* to allow signals to be sent reliably.
*/
-#include <linux/config.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/security.h>
-#include <linux/ptrace.h>
+#include <linux/syscalls.h>
+#include <linux/tracehook.h>
+#include <linux/signal.h>
+#include <linux/capability.h>
+#include <linux/freezer.h>
+#include <linux/pid_namespace.h>
+#include <linux/nsproxy.h>
+#include <linux/vs_context.h>
+#include <linux/vs_pid.h>
+
#include <asm/param.h>
#include <asm/uaccess.h>
+#include <asm/unistd.h>
#include <asm/siginfo.h>
+#include "audit.h" /* audit_signal_info() */
/*
* SLAB caches for signal bits.
*/
-static kmem_cache_t *sigqueue_cachep;
-
-atomic_t nr_queued_signals;
-int max_queued_signals = 1024;
+static struct kmem_cache *sigqueue_cachep;
/*
* In POSIX a signal is sent either to a specific thread (Linux task)
#define sig_kernel_stop(sig) \
(((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_STOP_MASK))
+#define sig_needs_tasklist(sig) ((sig) == SIGCONT)
+
#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))
(!T(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
(t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
-#define sig_avoid_stop_race() \
- (sigtestsetmask(¤t->pending.signal, M(SIGCONT) | M(SIGKILL)) || \
- sigtestsetmask(¤t->signal->shared_pending.signal, \
- M(SIGCONT) | M(SIGKILL)))
-
static int sig_ignored(struct task_struct *t, int sig)
{
- void * handler;
-
- /*
- * Tracers always want to know about signals..
- */
- if (t->ptrace & PT_PTRACED)
- return 0;
+ void __user * handler;
/*
* Blocked signals are never ignored, since the
/* 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 (handler != SIG_IGN &&
+ (handler != SIG_DFL || !sig_kernel_ignore(sig)))
+ return 0;
+
+ /* It's ignored, we can short-circuit unless a debugger wants it. */
+ return !tracehook_consider_ignored_signal(t, sig, handler);
}
/*
fastcall void 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) ||
+ tracehook_induce_sigpending(t))
set_tsk_thread_flag(t, TIF_SIGPENDING);
else
clear_tsk_thread_flag(t, TIF_SIGPENDING);
return sig;
}
-struct sigqueue *__sigqueue_alloc(void)
+static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
+ int override_rlimit)
{
- struct sigqueue *q = 0;
+ struct sigqueue *q = NULL;
+ struct user_struct *user;
- if (atomic_read(&nr_queued_signals) < max_queued_signals)
- q = kmem_cache_alloc(sigqueue_cachep, GFP_ATOMIC);
- if (q) {
- atomic_inc(&nr_queued_signals);
+ /*
+ * In order to avoid problems with "switch_user()", we want to make
+ * sure that the compiler doesn't re-load "t->user"
+ */
+ user = t->user;
+ barrier();
+ atomic_inc(&user->sigpending);
+ if (override_rlimit ||
+ atomic_read(&user->sigpending) <=
+ t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
+ q = kmem_cache_alloc(sigqueue_cachep, flags);
+ if (unlikely(q == NULL)) {
+ atomic_dec(&user->sigpending);
+ } else {
INIT_LIST_HEAD(&q->list);
q->flags = 0;
- q->lock = 0;
+ q->user = get_uid(user);
}
return(q);
}
-static inline void __sigqueue_free(struct sigqueue *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);
- atomic_dec(&nr_queued_signals);
}
-static void flush_sigqueue(struct sigpending *queue)
+void flush_sigqueue(struct sigpending *queue)
{
struct sigqueue *q;
/*
* Flush all pending signals for a task.
*/
-
-void
-flush_signals(struct task_struct *t)
+void flush_signals(struct task_struct *t)
{
unsigned long flags;
spin_unlock_irqrestore(&t->sighand->siglock, flags);
}
-/*
- * This function expects the tasklist_lock write-locked.
- */
-void __exit_sighand(struct task_struct *tsk)
-{
- struct sighand_struct * sighand = tsk->sighand;
-
- /* Ok, we're done with the signal handlers */
- tsk->sighand = NULL;
- if (atomic_dec_and_test(&sighand->count))
- kmem_cache_free(sighand_cachep, sighand);
-}
-
-void exit_sighand(struct task_struct *tsk)
-{
- write_lock_irq(&tasklist_lock);
- __exit_sighand(tsk);
- write_unlock_irq(&tasklist_lock);
-}
-
-/*
- * This function expects the tasklist_lock write-locked.
- */
-void __exit_signal(struct task_struct *tsk)
-{
- struct signal_struct * sig = tsk->signal;
- struct sighand_struct * sighand = tsk->sighand;
-
- if (!sig)
- BUG();
- if (!atomic_read(&sig->count))
- BUG();
- spin_lock(&sighand->siglock);
- if (atomic_dec_and_test(&sig->count)) {
- if (tsk == sig->curr_target)
- sig->curr_target = next_thread(tsk);
- tsk->signal = NULL;
- spin_unlock(&sighand->siglock);
- flush_sigqueue(&sig->shared_pending);
- } else {
- /*
- * If there is any task waiting for the group exit
- * then notify it:
- */
- if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) {
- wake_up_process(sig->group_exit_task);
- sig->group_exit_task = NULL;
- }
- if (tsk == sig->curr_target)
- sig->curr_target = next_thread(tsk);
- tsk->signal = NULL;
- spin_unlock(&sighand->siglock);
- sig = NULL; /* Marker for below. */
- }
- clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
- flush_sigqueue(&tsk->pending);
- if (sig) {
- /*
- * We are cleaning up the signal_struct here. We delayed
- * calling exit_itimers until after flush_sigqueue, just in
- * case our thread-local pending queue contained a queued
- * timer signal that would have been cleared in
- * exit_itimers. When that called sigqueue_free, it would
- * attempt to re-take the tasklist_lock and deadlock. This
- * can never happen if we ensure that all queues the
- * timer's signal might be queued on have been flushed
- * first. The shared_pending queue, and our own pending
- * queue are the only queues the timer could be on, since
- * there are no other threads left in the group and timer
- * signals are constrained to threads inside the group.
