1/*-
2 * Copyright (c) 2017 Juniper Networks, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
25 */
26/*-
27 * 9P filesystem subroutines. This file consists of all the Non VFS subroutines.
28 * It contains all of the functions related to the driver submission which form
29 * the upper layer i.e, p9fs driver. This will interact with the client to make
30 * sure we have correct API calls in the header.
31 */
32
33#include <sys/cdefs.h>
34#include <sys/systm.h>
35#include <sys/limits.h>
36#include <sys/mount.h>
37#include <sys/sysctl.h>
38#include <sys/vnode.h>
39
40#include "p9fs_proto.h"
41
42#include <fs/p9fs/p9_client.h>
43#include <fs/p9fs/p9_debug.h>
44#include <fs/p9fs/p9_protocol.h>
45#include <fs/p9fs/p9fs.h>
46
47int
48p9fs_proto_dotl(struct p9fs_session *vses)
49{
50
51	return (vses->flags & P9FS_PROTO_2000L);
52}
53
54/* Initialize a p9fs session */
55struct p9_fid *
56p9fs_init_session(struct mount *mp, int *error)
57{
58	struct p9fs_session *vses;
59	struct p9fs_mount *virtmp;
60	struct p9_fid *fid;
61	char *access;
62
63	virtmp = VFSTOP9(mp);
64	vses = &virtmp->p9fs_session;
65	vses->uid = P9_NONUNAME;
66	vses->uname = P9_DEFUNAME;
67	vses->aname = P9_DEFANAME;
68
69	/*
70	 * Create the client structure. Call into the driver to create
71	 * driver structures for the actual IO transfer.
72	 */
73	vses->clnt = p9_client_create(mp, error, virtmp->mount_tag);
74
75	if (vses->clnt == NULL) {
76		P9_DEBUG(ERROR, "%s: p9_client_create failed\n", __func__);
77		return (NULL);
78	}
79	/*
80	 * Find the client version and cache the copy. We will use this copy
81	 * throughout FS layer.
82	 */
83	if (p9_is_proto_dotl(vses->clnt))
84		vses->flags |= P9FS_PROTO_2000L;
85	else if (p9_is_proto_dotu(vses->clnt))
86		vses->flags |= P9FS_PROTO_2000U;
87
88	/* Set the access mode */
89	access = vfs_getopts(mp->mnt_optnew, "access", error);
90	if (access == NULL)
91		vses->flags |= P9_ACCESS_USER;
92	else if (!strcmp(access, "any"))
93		vses->flags |= P9_ACCESS_ANY;
94	else if (!strcmp(access, "single"))
95		vses->flags |= P9_ACCESS_SINGLE;
96	else if (!strcmp(access, "user"))
97		vses->flags |= P9_ACCESS_USER;
98	else {
99		P9_DEBUG(ERROR, "%s: unknown access mode\n", __func__);
100		*error = EINVAL;
101		goto out;
102	}
103
104	*error = 0;
105	/* Attach with the backend host*/
106	fid = p9_client_attach(vses->clnt, NULL, vses->uname, P9_NONUNAME,
107	    vses->aname, error);
108	vses->mnt_fid = fid;
109
110	if (*error != 0) {
111		P9_DEBUG(ERROR, "%s: attach failed: %d\n", __func__, *error);
112		goto out;
113	}
114	P9_DEBUG(SUBR, "%s: attach successful fid :%p\n", __func__, fid);
115	fid->uid = vses->uid;
116
117	/* initialize the node list for the session */
118	STAILQ_INIT(&vses->virt_node_list);
119	P9FS_LOCK_INIT(vses);
120
121	P9_DEBUG(SUBR, "%s: INIT session successful\n", __func__);
122
123	return (fid);
124out:
125	p9_client_destroy(vses->clnt);
126	return (NULL);
127}
128
129/* Begin to terminate a session */
130void
131p9fs_prepare_to_close(struct mount *mp)
132{
133	struct p9fs_session *vses;
134	struct p9fs_mount *vmp;
135	struct p9fs_node *np, *pnp, *tmp;
136
137	vmp = VFSTOP9(mp);
138	vses = &vmp->p9fs_session;
139
140	/* break the node->parent references */
141	STAILQ_FOREACH_SAFE(np, &vses->virt_node_list, p9fs_node_next, tmp) {
142		if (np->parent && np->parent != np) {
143			pnp = np->parent;
144			np->parent = NULL;
145			vrele(P9FS_NTOV(pnp));
146		}
147	}
148
149	/* We are about to teardown, we dont allow anything other than clunk after this.*/
150	p9_client_begin_disconnect(vses->clnt);
151}
152
153/* Shutdown a session */
154void
155p9fs_complete_close(struct mount *mp)
156{
157	struct p9fs_session *vses;
158	struct p9fs_mount *vmp;
159
160	vmp = VFSTOP9(mp);
161	vses = &vmp->p9fs_session;
162
163	/* Finish the close*/
164	p9_client_disconnect(vses->clnt);
165}
166
167
168/* Call from unmount. Close the session. */
169void
170p9fs_close_session(struct mount *mp)
171{
172	struct p9fs_session *vses;
173	struct p9fs_mount *vmp;
174
175	vmp = VFSTOP9(mp);
176	vses = &vmp->p9fs_session;
177
178	p9fs_complete_close(mp);
179	/* Clean up the clnt structure. */
180	p9_client_destroy(vses->clnt);
181	P9FS_LOCK_DESTROY(vses);
182	P9_DEBUG(SUBR, "%s: Clean close session .\n", __func__);
183}
184
185/*
186 * Remove all the fids of a particular type from a p9fs node
187 * as well as destroy/clunk them.
