обрабатывать записи сетевых групп (handle network group entries)
Имя (Name)
setnetgrent, endnetgrent, getnetgrent, getnetgrent_r, innetgr -
handle network group entries
Синопсис (Synopsis)
#include <netdb.h>
int setnetgrent(const char *netgroup);
void endnetgrent(void);
int getnetgrent(char **restrict host,
char **restrict user, char **restrict domain);
int getnetgrent_r(char **restrict host,
char **restrict user, char **restrict domain,
char *restrict buf, size_t 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():
Since glibc 2.19:
_DEFAULT_SOURCE
Glibc 2.19 and earlier:
_BSD_SOURCE || _SVID_SOURCE
Описание (Description)
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.
Возвращаемое значение (Return value)
These functions return 1 on success and 0 for failure.
Файлы (Files)
/etc/netgroup
/etc/nsswitch.conf
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌─────────────────┬───────────────┬──────────────────────────────┐
│Interface │ Attribute │ Value │
├─────────────────┼───────────────┼──────────────────────────────┤
│setnetgrent(), │ Thread safety │ MT-Unsafe race:netgrent │
│getnetgrent_r(), │ │ locale │
│innetgr() │ │ │
├─────────────────┼───────────────┼──────────────────────────────┤
│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(), getnetgrent_r(), innetgr(),
getnetgrent(), or endnetgrent() are used in parallel in different
threads of a program, then data races could occur.
Стандарты (Conforming to)
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.
Примечание (Note)
In the BSD implementation, setnetgrent() returns void.
Смотри также (See also)
sethostent(3), setprotoent(3), setservent(3)
