diff options
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 1841 |
1 files changed, 1841 insertions, 0 deletions
diff --git a/kernel/exit.c b/kernel/exit.c new file mode 100644 index 0000000..10e393b --- /dev/null +++ b/kernel/exit.c @@ -0,0 +1,1841 @@ +/* + * linux/kernel/exit.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/capability.h> +#include <linux/completion.h> +#include <linux/personality.h> +#include <linux/tty.h> +#include <linux/mnt_namespace.h> +#include <linux/iocontext.h> +#include <linux/key.h> +#include <linux/security.h> +#include <linux/cpu.h> +#include <linux/acct.h> +#include <linux/tsacct_kern.h> +#include <linux/file.h> +#include <linux/fdtable.h> +#include <linux/binfmts.h> +#include <linux/nsproxy.h> +#include <linux/pid_namespace.h> +#include <linux/ptrace.h> +#include <linux/profile.h> +#include <linux/mount.h> +#include <linux/proc_fs.h> +#include <linux/kthread.h> +#include <linux/mempolicy.h> +#include <linux/taskstats_kern.h> +#include <linux/delayacct.h> +#include <linux/freezer.h> +#include <linux/cgroup.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/pipe_fs_i.h> +#include <linux/audit.h> /* for audit_free() */ +#include <linux/resource.h> +#include <linux/blkdev.h> +#include <linux/task_io_accounting_ops.h> +#include <linux/tracehook.h> +#include <trace/sched.h> + +#include <asm/uaccess.h> +#include <asm/unistd.h> +#include <asm/pgtable.h> +#include <asm/mmu_context.h> + +static void exit_mm(struct task_struct * tsk); + +static inline int task_detached(struct task_struct *p) +{ + return p->exit_signal == -1; +} + +static void __unhash_process(struct task_struct *p) +{ + nr_threads--; + detach_pid(p, PIDTYPE_PID); + if (thread_group_leader(p)) { + detach_pid(p, PIDTYPE_PGID); + detach_pid(p, PIDTYPE_SID); + + list_del_rcu(&p->tasks); + __get_cpu_var(process_counts)--; + } + list_del_rcu(&p->thread_group); + list_del_init(&p->sibling); +} + +/* + * 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)); + + 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); + + 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->gtime = cputime_add(sig->gtime, task_gtime(tsk)); + sig->min_flt += tsk->min_flt; + sig->maj_flt += tsk->maj_flt; + sig->nvcsw += tsk->nvcsw; + sig->nivcsw += tsk->nivcsw; + sig->inblock += task_io_get_inblock(tsk); + sig->oublock += task_io_get_oublock(tsk); + task_io_accounting_add(&sig->ioac, &tsk->ioac); + sig = NULL; /* Marker for below. */ + } + + __unhash_process(tsk); + + /* + * Do this under ->siglock, we can race with another thread + * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals. + */ + flush_sigqueue(&tsk->pending); + + tsk->signal = NULL; + tsk->sighand = NULL; + spin_unlock(&sighand->siglock); + + __cleanup_sighand(sighand); + clear_tsk_thread_flag(tsk,TIF_SIGPENDING); + if (sig) { + flush_sigqueue(&sig->shared_pending); + taskstats_tgid_free(sig); + /* + * Make sure ->signal can't go away under rq->lock, + * see account_group_exec_runtime(). + */ + task_rq_unlock_wait(tsk); + __cleanup_signal(sig); + } +} + +static void delayed_put_task_struct(struct rcu_head *rhp) +{ + struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); + + trace_sched_process_free(tsk); + put_task_struct(tsk); +} + + +void release_task(struct task_struct * p) +{ + struct task_struct *leader; + int zap_leader; +repeat: + tracehook_prepare_release_task(p); + atomic_dec(&p->user->processes); + proc_flush_task(p); + write_lock_irq(&tasklist_lock); + tracehook_finish_release_task(p); + __exit_signal(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(task_detached(leader)); + 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 = task_detached(leader); + + /* + * This maintains the invariant that release_task() + * only runs on a task in EXIT_DEAD, just for sanity. + */ + if (zap_leader) + leader->exit_state = EXIT_DEAD; + } + + write_unlock_irq(&tasklist_lock); + release_thread(p); + call_rcu(&p->rcu, delayed_put_task_struct); + + 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... + * + * The caller must hold rcu lock or the tasklist lock. + */ +struct pid *session_of_pgrp(struct pid *pgrp) +{ + struct task_struct *p; + struct pid *sid = NULL; + + p = pid_task(pgrp, PIDTYPE_PGID); + if (p == NULL) + p = pid_task(pgrp, PIDTYPE_PID); + if (p != NULL) + sid = task_session(p); + + 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(struct pid *pgrp, struct task_struct *ignored_task) +{ + struct task_struct *p; + + do_each_pid_task(pgrp, PIDTYPE_PGID, p) { + if ((p == ignored_task) || + (p->exit_state && thread_group_empty(p)) || + is_global_init(p->real_parent)) + continue; + + if (task_pgrp(p->real_parent) != pgrp && + task_session(p->real_parent) == task_session(p)) + return 0; + } while_each_pid_task(pgrp, PIDTYPE_PGID, p); + + return 1; +} + +int is_current_pgrp_orphaned(void) +{ + int retval; + + read_lock(&tasklist_lock); + retval = will_become_orphaned_pgrp(task_pgrp(current), NULL); + read_unlock(&tasklist_lock); + + return retval; +} + +static int has_stopped_jobs(struct pid *pgrp) +{ + int retval = 0; + struct task_struct *p; + + do_each_pid_task(pgrp, PIDTYPE_PGID, p) { + if (!task_is_stopped(p)) + continue; + retval = 1; + break; + } while_each_pid_task(pgrp, PIDTYPE_PGID, p); + return retval; +} + +/* + * 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) + */ +static void +kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) +{ + struct pid *pgrp = task_pgrp(tsk); + struct task_struct *ignored_task = tsk; + + if (!parent) + /* exit: our father is in a different pgrp than + * we are and we were the only connection outside. + */ + parent = tsk->real_parent; + else + /* reparent: our child is in a different pgrp than + * we are, and it was the only connection outside. + */ + ignored_task = NULL; + + if (task_pgrp(parent) != pgrp && + task_session(parent) == task_session(tsk) && + will_become_orphaned_pgrp(pgrp, ignored_task) && + has_stopped_jobs(pgrp)) { + __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp); + __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp); + } +} + +/** + * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd + * + * If a kernel thread is launched as a result of a system call, or if + * it ever exits, it should generally reparent itself to kthreadd so it + * isn't in the way of other processes and 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_kthreadd() gives the caller full capabilities. + */ +static void reparent_to_kthreadd(void) +{ + write_lock_irq(&tasklist_lock); + + ptrace_unlink(current); + /* Reparent to init */ + current->real_parent = current->parent = kthreadd_task; + list_move_tail(¤t->sibling, ¤t->real_parent->children); + + /* Set the exit signal to SIGCHLD so we signal init on exit */ + current->exit_signal = SIGCHLD; + + if (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(struct pid *pid) +{ + struct task_struct *curr = current->group_leader; + pid_t nr = pid_nr(pid); + + if (task_session(curr) != pid) { + change_pid(curr, PIDTYPE_SID, pid); + set_task_session(curr, nr); + } + if (task_pgrp(curr) != pid) { + change_pid(curr, PIDTYPE_PGID, pid); + set_task_pgrp(curr, nr); + } +} + +static void set_special_pids(struct pid *pid) +{ + write_lock_irq(&tasklist_lock); + __set_special_pids(pid); + 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); + current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; + 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); + /* + * We don't want to have TIF_FREEZE set if the system-wide hibernation + * or suspend transition begins right now. + */ + current->flags |= (PF_NOFREEZE | PF_KTHREAD); + + if (current->nsproxy != &init_nsproxy) { + get_nsproxy(&init_nsproxy); + switch_task_namespaces(current, &init_nsproxy); + } + set_special_pids(&init_struct_pid); + proc_clear_tty(current); + + /* 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_files(current); + current->files = init_task.files; + atomic_inc(¤t->files->count); + + reparent_to_kthreadd(); +} + +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_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); + cond_resched(); + } + } + 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 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) + kmem_cache_free(files_cachep, files); + free_fdtable(fdt); + } +} + +void reset_files_struct(struct files_struct *files) +{ + struct task_struct *tsk = current; + struct files_struct *old; + + old = tsk->files; + task_lock(tsk); + tsk->files = files; + task_unlock(tsk); + put_files_struct(old); +} + +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 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)) { + path_put(&fs->root); + path_put(&fs->pwd); + kmem_cache_free(fs_cachep, fs); + } +} + +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); + } +} + +EXPORT_SYMBOL_GPL(exit_fs); + +#ifdef CONFIG_MM_OWNER +/* + * Task p is exiting and it owned mm, lets find a new owner for it + */ +static inline int +mm_need_new_owner(struct mm_struct *mm, struct task_struct *p) +{ + /* + * If there are other users of the mm and the owner (us) is exiting + * we need to find a new owner to take on the responsibility. + */ + if (atomic_read(&mm->mm_users) <= 1) + return 0; + if (mm->owner != p) + return 0; + return 1; +} + +void mm_update_next_owner(struct mm_struct *mm) +{ + struct task_struct *c, *g, *p = current; + +retry: + if (!mm_need_new_owner(mm, p)) + return; + + read_lock(&tasklist_lock); + /* + * Search in the children + */ + list_for_each_entry(c, &p->children, sibling) { + if (c->mm == mm) + goto assign_new_owner; + } + + /* + * Search in the siblings + */ + list_for_each_entry(c, &p->parent->children, sibling) { + if (c->mm == mm) + goto assign_new_owner; + } + + /* + * Search through everything else. We should not get + * here often + */ + do_each_thread(g, c) { + if (c->mm == mm) + goto assign_new_owner; + } while_each_thread(g, c); + + read_unlock(&tasklist_lock); + /* + * We found no owner yet mm_users > 1: this implies that we are + * most likely racing with swapoff (try_to_unuse()) or /proc or + * ptrace or page migration (get_task_mm()). Mark owner as NULL, + * so that subsystems can understand the callback and take action. + */ + down_write(&mm->mmap_sem); + cgroup_mm_owner_callbacks(mm->owner, NULL); + mm->owner = NULL; + up_write(&mm->mmap_sem); + return; + +assign_new_owner: + BUG_ON(c == p); + get_task_struct(c); + read_unlock(&tasklist_lock); + down_write(&mm->mmap_sem); + /* + * The task_lock protects c->mm from changing. + * We always want mm->owner->mm == mm + */ + task_lock(c); + if (c->mm != mm) { + task_unlock(c); + up_write(&mm->mmap_sem); + put_task_struct(c); + goto retry; + } + cgroup_mm_owner_callbacks(mm->owner, c); + mm->owner = c; + task_unlock(c); + up_write(&mm->mmap_sem); + put_task_struct(c); +} +#endif /* CONFIG_MM_OWNER */ + +/* + * 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; + struct core_state *core_state; + + mm_release(tsk, mm); + if (!mm) + return; + /* + * Serialize with any possible pending coredump. + * We must hold mmap_sem around checking core_state + * and clearing tsk->mm. The core-inducing thread + * will increment ->nr_threads for each thread in the + * group with ->mm != NULL. + */ + down_read(&mm->mmap_sem); + core_state = mm->core_state; + if (core_state) { + struct core_thread self; + up_read(&mm->mmap_sem); + + self.task = tsk; + self.next = xchg(&core_state->dumper.next, &self); + /* + * Implies mb(), the result of xchg() must be visible + * to core_state->dumper. + */ + if (atomic_dec_and_test(&core_state->nr_threads)) + complete(&core_state->startup); + + for (;;) { + set_task_state(tsk, TASK_UNINTERRUPTIBLE); + if (!self.task) /* see coredump_finish() */ + break; + schedule(); + } + __set_task_state(tsk, TASK_RUNNING); + down_read(&mm->mmap_sem); + } + atomic_inc(&mm->mm_count); + BUG_ON(mm != tsk->active_mm); + /* more a memory barrier than a real lock */ + task_lock(tsk); + tsk->mm = NULL; + up_read(&mm->mmap_sem); + enter_lazy_tlb(mm, current); + /* We don't want this task to be frozen prematurely */ + clear_freeze_flag(tsk); + task_unlock(tsk); + mm_update_next_owner(mm); + mmput(mm); +} + +/* + * Return nonzero if @parent's children should reap themselves. + * + * Called with write_lock_irq(&tasklist_lock) held. + */ +static int ignoring_children(struct task_struct *parent) +{ + int ret; + struct sighand_struct *psig = parent->sighand; + unsigned long flags; + spin_lock_irqsave(&psig->siglock, flags); + ret = (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || + (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT)); + spin_unlock_irqrestore(&psig->siglock, flags); + return