diff options
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 2662 |
1 files changed, 2662 insertions, 0 deletions
diff --git a/kernel/signal.c b/kernel/signal.c new file mode 100644 index 000000000000..f00a1d610f0b --- /dev/null +++ b/kernel/signal.c @@ -0,0 +1,2662 @@ +/* + * linux/kernel/signal.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson + * + * 2003-06-02 Jim Houston - Concurrent Computer Corp. + * Changes to use preallocated sigqueue structures + * to allow signals to be sent reliably. + */ + +#include <linux/config.h> +#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/tty.h> +#include <linux/binfmts.h> +#include <linux/security.h> +#include <linux/syscalls.h> +#include <linux/ptrace.h> +#include <linux/posix-timers.h> +#include <asm/param.h> +#include <asm/uaccess.h> +#include <asm/unistd.h> +#include <asm/siginfo.h> + +/* + * SLAB caches for signal bits. + */ + +static kmem_cache_t *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 + +#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 ) + +#define SIG_KERNEL_IGNORE_MASK (\ + M(SIGCONT) | M(SIGCHLD) | M(SIGWINCH) | M(SIGURG) ) + +#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)) + +#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)) + +#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) + +static int sig_ignored(struct task_struct *t, int sig) +{ + 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)) + 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)); +} + +/* + * Re-calculate pending state from the set of locally pending + * signals, globally pending signals, and blocked signals. + */ +static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) +{ + unsigned long ready; + long i; + + switch (_NSIG_WORDS) { + default: + for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) + ready |= signal->sig[i] &~ blocked->sig[i]; + break; + + case 4: ready = signal->sig[3] &~ blocked->sig[3]; + ready |= signal->sig[2] &~ blocked->sig[2]; + ready |= signal->sig[1] &~ blocked->sig[1]; + ready |= signal->sig[0] &~ blocked->sig[0]; + break; + + case 2: ready = signal->sig[1] &~ blocked->sig[1]; + ready |= signal->sig[0] &~ blocked->sig[0]; + break; + + case 1: ready = signal->sig[0] &~ blocked->sig[0]; + } + return ready != 0; +} + +#define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) + +fastcall void recalc_sigpending_tsk(struct task_struct *t) +{ + if (t->signal->group_stop_count > 0 || + PENDING(&t->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); +} + +void recalc_sigpending(void) +{ + recalc_sigpending_tsk(current); +} + +/* Given the mask, find the first available signal that should be serviced. */ + +static 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; + 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; + } + 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 + break; + sig += ffz(~x); + break; + + case 1: if ((x = *s &~ *m) != 0) + sig = ffz(~x) + 1; + break; + } + + return sig; +} + +static struct sigqueue *__sigqueue_alloc(struct task_struct *t, unsigned int __nocast flags, + int override_rlimit) +{ + struct sigqueue *q = NULL; + + 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 (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); + } + return(q); +} + +static inline 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); +} + +static void flush_sigqueue(struct sigpending *queue) +{ + struct sigqueue *q; + + sigemptyset(&queue->signal); + while (!list_empty(&queue->list)) { + q = list_entry(queue->list.next, struct sigqueue , list); + list_del_init(&q->list); + __sigqueue_free(q); + } +} + +/* + * Flush all pending signals for a task. + */ + +void +flush_signals(struct task_struct *t) +{ + unsigned long flags; + + spin_lock_irqsave(&t->sighand->siglock, flags); + clear_tsk_thread_flag(t,TIF_SIGPENDING); + flush_sigqueue(&t->pending); + flush_sigqueue(&t->signal->shared_pending); + spin_unlock_irqrestore(&t->sighand->siglock, flags); +} + +/* + * 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); + 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; + 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; + /* + * Accumulate here the counters for all threads but the + * group leader as they die, so they can be added into + * the process-wide totals when those are taken. + * The group leader stays around as a zombie as long + * as there are other threads. When it gets reaped, + * the exit.c code will add its counts into these totals. + * We won't ever get here for the group leader, since it + * will have been the last reference on the signal_struct. + */ + 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. */ + } + 