1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SCHED_SIGNAL_H
3 #define _LINUX_SCHED_SIGNAL_H
4
5 #include <linux/rculist.h>
6 #include <linux/signal.h>
7 #include <linux/sched.h>
8 #include <linux/sched/jobctl.h>
9 #include <linux/sched/task.h>
10 #include <linux/cred.h>
11 #include <linux/refcount.h>
12 #include <linux/posix-timers.h>
13 #include <linux/mm_types.h>
14 #include <asm/ptrace.h>
15
16 /*
17 * Types defining task->signal and task->sighand and APIs using them:
18 */
19
20 struct sighand_struct {
21 spinlock_t siglock;
22 refcount_t count;
23 wait_queue_head_t signalfd_wqh;
24 struct k_sigaction action[_NSIG];
25 };
26
27 /*
28 * Per-process accounting stats:
29 */
30 struct pacct_struct {
31 int ac_flag;
32 long ac_exitcode;
33 unsigned long ac_mem;
34 u64 ac_utime, ac_stime;
35 unsigned long ac_minflt, ac_majflt;
36 };
37
38 struct cpu_itimer {
39 u64 expires;
40 u64 incr;
41 };
42
43 /*
44 * This is the atomic variant of task_cputime, which can be used for
45 * storing and updating task_cputime statistics without locking.
46 */
47 struct task_cputime_atomic {
48 atomic64_t utime;
49 atomic64_t stime;
50 atomic64_t sum_exec_runtime;
51 };
52
53 #define INIT_CPUTIME_ATOMIC \
54 (struct task_cputime_atomic) { \
55 .utime = ATOMIC64_INIT(0), \
56 .stime = ATOMIC64_INIT(0), \
57 .sum_exec_runtime = ATOMIC64_INIT(0), \
58 }
59 /**
60 * struct thread_group_cputimer - thread group interval timer counts
61 * @cputime_atomic: atomic thread group interval timers.
62 *
63 * This structure contains the version of task_cputime, above, that is
64 * used for thread group CPU timer calculations.
65 */
66 struct thread_group_cputimer {
67 struct task_cputime_atomic cputime_atomic;
68 };
69
70 struct multiprocess_signals {
71 sigset_t signal;
72 struct hlist_node node;
73 };
74
75 struct core_thread {
76 struct task_struct *task;
77 struct core_thread *next;
78 };
79
80 struct core_state {
81 atomic_t nr_threads;
82 struct core_thread dumper;
83 struct completion startup;
84 };
85
86 /*
87 * NOTE! "signal_struct" does not have its own
88 * locking, because a shared signal_struct always
89 * implies a shared sighand_struct, so locking
90 * sighand_struct is always a proper superset of
91 * the locking of signal_struct.
92 */
93 struct signal_struct {
94 refcount_t sigcnt;
95 atomic_t live;
96 int nr_threads;
97 int quick_threads;
98 struct list_head thread_head;
99
100 wait_queue_head_t wait_chldexit; /* for wait4() */
101
102 /* current thread group signal load-balancing target: */
103 struct task_struct *curr_target;
104
105 /* shared signal handling: */
106 struct sigpending shared_pending;
107
108 /* For collecting multiprocess signals during fork */
109 struct hlist_head multiprocess;
110
111 /* thread group exit support */
112 int group_exit_code;
113 /* notify group_exec_task when notify_count is less or equal to 0 */
114 int notify_count;
115 struct task_struct *group_exec_task;
116
117 /* thread group stop support, overloads group_exit_code too */
118 int group_stop_count;
119 unsigned int flags; /* see SIGNAL_* flags below */
120
121 struct core_state *core_state; /* coredumping support */
122
123 /*
124 * PR_SET_CHILD_SUBREAPER marks a process, like a service
125 * manager, to re-parent orphan (double-forking) child processes
126 * to this process instead of 'init'. The service manager is
127 * able to receive SIGCHLD signals and is able to investigate
128 * the process until it calls wait(). All children of this
129 * process will inherit a flag if they should look for a
130 * child_subreaper process at exit.