ret; +} + +/* + * Detach all tasks we were using ptrace on. + * Any that need to be release_task'd are put on the @dead list. + * + * Called with write_lock(&tasklist_lock) held. + */ +static void ptrace_exit(struct task_struct *parent, struct list_head *dead) +{ + struct task_struct *p, *n; + int ign = -1; + + list_for_each_entry_safe(p, n, &parent->ptraced, ptrace_entry) { + __ptrace_unlink(p); + + if (p->exit_state != EXIT_ZOMBIE) + continue; + + /* + * If it's a zombie, our attachedness prevented normal + * parent notification or self-reaping. Do notification + * now if it would have happened earlier. If it should + * reap itself, add it to the @dead list. We can't call + * release_task() here because we already hold tasklist_lock. + * + * If it's our own child, there is no notification to do. + * But if our normal children self-reap, then this child + * was prevented by ptrace and we must reap it now. + */ + if (!task_detached(p) && thread_group_empty(p)) { + if (!same_thread_group(p->real_parent, parent)) + do_notify_parent(p, p->exit_signal); + else { + if (ign < 0) + ign = ignoring_children(parent); + if (ign) + p->exit_signal = -1; + } + } + + if (task_detached(p)) { + /* + * Mark it as in the process of being reaped. + */ + p->exit_state = EXIT_DEAD; + list_add(&p->ptrace_entry, dead); + } + } +} + +/* + * Finish up exit-time ptrace cleanup. + * + * Called without locks. + */ +static void ptrace_exit_finish(struct task_struct *parent, + struct list_head *dead) +{ + struct task_struct *p, *n; + + BUG_ON(!list_empty(&parent->ptraced)); + + list_for_each_entry_safe(p, n, dead, ptrace_entry) { + list_del_init(&p->ptrace_entry); + release_task(p); + } +} + +static void reparent_thread(struct task_struct *p, struct task_struct *father) +{ + if (p->pdeath_signal) + /* We already hold the tasklist_lock here. */ + group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p); + + list_move_tail(&p->sibling, &p->real_parent->children); + + /* If this is a threaded reparent there is no need to + * notify anyone anything has happened. + */ + if (same_thread_group(p->real_parent, father)) + return; + + /* We don't want people slaying init. */ + if (!task_detached(p)) + p->exit_signal = SIGCHLD; + + /* If we'd notified the old parent about this child's death, + * also notify the new parent. + */ + if (!ptrace_reparented(p) && + p->exit_state == EXIT_ZOMBIE && + !task_detached(p) && thread_group_empty(p)) + do_notify_parent(p, p->exit_signal); + + kill_orphaned_pgrp(p, father); +} + +/* + * 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 child reaper process (ie "init") in our pid + * space. + */ +static struct task_struct *find_new_reaper(struct task_struct *father) +{ + struct pid_namespace *pid_ns = task_active_pid_ns(father); + struct task_struct *thread; + + thread = father; + while_each_thread(father, thread) { + if (thread->flags & PF_EXITING) + continue; + if (unlikely(pid_ns->child_reaper == father)) + pid_ns->child_reaper = thread; + return thread; + } + + if (unlikely(pid_ns->child_reaper == father)) { + write_unlock_irq(&tasklist_lock); + if (unlikely(pid_ns == &init_pid_ns)) + panic("Attempted to kill init!"); + + zap_pid_ns_processes(pid_ns); + write_lock_irq(&tasklist_lock); + /* + * We can not clear ->child_reaper or leave it alone. + * There may by stealth EXIT_DEAD tasks on ->children, + * forget_original_parent() must move them somewhere. + */ + pid_ns->child_reaper = init_pid_ns.child_reaper; + } + + return pid_ns->child_reaper; +} + +static void forget_original_parent(struct task_struct *father) +{ + struct task_struct *p, *n, *reaper; + LIST_HEAD(ptrace_dead); + + write_lock_irq(&tasklist_lock); + reaper = find_new_reaper(father); + /* + * First clean up ptrace if we were using it. + */ + ptrace_exit(father, &ptrace_dead); + + list_for_each_entry_safe(p, n, &father->children, sibling) { + p->real_parent = reaper; + if (p->parent == father) { + BUG_ON(p->ptrace); + p->parent = p->real_parent; + } + reparent_thread(p, father); + } + + write_unlock_irq(&tasklist_lock); + BUG_ON(!list_empty(&father->children)); + + ptrace_exit_finish(father, &ptrace_dead); +} + +/* + * Send signals to all our closest relatives