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 struct fdtable *fdt; 372 373 j = 0; 374 375 /* 376 * It is safe to dereference the fd table without RCU or 377 * ->file_lock because this is the last reference to the 378 * files structure. 379 */ 380 fdt = files_fdtable(files); 381 for (;;) { 382 unsigned long set; 383 i = j * __NFDBITS; 384 if (i >= fdt->max_fdset || i >= fdt->max_fds) 385 break; 386 set = fdt->open_fds->fds_bits[j++]; 387 while (set) { 388 if (set & 1) { 389 struct file * file = xchg(&fdt->fd[i], NULL); 390 if (file) 391 filp_close(file, files); 392 } 393 i++; 394 set >>= 1; 395 } 396 } 397 } 398 399 struct files_struct *get_files_struct(struct task_struct *task) 400 { 401 struct files_struct *files; 402 403 task_lock(task); 404 files = task->files; 405 if (files) 406 atomic_inc(&files->count); 407 task_unlock(task); 408 409 return files; 410 } 411 412 void fastcall put_files_struct(struct files_struct *files) 413 { 414 struct fdtable *fdt; 415 416 if (atomic_dec_and_test(&files->count)) { 417 close_files(files); 418 /* 419 * Free the fd and fdset arrays if we expanded them. 420 * If the fdtable was embedded, pass files for freeing 421 * at the end of the RCU grace period. Otherwise, 422 * you can free files immediately. 423 */ 424 fdt = files_fdtable(files); 425 if (fdt == &files->fdtab) 426 fdt->free_files = files; 427 else 428 kmem_cache_free(files_cachep, files); 429 free_fdtable(fdt); 430 } 431 } 432 433 EXPORT_SYMBOL(put_files_struct); 434 435 static inline void __exit_files(struct task_struct *tsk) 436 { 437 struct files_struct * files = tsk->files; 438 439 if (files) { 440 task_lock(tsk); 441 tsk->files = NULL; 442 task_unlock(tsk); 443 put_files_struct(files); 444 } 445 } 446 447 void exit_files(struct task_struct *tsk) 448 { 449 __exit_files(tsk); 450 } 451 452 static inline void __put_fs_struct(struct fs_struct *fs) 453 { 454 /* No need to hold fs->lock if we are killing it */ 455 if (atomic_dec_and_test(&fs->count)) { 456 dput(fs->root); 457 mntput(fs->rootmnt); 458 dput(fs->pwd); 459 mntput(fs->pwdmnt); 460 if (fs->altroot) { 461 dput(fs->altroot); 462 mntput(fs->altrootmnt); 463 } 464 kmem_cache_free(fs_cachep, fs); 465 } 466 } 467 468 void put_fs_struct(struct fs_struct *fs) 469 { 470 __put_fs_struct(fs); 471 } 472 473 static inline void __exit_fs(struct task_struct *tsk) 474 { 475 struct fs_struct * fs = tsk->fs; 476 477 if (fs) { 478 task_lock(tsk); 479 tsk->fs = NULL; 480 task_unlock(tsk); 481 __put_fs_struct(fs); 482 } 483 } 484 485 void exit_fs(struct task_struct *tsk) 486 { 487 __exit_fs(tsk); 488 } 489 490 EXPORT_SYMBOL_GPL(exit_fs); 491 492 /* 493 * Turn us into a lazy TLB process if we 494 * aren't already.. 495 */ 496 static void exit_mm(struct task_struct * tsk) 497 { 498 struct mm_struct *mm = tsk->mm; 499 500 mm_release(tsk, mm); 501 if (!mm) 502 return; 503 /* 504 * Serialize with any possible pending coredump. 505 * We must hold mmap_sem around checking core_waiters 506 * and clearing tsk->mm. The core-inducing thread 507 * will increment core_waiters for each thread in the 508 * group with ->mm != NULL. 509 */ 510 down_read(&mm->mmap_sem); 511 if (mm->core_waiters) { 512 up_read(&mm->mmap_sem); 513 down_write(&mm->mmap_sem); 514 if (!--mm->core_waiters) 515 complete(mm->core_startup_done); 516 up_write(&mm->mmap_sem); 517 518 wait_for_completion(&mm->core_done); 519 down_read(&mm->mmap_sem); 520 } 521 atomic_inc(&mm->mm_count); 522 if (mm != tsk->active_mm) BUG(); 523 /* more a memory barrier than a real lock */ 524 task_lock(tsk); 525 tsk->mm = NULL; 526 up_read(&mm->mmap_sem); 527 enter_lazy_tlb(mm, current); 528 task_unlock(tsk); 529 mmput(mm); 530 } 531 532 static inline void choose_new_parent(task_t *p, task_t *reaper, task_t *child_reaper) 533 { 534 /* 535 * Make sure we're not reparenting to ourselves and that 536 * the parent is not a zombie. 