v4.19.13 snapshot.
diff --git a/kernel/signal.c b/kernel/signal.c
new file mode 100644
index 0000000..edc28af
--- /dev/null
+++ b/kernel/signal.c
@@ -0,0 +1,4017 @@
+/*
+ * linux/kernel/signal.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
+ *
+ * 2003-06-02 Jim Houston - Concurrent Computer Corp.
+ * Changes to use preallocated sigqueue structures
+ * to allow signals to be sent reliably.
+ */
+
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/user.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task.h>
+#include <linux/sched/task_stack.h>
+#include <linux/sched/cputime.h>
+#include <linux/fs.h>
+#include <linux/tty.h>
+#include <linux/binfmts.h>
+#include <linux/coredump.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/ptrace.h>
+#include <linux/signal.h>
+#include <linux/signalfd.h>
+#include <linux/ratelimit.h>
+#include <linux/tracehook.h>
+#include <linux/capability.h>
+#include <linux/freezer.h>
+#include <linux/pid_namespace.h>
+#include <linux/nsproxy.h>
+#include <linux/user_namespace.h>
+#include <linux/uprobes.h>
+#include <linux/compat.h>
+#include <linux/cn_proc.h>
+#include <linux/compiler.h>
+#include <linux/posix-timers.h>
+#include <linux/livepatch.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/signal.h>
+
+#include <asm/param.h>
+#include <linux/uaccess.h>
+#include <asm/unistd.h>
+#include <asm/siginfo.h>
+#include <asm/cacheflush.h>
+#include "audit.h" /* audit_signal_info() */
+
+/*
+ * SLAB caches for signal bits.
+ */
+
+static struct kmem_cache *sigqueue_cachep;
+
+int print_fatal_signals __read_mostly;
+
+static void __user *sig_handler(struct task_struct *t, int sig)
+{
+ return t->sighand->action[sig - 1].sa.sa_handler;
+}
+
+static inline bool sig_handler_ignored(void __user *handler, int sig)
+{
+ /* Is it explicitly or implicitly ignored? */
+ return handler == SIG_IGN ||
+ (handler == SIG_DFL && sig_kernel_ignore(sig));
+}
+
+static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
+{
+ void __user *handler;
+
+ handler = sig_handler(t, sig);
+
+ if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
+ handler == SIG_DFL && !(force && sig_kernel_only(sig)))
+ return true;
+
+ return sig_handler_ignored(handler, sig);
+}
+
+static bool sig_ignored(struct task_struct *t, int sig, bool force)
+{
+ /*
+ * Blocked signals are never ignored, since the
+ * signal handler may change by the time it is
+ * unblocked.
+ */
+ if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
+ return false;
+
+ /*
+ * Tracers may want to know about even ignored signal unless it
+ * is SIGKILL which can't be reported anyway but can be ignored
+ * by SIGNAL_UNKILLABLE task.
+ */
+ if (t->ptrace && sig != SIGKILL)
+ return false;
+
+ return sig_task_ignored(t, sig, force);
+}
+
+/*
+ * Re-calculate pending state from the set of locally pending
+ * signals, globally pending signals, and blocked signals.
+ */
+static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
+{
+ unsigned long ready;
+ long i;
+
+ switch (_NSIG_WORDS) {
+ default:
+ for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
+ ready |= signal->sig[i] &~ blocked->sig[i];
+ break;
+
+ case 4: ready = signal->sig[3] &~ blocked->sig[3];
+ ready |= signal->sig[2] &~ blocked->sig[2];
+ ready |= signal->sig[1] &~ blocked->sig[1];
+ ready |= signal->sig[0] &~ blocked->sig[0];
+ break;
+
+ case 2: ready = signal->sig[1] &~ blocked->sig[1];
+ ready |= signal->sig[0] &~ blocked->sig[0];
+ break;
+
+ case 1: ready = signal->sig[0] &~ blocked->sig[0];
+ }
+ return ready != 0;
+}
+
+#define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
+
+static bool recalc_sigpending_tsk(struct task_struct *t)
+{
+ if ((t->jobctl & JOBCTL_PENDING_MASK) ||
+ PENDING(&t->pending, &t->blocked) ||
+ PENDING(&t->signal->shared_pending, &t->blocked)) {
+ set_tsk_thread_flag(t, TIF_SIGPENDING);
+ return true;
+ }
+
+ /*
+ * We must never clear the flag in another thread, or in current
+ * when it's possible the current syscall is returning -ERESTART*.
+ * So we don't clear it here, and only callers who know they should do.
+ */
+ return false;
+}
+
+/*
+ * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
+ * This is superfluous when called on current, the wakeup is a harmless no-op.
+ */
+void recalc_sigpending_and_wake(struct task_struct *t)
+{
+ if (recalc_sigpending_tsk(t))
+ signal_wake_up(t, 0);
+}
+
+void recalc_sigpending(void)
+{
+ if (!recalc_sigpending_tsk(current) && !freezing(current) &&
+ !klp_patch_pending(current))
+ clear_thread_flag(TIF_SIGPENDING);
+
+}
+
+void calculate_sigpending(void)
+{
+ /* Have any signals or users of TIF_SIGPENDING been delayed
+ * until after fork?
+ */
+ spin_lock_irq(¤t->sighand->siglock);
+ set_tsk_thread_flag(current, TIF_SIGPENDING);
+ recalc_sigpending();
+ spin_unlock_irq(¤t->sighand->siglock);
+}
+
+/* Given the mask, find the first available signal that should be serviced. */
+
+#define SYNCHRONOUS_MASK \
+ (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
+ sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
+
+int next_signal(struct sigpending *pending, sigset_t *mask)
+{
+ unsigned long i, *s, *m, x;
+ int sig = 0;
+
+ s = pending->signal.sig;
+ m = mask->sig;
+
+ /*
+ * Handle the first word specially: it contains the
+ * synchronous signals that need to be dequeued first.
+ */
+ x = *s &~ *m;
+ if (x) {
+ if (x & SYNCHRONOUS_MASK)
+ x &= SYNCHRONOUS_MASK;
+ sig = ffz(~x) + 1;
+ return sig;
+ }
+
+ switch (_NSIG_WORDS) {
+ default:
+ for (i = 1; i < _NSIG_WORDS; ++i) {
+ x = *++s &~ *++m;
+ if (!x)
+ continue;
+ sig = ffz(~x) + i*_NSIG_BPW + 1;
+ break;
+ }
+ break;
+
+ case 2:
+ x = s[1] &~ m[1];
+ if (!x)
+ break;
+ sig = ffz(~x) + _NSIG_BPW + 1;
+ break;
+
+ case 1:
+ /* Nothing to do */
+ break;
+ }
+
+ return sig;
+}
+
+static inline void print_dropped_signal(int sig)
+{
+ static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
+
+ if (!print_fatal_signals)
+ return;
+
+ if (!__ratelimit(&ratelimit_state))
+ return;
+
+ pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
+ current->comm, current->pid, sig);
+}
+
+/**
+ * task_set_jobctl_pending - set jobctl pending bits
+ * @task: target task
+ * @mask: pending bits to set
+ *
+ * Clear @mask from @task->jobctl. @mask must be subset of
+ * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
+ * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
+ * cleared. If @task is already being killed or exiting, this function
+ * becomes noop.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ *
+ * RETURNS:
+ * %true if @mask is set, %false if made noop because @task was dying.
+ */
+bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
+{
+ BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
+ JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
+ BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
+
+ if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
+ return false;
+
+ if (mask & JOBCTL_STOP_SIGMASK)
+ task->jobctl &= ~JOBCTL_STOP_SIGMASK;
+
+ task->jobctl |= mask;
+ return true;
+}
+
+/**
+ * task_clear_jobctl_trapping - clear jobctl trapping bit
+ * @task: target task
+ *
+ * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
+ * Clear it and wake up the ptracer. Note that we don't need any further
+ * locking. @task->siglock guarantees that @task->parent points to the
+ * ptracer.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+void task_clear_jobctl_trapping(struct task_struct *task)
+{
+ if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
+ task->jobctl &= ~JOBCTL_TRAPPING;
+ smp_mb(); /* advised by wake_up_bit() */
+ wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
+ }
+}
+
+/**
+ * task_clear_jobctl_pending - clear jobctl pending bits
+ * @task: target task
+ * @mask: pending bits to clear
+ *
+ * Clear @mask from @task->jobctl. @mask must be subset of
+ * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
+ * STOP bits are cleared together.
+ *
+ * If clearing of @mask leaves no stop or trap pending, this function calls
+ * task_clear_jobctl_trapping().
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
+{
+ BUG_ON(mask & ~JOBCTL_PENDING_MASK);
+
+ if (mask & JOBCTL_STOP_PENDING)
+ mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
+
+ task->jobctl &= ~mask;
+
+ if (!(task->jobctl & JOBCTL_PENDING_MASK))
+ task_clear_jobctl_trapping(task);
+}
+
+/**
+ * task_participate_group_stop - participate in a group stop
+ * @task: task participating in a group stop
+ *
+ * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
+ * Group stop states are cleared and the group stop count is consumed if
+ * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
+ * stop, the appropriate %SIGNAL_* flags are set.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ *
+ * RETURNS:
+ * %true if group stop completion should be notified to the parent, %false
+ * otherwise.
+ */
+static bool task_participate_group_stop(struct task_struct *task)
+{
+ struct signal_struct *sig = task->signal;
+ bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
+
+ WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
+
+ task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
+
+ if (!consume)
+ return false;
+
+ if (!WARN_ON_ONCE(sig->group_stop_count == 0))
+ sig->group_stop_count--;
+
+ /*
+ * Tell the caller to notify completion iff we are entering into a
+ * fresh group stop. Read comment in do_signal_stop() for details.
+ */
+ if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
+ signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
+ return true;
+ }
+ return false;
+}
+
+void task_join_group_stop(struct task_struct *task)
+{
+ /* Have the new thread join an on-going signal group stop */
+ unsigned long jobctl = current->jobctl;
+ if (jobctl & JOBCTL_STOP_PENDING) {
+ struct signal_struct *sig = current->signal;
+ unsigned long signr = jobctl & JOBCTL_STOP_SIGMASK;
+ unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
+ if (task_set_jobctl_pending(task, signr | gstop)) {
+ sig->group_stop_count++;
+ }
+ }
+}
+
+/*
+ * allocate a new signal queue record
+ * - this may be called without locks if and only if t == current, otherwise an
+ * appropriate lock must be held to stop the target task from exiting
+ */
+static struct sigqueue *
+__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
+{
+ struct sigqueue *q = NULL;
+ struct user_struct *user;
+
+ /*
+ * Protect access to @t credentials. This can go away when all
+ * callers hold rcu read lock.
+ */
+ rcu_read_lock();
+ user = get_uid(__task_cred(t)->user);
+ atomic_inc(&user->sigpending);
+ rcu_read_unlock();
+
+ if (override_rlimit ||
+ atomic_read(&user->sigpending) <=
+ task_rlimit(t, RLIMIT_SIGPENDING)) {
+ q = kmem_cache_alloc(sigqueue_cachep, flags);
+ } else {
+ print_dropped_signal(sig);
+ }
+
+ if (unlikely(q == NULL)) {
+ atomic_dec(&user->sigpending);
+ free_uid(user);
+ } else {
+ INIT_LIST_HEAD(&q->list);
+ q->flags = 0;
+ q->user = user;
+ }
+
+ return q;
+}
+
+static void __sigqueue_free(struct sigqueue *q)
+{
+ if (q->flags & SIGQUEUE_PREALLOC)
+ return;
+ atomic_dec(&q->user->sigpending);
+ free_uid(q->user);
+ kmem_cache_free(sigqueue_cachep, q);
+}
+
+void flush_sigqueue(struct sigpending *queue)
+{
+ struct sigqueue *q;
+
+ sigemptyset(&queue->signal);
+ while (!list_empty(&queue->list)) {
+ q = list_entry(queue->list.next, struct sigqueue , list);
+ list_del_init(&q->list);
+ __sigqueue_free(q);
+ }
+}
+
+/*
+ * Flush all pending signals for this kthread.
+ */
+void flush_signals(struct task_struct *t)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&t->sighand->siglock, flags);
+ clear_tsk_thread_flag(t, TIF_SIGPENDING);
+ flush_sigqueue(&t->pending);
+ flush_sigqueue(&t->signal->shared_pending);
+ spin_unlock_irqrestore(&t->sighand->siglock, flags);
+}
+
+#ifdef CONFIG_POSIX_TIMERS
+static void __flush_itimer_signals(struct sigpending *pending)
+{
+ sigset_t signal, retain;
+ struct sigqueue *q, *n;
+
+ signal = pending->signal;
+ sigemptyset(&retain);
+
+ list_for_each_entry_safe(q, n, &pending->list, list) {
+ int sig = q->info.si_signo;
+
+ if (likely(q->info.si_code != SI_TIMER)) {
+ sigaddset(&retain, sig);
+ } else {
+ sigdelset(&signal, sig);
+ list_del_init(&q->list);
+ __sigqueue_free(q);
+ }
+ }
+
+ sigorsets(&pending->signal, &signal, &retain);
+}
+
+void flush_itimer_signals(void)
+{
+ struct task_struct *tsk = current;
+ unsigned long flags;
+
+ spin_lock_irqsave(&tsk->sighand->siglock, flags);
+ __flush_itimer_signals(&tsk->pending);
+ __flush_itimer_signals(&tsk->signal->shared_pending);
+ spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+}
+#endif
+
+void ignore_signals(struct task_struct *t)
+{
+ int i;
+
+ for (i = 0; i < _NSIG; ++i)
+ t->sighand->action[i].sa.sa_handler = SIG_IGN;
+
+ flush_signals(t);
+}
+
+/*
+ * Flush all handlers for a task.
+ */
+
+void
+flush_signal_handlers(struct task_struct *t, int force_default)
+{
+ int i;
+ struct k_sigaction *ka = &t->sighand->action[0];
+ for (i = _NSIG ; i != 0 ; i--) {
+ if (force_default || ka->sa.sa_handler != SIG_IGN)
+ ka->sa.sa_handler = SIG_DFL;
+ ka->sa.sa_flags = 0;
+#ifdef __ARCH_HAS_SA_RESTORER
+ ka->sa.sa_restorer = NULL;
+#endif
+ sigemptyset(&ka->sa.sa_mask);
+ ka++;
+ }
+}
+
+bool unhandled_signal(struct task_struct *tsk, int sig)
+{
+ void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
+ if (is_global_init(tsk))
+ return true;
+
+ if (handler != SIG_IGN && handler != SIG_DFL)
+ return false;
+
+ /* if ptraced, let the tracer determine */
+ return !tsk->ptrace;
+}
+
+static void collect_signal(int sig, struct sigpending *list, siginfo_t *info,
+ bool *resched_timer)
+{
+ struct sigqueue *q, *first = NULL;
+
+ /*
+ * Collect the siginfo appropriate to this signal. Check if
+ * there is another siginfo for the same signal.
