Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/exit.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
1da177e4 LT |
7 | #include <linux/mm.h> |
8 | #include <linux/slab.h> | |
9 | #include <linux/interrupt.h> | |
1da177e4 | 10 | #include <linux/module.h> |
c59ede7b | 11 | #include <linux/capability.h> |
1da177e4 LT |
12 | #include <linux/completion.h> |
13 | #include <linux/personality.h> | |
14 | #include <linux/tty.h> | |
6b3286ed | 15 | #include <linux/mnt_namespace.h> |
da9cbc87 | 16 | #include <linux/iocontext.h> |
1da177e4 LT |
17 | #include <linux/key.h> |
18 | #include <linux/security.h> | |
19 | #include <linux/cpu.h> | |
20 | #include <linux/acct.h> | |
8f0ab514 | 21 | #include <linux/tsacct_kern.h> |
1da177e4 | 22 | #include <linux/file.h> |
9f3acc31 | 23 | #include <linux/fdtable.h> |
1da177e4 | 24 | #include <linux/binfmts.h> |
ab516013 | 25 | #include <linux/nsproxy.h> |
84d73786 | 26 | #include <linux/pid_namespace.h> |
1da177e4 LT |
27 | #include <linux/ptrace.h> |
28 | #include <linux/profile.h> | |
29 | #include <linux/mount.h> | |
30 | #include <linux/proc_fs.h> | |
49d769d5 | 31 | #include <linux/kthread.h> |
1da177e4 | 32 | #include <linux/mempolicy.h> |
c757249a | 33 | #include <linux/taskstats_kern.h> |
ca74e92b | 34 | #include <linux/delayacct.h> |
83144186 | 35 | #include <linux/freezer.h> |
b4f48b63 | 36 | #include <linux/cgroup.h> |
1da177e4 | 37 | #include <linux/syscalls.h> |
7ed20e1a | 38 | #include <linux/signal.h> |
6a14c5c9 | 39 | #include <linux/posix-timers.h> |
9f46080c | 40 | #include <linux/cn_proc.h> |
de5097c2 | 41 | #include <linux/mutex.h> |
0771dfef | 42 | #include <linux/futex.h> |
b92ce558 | 43 | #include <linux/pipe_fs_i.h> |
fa84cb93 | 44 | #include <linux/audit.h> /* for audit_free() */ |
83cc5ed3 | 45 | #include <linux/resource.h> |
0d67a46d | 46 | #include <linux/blkdev.h> |
6eaeeaba | 47 | #include <linux/task_io_accounting_ops.h> |
30199f5a | 48 | #include <linux/tracehook.h> |
d84f4f99 | 49 | #include <linux/init_task.h> |
0a16b607 | 50 | #include <trace/sched.h> |
1da177e4 LT |
51 | |
52 | #include <asm/uaccess.h> | |
53 | #include <asm/unistd.h> | |
54 | #include <asm/pgtable.h> | |
55 | #include <asm/mmu_context.h> | |
d84f4f99 | 56 | #include "cred-internals.h" |
1da177e4 | 57 | |
7e066fb8 MD |
58 | DEFINE_TRACE(sched_process_free); |
59 | DEFINE_TRACE(sched_process_exit); | |
60 | DEFINE_TRACE(sched_process_wait); | |
61 | ||
408b664a AB |
62 | static void exit_mm(struct task_struct * tsk); |
63 | ||
d839fd4d ON |
64 | static inline int task_detached(struct task_struct *p) |
65 | { | |
66 | return p->exit_signal == -1; | |
67 | } | |
68 | ||
1da177e4 LT |
69 | static void __unhash_process(struct task_struct *p) |
70 | { | |
71 | nr_threads--; | |
72 | detach_pid(p, PIDTYPE_PID); | |
1da177e4 LT |
73 | if (thread_group_leader(p)) { |
74 | detach_pid(p, PIDTYPE_PGID); | |
75 | detach_pid(p, PIDTYPE_SID); | |
c97d9893 | 76 | |
5e85d4ab | 77 | list_del_rcu(&p->tasks); |
73b9ebfe | 78 | __get_cpu_var(process_counts)--; |
1da177e4 | 79 | } |
47e65328 | 80 | list_del_rcu(&p->thread_group); |
f470021a | 81 | list_del_init(&p->sibling); |
1da177e4 LT |
82 | } |
83 | ||
6a14c5c9 ON |
84 | /* |
85 | * This function expects the tasklist_lock write-locked. | |
86 | */ | |
87 | static 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 | ||
6a14c5c9 ON |
95 | 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 | */ | |
6db840fa | 106 | if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) |
6a14c5c9 | 107 | wake_up_process(sig->group_exit_task); |
6db840fa | 108 | |
6a14c5c9 ON |
109 | 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 | */ | |
49048622 | 121 | sig->gtime = cputime_add(sig->gtime, task_gtime(tsk)); |
6a14c5c9 ON |
122 | sig->min_flt += tsk->min_flt; |
123 | sig->maj_flt += tsk->maj_flt; | |
124 | sig->nvcsw += tsk->nvcsw; | |
125 | sig->nivcsw += tsk->nivcsw; | |
6eaeeaba ED |
126 | sig->inblock += task_io_get_inblock(tsk); |
127 | sig->oublock += task_io_get_oublock(tsk); | |
5995477a | 128 | task_io_accounting_add(&sig->ioac, &tsk->ioac); |
6a14c5c9 ON |
129 | sig = NULL; /* Marker for below. */ |
130 | } | |
131 | ||
5876700c ON |
132 | __unhash_process(tsk); |
133 | ||
da7978b0 ON |
134 | /* |
135 | * Do this under ->siglock, we can race with another thread | |
136 | * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals. | |
137 | */ | |
138 | flush_sigqueue(&tsk->pending); | |
139 | ||
6a14c5c9 | 140 | tsk->signal = NULL; |
a7e5328a | 141 | tsk->sighand = NULL; |
6a14c5c9 | 142 | spin_unlock(&sighand->siglock); |
6a14c5c9 | 143 | |
a7e5328a | 144 | __cleanup_sighand(sighand); |
6a14c5c9 | 145 | clear_tsk_thread_flag(tsk,TIF_SIGPENDING); |
6a14c5c9 ON |
146 | if (sig) { |
147 | flush_sigqueue(&sig->shared_pending); | |
093a8e8a | 148 | taskstats_tgid_free(sig); |
ad474cac ON |
149 | /* |
150 | * Make sure ->signal can't go away under rq->lock, | |
151 | * see account_group_exec_runtime(). | |
152 | */ | |
153 | task_rq_unlock_wait(tsk); | |
6a14c5c9 ON |
154 | __cleanup_signal(sig); |
155 | } | |
156 | } | |
157 | ||
8c7904a0 EB |
158 | static void delayed_put_task_struct(struct rcu_head *rhp) |
159 | { | |
0a16b607 MD |
160 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); |
161 | ||
162 | trace_sched_process_free(tsk); | |
163 | put_task_struct(tsk); | |
8c7904a0 EB |
164 | } |
165 | ||
f470021a | 166 | |
1da177e4 LT |
167 | void release_task(struct task_struct * p) |
168 | { | |
36c8b586 | 169 | struct task_struct *leader; |
1da177e4 | 170 | int zap_leader; |
1f09f974 | 171 | repeat: |
dae33574 | 172 | tracehook_prepare_release_task(p); |
c69e8d9c DH |
173 | /* don't need to get the RCU readlock here - the process is dead and |
174 | * can't be modifying its own credentials */ | |
175 | atomic_dec(&__task_cred(p)->user->processes); | |
176 | ||
60347f67 | 177 | proc_flush_task(p); |
1da177e4 | 178 | write_lock_irq(&tasklist_lock); |
dae33574 | 179 | tracehook_finish_release_task(p); |
1da177e4 | 180 | __exit_signal(p); |
35f5cad8 | 181 | |
1da177e4 LT |
182 | /* |
183 | * If we are the last non-leader member of the thread | |
184 | * group, and the leader is zombie, then notify the | |
185 | * group leader's parent process. (if it wants notification.) | |
186 | */ | |
187 | zap_leader = 0; | |
188 | leader = p->group_leader; | |
189 | if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) { | |
d839fd4d | 190 | BUG_ON(task_detached(leader)); |
1da177e4 LT |
191 | do_notify_parent(leader, leader->exit_signal); |
192 | /* | |
193 | * If we were the last child thread and the leader has | |
194 | * exited already, and the leader's parent ignores SIGCHLD, | |
195 | * then we are the one who should release the leader. | |
196 | * | |
197 | * do_notify_parent() will have marked it self-reaping in | |
198 | * that case. | |
199 | */ | |
d839fd4d | 200 | zap_leader = task_detached(leader); |
dae33574 RM |
201 | |
202 | /* | |
203 | * This maintains the invariant that release_task() | |
204 | * only runs on a task in EXIT_DEAD, just for sanity. | |
205 | */ | |
206 | if (zap_leader) | |
207 | leader->exit_state = EXIT_DEAD; | |
1da177e4 LT |
208 | } |
209 | ||
1da177e4 | 210 | write_unlock_irq(&tasklist_lock); |
1da177e4 | 211 | release_thread(p); |
8c7904a0 | 212 | call_rcu(&p->rcu, delayed_put_task_struct); |
1da177e4 LT |
213 | |
214 | p = leader; | |
215 | if (unlikely(zap_leader)) | |
216 | goto repeat; | |
217 | } | |
218 | ||
1da177e4 LT |
219 | /* |
220 | * This checks not only the pgrp, but falls back on the pid if no | |
221 | * satisfactory pgrp is found. I dunno - gdb doesn't work correctly | |
222 | * without this... | |
04a2e6a5 EB |
223 | * |
224 | * The caller must hold rcu lock or the tasklist lock. | |
1da177e4 | 225 | */ |
04a2e6a5 | 226 | struct pid *session_of_pgrp(struct pid *pgrp) |
1da177e4 LT |
227 | { |
228 | struct task_struct *p; | |
04a2e6a5 | 229 | struct pid *sid = NULL; |
62dfb554 | 230 | |
04a2e6a5 | 231 | p = pid_task(pgrp, PIDTYPE_PGID); |
62dfb554 | 232 | if (p == NULL) |
04a2e6a5 | 233 | p = pid_task(pgrp, PIDTYPE_PID); |
62dfb554 | 234 | if (p != NULL) |
04a2e6a5 | 235 | sid = task_session(p); |
62dfb554 | 236 | |
1da177e4 LT |
237 | return sid; |
238 | } | |
239 | ||
240 | /* | |
241 | * Determine if a process group is "orphaned", according to the POSIX | |
242 | * definition in 2.2.2.52. Orphaned process groups are not to be affected | |
243 | * by terminal-generated stop signals. Newly orphaned process groups are | |
