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 #include <linux/android_kabi.h>
17
18 /*
19 * Types defining task->signal and task->sighand and APIs using them:
20 */
21
22 struct sighand_struct {
23 spinlock_t siglock;
24 refcount_t count;
25 wait_queue_head_t signalfd_wqh;
26 struct k_sigaction action[_NSIG];
27 };
28
29 /*
30 * Per-process accounting stats:
31 */
32 struct pacct_struct {
33 int ac_flag;
34 long ac_exitcode;
35 unsigned long ac_mem;
36 u64 ac_utime, ac_stime;
37 unsigned long ac_minflt, ac_majflt;
38 };
39
40 struct cpu_itimer {
41 u64 expires;
42 u64 incr;
43 };
44
45 /*
46 * This is the atomic variant of task_cputime, which can be used for
47 * storing and updating task_cputime statistics without locking.
48 */
49 struct task_cputime_atomic {
50 atomic64_t utime;
51 atomic64_t stime;
52 atomic64_t sum_exec_runtime;
53 };
54
55 #define INIT_CPUTIME_ATOMIC \
56 (struct task_cputime_atomic) { \
57 .utime = ATOMIC64_INIT(0), \
58 .stime = ATOMIC64_INIT(0), \
59 .sum_exec_runtime = ATOMIC64_INIT(0), \
60 }
61 /**
62 * struct thread_group_cputimer - thread group interval timer counts
63 * @cputime_atomic: atomic thread group interval timers.
64 *
65 * This structure contains the version of task_cputime, above, that is
66 * used for thread group CPU timer calculations.
67 */
68 struct thread_group_cputimer {
69 struct task_cputime_atomic cputime_atomic;
70 };
71
72 struct multiprocess_signals {
73 sigset_t signal;
74 struct hlist_node node;
75 };
76
77 struct core_thread {
78 struct task_struct *task;
79 struct core_thread *next;
80 };
81
82 struct core_state {
83 atomic_t nr_threads;
84 struct core_thread dumper;
85 struct completion startup;
86 };
87
88 /*
89 * NOTE! "signal_struct" does not have its own
90 * locking, because a shared signal_struct always
91 * implies a shared sighand_struct, so locking
92 * sighand_struct is always a proper superset of
93 * the locking of signal_struct.
94 */
95 struct signal_struct {
96 refcount_t sigcnt;
97 atomic_t live;
98 int nr_threads;
99 int quick_threads;
100 struct list_head thread_head;
101
102 wait_queue_head_t wait_chldexit; /* for wait4() */
103
104 /* current thread group signal load-balancing target: */
105 struct task_struct *curr_target;
106
107 /* shared signal handling: */
108 struct sigpending shared_pending;
109
110 /* For collecting multiprocess signals during fork */
111 struct hlist_head multiprocess;
112
113 /* thread group exit support */
114 int group_exit_code;
115 /* notify group_exec_task when notify_count is less or equal to 0 */
116 int notify_count;
117 struct task_struct *group_exec_task;
118
119 /* thread group stop support, overloads group_exit_code too */
120 int group_stop_count;
121 unsigned int flags; /* see SIGNAL_* flags below */
122
123 struct core_state *core_state; /* coredumping support */
124
125 /*
126 * PR_SET_CHILD_SUBREAPER marks a process, like a service
127 * manager, to re-parent orphan (double-forking) child processes
128 * to this process instead of 'init'. The service manager is
129 * able to receive SIGCHLD signals and is able to investigate
130 * the process until it calls wait(). All children of this
131 * process will inherit a flag if they should look for a
132 * child_subreaper process at exit.
133 */
134 unsigned int is_child_subreaper:1;
135 unsigned int has_child_subreaper:1;
136
137 #ifdef CONFIG_POSIX_TIMERS
138
139 /* POSIX.1b Interval Timers */
140 unsigned int next_posix_timer_id;
141 struct hlist_head posix_timers;
142
143 /* ITIMER_REAL timer for the process */
144 struct hrtimer real_timer;
145 ktime_t it_real_incr;
146
147 /*
148 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
149 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
150 * values are defined to 0 and 1 respectively
151 */
152 struct cpu_itimer it[2];
153
154 /*
155 * Thread group totals for process CPU timers.
