kernel/exit.c - pub/scm/linux/kernel/git/joro/linux - Git at Google

 /*
  *  linux/kernel/exit.c
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  */

 #include <linux/config.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/smp_lock.h>
 #include <linux/module.h>
 #include <linux/completion.h>
 #include <linux/personality.h>
 #include <linux/tty.h>
 #include <linux/namespace.h>
 #include <linux/acct.h>
 #include <linux/file.h>
 #include <linux/binfmts.h>

 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/mmu_context.h>

 extern void sem_exit (void);
 extern struct task_struct *child_reaper;

 int getrusage(struct task_struct *, int, struct rusage *);

 static inline void __unhash_process(struct task_struct *p)
 {
 	struct dentry *proc_dentry;
 	write_lock_irq(&tasklist_lock);
 	nr_threads--;
 	unhash_pid(p);
 	REMOVE_LINKS(p);
 	list_del(&p->thread_group);
 	p->pid = 0;
 	proc_dentry = p->proc_dentry;
 	if (unlikely(proc_dentry != NULL)) {
 		spin_lock(&dcache_lock);
 		if (!list_empty(&proc_dentry->d_hash)) {
 			dget_locked(proc_dentry);
 			list_del_init(&proc_dentry->d_hash);
 		} else
 			proc_dentry = NULL;
 		spin_unlock(&dcache_lock);
 	}
 	write_unlock_irq(&tasklist_lock);
 	if (unlikely(proc_dentry != NULL)) {
 		shrink_dcache_parent(proc_dentry);
 		dput(proc_dentry);
 	}
 }

 static void release_task(struct task_struct * p)
 {
 	if (p == current)
 		BUG();
 #ifdef CONFIG_SMP
 	wait_task_inactive(p);
 #endif
 	atomic_dec(&p->user->processes);
 	free_uid(p->user);
 	unhash_process(p);

 	release_thread(p);
 	current->cmin_flt += p->min_flt + p->cmin_flt;
 	current->cmaj_flt += p->maj_flt + p->cmaj_flt;
 	current->cnswap += p->nswap + p->cnswap;
 	sched_exit(p);
 	put_task_struct(p);
 }

 /* we are using it only for SMP init */

 void unhash_process(struct task_struct *p)
 {
 	return __unhash_process(p);
 }

 /*
  * This checks not only the pgrp, but falls back on the pid if no
  * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
  * without this...
  */
 int session_of_pgrp(int pgrp)
 {
 	struct task_struct *p;
 	int fallback;

 	fallback = -1;
 	read_lock(&tasklist_lock);
 	for_each_task(p) {
  		if (p->session <= 0)
  			continue;
 		if (p->pgrp == pgrp) {
 			fallback = p->session;
 			break;
 		}
 		if (p->pid == pgrp)
 			fallback = p->session;
 	}
 	read_unlock(&tasklist_lock);
 	return fallback;
 }

 /*
  * Determine if a process group is "orphaned", according to the POSIX
  * definition in 2.2.2.52.  Orphaned process groups are not to be affected
  * by terminal-generated stop signals.  Newly orphaned process groups are
  * to receive a SIGHUP and a SIGCONT.
  *
  * "I ask you, have you ever known what it is to be an orphan?"
  */
 static int will_become_orphaned_pgrp(int pgrp, struct task_struct * ignored_task)
 {
 	struct task_struct *p;

 	read_lock(&tasklist_lock);
 	for_each_task(p) {
 		if ((p == ignored_task) || (p->pgrp != pgrp) ||
 		    (p->state == TASK_ZOMBIE) ||
 		    (p->parent->pid == 1))
 			continue;
 		if ((p->parent->pgrp != pgrp) &&
 		    (p->parent->session == p->session)) {
 			read_unlock(&tasklist_lock);
  			return 0;
 		}
 	}
 	read_unlock(&tasklist_lock);
 	return 1;	/* (sighing) "Often!" */
 }

 int is_orphaned_pgrp(int pgrp)
 {
 	return will_become_orphaned_pgrp(pgrp, 0);
 }

 static inline int has_stopped_jobs(int pgrp)
 {
 	int retval = 0;
 	struct task_struct * p;

 	read_lock(&tasklist_lock);
 	for_each_task(p) {
 		if (p->pgrp != pgrp)
 			continue;
 		if (p->state != TASK_STOPPED)
 			continue;
 		retval = 1;
 		break;
 	}
 	read_unlock(&tasklist_lock);
 	return retval;
 }

 /**
  * reparent_to_init() - Reparent the calling kernel thread to the init task.
  *
  * If a kernel thread is launched as a result of a system call, or if
  * it ever exits, it should generally reparent itself to init so that
  * it is correctly cleaned up on exit.
  *
  * The various task state such as scheduling policy and priority may have
  * been inherited from a user process, so we reset them to sane values here.
  *
  * NOTE that reparent_to_init() gives the caller full capabilities.
  */
 void reparent_to_init(void)
 {
 	write_lock_irq(&tasklist_lock);

 	/* Reparent to init */
 	REMOVE_LINKS(current);
 	current->parent = child_reaper;
 	current->real_parent = child_reaper;
 	SET_LINKS(current);

