compat_mq.c

Go to the documentation of this file.

/*
 *  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 <[email protected]>
 */

#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;
}