blob: 7a831142293063e88a25c3d1886d3f375f03b6f4 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/kernel/exit.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#include <linux/mm.h>
8#include <linux/slab.h>
9#include <linux/interrupt.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/module.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080011#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/completion.h>
13#include <linux/personality.h>
14#include <linux/tty.h>
Kirill Korotaev6b3286e2006-12-08 02:37:56 -080015#include <linux/mnt_namespace.h>
Jens Axboeda9cbc82008-06-30 20:42:08 +020016#include <linux/iocontext.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/key.h>
18#include <linux/security.h>
19#include <linux/cpu.h>
20#include <linux/acct.h>
Jay Lan8f0ab512006-09-30 23:28:59 -070021#include <linux/tsacct_kern.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/file.h>
Al Viro9f3acc32008-04-24 07:44:08 -040023#include <linux/fdtable.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <linux/binfmts.h>
Serge E. Hallynab516012006-10-02 02:18:06 -070025#include <linux/nsproxy.h>
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -080026#include <linux/pid_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/ptrace.h>
28#include <linux/profile.h>
29#include <linux/mount.h>
30#include <linux/proc_fs.h>
Eric W. Biederman49d769d2007-05-09 02:34:33 -070031#include <linux/kthread.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <linux/mempolicy.h>
Shailabh Nagarc7572492006-07-14 00:24:40 -070033#include <linux/taskstats_kern.h>
Shailabh Nagarca74e922006-07-14 00:24:36 -070034#include <linux/delayacct.h>
Rafael J. Wysocki83144182007-07-17 04:03:35 -070035#include <linux/freezer.h>
Paul Menageb4f48b62007-10-18 23:39:33 -070036#include <linux/cgroup.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070037#include <linux/syscalls.h>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070038#include <linux/signal.h>
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -080039#include <linux/posix-timers.h>
Matt Helsley9f460802005-11-07 00:59:16 -080040#include <linux/cn_proc.h>
Ingo Molnarde5097c2006-01-09 15:59:21 -080041#include <linux/mutex.h>
Ingo Molnar0771dfe2006-03-27 01:16:22 -080042#include <linux/futex.h>
Jens Axboeb92ce552006-04-11 13:52:07 +020043#include <linux/pipe_fs_i.h>
Al Virofa84cb92006-03-29 20:30:19 -050044#include <linux/audit.h> /* for audit_free() */
Adrian Bunk83cc5ed2006-06-25 05:47:41 -070045#include <linux/resource.h>
David Howells0d67a462006-08-29 19:05:56 +010046#include <linux/blkdev.h>
Eric Dumazet6eaeeab2007-05-10 22:22:37 -070047#include <linux/task_io_accounting_ops.h>
Roland McGrath30199f52008-07-25 19:45:46 -070048#include <linux/tracehook.h>
David Howellsd84f4f92008-11-14 10:39:23 +110049#include <linux/init_task.h>
Mathieu Desnoyers0a16b602008-07-18 12:16:17 -040050#include <trace/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070051
52#include <asm/uaccess.h>
53#include <asm/unistd.h>
54#include <asm/pgtable.h>
55#include <asm/mmu_context.h>
David Howellsd84f4f92008-11-14 10:39:23 +110056#include "cred-internals.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -050058DEFINE_TRACE(sched_process_free);
59DEFINE_TRACE(sched_process_exit);
60DEFINE_TRACE(sched_process_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
Adrian Bunk408b6642005-05-01 08:59:29 -070062static void exit_mm(struct task_struct * tsk);
63
Oleg Nesterovd839fd42008-04-30 00:53:11 -070064static inline int task_detached(struct task_struct *p)
65{
66 return p->exit_signal == -1;
67}
68
Linus Torvalds1da177e2005-04-16 15:20:36 -070069static void __unhash_process(struct task_struct *p)
70{
71 nr_threads--;
72 detach_pid(p, PIDTYPE_PID);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 if (thread_group_leader(p)) {
74 detach_pid(p, PIDTYPE_PGID);
75 detach_pid(p, PIDTYPE_SID);
Oleg Nesterovc97d9892006-03-28 16:11:06 -080076
Eric W. Biederman5e85d4a2006-04-18 22:20:16 -070077 list_del_rcu(&p->tasks);
Oleg Nesterov73b9ebf2006-03-28 16:11:07 -080078 __get_cpu_var(process_counts)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 }
Oleg Nesterov47e65322006-03-28 16:11:25 -080080 list_del_rcu(&p->thread_group);
Roland McGrathf4700212008-03-24 18:36:23 -070081 list_del_init(&p->sibling);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082}
83
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -080084/*
85 * This function expects the tasklist_lock write-locked.
86 */
87static void __exit_signal(struct task_struct *tsk)
88{
89 struct signal_struct *sig = tsk->signal;
90 struct sighand_struct *sighand;
91
92 BUG_ON(!sig);
93 BUG_ON(!atomic_read(&sig->count));
94
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -080095 sighand = rcu_dereference(tsk->sighand);
96 spin_lock(&sighand->siglock);
97
98 posix_cpu_timers_exit(tsk);
99 if (atomic_dec_and_test(&sig->count))
100 posix_cpu_timers_exit_group(tsk);
101 else {
102 /*
103 * If there is any task waiting for the group exit
104 * then notify it:
105 */
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700106 if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count)
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800107 wake_up_process(sig->group_exit_task);
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700108
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800109 if (tsk == sig->curr_target)
110 sig->curr_target = next_thread(tsk);
111 /*
112 * Accumulate here the counters for all threads but the
113 * group leader as they die, so they can be added into
114 * the process-wide totals when those are taken.
115 * The group leader stays around as a zombie as long
116 * as there are other threads. When it gets reaped,
117 * the exit.c code will add its counts into these totals.
118 * We won't ever get here for the group leader, since it
119 * will have been the last reference on the signal_struct.
120 */
Peter Zijlstra32bd6712009-02-05 12:24:15 +0100121 sig->utime = cputime_add(sig->utime, task_utime(tsk));
122 sig->stime = cputime_add(sig->stime, task_stime(tsk));
Balbir Singh49048622008-09-05 18:12:23 +0200123 sig->gtime = cputime_add(sig->gtime, task_gtime(tsk));
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800124 sig->min_flt += tsk->min_flt;
125 sig->maj_flt += tsk->maj_flt;
126 sig->nvcsw += tsk->nvcsw;
127 sig->nivcsw += tsk->nivcsw;
Eric Dumazet6eaeeab2007-05-10 22:22:37 -0700128 sig->inblock += task_io_get_inblock(tsk);
129 sig->oublock += task_io_get_oublock(tsk);
Andrea Righi59954772008-07-27 17:29:15 +0200130 task_io_accounting_add(&sig->ioac, &tsk->ioac);
Peter Zijlstra32bd6712009-02-05 12:24:15 +0100131 sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800132 sig = NULL; /* Marker for below. */
133 }
134
Oleg Nesterov58767002006-03-28 16:11:20 -0800135 __unhash_process(tsk);
136
Oleg Nesterovda7978b2008-05-23 13:04:41 -0700137 /*
138 * Do this under ->siglock, we can race with another thread
139 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
140 */
141 flush_sigqueue(&tsk->pending);
142
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800143 tsk->signal = NULL;
Oleg Nesterova7e53282006-03-28 16:11:27 -0800144 tsk->sighand = NULL;
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800145 spin_unlock(&sighand->siglock);
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800146
Oleg Nesterova7e53282006-03-28 16:11:27 -0800147 __cleanup_sighand(sighand);
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800148 clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800149 if (sig) {
150 flush_sigqueue(&sig->shared_pending);
Oleg Nesterov093a8e82006-10-28 10:38:51 -0700151 taskstats_tgid_free(sig);
Oleg Nesterovad474ca2008-11-10 15:39:30 +0100152 /*
153 * Make sure ->signal can't go away under rq->lock,
154 * see account_group_exec_runtime().
155 */
156 task_rq_unlock_wait(tsk);
Oleg Nesterov6a14c5c2006-03-28 16:11:18 -0800157 __cleanup_signal(sig);
158 }
159}
160
Eric W. Biederman8c7904a2006-03-31 02:31:37 -0800161static void delayed_put_task_struct(struct rcu_head *rhp)
162{
Mathieu Desnoyers0a16b602008-07-18 12:16:17 -0400163 struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
164
165 trace_sched_process_free(tsk);
166 put_task_struct(tsk);
Eric W. Biederman8c7904a2006-03-31 02:31:37 -0800167}
168
Roland McGrathf4700212008-03-24 18:36:23 -0700169
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170void release_task(struct task_struct * p)
171{
Ingo Molnar36c8b582006-07-03 00:25:41 -0700172 struct task_struct *leader;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 int zap_leader;
Oleg Nesterov1f09f972006-03-28 16:11:11 -0800174repeat:
Roland McGrathdae33572008-07-25 19:45:48 -0700175 tracehook_prepare_release_task(p);
David Howellsc69e8d92008-11-14 10:39:19 +1100176 /* don't need to get the RCU readlock here - the process is dead and
177 * can't be modifying its own credentials */
178 atomic_dec(&__task_cred(p)->user->processes);
179
Pavel Emelyanov60347f62007-10-18 23:40:03 -0700180 proc_flush_task(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 write_lock_irq(&tasklist_lock);
Roland McGrathdae33572008-07-25 19:45:48 -0700182 tracehook_finish_release_task(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 __exit_signal(p);
Oleg Nesterov35f5cad2006-03-28 16:11:19 -0800184
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 /*
186 * If we are the last non-leader member of the thread
187 * group, and the leader is zombie, then notify the
188 * group leader's parent process. (if it wants notification.)
189 */
190 zap_leader = 0;
191 leader = p->group_leader;
192 if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
Oleg Nesterovd839fd42008-04-30 00:53:11 -0700193 BUG_ON(task_detached(leader));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 do_notify_parent(leader, leader->exit_signal);
195 /*
196 * If we were the last child thread and the leader has
197 * exited already, and the leader's parent ignores SIGCHLD,
198 * then we are the one who should release the leader.
199 *
200 * do_notify_parent() will have marked it self-reaping in
201 * that case.
202 */
Oleg Nesterovd839fd42008-04-30 00:53:11 -0700203 zap_leader = task_detached(leader);
Roland McGrathdae33572008-07-25 19:45:48 -0700204
205 /*
206 * This maintains the invariant that release_task()
207 * only runs on a task in EXIT_DEAD, just for sanity.
208 */
209 if (zap_leader)
210 leader->exit_state = EXIT_DEAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 }
212
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 write_unlock_irq(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 release_thread(p);
Eric W. Biederman8c7904a2006-03-31 02:31:37 -0800215 call_rcu(&p->rcu, delayed_put_task_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
217 p = leader;
218 if (unlikely(zap_leader))
219 goto repeat;
220}
221
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222/*
223 * This checks not only the pgrp, but falls back on the pid if no
224 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
225 * without this...
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800226 *
227 * The caller must hold rcu lock or the tasklist lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 */
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800229struct pid *session_of_pgrp(struct pid *pgrp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230{
231 struct task_struct *p;
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800232 struct pid *sid = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800234 p = pid_task(pgrp, PIDTYPE_PGID);
Oleg Nesterov62dfb552006-12-08 02:38:03 -0800235 if (p == NULL)
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800236 p = pid_task(pgrp, PIDTYPE_PID);
Oleg Nesterov62dfb552006-12-08 02:38:03 -0800237 if (p != NULL)
Eric W. Biederman04a2e6a2007-02-12 00:52:56 -0800238 sid = task_session(p);
Oleg Nesterov62dfb552006-12-08 02:38:03 -0800239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 return sid;
241}
242
243/*
244 * Determine if a process group is "orphaned", according to the POSIX
245 * definition in 2.2.2.52. Orphaned process groups are not to be affected
246 * by terminal-generated stop signals. Newly orphaned process groups are
247 * to receive a SIGHUP and a SIGCONT.
248 *
249 * "I ask you, have you ever known what it is to be an orphan?"
250 */
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800251static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252{
253 struct task_struct *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800255 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
Oleg Nesterov05e83df2008-03-02 21:44:42 +0300256 if ((p == ignored_task) ||
257 (p->exit_state && thread_group_empty(p)) ||
258 is_global_init(p->real_parent))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 continue;
Oleg Nesterov05e83df2008-03-02 21:44:42 +0300260
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800261 if (task_pgrp(p->real_parent) != pgrp &&
Oleg Nesterov05e83df2008-03-02 21:44:42 +0300262 task_session(p->real_parent) == task_session(p))
263 return 0;
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800264 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
Oleg Nesterov05e83df2008-03-02 21:44:42 +0300265
266 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267}
268
Eric W. Biederman3e7cd6c2007-02-12 00:52:58 -0800269int is_current_pgrp_orphaned(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270{
271 int retval;
272
273 read_lock(&tasklist_lock);
Eric W. Biederman3e7cd6c2007-02-12 00:52:58 -0800274 retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 read_unlock(&tasklist_lock);
276
277 return retval;
278}
279
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800280static int has_stopped_jobs(struct pid *pgrp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281{
282 int retval = 0;
283 struct task_struct *p;
284
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800285 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
Matthew Wilcox338077e2007-12-06 11:09:35 -0500286 if (!task_is_stopped(p))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 retval = 1;
289 break;
Eric W. Biederman0475ac02007-02-12 00:52:57 -0800290 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 return retval;
292}
293
Oleg Nesterovf49ee502008-03-02 21:44:40 +0300294/*
295 * Check to see if any process groups have become orphaned as
296 * a result of our exiting, and if they have any stopped jobs,
297 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
298 */
299static void
300kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
301{
302 struct pid *pgrp = task_pgrp(tsk);
303 struct task_struct *ignored_task = tsk;
304
305 if (!parent)
306 /* exit: our father is in a different pgrp than
307 * we are and we were the only connection outside.
308 */
309 parent = tsk->real_parent;
310 else
311 /* reparent: our child is in a different pgrp than
312 * we are, and it was the only connection outside.
313 */
314 ignored_task = NULL;
315
316 if (task_pgrp(parent) != pgrp &&
317 task_session(parent) == task_session(tsk) &&
318 will_become_orphaned_pgrp(pgrp, ignored_task) &&
319 has_stopped_jobs(pgrp)) {
320 __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
321 __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
322 }
323}
324
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325/**
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700326 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 *
328 * If a kernel thread is launched as a result of a system call, or if
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700329 * it ever exits, it should generally reparent itself to kthreadd so it
330 * isn't in the way of other processes and is correctly cleaned up on exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 *
332 * The various task state such as scheduling policy and priority may have
333 * been inherited from a user process, so we reset them to sane values here.
334 *
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700335 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 */
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700337static void reparent_to_kthreadd(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338{
339 write_lock_irq(&tasklist_lock);
340
341 ptrace_unlink(current);
342 /* Reparent to init */
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700343 current->real_parent = current->parent = kthreadd_task;
Roland McGrathf4700212008-03-24 18:36:23 -0700344 list_move_tail(&current->sibling, &current->real_parent->children);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345
346 /* Set the exit signal to SIGCHLD so we signal init on exit */
347 current->exit_signal = SIGCHLD;
348
Ingo Molnare05606d2007-07-09 18:51:59 +0200349 if (task_nice(current) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 set_user_nice(current, 0);
351 /* cpus_allowed? */
352 /* rt_priority? */
353 /* signals? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 memcpy(current->signal->rlim, init_task.signal->rlim,
355 sizeof(current->signal->rlim));
David Howellsd84f4f92008-11-14 10:39:23 +1100356
357 atomic_inc(&init_cred.usage);
358 commit_creds(&init_cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 write_unlock_irq(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360}
361
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800362void __set_special_pids(struct pid *pid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363{
Oren Laadane19f2472006-01-08 01:03:58 -0800364 struct task_struct *curr = current->group_leader;
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800365 pid_t nr = pid_nr(pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800367 if (task_session(curr) != pid) {
Oleg Nesterov7d8da092008-04-30 00:54:27 -0700368 change_pid(curr, PIDTYPE_SID, pid);
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800369 set_task_session(curr, nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 }
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800371 if (task_pgrp(curr) != pid) {
Oleg Nesterov7d8da092008-04-30 00:54:27 -0700372 change_pid(curr, PIDTYPE_PGID, pid);
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800373 set_task_pgrp(curr, nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 }
375}
376
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800377static void set_special_pids(struct pid *pid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378{
379 write_lock_irq(&tasklist_lock);
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800380 __set_special_pids(pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 write_unlock_irq(&tasklist_lock);
382}
383
384/*
385 * Let kernel threads use this to say that they
386 * allow a certain signal (since daemonize() will
387 * have disabled all of them by default).
388 */
389int allow_signal(int sig)
390{
Jesper Juhl7ed20e12005-05-01 08:59:14 -0700391 if (!valid_signal(sig) || sig < 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 return -EINVAL;
393
394 spin_lock_irq(&current->sighand->siglock);
395 sigdelset(&current->blocked, sig);
396 if (!current->mm) {
397 /* Kernel threads handle their own signals.
398 Let the signal code know it'll be handled, so
399 that they don't get converted to SIGKILL or
400 just silently dropped */
401 current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
402 }
403 recalc_sigpending();
404 spin_unlock_irq(&current->sighand->siglock);
405 return 0;
406}
407
408EXPORT_SYMBOL(allow_signal);
409
410int disallow_signal(int sig)
411{
Jesper Juhl7ed20e12005-05-01 08:59:14 -0700412 if (!valid_signal(sig) || sig < 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 return -EINVAL;
414
415 spin_lock_irq(&current->sighand->siglock);
Oleg Nesterov10ab8252007-05-09 02:34:37 -0700416 current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 recalc_sigpending();
418 spin_unlock_irq(&current->sighand->siglock);
419 return 0;
420}
421
422EXPORT_SYMBOL(disallow_signal);
423
424/*
425 * Put all the gunge required to become a kernel thread without
426 * attached user resources in one place where it belongs.
427 */
428
429void daemonize(const char *name, ...)
430{
431 va_list args;
432 struct fs_struct *fs;
433 sigset_t blocked;
434
435 va_start(args, name);
436 vsnprintf(current->comm, sizeof(current->comm), name, args);
437 va_end(args);
438
439 /*
440 * If we were started as result of loading a module, close all of the
441 * user space pages. We don't need them, and if we didn't close them
442 * they would be locked into memory.
443 */
444 exit_mm(current);
Rafael J. Wysocki83144182007-07-17 04:03:35 -0700445 /*
446 * We don't want to have TIF_FREEZE set if the system-wide hibernation
447 * or suspend transition begins right now.
448 */
Oleg Nesterov7b34e422008-07-25 01:47:37 -0700449 current->flags |= (PF_NOFREEZE | PF_KTHREAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450
Oleg Nesterov8520d7c2008-02-08 04:19:09 -0800451 if (current->nsproxy != &init_nsproxy) {
452 get_nsproxy(&init_nsproxy);
453 switch_task_namespaces(current, &init_nsproxy);
454 }
Oleg Nesterov297bd422008-02-08 04:19:10 -0800455 set_special_pids(&init_struct_pid);
Peter Zijlstra24ec8392006-12-08 02:36:04 -0800456 proc_clear_tty(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457
458 /* Block and flush all signals */
459 sigfillset(&blocked);
460 sigprocmask(SIG_BLOCK, &blocked, NULL);
461 flush_signals(current);
462
463 /* Become as one with the init task */
464
465 exit_fs(current); /* current->fs->count--; */
466 fs = init_task.fs;
467 current->fs = fs;
468 atomic_inc(&fs->count);
Serge E. Hallynab516012006-10-02 02:18:06 -0700469
Daniel Walkerd4c5e412007-10-18 23:39:59 -0700470 exit_files(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 current->files = init_task.files;
472 atomic_inc(&current->files->count);
473
Eric W. Biederman49d769d2007-05-09 02:34:33 -0700474 reparent_to_kthreadd();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475}
476
477EXPORT_SYMBOL(daemonize);
478
Arjan van de Ven858119e2006-01-14 13:20:43 -0800479static void close_files(struct files_struct * files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480{
481 int i, j;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700482 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483
484 j = 0;
Dipankar Sarma4fb3a532005-09-16 19:28:13 -0700485
486 /*
487 * It is safe to dereference the fd table without RCU or
488 * ->file_lock because this is the last reference to the
489 * files structure.