 	/* Set the exit signal to SIGCHLD so we signal init on exit */
 	current->exit_signal = SIGCHLD;

 	current->ptrace = 0;
 	if ((current->policy == SCHED_OTHER) && (task_nice(current) < 0))
 		set_user_nice(current, 0);
 	/* cpus_allowed? */
 	/* rt_priority? */
 	/* signals? */
 	current->cap_effective = CAP_INIT_EFF_SET;
 	current->cap_inheritable = CAP_INIT_INH_SET;
 	current->cap_permitted = CAP_FULL_SET;
 	current->keep_capabilities = 0;
 	memcpy(current->rlim, init_task.rlim, sizeof(*(current->rlim)));
 	current->user = INIT_USER;

 	write_unlock_irq(&tasklist_lock);
 }

 /*
  *	Put all the gunge required to become a kernel thread without
  *	attached user resources in one place where it belongs.
  */

 void daemonize(void)
 {
 	struct fs_struct *fs;


 	/*
 	 * If we were started as result of loading a module, close all of the
 	 * user space pages.  We don't need them, and if we didn't close them
 	 * they would be locked into memory.
 	 */
 	exit_mm(current);

 	current->session = 1;
 	current->pgrp = 1;
 	current->tty = NULL;

 	/* Become as one with the init task */

 	exit_fs(current);	/* current->fs->count--; */
 	fs = init_task.fs;
 	current->fs = fs;
 	atomic_inc(&fs->count);
  	exit_files(current);
 	current->files = init_task.files;
 	atomic_inc(&current->files->count);
 }

 /*
  * When we die, we re-parent all our children.
  * Try to give them to another thread in our thread
  * group, and if no such member exists, give it to
  * the global child reaper process (ie "init")
  */
 static inline void forget_original_parent(struct task_struct * father)
 {
 	struct task_struct * p, *reaper;

 	read_lock(&tasklist_lock);

 	/* Next in our thread group, if they're not already exiting */
 	reaper = father;
 	do {
 		reaper = next_thread(reaper);
 		if (!(reaper->flags & PF_EXITING))
 			break;
 	} while (reaper != father);

 	if (reaper == father)
 		reaper = child_reaper;

 	for_each_task(p) {
 		if (p->real_parent == father) {
 			/* We dont want people slaying init */
 			p->exit_signal = SIGCHLD;
 			p->self_exec_id++;

 			/* Make sure we're not reparenting to ourselves */
 			if (p == reaper)
 				p->real_parent = child_reaper;
 			else
 				p->real_parent = reaper;

 			if (p->pdeath_signal) send_sig(p->pdeath_signal, p, 0);
 		}
 	}
 	read_unlock(&tasklist_lock);
 }

 static inline void close_files(struct files_struct * files)
 {
 	int i, j;

 	j = 0;
 	for (;;) {
 		unsigned long set;
 		i = j * __NFDBITS;
 		if (i >= files->max_fdset || i >= files->max_fds)
 			break;
 		set = files->open_fds->fds_bits[j++];
 		while (set) {
 			if (set & 1) {
 				struct file * file = xchg(&files->fd[i], NULL);
 				if (file)
 					filp_close(file, files);
 			}
 			i++;
 			set >>= 1;
 		}
 	}
 }

 void put_files_struct(struct files_struct *files)
 {
 	if (atomic_dec_and_test(&files->count)) {
 		close_files(files);
 		/*
 		 * Free the fd and fdset arrays if we expanded them.
 		 */
 		if (files->fd != &files->fd_array[0])
 			free_fd_array(files->fd, files->max_fds);
 		if (files->max_fdset > __FD_SETSIZE) {
 			free_fdset(files->open_fds, files->max_fdset);
 			free_fdset(files->close_on_exec, files->max_fdset);
 		}
 		kmem_cache_free(files_cachep, files);
 	}
 }

 static inline void __exit_files(struct task_struct *tsk)
 {
 	struct files_struct * files = tsk->files;

 	if (files) {
 		task_lock(tsk);
 		tsk->files = NULL;
 		task_unlock(tsk);
 		put_files_struct(files);
 	}
 }

 void exit_files(struct task_struct *tsk)
 {
 	__exit_files(tsk);
 }

 static inline void __put_fs_struct(struct fs_struct *fs)
 {
 	/* No need to hold fs->lock if we are killing it */
 	if (atomic_dec_and_test(&fs->count)) {
 		dput(fs->root);
 		mntput(fs->rootmnt);
 		dput(fs->pwd);
 		mntput(fs->pwdmnt);
 		if (fs->altroot) {
 			dput(fs->altroot);
 			mntput(fs->altrootmnt);
 		}
 		kmem_cache_free(fs_cachep, fs);
 	}
 }

 void put_fs_struct(struct fs_struct *fs)
 {
 	__put_fs_struct(fs);
 }

 static inline void __exit_fs(struct task_struct *tsk)
 {
 	struct fs_struct * fs = tsk->fs;

 	if (fs) {
 		task_lock(tsk);
 		tsk->fs = NULL;
 		task_unlock(tsk);
 		__put_fs_struct(fs);
 	}
 }

 void exit_fs(struct task_struct *tsk)
 {
 	__exit_fs(tsk);
 }

 /*
  * We can use these to temporarily drop into
  * "lazy TLB" mode and back.
  */
 struct mm_struct * start_lazy_tlb(void)
 {
 	struct mm_struct *mm = current->mm;
 	current->mm = NULL;
 	/* active_mm is still 'mm' */
 	atomic_inc(&mm->mm_count);
 	enter_lazy_tlb(mm, current, smp_processor_id());
 	return mm;
 }

 void end_lazy_tlb(struct mm_struct *mm)
 {
 	struct mm_struct *active_mm = current->active_mm;

 	current->mm = mm;
 	if (mm != active_mm) {
 		current->active_mm = mm;
 		activate_mm(active_mm, mm);
 	}
 	mmdrop(active_mm);
 }

