/*

 * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package sun.nio.fs;

import java.nio.file.*;

import java.nio.file.attribute.*;

import java.util.*;

import java.io.IOException;

import static sun.nio.fs.UnixConstants.*;

import static sun.nio.fs.SolarisConstants.*;

import static sun.nio.fs.SolarisNativeDispatcher.*;

/**

 * Solaris implementation of AclFileAttributeView with native support for

 * NFSv4 ACLs on ZFS.

 */

class SolarisAclFileAttributeView

    extends AbstractAclFileAttributeView

{

    private static final Unsafe unsafe = Unsafe.getUnsafe();

    // Maximum number of entries allowed in an ACL

    private static final int MAX_ACL_ENTRIES = 1024;

    /**

     * typedef struct ace {

     *     uid_t        a_who;

     *     uint32_t     a_access_mask;

     *     uint16_t     a_flags;

     *     uint16_t     a_type;

     * } ace_t;

     */

    private static final short SIZEOF_ACE_T     = 12;

    private static final short OFFSETOF_UID     = 0;

    private static final short OFFSETOF_MASK    = 4;

    private static final short OFFSETOF_FLAGS   = 8;

    private static final short OFFSETOF_TYPE    = 10;

    private final UnixPath file;

    private final boolean followLinks;

    SolarisAclFileAttributeView(UnixPath file, boolean followLinks) {

        this.file = file;

        this.followLinks = followLinks;

    }

    /**

     * Permission checks to access file

     */

    private void checkAccess(UnixPath file,

                             boolean checkRead,

                             boolean checkWrite)

    {

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            if (checkRead)

                file.checkRead();

            if (checkWrite)

                file.checkWrite();

            sm.checkPermission(new RuntimePermission("accessUserInformation"));

        }

    }

    /**

     * Encode the ACL to the given buffer

     */

    private static void encode(List<AclEntry> acl, long address) {

        long offset = address;

        for (AclEntry ace: acl) {

            int flags = 0;

            // map UserPrincipal to uid and flags

            UserPrincipal who = ace.principal();

            if (!(who instanceof UnixUserPrincipals.User))

                throw new ProviderMismatchException();

            UnixUserPrincipals.User user = (UnixUserPrincipals.User)who;

            int uid;

            if (user.isSpecial()) {

                uid = -1;

                if (who == UnixUserPrincipals.SPECIAL_OWNER)

                    flags |= ACE_OWNER;

                else if (who == UnixUserPrincipals.SPECIAL_GROUP)

                    flags |= (ACE_GROUP | ACE_IDENTIFIER_GROUP);

                else if (who == UnixUserPrincipals.SPECIAL_EVERYONE)

                    flags |= ACE_EVERYONE;

                else

                    throw new AssertionError("Unable to map special identifier");

            } else {

                if (user instanceof UnixUserPrincipals.Group) {

                    uid = user.gid();

                    flags |= ACE_IDENTIFIER_GROUP;

                } else {

                    uid = user.uid();

                }

            }

            // map ACE type

            int type;

            switch (ace.type()) {

                case ALLOW:

                    type = ACE_ACCESS_ALLOWED_ACE_TYPE;

                    break;

                case DENY:

                    type = ACE_ACCESS_DENIED_ACE_TYPE;

                    break;

                case AUDIT:

                    type = ACE_SYSTEM_AUDIT_ACE_TYPE;

                    break;

                case ALARM:

                    type = ACE_SYSTEM_ALARM_ACE_TYPE;

                    break;

                default:

                    throw new AssertionError("Unable to map ACE type");

            }

            // map permissions

            Set<AclEntryPermission> aceMask = ace.permissions();

            int mask = 0;

            if (aceMask.contains(AclEntryPermission.READ_DATA))

                mask |= ACE_READ_DATA;

            if (aceMask.contains(AclEntryPermission.WRITE_DATA))

                mask |= ACE_WRITE_DATA;

            if (aceMask.contains(AclEntryPermission.APPEND_DATA))

                mask |= ACE_APPEND_DATA;

            if (aceMask.contains(AclEntryPermission.READ_NAMED_ATTRS))

                mask |= ACE_READ_NAMED_ATTRS;

            if (aceMask.contains(AclEntryPermission.WRITE_NAMED_ATTRS))

                mask |= ACE_WRITE_NAMED_ATTRS;

            if (aceMask.contains(AclEntryPermission.EXECUTE))

                mask |= ACE_EXECUTE;

            if (aceMask.contains(AclEntryPermission.DELETE_CHILD))

                mask |= ACE_DELETE_CHILD;

            if (aceMask.contains(AclEntryPermission.READ_ATTRIBUTES))

                mask |= ACE_READ_ATTRIBUTES;

            if (aceMask.contains(AclEntryPermission.WRITE_ATTRIBUTES))

                mask |= ACE_WRITE_ATTRIBUTES;

            if (aceMask.contains(AclEntryPermission.DELETE))

                mask |= ACE_DELETE;

            if (aceMask.contains(AclEntryPermission.READ_ACL))

                mask |= ACE_READ_ACL;

            if (aceMask.contains(AclEntryPermission.WRITE_ACL))

                mask |= ACE_WRITE_ACL;

            if (aceMask.contains(AclEntryPermission.WRITE_OWNER))

                mask |= ACE_WRITE_OWNER;

            if (aceMask.contains(AclEntryPermission.SYNCHRONIZE))

                mask |= ACE_SYNCHRONIZE;

            // FIXME - it would be desirable to know here if the file is a

            // directory or not. Solaris returns EINVAL if an ACE has a directory

            // -only flag and the file is not a directory.

