setnetgrent, endnetgrent, getnetgrent, getnetgrent_r, innetgr — handle network group entries
#include <netdb.h>
int
setnetgrent( |
const char *netgroup) ; |
void
endnetgrent( |
void) ; |
int
getnetgrent( |
char **host, |
char **user, | |
char **domain) ; |
int
getnetgrent_r( |
char **host, |
char **user, | |
char **domain, | |
char *buf, | |
size_t buflen) ; |
int
innetgr( |
const char *netgroup, |
const char *host, | |
const char *user, | |
const char *domain) ; |
Note | |||||
---|---|---|---|---|---|
|
The netgroup
is a
SunOS invention. A netgroup database is a list of string
triples (hostname
,
username
,
domainname
) or
other netgroup names. Any of the elements in a triple can be
empty, which means that anything matches. The functions
described here allow access to the netgroup databases. The
file /etc/nsswitch.conf
defines
what database is searched.
The setnetgrent
() call
defines the netgroup that will be searched by subsequent
getnetgrent
() calls. The
getnetgrent
() function
retrieves the next netgroup entry, and returns pointers in
host
, user
, domain
. A null pointer means
that the corresponding entry matches any string. The pointers
are valid only as long as there is no call to other
netgroup-related functions. To avoid this problem you can use
the GNU function getnetgrent_r
() that stores the strings in
the supplied buffer. To free all allocated buffers use
endnetgrent
().
In most cases you want to check only if the triplet
(hostname
,
username
,
domainname
) is a
member of a netgroup. The function innetgr
() can be used for this without
calling the above three functions. Again, a null pointer is a
wildcard and matches any string. The function is
thread-safe.
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
setnetgrent (),getnetgrent_r (),
innetgr ()
|
Thread safety |
MT-Unsafe race:netgrent locale |
endnetgrent () |
Thread safety | MT-Unsafe race:netgrent |
getnetgrent () |
Thread safety |
MT-Unsafe race:netgrent race:netgrentbuf locale |
In the above table, netgrent
in race:netgrent
signifies that if any of the functions setnetgrent(3), getnetgrent_r(3), innetgr(3), getnetgrent(3), or
endnetgrent(3) are used in
parallel in different threads of a program, then data races
could occur.
These functions are not in POSIX.1, but setnetgrent
(), endnetgrent
(), getnetgrent
(), and innetgr
() are available on most UNIX
systems. getnetgrent_r
() is not
widely available on other systems.
This page is part of release 4.07 of the Linux man-pages
project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
Copyright 2002 walter harms (walter.harmsinformatik.uni-oldenburg.de) %%%LICENSE_START(GPL_NOVERSION_ONELINE) Distributed under GPL %%%LICENSE_END based on glibc infopages polished - aeb |