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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  
14  /*
15   * Types defining task->signal and task->sighand and APIs using them:
16   */
17  
18  struct sighand_struct {
19  	spinlock_t		siglock;
20  	refcount_t		count;
21  	wait_queue_head_t	signalfd_wqh;
22  	struct k_sigaction	action[_NSIG];
23  };
24  
25  /*
26   * Per-process accounting stats:
27   */
28  struct pacct_struct {
29  	int			ac_flag;
30  	long			ac_exitcode;
31  	unsigned long		ac_mem;
32  	u64			ac_utime, ac_stime;
33  	unsigned long		ac_minflt, ac_majflt;
34  };
35  
36  struct cpu_itimer {
37  	u64 expires;
38  	u64 incr;
39  };
40  
41  /*
42   * This is the atomic variant of task_cputime, which can be used for
43   * storing and updating task_cputime statistics without locking.
44   */
45  struct task_cputime_atomic {
46  	atomic64_t utime;
47  	atomic64_t stime;
48  	atomic64_t sum_exec_runtime;
49  };
50  
51  #define INIT_CPUTIME_ATOMIC \
52  	(struct task_cputime_atomic) {				\
53  		.utime = ATOMIC64_INIT(0),			\
54  		.stime = ATOMIC64_INIT(0),			\
55  		.sum_exec_runtime = ATOMIC64_INIT(0),		\
56  	}
57  /**
58   * struct thread_group_cputimer - thread group interval timer counts
59   * @cputime_atomic:	atomic thread group interval timers.
60   *
61   * This structure contains the version of task_cputime, above, that is
62   * used for thread group CPU timer calculations.
63   */
64  struct thread_group_cputimer {
65  	struct task_cputime_atomic cputime_atomic;
66  };
67  
68  struct multiprocess_signals {
69  	sigset_t signal;
70  	struct hlist_node node;
71  };
72  
73  /*
74   * NOTE! "signal_struct" does not have its own
75   * locking, because a shared signal_struct always
76   * implies a shared sighand_struct, so locking
77   * sighand_struct is always a proper superset of
78   * the locking of signal_struct.
79   */
80  struct signal_struct {
81  	refcount_t		sigcnt;
82  	atomic_t		live;
83  	int			nr_threads;
84  	struct list_head	thread_head;
85  
86  	wait_queue_head_t	wait_chldexit;	/* for wait4() */
87  
88  	/* current thread group signal load-balancing target: */
89  	struct task_struct	*curr_target;
90  
91  	/* shared signal handling: */
92  	struct sigpending	shared_pending;
93  
94  	/* For collecting multiprocess signals during fork */
95  	struct hlist_head	multiprocess;
96  
97  	/* thread group exit support */
98  	int			group_exit_code;
99  	/* overloaded:
100  	 * - notify group_exit_task when ->count is equal to notify_count
101  	 * - everyone except group_exit_task is stopped during signal delivery
102  	 *   of fatal signals, group_exit_task processes the signal.
103  	 */
104  	int			notify_count;
105  	struct task_struct	*group_exit_task;
106  
107  	/* thread group stop support, overloads group_exit_code too */
108  	int			group_stop_count;
109  	unsigned int		flags; /* see SIGNAL_* flags below */
110  
111  	/*
112  	 * PR_SET_CHILD_SUBREAPER marks a process, like a service
113  	 * manager, to re-parent orphan (double-forking) child processes
114  	 * to this process instead of 'init'. The service manager is
115  	 * able to receive SIGCHLD signals and is able to investigate
116  	 * the process until it calls wait(). All children of this
117  	 * process will inherit a flag if they should look for a
118  	 * child_subreaper process at exit.
119  	 */
120  	unsigned int		is_child_subreaper:1;
121  	unsigned int		has_child_subreaper:1;
122  
123  #ifdef CONFIG_POSIX_TIMERS
124  
125  	/* POSIX.1b Interval Timers */
126  	int			posix_timer_id;
127  	struct list_head	posix_timers;
128  
129  	/* ITIMER_REAL timer for the process */
130  	struct hrtimer real_timer;
131  	ktime_t it_real_incr;
132  
133  	/*
134  	 * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
135  	 * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
136  	 * values are defined to 0 and 1 respectively
137  	 */
138  	struct cpu_itimer it[2];
139  
140  	/*
141  	 * Thread group totals for process CPU timers.
