diff options
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | generic/tclExecute.c | 44 |
2 files changed, 41 insertions, 10 deletions
@@ -1,3 +1,10 @@ +2001-03-02 Donal K. Fellows <fellowsd@cs.man.ac.uk> + + * generic/tclExecute.c (TclExecuteByteCode): Fixed bug that could + pass pointers to freed memory to command implementations, which + most obviously caused some weird behaviour with [info level], but + could have caused problems with user code and command traces too. + 2001-02-23 msofer <msofer@users.sourceforge.net> * no changes; fixing up the missing comment in the previous one. Sorry. diff --git a/generic/tclExecute.c b/generic/tclExecute.c index 97db9a2..156c4b1 100644 --- a/generic/tclExecute.c +++ b/generic/tclExecute.c @@ -10,7 +10,7 @@ * See the file "license.terms" for information on usage and redistribution * of this file, and for a DISCLAIMER OF ALL WARRANTIES. * - * RCS: @(#) $Id: tclExecute.c,v 1.18 2000/12/14 22:24:46 dgp Exp $ + * RCS: @(#) $Id: tclExecute.c,v 1.19 2001/03/02 15:31:15 dkf Exp $ */ #include "tclInt.h" @@ -438,7 +438,7 @@ void TclDeleteExecEnv(eePtr) ExecEnv *eePtr; /* Execution environment to free. */ { - ckfree((char *) eePtr->stackPtr); + Tcl_EventuallyFree(eePtr->stackPtr, TCL_DYNAMIC); ckfree((char *) eePtr); } @@ -508,7 +508,7 @@ GrowEvaluationStack(eePtr) memcpy((VOID *) newStackPtr, (VOID *) eePtr->stackPtr, (size_t) currBytes); - ckfree((char *) eePtr->stackPtr); + Tcl_EventuallyFree(eePtr->stackPtr, TCL_DYNAMIC); eePtr->stackPtr = newStackPtr; eePtr->stackEnd = (newElems - 1); /* i.e. index of last usable item */ } @@ -745,15 +745,19 @@ TclExecuteByteCode(interp, codePtr) Tcl_Obj **objv; /* The array of argument objects. */ Command *cmdPtr; /* Points to command's Command struct. */ int newPcOffset; /* New inst offset for break, continue. */ + Tcl_Obj **preservedStack; + /* Reference to memory block containing + * objv array (must be kept live throughout + * trace and command invokations.) */ #ifdef TCL_COMPILE_DEBUG int isUnknownCmd = 0; char cmdNameBuf[21]; #endif /* TCL_COMPILE_DEBUG */ - + /* * If the interpreter was deleted, return an error. */ - + if (iPtr->flags & DELETED) { Tcl_ResetResult(interp); Tcl_AppendToObj(Tcl_GetObjResult(interp), @@ -764,7 +768,7 @@ TclExecuteByteCode(interp, codePtr) result = TCL_ERROR; goto checkForCatch; } - + /* * Find the procedure to execute this command. If the * command is not found, handle it with the "unknown" proc. @@ -796,14 +800,26 @@ TclExecuteByteCode(interp, codePtr) objv[0] = Tcl_NewStringObj("unknown", -1); Tcl_IncrRefCount(objv[0]); } - + + /* + * A reference to part of the stack vector itself + * escapes our control, so must use preserve/release + * to stop it from being deallocated by a recursive + * call to ourselves. The extra variable is needed + * because all others are liable to change due to the + * trace procedures. + */ + + Tcl_Preserve(stackPtr); + preservedStack = stackPtr; + /* * Call any trace procedures. */ if (iPtr->tracePtr != NULL) { Trace *tracePtr, *nextTracePtr; - + for (tracePtr = iPtr->tracePtr; tracePtr != NULL; tracePtr = nextTracePtr) { nextTracePtr = tracePtr->nextPtr; @@ -820,14 +836,14 @@ TclExecuteByteCode(interp, codePtr) } } } - + /* * Finally, invoke the command's Tcl_ObjCmdProc. First reset * the interpreter's string and object results to their * default empty values since they could have gotten changed * by earlier invocations. */ - + Tcl_ResetResult(interp); if (tclTraceExec >= 2) { #ifdef TCL_COMPILE_DEBUG @@ -863,6 +879,14 @@ TclExecuteByteCode(interp, codePtr) CACHE_STACK_INFO(); /* + * If the old stack is going to be released, it is + * safe to do so now, since no references to objv are + * going to be used from now on. + */ + + Tcl_Release(preservedStack); + + /* * If the interpreter has a non-empty string result, the * result object is either empty or stale because some * procedure set interp->result directly. If so, move the |