xref: /qemu/hw/9pfs/cofs.c (revision d33717d7fca6a599aa991f771e3ea34b15978cee) 
1 /*
2  * 9p backend
3  *
4  * Copyright IBM, Corp. 2011
5  *
6  * Authors:
7  *  Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2.  See
10  * the COPYING file in the top-level directory.
11  *
12  */
13 
14 /*
15  * Not so fast! You might want to read the 9p developer docs first:
16  * https://wiki.qemu.org/Documentation/9p
17  */
18 
19 #include "qemu/osdep.h"
20 #include "fsdev/qemu-fsdev.h"
21 #include "qemu/thread.h"
22 #include "qemu/main-loop.h"
23 #include "coth.h"
24 
25 static ssize_t __readlink(V9fsState *s, V9fsPath *path, V9fsString *buf)
26 {
27     ssize_t len, maxlen = PATH_MAX;
28 
29     buf->data = g_malloc(PATH_MAX);
30     for (;;) {
31         len = s->ops->readlink(&s->ctx, path, buf->data, maxlen);
32         if (len < 0) {
33             g_free(buf->data);
34             buf->data = NULL;
35             buf->size = 0;
36             break;
37         } else if (len == maxlen) {
38             /*
39              * We dodn't have space to put the NULL or we have more
40              * to read. Increase the size and try again
41              */
42             maxlen *= 2;
43             g_free(buf->data);
44             buf->data = g_malloc(maxlen);
45             continue;
46         }
47         /*
48          * Null terminate the readlink output
49          */
50         buf->data[len] = '\0';
51         buf->size = len;
52         break;
53     }
54     return len;
55 }
56 
57 int coroutine_fn v9fs_co_readlink(V9fsPDU *pdu, V9fsPath *path, V9fsString *buf)
58 {
59     int err;
60     V9fsState *s = pdu->s;
61 
62     if (v9fs_request_cancelled(pdu)) {
63         return -EINTR;
64     }
65     v9fs_path_read_lock(s);
66     v9fs_co_run_in_worker(
67         {
68             err = __readlink(s, path, buf);
69             if (err < 0) {
70                 err = -errno;
71             }
72         });
73     v9fs_path_unlock(s);
74     return err;
75 }
76 
77 int coroutine_fn v9fs_co_statfs(V9fsPDU *pdu, V9fsPath *path,
78                                 struct statfs *stbuf)
79 {
80     int err;
81     V9fsState *s = pdu->s;
82 
83     if (v9fs_request_cancelled(pdu)) {
84         return -EINTR;
85     }
86     v9fs_path_read_lock(s);
87     v9fs_co_run_in_worker(
88         {
89             err = s->ops->statfs(&s->ctx, path, stbuf);
90             if (err < 0) {
91                 err = -errno;
92             }
93         });
94     v9fs_path_unlock(s);
95     return err;
96 }
97 
98 int coroutine_fn v9fs_co_chmod(V9fsPDU *pdu, V9fsPath *path, mode_t mode)
99 {
100     int err;
101     FsCred cred;
102     V9fsState *s = pdu->s;
103 
104     if (v9fs_request_cancelled(pdu)) {
105         return -EINTR;
106     }
107     cred_init(&cred);
108     cred.fc_mode = mode;
109     v9fs_path_read_lock(s);
110     v9fs_co_run_in_worker(
111         {
112             err = s->ops->chmod(&s->ctx, path, &cred);
113             if (err < 0) {
114                 err = -errno;
115             }
116         });
117     v9fs_path_unlock(s);
118     return err;
119 }
120 
121 int coroutine_fn v9fs_co_utimensat(V9fsPDU *pdu, V9fsPath *path,
122                                    struct timespec times[2])
123 {
124     int err;
125     V9fsState *s = pdu->s;
126 
127     if (v9fs_request_cancelled(pdu)) {
128         return -EINTR;
129     }
130     v9fs_path_read_lock(s);
131     v9fs_co_run_in_worker(
132         {
133             err = s->ops->utimensat(&s->ctx, path, times);
134             if (err < 0) {
135                 err = -errno;
136             }
137         });
138     v9fs_path_unlock(s);
139     return err;
140 }
141 
142 int coroutine_fn v9fs_co_futimens(V9fsPDU *pdu, V9fsFidState *fidp,
143                                   struct timespec times[2])
144 {
145     int err;
146     V9fsState *s = pdu->s;
147 
148     if (v9fs_request_cancelled(pdu)) {