142  	 * See thread_group_cputimer(), et al, for details.
143  	 */
144  	struct thread_group_cputimer cputimer;
145  
146  #endif
147  	/* Empty if CONFIG_POSIX_TIMERS=n */
148  	struct posix_cputimers posix_cputimers;
149  
150  	/* PID/PID hash table linkage. */
151  	struct pid *pids[PIDTYPE_MAX];
152  
153  #ifdef CONFIG_NO_HZ_FULL
154  	atomic_t tick_dep_mask;
155  #endif
156  
157  	struct pid *tty_old_pgrp;
158  
159  	/* boolean value for session group leader */
160  	int leader;
161  
162  	struct tty_struct *tty; /* NULL if no tty */
163  
164  #ifdef CONFIG_SCHED_AUTOGROUP
165  	struct autogroup *autogroup;
166  #endif
167  	/*
168  	 * Cumulative resource counters for dead threads in the group,
169  	 * and for reaped dead child processes forked by this group.
170  	 * Live threads maintain their own counters and add to these
171  	 * in __exit_signal, except for the group leader.
172  	 */
173  	seqlock_t stats_lock;
174  	u64 utime, stime, cutime, cstime;
175  	u64 gtime;
176  	u64 cgtime;
177  	struct prev_cputime prev_cputime;
178  	unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
179  	unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
180  	unsigned long inblock, oublock, cinblock, coublock;
181  	unsigned long maxrss, cmaxrss;
182  	struct task_io_accounting ioac;
183  
184  	/*
185  	 * Cumulative ns of schedule CPU time fo dead threads in the
186  	 * group, not including a zombie group leader, (This only differs
187  	 * from jiffies_to_ns(utime + stime) if sched_clock uses something
188  	 * other than jiffies.)
189  	 */
190  	unsigned long long sum_sched_runtime;
191  
192  	/*
193  	 * We don't bother to synchronize most readers of this at all,
194  	 * because there is no reader checking a limit that actually needs
195  	 * to get both rlim_cur and rlim_max atomically, and either one
196  	 * alone is a single word that can safely be read normally.
197  	 * getrlimit/setrlimit use task_lock(current->group_leader) to
198  	 * protect this instead of the siglock, because they really
199  	 * have no need to disable irqs.
200  	 */
201  	struct rlimit rlim[RLIM_NLIMITS];
202  
203  #ifdef CONFIG_BSD_PROCESS_ACCT
204  	struct pacct_struct pacct;	/* per-process accounting information */
205  #endif
206  #ifdef CONFIG_TASKSTATS
207  	struct taskstats *stats;
208  #endif
209  #ifdef CONFIG_AUDIT
210  	unsigned audit_tty;
211  	struct tty_audit_buf *tty_audit_buf;
212  #endif
213  
214  	/*
215  	 * Thread is the potential origin of an oom condition; kill first on
216  	 * oom
217  	 */
218  	bool oom_flag_origin;
219  	short oom_score_adj;		/* OOM kill score adjustment */
220  	short oom_score_adj_min;	/* OOM kill score adjustment min value.
221  					 * Only settable by CAP_SYS_RESOURCE. */
222  	struct mm_struct *oom_mm;	/* recorded mm when the thread group got
223  					 * killed by the oom killer */
224  
225  	struct mutex cred_guard_mutex;	/* guard against foreign influences on
226  					 * credential calculations
227  					 * (notably. ptrace) */
228  } __randomize_layout;
229  
230  /*
231   * Bits in flags field of signal_struct.
232   */
233  #define SIGNAL_STOP_STOPPED	0x00000001 /* job control stop in effect */
234  #define SIGNAL_STOP_CONTINUED	0x00000002 /* SIGCONT since WCONTINUED reap */
235  #define SIGNAL_GROUP_EXIT	0x00000004 /* group exit in progress */
236  #define SIGNAL_GROUP_COREDUMP	0x00000008 /* coredump in progress */
237  /*
238   * Pending notifications to parent.
