/*
 * Q_QUOTAON - set up a quota file for a particular filesystem.
 */
int
quotaon(struct thread *td, struct mount *mp, int type, void *fname)
{
	struct ufsmount *ump;
	struct vnode *vp, **vpp;
	struct vnode *mvp;
	struct dquot *dq;
	int error, flags;
	struct nameidata nd;

	error = priv_check(td, PRIV_UFS_QUOTAON);
	if (error != 0) {
		vfs_unbusy(mp);
		return (error);
	}

	if ((mp->mnt_flag & MNT_RDONLY) != 0) {
		vfs_unbusy(mp);
		return (EROFS);
	}

	ump = VFSTOUFS(mp);
	dq = NODQUOT;

	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fname, td);
	flags = FREAD | FWRITE;
	vfs_ref(mp);
	vfs_unbusy(mp);
	error = vn_open(&nd, &flags, 0, NULL);
	if (error != 0) {
		vfs_rel(mp);
		return (error);
	}
	NDFREE(&nd, NDF_ONLY_PNBUF);
	vp = nd.ni_vp;
	error = vfs_busy(mp, MBF_NOWAIT);
	vfs_rel(mp);
	if (error == 0) {
		if (vp->v_type != VREG) {
			error = EACCES;
			vfs_unbusy(mp);
		}
	}
	if (error != 0) {
		VOP_UNLOCK(vp, 0);
		(void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
		return (error);
	}

	UFS_LOCK(ump);
	if ((ump->um_qflags[type] & (QTF_OPENING|QTF_CLOSING)) != 0) {
		UFS_UNLOCK(ump);
		VOP_UNLOCK(vp, 0);
		(void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
		vfs_unbusy(mp);
		return (EALREADY);
	}
	ump->um_qflags[type] |= QTF_OPENING|QTF_CLOSING;
	UFS_UNLOCK(ump);
	if ((error = dqopen(vp, ump, type)) != 0) {
		VOP_UNLOCK(vp, 0);
		UFS_LOCK(ump);
		ump->um_qflags[type] &= ~(QTF_OPENING|QTF_CLOSING);
		UFS_UNLOCK(ump);
		(void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
		vfs_unbusy(mp);
		return (error);
	}
	VOP_UNLOCK(vp, 0);
	MNT_ILOCK(mp);
	mp->mnt_flag |= MNT_QUOTA;
	MNT_IUNLOCK(mp);

	vpp = &ump->um_quotas[type];
	if (*vpp != vp)
		quotaoff1(td, mp, type);

	/*
	 * When the directory vnode containing the quota file is
	 * inactivated, due to the shared lookup of the quota file
	 * vput()ing the dvp, the qsyncvp() call for the containing
	 * directory would try to acquire the quota lock exclusive.
	 * At the same time, lookup already locked the quota vnode
	 * shared.  Mark the quota vnode lock as allowing recursion
	 * and automatically converting shared locks to exclusive.
	 *
	 * Also mark quota vnode as system.
	 */
	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
	vp->v_vflag |= VV_SYSTEM;
	VN_LOCK_AREC(vp);
	VN_LOCK_DSHARE(vp);
	VOP_UNLOCK(vp, 0);
	*vpp = vp;
	/*
	 * Save the credential of the process that turned on quotas.
	 * Set up the time limits for this quota.
//.........这里部分代码省略.........

/* ARGSUSED */
int
sys_auditctl(struct thread *td, struct auditctl_args *uap)
{
    struct nameidata nd;
    struct ucred *cred;
    struct vnode *vp;
    int error = 0;
    int flags;

    if (jailed(td->td_ucred))
        return (ENOSYS);
    error = priv_check(td, PRIV_AUDIT_CONTROL);
    if (error)
        return (error);

    vp = NULL;
    cred = NULL;

    /*
     * If a path is specified, open the replacement vnode, perform
     * validity checks, and grab another reference to the current
     * credential.
     *
     * On Darwin, a NULL path argument is also used to disable audit.
     */
    if (uap->path == NULL)
        return (EINVAL);

    NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1,
           UIO_USERSPACE, uap->path, td);
    flags = AUDIT_OPEN_FLAGS;
    error = vn_open(&nd, &flags, 0, NULL);
    if (error)
        return (error);
    vp = nd.ni_vp;
#ifdef MAC
    error = mac_system_check_auditctl(td->td_ucred, vp);
    VOP_UNLOCK(vp, 0);
    if (error) {
        vn_close(vp, AUDIT_CLOSE_FLAGS, td->td_ucred, td);
        return (error);
    }
#else
    VOP_UNLOCK(vp, 0);
#endif
    NDFREE(&nd, NDF_ONLY_PNBUF);
    if (vp->v_type != VREG) {
        vn_close(vp, AUDIT_CLOSE_FLAGS, td->td_ucred, td);
        return (EINVAL);
    }
    cred = td->td_ucred;
    crhold(cred);

    /*
     * XXXAUDIT: Should audit_suspended actually be cleared by
     * audit_worker?
     */
    audit_suspended = 0;

    audit_rotate_vnode(cred, vp);

    return (error);
}

//.........这里部分代码省略.........
			    td->td_ucred, td);
			if (error)
				error = priv_check(td, PRIV_VFS_MOUNT_PERM);
			if (error) {
				VOP_UNLOCK(devvp, 0);
				return (error);
			}
			VOP_UNLOCK(devvp, 0);
			DROP_GIANT();
			g_topology_lock();
			error = g_access(ump->um_cp, 0, 1, 0);
			g_topology_unlock();
			PICKUP_GIANT();
			if (error)
				return (error);

			if ((fs->e2fs->e2fs_state & E2FS_ISCLEAN) == 0 ||
			    (fs->e2fs->e2fs_state & E2FS_ERRORS)) {
				if (mp->mnt_flag & MNT_FORCE) {
					printf(
"WARNING: %s was not properly dismounted\n", fs->e2fs_fsmnt);
				} else {
					printf(
"WARNING: R/W mount of %s denied.  Filesystem is not clean - run fsck\n",
					    fs->e2fs_fsmnt);
					return (EPERM);
				}
			}
			fs->e2fs->e2fs_state &= ~E2FS_ISCLEAN;
			(void)ext2_cgupdate(ump, MNT_WAIT);
			fs->e2fs_ronly = 0;
			MNT_ILOCK(mp);
			mp->mnt_flag &= ~MNT_RDONLY;
			MNT_IUNLOCK(mp);
		}
		if (vfs_flagopt(opts, "export", NULL, 0)) {
			/* Process export requests in vfs_mount.c. */
			return (error);
		}
	}

	/*
	 * Not an update, or updating the name: look up the name
	 * and verify that it refers to a sensible disk device.
	 */
	if (fspec == NULL)
		return (EINVAL);
	NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, fspec, td);
	if ((error = namei(ndp)) != 0)
		return (error);
	NDFREE(ndp, NDF_ONLY_PNBUF);
	devvp = ndp->ni_vp;

	if (!vn_isdisk(devvp, &error)) {
		vput(devvp);
		return (error);
	}

	/*
	 * If mount by non-root, then verify that user has necessary
	 * permissions on the device.
	 *
	 * XXXRW: VOP_ACCESS() enough?
	 */
	accmode = VREAD;
	if ((mp->mnt_flag & MNT_RDONLY) == 0)
		accmode |= VWRITE;
	error = VOP_ACCESS(devvp, accmode, td->td_ucred, td);
	if (error)
		error = priv_check(td, PRIV_VFS_MOUNT_PERM);
	if (error) {
		vput(devvp);
		return (error);
	}

	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
		error = ext2_mountfs(devvp, mp);
	} else {
		if (devvp != ump->um_devvp) {
			vput(devvp);
			return (EINVAL);	/* needs translation */
		} else
			vput(devvp);
	}
	if (error) {
		vrele(devvp);
		return (error);
	}
	ump = VFSTOEXT2(mp);
	fs = ump->um_e2fs;

	/*
	 * Note that this strncpy() is ok because of a check at the start
	 * of ext2_mount().
	 */
	strncpy(fs->e2fs_fsmnt, path, MAXMNTLEN);
	fs->e2fs_fsmnt[MAXMNTLEN - 1] = '\0';
	vfs_mountedfrom(mp, fspec);
	return (0);
}

/* ARGSUSED */
int
compat_43_sys_lstat(struct lwp *l, const struct compat_43_sys_lstat_args *uap, register_t *retval)
{
	/* {
		syscallarg(char *) path;
		syscallarg(struct ostat *) ub;
	} */
	struct vnode *vp, *dvp;
	struct stat sb, sb1;
	struct stat43 osb;
	int error;
	struct pathbuf *pb;
	struct nameidata nd;
	int ndflags;

	error = pathbuf_copyin(SCARG(uap, path), &pb);
	if (error) {
		return error;
	}

	ndflags = NOFOLLOW | LOCKLEAF | LOCKPARENT | TRYEMULROOT;
again:
	NDINIT(&nd, LOOKUP, ndflags, pb);
	if ((error = namei(&nd))) {
		if (error == EISDIR && (ndflags & LOCKPARENT) != 0) {
			/*
			 * Should only happen on '/'. Retry without LOCKPARENT;
			 * this is safe since the vnode won't be a VLNK.
			 */
			ndflags &= ~LOCKPARENT;
			goto again;
		}
		pathbuf_destroy(pb);
		return (error);
	}
	/*
	 * For symbolic links, always return the attributes of its
	 * containing directory, except for mode, size, and links.
	 */
	vp = nd.ni_vp;
	dvp = nd.ni_dvp;
	pathbuf_destroy(pb);
	if (vp->v_type != VLNK) {
		if ((ndflags & LOCKPARENT) != 0) {
			if (dvp == vp)
				vrele(dvp);
			else
				vput(dvp);
		}
		error = vn_stat(vp, &sb);
		vput(vp);
		if (error)
			return (error);
	} else {
		error = vn_stat(dvp, &sb);
		vput(dvp);
		if (error) {
			vput(vp);
			return (error);
		}
		error = vn_stat(vp, &sb1);
		vput(vp);
		if (error)
			return (error);
		sb.st_mode &= ~S_IFDIR;
		sb.st_mode |= S_IFLNK;
		sb.st_nlink = sb1.st_nlink;
		sb.st_size = sb1.st_size;
		sb.st_blocks = sb1.st_blocks;
	}
	cvtstat(&sb, &osb);
	error = copyout((void *)&osb, (void *)SCARG(uap, ub), sizeof (osb));
	return (error);
}

static int
link_elf_load_file(linker_class_t cls, const char *filename,
    linker_file_t *result)
{
	struct nameidata nd;
	struct thread *td = curthread;	/* XXX */
	Elf_Ehdr *hdr;
	Elf_Shdr *shdr;
	Elf_Sym *es;
	int nbytes, i, j;
	vm_offset_t mapbase;
	size_t mapsize;
	int error = 0;
	ssize_t resid;
	int flags;
	elf_file_t ef;
	linker_file_t lf;
	int symtabindex;
	int symstrindex;
	int shstrindex;
	int nsym;
	int pb, rl, ra;
	int alignmask;

	shdr = NULL;
	lf = NULL;
	mapsize = 0;
	hdr = NULL;

	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
	flags = FREAD;
	error = vn_open(&nd, &flags, 0, NULL);
	if (error)
		return error;
	NDFREE(&nd, NDF_ONLY_PNBUF);
	if (nd.ni_vp->v_type != VREG) {
		error = ENOEXEC;
		goto out;
	}
#ifdef MAC
	error = mac_kld_check_load(td->td_ucred, nd.ni_vp);
	if (error) {
		goto out;
	}
#endif

