hw/9pfs/cofs.c

   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 "qemu/osdep.h"
  16 #include "fsdev/qemu-fsdev.h"
  17 #include "qemu/thread.h"
  18 #include "qemu/coroutine.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 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 v9fs_co_statfs(V9fsPDU *pdu, V9fsPath *path, 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 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 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 v9fs_co_chown(V9fsPDU *pdu, V9fsPath *path, uid_t uid, gid_t gid)
 138 {
 139     int err;
 140     FsCred cred;
 141     V9fsState *s = pdu->s;
 142
 143     if (v9fs_request_cancelled(pdu)) {
 144         return -EINTR;
 145     }
 146     cred_init(&cred);
 147     cred.fc_uid = uid;
 148     cred.fc_gid = gid;
 149     v9fs_path_read_lock(s);
 150     v9fs_co_run_in_worker(
 151         {
 152             err = s->ops->chown(&s->ctx, path, &cred);
 153             if (err < 0) {
 154                 err = -errno;
 155             }
 156         });
 157     v9fs_path_unlock(s);
 158     return err;
 159 }
 160
 161 int v9fs_co_truncate(V9fsPDU *pdu, V9fsPath *path, off_t size)
 162 {
 163     int err;
 164     V9fsState *s = pdu->s;
 165
 166     if (v9fs_request_cancelled(pdu)) {
 167         return -EINTR;
 168     }
 169     v9fs_path_read_lock(s);
 170     v9fs_co_run_in_worker(
 171         {
 172             err = s->ops->truncate(&s->ctx, path, size);
 173             if (err < 0) {
 174                 err = -errno;
 175             }
 176         });
 177     v9fs_path_unlock(s);
 178     return err;
 179 }
 180
 181 int v9fs_co_mknod(V9fsPDU *pdu, V9fsFidState *fidp, V9fsString *name, uid_t uid,
 182                   gid_t gid, dev_t dev, mode_t mode, struct stat *stbuf)
 183 {
 184     int err;
 185     V9fsPath path;
 186     FsCred cred;
 187     V9fsState *s = pdu->s;
 188
 189     if (v9fs_request_cancelled(pdu)) {
 190         return -EINTR;
 191     }
 192     cred_init(&cred);
 193     cred.fc_uid  = uid;
 194     cred.fc_gid  = gid;
 195     cred.fc_mode = mode;
 196     cred.fc_rdev = dev;
 197     v9fs_path_read_lock(s);
 198     v9fs_co_run_in_worker(
 199         {
 200             err = s->ops->mknod(&s->ctx, &fidp->path, name->data, &cred);
 201             if (err < 0) {
 202                 err = -errno;
 203             } else {
 204                 v9fs_path_init(&path);
 205                 err = v9fs_name_to_path(s, &fidp->path, name->data, &path);
 206                 if (!err) {
 207                     err = s->ops->lstat(&s->ctx, &path, stbuf);
 208                     if (err < 0) {
 209                         err = -errno;
 210                     }
 211                 }
 212                 v9fs_path_free(&path);
 213             }
 214         });
 215     v9fs_path_unlock(s);
 216     return err;
 217 }
 218
 219 /* Only works with path name based fid */
 220 int v9fs_co_remove(V9fsPDU *pdu, V9fsPath *path)
 221 {
 222     int err;
 223     V9fsState *s = pdu->s;
 224
 225     if (v9fs_request_cancelled(pdu)) {
 226         return -EINTR;
 227     }
 228     v9fs_path_read_lock(s);
 229     v9fs_co_run_in_worker(
 230         {
 231             err = s->ops->remove(&s->ctx, path->data);
 232             if (err < 0) {
 233                 err = -errno;
 234             }
 235         });
 236     v9fs_path_unlock(s);
 237     return err;
 238 }
 239
 240 int v9fs_co_unlinkat(V9fsPDU *pdu, V9fsPath *path, V9fsString *name, int flags)
 241 {
 242     int err;
 243     V9fsState *s = pdu->s;
 244
 245     if (v9fs_request_cancelled(pdu)) {
 246         return -EINTR;
