1 files changed, 47 insertions, 0 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 277cc38aeda5..deecc7294a67 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -40,6 +40,7 @@
 #include <linux/atomic.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/compat.h>
 
 /*
  * LOCKING:
@@ -1998,6 +1999,52 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
         return error;
 }
 
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,
+                        struct epoll_event __user *, events,
+                        int, maxevents, int, timeout,
+                        const compat_sigset_t __user *, sigmask,
+                        compat_size_t, sigsetsize)
+{
+        long err;
+        compat_sigset_t csigmask;
+        sigset_t ksigmask, sigsaved;
+
+        /*
+         * If the caller wants a certain signal mask to be set during the wait,
+         * we apply it here.
+         */
+        if (sigmask) {
+                if (sigsetsize != sizeof(compat_sigset_t))
+                        return -EINVAL;
+                if (copy_from_user(&csigmask, sigmask, sizeof(csigmask)))
+                        return -EFAULT;
+                sigset_from_compat(&ksigmask, &csigmask);
+                sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP));
+                sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
+        }
+
+        err = sys_epoll_wait(epfd, events, maxevents, timeout);
+
+        /*
+         * If we changed the signal mask, we need to restore the original one.
+         * In case we've got a signal while waiting, we do not restore the
+         * signal mask yet, and we allow do_signal() to deliver the signal on
+         * the way back to userspace, before the signal mask is restored.
+         */
+        if (sigmask) {
+                if (err == -EINTR) {
+                        memcpy(&current->saved_sigmask, &sigsaved,
+                               sizeof(sigsaved));
+                        set_restore_sigmask();
+                } else
+                        sigprocmask(SIG_SETMASK, &sigsaved, NULL);
+        }
+
+        return err;
+}
+#endif
+
 static int __init eventpoll_init(void)
 {
         struct sysinfo si;