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/namei.h> 16 #include <linux/vfs.h> 17 #include <linux/slab.h> 18 #include <linux/pagemap.h> 19 #include <linux/time.h> 20 #include <linux/parser.h> 21 #include <linux/sysfs.h> 22 #include <linux/init.h> 23 #include <linux/kobject.h> 24 #include <linux/seq_file.h> 25 #include <linux/mount.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 time_t last_update; /* last update time in secs since 1970 */ 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 = 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_delete(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 == 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, opt_err }; 211 212 static const match_table_t hypfs_tokens = { 213 {opt_uid, "uid=%u"}, 214 {opt_gid, "gid=%u"}, 215 {opt_err, NULL} 216 }; 217 218 static int hypfs_parse_options(char *options, struct super_block *sb) 219 { 220 char *str; 221 substring_t args[MAX_OPT_ARGS]; 222 kuid_t uid; 223 kgid_t gid; 224 225 if (!options) 226 return 0; 227 while ((str = strsep(&options, ",")) != NULL) { 228 int token, option; 229 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 230 231 if (!*str) 232 continue; 233 token = match_token(str, hypfs_tokens, args); 234 switch (token) { 235 case opt_uid: 236 if (match_int(&args[0], &option)) 237 return -EINVAL; 238 uid = make_kuid(current_user_ns(), option); 239 if (!uid_valid(uid)) 240 return -EINVAL; 241 hypfs_info->uid = uid; 242 break; 243 case opt_gid: 244 if (match_int(&args[0], &option)) 245 return -EINVAL; 246 gid = make_kgid(current_user_ns(), option); 247 if (!gid_valid(gid)) 248 return -EINVAL; 249 hypfs_info->gid = gid; 250 break; 251 case opt_err: 252 default: 253 pr_err("%s is not a valid mount option\n", str); 254 return -EINVAL; 255 } 256 } 257 return 0; 258 } 259 260 static int hypfs_show_options(struct seq_file *s, struct dentry *root) 261 { 262 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info; 263 264 seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid)); 265 seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid)); 266 return 0; 267 } 268 269 static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 270 { 271 struct inode *root_inode; 272 struct dentry *root_dentry; 273 int rc = 0; 274 struct hypfs_sb_info *sbi; 275 276 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 277 if (!sbi) 278 return -ENOMEM; 279 mutex_init(&sbi->lock); 280 sbi->uid = current_uid(); 281 sbi->gid = current_gid(); 282 sb->s_fs_info = sbi; 283 sb->s_blocksize = PAGE_SIZE; 284 sb->s_blocksize_bits = PAGE_SHIFT; 285 sb->s_magic = HYPFS_MAGIC; 286 sb->s_op = &hypfs_s_ops; 287 if (hypfs_parse_options(data, sb)) 288 return -EINVAL; 289 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 290 if (!root_inode) 291 return -ENOMEM; 292 root_inode->i_op = &simple_dir_inode_operations; 293 root_inode->i_fop = &simple_dir_operations; 294 sb->s_root = root_dentry = d_make_root(root_inode); 295 if (!root_dentry) 296 return -ENOMEM; 297 if (MACHINE_IS_VM) 298 rc = hypfs_vm_create_files(root_dentry); 299 else 300 rc = hypfs_diag_create_files(root_dentry); 301 if (rc) 302 return rc; 303 sbi->update_file = hypfs_create_update_file(root_dentry); 304 if (IS_ERR(sbi->update_file)) 305 return PTR_ERR(sbi->update_file); 306 hypfs_update_update(sb); 307 pr_info("Hypervisor filesystem mounted\n"); 308 return 0; 309 } 310 311 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags, 312 const char *devname, void *data) 313 { 314 return mount_single(fst, flags, data, hypfs_fill_super); 315 } 316 317 static void hypfs_kill_super(struct super_block *sb) 318 { 319 struct hypfs_sb_info *sb_info = sb->s_fs_info; 320 321 if (sb->s_root) 322 hypfs_delete_tree(sb->s_root); 323 if (sb_info->update_file) 324 hypfs_remove(sb_info->update_file); 325 kfree(sb->s_fs_info); 326 sb->s_fs_info = NULL; 327 kill_litter_super(sb); 328 } 329 330 static struct dentry *hypfs_create_file(struct dentry *parent, const char *name, 331 char *data, umode_t mode) 332 { 333 struct dentry *dentry; 334 struct inode *inode; 335 336 inode_lock(d_inode(parent)); 