#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include <string.h>
#ifndef getSigName
#define getSigName(sig) (((sig) == SIGCHLD)?"SIGCHLD":(((sig) == SIGCONT)?"SIGCONT":(((sig) == SIGTERM)?"SIGTERM":(((sig) == SIGWINCH)?"SIGWINCH":""))))
#endif
static void printTime() {
    time_t calendar_time = time(NULL);
    struct tm * tm_local = localtime(&calendar_time);
    char str_f_t [50];
    strftime(str_f_t, sizeof(str_f_t), "%G-%m-%d %H:%M:%S", tm_local);
    printf("%s ", str_f_t);
}
static void handleSignal(int sig) {
    printTime();
    printf("PID=%d handleSignal %s=%d\n", getpid(), getSigName(sig), sig);
    if (sig == SIGCHLD || sig == SIGTERM) {
        // 子进程被暂停或退出了(包括按逻辑执行结束及被kill)
        int status = 0;
        int childPid = waitpid(-1, &status, WUNTRACED|WCONTINUED);
        if (childPid == -1) {
            printTime();
            printf("Parent w=-1, error=%s \n", strerror(errno));
        } else {
            int ifExited, ifSignaled, ifStopped, ifContinued;
            
            ifExited = WIFEXITED(status);
            ifSignaled = WIFSIGNALED(status);
            ifStopped = WIFSTOPPED(status);
            ifContinued = WIFCONTINUED(status);
            
            printTime();
            printf("pid=%ld child=%d exitCode=%d status=%d ifExited=%d ifSignaled=%d ifStopped=%d ifContinued=%d \n",
                   (long)getpid(), childPid, status, _WSTATUS(childPid), ifExited, ifSignaled, ifStopped, ifContinued);
            
            printTime();
            if (ifExited) {
                printf("PID=%ld exited, status=%d\n", (long)childPid, WEXITSTATUS(status));
            } else if (ifSignaled) {
                printf("PID=%ld killed by signal %d\n", (long)childPid, WTERMSIG(status));
            } else if (ifStopped) {
                printf("PID=%ld stopped by signal %d\n", (long)childPid, WSTOPSIG(status));
            } else if (ifContinued) {
                printf("PID=%ld continued\n", (long)childPid);
            }
        }
    } else if (sig == SIGCONT) {
        // sigcont在本人的mac上调用wait是无效的
        // do nothing
    } else if (sig == SIGWINCH) {
        // do nothing
    } else {
        printTime();
        printf("sig=%d is not valid.\n", sig);
    }
}
static void mainProcessDoSomething(FILE* f) {
    int count = 0;
    while(1) {
        sleep(3);
        if (f != NULL){
            fflush(f);
        }
        if (count ++ > 50) {
            break;
        }
    }
}
int main/*11*/ (int argc, char ** argv) {
    
    // SIGWINCH：应用程序窗口发生变化
    signal(SIGWINCH, &handleSignal);
    
    // 子进程被暂停运行
    signal(SIGSTOP, &handleSignal);
    // 子进程被恢复运行(Mac上无效..)
    signal(SIGCONT, &handleSignal);
    // SIGCHLD：子进程被暂停或退出了(包括按逻辑执行结束及被kill)
    signal(SIGCHLD, &handleSignal);
    // 不建议对SIGTERM进行设置
    // signal(SIGTERM, &handleSignal);
    
    pid_t pId = fork();
    if (pId == -1) {
        perror("fork error");
        exit(EXIT_FAILURE);
    } else if (pId == 0) {
        FILE* fChild = freopen("/Users/sodino/workspace/xcode/Define/Define/child_signal.txt", "w", stdout);
        int myPid = getpid();
        int parentPid = getppid();
        
        printTime();
        printf("Child:SelfID=%d ParentID=%d \n", myPid, parentPid);
        int count = 0;
        do{
            count ++;
            sleep(5);
            printTime();
            printf("Child:count=%d \n", count);
            fflush(fChild);
            if (count >= 20) {
                break;
            }
        }while (1);
        printTime();
        printf("Child:SelfID=%d exit success.\n", myPid);
        fflush(fChild);
        fclose(fChild);
        return EXIT_SUCCESS;
    } else {
        FILE * fMain = freopen("/Users/sodino/workspace/xcode/Define/Define/main_signal.txt", "w", stdout);
        printTime();
        printf("Parent:SelfID=%d MyChildPID=%d \n", getpid(), pId);
        fflush(fMain);
        
        // 继续往下执行其它任务，而不像原逻辑 会被wait()所阻塞
        mainProcessDoSomething(fMain);
        
        printTime();
        printf("Parent:SelfID=%d exit success.\n", getpid());
        
        fflush(fMain);
        fclose(fMain);
        return EXIT_SUCCESS;
    }
}