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>
14 * Types defining task->signal and task->sighand and APIs using them:
17 struct sighand_struct {
19 struct k_sigaction action[_NSIG];
21 wait_queue_head_t signalfd_wqh;
25 * Per-process accounting stats:
31 u64 ac_utime, ac_stime;
32 unsigned long ac_minflt, ac_majflt;
41 * This is the atomic variant of task_cputime, which can be used for
42 * storing and updating task_cputime statistics without locking.
44 struct task_cputime_atomic {
47 atomic64_t sum_exec_runtime;
50 #define INIT_CPUTIME_ATOMIC \
51 (struct task_cputime_atomic) { \
52 .utime = ATOMIC64_INIT(0), \
53 .stime = ATOMIC64_INIT(0), \
54 .sum_exec_runtime = ATOMIC64_INIT(0), \
57 * struct thread_group_cputimer - thread group interval timer counts
58 * @cputime_atomic: atomic thread group interval timers.
59 * @running: true when there are timers running and
60 * @cputime_atomic receives updates.
61 * @checking_timer: true when a thread in the group is in the
62 * process of checking for thread group timers.
64 * This structure contains the version of task_cputime, above, that is
65 * used for thread group CPU timer calculations.
67 struct thread_group_cputimer {
68 struct task_cputime_atomic cputime_atomic;
73 struct multiprocess_signals {
75 struct hlist_node node;
79 * NOTE! "signal_struct" does not have its own
80 * locking, because a shared signal_struct always
81 * implies a shared sighand_struct, so locking
82 * sighand_struct is always a proper superset of
83 * the locking of signal_struct.
85 struct signal_struct {
89 struct list_head thread_head;
91 wait_queue_head_t wait_chldexit; /* for wait4() */
93 /* current thread group signal load-balancing target: */
94 struct task_struct *curr_target;
96 /* shared signal handling: */
97 struct sigpending shared_pending;
99 /* For collecting multiprocess signals during fork */
100 struct hlist_head multiprocess;
102 /* thread group exit support */
105 * - notify group_exit_task when ->count is equal to notify_count
106 * - everyone except group_exit_task is stopped during signal delivery
107 * of fatal signals, group_exit_task processes the signal.
110 struct task_struct *group_exit_task;
112 /* thread group stop support, overloads group_exit_code too */
113 int group_stop_count;
114 unsigned int flags; /* see SIGNAL_* flags below */
117 * PR_SET_CHILD_SUBREAPER marks a process, like a service
118 * manager, to re-parent orphan (double-forking) child processes
119 * to this process instead of 'init'. The service manager is
120 * able to receive SIGCHLD signals and is able to investigate
121 * the process until it calls wait(). All children of this
122 * process will inherit a flag if they should look for a
123 * child_subreaper process at exit.
125 unsigned int is_child_subreaper:1;
126 unsigned int has_child_subreaper:1;
128 #ifdef CONFIG_POSIX_TIMERS
130 /* POSIX.1b Interval Timers */
132 struct list_head posix_timers;
134 /* ITIMER_REAL timer for the process */
135 struct hrtimer real_timer;
136 ktime_t it_real_incr;
139 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
140 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
141 * values are defined to 0 and 1 respectively
143 struct cpu_itimer it[2];
146 * Thread group totals for process CPU timers.
147 * See thread_group_cputimer(), et al, for details.
149 struct thread_group_cputimer cputimer;
151 /* Earliest-expiration cache. */
152 struct task_cputime cputime_expires;
154 struct list_head cpu_timers[3];
158 /* PID/PID hash table linkage. */
159 struct pid *pids[PIDTYPE_MAX];
161 #ifdef CONFIG_NO_HZ_FULL
162 atomic_t tick_dep_mask;
165 struct pid *tty_old_pgrp;
167 /* boolean value for session group leader */
170 struct tty_struct *tty; /* NULL if no tty */
172 #ifdef CONFIG_SCHED_AUTOGROUP
173 struct autogroup *autogroup;
176 * Cumulative resource counters for dead threads in the group,
177 * and for reaped dead child processes forked by this group.
178 * Live threads maintain their own counters and add to these
179 * in __exit_signal, except for the group leader.
181 seqlock_t stats_lock;
182 u64 utime, stime, cutime, cstime;
185 struct prev_cputime prev_cputime;
186 unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
187 unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
188 unsigned long inblock, oublock, cinblock, coublock;
189 unsigned long maxrss, cmaxrss;
190 struct task_io_accounting ioac;
193 * Cumulative ns of schedule CPU time fo dead threads in the
194 * group, not including a zombie group leader, (This only differs
195 * from jiffies_to_ns(utime + stime) if sched_clock uses something
196 * other than jiffies.)
