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TOMOYO Linux Cross Reference
Linux/include/linux/sched/signal.h

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  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 #include <linux/mm_types.h>
 14 #include <asm/ptrace.h>
 15 
 16 /*
 17  * Types defining task->signal and task->sighand and APIs using them:
 18  */
 19 
 20 struct sighand_struct {
 21         spinlock_t              siglock;
 22         refcount_t              count;
 23         wait_queue_head_t       signalfd_wqh;
 24         struct k_sigaction      action[_NSIG];
 25 };
 26 
 27 /*
 28  * Per-process accounting stats:
 29  */
 30 struct pacct_struct {
 31         int                     ac_flag;
 32         long                    ac_exitcode;
 33         unsigned long           ac_mem;
 34         u64                     ac_utime, ac_stime;
 35         unsigned long           ac_minflt, ac_majflt;
 36 };
 37 
 38 struct cpu_itimer {
 39         u64 expires;
 40         u64 incr;
 41 };
 42 
 43 /*
 44  * This is the atomic variant of task_cputime, which can be used for
 45  * storing and updating task_cputime statistics without locking.
 46  */
 47 struct task_cputime_atomic {
 48         atomic64_t utime;
 49         atomic64_t stime;
 50         atomic64_t sum_exec_runtime;
 51 };
 52 
 53 #define INIT_CPUTIME_ATOMIC \
 54         (struct task_cputime_atomic) {                          \
 55                 .utime = ATOMIC64_INIT(0),                      \
 56                 .stime = ATOMIC64_INIT(0),                      \
 57                 .sum_exec_runtime = ATOMIC64_INIT(0),           \
 58         }
 59 /**
 60  * struct thread_group_cputimer - thread group interval timer counts
 61  * @cputime_atomic:     atomic thread group interval timers.
 62  *
 63  * This structure contains the version of task_cputime, above, that is
 64  * used for thread group CPU timer calculations.
 65  */
 66 struct thread_group_cputimer {
 67         struct task_cputime_atomic cputime_atomic;
 68 };
 69 
 70 struct multiprocess_signals {
 71         sigset_t signal;
 72         struct hlist_node node;
 73 };
 74 
 75 /*
 76  * NOTE! "signal_struct" does not have its own
 77  * locking, because a shared signal_struct always
 78  * implies a shared sighand_struct, so locking
 79  * sighand_struct is always a proper superset of
 80  * the locking of signal_struct.
 81  */
 82 struct signal_struct {
 83         refcount_t              sigcnt;
 84         atomic_t                live;
 85         int                     nr_threads;
 86         struct list_head        thread_head;
 87 
 88         wait_queue_head_t       wait_chldexit;  /* for wait4() */
 89 
 90         /* current thread group signal load-balancing target: */
 91         struct task_struct      *curr_target;
 92 
 93         /* shared signal handling: */
 94         struct sigpending       shared_pending;
 95 
 96         /* For collecting multiprocess signals during fork */
 97         struct hlist_head       multiprocess;
 98 
 99         /* thread group exit support */
100         int                     group_exit_code;
101         /* overloaded:
102          * - notify group_exit_task when ->count is equal to notify_count
103          * - everyone except group_exit_task is stopped during signal delivery
104          *   of fatal signals, group_exit_task processes the signal.
105          */
106         int                     notify_count;
107         struct task_struct      *group_exit_task;
108 
109         /* thread group stop support, overloads group_exit_code too */
110         int                     group_stop_count;
111         unsigned int            flags; /* see SIGNAL_* flags below */
112 
113         /*
114          * PR_SET_CHILD_SUBREAPER marks a process, like a service
115          * manager, to re-parent orphan (double-forking) child processes
116          * to this process instead of 'init'. The service manager is
117          * able to receive SIGCHLD signals and is able to investigate
118          * the process until it calls wait(). All children of this
119          * process will inherit a flag if they should look for a
120          * child_subreaper process at exit.
