TOMOYO Linux Cross Reference
Linux/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;
 }
 
 /* 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);
 }
 
 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;
 }
 
 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();
 }
 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 int kill_proc_info(int, struct siginfo *, pid_t);
 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;
 }
 
 static inline int signal_pending(struct task_struct *p)
 {
         return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
 }
 
 static inline int __fatal_signal_pending(struct task_struct *p)
 {
         return unlikely(sigismember(&p->pending.signal, SIGKILL));
 }
 
 static inline int fatal_signal_pending(struct task_struct *p)
 {
         return signal_pending(p) && __fatal_signal_pending(p);
 }
 
 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);
 }
 
 /*
  * 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);
 }
 static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
 {
         signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
 }
 
 #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));
 }
 static inline void clear_restore_sigmask(void)
 {
         clear_thread_flag(TIF_RESTORE_SIGMASK);
 }
 static inline bool test_restore_sigmask(void)
 {
         return test_thread_flag(TIF_RESTORE_SIGMASK);
 }
 static inline bool test_and_clear_restore_sigmask(void)
 {
         return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK);
 }
 
 #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));
 }
 static inline void clear_restore_sigmask(void)
 {
         current->restore_sigmask = false;
 }
 static inline bool test_restore_sigmask(void)
 {
         return current->restore_sigmask;
 }
 static inline bool test_and_clear_restore_sigmask(void)
 {
         if (!current->restore_sigmask)
                 return false;
         current->restore_sigmask = false;
         return true;
 }
 #endif
 
 static inline void restore_saved_sigmask(void)
 {
         if (test_and_clear_restore_sigmask())
                 __set_current_blocked(&current->saved_sigmask);
 }
 
 static inline sigset_t *sigmask_to_save(void)
 {
         sigset_t *res = &current->blocked;
         if (unlikely(test_restore_sigmask()))
                 res = &current->saved_sigmask;
         return res;
 }
 
 static inline int kill_cad_pid(int sig, int priv)
 {
         return kill_pid(cad_pid, sig, priv);
 }
 
 /* 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
 }
 
 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;
 }
 
 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;
 }
 
 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;
 }
 
 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;
 }
 
 static inline bool thread_group_leader(struct task_struct *p)
 {
         return p->exit_signal >= 0;
 }
 
 /* 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;
 }
 
 static inline
 bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
 {
         return p1->signal == p2->signal;
 }
 
 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);
 }
 
 static inline int thread_group_empty(struct task_struct *p)
 {
         return list_empty(&p->thread_group);
 }
 
 #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;
 }
 
 static inline void unlock_task_sighand(struct task_struct *tsk,
                                                 unsigned long *flags)
 {
         spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
 }
 
 static inline unsigned long task_rlimit(const struct task_struct *tsk,
                 unsigned int limit)
 {
         return READ_ONCE(tsk->signal->rlim[limit].rlim_cur);
 }
 
 static inline unsigned long task_rlimit_max(const struct task_struct *tsk,
                 unsigned int limit)
 {
         return READ_ONCE(tsk->signal->rlim[limit].rlim_max);
 }
 
 static inline unsigned long rlimit(unsigned int limit)
 {
         return task_rlimit(current, limit);
 }
 
 static inline unsigned long rlimit_max(unsigned int limit)
 {
         return task_rlimit_max(current, limit);
 }
 
 #endif /* _LINUX_SCHED_SIGNAL_H */
 

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