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 timer_create_restore_ids:1; 140 atomic_t next_posix_timer_id; 141 struct hlist_head posix_timers; 142 struct hlist_head ignored_posix_timers; 143 144 /* ITIMER_REAL timer for the process */ 145 struct hrtimer real_timer; 146 ktime_t it_real_incr; 147 148 /* 149 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use 150 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these 151 * values are defined to 0 and 1 respectively 152 */ 153 struct cpu_itimer it[2]; 154 155 /* 156 * Thread group totals for process CPU timers. 157 * See thread_group_cputimer(), et al, for details. 158 */ 159 struct thread_group_cputimer cputimer; 160 161 #endif 162 /* Empty if CONFIG_POSIX_TIMERS=n */ 163 struct posix_cputimers posix_cputimers; 164 165 /* PID/PID hash table linkage. */ 166 struct pid *pids[PIDTYPE_MAX]; 167 168 #ifdef CONFIG_NO_HZ_FULL 169 atomic_t tick_dep_mask; 170 #endif 171 172 struct pid *tty_old_pgrp; 173 174 /* boolean value for session group leader */ 175 int leader; 176 177 struct tty_struct *tty; /* NULL if no tty */ 178 179 #ifdef CONFIG_SCHED_AUTOGROUP 180 struct autogroup *autogroup; 181 #endif 182 /* 183 * Cumulative resource counters for dead threads in the group, 184 * and for reaped dead child processes forked by this group. 185 * Live threads maintain their own counters and add to these 186 * in __exit_signal, except for the group leader. 187 */ 188 seqlock_t stats_lock; 189 u64 utime, stime, cutime, cstime; 190 u64 gtime; 191 u64 cgtime; 192 struct prev_cputime prev_cputime; 193 unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw; 194 unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt; 195 unsigned long inblock, oublock, cinblock, coublock; 196 unsigned long maxrss, cmaxrss; 197 struct task_io_accounting ioac; 198 199 /* 200 * Cumulative ns of schedule CPU time fo dead threads in the 201 * group, not including a zombie group leader, (This only differs 202 * from jiffies_to_ns(utime + stime) if sched_clock uses something 203 * other than jiffies.) 204 */ 205 unsigned long long sum_sched_runtime; 206 207 /* 208 * We don't bother to synchronize most readers of this at all, 209 * because there is no reader checking a limit that actually needs 210 * to get both rlim_cur and rlim_max atomically, and either one 211 * alone is a single word that can safely be read normally. 212 * getrlimit/setrlimit use task_lock(current->group_leader) to 213 * protect this instead of the siglock, because they really 214 * have no need to disable irqs. 215 */ 216 struct rlimit rlim[RLIM_NLIMITS]; 217 218 #ifdef CONFIG_BSD_PROCESS_ACCT 219 struct pacct_struct pacct; /* per-process accounting information */ 220 #endif 221 #ifdef CONFIG_TASKSTATS 222 struct taskstats *stats; 223 #endif 224 #ifdef CONFIG_AUDIT 225 unsigned audit_tty; 226 struct tty_audit_buf *tty_audit_buf; 227 #endif 228 229 #ifdef CONFIG_CGROUPS 230 struct rw_semaphore cgroup_threadgroup_rwsem; 231 #endif 232 233 /* 234 * Thread is the potential origin of an oom condition; kill first on 235 * oom 236 */ 237 bool oom_flag_origin; 238 short oom_score_adj; /* OOM kill score adjustment */ 239 short oom_score_adj_min; /* OOM kill score adjustment min value. 240 * Only settable by CAP_SYS_RESOURCE. */ 241 struct mm_struct *oom_mm; /* recorded mm when the thread group got 242 * killed by the oom killer */ 243 244 struct mutex cred_guard_mutex; /* guard against foreign influences on 245 * credential calculations 246 * (notably. ptrace) 247 * Deprecated do not use in new code. 248 * Use exec_update_lock instead. 249 */ 250 struct rw_semaphore exec_update_lock; /* Held while task_struct is 251 * being updated during exec, 252 * and may have inconsistent 253 * permissions. 254 */ 255 } __randomize_layout; 256 257 /* 258 * Bits in flags field of signal_struct. 