- */
- exit_itimers(sig);
- kmem_cache_free(signal_cachep, sig);
- }
-}
-
-void exit_signal(struct task_struct *tsk)
-{
- write_lock_irq(&tasklist_lock);
- __exit_signal(tsk);
- write_unlock_irq(&tasklist_lock);
-}
-
/*
* Flush all handlers for a task.
*/
spin_unlock_irqrestore(¤t->sighand->siglock, flags);
}
-static inline int collect_signal(int sig, struct sigpending *list, siginfo_t *info)
+static int collect_signal(int sig, struct sigpending *list, siginfo_t *info)
{
- struct sigqueue *q, *first = 0;
+ struct sigqueue *q, *first = NULL;
int still_pending = 0;
if (unlikely(!sigismember(&list->signal, sig)))
static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
siginfo_t *info)
{
- int sig = 0;
+ int sig = next_signal(pending, mask);
- sig = next_signal(pending, mask);
if (sig) {
if (current->notifier) {
if (sigismember(current->notifier_mask, sig)) {
if (!collect_signal(sig, pending, info))
sig = 0;
-
}
- recalc_sigpending();
return sig;
}
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){
+ /*
+ * 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);
do_schedule_next_timer(info);
+ spin_lock(&tsk->sighand->siglock);
}
return signr;
}
set_tsk_thread_flag(t, TIF_SIGPENDING);
/*
- * If resume is set, we want to wake it up in the TASK_STOPPED case.
- * We don't check for TASK_STOPPED because there is a race with it
+ * 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
* executing another processor and just now entering stopped state.
- * By calling wake_up_process any time resume is set, we ensure
- * the process will wake up and handle its stop or death signal.
+ * 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;
+ mask |= TASK_STOPPED | TASK_TRACED;
if (!wake_up_state(t, mask))
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.
+ *
+ * This version takes a sigset mask and looks at all signals,
+ * not just those in the first mask word.
+ */
+static int rm_from_queue_full(sigset_t *mask, struct sigpending *s)
+{
+ struct sigqueue *q, *n;
+ sigset_t m;
+
+ sigandsets(&m, mask, &s->signal);
+ if (sigisemptyset(&m))
+ return 0;
+
+ signandsets(&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);
+ }
+ }
+ return 1;
+}
/*
* Remove signals in mask from the pending set and queue.
* Returns 1 if any signals were found.
struct task_struct *t)
{
int error = -EINVAL;
- if (sig < 0 || sig > _NSIG)
+
+ if (!valid_signal(sig))
return error;
+
+ if ((info != SEND_SIG_NOINFO) &&
+ (is_si_special(info) || !SI_FROMUSER(info)))
+ goto skip;
+
+ vxdprintk(VXD_CBIT(misc, 7),
+ "check_kill_permission(%d,%p,%p[#%u,%u])",
+ sig, info, t, vx_task_xid(t), t->pid);
+
error = -EPERM;
- if ((!info || ((unsigned long)info != 1 &&
- (unsigned long)info != 2 && SI_FROMUSER(info)))
- && ((sig != SIGCONT) ||
- (current->signal->session != t->signal->session))
+ if (((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 error;
- return security_task_kill(t, info, sig);
+
+ error = -ESRCH;
+ if (!vx_check(vx_task_xid(t), VS_WATCH_P|VS_IDENT)) {
+ vxdprintk(current->xid || VXD_CBIT(misc, 7),
+ "signal %d[%p] xid mismatch %p[#%u,%u] xid=#%u",
+ sig, info, t, vx_task_xid(t), t->pid, current->xid);
+ return error;
+ }
+skip:
+ error = security_task_kill(t, info, sig, 0);
+ if (!error)
+ audit_signal_info(sig, t); /* Let audit system see the signal */
+ return error;
}
-/* forward decl */
-static void do_notify_parent_cldstop(struct task_struct *tsk,
- struct task_struct *parent);
/*
* Handle magic process-wide effects of stop/continue signals.
{
struct task_struct *t;
+ if (p->signal->flags & SIGNAL_GROUP_EXIT)
+ /*
+ * The process is in the middle of dying already.
+ */
+ return;
+
if (sig_kernel_stop(sig)) {
/*
* This is a stop signal. Remove SIGCONT from all queues.
* the SIGCHLD was pending on entry to this kill.
*/
p->signal->group_stop_count = 0;
- if (p->ptrace & PT_PTRACED)
- do_notify_parent_cldstop(p, p->parent);
- else
- do_notify_parent_cldstop(
- p->group_leader,
- p->group_leader->real_parent);
+ 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);
t = p;
t = next_thread(t);
} while (t != p);
+
+ if (p->signal->flags & SIGNAL_STOP_STOPPED) {
+ /*
+ * We were in fact stopped, and are now continued.
+ * Notify the parent with CLD_CONTINUED.
+ */
+ 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);
+ } 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;
+ }
+ } else if (sig == SIGKILL) {
+ /*
+ * Make sure that any pending stop signal already dequeued
+ * is undone by the wakeup for SIGKILL.
+ */
+ p->signal->flags = 0;
}
}
-static int send_signal(int sig, struct siginfo *info, struct sigpending *signals)
+static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
+ struct sigpending *signals)
{
struct sigqueue * q = NULL;
int ret = 0;
* fast-pathed signals for kernel-internal things like SIGSTOP
* or SIGKILL.
*/
- if ((unsigned long)info == 2)
+ if (info == SEND_SIG_FORCED)
goto out_set;
/* Real-time signals must be queued if sent by sigqueue, or
make sure at least one signal gets delivered and don't
pass on the info struct. */
- if (atomic_read(&nr_queued_signals) < max_queued_signals)
- q = kmem_cache_alloc(sigqueue_cachep, GFP_ATOMIC);
-
+ q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
+ (is_si_special(info) ||
+ info->si_code >= 0)));
if (q) {
- atomic_inc(&nr_queued_signals);
- q->flags = 0;
list_add_tail(&q->list, &signals->list);
switch ((unsigned long) info) {
- case 0:
+ 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 1:
+ case (unsigned long) SEND_SIG_PRIV:
q->info.si_signo = sig;
q->info.si_errno = 0;
q->info.si_code = SI_KERNEL;
copy_siginfo(&q->info, info);
break;
}
- } else {
- if (sig >= SIGRTMIN && info && (unsigned long)info != 1
- && info->si_code != SI_USER)
+ } 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().
