/*
   Copyright (c) 2017 Red Hat, Inc. <http://www.redhat.com>
   This file is part of GlusterFS.

   This file is licensed to you under your choice of the GNU Lesser
   General Public License, version 3 or any later version (LGPLv3 or
   later), or the GNU General Public License, version 2 (GPLv2), in all
   cases as published by the Free Software Foundation.
*/

#include <glusterfs/xlator.h>

#include "selinux.h"
#include "selinux-messages.h"
#include "selinux-mem-types.h"
#include <glusterfs/compat-errno.h>

static int
selinux_fgetxattr_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                      int op_ret, int op_errno, dict_t *dict, dict_t *xdata)
{
    int ret = 0;
    char *name = cookie;

    if (op_errno == 0 && dict && name &&
        (!strcmp(name, SELINUX_GLUSTER_XATTR))) {
        ret = dict_rename_key(dict, SELINUX_GLUSTER_XATTR, SELINUX_XATTR);
        if (ret < 0)
            gf_msg(this->name, GF_LOG_ERROR, op_errno,
                   SL_MSG_SELINUX_GLUSTER_XATTR_MISSING,
                   "getxattr failed for %s", SELINUX_XATTR);
    }

    STACK_UNWIND_STRICT(fgetxattr, frame, op_ret, op_errno, dict, xdata);
    return ret;
}

static int
selinux_fgetxattr(call_frame_t *frame, xlator_t *this, fd_t *fd,
                  const char *name, dict_t *xdata)
{
    selinux_priv_t *priv = NULL;
    int32_t op_ret = -1;
    int32_t op_errno = EINVAL;
    char *xattr_name = (char *)name;

    priv = this->private;

    GF_VALIDATE_OR_GOTO("selinux", priv, err);

    /* name can be NULL for listxattr calls */
    if (!priv->selinux_enabled || !name)
        goto off;

    if (strcmp(name, SELINUX_XATTR) == 0)
        xattr_name = SELINUX_GLUSTER_XATTR;

off:
    STACK_WIND_COOKIE(frame, selinux_fgetxattr_cbk, xattr_name,
                      FIRST_CHILD(this), FIRST_CHILD(this)->fops->fgetxattr, fd,
                      xattr_name, xdata);
    return 0;
err:
    STACK_UNWIND_STRICT(fgetxattr, frame, op_ret, op_errno, NULL, xdata);

    return 0;
}

static int
selinux_getxattr_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                     int op_ret, int op_errno, dict_t *dict, dict_t *xdata)
{
    int ret = 0;
    char *name = cookie;

    if (op_errno == 0 && dict && name &&
        (!strcmp(name, SELINUX_GLUSTER_XATTR))) {
        ret = dict_rename_key(dict, SELINUX_GLUSTER_XATTR, SELINUX_XATTR);
        if (ret < 0)
            gf_msg(this->name, GF_LOG_ERROR, op_errno,
                   SL_MSG_SELINUX_GLUSTER_XATTR_MISSING,
                   "getxattr failed for %s", SELINUX_XATTR);
    }

    STACK_UNWIND_STRICT(getxattr, frame, op_ret, op_errno, dict, xdata);

    return 0;
}

static int
selinux_getxattr(call_frame_t *frame, xlator_t *this, loc_t *loc,
                 const char *name, dict_t *xdata)
{
    selinux_priv_t *priv = NULL;
    int32_t op_ret = -1;
    int32_t op_errno = EINVAL;
    char *xattr_name = (char *)name;

    priv = this->private;

    GF_VALIDATE_OR_GOTO("selinux", priv, err);

    /* name can be NULL for listxattr calls */
    if (!priv->selinux_enabled || !name)
        goto off;

    if (strcmp(name, SELINUX_XATTR) == 0)
        xattr_name = SELINUX_GLUSTER_XATTR;

off:
    STACK_WIND_COOKIE(frame, selinux_getxattr_cbk, xattr_name,
                      FIRST_CHILD(this), FIRST_CHILD(this)->fops->getxattr, loc,
                      xattr_name, xdata);
    return 0;
err:
    STACK_UNWIND_STRICT(getxattr, frame, op_ret, op_errno, NULL, xdata);
    return 0;
}

static int
selinux_fsetxattr_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                      int op_ret, int op_errno, dict_t *xdata)
{
    STACK_UNWIND_STRICT(fsetxattr, frame, op_ret, op_errno, xdata);
    return 0;
}

static int
selinux_fsetxattr(call_frame_t *frame, xlator_t *this, fd_t *fd, dict_t *dict,
                  int flags, dict_t *xdata)
{
    selinux_priv_t *priv = NULL;
    int32_t op_ret = -1;
    int32_t op_errno = EINVAL;
    int32_t ret = -1;

    priv = this->private;

