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 | struct list_head thread_head; |
98 | |
99 | wait_queue_head_t wait_chldexit; /* for wait4() */ |
100 | |
101 | /* current thread group signal load-balancing target: */ |
102 | struct task_struct *curr_target; |
103 | |
104 | /* shared signal handling: */ |
105 | struct sigpending shared_pending; |
106 | |
107 | /* For collecting multiprocess signals during fork */ |
108 | struct hlist_head multiprocess; |
109 | |
110 | /* thread group exit support */ |
111 | int group_exit_code; |
112 | /* notify group_exec_task when notify_count is less or equal to 0 */ |
113 | int notify_count; |
114 | struct task_struct *group_exec_task; |
115 | |
116 | /* thread group stop support, overloads group_exit_code too */ |
117 | int group_stop_count; |
118 | unsigned int flags; /* see SIGNAL_* flags below */ |
119 | |
120 | struct core_state *core_state; /* coredumping support */ |
121 | |
122 | /* |
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. |
130 | */ |
131 | unsigned int is_child_subreaper:1; |
132 | unsigned int has_child_subreaper:1; |
133 | |
134 | #ifdef CONFIG_POSIX_TIMERS |
135 | |
136 | /* POSIX.1b Interval Timers */ |
137 | int posix_timer_id; |
138 | struct list_head posix_timers; |
139 | |
140 | /* ITIMER_REAL timer for the process */ |
141 | struct hrtimer real_timer; |
142 | ktime_t it_real_incr; |
143 | |
144 | /* |
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 |
148 | */ |
149 | struct cpu_itimer it[2]; |
150 | |
151 | /* |
152 | * Thread group totals for process CPU timers. |
153 | * See thread_group_cputimer(), et al, for details. |
154 | */ |
155 | struct thread_group_cputimer cputimer; |
156 | |
157 | #endif |
158 | /* Empty if CONFIG_POSIX_TIMERS=n */ |
159 | struct posix_cputimers posix_cputimers; |
160 | |
161 | /* PID/PID hash table linkage. */ |
162 | struct pid *pids[PIDTYPE_MAX]; |
163 | |
164 | #ifdef CONFIG_NO_HZ_FULL |
165 | atomic_t tick_dep_mask; |
166 | #endif |
167 | |
168 | struct pid *tty_old_pgrp; |
169 | |
170 | /* boolean value for session group leader */ |
171 | int leader; |
172 | |
173 | struct tty_struct *tty; /* NULL if no tty */ |
174 | |
175 | #ifdef CONFIG_SCHED_AUTOGROUP |
176 | struct autogroup *autogroup; |
177 | #endif |
178 | /* |
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. |
183 | */ |
184 | seqlock_t stats_lock; |
185 | u64 utime, stime, cutime, cstime; |
186 | u64 gtime; |
187 | u64 cgtime; |
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 , ; |
193 | struct task_io_accounting ioac; |
194 | |
195 | /* |
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.) |
200 | */ |
201 | unsigned long long sum_sched_runtime; |
202 | |
203 | /* |
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. |
211 | */ |
212 | struct rlimit rlim[RLIM_NLIMITS]; |
213 | |
214 | #ifdef CONFIG_BSD_PROCESS_ACCT |
215 | struct pacct_struct pacct; /* per-process accounting information */ |
216 | #endif |
217 | #ifdef CONFIG_TASKSTATS |
218 | struct taskstats *stats; |
219 | #endif |
220 | #ifdef CONFIG_AUDIT |
221 | unsigned audit_tty; |
222 | struct tty_audit_buf *tty_audit_buf; |
223 | #endif |
224 | |
225 | /* |
226 | * Thread is the potential origin of an oom condition; kill first on |
227 | * oom |
228 | */ |
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 */ |
235 | |
236 | struct mutex cred_guard_mutex; /* guard against foreign influences on |
237 | * credential calculations |
238 | * (notably. ptrace) |
239 | * Deprecated do not use in new code. |
240 | * Use exec_update_lock instead. |
241 | */ |
242 | struct rw_semaphore exec_update_lock; /* Held while task_struct is |
243 | * being updated during exec, |
