id;
+        node = stream.node;
         type = 4; // DT_DIR
       }
       else if (name === '..') {
         var lookup = FS.lookupPath(stream.path, { parent: true });
-        id = lookup.node.id;
+        node = lookup.node;
         type = 4; // DT_DIR
       }
       else {
-        var child;
         try {
-          child = FS.lookupNode(stream.node, name);
+          node = FS.lookupNode(stream.node, name);
         } catch (e) {
           // If the entry is not a directory, file, or symlink, nodefs
           // lookupNode will raise EINVAL. Skip these and continue.
@@ -722,16 +721,17 @@ var SyscallsLibrary = {
           }
           throw e;
         }
-        id = child.id;
-        type = FS.isChrdev(child.mode) ? 2 :  // DT_CHR, character device.
-               FS.isDir(child.mode) ? 4 :     // DT_DIR, directory.
-               FS.isLink(child.mode) ? 10 :   // DT_LNK, symbolic link.
+        type = FS.isChrdev(node.mode) ? 2 :  // DT_CHR, character device.
+               FS.isDir(node.mode) ? 4 :     // DT_DIR, directory.
+               FS.isLink(node.mode) ? 10 :   // DT_LNK, symbolic link.
                8;                             // DT_REG, regular file.
       }
-#if ASSERTIONS
-      assert(id);
-#endif
-      {{{ makeSetValue('dirp + pos', C_STRUCTS.dirent.d_ino, 'id', 'i64') }}};
+      // We use getattr to decide which ino we return to stat, so make sure to
+      // use it to decide which ino we return to readdir too. noderawfs puts the
+      // native inode into node.id and doesn't define node_ops.getattr so use
+      // that as a fallback.
+      var ino = node.node_ops.getattr?.(node).ino ?? node.id;
+      {{{ makeSetValue('dirp + pos', C_STRUCTS.dirent.d_ino, 'ino', 'i64') }}};
       {{{ makeSetValue('dirp + pos', C_STRUCTS.dirent.d_off, '(idx + 1) * struct_size', 'i64') }}};
       {{{ makeSetValue('dirp + pos', C_STRUCTS.dirent.d_reclen, C_STRUCTS.dirent.__size__, 'i16') }}};
       {{{ makeSetValue('dirp + pos', C_STRUCTS.dirent.d_type, 'type', 'i8') }}};

test/fs/test_fs_readdir_ino_matches_stat_ino.c

@@ -0,0 +1,68 @@
+#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>
+
+
+#if defined(__EMSCRIPTEN__)
+#include <emscripten.h>
+#endif
+
+void makedir(const char *dir) {
+  int rtn = mkdir(dir, 0777);
+  assert(rtn == 0);
+}
+
+void changedir(const char *dir) {
+  int rtn = chdir(dir);
+  assert(rtn == 0);
+}
+
+void setup() {
+#if defined(__EMSCRIPTEN__) && defined(NODEFS)
+  makedir("working");
+  emscripten_debugger();
+  EM_ASM(FS.mount(NODEFS, { root: '.' }, 'working'));
+  changedir("working");
+#endif
+}
+
+int main() {
+    setup();
+    int res = open("b", O_CREAT, 0777);
+    assert(res >= 0);
+    assert(close(res) == 0);
+    assert(symlink("b", "a") == 0);
+    int dirfd = open(".", O_RDONLY);
+    assert(dirfd > 0);
+    DIR *dirp;
+    dirp = fdopendir(dirfd);
+    assert(dirp != NULL);
+    struct dirent *ep;
+    int a_ino = -1;
+    int b_ino = -1;
+    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(a_ino >= 0);
+    assert(b_ino >= 0);
+    struct stat sta, stb;
+    assert(lstat("a", &sta) == 0);
+    assert(lstat("b", &stb) == 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");
+}

test/test_core.py

@@ -5900,6 +5900,17 @@ def test_fs_rename_on_existing(self, args):
       self.set_setting('FORCE_FILESYSTEM')
     self.do_runf('fs/test_fs_rename_on_existing.c', 'success', emcc_args=args)
 
+  @parameterized({
+    '': ([],),
+    'nodefs': (['-DNODEFS', '-lnodefs.js'],),
+    'noderawfs': (['-sNODERAWFS'],)
+  })
+  def test_fs_readdir_ino_matches_stat_ino(self, args):
+    if self.get_setting('WASMFS'):
+      self.set_setting('FORCE_FILESYSTEM')
+    self.do_runf('fs/test_fs_readdir_ino_matches_stat_ino.c', 'success', emcc_args=args)
+
+
   def test_sigalrm(self):
     self.do_runf('test_sigalrm.c', 'Received alarm!')
     self.set_setting('EXIT_RUNTIME')