Import changeset

1 files changed, 596 insertions, 0 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
new file mode 100644
index 000000000000..c747f547b182
--- /dev/null
+++ b/kernel/exit.c
@@ -0,0 +1,596 @@
+/*
+ *  linux/kernel/exit.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <linux/config.h>
+#include <linux/malloc.h>
+#include <linux/interrupt.h>
+#include <linux/smp_lock.h>
+#include <linux/module.h>
+#ifdef CONFIG_BSD_PROCESS_ACCT
+#include <linux/acct.h>
+#endif
+
+#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 void release_task(struct task_struct * p)
+{
+	if (p != current) {
+#ifdef CONFIG_SMP
+		/*
+		 * Wait to make sure the process isn't on the
+		 * runqueue (active on some other CPU still)
+		 */
+		for (;;) {
+			task_lock(p);
+			if (!p->has_cpu)
+				break;
+			task_unlock(p);
+			do {
+				barrier();
+			} while (p->has_cpu);
+		}
+		task_unlock(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;
+		/*
+		 * Potentially available timeslices are retrieved
+		 * here - this way the parent does not get penalized
+		 * for creating too many processes.
+		 *
+		 * (this cannot be used to artificially 'generate'
+		 * timeslices, because any timeslice recovered here
+		 * was given away by the parent in the first place.)
+		 */
+		current->counter += p->counter;
+		if (current->counter >= MAX_COUNTER)
+			current->counter = MAX_COUNTER;
+		free_task_struct(p);
+	} else {
+		printk("task releasing itself\n");
+	}
+}
+
+/*
+ * 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->p_pptr->pid == 1))
+			continue;
+		if ((p->p_pptr->pgrp != pgrp) &&
+		    (p->p_pptr->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;
+}
+
+/*
+ * When we die, we re-parent all our children.
+ * Try to give them to another thread in our process
+ * 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 */
+	reaper = next_thread(father);
+	if (reaper == father)
+		reaper = child_reaper;
+
+	for_each_task(p) {
+		if (p->p_opptr == father) {
+			/* We dont want people slaying init */
+			p->exit_signal = SIGCHLD;
+			p->self_exec_id++;
+			p->p_opptr = 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;
+		task_unlock(tsk);
+		enter_lazy_tlb(mm, current, smp_processor_id());
+		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->p_pptr;
+	
+	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 (current->p_cptr != NULL) {
+		p = current->p_cptr;
+		current->p_cptr = p->p_osptr;
+		p->p_ysptr = NULL;
+		p->ptrace = 0;
+
+		p->p_pptr = p->p_opptr;
+		p->p_osptr = p->p_pptr->p_cptr;
+		if (p->p_osptr)
+			p->p_osptr->p_ysptr = p;
+		p->p_pptr->p_cptr = p;
+		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);
+		}
+	}
+	write_unlock_irq(&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);
+
+fake_volatile:
+#ifdef CONFIG_BSD_PROCESS_ACCT
+	acct_process(code);
+#endif
+	__exit_mm(tsk);
+
+	lock_kernel();
+	sem_exit();
+	__exit_files(tsk);
+	__exit_fs(tsk);
+	exit_sighand(tsk);
+	exit_thread();
+
+	if (current->leader)
+		disassociate_ctty(1);
+
+	put_exec_domain(tsk->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 up_and_exit(struct semaphore *sem, long code)
+{
+	if (sem)
+		up(sem);
+	
+	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;
+	 	for (p = tsk->p_cptr ; p ; p = p->p_osptr) {
+			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);
+				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->p_opptr != p->p_pptr) {
+					write_lock_irq(&tasklist_lock);
+					REMOVE_LINKS(p);
+					p->p_pptr = p->p_opptr;
+					SET_LINKS(p);
+					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__)
+
+/*
+ * 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