kernel/exit.c

/* */
This source file includes following definitions.
generate
force_sig
send_sig
notify_parent
release
bad_task_ptr
audit_ptree
session_of_pgrp
kill_pg
kill_sl
kill_proc
sys_kill
is_orphaned_pgrp
has_stopped_jobs
forget_original_parent
__exit_files
exit_files
__exit_fs
exit_fs
__exit_sighand
exit_sighand
__exit_mm
exit_mm
exit_notify
do_exit
sys_exit
sys_wait4
sys_waitpid
   1 /*
   2  *  linux/kernel/exit.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6 
   7 #undef DEBUG_PROC_TREE
   8 
   9 #include <linux/wait.h>
  10 #include <linux/errno.h>
  11 #include <linux/signal.h>
  12 #include <linux/sched.h>
  13 #include <linux/kernel.h>
  14 #include <linux/resource.h>
  15 #include <linux/mm.h>
  16 #include <linux/tty.h>
  17 #include <linux/malloc.h>
  18 
  19 #include <asm/segment.h>
  20 #include <asm/pgtable.h>
  21 
  22 extern void sem_exit (void);
  23 extern void acct_process (long exitcode);
  24 extern void kerneld_exit(void);
  25 
  26 int getrusage(struct task_struct *, int, struct rusage *);
  27 
  28 static inline void generate(unsigned long sig, struct task_struct * p)
     /*  */
  29 {
  30         unsigned long mask = 1 << (sig-1);
  31         struct sigaction * sa = sig + p->sig->action - 1;
  32 
  33         /*
  34          * Optimize away the signal, if it's a signal that can
  35          * be handled immediately (ie non-blocked and untraced)
  36          * and that is ignored (either explicitly or by default)
  37          */
  38         if (!(mask & p->blocked) && !(p->flags & PF_PTRACED)) {
  39                 /* don't bother with ignored signals (but SIGCHLD is special) */
  40                 if (sa->sa_handler == SIG_IGN && sig != SIGCHLD)
  41                         return;
  42                 /* some signals are ignored by default.. (but SIGCONT already did its deed) */
  43                 if ((sa->sa_handler == SIG_DFL) &&
  44                     (sig == SIGCONT || sig == SIGCHLD || sig == SIGWINCH || sig == SIGURG))
  45                         return;
  46         }
  47         p->signal |= mask;
  48         if (p->state == TASK_INTERRUPTIBLE && (p->signal & ~p->blocked))
  49                 wake_up_process(p);
  50 }
  51 
  52 /*
  53  * Force a signal that the process can't ignore: if necessary
  54  * we unblock the signal and change any SIG_IGN to SIG_DFL.
  55  */
  56 void force_sig(unsigned long sig, struct task_struct * p)
     /*  */
  57 {
  58         sig--;
  59         if (p->sig) {
  60                 unsigned long mask = 1UL << sig;
  61                 struct sigaction *sa = p->sig->action + sig;
  62                 p->signal |= mask;
  63                 p->blocked &= ~mask;
  64                 if (sa->sa_handler == SIG_IGN)
  65                         sa->sa_handler = SIG_DFL;
  66                 if (p->state == TASK_INTERRUPTIBLE)
  67                         wake_up_process(p);
  68         }
  69 }
  70                 
  71 
  72 int send_sig(unsigned long sig,struct task_struct * p,int priv)
     /*  */
  73 {
  74         if (!p || sig > 32)
  75                 return -EINVAL;
  76         if (!priv && ((sig != SIGCONT) || (current->session != p->session)) &&
  77             (current->euid ^ p->euid) && (current->euid ^ p->uid) &&
  78             (current->uid ^ p->euid) && (current->uid ^ p->uid) &&
  79             !suser())
  80                 return -EPERM;
  81         if (!sig)
  82                 return 0;
  83         /*
  84          * Forget it if the process is already zombie'd.
