mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-05 20:04:19 +08:00
35f5cad8c4
This patch reverts 'CONFIG_SMP && thread_group_empty()' optimization in sys_times(). The reason is that the next patch breaks memory ordering which is needed for that optimization. tasklist_lock in sys_times() will be eliminated completely by further patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1645 lines
41 KiB
C
1645 lines
41 KiB
C
/*
|
|
* 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/capability.h>
|
|
#include <linux/completion.h>
|
|
#include <linux/personality.h>
|
|
#include <linux/tty.h>
|
|
#include <linux/namespace.h>
|
|
#include <linux/key.h>
|
|
#include <linux/security.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/acct.h>
|
|
#include <linux/file.h>
|
|
#include <linux/binfmts.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/profile.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/mempolicy.h>
|
|
#include <linux/cpuset.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/signal.h>
|
|
#include <linux/posix-timers.h>
|
|
#include <linux/cn_proc.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/futex.h>
|
|
#include <linux/compat.h>
|
|
|
|
#include <asm/uaccess.h>
|
|
#include <asm/unistd.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 __user *);
|
|
|
|
static void exit_mm(struct task_struct * tsk);
|
|
|
|
static void __unhash_process(struct task_struct *p)
|
|
{
|
|
nr_threads--;
|
|
detach_pid(p, PIDTYPE_PID);
|
|
detach_pid(p, PIDTYPE_TGID);
|
|
if (thread_group_leader(p)) {
|
|
detach_pid(p, PIDTYPE_PGID);
|
|
detach_pid(p, PIDTYPE_SID);
|
|
|
|
list_del_init(&p->tasks);
|
|
__get_cpu_var(process_counts)--;
|
|
}
|
|
|
|
remove_parent(p);
|
|
}
|
|
|
|
/*
|
|
* This function expects the tasklist_lock write-locked.
|
|
*/
|
|
static void __exit_signal(struct task_struct *tsk)
|
|
{
|
|
struct signal_struct *sig = tsk->signal;
|
|
struct sighand_struct *sighand;
|
|
|
|
BUG_ON(!sig);
|
|
BUG_ON(!atomic_read(&sig->count));
|
|
|
|
rcu_read_lock();
|
|
sighand = rcu_dereference(tsk->sighand);
|
|
spin_lock(&sighand->siglock);
|
|
|
|
posix_cpu_timers_exit(tsk);
|
|
if (atomic_dec_and_test(&sig->count))
|
|
posix_cpu_timers_exit_group(tsk);
|
|
else {
|
|
/*
|
|
* If there is any task waiting for the group exit
|
|
* then notify it:
|
|
*/
|
|
if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) {
|
|
wake_up_process(sig->group_exit_task);
|
|
sig->group_exit_task = NULL;
|
|
}
|
|
if (tsk == sig->curr_target)
|
|
sig->curr_target = next_thread(tsk);
|
|
/*
|
|
* Accumulate here the counters for all threads but the
|
|
* group leader as they die, so they can be added into
|
|
* the process-wide totals when those are taken.
|
|
* The group leader stays around as a zombie as long
|
|
* as there are other threads. When it gets reaped,
|
|
* the exit.c code will add its counts into these totals.
|
|
* We won't ever get here for the group leader, since it
|
|
* will have been the last reference on the signal_struct.
|
|
*/
|
|
sig->utime = cputime_add(sig->utime, tsk->utime);
|
|
sig->stime = cputime_add(sig->stime, tsk->stime);
|
|
sig->min_flt += tsk->min_flt;
|
|
sig->maj_flt += tsk->maj_flt;
|
|
sig->nvcsw += tsk->nvcsw;
|
|
sig->nivcsw += tsk->nivcsw;
|
|
sig->sched_time += tsk->sched_time;
|
|
sig = NULL; /* Marker for below. */
|
|
}
|
|
|
|
tsk->signal = NULL;
|
|
cleanup_sighand(tsk);
|
|
spin_unlock(&sighand->siglock);
|
|
rcu_read_unlock();
|
|
|
|
clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
|
|
flush_sigqueue(&tsk->pending);
|
|
if (sig) {
|
|
flush_sigqueue(&sig->shared_pending);
|
|
__cleanup_signal(sig);
|
|
}
|
|
}
|
|
|
|
void release_task(struct task_struct * p)
|
|
{
|
|
int zap_leader;
|
|
task_t *leader;
|
|
struct dentry *proc_dentry;
|
|
|
|
repeat:
|
|
atomic_dec(&p->user->processes);
|
|
spin_lock(&p->proc_lock);
|
|
proc_dentry = proc_pid_unhash(p);
|
|
write_lock_irq(&tasklist_lock);
|
|
ptrace_unlink(p);
|
|
BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
|
|
__exit_signal(p);
|
|
|
|
__unhash_process(p);
|
|
|
|
/*
|
|
* If we are the last non-leader member of the thread
|
|
* group, and the leader is zombie, then notify the
|
|
* group leader's parent process. (if it wants notification.)
|
|
*/
|
|
zap_leader = 0;
|
|
leader = p->group_leader;
|
|
if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
|
|
BUG_ON(leader->exit_signal == -1);
|
|
do_notify_parent(leader, leader->exit_signal);
|
|
/*
|
|
* If we were the last child thread and the leader has
|
|
* exited already, and the leader's parent ignores SIGCHLD,
|
|
* then we are the one who should release the leader.
|
|
*
|
|
* do_notify_parent() will have marked it self-reaping in
|
|
* that case.