537 */ 538 BUG_ON(p == reaper || reaper->exit_state >= EXIT_ZOMBIE); 539 p->real_parent = reaper; 540 } 541 542 static inline void reparent_thread(task_t *p, task_t *father, int traced) 543 { 544 /* We don't want people slaying init. */ 545 if (p->exit_signal != -1) 546 p->exit_signal = SIGCHLD; 547 548 if (p->pdeath_signal) 549 /* We already hold the tasklist_lock here. */ 550 group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p); 551 552 /* Move the child from its dying parent to the new one. */ 553 if (unlikely(traced)) { 554 /* Preserve ptrace links if someone else is tracing this child. */ 555 list_del_init(&p->ptrace_list); 556 if (p->parent != p->real_parent) 557 list_add(&p->ptrace_list, &p->real_parent->ptrace_children); 558 } else { 559 /* If this child is being traced, then we're the one tracing it 560 * anyway, so let go of it. 561 */ 562 p->ptrace = 0; 563 list_del_init(&p->sibling); 564 p->parent = p->real_parent; 565 list_add_tail(&p->sibling, &p->parent->children); 566 567 /* If we'd notified the old parent about this child's death, 568 * also notify the new parent. 569 */ 570 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 && 571 thread_group_empty(p)) 572 do_notify_parent(p, p->exit_signal); 573 else if (p->state == TASK_TRACED) { 574 /* 575 * If it was at a trace stop, turn it into 576 * a normal stop since it's no longer being 577 * traced. 578 */ 579 ptrace_untrace(p); 580 } 581 } 582 583 /* 584 * process group orphan check 585 * Case ii: Our child is in a different pgrp 586 * than we are, and it was the only connection 587 * outside, so the child pgrp is now orphaned. 588 */ 589 if ((process_group(p) != process_group(father)) && 590 (p->signal->session == father->signal->session)) { 591 int pgrp = process_group(p); 592 593 if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) { 594 __kill_pg_info(SIGHUP, SEND_SIG_PRIV, pgrp); 595 __kill_pg_info(SIGCONT, SEND_SIG_PRIV, pgrp); 596 } 597 } 598 } 599 600 /* 601 * When we die, we re-parent all our children. 602 * Try to give them to another thread in our thread 603 * group, and if no such member exists, give it to 604 * the global child reaper process (ie "init") 605 */ 606 static inline void forget_original_parent(struct task_struct * father, 607 struct list_head *to_release) 608 { 609 struct task_struct *p, *reaper = father; 610 struct list_head *_p, *_n; 611 612 do { 613 reaper = next_thread(reaper); 614 if (reaper == father) { 615 reaper = child_reaper; 616 break; 617 } 618 } while (reaper->exit_state); 619 620 /* 621 * There are only two places where our children can be: 622 * 623 * - in our child list 624 * - in our ptraced child list 625 * 626 * Search them and reparent children. 627 */ 628 list_for_each_safe(_p, _n, &father->children) { 629 int ptrace; 630 p = list_entry(_p,struct task_struct,sibling); 631 632 ptrace = p->ptrace; 633 634 /* if father isn't the real parent, then ptrace must be enabled */ 635 BUG_ON(father != p->real_parent && !ptrace); 636 637 if (father == p->real_parent) { 638 /* reparent with a reaper, real father it's us */ 639 choose_new_parent(p, reaper, child_reaper); 640 reparent_thread(p, father, 0); 641 } else { 642 /* reparent ptraced task to its real parent */ 643 __ptrace_unlink (p); 644 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 && 645 thread_group_empty(p)) 646 do_notify_parent(p, p->exit_signal); 647 } 648 649 /* 650 * if the ptraced child is a zombie with exit_signal == -1 651 * we must collect it before we exit, or it will remain 652 * zombie forever since we prevented it from self-reap itself 653 * while it was being traced by us, to be able to see it in wait4. 654 */ 655 if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1)) 656 list_add(&p->ptrace_list, to_release); 657 } 658 list_for_each_safe(_p, _n, &father->ptrace_children) { 659 p = list_entry(_p,struct task_struct,ptrace_list); 660 choose_new_parent(p, reaper, child_reaper); 661 reparent_thread(p, father, 1); 662 } 663 } 664 665 /* 666 * Send signals to all our closest relatives so that they know 667 * to properly mourn us.. 668 */ 669 static void exit_notify(struct task_struct *tsk) 670 { 671 int state; 672 struct task_struct *t; 673 struct list_head ptrace_dead, *_p, *_n; 674 675 if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT) 676 && !thread_group_empty(tsk)) { 677 /* 678 * This occurs when there was a race between our exit 679 * syscall and a group signal choosing us as the one to 680 * wake up. It could be that we are the only thread 681 * alerted to check for pending signals, but another thread 682 * should be woken now to take the signal since we will not. 683 * Now we'll wake all the threads in the group just to make 684 * sure someone gets all the pending signals. 