198 unsigned long long sum_sched_runtime;
201 * We don't bother to synchronize most readers of this at all,
202 * because there is no reader checking a limit that actually needs
203 * to get both rlim_cur and rlim_max atomically, and either one
204 * alone is a single word that can safely be read normally.
205 * getrlimit/setrlimit use task_lock(current->group_leader) to
206 * protect this instead of the siglock, because they really
207 * have no need to disable irqs.
209 struct rlimit rlim[RLIM_NLIMITS];
211 #ifdef CONFIG_BSD_PROCESS_ACCT
212 struct pacct_struct pacct; /* per-process accounting information */
214 #ifdef CONFIG_TASKSTATS
215 struct taskstats *stats;
219 struct tty_audit_buf *tty_audit_buf;
223 * Thread is the potential origin of an oom condition; kill first on
226 bool oom_flag_origin;
227 short oom_score_adj; /* OOM kill score adjustment */
228 short oom_score_adj_min; /* OOM kill score adjustment min value.
229 * Only settable by CAP_SYS_RESOURCE. */
230 struct mm_struct *oom_mm; /* recorded mm when the thread group got
231 * killed by the oom killer */
233 struct mutex cred_guard_mutex; /* guard against foreign influences on
234 * credential calculations
235 * (notably. ptrace) */
236 } __randomize_layout;
239 * Bits in flags field of signal_struct.
241 #define SIGNAL_STOP_STOPPED 0x00000001 /* job control stop in effect */
242 #define SIGNAL_STOP_CONTINUED 0x00000002 /* SIGCONT since WCONTINUED reap */
243 #define SIGNAL_GROUP_EXIT 0x00000004 /* group exit in progress */
244 #define SIGNAL_GROUP_COREDUMP 0x00000008 /* coredump in progress */
246 * Pending notifications to parent.
248 #define SIGNAL_CLD_STOPPED 0x00000010
249 #define SIGNAL_CLD_CONTINUED 0x00000020
250 #define SIGNAL_CLD_MASK (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
252 #define SIGNAL_UNKILLABLE 0x00000040 /* for init: ignore fatal signals */
254 #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
255 SIGNAL_STOP_CONTINUED)
257 static inline void signal_set_stop_flags(struct signal_struct *sig,
260 WARN_ON(sig->flags & (SIGNAL_GROUP_EXIT|SIGNAL_GROUP_COREDUMP));
261 sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
264 /* If true, all threads except ->group_exit_task have pending SIGKILL */
265 static inline int signal_group_exit(const struct signal_struct *sig)
267 return (sig->flags & SIGNAL_GROUP_EXIT) ||
268 (sig->group_exit_task != NULL);
271 extern void flush_signals(struct task_struct *);
272 extern void ignore_signals(struct task_struct *);
273 extern void flush_signal_handlers(struct task_struct *, int force_default);
274 extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info);
276 static inline int kernel_dequeue_signal(void)
278 struct task_struct *tsk = current;
279 kernel_siginfo_t __info;
282 spin_lock_irq(&tsk->sighand->siglock);
283 ret = dequeue_signal(tsk, &tsk->blocked, &__info);
284 spin_unlock_irq(&tsk->sighand->siglock);
289 static inline void kernel_signal_stop(void)
291 spin_lock_irq(¤t->sighand->siglock);
292 if (current->jobctl & JOBCTL_STOP_DEQUEUED)
293 set_special_state(TASK_STOPPED);
294 spin_unlock_irq(¤t->sighand->siglock);
298 #ifdef __ARCH_SI_TRAPNO
299 # define ___ARCH_SI_TRAPNO(_a1) , _a1
301 # define ___ARCH_SI_TRAPNO(_a1)
304 # define ___ARCH_SI_IA64(_a1, _a2, _a3) , _a1, _a2, _a3
306 # define ___ARCH_SI_IA64(_a1, _a2, _a3)
309 int force_sig_fault(int sig, int code, void __user *addr
310 ___ARCH_SI_TRAPNO(int trapno)
311 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
312 , struct task_struct *t);
313 int send_sig_fault(int sig, int code, void __user *addr
314 ___ARCH_SI_TRAPNO(int trapno)
315 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
316 , struct task_struct *t);
318 int force_sig_mceerr(int code, void __user *, short, struct task_struct *);
319 int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
321 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
322 int force_sig_pkuerr(void __user *addr, u32 pkey);
324 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
326 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
327 extern void force_sigsegv(int sig, struct task_struct *p);
328 extern int force_sig_info(int, struct kernel_siginfo *, struct task_struct *);
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_info_as_cred(int, struct kernel_siginfo *, 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, struct task_struct *);
338 extern int send_sig(int, struct task_struct *, int);
339 extern int zap_other_threads(struct task_struct *p);
340 extern struct sigqueue *sigqueue_alloc(void);
341 extern void sigqueue_free(struct sigqueue *);
342 extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
343 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
345 static inline int restart_syscall(void)
347 set_tsk_thread_flag(current, TIF_SIGPENDING);
348 return -ERESTARTNOINTR;
351 static inline int signal_pending(struct task_struct *p)
353 return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
356 static inline int __fatal_signal_pending(struct task_struct *p)
358 return unlikely(sigismember(&p->pending.signal, SIGKILL));
361 static inline int fatal_signal_pending(struct task_struct *p)
363 return signal_pending(p) && __fatal_signal_pending(p);
366 static inline int signal_pending_state(long state, struct task_struct *p)
368 if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
370 if (!signal_pending(p))
373 return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
377 * Reevaluate whether the task has signals pending delivery.
