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
|
/*
* Copyright (C) 2017 "IoT.bzh"
* Author José Bollo <jose.bollo@iot.bzh>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define _GNU_SOURCE
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <setjmp.h>
#include <time.h>
#include <unistd.h>
#include <sys/syscall.h>
#include "sig-monitor.h"
#include "verbose.h"
#define SIG_FOR_TIMER (SIGVTALRM+2)
/* local handler */
static _Thread_local sigjmp_buf *error_handler;
/* local timers */
static _Thread_local int thread_timer_set;
static _Thread_local timer_t thread_timerid;
/*
* Creates a timer for the current thread
*
* Returns 0 in case of success
*/
static inline int timeout_create()
{
int rc;
struct sigevent sevp;
if (thread_timer_set)
rc = 0;
else {
sevp.sigev_notify = SIGEV_THREAD_ID;
sevp.sigev_signo = SIG_FOR_TIMER;
sevp.sigev_value.sival_ptr = NULL;
#if defined(sigev_notify_thread_id)
sevp.sigev_notify_thread_id = (pid_t)syscall(SYS_gettid);
#else
sevp._sigev_un._tid = (pid_t)syscall(SYS_gettid);
#endif
rc = timer_create(CLOCK_THREAD_CPUTIME_ID, &sevp, &thread_timerid);
thread_timer_set = !rc;
}
return 0;
}
/*
* Arms the alarm in timeout seconds for the current thread
*/
static inline int timeout_arm(int timeout)
{
int rc;
struct itimerspec its;
rc = timeout_create();
if (rc == 0) {
its.it_interval.tv_sec = 0;
its.it_interval.tv_nsec = 0;
its.it_value.tv_sec = timeout;
its.it_value.tv_nsec = 0;
rc = timer_settime(thread_timerid, 0, &its, NULL);
}
return rc;
}
/*
* Disarms the current alarm
*/
static inline void timeout_disarm()
{
if (thread_timer_set)
timeout_arm(0);
}
/*
* Destroy any alarm resource for the current thread
*/
static inline void timeout_delete()
{
if (thread_timer_set) {
timer_delete(thread_timerid);
thread_timer_set = 0;
}
}
/* Handles signals that terminate the process */
static void on_signal_terminate (int signum)
{
ERROR("Terminating signal %d received: %s", signum, strsignal(signum));
exit(1);
}
/* Handles monitored signals that can be continued */
static void on_signal_error(int signum)
{
sigset_t sigset;
ERROR("ALERT! signal %d received: %s", signum, strsignal(signum));
// unlock signal to allow a new signal to come
if (error_handler != NULL) {
sigemptyset(&sigset);
sigaddset(&sigset, signum);
sigprocmask(SIG_UNBLOCK, &sigset, 0);
longjmp(*error_handler, signum);
}
if (signum == SIG_FOR_TIMER)
return;
ERROR("Unmonitored signal %d received: %s", signum, strsignal(signum));
exit(2);
}
/* install the handlers */
static int install(void (*handler)(int), int *signals)
{
int result = 1;
while(*signals > 0) {
if (signal(*signals, handler) == SIG_ERR) {
ERROR("failed to install signal handler for signal %s", strsignal(*signals));
result = 0;
}
signals++;
}
return result;
}
int sig_monitor_init()
{
static int sigerr[] = { SIG_FOR_TIMER, SIGSEGV, SIGFPE, 0 };
static int sigterm[] = { SIGINT, SIGABRT, 0 };
return (install(on_signal_error, sigerr) & install(on_signal_terminate, sigterm)) - 1;
}
int sig_monitor_init_timeouts()
{
return timeout_create();
}
void sig_monitor_clean_timeouts()
{
timeout_delete();
}
void sig_monitor(int timeout, void (*function)(int sig, void*), void *arg)
{
volatile int signum, signum2;
sigjmp_buf jmpbuf, *older;
older = error_handler;
signum = setjmp(jmpbuf);
if (signum == 0) {
error_handler = &jmpbuf;
if (timeout)
timeout_arm(timeout);
function(0, arg);
} else {
signum2 = setjmp(jmpbuf);
if (signum2 == 0)
function(signum, arg);
}
error_handler = older;
if (timeout)
timeout_disarm();
}
|