1 /* 2 * 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 "9p.h" 17 #include "fsdev/qemu-fsdev.h" 18 #include "9p-synth.h" 19 #include "qemu/rcu.h" 20 #include "qemu/rcu_queue.h" 21 #include "qemu/cutils.h" 22 23 /* Root node for synth file system */ 24 static V9fsSynthNode synth_root = { 25 .name = "/", 26 .actual_attr = { 27 .mode = 0555 | S_IFDIR, 28 .nlink = 1, 29 }, 30 .attr = &synth_root.actual_attr, 31 }; 32 33 static QemuMutex synth_mutex; 34 static int synth_node_count; 35 /* set to 1 when the synth fs is ready */ 36 static int synth_fs; 37 38 static V9fsSynthNode *v9fs_add_dir_node(V9fsSynthNode *parent, int mode, 39 const char *name, 40 V9fsSynthNodeAttr *attr, int inode) 41 { 42 V9fsSynthNode *node; 43 44 /* Add directory type and remove write bits */ 45 mode = ((mode & 0777) | S_IFDIR) & ~(S_IWUSR | S_IWGRP | S_IWOTH); 46 node = g_malloc0(sizeof(V9fsSynthNode)); 47 if (attr) { 48 /* We are adding .. or . entries */ 49 node->attr = attr; 50 node->attr->nlink++; 51 } else { 52 node->attr = &node->actual_attr; 53 node->attr->inode = inode; 54 node->attr->nlink = 1; 55 /* We don't allow write to directories */ 56 node->attr->mode = mode; 57 node->attr->write = NULL; 58 node->attr->read = NULL; 59 } 60 node->private = node; 61 pstrcpy(node->name, sizeof(node->name), name); 62 QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling); 63 return node; 64 } 65 66 int qemu_v9fs_synth_mkdir(V9fsSynthNode *parent, int mode, 67 const char *name, V9fsSynthNode **result) 68 { 69 int ret; 70 V9fsSynthNode *node, *tmp; 71 72 if (!synth_fs) { 73 return EAGAIN; 74 } 75 if (!name || (strlen(name) >= NAME_MAX)) { 76 return EINVAL; 77 } 78 if (!parent) { 79 parent = &synth_root; 80 } 81 qemu_mutex_lock(&synth_mutex); 82 QLIST_FOREACH(tmp, &parent->child, sibling) { 83 if (!strcmp(tmp->name, name)) { 84 ret = EEXIST; 85 goto err_out; 86 } 87 } 88 /* Add the name */ 89 node = v9fs_add_dir_node(parent, mode, name, NULL, synth_node_count++); 90 v9fs_add_dir_node(node, parent->attr->mode, "..", 91 parent->attr, parent->attr->inode); 92 v9fs_add_dir_node(node, node->attr->mode, ".", 93 node->attr, node->attr->inode); 94 *result = node; 95 ret = 0; 96 err_out: 97 qemu_mutex_unlock(&synth_mutex); 98 return ret; 99 } 100 101 int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode, 102 const char *name, v9fs_synth_read read, 103 v9fs_synth_write write, void *arg) 104 { 105 int ret; 106 V9fsSynthNode *node, *tmp; 107 108 if (!synth_fs) { 109 return EAGAIN; 110 } 111 if (!name || (strlen(name) >= NAME_MAX)) { 112 return EINVAL; 113 } 114 if (!parent) { 115 parent = &synth_root; 116 } 117 118 qemu_mutex_lock(&synth_mutex); 119 QLIST_FOREACH(tmp, &parent->child, sibling) { 120 if (!strcmp(tmp->name, name)) { 121 ret = EEXIST; 122 goto err_out; 123 } 124 } 125 /* Add file type and remove write bits */ 126 mode = ((mode & 0777) | S_IFREG); 127 node = g_malloc0(sizeof(V9fsSynthNode)); 128 node->attr = &node->actual_attr; 129 node->attr->inode = synth_node_count++; 130 node->attr->nlink = 1; 131 node->attr->read = read; 132 node->attr->write = write; 133 node->attr->mode = mode; 134 node->private = arg; 135 pstrcpy(node->name, sizeof(node->name), name); 136 QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling); 137 ret = 0; 138 err_out: 139 qemu_mutex_unlock(&synth_mutex); 140 return ret; 141 } 142 143 static void synth_fill_statbuf(V9fsSynthNode *node, struct stat *stbuf) 144 { 145 stbuf->st_dev = 0; 146 stbuf->st_ino = node->attr->inode; 147 stbuf->st_mode = node->attr->mode; 148 stbuf->st_nlink = node->attr->nlink; 149 stbuf->st_uid = 0; 150 stbuf->st_gid = 0; 151 stbuf->st_rdev = 0; 152 stbuf->st_size = 0; 153 stbuf->st_blksize = 0; 154 stbuf->st_blocks = 0; 155 stbuf->st_atime = 0; 156 stbuf->st_mtime = 0; 157 stbuf->st_ctime = 0; 158 } 159 160 static int synth_lstat(FsContext *fs_ctx, 161 V9fsPath *fs_path, struct stat *stbuf) 162 { 163 V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data; 164 165 synth_fill_statbuf(node, stbuf); 166 return 0; 167 } 168 169 static int synth_fstat(FsContext *fs_ctx, int fid_type, 170 V9fsFidOpenState *fs, struct stat *stbuf) 171 { 172 V9fsSynthOpenState *synth_open = fs->private; 173 synth_fill_statbuf(synth_open->node, stbuf); 174 return 0; 175 } 176 177 static int synth_opendir(FsContext *ctx, 178 V9fsPath *fs_path, V9fsFidOpenState *fs) 179 { 180 V9fsSynthOpenState *synth_open; 181 V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data; 182 183 synth_open = g_malloc(sizeof(*synth_open)); 184 synth_open->node = node; 185 node->open_count++; 186 fs->private = synth_open; 187 return 0; 188 } 189 190 static int synth_closedir(FsContext *ctx, V9fsFidOpenState *fs) 191 { 192 V9fsSynthOpenState *synth_open = fs->private; 193 V9fsSynthNode *node = synth_open->node; 194 195 node->open_count--; 196 g_free(synth_open); 197 fs->private = NULL; 198 return 0; 199 } 200 201 static off_t synth_telldir(FsContext *ctx, V9fsFidOpenState *fs) 202 { 203 V9fsSynthOpenState *synth_open = fs->private; 204 return synth_open->offset; 205 } 206 207 static void synth_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off) 208 { 209 V9fsSynthOpenState *synth_open = fs->private; 210 synth_open->offset = off; 211 } 212 213 static void synth_rewinddir(FsContext *ctx, V9fsFidOpenState *fs) 214 { 215 synth_seekdir(ctx, fs, 0); 216 } 217 218 static void synth_direntry(V9fsSynthNode *node, 219 struct dirent *entry, off_t off) 220 { 221 strcpy(entry->d_name, node->name); 222 entry->d_ino = node->attr->inode; 223 entry->d_off = off + 1; 224 } 225 226 static struct dirent *synth_get_dentry(V9fsSynthNode *dir, 227 struct dirent *entry, off_t off) 228 { 229 int i = 0; 230 V9fsSynthNode *node; 231 232 rcu_read_lock(); 233 QLIST_FOREACH(node, &dir->child, sibling) { 234 /* This is the off child of the directory */ 235 if (i == off) { 236 break; 237 } 238 i++; 239 } 240 rcu_read_unlock(); 241 if (!node) { 242 /* end of directory */ 243 return NULL; 244 } 245 synth_direntry(node, entry, off); 246 return entry; 247 } 248 249 static struct dirent *synth_readdir(FsContext *ctx, V9fsFidOpenState *fs) 250 { 251 struct dirent *entry; 252 V9fsSynthOpenState *synth_open = fs->private; 253 V9fsSynthNode *node = synth_open->node; 254 entry = synth_get_dentry(node, &synth_open->dent, synth_open->offset); 255 if (entry) { 256 synth_open->offset++; 257 } 258 return entry; 259 } 260 261 static int synth_open(FsContext *ctx, V9fsPath *fs_path, 262 int flags, V9fsFidOpenState *fs) 263 { 264 V9fsSynthOpenState *synth_open; 265 V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data; 266 267 synth_open = g_malloc(sizeof(*synth_open)); 268 synth_open->node = node; 269 node->open_count++; 270 fs->private = synth_open; 271 return 0; 272 } 273 274 static int synth_open2(FsContext *fs_ctx, V9fsPath *dir_path, 275 const char *name, int flags, 276 FsCred *credp, V9fsFidOpenState *fs) 277 { 278 errno = ENOSYS; 279 return -1; 