239   */
240  #define SIGNAL_CLD_STOPPED	0x00000010
241  #define SIGNAL_CLD_CONTINUED	0x00000020
242  #define SIGNAL_CLD_MASK		(SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)
243  
244  #define SIGNAL_UNKILLABLE	0x00000040 /* for init: ignore fatal signals */
245  
246  #define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
247  			  SIGNAL_STOP_CONTINUED)
248  
signal_set_stop_flags(struct signal_struct * sig,unsigned int flags)249  static inline void signal_set_stop_flags(struct signal_struct *sig,
250  					 unsigned int flags)
251  {
252  	WARN_ON(sig->flags & (SIGNAL_GROUP_EXIT|SIGNAL_GROUP_COREDUMP));
253  	sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
254  }
255  
256  /* If true, all threads except ->group_exit_task have pending SIGKILL */
signal_group_exit(const struct signal_struct * sig)257  static inline int signal_group_exit(const struct signal_struct *sig)
258  {
259  	return	(sig->flags & SIGNAL_GROUP_EXIT) ||
260  		(sig->group_exit_task != NULL);
261  }
262  
263  extern void flush_signals(struct task_struct *);
264  extern void ignore_signals(struct task_struct *);
265  extern void flush_signal_handlers(struct task_struct *, int force_default);
266  extern int dequeue_signal(struct task_struct *task,
267  			  sigset_t *mask, kernel_siginfo_t *info);
268  
kernel_dequeue_signal(void)269  static inline int kernel_dequeue_signal(void)
270  {
271  	struct task_struct *task = current;
272  	kernel_siginfo_t __info;
273  	int ret;
274  
275  	spin_lock_irq(&task->sighand->siglock);
276  	ret = dequeue_signal(task, &task->blocked, &__info);
277  	spin_unlock_irq(&task->sighand->siglock);
278  
279  	return ret;
280  }
281  
kernel_signal_stop(void)282  static inline void kernel_signal_stop(void)
283  {
284  	spin_lock_irq(&current->sighand->siglock);
285  	if (current->jobctl & JOBCTL_STOP_DEQUEUED)
286  		set_special_state(TASK_STOPPED);
287  	spin_unlock_irq(&current->sighand->siglock);
288  
289  	schedule();
290  }
291  #ifdef __ARCH_SI_TRAPNO
292  # define ___ARCH_SI_TRAPNO(_a1) , _a1
293  #else
294  # define ___ARCH_SI_TRAPNO(_a1)
295  #endif
296  #ifdef __ia64__
297  # define ___ARCH_SI_IA64(_a1, _a2, _a3) , _a1, _a2, _a3
298  #else
299  # define ___ARCH_SI_IA64(_a1, _a2, _a3)
300  #endif
301  
302  int force_sig_fault_to_task(int sig, int code, void __user *addr
303  	___ARCH_SI_TRAPNO(int trapno)
304  	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
305  	, struct task_struct *t);
306  int force_sig_fault(int sig, int code, void __user *addr
307  	___ARCH_SI_TRAPNO(int trapno)
308  	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr));
309  int send_sig_fault(int sig, int code, void __user *addr
310  	___ARCH_SI_TRAPNO(int trapno)
311  	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
312  	, struct task_struct *t);
313  
314  int force_sig_mceerr(int code, void __user *, short);
315  int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
316  
317  int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
318  int force_sig_pkuerr(void __user *addr, u32 pkey);
319  
320  int force_sig_ptrace_errno_trap(int errno, void __user *addr);
321  
322  extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
323  extern void force_sigsegv(int sig);
324  extern int force_sig_info(struct kernel_siginfo *);
325  extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
326  extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
327  extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
328  				const struct cred *);
329  extern int kill_pgrp(struct pid *pid, int sig, int priv);
330  extern int kill_pid(struct pid *pid, int sig, int priv);
331  extern __must_check bool do_notify_parent(struct task_struct *, int);
332  extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
333  extern void force_sig(int);
334  extern int send_sig(int, struct task_struct *, int);
335  extern int zap_other_threads(struct task_struct *p);
336  extern struct sigqueue *sigqueue_alloc(void);
337  extern void sigqueue_free(struct sigqueue *);
338  extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
339  extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
340  
restart_syscall(void)341  static inline int restart_syscall(void)
342  {
343  	set_tsk_thread_flag(current, TIF_SIGPENDING);
344  	return -ERESTARTNOINTR;
345  }
346  
signal_pending(struct task_struct * p)347  static inline int signal_pending(struct task_struct *p)
348  {
349  	return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
350  }
351  
__fatal_signal_pending(struct task_struct * p)352  static inline int __fatal_signal_pending(struct task_struct *p)
353  {
354  	return unlikely(sigismember(&p->pending.signal, SIGKILL));
355  }
356  
fatal_signal_pending(struct task_struct * p)357  static inline int fatal_signal_pending(struct task_struct *p)
358  {
359  	return signal_pending(p) && __fatal_signal_pending(p);
360  }
361  
signal_pending_state(long state,struct task_struct * p)362  static inline int signal_pending_state(long state, struct task_struct *p)
363  {
364  	if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
365  		return 0;
366  	if (!signal_pending(p))
367  		return 0;
368  
369  	return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
370  }
371  
372  /*
373   * Reevaluate whether the task has signals pending delivery.