*/
return -EAGAIN;
- if (((unsigned long)info > 1) && (info->si_code == SI_TIMER))
- /*
- * Set up a return to indicate that we dropped
- * the signal.
- */
- ret = info->si_sys_private;
}
out_set:
#define LEGACY_QUEUE(sigptr, sig) \
(((sig) < SIGRTMIN) && sigismember(&(sigptr)->signal, (sig)))
+int print_fatal_signals = 0;
+
+static void print_fatal_signal(struct pt_regs *regs, int signr)
+{
+ printk("%s/%d: potentially unexpected fatal signal %d.\n",
+ current->comm, current->pid, signr);
+
+#ifdef __i386__
+ printk("code at %08lx: ", regs->eip);
+ {
+ int i;
+ for (i = 0; i < 16; i++) {
+ unsigned char insn;
+
+ __get_user(insn, (unsigned char *)(regs->eip + i));
+ printk("%02x ", insn);
+ }
+ }
+#endif
+ printk("\n");
+ show_regs(regs);
+}
+
+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);
static int
specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
{
int ret = 0;
- if (!irqs_disabled())
- BUG();
-#ifdef CONFIG_SMP
- if (!spin_is_locked(&t->sighand->siglock))
- BUG();
-#endif
-
- if (((unsigned long)info > 2) && (info->si_code == SI_TIMER))
- /*
- * Set up a return to indicate that we dropped the signal.
- */
- ret = info->si_sys_private;
+ BUG_ON(!irqs_disabled());
+ assert_spin_locked(&t->sighand->siglock);
/* Short-circuit ignored signals. */
if (sig_ignored(t, sig))
if (LEGACY_QUEUE(&t->pending, sig))
goto out;
- ret = send_signal(sig, info, &t->pending);
+ ret = send_signal(sig, info, t, &t->pending);
if (!ret && !sigismember(&t->blocked, sig))
signal_wake_up(t, sig == SIGKILL);
out:
/*
* 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.
*/
-
int
force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
{
unsigned long int flags;
- int ret;
+ int ret, blocked, ignored;
+ struct k_sigaction *action;
spin_lock_irqsave(&t->sighand->siglock, flags);
- if (sigismember(&t->blocked, sig) || t->sighand->action[sig-1].sa.sa_handler == SIG_IGN) {
- t->sighand->action[sig-1].sa.sa_handler = SIG_DFL;
- sigdelset(&t->blocked, sig);
- recalc_sigpending_tsk(t);
+ 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_tsk(t);
+ }
}
ret = specific_send_sig_info(sig, info, t);
spin_unlock_irqrestore(&t->sighand->siglock, flags);
void
force_sig_specific(int sig, struct task_struct *t)
{
- unsigned long int flags;
-
- spin_lock_irqsave(&t->sighand->siglock, flags);
- if (t->sighand->action[sig-1].sa.sa_handler == SIG_IGN)
- t->sighand->action[sig-1].sa.sa_handler = SIG_DFL;
- sigdelset(&t->blocked, sig);
- recalc_sigpending_tsk(t);
- specific_send_sig_info(sig, (void *)2, t);
- spin_unlock_irqrestore(&t->sighand->siglock, flags);
+ force_sig_info(sig, SEND_SIG_FORCED, t);
}
/*
* as soon as they're available, so putting the signal on the shared queue
* will be equivalent to sending it to one such thread.
*/
-#define wants_signal(sig, p, mask) \
- (!sigismember(&(p)->blocked, sig) \
- && !((p)->state & mask) \
- && !((p)->flags & PF_EXITING) \
- && (task_curr(p) || !signal_pending(p)))
-
+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, unsigned int mask)
+__group_complete_signal(int sig, struct task_struct *p)
{
struct task_struct *t;
* If the main thread wants the signal, it gets first crack.
* Probably the least surprising to the average bear.
*/
- if (wants_signal(sig, p, mask))
+ if (wants_signal(sig, p))
t = p;
else if (thread_group_empty(p))
/*
if (t == NULL)
/* restart balancing at this thread */
t = p->signal->curr_target = p;
- BUG_ON(t->tgid != p->tgid);
- while (!wants_signal(sig, t, mask)) {
+ while (!wants_signal(sig, t)) {
t = next_thread(t);
if (t == p->signal->curr_target)
/*
* 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->group_exit &&
+ if (sig_fatal(p, sig) && !(p->signal->flags & SIGNAL_GROUP_EXIT) &&
!sigismember(&t->real_blocked, sig) &&
- (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
+ (sig == SIGKILL || !tracehook_consider_fatal_signal(t, sig))) {
/*
* This signal will be fatal to the whole group.
*/
* running and doing things after a slower
* thread has the fatal signal pending.
*/
- p->signal->group_exit = 1;
+ p->signal->flags = SIGNAL_GROUP_EXIT;
p->signal->group_exit_code = sig;
p->signal->group_stop_count = 0;
t = p;
return;
}
-static int
+int
__group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
- unsigned int mask;
int ret = 0;
-#ifdef CONFIG_SMP
- if (!spin_is_locked(&p->sighand->siglock))
- BUG();
-#endif
+ assert_spin_locked(&p->sighand->siglock);
handle_stop_signal(sig, p);
- if (((unsigned long)info > 2) && (info->si_code == SI_TIMER))
- /*
- * Set up a return to indicate that we dropped the signal.
