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authorDavide Libenzi <davidel@xmailserver.org>2006-10-11 01:21:44 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-11 11:14:21 -0700
commitb611967de4dc5c52049676c4369dcac622a7cdfe (patch)
tree8c19038c8bbaa4851dcb99bed33707deaf5170d1 /fs/eventpoll.c
parent0f836e5fecf59d0d0353e9af11fd14a32a3001ae (diff)
[PATCH] epoll_pwait()
Implement the epoll_pwait system call, that extend the event wait mechanism with the same logic ppoll and pselect do. The definition of epoll_pwait is: int epoll_pwait(int epfd, struct epoll_event *events, int maxevents, int timeout, const sigset_t *sigmask, size_t sigsetsize); The difference between the vanilla epoll_wait and epoll_pwait is that the latter allows the caller to specify a signal mask to be set while waiting for events. Hence epoll_pwait will wait until either one monitored event, or an unmasked signal happen. If sigmask is NULL, the epoll_pwait system call will act exactly like epoll_wait. For the POSIX definition of pselect, information is available here: http://www.opengroup.org/onlinepubs/009695399/functions/select.html Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Andi Kleen <ak@muc.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/eventpoll.c')
-rw-r--r--fs/eventpoll.c56
1 files changed, 53 insertions, 3 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 557d5b614fae..ae228ec54e94 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -105,6 +105,8 @@
/* Maximum msec timeout value storeable in a long int */
#define EP_MAX_MSTIMEO min(1000ULL * MAX_SCHEDULE_TIMEOUT / HZ, (LONG_MAX - 999ULL) / HZ)
+#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))
+
struct epoll_filefd {
struct file *file;
@@ -497,7 +499,7 @@ void eventpoll_release_file(struct file *file)
*/
asmlinkage long sys_epoll_create(int size)
{
- int error, fd;
+ int error, fd = -1;
struct eventpoll *ep;
struct inode *inode;
struct file *file;
@@ -640,7 +642,6 @@ eexit_1:
return error;
}
-#define MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))
/*
* Implement the event wait interface for the eventpoll file. It is the kernel
@@ -657,7 +658,7 @@ asmlinkage long sys_epoll_wait(int epfd, struct epoll_event __user *events,
current, epfd, events, maxevents, timeout));
/* The maximum number of event must be greater than zero */
- if (maxevents <= 0 || maxevents > MAX_EVENTS)
+ if (maxevents <= 0 || maxevents > EP_MAX_EVENTS)
return -EINVAL;
/* Verify that the area passed by the user is writeable */
@@ -699,6 +700,55 @@ eexit_1:
}
+#ifdef TIF_RESTORE_SIGMASK
+
+/*
+ * Implement the event wait interface for the eventpoll file. It is the kernel
+ * part of the user space epoll_pwait(2).
+ */
+asmlinkage long sys_epoll_pwait(int epfd, struct epoll_event __user *events,
+ int maxevents, int timeout, const sigset_t __user *sigmask,
+ size_t sigsetsize)
+{
+ int error;
+ 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(sigset_t))
+ return -EINVAL;
+ if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
+ return -EFAULT;
+ sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP));
+ sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
+ }
+
+ error = 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 (error == -EINTR) {
+ memcpy(&current->saved_sigmask, &sigsaved,
+ sizeof(sigsaved));
+ set_thread_flag(TIF_RESTORE_SIGMASK);
+ } else
+ sigprocmask(SIG_SETMASK, &sigsaved, NULL);
+ }
+
+ return error;
+}
+
+#endif /* #ifdef TIF_RESTORE_SIGMASK */
+
+
/*
* Creates the file descriptor to be used by the epoll interface.
*/