131 */
132 unsigned int is_child_subreaper:1;
133 unsigned int has_child_subreaper:1;
134
135 #ifdef CONFIG_POSIX_TIMERS
136
137 /* POSIX.1b Interval Timers */
138 unsigned int next_posix_timer_id;
139 struct list_head posix_timers;
140
141 /* ITIMER_REAL timer for the process */
142 struct hrtimer real_timer;
143 ktime_t it_real_incr;
144
145 /*
146 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
147 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
148 * values are defined to 0 and 1 respectively
149 */
150 struct cpu_itimer it[2];
151
152 /*
153 * Thread group totals for process CPU timers.
154 * See thread_group_cputimer(), et al, for details.
155 */
156 struct thread_group_cputimer cputimer;
157
158 #endif
159 /* Empty if CONFIG_POSIX_TIMERS=n */
160 struct posix_cputimers posix_cputimers;
161
162 /* PID/PID hash table linkage. */
163 struct pid *pids[PIDTYPE_MAX];
164
165 #ifdef CONFIG_NO_HZ_FULL
166 atomic_t tick_dep_mask;
167 #endif
168
169 struct pid *tty_old_pgrp;
170
171 /* boolean value for session group leader */
172 int leader;
173
174 struct tty_struct *tty; /* NULL if no tty */
175
176 #ifdef CONFIG_SCHED_AUTOGROUP
177 struct autogroup *autogroup;
178 #endif
179 /*
180 * Cumulative resource counters for dead threads in the group,
181 * and for reaped dead child processes forked by this group.
182 * Live threads maintain their own counters and add to these
183 * in __exit_signal, except for the group leader.
184 */
185 seqlock_t stats_lock;
186 u64 utime, stime, cutime, cstime;
187 u64 gtime;
188 u64 cgtime;
189 struct prev_cputime prev_cputime;
190 unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
191 unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
192 unsigned long inblock, oublock, cinblock, coublock;
193 unsigned long maxrss, cmaxrss;
194 struct task_io_accounting ioac;
195
196 /*
197 * Cumulative ns of schedule CPU time fo dead threads in the
198 * group, not including a zombie group leader, (This only differs
199 * from jiffies_to_ns(utime + stime) if sched_clock uses something
200 * other than jiffies.)
201 */
202 unsigned long long sum_sched_runtime;
203
204 /*
205 * We don't bother to synchronize most readers of this at all,
206 * because there is no reader checking a limit that actually needs
207 * to get both rlim_cur and rlim_max atomically, and either one
208 * alone is a single word that can safely be read normally.
209 * getrlimit/setrlimit use task_lock(current->group_leader) to
210 * protect this instead of the siglock, because they really
211 * have no need to disable irqs.
212 */
213 struct rlimit rlim[RLIM_NLIMITS];
214
215 #ifdef CONFIG_BSD_PROCESS_ACCT
216 struct pacct_struct pacct; /* per-process accounting information */
217 #endif
218 #ifdef CONFIG_TASKSTATS
219 struct taskstats *stats;
220 #endif
221 #ifdef CONFIG_AUDIT
222 unsigned audit_tty;
223 struct tty_audit_buf *tty_audit_buf;
224 #endif
225
226 /*
227 * Thread is the potential origin of an oom condition; kill first on
228 * oom
229 */
230 bool oom_flag_origin;
231 short oom_score_adj; /* OOM kill score adjustment */
232 short oom_score_adj_min; /* OOM kill score adjustment min value.
233 * Only settable by CAP_SYS_RESOURCE. */
234 struct mm_struct *oom_mm; /* recorded mm when the thread group got
235 * killed by the oom killer */
236
237 struct mutex cred_guard_mutex; /* guard against foreign influences on
238 * credential calculations
239 * (notably. ptrace)
240 * Deprecated do not use in new code.
241 * Use exec_update_lock instead.
242 */
243 struct rw_semaphore exec_update_lock; /* Held while task_struct is
244 * being updated during exec,
245 * and may have inconsistent
246 * permissions.
247 */
248 } __randomize_layout;
249
250 /*
251 * Bits in flags field of signal_struct.
252 */
253 #define SIGNAL_STOP_STOPPED 0x00000001 /* job control stop in effect */
254 #define SIGNAL_STOP_CONTINUED 0x00000002 /* SIGCONT since WCONTINUED reap */
255 #define SIGNAL_GROUP_EXIT 0x00000004 /* group exit in progress */
256 /*
257 * Pending notifications to parent.