156 * See thread_group_cputimer(), et al, for details.
157 */
158 struct thread_group_cputimer cputimer;
159
160 #endif
161 /* Empty if CONFIG_POSIX_TIMERS=n */
162 struct posix_cputimers posix_cputimers;
163
164 /* PID/PID hash table linkage. */
165 struct pid *pids[PIDTYPE_MAX];
166
167 #ifdef CONFIG_NO_HZ_FULL
168 atomic_t tick_dep_mask;
169 #endif
170
171 struct pid *tty_old_pgrp;
172
173 /* boolean value for session group leader */
174 int leader;
175
176 struct tty_struct *tty; /* NULL if no tty */
177
178 #ifdef CONFIG_SCHED_AUTOGROUP
179 struct autogroup *autogroup;
180 #endif
181 /*
182 * Cumulative resource counters for dead threads in the group,
183 * and for reaped dead child processes forked by this group.
184 * Live threads maintain their own counters and add to these
185 * in __exit_signal, except for the group leader.
186 */
187 seqlock_t stats_lock;
188 u64 utime, stime, cutime, cstime;
189 u64 gtime;
190 u64 cgtime;
191 struct prev_cputime prev_cputime;
192 unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
193 unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
194 unsigned long inblock, oublock, cinblock, coublock;
195 unsigned long maxrss, cmaxrss;
196 struct task_io_accounting ioac;
197
198 /*
199 * Cumulative ns of schedule CPU time fo dead threads in the
200 * group, not including a zombie group leader, (This only differs
201 * from jiffies_to_ns(utime + stime) if sched_clock uses something
202 * other than jiffies.)
203 */
204 unsigned long long sum_sched_runtime;
205
206 /*
207 * We don't bother to synchronize most readers of this at all,
208 * because there is no reader checking a limit that actually needs
209 * to get both rlim_cur and rlim_max atomically, and either one
210 * alone is a single word that can safely be read normally.
211 * getrlimit/setrlimit use task_lock(current->group_leader) to
212 * protect this instead of the siglock, because they really
213 * have no need to disable irqs.
214 */
215 struct rlimit rlim[RLIM_NLIMITS];
216
217 #ifdef CONFIG_BSD_PROCESS_ACCT
218 struct pacct_struct pacct; /* per-process accounting information */
219 #endif
220 #ifdef CONFIG_TASKSTATS
221 struct taskstats *stats;
222 #endif
223 #ifdef CONFIG_AUDIT
224 unsigned audit_tty;
225 struct tty_audit_buf *tty_audit_buf;
226 #endif
227
228 /*
229 * Thread is the potential origin of an oom condition; kill first on
230 * oom
231 */
232 bool oom_flag_origin;
233 short oom_score_adj; /* OOM kill score adjustment */
234 short oom_score_adj_min; /* OOM kill score adjustment min value.
235 * Only settable by CAP_SYS_RESOURCE. */
236 struct mm_struct *oom_mm; /* recorded mm when the thread group got
237 * killed by the oom killer */
238
239 struct mutex cred_guard_mutex; /* guard against foreign influences on
240 * credential calculations
241 * (notably. ptrace)
242 * Deprecated do not use in new code.
243 * Use exec_update_lock instead.
244 */
245 struct rw_semaphore exec_update_lock; /* Held while task_struct is
246 * being updated during exec,
247 * and may have inconsistent
248 * permissions.