280 } 281 282 static int synth_close(FsContext *ctx, V9fsFidOpenState *fs) 283 { 284 V9fsSynthOpenState *synth_open = fs->private; 285 V9fsSynthNode *node = synth_open->node; 286 287 node->open_count--; 288 g_free(synth_open); 289 fs->private = NULL; 290 return 0; 291 } 292 293 static ssize_t synth_pwritev(FsContext *ctx, V9fsFidOpenState *fs, 294 const struct iovec *iov, 295 int iovcnt, off_t offset) 296 { 297 int i, count = 0, wcount; 298 V9fsSynthOpenState *synth_open = fs->private; 299 V9fsSynthNode *node = synth_open->node; 300 if (!node->attr->write) { 301 errno = EPERM; 302 return -1; 303 } 304 for (i = 0; i < iovcnt; i++) { 305 wcount = node->attr->write(iov[i].iov_base, iov[i].iov_len, 306 offset, node->private); 307 offset += wcount; 308 count += wcount; 309 /* If we wrote less than requested. we are done */ 310 if (wcount < iov[i].iov_len) { 311 break; 312 } 313 } 314 return count; 315 } 316 317 static ssize_t synth_preadv(FsContext *ctx, V9fsFidOpenState *fs, 318 const struct iovec *iov, 319 int iovcnt, off_t offset) 320 { 321 int i, count = 0, rcount; 322 V9fsSynthOpenState *synth_open = fs->private; 323 V9fsSynthNode *node = synth_open->node; 324 if (!node->attr->read) { 325 errno = EPERM; 326 return -1; 327 } 328 for (i = 0; i < iovcnt; i++) { 329 rcount = node->attr->read(iov[i].iov_base, iov[i].iov_len, 330 offset, node->private); 331 offset += rcount; 332 count += rcount; 333 /* If we read less than requested. we are done */ 334 if (rcount < iov[i].iov_len) { 335 break; 336 } 337 } 338 return count; 339 } 340 341 static int synth_truncate(FsContext *ctx, V9fsPath *path, off_t offset) 342 { 343 errno = ENOSYS; 344 return -1; 345 } 346 347 static int synth_chmod(FsContext *fs_ctx, V9fsPath *path, FsCred *credp) 348 { 349 errno = EPERM; 350 return -1; 351 } 352 353 static int synth_mknod(FsContext *fs_ctx, V9fsPath *path, 354 const char *buf, FsCred *credp) 355 { 356 errno = EPERM; 357 return -1; 358 } 359 360 static int synth_mkdir(FsContext *fs_ctx, V9fsPath *path, 361 const char *buf, FsCred *credp) 362 { 363 errno = EPERM; 364 return -1; 365 } 366 367 static ssize_t synth_readlink(FsContext *fs_ctx, V9fsPath *path, 368 char *buf, size_t bufsz) 369 { 370 errno = ENOSYS; 371 return -1; 372 } 373 374 static int synth_symlink(FsContext *fs_ctx, const char *oldpath, 375 V9fsPath *newpath, const char *buf, FsCred *credp) 376 { 377 errno = EPERM; 378 return -1; 379 } 380 381 static int synth_link(FsContext *fs_ctx, V9fsPath *oldpath, 382 V9fsPath *newpath, const char *buf) 383 { 384 errno = EPERM; 385 return -1; 386 } 387 388 static int synth_rename(FsContext *ctx, const char *oldpath, 389 const char *newpath) 390 { 391 errno = EPERM; 392 return -1; 393 } 394 395 static int synth_chown(FsContext *fs_ctx, V9fsPath *path, FsCred *credp) 396 { 397 errno = EPERM; 398 return -1; 399 } 400 401 static int synth_utimensat(FsContext *fs_ctx, V9fsPath *path, 402 const struct timespec *buf) 403 { 404 errno = EPERM; 405 return 0; 406 } 407 408 static int synth_remove(FsContext *ctx, const char *path) 409 { 410 errno = EPERM; 411 return -1; 412 } 413 414 static int synth_fsync(FsContext *ctx, int fid_type, 415 V9fsFidOpenState *fs, int datasync) 416 { 417 errno = ENOSYS; 418 return 0; 419 } 420 421 static int synth_statfs(FsContext *s, V9fsPath *fs_path, 422 struct statfs *stbuf) 423 { 424 stbuf->f_type = 0xABCD; 425 stbuf->f_bsize = 512; 426 stbuf->f_blocks = 0; 427 stbuf->f_files = synth_node_count; 428 