xref: /openbmc/qemu/hw/9pfs/cofs.c (revision 23792478) 
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 
__readlink(V9fsState * s,V9fsPath * path,V9fsString * buf)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 
v9fs_co_readlink(V9fsPDU * pdu,V9fsPath * path,V9fsString * buf)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 
v9fs_co_statfs(V9fsPDU * pdu,V9fsPath * path,struct statfs * stbuf)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 
v9fs_co_chmod(V9fsPDU * pdu,V9fsPath * path,mode_t mode)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 
v9fs_co_utimensat(V9fsPDU * pdu,V9fsPath * path,struct timespec times[2])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 
v9fs_co_chown(V9fsPDU * pdu,V9fsPath * path,uid_t uid,gid_t gid)142 int coroutine_fn v9fs_co_chown(V9fsPDU *pdu, V9fsPath *path, uid_t uid,
143                                gid_t gid)
144 {
145     int err;
146     FsCred cred;
147     V9fsState *s = pdu->s;
148 
149     if (v9fs_request_cancelled(pdu)) {
150         return -EINTR;
151     }
152     cred_init(&cred);
153     cred.fc_uid = uid;
154     cred.fc_gid = gid;
155     v9fs_path_read_lock(s);
156     v9fs_co_run_in_worker(
157         {
158             err = s->ops->chown(&s->ctx, path, &cred);
159             if (err < 0) {
160                 err = -errno;
161             }
162         });
163     v9fs_path_unlock(s);
164     return err;
165 }
166 
v9fs_co_truncate(V9fsPDU * pdu,V9fsPath * path,off_t size)167 int coroutine_fn v9fs_co_truncate(V9fsPDU *pdu, V9fsPath *path, off_t size)
168 {
169     int err;
170     V9fsState *s = pdu->s;
171 
172     if (v9fs_request_cancelled(pdu)) {
173         return -EINTR;
174     }
175     v9fs_path_read_lock(s);
176     v9fs_co_run_in_worker(
177         {
178             err = s->ops->truncate(&s->ctx, path, size);
179             if (err < 0) {
180                 err = -errno;
181             }
182         });
183     v9fs_path_unlock(s);
184     return err;
185 }
186 
v9fs_co_mknod(V9fsPDU * pdu,V9fsFidState * fidp,V9fsString * name,uid_t uid,gid_t gid,dev_t dev,mode_t mode,struct stat * stbuf)187 int coroutine_fn v9fs_co_mknod(V9fsPDU *pdu, V9fsFidState *fidp,
188                                V9fsString *name, uid_t uid, gid_t gid,
189                                dev_t dev, mode_t mode, struct stat *stbuf)
190 {
191     int err;
192     V9fsPath path;
193     FsCred cred;
194     V9fsState *s = pdu->s;
195 
196     if (v9fs_request_cancelled(pdu)) {
197         return -EINTR;
198     }
199     cred_init(&cred);
200     cred.fc_uid  = uid;
201     cred.fc_gid  = gid;
202     cred.fc_mode = mode;
203     cred.fc_rdev = dev;
204     v9fs_path_read_lock(s);
205     v9fs_co_run_in_worker(
206         {
207             err = s->ops->mknod(&s->ctx, &fidp->path, name->data, &cred);
208             if (err < 0) {
209                 err = -errno;
210             } else {
211                 v9fs_path_init(&path);
212                 err = v9fs_name_to_path(s, &fidp->path, name->data, &path);
213                 if (!err) {
214                     err = s->ops->lstat(&s->ctx, &path, stbuf);
215                     if (err < 0) {
216                         err = -errno;
217                     }
218                 }
219                 v9fs_path_free(&path);
220             }
221         });
222     v9fs_path_unlock(s);
223     return err;
224 }
225 
226 /* Only works with path name based fid */
v9fs_co_remove(V9fsPDU * pdu,V9fsPath * path)227 int coroutine_fn v9fs_co_remove(V9fsPDU *pdu, V9fsPath *path)
228 {
229     int err;
230     V9fsState *s = pdu->s;
231 
232     if (v9fs_request_cancelled(pdu)) {
233         return -EINTR;
234     }
235     v9fs_path_read_lock(s);
236     v9fs_co_run_in_worker(
237         {
238             err = s->ops->remove(&s->ctx, path->data);
239             if (err < 0) {
240                 err = -errno;
241             }
242         });
243     v9fs_path_unlock(s);
244     return err;
245 }
246 
v9fs_co_unlinkat(V9fsPDU * pdu,V9fsPath * path,V9fsString * name,int flags)247 int coroutine_fn v9fs_co_unlinkat(V9fsPDU *pdu, V9fsPath *path,
248                                   V9fsString *name, int flags)
249 {
250     int err;
251     V9fsState *s = pdu->s;