259 */ 260 #define SIGNAL_STOP_STOPPED 0x00000001 /* job control stop in effect */ 261 #define SIGNAL_STOP_CONTINUED 0x00000002 /* SIGCONT since WCONTINUED reap */ 262 #define SIGNAL_GROUP_EXIT 0x00000004 /* group exit in progress */ 263 /* 264 * Pending notifications to parent. 265 */ 266 #define SIGNAL_CLD_STOPPED 0x00000010 267 #define SIGNAL_CLD_CONTINUED 0x00000020 268 #define SIGNAL_CLD_MASK (SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED) 269 270 #define SIGNAL_UNKILLABLE 0x00000040 /* for init: ignore fatal signals */ 271 272 #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \ 273 SIGNAL_STOP_CONTINUED) 274 275 static inline void signal_set_stop_flags(struct signal_struct *sig, 276 unsigned int flags) 277 { 278 WARN_ON(sig->flags & SIGNAL_GROUP_EXIT); 279 sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags; 280 } 281 282 extern void flush_signals(struct task_struct *); 283 extern void ignore_signals(struct task_struct *); 284 extern void flush_signal_handlers(struct task_struct *, int force_default); 285 extern int dequeue_signal(sigset_t *mask, kernel_siginfo_t *info, enum pid_type *type); 286 287 static inline int kernel_dequeue_signal(void) 288 { 289 struct task_struct *task = current; 290 kernel_siginfo_t __info; 291 enum pid_type __type; 292 int ret; 293 294 spin_lock_irq(&task->sighand->siglock); 295 ret = dequeue_signal(&task->blocked, &__info, &__type); 296 spin_unlock_irq(&task->sighand->siglock); 297 298 return ret; 299 } 300 301 static inline void kernel_signal_stop(void) 302 { 303 spin_lock_irq(¤t->sighand->siglock); 304 if (current->jobctl & JOBCTL_STOP_DEQUEUED) { 305 current->jobctl |= JOBCTL_STOPPED; 306 set_special_state(TASK_STOPPED); 307 } 308 spin_unlock_irq(¤t->sighand->siglock); 309 310 schedule(); 311 } 312 313 int force_sig_fault_to_task(int sig, int code, void __user *addr, 314 struct task_struct *t); 315 int force_sig_fault(int sig, int code, void __user *addr); 316 int send_sig_fault(int sig, int code, void __user *addr, struct task_struct *t); 317 318 int force_sig_mceerr(int code, void __user *, short); 319 int send_sig_mceerr(int code, void __user *, short, struct task_struct *); 320 321 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper); 322 int force_sig_pkuerr(void __user *addr, u32 pkey); 323 int send_sig_perf(void __user *addr, u32 type, u64 sig_data); 324 325 int force_sig_ptrace_errno_trap(int errno, void __user *addr); 326 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno); 327 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno, 328 struct task_struct *t); 329 int force_sig_seccomp(int syscall, int reason, bool force_coredump); 330 331 extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *); 332 extern void force_sigsegv(int sig); 333 extern int force_sig_info(struct kernel_siginfo *); 334 extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp); 335 extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid); 336 extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *, 337 const struct cred *); 338 extern int kill_pgrp(struct pid *pid, int sig, int priv); 339 extern int kill_pid(struct pid *pid, int sig, int priv); 340 extern __must_check bool do_notify_parent(struct task_struct *, int); 341 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent); 342 extern void force_sig(int); 343 extern void force_fatal_sig(int); 344 extern void force_exit_sig(int); 345 extern int send_sig(int, struct task_struct *, int); 346 extern int zap_other_threads(struct task_struct *p); 347 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *); 348 349 static inline void clear_notify_signal(void) 350 { 351 clear_thread_flag(TIF_NOTIFY_SIGNAL); 352 smp_mb__after_atomic(); 353 } 354 355 /* 356 * Returns 'true' if kick_process() is needed to force a transition from 357 * user -> kernel to guarantee expedient run of TWA_SIGNAL based task_work. 358 */ 359 static inline bool __set_notify_signal(struct task_struct *task) 360 { 361 return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) && 362 !wake_up_state(task, TASK_INTERRUPTIBLE); 363 } 364 365 /* 366 * Called to break out of interruptible wait loops, and enter the 367 * exit_to_user_mode_loop(). 