hw/9pfs/cofs.c

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