1.\" Copyright (c) 2020 Ryan Moeller <freqlabs@FreeBSD.org>
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24.Dd December 6, 2023
25.Dt CAP_NETDB 3
26.Os
27.Sh NAME
28.Nm cap_getprotobyname ,
29.Nd "library for getting network proto entry in capability mode"
30.Sh LIBRARY
31.Lb libcap_netdb
32.Sh SYNOPSIS
33.In sys/nv.h
34.In libcasper.h
35.In casper/cap_netdb.h
36.Ft "struct protoent *"
37.Fn cap_getprotobyname "const cap_channel_t *chan" "const char *name"
38.Sh DESCRIPTION
39The function
40.Fn cap_getprotobyname
41is equivalent to
42.Xr getprotobyname 3
43except that the connection to the
44.Nm system.netdb
45service needs to be provided.
46It is reentrant but not thread-safe.
47That is, it may be called from separate threads only with different
48.Vt cap_channel_t
49arguments or with synchronization.
50.Sh EXAMPLES
51The following example first opens a capability to casper and then uses this
52capability to create the
53.Nm system.netdb
54casper service and uses it to look up a protocol by name.
55.Bd -literal
56cap_channel_t *capcas, *capnetdb;
57struct protoent *ent;
58
59/* Open capability to Casper. */
60capcas = cap_init();
61if (capcas == NULL)
62	err(1, "Unable to contact Casper");
63
64/* Enter capability mode sandbox. */
65if (caph_enter() < 0)
66	err(1, "Unable to enter capability mode");
67
68/* Use Casper capability to create capability to the system.netdb service. */
69capnetdb = cap_service_open(capcas, "system.netdb");
70if (capnetdb == NULL)
71	err(1, "Unable to open system.netdb service");
72
73/* Close Casper capability, we don't need it anymore. */
74cap_close(capcas);
75
76ent = cap_getprotobyname(capnetdb, "http");
77if (ent == NULL)
78       errx(1, "cap_getprotobyname failed to find http proto");
79.Ed
80.Sh SEE ALSO
81.Xr cap_enter 2 ,
82.Xr caph_enter 3 ,
83.Xr err 3 ,
84.Xr getprotobyname 3 ,
85.Xr capsicum 4 ,
86.Xr nv 9
87.Sh AUTHORS
88The
89.Nm cap_netdb
90service was implemented by
91.An Ryan Moeller Aq Mt freqlabs@FreeBSD.org .
92