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Release 4.12 include/linux/sched/signal.h

#ifndef _LINUX_SCHED_SIGNAL_H

#define _LINUX_SCHED_SIGNAL_H

#include <linux/rculist.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/sched/jobctl.h>
#include <linux/sched/task.h>
#include <linux/cred.h>

/*
 * Types defining task->signal and task->sighand and APIs using them:
 */


struct sighand_struct {
	
atomic_t		count;
	
struct k_sigaction	action[_NSIG];
	
spinlock_t		siglock;
	
wait_queue_head_t	signalfd_wqh;
};

/*
 * Per-process accounting stats:
 */

struct pacct_struct {
	
int			ac_flag;
	
long			ac_exitcode;
	
unsigned long		ac_mem;
	

u64			ac_utime, ac_stime;
	

unsigned long		ac_minflt, ac_majflt;
};


struct cpu_itimer {
	
u64 expires;
	
u64 incr;
};

/*
 * This is the atomic variant of task_cputime, which can be used for
 * storing and updating task_cputime statistics without locking.
 */

struct task_cputime_atomic {
	
atomic64_t utime;
	
atomic64_t stime;
	
atomic64_t sum_exec_runtime;
};


#define INIT_CPUTIME_ATOMIC \
	(struct task_cputime_atomic) {                          \
                .utime = ATOMIC64_INIT(0),                      \
                .stime = ATOMIC64_INIT(0),                      \
                .sum_exec_runtime = ATOMIC64_INIT(0),           \
        }
/**
 * struct thread_group_cputimer - thread group interval timer counts
 * @cputime_atomic:     atomic thread group interval timers.
 * @running:            true when there are timers running and
 *                      @cputime_atomic receives updates.
 * @checking_timer:     true when a thread in the group is in the
 *                      process of checking for thread group timers.
 *
 * This structure contains the version of task_cputime, above, that is
 * used for thread group CPU timer calculations.
 */

struct thread_group_cputimer {
	
struct task_cputime_atomic cputime_atomic;
	
bool running;
	
bool checking_timer;
};

/*
 * NOTE! "signal_struct" does not have its own
 * locking, because a shared signal_struct always
 * implies a shared sighand_struct, so locking
 * sighand_struct is always a proper superset of
 * the locking of signal_struct.
 */

struct signal_struct {
	
atomic_t		sigcnt;
	
atomic_t		live;
	
int			nr_threads;
	
struct list_head	thread_head;

	
wait_queue_head_t	wait_chldexit;	/* for wait4() */

	/* current thread group signal load-balancing target: */
	
struct task_struct	*curr_target;

	/* shared signal handling: */
	
struct sigpending	shared_pending;

	/* thread group exit support */
	
int			group_exit_code;
	/* overloaded:
         * - notify group_exit_task when ->count is equal to notify_count
         * - everyone except group_exit_task is stopped during signal delivery
         *   of fatal signals, group_exit_task processes the signal.
         */
	
int			notify_count;
	
struct task_struct	*group_exit_task;

	/* thread group stop support, overloads group_exit_code too */
	
int			group_stop_count;
	
unsigned int		flags; /* see SIGNAL_* flags below */

	/*
         * PR_SET_CHILD_SUBREAPER marks a process, like a service
         * manager, to re-parent orphan (double-forking) child processes
         * to this process instead of 'init'. The service manager is
         * able to receive SIGCHLD signals and is able to investigate
         * the process until it calls wait(). All children of this
         * process will inherit a flag if they should look for a
         * child_subreaper process at exit.
         */
	
unsigned int		is_child_subreaper:1;
	
unsigned int		has_child_subreaper:1;

#ifdef CONFIG_POSIX_TIMERS

	/* POSIX.1b Interval Timers */
	
int			posix_timer_id;
	
struct list_head	posix_timers;

	/* ITIMER_REAL timer for the process */
	
struct hrtimer real_timer;
	
ktime_t it_real_incr;

	/*
         * ITIMER_PROF and ITIMER_VIRTUAL timers for the process, we use
         * CPUCLOCK_PROF and CPUCLOCK_VIRT for indexing array as these
         * values are defined to 0 and 1 respectively
         */
	
struct cpu_itimer it[2];

	/*
         * Thread group totals for process CPU timers.
         * See thread_group_cputimer(), et al, for details.
         */
	
struct thread_group_cputimer cputimer;

	/* Earliest-expiration cache. */
	
struct task_cputime cputime_expires;

	
struct list_head cpu_timers[3];

#endif

	
struct pid *leader_pid;

