int
fsetown(
struct lwp *l
, pid_t *pgid
, int cmd
, const void *data
)
int
fgetown(
struct lwp *l
, pid_t pgid
, int cmd
, void *data
)
void
fownsignal(
pid_t pgid
, int signo
, int code
, int band
, void *fdescdata
)
fsetown()
sets the owner of file.
cmd
is an ioctl command, one of
SIOCSPGRP
,
FIOSETOWN
,
and
TIOCSPGRP
.
data
is interpreted as a pointer to a signed integer, the integer being
the ID of the owner.
The
cmd
determines how exactly
data
should be interpreted.
If
cmd
is
TIOCSPGRP
,
the ID needs to be positive and is interpreted as process group ID.
For
SIOCSPGRP
and
FIOSETOWN
,
the passed ID is the process ID if positive, or the process group ID
if negative.
fgetown()
returns the current owner of the file.
cmd
is an ioctl command, one of
SIOCGPGRP
,
FIOGETOWN
,
and
TIOCGPGRP
.
data
is interpreted as a pointer to a signed integer,
and the value is set according to the passed
cmd
.
For
TIOCGPGRP
,
the returned
data
value is positive process group ID if the owner is the process group,
or negative process ID if the owner is a process.
For other ioctls,
the returned value is the positive process ID if the owner is a process,
or the negative process group ID if the owner is a process group.
fownsignal()
schedules the
signo
signal to be sent to the current file descriptor owner.
The signals typically used with this function are
SIGIO
and
SIGURG
.
The
code
and
band
arguments are sent along with the signal as additional signal specific
information if
SA_SIGINFO
is activated.
If the information is not available from the context of the
fownsignal()
call, these should be passed as zero.
fdescdata
is used to lookup the file descriptor for
SA_SIGINFO
signals.
If it is specified, the file descriptor number is sent along with
the signal as additional signal specific information.
If file descriptor data pointer is not available in the context of the
fownsignal()
call,
NULL
should be used instead.
Note that a
fcntl(2)
F_SETOWN
request
is translated by the kernel to a
FIOSETOWN
ioctl, and
F_GETOWN
is translated to
FIOGETOWN
.
This is done transparently by generic code, before the device- or
subsystem-specific ioctl entry function is called.