490 */
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700491 fdt = files_fdtable(files);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 for (;;) {
493 unsigned long set;
494 i = j * __NFDBITS;
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800495 if (i >= fdt->max_fds)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 break;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700497 set = fdt->open_fds->fds_bits[j++];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 while (set) {
499 if (set & 1) {
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700500 struct file * file = xchg(&fdt->fd[i], NULL);
Ingo Molnar944be0b2007-02-12 00:52:26 -0800501 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 filp_close(file, files);
Ingo Molnar944be0b2007-02-12 00:52:26 -0800503 cond_resched();
504 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 }
506 i++;
507 set >>= 1;
508 }
509 }
510}
511
512struct files_struct *get_files_struct(struct task_struct *task)
513{
514 struct files_struct *files;
515
516 task_lock(task);
517 files = task->files;
518 if (files)
519 atomic_inc(&files->count);
520 task_unlock(task);
521
522 return files;
523}
524
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -0800525void put_files_struct(struct files_struct *files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526{
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700527 struct fdtable *fdt;
528
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 if (atomic_dec_and_test(&files->count)) {
530 close_files(files);
531 /*
532 * Free the fd and fdset arrays if we expanded them.
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700533 * If the fdtable was embedded, pass files for freeing
534 * at the end of the RCU grace period. Otherwise,
535 * you can free files immediately.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 */
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700537 fdt = files_fdtable(files);
Vadim Lobanov4fd45812006-12-10 02:21:17 -0800538 if (fdt != &files->fdtab)
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700539 kmem_cache_free(files_cachep, files);
Vadim Lobanov01b2d932006-12-22 01:10:43 -0800540 free_fdtable(fdt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 }
542}
543
Al Viro3b125382008-04-22 05:31:30 -0400544void reset_files_struct(struct files_struct *files)
Kirill Korotaev3b9b8ab2006-09-29 02:00:05 -0700545{
Al Viro3b125382008-04-22 05:31:30 -0400546 struct task_struct *tsk = current;
Kirill Korotaev3b9b8ab2006-09-29 02:00:05 -0700547 struct files_struct *old;
548
549 old = tsk->files;
550 task_lock(tsk);
551 tsk->files = files;
552 task_unlock(tsk);
553 put_files_struct(old);
554}
Kirill Korotaev3b9b8ab2006-09-29 02:00:05 -0700555
Al Viro1ec7f1d2008-04-22 05:35:42 -0400556void exit_files(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557{
558 struct files_struct * files = tsk->files;
559
560 if (files) {
561 task_lock(tsk);
562 tsk->files = NULL;
563 task_unlock(tsk);
564 put_files_struct(files);
565 }
566}
567
Al Viro1ec7f1d2008-04-22 05:35:42 -0400568void put_fs_struct(struct fs_struct *fs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569{
570 /* No need to hold fs->lock if we are killing it */
571 if (atomic_dec_and_test(&fs->count)) {
Jan Blunck6ac08c32008-02-14 19:34:38 -0800572 path_put(&fs->root);
573 path_put(&fs->pwd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 kmem_cache_free(fs_cachep, fs);
575 }
576}
577
Al Viro1ec7f1d2008-04-22 05:35:42 -0400578void exit_fs(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579{
580 struct fs_struct * fs = tsk->fs;
581
582 if (fs) {
583 task_lock(tsk);
584 tsk->fs = NULL;
585 task_unlock(tsk);
Al Viro1ec7f1d2008-04-22 05:35:42 -0400586 put_fs_struct(fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 }
588}
589
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590EXPORT_SYMBOL_GPL(exit_fs);
591
Balbir Singhcf475ad2008-04-29 01:00:16 -0700592#ifdef CONFIG_MM_OWNER
593/*
594 * Task p is exiting and it owned mm, lets find a new owner for it
595 */
596static inline int
597mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
598{
599 /*
600 * If there are other users of the mm and the owner (us) is exiting
601 * we need to find a new owner to take on the responsibility.
602 */
Balbir Singhcf475ad2008-04-29 01:00:16 -0700603 if (atomic_read(&mm->mm_users) <= 1)
604 return 0;
605 if (mm->owner != p)
606 return 0;
607 return 1;
608}
609
610void mm_update_next_owner(struct mm_struct *mm)
611{
612 struct task_struct *c, *g, *p = current;
613
614retry:
615 if (!mm_need_new_owner(mm, p))
616 return;
617
618 read_lock(&tasklist_lock);
619 /*
620 * Search in the children
621 */
622 list_for_each_entry(c, &p->children, sibling) {
623 if (c->mm == mm)
624 goto assign_new_owner;
625 }
626
627 /*
628 * Search in the siblings
629 */
630 list_for_each_entry(c, &p->parent->children, sibling) {
631 if (c->mm == mm)
632 goto assign_new_owner;
633 }
634
635 /*
636 * Search through everything else. We should not get
637 * here often
638 */
639 do_each_thread(g, c) {
640 if (c->mm == mm)
641 goto assign_new_owner;
642 } while_each_thread(g, c);
643
644 read_unlock(&tasklist_lock);
Balbir Singh31a78f22008-09-28 23:09:31 +0100645 /*
646 * We found no owner yet mm_users > 1: this implies that we are
647 * most likely racing with swapoff (try_to_unuse()) or /proc or
Hugh Dickinse5991372009-01-06 14:39:22 -0800648 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
Balbir Singh31a78f22008-09-28 23:09:31 +0100649 */
Balbir Singh31a78f22008-09-28 23:09:31 +0100650 mm->owner = NULL;
Balbir Singhcf475ad2008-04-29 01:00:16 -0700651 return;
652
653assign_new_owner:
654 BUG_ON(c == p);
655 get_task_struct(c);
656 /*
657 * The task_lock protects c->mm from changing.
658 * We always want mm->owner->mm == mm
659 */
660 task_lock(c);
Hugh Dickinse5991372009-01-06 14:39:22 -0800661 /*
662 * Delay read_unlock() till we have the task_lock()
663 * to ensure that c does not slip away underneath us
664 */
665 read_unlock(&tasklist_lock);
Balbir Singhcf475ad2008-04-29 01:00:16 -0700666 if (c->mm != mm) {
667 task_unlock(c);
668 put_task_struct(c);
669 goto retry;
670 }
Balbir Singhcf475ad2008-04-29 01:00:16 -0700671 mm->owner = c;
672 task_unlock(c);
673 put_task_struct(c);
674}
675#endif /* CONFIG_MM_OWNER */
676
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677/*
678 * Turn us into a lazy TLB process if we
679 * aren't already..
680 */
Adrian Bunk408b6642005-05-01 08:59:29 -0700681static void exit_mm(struct task_struct * tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682{
683 struct mm_struct *mm = tsk->mm;
Oleg Nesterovb564daf2008-07-25 01:47:44 -0700684 struct core_state *core_state;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685
686 mm_release(tsk, mm);
687 if (!mm)
688 return;
689 /*
690 * Serialize with any possible pending coredump.
Oleg Nesterov999d9fc2008-07-25 01:47:41 -0700691 * We must hold mmap_sem around checking core_state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 * and clearing tsk->mm. The core-inducing thread
Oleg Nesterov999d9fc2008-07-25 01:47:41 -0700693 * will increment ->nr_threads for each thread in the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 * group with ->mm != NULL.
695 */
696 down_read(&mm->mmap_sem);
Oleg Nesterovb564daf2008-07-25 01:47:44 -0700697 core_state = mm->core_state;
698 if (core_state) {
699 struct core_thread self;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 up_read(&mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701
Oleg Nesterovb564daf2008-07-25 01:47:44 -0700702 self.task = tsk;
703 self.next = xchg(&core_state->dumper.next, &self);
704 /*
705 * Implies mb(), the result of xchg() must be visible
706 * to core_state->dumper.
707 */
708 if (atomic_dec_and_test(&core_state->nr_threads))
709 complete(&core_state->startup);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710
Oleg Nesterova94e2d42008-07-25 01:47:46 -0700711 for (;;) {
712 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
713 if (!self.task) /* see coredump_finish() */
714 break;
715 schedule();
716 }
717 __set_task_state(tsk, TASK_RUNNING);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 down_read(&mm->mmap_sem);
719 }
720 atomic_inc(&mm->mm_count);
Eric Sesterhenn125e1872006-06-23 02:06:06 -0700721 BUG_ON(mm != tsk->active_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 /* more a memory barrier than a real lock */
723 task_lock(tsk);
724 tsk->mm = NULL;
725 up_read(&mm->mmap_sem);
726 enter_lazy_tlb(mm, current);
Rafael J. Wysocki0c1eecf2007-07-19 01:47:33 -0700727 /* We don't want this task to be frozen prematurely */
728 clear_freeze_flag(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 task_unlock(tsk);
Balbir Singhcf475ad2008-04-29 01:00:16 -0700730 mm_update_next_owner(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 mmput(mm);
732}
733
Roland McGrathf4700212008-03-24 18:36:23 -0700734/*
Oleg Nesterov6d69cb82009-04-02 16:58:12 -0700735 * Called with irqs disabled, returns true if childs should reap themselves.
