#include <linux/slab.h>
#include <linux/module.h>
-#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/fs.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>
+#define CREATE_TRACE_POINTS
+#include <trace/events/signal.h>
#include <asm/param.h>
#include <asm/uaccess.h>
static struct kmem_cache *sigqueue_cachep;
-/*
- * In POSIX a signal is sent either to a specific thread (Linux task)
- * or to the process as a whole (Linux thread group). How the signal
- * is sent determines whether it's to one thread or the whole group,
- * which determines which signal mask(s) are involved in blocking it
- * from being delivered until later. When the signal is delivered,
- * either it's caught or ignored by a user handler or it has a default
- * effect that applies to the whole thread group (POSIX process).
- *
- * The possible effects an unblocked signal set to SIG_DFL can have are:
- * ignore - Nothing Happens
- * terminate - kill the process, i.e. all threads in the group,
- * similar to exit_group. The group leader (only) reports
- * WIFSIGNALED status to its parent.
- * coredump - write a core dump file describing all threads using
- * the same mm and then kill all those threads
- * stop - stop all the threads in the group, i.e. TASK_STOPPED state
- *
- * SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.
- * Other signals when not blocked and set to SIG_DFL behaves as follows.
- * The job control signals also have other special effects.
- *
- * +--------------------+------------------+
- * | POSIX signal | default action |
- * +--------------------+------------------+
- * | SIGHUP | terminate |
- * | SIGINT | terminate |
- * | SIGQUIT | coredump |
- * | SIGILL | coredump |
- * | SIGTRAP | coredump |
- * | SIGABRT/SIGIOT | coredump |
- * | SIGBUS | coredump |
- * | SIGFPE | coredump |
- * | SIGKILL | terminate(+) |
- * | SIGUSR1 | terminate |
- * | SIGSEGV | coredump |
- * | SIGUSR2 | terminate |
- * | SIGPIPE | terminate |
- * | SIGALRM | terminate |
- * | SIGTERM | terminate |
- * | SIGCHLD | ignore |
- * | SIGCONT | ignore(*) |
- * | SIGSTOP | stop(*)(+) |
- * | SIGTSTP | stop(*) |
- * | SIGTTIN | stop(*) |
- * | SIGTTOU | stop(*) |
- * | SIGURG | ignore |
- * | SIGXCPU | coredump |
- * | SIGXFSZ | coredump |
- * | SIGVTALRM | terminate |
- * | SIGPROF | terminate |
- * | SIGPOLL/SIGIO | terminate |
- * | SIGSYS/SIGUNUSED | coredump |
- * | SIGSTKFLT | terminate |
- * | SIGWINCH | ignore |
- * | SIGPWR | terminate |
- * | SIGRTMIN-SIGRTMAX | terminate |
- * +--------------------+------------------+
- * | non-POSIX signal | default action |
- * +--------------------+------------------+
- * | SIGEMT | coredump |
- * +--------------------+------------------+
- *
- * (+) For SIGKILL and SIGSTOP the action is "always", not just "default".
- * (*) Special job control effects:
- * When SIGCONT is sent, it resumes the process (all threads in the group)
- * from TASK_STOPPED state and also clears any pending/queued stop signals
- * (any of those marked with "stop(*)"). This happens regardless of blocking,
- * catching, or ignoring SIGCONT. When any stop signal is sent, it clears
- * any pending/queued SIGCONT signals; this happens regardless of blocking,
- * catching, or ignored the stop signal, though (except for SIGSTOP) the
- * default action of stopping the process may happen later or never.
- */
-
-#ifdef SIGEMT
-#define M_SIGEMT M(SIGEMT)
-#else
-#define M_SIGEMT 0
-#endif
+int print_fatal_signals __read_mostly;
-#if SIGRTMIN > BITS_PER_LONG
-#define M(sig) (1ULL << ((sig)-1))
-#else
-#define M(sig) (1UL << ((sig)-1))
-#endif
-#define T(sig, mask) (M(sig) & (mask))
-
-#define SIG_KERNEL_ONLY_MASK (\
- M(SIGKILL) | M(SIGSTOP) )
-
-#define SIG_KERNEL_STOP_MASK (\
- M(SIGSTOP) | M(SIGTSTP) | M(SIGTTIN) | M(SIGTTOU) )
-
-#define SIG_KERNEL_COREDUMP_MASK (\
- M(SIGQUIT) | M(SIGILL) | M(SIGTRAP) | M(SIGABRT) | \
- M(SIGFPE) | M(SIGSEGV) | M(SIGBUS) | M(SIGSYS) | \
- M(SIGXCPU) | M(SIGXFSZ) | M_SIGEMT )
+static void __user *sig_handler(struct task_struct *t, int sig)
+{
+ return t->sighand->action[sig - 1].sa.sa_handler;
+}
-#define SIG_KERNEL_IGNORE_MASK (\
- M(SIGCONT) | M(SIGCHLD) | M(SIGWINCH) | M(SIGURG) )
+static int 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));
+}
-#define sig_kernel_only(sig) \
- (((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_ONLY_MASK))
-#define sig_kernel_coredump(sig) \
- (((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_COREDUMP_MASK))
-#define sig_kernel_ignore(sig) \
- (((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_IGNORE_MASK))
-#define sig_kernel_stop(sig) \
- (((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_STOP_MASK))
+static int sig_task_ignored(struct task_struct *t, int sig,
+ int from_ancestor_ns)
+{
+ void __user *handler;
-#define sig_needs_tasklist(sig) ((sig) == SIGCONT)
+ handler = sig_handler(t, sig);
-#define sig_user_defined(t, signr) \
- (((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) && \
- ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN))
+ if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
+ handler == SIG_DFL && !from_ancestor_ns)
+ return 1;
-#define sig_fatal(t, signr) \
- (!T(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
- (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
+ return sig_handler_ignored(handler, sig);
+}
-static int sig_ignored(struct task_struct *t, int sig)
+static int sig_ignored(struct task_struct *t, int sig, int from_ancestor_ns)
{
- void __user * handler;
-
- /*
- * Tracers always want to know about signals..
- */
- if (t->ptrace & PT_PTRACED)
- return 0;
-
/*
* Blocked signals are never ignored, since the
* signal handler may change by the time it is
* unblocked.
*/
- if (sigismember(&t->blocked, sig))
+ if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
return 0;
- /* Is it explicitly or implicitly ignored? */
- handler = t->sighand->action[sig-1].sa.sa_handler;
- return handler == SIG_IGN ||
- (handler == SIG_DFL && sig_kernel_ignore(sig));
+ if (!sig_task_ignored(t, sig, from_ancestor_ns))
+ return 0;
+
+ /*
+ * Tracers may want to know about even ignored signals.
+ */
+ return !tracehook_consider_ignored_signal(t, sig);
}
/*
#define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
-fastcall void recalc_sigpending_tsk(struct task_struct *t)
+static int recalc_sigpending_tsk(struct task_struct *t)
{
if (t->signal->group_stop_count > 0 ||
- (freezing(t)) ||
PENDING(&t->pending, &t->blocked) ||
- PENDING(&t->signal->shared_pending, &t->blocked))
+ PENDING(&t->signal->shared_pending, &t->blocked)) {
set_tsk_thread_flag(t, TIF_SIGPENDING);
- else
- clear_tsk_thread_flag(t, TIF_SIGPENDING);
+ return 1;
+ }
+ /*
+ * 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 0;
+}
+
+/*
+ * 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)
{
- recalc_sigpending_tsk(current);
+ if (unlikely(tracehook_force_sigpending()))
+ set_thread_flag(TIF_SIGPENDING);
+ else if (!recalc_sigpending_tsk(current) && !freezing(current))
+ clear_thread_flag(TIF_SIGPENDING);
+
}
/* Given the mask, find the first available signal that should be serviced. */
-static int
-next_signal(struct sigpending *pending, sigset_t *mask)
+#define SYNCHRONOUS_MASK \
+ (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
+ sigmask(SIGTRAP) | sigmask(SIGFPE))
+
+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 = 0; i < _NSIG_WORDS; ++i, ++s, ++m)
- if ((x = *s &~ *m) != 0) {
- sig = ffz(~x) + i*_NSIG_BPW + 1;
- break;
- }
+ for (i = 1; i < _NSIG_WORDS; ++i) {
+ x = *++s &~ *++m;
+ if (!x)
+ continue;
+ sig = ffz(~x) + i*_NSIG_BPW + 1;
+ break;
+ }
break;
- case 2: if ((x = s[0] &~ m[0]) != 0)
- sig = 1;
- else if ((x = s[1] &~ m[1]) != 0)
- sig = _NSIG_BPW + 1;
- else
+ case 2:
+ x = s[1] &~ m[1];
+ if (!x)
break;
- sig += ffz(~x);
+ sig = ffz(~x) + _NSIG_BPW + 1;
break;
- case 1: if ((x = *s &~ *m) != 0)
- sig = ffz(~x) + 1;
+ case 1:
+ /* Nothing to do */
break;
}
-
+
return sig;
}
-static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
- int override_rlimit)
+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;
+
+ printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
+ current->comm, current->pid, sig);
+}
+
+/*
+ * allocate a new signal queue record
+ * - this may be called without locks if and only if t == current, otherwise an
+ * appopriate 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;
/*
- * In order to avoid problems with "switch_user()", we want to make
- * sure that the compiler doesn't re-load "t->user"
+ * Protect access to @t credentials. This can go away when all
+ * callers hold rcu read lock.
