| 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/iocontext.h>
|
| 17 | #include <linux/key.h>
|
| 18 | #include <linux/security.h>
|
| 19 | #include <linux/cpu.h>
|
| 20 | #include <linux/acct.h>
|
| 21 | #include <linux/tsacct_kern.h>
|
| 22 | #include <linux/file.h>
|
| 23 | #include <linux/fdtable.h>
|
| 24 | #include <linux/binfmts.h>
|
| 25 | #include <linux/nsproxy.h>
|
| 26 | #include <linux/pid_namespace.h>
|
| 27 | #include <linux/ptrace.h>
|
| 28 | #include <linux/profile.h>
|
| 29 | #include <linux/mount.h>
|
| 30 | #include <linux/proc_fs.h>
|
| 31 | #include <linux/kthread.h>
|
| 32 | #include <linux/mempolicy.h>
|
| 33 | #include <linux/taskstats_kern.h>
|
| 34 | #include <linux/delayacct.h>
|
| 35 | #include <linux/freezer.h>
|
| 36 | #include <linux/cgroup.h>
|
| 37 | #include <linux/syscalls.h>
|
| 38 | #include <linux/signal.h>
|
| 39 | #include <linux/posix-timers.h>
|
| 40 | #include <linux/cn_proc.h>
|
| 41 | #include <linux/mutex.h>
|
| 42 | #include <linux/futex.h>
|
| 43 | #include <linux/pipe_fs_i.h>
|
| 44 | #include <linux/audit.h>
|
| 45 | #include <linux/resource.h>
|
| 46 | #include <linux/blkdev.h>
|
| 47 | #include <linux/task_io_accounting_ops.h>
|
| 48 | #include <linux/tracehook.h>
|
| 49 | #include <trace/sched.h>
|
| 50 |
|
| 51 | #include <asm/uaccess.h>
|
| 52 | #include <asm/unistd.h>
|
| 53 | #include <asm/pgtable.h>
|
| 54 | #include <asm/mmu_context.h>
|
| 55 |
|
| 56 | static void exit_mm(struct task_struct * tsk);
|
| 57 |
|
| 58 | static inline int task_detached(struct task_struct *p)
|
| 59 | {
|
| 60 | return p->exit_signal == -1;
|
| 61 | }
|
| 62 |
|
| 63 | static void __unhash_process(struct task_struct *p)
|
| 64 | {
|
| 65 | nr_threads--;
|
| 66 | detach_pid(p, PIDTYPE_PID);
|
| 67 | if (thread_group_leader(p)) {
|
| 68 | detach_pid(p, PIDTYPE_PGID);
|
| 69 | detach_pid(p, PIDTYPE_SID);
|
| 70 |
|
| 71 | list_del_rcu(&p->tasks);
|
| 72 | __get_cpu_var(process_counts)--;
|
| 73 | }
|
| 74 | list_del_rcu(&p->thread_group);
|
| 75 | list_del_init(&p->sibling);
|
| 76 | }
|
| 77 |
|
| 78 | |
| 79 | * This function expects the tasklist_lock write-locked.
|
| 80 |
|
| 81 | static void __exit_signal(struct task_struct *tsk)
|
| 82 | {
|
| 83 | struct signal_struct *sig = tsk->signal;
|
| 84 | struct sighand_struct *sighand;
|
| 85 |
|
| 86 | BUG_ON(!sig);
|
| 87 | BUG_ON(!atomic_read(&sig->count));
|
| 88 |
|
| 89 | sighand = rcu_dereference(tsk->sighand);
|
| 90 | spin_lock(&sighand->siglock);
|
| 91 |
|
| 92 | posix_cpu_timers_exit(tsk);
|
| 93 | if (atomic_dec_and_test(&sig->count))
|
| 94 | posix_cpu_timers_exit_group(tsk);
|
| 95 | else {
|
| 96 | |
| 97 | * If there is any task waiting for the group exit
|
| 98 | * then notify it:
|
| 99 |
|
| 100 | if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count)
|
| 101 | wake_up_process(sig->group_exit_task);
|
| 102 |
|
| 103 | if (tsk == sig->curr_target)
|
| 104 | sig->curr_target = next_thread(tsk);
|
| 105 | |
| 106 | * Accumulate here the counters for all threads but the
|
| 107 | * group leader as they die, so they can be added into
|
| 108 | * the process-wide totals when those are taken.
|
| 109 | * The group leader stays around as a zombie as long
|
| 110 | * as there are other threads. When it gets reaped,
|
| 111 | * the exit.c code will add its counts into these totals.
|
| 112 | * We won't ever get here for the group leader, since it
|
| 113 | * will have been the last reference on the signal_struct.
|
| 114 |
|
| 115 | sig->gtime = cputime_add(sig->gtime, task_gtime(tsk));
|
| 116 | sig->min_flt += tsk->min_flt;
|
| 117 | sig->maj_flt += tsk->maj_flt;
|
| 118 | sig->nvcsw += tsk->nvcsw;
|
| 119 | sig->nivcsw += tsk->nivcsw;
|
| 120 | sig->inblock += task_io_get_inblock(tsk);
|
| 121 | sig->oublock += task_io_get_oublock(tsk);
|
| 122 | task_io_accounting_add(&sig->ioac, &tsk->ioac);
|
| 123 | sig = NULL;
|
| 124 | }
|
| 125 |
|
| 126 | __unhash_process(tsk);
|
| 127 |
|
| 128 | |
| 129 | * Do this under ->siglock, we can race with another thread
|
| 130 | * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
|
| 131 |
|
| 132 | flush_sigqueue(&tsk->pending);
|
| 133 |
|
| 134 | tsk->signal = NULL;
|
| 135 | tsk->sighand = NULL;
|
| 136 | spin_unlock(&sighand->siglock);
|
| 137 |
|
| 138 | __cleanup_sighand(sighand);
|
| 139 | clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
|
| 140 | if (sig) {
|
| 141 | flush_sigqueue(&sig->shared_pending);
|
| 142 | taskstats_tgid_free(sig);
|
| 143 | |
| 144 | * Make sure ->signal can't go away under rq->lock,
|
| 145 | * see account_group_exec_runtime().
|
| 146 |
|
| 147 | task_rq_unlock_wait(tsk);
|
| 148 | __cleanup_signal(sig);
|
| 149 | }
|
| 150 | }
|
| 151 |
|
| 152 | static void delayed_put_task_struct(struct rcu_head *rhp)
|
| 153 | {
|
| 154 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
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| 155 |
|
| 156 | trace_sched_process_free(tsk);
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| 157 | put_task_struct(tsk);
|
| 158 | }
|
| 159 |
|
| 160 |
|
| 161 | void release_task(struct task_struct * p)
|
| 162 | {
|
| 163 | struct task_struct *leader;
|
| 164 | int zap_leader;
|
| 165 | repeat:
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| 166 | tracehook_prepare_release_task(p);
|
| 167 | atomic_dec(&p->user->processes);
|
| 168 | proc_flush_task(p);
|
| 169 | write_lock_irq(&tasklist_lock);
|
| 170 | tracehook_finish_release_task(p);
|
| 171 | __exit_signal(p);
|
| 172 |
|
| 173 | |
| 174 | * If we are the last non-leader member of the thread
|
| 175 | * group, and the leader is zombie, then notify the
|
| 176 | * group leader's parent process. (if it wants notification.)
|
| 177 |
|
| 178 | zap_leader = 0;
|
| 179 | leader = p->group_leader;
|
| 180 | if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
|
| 181 | BUG_ON(task_detached(leader));
|
| 182 | do_notify_parent(leader, leader->exit_signal);
|
| 183 | |
| 184 | * If we were the last child thread and the leader has
|
| 185 | * exited already, and the leader's parent ignores SIGCHLD,
|
| 186 | * then we are the one who should release the leader.
|
| 187 | *
|
| 188 | * do_notify_parent() will have marked it self-reaping in
|
| 189 | * that case.
|
| 190 |
|
| 191 | zap_leader = task_detached(leader);
|
| 192 |
|
| 193 | |
| 194 | * This maintains the invariant that release_task()
|
| 195 | * only runs on a task in EXIT_DEAD, just for sanity.
|
| 196 |
|
| 197 | if (zap_leader)
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| 198 | leader->exit_state = EXIT_DEAD;
|
| 199 | }
|
| 200 |
|
| 201 | write_unlock_irq(&tasklist_lock);
|
| 202 | release_thread(p);
|
| 203 | call_rcu(&p->rcu, delayed_put_task_struct);
|
| 204 |
|
| 205 | p = leader;
|
| 206 | if (unlikely(zap_leader))
|
| 207 | goto repeat;
|
| 208 | }
|
| 209 |
|
| 210 | |
| 211 | * This checks not only the pgrp, but falls back on the pid if no
|
| 212 | * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
|
| 213 | * without this...
|
| 214 | *
|
| 215 | * The caller must hold rcu lock or the tasklist lock.
|
| 216 |
|
| 217 | struct pid *session_of_pgrp(struct pid *pgrp)
|
| 218 | {
|
| 219 | struct task_struct *p;
|
| 220 | struct pid *sid = NULL;
|
| 221 |
|
| 222 | p = pid_task(pgrp, PIDTYPE_PGID);
|
| 223 | if (p == NULL)
|
| 224 | p = pid_task(pgrp, PIDTYPE_PID);
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| 225 | if (p != NULL)
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| 226 | sid = task_session(p);
|
| 227 |
|
| 228 | return sid;
|
| 229 | }
|
| 230 |
|
| 231 | |
| 232 | * Determine if a process group is "orphaned", according to the POSIX
|
| 233 | * definition in 2.2.2.52. Orphaned process groups are not to be affected
|
| 234 | * by terminal-generated stop signals. Newly orphaned process groups are
|
| 235 | * to receive a SIGHUP and a SIGCONT.
|
| 236 | *
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| 237 | * "I ask you, have you ever known what it is to be an orphan?"
