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1 | /* | |
2 | * linux/kernel/exit.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | #include <linux/mm.h> | |
8 | #include <linux/slab.h> | |
9 | #include <linux/interrupt.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/capability.h> | |
12 | #include <linux/completion.h> | |
13 | #include <linux/personality.h> | |
14 | #include <linux/tty.h> | |
15 | #include <linux/mnt_namespace.h> | |
16 | #include <linux/key.h> | |
17 | #include <linux/security.h> | |
18 | #include <linux/cpu.h> | |
19 | #include <linux/acct.h> | |
20 | #include <linux/tsacct_kern.h> | |
21 | #include <linux/file.h> | |
22 | #include <linux/binfmts.h> | |
23 | #include <linux/nsproxy.h> | |
24 | #include <linux/pid_namespace.h> | |
25 | #include <linux/ptrace.h> | |
26 | #include <linux/profile.h> | |
27 | #include <linux/mount.h> | |
28 | #include <linux/proc_fs.h> | |
29 | #include <linux/kthread.h> | |
30 | #include <linux/mempolicy.h> | |
31 | #include <linux/taskstats_kern.h> | |
32 | #include <linux/delayacct.h> | |
33 | #include <linux/freezer.h> | |
34 | #include <linux/cgroup.h> | |
35 | #include <linux/syscalls.h> | |
36 | #include <linux/signal.h> | |
37 | #include <linux/posix-timers.h> | |
38 | #include <linux/cn_proc.h> | |
39 | #include <linux/mutex.h> | |
40 | #include <linux/futex.h> | |
41 | #include <linux/compat.h> | |
42 | #include <linux/pipe_fs_i.h> | |
43 | #include <linux/audit.h> /* for audit_free() */ | |
44 | #include <linux/resource.h> | |
45 | #include <linux/blkdev.h> | |
46 | #include <linux/task_io_accounting_ops.h> | |
47 | ||
48 | #include <asm/uaccess.h> | |
49 | #include <asm/unistd.h> | |
50 | #include <asm/pgtable.h> | |
51 | #include <asm/mmu_context.h> | |
52 | ||
53 | static void exit_mm(struct task_struct * tsk); | |
54 | ||
55 | static void __unhash_process(struct task_struct *p) | |
56 | { | |
57 | nr_threads--; | |
58 | detach_pid(p, PIDTYPE_PID); | |
59 | if (thread_group_leader(p)) { | |
60 | detach_pid(p, PIDTYPE_PGID); | |
61 | detach_pid(p, PIDTYPE_SID); | |
62 | ||
63 | list_del_rcu(&p->tasks); | |
64 | __get_cpu_var(process_counts)--; | |
65 | } | |
66 | list_del_rcu(&p->thread_group); | |
67 | remove_parent(p); | |
68 | } | |
69 | ||
70 | /* | |
71 | * This function expects the tasklist_lock write-locked. | |
72 | */ | |
73 | static void __exit_signal(struct task_struct *tsk) | |
74 | { | |
75 | struct signal_struct *sig = tsk->signal; | |
76 | struct sighand_struct *sighand; | |
77 | ||
78 | BUG_ON(!sig); | |
79 | BUG_ON(!atomic_read(&sig->count)); | |
80 | ||
81 | rcu_read_lock(); | |
82 | sighand = rcu_dereference(tsk->sighand); | |
83 | spin_lock(&sighand->siglock); | |
84 | ||
85 | posix_cpu_timers_exit(tsk); | |
86 | if (atomic_dec_and_test(&sig->count)) | |
87 | posix_cpu_timers_exit_group(tsk); | |
88 | else { | |
89 | /* | |
90 | * If there is any task waiting for the group exit | |
91 | * then notify it: | |
92 | */ | |
93 | if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) | |
94 | wake_up_process(sig->group_exit_task); | |
95 | ||
96 | if (tsk == sig->curr_target) | |
97 | sig->curr_target = next_thread(tsk); | |
98 | /* | |
99 | * Accumulate here the counters for all threads but the | |
100 | * group leader as they die, so they can be added into | |
101 | * the process-wide totals when those are taken. | |
102 | * The group leader stays around as a zombie as long | |
103 | * as there are other threads. When it gets reaped, | |
104 | * the exit.c code will add its counts into these totals. | |
105 | * We won't ever get here for the group leader, since it | |
106 | * will have been the last reference on the signal_struct. | |
107 | */ | |
108 | sig->utime = cputime_add(sig->utime, tsk->utime); | |
109 | sig->stime = cputime_add(sig->stime, tsk->stime); | |
110 | sig->gtime = cputime_add(sig->gtime, tsk->gtime); | |
111 | sig->min_flt += tsk->min_flt; | |
112 | sig->maj_flt += tsk->maj_flt; | |
113 | sig->nvcsw += tsk->nvcsw; | |
114 | sig->nivcsw += tsk->nivcsw; | |
115 | sig->inblock += task_io_get_inblock(tsk); | |
116 | sig->oublock += task_io_get_oublock(tsk); | |
117 | sig->sum_sched_runtime += tsk->se.sum_exec_runtime; | |
118 | sig = NULL; /* Marker for below. */ | |
119 | } | |
120 | ||
121 | __unhash_process(tsk); | |
122 | ||
123 | tsk->signal = NULL; | |
124 | tsk->sighand = NULL; | |
125 | spin_unlock(&sighand->siglock); | |
126 | rcu_read_unlock(); | |
127 | ||
128 | __cleanup_sighand(sighand); | |
129 | clear_tsk_thread_flag(tsk,TIF_SIGPENDING); | |
130 | flush_sigqueue(&tsk->pending); | |
131 | if (sig) { | |
132 | flush_sigqueue(&sig->shared_pending); | |
133 | taskstats_tgid_free(sig); | |
134 | __cleanup_signal(sig); | |
135 | } | |
136 | } | |
137 | ||
138 | static void delayed_put_task_struct(struct rcu_head *rhp) | |
139 | { | |
140 | put_task_struct(container_of(rhp, struct task_struct, rcu)); | |
141 | } | |
142 | ||
143 | void release_task(struct task_struct * p) | |
144 | { | |
145 | struct task_struct *leader; | |
146 | int zap_leader; | |
147 | repeat: | |
148 | atomic_dec(&p->user->processes); | |
149 | proc_flush_task(p); | |
150 | write_lock_irq(&tasklist_lock); | |
151 | ptrace_unlink(p); | |
152 | BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children)); | |
153 | __exit_signal(p); | |
154 | ||
155 | /* | |
156 | * If we are the last non-leader member of the thread | |
157 | * group, and the leader is zombie, then notify the | |
158 | * group leader's parent process. (if it wants notification.) | |
159 | */ | |
160 | zap_leader = 0; | |
161 | leader = p->group_leader; | |
162 | if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) { | |
163 | BUG_ON(leader->exit_signal == -1); | |
164 | do_notify_parent(leader, leader->exit_signal); | |
165 | /* | |
166 | * If we were the last child thread and the leader has | |
167 | * exited already, and the leader's parent ignores SIGCHLD, | |
168 | * then we are the one who should release the leader. | |
169 | * | |
170 | * do_notify_parent() will have marked it self-reaping in | |
171 | * that case. | |
172 | */ | |
173 | zap_leader = (leader->exit_signal == -1); | |
174 | } | |
175 | ||
176 | write_unlock_irq(&tasklist_lock); | |
177 | release_thread(p); | |
178 | call_rcu(&p->rcu, delayed_put_task_struct); | |
179 | ||
180 | p = leader; | |
181 | if (unlikely(zap_leader)) | |
182 | goto repeat; | |
183 | } | |
184 | ||
185 | /* | |
186 | * This checks not only the pgrp, but falls back on the pid if no | |
187 | * satisfactory pgrp is found. I dunno - gdb doesn't work correctly | |
188 | * without this... | |
189 | * | |
190 | * The caller must hold rcu lock or the tasklist lock. | |
191 | */ | |
192 | struct pid *session_of_pgrp(struct pid *pgrp) | |
193 | { | |
194 | struct task_struct *p; | |
195 | struct pid *sid = NULL; | |
196 | ||
197 | p = pid_task(pgrp, PIDTYPE_PGID); | |
198 | if (p == NULL) | |
199 | p = pid_task(pgrp, PIDTYPE_PID); | |
200 | if (p != NULL) | |
201 | sid = task_session(p); | |
202 | ||
203 | return sid; | |
204 | } | |
