getnetgrent.3c (2010 09)

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getnetgrent(3C) getnetgrent(3C)

NAME

getnetgrent( ), setnetgrent( ), endnetgrent( ), innetgr( ), - get network group entry

SYNOPSIS

int innetgr(

char *netgroup,

char *machine,

char *user,

char *domain

);

int setnetgrent(char *netgroup);

int endnetgrent();

int getnetgrent(

char **machinep,

char **userp,

char **domainp

);

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 net-

work 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; i.e.:

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,ordp is NULL, it signiﬁes that the element of the netgroup contains 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 multi-threaded 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 sub-

set of the netgroup. Thus the effective use of these functions in multi-threaded applications may require

coordination by the caller.

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (2 pages)

PAGE 1
getnetgrent(3C) getnetgrent(3C) NAME getnetgrent( ), setnetgrent( ), endnetgrent( ), innetgr( ), - get network group entry SYNOPSIS int innetgr( char *netgroup, char *machine, char *user, char *domain ); int setnetgrent(char *netgroup); int endnetgrent(); int getnetgrent( char **machinep, char **userp, char **domainp ); DESCRIPTION These functions are used to test membership in and enumerate members of ‘‘netgroup’’ network groups defined in a system database.
PAGE 2
getnetgrent(3C) MULTITHREAD USAGE Thread Safe: Cancel Safe: Fork Safe: Async-cancel Safe: Async-signal Safe: getnetgrent(3C) Yes Yes No No No These functions can be called safely in a multithreaded environment. They may be cancellation points in that they call functions that are cancel points. In a multithreaded environment, these functions are not safe to be called by a child process after fork() and before exec().