 /*
  * Turn us into a lazy TLB process if we
  * aren't already..
  */
 static inline void __exit_mm(struct task_struct * tsk)
 {
 	struct mm_struct * mm = tsk->mm;

 	mm_release();
 	if (mm) {
 		atomic_inc(&mm->mm_count);
 		if (mm != tsk->active_mm) BUG();
 		/* more a memory barrier than a real lock */
 		task_lock(tsk);
 		tsk->mm = NULL;
 		enter_lazy_tlb(mm, current, smp_processor_id());
 		task_unlock(tsk);
 		mmput(mm);
 	}
 }

 void exit_mm(struct task_struct *tsk)
 {
 	__exit_mm(tsk);
 }

 /*
  * Send signals to all our closest relatives so that they know
  * to properly mourn us..
  */
 static void exit_notify(void)
 {
 	struct task_struct * p, *t;

 	forget_original_parent(current);
 	/*
 	 * Check to see if any process groups have become orphaned
 	 * as a result of our exiting, and if they have any stopped
 	 * jobs, send them a SIGHUP and then a SIGCONT.  (POSIX 3.2.2.2)
 	 *
 	 * Case i: Our father is in a different pgrp than we are
 	 * and we were the only connection outside, so our pgrp
 	 * is about to become orphaned.
 	 */

 	t = current->parent;

 	if ((t->pgrp != current->pgrp) &&
 	    (t->session == current->session) &&
 	    will_become_orphaned_pgrp(current->pgrp, current) &&
 	    has_stopped_jobs(current->pgrp)) {
 		kill_pg(current->pgrp,SIGHUP,1);
 		kill_pg(current->pgrp,SIGCONT,1);
 	}

 	/* Let father know we died
 	 *
 	 * Thread signals are configurable, but you aren't going to use
 	 * that to send signals to arbitary processes.
 	 * That stops right now.
 	 *
 	 * If the parent exec id doesn't match the exec id we saved
 	 * when we started then we know the parent has changed security
 	 * domain.
 	 *
 	 * If our self_exec id doesn't match our parent_exec_id then
 	 * we have changed execution domain as these two values started
 	 * the same after a fork.
 	 *
 	 */

 	if(current->exit_signal != SIGCHLD &&
 	    ( current->parent_exec_id != t->self_exec_id  ||
 	      current->self_exec_id != current->parent_exec_id)
 	    && !capable(CAP_KILL))
 		current->exit_signal = SIGCHLD;


 	/*
 	 * This loop does two things:
 	 *
   	 * A.  Make init inherit all the child processes
 	 * B.  Check to see if any process groups have become orphaned
 	 *	as a result of our exiting, and if they have any stopped
 	 *	jobs, send them a SIGHUP and then a SIGCONT.  (POSIX 3.2.2.2)
 	 */

 	write_lock_irq(&tasklist_lock);
 	current->state = TASK_ZOMBIE;
 	do_notify_parent(current, current->exit_signal);
 	while ((p = eldest_child(current))) {
 		list_del_init(&p->sibling);
 		p->ptrace = 0;

 		p->parent = p->real_parent;
 		list_add_tail(&p->sibling,&p->parent->children);
 		if (p->state == TASK_ZOMBIE)
 			do_notify_parent(p, p->exit_signal);
 		/*
 		 * process group orphan check
 		 * Case ii: Our child is in a different pgrp
 		 * than we are, and it was the only connection
 		 * outside, so the child pgrp is now orphaned.
 		 */
 		if ((p->pgrp != current->pgrp) &&
 		    (p->session == current->session)) {
 			int pgrp = p->pgrp;

 			write_unlock_irq(&tasklist_lock);
 			if (is_orphaned_pgrp(pgrp) && has_stopped_jobs(pgrp)) {
 				kill_pg(pgrp,SIGHUP,1);
 				kill_pg(pgrp,SIGCONT,1);
 			}
 			write_lock_irq(&tasklist_lock);
 		}
 	}

 	/*
 	 * No need to unlock IRQs, we'll schedule() immediately
 	 * anyway. In the preemption case this also makes it
 	 * impossible for the task to get runnable again (thus
 	 * the "_raw_" unlock - to make sure we don't try to
 	 * preempt here).
 	 */
 	_raw_write_unlock(&tasklist_lock);
 }