205 | ||
206 | /* | |
207 | * Determine if a process group is "orphaned", according to the POSIX | |
208 | * definition in 2.2.2.52. Orphaned process groups are not to be affected | |
209 | * by terminal-generated stop signals. Newly orphaned process groups are | |
210 | * to receive a SIGHUP and a SIGCONT. | |
211 | * | |
212 | * "I ask you, have you ever known what it is to be an orphan?" | |
213 | */ | |
214 | static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task) | |
215 | { | |
216 | struct task_struct *p; | |
217 | ||
218 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { | |
219 | if ((p == ignored_task) || | |
220 | (p->exit_state && thread_group_empty(p)) || | |
221 | is_global_init(p->real_parent)) | |
222 | continue; | |
223 | ||
224 | if (task_pgrp(p->real_parent) != pgrp && | |
225 | task_session(p->real_parent) == task_session(p)) | |
226 | return 0; | |
227 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); | |
228 | ||
229 | return 1; | |
230 | } | |
231 | ||
232 | int is_current_pgrp_orphaned(void) | |
233 | { | |
234 | int retval; | |
235 | ||
236 | read_lock(&tasklist_lock); | |
237 | retval = will_become_orphaned_pgrp(task_pgrp(current), NULL); | |
238 | read_unlock(&tasklist_lock); | |
239 | ||
240 | return retval; | |
241 | } | |
242 | ||
243 | static int has_stopped_jobs(struct pid *pgrp) | |
244 | { | |
245 | int retval = 0; | |
246 | struct task_struct *p; | |
247 | ||
248 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { | |
249 | if (!task_is_stopped(p)) | |
250 | continue; | |
251 | retval = 1; | |
252 | break; | |
253 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); | |
254 | return retval; | |
255 | } | |
256 | ||
257 | /* | |
258 | * Check to see if any process groups have become orphaned as | |
259 | * a result of our exiting, and if they have any stopped jobs, | |
260 | * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) | |
261 | */ | |
262 | static void | |
263 | kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) | |
264 | { | |
265 | struct pid *pgrp = task_pgrp(tsk); | |
266 | struct task_struct *ignored_task = tsk; | |
267 | ||
268 | if (!parent) | |
269 | /* exit: our father is in a different pgrp than | |
270 | * we are and we were the only connection outside. | |
271 | */ | |
272 | parent = tsk->real_parent; | |
273 | else | |
274 | /* reparent: our child is in a different pgrp than | |
275 | * we are, and it was the only connection outside. | |
276 | */ | |
277 | ignored_task = NULL; | |
278 | ||
279 | if (task_pgrp(parent) != pgrp && | |
280 | task_session(parent) == task_session(tsk) && | |
281 | will_become_orphaned_pgrp(pgrp, ignored_task) && | |
282 | has_stopped_jobs(pgrp)) { | |
283 | __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp); | |
284 | __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp); | |
285 | } | |
286 | } | |
287 | ||
288 | /** | |
289 | * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd | |
290 | * | |
291 | * If a kernel thread is launched as a result of a system call, or if | |
292 | * it ever exits, it should generally reparent itself to kthreadd so it | |
293 | * isn't in the way of other processes and is correctly cleaned up on exit. | |
294 | * | |
295 | * The various task state such as scheduling policy and priority may have | |
296 | * been inherited from a user process, so we reset them to sane values here. | |
297 | * | |
298 | * NOTE that reparent_to_kthreadd() gives the caller full capabilities. | |
299 | */ | |
300 | static void reparent_to_kthreadd(void) | |
301 | { | |
302 | write_lock_irq(&tasklist_lock); | |
303 | ||
304 | ptrace_unlink(current); | |
305 | /* Reparent to init */ | |
306 | remove_parent(current); | |
307 | current->real_parent = current->parent = kthreadd_task; | |
308 | add_parent(current); | |
309 | ||
310 | /* Set the exit signal to SIGCHLD so we signal init on exit */ | |
311 | current->exit_signal = SIGCHLD; | |
312 | ||
313 | if (task_nice(current) < 0) | |
314 | set_user_nice(current, 0); | |
315 | /* cpus_allowed? */ | |
316 | /* rt_priority? */ | |
317 | /* signals? */ | |
318 | security_task_reparent_to_init(current); | |
319 | memcpy(current->signal->rlim, init_task.signal->rlim, | |
320 | sizeof(current->signal->rlim)); | |
321 | atomic_inc(&(INIT_USER->__count)); | |
322 | write_unlock_irq(&tasklist_lock); | |
323 | switch_uid(INIT_USER); | |
324 | } | |
325 | ||
326 | void __set_special_pids(struct pid *pid) | |
327 | { | |
328 | struct task_struct *curr = current->group_leader; | |
329 | pid_t nr = pid_nr(pid); | |
330 | ||
331 | if (task_session(curr) != pid) { | |
332 | detach_pid(curr, PIDTYPE_SID); | |
333 | attach_pid(curr, PIDTYPE_SID, pid); | |
334 | set_task_session(curr, nr); | |
335 | } | |
336 | if (task_pgrp(curr) != pid) { | |
337 | detach_pid(curr, PIDTYPE_PGID); | |
338 | attach_pid(curr, PIDTYPE_PGID, pid); | |
339 | set_task_pgrp(curr, nr); | |
340 | } | |
341 | } | |
342 | ||
343 | static void set_special_pids(struct pid *pid) | |
344 | { | |
345 | write_lock_irq(&tasklist_lock); | |
346 | __set_special_pids(pid); | |
347 | write_unlock_irq(&tasklist_lock); | |
348 | } | |
349 | ||
350 | /* | |
351 | * Let kernel threads use this to say that they | |
352 | * allow a certain signal (since daemonize() will | |
353 | * have disabled all of them by default). | |
354 | */ | |
355 | int allow_signal(int sig) | |
356 | { | |
357 | if (!valid_signal(sig) || sig < 1) | |
358 | return -EINVAL; | |
359 | ||
360 | spin_lock_irq(¤t->sighand->siglock); | |
361 | sigdelset(¤t->blocked, sig); | |
362 | if (!current->mm) { | |
363 | /* Kernel threads handle their own signals. | |
364 | Let the signal code know it'll be handled, so | |
365 | that they don't get converted to SIGKILL or | |
366 | just silently dropped */ | |
367 | current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; | |
368 | } | |
369 | recalc_sigpending(); | |
370 | spin_unlock_irq(¤t->sighand->siglock); | |
371 | return 0; | |
372 | } | |
373 | ||
374 | EXPORT_SYMBOL(allow_signal); | |
375 | ||
376 | int disallow_signal(int sig) | |
377 | { | |
378 | if (!valid_signal(sig) || sig < 1) | |
379 | return -EINVAL; | |
380 | ||
381 | spin_lock_irq(¤t->sighand->siglock); | |
382 | current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; | |
383 | recalc_sigpending(); | |
384 | spin_unlock_irq(¤t->sighand->siglock); | |
385 | return 0; | |
386 | } | |
387 | ||
388 | EXPORT_SYMBOL(disallow_signal); | |
389 | ||
390 | /* | |
391 | * Put all the gunge required to become a kernel thread without | |
392 | * attached user resources in one place where it belongs. | |
393 | */ | |
394 | ||
395 | void daemonize(const char *name, ...) | |
396 | { | |
397 | va_list args; | |
398 | struct fs_struct *fs; | |
399 | sigset_t blocked; | |
400 | ||
401 | va_start(args, name); | |
402 | vsnprintf(current->comm, sizeof(current->comm), name, args); | |
403 | va_end(args); | |
404 | ||
405 | /* | |
406 | * If we were started as result of loading a module, close all of the | |
407 | * user space pages. We don't need them, and if we didn't close them | |
408 | * they would be locked into memory. | |
409 | */ | |
410 | exit_mm(current); | |
411 | /* | |
412 | * We don't want to have TIF_FREEZE set if the system-wide hibernation | |
413 | * or suspend transition begins right now. | |
414 | */ | |
415 | current->flags |= PF_NOFREEZE; | |
416 | ||
417 | if (current->nsproxy != &init_nsproxy) { | |
418 | get_nsproxy(&init_nsproxy); | |
419 | switch_task_namespaces(current, &init_nsproxy); | |
420 | } | |
421 | set_special_pids(&init_struct_pid); | |
422 | proc_clear_tty(current); | |
423 | ||
424 | /* Block and flush all signals */ | |
425 | sigfillset(&blocked); | |
426 | sigprocmask(SIG_BLOCK, &blocked, NULL); | |
427 | flush_signals(current); | |
428 | ||
429 | /* Become as one with the init task */ | |
430 | ||
431 | exit_fs(current); /* current->fs->count--; */ | |
432 | fs = init_task.fs; | |
433 | current->fs = fs; | |
434 | atomic_inc(&fs->count); | |
435 | ||
436 | exit_files(current); | |
437 | current->files = init_task.files; | |
438 | atomic_inc(¤t->files->count); | |
439 | ||
440 | reparent_to_kthreadd(); | |
441 | } | |
442 | ||
443 | EXPORT_SYMBOL(daemonize); | |
444 | ||
445 | static void close_files(struct files_struct * files) | |
446 | { | |
447 | int i, j; | |
448 | struct fdtable *fdt; | |
449 | ||
450 | j = 0; | |
451 | ||
452 | /* | |
453 | * It is safe to dereference the fd table without RCU or | |
454 | * ->file_lock because this is the last reference to the | |
455 | * files structure. | |
456 | */ | |
457 | fdt = files_fdtable(files); | |
458 | for (;;) { | |
459 | unsigned long set; | |
460 | i = j * __NFDBITS; | |
461 | if (i >= fdt->max_fds) | |
462 | break; | |
463 | set = fdt->open_fds->fds_bits[j++]; | |
464 | while (set) { | |
465 | if (set & 1) { | |
466 | struct file * file = xchg(&fdt->fd[i], NULL); | |
467 | if (file) { | |
468 | filp_close(file, files); | |
469 | cond_resched(); | |
470 | } | |
471 | } | |
472 | i++; | |
473 | set >>= 1; | |
474 | } | |
475 | } | |
476 | } | |
477 | ||
478 | struct files_struct *get_files_struct(struct task_struct *task) | |
479 | { | |
480 | struct files_struct *files; | |
481 | ||
482 | task_lock(task); | |
483 | files = task->files; | |
484 | if (files) | |
485 | atomic_inc(&files->count); | |
486 | task_unlock(task); | |
487 | ||
488 | return files; | |
489 | } | |
490 | ||
491 | void put_files_struct(struct files_struct *files) | |
492 | { | |
493 | struct fdtable *fdt; | |
494 | ||
495 | if (atomic_dec_and_test(&files->count)) { | |
496 | close_files(files); | |
497 | /* | |
498 | * Free the fd and fdset arrays if we expanded them. | |
499 | * If the fdtable was embedded, pass files for freeing | |
500 | * at the end of the RCU grace period. Otherwise, | |
501 | * you can free files immediately. | |
502 | */ | |
503 | fdt = files_fdtable(files); | |
504 | if (fdt != &files->fdtab) | |
505 | kmem_cache_free(files_cachep, files); | |
506 | free_fdtable(fdt); | |
507 | } | |
508 | } | |
509 | ||
510 | EXPORT_SYMBOL(put_files_struct); | |
511 | ||
512 | void reset_files_struct(struct task_struct *tsk, struct files_struct *files) | |
513 | { | |
514 | struct files_struct *old; | |
515 | ||
516 | old = tsk->files; | |
517 | task_lock(tsk); | |
518 | tsk->files = files; | |
519 | task_unlock(tsk); | |
520 | put_files_struct(old); | |
521 | } | |
522 | EXPORT_SYMBOL(reset_files_struct); | |
523 | ||
524 | static void __exit_files(struct task_struct *tsk) | |
525 | { | |
526 | struct files_struct * files = tsk->files; | |
527 | ||
528 | if (files) { | |
529 | task_lock(tsk); | |
530 | tsk->files = NULL; | |
531 | task_unlock(tsk); | |
532 | put_files_struct(files); | |
533 | } | |
534 | } | |
535 | ||
536 | void exit_files(struct task_struct *tsk) | |
537 | { | |
538 | __exit_files(tsk); | |
539 | } | |
540 | ||
541 | static void __put_fs_struct(struct fs_struct *fs) | |
542 | { | |
543 | /* No need to hold fs->lock if we are killing it */ | |
544 | if (atomic_dec_and_test(&fs->count)) { | |
545 | path_put(&fs->root); | |
546 | path_put(&fs->pwd); | |
547 | if (fs->altroot.dentry) | |
548 | path_put(&fs->altroot); | |
549 | kmem_cache_free(fs_cachep, fs); | |
550 | } | |
551 | } | |
552 | ||
553 | void put_fs_struct(struct fs_struct *fs) | |
554 | { | |
555 | __put_fs_struct(fs); | |
556 | } | |
557 | ||
558 | static void __exit_fs(struct task_struct *tsk) | |
559 | { | |
560 | struct fs_struct * fs = tsk->fs; | |
561 | ||
562 | if (fs) { | |
563 | task_lock(tsk); | |
564 | tsk->fs = NULL; | |
565 | task_unlock(tsk); | |
566 | __put_fs_struct(fs); | |
567 | } | |
568 | } | |
569 | ||
570 | void exit_fs(struct task_struct *tsk) | |
571 | { | |
572 | __exit_fs(tsk); | |
573 | } | |
574 | ||
575 | EXPORT_SYMBOL_GPL(exit_fs); | |
576 | ||
577 | /* | |
578 | * Turn us into a lazy TLB process if we | |
579 | * aren't already.. | |
580 | */ | |
581 | static void exit_mm(struct task_struct * tsk) | |
582 | { | |
583 | struct mm_struct *mm = tsk->mm; | |
584 | ||
585 | mm_release(tsk, mm); | |
586 | if (!mm) | |
587 | return; | |
588 | /* | |
589 | * Serialize with any possible pending coredump. | |
590 | * We must hold mmap_sem around checking core_waiters | |
591 | * and clearing tsk->mm. The core-inducing thread | |
592 | * will increment core_waiters for each thread in the | |
593 | * group with ->mm != NULL. | |
594 | */ | |
595 | down_read(&mm->mmap_sem); | |
596 | if (mm->core_waiters) { | |
597 | up_read(&mm->mmap_sem); | |
598 | down_write(&mm->mmap_sem); | |
599 | if (!--mm->core_waiters) | |
600 | complete(mm->core_startup_done); | |
601 | up_write(&mm->mmap_sem); | |
602 | ||
603 | wait_for_completion(&mm->core_done); | |
604 | down_read(&mm->mmap_sem); | |
605 | } | |
606 | atomic_inc(&mm->mm_count); | |
607 | BUG_ON(mm != tsk->active_mm); | |
608 | /* more a memory barrier than a real lock */ | |
609 | task_lock(tsk); | |
610 | tsk->mm = NULL; | |
611 | up_read(&mm->mmap_sem); | |
612 | enter_lazy_tlb(mm, current); | |
613 | /* We don't want this task to be frozen prematurely */ | |
614 | clear_freeze_flag(tsk); | |
615 | task_unlock(tsk); | |
616 | mmput(mm); | |
617 | } | |
618 | ||
619 | static void | |
620 | reparent_thread(struct task_struct *p, struct task_struct *father, int traced) | |
621 | { | |
622 | if (p->pdeath_signal) | |
623 | /* We already hold the tasklist_lock here. */ | |
624 | group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p); | |
625 | ||
626 | /* Move the child from its dying parent to the new one. */ | |
627 | if (unlikely(traced)) { | |
628 | /* Preserve ptrace links if someone else is tracing this child. */ | |
629 | list_del_init(&p->ptrace_list); | |
630 | if (p->parent != p->real_parent) | |
631 | list_add(&p->ptrace_list, &p->real_parent->ptrace_children); | |
632 | } else { | |
633 | /* If this child is being traced, then we're the one tracing it | |
634 | * anyway, so let go of it. | |
635 | */ | |
636 | p->ptrace = 0; | |
637 | remove_parent(p); | |
638 | p->parent = p->real_parent; | |
639 | add_parent(p); | |
640 | ||
