include/net/9p/client.h

   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 struct netfs_io_subrequest;
 211 void p9_client_write_subreq(struct netfs_io_subrequest *subreq);
 212 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
 213 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
 214                   struct p9_dirent *dirent);
 215 struct p9_wstat *p9_client_stat(struct p9_fid *fid);
 216 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
 217 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *attr);
 218
 219 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
 220                                                         u64 request_mask);
 221
 222 int p9_client_mknod_dotl(struct p9_fid *oldfid, const char *name, int mode,
 223                         dev_t rdev, kgid_t gid, struct p9_qid *qid);
 224 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
 225                                 kgid_t gid, struct p9_qid *qid);
 226 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status);
 227 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *fl);
 228 void p9_fcall_fini(struct p9_fcall *fc);
 229 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag);
 230
 231 static inline void p9_req_get(struct p9_req_t *r)
 232 {
 233         refcount_inc(&r->refcount);
 234 }
 235
 236 static inline int p9_req_try_get(struct p9_req_t *r)
 237 {
 238         return refcount_inc_not_zero(&r->refcount);
 239 }
 240
 241 int p9_req_put(struct p9_client *c, struct p9_req_t *r);
 242
 243 /* We cannot have the real tracepoints in header files,
 244  * use a wrapper function */
 245 DECLARE_TRACEPOINT(9p_fid_ref);
 246 void do_trace_9p_fid_get(struct p9_fid *fid);
 247 void do_trace_9p_fid_put(struct p9_fid *fid);
 248
 249 /* fid reference counting helpers:
 250  *  - fids used for any length of time should always be referenced through
 251  *    p9_fid_get(), and released with p9_fid_put()
 252  *  - v9fs_fid_lookup() or similar will automatically call get for you
 253  *    and also require a put
 254  *  - the *_fid_add() helpers will stash the fid in the inode,
 255  *    at which point it is the responsibility of evict_inode()
 256  *    to call the put
 257  *  - the last put will automatically send a clunk to the server
 258  */
 259 static inline struct p9_fid *p9_fid_get(struct p9_fid *fid)
 260 {
 261         if (tracepoint_enabled(9p_fid_ref))
 262                 do_trace_9p_fid_get(fid);
 263
 264         refcount_inc(&fid->count);
 265
 266         return fid;
 267 }
 268
 269 static inline int p9_fid_put(struct p9_fid *fid)
 270 {
 271         if (!fid || IS_ERR(fid))
 272                 return 0;
 273
 274         if (tracepoint_enabled(9p_fid_ref))
 275                 do_trace_9p_fid_put(fid);
 276
 277         if (!refcount_dec_and_test(&fid->count))
 278                 return 0;
 279
 280         return p9_client_clunk(fid);
 281 }
 282
 283 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
 284
 285 int p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
 286                     int16_t *tag, int rewind);
 287 int p9stat_read(struct p9_client *clnt, char *buf, int len,
 288                 struct p9_wstat *st);
 289 void p9stat_free(struct p9_wstat *stbuf);
 290
 291 int p9_is_proto_dotu(struct p9_client *clnt);
 292 int p9_is_proto_dotl(struct p9_client *clnt);
 293 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
 294                                    const char *attr_name, u64 *attr_size);
 295 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
 296                           u64 attr_size, int flags);
 297 int p9_client_readlink(struct p9_fid *fid, char **target);
 298
 299 int p9_client_init(void);
 300 void p9_client_exit(void);
 301
 302 #endif /* NET_9P_CLIENT_H */