switch epoll_pwait to COMPAT_SYSCALL_DEFINE

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 47 insertions, 0 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 9fec183..495d155 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:
@@ -1940,6 +1941,52 @@ 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;