/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include <libzfs.h>
#include <string.h>
#include <libshare.h>
#include "libshare_impl.h"
#include <libintl.h>

extern sa_share_t _sa_add_share(sa_group_t, char *, int, int *);
extern sa_group_t _sa_create_zfs_group(sa_group_t, char *);
extern char *sa_fstype(char *);
extern void set_node_attr(void *, char *, char *);
extern int sa_is_share(void *);

/*
 * File system specific code for ZFS. The original code was stolen
 * from the "zfs" command and modified to better suit this library's
 * usage.
 */

typedef struct get_all_cbdata {
	zfs_handle_t	**cb_handles;
	size_t		cb_alloc;
	size_t		cb_used;
} get_all_cbdata_t;

static libzfs_handle_t *zfs_libhandle = NULL;
static zfs_handle_t **zfs_list = NULL;
static size_t zfs_list_count = 0;

/*
 * sa_zfs_init()
 *
 * initialize an access handle into libzfs
 */

void
sa_zfs_init()
{
	zfs_libhandle = libzfs_init();
	libzfs_print_on_error(zfs_libhandle, B_TRUE);
}

/*
 * sa_zfs_fini()
 *
 * cleanup data structures and the libzfs handle used for accessing
 * zfs file share info.
 */

void
sa_zfs_fini()
{
	if (zfs_libhandle != NULL) {
	    libzfs_fini(zfs_libhandle);
	    zfs_libhandle = NULL;
	    if (zfs_list != NULL) {
		/*
		 * contents of zfs_list were already freed by the call to
		 * libzfs_fini().
		 */
		free(zfs_list);
		zfs_list = NULL;
	    }
	}
}

/*
 * get_one_filesystem(zfs_handle_t, data)
 *
 * an interator function called while iterating through the ZFS
 * root. It accumulates into an array of file system handles that can
 * be used to derive info about those file systems.
 */

static int
get_one_filesystem(zfs_handle_t *zhp, void *data)
{
	get_all_cbdata_t *cbp = data;

	/*
	 * Skip any zvols
	 */
	if (zfs_get_type(zhp) != ZFS_TYPE_FILESYSTEM) {
		zfs_close(zhp);
		return (0);
	}

	if (cbp->cb_alloc == cbp->cb_used) {
		zfs_handle_t **handles;

		if (cbp->cb_alloc == 0)
			cbp->cb_alloc = 64;
		else
			cbp->cb_alloc *= 2;

		handles = calloc(1, cbp->cb_alloc * sizeof (void *));
		if (handles == NULL) {
		    return (0);
		}

		if (cbp->cb_handles) {
			(void) memcpy(handles, cbp->cb_handles,
			    cbp->cb_used * sizeof (void *));
			free(cbp->cb_handles);
		}

		cbp->cb_handles = handles;
	}

	cbp->cb_handles[cbp->cb_used++] = zhp;

	return (zfs_iter_filesystems(zhp, get_one_filesystem, data));
}

/*
 * get_all_filesystems(zfs_handle_t ***fslist, size_t *count)
 *
 * iterate through all ZFS file systems starting at the root. Returns
 * a count and an array of handle pointers. Allocating is only done
 * once. The caller does not need to free since it will be done at
 * sa_zfs_fini() time.
 */

static void
get_all_filesystems(zfs_handle_t ***fslist, size_t *count)
{
	get_all_cbdata_t cb = { 0 };

	if (zfs_list != NULL) {
	    *fslist = zfs_list;
	    *count = zfs_list_count;
	    return;
	}

	(void) zfs_iter_root(zfs_libhandle, get_one_filesystem, &cb);

	zfs_list = *fslist = cb.cb_handles;
	zfs_list_count = *count = cb.cb_used;
}

/*
 * mountpoint_compare(a, b)
 *
 * compares the mountpoint on two zfs file systems handles.
 * returns values following strcmp() model.
 */

static int
mountpoint_compare(const void *a, const void *b)
{
	zfs_handle_t **za = (zfs_handle_t **)a;
	zfs_handle_t **zb = (zfs_handle_t **)b;
	char mounta[MAXPATHLEN];
	char mountb[MAXPATHLEN];

	verify(zfs_prop_get(*za, ZFS_PROP_MOUNTPOINT, mounta,
	    sizeof (mounta), NULL, NULL, 0, B_FALSE) == 0);
	verify(zfs_prop_get(*zb, ZFS_PROP_MOUNTPOINT, mountb,
	    sizeof (mountb), NULL, NULL, 0, B_FALSE) == 0);