244 | * to receive a SIGHUP and a SIGCONT. | |
245 | * | |
246 | * "I ask you, have you ever known what it is to be an orphan?" | |
247 | */ | |
0475ac08 | 248 | static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task) |
1da177e4 LT |
249 | { |
250 | struct task_struct *p; | |
1da177e4 | 251 | |
0475ac08 | 252 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
05e83df6 ON |
253 | if ((p == ignored_task) || |
254 | (p->exit_state && thread_group_empty(p)) || | |
255 | is_global_init(p->real_parent)) | |
1da177e4 | 256 | continue; |
05e83df6 | 257 | |
0475ac08 | 258 | if (task_pgrp(p->real_parent) != pgrp && |
05e83df6 ON |
259 | task_session(p->real_parent) == task_session(p)) |
260 | return 0; | |
0475ac08 | 261 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
05e83df6 ON |
262 | |
263 | return 1; | |
1da177e4 LT |
264 | } |
265 | ||
3e7cd6c4 | 266 | int is_current_pgrp_orphaned(void) |
1da177e4 LT |
267 | { |
268 | int retval; | |
269 | ||
270 | read_lock(&tasklist_lock); | |
3e7cd6c4 | 271 | retval = will_become_orphaned_pgrp(task_pgrp(current), NULL); |
1da177e4 LT |
272 | read_unlock(&tasklist_lock); |
273 | ||
274 | return retval; | |
275 | } | |
276 | ||
0475ac08 | 277 | static int has_stopped_jobs(struct pid *pgrp) |
1da177e4 LT |
278 | { |
279 | int retval = 0; | |
280 | struct task_struct *p; | |
281 | ||
0475ac08 | 282 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
338077e5 | 283 | if (!task_is_stopped(p)) |
1da177e4 | 284 | continue; |
1da177e4 LT |
285 | retval = 1; |
286 | break; | |
0475ac08 | 287 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
288 | return retval; |
289 | } | |
290 | ||
f49ee505 ON |
291 | /* |
292 | * Check to see if any process groups have become orphaned as | |
293 | * a result of our exiting, and if they have any stopped jobs, | |
294 | * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) | |
295 | */ | |
296 | static void | |
297 | kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) | |
298 | { | |
299 | struct pid *pgrp = task_pgrp(tsk); | |
300 | struct task_struct *ignored_task = tsk; | |
301 | ||
302 | if (!parent) | |
303 | /* exit: our father is in a different pgrp than | |
304 | * we are and we were the only connection outside. | |
305 | */ | |
306 | parent = tsk->real_parent; | |
307 | else | |
308 | /* reparent: our child is in a different pgrp than | |
309 | * we are, and it was the only connection outside. | |
310 | */ | |
311 | ignored_task = NULL; | |
312 | ||
313 | if (task_pgrp(parent) != pgrp && | |
314 | task_session(parent) == task_session(tsk) && | |
315 | will_become_orphaned_pgrp(pgrp, ignored_task) && | |
316 | has_stopped_jobs(pgrp)) { | |
317 | __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp); | |
318 | __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp); | |
319 | } | |
320 | } | |
321 | ||
1da177e4 | 322 | /** |
49d769d5 | 323 | * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd |
1da177e4 LT |
324 | * |
325 | * If a kernel thread is launched as a result of a system call, or if | |
49d769d5 EB |
326 | * it ever exits, it should generally reparent itself to kthreadd so it |
327 | * isn't in the way of other processes and is correctly cleaned up on exit. | |
1da177e4 LT |
328 | * |
329 | * The various task state such as scheduling policy and priority may have | |
330 | * been inherited from a user process, so we reset them to sane values here. | |
331 | * | |
49d769d5 | 332 | * NOTE that reparent_to_kthreadd() gives the caller full capabilities. |
1da177e4 | 333 | */ |
49d769d5 | 334 | static void reparent_to_kthreadd(void) |
1da177e4 LT |
335 | { |
336 | write_lock_irq(&tasklist_lock); | |
337 | ||
338 | ptrace_unlink(current); | |
339 | /* Reparent to init */ | |
49d769d5 | 340 | current->real_parent = current->parent = kthreadd_task; |
f470021a | 341 | list_move_tail(¤t->sibling, ¤t->real_parent->children); |
1da177e4 LT |
342 | |
343 | /* Set the exit signal to SIGCHLD so we signal init on exit */ | |
344 | current->exit_signal = SIGCHLD; | |
345 | ||
e05606d3 | 346 | if (task_nice(current) < 0) |
1da177e4 LT |
347 | set_user_nice(current, 0); |
348 | /* cpus_allowed? */ | |
349 | /* rt_priority? */ | |
350 | /* signals? */ | |
1da177e4 LT |
351 | memcpy(current->signal->rlim, init_task.signal->rlim, |
352 | sizeof(current->signal->rlim)); | |
d84f4f99 DH |
353 | |
354 | atomic_inc(&init_cred.usage); | |
355 | commit_creds(&init_cred); | |
1da177e4 | 356 | write_unlock_irq(&tasklist_lock); |
1da177e4 LT |
357 | } |
358 | ||
8520d7c7 | 359 | void __set_special_pids(struct pid *pid) |
1da177e4 | 360 | { |
e19f247a | 361 | struct task_struct *curr = current->group_leader; |
8520d7c7 | 362 | pid_t nr = pid_nr(pid); |
1da177e4 | 363 | |
8520d7c7 | 364 | if (task_session(curr) != pid) { |
7d8da096 | 365 | change_pid(curr, PIDTYPE_SID, pid); |
8520d7c7 | 366 | set_task_session(curr, nr); |
1da177e4 | 367 | } |
8520d7c7 | 368 | if (task_pgrp(curr) != pid) { |
7d8da096 | 369 | change_pid(curr, PIDTYPE_PGID, pid); |
8520d7c7 | 370 | set_task_pgrp(curr, nr); |
1da177e4 LT |
371 | } |
372 | } | |
373 | ||
8520d7c7 | 374 | static void set_special_pids(struct pid *pid) |
1da177e4 LT |
375 | { |
376 | write_lock_irq(&tasklist_lock); | |
8520d7c7 | 377 | __set_special_pids(pid); |
1da177e4 LT |
378 | write_unlock_irq(&tasklist_lock); |
379 | } | |
380 | ||
381 | /* | |
382 | * Let kernel threads use this to say that they | |
383 | * allow a certain signal (since daemonize() will | |
384 | * have disabled all of them by default). | |
385 | */ | |
386 | int allow_signal(int sig) | |
387 | { | |
7ed20e1a | 388 | if (!valid_signal(sig) || sig < 1) |
1da177e4 LT |
389 | return -EINVAL; |
390 | ||
391 | spin_lock_irq(¤t->sighand->siglock); | |
392 | sigdelset(¤t->blocked, sig); | |
393 | if (!current->mm) { | |
394 | /* Kernel threads handle their own signals. | |
395 | Let the signal code know it'll be handled, so | |
396 | that they don't get converted to SIGKILL or | |
397 | just silently dropped */ | |
398 | current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; | |
399 | } | |
400 | recalc_sigpending(); | |
401 | spin_unlock_irq(¤t->sighand->siglock); | |
402 | return 0; | |
403 | } | |
404 | ||
405 | EXPORT_SYMBOL(allow_signal); | |
406 | ||
407 | int disallow_signal(int sig) | |
408 | { | |
7ed20e1a | 409 | if (!valid_signal(sig) || sig < 1) |
1da177e4 LT |
410 | return -EINVAL; |
411 | ||
412 | spin_lock_irq(¤t->sighand->siglock); | |
10ab825b | 413 | current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; |
1da177e4 LT |
414 | recalc_sigpending(); |
415 | spin_unlock_irq(¤t->sighand->siglock); | |
416 | return 0; | |
417 | } | |
418 | ||
419 | EXPORT_SYMBOL(disallow_signal); | |
420 | ||
421 | /* | |
422 | * Put all the gunge required to become a kernel thread without | |
423 | * attached user resources in one place where it belongs. | |
424 | */ | |
425 | ||
426 | void daemonize(const char *name, ...) | |
427 | { | |
428 | va_list args; | |
429 | struct fs_struct *fs; | |
430 | sigset_t blocked; | |
431 | ||
432 | va_start(args, name); | |
433 | vsnprintf(current->comm, sizeof(current->comm), name, args); | |
434 | va_end(args); | |
435 | ||
436 | /* | |
437 | * If we were started as result of loading a module, close all of the | |
438 | * user space pages. We don't need them, and if we didn't close them | |
439 | * they would be locked into memory. | |
440 | */ | |
441 | exit_mm(current); | |
83144186 RW |
442 | /* |
443 | * We don't want to have TIF_FREEZE set if the system-wide hibernation | |
444 | * or suspend transition begins right now. | |
445 | */ | |
7b34e428 | 446 | current->flags |= (PF_NOFREEZE | PF_KTHREAD); |
1da177e4 | 447 | |
8520d7c7 ON |
448 | if (current->nsproxy != &init_nsproxy) { |
449 | get_nsproxy(&init_nsproxy); | |
450 | switch_task_namespaces(current, &init_nsproxy); | |
451 | } | |
297bd42b | 452 | set_special_pids(&init_struct_pid); |
24ec839c | 453 | proc_clear_tty(current); |
1da177e4 LT |
454 | |
455 | /* Block and flush all signals */ | |
456 | sigfillset(&blocked); | |
457 | sigprocmask(SIG_BLOCK, &blocked, NULL); | |
458 | flush_signals(current); | |
459 | ||
460 | /* Become as one with the init task */ | |
461 | ||
462 | exit_fs(current); /* current->fs->count--; */ | |
463 | fs = init_task.fs; | |
464 | current->fs = fs; | |
465 | atomic_inc(&fs->count); | |
ab516013 | 466 | |
d4c5e41f | 467 | exit_files(current); |
1da177e4 LT |