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| 238 |
|
| 239 | static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task)
|
| 240 | {
|
| 241 | struct task_struct *p;
|
| 242 |
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| 243 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
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| 244 | if ((p == ignored_task) ||
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| 245 | (p->exit_state && thread_group_empty(p)) ||
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| 246 | is_global_init(p->real_parent))
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| 247 | continue;
|
| 248 |
|
| 249 | if (task_pgrp(p->real_parent) != pgrp &&
|
| 250 | task_session(p->real_parent) == task_session(p))
|
| 251 | return 0;
|
| 252 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
|
| 253 |
|
| 254 | return 1;
|
| 255 | }
|
| 256 |
|
| 257 | int is_current_pgrp_orphaned(void)
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| 258 | {
|
| 259 | int retval;
|
| 260 |
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| 261 | read_lock(&tasklist_lock);
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| 262 | retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
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| 263 | read_unlock(&tasklist_lock);
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| 264 |
|
| 265 | return retval;
|
| 266 | }
|
| 267 |
|
| 268 | static int has_stopped_jobs(struct pid *pgrp)
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| 269 | {
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| 270 | int retval = 0;
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| 271 | struct task_struct *p;
|
| 272 |
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| 273 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
|
| 274 | if (!task_is_stopped(p))
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| 275 | continue;
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| 276 | retval = 1;
|
| 277 | break;
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| 278 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
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| 279 | return retval;
|
| 280 | }
|
| 281 |
|
| 282 | |
| 283 | * Check to see if any process groups have become orphaned as
|
| 284 | * a result of our exiting, and if they have any stopped jobs,
|
| 285 | * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
|
| 286 |
|
| 287 | static void
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| 288 | kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
|
| 289 | {
|
| 290 | struct pid *pgrp = task_pgrp(tsk);
|
| 291 | struct task_struct *ignored_task = tsk;
|
| 292 |
|
| 293 | if (!parent)
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| 294 | |
| 295 | * we are and we were the only connection outside.
|
| 296 |
|
| 297 | parent = tsk->real_parent;
|
| 298 | else
|
| 299 | |
| 300 | * we are, and it was the only connection outside.
|
| 301 |
|
| 302 | ignored_task = NULL;
|
| 303 |
|
| 304 | if (task_pgrp(parent) != pgrp &&
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| 305 | task_session(parent) == task_session(tsk) &&
|
| 306 | will_become_orphaned_pgrp(pgrp, ignored_task) &&
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| 307 | has_stopped_jobs(pgrp)) {
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| 308 | __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
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| 309 | __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
|
| 310 | }
|
| 311 | }
|
| 312 |
|
| 313 | |
| 314 | * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
|
| 315 | *
|
| 316 | * If a kernel thread is launched as a result of a system call, or if
|
| 317 | * it ever exits, it should generally reparent itself to kthreadd so it
|
| 318 | * isn't in the way of other processes and is correctly cleaned up on exit.
|
| 319 | *
|
| 320 | * The various task state such as scheduling policy and priority may have
|
| 321 | * been inherited from a user process, so we reset them to sane values here.
|
| 322 | *
|
| 323 | * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
|
| 324 |
|
| 325 | static void reparent_to_kthreadd(void)
|
| 326 | {
|
| 327 | write_lock_irq(&tasklist_lock);
|
| 328 |
|
| 329 | ptrace_unlink(current);
|
| 330 |
|
| 331 | current->real_parent = current->parent = kthreadd_task;
|
| 332 | list_move_tail(¤t->sibling, ¤t->real_parent->children);
|
| 333 |
|
| 334 |
|
| 335 | current->exit_signal = SIGCHLD;
|
| 336 |
|
| 337 | if (task_nice(current) < 0)
|
| 338 | set_user_nice(current, 0);
|
| 339 |
|
| 340 |
|
| 341 |
|
| 342 | security_task_reparent_to_init(current);
|
| 343 | memcpy(current->signal->rlim, init_task.signal->rlim,
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| 344 | sizeof(current->signal->rlim));
|
| 345 | atomic_inc(&(INIT_USER->__count));
|
| 346 | write_unlock_irq(&tasklist_lock);
|
| 347 | switch_uid(INIT_USER);
|
| 348 | }
|
| 349 |
|
| 350 | void __set_special_pids(struct pid *pid)
|
| 351 | {
|
| 352 | struct task_struct *curr = current->group_leader;
|
| 353 | pid_t nr = pid_nr(pid);
|
| 354 |
|
| 355 | if (task_session(curr) != pid) {
|
| 356 | change_pid(curr, PIDTYPE_SID, pid);
|
| 357 | set_task_session(curr, nr);
|
| 358 | }
|
| 359 | if (task_pgrp(curr) != pid) {
|
| 360 | change_pid(curr, PIDTYPE_PGID, pid);
|
| 361 | set_task_pgrp(curr, nr);
|
| 362 | }
|
| 363 | }
|
| 364 |
|
| 365 | static void set_special_pids(struct pid *pid)
|
| 366 | {
|
| 367 | write_lock_irq(&tasklist_lock);
|
| 368 | __set_special_pids(pid);
|
| 369 | write_unlock_irq(&tasklist_lock);
|
| 370 | }
|
| 371 |
|
| 372 | |
| 373 | * Let kernel threads use this to say that they
|
| 374 | * allow a certain signal (since daemonize() will
|
| 375 | * have disabled all of them by default).
|
| 376 |
|
| 377 | int allow_signal(int sig)
|
| 378 | {
|
| 379 | if (!valid_signal(sig) || sig < 1)
|
| 380 | return -EINVAL;
|
| 381 |
|
| 382 | spin_lock_irq(¤t->sighand->siglock);
|
| 383 | sigdelset(¤t->blocked, sig);
|
| 384 | if (!current->mm) {
|
| 385 | |
| 386 | Let the signal code know it'll be handled, so
|
| 387 | that they don't get converted to SIGKILL or
|
| 388 | just silently dropped
|
| 389 | current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
|
| 390 | }
|
| 391 | recalc_sigpending();
|
| 392 | spin_unlock_irq(¤t->sighand->siglock);
|
| 393 | return 0;
|
| 394 | }
|
| 395 |
|
| 396 | EXPORT_SYMBOL(allow_signal);
|
| 397 |
|
| 398 | int disallow_signal(int sig)
|
| 399 | {
|
| 400 | if (!valid_signal(sig) || sig < 1)
|
| 401 | return -EINVAL;
|
| 402 |
|
| 403 | spin_lock_irq(¤t->sighand->siglock);
|
| 404 | current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
|
| 405 | recalc_sigpending();
|
| 406 | spin_unlock_irq(¤t->sighand->siglock);
|
| 407 | return 0;
|
| 408 | }
|
| 409 |
|
| 410 | EXPORT_SYMBOL(disallow_signal);
|
| 411 |
|
| 412 | |
| 413 | * Put all the gunge required to become a kernel thread without
|
| 414 | * attached user resources in one place where it belongs.
|
| 415 |
|
| 416 |
|
| 417 | void daemonize(const char *name, ...)
|
| 418 | {
|
| 419 | va_list args;
|
| 420 | struct fs_struct *fs;
|
| 421 | sigset_t blocked;
|
| 422 |
|
| 423 | va_start(args, name);
|
| 424 | vsnprintf(current->comm, sizeof(current->comm), name, args);
|
| 425 | va_end(args);
|
| 426 |
|
| 427 | |
| 428 | * If we were started as result of loading a module, close all of the
|
| 429 | * user space pages. We don't need them, and if we didn't close them
|
| 430 | * they would be locked into memory.
|
| 431 |
|
| 432 | exit_mm(current);
|
| 433 | |
| 434 | * We don't want to have TIF_FREEZE set if the system-wide hibernation
|
| 435 | * or suspend transition begins right now.
|
| 436 |
|
| 437 | current->flags |= (PF_NOFREEZE | PF_KTHREAD);
|
| 438 |
|
| 439 | if (current->nsproxy != &init_nsproxy) {
|
| 440 | get_nsproxy(&init_nsproxy);
|
| 441 | switch_task_namespaces(current, &init_nsproxy);
|
| 442 | }
|
| 443 | set_special_pids(&init_struct_pid);
|
| 444 | proc_clear_tty(current);
|
| 445 |
|
| 446 |
|
| 447 | sigfillset(&blocked);
|
| 448 | sigprocmask(SIG_BLOCK, &blocked, NULL);
|
| 449 | flush_signals(current);
|
| 450 |
|
| 451 |
|
| 452 |
|
| 453 | exit_fs(current);
|
| 454 | fs = init_task.fs;
|
| 455 | current->fs = fs;
|
| 456 | atomic_inc(&fs->count);
|
| 457 |
|
| 458 | exit_files(current);
|
| 459 | current->files = init_task.files;
|
| 460 | atomic_inc(¤t->files->count);
|
| 461 |
|
| 462 | reparent_to_kthreadd();
|
| 463 | }
|
| 464 |
|
| 465 | EXPORT_SYMBOL(daemonize);
|
| 466 |
|
| 467 | static void close_files(struct files_struct * files)
|
| 468 | {
|
| 469 | int i, j;
|
| 470 | struct fdtable *fdt;
|
| 471 |
|
| 472 | j = 0;
|
| 473 |
|
| 474 | |
| 475 | * It is safe to dereference the fd table without RCU or
|
| 476 | * ->file_lock because this is the last reference to the
|
| 477 | * files structure.
