Introduce and use `caml_ext_table_add_noexc` (#12202)

Same functionality as `caml_ext_table_add`, but returns -1 when running
out of memory instead of raising an exception.

Use the new function in `caml_read_directory`, which must not raise exceptions
since it is called from blocking sections.  Instead, `caml_read_directory`
returns an error code if `caml_ext_table_add_noexc` runs out of memory.

Also: harden `caml_ext_table_add{,_noexc}` against integer overflow
when computing the new table size for resizing.

Fixes: #10403

1 files changed, 3 insertions, 1 deletions

diff --git a/runtime/win32.c b/runtime/win32.c
index 70c90f7a11..599805145f 100644
--- a/runtime/win32.c
+++ b/runtime/win32.c
@@ -445,7 +445,9 @@ CAMLexport int caml_read_directory(wchar_t * dirname,
   }
   do {
     if (wcscmp(fileinfo.name, L".") != 0 && wcscmp(fileinfo.name, L"..") != 0) {
-      caml_ext_table_add(contents, caml_stat_strdup_of_utf16(fileinfo.name));
+      res = caml_ext_table_add_noexc(contents,
+                                     caml_stat_strdup_of_utf16(fileinfo.name));
+      if (res == -1) { _findclose(h); errno = ENOMEM; return -1; }
     }
   } while (_wfindnext(h, &fileinfo) == 0);
   _findclose(h);