.\" 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. All advertising materials mentioning features or use of this software
-.\" must display the following acknowledgement:
-.\" This product includes software developed by the University of
-.\" California, Berkeley and its contributors.
.\" 4. 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.
.\" SUCH DAMAGE.
.\"
.\" From: @(#)getgrent.3 8.2 (Berkeley) 4/19/94
-.\" $FreeBSD: src/lib/libc/gen/getgrent.3,v 1.16 2001/10/01 16:08:51 ru Exp $
+.\" $FreeBSD: src/lib/libc/gen/getgrent.3,v 1.28 2007/01/09 00:27:53 imp Exp $
.\"
-.Dd September 29, 1994
+.Dd April 16, 2003
.Dt GETGRENT 3
.Os
.Sh NAME
-.Nm endgrent ,
.Nm getgrent ,
-.Nm getgrgid ,
-.Nm getgrgid_r ,
+.\".Nm getgrent_r ,
.Nm getgrnam ,
.Nm getgrnam_r ,
+.Nm getgrgid ,
+.Nm getgrgid_r ,
+.Nm setgroupent ,
.Nm setgrent ,
-.\" .Nm setgrfile ,
-.Nm setgroupent
+.Nm endgrent
.Nd group database operations
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In grp.h
-.Ft void
-.Fo endgrent
-.Fa void
-.Fc
.Ft struct group *
-.Fo getgrent
-.Fa void
-.Fc
+.Fn getgrent void
+.\".Ft int
+.\".Fn getgrent_r "struct group *grp" "char *buffer" "size_t bufsize" "struct group **result"
.Ft struct group *
-.Fo getgrgid
-.Fa "gid_t gid"
-.Fc
+.Fn getgrnam "const char *name"
.Ft int
-.Fo getgrgid_r
-.Fa "gid_t gid"
-.Fa "struct group *grp"
-.Fa "char *buffer"
-.Fa "size_t bufsize"
-.Fa "struct group **result"
-.Fc
+.Fn getgrnam_r "const char *name" "struct group *grp" "char *buffer" "size_t bufsize" "struct group **result"
.Ft struct group *
-.Fo getgrnam
-.Fa "const char *name"
-.Fc
+.Fn getgrgid "gid_t gid"
.Ft int
-.Fo getgrnam_r
-.Fa "const char *name"
-.Fa "struct group *grp"
-.Fa "char *buffer"
-.Fa "size_t bufsize"
-.Fa "struct group **result"
-.Fc
-.Ft void
-.Fo setgrent
-.Fa void
-.Fc
-.\" .Ft void
-.\" .Fn setgrfile "const char *name"
+.Fn getgrgid_r "gid_t gid" "struct group *grp" "char *buffer" "size_t bufsize" "struct group **result"
+.Ft int
+.Fn setgroupent "int stayopen"
.Ft int
-.Fo setgroupent
-.Fa "int stayopen"
-.Fc
+.Fn setgrent void
+.Ft void
+.Fn endgrent void
.Sh DESCRIPTION
-These functions operate on the group database file
-.Pa /etc/group ,
+.\"These functions operate on the group database file
+These functions obtain information from
+.Xr DirectoryService 8 ,
+including records in
+.Pa /etc/group
which is described
in
.Xr group 5 .
Each line of the database is defined by the structure
-.Ar group ,
+.Vt group
found in the include
file
-.Aq Pa grp.h :
+.In grp.h :
.Bd -literal -offset indent
struct group {
char *gr_name; /* group name */
char *gr_passwd; /* group password */
- int gr_gid; /* group id */
+ gid_t gr_gid; /* group id */
char **gr_mem; /* group members */
};
.Ed
.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.
+search the group database for the given group name pointed to by
+.Fa name
+or the group id pointed to by
+.Fa gid ,
+respectively, returning the first one encountered.
+Identical group
+names or group gids may result in undefined behavior.
+.Pp
+On Mac OS X, these routines are thread-safe and return a pointer to a
+thread-specific data structure. The contents of this data
+structure are automatically released by subsequent calls to
+any of these routines on the same thread, or when the thread exits.
.Pp
-All of these routines are thread-safe.
The
-.Fn getgrent ,
-.Fn getgrgid ,
-and
-.Fn getgrnam
-routines return a pointer to a result managed by the system library in a
-thread-specific data structure.
-Every thread has space for a pointer to a struct group and allocates its own storage for the result.
-Neither previously returned values in memory nor a previously returned pointer value should be used
-by a thread after calling any one of these three routines.
-Memory allocated by a thread is automatically released on subsequent calls by the same thread to any of these
-three routines, and when the thread exits.
+.Fn getgrent
+function
+sequentially reads the group database and is intended for programs
+that wish to step through the complete list of groups.
.Pp
The functions
+.\".Fn getgrent_r ,
+.\".Fn getgrnam_r ,
+.Fn getgrnam_r
+and
.Fn getgrgid_r
+are thread-safe versions of
+.\".Fn getgrent ,
+.\".Fn getgrnam ,
+.Fn getgrnam
and
-.Fn getgrnam_r
-take additional arguments which supply storage space for the returned result.
-The
-.Fa grp
-parameter is a pointer to a struct group, which must be allocated by the caller.
