Provided by: freebsd-manpages_10.1~RC1-1_all bug

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 memory 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 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.

     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.