Update copyright dates
[src/app-framework-binder.git] / src / sig-monitor.c
index 7598250..b209dbf 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 "IoT.bzh"
+ * Copyright (C) 2015-2020 "IoT.bzh"
  * Author José Bollo <jose.bollo@iot.bzh>
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
 
 #define _GNU_SOURCE
 
+/*******************************************************************************
+*  sig-monitor is under the control of several compilation flags
+*******************************************************************************/
+
+/* controls whether to dump stack or not */
+#if !defined(WITH_SIG_MONITOR_DUMPSTACK)
+#  define WITH_SIG_MONITOR_DUMPSTACK 1
+#endif
+
+/* control whether to monitor signals */
+#if !defined(WITH_SIG_MONITOR_SIGNALS)
+#  define WITH_SIG_MONITOR_SIGNALS 1
+#endif
+
+/* controls whether to monitor calls */
+#if !defined(WITH_SIG_MONITOR_FOR_CALL)
+#  define WITH_SIG_MONITOR_FOR_CALL 1
+#endif
+
+/* control whether to monitor timers */
+#if !defined(WITH_SIG_MONITOR_TIMERS)
+#  define WITH_SIG_MONITOR_TIMERS 1
+#endif
+
+#if !WITH_SIG_MONITOR_SIGNALS
+#  undef WITH_SIG_MONITOR_FOR_CALL
+#  define WITH_SIG_MONITOR_FOR_CALL 0
+#endif
+
+#if !WITH_SIG_MONITOR_FOR_CALL
+#  undef WITH_SIG_MONITOR_TIMERS
+#  define WITH_SIG_MONITOR_TIMERS 0
+#endif
+
+/******************************************************************************/
+
 #include <stdlib.h>
 #include <stdio.h>
-#include <signal.h>
 #include <string.h>
-#include <setjmp.h>
-#include <time.h>
 #include <unistd.h>
-#include <sys/syscall.h>
-#include <execinfo.h>
 
 #include "sig-monitor.h"
+
 #include "verbose.h"
 
-#define SIG_FOR_TIMER   SIGVTALRM
+/******************************************************************************/
+#if !WITH_SIG_MONITOR_DUMPSTACK
 
-/* local handler */
-static _Thread_local sigjmp_buf *error_handler;
-static _Thread_local int in_safe_dumpstack;
+static inline void dumpstack(int crop, int signum) {}
 
-/* local timers */
-static _Thread_local int thread_timer_set;
-static _Thread_local timer_t thread_timerid;
+#else
+
+#include <execinfo.h>
 
 /*
  * Dumps the current stack
@@ -76,23 +107,28 @@ static void dumpstack(int crop, int signum)
        }
 }
 
-static void safe_dumpstack_cb(int signum, void *closure)
-{
-       int *args = closure;
-       if (signum)
-               ERROR("Can't provide backtrace: raised signal %s", strsignal(signum));
-       else
-               dumpstack(args[0], args[1]);
-}
+#endif
+/******************************************************************************/
+#if !WITH_SIG_MONITOR_TIMERS
 
-static void safe_dumpstack(int crop, int signum)
-{
-       int args[2] = { crop, signum };
+static inline int timeout_create() { return 0; }
+static inline int timeout_arm(int timeout) { return 0; }
+static inline void timeout_disarm() {}
+static inline void timeout_delete() {}
 
-       in_safe_dumpstack = 1;
-       sig_monitor(0, safe_dumpstack_cb, args);
-       in_safe_dumpstack = 0;
-}
+#define SIG_FOR_TIMER   0
+
+#else
+
+#include <time.h>
+#include <sys/syscall.h>
+#include <signal.h>
+
+#define SIG_FOR_TIMER   SIGVTALRM
+
+/* local per thread timers */
+static _Thread_local int thread_timer_set;
+static _Thread_local timer_t thread_timerid;
 