121          */
122         unsigned int            is_child_subreaper:1;
123         unsigned int            has_child_subreaper:1;
124 
125 #ifdef CONFIG_POSIX_TIMERS
126 
127         /* POSIX.1b Interval Timers */
128         int                     posix_timer_id;
129         struct list_head        posix_timers;
130 
131         /* ITIMER_REAL timer for the process */
132         struct hrtimer real_timer;
133         ktime_t it_real_incr;
134 
135         /*
136          * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
137          * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
138          * values are defined to 0 and 1 respectively
139          */
140         struct cpu_itimer it[2];
141 
142         /*
143          * Thread group totals for process CPU timers.
144          * See thread_group_cputimer(), et al, for details.
145          */
146         struct thread_group_cputimer cputimer;
147 
148 #endif
149         /* Empty if CONFIG_POSIX_TIMERS=n */
150         struct posix_cputimers posix_cputimers;
151 
152         /* PID/PID hash table linkage. */
153         struct pid *pids[PIDTYPE_MAX];
154 
155 #ifdef CONFIG_NO_HZ_FULL
156         atomic_t tick_dep_mask;
157 #endif
158 
159         struct pid *tty_old_pgrp;
160 
161         /* boolean value for session group leader */
162         int leader;
163 
164         struct tty_struct *tty; /* NULL if no tty */
165 
166 #ifdef CONFIG_SCHED_AUTOGROUP
167         struct autogroup *autogroup;
168 #endif
169         /*
170          * Cumulative resource counters for dead threads in the group,
171          * and for reaped dead child processes forked by this group.
172          * Live threads maintain their own counters and add to these
173          * in __exit_signal, except for the group leader.
174          */
175         seqlock_t stats_lock;
176         u64 utime, stime, cutime, cstime;
177         u64 gtime;
178         u64 cgtime;
179         struct prev_cputime prev_cputime;
180         unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
181         unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
182         unsigned long inblock, oublock, cinblock, coublock;
183         unsigned long maxrss, cmaxrss;
184         struct task_io_accounting ioac;
185 
186         /*
187          * Cumulative ns of schedule CPU time fo dead threads in the
188          * group, not including a zombie group leader, (This only differs
189          * from jiffies_to_ns(utime + stime) if sched_clock uses something
190          * other than jiffies.)
191          */
192         unsigned long long sum_sched_runtime;
193 
194         /*
195          * We don't bother to synchronize most readers of this at all,
196          * because there is no reader checking a limit that actually needs
197          * to get both rlim_cur and rlim_max atomically, and either one
198          * alone is a single word that can safely be read normally.
199          * getrlimit/setrlimit use task_lock(current->group_leader) to
200          * protect this instead of the siglock, because they really
201          * have no need to disable irqs.
202          */
203         struct rlimit rlim[RLIM_NLIMITS];
204 
205 #ifdef CONFIG_BSD_PROCESS_ACCT
206         struct pacct_struct pacct;      /* per-process accounting information */
207 #endif
208 #ifdef CONFIG_TASKSTATS
209         struct taskstats *stats;
210 #endif
211 #ifdef CONFIG_AUDIT
212         unsigned audit_tty;
213         struct tty_audit_buf *tty_audit_buf;
214 #endif
215 
216         /*
217          * Thread is the potential origin of an oom condition; kill first on
218          * oom
219          */
220         bool oom_flag_origin;
221         short oom_score_adj;            /* OOM kill score adjustment */
222         short oom_score_adj_min;        /* OOM kill score adjustment min value.
223                                          * Only settable by CAP_SYS_RESOURCE. */
224         struct mm_struct *oom_mm;       /* recorded mm when the thread group got
225                                          * killed by the oom killer */
226 
227         struct mutex cred_guard_mutex;  /* guard against foreign influences on
228                                          * credential calculations
229                                          * (notably. ptrace)
230                                          * Deprecated do not use in new code.
231                                          * Use exec_update_mutex instead.