378 * Wake the task if so.
379 * This is required every time the blocked sigset_t changes.
380 * callers must hold sighand->siglock.
382 extern void recalc_sigpending_and_wake(struct task_struct *t);
383 extern void recalc_sigpending(void);
384 extern void calculate_sigpending(void);
386 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
388 static inline void signal_wake_up(struct task_struct *t, bool resume)
390 signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
392 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
394 signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
397 void task_join_group_stop(struct task_struct *task);
399 #ifdef TIF_RESTORE_SIGMASK
401 * Legacy restore_sigmask accessors. These are inefficient on
402 * SMP architectures because they require atomic operations.
406 * set_restore_sigmask() - make sure saved_sigmask processing gets done
408 * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
409 * will run before returning to user mode, to process the flag. For
410 * all callers, TIF_SIGPENDING is already set or it's no harm to set
411 * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the
412 * arch code will notice on return to user mode, in case those bits
413 * are scarce. We set TIF_SIGPENDING here to ensure that the arch
414 * signal code always gets run when TIF_RESTORE_SIGMASK is set.
416 static inline void set_restore_sigmask(void)
418 set_thread_flag(TIF_RESTORE_SIGMASK);
419 WARN_ON(!test_thread_flag(TIF_SIGPENDING));
422 static inline void clear_tsk_restore_sigmask(struct task_struct *tsk)
424 clear_tsk_thread_flag(tsk, TIF_RESTORE_SIGMASK);
427 static inline void clear_restore_sigmask(void)
429 clear_thread_flag(TIF_RESTORE_SIGMASK);
431 static inline bool test_tsk_restore_sigmask(struct task_struct *tsk)
433 return test_tsk_thread_flag(tsk, TIF_RESTORE_SIGMASK);
435 static inline bool test_restore_sigmask(void)
437 return test_thread_flag(TIF_RESTORE_SIGMASK);
439 static inline bool test_and_clear_restore_sigmask(void)
441 return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
444 #else /* TIF_RESTORE_SIGMASK */
446 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
447 static inline void set_restore_sigmask(void)
449 current->restore_sigmask = true;
450 WARN_ON(!test_thread_flag(TIF_SIGPENDING));
452 static inline void clear_tsk_restore_sigmask(struct task_struct *tsk)
454 tsk->restore_sigmask = false;
456 static inline void clear_restore_sigmask(void)
458 current->restore_sigmask = false;
460 static inline bool test_restore_sigmask(void)
462 return current->restore_sigmask;
464 static inline bool test_tsk_restore_sigmask(struct task_struct *tsk)
466 return tsk->restore_sigmask;
468 static inline bool test_and_clear_restore_sigmask(void)
470 if (!current->restore_sigmask)
472 current->restore_sigmask = false;
477 static inline void restore_saved_sigmask(void)
479 if (test_and_clear_restore_sigmask())
480 __set_current_blocked(¤t->saved_sigmask);
483 static inline sigset_t *sigmask_to_save(void)
485 sigset_t *res = ¤t->blocked;
486 if (unlikely(test_restore_sigmask()))
487 res = ¤t->saved_sigmask;
491 static inline int kill_cad_pid(int sig, int priv)
493 return kill_pid(cad_pid, sig, priv);
496 /* These can be the second arg to send_sig_info/send_group_sig_info. */
497 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
498 #define SEND_SIG_PRIV ((struct kernel_siginfo *) 1)
501 * True if we are on the alternate signal stack.
503 static inline int on_sig_stack(unsigned long sp)
506 * If the signal stack is SS_AUTODISARM then, by construction, we
507 * can't be on the signal stack unless user code deliberately set
508 * SS_AUTODISARM when we were already on it.
510 * This improves reliability: if user state gets corrupted such that
511 * the stack pointer points very close to the end of the signal stack,
512 * then this check will enable the signal to be handled anyway.
