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ph649mxes 2 years ago
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commit 72dd5fc8ad
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exit.c
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/*
* linux/kernel/exit.c
*
* (C) 1991 Linus Torvalds
*/
#include <errno.h>
#include <signal.h>
#include <sys/wait.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/tty.h>
#include <asm/segment.h>
#include <unistd.h>//
int sys_pause(void);
int sys_close(int fd);
void* thread_value[4096] = {};//
void release(struct task_struct * p)
{
int i;
if (!p)
return;
for (i=1 ; i<NR_TASKS ; i++)
if (task[i]==p) {
task[i]=NULL;
free_page((long)p);
schedule();
return;
}
panic("trying to release non-existent task");
}
static inline int send_sig(long sig,struct task_struct * p,int priv)
{
if (!p || sig<1 || sig>32)
return -EINVAL;
if (priv || (current->euid==p->euid) || suser())
p->signal |= (1<<(sig-1));
else
return -EPERM;
return 0;
}
static void kill_session(void)
{
struct task_struct **p = NR_TASKS + task;
while (--p > &FIRST_TASK) {
if (*p && (*p)->session == current->session)
(*p)->signal |= 1<<(SIGHUP-1);
}
}
/*
* XXX need to check permissions needed to send signals to process
* groups, etc. etc. kill() permissions semantics are tricky!
*/
int sys_kill(int pid,int sig)
{
struct task_struct **p = NR_TASKS + task;
int err, retval = 0;
if (!pid) while (--p > &FIRST_TASK) {
if (*p && (*p)->pgrp == current->pid)
if (err=send_sig(sig,*p,1))
retval = err;
} else if (pid>0) while (--p > &FIRST_TASK) {
if (*p && (*p)->pid == pid)
if (err=send_sig(sig,*p,0))
retval = err;
} else if (pid == -1) while (--p > &FIRST_TASK)
if (err = send_sig(sig,*p,0))
retval = err;
else while (--p > &FIRST_TASK)
if (*p && (*p)->pgrp == -pid)
if (err = send_sig(sig,*p,0))
retval = err;
return retval;
}
static void tell_father(int pid)
{
int i;
if (pid)
for (i=0;i<NR_TASKS;i++) {
if (!task[i])
continue;
if (task[i]->pid != pid)
continue;
task[i]->signal |= (1<<(SIGCHLD-1));
return;
}
/* if we don't find any fathers, we just release ourselves */
/* This is not really OK. Must change it to make father 1 */
printk("BAD BAD - no father found\n\r");
release(current);
}
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 sys_exit(int error_code)
{
return do_exit((error_code&0xff)<<8);
}
int sys_waitpid(pid_t pid,unsigned long * stat_addr, int options)
{
int flag, code;
struct task_struct ** p;
verify_area(stat_addr,4);
repeat:
flag=0;
for(p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
if (!*p || *p == current)
continue;
if ((*p)->father != current->pid)
continue;
if (pid>0) {
if ((*p)->pid != pid)
continue;
} else if (!pid) {
if ((*p)->pgrp != current->pgrp)
continue;
} else if (pid != -1) {
if ((*p)->pgrp != -pid)
continue;
}
switch ((*p)->state) {
case TASK_STOPPED:
if (!(options & WUNTRACED))
continue;
put_fs_long(0x7f,stat_addr);
return (*p)->pid;
case TASK_ZOMBIE:
current->cutime += (*p)->utime;
current->cstime += (*p)->stime;
flag = (*p)->pid;
code = (*p)->exit_code;
release(*p);
put_fs_long(code,stat_addr);
return flag;
default:
flag=1;
continue;
}
}
if (flag) {
if (options & WNOHANG)
return 0;
current->state=TASK_INTERRUPTIBLE;
schedule();
if (!(current->signal &= ~(1<<(SIGCHLD-1))))
goto repeat;
else
return -EINTR;
}
return -ECHILD;
}
int sys_thread_exit(void* value_ptr) /* ϵͳ<CFB5><CDB3><EFBFBD><EFBFBD>thread_exitʵ<74>ֺ<EFBFBD><D6BA><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ο<EFBFBD><CEBF><EFBFBD>do_exit */
{
int i;
pthread_t thread;
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;
thread = current->pid; /*<2A><>ǰ<EFBFBD>߳<EFBFBD>ID*/
thread_value[thread] = value_ptr;
tell_father(current->father);
schedule();
return (-1);
}
int sys_thread_join(pthread_t thread, void** value_ptr) /* ϵͳ<CFB5><CDB3><EFBFBD><EFBFBD>thread_exitʵ<74>ֺ<EFBFBD><D6BA><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ο<EFBFBD><CEBF><EFBFBD>wait_pid */
{
if (thread <= 0 || value_ptr == NULL)
{
printk("Error:thread joining failed!\n");
sys_exit(0);
}
int flag;
struct task_struct** p;
repeat:
flag = 0;
for (p = &LAST_TASK; p > &FIRST_TASK; --p)
{
if (!*p || *p == current)
continue;
if ((*p)->father != current->pid)
continue;
if ((*p)->pid != thread)
continue;
switch ((*p)->state)
{
case TASK_STOPPED:
break;
case TASK_ZOMBIE:
current->cutime += (*p)->utime;
current->cstime += (*p)->stime;
release(*p);
put_fs_long(thread_value[thread], value_ptr);
return 0;
default:
flag = 1;
break;
}
}
if (flag) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (!(current->signal &= ~(1 << (SIGCHLD - 1))))
goto repeat;
else
return -EINTR;
}
return -ECHILD;
}
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