374   * Wake the task if so.
375   * This is required every time the blocked sigset_t changes.
376   * callers must hold sighand->siglock.
377   */
378  extern void recalc_sigpending_and_wake(struct task_struct *t);
379  extern void recalc_sigpending(void);
380  extern void calculate_sigpending(void);
381  
382  extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
383  
signal_wake_up(struct task_struct * t,bool resume)384  static inline void signal_wake_up(struct task_struct *t, bool resume)
385  {
386  	signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
387  }
ptrace_signal_wake_up(struct task_struct * t,bool resume)388  static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
389  {
390  	signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
391  }
392  
393  void task_join_group_stop(struct task_struct *task);
394  
395  #ifdef TIF_RESTORE_SIGMASK
396  /*
397   * Legacy restore_sigmask accessors.  These are inefficient on
398   * SMP architectures because they require atomic operations.
399   */
400  
401  /**
402   * set_restore_sigmask() - make sure saved_sigmask processing gets done
403   *
404   * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code
405   * will run before returning to user mode, to process the flag.  For
406   * all callers, TIF_SIGPENDING is already set or it's no harm to set
407   * it.  TIF_RESTORE_SIGMASK need not be in the set of bits that the
408   * arch code will notice on return to user mode, in case those bits
409   * are scarce.  We set TIF_SIGPENDING here to ensure that the arch
410   * signal code always gets run when TIF_RESTORE_SIGMASK is set.
411   */
set_restore_sigmask(void)412  static inline void set_restore_sigmask(void)
413  {
414  	set_thread_flag(TIF_RESTORE_SIGMASK);
415  }
416  
clear_tsk_restore_sigmask(struct task_struct * task)417  static inline void clear_tsk_restore_sigmask(struct task_struct *task)
418  {
419  	clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
420  }
421  
clear_restore_sigmask(void)422  static inline void clear_restore_sigmask(void)
423  {
424  	clear_thread_flag(TIF_RESTORE_SIGMASK);
425  }
test_tsk_restore_sigmask(struct task_struct * task)426  static inline bool test_tsk_restore_sigmask(struct task_struct *task)
427  {
428  	return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
429  }
test_restore_sigmask(void)430  static inline bool test_restore_sigmask(void)
431  {
432  	return test_thread_flag(TIF_RESTORE_SIGMASK);
433  }
test_and_clear_restore_sigmask(void)434  static inline bool test_and_clear_restore_sigmask(void)
435  {
436  	return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
437  }
438  
439  #else	/* TIF_RESTORE_SIGMASK */
440  
441  /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
set_restore_sigmask(void)442  static inline void set_restore_sigmask(void)
443  {
444  	current->restore_sigmask = true;
445  }
clear_tsk_restore_sigmask(struct task_struct * task)446  static inline void clear_tsk_restore_sigmask(struct task_struct *task)
447  {
448  	task->restore_sigmask = false;
449  }
clear_restore_sigmask(void)450  static inline void clear_restore_sigmask(void)
451  {
452  	current->restore_sigmask = false;
453  }
test_restore_sigmask(void)454  static inline bool test_restore_sigmask(void)
455  {
456  	return current->restore_sigmask;
457  }
test_tsk_restore_sigmask(struct task_struct * task)458  static inline bool test_tsk_restore_sigmask(struct task_struct *task)
459  {
460  	return task->restore_sigmask;
461  }
test_and_clear_restore_sigmask(void)462  static inline bool test_and_clear_restore_sigmask(void)
463  {
464  	if (!current->restore_sigmask)
465  		return false;
466  	current->restore_sigmask = false;
467  	return true;
468  }
469  #endif
470  
restore_saved_sigmask(void)471  static inline void restore_saved_sigmask(void)
472  {
473  	if (test_and_clear_restore_sigmask())
474  		__set_current_blocked(&current->saved_sigmask);
475  }
476  
477  extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
478  
restore_saved_sigmask_unless(bool interrupted)479  static inline void restore_saved_sigmask_unless(bool interrupted)
480  {
481  	if (interrupted)
482  		WARN_ON(!test_thread_flag(TIF_SIGPENDING));
483  	else
484  		restore_saved_sigmask();
485  }
486  
sigmask_to_save(void)487  static inline sigset_t *sigmask_to_save(void)
488  {
489  	sigset_t *res = &current->blocked;
490  	if (unlikely(test_restore_sigmask()))
491  		res = &current->saved_sigmask;
492  	return res;
493  }
494  
kill_cad_pid(int sig,int priv)495  static inline int kill_cad_pid(int sig, int priv)
496  {
497  	return kill_pid(cad_pid, sig, priv);
498  }
499  
500  /* These can be the second arg to send_sig_info/send_group_sig_info.  */
501  #define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
502  #define SEND_SIG_PRIV	((struct kernel_siginfo *) 1)
503  
504  /*
505   * True if we are on the alternate signal stack.