stbuf->f_namelen = NAME_MAX; 429 return 0; 430 } 431 432 static ssize_t synth_lgetxattr(FsContext *ctx, V9fsPath *path, 433 const char *name, void *value, size_t size) 434 { 435 errno = ENOTSUP; 436 return -1; 437 } 438 439 static ssize_t synth_llistxattr(FsContext *ctx, V9fsPath *path, 440 void *value, size_t size) 441 { 442 errno = ENOTSUP; 443 return -1; 444 } 445 446 static int synth_lsetxattr(FsContext *ctx, V9fsPath *path, 447 const char *name, void *value, 448 size_t size, int flags) 449 { 450 errno = ENOTSUP; 451 return -1; 452 } 453 454 static int synth_lremovexattr(FsContext *ctx, 455 V9fsPath *path, const char *name) 456 { 457 errno = ENOTSUP; 458 return -1; 459 } 460 461 static int synth_name_to_path(FsContext *ctx, V9fsPath *dir_path, 462 const char *name, V9fsPath *target) 463 { 464 V9fsSynthNode *node; 465 V9fsSynthNode *dir_node; 466 467 /* "." and ".." are not allowed */ 468 if (!strcmp(name, ".") || !strcmp(name, "..")) { 469 errno = EINVAL; 470 return -1; 471 472 } 473 if (!dir_path) { 474 dir_node = &synth_root; 475 } else { 476 dir_node = *(V9fsSynthNode **)dir_path->data; 477 } 478 if (!strcmp(name, "/")) { 479 node = dir_node; 480 goto out; 481 } 482 /* search for the name in the childern */ 483 rcu_read_lock(); 484 QLIST_FOREACH(node, &dir_node->child, sibling) { 485 if (!strcmp(node->name, name)) { 486 break; 487 } 488 } 489 rcu_read_unlock(); 490 491 if (!node) { 492 errno = ENOENT; 493 return -1; 494 } 495 out: 496 /* Copy the node pointer to fid */ 497 target->data = g_memdup(&node, sizeof(void *)); 498 target->size = sizeof(void *); 499 return 0; 500 } 501 502 static int synth_renameat(FsContext *ctx, V9fsPath *olddir, 503 const char *old_name, V9fsPath *newdir, 504 const char *new_name) 505 { 506 errno = EPERM; 507 return -1; 508 } 509 510 static int synth_unlinkat(FsContext *ctx, V9fsPath *dir, 511 const char *name, int flags) 512 { 513 errno = EPERM; 514 return -1; 515 } 516 517 static int synth_init(FsContext *ctx) 518 { 519 QLIST_INIT(&synth_root.child); 520 qemu_mutex_init(&synth_mutex); 521 522 /* Add "." and ".." entries for root */ 523 v9fs_add_dir_node(&synth_root, synth_root.attr->mode, 524 "..", synth_root.attr, synth_root.attr->inode); 525 v9fs_add_dir_node(&synth_root, synth_root.attr->mode, 526 ".", synth_root.attr, synth_root.attr->inode); 527 528 /* Mark the subsystem is ready for use */ 529 synth_fs = 1; 530 return 0; 531 } 532 533 FileOperations synth_ops = { 534 .init = synth_init, 535 .lstat = synth_lstat, 536 .readlink = synth_readlink, 537 .close = synth_close, 538 .closedir = synth_closedir, 539 .open = synth_open, 540 .opendir = synth_opendir, 541 .rewinddir = synth_rewinddir, 542 .telldir = synth_telldir, 543 .readdir = synth_readdir, 544 .seekdir = synth_seekdir, 545 .preadv = synth_preadv, 546 .pwritev = synth_pwritev, 547 .chmod = synth_chmod, 548 .mknod = synth_mknod, 549 .mkdir = synth_mkdir, 550 .fstat = synth_fstat, 551 .open2 = synth_open2, 552 .symlink = synth_symlink, 553 .link = synth_link, 554 .truncate = synth_truncate, 555 .rename = synth_rename, 556 .chown = synth_chown, 557 .utimensat = synth_utimensat, 558 .remove = synth_remove, 559 .fsync = synth_fsync, 560 .statfs = synth_statfs, 561 .lgetxattr = synth_lgetxattr, 562 .llistxattr = synth_llistxattr, 563 .lsetxattr = synth_lsetxattr, 564 .lremovexattr = synth_lremovexattr, 565 .name_to_path = synth_name_to_path, 566 .renameat = synth_renameat, 567 .unlinkat = synth_unlinkat, 568 }; 569