-The
-.Fa buffer
-parameter is a pointer to a block of memory with a size specified by
-.Pa bufsize .
-This buffer is used to hold the values which are pointed to by values filled in
+.Fn getgrgid ,
+respectively.
+The caller must provide storage for the results of the search in
the
+.Fa grp ,
+.Fa buffer ,
+.Fa bufsize ,
+and
+.Fa result
+arguments.
+When these functions are successful, the
.Fa grp
-structure.
-Zero is returned on success.
-If insufficient memory is supplied, these routines return ERANGE.
+argument will be filled-in, and a pointer to that argument will be
+stored in
+.Fa result .
+If an entry is not found or an error occurs,
+.Fa result
+will be set to
+.Dv NULL .
.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 routines will open the group file for reading, if necessary.
+These functions will open the group file for reading, if necessary.
.Pp
The
.Fn setgroupent
function
-opens the file, or rewinds it if it is already open. If
+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
+functions subsequent calls.
+This functionality is unnecessary for
+.Fn getgrent
+as it does not 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.
+functionality as the group file may be updated.
.Pp
The
.Fn setgrent
.Sh RETURN VALUES
The functions
.Fn getgrent ,
+.Fn getgrnam ,
+and
.Fn getgrgid ,
+return a pointer to a group structure on success or
+.Dv NULL
+if the entry is not found or if an error occurs.
+If an error does occur,
+.Va errno
+will be set.
+Note that programs must explicitly set
+.Va errno
+to zero before calling any of these functions if they need to
+distinguish between a non-existent entry and an error.
+The functions
+.\".Fn getgrent_r ,
+.\".Fn getgrnam_r ,
+.Fn getgrnam_r
and
-.Fn getgrnam
-each return a pointer to the group entry if successful; if end-of-file
-is reached or an error occurs, a null pointer is returned.
-The function
+.Fn getgrgid_r
+return 0 if no error occurred, or an error number to indicate failure.
+It is not an error if a matching entry is not found.
+(Thus, if
+.Fa result
+is set to
+.Dv NULL
+and the return value is 0, no matching entry exists.)
+.Pp
+The functions
.Fn setgroupent
-returns the value 1 if successful;
-otherwise, the value 0 is returned.
+and
+.Fn setgrent
+return the value 1 if successful, otherwise the value
+0 is returned.
The functions
-.Fn endgrent ,
-.Fn setgrent ,
+.Fn endgrent
and
.Fn setgrfile
have no return value.
.It Pa /etc/group
group database file
.El
-.Sh LEGACY SYNOPSIS
-.Fd #include <grp.h>
-.Pp
-.Ft int
-.br
-.Fo setgrent
-.Fa void
-.Fc ;
-.Pp
-The function
-.Fn setgrent
-returns the value 1 if successful;
-otherwise, the value 0 is returned.
+.Sh COMPATIBILITY
+The historic function
+.Fn setgrfile ,
+which allowed the specification of alternate password databases, has
+been deprecated and is no longer available.
.Sh SEE ALSO
.Xr getpwent 3 ,
-.Xr yp 8 ,
-.Xr group 5
+.Xr group 5 ,
+.\".Xr nsswitch.conf 5 ,
+.Xr DirectoryService 8 ,
+.Xr yp 8
+.Sh STANDARDS
+The
+.Fn getgrent ,
+.Fn getgrnam ,
+.Fn getgrnam_r ,
+.Fn getgrgid ,
+.Fn getgrgid_r
+and
+.Fn endgrent
+functions conform to
+.St -p1003.1-96 .
+The
+.Fn setgrent
+function differs from that standard in that its return type is
+.Vt int
+rather than
+.Vt void .
.Sh HISTORY
The functions
.Fn endgrent ,
.Fn setgroupent
appeared in
.Bx 4.3 Reno .
-.Sh COMPATIBILITY
-The historic function
-.Fn setgrfile ,
-which allowed the specification of alternate password databases, has
-been deprecated and is no longer available.
+The functions
+.\".Fn getgrent_r ,
+.\".Fn getgrnam_r ,
+.Fn getgrnam_r
+and
+.Fn getgrgid_r
+appeared in
+.Fx 5.1 .
.Sh BUGS
The functions
.Fn getgrent ,
.Fn getgrnam ,
-and
.Fn getgrgid ,
-leave their results in internal thread-specific memory and return
+.Fn setgroupent
+and
+.Fn setgrent
+leave their results in an internal thread-specific memory and return
a pointer to that object.
-Subsequent calls to any of these three routines by the same thread will
-release the object and return a new pointer value.
+Subsequent calls to
+the same function
+will modify the same object.
+.\".Pp
+.\"The functions
+.\".Fn getgrent ,
+.\".Fn getgrent_r ,
+.\".Fn endgrent ,
+.\".Fn setgroupent ,
+.\"and
+.\".Fn setgrent
+.\"are fairly useless in a networked environment and should be
+.\"avoided, if possible.
+.\"The
+.\".Fn getgrent
+.\"and
+.\".Fn getgrent_r
+.\"functions
+.\"make no attempt to suppress duplicate information if multiple
+.\"sources are specified in
+.\".Xr nsswitch.conf 5 .
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