Fix ABI wrapping for readdir()

Add missing ABI wrappers for readdir_r. The dirent struct size
is different on 64/32bit platforms.

b/302730696

starboard/shared/modular/BUILD.gn

@@ -18,6 +18,8 @@ if ((sb_is_modular || sb_is_evergreen_compatible) &&
     current_toolchain == starboard_toolchain) {
   source_set("starboard_layer_posix_abi_wrappers") {
     sources = [
+      "starboard_layer_posix_directory_abi_wrappers.cc",
+      "starboard_layer_posix_directory_abi_wrappers.h",
       "starboard_layer_posix_mmap_abi_wrappers.cc",
       "starboard_layer_posix_mmap_abi_wrappers.h",
       "starboard_layer_posix_pthread_abi_wrappers.cc",
@@ -42,6 +44,7 @@ if (sb_is_modular && !sb_is_evergreen &&
     current_toolchain == cobalt_toolchain) {
   source_set("cobalt_layer_posix_abi_wrappers") {
     sources = [
+      "cobalt_layer_posix_directory_abi_wrappers.cc",
       "cobalt_layer_posix_mmap_abi_wrappers.cc",
       "cobalt_layer_posix_pthread_abi_wrappers.cc",
       "cobalt_layer_posix_socket_abi_wrappers.cc",

starboard/shared/modular/cobalt_layer_posix_directory_abi_wrappers.cc

@@ -0,0 +1,30 @@
+// Copyright 2024 The Cobalt Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#if SB_API_VERSION >= 16
+
+#include <dirent.h>
+
+extern "C" {
+
+int __abi_wrap_readdir_r(DIR* dirp,
+                         struct dirent* entry,
+                         struct dirent** result);
+
+int readdir_r(DIR* dirp, struct dirent* entry, struct dirent** result) {
+  return __abi_wrap_readdir_r(dirp, entry, result);
+}
+}
+
+#endif  // SB_API_VERSION >= 16

starboard/shared/modular/starboard_layer_posix_directory_abi_wrappers.cc

@@ -0,0 +1,49 @@
+// Copyright 2024 The Cobalt Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "starboard/shared/modular/starboard_layer_posix_directory_abi_wrappers.h"
+#include <string.h>
+#include <algorithm>
+#include "starboard/common/log.h"
+
+int __abi_wrap_readdir_r(DIR* dirp,
+                         struct musl_dirent* musl_entry,
+                         struct musl_dirent** musl_result) {
+  // readdir_r segfaults if any of those parameters are missing.
+  SB_CHECK(dirp);
+  SB_CHECK(musl_entry);
+  SB_CHECK(musl_result);
+
+  struct dirent entry;  // The type from platform toolchain.
+  struct dirent* result;
+  int retval = readdir_r(dirp, &entry, &result);
+  if (retval != 0) {
+    return retval;
+  }
+  musl_entry->d_ino = entry.d_ino;
+  musl_entry->d_off = entry.d_off;
+  musl_entry->d_reclen = entry.d_reclen;
+  musl_entry->d_type = entry.d_type;
+
+  memset(musl_entry->d_name, 0, sizeof(musl_entry->d_name));
+  constexpr auto minlen =
+      std::min(sizeof(musl_entry->d_name), sizeof(entry.d_name));
+  memcpy(musl_entry->d_name, entry.d_name, minlen);
+  if (result == NULL) {
+    *musl_result = NULL;
+  } else {
+    *musl_result = musl_entry;
+  }
+  return 0;
+}

starboard/shared/modular/starboard_layer_posix_directory_abi_wrappers.h

@@ -0,0 +1,44 @@
+// Copyright 2024 The Cobalt Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef STARBOARD_SHARED_MODULAR_STARBOARD_LAYER_POSIX_DIRECTORY_ABI_WRAPPERS_H_
+#define STARBOARD_SHARED_MODULAR_STARBOARD_LAYER_POSIX_DIRECTORY_ABI_WRAPPERS_H_
+
+#include <dirent.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+#include "starboard/export.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct musl_dirent {
+  ino_t d_ino;
+  int64_t /* off_t */ d_off;
+  uint16_t /* short */ d_reclen;
+  unsigned char d_type;
+  char d_name[256];
+} musl_dirent;
+
+SB_EXPORT int __abi_wrap_readdir_r(DIR* dirp,
+                                   struct musl_dirent* entry,
+                                   struct musl_dirent** result);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // STARBOARD_SHARED_MODULAR_STARBOARD_LAYER_POSIX_DIRECTORY_ABI_WRAPPERS_H_