641 | if (task_is_traced(p)) { | |
642 | /* | |
643 | * If it was at a trace stop, turn it into | |
644 | * a normal stop since it's no longer being | |
645 | * traced. | |
646 | */ | |
647 | ptrace_untrace(p); | |
648 | } | |
649 | } | |
650 | ||
651 | /* If this is a threaded reparent there is no need to | |
652 | * notify anyone anything has happened. | |
653 | */ | |
654 | if (p->real_parent->group_leader == father->group_leader) | |
655 | return; | |
656 | ||
657 | /* We don't want people slaying init. */ | |
658 | if (p->exit_signal != -1) | |
659 | p->exit_signal = SIGCHLD; | |
660 | ||
661 | /* If we'd notified the old parent about this child's death, | |
662 | * also notify the new parent. | |
663 | */ | |
664 | if (!traced && p->exit_state == EXIT_ZOMBIE && | |
665 | p->exit_signal != -1 && thread_group_empty(p)) | |
666 | do_notify_parent(p, p->exit_signal); | |
667 | ||
668 | kill_orphaned_pgrp(p, father); | |
669 | } | |
670 | ||
671 | /* | |
672 | * When we die, we re-parent all our children. | |
673 | * Try to give them to another thread in our thread | |
674 | * group, and if no such member exists, give it to | |
675 | * the child reaper process (ie "init") in our pid | |
676 | * space. | |
677 | */ | |
678 | static void forget_original_parent(struct task_struct *father) | |
679 | { | |
680 | struct task_struct *p, *n, *reaper = father; | |
681 | struct list_head ptrace_dead; | |
682 | ||
683 | INIT_LIST_HEAD(&ptrace_dead); | |
684 | ||
685 | write_lock_irq(&tasklist_lock); | |
686 | ||
687 | do { | |
688 | reaper = next_thread(reaper); | |
689 | if (reaper == father) { | |
690 | reaper = task_child_reaper(father); | |
691 | break; | |
692 | } | |
693 | } while (reaper->flags & PF_EXITING); | |
694 | ||
695 | /* | |
696 | * There are only two places where our children can be: | |
697 | * | |
698 | * - in our child list | |
699 | * - in our ptraced child list | |
700 | * | |
701 | * Search them and reparent children. | |
702 | */ | |
703 | list_for_each_entry_safe(p, n, &father->children, sibling) { | |
704 | int ptrace; | |
705 | ||
706 | ptrace = p->ptrace; | |
707 | ||
708 | /* if father isn't the real parent, then ptrace must be enabled */ | |
709 | BUG_ON(father != p->real_parent && !ptrace); | |
710 | ||
711 | if (father == p->real_parent) { | |
712 | /* reparent with a reaper, real father it's us */ | |
713 | p->real_parent = reaper; | |
714 | reparent_thread(p, father, 0); | |
715 | } else { | |
716 | /* reparent ptraced task to its real parent */ | |
717 | __ptrace_unlink (p); | |
718 | if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 && | |
719 | thread_group_empty(p)) | |
720 | do_notify_parent(p, p->exit_signal); | |
721 | } | |
722 | ||
723 | /* | |
724 | * if the ptraced child is a zombie with exit_signal == -1 | |
725 | * we must collect it before we exit, or it will remain | |
726 | * zombie forever since we prevented it from self-reap itself | |
727 | * while it was being traced by us, to be able to see it in wait4. | |
728 | */ | |
729 | if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1)) | |
730 | list_add(&p->ptrace_list, &ptrace_dead); | |
731 | } | |
732 | ||
733 | list_for_each_entry_safe(p, n, &father->ptrace_children, ptrace_list) { | |
734 | p->real_parent = reaper; | |
735 | reparent_thread(p, father, 1); | |
736 | } | |
737 | ||
738 | write_unlock_irq(&tasklist_lock); | |
739 | BUG_ON(!list_empty(&father->children)); | |
740 | BUG_ON(!list_empty(&father->ptrace_children)); | |
741 | ||
742 | list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_list) { | |
743 | list_del_init(&p->ptrace_list); | |
744 | release_task(p); | |
745 | } | |
746 | ||
747 | } | |
748 | ||
749 | /* | |
750 | * Send signals to all our closest relatives so that they know | |
751 | * to properly mourn us.. | |
752 | */ | |
753 | static void exit_notify(struct task_struct *tsk, int group_dead) | |
754 | { | |
755 | int state; | |
756 | ||
757 | /* | |
758 | * This does two things: | |
759 | * | |
760 | * A. Make init inherit all the child processes | |
761 | * B. Check to see if any process groups have become orphaned | |
762 | * as a result of our exiting, and if they have any stopped | |
763 | * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) | |
764 | */ | |
765 | forget_original_parent(tsk); | |
766 | exit_task_namespaces(tsk); | |
767 | ||
768 | write_lock_irq(&tasklist_lock); | |
769 | if (group_dead) | |
770 | kill_orphaned_pgrp(tsk->group_leader, NULL); | |
771 | ||
772 | /* Let father know we died | |
773 | * | |
774 | * Thread signals are configurable, but you aren't going to use | |
775 | * that to send signals to arbitary processes. | |
776 | * That stops right now. | |
777 | * | |
778 | * If the parent exec id doesn't match the exec id we saved | |
779 | * when we started then we know the parent has changed security | |
780 | * domain. | |
781 | * | |
782 | * If our self_exec id doesn't match our parent_exec_id then | |
783 | * we have changed execution domain as these two values started | |
784 | * the same after a fork. | |
785 | */ | |
786 | if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 && | |
787 | (tsk->parent_exec_id != tsk->real_parent->self_exec_id || | |
788 | tsk->self_exec_id != tsk->parent_exec_id) | |
789 | && !capable(CAP_KILL)) | |
790 | tsk->exit_signal = SIGCHLD; | |
791 | ||
792 | ||
793 | /* If something other than our normal parent is ptracing us, then | |
794 | * send it a SIGCHLD instead of honoring exit_signal. exit_signal | |
795 | * only has special meaning to our real parent. | |
796 | */ | |
797 | if (tsk->exit_signal != -1 && thread_group_empty(tsk)) { | |
798 | int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD; | |
799 | do_notify_parent(tsk, signal); | |
800 | } else if (tsk->ptrace) { | |
801 | do_notify_parent(tsk, SIGCHLD); | |
802 | } | |
803 | ||
804 | state = EXIT_ZOMBIE; | |
805 | if (tsk->exit_signal == -1 && likely(!tsk->ptrace)) | |
806 | state = EXIT_DEAD; | |
807 | tsk->exit_state = state; | |
808 | ||
809 | if (thread_group_leader(tsk) && | |
810 | tsk->signal->notify_count < 0 && | |
811 | tsk->signal->group_exit_task) | |
812 | wake_up_process(tsk->signal->group_exit_task); | |
813 | ||
814 | write_unlock_irq(&tasklist_lock); | |
815 | ||
816 | /* If the process is dead, release it - nobody will wait for it */ | |
817 | if (state == EXIT_DEAD) | |
818 | release_task(tsk); | |
819 | } | |
820 | ||
821 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
822 | static void check_stack_usage(void) | |
823 | { | |
824 | static DEFINE_SPINLOCK(low_water_lock); | |
825 | static int lowest_to_date = THREAD_SIZE; | |
826 | unsigned long *n = end_of_stack(current); | |
827 | unsigned long free; | |
828 | ||
829 | while (*n == 0) | |
830 | n++; | |
831 | free = (unsigned long)n - (unsigned long)end_of_stack(current); | |
832 | ||
833 | if (free >= lowest_to_date) | |
834 | return; | |
835 | ||
836 | spin_lock(&low_water_lock); | |
837 | if (free < lowest_to_date) { | |
838 | printk(KERN_WARNING "%s used greatest stack depth: %lu bytes " | |
