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 #include <linux/android_kabi.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 list_head posix_timers;
141
142 /* ITIMER_REAL timer for the process */
143 struct hrtimer real_timer;
144 ktime_t it_real_incr;
145
146 /*
147 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
148 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
149 * values are defined to 0 and 1 respectively
150 */
151 struct cpu_itimer it[2];
152
153 /*
154 * Thread group totals for process CPU timers.
155 * See thread_group_cputimer(), et al, for details.
156 */
157 struct thread_group_cputimer cputimer;
158
159 #endif
160 /* Empty if CONFIG_POSIX_TIMERS=n */
161 struct posix_cputimers posix_cputimers;
162
163 /* PID/PID hash table linkage. */
164 struct pid *pids[PIDTYPE_MAX];
165
166 #ifdef CONFIG_NO_HZ_FULL
167 atomic_t tick_dep_mask;
168 #endif
169
170 struct pid *tty_old_pgrp;
171
172 /* boolean value for session group leader */
173 int leader;
174
175 struct tty_struct *tty; /* NULL if no tty */
176
177 #ifdef CONFIG_SCHED_AUTOGROUP
178 struct autogroup *autogroup;
179 #endif
180 /*
181 * Cumulative resource counters for dead threads in the group,
182 * and for reaped dead child processes forked by this group.
183 * Live threads maintain their own counters and add to these
184 * in __exit_signal, except for the group leader.
185 */
186 seqlock_t stats_lock;
187 u64 utime, stime, cutime, cstime;
188 u64 gtime;
189 u64 cgtime;
190 struct prev_cputime prev_cputime;
191 unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
192 unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
193 unsigned long inblock, oublock, cinblock, coublock;
194 unsigned long maxrss, cmaxrss;
195 struct task_io_accounting ioac;
196
197 /*
198 * Cumulative ns of schedule CPU time fo dead threads in the
199 * group, not including a zombie group leader, (This only differs
200 * from jiffies_to_ns(utime + stime) if sched_clock uses something
201 * other than jiffies.)
202 */
203 unsigned long long sum_sched_runtime;
204
205 /*
206 * We don't bother to synchronize most readers of this at all,
207 * because there is no reader checking a limit that actually needs
208 * to get both rlim_cur and rlim_max atomically, and either one
209 * alone is a single word that can safely be read normally.
210 * getrlimit/setrlimit use task_lock(current->group_leader) to
211 * protect this instead of the siglock, because they really
212 * have no need to disable irqs.
213 */
214 struct rlimit rlim[RLIM_NLIMITS];
215
216 #ifdef CONFIG_BSD_PROCESS_ACCT
217 struct pacct_struct pacct; /* per-process accounting information */
218 #endif
219 #ifdef CONFIG_TASKSTATS
220 struct taskstats *stats;
221 #endif
222 #ifdef CONFIG_AUDIT
223 unsigned audit_tty;
224 struct tty_audit_buf *tty_audit_buf;
225 #endif
226
227 /*
228 * Thread is the potential origin of an oom condition; kill first on
229 * oom
230 */
231 bool oom_flag_origin;
232 short oom_score_adj; /* OOM kill score adjustment */
233 short oom_score_adj_min; /* OOM kill score adjustment min value.
234 * Only settable by CAP_SYS_RESOURCE. */
235 struct mm_struct *oom_mm; /* recorded mm when the thread group got
236 * killed by the oom killer */
237
238 struct mutex cred_guard_mutex; /* guard against foreign influences on
239 * credential calculations
240 * (notably. ptrace)
241 * Deprecated do not use in new code.
242 * Use exec_update_lock instead.
243 */
244 struct rw_semaphore exec_update_lock; /* Held while task_struct is
245 * being updated during exec,
246 * and may have inconsistent
247 * permissions.
