you call fstat on the opened file descriptor and compare device IDs and inodes, as was done in the referenced OpenBSD patch from -96: http://cvsweb.openbsd.org/

you call fstat on the opened file descriptor and compare device IDs and inodes, as was done in the referenced OpenBSD patch from -96: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/libexec/mail.local/mail.local.c.diff?r1=1.1&r2=1.2&f=h http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/libexec/mail.lo... EDIT: corrected year