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
136 #ifdef CONFIG_POSIX_TIMERS
137
138 /* POSIX.1b Interval Timers */
139 unsigned int next_posix_timer_id;
140 struct hlist_head posix_timers;
141 struct hlist_head ignored_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 } __randomize_layout;
251
252 /*
253 * Bits in flags field of signal_struct.
254 */
255 #define SIGNAL_STOP_STOPPED 0x00000001 /* job control stop in effect */
256 #define SIGNAL_STOP_CONTINUED 0x00000002 /* SIGCONT since WCONTINUED reap */
257 #define SIGNAL_GROUP_EXIT 0x00000004 /* group exit in progress */
258 /*
259 * Pending notifications to parent.
260 */
261 #define SIGNAL_CLD_STOPPED 0x00000010
262 #define SIGNAL_CLD_CONTINUED 0x00000020
263 #define SIGNAL_CLD_MASK (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
264
265 #define SIGNAL_UNKILLABLE 0x00000040 /* for init: ignore fatal signals */
266
267 #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
268 SIGNAL_STOP_CONTINUED)
269
signal_set_stop_flags(struct signal_struct * sig,unsigned int flags)270 static inline void signal_set_stop_flags(struct signal_struct *sig,
271 unsigned int flags)
272 {
273 WARN_ON(sig->flags & SIGNAL_GROUP_EXIT);
274 sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
275 }
276
277 extern void flush_signals(struct task_struct *);
278 extern void ignore_signals(struct task_struct *);
279 extern void flush_signal_handlers(struct task_struct *, int force_default);
280 extern int dequeue_signal(sigset_t *mask, kernel_siginfo_t *info, enum pid_type *type);
281
kernel_dequeue_signal(void)282 static inline int kernel_dequeue_signal(void)
283 {
284 struct task_struct *task = current;
285 kernel_siginfo_t __info;
286 enum pid_type __type;
287 int ret;
288
289 spin_lock_irq(&task->sighand->siglock);
290 ret = dequeue_signal(&task->blocked, &__info, &__type);
291 spin_unlock_irq(&task->sighand->siglock);
292
293 return ret;
294 }
295
kernel_signal_stop(void)296 static inline void kernel_signal_stop(void)
297 {
298 spin_lock_irq(¤t->sighand->siglock);
299 if (current->jobctl & JOBCTL_STOP_DEQUEUED) {
300 current->jobctl |= JOBCTL_STOPPED;
301 set_special_state(TASK_STOPPED);
302 }
303 spin_unlock_irq(¤t->sighand->siglock);
304
305 schedule();
306 }
307
308 int force_sig_fault_to_task(int sig, int code, void __user *addr,
309 struct task_struct *t);
310 int force_sig_fault(int sig, int code, void __user *addr);
311 int send_sig_fault(int sig, int code, void __user *addr, struct task_struct *t);
312
313 int force_sig_mceerr(int code, void __user *, short);
314 int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
315
316 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
317 int force_sig_pkuerr(void __user *addr, u32 pkey);
318 int send_sig_perf(void __user *addr, u32 type, u64 sig_data);
319
320 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
321 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
322 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
323 struct task_struct *t);
324 int force_sig_seccomp(int syscall, int reason, bool force_coredump);
325
326 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
327 extern void force_sigsegv(int sig);
328 extern int force_sig_info(struct kernel_siginfo *);
329 extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
330 extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
331 extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
332 const struct cred *);
333 extern int kill_pgrp(struct pid *pid, int sig, int priv);
334 extern int kill_pid(struct pid *pid, int sig, int priv);
335 extern __must_check bool do_notify_parent(struct task_struct *, int);
336 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
337 extern void force_sig(int);
338 extern void force_fatal_sig(int);
339 extern void force_exit_sig(int);
340 extern int send_sig(int, struct task_struct *, int);
341 extern int zap_other_threads(struct task_struct *p);
342 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
343
clear_notify_signal(void)344 static inline void clear_notify_signal(void)
345 {
346 clear_thread_flag(TIF_NOTIFY_SIGNAL);
347 smp_mb__after_atomic();
348 }
349
350 /*
351 * Returns 'true' if kick_process() is needed to force a transition from
352 * user -> kernel to guarantee expedient run of TWA_SIGNAL based task_work.
353 */
__set_notify_signal(struct task_struct * task)354 static inline bool __set_notify_signal(struct task_struct *task)
355 {
356 return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) &&
357 !wake_up_state(task, TASK_INTERRUPTIBLE);
358 }
359
360 /*
361 * Called to break out of interruptible wait loops, and enter the
362 * exit_to_user_mode_loop().
