#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/ptrace.h>
+#include <linux/posix-timers.h>
+#include <linux/signal.h>
+#include <linux/audit.h>
#include <asm/param.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/siginfo.h>
-extern void k_getrusage(struct task_struct *, int, struct rusage *);
-
/*
* SLAB caches for signal bits.
*/
(!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 __user * handler;
return sig;
}
-static struct sigqueue *__sigqueue_alloc(struct task_struct *t, int flags)
+static struct sigqueue *__sigqueue_alloc(struct task_struct *t, unsigned int __nocast flags,
+ int override_rlimit)
{
struct sigqueue *q = NULL;
- if (atomic_read(&t->user->sigpending) <
+ atomic_inc(&t->user->sigpending);
+ if (override_rlimit ||
+ atomic_read(&t->user->sigpending) <=
t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
q = kmem_cache_alloc(sigqueue_cachep, flags);
- if (q) {
+ if (unlikely(q == NULL)) {
+ atomic_dec(&t->user->sigpending);
+ } else {
INIT_LIST_HEAD(&q->list);
q->flags = 0;
q->lock = NULL;
q->user = get_uid(t->user);
- atomic_inc(&q->user->sigpending);
}
return(q);
}
if (!atomic_read(&sig->count))
BUG();
spin_lock(&sighand->siglock);
+ posix_cpu_timers_exit(tsk);
if (atomic_dec_and_test(&sig->count)) {
+ posix_cpu_timers_exit_group(tsk);
if (tsk == sig->curr_target)
sig->curr_target = next_thread(tsk);
tsk->signal = NULL;
* We won't ever get here for the group leader, since it
* will have been the last reference on the signal_struct.
*/
- sig->utime += tsk->utime;
- sig->stime += tsk->stime;
+ sig->utime = cputime_add(sig->utime, tsk->utime);
+ sig->stime = cputime_add(sig->stime, tsk->stime);
sig->min_flt += tsk->min_flt;
sig->maj_flt += tsk->maj_flt;
sig->nvcsw += tsk->nvcsw;
sig->nivcsw += tsk->nivcsw;
+ sig->sched_time += tsk->sched_time;
spin_unlock(&sighand->siglock);
sig = NULL; /* Marker for below. */
}
* signals are constrained to threads inside the group.
*/
exit_itimers(sig);
+ exit_thread_group_keys(sig);
kmem_cache_free(signal_cachep, sig);
}
}
{
int sig = 0;
- sig = next_signal(pending, mask);
+ /* SIGKILL must have priority, otherwise it is quite easy
+ * to create an unkillable process, sending sig < SIGKILL
+ * to self */
+ if (unlikely(sigismember(&pending->signal, SIGKILL))) {
+ if (!sigismember(mask, SIGKILL))
+ sig = SIGKILL;
+ }
+
+ if (likely(!sig))
+ sig = next_signal(pending, mask);
if (sig) {
if (current->notifier) {
if (sigismember(current->notifier_mask, sig)) {
if (!signr)
signr = __dequeue_signal(&tsk->signal->shared_pending,
mask, info);
+ 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.
+ */
+ 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);
}
int error = -EINVAL;
int user;
- if (sig < 0 || sig > _NSIG)
+ if (!valid_signal(sig))
return error;
- user = (!info ||
- (info != SEND_SIG_PRIV &&
- info != SEND_SIG_FORCED &&
- SI_FROMUSER(info)));
+
+ user = (!info || ((unsigned long)info != 1 &&
+ (unsigned long)info != 2 && SI_FROMUSER(info)));
error = -EPERM;
- if (user && (sig != SIGCONT ||
- current->signal->session != t->signal->session)
+ if (user && ((sig != SIGCONT) ||
+ (current->signal->session != t->signal->session))
&& (current->euid ^ t->suid) && (current->euid ^ t->uid)
&& (current->uid ^ t->suid) && (current->uid ^ t->uid)
&& !capable(CAP_KILL))
if (user && !vx_check(vx_task_xid(t), VX_ADMIN|VX_IDENT))
return error;
- return security_task_kill(t, info, sig);
+ error = security_task_kill(t, info, sig);
+ if (!error)
+ audit_signal_info(sig, t); /* Let audit system see the signal */
+ return error;
}
/* forward decl */
{
struct task_struct *t;
+ if (p->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;
- p->signal->stop_state = 1;
+ p->signal->flags = SIGNAL_STOP_CONTINUED;
spin_unlock(&p->sighand->siglock);
if (p->ptrace & PT_PTRACED)
do_notify_parent_cldstop(p, p->parent,
t = next_thread(t);
} while (t != p);
- if (p->signal->stop_state > 0) {
+ if (p->signal->flags & SIGNAL_STOP_STOPPED) {
/*
* We were in fact stopped, and are now continued.