248 */
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(struct task_struct *task, sigset_t *mask,
286 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, &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 #ifdef __ia64__
314 # define ___ARCH_SI_IA64(_a1, _a2, _a3) , _a1, _a2, _a3
315 #else
316 # define ___ARCH_SI_IA64(_a1, _a2, _a3)
317 #endif
318
319 int force_sig_fault_to_task(int sig, int code, void __user *addr
320 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
321 , struct task_struct *t);
322 int force_sig_fault(int sig, int code, void __user *addr
323 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr));
324 int send_sig_fault(int sig, int code, void __user *addr
325 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
326 , struct task_struct *t);
327
328 int force_sig_mceerr(int code, void __user *, short);
329 int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
330
331 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
332 int force_sig_pkuerr(void __user *addr, u32 pkey);
333 int send_sig_perf(void __user *addr, u32 type, u64 sig_data);
334
335 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
336 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
337 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
338 struct task_struct *t);
339 int force_sig_seccomp(int syscall, int reason, bool force_coredump);
340
341 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
342 extern void force_sigsegv(int sig);
343 extern int force_sig_info(struct kernel_siginfo *);
344 extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
345 extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
346 extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
347 const struct cred *);
348 extern int kill_pgrp(struct pid *pid, int sig, int priv);
349 extern int kill_pid(struct pid *pid, int sig, int priv);
350 extern __must_check bool do_notify_parent(struct task_struct *, int);
351 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
352 extern void force_sig(int);
353 extern void force_fatal_sig(int);
354 extern void force_exit_sig(int);
355 extern int send_sig(int, struct task_struct *, int);
356 extern int zap_other_threads(struct task_struct *p);
357 extern struct sigqueue *sigqueue_alloc(void);
358 extern void sigqueue_free(struct sigqueue *);
359 extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
360 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
361
clear_notify_signal(void)362 static inline void clear_notify_signal(void)
363 {
364 clear_thread_flag(TIF_NOTIFY_SIGNAL);
365 smp_mb__after_atomic();
366 }
367
368 /*
369 * Returns 'true' if kick_process() is needed to force a transition from
370 * user -> kernel to guarantee expedient run of TWA_SIGNAL based task_work.
371 */
__set_notify_signal(struct task_struct * task)372 static inline bool __set_notify_signal(struct task_struct *task)
373 {
374 return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) &&
375 !wake_up_state(task, TASK_INTERRUPTIBLE);
376 }
377
378 /*
379 * Called to break out of interruptible wait loops, and enter the
380 * exit_to_user_mode_loop().
381 */
set_notify_signal(struct task_struct * task)382 static inline void set_notify_signal(struct task_struct *task)
383 {
384 if (__set_notify_signal(task))
385 kick_process(task);
386 }
387
restart_syscall(void)388 static inline int restart_syscall(void)
389 {
390 set_tsk_thread_flag(current, TIF_SIGPENDING);
391 return -ERESTARTNOINTR;
392 }
393
task_sigpending(struct task_struct * p)394 static inline int task_sigpending(struct task_struct *p)
395 {
396 return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
397 }
398
signal_pending(struct task_struct * p)399 static inline int signal_pending(struct task_struct *p)
400 {
401 /*
402 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
403 * behavior in terms of ensuring that we break out of wait loops
404 * so that notify signal callbacks can be processed.
405 */
406 if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
407 return 1;
408 return task_sigpending(p);
409 }
410
__fatal_signal_pending(struct task_struct * p)411 static inline int __fatal_signal_pending(struct task_struct *p)
412 {
413 return unlikely(sigismember(&p->pending.signal, SIGKILL));
414 }
415
fatal_signal_pending(struct task_struct * p)416 static inline int fatal_signal_pending(struct task_struct *p)
417 {
418 return task_sigpending(p) && __fatal_signal_pending(p);
419 }
420
signal_pending_state(unsigned int state,struct task_struct * p)421 static inline int signal_pending_state(unsigned int state, struct task_struct *p)
422 {
423 if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
424 return 0;
425 if (!signal_pending(p))
426 return 0;
427
428 return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
429 }
430
431 /*
432 * This should only be used in fault handlers to decide whether we
433 * should stop the current fault routine to handle the signals
434 * instead, especially with the case where we've got interrupted with
435 * a VM_FAULT_RETRY.