363 */
set_notify_signal(struct task_struct * task)364 static inline void set_notify_signal(struct task_struct *task)
365 {
366 if (__set_notify_signal(task))
367 kick_process(task);
368 }
369
restart_syscall(void)370 static inline int restart_syscall(void)
371 {
372 set_tsk_thread_flag(current, TIF_SIGPENDING);
373 return -ERESTARTNOINTR;
374 }
375
task_sigpending(struct task_struct * p)376 static inline int task_sigpending(struct task_struct *p)
377 {
378 return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
379 }
380
signal_pending(struct task_struct * p)381 static inline int signal_pending(struct task_struct *p)
382 {
383 /*
384 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
385 * behavior in terms of ensuring that we break out of wait loops
386 * so that notify signal callbacks can be processed.
387 */
388 if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
389 return 1;
390 return task_sigpending(p);
391 }
392
__fatal_signal_pending(struct task_struct * p)393 static inline int __fatal_signal_pending(struct task_struct *p)
394 {
395 return unlikely(sigismember(&p->pending.signal, SIGKILL));
396 }
397
fatal_signal_pending(struct task_struct * p)398 static inline int fatal_signal_pending(struct task_struct *p)
399 {
400 return task_sigpending(p) && __fatal_signal_pending(p);
401 }
402
signal_pending_state(unsigned int state,struct task_struct * p)403 static inline int signal_pending_state(unsigned int state, struct task_struct *p)
404 {
405 if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
406 return 0;
407 if (!signal_pending(p))
408 return 0;
409
410 return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
411 }
412
413 /*
414 * This should only be used in fault handlers to decide whether we
415 * should stop the current fault routine to handle the signals
416 * instead, especially with the case where we've got interrupted with
417 * a VM_FAULT_RETRY.
418 */
fault_signal_pending(vm_fault_t fault_flags,struct pt_regs * regs)419 static inline bool fault_signal_pending(vm_fault_t fault_flags,
420 struct pt_regs *regs)
421 {
422 return unlikely((fault_flags & VM_FAULT_RETRY) &&
423 (fatal_signal_pending(current) ||
424 (user_mode(regs) && signal_pending(current))));
425 }
426
427 /*
428 * Reevaluate whether the task has signals pending delivery.
429 * Wake the task if so.
430 * This is required every time the blocked sigset_t changes.
431 * callers must hold sighand->siglock.
432 */
433 extern void recalc_sigpending(void);
434 extern void calculate_sigpending(void);
435
436 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
437
signal_wake_up(struct task_struct * t,bool fatal)438 static inline void signal_wake_up(struct task_struct *t, bool fatal)
439 {
440 unsigned int state = 0;
441 if (fatal && !(t->jobctl & JOBCTL_PTRACE_FROZEN)) {
442 t->jobctl &= ~(JOBCTL_STOPPED | JOBCTL_TRACED);
443 state = TASK_WAKEKILL | __TASK_TRACED;
444 }
445 signal_wake_up_state(t, state);
446 }
ptrace_signal_wake_up(struct task_struct * t,bool resume)447 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
448 {
449 unsigned int state = 0;
450 if (resume) {
451 t->jobctl &= ~JOBCTL_TRACED;
452 state = __TASK_TRACED;
453 }
454 signal_wake_up_state(t, state);
455 }
456
457 void task_join_group_stop(struct task_struct *task);
458
459 #ifdef TIF_RESTORE_SIGMASK
460 /*
461 * Legacy restore_sigmask accessors. These are inefficient on
462 * SMP architectures because they require atomic operations.
463 */
464
465 /**
466 * set_restore_sigmask() - make sure saved_sigmask processing gets done
467 *
468 * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
469 * will run before returning to user mode, to process the flag. For
470 * all callers, TIF_SIGPENDING is already set or it's no harm to set
471 * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the
472 * arch code will notice on return to user mode, in case those bits
473 * are scarce. We set TIF_SIGPENDING here to ensure that the arch
474 * signal code always gets run when TIF_RESTORE_SIGMASK is set.
