1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SCHED_SIGNAL_H
3 #define _LINUX_SCHED_SIGNAL_H
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>
17 * Types defining task->signal and task->sighand and APIs using them:
20 struct sighand_struct {
23 wait_queue_head_t signalfd_wqh;
24 struct k_sigaction action[_NSIG];
28 * Per-process accounting stats:
34 u64 ac_utime, ac_stime;
35 unsigned long ac_minflt, ac_majflt;
44 * This is the atomic variant of task_cputime, which can be used for
45 * storing and updating task_cputime statistics without locking.
47 struct task_cputime_atomic {
50 atomic64_t sum_exec_runtime;
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), \
60 * struct thread_group_cputimer - thread group interval timer counts
61 * @cputime_atomic: atomic thread group interval timers.
63 * This structure contains the version of task_cputime, above, that is
64 * used for thread group CPU timer calculations.
66 struct thread_group_cputimer {
67 struct task_cputime_atomic cputime_atomic;
70 struct multiprocess_signals {
72 struct hlist_node node;
76 struct task_struct *task;
77 struct core_thread *next;
82 struct core_thread dumper;
83 struct completion startup;
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.
93 struct signal_struct {
97 struct list_head thread_head;
99 wait_queue_head_t wait_chldexit; /* for wait4() */
101 /* current thread group signal load-balancing target: */
102 struct task_struct *curr_target;
104 /* shared signal handling: */
105 struct sigpending shared_pending;
107 /* For collecting multiprocess signals during fork */
108 struct hlist_head multiprocess;
110 /* thread group exit support */
112 /* notify group_exec_task when notify_count is less or equal to 0 */
114 struct task_struct *group_exec_task;
116 /* thread group stop support, overloads group_exit_code too */
117 int group_stop_count;
118 unsigned int flags; /* see SIGNAL_* flags below */
120 struct core_state *core_state; /* coredumping support */
123 * PR_SET_CHILD_SUBREAPER marks a process, like a service
124 * manager, to re-parent orphan (double-forking) child processes
125 * to this process instead of 'init'. The service manager is
126 * able to receive SIGCHLD signals and is able to investigate
127 * the process until it calls wait(). All children of this
128 * process will inherit a flag if they should look for a
129 * child_subreaper process at exit.
131 unsigned int is_child_subreaper:1;
132 unsigned int has_child_subreaper:1;
134 #ifdef CONFIG_POSIX_TIMERS
136 /* POSIX.1b Interval Timers */
138 struct list_head posix_timers;
140 /* ITIMER_REAL timer for the process */
141 struct hrtimer real_timer;
142 ktime_t it_real_incr;
145 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
146 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
147 * values are defined to 0 and 1 respectively
149 struct cpu_itimer it[2];
152 * Thread group totals for process CPU timers.
153 * See thread_group_cputimer(), et al, for details.
155 struct thread_group_cputimer cputimer;
158 /* Empty if CONFIG_POSIX_TIMERS=n */
159 struct posix_cputimers posix_cputimers;
161 /* PID/PID hash table linkage. */
162 struct pid *pids[PIDTYPE_MAX];
164 #ifdef CONFIG_NO_HZ_FULL
165 atomic_t tick_dep_mask;
168 struct pid *tty_old_pgrp;
170 /* boolean value for session group leader */
173 struct tty_struct *tty; /* NULL if no tty */
175 #ifdef CONFIG_SCHED_AUTOGROUP
176 struct autogroup *autogroup;
179 * Cumulative resource counters for dead threads in the group,
180 * and for reaped dead child processes forked by this group.
181 * Live threads maintain their own counters and add to these
182 * in __exit_signal, except for the group leader.
184 seqlock_t stats_lock;
185 u64 utime, stime, cutime, cstime;
188 struct prev_cputime prev_cputime;
189 unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
190 unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
191 unsigned long inblock, oublock, cinblock, coublock;
192 unsigned long maxrss, cmaxrss;
193 struct task_io_accounting ioac;
196 * Cumulative ns of schedule CPU time fo dead threads in the
197 * group, not including a zombie group leader, (This only differs
198 * from jiffies_to_ns(utime + stime) if sched_clock uses something
199 * other than jiffies.)