so that they know + * to properly mourn us.. + */ +static void exit_notify(struct task_struct *tsk, int group_dead) +{ + int signal; + void *cookie; + + /* + * 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) + */ + forget_original_parent(tsk); + exit_task_namespaces(tsk); + + write_lock_irq(&tasklist_lock); + if (group_dead) + kill_orphaned_pgrp(tsk->group_leader, NULL); + + /* 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 && !task_detached(tsk) && + (tsk->parent_exec_id != tsk->real_parent->self_exec_id || + tsk->self_exec_id != tsk->parent_exec_id) && + !capable(CAP_KILL)) + tsk->exit_signal = SIGCHLD; + + signal = tracehook_notify_death(tsk, &cookie, group_dead); + if (signal >= 0) + signal = do_notify_parent(tsk, signal); + + tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE; + + /* mt-exec, de_thread() is waiting for us */ + if (thread_group_leader(tsk) && + tsk->signal->group_exit_task && + tsk->signal->notify_count < 0) + wake_up_process(tsk->signal->group_exit_task); + + write_unlock_irq(&tasklist_lock); + + tracehook_report_death(tsk, signal, cookie, group_dead); + + /* If the process is dead, release it - nobody will wait for it */ + if (signal == DEATH_REAP) + release_task(tsk); +} + +#ifdef CONFIG_DEBUG_STACK_USAGE +static void check_stack_usage(void) +{ + static DEFINE_SPINLOCK(low_water_lock); + static int lowest_to_date = THREAD_SIZE; + unsigned long *n = end_of_stack(current); + unsigned long free; + + while (*n == 0) + n++; + free = (unsigned long)n - (unsigned long)end_of_stack(current); + + if (free >= lowest_to_date) + return; + + spin_lock(&low_water_lock); + if (free < lowest_to_date) { + printk(KERN_WARNING "%s used greatest stack depth: %lu bytes " + "left\n", + current->comm, free); + lowest_to_date = free; + } + spin_unlock(&low_water_lock); +} +#else +static inline void check_stack_usage(void) {} +#endif + +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!"); + + tracehook_report_exit(&code); + + /* + * 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"); + /* + * We can do this unlocked here. The futex code uses + * this flag just to verify whether the pi state + * cleanup has been done or not. In the worst case it + * loops once more. We pretend that the cleanup was + * done as there is no way to return. Either the + * OWNER_DIED bit is set by now or we push the blocked + * task into the wait for ever nirwana as well. + */ + tsk->flags |= PF_EXITPIDONE; + if (tsk->io_context) + exit_io_context(); + set_current_state(TASK_UNINTERRUPTIBLE); + schedule(); + } + + exit_signals(tsk); /* sets PF_EXITING */ + /* + * tsk->flags are checked in the futex code to protect against + * an exiting task cleaning up the robust pi futexes. + */ + smp_mb(); + spin_unlock_wait(&tsk->pi_lock); + + if (unlikely(in_atomic())) + printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", + current->comm, task_pid_nr(current), + 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_collect(code, group_dead); + if (group_dead) + tty_audit_exit(); + if (unlikely(tsk->audit_context)) + audit_free(tsk); + + tsk->exit_code = code; + taskstats_exit(tsk, group_dead); + + exit_mm(tsk); + + if (group_dead) + acct_process(); + trace_sched_process_exit(tsk); + + exit_sem(tsk); + exit_files(tsk); + exit_fs(tsk); + check_stack_usage(); + exit_thread(); + cgroup_exit(tsk, 1); + 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); + + proc_exit_connector(tsk); + exit_notify(tsk, group_dead); +#ifdef CONFIG_NUMA + mpol_put(tsk->mempolicy); + tsk->mempolicy = NULL; +#endif +#ifdef CONFIG_FUTEX + /* + * This must happen late, after the PID is not + * hashed anymore: + */ + if (unlikely(!list_empty(&tsk->pi_state_list))) + exit_pi_state_list(tsk); + if (unlikely(current->pi_state_cache)) + kfree(current->pi_state_cache); +#endif + /* + * Make sure we are holding no locks: + */ + debug_check_no_locks_held(tsk); + /* + * We can do this unlocked here. The futex code uses this flag + * just to verify whether the pi state cleanup has been done + * or not. In the worst case it loops once more. + */ + tsk->flags |= PF_EXITPIDONE; + + if (tsk->io_context) + exit_io_context(); + + if (tsk->splice_pipe) + __free_pipe_info(tsk->splice_pipe); + + preempt_disable(); + /* causes