1 // SPDX-License-Identifier: GPL-1.0+ 2 /* 3 * Hypervisor filesystem for Linux on s390. 4 * 5 * Copyright IBM Corp. 2006, 2008 6 * Author(s): Michael Holzheu <holzheu@de.ibm.com> 7 */ 8 9 #define KMSG_COMPONENT "hypfs" 10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 11 12 #include <linux/types.h> 13 #include <linux/errno.h> 14 #include <linux/fs.h> 15 #include <linux/fs_context.h> 16 #include <linux/fs_parser.h> 17 #include <linux/namei.h> 18 #include <linux/vfs.h> 19 #include <linux/slab.h> 20 #include <linux/pagemap.h> 21 #include <linux/time.h> 22 #include <linux/sysfs.h> 23 #include <linux/init.h> 24 #include <linux/kobject.h> 25 #include <linux/seq_file.h> 26 #include <linux/uio.h> 27 #include <asm/ebcdic.h> 28 #include "hypfs.h" 29 30 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */ 31 #define TMP_SIZE 64 /* size of temporary buffers */ 32 33 static struct dentry *hypfs_create_update_file(struct dentry *dir); 34 35 struct hypfs_sb_info { 36 kuid_t uid; /* uid used for files and dirs */ 37 kgid_t gid; /* gid used for files and dirs */ 38 struct dentry *update_file; /* file to trigger update */ 39 time64_t last_update; /* last update, CLOCK_MONOTONIC time */ 40 struct mutex lock; /* lock to protect update process */ 41 }; 42 43 static const struct file_operations hypfs_file_ops; 44 static struct file_system_type hypfs_type; 45 static const struct super_operations hypfs_s_ops; 46 47 /* start of list of all dentries, which have to be deleted on update */ 48 static struct dentry *hypfs_last_dentry; 49 50 static void hypfs_update_update(struct super_block *sb) 51 { 52 struct hypfs_sb_info *sb_info = sb->s_fs_info; 53 struct inode *inode = d_inode(sb_info->update_file); 54 55 sb_info->last_update = ktime_get_seconds(); 56 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); 57 } 58 59 /* directory tree removal functions */ 60 61 static void hypfs_add_dentry(struct dentry *dentry) 62 { 63 dentry->d_fsdata = hypfs_last_dentry; 64 hypfs_last_dentry = dentry; 65 } 66 67 static void hypfs_remove(struct dentry *dentry) 68 { 69 struct dentry *parent; 70 71 parent = dentry->d_parent; 72 inode_lock(d_inode(parent)); 73 if (simple_positive(dentry)) { 74 if (d_is_dir(dentry)) 75 simple_rmdir(d_inode(parent), dentry); 76 else 77 simple_unlink(d_inode(parent), dentry); 78 } 79 d_drop(dentry); 80 dput(dentry); 81 inode_unlock(d_inode(parent)); 82 } 83 84 static void hypfs_delete_tree(struct dentry *root) 85 { 86 while (hypfs_last_dentry) { 87 struct dentry *next_dentry; 88 next_dentry = hypfs_last_dentry->d_fsdata; 89 hypfs_remove(hypfs_last_dentry); 90 hypfs_last_dentry = next_dentry; 91 } 92 } 93 94 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode) 95 { 96 struct inode *ret = new_inode(sb); 97 98 if (ret) { 99 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 100 ret->i_ino = get_next_ino(); 101 ret->i_mode = mode; 102 ret->i_uid = hypfs_info->uid; 103 ret->i_gid = hypfs_info->gid; 104 ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret); 105 if (S_ISDIR(mode)) 106 set_nlink(ret, 2); 107 } 108 return ret; 109 } 110 111 static void hypfs_evict_inode(struct inode *inode) 112 { 113 clear_inode(inode); 114 kfree(inode->i_private); 115 } 116 117 static int hypfs_open(struct inode *inode, struct file *filp) 118 { 119 char *data = file_inode(filp)->i_private; 120 struct hypfs_sb_info *fs_info; 121 122 if (filp->f_mode & FMODE_WRITE) { 123 if (!(inode->i_mode & S_IWUGO)) 124 return -EACCES; 125 } 126 if (filp->f_mode & FMODE_READ) { 127 if (!(inode->i_mode & S_IRUGO)) 128 return -EACCES; 129 } 130 131 fs_info = inode->i_sb->s_fs_info; 132 if(data) { 133 mutex_lock(&fs_info->lock); 134 filp->private_data = kstrdup(data, GFP_KERNEL); 135 if (!filp->private_data) { 136 mutex_unlock(&fs_info->lock); 137 return -ENOMEM; 138 } 139 mutex_unlock(&fs_info->lock); 140 } 141 return nonseekable_open(inode, filp); 142 } 143 144 static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to) 145 { 146 struct file *file = iocb->ki_filp; 147 char *data = file->private_data; 148 size_t available = strlen(data); 149 loff_t pos = iocb->ki_pos; 150 size_t count; 151 152 if (pos < 0) 153 return -EINVAL; 154 if (pos >= available || !iov_iter_count(to)) 155 return 0; 156 count = copy_to_iter(data + pos, available - pos, to); 157 if (!count) 158 return -EFAULT; 159 iocb->ki_pos = pos + count; 160 file_accessed(file); 161 return count; 162 } 163 164 static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from) 165 { 166 int rc; 167 struct super_block *sb = file_inode(iocb->ki_filp)->i_sb; 168 struct hypfs_sb_info *fs_info = sb->s_fs_info; 169 size_t count = iov_iter_count(from); 170 171 /* 172 * Currently we only allow one update per second for two reasons: 173 * 1. diag 204 is VERY expensive 174 * 2. If several processes do updates in parallel and then read the 175 * hypfs data, the likelihood of collisions is reduced, if we restrict 176 * the minimum update interval. A collision occurs, if during the 177 * data gathering of one process another process triggers an update 178 * If the first process wants to ensure consistent data, it has 179 * to restart data collection in this case. 180 */ 181 mutex_lock(&fs_info->lock); 182 if (fs_info->last_update == ktime_get_seconds()) { 183 rc = -EBUSY; 184 goto out; 185 } 186 hypfs_delete_tree(sb->s_root); 187 if (MACHINE_IS_VM) 188 rc = hypfs_vm_create_files(sb->s_root); 189 else 190 rc = hypfs_diag_create_files(sb->s_root); 191 if (rc) { 192 pr_err("Updating the hypfs tree failed\n"); 193 hypfs_delete_tree(sb->s_root); 194 goto out; 195 } 196 hypfs_update_update(sb); 197 rc = count; 198 iov_iter_advance(from, count); 199 out: 200 mutex_unlock(&fs_info->lock); 201 return rc; 202 } 203 204 static int hypfs_release(struct inode *inode, struct file *filp) 205 { 206 kfree(filp->private_data); 207 return 0; 208 } 209 210 enum { Opt_uid, Opt_gid, }; 211 212 static const struct fs_parameter_spec hypfs_param_specs[] = { 213 fsparam_u32("gid", Opt_gid), 214 fsparam_u32("uid", Opt_uid), 215 {} 216 }; 217 218 static const struct fs_parameter_description hypfs_fs_parameters = { 219 .name = "hypfs", 220 .specs = hypfs_param_specs, 221 }; 222 223 static int hypfs_parse_param(struct fs_context *fc, struct fs_parameter *param) 224 { 225 struct hypfs_sb_info *hypfs_info = fc->s_fs_info; 226 struct fs_parse_result result; 227 kuid_t uid; 228 kgid_t gid; 229 int opt; 230 231 opt = fs_parse(fc, &hypfs_fs_parameters, param, &result); 232 if (opt < 0) 233 return opt; 234 235 switch (opt) { 236 case Opt_uid: 237 uid = make_kuid(current_user_ns(), result.uint_32); 238 if (!uid_valid(uid)) 239 return invalf(fc, "Unknown uid"); 240 hypfs_info->uid = uid; 241 break; 242 case Opt_gid: 243 gid = make_kgid(current_user_ns(), result.uint_32); 244 if (!gid_valid(gid)) 245 return invalf(fc, "Unknown gid"); 246 hypfs_info->gid = gid; 247 break; 248 } 249 return 0; 250 } 251 252 static int hypfs_show_options(struct seq_file *s, struct dentry *root) 253 { 254 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info; 255 256 seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid)); 257 seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid)); 258 return 0; 259 } 260 261 static int hypfs_fill_super(struct super_block *sb, struct fs_context *fc) 262 { 263 struct hypfs_sb_info *sbi = sb->s_fs_info; 264 struct inode *root_inode; 265 struct dentry *root_dentry, *update_file; 266 int rc; 267 268 sb->s_blocksize = PAGE_SIZE; 269 sb->s_blocksize_bits = PAGE_SHIFT; 270 sb->s_magic = HYPFS_MAGIC; 271 sb->s_op = &hypfs_s_ops; 272 273 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 274 if (!root_inode) 275 return -ENOMEM; 276 root_inode->i_op = &simple_dir_inode_operations; 277 root_inode->i_fop = &simple_dir_operations; 278 sb->s_root = root_dentry = d_make_root(root_inode); 279 if (!root_dentry) 280 return -ENOMEM; 281 if (MACHINE_IS_VM) 282 rc = hypfs_vm_create_files(root_dentry); 283 else 284 rc = hypfs_diag_create_files(root_dentry); 285 if (rc) 286 return rc; 287 update_file = hypfs_create_update_file(root_dentry); 288 if (IS_ERR(update_file)) 289 return PTR_ERR(update_file); 290 sbi->update_file = update_file; 291 hypfs_update_update(sb); 292 pr_info("Hypervisor filesystem mounted\n"); 293 return 0; 294 } 295 296 static int hypfs_get_tree(struct fs_context *fc) 297 { 298 return get_tree_single(fc, hypfs_fill_super); 299 } 300 301 static void hypfs_free_fc(struct fs_context *fc) 302 { 303 kfree(fc->s_fs_info); 304 } 305 306 static const struct fs_context_operations hypfs_context_ops = { 307 .free = hypfs_free_fc, 308 .parse_param = hypfs_parse_param, 309 .get_tree = hypfs_get_tree, 310 }; 311 312 static int hypfs_init_fs_context(struct fs_context *fc) 313 { 314 struct hypfs_sb_info *sbi; 315 316 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 317 if (!sbi) 318 return -ENOMEM; 319 320 mutex_init(&sbi->lock); 321 sbi->uid = current_uid(); 322 sbi->gid = current_gid(); 323 324 fc->s_fs_info = sbi; 325 fc->ops = &hypfs_context_ops; 326 return 0; 327 } 328 329 static void hypfs_kill_super(struct super_block *sb) 330 { 331 struct hypfs_sb_info *sb_info = sb->s_fs_info; 332 333 if (sb->s_root) 334 hypfs_delete_tree(sb->s_root); 335 if (sb_info && sb_info->update_file) 336 hypfs_remove(sb_info->update_file); 337 kfree(sb->s_fs_info); 338 sb->s_fs_info = NULL; 339 kill_litter_super(sb); 340 } 341 342 static struct dentry *hypfs_create_file(struct dentry *parent, const char *name, 343 char *data, umode_t mode) 344 { 345 struct dentry *dentry; 346 struct inode *inode; 347 348 inode_lock(d_inode(parent)); 349 dentry = lookup_one_len(name, parent, strlen(name)); 350 if (IS_ERR(dentry)) { 351 dentry = ERR_PTR(-ENOMEM); 352 goto fail; 353 } 354 inode = hypfs_make_inode(parent->d_sb, mode); 355 if (!inode) { 356 dput(dentry); 357 dentry = ERR_PTR(-ENOMEM); 358 goto fail; 359 } 360 if (S_ISREG(mode)) { 361 inode->i_fop = &hypfs_file_ops; 362 if (data) 363 inode->i_size = strlen(data); 364 else 365 inode->i_size = 0; 366 } else if (S_ISDIR(mode)) { 367 inode->i_op = &simple_dir_inode_operations; 368 inode->i_fop = &simple_dir_operations; 369 inc_nlink(d_inode(parent)); 370 } else 371 BUG(); 372 inode->i_private = data; 373 