// SPDX-License-Identifier: LGPL-2.1
/*
 * Copyright IBM Corporation, 2010
 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/fs_struct.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/posix_acl_xattr.h>
#include "xattr.h"
#include "acl.h"
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"

static struct posix_acl *v9fs_fid_get_acl(struct p9_fid *fid, const char *name)
{
        ssize_t size;
        void *value = NULL;
        struct posix_acl *acl = NULL;

        size = v9fs_fid_xattr_get(fid, name, NULL, 0);
        if (size < 0)
                return ERR_PTR(size);
        if (size == 0)
                return ERR_PTR(-ENODATA);

        value = kzalloc(size, GFP_NOFS);
        if (!value)
                return ERR_PTR(-ENOMEM);

        size = v9fs_fid_xattr_get(fid, name, value, size);
        if (size < 0)
                acl = ERR_PTR(size);
        else if (size == 0)
                acl = ERR_PTR(-ENODATA);
        else
                acl = posix_acl_from_xattr(&init_user_ns, value, size);
        kfree(value);
        return acl;
}

static struct posix_acl *v9fs_acl_get(struct dentry *dentry, const char *name)
{
        struct p9_fid *fid;
        struct posix_acl *acl = NULL;

        fid = v9fs_fid_lookup(dentry);
        if (IS_ERR(fid))
                return ERR_CAST(fid);

        acl = v9fs_fid_get_acl(fid, name);
        p9_fid_put(fid);
        return acl;
}

static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, const char *name)
{
        int retval;
        struct posix_acl *acl = NULL;

        acl = v9fs_fid_get_acl(fid, name);
        if (!IS_ERR(acl))
                return acl;

        retval = PTR_ERR(acl);
        if (retval == -ENODATA || retval == -ENOSYS || retval == -EOPNOTSUPP)
                return NULL;

        /* map everything else to -EIO */
        return ERR_PTR(-EIO);
}

int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
{
        int retval = 0;
        struct posix_acl *pacl, *dacl;
        struct v9fs_session_info *v9ses;

        v9ses = v9fs_inode2v9ses(inode);
        if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
                        ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
                set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
                set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
                return 0;
        }
        /* get the default/access acl values and cache them */
        dacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_DEFAULT);
        pacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_ACCESS);

        if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
                set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
                set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
        } else
                retval = -EIO;

        if (!IS_ERR(dacl))
                posix_acl_release(dacl);

        if (!IS_ERR(pacl))
                posix_acl_release(pacl);

        return retval;
}

static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
{
        struct posix_acl *acl;
        /*
         * 9p Always cache the acl value when
         * instantiating the inode (v9fs_inode_from_fid)
         */
        acl = get_cached_acl(inode, type);
        BUG_ON(is_uncached_acl(acl));
        return acl;
}

struct posix_acl *v9fs_iop_get_inode_acl(struct inode *inode, int type, bool rcu)
{
        struct v9fs_session_info *v9ses;

        if (rcu)
                return ERR_PTR(-ECHILD);

        v9ses = v9fs_inode2v9ses(inode);
        if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
                        ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
                /*
                 * On access = client  and acl = on mode get the acl
                 * values from the server
                 */
                return NULL;
        }
        return v9fs_get_cached_acl(inode, type);

}

struct posix_acl *v9fs_iop_get_acl(struct mnt_idmap *idmap,
                                   struct dentry *dentry, int type)
{
        struct v9fs_session_info *v9ses;

        v9ses = v9fs_dentry2v9ses(dentry);
        /* We allow set/get/list of acl when access=client is not specified. */
        if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
                return v9fs_acl_get(dentry, posix_acl_xattr_name(type));
        return v9fs_get_cached_acl(d_inode(dentry), type);
}

int v9fs_iop_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
                     struct posix_acl *acl, int type)
{
        int retval;
        size_t size = 0;
        void *value = NULL;
        const char *acl_name;
        struct v9fs_session_info *v9ses;
        struct inode *inode = d_inode(dentry);

        if (acl) {
                retval = posix_acl_valid(inode->i_sb->s_user_ns, acl);
                if (retval)
                        goto err_out;

                value = posix_acl_to_xattr(&init_user_ns, acl, &size, GFP_NOFS);
                if (!value) {
                        retval = -ENOMEM;
                        goto err_out;
                }
        }

