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); | |
1da177e4 | 61 | |
408b664a AB |
62 | static void exit_mm(struct task_struct * tsk); |
63 | ||
1da177e4 LT |
64 | static void __unhash_process(struct task_struct *p) |
65 | { | |
66 | nr_threads--; | |
67 | detach_pid(p, PIDTYPE_PID); | |
1da177e4 LT |
68 | if (thread_group_leader(p)) { |
69 | detach_pid(p, PIDTYPE_PGID); | |
70 | detach_pid(p, PIDTYPE_SID); | |
c97d9893 | 71 | |
5e85d4ab | 72 | list_del_rcu(&p->tasks); |
73b9ebfe | 73 | __get_cpu_var(process_counts)--; |
1da177e4 | 74 | } |
47e65328 | 75 | list_del_rcu(&p->thread_group); |
f470021a | 76 | list_del_init(&p->sibling); |
1da177e4 LT |
77 | } |
78 | ||
6a14c5c9 ON |
79 | /* |
80 | * This function expects the tasklist_lock write-locked. | |
81 | */ | |
82 | static void __exit_signal(struct task_struct *tsk) | |
83 | { | |
84 | struct signal_struct *sig = tsk->signal; | |
85 | struct sighand_struct *sighand; | |
86 | ||
87 | BUG_ON(!sig); | |
88 | BUG_ON(!atomic_read(&sig->count)); | |
89 | ||
6a14c5c9 ON |
90 | sighand = rcu_dereference(tsk->sighand); |
91 | spin_lock(&sighand->siglock); | |
92 | ||
93 | posix_cpu_timers_exit(tsk); | |
94 | if (atomic_dec_and_test(&sig->count)) | |
95 | posix_cpu_timers_exit_group(tsk); | |
96 | else { | |
97 | /* | |
98 | * If there is any task waiting for the group exit | |
99 | * then notify it: | |
100 | */ | |
6db840fa | 101 | if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) |
6a14c5c9 | 102 | wake_up_process(sig->group_exit_task); |
6db840fa | 103 | |
6a14c5c9 ON |
104 | if (tsk == sig->curr_target) |
105 | sig->curr_target = next_thread(tsk); | |
106 | /* | |
107 | * Accumulate here the counters for all threads but the | |
108 | * group leader as they die, so they can be added into | |
109 | * the process-wide totals when those are taken. | |
110 | * The group leader stays around as a zombie as long | |
111 | * as there are other threads. When it gets reaped, | |
112 | * the exit.c code will add its counts into these totals. | |
113 | * We won't ever get here for the group leader, since it | |
114 | * will have been the last reference on the signal_struct. | |
115 | */ | |
32bd671d PZ |
116 | sig->utime = cputime_add(sig->utime, task_utime(tsk)); |
117 | sig->stime = cputime_add(sig->stime, task_stime(tsk)); | |
49048622 | 118 | sig->gtime = cputime_add(sig->gtime, task_gtime(tsk)); |
6a14c5c9 ON |
119 | sig->min_flt += tsk->min_flt; |
120 | sig->maj_flt += tsk->maj_flt; | |
121 | sig->nvcsw += tsk->nvcsw; | |
122 | sig->nivcsw += tsk->nivcsw; | |
6eaeeaba ED |
123 | sig->inblock += task_io_get_inblock(tsk); |
124 | sig->oublock += task_io_get_oublock(tsk); | |
5995477a | 125 | task_io_accounting_add(&sig->ioac, &tsk->ioac); |
32bd671d | 126 | sig->sum_sched_runtime += tsk->se.sum_exec_runtime; |
6a14c5c9 ON |
127 | sig = NULL; /* Marker for below. */ |
128 | } | |
129 | ||
5876700c ON |
130 | __unhash_process(tsk); |
131 | ||
da7978b0 ON |
132 | /* |
133 | * Do this under ->siglock, we can race with another thread | |
134 | * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals. | |
135 | */ | |
136 | flush_sigqueue(&tsk->pending); | |
137 | ||
6a14c5c9 | 138 | tsk->signal = NULL; |
a7e5328a | 139 | tsk->sighand = NULL; |
6a14c5c9 | 140 | spin_unlock(&sighand->siglock); |
6a14c5c9 | 141 | |
a7e5328a | 142 | __cleanup_sighand(sighand); |
6a14c5c9 | 143 | clear_tsk_thread_flag(tsk,TIF_SIGPENDING); |
6a14c5c9 ON |
144 | if (sig) { |
145 | flush_sigqueue(&sig->shared_pending); | |
093a8e8a | 146 | taskstats_tgid_free(sig); |
ad474cac ON |
147 | /* |
148 | * Make sure ->signal can't go away under rq->lock, | |
149 | * see account_group_exec_runtime(). | |
150 | */ | |
151 | task_rq_unlock_wait(tsk); | |
6a14c5c9 ON |
152 | __cleanup_signal(sig); |
153 | } | |
154 | } | |
155 | ||
8c7904a0 EB |
156 | static void delayed_put_task_struct(struct rcu_head *rhp) |
157 | { | |
0a16b607 MD |
158 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); |
159 | ||
160 | trace_sched_process_free(tsk); | |
161 | put_task_struct(tsk); | |
8c7904a0 EB |
162 | } |
163 | ||
f470021a | 164 | |
1da177e4 LT |
165 | void release_task(struct task_struct * p) |
166 | { | |
36c8b586 | 167 | struct task_struct *leader; |
1da177e4 | 168 | int zap_leader; |
1f09f974 | 169 | repeat: |
dae33574 | 170 | tracehook_prepare_release_task(p); |
c69e8d9c DH |
171 | /* don't need to get the RCU readlock here - the process is dead and |
172 | * can't be modifying its own credentials */ | |
173 | atomic_dec(&__task_cred(p)->user->processes); | |
174 | ||
60347f67 | 175 | proc_flush_task(p); |
1da177e4 | 176 | write_lock_irq(&tasklist_lock); |
dae33574 | 177 | tracehook_finish_release_task(p); |
1da177e4 | 178 | __exit_signal(p); |
35f5cad8 | 179 | |
1da177e4 LT |
180 | /* |
181 | * If we are the last non-leader member of the thread | |
182 | * group, and the leader is zombie, then notify the | |
183 | * group leader's parent process. (if it wants notification.) | |
184 | */ | |
185 | zap_leader = 0; | |
186 | leader = p->group_leader; | |
187 | if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) { | |
d839fd4d | 188 | BUG_ON(task_detached(leader)); |
1da177e4 LT |
189 | do_notify_parent(leader, leader->exit_signal); |
190 | /* | |
191 | * If we were the last child thread and the leader has | |
192 | * exited already, and the leader's parent ignores SIGCHLD, | |
193 | * then we are the one who should release the leader. | |
194 | * | |
195 | * do_notify_parent() will have marked it self-reaping in | |
196 | * that case. | |
197 | */ | |
d839fd4d | 198 | zap_leader = task_detached(leader); |
dae33574 RM |
199 | |
200 | /* | |
201 | * This maintains the invariant that release_task() | |
202 | * only runs on a task in EXIT_DEAD, just for sanity. | |
203 | */ | |
204 | if (zap_leader) | |
205 | leader->exit_state = EXIT_DEAD; | |
1da177e4 LT |
206 | } |
207 | ||
1da177e4 | 208 | write_unlock_irq(&tasklist_lock); |
1da177e4 | 209 | release_thread(p); |
8c7904a0 | 210 | call_rcu(&p->rcu, delayed_put_task_struct); |
1da177e4 LT |
211 | |
212 | p = leader; | |
213 | if (unlikely(zap_leader)) | |
214 | goto repeat; | |
215 | } | |
216 | ||
1da177e4 LT |
217 | /* |
218 | * This checks not only the pgrp, but falls back on the pid if no | |
219 | * satisfactory pgrp is found. I dunno - gdb doesn't work correctly | |
220 | * without this... | |
04a2e6a5 EB |
221 | * |
222 | * The caller must hold rcu lock or the tasklist lock. | |
1da177e4 | 223 | */ |
04a2e6a5 | 224 | struct pid *session_of_pgrp(struct pid *pgrp) |
1da177e4 LT |
225 | { |
226 | struct task_struct *p; | |
04a2e6a5 | 227 | struct pid *sid = NULL; |
62dfb554 | 228 | |
04a2e6a5 | 229 | p = pid_task(pgrp, PIDTYPE_PGID); |
62dfb554 | 230 | if (p == NULL) |
04a2e6a5 | 231 | p = pid_task(pgrp, PIDTYPE_PID); |
62dfb554 | 232 | if (p != NULL) |
04a2e6a5 | 233 | sid = task_session(p); |
62dfb554 | 234 | |
1da177e4 LT |
235 | return sid; |
236 | } | |
237 | ||
238 | /* | |
239 | * Determine if a process group is "orphaned", according to the POSIX | |
240 | * definition in 2.2.2.52. Orphaned process groups are not to be affected | |
241 | * by terminal-generated stop signals. Newly orphaned process groups are | |
242 | * to receive a SIGHUP and a SIGCONT. | |
243 | * | |
244 | * "I ask you, have you ever known what it is to be an orphan?" | |
245 | */ | |
0475ac08 | 246 | static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task) |
1da177e4 LT |
247 | { |
248 | struct task_struct *p; | |
1da177e4 | 249 | |
0475ac08 | 250 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
05e83df6 ON |
251 | if ((p == ignored_task) || |
252 | (p->exit_state && thread_group_empty(p)) || | |
253 | is_global_init(p->real_parent)) | |
1da177e4 | 254 | continue; |
05e83df6 | 255 | |
0475ac08 | 256 | if (task_pgrp(p->real_parent) != pgrp && |
05e83df6 ON |
257 | task_session(p->real_parent) == task_session(p)) |
258 | return 0; | |
0475ac08 | 259 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
05e83df6 ON |
260 | |
261 | return 1; | |
1da177e4 LT |
262 | } |
263 | ||
3e7cd6c4 | 264 | int is_current_pgrp_orphaned(void) |
1da177e4 LT |
265 | { |
266 | int retval; | |
267 | ||
268 | read_lock(&tasklist_lock); | |
3e7cd6c4 | 269 | retval = will_become_orphaned_pgrp(task_pgrp(current), NULL); |
1da177e4 LT |
270 | read_unlock(&tasklist_lock); |
271 | ||
272 | return retval; | |
273 | } | |
274 | ||
0475ac08 | 275 | static int has_stopped_jobs(struct pid *pgrp) |
1da177e4 LT |
276 | { |
277 | int retval = 0; | |
278 | struct task_struct *p; | |
279 | ||
0475ac08 | 280 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
338077e5 | 281 | if (!task_is_stopped(p)) |
1da177e4 | 282 | continue; |
1da177e4 LT |
283 | retval = 1; |
284 | break; | |
0475ac08 | 285 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
286 | return retval; |
287 | } | |
288 | ||
f49ee505 ON |
289 | /* |
290 | * Check to see if any process groups have become orphaned as | |
291 | * a result of our exiting, and if they have any stopped jobs, | |
292 | * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) | |
293 | */ | |
294 | static void | |
295 | kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) | |
296 | { | |
297 | struct pid *pgrp = task_pgrp(tsk); | |
298 | struct task_struct *ignored_task = tsk; | |
299 | ||
300 | if (!parent) | |
301 | /* exit: our father is in a different pgrp than | |
302 | * we are and we were the only connection outside. | |
303 | */ | |
304 | parent = tsk->real_parent; | |
305 | else | |
306 | /* reparent: our child is in a different pgrp than | |
307 | * we are, and it was the only connection outside. | |
308 | */ | |
309 | ignored_task = NULL; | |
310 | ||
311 | if (task_pgrp(parent) != pgrp && | |
312 | task_session(parent) == task_session(tsk) && | |
313 | will_become_orphaned_pgrp(pgrp, ignored_task) && | |
314 | has_stopped_jobs(pgrp)) { | |
315 | __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp); | |
316 | __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp); | |
317 | } | |
318 | } | |
319 | ||
1da177e4 | 320 | /** |
49d769d5 | 321 | * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd |
1da177e4 LT |
322 | * |
323 | * If a kernel thread is launched as a result of a system call, or if | |
49d769d5 EB |
324 | * it ever exits, it should generally reparent itself to kthreadd so it |
325 | * isn't in the way of other processes and is correctly cleaned up on exit. | |
1da177e4 LT |
326 | * |
327 | * The various task state such as scheduling policy and priority may have | |
328 | * been inherited from a user process, so we reset them to sane values here. | |
329 | * | |
49d769d5 | 330 | * NOTE that reparent_to_kthreadd() gives the caller full capabilities. |
1da177e4 | 331 | */ |
49d769d5 | 332 | static void reparent_to_kthreadd(void) |
1da177e4 LT |
333 | { |
334 | write_lock_irq(&tasklist_lock); | |
335 | ||
336 | ptrace_unlink(current); | |
337 | /* Reparent to init */ | |
49d769d5 | 338 | current->real_parent = current->parent = kthreadd_task; |
f470021a | 339 | list_move_tail(¤t->sibling, ¤t->real_parent->children); |
1da177e4 LT |
340 | |
341 | /* Set the exit signal to SIGCHLD so we signal init on exit */ | |
342 | current->exit_signal = SIGCHLD; | |
343 | ||
e05606d3 | 344 | if (task_nice(current) < 0) |
1da177e4 LT |
345 | set_user_nice(current, 0); |
346 | /* cpus_allowed? */ | |
347 | /* rt_priority? */ | |
348 | /* signals? */ | |
1da177e4 LT |
349 | memcpy(current->signal->rlim, init_task.signal->rlim, |
350 | sizeof(current->signal->rlim)); | |
d84f4f99 DH |
351 | |
352 | atomic_inc(&init_cred.usage); | |
353 | commit_creds(&init_cred); | |
1da177e4 | 354 | write_unlock_irq(&tasklist_lock); |
1da177e4 LT |
355 | } |
356 | ||
8520d7c7 | 357 | void __set_special_pids(struct pid *pid) |
1da177e4 | 358 | { |
e19f247a | 359 | struct task_struct *curr = current->group_leader; |
8520d7c7 | 360 | pid_t nr = pid_nr(pid); |
1da177e4 | 361 | |
8520d7c7 | 362 | if (task_session(curr) != pid) { |
7d8da096 | 363 | change_pid(curr, PIDTYPE_SID, pid); |
8520d7c7 | 364 | set_task_session(curr, nr); |
1da177e4 | 365 | } |
8520d7c7 | 366 | if (task_pgrp(curr) != pid) { |
7d8da096 | 367 | change_pid(curr, PIDTYPE_PGID, pid); |
8520d7c7 | 368 | set_task_pgrp(curr, nr); |
1da177e4 LT |
369 | } |
370 | } | |
371 | ||
8520d7c7 | 372 | static void set_special_pids(struct pid *pid) |
1da177e4 LT |
373 | { |
374 | write_lock_irq(&tasklist_lock); | |
8520d7c7 | 375 | __set_special_pids(pid); |
1da177e4 LT |
376 | write_unlock_irq(&tasklist_lock); |
377 | } | |
378 | ||
379 | /* | |
380 | * Let kernel threads use this to say that they | |
381 | * allow a certain signal (since daemonize() will | |
382 | * have disabled all of them by default). | |
383 | */ | |
384 | int allow_signal(int sig) | |
385 | { | |
7ed20e1a | 386 | if (!valid_signal(sig) || sig < 1) |
1da177e4 LT |
387 | return -EINVAL; |
388 | ||
389 | spin_lock_irq(¤t->sighand->siglock); | |
390 | sigdelset(¤t->blocked, sig); | |
391 | if (!current->mm) { | |
392 | /* Kernel threads handle their own signals. | |
393 | Let the signal code know it'll be handled, so | |
394 | that they don't get converted to SIGKILL or | |
395 | just silently dropped */ | |
396 | current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; | |
397 | } | |
398 | recalc_sigpending(); | |
399 | spin_unlock_irq(¤t->sighand->siglock); | |
400 | return 0; | |
401 | } | |
402 | ||
403 | EXPORT_SYMBOL(allow_signal); | |
404 | ||
405 | int disallow_signal(int sig) | |
406 | { | |
7ed20e1a | 407 | if (!valid_signal(sig) || sig < 1) |
1da177e4 LT |
408 | return -EINVAL; |
409 | ||
410 | spin_lock_irq(¤t->sighand->siglock); | |
10ab825b | 411 | current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; |
1da177e4 LT |
412 | recalc_sigpending(); |
413 | spin_unlock_irq(¤t->sighand->siglock); | |
414 | return 0; | |
415 | } | |
416 | ||
417 | EXPORT_SYMBOL(disallow_signal); | |
418 | ||
419 | /* | |
420 | * Put all the gunge required to become a kernel thread without | |
421 | * attached user resources in one place where it belongs. | |
422 | */ | |
423 | ||
424 | void daemonize(const char *name, ...) | |
425 | { | |
426 | va_list args; | |
427 | struct fs_struct *fs; | |
428 | sigset_t blocked; | |
429 | ||
430 | va_start(args, name); | |
431 | vsnprintf(current->comm, sizeof(current->comm), name, args); | |
432 | va_end(args); | |
433 | ||
434 | /* | |
435 | * If we were started as result of loading a module, close all of the | |
436 | * user space pages. We don't need them, and if we didn't close them | |
437 | * they would be locked into memory. | |
438 | */ | |
439 | exit_mm(current); | |
83144186 RW |
440 | /* |
441 | * We don't want to have TIF_FREEZE set if the system-wide hibernation | |
442 | * or suspend transition begins right now. | |
443 | */ | |
7b34e428 | 444 | current->flags |= (PF_NOFREEZE | PF_KTHREAD); |
1da177e4 | 445 | |
8520d7c7 ON |
446 | if (current->nsproxy != &init_nsproxy) { |
447 | get_nsproxy(&init_nsproxy); | |
448 | switch_task_namespaces(current, &init_nsproxy); | |
449 | } | |
297bd42b | 450 | set_special_pids(&init_struct_pid); |
24ec839c | 451 | proc_clear_tty(current); |
1da177e4 LT |
452 | |
453 | /* Block and flush all signals */ | |
454 | sigfillset(&blocked); | |
455 | sigprocmask(SIG_BLOCK, &blocked, NULL); | |
456 | flush_signals(current); | |
457 | ||
458 | /* Become as one with the init task */ | |
459 | ||
460 | exit_fs(current); /* current->fs->count--; */ | |
461 | fs = init_task.fs; | |
462 | current->fs = fs; | |
463 | atomic_inc(&fs->count); | |
ab516013 | 464 | |
d4c5e41f | 465 | exit_files(current); |
1da177e4 LT |
466 | current->files = init_task.files; |
467 | atomic_inc(¤t->files->count); | |
468 | ||
49d769d5 | 469 | reparent_to_kthreadd(); |
1da177e4 LT |
470 | } |
471 | ||
472 | EXPORT_SYMBOL(daemonize); | |
473 | ||
858119e1 | 474 | static void close_files(struct files_struct * files) |
1da177e4 LT |
