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/pid.h> 13 #include <linux/posix-timers.h> 14 #include <linux/mm_types.h> 15 #include <asm/ptrace.h> 16 17 /* 18 * Types defining task->signal and task->sighand and APIs using them: 19 */ 20 21 struct sighand_struct { 22 spinlock_t siglock; 23 refcount_t count; 24 wait_queue_head_t signalfd_wqh; 25 struct k_sigaction action[_NSIG]; 26 }; 27 28 /* 29 * Per-process accounting stats: 30 */ 31 struct pacct_struct { 32 int ac_flag; 33 long ac_exitcode; 34 unsigned long ac_mem; 35 u64 ac_utime, ac_stime; 36 unsigned long ac_minflt, ac_majflt; 37 }; 38 39 struct cpu_itimer { 40 u64 expires; 41 u64 incr; 42 }; 43 44 /* 45 * This is the atomic variant of task_cputime, which can be used for 46 * storing and updating task_cputime statistics without locking. 47 */ 48 struct task_cputime_atomic { 49 atomic64_t utime; 50 atomic64_t stime; 51 atomic64_t sum_exec_runtime; 52 }; 53 54 #define INIT_CPUTIME_ATOMIC \ 55 (struct task_cputime_atomic) { \ 56 .utime = ATOMIC64_INIT(0), \ 57 .stime = ATOMIC64_INIT(0), \ 58 .sum_exec_runtime = ATOMIC64_INIT(0), \ 59 } 60 /** 61 * struct thread_group_cputimer - thread group interval timer counts 62 * @cputime_atomic: atomic thread group interval timers. 63 * 64 * This structure contains the version of task_cputime, above, that is 65 * used for thread group CPU timer calculations. 66 */ 67 struct thread_group_cputimer { 68 struct task_cputime_atomic cputime_atomic; 69 }; 70 71 struct multiprocess_signals { 72 sigset_t signal; 73 struct hlist_node node; 74 }; 75 76 struct core_thread { 77 struct task_struct *task; 78 struct core_thread *next; 79 }; 80 81 struct core_state { 82 atomic_t nr_threads; 83 struct core_thread dumper; 84 struct completion startup; 85 }; 86 87 /* 88 * NOTE! "signal_struct" does not have its own 89 * locking, because a shared signal_struct always 90 * implies a shared sighand_struct, so locking 91 * sighand_struct is always a proper superset of 92 * the locking of signal_struct. 93 */ 94 struct signal_struct { 95 refcount_t sigcnt; 96 atomic_t live; 97 int nr_threads; 98 int quick_threads; 99 struct list_head thread_head; 100 101 wait_queue_head_t wait_chldexit; /* for wait4() */ 102 103 /* current thread group signal load-balancing target: */ 104 struct task_struct *curr_target; 105 106 /* shared signal handling: */ 107 struct sigpending shared_pending; 108 109 /* For collecting multiprocess signals during fork */ 110 struct hlist_head multiprocess; 111 112 /* thread group exit support */ 113 int group_exit_code; 114 /* notify group_exec_task when notify_count is less or equal to 0 */ 115 int notify_count; 116 struct task_struct *group_exec_task; 117 118 /* thread group stop support, overloads group_exit_code too */ 119 int group_stop_count; 120 unsigned int flags; /* see SIGNAL_* flags below */ 121 122 struct core_state *core_state; /* coredumping support */ 123 124 /* 125 * PR_SET_CHILD_SUBREAPER marks a process, like a service 126 * manager, to re-parent orphan (double-forking) child processes 127 * to this process instead of 'init'. The service manager is 128 * able to receive SIGCHLD signals and is able to investigate 129 * the process until it calls wait(). All children of this 130 * process will inherit a flag if they should look for a 131 * child_subreaper process at exit. 132 */ 133 unsigned int is_child_subreaper:1; 134 unsigned int has_child_subreaper:1; 135 136 #ifdef CONFIG_POSIX_TIMERS 137 138 /* POSIX.1b Interval Timers */ 139 unsigned int next_posix_timer_id; 140 struct list_head posix_timers; 141 142 /* ITIMER_REAL timer for the process */ 143 struct hrtimer real_timer; 144 ktime_t it_real_incr; 145 146 /* 147 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use 148 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these 149 * values are defined to 0 and 1 respectively 150 */ 151 struct cpu_itimer it[2]; 152 153 /* 154 * Thread group totals for process CPU timers. 