        /*
         * set the attribute on the remote. Without even looking at the
         * xattr value. We leave it to the server to validate
         */
        acl_name = posix_acl_xattr_name(type);
        v9ses = v9fs_dentry2v9ses(dentry);
        if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) {
                retval = v9fs_xattr_set(dentry, acl_name, value, size, 0);
                goto err_out;
        }

        if (S_ISLNK(inode->i_mode)) {
                retval = -EOPNOTSUPP;
                goto err_out;
        }

        if (!inode_owner_or_capable(&nop_mnt_idmap, inode)) {
                retval = -EPERM;
                goto err_out;
        }

        switch (type) {
        case ACL_TYPE_ACCESS:
                if (acl) {
                        struct iattr iattr = {};
                        struct posix_acl *acl_mode = acl;

                        retval = posix_acl_update_mode(&nop_mnt_idmap, inode,
                                                       &iattr.ia_mode,
                                                       &acl_mode);
                        if (retval)
                                goto err_out;
                        if (!acl_mode) {
                                /*
                                 * ACL can be represented by the mode bits.
                                 * So don't update ACL below.
                                 */
                                kfree(value);
                                value = NULL;
                                size = 0;
                        }
                        iattr.ia_valid = ATTR_MODE;
                        /*
                         * FIXME should we update ctime ?
                         * What is the following setxattr update the mode ?
                         */
                        v9fs_vfs_setattr_dotl(&nop_mnt_idmap, dentry, &iattr);
                }
                break;
        case ACL_TYPE_DEFAULT:
                if (!S_ISDIR(inode->i_mode)) {
                        retval = acl ? -EINVAL : 0;
                        goto err_out;
                }
                break;
        }

        retval = v9fs_xattr_set(dentry, acl_name, value, size, 0);
        if (!retval)
                set_cached_acl(inode, type, acl);

err_out:
        kfree(value);
        return retval;
}

static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl)
{
        int retval;
        char *name;
        size_t size;
        void *buffer;

        if (!acl)
                return 0;

        /* Set a setxattr request to server */
        buffer = posix_acl_to_xattr(&init_user_ns, acl, &size, GFP_KERNEL);
        if (!buffer)
                return -ENOMEM;

        switch (type) {
        case ACL_TYPE_ACCESS:
                name = XATTR_NAME_POSIX_ACL_ACCESS;
                break;
        case ACL_TYPE_DEFAULT:
                name = XATTR_NAME_POSIX_ACL_DEFAULT;
                break;
        default:
                BUG();
        }
        retval = v9fs_fid_xattr_set(fid, name, buffer, size, 0);
        kfree(buffer);
        return retval;
}

int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid)
{
        int retval = 0;
        struct posix_acl *acl;

        if (S_ISLNK(inode->i_mode))
                return -EOPNOTSUPP;
        acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
        if (acl) {
                retval = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
                if (retval)
                        return retval;
                set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
                retval = v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
                posix_acl_release(acl);
        }
        return retval;
}

int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid,
                        struct posix_acl *dacl, struct posix_acl *acl)
{
        set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
        set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
        v9fs_set_acl(fid, ACL_TYPE_DEFAULT, dacl);
        v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
        return 0;
}

void v9fs_put_acl(struct posix_acl *dacl,
                  struct posix_acl *acl)
{
        posix_acl_release(dacl);
        posix_acl_release(acl);
}

int v9fs_acl_mode(struct inode *dir, umode_t *modep,
                  struct posix_acl **dpacl, struct posix_acl **pacl)
{
        int retval = 0;
        umode_t mode = *modep;
        struct posix_acl *acl = NULL;

        if (!S_ISLNK(mode)) {
                acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
                if (IS_ERR(acl))
                        return PTR_ERR(acl);
                if (!acl)
                        mode &= ~current_umask();
        }
        if (acl) {
                if (S_ISDIR(mode))
                        *dpacl = posix_acl_dup(acl);
                retval = __posix_acl_create(&acl, GFP_NOFS, &mode);
                if (retval < 0)
                        return retval;
                if (retval > 0)
                        *pacl = acl;
                else
                        posix_acl_release(acl);
        }
        *modep  = mode;
        return 0;
}