244 | * and may have inconsistent |
245 | * permissions. |
246 | */ |
247 | } __randomize_layout; |
248 | |
249 | /* |
250 | * Bits in flags field of signal_struct. |
251 | */ |
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 */ |
255 | /* |
256 | * Pending notifications to parent. |
257 | */ |
258 | #define SIGNAL_CLD_STOPPED 0x00000010 |
259 | #define SIGNAL_CLD_CONTINUED 0x00000020 |
260 | #define SIGNAL_CLD_MASK (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED) |
261 | |
262 | #define SIGNAL_UNKILLABLE 0x00000040 /* for init: ignore fatal signals */ |
263 | |
264 | #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \ |
265 | SIGNAL_STOP_CONTINUED) |
266 | |
267 | static inline void signal_set_stop_flags(struct signal_struct *sig, |
268 | unsigned int flags) |
269 | { |
270 | WARN_ON(sig->flags & SIGNAL_GROUP_EXIT); |
271 | sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags; |
272 | } |
273 | |
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); |
279 | |
280 | static inline int kernel_dequeue_signal(void) |
281 | { |
282 | struct task_struct *task = current; |
283 | kernel_siginfo_t __info; |
284 | enum pid_type __type; |
285 | int ret; |
286 | |
287 | spin_lock_irq(&task->sighand->siglock); |
288 | ret = dequeue_signal(task, &task->blocked, &__info, &__type); |
289 | spin_unlock_irq(&task->sighand->siglock); |
290 | |
291 | return ret; |
292 | } |
293 | |
294 | static inline void kernel_signal_stop(void) |
295 | { |
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); |
300 | } |
301 | spin_unlock_irq(¤t->sighand->siglock); |
302 | |
303 | schedule(); |
304 | } |
305 | #ifdef __ia64__ |
306 | # define ___ARCH_SI_IA64(_a1, _a2, _a3) , _a1, _a2, _a3 |
307 | #else |
308 | # define ___ARCH_SI_IA64(_a1, _a2, _a3) |
309 | #endif |
310 | |
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); |
319 | |
320 | int force_sig_mceerr(int code, void __user *, short); |
321 | int send_sig_mceerr(int code, void __user *, short, struct task_struct *); |
322 | |
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); |
326 | |
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); |
332 | |
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 *); |
353 | |
354 | static inline void clear_notify_signal(void) |
355 | { |
356 | clear_thread_flag(TIF_NOTIFY_SIGNAL); |
357 | smp_mb__after_atomic(); |
358 | } |
359 | |
360 | /* |
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. |
363 | */ |
364 | static inline bool __set_notify_signal(struct task_struct *task) |
365 | { |
366 | return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) && |
367 | !wake_up_state(task, TASK_INTERRUPTIBLE); |
368 | } |
369 | |
370 | /* |
371 | * Called to break out of interruptible wait loops, and enter the |
372 | * exit_to_user_mode_loop(). |
373 | */ |
374 | static inline void set_notify_signal(struct task_struct *task) |
375 | { |
376 | if (__set_notify_signal(task)) |
377 | kick_process(task); |
378 | } |
379 | |
380 | static inline int restart_syscall(void) |
381 | { |
382 | set_tsk_thread_flag(current, TIF_SIGPENDING); |
383 | return -ERESTARTNOINTR; |
384 | } |
385 | |
386 | static inline int task_sigpending(struct task_struct *p) |
387 | { |
388 | return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING)); |
389 | } |
390 | |
391 | static inline int signal_pending(struct task_struct *p) |
392 | { |
393 | /* |
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. |
397 | */ |
398 | if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL))) |
399 | return 1; |
400 | return task_sigpending(p); |
401 | } |
402 | |
403 | static inline int __fatal_signal_pending(struct task_struct *p) |