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); + exit_thread_group_keys(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. + */ + +void +flush_signal_handlers(struct task_struct *t, int force_default) +{ + int i; + struct k_sigaction *ka = &t->sighand->action[0]; + for (i = _NSIG ; i != 0 ; i--) { + if (force_default || ka->sa.sa_handler != SIG_IGN) + ka->sa.sa_handler = SIG_DFL; + ka->sa.sa_flags = 0; + sigemptyset(&ka->sa.sa_mask); + ka++; + } +} + + +/* 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 + * sent/acted upon. If the notifier routine returns non-zero, then the + * signal will be acted upon after all. If the notifier routine returns 0, + * then then signal will be blocked. Only one block per process is + * allowed. priv is a pointer to private data that the notifier routine + * can use to determine if the signal should be blocked or not. */ + +void +block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) +{ + unsigned long flags; + + spin_lock_irqsave(¤t->sighand->siglock, flags); + current->notifier_mask = mask; + current->notifier_data = priv; + current->notifier = notifier; + spin_unlock_irqrestore(¤t->sighand->siglock, flags); +} + +/* Notify the system that blocking has ended. */ + +void +unblock_all_signals(void) +{ + unsigned long flags; + + spin_lock_irqsave(¤t->sighand->siglock, flags); + current->notifier = NULL; + current->notifier_data = NULL; + recalc_sigpending(); + spin_unlock_irqrestore(¤t->sighand->siglock, flags); +} + +static inline int 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 + * there is another siginfo for the same signal. + */ + list_for_each_entry(q, &list->list, list) { + if (q->info.si_signo == sig) { + if (first) { + still_pending = 1; + break; + } + first = q; + } + } + if (first) { + 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_pid = 0; + info->si_uid = 0; + } + return 1; +} + +static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, + siginfo_t *info) +{ + int sig = 0; + + sig = next_signal(pending, mask); + if (sig) { + if (current->notifier) { + if (sigismember(current->notifier_mask, sig)) { + if (!(current->notifier)(current->notifier_data)) { + clear_thread_flag(TIF_SIGPENDING); + return 0; + } + } + } + + if (!collect_signal(sig, pending, info)) + sig = 0; + + } + recalc_sigpending(); + + return sig; +} + +/* + * Dequeue a signal and return the element to the caller, which is + * expected to free it. + * + * All callers have to hold the siglock. + */ +int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) +{ + int signr = __dequeue_signal(&tsk->pending, mask, info); + 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; +} + +/* + * Tell a process that it has a new active signal.. + * + * NOTE! we rely on the previous spin_lock to + * lock interrupts for us! We can only be called with + * "siglock" held, and the local interrupt must + * have been disabled when that got acquired! + * + * No need to set need_resched since signal event passing + * goes through ->blocked + */ +void signal_wake_up(struct task_struct *t, int resume) +{ + unsigned int mask; + + 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 + * 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; + 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. + */ +static int rm_from_queue(unsigned long mask, struct sigpending *s) +{ + struct sigqueue *q, *n; + + if (!sigtestsetmask(&s->signal, mask)) + return 0; + + sigdelsetmask(&s->signal, mask); + list_for_each_entry_safe(q, n, &s->list, list) { + if (q->info.si_signo < SIGRTMIN && + (mask & sigmask(q->info.si_signo))) { + list_del_init(&q->list); + __sigqueue_free(q); + } + } + return 1; +} + +/* + * Bad permissions for sending the signal + */ +static int check_kill_permission(int sig, struct siginfo *info, + struct task_struct *t) +{ + int error = -EINVAL; + if (sig < 0 || sig > _NSIG) + return error; + error = -EPERM; + if ((!info || ((unsigned long)info != 1 && + (unsigned long)info != 2 && SI_FROMUSER(info))) + && ((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)) + return error; + return security_task_kill(t, info, sig); +} + +/* forward decl */ +static void do_notify_parent_cldstop(struct task_struct *tsk, + struct task_struct *parent, + int why); + +/* + * 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. + */ +static void handle_stop_signal(int sig, struct task_struct *p) +{ + 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. + */ + rm_from_queue(sigmask(SIGCONT), &p->signal->shared_pending); + t = p; + do { + rm_from_queue(sigmask(SIGCONT), &t->pending); + t = next_thread(t); + } while (t != p); + } else if (sig == SIGCONT) { + /* + * 