|
|
*/
|
|
zap_leader = (leader->exit_signal == -1);
|
|
}
|
|
|
|
sched_exit(p);
|
|
write_unlock_irq(&tasklist_lock);
|
|
spin_unlock(&p->proc_lock);
|
|
proc_pid_flush(proc_dentry);
|
|
release_thread(p);
|
|
put_task_struct(p);
|
|
|
|
p = leader;
|
|
if (unlikely(zap_leader))
|
|
goto repeat;
|
|
}
|
|
|
|
/*
|
|
* 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 sid = -1;
|
|
|
|
read_lock(&tasklist_lock);
|
|
do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
|
|
if (p->signal->session > 0) {
|
|
sid = p->signal->session;
|
|
goto out;
|
|
}
|
|
} while_each_task_pid(pgrp, PIDTYPE_PGID, p);
|
|
p = find_task_by_pid(pgrp);
|
|
if (p)
|
|
sid = p->signal->session;
|
|
out:
|
|
read_unlock(&tasklist_lock);
|
|
|
|
return sid;
|
|
}
|
|
|
|
/*
|
|
* 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, task_t *ignored_task)
|
|
{
|
|
struct task_struct *p;
|
|
int ret = 1;
|
|
|
|
do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
|
|
if (p == ignored_task
|
|
|| p->exit_state
|
|
|| p->real_parent->pid == 1)
|
|
continue;
|
|
if (process_group(p->real_parent) != pgrp
|
|
&& p->real_parent->signal->session == p->signal->session) {
|
|
ret = 0;
|
|
break;
|
|
}
|
|
} while_each_task_pid(pgrp, PIDTYPE_PGID, p);
|
|
return ret; /* (sighing) "Often!" */
|
|
}
|
|
|
|
int is_orphaned_pgrp(int pgrp)
|
|
{
|
|
int retval;
|
|
|
|
read_lock(&tasklist_lock);
|
|
retval = will_become_orphaned_pgrp(pgrp, NULL);
|
|
read_unlock(&tasklist_lock);
|
|
|
|
return retval;
|
|
}
|
|
|
|
static int has_stopped_jobs(int pgrp)
|
|
{
|
|
int retval = 0;
|
|
struct task_struct *p;
|
|
|
|
do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
|
|
if (p->state != TASK_STOPPED)
|
|
continue;
|
|
|
|
/* If p is stopped by a debugger on a signal that won't
|
|
stop it, then don't count p as stopped. This isn't
|
|
perfect but it's a good approximation. */
|
|
if (unlikely (p->ptrace)
|
|
&& p->exit_code != SIGSTOP
|
|
&& p->exit_code != SIGTSTP
|
|
&& p->exit_code != SIGTTOU
|
|
&& p->exit_code != SIGTTIN)
|
|
continue;
|
|
|
|
retval = 1;
|
|
break;
|
|
} while_each_task_pid(pgrp, PIDTYPE_PGID, p);
|
|
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.
|
|
*/
|
|
static void reparent_to_init(void)
|
|
{
|
|
write_lock_irq(&tasklist_lock);
|
|
|
|
ptrace_unlink(current);
|
|
/* Reparent to init */
|
|
remove_parent(current);
|
|
current->parent = child_reaper;
|
|
current->real_parent = child_reaper;
|
|
add_parent(current);
|
|
|
|
/* Set the exit signal to SIGCHLD so we signal init on exit */
|
|
current->exit_signal = SIGCHLD;
|
|
|
|
if ((current->policy == SCHED_NORMAL ||
|
|
current->policy == SCHED_BATCH)
|
|
&& (task_nice(current) < 0))
|
|
set_user_nice(current, 0);
|
|
/* cpus_allowed? */
|
|
/* rt_priority? */
|
|
/* signals? */
|
|
security_task_reparent_to_init(current);
|
|
memcpy(current->signal->rlim, init_task.signal->rlim,
|
|
sizeof(current->signal->rlim));
|
|
atomic_inc(&(INIT_USER->__count));
|
|
write_unlock_irq(&tasklist_lock);
|
|
switch_uid(INIT_USER);
|
|
}
|
|
|
|
void __set_special_pids(pid_t session, pid_t pgrp)
|
|
{
|
|
struct task_struct *curr = current->group_leader;
|
|
|
|
if (curr->signal->session != session) {
|
|
detach_pid(curr, PIDTYPE_SID);
|
|
curr->signal->session = session;
|
|
attach_pid(curr, PIDTYPE_SID, session);
|
|
}
|
|
if (process_group(curr) != pgrp) {
|
|
detach_pid(curr, PIDTYPE_PGID);
|
|
curr->signal->pgrp = pgrp;
|
|
attach_pid(curr, PIDTYPE_PGID, pgrp);
|
|
}
|
|
}
|
|
|
|
void set_special_pids(pid_t session, pid_t pgrp)
|
|
{
|
|
write_lock_irq(&tasklist_lock);
|
|
__set_special_pids(session, pgrp);
|
|
write_unlock_irq(&tasklist_lock);
|
|
}
|
|
|
|
/*
|
|
* Let kernel threads use this to say that they
|
|
* allow a certain signal (since daemonize() will
|
|
* have disabled all of them by default).
|
|
*/
|
|
int allow_signal(int sig)
|
|
{
|
|
if (!valid_signal(sig) || sig < 1)
|
|
return -EINVAL;
|
|
|
|
spin_lock_irq(¤t->sighand->siglock);
|
|
sigdelset(¤t->blocked, sig);
|
|
if (!current->mm) {
|
|
/* Kernel threads handle their own signals.
|
|
Let the signal code know it'll be handled, so
|
|
that they don't get converted to SIGKILL or
|
|
just silently dropped */
|
|
current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
|
|
}
|
|
recalc_sigpending();
|
|
spin_unlock_irq(¤t->sighand->siglock);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(allow_signal);
|
|
|
|
int disallow_signal(int sig)
|
|
{
|
|
if (!valid_signal(sig) || sig < 1)
|
|
return -EINVAL;
|
|
|
|
spin_lock_irq(¤t->sighand->siglock);
|
|
sigaddset(¤t->blocked, sig);
|
|
recalc_sigpending();
|
|
spin_unlock_irq(¤t->sighand->siglock);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(disallow_signal);
|
|
|
|
/*
|
|
* Put all the gunge required to become a kernel thread without
|
|
* attached user resources in one place where it belongs.
|
|
*/
|
|
|
|
void daemonize(const char *name, ...)
|
|
{
|
|
va_list args;
|
|
struct fs_struct *fs;
|
|
sigset_t blocked;
|
|
|
|
va_start(args, name);
|
|
vsnprintf(current->comm, sizeof(current->comm), name, args);
|
|
va_end(args);
|
|
|
|
/*
|
|
* 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);
|
|
|
|
set_special_pids(1, 1);
|
|
mutex_lock(&tty_mutex);
|
|
current->signal->tty = NULL;
|
|
mutex_unlock(&tty_mutex);
|
|
|
|
/* Block and flush all signals */
|
|
sigfillset(&blocked);
|
|
sigprocmask(SIG_BLOCK, &blocked, NULL);
|
|
flush_signals(current);
|
|
|
|
/* 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_namespace(current);
|
|
current->namespace = init_task.namespace;
|
|
get_namespace(current->namespace);
|
|
exit_files(current);
|
|
current->files = init_task.files;
|
|
atomic_inc(¤t->files->count);
|
|
|
|
reparent_to_init();
|
|
}
|
|
|
|
EXPORT_SYMBOL(daemonize);
|
|
|
|
static void close_files(struct files_struct * files)
|
|
{
|
|
int i, j;
|
|
struct fdtable *fdt;
|
|
|
|
j = 0;
|
|
|
|
/*
|
|
* It is safe to dereference the fd table without RCU or
|
|
* ->file_lock because this is the last reference to the
|
|
* files structure.