            Set<AclEntryFlag> aceFlags = ace.flags();

            if (aceFlags.contains(AclEntryFlag.FILE_INHERIT))

                flags |= ACE_FILE_INHERIT_ACE;

            if (aceFlags.contains(AclEntryFlag.DIRECTORY_INHERIT))

                flags |= ACE_DIRECTORY_INHERIT_ACE;

            if (aceFlags.contains(AclEntryFlag.NO_PROPAGATE_INHERIT))

                flags |= ACE_NO_PROPAGATE_INHERIT_ACE;

            if (aceFlags.contains(AclEntryFlag.INHERIT_ONLY))

                flags |= ACE_INHERIT_ONLY_ACE;

            unsafe.putInt(offset + OFFSETOF_UID, uid);

            unsafe.putInt(offset + OFFSETOF_MASK, mask);

            unsafe.putShort(offset + OFFSETOF_FLAGS, (short)flags);

            unsafe.putShort(offset + OFFSETOF_TYPE, (short)type);

            offset += SIZEOF_ACE_T;

        }

    }

    /**

     * Decode the buffer, returning an ACL

     */

    private static List<AclEntry> decode(long address, int n) {

        ArrayList<AclEntry> acl = new ArrayList<>(n);

        for (int i=0; i<n; i++) {

            long offset = address + i*SIZEOF_ACE_T;

            int uid = unsafe.getInt(offset + OFFSETOF_UID);

            int mask = unsafe.getInt(offset + OFFSETOF_MASK);

            int flags = (int)unsafe.getShort(offset + OFFSETOF_FLAGS);

            int type = (int)unsafe.getShort(offset + OFFSETOF_TYPE);

            // map uid and flags to UserPrincipal

            UnixUserPrincipals.User who = null;

            if ((flags & ACE_OWNER) > 0) {

                who = UnixUserPrincipals.SPECIAL_OWNER;

            } else if ((flags & ACE_GROUP) > 0) {

                who = UnixUserPrincipals.SPECIAL_GROUP;

            } else if ((flags & ACE_EVERYONE) > 0) {

                who = UnixUserPrincipals.SPECIAL_EVERYONE;

            } else if ((flags & ACE_IDENTIFIER_GROUP) > 0) {

                who = UnixUserPrincipals.fromGid(uid);

            } else {

                who = UnixUserPrincipals.fromUid(uid);

            }

            AclEntryType aceType = null;

            switch (type) {

                case ACE_ACCESS_ALLOWED_ACE_TYPE:

                    aceType = AclEntryType.ALLOW;

                    break;

                case ACE_ACCESS_DENIED_ACE_TYPE:

                    aceType = AclEntryType.DENY;

                    break;

                case ACE_SYSTEM_AUDIT_ACE_TYPE:

                    aceType = AclEntryType.AUDIT;

                    break;

                case ACE_SYSTEM_ALARM_ACE_TYPE:

                    aceType = AclEntryType.ALARM;

                    break;

                default:

                    assert false;

            }

            Set<AclEntryPermission> aceMask = EnumSet.noneOf(AclEntryPermission.class);

            if ((mask & ACE_READ_DATA) > 0)

                aceMask.add(AclEntryPermission.READ_DATA);

            if ((mask & ACE_WRITE_DATA) > 0)

                aceMask.add(AclEntryPermission.WRITE_DATA);

            if ((mask & ACE_APPEND_DATA ) > 0)

                aceMask.add(AclEntryPermission.APPEND_DATA);

            if ((mask & ACE_READ_NAMED_ATTRS) > 0)

                aceMask.add(AclEntryPermission.READ_NAMED_ATTRS);

            if ((mask & ACE_WRITE_NAMED_ATTRS) > 0)

                aceMask.add(AclEntryPermission.WRITE_NAMED_ATTRS);

            if ((mask & ACE_EXECUTE) > 0)

                aceMask.add(AclEntryPermission.EXECUTE);

            if ((mask & ACE_DELETE_CHILD ) > 0)

                aceMask.add(AclEntryPermission.DELETE_CHILD);

            if ((mask & ACE_READ_ATTRIBUTES) > 0)

                aceMask.add(AclEntryPermission.READ_ATTRIBUTES);

            if ((mask & ACE_WRITE_ATTRIBUTES) > 0)

                aceMask.add(AclEntryPermission.WRITE_ATTRIBUTES);

            if ((mask & ACE_DELETE) > 0)

                aceMask.add(AclEntryPermission.DELETE);

            if ((mask & ACE_READ_ACL) > 0)

                aceMask.add(AclEntryPermission.READ_ACL);

            if ((mask & ACE_WRITE_ACL) > 0)

                aceMask.add(AclEntryPermission.WRITE_ACL);

            if ((mask & ACE_WRITE_OWNER) > 0)

                aceMask.add(AclEntryPermission.WRITE_OWNER);

            if ((mask & ACE_SYNCHRONIZE) > 0)

                aceMask.add(AclEntryPermission.SYNCHRONIZE);

            Set<AclEntryFlag> aceFlags = EnumSet.noneOf(AclEntryFlag.class);

            if ((flags & ACE_FILE_INHERIT_ACE) > 0)

                aceFlags.add(AclEntryFlag.FILE_INHERIT);

            if ((flags & ACE_DIRECTORY_INHERIT_ACE) > 0)

                aceFlags.add(AclEntryFlag.DIRECTORY_INHERIT);

            if ((flags & ACE_NO_PROPAGATE_INHERIT_ACE) > 0)

                aceFlags.add(AclEntryFlag.NO_PROPAGATE_INHERIT);

            if ((flags & ACE_INHERIT_ONLY_ACE) > 0)

                aceFlags.add(AclEntryFlag.INHERIT_ONLY);

            // build the ACL entry and add it to the list

            AclEntry ace = AclEntry.newBuilder()

                .setType(aceType)

                .setPrincipal(who)

                .setPermissions(aceMask).setFlags(aceFlags).build();

            acl.add(ace);

        }

        return acl;

    }

    // Returns true if NFSv4 ACLs not enabled on file system

    private static boolean isAclsEnabled(int fd) {

        try {

            long enabled = fpathconf(fd, _PC_ACL_ENABLED);

            if (enabled == _ACL_ACE_ENABLED)

                return true;

        } catch (UnixException x) {

        }

        return false;

    }

    @Override

    public List<AclEntry> getAcl()

        throws IOException

    {

        // permission check

        checkAccess(file, true, false);

        // open file (will fail if file is a link and not following links)

        int fd = file.openForAttributeAccess(followLinks);

        try {

            long address = unsafe.allocateMemory(SIZEOF_ACE_T * MAX_ACL_ENTRIES);

            try {

                // read ACL and decode it

                int n = facl(fd, ACE_GETACL, MAX_ACL_ENTRIES, address);

                assert n >= 0;

                return decode(address, n);

            } catch (UnixException x) {

                if ((x.errno() == ENOSYS) || !isAclsEnabled(fd)) {

                    throw new FileSystemException(file.getPathForExceptionMessage(),

                        null, x.getMessage() + " (file system does not support NFSv4 ACLs)");

                }

                x.rethrowAsIOException(file);

                return null;    // keep compiler happy

            } finally {

                unsafe.freeMemory(address);

            }

        } finally {

            close(fd);

        }

    }

    @Override

    public void setAcl(List<AclEntry> acl) throws IOException {

        // permission check

        checkAccess(file, false, true);

        // open file (will fail if file is a link and not following links)

        int fd = file.openForAttributeAccess(followLinks);

        try {

            // SECURITY: need to copy list as can change during processing

            acl = new ArrayList<AclEntry>(acl);

            int n = acl.size();

            long address = unsafe.allocateMemory(SIZEOF_ACE_T * n);

            try {

                encode(acl, address);

                facl(fd, ACE_SETACL, n, address);

            } catch (UnixException x) {

                if ((x.errno() == ENOSYS) || !isAclsEnabled(fd)) {

                    throw new FileSystemException(file.getPathForExceptionMessage(),

                        null, x.getMessage() + " (file system does not support NFSv4 ACLs)");

                }

                if (x.errno() == EINVAL && (n < 3))

                    throw new IOException("ACL must contain at least 3 entries");

                x.rethrowAsIOException(file);

            } finally {

                unsafe.freeMemory(address);

            }

        } finally {

            close(fd);

        }

    }

    @Override

    public UserPrincipal getOwner()

        throws IOException

    {

        checkAccess(file, true, false);

        try {

            UnixFileAttributes attrs =

                UnixFileAttributes.get(file, followLinks);

            return UnixUserPrincipals.fromUid(attrs.uid());

        } catch (UnixException x) {

            x.rethrowAsIOException(file);

            return null; // keep compile happy

        }

    }

    @Override

    public void setOwner(UserPrincipal owner) throws IOException {

        checkAccess(file, true, false);

        if (!(owner instanceof UnixUserPrincipals.User))

            throw new ProviderMismatchException();

        if (owner instanceof UnixUserPrincipals.Group)

            throw new IOException("'owner' parameter is a group");

        int uid = ((UnixUserPrincipals.User)owner).uid();

        try {

            if (followLinks) {

                lchown(file, uid, -1);

            } else {

                chown(file, uid, -1);

            }

        } catch (UnixException x) {

            x.rethrowAsIOException(file);

        }

    }

}