 NORET_TYPE void do_exit(long code)
 {
 	struct task_struct *tsk = current;

 	if (in_interrupt())
 		panic("Aiee, killing interrupt handler!");
 	if (!tsk->pid)
 		panic("Attempted to kill the idle task!");
 	if (tsk->pid == 1)
 		panic("Attempted to kill init!");
 	tsk->flags |= PF_EXITING;
 	del_timer_sync(&tsk->real_timer);

 	if (unlikely(preempt_get_count()))
 		printk(KERN_ERR "error: %s[%d] exited with preempt_count %d\n",
 				current->comm, current->pid,
 				preempt_get_count());

 fake_volatile:
 	acct_process(code);
 	__exit_mm(tsk);

 	sem_exit();
 	__exit_files(tsk);
 	__exit_fs(tsk);
 	exit_namespace(tsk);
 	exit_sighand(tsk);
 	exit_thread();

 	if (current->leader)
 		disassociate_ctty(1);

 	put_exec_domain(tsk->thread_info->exec_domain);
 	if (tsk->binfmt && tsk->binfmt->module)
 		__MOD_DEC_USE_COUNT(tsk->binfmt->module);

 	tsk->exit_code = code;
 	exit_notify();
 	schedule();
 	BUG();
 /*
  * In order to get rid of the "volatile function does return" message
  * I did this little loop that confuses gcc to think do_exit really
  * is volatile. In fact it's schedule() that is volatile in some
  * circumstances: when current->state = ZOMBIE, schedule() never
  * returns.
  *
  * In fact the natural way to do all this is to have the label and the
  * goto right after each other, but I put the fake_volatile label at
  * the start of the function just in case something /really/ bad
  * happens, and the schedule returns. This way we can try again. I'm
  * not paranoid: it's just that everybody is out to get me.
  */
 	goto fake_volatile;
 }

 NORET_TYPE void complete_and_exit(struct completion *comp, long code)
 {
 	if (comp)
 		complete(comp);

 	do_exit(code);
 }

 asmlinkage long sys_exit(int error_code)
 {
 	do_exit((error_code&0xff)<<8);
 }

 asmlinkage long sys_wait4(pid_t pid,unsigned int * stat_addr, int options, struct rusage * ru)
 {
 	int flag, retval;
 	DECLARE_WAITQUEUE(wait, current);
 	struct task_struct *tsk;

 	if (options & ~(WNOHANG|WUNTRACED|__WNOTHREAD|__WCLONE|__WALL))
 		return -EINVAL;

 	add_wait_queue(&current->wait_chldexit,&wait);
 repeat:
 	flag = 0;
 	current->state = TASK_INTERRUPTIBLE;
 	read_lock(&tasklist_lock);
 	tsk = current;
 	do {
 		struct task_struct *p;
 		struct list_head *_p;
 		list_for_each(_p,&tsk->children) {
 			p = list_entry(_p,struct task_struct,sibling);
 			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;
 			}
 			/* Wait for all children (clone and not) if __WALL is set;
 			 * otherwise, wait for clone children *only* if __WCLONE is
 			 * set; otherwise, wait for non-clone children *only*.  (Note:
 			 * A "clone" child here is one that reports to its parent
 			 * using a signal other than SIGCHLD.) */
 			if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
 			    && !(options & __WALL))
 				continue;
 			flag = 1;
 			switch (p->state) {
 			case TASK_STOPPED:
 				if (!p->exit_code)
 					continue;
 				if (!(options & WUNTRACED) && !(p->ptrace & PT_PTRACED))
 					continue;
 				read_unlock(&tasklist_lock);

 				/* move to end of parent's list to avoid starvation */
 				write_lock_irq(&tasklist_lock);
 				remove_parent(p);
 				add_parent(p, p->parent);
 				write_unlock_irq(&tasklist_lock);
 				retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
 				if (!retval && stat_addr)
 					retval = put_user((p->exit_code << 8) | 0x7f, stat_addr);
 				if (!retval) {
 					p->exit_code = 0;
 					retval = p->pid;
 				}
 				goto end_wait4;
 			case TASK_ZOMBIE:
 				current->times.tms_cutime += p->times.tms_utime + p->times.tms_cutime;
 				current->times.tms_cstime += p->times.tms_stime + p->times.tms_cstime;
 				read_unlock(&tasklist_lock);
 				retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
 				if (!retval && stat_addr)
 					retval = put_user(p->exit_code, stat_addr);
 				if (retval)
 					goto end_wait4;
 				retval = p->pid;
 				if (p->real_parent != p->parent) {
 					write_lock_irq(&tasklist_lock);
 					remove_parent(p);
 					p->parent = p->real_parent;
 					add_parent(p, p->parent);
 					do_notify_parent(p, SIGCHLD);
 					write_unlock_irq(&tasklist_lock);
 				} else
 					release_task(p);
 				goto end_wait4;
 			default:
 				continue;
 			}
 		}
 		if (options & __WNOTHREAD)
 			break;
 		tsk = next_thread(tsk);
 	} while (tsk != current);
 	read_unlock(&tasklist_lock);
 	if (flag) {
 		retval = 0;
 		if (options & WNOHANG)
 			goto end_wait4;
 		retval = -ERESTARTSYS;
 		if (signal_pending(current))
 			goto end_wait4;
 		schedule();
 		goto repeat;
 	}
 	retval = -ECHILD;
 end_wait4:
 	current->state = TASK_RUNNING;
 	remove_wait_queue(&current->wait_chldexit,&wait);
 	return retval;
 }