685 */ 686 read_lock(&tasklist_lock); 687 spin_lock_irq(&tsk->sighand->siglock); 688 for (t = next_thread(tsk); t != tsk; t = next_thread(t)) 689 if (!signal_pending(t) && !(t->flags & PF_EXITING)) { 690 recalc_sigpending_tsk(t); 691 if (signal_pending(t)) 692 signal_wake_up(t, 0); 693 } 694 spin_unlock_irq(&tsk->sighand->siglock); 695 read_unlock(&tasklist_lock); 696 } 697 698 write_lock_irq(&tasklist_lock); 699 700 /* 701 * This does two things: 702 * 703 * A. Make init inherit all the child processes 704 * B. Check to see if any process groups have become orphaned 705 * as a result of our exiting, and if they have any stopped 706 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) 707 */ 708 709 INIT_LIST_HEAD(&ptrace_dead); 710 forget_original_parent(tsk, &ptrace_dead); 711 BUG_ON(!list_empty(&tsk->children)); 712 BUG_ON(!list_empty(&tsk->ptrace_children)); 713 714 /* 715 * Check to see if any process groups have become orphaned 716 * as a result of our exiting, and if they have any stopped 717 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) 718 * 719 * Case i: Our father is in a different pgrp than we are 720 * and we were the only connection outside, so our pgrp 721 * is about to become orphaned. 722 */ 723 724 t = tsk->real_parent; 725 726 if ((process_group(t) != process_group(tsk)) && 727 (t->signal->session == tsk->signal->session) && 728 will_become_orphaned_pgrp(process_group(tsk), tsk) && 729 has_stopped_jobs(process_group(tsk))) { 730 __kill_pg_info(SIGHUP, SEND_SIG_PRIV, process_group(tsk)); 731 __kill_pg_info(SIGCONT, SEND_SIG_PRIV, process_group(tsk)); 732 } 733 734 /* Let father know we died 735 * 736 * Thread signals are configurable, but you aren't going to use 737 * that to send signals to arbitary processes. 738 * That stops right now. 739 * 740 * If the parent exec id doesn't match the exec id we saved 741 * when we started then we know the parent has changed security 742 * domain. 743 * 744 * If our self_exec id doesn't match our parent_exec_id then 745 * we have changed execution domain as these two values started 746 * the same after a fork. 747 * 748 */ 749 750 if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 && 751 ( tsk->parent_exec_id != t->self_exec_id || 752 tsk->self_exec_id != tsk->parent_exec_id) 753 && !capable(CAP_KILL)) 754 tsk->exit_signal = SIGCHLD; 755 756 757 /* If something other than our normal parent is ptracing us, then 758 * send it a SIGCHLD instead of honoring exit_signal. exit_signal 759 * only has special meaning to our real parent. 760 */ 761 if (tsk->exit_signal != -1 && thread_group_empty(tsk)) { 762 int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD; 763 do_notify_parent(tsk, signal); 764 } else if (tsk->ptrace) { 765 do_notify_parent(tsk, SIGCHLD); 766 } 767 768 state = EXIT_ZOMBIE; 769 if (tsk->exit_signal == -1 && 770 (likely(tsk->ptrace == 0) || 771 unlikely(tsk->parent->signal->flags & SIGNAL_GROUP_EXIT))) 772 state = EXIT_DEAD; 773 tsk->exit_state = state; 774 775 write_unlock_irq(&tasklist_lock); 776 777 list_for_each_safe(_p, _n, &ptrace_dead) { 778 list_del_init(_p); 779 t = list_entry(_p,struct task_struct,ptrace_list); 780 release_task(t); 781 } 782 783 /* If the process is dead, release it - nobody will wait for it */ 784 if (state == EXIT_DEAD) 785 release_task(tsk); 786 } 787 788 fastcall NORET_TYPE void do_exit(long code) 789 { 790 struct task_struct *tsk = current; 791 int group_dead; 792 793 profile_task_exit(tsk); 794 795 WARN_ON(atomic_read(&tsk->fs_excl)); 796 797 if (unlikely(in_interrupt())) 798 panic("Aiee, killing interrupt handler!"); 799 if (unlikely(!tsk->pid)) 800 panic("Attempted to kill the idle task!"); 801 if (unlikely(tsk->pid == 1)) 802 panic("Attempted to kill init!"); 803 if (tsk->io_context) 804 exit_io_context(); 805 806 if (unlikely(current->ptrace & PT_TRACE_EXIT)) { 807 current->ptrace_message = code; 808 ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP); 809 } 810 811 /* 812 * We're taking recursive faults here in do_exit. Safest is to just 813 * leave this task alone and wait for reboot. 814 */ 815 if (unlikely(tsk->flags & PF_EXITING)) { 816 printk(KERN_ALERT 817 "Fixing recursive fault but reboot is needed!