ipc/compat_mq.c

   1 /*
   2  *  ipc/compat_mq.c
   3  *    32 bit emulation for POSIX message queue system calls
   4  *
   5  *    Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author: Arnd Bergmann <arnd@arndb.de>
   7  */
   8
   9 #include <linux/compat.h>
  10 #include <linux/fs.h>
  11 #include <linux/kernel.h>
  12 #include <linux/mqueue.h>
  13 #include <linux/syscalls.h>
  14
  15 #include <asm/uaccess.h>
  16
  17 struct compat_mq_attr {
  18         compat_long_t mq_flags;      /* message queue flags                  */
  19         compat_long_t mq_maxmsg;     /* maximum number of messages           */
  20         compat_long_t mq_msgsize;    /* maximum message size                 */
  21         compat_long_t mq_curmsgs;    /* number of messages currently queued  */
  22         compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
  23 };
  24
  25 static inline int get_compat_mq_attr(struct mq_attr *attr,
  26                         const struct compat_mq_attr __user *uattr)
  27 {
  28         if (!access_ok(VERIFY_READ, uattr, sizeof *uattr))
  29                 return -EFAULT;
  30
  31         return __get_user(attr->mq_flags, &uattr->mq_flags)
  32                 | __get_user(attr->mq_maxmsg, &uattr->mq_maxmsg)
  33                 | __get_user(attr->mq_msgsize, &uattr->mq_msgsize)
  34                 | __get_user(attr->mq_curmsgs, &uattr->mq_curmsgs);
  35 }
  36
  37 static inline int put_compat_mq_attr(const struct mq_attr *attr,
  38                         struct compat_mq_attr __user *uattr)
  39 {
  40         if (clear_user(uattr, sizeof *uattr))
  41                 return -EFAULT;
  42
  43         return __put_user(attr->mq_flags, &uattr->mq_flags)
  44                 | __put_user(attr->mq_maxmsg, &uattr->mq_maxmsg)
  45                 | __put_user(attr->mq_msgsize, &uattr->mq_msgsize)
  46                 | __put_user(attr->mq_curmsgs, &uattr->mq_curmsgs);
  47 }
  48
  49 asmlinkage long compat_sys_mq_open(const char __user *u_name,
  50                         int oflag, compat_mode_t mode,
  51                         struct compat_mq_attr __user *u_attr)
  52 {
  53         void __user *p = NULL;
  54         if (u_attr && oflag & O_CREAT) {
  55                 struct mq_attr attr;
  56
  57                 memset(&attr, 0, sizeof(attr));
  58
  59                 p = compat_alloc_user_space(sizeof(attr));
  60                 if (get_compat_mq_attr(&attr, u_attr) ||
  61                     copy_to_user(p, &attr, sizeof(attr)))
  62                         return -EFAULT;
  63         }
  64         return sys_mq_open(u_name, oflag, mode, p);
  65 }
  66
  67 static int compat_prepare_timeout(struct timespec __user **p,
  68                                   const struct compat_timespec __user *u)
  69 {
  70         struct timespec ts;
  71         if (!u) {
  72                 *p = NULL;
  73                 return 0;
  74         }
  75         *p = compat_alloc_user_space(sizeof(ts));
  76         if (get_compat_timespec(&ts, u) || copy_to_user(*p, &ts, sizeof(ts)))
  77                 return -EFAULT;
  78         return 0;
  79 }
  80
  81 asmlinkage long compat_sys_mq_timedsend(mqd_t mqdes,
  82                         const char __user *u_msg_ptr,
  83                         size_t msg_len, unsigned int msg_prio,
  84                         const struct compat_timespec __user *u_abs_timeout)
  85 {
  86         struct timespec __user *u_ts;
  87
  88         if (compat_prepare_timeout(&u_ts, u_abs_timeout))
  89                 return -EFAULT;
  90
  91         return sys_mq_timedsend(mqdes, u_msg_ptr, msg_len,
  92                         msg_prio, u_ts);
  93 }
  94
  95 asmlinkage ssize_t compat_sys_mq_timedreceive(mqd_t mqdes,
  96                         char __user *u_msg_ptr,
  97                         size_t msg_len, unsigned int __user *u_msg_prio,
  98                         const struct compat_timespec __user *u_abs_timeout)
  99 {
 100         struct timespec __user *u_ts;
 101         if (compat_prepare_timeout(&u_ts, u_abs_timeout))
 102                 return -EFAULT;
 103
 104         return sys_mq_timedreceive(mqdes, u_msg_ptr, msg_len,
 105                         u_msg_prio, u_ts);
 106 }
 107
 108 asmlinkage long compat_sys_mq_notify(mqd_t mqdes,
 109                         const struct compat_sigevent __user *u_notification)
 110 {
 111         struct sigevent __user *p = NULL;
 112         if (u_notification) {
 113                 struct sigevent n;
 114                 p = compat_alloc_user_space(sizeof(*p));
 115                 if (get_compat_sigevent(&n, u_notification))
 116                         return -EFAULT;
 117                 if (n.sigev_notify == SIGEV_THREAD)
 118                         n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
 119                 if (copy_to_user(p, &n, sizeof(*p)))
 120                         return -EFAULT;
 121         }
 122         return sys_mq_notify(mqdes, p);
 123 }
 124
 125 asmlinkage long compat_sys_mq_getsetattr(mqd_t mqdes,
 126                         const struct compat_mq_attr __user *u_mqstat,
 127                         struct compat_mq_attr __user *u_omqstat)
 128 {
 129         struct mq_attr mqstat;
 130         struct mq_attr __user *p = compat_alloc_user_space(2 * sizeof(*p));
 131         long ret;
 132
 133         memset(&mqstat, 0, sizeof(mqstat));
 134
 135         if (u_mqstat) {
 136                 if (get_compat_mq_attr(&mqstat, u_mqstat) ||
 137                     copy_to_user(p, &mqstat, sizeof(mqstat)))
 138                         return -EFAULT;
 139         }
 140         ret = sys_mq_getsetattr(mqdes,
 141                                 u_mqstat ? p : NULL,
 142                                 u_omqstat ? p + 1 : NULL);
 143         if (ret)
 144                 return ret;
 145         if (u_omqstat) {
 146                 if (copy_from_user(&mqstat, p + 1, sizeof(mqstat)) ||
 147                     put_compat_mq_attr(&mqstat, u_omqstat))
 148                         return -EFAULT;
 149         }
 150         return 0;
 151 }