signal.h

  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/pid.h>
 13#include <linux/posix-timers.h>
 14#include <linux/mm_types.h>
 15#include <asm/ptrace.h>
 16
 17/*
 18 * Types defining task->signal and task->sighand and APIs using them:
 19 */
 20
 21struct sighand_struct {
 22	spinlock_t		siglock;
 23	refcount_t		count;
 24	wait_queue_head_t	signalfd_wqh;
 25	struct k_sigaction	action[_NSIG];
 26};
 27
 28/*
 29 * Per-process accounting stats:
 30 */
 31struct pacct_struct {
 32	int			ac_flag;
 33	long			ac_exitcode;
 34	unsigned long		ac_mem;
 35	u64			ac_utime, ac_stime;
 36	unsigned long		ac_minflt, ac_majflt;
 37};
 38
 39struct cpu_itimer {
 40	u64 expires;
 41	u64 incr;
 42};
 43
 44/*
 45 * This is the atomic variant of task_cputime, which can be used for
 46 * storing and updating task_cputime statistics without locking.
 47 */
 48struct task_cputime_atomic {
 49	atomic64_t utime;
 50	atomic64_t stime;
 51	atomic64_t sum_exec_runtime;
 52};
 53
 54#define INIT_CPUTIME_ATOMIC \
 55	(struct task_cputime_atomic) {				\
 56		.utime = ATOMIC64_INIT(0),			\
 57		.stime = ATOMIC64_INIT(0),			\
 58		.sum_exec_runtime = ATOMIC64_INIT(0),		\
 59	}
 60/**
 61 * struct thread_group_cputimer - thread group interval timer counts
 62 * @cputime_atomic:	atomic thread group interval timers.
 63 *
 64 * This structure contains the version of task_cputime, above, that is
 65 * used for thread group CPU timer calculations.
 66 */
 67struct thread_group_cputimer {
 68	struct task_cputime_atomic cputime_atomic;
 69};
 70
 71struct multiprocess_signals {
 72	sigset_t signal;
 73	struct hlist_node node;
 74};
 75
 76struct core_thread {
 77	struct task_struct *task;
 78	struct core_thread *next;
 79};
 80
 81struct core_state {
 82	atomic_t nr_threads;
 83	struct core_thread dumper;
 84	struct completion startup;
 85};
 86
 87/*
 88 * NOTE! "signal_struct" does not have its own
 89 * locking, because a shared signal_struct always
 90 * implies a shared sighand_struct, so locking
 91 * sighand_struct is always a proper superset of
 92 * the locking of signal_struct.
 93 */
 94struct signal_struct {
 95	refcount_t		sigcnt;
 96	atomic_t		live;
 97	int			nr_threads;
 98	int			quick_threads;
 99	struct list_head	thread_head;
100
101	wait_queue_head_t	wait_chldexit;	/* for wait4() */
102
103	/* current thread group signal load-balancing target: */
104	struct task_struct	*curr_target;
105
106	/* shared signal handling: */
107	struct sigpending	shared_pending;
108
109	/* For collecting multiprocess signals during fork */
110	struct hlist_head	multiprocess;
111
112	/* thread group exit support */
113	int			group_exit_code;
114	/* notify group_exec_task when notify_count is less or equal to 0 */
115	int			notify_count;
116	struct task_struct	*group_exec_task;
117
118	/* thread group stop support, overloads group_exit_code too */
119	int			group_stop_count;
120	unsigned int		flags; /* see SIGNAL_* flags below */
121
122	struct core_state *core_state; /* coredumping support */
123
124	/*
125	 * PR_SET_CHILD_SUBREAPER marks a process, like a service
126	 * manager, to re-parent orphan (double-forking) child processes
127	 * to this process instead of 'init'. The service manager is
128	 * able to receive SIGCHLD signals and is able to investigate
129	 * the process until it calls wait(). All children of this
130	 * process will inherit a flag if they should look for a
131	 * child_subreaper process at exit.
132	 */
133	unsigned int		is_child_subreaper:1;
134	unsigned int		has_child_subreaper:1;
135
136#ifdef CONFIG_POSIX_TIMERS
137
138	/* POSIX.1b Interval Timers */
139	unsigned int		timer_create_restore_ids:1;
140	atomic_t		next_posix_timer_id;
141	struct hlist_head	posix_timers;
142	struct hlist_head	ignored_posix_timers;
143
144	/* ITIMER_REAL timer for the process */
145	struct hrtimer real_timer;
146	ktime_t it_real_incr;
147
148	/*
149	 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
150	 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
151	 * values are defined to 0 and 1 respectively
152	 */
153	struct cpu_itimer it[2];
154
155	/*
156	 * Thread group totals for process CPU timers.
157	 * See thread_group_cputimer(), et al, for details.
158	 */
159	struct thread_group_cputimer cputimer;
160
161#endif
162	/* Empty if CONFIG_POSIX_TIMERS=n */
163	struct posix_cputimers posix_cputimers;
164
165	/* PID/PID hash table linkage. */
166	struct pid *pids[PIDTYPE_MAX];
167
168#ifdef CONFIG_NO_HZ_FULL
169	atomic_t tick_dep_mask;
170#endif
171
172	struct pid *tty_old_pgrp;
173
174	/* boolean value for session group leader */
175	int leader;
176
177	struct tty_struct *tty; /* NULL if no tty */
178
179#ifdef CONFIG_SCHED_AUTOGROUP
180	struct autogroup *autogroup;
181#endif
182	/*
183	 * Cumulative resource counters for dead threads in the group,
184	 * and for reaped dead child processes forked by this group.
185	 * Live threads maintain their own counters and add to these
186	 * in __exit_signal, except for the group leader.
187	 */
188	seqlock_t stats_lock;
189	u64 utime, stime, cutime, cstime;
190	u64 gtime;
191	u64 cgtime;
192	struct prev_cputime prev_cputime;
193	unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
194	unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
195	unsigned long inblock, oublock, cinblock, coublock;
196	unsigned long maxrss, cmaxrss;
197	struct task_io_accounting ioac;
198
199	/*
200	 * Cumulative ns of schedule CPU time fo dead threads in the
201	 * group, not including a zombie group leader, (This only differs
202	 * from jiffies_to_ns(utime + stime) if sched_clock uses something
203	 * other than jiffies.)
204	 */
205	unsigned long long sum_sched_runtime;
206
207	/*
208	 * We don't bother to synchronize most readers of this at all,
209	 * because there is no reader checking a limit that actually needs
210	 * to get both rlim_cur and rlim_max atomically, and either one
211	 * alone is a single word that can safely be read normally.
212	 * getrlimit/setrlimit use task_lock(current->group_leader) to
213	 * protect this instead of the siglock, because they really
214	 * have no need to disable irqs.
215	 */
216	struct rlimit rlim[RLIM_NLIMITS];
217
218#ifdef CONFIG_BSD_PROCESS_ACCT
219	struct pacct_struct pacct;	/* per-process accounting information */
220#endif
221#ifdef CONFIG_TASKSTATS
222	struct taskstats *stats;
223#endif
224#ifdef CONFIG_AUDIT
225	unsigned audit_tty;
226	struct tty_audit_buf *tty_audit_buf;
227#endif
228
229#ifdef CONFIG_CGROUPS
230	struct rw_semaphore cgroup_threadgroup_rwsem;
231#endif
232
233	/*
234	 * Thread is the potential origin of an oom condition; kill first on
235	 * oom
236	 */
237	bool oom_flag_origin;
238	short oom_score_adj;		/* OOM kill score adjustment */
239	short oom_score_adj_min;	/* OOM kill score adjustment min value.
240					 * Only settable by CAP_SYS_RESOURCE. */
241	struct mm_struct *oom_mm;	/* recorded mm when the thread group got
242					 * killed by the oom killer */
243
244	struct mutex cred_guard_mutex;	/* guard against foreign influences on
245					 * credential calculations
246					 * (notably. ptrace)
247					 * Deprecated do not use in new code.
248					 * Use exec_update_lock instead.
249					 */
250	struct rw_semaphore exec_update_lock;	/* Held while task_struct is
251						 * being updated during exec,
252						 * and may have inconsistent
253						 * permissions.
