1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
/*
Unix SMB/CIFS implementation.
Implement a stack of talloc contexts
Copyright (C) Volker Lendecke 2007
Copyright (C) Jeremy Allison 2009 - made thread safe.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* Implement a stack of talloc frames.
*
* When a new talloc stackframe is allocated with talloc_stackframe(), then
* the TALLOC_CTX returned with talloc_tos() is reset to that new
* frame. Whenever that stack frame is TALLOC_FREE()'ed, then the reverse
* happens: The previous talloc_tos() is restored.
*
* This API is designed to be robust in the sense that if someone forgets to
* TALLOC_FREE() a stackframe, then the next outer one correctly cleans up and
* resets the talloc_tos().
*
* This robustness feature means that we can't rely on a linked list with
* talloc destructors because in a hierarchy of talloc destructors the parent
* destructor is called before its children destructors. The child destructor
* called after the parent would set the talloc_tos() to the wrong value.
*/
#include "includes.h"
struct talloc_stackframe {
int talloc_stacksize;
int talloc_stack_arraysize;
TALLOC_CTX **talloc_stack;
};
/*
* In the single threaded case this is a pointer
* to the global talloc_stackframe. In the MT-case
* this is the pointer to the thread-specific key
* used to look up the per-thread talloc_stackframe
* pointer.
*/
static void *global_ts;
/* Variable to ensure TLS value is only initialized once. */
static smb_thread_once_t ts_initialized = SMB_THREAD_ONCE_INIT;
static void talloc_stackframe_init(void * unused)
{
if (SMB_THREAD_CREATE_TLS("talloc_stackframe", global_ts)) {
smb_panic("talloc_stackframe_init create_tls failed");
}
}
static struct talloc_stackframe *talloc_stackframe_create(void)
{
#if defined(PARANOID_MALLOC_CHECKER)
#ifdef calloc
#undef calloc
#endif
#endif
struct talloc_stackframe *ts = (struct talloc_stackframe *)calloc(
1, sizeof(struct talloc_stackframe));
#if defined(PARANOID_MALLOC_CHECKER)
#define calloc(n, s) __ERROR_DONT_USE_MALLOC_DIRECTLY
#endif
if (!ts) {
smb_panic("talloc_stackframe_init malloc failed");
}
SMB_THREAD_ONCE(&ts_initialized, talloc_stackframe_init, NULL);
if (SMB_THREAD_SET_TLS(global_ts, ts)) {
smb_panic("talloc_stackframe_init set_tls failed");
}
return ts;
}
static int talloc_pop(TALLOC_CTX *frame)
{
struct talloc_stackframe *ts =
(struct talloc_stackframe *)SMB_THREAD_GET_TLS(global_ts);
int i;
for (i=ts->talloc_stacksize-1; i>0; i--) {
if (frame == ts->talloc_stack[i]) {
break;
}
TALLOC_FREE(ts->talloc_stack[i]);
}
ts->talloc_stack[i] = NULL;
ts->talloc_stacksize = i;
return 0;
}
/*
* Create a new talloc stack frame.
*
* When free'd, it frees all stack frames that were created after this one and
* not explicitly freed.
*/
static TALLOC_CTX *talloc_stackframe_internal(size_t poolsize)
{
TALLOC_CTX **tmp, *top, *parent;
struct talloc_stackframe *ts =
(struct talloc_stackframe *)SMB_THREAD_GET_TLS(global_ts);
if (ts == NULL) {
ts = talloc_stackframe_create();
}
if (ts->talloc_stack_arraysize < ts->talloc_stacksize + 1) {
tmp = talloc_realloc(NULL, ts->talloc_stack, TALLOC_CTX *,
ts->talloc_stacksize + 1);
if (tmp == NULL) {
goto fail;
}
ts->talloc_stack = tmp;
ts->talloc_stack_arraysize = ts->talloc_stacksize + 1;
}
if (ts->talloc_stacksize == 0) {
parent = ts->talloc_stack;
} else {
parent = ts->talloc_stack[ts->talloc_stacksize-1];
}
if (poolsize) {
top = talloc_pool(parent, poolsize);
} else {
top = talloc_new(parent);
}
if (top == NULL) {
goto fail;
}
talloc_set_destructor(top, talloc_pop);
ts->talloc_stack[ts->talloc_stacksize++] = top;
return top;
fail:
smb_panic("talloc_stackframe failed");
return NULL;
}
TALLOC_CTX *talloc_stackframe(void)
{
return talloc_stackframe_internal(0);
}
TALLOC_CTX *talloc_stackframe_pool(size_t poolsize)
{
return talloc_stackframe_internal(poolsize);
}
/*
* Get us the current top of the talloc stack.
*/
TALLOC_CTX *talloc_tos(void)
{
struct talloc_stackframe *ts =
(struct talloc_stackframe *)SMB_THREAD_GET_TLS(global_ts);
if (ts == NULL || ts->talloc_stacksize == 0) {
talloc_stackframe();
ts = (struct talloc_stackframe *)SMB_THREAD_GET_TLS(global_ts);
DEBUG(0, ("no talloc stackframe around, leaking memory\n"));
}
return ts->talloc_stack[ts->talloc_stacksize-1];
}
|