  85          */
  86         if (!p->sig)
  87                 return 0;
  88         if ((sig == SIGKILL) || (sig == SIGCONT)) {
  89                 if (p->state == TASK_STOPPED)
  90                         wake_up_process(p);
  91                 p->exit_code = 0;
  92                 p->signal &= ~( (1<<(SIGSTOP-1)) | (1<<(SIGTSTP-1)) |
  93                                 (1<<(SIGTTIN-1)) | (1<<(SIGTTOU-1)) );
  94         }
  95         if (sig == SIGSTOP || sig == SIGTSTP || sig == SIGTTIN || sig == SIGTTOU)
  96                 p->signal &= ~(1<<(SIGCONT-1));
  97         /* Actually generate the signal */
  98         generate(sig,p);
  99         return 0;
 100 }
 101 
 102 void notify_parent(struct task_struct * tsk)
     /*  */
 103 {
 104         if (tsk->p_pptr == task[smp_num_cpus])          /* Init */
 105                 tsk->exit_signal = SIGCHLD;
 106         send_sig(tsk->exit_signal, tsk->p_pptr, 1);
 107         wake_up_interruptible(&tsk->p_pptr->wait_chldexit);
 108 }
 109 
 110 void release(struct task_struct * p)
     /*  */
 111 {
 112         int i;
 113 
 114         if (!p)
 115                 return;
 116         if (p == current) {
 117                 printk("task releasing itself\n");
 118                 return;
 119         }
 120         for (i=1 ; i<NR_TASKS ; i++)
 121                 if (task[i] == p) {
 122                         nr_tasks--;
 123                         task[i] = NULL;
 124                         REMOVE_LINKS(p);
 125                         release_thread(p);
 126                         if (STACK_MAGIC != *(unsigned long *)p->kernel_stack_page)
 127                                 printk(KERN_ALERT "release: %s kernel stack corruption. Aiee\n", p->comm);
 128                         free_kernel_stack(p->kernel_stack_page);
 129                         current->cmin_flt += p->min_flt + p->cmin_flt;
 130                         current->cmaj_flt += p->maj_flt + p->cmaj_flt;
 131                         current->cnswap += p->nswap + p->cnswap;
 132                         kfree(p);
 133                         return;
 134                 }
 135         panic("trying to release non-existent task");
 136 }
 137 
 138 #ifdef DEBUG_PROC_TREE
 139 /*
 140  * Check to see if a task_struct pointer is present in the task[] array
 141  * Return 0 if found, and 1 if not found.
 142  */
 143 int bad_task_ptr(struct task_struct *p)
     /*  */
 144 {
 145         int     i;
 146 
 147         if (!p)
 148                 return 0;
 149         for (i=0 ; i<NR_TASKS ; i++)
 150                 if (task[i] == p)
 151                         return 0;
 152         return 1;
 153 }
 154         
 155 /*
 156  * This routine scans the pid tree and makes sure the rep invariant still
 157  * holds.  Used for debugging only, since it's very slow....