254						 */
255} __randomize_layout;
256
257/*
258 * Bits in flags field of signal_struct.
259 */
260#define SIGNAL_STOP_STOPPED	0x00000001 /* job control stop in effect */
261#define SIGNAL_STOP_CONTINUED	0x00000002 /* SIGCONT since WCONTINUED reap */
262#define SIGNAL_GROUP_EXIT	0x00000004 /* group exit in progress */
263/*
264 * Pending notifications to parent.
265 */
266#define SIGNAL_CLD_STOPPED	0x00000010
267#define SIGNAL_CLD_CONTINUED	0x00000020
268#define SIGNAL_CLD_MASK		(SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
269
270#define SIGNAL_UNKILLABLE	0x00000040 /* for init: ignore fatal signals */
271
272#define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
273			  SIGNAL_STOP_CONTINUED)
274
275static inline void signal_set_stop_flags(struct signal_struct *sig,
276					 unsigned int flags)
277{
278	WARN_ON(sig->flags & SIGNAL_GROUP_EXIT);
279	sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
280}
281
282extern void flush_signals(struct task_struct *);
283extern void ignore_signals(struct task_struct *);
284extern void flush_signal_handlers(struct task_struct *, int force_default);
285extern int dequeue_signal(sigset_t *mask, kernel_siginfo_t *info, enum pid_type *type);
286
287static inline int kernel_dequeue_signal(void)
288{
289	struct task_struct *task = current;
290	kernel_siginfo_t __info;
291	enum pid_type __type;
292	int ret;
293
294	spin_lock_irq(&task->sighand->siglock);
295	ret = dequeue_signal(&task->blocked, &__info, &__type);
296	spin_unlock_irq(&task->sighand->siglock);
297
298	return ret;
299}
300
301static inline void kernel_signal_stop(void)
302{
303	spin_lock_irq(&current->sighand->siglock);
304	if (current->jobctl & JOBCTL_STOP_DEQUEUED) {
305		current->jobctl |= JOBCTL_STOPPED;
306		set_special_state(TASK_STOPPED);
307	}
308	spin_unlock_irq(&current->sighand->siglock);
309
310	schedule();
311}
312
313int force_sig_fault_to_task(int sig, int code, void __user *addr,
314			    struct task_struct *t);
315int force_sig_fault(int sig, int code, void __user *addr);
316int send_sig_fault(int sig, int code, void __user *addr, struct task_struct *t);
317
318int force_sig_mceerr(int code, void __user *, short);
319int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
320
321int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
322int force_sig_pkuerr(void __user *addr, u32 pkey);
323int send_sig_perf(void __user *addr, u32 type, u64 sig_data);
324
325int force_sig_ptrace_errno_trap(int errno, void __user *addr);
326int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
327int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
328			struct task_struct *t);
329int force_sig_seccomp(int syscall, int reason, bool force_coredump);
330
331extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
332extern void force_sigsegv(int sig);
333extern int force_sig_info(struct kernel_siginfo *);
334extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
335extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
336extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
337				const struct cred *);
338extern int kill_pgrp(struct pid *pid, int sig, int priv);
339extern int kill_pid(struct pid *pid, int sig, int priv);
340extern __must_check bool do_notify_parent(struct task_struct *, int);
341extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
342extern void force_sig(int);
343extern void force_fatal_sig(int);
344extern void force_exit_sig(int);
345extern int send_sig(int, struct task_struct *, int);
346extern int zap_other_threads(struct task_struct *p);
347extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
348
349static inline void clear_notify_signal(void)
350{
351	clear_thread_flag(TIF_NOTIFY_SIGNAL);
352	smp_mb__after_atomic();
353}
354
355/*
356 * Returns 'true' if kick_process() is needed to force a transition from
357 * user -> kernel to guarantee expedient run of TWA_SIGNAL based task_work.
358 */
359static inline bool __set_notify_signal(struct task_struct *task)
360{
361	return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) &&
362	       !wake_up_state(task, TASK_INTERRUPTIBLE);
363}
364
365/*
366 * Called to break out of interruptible wait loops, and enter the
367 * exit_to_user_mode_loop().
368 */
369static inline void set_notify_signal(struct task_struct *task)
370{
371	if (__set_notify_signal(task))
372		kick_process(task);
373}
374
375static inline int restart_syscall(void)
376{
377	set_tsk_thread_flag(current, TIF_SIGPENDING);
378	return -ERESTARTNOINTR;
379}
380
381static inline int task_sigpending(struct task_struct *p)
382{
383	return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
384}
385
386static inline int signal_pending(struct task_struct *p)
387{
388	/*
389	 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
390	 * behavior in terms of ensuring that we break out of wait loops
391	 * so that notify signal callbacks can be processed.
392	 */
393	if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
394		return 1;
395	return task_sigpending(p);
396}
397
398static inline int __fatal_signal_pending(struct task_struct *p)
399{
400	return unlikely(sigismember(&p->pending.signal, SIGKILL));
401}
402
403static inline int fatal_signal_pending(struct task_struct *p)
404{
405	return task_sigpending(p) && __fatal_signal_pending(p);
406}
407
408static inline int signal_pending_state(unsigned int state, struct task_struct *p)
409{
410	if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
411		return 0;
412	if (!signal_pending(p))
413		return 0;
414
415	return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
416}
417
418/*
419 * This should only be used in fault handlers to decide whether we
420 * should stop the current fault routine to handle the signals
421 * instead, especially with the case where we've got interrupted with
422 * a VM_FAULT_RETRY.
423 */
424static inline bool fault_signal_pending(vm_fault_t fault_flags,
425					struct pt_regs *regs)
426{
427	return unlikely((fault_flags & VM_FAULT_RETRY) &&
428			(fatal_signal_pending(current) ||
429			 (user_mode(regs) && signal_pending(current))));
430}
431
432/*
433 * Reevaluate whether the task has signals pending delivery.
434 * Wake the task if so.
435 * This is required every time the blocked sigset_t changes.
436 * callers must hold sighand->siglock.
437 */
438extern void recalc_sigpending(void);
439extern void calculate_sigpending(void);
440
441extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
442
443static inline void signal_wake_up(struct task_struct *t, bool fatal)
444{
445	unsigned int state = 0;
446	if (fatal && !(t->jobctl & JOBCTL_PTRACE_FROZEN)) {
447		t->jobctl &= ~(JOBCTL_STOPPED | JOBCTL_TRACED);
448		state = TASK_WAKEKILL | __TASK_TRACED;
449	}
450	signal_wake_up_state(t, state);
451}
452static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
453{
454	unsigned int state = 0;
455	if (resume) {
456		t->jobctl &= ~JOBCTL_TRACED;
457		state = __TASK_TRACED;
458	}
459	signal_wake_up_state(t, state);
460}
461
462void task_join_group_stop(struct task_struct *task);
463
464#ifdef TIF_RESTORE_SIGMASK
465/*
466 * Legacy restore_sigmask accessors.  These are inefficient on
467 * SMP architectures because they require atomic operations.
468 */
469
470/**
471 * set_restore_sigmask() - make sure saved_sigmask processing gets done
472 *
473 * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
474 * will run before returning to user mode, to process the flag.  For
475 * all callers, TIF_SIGPENDING is already set or it's no harm to set
476 * it.  TIF_RESTORE_SIGMASK need not be in the set of bits that the
477 * arch code will notice on return to user mode, in case those bits
478 * are scarce.  We set TIF_SIGPENDING here to ensure that the arch
479 * signal code always gets run when TIF_RESTORE_SIGMASK is set.