*/
- user = t->user;
- barrier();
+ rcu_read_lock();
+ user = get_uid(__task_cred(t)->user);
atomic_inc(&user->sigpending);
+ rcu_read_unlock();
+
if (override_rlimit ||
atomic_read(&user->sigpending) <=
- t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
+ 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 = get_uid(user);
+ q->user = user;
}
- return(q);
+
+ return q;
}
static void __sigqueue_free(struct sigqueue *q)
/*
* Flush all pending signals for a task.
*/
+void __flush_signals(struct task_struct *t)
+{
+ clear_tsk_thread_flag(t, TIF_SIGPENDING);
+ flush_sigqueue(&t->pending);
+ flush_sigqueue(&t->signal->shared_pending);
+}
+
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);
+ __flush_signals(t);
spin_unlock_irqrestore(&t->sighand->siglock, flags);
}
+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);
+}
+
+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.
*/
}
}
+int 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 1;
+ if (handler != SIG_IGN && handler != SIG_DFL)
+ return 0;
+ return !tracehook_consider_fatal_signal(tsk, sig);
+}
+
/* Notify the system that a driver wants to block all signals for this
* process, and wants to be notified if any signals at all were to be
spin_unlock_irqrestore(¤t->sighand->siglock, flags);
}
-static int collect_signal(int sig, struct sigpending *list, siginfo_t *info)
+static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
{
struct sigqueue *q, *first = NULL;
- int still_pending = 0;
-
- if (unlikely(!sigismember(&list->signal, sig)))
- return 0;
/*
* Collect the siginfo appropriate to this signal. Check if
*/
list_for_each_entry(q, &list->list, list) {
if (q->info.si_signo == sig) {
- if (first) {
- still_pending = 1;
- break;
- }
+ 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);
__sigqueue_free(first);
- if (!still_pending)
- sigdelset(&list->signal, sig);
} 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.
*/
- sigdelset(&list->signal, sig);
info->si_signo = sig;
info->si_errno = 0;
- info->si_code = 0;
+ info->si_code = SI_USER;
info->si_pid = 0;
info->si_uid = 0;
}
- return 1;
}
static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
}
}
- if (!collect_signal(sig, pending, info))
- sig = 0;
+ collect_signal(sig, pending, info);
}
return sig;
*/
int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
{
- int signr = __dequeue_signal(&tsk->pending, mask, info);
- if (!signr)
+ int signr;
+
+ /* We only dequeue private signals from ourselves, we don't let
+ * signalfd steal them
+ */
+ signr = __dequeue_signal(&tsk->pending, mask, info);
+ if (!signr) {
signr = __dequeue_signal(&tsk->signal->shared_pending,
mask, info);
- recalc_sigpending_tsk(tsk);
- if (signr && 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.
- */
- if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT))
- tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
- }
- if ( signr &&
- ((info->si_code & __SI_MASK) == __SI_TIMER) &&
- info->si_sys_private){
+ /*
+ * 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.tv64 != 0) {
+ hrtimer_forward(tmr, tmr->base->get_time(),
+ tsk->signal->it_real_incr);
+ hrtimer_restart(tmr);
+ }
+ }
+ }
+
+ 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.
+ */
+ tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
+ }
+ if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
/*
* Release the siglock to ensure proper locking order
* of timer locks outside of siglocks. Note, we leave
set_tsk_thread_flag(t, TIF_SIGPENDING);
/*
- * For SIGKILL, we want to wake it up in the stopped/traced case.
- * We don't check t->state here because there is a race with it
+ * For SIGKILL, we want to 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.
*/
mask = TASK_INTERRUPTIBLE;
if (resume)
- mask |= TASK_STOPPED | TASK_TRACED;
+ mask |= TASK_WAKEKILL;
if (!wake_up_state(t, mask))
kick_process(t);
}
return 1;
}
+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));
+}
+
/*
* Bad permissions for sending the signal
+ * - the caller must hold at least the RCU read lock
*/
static int check_kill_permission(int sig, struct siginfo *info,
struct task_struct *t)
{
- int error = -EINVAL;
+ const struct cred *cred = current_cred(), *tcred;
+ struct pid *sid;
+ int error;
+
if (!valid_signal(sig))
- return error;
- error = -EPERM;
- if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
- && ((sig != SIGCONT) ||
- (process_session(current) != process_session(t)))
- && (current->euid ^ t->suid) && (current->euid ^ t->uid)
- && (current->uid ^ t->suid) && (current->uid ^ t->uid)
- && !capable(CAP_KILL))
+ return -EINVAL;
+
+ if (!si_fromuser(info))
+ return 0;
+
+ error = audit_signal_info(sig, t); /* Let audit system see the signal */
+ if (error)
return error;
- error = security_task_kill(t, info, sig, 0);
- if (!error)
- audit_signal_info(sig, t); /* Let audit system see the signal */
- return error;
-}
+ tcred = __task_cred(t);
+ if ((cred->euid ^ tcred->suid) &&
+ (cred->euid ^ tcred->uid) &&
+ (cred->uid ^ tcred->suid) &&
+ (cred->uid ^ tcred->uid) &&
+ !capable(CAP_KILL)) {
+ 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;
+ }
+ }
-/* forward decl */
-static void do_notify_parent_cldstop(struct task_struct *tsk, int why);
+ return security_task_kill(t, info, sig, 0);
+}
/*
- * Handle magic process-wide effects of stop/continue signals.
- * Unlike the signal actions, these happen immediately at signal-generation
+ * 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.
+ * 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 void handle_stop_signal(int sig, struct task_struct *p)
+static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns)
{
+ struct signal_struct *signal = p->signal;
struct task_struct *t;
- if (p->signal->flags & SIGNAL_GROUP_EXIT)
+ if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) {
/*
- * The process is in the middle of dying already.
+ * The process is in the middle of dying, nothing to do.
*/
- return;
-
- if (sig_kernel_stop(sig)) {
+ } else if (sig_kernel_stop(sig)) {
/*
* This is a stop signal. Remove SIGCONT from all queues.
*/
- rm_from_queue(sigmask(SIGCONT), &p->signal->shared_pending);
+ rm_from_queue(sigmask(SIGCONT), &signal->shared_pending);
t = p;
do {
rm_from_queue(sigmask(SIGCONT), &t->pending);
- t = next_thread(t);
- } while (t != p);
+ } while_each_thread(p, t);
} else if (sig == SIGCONT) {
+ unsigned int why;
/*
* Remove all stop signals from all queues,
* and wake all threads.
*/
- if (unlikely(p->signal->group_stop_count > 0)) {
- /*
- * There was a group stop in progress. We'll
- * pretend it finished before we got here. We are
- * obliged to report it to the parent: if the
- * SIGSTOP happened "after" this SIGCONT, then it
- * would have cleared this pending SIGCONT. If it
- * happened "before" this SIGCONT, then the parent
- * got the SIGCHLD about the stop finishing before
- * the continue happened. We do the notification
- * now, and it's as if the stop had finished and
- * the SIGCHLD was pending on entry to this kill.