258 */
259 #define SIGNAL_CLD_STOPPED 0x00000010
260 #define SIGNAL_CLD_CONTINUED 0x00000020
261 #define SIGNAL_CLD_MASK (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
262
263 #define SIGNAL_UNKILLABLE 0x00000040 /* for init: ignore fatal signals */
264
265 #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
266 SIGNAL_STOP_CONTINUED)
267
signal_set_stop_flags(struct signal_struct * sig,unsigned int flags)268 static inline void signal_set_stop_flags(struct signal_struct *sig,
269 unsigned int flags)
270 {
271 WARN_ON(sig->flags & SIGNAL_GROUP_EXIT);
272 sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
273 }
274
275 extern void flush_signals(struct task_struct *);
276 extern void ignore_signals(struct task_struct *);
277 extern void flush_signal_handlers(struct task_struct *, int force_default);
278 extern int dequeue_signal(struct task_struct *task, sigset_t *mask,
279 kernel_siginfo_t *info, enum pid_type *type);
280
kernel_dequeue_signal(void)281 static inline int kernel_dequeue_signal(void)
282 {
283 struct task_struct *task = current;
284 kernel_siginfo_t __info;
285 enum pid_type __type;
286 int ret;
287
288 spin_lock_irq(&task->sighand->siglock);
289 ret = dequeue_signal(task, &task->blocked, &__info, &__type);
290 spin_unlock_irq(&task->sighand->siglock);
291
292 return ret;
293 }
294
kernel_signal_stop(void)295 static inline void kernel_signal_stop(void)
296 {
297 spin_lock_irq(¤t->sighand->siglock);
298 if (current->jobctl & JOBCTL_STOP_DEQUEUED) {
299 current->jobctl |= JOBCTL_STOPPED;
300 set_special_state(TASK_STOPPED);
301 }
302 spin_unlock_irq(¤t->sighand->siglock);
303
304 schedule();
305 }
306 #ifdef __ia64__
307 # define ___ARCH_SI_IA64(_a1, _a2, _a3) , _a1, _a2, _a3
308 #else
309 # define ___ARCH_SI_IA64(_a1, _a2, _a3)
310 #endif
311
312 int force_sig_fault_to_task(int sig, int code, void __user *addr
313 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
314 , struct task_struct *t);
315 int force_sig_fault(int sig, int code, void __user *addr
316 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr));
317 int send_sig_fault(int sig, int code, void __user *addr
318 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
319 , struct task_struct *t);
320
321 int force_sig_mceerr(int code, void __user *, short);
322 int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
323
324 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
325 int force_sig_pkuerr(void __user *addr, u32 pkey);
326 int send_sig_perf(void __user *addr, u32 type, u64 sig_data);
327
328 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
329 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
330 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
331 struct task_struct *t);
332 int force_sig_seccomp(int syscall, int reason, bool force_coredump);
333
334 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
335 extern void force_sigsegv(int sig);
336 extern int force_sig_info(struct kernel_siginfo *);
337 extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
338 extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
339 extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
340 const struct cred *);
341 extern int kill_pgrp(struct pid *pid, int sig, int priv);
342 extern int kill_pid(struct pid *pid, int sig, int priv);
343 extern __must_check bool do_notify_parent(struct task_struct *, int);
344 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
345 extern void force_sig(int);
346 extern void force_fatal_sig(int);
347 extern void force_exit_sig(int);
348 extern int send_sig(int, struct task_struct *, int);
349 extern int zap_other_threads(struct task_struct *p);
350 extern struct sigqueue *sigqueue_alloc(void);
351 extern void sigqueue_free(struct sigqueue *);
352 extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
353 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
354
clear_notify_signal(void)355 static inline void clear_notify_signal(void)
356 {
357 clear_thread_flag(TIF_NOTIFY_SIGNAL);
358 smp_mb__after_atomic();
359 }
360
361 /*
362 * Returns 'true' if kick_process() is needed to force a transition from
363 * user -> kernel to guarantee expedient run of TWA_SIGNAL based task_work.
364 */
__set_notify_signal(struct task_struct * task)365 static inline bool __set_notify_signal(struct task_struct *task)
366 {
367 return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) &&
368 !wake_up_state(task, TASK_INTERRUPTIBLE);
369 }
370
371 /*
372 * Called to break out of interruptible wait loops, and enter the
373 * exit_to_user_mode_loop().
374 */
set_notify_signal(struct task_struct * task)375 static inline void set_notify_signal(struct task_struct *task)
376 {
377 if (__set_notify_signal(task))
378 kick_process(task);
379 }
380
restart_syscall(void)381 static inline int restart_syscall(void)
382 {
383 set_tsk_thread_flag(current, TIF_SIGPENDING);
384 return -ERESTARTNOINTR;
385 }
386
task_sigpending(struct task_struct * p)387 static inline int task_sigpending(struct task_struct *p)
388 {
389 return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
390 }
391
signal_pending(struct task_struct * p)392 static inline int signal_pending(struct task_struct *p)
393 {
394 /*
395 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
396 * behavior in terms of ensuring that we break out of wait loops
397 * so that notify signal callbacks can be processed.
398 */
399 if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
400 return 1;
401 return task_sigpending(p);
402 }
403
__fatal_signal_pending(struct task_struct * p)404 static inline int __fatal_signal_pending(struct task_struct *p)
405 {
406 return unlikely(sigismember(&p->pending.signal, SIGKILL));
407 }
408
fatal_signal_pending(struct task_struct * p)409 static inline int fatal_signal_pending(struct task_struct *p)
410 {
411 return task_sigpending(p) && __fatal_signal_pending(p);
412 }
413
signal_pending_state(unsigned int state,struct task_struct * p)414 static inline int signal_pending_state(unsigned int state, struct task_struct *p)
415 {
416 if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
417 return 0;
418 if (!signal_pending(p))
419 return 0;
420
421 return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
422 }
423
424 /*
425 * This should only be used in fault handlers to decide whether we
426 * should stop the current fault routine to handle the signals
427 * instead, especially with the case where we've got interrupted with
428 * a VM_FAULT_RETRY.
429 */
fault_signal_pending(vm_fault_t fault_flags,struct pt_regs * regs)430 static inline bool fault_signal_pending(vm_fault_t fault_flags,
431 struct pt_regs *regs)
432 {
433 return unlikely((fault_flags & VM_FAULT_RETRY) &&
434 (fatal_signal_pending(current) ||
435 (user_mode(regs) && signal_pending(current))));
436 }
437
438 /*
439 * Reevaluate whether the task has signals pending delivery.
440 * Wake the task if so.
441 * This is required every time the blocked sigset_t changes.
442 * callers must hold sighand->siglock.
443 */
444 extern void recalc_sigpending_and_wake(struct task_struct *t);
445 extern void recalc_sigpending(void);
446 extern void calculate_sigpending(void);
447
448 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
449
signal_wake_up(struct task_struct * t,bool fatal)450 static inline void signal_wake_up(struct task_struct *t, bool fatal)
451 {
452 unsigned int state = 0;
453 if (fatal && !(t->jobctl & JOBCTL_PTRACE_FROZEN)) {
454 t->jobctl &= ~(JOBCTL_STOPPED | JOBCTL_TRACED);
455 state = TASK_WAKEKILL | __TASK_TRACED;
456 }
457 signal_wake_up_state(t, state);
458 }
ptrace_signal_wake_up(struct task_struct * t,bool resume)459 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
460 {
461 unsigned int state = 0;
462 if (resume) {
463 t->jobctl &= ~JOBCTL_TRACED;
464 state = __TASK_TRACED;
465 }
466 signal_wake_up_state(t, state);
467 }
468
469 void task_join_group_stop(struct task_struct *task);
470
471 #ifdef TIF_RESTORE_SIGMASK
472 /*
473 * Legacy restore_sigmask accessors. These are inefficient on
474 * SMP architectures because they require atomic operations.
475 */
476
477 /**
478 * set_restore_sigmask() - make sure saved_sigmask processing gets done
479 *
480 * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
481 * will run before returning to user mode, to process the flag. For
482 * all callers, TIF_SIGPENDING is already set or it's no harm to set
483 * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the
484 * arch code will notice on return to user mode, in case those bits
485 * are scarce. We set TIF_SIGPENDING here to ensure that the arch
486 * signal code always gets run when TIF_RESTORE_SIGMASK is set.