	/* Read the elf header from the file. */
	hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
	error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0,
	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
	    &resid, td);
	if (error)
		goto out;
	if (resid != 0){
		error = ENOEXEC;
		goto out;
	}

	if (!IS_ELF(*hdr)) {
		error = ENOEXEC;
		goto out;
	}

	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
	    || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
		link_elf_error(filename, "Unsupported file layout");
		error = ENOEXEC;
		goto out;
	}
	if (hdr->e_ident[EI_VERSION] != EV_CURRENT
	    || hdr->e_version != EV_CURRENT) {
		link_elf_error(filename, "Unsupported file version");
		error = ENOEXEC;
		goto out;
	}
	if (hdr->e_type != ET_REL) {
		error = ENOSYS;
		goto out;
	}
	if (hdr->e_machine != ELF_TARG_MACH) {
		link_elf_error(filename, "Unsupported machine");
		error = ENOEXEC;
		goto out;
	}

	lf = linker_make_file(filename, &link_elf_class);
	if (!lf) {
		error = ENOMEM;
		goto out;
	}
	ef = (elf_file_t) lf;
	ef->nprogtab = 0;
	ef->e_shdr = 0;
	ef->nreltab = 0;
	ef->nrelatab = 0;

	/* Allocate and read in the section header */
	nbytes = hdr->e_shnum * hdr->e_shentsize;
	if (nbytes == 0 || hdr->e_shoff == 0 ||
	    hdr->e_shentsize != sizeof(Elf_Shdr)) {
//.........这里部分代码省略.........

/*
 * Mount null layer
 */
static int
nullfs_mount(struct mount *mp)
{
	int error = 0;
	struct vnode *lowerrootvp, *vp;
	struct vnode *nullm_rootvp;
	struct null_mount *xmp;
	struct thread *td = curthread;
	char *target;
	int isvnunlocked = 0, len;
	struct nameidata nd, *ndp = &nd;

	NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);

	if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_NULLFS))
		return (EPERM);

	if (mp->mnt_flag & MNT_ROOTFS)
		return (EOPNOTSUPP);
	/*
	 * Update is a no-op
	 */
	if (mp->mnt_flag & MNT_UPDATE) {
		/*
		 * Only support update mounts for NFS export.
		 */
		if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
			return (0);
		else
			return (EOPNOTSUPP);
	}

	/*
	 * Get argument
	 */
	error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
	if (error || target[len - 1] != '\0')
		return (EINVAL);

	/*
	 * Unlock lower node to avoid possible deadlock.
	 */
	if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) &&
	    VOP_ISLOCKED(mp->mnt_vnodecovered) == LK_EXCLUSIVE) {
		VOP_UNLOCK(mp->mnt_vnodecovered, 0);
		isvnunlocked = 1;
	}
	/*
	 * Find lower node
	 */
	NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread);
	error = namei(ndp);
	/*
	 * Re-lock vnode.
	 */
	if (isvnunlocked)
		vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY);

	if (error)
		return (error);
	NDFREE(ndp, NDF_ONLY_PNBUF);

	/*
	 * Sanity check on lower vnode
	 */
	lowerrootvp = ndp->ni_vp;

	/*
	 * Check multi null mount to avoid `lock against myself' panic.
	 */
	if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
		NULLFSDEBUG("nullfs_mount: multi null mount?\n");
		vput(lowerrootvp);
		return (EDEADLK);
	}

	xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
				M_NULLFSMNT, M_WAITOK);	/* XXX */

	/*
	 * Save reference to underlying FS
	 */
	xmp->nullm_vfs = lowerrootvp->v_mount;

	/*
	 * Save reference.  Each mount also holds
	 * a reference on the root vnode.
	 */
	error = null_nodeget(mp, lowerrootvp, &vp);
	/*
	 * Make sure the node alias worked
	 */
	if (error) {
		free(xmp, M_NULLFSMNT);
		return (error);
	}

//.........这里部分代码省略.........

static int
udf_mount(struct mount *mp)
{
	struct vnode *devvp;	/* vnode of the mount device */
	struct thread *td;
	struct udf_mnt *imp = 0;
	struct vfsoptlist *opts;
	char *fspec, *cs_disk, *cs_local;
	int error, len, *udf_flags;
	struct nameidata nd, *ndp = &nd;

	td = curthread;
	opts = mp->mnt_optnew;

	/*
	 * Unconditionally mount as read-only.
	 */
	MNT_ILOCK(mp);
	mp->mnt_flag |= MNT_RDONLY;
	MNT_IUNLOCK(mp);

	/*
	 * No root filesystem support.  Probably not a big deal, since the
	 * bootloader doesn't understand UDF.
	 */
	if (mp->mnt_flag & MNT_ROOTFS)
		return (ENOTSUP);

	fspec = NULL;
	error = vfs_getopt(opts, "from", (void **)&fspec, &len);
	if (!error && fspec[len - 1] != '\0')
		return (EINVAL);

	if (mp->mnt_flag & MNT_UPDATE) {
		return (0);
	}

	/* Check that the mount device exists */
	if (fspec == NULL)
		return (EINVAL);
	NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, fspec, td);
	if ((error = namei(ndp)))
		return (error);
	NDFREE(ndp, NDF_ONLY_PNBUF);
	devvp = ndp->ni_vp;

	if (vn_isdisk(devvp, &error) == 0) {
		vput(devvp);
		return (error);
	}

	/* Check the access rights on the mount device */
	error = VOP_ACCESS(devvp, VREAD, td->td_ucred, td);
	if (error)
		error = priv_check(td, PRIV_VFS_MOUNT_PERM);
	if (error) {
		vput(devvp);
		return (error);
	}

	if ((error = udf_mountfs(devvp, mp))) {
		vrele(devvp);
		return (error);
	}

	imp = VFSTOUDFFS(mp);

	udf_flags = NULL;
	error = vfs_getopt(opts, "flags", (void **)&udf_flags, &len);
	if (error || len != sizeof(int))
		return (EINVAL);
	imp->im_flags = *udf_flags;

	if (imp->im_flags & UDFMNT_KICONV && udf_iconv) {
		cs_disk = NULL;
		error = vfs_getopt(opts, "cs_disk", (void **)&cs_disk, &len);
		if (!error && cs_disk[len - 1] != '\0')
			return (EINVAL);
		cs_local = NULL;
		error = vfs_getopt(opts, "cs_local", (void **)&cs_local, &len);
		if (!error && cs_local[len - 1] != '\0')
			return (EINVAL);
		udf_iconv->open(cs_local, cs_disk, &imp->im_d2l);
#if 0
		udf_iconv->open(cs_disk, cs_local, &imp->im_l2d);
#endif
	}

	vfs_mountedfrom(mp, fspec);
	return 0;
};

