int do_exit(long code)
{
int i;
free_page_tables(get_base(current->ldt[1]),get_limit(0x0f));
free_page_tables(get_base(current->ldt[2]),get_limit(0x17));
for (i=0 ; i<NR_TASKS ; i++)
if (task[i] && task[i]->father == current->pid) {
task[i]->father = 1;
if (task[i]->state == TASK_ZOMBIE)
/* assumption task[1] is always init */
(void) send_sig(SIGCHLD, task[1], 1);
}
for (i=0 ; i<NR_OPEN ; i++)
if (current->filp[i])
sys_close(i);
iput(current->pwd);
current->pwd=NULL;
iput(current->root);
current->root=NULL;
iput(current->executable);
current->executable=NULL;
if (current->leader && current->tty >= 0)
tty_table[current->tty].pgrp = 0;
if (last_task_used_math == current)
last_task_used_math = NULL;
if (current->leader)
kill_session();
current->state = TASK_ZOMBIE;
current->exit_code = code;
tell_father(current->father);
schedule();
return (-1); /* just to suppress warnings */
}
int do_exit(long code)
{
int i;
// TODO 待看页表
free_page_tables(get_base(current->ldt[1]),get_limit(0x0f));
free_page_tables(get_base(current->ldt[2]),get_limit(0x17));
/*
* 找出所有子进程，将它们的父亲设为 init 进程，将状态标记为僵尸
* 然后给 init 进程发送一个 SIGCHLD 信号，提醒 init 进程回收子进程
*/
for (i=0 ; i<NR_TASKS ; i++)
if (task[i] && task[i]->father == current->pid) {
task[i]->father = 1;
if (task[i]->state == TASK_ZOMBIE)
/* assumption task[1] is always init */
// 最后一个参数 1 代表 privilege，此处为强制发送
(void) send_sig(SIGCHLD, task[1], 1);
}
// TODO 关闭文件？
/*
* NR_OPEN 是一个进程可以打开的最大文件数
* 而 NR_FILE 是系统在某时刻的限制文件总数
*/
for (i=0 ; i<NR_OPEN ; i++)
if (current->filp[i])
sys_close(i);
// 进程的当前工作目录 inode
iput(current->pwd);
current->pwd=NULL;
// 进程的根目录 inode
iput(current->root);
current->root=NULL;
// 进程本身可执行文件的 inode
iput(current->executable);
current->executable=NULL;
if (current->leader && current->tty >= 0)
tty_table[current->tty].pgrp = 0;
if (last_task_used_math == current)
last_task_used_math = NULL;
/*
* 如果是 session leader 会话领头进程，则向该会话所有进程发送 SIGHUP 信号
* PID, PPID, PGID, SID
* http://unix.stackexchange.com/questions/18166/what-are-session-leaders-in-ps
* 在同一次 ssh 会话中，用户对应的 shell 最先被启动，成为 session leader，
* 所有在同一次会话中产生的进程 session id 都等于这个 session leader 的 pid
* 当 session leader 退出时，它会向所有同一 session 中的进程发送 SIGHUP，
* 这个信号是可以被捕获的，如果进程忽略这个 SIGHUP，它则可以以一个孤儿进程继续执行
* http://www.firefoxbug.com/index.php/archives/2782/
*/
if (current->leader)
kill_session();
// 将自己设为僵尸，设置退出状态码，同时告诉父进程回收子进程
current->state = TASK_ZOMBIE;
current->exit_code = code;
tell_father(current->father);
// 如果 tell_father 中找不到父进程，自己把自己释放掉了，那也不会有机会继续执行下面代码了
schedule();
return (-1); /* just to suppress warnings */
}
//// 程序退出处理程序。在系统调用的中断处理程序中被调用。
int
do_exit (long code) // code 是错误码。
{
int i;
// 释放当前进程代码段和数据段所占的内存页(free_page_tables()在mm/memory.c,105 行)。
free_page_tables (get_base (current->ldt[1]), get_limit (0x0f));
free_page_tables (get_base (current->ldt[2]), get_limit (0x17));
// 如果当前进程有子进程，就将子进程的father 置为1(其父进程改为进程1)。如果该子进程已经
// 处于僵死(ZOMBIE)状态，则向进程1 发送子进程终止信号SIGCHLD。
for (i = 0; i < NR_TASKS; i++)
if (task[i] && task[i]->father == current->pid)
{
task[i]->father = 1;
if (task[i]->state == TASK_ZOMBIE)
/* assumption task[1] is always init */
(void) send_sig (SIGCHLD, task[1], 1);
}
// 关闭当前进程打开着的所有文件。
for (i = 0; i < NR_OPEN; i++)