- */
- p->signal->group_stop_count = 0;
- p->signal->flags = SIGNAL_STOP_CONTINUED;
- spin_unlock(&p->sighand->siglock);
- do_notify_parent_cldstop(p, CLD_STOPPED);
- spin_lock(&p->sighand->siglock);
- }
- rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending);
+ rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
t = p;
do {
unsigned int state;
rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
-
/*
* If there is a handler for SIGCONT, we must make
* sure that no thread returns to user mode before
* running the handler. With the TIF_SIGPENDING
* flag set, the thread will pause and acquire the
* siglock that we hold now and until we've queued
- * the pending signal.
+ * the pending signal.
*
* Wake up the stopped thread _after_ setting
* TIF_SIGPENDING
*/
- state = TASK_STOPPED;
+ state = __TASK_STOPPED;
if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) {
set_tsk_thread_flag(t, TIF_SIGPENDING);
state |= TASK_INTERRUPTIBLE;
}
wake_up_state(t, state);
+ } while_each_thread(p, t);
- t = next_thread(t);
- } while (t != p);
+ /*
+ * 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 (p->signal->flags & SIGNAL_STOP_STOPPED) {
+ if (why) {
/*
- * We were in fact stopped, and are now continued.
- * Notify the parent with CLD_CONTINUED.
+ * 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().
*/
- p->signal->flags = SIGNAL_STOP_CONTINUED;
- p->signal->group_exit_code = 0;
- spin_unlock(&p->sighand->siglock);
- do_notify_parent_cldstop(p, CLD_CONTINUED);
- spin_lock(&p->sighand->siglock);
+ signal->flags = why | SIGNAL_STOP_CONTINUED;
+ signal->group_stop_count = 0;
+ signal->group_exit_code = 0;
} else {
/*
* We are not stopped, but there could be a stop
* signal in the middle of being processed after
* being removed from the queue. Clear that too.
*/
- p->signal->flags = 0;
+ signal->flags &= ~SIGNAL_STOP_DEQUEUED;
}
- } else if (sig == SIGKILL) {
- /*
- * Make sure that any pending stop signal already dequeued
- * is undone by the wakeup for SIGKILL.
- */
- p->signal->flags = 0;
}
+
+ return !sig_ignored(p, sig, from_ancestor_ns);
}
-static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
- struct sigpending *signals)
+/*
+ * 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 int wants_signal(int sig, struct task_struct *p)
+{
+ if (sigismember(&p->blocked, sig))
+ return 0;
+ if (p->flags & PF_EXITING)
+ return 0;
+ if (sig == SIGKILL)
+ return 1;
+ if (task_is_stopped_or_traced(p))
+ return 0;
+ return task_curr(p) || !signal_pending(p);
+}
+
+static void complete_signal(int sig, struct task_struct *p, int group)
{
- struct sigqueue * q = NULL;
- int ret = 0;
+ struct signal_struct *signal = p->signal;
+ struct task_struct *t;
/*
- * fast-pathed signals for kernel-internal things like SIGSTOP
- * or SIGKILL.
+ * 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 (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. */
-
- q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
- (is_si_special(info) ||
- info->si_code >= 0)));
- if (q) {
- list_add_tail(&q->list, &signals->list);
- switch ((unsigned long) info) {
- case (unsigned long) SEND_SIG_NOINFO:
- q->info.si_signo = sig;
- q->info.si_errno = 0;
- q->info.si_code = SI_USER;
- q->info.si_pid = current->pid;
- q->info.si_uid = current->uid;
- break;
- case (unsigned long) SEND_SIG_PRIV:
- 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);
- break;
- }
- } else if (!is_si_special(info)) {
- if (sig >= SIGRTMIN && info->si_code != SI_USER)
+ if (wants_signal(sig, p))
+ t = p;
+ else if (!group || thread_group_empty(p))
/*
- * Queue overflow, abort. We may abort if the signal was rt
- * and sent by user using something other than kill().
+ * There is just one thread and it does not need to be woken.
+ * It will dequeue unblocked signals before it runs again.
*/
- return -EAGAIN;
+ 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;
}
-out_set:
- sigaddset(&signals->signal, sig);
- return ret;
-}
-
-#define LEGACY_QUEUE(sigptr, sig) \
- (((sig) < SIGRTMIN) && sigismember(&(sigptr)->signal, (sig)))
+ /*
+ * 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_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
+ !sigismember(&t->real_blocked, sig) &&
+ (sig == SIGKILL ||
+ !tracehook_consider_fatal_signal(t, sig))) {
+ /*
+ * 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 {
+ 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 int
-specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+static inline int legacy_queue(struct sigpending *signals, int sig)
+{
+ return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
+}
+
+static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
+ int group, int from_ancestor_ns)
{
- int ret = 0;
+ struct sigpending *pending;
+ struct sigqueue *q;
+ int override_rlimit;
+
+ trace_signal_generate(sig, info, t);
- BUG_ON(!irqs_disabled());
assert_spin_locked(&t->sighand->siglock);
- /* Short-circuit ignored signals. */
- if (sig_ignored(t, sig))
- goto out;
+ if (!prepare_signal(sig, t, from_ancestor_ns))
+ return 0;
- /* Support queueing exactly one non-rt signal, so that we
- can get more detailed information about the cause of
- the signal. */
- if (LEGACY_QUEUE(&t->pending, sig))
- goto out;
+ pending = group ? &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.
+ */
+ if (legacy_queue(pending, sig))
+ return 0;
+ /*
+ * 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 | __GFP_NOTRACK_FALSE_POSITIVE,
+ override_rlimit);
+ if (q) {
+ list_add_tail(&q->list, &pending->list);
+ switch ((unsigned long) info) {
+ case (unsigned long) SEND_SIG_NOINFO:
+ 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 = current_uid();
+ break;
+ case (unsigned long) SEND_SIG_PRIV:
+ 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;
+ }
+ } 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().
+ */
+ trace_signal_overflow_fail(sig, group, info);
+ return -EAGAIN;
+ } else {
+ /*
+ * This is a silent loss of information. We still
+ * send the signal, but the *info bits are lost.
+ */
+ trace_signal_lose_info(sig, group, info);
+ }
+ }
+
+out_set:
+ signalfd_notify(t, sig);
+ sigaddset(&pending->signal, sig);
+ complete_signal(sig, t, group);
+ return 0;
+}
+
+static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
+ int group)
+{
+ 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, group, from_ancestor_ns);
+}
+
+static void print_fatal_signal(struct pt_regs *regs, int signr)
+{
+ printk("%s/%d: potentially unexpected fatal signal %d.\n",
+ current->comm, task_pid_nr(current), signr);
+
+#if defined(__i386__) && !defined(__arch_um__)
+ printk("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;
+ printk("%02x ", insn);
+ }
+ }
+#endif
+ printk("\n");
+ 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, 1);
+}
+
+static int
+specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+{
+ return send_signal(sig, info, t, 0);
+}
+
+int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
+ bool group)
+{
+ unsigned long flags;
+ int ret = -ESRCH;
+
+ if (lock_task_sighand(p, &flags)) {
+ ret = send_signal(sig, info, p, group);
+ unlock_task_sighand(p, &flags);
+ }
- ret = send_signal(sig, info, t, &t->pending);
- if (!ret && !sigismember(&t->blocked, sig))
- signal_wake_up(t, sig == SIGKILL);
-out:
return ret;
}
* 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.
