/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program 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.

 * This program 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 COPYING file that accompanied this code.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2012, 2014, Intel Corporation.
 * Use is subject to license terms.
 */
/*
 * Author: Brian Behlendorf <behlendorf1@llnl.gov>
 */
#include "mount_utils.h"
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <libzfs.h>

/* Persistent mount data is stored in these user attributes */
#define LDD_PREFIX		"lustre:"
#define LDD_VERSION_PROP	LDD_PREFIX "version"
#define LDD_FLAGS_PROP		LDD_PREFIX "flags"
#define LDD_INDEX_PROP		LDD_PREFIX "index"
#define LDD_FSNAME_PROP		LDD_PREFIX "fsname"
#define LDD_SVNAME_PROP		LDD_PREFIX "svname"
#define LDD_UUID_PROP		LDD_PREFIX "uuid"
#define LDD_USERDATA_PROP	LDD_PREFIX "userdata"
#define LDD_MOUNTOPTS_PROP	LDD_PREFIX "mountopts"

/* This structure is used to help bridge the gap between the ZFS
 * properties Lustre uses and their corresponding internal LDD fields.
 * It is meant to be used internally by the mount utility only. */
struct zfs_ldd_prop_bridge {
	/* Contains the publicly visible name for the property
	 * (i.e. what is shown when running "zfs get") */
	char *zlpb_prop_name;
	/* Contains the offset into the lustre_disk_data structure where
	 * the value of this property is or will be stored. (i.e. the
	 * property is read from and written to this offset within ldd) */
	int   zlpb_ldd_offset;
	/* Function pointer responsible for reading in the @prop
	 * property from @zhp and storing it in @ldd_field */
	int (*zlpb_get_prop_fn)(zfs_handle_t *zhp, char *prop, void *ldd_field);
	/* Function pointer responsible for writing the value of @ldd_field
	 * into the @prop dataset property in @zhp */
	int (*zlpb_set_prop_fn)(zfs_handle_t *zhp, char *prop, void *ldd_field);
};

/* Forward declarations needed to initialize the ldd prop bridge list */
static int zfs_get_prop_int(zfs_handle_t *, char *, void *);
static int zfs_set_prop_int(zfs_handle_t *, char *, void *);
static int zfs_get_prop_str(zfs_handle_t *, char *, void *);
static int zfs_set_prop_str(zfs_handle_t *, char *, void *);

/* Helper for initializing the entries in the special_ldd_prop_params list.
 *    - @name: stored directly in the zlpb_prop_name field
 *             (e.g. lustre:fsname, lustre:version, etc.)
 *    - @field: the field in the lustre_disk_data which directly maps to
 *              the @name property. (e.g. ldd_fsname, ldd_config_ver, etc.)
 *    - @type: The type of @field. Only "int" and "str" are supported.
 */
#define ZLB_INIT(name, field, type)			\
{							\
	name, offsetof(struct lustre_disk_data, field),	\
	zfs_get_prop_ ## type, zfs_set_prop_ ## type	\
}

/* These ldd properties are special because they all have their own
 * individual fields in the lustre_disk_data structure, as opposed to
 * being globbed into the ldd_params field. As such, these need special
 * handling when reading/writing the ldd structure to/from persistent
 * storage. */
struct zfs_ldd_prop_bridge special_ldd_prop_params[] = {
	ZLB_INIT(LDD_VERSION_PROP,   ldd_config_ver, int),
	ZLB_INIT(LDD_FLAGS_PROP,     ldd_flags,      int),
	ZLB_INIT(LDD_INDEX_PROP,     ldd_svindex,    int),
	ZLB_INIT(LDD_FSNAME_PROP,    ldd_fsname,     str),
	ZLB_INIT(LDD_SVNAME_PROP,    ldd_svname,     str),
	ZLB_INIT(LDD_UUID_PROP,      ldd_uuid,       str),
	ZLB_INIT(LDD_USERDATA_PROP,  ldd_userdata,   str),
	ZLB_INIT(LDD_MOUNTOPTS_PROP, ldd_mount_opts, str),
	{ NULL }
};

/* indicate if the ZFS OSD has been successfully setup */
static int osd_zfs_setup = 0;

static libzfs_handle_t *g_zfs;

void zfs_fini(void);

static int zfs_set_prop_int(zfs_handle_t *zhp, char *prop, void *val)
{
	char str[64];
	int ret;

	(void) snprintf(str, sizeof (str), "%i", *(int *)val);
	vprint("  %s=%s\n", prop, str);
	ret = zfs_prop_set(zhp, prop, str);

	return ret;
}

/*
 * Write the zfs property string, note that properties with a NULL or
 * zero-length value will not be written and 0 returned.
 */
static int zfs_set_prop_str(zfs_handle_t *zhp, char *prop, void *val)
{
	int ret = 0;

	if (val && strlen(val) > 0) {
		vprint("  %s=%s\n", prop, (char *)val);
		ret = zfs_prop_set(zhp, prop, (char *)val);
	}

	return ret;
}

/*
 * Map '<key>=<value> ...' pairs in the passed string to dataset properties
 * of the form 'lustre:<key>=<value>'.  Malformed <key>=<value> pairs will
 * be skipped.
 */
static int zfs_set_prop_params(zfs_handle_t *zhp, char *params)
{
	char *params_dup, *token, *key, *value;
	char *save_token = NULL;
	char prop_name[ZFS_MAXPROPLEN];
	int ret = 0;

	params_dup = strdup(params);
	if (params_dup == NULL)
		return ENOMEM;

	token = strtok_r(params_dup, " ", &save_token);
	while (token) {
		key = strtok(token, "=");
		if (key == NULL)
			continue;

		value = strtok(NULL, "=");
		if (value == NULL)
			continue;

		sprintf(prop_name, "%s%s", LDD_PREFIX, key);
		vprint("  %s=%s\n", prop_name, value);

		ret = zfs_prop_set(zhp, prop_name, value);
		if (ret)
			break;

		token = strtok_r(NULL, " ", &save_token);
	}

	free(params_dup);

	return ret;
}

static int zfs_check_hostid(struct mkfs_opts *mop)
{
	FILE *f;
	unsigned long hostid;
	int rc;

	if (strstr(mop->mo_ldd.ldd_params, PARAM_FAILNODE) == NULL)
		return 0;

	f = fopen("/sys/module/spl/parameters/spl_hostid", "r");
	if (f == NULL) {
		fatal();
		fprintf(stderr, "Failed to open spl_hostid: %s\n",
			strerror(errno));
		return errno;
	}
	rc = fscanf(f, "%li", &hostid);
	fclose(f);
	if (rc != 1) {
		fatal();
		fprintf(stderr, "Failed to read spl_hostid: %d\n", rc);
		return rc;
	}

	if (hostid == 0) {
		if (mop->mo_flags & MO_NOHOSTID_CHECK) {
			fprintf(stderr, "WARNING: spl_hostid not set. ZFS has "
				"no zpool import protection\n");
		} else {
			fatal();
			fprintf(stderr, "spl_hostid not set. See %s(8)",
				progname);
			return EINVAL;
		}
	}

	return 0;
}

static int osd_check_zfs_setup(void)
{
	if (osd_zfs_setup == 0) {
		/* setup failed */
		fatal();
		fprintf(stderr, "Failed to initialize ZFS library. Are the ZFS "
			"packages and modules correctly installed?\n");
	}
	return osd_zfs_setup == 1;
}

/* Write the server config as properties associated with the dataset */
int zfs_write_ldd(struct mkfs_opts *mop)
{
	struct lustre_disk_data *ldd = &mop->mo_ldd;
	char *ds = mop->mo_device;
	zfs_handle_t *zhp;
	struct zfs_ldd_prop_bridge *bridge;
	int i, ret = EINVAL;

	if (osd_check_zfs_setup() == 0)
		goto out;

	zhp = zfs_open(g_zfs, ds, ZFS_TYPE_FILESYSTEM);
	if (zhp == NULL) {
		fprintf(stderr, "Failed to open zfs dataset %s\n", ds);
		goto out;
	}

	ret = zfs_check_hostid(mop);
	if (ret != 0)
		goto out;

	vprint("Writing %s properties\n", ds);

