1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * 9P Client Definitions
4  *
5  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
6  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
7  */
8 
9 #ifndef NET_9P_CLIENT_H
10 #define NET_9P_CLIENT_H
11 
12 #include <linux/utsname.h>
13 #include <linux/idr.h>
14 #include <linux/tracepoint-defs.h>
15 
16 /* Number of requests per row */
17 #define P9_ROW_MAXTAG 255
18 
19 /** enum p9_proto_versions - 9P protocol versions
20  * @p9_proto_legacy: 9P Legacy mode, pre-9P2000.u
21  * @p9_proto_2000u: 9P2000.u extension
22  * @p9_proto_2000L: 9P2000.L extension
23  */
24 
25 enum p9_proto_versions {
26 	p9_proto_legacy,
27 	p9_proto_2000u,
28 	p9_proto_2000L,
29 };
30 
31 
32 /**
33  * enum p9_trans_status - different states of underlying transports
34  * @Connected: transport is connected and healthy
35  * @Disconnected: transport has been disconnected
36  * @Hung: transport is connected by wedged
37  *
38  * This enumeration details the various states a transport
39  * instatiation can be in.
40  */
41 
42 enum p9_trans_status {
43 	Connected,
44 	BeginDisconnect,
45 	Disconnected,
46 	Hung,
47 };
48 
49 /**
50  * enum p9_req_status_t - status of a request
51  * @REQ_STATUS_ALLOC: request has been allocated but not sent
52  * @REQ_STATUS_UNSENT: request waiting to be sent
53  * @REQ_STATUS_SENT: request sent to server
54  * @REQ_STATUS_RCVD: response received from server
55  * @REQ_STATUS_FLSHD: request has been flushed
56  * @REQ_STATUS_ERROR: request encountered an error on the client side
57  */
58 
59 enum p9_req_status_t {
60 	REQ_STATUS_ALLOC,
61 	REQ_STATUS_UNSENT,
62 	REQ_STATUS_SENT,
63 	REQ_STATUS_RCVD,
64 	REQ_STATUS_FLSHD,
65 	REQ_STATUS_ERROR,
66 };
67 
68 /**
69  * struct p9_req_t - request slots
70  * @status: status of this request slot
71  * @t_err: transport error
72  * @wq: wait_queue for the client to block on for this request
73  * @tc: the request fcall structure
74  * @rc: the response fcall structure
75  * @req_list: link for higher level objects to chain requests
76  */
77 struct p9_req_t {
78 	int status;
79 	int t_err;
80 	refcount_t refcount;
81 	wait_queue_head_t wq;
82 	struct p9_fcall tc;
83 	struct p9_fcall rc;
84 	struct list_head req_list;
85 };
86 
87 /**
88  * struct p9_client - per client instance state
89  * @lock: protect @fids and @reqs
90  * @msize: maximum data size negotiated by protocol
91  * @proto_version: 9P protocol version to use
92  * @trans_mod: module API instantiated with this client
93  * @status: connection state
94  * @trans: tranport instance state and API
95  * @fids: All active FID handles
96  * @reqs: All active requests.
97  * @name: node name used as client id
98  *
99  * The client structure is used to keep track of various per-client
100  * state that has been instantiated.
101  */
102 struct p9_client {
103 	spinlock_t lock;
104 	unsigned int msize;
105 	unsigned char proto_version;
106 	struct p9_trans_module *trans_mod;
107 	enum p9_trans_status status;
108 	void *trans;
109 	struct kmem_cache *fcall_cache;
110 
111 	union {
112 		struct {
113 			int rfd;
114 			int wfd;
115 		} fd;
116 		struct {
117 			u16 port;
118 			bool privport;
119 
120 		} tcp;
121 	} trans_opts;
122 
123 	struct idr fids;
124 	struct idr reqs;
125 
126 	char name[__NEW_UTS_LEN + 1];
127 };
128 
129 /**
130  * struct p9_fid - file system entity handle
131  * @clnt: back pointer to instantiating &p9_client
132  * @fid: numeric identifier for this handle
133  * @mode: current mode of this fid (enum?)
134  * @qid: the &p9_qid server identifier this handle points to
135  * @iounit: the server reported maximum transaction size for this file
136  * @uid: the numeric uid of the local user who owns this handle
137  * @rdir: readdir accounting structure (allocated on demand)
138  * @dlist: per-dentry fid tracking
139  *
140  * TODO: This needs lots of explanation.
141  */
142 enum fid_source {
143 	FID_FROM_OTHER,
144 	FID_FROM_INODE,
145 	FID_FROM_DENTRY,
146 };
147 
148 struct p9_fid {
149 	struct p9_client *clnt;
150 	u32 fid;
151 	refcount_t count;
152 	int mode;
153 	struct p9_qid qid;
154 	u32 iounit;
155 	kuid_t uid;
156 
157 	void *rdir;
158 
159 	struct hlist_node dlist;	/* list of all fids attached to a dentry */
160 	struct hlist_node ilist;
161 };
162 
163 /**
164  * struct p9_dirent - directory entry structure
165  * @qid: The p9 server qid for this dirent
166  * @d_off: offset to the next dirent
167  * @d_type: type of file
168  * @d_name: file name
169  */
170 
171 struct p9_dirent {
172 	struct p9_qid qid;
173 	u64 d_off;
174 	unsigned char d_type;
175 	char d_name[256];
176 };
177 
178 struct iov_iter;
179 
180 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt);
181 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb);
182 int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid,
183 		     const char *name);
184 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
185 		       struct p9_fid *newdirfid, const char *new_name);
186 struct p9_client *p9_client_create(const char *dev_name, char *options);
187 void p9_client_destroy(struct p9_client *clnt);
188 void p9_client_disconnect(struct p9_client *clnt);
189 void p9_client_begin_disconnect(struct p9_client *clnt);
190 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
191 				const char *uname, kuid_t n_uname, const char *aname);
192 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
193 		const unsigned char * const *wnames, int clone);
194 int p9_client_open(struct p9_fid *fid, int mode);
195 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
196 							char *extension);
197 int p9_client_link(struct p9_fid *fid, struct p9_fid *oldfid, const char *newname);
198 int p9_client_symlink(struct p9_fid *fid, const char *name, const char *symname,
199 		kgid_t gid, struct p9_qid *qid);
200 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
201 		kgid_t gid, struct p9_qid *qid);
202 int p9_client_clunk(struct p9_fid *fid);
203 int p9_client_fsync(struct p9_fid *fid, int datasync);
204 int p9_client_remove(struct p9_fid *fid);
205 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags);
206 int p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err);
207 int p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
208 		int *err);
209 int p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err);
210 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
211 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
212 		  struct p9_dirent *dirent);
213 struct p9_wstat *p9_client_stat(struct p9_fid *fid);
214 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
215 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *attr);
216 
217 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
218 							u64 request_mask);
219 
220 int p9_client_mknod_dotl(struct p9_fid *oldfid, const char *name, int mode,
221 			dev_t rdev, kgid_t gid, struct p9_qid *qid);
222 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
223 				kgid_t gid, struct p9_qid *qid);
224 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status);
225 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *fl);
226 void p9_fcall_fini(struct p9_fcall *fc);
227 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag);
228 
p9_req_get(struct p9_req_t * r)229 static inline void p9_req_get(struct p9_req_t *r)
230 {
231 	refcount_inc(&r->refcount);
232 }
233 
p9_req_try_get(struct p9_req_t * r)234 static inline int p9_req_try_get(struct p9_req_t *r)
235 {
236 	return refcount_inc_not_zero(&r->refcount);
237 }
238 
239 int p9_req_put(struct p9_client *c, struct p9_req_t *r);
240 
241 /* We cannot have the real tracepoints in header files,
242  * use a wrapper function */
243 DECLARE_TRACEPOINT(9p_fid_ref);
244 void do_trace_9p_fid_get(struct p9_fid *fid);
245 void do_trace_9p_fid_put(struct p9_fid *fid);
246 
247 /* fid reference counting helpers:
248  *  - fids used for any length of time should always be referenced through
249  *    p9_fid_get(), and released with p9_fid_put()
250  *  - v9fs_fid_lookup() or similar will automatically call get for you
251  *    and also require a put
252  *  - the *_fid_add() helpers will stash the fid in the inode,
253  *    at which point it is the responsibility of evict_inode()
254  *    to call the put
255  *  - the last put will automatically send a clunk to the server
256  */
p9_fid_get(struct p9_fid * fid)257 static inline struct p9_fid *p9_fid_get(struct p9_fid *fid)
258 {
259 	if (tracepoint_enabled(9p_fid_ref))
260 		do_trace_9p_fid_get(fid);
261 
262 	refcount_inc(&fid->count);
263 
264 	return fid;
265 }
266 
p9_fid_put(struct p9_fid * fid)267 static inline int p9_fid_put(struct p9_fid *fid)
268 {
269 	if (!fid || IS_ERR(fid))
270 		return 0;
271 
272 	if (tracepoint_enabled(9p_fid_ref))
273 		do_trace_9p_fid_put(fid);
274 
275 	if (!refcount_dec_and_test(&fid->count))
276 		return 0;
277 
278 	return p9_client_clunk(fid);
279 }
280 
281 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
282 
283 int p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
284 		    int16_t *tag, int rewind);
285 int p9stat_read(struct p9_client *clnt, char *buf, int len,
286 		struct p9_wstat *st);
287 void p9stat_free(struct p9_wstat *stbuf);
288 
289 int p9_is_proto_dotu(struct p9_client *clnt);
290 int p9_is_proto_dotl(struct p9_client *clnt);
291 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
292 				   const char *attr_name, u64 *attr_size);
293 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
294 			  u64 attr_size, int flags);
295 int p9_client_readlink(struct p9_fid *fid, char **target);
296 
297 int p9_client_init(void);
298 void p9_client_exit(void);
299 
300 #endif /* NET_9P_CLIENT_H */
301