 158  *
 159  * It looks a lot scarier than it really is.... we're doing nothing more
 160  * than verifying the doubly-linked list found in p_ysptr and p_osptr, 
 161  * and checking it corresponds with the process tree defined by p_cptr and 
 162  * p_pptr;
 163  */
 164 void audit_ptree(void)
     /*  */
 165 {
 166         int     i;
 167 
 168         for (i=1 ; i<NR_TASKS ; i++) {
 169                 if (!task[i])
 170                         continue;
 171                 if (bad_task_ptr(task[i]->p_pptr))
 172                         printk("Warning, pid %d's parent link is bad\n",
 173                                 task[i]->pid);
 174                 if (bad_task_ptr(task[i]->p_cptr))
 175                         printk("Warning, pid %d's child link is bad\n",
 176                                 task[i]->pid);
 177                 if (bad_task_ptr(task[i]->p_ysptr))
 178                         printk("Warning, pid %d's ys link is bad\n",
 179                                 task[i]->pid);
 180                 if (bad_task_ptr(task[i]->p_osptr))
 181                         printk("Warning, pid %d's os link is bad\n",
 182                                 task[i]->pid);
 183                 if (task[i]->p_pptr == task[i])
 184                         printk("Warning, pid %d parent link points to self\n",
 185                                 task[i]->pid);
 186                 if (task[i]->p_cptr == task[i])
 187                         printk("Warning, pid %d child link points to self\n",
 188                                 task[i]->pid);
 189                 if (task[i]->p_ysptr == task[i])
 190                         printk("Warning, pid %d ys link points to self\n",
 191                                 task[i]->pid);
 192                 if (task[i]->p_osptr == task[i])
 193                         printk("Warning, pid %d os link points to self\n",
 194                                 task[i]->pid);
 195                 if (task[i]->p_osptr) {
 196                         if (task[i]->p_pptr != task[i]->p_osptr->p_pptr)
 197                                 printk(
 198                         "Warning, pid %d older sibling %d parent is %d\n",
 199                                 task[i]->pid, task[i]->p_osptr->pid,
 200                                 task[i]->p_osptr->p_pptr->pid);
 201                         if (task[i]->p_osptr->p_ysptr != task[i])
 202                                 printk(
 203                 "Warning, pid %d older sibling %d has mismatched ys link\n",
 204                                 task[i]->pid, task[i]->p_osptr->pid);
 205                 }
 206                 if (task[i]->p_ysptr) {
 207                         if (task[i]->p_pptr != task[i]->p_ysptr->p_pptr)
 208                                 printk(
 209                         "Warning, pid %d younger sibling %d parent is %d\n",
 210                                 task[i]->pid, task[i]->p_osptr->pid,
 211                                 task[i]->p_osptr->p_pptr->pid);
 212                         if (task[i]->p_ysptr->p_osptr != task[i])
 213                                 printk(
 214                 "Warning, pid %d younger sibling %d has mismatched os link\n",
 215                                 task[i]->pid, task[i]->p_ysptr->pid);
 216                 }
 217                 if (task[i]->p_cptr) {
 218                         if (task[i]->p_cptr->p_pptr != task[i])
 219                                 printk(
 220                         "Warning, pid %d youngest child %d has mismatched parent link\n",
 221                                 task[i]->pid, task[i]->p_cptr->pid);
 222                         if (task[i]->p_cptr->p_ysptr)
 223                                 printk(
 224                         "Warning, pid %d youngest child %d has non-NULL ys link\n",
 225                                 task[i]->pid, task[i]->p_cptr->pid);
 226                 }
 227         }
 228 }
 229 #endif /* DEBUG_PROC_TREE */
 230 
 231 /*
 232  * This checks not only the pgrp, but falls back on the pid if no
 233  * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
 234  * without this...
 235  */
 236 int session_of_pgrp(int pgrp)
     /*  */
 237 {
 238         struct task_struct *p;
 239         int fallback;
 240 
 241         fallback = -1;
 242         for_each_task(p) {
 243                 if (p->session <= 0)
 244                         continue;
 245                 if (p->pgrp == pgrp)
 246                         return p->session;
 247                 if (p->pid == pgrp)
 248                         fallback = p->session;
 249         }
 250         return fallback;
 251 }
 252 
 253 /*
 254  * kill_pg() sends a signal to a process group: this is what the tty
 255  * control characters do (^C, ^Z etc)
 256  */
 257 int kill_pg(int pgrp, int sig, int priv)
     /*  */
 258 {
 259         struct task_struct *p;
 260         int err,retval = -ESRCH;
 261         int found = 0;
 262 
 263         if (sig<0 || sig>32 || pgrp<=0)
 264                 return -EINVAL;
 265         for_each_task(p) {
 266                 if (p->pgrp == pgrp) {
 267                         if ((err = send_sig(sig,p,priv)) != 0)
 268                                 retval = err;
 269                         else
 270                                 found++;
 271                 }
 272         }
 273         return(found ? 0 : retval);
 274 }
 275 
 276 /*
 277  * kill_sl() sends a signal to the session leader: this is used
 278  * to send SIGHUP to the controlling process of a terminal when
 279  * the connection is lost.
