xref: /freebsd/lib/libc/gen/cap_rights_get.3 (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
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28.Dd May 5, 2020
29.Dt CAP_RIGHTS_GET 3
30.Os
31.Sh NAME
32.Nm cap_rights_get
33.Nd obtain capability rights
34.Sh LIBRARY
35.Lb libc
36.Sh SYNOPSIS
37.In sys/capsicum.h
38.Ft int
39.Fn cap_rights_get "int fd" "cap_rights_t *rights"
40.Sh DESCRIPTION
41The
42.Nm cap_rights_get
43function allows to obtain current capability rights for the given descriptor.
44The function will fill the
45.Fa rights
46argument with all capability rights if they were not limited or capability
47rights configured during the last successful call of
48.Xr cap_rights_limit 2
49on the given descriptor.
50.Pp
51The
52.Fa rights
53argument can be inspected using
54.Xr cap_rights_init 3
55family of functions.
56.Pp
57The complete list of the capability rights can be found in the
58.Xr rights 4
59manual page.
60.Sh RETURN VALUES
61.Rv -std
62.Sh EXAMPLES
63The following example demonstrates how to limit file descriptor capability
64rights and how to obtain them.
65.Bd -literal
66cap_rights_t setrights, getrights;
67int fd;
68
69memset(&setrights, 0, sizeof(setrights));
70memset(&getrights, 0, sizeof(getrights));
71
72fd = open("/tmp/foo", O_RDONLY);
73if (fd < 0)
74	err(1, "open() failed");
75
76cap_rights_init(&setrights, CAP_FSTAT, CAP_READ);
77if (cap_rights_limit(fd, &setrights) < 0 && errno != ENOSYS)
78	err(1, "cap_rights_limit() failed");
79
80if (cap_rights_get(fd, &getrights) < 0 && errno != ENOSYS)
81	err(1, "cap_rights_get() failed");
82
83assert(memcmp(&setrights, &getrights, sizeof(setrights)) == 0);
84.Ed
85.Sh ERRORS
86.Fn cap_rights_get
87succeeds unless:
88.Bl -tag -width Er
89.It Bq Er EBADF
90The
91.Fa fd
92argument is not a valid active descriptor.
93.It Bq Er EFAULT
94The
95.Fa rights
96argument points at an invalid address.
97.El
98.Sh SEE ALSO
99.Xr cap_rights_limit 2 ,
100.Xr errno 2 ,
101.Xr open 2 ,
102.Xr assert 3 ,
103.Xr cap_rights_init 3 ,
104.Xr err 3 ,
105.Xr memcmp 3 ,
106.Xr memset 3 ,
107.Xr capsicum 4 ,
108.Xr rights 4
109.Sh HISTORY
110The
111.Fn cap_rights_get
112function first appeared in
113.Fx 9.2 .
114Support for capabilities and capabilities mode was developed as part of the
115.Tn TrustedBSD
116Project.
117.Sh AUTHORS
118This function was created by
119.An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net
120under sponsorship of the FreeBSD Foundation.
121