 @@ -1,344 +1,344 @@
-.\"	$NetBSD: getgrent.3,v 1.30 2010/03/22 19:30:53 joerg Exp $
+.\"	$NetBSD: getgrent.3,v 1.31 2011/04/28 16:34:01 wiz Exp $
 .\"
 .\" Copyright (c) 1989, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
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 .\" modification, are permitted provided that the following conditions
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 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 .\"    documentation and/or other materials provided with the distribution.
 .\" 3. Neither the name of the University nor the names of its contributors
 .\"    may be used to endorse or promote products derived from this software
 .\"    without specific prior written permission.
 .\"
 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 .\"
 .\"     @(#)getgrent.3	8.2 (Berkeley) 4/19/94
 .\"
 .Dd April 30, 2008
 .Dt GETGRENT 3
 .Os
 .Sh NAME
 .Nm getgrent ,
 .Nm getgrent_r ,
 .Nm getgrgid ,
 .Nm getgrgid_r ,
 .Nm getgrnam ,
 .Nm getgrnam_r ,
 .Nm setgroupent ,
 .\" .Nm setgrfile ,
 .Nm setgrent ,
 .Nm endgrent
 .Nd group database operations
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
 .In grp.h
 .Ft struct group *
 .Fn getgrent void
 .Ft int
 .Fo getgrent_r
 .Fa "struct group *grp"
 .Fa "char *buffer"
 .Fa "size_t buflen"
 .Fa "struct group **result"
 .Fc
 .Ft struct group *
 .Fn getgrgid "gid_t gid"
 .Ft int
 .Fo getgrgid_r
 .Fa "gid_t gid"
 .Fa "struct group *grp"
 .Fa "char *buffer"
 .Fa "size_t buflen"
 .Fa "struct group **result"
 .Fc
 .Ft struct group *
 .Fn getgrnam "const char *name"
 .Ft int
 .Fo getgrnam_r
 .Fa "const char *name"
 .Fa "struct group *grp"
 .Fa "char *buffer"
 .Fa "size_t buflen"
 .Fa "struct group **result"
 .Fc
 .Ft int
 .Fn setgroupent "int stayopen"
 .\" .Ft void
 .\" .Fn setgrfile "const char *name"
 .Ft void
 .Fn setgrent void
 .Ft void
 .Fn endgrent void
 .Sh DESCRIPTION
 These functions operate on the group database which is described in
 .Xr group 5 .
 Each line of the database is defined by the structure
 .Ar group
 found in the include
 file
 .In grp.h :
 .Bd -literal -offset indent
 struct group {
 	char	*gr_name;	/* group name */
 	char	*gr_passwd;	/* group password */
 	gid_t	gr_gid;		/* group id */
 	char	**gr_mem;	/* group members */
 };
 .Ed
 .Pp
 The functions
 .Fn getgrnam
 and
 .Fn getgrgid
 search the group database for the given group name pointed to by
 .Ar name
 or the group id pointed to by
 .Ar gid ,
 respectively, returning the first one encountered.
 Identical group names or group ids may result in undefined behavior.
 .Pp
 The
 .Fn getgrent
 function sequentially reads the group database and is intended for programs
 that wish to step through the complete list of groups.
 .Pp
 All three functions will open the group file for reading, if necessary.
 .Pp
 The functions
 .Fn getgrnam_r ,
 .Fn getgrgid_r ,
 and
 .Fn getgrent_r
 act like their non re-entrant counterparts
 respectively, updating the contents of
 .Ar grp
 and storing a pointer to that in
 .Ar result ,
 and returning
 .Dv 0 .
 Storage used by
 .Ar grp
 is allocated from
 .Ar buffer ,
 which is
 .Ar buflen
 bytes in size.
 If the requested entry cannot be found,
 .Ar result
 will point to
 .Dv NULL
 and
 .Dv 0
 will be returned.
 If an error occurs,
 a non-zero error number will be returned and
 .Ar result
 will point to
 .Dv NULL .
 Calling
 .Fn getgrent_r
 from multiple threads will result in each thread reading a disjoint portion
 of the group database.
 .Pp
 The
 .Fn setgroupent
 function opens the file, or rewinds it if it is already open.
 If
 .Fa stayopen
 is non-zero, file descriptors are left open, significantly speeding
 functions subsequent calls.
 This functionality is unnecessary for
 .Fn getgrent
 as it doesn't close its file descriptors by default.
 It should also be noted that it is dangerous for long-running
 programs to use this functionality as the group file may be updated.
 .Pp
 The
 .Fn setgrent
 function is equivalent to
 .Fn setgroupent
 with an argument of zero.
