HP-UX Reference (11i v2 07/12) - 3 Library Functions A-M (vol 6)

g
getnetgrent(3C) getnetgrent(3C)
NAME
getnetgrent(), setnetgrent(), endnetgrent(), innetgr() - get network group entry
SYNOPSIS
int getnetgrent(
char **machinep,
char **userp,
char **domainp
);
int setnetgrent(char *netgroup);
int endnetgrent();
int innetgr(
char *netgroup,
char *machine,
char *user,
char *domain
);
DESCRIPTION
These functions are used to test membership in and enumerate members of "netgroup" network groups
defined in a system database. Netgroups are sets of (machine,user,domain
) triples (see netgroup(4)).
These functions consult the source specified for
netgroup in the /etc/nsswitch.conf
file (see
nsswitch.conf(4)).
The function
innetgr() returns 1 if there is a netgroup netgroup that contains the specified machine,
user, domain triple as a member; otherwise it returns
0. Any of the supplied pointers machine, user, and
domain may be
NULL, signifying a "wild card" that matches all values in that position of the triple.
The innetgr() function is safe for use in multithreaded applications.
The functions setnetgrent(), getnetgrent()
, and endnetgrent() are used to enumerate the
members of a given network group.
The function
setnetgrent() establishes the network group specified in the parameter netgroup as the
current group whose members are to be enumerated.
Successive calls to the function
getnetgrent()
will enumerate the members of the group established by
calling
setnetgrent(); each call returns 1 if it succeeds in obtaining another member of the network
group, or 0 if there are no further members of the group.
When calling getnetgrent(), addresses of the three character pointers are used as arguments; for
example,
char *mp, *up, *dp;
getnetgrent(&mp, &up, &dp);
Upon successful return from getnetgrent()
, the pointer mp points to a thread-specific storage area
containing the name of the machine part of the member triple,
up points to a thread-specific storage area
containing the user name and dp points to a thread-specific storage area containing the domain name. If
the pointer returned for mp, up,or dp is NULL, it signifies that the element of the netgroup contains a
wild-card specifier in that position of the triple.
The storage allocated by setnetgrent() is released when an endnetgrent()
call is made, and
should not be released by the caller.
The function
endnetgrent() frees the space allocated by the previous setnetgrent()
call. The
equivalent of an
endnetgrent() implicitly performed whenever a setnetgrent() call is made to a
new network group.
Note that while
setnetgrent() and endnetgrent() are safe for use in multithreaded applications,
the effect of each is process-wide. Calling
setnetgrent()
resets the enumeration position for all
threads. If multiple threads interleave calls to
getnetgrent_r() each will enumerate a disjoint subset
of the netgroup. Thus the effective use of these functions in multithreaded applications may require coordi-
nation by the caller.
HP-UX 11i Version 2: December 2007 Update − 1 − Hewlett-Packard Company 511