File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/ipc/compat_mq.c b/ipc/compat_mq.c
new file mode 100644
index 0000000..ef6f91c
--- /dev/null
+++ b/ipc/compat_mq.c
@@ -0,0 +1,138 @@
+/*
+ *  ipc/compat_mq.c
+ *    32 bit emulation for POSIX message queue system calls
+ *
+ *    Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Author: Arnd Bergmann <arnd@arndb.de>
+ */
+
+#include <linux/compat.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/mqueue.h>
+#include <linux/syscalls.h>
+
+#include <linux/uaccess.h>
+
+struct compat_mq_attr {
+	compat_long_t mq_flags;      /* message queue flags		     */
+	compat_long_t mq_maxmsg;     /* maximum number of messages	     */
+	compat_long_t mq_msgsize;    /* maximum message size		     */
+	compat_long_t mq_curmsgs;    /* number of messages currently queued  */
+	compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
+};
+
+static inline int get_compat_mq_attr(struct mq_attr *attr,
+			const struct compat_mq_attr __user *uattr)
+{
+	if (!access_ok(VERIFY_READ, uattr, sizeof *uattr))
+		return -EFAULT;
+
+	return __get_user(attr->mq_flags, &uattr->mq_flags)
+		| __get_user(attr->mq_maxmsg, &uattr->mq_maxmsg)
+		| __get_user(attr->mq_msgsize, &uattr->mq_msgsize)
+		| __get_user(attr->mq_curmsgs, &uattr->mq_curmsgs);
+}
+
+static inline int put_compat_mq_attr(const struct mq_attr *attr,
+			struct compat_mq_attr __user *uattr)
+{
+	if (clear_user(uattr, sizeof *uattr))
+		return -EFAULT;
+
+	return __put_user(attr->mq_flags, &uattr->mq_flags)
+		| __put_user(attr->mq_maxmsg, &uattr->mq_maxmsg)
+		| __put_user(attr->mq_msgsize, &uattr->mq_msgsize)
+		| __put_user(attr->mq_curmsgs, &uattr->mq_curmsgs);
+}
+
+COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
+		       int, oflag, compat_mode_t, mode,
+		       struct compat_mq_attr __user *, u_attr)
+{
+	void __user *p = NULL;
+	if (u_attr && oflag & O_CREAT) {
+		struct mq_attr attr;
+
+		memset(&attr, 0, sizeof(attr));
+
+		p = compat_alloc_user_space(sizeof(attr));
+		if (get_compat_mq_attr(&attr, u_attr) ||
+		    copy_to_user(p, &attr, sizeof(attr)))
+			return -EFAULT;
+	}
+	return sys_mq_open(u_name, oflag, mode, p);
+}
+
+COMPAT_SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes,
+		       const char __user *, u_msg_ptr,
+		       compat_size_t, msg_len, unsigned int, msg_prio,
+		       const struct compat_timespec __user *, u_abs_timeout)
+{
+	struct timespec __user *u_ts;
+
+	if (compat_convert_timespec(&u_ts, u_abs_timeout))
+		return -EFAULT;
+
+	return sys_mq_timedsend(mqdes, u_msg_ptr, msg_len,
+			msg_prio, u_ts);
+}
+
+COMPAT_SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes,
+		       char __user *, u_msg_ptr,
+		       compat_size_t, msg_len, unsigned int __user *, u_msg_prio,
+		       const struct compat_timespec __user *, u_abs_timeout)
+{
+	struct timespec __user *u_ts;
+
+	if (compat_convert_timespec(&u_ts, u_abs_timeout))
+		return -EFAULT;
+
+	return sys_mq_timedreceive(mqdes, u_msg_ptr, msg_len,
+			u_msg_prio, u_ts);
+}
+
+COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
+		       const struct compat_sigevent __user *, u_notification)
+{
+	struct sigevent __user *p = NULL;
+	if (u_notification) {
+		struct sigevent n;
+		p = compat_alloc_user_space(sizeof(*p));
+		if (get_compat_sigevent(&n, u_notification))
+			return -EFAULT;
+		if (n.sigev_notify == SIGEV_THREAD)
+			n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
+		if (copy_to_user(p, &n, sizeof(*p)))
+			return -EFAULT;
+	}
+	return sys_mq_notify(mqdes, p);
+}
+
+COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
+		       const struct compat_mq_attr __user *, u_mqstat,
+		       struct compat_mq_attr __user *, u_omqstat)
+{
+	struct mq_attr mqstat;
+	struct mq_attr __user *p = compat_alloc_user_space(2 * sizeof(*p));
+	long ret;
+
+	memset(&mqstat, 0, sizeof(mqstat));
+
+	if (u_mqstat) {
+		if (get_compat_mq_attr(&mqstat, u_mqstat) ||
+		    copy_to_user(p, &mqstat, sizeof(mqstat)))
+			return -EFAULT;
+	}
+	ret = sys_mq_getsetattr(mqdes,
+				u_mqstat ? p : NULL,
+				u_omqstat ? p + 1 : NULL);
+	if (ret)
+		return ret;
+	if (u_omqstat) {
+		if (copy_from_user(&mqstat, p + 1, sizeof(mqstat)) ||
+		    put_compat_mq_attr(&mqstat, u_omqstat))
+			return -EFAULT;
+	}
+	return 0;
+}