 .Pp
 The
 .Fn endgrent
 function closes any open files.
 .Sh RETURN VALUES
 The functions
 .Fn getgrgid ,
 .Fn getgrnam ,
 and
 .Fn getgrent
 return a valid pointer to a group structure on success
 and a
 .Dv NULL
 pointer if the entry was not found or an error occured.
 If an error occured, the global variable
 .Dv errno
 is set to indicate the nature of the failure.
 .Pp
 The functions
 .Fn getgrgid_r ,
 .Fn getgrnam_r ,
 and
 .Fn getgrent_r
 return
 .Dv 0
 on success or entry not found, and non-zero on failure, setting the global
 variable
 .Dv errno
 to indicate the nature of the failure.
 .Pp
 The
 .Fn setgroupent
 function returns the value 1 if successful, otherwise the value
 is returned, setting the global variable
 .Dv errno
 to indicate the nature of the failure.
 .Pp
 The
 .Fn endgrent
 and
 .Fn setgrent
 functions have no return value.
 .Sh FILES
 .Bl -tag -width /etc/group -compact
 .It Pa /etc/group
 group database file
 .El
 .Sh COMPATIBILITY
 The historic function
 .Fn setgrfile ,
 which allowed the specification of alternative group databases, has
 been deprecated and is no longer available.
 .Sh ERRORS
 The following error codes may be set in
 .Va errno
 for
 .Nm getgrent ,
 .Nm getgrent_r ,
 .Nm getgrnam ,
 .Nm getgrnam_r ,
 .Nm getgrgid ,
 .Nm getgrgid_r ,
 and
 .Nm setgroupent :
 .Bl -tag -width Er
 .It Bq Er EIO
 An I/O error has occurred.
 .It Bq Er EINTR
 A signal was caught during the database search.
 .It Bq Er EIO
 An I/O error has occurred.
 .It Bq Er EMFILE
 The limit on open files for this process has been reached.
 .It Bq Er ENFILE
 The system limit on open files has been reached.
 .El
 .Pp
 The following error code may be set in
 .Va errno
 for
 .Nm getgrent_r ,
 .Nm getgrnam_r ,
 and
 .Nm getgrgid_r :
 .Bl -tag -width Er
 .It Bq Er ERANGE
 The resulting
 .Ft struct group
 does not fit in the space defined by
 .Dv buffer
 and
 .Dv buflen
 .El
 .Pp
 Other
 .Dv errno
 values may be set depending on the specific database backends.
 .Sh FILES
 .Bl -tag -width /etc/group -compact
 .It Pa /etc/group
 group database file
 .El
 .Sh SEE ALSO
 .Xr getpwent 3 ,
 .Xr group 5 ,
 .Xr nsswitch.conf 5
 .Sh STANDARDS
 The
 .Fn getgrgid
 and
 .Fn getgrnam
 functions conform to
 .St -p1003.1-90 .
 The
 .Fn getgrgid_r
 and
 .Fn getgrnam_r
 functions conform to
 .St -p1003.1c-95 .
 The
 .Fn endgrent ,
 .Fn getgrent ,
 and
 .Fn setgrent
 functions conform to
 .St -xpg4.2
 and
 .St -p1003.1-2004
 (XSI extension).
 .Sh HISTORY
 The functions
 .Fn endgrent ,
 .Fn getgrent ,
 .Fn getgrgid ,
 .Fn getgrnam ,
 and
 .Fn setgrent
 appeared in
 .At v7 .
 The functions
 .Fn setgrfile
 and
 .Fn setgroupent
 appeared in
 .Bx 4.3 Reno .
 The functions
 .Fn getgrgid_r
 and
 .Fn getgrnam_r
 appeared in
 .Nx 3.0 .
 .Sh COMPATIBILITY
 The historic function
 .Fn setgrfile ,
 which allowed the specification of alternative group databases, has
 been deprecated and is no longer available.
 .Sh BUGS
 The functions
 .Fn getgrent ,
 .Fn getgrgid ,
 .Fn getgrnam ,
 .Fn setgroupent
 and
 .Fn setgrent
 leave their results in an internal static object and return
 a pointer to that object.
 Subsequent calls to the same function will modify the same object.
 .Pp
 The functions
 .Fn getgrent ,
 .Fn endgrent ,
 .Fn setgroupent ,
 and
 .Fn setgrent
 are fairly useless in a networked environment and should be
 avoided, if possible.
 .Fn getgrent
 makes no attempt to suppress duplicate information if multiple
 sources are specified in
 .Xr nsswitch.conf 5