249 */
250 ANDROID_KABI_RESERVE(1);
251 ANDROID_KABI_RESERVE(2);
252 ANDROID_KABI_RESERVE(3);
253 ANDROID_KABI_RESERVE(4);
254 ANDROID_OEM_DATA(1);
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
signal_set_stop_flags(struct signal_struct * sig,unsigned int flags)275 static 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
282 extern void flush_signals(struct task_struct *);
283 extern void ignore_signals(struct task_struct *);
284 extern void flush_signal_handlers(struct task_struct *, int force_default);
285 extern int dequeue_signal(sigset_t *mask, kernel_siginfo_t *info, enum pid_type *type);
286
kernel_dequeue_signal(void)287 static 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
kernel_signal_stop(void)301 static inline void kernel_signal_stop(void)
302 {
303 spin_lock_irq(¤t->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(¤t->sighand->siglock);
309
310 schedule();
311 }
312
313 int force_sig_fault_to_task(int sig, int code, void __user *addr,
314 struct task_struct *t);
315 int force_sig_fault(int sig, int code, void __user *addr);
316 int send_sig_fault(int sig, int code, void __user *addr, struct task_struct *t);
317
318 int force_sig_mceerr(int code, void __user *, short);
319 int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
320
321 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
322 int force_sig_pkuerr(void __user *addr, u32 pkey);
323 int send_sig_perf(void __user *addr, u32 type, u64 sig_data);
324
325 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
326 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
327 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
328 struct task_struct *t);
329 int force_sig_seccomp(int syscall, int reason, bool force_coredump);
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 void force_fatal_sig(int);
344 extern void force_exit_sig(int);
345 extern int send_sig(int, struct task_struct *, int);
346 extern int zap_other_threads(struct task_struct *p);
347 extern struct sigqueue *sigqueue_alloc(void);
348 extern void sigqueue_free(struct sigqueue *);
349 extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
350 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
351
clear_notify_signal(void)352 static inline void clear_notify_signal(void)
353 {
354 clear_thread_flag(TIF_NOTIFY_SIGNAL);
355 smp_mb__after_atomic();
356 }
357
358 /*
359 * Returns 'true' if kick_process() is needed to force a transition from
360 * user -> kernel to guarantee expedient run of TWA_SIGNAL based task_work.
361 */
__set_notify_signal(struct task_struct * task)362 static inline bool __set_notify_signal(struct task_struct *task)
363 {
364 return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) &&
365 !wake_up_state(task, TASK_INTERRUPTIBLE);
366 }
367
368 /*
369 * Called to break out of interruptible wait loops, and enter the
370 * exit_to_user_mode_loop().
371 */
set_notify_signal(struct task_struct * task)372 static inline void set_notify_signal(struct task_struct *task)
373 {
374 if (__set_notify_signal(task))
375 kick_process(task);
376 }
377
restart_syscall(void)378 static inline int restart_syscall(void)
379 {
380 set_tsk_thread_flag(current, TIF_SIGPENDING);
381 return -ERESTARTNOINTR;
382 }
383
task_sigpending(struct task_struct * p)384 static inline int task_sigpending(struct task_struct *p)
385 {
386 return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
387 }
388
signal_pending(struct task_struct * p)389 static inline int signal_pending(struct task_struct *p)
390 {
391 /*
392 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
393 * behavior in terms of ensuring that we break out of wait loops
394 * so that notify signal callbacks can be processed.
395 */
396 if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
397 return 1;
398 return task_sigpending(p);
399 }
400
__fatal_signal_pending(struct task_struct * p)401 static inline int __fatal_signal_pending(struct task_struct *p)
402 {
403 return unlikely(sigismember(&p->pending.signal, SIGKILL));
404 }
405
fatal_signal_pending(struct task_struct * p)406 static inline int fatal_signal_pending(struct task_struct *p)
407 {
408 return task_sigpending(p) && __fatal_signal_pending(p);
409 }
410
signal_pending_state(unsigned int state,struct task_struct * p)411 static inline int signal_pending_state(unsigned int state, struct task_struct *p)
412 {
413 if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
414 return 0;
415 if (!signal_pending(p))
416 return 0;
417
418 return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
419 }
420
421 /*
422 * This should only be used in fault handlers to decide whether we
423 * should stop the current fault routine to handle the signals
424 * instead, especially with the case where we've got interrupted with
425 * a VM_FAULT_RETRY.
426 */
fault_signal_pending(vm_fault_t fault_flags,struct pt_regs * regs)427 static inline bool fault_signal_pending(vm_fault_t fault_flags,
428 struct pt_regs *regs)
429 {
430 return unlikely((fault_flags & VM_FAULT_RETRY) &&
431 (fatal_signal_pending(current) ||
432 (user_mode(regs) && signal_pending(current))));
433 }
434
435 /*
436 * Reevaluate whether the task has signals pending delivery.
