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 "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 }