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/* 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 {
spinlock_t siglock;
refcount_t count;
wait_queue_head_t signalfd_wqh;
struct k_sigaction action[_NSIG];
};
/*
* 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.
*
* 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;
};
struct multiprocess_signals {
sigset_t signal;
struct hlist_node node;
};
struct core_thread {
struct task_struct *task;
struct core_thread *next;
};
struct core_state {
atomic_t nr_threads;
struct core_thread dumper;
struct completion startup;
};
/*
* 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 {
refcount_t sigcnt;
atomic_t live;
int nr_threads;
int quick_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;
/* For collecting multiprocess signals during fork */
struct hlist_head multiprocess;
/* thread group exit support */
int group_exit_code;
/* notify group_exec_task when notify_count is less or equal to 0 */
int notify_count;
struct task_struct *group_exec_task;
/* thread group stop support, overloads group_exit_code too */
int group_stop_count;
unsigned int flags; /* see SIGNAL_* flags below */
struct core_state *core_state; /* coredumping support */
/*
* 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 */
unsigned int next_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;
#endif
/* Empty if CONFIG_POSIX_TIMERS=n */
struct posix_cputimers posix_cputimers;
/* PID/PID hash table linkage. */
struct pid *pids[PIDTYPE_MAX];
#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)
* Deprecated do not use in new code.
* Use exec_update_lock instead.
*/
struct rw_semaphore exec_update_lock; /* Held while task_struct is
* being updated during exec,
* and may have inconsistent
* permissions.
*/
} __randomize_layout;
/*
* 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 */
/*
* 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);
sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | 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(struct task_struct *task, sigset_t *mask,
kernel_siginfo_t *info, enum pid_type *type);
static inline int kernel_dequeue_signal(void)
{
struct task_struct *task = current;
kernel_siginfo_t __info;
enum pid_type __type;
int ret;
spin_lock_irq(&task->sighand->siglock);
ret = dequeue_signal(task, &task->blocked, &__info, &__type);
spin_unlock_irq(&task->sighand->siglock);
return ret;
}
static inline void kernel_signal_stop(void)
{
spin_lock_irq(¤t->sighand->siglock);
if (current->jobctl & JOBCTL_STOP_DEQUEUED) {
current->jobctl |= JOBCTL_STOPPED;
set_special_state(TASK_STOPPED);
}
spin_unlock_irq(¤t->sighand->siglock);
schedule();
}
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)
{
clear_thread_flag(TIF_NOTIFY_SIGNAL);
smp_mb__after_atomic();
}
/*
* 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)
{
return !test_and_set_tsk_thread_flag(task, TIF_NOTIFY_SIGNAL) &&
!wake_up_state(task, TASK_INTERRUPTIBLE);
}
/*
* 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)
{
if (__set_notify_signal(task))
kick_process(task);
}
static inline int restart_syscall(void)
{
set_tsk_thread_flag(current, TIF_SIGPENDING);
return -ERESTARTNOINTR;
}
static inline int task_sigpending(struct task_struct *p)
{
return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
}
static inline int signal_pending(struct task_struct *p)
{
/*
* TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
* behavior in terms of ensuring that we break out of wait loops
* so that notify signal callbacks can be processed.
*/
if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
return 1;
return task_sigpending(p);
}
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 task_sigpending(p) && __fatal_signal_pending(p);
}
static inline int signal_pending_state(unsigned int 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);
}
/*
* 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)
{
return unlikely((fault_flags & VM_FAULT_RETRY) &&
(fatal_signal_pending(current) ||
(user_mode(regs) && signal_pending(current))));
}
/*
* 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)
{
unsigned int state = 0;
if (fatal && !(t->jobctl & JOBCTL_PTRACE_FROZEN)) {
t->jobctl &= ~(JOBCTL_STOPPED | JOBCTL_TRACED);
state = TASK_WAKEKILL | __TASK_TRACED;
}
signal_wake_up_state(t, state);
}
static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
{
unsigned int state = 0;
if (resume) {
t->jobctl &= ~JOBCTL_TRACED;
state = __TASK_TRACED;
}
signal_wake_up_state(t, state);
}
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)
{
current->restore_sigmask = true;
}
static inline void clear_tsk_restore_sigmask(struct task_struct *task)
{
task->restore_sigmask = false;
}
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_tsk_restore_sigmask(struct task_struct *task)
{
return task->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(¤t->saved_sigmask);
}
extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
static inline void restore_saved_sigmask_unless(bool interrupted)
{
if (interrupted)
WARN_ON(!signal_pending(current));
else
restore_saved_sigmask();
}
static inline sigset_t *sigmask_to_save(void)
{
sigset_t *res = ¤t->blocked;
if (unlikely(test_restore_sigmask()))
res = ¤t->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 kernel_siginfo *) 0)
#define SEND_SIG_PRIV ((struct kernel_siginfo *) 1)
static inline int __on_sig_stack(unsigned long sp)
{
#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
}
/*
* 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;
return __on_sig_stack(sp);
}
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);
/*
* 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) \
while ((t = next_thread(t)) != g)
#define for_other_threads(p, t) \
for (t = p; (t = next_thread(t)) != p; )
#define __for_each_thread(signal, t) \
list_for_each_entry_rcu(t, &(signal)->thread_head, thread_node, \
lockdep_is_held(&tasklist_lock))
#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
struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
{
struct pid *pid;
if (type == PIDTYPE_PID)
pid = task_pid(task);
else
pid = task->signal->pids[type];
return pid;
}
static inline struct pid *task_tgid(struct task_struct *task)
{
return task->signal->pids[PIDTYPE_TGID];
}
/*
* 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)
{
return task->signal->pids[PIDTYPE_PGID];
}
static inline struct pid *task_session(struct task_struct *task)
{
return task->signal->pids[PIDTYPE_SID];
}
static inline int get_nr_threads(struct task_struct *task)
{
return task->signal->nr_threads;
}
static inline bool thread_group_leader(struct task_struct *p)
{
return p->exit_signal >= 0;
}
static inline
bool same_thread_group(struct task_struct *p1, struct task_struct *p2)
{
return p1->signal == p2->signal;
}
/*
* returns NULL if p is the last thread in the thread group
*/
static inline struct task_struct *__next_thread(struct task_struct *p)
{
return list_next_or_null_rcu(&p->signal->thread_head,
&p->thread_node,
struct task_struct,
thread_node);
}
static inline struct task_struct *next_thread(struct task_struct *p)
{
return __next_thread(p) ?: p->group_leader;
}
static inline int thread_group_empty(struct task_struct *p)
{
return thread_group_leader(p) &&
list_is_last(&p->thread_node, &p->signal->thread_head);
}
#define delay_group_leader(p) \
(thread_group_leader(p) && !thread_group_empty(p))
extern bool thread_group_exited(struct pid *pid);
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)
{
struct sighand_struct *ret;
ret = __lock_task_sighand(task, flags);
(void)__cond_lock(&task->sighand->siglock, ret);
return ret;
}
static inline void unlock_task_sighand(struct task_struct *task,
unsigned long *flags)
{
spin_unlock_irqrestore(&task->sighand->siglock, *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)
{
return READ_ONCE(task->signal->rlim[limit].rlim_cur);
}
static inline unsigned long task_rlimit_max(const struct task_struct *task,
unsigned int limit)
{
return READ_ONCE(task->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 */