|
|
*/
|
|
fdt = files_fdtable(files);
|
|
for (;;) {
|
|
unsigned long set;
|
|
i = j * __NFDBITS;
|
|
if (i >= fdt->max_fdset || i >= fdt->max_fds)
|
|
break;
|
|
set = fdt->open_fds->fds_bits[j++];
|
|
while (set) {
|
|
if (set & 1) {
|
|
struct file * file = xchg(&fdt->fd[i], NULL);
|
|
if (file)
|
|
filp_close(file, files);
|
|
}
|
|
i++;
|
|
set >>= 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
struct files_struct *get_files_struct(struct task_struct *task)
|
|
{
|
|
struct files_struct *files;
|
|
|
|
task_lock(task);
|
|
files = task->files;
|
|
if (files)
|
|
atomic_inc(&files->count);
|
|
task_unlock(task);
|
|
|
|
return files;
|
|
}
|
|
|
|
void fastcall put_files_struct(struct files_struct *files)
|
|
{
|
|
struct fdtable *fdt;
|
|
|
|
if (atomic_dec_and_test(&files->count)) {
|
|
close_files(files);
|
|
/*
|
|
* Free the fd and fdset arrays if we expanded them.
|
|
* If the fdtable was embedded, pass files for freeing
|
|
* at the end of the RCU grace period. Otherwise,
|
|
* you can free files immediately.
|
|
*/
|
|
fdt = files_fdtable(files);
|
|
if (fdt == &files->fdtab)
|
|
fdt->free_files = files;
|
|
else
|
|
kmem_cache_free(files_cachep, files);
|
|
free_fdtable(fdt);
|
|
}
|
|
}
|
|
|
|
EXPORT_SYMBOL(put_files_struct);
|
|
|
|
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);
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(exit_fs);
|
|
|
|
/*
|
|
* Turn us into a lazy TLB process if we
|
|
* aren't already..
|
|
*/
|
|
static void exit_mm(struct task_struct * tsk)
|
|
{
|
|
struct mm_struct *mm = tsk->mm;
|
|
|
|
mm_release(tsk, mm);
|
|
if (!mm)
|
|
return;
|
|
/*
|
|
* Serialize with any possible pending coredump.
|
|
* We must hold mmap_sem around checking core_waiters
|
|
* and clearing tsk->mm. The core-inducing thread
|
|
* will increment core_waiters for each thread in the
|
|
* group with ->mm != NULL.
|
|
*/
|
|
down_read(&mm->mmap_sem);
|
|
if (mm->core_waiters) {
|
|
up_read(&mm->mmap_sem);
|
|
down_write(&mm->mmap_sem);
|
|
if (!--mm->core_waiters)
|
|
complete(mm->core_startup_done);
|
|
up_write(&mm->mmap_sem);
|
|
|
|
wait_for_completion(&mm->core_done);
|
|
down_read(&mm->mmap_sem);
|
|
}
|
|
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;
|
|
up_read(&mm->mmap_sem);
|
|
enter_lazy_tlb(mm, current);
|
|
task_unlock(tsk);
|
|
mmput(mm);
|
|
}
|
|
|
|
static inline void choose_new_parent(task_t *p, task_t *reaper)
|
|
{
|
|
/*
|
|
* Make sure we're not reparenting to ourselves and that
|
|
* the parent is not a zombie.
|
|
*/
|
|
BUG_ON(p == reaper || reaper->exit_state);
|
|
p->real_parent = reaper;
|
|
}
|
|
|
|
static void reparent_thread(task_t *p, task_t *father, int traced)
|
|
{
|
|
/* We don't want people slaying init. */
|
|
if (p->exit_signal != -1)
|
|
p->exit_signal = SIGCHLD;
|
|
|
|
if (p->pdeath_signal)
|
|
/* We already hold the tasklist_lock here. */
|
|
group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
|
|
|
|
/* Move the child from its dying parent to the new one. */
|
|
if (unlikely(traced)) {
|
|
/* Preserve ptrace links if someone else is tracing this child. */
|
|
list_del_init(&p->ptrace_list);
|
|
if (p->parent != p->real_parent)
|
|
list_add(&p->ptrace_list, &p->real_parent->ptrace_children);
|
|
} else {
|
|
/* If this child is being traced, then we're the one tracing it
|
|
* anyway, so let go of it.
|
|
*/
|
|
p->ptrace = 0;
|
|
remove_parent(p);
|
|
p->parent = p->real_parent;
|
|
add_parent(p);
|
|
|
|
/* If we'd notified the old parent about this child's death,
|
|
* also notify the new parent.
|
|
*/
|
|
if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
|
|
thread_group_empty(p))
|
|
do_notify_parent(p, p->exit_signal);
|
|
else if (p->state == TASK_TRACED) {
|
|
/*
|
|
* If it was at a trace stop, turn it into
|
|
* a normal stop since it's no longer being
|
|
* traced.
|
|
*/
|
|
ptrace_untrace(p);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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 ((process_group(p) != process_group(father)) &&
|
|
(p->signal->session == father->signal->session)) {
|
|
int pgrp = process_group(p);
|
|
|
|
if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) {
|
|
__kill_pg_info(SIGHUP, SEND_SIG_PRIV, pgrp);
|
|
__kill_pg_info(SIGCONT, SEND_SIG_PRIV, pgrp);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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 void forget_original_parent(struct task_struct * father,
|
|
struct list_head *to_release)
|
|
{
|
|
struct task_struct *p, *reaper = father;
|
|
struct list_head *_p, *_n;
|
|
|
|
do {
|
|
reaper = next_thread(reaper);
|
|
if (reaper == father) {
|
|
reaper = child_reaper;
|
|
break;
|
|
}
|
|
} while (reaper->exit_state);
|
|
|
|
/*
|
|
* There are only two places where our children can be:
|
|
*
|
|
* - in our child list
|
|
* - in our ptraced child list
|
|
*
|
|
* Search them and reparent children.
