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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
/* Linuxthreads - a simple clone()-based implementation of Posix */
/* threads for Linux. */
/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
/* */
/* This program is free software; you can redistribute it and/or */
/* modify it under the terms of the GNU Library 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 Library General Public License for more details. */
/* Handling of signals */
#include <errno.h>
#include <signal.h>
#include "pthread.h"
#include "internals.h"
#include "spinlock.h"
#include <ucontext.h>
int pthread_sigmask(int how, const sigset_t * newmask, sigset_t * oldmask)
{
sigset_t mask;
if (newmask != NULL) {
mask = *newmask;
/* Don't allow __pthread_sig_restart to be unmasked.
Don't allow __pthread_sig_cancel to be masked. */
switch(how) {
case SIG_SETMASK:
sigaddset(&mask, __pthread_sig_restart);
sigdelset(&mask, __pthread_sig_cancel);
break;
case SIG_BLOCK:
sigdelset(&mask, __pthread_sig_cancel);
break;
case SIG_UNBLOCK:
sigdelset(&mask, __pthread_sig_restart);
break;
}
newmask = &mask;
}
if (sigprocmask(how, newmask, oldmask) == -1)
return errno;
else
return 0;
}
int pthread_kill(pthread_t thread, int signo)
{
pthread_handle handle = thread_handle(thread);
int pid;
__pthread_lock(&handle->h_lock, NULL);
if (invalid_handle(handle, thread)) {
__pthread_unlock(&handle->h_lock);
return ESRCH;
}
pid = handle->h_descr->p_pid;
__pthread_unlock(&handle->h_lock);
if (kill(pid, signo) == -1)
return errno;
else
return 0;
}
union sighandler __sighandler[NSIG] =
{ [1 ... NSIG - 1] = { (arch_sighandler_t) SIG_ERR } };
/* The wrapper around sigaction. Install our own signal handler
around the signal. */
int __pthread_sigaction(int sig, const struct sigaction * act,
struct sigaction * oact)
{
struct sigaction newact;
struct sigaction *newactp;
__sighandler_t old = SIG_DFL;
if (sig == __pthread_sig_restart ||
sig == __pthread_sig_cancel ||
(sig == __pthread_sig_debug && __pthread_sig_debug > 0))
{
__set_errno (EINVAL);
return -1;
}
if (sig > 0 && sig < NSIG)
old = (__sighandler_t) __sighandler[sig].old;
if (act)
{
newact = *act;
if (act->sa_handler != SIG_IGN && act->sa_handler != SIG_DFL
&& sig > 0 && sig < NSIG)
{
if (act->sa_flags & SA_SIGINFO)
newact.sa_handler = (__sighandler_t) __pthread_sighandler_rt;
else
newact.sa_handler = (__sighandler_t) __pthread_sighandler;
if (old == SIG_IGN || old == SIG_DFL || old == SIG_ERR)
__sighandler[sig].old = (arch_sighandler_t) act->sa_handler;
}
newactp = &newact;
}
else
newactp = NULL;
if (__libc_sigaction(sig, newactp, oact) == -1)
{
if (act)
__sighandler[sig].old = (arch_sighandler_t) old;
return -1;
}
if (sig > 0 && sig < NSIG)
{
if (oact != NULL
/* We may have inherited SIG_IGN from the parent, so return the
kernel's idea of the signal handler the first time
through. */
&& old != SIG_ERR)
oact->sa_handler = old;
if (act)
/* For the assignment it does not matter whether it's a normal
or real-time signal. */
__sighandler[sig].old = (arch_sighandler_t) act->sa_handler;
}
return 0;
}
#ifdef SHARED
strong_alias(__pthread_sigaction, __sigaction)
strong_alias(__pthread_sigaction, sigaction)
#endif
/* sigwait -- synchronously wait for a signal */
int __pthread_sigwait(const sigset_t * set, int * sig)
{
volatile pthread_descr self = thread_self();
sigset_t mask;
int s;
sigjmp_buf jmpbuf;
struct sigaction sa;
/* Get ready to block all signals except those in set
and the cancellation signal.
Also check that handlers are installed on all signals in set,
and if not, install our dummy handler. This is conformant to
POSIX: "The effect of sigwait() on the signal actions for the
signals in set is unspecified." */
sigfillset(&mask);
sigdelset(&mask, __pthread_sig_cancel);
for (s = 1; s < NSIG; s++) {
if (sigismember(set, s) &&
s != __pthread_sig_restart &&
s != __pthread_sig_cancel &&
s != __pthread_sig_debug) {
sigdelset(&mask, s);
if (__sighandler[s].old == (arch_sighandler_t) SIG_ERR ||
__sighandler[s].old == (arch_sighandler_t) SIG_DFL ||
__sighandler[s].old == (arch_sighandler_t) SIG_IGN) {
sa.sa_handler = __pthread_null_sighandler;
sigfillset(&sa.sa_mask);
sa.sa_flags = 0;
sigaction(s, &sa, NULL);
}
}
}
/* Test for cancellation */
if (sigsetjmp(jmpbuf, 1) == 0) {
THREAD_SETMEM(self, p_cancel_jmp, &jmpbuf);
if (! (THREAD_GETMEM(self, p_canceled)
&& THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE)) {
/* Reset the signal count */
THREAD_SETMEM(self, p_signal, 0);
/* Say we're in sigwait */
THREAD_SETMEM(self, p_sigwaiting, 1);
/* Unblock the signals and wait for them */
sigsuspend(&mask);
}
}
THREAD_SETMEM(self, p_cancel_jmp, NULL);
/* The signals are now reblocked. Check for cancellation */
pthread_testcancel();
/* We should have self->p_signal != 0 and equal to the signal received */
*sig = THREAD_GETMEM(self, p_signal);
return 0;
}
#ifdef SHARED
strong_alias (__pthread_sigwait, sigwait)
#endif
/* Redefine raise() to send signal to calling thread only,
as per POSIX 1003.1c */
int __pthread_raise (int sig)
{
int retcode = pthread_kill(pthread_self(), sig);
if (retcode == 0)
return 0;
else {
errno = retcode;
return -1;
}
}
#ifdef SHARED
strong_alias (__pthread_raise, raise)
#endif
/* This files handles cancellation internally. */
LIBC_CANCEL_HANDLED ();
|
