1 /* 2 * linux/fs/proc/inode.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 #include <linux/time.h> 8 #include <linux/proc_fs.h> 9 #include <linux/kernel.h> 10 #include <linux/mm.h> 11 #include <linux/string.h> 12 #include <linux/stat.h> 13 #include <linux/completion.h> 14 #include <linux/poll.h> 15 #include <linux/file.h> 16 #include <linux/limits.h> 17 #include <linux/init.h> 18 #include <linux/module.h> 19 #include <linux/smp_lock.h> 20 21 #include <asm/system.h> 22 #include <asm/uaccess.h> 23 24 #include "internal.h" 25 26 struct proc_dir_entry *de_get(struct proc_dir_entry *de) 27 { 28 if (de) 29 atomic_inc(&de->count); 30 return de; 31 } 32 33 /* 34 * Decrements the use count and checks for deferred deletion. 35 */ 36 void de_put(struct proc_dir_entry *de) 37 { 38 if (de) { 39 lock_kernel(); 40 if (!atomic_read(&de->count)) { 41 printk("de_put: entry %s already free!\n", de->name); 42 unlock_kernel(); 43 return; 44 } 45 46 if (atomic_dec_and_test(&de->count)) { 47 if (de->deleted) { 48 printk("de_put: deferred delete of %s\n", 49 de->name); 50 free_proc_entry(de); 51 } 52 } 53 unlock_kernel(); 54 } 55 } 56 57 /* 58 * Decrement the use count of the proc_dir_entry. 59 */ 60 static void proc_delete_inode(struct inode *inode) 61 { 62 struct proc_dir_entry *de; 63 64 truncate_inode_pages(&inode->i_data, 0); 65 66 /* Stop tracking associated processes */ 67 put_pid(PROC_I(inode)->pid); 68 69 /* Let go of any associated proc directory entry */ 70 de = PROC_I(inode)->pde; 71 if (de) { 72 if (de->owner) 73 module_put(de->owner); 74 de_put(de); 75 } 76 clear_inode(inode); 77 } 78 79 struct vfsmount *proc_mnt; 80 81 static void proc_read_inode(struct inode * inode) 82 { 83 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 84 } 85 86 static struct kmem_cache * proc_inode_cachep; 87 88 static struct inode *proc_alloc_inode(struct super_block *sb) 89 { 90 struct proc_inode *ei; 91 struct inode *inode; 92 93 ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL); 94 if (!ei) 95 return NULL; 96 ei->pid = NULL; 97 ei->fd = 0; 98 ei->op.proc_get_link = NULL; 99 ei->pde = NULL; 100 inode = &ei->vfs_inode; 101 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 102 return inode; 103 } 104 105 static void proc_destroy_inode(struct inode *inode) 106 { 107 kmem_cache_free(proc_inode_cachep, PROC_I(inode)); 108 } 109 110 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags) 111 { 112 struct proc_inode *ei = (struct proc_inode *) foo; 113 114 inode_init_once(&ei->vfs_inode); 115 } 116 117 int __init proc_init_inodecache(void) 118 { 119 proc_inode_cachep = kmem_cache_create("proc_inode_cache", 120 sizeof(struct proc_inode), 121 0, (SLAB_RECLAIM_ACCOUNT| 122 SLAB_MEM_SPREAD), 123 init_once); 124 if (proc_inode_cachep == NULL) 125 return -ENOMEM; 126 return 0; 127 } 128 129 static int proc_remount(struct super_block *sb, int *flags, char *data) 130 { 131 *flags |= MS_NODIRATIME; 132 return 0; 133 } 134 135 static const struct super_operations proc_sops = { 136 .alloc_inode = proc_alloc_inode, 137 .destroy_inode = proc_destroy_inode, 138 .read_inode = proc_read_inode, 139 .drop_inode = generic_delete_inode, 140 .delete_inode = proc_delete_inode, 141 .statfs = simple_statfs, 142 .remount_fs = proc_remount, 143 }; 144 145 static void pde_users_dec(struct proc_dir_entry *pde) 146 { 147 spin_lock(&pde->pde_unload_lock); 148 pde->pde_users--; 149 if (pde->pde_unload_completion && pde->pde_users == 0) 150 complete(pde->pde_unload_completion); 151 spin_unlock(&pde->pde_unload_lock); 152 } 153 154 static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) 155 { 156 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 157 loff_t rv = -EINVAL; 158 loff_t (*llseek)(struct file *, loff_t, int); 159 160 spin_lock(&pde->pde_unload_lock); 161 /* 162 * remove_proc_entry() is going to delete PDE (as part of module 163 * cleanup sequence). No new callers into module allowed. 