xref: /freebsd/lib/libc/gen/cap_rights_get.3 (revision a7623790fb345e6dc986dfd31df0ace115e6f2e4)
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31.Dd May 5, 2020
32.Dt CAP_RIGHTS_GET 3
33.Os
34.Sh NAME
35.Nm cap_rights_get
36.Nd obtain capability rights
37.Sh LIBRARY
38.Lb libc
39.Sh SYNOPSIS
40.In sys/capsicum.h
41.Ft int
42.Fn cap_rights_get "int fd" "cap_rights_t *rights"
43.Sh DESCRIPTION
44The
45.Nm cap_rights_get
46function allows to obtain current capability rights for the given descriptor.
47The function will fill the
48.Fa rights
49argument with all capability rights if they were not limited or capability
50rights configured during the last successful call of
51.Xr cap_rights_limit 2
52on the given descriptor.
53.Pp
54The
55.Fa rights
56argument can be inspected using
57.Xr cap_rights_init 3
58family of functions.
59.Pp
60The complete list of the capability rights can be found in the
61.Xr rights 4
62manual page.
63.Sh RETURN VALUES
64.Rv -std
65.Sh EXAMPLES
66The following example demonstrates how to limit file descriptor capability
67rights and how to obtain them.
68.Bd -literal
69cap_rights_t setrights, getrights;
70int fd;
71
72memset(&setrights, 0, sizeof(setrights));
73memset(&getrights, 0, sizeof(getrights));
74
75fd = open("/tmp/foo", O_RDONLY);
76if (fd < 0)
77	err(1, "open() failed");
78
79cap_rights_init(&setrights, CAP_FSTAT, CAP_READ);
80if (cap_rights_limit(fd, &setrights) < 0 && errno != ENOSYS)
81	err(1, "cap_rights_limit() failed");
82
83if (cap_rights_get(fd, &getrights) < 0 && errno != ENOSYS)
84	err(1, "cap_rights_get() failed");
85
86assert(memcmp(&setrights, &getrights, sizeof(setrights)) == 0);
87.Ed
88.Sh ERRORS
89.Fn cap_rights_get
90succeeds unless:
91.Bl -tag -width Er
92.It Bq Er EBADF
93The
94.Fa fd
95argument is not a valid active descriptor.
96.It Bq Er EFAULT
97The
98.Fa rights
99argument points at an invalid address.
100.El
101.Sh SEE ALSO
102.Xr cap_rights_limit 2 ,
103.Xr errno 2 ,
104.Xr open 2 ,
105.Xr assert 3 ,
106.Xr cap_rights_init 3 ,
107.Xr err 3 ,
108.Xr memcmp 3 ,
109.Xr memset 3 ,
110.Xr capsicum 4 ,
111.Xr rights 4
112.Sh HISTORY
113The
114.Fn cap_rights_get
115function first appeared in
116.Fx 9.2 .
117Support for capabilities and capabilities mode was developed as part of the
118.Tn TrustedBSD
119Project.
120.Sh AUTHORS
121This function was created by
122.An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net
123under sponsorship of the FreeBSD Foundation.
124