- */
- ret = info->si_sys_private;
-
/* Short-circuit ignored signals. */
if (sig_ignored(p, sig))
return ret;
/* This is a non-RT signal and we already have one queued. */
return ret;
- /*
- * Don't bother zombies and stopped tasks (but
- * SIGKILL will punch through stopped state)
- */
- mask = TASK_DEAD | TASK_ZOMBIE;
- if (sig != SIGKILL)
- mask |= TASK_STOPPED;
-
/*
* 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->signal->shared_pending);
+ ret = send_signal(sig, info, p, &p->signal->shared_pending);
if (unlikely(ret))
return ret;
- __group_complete_signal(sig, p, mask);
+ __group_complete_signal(sig, p);
return 0;
}
{
struct task_struct *t;
+ p->signal->flags = SIGNAL_GROUP_EXIT;
p->signal->group_stop_count = 0;
if (thread_group_empty(p))
/*
* Don't bother with already dead threads
*/
- if (t->state & (TASK_ZOMBIE|TASK_DEAD))
+ if (t->exit_state)
continue;
/*
if (t != p->group_leader)
t->exit_signal = -1;
+ /* SIGKILL will be handled before any pending SIGSTOP */
sigaddset(&t->pending.signal, SIGKILL);
- rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
signal_wake_up(t, 1);
}
}
/*
- * Must be called with the tasklist_lock held for reading!
+ * 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;
+
+ for (;;) {
+ sighand = rcu_dereference(tsk->sighand);
+ if (unlikely(sighand == NULL))
+ break;
+
+ spin_lock_irqsave(&sighand->siglock, *flags);
+ if (likely(sighand == tsk->sighand))
+ break;
+ spin_unlock_irqrestore(&sighand->siglock, *flags);
+ }
+
+ return sighand;
+}
+
int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
unsigned long flags;
int ret;
ret = check_kill_permission(sig, info, p);
- if (!ret && sig && p->sighand) {
- spin_lock_irqsave(&p->sighand->siglock, flags);
- ret = __group_send_sig_info(sig, info, p);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
+
+ if (!ret && sig) {
+ ret = -ESRCH;
+ if (lock_task_sighand(p, &flags)) {
+ ret = __group_send_sig_info(sig, info, p);
+ unlock_task_sighand(p, &flags);
+ }
}
return ret;
}
/*
- * kill_pg_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)
*/
-int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp)
+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);
+ success |= !err;
+ retval = err;
+ } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+ return success ? 0 : retval;
+}
+
+int kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
{
- struct task_struct *p;
- struct list_head *l;
- struct pid *pid;
int retval;
- int found;
+ 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;
- found = 0;
- retval = 0;
- for_each_task_pid(pgrp, PIDTYPE_PGID, p, l, pid) {
- int err;
-
- found = 1;
- err = group_send_sig_info(sig, info, p);
- if (!retval)
- retval = err;
- }
- return found ? retval : -ESRCH;
+ return __kill_pgrp_info(sig, info, find_pid(pgrp));
}
int
return retval;
}
-/*
- * kill_sl_info() sends a signal to the session leader: this is used
- * to send SIGHUP to the controlling process of a terminal when
- * the connection is lost.
- */
-
-
-int
-kill_sl_info(int sig, struct siginfo *info, pid_t sid)
+int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
{
- int err, retval = -EINVAL;
- struct pid *pid;
- struct list_head *l;
+ int error;
+ int acquired_tasklist_lock = 0;
struct task_struct *p;
- if (sid <= 0)
- goto out;
-
- retval = -ESRCH;
- read_lock(&tasklist_lock);
- for_each_task_pid(sid, PIDTYPE_SID, p, l, pid) {
- if (!p->signal->leader)
- continue;
- err = group_send_sig_info(sig, info, p);
- if (retval)
- retval = err;
+ rcu_read_lock();
+ if (unlikely(sig_needs_tasklist(sig))) {
+ read_lock(&tasklist_lock);
+ acquired_tasklist_lock = 1;
}
- read_unlock(&tasklist_lock);
-out:
- return retval;
+ p = pid_task(pid, PIDTYPE_PID);
+ error = -ESRCH;
+ if (p && vx_check(vx_task_xid(p), VS_IDENT))
+ error = group_send_sig_info(sig, info, p);
+ if (unlikely(acquired_tasklist_lock))
+ read_unlock(&tasklist_lock);
+ rcu_read_unlock();
+ return error;
}
-int
-kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+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_pid(vx_rmap_pid(pid)));
+ rcu_read_unlock();
+ return error;
+}
+
+/* like kill_pid_info(), but doesn't use uid/euid of "current" */
+int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
+ uid_t uid, uid_t euid, u32 secid)
+{
+ int ret = -EINVAL;
struct task_struct *p;
+ if (!valid_signal(sig))
+ return ret;
+
read_lock(&tasklist_lock);
- p = find_task_by_pid(pid);
- error = -ESRCH;
- if (p)
- error = group_send_sig_info(sig, info, p);
+ 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)) {
+ 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);
+ }
+out_unlock:
read_unlock(&tasklist_lock);
- return error;
+ return ret;
}
-
+EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
/*
* kill_something_info() interprets pid in interesting ways just like kill(2).
read_lock(&tasklist_lock);
for_each_process(p) {
- if (p->pid > 1 && p->tgid != current->tgid) {
+ if (vx_check(vx_task_xid(p), VS_ADMIN_P|VS_IDENT) &&
+ p->pid > 1 && p->tgid != current->tgid) {
int err = group_send_sig_info(sig, info, p);
++count;
if (err != -EPERM)
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
return ret;
}
+#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, (void*)(long)(priv != 0), p);
+ return send_sig_info(sig, __si_special(priv), p);
}
/*
void
force_sig(int sig, struct task_struct *p)
{
- force_sig_info(sig, (void*)1L, 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..
+ */
int
-kill_pg(pid_t pgrp, int sig, int priv)
+force_sigsegv(int sig, struct task_struct *p)
{
- return kill_pg_info(sig, (void *)(long)(priv != 0), pgrp);
+ 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);
+ return 0;
}
+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
-kill_sl(pid_t sess, int sig, int priv)
+kill_pg(pid_t pgrp, int sig, int priv)
{
- return kill_sl_info(sig, (void *)(long)(priv != 0), sess);
+ return kill_pg_info(sig, __si_special(priv), pgrp);
}
int
kill_proc(pid_t pid, int sig, int priv)
{
- return kill_proc_info(sig, (void *)(long)(priv != 0), pid);
+ return kill_proc_info(sig, __si_special(priv), pid);
}
/*
{
struct sigqueue *q;
- if ((q = __sigqueue_alloc()))
+ if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0)))
q->flags |= SIGQUEUE_PREALLOC;
return(q);
}
* pending queue.
