From a66cf5bd04d40f3b0515dd43a1f337092f1df3cd Mon Sep 17 00:00:00 2001 From: Guilherme Polo Date: Mon, 9 Feb 2009 20:50:27 +0000 Subject: Fixed issue #5122: Synchronize tk load failure check to prevent a potential deadlock. --- Misc/NEWS | 3 ++ Modules/_tkinter.c | 89 +++++++++++++++++++++++++++++++++++++---------------- Modules/tkappinit.c | 38 ++++++++++++++++++++--- Modules/tkinter.h | 25 +++++++++++++++ 4 files changed, 125 insertions(+), 30 deletions(-) create mode 100644 Modules/tkinter.h diff --git a/Misc/NEWS b/Misc/NEWS index 824b0d4..c51315a 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -152,6 +152,9 @@ Core and Builtins Library ------- +- Issue #5122: Synchronize tk load failure check to prevent a potential + deadlock. + - Issue #4890: Handle empty text search pattern in Tkinter.Text.search. - Issue #5170: Fixed Unicode output bug in logging and added test case. diff --git a/Modules/_tkinter.c b/Modules/_tkinter.c index 5b1de8c..62bcff4 100644 --- a/Modules/_tkinter.c +++ b/Modules/_tkinter.c @@ -33,6 +33,8 @@ Copyright (C) 1994 Steen Lumholt. #include #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; } } diff --git a/Modules/tkappinit.c b/Modules/tkappinit.c index de04b0d..cfbd20c 100644 --- a/Modules/tkappinit.c +++ b/Modules/tkappinit.c @@ -16,11 +16,21 @@ #include #include +#include "tkinter.h" + +#ifdef TKINTER_PROTECT_LOADTK +/* See Tkapp_TkInit in _tkinter.c for the usage of tk_load_faile */ +static int tk_load_failed; +#endif + int Tcl_AppInit(Tcl_Interp *interp) { Tk_Window main_window; - const char * _tkinter_skip_tk_init; + const char *_tkinter_skip_tk_init; +#ifdef TKINTER_PROTECT_LOADTK + const char *_tkinter_tk_failed; +#endif #ifdef TK_AQUA #ifndef MAX_PATH_LEN @@ -74,12 +84,32 @@ Tcl_AppInit(Tcl_Interp *interp) /* Initialize modules that don't require Tk */ #endif - _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) { + _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; } - if (Tk_Init(interp) == TCL_ERROR) + +#ifdef TKINTER_PROTECT_LOADTK + _tkinter_tk_failed = Tcl_GetVar(interp, + "_tkinter_tk_failed", TCL_GLOBAL_ONLY); + + if (tk_load_failed || ( + _tkinter_tk_failed != NULL && + strcmp(_tkinter_tk_failed, "1") == 0)) { + Tcl_SetResult(interp, TKINTER_LOADTK_ERRMSG, TCL_STATIC); + return TCL_ERROR; + } +#endif + + if (Tk_Init(interp) == TCL_ERROR) { +#ifdef TKINTER_PROTECT_LOADTK + tk_load_failed = 1; + Tcl_SetVar(interp, "_tkinter_tk_failed", "1", TCL_GLOBAL_ONLY); +#endif return TCL_ERROR; + } main_window = Tk_MainWindow(interp); diff --git a/Modules/tkinter.h b/Modules/tkinter.h new file mode 100644 index 0000000..57be878 --- /dev/null +++ b/Modules/tkinter.h @@ -0,0 +1,25 @@ +#ifndef TKINTER_H +#define TKINTER_H + +/* This header is used to share some macros between _tkinter.c and + * tkappinit.c */ + +/* TK_RELEASE_LEVEL is always one of the following: + * TCL_ALPHA_RELEASE 0 + * TCL_BETA_RELEASE 1 + * TCL_FINAL_RELEASE 2 + */ +#define TK_VERSION_HEX ((TK_MAJOR_VERSION << 24) | \ + (TK_MINOR_VERSION << 16) | \ + (TK_RELEASE_SERIAL << 8) | \ + (TK_RELEASE_LEVEL << 0)) + +/* Protect Tk 8.4.13 and older from a deadlock that happens when trying + * to load tk after a failed attempt. */ +#if TK_VERSION_HEX < 0x08040e02 +#define TKINTER_PROTECT_LOADTK +#define TKINTER_LOADTK_ERRMSG \ + "Calling Tk_Init again after a previous call failed might deadlock" +#endif + +#endif /* !TKINTER_H */ -- cgit v0.12