Roland McGrath666f1642008-04-08 23:12:30 -0700736 */
Oleg Nesterov6d69cb82009-04-02 16:58:12 -0700737static int ignoring_children(struct sighand_struct *sigh)
Roland McGrath666f1642008-04-08 23:12:30 -0700738{
739 int ret;
Oleg Nesterov6d69cb82009-04-02 16:58:12 -0700740 spin_lock(&sigh->siglock);
741 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
742 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
743 spin_unlock(&sigh->siglock);
Roland McGrath666f1642008-04-08 23:12:30 -0700744 return ret;
745}
746
747/*
Roland McGrathf4700212008-03-24 18:36:23 -0700748 * Detach all tasks we were using ptrace on.
749 * Any that need to be release_task'd are put on the @dead list.
750 *
751 * Called with write_lock(&tasklist_lock) held.
752 */
753static void ptrace_exit(struct task_struct *parent, struct list_head *dead)
754{
755 struct task_struct *p, *n;
756
757 list_for_each_entry_safe(p, n, &parent->ptraced, ptrace_entry) {
758 __ptrace_unlink(p);
759
760 if (p->exit_state != EXIT_ZOMBIE)
761 continue;
762
763 /*
764 * If it's a zombie, our attachedness prevented normal
765 * parent notification or self-reaping. Do notification
766 * now if it would have happened earlier. If it should
767 * reap itself, add it to the @dead list. We can't call
768 * release_task() here because we already hold tasklist_lock.
769 *
770 * If it's our own child, there is no notification to do.
Roland McGrath666f1642008-04-08 23:12:30 -0700771 * But if our normal children self-reap, then this child
772 * was prevented by ptrace and we must reap it now.
Roland McGrathf4700212008-03-24 18:36:23 -0700773 */
774 if (!task_detached(p) && thread_group_empty(p)) {
775 if (!same_thread_group(p->real_parent, parent))
776 do_notify_parent(p, p->exit_signal);
Oleg Nesterov6d69cb82009-04-02 16:58:12 -0700777 else if (ignoring_children(parent->sighand))
778 p->exit_signal = -1;
Roland McGrathf4700212008-03-24 18:36:23 -0700779 }
780
781 if (task_detached(p)) {
782 /*
783 * Mark it as in the process of being reaped.
784 */
785 p->exit_state = EXIT_DEAD;
786 list_add(&p->ptrace_entry, dead);
787 }
788 }
789}
790
791/*
792 * Finish up exit-time ptrace cleanup.
793 *
794 * Called without locks.
795 */
796static void ptrace_exit_finish(struct task_struct *parent,
797 struct list_head *dead)
798{
799 struct task_struct *p, *n;
800
801 BUG_ON(!list_empty(&parent->ptraced));
802
803 list_for_each_entry_safe(p, n, dead, ptrace_entry) {
804 list_del_init(&p->ptrace_entry);
805 release_task(p);
806 }
807}
808
809static void reparent_thread(struct task_struct *p, struct task_struct *father)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810{
Oleg Nesterov241ceee2006-12-24 23:30:44 +0300811 if (p->pdeath_signal)
812 /* We already hold the tasklist_lock here. */
813 group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
814
Roland McGrathf4700212008-03-24 18:36:23 -0700815 list_move_tail(&p->sibling, &p->real_parent->children);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816
Eric W. Biedermanb2b2cbc2006-12-21 21:28:40 -0700817 /* If this is a threaded reparent there is no need to
818 * notify anyone anything has happened.
819 */
Oleg Nesterov376e1d22008-04-30 00:53:12 -0700820 if (same_thread_group(p->real_parent, father))
Eric W. Biedermanb2b2cbc2006-12-21 21:28:40 -0700821 return;
822
823 /* We don't want people slaying init. */
Oleg Nesterovd839fd42008-04-30 00:53:11 -0700824 if (!task_detached(p))
Eric W. Biedermanb2b2cbc2006-12-21 21:28:40 -0700825 p->exit_signal = SIGCHLD;
Eric W. Biedermanb2b2cbc2006-12-21 21:28:40 -0700826
827 /* If we'd notified the old parent about this child's death,
828 * also notify the new parent.
829 */
Roland McGrathf4700212008-03-24 18:36:23 -0700830 if (!ptrace_reparented(p) &&
831 p->exit_state == EXIT_ZOMBIE &&
Oleg Nesterovd839fd42008-04-30 00:53:11 -0700832 !task_detached(p) && thread_group_empty(p))
Eric W. Biedermanb2b2cbc2006-12-21 21:28:40 -0700833 do_notify_parent(p, p->exit_signal);
834
Oleg Nesterovf49ee502008-03-02 21:44:40 +0300835 kill_orphaned_pgrp(p, father);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836}
837
838/*
839 * When we die, we re-parent all our children.
840 * Try to give them to another thread in our thread
841 * group, and if no such member exists, give it to
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -0800842 * the child reaper process (ie "init") in our pid
843 * space.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 */
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700845static struct task_struct *find_new_reaper(struct task_struct *father)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846{
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700847 struct pid_namespace *pid_ns = task_active_pid_ns(father);
848 struct task_struct *thread;
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700849
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700850 thread = father;
851 while_each_thread(father, thread) {
852 if (thread->flags & PF_EXITING)
853 continue;
854 if (unlikely(pid_ns->child_reaper == father))
855 pid_ns->child_reaper = thread;
856 return thread;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 }
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700858
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700859 if (unlikely(pid_ns->child_reaper == father)) {
860 write_unlock_irq(&tasklist_lock);
861 if (unlikely(pid_ns == &init_pid_ns))
862 panic("Attempted to kill init!");
863
864 zap_pid_ns_processes(pid_ns);
865 write_lock_irq(&tasklist_lock);
866 /*
867 * We can not clear ->child_reaper or leave it alone.
868 * There may by stealth EXIT_DEAD tasks on ->children,
869 * forget_original_parent() must move them somewhere.
870 */
871 pid_ns->child_reaper = init_pid_ns.child_reaper;
872 }
873
874 return pid_ns->child_reaper;
875}
876
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877static void forget_original_parent(struct task_struct *father)
878{
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700879 struct task_struct *p, *n, *reaper;
Roland McGrathf4700212008-03-24 18:36:23 -0700880 LIST_HEAD(ptrace_dead);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881
882 write_lock_irq(&tasklist_lock);
Oleg Nesterov950bbab2008-09-02 14:35:49 -0700883 reaper = find_new_reaper(father);
Roland McGrathf4700212008-03-24 18:36:23 -0700884 /*
885 * First clean up ptrace if we were using it.
886 */
887 ptrace_exit(father, &ptrace_dead);
888
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 list_for_each_entry_safe(p, n, &father->children, sibling) {
Oleg Nesterov84eb6462007-10-16 23:26:49 -0700890 p->real_parent = reaper;
Roland McGrathf4700212008-03-24 18:36:23 -0700891 if (p->parent == father) {
892 BUG_ON(p->ptrace);
893 p->parent = p->real_parent;
894 }
895 reparent_thread(p, father);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 }
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700897
898 write_unlock_irq(&tasklist_lock);
899 BUG_ON(!list_empty(&father->children));
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700900
Roland McGrathf4700212008-03-24 18:36:23 -0700901 ptrace_exit_finish(father, &ptrace_dead);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902}
903
904/*
905 * Send signals to all our closest relatives so that they know
906 * to properly mourn us..
907 */
Oleg Nesterov821c7de2008-03-02 21:44:44 +0300908static void exit_notify(struct task_struct *tsk, int group_dead)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909{
Roland McGrath2b2a1ff2008-07-25 19:45:54 -0700910 int signal;
911 void *cookie;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 /*
914 * This does two things:
915 *
916 * A. Make init inherit all the child processes
917 * B. Check to see if any process groups have become orphaned
918 * as a result of our exiting, and if they have any stopped
919 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
920 */
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700921 forget_original_parent(tsk);
Pavel Emelyanov2e4a7072007-10-18 23:40:01 -0700922 exit_task_namespaces(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923
Oleg Nesterov762a24b2007-10-18 23:40:00 -0700924 write_lock_irq(&tasklist_lock);
Oleg Nesterov821c7de2008-03-02 21:44:44 +0300925 if (group_dead)
926 kill_orphaned_pgrp(tsk->group_leader, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927
Oleg Nesterov24728442007-08-04 01:04:41 +0400928 /* Let father know we died
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 *
930 * Thread signals are configurable, but you aren't going to use
Daniel Walkerd4c5e412007-10-18 23:39:59 -0700931 * that to send signals to arbitary processes.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 * That stops right now.
933 *
934 * If the parent exec id doesn't match the exec id we saved
935 * when we started then we know the parent has changed security
936 * domain.