149         return -EINTR;
150     }
151     v9fs_co_run_in_worker(
152         {
153             err = s->ops->futimens(&s->ctx, fidp->fid_type, &fidp->fs, times);
154             if (err < 0) {
155                 err = -errno;
156             }
157         });
158     return err;
159 }
160 
161 int coroutine_fn v9fs_co_chown(V9fsPDU *pdu, V9fsPath *path, uid_t uid,
162                                gid_t gid)
163 {
164     int err;
165     FsCred cred;
166     V9fsState *s = pdu->s;
167 
168     if (v9fs_request_cancelled(pdu)) {
169         return -EINTR;
170     }
171     cred_init(&cred);
172     cred.fc_uid = uid;
173     cred.fc_gid = gid;
174     v9fs_path_read_lock(s);
175     v9fs_co_run_in_worker(
176         {
177             err = s->ops->chown(&s->ctx, path, &cred);
178             if (err < 0) {
179                 err = -errno;
180             }
181         });
182     v9fs_path_unlock(s);
183     return err;
184 }
185 
186 int coroutine_fn v9fs_co_truncate(V9fsPDU *pdu, V9fsPath *path, off_t size)
187 {
188     int err;
189     V9fsState *s = pdu->s;
190 
191     if (v9fs_request_cancelled(pdu)) {
192         return -EINTR;
193     }
194     v9fs_path_read_lock(s);
195     v9fs_co_run_in_worker(
196         {
197             err = s->ops->truncate(&s->ctx, path, size);
198             if (err < 0) {
199                 err = -errno;
200             }
201         });
202     v9fs_path_unlock(s);
203     return err;
204 }
205 
206 int coroutine_fn v9fs_co_ftruncate(V9fsPDU *pdu, V9fsFidState *fidp, off_t size)
207 {
208     int err;
209     V9fsState *s = pdu->s;
210 
211     if (v9fs_request_cancelled(pdu)) {
212         return -EINTR;
213     }
214     v9fs_co_run_in_worker(
215         {
216             err = s->ops->ftruncate(&s->ctx, fidp->fid_type, &fidp->fs, size);
217             if (err < 0) {
218                 err = -errno;
219             }
220         });
221     return err;
222 }
223 
224 int coroutine_fn v9fs_co_mknod(V9fsPDU *pdu, V9fsFidState *fidp,
225                                V9fsString *name, uid_t uid, gid_t gid,
226                                dev_t dev, mode_t mode, struct stat *stbuf)
227 {
228     int err;
229     V9fsPath path;
230     FsCred cred;
231     V9fsState *s = pdu->s;
232 
233     if (v9fs_request_cancelled(pdu)) {
234         return -EINTR;
235     }
236     cred_init(&cred);
237     cred.fc_uid  = uid;
238     cred.fc_gid  = gid;
239     cred.fc_mode = mode;
240     cred.fc_rdev = dev;
241     v9fs_path_read_lock(s);
242     v9fs_co_run_in_worker(
243         {
244             err = s->ops->mknod(&s->ctx, &fidp->path, name->data, &cred);
245             if (err < 0) {
246                 err = -errno;
247             } else {
248                 v9fs_path_init(&path);
249                 err = v9fs_name_to_path(s, &fidp->path, name->data, &path);
250                 if (!err) {
251                     err = s->ops->lstat(&s->ctx, &path, stbuf);
252                     if (err < 0) {
253                         err = -errno;
254                     }
255                 }
256                 v9fs_path_free(&path);
257             }
258         });
259     v9fs_path_unlock(s);
260     return err;
261 }
262 
263 /* Only works with path name based fid */
264 int coroutine_fn v9fs_co_remove(V9fsPDU *pdu, V9fsPath *path)
265 {
266     int err;
267     V9fsState *s = pdu->s;
268 
269     if (v9fs_request_cancelled(pdu)) {
270         return -EINTR;
271     }
272     v9fs_path_read_lock(s);
273     v9fs_co_run_in_worker(
274         {
275             err = s->ops->remove(&s->ctx, path->data);
276             if (err < 0) {
277                 err = -errno;
278             }
279         });
280     v9fs_path_unlock(s);
281     return err;
282 }
283 
284 int coroutine_fn v9fs_co_unlinkat(V9fsPDU *pdu, V9fsPath *path,
285                                   V9fsString *name, int flags)
