add user-modifiable recursion_limit
ceval.c:
define recurion_limit (static), default value is 2500
define Py_GetRecursionLimit and Py_SetRecursionLimit
raise RuntimeError if limit is exceeded
PC/config.h:
remove plat-specific definition
sysmodule.c:
add sys.(get|set)recursionlimit
diff --git a/Doc/lib/libsys.tex b/Doc/lib/libsys.tex
index bbea623..ac28e6f 100644
--- a/Doc/lib/libsys.tex
+++ b/Doc/lib/libsys.tex
@@ -148,6 +148,13 @@
(temporary) reference as an argument to \function{getrefcount()}.
\end{funcdesc}
+\begin{funcdesc}{getrecursionlimit}{}
+Return the current value of the recursion limit, the maximum depth of
+the Python interpreter stack. This limit prevents infinite recursion
+from causing an overflow of the C stack and crashing Python. It can
+be set by \function{setrecursionlimit}.
+\end{funcdesc}
+
\begin{datadesc}{hexversion}
The version number encoded as a single integer. This is guaranteed to
increase with each version, including proper support for
@@ -275,6 +282,17 @@
\index{profile function}
\index{profiler}
+\begin{funcdesc}{setrecursionlimit}{limit}
+Set the maximum depth of the Python interpreter stack to \var{limit}.
+This limit prevents infinite recursion from causing an overflow of the
+C stack and crashing Python.
+
+The highest possible limit is platform-dependent. A user may need to
+set the limit higher when she has a program that requires deep
+recursion and a platform that supports a higher limit. This should be
+done with care, because a too-high limit can lead to a crash.
+\edn{funcdesc}
+
\begin{funcdesc}{settrace}{tracefunc}
Set the system's trace function, which allows you to implement a
Python source code debugger in Python. See section ``How It Works''
diff --git a/PC/config.h b/PC/config.h
index a09899b..4a57199 100644
--- a/PC/config.h
+++ b/PC/config.h
@@ -443,13 +443,6 @@
#define SIZEOF_LONG 4
#define SIZEOF_LONG_LONG 8
-/* Smaller stack size limit. (9500 would work too, but we're conservative.) */
-
-#ifndef MAX_RECURSION_DEPTH
-#define MAX_RECURSION_DEPTH 5000
-#endif
-
-
/* EXPERIMENTAL FEATURE: When CHECK_IMPORT_CASE is defined, check case of
imported modules against case of file; this causes "import String" to fail
with a NameError exception when it finds "string.py". Normally, you set
diff --git a/Python/ceval.c b/Python/ceval.c
index b399b63..7e11250 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -298,6 +298,20 @@
}
+/* The interpreter's recursion limit */
+
+static int recursion_limit = 2500;
+
+int Py_GetRecursionLimit(void)
+{
+ return recursion_limit;
+}
+
+void Py_SetRecursionLimit(int new_limit)
+{
+ recursion_limit = new_limit;
+}
+
/* Status code for main loop (reason for stack unwind) */
enum why_code {
@@ -326,10 +340,6 @@
/* Interpreter main loop */
-#ifndef MAX_RECURSION_DEPTH
-#define MAX_RECURSION_DEPTH 10000
-#endif
-
static PyObject *
eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
PyObject **args, int argcount, PyObject **kws, int kwcount,
@@ -565,7 +575,7 @@
}
}
- if (++tstate->recursion_depth > MAX_RECURSION_DEPTH) {
+ if (++tstate->recursion_depth > recursion_limit) {
--tstate->recursion_depth;
PyErr_SetString(PyExc_RuntimeError,
"Maximum recursion depth exceeded");
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index d500a36..31d7abf 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -199,6 +199,45 @@
Tell the Python interpreter to check for asynchronous events every\n\
n instructions. This also affects how often thread switches occur.";
+static PyObject *
+sys_setrecursionlimit(PyObject *self, PyObject *args)
+{
+ int new_limit;
+ if (!PyArg_ParseTuple(args, "i:setrecursionlimit", &new_limit))
+ return NULL;
+ if (new_limit <= 0) {
+ PyErr_SetString(PyExc_ValueError,
+ "recursion limit must be positive");
+ return NULL;
+ }
+ Py_SetRecursionLimit(new_limit);
+ Py_INCREF(Py_None);
+ return Py_None;
+}
+
+static char setrecursionlimit_doc[] =
+"setrecursionlimit(n)\n\
+\n\
+Set the maximum depth of the Python interpreter stack to n. This\n\
+limit prevents infinite recursion from causing an overflow of the C\n\
+stack and crashing Python. The highest possible limit is platform-\n\
+dependent.";
+
+static PyObject *
+sys_getrecursionlimit(PyObject *self, PyObject *args)
+{
+ if (!PyArg_ParseTuple(args, ":getrecursionlimit"))
+ return NULL;
+ return PyInt_FromLong(Py_GetRecursionLimit());
+}
+
+static char getrecursionlimit_doc[] =
+"getrecursionlimit()\n\
+\n\
+Return the current value of the recursion limit, the maximum depth\n\
+of the Python interpreter stack. This limit prevents infinite\n\
+recursion from causing an overflow of the C stack and crashing Python.";
+
#ifdef USE_MALLOPT
/* Link with -lmalloc (or -lmpc) on an SGI */
#include <malloc.h>
@@ -268,7 +307,8 @@
/* Might as well keep this in alphabetic order */
{"exc_info", sys_exc_info, 1, exc_info_doc},
{"exit", sys_exit, 0, exit_doc},
- {"getdefaultencoding", sys_getdefaultencoding, 1, getdefaultencoding_doc},
+ {"getdefaultencoding", sys_getdefaultencoding, 1,
+ getdefaultencoding_doc},
#ifdef COUNT_ALLOCS
{"getcounts", sys_getcounts, 1},
#endif
@@ -280,12 +320,18 @@
{"gettotalrefcount", sys_gettotalrefcount, 1},
#endif
{"getrefcount", sys_getrefcount, 1, getrefcount_doc},
+ {"getrecursionlimit", sys_getrecursionlimit, 1,
+ getrecursionlimit_doc},
#ifdef USE_MALLOPT
{"mdebug", sys_mdebug, 1},
#endif
- {"setdefaultencoding", sys_setdefaultencoding, 1, setdefaultencoding_doc},
- {"setcheckinterval", sys_setcheckinterval, 1, setcheckinterval_doc},
+ {"setdefaultencoding", sys_setdefaultencoding, 1,
+ setdefaultencoding_doc},
+ {"setcheckinterval", sys_setcheckinterval, 1,
+ setcheckinterval_doc},
{"setprofile", sys_setprofile, 0, setprofile_doc},
+ {"setrecursionlimit", sys_setrecursionlimit, 1,
+ setrecursionlimit_doc},
{"settrace", sys_settrace, 0, settrace_doc},
{NULL, NULL} /* sentinel */
};
@@ -376,8 +422,10 @@
exc_info() -- return thread-safe information about the current exception\n\
exit() -- exit the interpreter by raising SystemExit\n\
getrefcount() -- return the reference count for an object (plus one :-)\n\
+getrecursionlimit() -- return the max recursion depth for the interpreter\n\
setcheckinterval() -- control how often the interpreter checks for events\n\
setprofile() -- set the global profiling function\n\
+setrecursionlimit() -- set the max recursion depth for the interpreter\n\
settrace() -- set the global debug tracing function\n\
"
#endif