404 | { |
405 | return unlikely(sigismember(&p->pending.signal, SIGKILL)); |
406 | } |
407 | |
408 | static inline int fatal_signal_pending(struct task_struct *p) |
409 | { |
410 | return task_sigpending(p) && __fatal_signal_pending(p); |
411 | } |
412 | |
413 | static inline int signal_pending_state(unsigned int state, struct task_struct *p) |
414 | { |
415 | if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL))) |
416 | return 0; |
417 | if (!signal_pending(p)) |
418 | return 0; |
419 | |
420 | return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p); |
421 | } |
422 | |
423 | /* |
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 |
427 | * a VM_FAULT_RETRY. |
428 | */ |
429 | static inline bool fault_signal_pending(vm_fault_t fault_flags, |
430 | struct pt_regs *regs) |
431 | { |
432 | return unlikely((fault_flags & VM_FAULT_RETRY) && |
433 | (fatal_signal_pending(current) || |
434 | (user_mode(regs) && signal_pending(current)))); |
435 | } |
436 | |
437 | /* |
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. |
442 | */ |
443 | extern void recalc_sigpending_and_wake(struct task_struct *t); |
444 | extern void recalc_sigpending(void); |
445 | extern void calculate_sigpending(void); |
446 | |
447 | extern void signal_wake_up_state(struct task_struct *t, unsigned int state); |
448 | |
449 | static inline void signal_wake_up(struct task_struct *t, bool fatal) |
450 | { |
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; |
455 | } |
456 | signal_wake_up_state(t, state); |
457 | } |
458 | static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume) |
459 | { |
460 | unsigned int state = 0; |
461 | if (resume) { |
462 | t->jobctl &= ~JOBCTL_TRACED; |
463 | state = __TASK_TRACED; |
464 | } |
465 | signal_wake_up_state(t, state); |
466 | } |
467 | |
468 | void task_join_group_stop(struct task_struct *task); |
469 | |
470 | #ifdef TIF_RESTORE_SIGMASK |
471 | /* |
472 | * Legacy restore_sigmask accessors. These are inefficient on |
473 | * SMP architectures because they require atomic operations. |
474 | */ |
475 | |
476 | /** |
477 | * set_restore_sigmask() - make sure saved_sigmask processing gets done |
478 | * |
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. |
486 | */ |
487 | static inline void set_restore_sigmask(void) |
488 | { |
489 | set_thread_flag(TIF_RESTORE_SIGMASK); |
490 | } |
491 | |
492 | static inline void clear_tsk_restore_sigmask(struct task_struct *task) |
493 | { |
494 | clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK); |
495 | } |
496 | |
497 | static inline void clear_restore_sigmask(void) |
498 | { |
499 | clear_thread_flag(TIF_RESTORE_SIGMASK); |
500 | } |
501 | static inline bool test_tsk_restore_sigmask(struct task_struct *task) |
502 | { |
503 | return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK); |
504 | } |
505 | static inline bool test_restore_sigmask(void) |
506 | { |
507 | return test_thread_flag(TIF_RESTORE_SIGMASK); |
508 | } |
509 | static inline bool test_and_clear_restore_sigmask(void) |
510 | { |
511 | return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK); |
512 | } |
513 | |
514 | #else /* TIF_RESTORE_SIGMASK */ |
515 | |
516 | /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */ |
517 | static inline void set_restore_sigmask(void) |
518 | { |
519 | current->restore_sigmask = true; |
520 | } |
521 | static inline void clear_tsk_restore_sigmask(struct task_struct *task) |
522 | { |
523 | task->restore_sigmask = false; |
524 | } |
525 | static inline void clear_restore_sigmask(void) |
526 | { |
527 | current->restore_sigmask = false; |
528 | } |
529 | static inline bool test_restore_sigmask(void) |
530 | { |
