xref: /openbmc/qemu/hw/9pfs/9p.h (revision 5242ef88) 
1 #ifndef QEMU_9P_H
2 #define QEMU_9P_H
3 
4 #include <dirent.h>
5 #include <utime.h>
6 #include <sys/resource.h>
7 #include "fsdev/file-op-9p.h"
8 #include "fsdev/9p-iov-marshal.h"
9 #include "qemu/thread.h"
10 #include "qemu/coroutine.h"
11 #include "qemu/qht.h"
12 
13 enum {
14     P9_TLERROR = 6,
15     P9_RLERROR,
16     P9_TSTATFS = 8,
17     P9_RSTATFS,
18     P9_TLOPEN = 12,
19     P9_RLOPEN,
20     P9_TLCREATE = 14,
21     P9_RLCREATE,
22     P9_TSYMLINK = 16,
23     P9_RSYMLINK,
24     P9_TMKNOD = 18,
25     P9_RMKNOD,
26     P9_TRENAME = 20,
27     P9_RRENAME,
28     P9_TREADLINK = 22,
29     P9_RREADLINK,
30     P9_TGETATTR = 24,
31     P9_RGETATTR,
32     P9_TSETATTR = 26,
33     P9_RSETATTR,
34     P9_TXATTRWALK = 30,
35     P9_RXATTRWALK,
36     P9_TXATTRCREATE = 32,
37     P9_RXATTRCREATE,
38     P9_TREADDIR = 40,
39     P9_RREADDIR,
40     P9_TFSYNC = 50,
41     P9_RFSYNC,
42     P9_TLOCK = 52,
43     P9_RLOCK,
44     P9_TGETLOCK = 54,
45     P9_RGETLOCK,
46     P9_TLINK = 70,
47     P9_RLINK,
48     P9_TMKDIR = 72,
49     P9_RMKDIR,
50     P9_TRENAMEAT = 74,
51     P9_RRENAMEAT,
52     P9_TUNLINKAT = 76,
53     P9_RUNLINKAT,
54     P9_TVERSION = 100,
55     P9_RVERSION,
56     P9_TAUTH = 102,
57     P9_RAUTH,
58     P9_TATTACH = 104,
59     P9_RATTACH,
60     P9_TERROR = 106,
61     P9_RERROR,
62     P9_TFLUSH = 108,
63     P9_RFLUSH,
64     P9_TWALK = 110,
65     P9_RWALK,
66     P9_TOPEN = 112,
67     P9_ROPEN,
68     P9_TCREATE = 114,
69     P9_RCREATE,
70     P9_TREAD = 116,
71     P9_RREAD,
72     P9_TWRITE = 118,
73     P9_RWRITE,
74     P9_TCLUNK = 120,
75     P9_RCLUNK,
76     P9_TREMOVE = 122,
77     P9_RREMOVE,
78     P9_TSTAT = 124,
79     P9_RSTAT,
80     P9_TWSTAT = 126,
81     P9_RWSTAT,
82 };
83 
84 
85 /* qid.types */
86 enum {
87     P9_QTDIR = 0x80,
88     P9_QTAPPEND = 0x40,
89     P9_QTEXCL = 0x20,
90     P9_QTMOUNT = 0x10,
91     P9_QTAUTH = 0x08,
92     P9_QTTMP = 0x04,
93     P9_QTSYMLINK = 0x02,
94     P9_QTLINK = 0x01,
95     P9_QTFILE = 0x00,
96 };
97 
98 typedef enum P9ProtoVersion {
99     V9FS_PROTO_2000U = 0x01,
100     V9FS_PROTO_2000L = 0x02,
101 } P9ProtoVersion;
102 
103 /*
104  * Minimum message size supported by this 9pfs server.
105  *
106  * A client establishes a session by sending a Tversion request along with a
107  * 'msize' parameter which suggests the server a maximum message size ever to be
108  * used for communication (for both requests and replies) between client and
109  * server during that session. If client suggests a 'msize' smaller than this
110  * value then session is denied by server with an error response.