#ifdef CONFIG_NO_HZ_FULL
	
atomic_t tick_dep_mask;
#endif

	
struct pid *tty_old_pgrp;

	/* boolean value for session group leader */
	
int leader;

	
struct tty_struct *tty; /* NULL if no tty */

#ifdef CONFIG_SCHED_AUTOGROUP
	
struct autogroup *autogroup;
#endif
	/*
         * Cumulative resource counters for dead threads in the group,
         * and for reaped dead child processes forked by this group.
         * Live threads maintain their own counters and add to these
         * in __exit_signal, except for the group leader.
         */
	
seqlock_t stats_lock;
	



u64 utime, stime, cutime, cstime;
	
u64 gtime;
	
u64 cgtime;
	
struct prev_cputime prev_cputime;
	



unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
	



unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;
	



unsigned long inblock, oublock, cinblock, coublock;
	

unsigned long maxrss, cmaxrss;
	
struct task_io_accounting ioac;

	/*
         * Cumulative ns of schedule CPU time fo dead threads in the
         * group, not including a zombie group leader, (This only differs
         * from jiffies_to_ns(utime + stime) if sched_clock uses something
         * other than jiffies.)
         */
	
unsigned long long sum_sched_runtime;

	/*
         * We don't bother to synchronize most readers of this at all,
         * because there is no reader checking a limit that actually needs
         * to get both rlim_cur and rlim_max atomically, and either one
         * alone is a single word that can safely be read normally.
         * getrlimit/setrlimit use task_lock(current->group_leader) to
         * protect this instead of the siglock, because they really
         * have no need to disable irqs.
         */
	
struct rlimit rlim[RLIM_NLIMITS];

#ifdef CONFIG_BSD_PROCESS_ACCT
	
struct pacct_struct pacct;	/* per-process accounting information */
#endif
#ifdef CONFIG_TASKSTATS
	
struct taskstats *stats;
#endif
#ifdef CONFIG_AUDIT
	
unsigned audit_tty;
	
struct tty_audit_buf *tty_audit_buf;
#endif

	/*
         * Thread is the potential origin of an oom condition; kill first on
         * oom
         */
	
bool oom_flag_origin;
	
short oom_score_adj;		/* OOM kill score adjustment */
	
short oom_score_adj_min;	/* OOM kill score adjustment min value.
                                         * Only settable by CAP_SYS_RESOURCE. */
	
struct mm_struct *oom_mm;	/* recorded mm when the thread group got
                                         * killed by the oom killer */

	
struct mutex cred_guard_mutex;	/* guard against foreign influences on
                                         * credential calculations
                                         * (notably. ptrace) */
};

/*
 * Bits in flags field of signal_struct.
 */

#define SIGNAL_STOP_STOPPED	0x00000001 
/* job control stop in effect */

#define SIGNAL_STOP_CONTINUED	0x00000002 
/* SIGCONT since WCONTINUED reap */

#define SIGNAL_GROUP_EXIT	0x00000004 
/* group exit in progress */

#define SIGNAL_GROUP_COREDUMP	0x00000008 
/* coredump in progress */
/*
 * Pending notifications to parent.
 */

#define SIGNAL_CLD_STOPPED	0x00000010

#define SIGNAL_CLD_CONTINUED	0x00000020

#define SIGNAL_CLD_MASK		(SIGNAL_CLD_STOPPED|SIGNAL_CLD_CONTINUED)


#define SIGNAL_UNKILLABLE	0x00000040 
/* for init: ignore fatal signals */


#define SIGNAL_STOP_MASK (SIGNAL_CLD_MASK | SIGNAL_STOP_STOPPED | \
                          SIGNAL_STOP_CONTINUED)


static inline void signal_set_stop_flags(struct signal_struct *sig, unsigned int flags) { WARN_ON(sig->flags & (SIGNAL_GROUP_EXIT|SIGNAL_GROUP_COREDUMP)); sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags; }

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/* If true, all threads except ->group_exit_task have pending SIGKILL */
static inline int signal_group_exit(const struct signal_struct *sig) { return (sig->flags & SIGNAL_GROUP_EXIT) || (sig->group_exit_task != NULL); }

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extern void flush_signals(struct task_struct *); extern void ignore_signals(struct task_struct *); extern void flush_signal_handlers(struct task_struct *, int force_default); extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info);
static inline int kernel_dequeue_signal(siginfo_t *info) { struct task_struct *tsk = current; siginfo_t __info; int ret; spin_lock_irq(&tsk->sighand->siglock); ret = dequeue_signal(tsk, &tsk->blocked, info ?: &__info); spin_unlock_irq(&tsk->sighand->siglock); return ret; }

