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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  #include <linux/android_kabi.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  /*
77   * NOTE! "signal_struct" does not have its own
78   * locking, because a shared signal_struct always
79   * implies a shared sighand_struct, so locking
80   * sighand_struct is always a proper superset of
81   * the locking of signal_struct.
82   */
83  struct signal_struct {
84  	refcount_t		sigcnt;
85  	atomic_t		live;
86  	int			nr_threads;
87  	struct list_head	thread_head;
88  
89  	wait_queue_head_t	wait_chldexit;	/* for wait4() */
90  
91  	/* current thread group signal load-balancing target: */
92  	struct task_struct	*curr_target;
93  
94  	/* shared signal handling: */
95  	struct sigpending	shared_pending;
96  
97  	/* For collecting multiprocess signals during fork */
98  	struct hlist_head	multiprocess;
99  
100  	/* thread group exit support */
101  	int			group_exit_code;
102  	/* overloaded:
103  	 * - notify group_exit_task when ->count is equal to notify_count
104  	 * - everyone except group_exit_task is stopped during signal delivery
105  	 *   of fatal signals, group_exit_task processes the signal.
106  	 */
107  	int			notify_count;
108  	struct task_struct	*group_exit_task;
109  
110  	/* thread group stop support, overloads group_exit_code too */
111  	int			group_stop_count;
112  	unsigned int		flags; /* see SIGNAL_* flags below */
113  
114  	/*
115  	 * PR_SET_CHILD_SUBREAPER marks a process, like a service
116  	 * manager, to re-parent orphan (double-forking) child processes
117  	 * to this process instead of 'init'. The service manager is
118  	 * able to receive SIGCHLD signals and is able to investigate
119  	 * the process until it calls wait(). All children of this
120  	 * process will inherit a flag if they should look for a
121  	 * child_subreaper process at exit.
122  	 */
123  	unsigned int		is_child_subreaper:1;
124  	unsigned int		has_child_subreaper:1;
125  
126  #ifdef CONFIG_POSIX_TIMERS
127  
128  	/* POSIX.1b Interval Timers */
129  	int			posix_timer_id;
130  	struct list_head	posix_timers;
131  
132  	/* ITIMER_REAL timer for the process */
133  	struct hrtimer real_timer;
134  	ktime_t it_real_incr;
135  
136  	/*
137  	 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
138  	 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
139  	 * values are defined to 0 and 1 respectively
140  	 */
141  	struct cpu_itimer it[2];
142  
143  	/*
144  	 * Thread group totals for process CPU timers.
145  	 * See thread_group_cputimer(), et al, for details.
146  	 */
147  	struct thread_group_cputimer cputimer;
148  
149  #endif
150  	/* Empty if CONFIG_POSIX_TIMERS=n */
151  	struct posix_cputimers posix_cputimers;
152  
153  	/* PID/PID hash table linkage. */
154  	struct pid *pids[PIDTYPE_MAX];
155  
156  #ifdef CONFIG_NO_HZ_FULL
157  	atomic_t tick_dep_mask;
158  #endif
159  
160  	struct pid *tty_old_pgrp;
161  
162  	/* boolean value for session group leader */
163  	int leader;
164  
165  	struct tty_struct *tty; /* NULL if no tty */
166  
167  #ifdef CONFIG_SCHED_AUTOGROUP
168  	struct autogroup *autogroup;
169  #endif
170  	/*
171  	 * Cumulative resource counters for dead threads in the group,
172  	 * and for reaped dead child processes forked by this group.
173  	 * Live threads maintain their own counters and add to these
174  	 * in __exit_signal, except for the group leader.
175  	 */
176  	seqlock_t stats_lock;
177  	u64 utime, stime, cutime, cstime;
178  	u64 gtime;
179  	u64 cgtime;
180  	struct prev_cputime prev_cputime;
181  	unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
182  	unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
183  	unsigned long inblock, oublock, cinblock, coublock;
184  	unsigned long maxrss, cmaxrss;
185  	struct task_io_accounting ioac;
186  
187  	/*
188  	 * Cumulative ns of schedule CPU time fo dead threads in the
189  	 * group, not including a zombie group leader, (This only differs
190  	 * from jiffies_to_ns(utime + stime) if sched_clock uses something
191  	 * other than jiffies.)
192  	 */
193  	unsigned long long sum_sched_runtime;
194  
195  	/*
196  	 * We don't bother to synchronize most readers of this at all,
197  	 * because there is no reader checking a limit that actually needs
198  	 * to get both rlim_cur and rlim_max atomically, and either one
199  	 * alone is a single word that can safely be read normally.
200  	 * getrlimit/setrlimit use task_lock(current->group_leader) to
201  	 * protect this instead of the siglock, because they really
202  	 * have no need to disable irqs.
203  	 */
204  	struct rlimit rlim[RLIM_NLIMITS];
205  
206  #ifdef CONFIG_BSD_PROCESS_ACCT
207  	struct pacct_struct pacct;	/* per-process accounting information */
208  #endif
209  #ifdef CONFIG_TASKSTATS
210  	struct taskstats *stats;
211  #endif
212  #ifdef CONFIG_AUDIT
213  	unsigned audit_tty;
214  	struct tty_audit_buf *tty_audit_buf;
215  #endif
216  
217  	/*
218  	 * Thread is the potential origin of an oom condition; kill first on
219  	 * oom
220  	 */
221  	bool oom_flag_origin;
222  	short oom_score_adj;		/* OOM kill score adjustment */
223  	short oom_score_adj_min;	/* OOM kill score adjustment min value.
224  					 * Only settable by CAP_SYS_RESOURCE. */
225  	struct mm_struct *oom_mm;	/* recorded mm when the thread group got
226  					 * killed by the oom killer */
227  
228  	struct mutex cred_guard_mutex;	/* guard against foreign influences on
229  					 * credential calculations
230  					 * (notably. ptrace)
231  					 * Deprecated do not use in new code.
232  					 * Use exec_update_lock instead.
233  					 */
234  	struct rw_semaphore exec_update_lock;	/* Held while task_struct is
235  						 * being updated during exec,
236  						 * and may have inconsistent
237  						 * permissions.
238  						 */
239  
240  	ANDROID_KABI_RESERVE(1);
241  	ANDROID_KABI_RESERVE(2);
242  	ANDROID_KABI_RESERVE(3);
243  	ANDROID_KABI_RESERVE(4);
244  } __randomize_layout;
245  
246  /*
247   * Bits in flags field of signal_struct.
248   */
249  #define SIGNAL_STOP_STOPPED	0x00000001 /* job control stop in effect */
250  #define SIGNAL_STOP_CONTINUED	0x00000002 /* SIGCONT since WCONTINUED reap */
251  #define SIGNAL_GROUP_EXIT	0x00000004 /* group exit in progress */
252  #define SIGNAL_GROUP_COREDUMP	0x00000008 /* coredump in progress */
253  /*
254   * Pending notifications to parent.
255   */
256  #define SIGNAL_CLD_STOPPED	0x00000010
257  #define SIGNAL_CLD_CONTINUED	0x00000020
258  #define SIGNAL_CLD_MASK		(SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
259  
260  #define SIGNAL_UNKILLABLE	0x00000040 /* for init: ignore fatal signals */
261  
262  #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
263  			  SIGNAL_STOP_CONTINUED)
264  
signal_set_stop_flags(struct signal_struct * sig,unsigned int flags)265  static inline void signal_set_stop_flags(struct signal_struct *sig,
266  					 unsigned int flags)
267  {
268  	WARN_ON(sig->flags & (SIGNAL_GROUP_EXIT|SIGNAL_GROUP_COREDUMP));
269  	sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
270  }
271  
272  /* If true, all threads except ->group_exit_task have pending SIGKILL */
signal_group_exit(const struct signal_struct * sig)273  static inline int signal_group_exit(const struct signal_struct *sig)
274  {
275  	return	(sig->flags & SIGNAL_GROUP_EXIT) ||
276  		(sig->group_exit_task != NULL);
277  }
278  
279  extern void flush_signals(struct task_struct *);
280  extern void ignore_signals(struct task_struct *);
281  extern void flush_signal_handlers(struct task_struct *, int force_default);
282  extern int dequeue_signal(struct task_struct *task,
283  			  sigset_t *mask, kernel_siginfo_t *info);
284  
kernel_dequeue_signal(void)285  static inline int kernel_dequeue_signal(void)
286  {
287  	struct task_struct *task = current;
288  	kernel_siginfo_t __info;
289  	int ret;
290  
291  	spin_lock_irq(&task->sighand->siglock);
292  	ret = dequeue_signal(task, &task->blocked, &__info);
293  	spin_unlock_irq(&task->sighand->siglock);
294  
295  	return ret;
296  }
297  
kernel_signal_stop(void)298  static inline void kernel_signal_stop(void)
299  {
300  	spin_lock_irq(&current->sighand->siglock);
301  	if (current->jobctl & JOBCTL_STOP_DEQUEUED)
302  		set_special_state(TASK_STOPPED);