+ */
+ list_for_each_entry(q, &list->list, list) {
+ if (q->info.si_signo == sig) {
+ if (first)
+ goto still_pending;
+ first = q;
+ }
+ }
+
+ sigdelset(&list->signal, sig);
+
+ if (first) {
+still_pending:
+ list_del_init(&first->list);
+ copy_siginfo(info, &first->info);
+
+ *resched_timer =
+ (first->flags & SIGQUEUE_PREALLOC) &&
+ (info->si_code == SI_TIMER) &&
+ (info->si_sys_private);
+
+ __sigqueue_free(first);
+ } else {
+ /*
+ * Ok, it wasn't in the queue. This must be
+ * a fast-pathed signal or we must have been
+ * out of queue space. So zero out the info.
+ */
+ clear_siginfo(info);
+ info->si_signo = sig;
+ info->si_errno = 0;
+ info->si_code = SI_USER;
+ info->si_pid = 0;
+ info->si_uid = 0;
+ }
+}
+
+static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
+ siginfo_t *info, bool *resched_timer)
+{
+ int sig = next_signal(pending, mask);
+
+ if (sig)
+ collect_signal(sig, pending, info, resched_timer);
+ return sig;
+}
+
+/*
+ * Dequeue a signal and return the element to the caller, which is
+ * expected to free it.
+ *
+ * All callers have to hold the siglock.
+ */
+int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
+{
+ bool resched_timer = false;
+ int signr;
+
+ /* We only dequeue private signals from ourselves, we don't let
+ * signalfd steal them
+ */
+ signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
+ if (!signr) {
+ signr = __dequeue_signal(&tsk->signal->shared_pending,
+ mask, info, &resched_timer);
+#ifdef CONFIG_POSIX_TIMERS
+ /*
+ * itimer signal ?
+ *
+ * itimers are process shared and we restart periodic
+ * itimers in the signal delivery path to prevent DoS
+ * attacks in the high resolution timer case. This is
+ * compliant with the old way of self-restarting
+ * itimers, as the SIGALRM is a legacy signal and only
+ * queued once. Changing the restart behaviour to
+ * restart the timer in the signal dequeue path is
+ * reducing the timer noise on heavy loaded !highres
+ * systems too.
+ */
+ if (unlikely(signr == SIGALRM)) {
+ struct hrtimer *tmr = &tsk->signal->real_timer;
+
+ if (!hrtimer_is_queued(tmr) &&
+ tsk->signal->it_real_incr != 0) {
+ hrtimer_forward(tmr, tmr->base->get_time(),
+ tsk->signal->it_real_incr);
+ hrtimer_restart(tmr);
+ }
+ }
+#endif
+ }
+
+ recalc_sigpending();
+ if (!signr)
+ return 0;
+
+ if (unlikely(sig_kernel_stop(signr))) {
+ /*
+ * Set a marker that we have dequeued a stop signal. Our
+ * caller might release the siglock and then the pending
+ * stop signal it is about to process is no longer in the
+ * pending bitmasks, but must still be cleared by a SIGCONT
+ * (and overruled by a SIGKILL). So those cases clear this
+ * shared flag after we've set it. Note that this flag may
+ * remain set after the signal we return is ignored or
+ * handled. That doesn't matter because its only purpose
+ * is to alert stop-signal processing code when another
+ * processor has come along and cleared the flag.
+ */
+ current->jobctl |= JOBCTL_STOP_DEQUEUED;
+ }
+#ifdef CONFIG_POSIX_TIMERS
+ if (resched_timer) {
+ /*
+ * Release the siglock to ensure proper locking order
+ * of timer locks outside of siglocks. Note, we leave
+ * irqs disabled here, since the posix-timers code is
+ * about to disable them again anyway.
+ */
+ spin_unlock(&tsk->sighand->siglock);
+ posixtimer_rearm(info);
+ spin_lock(&tsk->sighand->siglock);
+
+ /* Don't expose the si_sys_private value to userspace */
+ info->si_sys_private = 0;
+ }
+#endif
+ return signr;
+}
+
+/*
+ * Tell a process that it has a new active signal..
+ *
+ * NOTE! we rely on the previous spin_lock to
+ * lock interrupts for us! We can only be called with
+ * "siglock" held, and the local interrupt must
+ * have been disabled when that got acquired!
+ *
+ * No need to set need_resched since signal event passing
+ * goes through ->blocked
+ */
+void signal_wake_up_state(struct task_struct *t, unsigned int state)
+{
+ set_tsk_thread_flag(t, TIF_SIGPENDING);
+ /*
+ * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
+ * case. We don't check t->state here because there is a race with it
+ * executing another processor and just now entering stopped state.
+ * By using wake_up_state, we ensure the process will wake up and
+ * handle its death signal.
+ */
+ if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
+ kick_process(t);
+}
+
+/*
+ * Remove signals in mask from the pending set and queue.
+ * Returns 1 if any signals were found.
+ *
+ * All callers must be holding the siglock.
+ */
+static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
+{
+ struct sigqueue *q, *n;
+ sigset_t m;
+
+ sigandsets(&m, mask, &s->signal);
+ if (sigisemptyset(&m))
+ return;
+
+ sigandnsets(&s->signal, &s->signal, mask);
+ list_for_each_entry_safe(q, n, &s->list, list) {
+ if (sigismember(mask, q->info.si_signo)) {
+ list_del_init(&q->list);
+ __sigqueue_free(q);
+ }
+ }
+}
+
+static inline int is_si_special(const struct siginfo *info)
+{
+ return info <= SEND_SIG_FORCED;
+}
+
+static inline bool si_fromuser(const struct siginfo *info)
+{
+ return info == SEND_SIG_NOINFO ||
+ (!is_si_special(info) && SI_FROMUSER(info));
+}
+
+/*
+ * called with RCU read lock from check_kill_permission()
+ */
+static bool kill_ok_by_cred(struct task_struct *t)
+{
+ const struct cred *cred = current_cred();
+ const struct cred *tcred = __task_cred(t);
+
+ return uid_eq(cred->euid, tcred->suid) ||
+ uid_eq(cred->euid, tcred->uid) ||
+ uid_eq(cred->uid, tcred->suid) ||
+ uid_eq(cred->uid, tcred->uid) ||
+ ns_capable(tcred->user_ns, CAP_KILL);
+}
+
+/*
+ * Bad permissions for sending the signal
+ * - the caller must hold the RCU read lock
+ */
+static int check_kill_permission(int sig, struct siginfo *info,
+ struct task_struct *t)
+{
+ struct pid *sid;
+ int error;
+
+ if (!valid_signal(sig))
+ return -EINVAL;
+
+ if (!si_fromuser(info))
+ return 0;
+
+ error = audit_signal_info(sig, t); /* Let audit system see the signal */
+ if (error)
+ return error;
+
+ if (!same_thread_group(current, t) &&
+ !kill_ok_by_cred(t)) {
+ switch (sig) {
+ case SIGCONT:
+ sid = task_session(t);
+ /*
+ * We don't return the error if sid == NULL. The
+ * task was unhashed, the caller must notice this.
+ */
+ if (!sid || sid == task_session(current))
+ break;
+ default:
+ return -EPERM;
+ }
+ }
+
+ return security_task_kill(t, info, sig, NULL);
+}
+
+/**
+ * ptrace_trap_notify - schedule trap to notify ptracer
+ * @t: tracee wanting to notify tracer
+ *
+ * This function schedules sticky ptrace trap which is cleared on the next
+ * TRAP_STOP to notify ptracer of an event. @t must have been seized by
+ * ptracer.
+ *
+ * If @t is running, STOP trap will be taken. If trapped for STOP and
+ * ptracer is listening for events, tracee is woken up so that it can
+ * re-trap for the new event. If trapped otherwise, STOP trap will be
+ * eventually taken without returning to userland after the existing traps
+ * are finished by PTRACE_CONT.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+static void ptrace_trap_notify(struct task_struct *t)
+{
+ WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
+ assert_spin_locked(&t->sighand->siglock);
+
+ task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
+ ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
+}
+
+/*
+ * Handle magic process-wide effects of stop/continue signals. Unlike
+ * the signal actions, these happen immediately at signal-generation
+ * time regardless of blocking, ignoring, or handling. This does the
+ * actual continuing for SIGCONT, but not the actual stopping for stop
+ * signals. The process stop is done as a signal action for SIG_DFL.
+ *
+ * Returns true if the signal should be actually delivered, otherwise
+ * it should be dropped.
+ */
+static bool prepare_signal(int sig, struct task_struct *p, bool force)
+{
+ struct signal_struct *signal = p->signal;
+ struct task_struct *t;
+ sigset_t flush;
+
+ if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
+ if (!(signal->flags & SIGNAL_GROUP_EXIT))
+ return sig == SIGKILL;
+ /*
+ * The process is in the middle of dying, nothing to do.
+ */
+ } else if (sig_kernel_stop(sig)) {
+ /*
+ * This is a stop signal. Remove SIGCONT from all queues.
+ */
+ siginitset(&flush, sigmask(SIGCONT));
+ flush_sigqueue_mask(&flush, &signal->shared_pending);
+ for_each_thread(p, t)
+ flush_sigqueue_mask(&flush, &t->pending);
+ } else if (sig == SIGCONT) {
+ unsigned int why;
+ /*
+ * Remove all stop signals from all queues, wake all threads.
+ */
+ siginitset(&flush, SIG_KERNEL_STOP_MASK);
+ flush_sigqueue_mask(&flush, &signal->shared_pending);
+ for_each_thread(p, t) {
+ flush_sigqueue_mask(&flush, &t->pending);
+ task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
+ if (likely(!(t->ptrace & PT_SEIZED)))
+ wake_up_state(t, __TASK_STOPPED);
+ else
+ ptrace_trap_notify(t);
+ }
+
+ /*
+ * Notify the parent with CLD_CONTINUED if we were stopped.
+ *
+ * If we were in the middle of a group stop, we pretend it
+ * was already finished, and then continued. Since SIGCHLD
+ * doesn't queue we report only CLD_STOPPED, as if the next
+ * CLD_CONTINUED was dropped.
+ */
+ why = 0;
+ if (signal->flags & SIGNAL_STOP_STOPPED)
+ why |= SIGNAL_CLD_CONTINUED;
+ else if (signal->group_stop_count)
+ why |= SIGNAL_CLD_STOPPED;
+
+ if (why) {
+ /*
+ * The first thread which returns from do_signal_stop()
+ * will take ->siglock, notice SIGNAL_CLD_MASK, and
+ * notify its parent. See get_signal_to_deliver().
+ */
+ signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
+ signal->group_stop_count = 0;
+ signal->group_exit_code = 0;
+ }
+ }
+
+ return !sig_ignored(p, sig, force);
+}
+
+/*
+ * Test if P wants to take SIG. After we've checked all threads with this,
+ * it's equivalent to finding no threads not blocking SIG. Any threads not
+ * blocking SIG were ruled out because they are not running and already
+ * have pending signals. Such threads will dequeue from the shared queue
+ * as soon as they're available, so putting the signal on the shared queue
+ * will be equivalent to sending it to one such thread.
+ */
+static inline bool wants_signal(int sig, struct task_struct *p)
+{
+ if (sigismember(&p->blocked, sig))
+ return false;
+
+ if (p->flags & PF_EXITING)
+ return false;
+
+ if (sig == SIGKILL)
+ return true;
+
+ if (task_is_stopped_or_traced(p))
+ return false;
+
+ return task_curr(p) || !signal_pending(p);
+}
+
+static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
+{
+ struct signal_struct *signal = p->signal;
+ struct task_struct *t;
+
+ /*
+ * Now find a thread we can wake up to take the signal off the queue.
+ *
+ * If the main thread wants the signal, it gets first crack.
+ * Probably the least surprising to the average bear.
+ */
+ if (wants_signal(sig, p))
+ t = p;
+ else if ((type == PIDTYPE_PID) || thread_group_empty(p))
+ /*
+ * There is just one thread and it does not need to be woken.
+ * It will dequeue unblocked signals before it runs again.
+ */
+ return;
+ else {
+ /*
+ * Otherwise try to find a suitable thread.
+ */
+ t = signal->curr_target;
+ while (!wants_signal(sig, t)) {
+ t = next_thread(t);
+ if (t == signal->curr_target)
+ /*
+ * No thread needs to be woken.
+ * Any eligible threads will see
+ * the signal in the queue soon.
+ */
+ return;
+ }
+ signal->curr_target = t;
+ }
+
+ /*
+ * Found a killable thread. If the signal will be fatal,
+ * then start taking the whole group down immediately.
+ */
+ if (sig_fatal(p, sig) &&
+ !(signal->flags & SIGNAL_GROUP_EXIT) &&
+ !sigismember(&t->real_blocked, sig) &&
+ (sig == SIGKILL || !p->ptrace)) {
+ /*
+ * This signal will be fatal to the whole group.
+ */
+ if (!sig_kernel_coredump(sig)) {
+ /*
+ * Start a group exit and wake everybody up.
+ * This way we don't have other threads
+ * running and doing things after a slower
+ * thread has the fatal signal pending.
+ */
+ signal->flags = SIGNAL_GROUP_EXIT;
+ signal->group_exit_code = sig;
+ signal->group_stop_count = 0;
+ t = p;
+ do {
+ task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
+ sigaddset(&t->pending.signal, SIGKILL);
+ signal_wake_up(t, 1);
+ } while_each_thread(p, t);
+ return;
+ }
+ }
+
+ /*
+ * The signal is already in the shared-pending queue.
+ * Tell the chosen thread to wake up and dequeue it.
+ */
+ signal_wake_up(t, sig == SIGKILL);
+ return;
+}
+
+static inline bool legacy_queue(struct sigpending *signals, int sig)
+{
+ return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
+}
+
+#ifdef CONFIG_USER_NS
+static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
+{
+ if (current_user_ns() == task_cred_xxx(t, user_ns))
+ return;
+
+ if (SI_FROMKERNEL(info))
+ return;
+
+ rcu_read_lock();
+ info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns),
+ make_kuid(current_user_ns(), info->si_uid));
+ rcu_read_unlock();
+}
+#else
+static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
+{
+ return;
+}
+#endif
+
+static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
+ enum pid_type type, int from_ancestor_ns)
+{
+ struct sigpending *pending;
+ struct sigqueue *q;
+ int override_rlimit;
+ int ret = 0, result;
+
+ assert_spin_locked(&t->sighand->siglock);
+
+ result = TRACE_SIGNAL_IGNORED;
+ if (!prepare_signal(sig, t,
+ from_ancestor_ns || (info == SEND_SIG_PRIV) || (info == SEND_SIG_FORCED)))
+ goto ret;
+
+ pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
+ /*
+ * Short-circuit ignored signals and support queuing
+ * exactly one non-rt signal, so that we can get more
+ * detailed information about the cause of the signal.
+ */
+ result = TRACE_SIGNAL_ALREADY_PENDING;
+ if (legacy_queue(pending, sig))
+ goto ret;
+
+ result = TRACE_SIGNAL_DELIVERED;
+ /*
+ * fast-pathed signals for kernel-internal things like SIGSTOP
+ * or SIGKILL.
+ */
+ if (info == SEND_SIG_FORCED)
+ goto out_set;
+
+ /*
+ * Real-time signals must be queued if sent by sigqueue, or
+ * some other real-time mechanism. It is implementation
+ * defined whether kill() does so. We attempt to do so, on
+ * the principle of least surprise, but since kill is not
+ * allowed to fail with EAGAIN when low on memory we just
+ * make sure at least one signal gets delivered and don't
+ * pass on the info struct.
+ */
+ if (sig < SIGRTMIN)
+ override_rlimit = (is_si_special(info) || info->si_code >= 0);
+ else
+ override_rlimit = 0;
+
+ q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
+ if (q) {
+ list_add_tail(&q->list, &pending->list);
+ switch ((unsigned long) info) {
+ case (unsigned long) SEND_SIG_NOINFO:
+ clear_siginfo(&q->info);
+ q->info.si_signo = sig;
+ q->info.si_errno = 0;
+ q->info.si_code = SI_USER;
+ q->info.si_pid = task_tgid_nr_ns(current,
+ task_active_pid_ns(t));
+ q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
+ break;
+ case (unsigned long) SEND_SIG_PRIV:
+ clear_siginfo(&q->info);
+ q->info.si_signo = sig;
+ q->info.si_errno = 0;
+ q->info.si_code = SI_KERNEL;
+ q->info.si_pid = 0;
+ q->info.si_uid = 0;
+ break;
+ default:
+ copy_siginfo(&q->info, info);
+ if (from_ancestor_ns)
+ q->info.si_pid = 0;
+ break;
+ }
+
+ userns_fixup_signal_uid(&q->info, t);
+
+ } else if (!is_si_special(info)) {
+ if (sig >= SIGRTMIN && info->si_code != SI_USER) {
+ /*
+ * Queue overflow, abort. We may abort if the
+ * signal was rt and sent by user using something
+ * other than kill().
+ */
+ result = TRACE_SIGNAL_OVERFLOW_FAIL;
+ ret = -EAGAIN;
+ goto ret;
+ } else {
+ /*
+ * This is a silent loss of information. We still
+ * send the signal, but the *info bits are lost.
+ */
+ result = TRACE_SIGNAL_LOSE_INFO;
+ }
+ }
+
+out_set:
+ signalfd_notify(t, sig);
+ sigaddset(&pending->signal, sig);
+
+ /* Let multiprocess signals appear after on-going forks */
+ if (type > PIDTYPE_TGID) {
+ struct multiprocess_signals *delayed;
+ hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
+ sigset_t *signal = &delayed->signal;
+ /* Can't queue both a stop and a continue signal */
+ if (sig == SIGCONT)
+ sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
+ else if (sig_kernel_stop(sig))
+ sigdelset(signal, SIGCONT);
+ sigaddset(signal, sig);
+ }
+ }
+
+ complete_signal(sig, t, type);
+ret:
+ trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
+ return ret;
+}
+
+static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
+ enum pid_type type)
+{
+ int from_ancestor_ns = 0;
+
+#ifdef CONFIG_PID_NS
+ from_ancestor_ns = si_fromuser(info) &&
+ !task_pid_nr_ns(current, task_active_pid_ns(t));
+#endif
+
+ return __send_signal(sig, info, t, type, from_ancestor_ns);
+}
+
+static void print_fatal_signal(int signr)
+{
+ struct pt_regs *regs = signal_pt_regs();
+ pr_info("potentially unexpected fatal signal %d.\n", signr);
+
+#if defined(__i386__) && !defined(__arch_um__)
+ pr_info("code at %08lx: ", regs->ip);
+ {
+ int i;
+ for (i = 0; i < 16; i++) {
+ unsigned char insn;
+
+ if (get_user(insn, (unsigned char *)(regs->ip + i)))
+ break;
+ pr_cont("%02x ", insn);
+ }
+ }
+ pr_cont("\n");
+#endif
+ preempt_disable();
+ show_regs(regs);
+ preempt_enable();
+}
+
+static int __init setup_print_fatal_signals(char *str)
+{
+ get_option (&str, &print_fatal_signals);
+
+ return 1;
+}
+
+__setup("print-fatal-signals=", setup_print_fatal_signals);
+
+int
+__group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+{
+ return send_signal(sig, info, p, PIDTYPE_TGID);
+}
+
+static int
+specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+{
+ return send_signal(sig, info, t, PIDTYPE_PID);
+}
+
+int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
+ enum pid_type type)
+{
+ unsigned long flags;
+ int ret = -ESRCH;
+
+ if (lock_task_sighand(p, &flags)) {
+ ret = send_signal(sig, info, p, type);
+ unlock_task_sighand(p, &flags);
+ }
+
+ return ret;
+}
+
+/*
+ * Force a signal that the process can't ignore: if necessary
+ * we unblock the signal and change any SIG_IGN to SIG_DFL.
+ *
+ * Note: If we unblock the signal, we always reset it to SIG_DFL,
+ * since we do not want to have a signal handler that was blocked
+ * be invoked when user space had explicitly blocked it.
+ *
+ * We don't want to have recursive SIGSEGV's etc, for example,
+ * that is why we also clear SIGNAL_UNKILLABLE.
+ */
+int
+force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+{
+ unsigned long int flags;
+ int ret, blocked, ignored;
+ struct k_sigaction *action;
+
+ spin_lock_irqsave(&t->sighand->siglock, flags);
+ action = &t->sighand->action[sig-1];
+ ignored = action->sa.sa_handler == SIG_IGN;
+ blocked = sigismember(&t->blocked, sig);
+ if (blocked || ignored) {
+ action->sa.sa_handler = SIG_DFL;
+ if (blocked) {
+ sigdelset(&t->blocked, sig);
+ recalc_sigpending_and_wake(t);
+ }
+ }
+ /*
+ * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
+ * debugging to leave init killable.
+ */
+ if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
+ t->signal->flags &= ~SIGNAL_UNKILLABLE;
+ ret = specific_send_sig_info(sig, info, t);
+ spin_unlock_irqrestore(&t->sighand->siglock, flags);
+
+ return ret;
+}
+
+/*
+ * Nuke all other threads in the group.
+ */
+int zap_other_threads(struct task_struct *p)
+{
+ struct task_struct *t = p;
+ int count = 0;
+
+ p->signal->group_stop_count = 0;
+
+ while_each_thread(p, t) {
+ task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
+ count++;
+
+ /* Don't bother with already dead threads */
+ if (t->exit_state)
+ continue;
+ sigaddset(&t->pending.signal, SIGKILL);
+ signal_wake_up(t, 1);
+ }
+
+ return count;
+}
+
+struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
+ unsigned long *flags)
+{
+ struct sighand_struct *sighand;
+
+ rcu_read_lock();
+ for (;;) {
+ sighand = rcu_dereference(tsk->sighand);
+ if (unlikely(sighand == NULL))
+ break;
+
+ /*
+ * This sighand can be already freed and even reused, but
+ * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
+ * initializes ->siglock: this slab can't go away, it has
+ * the same object type, ->siglock can't be reinitialized.
+ *
+ * We need to ensure that tsk->sighand is still the same
+ * after we take the lock, we can race with de_thread() or
+ * __exit_signal(). In the latter case the next iteration
+ * must see ->sighand == NULL.
+ */
+ spin_lock_irqsave(&sighand->siglock, *flags);
+ if (likely(sighand == tsk->sighand))
+ break;
+ spin_unlock_irqrestore(&sighand->siglock, *flags);
+ }
+ rcu_read_unlock();
+
+ return sighand;
+}
+
+/*
+ * send signal info to all the members of a group
+ */
+int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
+ enum pid_type type)
+{
+ int ret;
+
+ rcu_read_lock();
+ ret = check_kill_permission(sig, info, p);
+ rcu_read_unlock();
+
+ if (!ret && sig)
+ ret = do_send_sig_info(sig, info, p, type);
+
+ return ret;
+}
+
+/*
+ * __kill_pgrp_info() sends a signal to a process group: this is what the tty
+ * control characters do (^C, ^Z etc)
+ * - the caller must hold at least a readlock on tasklist_lock
+ */
+int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
+{
+ struct task_struct *p = NULL;
+ int retval, success;
+
+ success = 0;
+ retval = -ESRCH;
+ do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+ int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
+ success |= !err;
+ retval = err;
+ } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+ return success ? 0 : retval;
+}
+
+int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
+{
+ int error = -ESRCH;
+ struct task_struct *p;
+
+ for (;;) {
+ rcu_read_lock();
+ p = pid_task(pid, PIDTYPE_PID);
+ if (p)
+ error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
+ rcu_read_unlock();
+ if (likely(!p || error != -ESRCH))
+ return error;
+
+ /*
+ * The task was unhashed in between, try again. If it
+ * is dead, pid_task() will return NULL, if we race with
+ * de_thread() it will find the new leader.
+ */
+ }
+}
+
+static int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+{
+ int error;
+ rcu_read_lock();
+ error = kill_pid_info(sig, info, find_vpid(pid));
+ rcu_read_unlock();
+ return error;
+}
+
+static inline bool kill_as_cred_perm(const struct cred *cred,
+ struct task_struct *target)
+{
+ const struct cred *pcred = __task_cred(target);
+
+ return uid_eq(cred->euid, pcred->suid) ||
+ uid_eq(cred->euid, pcred->uid) ||
+ uid_eq(cred->uid, pcred->suid) ||
+ uid_eq(cred->uid, pcred->uid);
+}
+
+/* like kill_pid_info(), but doesn't use uid/euid of "current" */
+int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
+ const struct cred *cred)
+{
+ int ret = -EINVAL;
+ struct task_struct *p;
+ unsigned long flags;
+
+ if (!valid_signal(sig))
+ return ret;
+
+ rcu_read_lock();
+ p = pid_task(pid, PIDTYPE_PID);
+ if (!p) {
+ ret = -ESRCH;
+ goto out_unlock;
+ }
+ if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
+ ret = -EPERM;
+ goto out_unlock;
+ }
+ ret = security_task_kill(p, info, sig, cred);
+ if (ret)
+ goto out_unlock;
+
+ if (sig) {
+ if (lock_task_sighand(p, &flags)) {
+ ret = __send_signal(sig, info, p, PIDTYPE_TGID, 0);
+ unlock_task_sighand(p, &flags);
+ } else
+ ret = -ESRCH;
+ }
+out_unlock:
+ rcu_read_unlock();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
+
+/*
+ * kill_something_info() interprets pid in interesting ways just like kill(2).
+ *
+ * POSIX specifies that kill(-1,sig) is unspecified, but what we have
+ * is probably wrong. Should make it like BSD or SYSV.
+ */
+
+static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
+{
+ int ret;
+
+ if (pid > 0) {
+ rcu_read_lock();
+ ret = kill_pid_info(sig, info, find_vpid(pid));
+ rcu_read_unlock();
+ return ret;
+ }
+
+ /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
+ if (pid == INT_MIN)
+ return -ESRCH;
+
+ read_lock(&tasklist_lock);
+ if (pid != -1) {
+ ret = __kill_pgrp_info(sig, info,
+ pid ? find_vpid(-pid) : task_pgrp(current));
+ } else {
+ int retval = 0, count = 0;
+ struct task_struct * p;
+
+ for_each_process(p) {
+ if (task_pid_vnr(p) > 1 &&
+ !same_thread_group(p, current)) {
+ int err = group_send_sig_info(sig, info, p,
+ PIDTYPE_MAX);
+ ++count;
+ if (err != -EPERM)
+ retval = err;
+ }
+ }
+ ret = count ? retval : -ESRCH;
+ }
+ read_unlock(&tasklist_lock);
+
+ return ret;
+}
+
+/*
+ * These are for backward compatibility with the rest of the kernel source.
+ */
+
+int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+{
+ /*
+ * Make sure legacy kernel users don't send in bad values
+ * (normal paths check this in check_kill_permission).
+ */
+ if (!valid_signal(sig))
+ return -EINVAL;
+
+ return do_send_sig_info(sig, info, p, PIDTYPE_PID);
+}
+
+#define __si_special(priv) \
+ ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
+
+int
+send_sig(int sig, struct task_struct *p, int priv)
+{
+ return send_sig_info(sig, __si_special(priv), p);
+}
+
+void force_sig(int sig, struct task_struct *p)
+{
+ force_sig_info(sig, SEND_SIG_PRIV, p);
+}
+
+/*
+ * When things go south during signal handling, we
+ * will force a SIGSEGV. And if the signal that caused
+ * the problem was already a SIGSEGV, we'll want to
+ * make sure we don't even try to deliver the signal..