232                                          */
233         struct mutex exec_update_mutex; /* Held while task_struct is being
234                                          * updated during exec, and may have
235                                          * inconsistent permissions.
236                                          */
237 } __randomize_layout;
238 
239 /*
240  * Bits in flags field of signal_struct.
241  */
242 #define SIGNAL_STOP_STOPPED     0x00000001 /* job control stop in effect */
243 #define SIGNAL_STOP_CONTINUED   0x00000002 /* SIGCONT since WCONTINUED reap */
244 #define SIGNAL_GROUP_EXIT       0x00000004 /* group exit in progress */
245 #define SIGNAL_GROUP_COREDUMP   0x00000008 /* coredump in progress */
246 /*
247  * Pending notifications to parent.
248  */
249 #define SIGNAL_CLD_STOPPED      0x00000010
250 #define SIGNAL_CLD_CONTINUED    0x00000020
251 #define SIGNAL_CLD_MASK         (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
252 
253 #define SIGNAL_UNKILLABLE       0x00000040 /* for init: ignore fatal signals */
254 
255 #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
256                           SIGNAL_STOP_CONTINUED)
257 
258 static inline void signal_set_stop_flags(struct signal_struct *sig,
259                                          unsigned int flags)
260 {
261         WARN_ON(sig->flags & (SIGNAL_GROUP_EXIT|SIGNAL_GROUP_COREDUMP));
262         sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
263 }
264 
265 /* If true, all threads except ->group_exit_task have pending SIGKILL */
266 static inline int signal_group_exit(const struct signal_struct *sig)
267 {
268         return  (sig->flags & SIGNAL_GROUP_EXIT) ||
269                 (sig->group_exit_task != NULL);
270 }
271 
272 extern void flush_signals(struct task_struct *);
273 extern void ignore_signals(struct task_struct *);
274 extern void flush_signal_handlers(struct task_struct *, int force_default);
275 extern int dequeue_signal(struct task_struct *task,
276                           sigset_t *mask, kernel_siginfo_t *info);
277 
278 static inline int kernel_dequeue_signal(void)
279 {
280         struct task_struct *task = current;
281         kernel_siginfo_t __info;
282         int ret;
283 
284         spin_lock_irq(&task->sighand->siglock);
285         ret = dequeue_signal(task, &task->blocked, &__info);
286         spin_unlock_irq(&task->sighand->siglock);
287 
288         return ret;
289 }
290 
291 static inline void kernel_signal_stop(void)
292 {
293         spin_lock_irq(&current->sighand->siglock);
294         if (current->jobctl & JOBCTL_STOP_DEQUEUED)
295                 set_special_state(TASK_STOPPED);
296         spin_unlock_irq(&current->sighand->siglock);
297 
298         schedule();
299 }
300 #ifdef __ARCH_SI_TRAPNO
301 # define ___ARCH_SI_TRAPNO(_a1) , _a1
302 #else
303 # define ___ARCH_SI_TRAPNO(_a1)
304 #endif
305 #ifdef __ia64__
306 # define ___ARCH_SI_IA64(_a1, _a2, _a3) , _a1, _a2, _a3
307 #else
308 # define ___ARCH_SI_IA64(_a1, _a2, _a3)
309 #endif
310 
311 int force_sig_fault_to_task(int sig, int code, void __user *addr
312         ___ARCH_SI_TRAPNO(int trapno)
313         ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
314         , struct task_struct *t);
315 int force_sig_fault(int sig, int code, void __user *addr
316         ___ARCH_SI_TRAPNO(int trapno)
317         ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr));
318 int send_sig_fault(int sig, int code, void __user *addr
319         ___ARCH_SI_TRAPNO(int trapno)
320         ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
321         , struct task_struct *t);
322 
323 int force_sig_mceerr(int code, void __user *, short);
324 int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
325 
326 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
327 int force_sig_pkuerr(void __user *addr, u32 pkey);
328 
329 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
330 
331 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
332 extern void force_sigsegv(int sig);