475 | { |
476 | int i, j; | |
badf1662 | 477 | struct fdtable *fdt; |
1da177e4 LT |
478 | |
479 | j = 0; | |
4fb3a538 DS |
480 | |
481 | /* | |
482 | * It is safe to dereference the fd table without RCU or | |
483 | * ->file_lock because this is the last reference to the | |
484 | * files structure. | |
485 | */ | |
badf1662 | 486 | fdt = files_fdtable(files); |
1da177e4 LT |
487 | for (;;) { |
488 | unsigned long set; | |
489 | i = j * __NFDBITS; | |
bbea9f69 | 490 | if (i >= fdt->max_fds) |
1da177e4 | 491 | break; |
badf1662 | 492 | set = fdt->open_fds->fds_bits[j++]; |
1da177e4 LT |
493 | while (set) { |
494 | if (set & 1) { | |
badf1662 | 495 | struct file * file = xchg(&fdt->fd[i], NULL); |
944be0b2 | 496 | if (file) { |
1da177e4 | 497 | filp_close(file, files); |
944be0b2 IM |
498 | cond_resched(); |
499 | } | |
1da177e4 LT |
500 | } |
501 | i++; | |
502 | set >>= 1; | |
503 | } | |
504 | } | |
505 | } | |
506 | ||
507 | struct files_struct *get_files_struct(struct task_struct *task) | |
508 | { | |
509 | struct files_struct *files; | |
510 | ||
511 | task_lock(task); | |
512 | files = task->files; | |
513 | if (files) | |
514 | atomic_inc(&files->count); | |
515 | task_unlock(task); | |
516 | ||
517 | return files; | |
518 | } | |
519 | ||
7ad5b3a5 | 520 | void put_files_struct(struct files_struct *files) |
1da177e4 | 521 | { |
badf1662 DS |
522 | struct fdtable *fdt; |
523 | ||
1da177e4 LT |
524 | if (atomic_dec_and_test(&files->count)) { |
525 | close_files(files); | |
526 | /* | |
527 | * Free the fd and fdset arrays if we expanded them. | |
ab2af1f5 DS |
528 | * If the fdtable was embedded, pass files for freeing |
529 | * at the end of the RCU grace period. Otherwise, | |
530 | * you can free files immediately. | |
1da177e4 | 531 | */ |
badf1662 | 532 | fdt = files_fdtable(files); |
4fd45812 | 533 | if (fdt != &files->fdtab) |
ab2af1f5 | 534 | kmem_cache_free(files_cachep, files); |
01b2d93c | 535 | free_fdtable(fdt); |
1da177e4 LT |
536 | } |
537 | } | |
538 | ||
3b125388 | 539 | void reset_files_struct(struct files_struct *files) |
3b9b8ab6 | 540 | { |
3b125388 | 541 | struct task_struct *tsk = current; |
3b9b8ab6 KK |
542 | struct files_struct *old; |
543 | ||
544 | old = tsk->files; | |
545 | task_lock(tsk); | |
546 | tsk->files = files; | |
547 | task_unlock(tsk); | |
548 | put_files_struct(old); | |
549 | } | |
3b9b8ab6 | 550 | |
1ec7f1dd | 551 | void exit_files(struct task_struct *tsk) |
1da177e4 LT |
552 | { |
553 | struct files_struct * files = tsk->files; | |
554 | ||
555 | if (files) { | |
556 | task_lock(tsk); | |
557 | tsk->files = NULL; | |
558 | task_unlock(tsk); | |
559 | put_files_struct(files); | |
560 | } | |
561 | } | |
562 | ||
1ec7f1dd | 563 | void put_fs_struct(struct fs_struct *fs) |
1da177e4 LT |
564 | { |
565 | /* No need to hold fs->lock if we are killing it */ | |
566 | if (atomic_dec_and_test(&fs->count)) { | |
6ac08c39 JB |
567 | path_put(&fs->root); |
568 | path_put(&fs->pwd); | |
1da177e4 LT |
569 | kmem_cache_free(fs_cachep, fs); |
570 | } | |
571 | } | |
572 | ||
1ec7f1dd | 573 | void exit_fs(struct task_struct *tsk) |
1da177e4 LT |
574 | { |
575 | struct fs_struct * fs = tsk->fs; | |
576 | ||
577 | if (fs) { | |
578 | task_lock(tsk); | |
579 | tsk->fs = NULL; | |
580 | task_unlock(tsk); | |
1ec7f1dd | 581 | put_fs_struct(fs); |
1da177e4 LT |
582 | } |
583 | } | |
584 | ||
1da177e4 LT |
585 | EXPORT_SYMBOL_GPL(exit_fs); |
586 | ||
cf475ad2 BS |
587 | #ifdef CONFIG_MM_OWNER |
588 | /* | |
589 | * Task p is exiting and it owned mm, lets find a new owner for it | |
590 | */ | |
591 | static inline int | |
592 | mm_need_new_owner(struct mm_struct *mm, struct task_struct *p) | |
593 | { | |
594 | /* | |
595 | * If there are other users of the mm and the owner (us) is exiting | |
596 | * we need to find a new owner to take on the responsibility. | |
597 | */ | |
cf475ad2 BS |
598 | if (atomic_read(&mm->mm_users) <= 1) |
599 | return 0; | |
600 | if (mm->owner != p) | |
601 | return 0; | |
602 | return 1; | |
603 | } | |
604 | ||
605 | void mm_update_next_owner(struct mm_struct *mm) | |
606 | { | |
607 | struct task_struct *c, *g, *p = current; | |
608 | ||
609 | retry: | |
610 | if (!mm_need_new_owner(mm, p)) | |
611 | return; | |
612 | ||
613 | read_lock(&tasklist_lock); | |
614 | /* | |
615 | * Search in the children | |
616 | */ | |
617 | list_for_each_entry(c, &p->children, sibling) { | |
618 | if (c->mm == mm) | |
619 | goto assign_new_owner; | |
620 | } | |
621 | ||
622 | /* | |
623 | * Search in the siblings | |
624 | */ | |
625 | list_for_each_entry(c, &p->parent->children, sibling) { | |
626 | if (c->mm == mm) | |
627 | goto assign_new_owner; | |
628 | } | |
629 | ||
630 | /* | |
631 | * Search through everything else. We should not get | |
632 | * here often | |
633 | */ | |
634 | do_each_thread(g, c) { | |
635 | if (c->mm == mm) | |
636 | goto assign_new_owner; | |
637 | } while_each_thread(g, c); | |
638 | ||
639 | read_unlock(&tasklist_lock); | |
31a78f23 BS |
640 | /* |
641 | * We found no owner yet mm_users > 1: this implies that we are | |
642 | * most likely racing with swapoff (try_to_unuse()) or /proc or | |
e5991371 | 643 | * ptrace or page migration (get_task_mm()). Mark owner as NULL. |
31a78f23 | 644 | */ |
31a78f23 | 645 | mm->owner = NULL; |
cf475ad2 BS |
646 | return; |
647 | ||
648 | assign_new_owner: | |
649 | BUG_ON(c == p); | |
650 | get_task_struct(c); | |
651 | /* | |
652 | * The task_lock protects c->mm from changing. | |
653 | * We always want mm->owner->mm == mm | |
654 | */ | |
655 | task_lock(c); | |
e5991371 HD |
656 | /* |
657 | * Delay read_unlock() till we have the task_lock() | |
658 | * to ensure that c does not slip away underneath us | |
659 | */ | |
660 | read_unlock(&tasklist_lock); | |
cf475ad2 BS |
661 | if (c->mm != mm) { |
662 | task_unlock(c); | |
663 | put_task_struct(c); | |
664 | goto retry; | |
665 | } | |
cf475ad2 BS |
666 | mm->owner = c; |
667 | task_unlock(c); | |
668 | put_task_struct(c); | |
669 | } | |
670 | #endif /* CONFIG_MM_OWNER */ | |
671 | ||
1da177e4 LT |
672 | /* |
673 | * Turn us into a lazy TLB process if we | |
674 | * aren't already.. | |
675 | */ | |
408b664a | 676 | static void exit_mm(struct task_struct * tsk) |
1da177e4 LT |
677 | { |
678 | struct mm_struct *mm = tsk->mm; | |
b564daf8 | 679 | struct core_state *core_state; |
1da177e4 LT |
680 | |
681 | mm_release(tsk, mm); | |
682 | if (!mm) | |
683 | return; | |
684 | /* | |
685 | * Serialize with any possible pending coredump. | |
999d9fc1 | 686 | * We must hold mmap_sem around checking core_state |
1da177e4 | 687 | * and clearing tsk->mm. The core-inducing thread |
999d9fc1 | 688 | * will increment ->nr_threads for each thread in the |
1da177e4 LT |
689 | * group with ->mm != NULL. |
690 | */ | |
691 | down_read(&mm->mmap_sem); | |
b564daf8 ON |
692 | core_state = mm->core_state; |
693 | if (core_state) { | |
694 | struct core_thread self; | |
1da177e4 | 695 | up_read(&mm->mmap_sem); |
1da177e4 | 696 | |
b564daf8 ON |
697 | self.task = tsk; |
698 | self.next = xchg(&core_state->dumper.next, &self); | |
699 | /* | |
700 | * Implies mb(), the result of xchg() must be visible | |
701 | * to core_state->dumper. | |
702 | */ | |
703 | if (atomic_dec_and_test(&core_state->nr_threads)) | |
704 | complete(&core_state->startup); | |
1da177e4 | 705 | |
a94e2d40 ON |
706 | for (;;) { |
707 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); | |
708 | if (!self.task) /* see coredump_finish() */ | |
709 | break; | |
710 | schedule(); | |
711 | } | |
712 | __set_task_state(tsk, TASK_RUNNING); | |
1da177e4 LT |
713 | down_read(&mm->mmap_sem); |
714 | } | |
715 | atomic_inc(&mm->mm_count); | |
125e1874 | 716 | BUG_ON(mm != tsk->active_mm); |
1da177e4 LT |
717 | /* more a memory barrier than a real lock */ |
718 | task_lock(tsk); | |
719 | tsk->mm = NULL; | |
720 | up_read(&mm->mmap_sem); | |
721 | enter_lazy_tlb(mm, current); | |
0c1eecfb RW |