+ */
+void force_sigsegv(int sig, struct task_struct *p)
+{
+ if (sig == SIGSEGV) {
+ unsigned long flags;
+ spin_lock_irqsave(&p->sighand->siglock, flags);
+ p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
+ spin_unlock_irqrestore(&p->sighand->siglock, flags);
+ }
+ force_sig(SIGSEGV, p);
+}
+
+int force_sig_fault(int sig, int code, void __user *addr
+ ___ARCH_SI_TRAPNO(int trapno)
+ ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
+ , struct task_struct *t)
+{
+ struct siginfo info;
+
+ clear_siginfo(&info);
+ info.si_signo = sig;
+ info.si_errno = 0;
+ info.si_code = code;
+ info.si_addr = addr;
+#ifdef __ARCH_SI_TRAPNO
+ info.si_trapno = trapno;
+#endif
+#ifdef __ia64__
+ info.si_imm = imm;
+ info.si_flags = flags;
+ info.si_isr = isr;
+#endif
+ return force_sig_info(info.si_signo, &info, t);
+}
+
+int send_sig_fault(int sig, int code, void __user *addr
+ ___ARCH_SI_TRAPNO(int trapno)
+ ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
+ , struct task_struct *t)
+{
+ struct siginfo info;
+
+ clear_siginfo(&info);
+ info.si_signo = sig;
+ info.si_errno = 0;
+ info.si_code = code;
+ info.si_addr = addr;
+#ifdef __ARCH_SI_TRAPNO
+ info.si_trapno = trapno;
+#endif
+#ifdef __ia64__
+ info.si_imm = imm;
+ info.si_flags = flags;
+ info.si_isr = isr;
+#endif
+ return send_sig_info(info.si_signo, &info, t);
+}
+
+int force_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
+{
+ struct siginfo info;
+
+ WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
+ clear_siginfo(&info);
+ info.si_signo = SIGBUS;
+ info.si_errno = 0;
+ info.si_code = code;
+ info.si_addr = addr;
+ info.si_addr_lsb = lsb;
+ return force_sig_info(info.si_signo, &info, t);
+}
+
+int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
+{
+ struct siginfo info;
+
+ WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
+ clear_siginfo(&info);
+ info.si_signo = SIGBUS;
+ info.si_errno = 0;
+ info.si_code = code;
+ info.si_addr = addr;
+ info.si_addr_lsb = lsb;
+ return send_sig_info(info.si_signo, &info, t);
+}
+EXPORT_SYMBOL(send_sig_mceerr);
+
+int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
+{
+ struct siginfo info;
+
+ clear_siginfo(&info);
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ info.si_code = SEGV_BNDERR;
+ info.si_addr = addr;
+ info.si_lower = lower;
+ info.si_upper = upper;
+ return force_sig_info(info.si_signo, &info, current);
+}
+
+#ifdef SEGV_PKUERR
+int force_sig_pkuerr(void __user *addr, u32 pkey)
+{
+ struct siginfo info;
+
+ clear_siginfo(&info);
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ info.si_code = SEGV_PKUERR;
+ info.si_addr = addr;
+ info.si_pkey = pkey;
+ return force_sig_info(info.si_signo, &info, current);
+}
+#endif
+
+/* For the crazy architectures that include trap information in
+ * the errno field, instead of an actual errno value.
+ */
+int force_sig_ptrace_errno_trap(int errno, void __user *addr)
+{
+ struct siginfo info;
+
+ clear_siginfo(&info);
+ info.si_signo = SIGTRAP;
+ info.si_errno = errno;
+ info.si_code = TRAP_HWBKPT;
+ info.si_addr = addr;
+ return force_sig_info(info.si_signo, &info, current);
+}
+
+int kill_pgrp(struct pid *pid, int sig, int priv)
+{
+ int ret;
+
+ read_lock(&tasklist_lock);
+ ret = __kill_pgrp_info(sig, __si_special(priv), pid);
+ read_unlock(&tasklist_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL(kill_pgrp);
+
+int kill_pid(struct pid *pid, int sig, int priv)
+{
+ return kill_pid_info(sig, __si_special(priv), pid);
+}
+EXPORT_SYMBOL(kill_pid);
+
+/*
+ * These functions support sending signals using preallocated sigqueue
+ * structures. This is needed "because realtime applications cannot
+ * afford to lose notifications of asynchronous events, like timer
+ * expirations or I/O completions". In the case of POSIX Timers
+ * we allocate the sigqueue structure from the timer_create. If this
+ * allocation fails we are able to report the failure to the application
+ * with an EAGAIN error.
+ */
+struct sigqueue *sigqueue_alloc(void)
+{
+ struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
+
+ if (q)
+ q->flags |= SIGQUEUE_PREALLOC;
+
+ return q;
+}
+
+void sigqueue_free(struct sigqueue *q)
+{
+ unsigned long flags;
+ spinlock_t *lock = ¤t->sighand->siglock;
+
+ BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+ /*
+ * We must hold ->siglock while testing q->list
+ * to serialize with collect_signal() or with
+ * __exit_signal()->flush_sigqueue().
+ */
+ spin_lock_irqsave(lock, flags);
+ q->flags &= ~SIGQUEUE_PREALLOC;
+ /*
+ * If it is queued it will be freed when dequeued,
+ * like the "regular" sigqueue.
+ */
+ if (!list_empty(&q->list))
+ q = NULL;
+ spin_unlock_irqrestore(lock, flags);
+
+ if (q)
+ __sigqueue_free(q);
+}
+
+int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
+{
+ int sig = q->info.si_signo;
+ struct sigpending *pending;
+ struct task_struct *t;
+ unsigned long flags;
+ int ret, result;
+
+ BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+
+ ret = -1;
+ rcu_read_lock();
+ t = pid_task(pid, type);
+ if (!t || !likely(lock_task_sighand(t, &flags)))
+ goto ret;
+
+ ret = 1; /* the signal is ignored */
+ result = TRACE_SIGNAL_IGNORED;
+ if (!prepare_signal(sig, t, false))
+ goto out;
+
+ ret = 0;
+ if (unlikely(!list_empty(&q->list))) {
+ /*
+ * If an SI_TIMER entry is already queue just increment
+ * the overrun count.
+ */
+ BUG_ON(q->info.si_code != SI_TIMER);
+ q->info.si_overrun++;
+ result = TRACE_SIGNAL_ALREADY_PENDING;
+ goto out;
+ }
+ q->info.si_overrun = 0;
+
+ signalfd_notify(t, sig);
+ pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
+ list_add_tail(&q->list, &pending->list);
+ sigaddset(&pending->signal, sig);
+ complete_signal(sig, t, type);
+ result = TRACE_SIGNAL_DELIVERED;
+out:
+ trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
+ unlock_task_sighand(t, &flags);
+ret:
+ rcu_read_unlock();
+ return ret;
+}
+
+/*
+ * Let a parent know about the death of a child.
+ * For a stopped/continued status change, use do_notify_parent_cldstop instead.
+ *
+ * Returns true if our parent ignored us and so we've switched to
+ * self-reaping.
+ */
+bool do_notify_parent(struct task_struct *tsk, int sig)
+{
+ struct siginfo info;
+ unsigned long flags;
+ struct sighand_struct *psig;
+ bool autoreap = false;
+ u64 utime, stime;
+
+ BUG_ON(sig == -1);
+
+ /* do_notify_parent_cldstop should have been called instead. */
+ BUG_ON(task_is_stopped_or_traced(tsk));
+
+ BUG_ON(!tsk->ptrace &&
+ (tsk->group_leader != tsk || !thread_group_empty(tsk)));
+
+ if (sig != SIGCHLD) {
+ /*
+ * This is only possible if parent == real_parent.
+ * Check if it has changed security domain.
+ */
+ if (tsk->parent_exec_id != tsk->parent->self_exec_id)
+ sig = SIGCHLD;
+ }
+
+ clear_siginfo(&info);
+ info.si_signo = sig;
+ info.si_errno = 0;
+ /*
+ * We are under tasklist_lock here so our parent is tied to
+ * us and cannot change.
+ *
+ * task_active_pid_ns will always return the same pid namespace
+ * until a task passes through release_task.
+ *
+ * write_lock() currently calls preempt_disable() which is the
+ * same as rcu_read_lock(), but according to Oleg, this is not
+ * correct to rely on this
+ */
+ rcu_read_lock();
+ info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
+ info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
+ task_uid(tsk));
+ rcu_read_unlock();
+
+ task_cputime(tsk, &utime, &stime);
+ info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
+ info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
+
+ info.si_status = tsk->exit_code & 0x7f;
+ if (tsk->exit_code & 0x80)
+ info.si_code = CLD_DUMPED;
+ else if (tsk->exit_code & 0x7f)
+ info.si_code = CLD_KILLED;
+ else {
+ info.si_code = CLD_EXITED;
+ info.si_status = tsk->exit_code >> 8;
+ }
+
+ psig = tsk->parent->sighand;
+ spin_lock_irqsave(&psig->siglock, flags);
+ if (!tsk->ptrace && sig == SIGCHLD &&
+ (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
+ (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
+ /*
+ * We are exiting and our parent doesn't care. POSIX.1
+ * defines special semantics for setting SIGCHLD to SIG_IGN
+ * or setting the SA_NOCLDWAIT flag: we should be reaped
+ * automatically and not left for our parent's wait4 call.
+ * Rather than having the parent do it as a magic kind of
+ * signal handler, we just set this to tell do_exit that we
+ * can be cleaned up without becoming a zombie. Note that
+ * we still call __wake_up_parent in this case, because a
+ * blocked sys_wait4 might now return -ECHILD.
+ *
+ * Whether we send SIGCHLD or not for SA_NOCLDWAIT
+ * is implementation-defined: we do (if you don't want
+ * it, just use SIG_IGN instead).
+ */
+ autoreap = true;
+ if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
+ sig = 0;
+ }
+ if (valid_signal(sig) && sig)
+ __group_send_sig_info(sig, &info, tsk->parent);
+ __wake_up_parent(tsk, tsk->parent);
+ spin_unlock_irqrestore(&psig->siglock, flags);
+
+ return autoreap;
+}
+
+/**
+ * do_notify_parent_cldstop - notify parent of stopped/continued state change
+ * @tsk: task reporting the state change
+ * @for_ptracer: the notification is for ptracer
+ * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
+ *
+ * Notify @tsk's parent that the stopped/continued state has changed. If
+ * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
+ * If %true, @tsk reports to @tsk->parent which should be the ptracer.
+ *
+ * CONTEXT:
+ * Must be called with tasklist_lock at least read locked.
+ */
+static void do_notify_parent_cldstop(struct task_struct *tsk,
+ bool for_ptracer, int why)
+{
+ struct siginfo info;
+ unsigned long flags;
+ struct task_struct *parent;
+ struct sighand_struct *sighand;
+ u64 utime, stime;
+
+ if (for_ptracer) {
+ parent = tsk->parent;
+ } else {
+ tsk = tsk->group_leader;
+ parent = tsk->real_parent;
+ }
+
+ clear_siginfo(&info);
+ info.si_signo = SIGCHLD;
+ info.si_errno = 0;
+ /*
+ * see comment in do_notify_parent() about the following 4 lines
+ */
+ rcu_read_lock();
+ info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
+ info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
+ rcu_read_unlock();
+
+ task_cputime(tsk, &utime, &stime);
+ info.si_utime = nsec_to_clock_t(utime);
+ info.si_stime = nsec_to_clock_t(stime);
+
+ info.si_code = why;
+ switch (why) {
+ case CLD_CONTINUED:
+ info.si_status = SIGCONT;
+ break;
+ case CLD_STOPPED:
+ info.si_status = tsk->signal->group_exit_code & 0x7f;
+ break;
+ case CLD_TRAPPED:
+ info.si_status = tsk->exit_code & 0x7f;
+ break;
+ default:
+ BUG();
+ }
+
+ sighand = parent->sighand;
+ spin_lock_irqsave(&sighand->siglock, flags);
+ if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
+ !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
+ __group_send_sig_info(SIGCHLD, &info, parent);
+ /*
+ * Even if SIGCHLD is not generated, we must wake up wait4 calls.
+ */
+ __wake_up_parent(tsk, parent);
+ spin_unlock_irqrestore(&sighand->siglock, flags);
+}
+
+static inline bool may_ptrace_stop(void)
+{
+ if (!likely(current->ptrace))
+ return false;
+ /*
+ * Are we in the middle of do_coredump?
+ * If so and our tracer is also part of the coredump stopping
+ * is a deadlock situation, and pointless because our tracer
+ * is dead so don't allow us to stop.
+ * If SIGKILL was already sent before the caller unlocked
+ * ->siglock we must see ->core_state != NULL. Otherwise it
+ * is safe to enter schedule().
+ *
+ * This is almost outdated, a task with the pending SIGKILL can't
+ * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
+ * after SIGKILL was already dequeued.
+ */
+ if (unlikely(current->mm->core_state) &&
+ unlikely(current->mm == current->parent->mm))
+ return false;
+
+ return true;
+}
+
+/*
+ * Return non-zero if there is a SIGKILL that should be waking us up.
+ * Called with the siglock held.
+ */
+static bool sigkill_pending(struct task_struct *tsk)
+{
+ return sigismember(&tsk->pending.signal, SIGKILL) ||
+ sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
+}
+
+/*
+ * This must be called with current->sighand->siglock held.
+ *
+ * This should be the path for all ptrace stops.
+ * We always set current->last_siginfo while stopped here.
+ * That makes it a way to test a stopped process for
+ * being ptrace-stopped vs being job-control-stopped.
+ *
+ * If we actually decide not to stop at all because the tracer
+ * is gone, we keep current->exit_code unless clear_code.
+ */
+static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
+ __releases(¤t->sighand->siglock)
+ __acquires(¤t->sighand->siglock)
+{
+ bool gstop_done = false;
+
+ if (arch_ptrace_stop_needed(exit_code, info)) {
+ /*
+ * The arch code has something special to do before a
+ * ptrace stop. This is allowed to block, e.g. for faults
+ * on user stack pages. We can't keep the siglock while
+ * calling arch_ptrace_stop, so we must release it now.
+ * To preserve proper semantics, we must do this before
+ * any signal bookkeeping like checking group_stop_count.
+ * Meanwhile, a SIGKILL could come in before we retake the
+ * siglock. That must prevent us from sleeping in TASK_TRACED.
+ * So after regaining the lock, we must check for SIGKILL.
+ */
+ spin_unlock_irq(¤t->sighand->siglock);
+ arch_ptrace_stop(exit_code, info);
+ spin_lock_irq(¤t->sighand->siglock);
+ if (sigkill_pending(current))
+ return;
+ }
+
+ set_special_state(TASK_TRACED);
+
+ /*
+ * We're committing to trapping. TRACED should be visible before
+ * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
+ * Also, transition to TRACED and updates to ->jobctl should be
+ * atomic with respect to siglock and should be done after the arch
+ * hook as siglock is released and regrabbed across it.