201 unsigned long long sum_sched_runtime;
204 * We don't bother to synchronize most readers of this at all,
205 * because there is no reader checking a limit that actually needs
206 * to get both rlim_cur and rlim_max atomically, and either one
207 * alone is a single word that can safely be read normally.
208 * getrlimit/setrlimit use task_lock(current->group_leader) to
209 * protect this instead of the siglock, because they really
210 * have no need to disable irqs.
212 struct rlimit rlim[RLIM_NLIMITS];
214 #ifdef CONFIG_BSD_PROCESS_ACCT
215 struct pacct_struct pacct; /* per-process accounting information */
217 #ifdef CONFIG_TASKSTATS
218 struct taskstats *stats;
222 struct tty_audit_buf *tty_audit_buf;
226 * Thread is the potential origin of an oom condition; kill first on
229 bool oom_flag_origin;
230 short oom_score_adj; /* OOM kill score adjustment */
231 short oom_score_adj_min; /* OOM kill score adjustment min value.
232 * Only settable by CAP_SYS_RESOURCE. */
233 struct mm_struct *oom_mm; /* recorded mm when the thread group got
234 * killed by the oom killer */
236 struct mutex cred_guard_mutex; /* guard against foreign influences on
237 * credential calculations
239 * Deprecated do not use in new code.
240 * Use exec_update_lock instead.
242 struct rw_semaphore exec_update_lock; /* Held while task_struct is
243 * being updated during exec,
244 * and may have inconsistent
247 } __randomize_layout;
250 * Bits in flags field of signal_struct.
252 #define SIGNAL_STOP_STOPPED 0x00000001 /* job control stop in effect */
253 #define SIGNAL_STOP_CONTINUED 0x00000002 /* SIGCONT since WCONTINUED reap */
254 #define SIGNAL_GROUP_EXIT 0x00000004 /* group exit in progress */
256 * Pending notifications to parent.
258 #define SIGNAL_CLD_STOPPED 0x00000010
259 #define SIGNAL_CLD_CONTINUED 0x00000020
260 #define SIGNAL_CLD_MASK (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
262 #define SIGNAL_UNKILLABLE 0x00000040 /* for init: ignore fatal signals */
264 #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
265 SIGNAL_STOP_CONTINUED)
267 static inline void signal_set_stop_flags(struct signal_struct *sig,
270 WARN_ON(sig->flags & SIGNAL_GROUP_EXIT);
271 sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
274 extern void flush_signals(struct task_struct *);
275 extern void ignore_signals(struct task_struct *);
276 extern void flush_signal_handlers(struct task_struct *, int force_default);
277 extern int dequeue_signal(struct task_struct *task, sigset_t *mask,
278 kernel_siginfo_t *info, enum pid_type *type);
280 static inline int kernel_dequeue_signal(void)
282 struct task_struct *task = current;
283 kernel_siginfo_t __info;
284 enum pid_type __type;
287 spin_lock_irq(&task->sighand->siglock);
288 ret = dequeue_signal(task, &task->blocked, &__info, &__type);
289 spin_unlock_irq(&task->sighand->siglock);
294 static inline void kernel_signal_stop(void)
296 spin_lock_irq(¤t->sighand->siglock);
297 if (current->jobctl & JOBCTL_STOP_DEQUEUED) {
298 current->jobctl |= JOBCTL_STOPPED;
299 set_special_state(TASK_STOPPED);
301 spin_unlock_irq(¤t->sighand->siglock);
306 # define ___ARCH_SI_IA64(_a1, _a2, _a3) , _a1, _a2, _a3
308 # define ___ARCH_SI_IA64(_a1, _a2, _a3)
311 int force_sig_fault_to_task(int sig, int code, void __user *addr
312 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
313 , struct task_struct *t);
314 int force_sig_fault(int sig, int code, void __user *addr
315 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr));
316 int send_sig_fault(int sig, int code, void __user *addr
317 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
318 , struct task_struct *t);
320 int force_sig_mceerr(int code, void __user *, short);
321 int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
323 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
324 int force_sig_pkuerr(void __user *addr, u32 pkey);
325 int send_sig_perf(void __user *addr, u32 type, u64 sig_data);
327 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
328 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
329 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
330 struct task_struct *t);
331 int force_sig_seccomp(int syscall, int reason, bool force_coredump);
333 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
334 extern void force_sigsegv(int sig);
335 extern int force_sig_info(struct kernel_siginfo *);
336 extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
337 extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
338 extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
339 const struct cred *);
340 extern int kill_pgrp(struct pid *pid, int sig, int priv);
341 extern int kill_pid(struct pid *pid, int sig, int priv);
342 extern __must_check bool do_notify_parent(struct task_struct *, int);
343 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
344 extern void force_sig(int);
345 extern void force_fatal_sig(int);
346 extern void force_exit_sig(int);
347 extern int send_sig(int, struct task_struct *, int);
348 extern int zap_other_threads(struct task_struct *p);
349 extern struct sigqueue *sigqueue_alloc(void);
350 extern void sigqueue_free(struct sigqueue *);
351 extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
352 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
354 static inline void clear_notify_signal(void)
356 clear_thread_flag(TIF_NOTIFY_SIGNAL);
357 smp_mb__after_atomic();
361 * Returns 'true' if kick_process() is needed to force a transition from
362 * user -> kernel to guarantee expedient run of TWA_SIGNAL based task_work.
364 static inline bool __set_notify_signal(struct task_struct *task)
366 return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) &&
367 !wake_up_state(task, TASK_INTERRUPTIBLE);
371 * Called to break out of interruptible wait loops, and enter the
372 * exit_to_user_mode_loop().
374 static inline void set_notify_signal(struct task_struct *task)
376 if (__set_notify_signal(task))
380 static inline int restart_syscall(void)
382 set_tsk_thread_flag(current, TIF_SIGPENDING);
383 return -ERESTARTNOINTR;
386 static inline int task_sigpending(struct task_struct *p)
388 return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
391 static inline int signal_pending(struct task_struct *p)
394 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
395 * behavior in terms of ensuring that we break out of wait loops
396 * so that notify signal callbacks can be processed.
398 if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
400 return task_sigpending(p);
403 static inline int __fatal_signal_pending(struct task_struct *p)
405 return unlikely(sigismember(&p->pending.signal, SIGKILL));
408 static inline int fatal_signal_pending(struct task_struct *p)
410 return task_sigpending(p) && __fatal_signal_pending(p);
413 static inline int signal_pending_state(unsigned int state, struct task_struct *p)
415 if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
417 if (!signal_pending(p))
420 return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
424 * This should only be used in fault handlers to decide whether we
425 * should stop the current fault routine to handle the signals
426 * instead, especially with the case where we've got interrupted with
429 static inline bool fault_signal_pending(vm_fault_t fault_flags,
430 struct pt_regs *regs)
432 return unlikely((fault_flags & VM_FAULT_RETRY) &&
433 (fatal_signal_pending(current) ||
434 (user_mode(regs) && signal_pending(current))));
438 * Reevaluate whether the task has signals pending delivery.
439 * Wake the task if so.
440 * This is required every time the blocked sigset_t changes.
441 * callers must hold sighand->siglock.