286 {
287     int err;
288     V9fsState *s = pdu->s;
289 
290     if (v9fs_request_cancelled(pdu)) {
291         return -EINTR;
292     }
293     v9fs_path_read_lock(s);
294     v9fs_co_run_in_worker(
295         {
296             err = s->ops->unlinkat(&s->ctx, path, name->data, flags);
297             if (err < 0) {
298                 err = -errno;
299             }
300         });
301     v9fs_path_unlock(s);
302     return err;
303 }
304 
305 /* Only work with path name based fid */
306 int coroutine_fn v9fs_co_rename(V9fsPDU *pdu, V9fsPath *oldpath,
307                                 V9fsPath *newpath)
308 {
309     int err;
310     V9fsState *s = pdu->s;
311 
312     if (v9fs_request_cancelled(pdu)) {
313         return -EINTR;
314     }
315     v9fs_co_run_in_worker(
316         {
317             err = s->ops->rename(&s->ctx, oldpath->data, newpath->data);
318             if (err < 0) {
319                 err = -errno;
320             }
321         });
322     return err;
323 }
324 
325 int coroutine_fn v9fs_co_renameat(V9fsPDU *pdu, V9fsPath *olddirpath,
326                                   V9fsString *oldname, V9fsPath *newdirpath,
327                                   V9fsString *newname)
328 {
329     int err;
330     V9fsState *s = pdu->s;
331 
332     if (v9fs_request_cancelled(pdu)) {
333         return -EINTR;
334     }
335     v9fs_co_run_in_worker(
336         {
337             err = s->ops->renameat(&s->ctx, olddirpath, oldname->data,
338                                    newdirpath, newname->data);
339             if (err < 0) {
340                 err = -errno;
341             }
342         });
343     return err;
344 }
345 
346 int coroutine_fn v9fs_co_symlink(V9fsPDU *pdu, V9fsFidState *dfidp,
347                                  V9fsString *name, const char *oldpath,
348                                  gid_t gid, struct stat *stbuf)
349 {
350     int err;
351     FsCred cred;
352     V9fsPath path;
353     V9fsState *s = pdu->s;
354 
355     if (v9fs_request_cancelled(pdu)) {
356         return -EINTR;
357     }
358     cred_init(&cred);
359     cred.fc_uid = dfidp->uid;
360     cred.fc_gid = gid;
361     cred.fc_mode = 0777;
362     v9fs_path_read_lock(s);
363     v9fs_co_run_in_worker(
364         {
365             err = s->ops->symlink(&s->ctx, oldpath, &dfidp->path,
366                                   name->data, &cred);
367             if (err < 0) {
368                 err = -errno;
369             } else {
370                 v9fs_path_init(&path);
371                 err = v9fs_name_to_path(s, &dfidp->path, name->data, &path);
372                 if (!err) {
373                     err = s->ops->lstat(&s->ctx, &path, stbuf);
374                     if (err < 0) {
375                         err = -errno;
376                     }
377                 }
378                 v9fs_path_free(&path);
379             }
380         });
381     v9fs_path_unlock(s);
382     return err;
383 }
384 
385 /*
386  * For path name based fid we don't block. So we can
387  * directly call the fs driver ops.
388  */
389 int coroutine_fn v9fs_co_name_to_path(V9fsPDU *pdu, V9fsPath *dirpath,
390                                       const char *name, V9fsPath *path)
391 {
392     int err;
393     V9fsState *s = pdu->s;
394 
395     if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
396         err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
397         if (err < 0) {
398             err = -errno;
399         }
400     } else {
401         if (v9fs_request_cancelled(pdu)) {
402             return -EINTR;
403         }
404         v9fs_co_run_in_worker(
405             {
406                 err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
407                 if (err < 0) {
408                     err = -errno;
409                 }
410             });
411     }
412     return err;
413 }
414