	for (i = 0; special_ldd_prop_params[i].zlpb_prop_name != NULL; i++) {
		bridge = &special_ldd_prop_params[i];
		ret = bridge->zlpb_set_prop_fn(zhp, bridge->zlpb_prop_name,
					(void *)ldd + bridge->zlpb_ldd_offset);
		if (ret)
			goto out_close;
	}

	ret = zfs_set_prop_params(zhp, ldd->ldd_params);

out_close:
	zfs_close(zhp);
out:
	return ret;
}

static int zfs_get_prop_int(zfs_handle_t *zhp, char *prop, void *val)
{
	nvlist_t *propval;
	char *propstr;
	int ret;

	ret = nvlist_lookup_nvlist(zfs_get_user_props(zhp), prop, &propval);
	if (ret)
		return ret;

	ret = nvlist_lookup_string(propval, ZPROP_VALUE, &propstr);
	if (ret)
		return ret;

	errno = 0;
	*(__u32 *)val = strtoul(propstr, NULL, 10);
	if (errno)
		return errno;

	return ret;
}

static int zfs_get_prop_str(zfs_handle_t *zhp, char *prop, void *val)
{
	nvlist_t *propval;
	char *propstr;
	int ret;

	ret = nvlist_lookup_nvlist(zfs_get_user_props(zhp), prop, &propval);
	if (ret)
		return ret;

	ret = nvlist_lookup_string(propval, ZPROP_VALUE, &propstr);
	if (ret)
		return ret;

	(void) strcpy(val, propstr);

	return ret;
}

static int zfs_is_special_ldd_prop_param(char *name)
{
	int i;

	for (i = 0; special_ldd_prop_params[i].zlpb_prop_name != NULL; i++)
		if (!strcmp(name, special_ldd_prop_params[i].zlpb_prop_name))
			return 1;

	return 0;
}

static int zfs_get_prop_params(zfs_handle_t *zhp, char *param, int len)
{
	nvlist_t *props;
	nvpair_t *nvp;
	char key[ZFS_MAXPROPLEN];
	char *value;
	int ret = 0;

	props = zfs_get_user_props(zhp);
	if (props == NULL)
		return ENOENT;

	value = malloc(len);
	if (value == NULL)
		return ENOMEM;

	nvp = NULL;
	while (nvp = nvlist_next_nvpair(props, nvp), nvp) {
		ret = zfs_get_prop_str(zhp, nvpair_name(nvp), value);
		if (ret)
			break;

		if (strncmp(nvpair_name(nvp), LDD_PREFIX, strlen(LDD_PREFIX)))
			continue;

		if (zfs_is_special_ldd_prop_param(nvpair_name(nvp)))
			continue;

		sprintf(key, "%s=",  nvpair_name(nvp) + strlen(LDD_PREFIX));

		ret = add_param(param, key, value);
		if (ret)
			break;
	}

	free(value);

	return ret;
}

/*
 * Read the server config as properties associated with the dataset.
 * Missing entries as not treated error and are simply skipped.
 */
int zfs_read_ldd(char *ds,  struct lustre_disk_data *ldd)
{
	zfs_handle_t *zhp;
	struct zfs_ldd_prop_bridge *bridge;
	int i, ret = EINVAL;

	if (osd_check_zfs_setup() == 0)
		return EINVAL;

	zhp = zfs_open(g_zfs, ds, ZFS_TYPE_FILESYSTEM);
	if (zhp == NULL)
		goto out;

	for (i = 0; special_ldd_prop_params[i].zlpb_prop_name != NULL; i++) {
		bridge = &special_ldd_prop_params[i];
		ret = bridge->zlpb_get_prop_fn(zhp, bridge->zlpb_prop_name,
					(void *)ldd + bridge->zlpb_ldd_offset);
		if (ret && (ret != ENOENT))
			goto out_close;
	}

	ret = zfs_get_prop_params(zhp, ldd->ldd_params, 4096);
	if (ret && (ret != ENOENT))
		goto out_close;

	ldd->ldd_mount_type = LDD_MT_ZFS;
	ret = 0;
out_close:
	zfs_close(zhp);
out:
	return ret;
}

int zfs_is_lustre(char *ds, unsigned *mount_type)
{
	struct lustre_disk_data tmp_ldd;
	int ret;

	if (osd_zfs_setup == 0)
		return 0;