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); + 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); + spin_lock(&p->sighand->siglock); + } + rm_from_queue(SIG_KERNEL_STOP_MASK, &p->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 + * we post the signal, in case it was the only + * thread eligible to run the signal handler--then + * it must not do anything between resuming and + * 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. + * + * Wake up the stopped thread _after_ setting + * TIF_SIGPENDING + */ + 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); + + 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); + 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); + 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 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) + 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 && + ((unsigned long) info < 2 || + info->si_code >= 0))); + if (q) { + list_add_tail(&q->list, &signals->list); + switch ((unsigned long) info) { + case 0: + 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: + 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 (sig >= SIGRTMIN && info && (unsigned long)info != 1 + && 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: + sigaddset(&signals->signal, sig); + return ret; +} + +#define LEGACY_QUEUE(sigptr, sig) \ + (((sig) < SIGRTMIN) && sigismember(&(sigptr)->signal, (sig))) + + +static int +specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) +{ + int ret = 0; + + if (!irqs_disabled()) + BUG(); + assert_spin_locked(&t->sighand->siglock); + + 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(t, sig)) + goto out; + + /* 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; + + ret = send_signal(sig, info, t, &t->pending); + if (!ret && !sigismember(&t->blocked, sig)) + signal_wake_up(t, sig == SIGKILL); +out: + return ret; +} + +/* + * Force a signal that the process can't ignore: if necessary + * we unblock the signal and change any SIG_IGN to SIG_DFL. + */ + +int +force_sig_info(int sig, struct siginfo *info, struct task_struct *t) +{ + unsigned long int flags; + int ret; + + 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); + } + 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) +{ + 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); +} + +/* + * 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. + */ +#define wants_signal(sig, p, mask) \ + (!sigismember(&(p)->blocked, sig) \ + && !((p)->state & mask) \ + && !((p)->flags & PF_EXITING) \ + && (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)) + 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; + BUG_ON(t->tgid != p->tgid); + + while (!wants_signal(sig, t, mask)) { + 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); + + 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; + + 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. + */ +void zap_other_threads(struct task_struct *p) +{ + 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; + + 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! + */ +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); + } + + return ret; +} + +/* + * kill_pg_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) +{ + struct task_struct *p = NULL; + int retval, success; + + if (pgrp <= 0) + return -EINVAL; + + success = 0; + retval = -ESRCH; + do_each_task_pid(pgrp, PIDTYPE_PGID, p) { + int err = group_send_sig_info(sig, info, p); + success |= !err; + retval = err; + } while_each_task_pid(pgrp, PIDTYPE_PGID, p); + return success ? 0 : retval; +} + +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_proc_info(int sig, struct siginfo *info, pid_t pid) +{ + int error; + struct task_struct *p; + + read_lock(&tasklist_lock); + p = find_task_by_pid(pid); + error = -ESRCH; + if (p) + error = group_send_sig_info(sig, info, p); + read_unlock(&tasklist_lock); + return error; +} + + +/* + * kill_something_info() interprets pid in interesting ways just like kill(2). + * + * POSIX specifies that kill(-1,sig) is unspecified, but what we have + * is probably wrong. Should make it like BSD or SYSV. + */ + +static int kill_something_info(int sig, struct siginfo *info, int pid) +{ + if (!pid) { + return kill_pg_info(sig, info, process_group(current)); + } else if (pid == -1) { + 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) { + 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); + } +} + +/* + * 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 (sig < 0 || sig > _NSIG) + 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; +} + +int +send_sig(int sig, struct task_struct *p, int priv) +{ + return send_sig_info(sig, (void*)(long)(priv != 0), 