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 struct core_thread {
76 	struct task_struct *task;
77 	struct core_thread *next;
78 };
79 
80 struct core_state {
81 	atomic_t nr_threads;
82 	struct core_thread dumper;
83 	struct completion startup;
84 };
85 
86 /*
87  * NOTE! "signal_struct" does not have its own
88  * locking, because a shared signal_struct always
89  * implies a shared sighand_struct, so locking
90  * sighand_struct is always a proper superset of
91  * the locking of signal_struct.
92  */
93 struct signal_struct {
94 	refcount_t		sigcnt;
95 	atomic_t		live;
96 	int			nr_threads;
97 	struct list_head	thread_head;
98 
99 	wait_queue_head_t	wait_chldexit;	/* for wait4() */
100 
101 	/* current thread group signal load-balancing target: */
102 	struct task_struct	*curr_target;
103 
104 	/* shared signal handling: */
105 	struct sigpending	shared_pending;
106 
107 	/* For collecting multiprocess signals during fork */
108 	struct hlist_head	multiprocess;
109 
110 	/* thread group exit support */
111 	int			group_exit_code;
112 	/* notify group_exec_task when notify_count is less or equal to 0 */
113 	int			notify_count;
114 	struct task_struct	*group_exec_task;
115 
116 	/* thread group stop support, overloads group_exit_code too */
117 	int			group_stop_count;
118 	unsigned int		flags; /* see SIGNAL_* flags below */
119 
120 	struct core_state *core_state; /* coredumping support */
121 
122 	/*
123 	 * PR_SET_CHILD_SUBREAPER marks a process, like a service
124 	 * manager, to re-parent orphan (double-forking) child processes
125 	 * to this process instead of 'init'. The service manager is
126 	 * able to receive SIGCHLD signals and is able to investigate
127 	 * the process until it calls wait(). All children of this
128 	 * process will inherit a flag if they should look for a
129 	 * child_subreaper process at exit.
130 	 */
131 	unsigned int		is_child_subreaper:1;
132 	unsigned int		has_child_subreaper:1;
133 
134 #ifdef CONFIG_POSIX_TIMERS
135 
136 	/* POSIX.1b Interval Timers */
137 	int			posix_timer_id;
138 	struct list_head	posix_timers;
139 
140 	/* ITIMER_REAL timer for the process */
141 	struct hrtimer real_timer;
142 	ktime_t it_real_incr;
143 
144 	/*
145 	 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
146 	 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
147 	 * values are defined to 0 and 1 respectively
148 	 */
149 	struct cpu_itimer it[2];
150 
151 	/*
152 	 * Thread group totals for process CPU timers.
153 	 * See thread_group_cputimer(), et al, for details.
154 	 */
155 	struct thread_group_cputimer cputimer;
156 
157 #endif
158 	/* Empty if CONFIG_POSIX_TIMERS=n */
159 	struct posix_cputimers posix_cputimers;
160 
161 	/* PID/PID hash table linkage. */
162 	struct pid *pids[PIDTYPE_MAX];
163 
164 #ifdef CONFIG_NO_HZ_FULL
165 	atomic_t tick_dep_mask;
166 #endif
167 
168 	struct pid *tty_old_pgrp;
169 
170 	/* boolean value for session group leader */
171 	int leader;
172 
173 	struct tty_struct *tty; /* NULL if no tty */
174 
175 #ifdef CONFIG_SCHED_AUTOGROUP
176 	struct autogroup *autogroup;
177 #endif
178 	/*
179 	 * Cumulative resource counters for dead threads in the group,
180 	 * and for reaped dead child processes forked by this group.
181 	 * Live threads maintain their own counters and add to these
182 	 * in __exit_signal, except for the group leader.
183 	 */
184 	seqlock_t stats_lock;
185 	u64 utime, stime, cutime, cstime;
186 	u64 gtime;
187 	u64 cgtime;
188 	struct prev_cputime prev_cputime;
189 	unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
190 	unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
191 	unsigned long inblock, oublock, cinblock, coublock;
192 	unsigned long maxrss, cmaxrss;
193 	struct task_io_accounting ioac;
194 
195 	/*
196 	 * Cumulative ns of schedule CPU time fo dead threads in the
197 	 * group, not including a zombie group leader, (This only differs
198 	 * from jiffies_to_ns(utime + stime) if sched_clock uses something
199 	 * other than jiffies.)
200 	 */
201 	unsigned long long sum_sched_runtime;
202 
203 	/*
204 	 * We don't bother to synchronize most readers of this at all,
205 	 * because there is no reader checking a limit that actually needs
206 	 * to get both rlim_cur and rlim_max atomically, and either one
207 	 * alone is a single word that can safely be read normally.
208 	 * getrlimit/setrlimit use task_lock(current->group_leader) to
209 	 * protect this instead of the siglock, because they really
210 	 * have no need to disable irqs.
211 	 */
212 	struct rlimit rlim[RLIM_NLIMITS];
213 
214 #ifdef CONFIG_BSD_PROCESS_ACCT
215 	struct pacct_struct pacct;	/* per-process accounting information */
216 #endif
217 #ifdef CONFIG_TASKSTATS
218 	struct taskstats *stats;
219 #endif
220 #ifdef CONFIG_AUDIT
221 	unsigned audit_tty;
222 	struct tty_audit_buf *tty_audit_buf;
223 #endif
224 
225 	/*
226 	 * Thread is the potential origin of an oom condition; kill first on
227 	 * oom
228 	 */
229 	bool oom_flag_origin;
230 	short oom_score_adj;		/* OOM kill score adjustment */
231 	short oom_score_adj_min;	/* OOM kill score adjustment min value.
232 					 * Only settable by CAP_SYS_RESOURCE. */
233 	struct mm_struct *oom_mm;	/* recorded mm when the thread group got
234 					 * killed by the oom killer */
235 
236 	struct mutex cred_guard_mutex;	/* guard against foreign influences on
237 					 * credential calculations
238 					 * (notably. ptrace)
239 					 * Deprecated do not use in new code.
240 					 * Use exec_update_lock instead.
241 					 */
242 	struct rw_semaphore exec_update_lock;	/* Held while task_struct is
243 						 * being updated during exec,
244 						 * and may have inconsistent
245 						 * permissions.
246 						 */
247 } __randomize_layout;
248 
249 /*
250  * Bits in flags field of signal_struct.
251  */
252 #define SIGNAL_STOP_STOPPED	0x00000001 /* job control stop in effect */
253 #define SIGNAL_STOP_CONTINUED	0x00000002 /* SIGCONT since WCONTINUED reap */
254 #define SIGNAL_GROUP_EXIT	0x00000004 /* group exit in progress */
255 /*
256  * Pending notifications to parent.
257  */
258 #define SIGNAL_CLD_STOPPED	0x00000010
259 #define SIGNAL_CLD_CONTINUED	0x00000020
260 #define SIGNAL_CLD_MASK		(SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
261 
262 #define SIGNAL_UNKILLABLE	0x00000040 /* for init: ignore fatal signals */
263 
264 #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
265 			  SIGNAL_STOP_CONTINUED)
266 
signal_set_stop_flags(struct signal_struct * sig,unsigned int flags)267 static inline void signal_set_stop_flags(struct signal_struct *sig,
268 					 unsigned int flags)
269 {
270 	WARN_ON(sig->flags & SIGNAL_GROUP_EXIT);
271 	sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
272 }
273 
274 extern void flush_signals(struct task_struct *);
275 extern void ignore_signals(struct task_struct *);
276 extern void flush_signal_handlers(struct task_struct *, int force_default);
277 extern int dequeue_signal(struct task_struct *task, sigset_t *mask,
278 			  kernel_siginfo_t *info, enum pid_type *type);
279 
kernel_dequeue_signal(void)280 static inline int kernel_dequeue_signal(void)
281 {
282 	struct task_struct *task = current;
283 	kernel_siginfo_t __info;
284 	enum pid_type __type;
285 	int ret;
286 
287 	spin_lock_irq(&task->sighand->siglock);
288 	ret = dequeue_signal(task, &task->blocked, &__info, &__type);
289 	spin_unlock_irq(&task->sighand->siglock);
290 
291 	return ret;
292 }
293 
kernel_signal_stop(void)294 static inline void kernel_signal_stop(void)
295 {
296 	spin_lock_irq(&current->sighand->siglock);
297 	if (current->jobctl & JOBCTL_STOP_DEQUEUED) {
298 		current->jobctl |= JOBCTL_STOPPED;
299 		set_special_state(TASK_STOPPED);
300 	}
301 	spin_unlock_irq(&current->sighand->siglock);
302 
303 	schedule();
304 }
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_IA64(int imm, unsigned int flags, unsigned long isr)
313 	, struct task_struct *t);
314 int force_sig_fault(int sig, int code, void __user *addr
315 	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr));
316 int send_sig_fault(int sig, int code, void __user *addr
317 	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
318 	, struct task_struct *t);
319 
320 int force_sig_mceerr(int code, void __user *, short);
321 int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
322 
323 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
324 int force_sig_pkuerr(void __user *addr, u32 pkey);
325 int send_sig_perf(void __user *addr, u32 type, u64 sig_data);
326 
327 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
328 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
329 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
330 			struct task_struct *t);
331 int force_sig_seccomp(int syscall, int reason, bool force_coredump);
332 
333 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
334 extern void force_sigsegv(int sig);
335 extern int force_sig_info(struct kernel_siginfo *);
336 extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
337 extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
338 extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
339 				const struct cred *);
340 extern int kill_pgrp(struct pid *pid, int sig, int priv);
341 extern int kill_pid(struct pid *pid, int sig, int priv);
342 extern __must_check bool do_notify_parent(struct task_struct *, int);
343 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
344 extern void force_sig(int);
345 extern void force_fatal_sig(int);
346 extern void force_exit_sig(int);
347 extern int send_sig(int, struct task_struct *, int);
348 extern int zap_other_threads(struct task_struct *p);
349 extern struct sigqueue *sigqueue_alloc(void);
350 extern void sigqueue_free(struct sigqueue *);
351 extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
352 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
353 
clear_notify_signal(void)354 static inline void clear_notify_signal(void)
355 {
356 	clear_thread_flag(TIF_NOTIFY_SIGNAL);
357 	smp_mb__after_atomic();
358 }
359 
360 /*
361  * Returns 'true' if kick_process() is needed to force a transition from
362  * user -> kernel to guarantee expedient run of TWA_SIGNAL based task_work.
363  */
__set_notify_signal(struct task_struct * task)364 static inline bool __set_notify_signal(struct task_struct *task)
365 {
366 	return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) &&
367 	       !wake_up_state(task, TASK_INTERRUPTIBLE);
368 }
369 
370 /*
371  * Called to break out of interruptible wait loops, and enter the
372  * exit_to_user_mode_loop().
373  */
set_notify_signal(struct task_struct * task)374 static inline void set_notify_signal(struct task_struct *task)
375 {
376 	if (__set_notify_signal(task))
377 		kick_process(task);
378 }
379 
restart_syscall(void)380 static inline int restart_syscall(void)
381 {
382 	set_tsk_thread_flag(current, TIF_SIGPENDING);
383 	return -ERESTARTNOINTR;
384 }
385 
task_sigpending(struct task_struct * p)386 static inline int task_sigpending(struct task_struct *p)
387 {
388 	return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
389 }
390 
signal_pending(struct task_struct * p)391 static inline int signal_pending(struct task_struct *p)
392 {
393 	/*
394 	 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
395 	 * behavior in terms of ensuring that we break out of wait loops
396 	 * so that notify signal callbacks can be processed.
397 	 */
398 	if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
399 		return 1;
400 	return task_sigpending(p);
401 }
402 
__fatal_signal_pending(struct task_struct * p)403 static inline int __fatal_signal_pending(struct task_struct *p)
404 {
405 	return unlikely(sigismember(&p->pending.signal, SIGKILL));
406 }
407 
fatal_signal_pending(struct task_struct * p)408 static inline int fatal_signal_pending(struct task_struct *p)
409 {
410 	return task_sigpending(p) && __fatal_signal_pending(p);
411 }
412 
signal_pending_state(unsigned int state,struct task_struct * p)413 static inline int signal_pending_state(unsigned int state, struct task_struct *p)
414 {
415 	if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
416 		return 0;
417 	if (!signal_pending(p))
418 		return 0;
419 
420 	return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
421 }
422 
423 /*
424  * This should only be used in fault handlers to decide whether we
425  * should stop the current fault routine to handle the signals
426  * instead, especially with the case where we've got interrupted with
427  * a VM_FAULT_RETRY.
428  */
fault_signal_pending(vm_fault_t fault_flags,struct pt_regs * regs)429 static inline bool fault_signal_pending(vm_fault_t fault_flags,
430 					struct pt_regs *regs)
431 {
432 	return unlikely((fault_flags & VM_FAULT_RETRY) &&
433 			(fatal_signal_pending(current) ||
434 			 (user_mode(regs) && signal_pending(current))));
435 }
436 
437 /*
438  * Reevaluate whether the task has signals pending delivery.
439  * Wake the task if so.
440  * This is required every time the blocked sigset_t changes.
441  * callers must hold sighand->siglock.
442  */
443 extern void recalc_sigpending_and_wake(struct task_struct *t);
444 extern void recalc_sigpending(void);
445 extern void calculate_sigpending(void);
446 
447 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
448 
signal_wake_up(struct task_struct * t,bool fatal)449 static inline void signal_wake_up(struct task_struct *t, bool fatal)
450 {
451 	unsigned int state = 0;
452 	if (fatal && !(t->jobctl & JOBCTL_PTRACE_FROZEN)) {
453 		t->jobctl &= ~(JOBCTL_STOPPED | JOBCTL_TRACED);
454 		state = TASK_WAKEKILL | __TASK_TRACED;
455 	}
456 	signal_wake_up_state(t, state);
457 }
ptrace_signal_wake_up(struct task_struct * t,bool resume)458 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
459 {
460 	unsigned int state = 0;
461 	if (resume) {
462 		t->jobctl &= ~JOBCTL_TRACED;
463 		state = __TASK_TRACED;
464 	}
465 	signal_wake_up_state(t, state);
466 }
467 
468 void task_join_group_stop(struct task_struct *task);
469 
470 #ifdef TIF_RESTORE_SIGMASK
471 /*
472  * Legacy restore_sigmask accessors.  These are inefficient on
473  * SMP architectures because they require atomic operations.
474  */
475 
476 /**
477  * set_restore_sigmask() - make sure saved_sigmask processing gets done
478  *
479  * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
480  * will run before returning to user mode, to process the flag.  For
481  * all callers, TIF_SIGPENDING is already set or it's no harm to set
482  * it.  TIF_RESTORE_SIGMASK need not be in the set of bits that the
483  * arch code will notice on return to user mode, in case those bits
484  * are scarce.  We set TIF_SIGPENDING here to ensure that the arch
485  * signal code always gets run when TIF_RESTORE_SIGMASK is set.
486  */
set_restore_sigmask(void)487 static inline void set_restore_sigmask(void)
488 {
489 	set_thread_flag(TIF_RESTORE_SIGMASK);
490 }
491 
clear_tsk_restore_sigmask(struct task_struct * task)492 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
493 {
494 	clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
495 }
496 
clear_restore_sigmask(void)497 static inline void clear_restore_sigmask(void)
498 {
499 	clear_thread_flag(TIF_RESTORE_SIGMASK);
500 }
test_tsk_restore_sigmask(struct task_struct * task)501 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
502 {
503 	return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
504 }
test_restore_sigmask(void)505 static inline bool test_restore_sigmask(void)
506 {
507 	return test_thread_flag(TIF_RESTORE_SIGMASK);
508 }
test_and_clear_restore_sigmask(void)509 static inline bool test_and_clear_restore_sigmask(void)
510 {
511 	return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
512 }
513 
514 #else	/* TIF_RESTORE_SIGMASK */
515 
516 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
set_restore_sigmask(void)517 static inline void set_restore_sigmask(void)
518 {
519 	current->restore_sigmask = true;
520 }
clear_tsk_restore_sigmask(struct task_struct * task)521 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
522 {
523 	task->restore_sigmask = false;
524 }
clear_restore_sigmask(void)525 static inline void clear_restore_sigmask(void)
526 {
527 	current->restore_sigmask = false;
528 }
test_restore_sigmask(void)529 static inline bool test_restore_sigmask(void)
530 {
531 	return current->restore_sigmask;