468 | current->files = init_task.files; |
469 | atomic_inc(¤t->files->count); | |
470 | ||
49d769d5 | 471 | reparent_to_kthreadd(); |
1da177e4 LT |
472 | } |
473 | ||
474 | EXPORT_SYMBOL(daemonize); | |
475 | ||
858119e1 | 476 | static void close_files(struct files_struct * files) |
1da177e4 LT |
477 | { |
478 | int i, j; | |
badf1662 | 479 | struct fdtable *fdt; |
1da177e4 LT |
480 | |
481 | j = 0; | |
4fb3a538 DS |
482 | |
483 | /* | |
484 | * It is safe to dereference the fd table without RCU or | |
485 | * ->file_lock because this is the last reference to the | |
486 | * files structure. | |
487 | */ | |
badf1662 | 488 | fdt = files_fdtable(files); |
1da177e4 LT |
489 | for (;;) { |
490 | unsigned long set; | |
491 | i = j * __NFDBITS; | |
bbea9f69 | 492 | if (i >= fdt->max_fds) |
1da177e4 | 493 | break; |
badf1662 | 494 | set = fdt->open_fds->fds_bits[j++]; |
1da177e4 LT |
495 | while (set) { |
496 | if (set & 1) { | |
badf1662 | 497 | struct file * file = xchg(&fdt->fd[i], NULL); |
944be0b2 | 498 | if (file) { |
1da177e4 | 499 | filp_close(file, files); |
944be0b2 IM |
500 | cond_resched(); |
501 | } | |
1da177e4 LT |
502 | } |
503 | i++; | |
504 | set >>= 1; | |
505 | } | |
506 | } | |
507 | } | |
508 | ||
509 | struct files_struct *get_files_struct(struct task_struct *task) | |
510 | { | |
511 | struct files_struct *files; | |
512 | ||
513 | task_lock(task); | |
514 | files = task->files; | |
515 | if (files) | |
516 | atomic_inc(&files->count); | |
517 | task_unlock(task); | |
518 | ||
519 | return files; | |
520 | } | |
521 | ||
7ad5b3a5 | 522 | void put_files_struct(struct files_struct *files) |
1da177e4 | 523 | { |
badf1662 DS |
524 | struct fdtable *fdt; |
525 | ||
1da177e4 LT |
526 | if (atomic_dec_and_test(&files->count)) { |
527 | close_files(files); | |
528 | /* | |
529 | * Free the fd and fdset arrays if we expanded them. | |
ab2af1f5 DS |
530 | * If the fdtable was embedded, pass files for freeing |
531 | * at the end of the RCU grace period. Otherwise, | |
532 | * you can free files immediately. | |
1da177e4 | 533 | */ |
badf1662 | 534 | fdt = files_fdtable(files); |
4fd45812 | 535 | if (fdt != &files->fdtab) |
ab2af1f5 | 536 | kmem_cache_free(files_cachep, files); |
01b2d93c | 537 | free_fdtable(fdt); |
1da177e4 LT |
538 | } |
539 | } | |
540 | ||
3b125388 | 541 | void reset_files_struct(struct files_struct *files) |
3b9b8ab6 | 542 | { |
3b125388 | 543 | struct task_struct *tsk = current; |
3b9b8ab6 KK |
544 | struct files_struct *old; |
545 | ||
546 | old = tsk->files; | |
547 | task_lock(tsk); | |
548 | tsk->files = files; | |
549 | task_unlock(tsk); | |
550 | put_files_struct(old); | |
551 | } | |
3b9b8ab6 | 552 | |
1ec7f1dd | 553 | void exit_files(struct task_struct *tsk) |
1da177e4 LT |
554 | { |
555 | struct files_struct * files = tsk->files; | |
556 | ||
557 | if (files) { | |
558 | task_lock(tsk); | |
559 | tsk->files = NULL; | |
560 | task_unlock(tsk); | |
561 | put_files_struct(files); | |
562 | } | |
563 | } | |
564 | ||
1ec7f1dd | 565 | void put_fs_struct(struct fs_struct *fs) |
1da177e4 LT |
566 | { |
567 | /* No need to hold fs->lock if we are killing it */ | |
568 | if (atomic_dec_and_test(&fs->count)) { | |
6ac08c39 JB |
569 | path_put(&fs->root); |
570 | path_put(&fs->pwd); | |
1da177e4 LT |
571 | kmem_cache_free(fs_cachep, fs); |
572 | } | |
573 | } | |
574 | ||
1ec7f1dd | 575 | void exit_fs(struct task_struct *tsk) |
1da177e4 LT |
576 | { |
577 | struct fs_struct * fs = tsk->fs; | |
578 | ||
579 | if (fs) { | |
580 | task_lock(tsk); | |
581 | tsk->fs = NULL; | |
582 | task_unlock(tsk); | |
1ec7f1dd | 583 | put_fs_struct(fs); |
1da177e4 LT |
584 | } |
585 | } | |
586 | ||
1da177e4 LT |
587 | EXPORT_SYMBOL_GPL(exit_fs); |
588 | ||
cf475ad2 BS |
589 | #ifdef CONFIG_MM_OWNER |
590 | /* | |
591 | * Task p is exiting and it owned mm, lets find a new owner for it | |
592 | */ | |
593 | static inline int | |
594 | mm_need_new_owner(struct mm_struct *mm, struct task_struct *p) | |
595 | { | |
596 | /* | |
597 | * If there are other users of the mm and the owner (us) is exiting | |
598 | * we need to find a new owner to take on the responsibility. | |
599 | */ | |
cf475ad2 BS |
600 | if (atomic_read(&mm->mm_users) <= 1) |
601 | return 0; | |
602 | if (mm->owner != p) | |
603 | return 0; | |
604 | return 1; | |
605 | } | |
606 | ||
607 | void mm_update_next_owner(struct mm_struct *mm) | |
608 | { | |
609 | struct task_struct *c, *g, *p = current; | |
610 | ||
611 | retry: | |
612 | if (!mm_need_new_owner(mm, p)) | |
613 | return; | |
614 | ||
615 | read_lock(&tasklist_lock); | |
616 | /* | |
617 | * Search in the children | |
618 | */ | |
619 | list_for_each_entry(c, &p->children, sibling) { | |
620 | if (c->mm == mm) | |
621 | goto assign_new_owner; | |
622 | } | |
623 | ||
624 | /* | |
625 | * Search in the siblings | |
626 | */ | |
627 | list_for_each_entry(c, &p->parent->children, sibling) { | |
628 | if (c->mm == mm) | |
629 | goto assign_new_owner; | |
630 | } | |
631 | ||
632 | /* | |
633 | * Search through everything else. We should not get | |
634 | * here often | |
635 | */ | |
636 | do_each_thread(g, c) { | |
637 | if (c->mm == mm) | |
638 | goto assign_new_owner; | |
639 | } while_each_thread(g, c); | |
640 | ||
641 | read_unlock(&tasklist_lock); | |
31a78f23 BS |
642 | /* |
643 | * We found no owner yet mm_users > 1: this implies that we are | |
644 | * most likely racing with swapoff (try_to_unuse()) or /proc or | |
e5991371 | 645 | * ptrace or page migration (get_task_mm()). Mark owner as NULL. |
31a78f23 | 646 | */ |
31a78f23 | 647 | mm->owner = NULL; |
cf475ad2 BS |
648 | return; |
649 | ||
650 | assign_new_owner: | |
651 | BUG_ON(c == p); | |
652 | get_task_struct(c); | |
653 | /* | |
654 | * The task_lock protects c->mm from changing. | |
655 | * We always want mm->owner->mm == mm | |
656 | */ | |
657 | task_lock(c); | |
e5991371 HD |
658 | /* |
659 | * Delay read_unlock() till we have the task_lock() | |
660 | * to ensure that c does not slip away underneath us | |
661 | */ | |
662 | read_unlock(&tasklist_lock); | |
cf475ad2 BS |
663 | if (c->mm != mm) { |
664 | task_unlock(c); | |
665 | put_task_struct(c); | |
666 | goto retry; | |
667 | } | |
cf475ad2 BS |
668 | mm->owner = c; |
669 | task_unlock(c); | |
670 | put_task_struct(c); | |
671 | } | |
672 | #endif /* CONFIG_MM_OWNER */ | |
673 | ||
1da177e4 LT |
674 | /* |
675 | * Turn us into a lazy TLB process if we | |
676 | * aren't already.. | |
677 | */ | |
408b664a | 678 | static void exit_mm(struct task_struct * tsk) |
1da177e4 LT |
679 | { |
680 | struct mm_struct *mm = tsk->mm; | |
b564daf8 | 681 | struct core_state *core_state; |
1da177e4 LT |
682 | |
683 | mm_release(tsk, mm); | |
684 | if (!mm) | |
685 | return; | |
686 | /* | |
687 | * Serialize with any possible pending coredump. | |
999d9fc1 | 688 | * We must hold mmap_sem around checking core_state |
1da177e4 | 689 | * and clearing tsk->mm. The core-inducing thread |
999d9fc1 | 690 | * will increment ->nr_threads for each thread in the |
1da177e4 LT |
691 | * group with ->mm != NULL. |
692 | */ | |
693 | down_read(&mm->mmap_sem); | |
b564daf8 ON |
694 | core_state = mm->core_state; |
695 | if (core_state) { | |
696 | struct core_thread self; | |
1da177e4 | 697 | up_read(&mm->mmap_sem); |
c5f1cc8c | 698 | |
b564daf8 ON |
699 | self.task = tsk; |
700 | self.next = xchg(&core_state->dumper.next, &self); | |
701 | /* | |
702 | * Implies mb(), the result of xchg() must be visible | |
703 | * to core_state->dumper. | |
704 | */ | |
705 | if (atomic_dec_and_test(&core_state->nr_threads)) | |
706 | complete(&core_state->startup); | |
1da177e4 | 707 | |
a94e2d40 ON |
708 | for (;;) { |
709 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); | |
710 | if (!self.task) /* see coredump_finish() */ | |
711 | break; | |
712 | schedule(); | |
713 | } | |
714 | __set_task_state(tsk, TASK_RUNNING); | |
1da177e4 LT |
715 | down_read(&mm->mmap_sem); |
716 | } | |
717 | atomic_inc(&mm->mm_count); | |
125e1874 | 718 | BUG_ON(mm != tsk->active_mm); |
1da177e4 LT |
719 | /* more a memory barrier than a real lock */ |
720 | task_lock(tsk); | |
721 | tsk->mm = NULL; | |
722 | up_read(&mm->mmap_sem); | |
723 | enter_lazy_tlb(mm, current); | |
0c1eecfb RW |
724 | /* We don't want this task to be frozen prematurely */ |
725 | clear_freeze_flag(tsk); | |
1da177e4 | 726 | task_unlock(tsk); |
cf475ad2 | 727 | mm_update_next_owner(mm); |
1da177e4 LT |
728 | mmput(mm); |
729 | } | |
730 | ||