\n"); 818 set_current_state(TASK_UNINTERRUPTIBLE); 819 schedule(); 820 } 821 822 tsk->flags |= PF_EXITING; 823 824 /* 825 * Make sure we don't try to process any timer firings 826 * while we are already exiting. 827 */ 828 tsk->it_virt_expires = cputime_zero; 829 tsk->it_prof_expires = cputime_zero; 830 tsk->it_sched_expires = 0; 831 832 if (unlikely(in_atomic())) 833 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", 834 current->comm, current->pid, 835 preempt_count()); 836 837 acct_update_integrals(tsk); 838 if (tsk->mm) { 839 update_hiwater_rss(tsk->mm); 840 update_hiwater_vm(tsk->mm); 841 } 842 group_dead = atomic_dec_and_test(&tsk->signal->live); 843 if (group_dead) { 844 del_timer_sync(&tsk->signal->real_timer); 845 exit_itimers(tsk->signal); 846 acct_process(code); 847 } 848 exit_mm(tsk); 849 850 exit_sem(tsk); 851 __exit_files(tsk); 852 __exit_fs(tsk); 853 exit_namespace(tsk); 854 exit_thread(); 855 cpuset_exit(tsk); 856 exit_keys(tsk); 857 858 if (group_dead && tsk->signal->leader) 859 disassociate_ctty(1); 860 861 module_put(tsk->thread_info->exec_domain->module); 862 if (tsk->binfmt) 863 module_put(tsk->binfmt->module); 864 865 tsk->exit_code = code; 866 exit_notify(tsk); 867 #ifdef CONFIG_NUMA 868 mpol_free(tsk->mempolicy); 869 tsk->mempolicy = NULL; 870 #endif 871 872 /* PF_DEAD causes final put_task_struct after we schedule. */ 873 preempt_disable(); 874 BUG_ON(tsk->flags & PF_DEAD); 875 tsk->flags |= PF_DEAD; 876 877 schedule(); 878 BUG(); 879 /* Avoid "noreturn function does return". */ 880 for (;;) ; 881 } 882 883 EXPORT_SYMBOL_GPL(do_exit); 884 885 NORET_TYPE void complete_and_exit(struct completion *comp, long code) 886 { 887 if (comp) 888 complete(comp); 889 890 do_exit(code); 891 } 892 893 EXPORT_SYMBOL(complete_and_exit); 894 895 asmlinkage long sys_exit(int error_code) 896 { 897 do_exit((error_code&0xff)<<8); 898 } 899 900 task_t fastcall *next_thread(const task_t *p) 901 { 902 return pid_task(p->pids[PIDTYPE_TGID].pid_list.next, PIDTYPE_TGID); 903 } 904 905 EXPORT_SYMBOL(next_thread); 906 907 /* 908 * Take down every thread in the group. This is called by fatal signals 909 * as well as by sys_exit_group (below). 910 */ 911 NORET_TYPE void 912 do_group_exit(int exit_code) 913 { 914 BUG_ON(exit_code & 0x80); /* core dumps don't get here */ 915 916 if (current->signal->flags & SIGNAL_GROUP_EXIT) 917 exit_code = current->signal->group_exit_code; 918 else if (!thread_group_empty(current)) { 919 struct signal_struct *const sig = current->signal; 920 struct sighand_struct *const sighand = current->sighand; 921 read_lock(&tasklist_lock); 922 spin_lock_irq(&sighand->siglock); 923 if (sig->flags & SIGNAL_GROUP_EXIT) 924 /* Another thread got here before we took the lock. */ 925 exit_code = sig->group_exit_code; 926 else { 927 sig->flags = SIGNAL_GROUP_EXIT; 928 sig->group_exit_code = exit_code; 929 zap_other_threads(current); 930 } 931 spin_unlock_irq(&sighand->siglock); 932 read_unlock(&tasklist_lock); 933 } 934 935 do_exit(exit_code); 936 /* NOTREACHED */ 937 } 938 939 /* 940 * this kills every thread in the thread group. Note that any externally 941 * wait4()-ing process will get the correct exit code - even if this 942 * thread is not the thread group leader. 943 */ 944 asmlinkage void sys_exit_group(int error_code) 945 { 946 do_group_exit((error_code & 0xff) << 8); 947 } 948 949 static int eligible_child(pid_t pid, int options, task_t *p) 950 { 951 if (pid > 0) { 952 if (p->pid != pid) 953 return 0; 954 } else if (!pid) { 955 if (process_group(p) != process_group(current)) 956 return 0; 957 } else if (pid != -1) { 958 if (process_group(p) != -pid) 959 return 0; 960 } 961 962 /* 963 * Do not consider detached threads that are 964 * not ptraced: 965 */ 966 if (p->exit_signal == -1 && !p->ptrace) 967 return 0; 968 969 /* Wait for all children (clone and not) if __WALL is set; 970 * otherwise, wait for clone children *only* if __WCLONE is 971 * set; otherwise, wait for non-clone children *only*. (Note: 972 * A "clone" child here is one that reports to its parent 973 * using a signal other than SIGCHLD.) */ 974 if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0)) 975 && !