root/include/linux/sched/signal.h

INCLUDED FROM

DEFINITIONS

1. signal_set_stop_flags
2. signal_group_exit
3. kernel_dequeue_signal
4. kernel_signal_stop
5. restart_syscall
6. signal_pending
7. __fatal_signal_pending
8. fatal_signal_pending
9. signal_pending_state
10. signal_wake_up
11. ptrace_signal_wake_up
12. set_restore_sigmask
13. clear_tsk_restore_sigmask
14. clear_restore_sigmask
15. test_tsk_restore_sigmask
16. test_restore_sigmask
17. test_and_clear_restore_sigmask
18. set_restore_sigmask
19. clear_tsk_restore_sigmask
20. clear_restore_sigmask
21. test_restore_sigmask
22. test_tsk_restore_sigmask
23. test_and_clear_restore_sigmask
24. restore_saved_sigmask
25. restore_saved_sigmask_unless
26. sigmask_to_save
27. kill_cad_pid
28. sas_ss_flags
29. sas_ss_reset
30. sigsp
31. task_pid_type
32. task_tgid
33. task_pgrp
34. task_session
35. get_nr_threads
36. thread_group_leader
37. has_group_leader_pid
38. same_thread_group
39. next_thread
40. thread_group_empty
41. lock_task_sighand
42. unlock_task_sighand
43. task_rlimit
44. task_rlimit_max
45. rlimit
46. rlimit_max

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_SCHED_SIGNAL_H
   3 #define _LINUX_SCHED_SIGNAL_H
   4 
   5 #include <linux/rculist.h>
   6 #include <linux/signal.h>
   7 #include <linux/sched.h>
   8 #include <linux/sched/jobctl.h>
   9 #include <linux/sched/task.h>
  10 #include <linux/cred.h>
  11 #include <linux/refcount.h>
  12 #include <linux/posix-timers.h>
  13 
  14 /*
  15  * Types defining task->signal and task->sighand and APIs using them:
  16  */
  17 
  18 struct sighand_struct {
  19         spinlock_t              siglock;
  20         refcount_t              count;
  21         wait_queue_head_t       signalfd_wqh;
  22         struct k_sigaction      action[_NSIG];
  23 };
  24 
  25 /*
  26  * Per-process accounting stats:
  27  */
  28 struct pacct_struct {
  29         int                     ac_flag;
  30         long                    ac_exitcode;
  31         unsigned long           ac_mem;
  32         u64                     ac_utime, ac_stime;
  33         unsigned long           ac_minflt, ac_majflt;
  34 };
  35 
  36 struct cpu_itimer {
  37         u64 expires;
  38         u64 incr;
  39 };
  40 
  41 /*
  42  * This is the atomic variant of task_cputime, which can be used for
  43  * storing and updating task_cputime statistics without locking.
  44  */
  45 struct task_cputime_atomic {
  46         atomic64_t utime;
  47         atomic64_t stime;
  48         atomic64_t sum_exec_runtime;
  49 };
  50 
  51 #define INIT_CPUTIME_ATOMIC \
  52         (struct task_cputime_atomic) {                          \
  53                 .utime = ATOMIC64_INIT(0),                      \
  54                 .stime = ATOMIC64_INIT(0),                      \
  55                 .sum_exec_runtime = ATOMIC64_INIT(0),           \
  56         }
  57 /**
  58  * struct thread_group_cputimer - thread group interval timer counts
  59  * @cputime_atomic:     atomic thread group interval timers.
  60  *
  61  * This structure contains the version of task_cputime, above, that is
  62  * used for thread group CPU timer calculations.
  63  */
  64 struct thread_group_cputimer {
  65         struct task_cputime_atomic cputime_atomic;
  66 };
  67 
  68 struct multiprocess_signals {
  69         sigset_t signal;
  70         struct hlist_node node;
  71 };
  72 
  73 /*
  74  * NOTE! "signal_struct" does not have its own
  75  * locking, because a shared signal_struct always
  76  * implies a shared sighand_struct, so locking
  77  * sighand_struct is always a proper superset of
  78  * the locking of signal_struct.