*/
if (unlikely(!list_empty(&q->list))) {
- read_lock(&tasklist_lock);
- spin_lock_irqsave(q->lock, flags);
+ 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(q->lock, flags);
+ spin_unlock_irqrestore(lock, flags);
read_unlock(&tasklist_lock);
}
q->flags &= ~SIGQUEUE_PREALLOC;
__sigqueue_free(q);
}
-int
-send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
+int send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
{
unsigned long flags;
int ret = 0;
+ BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+
/*
- * 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.
+ * 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
*/
- BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
- read_lock(&tasklist_lock);
- spin_lock_irqsave(&p->sighand->siglock, flags);
-
+ 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.
*/
- if (q->info.si_code != SI_TIMER)
- BUG();
+ 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;
}
- q->lock = &p->sighand->siglock;
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:
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
- read_unlock(&tasklist_lock);
- return(ret);
+ unlock_task_sighand(p, &flags);
+out_err:
+ rcu_read_unlock();
+
+ return ret;
}
int
send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
{
unsigned long flags;
- unsigned int mask;
int ret = 0;
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);
* the overrun count. Other uses should not try to
* send the signal multiple times.
*/
- if (q->info.si_code != SI_TIMER)
- BUG();
+ BUG_ON(q->info.si_code != SI_TIMER);
q->info.si_overrun++;
goto out;
}
- /*
- * Don't bother zombies and stopped tasks (but
- * SIGKILL will punch through stopped state)
- */
- mask = TASK_DEAD | TASK_ZOMBIE;
- if (sig != SIGKILL)
- mask |= TASK_STOPPED;
/*
* Put this signal on the shared-pending queue.
* We always use the shared queue for process-wide signals,
* to avoid several races.
*/
- q->lock = &p->sighand->siglock;
list_add_tail(&q->list, &p->signal->shared_pending.list);
sigaddset(&p->signal->shared_pending.signal, sig);
- __group_complete_signal(sig, p, mask);
+ __group_complete_signal(sig, p);
out:
spin_unlock_irqrestore(&p->sighand->siglock, flags);
read_unlock(&tasklist_lock);
- return(ret);
+ return ret;
}
/*
- * Joy. Or not. Pthread wants us to wake up every thread
- * in our parent group.
+ * Wake up any threads in the parent blocked in wait* syscalls.
*/
-static void __wake_up_parent(struct task_struct *p,
+static inline void __wake_up_parent(struct task_struct *p,
struct task_struct *parent)
{
- struct task_struct *tsk = parent;
-
- /*
- * Fortunately this is not necessary for thread groups:
- */
- if (p->tgid == tsk->tgid) {
- wake_up_interruptible(&tsk->wait_chldexit);
- return;
- }
-
- do {
- wake_up_interruptible(&tsk->wait_chldexit);
- tsk = next_thread(tsk);
- if (tsk->signal != parent->signal)
- BUG();
- } while (tsk != parent);
+ wake_up_interruptible_sync(&parent->signal->wait_chldexit);
}
/*
- * Let a parent know about a status change of a child.
+ * Let a parent know about the death of a child.
+ * For a stopped/continued status change, use do_notify_parent_cldstop instead.
*/
void do_notify_parent(struct task_struct *tsk, int sig)
{
struct siginfo info;
unsigned long flags;
- int why, status;
struct sighand_struct *psig;
- if (sig == -1)
- BUG();
+ BUG_ON(sig == -1);
+
+ /* do_notify_parent_cldstop should have been called instead. */
+ BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED));
- BUG_ON(tsk->group_leader != tsk && tsk->group_leader->state != TASK_ZOMBIE && !tsk->ptrace);
- BUG_ON(tsk->group_leader == tsk && !thread_group_empty(tsk) && !tsk->ptrace);
+ BUG_ON(tsk->group_leader != tsk || !thread_group_empty(tsk));
info.si_signo = sig;
info.si_errno = 0;
info.si_uid = tsk->uid;
/* FIXME: find out whether or not this is supposed to be c*time. */
- info.si_utime = tsk->utime;
- info.si_stime = tsk->stime;
-
- status = tsk->exit_code & 0x7f;
- why = SI_KERNEL; /* shouldn't happen */
- switch (tsk->state) {
- case TASK_STOPPED:
- /* FIXME -- can we deduce CLD_TRAPPED or CLD_CONTINUED? */
- if (tsk->ptrace & PT_PTRACED)
- why = CLD_TRAPPED;
- else
- why = CLD_STOPPED;
- break;
+ 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));
- default:
- if (tsk->exit_code & 0x80)
- why = CLD_DUMPED;
- else if (tsk->exit_code & 0x7f)
- why = CLD_KILLED;
- else {
- why = CLD_EXITED;
- status = tsk->exit_code >> 8;
- }
- break;
+ 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;
}
- info.si_code = why;
- info.si_status = status;
psig = tsk->parent->sighand;
spin_lock_irqsave(&psig->siglock, flags);
- if (sig == SIGCHLD && tsk->state != TASK_STOPPED &&
+ if (sig == SIGCHLD &&
(psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
(psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
/*
if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
sig = 0;
}
- if (sig > 0 && sig <= _NSIG)
+ 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);
}
-
-/*
- * We need the tasklist lock because it's the only
- * thing that protects out "parent" pointer.
- *
- * exit.c calls "do_notify_parent()" directly, because
- * it already has the tasklist lock.