303  	spin_unlock_irq(&current->sighand->siglock);
304  
305  	schedule();
306  }
307  #ifdef __ia64__
308  # define ___ARCH_SI_IA64(_a1, _a2, _a3) , _a1, _a2, _a3
309  #else
310  # define ___ARCH_SI_IA64(_a1, _a2, _a3)
311  #endif
312  
313  int force_sig_fault_to_task(int sig, int code, void __user *addr
314  	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
315  	, struct task_struct *t);
316  int force_sig_fault(int sig, int code, void __user *addr
317  	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr));
318  int send_sig_fault(int sig, int code, void __user *addr
319  	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
320  	, struct task_struct *t);
321  
322  int force_sig_mceerr(int code, void __user *, short);
323  int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
324  
325  int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
326  int force_sig_pkuerr(void __user *addr, u32 pkey);
327  int force_sig_perf(void __user *addr, u32 type, u64 sig_data);
328  
329  int force_sig_ptrace_errno_trap(int errno, void __user *addr);
330  int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
331  int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
332  			struct task_struct *t);
333  int force_sig_seccomp(int syscall, int reason, bool force_coredump);
334  
335  extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
336  extern void force_sigsegv(int sig);
337  extern int force_sig_info(struct kernel_siginfo *);
338  extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
339  extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
340  extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
341  				const struct cred *);
342  extern int kill_pgrp(struct pid *pid, int sig, int priv);
343  extern int kill_pid(struct pid *pid, int sig, int priv);
344  extern __must_check bool do_notify_parent(struct task_struct *, int);
345  extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
346  extern void force_sig(int);
347  extern void force_fatal_sig(int);
348  extern void force_exit_sig(int);
349  extern int send_sig(int, struct task_struct *, int);
350  extern int zap_other_threads(struct task_struct *p);
351  extern struct sigqueue *sigqueue_alloc(void);
352  extern void sigqueue_free(struct sigqueue *);
353  extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
354  extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
355  
restart_syscall(void)356  static inline int restart_syscall(void)
357  {
358  	set_tsk_thread_flag(current, TIF_SIGPENDING);
359  	return -ERESTARTNOINTR;
360  }
361  
task_sigpending(struct task_struct * p)362  static inline int task_sigpending(struct task_struct *p)
363  {
364  	return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
365  }
366  
signal_pending(struct task_struct * p)367  static inline int signal_pending(struct task_struct *p)
368  {
369  	/*
370  	 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
371  	 * behavior in terms of ensuring that we break out of wait loops
372  	 * so that notify signal callbacks can be processed.
373  	 */
374  	if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
375  		return 1;
376  	return task_sigpending(p);
377  }
378  
__fatal_signal_pending(struct task_struct * p)379  static inline int __fatal_signal_pending(struct task_struct *p)
380  {
381  	return unlikely(sigismember(&p->pending.signal, SIGKILL));
382  }
383  
fatal_signal_pending(struct task_struct * p)384  static inline int fatal_signal_pending(struct task_struct *p)
385  {
386  	return task_sigpending(p) && __fatal_signal_pending(p);
387  }
388  
signal_pending_state(unsigned int state,struct task_struct * p)389  static inline int signal_pending_state(unsigned int state, struct task_struct *p)
390  {
391  	if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
392  		return 0;
393  	if (!signal_pending(p))
394  		return 0;
395  
396  	return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
397  }
398  
399  /*
400   * This should only be used in fault handlers to decide whether we
401   * should stop the current fault routine to handle the signals
402   * instead, especially with the case where we've got interrupted with
403   * a VM_FAULT_RETRY.