  79  */
  80 struct signal_struct {
  81         refcount_t              sigcnt;
  82         atomic_t                live;
  83         int                     nr_threads;
  84         struct list_head        thread_head;
  85 
  86         wait_queue_head_t       wait_chldexit;  /* for wait4() */
  87 
  88         /* current thread group signal load-balancing target: */
  89         struct task_struct      *curr_target;
  90 
  91         /* shared signal handling: */
  92         struct sigpending       shared_pending;
  93 
  94         /* For collecting multiprocess signals during fork */
  95         struct hlist_head       multiprocess;
  96 
  97         /* thread group exit support */
  98         int                     group_exit_code;
  99         /* overloaded:
 100          * - notify group_exit_task when ->count is equal to notify_count
 101          * - everyone except group_exit_task is stopped during signal delivery
 102          *   of fatal signals, group_exit_task processes the signal.
 103          */
 104         int                     notify_count;
 105         struct task_struct      *group_exit_task;
 106 
 107         /* thread group stop support, overloads group_exit_code too */
 108         int                     group_stop_count;
 109         unsigned int            flags; /* see SIGNAL_* flags below */
 110 
 111         /*
 112          * PR_SET_CHILD_SUBREAPER marks a process, like a service
 113          * manager, to re-parent orphan (double-forking) child processes
 114          * to this process instead of 'init'. The service manager is
 115          * able to receive SIGCHLD signals and is able to investigate
 116          * the process until it calls wait(). All children of this
 117          * process will inherit a flag if they should look for a
 118          * child_subreaper process at exit.
 119          */
 120         unsigned int            is_child_subreaper:1;
 121         unsigned int            has_child_subreaper:1;
 122 
 123 #ifdef CONFIG_POSIX_TIMERS
 124 
 125         /* POSIX.1b Interval Timers */
 126         int                     posix_timer_id;
 127         struct list_head        posix_timers;
 128 
 129         /* ITIMER_REAL timer for the process */
 130         struct hrtimer real_timer;
 131         ktime_t it_real_incr;
 132 
 133         /*
 134          * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
 135          * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
 136          * values are defined to 0 and 1 respectively
 137          */
 138         struct cpu_itimer it[2];
 139 
 140         /*
 141          * Thread group totals for process CPU timers.
 142          * See thread_group_cputimer(), et al, for details.
 143          */
 144         struct thread_group_cputimer cputimer;
 145 
 146 #endif
 147         /* Empty if CONFIG_POSIX_TIMERS=n */
 148         struct posix_cputimers posix_cputimers;
 149 
 150         /* PID/PID hash table linkage. */
 151         struct pid *pids[PIDTYPE_MAX];
 152 
 153 #ifdef CONFIG_NO_HZ_FULL
 154         atomic_t tick_dep_mask;
 155 #endif
 156 
 157         struct pid *tty_old_pgrp;
 158 
 159         /* boolean value for session group leader */
 160         int leader;
 161 
 162         struct tty_struct *tty; /* NULL if no tty */
 163 
 164 #ifdef CONFIG_SCHED_AUTOGROUP
 165         struct autogroup *autogroup;
 166 #endif
 167         /*
 168          * Cumulative resource counters for dead threads in the group,
 169          * and for reaped dead child processes forked by this group.
 170          * Live threads maintain their own counters and add to these
 171          * in __exit_signal, except for the group leader.
 172          */
 173         seqlock_t stats_lock;
 174         u64 utime, stime, cutime, cstime;
 175         u64 gtime;
 176         u64 cgtime;
 177         struct prev_cputime prev_cputime;
 178         unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
 179         unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
 180         unsigned long inblock, oublock, cinblock, coublock;
 181         unsigned long maxrss, cmaxrss;
 182         struct task_io_accounting ioac;
 183 
 184         /*
 185          * Cumulative ns of schedule CPU time fo dead threads in the
 186          * group, not including a zombie group leader, (This only differs
 187          * from jiffies_to_ns(utime + stime) if sched_clock uses something
 188          * other than jiffies.)
 189          */
 190         unsigned long long sum_sched_runtime;
 191 
 192         /*
 193          * We don't bother to synchronize most readers of this at all,
 194          * because there is no reader checking a limit that actually needs
 195          * to get both rlim_cur and rlim_max atomically, and either one
 196          * alone is a single word that can safely be read normally.
 197          * getrlimit/setrlimit use task_lock(current->group_leader) to
 198          * protect this instead of the siglock, because they really
 199          * have no need to disable irqs.
