get some forbidden C/R API fruits

forbidden.c

#include <Rinternals.h>
#include <Rinterface.h>

extern void* R_GlobalContext ;

#define R_NO_REMAP
#define USE_RINTERNALS

#include <R.h>
#include <Rinternals.h>
#include <R_ext/Complex.h>
#include <R_ext/Parse.h>
#include <R_ext/Rdynload.h>
#include <R_ext/Callbacks.h>
#include <Rversion.h>

typedef SEXP (*CCODE)(SEXP, SEXP, SEXP, SEXP);
 
/* Information for Deparsing Expressions */
typedef enum {
    PP_INVALID  =  0,
    PP_ASSIGN   =  1,
    PP_ASSIGN2  =  2,
    PP_BINARY   =  3,
    PP_BINARY2  =  4,
    PP_BREAK    =  5,
    PP_CURLY    =  6,
    PP_FOR      =  7,
    PP_FUNCALL  =  8,
    PP_FUNCTION =  9,
    PP_IF     = 10,
    PP_NEXT     = 11,
    PP_PAREN    = 12,
    PP_RETURN   = 13,
    PP_SUBASS   = 14,
    PP_SUBSET   = 15,
    PP_WHILE     = 16,
    PP_UNARY     = 17,
    PP_DOLLAR     = 18,
    PP_FOREIGN     = 19,
    PP_REPEAT     = 20
} PPkind;
 
typedef enum {
    PREC_FN     = 0,
    PREC_LEFT    = 1,
    PREC_EQ     = 2,
    PREC_RIGHT     = 3,
    PREC_TILDE     = 4,
    PREC_OR     = 5,
    PREC_AND     = 6,
    PREC_NOT     = 7,
    PREC_COMPARE = 8,
    PREC_SUM     = 9,
    PREC_PROD     = 10,
    PREC_PERCENT = 11,
    PREC_COLON     = 12,
    PREC_SIGN     = 13,
    PREC_POWER     = 14,
    PREC_DOLLAR  = 15,
    PREC_NS     = 16,
    PREC_SUBSET     = 17
} PPprec;
 
typedef struct {
    PPkind kind;      /* deparse kind */
    PPprec precedence; /* operator precedence */
    unsigned int rightassoc;  /* right associative? */
} PPinfo;
 
typedef struct {
    char   *name;    /* print name */
    CCODE  cfun;     /* c-code address */
    int       code;     /* offset within c-code */
    int       eval;     /* evaluate args? */
    int       arity;    /* function arity */
    PPinfo gram;     /* pretty-print info */
} FUNTAB;
 
extern FUNTAB    R_FunTab[];        /* Built in functions */ 

SEXP get_forbidden_fruits(){
  SEXP res = PROTECT(allocVector(VECSXP,2)) ;
  
  // first : R_GlobalContext
  SEXP global_context = PROTECT(R_MakeExternalPtr(R_GlobalContext,R_NilValue,R_NilValue)) ;
  SET_VECTOR_ELT(res,0,global_context) ;
  
  // then R_FunTab
  SEXP fun_tab = PROTECT(R_MakeExternalPtr(R_FunTab,R_NilValue,R_NilValue)) ;
  SET_VECTOR_ELT(res,1,fun_tab) ;
  
  UNPROTECT(3) ;
  return res ;
}