	ret = zfs_read_ldd(ds, &tmp_ldd);
	if ((ret == 0) && (tmp_ldd.ldd_config_ver > 0) &&
	    (strlen(tmp_ldd.ldd_svname) > 0)) {
		*mount_type = tmp_ldd.ldd_mount_type;
		return 1;
	}

	return 0;
}

static char *zfs_mkfs_opts(struct mkfs_opts *mop, char *str, int len)
{
	memset(str, 0, len);

	if (strlen(mop->mo_mkfsopts) != 0)
		snprintf(str, len, " -o %s", mop->mo_mkfsopts);

	return str;
}

static int zfs_create_vdev(struct mkfs_opts *mop, char *vdev)
{
	int ret = 0;

	/* Silently ignore reserved vdev names */
	if ((strncmp(vdev, "disk", 4) == 0) ||
	    (strncmp(vdev, "file", 4) == 0) ||
	    (strncmp(vdev, "mirror", 6) == 0) ||
	    (strncmp(vdev, "raidz", 5) == 0) ||
	    (strncmp(vdev, "spare", 5) == 0) ||
	    (strncmp(vdev, "log", 3) == 0) ||
	    (strncmp(vdev, "cache", 5) == 0))
		return ret;

	/*
	 * Verify a file exists at the provided absolute path.  If it doesn't
	 * and mo_device_kb is set attempt to create a file vdev to be used.
	 * Relative paths will be passed directly to 'zpool create' which
	 * will check multiple multiple locations under /dev/.
	 */
	if (vdev[0] == '/') {
		ret = access(vdev, F_OK);
		if (ret == 0)
			return ret;

		ret = errno;
		if (ret != ENOENT) {
			fatal();
			fprintf(stderr, "Unable to access required vdev "
				"for pool %s (%d)\n", vdev, ret);
			return ret;
		}

		if (mop->mo_device_kb == 0) {
			fatal();
			fprintf(stderr, "Unable to create vdev due to "
				"missing --device-size=#N(KB) parameter\n");
			return EINVAL;
		}

		ret = file_create(vdev, mop->mo_device_kb);
		if (ret) {
			fatal();
			fprintf(stderr, "Unable to create vdev %s (%d)\n",
				vdev, ret);
			return ret;
		}
	}

	return ret;
}

int zfs_make_lustre(struct mkfs_opts *mop)
{
	zfs_handle_t *zhp;
	zpool_handle_t *php;
	char *pool = NULL;
	char *mkfs_cmd = NULL;
	char *mkfs_tmp = NULL;
	char *ds = mop->mo_device;
	int pool_exists = 0, ret;

	if (osd_check_zfs_setup() == 0)
		return EINVAL;

	/* no automatic index with zfs backend */
	if (mop->mo_ldd.ldd_flags & LDD_F_NEED_INDEX) {
		fatal();
		fprintf(stderr, "The target index must be specified with "
				"--index\n");
		return EINVAL;
	}

	ret = zfs_check_hostid(mop);
	if (ret != 0)
		goto out;

	pool = strdup(ds);
	if (pool == NULL)
		return ENOMEM;

	mkfs_cmd = malloc(PATH_MAX);
	if (mkfs_cmd == NULL) {
		ret = ENOMEM;
		goto out;
	}

	mkfs_tmp = malloc(PATH_MAX);
	if (mkfs_tmp == NULL) {
		ret = ENOMEM;
		goto out;
	}

	/* Due to zfs_prepare_lustre() check the '/' must exist */
	strchr(pool, '/')[0] = '\0';

	/* If --reformat was given attempt to destroy the previous dataset */
	if ((mop->mo_flags & MO_FORCEFORMAT) &&
	    ((zhp = zfs_open(g_zfs, ds, ZFS_TYPE_FILESYSTEM)) != NULL)) {

		ret = zfs_destroy(zhp, 0);
		if (ret) {
			zfs_close(zhp);
			fprintf(stderr, "Failed destroy zfs dataset %s (%d)\n",
				ds, ret);
			goto out;
		}

		zfs_close(zhp);
	}

	/*
	 * Create the zpool if the vdevs have been specified and the pool
	 * does not already exists.  The pool creation itself will be done
	 * with the zpool command rather than the zpool_create() library call
	 * so the existing zpool error handling can be leveraged.
	 */
	php = zpool_open(g_zfs, pool);
	if (php) {
		pool_exists = 1;
		zpool_close(php);
	}

	if ((mop->mo_pool_vdevs != NULL) && (pool_exists == 0)) {

		memset(mkfs_cmd, 0, PATH_MAX);
		snprintf(mkfs_cmd, PATH_MAX,
			"zpool create -f -O canmount=off %s", pool);