|
|
*/
|
|
list_for_each_safe(_p, _n, &father->children) {
|
|
int ptrace;
|
|
p = list_entry(_p,struct task_struct,sibling);
|
|
|
|
ptrace = p->ptrace;
|
|
|
|
/* if father isn't the real parent, then ptrace must be enabled */
|
|
BUG_ON(father != p->real_parent && !ptrace);
|
|
|
|
if (father == p->real_parent) {
|
|
/* reparent with a reaper, real father it's us */
|
|
choose_new_parent(p, reaper);
|
|
reparent_thread(p, father, 0);
|
|
} else {
|
|
/* reparent ptraced task to its real parent */
|
|
__ptrace_unlink (p);
|
|
if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
|
|
thread_group_empty(p))
|
|
do_notify_parent(p, p->exit_signal);
|
|
}
|
|
|
|
/*
|
|
* if the ptraced child is a zombie with exit_signal == -1
|
|
* we must collect it before we exit, or it will remain
|
|
* zombie forever since we prevented it from self-reap itself
|
|
* while it was being traced by us, to be able to see it in wait4.
|
|
*/
|
|
if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1))
|
|
list_add(&p->ptrace_list, to_release);
|
|
}
|
|
list_for_each_safe(_p, _n, &father->ptrace_children) {
|
|
p = list_entry(_p,struct task_struct,ptrace_list);
|
|
choose_new_parent(p, reaper);
|
|
reparent_thread(p, father, 1);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Send signals to all our closest relatives so that they know
|
|
* to properly mourn us..
|
|
*/
|
|
static void exit_notify(struct task_struct *tsk)
|
|
{
|
|
int state;
|
|
struct task_struct *t;
|
|
struct list_head ptrace_dead, *_p, *_n;
|
|
|
|
if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT)
|
|
&& !thread_group_empty(tsk)) {
|
|
/*
|
|
* This occurs when there was a race between our exit
|
|
* syscall and a group signal choosing us as the one to
|
|
* wake up. It could be that we are the only thread
|
|
* alerted to check for pending signals, but another thread
|
|
* should be woken now to take the signal since we will not.
|
|
* Now we'll wake all the threads in the group just to make
|
|
* sure someone gets all the pending signals.
|
|
*/
|
|
read_lock(&tasklist_lock);
|
|
spin_lock_irq(&tsk->sighand->siglock);
|
|
for (t = next_thread(tsk); t != tsk; t = next_thread(t))
|
|
if (!signal_pending(t) && !(t->flags & PF_EXITING)) {
|
|
recalc_sigpending_tsk(t);
|
|
if (signal_pending(t))
|
|
signal_wake_up(t, 0);
|
|
}
|
|
spin_unlock_irq(&tsk->sighand->siglock);
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
|
|
write_lock_irq(&tasklist_lock);
|
|
|
|
/*
|
|
* This 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)
|
|
*/
|
|
|
|
INIT_LIST_HEAD(&ptrace_dead);
|
|
forget_original_parent(tsk, &ptrace_dead);
|
|
BUG_ON(!list_empty(&tsk->children));
|
|
BUG_ON(!list_empty(&tsk->ptrace_children));
|
|
|
|
/*
|
|
* 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 = tsk->real_parent;
|
|
|
|
if ((process_group(t) != process_group(tsk)) &&
|
|
(t->signal->session == tsk->signal->session) &&
|
|
will_become_orphaned_pgrp(process_group(tsk), tsk) &&
|
|
has_stopped_jobs(process_group(tsk))) {
|
|
__kill_pg_info(SIGHUP, SEND_SIG_PRIV, process_group(tsk));
|
|
__kill_pg_info(SIGCONT, SEND_SIG_PRIV, process_group(tsk));
|
|
}
|
|
|
|
/* 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 (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 &&
|
|
( tsk->parent_exec_id != t->self_exec_id ||
|
|
tsk->self_exec_id != tsk->parent_exec_id)
|
|
&& !capable(CAP_KILL))
|
|
tsk->exit_signal = SIGCHLD;
|
|
|
|
|
|
/* If something other than our normal parent is ptracing us, then
|
|
* send it a SIGCHLD instead of honoring exit_signal. exit_signal
|
|
* only has special meaning to our real parent.
|
|
*/
|
|
if (tsk->exit_signal != -1 && thread_group_empty(tsk)) {
|
|
int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD;
|
|
do_notify_parent(tsk, signal);
|
|
} else if (tsk->ptrace) {
|
|
do_notify_parent(tsk, SIGCHLD);
|
|
}
|
|
|
|
state = EXIT_ZOMBIE;
|
|
if (tsk->exit_signal == -1 &&
|
|
(likely(tsk->ptrace == 0) ||
|
|
unlikely(tsk->parent->signal->flags & SIGNAL_GROUP_EXIT)))
|
|
state = EXIT_DEAD;
|
|
tsk->exit_state = state;
|
|
|
|
write_unlock_irq(&tasklist_lock);
|
|
|
|
list_for_each_safe(_p, _n, &ptrace_dead) {
|
|
list_del_init(_p);
|
|
t = list_entry(_p,struct task_struct,ptrace_list);
|
|
release_task(t);
|
|
}
|
|
|
|
/* If the process is dead, release it - nobody will wait for it */
|
|
if (state == EXIT_DEAD)
|
|
release_task(tsk);
|
|
}
|
|
|
|
fastcall NORET_TYPE void do_exit(long code)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
int group_dead;
|
|
|
|
profile_task_exit(tsk);
|
|
|
|
WARN_ON(atomic_read(&tsk->fs_excl));
|
|
|
|
if (unlikely(in_interrupt()))
|
|
panic("Aiee, killing interrupt handler!");
|
|
if (unlikely(!tsk->pid))
|
|
panic("Attempted to kill the idle task!");
|
|
if (unlikely(tsk == child_reaper))
|
|
panic("Attempted to kill init!");
|
|
|
|
if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
|
|
current->ptrace_message = code;
|
|
ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
|
|
}
|
|
|
|
/*
|
|
* We're taking recursive faults here in do_exit. Safest is to just
|
|
* leave this task alone and wait for reboot.
|
|
*/
|
|
if (unlikely(tsk->flags & PF_EXITING)) {
|
|
printk(KERN_ALERT
|
|
"Fixing recursive fault but reboot is needed!\n");
|
|
if (tsk->io_context)
|
|
exit_io_context();
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
schedule();
|
|
}
|
|
|
|
tsk->flags |= PF_EXITING;
|
|
|
|
/*
|
|
* Make sure we don't try to process any timer firings
|
|
* while we are already exiting.