480 */
481static inline void set_restore_sigmask(void)
482{
483	set_thread_flag(TIF_RESTORE_SIGMASK);
484}
485
486static inline void clear_tsk_restore_sigmask(struct task_struct *task)
487{
488	clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
489}
490
491static inline void clear_restore_sigmask(void)
492{
493	clear_thread_flag(TIF_RESTORE_SIGMASK);
494}
495static inline bool test_tsk_restore_sigmask(struct task_struct *task)
496{
497	return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
498}
499static inline bool test_restore_sigmask(void)
500{
501	return test_thread_flag(TIF_RESTORE_SIGMASK);
502}
503static inline bool test_and_clear_restore_sigmask(void)
504{
505	return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
506}
507
508#else	/* TIF_RESTORE_SIGMASK */
509
510/* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
511static inline void set_restore_sigmask(void)
512{
513	current->restore_sigmask = true;
514}
515static inline void clear_tsk_restore_sigmask(struct task_struct *task)
516{
517	task->restore_sigmask = false;
518}
519static inline void clear_restore_sigmask(void)
520{
521	current->restore_sigmask = false;
522}
523static inline bool test_restore_sigmask(void)
524{
525	return current->restore_sigmask;
526}
527static inline bool test_tsk_restore_sigmask(struct task_struct *task)
528{
529	return task->restore_sigmask;
530}
531static inline bool test_and_clear_restore_sigmask(void)
532{
533	if (!current->restore_sigmask)
534		return false;
535	current->restore_sigmask = false;
536	return true;
537}
538#endif
539
540static inline void restore_saved_sigmask(void)
541{
542	if (test_and_clear_restore_sigmask())
543		__set_current_blocked(&current->saved_sigmask);
544}
545
546extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
547
548static inline void restore_saved_sigmask_unless(bool interrupted)
549{
550	if (interrupted)
551		WARN_ON(!signal_pending(current));
552	else
553		restore_saved_sigmask();
554}
555
556static inline sigset_t *sigmask_to_save(void)
557{
558	sigset_t *res = &current->blocked;
559	if (unlikely(test_restore_sigmask()))
560		res = &current->saved_sigmask;
561	return res;
562}
563
564static inline int kill_cad_pid(int sig, int priv)
565{
566	return kill_pid(cad_pid, sig, priv);
567}
568
569/* These can be the second arg to send_sig_info/send_group_sig_info.  */
570#define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
571#define SEND_SIG_PRIV	((struct kernel_siginfo *) 1)
572
573static inline int __on_sig_stack(unsigned long sp)
574{
575#ifdef CONFIG_STACK_GROWSUP
576	return sp >= current->sas_ss_sp &&
577		sp - current->sas_ss_sp < current->sas_ss_size;
578#else
579	return sp > current->sas_ss_sp &&
580		sp - current->sas_ss_sp <= current->sas_ss_size;
581#endif
582}
583
584/*
585 * True if we are on the alternate signal stack.
586 */
587static inline int on_sig_stack(unsigned long sp)
588{
589	/*
590	 * If the signal stack is SS_AUTODISARM then, by construction, we
591	 * can't be on the signal stack unless user code deliberately set
592	 * SS_AUTODISARM when we were already on it.
593	 *
594	 * This improves reliability: if user state gets corrupted such that
595	 * the stack pointer points very close to the end of the signal stack,
596	 * then this check will enable the signal to be handled anyway.
597	 */
598	if (current->sas_ss_flags & SS_AUTODISARM)
599		return 0;
600
601	return __on_sig_stack(sp);
602}
603
604static inline int sas_ss_flags(unsigned long sp)
605{
606	if (!current->sas_ss_size)
607		return SS_DISABLE;
608
609	return on_sig_stack(sp) ? SS_ONSTACK : 0;
610}
611
612static inline void sas_ss_reset(struct task_struct *p)
613{
614	p->sas_ss_sp = 0;
615	p->sas_ss_size = 0;
616	p->sas_ss_flags = SS_DISABLE;
617}
618
619static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
620{
621	if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
622#ifdef CONFIG_STACK_GROWSUP
623		return current->sas_ss_sp;
624#else
625		return current->sas_ss_sp + current->sas_ss_size;
626#endif
627	return sp;
628}
629
630extern void __cleanup_sighand(struct sighand_struct *);
631extern void flush_itimer_signals(void);
632
633#define tasklist_empty() \
634	list_empty(&init_task.tasks)
635
636#define next_task(p) \
637	list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
638
639#define for_each_process(p) \
640	for (p = &init_task ; (p = next_task(p)) != &init_task ; )
641
642extern bool current_is_single_threaded(void);
643
644/*
645 * Without tasklist/siglock it is only rcu-safe if g can't exit/exec,
646 * otherwise next_thread(t) will never reach g after list_del_rcu(g).
647 */
648#define while_each_thread(g, t) \
649	while ((t = next_thread(t)) != g)
650
651#define for_other_threads(p, t)	\
652	for (t = p; (t = next_thread(t)) != p; )
653
654#define __for_each_thread(signal, t)	\
655	list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node, \
656		lockdep_is_held(&tasklist_lock))
657
658#define for_each_thread(p, t)		\
659	__for_each_thread((p)->signal, t)
660
661/* Careful: this is a double loop, 'break' won't work as expected. */
662#define for_each_process_thread(p, t)	\
663	for_each_process(p) for_each_thread(p, t)
664
665typedef int (*proc_visitor)(struct task_struct *p, void *data);
666void walk_process_tree(struct task_struct *top, proc_visitor, void *);
667
668static inline
669struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
670{
671	struct pid *pid;
672	if (type == PIDTYPE_PID)
673		pid = task_pid(task);
674	else
675		pid = task->signal->pids[type];
676	return pid;
677}
678
679static inline struct pid *task_tgid(struct task_struct *task)
680{
681	return task->signal->pids[PIDTYPE_TGID];
682}
683
684/*
685 * Without tasklist or RCU lock it is not safe to dereference
686 * the result of task_pgrp/task_session even if task == current,
687 * we can race with another thread doing sys_setsid/sys_setpgid.
688 */
689static inline struct pid *task_pgrp(struct task_struct *task)
690{
691	return task->signal->pids[PIDTYPE_PGID];
692}
693
694static inline struct pid *task_session(struct task_struct *task)
695{
696	return task->signal->pids[PIDTYPE_SID];
697}
698
699static inline int get_nr_threads(struct task_struct *task)
700{
701	return task->signal->nr_threads;
702}
703
704static inline bool thread_group_leader(struct task_struct *p)
705{
706	return p->exit_signal >= 0;
707}
708
709static inline
710bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
711{
712	return p1->signal == p2->signal;
713}
714
715/*
716 * returns NULL if p is the last thread in the thread group
717 */
718static inline struct task_struct *__next_thread(struct task_struct *p)
719{
720	return list_next_or_null_rcu(&p->signal->thread_head,
721					&p->thread_node,
722					struct task_struct,
723					thread_node);
724}
725
726static inline struct task_struct *next_thread(struct task_struct *p)
727{
728	return __next_thread(p) ?: p->group_leader;
729}
730
731static inline int thread_group_empty(struct task_struct *p)
732{
733	return thread_group_leader(p) &&
734	       list_is_last(&p->thread_node, &p->signal->thread_head);
735}
736
737#define delay_group_leader(p) \
738		(thread_group_leader(p) && !thread_group_empty(p))
739
740extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
741							unsigned long *flags);
742
743static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
744						       unsigned long *flags)
745{
746	struct sighand_struct *ret;
747
748	ret = __lock_task_sighand(task, flags);
749	(void)__cond_lock(&task->sighand->siglock, ret);
750	return ret;
751}
752
753static inline void unlock_task_sighand(struct task_struct *task,
754						unsigned long *flags)
755{
756	spin_unlock_irqrestore(&task->sighand->siglock, *flags);
757}
758
759#ifdef CONFIG_LOCKDEP
760extern void lockdep_assert_task_sighand_held(struct task_struct *task);
761#else
762static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { }
763#endif
764
765static inline unsigned long task_rlimit(const struct task_struct *task,
766		unsigned int limit)
767{
768	return READ_ONCE(task->signal->rlim[limit].rlim_cur);
769}
770
771static inline unsigned long task_rlimit_max(const struct task_struct *task,
772		unsigned int limit)
773{
774	return READ_ONCE(task->signal->rlim[limit].rlim_max);
775}
776
777static inline unsigned long rlimit(unsigned int limit)
778{
779	return task_rlimit(current, limit);
780}
781
782static inline unsigned long rlimit_max(unsigned int limit)
783{
784	return task_rlimit_max(current, limit);
785}
786
787#endif /* _LINUX_SCHED_SIGNAL_H */