		/* Append the vdev config and create file vdevs as required */
		while (*mop->mo_pool_vdevs != NULL) {
			strscat(mkfs_cmd, " ", PATH_MAX);
			strscat(mkfs_cmd, *mop->mo_pool_vdevs, PATH_MAX);

			ret = zfs_create_vdev(mop, *mop->mo_pool_vdevs);
			if (ret)
				goto out;

			mop->mo_pool_vdevs++;
		}

		vprint("mkfs_cmd = %s\n", mkfs_cmd);
		ret = run_command(mkfs_cmd, PATH_MAX);
		if (ret) {
			fatal();
			fprintf(stderr, "Unable to create pool %s (%d)\n",
				pool, ret);
			goto out;
		}
	}

	/*
	 * Create the ZFS filesystem with any required mkfs options:
	 * - canmount=off is set to prevent zfs automounting
	 * - xattr=sa is set to use system attribute based xattrs
	 */
	memset(mkfs_cmd, 0, PATH_MAX);
	snprintf(mkfs_cmd, PATH_MAX,
		 "zfs create -o canmount=off -o xattr=sa%s %s",
		 zfs_mkfs_opts(mop, mkfs_tmp, PATH_MAX), ds);

	vprint("mkfs_cmd = %s\n", mkfs_cmd);
	ret = run_command(mkfs_cmd, PATH_MAX);
	if (ret) {
		fatal();
		fprintf(stderr, "Unable to create filesystem %s (%d)\n",
			ds, ret);
		goto out;
	}

out:
	if (pool != NULL)
		free(pool);

	if (mkfs_cmd != NULL)
		free(mkfs_cmd);

	if (mkfs_tmp != NULL)
		free(mkfs_tmp);

	return ret;
}

int zfs_enable_quota(struct mkfs_opts *mop)
{
	fprintf(stderr, "this option is not only valid for zfs\n");
	return ENOSYS;
}

int zfs_prepare_lustre(struct mkfs_opts *mop,
		       char *wanted_mountopts, size_t len)
{
	if (osd_check_zfs_setup() == 0)
		return EINVAL;

	if (zfs_name_valid(mop->mo_device, ZFS_TYPE_FILESYSTEM) == 0) {
		fatal();
		fprintf(stderr, "Invalid filesystem name %s\n", mop->mo_device);
		return EINVAL;
	}

	if (strchr(mop->mo_device, '/') == NULL) {
		fatal();
		fprintf(stderr, "Missing pool in filesystem name %s\n",
			mop->mo_device);
		return EINVAL;
	}

	return 0;
}

int zfs_tune_lustre(char *dev, struct mount_opts *mop)
{
	if (osd_check_zfs_setup() == 0)
		return EINVAL;

	return 0;
}

int zfs_label_lustre(struct mount_opts *mop)
{
	zfs_handle_t *zhp;
	int ret;

	if (osd_check_zfs_setup() == 0)
		return EINVAL;

	zhp = zfs_open(g_zfs, mop->mo_source, ZFS_TYPE_FILESYSTEM);
	if (zhp == NULL)
		return EINVAL;

	ret = zfs_set_prop_str(zhp, LDD_SVNAME_PROP, mop->mo_ldd.ldd_svname);
	zfs_close(zhp);

	return ret;
}

int zfs_init(void)
{
	int ret = 0;

	g_zfs = libzfs_init();
	if (g_zfs == NULL) {
		fprintf(stderr, "Failed to initialize ZFS library\n");
		ret = EINVAL;
	} else {
		osd_zfs_setup = 1;
	}

	return ret;
}

void zfs_fini(void)
{
	if (g_zfs) {
		libzfs_fini(g_zfs);
		g_zfs = NULL;
	}
	osd_zfs_setup = 0;
}