333 extern int force_sig_info(struct kernel_siginfo *);
334 extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
335 extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
336 extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
337                                 const struct cred *);
338 extern int kill_pgrp(struct pid *pid, int sig, int priv);
339 extern int kill_pid(struct pid *pid, int sig, int priv);
340 extern __must_check bool do_notify_parent(struct task_struct *, int);
341 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
342 extern void force_sig(int);
343 extern int send_sig(int, struct task_struct *, int);
344 extern int zap_other_threads(struct task_struct *p);
345 extern struct sigqueue *sigqueue_alloc(void);
346 extern void sigqueue_free(struct sigqueue *);
347 extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
348 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
349 
350 static inline int restart_syscall(void)
351 {
352         set_tsk_thread_flag(current, TIF_SIGPENDING);
353         return -ERESTARTNOINTR;
354 }
355 
356 static inline int signal_pending(struct task_struct *p)
357 {
358         return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
359 }
360 
361 static inline int __fatal_signal_pending(struct task_struct *p)
362 {
363         return unlikely(sigismember(&p->pending.signal, SIGKILL));
364 }
365 
366 static inline int fatal_signal_pending(struct task_struct *p)
367 {
368         return signal_pending(p) && __fatal_signal_pending(p);
369 }
370 
371 static inline int signal_pending_state(long state, struct task_struct *p)
372 {
373         if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
374                 return 0;
375         if (!signal_pending(p))
376                 return 0;
377 
378         return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
379 }
380 
381 /*
382  * This should only be used in fault handlers to decide whether we
383  * should stop the current fault routine to handle the signals
384  * instead, especially with the case where we've got interrupted with
385  * a VM_FAULT_RETRY.
386  */
387 static inline bool fault_signal_pending(vm_fault_t fault_flags,
388                                         struct pt_regs *regs)
389 {
390         return unlikely((fault_flags & VM_FAULT_RETRY) &&
391                         (fatal_signal_pending(current) ||
392                          (user_mode(regs) && signal_pending(current))));
393 }
394 
395 /*
396  * Reevaluate whether the task has signals pending delivery.
397  * Wake the task if so.
398  * This is required every time the blocked sigset_t changes.
399  * callers must hold sighand->siglock.
400  */
401 extern void recalc_sigpending_and_wake(struct task_struct *t);
402 extern void recalc_sigpending(void);
403 extern void calculate_sigpending(void);
404 
405 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
406 
407 static inline void signal_wake_up(struct task_struct *t, bool resume)
408 {
409         signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
410 }
411 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
412 {
413         signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
414 }
415 
416 void task_join_group_stop(struct task_struct *task);
417 
418 #ifdef TIF_RESTORE_SIGMASK
419 /*
420  * Legacy restore_sigmask accessors.  These are inefficient on
421  * SMP architectures because they require atomic operations.
422  */
423 
424 /**
425  * set_restore_sigmask() - make sure saved_sigmask processing gets done
426  *
427  * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
428  * will run before returning to user mode, to process the flag.  For
429  * all callers, TIF_SIGPENDING is already set or it's no harm to set
430  * it.  TIF_RESTORE_SIGMASK need not be in the set of bits that the
431  * arch code will notice on return to user mode, in case those bits
432  * are scarce.  We set TIF_SIGPENDING here to ensure that the arch
433  * signal code always gets run when TIF_RESTORE_SIGMASK is set.
434  */
435 static inline void set_restore_sigmask(void)
436 {
437         set_thread_flag(TIF_RESTORE_SIGMASK);
438 }
439 
440 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
441 {
442         clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
443 }
444 
445 static inline void clear_restore_sigmask(void)
446 {
447         clear_thread_flag(TIF_RESTORE_SIGMASK);
448 }
449 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
450 {
451         return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
452 }
453 static inline bool test_restore_sigmask(void)
454 {
455         return test_thread_flag(TIF_RESTORE_SIGMASK);
456 }
457 static inline bool test_and_clear_restore_sigmask(void)
458 {
459         return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
460 }
461 
462 #else   /* TIF_RESTORE_SIGMASK */
463 
464 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
465 static inline void set_restore_sigmask(void)
466 {
467         current->restore_sigmask = true;
468 }
469 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
470 {
471         task->restore_sigmask = false;
472 }
473 static inline void clear_restore_sigmask(void)
474 {
475         current->restore_sigmask = false;
476 }
477 static inline bool test_restore_sigmask(void)
478 {
479         return current->restore_sigmask;
480 }
481 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
482 {
483         return task->restore_sigmask;
484 }
485 static inline bool test_and_clear_restore_sigmask(void)
486 {
487         if (!current->restore_sigmask)
488                 return false;
489         current->restore_sigmask = false;
490         return true;
491 }
492 #endif
493 
494 static inline void restore_saved_sigmask(void)
495 {
496         if (test_and_clear_restore_sigmask())
497                 __set_current_blocked(&current->saved_sigmask);
498 }
499 
500 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
501 
502 static inline void restore_saved_sigmask_unless(bool interrupted)
503 {
504         if (interrupted)
505                 WARN_ON(!test_thread_flag(TIF_SIGPENDING));
506         else
507                 restore_saved_sigmask();
508 }
509 
510 static inline sigset_t *sigmask_to_save(void)
511 {
512         sigset_t *res = &current->blocked;
513         if (unlikely(test_restore_sigmask()))
514                 res = &current->saved_sigmask;
515         return res;
516 }
517 
518 static inline int kill_cad_pid(int sig, int priv)
519 {
520         return kill_pid(cad_pid, sig, priv);
521 }
522 
523 /* These can be the second arg to send_sig_info/send_group_sig_info.  */
524 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
525 #define SEND_SIG_PRIV   ((struct kernel_siginfo *) 1)
526 
527 /*
528  * True if we are on the alternate signal stack.
529  */
530 static inline int on_sig_stack(unsigned long sp)
531 {
532         /*
533          * If the signal stack is SS_AUTODISARM then, by construction, we
534          * can't be on the signal stack unless user code deliberately set
535          * SS_AUTODISARM when we were already on it.
536          *
537          * This improves reliability: if user state gets corrupted such that
538          * the stack pointer points very close to the end of the signal stack,
539          * then this check will enable the signal to be handled anyway.
540          */
541         if (current->sas_ss_flags & SS_AUTODISARM)
542                 return 0;
543 
544 #ifdef CONFIG_STACK_GROWSUP
545         return sp >= current->sas_ss_sp &&
546                 sp - current->sas_ss_sp < current->sas_ss_size;
547 #else
548         return sp > current->sas_ss_sp &&
549                 sp - current->sas_ss_sp <= current->sas_ss_size;
550 #endif
551 }
552 
553 static inline int sas_ss_flags(unsigned long sp)
554 {
555         if (!current->sas_ss_size)
556                 return SS_DISABLE;
557 
558         return on_sig_stack(sp) ? SS_ONSTACK : 0;
559 }
560 
561 static inline void sas_ss_reset(struct task_struct *p)
562 {
563         p->sas_ss_sp = 0;
564         p->sas_ss_size = 0;
565         p->sas_ss_flags = SS_DISABLE;
566 }
567 
568 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
569 {
570         if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
571 #ifdef CONFIG_STACK_GROWSUP
572                 return current->sas_ss_sp;
573 #else
574                 return current->sas_ss_sp + current->sas_ss_size;
575 #endif
576         return sp;
577 }
578 
579 extern void __cleanup_sighand(struct sighand_struct *);
580 extern void flush_itimer_signals(void);
581 
582 #define tasklist_empty() \
583         list_empty(&init_task.tasks)
584 
585 #define next_task(p) \
586         list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
587 
588 #define for_each_process(p) \
589         for (p = &init_task ; (p = next_task(p)) != &init_task ; )
590 
591 extern bool current_is_single_threaded(void);
592 
593 /*
594  * Careful: do_each_thread/while_each_thread is a double loop so
595  *          'break' will not work as expected - use goto instead.