666f164f RM |
731 | /* |
732 | * Return nonzero if @parent's children should reap themselves. | |
733 | * | |
734 | * Called with write_lock_irq(&tasklist_lock) held. | |
735 | */ | |
736 | static int ignoring_children(struct task_struct *parent) | |
737 | { | |
738 | int ret; | |
739 | struct sighand_struct *psig = parent->sighand; | |
740 | unsigned long flags; | |
741 | spin_lock_irqsave(&psig->siglock, flags); | |
742 | ret = (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || | |
743 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT)); | |
744 | spin_unlock_irqrestore(&psig->siglock, flags); | |
745 | return ret; | |
746 | } | |
747 | ||
f470021a RM |
748 | /* |
749 | * Detach all tasks we were using ptrace on. | |
750 | * Any that need to be release_task'd are put on the @dead list. | |
751 | * | |
752 | * Called with write_lock(&tasklist_lock) held. | |
753 | */ | |
754 | static void ptrace_exit(struct task_struct *parent, struct list_head *dead) | |
1da177e4 | 755 | { |
f470021a | 756 | struct task_struct *p, *n; |
666f164f | 757 | int ign = -1; |
241ceee0 | 758 | |
f470021a RM |
759 | list_for_each_entry_safe(p, n, &parent->ptraced, ptrace_entry) { |
760 | __ptrace_unlink(p); | |
761 | ||
762 | if (p->exit_state != EXIT_ZOMBIE) | |
763 | continue; | |
764 | ||
765 | /* | |
766 | * If it's a zombie, our attachedness prevented normal | |
767 | * parent notification or self-reaping. Do notification | |
768 | * now if it would have happened earlier. If it should | |
769 | * reap itself, add it to the @dead list. We can't call | |
770 | * release_task() here because we already hold tasklist_lock. | |
771 | * | |
772 | * If it's our own child, there is no notification to do. | |
666f164f RM |
773 | * But if our normal children self-reap, then this child |
774 | * was prevented by ptrace and we must reap it now. | |
1da177e4 | 775 | */ |
f470021a RM |
776 | if (!task_detached(p) && thread_group_empty(p)) { |
777 | if (!same_thread_group(p->real_parent, parent)) | |
778 | do_notify_parent(p, p->exit_signal); | |
666f164f RM |
779 | else { |
780 | if (ign < 0) | |
781 | ign = ignoring_children(parent); | |
782 | if (ign) | |
783 | p->exit_signal = -1; | |
784 | } | |
f470021a | 785 | } |
1da177e4 | 786 | |
f470021a | 787 | if (task_detached(p)) { |
1da177e4 | 788 | /* |
f470021a | 789 | * Mark it as in the process of being reaped. |
1da177e4 | 790 | */ |
f470021a RM |
791 | p->exit_state = EXIT_DEAD; |
792 | list_add(&p->ptrace_entry, dead); | |
1da177e4 LT |
793 | } |
794 | } | |
f470021a RM |
795 | } |
796 | ||
797 | /* | |
798 | * Finish up exit-time ptrace cleanup. | |
799 | * | |
800 | * Called without locks. | |
801 | */ | |
802 | static void ptrace_exit_finish(struct task_struct *parent, | |
803 | struct list_head *dead) | |
804 | { | |
805 | struct task_struct *p, *n; | |
806 | ||
807 | BUG_ON(!list_empty(&parent->ptraced)); | |
808 | ||
809 | list_for_each_entry_safe(p, n, dead, ptrace_entry) { | |
810 | list_del_init(&p->ptrace_entry); | |
811 | release_task(p); | |
812 | } | |
813 | } | |
814 | ||
815 | static void reparent_thread(struct task_struct *p, struct task_struct *father) | |
816 | { | |
817 | if (p->pdeath_signal) | |
818 | /* We already hold the tasklist_lock here. */ | |
819 | group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p); | |
820 | ||
821 | list_move_tail(&p->sibling, &p->real_parent->children); | |
1da177e4 | 822 | |
b2b2cbc4 EB |
823 | /* If this is a threaded reparent there is no need to |
824 | * notify anyone anything has happened. | |
825 | */ | |
376e1d25 | 826 | if (same_thread_group(p->real_parent, father)) |
b2b2cbc4 EB |
827 | return; |
828 | ||
829 | /* We don't want people slaying init. */ | |
d839fd4d | 830 | if (!task_detached(p)) |
b2b2cbc4 | 831 | p->exit_signal = SIGCHLD; |
b2b2cbc4 EB |
832 | |
833 | /* If we'd notified the old parent about this child's death, | |
834 | * also notify the new parent. | |
835 | */ | |
f470021a RM |
836 | if (!ptrace_reparented(p) && |
837 | p->exit_state == EXIT_ZOMBIE && | |
d839fd4d | 838 | !task_detached(p) && thread_group_empty(p)) |
b2b2cbc4 EB |
839 | do_notify_parent(p, p->exit_signal); |
840 | ||
f49ee505 | 841 | kill_orphaned_pgrp(p, father); |
1da177e4 LT |
842 | } |
843 | ||
844 | /* | |
845 | * When we die, we re-parent all our children. | |
846 | * Try to give them to another thread in our thread | |
847 | * group, and if no such member exists, give it to | |
84d73786 SB |
848 | * the child reaper process (ie "init") in our pid |
849 | * space. | |
1da177e4 | 850 | */ |
950bbabb ON |
851 | static struct task_struct *find_new_reaper(struct task_struct *father) |
852 | { | |
853 | struct pid_namespace *pid_ns = task_active_pid_ns(father); | |
854 | struct task_struct *thread; | |
855 | ||
856 | thread = father; | |
857 | while_each_thread(father, thread) { | |
858 | if (thread->flags & PF_EXITING) | |
859 | continue; | |
860 | if (unlikely(pid_ns->child_reaper == father)) | |
861 | pid_ns->child_reaper = thread; | |
862 | return thread; | |
863 | } | |
864 | ||
865 | if (unlikely(pid_ns->child_reaper == father)) { | |
866 | write_unlock_irq(&tasklist_lock); | |
867 | if (unlikely(pid_ns == &init_pid_ns)) | |
868 | panic("Attempted to kill init!"); | |
869 | ||
870 | zap_pid_ns_processes(pid_ns); | |
871 | write_lock_irq(&tasklist_lock); | |
872 | /* | |
873 | * We can not clear ->child_reaper or leave it alone. | |
874 | * There may by stealth EXIT_DEAD tasks on ->children, | |
875 | * forget_original_parent() must move them somewhere. | |
876 | */ | |
877 | pid_ns->child_reaper = init_pid_ns.child_reaper; | |
878 | } | |
879 | ||
880 | return pid_ns->child_reaper; | |
881 | } | |
882 | ||
762a24be | 883 | static void forget_original_parent(struct task_struct *father) |
1da177e4 | 884 | { |
950bbabb | 885 | struct task_struct *p, *n, *reaper; |
f470021a | 886 | LIST_HEAD(ptrace_dead); |
762a24be ON |
887 | |
888 | write_lock_irq(&tasklist_lock); | |
950bbabb | 889 | reaper = find_new_reaper(father); |
f470021a RM |
890 | /* |
891 | * First clean up ptrace if we were using it. | |
892 | */ | |
893 | ptrace_exit(father, &ptrace_dead); | |
894 | ||
03ff1797 | 895 | list_for_each_entry_safe(p, n, &father->children, sibling) { |
84eb646b | 896 | p->real_parent = reaper; |
f470021a RM |
897 | if (p->parent == father) { |
898 | BUG_ON(p->ptrace); | |
899 | p->parent = p->real_parent; | |
900 | } | |
901 | reparent_thread(p, father); | |
1da177e4 | 902 | } |
762a24be ON |
903 | |
904 | write_unlock_irq(&tasklist_lock); | |
905 | BUG_ON(!list_empty(&father->children)); | |
762a24be | 906 | |
f470021a | 907 | ptrace_exit_finish(father, &ptrace_dead); |
1da177e4 LT |
908 | } |
909 | ||
910 | /* | |
911 | * Send signals to all our closest relatives so that they know | |
912 | * to properly mourn us.. | |
913 | */ | |
821c7de7 | 914 | static void exit_notify(struct task_struct *tsk, int group_dead) |
1da177e4 | 915 | { |
2b2a1ff6 RM |
916 | int signal; |
917 | void *cookie; | |
1da177e4 | 918 | |
1da177e4 LT |
919 | /* |
920 | * This does two things: | |
921 | * | |
922 | * A. Make init inherit all the child processes | |
923 | * B. Check to see if any process groups have become orphaned | |
924 | * as a result of our exiting, and if they have any stopped | |
925 | * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) | |
926 | */ | |
762a24be | 927 | forget_original_parent(tsk); |
2e4a7072 | 928 | exit_task_namespaces(tsk); |
1da177e4 | 929 | |
762a24be | 930 | write_lock_irq(&tasklist_lock); |
821c7de7 ON |
931 | if (group_dead) |
932 | kill_orphaned_pgrp(tsk->group_leader, NULL); | |
1da177e4 | 933 | |
24728448 | 934 | /* Let father know we died |
1da177e4 LT |
935 | * |
936 | * Thread signals are configurable, but you aren't going to use | |
d4c5e41f | 937 | * that to send signals to arbitary processes. |
1da177e4 LT |
938 | * That stops right now. |
939 | * | |
940 | * If the parent exec id doesn't match the exec id we saved | |
941 | * when we started then we know the parent has changed security | |
942 | * domain. | |
943 | * | |
944 | * If our self_exec id doesn't match our parent_exec_id then | |
945 | * we have changed execution domain as these two values started | |
946 | * the same after a fork. | |
1da177e4 | 947 | */ |
d839fd4d | 948 | if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) && |
f49ee505 | 949 | (tsk->parent_exec_id != tsk->real_parent->self_exec_id || |
d839fd4d ON |
950 | tsk->self_exec_id != tsk->parent_exec_id) && |
