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SETNETGRENT(3) Linux Programmer's Manual SETNETGRENT(3)
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, int buflen);
int innetgr(const char *netgroup, const char *host,
const char *user, const char *domain);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
setnetgrent(), endnetgrent(), getnetgrent(), getnetgrent_r(), innetgr():
_BSD_SOURCE || _SVID_SOURCE
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 only want to check 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.
These functions return 1 on success and 0 for failure.
/etc/netgroup
/etc/nsswitch.conf
These functions are not in POSIX.1-2001, but setnetgrent(), endnetgrent(),
getnetgrent(), and innetgr() are available on most UNIX systems.
getnetgrent_r() is not widely available on other systems.
In the BSD implementation, setnetgrent() returns void.
sethostent(3), setprotoent(3), setservent(3)
This page is part of release 3.32 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
GNU 2007-07-26 SETNETGRENT(3)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface