NAME

       setresuid, setresgid - set real, effective and saved user or group ID

SYNOPSIS

       #define _GNU_SOURCE         /* See feature_test_macros(7) */
       #include <unistd.h>

       int setresuid(uid_t ruid, uid_t euid, uid_t suid);
       int setresgid(gid_t rgid, gid_t egid, gid_t sgid);

DESCRIPTION

       setresuid()  sets  the  real  user  ID,  the  effective user ID, and the saved set-user-ID of the calling
       process.

       Unprivileged user processes may change the real UID, effective UID, and saved set-user-ID,  each  to  one
       of: the current real UID, the current effective UID or the current saved set-user-ID.

       Privileged  processes  (on Linux, those having the CAP_SETUID capability) may set the real UID, effective
       UID, and saved set-user-ID to arbitrary values.

       If one of the arguments equals -1, the corresponding value is not changed.

       Regardless of what changes are made to the real UID, effective UID, and saved set-user-ID, the filesystem
       UID is always set to the same value as the (possibly new) effective UID.

       Completely  analogously,  setresgid()  sets  the  real  GID, effective GID, and saved set-group-ID of the
       calling process (and always modifies the filesystem GID to be the same as the effective  GID),  with  the
       same restrictions for unprivileged processes.

RETURN VALUE

       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

ERRORS

       EAGAIN uid  does  not  match the current UID and this call would bring that user ID over its RLIMIT_NPROC
              resource limit.

       EPERM  The calling process is not privileged (did not have the CAP_SETUID capability) and tried to change
              the IDs to values that are not permitted.

VERSIONS

       These calls are available under Linux since Linux 2.1.44.

CONFORMING TO

       These calls are nonstandard; they also appear on HP-UX and some of the BSDs.

NOTES

       Under  HP-UX and FreeBSD, the prototype is found in <unistd.h>.  Under Linux the prototype is provided by
       glibc since version 2.3.2.

       The original Linux setresuid() and setresgid() system calls supported only 16-bit  user  and  group  IDs.
       Subsequently,  Linux  2.4  added  setresuid32()  and  setresgid32(),  supporting  32-bit  IDs.  The glibc
       setresuid() and setresgid() wrapper functions  transparently  deal  with  the  variations  across  kernel
       versions.

SEE ALSO

       getresuid(2),    getuid(2),    setfsgid(2),   setfsuid(2),   setreuid(2),   setuid(2),   capabilities(7),
       credentials(7)

COLOPHON

       This page is part of release 3.54 of the Linux man-pages project.  A  description  of  the  project,  and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.