722 | /* We don't want this task to be frozen prematurely */ |
723 | clear_freeze_flag(tsk); | |
1da177e4 | 724 | task_unlock(tsk); |
cf475ad2 | 725 | mm_update_next_owner(mm); |
1da177e4 LT |
726 | mmput(mm); |
727 | } | |
728 | ||
1da177e4 LT |
729 | /* |
730 | * When we die, we re-parent all our children. | |
731 | * Try to give them to another thread in our thread | |
732 | * group, and if no such member exists, give it to | |
84d73786 SB |
733 | * the child reaper process (ie "init") in our pid |
734 | * space. | |
1da177e4 | 735 | */ |
950bbabb | 736 | static struct task_struct *find_new_reaper(struct task_struct *father) |
1da177e4 | 737 | { |
950bbabb ON |
738 | struct pid_namespace *pid_ns = task_active_pid_ns(father); |
739 | struct task_struct *thread; | |
1da177e4 | 740 | |
950bbabb ON |
741 | thread = father; |
742 | while_each_thread(father, thread) { | |
743 | if (thread->flags & PF_EXITING) | |
744 | continue; | |
745 | if (unlikely(pid_ns->child_reaper == father)) | |
746 | pid_ns->child_reaper = thread; | |
747 | return thread; | |
748 | } | |
1da177e4 | 749 | |
950bbabb ON |
750 | if (unlikely(pid_ns->child_reaper == father)) { |
751 | write_unlock_irq(&tasklist_lock); | |
752 | if (unlikely(pid_ns == &init_pid_ns)) | |
753 | panic("Attempted to kill init!"); | |
1da177e4 | 754 | |
950bbabb ON |
755 | zap_pid_ns_processes(pid_ns); |
756 | write_lock_irq(&tasklist_lock); | |
1da177e4 | 757 | /* |
950bbabb ON |
758 | * We can not clear ->child_reaper or leave it alone. |
759 | * There may by stealth EXIT_DEAD tasks on ->children, | |
760 | * forget_original_parent() must move them somewhere. | |
1da177e4 | 761 | */ |
950bbabb | 762 | pid_ns->child_reaper = init_pid_ns.child_reaper; |
1da177e4 | 763 | } |
762a24be | 764 | |
950bbabb ON |
765 | return pid_ns->child_reaper; |
766 | } | |
767 | ||
5dfc80be ON |
768 | /* |
769 | * Any that need to be release_task'd are put on the @dead list. | |
770 | */ | |
771 | static void reparent_thread(struct task_struct *father, struct task_struct *p, | |
772 | struct list_head *dead) | |
773 | { | |
774 | if (p->pdeath_signal) | |
775 | group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p); | |
776 | ||
777 | list_move_tail(&p->sibling, &p->real_parent->children); | |
778 | ||
779 | if (task_detached(p)) | |
780 | return; | |
781 | /* | |
782 | * If this is a threaded reparent there is no need to | |
783 | * notify anyone anything has happened. | |
784 | */ | |
785 | if (same_thread_group(p->real_parent, father)) | |
786 | return; | |
787 | ||
788 | /* We don't want people slaying init. */ | |
789 | p->exit_signal = SIGCHLD; | |
790 | ||
791 | /* If it has exited notify the new parent about this child's death. */ | |
792 | if (!p->ptrace && | |
793 | p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) { | |
794 | do_notify_parent(p, p->exit_signal); | |
795 | if (task_detached(p)) { | |
796 | p->exit_state = EXIT_DEAD; | |
797 | list_move_tail(&p->sibling, dead); | |
798 | } | |
799 | } | |
800 | ||
801 | kill_orphaned_pgrp(p, father); | |
802 | } | |
803 | ||
762a24be | 804 | static void forget_original_parent(struct task_struct *father) |
1da177e4 | 805 | { |
950bbabb | 806 | struct task_struct *p, *n, *reaper; |
5dfc80be | 807 | LIST_HEAD(dead_children); |
762a24be | 808 | |
39c626ae ON |
809 | exit_ptrace(father); |
810 | ||
762a24be | 811 | write_lock_irq(&tasklist_lock); |
950bbabb | 812 | reaper = find_new_reaper(father); |
f470021a | 813 | |
03ff1797 | 814 | list_for_each_entry_safe(p, n, &father->children, sibling) { |
84eb646b | 815 | p->real_parent = reaper; |
f470021a RM |
816 | if (p->parent == father) { |
817 | BUG_ON(p->ptrace); | |
818 | p->parent = p->real_parent; | |
819 | } | |
5dfc80be | 820 | reparent_thread(father, p, &dead_children); |
1da177e4 | 821 | } |
762a24be | 822 | write_unlock_irq(&tasklist_lock); |
5dfc80be | 823 | |
762a24be | 824 | BUG_ON(!list_empty(&father->children)); |
762a24be | 825 | |
5dfc80be ON |
826 | list_for_each_entry_safe(p, n, &dead_children, sibling) { |
827 | list_del_init(&p->sibling); | |
39c626ae ON |
828 | release_task(p); |
829 | } | |
1da177e4 LT |
830 | } |
831 | ||
832 | /* | |
833 | * Send signals to all our closest relatives so that they know | |
834 | * to properly mourn us.. | |
835 | */ | |
821c7de7 | 836 | static void exit_notify(struct task_struct *tsk, int group_dead) |
1da177e4 | 837 | { |
2b2a1ff6 RM |
838 | int signal; |
839 | void *cookie; | |
1da177e4 | 840 | |
1da177e4 LT |
841 | /* |
842 | * This does two things: | |
843 | * | |
844 | * A. Make init inherit all the child processes | |
845 | * B. Check to see if any process groups have become orphaned | |
846 | * as a result of our exiting, and if they have any stopped | |
847 | * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) | |
848 | */ | |
762a24be | 849 | forget_original_parent(tsk); |
2e4a7072 | 850 | exit_task_namespaces(tsk); |
1da177e4 | 851 | |
762a24be | 852 | write_lock_irq(&tasklist_lock); |
821c7de7 ON |
853 | if (group_dead) |
854 | kill_orphaned_pgrp(tsk->group_leader, NULL); | |
1da177e4 | 855 | |
24728448 | 856 | /* Let father know we died |
1da177e4 LT |
857 | * |
858 | * Thread signals are configurable, but you aren't going to use | |
d4c5e41f | 859 | * that to send signals to arbitary processes. |
1da177e4 LT |
860 | * That stops right now. |
861 | * | |
862 | * If the parent exec id doesn't match the exec id we saved | |
863 | * when we started then we know the parent has changed security | |
864 | * domain. | |
865 | * | |
866 | * If our self_exec id doesn't match our parent_exec_id then | |
867 | * we have changed execution domain as these two values started | |
868 | * the same after a fork. | |
1da177e4 | 869 | */ |
d839fd4d | 870 | if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) && |
f49ee505 | 871 | (tsk->parent_exec_id != tsk->real_parent->self_exec_id || |
d839fd4d ON |
872 | tsk->self_exec_id != tsk->parent_exec_id) && |
873 | !capable(CAP_KILL)) | |
1da177e4 LT |
874 | tsk->exit_signal = SIGCHLD; |
875 | ||
2b2a1ff6 | 876 | signal = tracehook_notify_death(tsk, &cookie, group_dead); |
5c7edcd7 | 877 | if (signal >= 0) |
2b2a1ff6 | 878 | signal = do_notify_parent(tsk, signal); |
1da177e4 | 879 | |
5c7edcd7 | 880 | tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE; |
1da177e4 | 881 | |
2800d8d1 | 882 | /* mt-exec, de_thread() is waiting for us */ |
6db840fa | 883 | if (thread_group_leader(tsk) && |
2633f0e5 SV |
884 | tsk->signal->group_exit_task && |
885 | tsk->signal->notify_count < 0) | |
6db840fa ON |
886 | wake_up_process(tsk->signal->group_exit_task); |
887 | ||
1da177e4 LT |
888 | write_unlock_irq(&tasklist_lock); |
889 | ||
2b2a1ff6 RM |
890 | tracehook_report_death(tsk, signal, cookie, group_dead); |
891 | ||
1da177e4 | 892 | /* If the process is dead, release it - nobody will wait for it */ |
5c7edcd7 | 893 | if (signal == DEATH_REAP) |
1da177e4 | 894 | release_task(tsk); |
1da177e4 LT |
895 | } |
896 | ||
e18eecb8 JD |
897 | #ifdef CONFIG_DEBUG_STACK_USAGE |
898 | static void check_stack_usage(void) | |
899 | { | |
900 | static DEFINE_SPINLOCK(low_water_lock); | |
901 | static int lowest_to_date = THREAD_SIZE; | |
e18eecb8 JD |
902 | unsigned long free; |
903 | ||
7c9f8861 | 904 | free = stack_not_used(current); |
e18eecb8 JD |
905 | |
906 | if (free >= lowest_to_date) | |
907 | return; | |
908 | ||
909 | spin_lock(&low_water_lock); | |
910 | if (free < lowest_to_date) { | |
911 | printk(KERN_WARNING "%s used greatest stack depth: %lu bytes " | |
912 | "left\n", | |
913 | current->comm, free); | |
914 | lowest_to_date = free; | |
915 | } | |
916 | spin_unlock(&low_water_lock); | |
917 | } | |
918 | #else | |
919 | static inline void check_stack_usage(void) {} | |
920 | #endif | |
921 | ||
7ad5b3a5 | 922 | NORET_TYPE void do_exit(long code) |
1da177e4 LT |
923 | { |
924 | struct task_struct *tsk = current; | |
925 | int group_dead; | |
926 | ||
927 | profile_task_exit(tsk); | |
928 | ||
22e2c507 JA |
