#include <linux/syscalls.h>
#include <linux/ptrace.h>
#include <linux/signal.h>
+#include <linux/signalfd.h>
#include <linux/capability.h>
#include <linux/freezer.h>
#include <linux/pid_namespace.h>
#define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
-fastcall void recalc_sigpending_tsk(struct task_struct *t)
+static int recalc_sigpending_tsk(struct task_struct *t)
{
if (t->signal->group_stop_count > 0 ||
(freezing(t)) ||
PENDING(&t->pending, &t->blocked) ||
- PENDING(&t->signal->shared_pending, &t->blocked))
+ PENDING(&t->signal->shared_pending, &t->blocked)) {
set_tsk_thread_flag(t, TIF_SIGPENDING);
- else
- clear_tsk_thread_flag(t, TIF_SIGPENDING);
+ return 1;
+ }
+ /*
+ * We must never clear the flag in another thread, or in current
+ * when it's possible the current syscall is returning -ERESTART*.
+ * So we don't clear it here, and only callers who know they should do.
+ */
+ return 0;
+}
+
+/*
+ * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
+ * This is superfluous when called on current, the wakeup is a harmless no-op.
+ */
+void recalc_sigpending_and_wake(struct task_struct *t)
+{
+ if (recalc_sigpending_tsk(t))
+ signal_wake_up(t, 0);
}
void recalc_sigpending(void)
{
- recalc_sigpending_tsk(current);
+ if (!recalc_sigpending_tsk(current))
+ clear_thread_flag(TIF_SIGPENDING);
+
}
/* Given the mask, find the first available signal that should be serviced. */
-static int
-next_signal(struct sigpending *pending, sigset_t *mask)
+int next_signal(struct sigpending *pending, sigset_t *mask)
{
unsigned long i, *s, *m, x;
int sig = 0;
spin_unlock_irqrestore(&t->sighand->siglock, flags);
}
+void ignore_signals(struct task_struct *t)
+{
+ int i;
+
+ for (i = 0; i < _NSIG; ++i)
+ t->sighand->action[i].sa.sa_handler = SIG_IGN;
+
+ flush_signals(t);
+}
+
/*
* Flush all handlers for a task.
*/
*/
int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
{
- int signr = __dequeue_signal(&tsk->pending, mask, info);
+ int signr = 0;
+
+ /* We only dequeue private signals from ourselves, we don't let
+ * signalfd steal them
+ */
+ if (tsk == current)
+ signr = __dequeue_signal(&tsk->pending, mask, info);
if (!signr) {
signr = __dequeue_signal(&tsk->signal->shared_pending,
mask, info);
}
}
}
- recalc_sigpending_tsk(tsk);
+ if (likely(tsk == current))
+ recalc_sigpending();
if (signr && unlikely(sig_kernel_stop(signr))) {
/*
* Set a marker that we have dequeued a stop signal. Our
int error = -EINVAL;
if (!valid_signal(sig))
return error;
+
+ error = audit_signal_info(sig, t); /* Let audit system see the signal */
+ if (error)
+ return error;
+
error = -EPERM;
if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info)))
&& ((sig != SIGCONT) ||
&& !capable(CAP_KILL))
return error;
- error = security_task_kill(t, info, sig, 0);
- if (!error)
- audit_signal_info(sig, t); /* Let audit system see the signal */
- return error;
+ return security_task_kill(t, info, sig, 0);
}
/* forward decl */
int ret = 0;
/*
+ * Deliver the signal to listening signalfds. This must be called
+ * with the sighand lock held.
+ */
+ signalfd_notify(t, sig);
+
+ /*
* fast-pathed signals for kernel-internal things like SIGSTOP
* or SIGKILL.
*/
#define LEGACY_QUEUE(sigptr, sig) \
(((sig) < SIGRTMIN) && sigismember(&(sigptr)->signal, (sig)))
+int print_fatal_signals;
+
+static void print_fatal_signal(struct pt_regs *regs, int signr)
+{
+ printk("%s/%d: potentially unexpected fatal signal %d.\n",
+ current->comm, current->pid, signr);
+
+#ifdef __i386__
+ printk("code at %08lx: ", regs->eip);
+ {
+ int i;
+ for (i = 0; i < 16; i++) {
+ unsigned char insn;
+
+ __get_user(insn, (unsigned char *)(regs->eip + i));
+ printk("%02x ", insn);
+ }
+ }
+#endif
+ printk("\n");
+ show_regs(regs);
+}
+
+static int __init setup_print_fatal_signals(char *str)
+{
+ get_option (&str, &print_fatal_signals);
+
+ return 1;
+}
+
+__setup("print-fatal-signals=", setup_print_fatal_signals);
static int
specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
action->sa.sa_handler = SIG_DFL;
if (blocked) {
sigdelset(&t->blocked, sig);
- recalc_sigpending_tsk(t);
+ recalc_sigpending_and_wake(t);
}
}
ret = specific_send_sig_info(sig, info, t);
if (t->exit_state)
continue;
- /*
- * We don't want to notify the parent, since we are
- * killed as part of a thread group due to another
- * thread doing an execve() or similar. So set the
- * exit signal to -1 to allow immediate reaping of
- * the process. But don't detach the thread group
- * leader.
- */
- if (t != p->group_leader)
- t->exit_signal = -1;
-
/* SIGKILL will be handled before any pending SIGSTOP */
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
ret = 1;
goto out;
}
+ /*
+ * Deliver the signal to listening signalfds. This must be called
+ * with the sighand lock held.
+ */
+ signalfd_notify(p, sig);
list_add_tail(&q->list, &p->pending.list);
sigaddset(&p->pending.signal, sig);
q->info.si_overrun++;
goto out;
}
+ /*
+ * Deliver the signal to listening signalfds. This must be called
+ * with the sighand lock held.
+ */
+ signalfd_notify(p, sig);
/*
* Put this signal on the shared-pending queue.
/*
* Queued signals ignored us while we were stopped for tracing.
* So check for any that we should take before resuming user mode.
+ * This sets TIF_SIGPENDING, but never clears it.
*/
- recalc_sigpending();
+ recalc_sigpending_tsk(current);
}
void ptrace_notify(int exit_code)
* Anything else is fatal, maybe with a core dump.
*/
current->flags |= PF_SIGNALED;
+ if ((signr != SIGKILL) && print_fatal_signals)
+ print_fatal_signal(regs, signr);
if (sig_kernel_coredump(signr)) {
/*
* If it was able to dump core, this kills all
/*
* If you change siginfo_t structure, please be sure
* this code is fixed accordingly.
+ * Please remember to update the signalfd_copyinfo() function
+ * inside fs/signalfd.c too, in case siginfo_t changes.
* It should never copy any pad contained in the structure
* to avoid security leaks, but must copy the generic
* 3 ints plus the relevant union member.
rm_from_queue_full(&mask, &t->signal->shared_pending);
do {
rm_from_queue_full(&mask, &t->pending);
- recalc_sigpending_tsk(t);
+ recalc_sigpending_and_wake(t);
t = next_thread(t);
} while (t != current);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff