|SETREUID(2)||System Calls Manual||SETREUID(2)|
LIBRARY¶Standard C Library (libc, -lc)
DESCRIPTION¶The real and effective user IDs of the current process are set according to the arguments. If ruid or euid is -1, the current uid is filled in by the system. Unprivileged users may change the real user ID to the effective user ID and vice-versa; only the super-user may make other changes.
If the real user ID is changed (i.e. ruid is not -1) or the effective user ID is changed to something other than the real user ID, then the saved user ID will be set to the effective user ID.
setreuid() system call has been used
to swap the real and effective user IDs in set-user-ID programs to
temporarily relinquish the set-user-ID value. This purpose is now better
served by the use of the seteuid(2) system call.
When setting the real and effective user IDs to the same value,
setuid() system call is preferred.
setreuid() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.
- The current process is not the super-user and a change other than changing the effective user-id to the real user-id was specified.
SEE ALSO¶getuid(2), issetugid(2), seteuid(2), setuid(2)
setreuid() system call appeared in 4.2BSD.
|February 8, 2001||Linux 4.19.0-13-amd64|