qemu/hw/9pfs/cofs.c
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   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
  21static 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
  53int 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
  73int 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
  94int 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
 117int 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
 138int 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
 163int 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
 183int 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 */
 223int 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
 243int 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 */
 265int 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
 284int 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
 305int 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 */
 348int 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}
 373