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https://github.com/samba-team/samba.git
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7579e08599
This way talloc_stackframe() can benefit from a pool put on the stack further
up. No need to remove talloc_stackframe().
(This used to be commit be6fe38116)
131 lines
3.2 KiB
C
131 lines
3.2 KiB
C
/*
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Unix SMB/CIFS implementation.
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Implement a stack of talloc contexts
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Copyright (C) Volker Lendecke 2007
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/*
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* Implement a stack of talloc frames.
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*
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* When a new talloc stackframe is allocated with talloc_stackframe(), then
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* the TALLOC_CTX returned with talloc_tos() is reset to that new
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* frame. Whenever that stack frame is TALLOC_FREE()'ed, then the reverse
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* happens: The previous talloc_tos() is restored.
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*
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* This API is designed to be robust in the sense that if someone forgets to
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* TALLOC_FREE() a stackframe, then the next outer one correctly cleans up and
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* resets the talloc_tos().
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*
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* This robustness feature means that we can't rely on a linked list with
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* talloc destructors because in a hierarchy of talloc destructors the parent
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* destructor is called before its children destructors. The child destructor
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* called after the parent would set the talloc_tos() to the wrong value.
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*/
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#include "includes.h"
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static int talloc_stacksize;
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static int talloc_stack_arraysize;
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static TALLOC_CTX **talloc_stack;
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static int talloc_pop(TALLOC_CTX *frame)
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{
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int i;
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for (i=talloc_stacksize-1; i>0; i--) {
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if (frame == talloc_stack[i]) {
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break;
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}
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talloc_free(talloc_stack[i]);
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}
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talloc_stacksize = i;
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return 0;
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}
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/*
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* Create a new talloc stack frame.
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*
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* When free'd, it frees all stack frames that were created after this one and
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* not explicitly freed.
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*/
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static TALLOC_CTX *talloc_stackframe_internal(size_t poolsize)
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{
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TALLOC_CTX **tmp, *top, *parent;
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if (talloc_stack_arraysize < talloc_stacksize + 1) {
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tmp = TALLOC_REALLOC_ARRAY(NULL, talloc_stack, TALLOC_CTX *,
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talloc_stacksize + 1);
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if (tmp == NULL) {
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goto fail;
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}
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talloc_stack = tmp;
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talloc_stack_arraysize = talloc_stacksize + 1;
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}
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if (talloc_stacksize == 0) {
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parent = talloc_stack;
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}
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else {
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parent = talloc_stack[talloc_stacksize-1];
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}
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if (poolsize) {
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top = talloc_pool(parent, poolsize);
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} else {
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top = talloc_new(parent);
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}
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if (top == NULL) {
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goto fail;
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}
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talloc_set_destructor(top, talloc_pop);
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talloc_stack[talloc_stacksize++] = top;
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return top;
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fail:
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smb_panic("talloc_stackframe failed");
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return NULL;
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}
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TALLOC_CTX *talloc_stackframe(void)
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{
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return talloc_stackframe_internal(0);
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}
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TALLOC_CTX *talloc_stackframe_pool(size_t poolsize)
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{
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return talloc_stackframe_internal(poolsize);
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}
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/*
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* Get us the current top of the talloc stack.
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*/
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TALLOC_CTX *talloc_tos(void)
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{
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if (talloc_stacksize == 0) {
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talloc_stackframe();
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DEBUG(0, ("no talloc stackframe around, leaking memory\n"));
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}
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return talloc_stack[talloc_stacksize-1];
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}
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