- */
-void
-notify_parent(struct task_struct *tsk, int sig)
-{
- if (sig != -1) {
- read_lock(&tasklist_lock);
- do_notify_parent(tsk, sig);
- read_unlock(&tasklist_lock);
- }
-}
-
-static void
-do_notify_parent_cldstop(struct task_struct *tsk, struct task_struct *parent)
+void do_notify_parent_cldstop(struct task_struct *tsk, int why)
{
struct siginfo info;
unsigned long flags;
+ struct task_struct *parent;
struct sighand_struct *sighand;
info.si_signo = SIGCHLD;
info.si_uid = tsk->uid;
/* FIXME: find out whether or not this is supposed to be c*time. */
- info.si_utime = tsk->utime;
- info.si_stime = tsk->stime;
+ info.si_utime = cputime_to_jiffies(tsk->utime);
+ info.si_stime = cputime_to_jiffies(tsk->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();
+ }
- info.si_status = tsk->exit_code & 0x7f;
- info.si_code = CLD_STOPPED;
+ /*
+ * Tracing can decide that we should not do the normal notification.
+ */
+ if (tracehook_notify_cldstop(tsk, &info))
+ return;
+
+ tsk = tsk->group_leader;
+ parent = tsk->parent;
sighand = parent->sighand;
spin_lock_irqsave(&sighand->siglock, flags);
spin_unlock_irqrestore(&sighand->siglock, flags);
}
-
-#ifndef HAVE_ARCH_GET_SIGNAL_TO_DELIVER
-
static void
finish_stop(int stop_count)
{
* 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)) {
+ if (!tracehook_finish_stop(stop_count <= 0) && stop_count <= 0) {
read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current, current->parent);
- read_unlock(&tasklist_lock);
- }
- else if (stop_count == 0) {
- read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current->group_leader,
- current->group_leader->real_parent);
+ do_notify_parent_cldstop(current, CLD_STOPPED);
read_unlock(&tasklist_lock);
}
- schedule();
+ do {
+ schedule();
+ } while (try_to_freeze());
/*
* Now we don't run again until continued.
*/
/*
* This performs the stopping for SIGSTOP and other stop signals.
* We have to stop all threads in the thread group.
+ * Returns nonzero if we've actually stopped and released the siglock.
+ * Returns zero if we didn't stop and still hold the siglock.
*/
-static void
-do_signal_stop(int signr)
+static int do_signal_stop(int signr)
{
struct signal_struct *sig = current->signal;
- struct sighand_struct *sighand = current->sighand;
- int stop_count = -1;
+ int stop_count;
- /* spin_lock_irq(&sighand->siglock) is now done in caller */
+ if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED))
+ return 0;
if (sig->group_stop_count > 0) {
/*
* There is a group stop in progress. We don't need to
* start another one.
*/
- signr = sig->group_exit_code;
stop_count = --sig->group_stop_count;
- current->exit_code = signr;
- set_current_state(TASK_STOPPED);
- spin_unlock_irq(&sighand->siglock);
- }
- else if (thread_group_empty(current)) {
- /*
- * Lock must be held through transition to stopped state.
- */
- current->exit_code = signr;
- set_current_state(TASK_STOPPED);
- spin_unlock_irq(&sighand->siglock);
- }
- else {
+ } else {
/*
* There is no group stop already in progress.
- * We must initiate one now, but that requires
- * dropping siglock to get both the tasklist lock
- * and siglock again in the proper order. Note that
- * this allows an intervening SIGCONT to be posted.
- * We need to check for that and bail out if necessary.
+ * We must initiate one now.
*/
struct task_struct *t;
- spin_unlock_irq(&sighand->siglock);
-
- /* signals can be posted during this window */
-
- read_lock(&tasklist_lock);
- spin_lock_irq(&sighand->siglock);
+ sig->group_exit_code = signr;
- if (unlikely(sig->group_exit)) {
+ stop_count = 0;
+ for (t = next_thread(current); t != current; t = next_thread(t))
/*
- * There is a group exit in progress now.
- * We'll just ignore the stop and process the
- * associated fatal signal.
+ * Setting state to TASK_STOPPED for a group
+ * stop is always done with the siglock held,
+ * so this check has no races.
*/
- spin_unlock_irq(&sighand->siglock);
- read_unlock(&tasklist_lock);
- return;
- }
-
- if (unlikely(sig_avoid_stop_race())) {
- /*
- * Either a SIGCONT or a SIGKILL signal was
- * posted in the siglock-not-held window.
- */
- spin_unlock_irq(&sighand->siglock);
- read_unlock(&tasklist_lock);
- return;
- }
-
- if (sig->group_stop_count == 0) {
- sig->group_exit_code = signr;
- stop_count = 0;
- 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->state < TASK_STOPPED) {
- stop_count++;
- signal_wake_up(t, 0);
- }
- sig->group_stop_count = stop_count;
- }
- else {
- /* A race with another thread while unlocked. */
- signr = sig->group_exit_code;
- stop_count = --sig->group_stop_count;
- }
-
- current->exit_code = signr;
- set_current_state(TASK_STOPPED);
-
- spin_unlock_irq(&sighand->siglock);
- read_unlock(&tasklist_lock);
+ if (!t->exit_state &&
+ !(t->state & (TASK_STOPPED|TASK_TRACED))) {
+ stop_count++;
+ signal_wake_up(t, 0);
+ }
+ sig->group_stop_count = stop_count;
}
+ if (stop_count == 0)
+ sig->flags = SIGNAL_STOP_STOPPED;
+ current->exit_code = sig->group_exit_code;
+ __set_current_state(TASK_STOPPED);
+
+ spin_unlock_irq(¤t->sighand->siglock);
finish_stop(stop_count);
+ return 1;
}
/*
* We return zero if we still hold the siglock and should look
* for another signal without checking group_stop_count again.
*/
-static inline int handle_group_stop(void)
+static int handle_group_stop(void)
{
int stop_count;
return 0;
}
- if (current->signal->group_exit)
+ 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.
* 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);
return 1;
}
-int get_signal_to_deliver(siginfo_t *info, struct pt_regs *regs, void *cookie)
+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;
+ try_to_freeze();
+
relock:
spin_lock_irq(¤t->sighand->siglock);
for (;;) {
handle_group_stop())
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);
-
- /*
- * If there is a group stop in progress,
- * we must participate in the bookkeeping.