111  */
112 #define P9_MIN_MSIZE    4096
113 
114 #define P9_NOTAG    UINT16_MAX
115 #define P9_NOFID    UINT32_MAX
116 #define P9_MAXWELEM 16
117 
118 #define FID_REFERENCED          0x1
119 #define FID_NON_RECLAIMABLE     0x2
120 static inline char *rpath(FsContext *ctx, const char *path)
121 {
122     return g_strdup_printf("%s/%s", ctx->fs_root, path);
123 }
124 
125 /*
126  * ample room for Twrite/Rread header
127  * size[4] Tread/Twrite tag[2] fid[4] offset[8] count[4]
128  */
129 #define P9_IOHDRSZ 24
130 
131 typedef struct V9fsPDU V9fsPDU;
132 typedef struct V9fsState V9fsState;
133 typedef struct V9fsTransport V9fsTransport;
134 
135 typedef struct {
136     uint32_t size_le;
137     uint8_t id;
138     uint16_t tag_le;
139 } QEMU_PACKED P9MsgHeader;
140 /* According to the specification, 9p messages start with a 7-byte header.
141  * Since most of the code uses this header size in literal form, we must be
142  * sure this is indeed the case.
143  */
144 QEMU_BUILD_BUG_ON(sizeof(P9MsgHeader) != 7);
145 
146 struct V9fsPDU {
147     uint32_t size;
148     uint16_t tag;
149     uint8_t id;
150     uint8_t cancelled;
151     CoQueue complete;
152     V9fsState *s;
153     QLIST_ENTRY(V9fsPDU) next;
154     uint32_t idx;
155 };
156 
157 
158 /* FIXME
159  * 1) change user needs to set groups and stuff
160  */
161 
162 #define MAX_REQ         128
163 #define MAX_TAG_LEN     32
164 
165 #define BUG_ON(cond) assert(!(cond))
166 
167 typedef struct V9fsFidState V9fsFidState;
168 
169 enum {
170     P9_FID_NONE = 0,
171     P9_FID_FILE,
172     P9_FID_DIR,
173     P9_FID_XATTR,
174 };
175 
176 typedef struct V9fsConf
177 {
178     /* tag name for the device */
179     char *tag;
180     char *fsdev_id;
181 } V9fsConf;
182 
183 /* 9p2000.L xattr flags (matches Linux values) */
184 #define P9_XATTR_CREATE 1
185 #define P9_XATTR_REPLACE 2
186 
187 typedef struct V9fsXattr
188 {
189     uint64_t copied_len;
190     uint64_t len;
191     void *value;
192     V9fsString name;
193     int flags;
194     bool xattrwalk_fid;
195 } V9fsXattr;
196 
197 typedef struct V9fsDir {
198     DIR *stream;
199     P9ProtoVersion proto_version;
200     /* readdir mutex type used for 9P2000.u protocol variant */
201     CoMutex readdir_mutex_u;
202     /* readdir mutex type used for 9P2000.L protocol variant */
203     QemuMutex readdir_mutex_L;
204 } V9fsDir;
205 
206 static inline void v9fs_readdir_lock(V9fsDir *dir)
207 {
208     if (dir->proto_version == V9FS_PROTO_2000U) {
209         qemu_co_mutex_lock(&dir->readdir_mutex_u);
210     } else {
211         qemu_mutex_lock(&dir->readdir_mutex_L);
212     }
213 }
214 
215 static inline void v9fs_readdir_unlock(V9fsDir *dir)
216 {
217     if (dir->proto_version == V9FS_PROTO_2000U) {
218         qemu_co_mutex_unlock(&dir->readdir_mutex_u);
219     } else {
220         qemu_mutex_unlock(&dir->readdir_mutex_L);
221     }
222 }
223 
224 static inline void v9fs_readdir_init(P9ProtoVersion proto_version, V9fsDir *dir)
225 {
226     dir->proto_version = proto_version;
227     if (proto_version == V9FS_PROTO_2000U) {
228         qemu_co_mutex_init(&dir->readdir_mutex_u);
229     } else {
230         qemu_mutex_init(&dir->readdir_mutex_L);
231     }
232 }
233 
234 /*
235  * Type for 9p fs drivers' (a.k.a. 9p backends) result of readdir requests,
236  * which is a chained list of directory entries.
237  */
238 typedef struct V9fsDirEnt {
239     /* mandatory (must not be NULL) information for all readdir requests */
240     struct dirent *dent;
241     /*
242      * optional (may be NULL): A full stat of each directory entry is just
243      * done if explicitly told to fs driver.
244      */
245     struct stat *st;
246     /*
247      * instead of an array, directory entries are always returned as
248      * chained list, that's because the amount of entries retrieved by fs
249      * drivers is dependent on the individual entries' name (since response
250      * messages are size limited), so the final amount cannot be estimated
251      * before hand
252      */
253     struct V9fsDirEnt *next;
254 } V9fsDirEnt;
255 
256 /*
257  * Filled by fs driver on open and other
258  * calls.
259  */
260 union V9fsFidOpenState {
261     int fd;
262     V9fsDir dir;
263     V9fsXattr xattr;
264     /*
265      * private pointer for fs drivers, that
266      * have its own internal representation of
267      * open files.
268      */
269     void *private;
270 };
271 
272 struct V9fsFidState {
273     int fid_type;
274     int32_t fid;
275     V9fsPath path;
276     V9fsFidOpenState fs;
277     V9fsFidOpenState fs_reclaim;
278     int flags;
279     int open_flags;
280     uid_t uid;
281     int ref;
282     bool clunked;
283     QSIMPLEQ_ENTRY(V9fsFidState) next;
284     QSLIST_ENTRY(V9fsFidState) reclaim_next;
285 };
286 
287 typedef enum AffixType_t {
288     AffixType_Prefix,
289     AffixType_Suffix, /* A.k.a. postfix. */
290 } AffixType_t;
291 
292 /*
293  * Unique affix of variable length.
294  *
295  * An affix is (currently) either a suffix or a prefix, which is either
296  * going to be prepended (prefix) or appended (suffix) with some other
297  * number for the goal to generate unique numbers. Accordingly the
298  * suffixes (or prefixes) we generate @b must all have the mathematical
299  * property of being suffix-free (or prefix-free in case of prefixes)
300  * so that no matter what number we concatenate the affix with, that we
301  * always reliably get unique numbers as result after concatenation.
302  */
303 typedef struct VariLenAffix {
304     AffixType_t type; /* Whether this affix is a suffix or a prefix. */
305     uint64_t value; /* Actual numerical value of this affix. */
306     /*
307      * Lenght of the affix, that is how many (of the lowest) bits of ``value``
308      * must be used for appending/prepending this affix to its final resulting,
309      * unique number.
310      */
311     int bits;
312 } VariLenAffix;
313 
314 /* See qid_inode_prefix_hash_bits(). */
315 typedef struct {
316     dev_t dev; /* FS device on host. */
317     /*
318      * How many (high) bits of the original inode number shall be used for
319      * hashing.
320      */
321     int prefix_bits;
322 } QpdEntry;
323 
324 /* QID path prefix entry, see stat_to_qid */
325 typedef struct {
326     dev_t dev;
327     uint16_t ino_prefix;
328     uint32_t qp_affix_index;
329     VariLenAffix qp_affix;
330 } QppEntry;
331 
332 /* QID path full entry, as above */
333 typedef struct {
334     dev_t dev;
335     ino_t ino;
336     uint64_t path;
337 } QpfEntry;
338 
339 struct V9fsState {
340     QLIST_HEAD(, V9fsPDU) free_list;
341     QLIST_HEAD(, V9fsPDU) active_list;
342     QSIMPLEQ_HEAD(, V9fsFidState) fid_list;
343     FileOperations *ops;
344     FsContext ctx;
345     char *tag;
346     P9ProtoVersion proto_version;
347     int32_t msize;
348     V9fsPDU pdus[MAX_REQ];
349     const V9fsTransport *transport;
350     /*
351      * lock ensuring atomic path update
352      * on rename.
353      */
354     CoRwlock rename_lock;
355     int32_t root_fid;
356     Error *migration_blocker;
357     V9fsConf fsconf;
358     struct stat root_st;
359     dev_t dev_id;
360     struct qht qpd_table;
361     struct qht qpp_table;
362     struct qht qpf_table;
363     uint64_t qp_ndevices; /* Amount of entries in qpd_table. */
364     uint16_t qp_affix_next;
365     uint64_t qp_fullpath_next;
366 };
367 
368 /* 9p2000.L open flags */
369 #define P9_DOTL_RDONLY        00000000
370 #define P9_DOTL_WRONLY        00000001
371 #define P9_DOTL_RDWR          00000002
372 #define P9_DOTL_NOACCESS      00000003
373 #define P9_DOTL_CREATE        00000100
374 #define P9_DOTL_EXCL          00000200
375 #define P9_DOTL_NOCTTY        00000400
376 #define P9_DOTL_TRUNC         00001000
377 #define P9_DOTL_APPEND        00002000
378 #define P9_DOTL_NONBLOCK      00004000
379 #define P9_DOTL_DSYNC         00010000
380 #define P9_DOTL_FASYNC        00020000
381 #define P9_DOTL_DIRECT        00040000
382 #define P9_DOTL_LARGEFILE     00100000
383 #define P9_DOTL_DIRECTORY     00200000
