Manual Pages for UNIX Operating System command usage for man ddi_copyout

Kernel Functions for Drivers                      ddi_copyout(9F)



NAME
     ddi_copyout - copy data from a driver

SYNOPSIS
     #include 
     #include 
     #include 



     int ddi_copyout(const void *driverbuf, void *buf, size_t cn, int flags);


INTERFACE LEVEL
     Solaris DDI specific (Solaris DDI).

PARAMETERS
     driverbuf    Source address in the  driver  from  which  the
                  data is transferred.


     buf          Destination  address  to  which  the  data   is
                  transferred.


     cn           Number of bytes to copy.


     flags        Set of flag bits  that  provide  address  space
                  information about buf.


DESCRIPTION
     This routine is designed for use in  driver  ioctl(9E)  rou-
     tines for drivers that support layered ioctls. ddi_copyout()
     copies data from a driver buffer to a  destination  address,
     buf.


     The flags argument determines the address space  information
     about  buf.  If the FKIOCTL flag is set, this indicates that
     buf is a kernel address,  and   ddi_copyout()  behaves  like
     bcopy(9F).  Otherwise,   buf is interpreted as a user buffer
     address, and ddi_copyout() behaves like copyout(9F).


     Addresses that are word-aligned are moved most  efficiently.
     However,  the  driver  developer  is  not  obliged to ensure
     alignment.  This function automatically finds the most effi-
     cient move algorithm according to address alignment.





SunOS 5.11          Last change: 19 Apr 2000                    1






Kernel Functions for Drivers                      ddi_copyout(9F)



RETURN VALUES
     Under normal conditions, 0 is returned to  indicate  a  suc-
     cessful  copy.  Otherwise, -1 is returned if one of the fol-
     lowing occurs:

         o    Paging fault; the driver tried to access a page  of
              memory  for  which  it  did  not have read or write
              access.

         o    Invalid user address, such as a user area or  stack
              area.

         o    Invalid address that would have  resulted  in  data
              being copied into the user block.

         o    Hardware fault; a hardware error  prevented  access
              to  the  specified  user  memory.  For  example, an
              uncorrectable parity or ECC error occurred.


     If -1 is returned to the caller, driver entry point routines
     should return EFAULT.

CONTEXT
     ddi_copyout() can be called  from  user  or  kernel  context
     only.

EXAMPLES
     Example 1 ddi_copyout() example


     A driver ioctl(9E) routine (line 12) can be used to  get  or
     set device attributes or registers. In the XX_GETREGS condi-
     tion (line 25), the driver copies the current device  regis-
     ter  values to another data area.  If the specified argument
     contains an invalid address, an error code is returned.


       1  struct device  {        /* layout of physical device registers  */
        2     int      control;    /* physical device control word  */
        3     int      status;     /* physical device status word   */
        4     short    recv_char;  /* receive character from device */
        5     short    xmit_char;  /* transmit character to device  */
        6  };

        7  struct device_state {
        8     volatile struct device *regsp;   /* pointer to device registers */
        9     kmutex_t reg_mutex;              /* protect device registers */
              . . .
       10  };

       11  static void *statep; /* for soft state routines */



SunOS 5.11          Last change: 19 Apr 2000                    2






Kernel Functions for Drivers                      ddi_copyout(9F)




       12  xxioctl(dev_t dev, int cmd, int arg, int mode,
       13      cred_t *cred_p, int *rval_p)
       14  {
       15      struct device_state *sp;
       16      volatile struct device *rp;
       17      struct device reg_buf;     /* temporary buffer for registers */
       18      int instance;

       19      instance = getminor(dev);
       20      sp = ddi_get_soft_state(statep, instance);
       21      if (sp == NULL)
       22          return (ENXIO);
       23      rp = sp->regsp;
               . . .
       24      switch (cmd)  {

       25      case XX_GETREGS:   /* copy registers to arg */
       26            mutex_enter(&sp->reg_mutex);
       27            /*
       28             * Copy data from device registers to
       29             * temporary device register buffer
       30             * e.g. reg_buf.control = rp->control;
       31             */
       32            mutex_exit(&sp->reg_mutex);
       33            if (ddi_copyout(®_buf, arg,
       34                sizeof (struct device), mode) != 0) {
       35                    return (EFAULT);
       36            }

       37            break;
       38      }
       39  }


SEE ALSO
     ioctl(9E),     bcopy(9F),      copyin(9F),      copyout(9F),
     ddi_copyin(9F), uiomove(9F)


     Writing Device Drivers

NOTES
     The value of the flags argument to ddi_copyout()  should  be
     passed  through  directly  from the mode argument of ioctl()
     untranslated.


     Driver defined locks should not be held across calls to this
     function.





SunOS 5.11          Last change: 19 Apr 2000                    3






Kernel Functions for Drivers                      ddi_copyout(9F)



     ddi_copyout() should not be used from a streams driver.  See
     M_COPYIN and M_COPYOUT in STREAMS Programming Guide.





















































SunOS 5.11          Last change: 19 Apr 2000                    4