368 */ 369 static inline void set_notify_signal(struct task_struct *task) 370 { 371 if (__set_notify_signal(task)) 372 kick_process(task); 373 } 374 375 static inline int restart_syscall(void) 376 { 377 set_tsk_thread_flag(current, TIF_SIGPENDING); 378 return -ERESTARTNOINTR; 379 } 380 381 static inline int task_sigpending(struct task_struct *p) 382 { 383 return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING)); 384 } 385 386 static inline int signal_pending(struct task_struct *p) 387 { 388 /* 389 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same 390 * behavior in terms of ensuring that we break out of wait loops 391 * so that notify signal callbacks can be processed. 392 */ 393 if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL))) 394 return 1; 395 return task_sigpending(p); 396 } 397 398 static inline int __fatal_signal_pending(struct task_struct *p) 399 { 400 return unlikely(sigismember(&p->pending.signal, SIGKILL)); 401 } 402 403 static inline int fatal_signal_pending(struct task_struct *p) 404 { 405 return task_sigpending(p) && __fatal_signal_pending(p); 406 } 407 408 static inline int signal_pending_state(unsigned int state, struct task_struct *p) 409 { 410 if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL))) 411 return 0; 412 if (!signal_pending(p)) 413 return 0; 414 415 return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p); 416 } 417 418 /* 419 * This should only be used in fault handlers to decide whether we 420 * should stop the current fault routine to handle the signals 421 * instead, especially with the case where we've got interrupted with 422 * a VM_FAULT_RETRY. 423 */ 424 static inline bool fault_signal_pending(vm_fault_t fault_flags, 425 struct pt_regs *regs) 426 { 427 return unlikely((fault_flags & VM_FAULT_RETRY) && 428 (fatal_signal_pending(current) || 429 (user_mode(regs) && signal_pending(current)))); 430 } 431 432 /* 433 * Reevaluate whether the task has signals pending delivery. 434 * Wake the task if so. 435 * This is required every time the blocked sigset_t changes. 436 * callers must hold sighand->siglock. 437 */ 438 extern void recalc_sigpending(void); 439 extern void calculate_sigpending(void); 440 441 extern void signal_wake_up_state(struct task_struct *t, unsigned int state); 442 443 static inline void signal_wake_up(struct task_struct *t, bool fatal) 444 { 445 unsigned int state = 0; 446 if (fatal && !(t->jobctl & JOBCTL_PTRACE_FROZEN)) { 447 t->jobctl &= ~(JOBCTL_STOPPED | JOBCTL_TRACED); 448 state = TASK_WAKEKILL | __TASK_TRACED; 449 } 450 signal_wake_up_state(t, state); 451 } 452 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume) 453 { 454 unsigned int state = 0; 455 if (resume) { 456 t->jobctl &= ~JOBCTL_TRACED; 457 state = __TASK_TRACED; 458 } 459 signal_wake_up_state(t, state); 460 } 461 462 void task_join_group_stop(struct task_struct *task); 463 464 #ifdef TIF_RESTORE_SIGMASK 465 /* 466 * Legacy restore_sigmask accessors. These are inefficient on 467 * SMP architectures because they require atomic operations. 