final put_task_struct in finish_task_switch(). */ + tsk->state = TASK_DEAD; + + schedule(); + BUG(); + /* Avoid "noreturn function does return". */ + for (;;) + cpu_relax(); /* For when BUG is null */ +} + +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); + +SYSCALL_DEFINE1(exit, int, error_code) +{ + do_exit((error_code&0xff)<<8); +} + +/* + * 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) +{ + struct signal_struct *sig = current->signal; + + BUG_ON(exit_code & 0x80); /* core dumps don't get here */ + + if (signal_group_exit(sig)) + exit_code = sig->group_exit_code; + else if (!thread_group_empty(current)) { + struct sighand_struct *const sighand = current->sighand; + spin_lock_irq(&sighand->siglock); + if (signal_group_exit(sig)) + /* Another thread got here before we took the lock. */ + exit_code = sig->group_exit_code; + else { + sig->group_exit_code = exit_code; + sig->flags = SIGNAL_GROUP_EXIT; + zap_other_threads(current); + } + spin_unlock_irq(&sighand->siglock); + } + + 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. + */ +SYSCALL_DEFINE1(exit_group, int, error_code) +{ + do_group_exit((error_code & 0xff) << 8); + /* NOTREACHED */ + return 0; +} + +static struct pid *task_pid_type(struct task_struct *task, enum pid_type type) +{ + struct pid *pid = NULL; + if (type == PIDTYPE_PID) + pid = task->pids[type].pid; + else if (type < PIDTYPE_MAX) + pid = task->group_leader->pids[type].pid; + return pid; +} + +static int eligible_child(enum pid_type type, struct pid *pid, int options, + struct task_struct *p) +{ + int err; + + if (type < PIDTYPE_MAX) { + if (task_pid_type(p, type) != pid) + 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; + + err = security_task_wait(p); + if (err) + return err; + + return 1; +} + +static int wait_noreap_copyout(struct task_struct *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(struct task_struct *p, int options, + struct siginfo __user *infop, + int __user *stat_addr, struct rusage __user *ru) +{ + unsigned long state; + int retval, status, traced; + pid_t pid = task_pid_vnr(p); + + if (!likely(options & WEXITED)) + return 0; + + if (unlikely(options & WNOWAIT)) { + uid_t uid = p->uid; + int exit_code = p->exit_code; + int why, status; + + 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; + } + + traced = ptrace_reparented(p); + + if (likely(!traced)) { + struct signal_struct *psig; + struct signal_struct *sig; + struct task_cputime cputime; + + /* + * 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. + * + * We use thread_group_cputime() to get times for the thread + * group, which consolidates times for all threads in the + * group including the group leader. + */ + spin_lock_irq(&p->parent->sighand->siglock); + psig = p->parent->signal; + sig = p->signal; + thread_group_cputime(p, &cputime); + psig->cutime = + cputime_add(psig->cutime, + cputime_add(cputime.utime, + sig->cutime)); + psig->cstime = + cputime_add(psig->cstime, + cputime_add(cputime.stime, + sig->cstime)); + psig->cgtime = + cputime_add(psig->cgtime, + cputime_add(p->gtime, + cputime_add(sig->gtime, + sig->cgtime))); + 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; + psig->cinblock += + task_io_get_inblock(p) + + sig->inblock + sig->cinblock; + psig->coublock += + task_io_get_oublock(p) + + sig->oublock + sig->coublock; + task_io_accounting_add(&psig->ioac, &p->ioac); + task_io_accounting_add(&psig->ioac, &sig->ioac); + 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(pid, &infop->si_pid); + if (!retval && infop) + retval = put_user(p->uid, &infop->si_uid); + if (!retval) + retval = pid; + + if (traced) { + write_lock_irq(&tasklist_lock); + /* We dropped tasklist, ptracer could die and untrace */ + ptrace_unlink(p); + /* + * If this is not a detached task, notify the parent. + * If it's still not detached after that, don't release + * it now. + */ + if (!task_detached(p)) { + do_notify_parent(p, p->exit_signal); + if (!task_detached(p)) { + p->exit_state = EXIT_ZOMBIE; + p = NULL; + } + } + write_unlock_irq(&tasklist_lock); + } + if (p != NULL) + release_task(p); + + 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(int ptrace, struct task_struct *p, + int options, struct siginfo __user *infop, + int __user *stat_addr, struct rusage __user *ru) +{ + int retval, exit_code, why; + uid_t uid = 0; /* unneeded, required by compiler */ + pid_t pid; + + if (!