155 * See thread_group_cputimer(), et al, for details. 156 */ 157 struct thread_group_cputimer cputimer; 158 159 #endif 160 /* Empty if CONFIG_POSIX_TIMERS=n */ 161 struct posix_cputimers posix_cputimers; 162 163 /* PID/PID hash table linkage. */ 164 struct pid *pids[PIDTYPE_MAX]; 165 166 #ifdef CONFIG_NO_HZ_FULL 167 atomic_t tick_dep_mask; 168 #endif 169 170 struct pid *tty_old_pgrp; 171 172 /* boolean value for session group leader */ 173 int leader; 174 175 struct tty_struct *tty; /* NULL if no tty */ 176 177 #ifdef CONFIG_SCHED_AUTOGROUP 178 struct autogroup *autogroup; 179 #endif 180 /* 181 * Cumulative resource counters for dead threads in the group, 182 * and for reaped dead child processes forked by this group. 183 * Live threads maintain their own counters and add to these 184 * in __exit_signal, except for the group leader. 185 */ 186 seqlock_t stats_lock; 187 u64 utime, stime, cutime, cstime; 188 u64 gtime; 189 u64 cgtime; 190 struct prev_cputime prev_cputime; 191 unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw; 192 unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt; 193 unsigned long inblock, oublock, cinblock, coublock; 194 unsigned long maxrss, cmaxrss; 195 struct task_io_accounting ioac; 196 197 /* 198 * Cumulative ns of schedule CPU time fo dead threads in the 199 * group, not including a zombie group leader, (This only differs 200 * from jiffies_to_ns(utime + stime) if sched_clock uses something 201 * other than jiffies.) 202 */ 203 unsigned long long sum_sched_runtime; 204 205 /* 206 * We don't bother to synchronize most readers of this at all, 207 * because there is no reader checking a limit that actually needs 208 * to get both rlim_cur and rlim_max atomically, and either one 209 * alone is a single word that can safely be read normally. 210 * getrlimit/setrlimit use task_lock(current->group_leader) to 211 * protect this instead of the siglock, because they really 212 * have no need to disable irqs. 213 */ 214 struct rlimit rlim[RLIM_NLIMITS]; 215 216 #ifdef CONFIG_BSD_PROCESS_ACCT 217 struct pacct_struct pacct; /* per-process accounting information */ 218 #endif 219 #ifdef CONFIG_TASKSTATS 220 struct taskstats *stats; 221 #endif 222 #ifdef CONFIG_AUDIT 223 unsigned audit_tty; 224 struct tty_audit_buf *tty_audit_buf; 225 #endif 226 227 /* 228 * Thread is the potential origin of an oom condition; kill first on 229 * oom 230 */ 231 bool oom_flag_origin; 232 short oom_score_adj; /* OOM kill score adjustment */ 233 short oom_score_adj_min; /* OOM kill score adjustment min value. 234 * Only settable by CAP_SYS_RESOURCE. */ 235 struct mm_struct *oom_mm; /* recorded mm when the thread group got 236 * killed by the oom killer */ 237 238 struct mutex cred_guard_mutex; /* guard against foreign influences on 239 * credential calculations 240 * (notably. ptrace) 241 * Deprecated do not use in new code. 242 * Use exec_update_lock instead. 243 */ 244 struct rw_semaphore exec_update_lock; /* Held while task_struct is 245 * being updated during exec, 246 * and may have inconsistent 247 * permissions. 248 */ 249 } __randomize_layout; 250 251 /* 252 * Bits in flags field of signal_struct. 253 */ 254 #define SIGNAL_STOP_STOPPED 0x00000001 /* job control stop in effect */ 255 #define SIGNAL_STOP_CONTINUED 0x00000002 /* SIGCONT since WCONTINUED reap */ 256 #define SIGNAL_GROUP_EXIT 0x00000004 /* group exit in progress */ 257 /* 258 * Pending notifications to parent. 