+ *
+ * TRACER TRACEE
+ *
+ * ptrace_attach()
+ * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
+ * do_wait()
+ * set_current_state() smp_wmb();
+ * ptrace_do_wait()
+ * wait_task_stopped()
+ * task_stopped_code()
+ * [L] task_is_traced() [S] task_clear_jobctl_trapping();
+ */
+ smp_wmb();
+
+ current->last_siginfo = info;
+ current->exit_code = exit_code;
+
+ /*
+ * If @why is CLD_STOPPED, we're trapping to participate in a group
+ * stop. Do the bookkeeping. Note that if SIGCONT was delievered
+ * across siglock relocks since INTERRUPT was scheduled, PENDING
+ * could be clear now. We act as if SIGCONT is received after
+ * TASK_TRACED is entered - ignore it.
+ */
+ if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
+ gstop_done = task_participate_group_stop(current);
+
+ /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
+ task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
+ if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
+ task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
+
+ /* entering a trap, clear TRAPPING */
+ task_clear_jobctl_trapping(current);
+
+ spin_unlock_irq(¤t->sighand->siglock);
+ read_lock(&tasklist_lock);
+ if (may_ptrace_stop()) {
+ /*
+ * Notify parents of the stop.
+ *
+ * While ptraced, there are two parents - the ptracer and
+ * the real_parent of the group_leader. The ptracer should
+ * know about every stop while the real parent is only
+ * interested in the completion of group stop. The states
+ * for the two don't interact with each other. Notify
+ * separately unless they're gonna be duplicates.
+ */
+ do_notify_parent_cldstop(current, true, why);
+ if (gstop_done && ptrace_reparented(current))
+ do_notify_parent_cldstop(current, false, why);
+
+ /*
+ * Don't want to allow preemption here, because
+ * sys_ptrace() needs this task to be inactive.
+ *
+ * XXX: implement read_unlock_no_resched().
+ */
+ preempt_disable();
+ read_unlock(&tasklist_lock);
+ preempt_enable_no_resched();
+ freezable_schedule();
+ } else {
+ /*
+ * By the time we got the lock, our tracer went away.
+ * Don't drop the lock yet, another tracer may come.
+ *
+ * If @gstop_done, the ptracer went away between group stop
+ * completion and here. During detach, it would have set
+ * JOBCTL_STOP_PENDING on us and we'll re-enter
+ * TASK_STOPPED in do_signal_stop() on return, so notifying
+ * the real parent of the group stop completion is enough.
+ */
+ if (gstop_done)
+ do_notify_parent_cldstop(current, false, why);
+
+ /* tasklist protects us from ptrace_freeze_traced() */
+ __set_current_state(TASK_RUNNING);
+ if (clear_code)
+ current->exit_code = 0;
+ read_unlock(&tasklist_lock);
+ }
+
+ /*
+ * We are back. Now reacquire the siglock before touching
+ * last_siginfo, so that we are sure to have synchronized with
+ * any signal-sending on another CPU that wants to examine it.
+ */
+ spin_lock_irq(¤t->sighand->siglock);
+ current->last_siginfo = NULL;
+
+ /* LISTENING can be set only during STOP traps, clear it */
+ current->jobctl &= ~JOBCTL_LISTENING;
+
+ /*
+ * Queued signals ignored us while we were stopped for tracing.
+ * So check for any that we should take before resuming user mode.
+ * This sets TIF_SIGPENDING, but never clears it.
+ */
+ recalc_sigpending_tsk(current);
+}
+
+static void ptrace_do_notify(int signr, int exit_code, int why)
+{
+ siginfo_t info;
+
+ clear_siginfo(&info);
+ info.si_signo = signr;
+ info.si_code = exit_code;
+ info.si_pid = task_pid_vnr(current);
+ info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
+
+ /* Let the debugger run. */
+ ptrace_stop(exit_code, why, 1, &info);
+}
+
+void ptrace_notify(int exit_code)
+{
+ BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
+ if (unlikely(current->task_works))
+ task_work_run();
+
+ spin_lock_irq(¤t->sighand->siglock);
+ ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
+ spin_unlock_irq(¤t->sighand->siglock);
+}
+
+/**
+ * do_signal_stop - handle group stop for SIGSTOP and other stop signals
+ * @signr: signr causing group stop if initiating
+ *
+ * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
+ * and participate in it. If already set, participate in the existing
+ * group stop. If participated in a group stop (and thus slept), %true is
+ * returned with siglock released.
+ *
+ * If ptraced, this function doesn't handle stop itself. Instead,
+ * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
+ * untouched. The caller must ensure that INTERRUPT trap handling takes
+ * places afterwards.
+ *
+ * CONTEXT:
+ * Must be called with @current->sighand->siglock held, which is released
+ * on %true return.
+ *
+ * RETURNS:
+ * %false if group stop is already cancelled or ptrace trap is scheduled.
+ * %true if participated in group stop.
+ */
+static bool do_signal_stop(int signr)
+ __releases(¤t->sighand->siglock)
+{
+ struct signal_struct *sig = current->signal;
+
+ if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
+ unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
+ struct task_struct *t;
+
+ /* signr will be recorded in task->jobctl for retries */
+ WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
+
+ if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
+ unlikely(signal_group_exit(sig)))
+ return false;
+ /*
+ * There is no group stop already in progress. We must
+ * initiate one now.
+ *
+ * While ptraced, a task may be resumed while group stop is
+ * still in effect and then receive a stop signal and
+ * initiate another group stop. This deviates from the
+ * usual behavior as two consecutive stop signals can't
+ * cause two group stops when !ptraced. That is why we
+ * also check !task_is_stopped(t) below.
+ *
+ * The condition can be distinguished by testing whether
+ * SIGNAL_STOP_STOPPED is already set. Don't generate
+ * group_exit_code in such case.
+ *
+ * This is not necessary for SIGNAL_STOP_CONTINUED because
+ * an intervening stop signal is required to cause two
+ * continued events regardless of ptrace.
+ */
+ if (!(sig->flags & SIGNAL_STOP_STOPPED))
+ sig->group_exit_code = signr;
+
+ sig->group_stop_count = 0;
+
+ if (task_set_jobctl_pending(current, signr | gstop))
+ sig->group_stop_count++;
+
+ t = current;
+ while_each_thread(current, t) {
+ /*
+ * Setting state to TASK_STOPPED for a group
+ * stop is always done with the siglock held,
+ * so this check has no races.
+ */
+ if (!task_is_stopped(t) &&
+ task_set_jobctl_pending(t, signr | gstop)) {
+ sig->group_stop_count++;
+ if (likely(!(t->ptrace & PT_SEIZED)))
+ signal_wake_up(t, 0);
+ else
+ ptrace_trap_notify(t);
+ }
+ }
+ }
+
+ if (likely(!current->ptrace)) {
+ int notify = 0;
+
+ /*
+ * If there are no other threads in the group, or if there
+ * is a group stop in progress and we are the last to stop,
+ * report to the parent.
+ */
+ if (task_participate_group_stop(current))
+ notify = CLD_STOPPED;
+
+ set_special_state(TASK_STOPPED);
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ /*
+ * Notify the parent of the group stop completion. Because
+ * we're not holding either the siglock or tasklist_lock
+ * here, ptracer may attach inbetween; however, this is for
+ * group stop and should always be delivered to the real
+ * parent of the group leader. The new ptracer will get
+ * its notification when this task transitions into
+ * TASK_TRACED.
+ */
+ if (notify) {
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(current, false, notify);
+ read_unlock(&tasklist_lock);
+ }
+
+ /* Now we don't run again until woken by SIGCONT or SIGKILL */
+ freezable_schedule();
+ return true;
+ } else {
+ /*
+ * While ptraced, group stop is handled by STOP trap.
+ * Schedule it and let the caller deal with it.
+ */
+ task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
+ return false;
+ }
+}
+
+/**
+ * do_jobctl_trap - take care of ptrace jobctl traps
+ *
+ * When PT_SEIZED, it's used for both group stop and explicit
+ * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
+ * accompanying siginfo. If stopped, lower eight bits of exit_code contain
+ * the stop signal; otherwise, %SIGTRAP.
+ *
+ * When !PT_SEIZED, it's used only for group stop trap with stop signal
+ * number as exit_code and no siginfo.
+ *
+ * CONTEXT:
+ * Must be called with @current->sighand->siglock held, which may be
+ * released and re-acquired before returning with intervening sleep.
+ */
+static void do_jobctl_trap(void)
+{
+ struct signal_struct *signal = current->signal;
+ int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
+
+ if (current->ptrace & PT_SEIZED) {
+ if (!signal->group_stop_count &&
+ !(signal->flags & SIGNAL_STOP_STOPPED))
+ signr = SIGTRAP;
+ WARN_ON_ONCE(!signr);
+ ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
+ CLD_STOPPED);
+ } else {
+ WARN_ON_ONCE(!signr);
+ ptrace_stop(signr, CLD_STOPPED, 0, NULL);
+ current->exit_code = 0;
+ }
+}
+
+static int ptrace_signal(int signr, siginfo_t *info)
+{
+ /*
+ * We do not check sig_kernel_stop(signr) but set this marker
+ * unconditionally because we do not know whether debugger will
+ * change signr. This flag has no meaning unless we are going
+ * to stop after return from ptrace_stop(). In this case it will
+ * be checked in do_signal_stop(), we should only stop if it was
+ * not cleared by SIGCONT while we were sleeping. See also the
+ * comment in dequeue_signal().
+ */
+ current->jobctl |= JOBCTL_STOP_DEQUEUED;
+ ptrace_stop(signr, CLD_TRAPPED, 0, info);
+
+ /* We're back. Did the debugger cancel the sig? */
+ signr = current->exit_code;
+ if (signr == 0)
+ return signr;
+
+ current->exit_code = 0;
+
+ /*
+ * Update the siginfo structure if the signal has
+ * changed. If the debugger wanted something
+ * specific in the siginfo structure then it should
+ * have updated *info via PTRACE_SETSIGINFO.
+ */
+ if (signr != info->si_signo) {
+ clear_siginfo(info);
+ info->si_signo = signr;
+ info->si_errno = 0;
+ info->si_code = SI_USER;
+ rcu_read_lock();
+ info->si_pid = task_pid_vnr(current->parent);
+ info->si_uid = from_kuid_munged(current_user_ns(),
+ task_uid(current->parent));
+ rcu_read_unlock();
+ }
+
+ /* If the (new) signal is now blocked, requeue it. */
+ if (sigismember(¤t->blocked, signr)) {
+ specific_send_sig_info(signr, info, current);
+ signr = 0;
+ }
+
+ return signr;
+}
+
+bool get_signal(struct ksignal *ksig)
+{
+ struct sighand_struct *sighand = current->sighand;
+ struct signal_struct *signal = current->signal;
+ int signr;
+
+ if (unlikely(current->task_works))
+ task_work_run();
+
+ if (unlikely(uprobe_deny_signal()))
+ return false;
+
+ /*
+ * Do this once, we can't return to user-mode if freezing() == T.
+ * do_signal_stop() and ptrace_stop() do freezable_schedule() and
+ * thus do not need another check after return.
+ */
+ try_to_freeze();
+
+relock:
+ spin_lock_irq(&sighand->siglock);
+ /*
+ * Every stopped thread goes here after wakeup. Check to see if
+ * we should notify the parent, prepare_signal(SIGCONT) encodes
+ * the CLD_ si_code into SIGNAL_CLD_MASK bits.
+ */
+ if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
+ int why;
+
+ if (signal->flags & SIGNAL_CLD_CONTINUED)
+ why = CLD_CONTINUED;
+ else
+ why = CLD_STOPPED;
+
+ signal->flags &= ~SIGNAL_CLD_MASK;
+
+ spin_unlock_irq(&sighand->siglock);
+
+ /*
+ * Notify the parent that we're continuing. This event is
+ * always per-process and doesn't make whole lot of sense
+ * for ptracers, who shouldn't consume the state via
+ * wait(2) either, but, for backward compatibility, notify
+ * the ptracer of the group leader too unless it's gonna be
+ * a duplicate.
+ */
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(current, false, why);
+
+ if (ptrace_reparented(current->group_leader))
+ do_notify_parent_cldstop(current->group_leader,
+ true, why);
+ read_unlock(&tasklist_lock);
+
+ goto relock;
+ }
+
+ for (;;) {
+ struct k_sigaction *ka;
+
+ if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
+ do_signal_stop(0))
+ goto relock;
+
+ if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
+ do_jobctl_trap();
+ spin_unlock_irq(&sighand->siglock);
+ goto relock;
+ }
+
+ signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
+
+ if (!signr)
+ break; /* will return 0 */
+
+ if (unlikely(current->ptrace) && signr != SIGKILL) {
+ signr = ptrace_signal(signr, &ksig->info);
+ if (!signr)
+ continue;
+ }
+
+ ka = &sighand->action[signr-1];
+
+ /* Trace actually delivered signals. */
+ trace_signal_deliver(signr, &ksig->info, ka);
+
+ if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
+ continue;
+ if (ka->sa.sa_handler != SIG_DFL) {
+ /* Run the handler. */
+ ksig->ka = *ka;
+
+ if (ka->sa.sa_flags & SA_ONESHOT)
+ ka->sa.sa_handler = SIG_DFL;
+
+ break; /* will return non-zero "signr" value */
+ }
+
+ /*
+ * Now we are doing the default action for this signal.
+ */
+ if (sig_kernel_ignore(signr)) /* Default is nothing. */
+ continue;
+
+ /*
+ * Global init gets no signals it doesn't want.
+ * Container-init gets no signals it doesn't want from same
+ * container.
+ *
+ * Note that if global/container-init sees a sig_kernel_only()
+ * signal here, the signal must have been generated internally
+ * or must have come from an ancestor namespace. In either
+ * case, the signal cannot be dropped.
+ */
+ if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
+ !sig_kernel_only(signr))
+ continue;
+
+ if (sig_kernel_stop(signr)) {
+ /*
+ * The default action is to stop all threads in
+ * the thread group. The job control signals
+ * do nothing in an orphaned pgrp, but SIGSTOP
+ * always works. Note that siglock needs to be
+ * dropped during the call to is_orphaned_pgrp()
+ * because of lock ordering with tasklist_lock.
+ * This allows an intervening SIGCONT to be posted.