532 }
test_tsk_restore_sigmask(struct task_struct * task)533 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
534 {
535 	return task->restore_sigmask;
536 }
test_and_clear_restore_sigmask(void)537 static inline bool test_and_clear_restore_sigmask(void)
538 {
539 	if (!current->restore_sigmask)
540 		return false;
541 	current->restore_sigmask = false;
542 	return true;
543 }
544 #endif
545 
restore_saved_sigmask(void)546 static inline void restore_saved_sigmask(void)
547 {
548 	if (test_and_clear_restore_sigmask())
549 		__set_current_blocked(&current->saved_sigmask);
550 }
551 
552 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
553 
restore_saved_sigmask_unless(bool interrupted)554 static inline void restore_saved_sigmask_unless(bool interrupted)
555 {
556 	if (interrupted)
557 		WARN_ON(!signal_pending(current));
558 	else
559 		restore_saved_sigmask();
560 }
561 
sigmask_to_save(void)562 static inline sigset_t *sigmask_to_save(void)
563 {
564 	sigset_t *res = &current->blocked;
565 	if (unlikely(test_restore_sigmask()))
566 		res = &current->saved_sigmask;
567 	return res;
568 }
569 
kill_cad_pid(int sig,int priv)570 static inline int kill_cad_pid(int sig, int priv)
571 {
572 	return kill_pid(cad_pid, sig, priv);
573 }
574 
575 /* These can be the second arg to send_sig_info/send_group_sig_info.  */
576 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
577 #define SEND_SIG_PRIV	((struct kernel_siginfo *) 1)
578 
__on_sig_stack(unsigned long sp)579 static inline int __on_sig_stack(unsigned long sp)
580 {
581 #ifdef CONFIG_STACK_GROWSUP
582 	return sp >= current->sas_ss_sp &&
583 		sp - current->sas_ss_sp < current->sas_ss_size;
584 #else
585 	return sp > current->sas_ss_sp &&
586 		sp - current->sas_ss_sp <= current->sas_ss_size;
587 #endif
588 }
589 
590 /*
591  * True if we are on the alternate signal stack.
592  */
on_sig_stack(unsigned long sp)593 static inline int on_sig_stack(unsigned long sp)
594 {
595 	/*
596 	 * If the signal stack is SS_AUTODISARM then, by construction, we
597 	 * can't be on the signal stack unless user code deliberately set
598 	 * SS_AUTODISARM when we were already on it.
599 	 *
600 	 * This improves reliability: if user state gets corrupted such that
601 	 * the stack pointer points very close to the end of the signal stack,
602 	 * then this check will enable the signal to be handled anyway.
603 	 */
604 	if (current->sas_ss_flags & SS_AUTODISARM)
605 		return 0;
606 
607 	return __on_sig_stack(sp);
608 }
609 
sas_ss_flags(unsigned long sp)610 static inline int sas_ss_flags(unsigned long sp)
611 {
612 	if (!current->sas_ss_size)
613 		return SS_DISABLE;
614 
615 	return on_sig_stack(sp) ? SS_ONSTACK : 0;
616 }
617 
sas_ss_reset(struct task_struct * p)618 static inline void sas_ss_reset(struct task_struct *p)
619 {
620 	p->sas_ss_sp = 0;
621 	p->sas_ss_size = 0;
622 	p->sas_ss_flags = SS_DISABLE;
623 }
624 
sigsp(unsigned long sp,struct ksignal * ksig)625 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
626 {
627 	if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
628 #ifdef CONFIG_STACK_GROWSUP
629 		return current->sas_ss_sp;
630 #else
631 		return current->sas_ss_sp + current->sas_ss_size;
632 #endif
633 	return sp;
634 }
635 
636 extern void __cleanup_sighand(struct sighand_struct *);
637 extern void flush_itimer_signals(void);
638 
639 #define tasklist_empty() \
640 	list_empty(&init_task.tasks)
641 
642 #define next_task(p) \
643 	list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
644 
645 #define for_each_process(p) \
646 	for (p = &init_task ; (p = next_task(p)) != &init_task ; )
647 
648 extern bool current_is_single_threaded(void);
649 
650 /*
651  * Careful: do_each_thread/while_each_thread is a double loop so
652  *          'break' will not work as expected - use goto instead.
