SETUID(2) System Calls Manual SETUID(2)NAME
setuid, setgid - set user or group ID's
SYNOPSIS
#include <sys/types.h>
int setuid(uid_t uid)
int setgid(gid_t gid)
DESCRIPTION
Setuid sets the real and effective user ID's of the current process to uid. Unprivileged users may only change both user ID's to the real
user ID; only the super-user may make other changes. Setgid does the same for the real and effective group ID's.
Minix-vmd allows an unprivileged user to change ID's to the original real or effective ID as they were at the time the process was exe-
cuted. Setgid may also set the group ID's to any of the additional group ID's. If one of the remembered user ID's was 0 then any user or
group ID may be chosen.
RETURN VALUE
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error.
ERRORS
[EPERM] The current process is not the super-user and a change other than one of the allowed changes was attempted.
SEE ALSO getuid(2), getgid(2).
4th Berkeley Distribution May 9, 1985 SETUID(2)
Check Out this Related Man Page
SETUID(2) BSD System Calls Manual SETUID(2)NAME
setegid, seteuid, setgid, setuid -- set user and group ID
SYNOPSIS
#include <unistd.h>
int
setegid(gid_t egid);
int
seteuid(uid_t euid);
int
setgid(gid_t gid);
int
setuid(uid_t uid);
DESCRIPTION
The setuid() function sets the real and effective user IDs and the saved set-user-ID of the current process to the specified value. The
setuid() function is permitted if the effective user ID is that of the super user, or if the specified user ID is the same as the effective
user ID. If not, but the specified user ID is the same as the real user ID, setuid() will set the effective user ID to the real user ID.
The setgid() function sets the real and effective group IDs and the saved set-group-ID of the current process to the specified value. The
setgid() function is permitted if the effective user ID is that of the super user, or if the specified group ID is the same as the effective
group ID. If not, but the specified group ID is the same as the real group ID, setgid() will set the effective group ID to the real group
ID.
The seteuid() function (setegid()) sets the effective user ID (group ID) of the current process. The effective user ID may be set to the
value of the real user ID or the saved set-user-ID (see intro(2) and execve(2)); in this way, the effective user ID of a set-user-ID exe-
cutable may be toggled by switching to the real user ID, then re-enabled by reverting to the set-user-ID value. Similarly, the effective
group ID may be set to the value of the real group ID or the saved set-user-ID.
RETURN VALUES
Upon success, these functions return 0; otherwise -1 is returned.
If the user is not the super user, or the uid specified is not the real, effective ID, or saved ID, these functions return -1.
ERRORS
The setegid(), seteuid(), setgid(), and setuid() system calls will fail if:
[EINVAL] The value of the {group,user} ID argument is invalid and is not supported by the implementation.
[EPERM] The process does not have appropriate privileges and the ID argument does not match the real ID or the saved
set-{group,user}-ID.
LEGACY SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
The include file <sys/types.h> is necessary for all functions.
SEE ALSO getgid(2), getuid(2), compat(5)STANDARDS
The setuid() and setgid() functions are compliant with the ISO/IEC 9945-1:1990 (``POSIX.1'') specification with _POSIX_SAVED_IDS defined,
with the extensions allowed in section B.4.2.2. The seteuid() and setegid() functions are extensions based on the POSIX concept of
_POSIX_SAVED_IDS, and have been proposed for a future revision of the standard.
4.2 Berkeley Distribution June 4, 1993 4.2 Berkeley Distribution