Guard against changes in the list size during a compare or sort.
This commit is contained in:
Guido van Rossum
parent
578de30fd7
commit
ae621ff7b7
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@ -283,9 +283,8 @@ static int
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list_compare(v, w)
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PyListObject *v, *w;
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{
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int len = (v->ob_size < w->ob_size) ? v->ob_size : w->ob_size;
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int i;
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for (i = 0; i < len; i++) {
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for (i = 0; i < v->ob_size && i < w->ob_size; i++) {
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int cmp = PyObject_Compare(v->ob_item[i], w->ob_item[i]);
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if (cmp != 0)
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return cmp;
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@ -587,11 +586,14 @@ listappend(self, args)
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function is NULL. */
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static int
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docompare(x, y, compare)
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docompare(x, y, compare, list)
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PyObject *x;
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PyObject *y;
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PyObject *compare;
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PyListObject *list;
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{
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int size = list->ob_size; /* Number of elements to sort */
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PyObject **array = list->ob_item; /* Start of array to sort */
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PyObject *args, *res;
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int i;
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@ -599,6 +601,11 @@ docompare(x, y, compare)
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i = PyObject_Compare(x, y);
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if (i && PyErr_Occurred())
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i = CMPERROR;
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else if (size != list->ob_size || array != list->ob_item) {
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PyErr_SetString(PyExc_SystemError,
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"list changed size during sort");
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i = CMPERROR;
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}
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return i;
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}
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@ -615,6 +622,11 @@ docompare(x, y, compare)
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"comparison function should return int");
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return CMPERROR;
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}
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if (size != list->ob_size || array != list->ob_item) {
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PyErr_SetString(PyExc_SystemError,
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"list changed size during sort");
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return CMPERROR;
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}
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i = PyInt_AsLong(res);
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Py_DECREF(res);
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if (i < 0)
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@ -643,11 +655,12 @@ docompare(x, y, compare)
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(i.e. no items have been removed or duplicated). */
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static int
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quicksort(array, size, compare)
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PyObject **array; /* Start of array to sort */
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int size; /* Number of elements to sort */
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quicksort(list, compare)
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PyListObject *list; /* List to sort */
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PyObject *compare;/* Comparison function object, or NULL for default */
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{
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int size = list->ob_size; /* Number of elements to sort */
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PyObject **array = list->ob_item; /* Start of array to sort */
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register PyObject *tmp, *pivot;
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register PyObject **l, **r, **p;
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PyObject **lo, **hi, **notp;
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@ -675,7 +688,8 @@ quicksort(array, size, compare)
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pivot = *r;
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do {
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p = l + ((r - l) >> 1);
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k = docompare(pivot, *p, compare);
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k = docompare(pivot, *p,
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compare, list);
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if (k == CMPERROR)
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return -1;
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if (k < 0)
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@ -699,19 +713,19 @@ quicksort(array, size, compare)
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p = lo + (n>>1); /* Middle */
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r = hi - 1; /* Last */
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k = docompare(*p, *l, compare);
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k = docompare(*p, *l, compare, list);
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if (k == CMPERROR)
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return -1;
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if (k < 0)
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{ tmp = *p; *p = *l; *l = tmp; }
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k = docompare(*r, *p, compare);
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k = docompare(*r, *p, compare, list);
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if (k == CMPERROR)
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return -1;
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if (k < 0)
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{ tmp = *r; *r = *p; *p = tmp; }
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k = docompare(*p, *l, compare);
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k = docompare(*p, *l, compare, list);
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if (k == CMPERROR)
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return -1;
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if (k < 0)
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@ -727,7 +741,7 @@ quicksort(array, size, compare)
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/* Move left index to element >= pivot */
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while (l < p) {
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k = docompare(*l, pivot, compare);
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k = docompare(*l, pivot, compare, list);
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if (k == CMPERROR)
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return -1;
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if (k < 0)
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@ -739,7 +753,7 @@ quicksort(array, size, compare)
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}
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/* Move right index to element <= pivot */
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while (r > p) {
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k = docompare(pivot, *r, compare);
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k = docompare(pivot, *r, compare, list);
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if (k == CMPERROR)
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return -1;
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if (k < 0)
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@ -804,7 +818,7 @@ quicksort(array, size, compare)
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* This wastes a compare if it fails, but can win big
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* when there are runs of duplicates.
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*/
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k = docompare(pivot, *l, compare);
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k = docompare(pivot, *l, compare, list);
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if (k == CMPERROR)
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return -1;
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if (!(k < 0)) {
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@ -817,7 +831,7 @@ quicksort(array, size, compare)
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*/
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while (r > lo) {
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/* because r-1 < p, *(r-1) <= pivot is known */
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k = docompare(*(r-1), pivot, compare);
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k = docompare(*(r-1), pivot, compare, list);
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if (k == CMPERROR)
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return -1;
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if (k < 0)
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@ -829,7 +843,7 @@ quicksort(array, size, compare)
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l++;
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while (l < hi) {
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/* because l > p, pivot <= *l is known */
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k = docompare(pivot, *l, compare);
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k = docompare(pivot, *l, compare, list);
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if (k == CMPERROR)
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return -1;
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if (k < 0)
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@ -866,8 +880,7 @@ listsort(self, compare)
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PyListObject *self;
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PyObject *compare;
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{
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/* XXX Don't you *dare* changing the list's length in compare()! */
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if (quicksort(self->ob_item, self->ob_size, compare) < 0)
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if (quicksort(self, compare) < 0)
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return NULL;
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Py_INCREF(Py_None);
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return Py_None;
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@ -922,11 +935,7 @@ PyList_Sort(v)
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PyErr_BadInternalCall();
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return -1;
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}
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v = listsort((PyListObject *)v, (PyObject *)NULL);
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if (v == NULL)
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return -1;
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Py_DECREF(v);
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return 0;
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return quicksort((PyListObject *)v, (PyObject *)NULL);
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}
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PyObject *
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