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