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Name

Synopsis

#include <sys/types.h>
#include <sys/ddi.h>

int copyin(caddr_t userbuf, caddr_t driverbuf, size_t cn);

Interface Level

Architecture independent level 1 (DDI/DKI).

Arguments

userbuf

User program source address from which data is transferred.

driverbuf

Driver destination address to which data is transferred.

cn

Number of bytes transferred.

Description

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

Return Values

• paging fault; the driver tried to access a page of memory for which it did not have read or write access
• invalid user address, such as a user area or stack area

invalid address that would have resulted in data being copied into the user block

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

Context

copyin() can be called from user context only.

Examples

A driver ioctl(9E) routine (line 9) can be used to get or set device attributes or registers. In the XX_GETREGS condition (line 17), the driver copies the current device register values to a user data area (line 18). 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  }; /* end device */
 7
 8  extern struct device xx_addr[]; /* phys. device regs. location */
      . . .
 9  xx_ioctl(dev, cmd, arg, mode, cred_p, rval_p)
10          dev_t   dev;
11          int     cmd, arg;
12               ...
13  {
14      register struct device *rp = &xx_addr[getminor(dev) >> 4];
15      switch (cmd)  {
16
17       case XX_SETREGS:     /* copy device regs. to user program */
18            if (copyin((caddr_t)arg, (caddr_t)rp, sizeof(struct device)))
19                return(EFAULT);
21            break;

See Also

Notes

Driver writers who intend to support layered ioctls in their ioctl(9E) routines should use ddi_copyin(9F) instead.

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

Table of Contents

• Name
• Synopsis
• Interface Level
• Arguments
• Description
• Return Values
• Context
• Examples
• See Also
• Notes