404   */
fault_signal_pending(vm_fault_t fault_flags,struct pt_regs * regs)405  static inline bool fault_signal_pending(vm_fault_t fault_flags,
406  					struct pt_regs *regs)
407  {
408  	return unlikely((fault_flags & VM_FAULT_RETRY) &&
409  			(fatal_signal_pending(current) ||
410  			 (user_mode(regs) && signal_pending(current))));
411  }
412  
413  /*
414   * Reevaluate whether the task has signals pending delivery.
415   * Wake the task if so.
416   * This is required every time the blocked sigset_t changes.
417   * callers must hold sighand->siglock.
418   */
419  extern void recalc_sigpending_and_wake(struct task_struct *t);
420  extern void recalc_sigpending(void);
421  extern void calculate_sigpending(void);
422  
423  extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
424  
signal_wake_up(struct task_struct * t,bool resume)425  static inline void signal_wake_up(struct task_struct *t, bool resume)
426  {
427  	signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
428  }
ptrace_signal_wake_up(struct task_struct * t,bool resume)429  static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
430  {
431  	signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
432  }
433  
434  void task_join_group_stop(struct task_struct *task);
435  
436  #ifdef TIF_RESTORE_SIGMASK
437  /*
438   * Legacy restore_sigmask accessors.  These are inefficient on
439   * SMP architectures because they require atomic operations.
440   */
441  
442  /**
443   * set_restore_sigmask() - make sure saved_sigmask processing gets done
444   *
445   * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
446   * will run before returning to user mode, to process the flag.  For
447   * all callers, TIF_SIGPENDING is already set or it's no harm to set
448   * it.  TIF_RESTORE_SIGMASK need not be in the set of bits that the
449   * arch code will notice on return to user mode, in case those bits
450   * are scarce.  We set TIF_SIGPENDING here to ensure that the arch
451   * signal code always gets run when TIF_RESTORE_SIGMASK is set.
452   */
set_restore_sigmask(void)453  static inline void set_restore_sigmask(void)
454  {
455  	set_thread_flag(TIF_RESTORE_SIGMASK);
456  }
457  
clear_tsk_restore_sigmask(struct task_struct * task)458  static inline void clear_tsk_restore_sigmask(struct task_struct *task)
459  {
460  	clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
461  }
462  
clear_restore_sigmask(void)463  static inline void clear_restore_sigmask(void)
464  {
465  	clear_thread_flag(TIF_RESTORE_SIGMASK);
466  }
test_tsk_restore_sigmask(struct task_struct * task)467  static inline bool test_tsk_restore_sigmask(struct task_struct *task)
468  {
469  	return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
470  }
test_restore_sigmask(void)471  static inline bool test_restore_sigmask(void)
472  {
473  	return test_thread_flag(TIF_RESTORE_SIGMASK);
474  }
test_and_clear_restore_sigmask(void)475  static inline bool test_and_clear_restore_sigmask(void)
476  {
477  	return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
478  }
479  
480  #else	/* TIF_RESTORE_SIGMASK */
481  
482  /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
set_restore_sigmask(void)483  static inline void set_restore_sigmask(void)
484  {
485  	current->restore_sigmask = true;
486  }
clear_tsk_restore_sigmask(struct task_struct * task)487  static inline void clear_tsk_restore_sigmask(struct task_struct *task)
488  {
489  	task->restore_sigmask = false;
490  }
clear_restore_sigmask(void)491  static inline void clear_restore_sigmask(void)
492  {
493  	current->restore_sigmask = false;
494  }
test_restore_sigmask(void)495  static inline bool test_restore_sigmask(void)
496  {
497  	return current->restore_sigmask;
498  }
test_tsk_restore_sigmask(struct task_struct * task)499  static inline bool test_tsk_restore_sigmask(struct task_struct *task)
