// SPDX-License-Identifier: LGPL-3.0-or-later
/*
 * vim:noexpandtab:shiftwidth=8:tabstop=8:
 *
 * Copyright CEA/DAM/DIF  (2011)
 * contributeur : Philippe DENIEL   philippe.deniel@cea.fr
 *                Thomas LEIBOVICI  thomas.leibovici@cea.fr
 *
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * ---------------------------------------
 */

/**
 * \file    9p_attach.c
 * \brief   9P version
 *
 * 9p_attach.c : _9P_interpretor, request ATTACH
 *
 *
 */

#include "config.h"
#include <stdio.h>
#include <string.h>
#include <pthread.h>
#include "nfs_core.h"
#include "export_mgr.h"
#include "log.h"
#include "fsal.h"
#include "nfs_exports.h"
#include "9p.h"

int _9p_attach(struct _9p_request_data *req9p, u32 *plenout, char *preply)
{
	char *cursor = req9p->_9pmsg + _9P_HDR_SIZE + _9P_TYPE_SIZE;
	u16 *msgtag = NULL;
	u32 *fid = NULL;
	u32 *afid = NULL;
	u16 *uname_len = NULL;
	char *uname_str = NULL;
	u16 *aname_len = NULL;
	char *aname_str = NULL;
	u32 *n_uname = NULL;
	u32 err = 0;

	struct _9p_fid *pfid = NULL;

	fsal_status_t fsal_status;
	char exppath[MAXPATHLEN+1];
	int port;
	struct gsh_export *export;

	/* Get data */
	_9p_getptr(cursor, msgtag, u16);
	_9p_getptr(cursor, fid, u32);
	_9p_getptr(cursor, afid, u32);
	_9p_getstr(cursor, uname_len, uname_str);
	_9p_getstr(cursor, aname_len, aname_str);
	_9p_getptr(cursor, n_uname, u32);

	LogDebug(COMPONENT_9P,
		 "TATTACH: tag=%u fid=%u afid=%d uname='%.*s' aname='%.*s' n_uname=%d",
		 (u32) *msgtag, *fid, *afid, (int) *uname_len, uname_str,
		 (int) *aname_len, aname_str, *n_uname);

	if (*fid >= _9P_FID_PER_CONN) {
		err = ERANGE;
		goto errout;
	}

	/*
	 * Find the export for the aname (using as well Path or Tag)
	 *
	 * Keep it in the op_ctx.
	 */
	if (*aname_len >= sizeof(exppath)) {
		err = ENAMETOOLONG;
		goto errout;
	}

	_9p_get_fname(exppath, *aname_len, aname_str);

	/*  Find the export for the dirname (using as well Path, Pseudo, or Tag)
	 */
	if (exppath[0] != '/') {
		LogFullDebug(COMPONENT_9P,
			     "Searching for export by tag for %s",
			     exppath);
		export = get_gsh_export_by_tag(exppath);
	} else if (nfs_param.core_param.mount_path_pseudo) {
		LogFullDebug(COMPONENT_9P,
			     "Searching for export by pseudo for %s",
			     exppath);
		export = get_gsh_export_by_pseudo(exppath, false);
	} else {
		LogFullDebug(COMPONENT_9P,
			     "Searching for export by path for %s",
			     exppath);
		export = get_gsh_export_by_path(exppath, false);
	}

	/* Did we find something ? */
	if (export == NULL) {
		err = ENOENT;
		goto errout;
	}

	/* Fill in more of the op_ctx */
	set_op_context_export(export);
	op_ctx->caller_addr = &req9p->pconn->addrpeer;

	/* check export_perms. */
	export_check_access();

	if ((op_ctx->export_perms.options & EXPORT_OPTION_9P) == 0) {
		LogInfo(COMPONENT_9P,
			"9P is not allowed for this export entry, rejecting client");
		err = EACCES;
		goto errout;
	}

	port = get_port(&req9p->pconn->addrpeer);

	if (op_ctx->export_perms.options & EXPORT_OPTION_PRIVILEGED_PORT &&
	    port >= IPPORT_RESERVED) {
		LogInfo(COMPONENT_9P,
			"Port %d is too high for this export entry, rejecting client",
			port);
		err = EACCES;
		goto errout;
	}

	/* Set export and fid id in fid */
	pfid = gsh_calloc(1, sizeof(struct _9p_fid));

	/* Copy the export into the pfid with reference. */
	pfid->fid_export = op_ctx->ctx_export;
	get_gsh_export_ref(pfid->fid_export);

	pfid->fid = *fid;
	req9p->pconn->fids[*fid] = pfid;

	/* Is user name provided as a string or as an uid ? */
	if (*n_uname != _9P_NONUNAME) {
		/* Build the fid creds */
		err = _9p_tools_get_req_context_by_uid(*n_uname, pfid);
		if (err != 0) {
			err = -err;
			goto errout;
		}
	} else if (*uname_len != 0) {
		/* Build the fid creds */
		err = _9p_tools_get_req_context_by_name(*uname_len, uname_str,
							pfid);
		if (err != 0) {
			err = -err;
			goto errout;
		}
	} else {
		/* No n_uname nor uname */
		err = EINVAL;
		goto errout;
	}

	if (exppath[0] != '/') {
		/* The client used the Tag. Use the export root object is
		 * correctly set, fetch it, and take an LRU reference.
		 */
		fsal_status = nfs_export_get_root_entry(op_ctx->ctx_export,
							&pfid->pentry);
	} else {
		/* Note that we call this even if exppath is just the path to
		 * the export. It resolves that efficiently.
		 */
		fsal_status = fsal_lookup_path(exppath, &pfid->pentry);
	}

	if (FSAL_IS_ERROR(fsal_status)) {
		err = _9p_tools_errno(fsal_status);
		goto errout;
	}

	/* Initialize state_t embedded in fid. The refcount is initialized
	 * to one to represent the state_t being embedded in the fid. This
	 * prevents it from ever being reduced to zero by dec_state_t_ref.
	 */
	pfid->state =
		op_ctx->fsal_export->exp_ops.alloc_state(op_ctx->fsal_export,
							 STATE_TYPE_9P_FID,
							 NULL);

	glist_init(&pfid->state->state_data.fid.state_locklist);
	pfid->state->state_refcount = 1;

	/* Compute the qid */
	pfid->qid.type = _9P_QTDIR;
	pfid->qid.version = 0;	/* No cache, we want the client
				 * to stay synchronous with the server */
	pfid->qid.path = pfid->pentry->fileid;
	pfid->xattr = NULL;

	/* Build the reply */
	_9p_setinitptr(cursor, preply, _9P_RATTACH);
	_9p_setptr(cursor, msgtag, u16);

	_9p_setqid(cursor, pfid->qid);

	_9p_setendptr(cursor, preply);
	_9p_checkbound(cursor, preply, plenout);

	LogDebug(COMPONENT_9P,
		 "RATTACH: tag=%u fid=%u qid=(type=%u,version=%u,path=%llu)",
		 *msgtag, *fid, (u32) pfid->qid.type, pfid->qid.version,
		 (unsigned long long)pfid->qid.path);

	return 1;

errout:

	_9p_release_opctx();

	if (pfid != NULL)
		free_fid(pfid);

	return _9p_rerror(req9p, msgtag, err, plenout, preply);
}