487 */
set_restore_sigmask(void)488 static inline void set_restore_sigmask(void)
489 {
490 set_thread_flag(TIF_RESTORE_SIGMASK);
491 }
492
clear_tsk_restore_sigmask(struct task_struct * task)493 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
494 {
495 clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
496 }
497
clear_restore_sigmask(void)498 static inline void clear_restore_sigmask(void)
499 {
500 clear_thread_flag(TIF_RESTORE_SIGMASK);
501 }
test_tsk_restore_sigmask(struct task_struct * task)502 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
503 {
504 return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
505 }
test_restore_sigmask(void)506 static inline bool test_restore_sigmask(void)
507 {
508 return test_thread_flag(TIF_RESTORE_SIGMASK);
509 }
test_and_clear_restore_sigmask(void)510 static inline bool test_and_clear_restore_sigmask(void)
511 {
512 return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
513 }
514
515 #else /* TIF_RESTORE_SIGMASK */
516
517 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
set_restore_sigmask(void)518 static inline void set_restore_sigmask(void)
519 {
520 current->restore_sigmask = true;
521 }
clear_tsk_restore_sigmask(struct task_struct * task)522 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
523 {
524 task->restore_sigmask = false;
525 }
clear_restore_sigmask(void)526 static inline void clear_restore_sigmask(void)
527 {
528 current->restore_sigmask = false;
529 }
test_restore_sigmask(void)530 static inline bool test_restore_sigmask(void)
531 {
532 return current->restore_sigmask;
533 }
test_tsk_restore_sigmask(struct task_struct * task)534 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
535 {
536 return task->restore_sigmask;
537 }
test_and_clear_restore_sigmask(void)538 static inline bool test_and_clear_restore_sigmask(void)
539 {
540 if (!current->restore_sigmask)
541 return false;
542 current->restore_sigmask = false;
543 return true;
544 }
545 #endif
546
restore_saved_sigmask(void)547 static inline void restore_saved_sigmask(void)
548 {
549 if (test_and_clear_restore_sigmask())
550 __set_current_blocked(¤t->saved_sigmask);
551 }
552
553 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
554
restore_saved_sigmask_unless(bool interrupted)555 static inline void restore_saved_sigmask_unless(bool interrupted)
556 {
557 if (interrupted)
558 WARN_ON(!signal_pending(current));
559 else
560 restore_saved_sigmask();
561 }
562
sigmask_to_save(void)563 static inline sigset_t *sigmask_to_save(void)
564 {
565 sigset_t *res = ¤t->blocked;
566 if (unlikely(test_restore_sigmask()))
567 res = ¤t->saved_sigmask;
568 return res;
569 }
570
kill_cad_pid(int sig,int priv)571 static inline int kill_cad_pid(int sig, int priv)
572 {
573 return kill_pid(cad_pid, sig, priv);
574 }
575
576 /* These can be the second arg to send_sig_info/send_group_sig_info. */
577 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
578 #define SEND_SIG_PRIV ((struct kernel_siginfo *) 1)
579
__on_sig_stack(unsigned long sp)580 static inline int __on_sig_stack(unsigned long sp)
581 {
582 #ifdef CONFIG_STACK_GROWSUP
583 return sp >= current->sas_ss_sp &&
584 sp - current->sas_ss_sp < current->sas_ss_size;
585 #else
586 return sp > current->sas_ss_sp &&
587 sp - current->sas_ss_sp <= current->sas_ss_size;
588 #endif
589 }
590
591 /*
592 * True if we are on the alternate signal stack.
593 */
on_sig_stack(unsigned long sp)594 static inline int on_sig_stack(unsigned long sp)
595 {
596 /*
597 * If the signal stack is SS_AUTODISARM then, by construction, we
598 * can't be on the signal stack unless user code deliberately set
599 * SS_AUTODISARM when we were already on it.
600 *
601 * This improves reliability: if user state gets corrupted such that
602 * the stack pointer points very close to the end of the signal stack,
603 * then this check will enable the signal to be handled anyway.