|
| 478 |
|
| 479 | fdt = files_fdtable(files);
|
| 480 | for (;;) {
|
| 481 | unsigned long set;
|
| 482 | i = j * __NFDBITS;
|
| 483 | if (i >= fdt->max_fds)
|
| 484 | break;
|
| 485 | set = fdt->open_fds->fds_bits[j++];
|
| 486 | while (set) {
|
| 487 | if (set & 1) {
|
| 488 | struct file * file = xchg(&fdt->fd[i], NULL);
|
| 489 | if (file) {
|
| 490 | filp_close(file, files);
|
| 491 | cond_resched();
|
| 492 | }
|
| 493 | }
|
| 494 | i++;
|
| 495 | set >>= 1;
|
| 496 | }
|
| 497 | }
|
| 498 | }
|
| 499 |
|
| 500 | struct files_struct *get_files_struct(struct task_struct *task)
|
| 501 | {
|
| 502 | struct files_struct *files;
|
| 503 |
|
| 504 | task_lock(task);
|
| 505 | files = task->files;
|
| 506 | if (files)
|
| 507 | atomic_inc(&files->count);
|
| 508 | task_unlock(task);
|
| 509 |
|
| 510 | return files;
|
| 511 | }
|
| 512 |
|
| 513 | void put_files_struct(struct files_struct *files)
|
| 514 | {
|
| 515 | struct fdtable *fdt;
|
| 516 |
|
| 517 | if (atomic_dec_and_test(&files->count)) {
|
| 518 | close_files(files);
|
| 519 | |
| 520 | * Free the fd and fdset arrays if we expanded them.
|
| 521 | * If the fdtable was embedded, pass files for freeing
|
| 522 | * at the end of the RCU grace period. Otherwise,
|
| 523 | * you can free files immediately.
|
| 524 |
|
| 525 | fdt = files_fdtable(files);
|
| 526 | if (fdt != &files->fdtab)
|
| 527 | kmem_cache_free(files_cachep, files);
|
| 528 | free_fdtable(fdt);
|
| 529 | }
|
| 530 | }
|
| 531 |
|
| 532 | void reset_files_struct(struct files_struct *files)
|
| 533 | {
|
| 534 | struct task_struct *tsk = current;
|
| 535 | struct files_struct *old;
|
| 536 |
|
| 537 | old = tsk->files;
|
| 538 | task_lock(tsk);
|
| 539 | tsk->files = files;
|
| 540 | task_unlock(tsk);
|
| 541 | put_files_struct(old);
|
| 542 | }
|
| 543 |
|
| 544 | void exit_files(struct task_struct *tsk)
|
| 545 | {
|
| 546 | struct files_struct * files = tsk->files;
|
| 547 |
|
| 548 | if (files) {
|
| 549 | task_lock(tsk);
|
| 550 | tsk->files = NULL;
|
| 551 | task_unlock(tsk);
|
| 552 | put_files_struct(files);
|
| 553 | }
|
| 554 | }
|
| 555 |
|
| 556 | void put_fs_struct(struct fs_struct *fs)
|
| 557 | {
|
| 558 |
|
| 559 | if (atomic_dec_and_test(&fs->count)) {
|
| 560 | path_put(&fs->root);
|
| 561 | path_put(&fs->pwd);
|
| 562 | kmem_cache_free(fs_cachep, fs);
|
| 563 | }
|
| 564 | }
|
| 565 |
|
| 566 | void exit_fs(struct task_struct *tsk)
|
| 567 | {
|
| 568 | struct fs_struct * fs = tsk->fs;
|
| 569 |
|
| 570 | if (fs) {
|
| 571 | task_lock(tsk);
|
| 572 | tsk->fs = NULL;
|
| 573 | task_unlock(tsk);
|
| 574 | put_fs_struct(fs);
|
| 575 | }
|
| 576 | }
|
| 577 |
|
| 578 | EXPORT_SYMBOL_GPL(exit_fs);
|
| 579 |
|
| 580 | #ifdef CONFIG_MM_OWNER
|
| 581 | |
| 582 | * Task p is exiting and it owned mm, lets find a new owner for it
|
| 583 |
|
| 584 | static inline int
|
| 585 | mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
|
| 586 | {
|
| 587 | |
| 588 | * If there are other users of the mm and the owner (us) is exiting
|
| 589 | * we need to find a new owner to take on the responsibility.
|
| 590 |
|
| 591 | if (atomic_read(&mm->mm_users) <= 1)
|
| 592 | return 0;
|
| 593 | if (mm->owner != p)
|
| 594 | return 0;
|
| 595 | return 1;
|
| 596 | }
|
| 597 |
|
| 598 | void mm_update_next_owner(struct mm_struct *mm)
|
| 599 | {
|
| 600 | struct task_struct *c, *g, *p = current;
|
| 601 |
|
| 602 | retry:
|
| 603 | if (!mm_need_new_owner(mm, p))
|
| 604 | return;
|
| 605 |
|
| 606 | read_lock(&tasklist_lock);
|
| 607 | |
| 608 | * Search in the children
|
| 609 |
|
| 610 | list_for_each_entry(c, &p->children, sibling) {
|
| 611 | if (c->mm == mm)
|
| 612 | goto assign_new_owner;
|
| 613 | }
|
| 614 |
|
| 615 | |
| 616 | * Search in the siblings
|
| 617 |
|
| 618 | list_for_each_entry(c, &p->parent->children, sibling) {
|
| 619 | if (c->mm == mm)
|
| 620 | goto assign_new_owner;
|
| 621 | }
|
| 622 |
|
| 623 | |
| 624 | * Search through everything else. We should not get
|
| 625 | * here often
|
| 626 |
|
| 627 | do_each_thread(g, c) {
|
| 628 | if (c->mm == mm)
|
| 629 | goto assign_new_owner;
|
| 630 | } while_each_thread(g, c);
|
| 631 |
|
| 632 | read_unlock(&tasklist_lock);
|
| 633 | |
| 634 | * We found no owner yet mm_users > 1: this implies that we are
|
| 635 | * most likely racing with swapoff (try_to_unuse()) or /proc or
|
| 636 | * ptrace or page migration (get_task_mm()). Mark owner as NULL,
|
| 637 | * so that subsystems can understand the callback and take action.
|
| 638 |
|
| 639 | down_write(&mm->mmap_sem);
|
| 640 | cgroup_mm_owner_callbacks(mm->owner, NULL);
|
| 641 | mm->owner = NULL;
|
| 642 | up_write(&mm->mmap_sem);
|
| 643 | return;
|
| 644 |
|
| 645 | assign_new_owner:
|
| 646 | BUG_ON(c == p);
|
| 647 | get_task_struct(c);
|
| 648 | read_unlock(&tasklist_lock);
|
| 649 | down_write(&mm->mmap_sem);
|
| 650 | |
| 651 | * The task_lock protects c->mm from changing.
|
| 652 | * We always want mm->owner->mm == mm
|
| 653 |
|
| 654 | task_lock(c);
|
| 655 | if (c->mm != mm) {
|
| 656 | task_unlock(c);
|
| 657 | up_write(&mm->mmap_sem);
|
| 658 | put_task_struct(c);
|
| 659 | goto retry;
|
| 660 | }
|
| 661 | cgroup_mm_owner_callbacks(mm->owner, c);
|
| 662 | mm->owner = c;
|
| 663 | task_unlock(c);
|
| 664 | up_write(&mm->mmap_sem);
|
| 665 | put_task_struct(c);
|
| 666 | }
|
| 667 | #endif
|
| 668 |
|
| 669 | |
| 670 | * Turn us into a lazy TLB process if we
|
| 671 | * aren't already..
|
| 672 |
|
| 673 | static void exit_mm(struct task_struct * tsk)
|
| 674 | {
|
| 675 | struct mm_struct *mm = tsk->mm;
|
| 676 | struct core_state *core_state;
|
| 677 |
|
| 678 | mm_release(tsk, mm);
|
| 679 | if (!mm)
|
| 680 | return;
|
| 681 | |
| 682 | * Serialize with any possible pending coredump.
|
| 683 | * We must hold mmap_sem around checking core_state
|
| 684 | * and clearing tsk->mm. The core-inducing thread
|
| 685 | * will increment ->nr_threads for each thread in the
|
| 686 | * group with ->mm != NULL.
|
| 687 |
|
| 688 | down_read(&mm->mmap_sem);
|
| 689 | core_state = mm->core_state;
|
| 690 | if (core_state) {
|
| 691 | struct core_thread self;
|
| 692 | up_read(&mm->mmap_sem);
|
| 693 |
|
| 694 | self.task = tsk;
|
| 695 | self.next = xchg(&core_state->dumper.next, &self);
|
| 696 | |
| 697 | * Implies mb(), the result of xchg() must be visible
|
| 698 | * to core_state->dumper.
|
| 699 |
|
| 700 | if (atomic_dec_and_test(&core_state->nr_threads))
|
| 701 | complete(&core_state->startup);
|
| 702 |
|
| 703 | for (;;) {
|
| 704 | set_task_state(tsk, TASK_UNINTERRUPTIBLE);
|
| 705 | if (!self.task)
|
| 706 | break;
|
| 707 | schedule();
|
| 708 | }
|
| 709 | __set_task_state(tsk, TASK_RUNNING);
|
| 710 | down_read(&mm->mmap_sem);
|
| 711 | }
|
| 712 | atomic_inc(&mm->mm_count);
|
| 713 | BUG_ON(mm != tsk->active_mm);
|
| 714 |
|
| 715 | task_lock(tsk);
|
| 716 | tsk->mm = NULL;
|
| 717 | up_read(&mm->mmap_sem);
|
| 718 | enter_lazy_tlb(mm, current);
|
| 719 |
|
| 720 | clear_freeze_flag(tsk);
|
| 721 | task_unlock(tsk);
|
| 722 | mm_update_next_owner(mm);
|
| 723 | mmput(mm);
|
| 724 | }
|
| 725 |
|
| 726 | |
| 727 | * Return nonzero if @parent's children should reap themselves.
|
| 728 | *
|
| 729 | * Called with write_lock_irq(&tasklist_lock) held.