 280  */
 281 int kill_sl(int sess, int sig, int priv)
     /*  */
 282 {
 283         struct task_struct *p;
 284         int err,retval = -ESRCH;
 285         int found = 0;
 286 
 287         if (sig<0 || sig>32 || sess<=0)
 288                 return -EINVAL;
 289         for_each_task(p) {
 290                 if (p->session == sess && p->leader) {
 291                         if ((err = send_sig(sig,p,priv)) != 0)
 292                                 retval = err;
 293                         else
 294                                 found++;
 295                 }
 296         }
 297         return(found ? 0 : retval);
 298 }
 299 
 300 int kill_proc(int pid, int sig, int priv)
     /*  */
 301 {
 302         struct task_struct *p;
 303 
 304         if (sig<0 || sig>32)
 305                 return -EINVAL;
 306         for_each_task(p) {
 307                 if (p && p->pid == pid)
 308                         return send_sig(sig,p,priv);
 309         }
 310         return(-ESRCH);
 311 }
 312 
 313 /*
 314  * POSIX specifies that kill(-1,sig) is unspecified, but what we have
 315  * is probably wrong.  Should make it like BSD or SYSV.
 316  */
 317 asmlinkage int sys_kill(int pid,int sig)
     /*  */
 318 {
 319         int err, retval = 0, count = 0;
 320 
 321         if (!pid)
 322                 return(kill_pg(current->pgrp,sig,0));
 323         if (pid == -1) {
 324                 struct task_struct * p;
 325                 for_each_task(p) {
 326                         if (p->pid > 1 && p != current) {
 327                                 ++count;
 328                                 if ((err = send_sig(sig,p,0)) != -EPERM)
 329                                         retval = err;
 330                         }
 331                 }
 332                 return(count ? retval : -ESRCH);
 333         }
 334         if (pid < 0) 
 335                 return(kill_pg(-pid,sig,0));
 336         /* Normal kill */
 337         return(kill_proc(pid,sig,0));
 338 }
 339 
 340 /*
 341  * Determine if a process group is "orphaned", according to the POSIX
 342  * definition in 2.2.2.52.  Orphaned process groups are not to be affected
 343  * by terminal-generated stop signals.  Newly orphaned process groups are 
 344  * to receive a SIGHUP and a SIGCONT.
 345  * 
 346  * "I ask you, have you ever known what it is to be an orphan?"