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static inline void kernel_signal_stop(void) { spin_lock_irq(&current->sighand->siglock); if (current->jobctl & JOBCTL_STOP_DEQUEUED) __set_current_state(TASK_STOPPED); spin_unlock_irq(&current->sighand->siglock); schedule(); }

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extern int send_sig_info(int, struct siginfo *, struct task_struct *); extern int force_sigsegv(int, struct task_struct *); extern int force_sig_info(int, struct siginfo *, struct task_struct *); extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp); extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid); extern int kill_pid_info_as_cred(int, struct siginfo *, struct pid *, const struct cred *, u32); extern int kill_pgrp(struct pid *pid, int sig, int priv); extern int kill_pid(struct pid *pid, int sig, int priv); extern __must_check bool do_notify_parent(struct task_struct *, int); extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent); extern void force_sig(int, struct task_struct *); extern int send_sig(int, struct task_struct *, int); extern int zap_other_threads(struct task_struct *p); extern struct sigqueue *sigqueue_alloc(void); extern void sigqueue_free(struct sigqueue *); extern int send_sigqueue(struct sigqueue *, struct task_struct *, int group); extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
static inline int restart_syscall(void) { set_tsk_thread_flag(current, TIF_SIGPENDING); return -ERESTARTNOINTR; }

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static inline int signal_pending(struct task_struct *p) { return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING)); }

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static inline int __fatal_signal_pending(struct task_struct *p) { return unlikely(sigismember(&p->pending.signal, SIGKILL)); }

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static inline int fatal_signal_pending(struct task_struct *p) { return signal_pending(p) && __fatal_signal_pending(p); }

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static inline int signal_pending_state(long state, struct task_struct *p) { if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL))) return 0; if (!signal_pending(p)) return 0; return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p); }

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/* * Reevaluate whether the task has signals pending delivery. * Wake the task if so. * This is required every time the blocked sigset_t changes. * callers must hold sighand->siglock. */ extern void recalc_sigpending_and_wake(struct task_struct *t); extern void recalc_sigpending(void); extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
static inline void signal_wake_up(struct task_struct *t, bool resume) { signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0); }

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static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume) { signal_wake_up_state(t, resume ? __TASK_TRACED : 0); }

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#ifdef TIF_RESTORE_SIGMASK /* * Legacy restore_sigmask accessors. These are inefficient on * SMP architectures because they require atomic operations. */ /** * set_restore_sigmask() - make sure saved_sigmask processing gets done * * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code * will run before returning to user mode, to process the flag. For * all callers, TIF_SIGPENDING is already set or it's no harm to set * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the * arch code will notice on return to user mode, in case those bits * are scarce. We set TIF_SIGPENDING here to ensure that the arch * signal code always gets run when TIF_RESTORE_SIGMASK is set. */
static inline void set_restore_sigmask(void) { set_thread_flag(TIF_RESTORE_SIGMASK); WARN_ON(!test_thread_flag(TIF_SIGPENDING)); }

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static inline void clear_restore_sigmask(void) { clear_thread_flag(TIF_RESTORE_SIGMASK); }

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static inline bool test_restore_sigmask(void) { return test_thread_flag(TIF_RESTORE_SIGMASK); }

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static inline bool test_and_clear_restore_sigmask(void) { return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK); }

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#else /* TIF_RESTORE_SIGMASK */ /* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */
static inline void set_restore_sigmask(void) { current->restore_sigmask = true; WARN_ON(!test_thread_flag(TIF_SIGPENDING)); }

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static inline void clear_restore_sigmask(void) { current->restore_sigmask = false; }

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static inline bool test_restore_sigmask(void) { return current->restore_sigmask; }

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static inline bool test_and_clear_restore_sigmask(void) { if (!current->restore_sigmask) return false; current->restore_sigmask = false; return true; }

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#endif
static inline void restore_saved_sigmask(void) { if (test_and_clear_restore_sigmask()) __set_current_blocked(&current->saved_sigmask); }

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static inline sigset_t *sigmask_to_save(void) { sigset_t *res = &current->blocked; if (unlikely(test_restore_sigmask())) res = &current->saved_sigmask; return res; }

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static inline int kill_cad_pid(int sig, int priv) { return kill_pid(cad_pid, sig, priv); }