(options & WUNTRACED)) + return 0; + + exit_code = 0; + spin_lock_irq(&p->sighand->siglock); + + if (unlikely(!task_is_stopped_or_traced(p))) + goto unlock_sig; + + if (!ptrace && 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. + */ + goto unlock_sig; + + exit_code = p->exit_code; + if (!exit_code) + goto unlock_sig; + + if (!unlikely(options & WNOWAIT)) + p->exit_code = 0; + + uid = p->uid; +unlock_sig: + spin_unlock_irq(&p->sighand->siglock); + if (!exit_code) + 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); + pid = task_pid_vnr(p); + why = ptrace ? CLD_TRAPPED : CLD_STOPPED; + read_unlock(&tasklist_lock); + + if (unlikely(options & WNOWAIT)) + return wait_noreap_copyout(p, pid, uid, + why, exit_code, + infop, ru); + + 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)why, &infop->si_code); + if (!retval && infop) + retval = put_user(exit_code, &infop->si_status); + if (!retval && infop) + retval = put_user(pid, &infop->si_pid); + if (!retval && infop) + retval = put_user(uid, &infop->si_uid); + if (!retval) + retval = 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(struct task_struct *p, int options, + struct siginfo __user *infop, + int __user *stat_addr, struct rusage __user *ru) +{ + int retval; + pid_t pid; + uid_t uid; + + if (!unlikely(options & WCONTINUED)) + 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 (!unlikely(options & WNOWAIT)) + p->signal->flags &= ~SIGNAL_STOP_CONTINUED; + spin_unlock_irq(&p->sighand->siglock); + + pid = task_pid_vnr(p); + 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 = pid; + } else { + retval = wait_noreap_copyout(p, pid, uid, + CLD_CONTINUED, SIGCONT, + infop, ru); + BUG_ON(retval == 0); + } + + return retval; +} + +/* + * Consider @p for a wait by @parent. + * + * -ECHILD should be in *@notask_error before the first call. + * Returns nonzero for a final return, when we have unlocked tasklist_lock. + * Returns zero if the search for a child should continue; + * then *@notask_error is 0 if @p is an eligible child, + * or another error from security_task_wait(), or still -ECHILD. + */ +static int wait_consider_task(struct task_struct *parent, int ptrace, + struct task_struct *p, int *notask_error, + enum pid_type type, struct pid *pid, int options, + struct siginfo __user *infop, + int __user *stat_addr, struct rusage __user *ru) +{ + int ret = eligible_child(type, pid, options, p); + if (!ret) + return ret; + + if (unlikely(ret < 0)) { + /* + * If we have not yet seen any eligible child, + * then let this error code replace -ECHILD. + * A permission error will give the user a clue + * to look for security policy problems, rather + * than for mysterious wait bugs. + */ + if (*notask_error) + *notask_error = ret; + } + + if (likely(!ptrace) && unlikely(p->ptrace)) { + /* + * This child is hidden by ptrace. + * We aren't allowed to see it now, but eventually we will. + */ + *notask_error = 0; + return 0; + } + + if (p->exit_state == EXIT_DEAD) + return 0; + + /* + * We don't reap group leaders with subthreads. + */ + if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p)) + return wait_task_zombie(p, options, infop, stat_addr, ru); + + /* + * It's stopped or running now, so it might + * later continue, exit, or stop again. + */ + *notask_error = 0; + + if (task_is_stopped_or_traced(p)) + return wait_task_stopped(ptrace, p, options, + infop, stat_addr, ru); + + return wait_task_continued(p, options, infop, stat_addr, ru); +} + +/* + * Do the work of do_wait() for one thread in the group, @tsk. + * + * -ECHILD should be in *@notask_error before the first call. + * Returns nonzero for a final return, when we have unlocked tasklist_lock. + * Returns zero if the search for a child should continue; then + * *@notask_error is 0 if there were any eligible children, + * or another error from security_task_wait(), or still -ECHILD. + */ +static int do_wait_thread(struct task_struct *tsk, int *notask_error, + enum pid_type type, struct pid *pid, int options, + struct siginfo __user *infop, int __user *stat_addr, + struct rusage __user *ru) +{ + struct task_struct *p; + + list_for_each_entry(p, &tsk->children, sibling) { + /* + * Do not consider detached threads. + */ + if (!task_detached(p)) { + int ret = wait_consider_task(tsk, 0, p, notask_error, + type, pid, options, + infop, stat_addr, ru); + if (ret) + return ret; + } + } + + return 0; +} + +static int ptrace_do_wait(struct task_struct *tsk, int *notask_error, + enum pid_type type, struct pid *pid, int options, + struct siginfo __user *infop, int __user *stat_addr, + struct rusage __user *ru) +{ + struct task_struct *p; + + /* + * Traditionally we see ptrace'd stopped tasks regardless of options. + */ + options |= WUNTRACED; + + list_for_each_entry(p, &tsk->ptraced, ptrace_entry) { + int ret = wait_consider_task(tsk, 1, p, notask_error, + type, pid, options, + infop, stat_addr, ru); + if (ret) + return ret; + } + + return 0; +} + +static long do_wait(enum pid_type type, struct pid *pid, int options, + struct siginfo __user *infop, int __user *stat_addr, + struct rusage __user *ru) +{ + DECLARE_WAITQUEUE(wait, current); + struct task_struct *tsk; + int retval; + + trace_sched_process_wait(pid); + + add_wait_queue(¤t->signal->wait_chldexit,&wait); +repeat: + /* + * If there is nothing that can match our critiera just get out. + * We will clear @retval to zero if we see any child that might later + * match our criteria, even if we are not able to reap it yet. + */ + retval = -ECHILD; + if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type]))) + goto end; + + current->state = TASK_INTERRUPTIBLE; + read_lock(&tasklist_lock); + tsk = current; + do { + int tsk_result = do_wait_thread(tsk, &retval, + type, pid, options, + infop, stat_addr, ru); + if (!tsk_result) + tsk_result = ptrace_do_wait(tsk, &retval, + type, pid, options, + infop, stat_addr, ru); + if (tsk_result) { + /* + * tasklist_lock is unlocked and we have a final result. + */ + retval = tsk_result; + goto end; + } + + if (options & __WNOTHREAD) + break; + tsk = next_thread(tsk); + BUG_ON(tsk->signal != current->signal); + } while (tsk != current); + read_unlock(&tasklist_lock); + + if (!retval && !(options & WNOHANG)) { + retval = -ERESTARTSYS; + if (!signal_pending(current)) { + schedule(); + goto repeat; + } + } + +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; +} + +SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, + infop, int, options, struct rusage __user *, ru) +{ + struct pid *pid = NULL; + enum pid_type type; + long ret; + + if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED)) + return -EINVAL; + if (!(options & (WEXITED|WSTOPPED|WCONTINUED))) + return -EINVAL; + + switch (which) { + case P_ALL: + type = PIDTYPE_MAX; + break; + case P_PID: + type = PIDTYPE_PID; + if (upid <= 0) + return -EINVAL; + break; + case P_PGID: + type = PIDTYPE_PGID; + if (upid <= 0) + return -EINVAL; + break; + default: + return -EINVAL; + } + + if (type < PIDTYPE_MAX) + pid = find_get_pid(upid); + ret = do_wait(type, pid, options, infop, NULL, ru); + put_pid(pid); + + /* avoid REGPARM breakage on x86: */ + asmlinkage_protect(5, ret, which, upid, infop, options, ru); + return ret; +} + +SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr, + int, options, struct rusage __user *, ru) +{ + struct pid *pid = NULL; + enum pid_type type; + long ret; + + if (options & ~(WNOHANG|WUNTRACED|WCONTINUED| + __WNOTHREAD|__WCLONE|__WALL)) + return -EINVAL; + + if (upid == -1) + type = PIDTYPE_MAX; + else if (upid < 0) { + type = PIDTYPE_PGID; + pid = find_get_pid(-upid); + } else if (upid == 0) { + type = PIDTYPE_PGID; + pid = get_pid(task_pgrp(current)); + } else /* upid > 0 */ { + type = PIDTYPE_PID; + pid = find_get_pid(upid); + } + + ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru); + put_pid(pid); + + /* avoid REGPARM breakage on x86: */ + asmlinkage_protect(4, ret, upid, stat_addr, options, ru); + return ret; +} + +#ifdef __ARCH_WANT_SYS_WAITPID + +/* + * sys_waitpid() remains for compatibility. waitpid() should be + * implemented by calling sys_wait4() from libc.a. + */ +SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options) +{ + return sys_wait4(pid, stat_addr, options, NULL); +} + +#endif |
