strncpy_from_user(9) [suse man page]

STRNCPY_FROM_USER(9)					    Memory Management in Linux					      STRNCPY_FROM_USER(9)

NAME

       strncpy_from_user - Copy a NUL terminated string from userspace.

SYNOPSIS

       long strncpy_from_user(char * dst, const char __user * src, long count);

ARGUMENTS

       dst
	   Destination address, in kernel space. This buffer must be at least count bytes long.

       src
	   Source address, in user space.

       count
	   Maximum number of bytes to copy, including the trailing NUL.

DESCRIPTION

       Copies a NUL-terminated string from userspace to kernel space.

       On success, returns the length of the string (not including the trailing NUL).

       If access to userspace fails, returns -EFAULT (some data may have been copied).

       If count is smaller than the length of the string, copies count bytes and returns count.

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010						      STRNCPY_FROM_USER(9)

COPY(9) 						   BSD Kernel Developer's Manual						   COPY(9)

NAME

     copy, copyin, copyout, copystr, copyinstr, copyoutstr -- kernel space to/from user space copy functions

SYNOPSIS

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

     int
     copyin(const void *uaddr, void *kaddr, size_t len);

     int
     copyout(const void *kaddr, void *uaddr, size_t len);

     int
     copystr(const void *kfaddr, void *kdaddr, size_t len, size_t *done);

     int
     copyinstr(const void *uaddr, void *kaddr, size_t len, size_t *done);

     int
     copyoutstr(const void *kaddr, void *uaddr, size_t len, size_t *done);

     int
     copyin_proc(struct proc *p, const void *uaddr, void *kaddr, size_t len);

     int
     copyout_proc(struct proc *p, const void *kaddr, void *uaddr, size_t len);

     int
     ioctl_copyin(int ioctlflags, const void *src, void *dst, size_t len);

     int
     ioctl_copyout(int ioctlflags, const void *src, void *dst, size_t len);

DESCRIPTION

     The copy functions are designed to copy contiguous data from one address to another.  All but copystr() copy data from user-space to kernel-
     space or vice-versa.

     The copy routines provide the following functionality:

     copyin()	     Copies len bytes of data from the user-space address uaddr in the current process to the kernel-space address kaddr.

     copyout()	     Copies len bytes of data from the kernel-space address kaddr to the user-space address uaddr in the current process.

     copystr()	     Copies a NUL-terminated string, at most len bytes long, from kernel-space address kfaddr to kernel-space address kdaddr.  If
		     the done argument is non-NULL, the number of bytes actually copied, including the terminating NUL, is returned in *done.

     copyinstr()     Copies a NUL-terminated string, at most len bytes long, from user-space address uaddr in the current process to kernel-space
		     address kaddr.  If the done argument is non-NULL, the number of bytes actually copied, including the terminating NUL, is
		     returned in *done.

     copyoutstr()    Copies a NUL-terminated string, at most len bytes long, from kernel-space address kaddr to user-space address uaddr in the
		     current process.  If the done argument is non-NULL, the number of bytes actually copied, including the terminating NUL, is
		     returned in *done.

     copyin_proc()   Like copyin(), except it operates on the address space of the process p.

     copyout_proc()  Like copyout(), except it operates on the address space of the process p.

     ioctl_copyin()  Like copyin(), except it operates on kernel adresses when the FKIOCTL flag is passed in ioctlflags from the ioctl call.

     ioctl_copyout()
		     Like copyout(), except it operates on kernel adresses when the FKIOCTL flag is passed in ioctlflags from the ioctl call.

RETURN VALUES

     The copy functions return 0 on success or EFAULT if a bad address is encountered.	In addition, the copystr(), copyinstr(), and copyoutstr()
     functions return ENAMETOOLONG if the string is longer than len bytes.

SEE ALSO

     fetch(9), store(9)

BSD
								  August 28, 2005							       BSD