951 | !capable(CAP_KILL)) | |
1da177e4 LT |
952 | tsk->exit_signal = SIGCHLD; |
953 | ||
2b2a1ff6 | 954 | signal = tracehook_notify_death(tsk, &cookie, group_dead); |
5c7edcd7 | 955 | if (signal >= 0) |
2b2a1ff6 | 956 | signal = do_notify_parent(tsk, signal); |
1da177e4 | 957 | |
5c7edcd7 | 958 | tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE; |
1da177e4 | 959 | |
2800d8d1 | 960 | /* mt-exec, de_thread() is waiting for us */ |
6db840fa | 961 | if (thread_group_leader(tsk) && |
2633f0e5 SV |
962 | tsk->signal->group_exit_task && |
963 | tsk->signal->notify_count < 0) | |
6db840fa ON |
964 | wake_up_process(tsk->signal->group_exit_task); |
965 | ||
1da177e4 LT |
966 | write_unlock_irq(&tasklist_lock); |
967 | ||
2b2a1ff6 RM |
968 | tracehook_report_death(tsk, signal, cookie, group_dead); |
969 | ||
1da177e4 | 970 | /* If the process is dead, release it - nobody will wait for it */ |
5c7edcd7 | 971 | if (signal == DEATH_REAP) |
1da177e4 | 972 | release_task(tsk); |
1da177e4 LT |
973 | } |
974 | ||
e18eecb8 JD |
975 | #ifdef CONFIG_DEBUG_STACK_USAGE |
976 | static void check_stack_usage(void) | |
977 | { | |
978 | static DEFINE_SPINLOCK(low_water_lock); | |
979 | static int lowest_to_date = THREAD_SIZE; | |
980 | unsigned long *n = end_of_stack(current); | |
981 | unsigned long free; | |
982 | ||
983 | while (*n == 0) | |
984 | n++; | |
985 | free = (unsigned long)n - (unsigned long)end_of_stack(current); | |
986 | ||
987 | if (free >= lowest_to_date) | |
988 | return; | |
989 | ||
990 | spin_lock(&low_water_lock); | |
991 | if (free < lowest_to_date) { | |
992 | printk(KERN_WARNING "%s used greatest stack depth: %lu bytes " | |
993 | "left\n", | |
994 | current->comm, free); | |
995 | lowest_to_date = free; | |
996 | } | |
997 | spin_unlock(&low_water_lock); | |
998 | } | |
999 | #else | |
1000 | static inline void check_stack_usage(void) {} | |
1001 | #endif | |
1002 | ||
7ad5b3a5 | 1003 | NORET_TYPE void do_exit(long code) |
1da177e4 LT |
1004 | { |
1005 | struct task_struct *tsk = current; | |
1006 | int group_dead; | |
1007 | ||
1008 | profile_task_exit(tsk); | |
1009 | ||
22e2c507 JA |
1010 | WARN_ON(atomic_read(&tsk->fs_excl)); |
1011 | ||
1da177e4 LT |
1012 | if (unlikely(in_interrupt())) |
1013 | panic("Aiee, killing interrupt handler!"); | |
1014 | if (unlikely(!tsk->pid)) | |
1015 | panic("Attempted to kill the idle task!"); | |
1da177e4 | 1016 | |
30199f5a | 1017 | tracehook_report_exit(&code); |
1da177e4 | 1018 | |
df164db5 AN |
1019 | /* |
1020 | * We're taking recursive faults here in do_exit. Safest is to just | |
1021 | * leave this task alone and wait for reboot. | |
1022 | */ | |
1023 | if (unlikely(tsk->flags & PF_EXITING)) { | |
1024 | printk(KERN_ALERT | |
1025 | "Fixing recursive fault but reboot is needed!\n"); | |
778e9a9c AK |
1026 | /* |
1027 | * We can do this unlocked here. The futex code uses | |
1028 | * this flag just to verify whether the pi state | |
1029 | * cleanup has been done or not. In the worst case it | |
1030 | * loops once more. We pretend that the cleanup was | |
1031 | * done as there is no way to return. Either the | |
1032 | * OWNER_DIED bit is set by now or we push the blocked | |
1033 | * task into the wait for ever nirwana as well. | |
1034 | */ | |
1035 | tsk->flags |= PF_EXITPIDONE; | |
df164db5 AN |
1036 | set_current_state(TASK_UNINTERRUPTIBLE); |
1037 | schedule(); | |
1038 | } | |
1039 | ||
d12619b5 | 1040 | exit_signals(tsk); /* sets PF_EXITING */ |
778e9a9c AK |
1041 | /* |
1042 | * tsk->flags are checked in the futex code to protect against | |
1043 | * an exiting task cleaning up the robust pi futexes. | |
1044 | */ | |
d2ee7198 ON |
1045 | smp_mb(); |
1046 | spin_unlock_wait(&tsk->pi_lock); | |
1da177e4 | 1047 | |
1da177e4 LT |
1048 | if (unlikely(in_atomic())) |
1049 | printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", | |
ba25f9dc | 1050 | current->comm, task_pid_nr(current), |
1da177e4 LT |
1051 | preempt_count()); |
1052 | ||
1053 | acct_update_integrals(tsk); | |
901608d9 | 1054 | |
1da177e4 | 1055 | group_dead = atomic_dec_and_test(&tsk->signal->live); |
c3068951 | 1056 | if (group_dead) { |
778e9a9c | 1057 | hrtimer_cancel(&tsk->signal->real_timer); |
25f407f0 | 1058 | exit_itimers(tsk->signal); |
c3068951 | 1059 | } |
f6ec29a4 | 1060 | acct_collect(code, group_dead); |
522ed776 MT |
1061 | if (group_dead) |
1062 | tty_audit_exit(); | |
fa84cb93 AV |
1063 | if (unlikely(tsk->audit_context)) |
1064 | audit_free(tsk); | |
115085ea | 1065 | |
f2ab6d88 | 1066 | tsk->exit_code = code; |
115085ea | 1067 | taskstats_exit(tsk, group_dead); |
c757249a | 1068 | |
1da177e4 LT |
1069 | exit_mm(tsk); |
1070 | ||
0e464814 | 1071 | if (group_dead) |
f6ec29a4 | 1072 | acct_process(); |
0a16b607 MD |
1073 | trace_sched_process_exit(tsk); |
1074 | ||
1da177e4 | 1075 | exit_sem(tsk); |
1ec7f1dd AV |
1076 | exit_files(tsk); |
1077 | exit_fs(tsk); | |
e18eecb8 | 1078 | check_stack_usage(); |
1da177e4 | 1079 | exit_thread(); |
b4f48b63 | 1080 | cgroup_exit(tsk, 1); |
1da177e4 LT |
1081 | |
1082 | if (group_dead && tsk->signal->leader) | |
1083 | disassociate_ctty(1); | |
1084 | ||
a1261f54 | 1085 | module_put(task_thread_info(tsk)->exec_domain->module); |
1da177e4 LT |
1086 | if (tsk->binfmt) |
1087 | module_put(tsk->binfmt->module); | |
1088 | ||
9f46080c | 1089 | proc_exit_connector(tsk); |
821c7de7 | 1090 | exit_notify(tsk, group_dead); |
1da177e4 | 1091 | #ifdef CONFIG_NUMA |
f0be3d32 | 1092 | mpol_put(tsk->mempolicy); |
1da177e4 LT |
1093 | tsk->mempolicy = NULL; |
1094 | #endif | |
42b2dd0a | 1095 | #ifdef CONFIG_FUTEX |
c87e2837 IM |
1096 | /* |
1097 | * This must happen late, after the PID is not | |
1098 | * hashed anymore: | |
1099 | */ | |
1100 | if (unlikely(!list_empty(&tsk->pi_state_list))) | |
1101 | exit_pi_state_list(tsk); | |
1102 | if (unlikely(current->pi_state_cache)) | |
1103 | kfree(current->pi_state_cache); | |
42b2dd0a | 1104 | #endif |
de5097c2 | 1105 | /* |
9a11b49a | 1106 | * Make sure we are holding no locks: |
de5097c2 | 1107 | */ |
9a11b49a | 1108 | debug_check_no_locks_held(tsk); |
778e9a9c AK |
1109 | /* |
1110 | * We can do this unlocked here. The futex code uses this flag | |
1111 | * just to verify whether the pi state cleanup has been done | |
1112 | * or not. In the worst case it loops once more. | |
1113 | */ | |
1114 | tsk->flags |= PF_EXITPIDONE; | |
1da177e4 | 1115 | |
afc847b7 AV |
1116 | if (tsk->io_context) |
1117 | exit_io_context(); | |
1118 | ||
b92ce558 JA |
1119 | if (tsk->splice_pipe) |
1120 | __free_pipe_info(tsk->splice_pipe); | |
1121 | ||
7407251a | 1122 | preempt_disable(); |
55a101f8 | 1123 | /* causes final put_task_struct in finish_task_switch(). */ |
c394cc9f | 1124 | tsk->state = TASK_DEAD; |
1da177e4 LT |
1125 | schedule(); |
1126 | BUG(); | |
1127 | /* Avoid "noreturn function does return". */ | |
54306cf0 AC |
1128 | for (;;) |
1129 | cpu_relax(); /* For when BUG is null */ | |
1da177e4 LT |
1130 | } |
1131 | ||
012914da RA |
1132 | EXPORT_SYMBOL_GPL(do_exit); |
1133 | ||
1da177e4 LT |
1134 | NORET_TYPE void complete_and_exit(struct completion *comp, long code) |
1135 | { | |
1136 | if (comp) | |
1137 | complete(comp); | |
55a101f8 | 1138 | |
1da177e4 LT |
1139 | do_exit(code); |
1140 | } | |
1141 | ||
1142 | EXPORT_SYMBOL(complete_and_exit); | |
1143 | ||
754fe8d2 | 1144 | SYSCALL_DEFINE1(exit, int, error_code) |
1da177e4 LT |
1145 | { |
1146 | do_exit((error_code&0xff)<<8); | |
1147 | } | |
1148 | ||
1da177e4 LT |
1149 | /* |
1150 | * Take down every thread in the group. This is called by fatal signals | |
1151 | * as well as by sys_exit_group (below). | |
1152 | */ | |
1153 | NORET_TYPE void | |
1154 | do_group_exit(int exit_code) | |
1155 | { | |
bfc4b089 ON |
1156 | struct signal_struct *sig = current->signal; |
1157 | ||
1da177e4 LT |
1158 | BUG_ON(exit_code & 0x80); /* core dumps don't get here */ |
1159 | ||
bfc4b089 ON |
1160 | if (signal_group_exit(sig)) |
1161 | exit_code = sig->group_exit_code; | |
1da177e4 | 1162 | else if (!thread_group_empty(current)) { |
1da177e4 | 1163 | struct sighand_struct *const sighand = current->sighand; |
1da177e4 | 1164 | spin_lock_irq(&sighand->siglock); |
ed5d2cac | 1165 | if (signal_group_exit(sig)) |
1da177e4 LT |
1166 | /* Another thread got here before we took the lock. */ |
1167 | exit_code = sig->group_exit_code; | |
1168 | else { | |
1da177e4 | 1169 | sig->group_exit_code = exit_code; |
ed5d2cac | 1170 | sig->flags = SIGNAL_GROUP_EXIT; |