(options & __WALL)) 976 return 0; 977 /* 978 * Do not consider thread group leaders that are 979 * in a non-empty thread group: 980 */ 981 if (current->tgid != p->tgid && delay_group_leader(p)) 982 return 2; 983 984 if (security_task_wait(p)) 985 return 0; 986 987 return 1; 988 } 989 990 static int wait_noreap_copyout(task_t *p, pid_t pid, uid_t uid, 991 int why, int status, 992 struct siginfo __user *infop, 993 struct rusage __user *rusagep) 994 { 995 int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0; 996 put_task_struct(p); 997 if (!retval) 998 retval = put_user(SIGCHLD, &infop->si_signo); 999 if (!retval) 1000 retval = put_user(0, &infop->si_errno); 1001 if (!retval) 1002 retval = put_user((short)why, &infop->si_code); 1003 if (!retval) 1004 retval = put_user(pid, &infop->si_pid); 1005 if (!retval) 1006 retval = put_user(uid, &infop->si_uid); 1007 if (!retval) 1008 retval = put_user(status, &infop->si_status); 1009 if (!retval) 1010 retval = pid; 1011 return retval; 1012 } 1013 1014 /* 1015 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold 1016 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold 1017 * the lock and this task is uninteresting. If we return nonzero, we have 1018 * released the lock and the system call should return. 1019 */ 1020 static int wait_task_zombie(task_t *p, int noreap, 1021 struct siginfo __user *infop, 1022 int __user *stat_addr, struct rusage __user *ru) 1023 { 1024 unsigned long state; 1025 int retval; 1026 int status; 1027 1028 if (unlikely(noreap)) { 1029 pid_t pid = p->pid; 1030 uid_t uid = p->uid; 1031 int exit_code = p->exit_code; 1032 int why, status; 1033 1034 if (unlikely(p->exit_state != EXIT_ZOMBIE)) 1035 return 0; 1036 if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) 1037 return 0; 1038 get_task_struct(p); 1039 read_unlock(&tasklist_lock); 1040 if ((exit_code & 0x7f) == 0) { 1041 why = CLD_EXITED; 1042 status = exit_code >> 8; 1043 } else { 1044 why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED; 1045 status = exit_code & 0x7f; 1046 } 1047 return wait_noreap_copyout(p, pid, uid, why, 1048 status, infop, ru); 1049 } 1050 1051 /* 1052 * Try to move the task's state to DEAD 1053 * only one thread is allowed to do this: 1054 */ 1055 state = xchg(&p->exit_state, EXIT_DEAD); 1056 if (state != EXIT_ZOMBIE) { 1057 BUG_ON(state != EXIT_DEAD); 1058 return 0; 1059 } 1060 if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) { 1061 /* 1062 * This can only happen in a race with a ptraced thread 1063 * dying on another processor. 1064 */ 1065 return 0; 1066 } 1067 1068 if (likely(p->real_parent == p->parent) && likely(p->signal)) { 1069 /* 1070 * The resource counters for the group leader are in its 1071 * own task_struct. Those for dead threads in the group 1072 * are in its signal_struct, as are those for the child 1073 * processes it has previously reaped. All these 1074 * accumulate in the parent's signal_struct c* fields. 1075 * 1076 * We don't bother to take a lock here to protect these 1077 * p->signal fields, because they are only touched by 1078 * __exit_signal, which runs with tasklist_lock 1079 * write-locked anyway, and so is excluded here. We do 1080 * need to protect the access to p->parent->signal fields, 1081 * as other threads in the parent group can be right 1082 * here reaping other children at the same time. 1083 */ 1084 spin_lock_irq(&p->parent->sighand->siglock); 1085 p->parent->signal->cutime = 1086 cputime_add(p->parent->signal->cutime, 1087 cputime_add(p->utime, 1088 cputime_add(p->signal->utime, 1089 p->signal->cutime))); 1090 p->parent->signal->cstime = 1091 cputime_add(p->parent->signal->cstime, 1092 cputime_add(p->stime, 1093 cputime_add(p->signal->stime, 1094 p->signal->cstime))); 1095 p->parent->signal->cmin_flt += 1096 p->min_flt + p->signal->min_flt + p->signal->cmin_flt; 1097 p->parent->signal->cmaj_flt += 1098 p->maj_flt + p->signal->maj_flt + p->signal->cmaj_flt; 1099 p->parent->signal->cnvcsw += 1100 p->nvcsw + p->signal->nvcsw + p->signal->cnvcsw; 1101 p->parent->signal->cnivcsw += 1102 p->nivcsw + p->signal->nivcsw + p->signal->cnivcsw; 1103 spin_unlock_irq(&p->parent->sighand->siglock); 1104 } 1105 1106 /* 1107 * Now we are sure this task is interesting, and no other 1108 * thread can reap it because we set its state to EXIT_DEAD. 1109 */ 1110 read_unlock(&tasklist_lock); 1111 1112 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; 1113 status = (p->signal->flags & SIGNAL_GROUP_EXIT) 