	return (strcmp(mounta, mountb));
}

/*
 * get_zfs_dataset(path)
 *
 * get the name of the ZFS dataset the path is equivalent to.  The
 * dataset name is used for get/set of ZFS properties since libzfs
 * requires a dataset to do a zfs_open().
 */

static char *
get_zfs_dataset(char *path)
{
	size_t i, count = 0;
	char *dataset = NULL;
	zfs_handle_t **zlist;
	char mountpoint[ZFS_MAXPROPLEN];

	get_all_filesystems(&zlist, &count);
	qsort(zlist, count, sizeof (void *), mountpoint_compare);
	for (i = 0; i < count; i++) {
	    /* must have a mountpoint */
	    if (zfs_prop_get(zlist[i], ZFS_PROP_MOUNTPOINT, mountpoint,
		sizeof (mountpoint), NULL, NULL, 0, B_FALSE) != 0) {
		/* no mountpoint */
		continue;
	    }

	    /* mountpoint must be a path */
	    if (strcmp(mountpoint, ZFS_MOUNTPOINT_NONE) == 0 ||
		strcmp(mountpoint, ZFS_MOUNTPOINT_LEGACY) == 0)
		continue;

	    /* canmount must be set */
	    if (!zfs_prop_get_int(zlist[i], ZFS_PROP_CANMOUNT))
		continue;

	/*
	 * have a mountable handle but want to skip those marked none
	 * and legacy
	 */
	    if (strcmp(mountpoint, path) == 0) {
		dataset = (char *)zfs_get_name(zlist[i]);
		break;
	    }

	}

	if (dataset != NULL) {
	    dataset = strdup(dataset);
	}
	return (dataset);
}

/*
 * get_zfs_property(dataset, property)
 *
 * Get the file system property specified from the ZFS dataset.
 */

static char *
get_zfs_property(char *dataset, zfs_prop_t property)
{
	zfs_handle_t *handle = NULL;
	char shareopts[ZFS_MAXPROPLEN];
	libzfs_handle_t *libhandle;

	libhandle = libzfs_init();
	if (libhandle != NULL) {
	    handle = zfs_open(libhandle, dataset, ZFS_TYPE_FILESYSTEM);
	    if (handle != NULL) {
		if (zfs_prop_get(handle, property, shareopts,
				sizeof (shareopts), NULL, NULL, 0,
				B_FALSE) == 0) {
		    zfs_close(handle);
		    libzfs_fini(libhandle);
		    return (strdup(shareopts));
		}
		zfs_close(handle);
	    }
	    libzfs_fini(libhandle);
	}
	return (NULL);
}

/*
 * sa_zfs_is_shared(path)
 *
 * Check to see if the ZFS path provided has the sharenfs option set
 * or not.
 */

int
sa_zfs_is_shared(char *path)
{
	int ret = 0;
	char *dataset;
	zfs_handle_t *handle = NULL;
	char shareopts[ZFS_MAXPROPLEN];
	libzfs_handle_t *libhandle;

	dataset = get_zfs_dataset(path);
	if (dataset != NULL) {
	    libhandle = libzfs_init();
	    if (libhandle != NULL) {
		handle = zfs_open(libhandle, dataset, ZFS_TYPE_FILESYSTEM);
		if (handle != NULL) {
		    if (zfs_prop_get(handle, ZFS_PROP_SHARENFS, shareopts,
					sizeof (shareopts), NULL, NULL, 0,
					B_FALSE) == 0 &&
			strcmp(shareopts, "off") != 0)
			ret = 1; /* it is shared */
		    zfs_close(handle);
		}
		libzfs_fini(libhandle);
	    }
	    free(dataset);
	}
	return (ret);
}

/*
 * find_or_create_group(groupname, proto, *err)
 *
 * While walking the ZFS tree, we need to add shares to a defined
 * group. If the group doesn't exist, create it first, making sure it
 * is marked as a ZFS group.
 *
 * Note that all ZFS shares are in a subgroup of the top level group
 * called "zfs".
 */

static sa_group_t
find_or_create_group(char *groupname, char *proto, int *err)
{
	sa_group_t group;
	sa_optionset_t optionset;
	int ret = SA_OK;

	/*
	 * we check to see if the "zfs" group exists. Since this
	 * should be the top level group, we don't want the
	 * parent. This is to make sure the zfs group has been created
	 * and to created if it hasn't been.
	 */
	group = sa_get_group(groupname);
	if (group == NULL) {
	    group = sa_create_group(groupname, &ret);