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) +{ + force_sig_info(sig, (void*)1L, 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 +force_sigsegv(int sig, struct task_struct *p) +{ + if (sig == SIGSEGV) { + unsigned long flags; + spin_lock_irqsave(&p->sighand->siglock, flags); + p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; + spin_unlock_irqrestore(&p->sighand->siglock, flags); + } + force_sig(SIGSEGV, p); + return 0; +} + +int +kill_pg(pid_t pgrp, int sig, int priv) +{ + return kill_pg_info(sig, (void *)(long)(priv != 0), pgrp); +} + +int +kill_proc(pid_t pid, int sig, int priv) +{ + return kill_proc_info(sig, (void *)(long)(priv != 0), pid); +} + +/* + * These functions support sending signals using preallocated sigqueue + * structures. This is needed "because realtime applications cannot + * afford to lose notifications of asynchronous events, like timer + * expirations or I/O completions". In the case of Posix Timers + * we allocate the sigqueue structure from the timer_create. If this + * allocation fails we are able to report the failure to the application + * with an EAGAIN error. + */ + +struct sigqueue *sigqueue_alloc(void) +{ + struct sigqueue *q; + + if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0))) + q->flags |= SIGQUEUE_PREALLOC; + return(q); +} + +void sigqueue_free(struct sigqueue *q) +{ + unsigned long flags; + BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); + /* + * If the signal is still pending remove it from the + * pending queue. + */ + if (unlikely(!list_empty(&q->list))) { + read_lock(&tasklist_lock); + spin_lock_irqsave(q->lock, flags); + if (!list_empty(&q->list)) + list_del_init(&q->list); + spin_unlock_irqrestore(q->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) +{ + 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); + spin_lock_irqsave(&p->sighand->siglock, flags); + + 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(); + 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); +} + +int +send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) +{ + unsigned long flags; + int ret = 0; + + BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); + read_lock(&tasklist_lock); + spin_lock_irqsave(&p->sighand->siglock, flags); + handle_stop_signal(sig, p); + + /* Short-circuit ignored signals. */ + if (sig_ignored(p, sig)) { + ret = 1; + goto out; + } + + 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. + */ + if (q->info.si_code != SI_TIMER) + BUG(); + 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. + */ + 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); +out: + spin_unlock_irqrestore(&p->sighand->siglock, flags); + read_unlock(&tasklist_lock); + 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. + */ + +void do_notify_parent(struct task_struct *tsk, int sig) +{ + struct siginfo info; + unsigned long flags; + struct sighand_struct *psig; + + BUG_ON(sig == -1); + + /* do_notify_parent_cldstop should have been called instead. */ + BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED)); + + BUG_ON(!tsk->ptrace && + (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; + + /* 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_status = tsk->exit_code & 0x7f; + if (tsk->exit_code & 0x80) + info.si_code = CLD_DUMPED; + else if (tsk->exit_code & 0x7f) + info.si_code = CLD_KILLED; + else { + info.si_code = CLD_EXITED; + info.si_status = tsk->exit_code >> 8; + } + + psig = tsk->parent->sighand; + spin_lock_irqsave(&psig->siglock, flags); + if (sig == SIGCHLD && + (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || + (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { + /* + * We are exiting and our parent doesn't care. POSIX.1 + * defines special semantics for setting SIGCHLD to SIG_IGN + * or setting the SA_NOCLDWAIT flag: we should be reaped + * automatically and not left for our parent's wait4 call. + * Rather than having the parent do it as a magic kind of + * signal handler, we just set this to tell do_exit that we + * can be cleaned up without becoming a zombie. Note that + * we still call __wake_up_parent in this case, because a + * blocked sys_wait4 might now return -ECHILD. + * + * Whether we send SIGCHLD or not for SA_NOCLDWAIT + * is implementation-defined: we do (if you don't want + * it, just use SIG_IGN instead). + */ + tsk->exit_signal = -1; + if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) + sig = 0; + } + if (sig > 0 && sig <= _NSIG) + __group_send_sig_info(sig, &info, tsk->parent); + __wake_up_parent(tsk, tsk->parent); + spin_unlock_irqrestore(&psig->siglock, flags); +} + +static void +do_notify_parent_cldstop(struct task_struct *tsk, struct task_struct *parent, + int why) +{ + struct siginfo info; + unsigned long flags; + struct sighand_struct *sighand; + + info.si_signo = SIGCHLD; + info.si_errno = 0; + info.si_pid = tsk->pid; + info.si_uid = tsk->uid; + + /* 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_code = why; + switch (why) { + case CLD_CONTINUED: + info.si_status = SIGCONT; + break; + case CLD_STOPPED: + info.si_status = tsk->signal->group_exit_code & 0x7f; + break; + case CLD_TRAPPED: + info.si_status = tsk->exit_code & 0x7f; + break; + default: + BUG(); + } + + sighand = parent->sighand; + spin_lock_irqsave(&sighand->siglock, flags); + if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && + !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) + __group_send_sig_info(SIGCHLD, &info, parent); + /* + * Even if SIGCHLD is not generated, we must wake up wait4 calls. + */ + __wake_up_parent(tsk, parent); + spin_unlock_irqrestore(&sighand->siglock, flags); +} + +/* + * This must be called with current->sighand->siglock held. + * + * This should be the path for all ptrace stops. + * We always set current->last_siginfo while stopped here. + * That makes it a way to test a stopped process for + * being ptrace-stopped vs being job-control-stopped. + * + * If we actually decide not to stop at all because the tracer is gone, + * we leave nostop_code in current->exit_code. + */ +static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info) +{ + /* + * 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; + + current->last_siginfo = info; + current->exit_code = exit_code; + + /* Let the debugger run. */ + set_current_state(TASK_TRACED); + spin_unlock_irq(¤t->sighand->siglock); + read_lock(&tasklist_lock); + 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 + * last_siginfo, so that we are sure to have synchronized with + * any signal-sending on another CPU that wants to examine it. + */ + spin_lock_irq(¤t->sighand->siglock); + current->last_siginfo = NULL; + + /* + * Queued signals ignored us while we were stopped for tracing. + * So check for any that we should take before resuming user mode. + */ + recalc_sigpending(); +} + +void ptrace_notify(int exit_code) +{ + siginfo_t info; + + BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); + + memset(&info, 0, sizeof info); + info.si_signo = SIGTRAP; + info.si_code = exit_code; + info.si_pid = current->pid; + info.si_uid = current->uid; + + /* Let the debugger run. */ + spin_lock_irq(¤t->sighand->siglock); + ptrace_stop(exit_code, 0, &info); + spin_unlock_irq(¤t->sighand->siglock); +} + +#ifndef HAVE_ARCH_GET_SIGNAL_TO_DELIVER + +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, 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); + } + + 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. + * Returns nonzero if we've actually stopped and released the siglock. + * Returns zero if we didn't stop and still hold the siglock. + */ +static int +do_signal_stop(int signr) +{ + struct signal_struct *sig = current->signal; + struct sighand_struct *sighand = current->sighand; + int stop_count = -1; + + 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); + if (stop_count == 0) + sig->flags = SIGNAL_STOP_STOPPED; + spin_unlock_irq(&sighand->siglock); + } + else if (thread_group_empty(current)) { + /* + * Lock must be held through transition to stopped state. + */ + current->exit_code = current->signal->group_exit_code = signr; + set_current_state(TASK_STOPPED); + sig->flags = SIGNAL_STOP_STOPPED; + spin_unlock_irq(&sighand->siglock); + } + 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. + */ + 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); + + if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED)) { + /* + * 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. + */ + read_unlock(&tasklist_lock); + return 0; + } + + 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); + if (stop_count == 0) + sig->flags = SIGNAL_STOP_STOPPED; + + spin_unlock_irq(&sighand->siglock); + read_unlock(&tasklist_lock); + } + + 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 inline int handle_group_stop(void) +{ + int stop_count; + + 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; + } + + 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; + + /* + * 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; +} + +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; + +relock: + spin_lock_irq(¤t->sighand->siglock); + for (;;) { + struct k_sigaction *ka; + + if (unlikely(current->signal->group_stop_count > 0) && + 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); + + /* 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; + + 