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/* These can be the second arg to send_sig_info/send_group_sig_info. */ #define SEND_SIG_NOINFO ((struct siginfo *) 0) #define SEND_SIG_PRIV ((struct siginfo *) 1) #define SEND_SIG_FORCED ((struct siginfo *) 2) /* * True if we are on the alternate signal stack. */
static inline int on_sig_stack(unsigned long sp) { /* * If the signal stack is SS_AUTODISARM then, by construction, we * can't be on the signal stack unless user code deliberately set * SS_AUTODISARM when we were already on it. * * This improves reliability: if user state gets corrupted such that * the stack pointer points very close to the end of the signal stack, * then this check will enable the signal to be handled anyway. */ if (current->sas_ss_flags & SS_AUTODISARM) return 0; #ifdef CONFIG_STACK_GROWSUP return sp >= current->sas_ss_sp && sp - current->sas_ss_sp < current->sas_ss_size; #else return sp > current->sas_ss_sp && sp - current->sas_ss_sp <= current->sas_ss_size; #endif }

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static inline int sas_ss_flags(unsigned long sp) { if (!current->sas_ss_size) return SS_DISABLE; return on_sig_stack(sp) ? SS_ONSTACK : 0; }

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static inline void sas_ss_reset(struct task_struct *p) { p->sas_ss_sp = 0; p->sas_ss_size = 0; p->sas_ss_flags = SS_DISABLE; }

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static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig) { if (unlikely((ksig->ka.sa.sa_flags & SA_ONSTACK)) && ! sas_ss_flags(sp)) #ifdef CONFIG_STACK_GROWSUP return current->sas_ss_sp; #else return current->sas_ss_sp + current->sas_ss_size; #endif return sp; }

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extern void __cleanup_sighand(struct sighand_struct *); extern void flush_itimer_signals(void); #define tasklist_empty() \ list_empty(&init_task.tasks) #define next_task(p) \ list_entry_rcu((p)->tasks.next, struct task_struct, tasks) #define for_each_process(p) \ for (p = &init_task ; (p = next_task(p)) != &init_task ; ) extern bool current_is_single_threaded(void); /* * Careful: do_each_thread/while_each_thread is a double loop so * 'break' will not work as expected - use goto instead. */ #define do_each_thread(g, t) \ for (g = t = &init_task ; (g = t = next_task(g)) != &init_task ; ) do #define while_each_thread(g, t) \ while ((t = next_thread(t)) != g) #define __for_each_thread(signal, t) \ list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node) #define for_each_thread(p, t) \ __for_each_thread((p)->signal, t) /* Careful: this is a double loop, 'break' won't work as expected. */ #define for_each_process_thread(p, t) \ for_each_process(p) for_each_thread(p, t) typedef int (*proc_visitor)(struct task_struct *p, void *data); void walk_process_tree(struct task_struct *top, proc_visitor, void *);
static inline int get_nr_threads(struct task_struct *tsk) { return tsk->signal->nr_threads; }

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static inline bool thread_group_leader(struct task_struct *p) { return p->exit_signal >= 0; }

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/* Do to the insanities of de_thread it is possible for a process * to have the pid of the thread group leader without actually being * the thread group leader. For iteration through the pids in proc * all we care about is that we have a task with the appropriate * pid, we don't actually care if we have the right task. */
static inline bool has_group_leader_pid(struct task_struct *p) { return task_pid(p) == p->signal->leader_pid; }

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static inline bool same_thread_group(struct task_struct *p1, struct task_struct *p2) { return p1->signal == p2->signal; }

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static inline struct task_struct *next_thread(const struct task_struct *p) { return list_entry_rcu(p->thread_group.next, struct task_struct, thread_group); }

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static inline int thread_group_empty(struct task_struct *p) { return list_empty(&p->thread_group); }

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#define delay_group_leader(p) \ (thread_group_leader(p) && !thread_group_empty(p)) extern struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, unsigned long *flags);
static inline struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags) { struct sighand_struct *ret; ret = __lock_task_sighand(tsk, flags); (void)__cond_lock(&tsk->sighand->siglock, ret); return ret; }

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static inline void unlock_task_sighand(struct task_struct *tsk, unsigned long *flags) { spin_unlock_irqrestore(&tsk->sighand->siglock, *flags); }

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static inline unsigned long task_rlimit(const struct task_struct *tsk, unsigned int limit) { return READ_ONCE(tsk->signal->rlim[limit].rlim_cur); }

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static inline unsigned long task_rlimit_max(const struct task_struct *tsk, unsigned int limit) { return READ_ONCE(tsk->signal->rlim[limit].rlim_max); }

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static inline unsigned long rlimit(unsigned int limit) { return task_rlimit(current, limit); }

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static inline unsigned long rlimit_max(unsigned int limit) { return task_rlimit_max(current, limit); }

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#endif /* _LINUX_SCHED_SIGNAL_H */

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