    GF_VALIDATE_OR_GOTO("selinux", priv, err);

    if (!priv->selinux_enabled && !dict)
        goto off;

    ret = dict_rename_key(dict, SELINUX_XATTR, SELINUX_GLUSTER_XATTR);
    if (ret < 0 && ret != -ENODATA)
        goto err;

off:
    STACK_WIND(frame, selinux_fsetxattr_cbk, FIRST_CHILD(this),
               FIRST_CHILD(this)->fops->fsetxattr, fd, dict, flags, xdata);

    return 0;
err:
    STACK_UNWIND_STRICT(fsetxattr, frame, op_ret, op_errno, xdata);
    return 0;
}

static int
selinux_setxattr_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                     int op_ret, int op_errno, dict_t *xdata)
{
    STACK_UNWIND_STRICT(setxattr, frame, op_ret, op_errno, xdata);
    return 0;
}

static int
selinux_setxattr(call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *dict,
                 int flags, dict_t *xdata)
{
    selinux_priv_t *priv = NULL;
    int32_t op_ret = -1;
    int32_t op_errno = EINVAL;
    int32_t ret = -1;

    priv = this->private;

    GF_VALIDATE_OR_GOTO("selinux", priv, err);

    if (!priv->selinux_enabled && !dict)
        goto off;

    ret = dict_rename_key(dict, SELINUX_XATTR, SELINUX_GLUSTER_XATTR);
    if (ret < 0 && ret != -ENODATA)
        goto err;

off:
    STACK_WIND(frame, selinux_setxattr_cbk, FIRST_CHILD(this),
               FIRST_CHILD(this)->fops->setxattr, loc, dict, flags, xdata);
    return 0;
err:
    STACK_UNWIND_STRICT(setxattr, frame, op_ret, op_errno, xdata);
    return 0;
}

int32_t
mem_acct_init(xlator_t *this)
{
    int ret = -1;

    GF_VALIDATE_OR_GOTO("selinux", this, out);

    ret = xlator_mem_acct_init(this, gf_selinux_mt_end + 1);

    if (ret != 0) {
        gf_msg(this->name, GF_LOG_ERROR, 0, SL_MSG_MEM_ACCT_INIT_FAILED,
               "Memory accounting init failed");
        return ret;
    }
out:
    return ret;
}

int32_t
init(xlator_t *this)
{
    int32_t ret = -1;
    selinux_priv_t *priv = NULL;

    GF_VALIDATE_OR_GOTO("selinux", this, out);

    if (!this->children || this->children->next) {
        gf_msg(this->name, GF_LOG_WARNING, 0, SL_MSG_INVALID_VOLFILE,
               "Error: SELinux (%s) not configured with exactly one "
               "child",
               this->name);
        return -1;
    }

    if (this->parents == NULL) {
        gf_msg(this->name, GF_LOG_WARNING, 0, SL_MSG_INVALID_VOLFILE,
               "Dangling volume. Please check the volfile");
    }

    priv = GF_CALLOC(1, sizeof(*priv), gf_selinux_mt_selinux_priv_t);
    if (!priv) {
        gf_log(this->name, GF_LOG_ERROR, "out of memory");
        goto out;
    }

    GF_OPTION_INIT("selinux", priv->selinux_enabled, bool, out);

    this->local_pool = mem_pool_new(selinux_priv_t, 64);
    if (!this->local_pool) {
        gf_msg(this->name, GF_LOG_ERROR, ENOMEM, SL_MSG_ENOMEM,
               "Failed to create local_t's memory pool");
        goto out;
    }

    this->private = (void *)priv;
    ret = 0;
out:
    if (ret) {
        GF_FREE(priv);
        mem_pool_destroy(this->local_pool);
        this->local_pool = NULL;
    }
    return ret;
}

int
reconfigure(xlator_t *this, dict_t *options)
{
    int32_t ret = -1;
    selinux_priv_t *priv = NULL;

    priv = this->private;

    GF_OPTION_RECONF("selinux", priv->selinux_enabled, options, bool, out);

    ret = 0;
out:
    return ret;
}

void
fini(xlator_t *this)
{
    selinux_priv_t *priv = NULL;

    priv = this->private;
    GF_FREE(priv);

    mem_pool_destroy(this->local_pool);
    this->local_pool = NULL;

    return;
}

struct xlator_fops fops = {
    .getxattr = selinux_getxattr,
    .fgetxattr = selinux_fgetxattr,
    .setxattr = selinux_setxattr,
    .fsetxattr = selinux_fsetxattr,
};

struct xlator_cbks cbks = {};

struct volume_options options[] = {
    {
        .key = {"selinux"},
        .type = GF_OPTION_TYPE_BOOL,
        .default_value = "on",
        .description = "Enable/disable selinux translator",
        .op_version = {GD_OP_VERSION_3_11_0},
        .flags = OPT_FLAG_SETTABLE,
        .tags = {"security", "linux"},
    },
    {
        .key = {NULL},
    }};

xlator_api_t xlator_api = {
    .init = init,
    .fini = fini,
    .reconfigure = reconfigure,
    .mem_acct_init = mem_acct_init,
    .op_version = {1}, /* Present from the initial version */
    .fops = &fops,
    .cbks = &cbks,
    .options = options,
    .identifier = "selinux",
    .category = GF_MAINTAINED,
};