475 */
set_restore_sigmask(void)476 static inline void set_restore_sigmask(void)
477 {
478 set_thread_flag(TIF_RESTORE_SIGMASK);
479 }
480
clear_tsk_restore_sigmask(struct task_struct * task)481 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
482 {
483 clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
484 }
485
clear_restore_sigmask(void)486 static inline void clear_restore_sigmask(void)
487 {
488 clear_thread_flag(TIF_RESTORE_SIGMASK);
489 }
test_tsk_restore_sigmask(struct task_struct * task)490 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
491 {
492 return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
493 }
test_restore_sigmask(void)494 static inline bool test_restore_sigmask(void)
495 {
496 return test_thread_flag(TIF_RESTORE_SIGMASK);
497 }
test_and_clear_restore_sigmask(void)498 static inline bool test_and_clear_restore_sigmask(void)
499 {
500 return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
501 }
502
503 #else /* TIF_RESTORE_SIGMASK */
504
505 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
set_restore_sigmask(void)506 static inline void set_restore_sigmask(void)
507 {
508 current->restore_sigmask = true;
509 }
clear_tsk_restore_sigmask(struct task_struct * task)510 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
511 {
512 task->restore_sigmask = false;
513 }
clear_restore_sigmask(void)514 static inline void clear_restore_sigmask(void)
515 {
516 current->restore_sigmask = false;
517 }
test_restore_sigmask(void)518 static inline bool test_restore_sigmask(void)
519 {
520 return current->restore_sigmask;
521 }
test_tsk_restore_sigmask(struct task_struct * task)522 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
523 {
524 return task->restore_sigmask;
525 }
test_and_clear_restore_sigmask(void)526 static inline bool test_and_clear_restore_sigmask(void)
527 {
528 if (!current->restore_sigmask)
529 return false;
530 current->restore_sigmask = false;
531 return true;
532 }
533 #endif
534
restore_saved_sigmask(void)535 static inline void restore_saved_sigmask(void)
536 {
537 if (test_and_clear_restore_sigmask())
538 __set_current_blocked(¤t->saved_sigmask);
539 }
540
541 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
542
restore_saved_sigmask_unless(bool interrupted)543 static inline void restore_saved_sigmask_unless(bool interrupted)
544 {
545 if (interrupted)
546 WARN_ON(!signal_pending(current));
547 else
548 restore_saved_sigmask();
549 }
550
sigmask_to_save(void)551 static inline sigset_t *sigmask_to_save(void)
552 {
553 sigset_t *res = ¤t->blocked;
554 if (unlikely(test_restore_sigmask()))
555 res = ¤t->saved_sigmask;
556 return res;
557 }
558
kill_cad_pid(int sig,int priv)559 static inline int kill_cad_pid(int sig, int priv)
560 {
561 return kill_pid(cad_pid, sig, priv);
562 }
563
564 /* These can be the second arg to send_sig_info/send_group_sig_info. */
565 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
566 #define SEND_SIG_PRIV ((struct kernel_siginfo *) 1)
567
__on_sig_stack(unsigned long sp)568 static inline int __on_sig_stack(unsigned long sp)
569 {
570 #ifdef CONFIG_STACK_GROWSUP
571 return sp >= current->sas_ss_sp &&
572 sp - current->sas_ss_sp < current->sas_ss_size;
573 #else
574 return sp > current->sas_ss_sp &&
575 sp - current->sas_ss_sp <= current->sas_ss_size;
576 #endif
577 }
578
579 /*
580 * True if we are on the alternate signal stack.
581 */
on_sig_stack(unsigned long sp)582 static inline int on_sig_stack(unsigned long sp)
583 {
584 /*
585 * If the signal stack is SS_AUTODISARM then, by construction, we
586 * can't be on the signal stack unless user code deliberately set
587 * SS_AUTODISARM when we were already on it.
588 *
589 * This improves reliability: if user state gets corrupted such that
590 * the stack pointer points very close to the end of the signal stack,
591 * then this check will enable the signal to be handled anyway.
592 */
593 if (current->sas_ss_flags & SS_AUTODISARM)
594 return 0;
595
596 return __on_sig_stack(sp);
597 }
598
sas_ss_flags(unsigned long sp)599 static inline int sas_ss_flags(unsigned long sp)
600 {
601 if (!current->sas_ss_size)
602 return SS_DISABLE;
603
604 return on_sig_stack(sp) ? SS_ONSTACK : 0;
605 }
606
sas_ss_reset(struct task_struct * p)607 static inline void sas_ss_reset(struct task_struct *p)
608 {
609 p->sas_ss_sp = 0;
610 p->sas_ss_size = 0;
611 p->sas_ss_flags = SS_DISABLE;
612 }
613
sigsp(unsigned long sp,struct ksignal * ksig)614 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
615 {
616 if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
617 #ifdef CONFIG_STACK_GROWSUP
618 return current->sas_ss_sp;
619 #else
620 return current->sas_ss_sp + current->sas_ss_size;
621 #endif
622 return sp;
623 }
624
625 extern void __cleanup_sighand(struct sighand_struct *);
626 extern void flush_itimer_signals(void);
627
628 #define tasklist_empty() \
629 list_empty(&init_task.tasks)
630
631 #define next_task(p) \
632 list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
633
634 #define for_each_process(p) \
635 for (p = &init_task ; (p = next_task(p)) != &init_task ; )
636
637 extern bool current_is_single_threaded(void);
638
639 /*
640 * Without tasklist/siglock it is only rcu-safe if g can't exit/exec,
641 * otherwise next_thread(t) will never reach g after list_del_rcu(g).