506   */
on_sig_stack(unsigned long sp)507  static inline int on_sig_stack(unsigned long sp)
508  {
509  	/*
510  	 * If the signal stack is SS_AUTODISARM then, by construction, we
511  	 * can't be on the signal stack unless user code deliberately set
512  	 * SS_AUTODISARM when we were already on it.
513  	 *
514  	 * This improves reliability: if user state gets corrupted such that
515  	 * the stack pointer points very close to the end of the signal stack,
516  	 * then this check will enable the signal to be handled anyway.
517  	 */
518  	if (current->sas_ss_flags & SS_AUTODISARM)
519  		return 0;
520  
521  #ifdef CONFIG_STACK_GROWSUP
522  	return sp >= current->sas_ss_sp &&
523  		sp - current->sas_ss_sp < current->sas_ss_size;
524  #else
525  	return sp > current->sas_ss_sp &&
526  		sp - current->sas_ss_sp <= current->sas_ss_size;
527  #endif
528  }
529  
sas_ss_flags(unsigned long sp)530  static inline int sas_ss_flags(unsigned long sp)
531  {
532  	if (!current->sas_ss_size)
533  		return SS_DISABLE;
534  
535  	return on_sig_stack(sp) ? SS_ONSTACK : 0;
536  }
537  
sas_ss_reset(struct task_struct * p)538  static inline void sas_ss_reset(struct task_struct *p)
539  {
540  	p->sas_ss_sp = 0;
541  	p->sas_ss_size = 0;
542  	p->sas_ss_flags = SS_DISABLE;
543  }
544  
sigsp(unsigned long sp,struct ksignal * ksig)545  static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
546  {
547  	if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp))
548  #ifdef CONFIG_STACK_GROWSUP
549  		return current->sas_ss_sp;
550  #else
551  		return current->sas_ss_sp + current->sas_ss_size;
552  #endif
553  	return sp;
554  }
555  
556  extern void __cleanup_sighand(struct sighand_struct *);
557  extern void flush_itimer_signals(void);
558  
559  #define tasklist_empty() \
560  	list_empty(&init_task.tasks)
561  
562  #define next_task(p) \
563  	list_entry_rcu((p)->tasks.next, struct task_struct, tasks)
564  
565  #define for_each_process(p) \
566  	for (p = &init_task ; (p = next_task(p)) != &init_task ; )
567  
568  extern bool current_is_single_threaded(void);
569  
570  /*
571   * Careful: do_each_thread/while_each_thread is a double loop so
572   *          'break' will not work as expected - use goto instead.