1114 ? p->signal->group_exit_code : p->exit_code; 1115 if (!retval && stat_addr) 1116 retval = put_user(status, stat_addr); 1117 if (!retval && infop) 1118 retval = put_user(SIGCHLD, &infop->si_signo); 1119 if (!retval && infop) 1120 retval = put_user(0, &infop->si_errno); 1121 if (!retval && infop) { 1122 int why; 1123 1124 if ((status & 0x7f) == 0) { 1125 why = CLD_EXITED; 1126 status >>= 8; 1127 } else { 1128 why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED; 1129 status &= 0x7f; 1130 } 1131 retval = put_user((short)why, &infop->si_code); 1132 if (!retval) 1133 retval = put_user(status, &infop->si_status); 1134 } 1135 if (!retval && infop) 1136 retval = put_user(p->pid, &infop->si_pid); 1137 if (!retval && infop) 1138 retval = put_user(p->uid, &infop->si_uid); 1139 if (retval) { 1140 // TODO: is this safe? 1141 p->exit_state = EXIT_ZOMBIE; 1142 return retval; 1143 } 1144 retval = p->pid; 1145 if (p->real_parent != p->parent) { 1146 write_lock_irq(&tasklist_lock); 1147 /* Double-check with lock held. */ 1148 if (p->real_parent != p->parent) { 1149 __ptrace_unlink(p); 1150 // TODO: is this safe? 1151 p->exit_state = EXIT_ZOMBIE; 1152 /* 1153 * If this is not a detached task, notify the parent. 1154 * If it's still not detached after that, don't release 1155 * it now. 1156 */ 1157 if (p->exit_signal != -1) { 1158 do_notify_parent(p, p->exit_signal); 1159 if (p->exit_signal != -1) 1160 p = NULL; 1161 } 1162 } 1163 write_unlock_irq(&tasklist_lock); 1164 } 1165 if (p != NULL) 1166 release_task(p); 1167 BUG_ON(!retval); 1168 return retval; 1169 } 1170 1171 /* 1172 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold 1173 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold 1174 * the lock and this task is uninteresting. If we return nonzero, we have 1175 * released the lock and the system call should return. 1176 */ 1177 static int wait_task_stopped(task_t *p, int delayed_group_leader, int noreap, 1178 struct siginfo __user *infop, 1179 int __user *stat_addr, struct rusage __user *ru) 1180 { 1181 int retval, exit_code; 1182 1183 if (!p->exit_code) 1184 return 0; 1185 if (delayed_group_leader && !(p->ptrace & PT_PTRACED) && 1186 p->signal && p->signal->group_stop_count > 0) 1187 /* 1188 * A group stop is in progress and this is the group leader. 1189 * We won't report until all threads have stopped. 1190 */ 1191 return 0; 1192 1193 /* 1194 * Now we are pretty sure this task is interesting. 1195 * Make sure it doesn't get reaped out from under us while we 1196 * give up the lock and then examine it below. We don't want to 1197 * keep holding onto the tasklist_lock while we call getrusage and 1198 * possibly take page faults for user memory. 1199 */ 1200 get_task_struct(p); 1201 read_unlock(&tasklist_lock); 1202 1203 if (unlikely(noreap)) { 1204 pid_t pid = p->pid; 1205 uid_t uid = p->uid; 1206 int why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED; 1207 1208 exit_code = p->exit_code; 1209 if (unlikely(!exit_code) || 1210 unlikely(p->state & TASK_TRACED)) 1211 goto bail_ref; 1212 return wait_noreap_copyout(p, pid, uid, 1213 why, (exit_code << 8) | 0x7f, 1214 infop, ru); 1215 } 1216 1217 write_lock_irq(&tasklist_lock); 1218 1219 /* 1220 * This uses xchg to be atomic with the thread resuming and setting 1221 * it. It must also be done with the write lock held to prevent a 1222 * race with the EXIT_ZOMBIE case. 1223 */ 1224 exit_code = xchg(&p->exit_code, 0); 1225 if (unlikely(p->exit_state)) { 1226 /* 1227 * The task resumed and then died. Let the next iteration 1228 * catch it in EXIT_ZOMBIE. Note that exit_code might 1229 * already be zero here if it resumed and did _exit(0). 1230 * The task itself is dead and won't touch exit_code again; 1231 * other processors in this function are locked out. 1232 */ 1233 p->exit_code = exit_code; 1234 exit_code = 0; 1235 } 1236 if (unlikely(exit_code == 0)) { 1237 /* 1238 * Another thread in this function got to it first, or it 1239 * resumed, or it resumed and then died. 1240 */ 1241 write_unlock_irq(&tasklist_lock); 1242 bail_ref: 1243 put_task_struct(p); 1244 /* 1245 * We are returning to the wait loop without having successfully 1246 * removed the process and having released the lock. We cannot 1247 * continue, since the "p" task pointer is potentially stale. 