Random number generator in Python core

Python/pythonrun.c

 
 /* Python interpreter top-level routines, including init/exit */
 
 #include "Python.h"
 
 #include "Python-ast.h"
 #undef Yield /* undefine macro conflicting with winbase.h */
 #include "grammar.h"
 #include "node.h"
 #include "token.h"
@@ skipping 55 matching lines @@
 static void initsigs(void);
 static void call_py_exitfuncs(void);
 static void wait_for_thread_shutdown(void);
 static void call_ll_exitfuncs(void);
 extern int _PyUnicode_Init(void);
 extern void _PyUnicode_Fini(void);
 extern int _PyLong_Init(void);
 extern void PyLong_Fini(void);
 extern int _PyFaulthandler_Init(void);
 extern void _PyFaulthandler_Fini(void);
+extern void _Py_InitRndHashSeed(void);
 
 #ifdef WITH_THREAD
 extern void _PyGILState_Init(PyInterpreterState *, PyThreadState *);
 extern void _PyGILState_Fini(void);
 #endif /* WITH_THREAD */
 
 int Py_DebugFlag; /* Needed by parser.c */
 int Py_VerboseFlag; /* Needed by import.c */
 int Py_QuietFlag; /* Needed by sysmodule.c */
 int Py_InteractiveFlag; /* Needed by Py_FdIsInteractive() below */
 int Py_InspectFlag; /* Needed to determine whether to exit at SystemExit */
 int Py_NoSiteFlag; /* Suppress 'import site' */
 int Py_BytesWarningFlag; /* Warn on str(bytes) and str(buffer) */
 int Py_DontWriteBytecodeFlag; /* Suppress writing bytecode files (*.py[co]) */
 int Py_UseClassExceptionsFlag = 1; /* Needed by bltinmodule.c: deprecated */
 int Py_FrozenFlag; /* Needed by getpath.c */
 int Py_IgnoreEnvironmentFlag; /* e.g. PYTHONPATH, PYTHONHOME */
 int Py_NoUserSiteDirectory = 0; /* for -s and site.py */
 int Py_UnbufferedStdioFlag = 0; /* Unbuffered binary std{in,out,err} */
+int Py_NoRandomHashFlag = 0; /* Don't use randomized hashes */
 
 PyThreadState *_Py_Finalizing = NULL;
+
 
 /* PyModule_GetWarningsModule is no longer necessary as of 2.6
 since _warnings is builtin.  This API should not be used. */
 PyObject *
 PyModule_GetWarningsModule(void)
 {
     return PyImport_ImportModule("warnings");
 }
 
 static int initialized = 0;
@@ skipping 104 matching lines @@
 #endif
 
     if ((p = Py_GETENV("PYTHONDEBUG")) && *p != '\0')
         Py_DebugFlag = add_flag(Py_DebugFlag, p);
     if ((p = Py_GETENV("PYTHONVERBOSE")) && *p != '\0')
         Py_VerboseFlag = add_flag(Py_VerboseFlag, p);
     if ((p = Py_GETENV("PYTHONOPTIMIZE")) && *p != '\0')
         Py_OptimizeFlag = add_flag(Py_OptimizeFlag, p);
     if ((p = Py_GETENV("PYTHONDONTWRITEBYTECODE")) && *p != '\0')
         Py_DontWriteBytecodeFlag = add_flag(Py_DontWriteBytecodeFlag, p);
+    if ((p = Py_GETENV("PYTHONNORANDOMHASH")) && *p != '\0')
+        Py_NoRandomHashFlag = add_flag(Py_NoRandomHashFlag, p);
+
+    if (!Py_NoRandomHashFlag) {
+        _Py_InitRndHashSeed();
+    }
 
     interp = PyInterpreterState_New();
     if (interp == NULL)
         Py_FatalError("Py_Initialize: can't make first interpreter");
 
     tstate = PyThreadState_New(interp);
     if (tstate == NULL)
         Py_FatalError("Py_Initialize: can't make first thread");
     (void) PyThreadState_Swap(tstate);
 
@@ skipping 2330 matching lines @@
 #undef PyRun_InteractiveLoop
 PyAPI_FUNC(int)
 PyRun_InteractiveLoop(FILE *f, const char *p)
 {
     return PyRun_InteractiveLoopFlags(f, p, NULL);
 }
 
 #ifdef __cplusplus
 }
 #endif