929 | WARN_ON(atomic_read(&tsk->fs_excl)); |
930 | ||
1da177e4 LT |
931 | if (unlikely(in_interrupt())) |
932 | panic("Aiee, killing interrupt handler!"); | |
933 | if (unlikely(!tsk->pid)) | |
934 | panic("Attempted to kill the idle task!"); | |
1da177e4 | 935 | |
30199f5a | 936 | tracehook_report_exit(&code); |
1da177e4 | 937 | |
df164db5 AN |
938 | /* |
939 | * We're taking recursive faults here in do_exit. Safest is to just | |
940 | * leave this task alone and wait for reboot. | |
941 | */ | |
942 | if (unlikely(tsk->flags & PF_EXITING)) { | |
943 | printk(KERN_ALERT | |
944 | "Fixing recursive fault but reboot is needed!\n"); | |
778e9a9c AK |
945 | /* |
946 | * We can do this unlocked here. The futex code uses | |
947 | * this flag just to verify whether the pi state | |
948 | * cleanup has been done or not. In the worst case it | |
949 | * loops once more. We pretend that the cleanup was | |
950 | * done as there is no way to return. Either the | |
951 | * OWNER_DIED bit is set by now or we push the blocked | |
952 | * task into the wait for ever nirwana as well. | |
953 | */ | |
954 | tsk->flags |= PF_EXITPIDONE; | |
df164db5 AN |
955 | set_current_state(TASK_UNINTERRUPTIBLE); |
956 | schedule(); | |
957 | } | |
958 | ||
d12619b5 | 959 | exit_signals(tsk); /* sets PF_EXITING */ |
778e9a9c AK |
960 | /* |
961 | * tsk->flags are checked in the futex code to protect against | |
962 | * an exiting task cleaning up the robust pi futexes. | |
963 | */ | |
d2ee7198 ON |
964 | smp_mb(); |
965 | spin_unlock_wait(&tsk->pi_lock); | |
1da177e4 | 966 | |
1da177e4 LT |
967 | if (unlikely(in_atomic())) |
968 | printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", | |
ba25f9dc | 969 | current->comm, task_pid_nr(current), |
1da177e4 LT |
970 | preempt_count()); |
971 | ||
972 | acct_update_integrals(tsk); | |
901608d9 | 973 | |
1da177e4 | 974 | group_dead = atomic_dec_and_test(&tsk->signal->live); |
c3068951 | 975 | if (group_dead) { |
778e9a9c | 976 | hrtimer_cancel(&tsk->signal->real_timer); |
25f407f0 | 977 | exit_itimers(tsk->signal); |
c3068951 | 978 | } |
f6ec29a4 | 979 | acct_collect(code, group_dead); |
522ed776 MT |
980 | if (group_dead) |
981 | tty_audit_exit(); | |
fa84cb93 AV |
982 | if (unlikely(tsk->audit_context)) |
983 | audit_free(tsk); | |
115085ea | 984 | |
f2ab6d88 | 985 | tsk->exit_code = code; |
115085ea | 986 | taskstats_exit(tsk, group_dead); |
c757249a | 987 | |
1da177e4 LT |
988 | exit_mm(tsk); |
989 | ||
0e464814 | 990 | if (group_dead) |
f6ec29a4 | 991 | acct_process(); |
0a16b607 MD |
992 | trace_sched_process_exit(tsk); |
993 | ||
1da177e4 | 994 | exit_sem(tsk); |
1ec7f1dd AV |
995 | exit_files(tsk); |
996 | exit_fs(tsk); | |
e18eecb8 | 997 | check_stack_usage(); |
1da177e4 | 998 | exit_thread(); |
b4f48b63 | 999 | cgroup_exit(tsk, 1); |
1da177e4 LT |
1000 | |
1001 | if (group_dead && tsk->signal->leader) | |
1002 | disassociate_ctty(1); | |
1003 | ||
a1261f54 | 1004 | module_put(task_thread_info(tsk)->exec_domain->module); |
1da177e4 LT |
1005 | if (tsk->binfmt) |
1006 | module_put(tsk->binfmt->module); | |
1007 | ||
9f46080c | 1008 | proc_exit_connector(tsk); |
821c7de7 | 1009 | exit_notify(tsk, group_dead); |
1da177e4 | 1010 | #ifdef CONFIG_NUMA |
f0be3d32 | 1011 | mpol_put(tsk->mempolicy); |
1da177e4 LT |
1012 | tsk->mempolicy = NULL; |
1013 | #endif | |
42b2dd0a | 1014 | #ifdef CONFIG_FUTEX |
c87e2837 IM |
1015 | /* |
1016 | * This must happen late, after the PID is not | |
1017 | * hashed anymore: | |
1018 | */ | |
1019 | if (unlikely(!list_empty(&tsk->pi_state_list))) | |
1020 | exit_pi_state_list(tsk); | |
1021 | if (unlikely(current->pi_state_cache)) | |
1022 | kfree(current->pi_state_cache); | |
42b2dd0a | 1023 | #endif |
de5097c2 | 1024 | /* |
9a11b49a | 1025 | * Make sure we are holding no locks: |
de5097c2 | 1026 | */ |
9a11b49a | 1027 | debug_check_no_locks_held(tsk); |
778e9a9c AK |
1028 | /* |
1029 | * We can do this unlocked here. The futex code uses this flag | |
1030 | * just to verify whether the pi state cleanup has been done | |
1031 | * or not. In the worst case it loops once more. | |
1032 | */ | |
1033 | tsk->flags |= PF_EXITPIDONE; | |
1da177e4 | 1034 | |
afc847b7 AV |
1035 | if (tsk->io_context) |
1036 | exit_io_context(); | |
1037 | ||
b92ce558 JA |
1038 | if (tsk->splice_pipe) |
1039 | __free_pipe_info(tsk->splice_pipe); | |
1040 | ||
7407251a | 1041 | preempt_disable(); |
55a101f8 | 1042 | /* causes final put_task_struct in finish_task_switch(). */ |
c394cc9f | 1043 | tsk->state = TASK_DEAD; |
1da177e4 LT |
1044 | schedule(); |
1045 | BUG(); | |
1046 | /* Avoid "noreturn function does return". */ | |
54306cf0 AC |
1047 | for (;;) |
1048 | cpu_relax(); /* For when BUG is null */ | |
1da177e4 LT |
1049 | } |
1050 | ||
012914da RA |
1051 | EXPORT_SYMBOL_GPL(do_exit); |
1052 | ||
1da177e4 LT |
1053 | NORET_TYPE void complete_and_exit(struct completion *comp, long code) |
1054 | { | |
1055 | if (comp) | |
1056 | complete(comp); | |
55a101f8 | 1057 | |
1da177e4 LT |
1058 | do_exit(code); |
1059 | } | |
1060 | ||
1061 | EXPORT_SYMBOL(complete_and_exit); | |
1062 | ||
754fe8d2 | 1063 | SYSCALL_DEFINE1(exit, int, error_code) |
1da177e4 LT |
1064 | { |
1065 | do_exit((error_code&0xff)<<8); | |
1066 | } | |
1067 | ||
1da177e4 LT |
1068 | /* |
1069 | * Take down every thread in the group. This is called by fatal signals | |
1070 | * as well as by sys_exit_group (below). | |
1071 | */ | |
1072 | NORET_TYPE void | |
1073 | do_group_exit(int exit_code) | |
1074 | { | |
bfc4b089 ON |
1075 | struct signal_struct *sig = current->signal; |
1076 | ||
1da177e4 LT |
1077 | BUG_ON(exit_code & 0x80); /* core dumps don't get here */ |
1078 | ||
bfc4b089 ON |
1079 | if (signal_group_exit(sig)) |
1080 | exit_code = sig->group_exit_code; | |
1da177e4 | 1081 | else if (!thread_group_empty(current)) { |
1da177e4 | 1082 | struct sighand_struct *const sighand = current->sighand; |
1da177e4 | 1083 | spin_lock_irq(&sighand->siglock); |
ed5d2cac | 1084 | if (signal_group_exit(sig)) |
1da177e4 LT |
1085 | /* Another thread got here before we took the lock. */ |
1086 | exit_code = sig->group_exit_code; | |
1087 | else { | |
1da177e4 | 1088 | sig->group_exit_code = exit_code; |
ed5d2cac | 1089 | sig->flags = SIGNAL_GROUP_EXIT; |
1da177e4 LT |
1090 | zap_other_threads(current); |
1091 | } | |
1092 | spin_unlock_irq(&sighand->siglock); | |
1da177e4 LT |
1093 | } |
1094 | ||
1095 | do_exit(exit_code); | |
1096 | /* NOTREACHED */ | |
1097 | } | |
1098 | ||
1099 | /* | |
1100 | * this kills every thread in the thread group. Note that any externally | |
1101 | * wait4()-ing process will get the correct exit code - even if this | |
1102 | * thread is not the thread group leader. | |
1103 | */ | |
754fe8d2 | 1104 | SYSCALL_DEFINE1(exit_group, int, error_code) |
1da177e4 LT |
1105 | { |
1106 | do_group_exit((error_code & 0xff) << 8); | |
2ed7c03e HC |
1107 | /* NOTREACHED */ |
1108 | return 0; | |
1da177e4 LT |
1109 | } |
1110 | ||
161550d7 EB |
1111 | static struct pid *task_pid_type(struct task_struct *task, enum pid_type type) |
1112 | { | |
1113 | struct pid *pid = NULL; | |
1114 | if (type == PIDTYPE_PID) | |
1115 | pid = task->pids[type].pid; | |
1116 | else if (type < PIDTYPE_MAX) | |
1117 | pid = task->group_leader->pids[type].pid; | |
1118 | return pid; | |
1119 | } | |
1120 | ||
1121 | static int eligible_child(enum pid_type type, struct pid *pid, int options, | |
1122 | struct task_struct *p) | |
1da177e4 | 1123 | { |
73243284 RM |
1124 | int err; |
1125 | ||
161550d7 EB |
1126 | if (type < PIDTYPE_MAX) { |
1127 | if (task_pid_type(p, type) != pid) | |
1da177e4 LT |
1128 | return 0; |
1129 | } | |
1130 | ||
1da177e4 LT |
1131 | /* Wait for all children (clone and not) if __WALL is set; |
1132 | * otherwise, wait for clone children *only* if __WCLONE is | |
1133 | * set; otherwise, wait for non-clone children *only*. (Note: | |
1134 | * A "clone" child here is one that reports to its parent | |