 347  */
 348 int is_orphaned_pgrp(int pgrp)
     /*  */
 349 {
 350         struct task_struct *p;
 351 
 352         for_each_task(p) {
 353                 if ((p->pgrp != pgrp) || 
 354                     (p->state == TASK_ZOMBIE) ||
 355                     (p->p_pptr->pid == 1))
 356                         continue;
 357                 if ((p->p_pptr->pgrp != pgrp) &&
 358                     (p->p_pptr->session == p->session))
 359                         return 0;
 360         }
 361         return(1);      /* (sighing) "Often!" */
 362 }
 363 
 364 static inline int has_stopped_jobs(int pgrp)
     /*  */
 365 {
 366         struct task_struct * p;
 367 
 368         for_each_task(p) {
 369                 if (p->pgrp != pgrp)
 370                         continue;
 371                 if (p->state == TASK_STOPPED)
 372                         return(1);
 373         }
 374         return(0);
 375 }
 376 
 377 static inline void forget_original_parent(struct task_struct * father)
     /*  */
 378 {
 379         struct task_struct * p;
 380 
 381         for_each_task(p) {
 382                 if (p->p_opptr == father)
 383                         if (task[smp_num_cpus]) /* init */
 384                                 p->p_opptr = task[smp_num_cpus];
 385                         else
 386                                 p->p_opptr = task[0];
 387         }
 388 }
 389 
 390 static inline void __exit_files(struct task_struct *tsk)
     /*  */
 391 {
 392         struct files_struct * files = tsk->files;
 393 
 394         if (files) {
 395                 tsk->files = NULL;
 396                 if (!--files->count) {
 397                         int i;
 398                         for (i=0 ; i<NR_OPEN ; i++) {
 399                                 struct file * filp = files->fd[i];
 400                                 if (!filp)
 401                                         continue;
 402                                 files->fd[i] = NULL;
 403                                 close_fp(filp);
 404                         }
 405                         kfree(files);
 406                 }
 407         }
 408 }
 409 
 410 void exit_files(struct task_struct *tsk)
     /*  */
 411 {
 412   __exit_files(tsk);
 413 }
 414 
 415 static inline void __exit_fs(struct task_struct *tsk)
     /*  */
 416 {
 417         struct fs_struct * fs = tsk->fs;
 418 
 419         if (fs) {
 420                 tsk->fs = NULL;
 421                 if (!--fs->count) {
 422                         iput(fs->root);
 423                         iput(fs->pwd);
 424                         kfree(fs);
 425                 }
 426         }
 427 }
 428 
 429 void exit_fs(struct task_struct *tsk)
     /*  */
 430 {
 431   __exit_fs(tsk);
 432 }
 433 
 434 static inline void __exit_sighand(struct task_struct *tsk)
     /*  */
 435 {
 436         struct signal_struct * sig = tsk->sig;
 437 
 438         if (sig) {
 439                 tsk->sig = NULL;
 440                 if (!--sig->count) {
 441                         kfree(sig);
 442                 }
 443         }
 444 }
 445 
 446 void exit_sighand(struct task_struct *tsk)
     /*  */
 447 {
 448         __exit_sighand(tsk);
 449 }
 450 
 451 static inline void __exit_mm(struct task_struct * tsk)
     /*  */
 452 {
 453         struct mm_struct * mm = tsk->mm;
 454 
 455         /* Set us up to use the kernel mm state */
 456         if (mm != &init_mm) {
 457                 flush_cache_mm(mm);
 458                 flush_tlb_mm(mm);
 459                 tsk->mm = &init_mm;
 460                 tsk->swappable = 0;
 461                 SET_PAGE_DIR(tsk, swapper_pg_dir);
 462 
 463                 /* free the old state - not used any more */
 464                 if (!--mm->count) {
 465                         exit_mmap(mm);
 466                         free_page_tables(mm);
 467                         kfree(mm);
 468                 }
 469         }
 470 }
 471 
 472 void exit_mm(struct task_struct *tsk)
     /*  */
 473 {
 474         __exit_mm(tsk);
 475 }
 476 
 477 /* 
 478  * Send signals to all our closest relatives so that they know
 479  * to properly mourn us..
 480  */
 481 static void exit_notify(void)
     /*  */
 482 {
 483         struct task_struct * p;
 484 
 485         forget_original_parent(current);
 486         /* 
 487          * Check to see if any process groups have become orphaned
 488          * as a result of our exiting, and if they have any stopped
 489          * jobs, send them a SIGHUP and then a SIGCONT.  (POSIX 3.2.2.2)
 490          *
 491          * Case i: Our father is in a different pgrp than we are
 492          * and we were the only connection outside, so our pgrp
 493          * is about to become orphaned.