937 *
938 * If our self_exec id doesn't match our parent_exec_id then
939 * we have changed execution domain as these two values started
940 * the same after a fork.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 */
Oleg Nesterovd839fd42008-04-30 00:53:11 -0700942 if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) &&
Oleg Nesterovf49ee502008-03-02 21:44:40 +0300943 (tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
Oleg Nesterovd839fd42008-04-30 00:53:11 -0700944 tsk->self_exec_id != tsk->parent_exec_id) &&
945 !capable(CAP_KILL))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 tsk->exit_signal = SIGCHLD;
947
Roland McGrath2b2a1ff2008-07-25 19:45:54 -0700948 signal = tracehook_notify_death(tsk, &cookie, group_dead);
Roland McGrath5c7edcd2008-07-31 02:04:09 -0700949 if (signal >= 0)
Roland McGrath2b2a1ff2008-07-25 19:45:54 -0700950 signal = do_notify_parent(tsk, signal);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951
Roland McGrath5c7edcd2008-07-31 02:04:09 -0700952 tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953
Oleg Nesterov2800d8d2008-04-30 00:53:12 -0700954 /* mt-exec, de_thread() is waiting for us */
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700955 if (thread_group_leader(tsk) &&
Steve VanDeBogart2633f0e2008-08-26 15:14:36 -0700956 tsk->signal->group_exit_task &&
957 tsk->signal->notify_count < 0)
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700958 wake_up_process(tsk->signal->group_exit_task);
959
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 write_unlock_irq(&tasklist_lock);
961
Roland McGrath2b2a1ff2008-07-25 19:45:54 -0700962 tracehook_report_death(tsk, signal, cookie, group_dead);
963
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 /* If the process is dead, release it - nobody will wait for it */
Roland McGrath5c7edcd2008-07-31 02:04:09 -0700965 if (signal == DEATH_REAP)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 release_task(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967}
968
Jeff Dikee18eecb2007-07-15 23:38:48 -0700969#ifdef CONFIG_DEBUG_STACK_USAGE
970static void check_stack_usage(void)
971{
972 static DEFINE_SPINLOCK(low_water_lock);
973 static int lowest_to_date = THREAD_SIZE;
Jeff Dikee18eecb2007-07-15 23:38:48 -0700974 unsigned long free;
975
Eric Sandeen7c9f8862008-04-22 16:38:23 -0500976 free = stack_not_used(current);
Jeff Dikee18eecb2007-07-15 23:38:48 -0700977
978 if (free >= lowest_to_date)
979 return;
980
981 spin_lock(&low_water_lock);
982 if (free < lowest_to_date) {
983 printk(KERN_WARNING "%s used greatest stack depth: %lu bytes "
984 "left\n",
985 current->comm, free);
986 lowest_to_date = free;
987 }
988 spin_unlock(&low_water_lock);
989}
990#else
991static inline void check_stack_usage(void) {}
992#endif
993
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -0800994NORET_TYPE void do_exit(long code)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995{
996 struct task_struct *tsk = current;
997 int group_dead;
998
999 profile_task_exit(tsk);
1000
Jens Axboe22e2c502005-06-27 10:55:12 +02001001 WARN_ON(atomic_read(&tsk->fs_excl));
1002
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 if (unlikely(in_interrupt()))
1004 panic("Aiee, killing interrupt handler!");
1005 if (unlikely(!tsk->pid))
1006 panic("Attempted to kill the idle task!");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007
Roland McGrath30199f52008-07-25 19:45:46 -07001008 tracehook_report_exit(&code);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009
Alexander Nybergdf164db2005-06-23 00:09:13 -07001010 /*
1011 * We're taking recursive faults here in do_exit. Safest is to just
1012 * leave this task alone and wait for reboot.
1013 */
1014 if (unlikely(tsk->flags & PF_EXITING)) {
1015 printk(KERN_ALERT
1016 "Fixing recursive fault but reboot is needed!\n");
Alexey Kuznetsov778e9a92007-06-08 13:47:00 -07001017 /*
1018 * We can do this unlocked here. The futex code uses
1019 * this flag just to verify whether the pi state
1020 * cleanup has been done or not. In the worst case it
1021 * loops once more. We pretend that the cleanup was
1022 * done as there is no way to return. Either the
1023 * OWNER_DIED bit is set by now or we push the blocked
1024 * task into the wait for ever nirwana as well.
1025 */
1026 tsk->flags |= PF_EXITPIDONE;
Alexander Nybergdf164db2005-06-23 00:09:13 -07001027 set_current_state(TASK_UNINTERRUPTIBLE);
1028 schedule();
1029 }
1030
Oleg Nesterovd12619b2008-02-08 04:19:12 -08001031 exit_signals(tsk); /* sets PF_EXITING */
Alexey Kuznetsov778e9a92007-06-08 13:47:00 -07001032 /*
1033 * tsk->flags are checked in the futex code to protect against
1034 * an exiting task cleaning up the robust pi futexes.
1035 */
Oleg Nesterovd2ee7192007-10-16 23:26:47 -07001036 smp_mb();
1037 spin_unlock_wait(&tsk->pi_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039 if (unlikely(in_atomic()))
1040 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07001041 current->comm, task_pid_nr(current),
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042 preempt_count());
1043
1044 acct_update_integrals(tsk);
Oleg Nesterov901608d2009-01-06 14:40:29 -08001045
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 group_dead = atomic_dec_and_test(&tsk->signal->live);
Andrew Mortonc3068952005-08-04 16:49:32 -07001047 if (group_dead) {
Alexey Kuznetsov778e9a92007-06-08 13:47:00 -07001048 hrtimer_cancel(&tsk->signal->real_timer);
Roland McGrath25f407f2005-10-21 15:03:29 -07001049 exit_itimers(tsk->signal);
Andrew Mortonc3068952005-08-04 16:49:32 -07001050 }
KaiGai Koheif6ec29a2006-06-25 05:49:25 -07001051 acct_collect(code, group_dead);
Miloslav Trmac522ed772007-07-15 23:40:56 -07001052 if (group_dead)
1053 tty_audit_exit();
Al Virofa84cb92006-03-29 20:30:19 -05001054 if (unlikely(tsk->audit_context))
1055 audit_free(tsk);
Oleg Nesterov115085e2006-12-06 20:36:51 -08001056
Jonathan Limf2ab6d82007-08-30 23:56:23 -07001057 tsk->exit_code = code;
Oleg Nesterov115085e2006-12-06 20:36:51 -08001058 taskstats_exit(tsk, group_dead);
Shailabh Nagarc7572492006-07-14 00:24:40 -07001059
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060 exit_mm(tsk);
1061
KaiGai Kohei0e464812006-06-25 05:49:24 -07001062 if (group_dead)
KaiGai Koheif6ec29a2006-06-25 05:49:25 -07001063 acct_process();
Mathieu Desnoyers0a16b602008-07-18 12:16:17 -04001064 trace_sched_process_exit(tsk);
1065
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066 exit_sem(tsk);
Al Viro1ec7f1d2008-04-22 05:35:42 -04001067 exit_files(tsk);
1068 exit_fs(tsk);
Jeff Dikee18eecb2007-07-15 23:38:48 -07001069 check_stack_usage();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 exit_thread();
Paul Menageb4f48b62007-10-18 23:39:33 -07001071 cgroup_exit(tsk, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072
1073 if (group_dead && tsk->signal->leader)
1074 disassociate_ctty(1);
1075
Al Viroa1261f52005-11-13 16:06:55 -08001076 module_put(task_thread_info(tsk)->exec_domain->module);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 if (tsk->binfmt)
1078 module_put(tsk->binfmt->module);
1079
Matt Helsley9f460802005-11-07 00:59:16 -08001080 proc_exit_connector(tsk);
Oleg Nesterov821c7de2008-03-02 21:44:44 +03001081 exit_notify(tsk, group_dead);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082#ifdef CONFIG_NUMA
Lee Schermerhornf0be3d32008-04-28 02:13:08 -07001083 mpol_put(tsk->mempolicy);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084 tsk->mempolicy = NULL;
1085#endif
Alexey Dobriyan42b2dd02007-10-16 23:27:30 -07001086#ifdef CONFIG_FUTEX
Ingo Molnarde5097c2006-01-09 15:59:21 -08001087 /*
Ingo Molnarc87e2832006-06-27 02:54:58 -07001088 * This must happen late, after the PID is not
1089 * hashed anymore:
1090 */
1091 if (unlikely(!list_empty(&tsk->pi_state_list)))
1092 exit_pi_state_list(tsk);
1093 if (unlikely(current->pi_state_cache))
1094 kfree(current->pi_state_cache);
Alexey Dobriyan42b2dd02007-10-16 23:27:30 -07001095#endif
Ingo Molnarc87e2832006-06-27 02:54:58 -07001096 /*
Ingo Molnar9a11b49a2006-07-03 00:24:33 -07001097 * Make sure we are holding no locks:
Ingo Molnarde5097c2006-01-09 15:59:21 -08001098 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -07001099 debug_check_no_locks_held(tsk);
Alexey Kuznetsov778e9a92007-06-08 13:47:00 -07001100 /*
1101 * We can do this unlocked here. The futex code uses this flag
1102 * just to verify whether the pi state cleanup has been done
1103 * or not. In the worst case it loops once more.
1104 */
1105 tsk->flags |= PF_EXITPIDONE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106
Al Viroafc847b2006-02-28 12:51:55 -05001107 if (tsk->io_context)
1108 exit_io_context();
1109
Jens Axboeb92ce552006-04-11 13:52:07 +02001110 if (tsk->splice_pipe)
1111 __free_pipe_info(tsk->splice_pipe);
1112
Coywolf Qi Hunt74072512005-10-30 15:02:47 -08001113 preempt_disable();
Oleg Nesterov55a101f2006-09-29 02:01:10 -07001114 /* causes final put_task_struct in finish_task_switch(). */
Oleg Nesterovc394cc92006-09-29 02:01:11 -07001115 tsk->state = TASK_DEAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 schedule();
1117 BUG();
1118 /* Avoid "noreturn function does return". */
Alan Cox54306cf2006-09-29 02:00:42 -07001119 for (;;)
1120 cpu_relax(); /* For when BUG is null */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121}
1122
Russ Anderson012914d2005-04-23 00:08:00 -07001123EXPORT_SYMBOL_GPL(do_exit);
1124
Linus Torvalds1da177e2005-04-16 15:20:36 -07001125NORET_TYPE void complete_and_exit(struct completion *comp, long code)
1126{
1127 if (comp)
1128 complete(comp);
Oleg Nesterov55a101f2006-09-29 02:01:10 -07001129
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130 do_exit(code);
1131}
1132
1133EXPORT_SYMBOL(complete_and_exit);
1134
Heiko Carstens754fe8d2009-01-14 14:14:09 +01001135SYSCALL_DEFINE1(exit, int, error_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136{
1137 do_exit((error_code&0xff)<<8);
1138}
1139
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140/*
1141 * Take down every thread in the group. This is called by fatal signals
1142 * as well as by sys_exit_group (below).