|
|
*/
|
|
tsk->it_virt_expires = cputime_zero;
|
|
tsk->it_prof_expires = cputime_zero;
|
|
tsk->it_sched_expires = 0;
|
|
|
|
if (unlikely(in_atomic()))
|
|
printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
|
|
current->comm, current->pid,
|
|
preempt_count());
|
|
|
|
acct_update_integrals(tsk);
|
|
if (tsk->mm) {
|
|
update_hiwater_rss(tsk->mm);
|
|
update_hiwater_vm(tsk->mm);
|
|
}
|
|
group_dead = atomic_dec_and_test(&tsk->signal->live);
|
|
if (group_dead) {
|
|
hrtimer_cancel(&tsk->signal->real_timer);
|
|
exit_itimers(tsk->signal);
|
|
acct_process(code);
|
|
}
|
|
if (unlikely(tsk->robust_list))
|
|
exit_robust_list(tsk);
|
|
#ifdef CONFIG_COMPAT
|
|
if (unlikely(tsk->compat_robust_list))
|
|
compat_exit_robust_list(tsk);
|
|
#endif
|
|
exit_mm(tsk);
|
|
|
|
exit_sem(tsk);
|
|
__exit_files(tsk);
|
|
__exit_fs(tsk);
|
|
exit_namespace(tsk);
|
|
exit_thread();
|
|
cpuset_exit(tsk);
|
|
exit_keys(tsk);
|
|
|
|
if (group_dead && tsk->signal->leader)
|
|
disassociate_ctty(1);
|
|
|
|
module_put(task_thread_info(tsk)->exec_domain->module);
|
|
if (tsk->binfmt)
|
|
module_put(tsk->binfmt->module);
|
|
|
|
tsk->exit_code = code;
|
|
proc_exit_connector(tsk);
|
|
exit_notify(tsk);
|
|
#ifdef CONFIG_NUMA
|
|
mpol_free(tsk->mempolicy);
|
|
tsk->mempolicy = NULL;
|
|
#endif
|
|
/*
|
|
* If DEBUG_MUTEXES is on, make sure we are holding no locks:
|
|
*/
|
|
mutex_debug_check_no_locks_held(tsk);
|
|
|
|
if (tsk->io_context)
|
|
exit_io_context();
|
|
|
|
/* PF_DEAD causes final put_task_struct after we schedule. */
|
|
preempt_disable();
|
|
BUG_ON(tsk->flags & PF_DEAD);
|
|
tsk->flags |= PF_DEAD;
|
|
|
|
schedule();
|
|
BUG();
|
|
/* Avoid "noreturn function does return". */
|
|
for (;;) ;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(do_exit);
|
|
|
|
NORET_TYPE void complete_and_exit(struct completion *comp, long code)
|
|
{
|
|
if (comp)
|
|
complete(comp);
|
|
|
|
do_exit(code);
|
|
}
|
|
|
|
EXPORT_SYMBOL(complete_and_exit);
|
|
|
|
asmlinkage long sys_exit(int error_code)
|
|
{
|
|
do_exit((error_code&0xff)<<8);
|
|
}
|
|
|
|
task_t fastcall *next_thread(const task_t *p)
|
|
{
|
|
return pid_task(p->pids[PIDTYPE_TGID].pid_list.next, PIDTYPE_TGID);
|
|
}
|
|
|
|
EXPORT_SYMBOL(next_thread);
|
|
|
|
/*
|
|
* Take down every thread in the group. This is called by fatal signals
|
|
* as well as by sys_exit_group (below).
|
|
*/
|
|
NORET_TYPE void
|
|
do_group_exit(int exit_code)
|
|
{
|
|
BUG_ON(exit_code & 0x80); /* core dumps don't get here */
|
|
|
|
if (current->signal->flags & SIGNAL_GROUP_EXIT)
|
|
exit_code = current->signal->group_exit_code;
|
|
else if (!thread_group_empty(current)) {
|
|
struct signal_struct *const sig = current->signal;
|
|
struct sighand_struct *const sighand = current->sighand;
|
|
read_lock(&tasklist_lock);
|
|
spin_lock_irq(&sighand->siglock);
|
|
if (sig->flags & SIGNAL_GROUP_EXIT)
|
|
/* Another thread got here before we took the lock. */
|
|
exit_code = sig->group_exit_code;
|
|
else {
|
|
sig->group_exit_code = exit_code;
|
|
zap_other_threads(current);
|
|
}
|
|
spin_unlock_irq(&sighand->siglock);
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
|
|
do_exit(exit_code);
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
/*
|
|
* this kills every thread in the thread group. Note that any externally
|
|
* wait4()-ing process will get the correct exit code - even if this
|
|
* thread is not the thread group leader.
|
|
*/
|
|
asmlinkage void sys_exit_group(int error_code)
|
|
{
|
|
do_group_exit((error_code & 0xff) << 8);
|
|
}
|
|
|
|
static int eligible_child(pid_t pid, int options, task_t *p)
|
|
{
|
|
if (pid > 0) {
|
|
if (p->pid != pid)
|
|
return 0;
|
|
} else if (!pid) {
|
|
if (process_group(p) != process_group(current))
|
|
return 0;
|
|
} else if (pid != -1) {
|
|
if (process_group(p) != -pid)
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Do not consider detached threads that are
|
|
* not ptraced:
|
|
*/
|
|
if (p->exit_signal == -1 && !p->ptrace)
|
|
return 0;
|
|
|
|
/* 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))
|
|
return 0;
|
|
/*
|
|
* Do not consider thread group leaders that are
|
|
* in a non-empty thread group:
|
|
*/
|
|
if (current->tgid != p->tgid && delay_group_leader(p))
|
|
return 2;
|
|
|
|
if (security_task_wait(p))
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int wait_noreap_copyout(task_t *p, pid_t pid, uid_t uid,
|
|
int why, int status,
|
|
struct siginfo __user *infop,
|
|
struct rusage __user *rusagep)
|
|
{
|
|
int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
|
|
put_task_struct(p);
|
|
if (!retval)
|
|
retval = put_user(SIGCHLD, &infop->si_signo);
|
|
if (!retval)
|
|
retval = put_user(0, &infop->si_errno);
|
|
if (!retval)
|
|
retval = put_user((short)why, &infop->si_code);
|
|
if (!retval)
|
|
retval = put_user(pid, &infop->si_pid);
|
|
if (!retval)
|
|
retval = put_user(uid, &infop->si_uid);
|
|
if (!retval)
|
|
retval = put_user(status, &infop->si_status);
|
|
if (!retval)
|
|
retval = pid;
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
|
|
* read_lock(&tasklist_lock) on entry. If we return zero, we still hold
|
|
* the lock and this task is uninteresting. If we return nonzero, we have
|
|
* released the lock and the system call should return.