|
| 730 |
|
| 731 | static int ignoring_children(struct task_struct *parent)
|
| 732 | {
|
| 733 | int ret;
|
| 734 | struct sighand_struct *psig = parent->sighand;
|
| 735 | unsigned long flags;
|
| 736 | spin_lock_irqsave(&psig->siglock, flags);
|
| 737 | ret = (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
|
| 738 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT));
|
| 739 | spin_unlock_irqrestore(&psig->siglock, flags);
|
| 740 | return ret;
|
| 741 | }
|
| 742 |
|
| 743 | |
| 744 | * Detach all tasks we were using ptrace on.
|
| 745 | * Any that need to be release_task'd are put on the @dead list.
|
| 746 | *
|
| 747 | * Called with write_lock(&tasklist_lock) held.
|
| 748 |
|
| 749 | static void ptrace_exit(struct task_struct *parent, struct list_head *dead)
|
| 750 | {
|
| 751 | struct task_struct *p, *n;
|
| 752 | int ign = -1;
|
| 753 |
|
| 754 | list_for_each_entry_safe(p, n, &parent->ptraced, ptrace_entry) {
|
| 755 | __ptrace_unlink(p);
|
| 756 |
|
| 757 | if (p->exit_state != EXIT_ZOMBIE)
|
| 758 | continue;
|
| 759 |
|
| 760 | |
| 761 | * If it's a zombie, our attachedness prevented normal
|
| 762 | * parent notification or self-reaping. Do notification
|
| 763 | * now if it would have happened earlier. If it should
|
| 764 | * reap itself, add it to the @dead list. We can't call
|
| 765 | * release_task() here because we already hold tasklist_lock.
|
| 766 | *
|
| 767 | * If it's our own child, there is no notification to do.
|
| 768 | * But if our normal children self-reap, then this child
|
| 769 | * was prevented by ptrace and we must reap it now.
|
| 770 |
|
| 771 | if (!task_detached(p) && thread_group_empty(p)) {
|
| 772 | if (!same_thread_group(p->real_parent, parent))
|
| 773 | do_notify_parent(p, p->exit_signal);
|
| 774 | else {
|
| 775 | if (ign < 0)
|
| 776 | ign = ignoring_children(parent);
|
| 777 | if (ign)
|
| 778 | p->exit_signal = -1;
|
| 779 | }
|
| 780 | }
|
| 781 |
|
| 782 | if (task_detached(p)) {
|
| 783 | |
| 784 | * Mark it as in the process of being reaped.
|
| 785 |
|
| 786 | p->exit_state = EXIT_DEAD;
|
| 787 | list_add(&p->ptrace_entry, dead);
|
| 788 | }
|
| 789 | }
|
| 790 | }
|
| 791 |
|
| 792 | |
| 793 | * Finish up exit-time ptrace cleanup.
|
| 794 | *
|
| 795 | * Called without locks.
|
| 796 |
|
| 797 | static void ptrace_exit_finish(struct task_struct *parent,
|
| 798 | struct list_head *dead)
|
| 799 | {
|
| 800 | struct task_struct *p, *n;
|
| 801 |
|
| 802 | BUG_ON(!list_empty(&parent->ptraced));
|
| 803 |
|
| 804 | list_for_each_entry_safe(p, n, dead, ptrace_entry) {
|
| 805 | list_del_init(&p->ptrace_entry);
|
| 806 | release_task(p);
|
| 807 | }
|
| 808 | }
|
| 809 |
|
| 810 | static void reparent_thread(struct task_struct *p, struct task_struct *father)
|
| 811 | {
|
| 812 | if (p->pdeath_signal)
|
| 813 |
|
| 814 | group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
|
| 815 |
|
| 816 | list_move_tail(&p->sibling, &p->real_parent->children);
|
| 817 |
|
| 818 | |
| 819 | * notify anyone anything has happened.
|
| 820 |
|
| 821 | if (same_thread_group(p->real_parent, father))
|
| 822 | return;
|
| 823 |
|
| 824 |
|
| 825 | if (!task_detached(p))
|
| 826 | p->exit_signal = SIGCHLD;
|
| 827 |
|
| 828 | |
| 829 | * also notify the new parent.
|
| 830 |
|
| 831 | if (!ptrace_reparented(p) &&
|
| 832 | p->exit_state == EXIT_ZOMBIE &&
|
| 833 | !task_detached(p) && thread_group_empty(p))
|
| 834 | do_notify_parent(p, p->exit_signal);
|
| 835 |
|
| 836 | kill_orphaned_pgrp(p, father);
|
| 837 | }
|
| 838 |
|
| 839 | |
| 840 | * When we die, we re-parent all our children.
|
| 841 | * Try to give them to another thread in our thread
|
| 842 | * group, and if no such member exists, give it to
|
| 843 | * the child reaper process (ie "init") in our pid
|
| 844 | * space.
|
| 845 |
|
| 846 | static struct task_struct *find_new_reaper(struct task_struct *father)
|
| 847 | {
|
| 848 | struct pid_namespace *pid_ns = task_active_pid_ns(father);
|
| 849 | struct task_struct *thread;
|
| 850 |
|
| 851 | thread = father;
|
| 852 | while_each_thread(father, thread) {
|
| 853 | if (thread->flags & PF_EXITING)
|
| 854 | continue;
|
| 855 | if (unlikely(pid_ns->child_reaper == father))
|
| 856 | pid_ns->child_reaper = thread;
|
| 857 | return thread;
|
| 858 | }
|
| 859 |
|
| 860 | if (unlikely(pid_ns->child_reaper == father)) {
|
| 861 | write_unlock_irq(&tasklist_lock);
|
| 862 | if (unlikely(pid_ns == &init_pid_ns))
|
| 863 | panic("Attempted to kill init!");
|
| 864 |
|
| 865 | zap_pid_ns_processes(pid_ns);
|
| 866 | write_lock_irq(&tasklist_lock);
|
| 867 | |
| 868 | * We can not clear ->child_reaper or leave it alone.
|
| 869 | * There may by stealth EXIT_DEAD tasks on ->children,
|
| 870 | * forget_original_parent() must move them somewhere.
|
| 871 |
|
| 872 | pid_ns->child_reaper = init_pid_ns.child_reaper;
|
| 873 | }
|
| 874 |
|
| 875 | return pid_ns->child_reaper;
|
| 876 | }
|
| 877 |
|
| 878 | static void forget_original_parent(struct task_struct *father)
|
| 879 | {
|
| 880 | struct task_struct *p, *n, *reaper;
|
| 881 | LIST_HEAD(ptrace_dead);
|
| 882 |
|
| 883 | write_lock_irq(&tasklist_lock);
|
| 884 | reaper = find_new_reaper(father);
|
| 885 | |
| 886 | * First clean up ptrace if we were using it.
|
| 887 |
|
| 888 | ptrace_exit(father, &ptrace_dead);
|
| 889 |
|
| 890 | list_for_each_entry_safe(p, n, &father->children, sibling) {
|
| 891 | p->real_parent = reaper;
|
| 892 | if (p->parent == father) {
|
| 893 | BUG_ON(p->ptrace);
|
| 894 | p->parent = p->real_parent;
|
| 895 | }
|
| 896 | reparent_thread(p, father);
|
| 897 | }
|
| 898 |
|
| 899 | write_unlock_irq(&tasklist_lock);
|
| 900 | BUG_ON(!list_empty(&father->children));
|
| 901 |
|
| 902 | ptrace_exit_finish(father, &ptrace_dead);
|
| 903 | }
|
| 904 |
|
| 905 | |
| 906 | * Send signals to all our closest relatives so that they know
|
| 907 | * to properly mourn us..
|
| 908 |
|
| 909 | static void exit_notify(struct task_struct *tsk, int group_dead)
|
| 910 | {
|
| 911 | int signal;
|
| 912 | void *cookie;
|
| 913 |
|
| 914 | |
| 915 | * This does two things:
|
| 916 | *
|
| 917 | * A. Make init inherit all the child processes
|
| 918 | * B. Check to see if any process groups have become orphaned
|
| 919 | * as a result of our exiting, and if they have any stopped
|
| 920 | * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
|
| 921 |
|
| 922 | forget_original_parent(tsk);
|
| 923 | exit_task_namespaces(tsk);
|
| 924 |
|
| 925 | write_lock_irq(&tasklist_lock);
|
| 926 | if (group_dead)
|
| 927 | kill_orphaned_pgrp(tsk->group_leader, NULL);
|
| 928 |
|
| 929 | |
| 930 | *
|
| 931 | * Thread signals are configurable, but you aren't going to use
|
| 932 | * that to send signals to arbitary processes.
|
| 933 | * That stops right now.
|
| 934 | *
|
| 935 | * If the parent exec id doesn't match the exec id we saved
|
| 936 | * when we started then we know the parent has changed security
|
| 937 | * domain.
|
| 938 | *
|
| 939 | * If our self_exec id doesn't match our parent_exec_id then
|
| 940 | * we have changed execution domain as these two values started
|
| 941 | * the same after a fork.
