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) ; |
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.
sethostent(3), setservent(3), setprotoent(3)
|