 200          */
 201         struct rlimit rlim[RLIM_NLIMITS];
 202 
 203 #ifdef CONFIG_BSD_PROCESS_ACCT
 204         struct pacct_struct pacct;      /* per-process accounting information */
 205 #endif
 206 #ifdef CONFIG_TASKSTATS
 207         struct taskstats *stats;
 208 #endif
 209 #ifdef CONFIG_AUDIT
 210         unsigned audit_tty;
 211         struct tty_audit_buf *tty_audit_buf;
 212 #endif
 213 
 214         /*
 215          * Thread is the potential origin of an oom condition; kill first on
 216          * oom
 217          */
 218         bool oom_flag_origin;
 219         short oom_score_adj;            /* OOM kill score adjustment */
 220         short oom_score_adj_min;        /* OOM kill score adjustment min value.
 221                                          * Only settable by CAP_SYS_RESOURCE. */
 222         struct mm_struct *oom_mm;       /* recorded mm when the thread group got
 223                                          * killed by the oom killer */
 224 
 225         struct mutex cred_guard_mutex;  /* guard against foreign influences on
 226                                          * credential calculations
 227                                          * (notably. ptrace) */
 228 } __randomize_layout;
 229 
 230 /*
 231  * Bits in flags field of signal_struct.
 232  */
 233 #define SIGNAL_STOP_STOPPED     0x00000001 /* job control stop in effect */
 234 #define SIGNAL_STOP_CONTINUED   0x00000002 /* SIGCONT since WCONTINUED reap */
 235 #define SIGNAL_GROUP_EXIT       0x00000004 /* group exit in progress */
 236 #define SIGNAL_GROUP_COREDUMP   0x00000008 /* coredump in progress */
 237 /*
 238  * Pending notifications to parent.
 239  */
 240 #define SIGNAL_CLD_STOPPED      0x00000010
 241 #define SIGNAL_CLD_CONTINUED    0x00000020
 242 #define SIGNAL_CLD_MASK         (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
 243 
 244 #define SIGNAL_UNKILLABLE       0x00000040 /* for init: ignore fatal signals */
 245 
 246 #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
 247                           SIGNAL_STOP_CONTINUED)
 248 
 249 static inline void signal_set_stop_flags(struct signal_struct *sig,
 250                                          unsigned int flags)
 251 {
 252         WARN_ON(sig->flags & (SIGNAL_GROUP_EXIT|SIGNAL_GROUP_COREDUMP));
 253         sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
 254 }
 255 
 256 /* If true, all threads except ->group_exit_task have pending SIGKILL */
 257 static inline int signal_group_exit(const struct signal_struct *sig)
 258 {
 259         return  (sig->flags & SIGNAL_GROUP_EXIT) ||
 260                 (sig->group_exit_task != NULL);
 261 }
 262 
 263 extern void flush_signals(struct task_struct *);
 264 extern void ignore_signals(struct task_struct *);
 265 extern void flush_signal_handlers(struct task_struct *, int force_default);
 266 extern int dequeue_signal(struct task_struct *task,
 267                           sigset_t *mask, kernel_siginfo_t *info);
 268 
 269 static inline int kernel_dequeue_signal(void)
 270 {
 271         struct task_struct *task = current;
 272         kernel_siginfo_t __info;
 273         int ret;
 274 
 275         spin_lock_irq(&task->sighand->siglock);
 276         ret = dequeue_signal(task, &task->blocked, &__info);
 277         spin_unlock_irq(&task->sighand->siglock);
 278 
 279         return ret;
 280 }
 281 
 282 static inline void kernel_signal_stop(void)
 283 {
 284         spin_lock_irq(&current->sighand->siglock);
 285         if (current->jobctl & JOBCTL_STOP_DEQUEUED)
 286                 set_special_state(TASK_STOPPED);
 287         spin_unlock_irq(&current->sighand->siglock);
 288 
 289         schedule();
 290 }
 291 #ifdef __ARCH_SI_TRAPNO
 292 # define ___ARCH_SI_TRAPNO(_a1) , _a1
 293 #else
 294 # define ___ARCH_SI_TRAPNO(_a1)
 295 #endif
 296 #ifdef __ia64__
 297 # define ___ARCH_SI_IA64(_a1, _a2, _a3) , _a1, _a2, _a3
 298 #else
 299 # define ___ARCH_SI_IA64(_a1, _a2, _a3)
 300 #endif
 301 
 302 int force_sig_fault_to_task(int sig, int code, void __user *addr
 303         ___ARCH_SI_TRAPNO(int trapno)
 304         ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
 305         , struct task_struct *t);
 306 int force_sig_fault(int sig, int code, void __user *addr
 307         ___ARCH_SI_TRAPNO(int trapno)
 308         ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr));
 309 int send_sig_fault(int sig, int code, void __user *addr
 310         ___ARCH_SI_TRAPNO(int trapno)
 311         ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
 312         , struct task_struct *t);
 313 
 314 int force_sig_mceerr(int code, void __user *, short);
 315 int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
 316 
 317 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
 318 int force_sig_pkuerr(void __user *addr, u32 pkey);
 319 
 320 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
 321 
 322 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
 323 extern void force_sigsegv(int sig);
 324 extern int force_sig_info(struct kernel_siginfo *);
 325 extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
 326 extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
 327 extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
 328                                 const struct cred *);
 329 extern int kill_pgrp(struct pid *pid, int sig, int priv);
 330 extern int kill_pid(struct pid *pid, int sig, int priv);
 331 extern __must_check bool do_notify_parent(struct task_struct *, int);
 332 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
 333 extern void force_sig(int);
 334 extern int send_sig(int, struct task_struct *, int);
 335 extern int zap_other_threads(struct task_struct *p);
 336 extern struct sigqueue *sigqueue_alloc(void);
 337 extern void sigqueue_free(struct sigqueue *);
 338 extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
 339 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
 340 
 341 static inline int restart_syscall(void)
 342 {
 343         set_tsk_thread_flag(current, TIF_SIGPENDING);
 344         return -ERESTARTNOINTR;
 345 }
 346 
 347 static inline int signal_pending(struct task_struct *p)
 348 {
 349         return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
 350 }
 351 
 352 static inline int __fatal_signal_pending(struct task_struct *p)
 353 {
 354         return unlikely(sigismember(&p->pending.signal, SIGKILL));
 355 }
 356 
 357 static inline int fatal_signal_pending(struct task_struct *p)
 358 {
 359         return signal_pending(p) && __fatal_signal_pending(p);
 360 }
 361 
 362 static inline int signal_pending_state(long state, struct task_struct *p)
 363 {
 364         if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
 365                 return 0;
 366         if (!signal_pending(p))
 367                 return 0;
 368 
 369         return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
 370 }
 371 
 372 /*
 373  * Reevaluate whether the task has signals pending delivery.
 374  * Wake the task if so.
 375  * This is required every time the blocked sigset_t changes.
 376  * callers must hold sighand->siglock.
 377  */
 378 extern void recalc_sigpending_and_wake(struct task_struct *t);
 379 extern void recalc_sigpending(void);
 380 extern void calculate_sigpending(void);
 381 
 382 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
 383 
 384 static inline void signal_wake_up(struct task_struct *t, bool resume)
 385 {
 386         signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
 387 }
 388 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
 389 {
 390         signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
 391 }
 392 
 393 void task_join_group_stop(struct task_struct *task);
 394 
 395 #ifdef TIF_RESTORE_SIGMASK
 396 /*
 397  * Legacy restore_sigmask accessors.  These are inefficient on
 398  * SMP architectures because they require atomic operations.
 399  */
 400 
 401 /**
 402  * set_restore_sigmask() - make sure saved_sigmask processing gets done
 403  *
 404  * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
 405  * will run before returning to user mode, to process the flag.  For
 406  * all callers, TIF_SIGPENDING is already set or it's no harm to set
 407  * it.  TIF_RESTORE_SIGMASK need not be in the set of bits that the
 408  * arch code will notice on return to user mode, in case those bits
 409  * are scarce.  We set TIF_SIGPENDING here to ensure that the arch
 410  * signal code always gets run when TIF_RESTORE_SIGMASK is set.
