linux/include/linux/sched/signal.h

/* SPDX-License-Identifier: GPL-2.0 */
#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>
#include <linux/refcount.h>
#include <linux/pid.h>
#include <linux/posix-timers.h>
#include <linux/mm_types.h>
#include <asm/ptrace.h>

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

struct sighand_struct { … };

/*
 * Per-process accounting stats:
 */
struct pacct_struct { … };

struct cpu_itimer { … };

/*
 * 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 { … };

#define INIT_CPUTIME_ATOMIC …
/**
 * struct thread_group_cputimer - thread group interval timer counts
 * @cputime_atomic:	atomic thread group interval timers.
 *
 * This structure contains the version of task_cputime, above, that is
 * used for thread group CPU timer calculations.
 */
struct thread_group_cputimer { … };

struct multiprocess_signals { … };

struct core_thread { … };

struct core_state { … };

/*
 * 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 { … } __randomize_layout;

/*
 * Bits in flags field of signal_struct.
 */
#define SIGNAL_STOP_STOPPED …
#define SIGNAL_STOP_CONTINUED …
#define SIGNAL_GROUP_EXIT …
/*
 * Pending notifications to parent.
 */
#define SIGNAL_CLD_STOPPED …
#define SIGNAL_CLD_CONTINUED …
#define SIGNAL_CLD_MASK …

#define SIGNAL_UNKILLABLE …

#define SIGNAL_STOP_MASK …

static inline void signal_set_stop_flags(struct signal_struct *sig,
					 unsigned int flags)
{ … }

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(sigset_t *mask, kernel_siginfo_t *info, enum pid_type *type);

static inline int kernel_dequeue_signal(void)
{ … }

static inline void kernel_signal_stop(void)
{ … }

int force_sig_fault_to_task(int sig, int code, void __user *addr,
			    struct task_struct *t);
int force_sig_fault(int sig, int code, void __user *addr);
int send_sig_fault(int sig, int code, void __user *addr, struct task_struct *t);

int force_sig_mceerr(int code, void __user *, short);
int send_sig_mceerr(int code, void __user *, short, struct task_struct *);

int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
int force_sig_pkuerr(void __user *addr, u32 pkey);
int send_sig_perf(void __user *addr, u32 type, u64 sig_data);

int force_sig_ptrace_errno_trap(int errno, void __user *addr);
int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
			struct task_struct *t);
int force_sig_seccomp(int syscall, int reason, bool force_coredump);

extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
extern void force_sigsegv(int sig);
extern int force_sig_info(struct kernel_siginfo *);
extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
				const struct cred *);
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);
extern void force_fatal_sig(int);
extern void force_exit_sig(int);
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 pid *, enum pid_type);
extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);

static inline void clear_notify_signal(void)
{ … }

/*
 * Returns 'true' if kick_process() is needed to force a transition from
 * user -> kernel to guarantee expedient run of TWA_SIGNAL based task_work.
 */
static inline bool __set_notify_signal(struct task_struct *task)
{ … }

/*
 * Called to break out of interruptible wait loops, and enter the
 * exit_to_user_mode_loop().
 */
static inline void set_notify_signal(struct task_struct *task)
{ … }

static inline int restart_syscall(void)
{ … }

static inline int task_sigpending(struct task_struct *p)
{ … }

static inline int signal_pending(struct task_struct *p)
{ … }

static inline int __fatal_signal_pending(struct task_struct *p)
{ … }

static inline int fatal_signal_pending(struct task_struct *p)
{ … }

static inline int signal_pending_state(unsigned int state, struct task_struct *p)
{ … }

/*
 * This should only be used in fault handlers to decide whether we
 * should stop the current fault routine to handle the signals
 * instead, especially with the case where we've got interrupted with
 * a VM_FAULT_RETRY.
 */
static inline bool fault_signal_pending(vm_fault_t fault_flags,
					struct pt_regs *regs)
{ … }

/*
 * 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(void);
extern void calculate_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 fatal)
{ … }
static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
{ … }

void task_join_group_stop(struct task_struct *task);

