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                 p = compat_alloc_user_space(sizeof(attr));
  57                 if (get_compat_mq_attr(&attr, u_attr) ||
  58                     copy_to_user(p, &attr, sizeof(attr)))
  59                         return -EFAULT;
  60         }
  61         return sys_mq_open(u_name, oflag, mode, p);
  62 }
  63
  64 static int compat_prepare_timeout(struct timespec __user * *p,
  65                                   const struct compat_timespec __user *u)
  66 {
  67         struct timespec ts;
  68         if (!u) {
  69                 *p = NULL;
  70                 return 0;
  71         }
  72         *p = compat_alloc_user_space(sizeof(ts));
  73         if (get_compat_timespec(&ts, u) || copy_to_user(*p, &ts, sizeof(ts)))
  74                 return -EFAULT;
  75         return 0;
  76 }
  77
  78 asmlinkage long compat_sys_mq_timedsend(mqd_t mqdes,
  79                         const char __user *u_msg_ptr,
  80                         size_t msg_len, unsigned int msg_prio,
  81                         const struct compat_timespec __user *u_abs_timeout)
  82 {
  83         struct timespec __user *u_ts;
  84
  85         if (compat_prepare_timeout(&u_ts, u_abs_timeout))
  86                 return -EFAULT;
  87
  88         return sys_mq_timedsend(mqdes, u_msg_ptr, msg_len,
  89                         msg_prio, u_ts);
  90 }
  91
  92 asmlinkage ssize_t compat_sys_mq_timedreceive(mqd_t mqdes,
  93                         char __user *u_msg_ptr,
  94                         size_t msg_len, unsigned int __user *u_msg_prio,
  95                         const struct compat_timespec __user *u_abs_timeout)
  96 {
  97         struct timespec __user *u_ts;
  98         if (compat_prepare_timeout(&u_ts, u_abs_timeout))
  99                 return -EFAULT;
 100
 101         return sys_mq_timedreceive(mqdes, u_msg_ptr, msg_len,
 102                         u_msg_prio, u_ts);
 103 }
 104
 105 asmlinkage long compat_sys_mq_notify(mqd_t mqdes,
 106                         const struct compat_sigevent __user *u_notification)
 107 {
 108         struct sigevent __user *p = NULL;
 109         if (u_notification) {
 110                 struct sigevent n;
 111                 p = compat_alloc_user_space(sizeof(*p));
 112                 if (get_compat_sigevent(&n, u_notification))
 113                         return -EFAULT;
 114                 if (n.sigev_notify == SIGEV_THREAD)
 115                         n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
 116                 if (copy_to_user(p, &n, sizeof(*p)))
 117                         return -EFAULT;
 118         }
 119         return sys_mq_notify(mqdes, p);
 120 }
 121
 122 asmlinkage long compat_sys_mq_getsetattr(mqd_t mqdes,
 123                         const struct compat_mq_attr __user *u_mqstat,
 124                         struct compat_mq_attr __user *u_omqstat)
 125 {
 126         struct mq_attr mqstat;
 127         struct mq_attr __user *p = compat_alloc_user_space(2 * sizeof(*p));
 128         long ret;
 129
 130         if (u_mqstat) {
 131                 if (get_compat_mq_attr(&mqstat, u_mqstat) ||
 132                     copy_to_user(p, &mqstat, sizeof(mqstat)))
 133                         return -EFAULT;
 134         }
 135         ret = sys_mq_getsetattr(mqdes,
 136                                 u_mqstat ? p : NULL,
 137                                 u_omqstat ? p + 1 : NULL);
 138         if (ret)
 139                 return ret;
 140         if (u_omqstat) {
 141                 if (copy_from_user(&mqstat, p + 1, sizeof(mqstat)) ||
 142                     put_compat_mq_attr(&mqstat, u_omqstat))
 143                         return -EFAULT;
 144         }
 145         return 0;
 146 }