 #if !defined(__alpha__) && !defined(__ia64__) && !defined(__arm__)

 /*
  * sys_waitpid() remains for compatibility. waitpid() should be
  * implemented by calling sys_wait4() from libc.a.
  */
 asmlinkage long sys_waitpid(pid_t pid,unsigned int * stat_addr, int options)
 {
 	return sys_wait4(pid, stat_addr, options, NULL);
 }

 #endif
	/*
	* linux/kernel/exit.c
	*
	* Copyright (C) 1991, 1992 Linus Torvalds
	*/

	#include <linux/config.h>
	#include <linux/mm.h>
	#include <linux/slab.h>
	#include <linux/interrupt.h>
	#include <linux/smp_lock.h>
	#include <linux/module.h>
	#include <linux/completion.h>
	#include <linux/personality.h>
	#include <linux/tty.h>
	#include <linux/namespace.h>
	#include <linux/acct.h>
	#include <linux/file.h>
	#include <linux/binfmts.h>

	#include <asm/uaccess.h>
	#include <asm/pgtable.h>
	#include <asm/mmu_context.h>

	extern void sem_exit (void);
	extern struct task_struct *child_reaper;

	int getrusage(struct task_struct , int, struct rusage );

	static inline void __unhash_process(struct task_struct *p)
	{
	struct dentry *proc_dentry;
	write_lock_irq(&tasklist_lock);
	nr_threads--;
	unhash_pid(p);
	REMOVE_LINKS(p);
	list_del(&p->thread_group);
	p->pid = 0;
	proc_dentry = p->proc_dentry;
	if (unlikely(proc_dentry != NULL)) {
	spin_lock(&dcache_lock);
	if (!list_empty(&proc_dentry->d_hash)) {
	dget_locked(proc_dentry);
	list_del_init(&proc_dentry->d_hash);
	} else
	proc_dentry = NULL;
	spin_unlock(&dcache_lock);
	}
	write_unlock_irq(&tasklist_lock);
	if (unlikely(proc_dentry != NULL)) {
	shrink_dcache_parent(proc_dentry);
	dput(proc_dentry);
	}
	}

	static void release_task(struct task_struct * p)
	{
	if (p == current)
	BUG();
	#ifdef CONFIG_SMP
	wait_task_inactive(p);
	#endif
	atomic_dec(&p->user->processes);
	free_uid(p->user);
	unhash_process(p);

	release_thread(p);
	current->cmin_flt += p->min_flt + p->cmin_flt;
	current->cmaj_flt += p->maj_flt + p->cmaj_flt;
	current->cnswap += p->nswap + p->cnswap;
	sched_exit(p);
	put_task_struct(p);
	}

	/* we are using it only for SMP init */

	void unhash_process(struct task_struct *p)
	{
	return __unhash_process(p);
	}

	/*
	* This checks not only the pgrp, but falls back on the pid if no
	* satisfactory pgrp is found. I dunno - gdb doesn't work correctly
	* without this...
	*/
	int session_of_pgrp(int pgrp)
	{
	struct task_struct *p;
	int fallback;

	fallback = -1;
	read_lock(&tasklist_lock);
	for_each_task(p) {
	if (p->session <= 0)
	continue;
	if (p->pgrp == pgrp) {
	fallback = p->session;
	break;
	}
	if (p->pid == pgrp)
	fallback = p->session;
	}
	read_unlock(&tasklist_lock);
	return fallback;
	}

	/*
	* Determine if a process group is "orphaned", according to the POSIX
	* definition in 2.2.2.52. Orphaned process groups are not to be affected
	* by terminal-generated stop signals. Newly orphaned process groups are
	* to receive a SIGHUP and a SIGCONT.
	*
	* "I ask you, have you ever known what it is to be an orphan?"
	*/
	static int will_become_orphaned_pgrp(int pgrp, struct task_struct * ignored_task)
	{
	struct task_struct *p;

	read_lock(&tasklist_lock);
	for_each_task(p) {
	if ((p == ignored_task) \|\| (p->pgrp != pgrp) \|\|
	(p->state == TASK_ZOMBIE) \|\|
	(p->parent->pid == 1))
	continue;
	if ((p->parent->pgrp != pgrp) &&
	(p->parent->session == p->session)) {
	read_unlock(&tasklist_lock);
	return 0;
	}
	}
	read_unlock(&tasklist_lock);
	return 1; /* (sighing) "Often!" */
	}

	int is_orphaned_pgrp(int pgrp)
	{
	return will_become_orphaned_pgrp(pgrp, 0);
	}

	static inline int has_stopped_jobs(int pgrp)
	{
	int retval = 0;
	struct task_struct * p;

	read_lock(&tasklist_lock);
	for_each_task(p) {
	if (p->pgrp != pgrp)
	continue;
	if (p->state != TASK_STOPPED)
	continue;
	retval = 1;
	break;
	}
	read_unlock(&tasklist_lock);
	return retval;
	}