|
| 942 |
|
| 943 | if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) &&
|
| 944 | (tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
|
| 945 | tsk->self_exec_id != tsk->parent_exec_id) &&
|
| 946 | !capable(CAP_KILL))
|
| 947 | tsk->exit_signal = SIGCHLD;
|
| 948 |
|
| 949 | signal = tracehook_notify_death(tsk, &cookie, group_dead);
|
| 950 | if (signal >= 0)
|
| 951 | signal = do_notify_parent(tsk, signal);
|
| 952 |
|
| 953 | tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE;
|
| 954 |
|
| 955 |
|
| 956 | if (thread_group_leader(tsk) &&
|
| 957 | tsk->signal->group_exit_task &&
|
| 958 | tsk->signal->notify_count < 0)
|
| 959 | wake_up_process(tsk->signal->group_exit_task);
|
| 960 |
|
| 961 | write_unlock_irq(&tasklist_lock);
|
| 962 |
|
| 963 | tracehook_report_death(tsk, signal, cookie, group_dead);
|
| 964 |
|
| 965 |
|
| 966 | if (signal == DEATH_REAP)
|
| 967 | release_task(tsk);
|
| 968 | }
|
| 969 |
|
| 970 | #ifdef CONFIG_DEBUG_STACK_USAGE
|
| 971 | static void check_stack_usage(void)
|
| 972 | {
|
| 973 | static DEFINE_SPINLOCK(low_water_lock);
|
| 974 | static int lowest_to_date = THREAD_SIZE;
|
| 975 | unsigned long *n = end_of_stack(current);
|
| 976 | unsigned long free;
|
| 977 |
|
| 978 | while (*n == 0)
|
| 979 | n++;
|
| 980 | free = (unsigned long)n - (unsigned long)end_of_stack(current);
|
| 981 |
|
| 982 | if (free >= lowest_to_date)
|
| 983 | return;
|
| 984 |
|
| 985 | spin_lock(&low_water_lock);
|
| 986 | if (free < lowest_to_date) {
|
| 987 | printk(KERN_WARNING "%s used greatest stack depth: %lu bytes "
|
| 988 | "left\n",
|
| 989 | current->comm, free);
|
| 990 | lowest_to_date = free;
|
| 991 | }
|
| 992 | spin_unlock(&low_water_lock);
|
| 993 | }
|
| 994 | #else
|
| 995 | static inline void check_stack_usage(void) {}
|
| 996 | #endif
|
| 997 |
|
| 998 | NORET_TYPE void do_exit(long code)
|
| 999 | {
|
| 1000 | struct task_struct *tsk = current;
|
| 1001 | int group_dead;
|
| 1002 |
|
| 1003 | profile_task_exit(tsk);
|
| 1004 |
|
| 1005 | WARN_ON(atomic_read(&tsk->fs_excl));
|
| 1006 |
|
| 1007 | if (unlikely(in_interrupt()))
|
| 1008 | panic("Aiee, killing interrupt handler!");
|
| 1009 | if (unlikely(!tsk->pid))
|
| 1010 | panic("Attempted to kill the idle task!");
|
| 1011 |
|
| 1012 | tracehook_report_exit(&code);
|
| 1013 |
|
| 1014 | |
| 1015 | * We're taking recursive faults here in do_exit. Safest is to just
|
| 1016 | * leave this task alone and wait for reboot.
|
| 1017 |
|
| 1018 | if (unlikely(tsk->flags & PF_EXITING)) {
|
| 1019 | printk(KERN_ALERT
|
| 1020 | "Fixing recursive fault but reboot is needed!\n");
|
| 1021 | |
| 1022 | * We can do this unlocked here. The futex code uses
|
| 1023 | * this flag just to verify whether the pi state
|
| 1024 | * cleanup has been done or not. In the worst case it
|
| 1025 | * loops once more. We pretend that the cleanup was
|
| 1026 | * done as there is no way to return. Either the
|
| 1027 | * OWNER_DIED bit is set by now or we push the blocked
|
| 1028 | * task into the wait for ever nirwana as well.
|
| 1029 |
|
| 1030 | tsk->flags |= PF_EXITPIDONE;
|
| 1031 | if (tsk->io_context)
|
| 1032 | exit_io_context();
|
| 1033 | set_current_state(TASK_UNINTERRUPTIBLE);
|
| 1034 | schedule();
|
| 1035 | }
|
| 1036 |
|
| 1037 | exit_signals(tsk);
|
| 1038 | |
| 1039 | * tsk->flags are checked in the futex code to protect against
|
| 1040 | * an exiting task cleaning up the robust pi futexes.
|
| 1041 |
|
| 1042 | smp_mb();
|
| 1043 | spin_unlock_wait(&tsk->pi_lock);
|
| 1044 |
|
| 1045 | if (unlikely(in_atomic()))
|
| 1046 | printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
|
| 1047 | current->comm, task_pid_nr(current),
|
| 1048 | preempt_count());
|
| 1049 |
|
| 1050 | acct_update_integrals(tsk);
|
| 1051 | if (tsk->mm) {
|
| 1052 | update_hiwater_rss(tsk->mm);
|
| 1053 | update_hiwater_vm(tsk->mm);
|
| 1054 | }
|
| 1055 | group_dead = atomic_dec_and_test(&tsk->signal->live);
|
| 1056 | if (group_dead) {
|
| 1057 | hrtimer_cancel(&tsk->signal->real_timer);
|
| 1058 | exit_itimers(tsk->signal);
|
| 1059 | }
|
| 1060 | acct_collect(code, group_dead);
|
| 1061 | if (group_dead)
|
| 1062 | tty_audit_exit();
|
| 1063 | if (unlikely(tsk->audit_context))
|
| 1064 | audit_free(tsk);
|
| 1065 |
|
| 1066 | tsk->exit_code = code;
|
| 1067 | taskstats_exit(tsk, group_dead);
|
| 1068 |
|
| 1069 | exit_mm(tsk);
|
| 1070 |
|
| 1071 | if (group_dead)
|
| 1072 | acct_process();
|
| 1073 | trace_sched_process_exit(tsk);
|
| 1074 |
|
| 1075 | exit_sem(tsk);
|
| 1076 | exit_files(tsk);
|
| 1077 | exit_fs(tsk);
|
| 1078 | check_stack_usage();
|
| 1079 | exit_thread();
|
| 1080 | cgroup_exit(tsk, 1);
|
| 1081 | exit_keys(tsk);
|
| 1082 |
|
| 1083 | if (group_dead && tsk->signal->leader)
|
| 1084 | disassociate_ctty(1);
|
| 1085 |
|
| 1086 | module_put(task_thread_info(tsk)->exec_domain->module);
|
| 1087 | if (tsk->binfmt)
|
| 1088 | module_put(tsk->binfmt->module);
|
| 1089 |
|
| 1090 | proc_exit_connector(tsk);
|
| 1091 | exit_notify(tsk, group_dead);
|
| 1092 | #ifdef CONFIG_NUMA
|
| 1093 | mpol_put(tsk->mempolicy);
|
| 1094 | tsk->mempolicy = NULL;
|
| 1095 | #endif
|
| 1096 | #ifdef CONFIG_FUTEX
|
| 1097 | |
| 1098 | * This must happen late, after the PID is not
|
| 1099 | * hashed anymore:
|
| 1100 |
|
| 1101 | if (unlikely(!list_empty(&tsk->pi_state_list)))
|
| 1102 | exit_pi_state_list(tsk);
|
| 1103 | if (unlikely(current->pi_state_cache))
|
| 1104 | kfree(current->pi_state_cache);
|
| 1105 | #endif
|
| 1106 | |
| 1107 | * Make sure we are holding no locks:
|
| 1108 |
|
| 1109 | debug_check_no_locks_held(tsk);
|
| 1110 | |
| 1111 | * We can do this unlocked here. The futex code uses this flag
|
| 1112 | * just to verify whether the pi state cleanup has been done
|
| 1113 | * or not. In the worst case it loops once more.
|
| 1114 |
|
| 1115 | tsk->flags |= PF_EXITPIDONE;
|
| 1116 |
|
| 1117 | if (tsk->io_context)
|
| 1118 | exit_io_context();
|
| 1119 |
|
| 1120 | if (tsk->splice_pipe)
|
| 1121 | __free_pipe_info(tsk->splice_pipe);
|
| 1122 |
|
| 1123 | preempt_disable();
|
| 1124 |
|
| 1125 | tsk->state = TASK_DEAD;
|
| 1126 |
|
| 1127 | schedule();
|
| 1128 | BUG();
|
| 1129 |
|
| 1130 | for (;;)
|
| 1131 | cpu_relax();
|
| 1132 | }
|
| 1133 |
|
| 1134 | EXPORT_SYMBOL_GPL(do_exit);
|
| 1135 |
|
| 1136 | NORET_TYPE void complete_and_exit(struct completion *comp, long code)
|
| 1137 | {
|
| 1138 | if (comp)
|
| 1139 | complete(comp);
|
| 1140 |
|
| 1141 | do_exit(code);
|
| 1142 | }
|
| 1143 |
|
| 1144 | EXPORT_SYMBOL(complete_and_exit);
|
| 1145 |
|
| 1146 | asmlinkage long sys_exit(int error_code)
|
| 1147 | {
|
| 1148 | do_exit((error_code&0xff)<<8);
|
| 1149 | }
|
| 1150 |
|
| 1151 | |
| 1152 | * Take down every thread in the group. This is called by fatal signals
|
| 1153 | * as well as by sys_exit_group (below).
|
| 1154 |
|
| 1155 | NORET_TYPE void
|
| 1156 | do_group_exit(int exit_code)
|
| 1157 | {
|
| 1158 | struct signal_struct *sig = current->signal;
|
| 1159 |
|
| 1160 | BUG_ON(exit_code & 0x80);
|
| 1161 |
|
| 1162 | if (signal_group_exit(sig))
|
| 1163 | exit_code = sig->group_exit_code;
|
| 1164 | else if (!thread_group_empty(current)) {
|
| 1165 | struct sighand_struct *const sighand = current->sighand;
|
| 1166 | spin_lock_irq(&sighand->siglock);
|
| 1167 | if (signal_group_exit(sig))
|
| 1168 |
|
| 1169 | exit_code = sig->group_exit_code;
|
| 1170 | else {
|
| 1171 | sig->group_exit_code = exit_code;
|
| 1172 | sig->flags = SIGNAL_GROUP_EXIT;
|
| 1173 | zap_other_threads(current);
|
| 1174 | }
|
| 1175 | spin_unlock_irq(&sighand->siglock);
|
| 1176 | }
|
| 1177 |
|
| 1178 | do_exit(exit_code);
|
| 1179 |
|
| 1180 | }
|
| 1181 |
|
| 1182 | |
| 1183 | * this kills every thread in the thread group. Note that any externally
|
| 1184 | * wait4()-ing process will get the correct exit code - even if this
|
| 1185 | * thread is not the thread group leader.