 /*
  * Creates a timer for the current thread
@@ -118,7 +154,7 @@ static inline int timeout_create()
                rc = timer_create(CLOCK_THREAD_CPUTIME_ID, &sevp, &thread_timerid);
                thread_timer_set = !rc;
        }
-       return 0;
+       return rc;
 }
 
 /*
@@ -160,43 +196,67 @@ static inline void timeout_delete()
                thread_timer_set = 0;
        }
 }
+#endif
+/******************************************************************************/
+#if !WITH_SIG_MONITOR_FOR_CALL
 
+static inline void monitor_raise(int signum) {}
 
-/* Handles signals that terminate the process */
-static void on_signal_terminate (int signum)
+#else
+
+#include <setjmp.h>
+
+/* local handler */
+static _Thread_local sigjmp_buf *error_handler;
+
+static void monitor(int timeout, void (*function)(int sig, void*), void *arg)
 {
-       if (!in_safe_dumpstack) {
-               ERROR("Terminating signal %d received: %s", signum, strsignal(signum));
-               if (signum == SIGABRT)
-                       safe_dumpstack(3, signum);
+       volatile int signum, signum2;
+       sigjmp_buf jmpbuf, *older;
+
+       older = error_handler;
+       signum = setjmp(jmpbuf);
+       if (signum == 0) {
+               error_handler = &jmpbuf;
+               if (timeout) {
+                       timeout_create();
+                       timeout_arm(timeout);
+               }
+               function(0, arg);
+       } else {
+               signum2 = setjmp(jmpbuf);
+               if (signum2 == 0)
+                       function(signum, arg);
        }
-       exit(1);
+       if (timeout)
+               timeout_disarm();
+       error_handler = older;
 }
 
-/* Handles monitored signals that can be continued */
-static void on_signal_error(int signum)
+static inline void monitor_raise(int signum)
 {
-       sigset_t sigset;
-
-       if (in_safe_dumpstack)
+       if (error_handler != NULL)
                longjmp(*error_handler, signum);
+}
+#endif
+/******************************************************************************/
+#if !WITH_SIG_MONITOR_SIGNALS
 
-       ERROR("ALERT! signal %d received: %s", signum, strsignal(signum));
-       if (error_handler == NULL && signum == SIG_FOR_TIMER)
-               return;
+static inline int enable_signal_handling() { return 0; }
 
-       safe_dumpstack(3, signum);
+#else
 
-       // unlock signal to allow a new signal to come
-       if (error_handler != NULL)
-               longjmp(*error_handler, signum);
+#include <signal.h>
 
-       ERROR("Unmonitored signal %d received: %s", signum, strsignal(signum));
-       exit(2);
-}
+/* internal signal lists */
+static int sigerr[] = { SIGSEGV, SIGFPE, SIGILL, SIGBUS, SIG_FOR_TIMER, 0 };
+static int sigterm[] = { SIGINT, SIGABRT, SIGTERM, 0 };
+
+static int exiting = 0;
+static int enabled = 0;
 
 /* install the handlers */
-static int install(void (*handler)(int), int *signals)
+static int set_signals_handler(void (*handler)(int), int *signals)
 {
        int result = 1;
        struct sigaction sa;
@@ -214,12 +274,127 @@ static int install(void (*handler)(int), int *signals)
        return result;
 }
 
-int sig_monitor_init()
+/*
+ * rescue exit
+ */
+static void on_rescue_exit(int signum)
 {
-       static int sigerr[] = { SIG_FOR_TIMER, SIGSEGV, SIGFPE, SIGILL, SIGBUS, 0 };
-       static int sigterm[] = { SIGINT, SIGABRT, SIGTERM, 0 };
+       ERROR("Rescue exit for signal %d: %s", signum, strsignal(signum));
+       _exit(exiting);
+}
 