437 * Wake the task if so.
438 * This is required every time the blocked sigset_t changes.
439 * callers must hold sighand->siglock.
440 */
441 extern void recalc_sigpending(void);
442 extern void calculate_sigpending(void);
443
444 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
445
signal_wake_up(struct task_struct * t,bool fatal)446 static inline void signal_wake_up(struct task_struct *t, bool fatal)
447 {
448 unsigned int state = 0;
449 if (fatal && !(t->jobctl & JOBCTL_PTRACE_FROZEN)) {
450 t->jobctl &= ~(JOBCTL_STOPPED | JOBCTL_TRACED);
451 state = TASK_WAKEKILL | __TASK_TRACED;
452 }
453 signal_wake_up_state(t, state);
454 }
ptrace_signal_wake_up(struct task_struct * t,bool resume)455 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
456 {
457 unsigned int state = 0;
458 if (resume) {
459 t->jobctl &= ~JOBCTL_TRACED;
460 state = __TASK_TRACED;
461 }
462 signal_wake_up_state(t, state);
463 }
464
465 void task_join_group_stop(struct task_struct *task);
466
467 #ifdef TIF_RESTORE_SIGMASK
468 /*
469 * Legacy restore_sigmask accessors. These are inefficient on
470 * SMP architectures because they require atomic operations.
471 */
472
473 /**
474 * set_restore_sigmask() - make sure saved_sigmask processing gets done
475 *
476 * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
477 * will run before returning to user mode, to process the flag. For
478 * all callers, TIF_SIGPENDING is already set or it's no harm to set
479 * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the
480 * arch code will notice on return to user mode, in case those bits
481 * are scarce. We set TIF_SIGPENDING here to ensure that the arch
482 * signal code always gets run when TIF_RESTORE_SIGMASK is set.
483 */
set_restore_sigmask(void)484 static inline void set_restore_sigmask(void)
485 {
486 set_thread_flag(TIF_RESTORE_SIGMASK);
487 }
488
clear_tsk_restore_sigmask(struct task_struct * task)489 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
490 {
491 clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
492 }
493
clear_restore_sigmask(void)494 static inline void clear_restore_sigmask(void)
495 {
496 clear_thread_flag(TIF_RESTORE_SIGMASK);
497 }
test_tsk_restore_sigmask(struct task_struct * task)498 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
499 {
500 return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
501 }
test_restore_sigmask(void)502 static inline bool test_restore_sigmask(void)
503 {
504 return test_thread_flag(TIF_RESTORE_SIGMASK);
505 }
test_and_clear_restore_sigmask(void)506 static inline bool test_and_clear_restore_sigmask(void)
507 {
508 return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
509 }
510
511 #else /* TIF_RESTORE_SIGMASK */
512
513 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
set_restore_sigmask(void)514 static inline void set_restore_sigmask(void)
515 {
516 current->restore_sigmask = true;
517 }
clear_tsk_restore_sigmask(struct task_struct * task)518 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
519 {
520 task->restore_sigmask = false;
521 }
clear_restore_sigmask(void)522 static inline void clear_restore_sigmask(void)
523 {
524 current->restore_sigmask = false;
525 }
test_restore_sigmask(void)526 static inline bool test_restore_sigmask(void)
527 {
528 return current->restore_sigmask;
529 }
test_tsk_restore_sigmask(struct task_struct * task)530 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
531 {
532 return task->restore_sigmask;
533 }
test_and_clear_restore_sigmask(void)534 static inline bool test_and_clear_restore_sigmask(void)
535 {
536 if (!current->restore_sigmask)
537 return false;
538 current->restore_sigmask = false;
539 return true;
540 }
541 #endif
542
restore_saved_sigmask(void)543 static inline void restore_saved_sigmask(void)
544 {
545 if (test_and_clear_restore_sigmask())
546 __set_current_blocked(¤t->saved_sigmask);
547 }
548
549 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
550
restore_saved_sigmask_unless(bool interrupted)551 static inline void restore_saved_sigmask_unless(bool interrupted)
552 {
553 if (interrupted)
554 WARN_ON(!signal_pending(current));
555 else
556 restore_saved_sigmask();
557 }
558
sigmask_to_save(void)559 static inline sigset_t *sigmask_to_save(void)
560 {
561 sigset_t *res = ¤t->blocked;
562 if (unlikely(test_restore_sigmask()))
563 res = ¤t->saved_sigmask;
564 return res;
565 }
566
kill_cad_pid(int sig,int priv)567 static inline int kill_cad_pid(int sig, int priv)
568 {
569 return kill_pid(cad_pid, sig, priv);
570 }
571
572 /* These can be the second arg to send_sig_info/send_group_sig_info. */
573 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
574 #define SEND_SIG_PRIV ((struct kernel_siginfo *) 1)
575
__on_sig_stack(unsigned long sp)576 static inline int __on_sig_stack(unsigned long sp)
577 {
578 #ifdef CONFIG_STACK_GROWSUP
579 return sp >= current->sas_ss_sp &&
580 sp - current->sas_ss_sp < current->sas_ss_size;
581 #else
582 return sp > current->sas_ss_sp &&
583 sp - current->sas_ss_sp <= current->sas_ss_size;
584 #endif
585 }
586
587 /*
588 * True if we are on the alternate signal stack.