337 dentry = lookup_one_len(name, parent, strlen(name)); 338 if (IS_ERR(dentry)) { 339 dentry = ERR_PTR(-ENOMEM); 340 goto fail; 341 } 342 inode = hypfs_make_inode(parent->d_sb, mode); 343 if (!inode) { 344 dput(dentry); 345 dentry = ERR_PTR(-ENOMEM); 346 goto fail; 347 } 348 if (S_ISREG(mode)) { 349 inode->i_fop = &hypfs_file_ops; 350 if (data) 351 inode->i_size = strlen(data); 352 else 353 inode->i_size = 0; 354 } else if (S_ISDIR(mode)) { 355 inode->i_op = &simple_dir_inode_operations; 356 inode->i_fop = &simple_dir_operations; 357 inc_nlink(d_inode(parent)); 358 } else 359 BUG(); 360 inode->i_private = data; 361 d_instantiate(dentry, inode); 362 dget(dentry); 363 fail: 364 inode_unlock(d_inode(parent)); 365 return dentry; 366 } 367 368 struct dentry *hypfs_mkdir(struct dentry *parent, const char *name) 369 { 370 struct dentry *dentry; 371 372 dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE); 373 if (IS_ERR(dentry)) 374 return dentry; 375 hypfs_add_dentry(dentry); 376 return dentry; 377 } 378 379 static struct dentry *hypfs_create_update_file(struct dentry *dir) 380 { 381 struct dentry *dentry; 382 383 dentry = hypfs_create_file(dir, "update", NULL, 384 S_IFREG | UPDATE_FILE_MODE); 385 /* 386 * We do not put the update file on the 'delete' list with 387 * hypfs_add_dentry(), since it should not be removed when the tree 388 * is updated. 389 */ 390 return dentry; 391 } 392 393 struct dentry *hypfs_create_u64(struct dentry *dir, 394 const char *name, __u64 value) 395 { 396 char *buffer; 397 char tmp[TMP_SIZE]; 398 struct dentry *dentry; 399 400 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); 401 buffer = kstrdup(tmp, GFP_KERNEL); 402 if (!buffer) 403 return ERR_PTR(-ENOMEM); 404 dentry = 405 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); 406 if (IS_ERR(dentry)) { 407 kfree(buffer); 408 return ERR_PTR(-ENOMEM); 409 } 410 hypfs_add_dentry(dentry); 411 return dentry; 412 } 413 414 struct dentry *hypfs_create_str(struct dentry *dir, 415 const char *name, char *string) 416 { 417 char *buffer; 418 struct dentry *dentry; 419 420 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 421 if (!buffer) 422 return ERR_PTR(-ENOMEM); 423 sprintf(buffer, "%s\n", string); 424 dentry = 425 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); 426 if (IS_ERR(dentry)) { 427 kfree(buffer); 428 return ERR_PTR(-ENOMEM); 429 } 430 hypfs_add_dentry(dentry); 431 return dentry; 432 } 433 434 static const struct file_operations hypfs_file_ops = { 435 .open = hypfs_open, 436 .release = hypfs_release, 437 .read_iter = hypfs_read_iter, 438 .write_iter = hypfs_write_iter, 439 .llseek = no_llseek, 440 }; 441 442 static struct file_system_type hypfs_type = { 443 .owner = THIS_MODULE, 444 .name = "s390_hypfs", 445 .mount = hypfs_mount, 446 .kill_sb = hypfs_kill_super 447 }; 448 449 static const struct super_operations hypfs_s_ops = { 450 .statfs = simple_statfs, 451 .evict_inode = hypfs_evict_inode, 452 .show_options = hypfs_show_options, 453 }; 454 455 static int __init hypfs_init(void) 456 { 457 int rc; 458 459 rc = hypfs_dbfs_init(); 460 if (rc) 461 return rc; 462 if (hypfs_diag_init()) { 463 rc = -ENODATA; 464 goto fail_dbfs_exit; 465 } 466 if (hypfs_vm_init()) { 467 rc = -ENODATA; 468 goto fail_hypfs_diag_exit; 469 } 470 if (hypfs_sprp_init()) { 471 rc = -ENODATA; 472 goto fail_hypfs_vm_exit; 473 } 474 if (hypfs_diag0c_init()) { 475 rc = -ENODATA; 476 goto fail_hypfs_sprp_exit; 477 } 478 rc = sysfs_create_mount_point(hypervisor_kobj, "s390"); 479 if (rc) 480 goto fail_hypfs_diag0c_exit; 481 rc = register_filesystem(&hypfs_type); 482 if (rc) 483 goto fail_filesystem; 484 return 0; 485 486 fail_filesystem: 487 sysfs_remove_mount_point(hypervisor_kobj, "s390"); 488 fail_hypfs_diag0c_exit: 489 hypfs_diag0c_exit(); 490 fail_hypfs_sprp_exit: 491 hypfs_sprp_exit(); 492 fail_hypfs_vm_exit: 493 hypfs_vm_exit(); 494 fail_hypfs_diag_exit: 495 hypfs_diag_exit(); 496 fail_dbfs_exit: 497 hypfs_dbfs_exit(); 498 pr_err("Initialization of hypfs failed with rc=%i\n", rc); 499 return rc; 500 } 501 device_initcall(hypfs_init) 502