1 /* 2 * Virtio 9p synthetic file system support 3 * 4 * Copyright IBM, Corp. 2011 5 * 6 * Authors: 7 * Malahal Naineni <malahal@us.ibm.com> 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 "hw/virtio/virtio.h" 17 #include "9p.h" 18 #include "9p-xattr.h" 19 #include "fsdev/qemu-fsdev.h" 20 #include "9p-synth.h" 21 #include "qemu/rcu.h" 22 #include "qemu/rcu_queue.h" 23 24 /* Root node for synth file system */ 25 static V9fsSynthNode v9fs_synth_root = { 26 .name = "/", 27 .actual_attr = { 28 .mode = 0555 | S_IFDIR, 29 .nlink = 1, 30 }, 31 .attr = &v9fs_synth_root.actual_attr, 32 }; 33 34 static QemuMutex v9fs_synth_mutex; 35 static int v9fs_synth_node_count; 36 /* set to 1 when the synth fs is ready */ 37 static int v9fs_synth_fs; 38 39 static V9fsSynthNode *v9fs_add_dir_node(V9fsSynthNode *parent, int mode, 40 const char *name, 41 V9fsSynthNodeAttr *attr, int inode) 42 { 43 V9fsSynthNode *node; 44 45 /* Add directory type and remove write bits */ 46 mode = ((mode & 0777) | S_IFDIR) & ~(S_IWUSR | S_IWGRP | S_IWOTH); 47 node = g_malloc0(sizeof(V9fsSynthNode)); 48 if (attr) { 49 /* We are adding .. or . entries */ 50 node->attr = attr; 51 node->attr->nlink++; 52 } else { 53 node->attr = &node->actual_attr; 54 node->attr->inode = inode; 55 node->attr->nlink = 1; 56 /* We don't allow write to directories */ 57 node->attr->mode = mode; 58 node->attr->write = NULL; 59 node->attr->read = NULL; 60 } 61 node->private = node; 62 pstrcpy(node->name, sizeof(node->name), name); 63 QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling); 64 return node; 65 } 66 67 int qemu_v9fs_synth_mkdir(V9fsSynthNode *parent, int mode, 68 const char *name, V9fsSynthNode **result) 69 { 70 int ret; 71 V9fsSynthNode *node, *tmp; 72 73 if (!v9fs_synth_fs) { 74 return EAGAIN; 75 } 76 if (!name || (strlen(name) >= NAME_MAX)) { 77 return EINVAL; 78 } 79 if (!parent) { 80 parent = &v9fs_synth_root; 81 } 82 qemu_mutex_lock(&v9fs_synth_mutex); 83 QLIST_FOREACH(tmp, &parent->child, sibling) { 84 if (!strcmp(tmp->name, name)) { 85 ret = EEXIST; 86 goto err_out; 87 } 88 } 89 /* Add the name */ 90 node = v9fs_add_dir_node(parent, mode, name, NULL, v9fs_synth_node_count++); 91 v9fs_add_dir_node(node, parent->attr->mode, "..", 92 parent->attr, parent->attr->inode); 93 v9fs_add_dir_node(node, node->attr->mode, ".", 94 node->attr, node->attr->inode); 95 *result = node; 96 ret = 0; 97 err_out: 98 qemu_mutex_unlock(&v9fs_synth_mutex); 99 return ret; 100 } 101 102 int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode, 103 const char *name, v9fs_synth_read read, 104 v9fs_synth_write write, void *arg) 105 { 106 int ret; 107 V9fsSynthNode *node, *tmp; 108 109 if (!v9fs_synth_fs) { 110 return EAGAIN; 111 } 112 if (!name || (strlen(name) >= NAME_MAX)) { 113 return EINVAL; 114 } 115 if (!parent) { 116 parent = &v9fs_synth_root; 117 } 118 119 qemu_mutex_lock(&v9fs_synth_mutex); 120 QLIST_FOREACH(tmp, &parent->child, sibling) { 121 if (!strcmp(tmp->name, name)) { 122 ret = EEXIST; 123 goto err_out; 124 } 125 } 126 /* Add file type and remove write bits */ 127 mode = ((mode & 0777) | S_IFREG); 128 node = g_malloc0(sizeof(V9fsSynthNode)); 129 node->attr = &node->actual_attr; 130 node->attr->inode = v9fs_synth_node_count++; 131 node->attr->nlink = 1; 132 node->attr->read = read; 133 node->attr->write = write; 134 node->attr->mode = mode; 135 node->private = arg; 136 pstrcpy(node->name, sizeof(node->name), name); 137 QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling); 138 ret = 0; 139 err_out: 140 qemu_mutex_unlock(&v9fs_synth_mutex); 141 return ret; 142 } 143 144 static void v9fs_synth_fill_statbuf(V9fsSynthNode *node, struct stat *stbuf) 145 { 146 stbuf->st_dev = 0; 147 stbuf->st_ino = node->attr->inode; 148 stbuf->st_mode = node->attr->mode; 149 stbuf->st_nlink = node->attr->nlink; 150 stbuf->st_uid = 0; 151 stbuf->st_gid = 0; 152 stbuf->st_rdev = 0; 153 stbuf->st_size = 0; 154 stbuf->st_blksize = 0; 155 stbuf->st_blocks = 0; 156 stbuf->st_atime = 0; 157 stbuf->st_mtime = 0; 158 stbuf->st_ctime = 0; 159 } 160 161 static int v9fs_synth_lstat(FsContext *fs_ctx, 162 V9fsPath *fs_path, struct stat *stbuf) 163 { 164 V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data; 165 166 v9fs_synth_fill_statbuf(node, stbuf); 167 return 0; 168 } 169 170 static int v9fs_synth_fstat(FsContext *fs_ctx, int fid_type, 171 V9fsFidOpenState *fs, struct stat *stbuf) 172 { 173 V9fsSynthOpenState *synth_open = fs->private; 174 v9fs_synth_fill_statbuf(synth_open->node, stbuf); 175 return 0; 176 } 177 178 static int v9fs_synth_opendir(FsContext *ctx, 179 V9fsPath *fs_path, V9fsFidOpenState *fs) 180 { 181 V9fsSynthOpenState *synth_open; 182 V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data; 183 184 synth_open = g_malloc(sizeof(*synth_open)); 185 synth_open->node = node; 186 node->open_count++; 187 fs->private = synth_open; 188 return 0; 189 } 190 191 static int v9fs_synth_closedir(FsContext *ctx, V9fsFidOpenState *fs) 192 { 193 V9fsSynthOpenState *synth_open = fs->private; 194 V9fsSynthNode *node = synth_open->node; 195 196 node->open_count--; 197 g_free(synth_open); 198 fs->private = NULL; 199 return 0; 200 } 201 202 static off_t v9fs_synth_telldir(FsContext *ctx, V9fsFidOpenState *fs) 203 { 204 V9fsSynthOpenState *synth_open = fs->private; 205 return synth_open->offset; 206 } 207 208 static void v9fs_synth_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off) 209 { 210 V9fsSynthOpenState *synth_open = fs->private; 211 synth_open->offset = off; 212 } 213 214 static void v9fs_synth_rewinddir(FsContext *ctx, V9fsFidOpenState *fs) 215 { 216 v9fs_synth_seekdir(ctx, fs, 0); 217 } 218 219 static void v9fs_synth_direntry(V9fsSynthNode *node, 220 struct dirent *entry, off_t off) 221 { 222 strcpy(entry->d_name, node->name); 223 entry->d_ino = node->attr->inode; 224 entry->d_off = off + 1; 225 } 226 227 static int