+ * 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)
action->sa.sa_handler = SIG_DFL;
if (blocked) {
sigdelset(&t->blocked, sig);
- recalc_sigpending_tsk(t);
+ recalc_sigpending_and_wake(t);
}
}
+ if (action->sa.sa_handler == SIG_DFL)
+ t->signal->flags &= ~SIGNAL_UNKILLABLE;
ret = specific_send_sig_info(sig, info, t);
spin_unlock_irqrestore(&t->sighand->siglock, flags);
return ret;
}
-void
-force_sig_specific(int sig, struct task_struct *t)
-{
- force_sig_info(sig, SEND_SIG_FORCED, t);
-}
-
-/*
- * 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 int wants_signal(int sig, struct task_struct *p)
-{
- if (sigismember(&p->blocked, sig))
- return 0;
- if (p->flags & PF_EXITING)
- return 0;
- if (sig == SIGKILL)
- return 1;
- if (p->state & (TASK_STOPPED | TASK_TRACED))
- return 0;
- return task_curr(p) || !signal_pending(p);
-}
-
-static void
-__group_complete_signal(int sig, struct task_struct *p)
-{
- 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 (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 = p->signal->curr_target;
- if (t == NULL)
- /* restart balancing at this thread */
- t = p->signal->curr_target = p;
-
- while (!wants_signal(sig, t)) {
- t = next_thread(t);
- if (t == p->signal->curr_target)
- /*
- * No thread needs to be woken.
- * Any eligible threads will see
- * the signal in the queue soon.
- */
- return;
- }
- p->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) && !(p->signal->flags & SIGNAL_GROUP_EXIT) &&
- !sigismember(&t->real_blocked, sig) &&
- (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
- /*
- * 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.
- */
- p->signal->flags = SIGNAL_GROUP_EXIT;
- p->signal->group_exit_code = sig;
- p->signal->group_stop_count = 0;
- t = p;
- do {
- sigaddset(&t->pending.signal, SIGKILL);
- signal_wake_up(t, 1);
- t = next_thread(t);
- } while (t != p);
- return;
- }
-
- /*
- * There will be a core dump. We make all threads other
- * than the chosen one go into a group stop so that nothing
- * happens until it gets scheduled, takes the signal off
- * the shared queue, and does the core dump. This is a
- * little more complicated than strictly necessary, but it
- * keeps the signal state that winds up in the core dump
- * unchanged from the death state, e.g. which thread had
- * the core-dump signal unblocked.
- */
- rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
- rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending);
- p->signal->group_stop_count = 0;
- p->signal->group_exit_task = t;
- t = p;
- do {
- p->signal->group_stop_count++;
- signal_wake_up(t, 0);
- t = next_thread(t);
- } while (t != p);
- wake_up_process(p->signal->group_exit_task);
- 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;
-}
-
-int
-__group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
-{
- int ret = 0;
-
- assert_spin_locked(&p->sighand->siglock);
- handle_stop_signal(sig, p);
-
- /* Short-circuit ignored signals. */
- if (sig_ignored(p, sig))
- return ret;
-
- if (LEGACY_QUEUE(&p->signal->shared_pending, sig))
- /* This is a non-RT signal and we already have one queued. */
- return ret;
-
- /*
- * Put this signal on the shared-pending queue, or fail with EAGAIN.
- * We always use the shared queue for process-wide signals,
- * to avoid several races.
- */
- ret = send_signal(sig, info, p, &p->signal->shared_pending);
- if (unlikely(ret))
- return ret;
-
- __group_complete_signal(sig, p);
- return 0;
-}
-
/*
* Nuke all other threads in the group.
*/
{
struct task_struct *t;
- p->signal->flags = SIGNAL_GROUP_EXIT;
p->signal->group_stop_count = 0;
- if (thread_group_empty(p))
- return;
-
for (t = next_thread(p); t != p; t = next_thread(t)) {
/*
* Don't bother with already dead threads
if (t->exit_state)
continue;
- /*
- * We don't want to notify the parent, since we are
- * killed as part of a thread group due to another
- * thread doing an execve() or similar. So set the
- * exit signal to -1 to allow immediate reaping of
- * the process. But don't detach the thread group
- * leader.
- */
- if (t != p->group_leader)
- t->exit_signal = -1;
-
/* SIGKILL will be handled before any pending SIGSTOP */
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
}
}
-/*
- * Must be called under rcu_read_lock() or with tasklist_lock read-held.
- */
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;
spin_unlock_irqrestore(&sighand->siglock, *flags);
}
+ rcu_read_unlock();
return sighand;
}
+/*
+ * send signal info to all the members of a group
+ * - the caller must hold the RCU read lock at least
+ */
int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
- unsigned long flags;
- int ret;
+ int ret = check_kill_permission(sig, info, p);
- ret = check_kill_permission(sig, info, p);
-
- if (!ret && sig) {
- ret = -ESRCH;
- if (lock_task_sighand(p, &flags)) {
- ret = __group_send_sig_info(sig, info, p);
- unlock_task_sighand(p, &flags);
- }
- }
+ if (!ret && sig)
+ ret = do_send_sig_info(sig, info, p, true);
return ret;
}
/*
- * kill_pgrp_info() sends a signal to a process group: this is what the tty
+ * __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;
return success ? 0 : retval;
}
-int kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
-{
- int retval;
-
- read_lock(&tasklist_lock);
- retval = __kill_pgrp_info(sig, info, pgrp);
- read_unlock(&tasklist_lock);
-
- return retval;
-}
-
-int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
-{
- if (pgrp <= 0)
- return -EINVAL;
-
- return __kill_pgrp_info(sig, info, find_pid(pgrp));
-}
-
-int
-kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
-{
- int retval;
-
- read_lock(&tasklist_lock);
- retval = __kill_pg_info(sig, info, pgrp);
- read_unlock(&tasklist_lock);
-
- return retval;
-}
-
int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
{
- int error;
- int acquired_tasklist_lock = 0;
+ int error = -ESRCH;
struct task_struct *p;
rcu_read_lock();
- if (unlikely(sig_needs_tasklist(sig))) {
- read_lock(&tasklist_lock);
- acquired_tasklist_lock = 1;
- }
+retry:
p = pid_task(pid, PIDTYPE_PID);
- error = -ESRCH;
- if (p)
+ if (p) {
error = group_send_sig_info(sig, info, p);
- if (unlikely(acquired_tasklist_lock))
- read_unlock(&tasklist_lock);
+ if (unlikely(error == -ESRCH))
+ /*
+ * 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.
+ */
+ goto retry;
+ }
rcu_read_unlock();
+
return error;
}
-static int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+int
+kill_proc_info(int sig, struct siginfo *info, pid_t pid)
{
int error;
rcu_read_lock();
- error = kill_pid_info(sig, info, find_pid(pid));
+ error = kill_pid_info(sig, info, find_vpid(pid));
rcu_read_unlock();
return error;
}
{
int ret = -EINVAL;
struct task_struct *p;
+ const struct cred *pcred;
+ unsigned long flags;
if (!valid_signal(sig))
return ret;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
p = pid_task(pid, PIDTYPE_PID);
if (!p) {
ret = -ESRCH;
goto out_unlock;
}
- if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
- && (euid != p->suid) && (euid != p->uid)
- && (uid != p->suid) && (uid != p->uid)) {
+ pcred = __task_cred(p);
+ if (si_fromuser(info) &&
+ euid != pcred->suid && euid != pcred->uid &&
+ uid != pcred->suid && uid != pcred->uid) {
ret = -EPERM;
goto out_unlock;
}
ret = security_task_kill(p, info, sig, secid);
if (ret)
goto out_unlock;
- if (sig && p->sighand) {
- unsigned long flags;
- spin_lock_irqsave(&p->sighand->siglock, flags);
- ret = __group_send_sig_info(sig, info, p);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
+
+ if (sig) {
+ if (lock_task_sighand(p, &flags)) {
+ ret = __send_signal(sig, info, p, 1, 0);
+ unlock_task_sighand(p, &flags);
+ } else
+ ret = -ESRCH;
}
out_unlock:
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
* is probably wrong. Should make it like BSD or SYSV.
