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* 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 <>
#include <linux/compat.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/mqueue.h>
#include <linux/syscalls.h>
#include <asm/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);
asmlinkage long compat_sys_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);
static int compat_prepare_timeout(struct timespec __user * *p,
const struct compat_timespec __user *u)
struct timespec ts;
if (!u) {
*p = NULL;
return 0;
*p = compat_alloc_user_space(sizeof(ts));
if (get_compat_timespec(&ts, u) || copy_to_user(*p, &ts, sizeof(ts)))
return -EFAULT;
return 0;
asmlinkage long compat_sys_mq_timedsend(mqd_t mqdes,
const char __user *u_msg_ptr,
size_t msg_len, unsigned int msg_prio,
const struct compat_timespec __user *u_abs_timeout)
struct timespec __user *u_ts;
if (compat_prepare_timeout(&u_ts, u_abs_timeout))
return -EFAULT;
return sys_mq_timedsend(mqdes, u_msg_ptr, msg_len,
msg_prio, u_ts);
asmlinkage ssize_t compat_sys_mq_timedreceive(mqd_t mqdes,
char __user *u_msg_ptr,
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_prepare_timeout(&u_ts, u_abs_timeout))
return -EFAULT;
return sys_mq_timedreceive(mqdes, u_msg_ptr, msg_len,
u_msg_prio, u_ts);
asmlinkage long compat_sys_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);
asmlinkage long compat_sys_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;