xref: /freebsd/lib/libc/posix1e/mac_get.3 (revision b653faaa19c47a4a7e488e5ead738b7ae44ffe8b)

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.Dd September 21, 2023
.Dt MAC_GET 3
.Os
.Sh NAME
.Nm mac_get_file ,
.Nm mac_get_link ,
.Nm mac_get_fd ,
.Nm mac_get_peer ,
.Nm mac_get_pid ,
.Nm mac_get_proc
.Nd get the label of a file, socket, socket peer or process
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/mac.h
.Ft int
.Fn mac_get_file "const char *path" "mac_t label"
.Ft int
.Fn mac_get_link "const char *path" "mac_t label"
.Ft int
.Fn mac_get_fd "int fd" "mac_t label"
.Ft int
.Fn mac_get_peer "int fd" "mac_t label"
.Ft int
.Fn mac_get_pid "pid_t pid" "mac_t label"
.Ft int
.Fn mac_get_proc "mac_t label"
.Sh DESCRIPTION
The
.Fn mac_get_file
system call returns the label associated with a file specified by
pathname.
The
.Fn mac_get_link
function is the same as
.Fn mac_get_file ,
except that it does not follow symlinks.
.Pp
The
.Fn mac_get_fd
system call returns the label associated with an object referenced by
the specified file descriptor.
Note that in the case of a file system socket, the label returned will
be the socket label, which may be different from the label of the
on-disk node acting as a rendezvous for the socket.
The
.Fn mac_get_peer
system call returns the label associated with the remote endpoint of
a socket; the exact semantics of this call will depend on the protocol
domain, communications type, and endpoint; typically this label will
be cached when a connection-oriented protocol instance is first set up,
and is undefined for datagram protocols.
.Pp
The
.Fn mac_get_pid
and
.Fn mac_get_proc
system calls return the process label associated with an arbitrary
process ID, or the current process.
.Pp
Label storage for use with these calls must first be allocated and
prepared using the
.Xr mac_prepare 3
functions.
When an application is done using a label, the memory may be returned
using
.Xr mac_free 3 .
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er EACCES
A component of
.Fa path
is not searchable,
or MAC read access to the file
is denied.
.It Bq Er EINVAL
The requested label operation is not valid for the object referenced by
.Fa fd .
.It Bq Er ENAMETOOLONG
The pathname pointed to by
.Fa path
exceeds
.Dv PATH_MAX ,
or a component of the pathname exceeds
.Dv NAME_MAX .
.It Bq Er ENOENT
A component of
.Fa path
does not exist.
.It Bq Er ENOMEM
Insufficient memory is available
to allocate a new MAC label structure.
.It Bq Er ENOTDIR
A component of
.Fa path
is not a directory.
.El
.Sh SEE ALSO
.Xr mac 3 ,
.Xr mac_free 3 ,
.Xr mac_prepare 3 ,
.Xr mac_set 3 ,
.Xr mac_text 3 ,
.Xr posix1e 3 ,
.Xr mac 4 ,
.Xr mac 9
.Sh STANDARDS
POSIX.1e is described in IEEE POSIX.1e draft 17.
.Sh HISTORY
Support for Mandatory Access Control was introduced in
.Fx 5.0
as part of the
.Tn TrustedBSD
Project.