	/**
	* reparent_to_init() - Reparent the calling kernel thread to the init task.
	*
	* If a kernel thread is launched as a result of a system call, or if
	* it ever exits, it should generally reparent itself to init so that
	* it is correctly cleaned up on exit.
	*
	* The various task state such as scheduling policy and priority may have
	* been inherited from a user process, so we reset them to sane values here.
	*
	* NOTE that reparent_to_init() gives the caller full capabilities.
	*/
	void reparent_to_init(void)
	{
	write_lock_irq(&tasklist_lock);

	/* Reparent to init */
	REMOVE_LINKS(current);
	current->parent = child_reaper;
	current->real_parent = child_reaper;
	SET_LINKS(current);

	/* Set the exit signal to SIGCHLD so we signal init on exit */
	current->exit_signal = SIGCHLD;

	current->ptrace = 0;
	if ((current->policy == SCHED_OTHER) && (task_nice(current) < 0))
	set_user_nice(current, 0);
	/* cpus_allowed? */
	/* rt_priority? */
	/* signals? */
	current->cap_effective = CAP_INIT_EFF_SET;
	current->cap_inheritable = CAP_INIT_INH_SET;
	current->cap_permitted = CAP_FULL_SET;
	current->keep_capabilities = 0;
	memcpy(current->rlim, init_task.rlim, sizeof(*(current->rlim)));
	current->user = INIT_USER;

	write_unlock_irq(&tasklist_lock);
	}

	/*
	* Put all the gunge required to become a kernel thread without
	* attached user resources in one place where it belongs.
	*/

	void daemonize(void)
	{
	struct fs_struct *fs;


	/*
	* If we were started as result of loading a module, close all of the
	* user space pages. We don't need them, and if we didn't close them
	* they would be locked into memory.
	*/
	exit_mm(current);

	current->session = 1;
	current->pgrp = 1;
	current->tty = NULL;

	/* Become as one with the init task */

	exit_fs(current); /* current->fs->count--; */
	fs = init_task.fs;
	current->fs = fs;
	atomic_inc(&fs->count);
	exit_files(current);
	current->files = init_task.files;
	atomic_inc(&current->files->count);
	}

	/*
	* When we die, we re-parent all our children.
	* Try to give them to another thread in our thread
	* group, and if no such member exists, give it to
	* the global child reaper process (ie "init")
	*/
	static inline void forget_original_parent(struct task_struct * father)
	{
	struct task_struct * p, *reaper;

	read_lock(&tasklist_lock);

	/* Next in our thread group, if they're not already exiting */
	reaper = father;
	do {
	reaper = next_thread(reaper);
	if (!(reaper->flags & PF_EXITING))
	break;
	} while (reaper != father);

	if (reaper == father)
	reaper = child_reaper;

	for_each_task(p) {
	if (p->real_parent == father) {
	/* We dont want people slaying init */
	p->exit_signal = SIGCHLD;
	p->self_exec_id++;

	/* Make sure we're not reparenting to ourselves */
	if (p == reaper)
	p->real_parent = child_reaper;
	else
	p->real_parent = reaper;

	if (p->pdeath_signal) send_sig(p->pdeath_signal, p, 0);
	}
	}
	read_unlock(&tasklist_lock);
	}

	static inline void close_files(struct files_struct * files)
	{
	int i, j;

	j = 0;
	for (;;) {
	unsigned long set;
	i = j * __NFDBITS;
	if (i >= files->max_fdset \|\| i >= files->max_fds)
	break;
	set = files->open_fds->fds_bits[j++];
	while (set) {
	if (set & 1) {
	struct file * file = xchg(&files->fd[i], NULL);
	if (file)
	filp_close(file, files);
	}
	i++;
	set >>= 1;
	}
	}
	}

	void put_files_struct(struct files_struct *files)
	{
	if (atomic_dec_and_test(&files->count)) {
	close_files(files);
	/*
	* Free the fd and fdset arrays if we expanded them.
	*/
	if (files->fd != &files->fd_array[0])
	free_fd_array(files->fd, files->max_fds);
	if (files->max_fdset > __FD_SETSIZE) {
	free_fdset(files->open_fds, files->max_fdset);
	free_fdset(files->close_on_exec, files->max_fdset);
	}
	kmem_cache_free(files_cachep, files);
	}
	}

	static inline void __exit_files(struct task_struct *tsk)
	{
	struct files_struct * files = tsk->files;

	if (files) {
	task_lock(tsk);
	tsk->files = NULL;
	task_unlock(tsk);
	put_files_struct(files);
	}
	}

	void exit_files(struct task_struct *tsk)
	{
	__exit_files(tsk);
	}

	static inline void __put_fs_struct(struct fs_struct *fs)
	{
	/* No need to hold fs->lock if we are killing it */
	if (atomic_dec_and_test(&fs->count)) {
	dput(fs->root);
	mntput(fs->rootmnt);
	dput(fs->pwd);
	mntput(fs->pwdmnt);
	if (fs->altroot) {
	dput(fs->altroot);
	mntput(fs->altrootmnt);
	}
	kmem_cache_free(fs_cachep, fs);
	}
	}

	void put_fs_struct(struct fs_struct *fs)
	{
	__put_fs_struct(fs);
	}

	static inline void __exit_fs(struct task_struct *tsk)
	{
	struct fs_struct * fs = tsk->fs;

	if (fs) {
	task_lock(tsk);
	tsk->fs = NULL;
	task_unlock(tsk);
	__put_fs_struct(fs);
	}
	}

	void exit_fs(struct task_struct *tsk)
	{
	__exit_fs(tsk);
	}

	/*
	* We can use these to temporarily drop into
	* "lazy TLB" mode and back.
	*/
	struct mm_struct * start_lazy_tlb(void)
	{
	struct mm_struct *mm = current->mm;
	current->mm = NULL;
	/* active_mm is still 'mm' */
	atomic_inc(&mm->mm_count);
	enter_lazy_tlb(mm, current, smp_processor_id());
	return mm;
	}

	void end_lazy_tlb(struct mm_struct *mm)
	{
	struct mm_struct *active_mm = current->active_mm;

	current->mm = mm;
	if (mm != active_mm) {
	current->active_mm = mm;
	activate_mm(active_mm, mm);
	}
	mmdrop(active_mm);
	}

	/*
	* Turn us into a lazy TLB process if we
	* aren't already..
	*/
	static inline void __exit_mm(struct task_struct * tsk)
	{
	struct mm_struct * mm = tsk->mm;

	mm_release();
	if (mm) {
	atomic_inc(&mm->mm_count);
	if (mm != tsk->active_mm) BUG();
	/* more a memory barrier than a real lock */
	task_lock(tsk);
	tsk->mm = NULL;
	enter_lazy_tlb(mm, current, smp_processor_id());
	task_unlock(tsk);
	mmput(mm);
	}
	}

	void exit_mm(struct task_struct *tsk)
	{
	__exit_mm(tsk);
	}

	/*
	* Send signals to all our closest relatives so that they know
	* to properly mourn us..
	*/
	static void exit_notify(void)
	{
	struct task_struct * p, *t;

	forget_original_parent(current);
	/*
	* Check to see if any process groups have become orphaned
	* as a result of our exiting, and if they have any stopped
	* jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
	*
	* Case i: Our father is in a different pgrp than we are
	* and we were the only connection outside, so our pgrp
	* is about to become orphaned.
	*/

	t = current->parent;

	if ((t->pgrp != current->pgrp) &&
	(t->session == current->session) &&
	will_become_orphaned_pgrp(current->pgrp, current) &&
	has_stopped_jobs(current->pgrp)) {
	kill_pg(current->pgrp,SIGHUP,1);
	kill_pg(current->pgrp,SIGCONT,1);
	}

	/* Let father know we died
	*
	* Thread signals are configurable, but you aren't going to use
	* that to send signals to arbitary processes.
	* That stops right now.
	*
	* If the parent exec id doesn't match the exec id we saved
	* when we started then we know the parent has changed security
	* domain.
	*
	* If our self_exec id doesn't match our parent_exec_id then
	* we have changed execution domain as these two values started
	* the same after a fork.
	*
	*/

	if(current->exit_signal != SIGCHLD &&
	( current->parent_exec_id != t->self_exec_id \|\|
	current->self_exec_id != current->parent_exec_id)
	&& !capable(CAP_KILL))
	current->exit_signal = SIGCHLD;


	/*
	* This loop does two things:
	*
	* A. Make init inherit all the child processes
	* B. Check to see if any process groups have become orphaned
	* as a result of our exiting, and if they have any stopped
	* jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
	*/

	write_lock_irq(&tasklist_lock);
	current->state = TASK_ZOMBIE;
	do_notify_parent(current, current->exit_signal);
	while ((p = eldest_child(current))) {
	list_del_init(&p->sibling);
	p->ptrace = 0;

	p->parent = p->real_parent;
	list_add_tail(&p->sibling,&p->parent->children);
	if (p->state == TASK_ZOMBIE)
	do_notify_parent(p, p->exit_signal);
	/*
	* process group orphan check
	* Case ii: Our child is in a different pgrp
	* than we are, and it was the only connection
	* outside, so the child pgrp is now orphaned.
	*/
	if ((p->pgrp != current->pgrp) &&
	(p->session == current->session)) {
	int pgrp = p->pgrp;

	write_unlock_irq(&tasklist_lock);
	if (is_orphaned_pgrp(pgrp) && has_stopped_jobs(pgrp)) {
	kill_pg(pgrp,SIGHUP,1);
	kill_pg(pgrp,SIGCONT,1);
	}
	write_lock_irq(&tasklist_lock);
	}
	}

	/*
	* No need to unlock IRQs, we'll schedule() immediately
	* anyway. In the preemption case this also makes it
	* impossible for the task to get runnable again (thus
	* the "_raw_" unlock - to make sure we don't try to
	* preempt here).
	*/
	_raw_write_unlock(&tasklist_lock);
	}

	NORET_TYPE void do_exit(long code)
	{
	struct task_struct *tsk = current;

	if (in_interrupt())
	panic("Aiee, killing interrupt handler!");
	if (!tsk->pid)
	panic("Attempted to kill the idle task!");
	if (tsk->pid == 1)
	panic("Attempted to kill init!");
	tsk->flags \|= PF_EXITING;
	del_timer_sync(&tsk->real_timer);

	if (unlikely(preempt_get_count()))
	printk(KERN_ERR "error: %s[%d] exited with preempt_count %d\n",
	current->comm, current->pid,
	preempt_get_count());

	fake_volatile:
	acct_process(code);
	__exit_mm(tsk);

	sem_exit();
	__exit_files(tsk);
	__exit_fs(tsk);
	exit_namespace(tsk);
	exit_sighand(tsk);
	exit_thread();

	if (current->leader)
	disassociate_ctty(1);

	put_exec_domain(tsk->thread_info->exec_domain);
	if (tsk->binfmt && tsk->binfmt->module)
	__MOD_DEC_USE_COUNT(tsk->binfmt->module);

	tsk->exit_code = code;
	exit_notify();
	schedule();
	BUG();
	/*
	* In order to get rid of the "volatile function does return" message
	* I did this little loop that confuses gcc to think do_exit really
	* is volatile. In fact it's schedule() that is volatile in some
	* circumstances: when current->state = ZOMBIE, schedule() never
	* returns.
	*
	* In fact the natural way to do all this is to have the label and the
	* goto right after each other, but I put the fake_volatile label at
	* the start of the function just in case something /really/ bad
	* happens, and the schedule returns. This way we can try again. I'm
	* not paranoid: it's just that everybody is out to get me.
	*/
	goto fake_volatile;
	}

	NORET_TYPE void complete_and_exit(struct completion *comp, long code)
	{
	if (comp)
	complete(comp);

	do_exit(code);
	}

	asmlinkage long sys_exit(int error_code)
	{
	do_exit((error_code&0xff)<<8);
	}

	asmlinkage long sys_wait4(pid_t pid,unsigned int * stat_addr, int options, struct rusage * ru)
	{
	int flag, retval;
	DECLARE_WAITQUEUE(wait, current);
	struct task_struct *tsk;

	if (options & ~(WNOHANG\|WUNTRACED\|__WNOTHREAD\|__WCLONE\|__WALL))
	return -EINVAL;

	add_wait_queue(&current->wait_chldexit,&wait);
	repeat:
	flag = 0;
	current->state = TASK_INTERRUPTIBLE;
	read_lock(&tasklist_lock);
	tsk = current;
	do {
	struct task_struct *p;
	struct list_head *_p;
	list_for_each(_p,&tsk->children) {
	p = list_entry(_p,struct task_struct,sibling);
	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;
	}
	/* Wait for all children (clone and not) if __WALL is set;
	* otherwise, wait for clone children only if __WCLONE is
	* set; otherwise, wait for non-clone children only. (Note:
	* A "clone" child here is one that reports to its parent
	* using a signal other than SIGCHLD.) */
	if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
	&& !(options & __WALL))
	continue;
	flag = 1;
	switch (p->state) {
	case TASK_STOPPED:
	if (!p->exit_code)
	continue;
	if (!(options & WUNTRACED) && !(p->ptrace & PT_PTRACED))
	continue;
	read_unlock(&tasklist_lock);

	/* move to end of parent's list to avoid starvation */
	write_lock_irq(&tasklist_lock);
	remove_parent(p);
	add_parent(p, p->parent);
	write_unlock_irq(&tasklist_lock);
	retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
	if (!retval && stat_addr)
	retval = put_user((p->exit_code << 8) \| 0x7f, stat_addr);
	if (!retval) {
	p->exit_code = 0;
	retval = p->pid;
	}
	goto end_wait4;
	case TASK_ZOMBIE:
	current->times.tms_cutime += p->times.tms_utime + p->times.tms_cutime;
	current->times.tms_cstime += p->times.tms_stime + p->times.tms_cstime;
	read_unlock(&tasklist_lock);
	retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
	if (!retval && stat_addr)
	retval = put_user(p->exit_code, stat_addr);
	if (retval)
	goto end_wait4;
	retval = p->pid;
	if (p->real_parent != p->parent) {
	write_lock_irq(&tasklist_lock);
	remove_parent(p);
	p->parent = p->real_parent;
	add_parent(p, p->parent);
	do_notify_parent(p, SIGCHLD);
	write_unlock_irq(&tasklist_lock);
	} else
	release_task(p);
	goto end_wait4;
	default:
	continue;
	}
	}
	if (options & __WNOTHREAD)
	break;
	tsk = next_thread(tsk);
	} while (tsk != current);
	read_unlock(&tasklist_lock);
	if (flag) {
	retval = 0;
	if (options & WNOHANG)
	goto end_wait4;
	retval = -ERESTARTSYS;
	if (signal_pending(current))
	goto end_wait4;
	schedule();
	goto repeat;
	}
	retval = -ECHILD;
	end_wait4:
	current->state = TASK_RUNNING;
	remove_wait_queue(&current->wait_chldexit,&wait);
	return retval;
	}

	#if !defined(__alpha__) && !defined(__ia64__) && !defined(__arm__)

	/*
	* sys_waitpid() remains for compatibility. waitpid() should be
	* implemented by calling sys_wait4() from libc.a.
	*/
	asmlinkage long sys_waitpid(pid_t pid,unsigned int * stat_addr, int options)
	{
	return sys_wait4(pid, stat_addr, options, NULL);
	}

	#endif