 494          */
 495         if ((current->p_pptr->pgrp != current->pgrp) &&
 496             (current->p_pptr->session == current->session) &&
 497             is_orphaned_pgrp(current->pgrp) &&
 498             has_stopped_jobs(current->pgrp)) {
 499                 kill_pg(current->pgrp,SIGHUP,1);
 500                 kill_pg(current->pgrp,SIGCONT,1);
 501         }
 502         /* Let father know we died */
 503         notify_parent(current);
 504         
 505         /*
 506          * This loop does two things:
 507          * 
 508          * A.  Make init inherit all the child processes
 509          * B.  Check to see if any process groups have become orphaned
 510          *      as a result of our exiting, and if they have any stopped
 511          *      jobs, send them a SIGHUP and then a SIGCONT.  (POSIX 3.2.2.2)
 512          */
 513         while ((p = current->p_cptr) != NULL) {
 514                 current->p_cptr = p->p_osptr;
 515                 p->p_ysptr = NULL;
 516                 p->flags &= ~(PF_PTRACED|PF_TRACESYS);
 517                 if (task[smp_num_cpus] && task[smp_num_cpus] != current) /* init */
 518                         p->p_pptr = task[smp_num_cpus];
 519                 else
 520                         p->p_pptr = task[0];
 521                 p->p_osptr = p->p_pptr->p_cptr;
 522                 p->p_osptr->p_ysptr = p;
 523                 p->p_pptr->p_cptr = p;
 524                 if (p->state == TASK_ZOMBIE)
 525                         notify_parent(p);
 526                 /*
 527                  * process group orphan check
 528                  * Case ii: Our child is in a different pgrp 
 529                  * than we are, and it was the only connection
 530                  * outside, so the child pgrp is now orphaned.
 531                  */
 532                 if ((p->pgrp != current->pgrp) &&
 533                     (p->session == current->session) &&
 534                     is_orphaned_pgrp(p->pgrp) &&
 535                     has_stopped_jobs(p->pgrp)) {
 536                         kill_pg(p->pgrp,SIGHUP,1);
 537                         kill_pg(p->pgrp,SIGCONT,1);
 538                 }
 539         }
 540         if (current->leader)
 541                 disassociate_ctty(1);
 542 }
 543 
 544 NORET_TYPE void do_exit(long code)
     /*  */
 545 {
 546         if (intr_count) {
 547                 printk("Aiee, killing interrupt handler\n");
 548                 intr_count = 0;
 549         }
 550 fake_volatile:
 551         acct_process(code);
 552         current->flags |= PF_EXITING;
 553         del_timer(&current->real_timer);
 554         sem_exit();
 555         kerneld_exit();
 556         __exit_mm(current);
 557         __exit_files(current);
 558         __exit_fs(current);
 559         __exit_sighand(current);
 560         exit_thread();
 561         current->state = TASK_ZOMBIE;
 562         current->exit_code = code;
 563         exit_notify();
 564 #ifdef DEBUG_PROC_TREE
 565         audit_ptree();
 566 #endif
 567         if (current->exec_domain && current->exec_domain->use_count)
 568                 (*current->exec_domain->use_count)--;
 569         if (current->binfmt && current->binfmt->use_count)
 570                 (*current->binfmt->use_count)--;
 571         schedule();
 572 /*
 573  * In order to get rid of the "volatile function does return" message
 574  * I did this little loop that confuses gcc to think do_exit really
 575  * is volatile. In fact it's schedule() that is volatile in some
 576  * circumstances: when current->state = ZOMBIE, schedule() never
 577  * returns.
 578  *
 579  * In fact the natural way to do all this is to have the label and the
 580  * goto right after each other, but I put the fake_volatile label at
 581  * the start of the function just in case something /really/ bad
 582  * happens, and the schedule returns. This way we can try again. I'm
 583  * not paranoid: it's just that everybody is out to get me.
