the systemcall setfsuid is not recommended for use by the Linux manual pages. It was a hack introduced in the Linux kernel 1.X to support multiple users in the userspace NFS Linux implementation due to vulnerability in sending signals across processes.
seteuid is the call to use these days, even though Linux internally uses the fsuid/fsgid for permission verification.
the systemcall
setfsuidis not recommended for use by the Linux manual pages. It was a hack introduced in the Linux kernel 1.X to support multiple users in the userspace NFS Linux implementation due to vulnerability in sending signals across processes.seteuid is the call to use these days, even though Linux internally uses the
fsuid/fsgidfor permission verification.