|
| 1186 |
|
| 1187 | asmlinkage void sys_exit_group(int error_code)
|
| 1188 | {
|
| 1189 | do_group_exit((error_code & 0xff) << 8);
|
| 1190 | }
|
| 1191 |
|
| 1192 | static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
|
| 1193 | {
|
| 1194 | struct pid *pid = NULL;
|
| 1195 | if (type == PIDTYPE_PID)
|
| 1196 | pid = task->pids[type].pid;
|
| 1197 | else if (type < PIDTYPE_MAX)
|
| 1198 | pid = task->group_leader->pids[type].pid;
|
| 1199 | return pid;
|
| 1200 | }
|
| 1201 |
|
| 1202 | static int eligible_child(enum pid_type type, struct pid *pid, int options,
|
| 1203 | struct task_struct *p)
|
| 1204 | {
|
| 1205 | int err;
|
| 1206 |
|
| 1207 | if (type < PIDTYPE_MAX) {
|
| 1208 | if (task_pid_type(p, type) != pid)
|
| 1209 | return 0;
|
| 1210 | }
|
| 1211 |
|
| 1212 | |
| 1213 | * otherwise, wait for clone children *only* if __WCLONE is
|
| 1214 | * set; otherwise, wait for non-clone children *only*. (Note:
|
| 1215 | * A "clone" child here is one that reports to its parent
|
| 1216 | * using a signal other than SIGCHLD.)
|
| 1217 | if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
|
| 1218 | && !(options & __WALL))
|
| 1219 | return 0;
|
| 1220 |
|
| 1221 | err = security_task_wait(p);
|
| 1222 | if (err)
|
| 1223 | return err;
|
| 1224 |
|
| 1225 | return 1;
|
| 1226 | }
|
| 1227 |
|
| 1228 | static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
|
| 1229 | int why, int status,
|
| 1230 | struct siginfo __user *infop,
|
| 1231 | struct rusage __user *rusagep)
|
| 1232 | {
|
| 1233 | int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
|
| 1234 |
|
| 1235 | put_task_struct(p);
|
| 1236 | if (!retval)
|
| 1237 | retval = put_user(SIGCHLD, &infop->si_signo);
|
| 1238 | if (!retval)
|
| 1239 | retval = put_user(0, &infop->si_errno);
|
| 1240 | if (!retval)
|
| 1241 | retval = put_user((short)why, &infop->si_code);
|
| 1242 | if (!retval)
|
| 1243 | retval = put_user(pid, &infop->si_pid);
|
| 1244 | if (!retval)
|
| 1245 | retval = put_user(uid, &infop->si_uid);
|
| 1246 | if (!retval)
|
| 1247 | retval = put_user(status, &infop->si_status);
|
| 1248 | if (!retval)
|
| 1249 | retval = pid;
|
| 1250 | return retval;
|
| 1251 | }
|
| 1252 |
|
| 1253 | |
| 1254 | * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
|
| 1255 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
|
| 1256 | * the lock and this task is uninteresting. If we return nonzero, we have
|
| 1257 | * released the lock and the system call should return.
|
| 1258 |
|
| 1259 | static int wait_task_zombie(struct task_struct *p, int options,
|
| 1260 | struct siginfo __user *infop,
|
| 1261 | int __user *stat_addr, struct rusage __user *ru)
|
| 1262 | {
|
| 1263 | unsigned long state;
|
| 1264 | int retval, status, traced;
|
| 1265 | pid_t pid = task_pid_vnr(p);
|
| 1266 |
|
| 1267 | if (!likely(options & WEXITED))
|
| 1268 | return 0;
|
| 1269 |
|
| 1270 | if (unlikely(options & WNOWAIT)) {
|
| 1271 | uid_t uid = p->uid;
|
| 1272 | int exit_code = p->exit_code;
|
| 1273 | int why, status;
|
| 1274 |
|
| 1275 | get_task_struct(p);
|
| 1276 | read_unlock(&tasklist_lock);
|
| 1277 | if ((exit_code & 0x7f) == 0) {
|
| 1278 | why = CLD_EXITED;
|
| 1279 | status = exit_code >> 8;
|
| 1280 | } else {
|
| 1281 | why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
|
| 1282 | status = exit_code & 0x7f;
|
| 1283 | }
|
| 1284 | return wait_noreap_copyout(p, pid, uid, why,
|
| 1285 | status, infop, ru);
|
| 1286 | }
|
| 1287 |
|
| 1288 | |
| 1289 | * Try to move the task's state to DEAD
|
| 1290 | * only one thread is allowed to do this:
|
| 1291 |
|
| 1292 | state = xchg(&p->exit_state, EXIT_DEAD);
|
| 1293 | if (state != EXIT_ZOMBIE) {
|
| 1294 | BUG_ON(state != EXIT_DEAD);
|
| 1295 | return 0;
|
| 1296 | }
|
| 1297 |
|
| 1298 | traced = ptrace_reparented(p);
|
| 1299 |
|
| 1300 | if (likely(!traced)) {
|
| 1301 | struct signal_struct *psig;
|
| 1302 | struct signal_struct *sig;
|
| 1303 | struct task_cputime cputime;
|
| 1304 |
|
| 1305 | |
| 1306 | * The resource counters for the group leader are in its
|
| 1307 | * own task_struct. Those for dead threads in the group
|
| 1308 | * are in its signal_struct, as are those for the child
|
| 1309 | * processes it has previously reaped. All these
|
| 1310 | * accumulate in the parent's signal_struct c* fields.
|
| 1311 | *
|
| 1312 | * We don't bother to take a lock here to protect these
|
| 1313 | * p->signal fields, because they are only touched by
|
| 1314 | * __exit_signal, which runs with tasklist_lock
|
| 1315 | * write-locked anyway, and so is excluded here. We do
|
| 1316 | * need to protect the access to p->parent->signal fields,
|
| 1317 | * as other threads in the parent group can be right
|
| 1318 | * here reaping other children at the same time.
|
| 1319 | *
|
| 1320 | * We use thread_group_cputime() to get times for the thread
|
| 1321 | * group, which consolidates times for all threads in the
|
| 1322 | * group including the group leader.
|
| 1323 |
|
| 1324 | spin_lock_irq(&p->parent->sighand->siglock);
|
| 1325 | psig = p->parent->signal;
|
| 1326 | sig = p->signal;
|
| 1327 | thread_group_cputime(p, &cputime);
|
| 1328 | psig->cutime =
|
| 1329 | cputime_add(psig->cutime,
|
| 1330 | cputime_add(cputime.utime,
|
| 1331 | sig->cutime));
|
| 1332 | psig->cstime =
|
| 1333 | cputime_add(psig->cstime,
|
| 1334 | cputime_add(cputime.stime,
|
| 1335 | sig->cstime));
|
| 1336 | psig->cgtime =
|
| 1337 | cputime_add(psig->cgtime,
|
| 1338 | cputime_add(p->gtime,
|
| 1339 | cputime_add(sig->gtime,
|
| 1340 | sig->cgtime)));
|
| 1341 | psig->cmin_flt +=
|
| 1342 | p->min_flt + sig->min_flt + sig->cmin_flt;
|
| 1343 | psig->cmaj_flt +=
|
| 1344 | p->maj_flt + sig->maj_flt + sig->cmaj_flt;
|
| 1345 | psig->cnvcsw +=
|
| 1346 | p->nvcsw + sig->nvcsw + sig->cnvcsw;
|
| 1347 | psig->cnivcsw +=
|
| 1348 | p->nivcsw + sig->nivcsw + sig->cnivcsw;
|
| 1349 | psig->cinblock +=
|
| 1350 | task_io_get_inblock(p) +
|
| 1351 | sig->inblock + sig->cinblock;
|
| 1352 | psig->coublock +=
|
| 1353 | task_io_get_oublock(p) +
|
| 1354 | sig->oublock + sig->coublock;
|
| 1355 | task_io_accounting_add(&psig->ioac, &p->ioac);
|
| 1356 | task_io_accounting_add(&psig->ioac, &sig->ioac);
|
| 1357 | spin_unlock_irq(&p->parent->sighand->siglock);
|
| 1358 | }
|
| 1359 |
|
| 1360 | |
| 1361 | * Now we are sure this task is interesting, and no other
|
| 1362 | * thread can reap it because we set its state to EXIT_DEAD.
|
| 1363 |
|
| 1364 | read_unlock(&tasklist_lock);
|
| 1365 |
|
| 1366 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
|
| 1367 | status = (p->signal->flags & SIGNAL_GROUP_EXIT)
|
| 1368 | ? p->signal->group_exit_code : p->exit_code;
|
| 1369 | if (!retval && stat_addr)
|
| 1370 | retval = put_user(status, stat_addr);
|
| 1371 | if (!retval && infop)
|
| 1372 | retval = put_user(SIGCHLD, &infop->si_signo);
|
| 1373 | if (!retval && infop)
|
| 1374 | retval = put_user(0, &infop->si_errno);
|
| 1375 | if (!retval && infop) {
|
| 1376 | int why;
|
| 1377 |
|
| 1378 | if ((status & 0x7f) == 0) {
|
| 1379 | why = CLD_EXITED;
|
| 1380 | status >>= 8;
|
| 1381 | } else {
|
| 1382 | why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
|
| 1383 | status &= 0x7f;
|
| 1384 | }
|
| 1385 | retval = put_user((short)why, &infop->si_code);
|
| 1386 | if (!retval)
|
| 1387 | retval = put_user(status, &infop->si_status);
|
| 1388 | }
|
| 1389 | if (!retval && infop)
|
| 1390 | retval = put_user(pid, &infop->si_pid);
|
| 1391 | if (!retval && infop)
|
| 1392 | retval = put_user(p->uid, &infop->si_uid);
|
| 1393 | if (!retval)
|
| 1394 | retval = pid;
|
| 1395 |
|
| 1396 | if (traced) {
|
| 1397 | write_lock_irq(&tasklist_lock);
|
| 1398 |
|
| 1399 | ptrace_unlink(p);
|
| 1400 | |
| 1401 | * If this is not a detached task, notify the parent.