 411  */
 412 static inline void set_restore_sigmask(void)
 413 {
 414         set_thread_flag(TIF_RESTORE_SIGMASK);
 415 }
 416 
 417 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
 418 {
 419         clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
 420 }
 421 
 422 static inline void clear_restore_sigmask(void)
 423 {
 424         clear_thread_flag(TIF_RESTORE_SIGMASK);
 425 }
 426 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
 427 {
 428         return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
 429 }
 430 static inline bool test_restore_sigmask(void)
 431 {
 432         return test_thread_flag(TIF_RESTORE_SIGMASK);
 433 }
 434 static inline bool test_and_clear_restore_sigmask(void)
 435 {
 436         return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
 437 }
 438 
 439 #else   /* TIF_RESTORE_SIGMASK */
 440 
 441 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
 442 static inline void set_restore_sigmask(void)
 443 {
 444         current->restore_sigmask = true;
 445 }
 446 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
 447 {
 448         task->restore_sigmask = false;
 449 }
 450 static inline void clear_restore_sigmask(void)
 451 {
 452         current->restore_sigmask = false;
 453 }
 454 static inline bool test_restore_sigmask(void)
 455 {
 456         return current->restore_sigmask;
 457 }
 458 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
 459 {
 460         return task->restore_sigmask;
 461 }
 462 static inline bool test_and_clear_restore_sigmask(void)
 463 {
 464         if (!current->restore_sigmask)
 465                 return false;
 466         current->restore_sigmask = false;
 467         return true;
 468 }
 469 #endif
 470 
 471 static inline void restore_saved_sigmask(void)
 472 {
 473         if (test_and_clear_restore_sigmask())
 474                 __set_current_blocked(&current->saved_sigmask);
 475 }
 476 
 477 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
 478 
 479 static inline void restore_saved_sigmask_unless(bool interrupted)
 480 {
 481         if (interrupted)
 482                 WARN_ON(!test_thread_flag(TIF_SIGPENDING));
 483         else
 484                 restore_saved_sigmask();
 485 }
 486 
 487 static inline sigset_t *sigmask_to_save(void)
 488 {
 489         sigset_t *res = &current->blocked;
 490         if (unlikely(test_restore_sigmask()))
 491                 res = &current->saved_sigmask;
 492         return res;
 493 }
 494 
 495 static inline int kill_cad_pid(int sig, int priv)
 496 {
 497         return kill_pid(cad_pid, sig, priv);
 498 }
 499 
 500 /* These can be the second arg to send_sig_info/send_group_sig_info.  */
 501 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
 502 #define SEND_SIG_PRIV   ((struct kernel_siginfo *) 1)
 503 
 504 /*
 505  * True if we are on the alternate signal stack.
 506  */
 507 static inline int on_sig_stack(unsigned long sp)
 508 {
 509         /*
 510          * If the signal stack is SS_AUTODISARM then, by construction, we
 511          * can't be on the signal stack unless user code deliberately set
 512          * SS_AUTODISARM when we were already on it.
 513          *
 514          * This improves reliability: if user state gets corrupted such that
 515          * the stack pointer points very close to the end of the signal stack,
 516          * then this check will enable the signal to be handled anyway.
 517          */
 518         if (current->sas_ss_flags & SS_AUTODISARM)
 519                 return 0;
 520 
 521 #ifdef CONFIG_STACK_GROWSUP
 522         return sp >= current->sas_ss_sp &&
 523                 sp - current->sas_ss_sp < current->sas_ss_size;
 524 #else
 525         return sp > current->sas_ss_sp &&
 526                 sp - current->sas_ss_sp <= current->sas_ss_size;
 527 #endif
 528 }
 529 
 530 static inline int sas_ss_flags(unsigned long sp)
 531 {
 532         if (!current->sas_ss_size)
 533                 return SS_DISABLE;
 534 
 535         return on_sig_stack(sp) ? SS_ONSTACK : 0;
 536 }
 537 
 538 static inline void sas_ss_reset(struct task_struct *p)
 539 {
 540         p->sas_ss_sp = 0;
 541         p->sas_ss_size = 0;
 542         p->sas_ss_flags = SS_DISABLE;
 543 }
 544 
 545 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
 546 {
 547         if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
 548 #ifdef CONFIG_STACK_GROWSUP
 549                 return current->sas_ss_sp;
 550 #else
 551                 return current->sas_ss_sp + current->sas_ss_size;
 552 #endif
 553         return sp;
 554 }
 555 
 556 extern void __cleanup_sighand(struct sighand_struct *);
 557 extern void flush_itimer_signals(void);
 558 
 559 #define tasklist_empty() \
 560         list_empty(&init_task.tasks)
 561 
 562 #define next_task(p) \
 563         list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
 564 
 565 #define for_each_process(p) \
 566         for (p = &init_task ; (p = next_task(p)) != &init_task ; )
 567 
 568 extern bool current_is_single_threaded(void);
 569 
 570 /*
 571  * Careful: do_each_thread/while_each_thread is a double loop so
 572  *          'break' will not work as expected - use goto instead.
