xref: /openbmc/qemu/hw/9pfs/cofs.c (revision 4a09d0bb)
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 #include "qemu/osdep.h"
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 coroutine_fn 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 coroutine_fn v9fs_co_statfs(V9fsPDU *pdu, V9fsPath *path,
73                                 struct statfs *stbuf)
74 {
75     int err;
76     V9fsState *s = pdu->s;
77 
78     if (v9fs_request_cancelled(pdu)) {
79         return -EINTR;
80     }
81     v9fs_path_read_lock(s);
82     v9fs_co_run_in_worker(
83         {
84             err = s->ops->statfs(&s->ctx, path, stbuf);
85             if (err < 0) {
86                 err = -errno;
87             }
88         });
89     v9fs_path_unlock(s);
90     return err;
91 }
92 
93 int coroutine_fn v9fs_co_chmod(V9fsPDU *pdu, V9fsPath *path, mode_t mode)
94 {
95     int err;
96     FsCred cred;
97     V9fsState *s = pdu->s;
98 
99     if (v9fs_request_cancelled(pdu)) {
100         return -EINTR;
101     }
102     cred_init(&cred);
103     cred.fc_mode = mode;
104     v9fs_path_read_lock(s);
105     v9fs_co_run_in_worker(
106         {
107             err = s->ops->chmod(&s->ctx, path, &cred);
108             if (err < 0) {
109                 err = -errno;
110             }
111         });
112     v9fs_path_unlock(s);
113     return err;
114 }
115 
116 int coroutine_fn v9fs_co_utimensat(V9fsPDU *pdu, V9fsPath *path,
117                                    struct timespec times[2])
118 {
119     int err;
120     V9fsState *s = pdu->s;
121 
122     if (v9fs_request_cancelled(pdu)) {
123         return -EINTR;
124     }
125     v9fs_path_read_lock(s);
126     v9fs_co_run_in_worker(
127         {
128             err = s->ops->utimensat(&s->ctx, path, times);
129             if (err < 0) {
130                 err = -errno;
131             }
132         });
133     v9fs_path_unlock(s);
134     return err;
135 }
136 
137 int coroutine_fn v9fs_co_chown(V9fsPDU *pdu, V9fsPath *path, uid_t uid,
138                                gid_t gid)
139 {
140     int err;
141     FsCred cred;
142     V9fsState *s = pdu->s;
143 
144     if (v9fs_request_cancelled(pdu)) {
145         return -EINTR;
146     }
147     cred_init(&cred);
148     cred.fc_uid = uid;
149     cred.fc_gid = gid;
150     v9fs_path_read_lock(s);
151     v9fs_co_run_in_worker(
152         {
153             err = s->ops->chown(&s->ctx, path, &cred);
154             if (err < 0) {
155                 err = -errno;
156             }
157         });
158     v9fs_path_unlock(s);
159     return err;
160 }
161 
162 int coroutine_fn v9fs_co_truncate(V9fsPDU *pdu, V9fsPath *path, off_t size)
163 {
164     int err;
165     V9fsState *s = pdu->s;
166 
167     if (v9fs_request_cancelled(pdu)) {
168         return -EINTR;
169     }
170     v9fs_path_read_lock(s);
171     v9fs_co_run_in_worker(
172         {
173             err = s->ops->truncate(&s->ctx, path, size);
174             if (err < 0) {
175                 err = -errno;
176             }
177         });
178     v9fs_path_unlock(s);
179     return err;
180 }
181 
182 int coroutine_fn v9fs_co_mknod(V9fsPDU *pdu, V9fsFidState *fidp,
183                                V9fsString *name, uid_t uid, gid_t gid,
184                                dev_t dev, mode_t mode, struct stat *stbuf)
185 {
186     int err;
187     V9fsPath path;
188     FsCred cred;
189     V9fsState *s = pdu->s;
190 
191     if (v9fs_request_cancelled(pdu)) {
192         return -EINTR;
193     }
194     cred_init(&cred);
195     cred.fc_uid  = uid;
196     cred.fc_gid  = gid;
197     cred.fc_mode = mode;
198     cred.fc_rdev = dev;
199     v9fs_path_read_lock(s);
200     v9fs_co_run_in_worker(
201         {
202             err = s->ops->mknod(&s->ctx, &fidp->path, name->data, &cred);
203             if (err < 0) {
204                 err = -errno;
205             } else {
206                 v9fs_path_init(&path);
207                 err = v9fs_name_to_path(s, &fidp->path, name->data, &path);
208                 if (!err) {
209                     err = s->ops->lstat(&s->ctx, &path, stbuf);
210                     if (err < 0) {
211                         err = -errno;
212                     }
213                 }
214                 v9fs_path_free(&path);
215             }
216         });
217     v9fs_path_unlock(s);
218     return err;
219 }
220 
221 /* Only works with path name based fid */
222 int coroutine_fn v9fs_co_remove(V9fsPDU *pdu, V9fsPath *path)