- */
- if (current->signal->group_stop_count > 0)
- --current->signal->group_stop_count;
-
- /* Let the debugger run. */
- current->exit_code = signr;
- current->last_siginfo = info;
- set_current_state(TASK_STOPPED);
- spin_unlock_irq(¤t->sighand->siglock);
- notify_parent(current, SIGCHLD);
- schedule();
-
- current->last_siginfo = NULL;
-
- /* We're back. Did the debugger cancel the sig? */
- spin_lock_irq(¤t->sighand->siglock);
- signr = current->exit_code;
- if (signr == 0)
- continue;
-
- 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 = current->parent->pid;
- info->si_uid = current->parent->uid;
- }
+ /*
+ * 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 {
+ signr = dequeue_signal(current, mask, info);
- /* If the (new) signal is now blocked, requeue it. */
- if (sigismember(¤t->blocked, signr)) {
- specific_send_sig_info(signr, info, current);
- continue;
- }
+ if (!signr)
+ break; /* will return 0 */
+ ka = ¤t->sighand->action[signr-1];
}
- ka = ¤t->sighand->action[signr-1];
if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
continue;
- if (ka->sa.sa_handler != SIG_DFL) /* Run the handler. */
+ if (ka->sa.sa_handler != SIG_DFL) {
+ /* Run the handler. */
+ *return_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;
- /* Init gets no signals it doesn't want. */
- if (current->pid == 1)
+ /*
+ * 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.
+ */
+ if (current == child_reaper(current))
+ continue;
+
+ /* virtual init is protected against user signals */
+ if ((info->si_code == SI_USER) &&
+ vx_current_initpid(current->pid))
continue;
if (sig_kernel_stop(signr)) {
* This allows an intervening SIGCONT to be posted.
* We need to check for that and bail out if necessary.
*/
- if (signr == SIGSTOP) {
- do_signal_stop(signr); /* releases siglock */
- goto relock;
- }
- spin_unlock_irq(¤t->sighand->siglock);
+ if (signr != SIGSTOP) {
+ spin_unlock_irq(¤t->sighand->siglock);
- /* signals can be posted during this window */
+ /* signals can be posted during this window */
- if (is_orphaned_pgrp(process_group(current)))
- goto relock;
+ if (is_orphaned_pgrp(process_group(current)))
+ goto relock;
- spin_lock_irq(¤t->sighand->siglock);
- if (unlikely(sig_avoid_stop_race())) {
- /*
- * Either a SIGCONT or a SIGKILL signal was
- * posted in the siglock-not-held window.
- */
- continue;
+ spin_lock_irq(¤t->sighand->siglock);
}
- do_signal_stop(signr); /* releases siglock */
- goto relock;
+ if (likely(do_signal_stop(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(¤t->sighand->siglock);
* Anything else is fatal, maybe with a core dump.
*/
current->flags |= PF_SIGNALED;
- if (sig_kernel_coredump(signr) &&
- do_coredump((long)signr, signr, regs)) {
+ if (print_fatal_signals)
+ print_fatal_signal(regs, signr);
+ if (sig_kernel_coredump(signr)) {
/*
- * That killed all other threads in the group and
- * synchronized with their demise, so there can't
- * be any more left to kill now. The group_exit
- * flags are set by do_coredump. Note that
- * thread_group_empty won't always be true yet,
- * because those threads were blocked in __exit_mm
- * and we just let them go to finish dying.
+ * 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.
*/
- const int code = signr | 0x80;
- BUG_ON(!current->signal->group_exit);
- BUG_ON(current->signal->group_exit_code != code);
- do_exit(code);
- /* NOTREACHED */
+ 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);
return signr;
}
-#endif
-
EXPORT_SYMBOL(recalc_sigpending);
EXPORT_SYMBOL_GPL(dequeue_signal);
EXPORT_SYMBOL(flush_signals);
EXPORT_SYMBOL(force_sig);
-EXPORT_SYMBOL(force_sig_info);
EXPORT_SYMBOL(kill_pg);
-EXPORT_SYMBOL(kill_pg_info);
EXPORT_SYMBOL(kill_proc);
-EXPORT_SYMBOL(kill_proc_info);
-EXPORT_SYMBOL(kill_sl);
-EXPORT_SYMBOL(kill_sl_info);
-EXPORT_SYMBOL(notify_parent);
EXPORT_SYMBOL(send_sig);
EXPORT_SYMBOL(send_sig_info);
-EXPORT_SYMBOL(send_group_sig_info);
-EXPORT_SYMBOL(sigqueue_alloc);
-EXPORT_SYMBOL(sigqueue_free);
-EXPORT_SYMBOL(send_sigqueue);
-EXPORT_SYMBOL(send_group_sigqueue);
EXPORT_SYMBOL(sigprocmask);
EXPORT_SYMBOL(block_all_signals);
EXPORT_SYMBOL(unblock_all_signals);
int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
{
int error;
- sigset_t old_block;
spin_lock_irq(¤t->sighand->siglock);
- old_block = current->blocked;
+ if (oldset)
+ *oldset = current->blocked;
+
error = 0;
switch (how) {
case SIG_BLOCK:
}
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
- if (oldset)
- *oldset = old_block;
+
return error;
}
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
- current->state = TASK_INTERRUPTIBLE;
- timeout = schedule_timeout(timeout);
+ timeout = schedule_timeout_interruptible(timeout);
spin_lock_irq(¤t->sighand->siglock);
sig = dequeue_signal(current, &these, &info);
return kill_something_info(sig, &info, pid);
}
-/**
- * sys_tkill - 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.
- */
-asmlinkage long sys_tgkill(int tgid, int pid, int sig)
+static int do_tkill(int tgid, int pid, int sig)
{
- struct siginfo info;
int error;
+ struct siginfo info;
struct task_struct *p;
- /* This is only valid for single tasks */
- if (pid <= 0 || tgid <= 0)
- return -EINVAL;
-
+ error = -ESRCH;
info.si_signo = sig;
info.si_errno = 0;
info.si_code = SI_TKILL;
read_lock(&tasklist_lock);
p = find_task_by_pid(pid);
- error = -ESRCH;
- if (p && (p->tgid == tgid)) {
+ if (p && (tgid <= 0 || p->tgid == tgid)) {
error = check_kill_permission(sig, &info, p);
/*
* The null signal is a permissions and process existence
}
}
read_unlock(&tasklist_lock);
+
return error;
}
+/**
+ * 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.