-       return (install(on_signal_error, sigerr) & install(on_signal_terminate, sigterm)) - 1;
+/*
+ * Do a direct safe exit
+ */
+static void direct_safe_exit(int code)
+{
+       set_signals_handler(on_rescue_exit, sigerr);
+       set_signals_handler(on_rescue_exit, sigterm);
+       exiting = code;
+       exit(code);
+}
+
+/*
+ * Do a safe exit
+ */
+#if WITH_SIG_MONITOR_NO_DEFERRED_EXIT
+#  define safe_exit(x) direct_safe_exit(x)
+#else
+#include "jobs.h"
+static void exit_job(int signum, void* arg)
+{
+       exiting = (int)(intptr_t)arg;
+       if (signum)
+               on_rescue_exit(signum);
+       exit(exiting);
+}
+
+static void safe_exit(int code)
+{
+       if (jobs_queue(safe_exit, 0, exit_job, (void*)(intptr_t)code))
+               direct_safe_exit(code);
+}
+#endif
+
+#if !WITH_SIG_MONITOR_DUMPSTACK
+
+static inline void safe_dumpstack(int crop, int signum) {}
+#define in_safe_dumpstack (0)
+
+#else
+
+static _Thread_local int in_safe_dumpstack;
+
+static void safe_dumpstack_cb(int signum, void *closure)
+{
+       int *args = closure;
+       if (signum)
+               ERROR("Can't provide backtrace: raised signal %s", strsignal(signum));
+       else
+               dumpstack(args[0], args[1]);
+}
+
+static void safe_dumpstack(int crop, int signum)
+{
+       int args[2] = { crop + 3, signum };
+
+       in_safe_dumpstack = 1;
+       sig_monitor(0, safe_dumpstack_cb, args);
+       in_safe_dumpstack = 0;
+}
+#endif
+
+/* Handles signals that terminate the process */
+static void on_signal_terminate (int signum)
+{
+       if (!in_safe_dumpstack) {
+               ERROR("Terminating signal %d received: %s", signum, strsignal(signum));
+               if (signum == SIGABRT)
+                       safe_dumpstack(3, signum);
+       }
+       safe_exit(1);
+}
+
+/* Handles monitored signals that can be continued */
+static void on_signal_error(int signum)
+{
+       if (!in_safe_dumpstack) {
+               ERROR("ALERT! signal %d received: %s", signum, strsignal(signum));
+
+               safe_dumpstack(3, signum);
+       }
+       monitor_raise(signum);
+
+       if (signum != SIG_FOR_TIMER) {
+               ERROR("Unmonitored signal %d received: %s", signum, strsignal(signum));
+               safe_exit(2);
+       }
+}
+
+/*
+static void disable_signal_handling()
+{
+       set_signals_handler(SIG_DFL, sigerr);
+       set_signals_handler(SIG_DFL, sigterm);
+       enabled = 0;
+}
+*/
+
+static int enable_signal_handling()
+{
+       if (!set_signals_handler(on_signal_error, sigerr)
+            || !set_signals_handler(on_signal_terminate, sigterm)) {
+               return -1;
+       }
+       enabled = 1;
+       return 0;
+}
+#endif
+/******************************************************************************/
+
+int sig_monitor_init(int enable)
+{
+       return enable ? enable_signal_handling() : 0;
 }
 
 int sig_monitor_init_timeouts()
@@ -234,24 +409,15 @@ void sig_monitor_clean_timeouts()
 
 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);
+#if WITH_SIG_MONITOR_SIGNALS && WITH_SIG_MONITOR_FOR_CALL
+       if (enabled)
+               monitor(timeout, function, arg);
+       else
+#endif
                function(0, arg);
-       } else {
-               signum2 = setjmp(jmpbuf);
-               if (signum2 == 0)
-                       function(signum, arg);
-       }
-       error_handler = older;
-       if (timeout)
-               timeout_disarm();
 }
 
-
+void sig_monitor_dumpstack()
+{
+       return dumpstack(1, 0);
+}