Function kern_openat

freebsd/kern/vfs_syscalls.c:1094–1225

}

int
kern_openat(struct thread *td, int fd, const char *path, enum uio_seg pathseg,
    int flags, int mode)
{
	struct proc *p = td->td_proc;
	struct filedesc *fdp;
	struct pwddesc *pdp;
	struct file *fp;
	struct vnode *vp;
	struct nameidata nd;
	cap_rights_t rights;
	int cmode, error, indx;

	indx = -1;
	fdp = p->p_fd;
	pdp = p->p_pd;

	AUDIT_ARG_FFLAGS(flags);
	AUDIT_ARG_MODE(mode);
	cap_rights_init_one(&rights, CAP_LOOKUP);
	flags_to_rights(flags, &rights);
	/*
	 * Only one of the O_EXEC, O_RDONLY, O_WRONLY and O_RDWR flags
	 * may be specified.
	 */
	if (flags & O_EXEC) {
		if (flags & O_ACCMODE)
			return (EINVAL);
	} else if ((flags & O_ACCMODE) == O_ACCMODE) {
		return (EINVAL);
	} else {
		flags = FFLAGS(flags);
	}

	/*
	 * Allocate a file structure. The descriptor to reference it
	 * is allocated and used by finstall_refed() below.
	 */
	error = falloc_noinstall(td, &fp);
	if (error != 0)
		return (error);
	/* Set the flags early so the finit in devfs can pick them up. */
	fp->f_flag = flags & FMASK;
	cmode = ((mode & ~pdp->pd_cmask) & ALLPERMS) & ~S_ISTXT;
	NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW | AUDITVNODE1, pathseg, path, fd,
	    &rights, td);
	td->td_dupfd = -1;		/* XXX check for fdopen */
	error = vn_open(&nd, &flags, cmode, fp);
	if (error != 0) {
		/*
		 * If the vn_open replaced the method vector, something
		 * wonderous happened deep below and we just pass it up
		 * pretending we know what we do.
		 */
		if (error == ENXIO && fp->f_ops != &badfileops)
			goto success;

		/*