xref: /freebsd/lib/libc/gen/cap_rights_get.3 (revision fa9896e082a1046ff4fbc75fcba4d18d1f2efc19)

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.Dd May 5, 2020
.Dt CAP_RIGHTS_GET 3
.Os
.Sh NAME
.Nm cap_rights_get
.Nd obtain capability rights
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/capsicum.h
.Ft int
.Fn cap_rights_get "int fd" "cap_rights_t *rights"
.Sh DESCRIPTION
The
.Nm cap_rights_get
function allows to obtain current capability rights for the given descriptor.
The function will fill the
.Fa rights
argument with all capability rights if they were not limited or capability
rights configured during the last successful call of
.Xr cap_rights_limit 2
on the given descriptor.
.Pp
The
.Fa rights
argument can be inspected using
.Xr cap_rights_init 3
family of functions.
.Pp
The complete list of the capability rights can be found in the
.Xr rights 4
manual page.
.Sh RETURN VALUES
.Rv -std
.Sh EXAMPLES
The following example demonstrates how to limit file descriptor capability
rights and how to obtain them.
.Bd -literal
cap_rights_t setrights, getrights;
int fd;

memset(&setrights, 0, sizeof(setrights));
memset(&getrights, 0, sizeof(getrights));

fd = open("/tmp/foo", O_RDONLY);
if (fd < 0)
	err(1, "open() failed");

cap_rights_init(&setrights, CAP_FSTAT, CAP_READ);
if (cap_rights_limit(fd, &setrights) < 0 && errno != ENOSYS)
	err(1, "cap_rights_limit() failed");

if (cap_rights_get(fd, &getrights) < 0 && errno != ENOSYS)
	err(1, "cap_rights_get() failed");

assert(memcmp(&setrights, &getrights, sizeof(setrights)) == 0);
.Ed
.Sh ERRORS
.Fn cap_rights_get
succeeds unless:
.Bl -tag -width Er
.It Bq Er EBADF
The
.Fa fd
argument is not a valid active descriptor.
.It Bq Er EFAULT
The
.Fa rights
argument points at an invalid address.
.El
.Sh SEE ALSO
.Xr cap_rights_limit 2 ,
.Xr errno 2 ,
.Xr open 2 ,
.Xr assert 3 ,
.Xr cap_rights_init 3 ,
.Xr err 3 ,
.Xr memcmp 3 ,
.Xr memset 3 ,
.Xr capsicum 4 ,
.Xr rights 4
.Sh HISTORY
The
.Fn cap_rights_get
function first appeared in
.Fx 9.2 .
Support for capabilities and capabilities mode was developed as part of the
.Tn TrustedBSD
Project.
.Sh AUTHORS
This function was created by
.An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net
under sponsorship of the FreeBSD Foundation.