* Notify the parent with CLD_CONTINUED.
*/
- p->signal->stop_state = -1;
+ p->signal->flags = SIGNAL_STOP_CONTINUED;
p->signal->group_exit_code = 0;
spin_unlock(&p->sighand->siglock);
if (p->ptrace & PT_PTRACED)
p->group_leader->real_parent,
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;
}
}
make sure at least one signal gets delivered and don't
pass on the info struct. */
- q = __sigqueue_alloc(t, GFP_ATOMIC);
+ q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
+ ((unsigned long) info < 2 ||
+ info->si_code >= 0)));
if (q) {
list_add_tail(&q->list, &signals->list);
switch ((unsigned long) info) {
if (!irqs_disabled())
BUG();
-#ifdef CONFIG_SMP
- if (!spin_is_locked(&t->sighand->siglock))
- BUG();
-#endif
+ assert_spin_locked(&t->sighand->siglock);
if (((unsigned long)info > 2) && (info->si_code == SI_TIMER))
/*
struct task_struct *t;
/*
- * Don't bother zombies and stopped tasks (but
- * SIGKILL will punch through stopped state)
+ * Don't bother traced and stopped tasks (but
+ * SIGKILL will punch through that).
*/
- mask = EXIT_DEAD | EXIT_ZOMBIE | TASK_TRACED;
- if (sig != SIGKILL)
- mask |= TASK_STOPPED;
+ mask = TASK_STOPPED | TASK_TRACED;
+ if (sig == SIGKILL)
+ mask = 0;
/*
* Now find a thread we can wake up to take the signal off the queue.
* 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))) {
/*
* 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)
{
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))
{
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->exit_state & (EXIT_ZOMBIE|EXIT_DEAD))
+ if (t->exit_state)
continue;
/*
return error;
}
+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);
/*
* kill_something_info() interprets pid in interesting ways just like kill(2).
* Make sure legacy kernel users don't send in bad values
* (normal paths check this in check_kill_permission).
*/
- if (sig < 0 || sig > _NSIG)
+ if (!valid_signal(sig))
return -EINVAL;
/*
{
struct sigqueue *q;
- if ((q = __sigqueue_alloc(current, GFP_KERNEL)))
+ if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0)))
q->flags |= SIGQUEUE_PREALLOC;
return(q);
}
}
/*
- * 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_sync(&tsk->wait_chldexit);
- return;
- }
-
- do {
- wake_up_interruptible_sync(&tsk->wait_chldexit);
- tsk = next_thread(tsk);
- if (tsk->signal != parent->signal)
- BUG();
- } while (tsk != parent);
+ wake_up_interruptible_sync(&parent->signal->wait_chldexit);
}
/*
unsigned long flags;
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));
info.si_uid = tsk->uid;
/* FIXME: find out whether or not this is supposed to be c*time. */
- info.si_utime = tsk->utime + tsk->signal->utime;
- info.si_stime = tsk->stime + tsk->signal->stime;
+ 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_status = tsk->exit_code & 0x7f;
if (tsk->exit_code & 0x80)
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);
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) {
* We always set current->last_siginfo while stopped here.
* That makes it a way to test a stopped process for
* being ptrace-stopped vs being job-control-stopped.
+ *
+ * If we actually decide not to stop at all because the tracer is gone,
+ * we leave nostop_code in current->exit_code.
*/
-static void ptrace_stop(int exit_code, siginfo_t *info)
+static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info)
{
- BUG_ON(!(current->ptrace & PT_PTRACED));
-
/*
* If there is a group stop in progress,
* we must participate in the bookkeeping.
set_current_state(TASK_TRACED);
spin_unlock_irq(¤t->sighand->siglock);
read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current, current->parent, CLD_TRAPPED);
- read_unlock(&tasklist_lock);
- schedule();
+ if (likely(current->ptrace & PT_PTRACED) &&
+ likely(current->parent != current->real_parent ||
+ !(current->ptrace & PT_ATTACHED)) &&
+ (likely(current->parent->signal != current->signal) ||
+ !unlikely(current->signal->flags & SIGNAL_GROUP_EXIT))) {
+ do_notify_parent_cldstop(current, current->parent,
+ CLD_TRAPPED);
+ read_unlock(&tasklist_lock);
+ schedule();
+ } else {
+ /*
+ * By the time we got the lock, our tracer went away.
+ * Don't stop here.