*/
-static int kill_something_info(int sig, struct siginfo *info, int pid)
+static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
{
- if (!pid) {
- return kill_pg_info(sig, info, process_group(current));
- } else if (pid == -1) {
+ int ret;
+
+ if (pid > 0) {
+ rcu_read_lock();
+ ret = kill_pid_info(sig, info, find_vpid(pid));
+ rcu_read_unlock();
+ return ret;
+ }
+
+ 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;
- read_lock(&tasklist_lock);
for_each_process(p) {
- if (p->pid > 1 && p->tgid != current->tgid) {
+ if (task_pid_vnr(p) > 1 &&
+ !same_thread_group(p, current)) {
int err = group_send_sig_info(sig, info, p);
++count;
if (err != -EPERM)
retval = err;
}
}
- read_unlock(&tasklist_lock);
- return count ? retval : -ESRCH;
- } else if (pid < 0) {
- return kill_pg_info(sig, info, -pid);
- } else {
- return kill_proc_info(sig, info, pid);
+ ret = count ? retval : -ESRCH;
}
+ read_unlock(&tasklist_lock);
+
+ return ret;
}
/*
* These are for backward compatibility with the rest of the kernel source.
*/
-/*
- * These two are the most common entry points. They send a signal
- * just to the specific thread.
- */
int
send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
- int ret;
- unsigned long flags;
-
/*
* 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;
- /*
- * We need the tasklist lock even for the specific
- * thread case (when we don't need to follow the group
- * lists) in order to avoid races with "p->sighand"
- * going away or changing from under us.
- */
- read_lock(&tasklist_lock);
- spin_lock_irqsave(&p->sighand->siglock, flags);
- ret = specific_send_sig_info(sig, info, p);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
- read_unlock(&tasklist_lock);
- return ret;
+ return do_send_sig_info(sig, info, p, false);
}
#define __si_special(priv) \
return send_sig_info(sig, __si_special(priv), p);
}
-/*
- * This is the entry point for "process-wide" signals.
- * They will go to an appropriate thread in the thread group.
- */
-int
-send_group_sig_info(int sig, struct siginfo *info, struct task_struct *p)
-{
- int ret;
- read_lock(&tasklist_lock);
- ret = group_send_sig_info(sig, info, p);
- read_unlock(&tasklist_lock);
- return ret;
-}
-
void
force_sig(int sig, struct task_struct *p)
{
int kill_pgrp(struct pid *pid, int sig, int priv)
{
- return kill_pgrp_info(sig, __si_special(priv), pid);
-}
-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);
+ int ret;
-int
-kill_pg(pid_t pgrp, int sig, int priv)
-{
- return kill_pg_info(sig, __si_special(priv), pgrp);
+ 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_proc(pid_t pid, int sig, int priv)
+int kill_pid(struct pid *pid, int sig, int priv)
{
- return kill_proc_info(sig, __si_special(priv), pid);
+ 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
+ * 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;
+ struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
- if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0)))
+ if (q)
q->flags |= SIGQUEUE_PREALLOC;
- return(q);
+
+ return q;
}
void sigqueue_free(struct sigqueue *q)
{
unsigned long flags;
+ spinlock_t *lock = ¤t->sighand->siglock;
+
BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
/*
- * If the signal is still pending remove it from the
- * pending queue.
+ * We must hold ->siglock while testing q->list
+ * to serialize with collect_signal() or with
+ * __exit_signal()->flush_sigqueue().
*/
- if (unlikely(!list_empty(&q->list))) {
- spinlock_t *lock = ¤t->sighand->siglock;
- read_lock(&tasklist_lock);
- spin_lock_irqsave(lock, flags);
- if (!list_empty(&q->list))
- list_del_init(&q->list);
- spin_unlock_irqrestore(lock, flags);
- read_unlock(&tasklist_lock);
- }
+ spin_lock_irqsave(lock, flags);
q->flags &= ~SIGQUEUE_PREALLOC;
- __sigqueue_free(q);
-}
-
-int send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
-{
- unsigned long flags;
- int ret = 0;
-
- BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
-
/*
- * The rcu based delayed sighand destroy makes it possible to
- * run this without tasklist lock held. The task struct itself
- * cannot go away as create_timer did get_task_struct().
- *
- * We return -1, when the task is marked exiting, so
- * posix_timer_event can redirect it to the group leader
+ * If it is queued it will be freed when dequeued,
+ * like the "regular" sigqueue.
*/
- rcu_read_lock();
-
- if (!likely(lock_task_sighand(p, &flags))) {
- ret = -1;
- goto out_err;
- }
-
- 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++;
- goto out;
- }
- /* Short-circuit ignored signals. */
- if (sig_ignored(p, sig)) {
- ret = 1;
- goto out;
- }
-
- list_add_tail(&q->list, &p->pending.list);
- sigaddset(&p->pending.signal, sig);
- if (!sigismember(&p->blocked, sig))
- signal_wake_up(p, sig == SIGKILL);
-
-out:
- unlock_task_sighand(p, &flags);
-out_err:
- rcu_read_unlock();
+ if (!list_empty(&q->list))
+ q = NULL;
+ spin_unlock_irqrestore(lock, flags);
- return ret;
+ if (q)
+ __sigqueue_free(q);
}
-int
-send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
+int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
{
+ int sig = q->info.si_signo;
+ struct sigpending *pending;
unsigned long flags;
- int ret = 0;
+ int ret;
BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
- read_lock(&tasklist_lock);
- /* Since it_lock is held, p->sighand cannot be NULL. */
- spin_lock_irqsave(&p->sighand->siglock, flags);
- handle_stop_signal(sig, p);
+ ret = -1;
+ if (!likely(lock_task_sighand(t, &flags)))
+ goto ret;
- /* Short-circuit ignored signals. */
- if (sig_ignored(p, sig)) {
- ret = 1;
+ ret = 1; /* the signal is ignored */
+ if (!prepare_signal(sig, t, 0))
goto out;
- }
+ ret = 0;
if (unlikely(!list_empty(&q->list))) {
/*
* If an SI_TIMER entry is already queue just increment
- * the overrun count. Other uses should not try to
- * send the signal multiple times.
+ * the overrun count.
*/
BUG_ON(q->info.si_code != SI_TIMER);
q->info.si_overrun++;
goto out;
- }
-
- /*
- * Put this signal on the shared-pending queue.
- * We always use the shared queue for process-wide signals,
- * to avoid several races.
- */
- list_add_tail(&q->list, &p->signal->shared_pending.list);
- sigaddset(&p->signal->shared_pending.signal, sig);
+ }
+ q->info.si_overrun = 0;
- __group_complete_signal(sig, p);
+ signalfd_notify(t, sig);
+ pending = group ? &t->signal->shared_pending : &t->pending;
+ list_add_tail(&q->list, &pending->list);
+ sigaddset(&pending->signal, sig);
+ complete_signal(sig, t, group);
out:
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
- read_unlock(&tasklist_lock);
+ unlock_task_sighand(t, &flags);
+ret:
return ret;
}
/*
- * Wake up any threads in the parent blocked in wait* syscalls.
- */
-static inline void __wake_up_parent(struct task_struct *p,
- struct task_struct *parent)
-{
- wake_up_interruptible_sync(&parent->signal->wait_chldexit);
-}
-
-/*
* Let a parent know about the death of a child.
* For a stopped/continued status change, use do_notify_parent_cldstop instead.
+ *
+ * Returns -1 if our parent ignored us and so we've switched to
+ * self-reaping, or else @sig.
*/
-
-void do_notify_parent(struct task_struct *tsk, int sig)
+int do_notify_parent(struct task_struct *tsk, int sig)
{
struct siginfo info;
unsigned long flags;
struct sighand_struct *psig;
+ int ret = sig;
BUG_ON(sig == -1);
/* do_notify_parent_cldstop should have been called instead. */
- BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED));
+ BUG_ON(task_is_stopped_or_traced(tsk));
- BUG_ON(!tsk->ptrace &&
+ BUG_ON(!task_ptrace(tsk) &&
(tsk->group_leader != tsk || !thread_group_empty(tsk)));
info.si_signo = sig;
info.si_errno = 0;
- info.si_pid = tsk->pid;
- info.si_uid = tsk->uid;
+ /*
+ * we are under tasklist_lock here so our parent is tied to
+ * us and cannot exit and release its namespace.