839 | "left\n", | |
840 | current->comm, free); | |
841 | lowest_to_date = free; | |
842 | } | |
843 | spin_unlock(&low_water_lock); | |
844 | } | |
845 | #else | |
846 | static inline void check_stack_usage(void) {} | |
847 | #endif | |
848 | ||
849 | static inline void exit_child_reaper(struct task_struct *tsk) | |
850 | { | |
851 | if (likely(tsk->group_leader != task_child_reaper(tsk))) | |
852 | return; | |
853 | ||
854 | if (tsk->nsproxy->pid_ns == &init_pid_ns) | |
855 | panic("Attempted to kill init!"); | |
856 | ||
857 | /* | |
858 | * @tsk is the last thread in the 'cgroup-init' and is exiting. | |
859 | * Terminate all remaining processes in the namespace and reap them | |
860 | * before exiting @tsk. | |
861 | * | |
862 | * Note that @tsk (last thread of cgroup-init) may not necessarily | |
863 | * be the child-reaper (i.e main thread of cgroup-init) of the | |
864 | * namespace i.e the child_reaper may have already exited. | |
865 | * | |
866 | * Even after a child_reaper exits, we let it inherit orphaned children, | |
867 | * because, pid_ns->child_reaper remains valid as long as there is | |
868 | * at least one living sub-thread in the cgroup init. | |
869 | ||
870 | * This living sub-thread of the cgroup-init will be notified when | |
871 | * a child inherited by the 'child-reaper' exits (do_notify_parent() | |
872 | * uses __group_send_sig_info()). Further, when reaping child processes, | |
873 | * do_wait() iterates over children of all living sub threads. | |
874 | ||
875 | * i.e even though 'child_reaper' thread is listed as the parent of the | |
876 | * orphaned children, any living sub-thread in the cgroup-init can | |
877 | * perform the role of the child_reaper. | |
878 | */ | |
879 | zap_pid_ns_processes(tsk->nsproxy->pid_ns); | |
880 | } | |
881 | ||
882 | NORET_TYPE void do_exit(long code) | |
883 | { | |
884 | struct task_struct *tsk = current; | |
885 | int group_dead; | |
886 | ||
887 | profile_task_exit(tsk); | |
888 | ||
889 | WARN_ON(atomic_read(&tsk->fs_excl)); | |
890 | ||
891 | if (unlikely(in_interrupt())) | |
892 | panic("Aiee, killing interrupt handler!"); | |
893 | if (unlikely(!tsk->pid)) | |
894 | panic("Attempted to kill the idle task!"); | |
895 | ||
896 | if (unlikely(current->ptrace & PT_TRACE_EXIT)) { | |
897 | current->ptrace_message = code; | |
898 | ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP); | |
899 | } | |
900 | ||
901 | /* | |
902 | * We're taking recursive faults here in do_exit. Safest is to just | |
903 | * leave this task alone and wait for reboot. | |
904 | */ | |
905 | if (unlikely(tsk->flags & PF_EXITING)) { | |
906 | printk(KERN_ALERT | |
907 | "Fixing recursive fault but reboot is needed!\n"); | |
908 | /* | |
909 | * We can do this unlocked here. The futex code uses | |
910 | * this flag just to verify whether the pi state | |
911 | * cleanup has been done or not. In the worst case it | |
912 | * loops once more. We pretend that the cleanup was | |
913 | * done as there is no way to return. Either the | |
914 | * OWNER_DIED bit is set by now or we push the blocked | |
915 | * task into the wait for ever nirwana as well. | |
916 | */ | |
917 | tsk->flags |= PF_EXITPIDONE; | |
918 | if (tsk->io_context) | |
919 | exit_io_context(); | |
920 | set_current_state(TASK_UNINTERRUPTIBLE); | |
921 | schedule(); | |
922 | } | |
923 | ||
924 | exit_signals(tsk); /* sets PF_EXITING */ | |
925 | /* | |
926 | * tsk->flags are checked in the futex code to protect against | |
927 | * an exiting task cleaning up the robust pi futexes. | |
928 | */ | |
929 | smp_mb(); | |
930 | spin_unlock_wait(&tsk->pi_lock); | |
931 | ||
932 | if (unlikely(in_atomic())) | |
933 | printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", | |
934 | current->comm, task_pid_nr(current), | |
935 | preempt_count()); | |
936 | ||
937 | acct_update_integrals(tsk); | |
938 | if (tsk->mm) { | |
939 | update_hiwater_rss(tsk->mm); | |
940 | update_hiwater_vm(tsk->mm); | |
941 | } | |
942 | group_dead = atomic_dec_and_test(&tsk->signal->live); | |
943 | if (group_dead) { | |
944 | exit_child_reaper(tsk); | |
945 | hrtimer_cancel(&tsk->signal->real_timer); | |
946 | exit_itimers(tsk->signal); | |
947 | } | |
948 | acct_collect(code, group_dead); | |
949 | #ifdef CONFIG_FUTEX | |
950 | if (unlikely(tsk->robust_list)) | |
951 | exit_robust_list(tsk); | |
952 | #ifdef CONFIG_COMPAT | |
953 | if (unlikely(tsk->compat_robust_list)) | |
954 | compat_exit_robust_list(tsk); | |
955 | #endif | |
956 | #endif | |
957 | if (group_dead) | |
958 | tty_audit_exit(); | |
959 | if (unlikely(tsk->audit_context)) | |
960 | audit_free(tsk); | |
961 | ||
962 | tsk->exit_code = code; | |
963 | taskstats_exit(tsk, group_dead); | |
964 | ||
965 | exit_mm(tsk); | |
966 | ||
967 | if (group_dead) | |
968 | acct_process(); | |
969 | exit_sem(tsk); | |
970 | __exit_files(tsk); | |
971 | __exit_fs(tsk); | |
972 | check_stack_usage(); | |
973 | exit_thread(); | |
974 | cgroup_exit(tsk, 1); | |
975 | exit_keys(tsk); | |
976 | ||
977 | if (group_dead && tsk->signal->leader) | |
978 | disassociate_ctty(1); | |
979 | ||
980 | module_put(task_thread_info(tsk)->exec_domain->module); | |
981 | if (tsk->binfmt) | |
982 | module_put(tsk->binfmt->module); | |
983 | ||
984 | proc_exit_connector(tsk); | |
985 | exit_notify(tsk, group_dead); | |
986 | #ifdef CONFIG_NUMA | |
987 | mpol_free(tsk->mempolicy); | |
988 | tsk->mempolicy = NULL; | |
989 | #endif | |
990 | #ifdef CONFIG_FUTEX | |
991 | /* | |
992 | * This must happen late, after the PID is not | |
993 | * hashed anymore: | |
994 | */ | |
995 | if (unlikely(!list_empty(&tsk->pi_state_list))) | |
996 | exit_pi_state_list(tsk); | |
997 | if (unlikely(current->pi_state_cache)) | |
998 | kfree(current->pi_state_cache); | |
999 | #endif | |
1000 | /* | |
1001 | * Make sure we are holding no locks: | |
1002 | */ | |
1003 | debug_check_no_locks_held(tsk); | |
1004 | /* | |
1005 | * We can do this unlocked here. The futex code uses this flag | |
1006 | * just to verify whether the pi state cleanup has been done | |
1007 | * or not. In the worst case it loops once more. | |
1008 | */ | |
1009 | tsk->flags |= PF_EXITPIDONE; | |
1010 | ||
1011 | if (tsk->io_context) | |
1012 | exit_io_context(); | |
1013 | ||
1014 | if (tsk->splice_pipe) | |
1015 | __free_pipe_info(tsk->splice_pipe); | |
1016 | ||
1017 | preempt_disable(); | |
1018 | /* causes final put_task_struct in finish_task_switch(). */ | |
1019 | tsk->state = TASK_DEAD; | |
1020 | ||
1021 | schedule(); | |
1022 | BUG(); | |
1023 | /* Avoid "noreturn function does return". */ | |
1024 | for (;;) | |
1025 | cpu_relax(); /* For when BUG is null */ | |
1026 | } | |
1027 | ||
1028 | EXPORT_SYMBOL_GPL(do_exit); | |
1029 | ||
1030 | NORET_TYPE void complete_and_exit(struct completion *comp, long code) | |
1031 | { | |
1032 | if (comp) | |
1033 | complete(comp); | |
1034 | ||
1035 | do_exit(code); | |
1036 | } | |
1037 | ||
1038 | EXPORT_SYMBOL(complete_and_exit); | |
1039 | ||
1040 | asmlinkage long sys_exit(int error_code) | |
1041 | { | |