+ */
+ read_unlock(&tasklist_lock);
+ set_current_state(TASK_RUNNING);
+ current->exit_code = nostop_code;
+ }
/*
* We are back. Now reacquire the siglock before touching
/* Let the debugger run. */
spin_lock_irq(¤t->sighand->siglock);
- ptrace_stop(exit_code, &info);
+ ptrace_stop(exit_code, 0, &info);
spin_unlock_irq(¤t->sighand->siglock);
}
-int print_fatal_signals = 0;
-
-static void print_fatal_signal(struct pt_regs *regs, int signr)
-{
- int i;
- unsigned char insn;
- printk("%s/%d: potentially unexpected fatal signal %d.\n",
- current->comm, current->pid, signr);
-
-#ifdef __i386__
- printk("code at %08lx: ", regs->eip);
- for (i = 0; i < 16; i++) {
- __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);
-
-#ifndef HAVE_ARCH_GET_SIGNAL_TO_DELIVER
-
static void
finish_stop(int stop_count)
{
/*
* 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
+static int
do_signal_stop(int signr)
{
struct signal_struct *sig = current->signal;
struct sighand_struct *sighand = current->sighand;
int stop_count = -1;
- /* 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) {
/*
current->exit_code = signr;
set_current_state(TASK_STOPPED);
if (stop_count == 0)
- sig->stop_state = 1;
+ sig->flags = SIGNAL_STOP_STOPPED;
spin_unlock_irq(&sighand->siglock);
}
else if (thread_group_empty(current)) {
*/
current->exit_code = current->signal->group_exit_code = signr;
set_current_state(TASK_STOPPED);
- sig->stop_state = 1;
+ sig->flags = SIGNAL_STOP_STOPPED;
spin_unlock_irq(&sighand->siglock);
}
else {
read_lock(&tasklist_lock);
spin_lock_irq(&sighand->siglock);
- if (unlikely(sig->group_exit)) {
- /*
- * There is a group exit in progress now.
- * We'll just ignore the stop and process the
- * associated fatal signal.
- */
- spin_unlock_irq(&sighand->siglock);
- read_unlock(&tasklist_lock);
- return;
- }
-
- if (unlikely(sig_avoid_stop_race())) {
+ if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED)) {
/*
- * Either a SIGCONT or a SIGKILL signal was
- * posted in the siglock-not-held window.
+ * Another stop or continue happened while we
+ * didn't have the lock. We can just swallow this
+ * signal now. If we raced with a SIGCONT, that
+ * should have just cleared it now. If we raced
+ * with another processor delivering a stop signal,
+ * then the SIGCONT that wakes us up should clear it.
*/
- spin_unlock_irq(&sighand->siglock);
read_unlock(&tasklist_lock);
- return;
+ return 0;
}
if (sig->group_stop_count == 0) {
current->exit_code = signr;
set_current_state(TASK_STOPPED);
if (stop_count == 0)
- sig->stop_state = 1;
+ sig->flags = SIGNAL_STOP_STOPPED;
spin_unlock_irq(&sighand->siglock);
read_unlock(&tasklist_lock);
}
finish_stop(stop_count);
+ return 1;
}
/*
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.
*/
stop_count = --current->signal->group_stop_count;
if (stop_count == 0)
- current->signal->stop_state = 1;
+ 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);
print_fatal_signal(regs, signr);
spin_lock_irq(¤t->sighand->siglock);
}
-
if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
ptrace_signal_deliver(regs, cookie);
/* Let the debugger run. */
- ptrace_stop(signr, info);
+ ptrace_stop(signr, signr, info);
/* We're back. Did the debugger cancel the sig? */
signr = current->exit_code;
if (current->pid == 1)
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)) {
/*
* The default action is to stop all threads in
* 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(signr))) {
+ /* 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);
return signr;
}
-#endif
-
EXPORT_SYMBOL(recalc_sigpending);
EXPORT_SYMBOL_GPL(dequeue_signal);
EXPORT_SYMBOL(flush_signals);
EXPORT_SYMBOL(block_all_signals);
EXPORT_SYMBOL(unblock_all_signals);
+
/*
* System call entry points.
*/
current->state = TASK_INTERRUPTIBLE;
timeout = schedule_timeout(timeout);
+ if (current->flags & PF_FREEZE)
+ refrigerator(PF_FREEZE);
spin_lock_irq(¤t->sighand->siglock);
sig = dequeue_signal(current, &these, &info);
current->blocked = current->real_blocked;
{
struct k_sigaction *k;
- 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];
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))
git://git.onelab.eu / linux-2.6.git / blobdiff