+ *
+ * the only it can is to switch its nsproxy with sys_unshare,
+ * bu uncharing pid namespaces is not allowed, so we'll always
+ * see relevant namespace
+ *
+ * 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, tsk->parent->nsproxy->pid_ns);
+ info.si_uid = __task_cred(tsk)->uid;
+ rcu_read_unlock();
- /* FIXME: find out whether or not this is supposed to be c*time. */
- info.si_utime = cputime_to_jiffies(cputime_add(tsk->utime,
- tsk->signal->utime));
- info.si_stime = cputime_to_jiffies(cputime_add(tsk->stime,
- tsk->signal->stime));
+ info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime,
+ tsk->signal->utime));
+ info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime,
+ tsk->signal->stime));
info.si_status = tsk->exit_code & 0x7f;
if (tsk->exit_code & 0x80)
psig = tsk->parent->sighand;
spin_lock_irqsave(&psig->siglock, flags);
- if (!tsk->ptrace && sig == SIGCHLD &&
+ if (!task_ptrace(tsk) && sig == SIGCHLD &&
(psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
(psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
/*
* is implementation-defined: we do (if you don't want
* it, just use SIG_IGN instead).
*/
- tsk->exit_signal = -1;
+ ret = tsk->exit_signal = -1;
if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
- sig = 0;
+ sig = -1;
}
if (valid_signal(sig) && sig > 0)
__group_send_sig_info(sig, &info, tsk->parent);
__wake_up_parent(tsk, tsk->parent);
spin_unlock_irqrestore(&psig->siglock, flags);
+
+ return ret;
}
static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
struct task_struct *parent;
struct sighand_struct *sighand;
- if (tsk->ptrace & PT_PTRACED)
+ if (task_ptrace(tsk))
parent = tsk->parent;
else {
tsk = tsk->group_leader;
info.si_signo = SIGCHLD;
info.si_errno = 0;
- info.si_pid = tsk->pid;
- info.si_uid = tsk->uid;
+ /*
+ * see comment in do_notify_parent() abot the following 3 lines
+ */
+ rcu_read_lock();
+ info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
+ info.si_uid = __task_cred(tsk)->uid;
+ rcu_read_unlock();
- /* FIXME: find out whether or not this is supposed to be c*time. */
- info.si_utime = cputime_to_jiffies(tsk->utime);
- info.si_stime = cputime_to_jiffies(tsk->stime);
+ info.si_utime = cputime_to_clock_t(tsk->utime);
+ info.si_stime = cputime_to_clock_t(tsk->stime);
info.si_code = why;
switch (why) {
static inline int may_ptrace_stop(void)
{
- if (!likely(current->ptrace & PT_PTRACED))
- return 0;
-
- if (unlikely(current->parent == current->real_parent &&
- (current->ptrace & PT_ATTACHED)))
- return 0;
-
- if (unlikely(current->signal == current->parent->signal) &&
- unlikely(current->signal->flags & SIGNAL_GROUP_EXIT))
+ if (!likely(task_ptrace(current)))
return 0;
-
/*
* 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_waiters != 0. Otherwise it
+ * ->siglock we must see ->core_state != NULL. Otherwise it
* is safe to enter schedule().
*/
- if (unlikely(current->mm->core_waiters) &&
+ if (unlikely(current->mm->core_state) &&
unlikely(current->mm == current->parent->mm))
return 0;
}
/*
+ * Return nonzero if there is a SIGKILL that should be waking us up.
+ * Called with the siglock held.
+ */
+static int 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.
* 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 leave nostop_code in current->exit_code.
+ * 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 nostop_code, siginfo_t *info)
+static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
{
+ 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;
+ }
+
/*
* If there is a group stop in progress,
* we must participate in the bookkeeping.
current->exit_code = exit_code;
/* Let the debugger run. */
- set_current_state(TASK_TRACED);
+ __set_current_state(TASK_TRACED);
spin_unlock_irq(¤t->sighand->siglock);
- try_to_freeze();
read_lock(&tasklist_lock);
if (may_ptrace_stop()) {
do_notify_parent_cldstop(current, CLD_TRAPPED);
+ /*
+ * 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();
schedule();
} else {
/*
* By the time we got the lock, our tracer went away.
- * Don't stop here.
+ * Don't drop the lock yet, another tracer may come.
*/
+ __set_current_state(TASK_RUNNING);
+ if (clear_code)
+ current->exit_code = 0;
read_unlock(&tasklist_lock);
- set_current_state(TASK_RUNNING);
- current->exit_code = nostop_code;
}
/*
+ * While in TASK_TRACED, we were considered "frozen enough".
+ * Now that we woke up, it's crucial if we're supposed to be
+ * frozen that we freeze now before running anything substantial.
+ */
+ try_to_freeze();
+
+ /*
* 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.
/*
* 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();
+ recalc_sigpending_tsk(current);
}
void ptrace_notify(int exit_code)
memset(&info, 0, sizeof info);
info.si_signo = SIGTRAP;
info.si_code = exit_code;
- info.si_pid = current->pid;
- info.si_uid = current->uid;
+ info.si_pid = task_pid_vnr(current);
+ info.si_uid = current_uid();
/* Let the debugger run. */
spin_lock_irq(¤t->sighand->siglock);
- ptrace_stop(exit_code, 0, &info);
+ ptrace_stop(exit_code, 1, &info);
spin_unlock_irq(¤t->sighand->siglock);
}
-static void
-finish_stop(int stop_count)
-{
- /*
- * 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. When ptraced, every thread reports itself.
- */
- if (stop_count == 0 || (current->ptrace & PT_PTRACED)) {
- read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current, CLD_STOPPED);
- read_unlock(&tasklist_lock);
- }
-
- schedule();
- /*
- * Now we don't run again until continued.
- */
- current->exit_code = 0;
-}
-
/*
* This performs the stopping for SIGSTOP and other stop signals.
* We have to stop all threads in the thread group.
static int do_signal_stop(int signr)
{
struct signal_struct *sig = current->signal;
- int stop_count;
+ int notify;
- if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED))
- return 0;
+ if (!sig->group_stop_count) {
+ struct task_struct *t;
- if (sig->group_stop_count > 0) {
- /*
- * There is a group stop in progress. We don't need to
- * start another one.
- */
- stop_count = --sig->group_stop_count;
- } else {
+ if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
+ unlikely(signal_group_exit(sig)))
+ return 0;
/*
* There is no group stop already in progress.
* We must initiate one now.
*/
- struct task_struct *t;
-
sig->group_exit_code = signr;
- stop_count = 0;
+ sig->group_stop_count = 1;
for (t = next_thread(current); t != current; t = next_thread(t))
/*
* Setting state to TASK_STOPPED for a group
* stop is always done with the siglock held,
* so this check has no races.
*/
- if (!t->exit_state &&
- !(t->state & (TASK_STOPPED|TASK_TRACED))) {
- stop_count++;
+ if (!(t->flags & PF_EXITING) &&
+ !task_is_stopped_or_traced(t)) {
+ sig->group_stop_count++;
signal_wake_up(t, 0);
}
- sig->group_stop_count = stop_count;
+ }
+ /*
+ * 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. When ptraced, every thread reports itself.
+ */
+ notify = sig->group_stop_count == 1 ? CLD_STOPPED : 0;
+ notify = tracehook_notify_jctl(notify, CLD_STOPPED);
+ /*
+ * tracehook_notify_jctl() can drop and reacquire siglock, so
+ * we keep ->group_stop_count != 0 before the call. If SIGCONT
+ * or SIGKILL comes in between ->group_stop_count == 0.
+ */
+ if (sig->group_stop_count) {
+ if (!--sig->group_stop_count)
+ sig->flags = SIGNAL_STOP_STOPPED;
+ current->exit_code = sig->group_exit_code;
+ __set_current_state(TASK_STOPPED);
+ }
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ if (notify) {
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(current, notify);
+ read_unlock(&tasklist_lock);
}
- if (stop_count == 0)
- sig->flags = SIGNAL_STOP_STOPPED;
- current->exit_code = sig->group_exit_code;
- __set_current_state(TASK_STOPPED);
+ /* Now we don't run again until woken by SIGCONT or SIGKILL */
+ do {
+ schedule();
+ } while (try_to_freeze());
+
+ tracehook_finish_jctl();
+ current->exit_code = 0;
- spin_unlock_irq(¤t->sighand->siglock);
- finish_stop(stop_count);
return 1;
}
-/*
- * Do appropriate magic when group_stop_count > 0.