/* ARGSUSED */
int
vndioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
{
	int unit = DISKUNIT(dev);
	struct disklabel *lp;
	struct vnd_softc *sc;
	struct vnd_ioctl *vio;
	struct vnd_user *vnu;
	struct vattr vattr;
	struct nameidata nd;
	int error, part, pmask;

	DNPRINTF(VDB_FOLLOW, "vndioctl(%x, %lx, %p, %x, %p): unit %d\n",
	    dev, cmd, addr, flag, p, unit);

	error = suser(p, 0);
	if (error)
		return (error);
	if (unit >= numvnd)
		return (ENXIO);

	sc = &vnd_softc[unit];
	vio = (struct vnd_ioctl *)addr;
	switch (cmd) {

	case VNDIOCSET:
		if (sc->sc_flags & VNF_INITED)
			return (EBUSY);

		/* Geometry eventually has to fit into label fields */
		if (vio->vnd_secsize > UINT_MAX ||
		    vio->vnd_ntracks > UINT_MAX ||
		    vio->vnd_nsectors > UINT_MAX)
			return (EINVAL);

		if ((error = disk_lock(&sc->sc_dk)) != 0)
			return (error);

		if ((error = copyinstr(vio->vnd_file, sc->sc_file,
		    sizeof(sc->sc_file), NULL))) {
			disk_unlock(&sc->sc_dk);
			return (error);
		}

		/* Set geometry for device. */
		sc->sc_secsize = vio->vnd_secsize;
		sc->sc_ntracks = vio->vnd_ntracks;
		sc->sc_nsectors = vio->vnd_nsectors;

		/*
		 * Open for read and write first. This lets vn_open() weed out
		 * directories, sockets, etc. so we don't have to worry about
		 * them.
		 */
		NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vnd_file, p);
		sc->sc_flags &= ~VNF_READONLY;
		error = vn_open(&nd, FREAD|FWRITE, 0);
		if (error == EROFS) {
			sc->sc_flags |= VNF_READONLY;
			error = vn_open(&nd, FREAD, 0);
		}
		if (error) {
			disk_unlock(&sc->sc_dk);
			return (error);
		}

		if (nd.ni_vp->v_type == VBLK)
			sc->sc_size = vndbdevsize(nd.ni_vp, p);
		else {
			error = VOP_GETATTR(nd.ni_vp, &vattr, p->p_ucred, p);
			if (error) {
				VOP_UNLOCK(nd.ni_vp, 0, p);
				vn_close(nd.ni_vp, VNDRW(sc), p->p_ucred, p);
				disk_unlock(&sc->sc_dk);
				return (error);
			}
			sc->sc_size = vattr.va_size / sc->sc_secsize;
		}
		VOP_UNLOCK(nd.ni_vp, 0, p);
		sc->sc_vp = nd.ni_vp;
		if ((error = vndsetcred(sc, p->p_ucred)) != 0) {
			(void) vn_close(nd.ni_vp, VNDRW(sc), p->p_ucred, p);
			disk_unlock(&sc->sc_dk);
			return (error);
		}

		if (vio->vnd_keylen > 0) {
			char key[BLF_MAXUTILIZED];

			if (vio->vnd_keylen > sizeof(key))
				vio->vnd_keylen = sizeof(key);

			if ((error = copyin(vio->vnd_key, key,
			    vio->vnd_keylen)) != 0) {
				(void) vn_close(nd.ni_vp, VNDRW(sc),
				    p->p_ucred, p);
				disk_unlock(&sc->sc_dk);
				return (error);
			}
//.........这里部分代码省略.........

//.........这里部分代码省略.........
			mp->mnt_flag |= MNT_RDONLY;
			MNT_IUNLOCK(mp);
		} else if ((pmp->pm_flags & MSDOSFSMNT_RONLY) &&
		    !vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
			/*
			 * If upgrade to read-write by non-root, then verify
			 * that user has necessary permissions on the device.
			 */
			devvp = pmp->pm_devvp;
			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
			error = VOP_ACCESS(devvp, VREAD | VWRITE,
			    td->td_ucred, td);
			if (error)
				error = priv_check(td, PRIV_VFS_MOUNT_PERM);
			if (error) {
				VOP_UNLOCK(devvp, 0);
				return (error);
			}
			VOP_UNLOCK(devvp, 0);
			DROP_GIANT();
			g_topology_lock();
			error = g_access(pmp->pm_cp, 0, 1, 0);
			g_topology_unlock();
			PICKUP_GIANT();
			if (error)
				return (error);

			pmp->pm_fmod = 1;
			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
			MNT_ILOCK(mp);
			mp->mnt_flag &= ~MNT_RDONLY;
			MNT_IUNLOCK(mp);

			/* Now that the volume is modifiable, mark it dirty. */
			error = markvoldirty(pmp, 1);
			if (error)
				return (error); 
		}
	}
	/*
	 * Not an update, or updating the name: look up the name
	 * and verify that it refers to a sensible disk device.
	 */
	if (vfs_getopt(mp->mnt_optnew, "from", (void **)&from, NULL))
		return (EINVAL);
	NDINIT(&ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, from, td);
	error = namei(&ndp);
	if (error)
		return (error);
	devvp = ndp.ni_vp;
	NDFREE(&ndp, NDF_ONLY_PNBUF);

	if (!vn_isdisk(devvp, &error)) {
		vput(devvp);
		return (error);
	}
	/*
	 * If mount by non-root, then verify that user has necessary
	 * permissions on the device.
	 */
	accmode = VREAD;
	if ((mp->mnt_flag & MNT_RDONLY) == 0)
		accmode |= VWRITE;
	error = VOP_ACCESS(devvp, accmode, td->td_ucred, td);
	if (error)
		error = priv_check(td, PRIV_VFS_MOUNT_PERM);
	if (error) {
		vput(devvp);
		return (error);
	}
	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
		error = mountmsdosfs(devvp, mp);
#ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
		pmp = VFSTOMSDOSFS(mp);
#endif
	} else {
		vput(devvp);
		if (devvp != pmp->pm_devvp)
			return (EINVAL);	/* XXX needs translation */
	}
	if (error) {
		vrele(devvp);
		return (error);
	}

	error = update_mp(mp, td);
	if (error) {
		if ((mp->mnt_flag & MNT_UPDATE) == 0)
			msdosfs_unmount(mp, MNT_FORCE);
		return error;
	}

	if (devvp->v_type == VCHR && devvp->v_rdev != NULL)
		devvp->v_rdev->si_mountpt = mp;
	vfs_mountedfrom(mp, from);
#ifdef MSDOSFS_DEBUG
	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
#endif
	return (0);
}

//.........这里部分代码省略.........
	 */
	lastslash = strrchr(name, '/');
	if (!lastslash) {
		vp = p->p_cwdi->cwdi_cdir;
		if (vp->v_mount == NULL ||
		    (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0)
			error = EPERM;
	}

	mutex_exit(p->p_lock);
	mutex_exit(proc_lock);
	if (error)
		goto done;

	/*
	 * On a complex filename, see if the filesystem allow us to write
	 * core dumps there.
	 *
	 * XXX: We should have an API that avoids double lookups
	 */
	if (lastslash) {
		char c[2];

		if (lastslash - name >= MAXPATHLEN - 2) {
			error = EPERM;
			goto done;
		}

		c[0] = lastslash[1];
		c[1] = lastslash[2];
		lastslash[1] = '.';
		lastslash[2] = '\0';
		error = namei_simple_kernel(name, NSM_FOLLOW_NOEMULROOT, &vp);
		if (error)
			goto done;
		if (vp->v_mount == NULL ||
		    (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0)
			error = EPERM;
		vrele(vp);
		if (error)
			goto done;
		lastslash[1] = c[0];
		lastslash[2] = c[1];
	}

	pb = pathbuf_create(name);
	if (pb == NULL) {
		error = ENOMEM;
		goto done;
	}
	NDINIT(&nd, LOOKUP, NOFOLLOW, pb);
	if ((error = vn_open(&nd, O_CREAT | O_NOFOLLOW | FWRITE,
	    S_IRUSR | S_IWUSR)) != 0) {
		pathbuf_destroy(pb);
		goto done;
	}
	vp = nd.ni_vp;
	pathbuf_destroy(pb);

	/*
	 * Don't dump to:
	 * 	- non-regular files
	 * 	- files with links
	 * 	- files we don't own
	 */
	if (vp->v_type != VREG ||
	    VOP_GETATTR(vp, &vattr, cred) || vattr.va_nlink != 1 ||
	    vattr.va_uid != kauth_cred_geteuid(cred)) {
		error = EACCES;
		goto out;
	}
	vattr_null(&vattr);
	vattr.va_size = 0;

	if ((p->p_flag & PK_SUGID) && security_setidcore_dump) {
		vattr.va_uid = security_setidcore_owner;
		vattr.va_gid = security_setidcore_group;
		vattr.va_mode = security_setidcore_mode;
	}

	VOP_SETATTR(vp, &vattr, cred);
	p->p_acflag |= ACORE;

	io.io_lwp = l;
	io.io_vp = vp;
	io.io_cred = cred;
	io.io_offset = 0;

	/* Now dump the actual core file. */
	error = (*p->p_execsw->es_coredump)(l, &io);
 out:
	VOP_UNLOCK(vp);
	error1 = vn_close(vp, FWRITE, cred);
	if (error == 0)
		error = error1;
done:
	if (name != NULL)
		PNBUF_PUT(name);
	return error;
}

//.........这里部分代码省略.........
						      p->p_ucred);
				if (error)
					goto error_1;
			}
			fs->fs_contigdirs = malloc((u_long)fs->fs_ncg,
			     M_UFSMNT, M_WAITOK|M_ZERO);

			ronly = 0;
		}
		if (args.fspec == NULL) {
			/*
			 * Process export requests.
			 */
			error = vfs_export(mp, &ump->um_export, 
			    &args.export_info);
			if (error)
				goto error_1;
			else
				goto success;
		}
	}

	/*
	 * Not an update, or updating the name: look up the name
	 * and verify that it refers to a sensible block device.
	 */
	error = copyinstr(args.fspec, fspec, sizeof(fspec), NULL);
	if (error)
		goto error_1;

	if (disk_map(fspec, fname, MNAMELEN, DM_OPENBLCK) == -1)
		memcpy(fname, fspec, sizeof(fname));

	NDINIT(ndp, LOOKUP, FOLLOW, UIO_SYSSPACE, fname, p);
	if ((error = namei(ndp)) != 0)
		goto error_1;

	devvp = ndp->ni_vp;

	if (devvp->v_type != VBLK) {
		error = ENOTBLK;
		goto error_2;
	}

	if (major(devvp->v_rdev) >= nblkdev) {
		error = ENXIO;
		goto error_2;
	}

	/*
	 * If mount by non-root, then verify that user has necessary
	 * permissions on the device.
	 */
	if (suser(p, 0)) {
		accessmode = VREAD;
		if ((mp->mnt_flag & MNT_RDONLY) == 0)
			accessmode |= VWRITE;
		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
		error = VOP_ACCESS(devvp, accessmode, p->p_ucred, p);
		VOP_UNLOCK(devvp, 0, p);
		if (error)
			goto error_2;
	}

	if (mp->mnt_flag & MNT_UPDATE) {
		/*

static int
cd9660_mount(struct mount *mp)
{
	struct vnode *devvp;
	struct thread *td;
	char *fspec;
	int error;
	accmode_t accmode;
	struct nameidata ndp;
	struct iso_mnt *imp = NULL;

	td = curthread;

