[PATCH] Add epoll compat_ code to fs/compat.c

IA64 and ARM-OABI are currently using their own version of epoll compat_
code.

An architecture needs epoll_event translation if alignof(u64) in 32 bit
mode is different from alignof(u64) in 64 bit mode.  If an architecture
needs epoll_event translation, it must define struct compat_epoll_event in
asm/compat.h and set CONFIG_HAVE_COMPAT_EPOLL_EVENT and use
compat_sys_epoll_ctl and compat_sys_epoll_wait.

All 64 bit architecture should use compat_sys_epoll_pwait.

[sfr: restructure and move to fs/compat.c, remove MIPS version
of compat_sys_epoll_pwait, use __put_user_unaligned]

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 119 insertions, 46 deletions

diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index 30d433f14f93..1df544c1f966 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -564,49 +564,3 @@ _sys32_clone(nabi_no_regargs struct pt_regs regs)
         return do_fork(clone_flags, newsp, &regs, 0,
                        parent_tidptr, child_tidptr);
 }
-
-/*
- * Implement the event wait interface for the eventpoll file. It is the kernel
- * part of the user space epoll_pwait(2).
- */
-asmlinkage long compat_sys_epoll_pwait(int epfd,
-        struct epoll_event __user *events, int maxevents, int timeout,
-        const compat_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 (!access_ok(VERIFY_READ, sigmask, sizeof(ksigmask)))
-                        return -EFAULT;
-                if (__copy_conv_sigset_from_user(&ksigmask, sigmask))
-                        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;
-}
diff --git a/fs/compat.c b/fs/compat.c
index 0ec70e3cee0a..040a8be38a48 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -48,6 +48,7 @@
 #include <linux/highmem.h>
 #include <linux/poll.h>
 #include <linux/mm.h>
+#include <linux/eventpoll.h>
 
 #include <net/sock.h>           /* siocdevprivate_ioctl */
 
@@ -2235,3 +2236,102 @@ long asmlinkage compat_sys_nfsservctl(int cmd, void *notused, void *notused2)
         return sys_ni_syscall();
 }
 #endif
+
+#ifdef CONFIG_EPOLL
+
+#ifdef CONFIG_HAS_COMPAT_EPOLL_EVENT
+asmlinkage long compat_sys_epoll_ctl(int epfd, int op, int fd,
+                        struct compat_epoll_event __user *event)
+{
+        long err = 0;
+        struct compat_epoll_event user;
+        struct epoll_event __user *kernel = NULL;
+
+        if (event) {
+                if (copy_from_user(&user, event, sizeof(user)))
+                        return -EFAULT;
+                kernel = compat_alloc_user_space(sizeof(struct epoll_event));
+                err |= __put_user(user.events, &kernel->events);
+                err |= __put_user(user.data, &kernel->data);
+        }
+
+        return err ? err : sys_epoll_ctl(epfd, op, fd, kernel);
+}
+
+
+asmlinkage long compat_sys_epoll_wait(int epfd,
+                        struct compat_epoll_event __user *events,
+                        int maxevents, int timeout)
+{
+        long i, ret, err = 0;
+        struct epoll_event __user *kbuf;
+        struct epoll_event ev;
+
+        if ((maxevents <= 0) ||
+                        (maxevents > (INT_MAX / sizeof(struct epoll_event))))
+                return -EINVAL;
+        kbuf = compat_alloc_user_space(sizeof(struct epoll_event) * maxevents);
+        ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout);
+        for (i = 0; i < ret; i++) {
+                err |= __get_user(ev.events, &kbuf[i].events);
+                err |= __get_user(ev.data, &kbuf[i].data);
+                err |= __put_user(ev.events, &events->events);
+                err |= __put_user_unaligned(ev.data, &events->data);
+                events++;
+        }
+
+        return err ? -EFAULT: ret;
+}
+#endif  /* CONFIG_HAS_COMPAT_EPOLL_EVENT */
+
+#ifdef TIF_RESTORE_SIGMASK
+asmlinkage long compat_sys_epoll_pwait(int epfd,
+                        struct compat_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);
+        }
+
+#ifdef CONFIG_HAS_COMPAT_EPOLL_EVENT
+        err = compat_sys_epoll_wait(epfd, events, maxevents, timeout);
+#else
+        err = sys_epoll_wait(epfd, events, maxevents, timeout);
+#endif
+
+        /*
+         * 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_thread_flag(TIF_RESTORE_SIGMASK);
+                } else
+                        sigprocmask(SIG_SETMASK, &sigsaved, NULL);
+        }
+
+        return err;
+}
+#endif /* TIF_RESTORE_SIGMASK */
+
+#endif /* CONFIG_EPOLL */
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 80b17f440ec1..ccd863dd77fa 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -234,5 +234,24 @@ asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
                 compat_ulong_t maxnode, const compat_ulong_t __user *old_nodes,
                 const compat_ulong_t __user *new_nodes);
 
+/*
+ * epoll (fs/eventpoll.c) compat bits follow ...
+ */
+#ifndef CONFIG_HAS_COMPAT_EPOLL_EVENT
+struct epoll_event;
+#define compat_epoll_event      epoll_event
+#else
+asmlinkage long compat_sys_epoll_ctl(int epfd, int op, int fd,
+                        struct compat_epoll_event __user *event);
+asmlinkage long compat_sys_epoll_wait(int epfd,
+                        struct compat_epoll_event __user *events,
+                        int maxevents, int timeout);
+#endif
+asmlinkage long compat_sys_epoll_pwait(int epfd,
+                        struct compat_epoll_event __user *events,
+                        int maxevents, int timeout,
+                        const compat_sigset_t __user *sigmask,
+                        compat_size_t sigsetsize);
+
 #endif /* CONFIG_COMPAT */
 #endif /* _LINUX_COMPAT_H */