604 */
605 if (current->sas_ss_flags & SS_AUTODISARM)
606 return 0;
607
608 return __on_sig_stack(sp);
609 }
610
sas_ss_flags(unsigned long sp)611 static inline int sas_ss_flags(unsigned long sp)
612 {
613 if (!current->sas_ss_size)
614 return SS_DISABLE;
615
616 return on_sig_stack(sp) ? SS_ONSTACK : 0;
617 }
618
sas_ss_reset(struct task_struct * p)619 static inline void sas_ss_reset(struct task_struct *p)
620 {
621 p->sas_ss_sp = 0;
622 p->sas_ss_size = 0;
623 p->sas_ss_flags = SS_DISABLE;
624 }
625
sigsp(unsigned long sp,struct ksignal * ksig)626 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
627 {
628 if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
629 #ifdef CONFIG_STACK_GROWSUP
630 return current->sas_ss_sp;
631 #else
632 return current->sas_ss_sp + current->sas_ss_size;
633 #endif
634 return sp;
635 }
636
637 extern void __cleanup_sighand(struct sighand_struct *);
638 extern void flush_itimer_signals(void);
639
640 #define tasklist_empty() \
641 list_empty(&init_task.tasks)
642
643 #define next_task(p) \
644 list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
645
646 #define for_each_process(p) \
647 for (p = &init_task ; (p = next_task(p)) != &init_task ; )
648
649 extern bool current_is_single_threaded(void);
650
651 /*
652 * Without tasklist/siglock it is only rcu-safe if g can't exit/exec,
653 * otherwise next_thread(t) will never reach g after list_del_rcu(g).
654 */
655 #define while_each_thread(g, t) \
656 while ((t = next_thread(t)) != g)
657
658 #define __for_each_thread(signal, t) \
659 list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)
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
next_thread(const struct task_struct * p)718 static inline struct task_struct *next_thread(const struct task_struct *p)
719 {
720 return list_entry_rcu(p->thread_group.next,
721 struct task_struct, thread_group);
722 }
723
thread_group_empty(struct task_struct * p)724 static inline int thread_group_empty(struct task_struct *p)
725 {
726 return list_empty(&p->thread_group);
727 }
728
729 #define delay_group_leader(p) \
730 (thread_group_leader(p) && !thread_group_empty(p))
731
732 extern bool thread_group_exited(struct pid *pid);
733
734 extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
735 unsigned long *flags);
736
lock_task_sighand(struct task_struct * task,unsigned long * flags)737 static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
738 unsigned long *flags)
739 {
740 struct sighand_struct *ret;
741
742 ret = __lock_task_sighand(task, flags);
743 (void)__cond_lock(&task->sighand->siglock, ret);
744 return ret;
745 }
746
unlock_task_sighand(struct task_struct * task,unsigned long * flags)747 static inline void unlock_task_sighand(struct task_struct *task,
748 unsigned long *flags)
749 {
750 spin_unlock_irqrestore(&task->sighand->siglock, *flags);
751 }
752
753 #ifdef CONFIG_LOCKDEP
754 extern void lockdep_assert_task_sighand_held(struct task_struct *task);
755 #else
lockdep_assert_task_sighand_held(struct task_struct * task)756 static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { }
757 #endif
758
task_rlimit(const struct task_struct * task,unsigned int limit)759 static inline unsigned long task_rlimit(const struct task_struct *task,
760 unsigned int limit)
761 {
762 return READ_ONCE(task->signal->rlim[limit].rlim_cur);
763 }
764
task_rlimit_max(const struct task_struct * task,unsigned int limit)765 static inline unsigned long task_rlimit_max(const struct task_struct *task,
766 unsigned int limit)
767 {
768 return READ_ONCE(task->signal->rlim[limit].rlim_max);
769 }
770
rlimit(unsigned int limit)771 static inline unsigned long rlimit(unsigned int limit)
772 {
773 return task_rlimit(current, limit);
774 }
775
rlimit_max(unsigned int limit)776 static inline unsigned long rlimit_max(unsigned int limit)
777 {
778 return task_rlimit_max(current, limit);
779 }
780
781 #endif /* _LINUX_SCHED_SIGNAL_H */
782