223 {
224     int err;
225     V9fsState *s = pdu->s;
226 
227     if (v9fs_request_cancelled(pdu)) {
228         return -EINTR;
229     }
230     v9fs_path_read_lock(s);
231     v9fs_co_run_in_worker(
232         {
233             err = s->ops->remove(&s->ctx, path->data);
234             if (err < 0) {
235                 err = -errno;
236             }
237         });
238     v9fs_path_unlock(s);
239     return err;
240 }
241 
242 int coroutine_fn v9fs_co_unlinkat(V9fsPDU *pdu, V9fsPath *path,
243                                   V9fsString *name, int flags)
244 {
245     int err;
246     V9fsState *s = pdu->s;
247 
248     if (v9fs_request_cancelled(pdu)) {
249         return -EINTR;
250     }
251     v9fs_path_read_lock(s);
252     v9fs_co_run_in_worker(
253         {
254             err = s->ops->unlinkat(&s->ctx, path, name->data, flags);
255             if (err < 0) {
256                 err = -errno;
257             }
258         });
259     v9fs_path_unlock(s);
260     return err;
261 }
262 
263 /* Only work with path name based fid */
264 int coroutine_fn v9fs_co_rename(V9fsPDU *pdu, V9fsPath *oldpath,
265                                 V9fsPath *newpath)
266 {
267     int err;
268     V9fsState *s = pdu->s;
269 
270     if (v9fs_request_cancelled(pdu)) {
271         return -EINTR;
272     }
273     v9fs_co_run_in_worker(
274         {
275             err = s->ops->rename(&s->ctx, oldpath->data, newpath->data);
276             if (err < 0) {
277                 err = -errno;
278             }
279         });
280     return err;
281 }
282 
283 int coroutine_fn v9fs_co_renameat(V9fsPDU *pdu, V9fsPath *olddirpath,
284                                   V9fsString *oldname, V9fsPath *newdirpath,
285                                   V9fsString *newname)
286 {
287     int err;
288     V9fsState *s = pdu->s;
289 
290     if (v9fs_request_cancelled(pdu)) {
291         return -EINTR;
292     }
293     v9fs_co_run_in_worker(
294         {
295             err = s->ops->renameat(&s->ctx, olddirpath, oldname->data,
296                                    newdirpath, newname->data);
297             if (err < 0) {
298                 err = -errno;
299             }
300         });
301     return err;
302 }
303 
304 int coroutine_fn v9fs_co_symlink(V9fsPDU *pdu, V9fsFidState *dfidp,
305                                  V9fsString *name, const char *oldpath,
306                                  gid_t gid, struct stat *stbuf)
307 {
308     int err;
309     FsCred cred;
310     V9fsPath path;
311     V9fsState *s = pdu->s;
312 
313     if (v9fs_request_cancelled(pdu)) {
314         return -EINTR;
315     }
316     cred_init(&cred);
317     cred.fc_uid = dfidp->uid;
318     cred.fc_gid = gid;
319     cred.fc_mode = 0777;
320     v9fs_path_read_lock(s);
321     v9fs_co_run_in_worker(
322         {
323             err = s->ops->symlink(&s->ctx, oldpath, &dfidp->path,
324                                   name->data, &cred);
325             if (err < 0) {
326                 err = -errno;
327             } else {
328                 v9fs_path_init(&path);
329                 err = v9fs_name_to_path(s, &dfidp->path, name->data, &path);
330                 if (!err) {
331                     err = s->ops->lstat(&s->ctx, &path, stbuf);
332                     if (err < 0) {
333                         err = -errno;
334                     }
335                 }
336                 v9fs_path_free(&path);
337             }
338         });
339     v9fs_path_unlock(s);
340     return err;
341 }
342 
343 /*
344  * For path name based fid we don't block. So we can
345  * directly call the fs driver ops.
346  */
347 int coroutine_fn v9fs_co_name_to_path(V9fsPDU *pdu, V9fsPath *dirpath,
348                                       const char *name, V9fsPath *path)
349 {
350     int err;
351     V9fsState *s = pdu->s;
352 
353     if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
354         err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
355         if (err < 0) {
356             err = -errno;
357         }
358     } else {
359         if (v9fs_request_cancelled(pdu)) {
360             return -EINTR;
361         }
362         v9fs_co_run_in_worker(
363             {
364                 err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
365                 if (err < 0) {
366                     err = -errno;
367                 }
368             });
369     }
370     return err;
371 }
372