+ * We need to check for that and bail out if necessary.
+ */
+ if (signr != SIGSTOP) {
+ spin_unlock_irq(&sighand->siglock);
+
+ /* signals can be posted during this window */
+
+ if (is_current_pgrp_orphaned())
+ goto relock;
+
+ spin_lock_irq(&sighand->siglock);
+ }
+
+ if (likely(do_signal_stop(ksig->info.si_signo))) {
+ /* It released the siglock. */
+ goto relock;
+ }
+
+ /*
+ * We didn't actually stop, due to a race
+ * with SIGCONT or something like that.
+ */
+ continue;
+ }
+
+ spin_unlock_irq(&sighand->siglock);
+
+ /*
+ * Anything else is fatal, maybe with a core dump.
+ */
+ current->flags |= PF_SIGNALED;
+
+ if (sig_kernel_coredump(signr)) {
+ if (print_fatal_signals)
+ print_fatal_signal(ksig->info.si_signo);
+ proc_coredump_connector(current);
+ /*
+ * If it was able to dump core, this kills all
+ * other threads in the group and synchronizes with
+ * their demise. If we lost the race with another
+ * thread getting here, it set group_exit_code
+ * first and our do_group_exit call below will use
+ * that value and ignore the one we pass it.
+ */
+ do_coredump(&ksig->info);
+ }
+
+ /*
+ * Death signals, no core dump.
+ */
+ do_group_exit(ksig->info.si_signo);
+ /* NOTREACHED */
+ }
+ spin_unlock_irq(&sighand->siglock);
+
+ ksig->sig = signr;
+ return ksig->sig > 0;
+}
+
+/**
+ * signal_delivered -
+ * @ksig: kernel signal struct
+ * @stepping: nonzero if debugger single-step or block-step in use
+ *
+ * This function should be called when a signal has successfully been
+ * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
+ * is always blocked, and the signal itself is blocked unless %SA_NODEFER
+ * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
+ */
+static void signal_delivered(struct ksignal *ksig, int stepping)
+{
+ sigset_t blocked;
+
+ /* A signal was successfully delivered, and the
+ saved sigmask was stored on the signal frame,
+ and will be restored by sigreturn. So we can
+ simply clear the restore sigmask flag. */
+ clear_restore_sigmask();
+
+ sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
+ if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
+ sigaddset(&blocked, ksig->sig);
+ set_current_blocked(&blocked);
+ tracehook_signal_handler(stepping);
+}
+
+void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
+{
+ if (failed)
+ force_sigsegv(ksig->sig, current);
+ else
+ signal_delivered(ksig, stepping);
+}
+
+/*
+ * It could be that complete_signal() picked us to notify about the
+ * group-wide signal. Other threads should be notified now to take
+ * the shared signals in @which since we will not.
+ */
+static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
+{
+ sigset_t retarget;
+ struct task_struct *t;
+
+ sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
+ if (sigisemptyset(&retarget))
+ return;
+
+ t = tsk;
+ while_each_thread(tsk, t) {
+ if (t->flags & PF_EXITING)
+ continue;
+
+ if (!has_pending_signals(&retarget, &t->blocked))
+ continue;
+ /* Remove the signals this thread can handle. */
+ sigandsets(&retarget, &retarget, &t->blocked);
+
+ if (!signal_pending(t))
+ signal_wake_up(t, 0);
+
+ if (sigisemptyset(&retarget))
+ break;
+ }
+}
+
+void exit_signals(struct task_struct *tsk)
+{
+ int group_stop = 0;
+ sigset_t unblocked;
+
+ /*
+ * @tsk is about to have PF_EXITING set - lock out users which
+ * expect stable threadgroup.
+ */
+ cgroup_threadgroup_change_begin(tsk);
+
+ if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
+ tsk->flags |= PF_EXITING;
+ cgroup_threadgroup_change_end(tsk);
+ return;
+ }
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ /*
+ * From now this task is not visible for group-wide signals,
+ * see wants_signal(), do_signal_stop().
+ */
+ tsk->flags |= PF_EXITING;
+
+ cgroup_threadgroup_change_end(tsk);
+
+ if (!signal_pending(tsk))
+ goto out;
+
+ unblocked = tsk->blocked;
+ signotset(&unblocked);
+ retarget_shared_pending(tsk, &unblocked);
+
+ if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
+ task_participate_group_stop(tsk))
+ group_stop = CLD_STOPPED;
+out:
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ /*
+ * If group stop has completed, deliver the notification. This
+ * should always go to the real parent of the group leader.
+ */
+ if (unlikely(group_stop)) {
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(tsk, false, group_stop);
+ read_unlock(&tasklist_lock);
+ }
+}
+
+EXPORT_SYMBOL(recalc_sigpending);
+EXPORT_SYMBOL_GPL(dequeue_signal);
+EXPORT_SYMBOL(flush_signals);
+EXPORT_SYMBOL(force_sig);
+EXPORT_SYMBOL(send_sig);
+EXPORT_SYMBOL(send_sig_info);
+EXPORT_SYMBOL(sigprocmask);
+
+/*
+ * System call entry points.
+ */
+
+/**
+ * sys_restart_syscall - restart a system call
+ */
+SYSCALL_DEFINE0(restart_syscall)
+{
+ struct restart_block *restart = ¤t->restart_block;
+ return restart->fn(restart);
+}
+
+long do_no_restart_syscall(struct restart_block *param)
+{
+ return -EINTR;
+}
+
+static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
+{
+ if (signal_pending(tsk) && !thread_group_empty(tsk)) {
+ sigset_t newblocked;
+ /* A set of now blocked but previously unblocked signals. */
+ sigandnsets(&newblocked, newset, ¤t->blocked);
+ retarget_shared_pending(tsk, &newblocked);
+ }
+ tsk->blocked = *newset;
+ recalc_sigpending();
+}
+
+/**
+ * set_current_blocked - change current->blocked mask
+ * @newset: new mask
+ *
+ * It is wrong to change ->blocked directly, this helper should be used
+ * to ensure the process can't miss a shared signal we are going to block.
+ */
+void set_current_blocked(sigset_t *newset)
+{
+ sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
+ __set_current_blocked(newset);
+}
+
+void __set_current_blocked(const sigset_t *newset)
+{
+ struct task_struct *tsk = current;
+
+ /*
+ * In case the signal mask hasn't changed, there is nothing we need
+ * to do. The current->blocked shouldn't be modified by other task.
+ */
+ if (sigequalsets(&tsk->blocked, newset))
+ return;
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ __set_task_blocked(tsk, newset);
+ spin_unlock_irq(&tsk->sighand->siglock);
+}
+
+/*
+ * This is also useful for kernel threads that want to temporarily
+ * (or permanently) block certain signals.
+ *
+ * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
+ * interface happily blocks "unblockable" signals like SIGKILL
+ * and friends.
+ */
+int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
+{
+ struct task_struct *tsk = current;
+ sigset_t newset;
+
+ /* Lockless, only current can change ->blocked, never from irq */
+ if (oldset)
+ *oldset = tsk->blocked;
+
+ switch (how) {
+ case SIG_BLOCK:
+ sigorsets(&newset, &tsk->blocked, set);
+ break;
+ case SIG_UNBLOCK:
+ sigandnsets(&newset, &tsk->blocked, set);
+ break;
+ case SIG_SETMASK:
+ newset = *set;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ __set_current_blocked(&newset);
+ return 0;
+}
+
+/**
+ * sys_rt_sigprocmask - change the list of currently blocked signals
+ * @how: whether to add, remove, or set signals
+ * @nset: stores pending signals
+ * @oset: previous value of signal mask if non-null
+ * @sigsetsize: size of sigset_t type
+ */
+SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
+ sigset_t __user *, oset, size_t, sigsetsize)
+{
+ sigset_t old_set, new_set;
+ int error;
+
+ /* XXX: Don't preclude handling different sized sigset_t's. */
+ if (sigsetsize != sizeof(sigset_t))
+ return -EINVAL;
+
+ old_set = current->blocked;
+
+ if (nset) {
+ if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
+ return -EFAULT;
+ sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+ error = sigprocmask(how, &new_set, NULL);
+ if (error)
+ return error;
+ }
+
+ if (oset) {
+ if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
+ compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
+{
+ sigset_t old_set = current->blocked;
+
+ /* XXX: Don't preclude handling different sized sigset_t's. */
+ if (sigsetsize != sizeof(sigset_t))
+ return -EINVAL;
+
+ if (nset) {
+ sigset_t new_set;
+ int error;
+ if (get_compat_sigset(&new_set, nset))
+ return -EFAULT;
+ sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+ error = sigprocmask(how, &new_set, NULL);
+ if (error)
+ return error;
+ }
+ return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
+}
+#endif
+
+static void do_sigpending(sigset_t *set)
+{
+ spin_lock_irq(¤t->sighand->siglock);
+ sigorsets(set, ¤t->pending.signal,
+ ¤t->signal->shared_pending.signal);
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ /* Outside the lock because only this thread touches it. */
+ sigandsets(set, ¤t->blocked, set);
+}
+
+/**
+ * sys_rt_sigpending - examine a pending signal that has been raised
+ * while blocked
+ * @uset: stores pending signals
+ * @sigsetsize: size of sigset_t type or larger
+ */
+SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
+{
+ sigset_t set;
+
+ if (sigsetsize > sizeof(*uset))
+ return -EINVAL;
+
+ do_sigpending(&set);
+
+ if (copy_to_user(uset, &set, sigsetsize))
+ return -EFAULT;
+
+ return 0;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
+ compat_size_t, sigsetsize)
+{
+ sigset_t set;
+
+ if (sigsetsize > sizeof(*uset))
+ return -EINVAL;
+
+ do_sigpending(&set);
+
+ return put_compat_sigset(uset, &set, sigsetsize);
+}
+#endif
+
+enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
+{
+ enum siginfo_layout layout = SIL_KILL;
+ if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
+ static const struct {
+ unsigned char limit, layout;
+ } filter[] = {
+ [SIGILL] = { NSIGILL, SIL_FAULT },
+ [SIGFPE] = { NSIGFPE, SIL_FAULT },
+ [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
+ [SIGBUS] = { NSIGBUS, SIL_FAULT },
+ [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
+#if defined(SIGEMT) && defined(NSIGEMT)
+ [SIGEMT] = { NSIGEMT, SIL_FAULT },
+#endif
+ [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
+ [SIGPOLL] = { NSIGPOLL, SIL_POLL },
+ [SIGSYS] = { NSIGSYS, SIL_SYS },
+ };
+ if ((sig < ARRAY_SIZE(filter)) && (si_code <= filter[sig].limit)) {
+ layout = filter[sig].layout;
+ /* Handle the exceptions */
+ if ((sig == SIGBUS) &&
+ (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
+ layout = SIL_FAULT_MCEERR;
+ else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
+ layout = SIL_FAULT_BNDERR;
+#ifdef SEGV_PKUERR
+ else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
+ layout = SIL_FAULT_PKUERR;
+#endif
+ }
+ else if (si_code <= NSIGPOLL)
+ layout = SIL_POLL;
+ } else {
+ if (si_code == SI_TIMER)
+ layout = SIL_TIMER;
+ else if (si_code == SI_SIGIO)
+ layout = SIL_POLL;
+ else if (si_code < 0)
+ layout = SIL_RT;
+ }
+ return layout;
+}
+
+int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
+{
+ if (copy_to_user(to, from , sizeof(struct siginfo)))
+ return -EFAULT;
+ return 0;
+}
+
+#ifdef CONFIG_COMPAT
+int copy_siginfo_to_user32(struct compat_siginfo __user *to,
+ const struct siginfo *from)
+#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
+{
+ return __copy_siginfo_to_user32(to, from, in_x32_syscall());
+}
+int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
+ const struct siginfo *from, bool x32_ABI)
+#endif
+{
+ struct compat_siginfo new;
+ memset(&new, 0, sizeof(new));
+
+ new.si_signo = from->si_signo;
+ new.si_errno = from->si_errno;
+ new.si_code = from->si_code;
+ switch(siginfo_layout(from->si_signo, from->si_code)) {
+ case SIL_KILL:
+ new.si_pid = from->si_pid;
+ new.si_uid = from->si_uid;
+ break;
+ case SIL_TIMER:
+ new.si_tid = from->si_tid;
+ new.si_overrun = from->si_overrun;
+ new.si_int = from->si_int;
+ break;
+ case SIL_POLL:
+ new.si_band = from->si_band;
+ new.si_fd = from->si_fd;
+ break;
+ case SIL_FAULT:
+ new.si_addr = ptr_to_compat(from->si_addr);
+#ifdef __ARCH_SI_TRAPNO
+ new.si_trapno = from->si_trapno;
+#endif
+ break;
+ case SIL_FAULT_MCEERR:
+ new.si_addr = ptr_to_compat(from->si_addr);
+#ifdef __ARCH_SI_TRAPNO
+ new.si_trapno = from->si_trapno;
+#endif
+ new.si_addr_lsb = from->si_addr_lsb;
+ break;
+ case SIL_FAULT_BNDERR:
+ new.si_addr = ptr_to_compat(from->si_addr);
+#ifdef __ARCH_SI_TRAPNO
+ new.si_trapno = from->si_trapno;
+#endif
+ new.si_lower = ptr_to_compat(from->si_lower);
+ new.si_upper = ptr_to_compat(from->si_upper);
+ break;
+ case SIL_FAULT_PKUERR:
+ new.si_addr = ptr_to_compat(from->si_addr);
+#ifdef __ARCH_SI_TRAPNO
+ new.si_trapno = from->si_trapno;
+#endif
+ new.si_pkey = from->si_pkey;
+ break;
+ case SIL_CHLD:
+ new.si_pid = from->si_pid;
+ new.si_uid = from->si_uid;
+ new.si_status = from->si_status;
+#ifdef CONFIG_X86_X32_ABI
+ if (x32_ABI) {
+ new._sifields._sigchld_x32._utime = from->si_utime;
+ new._sifields._sigchld_x32._stime = from->si_stime;
+ } else
+#endif
+ {
+ new.si_utime = from->si_utime;
+ new.si_stime = from->si_stime;
+ }
+ break;
+ case SIL_RT:
+ new.si_pid = from->si_pid;
+ new.si_uid = from->si_uid;
+ new.si_int = from->si_int;
+ break;
+ case SIL_SYS:
+ new.si_call_addr = ptr_to_compat(from->si_call_addr);
+ new.si_syscall = from->si_syscall;
+ new.si_arch = from->si_arch;
+ break;
+ }
+
+ if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
+ return -EFAULT;
+
+ return 0;
+}
+
+int copy_siginfo_from_user32(struct siginfo *to,
+ const struct compat_siginfo __user *ufrom)
+{
+ struct compat_siginfo from;
+
+ if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
+ return -EFAULT;
+
+ clear_siginfo(to);
+ to->si_signo = from.si_signo;
+ to->si_errno = from.si_errno;
+ to->si_code = from.si_code;
+ switch(siginfo_layout(from.si_signo, from.si_code)) {
+ case SIL_KILL:
+ to->si_pid = from.si_pid;
+ to->si_uid = from.si_uid;
+ break;
+ case SIL_TIMER:
+ to->si_tid = from.si_tid;
+ to->si_overrun = from.si_overrun;
+ to->si_int = from.si_int;
+ break;
+ case SIL_POLL:
+ to->si_band = from.si_band;
+ to->si_fd = from.si_fd;
+ break;
+ case SIL_FAULT:
+ to->si_addr = compat_ptr(from.si_addr);
+#ifdef __ARCH_SI_TRAPNO
+ to->si_trapno = from.si_trapno;
+#endif
+ break;
+ case SIL_FAULT_MCEERR:
+ to->si_addr = compat_ptr(from.si_addr);
+#ifdef __ARCH_SI_TRAPNO
+ to->si_trapno = from.si_trapno;
+#endif
+ to->si_addr_lsb = from.si_addr_lsb;
+ break;
+ case SIL_FAULT_BNDERR:
+ to->si_addr = compat_ptr(from.si_addr);
+#ifdef __ARCH_SI_TRAPNO
+ to->si_trapno = from.si_trapno;
+#endif
+ to->si_lower = compat_ptr(from.si_lower);
+ to->si_upper = compat_ptr(from.si_upper);
+ break;
+ case SIL_FAULT_PKUERR:
+ to->si_addr = compat_ptr(from.si_addr);
+#ifdef __ARCH_SI_TRAPNO
+ to->si_trapno = from.si_trapno;
+#endif
+ to->si_pkey = from.si_pkey;
+ break;
+ case SIL_CHLD:
+ to->si_pid = from.si_pid;
+ to->si_uid = from.si_uid;
+ to->si_status = from.si_status;
+#ifdef CONFIG_X86_X32_ABI
+ if (in_x32_syscall()) {
+ to->si_utime = from._sifields._sigchld_x32._utime;
+ to->si_stime = from._sifields._sigchld_x32._stime;
+ } else
+#endif
+ {
+ to->si_utime = from.si_utime;
+ to->si_stime = from.si_stime;
+ }
+ break;
+ case SIL_RT:
+ to->si_pid = from.si_pid;
+ to->si_uid = from.si_uid;
+ to->si_int = from.si_int;
+ break;
+ case SIL_SYS:
+ to->si_call_addr = compat_ptr(from.si_call_addr);
+ to->si_syscall = from.si_syscall;
+ to->si_arch = from.si_arch;
+ break;
+ }
+ return 0;
+}
+#endif /* CONFIG_COMPAT */
+
+/**
+ * do_sigtimedwait - wait for queued signals specified in @which
+ * @which: queued signals to wait for
+ * @info: if non-null, the signal's siginfo is returned here
+ * @ts: upper bound on process time suspension
+ */
+static int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
+ const struct timespec *ts)
+{
+ ktime_t *to = NULL, timeout = KTIME_MAX;
+ struct task_struct *tsk = current;
+ sigset_t mask = *which;
+ int sig, ret = 0;
+
+ if (ts) {
+ if (!timespec_valid(ts))
+ return -EINVAL;
+ timeout = timespec_to_ktime(*ts);
+ to = &timeout;
+ }
+
+ /*
+ * Invert the set of allowed signals to get those we want to block.