1143 */
1144NORET_TYPE void
1145do_group_exit(int exit_code)
1146{
Oleg Nesterovbfc4b082008-04-30 00:52:36 -07001147 struct signal_struct *sig = current->signal;
1148
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 BUG_ON(exit_code & 0x80); /* core dumps don't get here */
1150
Oleg Nesterovbfc4b082008-04-30 00:52:36 -07001151 if (signal_group_exit(sig))
1152 exit_code = sig->group_exit_code;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 else if (!thread_group_empty(current)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154 struct sighand_struct *const sighand = current->sighand;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 spin_lock_irq(&sighand->siglock);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -08001156 if (signal_group_exit(sig))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157 /* Another thread got here before we took the lock. */
1158 exit_code = sig->group_exit_code;
1159 else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160 sig->group_exit_code = exit_code;
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -08001161 sig->flags = SIGNAL_GROUP_EXIT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 zap_other_threads(current);
1163 }
1164 spin_unlock_irq(&sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165 }
1166
1167 do_exit(exit_code);
1168 /* NOTREACHED */
1169}
1170
1171/*
1172 * this kills every thread in the thread group. Note that any externally
1173 * wait4()-ing process will get the correct exit code - even if this
1174 * thread is not the thread group leader.
1175 */
Heiko Carstens754fe8d2009-01-14 14:14:09 +01001176SYSCALL_DEFINE1(exit_group, int, error_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177{
1178 do_group_exit((error_code & 0xff) << 8);
Heiko Carstens2ed7c032009-01-14 14:13:54 +01001179 /* NOTREACHED */
1180 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181}
1182
Eric W. Biederman161550d2008-02-08 04:19:14 -08001183static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
1184{
1185 struct pid *pid = NULL;
1186 if (type == PIDTYPE_PID)
1187 pid = task->pids[type].pid;
1188 else if (type < PIDTYPE_MAX)
1189 pid = task->group_leader->pids[type].pid;
1190 return pid;
1191}
1192
1193static int eligible_child(enum pid_type type, struct pid *pid, int options,
1194 struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195{
Roland McGrath73243282007-05-06 14:50:20 -07001196 int err;
1197
Eric W. Biederman161550d2008-02-08 04:19:14 -08001198 if (type < PIDTYPE_MAX) {
1199 if (task_pid_type(p, type) != pid)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 return 0;
1201 }
1202
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 /* Wait for all children (clone and not) if __WALL is set;
1204 * otherwise, wait for clone children *only* if __WCLONE is
1205 * set; otherwise, wait for non-clone children *only*. (Note:
1206 * A "clone" child here is one that reports to its parent
1207 * using a signal other than SIGCHLD.) */
1208 if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
1209 && !(options & __WALL))
1210 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211
Roland McGrath73243282007-05-06 14:50:20 -07001212 err = security_task_wait(p);
Roland McGrath14dd0b82008-03-30 18:41:25 -07001213 if (err)
1214 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215
Roland McGrath14dd0b82008-03-30 18:41:25 -07001216 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217}
1218
Ingo Molnar36c8b582006-07-03 00:25:41 -07001219static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220 int why, int status,
1221 struct siginfo __user *infop,
1222 struct rusage __user *rusagep)
1223{
1224 int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
Ingo Molnar36c8b582006-07-03 00:25:41 -07001225
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226 put_task_struct(p);
1227 if (!retval)
1228 retval = put_user(SIGCHLD, &infop->si_signo);
1229 if (!retval)
1230 retval = put_user(0, &infop->si_errno);
1231 if (!retval)
1232 retval = put_user((short)why, &infop->si_code);
1233 if (!retval)
1234 retval = put_user(pid, &infop->si_pid);
1235 if (!retval)
1236 retval = put_user(uid, &infop->si_uid);
1237 if (!retval)
1238 retval = put_user(status, &infop->si_status);
1239 if (!retval)
1240 retval = pid;
1241 return retval;
1242}
1243
1244/*
1245 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1246 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1247 * the lock and this task is uninteresting. If we return nonzero, we have
1248 * released the lock and the system call should return.
1249 */
Roland McGrath98abed02008-03-19 19:24:59 -07001250static int wait_task_zombie(struct task_struct *p, int options,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 struct siginfo __user *infop,
1252 int __user *stat_addr, struct rusage __user *ru)
1253{
1254 unsigned long state;
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001255 int retval, status, traced;
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08001256 pid_t pid = task_pid_vnr(p);
David Howellsc69e8d92008-11-14 10:39:19 +11001257 uid_t uid = __task_cred(p)->uid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258
Roland McGrath98abed02008-03-19 19:24:59 -07001259 if (!likely(options & WEXITED))
1260 return 0;
1261
1262 if (unlikely(options & WNOWAIT)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 int exit_code = p->exit_code;
1264 int why, status;
1265
Linus Torvalds1da177e2005-04-16 15:20:36 -07001266 get_task_struct(p);
1267 read_unlock(&tasklist_lock);
1268 if ((exit_code & 0x7f) == 0) {
1269 why = CLD_EXITED;
1270 status = exit_code >> 8;
1271 } else {
1272 why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
1273 status = exit_code & 0x7f;
1274 }
1275 return wait_noreap_copyout(p, pid, uid, why,
1276 status, infop, ru);
1277 }
1278
1279 /*
1280 * Try to move the task's state to DEAD
1281 * only one thread is allowed to do this:
1282 */
1283 state = xchg(&p->exit_state, EXIT_DEAD);
1284 if (state != EXIT_ZOMBIE) {
1285 BUG_ON(state != EXIT_DEAD);
1286 return 0;
1287 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288
Oleg Nesterov53b6f9f2008-04-30 00:53:13 -07001289 traced = ptrace_reparented(p);
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001290
1291 if (likely(!traced)) {
Jesper Juhl3795e162006-01-09 20:54:39 -08001292 struct signal_struct *psig;
1293 struct signal_struct *sig;
Frank Mayharf06febc2008-09-12 09:54:39 -07001294 struct task_cputime cputime;
Jesper Juhl3795e162006-01-09 20:54:39 -08001295
Linus Torvalds1da177e2005-04-16 15:20:36 -07001296 /*
1297 * The resource counters for the group leader are in its
1298 * own task_struct. Those for dead threads in the group
1299 * are in its signal_struct, as are those for the child
1300 * processes it has previously reaped. All these
1301 * accumulate in the parent's signal_struct c* fields.
1302 *
1303 * We don't bother to take a lock here to protect these
1304 * p->signal fields, because they are only touched by
1305 * __exit_signal, which runs with tasklist_lock
1306 * write-locked anyway, and so is excluded here. We do
1307 * need to protect the access to p->parent->signal fields,
1308 * as other threads in the parent group can be right
1309 * here reaping other children at the same time.
Frank Mayharf06febc2008-09-12 09:54:39 -07001310 *
1311 * We use thread_group_cputime() to get times for the thread
1312 * group, which consolidates times for all threads in the
1313 * group including the group leader.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 */
Oleg Nesterov2b5fe6d2008-11-17 15:40:08 +01001315 thread_group_cputime(p, &cputime);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316 spin_lock_irq(&p->parent->sighand->siglock);
Jesper Juhl3795e162006-01-09 20:54:39 -08001317 psig = p->parent->signal;
1318 sig = p->signal;
1319 psig->cutime =
1320 cputime_add(psig->cutime,
Frank Mayharf06febc2008-09-12 09:54:39 -07001321 cputime_add(cputime.utime,
1322 sig->cutime));
Jesper Juhl3795e162006-01-09 20:54:39 -08001323 psig->cstime =
1324 cputime_add(psig->cstime,
Frank Mayharf06febc2008-09-12 09:54:39 -07001325 cputime_add(cputime.stime,
1326 sig->cstime));
Laurent Vivier9ac52312007-10-15 17:00:19 +02001327 psig->cgtime =
1328 cputime_add(psig->cgtime,
1329 cputime_add(p->gtime,
1330 cputime_add(sig->gtime,
1331 sig->cgtime)));
Jesper Juhl3795e162006-01-09 20:54:39 -08001332 psig->cmin_flt +=
1333 p->min_flt + sig->min_flt + sig->cmin_flt;
1334 psig->cmaj_flt +=
1335 p->maj_flt + sig->maj_flt + sig->cmaj_flt;
1336 psig->cnvcsw +=
1337 p->nvcsw + sig->nvcsw + sig->cnvcsw;
1338 psig->cnivcsw +=
1339 p->nivcsw + sig->nivcsw + sig->cnivcsw;
Eric Dumazet6eaeeab2007-05-10 22:22:37 -07001340 psig->cinblock +=
1341 task_io_get_inblock(p) +
1342 sig->inblock + sig->cinblock;
1343 psig->coublock +=
1344 task_io_get_oublock(p) +
1345 sig->oublock + sig->coublock;
Andrea Righi59954772008-07-27 17:29:15 +02001346 task_io_accounting_add(&psig->ioac, &p->ioac);
1347 task_io_accounting_add(&psig->ioac, &sig->ioac);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 spin_unlock_irq(&p->parent->sighand->siglock);
1349 }
1350
1351 /*
1352 * Now we are sure this task is interesting, and no other
1353 * thread can reap it because we set its state to EXIT_DEAD.
