Ensure NIF term creation disallows illegal values

Add a check to enif_make_double to see if its double argument is
infinity or NaN, returning a badarg exception if it is. Change the
erl_nif documentation to specify that enif_make_double returns a
badarg exception if its double argument is either infinity or NaN. Add
tests to nif_SUITE for this change.

Add checks to the enif_make* functions for atoms to prevent the
creation of atoms whose name lengths are greater than the allowed
maximum atom length. The enif_make_atom and enif_make_atom_len
functions now return a badarg exception if the input string is too
long. The enif_make_existing_atom and enif_make_existing_atom_len
functions return false if the input string is too long. Change the
erl_nif documentation to reflect the changes to these functions. Add
tests to nif_SUITE for these changes.

Add a field to ErlNifEnv to track that a NIF has raised an exception
via enif_make_badarg. If a NIF calls enif_make_badarg but then ignores
its return value and instead tries to return a non-exception term as
its return value, the runtime still raises a badarg. This is needed to
prevent enif_make_badarg values resulting from calls to
enif_make_double, enif_make_atom, or enif_make_atom_len from being
erroneously stored within other terms and returned from a NIF. Calling
enif_make_badarg but not returning its return value has been
documented as being illegal ever since enif_make_badarg was added, but
the runtime has not enforced it until now. Add tests for regular and
dirty NIFs to ensure that calls to enif_make_badarg result in badarg
exceptions even if a NIF fails to return the result of
enif_make_badarg as its return value. Add documentation to
enif_make_badarg to specify that calling it raises a badarg even if a
NIF ignores its return value.

1 files changed, 1 insertions, 0 deletions

diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 32a2dc43e8..d58aecab9b 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -51,6 +51,7 @@ struct enif_environment_t /* ErlNifEnv */
     ErlHeapFragment* heap_frag;
     int fpe_was_unmasked;
     struct enif_tmp_obj_t* tmp_obj_list;
+    int exception_thrown; /* boolean */
 };
 extern void erts_pre_nif(struct enif_environment_t*, Process*,
 			 struct erl_module_nif*);