531 | return current->restore_sigmask; |
532 | } |
533 | static inline bool test_tsk_restore_sigmask(struct task_struct *task) |
534 | { |
535 | return task->restore_sigmask; |
536 | } |
537 | static inline bool test_and_clear_restore_sigmask(void) |
538 | { |
539 | if (!current->restore_sigmask) |
540 | return false; |
541 | current->restore_sigmask = false; |
542 | return true; |
543 | } |
544 | #endif |
545 | |
546 | static inline void restore_saved_sigmask(void) |
547 | { |
548 | if (test_and_clear_restore_sigmask()) |
549 | __set_current_blocked(¤t->saved_sigmask); |
550 | } |
551 | |
552 | extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize); |
553 | |
554 | static inline void restore_saved_sigmask_unless(bool interrupted) |
555 | { |
556 | if (interrupted) |
557 | WARN_ON(!signal_pending(current)); |
558 | else |
559 | restore_saved_sigmask(); |
560 | } |
561 | |
562 | static inline sigset_t *sigmask_to_save(void) |
563 | { |
564 | sigset_t *res = ¤t->blocked; |
565 | if (unlikely(test_restore_sigmask())) |
566 | res = ¤t->saved_sigmask; |
567 | return res; |
568 | } |
569 | |
570 | static inline int kill_cad_pid(int sig, int priv) |
571 | { |
572 | return kill_pid(cad_pid, sig, priv); |
573 | } |
574 | |
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) |
578 | |
579 | static inline int __on_sig_stack(unsigned long sp) |
580 | { |
581 | #ifdef CONFIG_STACK_GROWSUP |
582 | return sp >= current->sas_ss_sp && |
583 | sp - current->sas_ss_sp < current->sas_ss_size; |
584 | #else |
585 | return sp > current->sas_ss_sp && |
586 | sp - current->sas_ss_sp <= current->sas_ss_size; |
587 | #endif |
588 | } |
589 | |
590 | /* |
591 | * True if we are on the alternate signal stack. |
592 | */ |
593 | static inline int on_sig_stack(unsigned long sp) |
594 | { |
595 | /* |
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. |
599 | * |
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. |
603 | */ |
604 | if (current->sas_ss_flags & SS_AUTODISARM) |
605 | return 0; |
606 | |
607 | return __on_sig_stack(sp); |
608 | } |
609 | |
610 | static inline int sas_ss_flags(unsigned long sp) |
611 | { |
612 | if (!current->sas_ss_size) |
613 | return SS_DISABLE; |
614 | |
615 | return on_sig_stack(sp) ? SS_ONSTACK : 0; |
616 | } |
617 | |
618 | static inline void sas_ss_reset(struct task_struct *p) |
619 | { |
620 | p->sas_ss_sp = 0; |
621 | p->sas_ss_size = 0; |
622 | p->sas_ss_flags = SS_DISABLE; |
623 | } |
624 | |
625 | static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig) |
626 | { |
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; |
630 | #else |
631 | return current->sas_ss_sp + current->sas_ss_size; |
632 | #endif |
633 | return sp; |
634 | } |
635 | |
636 | extern void __cleanup_sighand(struct sighand_struct *); |
637 | extern void flush_itimer_signals(void); |
638 | |
639 | #define tasklist_empty() \ |
640 | list_empty(&init_task.tasks) |
641 | |
642 | #define next_task(p) \ |
643 | list_entry_rcu((p)->tasks.next, struct task_struct, tasks) |
644 | |
645 | #define for_each_process(p) \ |
646 | for (p = &init_task ; (p = next_task(p)) != &init_task ; ) |
647 | |
648 | extern bool current_is_single_threaded(void); |
649 | |
650 | /* |
651 | * Careful: do_each_thread/while_each_thread is a double loop so |
652 | * 'break' will not work as expected - use goto instead. |
653 | */ |
654 | #define do_each_thread(g, t) \ |
655 | for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do |
656 | |
657 | #define while_each_thread(g, t) \ |
658 | while ((t = next_thread(t)) != g) |
659 | |
660 | #define __for_each_thread(signal, t) \ |
661 | list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node) |