d_instantiate(dentry, inode); 374 dget(dentry); 375 fail: 376 inode_unlock(d_inode(parent)); 377 return dentry; 378 } 379 380 struct dentry *hypfs_mkdir(struct dentry *parent, const char *name) 381 { 382 struct dentry *dentry; 383 384 dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE); 385 if (IS_ERR(dentry)) 386 return dentry; 387 hypfs_add_dentry(dentry); 388 return dentry; 389 } 390 391 static struct dentry *hypfs_create_update_file(struct dentry *dir) 392 { 393 struct dentry *dentry; 394 395 dentry = hypfs_create_file(dir, "update", NULL, 396 S_IFREG | UPDATE_FILE_MODE); 397 /* 398 * We do not put the update file on the 'delete' list with 399 * hypfs_add_dentry(), since it should not be removed when the tree 400 * is updated. 401 */ 402 return dentry; 403 } 404 405 struct dentry *hypfs_create_u64(struct dentry *dir, 406 const char *name, __u64 value) 407 { 408 char *buffer; 409 char tmp[TMP_SIZE]; 410 struct dentry *dentry; 411 412 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); 413 buffer = kstrdup(tmp, GFP_KERNEL); 414 if (!buffer) 415 return ERR_PTR(-ENOMEM); 416 dentry = 417 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); 418 if (IS_ERR(dentry)) { 419 kfree(buffer); 420 return ERR_PTR(-ENOMEM); 421 } 422 hypfs_add_dentry(dentry); 423 return dentry; 424 } 425 426 struct dentry *hypfs_create_str(struct dentry *dir, 427 const char *name, char *string) 428 { 429 char *buffer; 430 struct dentry *dentry; 431 432 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 433 if (!buffer) 434 return ERR_PTR(-ENOMEM); 435 sprintf(buffer, "%s\n", string); 436 dentry = 437 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); 438 if (IS_ERR(dentry)) { 439 kfree(buffer); 440 return ERR_PTR(-ENOMEM); 441 } 442 hypfs_add_dentry(dentry); 443 return dentry; 444 } 445 446 static const struct file_operations hypfs_file_ops = { 447 .open = hypfs_open, 448 .release = hypfs_release, 449 .read_iter = hypfs_read_iter, 450 .write_iter = hypfs_write_iter, 451 .llseek = no_llseek, 452 }; 453 454 static struct file_system_type hypfs_type = { 455 .owner = THIS_MODULE, 456 .name = "s390_hypfs", 457 .init_fs_context = hypfs_init_fs_context, 458 .parameters = &hypfs_fs_parameters, 459 .kill_sb = hypfs_kill_super 460 }; 461 462 static const struct super_operations hypfs_s_ops = { 463 .statfs = simple_statfs, 464 .evict_inode = hypfs_evict_inode, 465 .show_options = hypfs_show_options, 466 }; 467 468 static int __init hypfs_init(void) 469 { 470 int rc; 471 472 hypfs_dbfs_init(); 473 474 if (hypfs_diag_init()) { 475 rc = -ENODATA; 476 goto fail_dbfs_exit; 477 } 478 if (hypfs_vm_init()) { 479 rc = -ENODATA; 480 goto fail_hypfs_diag_exit; 481 } 482 hypfs_sprp_init(); 483 if (hypfs_diag0c_init()) { 484 rc = -ENODATA; 485 goto fail_hypfs_sprp_exit; 486 } 487 rc = sysfs_create_mount_point(hypervisor_kobj, "s390"); 488 if (rc) 489 goto fail_hypfs_diag0c_exit; 490 rc = register_filesystem(&hypfs_type); 491 if (rc) 492 goto fail_filesystem; 493 return 0; 494 495 fail_filesystem: 496 sysfs_remove_mount_point(hypervisor_kobj, "s390"); 497 fail_hypfs_diag0c_exit: 498 hypfs_diag0c_exit(); 499 fail_hypfs_sprp_exit: 500 hypfs_sprp_exit(); 501 hypfs_vm_exit(); 502 fail_hypfs_diag_exit: 503 hypfs_diag_exit(); 504 fail_dbfs_exit: 505 hypfs_dbfs_exit(); 506 pr_err("Initialization of hypfs failed with rc=%i\n", rc); 507 return rc; 508 } 509 device_initcall(hypfs_init) 510