1042 | do_exit((error_code&0xff)<<8); | |
1043 | } | |
1044 | ||
1045 | /* | |
1046 | * Take down every thread in the group. This is called by fatal signals | |
1047 | * as well as by sys_exit_group (below). | |
1048 | */ | |
1049 | NORET_TYPE void | |
1050 | do_group_exit(int exit_code) | |
1051 | { | |
1052 | BUG_ON(exit_code & 0x80); /* core dumps don't get here */ | |
1053 | ||
1054 | if (current->signal->flags & SIGNAL_GROUP_EXIT) | |
1055 | exit_code = current->signal->group_exit_code; | |
1056 | else if (!thread_group_empty(current)) { | |
1057 | struct signal_struct *const sig = current->signal; | |
1058 | struct sighand_struct *const sighand = current->sighand; | |
1059 | spin_lock_irq(&sighand->siglock); | |
1060 | if (signal_group_exit(sig)) | |
1061 | /* Another thread got here before we took the lock. */ | |
1062 | exit_code = sig->group_exit_code; | |
1063 | else { | |
1064 | sig->group_exit_code = exit_code; | |
1065 | sig->flags = SIGNAL_GROUP_EXIT; | |
1066 | zap_other_threads(current); | |
1067 | } | |
1068 | spin_unlock_irq(&sighand->siglock); | |
1069 | } | |
1070 | ||
1071 | do_exit(exit_code); | |
1072 | /* NOTREACHED */ | |
1073 | } | |
1074 | ||
1075 | /* | |
1076 | * this kills every thread in the thread group. Note that any externally | |
1077 | * wait4()-ing process will get the correct exit code - even if this | |
1078 | * thread is not the thread group leader. | |
1079 | */ | |
1080 | asmlinkage void sys_exit_group(int error_code) | |
1081 | { | |
1082 | do_group_exit((error_code & 0xff) << 8); | |
1083 | } | |
1084 | ||
1085 | static struct pid *task_pid_type(struct task_struct *task, enum pid_type type) | |
1086 | { | |
1087 | struct pid *pid = NULL; | |
1088 | if (type == PIDTYPE_PID) | |
1089 | pid = task->pids[type].pid; | |
1090 | else if (type < PIDTYPE_MAX) | |
1091 | pid = task->group_leader->pids[type].pid; | |
1092 | return pid; | |
1093 | } | |
1094 | ||
1095 | static int eligible_child(enum pid_type type, struct pid *pid, int options, | |
1096 | struct task_struct *p) | |
1097 | { | |
1098 | int err; | |
1099 | ||
1100 | if (type < PIDTYPE_MAX) { | |
1101 | if (task_pid_type(p, type) != pid) | |
1102 | return 0; | |
1103 | } | |
1104 | ||
1105 | /* | |
1106 | * Do not consider detached threads that are | |
1107 | * not ptraced: | |
1108 | */ | |
1109 | if (p->exit_signal == -1 && !p->ptrace) | |
1110 | return 0; | |
1111 | ||
1112 | /* Wait for all children (clone and not) if __WALL is set; | |
1113 | * otherwise, wait for clone children *only* if __WCLONE is | |
1114 | * set; otherwise, wait for non-clone children *only*. (Note: | |
1115 | * A "clone" child here is one that reports to its parent | |
1116 | * using a signal other than SIGCHLD.) */ | |
1117 | if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0)) | |
1118 | && !(options & __WALL)) | |
1119 | return 0; | |
1120 | ||
1121 | err = security_task_wait(p); | |
1122 | if (likely(!err)) | |
1123 | return 1; | |
1124 | ||
1125 | if (type != PIDTYPE_PID) | |
1126 | return 0; | |
1127 | /* This child was explicitly requested, abort */ | |
1128 | read_unlock(&tasklist_lock); | |
1129 | return err; | |
1130 | } | |
1131 | ||
1132 | static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid, | |
1133 | int why, int status, | |
1134 | struct siginfo __user *infop, | |
1135 | struct rusage __user *rusagep) | |
1136 | { | |
1137 | int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0; | |
1138 | ||
1139 | put_task_struct(p); | |
1140 | if (!retval) | |
1141 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1142 | if (!retval) | |
1143 | retval = put_user(0, &infop->si_errno); | |
1144 | if (!retval) | |
1145 | retval = put_user((short)why, &infop->si_code); | |
1146 | if (!retval) | |
1147 | retval = put_user(pid, &infop->si_pid); | |
1148 | if (!retval) | |
1149 | retval = put_user(uid, &infop->si_uid); | |
1150 | if (!retval) | |
1151 | retval = put_user(status, &infop->si_status); | |
1152 | if (!retval) | |
1153 | retval = pid; | |
1154 | return retval; | |
1155 | } | |
1156 | ||
1157 | /* | |
1158 | * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold | |
1159 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1160 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1161 | * released the lock and the system call should return. | |
1162 | */ | |
1163 | static int wait_task_zombie(struct task_struct *p, int noreap, | |
1164 | struct siginfo __user *infop, | |
1165 | int __user *stat_addr, struct rusage __user *ru) | |
1166 | { | |
1167 | unsigned long state; | |
1168 | int retval, status, traced; | |
1169 | pid_t pid = task_pid_vnr(p); | |
1170 | ||
1171 | if (unlikely(noreap)) { | |
1172 | uid_t uid = p->uid; | |
1173 | int exit_code = p->exit_code; | |
1174 | int why, status; | |
1175 | ||
1176 | get_task_struct(p); | |
1177 | read_unlock(&tasklist_lock); | |
1178 | if ((exit_code & 0x7f) == 0) { | |
1179 | why = CLD_EXITED; | |
1180 | status = exit_code >> 8; | |
1181 | } else { | |
1182 | why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED; | |
1183 | status = exit_code & 0x7f; | |
1184 | } | |
1185 | return wait_noreap_copyout(p, pid, uid, why, | |
1186 | status, infop, ru); | |
1187 | } | |
1188 | ||
1189 | /* | |
1190 | * Try to move the task's state to DEAD | |
1191 | * only one thread is allowed to do this: | |
1192 | */ | |
1193 | state = xchg(&p->exit_state, EXIT_DEAD); | |
1194 | if (state != EXIT_ZOMBIE) { | |
1195 | BUG_ON(state != EXIT_DEAD); | |
1196 | return 0; | |
1197 | } | |
1198 | ||
1199 | /* traced means p->ptrace, but not vice versa */ | |
1200 | traced = (p->real_parent != p->parent); | |
1201 | ||
1202 | if (likely(!traced)) { | |
1203 | struct signal_struct *psig; | |
1204 | struct signal_struct *sig; | |
1205 | ||
1206 | /* | |
1207 | * The resource counters for the group leader are in its | |
1208 | * own task_struct. Those for dead threads in the group | |
1209 | * are in its signal_struct, as are those for the child | |
1210 | * processes it has previously reaped. All these | |
1211 | * accumulate in the parent's signal_struct c* fields. | |
1212 | * | |
1213 | * We don't bother to take a lock here to protect these | |
1214 | * p->signal fields, because they are only touched by | |
1215 | * __exit_signal, which runs with tasklist_lock | |
1216 | * write-locked anyway, and so is excluded here. We do | |
1217 | * need to protect the access to p->parent->signal fields, | |
1218 | * as other threads in the parent group can be right | |
1219 | * here reaping other children at the same time. | |
1220 | */ | |
1221 | spin_lock_irq(&p->parent->sighand->siglock); | |
1222 | psig = p->parent->signal; | |
1223 | sig = p->signal; | |
1224 | psig->cutime = | |
1225 | cputime_add(psig->cutime, | |
1226 | cputime_add(p->utime, | |
1227 | cputime_add(sig->utime, | |
1228 | sig->cutime))); | |
1229 | psig->cstime = | |
1230 | cputime_add(psig->cstime, | |
1231 | cputime_add(p->stime, | |
1232 | cputime_add(sig->stime, | |
1233 | sig->cstime))); | |
1234 | psig->cgtime = | |
1235 | cputime_add(psig->cgtime, | |
