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ISSETUGID(2)		  FreeBSD System Calls Manual		  ISSETUGID(2)

NAME
     issetugid -- is current process tainted by	uid or gid changes

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #include <unistd.h>

     int
     issetugid(void);

DESCRIPTION
     The issetugid() system call returns 1 if the process environment or mem-
     ory address space is considered ``tainted'', and returns 0	otherwise.

     A process is tainted if it	was created as a result	of an execve(2)	system
     call which	had either of the setuid or setgid bits	set (and extra privi-
     leges 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.

     This system call exists so	that library routines (eg: libc, libtermcap)
     can reliably determine if it is safe to use information that was obtained
     from the user, in particular the results from getenv(3) should be viewed
     with suspicion if it is used to control operation.

     A ``tainted'' status is inherited by child	processes as a result of the
     fork(2) system call (or other library code	that calls fork, such as
     popen(3)).

     It	is assumed that	a program that clears all privileges as	it prepares to
     execute another will also reset the environment, hence the	``tainted''
     status will not be	passed on.  This is important for programs such	as
     su(1) which begin setuid but need to be able to create an untainted
     process.

ERRORS
     The issetugid() system call is always successful, and no return value is
     reserved to indicate an error.

SEE ALSO
     execve(2),	fork(2), setegid(2), seteuid(2), setgid(2), setregid(2),
     setreuid(2), setuid(2)

HISTORY
     The issetugid() system call first appeared	in OpenBSD 2.0 and was also
     implemented in FreeBSD 3.0.

FreeBSD	10.1			August 25, 1996			  FreeBSD 10.1

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | ERRORS | SEE ALSO | HISTORY

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