|
|
*/
|
|
static int wait_task_zombie(task_t *p, int noreap,
|
|
struct siginfo __user *infop,
|
|
int __user *stat_addr, struct rusage __user *ru)
|
|
{
|
|
unsigned long state;
|
|
int retval;
|
|
int status;
|
|
|
|
if (unlikely(noreap)) {
|
|
pid_t pid = p->pid;
|
|
uid_t uid = p->uid;
|
|
int exit_code = p->exit_code;
|
|
int why, status;
|
|
|
|
if (unlikely(p->exit_state != EXIT_ZOMBIE))
|
|
return 0;
|
|
if (unlikely(p->exit_signal == -1 && p->ptrace == 0))
|
|
return 0;
|
|
get_task_struct(p);
|
|
read_unlock(&tasklist_lock);
|
|
if ((exit_code & 0x7f) == 0) {
|
|
why = CLD_EXITED;
|
|
status = exit_code >> 8;
|
|
} else {
|
|
why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
|
|
status = exit_code & 0x7f;
|
|
}
|
|
return wait_noreap_copyout(p, pid, uid, why,
|
|
status, infop, ru);
|
|
}
|
|
|
|
/*
|
|
* Try to move the task's state to DEAD
|
|
* only one thread is allowed to do this:
|
|
*/
|
|
state = xchg(&p->exit_state, EXIT_DEAD);
|
|
if (state != EXIT_ZOMBIE) {
|
|
BUG_ON(state != EXIT_DEAD);
|
|
return 0;
|
|
}
|
|
if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) {
|
|
/*
|
|
* This can only happen in a race with a ptraced thread
|
|
* dying on another processor.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
if (likely(p->real_parent == p->parent) && likely(p->signal)) {
|
|
struct signal_struct *psig;
|
|
struct signal_struct *sig;
|
|
|
|
/*
|
|
* The resource counters for the group leader are in its
|
|
* own task_struct. Those for dead threads in the group
|
|
* are in its signal_struct, as are those for the child
|
|
* processes it has previously reaped. All these
|
|
* accumulate in the parent's signal_struct c* fields.
|
|
*
|
|
* We don't bother to take a lock here to protect these
|
|
* p->signal fields, because they are only touched by
|
|
* __exit_signal, which runs with tasklist_lock
|
|
* write-locked anyway, and so is excluded here. We do
|
|
* need to protect the access to p->parent->signal fields,
|
|
* as other threads in the parent group can be right
|
|
* here reaping other children at the same time.
|
|
*/
|
|
spin_lock_irq(&p->parent->sighand->siglock);
|
|
psig = p->parent->signal;
|
|
sig = p->signal;
|
|
psig->cutime =
|
|
cputime_add(psig->cutime,
|
|
cputime_add(p->utime,
|
|
cputime_add(sig->utime,
|
|
sig->cutime)));
|
|
psig->cstime =
|
|
cputime_add(psig->cstime,
|
|
cputime_add(p->stime,
|
|
cputime_add(sig->stime,
|
|
sig->cstime)));
|
|
psig->cmin_flt +=
|
|
p->min_flt + sig->min_flt + sig->cmin_flt;
|
|
psig->cmaj_flt +=
|
|
p->maj_flt + sig->maj_flt + sig->cmaj_flt;
|
|
psig->cnvcsw +=
|
|
p->nvcsw + sig->nvcsw + sig->cnvcsw;
|
|
psig->cnivcsw +=
|
|
p->nivcsw + sig->nivcsw + sig->cnivcsw;
|
|
spin_unlock_irq(&p->parent->sighand->siglock);
|
|
}
|
|
|
|
/*
|
|
* Now we are sure this task is interesting, and no other
|
|
* thread can reap it because we set its state to EXIT_DEAD.
|
|
*/
|
|
read_unlock(&tasklist_lock);
|
|
|
|
retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
|
|
status = (p->signal->flags & SIGNAL_GROUP_EXIT)
|
|
? p->signal->group_exit_code : p->exit_code;
|
|
if (!retval && stat_addr)
|
|
retval = put_user(status, stat_addr);
|
|
if (!retval && infop)
|
|
retval = put_user(SIGCHLD, &infop->si_signo);
|
|
if (!retval && infop)
|
|
retval = put_user(0, &infop->si_errno);
|
|
if (!retval && infop) {
|
|
int why;
|
|
|
|
if ((status & 0x7f) == 0) {
|
|
why = CLD_EXITED;
|
|
status >>= 8;
|
|
} else {
|
|
why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
|
|
status &= 0x7f;
|
|
}
|
|
retval = put_user((short)why, &infop->si_code);
|
|
if (!retval)
|
|
retval = put_user(status, &infop->si_status);
|
|
}
|
|
if (!retval && infop)
|
|
retval = put_user(p->pid, &infop->si_pid);
|
|
if (!retval && infop)
|
|
retval = put_user(p->uid, &infop->si_uid);
|
|
if (retval) {
|
|
// TODO: is this safe?
|
|
p->exit_state = EXIT_ZOMBIE;
|
|
return retval;
|
|
}
|
|
retval = p->pid;
|
|
if (p->real_parent != p->parent) {
|
|
write_lock_irq(&tasklist_lock);
|
|
/* Double-check with lock held. */
|
|
if (p->real_parent != p->parent) {
|
|
__ptrace_unlink(p);
|
|
// TODO: is this safe?
|
|
p->exit_state = EXIT_ZOMBIE;
|
|
/*
|
|
* If this is not a detached task, notify the parent.
|
|
* If it's still not detached after that, don't release
|
|
* it now.
|
|
*/
|
|
if (p->exit_signal != -1) {
|
|
do_notify_parent(p, p->exit_signal);
|
|
if (p->exit_signal != -1)
|
|
p = NULL;
|
|
}
|
|
}
|
|
write_unlock_irq(&tasklist_lock);
|
|
}
|
|
if (p != NULL)
|
|
release_task(p);
|
|
BUG_ON(!retval);
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
|
|
* read_lock(&tasklist_lock) on entry. If we return zero, we still hold
|
|
* the lock and this task is uninteresting. If we return nonzero, we have
|
|
* released the lock and the system call should return.
|
|
*/
|
|
static int wait_task_stopped(task_t *p, int delayed_group_leader, int noreap,
|
|
struct siginfo __user *infop,
|
|
int __user *stat_addr, struct rusage __user *ru)
|
|
{
|
|
int retval, exit_code;
|
|
|
|
if (!p->exit_code)
|
|
return 0;
|
|
if (delayed_group_leader && !(p->ptrace & PT_PTRACED) &&
|
|
p->signal && p->signal->group_stop_count > 0)
|
|
/*
|
|
* A group stop is in progress and this is the group leader.