468 */ 469 470 /** 471 * set_restore_sigmask() - make sure saved_sigmask processing gets done 472 * 473 * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code 474 * will run before returning to user mode, to process the flag. For 475 * all callers, TIF_SIGPENDING is already set or it's no harm to set 476 * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the 477 * arch code will notice on return to user mode, in case those bits 478 * are scarce. We set TIF_SIGPENDING here to ensure that the arch 479 * signal code always gets run when TIF_RESTORE_SIGMASK is set. 480 */ 481 static inline void set_restore_sigmask(void) 482 { 483 set_thread_flag(TIF_RESTORE_SIGMASK); 484 } 485 486 static inline void clear_tsk_restore_sigmask(struct task_struct *task) 487 { 488 clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK); 489 } 490 491 static inline void clear_restore_sigmask(void) 492 { 493 clear_thread_flag(TIF_RESTORE_SIGMASK); 494 } 495 static inline bool test_tsk_restore_sigmask(struct task_struct *task) 496 { 497 return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK); 498 } 499 static inline bool test_restore_sigmask(void) 500 { 501 return test_thread_flag(TIF_RESTORE_SIGMASK); 502 } 503 static inline bool test_and_clear_restore_sigmask(void) 504 { 505 return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK); 506 } 507 508 #else /* TIF_RESTORE_SIGMASK */ 509 510 /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */ 511 static inline void set_restore_sigmask(void) 512 { 513 current->restore_sigmask = true; 514 } 515 static inline void clear_tsk_restore_sigmask(struct task_struct *task) 516 { 517 task->restore_sigmask = false; 518 } 519 static inline void clear_restore_sigmask(void) 520 { 521 current->restore_sigmask = false; 522 } 523 static inline bool test_restore_sigmask(void) 524 { 525 return current->restore_sigmask; 526 } 527 static inline bool test_tsk_restore_sigmask(struct task_struct *task) 528 { 529 return task->restore_sigmask; 530 } 531 static inline bool test_and_clear_restore_sigmask(void) 532 { 533 if (!current->restore_sigmask) 534 return false; 535 current->restore_sigmask = false; 536 return true; 537 } 538 #endif 539 540 static inline void restore_saved_sigmask(void) 541 { 542 if (test_and_clear_restore_sigmask()) 543 __set_current_blocked(¤t->saved_sigmask); 544 } 545 546 extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize); 547 548 static inline void restore_saved_sigmask_unless(bool interrupted) 549 { 550 if (interrupted) 551 WARN_ON(!signal_pending(current)); 552 else 553 restore_saved_sigmask(); 554 } 555 556 static inline sigset_t *sigmask_to_save(void) 557 { 558 sigset_t *res = ¤t->blocked; 559 if (unlikely(test_restore_sigmask())) 560 res = ¤t->saved_sigmask; 561 return res; 562 } 563 564 static inline int kill_cad_pid(int sig, int priv) 565 { 566 return kill_pid(cad_pid, sig, priv); 567 } 568 569 /* These can be the second arg to send_sig_info/send_group_sig_info. */ 570 #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0) 571 #define SEND_SIG_PRIV ((struct kernel_siginfo *) 1) 572 573 static inline int __on_sig_stack(unsigned long sp) 574 { 575 #ifdef CONFIG_STACK_GROWSUP 576 return sp >= current->sas_ss_sp && 577 sp - current->sas_ss_sp < current->sas_ss_size; 578 #else 579 return sp > current->sas_ss_sp && 580 sp - current->sas_ss_sp <= current->sas_ss_size; 581 #endif 582 } 583 584 /* 585 * True if we are on the alternate signal stack. 586 */ 587 static inline int on_sig_stack(unsigned long sp) 588 { 589 /* 590 * If the signal stack is SS_AUTODISARM then, by construction, we 591 * can't be on the signal stack unless user code deliberately set 592 * SS_AUTODISARM when we were already on it. 593 * 594 * This improves reliability: if user state gets corrupted such that 595 * the stack pointer points very close to the end of the signal stack, 596 * then this check will enable the signal to be handled anyway. 