514 if (current->sas_ss_flags & SS_AUTODISARM)
517 #ifdef CONFIG_STACK_GROWSUP
518 return sp >= current->sas_ss_sp &&
519 sp - current->sas_ss_sp < current->sas_ss_size;
521 return sp > current->sas_ss_sp &&
522 sp - current->sas_ss_sp <= current->sas_ss_size;
526 static inline int sas_ss_flags(unsigned long sp)
528 if (!current->sas_ss_size)
531 return on_sig_stack(sp) ? SS_ONSTACK : 0;
534 static inline void sas_ss_reset(struct task_struct *p)
538 p->sas_ss_flags = SS_DISABLE;
541 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
543 if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
544 #ifdef CONFIG_STACK_GROWSUP
545 return current->sas_ss_sp;
547 return current->sas_ss_sp + current->sas_ss_size;
552 extern void __cleanup_sighand(struct sighand_struct *);
553 extern void flush_itimer_signals(void);
555 #define tasklist_empty() \
556 list_empty(&init_task.tasks)
558 #define next_task(p) \
559 list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
561 #define for_each_process(p) \
562 for (p = &init_task ; (p = next_task(p)) != &init_task ; )
564 extern bool current_is_single_threaded(void);
567 * Careful: do_each_thread/while_each_thread is a double loop so
568 * 'break' will not work as expected - use goto instead.
570 #define do_each_thread(g, t) \
571 for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
573 #define while_each_thread(g, t) \
574 while ((t = next_thread(t)) != g)
576 #define __for_each_thread(signal, t) \
577 list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)
579 #define for_each_thread(p, t) \
580 __for_each_thread((p)->signal, t)
582 /* Careful: this is a double loop, 'break' won't work as expected. */
583 #define for_each_process_thread(p, t) \
584 for_each_process(p) for_each_thread(p, t)
586 typedef int (*proc_visitor)(struct task_struct *p, void *data);
587 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
590 struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
593 if (type == PIDTYPE_PID)
594 pid = task_pid(task);
596 pid = task->signal->pids[type];
600 static inline struct pid *task_tgid(struct task_struct *task)
602 return task->signal->pids[PIDTYPE_TGID];
606 * Without tasklist or RCU lock it is not safe to dereference
607 * the result of task_pgrp/task_session even if task == current,
608 * we can race with another thread doing sys_setsid/sys_setpgid.
610 static inline struct pid *task_pgrp(struct task_struct *task)
612 return task->signal->pids[PIDTYPE_PGID];
615 static inline struct pid *task_session(struct task_struct *task)
617 return task->signal->pids[PIDTYPE_SID];
620 static inline int get_nr_threads(struct task_struct *tsk)
622 return tsk->signal->nr_threads;
625 static inline bool thread_group_leader(struct task_struct *p)
627 return p->exit_signal >= 0;
630 /* Do to the insanities of de_thread it is possible for a process
631 * to have the pid of the thread group leader without actually being
632 * the thread group leader. For iteration through the pids in proc
633 * all we care about is that we have a task with the appropriate
634 * pid, we don't actually care if we have the right task.
636 static inline bool has_group_leader_pid(struct task_struct *p)
638 return task_pid(p) == task_tgid(p);
642 bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
644 return p1->signal == p2->signal;
647 static inline struct task_struct *next_thread(const struct task_struct *p)
649 return list_entry_rcu(p->thread_group.next,
650 struct task_struct, thread_group);
653 static inline int thread_group_empty(struct task_struct *p)
655 return list_empty(&p->thread_group);
658 #define delay_group_leader(p) \
659 (thread_group_leader(p) && !thread_group_empty(p))
661 extern struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
662 unsigned long *flags);
664 static inline struct sighand_struct *lock_task_sighand(struct task_struct *tsk,
665 unsigned long *flags)
667 struct sighand_struct *ret;
669 ret = __lock_task_sighand(tsk, flags);
670 (void)__cond_lock(&tsk->sighand->siglock, ret);
674 static inline void unlock_task_sighand(struct task_struct *tsk,
675 unsigned long *flags)
677 spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
680 static inline unsigned long task_rlimit(const struct task_struct *tsk,
683 return READ_ONCE(tsk->signal->rlim[limit].rlim_cur);
686 static inline unsigned long task_rlimit_max(const struct task_struct *tsk,
689 return READ_ONCE(tsk->signal->rlim[limit].rlim_max);
692 static inline unsigned long rlimit(unsigned int limit)
694 return task_rlimit(current, limit);
697 static inline unsigned long rlimit_max(unsigned int limit)
699 return task_rlimit_max(current, limit);
702 #endif /* _LINUX_SCHED_SIGNAL_H */