v9fs_synth_get_dentry(V9fsSynthNode *dir, struct dirent *entry, 228 struct dirent **result, off_t off) 229 { 230 int i = 0; 231 V9fsSynthNode *node; 232 233 rcu_read_lock(); 234 QLIST_FOREACH(node, &dir->child, sibling) { 235 /* This is the off child of the directory */ 236 if (i == off) { 237 break; 238 } 239 i++; 240 } 241 rcu_read_unlock(); 242 if (!node) { 243 /* end of directory */ 244 *result = NULL; 245 return 0; 246 } 247 v9fs_synth_direntry(node, entry, off); 248 *result = entry; 249 return 0; 250 } 251 252 static int v9fs_synth_readdir_r(FsContext *ctx, V9fsFidOpenState *fs, 253 struct dirent *entry, struct dirent **result) 254 { 255 int ret; 256 V9fsSynthOpenState *synth_open = fs->private; 257 V9fsSynthNode *node = synth_open->node; 258 ret = v9fs_synth_get_dentry(node, entry, result, synth_open->offset); 259 if (!ret && *result != NULL) { 260 synth_open->offset++; 261 } 262 return ret; 263 } 264 265 static int v9fs_synth_open(FsContext *ctx, V9fsPath *fs_path, 266 int flags, V9fsFidOpenState *fs) 267 { 268 V9fsSynthOpenState *synth_open; 269 V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data; 270 271 synth_open = g_malloc(sizeof(*synth_open)); 272 synth_open->node = node; 273 node->open_count++; 274 fs->private = synth_open; 275 return 0; 276 } 277 278 static int v9fs_synth_open2(FsContext *fs_ctx, V9fsPath *dir_path, 279 const char *name, int flags, 280 FsCred *credp, V9fsFidOpenState *fs) 281 { 282 errno = ENOSYS; 283 return -1; 284 } 285 286 static int v9fs_synth_close(FsContext *ctx, V9fsFidOpenState *fs) 287 { 288 V9fsSynthOpenState *synth_open = fs->private; 289 V9fsSynthNode *node = synth_open->node; 290 291 node->open_count--; 292 g_free(synth_open); 293 fs->private = NULL; 294 return 0; 295 } 296 297 static ssize_t v9fs_synth_pwritev(FsContext *ctx, V9fsFidOpenState *fs, 298 const struct iovec *iov, 299 int iovcnt, off_t offset) 300 { 301 int i, count = 0, wcount; 302 V9fsSynthOpenState *synth_open = fs->private; 303 V9fsSynthNode *node = synth_open->node; 304 if (!node->attr->write) { 305 errno = EPERM; 306 return -1; 307 } 308 for (i = 0; i < iovcnt; i++) { 309 wcount = node->attr->write(iov[i].iov_base, iov[i].iov_len, 310 offset, node->private); 311 offset += wcount; 312 count += wcount; 313 /* If we wrote less than requested. we are done */ 314 if (wcount < iov[i].iov_len) { 315 break; 316 } 317 } 318 return count; 319 } 320 321 static ssize_t v9fs_synth_preadv(FsContext *ctx, V9fsFidOpenState *fs, 322 const struct iovec *iov, 323 int iovcnt, off_t offset) 324 { 325 int i, count = 0, rcount; 326 V9fsSynthOpenState *synth_open = fs->private; 327 V9fsSynthNode *node = synth_open->node; 328 if (!node->attr->read) { 329 errno = EPERM; 330 return -1; 331 } 332 for (i = 0; i < iovcnt; i++) { 333 rcount = node->attr->read(iov[i].iov_base, iov[i].iov_len, 334 offset, node->private); 335 offset += rcount; 336 count += rcount; 337 /* If we read less than requested. we