500  {
501  	return task->restore_sigmask;
502  }
test_and_clear_restore_sigmask(void)503  static inline bool test_and_clear_restore_sigmask(void)
504  {
505  	if (!current->restore_sigmask)
506  		return false;
507  	current->restore_sigmask = false;
508  	return true;
509  }
510  #endif
511  
restore_saved_sigmask(void)512  static inline void restore_saved_sigmask(void)
513  {
514  	if (test_and_clear_restore_sigmask())
515  		__set_current_blocked(&current->saved_sigmask);
516  }
517  
518  extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
519  
restore_saved_sigmask_unless(bool interrupted)520  static inline void restore_saved_sigmask_unless(bool interrupted)
521  {
522  	if (interrupted)
523  		WARN_ON(!signal_pending(current));
524  	else
525  		restore_saved_sigmask();
526  }
527  
sigmask_to_save(void)528  static inline sigset_t *sigmask_to_save(void)
529  {
530  	sigset_t *res = &current->blocked;
531  	if (unlikely(test_restore_sigmask()))
532  		res = &current->saved_sigmask;
533  	return res;
534  }
535  
kill_cad_pid(int sig,int priv)536  static inline int kill_cad_pid(int sig, int priv)
537  {
538  	return kill_pid(cad_pid, sig, priv);
539  }
540  
541  /* These can be the second arg to send_sig_info/send_group_sig_info.  */
542  #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
543  #define SEND_SIG_PRIV	((struct kernel_siginfo *) 1)
544  
__on_sig_stack(unsigned long sp)545  static inline int __on_sig_stack(unsigned long sp)
546  {
547  #ifdef CONFIG_STACK_GROWSUP
548  	return sp >= current->sas_ss_sp &&
549  		sp - current->sas_ss_sp < current->sas_ss_size;
550  #else
551  	return sp > current->sas_ss_sp &&
552  		sp - current->sas_ss_sp <= current->sas_ss_size;
553  #endif
554  }
555  
556  /*
557   * True if we are on the alternate signal stack.
558   */
on_sig_stack(unsigned long sp)559  static inline int on_sig_stack(unsigned long sp)
560  {
561  	/*
562  	 * If the signal stack is SS_AUTODISARM then, by construction, we
563  	 * can't be on the signal stack unless user code deliberately set
564  	 * SS_AUTODISARM when we were already on it.
565  	 *
566  	 * This improves reliability: if user state gets corrupted such that
567  	 * the stack pointer points very close to the end of the signal stack,
568  	 * then this check will enable the signal to be handled anyway.
569  	 */
570  	if (current->sas_ss_flags & SS_AUTODISARM)
571  		return 0;
572  
573  	return __on_sig_stack(sp);
574  }
575  
sas_ss_flags(unsigned long sp)576  static inline int sas_ss_flags(unsigned long sp)
577  {
578  	if (!current->sas_ss_size)
579  		return SS_DISABLE;
580  
581  	return on_sig_stack(sp) ? SS_ONSTACK : 0;
582  }
583  
sas_ss_reset(struct task_struct * p)584  static inline void sas_ss_reset(struct task_struct *p)
585  {
586  	p->sas_ss_sp = 0;
587  	p->sas_ss_size = 0;
588  	p->sas_ss_flags = SS_DISABLE;
589  }
590  
sigsp(unsigned long sp,struct ksignal * ksig)591  static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
592  {
593  	if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
594  #ifdef CONFIG_STACK_GROWSUP
595  		return current->sas_ss_sp;
596  #else
597  		return current->sas_ss_sp + current->sas_ss_size;
598  #endif
599  	return sp;
600  }
601  
602  extern void __cleanup_sighand(struct sighand_struct *);
603  extern void flush_itimer_signals(void);
604  
605  #define tasklist_empty() \
606  	list_empty(&init_task.tasks)
607  
608  #define next_task(p) \
609  	list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
610  
611  #define for_each_process(p) \
612  	for (p = &init_task ; (p = next_task(p)) != &init_task ; )
613  
614  extern bool current_is_single_threaded(void);
615  
616  /*
617   * Careful: do_each_thread/while_each_thread is a double loop so
618   *          'break' will not work as expected - use goto instead.