	    /* make sure this is flagged as a ZFS group */
	    if (group != NULL)
		ret = sa_set_group_attr(group, "zfs", "true");
	}
	if (group != NULL) {
	    if (proto != NULL) {
		optionset = sa_get_optionset(group, proto);
		if (optionset == NULL) {
		    optionset = sa_create_optionset(group, proto);
		} else {
		    char **protolist;
		    int numprotos, i;
		    numprotos = sa_get_protocols(&protolist);
		    for (i = 0; i < numprotos; i++) {
			optionset = sa_create_optionset(group, protolist[i]);
		    }
		    if (protolist != NULL)
			free(protolist);
		}
	    }
	}
	if (err != NULL)
	    *err = ret;
	return (group);
}

/*
 * find_or_create_zfs_subgroup(groupname, optstring, *err)
 *
 * ZFS shares will be in a subgroup of the "zfs" master group.  This
 * function looks to see if the groupname exists and returns it if it
 * does or else creates a new one with the specified name and returns
 * that.  The "zfs" group will exist before we get here, but we make
 * sure just in case.
 *
 * err must be a valid pointer.
 */

static sa_group_t
find_or_create_zfs_subgroup(char *groupname, char *optstring, int *err)
{
	sa_group_t group = NULL;
	sa_group_t zfs;
	char *name;
	char *options;

	/* start with the top-level "zfs" group */
	zfs = sa_get_group("zfs");
	*err = SA_OK;
	if (zfs != NULL) {
	    for (group = sa_get_sub_group(zfs); group != NULL;
		group = sa_get_next_group(group)) {
		name = sa_get_group_attr(group, "name");
		if (name != NULL && strcmp(name, groupname) == 0) {
		    /* have the group so break out of here */
		    sa_free_attr_string(name);
		    break;
		}
		if (name != NULL)
		    sa_free_attr_string(name);
	    }

	    if (group == NULL) {
		/* need to create the sub-group since it doesn't exist */
		group = _sa_create_zfs_group(zfs, groupname);
		if (group != NULL) {
		    set_node_attr(group, "zfs", "true");
		}
		if (strcmp(optstring, "on") == 0)
		    optstring = "rw";
		if (group != NULL) {
		    options = strdup(optstring);
		    if (options != NULL) {
			*err = sa_parse_legacy_options(group, options, "nfs");
			free(options);
		    } else {
			*err = SA_NO_MEMORY;
		    }
		}
	    }
	}
	return (group);
}

/*
 * sa_get_zfs_shares(groupname)
 *
 * Walk the mnttab for all zfs mounts and determine which are
 * shared. Find or create the appropriate group/sub-group to contain
 * the shares.
 *
 * All shares are in a sub-group that will hold the properties. This
 * allows representing the inherited property model.
 */

int
sa_get_zfs_shares(char *groupname)
{
	sa_group_t group;
	sa_group_t zfsgroup;
	int legacy = 0;
	int err;
	zfs_handle_t **zlist;
	char shareopts[ZFS_MAXPROPLEN];
	sa_share_t share;
	zfs_source_t source;
	char sourcestr[ZFS_MAXPROPLEN];
	char mountpoint[ZFS_MAXPROPLEN];
	char *options;
	size_t count = 0, i;

	/*
	 * if we can't access libzfs, don't bother doing anything.
	 */
	if (zfs_libhandle == NULL)
	    return (SA_SYSTEM_ERR);

	zfsgroup = find_or_create_group(groupname, "nfs", &err);
	if (zfsgroup != NULL) {
		/*
		 * need to walk the mounted ZFS pools and datasets to
		 * find shares that are possible.
		 */
	    get_all_filesystems(&zlist, &count);
	    qsort(zlist, count, sizeof (void *), mountpoint_compare);

	    group = zfsgroup;
	    for (i = 0; i < count; i++) {
		char *dataset;

		source = ZFS_SRC_ALL;
		if (zfs_prop_get(zlist[i], ZFS_PROP_MOUNTPOINT, mountpoint,
					sizeof (mountpoint), NULL, NULL, 0,
					B_FALSE) != 0) {
		    /* no mountpoint */
		    continue;
		}

		/*
		 * zfs_get_name value must not be freed. It is just a
		 * pointer to a value in the handle.
		 */
		if ((dataset = (char *)zfs_get_name(zlist[i])) == NULL)
		    continue;