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; + } + + /* If the (new) signal is now blocked, requeue it. */ + if (sigismember(¤t->blocked, signr)) { + specific_send_sig_info(signr, info, current); + continue; + } + } + + 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. */ + *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) + continue; + + if (sig_kernel_stop(signr)) { + /* + * The default action is to stop all threads in + * the thread group. The job control signals + * do nothing in an orphaned pgrp, but SIGSTOP + * always works. Note that siglock needs to be + * dropped during the call to is_orphaned_pgrp() + * because of lock ordering with tasklist_lock. + * This allows an intervening SIGCONT to be posted. + * We need to check for that and bail out if necessary. + */ + if (signr != SIGSTOP) { + spin_unlock_irq(¤t->sighand->siglock); + + /* signals can be posted during this window */ + + if (is_orphaned_pgrp(process_group(current))) + goto relock; + + spin_lock_irq(¤t->sighand->siglock); + } + + 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); + + /* + * Anything else is fatal, maybe with a core dump. + */ + current->flags |= PF_SIGNALED; + if (sig_kernel_coredump(signr)) { + /* + * If it was able to dump core, this kills all + * other threads in the group and synchronizes with + * their demise. If we lost the race with another + * thread getting here, it set group_exit_code + * first and our do_group_exit call below will use + * that value and ignore the one we pass it. + */ + do_coredump((long)signr, signr, regs); + } + + /* + * Death signals, no core dump. + */ + do_group_exit(signr); + /* 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(kill_pg); +EXPORT_SYMBOL(kill_proc); +EXPORT_SYMBOL(ptrace_notify); +EXPORT_SYMBOL(send_sig); +EXPORT_SYMBOL(send_sig_info); +EXPORT_SYMBOL(sigprocmask); +EXPORT_SYMBOL(block_all_signals); +EXPORT_SYMBOL(unblock_all_signals); + + +/* + * System call entry points. + */ + +asmlinkage long sys_restart_syscall(void) +{ + struct restart_block *restart = ¤t_thread_info()->restart_block; + return restart->fn(restart); +} + +long do_no_restart_syscall(struct restart_block *param) +{ + return -EINTR; +} + +/* + * We don't need to get the kernel lock - this is all local to this + * particular thread.. (and that's good, because this is _heavily_ + * used by various programs) + */ + +/* + * This is also useful for kernel threads that want to temporarily + * (or permanently) block certain signals. + * + * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel + * interface happily blocks "unblockable" signals like SIGKILL + * and friends. + */ +int sigprocmask(int how, sigset_t *set, sigset_t *oldset) +{ + int error; + sigset_t old_block; + + spin_lock_irq(¤t->sighand->siglock); + old_block = current->blocked; + error = 0; + switch (how) { + case SIG_BLOCK: + sigorsets(¤t->blocked, ¤t->blocked, set); + break; + case SIG_UNBLOCK: + signandsets(¤t->blocked, ¤t->blocked, set); + break; + case SIG_SETMASK: + current->blocked = *set; + break; + default: + error = -EINVAL; + } + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + if (oldset) + *oldset = old_block; + return error; +} + +asmlinkage long +sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize) +{ + int error = -EINVAL; + sigset_t old_set, new_set; + + /* XXX: Don't preclude handling different sized sigset_t's. */ + if (sigsetsize != sizeof(sigset_t)) + goto out; + + if (set) { + error = -EFAULT; + if (copy_from_user(&new_set, set, sizeof(*set))) + goto out; + sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); + + error = sigprocmask(how, &new_set, &old_set); + if (error) + goto out; + if (oset) + goto set_old; + } else if (oset) { + spin_lock_irq(¤t->sighand->siglock); + old_set = current->blocked; + spin_unlock_irq(¤t->sighand->siglock); + + set_old: + error = -EFAULT; + if (copy_to_user(oset, &old_set, sizeof(*oset))) + goto out; + } + error = 0; +out: + return error; +} + +long do_sigpending(void __user *set, unsigned long sigsetsize) +{ + long error = -EINVAL; + sigset_t pending; + + if (sigsetsize > sizeof(sigset_t)) + goto out; + + spin_lock_irq(¤t->sighand->siglock); + sigorsets(&pending, ¤t->pending.signal, + ¤t->signal->shared_pending.signal); + spin_unlock_irq(¤t->sighand->siglock); + + /* Outside the lock because only this thread touches it. */ + sigandsets(&pending, ¤t->blocked, &pending); + + error = -EFAULT; + if (!copy_to_user(set, &pending, sigsetsize)) + error = 0; + +out: + return error; +} + +asmlinkage long +sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize) +{ + return do_sigpending(set, sigsetsize); +} + +#ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER + +int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) +{ + int err; + + if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) + return -EFAULT; + if (from->si_code < 0) + return __copy_to_user(to, from, sizeof(siginfo_t)) + ? -EFAULT : 0; + /* + * If you change siginfo_t structure, please be sure + * this code is fixed accordingly. + * 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. + */ + err = __put_user(from->si_signo, &to->si_signo); + err |= __put_user(from->si_errno, &to->si_errno); + err |= __put_user((short)from->si_code, &to->si_code); + switch (from->si_code & __SI_MASK) { + case __SI_KILL: + err |= __put_user(from->si_pid, &to->si_pid); + err |= __put_user(from->si_uid, &to->si_uid); + break; + case __SI_TIMER: + err |= __put_user(from->si_tid, &to->si_tid); + err |= __put_user(from->si_overrun, &to->si_overrun); + err |= __put_user(from->si_ptr, &to->si_ptr); + break; + case __SI_POLL: + err |= __put_user(from->si_band, &to->si_band); + err |= __put_user(from->si_fd, &to->si_fd); + break; + case __SI_FAULT: + err |= __put_user(from->si_addr, &to->si_addr); +#ifdef __ARCH_SI_TRAPNO + err |= __put_user(from->si_trapno, &to->si_trapno); +#endif + break; + case __SI_CHLD: + err |= __put_user(from->si_pid, &to->si_pid); + err |= __put_user(from->si_uid, &to->si_uid); + err |= __put_user(from->si_status, &to->si_status); + err |= __put_user(from->si_utime, &to->si_utime); + err |= __put_user(from->si_stime, &to->si_stime); + break; + case __SI_RT: /* This is not generated by the kernel as of now. */ + case __SI_MESGQ: /* But this is */ + err |= __put_user(from->si_pid, &to->si_pid); + err |= __put_user(from->si_uid, &to->si_uid); + err |= __put_user(from->si_ptr, &to->si_ptr); + break; + default: /* this is just in case for now ... */ + err |= __put_user(from->si_pid, &to->si_pid); + err |= __put_user(from->si_uid, &to->si_uid); + break; + } + return err; +} + +#endif + +asmlinkage long +sys_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; + struct timespec ts; + siginfo_t info; + long timeout = 0; + + /* XXX: Don't preclude handling different sized sigset_t's. */ + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + + if (copy_from_user(&these, uthese, sizeof(these))) + return -EFAULT; + + /* + * Invert the set of allowed signals to get those we + * want to block. + */ + sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); + signotset(&these); + + if (uts) { + if (copy_from_user(&ts, uts, sizeof(ts))) + return -EFAULT; + if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 + || ts.tv_sec < 0) + return -EINVAL; + } + + spin_lock_irq(¤t->sighand->siglock); + sig = dequeue_signal(current, &these, &info); + if (!sig) { + timeout = MAX_SCHEDULE_TIMEOUT; + if (uts) + timeout = (timespec_to_jiffies(&ts) + + (ts.tv_sec || ts.tv_nsec)); + + if (timeout) { + /* None ready -- temporarily unblock those we're + * interested while we are sleeping in so that we'll + * be awakened when they arrive. */ + current->real_blocked = current->blocked; + sigandsets(¤t->blocked, ¤t->blocked, &these); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + 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; + siginitset(¤t->real_blocked, 0); + recalc_sigpending(); + } + } + spin_unlock_irq(¤t->sighand->siglock); + + if (sig) { + ret = sig; + if (uinfo) { + if (copy_siginfo_to_user(uinfo, &info)) + ret = -EFAULT; + } + } else { + ret = -EAGAIN; + if (timeout) + ret = -EINTR; + } + + return ret; +} + +asmlinkage long +sys_kill(int 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; + + return kill_something_info(sig, &info, pid); +} + +/** + * 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) +{ + struct siginfo info; + int error; + struct task_struct *p; + + /* This is only valid for single tasks */ + if (pid <= 0 || tgid <= 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 && (p->tgid == 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); + } + } + read_unlock(&tasklist_lock); + return error; +} + +/* + * 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; +} + +asmlinkage long +sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo) +{ + siginfo_t info; + + if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) + return -EFAULT; + + /* 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; + + /* POSIX.1b doesn't mention process groups. */ + return kill_proc_info(sig, &info, pid); +} + +int +do_sigaction(int sig, const struct k_sigaction *act, struct k_sigaction *oact) +{ + struct k_sigaction *k; + + if (sig < 1 || sig > _NSIG || (act && sig_kernel_only(sig))) + return -EINVAL; + + 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; + + if (act) { + /* + * POSIX 3.3.1.3: + * "Setting a signal action to SIG_IGN for a signal that is + * pending shall cause the pending signal to be discarded, + * whether or not it is blocked." + * + * "Setting a signal action to SIG_DFL for a signal that is + * pending and whose default action is to ignore the signal + * (for example, SIGCHLD), shall cause the pending signal to + * be discarded, whether or not it is blocked" + */ + if (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. + */ + 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); + do { + rm_from_queue(sigmask(sig), &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); + return 0; +} + +int +do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) +{ + 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); + } + + if (uss) { + void __user *ss_sp; + size_t ss_size; + 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)) + goto out; + + error = -EPERM; + if (on_sig_stack(sp)) + goto out; + + error = -EINVAL; + /* + * + * Note - this code used to test ss_flags incorrectly + * old code may have been written using ss_flags==0 + * to mean ss_flags==SS_ONSTACK (as this was the only + * way that worked) - this fix preserves that older + * mechanism + */ + if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) + goto out; + + if (ss_flags == SS_DISABLE) { + ss_size = 0; + ss_sp = NULL; + } else { + error = -ENOMEM; + if (ss_size < MINSIGSTKSZ) + goto out; + } + + current->sas_ss_sp = (unsigned long) ss_sp; + current->sas_ss_size = ss_size; + } + + if (uoss) { + error = -EFAULT; + if (copy_to_user(uoss, &oss, sizeof(oss))) + goto out; + } + + error = 0; +out: + return error; +} + +#ifdef __ARCH_WANT_SYS_SIGPENDING + +asmlinkage long +sys_sigpending(old_sigset_t __user *set) +{ + return do_sigpending(set, sizeof(*set)); +} + +#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) +{ + int error; + old_sigset_t old_set, new_set; + + if (set) { + error = -EFAULT; + if (copy_from_user(&new_set, set, sizeof(*set))) + goto out; + new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); + + spin_lock_irq(¤t->sighand->siglock); + old_set = current->blocked.sig[0]; + + error = 0; + switch (how) { + default: + error = -EINVAL; + break; + case SIG_BLOCK: + sigaddsetmask(¤t->blocked, new_set); + break; + case SIG_UNBLOCK: + sigdelsetmask(¤t->blocked, new_set); + break; + case SIG_SETMASK: + current->blocked.sig[0] = new_set; + break; + } + + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + if (error) + goto out; + if (oset) + goto set_old; + } else if (oset) { + old_set = current->blocked.sig[0]; + set_old: + error = -EFAULT; + if (copy_to_user(oset, &old_set, sizeof(*oset))) + goto out; + } + error = 0; +out: + return error; +} +#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) +{ + struct k_sigaction new_sa, old_sa; + int ret = -EINVAL; + + /* XXX: Don't preclude handling different sized sigset_t's. */ + if (sigsetsize != sizeof(sigset_t)) + goto out; + + if (act) { + if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) + return -EFAULT; + } + + ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); + + if (!ret && oact) { + if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) + return -EFAULT; + } +out: + return ret; +} +#endif /* __ARCH_WANT_SYS_RT_SIGACTION */ + +#ifdef __ARCH_WANT_SYS_SGETMASK + +/* + * For backwards compatibility. Functionality superseded by sigprocmask. + */ +asmlinkage long +sys_sgetmask(void) +{ + /* SMP safe */ + return current->blocked.sig[0]; +} + +asmlinkage long +sys_ssetmask(int newmask) +{ + int old; + + spin_lock_irq(¤t->sighand->siglock); + old = current->blocked.sig[0]; + + siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| + sigmask(SIGSTOP))); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + return old; +} +#endif /* __ARCH_WANT_SGETMASK */ + +#ifdef __ARCH_WANT_SYS_SIGNAL +/* + * For backwards compatibility. Functionality superseded by sigaction. + */ +asmlinkage unsigned long +sys_signal(int sig, __sighandler_t handler) +{ + struct k_sigaction new_sa, old_sa; + int ret; + + new_sa.sa.sa_handler = handler; + new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; + + ret = do_sigaction(sig, &new_sa, &old_sa); + + return ret ? ret : (unsigned long)old_sa.sa.sa_handler; +} +#endif /* __ARCH_WANT_SYS_SIGNAL */ + +#ifdef __ARCH_WANT_SYS_PAUSE + +asmlinkage long +sys_pause(void) +{ + current->state = TASK_INTERRUPTIBLE; + schedule(); + return -ERESTARTNOHAND; +} + +#endif + +void __init signals_init(void) +{ + sigqueue_cachep = + kmem_cache_create("sigqueue", + sizeof(struct sigqueue), + __alignof__(struct sigqueue), + SLAB_PANIC, NULL, NULL); +} |