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signal_recovery.c
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signal_recovery.c
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/*
* Copyright (C) 2019 Wang Donghui
*
* 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.
*/
#include "signal_recovery.h"
#include <pthread.h>
#include <memory.h>
#include <stdlib.h>
static pthread_key_t env_key;
struct env_buf_t {
sigjmp_buf jmp_buf;
struct env_buf_t* next;
siginfo_t info;
};
env_buf_t* env_buf_alloc() {
return (env_buf_t*)calloc(1, sizeof(env_buf_t));
}
void env_buf_free(env_buf_t* env_buf) {
free(env_buf);
}
/**
* @return - current env_buf in current thread
*/
env_buf_t* env_buf_cur() {
return (env_buf_t*)pthread_getspecific(env_key);
}
sigjmp_buf* env_buf_get(env_buf_t* env_buf) {
return &env_buf->jmp_buf;
}
void env_buf_push(env_buf_t* env_buf) {
env_buf_t* top_item = env_buf_cur();
env_buf->next = top_item;
pthread_setspecific(env_key, env_buf);
}
void env_buf_pop() {
env_buf_t* top_item = env_buf_cur();
if (top_item != NULL) {
env_buf_t* next_item = top_item->next;
pthread_setspecific(env_key, next_item);
env_buf_free(top_item);
}
}
static pthread_once_t once = PTHREAD_ONCE_INIT;
#ifndef NSIG
#define NSIG 65
#endif
// Old signal action records
static struct sigaction old_sa[NSIG];
typedef struct signal_item {
int signo;
const char* name;
struct signal_item* next;
} signal_item;
static signal_item* entry;
static void add_signal_name(int signo, const char* signame) {
signal_item* item = (signal_item*)calloc(1, sizeof(signal_item));
item->signo = signo;
item->name = signame;
item->next = entry;
entry = item;
}
#define handle_signal(sig) \
add_signal_name(sig, #sig); \
sigaction(sig, &action_info, &old_sa[sig])
static void env_key_create() {
pthread_key_create(&env_key, NULL);
}
static void signal_handler(int signal, siginfo_t *info, void *reserved) {
env_buf_t* cur_env = env_buf_cur();
if (cur_env != NULL) {
cur_env->info = *info;
siglongjmp(cur_env->jmp_buf, SAVE_SIGNAL_MASK);
}
else {
struct sigaction* old_action = &old_sa[signal];
if (old_action->sa_flags & SA_SIGINFO) {
if (old_action->sa_sigaction != NULL) {
old_action->sa_sigaction(signal, info, reserved);
}
}
else {
if (old_action->sa_handler != NULL) {
old_action->sa_handler(signal);
}
}
}
}
static void signal_handler_init() {
struct sigaction action_info;
memset(&action_info, 0, sizeof(sigaction));
action_info.sa_sigaction = signal_handler;
action_info.sa_flags = SA_SIGINFO;
handle_signal(SIGSEGV); // Segmentation violation
handle_signal(SIGFPE); // Floating point exception
handle_signal(SIGILL); // Illegal instruction
handle_signal(SIGBUS); // Bus error
}
static void try_catch_init() {
env_key_create();
signal_handler_init();
}
void signal_catch_init() {
pthread_once(&once, try_catch_init);
}
siginfo_t* signal_info() {
env_buf_t* cur_env = env_buf_cur();
if (cur_env != NULL
&& 0 < cur_env->info.si_signo) {
return &cur_env->info;
}
return NULL;
}
const char* signal_name(int signo) {
signal_item* item = entry;
while (item != NULL) {
if (item->signo == signo) {
return item->name;
}
item = item->next;
}
return "Unknown signal";
}