1354 */
1355 read_unlock(&tasklist_lock);
1356
1357 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1358 status = (p->signal->flags & SIGNAL_GROUP_EXIT)
1359 ? p->signal->group_exit_code : p->exit_code;
1360 if (!retval && stat_addr)
1361 retval = put_user(status, stat_addr);
1362 if (!retval && infop)
1363 retval = put_user(SIGCHLD, &infop->si_signo);
1364 if (!retval && infop)
1365 retval = put_user(0, &infop->si_errno);
1366 if (!retval && infop) {
1367 int why;
1368
1369 if ((status & 0x7f) == 0) {
1370 why = CLD_EXITED;
1371 status >>= 8;
1372 } else {
1373 why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
1374 status &= 0x7f;
1375 }
1376 retval = put_user((short)why, &infop->si_code);
1377 if (!retval)
1378 retval = put_user(status, &infop->si_status);
1379 }
1380 if (!retval && infop)
Oleg Nesterov3a515e42008-02-08 04:19:07 -08001381 retval = put_user(pid, &infop->si_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382 if (!retval && infop)
David Howellsc69e8d92008-11-14 10:39:19 +11001383 retval = put_user(uid, &infop->si_uid);
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001384 if (!retval)
Oleg Nesterov3a515e42008-02-08 04:19:07 -08001385 retval = pid;
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001386
1387 if (traced) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388 write_lock_irq(&tasklist_lock);
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001389 /* We dropped tasklist, ptracer could die and untrace */
1390 ptrace_unlink(p);
1391 /*
1392 * If this is not a detached task, notify the parent.
1393 * If it's still not detached after that, don't release
1394 * it now.
1395 */
Oleg Nesterovd839fd42008-04-30 00:53:11 -07001396 if (!task_detached(p)) {
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001397 do_notify_parent(p, p->exit_signal);
Oleg Nesterovd839fd42008-04-30 00:53:11 -07001398 if (!task_detached(p)) {
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001399 p->exit_state = EXIT_ZOMBIE;
1400 p = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401 }
1402 }
1403 write_unlock_irq(&tasklist_lock);
1404 }
1405 if (p != NULL)
1406 release_task(p);
Oleg Nesterov2f4e6e22007-10-16 23:26:58 -07001407
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408 return retval;
1409}
1410
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001411static int *task_stopped_code(struct task_struct *p, bool ptrace)
1412{
1413 if (ptrace) {
1414 if (task_is_stopped_or_traced(p))
1415 return &p->exit_code;
1416 } else {
1417 if (p->signal->flags & SIGNAL_STOP_STOPPED)
1418 return &p->signal->group_exit_code;
1419 }
1420 return NULL;
1421}
1422
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423/*
1424 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1425 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1426 * the lock and this task is uninteresting. If we return nonzero, we have
1427 * released the lock and the system call should return.
1428 */
Roland McGrathf4700212008-03-24 18:36:23 -07001429static int wait_task_stopped(int ptrace, struct task_struct *p,
Roland McGrath98abed02008-03-19 19:24:59 -07001430 int options, struct siginfo __user *infop,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 int __user *stat_addr, struct rusage __user *ru)
1432{
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001433 int retval, exit_code, *p_code, why;
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001434 uid_t uid = 0; /* unneeded, required by compiler */
Oleg Nesterovc8950782007-11-28 16:21:24 -08001435 pid_t pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001436
Roland McGrathf4700212008-03-24 18:36:23 -07001437 if (!(options & WUNTRACED))
Roland McGrath98abed02008-03-19 19:24:59 -07001438 return 0;
1439
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001440 exit_code = 0;
1441 spin_lock_irq(&p->sighand->siglock);
1442
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001443 p_code = task_stopped_code(p, ptrace);
1444 if (unlikely(!p_code))
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001445 goto unlock_sig;
1446
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001447 exit_code = *p_code;
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001448 if (!exit_code)
1449 goto unlock_sig;
1450
Roland McGrath98abed02008-03-19 19:24:59 -07001451 if (!unlikely(options & WNOWAIT))
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001452 *p_code = 0;
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001453
David Howellsc69e8d92008-11-14 10:39:19 +11001454 /* don't need the RCU readlock here as we're holding a spinlock */
1455 uid = __task_cred(p)->uid;
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001456unlock_sig:
1457 spin_unlock_irq(&p->sighand->siglock);
1458 if (!exit_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459 return 0;
1460
1461 /*
1462 * Now we are pretty sure this task is interesting.
1463 * Make sure it doesn't get reaped out from under us while we
1464 * give up the lock and then examine it below. We don't want to
1465 * keep holding onto the tasklist_lock while we call getrusage and
1466 * possibly take page faults for user memory.
1467 */
1468 get_task_struct(p);
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08001469 pid = task_pid_vnr(p);
Roland McGrathf4700212008-03-24 18:36:23 -07001470 why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471 read_unlock(&tasklist_lock);
1472
Roland McGrath98abed02008-03-19 19:24:59 -07001473 if (unlikely(options & WNOWAIT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474 return wait_noreap_copyout(p, pid, uid,
Scott James Remnante6ceb322007-11-28 16:22:07 -08001475 why, exit_code,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476 infop, ru);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477
1478 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1479 if (!retval && stat_addr)
1480 retval = put_user((exit_code << 8) | 0x7f, stat_addr);
1481 if (!retval && infop)
1482 retval = put_user(SIGCHLD, &infop->si_signo);
1483 if (!retval && infop)
1484 retval = put_user(0, &infop->si_errno);
1485 if (!retval && infop)
Roland McGrath6efcae42008-03-08 11:41:22 -08001486 retval = put_user((short)why, &infop->si_code);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 if (!retval && infop)
1488 retval = put_user(exit_code, &infop->si_status);
1489 if (!retval && infop)
Oleg Nesterovc8950782007-11-28 16:21:24 -08001490 retval = put_user(pid, &infop->si_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 if (!retval && infop)
Oleg Nesterovee7c82d2008-02-08 04:19:01 -08001492 retval = put_user(uid, &infop->si_uid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 if (!retval)
Oleg Nesterovc8950782007-11-28 16:21:24 -08001494 retval = pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 put_task_struct(p);
1496
1497 BUG_ON(!retval);
1498 return retval;
1499}
1500
1501/*
1502 * Handle do_wait work for one task in a live, non-stopped state.
1503 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1504 * the lock and this task is uninteresting. If we return nonzero, we have
1505 * released the lock and the system call should return.
1506 */
Roland McGrath98abed02008-03-19 19:24:59 -07001507static int wait_task_continued(struct task_struct *p, int options,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 struct siginfo __user *infop,
1509 int __user *stat_addr, struct rusage __user *ru)
1510{
1511 int retval;
1512 pid_t pid;
1513 uid_t uid;
1514
Roland McGrath98abed02008-03-19 19:24:59 -07001515 if (!unlikely(options & WCONTINUED))
1516 return 0;
1517
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
1519 return 0;
1520
1521 spin_lock_irq(&p->sighand->siglock);
1522 /* Re-check with the lock held. */
1523 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
1524 spin_unlock_irq(&p->sighand->siglock);
1525 return 0;
1526 }
Roland McGrath98abed02008-03-19 19:24:59 -07001527 if (!unlikely(options & WNOWAIT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001528 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
David Howellsc69e8d92008-11-14 10:39:19 +11001529 uid = __task_cred(p)->uid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530 spin_unlock_irq(&p->sighand->siglock);
1531
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08001532 pid = task_pid_vnr(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 get_task_struct(p);
1534 read_unlock(&tasklist_lock);
1535
1536 if (!infop) {
1537 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1538 put_task_struct(p);
1539 if (!retval && stat_addr)
1540 retval = put_user(0xffff, stat_addr);
1541 if (!retval)
Oleg Nesterov3a515e42008-02-08 04:19:07 -08001542 retval = pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543 } else {
1544 retval = wait_noreap_copyout(p, pid, uid,
1545 CLD_CONTINUED, SIGCONT,
1546 infop, ru);
1547 BUG_ON(retval == 0);
1548 }
1549
1550 return retval;
1551}
1552
Roland McGrath98abed02008-03-19 19:24:59 -07001553/*
1554 * Consider @p for a wait by @parent.
1555 *
1556 * -ECHILD should be in *@notask_error before the first call.
1557 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1558 * Returns zero if the search for a child should continue;
Roland McGrath14dd0b82008-03-30 18:41:25 -07001559 * then *@notask_error is 0 if @p is an eligible child,
1560 * or another error from security_task_wait(), or still -ECHILD.
Roland McGrath98abed02008-03-19 19:24:59 -07001561 */
Roland McGrathf4700212008-03-24 18:36:23 -07001562static int wait_consider_task(struct task_struct *parent, int ptrace,
Roland McGrath98abed02008-03-19 19:24:59 -07001563 struct task_struct *p, int *notask_error,
1564 enum pid_type type, struct pid *pid, int options,
1565 struct siginfo __user *infop,
1566 int __user *stat_addr, struct rusage __user *ru)
1567{
1568 int ret = eligible_child(type, pid, options, p);
Roland McGrath14dd0b82008-03-30 18:41:25 -07001569 if (!ret)
Roland McGrath98abed02008-03-19 19:24:59 -07001570 return ret;
1571
Roland McGrath14dd0b82008-03-30 18:41:25 -07001572 if (unlikely(ret < 0)) {
1573 /*
1574 * If we have not yet seen any eligible child,
1575 * then let this error code replace -ECHILD.
1576 * A permission error will give the user a clue
1577 * to look for security policy problems, rather
1578 * than for mysterious wait bugs.
1579 */
1580 if (*notask_error)
1581 *notask_error = ret;
1582 }
1583
Roland McGrathf4700212008-03-24 18:36:23 -07001584 if (likely(!ptrace) && unlikely(p->ptrace)) {
1585 /*
1586 * This child is hidden by ptrace.
1587 * We aren't allowed to see it now, but eventually we will.
1588 */
1589 *notask_error = 0;
1590 return 0;
1591 }
1592
Roland McGrath98abed02008-03-19 19:24:59 -07001593 if (p->exit_state == EXIT_DEAD)
1594 return 0;
1595
1596 /*
1597 * We don't reap group leaders with subthreads.
1598 */
1599 if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p))
1600 return wait_task_zombie(p, options, infop, stat_addr, ru);
1601
1602 /*
1603 * It's stopped or running now, so it might
1604 * later continue, exit, or stop again.