384 #define P9_DOTL_NOFOLLOW      00400000
385 #define P9_DOTL_NOATIME       01000000
386 #define P9_DOTL_CLOEXEC       02000000
387 #define P9_DOTL_SYNC          04000000
388 
389 /* 9p2000.L at flags */
390 #define P9_DOTL_AT_REMOVEDIR         0x200
391 
392 /* 9P2000.L lock type */
393 #define P9_LOCK_TYPE_RDLCK 0
394 #define P9_LOCK_TYPE_WRLCK 1
395 #define P9_LOCK_TYPE_UNLCK 2
396 
397 #define P9_LOCK_SUCCESS 0
398 #define P9_LOCK_BLOCKED 1
399 #define P9_LOCK_ERROR 2
400 #define P9_LOCK_GRACE 3
401 
402 #define P9_LOCK_FLAGS_BLOCK 1
403 #define P9_LOCK_FLAGS_RECLAIM 2
404 
405 typedef struct V9fsFlock
406 {
407     uint8_t type;
408     uint32_t flags;
409     uint64_t start; /* absolute offset */
410     uint64_t length;
411     uint32_t proc_id;
412     V9fsString client_id;
413 } V9fsFlock;
414 
415 typedef struct V9fsGetlock
416 {
417     uint8_t type;
418     uint64_t start; /* absolute offset */
419     uint64_t length;
420     uint32_t proc_id;
421     V9fsString client_id;
422 } V9fsGetlock;
423 
424 extern int open_fd_hw;
425 extern int total_open_fd;
426 
427 static inline void v9fs_path_write_lock(V9fsState *s)
428 {
429     if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
430         qemu_co_rwlock_wrlock(&s->rename_lock);
431     }
432 }
433 
434 static inline void v9fs_path_read_lock(V9fsState *s)
435 {
436     if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
437         qemu_co_rwlock_rdlock(&s->rename_lock);
438     }
439 }
440 
441 static inline void v9fs_path_unlock(V9fsState *s)
442 {
443     if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
444         qemu_co_rwlock_unlock(&s->rename_lock);
445     }
446 }
447 
448 static inline uint8_t v9fs_request_cancelled(V9fsPDU *pdu)
449 {
450     return pdu->cancelled;
451 }
452 
453 void coroutine_fn v9fs_reclaim_fd(V9fsPDU *pdu);
454 void v9fs_path_init(V9fsPath *path);
455 void v9fs_path_free(V9fsPath *path);
456 void v9fs_path_sprintf(V9fsPath *path, const char *fmt, ...);
457 void v9fs_path_copy(V9fsPath *dst, const V9fsPath *src);
458 size_t v9fs_readdir_response_size(V9fsString *name);
459 int v9fs_name_to_path(V9fsState *s, V9fsPath *dirpath,
460                       const char *name, V9fsPath *path);
461 int v9fs_device_realize_common(V9fsState *s, const V9fsTransport *t,
462                                Error **errp);
463 void v9fs_device_unrealize_common(V9fsState *s);
464 
465 V9fsPDU *pdu_alloc(V9fsState *s);
466 void pdu_free(V9fsPDU *pdu);
467 void pdu_submit(V9fsPDU *pdu, P9MsgHeader *hdr);
468 void v9fs_reset(V9fsState *s);
469 
470 struct V9fsTransport {
471     ssize_t     (*pdu_vmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt,
472                                 va_list ap);
473     ssize_t     (*pdu_vunmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt,
474                                   va_list ap);
475     void        (*init_in_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
476                                         unsigned int *pniov, size_t size);
477     void        (*init_out_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
478                                          unsigned int *pniov, size_t size);
479     void        (*push_and_notify)(V9fsPDU *pdu);
480 };
481 
482 #if defined(XATTR_SIZE_MAX)
483 /* Linux */
484 #define P9_XATTR_SIZE_MAX XATTR_SIZE_MAX
485 #elif defined(CONFIG_DARWIN)
486 /*
487  * Darwin doesn't seem to define a maximum xattr size in its user
488  * space header, so manually configure it across platforms as 64k.
489  *
490  * Having no limit at all can lead to QEMU crashing during large g_malloc()
491  * calls. Because QEMU does not currently support macOS guests, the below
492  * preliminary solution only works due to its being a reflection of the limit of
493  * Linux guests.
494  */
495 #define P9_XATTR_SIZE_MAX 65536
496 #else
497 #error Missing definition for P9_XATTR_SIZE_MAX for this host system
498 #endif
499 
500 #endif
501