+ */
+ sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
+ signotset(&mask);
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ sig = dequeue_signal(tsk, &mask, info);
+ if (!sig && timeout) {
+ /*
+ * None ready, temporarily unblock those we're interested
+ * while we are sleeping in so that we'll be awakened when
+ * they arrive. Unblocking is always fine, we can avoid
+ * set_current_blocked().
+ */
+ tsk->real_blocked = tsk->blocked;
+ sigandsets(&tsk->blocked, &tsk->blocked, &mask);
+ recalc_sigpending();
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ __set_current_state(TASK_INTERRUPTIBLE);
+ ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
+ HRTIMER_MODE_REL);
+ spin_lock_irq(&tsk->sighand->siglock);
+ __set_task_blocked(tsk, &tsk->real_blocked);
+ sigemptyset(&tsk->real_blocked);
+ sig = dequeue_signal(tsk, &mask, info);
+ }
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ if (sig)
+ return sig;
+ return ret ? -EINTR : -EAGAIN;
+}
+
+/**
+ * sys_rt_sigtimedwait - synchronously wait for queued signals specified
+ * in @uthese
+ * @uthese: queued signals to wait for
+ * @uinfo: if non-null, the signal's siginfo is returned here
+ * @uts: upper bound on process time suspension
+ * @sigsetsize: size of sigset_t type
+ */
+SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
+ siginfo_t __user *, uinfo, const struct timespec __user *, uts,
+ size_t, sigsetsize)
+{
+ sigset_t these;
+ struct timespec ts;
+ siginfo_t info;
+ int ret;
+
+ /* XXX: Don't preclude handling different sized sigset_t's. */
+ if (sigsetsize != sizeof(sigset_t))
+ return -EINVAL;
+
+ if (copy_from_user(&these, uthese, sizeof(these)))
+ return -EFAULT;
+
+ if (uts) {
+ if (copy_from_user(&ts, uts, sizeof(ts)))
+ return -EFAULT;
+ }
+
+ ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
+
+ if (ret > 0 && uinfo) {
+ if (copy_siginfo_to_user(uinfo, &info))
+ ret = -EFAULT;
+ }
+
+ return ret;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese,
+ struct compat_siginfo __user *, uinfo,
+ struct compat_timespec __user *, uts, compat_size_t, sigsetsize)
+{
+ sigset_t s;
+ struct timespec t;
+ siginfo_t info;
+ long ret;
+
+ if (sigsetsize != sizeof(sigset_t))
+ return -EINVAL;
+
+ if (get_compat_sigset(&s, uthese))
+ return -EFAULT;
+
+ if (uts) {
+ if (compat_get_timespec(&t, uts))
+ return -EFAULT;
+ }
+
+ ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
+
+ if (ret > 0 && uinfo) {
+ if (copy_siginfo_to_user32(uinfo, &info))
+ ret = -EFAULT;
+ }
+
+ return ret;
+}
+#endif
+
+/**
+ * sys_kill - send a signal to a process
+ * @pid: the PID of the process
+ * @sig: signal to be sent
+ */
+SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
+{
+ struct siginfo info;
+
+ clear_siginfo(&info);
+ info.si_signo = sig;
+ info.si_errno = 0;
+ info.si_code = SI_USER;
+ info.si_pid = task_tgid_vnr(current);
+ info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
+
+ return kill_something_info(sig, &info, pid);
+}
+
+static int
+do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
+{
+ struct task_struct *p;
+ int error = -ESRCH;
+
+ rcu_read_lock();
+ p = find_task_by_vpid(pid);
+ if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
+ error = check_kill_permission(sig, info, p);
+ /*
+ * The null signal is a permissions and process existence
+ * probe. No signal is actually delivered.
+ */
+ if (!error && sig) {
+ error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
+ /*
+ * If lock_task_sighand() failed we pretend the task
+ * dies after receiving the signal. The window is tiny,
+ * and the signal is private anyway.
+ */
+ if (unlikely(error == -ESRCH))
+ error = 0;
+ }
+ }
+ rcu_read_unlock();
+
+ return error;
+}
+
+static int do_tkill(pid_t tgid, pid_t pid, int sig)
+{
+ struct siginfo info;
+
+ clear_siginfo(&info);
+ info.si_signo = sig;
+ info.si_errno = 0;
+ info.si_code = SI_TKILL;
+ info.si_pid = task_tgid_vnr(current);
+ info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
+
+ return do_send_specific(tgid, pid, sig, &info);
+}
+
+/**
+ * sys_tgkill - send signal to one specific thread
+ * @tgid: the thread group ID of the thread
+ * @pid: the PID of the thread
+ * @sig: signal to be sent
+ *
+ * This syscall also checks the @tgid and returns -ESRCH even if the PID
+ * exists but it's not belonging to the target process anymore. This
+ * method solves the problem of threads exiting and PIDs getting reused.
+ */
+SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
+{
+ /* This is only valid for single tasks */
+ if (pid <= 0 || tgid <= 0)
+ return -EINVAL;
+
+ return do_tkill(tgid, pid, sig);
+}
+
+/**
+ * sys_tkill - send signal to one specific task
+ * @pid: the PID of the task
+ * @sig: signal to be sent
+ *
+ * Send a signal to only one task, even if it's a CLONE_THREAD task.
+ */
+SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
+{
+ /* This is only valid for single tasks */
+ if (pid <= 0)
+ return -EINVAL;
+
+ return do_tkill(0, pid, sig);
+}
+
+static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
+{
+ /* Not even root can pretend to send signals from the kernel.
+ * Nor can they impersonate a kill()/tgkill(), which adds source info.
+ */
+ if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
+ (task_pid_vnr(current) != pid))
+ return -EPERM;
+
+ info->si_signo = sig;
+
+ /* POSIX.1b doesn't mention process groups. */
+ return kill_proc_info(sig, info, pid);
+}
+
+/**
+ * sys_rt_sigqueueinfo - send signal information to a signal
+ * @pid: the PID of the thread
+ * @sig: signal to be sent
+ * @uinfo: signal info to be sent
+ */
+SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
+ siginfo_t __user *, uinfo)
+{
+ siginfo_t info;
+ if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
+ return -EFAULT;
+ return do_rt_sigqueueinfo(pid, sig, &info);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
+ compat_pid_t, pid,
+ int, sig,
+ struct compat_siginfo __user *, uinfo)
+{
+ siginfo_t info;
+ int ret = copy_siginfo_from_user32(&info, uinfo);
+ if (unlikely(ret))
+ return ret;
+ return do_rt_sigqueueinfo(pid, sig, &info);
+}
+#endif
+
+static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
+{
+ /* This is only valid for single tasks */
+ if (pid <= 0 || tgid <= 0)
+ return -EINVAL;
+
+ /* Not even root can pretend to send signals from the kernel.
+ * Nor can they impersonate a kill()/tgkill(), which adds source info.
+ */
+ if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
+ (task_pid_vnr(current) != pid))
+ return -EPERM;
+
+ info->si_signo = sig;
+
+ return do_send_specific(tgid, pid, sig, info);
+}
+
+SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
+ siginfo_t __user *, uinfo)
+{
+ siginfo_t info;
+
+ if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
+ return -EFAULT;
+
+ return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
+ compat_pid_t, tgid,
+ compat_pid_t, pid,
+ int, sig,
+ struct compat_siginfo __user *, uinfo)
+{
+ siginfo_t info;
+
+ if (copy_siginfo_from_user32(&info, uinfo))
+ return -EFAULT;
+ return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
+}
+#endif
+
+/*
+ * For kthreads only, must not be used if cloned with CLONE_SIGHAND
+ */
+void kernel_sigaction(int sig, __sighandler_t action)
+{
+ spin_lock_irq(¤t->sighand->siglock);
+ current->sighand->action[sig - 1].sa.sa_handler = action;
+ if (action == SIG_IGN) {
+ sigset_t mask;
+
+ sigemptyset(&mask);
+ sigaddset(&mask, sig);
+
+ flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
+ flush_sigqueue_mask(&mask, ¤t->pending);
+ recalc_sigpending();
+ }
+ spin_unlock_irq(¤t->sighand->siglock);
+}
+EXPORT_SYMBOL(kernel_sigaction);
+
+void __weak sigaction_compat_abi(struct k_sigaction *act,
+ struct k_sigaction *oact)
+{
+}
+
+int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
+{
+ struct task_struct *p = current, *t;
+ struct k_sigaction *k;
+ sigset_t mask;
+
+ if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
+ return -EINVAL;
+
+ k = &p->sighand->action[sig-1];
+
+ spin_lock_irq(&p->sighand->siglock);
+ if (oact)
+ *oact = *k;
+
+ sigaction_compat_abi(act, oact);
+
+ if (act) {
+ sigdelsetmask(&act->sa.sa_mask,
+ sigmask(SIGKILL) | sigmask(SIGSTOP));
+ *k = *act;
+ /*
+ * POSIX 3.3.1.3:
+ * "Setting a signal action to SIG_IGN for a signal that is
+ * pending shall cause the pending signal to be discarded,
+ * whether or not it is blocked."