|
| 1402 | * If it's still not detached after that, don't release
|
| 1403 | * it now.
|
| 1404 |
|
| 1405 | if (!task_detached(p)) {
|
| 1406 | do_notify_parent(p, p->exit_signal);
|
| 1407 | if (!task_detached(p)) {
|
| 1408 | p->exit_state = EXIT_ZOMBIE;
|
| 1409 | p = NULL;
|
| 1410 | }
|
| 1411 | }
|
| 1412 | write_unlock_irq(&tasklist_lock);
|
| 1413 | }
|
| 1414 | if (p != NULL)
|
| 1415 | release_task(p);
|
| 1416 |
|
| 1417 | return retval;
|
| 1418 | }
|
| 1419 |
|
| 1420 | |
| 1421 | * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
|
| 1422 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
|
| 1423 | * the lock and this task is uninteresting. If we return nonzero, we have
|
| 1424 | * released the lock and the system call should return.
|
| 1425 |
|
| 1426 | static int wait_task_stopped(int ptrace, struct task_struct *p,
|
| 1427 | int options, struct siginfo __user *infop,
|
| 1428 | int __user *stat_addr, struct rusage __user *ru)
|
| 1429 | {
|
| 1430 | int retval, exit_code, why;
|
| 1431 | uid_t uid = 0;
|
| 1432 | pid_t pid;
|
| 1433 |
|
| 1434 | if (!(options & WUNTRACED))
|
| 1435 | return 0;
|
| 1436 |
|
| 1437 | exit_code = 0;
|
| 1438 | spin_lock_irq(&p->sighand->siglock);
|
| 1439 |
|
| 1440 | if (unlikely(!task_is_stopped_or_traced(p)))
|
| 1441 | goto unlock_sig;
|
| 1442 |
|
| 1443 | if (!ptrace && p->signal->group_stop_count > 0)
|
| 1444 | |
| 1445 | * A group stop is in progress and this is the group leader.
|
| 1446 | * We won't report until all threads have stopped.
|
| 1447 |
|
| 1448 | goto unlock_sig;
|
| 1449 |
|
| 1450 | exit_code = p->exit_code;
|
| 1451 | if (!exit_code)
|
| 1452 | goto unlock_sig;
|
| 1453 |
|
| 1454 | if (!unlikely(options & WNOWAIT))
|
| 1455 | p->exit_code = 0;
|
| 1456 |
|
| 1457 | uid = p->uid;
|
| 1458 | unlock_sig:
|
| 1459 | spin_unlock_irq(&p->sighand->siglock);
|
| 1460 | if (!exit_code)
|
| 1461 | return 0;
|
| 1462 |
|
| 1463 | |
| 1464 | * Now we are pretty sure this task is interesting.
|
| 1465 | * Make sure it doesn't get reaped out from under us while we
|
| 1466 | * give up the lock and then examine it below. We don't want to
|
| 1467 | * keep holding onto the tasklist_lock while we call getrusage and
|
| 1468 | * possibly take page faults for user memory.
|
| 1469 |
|
| 1470 | get_task_struct(p);
|
| 1471 | pid = task_pid_vnr(p);
|
| 1472 | why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
|
| 1473 | read_unlock(&tasklist_lock);
|
| 1474 |
|
| 1475 | if (unlikely(options & WNOWAIT))
|
| 1476 | return wait_noreap_copyout(p, pid, uid,
|
| 1477 | why, exit_code,
|
| 1478 | infop, ru);
|
| 1479 |
|
| 1480 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
|
| 1481 | if (!retval && stat_addr)
|
| 1482 | retval = put_user((exit_code << 8) | 0x7f, stat_addr);
|
| 1483 | if (!retval && infop)
|
| 1484 | retval = put_user(SIGCHLD, &infop->si_signo);
|
| 1485 | if (!retval && infop)
|
| 1486 | retval = put_user(0, &infop->si_errno);
|
| 1487 | if (!retval && infop)
|
| 1488 | retval = put_user((short)why, &infop->si_code);
|
| 1489 | if (!retval && infop)
|
| 1490 | retval = put_user(exit_code, &infop->si_status);
|
| 1491 | if (!retval && infop)
|
| 1492 | retval = put_user(pid, &infop->si_pid);
|
| 1493 | if (!retval && infop)
|
| 1494 | retval = put_user(uid, &infop->si_uid);
|
| 1495 | if (!retval)
|
| 1496 | retval = pid;
|
| 1497 | put_task_struct(p);
|
| 1498 |
|
| 1499 | BUG_ON(!retval);
|
| 1500 | return retval;
|
| 1501 | }
|
| 1502 |
|
| 1503 | |
| 1504 | * Handle do_wait work for one task in a live, non-stopped state.
|
| 1505 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
|
| 1506 | * the lock and this task is uninteresting. If we return nonzero, we have
|
| 1507 | * released the lock and the system call should return.
|
| 1508 |
|
| 1509 | static int wait_task_continued(struct task_struct *p, int options,
|
| 1510 | struct siginfo __user *infop,
|
| 1511 | int __user *stat_addr, struct rusage __user *ru)
|
| 1512 | {
|
| 1513 | int retval;
|
| 1514 | pid_t pid;
|
| 1515 | uid_t uid;
|
| 1516 |
|
| 1517 | if (!unlikely(options & WCONTINUED))
|
| 1518 | return 0;
|
| 1519 |
|
| 1520 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
|
| 1521 | return 0;
|
| 1522 |
|
| 1523 | spin_lock_irq(&p->sighand->siglock);
|
| 1524 |
|
| 1525 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
|
| 1526 | spin_unlock_irq(&p->sighand->siglock);
|
| 1527 | return 0;
|
| 1528 | }
|
| 1529 | if (!unlikely(options & WNOWAIT))
|
| 1530 | p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
|
| 1531 | spin_unlock_irq(&p->sighand->siglock);
|
| 1532 |
|
| 1533 | pid = task_pid_vnr(p);
|
| 1534 | uid = p->uid;
|
| 1535 | get_task_struct(p);
|
| 1536 | read_unlock(&tasklist_lock);
|
| 1537 |
|
| 1538 | if (!infop) {
|
| 1539 | retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
|
| 1540 | put_task_struct(p);
|
| 1541 | if (!retval && stat_addr)
|
| 1542 | retval = put_user(0xffff, stat_addr);
|
| 1543 | if (!retval)
|
| 1544 | retval = pid;
|
| 1545 | } else {
|
| 1546 | retval = wait_noreap_copyout(p, pid, uid,
|
| 1547 | CLD_CONTINUED, SIGCONT,
|
| 1548 | infop, ru);
|
| 1549 | BUG_ON(retval == 0);
|
| 1550 | }
|
| 1551 |
|
| 1552 | return retval;
|
| 1553 | }
|
| 1554 |
|
| 1555 | |
| 1556 | * Consider @p for a wait by @parent.
|
| 1557 | *
|
| 1558 | * -ECHILD should be in *@notask_error before the first call.
|
| 1559 | * Returns nonzero for a final return, when we have unlocked tasklist_lock.
|
| 1560 | * Returns zero if the search for a child should continue;
|
| 1561 | * then *@notask_error is 0 if @p is an eligible child,
|
| 1562 | * or another error from security_task_wait(), or still -ECHILD.
|
| 1563 |
|
| 1564 | static int wait_consider_task(struct task_struct *parent, int ptrace,
|
| 1565 | struct task_struct *p, int *notask_error,
|
| 1566 | enum pid_type type, struct pid *pid, int options,
|
| 1567 | struct siginfo __user *infop,
|
| 1568 | int __user *stat_addr, struct rusage __user *ru)
|
| 1569 | {
|
| 1570 | int ret = eligible_child(type, pid, options, p);
|
| 1571 | if (!ret)
|
| 1572 | return ret;
|
| 1573 |
|
| 1574 | if (unlikely(ret < 0)) {
|
| 1575 | |
| 1576 | * If we have not yet seen any eligible child,
|
| 1577 | * then let this error code replace -ECHILD.
|
| 1578 | * A permission error will give the user a clue
|
| 1579 | * to look for security policy problems, rather
|
| 1580 | * than for mysterious wait bugs.
|
| 1581 |
|
| 1582 | if (*notask_error)
|
| 1583 | *notask_error = ret;
|
| 1584 | }
|
| 1585 |
|
| 1586 | if (likely(!ptrace) && unlikely(p->ptrace)) {
|
| 1587 | |
| 1588 | * This child is hidden by ptrace.
|
| 1589 | * We aren't allowed to see it now, but eventually we will.
|
| 1590 |
|
| 1591 | *notask_error = 0;
|
| 1592 | return 0;
|
| 1593 | }
|
| 1594 |
|
| 1595 | if (p->exit_state == EXIT_DEAD)
|
| 1596 | return 0;
|
| 1597 |
|
| 1598 | |
| 1599 | * We don't reap group leaders with subthreads.
|
| 1600 |
|
| 1601 | if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p))
|
| 1602 | return wait_task_zombie(p, options, infop, stat_addr, ru);
|
| 1603 |
|
| 1604 | |
| 1605 | * It's stopped or running now, so it might
|
| 1606 | * later continue, exit, or stop again.
|
| 1607 |
|
| 1608 | *notask_error = 0;
|
| 1609 |
|
| 1610 | if (task_is_stopped_or_traced(p))
|
| 1611 | return wait_task_stopped(ptrace, p, options,
|
| 1612 | infop, stat_addr, ru);
|
| 1613 |
|
| 1614 | return wait_task_continued(p, options, infop, stat_addr, ru);
|
| 1615 | }
|
| 1616 |
|
| 1617 | |
| 1618 | * Do the work of do_wait() for one thread in the group, @tsk.