589 */
on_sig_stack(unsigned long sp)590 static inline int on_sig_stack(unsigned long sp)
591 {
592 /*
593 * If the signal stack is SS_AUTODISARM then, by construction, we
594 * can't be on the signal stack unless user code deliberately set
595 * SS_AUTODISARM when we were already on it.
596 *
597 * This improves reliability: if user state gets corrupted such that
598 * the stack pointer points very close to the end of the signal stack,
599 * then this check will enable the signal to be handled anyway.
600 */
601 if (current->sas_ss_flags & SS_AUTODISARM)
602 return 0;
603
604 return __on_sig_stack(sp);
605 }
606
sas_ss_flags(unsigned long sp)607 static inline int sas_ss_flags(unsigned long sp)
608 {
609 if (!current->sas_ss_size)
610 return SS_DISABLE;
611
612 return on_sig_stack(sp) ? SS_ONSTACK : 0;
613 }
614
sas_ss_reset(struct task_struct * p)615 static inline void sas_ss_reset(struct task_struct *p)
616 {
617 p->sas_ss_sp = 0;
618 p->sas_ss_size = 0;
619 p->sas_ss_flags = SS_DISABLE;
620 }
621
sigsp(unsigned long sp,struct ksignal * ksig)622 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
623 {
624 if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
625 #ifdef CONFIG_STACK_GROWSUP
626 return current->sas_ss_sp;
627 #else
628 return current->sas_ss_sp + current->sas_ss_size;
629 #endif
630 return sp;
631 }
632
633 extern void __cleanup_sighand(struct sighand_struct *);
634 extern void flush_itimer_signals(void);
635
636 #define tasklist_empty() \
637 list_empty(&init_task.tasks)
638
639 #define next_task(p) \
640 list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
641
642 #define for_each_process(p) \
643 for (p = &init_task ; (p = next_task(p)) != &init_task ; )
644
645 extern bool current_is_single_threaded(void);
646
647 /*
648 * Without tasklist/siglock it is only rcu-safe if g can't exit/exec,
649 * otherwise next_thread(t) will never reach g after list_del_rcu(g).
650 */
651 #define while_each_thread(g, t) \
652 while ((t = next_thread(t)) != g)
653
654 #define for_other_threads(p, t) \
655 for (t = p; (t = next_thread(t)) != p; )
656
657 #define __for_each_thread(signal, t) \
658 list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node, \
659 lockdep_is_held(&tasklist_lock))
660
661 #define for_each_thread(p, t) \
662 __for_each_thread((p)->signal, t)
663
664 /* Careful: this is a double loop, 'break' won't work as expected. */
665 #define for_each_process_thread(p, t) \
666 for_each_process(p) for_each_thread(p, t)
667
668 typedef int (*proc_visitor)(struct task_struct *p, void *data);
669 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
670
671 static inline
task_pid_type(struct task_struct * task,enum pid_type type)672 struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
673 {
674 struct pid *pid;
675 if (type == PIDTYPE_PID)
676 pid = task_pid(task);
677 else
678 pid = task->signal->pids[type];
679 return pid;
680 }
681
task_tgid(struct task_struct * task)682 static inline struct pid *task_tgid(struct task_struct *task)
683 {
684 return task->signal->pids[PIDTYPE_TGID];
685 }
686
687 /*
688 * Without tasklist or RCU lock it is not safe to dereference
689 * the result of task_pgrp/task_session even if task == current,
690 * we can race with another thread doing sys_setsid/sys_setpgid.