653  */
654 #define do_each_thread(g, t) \
655 	for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
656 
657 #define while_each_thread(g, t) \
658 	while ((t = next_thread(t)) != g)
659 
660 #define __for_each_thread(signal, t)	\
661 	list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)
662 
663 #define for_each_thread(p, t)		\
664 	__for_each_thread((p)->signal, t)
665 
666 /* Careful: this is a double loop, 'break' won't work as expected. */
667 #define for_each_process_thread(p, t)	\
668 	for_each_process(p) for_each_thread(p, t)
669 
670 typedef int (*proc_visitor)(struct task_struct *p, void *data);
671 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
672 
673 static inline
task_pid_type(struct task_struct * task,enum pid_type type)674 struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
675 {
676 	struct pid *pid;
677 	if (type == PIDTYPE_PID)
678 		pid = task_pid(task);
679 	else
680 		pid = task->signal->pids[type];
681 	return pid;
682 }
683 
task_tgid(struct task_struct * task)684 static inline struct pid *task_tgid(struct task_struct *task)
685 {
686 	return task->signal->pids[PIDTYPE_TGID];
687 }
688 
689 /*
690  * Without tasklist or RCU lock it is not safe to dereference
691  * the result of task_pgrp/task_session even if task == current,
692  * we can race with another thread doing sys_setsid/sys_setpgid.
693  */
task_pgrp(struct task_struct * task)694 static inline struct pid *task_pgrp(struct task_struct *task)
695 {
696 	return task->signal->pids[PIDTYPE_PGID];
697 }
698 
task_session(struct task_struct * task)699 static inline struct pid *task_session(struct task_struct *task)
700 {
701 	return task->signal->pids[PIDTYPE_SID];
702 }
703 
get_nr_threads(struct task_struct * task)704 static inline int get_nr_threads(struct task_struct *task)
705 {
706 	return task->signal->nr_threads;
707 }
708 
thread_group_leader(struct task_struct * p)709 static inline bool thread_group_leader(struct task_struct *p)
710 {
711 	return p->exit_signal >= 0;
712 }
713 
714 static inline
same_thread_group(struct task_struct * p1,struct task_struct * p2)715 bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
716 {
717 	return p1->signal == p2->signal;
718 }
719 
next_thread(const struct task_struct * p)720 static inline struct task_struct *next_thread(const struct task_struct *p)
721 {
722 	return list_entry_rcu(p->thread_group.next,
723 			      struct task_struct, thread_group);
724 }
725 
thread_group_empty(struct task_struct * p)726 static inline int thread_group_empty(struct task_struct *p)
727 {
728 	return list_empty(&p->thread_group);
729 }
730 
731 #define delay_group_leader(p) \
732 		(thread_group_leader(p) && !thread_group_empty(p))
733 
734 extern bool thread_group_exited(struct pid *pid);
735 
736 extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
737 							unsigned long *flags);
738 
lock_task_sighand(struct task_struct * task,unsigned long * flags)739 static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
740 						       unsigned long *flags)
741 {
742 	struct sighand_struct *ret;
743 
744 	ret = __lock_task_sighand(task, flags);
745 	(void)__cond_lock(&task->sighand->siglock, ret);
746 	return ret;
747 }
748 
unlock_task_sighand(struct task_struct * task,unsigned long * flags)749 static inline void unlock_task_sighand(struct task_struct *task,
750 						unsigned long *flags)
751 {
752 	spin_unlock_irqrestore(&task->sighand->siglock, *flags);
753 }
754 
755 #ifdef CONFIG_LOCKDEP
756 extern void lockdep_assert_task_sighand_held(struct task_struct *task);
757 #else
lockdep_assert_task_sighand_held(struct task_struct * task)758 static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { }
759 #endif
760 
task_rlimit(const struct task_struct * task,unsigned int limit)761 static inline unsigned long task_rlimit(const struct task_struct *task,
762 		unsigned int limit)
763 {
764 	return READ_ONCE(task->signal->rlim[limit].rlim_cur);
765 }
766 
task_rlimit_max(const struct task_struct * task,unsigned int limit)767 static inline unsigned long task_rlimit_max(const struct task_struct *task,
768 		unsigned int limit)
769 {
770 	return READ_ONCE(task->signal->rlim[limit].rlim_max);
771 }
772 
rlimit(unsigned int limit)773 static inline unsigned long rlimit(unsigned int limit)
774 {
775 	return task_rlimit(current, limit);
776 }
777 
rlimit_max(unsigned int limit)778 static inline unsigned long rlimit_max(unsigned int limit)
779 {
780 	return task_rlimit_max(current, limit);
781 }
782 
783 #endif /* _LINUX_SCHED_SIGNAL_H */
784