- * We return nonzero if we stopped, after releasing the siglock.
- * We return zero if we still hold the siglock and should look
- * for another signal without checking group_stop_count again.
- */
-static int handle_group_stop(void)
+static int ptrace_signal(int signr, siginfo_t *info,
+ struct pt_regs *regs, void *cookie)
{
- int stop_count;
+ if (!task_ptrace(current))
+ return signr;
- if (current->signal->group_exit_task == current) {
- /*
- * Group stop is so we can do a core dump,
- * We are the initiating thread, so get on with it.
- */
- current->signal->group_exit_task = NULL;
- return 0;
+ ptrace_signal_deliver(regs, cookie);
+
+ /* Let the debugger run. */
+ ptrace_stop(signr, 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) {
+ info->si_signo = signr;
+ info->si_errno = 0;
+ info->si_code = SI_USER;
+ info->si_pid = task_pid_vnr(current->parent);
+ info->si_uid = task_uid(current->parent);
}
- if (current->signal->flags & SIGNAL_GROUP_EXIT)
- /*
- * Group stop is so another thread can do a core dump,
- * or else we are racing against a death signal.
- * Just punt the stop so we can get the next signal.
- */
- return 0;
+ /* If the (new) signal is now blocked, requeue it. */
+ if (sigismember(¤t->blocked, signr)) {
+ specific_send_sig_info(signr, info, current);
+ signr = 0;
+ }
- /*
- * There is a group stop in progress. We stop
- * without any associated signal being in our queue.
- */
- stop_count = --current->signal->group_stop_count;
- if (stop_count == 0)
- current->signal->flags = SIGNAL_STOP_STOPPED;
- current->exit_code = current->signal->group_exit_code;
- set_current_state(TASK_STOPPED);
- spin_unlock_irq(¤t->sighand->siglock);
- finish_stop(stop_count);
- return 1;
+ return signr;
}
int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
struct pt_regs *regs, void *cookie)
{
- sigset_t *mask = ¤t->blocked;
- int signr = 0;
+ struct sighand_struct *sighand = current->sighand;
+ struct signal_struct *signal = current->signal;
+ int signr;
+relock:
+ /*
+ * We'll jump back here after any time we were stopped in TASK_STOPPED.
+ * While in TASK_STOPPED, we were considered "frozen enough".
+ * Now that we woke up, it's crucial if we're supposed to be
+ * frozen that we freeze now before running anything substantial.
+ */
try_to_freeze();
-relock:
- spin_lock_irq(¤t->sighand->siglock);
+ 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 = (signal->flags & SIGNAL_STOP_CONTINUED)
+ ? CLD_CONTINUED : CLD_STOPPED;
+ signal->flags &= ~SIGNAL_CLD_MASK;
+
+ why = tracehook_notify_jctl(why, CLD_CONTINUED);
+ spin_unlock_irq(&sighand->siglock);
+
+ if (why) {
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(current->group_leader, why);
+ read_unlock(&tasklist_lock);
+ }
+ goto relock;
+ }
+
for (;;) {
struct k_sigaction *ka;
-
- if (unlikely(current->signal->group_stop_count > 0) &&
- handle_group_stop())
+ /*
+ * Tracing can induce an artifical signal and choose sigaction.
+ * The return value in @signr determines the default action,
+ * but @info->si_signo is the signal number we will report.
+ */
+ signr = tracehook_get_signal(current, regs, info, return_ka);
+ if (unlikely(signr < 0))
goto relock;
+ if (unlikely(signr != 0))
+ ka = return_ka;
+ else {
+ if (unlikely(signal->group_stop_count > 0) &&
+ do_signal_stop(0))
+ goto relock;
- signr = dequeue_signal(current, mask, info);
-
- if (!signr)
- break; /* will return 0 */
-
- if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
- ptrace_signal_deliver(regs, cookie);
-
- /* Let the debugger run. */
- ptrace_stop(signr, signr, info);
-
- /* We're back. Did the debugger cancel the sig? */
- signr = current->exit_code;
- if (signr == 0)
- continue;
+ signr = dequeue_signal(current, ¤t->blocked,
+ info);
- current->exit_code = 0;
+ if (!signr)
+ break; /* will return 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) {
- info->si_signo = signr;
- info->si_errno = 0;
- info->si_code = SI_USER;
- info->si_pid = current->parent->pid;
- info->si_uid = current->parent->uid;
+ if (signr != SIGKILL) {
+ signr = ptrace_signal(signr, info,
+ regs, cookie);
+ if (!signr)
+ continue;
}
- /* If the (new) signal is now blocked, requeue it. */
- if (sigismember(¤t->blocked, signr)) {
- specific_send_sig_info(signr, info, current);
- continue;
- }
+ ka = &sighand->action[signr-1];
}
- ka = ¤t->sighand->action[signr-1];
+ /* Trace actually delivered signals. */
+ trace_signal_deliver(signr, info, ka);
+
if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
continue;
if (ka->sa.sa_handler != SIG_DFL) {
continue;
/*
- * Init of a pid space gets no signals it doesn't want from
- * within that pid space. It can of course get signals from
- * its parent pid space.
+ * 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 (current == child_reaper(current))
+ if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
+ !sig_kernel_only(signr))
continue;
if (sig_kernel_stop(signr)) {
* We need to check for that and bail out if necessary.
*/
if (signr != SIGSTOP) {
- spin_unlock_irq(¤t->sighand->siglock);
+ spin_unlock_irq(&sighand->siglock);
/* signals can be posted during this window */
- if (is_orphaned_pgrp(process_group(current)))
+ if (is_current_pgrp_orphaned())
goto relock;
- spin_lock_irq(¤t->sighand->siglock);
+ spin_lock_irq(&sighand->siglock);
}
- if (likely(do_signal_stop(signr))) {
+ if (likely(do_signal_stop(info->si_signo))) {
/* It released the siglock. */
goto relock;
}
continue;
}
- spin_unlock_irq(¤t->sighand->siglock);
+ 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(regs, info->si_signo);
/*
* If it was able to dump core, this kills all
* other threads in the group and synchronizes with
* first and our do_group_exit call below will use
* that value and ignore the one we pass it.
*/
- do_coredump((long)signr, signr, regs);
+ do_coredump(info->si_signo, info->si_signo, regs);
}
/*
* Death signals, no core dump.
*/
- do_group_exit(signr);
+ do_group_exit(info->si_signo);
/* NOTREACHED */
}
- spin_unlock_irq(¤t->sighand->siglock);
+ spin_unlock_irq(&sighand->siglock);
return signr;
}
+void exit_signals(struct task_struct *tsk)
+{
+ int group_stop = 0;
+ struct task_struct *t;
+
+ if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
+ tsk->flags |= PF_EXITING;
+ 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;
+ if (!signal_pending(tsk))
+ goto out;
+
+ /* It could be that __group_complete_signal() choose us to
+ * notify about group-wide signal. Another thread should be
+ * woken now to take the signal since we will not.
+ */
+ for (t = tsk; (t = next_thread(t)) != tsk; )
+ if (!signal_pending(t) && !(t->flags & PF_EXITING))
+ recalc_sigpending_and_wake(t);
+
+ if (unlikely(tsk->signal->group_stop_count) &&
+ !--tsk->signal->group_stop_count) {
+ tsk->signal->flags = SIGNAL_STOP_STOPPED;
+ group_stop = tracehook_notify_jctl(CLD_STOPPED, CLD_STOPPED);
+ }
+out:
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ if (unlikely(group_stop)) {
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(tsk, 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(kill_pg);
-EXPORT_SYMBOL(kill_proc);
-EXPORT_SYMBOL(ptrace_notify);
EXPORT_SYMBOL(send_sig);
EXPORT_SYMBOL(send_sig_info);
EXPORT_SYMBOL(sigprocmask);
* System call entry points.
