diff options
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 173 |
1 files changed, 93 insertions, 80 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index d282fea8113..f2b96b08fb4 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -262,7 +262,7 @@ next_signal(struct sigpending *pending, sigset_t *mask) return sig; } -static struct sigqueue *__sigqueue_alloc(struct task_struct *t, unsigned int __nocast flags, +static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, int override_rlimit) { struct sigqueue *q = NULL; @@ -397,20 +397,8 @@ void __exit_signal(struct task_struct *tsk) 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. + * We are cleaning up the signal_struct here. */ - exit_itimers(sig); exit_thread_group_keys(sig); kmem_cache_free(signal_cachep, sig); } @@ -578,7 +566,8 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) * is to alert stop-signal processing code when another * processor has come along and cleared the flag. */ - tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; + if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) + tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; } if ( signr && ((info->si_code & __SI_MASK) == __SI_TIMER) && @@ -678,7 +667,7 @@ static int check_kill_permission(int sig, struct siginfo *info, /* forward decl */ static void do_notify_parent_cldstop(struct task_struct *tsk, - struct task_struct *parent, + int to_self, int why); /* @@ -729,14 +718,7 @@ static void handle_stop_signal(int sig, struct task_struct *p) p->signal->group_stop_count = 0; p->signal->flags = SIGNAL_STOP_CONTINUED; spin_unlock(&p->sighand->siglock); - if (p->ptrace & PT_PTRACED) - do_notify_parent_cldstop(p, p->parent, - CLD_STOPPED); - else - do_notify_parent_cldstop( - p->group_leader, - p->group_leader->real_parent, - CLD_STOPPED); + do_notify_parent_cldstop(p, (p->ptrace & PT_PTRACED), CLD_STOPPED); spin_lock(&p->sighand->siglock); } rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending); @@ -777,14 +759,7 @@ static void handle_stop_signal(int sig, struct task_struct *p) p->signal->flags = SIGNAL_STOP_CONTINUED; p->signal->group_exit_code = 0; spin_unlock(&p->sighand->siglock); - if (p->ptrace & PT_PTRACED) - do_notify_parent_cldstop(p, p->parent, - CLD_CONTINUED); - else - do_notify_parent_cldstop( - p->group_leader, - p->group_leader->real_parent, - CLD_CONTINUED); + do_notify_parent_cldstop(p, (p->ptrace & PT_PTRACED), CLD_CONTINUED); spin_lock(&p->sighand->siglock); } else { /* @@ -950,34 +925,31 @@ force_sig_specific(int sig, struct task_struct *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; struct task_struct *t; /* - * Don't bother traced and stopped tasks (but - * SIGKILL will punch through that). - */ - 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. * * 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)) /* @@ -995,7 +967,7 @@ __group_complete_signal(int sig, struct task_struct *p) 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) /* @@ -1209,6 +1181,40 @@ kill_proc_info(int sig, struct siginfo *info, pid_t pid) return error; } +/* like kill_proc_info(), but doesn't use uid/euid of "current" */ +int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid, + uid_t uid, uid_t euid) +{ + int ret = -EINVAL; + struct task_struct *p; + + if (!valid_signal(sig)) + return ret; + + read_lock(&tasklist_lock); + p = find_task_by_pid(pid); + if (!p) { + ret = -ESRCH; + goto out_unlock; + } + if ((!info || ((unsigned long)info != 1 && + (unsigned long)info != 2 && SI_FROMUSER(info))) + && (euid != p->suid) && (euid != p->uid) + && (uid != p->suid) && (uid != p->uid)) { + ret = -EPERM; + 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 ret; +} +EXPORT_SYMBOL_GPL(kill_proc_info_as_uid); /* * kill_something_info() interprets pid in interesting ways just like kill(2). @@ -1380,16 +1386,16 @@ send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) unsigned long flags; int ret = 0; - /* - * 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. - */ BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); - read_lock(&tasklist_lock); + read_lock(&tasklist_lock); + + if (unlikely(p->flags & PF_EXITING)) { + ret = -1; + goto out_err; + } + spin_lock_irqsave(&p->sighand->siglock, flags); - + if (unlikely(!list_empty(&q->list))) { /* * If an SI_TIMER entry is already queue just increment @@ -1399,7 +1405,7 @@ send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) BUG(); q->info.si_overrun++; goto out; - } + } /* Short-circuit ignored signals. */ if (sig_ignored(p, sig)) { ret = 1; @@ -1414,8 +1420,10 @@ send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) out: spin_unlock_irqrestore(&p->sighand->siglock, flags); +out_err: read_unlock(&tasklist_lock); - return(ret); + + return ret; } int @@ -1542,14 +1550,20 @@ void do_notify_parent(struct task_struct *tsk, int sig) spin_unlock_irqrestore(&psig->siglock, flags); } -static void -do_notify_parent_cldstop(struct task_struct *tsk, struct task_struct *parent, - int why) +static void do_notify_parent_cldstop(struct task_struct *tsk, int to_self, int why) { struct siginfo info; unsigned long flags; + struct task_struct *parent; struct sighand_struct *sighand; + if (to_self) + parent = tsk->parent; + else { + tsk = tsk->group_leader; + parent = tsk->real_parent; + } + info.si_signo = SIGCHLD; info.si_errno = 0; info.si_pid = tsk->pid; @@ -1618,8 +1632,7 @@ static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info) !(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); + do_notify_parent_cldstop(current, 1, CLD_TRAPPED); read_unlock(&tasklist_lock); schedule(); } else { @@ -1668,25 +1681,25 @@ void ptrace_notify(int exit_code) static void finish_stop(int stop_count) { + int to_self; + /* * 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, current->parent, - CLD_STOPPED); - 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, - CLD_STOPPED); - read_unlock(&tasklist_lock); - } + if (stop_count < 0 || (current->ptrace & PT_PTRACED)) + to_self = 1; + else if (stop_count == 0) + to_self = 0; + else + goto out; + read_lock(&tasklist_lock); + do_notify_parent_cldstop(current, to_self, CLD_STOPPED); + read_unlock(&tasklist_lock); + +out: schedule(); /* * Now we don't run again until continued. @@ -1773,7 +1786,8 @@ do_signal_stop(int signr) * stop is always done with the siglock held, * so this check has no races. */ - if (t->state < TASK_STOPPED) { + if (!t->exit_state && + !(t->state & (TASK_STOPPED|TASK_TRACED))) { stop_count++; signal_wake_up(t, 0); } @@ -2228,8 +2242,7 @@ sys_rt_sigtimedwait(const sigset_t __user *uthese, recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); - current->state = TASK_INTERRUPTIBLE; - timeout = schedule_timeout(timeout); + timeout = schedule_timeout_interruptible(timeout); try_to_freeze(); spin_lock_irq(¤t->sighand->siglock); |