597 */ 598 if (current->sas_ss_flags & SS_AUTODISARM) 599 return 0; 600 601 return __on_sig_stack(sp); 602 } 603 604 static inline int sas_ss_flags(unsigned long sp) 605 { 606 if (!current->sas_ss_size) 607 return SS_DISABLE; 608 609 return on_sig_stack(sp) ? SS_ONSTACK : 0; 610 } 611 612 static inline void sas_ss_reset(struct task_struct *p) 613 { 614 p->sas_ss_sp = 0; 615 p->sas_ss_size = 0; 616 p->sas_ss_flags = SS_DISABLE; 617 } 618 619 static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig) 620 { 621 if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp)) 622 #ifdef CONFIG_STACK_GROWSUP 623 return current->sas_ss_sp; 624 #else 625 return current->sas_ss_sp + current->sas_ss_size; 626 #endif 627 return sp; 628 } 629 630 extern void __cleanup_sighand(struct sighand_struct *); 631 extern void flush_itimer_signals(void); 632 633 #define tasklist_empty() \ 634 list_empty(&init_task.tasks) 635 636 #define next_task(p) \ 637 list_entry_rcu((p)->tasks.next, struct task_struct, tasks) 638 639 #define for_each_process(p) \ 640 for (p = &init_task ; (p = next_task(p)) != &init_task ; ) 641 642 extern bool current_is_single_threaded(void); 643 644 /* 645 * Without tasklist/siglock it is only rcu-safe if g can't exit/exec, 646 * otherwise next_thread(t) will never reach g after list_del_rcu(g). 647 */ 648 #define while_each_thread(g, t) \ 649 while ((t = next_thread(t)) != g) 650 651 #define for_other_threads(p, t) \ 652 for (t = p; (t = next_thread(t)) != p; ) 653 654 #define __for_each_thread(signal, t) \ 655 list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node, \ 656 lockdep_is_held(&tasklist_lock)) 657 658 #define for_each_thread(p, t) \ 659 __for_each_thread((p)->signal, t) 660 661 /* Careful: this is a double loop, 'break' won't work as expected. */ 662 #define for_each_process_thread(p, t) \ 663 for_each_process(p) for_each_thread(p, t) 664 665 typedef int (*proc_visitor)(struct task_struct *p, void *data); 666 void walk_process_tree(struct task_struct *top, proc_visitor, void *); 667 668 static inline 669 struct pid *task_pid_type(struct task_struct *task, enum pid_type type) 670 { 671 struct pid *pid; 672 if (type == PIDTYPE_PID) 673 pid = task_pid(task); 674 else 675 pid = task->signal->pids[type]; 676 return pid; 677 } 678 679 static inline struct pid *task_tgid(struct task_struct *task) 680 { 681 return task->signal->pids[PIDTYPE_TGID]; 682 } 683 684 /* 685 * Without tasklist or RCU lock it is not safe to dereference 686 * the result of task_pgrp/task_session even if task == current, 687 * we can race with another thread doing sys_setsid/sys_setpgid. 688 */ 689 static inline struct pid *task_pgrp(struct task_struct *task) 690 { 691 return task->signal->pids[PIDTYPE_PGID]; 692 } 693 694 static inline struct pid *task_session(struct task_struct *task) 695 { 696 return task->signal->pids[PIDTYPE_SID]; 697 } 698 699 static inline int get_nr_threads(struct task_struct *task) 700 { 701 return task->signal->nr_threads; 702 } 703 704 static inline bool thread_group_leader(struct task_struct *p) 705 { 706 return p->exit_signal >= 0; 707 } 708 709 static inline 710 bool same_thread_group(struct task_struct *p1, struct task_struct *p2) 711 { 712 return p1->signal == p2->signal; 713 } 714 715 /* 716 * returns NULL if p is the last thread in the thread group 717 */ 718 static inline struct task_struct *__next_thread(struct task_struct *p) 719 { 720 return list_next_or_null_rcu(&p->signal->thread_head, 721 &p->thread_node, 722 struct task_struct, 723 thread_node); 724 } 725 726 static inline struct task_struct *next_thread(struct task_struct *p) 727 { 728 return __next_thread(p) ?: p->group_leader; 729 } 730 731 static inline int thread_group_empty(struct task_struct *p) 732 { 733 return thread_group_leader(p) && 734 list_is_last(&p->thread_node, &p->signal->thread_head); 735 } 736 737 #define delay_group_leader(p) \ 738 (thread_group_leader(p) && !thread_group_empty(p)) 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