|
|
* We won't report until all threads have stopped.
|
|
*/
|
|
return 0;
|
|
|
|
/*
|
|
* Now we are pretty sure this task is interesting.
|
|
* Make sure it doesn't get reaped out from under us while we
|
|
* give up the lock and then examine it below. We don't want to
|
|
* keep holding onto the tasklist_lock while we call getrusage and
|
|
* possibly take page faults for user memory.
|
|
*/
|
|
get_task_struct(p);
|
|
read_unlock(&tasklist_lock);
|
|
|
|
if (unlikely(noreap)) {
|
|
pid_t pid = p->pid;
|
|
uid_t uid = p->uid;
|
|
int why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED;
|
|
|
|
exit_code = p->exit_code;
|
|
if (unlikely(!exit_code) ||
|
|
unlikely(p->state & TASK_TRACED))
|
|
goto bail_ref;
|
|
return wait_noreap_copyout(p, pid, uid,
|
|
why, (exit_code << 8) | 0x7f,
|
|
infop, ru);
|
|
}
|
|
|
|
write_lock_irq(&tasklist_lock);
|
|
|
|
/*
|
|
* This uses xchg to be atomic with the thread resuming and setting
|
|
* it. It must also be done with the write lock held to prevent a
|
|
* race with the EXIT_ZOMBIE case.
|
|
*/
|
|
exit_code = xchg(&p->exit_code, 0);
|
|
if (unlikely(p->exit_state)) {
|
|
/*
|
|
* The task resumed and then died. Let the next iteration
|
|
* catch it in EXIT_ZOMBIE. Note that exit_code might
|
|
* already be zero here if it resumed and did _exit(0).
|
|
* The task itself is dead and won't touch exit_code again;
|
|
* other processors in this function are locked out.
|
|
*/
|
|
p->exit_code = exit_code;
|
|
exit_code = 0;
|
|
}
|
|
if (unlikely(exit_code == 0)) {
|
|
/*
|
|
* Another thread in this function got to it first, or it
|
|
* resumed, or it resumed and then died.
|
|
*/
|
|
write_unlock_irq(&tasklist_lock);
|
|
bail_ref:
|
|
put_task_struct(p);
|
|
/*
|
|
* We are returning to the wait loop without having successfully
|
|
* removed the process and having released the lock. We cannot
|
|
* continue, since the "p" task pointer is potentially stale.
|
|
*
|
|
* Return -EAGAIN, and do_wait() will restart the loop from the
|
|
* beginning. Do _not_ re-acquire the lock.
|
|
*/
|
|
return -EAGAIN;
|
|
}
|
|
|
|
/* move to end of parent's list to avoid starvation */
|
|
remove_parent(p);
|
|
add_parent(p);
|
|
|
|
write_unlock_irq(&tasklist_lock);
|
|
|
|
retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
|
|
if (!retval && stat_addr)
|
|
retval = put_user((exit_code << 8) | 0x7f, stat_addr);
|
|
if (!retval && infop)
|
|
retval = put_user(SIGCHLD, &infop->si_signo);
|
|
if (!retval && infop)
|
|
retval = put_user(0, &infop->si_errno);
|
|
if (!retval && infop)
|
|
retval = put_user((short)((p->ptrace & PT_PTRACED)
|
|
? CLD_TRAPPED : CLD_STOPPED),
|
|
&infop->si_code);
|
|
if (!retval && infop)
|
|
retval = put_user(exit_code, &infop->si_status);
|
|
if (!retval && infop)
|
|
retval = put_user(p->pid, &infop->si_pid);
|
|
if (!retval && infop)
|
|
retval = put_user(p->uid, &infop->si_uid);
|
|
if (!retval)
|
|
retval = p->pid;
|
|
put_task_struct(p);
|
|
|
|
BUG_ON(!retval);
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* Handle do_wait work for one task in a live, non-stopped state.
|
|
* read_lock(&tasklist_lock) on entry. If we return zero, we still hold
|
|
* the lock and this task is uninteresting. If we return nonzero, we have
|
|
* released the lock and the system call should return.
|
|
*/
|
|
static int wait_task_continued(task_t *p, int noreap,
|
|
struct siginfo __user *infop,
|
|
int __user *stat_addr, struct rusage __user *ru)
|
|
{
|
|
int retval;
|
|
pid_t pid;
|
|
uid_t uid;
|
|
|
|
if (unlikely(!p->signal))
|
|
return 0;
|
|
|
|
if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
|
|
return 0;
|
|
|
|
spin_lock_irq(&p->sighand->siglock);
|
|
/* Re-check with the lock held. */
|
|
if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
|
|
spin_unlock_irq(&p->sighand->siglock);
|
|
return 0;
|
|
}
|
|
if (!noreap)
|
|
p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
|
|
spin_unlock_irq(&p->sighand->siglock);
|
|
|
|
pid = p->pid;
|
|
uid = p->uid;
|
|
get_task_struct(p);
|
|
read_unlock(&tasklist_lock);
|
|
|
|
if (!infop) {
|
|
retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
|
|
put_task_struct(p);
|
|
if (!retval && stat_addr)
|
|
retval = put_user(0xffff, stat_addr);
|
|
if (!retval)
|
|
retval = p->pid;
|
|
} else {
|
|
retval = wait_noreap_copyout(p, pid, uid,
|
|
CLD_CONTINUED, SIGCONT,
|
|
infop, ru);
|
|
BUG_ON(retval == 0);
|
|
}
|
|
|
|
return retval;
|
|
}
|
|
|
|
|
|
static inline int my_ptrace_child(struct task_struct *p)
|
|
{
|
|
if (!(p->ptrace & PT_PTRACED))
|
|
return 0;
|
|
if (!(p->ptrace & PT_ATTACHED))
|
|
return 1;
|
|
/*
|
|
* This child was PTRACE_ATTACH'd. We should be seeing it only if
|
|
* we are the attacher. If we are the real parent, this is a race
|
|
* inside ptrace_attach. It is waiting for the tasklist_lock,
|
|
* which we have to switch the parent links, but has already set
|
|
* the flags in p->ptrace.
|
|
*/
|
|
return (p->parent != p->real_parent);
|
|
}
|
|
|
|
static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
|
|
int __user *stat_addr, struct rusage __user *ru)
|
|
{
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
struct task_struct *tsk;
|
|
int flag, retval;
|
|
|
|
add_wait_queue(¤t->signal->wait_chldexit,&wait);
|
|
repeat:
|
|
/*
|
|
* We will set this flag if we see any child that might later
|
|
* match our criteria, even if we are not able to reap it yet.