436 */
fault_signal_pending(vm_fault_t fault_flags,struct pt_regs * regs)437 static inline bool fault_signal_pending(vm_fault_t fault_flags,
438 struct pt_regs *regs)
439 {
440 return unlikely((fault_flags & VM_FAULT_RETRY) &&
441 (fatal_signal_pending(current) ||
442 (user_mode(regs) && signal_pending(current))));
443 }
444
445 /*
446 * Reevaluate whether the task has signals pending delivery.
447 * Wake the task if so.
448 * This is required every time the blocked sigset_t changes.
449 * callers must hold sighand->siglock.
450 */
451 extern void recalc_sigpending_and_wake(struct task_struct *t);
452 extern void recalc_sigpending(void);
453 extern void calculate_sigpending(void);
454
455 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
456
signal_wake_up(struct task_struct * t,bool fatal)457 static inline void signal_wake_up(struct task_struct *t, bool fatal)
458 {
459 unsigned int state = 0;
460 if (fatal && !(t->jobctl & JOBCTL_PTRACE_FROZEN)) {
461 t->jobctl &= ~(JOBCTL_STOPPED | JOBCTL_TRACED);
462 state = TASK_WAKEKILL | __TASK_TRACED;
463 }
464 signal_wake_up_state(t, state);
465 }
ptrace_signal_wake_up(struct task_struct * t,bool resume)466 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
467 {
468 unsigned int state = 0;
469 if (resume) {
470 t->jobctl &= ~JOBCTL_TRACED;
471 state = __TASK_TRACED;
472 }
473 signal_wake_up_state(t, state);
474 }
475
476 void task_join_group_stop(struct task_struct *task);
477
478 #ifdef TIF_RESTORE_SIGMASK
479 /*
480 * Legacy restore_sigmask accessors. These are inefficient on
481 * SMP architectures because they require atomic operations.
482 */
483
484 /**
485 * set_restore_sigmask() - make sure saved_sigmask processing gets done
486 *
487 * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
488 * will run before returning to user mode, to process the flag. For
489 * all callers, TIF_SIGPENDING is already set or it's no harm to set
490 * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the
491 * arch code will notice on return to user mode, in case those bits
492 * are scarce. We set TIF_SIGPENDING here to ensure that the arch
493 * signal code always gets run when TIF_RESTORE_SIGMASK is set.
494 */
set_restore_sigmask(void)495 static inline void set_restore_sigmask(void)
496 {
497 set_thread_flag(TIF_RESTORE_SIGMASK);
498 }
499
clear_tsk_restore_sigmask(struct task_struct * task)500 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
501 {
502 clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
503 }
504
clear_restore_sigmask(void)505 static inline void clear_restore_sigmask(void)
506 {
507 clear_thread_flag(TIF_RESTORE_SIGMASK);
508 }
test_tsk_restore_sigmask(struct task_struct * task)509 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
510 {
511 return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
512 }
test_restore_sigmask(void)513 static inline bool test_restore_sigmask(void)
514 {
515 return test_thread_flag(TIF_RESTORE_SIGMASK);
516 }
test_and_clear_restore_sigmask(void)517 static inline bool test_and_clear_restore_sigmask(void)
518 {
519 return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
520 }
521
522 #else /* TIF_RESTORE_SIGMASK */
523
524 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
set_restore_sigmask(void)525 static inline void set_restore_sigmask(void)
526 {
527 current->restore_sigmask = true;
528 }
clear_tsk_restore_sigmask(struct task_struct * task)529 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
530 {
531 task->restore_sigmask = false;
532 }
clear_restore_sigmask(void)533 static inline void clear_restore_sigmask(void)
534 {
535 current->restore_sigmask = false;
536 }
test_restore_sigmask(void)537 static inline bool test_restore_sigmask(void)
538 {
539 return current->restore_sigmask;
540 }
test_tsk_restore_sigmask(struct task_struct * task)541 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
542 {
543 return task->restore_sigmask;
544 }
test_and_clear_restore_sigmask(void)545 static inline bool test_and_clear_restore_sigmask(void)
546 {
547 if (!current->restore_sigmask)
548 return false;
549 current->restore_sigmask = false;
550 return true;
551 }
552 #endif
553
restore_saved_sigmask(void)554 static inline void restore_saved_sigmask(void)
555 {
556 if (test_and_clear_restore_sigmask())
557 __set_current_blocked(¤t->saved_sigmask);
558 }
559
560 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
561
restore_saved_sigmask_unless(bool interrupted)562 static inline void restore_saved_sigmask_unless(bool interrupted)
563 {
564 if (interrupted)
565 WARN_ON(!signal_pending(current));
566 else
567 restore_saved_sigmask();
568 }
569
sigmask_to_save(void)570 static inline sigset_t *sigmask_to_save(void)
571 {
572 sigset_t *res = ¤t->blocked;
573 if (unlikely(test_restore_sigmask()))
574 res = ¤t->saved_sigmask;
575 return res;
576 }
577
kill_cad_pid(int sig,int priv)578 static inline int kill_cad_pid(int sig, int priv)
579 {
580 return kill_pid(cad_pid, sig, priv);
581 }
582
583 /* These can be the second arg to send_sig_info/send_group_sig_info. */
584 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
585 #define SEND_SIG_PRIV ((struct kernel_siginfo *) 1)
586
__on_sig_stack(unsigned long sp)587 static inline int __on_sig_stack(unsigned long sp)
588 {
589 #ifdef CONFIG_STACK_GROWSUP
590 return sp >= current->sas_ss_sp &&
591 sp - current->sas_ss_sp < current->sas_ss_size;
592 #else
593 return sp > current->sas_ss_sp &&
594 sp - current->sas_ss_sp <= current->sas_ss_size;
595 #endif
596 }
597
598 /*
599 * True if we are on the alternate signal stack.
600 */
on_sig_stack(unsigned long sp)601 static inline int on_sig_stack(unsigned long sp)
602 {
603 /*
604 * If the signal stack is SS_AUTODISARM then, by construction, we
605 * can't be on the signal stack unless user code deliberately set
606 * SS_AUTODISARM when we were already on it.
607 *
608 * This improves reliability: if user state gets corrupted such that
609 * the stack pointer points very close to the end of the signal stack,
610 * then this check will enable the signal to be handled anyway.
611 */
612 if (current->sas_ss_flags & SS_AUTODISARM)
613 return 0;
614
615 return __on_sig_stack(sp);
616 }
617
sas_ss_flags(unsigned long sp)618 static inline int sas_ss_flags(unsigned long sp)
619 {
620 if (!current->sas_ss_size)
621 return SS_DISABLE;
622
623 return on_sig_stack(sp) ? SS_ONSTACK : 0;
624 }
625
sas_ss_reset(struct task_struct * p)626 static inline void sas_ss_reset(struct task_struct *p)
627 {
628 p->sas_ss_sp = 0;
629 p->sas_ss_size = 0;
630 p->sas_ss_flags = SS_DISABLE;
631 }
632
sigsp(unsigned long sp,struct ksignal * ksig)633 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
634 {
635 if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
636 #ifdef CONFIG_STACK_GROWSUP
637 return current->sas_ss_sp;
638 #else
639 return current->sas_ss_sp + current->sas_ss_size;
640 #endif
641 return sp;
642 }
643
644 extern void __cleanup_sighand(struct sighand_struct *);
645 extern void flush_itimer_signals(void);
646
647 #define tasklist_empty() \
648 list_empty(&init_task.tasks)
649
650 #define next_task(p) \
651 list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
652
653 #define for_each_process(p) \
654 for (p = &init_task ; (p = next_task(p)) != &init_task ; )
655
656 extern bool current_is_single_threaded(void);
657
658 /*
659 * Without tasklist/siglock it is only rcu-safe if g can't exit/exec,
660 * otherwise next_thread(t) will never reach g after list_del_rcu(g).