1248 * 1249 * Return -EAGAIN, and do_wait() will restart the loop from the 1250 * beginning. Do _not_ re-acquire the lock. 1251 */ 1252 return -EAGAIN; 1253 } 1254 1255 /* move to end of parent's list to avoid starvation */ 1256 remove_parent(p); 1257 add_parent(p, p->parent); 1258 1259 write_unlock_irq(&tasklist_lock); 1260 1261 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; 1262 if (!retval && stat_addr) 1263 retval = put_user((exit_code << 8) | 0x7f, stat_addr); 1264 if (!retval && infop) 1265 retval = put_user(SIGCHLD, &infop->si_signo); 1266 if (!retval && infop) 1267 retval = put_user(0, &infop->si_errno); 1268 if (!retval && infop) 1269 retval = put_user((short)((p->ptrace & PT_PTRACED) 1270 ? CLD_TRAPPED : CLD_STOPPED), 1271 &infop->si_code); 1272 if (!retval && infop) 1273 retval = put_user(exit_code, &infop->si_status); 1274 if (!retval && infop) 1275 retval = put_user(p->pid, &infop->si_pid); 1276 if (!retval && infop) 1277 retval = put_user(p->uid, &infop->si_uid); 1278 if (!retval) 1279 retval = p->pid; 1280 put_task_struct(p); 1281 1282 BUG_ON(!retval); 1283 return retval; 1284 } 1285 1286 /* 1287 * Handle do_wait work for one task in a live, non-stopped state. 1288 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold 1289 * the lock and this task is uninteresting. If we return nonzero, we have 1290 * released the lock and the system call should return. 1291 */ 1292 static int wait_task_continued(task_t *p, int noreap, 1293 struct siginfo __user *infop, 1294 int __user *stat_addr, struct rusage __user *ru) 1295 { 1296 int retval; 1297 pid_t pid; 1298 uid_t uid; 1299 1300 if (unlikely(!p->signal)) 1301 return 0; 1302 1303 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) 1304 return 0; 1305 1306 spin_lock_irq(&p->sighand->siglock); 1307 /* Re-check with the lock held. */ 1308 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) { 1309 spin_unlock_irq(&p->sighand->siglock); 1310 return 0; 1311 } 1312 if (!noreap) 1313 p->signal->flags &= ~SIGNAL_STOP_CONTINUED; 1314 spin_unlock_irq(&p->sighand->siglock); 1315 1316 pid = p->pid; 1317 uid = p->uid; 1318 get_task_struct(p); 1319 read_unlock(&tasklist_lock); 1320 1321 if (!infop) { 1322 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; 1323 put_task_struct(p); 1324 if (!retval && stat_addr) 1325 retval = put_user(0xffff, stat_addr); 1326 if (!retval) 1327 retval = p->pid; 1328 } else { 1329 retval = wait_noreap_copyout(p, pid, uid, 1330 CLD_CONTINUED, SIGCONT, 1331 infop, ru); 1332 BUG_ON(retval == 0); 1333 } 1334 1335 return retval; 1336 } 1337 1338 1339 static inline int my_ptrace_child(struct task_struct *p) 1340 { 1341 if (!(p->ptrace & PT_PTRACED)) 1342 return 0; 1343 if (!(p->ptrace & PT_ATTACHED)) 1344 return 1; 1345 /* 1346 * This child was PTRACE_ATTACH'd. We should be seeing it only if 1347 * we are the attacher. If we are the real parent, this is a race 1348 * inside ptrace_attach. It is waiting for the tasklist_lock, 1349 * which we have to switch the parent links, but has already set 1350 * the flags in p->ptrace. 1351 */ 1352 return (p->parent != p->real_parent); 1353 } 1354 1355 static long do_wait(pid_t pid, int options, struct siginfo __user *infop, 1356 int __user *stat_addr, struct rusage __user *ru) 1357 { 1358 DECLARE_WAITQUEUE(wait, current); 1359 struct task_struct *tsk; 1360 int flag, retval; 1361 1362 add_wait_queue(¤t->signal->wait_chldexit,&wait); 1363 repeat: 1364 /* 1365 * We will set this flag if we see any child that might later 1366 * match our criteria, even if we are not able to reap it yet. 1367 */ 1368 flag = 0; 1369 current->state = TASK_INTERRUPTIBLE; 1370 read_lock(&tasklist_lock); 1371 tsk = current; 1372 do { 1373 struct task_struct *p; 1374 struct list_head *_p; 1375 int ret; 1376 1377 list_for_each(_p,&tsk->children) { 1378 p = list_entry(_p,struct task_struct,sibling); 1379 1380 ret = eligible_child(pid, options, p); 1381 if (!ret) 1382 continue; 1383 1384 switch (p->state) { 1385 case TASK_TRACED: 1386 /* 1387 * When we hit the race with PTRACE_ATTACH, 1388 * we will not report this child. But the 1389 * race means it has not yet been moved to 1390 * our ptrace_children list, so we need to 1391 * set the flag here to avoid a spurious ECHILD 1392 * when the race happens with the only child. 