	/*
	 * Unconditionally mount as read-only.
	 */
	MNT_ILOCK(mp);
	mp->mnt_flag |= MNT_RDONLY;
	MNT_IUNLOCK(mp);

	fspec = vfs_getopts(mp->mnt_optnew, "from", &error);
	if (error)
		return (error);

	imp = VFSTOISOFS(mp);

	if (mp->mnt_flag & MNT_UPDATE) {
		if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
			return (0);
	}
	/*
	 * Not an update, or updating the name: look up the name
	 * and verify that it refers to a sensible block device.
	 */
	NDINIT(&ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, fspec, td);
	if ((error = namei(&ndp)))
		return (error);
	NDFREE(&ndp, NDF_ONLY_PNBUF);
	devvp = ndp.ni_vp;

	if (!vn_isdisk(devvp, &error)) {
		vput(devvp);
		return (error);
	}

	/*
	 * Verify that user has necessary permissions on the device,
	 * or has superuser abilities
	 */
	accmode = VREAD;
	error = VOP_ACCESS(devvp, accmode, td->td_ucred, td);
	if (error)
		error = priv_check(td, PRIV_VFS_MOUNT_PERM);
	if (error) {
		vput(devvp);
		return (error);
	}

	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
		error = iso_mountfs(devvp, mp);
		if (error)
			vrele(devvp);
	} else {
		if (devvp != imp->im_devvp)
			error = EINVAL;	/* needs translation */
		vput(devvp);
	}
	if (error)
		return (error);
	vfs_mountedfrom(mp, fspec);
	return (0);
}

VMBlockVFSMount(struct mount *mp,        // IN: mount(2) parameters
                struct thread *td)       // IN: caller's thread context
#endif
{
   struct VMBlockMount *xmp;
   struct nameidata nd, *ndp = &nd;
   struct vnode *lowerrootvp, *vp;
   char *target;
   char *pathname;
   int len, error = 0;

   VMBLOCKDEBUG("VMBlockVFSMount(mp = %p)\n", (void *)mp);

   /*
    * TODO:  Strip out extraneous export & other misc cruft.
    */

   /*
    * Disallow the following:
    *   1.  Mounting over the system root.
    *   2.  Mount updates/remounts.  (Reconsider for rw->ro, ro->rw?)
    *   3.  Mounting VMBlock on top of a VMBlock.
    */
   if ((mp->mnt_flag & MNT_ROOTFS) ||
       (mp->mnt_flag & MNT_UPDATE) ||
       (mp->mnt_vnodecovered->v_op == &VMBlockVnodeOps)) {
      return EOPNOTSUPP;
   }

   /*
    * XXX Should only be unlocked if mnt_flag & MNT_UPDATE.
    */
   ASSERT_VOP_UNLOCKED(mp->mnt_vnodecovered, "Covered vnode already locked!");

   /*
    * Look up path to lower layer (VMBlock source / DnD staging area).
    * (E.g., in the command "mount /tmp/VMwareDnD /var/run/vmblock",
    * /tmp/VMwareDnD is the staging area.)
    */
   error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
   if (error || target[len - 1] != '\0') {
      return EINVAL;
   }

   pathname = uma_zalloc(VMBlockPathnameZone, M_WAITOK);
   if (pathname == NULL) {
      return ENOMEM;
   }

   if (strlcpy(pathname, target, MAXPATHLEN) >= MAXPATHLEN) {
      uma_zfree(VMBlockPathnameZone, pathname);
      return ENAMETOOLONG;
   }

   /*
    * Find lower node and lock if not already locked.
    */

   NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, compat_td);
   error = namei(ndp);
   if (error) {
      NDFREE(ndp, 0);
      uma_zfree(VMBlockPathnameZone, pathname);
      return error;
   }
   NDFREE(ndp, NDF_ONLY_PNBUF);

   /*
    * Check multi VMBlock mount to avoid `lock against myself' panic.
    */
   lowerrootvp = ndp->ni_vp;
   if (lowerrootvp == VPTOVMB(mp->mnt_vnodecovered)->lowerVnode) {
      VMBLOCKDEBUG("VMBlockVFSMount: multi vmblock mount?\n");
      vput(lowerrootvp);
      uma_zfree(VMBlockPathnameZone, pathname);
      return EDEADLK;
   }

   xmp = malloc(sizeof *xmp, M_VMBLOCKFSMNT, M_WAITOK);

   /*
    * Record pointer (mountVFS) to the staging area's file system.  Follow up
    * by grabbing a VMBlockNode for our layer's root.
    */
   xmp->mountVFS = lowerrootvp->v_mount;
   error = VMBlockNodeGet(mp, lowerrootvp, &vp, pathname);

   /*
    * Make sure the node alias worked
    */
   if (error) {
      COMPAT_VOP_UNLOCK(vp, 0, compat_td);
      vrele(lowerrootvp);
      free(xmp, M_VMBLOCKFSMNT);   /* XXX */
      uma_zfree(VMBlockPathnameZone, pathname);
      return error;
   }

   /*
    * Record a reference to the new filesystem's root vnode & mark it as such.
//.........这里部分代码省略.........

/* ARGSUSED */
int
auditctl(proc_t p, struct auditctl_args *uap, __unused int32_t *retval)
{
	struct nameidata nd;
	kauth_cred_t cred;
	struct vnode *vp;
	int error = 0;

	error = suser(kauth_cred_get(), &p->p_acflag);
	if (error)
		return (error);

	vp = NULL;
	cred = NULL;

	/*
	 * If a path is specified, open the replacement vnode, perform
	 * validity checks, and grab another reference to the current
	 * credential.
	 *
	 * XXX Changes API slightly.  NULL path no longer disables audit but
	 * returns EINVAL.
	 */
	if (uap->path == USER_ADDR_NULL)
		return (EINVAL);

	NDINIT(&nd, LOOKUP, OP_OPEN, FOLLOW | LOCKLEAF | AUDITVNPATH1,
	    (IS_64BIT_PROCESS(p) ? UIO_USERSPACE64 :
	    UIO_USERSPACE32), uap->path, vfs_context_current());
	error = vn_open(&nd, AUDIT_OPEN_FLAGS, 0);
	if (error)
		return (error);
	vp = nd.ni_vp;
#if CONFIG_MACF
	/*
	 * Accessibility of the vnode was determined in vn_open; the
	 * mac_system_check_auditctl should only determine whether that vnode
	 * is appropriate for storing audit data, or that the caller was
	 * permitted to control the auditing system at all.  For example, a
	 * confidentiality policy may want to ensure that audit files are
	 * always high sensitivity.
	 */
	error = mac_system_check_auditctl(kauth_cred_get(), vp);
	if (error) {
		vn_close(vp, AUDIT_CLOSE_FLAGS, vfs_context_current());
		vnode_put(vp);
		return (error);
	}
#endif
	if (vp->v_type != VREG) {
		vn_close(vp, AUDIT_CLOSE_FLAGS, vfs_context_current());
		vnode_put(vp);
		return (EINVAL);
	}
	mtx_lock(&audit_mtx);
	/*
	 * XXXAUDIT: Should audit_suspended actually be cleared by
	 * audit_worker?
	 */
	audit_suspended = 0;
	mtx_unlock(&audit_mtx);

