minix/lib/libc/sys/issetugid.2
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

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Groff

.\" $NetBSD: issetugid.2,v 1.11 2003/08/07 16:44:00 agc Exp $
.\" OpenBSD: issetugid.2,v 1.7 1997/02/18 00:16:09 deraadt Exp
.\" FreeBSD: src/lib/libc/sys/issetugid.2,v 1.5.2.2 1999/09/18 16:18:59 phantom Exp
.\"
.\" Copyright (c) 1980, 1991, 1993
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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
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.\" 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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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" SUCH DAMAGE.
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.\" FreeBSD: src/lib/libc/sys/issetugid.2,v 1.5.2.2 1999/09/18 16:18:59 phantom Exp
.\"
.Dd April 22, 2000
.Dt ISSETUGID 2
.Os
.Sh NAME
.Nm issetugid
.Nd is current process tainted by uid or gid changes
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn issetugid void
.Sh DESCRIPTION
The
.Fn issetugid
function returns 1 if the process environment or memory address space
is considered
.Dq tainted ,
and returns 0 otherwise.
.Pp
A process is tainted if it was created as a result of an
.Xr execve 2
system call which had either of the setuid or setgid bits set (and extra
privileges were given as a result) or if it has changed any of its real,
effective or saved user or group ID's since it began execution.
.Pp
This system call exists so that library routines (e.g., libc, libtermcap)
can reliably determine if it is safe to use information
that was obtained from the user, in particular the results from
.Xr getenv 3
should be viewed with suspicion if it is used to control operation.
.Pp
A
.Dq tainted
status is inherited by child processes as a result of the
.Xr fork 2
system call (or other library code that calls fork, such as
.Xr popen 3 ) .
.Pp
It is assumed that a program that clears all privileges as it prepares
to execute another will also reset the environment, hence the
.Dq tainted
status will not be passed on.
This is important for programs such as
.Xr su 1
which begin setuid but need to be able to create an untainted process.
.Sh ERRORS
The
.Fn issetugid
function is always successful, and no return value is reserved to
indicate an error.
.Sh SEE ALSO
.Xr execve 2 ,
.Xr fork 2 ,
.Xr setegid 2 ,
.Xr seteuid 2 ,
.Xr setgid 2 ,
.Xr setregid 2 ,
.Xr setreuid 2 ,
.Xr setuid 2
.Sh HISTORY
A
.Fn issetugid
function call first appeared in
.Ox 2.0
and was also implemented in
.Fx 3.0 .
.Fx
implementation was imported in
.Nx 1.5 .