The following patch excludes synchronous signals from being dequeued
by a signalfd. It also re-enable signalfd from fetching signals (that
are not synchronous) sent with sys_tkill() and sys_tgkill(), to the
thread that created the signalfd.
The behaviour of a signalfd will hence be:
- Does not, in any case, fetch synchronous signals
- Does fetch shared signals of the thread group of the thread that
created the signalfd
- Does fetch private signals sent using sys_tkill() or sys_tgkill(),
to the thread that created the signalfd
Signed-off-by: Davide Libenzi <[EMAIL PROTECTED]>
- Davide
---
fs/signalfd.c | 10 +++++++++-
kernel/signal.c | 6 +-----
2 files changed, 10 insertions(+), 6 deletions(-)
Index: linux-2.6.mod/fs/signalfd.c
===================================================================
--- linux-2.6.mod.orig/fs/signalfd.c 2007-06-19 18:58:15.000000000 -0700
+++ linux-2.6.mod/fs/signalfd.c 2007-06-19 19:02:57.000000000 -0700
@@ -26,6 +26,14 @@
#include <linux/anon_inodes.h>
#include <linux/signalfd.h>
+/*
+ * Signals that a signalfd should never fetch.
+ */
+#define SIGNALFD_EXCLUDE_MASK (sigmask(SIGILL) | sigmask(SIGKILL) | \
+ sigmask(SIGSTOP) | sigmask(SIGTRAP) | \
+ sigmask(SIGFPE) | sigmask(SIGSEGV) | \
+ sigmask(SIGBUS))
+
struct signalfd_ctx {
struct list_head lnk;
wait_queue_head_t wqh;
@@ -320,7 +328,7 @@
if (sizemask != sizeof(sigset_t) ||
copy_from_user(&sigmask, user_mask, sizeof(sigmask)))
return error = -EINVAL;
- sigdelsetmask(&sigmask, sigmask(SIGKILL) | sigmask(SIGSTOP));
+ sigdelsetmask(&sigmask, SIGNALFD_EXCLUDE_MASK);
signotset(&sigmask);
if (ufd == -1) {
Index: linux-2.6.mod/kernel/signal.c
===================================================================
--- linux-2.6.mod.orig/kernel/signal.c 2007-06-19 18:55:07.000000000 -0700
+++ linux-2.6.mod/kernel/signal.c 2007-06-19 18:58:43.000000000 -0700
@@ -365,11 +365,7 @@
{
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);
+ signr = __dequeue_signal(&tsk->pending, mask, info);
if (!signr) {
signr = __dequeue_signal(&tsk->signal->shared_pending,
mask, info);
-
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