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 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 }