443 extern void recalc_sigpending_and_wake(struct task_struct *t);
444 extern void recalc_sigpending(void);
445 extern void calculate_sigpending(void);
447 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
449 static inline void signal_wake_up(struct task_struct *t, bool fatal)
451 unsigned int state = 0;
452 if (fatal && !(t->jobctl & JOBCTL_PTRACE_FROZEN)) {
453 t->jobctl &= ~(JOBCTL_STOPPED | JOBCTL_TRACED);
454 state = TASK_WAKEKILL | __TASK_TRACED;
456 signal_wake_up_state(t, state);
458 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
460 unsigned int state = 0;
462 t->jobctl &= ~JOBCTL_TRACED;
463 state = __TASK_TRACED;
465 signal_wake_up_state(t, state);
468 void task_join_group_stop(struct task_struct *task);
470 #ifdef TIF_RESTORE_SIGMASK
472 * Legacy restore_sigmask accessors. These are inefficient on
473 * SMP architectures because they require atomic operations.
477 * set_restore_sigmask() - make sure saved_sigmask processing gets done
479 * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
480 * will run before returning to user mode, to process the flag. For
481 * all callers, TIF_SIGPENDING is already set or it's no harm to set
482 * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the
483 * arch code will notice on return to user mode, in case those bits
484 * are scarce. We set TIF_SIGPENDING here to ensure that the arch
485 * signal code always gets run when TIF_RESTORE_SIGMASK is set.
487 static inline void set_restore_sigmask(void)
489 set_thread_flag(TIF_RESTORE_SIGMASK);
492 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
494 clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
497 static inline void clear_restore_sigmask(void)
499 clear_thread_flag(TIF_RESTORE_SIGMASK);
501 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
503 return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
505 static inline bool test_restore_sigmask(void)
507 return test_thread_flag(TIF_RESTORE_SIGMASK);
509 static inline bool test_and_clear_restore_sigmask(void)
511 return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
514 #else /* TIF_RESTORE_SIGMASK */
516 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
517 static inline void set_restore_sigmask(void)
519 current->restore_sigmask = true;
521 static inline void clear_tsk_restore_sigmask(struct task_struct *task)
523 task->restore_sigmask = false;
525 static inline void clear_restore_sigmask(void)
527 current->restore_sigmask = false;
529 static inline bool test_restore_sigmask(void)
531 return current->restore_sigmask;
533 static inline bool test_tsk_restore_sigmask(struct task_struct *task)
535 return task->restore_sigmask;
537 static inline bool test_and_clear_restore_sigmask(void)
539 if (!current->restore_sigmask)
541 current->restore_sigmask = false;
546 static inline void restore_saved_sigmask(void)
548 if (test_and_clear_restore_sigmask())
549 __set_current_blocked(¤t->saved_sigmask);
552 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
554 static inline void restore_saved_sigmask_unless(bool interrupted)
557 WARN_ON(!signal_pending(current));
559 restore_saved_sigmask();
562 static inline sigset_t *sigmask_to_save(void)
564 sigset_t *res = ¤t->blocked;
565 if (unlikely(test_restore_sigmask()))
566 res = ¤t->saved_sigmask;
570 static inline int kill_cad_pid(int sig, int priv)
572 return kill_pid(cad_pid, sig, priv);
575 /* These can be the second arg to send_sig_info/send_group_sig_info. */
576 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
577 #define SEND_SIG_PRIV ((struct kernel_siginfo *) 1)
579 static inline int __on_sig_stack(unsigned long sp)
581 #ifdef CONFIG_STACK_GROWSUP
582 return sp >= current->sas_ss_sp &&
583 sp - current->sas_ss_sp < current->sas_ss_size;
585 return sp > current->sas_ss_sp &&
586 sp - current->sas_ss_sp <= current->sas_ss_size;
591 * True if we are on the alternate signal stack.
593 static inline int on_sig_stack(unsigned long sp)
596 * If the signal stack is SS_AUTODISARM then, by construction, we
597 * can't be on the signal stack unless user code deliberately set
598 * SS_AUTODISARM when we were already on it.
600 * This improves reliability: if user state gets corrupted such that
601 * the stack pointer points very close to the end of the signal stack,
602 * then this check will enable the signal to be handled anyway.
604 if (current->sas_ss_flags & SS_AUTODISARM)
607 return __on_sig_stack(sp);
610 static inline int sas_ss_flags(unsigned long sp)
612 if (!current->sas_ss_size)
615 return on_sig_stack(sp) ? SS_ONSTACK : 0;
618 static inline void sas_ss_reset(struct task_struct *p)
622 p->sas_ss_flags = SS_DISABLE;
625 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
627 if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
628 #ifdef CONFIG_STACK_GROWSUP
629 return current->sas_ss_sp;
631 return current->sas_ss_sp + current->sas_ss_size;
636 extern void __cleanup_sighand(struct sighand_struct *);
637 extern void flush_itimer_signals(void);
639 #define tasklist_empty() \
640 list_empty(&init_task.tasks)
642 #define next_task(p) \
643 list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
645 #define for_each_process(p) \
646 for (p = &init_task ; (p = next_task(p)) != &init_task ; )
648 extern bool current_is_single_threaded(void);
651 * Careful: do_each_thread/while_each_thread is a double loop so
652 * 'break' will not work as expected - use goto instead.
654 #define do_each_thread(g, t) \
655 for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
657 #define while_each_thread(g, t) \
658 while ((t = next_thread(t)) != g)
660 #define __for_each_thread(signal, t) \
661 list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)
663 #define for_each_thread(p, t) \
664 __for_each_thread((p)->signal, t)
666 /* Careful: this is a double loop, 'break' won't work as expected. */
667 #define for_each_process_thread(p, t) \
668 for_each_process(p) for_each_thread(p, t)
670 typedef int (*proc_visitor)(struct task_struct *p, void *data);
671 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
674 struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
677 if (type == PIDTYPE_PID)
678 pid = task_pid(task);
680 pid = task->signal->pids[type];
684 static inline struct pid *task_tgid(struct task_struct *task)
686 return task->signal->pids[PIDTYPE_TGID];
690 * Without tasklist or RCU lock it is not safe to dereference
691 * the result of task_pgrp/task_session even if task == current,
692 * we can race with another thread doing sys_setsid/sys_setpgid.
694 static inline struct pid *task_pgrp(struct task_struct *task)
696 return task->signal->pids[PIDTYPE_PGID];
699 static inline struct pid *task_session(struct task_struct *task)
701 return task->signal->pids[PIDTYPE_SID];
704 static inline int get_nr_threads(struct task_struct *task)
706 return task->signal->nr_threads;
709 static inline bool thread_group_leader(struct task_struct *p)
711 return p->exit_signal >= 0;
715 bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
717 return p1->signal == p2->signal;
720 static inline struct task_struct *next_thread(const struct task_struct *p)
722 return list_entry_rcu(p->thread_group.next,
723 struct task_struct, thread_group);
726 static inline int thread_group_empty(struct task_struct *p)
728 return list_empty(&p->thread_group);
731 #define delay_group_leader(p) \
732 (thread_group_leader(p) && !thread_group_empty(p))
734 extern bool thread_group_exited(struct pid *pid);
736 extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
737 unsigned long *flags);
739 static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
740 unsigned long *flags)
742 struct sighand_struct *ret;
744 ret = __lock_task_sighand(task, flags);
745 (void)__cond_lock(&task->sighand->siglock, ret);
749 static inline void unlock_task_sighand(struct task_struct *task,
750 unsigned long *flags)
752 spin_unlock_irqrestore(&task->sighand->siglock, *flags);
755 #ifdef CONFIG_LOCKDEP
756 extern void lockdep_assert_task_sighand_held(struct task_struct *task);
758 static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { }
761 static inline unsigned long task_rlimit(const struct task_struct *task,
764 return READ_ONCE(task->signal->rlim[limit].rlim_cur);
767 static inline unsigned long task_rlimit_max(const struct task_struct *task,
770 return READ_ONCE(task->signal->rlim[limit].rlim_max);
773 static inline unsigned long rlimit(unsigned int limit)
775 return task_rlimit(current, limit);
778 static inline unsigned long rlimit_max(unsigned int limit)
780 return task_rlimit_max(current, limit);
783 #endif /* _LINUX_SCHED_SIGNAL_H */