1393 */ 1394 flag = 1; 1395 if (!my_ptrace_child(p)) 1396 continue; 1397 /*FALLTHROUGH*/ 1398 case TASK_STOPPED: 1399 /* 1400 * It's stopped now, so it might later 1401 * continue, exit, or stop again. 1402 */ 1403 flag = 1; 1404 if (!(options & WUNTRACED) && 1405 !my_ptrace_child(p)) 1406 continue; 1407 retval = wait_task_stopped(p, ret == 2, 1408 (options & WNOWAIT), 1409 infop, 1410 stat_addr, ru); 1411 if (retval == -EAGAIN) 1412 goto repeat; 1413 if (retval != 0) /* He released the lock. */ 1414 goto end; 1415 break; 1416 default: 1417 // case EXIT_DEAD: 1418 if (p->exit_state == EXIT_DEAD) 1419 continue; 1420 // case EXIT_ZOMBIE: 1421 if (p->exit_state == EXIT_ZOMBIE) { 1422 /* 1423 * Eligible but we cannot release 1424 * it yet: 1425 */ 1426 if (ret == 2) 1427 goto check_continued; 1428 if (!likely(options & WEXITED)) 1429 continue; 1430 retval = wait_task_zombie( 1431 p, (options & WNOWAIT), 1432 infop, stat_addr, ru); 1433 /* He released the lock. */ 1434 if (retval != 0) 1435 goto end; 1436 break; 1437 } 1438 check_continued: 1439 /* 1440 * It's running now, so it might later 1441 * exit, stop, or stop and then continue. 1442 */ 1443 flag = 1; 1444 if (!unlikely(options & WCONTINUED)) 1445 continue; 1446 retval = wait_task_continued( 1447 p, (options & WNOWAIT), 1448 infop, stat_addr, ru); 1449 if (retval != 0) /* He released the lock. */ 1450 goto end; 1451 break; 1452 } 1453 } 1454 if (!flag) { 1455 list_for_each(_p, &tsk->ptrace_children) { 1456 p = list_entry(_p, struct task_struct, 1457 ptrace_list); 1458 if (!eligible_child(pid, options, p)) 1459 continue; 1460 flag = 1; 1461 break; 1462 } 1463 } 1464 if (options & __WNOTHREAD) 1465 break; 1466 tsk = next_thread(tsk); 1467 if (tsk->signal != current->signal) 1468 BUG(); 1469 } while (tsk != current); 1470 1471 read_unlock(&tasklist_lock); 1472 if (flag) { 1473 retval = 0; 1474 if (options & WNOHANG) 1475 goto end; 1476 retval = -ERESTARTSYS; 1477 if (signal_pending(current)) 1478 goto end; 1479 schedule(); 1480 goto repeat; 1481 } 1482 retval = -ECHILD; 1483 end: 1484 current->state = TASK_RUNNING; 1485 remove_wait_queue(¤t->signal->wait_chldexit,&wait); 1486 if (infop) { 1487 if (retval > 0) 1488 retval = 0; 1489 else { 1490 /* 1491 * For a WNOHANG return, clear out all the fields 1492 * we would set so the user can easily tell the 1493 * difference. 1494 */ 1495 if (!retval) 1496 retval = put_user(0, &infop->si_signo); 1497 if (!retval) 1498 retval = put_user(0, &infop->si_errno); 1499 if (!retval) 1500 retval = put_user(0, &infop->si_code); 1501 if (!retval) 1502 retval = put_user(0, &infop->si_pid); 1503 if (!retval) 1504 retval = put_user(0, &infop->si_uid); 1505 if (!retval) 1506 retval = put_user(0, &infop->si_status); 1507 } 1508 } 1509 return retval; 1510 } 1511 1512 asmlinkage long sys_waitid(int which, pid_t pid, 1513 struct siginfo __user *infop, int options, 1514 struct rusage __user *ru) 1515 { 1516 long ret; 1517 1518 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED)) 1519 return -EINVAL; 1520 if (!(options & (WEXITED|WSTOPPED|WCONTINUED))) 1521 return -EINVAL; 1522 1523 switch (which) { 1524 case P_ALL: 1525 pid = -1; 1526 break; 1527 case P_PID: 1528 if (pid <= 0) 1529 return -EINVAL; 1530 break; 1531 case P_PGID: 1532 if (pid <= 0) 1533 return -EINVAL; 1534 pid = -pid; 1535 break; 1536 default: 1537 return -EINVAL; 1538 } 1539 1540 ret = do_wait(pid, options, infop, NULL, ru); 1541 1542 /* avoid REGPARM breakage on x86: */ 1543 prevent_tail_call(ret); 1544 return ret; 1545 } 1546 1547 asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr, 1548 int options, struct rusage __user *ru) 1549 { 1550 long ret; 1551 1552 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED| 1553 __WNOTHREAD|__WCLONE|__WALL)) 1554 return -EINVAL; 1555 ret = do_wait(pid, options | WEXITED, NULL, stat_addr, ru); 1556 1557 /* avoid REGPARM breakage on x86: */ 1558 prevent_tail_call(ret); 1559 return ret; 1560 } 1561 1562 #ifdef __ARCH_WANT_SYS_WAITPID 1563 1564 /* 1565 * sys_waitpid() remains for compatibility. waitpid() should be 1566 * implemented by calling sys_wait4() from libc.a. 1567 */ 1568 asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options) 1569 { 1570 return sys_wait4(pid, stat_addr, options, NULL); 1571 } 1572 1573 #endif 1574