1236 | cputime_add(p->gtime, | |
1237 | cputime_add(sig->gtime, | |
1238 | sig->cgtime))); | |
1239 | psig->cmin_flt += | |
1240 | p->min_flt + sig->min_flt + sig->cmin_flt; | |
1241 | psig->cmaj_flt += | |
1242 | p->maj_flt + sig->maj_flt + sig->cmaj_flt; | |
1243 | psig->cnvcsw += | |
1244 | p->nvcsw + sig->nvcsw + sig->cnvcsw; | |
1245 | psig->cnivcsw += | |
1246 | p->nivcsw + sig->nivcsw + sig->cnivcsw; | |
1247 | psig->cinblock += | |
1248 | task_io_get_inblock(p) + | |
1249 | sig->inblock + sig->cinblock; | |
1250 | psig->coublock += | |
1251 | task_io_get_oublock(p) + | |
1252 | sig->oublock + sig->coublock; | |
1253 | spin_unlock_irq(&p->parent->sighand->siglock); | |
1254 | } | |
1255 | ||
1256 | /* | |
1257 | * Now we are sure this task is interesting, and no other | |
1258 | * thread can reap it because we set its state to EXIT_DEAD. | |
1259 | */ | |
1260 | read_unlock(&tasklist_lock); | |
1261 | ||
1262 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; | |
1263 | status = (p->signal->flags & SIGNAL_GROUP_EXIT) | |
1264 | ? p->signal->group_exit_code : p->exit_code; | |
1265 | if (!retval && stat_addr) | |
1266 | retval = put_user(status, stat_addr); | |
1267 | if (!retval && infop) | |
1268 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1269 | if (!retval && infop) | |
1270 | retval = put_user(0, &infop->si_errno); | |
1271 | if (!retval && infop) { | |
1272 | int why; | |
1273 | ||
1274 | if ((status & 0x7f) == 0) { | |
1275 | why = CLD_EXITED; | |
1276 | status >>= 8; | |
1277 | } else { | |
1278 | why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED; | |
1279 | status &= 0x7f; | |
1280 | } | |
1281 | retval = put_user((short)why, &infop->si_code); | |
1282 | if (!retval) | |
1283 | retval = put_user(status, &infop->si_status); | |
1284 | } | |
1285 | if (!retval && infop) | |
1286 | retval = put_user(pid, &infop->si_pid); | |
1287 | if (!retval && infop) | |
1288 | retval = put_user(p->uid, &infop->si_uid); | |
1289 | if (!retval) | |
1290 | retval = pid; | |
1291 | ||
1292 | if (traced) { | |
1293 | write_lock_irq(&tasklist_lock); | |
1294 | /* We dropped tasklist, ptracer could die and untrace */ | |
1295 | ptrace_unlink(p); | |
1296 | /* | |
1297 | * If this is not a detached task, notify the parent. | |
1298 | * If it's still not detached after that, don't release | |
1299 | * it now. | |
1300 | */ | |
1301 | if (p->exit_signal != -1) { | |
1302 | do_notify_parent(p, p->exit_signal); | |
1303 | if (p->exit_signal != -1) { | |
1304 | p->exit_state = EXIT_ZOMBIE; | |
1305 | p = NULL; | |
1306 | } | |
1307 | } | |
1308 | write_unlock_irq(&tasklist_lock); | |
1309 | } | |
1310 | if (p != NULL) | |
1311 | release_task(p); | |
1312 | ||
1313 | return retval; | |
1314 | } | |
1315 | ||
1316 | /* | |
1317 | * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold | |
1318 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1319 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1320 | * released the lock and the system call should return. | |
1321 | */ | |
1322 | static int wait_task_stopped(struct task_struct *p, | |
1323 | int noreap, struct siginfo __user *infop, | |
1324 | int __user *stat_addr, struct rusage __user *ru) | |
1325 | { | |
1326 | int retval, exit_code, why; | |
1327 | uid_t uid = 0; /* unneeded, required by compiler */ | |
1328 | pid_t pid; | |
1329 | ||
1330 | exit_code = 0; | |
1331 | spin_lock_irq(&p->sighand->siglock); | |
1332 | ||
1333 | if (unlikely(!task_is_stopped_or_traced(p))) | |
1334 | goto unlock_sig; | |
1335 | ||
1336 | if (!(p->ptrace & PT_PTRACED) && p->signal->group_stop_count > 0) | |
1337 | /* | |
1338 | * A group stop is in progress and this is the group leader. | |
1339 | * We won't report until all threads have stopped. | |
1340 | */ | |
1341 | goto unlock_sig; | |
1342 | ||
1343 | exit_code = p->exit_code; | |
1344 | if (!exit_code) | |
1345 | goto unlock_sig; | |
1346 | ||
1347 | if (!noreap) | |
1348 | p->exit_code = 0; | |
1349 | ||
1350 | uid = p->uid; | |
1351 | unlock_sig: | |
1352 | spin_unlock_irq(&p->sighand->siglock); | |
1353 | if (!exit_code) | |
1354 | return 0; | |
1355 | ||
1356 | /* | |
1357 | * Now we are pretty sure this task is interesting. | |
1358 | * Make sure it doesn't get reaped out from under us while we | |
1359 | * give up the lock and then examine it below. We don't want to | |
1360 | * keep holding onto the tasklist_lock while we call getrusage and | |
1361 | * possibly take page faults for user memory. | |
1362 | */ | |
1363 | get_task_struct(p); | |
1364 | pid = task_pid_vnr(p); | |
1365 | why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED; | |
1366 | read_unlock(&tasklist_lock); | |
1367 | ||
1368 | if (unlikely(noreap)) | |
1369 | return wait_noreap_copyout(p, pid, uid, | |
1370 | why, exit_code, | |
1371 | infop, ru); | |
1372 | ||
1373 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; | |
1374 | if (!retval && stat_addr) | |
1375 | retval = put_user((exit_code << 8) | 0x7f, stat_addr); | |
1376 | if (!retval && infop) | |
1377 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1378 | if (!retval && infop) | |
1379 | retval = put_user(0, &infop->si_errno); | |
1380 | if (!retval && infop) | |
1381 | retval = put_user((short)why, &infop->si_code); | |
1382 | if (!retval && infop) | |
1383 | retval = put_user(exit_code, &infop->si_status); | |
1384 | if (!retval && infop) | |
1385 | retval = put_user(pid, &infop->si_pid); | |
1386 | if (!retval && infop) | |
1387 | retval = put_user(uid, &infop->si_uid); | |
1388 | if (!retval) | |
1389 | retval = pid; | |
1390 | put_task_struct(p); | |
1391 | ||
1392 | BUG_ON(!retval); | |
1393 | return retval; | |
1394 | } | |
1395 | ||
1396 | /* | |
1397 | * Handle do_wait work for one task in a live, non-stopped state. | |
1398 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1399 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1400 | * released the lock and the system call should return. | |
1401 | */ | |
1402 | static int wait_task_continued(struct task_struct *p, int noreap, | |
1403 | struct siginfo __user *infop, | |
1404 | int __user *stat_addr, struct rusage __user *ru) | |
1405 | { | |
1406 | int retval; | |
1407 | pid_t pid; | |
1408 | uid_t uid; | |
1409 | ||
1410 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) | |
1411 | return 0; | |
1412 | ||
1413 | spin_lock_irq(&p->sighand->siglock); | |
1414 | /* Re-check with the lock held. */ | |
1415 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) { | |
1416 | spin_unlock_irq(&p->sighand->siglock); | |
1417 | return 0; | |
1418 | } | |
1419 | if (!noreap) | |
1420 | p->signal->flags &= ~SIGNAL_STOP_CONTINUED; | |
1421 | spin_unlock_irq(&p->sighand->siglock); | |
1422 | ||
1423 | pid = task_pid_vnr(p); | |
1424 | uid = p->uid; | |
1425 | get_task_struct(p); | |
1426 | read_unlock(&tasklist_lock); | |
1427 | ||
1428 | if (!infop) { | |
1429 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; | |
1430 | put_task_struct(p); | |
1431 | if (!retval && stat_addr) | |
1432 | retval = put_user(0xffff, stat_addr); | |