259 */ 260 #define SIGNAL_CLD_STOPPED 0x00000010 261 #define SIGNAL_CLD_CONTINUED 0x00000020 262 #define SIGNAL_CLD_MASK (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED) 263 264 #define SIGNAL_UNKILLABLE 0x00000040 /* for init: ignore fatal signals */ 265 266 #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \ 267 SIGNAL_STOP_CONTINUED) 268 269 static inline void signal_set_stop_flags(struct signal_struct *sig, 270 unsigned int flags) 271 { 272 WARN_ON(sig->flags & SIGNAL_GROUP_EXIT); 273 sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags; 274 } 275 276 extern void flush_signals(struct task_struct *); 277 extern void ignore_signals(struct task_struct *); 278 extern void flush_signal_handlers(struct task_struct *, int force_default); 279 extern int dequeue_signal(struct task_struct *task, sigset_t *mask, 280 kernel_siginfo_t *info, enum pid_type *type); 281 282 static inline int kernel_dequeue_signal(void) 283 { 284 struct task_struct *task = current; 285 kernel_siginfo_t __info; 286 enum pid_type __type; 287 int ret; 288 289 spin_lock_irq(&task->sighand->siglock); 290 ret = dequeue_signal(task, &task->blocked, &__info, &__type); 291 spin_unlock_irq(&task->sighand->siglock); 292 293 return ret; 294 } 295 296 static inline void kernel_signal_stop(void) 297 { 298 spin_lock_irq(¤t->sighand->siglock); 299 if (current->jobctl & JOBCTL_STOP_DEQUEUED) { 300 current->jobctl |= JOBCTL_STOPPED; 301 set_special_state(TASK_STOPPED); 302 } 303 spin_unlock_irq(¤t->sighand->siglock); 304 305 schedule(); 306 } 307 308 int force_sig_fault_to_task(int sig, int code, void __user *addr, 309 struct task_struct *t); 310 int force_sig_fault(int sig, int code, void __user *addr); 311 int send_sig_fault(int sig, int code, void __user *addr, struct task_struct *t); 312 313 int force_sig_mceerr(int code, void __user *, short); 314 int send_sig_mceerr(int code, void __user *, short, struct task_struct *); 315 316 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper); 317 int force_sig_pkuerr(void __user *addr, u32 pkey); 318 int send_sig_perf(void __user *addr, u32 type, u64 sig_data); 319 320 int force_sig_ptrace_errno_trap(int errno, void __user *addr); 321 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno); 322 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno, 323 struct task_struct *t); 324 int force_sig_seccomp(int syscall, int reason, bool force_coredump); 325 326 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *); 327 extern void force_sigsegv(int sig); 328 extern int force_sig_info(struct kernel_siginfo *); 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_usb_asyncio(int sig, int errno, sigval_t addr, 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); 338 extern void force_fatal_sig(int); 339 extern void force_exit_sig(int); 340 extern int send_sig(int, struct task_struct *, int); 341 extern int zap_other_threads(struct task_struct *p); 342 extern struct sigqueue *sigqueue_alloc(void); 343 extern void sigqueue_free(struct sigqueue *); 344 extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type); 345 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *); 346 347 static inline void clear_notify_signal(void) 348 { 349 clear_thread_flag(TIF_NOTIFY_SIGNAL); 350 smp_mb__after_atomic(); 351 } 352 353 /* 354 * Returns 'true' if kick_process() is needed to force a transition from 355 * user -> kernel to guarantee expedient run of TWA_SIGNAL based task_work. 356 */ 357 static inline bool __set_notify_signal(struct task_struct *task) 358 { 359 return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) && 360 !wake_up_state(task, TASK_INTERRUPTIBLE); 361 } 362 363 /* 364 * Called to break out of interruptible wait loops, and enter the 365 * exit_to_user_mode_loop(). 366 */ 367 static inline void set_notify_signal(struct task_struct *task) 368 { 369 if (__set_notify_signal(task)) 370 kick_process(task); 371 } 372 373 static inline int restart_syscall(void) 374 { 375 set_tsk_thread_flag(current, TIF_SIGPENDING); 376 return -ERESTARTNOINTR; 377 } 378 379 static inline int task_sigpending(struct task_struct *p) 380 { 381 return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING)); 382 } 383 384 static inline int signal_pending(struct task_struct *p) 385 { 386 /* 387 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same 388 * behavior in terms of ensuring that we break out of wait loops 389 * so that notify signal callbacks can be processed. 390 */ 391 if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL))) 392 return 1; 393 return task_sigpending(p); 394 } 395 396 static inline int __fatal_signal_pending(struct task_struct *p) 397 { 398 return unlikely(sigismember(&p->pending.signal, SIGKILL)); 399 } 400 401 static inline int fatal_signal_pending(struct task_struct *p) 402 { 403 return task_sigpending(p) && __fatal_signal_pending(p); 404 } 405 406 static inline int signal_pending_state(unsigned int state, struct task_struct *p) 407 { 408 if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL))) 409 return 0; 410 if (!signal_pending(p)) 411 return 0; 412 413 return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p); 414 } 415 416 /* 417 * This should only be used in fault handlers to decide whether we 418 * should stop the current fault routine to handle the signals 419 * instead, especially with the case where we've got interrupted with 420 * a VM_FAULT_RETRY. 421 */ 422 static inline bool fault_signal_pending(vm_fault_t fault_flags, 423 struct pt_regs *regs) 424 { 425 return unlikely((fault_flags & VM_FAULT_RETRY) && 426 (fatal_signal_pending(current) || 427 (user_mode(regs) && signal_pending(current)))); 428 } 429 430 /* 431 * Reevaluate whether the task has signals pending delivery. 432 * Wake the task if so. 433 * This is required every time the blocked sigset_t changes. 434 * callers must hold sighand->siglock. 435 */ 436 extern void recalc_sigpending(void); 437 extern void calculate_sigpending(void); 438 439 extern void signal_wake_up_state(struct task_struct *t, unsigned int state); 440 441 static inline void signal_wake_up(struct task_struct *t, bool fatal) 442 { 443 unsigned int state = 0; 444 if (fatal && !(t->jobctl & JOBCTL_PTRACE_FROZEN)) { 445 t->jobctl &= ~(JOBCTL_STOPPED | JOBCTL_TRACED); 446 state = TASK_WAKEKILL | __TASK_TRACED; 447 } 448 signal_wake_up_state(t, state); 449 } 450 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume) 451 { 452 unsigned int state = 0; 453 if (resume) { 454 t->jobctl &= ~JOBCTL_TRACED; 455 state = __TASK_TRACED; 456 } 457 signal_wake_up_state(t, state); 458 } 459 460 void task_join_group_stop(struct task_struct *task); 461 462 #ifdef TIF_RESTORE_SIGMASK 463 /* 464 * Legacy restore_sigmask accessors. These are inefficient on 465 * SMP architectures because they require atomic operations. 466 */ 467 468 /** 469 * set_restore_sigmask() - make sure saved_sigmask processing gets done 470 * 471 * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code 472 * will run before returning to user mode, to process the flag. For 473 * all callers, TIF_SIGPENDING is already set or it's no harm to set 474 * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the 475 * arch code will notice on return to user mode, in case those bits 476 * are scarce. We set TIF_SIGPENDING here to ensure that the arch 477 * signal code always gets run when TIF_RESTORE_SIGMASK is set. 478 */ 479 static inline void set_restore_sigmask(void) 480 { 481 set_thread_flag(TIF_RESTORE_SIGMASK); 482 } 483 484 static inline void clear_tsk_restore_sigmask(struct task_struct *task) 485 { 486 clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK); 487 } 488 489 static inline void clear_restore_sigmask(void) 490 { 491 clear_thread_flag(TIF_RESTORE_SIGMASK); 492 } 493 static inline bool test_tsk_restore_sigmask(struct task_struct *task) 494 { 495 return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK); 496 } 497 static inline bool test_restore_sigmask(void) 498 { 499 return test_thread_flag(TIF_RESTORE_SIGMASK); 500 } 501 static inline bool test_and_clear_restore_sigmask(void) 502 { 503 return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK); 504 } 505 506 #else /* TIF_RESTORE_SIGMASK */ 507 508 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */ 509 static inline void