Technical Reference: Kernel and Subsystems, Volume 1

copyinstr Kernel Service

Purpose

Copies a character string (including the terminating null character) from user to kernel space.

Syntax

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

int copyinstr (from, to, max, actual) caddt_t from; caddt_t to; uint max; uint * actual;

Parameters

from	Specifies the address of the character string to copy.
to	Specifies the address to which the character string is to be copied.
max	Specifies the number of characters to be copied.
actual	Specifies a parameter, passed by reference, that is updated by the copyinstr service with the actual number of characters copied.

Description

The copyinstr kernel service permits a user to copy character data from one location to another. The source location must be in user space or can be in kernel space if the caller is a kernel process. The destination is in kernel space.

Execution Environment

The copyinstr kernel service can be called from the process environment only.

Return Values

0	Indicates a successful operation.
E2BIG	Indicates insufficient space to complete the copy.
EIO	Indicates that a permanent I/O error occurred while referencing data.
ENOSPC	Indicates insufficient file system or paging space.
EFAULT	Indicates that the user has insufficient authority to access the data or the address specified in the uaddr parameter is not valid.

Related Information

Accessing User-Mode Data While in Kernel Mode and Memory Kernel Services in AIX 5L Version 5.2 Kernel Extensions and Device Support Programming Concepts.