691 */
task_pgrp(struct task_struct * task)692 static inline struct pid *task_pgrp(struct task_struct *task)
693 {
694 return task->signal->pids[PIDTYPE_PGID];
695 }
696
task_session(struct task_struct * task)697 static inline struct pid *task_session(struct task_struct *task)
698 {
699 return task->signal->pids[PIDTYPE_SID];
700 }
701
get_nr_threads(struct task_struct * task)702 static inline int get_nr_threads(struct task_struct *task)
703 {
704 return task->signal->nr_threads;
705 }
706
thread_group_leader(struct task_struct * p)707 static inline bool thread_group_leader(struct task_struct *p)
708 {
709 return p->exit_signal >= 0;
710 }
711
712 static inline
same_thread_group(struct task_struct * p1,struct task_struct * p2)713 bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
714 {
715 return p1->signal == p2->signal;
716 }
717
718 /*
719 * returns NULL if p is the last thread in the thread group
720 */
__next_thread(struct task_struct * p)721 static inline struct task_struct *__next_thread(struct task_struct *p)
722 {
723 return list_next_or_null_rcu(&p->signal->thread_head,
724 &p->thread_node,
725 struct task_struct,
726 thread_node);
727 }
728
next_thread(struct task_struct * p)729 static inline struct task_struct *next_thread(struct task_struct *p)
730 {
731 return __next_thread(p) ?: p->group_leader;
732 }
733
thread_group_empty(struct task_struct * p)734 static inline int thread_group_empty(struct task_struct *p)
735 {
736 return thread_group_leader(p) &&
737 list_is_last(&p->thread_node, &p->signal->thread_head);
738 }
739
740 #define delay_group_leader(p) \
741 (thread_group_leader(p) && !thread_group_empty(p))
742
743 extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
744 unsigned long *flags);
745
lock_task_sighand(struct task_struct * task,unsigned long * flags)746 static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
747 unsigned long *flags)
748 {
749 struct sighand_struct *ret;
750
751 ret = __lock_task_sighand(task, flags);
752 (void)__cond_lock(&task->sighand->siglock, ret);
753 return ret;
754 }
755
unlock_task_sighand(struct task_struct * task,unsigned long * flags)756 static inline void unlock_task_sighand(struct task_struct *task,
757 unsigned long *flags)
758 {
759 spin_unlock_irqrestore(&task->sighand->siglock, *flags);
760 }
761
762 #ifdef CONFIG_LOCKDEP
763 extern void lockdep_assert_task_sighand_held(struct task_struct *task);
764 #else
lockdep_assert_task_sighand_held(struct task_struct * task)765 static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { }
766 #endif
767
task_rlimit(const struct task_struct * task,unsigned int limit)768 static inline unsigned long task_rlimit(const struct task_struct *task,
769 unsigned int limit)
770 {
771 return READ_ONCE(task->signal->rlim[limit].rlim_cur);
772 }
773
task_rlimit_max(const struct task_struct * task,unsigned int limit)774 static inline unsigned long task_rlimit_max(const struct task_struct *task,
775 unsigned int limit)
776 {
777 return READ_ONCE(task->signal->rlim[limit].rlim_max);
778 }
779
rlimit(unsigned int limit)780 static inline unsigned long rlimit(unsigned int limit)
781 {
782 return task_rlimit(current, limit);
783 }
784
rlimit_max(unsigned int limit)785 static inline unsigned long rlimit_max(unsigned int limit)
786 {
787 return task_rlimit_max(current, limit);
788 }
789
790 #endif /* _LINUX_SCHED_SIGNAL_H */
791