1da177e4 LT |
1171 | zap_other_threads(current); |
1172 | } | |
1173 | spin_unlock_irq(&sighand->siglock); | |
1da177e4 LT |
1174 | } |
1175 | ||
1176 | do_exit(exit_code); | |
1177 | /* NOTREACHED */ | |
1178 | } | |
1179 | ||
1180 | /* | |
1181 | * this kills every thread in the thread group. Note that any externally | |
1182 | * wait4()-ing process will get the correct exit code - even if this | |
1183 | * thread is not the thread group leader. | |
1184 | */ | |
754fe8d2 | 1185 | SYSCALL_DEFINE1(exit_group, int, error_code) |
1da177e4 LT |
1186 | { |
1187 | do_group_exit((error_code & 0xff) << 8); | |
2ed7c03e HC |
1188 | /* NOTREACHED */ |
1189 | return 0; | |
1da177e4 LT |
1190 | } |
1191 | ||
161550d7 EB |
1192 | static struct pid *task_pid_type(struct task_struct *task, enum pid_type type) |
1193 | { | |
1194 | struct pid *pid = NULL; | |
1195 | if (type == PIDTYPE_PID) | |
1196 | pid = task->pids[type].pid; | |
1197 | else if (type < PIDTYPE_MAX) | |
1198 | pid = task->group_leader->pids[type].pid; | |
1199 | return pid; | |
1200 | } | |
1201 | ||
1202 | static int eligible_child(enum pid_type type, struct pid *pid, int options, | |
1203 | struct task_struct *p) | |
1da177e4 | 1204 | { |
73243284 RM |
1205 | int err; |
1206 | ||
161550d7 EB |
1207 | if (type < PIDTYPE_MAX) { |
1208 | if (task_pid_type(p, type) != pid) | |
1da177e4 LT |
1209 | return 0; |
1210 | } | |
1211 | ||
1da177e4 LT |
1212 | /* Wait for all children (clone and not) if __WALL is set; |
1213 | * otherwise, wait for clone children *only* if __WCLONE is | |
1214 | * set; otherwise, wait for non-clone children *only*. (Note: | |
1215 | * A "clone" child here is one that reports to its parent | |
1216 | * using a signal other than SIGCHLD.) */ | |
1217 | if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0)) | |
1218 | && !(options & __WALL)) | |
1219 | return 0; | |
1da177e4 | 1220 | |
73243284 | 1221 | err = security_task_wait(p); |
14dd0b81 RM |
1222 | if (err) |
1223 | return err; | |
1da177e4 | 1224 | |
14dd0b81 | 1225 | return 1; |
1da177e4 LT |
1226 | } |
1227 | ||
36c8b586 | 1228 | static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid, |
1da177e4 LT |
1229 | int why, int status, |
1230 | struct siginfo __user *infop, | |
1231 | struct rusage __user *rusagep) | |
1232 | { | |
1233 | int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0; | |
36c8b586 | 1234 | |
1da177e4 LT |
1235 | put_task_struct(p); |
1236 | if (!retval) | |
1237 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1238 | if (!retval) | |
1239 | retval = put_user(0, &infop->si_errno); | |
1240 | if (!retval) | |
1241 | retval = put_user((short)why, &infop->si_code); | |
1242 | if (!retval) | |
1243 | retval = put_user(pid, &infop->si_pid); | |
1244 | if (!retval) | |
1245 | retval = put_user(uid, &infop->si_uid); | |
1246 | if (!retval) | |
1247 | retval = put_user(status, &infop->si_status); | |
1248 | if (!retval) | |
1249 | retval = pid; | |
1250 | return retval; | |
1251 | } | |
1252 | ||
1253 | /* | |
1254 | * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold | |
1255 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1256 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1257 | * released the lock and the system call should return. | |
1258 | */ | |
98abed02 | 1259 | static int wait_task_zombie(struct task_struct *p, int options, |
1da177e4 LT |
1260 | struct siginfo __user *infop, |
1261 | int __user *stat_addr, struct rusage __user *ru) | |
1262 | { | |
1263 | unsigned long state; | |
2f4e6e2a | 1264 | int retval, status, traced; |
6c5f3e7b | 1265 | pid_t pid = task_pid_vnr(p); |
c69e8d9c | 1266 | uid_t uid = __task_cred(p)->uid; |
1da177e4 | 1267 | |
98abed02 RM |
1268 | if (!likely(options & WEXITED)) |
1269 | return 0; | |
1270 | ||
1271 | if (unlikely(options & WNOWAIT)) { | |
1da177e4 LT |
1272 | int exit_code = p->exit_code; |
1273 | int why, status; | |
1274 | ||
1da177e4 LT |
1275 | get_task_struct(p); |
1276 | read_unlock(&tasklist_lock); | |
1277 | if ((exit_code & 0x7f) == 0) { | |
1278 | why = CLD_EXITED; | |
1279 | status = exit_code >> 8; | |
1280 | } else { | |
1281 | why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED; | |
1282 | status = exit_code & 0x7f; | |
1283 | } | |
1284 | return wait_noreap_copyout(p, pid, uid, why, | |
1285 | status, infop, ru); | |
1286 | } | |
1287 | ||
1288 | /* | |
1289 | * Try to move the task's state to DEAD | |
1290 | * only one thread is allowed to do this: | |
1291 | */ | |
1292 | state = xchg(&p->exit_state, EXIT_DEAD); | |
1293 | if (state != EXIT_ZOMBIE) { | |
1294 | BUG_ON(state != EXIT_DEAD); | |
1295 | return 0; | |
1296 | } | |
1da177e4 | 1297 | |
53b6f9fb | 1298 | traced = ptrace_reparented(p); |
2f4e6e2a ON |
1299 | |
1300 | if (likely(!traced)) { | |
3795e161 JJ |
1301 | struct signal_struct *psig; |
1302 | struct signal_struct *sig; | |
f06febc9 | 1303 | struct task_cputime cputime; |
3795e161 | 1304 | |
1da177e4 LT |
1305 | /* |
1306 | * The resource counters for the group leader are in its | |
1307 | * own task_struct. Those for dead threads in the group | |
1308 | * are in its signal_struct, as are those for the child | |
1309 | * processes it has previously reaped. All these | |
1310 | * accumulate in the parent's signal_struct c* fields. | |
1311 | * | |
1312 | * We don't bother to take a lock here to protect these | |
1313 | * p->signal fields, because they are only touched by | |
1314 | * __exit_signal, which runs with tasklist_lock | |
1315 | * write-locked anyway, and so is excluded here. We do | |
1316 | * need to protect the access to p->parent->signal fields, | |
1317 | * as other threads in the parent group can be right | |
1318 | * here reaping other children at the same time. | |
f06febc9 FM |
1319 | * |
1320 | * We use thread_group_cputime() to get times for the thread | |
1321 | * group, which consolidates times for all threads in the | |
1322 | * group including the group leader. | |
1da177e4 | 1323 | */ |
2b5fe6de | 1324 | thread_group_cputime(p, &cputime); |
1da177e4 | 1325 | spin_lock_irq(&p->parent->sighand->siglock); |
3795e161 JJ |
1326 | psig = p->parent->signal; |
1327 | sig = p->signal; | |
1328 | psig->cutime = | |
1329 | cputime_add(psig->cutime, | |
f06febc9 FM |
1330 | cputime_add(cputime.utime, |
1331 | sig->cutime)); | |
3795e161 JJ |
1332 | psig->cstime = |
1333 | cputime_add(psig->cstime, | |
f06febc9 FM |
1334 | cputime_add(cputime.stime, |
1335 | sig->cstime)); | |
9ac52315 LV |
1336 | psig->cgtime = |
1337 | cputime_add(psig->cgtime, | |
1338 | cputime_add(p->gtime, | |
1339 | cputime_add(sig->gtime, | |
1340 | sig->cgtime))); | |
3795e161 JJ |
1341 | psig->cmin_flt += |
1342 | p->min_flt + sig->min_flt + sig->cmin_flt; | |
1343 | psig->cmaj_flt += | |
1344 | p->maj_flt + sig->maj_flt + sig->cmaj_flt; | |
1345 | psig->cnvcsw += | |
1346 | p->nvcsw + sig->nvcsw + sig->cnvcsw; | |
1347 | psig->cnivcsw += | |
1348 | p->nivcsw + sig->nivcsw + sig->cnivcsw; | |
6eaeeaba ED |
1349 | psig->cinblock += |
1350 | task_io_get_inblock(p) + | |
1351 | sig->inblock + sig->cinblock; | |
1352 | psig->coublock += | |
1353 | task_io_get_oublock(p) + | |
1354 | sig->oublock + sig->coublock; | |
5995477a AR |
1355 | task_io_accounting_add(&psig->ioac, &p->ioac); |
1356 | task_io_accounting_add(&psig->ioac, &sig->ioac); | |
1da177e4 LT |
1357 | spin_unlock_irq(&p->parent->sighand->siglock); |
1358 | } | |
1359 | ||
1360 | /* | |
1361 | * Now we are sure this task is interesting, and no other | |
1362 | * thread can reap it because we set its state to EXIT_DEAD. | |
1363 | */ | |
1364 | read_unlock(&tasklist_lock); | |
1365 | ||
1366 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; | |
1367 | status = (p->signal->flags & SIGNAL_GROUP_EXIT) | |
1368 | ? p->signal->group_exit_code : p->exit_code; | |
1369 | if (!retval && stat_addr) | |
1370 | retval = put_user(status, stat_addr); | |
1371 | if (!retval && infop) | |
1372 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1373 | if (!retval && infop) | |
1374 | retval = put_user(0, &infop->si_errno); | |
1375 | if (!retval && infop) { | |
1376 | int why; | |
1377 | ||
1378 | if ((status & 0x7f) == 0) { | |
1379 | why = CLD_EXITED; | |
1380 | status >>= 8; | |
1381 | } else { | |
1382 | why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED; | |
1383 | status &= 0x7f; | |
1384 | } | |
1385 | retval = put_user((short)why, &infop->si_code); | |
1386 | if (!retval) | |
