table of contents
FETCH(9) | Kernel Developer's Manual | FETCH(9) |
NAME¶
fetch
, fubyte
,
fuswintr
, fuword
,
fuword16
, fuword32
,
fuword64
, fueword
,
fueword32
, fueword64
—
SYNOPSIS¶
#include <sys/types.h>
#include <sys/systm.h>
int
fubyte
(volatile
const void *base);
long
fuword
(volatile
const void *base);
int
fuword16
(volatile
const void *base);
int32_t
fuword32
(volatile
const void *base);
int64_t
fuword64
(volatile
const void *base);
long
fueword
(volatile
const void *base, long
*val);
int32_t
fueword32
(volatile
const void *base, int32_t
*val);
int64_t
fueword64
(volatile
const void *base, int64_t
*val);
#include
<sys/resourcevar.h>
int
fuswintr
(void
*base);
DESCRIPTION¶
Thefetch
functions are designed to copy small amounts
of data from user-space of the current process. If read is successful, it is
performed atomically. The data read must be naturally aligned.
The fetch
routines provide the following
functionality:
fubyte
()- Fetches a byte of data from the user-space address base. The byte read is zero-extended into the results variable.
fuword
()- Fetches a word of data (long) from the user-space address base.
fuword16
()- Fetches 16 bits of data from the user-space address base. The half-word read is zero-extended into the results variable.
fuword32
()- Fetches 32 bits of data from the user-space address base.
fuword64
()- Fetches 64 bits of data from the user-space address base.
fuswintr
()- Fetches a short word of data from the user-space address base. This function is safe to call during an interrupt context.
fueword
()- Fetches a word of data (long) from the user-space address base and stores the result in the variable pointed by val.
fueword32
()- Fetches 32 bits of data from the user-space address base and stores the result in the variable pointed by val.
fueword64
()- Fetches 64 bits of data from the user-space address base and stores the result in the variable pointed by val.
The callers of fuword
(),
fuword32
() and fuword64
()
functions cannot distinguish between -1 read from userspace and function
failure.
RETURN VALUES¶
Thefubyte
(), fuword
(),
fuword16
(), fuword32
(),
fuword64
(), and fuswintr
()
functions return the data fetched or -1 on failure. The
fueword
(), fueword32
() and
fueword64
() functions return 0 on success and -1 on
failure.
SEE ALSO¶
copy(9), store(9)October 29, 2014 | Linux 4.9.0-9-amd64 |