set_restore_sigmask(void) 510 { 511 current->restore_sigmask = true; 512 } 513 static inline void clear_tsk_restore_sigmask(struct task_struct *task) 514 { 515 task->restore_sigmask = false; 516 } 517 static inline void clear_restore_sigmask(void) 518 { 519 current->restore_sigmask = false; 520 } 521 static inline bool test_restore_sigmask(void) 522 { 523 return current->restore_sigmask; 524 } 525 static inline bool test_tsk_restore_sigmask(struct task_struct *task) 526 { 527 return task->restore_sigmask; 528 } 529 static inline bool test_and_clear_restore_sigmask(void) 530 { 531 if (!current->restore_sigmask) 532 return false; 533 current->restore_sigmask = false; 534 return true; 535 } 536 #endif 537 538 static inline void restore_saved_sigmask(void) 539 { 540 if (test_and_clear_restore_sigmask()) 541 __set_current_blocked(¤t->saved_sigmask); 542 } 543 544 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize); 545 546 static inline void restore_saved_sigmask_unless(bool interrupted) 547 { 548 if (interrupted) 549 WARN_ON(!signal_pending(current)); 550 else 551 restore_saved_sigmask(); 552 } 553 554 static inline sigset_t *sigmask_to_save(void) 555 { 556 sigset_t *res = ¤t->blocked; 557 if (unlikely(test_restore_sigmask())) 558 res = ¤t->saved_sigmask; 559 return res; 560 } 561 562 static inline int kill_cad_pid(int sig, int priv) 563 { 564 return kill_pid(cad_pid, sig, priv); 565 } 566 567 /* These can be the second arg to send_sig_info/send_group_sig_info. */ 568 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0) 569 #define SEND_SIG_PRIV ((struct kernel_siginfo *) 1) 570 571 static inline int __on_sig_stack(unsigned long sp) 572 { 573 #ifdef CONFIG_STACK_GROWSUP 574 return sp >= current->sas_ss_sp && 575 sp - current->sas_ss_sp < current->sas_ss_size; 576 #else 577 return sp > current->sas_ss_sp && 578 sp - current->sas_ss_sp <= current->sas_ss_size; 579 #endif 580 } 581 582 /* 583 * True if we are on the alternate signal stack. 584 */ 585 static inline int on_sig_stack(unsigned long sp) 586 { 587 /* 588 * If the signal stack is SS_AUTODISARM then, by construction, we 589 * can't be on the signal stack unless user code deliberately set 590 * SS_AUTODISARM when we were already on it. 591 * 592 * This improves reliability: if user state gets corrupted such that 593 * the stack pointer points very close to the end of the signal stack, 594 * then this check will enable the signal to be handled anyway. 595 */ 596 if (current->sas_ss_flags & SS_AUTODISARM) 597 return 0; 598 599 return __on_sig_stack(sp); 600 } 601 602 static inline int sas_ss_flags(unsigned long sp) 603 { 604 if (!current->sas_ss_size) 605 return SS_DISABLE; 606 607 return on_sig_stack(sp) ? SS_ONSTACK : 0; 608 } 609 610 static inline void sas_ss_reset(struct task_struct *p) 611 { 612 p->sas_ss_sp = 0; 613 p->sas_ss_size = 0; 614 p->sas_ss_flags = SS_DISABLE; 615 } 616 617 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig) 618 { 619 if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp)) 620 #ifdef CONFIG_STACK_GROWSUP 621 return current->sas_ss_sp; 622 #else 623 return current->sas_ss_sp + current->sas_ss_size; 624 #endif 625 return sp; 626 } 627 628 extern void __cleanup_sighand(struct sighand_struct *); 629 extern void flush_itimer_signals(void); 630 631 #define tasklist_empty() \ 632 list_empty(&init_task.tasks) 633 634 #define next_task(p) \ 635 list_entry_rcu((p)->tasks.next, struct task_struct, tasks) 636 637 #define for_each_process(p) \ 638 for (p = &init_task ; (p = next_task(p)) != &init_task ; ) 639 640 extern bool current_is_single_threaded(void); 641 642 /* 643 * Without tasklist/siglock it is only rcu-safe if g can't exit/exec, 644 * otherwise next_thread(t) will never reach g after list_del_rcu(g). 