|
| 1619 | *
|
| 1620 | * -ECHILD should be in *@notask_error before the first call.
|
| 1621 | * Returns nonzero for a final return, when we have unlocked tasklist_lock.
|
| 1622 | * Returns zero if the search for a child should continue; then
|
| 1623 | * *@notask_error is 0 if there were any eligible children,
|
| 1624 | * or another error from security_task_wait(), or still -ECHILD.
|
| 1625 |
|
| 1626 | static int do_wait_thread(struct task_struct *tsk, int *notask_error,
|
| 1627 | enum pid_type type, struct pid *pid, int options,
|
| 1628 | struct siginfo __user *infop, int __user *stat_addr,
|
| 1629 | struct rusage __user *ru)
|
| 1630 | {
|
| 1631 | struct task_struct *p;
|
| 1632 |
|
| 1633 | list_for_each_entry(p, &tsk->children, sibling) {
|
| 1634 | |
| 1635 | * Do not consider detached threads.
|
| 1636 |
|
| 1637 | if (!task_detached(p)) {
|
| 1638 | int ret = wait_consider_task(tsk, 0, p, notask_error,
|
| 1639 | type, pid, options,
|
| 1640 | infop, stat_addr, ru);
|
| 1641 | if (ret)
|
| 1642 | return ret;
|
| 1643 | }
|
| 1644 | }
|
| 1645 |
|
| 1646 | return 0;
|
| 1647 | }
|
| 1648 |
|
| 1649 | static int ptrace_do_wait(struct task_struct *tsk, int *notask_error,
|
| 1650 | enum pid_type type, struct pid *pid, int options,
|
| 1651 | struct siginfo __user *infop, int __user *stat_addr,
|
| 1652 | struct rusage __user *ru)
|
| 1653 | {
|
| 1654 | struct task_struct *p;
|
| 1655 |
|
| 1656 | |
| 1657 | * Traditionally we see ptrace'd stopped tasks regardless of options.
|
| 1658 |
|
| 1659 | options |= WUNTRACED;
|
| 1660 |
|
| 1661 | list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
|
| 1662 | int ret = wait_consider_task(tsk, 1, p, notask_error,
|
| 1663 | type, pid, options,
|
| 1664 | infop, stat_addr, ru);
|
| 1665 | if (ret)
|
| 1666 | return ret;
|
| 1667 | }
|
| 1668 |
|
| 1669 | return 0;
|
| 1670 | }
|
| 1671 |
|
| 1672 | static long do_wait(enum pid_type type, struct pid *pid, int options,
|
| 1673 | struct siginfo __user *infop, int __user *stat_addr,
|
| 1674 | struct rusage __user *ru)
|
| 1675 | {
|
| 1676 | DECLARE_WAITQUEUE(wait, current);
|
| 1677 | struct task_struct *tsk;
|
| 1678 | int retval;
|
| 1679 |
|
| 1680 | trace_sched_process_wait(pid);
|
| 1681 |
|
| 1682 | add_wait_queue(¤t->signal->wait_chldexit,&wait);
|
| 1683 | repeat:
|
| 1684 | |
| 1685 | * If there is nothing that can match our critiera just get out.
|
| 1686 | * We will clear @retval to zero if we see any child that might later
|
| 1687 | * match our criteria, even if we are not able to reap it yet.
|
| 1688 |
|
| 1689 | retval = -ECHILD;
|
| 1690 | if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type])))
|
| 1691 | goto end;
|
| 1692 |
|
| 1693 | current->state = TASK_INTERRUPTIBLE;
|
| 1694 | read_lock(&tasklist_lock);
|
| 1695 | tsk = current;
|
| 1696 | do {
|
| 1697 | int tsk_result = do_wait_thread(tsk, &retval,
|
| 1698 | type, pid, options,
|
| 1699 | infop, stat_addr, ru);
|
| 1700 | if (!tsk_result)
|
| 1701 | tsk_result = ptrace_do_wait(tsk, &retval,
|
| 1702 | type, pid, options,
|
| 1703 | infop, stat_addr, ru);
|
| 1704 | if (tsk_result) {
|
| 1705 | |
| 1706 | * tasklist_lock is unlocked and we have a final result.
|
| 1707 |
|
| 1708 | retval = tsk_result;
|
| 1709 | goto end;
|
| 1710 | }
|
| 1711 |
|
| 1712 | if (options & __WNOTHREAD)
|
| 1713 | break;
|
| 1714 | tsk = next_thread(tsk);
|
| 1715 | BUG_ON(tsk->signal != current->signal);
|
| 1716 | } while (tsk != current);
|
| 1717 | read_unlock(&tasklist_lock);
|
| 1718 |
|
| 1719 | if (!retval && !(options & WNOHANG)) {
|
| 1720 | retval = -ERESTARTSYS;
|
| 1721 | if (!signal_pending(current)) {
|
| 1722 | schedule();
|
| 1723 | goto repeat;
|
| 1724 | }
|
| 1725 | }
|
| 1726 |
|
| 1727 | end:
|
| 1728 | current->state = TASK_RUNNING;
|
| 1729 | remove_wait_queue(¤t->signal->wait_chldexit,&wait);
|
| 1730 | if (infop) {
|
| 1731 | if (retval > 0)
|
| 1732 | retval = 0;
|
| 1733 | else {
|
| 1734 | |
| 1735 | * For a WNOHANG return, clear out all the fields
|
| 1736 | * we would set so the user can easily tell the
|
| 1737 | * difference.
|
| 1738 |
|
| 1739 | if (!retval)
|
| 1740 | retval = put_user(0, &infop->si_signo);
|
| 1741 | if (!retval)
|
| 1742 | retval = put_user(0, &infop->si_errno);
|
| 1743 | if (!retval)
|
| 1744 | retval = put_user(0, &infop->si_code);
|
| 1745 | if (!retval)
|
| 1746 | retval = put_user(0, &infop->si_pid);
|
| 1747 | if (!retval)
|
| 1748 | retval = put_user(0, &infop->si_uid);
|
| 1749 | if (!retval)
|
| 1750 | retval = put_user(0, &infop->si_status);
|
| 1751 | }
|
| 1752 | }
|
| 1753 | return retval;
|
| 1754 | }
|
| 1755 |
|
| 1756 | asmlinkage long sys_waitid(int which, pid_t upid,
|
| 1757 | struct siginfo __user *infop, int options,
|
| 1758 | struct rusage __user *ru)
|
| 1759 | {
|
| 1760 | struct pid *pid = NULL;
|
| 1761 | enum pid_type type;
|
| 1762 | long ret;
|
| 1763 |
|
| 1764 | if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
|
| 1765 | return -EINVAL;
|
| 1766 | if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
|
| 1767 | return -EINVAL;
|
| 1768 |
|
| 1769 | switch (which) {
|
| 1770 | case P_ALL:
|
| 1771 | type = PIDTYPE_MAX;
|
| 1772 | break;
|
| 1773 | case P_PID:
|
| 1774 | type = PIDTYPE_PID;
|
| 1775 | if (upid <= 0)
|
| 1776 | return -EINVAL;
|
| 1777 | break;
|
| 1778 | case P_PGID:
|
| 1779 | type = PIDTYPE_PGID;
|
| 1780 | if (upid <= 0)
|
| 1781 | return -EINVAL;
|
| 1782 | break;
|
| 1783 | default:
|
| 1784 | return -EINVAL;
|
| 1785 | }
|
| 1786 |
|
| 1787 | if (type < PIDTYPE_MAX)
|
| 1788 | pid = find_get_pid(upid);
|
| 1789 | ret = do_wait(type, pid, options, infop, NULL, ru);
|
| 1790 | put_pid(pid);
|
| 1791 |
|
| 1792 |
|
| 1793 | asmlinkage_protect(5, ret, which, upid, infop, options, ru);
|
| 1794 | return ret;
|
| 1795 | }
|
| 1796 |
|
| 1797 | asmlinkage long sys_wait4(pid_t upid, int __user *stat_addr,
|
| 1798 | int options, struct rusage __user *ru)
|
| 1799 | {
|
| 1800 | struct pid *pid = NULL;
|
| 1801 | enum pid_type type;
|
| 1802 | long ret;
|
| 1803 |
|
| 1804 | if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
|
| 1805 | __WNOTHREAD|__WCLONE|__WALL))
|
| 1806 | return -EINVAL;
|
| 1807 |
|
| 1808 | if (upid == -1)
|
| 1809 | type = PIDTYPE_MAX;
|
| 1810 | else if (upid < 0) {
|
| 1811 | type = PIDTYPE_PGID;
|
| 1812 | pid = find_get_pid(-upid);
|
| 1813 | } else if (upid == 0) {
|
| 1814 | type = PIDTYPE_PGID;
|
| 1815 | pid = get_pid(task_pgrp(current));
|
| 1816 | } else {
|
| 1817 | type = PIDTYPE_PID;
|
| 1818 | pid = find_get_pid(upid);
|
| 1819 | }
|
| 1820 |
|
| 1821 | ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru);
|
| 1822 | put_pid(pid);
|
| 1823 |
|
| 1824 |
|
| 1825 | asmlinkage_protect(4, ret, upid, stat_addr, options, ru);
|
| 1826 | return ret;
|
| 1827 | }
|
| 1828 |
|
| 1829 | #ifdef __ARCH_WANT_SYS_WAITPID
|
| 1830 |
|
| 1831 | |
| 1832 | * sys_waitpid() remains for compatibility. waitpid() should be
|
| 1833 | * implemented by calling sys_wait4() from libc.a.
|
| 1834 |
|
| 1835 | asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options)
|
| 1836 | {
|
| 1837 | return sys_wait4(pid, stat_addr, options, NULL);
|
| 1838 | }
|
| 1839 |
|
| 1840 | #endif
|