if (current->filp[i])
sys_close (i);
// 对当前进程工作目录pwd、根目录root 以及运行程序的i 节点进行同步操作，并分别置空。
iput (current->pwd);
current->pwd = NULL;
iput (current->root);
current->root = NULL;
iput (current->executable);
current->executable = NULL;
// 如果当前进程是领头(leader)进程并且其有控制的终端，则释放该终端。
if (current->leader && current->tty >= 0)
tty_table[current->tty].pgrp = 0;
// 如果当前进程上次使用过协处理器，则将last_task_used_math 置空。
if (last_task_used_math == current)
last_task_used_math = NULL;
// 如果当前进程是leader 进程，则终止所有相关进程。
if (current->leader)
kill_session ();
// 把当前进程置为僵死状态，并设置退出码。
current->state = TASK_ZOMBIE;
current->exit_code = code;
// 通知父进程，也即向父进程发送信号SIGCHLD -- 子进程将停止或终止。
tell_father (current->father);
schedule (); // 重新调度进程的运行。
return (-1); /* just to suppress warnings */
}
int do_exit()
{
int i;
struct task_struct *p = current;
int pid = p->pid;
printk("%d\n",pid);
for(i = 0;i < NR_PROCESS + NR_PROCS;i++)
{
if(proc_table[i].parent == pid)
{
proc_table[i].parent = 1; //init pid
if(proc_table[i].state == TASK_WAITING && proc_table[i].state == TASK_ZOMBIE)
{
// release_process(&proc_table[i]);
}
}
}
p->state = TASK_ZOMBIE;
// p->exit_code = code;
tell_father(p->parent);
schedule();
return 0;
}
int main(int argc, char const *argv[])
{
char buf[MAXSIZE]={'\0'};
char buf_r[MAXSIZE]={'\0'};
int fd[2];
pipe(fd);
signal(SIGPIPE,fun);
pid_t pid;
int len = 0;
int nr = 0;
int sum = 0;
int nread,len_r;
//signal tongbu
tell_wait();
//sgnal tongbu
pid = fork();
if (pid <0) {
perror("error");
/* code */
}else if (pid == 0) {
/* code */
wait_father();
printf("the child process.....%d\n",getpid());
printf("the child process's father process id:%d\n",getppid());
close(fd[1]);
while((nread = read(fd[0],buf,sizeof(buf)))!=-1){
tell_father(pid);
setbuf(stdout,NULL);//set the stdout no buffer
printf("the child write to stdout:");
write(STDOUT_FILENO,buf,nread); //the write to stdout is bo bug ,but the printf is bug
len_r = strlen(buf);
printf("len_r :%d\n",len_r );
for (int i = 0; (buf[i]!='\n'); i++) {
sum +=i;
printf("sum:%d\n",sum );
printf("buf[%d]:%c\t",i,buf[i] );
if (buf[i]=='\0') {
break;
}
}
printf("\n");
// printf("child read:%s\n",buf ); //the sentence is bug ,it is of buffer and \n
}
exit(0);
}else{
// sleep(3);
tell_child(pid);
printf("the father process.......%d\n",getpid());
printf("the father process's father process id:%d\n",getppid());
close(fd[0]);//the sentense to invlole the SIGPIPE take place
char * p = NULL; /* code */
while((p = fgets(buf,sizeof(buf),stdin))!=NULL){
len = strlen(buf);
printf("the length :%d\n",len );
if (p[len] =='\n') {
printf("%c\n",p[len -1] );
len--;
p[len ] = '\0';
/* code */
}
if (p[len -1] == '\0') {
printf("fgets read the null in buffer\n");
/* code */
}
fflush(stdin);
int n = write(fd[1],buf,len);
if (n==-1) {
if (errno = EINTR) {
printf("the failed is SIGINT\n");
/* code */
}
printf("err write\n");
}else
printf("father write to pipe successfully\n");
wait_child();
}
int status;
// the waitpid 's return val is the son process pid,if it wait to catch the son state successfully
int ret = waitpid(pid,&status,0);
if (ret == -1) {
printf("wait child failed\n");
/* code */
}else
printf("the wait id:%d\n", ret);//the ret == son pid
}
return 0;
}