662 | |
663 | #define for_each_thread(p, t) \ |
664 | __for_each_thread((p)->signal, t) |
665 | |
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) |
669 | |
670 | typedef int (*proc_visitor)(struct task_struct *p, void *data); |
671 | void walk_process_tree(struct task_struct *top, proc_visitor, void *); |
672 | |
673 | static inline |
674 | struct pid *task_pid_type(struct task_struct *task, enum pid_type type) |
675 | { |
676 | struct pid *pid; |
677 | if (type == PIDTYPE_PID) |
678 | pid = task_pid(task); |
679 | else |
680 | pid = task->signal->pids[type]; |
681 | return pid; |
682 | } |
683 | |
684 | static inline struct pid *task_tgid(struct task_struct *task) |
685 | { |
686 | return task->signal->pids[PIDTYPE_TGID]; |
687 | } |
688 | |
689 | /* |
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. |
693 | */ |
694 | static inline struct pid *task_pgrp(struct task_struct *task) |
695 | { |
696 | return task->signal->pids[PIDTYPE_PGID]; |
697 | } |
698 | |
699 | static inline struct pid *task_session(struct task_struct *task) |
700 | { |
701 | return task->signal->pids[PIDTYPE_SID]; |
702 | } |
703 | |
704 | static inline int get_nr_threads(struct task_struct *task) |
705 | { |
706 | return task->signal->nr_threads; |
707 | } |
708 | |
709 | static inline bool thread_group_leader(struct task_struct *p) |
710 | { |
711 | return p->exit_signal >= 0; |
712 | } |
713 | |
714 | static inline |
715 | bool same_thread_group(struct task_struct *p1, struct task_struct *p2) |
716 | { |
717 | return p1->signal == p2->signal; |
718 | } |
719 | |
720 | static inline struct task_struct *next_thread(const struct task_struct *p) |
721 | { |
722 | return list_entry_rcu(p->thread_group.next, |
723 | struct task_struct, thread_group); |
724 | } |
725 | |
726 | static inline int thread_group_empty(struct task_struct *p) |
727 | { |
728 | return list_empty(&p->thread_group); |
729 | } |
730 | |
731 | #define delay_group_leader(p) \ |
732 | (thread_group_leader(p) && !thread_group_empty(p)) |
733 | |
734 | extern bool thread_group_exited(struct pid *pid); |
735 | |
736 | extern struct sighand_struct *__lock_task_sighand(struct task_struct *task, |
737 | unsigned long *flags); |
738 | |
739 | static inline struct sighand_struct *lock_task_sighand(struct task_struct *task, |
740 | unsigned long *flags) |
741 | { |
742 | struct sighand_struct *ret; |
743 | |
744 | ret = __lock_task_sighand(task, flags); |
745 | (void)__cond_lock(&task->sighand->siglock, ret); |
746 | return ret; |
747 | } |
748 | |
749 | static inline void unlock_task_sighand(struct task_struct *task, |
750 | unsigned long *flags) |
751 | { |
752 | spin_unlock_irqrestore(&task->sighand->siglock, *flags); |
753 | } |
754 | |
755 | #ifdef CONFIG_LOCKDEP |
756 | extern void lockdep_assert_task_sighand_held(struct task_struct *task); |
757 | #else |
758 | static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { } |
759 | #endif |
760 | |
761 | static inline unsigned long task_rlimit(const struct task_struct *task, |
762 | unsigned int limit) |
763 | { |
764 | return READ_ONCE(task->signal->rlim[limit].rlim_cur); |
765 | } |
766 | |
767 | static inline unsigned long task_rlimit_max(const struct task_struct *task, |
768 | unsigned int limit) |
769 | { |
770 | return READ_ONCE(task->signal->rlim[limit].rlim_max); |
771 | } |
772 | |
773 | static inline unsigned long rlimit(unsigned int limit) |
774 | { |
775 | return task_rlimit(current, limit); |
776 | } |
777 | |
778 | static inline unsigned long rlimit_max(unsigned int limit) |
779 | { |
780 | return task_rlimit_max(current, limit); |
781 | } |
782 | |
783 | #endif /* _LINUX_SCHED_SIGNAL_H */ |
784 | |