1 files changed, 126 insertions, 0 deletions
diff --git a/lib/libc/sys/getlogin.2 b/lib/libc/sys/getlogin.2
new file mode 100644
index 0000000..5b351ca
--- /dev/null
+++ b/lib/libc/sys/getlogin.2
@@ -0,0 +1,126 @@
+.\" 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.
+.\"
+.\"	@(#)getlogin.2	8.1 (Berkeley) 6/9/93
+.\"
+.Dd June 9, 1993
+.Dt GETLOGIN 2
+.Os BSD 4.2
+.Sh NAME
+.Nm getlogin ,
+.Nm setlogin
+.Nd get/set login name
+.Sh SYNOPSIS
+.Fd #include <unistd.h>
+.Ft char *
+.Fn getlogin void
+.Ft int
+.Fn setlogin "const char *name"
+.Sh DESCRIPTION
+The
+.Fn getlogin
+routine
+returns the login name of the user associated with the current session,
+as previously set by
+.Fn setlogin .
+The name is normally associated with a login shell
+at the time a session is created,
+and is inherited by all processes descended from the login shell.
+(This is true even if some of those processes assume another user ID,
+for example when
+.Xr su 1
+is used.)
+.Pp
+.Fn Setlogin
+sets the login name of the user associated with the current session to
+.Fa name .
+This call is restricted to the super-user, and
+is normally used only when a new session is being created on behalf
+of the named user
+(for example, at login time, or when a remote shell is invoked).
+.Sh RETURN VALUES
+If a call to
+.Fn getlogin
+succeeds, it returns a pointer to a null-terminated string in a static buffer.
+If the name has not been set, it returns
+.Dv NULL .
+If a call to
+.Fn setlogin
+succeeds, a value of 0 is returned.  If
+.Fn setlogin
+fails, a value of -1 is returned and an error code is
+placed in the global location
+.Va errno .
+.Sh ERRORS
+The following errors may be returned by these calls:
+.Bl -tag -width Er
+.It Bq Er EFAULT
+The
+.Fa name
+parameter gave an
+invalid address.
+.It Bq Er EINVAL
+The
+.Fa name
+parameter
+pointed to a string that was too long.
+Login names are limited to
+.Dv MAXLOGNAME
+(from
+.Ao Pa sys/param.h Ac )
+characters, currently 12.
+.It Bq Er EPERM
+The caller tried to set the login name and was not the super-user.
+.El
+.Sh SEE ALSO
+.Xr setsid 2
+.Sh BUGS
+Login names are limited in length by
+.Fn setlogin .
+However, lower limits are placed on login names elsewhere in the system
+.Pf ( Dv UT_NAMESIZE
+in
+.Ao Pa utmp.h Ac ) .
+.Pp
+In earlier versions of the system,
+.Fn getlogin
+failed unless the process was associated with a login terminal.
+The current implementation (using
+.Fn setlogin )
+allows getlogin to succeed even when the process has no controlling terminal.
+In earlier versions of the system, the value returned by
+.Fn getlogin
+could not be trusted without checking the user ID.
+Portable programs should probably still make this check.
+.Sh HISTORY
+The
+.Fn getlogin
+function first appeared in 4.4BSD.