619   */
620  #define do_each_thread(g, t) \
621  	for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
622  
623  #define while_each_thread(g, t) \
624  	while ((t = next_thread(t)) != g)
625  
626  #define __for_each_thread(signal, t)	\
627  	list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)
628  
629  #define for_each_thread(p, t)		\
630  	__for_each_thread((p)->signal, t)
631  
632  /* Careful: this is a double loop, 'break' won't work as expected. */
633  #define for_each_process_thread(p, t)	\
634  	for_each_process(p) for_each_thread(p, t)
635  
636  typedef int (*proc_visitor)(struct task_struct *p, void *data);
637  void walk_process_tree(struct task_struct *top, proc_visitor, void *);
638  
639  static inline
task_pid_type(struct task_struct * task,enum pid_type type)640  struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
641  {
642  	struct pid *pid;
643  	if (type == PIDTYPE_PID)
644  		pid = task_pid(task);
645  	else
646  		pid = task->signal->pids[type];
647  	return pid;
648  }
649  
task_tgid(struct task_struct * task)650  static inline struct pid *task_tgid(struct task_struct *task)
651  {
652  	return task->signal->pids[PIDTYPE_TGID];
653  }
654  
655  /*
656   * Without tasklist or RCU lock it is not safe to dereference
657   * the result of task_pgrp/task_session even if task == current,
658   * we can race with another thread doing sys_setsid/sys_setpgid.
659   */
task_pgrp(struct task_struct * task)660  static inline struct pid *task_pgrp(struct task_struct *task)
661  {
662  	return task->signal->pids[PIDTYPE_PGID];
663  }
664  
task_session(struct task_struct * task)665  static inline struct pid *task_session(struct task_struct *task)
666  {
667  	return task->signal->pids[PIDTYPE_SID];
668  }
669  
get_nr_threads(struct task_struct * task)670  static inline int get_nr_threads(struct task_struct *task)
671  {
672  	return task->signal->nr_threads;
673  }
674  
thread_group_leader(struct task_struct * p)675  static inline bool thread_group_leader(struct task_struct *p)
676  {
677  	return p->exit_signal >= 0;
678  }
679  
680  static inline
same_thread_group(struct task_struct * p1,struct task_struct * p2)681  bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
682  {
683  	return p1->signal == p2->signal;
684  }
685  
next_thread(const struct task_struct * p)686  static inline struct task_struct *next_thread(const struct task_struct *p)
687  {
688  	return list_entry_rcu(p->thread_group.next,
689  			      struct task_struct, thread_group);
690  }
691  
thread_group_empty(struct task_struct * p)692  static inline int thread_group_empty(struct task_struct *p)
693  {
694  	return list_empty(&p->thread_group);
695  }
696  
697  #define delay_group_leader(p) \
698  		(thread_group_leader(p) && !thread_group_empty(p))
699  
700  extern bool thread_group_exited(struct pid *pid);
701  
702  extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
703  							unsigned long *flags);
704  
lock_task_sighand(struct task_struct * task,unsigned long * flags)705  static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
706  						       unsigned long *flags)
707  {
708  	struct sighand_struct *ret;
709  
710  	ret = __lock_task_sighand(task, flags);
711  	(void)__cond_lock(&task->sighand->siglock, ret);
712  	return ret;
713  }
714  
unlock_task_sighand(struct task_struct * task,unsigned long * flags)715  static inline void unlock_task_sighand(struct task_struct *task,
716  						unsigned long *flags)
717  {
718  	spin_unlock_irqrestore(&task->sighand->siglock, *flags);
719  }
720  
721  #ifdef CONFIG_LOCKDEP
722  extern void lockdep_assert_task_sighand_held(struct task_struct *task);
723  #else
lockdep_assert_task_sighand_held(struct task_struct * task)724  static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { }
725  #endif
726  
task_rlimit(const struct task_struct * task,unsigned int limit)727  static inline unsigned long task_rlimit(const struct task_struct *task,
728  		unsigned int limit)
729  {
730  	return READ_ONCE(task->signal->rlim[limit].rlim_cur);
731  }
732  
task_rlimit_max(const struct task_struct * task,unsigned int limit)733  static inline unsigned long task_rlimit_max(const struct task_struct *task,
734  		unsigned int limit)
735  {
736  	return READ_ONCE(task->signal->rlim[limit].rlim_max);
737  }
738  
rlimit(unsigned int limit)739  static inline unsigned long rlimit(unsigned int limit)
740  {
741  	return task_rlimit(current, limit);
742  }
743  
rlimit_max(unsigned int limit)744  static inline unsigned long rlimit_max(unsigned int limit)
745  {
746  	return task_rlimit_max(current, limit);
747  }
748  
749  #endif /* _LINUX_SCHED_SIGNAL_H */
750