+ */
+asmlinkage long sys_tgkill(int tgid, int pid, int sig)
+{
+ /* This is only valid for single tasks */
+ if (pid <= 0 || tgid <= 0)
+ return -EINVAL;
+
+ return do_tkill(tgid, pid, sig);
+}
+
/*
* Send a signal to only one task, even if it's a CLONE_THREAD task.
*/
asmlinkage long
sys_tkill(int pid, int sig)
{
- struct siginfo info;
- int error;
- struct task_struct *p;
-
/* This is only valid for single tasks */
if (pid <= 0)
return -EINVAL;
- 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);
- error = -ESRCH;
- if (p) {
- 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);
- }
- }
- read_unlock(&tasklist_lock);
- return error;
+ return do_tkill(0, pid, sig);
}
asmlinkage long
return kill_proc_info(sig, &info, pid);
}
-int
-do_sigaction(int sig, const struct k_sigaction *act, struct k_sigaction *oact)
+int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
{
struct k_sigaction *k;
+ sigset_t mask;
- if (sig < 1 || sig > _NSIG || (act && sig_kernel_only(sig)))
+ if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
return -EINVAL;
k = ¤t->sighand->action[sig-1];
*oact = *k;
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
* 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))) {
- /*
- * This is a fairly rare case, so we only take the
- * tasklist_lock once we're sure we'll need it.
- * Now we must do this little unlock and relock
- * dance to maintain the lock hierarchy.
- */
+ (act->sa.sa_handler == SIG_DFL && sig_kernel_ignore(sig))) {
struct task_struct *t = current;
- spin_unlock_irq(&t->sighand->siglock);
- read_lock(&tasklist_lock);
- spin_lock_irq(&t->sighand->siglock);
- *k = *act;
- sigdelsetmask(&k->sa.sa_mask,
- sigmask(SIGKILL) | sigmask(SIGSTOP));
- rm_from_queue(sigmask(sig), &t->signal->shared_pending);
+ sigemptyset(&mask);
+ sigaddset(&mask, sig);
+ rm_from_queue_full(&mask, &t->signal->shared_pending);
do {
- rm_from_queue(sigmask(sig), &t->pending);
+ rm_from_queue_full(&mask, &t->pending);
recalc_sigpending_tsk(t);
t = next_thread(t);
} while (t != current);
- spin_unlock_irq(¤t->sighand->siglock);
- read_unlock(&tasklist_lock);
- return 0;
}
-
- *k = *act;
- sigdelsetmask(&k->sa.sa_mask,
- sigmask(SIGKILL) | sigmask(SIGSTOP));
}
spin_unlock_irq(¤t->sighand->siglock);
int error;
if (uoss) {
- oss.ss_sp = (void *) current->sas_ss_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 *ss_sp;
+ void __user *ss_sp;
size_t ss_size;
int ss_flags;
error = -EFAULT;
- if (verify_area(VERIFY_READ, uss, sizeof(*uss))
+ 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))
return error;
}
+#ifdef __ARCH_WANT_SYS_SIGPENDING
+
asmlinkage long
sys_sigpending(old_sigset_t __user *set)
{
return do_sigpending(set, sizeof(*set));
}
-#if !defined(__alpha__)
-/* Alpha has its own versions with special arguments. */
+#endif
+
+#ifdef __ARCH_WANT_SYS_SIGPROCMASK
+/* 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)
out:
return error;
}
+#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
-#ifndef __sparc__
+#ifdef __ARCH_WANT_SYS_RT_SIGACTION
asmlinkage long
sys_rt_sigaction(int sig,
const struct sigaction __user *act,
out:
return ret;
}
-#endif /* __sparc__ */
-#endif
+#endif /* __ARCH_WANT_SYS_RT_SIGACTION */
+
+#ifdef __ARCH_WANT_SYS_SGETMASK
-#if !defined(__alpha__) && !defined(__ia64__) && \
- !defined(__arm__) && !defined(__s390__)
/*
* For backwards compatibility. Functionality superseded by sigprocmask.
*/
return old;
}
-#endif /* !defined(__alpha__) */
+#endif /* __ARCH_WANT_SGETMASK */
-#if !defined(__alpha__) && !defined(__ia64__) && !defined(__mips__) && \
- !defined(__arm__)
+#ifdef __ARCH_WANT_SYS_SIGNAL
/*
* For backwards compatibility. Functionality superseded by sigaction.
*/
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 /* !alpha && !__ia64__ && !defined(__mips__) && !defined(__arm__) */
+#endif /* __ARCH_WANT_SYS_SIGNAL */
-#ifndef HAVE_ARCH_SYS_PAUSE
+#ifdef __ARCH_WANT_SYS_PAUSE
asmlinkage long
sys_pause(void)
return -ERESTARTNOHAND;
}
-#endif /* HAVE_ARCH_SYS_PAUSE */
+#endif
+
+#ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
+asmlinkage long sys_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;
+ sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+ spin_lock_irq(¤t->sighand->siglock);
+ current->saved_sigmask = current->blocked;
+ current->blocked = newset;
+ recalc_sigpending();
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ current->state = TASK_INTERRUPTIBLE;
+ schedule();
+ set_thread_flag(TIF_RESTORE_SIGMASK);
+ return -ERESTARTNOHAND;
+}
+#endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */
+
+__attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma)
+{
+ return NULL;
+}
void __init signals_init(void)
{
kmem_cache_create("sigqueue",
sizeof(struct sigqueue),
__alignof__(struct sigqueue),
- 0, NULL, NULL);
- if (!sigqueue_cachep)
- panic("signals_init(): cannot create sigqueue SLAB cache");
+ SLAB_PANIC, NULL, NULL);
}
git://git.onelab.eu / linux-2.6.git / blobdiff