|
|
*/
|
|
flag = 0;
|
|
current->state = TASK_INTERRUPTIBLE;
|
|
read_lock(&tasklist_lock);
|
|
tsk = current;
|
|
do {
|
|
struct task_struct *p;
|
|
struct list_head *_p;
|
|
int ret;
|
|
|
|
list_for_each(_p,&tsk->children) {
|
|
p = list_entry(_p,struct task_struct,sibling);
|
|
|
|
ret = eligible_child(pid, options, p);
|
|
if (!ret)
|
|
continue;
|
|
|
|
switch (p->state) {
|
|
case TASK_TRACED:
|
|
/*
|
|
* When we hit the race with PTRACE_ATTACH,
|
|
* we will not report this child. But the
|
|
* race means it has not yet been moved to
|
|
* our ptrace_children list, so we need to
|
|
* set the flag here to avoid a spurious ECHILD
|
|
* when the race happens with the only child.
|
|
*/
|
|
flag = 1;
|
|
if (!my_ptrace_child(p))
|
|
continue;
|
|
/*FALLTHROUGH*/
|
|
case TASK_STOPPED:
|
|
/*
|
|
* It's stopped now, so it might later
|
|
* continue, exit, or stop again.
|
|
*/
|
|
flag = 1;
|
|
if (!(options & WUNTRACED) &&
|
|
!my_ptrace_child(p))
|
|
continue;
|
|
retval = wait_task_stopped(p, ret == 2,
|
|
(options & WNOWAIT),
|
|
infop,
|
|
stat_addr, ru);
|
|
if (retval == -EAGAIN)
|
|
goto repeat;
|
|
if (retval != 0) /* He released the lock. */
|
|
goto end;
|
|
break;
|
|
default:
|
|
// case EXIT_DEAD:
|
|
if (p->exit_state == EXIT_DEAD)
|
|
continue;
|
|
// case EXIT_ZOMBIE:
|
|
if (p->exit_state == EXIT_ZOMBIE) {
|
|
/*
|
|
* Eligible but we cannot release
|
|
* it yet:
|
|
*/
|
|
if (ret == 2)
|
|
goto check_continued;
|
|
if (!likely(options & WEXITED))
|
|
continue;
|
|
retval = wait_task_zombie(
|
|
p, (options & WNOWAIT),
|
|
infop, stat_addr, ru);
|
|
/* He released the lock. */
|
|
if (retval != 0)
|
|
goto end;
|
|
break;
|
|
}
|
|
check_continued:
|
|
/*
|
|
* It's running now, so it might later
|
|
* exit, stop, or stop and then continue.
|
|
*/
|
|
flag = 1;
|
|
if (!unlikely(options & WCONTINUED))
|
|
continue;
|
|
retval = wait_task_continued(
|
|
p, (options & WNOWAIT),
|
|
infop, stat_addr, ru);
|
|
if (retval != 0) /* He released the lock. */
|
|
goto end;
|
|
break;
|
|
}
|
|
}
|
|
if (!flag) {
|
|
list_for_each(_p, &tsk->ptrace_children) {
|
|
p = list_entry(_p, struct task_struct,
|
|
ptrace_list);
|
|
if (!eligible_child(pid, options, p))
|
|
continue;
|
|
flag = 1;
|
|
break;
|
|
}
|
|
}
|
|
if (options & __WNOTHREAD)
|
|
break;
|
|
tsk = next_thread(tsk);
|
|
if (tsk->signal != current->signal)
|
|
BUG();
|
|
} while (tsk != current);
|
|
|
|
read_unlock(&tasklist_lock);
|
|
if (flag) {
|
|
retval = 0;
|
|
if (options & WNOHANG)
|
|
goto end;
|
|
retval = -ERESTARTSYS;
|
|
if (signal_pending(current))
|
|
goto end;
|
|
schedule();
|
|
goto repeat;
|
|
}
|
|
retval = -ECHILD;
|
|
end:
|
|
current->state = TASK_RUNNING;
|
|
remove_wait_queue(¤t->signal->wait_chldexit,&wait);
|
|
if (infop) {
|
|
if (retval > 0)
|
|
retval = 0;
|
|
else {
|
|
/*
|
|
* For a WNOHANG return, clear out all the fields
|
|
* we would set so the user can easily tell the
|
|
* difference.
|
|
*/
|
|
if (!retval)
|
|
retval = put_user(0, &infop->si_signo);
|
|
if (!retval)
|
|
retval = put_user(0, &infop->si_errno);
|
|
if (!retval)
|
|
retval = put_user(0, &infop->si_code);
|
|
if (!retval)
|
|
retval = put_user(0, &infop->si_pid);
|
|
if (!retval)
|
|
retval = put_user(0, &infop->si_uid);
|
|
if (!retval)
|
|
retval = put_user(0, &infop->si_status);
|
|
}
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
asmlinkage long sys_waitid(int which, pid_t pid,
|
|
struct siginfo __user *infop, int options,
|
|
struct rusage __user *ru)
|
|
{
|
|
long ret;
|
|
|
|
if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
|
|
return -EINVAL;
|
|
if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
|
|
return -EINVAL;
|
|
|
|
switch (which) {
|
|
case P_ALL:
|
|
pid = -1;
|
|
break;
|
|
case P_PID:
|
|
if (pid <= 0)
|
|
return -EINVAL;
|
|
break;
|
|
case P_PGID:
|
|
if (pid <= 0)
|
|
return -EINVAL;
|
|
pid = -pid;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
ret = do_wait(pid, options, infop, NULL, ru);
|
|
|
|
/* avoid REGPARM breakage on x86: */
|
|
prevent_tail_call(ret);
|
|
return ret;
|
|
}
|
|
|
|
asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr,
|
|
int options, struct rusage __user *ru)
|
|
{
|
|
long ret;
|
|
|
|
if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
|
|
__WNOTHREAD|__WCLONE|__WALL))
|
|
return -EINVAL;
|
|
ret = do_wait(pid, options | WEXITED, NULL, stat_addr, ru);
|
|
|
|
/* avoid REGPARM breakage on x86: */
|
|
prevent_tail_call(ret);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_SYS_WAITPID
|
|
|
|
/*
|
|
* sys_waitpid() remains for compatibility. waitpid() should be
|
|
* implemented by calling sys_wait4() from libc.a.
|
|
*/
|
|
asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options)
|
|
{
|
|
return sys_wait4(pid, stat_addr, options, NULL);
|
|
}
|
|
|
|
#endif
|