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Fixed issue #5122: Synchronize tk load failure check to prevent a

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potential deadlock.
This commit is contained in:
Guilherme Polo 2009-02-09 20:50:27 +00:00
parent 55bdb8e4ac
commit a66cf5bd04
4 changed files with 124 additions and 29 deletions
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87
Modules/_tkinter.c
View file

@ -33,6 +33,8 @@ Copyright (C) 1994 Steen Lumholt.
#include <windows.h>
#endif
#include "tkinter.h"
/* Allow using this code in Python 2.[12] */
#ifndef PyDoc_STRVAR
#define PyDoc_STRVAR(name,str) static char name[] = str
@ -74,9 +76,7 @@ Copyright (C) 1994 Steen Lumholt.
#define CONST
#endif
#define TKMAJORMINOR (TK_MAJOR_VERSION*1000 + TK_MINOR_VERSION)
#if TKMAJORMINOR < 8002
#if TK_VERSION_HEX < 0x08020002
#error "Tk older than 8.2 not supported"
#endif
@ -280,6 +280,9 @@ static PyObject *excInCmd;
static PyObject *valInCmd;
static PyObject *trbInCmd;
#ifdef TKINTER_PROTECT_LOADTK
static int tk_load_failed;
#endif
static PyObject *
@ -555,21 +558,35 @@ SplitObj(PyObject *arg)
int
Tcl_AppInit(Tcl_Interp *interp)
{
Tk_Window main;
const char * _tkinter_skip_tk_init;
if (Tcl_Init(interp) == TCL_ERROR) {
PySys_WriteStderr("Tcl_Init error: %s\n", Tcl_GetStringResult(interp));
return TCL_ERROR;
}
_tkinter_skip_tk_init = Tcl_GetVar(interp, "_tkinter_skip_tk_init", TCL_GLOBAL_ONLY);
if (_tkinter_skip_tk_init == NULL || strcmp(_tkinter_skip_tk_init, "1") != 0) {
main = Tk_MainWindow(interp);
if (Tk_Init(interp) == TCL_ERROR) {
PySys_WriteStderr("Tk_Init error: %s\n", Tcl_GetStringResult(interp));
return TCL_ERROR;
}
_tkinter_skip_tk_init = Tcl_GetVar(interp,
"_tkinter_skip_tk_init", TCL_GLOBAL_ONLY);
if (_tkinter_skip_tk_init != NULL &&
strcmp(_tkinter_skip_tk_init, "1") == 0) {
return TCL_OK;
}
#ifdef TKINTER_PROTECT_LOADTK
if (tk_load_failed) {
PySys_WriteStderr("Tk_Init error: %s\n", TKINTER_LOADTK_ERRMSG);
return TCL_ERROR;
}
#endif
if (Tk_Init(interp) == TCL_ERROR) {
#ifdef TKINTER_PROTECT_LOADTK
tk_load_failed = 1;
#endif
PySys_WriteStderr("Tk_Init error: %s\n", Tcl_GetStringResult(interp));
return TCL_ERROR;
}
return TCL_OK;
}
#endif /* !WITH_APPINIT */
@ -652,8 +669,15 @@ Tkapp_New(char *screenName, char *baseName, char *className,
ckfree(argv0);
if (! wantTk) {
Tcl_SetVar(v->interp, "_tkinter_skip_tk_init", "1", TCL_GLOBAL_ONLY);
Tcl_SetVar(v->interp,
"_tkinter_skip_tk_init", "1", TCL_GLOBAL_ONLY);
}
#ifdef TKINTER_PROTECT_LOADTK
else if (tk_load_failed) {
Tcl_SetVar(v->interp,
"_tkinter_tk_failed", "1", TCL_GLOBAL_ONLY);
}
#endif
/* some initial arguments need to be in argv */
if (sync || use) {
@ -688,6 +712,18 @@ Tkapp_New(char *screenName, char *baseName, char *className,
if (Tcl_AppInit(v->interp) != TCL_OK) {
PyObject *result = Tkinter_Error((PyObject *)v);
#ifdef TKINTER_PROTECT_LOADTK
if (wantTk) {
const char *_tkinter_tk_failed;
_tkinter_tk_failed = Tcl_GetVar(v->interp,
"_tkinter_tk_failed", TCL_GLOBAL_ONLY);
if ( _tkinter_tk_failed != NULL &&
strcmp(_tkinter_tk_failed, "1") == 0) {
tk_load_failed = 1;
}
}
#endif
Py_DECREF((PyObject *)v);
return (TkappObject *)result;
}
@ -2669,23 +2705,22 @@ Tkapp_InterpAddr(PyObject *self, PyObject *args)
static PyObject *
Tkapp_TkInit(PyObject *self, PyObject *args)
{
static int has_failed;
Tcl_Interp *interp = Tkapp_Interp(self);
Tk_Window main_window;
const char * _tk_exists = NULL;
int err;
main_window = Tk_MainWindow(interp);
/* In all current versions of Tk (including 8.4.13), Tk_Init
deadlocks on the second call when the first call failed.
To avoid the deadlock, we just refuse the second call through
a static variable. */
if (has_failed) {
PyErr_SetString(Tkinter_TclError,
"Calling Tk_Init again after a previous call failed might deadlock");
#ifdef TKINTER_PROTECT_LOADTK
/* Up to Tk 8.4.13, Tk_Init deadlocks on the second call when the
* first call failed.
* To avoid the deadlock, we just refuse the second call through
* a static variable.
*/
if (tk_load_failed) {
PyErr_SetString(Tkinter_TclError, TKINTER_LOADTK_ERRMSG);
return NULL;
}
#endif
/* We want to guard against calling Tk_Init() multiple times */
CHECK_TCL_APPARTMENT;
ENTER_TCL
@ -2704,8 +2739,10 @@ Tkapp_TkInit(PyObject *self, PyObject *args)
}
if (_tk_exists == NULL || strcmp(_tk_exists, "1") != 0) {
if (Tk_Init(interp) == TCL_ERROR) {
PyErr_SetString(Tkinter_TclError, Tcl_GetStringResult(Tkapp_Interp(self)));
has_failed = 1;
PyErr_SetString(Tkinter_TclError, Tcl_GetStringResult(Tkapp_Interp(self)));
#ifdef TKINTER_PROTECT_LOADTK
tk_load_failed = 1;
#endif
return NULL;
}
}