573   */
574  #define do_each_thread(g, t) \
575  	for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do
576  
577  #define while_each_thread(g, t) \
578  	while ((t = next_thread(t)) != g)
579  
580  #define __for_each_thread(signal, t)	\
581  	list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node)
582  
583  #define for_each_thread(p, t)		\
584  	__for_each_thread((p)->signal, t)
585  
586  /* Careful: this is a double loop, 'break' won't work as expected. */
587  #define for_each_process_thread(p, t)	\
588  	for_each_process(p) for_each_thread(p, t)
589  
590  typedef int (*proc_visitor)(struct task_struct *p, void *data);
591  void walk_process_tree(struct task_struct *top, proc_visitor, void *);
592  
593  static inline
task_pid_type(struct task_struct * task,enum pid_type type)594  struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
595  {
596  	struct pid *pid;
597  	if (type == PIDTYPE_PID)
598  		pid = task_pid(task);
599  	else
600  		pid = task->signal->pids[type];
601  	return pid;
602  }
603  
task_tgid(struct task_struct * task)604  static inline struct pid *task_tgid(struct task_struct *task)
605  {
606  	return task->signal->pids[PIDTYPE_TGID];
607  }
608  
609  /*
610   * Without tasklist or RCU lock it is not safe to dereference
611   * the result of task_pgrp/task_session even if task == current,
612   * we can race with another thread doing sys_setsid/sys_setpgid.
613   */
task_pgrp(struct task_struct * task)614  static inline struct pid *task_pgrp(struct task_struct *task)
615  {
616  	return task->signal->pids[PIDTYPE_PGID];
617  }
618  
task_session(struct task_struct * task)619  static inline struct pid *task_session(struct task_struct *task)
620  {
621  	return task->signal->pids[PIDTYPE_SID];
622  }
623  
get_nr_threads(struct task_struct * task)624  static inline int get_nr_threads(struct task_struct *task)
625  {
626  	return task->signal->nr_threads;
627  }
628  
thread_group_leader(struct task_struct * p)629  static inline bool thread_group_leader(struct task_struct *p)
630  {
631  	return p->exit_signal >= 0;
632  }
633  
634  /* Do to the insanities of de_thread it is possible for a process
635   * to have the pid of the thread group leader without actually being
636   * the thread group leader.  For iteration through the pids in proc
637   * all we care about is that we have a task with the appropriate
638   * pid, we don't actually care if we have the right task.
639   */
has_group_leader_pid(struct task_struct * p)640  static inline bool has_group_leader_pid(struct task_struct *p)
641  {
642  	return task_pid(p) == task_tgid(p);
643  }
644  
645  static inline
same_thread_group(struct task_struct * p1,struct task_struct * p2)646  bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
647  {
648  	return p1->signal == p2->signal;
649  }
650  
next_thread(const struct task_struct * p)651  static inline struct task_struct *next_thread(const struct task_struct *p)
652  {
653  	return list_entry_rcu(p->thread_group.next,
654  			      struct task_struct, thread_group);
655  }
656  
thread_group_empty(struct task_struct * p)657  static inline int thread_group_empty(struct task_struct *p)
658  {
659  	return list_empty(&p->thread_group);
660  }
661  
662  #define delay_group_leader(p) \
663  		(thread_group_leader(p) && !thread_group_empty(p))
664  
665  extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
666  							unsigned long *flags);
667  
lock_task_sighand(struct task_struct * task,unsigned long * flags)668  static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
669  						       unsigned long *flags)
670  {
671  	struct sighand_struct *ret;
672  
673  	ret = __lock_task_sighand(task, flags);
674  	(void)__cond_lock(&task->sighand->siglock, ret);
675  	return ret;
676  }
677  
unlock_task_sighand(struct task_struct * task,unsigned long * flags)678  static inline void unlock_task_sighand(struct task_struct *task,
679  						unsigned long *flags)
680  {
681  	spin_unlock_irqrestore(&task->sighand->siglock, *flags);
682  }
683  
task_rlimit(const struct task_struct * task,unsigned int limit)684  static inline unsigned long task_rlimit(const struct task_struct *task,
685  		unsigned int limit)
686  {
687  	return READ_ONCE(task->signal->rlim[limit].rlim_cur);
688  }
689  
task_rlimit_max(const struct task_struct * task,unsigned int limit)690  static inline unsigned long task_rlimit_max(const struct task_struct *task,
691  		unsigned int limit)
692  {
693  	return READ_ONCE(task->signal->rlim[limit].rlim_max);
694  }
695  
rlimit(unsigned int limit)696  static inline unsigned long rlimit(unsigned int limit)
697  {
698  	return task_rlimit(current, limit);
699  }
700  
rlimit_max(unsigned int limit)701  static inline unsigned long rlimit_max(unsigned int limit)
702  {
703  	return task_rlimit_max(current, limit);
704  }
705  
706  #endif /* _LINUX_SCHED_SIGNAL_H */
707