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ISSETUGID(2)                BSD 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 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 pro-grams programs
     grams 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.

BSD                             August 25, 1996                            BSD