 584  */
 585         goto fake_volatile;
 586 }
 587 
 588 asmlinkage int sys_exit(int error_code)
     /*  */
 589 {
 590         do_exit((error_code&0xff)<<8);
 591 }
 592 
 593 asmlinkage int sys_wait4(pid_t pid,unsigned int * stat_addr, int options, struct rusage * ru)
     /*  */
 594 {
 595         int flag, retval;
 596         struct wait_queue wait = { current, NULL };
 597         struct task_struct *p;
 598 
 599         if (stat_addr) {
 600                 flag = verify_area(VERIFY_WRITE, stat_addr, sizeof(*stat_addr));
 601                 if (flag)
 602                         return flag;
 603         }
 604         if (ru) {
 605                 flag = verify_area(VERIFY_WRITE, ru, sizeof(*ru));
 606                 if (flag)
 607                         return flag;
 608         }
 609         add_wait_queue(&current->wait_chldexit,&wait);
 610 repeat:
 611         flag=0;
 612         for (p = current->p_cptr ; p ; p = p->p_osptr) {
 613                 if (pid>0) {
 614                         if (p->pid != pid)
 615                                 continue;
 616                 } else if (!pid) {
 617                         if (p->pgrp != current->pgrp)
 618                                 continue;
 619                 } else if (pid != -1) {
 620                         if (p->pgrp != -pid)
 621                                 continue;
 622                 }
 623                 /* wait for cloned processes iff the __WCLONE flag is set */
 624                 if ((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
 625                         continue;
 626                 flag = 1;
 627                 switch (p->state) {
 628                         case TASK_STOPPED:
 629                                 if (!p->exit_code)
 630                                         continue;
 631                                 if (!(options & WUNTRACED) && !(p->flags & PF_PTRACED))
 632                                         continue;
 633                                 if (ru != NULL)
 634                                         getrusage(p, RUSAGE_BOTH, ru);
 635                                 if (stat_addr)
 636                                         put_user((p->exit_code << 8) | 0x7f,
 637                                                 stat_addr);
 638                                 p->exit_code = 0;
 639                                 retval = p->pid;
 640                                 goto end_wait4;
 641                         case TASK_ZOMBIE:
 642                                 current->cutime += p->utime + p->cutime;
 643                                 current->cstime += p->stime + p->cstime;
 644                                 if (ru != NULL)
 645                                         getrusage(p, RUSAGE_BOTH, ru);
 646                                 if (stat_addr)
 647                                         put_user(p->exit_code, stat_addr);
 648                                 retval = p->pid;
 649                                 if (p->p_opptr != p->p_pptr) {
 650                                         REMOVE_LINKS(p);
 651                                         p->p_pptr = p->p_opptr;
 652                                         SET_LINKS(p);
 653                                         notify_parent(p);
 654                                 } else
 655                                         release(p);
 656 #ifdef DEBUG_PROC_TREE
 657                                 audit_ptree();
 658 #endif
 659                                 goto end_wait4;
 660                         default:
 661                                 continue;
 662                 }
 663         }
 664         if (flag) {
 665                 retval = 0;
 666                 if (options & WNOHANG)
 667                         goto end_wait4;
 668                 current->state=TASK_INTERRUPTIBLE;
 669                 schedule();
 670                 current->signal &= ~(1<<(SIGCHLD-1));
 671                 retval = -ERESTARTSYS;
 672                 if (current->signal & ~current->blocked)
 673                         goto end_wait4;
 674                 goto repeat;
 675         }
 676         retval = -ECHILD;
 677 end_wait4:
 678         remove_wait_queue(&current->wait_chldexit,&wait);
 679         return retval;
 680 }
 681 
 682 #ifndef __alpha__
 683 
 684 /*
 685  * sys_waitpid() remains for compatibility. waitpid() should be
 686  * implemented by calling sys_wait4() from libc.a.
 687  */
 688 asmlinkage int sys_waitpid(pid_t pid,unsigned int * stat_addr, int options)
     /*  */
 689 {
 690         return sys_wait4(pid, stat_addr, options, NULL);
 691 }
 692 
 693 #endif
/* */
root/kernel/exit.c

DEFINITIONS