		/*
		 * only deal with "mounted" file systems since
		 * unmounted file systems can't actually be shared.
		 */

		if (!zfs_is_mounted(zlist[i], NULL))
		    continue;

		if (zfs_prop_get(zlist[i], ZFS_PROP_SHARENFS, shareopts,
					sizeof (shareopts), &source, sourcestr,
					ZFS_MAXPROPLEN,
					B_FALSE) == 0 &&
			strcmp(shareopts, "off") != 0) {
		    /* it is shared so add to list */
		    share = sa_find_share(mountpoint);
		    err = SA_OK;
		    if (share != NULL) {
			/*
			 * A zfs file system had been shared
			 * through traditional methods
			 * (share/dfstab or added to a non-zfs
			 * group.  Now it has been added to a
			 * ZFS group via the zfs
			 * command. Remove from previous
			 * config and setup with current
			 * options.
			 */
			err = sa_remove_share(share);
			share = NULL;
		    }
		    if (err == SA_OK) {
			if (source & ZFS_SRC_INHERITED) {
			    int doshopt = 0;
			/*
			 * Need to find the "real" parent
			 * sub-group. It may not be mounted, but it
			 * was identified in the "sourcestr"
			 * variable. The real parent not mounted can
			 * occur if "canmount=off and sharenfs=on".
			 */
			    group = find_or_create_zfs_subgroup(sourcestr,
							shareopts, &doshopt);
			    if (group != NULL) {
				share = _sa_add_share(group, mountpoint,
							SA_SHARE_TRANSIENT,
							&err);
				/*
				 * some options may only be on
				 * shares. If the opt string
				 * contains one of those, we
				 * put it just on the share.
				 */
				if (share != NULL &&
				    doshopt == SA_PROP_SHARE_ONLY) {
				    options = strdup(shareopts);
				    if (options != NULL) {
					err = sa_parse_legacy_options(share,
								options, "nfs");
					free(options);
				    }
				}
			    } else {
				err = SA_NO_MEMORY;
			    }
			} else {
			    group = _sa_create_zfs_group(zfsgroup, dataset);
			    if (group == NULL) {
				static int err = 0;
				/*
				 * there is a problem, but we can't do
				 * anything about it at this point so
				 * we issue a warning an move on.
				 */
				if (err == 0) {
				    /* only print error once */
				    (void) fprintf(stderr,
					gettext("Cannot create ZFS subgroup "
						"during initialization:"
						" %s\n"),
					sa_errorstr(SA_SYSTEM_ERR));
				    err = 1;
				}
				continue;
			    }
			    set_node_attr(group, "zfs", "true");
			    share = _sa_add_share(group, mountpoint,
						SA_SHARE_TRANSIENT, &err);
			    if (err == SA_OK) {
				if (strcmp(shareopts, "on") != 0) {
				    options = strdup(shareopts);
				    if (options != NULL) {
					err = sa_parse_legacy_options(group,
									options,
									"nfs");
					free(options);
				    }
				    if (err == SA_PROP_SHARE_ONLY) {
					/*
					 * Same as above, some
					 * properties may only be on
					 * shares, but due to the ZFS
					 * sub-groups being
					 * artificial, we sometimes
					 * get this and have to deal
					 * with it. We do it by
					 * attempting to put it on the
					 * share.
					 */
					options = strdup(shareopts);
					if (options != NULL)
					    err = sa_parse_legacy_options(
									share,
									options,
									"nfs");
					    free(options);
					}
				    /* unmark the share's changed state */
				    set_node_attr(share, "changed", NULL);
				}
			    }
			}
		    }
		}
	    }
	}
	/*
	 * Don't need to free the "zlist" variable since it is only a
	 * pointer to a cached value that will be freed when
	 * sa_fini() is called.
	 */
	return (legacy);
}

#define	COMMAND		"/usr/sbin/zfs"