596  */
597 #define do_each_thread(g, t) \
598         for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
599 
600 #define while_each_thread(g, t) \
601         while ((t = next_thread(t)) != g)
602 
603 #define __for_each_thread(signal, t)    \
604         list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)
605 
606 #define for_each_thread(p, t)           \
607         __for_each_thread((p)->signal, t)
608 
609 /* Careful: this is a double loop, 'break' won't work as expected. */
610 #define for_each_process_thread(p, t)   \
611         for_each_process(p) for_each_thread(p, t)
612 
613 typedef int (*proc_visitor)(struct task_struct *p, void *data);
614 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
615 
616 static inline
617 struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
618 {
619         struct pid *pid;
620         if (type == PIDTYPE_PID)
621                 pid = task_pid(task);
622         else
623                 pid = task->signal->pids[type];
624         return pid;
625 }
626 
627 static inline struct pid *task_tgid(struct task_struct *task)
628 {
629         return task->signal->pids[PIDTYPE_TGID];
630 }
631 
632 /*
633  * Without tasklist or RCU lock it is not safe to dereference
634  * the result of task_pgrp/task_session even if task == current,
635  * we can race with another thread doing sys_setsid/sys_setpgid.
636  */
637 static inline struct pid *task_pgrp(struct task_struct *task)
638 {
639         return task->signal->pids[PIDTYPE_PGID];
640 }
641 
642 static inline struct pid *task_session(struct task_struct *task)
643 {
644         return task->signal->pids[PIDTYPE_SID];
645 }
646 
647 static inline int get_nr_threads(struct task_struct *task)
648 {
649         return task->signal->nr_threads;
650 }
651 
652 static inline bool thread_group_leader(struct task_struct *p)
653 {
654         return p->exit_signal >= 0;
655 }
656 
657 static inline
658 bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
659 {
660         return p1->signal == p2->signal;
661 }
662 
663 static inline struct task_struct *next_thread(const struct task_struct *p)
664 {
665         return list_entry_rcu(p->thread_group.next,
666                               struct task_struct, thread_group);
667 }
668 
669 static inline int thread_group_empty(struct task_struct *p)
670 {
671         return list_empty(&p->thread_group);
672 }
673 
674 #define delay_group_leader(p) \
675                 (thread_group_leader(p) && !thread_group_empty(p))
676 
677 extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
678                                                         unsigned long *flags);
679 
680 static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
681                                                        unsigned long *flags)
682 {
683         struct sighand_struct *ret;
684 
685         ret = __lock_task_sighand(task, flags);
686         (void)__cond_lock(&task->sighand->siglock, ret);
687         return ret;
688 }
689 
690 static inline void unlock_task_sighand(struct task_struct *task,
691                                                 unsigned long *flags)
692 {
693         spin_unlock_irqrestore(&task->sighand->siglock, *flags);
694 }
695 
696 static inline unsigned long task_rlimit(const struct task_struct *task,
697                 unsigned int limit)
698 {
699         return READ_ONCE(task->signal->rlim[limit].rlim_cur);
700 }
701 
702 static inline unsigned long task_rlimit_max(const struct task_struct *task,
703                 unsigned int limit)
704 {
705         return READ_ONCE(task->signal->rlim[limit].rlim_max);
706 }
707 
708 static inline unsigned long rlimit(unsigned int limit)
709 {
710         return task_rlimit(current, limit);
711 }
712 
713 static inline unsigned long rlimit_max(unsigned int limit)
714 {
715         return task_rlimit_max(current, limit);
716 }
717 
718 #endif /* _LINUX_SCHED_SIGNAL_H */
719 

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