661 */
662 #define while_each_thread(g, t) \
663 while ((t = next_thread(t)) != g)
664
665 #define __for_each_thread(signal, t) \
666 list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)
667
668 #define for_each_thread(p, t) \
669 __for_each_thread((p)->signal, t)
670
671 /* Careful: this is a double loop, 'break' won't work as expected. */
672 #define for_each_process_thread(p, t) \
673 for_each_process(p) for_each_thread(p, t)
674
675 typedef int (*proc_visitor)(struct task_struct *p, void *data);
676 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
677
678 static inline
task_pid_type(struct task_struct * task,enum pid_type type)679 struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
680 {
681 struct pid *pid;
682 if (type == PIDTYPE_PID)
683 pid = task_pid(task);
684 else
685 pid = task->signal->pids[type];
686 return pid;
687 }
688
task_tgid(struct task_struct * task)689 static inline struct pid *task_tgid(struct task_struct *task)
690 {
691 return task->signal->pids[PIDTYPE_TGID];
692 }
693
694 /*
695 * Without tasklist or RCU lock it is not safe to dereference
696 * the result of task_pgrp/task_session even if task == current,
697 * we can race with another thread doing sys_setsid/sys_setpgid.
698 */
task_pgrp(struct task_struct * task)699 static inline struct pid *task_pgrp(struct task_struct *task)
700 {
701 return task->signal->pids[PIDTYPE_PGID];
702 }
703
task_session(struct task_struct * task)704 static inline struct pid *task_session(struct task_struct *task)
705 {
706 return task->signal->pids[PIDTYPE_SID];
707 }
708
get_nr_threads(struct task_struct * task)709 static inline int get_nr_threads(struct task_struct *task)
710 {
711 return task->signal->nr_threads;
712 }
713
thread_group_leader(struct task_struct * p)714 static inline bool thread_group_leader(struct task_struct *p)
715 {
716 return p->exit_signal >= 0;
717 }
718
719 static inline
same_thread_group(struct task_struct * p1,struct task_struct * p2)720 bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
721 {
722 return p1->signal == p2->signal;
723 }
724
next_thread(const struct task_struct * p)725 static inline struct task_struct *next_thread(const struct task_struct *p)
726 {
727 return list_entry_rcu(p->thread_group.next,
728 struct task_struct, thread_group);
729 }
730
thread_group_empty(struct task_struct * p)731 static inline int thread_group_empty(struct task_struct *p)
732 {
733 return list_empty(&p->thread_group);
734 }
735
736 #define delay_group_leader(p) \
737 (thread_group_leader(p) && !thread_group_empty(p))
738
739 extern bool thread_group_exited(struct pid *pid);
740
741 extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
742 unsigned long *flags);
743
lock_task_sighand(struct task_struct * task,unsigned long * flags)744 static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
745 unsigned long *flags)
746 {
747 struct sighand_struct *ret;
748
749 ret = __lock_task_sighand(task, flags);
750 (void)__cond_lock(&task->sighand->siglock, ret);
751 return ret;
752 }
753
unlock_task_sighand(struct task_struct * task,unsigned long * flags)754 static inline void unlock_task_sighand(struct task_struct *task,
755 unsigned long *flags)
756 {
757 spin_unlock_irqrestore(&task->sighand->siglock, *flags);
758 }
759
760 #ifdef CONFIG_LOCKDEP
761 extern void lockdep_assert_task_sighand_held(struct task_struct *task);
762 #else
lockdep_assert_task_sighand_held(struct task_struct * task)763 static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { }
764 #endif
765
task_rlimit(const struct task_struct * task,unsigned int limit)766 static inline unsigned long task_rlimit(const struct task_struct *task,
767 unsigned int limit)
768 {
769 return READ_ONCE(task->signal->rlim[limit].rlim_cur);
770 }
771
task_rlimit_max(const struct task_struct * task,unsigned int limit)772 static inline unsigned long task_rlimit_max(const struct task_struct *task,
773 unsigned int limit)
774 {
775 return READ_ONCE(task->signal->rlim[limit].rlim_max);
776 }
777
rlimit(unsigned int limit)778 static inline unsigned long rlimit(unsigned int limit)
779 {
780 return task_rlimit(current, limit);
781 }
782
rlimit_max(unsigned int limit)783 static inline unsigned long rlimit_max(unsigned int limit)
784 {
785 return task_rlimit_max(current, limit);
786 }
787
788 #endif /* _LINUX_SCHED_SIGNAL_H */
789