188 */
189void
190p9fs_fid_remove_all(struct p9fs_node *np, int leave_ofids)
191{
192	struct p9_fid *fid, *tfid;
193
194	STAILQ_FOREACH_SAFE(fid, &np->vfid_list, fid_next, tfid) {
195		STAILQ_REMOVE(&np->vfid_list, fid, p9_fid, fid_next);
196		p9_client_clunk(fid);
197	}
198
199	if (!leave_ofids) {
200		STAILQ_FOREACH_SAFE(fid, &np->vofid_list, fid_next, tfid) {
201			STAILQ_REMOVE(&np->vofid_list, fid, p9_fid, fid_next);
202			p9_client_clunk(fid);
203		}
204	}
205}
206
207
208/* Remove a fid from its corresponding fid list */
209void
210p9fs_fid_remove(struct p9fs_node *np, struct p9_fid *fid, int fid_type)
211{
212
213	switch (fid_type) {
214	case VFID:
215		P9FS_VFID_LOCK(np);
216		STAILQ_REMOVE(&np->vfid_list, fid, p9_fid, fid_next);
217		P9FS_VFID_UNLOCK(np);
218		break;
219	case VOFID:
220		P9FS_VOFID_LOCK(np);
221		STAILQ_REMOVE(&np->vofid_list, fid, p9_fid, fid_next);
222		P9FS_VOFID_UNLOCK(np);
223		break;
224	}
225}
226
227/* Add a fid to the corresponding fid list */
228void
229p9fs_fid_add(struct p9fs_node *np, struct p9_fid *fid, int fid_type)
230{
231
232	switch (fid_type) {
233	case VFID:
234		P9FS_VFID_LOCK(np);
235		STAILQ_INSERT_TAIL(&np->vfid_list, fid, fid_next);
236		P9FS_VFID_UNLOCK(np);
237		break;
238	case VOFID:
239		P9FS_VOFID_LOCK(np);
240		STAILQ_INSERT_TAIL(&np->vofid_list, fid, fid_next);
241		P9FS_VOFID_UNLOCK(np);
242		break;
243	}
244}
245
246/* Build the path from root to current directory */
247static int
248p9fs_get_full_path(struct p9fs_node *np, char ***names)
249{
250	int i, n;
251	struct p9fs_node *node;
252	char **wnames;
253
254	n = 0;
255	for (node = np ; (node != NULL) && !IS_ROOT(node) ; node = node->parent)
256		n++;
257
258	if (node == NULL)
259		return (0);
260
261	wnames = malloc(n * sizeof(char *), M_TEMP, M_ZERO|M_WAITOK);
262
263	for (i = n-1, node = np; i >= 0 ; i--, node = node->parent)
264		wnames[i] = node->inode.i_name;
265
266	*names = wnames;
267	return (n);
268}
269
270/*
271 * Return TRUE if this fid can be used for the requested mode.
272 */
273static int
274p9fs_compatible_mode(struct p9_fid *fid, int mode)
275{
276	/*
277	 * Return TRUE for an exact match. For OREAD and OWRITE, allow
278	 * existing ORDWR fids to match. Only check the low two bits
279	 * of mode.
280	 *
281	 * TODO: figure out if this is correct for O_APPEND
282	 */
283	int fid_mode = fid->mode & 3;
284	if (fid_mode == mode)
285		return (TRUE);
286	if (fid_mode == P9PROTO_ORDWR)
287		return (mode == P9PROTO_OREAD || mode == P9PROTO_OWRITE);
288	return (FALSE);
289}
290
291/*
292 * Retrieve fid structure corresponding to a particular
293 * uid and fid type for a p9fs node
294 */
295static struct p9_fid *
296p9fs_get_fid_from_uid(struct p9fs_node *np, uid_t uid, int fid_type, int mode)
297{
298	struct p9_fid *fid;
299
300	switch (fid_type) {
301	case VFID:
302		P9FS_VFID_LOCK(np);
303		STAILQ_FOREACH(fid, &np->vfid_list, fid_next) {
304			if (fid->uid == uid) {
305				P9FS_VFID_UNLOCK(np);
306				return (fid);
307			}
308		}
309		P9FS_VFID_UNLOCK(np);
310		break;
311	case VOFID:
312		P9FS_VOFID_LOCK(np);
313		STAILQ_FOREACH(fid, &np->vofid_list, fid_next) {
314			if (fid->uid == uid && p9fs_compatible_mode(fid, mode)) {
315				P9FS_VOFID_UNLOCK(np);
316				return (fid);
317			}
318		}
319		P9FS_VOFID_UNLOCK(np);
320		break;
321	}
322
323	return (NULL);
324}
325
326/*
327 * Function returns the fid sturcture for a file corresponding to current user id.
328 * First it searches in the fid list of the corresponding p9fs node.
329 * New fid will be created if not already present and added in the corresponding
330 * fid list in the p9fs node.
331 * If the user is not already attached then this will attach the user first
332 * and then create a new fid for this particular file by doing dir walk.
333 */
334struct p9_fid *
335p9fs_get_fid(struct p9_client *clnt, struct p9fs_node *np, struct ucred *cred,
336    int fid_type, int mode, int *error)
337{
338	uid_t uid;
339	struct p9_fid *fid, *oldfid;
340	struct p9fs_node *root;
341	struct p9fs_session *vses;
342	int i, l, clone;
343	char **wnames = NULL;
344	uint16_t nwnames;
345
346	oldfid = NULL;
347	vses = np->p9fs_ses;
348
349	if (vses->flags & P9_ACCESS_ANY)
350		uid = vses->uid;
351	else if (cred)
352		uid = cred->cr_uid;
353	else
354		uid = 0;
355
356	/*
357	 * Search for the fid in corresponding fid list.
358	 * We should return NULL for VOFID if it is not present in the list.
359	 * Because VOFID should have been created during the file open.
360	 * If VFID is not present in the list then we should create one.
361	 */
362	fid = p9fs_get_fid_from_uid(np, uid, fid_type, mode);
363	if (fid != NULL || fid_type == VOFID)
364		return (fid);
365
366	/* Check root if the user is attached */
367	root = &np->p9fs_ses->rnp;
368	fid = p9fs_get_fid_from_uid(root, uid, fid_type, mode);
369	if(fid == NULL) {
370		/* Attach the user */
371		fid = p9_client_attach(clnt, NULL, NULL, uid,
372		    vses->aname, error);
373		if (*error != 0)
374			return (NULL);
375		p9fs_fid_add(root, fid, fid_type);
376	}
377
378	/* If we are looking for root then return it */
379	if (IS_ROOT(np))
380		return (fid);
381
382	/* Get full path from root to p9fs node */
383	nwnames = p9fs_get_full_path(np, &wnames);
384
385	/*
386	 * Could not get full path.
387	 * If p9fs node is not deleted, parent should exist.
388	 */
389	KASSERT(nwnames != 0, ("%s: Directory of %s doesn't exist", __func__, np->inode.i_name));
390
391	clone = 1;
392	i = 0;
393	while (i < nwnames) {
394		l = MIN(nwnames - i, P9_MAXWELEM);
395
396		fid = p9_client_walk(fid, l, wnames, clone, error);
397		if (*error != 0) {
398			if (oldfid)
399				p9_client_clunk(oldfid);
400			fid = NULL;
401			goto bail_out;
402		}
403		oldfid = fid;
404		clone = 0;
405		i += l ;
406	}
407	p9fs_fid_add(np, fid, fid_type);
408bail_out:
409	free(wnames, M_TEMP);
410	return (fid);
411}
412