2 * Copyright (C) 2017 "IoT.bzh"
3 * Author José Bollo <jose.bollo@iot.bzh>
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
27 #include <sys/syscall.h>
30 #include "sig-monitor.h"
33 #define SIG_FOR_TIMER SIGVTALRM
36 static _Thread_local sigjmp_buf *error_handler;
39 static _Thread_local int thread_timer_set;
40 static _Thread_local timer_t thread_timerid;
43 * Dumps the current stack
45 static void dumpstack(int crop, int signum)
53 count = backtrace(addresses, sizeof addresses / sizeof *addresses);
57 locations = backtrace_symbols(&addresses[crop], count);
58 if (locations == NULL)
59 ERROR("can't get the backtrace (returned %d addresses)", count);
61 length = sizeof buffer - 1;
64 while (pos < length && idx < count) {
65 rc = snprintf(&buffer[pos], length - pos, " [%d/%d] %s\n", idx + 1, count, locations[idx]);
66 pos += rc >= 0 ? rc : 0;
71 ERROR("BACKTRACE due to signal %s/%d:\n%s", strsignal(signum), signum, buffer);
73 ERROR("BACKTRACE:\n%s", buffer);
79 * Creates a timer for the current thread
81 * Returns 0 in case of success
83 static inline int timeout_create()
91 sevp.sigev_notify = SIGEV_THREAD_ID;
92 sevp.sigev_signo = SIG_FOR_TIMER;
93 sevp.sigev_value.sival_ptr = NULL;
94 #if defined(sigev_notify_thread_id)
95 sevp.sigev_notify_thread_id = (pid_t)syscall(SYS_gettid);
97 sevp._sigev_un._tid = (pid_t)syscall(SYS_gettid);
99 rc = timer_create(CLOCK_THREAD_CPUTIME_ID, &sevp, &thread_timerid);
100 thread_timer_set = !rc;
106 * Arms the alarm in timeout seconds for the current thread
108 static inline int timeout_arm(int timeout)
111 struct itimerspec its;
113 rc = timeout_create();
115 its.it_interval.tv_sec = 0;
116 its.it_interval.tv_nsec = 0;
117 its.it_value.tv_sec = timeout;
118 its.it_value.tv_nsec = 0;
119 rc = timer_settime(thread_timerid, 0, &its, NULL);
126 * Disarms the current alarm
128 static inline void timeout_disarm()
130 if (thread_timer_set)
135 * Destroy any alarm resource for the current thread
137 static inline void timeout_delete()
139 if (thread_timer_set) {
140 timer_delete(thread_timerid);
141 thread_timer_set = 0;
146 /* Handles signals that terminate the process */
147 static void on_signal_terminate (int signum)
149 ERROR("Terminating signal %d received: %s", signum, strsignal(signum));
150 if (signum == SIGABRT)
151 dumpstack(3, signum);
155 /* Handles monitored signals that can be continued */
156 static void on_signal_error(int signum)
160 ERROR("ALERT! signal %d received: %s", signum, strsignal(signum));
161 if (error_handler == NULL && signum == SIG_FOR_TIMER)
164 dumpstack(3, signum);
166 // unlock signal to allow a new signal to come
167 if (error_handler != NULL) {
168 sigemptyset(&sigset);
169 sigaddset(&sigset, signum);
170 sigprocmask(SIG_UNBLOCK, &sigset, 0);
171 longjmp(*error_handler, signum);
173 ERROR("Unmonitored signal %d received: %s", signum, strsignal(signum));
177 /* install the handlers */
178 static int install(void (*handler)(int), int *signals)
181 while(*signals > 0) {
182 if (signal(*signals, handler) == SIG_ERR) {
183 ERROR("failed to install signal handler for signal %s", strsignal(*signals));
191 int sig_monitor_init()
193 static int sigerr[] = { SIG_FOR_TIMER, SIGSEGV, SIGFPE, SIGILL, SIGBUS, 0 };
194 static int sigterm[] = { SIGINT, SIGABRT, SIGTERM, 0 };
196 return (install(on_signal_error, sigerr) & install(on_signal_terminate, sigterm)) - 1;
199 int sig_monitor_init_timeouts()
201 return timeout_create();
204 void sig_monitor_clean_timeouts()
209 void sig_monitor(int timeout, void (*function)(int sig, void*), void *arg)
211 volatile int signum, signum2;
212 sigjmp_buf jmpbuf, *older;
214 older = error_handler;
215 signum = setjmp(jmpbuf);
217 error_handler = &jmpbuf;
219 timeout_arm(timeout);
222 signum2 = setjmp(jmpbuf);
224 function(signum, arg);
226 error_handler = older;