642 */
643 #define while_each_thread(g, t) \
644 while ((t = next_thread(t)) != g)
645
646 #define for_other_threads(p, t) \
647 for (t = p; (t = next_thread(t)) != p; )
648
649 #define __for_each_thread(signal, t) \
650 list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node, \
651 lockdep_is_held(&tasklist_lock))
652
653 #define for_each_thread(p, t) \
654 __for_each_thread((p)->signal, t)
655
656 /* Careful: this is a double loop, 'break' won't work as expected. */
657 #define for_each_process_thread(p, t) \
658 for_each_process(p) for_each_thread(p, t)
659
660 typedef int (*proc_visitor)(struct task_struct *p, void *data);
661 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
662
663 static inline
task_pid_type(struct task_struct * task,enum pid_type type)664 struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
665 {
666 struct pid *pid;
667 if (type == PIDTYPE_PID)
668 pid = task_pid(task);
669 else
670 pid = task->signal->pids[type];
671 return pid;
672 }
673
task_tgid(struct task_struct * task)674 static inline struct pid *task_tgid(struct task_struct *task)
675 {
676 return task->signal->pids[PIDTYPE_TGID];
677 }
678
679 /*
680 * Without tasklist or RCU lock it is not safe to dereference
681 * the result of task_pgrp/task_session even if task == current,
682 * we can race with another thread doing sys_setsid/sys_setpgid.
683 */
task_pgrp(struct task_struct * task)684 static inline struct pid *task_pgrp(struct task_struct *task)
685 {
686 return task->signal->pids[PIDTYPE_PGID];
687 }
688
task_session(struct task_struct * task)689 static inline struct pid *task_session(struct task_struct *task)
690 {
691 return task->signal->pids[PIDTYPE_SID];
692 }
693
get_nr_threads(struct task_struct * task)694 static inline int get_nr_threads(struct task_struct *task)
695 {
696 return task->signal->nr_threads;
697 }
698
thread_group_leader(struct task_struct * p)699 static inline bool thread_group_leader(struct task_struct *p)
700 {
701 return p->exit_signal >= 0;
702 }
703
704 static inline
same_thread_group(struct task_struct * p1,struct task_struct * p2)705 bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
706 {
707 return p1->signal == p2->signal;
708 }
709
710 /*
711 * returns NULL if p is the last thread in the thread group
712 */
__next_thread(struct task_struct * p)713 static inline struct task_struct *__next_thread(struct task_struct *p)
714 {
715 return list_next_or_null_rcu(&p->signal->thread_head,
716 &p->thread_node,
717 struct task_struct,
718 thread_node);
719 }
720
next_thread(struct task_struct * p)721 static inline struct task_struct *next_thread(struct task_struct *p)
722 {
723 return __next_thread(p) ?: p->group_leader;
724 }
725
thread_group_empty(struct task_struct * p)726 static inline int thread_group_empty(struct task_struct *p)
727 {
728 return thread_group_leader(p) &&
729 list_is_last(&p->thread_node, &p->signal->thread_head);
730 }
731
732 #define delay_group_leader(p) \
733 (thread_group_leader(p) && !thread_group_empty(p))
734
735 extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
736 unsigned long *flags);
737
lock_task_sighand(struct task_struct * task,unsigned long * flags)738 static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
739 unsigned long *flags)
740 {
741 struct sighand_struct *ret;
742
743 ret = __lock_task_sighand(task, flags);
744 (void)__cond_lock(&task->sighand->siglock, ret);
745 return ret;
746 }
747
unlock_task_sighand(struct task_struct * task,unsigned long * flags)748 static inline void unlock_task_sighand(struct task_struct *task,
749 unsigned long *flags)
750 {
751 spin_unlock_irqrestore(&task->sighand->siglock, *flags);
752 }
753
754 #ifdef CONFIG_LOCKDEP
755 extern void lockdep_assert_task_sighand_held(struct task_struct *task);
756 #else
lockdep_assert_task_sighand_held(struct task_struct * task)757 static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { }
758 #endif
759
task_rlimit(const struct task_struct * task,unsigned int limit)760 static inline unsigned long task_rlimit(const struct task_struct *task,
761 unsigned int limit)
762 {
763 return READ_ONCE(task->signal->rlim[limit].rlim_cur);
764 }
765
task_rlimit_max(const struct task_struct * task,unsigned int limit)766 static inline unsigned long task_rlimit_max(const struct task_struct *task,
767 unsigned int limit)
768 {
769 return READ_ONCE(task->signal->rlim[limit].rlim_max);
770 }
771
rlimit(unsigned int limit)772 static inline unsigned long rlimit(unsigned int limit)
773 {
774 return task_rlimit(current, limit);
775 }
776
rlimit_max(unsigned int limit)777 static inline unsigned long rlimit_max(unsigned int limit)
778 {
779 return task_rlimit_max(current, limit);
780 }
781
782 #endif /* _LINUX_SCHED_SIGNAL_H */
783