*/
-asmlinkage long sys_restart_syscall(void)
+SYSCALL_DEFINE0(restart_syscall)
{
struct restart_block *restart = ¤t_thread_info()->restart_block;
return restart->fn(restart);
return error;
}
-asmlinkage long
-sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize)
+SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set,
+ sigset_t __user *, oset, size_t, sigsetsize)
{
int error = -EINVAL;
sigset_t old_set, new_set;
return error;
}
-asmlinkage long
-sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize)
+SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize)
{
return do_sigpending(set, sigsetsize);
}
/*
* If you change siginfo_t structure, please be sure
* this code is fixed accordingly.
+ * Please remember to update the signalfd_copyinfo() function
+ * inside fs/signalfd.c too, in case siginfo_t changes.
* It should never copy any pad contained in the structure
* to avoid security leaks, but must copy the generic
* 3 ints plus the relevant union member.
#endif
-asmlinkage long
-sys_rt_sigtimedwait(const sigset_t __user *uthese,
- siginfo_t __user *uinfo,
- const struct timespec __user *uts,
- size_t sigsetsize)
+SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
+ siginfo_t __user *, uinfo, const struct timespec __user *, uts,
+ size_t, sigsetsize)
{
int ret, sig;
sigset_t these;
return ret;
}
-asmlinkage long
-sys_kill(int pid, int sig)
+SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
{
struct siginfo info;
info.si_signo = sig;
info.si_errno = 0;
info.si_code = SI_USER;
- info.si_pid = current->tgid;
- info.si_uid = current->uid;
+ info.si_pid = task_tgid_vnr(current);
+ info.si_uid = current_uid();
return kill_something_info(sig, &info, pid);
}
-static int do_tkill(int tgid, int pid, int sig)
+static int
+do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
{
- int error;
- struct siginfo info;
struct task_struct *p;
+ int error = -ESRCH;
- error = -ESRCH;
- info.si_signo = sig;
- info.si_errno = 0;
- info.si_code = SI_TKILL;
- info.si_pid = current->tgid;
- info.si_uid = current->uid;
-
- read_lock(&tasklist_lock);
- p = find_task_by_pid(pid);
- if (p && (tgid <= 0 || p->tgid == tgid)) {
- error = check_kill_permission(sig, &info, p);
+ 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 && p->sighand) {
- spin_lock_irq(&p->sighand->siglock);
- handle_stop_signal(sig, p);
- error = specific_send_sig_info(sig, &info, p);
- spin_unlock_irq(&p->sighand->siglock);
+ if (!error && sig) {
+ error = do_send_sig_info(sig, info, p, false);
+ /*
+ * 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;
}
}
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
return error;
}
+static int do_tkill(pid_t tgid, pid_t pid, int sig)
+{
+ struct 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 = 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
+ * 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.
*/
-asmlinkage long sys_tgkill(int tgid, int pid, int sig)
+SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
{
/* This is only valid for single tasks */
if (pid <= 0 || tgid <= 0)
/*
* Send a signal to only one task, even if it's a CLONE_THREAD task.
*/
-asmlinkage long
-sys_tkill(int pid, int sig)
+SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
{
/* This is only valid for single tasks */
if (pid <= 0)
return do_tkill(0, pid, sig);
}
-asmlinkage long
-sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo)
+SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
+ siginfo_t __user *, uinfo)
{
siginfo_t info;
return kill_proc_info(sig, &info, pid);
}
+long 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(), which adds source info. */
+ if (info->si_code >= 0)
+ 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);
+}
+
int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
{
+ struct task_struct *t = current;
struct k_sigaction *k;
sigset_t mask;
if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
return -EINVAL;
- k = ¤t->sighand->action[sig-1];
+ k = &t->sighand->action[sig-1];
spin_lock_irq(¤t->sighand->siglock);
- if (signal_pending(current)) {
- /*
- * If there might be a fatal signal pending on multiple
- * threads, make sure we take it before changing the action.
- */
- spin_unlock_irq(¤t->sighand->siglock);
- return -ERESTARTNOINTR;
- }
-
if (oact)
*oact = *k;
* (for example, SIGCHLD), shall cause the pending signal to
* be discarded, whether or not it is blocked"
*/
- if (act->sa.sa_handler == SIG_IGN ||
- (act->sa.sa_handler == SIG_DFL && sig_kernel_ignore(sig))) {
- struct task_struct *t = current;
+ if (sig_handler_ignored(sig_handler(t, sig), sig)) {
sigemptyset(&mask);
sigaddset(&mask, sig);
rm_from_queue_full(&mask, &t->signal->shared_pending);
do {
rm_from_queue_full(&mask, &t->pending);
- recalc_sigpending_tsk(t);
t = next_thread(t);
} while (t != current);
}
stack_t oss;
int error;
- if (uoss) {
- oss.ss_sp = (void __user *) current->sas_ss_sp;
- oss.ss_size = current->sas_ss_size;
- oss.ss_flags = sas_ss_flags(sp);
- }
+ oss.ss_sp = (void __user *) current->sas_ss_sp;
+ oss.ss_size = current->sas_ss_size;
+ oss.ss_flags = sas_ss_flags(sp);
if (uss) {
void __user *ss_sp;
int ss_flags;
error = -EFAULT;
- if (!access_ok(VERIFY_READ, uss, sizeof(*uss))
- || __get_user(ss_sp, &uss->ss_sp)
- || __get_user(ss_flags, &uss->ss_flags)
- || __get_user(ss_size, &uss->ss_size))
+ if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
+ goto out;
+ error = __get_user(ss_sp, &uss->ss_sp) |
+ __get_user(ss_flags, &uss->ss_flags) |
+ __get_user(ss_size, &uss->ss_size);
+ if (error)
goto out;
error = -EPERM;
current->sas_ss_size = ss_size;
}
+ error = 0;
if (uoss) {
error = -EFAULT;
- if (copy_to_user(uoss, &oss, sizeof(oss)))
+ if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
goto out;
+ error = __put_user(oss.ss_sp, &uoss->ss_sp) |
+ __put_user(oss.ss_size, &uoss->ss_size) |
+ __put_user(oss.ss_flags, &uoss->ss_flags);
}
- error = 0;
out:
return error;
}
#ifdef __ARCH_WANT_SYS_SIGPENDING
-asmlinkage long
-sys_sigpending(old_sigset_t __user *set)
+SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
{
return do_sigpending(set, sizeof(*set));
}
/* Some platforms have their own version with special arguments others
support only sys_rt_sigprocmask. */
-asmlinkage long
-sys_sigprocmask(int how, old_sigset_t __user *set, old_sigset_t __user *oset)
+SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set,
+ old_sigset_t __user *, oset)
{
int error;
old_sigset_t old_set, new_set;
#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
#ifdef __ARCH_WANT_SYS_RT_SIGACTION
-asmlinkage long
-sys_rt_sigaction(int sig,
- const struct sigaction __user *act,
- struct sigaction __user *oact,
- size_t sigsetsize)
+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 = -EINVAL;
/*
* For backwards compatibility. Functionality superseded by sigprocmask.
*/
-asmlinkage long
-sys_sgetmask(void)
+SYSCALL_DEFINE0(sgetmask)
{
/* SMP safe */
return current->blocked.sig[0];
}
-asmlinkage long
-sys_ssetmask(int newmask)
+SYSCALL_DEFINE1(ssetmask, int, newmask)
{
int old;
/*
* For backwards compatibility. Functionality superseded by sigaction.
*/
-asmlinkage unsigned long
-sys_signal(int sig, __sighandler_t handler)
+SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
{
struct k_sigaction new_sa, old_sa;
int ret;
#ifdef __ARCH_WANT_SYS_PAUSE
-asmlinkage long
-sys_pause(void)
+SYSCALL_DEFINE0(pause)
{
current->state = TASK_INTERRUPTIBLE;
schedule();
#endif
#ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
-asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
+SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
{
sigset_t newset;
current->state = TASK_INTERRUPTIBLE;
schedule();
- set_thread_flag(TIF_RESTORE_SIGMASK);
+ set_restore_sigmask();
return -ERESTARTNOHAND;
}
#endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */
void __init signals_init(void)
{
- sigqueue_cachep =
- kmem_cache_create("sigqueue",
- sizeof(struct sigqueue),
- __alignof__(struct sigqueue),
- SLAB_PANIC, NULL, NULL);
+ sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
}