 573  */
 574 #define do_each_thread(g, t) \
 575         for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
 576 
 577 #define while_each_thread(g, t) \
 578         while ((t = next_thread(t)) != g)
 579 
 580 #define __for_each_thread(signal, t)    \
 581         list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)
 582 
 583 #define for_each_thread(p, t)           \
 584         __for_each_thread((p)->signal, t)
 585 
 586 /* Careful: this is a double loop, 'break' won't work as expected. */
 587 #define for_each_process_thread(p, t)   \
 588         for_each_process(p) for_each_thread(p, t)
 589 
 590 typedef int (*proc_visitor)(struct task_struct *p, void *data);
 591 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
 592 
 593 static inline
 594 struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
 595 {
 596         struct pid *pid;
 597         if (type == PIDTYPE_PID)
 598                 pid = task_pid(task);
 599         else
 600                 pid = task->signal->pids[type];
 601         return pid;
 602 }
 603 
 604 static inline struct pid *task_tgid(struct task_struct *task)
 605 {
 606         return task->signal->pids[PIDTYPE_TGID];
 607 }
 608 
 609 /*
 610  * Without tasklist or RCU lock it is not safe to dereference
 611  * the result of task_pgrp/task_session even if task == current,
 612  * we can race with another thread doing sys_setsid/sys_setpgid.
 613  */
 614 static inline struct pid *task_pgrp(struct task_struct *task)
 615 {
 616         return task->signal->pids[PIDTYPE_PGID];
 617 }
 618 
 619 static inline struct pid *task_session(struct task_struct *task)
 620 {
 621         return task->signal->pids[PIDTYPE_SID];
 622 }
 623 
 624 static inline int get_nr_threads(struct task_struct *task)
 625 {
 626         return task->signal->nr_threads;
 627 }
 628 
 629 static inline bool thread_group_leader(struct task_struct *p)
 630 {
 631         return p->exit_signal >= 0;
 632 }
 633 
 634 /* Do to the insanities of de_thread it is possible for a process
 635  * to have the pid of the thread group leader without actually being
 636  * the thread group leader.  For iteration through the pids in proc
 637  * all we care about is that we have a task with the appropriate
 638  * pid, we don't actually care if we have the right task.
 639  */
 640 static inline bool has_group_leader_pid(struct task_struct *p)
 641 {
 642         return task_pid(p) == task_tgid(p);
 643 }
 644 
 645 static inline
 646 bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
 647 {
 648         return p1->signal == p2->signal;
 649 }
 650 
 651 static inline struct task_struct *next_thread(const struct task_struct *p)
 652 {
 653         return list_entry_rcu(p->thread_group.next,
 654                               struct task_struct, thread_group);
 655 }
 656 
 657 static inline int thread_group_empty(struct task_struct *p)
 658 {
 659         return list_empty(&p->thread_group);
 660 }
 661 
 662 #define delay_group_leader(p) \
 663                 (thread_group_leader(p) && !thread_group_empty(p))
 664 
 665 extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
 666                                                         unsigned long *flags);
 667 
 668 static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
 669                                                        unsigned long *flags)
 670 {
 671         struct sighand_struct *ret;
 672 
 673         ret = __lock_task_sighand(task, flags);
 674         (void)__cond_lock(&task->sighand->siglock, ret);
 675         return ret;
 676 }
 677 
 678 static inline void unlock_task_sighand(struct task_struct *task,
 679                                                 unsigned long *flags)
 680 {
 681         spin_unlock_irqrestore(&task->sighand->siglock, *flags);
 682 }
 683 
 684 static inline unsigned long task_rlimit(const struct task_struct *task,
 685                 unsigned int limit)
 686 {
 687         return READ_ONCE(task->signal->rlim[limit].rlim_cur);
 688 }
 689 
 690 static inline unsigned long task_rlimit_max(const struct task_struct *task,
 691                 unsigned int limit)
 692 {
 693         return READ_ONCE(task->signal->rlim[limit].rlim_max);
 694 }
 695 
 696 static inline unsigned long rlimit(unsigned int limit)
 697 {
 698         return task_rlimit(current, limit);
 699 }
 700 
 701 static inline unsigned long rlimit_max(unsigned int limit)
 702 {
 703         return task_rlimit_max(current, limit);
 704 }
 705 
 706 #endif /* _LINUX_SCHED_SIGNAL_H */