GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
Unix |
Unix v7 |
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getgrent(3) |
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getgrent, getgrgid, getgrnam, setgrent, endgrent − get group file entry
#include <grp.h>
struct group *getgrent();
struct group *getgrgid(gid) int gid;
struct group *getgrnam(name) char *name;
int setgrent();
int endgrent();
Getgrent, getgrgid and getgrnam each return pointers to an object with the following structure containing the broken-out fields of a line in the group file.
/* Copyright
(C) 1991,1992,1995-2001,2003,2004,2010
Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C
Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later
version.
The GNU C
Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty
of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU
Lesser General Public License for more details.
You should have
received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the
Free
Software Foundation, Inc., 59 Temple Place, Suite 330,
Boston, MA
02111-1307 USA. */
/*
|
POSIX Standard: 9.2.1 Group Database Access |
<grp.h> |
*/
|
#ifndef |
_GRP_H |
|||||
|
#define |
_GRP_H |
1 |
#include <features.h>
__BEGIN_DECLS
#include <bits/types.h>
#define
__need_size_t
#include <stddef.h>
/* For the
Single Unix specification we must define this type here. */
#if (defined __USE_XOPEN || defined __USE_XOPEN2K)
&& !defined __gid_t_defined
typedef __gid_t gid_t;
# define __gid_t_defined
#endif
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/* The group structure. |
*/ |
struct group
{
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/* Group name. |
*/ | ||||||||
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/* Password. |
*/ | ||||||||
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/* Group ID. |
*/ | ||||||||
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/* Member list. |
*/ |
};
#if defined
__USE_SVID || defined __USE_GNU
# define __need_FILE
# include <stdio.h>
#endif
#if defined
__USE_SVID || defined __USE_BSD || defined
__USE_XOPEN_EXTENDED
/* Rewind the group-file stream.
This function
is a possible cancellation point and therefore not
marked with __THROW. */
extern void setgrent (void);
#endif
#if defined
__USE_SVID || defined __USE_BSD || defined
__USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
/* Close the group-file stream.
This function
is a possible cancellation point and therefore not
marked with __THROW. */
extern void endgrent (void);
/* Read an entry from the group-file stream, opening it if necessary.
This function
is a possible cancellation point and therefore not
marked with __THROW. */
extern struct group *getgrent (void);
#endif
|
#ifdef |
__USE_SVID |
/* Read a group entry from STREAM.
This function
is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX
interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
extern struct group *fgetgrent (FILE *__stream);
#endif
#ifdef
__USE_GNU
/* Write the given entry onto the given stream.
This function
is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX
interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
extern int putgrent (__const struct group *__restrict
__p,
|
FILE *__restrict __f); |
#endif
/* Search for an entry with a matching group ID.
This function
is a possible cancellation point and therefore not
marked with __THROW. */
extern struct group *getgrgid (__gid_t __gid);
/* Search for an entry with a matching group name.
This function
is a possible cancellation point and therefore not
marked with __THROW. */
extern struct group *getgrnam (__const char *__name);
#if defined __USE_POSIX || defined __USE_MISC
# ifdef
__USE_MISC
/* Reasonable value for the buffer sized used in the
reentrant
functions below. But better use ’sysconf’.
*/
|
# define NSS_BUFLEN_GROUP |
1024 |
# endif
/* Reentrant versions of some of the functions above.
PLEASE NOTE:
the ’getgrent_r’ function is not (yet)
standardized.
The interface may change in later versions of this library.
But
the interface is designed following the principals used for
the
other reentrant functions so the chances are good this is
what the
POSIX people would choose.
This function
is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX
interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
# ifdef
__USE_GNU
extern int getgrent_r (struct group *__restrict
__resultbuf,
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char *__restrict __buffer, size_t __buflen, | |||
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struct group **__restrict __result); |
# endif
/* Search for an entry with a matching group ID.
This function
is a possible cancellation point and therefore not
marked with __THROW. */
extern int getgrgid_r (__gid_t __gid, struct group
*__restrict __resultbuf,
|
char *__restrict __buffer, size_t __buflen, | |||
|
struct group **__restrict __result); |
/* Search for an entry with a matching group name.
This function
is a possible cancellation point and therefore not
marked with __THROW. */
extern int getgrnam_r (__const char *__restrict __name,
|
struct group *__restrict __resultbuf, | ||||
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char *__restrict __buffer, size_t __buflen, | ||||
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struct group **__restrict __result); | ||||
|
# ifdef |
__USE_SVID |
/* Read a group entry from
STREAM. This function is not standardized
an probably never will.
This function
is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX
interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
extern int fgetgrent_r (FILE *__restrict __stream,
|
struct group *__restrict __resultbuf, | ||||
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char *__restrict __buffer, size_t __buflen, | ||||
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struct group **__restrict __result); |
# endif
|
#endif |
/* POSIX or reentrant */ | |||
|
#ifdef |
__USE_BSD |
# define
__need_size_t
# include <stddef.h>
/* Set the
group set for the current user to GROUPS (N of them). */
extern int setgroups (size_t __n, __const __gid_t *__groups)
__THROW;
/* Store at
most *NGROUPS members of the group set for USER into
*GROUPS. Also include GROUP. The actual number of groups
found is
returned in *NGROUPS. Return -1 if the if *NGROUPS is too
small.
This function
is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX
interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
extern int getgrouplist (__const char *__user, __gid_t
__group,
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__gid_t *__groups, int *__ngroups); |
/* Initialize
the group set for the current user
by reading the group database and using all groups
of which USER is a member. Also include GROUP.
This function
is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX
interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
extern int initgroups (__const char *__user, __gid_t
__group);
#endif /* Use BSD. */
__END_DECLS
#endif /* grp.h */
The members of
this structure are:
gr_name
The name of the group.
gr_passwd
The encrypted password of the group.
|
gr_gid |
The numerical group-ID. | ||
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gr_mem |
Null-terminated vector of pointers to the individual member names. |
Getgrent simply reads the next line while getgrgid and getgrnam search until a matching gid or name is found (or until EOF is encountered). Each routine picks up where the others leave off so successive calls may be used to search the entire file.
A call to setgrent has the effect of rewinding the group file to allow repeated searches. Endgrent may be called to close the group file when processing is complete.
/etc/group
getlogin(3), getpwent(3), group(5)
A null pointer (0) is returned on EOF or error.
All information is contained in a static area so it must be copied if it is to be saved.
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getgrent(3) | |