+ *
+ * "Setting a signal action to SIG_DFL for a signal that is
+ * pending and whose default action is to ignore the signal
+ * (for example, SIGCHLD), shall cause the pending signal to
+ * be discarded, whether or not it is blocked"
+ */
+ if (sig_handler_ignored(sig_handler(p, sig), sig)) {
+ sigemptyset(&mask);
+ sigaddset(&mask, sig);
+ flush_sigqueue_mask(&mask, &p->signal->shared_pending);
+ for_each_thread(p, t)
+ flush_sigqueue_mask(&mask, &t->pending);
+ }
+ }
+
+ spin_unlock_irq(&p->sighand->siglock);
+ return 0;
+}
+
+static int
+do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
+ size_t min_ss_size)
+{
+ struct task_struct *t = current;
+
+ if (oss) {
+ memset(oss, 0, sizeof(stack_t));
+ oss->ss_sp = (void __user *) t->sas_ss_sp;
+ oss->ss_size = t->sas_ss_size;
+ oss->ss_flags = sas_ss_flags(sp) |
+ (current->sas_ss_flags & SS_FLAG_BITS);
+ }
+
+ if (ss) {
+ void __user *ss_sp = ss->ss_sp;
+ size_t ss_size = ss->ss_size;
+ unsigned ss_flags = ss->ss_flags;
+ int ss_mode;
+
+ if (unlikely(on_sig_stack(sp)))
+ return -EPERM;
+
+ ss_mode = ss_flags & ~SS_FLAG_BITS;
+ if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
+ ss_mode != 0))
+ return -EINVAL;
+
+ if (ss_mode == SS_DISABLE) {
+ ss_size = 0;
+ ss_sp = NULL;
+ } else {
+ if (unlikely(ss_size < min_ss_size))
+ return -ENOMEM;
+ }
+
+ t->sas_ss_sp = (unsigned long) ss_sp;
+ t->sas_ss_size = ss_size;
+ t->sas_ss_flags = ss_flags;
+ }
+ return 0;
+}
+
+SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
+{
+ stack_t new, old;
+ int err;
+ if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
+ return -EFAULT;
+ err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
+ current_user_stack_pointer(),
+ MINSIGSTKSZ);
+ if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
+ err = -EFAULT;
+ return err;
+}
+
+int restore_altstack(const stack_t __user *uss)
+{
+ stack_t new;
+ if (copy_from_user(&new, uss, sizeof(stack_t)))
+ return -EFAULT;
+ (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
+ MINSIGSTKSZ);
+ /* squash all but EFAULT for now */
+ return 0;
+}
+
+int __save_altstack(stack_t __user *uss, unsigned long sp)
+{
+ struct task_struct *t = current;
+ int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
+ __put_user(t->sas_ss_flags, &uss->ss_flags) |
+ __put_user(t->sas_ss_size, &uss->ss_size);
+ if (err)
+ return err;
+ if (t->sas_ss_flags & SS_AUTODISARM)
+ sas_ss_reset(t);
+ return 0;
+}
+
+#ifdef CONFIG_COMPAT
+static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
+ compat_stack_t __user *uoss_ptr)
+{
+ stack_t uss, uoss;
+ int ret;
+
+ if (uss_ptr) {
+ compat_stack_t uss32;
+ if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
+ return -EFAULT;
+ uss.ss_sp = compat_ptr(uss32.ss_sp);
+ uss.ss_flags = uss32.ss_flags;
+ uss.ss_size = uss32.ss_size;
+ }
+ ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
+ compat_user_stack_pointer(),
+ COMPAT_MINSIGSTKSZ);
+ if (ret >= 0 && uoss_ptr) {
+ compat_stack_t old;
+ memset(&old, 0, sizeof(old));
+ old.ss_sp = ptr_to_compat(uoss.ss_sp);
+ old.ss_flags = uoss.ss_flags;
+ old.ss_size = uoss.ss_size;
+ if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
+ ret = -EFAULT;
+ }
+ return ret;
+}
+
+COMPAT_SYSCALL_DEFINE2(sigaltstack,
+ const compat_stack_t __user *, uss_ptr,
+ compat_stack_t __user *, uoss_ptr)
+{
+ return do_compat_sigaltstack(uss_ptr, uoss_ptr);
+}
+
+int compat_restore_altstack(const compat_stack_t __user *uss)
+{
+ int err = do_compat_sigaltstack(uss, NULL);
+ /* squash all but -EFAULT for now */
+ return err == -EFAULT ? err : 0;
+}
+
+int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
+{
+ int err;
+ struct task_struct *t = current;
+ err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
+ &uss->ss_sp) |
+ __put_user(t->sas_ss_flags, &uss->ss_flags) |
+ __put_user(t->sas_ss_size, &uss->ss_size);
+ if (err)
+ return err;
+ if (t->sas_ss_flags & SS_AUTODISARM)
+ sas_ss_reset(t);
+ return 0;
+}
+#endif
+
+#ifdef __ARCH_WANT_SYS_SIGPENDING
+
+/**
+ * sys_sigpending - examine pending signals
+ * @uset: where mask of pending signal is returned
+ */
+SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
+{
+ sigset_t set;
+
+ if (sizeof(old_sigset_t) > sizeof(*uset))
+ return -EINVAL;
+
+ do_sigpending(&set);
+
+ if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
+ return -EFAULT;
+
+ return 0;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
+{
+ sigset_t set;
+
+ do_sigpending(&set);
+
+ return put_user(set.sig[0], set32);
+}
+#endif
+
+#endif
+
+#ifdef __ARCH_WANT_SYS_SIGPROCMASK
+/**
+ * sys_sigprocmask - examine and change blocked signals
+ * @how: whether to add, remove, or set signals
+ * @nset: signals to add or remove (if non-null)
+ * @oset: previous value of signal mask if non-null
+ *
+ * Some platforms have their own version with special arguments;
+ * others support only sys_rt_sigprocmask.
+ */
+
+SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
+ old_sigset_t __user *, oset)
+{
+ old_sigset_t old_set, new_set;
+ sigset_t new_blocked;
+
+ old_set = current->blocked.sig[0];
+
+ if (nset) {
+ if (copy_from_user(&new_set, nset, sizeof(*nset)))
+ return -EFAULT;
+
+ new_blocked = current->blocked;
+
+ switch (how) {
+ case SIG_BLOCK:
+ sigaddsetmask(&new_blocked, new_set);
+ break;
+ case SIG_UNBLOCK:
+ sigdelsetmask(&new_blocked, new_set);
+ break;
+ case SIG_SETMASK:
+ new_blocked.sig[0] = new_set;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ set_current_blocked(&new_blocked);
+ }
+
+ if (oset) {
+ if (copy_to_user(oset, &old_set, sizeof(*oset)))
+ return -EFAULT;
+ }
+
+ return 0;
+}
+#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
+
+#ifndef CONFIG_ODD_RT_SIGACTION
+/**
+ * sys_rt_sigaction - alter an action taken by a process
+ * @sig: signal to be sent
+ * @act: new sigaction
+ * @oact: used to save the previous sigaction
+ * @sigsetsize: size of sigset_t type
+ */
+SYSCALL_DEFINE4(rt_sigaction, int, sig,
+ const struct sigaction __user *, act,
+ struct sigaction __user *, oact,
+ size_t, sigsetsize)
+{
+ struct k_sigaction new_sa, old_sa;
+ int ret;
+
+ /* XXX: Don't preclude handling different sized sigset_t's. */
+ if (sigsetsize != sizeof(sigset_t))
+ return -EINVAL;
+
+ if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
+ return -EFAULT;
+
+ ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
+ if (ret)
+ return ret;
+
+ if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
+ return -EFAULT;
+
+ return 0;
+}
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
+ const struct compat_sigaction __user *, act,
+ struct compat_sigaction __user *, oact,
+ compat_size_t, sigsetsize)
+{
+ struct k_sigaction new_ka, old_ka;
+#ifdef __ARCH_HAS_SA_RESTORER
+ compat_uptr_t restorer;
+#endif
+ int ret;
+
+ /* XXX: Don't preclude handling different sized sigset_t's. */
+ if (sigsetsize != sizeof(compat_sigset_t))
+ return -EINVAL;
+
+ if (act) {
+ compat_uptr_t handler;
+ ret = get_user(handler, &act->sa_handler);
+ new_ka.sa.sa_handler = compat_ptr(handler);
+#ifdef __ARCH_HAS_SA_RESTORER
+ ret |= get_user(restorer, &act->sa_restorer);
+ new_ka.sa.sa_restorer = compat_ptr(restorer);
+#endif
+ ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
+ ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
+ if (ret)
+ return -EFAULT;
+ }
+
+ ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+ if (!ret && oact) {
+ ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
+ &oact->sa_handler);
+ ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
+ sizeof(oact->sa_mask));
+ ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
+#ifdef __ARCH_HAS_SA_RESTORER
+ ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
+ &oact->sa_restorer);
+#endif
+ }
+ return ret;
+}
+#endif
+#endif /* !CONFIG_ODD_RT_SIGACTION */
+
+#ifdef CONFIG_OLD_SIGACTION
+SYSCALL_DEFINE3(sigaction, int, sig,
+ const struct old_sigaction __user *, act,
+ struct old_sigaction __user *, oact)
+{
+ struct k_sigaction new_ka, old_ka;
+ int ret;
+
+ if (act) {
+ old_sigset_t mask;
+ if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
+ __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
+ __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
+ __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
+ __get_user(mask, &act->sa_mask))
+ return -EFAULT;
+#ifdef __ARCH_HAS_KA_RESTORER
+ new_ka.ka_restorer = NULL;
+#endif
+ siginitset(&new_ka.sa.sa_mask, mask);
+ }
+
+ ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+
+ if (!ret && oact) {
+ if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
+ __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
+ __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
+ __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
+ __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
+ return -EFAULT;
+ }
+
+ return ret;
+}
+#endif
+#ifdef CONFIG_COMPAT_OLD_SIGACTION
+COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
+ const struct compat_old_sigaction __user *, act,
+ struct compat_old_sigaction __user *, oact)
+{
+ struct k_sigaction new_ka, old_ka;
+ int ret;
+ compat_old_sigset_t mask;
+ compat_uptr_t handler, restorer;
+
+ if (act) {
+ if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
+ __get_user(handler, &act->sa_handler) ||
+ __get_user(restorer, &act->sa_restorer) ||
+ __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
+ __get_user(mask, &act->sa_mask))
+ return -EFAULT;
+
+#ifdef __ARCH_HAS_KA_RESTORER
+ new_ka.ka_restorer = NULL;
+#endif
+ new_ka.sa.sa_handler = compat_ptr(handler);
+ new_ka.sa.sa_restorer = compat_ptr(restorer);
+ siginitset(&new_ka.sa.sa_mask, mask);
+ }
+
+ ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+
+ if (!ret && oact) {
+ if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
+ __put_user(ptr_to_compat(old_ka.sa.sa_handler),
+ &oact->sa_handler) ||
+ __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
+ &oact->sa_restorer) ||
+ __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
+ __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
+ return -EFAULT;
+ }
+ return ret;
+}
+#endif
+
+#ifdef CONFIG_SGETMASK_SYSCALL
+
+/*
+ * For backwards compatibility. Functionality superseded by sigprocmask.
+ */
+SYSCALL_DEFINE0(sgetmask)
+{
+ /* SMP safe */
+ return current->blocked.sig[0];
+}
+
+SYSCALL_DEFINE1(ssetmask, int, newmask)
+{
+ int old = current->blocked.sig[0];
+ sigset_t newset;
+
+ siginitset(&newset, newmask);
+ set_current_blocked(&newset);
+
+ return old;
+}
+#endif /* CONFIG_SGETMASK_SYSCALL */
+
+#ifdef __ARCH_WANT_SYS_SIGNAL
+/*
+ * For backwards compatibility. Functionality superseded by sigaction.
+ */
+SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
+{
+ struct k_sigaction new_sa, old_sa;
+ int ret;
+
+ new_sa.sa.sa_handler = handler;
+ new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
+ sigemptyset(&new_sa.sa.sa_mask);
+
+ ret = do_sigaction(sig, &new_sa, &old_sa);
+
+ return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
+}
+#endif /* __ARCH_WANT_SYS_SIGNAL */
+
+#ifdef __ARCH_WANT_SYS_PAUSE
+
+SYSCALL_DEFINE0(pause)
+{
+ while (!signal_pending(current)) {
+ __set_current_state(TASK_INTERRUPTIBLE);
+ schedule();
+ }
+ return -ERESTARTNOHAND;
+}
+
+#endif
+
+static int sigsuspend(sigset_t *set)
+{
+ current->saved_sigmask = current->blocked;
+ set_current_blocked(set);
+
+ while (!signal_pending(current)) {
+ __set_current_state(TASK_INTERRUPTIBLE);
+ schedule();
+ }
+ set_restore_sigmask();
+ return -ERESTARTNOHAND;
+}
+
+/**
+ * sys_rt_sigsuspend - replace the signal mask for a value with the
+ * @unewset value until a signal is received
+ * @unewset: new signal mask value
+ * @sigsetsize: size of sigset_t type
+ */
+SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
+{
+ sigset_t newset;
+
+ /* XXX: Don't preclude handling different sized sigset_t's. */
+ if (sigsetsize != sizeof(sigset_t))
+ return -EINVAL;
+
+ if (copy_from_user(&newset, unewset, sizeof(newset)))
+ return -EFAULT;
+ return sigsuspend(&newset);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
+{
+ sigset_t newset;
+
+ /* XXX: Don't preclude handling different sized sigset_t's. */
+ if (sigsetsize != sizeof(sigset_t))
+ return -EINVAL;
+
+ if (get_compat_sigset(&newset, unewset))
+ return -EFAULT;
+ return sigsuspend(&newset);
+}
+#endif
+
+#ifdef CONFIG_OLD_SIGSUSPEND
+SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
+{
+ sigset_t blocked;
+ siginitset(&blocked, mask);
+ return sigsuspend(&blocked);
+}
+#endif
+#ifdef CONFIG_OLD_SIGSUSPEND3
+SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
+{
+ sigset_t blocked;
+ siginitset(&blocked, mask);
+ return sigsuspend(&blocked);
+}
+#endif
+
+__weak const char *arch_vma_name(struct vm_area_struct *vma)
+{
+ return NULL;
+}
+
+void __init signals_init(void)
+{
+ /* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */
+ BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE
+ != offsetof(struct siginfo, _sifields._pad));
+ BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
+
+ sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
+}
+
+#ifdef CONFIG_KGDB_KDB
+#include <linux/kdb.h>
+/*
+ * kdb_send_sig - Allows kdb to send signals without exposing
+ * signal internals. This function checks if the required locks are
+ * available before calling the main signal code, to avoid kdb
+ * deadlocks.
+ */
+void kdb_send_sig(struct task_struct *t, int sig)
+{
+ static struct task_struct *kdb_prev_t;
+ int new_t, ret;
+ if (!spin_trylock(&t->sighand->siglock)) {
+ kdb_printf("Can't do kill command now.\n"
+ "The sigmask lock is held somewhere else in "
+ "kernel, try again later\n");
+ return;
+ }
+ new_t = kdb_prev_t != t;
+ kdb_prev_t = t;
+ if (t->state != TASK_RUNNING && new_t) {
+ spin_unlock(&t->sighand->siglock);
+ kdb_printf("Process is not RUNNING, sending a signal from "
+ "kdb risks deadlock\n"
+ "on the run queue locks. "
+ "The signal has _not_ been sent.\n"
+ "Reissue the kill command if you want to risk "
+ "the deadlock.\n");
+ return;
+ }
+ ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
+ spin_unlock(&t->sighand->siglock);
+ if (ret)
+ kdb_printf("Fail to deliver Signal %d to process %d.\n",
+ sig, t->pid);
+ else
+ kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
+}
+#endif /* CONFIG_KGDB_KDB */