1135 | * using a signal other than SIGCHLD.) */ | |
1136 | if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0)) | |
1137 | && !(options & __WALL)) | |
1138 | return 0; | |
1da177e4 | 1139 | |
73243284 | 1140 | err = security_task_wait(p); |
14dd0b81 RM |
1141 | if (err) |
1142 | return err; | |
1da177e4 | 1143 | |
14dd0b81 | 1144 | return 1; |
1da177e4 LT |
1145 | } |
1146 | ||
36c8b586 | 1147 | static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid, |
1da177e4 LT |
1148 | int why, int status, |
1149 | struct siginfo __user *infop, | |
1150 | struct rusage __user *rusagep) | |
1151 | { | |
1152 | int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0; | |
36c8b586 | 1153 | |
1da177e4 LT |
1154 | put_task_struct(p); |
1155 | if (!retval) | |
1156 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1157 | if (!retval) | |
1158 | retval = put_user(0, &infop->si_errno); | |
1159 | if (!retval) | |
1160 | retval = put_user((short)why, &infop->si_code); | |
1161 | if (!retval) | |
1162 | retval = put_user(pid, &infop->si_pid); | |
1163 | if (!retval) | |
1164 | retval = put_user(uid, &infop->si_uid); | |
1165 | if (!retval) | |
1166 | retval = put_user(status, &infop->si_status); | |
1167 | if (!retval) | |
1168 | retval = pid; | |
1169 | return retval; | |
1170 | } | |
1171 | ||
1172 | /* | |
1173 | * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold | |
1174 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1175 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1176 | * released the lock and the system call should return. | |
1177 | */ | |
98abed02 | 1178 | static int wait_task_zombie(struct task_struct *p, int options, |
1da177e4 LT |
1179 | struct siginfo __user *infop, |
1180 | int __user *stat_addr, struct rusage __user *ru) | |
1181 | { | |
1182 | unsigned long state; | |
2f4e6e2a | 1183 | int retval, status, traced; |
6c5f3e7b | 1184 | pid_t pid = task_pid_vnr(p); |
c69e8d9c | 1185 | uid_t uid = __task_cred(p)->uid; |
1da177e4 | 1186 | |
98abed02 RM |
1187 | if (!likely(options & WEXITED)) |
1188 | return 0; | |
1189 | ||
1190 | if (unlikely(options & WNOWAIT)) { | |
1da177e4 LT |
1191 | int exit_code = p->exit_code; |
1192 | int why, status; | |
1193 | ||
1da177e4 LT |
1194 | get_task_struct(p); |
1195 | read_unlock(&tasklist_lock); | |
1196 | if ((exit_code & 0x7f) == 0) { | |
1197 | why = CLD_EXITED; | |
1198 | status = exit_code >> 8; | |
1199 | } else { | |
1200 | why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED; | |
1201 | status = exit_code & 0x7f; | |
1202 | } | |
1203 | return wait_noreap_copyout(p, pid, uid, why, | |
1204 | status, infop, ru); | |
1205 | } | |
1206 | ||
1207 | /* | |
1208 | * Try to move the task's state to DEAD | |
1209 | * only one thread is allowed to do this: | |
1210 | */ | |
1211 | state = xchg(&p->exit_state, EXIT_DEAD); | |
1212 | if (state != EXIT_ZOMBIE) { | |
1213 | BUG_ON(state != EXIT_DEAD); | |
1214 | return 0; | |
1215 | } | |
1da177e4 | 1216 | |
53b6f9fb | 1217 | traced = ptrace_reparented(p); |
2f4e6e2a ON |
1218 | |
1219 | if (likely(!traced)) { | |
3795e161 JJ |
1220 | struct signal_struct *psig; |
1221 | struct signal_struct *sig; | |
f06febc9 | 1222 | struct task_cputime cputime; |
3795e161 | 1223 | |
1da177e4 LT |
1224 | /* |
1225 | * The resource counters for the group leader are in its | |
1226 | * own task_struct. Those for dead threads in the group | |
1227 | * are in its signal_struct, as are those for the child | |
1228 | * processes it has previously reaped. All these | |
1229 | * accumulate in the parent's signal_struct c* fields. | |
1230 | * | |
1231 | * We don't bother to take a lock here to protect these | |
1232 | * p->signal fields, because they are only touched by | |
1233 | * __exit_signal, which runs with tasklist_lock | |
1234 | * write-locked anyway, and so is excluded here. We do | |
1235 | * need to protect the access to p->parent->signal fields, | |
1236 | * as other threads in the parent group can be right | |
1237 | * here reaping other children at the same time. | |
f06febc9 FM |
1238 | * |
1239 | * We use thread_group_cputime() to get times for the thread | |
1240 | * group, which consolidates times for all threads in the | |
1241 | * group including the group leader. | |
1da177e4 | 1242 | */ |
2b5fe6de | 1243 | thread_group_cputime(p, &cputime); |
1da177e4 | 1244 | spin_lock_irq(&p->parent->sighand->siglock); |
3795e161 JJ |
1245 | psig = p->parent->signal; |
1246 | sig = p->signal; | |
1247 | psig->cutime = | |
1248 | cputime_add(psig->cutime, | |
f06febc9 FM |
1249 | cputime_add(cputime.utime, |
1250 | sig->cutime)); | |
3795e161 JJ |
1251 | psig->cstime = |
1252 | cputime_add(psig->cstime, | |
f06febc9 FM |
1253 | cputime_add(cputime.stime, |
1254 | sig->cstime)); | |
9ac52315 LV |
1255 | psig->cgtime = |
1256 | cputime_add(psig->cgtime, | |
1257 | cputime_add(p->gtime, | |
1258 | cputime_add(sig->gtime, | |
1259 | sig->cgtime))); | |
3795e161 JJ |
1260 | psig->cmin_flt += |
1261 | p->min_flt + sig->min_flt + sig->cmin_flt; | |
1262 | psig->cmaj_flt += | |
1263 | p->maj_flt + sig->maj_flt + sig->cmaj_flt; | |
1264 | psig->cnvcsw += | |
1265 | p->nvcsw + sig->nvcsw + sig->cnvcsw; | |
1266 | psig->cnivcsw += | |
1267 | p->nivcsw + sig->nivcsw + sig->cnivcsw; | |
6eaeeaba ED |
1268 | psig->cinblock += |
1269 | task_io_get_inblock(p) + | |
1270 | sig->inblock + sig->cinblock; | |
1271 | psig->coublock += | |
1272 | task_io_get_oublock(p) + | |
1273 | sig->oublock + sig->coublock; | |
5995477a AR |
1274 | task_io_accounting_add(&psig->ioac, &p->ioac); |
1275 | task_io_accounting_add(&psig->ioac, &sig->ioac); | |
1da177e4 LT |
1276 | spin_unlock_irq(&p->parent->sighand->siglock); |
1277 | } | |
1278 | ||
1279 | /* | |
1280 | * Now we are sure this task is interesting, and no other | |
1281 | * thread can reap it because we set its state to EXIT_DEAD. | |
1282 | */ | |
1283 | read_unlock(&tasklist_lock); | |
1284 | ||
1285 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; | |
1286 | status = (p->signal->flags & SIGNAL_GROUP_EXIT) | |
1287 | ? p->signal->group_exit_code : p->exit_code; | |
1288 | if (!retval && stat_addr) | |
1289 | retval = put_user(status, stat_addr); | |
1290 | if (!retval && infop) | |
1291 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1292 | if (!retval && infop) | |
1293 | retval = put_user(0, &infop->si_errno); | |
1294 | if (!retval && infop) { | |
1295 | int why; | |
1296 | ||
1297 | if ((status & 0x7f) == 0) { | |
1298 | why = CLD_EXITED; | |
1299 | status >>= 8; | |
1300 | } else { | |
1301 | why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED; | |
1302 | status &= 0x7f; | |
1303 | } | |
1304 | retval = put_user((short)why, &infop->si_code); | |
1305 | if (!retval) | |
1306 | retval = put_user(status, &infop->si_status); | |
1307 | } | |
1308 | if (!retval && infop) | |
3a515e4a | 1309 | retval = put_user(pid, &infop->si_pid); |
1da177e4 | 1310 | if (!retval && infop) |
c69e8d9c | 1311 | retval = put_user(uid, &infop->si_uid); |
2f4e6e2a | 1312 | if (!retval) |
3a515e4a | 1313 | retval = pid; |
2f4e6e2a ON |
1314 | |
1315 | if (traced) { | |
1da177e4 | 1316 | write_lock_irq(&tasklist_lock); |
2f4e6e2a ON |
1317 | /* We dropped tasklist, ptracer could die and untrace */ |
1318 | ptrace_unlink(p); | |
1319 | /* | |
1320 | * If this is not a detached task, notify the parent. | |
1321 | * If it's still not detached after that, don't release | |
1322 | * it now. | |
1323 | */ | |
d839fd4d | 1324 | if (!task_detached(p)) { |
2f4e6e2a | 1325 | do_notify_parent(p, p->exit_signal); |
d839fd4d | 1326 | if (!task_detached(p)) { |
2f4e6e2a ON |
1327 | p->exit_state = EXIT_ZOMBIE; |
1328 | p = NULL; | |
1da177e4 LT |
1329 | } |
1330 | } | |
1331 | write_unlock_irq(&tasklist_lock); | |
1332 | } | |
1333 | if (p != NULL) | |
1334 | release_task(p); | |
2f4e6e2a | 1335 | |
1da177e4 LT |
1336 | return retval; |
1337 | } | |
1338 | ||
90bc8d8b ON |
1339 | static int *task_stopped_code(struct task_struct *p, bool ptrace) |