 247     }
 248     v9fs_path_read_lock(s);
 249     v9fs_co_run_in_worker(
 250         {
 251             err = s->ops->unlinkat(&s->ctx, path, name->data, flags);
 252             if (err < 0) {
 253                 err = -errno;
 254             }
 255         });
 256     v9fs_path_unlock(s);
 257     return err;
 258 }
 259
 260 /* Only work with path name based fid */
 261 int v9fs_co_rename(V9fsPDU *pdu, V9fsPath *oldpath, V9fsPath *newpath)
 262 {
 263     int err;
 264     V9fsState *s = pdu->s;
 265
 266     if (v9fs_request_cancelled(pdu)) {
 267         return -EINTR;
 268     }
 269     v9fs_co_run_in_worker(
 270         {
 271             err = s->ops->rename(&s->ctx, oldpath->data, newpath->data);
 272             if (err < 0) {
 273                 err = -errno;
 274             }
 275         });
 276     return err;
 277 }
 278
 279 int v9fs_co_renameat(V9fsPDU *pdu, V9fsPath *olddirpath, V9fsString *oldname,
 280                      V9fsPath *newdirpath, V9fsString *newname)
 281 {
 282     int err;
 283     V9fsState *s = pdu->s;
 284
 285     if (v9fs_request_cancelled(pdu)) {
 286         return -EINTR;
 287     }
 288     v9fs_co_run_in_worker(
 289         {
 290             err = s->ops->renameat(&s->ctx, olddirpath, oldname->data,
 291                                    newdirpath, newname->data);
 292             if (err < 0) {
 293                 err = -errno;
 294             }
 295         });
 296     return err;
 297 }
 298
 299 int v9fs_co_symlink(V9fsPDU *pdu, V9fsFidState *dfidp, V9fsString *name,
 300                     const char *oldpath, gid_t gid, struct stat *stbuf)
 301 {
 302     int err;
 303     FsCred cred;
 304     V9fsPath path;
 305     V9fsState *s = pdu->s;
 306
 307     if (v9fs_request_cancelled(pdu)) {
 308         return -EINTR;
 309     }
 310     cred_init(&cred);
 311     cred.fc_uid = dfidp->uid;
 312     cred.fc_gid = gid;
 313     cred.fc_mode = 0777;
 314     v9fs_path_read_lock(s);
 315     v9fs_co_run_in_worker(
 316         {
 317             err = s->ops->symlink(&s->ctx, oldpath, &dfidp->path,
 318                                   name->data, &cred);
 319             if (err < 0) {
 320                 err = -errno;
 321             } else {
 322                 v9fs_path_init(&path);
 323                 err = v9fs_name_to_path(s, &dfidp->path, name->data, &path);
 324                 if (!err) {
 325                     err = s->ops->lstat(&s->ctx, &path, stbuf);
 326                     if (err < 0) {
 327                         err = -errno;
 328                     }
 329                 }
 330                 v9fs_path_free(&path);
 331             }
 332         });
 333     v9fs_path_unlock(s);
 334     return err;
 335 }
 336
 337 /*
 338  * For path name based fid we don't block. So we can
 339  * directly call the fs driver ops.
 340  */
 341 int v9fs_co_name_to_path(V9fsPDU *pdu, V9fsPath *dirpath,
 342                          const char *name, V9fsPath *path)
 343 {
 344     int err;
 345     V9fsState *s = pdu->s;
 346
 347     if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
 348         err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
 349         if (err < 0) {
 350             err = -errno;
 351         }
 352     } else {
 353         if (v9fs_request_cancelled(pdu)) {
 354             return -EINTR;
 355         }
 356         v9fs_co_run_in_worker(
 357             {
 358                 err = s->ops->name_to_path(&s->ctx, dirpath, name, path);
 359                 if (err < 0) {
 360                     err = -errno;
 361                 }
 362             });
 363     }
 364     return err;
 365 }