	/*
	 * The following gets unreferenced in audit_rotate_vnode()
	 * after the rotation and it is no longer needed.
	 */
	cred = kauth_cred_get_with_ref();
	audit_rotate_vnode(cred, vp);
	vnode_put(vp);

	return (error);
}

static void
ptyfs_getinfo(struct ptyfsnode *ptyfs, struct lwp *l)
{
	extern struct ptm_pty *ptyfs_save_ptm, ptm_ptyfspty;

	if (ptyfs->ptyfs_type == PTYFSroot) {
		ptyfs->ptyfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|
		    S_IROTH|S_IXOTH;
		goto out;
	} else
		ptyfs->ptyfs_mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|
		    S_IROTH|S_IWOTH;

	if (ptyfs_save_ptm != NULL && ptyfs_save_ptm != &ptm_ptyfspty) {
		int error;
		struct pathbuf *pb;
		struct nameidata nd;
		char ttyname[64];
		kauth_cred_t cred;
		struct vattr va;

		/*
		 * We support traditional ptys, so we copy the info
		 * from the inode
		 */
		if ((error = (*ptyfs_save_ptm->makename)(
			ptyfs_save_ptm, l, ttyname, sizeof(ttyname),
			ptyfs->ptyfs_pty, ptyfs->ptyfs_type == PTYFSpts ? 't'
			: 'p')) != 0)
				goto out;
		pb = pathbuf_create(ttyname);
		if (pb == NULL) {
			error = ENOMEM;
 			goto out;
		}
		NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, pb);
		if ((error = namei(&nd)) != 0) {
			pathbuf_destroy(pb);
			goto out;
		}
		cred = kauth_cred_alloc();
		error = VOP_GETATTR(nd.ni_vp, &va, cred);
		kauth_cred_free(cred);
		VOP_UNLOCK(nd.ni_vp);
		vrele(nd.ni_vp);
		pathbuf_destroy(pb);
		if (error)
			goto out;
		ptyfs->ptyfs_uid = va.va_uid;
		ptyfs->ptyfs_gid = va.va_gid;
		ptyfs->ptyfs_mode = va.va_mode;
		ptyfs->ptyfs_flags = va.va_flags;
		ptyfs->ptyfs_birthtime = va.va_birthtime;
		ptyfs->ptyfs_ctime = va.va_ctime;
		ptyfs->ptyfs_mtime = va.va_mtime;
		ptyfs->ptyfs_atime = va.va_atime;
		return;
	}
out:
	ptyfs->ptyfs_uid = ptyfs->ptyfs_gid = 0;
	ptyfs->ptyfs_status |= PTYFS_CHANGE;
	PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
	ptyfs->ptyfs_birthtime = ptyfs->ptyfs_mtime =
	    ptyfs->ptyfs_atime = ptyfs->ptyfs_ctime;
	ptyfs->ptyfs_flags = 0;
}

static int
vfs_mountroot_shuffle(struct thread *td, struct mount *mpdevfs)
{
	struct nameidata nd;
	struct mount *mporoot, *mpnroot;
	struct vnode *vp, *vporoot, *vpdevfs;
	char *fspath;
	int error;

	mpnroot = TAILQ_NEXT(mpdevfs, mnt_list);

	/* Shuffle the mountlist. */
	mtx_lock(&mountlist_mtx);
	mporoot = TAILQ_FIRST(&mountlist);
	TAILQ_REMOVE(&mountlist, mpdevfs, mnt_list);
	if (mporoot != mpdevfs) {
		TAILQ_REMOVE(&mountlist, mpnroot, mnt_list);
		TAILQ_INSERT_HEAD(&mountlist, mpnroot, mnt_list);
	}
	TAILQ_INSERT_TAIL(&mountlist, mpdevfs, mnt_list);
	mtx_unlock(&mountlist_mtx);

	cache_purgevfs(mporoot);
	if (mporoot != mpdevfs)
		cache_purgevfs(mpdevfs);

	VFS_ROOT(mporoot, LK_EXCLUSIVE, &vporoot);

	VI_LOCK(vporoot);
	vporoot->v_iflag &= ~VI_MOUNT;
	VI_UNLOCK(vporoot);
	vporoot->v_mountedhere = NULL;
	mporoot->mnt_flag &= ~MNT_ROOTFS;
	mporoot->mnt_vnodecovered = NULL;
	vput(vporoot);

	/* Set up the new rootvnode, and purge the cache */
	mpnroot->mnt_vnodecovered = NULL;
	set_rootvnode();
	cache_purgevfs(rootvnode->v_mount);

	if (mporoot != mpdevfs) {
		/* Remount old root under /.mount or /mnt */
		fspath = "/.mount";
		NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
		    fspath, td);
		error = namei(&nd);
		if (error) {
			NDFREE(&nd, NDF_ONLY_PNBUF);
			fspath = "/mnt";
			NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
			    fspath, td);
			error = namei(&nd);
		}
		if (!error) {
			vp = nd.ni_vp;
			error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
			if (!error)
				error = vinvalbuf(vp, V_SAVE, 0, 0);
			if (!error) {
				cache_purge(vp);
				mporoot->mnt_vnodecovered = vp;
				vp->v_mountedhere = mporoot;
				strlcpy(mporoot->mnt_stat.f_mntonname,
				    fspath, MNAMELEN);
				VOP_UNLOCK(vp, 0);
			} else
				vput(vp);
		}
		NDFREE(&nd, NDF_ONLY_PNBUF);

		if (error && bootverbose)
			printf("mountroot: unable to remount previous root "
			    "under /.mount or /mnt (error %d).\n", error);
	}