645 */ 646 #define while_each_thread(g, t) \ 647 while ((t = next_thread(t)) != g) 648 649 #define for_other_threads(p, t) \ 650 for (t = p; (t = next_thread(t)) != p; ) 651 652 #define __for_each_thread(signal, t) \ 653 list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node, \ 654 lockdep_is_held(&tasklist_lock)) 655 656 #define for_each_thread(p, t) \ 657 __for_each_thread((p)->signal, t) 658 659 /* Careful: this is a double loop, 'break' won't work as expected. */ 660 #define for_each_process_thread(p, t) \ 661 for_each_process(p) for_each_thread(p, t) 662 663 typedef int (*proc_visitor)(struct task_struct *p, void *data); 664 void walk_process_tree(struct task_struct *top, proc_visitor, void *); 665 666 static inline 667 struct pid *task_pid_type(struct task_struct *task, enum pid_type type) 668 { 669 struct pid *pid; 670 if (type == PIDTYPE_PID) 671 pid = task_pid(task); 672 else 673 pid = task->signal->pids[type]; 674 return pid; 675 } 676 677 static inline struct pid *task_tgid(struct task_struct *task) 678 { 679 return task->signal->pids[PIDTYPE_TGID]; 680 } 681 682 /* 683 * Without tasklist or RCU lock it is not safe to dereference 684 * the result of task_pgrp/task_session even if task == current, 685 * we can race with another thread doing sys_setsid/sys_setpgid. 686 */ 687 static inline struct pid *task_pgrp(struct task_struct *task) 688 { 689 return task->signal->pids[PIDTYPE_PGID]; 690 } 691 692 static inline struct pid *task_session(struct task_struct *task) 693 { 694 return task->signal->pids[PIDTYPE_SID]; 695 } 696 697 static inline int get_nr_threads(struct task_struct *task) 698 { 699 return task->signal->nr_threads; 700 } 701 702 static inline bool thread_group_leader(struct task_struct *p) 703 { 704 return p->exit_signal >= 0; 705 } 706 707 static inline 708 bool same_thread_group(struct task_struct *p1, struct task_struct *p2) 709 { 710 return p1->signal == p2->signal; 711 } 712 713 /* 714 * returns NULL if p is the last thread in the thread group 715 */ 716 static inline struct task_struct *__next_thread(struct task_struct *p) 717 { 718 return list_next_or_null_rcu(&p->signal->thread_head, 719 &p->thread_node, 720 struct task_struct, 721 thread_node); 722 } 723 724 static inline struct task_struct *next_thread(struct task_struct *p) 725 { 726 return __next_thread(p) ?: p->group_leader; 727 } 728 729 static inline int thread_group_empty(struct task_struct *p) 730 { 731 return thread_group_leader(p) && 732 list_is_last(&p->thread_node, &p->signal->thread_head); 733 } 734 735 #define delay_group_leader(p) \ 736 (thread_group_leader(p) && !thread_group_empty(p)) 737 738 extern bool thread_group_exited(struct pid *pid); 739 740 extern struct sighand_struct *__lock_task_sighand(struct task_struct *task, 741 unsigned long *flags); 742 743 static inline struct sighand_struct *lock_task_sighand(struct task_struct *task, 744 unsigned long *flags) 745 { 746 struct sighand_struct *ret; 747 748 ret = __lock_task_sighand(task, flags); 749 (void)__cond_lock(&task->sighand->siglock, ret); 750 return ret; 751 } 752 753 static inline void unlock_task_sighand(struct task_struct *task, 754 unsigned long *flags) 755 { 756 spin_unlock_irqrestore(&task->sighand->siglock, *flags); 757 } 758 759 #ifdef CONFIG_LOCKDEP 760 extern void lockdep_assert_task_sighand_held(struct task_struct *task); 761 #else 762 static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { } 763 #endif 764 765 static inline unsigned long task_rlimit(const struct task_struct *task, 766 unsigned int limit) 767 { 768 return READ_ONCE(task->signal->rlim[limit].rlim_cur); 769 } 770 771 static inline unsigned long task_rlimit_max(const struct task_struct *task, 772 unsigned int limit) 773 { 774 return READ_ONCE(task->signal->rlim[limit].rlim_max); 775 } 776 777 static inline unsigned long rlimit(unsigned int limit) 778 { 779 return task_rlimit(current, limit); 780 } 781 782 static inline unsigned long rlimit_max(unsigned int limit) 783 { 784 return task_rlimit_max(current, limit); 785 } 786 787 #endif /* _LINUX_SCHED_SIGNAL_H */ 788