1605 */
1606 *notask_error = 0;
1607
Oleg Nesterov90bc8d82009-04-02 16:57:58 -07001608 if (task_stopped_code(p, ptrace))
Roland McGrathf4700212008-03-24 18:36:23 -07001609 return wait_task_stopped(ptrace, p, options,
1610 infop, stat_addr, ru);
Roland McGrath98abed02008-03-19 19:24:59 -07001611
1612 return wait_task_continued(p, options, infop, stat_addr, ru);
1613}
1614
1615/*
1616 * Do the work of do_wait() for one thread in the group, @tsk.
1617 *
1618 * -ECHILD should be in *@notask_error before the first call.
1619 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1620 * Returns zero if the search for a child should continue; then
Roland McGrath14dd0b82008-03-30 18:41:25 -07001621 * *@notask_error is 0 if there were any eligible children,
1622 * or another error from security_task_wait(), or still -ECHILD.
Roland McGrath98abed02008-03-19 19:24:59 -07001623 */
1624static int do_wait_thread(struct task_struct *tsk, int *notask_error,
1625 enum pid_type type, struct pid *pid, int options,
1626 struct siginfo __user *infop, int __user *stat_addr,
1627 struct rusage __user *ru)
1628{
1629 struct task_struct *p;
1630
1631 list_for_each_entry(p, &tsk->children, sibling) {
Roland McGrathf4700212008-03-24 18:36:23 -07001632 /*
1633 * Do not consider detached threads.
1634 */
1635 if (!task_detached(p)) {
1636 int ret = wait_consider_task(tsk, 0, p, notask_error,
1637 type, pid, options,
1638 infop, stat_addr, ru);
1639 if (ret)
1640 return ret;
1641 }
Roland McGrath98abed02008-03-19 19:24:59 -07001642 }
1643
1644 return 0;
1645}
1646
1647static int ptrace_do_wait(struct task_struct *tsk, int *notask_error,
1648 enum pid_type type, struct pid *pid, int options,
1649 struct siginfo __user *infop, int __user *stat_addr,
1650 struct rusage __user *ru)
1651{
1652 struct task_struct *p;
1653
1654 /*
Roland McGrathf4700212008-03-24 18:36:23 -07001655 * Traditionally we see ptrace'd stopped tasks regardless of options.
Roland McGrath98abed02008-03-19 19:24:59 -07001656 */
Roland McGrathf4700212008-03-24 18:36:23 -07001657 options |= WUNTRACED;
Roland McGrath98abed02008-03-19 19:24:59 -07001658
Roland McGrathf4700212008-03-24 18:36:23 -07001659 list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
1660 int ret = wait_consider_task(tsk, 1, p, notask_error,
1661 type, pid, options,
1662 infop, stat_addr, ru);
1663 if (ret)
Roland McGrath98abed02008-03-19 19:24:59 -07001664 return ret;
Roland McGrath98abed02008-03-19 19:24:59 -07001665 }
1666
1667 return 0;
1668}
1669
Eric W. Biederman161550d2008-02-08 04:19:14 -08001670static long do_wait(enum pid_type type, struct pid *pid, int options,
1671 struct siginfo __user *infop, int __user *stat_addr,
1672 struct rusage __user *ru)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673{
1674 DECLARE_WAITQUEUE(wait, current);
1675 struct task_struct *tsk;
Roland McGrath98abed02008-03-19 19:24:59 -07001676 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677
Mathieu Desnoyers0a16b602008-07-18 12:16:17 -04001678 trace_sched_process_wait(pid);
1679
Linus Torvalds1da177e2005-04-16 15:20:36 -07001680 add_wait_queue(&current->signal->wait_chldexit,&wait);
1681repeat:
Roland McGrath98abed02008-03-19 19:24:59 -07001682 /*
1683 * If there is nothing that can match our critiera just get out.
1684 * We will clear @retval to zero if we see any child that might later
1685 * match our criteria, even if we are not able to reap it yet.
1686 */
Eric W. Biederman161550d2008-02-08 04:19:14 -08001687 retval = -ECHILD;
1688 if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type])))
1689 goto end;
1690
Linus Torvalds1da177e2005-04-16 15:20:36 -07001691 current->state = TASK_INTERRUPTIBLE;
1692 read_lock(&tasklist_lock);
1693 tsk = current;
1694 do {
Roland McGrath98abed02008-03-19 19:24:59 -07001695 int tsk_result = do_wait_thread(tsk, &retval,
1696 type, pid, options,
1697 infop, stat_addr, ru);
1698 if (!tsk_result)
1699 tsk_result = ptrace_do_wait(tsk, &retval,
1700 type, pid, options,
1701 infop, stat_addr, ru);
1702 if (tsk_result) {
1703 /*
1704 * tasklist_lock is unlocked and we have a final result.
1705 */
1706 retval = tsk_result;
1707 goto end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001708 }
Roland McGrath98abed02008-03-19 19:24:59 -07001709
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710 if (options & __WNOTHREAD)
1711 break;
1712 tsk = next_thread(tsk);
Eric Sesterhenn125e1872006-06-23 02:06:06 -07001713 BUG_ON(tsk->signal != current->signal);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714 } while (tsk != current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001715 read_unlock(&tasklist_lock);
Oleg Nesterovf2cc3eb2008-02-08 04:19:06 -08001716
Roland McGrath98abed02008-03-19 19:24:59 -07001717 if (!retval && !(options & WNOHANG)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001718 retval = -ERESTARTSYS;
Roland McGrath98abed02008-03-19 19:24:59 -07001719 if (!signal_pending(current)) {
1720 schedule();
1721 goto repeat;
1722 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001723 }
Roland McGrath98abed02008-03-19 19:24:59 -07001724
Linus Torvalds1da177e2005-04-16 15:20:36 -07001725end:
1726 current->state = TASK_RUNNING;
1727 remove_wait_queue(&current->signal->wait_chldexit,&wait);
1728 if (infop) {
1729 if (retval > 0)
Oleg Nesterov9cbab812008-02-08 04:19:02 -08001730 retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731 else {
1732 /*
1733 * For a WNOHANG return, clear out all the fields
1734 * we would set so the user can easily tell the
1735 * difference.
1736 */
1737 if (!retval)
1738 retval = put_user(0, &infop->si_signo);
1739 if (!retval)
1740 retval = put_user(0, &infop->si_errno);
1741 if (!retval)
1742 retval = put_user(0, &infop->si_code);
1743 if (!retval)
1744 retval = put_user(0, &infop->si_pid);
1745 if (!retval)
1746 retval = put_user(0, &infop->si_uid);
1747 if (!retval)
1748 retval = put_user(0, &infop->si_status);
1749 }
1750 }
1751 return retval;
1752}
1753
Heiko Carstens17da2bd2009-01-14 14:14:10 +01001754SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
1755 infop, int, options, struct rusage __user *, ru)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756{
Eric W. Biederman161550d2008-02-08 04:19:14 -08001757 struct pid *pid = NULL;
1758 enum pid_type type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759 long ret;
1760
1761 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
1762 return -EINVAL;
1763 if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
1764 return -EINVAL;
1765
1766 switch (which) {
1767 case P_ALL:
Eric W. Biederman161550d2008-02-08 04:19:14 -08001768 type = PIDTYPE_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769 break;
1770 case P_PID:
Eric W. Biederman161550d2008-02-08 04:19:14 -08001771 type = PIDTYPE_PID;
1772 if (upid <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 return -EINVAL;
1774 break;
1775 case P_PGID:
Eric W. Biederman161550d2008-02-08 04:19:14 -08001776 type = PIDTYPE_PGID;
1777 if (upid <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779 break;
1780 default:
1781 return -EINVAL;
1782 }
1783
Eric W. Biederman161550d2008-02-08 04:19:14 -08001784 if (type < PIDTYPE_MAX)
1785 pid = find_get_pid(upid);
1786 ret = do_wait(type, pid, options, infop, NULL, ru);
1787 put_pid(pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788
1789 /* avoid REGPARM breakage on x86: */
Roland McGrath54a01512008-04-10 15:37:38 -07001790 asmlinkage_protect(5, ret, which, upid, infop, options, ru);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 return ret;
1792}
1793
Heiko Carstens754fe8d2009-01-14 14:14:09 +01001794SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
1795 int, options, struct rusage __user *, ru)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001796{
Eric W. Biederman161550d2008-02-08 04:19:14 -08001797 struct pid *pid = NULL;
1798 enum pid_type type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 long ret;
1800
1801 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
1802 __WNOTHREAD|__WCLONE|__WALL))
1803 return -EINVAL;
Eric W. Biederman161550d2008-02-08 04:19:14 -08001804
1805 if (upid == -1)
1806 type = PIDTYPE_MAX;
1807 else if (upid < 0) {
1808 type = PIDTYPE_PGID;
1809 pid = find_get_pid(-upid);
1810 } else if (upid == 0) {
1811 type = PIDTYPE_PGID;
1812 pid = get_pid(task_pgrp(current));
1813 } else /* upid > 0 */ {
1814 type = PIDTYPE_PID;
1815 pid = find_get_pid(upid);
1816 }
1817
1818 ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru);
1819 put_pid(pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820
1821 /* avoid REGPARM breakage on x86: */
Roland McGrath54a01512008-04-10 15:37:38 -07001822 asmlinkage_protect(4, ret, upid, stat_addr, options, ru);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001823 return ret;
1824}
1825
1826#ifdef __ARCH_WANT_SYS_WAITPID
1827
1828/*
1829 * sys_waitpid() remains for compatibility. waitpid() should be
1830 * implemented by calling sys_wait4() from libc.a.
1831 */
Heiko Carstens17da2bd2009-01-14 14:14:10 +01001832SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833{
1834 return sys_wait4(pid, stat_addr, options, NULL);
1835}
1836
1837#endif