	/* Remount devfs under /dev */
	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
	error = namei(&nd);
	if (!error) {
		vp = nd.ni_vp;
		error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
		if (!error)
			error = vinvalbuf(vp, V_SAVE, 0, 0);
		if (!error) {
			vpdevfs = mpdevfs->mnt_vnodecovered;
			if (vpdevfs != NULL) {
				cache_purge(vpdevfs);
				vpdevfs->v_mountedhere = NULL;
				vrele(vpdevfs);
			}
			mpdevfs->mnt_vnodecovered = vp;
			vp->v_mountedhere = mpdevfs;
			VOP_UNLOCK(vp, 0);
		} else
			vput(vp);
	}
	if (error && bootverbose)
		printf("mountroot: unable to remount devfs under /dev "
		    "(error %d).\n", error);
//.........这里部分代码省略.........

static int
link_elf_ctf_get(linker_file_t lf, linker_ctf_t *lc)
{
#ifdef DDB_CTF
	Elf_Ehdr *hdr = NULL;
	Elf_Shdr *shdr = NULL;
	caddr_t ctftab = NULL;
	caddr_t raw = NULL;
	caddr_t shstrtab = NULL;
	elf_file_t ef = (elf_file_t) lf;
	int flags;
	int i;
	int nbytes;
	ssize_t resid;
	int vfslocked;
	size_t sz;
	struct nameidata nd;
	struct thread *td = curthread;
	uint8_t ctf_hdr[CTF_HDR_SIZE];
#endif
	int error = 0;

	if (lf == NULL || lc == NULL)
		return (EINVAL);

	/* Set the defaults for no CTF present. That's not a crime! */
	bzero(lc, sizeof(*lc));

#ifdef DDB_CTF
	/*
	 * First check if we've tried to load CTF data previously and the
	 * CTF ELF section wasn't found. We flag that condition by setting
	 * ctfcnt to -1. See below.
	 */
	if (ef->ctfcnt < 0)
		return (EFTYPE);

	/* Now check if we've already loaded the CTF data.. */
	if (ef->ctfcnt > 0) {
		/* We only need to load once. */
		lc->ctftab = ef->ctftab;
		lc->ctfcnt = ef->ctfcnt;
		lc->symtab = ef->ddbsymtab;
		lc->strtab = ef->ddbstrtab;
		lc->strcnt = ef->ddbstrcnt;
		lc->nsym   = ef->ddbsymcnt;
		lc->ctfoffp = (uint32_t **) &ef->ctfoff;
		lc->typoffp = (uint32_t **) &ef->typoff;
		lc->typlenp = &ef->typlen;
		return (0);
	}

	/*
	 * We need to try reading the CTF data. Flag no CTF data present
	 * by default and if we actually succeed in reading it, we'll
	 * update ctfcnt to the number of bytes read.
	 */
	ef->ctfcnt = -1;

	NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, lf->pathname, td);
	flags = FREAD;
	error = vn_open(&nd, &flags, 0, NULL);
	if (error)
		return (error);
	vfslocked = NDHASGIANT(&nd);
	NDFREE(&nd, NDF_ONLY_PNBUF);

	/* Allocate memory for the FLF header. */
	if ((hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK)) == NULL) {
		error = ENOMEM;
		goto out;
	}

	/* Read the ELF header. */
	if ((error = vn_rdwr(UIO_READ, nd.ni_vp, hdr, sizeof(*hdr),
	    0, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid,
	    td)) != 0)
		goto out;

	/* Sanity check. */
	if (!IS_ELF(*hdr)) {
		error = ENOEXEC;
		goto out;
	}

	nbytes = hdr->e_shnum * hdr->e_shentsize;
	if (nbytes == 0 || hdr->e_shoff == 0 ||
	    hdr->e_shentsize != sizeof(Elf_Shdr)) {
		error = ENOEXEC;
		goto out;
	}

	/* Allocate memory for all the section headers */
	if ((shdr = malloc(nbytes, M_LINKER, M_WAITOK)) == NULL) {
		error = ENOMEM;
		goto out;
	}

	/* Read all the section headers */
	if ((error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes,
//.........这里部分代码省略.........

static int
coff_load_file(struct thread *td, char *name)
{
	struct proc *p = td->td_proc;
  	struct vmspace *vmspace = p->p_vmspace;
  	int error;
  	struct nameidata nd;
  	struct vnode *vp;
  	struct vattr attr;
  	struct filehdr *fhdr;
  	struct aouthdr *ahdr;
  	struct scnhdr *scns;
  	char *ptr = 0;
  	int nscns;
  	unsigned long text_offset = 0, text_address = 0, text_size = 0;
  	unsigned long data_offset = 0, data_address = 0, data_size = 0;
  	unsigned long bss_size = 0;
  	int i;

	NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, UIO_SYSSPACE, name, td);

  	error = namei(&nd);
  	if (error)
    		return error;

  	vp = nd.ni_vp;
  	if (vp == NULL)
    		return ENOEXEC;

  	if (vp->v_writecount) {
    		error = ETXTBSY;
    		goto fail;
  	}

  	if ((error = VOP_GETATTR(vp, &attr, td->td_ucred, td)) != 0)
    		goto fail;

  	if ((vp->v_mount->mnt_flag & MNT_NOEXEC)
	    || ((attr.va_mode & 0111) == 0)
	    || (attr.va_type != VREG))
    		goto fail;

  	if (attr.va_size == 0) {
    		error = ENOEXEC;
    		goto fail;
  	}

  	if ((error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td)) != 0)
    		goto fail;

  	if ((error = VOP_OPEN(vp, FREAD, td->td_ucred, td)) != 0)
    		goto fail;

	/*
	 * Lose the lock on the vnode. It's no longer needed, and must not
	 * exist for the pagefault paging to work below.
	 */
	VOP_UNLOCK(vp, 0, td);

  	if ((error = vm_mmap(kernel_map,
			    (vm_offset_t *) &ptr,
			    PAGE_SIZE,
			    VM_PROT_READ,
		       	    VM_PROT_READ,
			    0,
			    (caddr_t) vp,
			    0)) != 0)
		goto un