#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);
}

static inline void clear_tsk_restore_sigmask(struct task_struct *task)
{
	clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
}

static inline void clear_restore_sigmask(void)
{
	clear_thread_flag(TIF_RESTORE_SIGMASK);
}
static inline bool test_tsk_restore_sigmask(struct task_struct *task)
{
	return test_tsk_thread_flag(task, 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)
{ … }
static inline void clear_tsk_restore_sigmask(struct task_struct *task)
{ … }
static inline void clear_restore_sigmask(void)
{ … }
static inline bool test_restore_sigmask(void)
{ … }
static inline bool test_tsk_restore_sigmask(struct task_struct *task)
{ … }
static inline bool test_and_clear_restore_sigmask(void)
{ … }
#endif

static inline void restore_saved_sigmask(void)
{ … }

extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);

static inline void restore_saved_sigmask_unless(bool interrupted)
{ … }

static inline sigset_t *sigmask_to_save(void)
{ … }

static inline int kill_cad_pid(int sig, int priv)
{ … }

/* These can be the second arg to send_sig_info/send_group_sig_info.  */
#define SEND_SIG_NOINFO …
#define SEND_SIG_PRIV …

static inline int __on_sig_stack(unsigned long sp)
{ … }

/*
 * True if we are on the alternate signal stack.
 */
static inline int on_sig_stack(unsigned long sp)
{ … }

static inline int sas_ss_flags(unsigned long sp)
{ … }

static inline void sas_ss_reset(struct task_struct *p)
{ … }

static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig)
{ … }

extern void __cleanup_sighand(struct sighand_struct *);
extern void flush_itimer_signals(void);

#define tasklist_empty() …

#define next_task(p) …

#define for_each_process(p) …

extern bool current_is_single_threaded(void);

/*
 * Without tasklist/siglock it is only rcu-safe if g can't exit/exec,
 * otherwise next_thread(t) will never reach g after list_del_rcu(g).
 */
#define while_each_thread(g, t) …

#define for_other_threads(p, t) …

#define __for_each_thread(signal, t) …

#define for_each_thread(p, t) …

/* Careful: this is a double loop, 'break' won't work as expected. */
#define for_each_process_thread(p, t) …

proc_visitor;
void walk_process_tree(struct task_struct *top, proc_visitor, void *);

static inline
struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
{ … }

static inline struct pid *task_tgid(struct task_struct *task)
{ … }

/*
 * Without tasklist or RCU lock it is not safe to dereference
 * the result of task_pgrp/task_session even if task == current,
 * we can race with another thread doing sys_setsid/sys_setpgid.
 */
static inline struct pid *task_pgrp(struct task_struct *task)
{ … }

static inline struct pid *task_session(struct task_struct *task)
{ … }

static inline int get_nr_threads(struct task_struct *task)
{ … }

static inline bool thread_group_leader(struct task_struct *p)
{ … }

static inline
bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
{ … }

/*
 * returns NULL if p is the last thread in the thread group
 */
static inline struct task_struct *__next_thread(struct task_struct *p)
{ … }

static inline struct task_struct *next_thread(struct task_struct *p)
{ … }

static inline int thread_group_empty(struct task_struct *p)
{ … }

#define delay_group_leader(p) …

extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
							unsigned long *flags);

static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
						       unsigned long *flags)
{ … }

static inline void unlock_task_sighand(struct task_struct *task,
						unsigned long *flags)
{ … }

#ifdef CONFIG_LOCKDEP
extern void lockdep_assert_task_sighand_held(struct task_struct *task);
#else
static inline void lockdep_assert_task_sighand_held(struct task_struct *task) { }
#endif

static inline unsigned long task_rlimit(const struct task_struct *task,
		unsigned int limit)
{ … }

static inline unsigned long task_rlimit_max(const struct task_struct *task,
		unsigned int limit)
{ … }

static inline unsigned long rlimit(unsigned int limit)
{ … }

static inline unsigned long rlimit_max(unsigned int limit)
{ … }

#endif /* _LINUX_SCHED_SIGNAL_H */