xref: /openbmc/qemu/hw/9pfs/cofs.c (revision d341d9f3) 
1 
2 /*
3  * Virtio 9p backend
4  *
5  * Copyright IBM, Corp. 2011
6  *
7  * Authors:
8  *  Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
9  *
10  * This work is licensed under the terms of the GNU GPL, version 2.  See
11  * the COPYING file in the top-level directory.
12  *
13  */
14 
15 #include "fsdev/qemu-fsdev.h"
16 #include "qemu/thread.h"
17 #include "qemu/coroutine.h"
18 #include "coth.h"
19 
20 static ssize_t __readlink(V9fsState *s, V9fsPath *path, V9fsString *buf)
21 {
22     ssize_t len, maxlen = PATH_MAX;
23 
24     buf->data = g_malloc(PATH_MAX);
25     for(;;) {
26         len = s->ops->readlink(&s->ctx, path, buf->data, maxlen);
27         if (len < 0) {
28             g_free(buf->data);
29             buf->data = NULL;
30             buf->size = 0;
31             break;
32         } else if (len == maxlen) {
33             /*
34              * We dodn't have space to put the NULL or we have more
35              * to read. Increase the size and try again
36              */
37             maxlen *= 2;
38             g_free(buf->data);
39             buf->data = g_malloc(maxlen);
40             continue;
41         }
42         /*
43          * Null terminate the readlink output
44          */
45         buf->data[len] = '\0';
46         buf->size = len;
47         break;
48     }
49     return len;
50 }
51 
52 int v9fs_co_readlink(V9fsPDU *pdu, V9fsPath *path, V9fsString *buf)
53 {
54     int err;
55     V9fsState *s = pdu->s;
56 
57     if (v9fs_request_cancelled(pdu)) {
58         return -EINTR;
59     }
60     v9fs_path_read_lock(s);
61     v9fs_co_run_in_worker(
62         {
63             err = __readlink(s, path, buf);
64             if (err < 0) {
65                 err = -errno;
66             }
67         });
68     v9fs_path_unlock(s);
69     return err;
70 }
71 
72 int v9fs_co_statfs(V9fsPDU *pdu, V9fsPath *path, struct statfs *stbuf)
73 {
74     int err;
75     V9fsState *s = pdu->s;
76 
77     if (v9fs_request_cancelled(pdu)) {
78         return -EINTR;
79     }
80     v9fs_path_read_lock(s);
81     v9fs_co_run_in_worker(
82         {
83             err = s->ops->statfs(&s->ctx, path, stbuf);
84             if (err < 0) {
85                 err = -errno;
86             }
87         });
88     v9fs_path_unlock(s);
89     return err;
90 }
91 
92 int v9fs_co_chmod(V9fsPDU *pdu, V9fsPath *path, mode_t mode)
93 {
94     int err;
95     FsCred cred;
96     V9fsState *s = pdu->s;
97 
98     if (v9fs_request_cancelled(pdu)) {
99         return -EINTR;
100     }
101     cred_init(&cred);
102     cred.fc_mode = mode;
103     v9fs_path_read_lock(s);
104     v9fs_co_run_in_worker(
105         {
106             err = s->ops->chmod(&s->ctx, path, &cred);
107             if (err < 0) {
108                 err = -errno;
109             }
110         });
111     v9fs_path_unlock(s);
112     return err;
113 }
114 
115 int v9fs_co_utimensat(V9fsPDU *pdu, V9fsPath *path,
116                       struct timespec times[2])
117 {
118     int err;
119     V9fsState *s = pdu->s;
120 
121     if (v9fs_request_cancelled(pdu)) {
122         return -EINTR;
123     }
124     v9fs_path_read_lock(s);
125     v9fs_co_run_in_worker(
126         {
127             err = s->ops->utimensat(&s->ctx, path, times);
128             if (err < 0) {
129                 err = -errno;
130             }
131         });
132     v9fs_path_unlock(s);
133     return err;
134 }
135 
136 int v9fs_co_chown(V9fsPDU *pdu, V9fsPath *path, uid_t uid, gid_t gid)
137 {
138     int err;
139     FsCred cred;
140     V9fsState *s = pdu->s;
141 
142     if (v9fs_request_cancelled(pdu)) {
143         return -EINTR;
144     }
145     cred_init(&cred);
146     cred.fc_uid = uid;
147     cred.fc_gid = gid;
148     v9fs_path_read_lock(s);
149     v9fs_co_run_in_worker(
150         {
151             err = s->ops->chown(&s->ctx, path, &cred);
152             if (err < 0) {
153                 err = -errno;
154             }
155         });
156     v9fs_path_unlock(s);
157     return err;
158 }
159 
160 int v9fs_co_truncate(V9fsPDU *pdu, V9fsPath *path, off_t size)
161 {
162     int err;
163     V9fsState *s = pdu->s;
164 
165     if (v9fs_request_cancelled(pdu)) {
166         return -EINTR;
167     }
168     v9fs_path_read_lock(s);
169     v9fs_co_run_in_worker(
170         {
171             err = s->ops->truncate(&s->ctx, path, size);
172             if (err < 0) {
173                 err = -errno;
174             }
175         });
176     v9fs_path_unlock(s);
177     return err;
178 }
179 
180 int v9fs_co_mknod(V9fsPDU *pdu, V9fsFidState *fidp, V9fsString *name, uid_t uid,
181                   gid_t gid, dev_t dev, mode_t mode, struct stat *stbuf)
182 {
183     int err;
184     V9fsPath path;
185     FsCred cred;
186     V9fsState *s = pdu->s;
187 
188     if (v9fs_request_cancelled(pdu)) {
189         return -EINTR;
190     }
191     cred_init(&cred);
192     cred.fc_uid  = uid;
193     cred.fc_gid  = gid;
194     cred.fc_mode = mode;
