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Diffstat (limited to 'lib/libc/gen/getgrent.3')
| -rw-r--r-- | lib/libc/gen/getgrent.3 | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/lib/libc/gen/getgrent.3 b/lib/libc/gen/getgrent.3 new file mode 100644 index 0000000..e0e2782 --- /dev/null +++ b/lib/libc/gen/getgrent.3 @@ -0,0 +1,192 @@ +.\" Copyright (c) 1989, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" 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. 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. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)getgrent.3 8.2 (Berkeley) 4/19/94 +.\" +.Dd April 19, 1994 +.Dt GETGRENT 3 +.Os +.Sh NAME +.Nm getgrent , +.Nm getgrnam , +.Nm getgrgid , +.Nm setgroupent , +.\" .Nm setgrfile , +.Nm setgrent , +.Nm endgrent +.Nd group database operations +.Sh SYNOPSIS +.Fd #include <grp.h> +.Ft struct group * +.Fn getgrent void +.Ft struct group * +.Fn getgrnam "const char *name" +.Ft struct group * +.Fn getgrgid "gid_t gid" +.Ft struct group * +.Fn setgroupent "int stayopen" +.\" .Ft void +.\" .Fn setgrfile "const char *name" +.Ft int +.Fn setgrent void +.Ft void +.Fn endgrent void +.Sh DESCRIPTION +These functions operate on the group database file +.Pa /etc/group +which is described +in +.Xr group 5 . +Each line of the database is defined by the structure +.Ar group +found in the include +file +.Aq Pa 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 gids 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 routines 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 +.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 identical to +.Fn setgroupent +with an argument of zero. +.Pp +The +.Fn endgrent +function +closes any open files. +.Sh RETURN VALUES +The functions +.Fn getgrent , +.Fn getgrnam , +and +.Fn getgrgid , +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 functions +.Fn setgroupent +and +.Fn setgrent +return the value 1 if successful, otherwise the value +0 is returned. +The functions +.Fn endgrent +and +.Fn setgrfile +have no return value. +.Sh FILES +.Bl -tag -width /etc/group -compact +.It Pa /etc/group +group database file +.El +.Sh SEE ALSO +.Fn getpwent 3 , +.Fn group 5 +.Sh HISTORY +The functions +.Fn endgrent , +.Fn getgrent , +.Fn getgrnam , +.Fn getgrgid , +and +.Fn setgrent +appeared in +.At v7 . +The functions +.Fn setgrfile +and +.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. +.Sh BUGS +The functions +.Fn getgrent , +.Fn getgrnam , +.Fn getgrgid , +.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. |