1340 | { | |
1341 | if (ptrace) { | |
1342 | if (task_is_stopped_or_traced(p)) | |
1343 | return &p->exit_code; | |
1344 | } else { | |
1345 | if (p->signal->flags & SIGNAL_STOP_STOPPED) | |
1346 | return &p->signal->group_exit_code; | |
1347 | } | |
1348 | return NULL; | |
1349 | } | |
1350 | ||
1da177e4 LT |
1351 | /* |
1352 | * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold | |
1353 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1354 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1355 | * released the lock and the system call should return. | |
1356 | */ | |
f470021a | 1357 | static int wait_task_stopped(int ptrace, struct task_struct *p, |
98abed02 | 1358 | int options, struct siginfo __user *infop, |
1da177e4 LT |
1359 | int __user *stat_addr, struct rusage __user *ru) |
1360 | { | |
90bc8d8b | 1361 | int retval, exit_code, *p_code, why; |
ee7c82da | 1362 | uid_t uid = 0; /* unneeded, required by compiler */ |
c8950783 | 1363 | pid_t pid; |
1da177e4 | 1364 | |
f470021a | 1365 | if (!(options & WUNTRACED)) |
98abed02 RM |
1366 | return 0; |
1367 | ||
ee7c82da ON |
1368 | exit_code = 0; |
1369 | spin_lock_irq(&p->sighand->siglock); | |
1370 | ||
90bc8d8b ON |
1371 | p_code = task_stopped_code(p, ptrace); |
1372 | if (unlikely(!p_code)) | |
ee7c82da ON |
1373 | goto unlock_sig; |
1374 | ||
90bc8d8b | 1375 | exit_code = *p_code; |
ee7c82da ON |
1376 | if (!exit_code) |
1377 | goto unlock_sig; | |
1378 | ||
98abed02 | 1379 | if (!unlikely(options & WNOWAIT)) |
90bc8d8b | 1380 | *p_code = 0; |
ee7c82da | 1381 | |
c69e8d9c DH |
1382 | /* don't need the RCU readlock here as we're holding a spinlock */ |
1383 | uid = __task_cred(p)->uid; | |
ee7c82da ON |
1384 | unlock_sig: |
1385 | spin_unlock_irq(&p->sighand->siglock); | |
1386 | if (!exit_code) | |
1da177e4 LT |
1387 | return 0; |
1388 | ||
1389 | /* | |
1390 | * Now we are pretty sure this task is interesting. | |
1391 | * Make sure it doesn't get reaped out from under us while we | |
1392 | * give up the lock and then examine it below. We don't want to | |
1393 | * keep holding onto the tasklist_lock while we call getrusage and | |
1394 | * possibly take page faults for user memory. | |
1395 | */ | |
1396 | get_task_struct(p); | |
6c5f3e7b | 1397 | pid = task_pid_vnr(p); |
f470021a | 1398 | why = ptrace ? CLD_TRAPPED : CLD_STOPPED; |
1da177e4 LT |
1399 | read_unlock(&tasklist_lock); |
1400 | ||
98abed02 | 1401 | if (unlikely(options & WNOWAIT)) |
1da177e4 | 1402 | return wait_noreap_copyout(p, pid, uid, |
e6ceb32a | 1403 | why, exit_code, |
1da177e4 | 1404 | infop, ru); |
1da177e4 LT |
1405 | |
1406 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; | |
1407 | if (!retval && stat_addr) | |
1408 | retval = put_user((exit_code << 8) | 0x7f, stat_addr); | |
1409 | if (!retval && infop) | |
1410 | retval = put_user(SIGCHLD, &infop->si_signo); | |
1411 | if (!retval && infop) | |
1412 | retval = put_user(0, &infop->si_errno); | |
1413 | if (!retval && infop) | |
6efcae46 | 1414 | retval = put_user((short)why, &infop->si_code); |
1da177e4 LT |
1415 | if (!retval && infop) |
1416 | retval = put_user(exit_code, &infop->si_status); | |
1417 | if (!retval && infop) | |
c8950783 | 1418 | retval = put_user(pid, &infop->si_pid); |
1da177e4 | 1419 | if (!retval && infop) |
ee7c82da | 1420 | retval = put_user(uid, &infop->si_uid); |
1da177e4 | 1421 | if (!retval) |
c8950783 | 1422 | retval = pid; |
1da177e4 LT |
1423 | put_task_struct(p); |
1424 | ||
1425 | BUG_ON(!retval); | |
1426 | return retval; | |
1427 | } | |
1428 | ||
1429 | /* | |
1430 | * Handle do_wait work for one task in a live, non-stopped state. | |
1431 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1432 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1433 | * released the lock and the system call should return. | |
1434 | */ | |
98abed02 | 1435 | static int wait_task_continued(struct task_struct *p, int options, |
1da177e4 LT |
1436 | struct siginfo __user *infop, |
1437 | int __user *stat_addr, struct rusage __user *ru) | |
1438 | { | |
1439 | int retval; | |
1440 | pid_t pid; | |
1441 | uid_t uid; | |
1442 | ||
98abed02 RM |
1443 | if (!unlikely(options & WCONTINUED)) |
1444 | return 0; | |
1445 | ||
1da177e4 LT |
1446 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) |
1447 | return 0; | |
1448 | ||
1449 | spin_lock_irq(&p->sighand->siglock); | |
1450 | /* Re-check with the lock held. */ | |
1451 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) { | |
1452 | spin_unlock_irq(&p->sighand->siglock); | |
1453 | return 0; | |
1454 | } | |
98abed02 | 1455 | if (!unlikely(options & WNOWAIT)) |
1da177e4 | 1456 | p->signal->flags &= ~SIGNAL_STOP_CONTINUED; |
c69e8d9c | 1457 | uid = __task_cred(p)->uid; |
1da177e4 LT |
1458 | spin_unlock_irq(&p->sighand->siglock); |
1459 | ||
6c5f3e7b | 1460 | pid = task_pid_vnr(p); |
1da177e4 LT |
1461 | get_task_struct(p); |
1462 | read_unlock(&tasklist_lock); | |
1463 | ||
1464 | if (!infop) { | |
1465 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; | |
1466 | put_task_struct(p); | |
1467 | if (!retval && stat_addr) | |
1468 | retval = put_user(0xffff, stat_addr); | |
1469 | if (!retval) | |
3a515e4a | 1470 | retval = pid; |
1da177e4 LT |
1471 | } else { |
1472 | retval = wait_noreap_copyout(p, pid, uid, | |
1473 | CLD_CONTINUED, SIGCONT, | |
1474 | infop, ru); | |
1475 | BUG_ON(retval == 0); | |
1476 | } | |
1477 | ||
1478 | return retval; | |
1479 | } | |
1480 | ||
98abed02 RM |
1481 | /* |
1482 | * Consider @p for a wait by @parent. | |
1483 | * | |
1484 | * -ECHILD should be in *@notask_error before the first call. | |
1485 | * Returns nonzero for a final return, when we have unlocked tasklist_lock. | |
1486 | * Returns zero if the search for a child should continue; | |
14dd0b81 RM |
1487 | * then *@notask_error is 0 if @p is an eligible child, |
1488 | * or another error from security_task_wait(), or still -ECHILD. | |
98abed02 | 1489 | */ |
f470021a | 1490 | static int wait_consider_task(struct task_struct *parent, int ptrace, |
98abed02 RM |
1491 | struct task_struct *p, int *notask_error, |
1492 | enum pid_type type, struct pid *pid, int options, | |
1493 | struct siginfo __user *infop, | |
1494 | int __user *stat_addr, struct rusage __user *ru) | |
1495 | { | |
1496 | int ret = eligible_child(type, pid, options, p); | |
14dd0b81 | 1497 | if (!ret) |
98abed02 RM |
1498 | return ret; |
1499 | ||
14dd0b81 RM |
1500 | if (unlikely(ret < 0)) { |
1501 | /* | |
1502 | * If we have not yet seen any eligible child, | |
1503 | * then let this error code replace -ECHILD. | |
1504 | * A permission error will give the user a clue | |
1505 | * to look for security policy problems, rather | |
1506 | * than for mysterious wait bugs. | |
1507 | */ | |
1508 | if (*notask_error) | |
1509 | *notask_error = ret; | |
1510 | } | |
1511 | ||
f470021a RM |
1512 | if (likely(!ptrace) && unlikely(p->ptrace)) { |
1513 | /* | |
1514 | * This child is hidden by ptrace. | |
1515 | * We aren't allowed to see it now, but eventually we will. | |
1516 | */ | |
1517 | *notask_error = 0; | |
1518 | return 0; | |
1519 | } | |
1520 | ||
98abed02 RM |
1521 | if (p->exit_state == EXIT_DEAD) |
1522 | return 0; | |
1523 | ||
1524 | /* | |
1525 | * We don't reap group leaders with subthreads. | |
1526 | */ | |
1527 | if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p)) | |
1528 | return wait_task_zombie(p, options, infop, stat_addr, ru); | |
1529 | ||
1530 | /* | |
1531 | * It's stopped or running now, so it might | |
1532 | * later continue, exit, or stop again. | |
1533 | */ | |
1534 | *notask_error = 0; | |
1535 | ||
90bc8d8b | 1536 | if (task_stopped_code(p, ptrace)) |
f470021a RM |
1537 | return wait_task_stopped(ptrace, p, options, |
1538 | infop, stat_addr, ru); | |
98abed02 RM |
1539 | |
1540 | return wait_task_continued(p, options, infop, stat_addr, ru); | |
1541 | } | |
1542 | ||
1543 | /* | |
1544 | * Do the work of do_wait() for one thread in the group, @tsk. | |
1545 | * | |
1546 | * -ECHILD should be in *@notask_error before the first call. | |
1547 | * Returns nonzero for a final return, when we have unlocked tasklist_lock. | |
1548 | * Returns zero if the search for a child should continue; then | |
14dd0b81 RM |
1549 | * *@notask_error is 0 if there were any eligible children, |
1550 | * or another error from security_task_wait(), or still -ECHILD. | |
98abed02 RM |
1551 | */ |
1552 | static int do_wait_thread(struct task_struct *tsk, int *notask_error, | |
1553 | enum pid_type type, struct pid *pid, int options, | |
1554 | struct siginfo __user *infop, int __user *stat_addr, | |
1555 | struct rusage __user *ru) | |
1556 | { | |
1557 | struct task_struct *p; | |
1558 | ||
1559 | list_for_each_entry(p, &tsk->children, sibling) { | |
f470021a RM |
1560 | /* |
1561 | * Do not consider detached threads. | |
1562 | */ | |
1563 | if (!task_detached(p)) { | |
1564 | int ret = wait_consider_task(tsk, 0, p, notask_error, | |
1565 | type, pid, options, | |
1566 | infop, stat_addr, ru); | |
1567 | if (ret) | |
1568 | return ret; | |
1569 | } | |
98abed02 RM |
1570 | } |
1571 | ||
1572 | return 0; | |
1573 | } | |
1574 | ||
1575 | static int ptrace_do_wait(struct task_struct *tsk, int *notask_error, | |
1576 | enum pid_type type, struct pid *pid, int options, | |
1577 | struct siginfo __user *infop, int __user *stat_addr, | |
1578 | struct rusage __user *ru) | |
1579 | { | |
1580 | struct task_struct *p; | |
1581 | ||
1582 | /* | |
f470021a | 1583 | * Traditionally we see ptrace'd stopped tasks regardless of options. |
98abed02 | 1584 | */ |
f470021a | 1585 | options |= WUNTRACED; |
98abed02 | 1586 | |
f470021a RM |
1587 | list_for_each_entry(p, &tsk->ptraced, ptrace_entry) { |
1588 | int ret = wait_consider_task(tsk, 1, p, notask_error, | |
1589 | type, pid, options, | |
1590 | infop, stat_addr, ru); | |
1591 | if (ret) | |
98abed02 | 1592 | return ret; |
98abed02 RM |
1593 | } |
1594 | ||
1595 | return 0; | |
1596 | } | |
1597 | ||
161550d7 EB |
1598 | static long do_wait(enum pid_type type, struct pid *pid, int options, |
1599 | struct siginfo __user *infop, int __user *stat_addr, | |
1600 | struct rusage __user *ru) | |
1da177e4 LT |
1601 | { |
1602 | DECLARE_WAITQUEUE(wait, current); | |
1603 | struct task_struct *tsk; | |
98abed02 | 1604 | int retval; |
1da177e4 | 1605 | |
0a16b607 MD |
1606 | trace_sched_process_wait(pid); |
1607 | ||
1da177e4 LT |
1608 | add_wait_queue(¤t->signal->wait_chldexit,&wait); |
1609 | repeat: | |
98abed02 RM |
1610 | /* |
1611 | * If there is nothing that can match our critiera just get out. | |
1612 | * We will clear @retval to zero if we see any child that might later | |
1613 | * match our criteria, even if we are not able to reap it yet. | |
1614 | */ | |
161550d7 EB |
1615 | retval = -ECHILD; |
1616 | if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type]))) | |
1617 | goto end; | |
1618 | ||
1da177e4 LT |
1619 | current->state = TASK_INTERRUPTIBLE; |
1620 | read_lock(&tasklist_lock); | |
1621 | tsk = current; | |
1622 | do { | |
98abed02 RM |
1623 | int tsk_result = do_wait_thread(tsk, &retval, |
1624 | type, pid, options, | |
1625 | infop, stat_addr, ru); | |
1626 | if (!tsk_result) | |
1627 | tsk_result = ptrace_do_wait(tsk, &retval, | |
1628 | type, pid, options, | |
1629 | infop, stat_addr, ru); | |
1630 | if (tsk_result) { | |
1631 | /* | |
1632 | * tasklist_lock is unlocked and we have a final result. | |
1633 | */ | |
1634 | retval = tsk_result; | |
1635 | goto end; | |
1da177e4 | 1636 | } |
98abed02 | 1637 | |
1da177e4 LT |
1638 | if (options & __WNOTHREAD) |
1639 | break; | |
1640 | tsk = next_thread(tsk); | |
125e1874 | 1641 | BUG_ON(tsk->signal != current->signal); |
1da177e4 | 1642 | } while (tsk != current); |
1da177e4 | 1643 | read_unlock(&tasklist_lock); |
f2cc3eb1 | 1644 | |
98abed02 | 1645 | if (!retval && !(options & WNOHANG)) { |
1da177e4 | 1646 | retval = -ERESTARTSYS; |
98abed02 RM |
1647 | if (!signal_pending(current)) { |
1648 | schedule(); | |
1649 | goto repeat; | |
1650 | } | |
1da177e4 | 1651 | } |
98abed02 | 1652 | |
1da177e4 LT |
1653 | end: |
1654 | current->state = TASK_RUNNING; | |
1655 | remove_wait_queue(¤t->signal->wait_chldexit,&wait); | |
1656 | if (infop) { | |
1657 | if (retval > 0) | |
9cbab810 | 1658 | retval = 0; |
1da177e4 LT |
1659 | else { |
1660 | /* | |
1661 | * For a WNOHANG return, clear out all the fields | |
1662 | * we would set so the user can easily tell the | |
1663 | * difference. | |
1664 | */ | |
1665 | if (!retval) | |
1666 | retval = put_user(0, &infop->si_signo); | |
1667 | if (!retval) | |
1668 | retval = put_user(0, &infop->si_errno); | |
1669 | if (!retval) | |
1670 | retval = put_user(0, &infop->si_code); | |
1671 | if (!retval) | |
1672 | retval = put_user(0, &infop->si_pid); | |
1673 | if (!retval) | |
1674 | retval = put_user(0, &infop->si_uid); | |
1675 | if (!retval) | |
1676 | retval = put_user(0, &infop->si_status); | |
1677 | } | |
1678 | } | |
1679 | return retval; | |
1680 | } | |
1681 | ||
17da2bd9 HC |
1682 | SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, |
1683 | infop, int, options, struct rusage __user *, ru) | |
1da177e4 | 1684 | { |
161550d7 EB |
1685 | struct pid *pid = NULL; |
1686 | enum pid_type type; | |
1da177e4 LT |
1687 | long ret; |
1688 | ||
1689 | if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED)) | |
1690 | return -EINVAL; | |
1691 | if (!(options & (WEXITED|WSTOPPED|WCONTINUED))) | |
1692 | return -EINVAL; | |
1693 | ||
1694 | switch (which) { | |
1695 | case P_ALL: | |
161550d7 | 1696 | type = PIDTYPE_MAX; |
1da177e4 LT |
1697 | break; |
1698 | case P_PID: | |
161550d7 EB |
1699 | type = PIDTYPE_PID; |
1700 | if (upid <= 0) | |
1da177e4 LT |
1701 | return -EINVAL; |
1702 | break; | |
1703 | case P_PGID: | |
161550d7 EB |
1704 | type = PIDTYPE_PGID; |
1705 | if (upid <= 0) | |
1da177e4 | 1706 | return -EINVAL; |
1da177e4 LT |
1707 | break; |
1708 | default: | |
1709 | return -EINVAL; | |
1710 | } | |
1711 | ||
161550d7 EB |
1712 | if (type < PIDTYPE_MAX) |
1713 | pid = find_get_pid(upid); | |
1714 | ret = do_wait(type, pid, options, infop, NULL, ru); | |
1715 | put_pid(pid); | |
1da177e4 LT |
1716 | |
1717 | /* avoid REGPARM breakage on x86: */ | |
54a01510 | 1718 | asmlinkage_protect(5, ret, which, upid, infop, options, ru); |
1da177e4 LT |
1719 | return ret; |
1720 | } | |
1721 | ||
754fe8d2 HC |
1722 | SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr, |
1723 | int, options, struct rusage __user *, ru) | |
1da177e4 | 1724 | { |
161550d7 EB |
1725 | struct pid *pid = NULL; |
1726 | enum pid_type type; | |
1da177e4 LT |
1727 | long ret; |
1728 | ||
1729 | if (options & ~(WNOHANG|WUNTRACED|WCONTINUED| | |
1730 | __WNOTHREAD|__WCLONE|__WALL)) | |
1731 | return -EINVAL; | |
161550d7 EB |
1732 | |
1733 | if (upid == -1) | |
1734 | type = PIDTYPE_MAX; | |
1735 | else if (upid < 0) { | |
1736 | type = PIDTYPE_PGID; | |
1737 | pid = find_get_pid(-upid); | |
1738 | } else if (upid == 0) { | |
1739 | type = PIDTYPE_PGID; | |
2ae448ef | 1740 | pid = get_task_pid(current, PIDTYPE_PGID); |
161550d7 EB |
1741 | } else /* upid > 0 */ { |
1742 | type = PIDTYPE_PID; | |
1743 | pid = find_get_pid(upid); | |
1744 | } | |
1745 | ||
1746 | ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru); | |
1747 | put_pid(pid); | |
1da177e4 LT |
1748 | |
1749 | /* avoid REGPARM breakage on x86: */ | |
54a01510 | 1750 | asmlinkage_protect(4, ret, upid, stat_addr, options, ru); |
1da177e4 LT |
1751 | return ret; |
1752 | } | |
1753 | ||
1754 | #ifdef __ARCH_WANT_SYS_WAITPID | |
1755 | ||
1756 | /* | |
1757 | * sys_waitpid() remains for compatibility. waitpid() should be | |
1758 | * implemented by calling sys_wait4() from libc.a. | |
1759 | */ | |
17da2bd9 | 1760 | SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options) |
1da177e4 LT |
1761 | { |
1762 | return sys_wait4(pid, stat_addr, options, NULL); | |
1763 | } | |
1764 | ||
1765 | #endif |