1387 | retval = put_user(status, &infop->si_status); | |
1388 | } | |
1389 | if (!retval && infop) | |
3a515e4a | 1390 | retval = put_user(pid, &infop->si_pid); |
1da177e4 | 1391 | if (!retval && infop) |
c69e8d9c | 1392 | retval = put_user(uid, &infop->si_uid); |
2f4e6e2a | 1393 | if (!retval) |
3a515e4a | 1394 | retval = pid; |
2f4e6e2a ON |
1395 | |
1396 | if (traced) { | |
1da177e4 | 1397 | write_lock_irq(&tasklist_lock); |
2f4e6e2a ON |
1398 | /* We dropped tasklist, ptracer could die and untrace */ |
1399 | ptrace_unlink(p); | |
1400 | /* | |
1401 | * If this is not a detached task, notify the parent. | |
1402 | * If it's still not detached after that, don't release | |
1403 | * it now. | |
1404 | */ | |
d839fd4d | 1405 | if (!task_detached(p)) { |
2f4e6e2a | 1406 | do_notify_parent(p, p->exit_signal); |
d839fd4d | 1407 | if (!task_detached(p)) { |
2f4e6e2a ON |
1408 | p->exit_state = EXIT_ZOMBIE; |
1409 | p = NULL; | |
1da177e4 LT |
1410 | } |
1411 | } | |
1412 | write_unlock_irq(&tasklist_lock); | |
1413 | } | |
1414 | if (p != NULL) | |
1415 | release_task(p); | |
2f4e6e2a | 1416 | |
1da177e4 LT |
1417 | return retval; |
1418 | } | |
1419 | ||
1420 | /* | |
1421 | * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold | |
1422 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1423 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1424 | * released the lock and the system call should return. | |
1425 | */ | |
f470021a | 1426 | static int wait_task_stopped(int ptrace, struct task_struct *p, |
98abed02 | 1427 | int options, struct siginfo __user *infop, |
1da177e4 LT |
1428 | int __user *stat_addr, struct rusage __user *ru) |
1429 | { | |
ee7c82da ON |
1430 | int retval, exit_code, why; |
1431 | uid_t uid = 0; /* unneeded, required by compiler */ | |
c8950783 | 1432 | pid_t pid; |
1da177e4 | 1433 | |
f470021a | 1434 | if (!(options & WUNTRACED)) |
98abed02 RM |
1435 | return 0; |
1436 | ||
ee7c82da ON |
1437 | exit_code = 0; |
1438 | spin_lock_irq(&p->sighand->siglock); | |
1439 | ||
1440 | if (unlikely(!task_is_stopped_or_traced(p))) | |
1441 | goto unlock_sig; | |
1442 | ||
f470021a | 1443 | if (!ptrace && p->signal->group_stop_count > 0) |
1da177e4 LT |
1444 | /* |
1445 | * A group stop is in progress and this is the group leader. | |
1446 | * We won't report until all threads have stopped. | |
1447 | */ | |
ee7c82da ON |
1448 | goto unlock_sig; |
1449 | ||
1450 | exit_code = p->exit_code; | |
1451 | if (!exit_code) | |
1452 | goto unlock_sig; | |
1453 | ||
98abed02 | 1454 | if (!unlikely(options & WNOWAIT)) |
ee7c82da ON |
1455 | p->exit_code = 0; |
1456 | ||
c69e8d9c DH |
1457 | /* don't need the RCU readlock here as we're holding a spinlock */ |
1458 | uid = __task_cred(p)->uid; | |
ee7c82da ON |
1459 | unlock_sig: |
1460 | spin_unlock_irq(&p->sighand->siglock); | |
1461 | if (!exit_code) | |
1da177e4 LT |
1462 | return 0; |
1463 | ||
1464 | /* | |
1465 | * Now we are pretty sure this task is interesting. | |
1466 | * Make sure it doesn't get reaped out from under us while we | |
1467 | * give up the lock and then examine it below. We don't want to | |
1468 | * keep holding onto the tasklist_lock while we call getrusage and | |
1469 | * possibly take page faults for user memory. | |
1470 | */ | |
1471 | get_task_struct(p); | |
6c5f3e7b | 1472 | pid = task_pid_vnr(p); |
f470021a | 1473 | why = ptrace ? CLD_TRAPPED : CLD_STOPPED; |
1da177e4 LT |
1474 | read_unlock(&tasklist_lock); |
1475 | ||
98abed02 | 1476 | if (unlikely(options & WNOWAIT)) |
1da177e4 | 1477 | return wait_noreap_copyout(p, pid, uid, |
e6ceb32a | 1478 | why, exit_code, |
1da177e4 | 1479 | infop, ru); |
1da177e4 LT |
1480 | |
1481 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; | |
1482 | if (!retval && stat_addr) | |
1483 | retval = put_user((exit_code << 8) | 0x7f, stat_addr); | |
1484 | if (!retval && infop) | |
1485 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1486 | if (!retval && infop) | |
1487 | retval = put_user(0, &infop->si_errno); | |
1488 | if (!retval && infop) | |
6efcae46 | 1489 | retval = put_user((short)why, &infop->si_code); |
1da177e4 LT |
1490 | if (!retval && infop) |
1491 | retval = put_user(exit_code, &infop->si_status); | |
1492 | if (!retval && infop) | |
c8950783 | 1493 | retval = put_user(pid, &infop->si_pid); |
1da177e4 | 1494 | if (!retval && infop) |
ee7c82da | 1495 | retval = put_user(uid, &infop->si_uid); |
1da177e4 | 1496 | if (!retval) |
c8950783 | 1497 | retval = pid; |
1da177e4 LT |
1498 | put_task_struct(p); |
1499 | ||
1500 | BUG_ON(!retval); | |
1501 | return retval; | |
1502 | } | |
1503 | ||
1504 | /* | |
1505 | * Handle do_wait work for one task in a live, non-stopped state. | |
1506 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1507 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1508 | * released the lock and the system call should return. | |
1509 | */ | |
98abed02 | 1510 | static int wait_task_continued(struct task_struct *p, int options, |
1da177e4 LT |
1511 | struct siginfo __user *infop, |
1512 | int __user *stat_addr, struct rusage __user *ru) | |
1513 | { | |
1514 | int retval; | |
1515 | pid_t pid; | |
1516 | uid_t uid; | |
1517 | ||
98abed02 RM |
1518 | if (!unlikely(options & WCONTINUED)) |
1519 | return 0; | |
1520 | ||
1da177e4 LT |
1521 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) |
1522 | return 0; | |
1523 | ||
1524 | spin_lock_irq(&p->sighand->siglock); | |
1525 | /* Re-check with the lock held. */ | |
1526 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) { | |
1527 | spin_unlock_irq(&p->sighand->siglock); | |
1528 | return 0; | |
1529 | } | |
98abed02 | 1530 | if (!unlikely(options & WNOWAIT)) |
1da177e4 | 1531 | p->signal->flags &= ~SIGNAL_STOP_CONTINUED; |
c69e8d9c | 1532 | uid = __task_cred(p)->uid; |
1da177e4 LT |
1533 | spin_unlock_irq(&p->sighand->siglock); |
1534 | ||
6c5f3e7b | 1535 | pid = task_pid_vnr(p); |
1da177e4 LT |
1536 | get_task_struct(p); |
1537 | read_unlock(&tasklist_lock); | |
1538 | ||
1539 | if (!infop) { | |
1540 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; | |
1541 | put_task_struct(p); | |
1542 | if (!retval && stat_addr) | |
1543 | retval = put_user(0xffff, stat_addr); | |
1544 | if (!retval) | |
3a515e4a | 1545 | retval = pid; |
1da177e4 LT |
1546 | } else { |
1547 | retval = wait_noreap_copyout(p, pid, uid, | |
1548 | CLD_CONTINUED, SIGCONT, | |
1549 | infop, ru); | |
1550 | BUG_ON(retval == 0); | |
1551 | } | |
1552 | ||
1553 | return retval; | |
1554 | } | |
1555 | ||
98abed02 RM |
1556 | /* |
1557 | * Consider @p for a wait by @parent. | |
1558 | * | |
1559 | * -ECHILD should be in *@notask_error before the first call. | |
1560 | * Returns nonzero for a final return, when we have unlocked tasklist_lock. | |
1561 | * Returns zero if the search for a child should continue; | |
14dd0b81 RM |
1562 | * then *@notask_error is 0 if @p is an eligible child, |
1563 | * or another error from security_task_wait(), or still -ECHILD. | |
98abed02 | 1564 | */ |
f470021a | 1565 | static int wait_consider_task(struct task_struct *parent, int ptrace, |
98abed02 RM |
1566 | struct task_struct *p, int *notask_error, |
1567 | enum pid_type type, struct pid *pid, int options, | |
1568 | struct siginfo __user *infop, | |
1569 | int __user *stat_addr, struct rusage __user *ru) | |
1570 | { | |
1571 | int ret = eligible_child(type, pid, options, p); | |
14dd0b81 | 1572 | if (!ret) |
98abed02 RM |
1573 | return ret; |
1574 | ||
14dd0b81 RM |
1575 | if (unlikely(ret < 0)) { |
1576 | /* | |
1577 | * If we have not yet seen any eligible child, | |
1578 | * then let this error code replace -ECHILD. | |
1579 | * A permission error will give the user a clue | |
1580 | * to look for security policy problems, rather | |
1581 | * than for mysterious wait bugs. | |
1582 | */ | |
1583 | if (*notask_error) | |
1584 | *notask_error = ret; | |
1585 | } | |
1586 | ||
f470021a RM |
1587 | if (likely(!ptrace) && unlikely(p->ptrace)) { |
1588 | /* | |
1589 | * This child is hidden by ptrace. | |
1590 | * We aren't allowed to see it now, but eventually we will. | |
1591 | */ | |
1592 | *notask_error = 0; | |
1593 | return 0; | |
1594 | } | |
1595 | ||
98abed02 RM |
1596 | if (p->exit_state == EXIT_DEAD) |
1597 | return 0; | |
1598 | ||
1599 | /* | |
1600 | * We don't reap group leaders with subthreads. | |
1601 | */ | |
1602 | if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p)) | |
1603 | return wait_task_zombie(p, options, infop, stat_addr, ru); | |