are done */ 338 if (rcount < iov[i].iov_len) { 339 break; 340 } 341 } 342 return count; 343 } 344 345 static int v9fs_synth_truncate(FsContext *ctx, V9fsPath *path, off_t offset) 346 { 347 errno = ENOSYS; 348 return -1; 349 } 350 351 static int v9fs_synth_chmod(FsContext *fs_ctx, V9fsPath *path, FsCred *credp) 352 { 353 errno = EPERM; 354 return -1; 355 } 356 357 static int v9fs_synth_mknod(FsContext *fs_ctx, V9fsPath *path, 358 const char *buf, FsCred *credp) 359 { 360 errno = EPERM; 361 return -1; 362 } 363 364 static int v9fs_synth_mkdir(FsContext *fs_ctx, V9fsPath *path, 365 const char *buf, FsCred *credp) 366 { 367 errno = EPERM; 368 return -1; 369 } 370 371 static ssize_t v9fs_synth_readlink(FsContext *fs_ctx, V9fsPath *path, 372 char *buf, size_t bufsz) 373 { 374 errno = ENOSYS; 375 return -1; 376 } 377 378 static int v9fs_synth_symlink(FsContext *fs_ctx, const char *oldpath, 379 V9fsPath *newpath, const char *buf, FsCred *credp) 380 { 381 errno = EPERM; 382 return -1; 383 } 384 385 static int v9fs_synth_link(FsContext *fs_ctx, V9fsPath *oldpath, 386 V9fsPath *newpath, const char *buf) 387 { 388 errno = EPERM; 389 return -1; 390 } 391 392 static int v9fs_synth_rename(FsContext *ctx, const char *oldpath, 393 const char *newpath) 394 { 395 errno = EPERM; 396 return -1; 397 } 398 399 static int v9fs_synth_chown(FsContext *fs_ctx, V9fsPath *path, FsCred *credp) 400 { 401 errno = EPERM; 402 return -1; 403 } 404 405 static int v9fs_synth_utimensat(FsContext *fs_ctx, V9fsPath *path, 406 const struct timespec *buf) 407 { 408 errno = EPERM; 409 return 0; 410 } 411 412 static int v9fs_synth_remove(FsContext *ctx, const char *path) 413 { 414 errno = EPERM; 415 return -1; 416 } 417 418 static int v9fs_synth_fsync(FsContext *ctx, int fid_type, 419 V9fsFidOpenState *fs, int datasync) 420 { 421 errno = ENOSYS; 422 return 0; 423 } 424 425 static int v9fs_synth_statfs(FsContext *s, V9fsPath *fs_path, 426 struct statfs *stbuf) 427 { 428 stbuf->f_type = 0xABCD; 429 stbuf->f_bsize = 512; 430 stbuf->f_blocks = 0; 431 stbuf->f_files = v9fs_synth_node_count; 432 stbuf->f_namelen = NAME_MAX; 433 return 0; 434 } 435 436 static ssize_t v9fs_synth_lgetxattr(FsContext *ctx, V9fsPath *path, 437 const char *name, void *value, size_t size) 438 { 439 errno = ENOTSUP; 440 return -1; 441 } 442 443 static ssize_t v9fs_synth_llistxattr(FsContext *ctx, V9fsPath *path, 444 void *value, size_t size) 445 { 446 errno = ENOTSUP; 447 return -1; 448 } 449 450 static int v9fs_synth_lsetxattr(FsContext *ctx, V9fsPath *path, 451 const char *name, void *value, 452 size_t size, int flags) 453 { 454 errno = ENOTSUP; 455 return -1; 456 } 457 458 static int v9fs_synth_lremovexattr(FsContext *ctx, 459 V9fsPath *path, const char *name) 460 { 461 errno = ENOTSUP; 462 return -1; 463 } 464 465 static int v9fs_synth_name_to_path(FsContext *ctx, V9fsPath *dir_path, 466 const char *name, V9fsPath *target) 467 { 468 V9fsSynthNode *node; 469 V9fsSynthNode *dir_node; 470 471 /* "." and ".." are not allowed */ 472 if (!strcmp(name, ".") || !strcmp(name, "..")) { 473 errno = EINVAL; 474 return -1; 475 476 } 477 if (!dir_path) { 478 dir_node = &v9fs_synth_root; 479 } else { 480 dir_node = *(V9fsSynthNode **)dir_path->data; 481 } 482 if (!strcmp(name, "/")) { 483 node = dir_node; 484 goto out; 485 } 486 /* search for the name in the childern */ 487 rcu_read_lock(); 488 QLIST_FOREACH(node, &dir_node->child, sibling) { 489 if (!strcmp(node->name, name)) { 490 break; 491 } 492 } 493 rcu_read_unlock(); 494 495 if (!node) { 496 errno = ENOENT; 497 return -1; 498 } 499 out: 500 /* Copy the node pointer to fid */ 501 target->data = g_malloc(sizeof(void *)); 502 memcpy(target->data, &node, sizeof(void *)); 503 target->size = sizeof(void *); 504 return 0; 505 } 506 507 static int v9fs_synth_renameat(FsContext *ctx, V9fsPath *olddir, 508 const char *old_name, V9fsPath *newdir, 509 const char *new_name) 510 { 511 errno = EPERM; 512 return -1; 513 } 514 515 static int v9fs_synth_unlinkat(FsContext *ctx, V9fsPath *dir, 516 const char *name, int flags) 517 { 518 errno = EPERM; 519 return -1; 520 } 521 522 static int v9fs_synth_init(FsContext *ctx) 523 { 524 QLIST_INIT(&v9fs_synth_root.child); 525 qemu_mutex_init(&v9fs_synth_mutex); 526 527 /* Add "." and ".." entries for root */ 528 v9fs_add_dir_node(&v9fs_synth_root, v9fs_synth_root.attr->mode, 529 "..", v9fs_synth_root.attr, v9fs_synth_root.attr->inode); 530 v9fs_add_dir_node(&v9fs_synth_root, v9fs_synth_root.attr->mode, 531 ".", v9fs_synth_root.attr, v9fs_synth_root.attr->inode); 532 533 /* Mark the subsystem is ready for use */ 534 v9fs_synth_fs = 1; 535 return 0; 536 } 537 538 FileOperations synth_ops = { 539 .init = v9fs_synth_init, 540 .lstat = v9fs_synth_lstat, 541 .readlink = v9fs_synth_readlink, 542 .close = v9fs_synth_close, 543 .closedir = v9fs_synth_closedir, 544 .open = v9fs_synth_open, 545 .opendir = v9fs_synth_opendir, 546 .rewinddir = v9fs_synth_rewinddir, 547 .telldir = v9fs_synth_telldir, 548 .readdir_r = v9fs_synth_readdir_r, 549 .seekdir = v9fs_synth_seekdir, 550 .preadv = v9fs_synth_preadv, 551 .pwritev = v9fs_synth_pwritev, 552 .chmod = v9fs_synth_chmod, 553 .mknod = v9fs_synth_mknod, 554 .mkdir = v9fs_synth_mkdir, 555 .fstat = v9fs_synth_fstat, 556 .open2 = v9fs_synth_open2, 557 .symlink = v9fs_synth_symlink, 558 .link = v9fs_synth_link, 559 .truncate = v9fs_synth_truncate, 560 .rename = v9fs_synth_rename, 561 .chown = v9fs_synth_chown, 562 .utimensat = v9fs_synth_utimensat, 563 .remove = v9fs_synth_remove, 564 .fsync = v9fs_synth_fsync, 565 .statfs = v9fs_synth_statfs, 566 .lgetxattr = v9fs_synth_lgetxattr, 567 .llistxattr = v9fs_synth_llistxattr, 568 .lsetxattr = v9fs_synth_lsetxattr, 569 .lremovexattr = v9fs_synth_lremovexattr, 570 .name_to_path = v9fs_synth_name_to_path, 571 .renameat = v9fs_synth_renameat, 572 .unlinkat = v9fs_synth_unlinkat, 573 }; 574