1433 | if (!retval) | |
1434 | retval = pid; | |
1435 | } else { | |
1436 | retval = wait_noreap_copyout(p, pid, uid, | |
1437 | CLD_CONTINUED, SIGCONT, | |
1438 | infop, ru); | |
1439 | BUG_ON(retval == 0); | |
1440 | } | |
1441 | ||
1442 | return retval; | |
1443 | } | |
1444 | ||
1445 | static long do_wait(enum pid_type type, struct pid *pid, int options, | |
1446 | struct siginfo __user *infop, int __user *stat_addr, | |
1447 | struct rusage __user *ru) | |
1448 | { | |
1449 | DECLARE_WAITQUEUE(wait, current); | |
1450 | struct task_struct *tsk; | |
1451 | int flag, retval; | |
1452 | ||
1453 | add_wait_queue(¤t->signal->wait_chldexit,&wait); | |
1454 | repeat: | |
1455 | /* If there is nothing that can match our critier just get out */ | |
1456 | retval = -ECHILD; | |
1457 | if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type]))) | |
1458 | goto end; | |
1459 | ||
1460 | /* | |
1461 | * We will set this flag if we see any child that might later | |
1462 | * match our criteria, even if we are not able to reap it yet. | |
1463 | */ | |
1464 | flag = retval = 0; | |
1465 | current->state = TASK_INTERRUPTIBLE; | |
1466 | read_lock(&tasklist_lock); | |
1467 | tsk = current; | |
1468 | do { | |
1469 | struct task_struct *p; | |
1470 | ||
1471 | list_for_each_entry(p, &tsk->children, sibling) { | |
1472 | int ret = eligible_child(type, pid, options, p); | |
1473 | if (!ret) | |
1474 | continue; | |
1475 | ||
1476 | if (unlikely(ret < 0)) { | |
1477 | retval = ret; | |
1478 | } else if (task_is_stopped_or_traced(p)) { | |
1479 | /* | |
1480 | * It's stopped now, so it might later | |
1481 | * continue, exit, or stop again. | |
1482 | */ | |
1483 | flag = 1; | |
1484 | if (!(p->ptrace & PT_PTRACED) && | |
1485 | !(options & WUNTRACED)) | |
1486 | continue; | |
1487 | ||
1488 | retval = wait_task_stopped(p, | |
1489 | (options & WNOWAIT), infop, | |
1490 | stat_addr, ru); | |
1491 | } else if (p->exit_state == EXIT_ZOMBIE && | |
1492 | !delay_group_leader(p)) { | |
1493 | /* | |
1494 | * We don't reap group leaders with subthreads. | |
1495 | */ | |
1496 | if (!likely(options & WEXITED)) | |
1497 | continue; | |
1498 | retval = wait_task_zombie(p, | |
1499 | (options & WNOWAIT), infop, | |
1500 | stat_addr, ru); | |
1501 | } else if (p->exit_state != EXIT_DEAD) { | |
1502 | /* | |
1503 | * It's running now, so it might later | |
1504 | * exit, stop, or stop and then continue. | |
1505 | */ | |
1506 | flag = 1; | |
1507 | if (!unlikely(options & WCONTINUED)) | |
1508 | continue; | |
1509 | retval = wait_task_continued(p, | |
1510 | (options & WNOWAIT), infop, | |
1511 | stat_addr, ru); | |
1512 | } | |
1513 | if (retval != 0) /* tasklist_lock released */ | |
1514 | goto end; | |
1515 | } | |
1516 | if (!flag) { | |
1517 | list_for_each_entry(p, &tsk->ptrace_children, | |
1518 | ptrace_list) { | |
1519 | flag = eligible_child(type, pid, options, p); | |
1520 | if (!flag) | |
1521 | continue; | |
1522 | if (likely(flag > 0)) | |
1523 | break; | |
1524 | retval = flag; | |
1525 | goto end; | |
1526 | } | |
1527 | } | |
1528 | if (options & __WNOTHREAD) | |
1529 | break; | |
1530 | tsk = next_thread(tsk); | |
1531 | BUG_ON(tsk->signal != current->signal); | |
1532 | } while (tsk != current); | |
1533 | read_unlock(&tasklist_lock); | |
1534 | ||
1535 | if (flag) { | |
1536 | if (options & WNOHANG) | |
1537 | goto end; | |
1538 | retval = -ERESTARTSYS; | |
1539 | if (signal_pending(current)) | |
1540 | goto end; | |
1541 | schedule(); | |
1542 | goto repeat; | |
1543 | } | |
1544 | retval = -ECHILD; | |
1545 | end: | |
1546 | current->state = TASK_RUNNING; | |
1547 | remove_wait_queue(¤t->signal->wait_chldexit,&wait); | |
1548 | if (infop) { | |
1549 | if (retval > 0) | |
1550 | retval = 0; | |
1551 | else { | |
1552 | /* | |
1553 | * For a WNOHANG return, clear out all the fields | |
1554 | * we would set so the user can easily tell the | |
1555 | * difference. | |
1556 | */ | |
1557 | if (!retval) | |
1558 | retval = put_user(0, &infop->si_signo); | |
1559 | if (!retval) | |
1560 | retval = put_user(0, &infop->si_errno); | |
1561 | if (!retval) | |
1562 | retval = put_user(0, &infop->si_code); | |
1563 | if (!retval) | |
1564 | retval = put_user(0, &infop->si_pid); | |
1565 | if (!retval) | |
1566 | retval = put_user(0, &infop->si_uid); | |
1567 | if (!retval) | |
1568 | retval = put_user(0, &infop->si_status); | |
1569 | } | |
1570 | } | |
1571 | return retval; | |
1572 | } | |
1573 | ||
1574 | asmlinkage long sys_waitid(int which, pid_t upid, | |
1575 | struct siginfo __user *infop, int options, | |
1576 | struct rusage __user *ru) | |
1577 | { | |
1578 | struct pid *pid = NULL; | |
1579 | enum pid_type type; | |
1580 | long ret; | |
1581 | ||
1582 | if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED)) | |
1583 | return -EINVAL; | |
1584 | if (!(options & (WEXITED|WSTOPPED|WCONTINUED))) | |
1585 | return -EINVAL; | |
1586 | ||
1587 | switch (which) { | |
1588 | case P_ALL: | |
1589 | type = PIDTYPE_MAX; | |
1590 | break; | |
1591 | case P_PID: | |
1592 | type = PIDTYPE_PID; | |
1593 | if (upid <= 0) | |
1594 | return -EINVAL; | |
1595 | break; | |
1596 | case P_PGID: | |
1597 | type = PIDTYPE_PGID; | |
1598 | if (upid <= 0) | |
1599 | return -EINVAL; | |
1600 | break; | |
1601 | default: | |
1602 | return -EINVAL; | |
1603 | } | |
1604 | ||
1605 | if (type < PIDTYPE_MAX) | |
1606 | pid = find_get_pid(upid); | |
1607 | ret = do_wait(type, pid, options, infop, NULL, ru); | |
1608 | put_pid(pid); | |
1609 | ||
1610 | /* avoid REGPARM breakage on x86: */ | |
1611 | prevent_tail_call(ret); | |
1612 | return ret; | |
1613 | } | |
1614 | ||
1615 | asmlinkage long sys_wait4(pid_t upid, int __user *stat_addr, | |
1616 | int options, struct rusage __user *ru) | |
1617 | { | |
1618 | struct pid *pid = NULL; | |
1619 | enum pid_type type; | |
1620 | long ret; | |
1621 | ||
1622 | if (options & ~(WNOHANG|WUNTRACED|WCONTINUED| | |
1623 | __WNOTHREAD|__WCLONE|__WALL)) | |
1624 | return -EINVAL; | |
1625 | ||
1626 | if (upid == -1) | |
1627 | type = PIDTYPE_MAX; | |
1628 | else if (upid < 0) { | |
1629 | type = PIDTYPE_PGID; | |
1630 | pid = find_get_pid(-upid); | |
1631 | } else if (upid == 0) { | |
1632 | type = PIDTYPE_PGID; | |
1633 | pid = get_pid(task_pgrp(current)); | |
1634 | } else /* upid > 0 */ { | |
1635 | type = PIDTYPE_PID; | |
1636 | pid = find_get_pid(upid); | |
1637 | } | |
1638 | ||
1639 | ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru); | |
1640 | put_pid(pid); | |
1641 | ||
1642 | /* avoid REGPARM breakage on x86: */ | |
1643 | prevent_tail_call(ret); | |
1644 | return ret; | |
1645 | } | |
1646 | ||
1647 | #ifdef __ARCH_WANT_SYS_WAITPID | |
1648 | ||
1649 | /* | |
1650 | * sys_waitpid() remains for compatibility. waitpid() should be | |
1651 | * implemented by calling sys_wait4() from libc.a. | |
1652 | */ | |
1653 | asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options) | |
1654 | { | |
1655 | return sys_wait4(pid, stat_addr, options, NULL); | |
1656 | } | |
1657 | ||
1658 | #endif |