1604 | ||
1605 | /* | |
1606 | * It's stopped or running now, so it might | |
1607 | * later continue, exit, or stop again. | |
1608 | */ | |
1609 | *notask_error = 0; | |
1610 | ||
1611 | if (task_is_stopped_or_traced(p)) | |
f470021a RM |
1612 | return wait_task_stopped(ptrace, p, options, |
1613 | infop, stat_addr, ru); | |
98abed02 RM |
1614 | |
1615 | return wait_task_continued(p, options, infop, stat_addr, ru); | |
1616 | } | |
1617 | ||
1618 | /* | |
1619 | * Do the work of do_wait() for one thread in the group, @tsk. | |
1620 | * | |
1621 | * -ECHILD should be in *@notask_error before the first call. | |
1622 | * Returns nonzero for a final return, when we have unlocked tasklist_lock. | |
1623 | * Returns zero if the search for a child should continue; then | |
14dd0b81 RM |
1624 | * *@notask_error is 0 if there were any eligible children, |
1625 | * or another error from security_task_wait(), or still -ECHILD. | |
98abed02 RM |
1626 | */ |
1627 | static int do_wait_thread(struct task_struct *tsk, int *notask_error, | |
1628 | enum pid_type type, struct pid *pid, int options, | |
1629 | struct siginfo __user *infop, int __user *stat_addr, | |
1630 | struct rusage __user *ru) | |
1631 | { | |
1632 | struct task_struct *p; | |
1633 | ||
1634 | list_for_each_entry(p, &tsk->children, sibling) { | |
f470021a RM |
1635 | /* |
1636 | * Do not consider detached threads. | |
1637 | */ | |
1638 | if (!task_detached(p)) { | |
1639 | int ret = wait_consider_task(tsk, 0, p, notask_error, | |
1640 | type, pid, options, | |
1641 | infop, stat_addr, ru); | |
1642 | if (ret) | |
1643 | return ret; | |
1644 | } | |
98abed02 RM |
1645 | } |
1646 | ||
1647 | return 0; | |
1648 | } | |
1649 | ||
1650 | static int ptrace_do_wait(struct task_struct *tsk, int *notask_error, | |
1651 | enum pid_type type, struct pid *pid, int options, | |
1652 | struct siginfo __user *infop, int __user *stat_addr, | |
1653 | struct rusage __user *ru) | |
1654 | { | |
1655 | struct task_struct *p; | |
1656 | ||
1657 | /* | |
f470021a | 1658 | * Traditionally we see ptrace'd stopped tasks regardless of options. |
98abed02 | 1659 | */ |
f470021a | 1660 | options |= WUNTRACED; |
98abed02 | 1661 | |
f470021a RM |
1662 | list_for_each_entry(p, &tsk->ptraced, ptrace_entry) { |
1663 | int ret = wait_consider_task(tsk, 1, p, notask_error, | |
1664 | type, pid, options, | |
1665 | infop, stat_addr, ru); | |
1666 | if (ret) | |
98abed02 | 1667 | return ret; |
98abed02 RM |
1668 | } |
1669 | ||
1670 | return 0; | |
1671 | } | |
1672 | ||
161550d7 EB |
1673 | static long do_wait(enum pid_type type, struct pid *pid, int options, |
1674 | struct siginfo __user *infop, int __user *stat_addr, | |
1675 | struct rusage __user *ru) | |
1da177e4 LT |
1676 | { |
1677 | DECLARE_WAITQUEUE(wait, current); | |
1678 | struct task_struct *tsk; | |
98abed02 | 1679 | int retval; |
1da177e4 | 1680 | |
0a16b607 MD |
1681 | trace_sched_process_wait(pid); |
1682 | ||
1da177e4 LT |
1683 | add_wait_queue(¤t->signal->wait_chldexit,&wait); |
1684 | repeat: | |
98abed02 RM |
1685 | /* |
1686 | * If there is nothing that can match our critiera just get out. | |
1687 | * We will clear @retval to zero if we see any child that might later | |
1688 | * match our criteria, even if we are not able to reap it yet. | |
1689 | */ | |
161550d7 EB |
1690 | retval = -ECHILD; |
1691 | if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type]))) | |
1692 | goto end; | |
1693 | ||
1da177e4 LT |
1694 | current->state = TASK_INTERRUPTIBLE; |
1695 | read_lock(&tasklist_lock); | |
1696 | tsk = current; | |
1697 | do { | |
98abed02 RM |
1698 | int tsk_result = do_wait_thread(tsk, &retval, |
1699 | type, pid, options, | |
1700 | infop, stat_addr, ru); | |
1701 | if (!tsk_result) | |
1702 | tsk_result = ptrace_do_wait(tsk, &retval, | |
1703 | type, pid, options, | |
1704 | infop, stat_addr, ru); | |
1705 | if (tsk_result) { | |
1706 | /* | |
1707 | * tasklist_lock is unlocked and we have a final result. | |
1708 | */ | |
1709 | retval = tsk_result; | |
1710 | goto end; | |
1da177e4 | 1711 | } |
98abed02 | 1712 | |
1da177e4 LT |
1713 | if (options & __WNOTHREAD) |
1714 | break; | |
1715 | tsk = next_thread(tsk); | |
125e1874 | 1716 | BUG_ON(tsk->signal != current->signal); |
1da177e4 | 1717 | } while (tsk != current); |
1da177e4 | 1718 | read_unlock(&tasklist_lock); |
f2cc3eb1 | 1719 | |
98abed02 | 1720 | if (!retval && !(options & WNOHANG)) { |
1da177e4 | 1721 | retval = -ERESTARTSYS; |
98abed02 RM |
1722 | if (!signal_pending(current)) { |
1723 | schedule(); | |
1724 | goto repeat; | |
1725 | } | |
1da177e4 | 1726 | } |
98abed02 | 1727 | |
1da177e4 LT |
1728 | end: |
1729 | current->state = TASK_RUNNING; | |
1730 | remove_wait_queue(¤t->signal->wait_chldexit,&wait); | |
1731 | if (infop) { | |
1732 | if (retval > 0) | |
9cbab810 | 1733 | retval = 0; |
1da177e4 LT |
1734 | else { |
1735 | /* | |
1736 | * For a WNOHANG return, clear out all the fields | |
1737 | * we would set so the user can easily tell the | |
1738 | * difference. | |
1739 | */ | |
1740 | if (!retval) | |
1741 | retval = put_user(0, &infop->si_signo); | |
1742 | if (!retval) | |
1743 | retval = put_user(0, &infop->si_errno); | |
1744 | if (!retval) | |
1745 | retval = put_user(0, &infop->si_code); | |
1746 | if (!retval) | |
1747 | retval = put_user(0, &infop->si_pid); | |
1748 | if (!retval) | |
1749 | retval = put_user(0, &infop->si_uid); | |
1750 | if (!retval) | |
1751 | retval = put_user(0, &infop->si_status); | |
1752 | } | |
1753 | } | |
1754 | return retval; | |
1755 | } | |
1756 | ||
17da2bd9 HC |
1757 | SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, |
1758 | infop, int, options, struct rusage __user *, ru) | |
1da177e4 | 1759 | { |
161550d7 EB |
1760 | struct pid *pid = NULL; |
1761 | enum pid_type type; | |
1da177e4 LT |
1762 | long ret; |
1763 | ||
1764 | if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED)) | |
1765 | return -EINVAL; | |
1766 | if (!(options & (WEXITED|WSTOPPED|WCONTINUED))) | |
1767 | return -EINVAL; | |
1768 | ||
1769 | switch (which) { | |
1770 | case P_ALL: | |
161550d7 | 1771 | type = PIDTYPE_MAX; |
1da177e4 LT |
1772 | break; |
1773 | case P_PID: | |
161550d7 EB |
1774 | type = PIDTYPE_PID; |
1775 | if (upid <= 0) | |
1da177e4 LT |
1776 | return -EINVAL; |
1777 | break; | |
1778 | case P_PGID: | |
161550d7 EB |
1779 | type = PIDTYPE_PGID; |
1780 | if (upid <= 0) | |
1da177e4 | 1781 | return -EINVAL; |
1da177e4 LT |
1782 | break; |
1783 | default: | |
1784 | return -EINVAL; | |
1785 | } | |
1786 | ||
161550d7 EB |
1787 | if (type < PIDTYPE_MAX) |
1788 | pid = find_get_pid(upid); | |
1789 | ret = do_wait(type, pid, options, infop, NULL, ru); | |
1790 | put_pid(pid); | |
1da177e4 LT |
1791 | |
1792 | /* avoid REGPARM breakage on x86: */ | |
54a01510 | 1793 | asmlinkage_protect(5, ret, which, upid, infop, options, ru); |
1da177e4 LT |
1794 | return ret; |
1795 | } | |
1796 | ||
754fe8d2 HC |
1797 | SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr, |
1798 | int, options, struct rusage __user *, ru) | |
1da177e4 | 1799 | { |
161550d7 EB |
1800 | struct pid *pid = NULL; |
1801 | enum pid_type type; | |
1da177e4 LT |
1802 | long ret; |
1803 | ||
1804 | if (options & ~(WNOHANG|WUNTRACED|WCONTINUED| | |
1805 | __WNOTHREAD|__WCLONE|__WALL)) | |
1806 | return -EINVAL; | |
161550d7 EB |
1807 | |
1808 | if (upid == -1) | |
1809 | type = PIDTYPE_MAX; | |
1810 | else if (upid < 0) { | |
1811 | type = PIDTYPE_PGID; | |
1812 | pid = find_get_pid(-upid); | |
1813 | } else if (upid == 0) { | |
1814 | type = PIDTYPE_PGID; | |
1815 | pid = get_pid(task_pgrp(current)); | |
1816 | } else /* upid > 0 */ { | |
1817 | type = PIDTYPE_PID; | |
1818 | pid = find_get_pid(upid); | |
1819 | } | |
1820 | ||
1821 | ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru); | |
1822 | put_pid(pid); | |
1da177e4 LT |
1823 | |
1824 | /* avoid REGPARM breakage on x86: */ | |
54a01510 | 1825 | asmlinkage_protect(4, ret, upid, stat_addr, options, ru); |
1da177e4 LT |
1826 | return ret; |
1827 | } | |
1828 | ||
1829 | #ifdef __ARCH_WANT_SYS_WAITPID | |
1830 | ||
1831 | /* | |
1832 | * sys_waitpid() remains for compatibility. waitpid() should be | |
1833 | * implemented by calling sys_wait4() from libc.a. | |
1834 | */ | |
17da2bd9 | 1835 | SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options) |
1da177e4 LT |
1836 | { |
1837 | return sys_wait4(pid, stat_addr, options, NULL); | |
1838 | } | |
1839 | ||
1840 | #endif |