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
|
/* Convenience function to catch expected signals during an operation.
Copyright (C) 1996-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <hurd/signal.h>
#include <hurd/sigpreempt.h>
#include <string.h>
#include <assert.h>
error_t
__hurd_catch_signal (sigset_t sigset,
unsigned long int first, unsigned long int last,
error_t (*operate) (struct hurd_signal_preemptor *),
sighandler_t handler)
{
/* We need to restore the signal mask, because otherwise the
signal-handling code will have blocked the caught signal and for
instance calling hurd_catch_signal again would then dump core. */
sigjmp_buf buf;
void throw (int signo, long int sigcode, struct sigcontext *scp)
{ siglongjmp (buf, scp->sc_error ?: EGRATUITOUS); }
struct hurd_signal_preemptor preemptor =
{
sigset, first, last,
NULL, handler == SIG_ERR ? (sighandler_t) &throw : handler,
};
struct hurd_sigstate *const ss = _hurd_self_sigstate ();
error_t error;
if (handler != SIG_ERR)
/* Not our handler; don't bother saving state. */
error = 0;
else
/* This returns again with nonzero value when we preempt a signal. */
error = sigsetjmp (buf, 1);
if (error == 0)
{
/* Install a signal preemptor for the thread. */
__spin_lock (&ss->lock);
preemptor.next = ss->preemptors;
ss->preemptors = &preemptor;
__spin_unlock (&ss->lock);
/* Try the operation that might crash. */
(*operate) (&preemptor);
}
/* Either FUNCTION completed happily and ERROR is still zero, or it hit
an expected signal and `throw' made setjmp return the signal error
code in ERROR. Now we can remove the preemptor and return. */
__spin_lock (&ss->lock);
assert (ss->preemptors == &preemptor);
ss->preemptors = preemptor.next;
__spin_unlock (&ss->lock);
return error;
}
strong_alias (__hurd_catch_signal, hurd_catch_signal)
error_t
hurd_safe_memset (void *dest, int byte, size_t nbytes)
{
error_t operate (struct hurd_signal_preemptor *preemptor)
{
memset (dest, byte, nbytes);
return 0;
}
return __hurd_catch_signal (__sigmask (SIGBUS) | __sigmask (SIGSEGV),
(vm_address_t) dest, (vm_address_t) dest + nbytes,
&operate, SIG_ERR);
}
error_t
hurd_safe_copyout (void *dest, const void *src, size_t nbytes)
{
error_t operate (struct hurd_signal_preemptor *preemptor)
{
memcpy (dest, src, nbytes);
return 0;
}
return __hurd_catch_signal (__sigmask (SIGBUS) | __sigmask (SIGSEGV),
(vm_address_t) dest, (vm_address_t) dest + nbytes,
&operate, SIG_ERR);
}
error_t
hurd_safe_copyin (void *dest, const void *src, size_t nbytes)
{
error_t operate (struct hurd_signal_preemptor *preemptor)
{
memcpy (dest, src, nbytes);
return 0;
}
return __hurd_catch_signal (__sigmask (SIGBUS) | __sigmask (SIGSEGV),
(vm_address_t) src, (vm_address_t) src + nbytes,
&operate, SIG_ERR);
}
error_t
hurd_safe_memmove (void *dest, const void *src, size_t nbytes)
{
jmp_buf buf;
void throw (int signo, long int sigcode, struct sigcontext *scp)
{ longjmp (buf, scp->sc_error ?: EGRATUITOUS); }
struct hurd_signal_preemptor src_preemptor =
{
__sigmask (SIGBUS) | __sigmask (SIGSEGV),
(vm_address_t) src, (vm_address_t) src + nbytes,
NULL, (sighandler_t) &throw,
};
struct hurd_signal_preemptor dest_preemptor =
{
__sigmask (SIGBUS) | __sigmask (SIGSEGV),
(vm_address_t) dest, (vm_address_t) dest + nbytes,
NULL, (sighandler_t) &throw,
&src_preemptor
};
struct hurd_sigstate *const ss = _hurd_self_sigstate ();
error_t error;
/* This returns again with nonzero value when we preempt a signal. */
error = setjmp (buf);
if (error == 0)
{
/* Install a signal preemptor for the thread. */
__spin_lock (&ss->lock);
src_preemptor.next = ss->preemptors;
ss->preemptors = &dest_preemptor;
__spin_unlock (&ss->lock);
/* Do the copy; it might fault. */
memmove (dest, src, nbytes);
}
/* Either memmove completed happily and ERROR is still zero, or it hit
an expected signal and `throw' made setjmp return the signal error
code in ERROR. Now we can remove the preemptor and return. */
__spin_lock (&ss->lock);
assert (ss->preemptors == &dest_preemptor);
ss->preemptors = src_preemptor.next;
__spin_unlock (&ss->lock);
return error;
}
|