195     cred.fc_rdev = dev;
196     v9fs_path_read_lock(s);
197     v9fs_co_run_in_worker(
198         {
199             err = s->ops->mknod(&s->ctx, &fidp->path, name->data, &cred);
200             if (err < 0) {
201                 err = -errno;
202             } else {
203                 v9fs_path_init(&path);
204                 err = v9fs_name_to_path(s, &fidp->path, name->data, &path);
205                 if (!err) {
206                     err = s->ops->lstat(&s->ctx, &path, stbuf);
207                     if (err < 0) {
208                         err = -errno;
209                     }
210                 }
211                 v9fs_path_free(&path);
212             }
213         });
214     v9fs_path_unlock(s);
215     return err;
216 }
217 
218 /* Only works with path name based fid */
219 int v9fs_co_remove(V9fsPDU *pdu, V9fsPath *path)
220 {
221     int err;
222     V9fsState *s = pdu->s;
223 
224     if (v9fs_request_cancelled(pdu)) {
225         return -EINTR;
226     }
227     v9fs_path_read_lock(s);
228     v9fs_co_run_in_worker(
229         {
230             err = s->ops->remove(&s->ctx, path->data);
231             if (err < 0) {
232                 err = -errno;
233             }
234         });
235     v9fs_path_unlock(s);
236     return err;
237 }
238 
239 int v9fs_co_unlinkat(V9fsPDU *pdu, V9fsPath *path, V9fsString *name, int flags)
240 {
241     int err;
242     V9fsState *s = pdu->s;
243 
244     if (v9fs_request_cancelled(pdu)) {
245         return -EINTR;
246     }
247     v9fs_path_read_lock(s);
248     v9fs_co_run_in_worker(
249         {
250             err = s->ops->unlinkat(&s->ctx, path, name->data, flags);
251             if (err < 0) {
252                 err = -errno;
253             }
254         });
255     v9fs_path_unlock(s);
256     return err;
257 }
258 
259 /* Only work with path name based fid */
260 int v9fs_co_rename(V9fsPDU *pdu, V9fsPath *oldpath, V9fsPath *newpath)
261 {
262     int err;
263     V9fsState *s = pdu->s;
264 
265     if (v9fs_request_cancelled(pdu)) {
266         return -EINTR;
267     }
268     v9fs_co_run_in_worker(
269         {
270             err = s->ops->rename(&s->ctx, oldpath->data, newpath->data);
271             if (err < 0) {
272                 err = -errno;
273             }
274         });
275     return err;
276 }
277 
278 int v9fs_co_renameat(V9fsPDU *pdu, V9fsPath *olddirpath, V9fsString *oldname,
279                      V9fsPath *newdirpath, V9fsString *newname)
280 {
281     int err;
282     V9fsState *s = pdu->s;
283 
284     if (v9fs_request_cancelled(pdu)) {
285         return -EINTR;
286     }
287     v9fs_co_run_in_worker(
288         {
289             err = s->ops->renameat(&s->ctx, olddirpath, oldname->data,
290                                    newdirpath, newname->data);
291             if (err < 0) {
292                 err = -errno;
293             }
294         });
295     return err;
296 }
297 
298 int v9fs_co_symlink(V9fsPDU *pdu, V9fsFidState *dfidp, V9fsString *name,
299                     const char *oldpath, gid_t gid, struct stat *stbuf)
300 {
301     int err;
302     FsCred cred;
303     V9fsPath path;
304     V9fsState *s = pdu->s;
305 
306     if (v9fs_request_cancelled(pdu)) {
307         return -EINTR;
308     }
309     cred_init(&cred);
310     cred.fc_uid = dfidp->uid;
311     cred.fc_gid = gid;
312     cred.fc_mode = 0777;
313     v9fs_path_read_lock(s);
314     v9fs_co_run_in_worker(
315         {
316             err = s->ops->symlink(&s->ctx, oldpath, &dfidp->path,
317                                   name->data, &cred);
318             if (err < 0) {
319                 err = -errno;
320             } else {
321                 v9fs_path_init(&path);
322                 err = v9fs_name_to_path(s, &dfidp->path, name->data, &path);
323                 if (!err) {
324                     err = s->ops->lstat(&s->ctx, &path, stbuf);
325                     if (err < 0) {
326                         err = -errno;
327                     }
328                 }
329                 v9fs_path_free(&path);
330             }
331         });
332     v9fs_path_unlock(s);
333     return err;
334 }
335 
336 /*
337  * For path name based fid we don't block. So we can
338  * directly call the fs driver ops.
339  */
340 int v9fs_co_name_to_path(V9fsPDU *pdu, V9fsPath *dirpath,
341                          const char *name, V9fsPath *path)
342 {
343     int err;
344     V9fsState *s = pdu->s;
345 
346     if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
347         err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
348         if (err < 0) {
349             err = -errno;
350         }
351     } else {
352         if (v9fs_request_cancelled(pdu)) {
353             return -EINTR;
354         }
355         v9fs_co_run_in_worker(
356             {
357                 err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
358                 if (err < 0) {
359                     err = -errno;
360                 }
361             });
362     }
363     return err;
364 }
365