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
|
/* Cleanup routines for GDB, the GNU debugger.
Copyright (C) 1986-2021 Free Software Foundation, Inc.
This file is part of GDB.
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 3 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, see <http://www.gnu.org/licenses/>. */
#include "common-defs.h"
#include "cleanups.h"
/* The cleanup list records things that have to be undone
if an error happens (descriptors to be closed, memory to be freed, etc.)
Each link in the chain records a function to call and an
argument to give it.
Use make_cleanup to add an element to the cleanup chain.
Use do_cleanups to do all cleanup actions back to a given
point in the chain. Use discard_cleanups to remove cleanups
from the chain back to a given point, not doing them.
If the argument is pointer to allocated memory, then you need
to additionally set the 'free_arg' member to a function that will
free that memory. This function will be called both when the cleanup
is executed and when it's discarded. */
struct cleanup
{
struct cleanup *next;
void (*function) (void *);
void (*free_arg) (void *);
void *arg;
};
/* Used to mark the end of a cleanup chain.
The value is chosen so that it:
- is non-NULL so that make_cleanup never returns NULL,
- causes a segv if dereferenced
[though this won't catch errors that a value of, say,
((struct cleanup *) -1) will]
- displays as something useful when printed in gdb.
This is const for a bit of extra robustness.
It is initialized to coax gcc into putting it into .rodata.
All fields are initialized to survive -Wextra. */
static const struct cleanup sentinel_cleanup = { 0, 0, 0, 0 };
/* Handy macro to use when referring to sentinel_cleanup. */
#define SENTINEL_CLEANUP ((struct cleanup *) &sentinel_cleanup)
/* Chain of cleanup actions established with make_final_cleanup,
to be executed when gdb exits. */
static struct cleanup *final_cleanup_chain = SENTINEL_CLEANUP;
/* Main worker routine to create a cleanup.
PMY_CHAIN is a pointer to either cleanup_chain or final_cleanup_chain.
FUNCTION is the function to call to perform the cleanup.
ARG is passed to FUNCTION when called.
FREE_ARG, if non-NULL, is called after the cleanup is performed.
The result is a pointer to the previous chain pointer
to be passed later to do_cleanups or discard_cleanups. */
static struct cleanup *
make_my_cleanup2 (struct cleanup **pmy_chain, make_cleanup_ftype *function,
void *arg, void (*free_arg) (void *))
{
struct cleanup *newobj = XNEW (struct cleanup);
struct cleanup *old_chain = *pmy_chain;
newobj->next = *pmy_chain;
newobj->function = function;
newobj->free_arg = free_arg;
newobj->arg = arg;
*pmy_chain = newobj;
gdb_assert (old_chain != NULL);
return old_chain;
}
/* Worker routine to create a cleanup without a destructor.
PMY_CHAIN is a pointer to either cleanup_chain or final_cleanup_chain.
FUNCTION is the function to call to perform the cleanup.
ARG is passed to FUNCTION when called.
The result is a pointer to the previous chain pointer
to be passed later to do_cleanups or discard_cleanups. */
static struct cleanup *
make_my_cleanup (struct cleanup **pmy_chain, make_cleanup_ftype *function,
void *arg)
{
return make_my_cleanup2 (pmy_chain, function, arg, NULL);
}
/* Add a new cleanup to the final cleanup_chain,
and return the previous chain pointer
to be passed later to do_cleanups or discard_cleanups.
Args are FUNCTION to clean up with, and ARG to pass to it. */
struct cleanup *
make_final_cleanup (make_cleanup_ftype *function, void *arg)
{
return make_my_cleanup (&final_cleanup_chain, function, arg);
}
/* Worker routine to perform cleanups.
PMY_CHAIN is a pointer to either cleanup_chain or final_cleanup_chain.
OLD_CHAIN is the result of a "make" cleanup routine.
Cleanups are performed until we get back to the old end of the chain. */
static void
do_my_cleanups (struct cleanup **pmy_chain,
struct cleanup *old_chain)
{
struct cleanup *ptr;
while ((ptr = *pmy_chain) != old_chain)
{
*pmy_chain = ptr->next; /* Do this first in case of recursion. */
(*ptr->function) (ptr->arg);
if (ptr->free_arg)
(*ptr->free_arg) (ptr->arg);
xfree (ptr);
}
}
/* Discard final cleanups and do the actions they describe. */
void
do_final_cleanups ()
{
do_my_cleanups (&final_cleanup_chain, SENTINEL_CLEANUP);
}
|