252 
253     if (v9fs_request_cancelled(pdu)) {
254         return -EINTR;
255     }
256     v9fs_path_read_lock(s);
257     v9fs_co_run_in_worker(
258         {
259             err = s->ops->unlinkat(&s->ctx, path, name->data, flags);
260             if (err < 0) {
261                 err = -errno;
262             }
263         });
264     v9fs_path_unlock(s);
265     return err;
266 }
267 
268 /* Only work with path name based fid */
v9fs_co_rename(V9fsPDU * pdu,V9fsPath * oldpath,V9fsPath * newpath)269 int coroutine_fn v9fs_co_rename(V9fsPDU *pdu, V9fsPath *oldpath,
270                                 V9fsPath *newpath)
271 {
272     int err;
273     V9fsState *s = pdu->s;
274 
275     if (v9fs_request_cancelled(pdu)) {
276         return -EINTR;
277     }
278     v9fs_co_run_in_worker(
279         {
280             err = s->ops->rename(&s->ctx, oldpath->data, newpath->data);
281             if (err < 0) {
282                 err = -errno;
283             }
284         });
285     return err;
286 }
287 
v9fs_co_renameat(V9fsPDU * pdu,V9fsPath * olddirpath,V9fsString * oldname,V9fsPath * newdirpath,V9fsString * newname)288 int coroutine_fn v9fs_co_renameat(V9fsPDU *pdu, V9fsPath *olddirpath,
289                                   V9fsString *oldname, V9fsPath *newdirpath,
290                                   V9fsString *newname)
291 {
292     int err;
293     V9fsState *s = pdu->s;
294 
295     if (v9fs_request_cancelled(pdu)) {
296         return -EINTR;
297     }
298     v9fs_co_run_in_worker(
299         {
300             err = s->ops->renameat(&s->ctx, olddirpath, oldname->data,
301                                    newdirpath, newname->data);
302             if (err < 0) {
303                 err = -errno;
304             }
305         });
306     return err;
307 }
308 
v9fs_co_symlink(V9fsPDU * pdu,V9fsFidState * dfidp,V9fsString * name,const char * oldpath,gid_t gid,struct stat * stbuf)309 int coroutine_fn v9fs_co_symlink(V9fsPDU *pdu, V9fsFidState *dfidp,
310                                  V9fsString *name, const char *oldpath,
311                                  gid_t gid, struct stat *stbuf)
312 {
313     int err;
314     FsCred cred;
315     V9fsPath path;
316     V9fsState *s = pdu->s;
317 
318     if (v9fs_request_cancelled(pdu)) {
319         return -EINTR;
320     }
321     cred_init(&cred);
322     cred.fc_uid = dfidp->uid;
323     cred.fc_gid = gid;
324     cred.fc_mode = 0777;
325     v9fs_path_read_lock(s);
326     v9fs_co_run_in_worker(
327         {
328             err = s->ops->symlink(&s->ctx, oldpath, &dfidp->path,
329                                   name->data, &cred);
330             if (err < 0) {
331                 err = -errno;
332             } else {
333                 v9fs_path_init(&path);
334                 err = v9fs_name_to_path(s, &dfidp->path, name->data, &path);
335                 if (!err) {
336                     err = s->ops->lstat(&s->ctx, &path, stbuf);
337                     if (err < 0) {
338                         err = -errno;
339                     }
340                 }
341                 v9fs_path_free(&path);
342             }
343         });
344     v9fs_path_unlock(s);
345     return err;
346 }
347 
348 /*
349  * For path name based fid we don't block. So we can
350  * directly call the fs driver ops.
351  */
v9fs_co_name_to_path(V9fsPDU * pdu,V9fsPath * dirpath,const char * name,V9fsPath * path)352 int coroutine_fn v9fs_co_name_to_path(V9fsPDU *pdu, V9fsPath *dirpath,
353                                       const char *name, V9fsPath *path)
354 {
355     int err;
356     V9fsState *s = pdu->s;
357 
358     if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
359         err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
360         if (err < 0) {
361             err = -errno;
362         }
363     } else {
364         if (v9fs_request_cancelled(pdu)) {
365             return -EINTR;
366         }
367         v9fs_co_run_in_worker(
368             {
369                 err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
370                 if (err < 0) {
371                     err = -errno;
372                 }
373             });
374     }
375     return err;
376 }
377