/*
 * sa_zfs_set_sharenfs(group, path, on)
 *
 * Update the "sharenfs" property on the path. If on is true, then set
 * to the properties on the group or "on" if no properties are
 * defined. Set to "off" if on is false.
 */

int
sa_zfs_set_sharenfs(sa_group_t group, char *path, int on)
{
	int ret = SA_NOT_IMPLEMENTED;
	char *command;

	command = malloc(ZFS_MAXPROPLEN * 2);
	if (command != NULL) {
	    char *opts = NULL;
	    char *dataset;
	    FILE *pfile;
	    /* for now, NFS is always available for "zfs" */
	    if (on) {
		opts = sa_proto_legacy_format("nfs", group, 1);
		if (opts != NULL && strlen(opts) == 0) {
		    free(opts);
		    opts = strdup("on");
		}
	    }
	    dataset = get_zfs_dataset(path);
	    if (dataset != NULL) {
		(void) snprintf(command, ZFS_MAXPROPLEN * 2,
				"%s set sharenfs=\"%s\" %s", COMMAND,
				opts != NULL ? opts : "off",
				dataset);
		pfile = popen(command, "r");
		if (pfile != NULL) {
		    ret = pclose(pfile);
		    if (ret != 0)
			ret = SA_SYSTEM_ERR;
		}
	    }
	    if (opts != NULL)
		free(opts);
	    if (dataset != NULL)
		free(dataset);
	    free(command);
	}
	return (ret);
}

/*
 * sa_zfs_update(group)
 *
 * call back to ZFS to update the share if necessary.
 * Don't do it if it isn't a real change.
 */
int
sa_zfs_update(sa_group_t group)
{
	sa_optionset_t protopt;
	sa_group_t parent;
	char *command;
	char *optstring;
	int ret = SA_OK;
	int doupdate = 0;
	FILE *pfile;

	if (sa_is_share(group))
	    parent = sa_get_parent_group(group);
	else
	    parent = group;

	if (parent != NULL) {
	    command = malloc(ZFS_MAXPROPLEN * 2);
	    if (command == NULL)
		return (SA_NO_MEMORY);

	    *command = '\0';
	    for (protopt = sa_get_optionset(parent, NULL); protopt != NULL;
		protopt = sa_get_next_optionset(protopt)) {

		char *proto = sa_get_optionset_attr(protopt, "type");
		char *path;
		char *dataset = NULL;
		char *zfsopts = NULL;

		if (sa_is_share(group)) {
		    path = sa_get_share_attr((sa_share_t)group, "path");
		    if (path != NULL) {
			dataset = get_zfs_dataset(path);
			sa_free_attr_string(path);
		    }
		} else {
		    dataset = sa_get_group_attr(group, "name");
		}
		/* update only when there is an optstring found */
		doupdate = 0;
		if (proto != NULL && dataset != NULL) {
		    optstring = sa_proto_legacy_format(proto, group, 1);
		    zfsopts = get_zfs_property(dataset, ZFS_PROP_SHARENFS);

		    if (optstring != NULL && zfsopts != NULL) {
			if (strcmp(optstring, zfsopts) != 0)
			    doupdate++;
		    }

		    if (doupdate) {
			if (optstring != NULL && strlen(optstring) > 0) {
			    (void) snprintf(command, ZFS_MAXPROPLEN * 2,
					    "%s set sharenfs=%s %s", COMMAND,
					    optstring, dataset);
			} else {
			    (void) snprintf(command, ZFS_MAXPROPLEN * 2,
					    "%s set sharenfs=on %s", COMMAND,
					    dataset);
			}
			pfile = popen(command, "r");
			if (pfile != NULL)
			    ret = pclose(pfile);
			switch (ret) {
			default:
			case 1:
			    ret = SA_SYSTEM_ERR;
			    break;
			case 2:
			    ret = SA_SYNTAX_ERR;
			    break;
			case 0:
			    break;
			}
		    }
		    if (optstring != NULL) {
			free(optstring);
		    }
		    if (zfsopts != NULL)
			free(zfsopts);
		}
		if (proto != NULL)
		    sa_free_attr_string(proto);
		if (dataset != NULL)
		    free(dataset);
	    }
	    free(command);
	}
	return (ret);
}

/*
 * sa_group_is_zfs(group)
 *
 * Given the group, determine if the zfs attribute is set.
 */

int
sa_group_is_zfs(sa_group_t group)
{
	char *zfs;
	int ret = 0;

	zfs = sa_get_group_attr(group, "zfs");
	if (zfs != NULL) {
	    ret = 1;
	    sa_free_attr_string(zfs);
	}
	return (ret);
}

/*
 * sa_path_is_zfs(path)
 *
 * Check to see if the file system path represents is of type "zfs".
 */

int
sa_path_is_zfs(char *path)
{
	char *fstype;
	int ret = 0;

	fstype = sa_fstype(path);
	if (fstype != NULL && strcmp(fstype, "zfs") == 0) {
	    ret = 1;
	}
	if (fstype != NULL)
	    sa_free_fstype(fstype);
	return (ret);
}