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