164 */ 165 if (!pde->proc_fops) { 166 spin_unlock(&pde->pde_unload_lock); 167 return rv; 168 } 169 /* 170 * Bump refcount so that remove_proc_entry will wail for ->llseek to 171 * complete. 172 */ 173 pde->pde_users++; 174 /* 175 * Save function pointer under lock, to protect against ->proc_fops 176 * NULL'ifying right after ->pde_unload_lock is dropped. 177 */ 178 llseek = pde->proc_fops->llseek; 179 spin_unlock(&pde->pde_unload_lock); 180 181 if (!llseek) 182 llseek = default_llseek; 183 rv = llseek(file, offset, whence); 184 185 pde_users_dec(pde); 186 return rv; 187 } 188 189 static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 190 { 191 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 192 ssize_t rv = -EIO; 193 ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); 194 195 spin_lock(&pde->pde_unload_lock); 196 if (!pde->proc_fops) { 197 spin_unlock(&pde->pde_unload_lock); 198 return rv; 199 } 200 pde->pde_users++; 201 read = pde->proc_fops->read; 202 spin_unlock(&pde->pde_unload_lock); 203 204 if (read) 205 rv = read(file, buf, count, ppos); 206 207 pde_users_dec(pde); 208 return rv; 209 } 210 211 static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 212 { 213 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 214 ssize_t rv = -EIO; 215 ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); 216 217 spin_lock(&pde->pde_unload_lock); 218 if (!pde->proc_fops) { 219 spin_unlock(&pde->pde_unload_lock); 220 return rv; 221 } 222 pde->pde_users++; 223 write = pde->proc_fops->write; 224 spin_unlock(&pde->pde_unload_lock); 225 226 if (write) 227 rv = write(file, buf, count, ppos); 228 229 pde_users_dec(pde); 230 return rv; 231 } 232 233 static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) 234 { 235 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 236 unsigned int rv = DEFAULT_POLLMASK; 237 unsigned int (*poll)(struct file *, struct poll_table_struct *); 238 239 spin_lock(&pde->pde_unload_lock); 240 if (!pde->proc_fops) { 241 spin_unlock(&pde->pde_unload_lock); 242 return rv; 243 } 244 pde->pde_users++; 245 poll = pde->proc_fops->poll; 246 spin_unlock(&pde->pde_unload_lock); 247 248 if (poll) 249 rv = poll(file, pts); 250 251 pde_users_dec(pde); 252 return rv; 253 } 254 255 static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 256 { 257 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 258 long rv = -ENOTTY; 259 long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long); 260 int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long); 261 262 spin_lock(&pde->pde_unload_lock); 263 if (!pde->proc_fops) { 264 spin_unlock(&pde->pde_unload_lock); 265 return rv; 266 } 267 pde->pde_users++; 268 unlocked_ioctl = pde->proc_fops->unlocked_ioctl; 269 ioctl = pde->proc_fops->ioctl; 270 spin_unlock(&pde->pde_unload_lock); 271 272 if (unlocked_ioctl) { 273 rv = unlocked_ioctl(file, cmd, arg); 274 if (rv == -ENOIOCTLCMD) 275 rv = -EINVAL; 276 } else if (ioctl) { 277 lock_kernel(); 278 rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg); 279 unlock_kernel(); 280 } 281 282 pde_users_dec(pde); 283 return rv; 284 } 285 286 #ifdef CONFIG_COMPAT 287 static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 288 { 289 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 290 long rv = -ENOTTY; 291 long (*compat_ioctl)(struct file *, unsigned int, unsigned long); 292 293 spin_lock(&pde->pde_unload_lock); 294 if (!pde->proc_fops) { 295 spin_unlock(&pde->pde_unload_lock); 296 return rv; 297 } 298 pde->pde_users++; 299 compat_ioctl = pde->proc_fops->compat_ioctl; 300 spin_unlock(&pde->pde_unload_lock); 301 302 if (compat_ioctl) 303 rv = compat_ioctl(file, cmd, arg); 304 305 pde_users_dec(pde); 306 return rv; 307 } 308 #endif 309 310 static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) 311 { 312 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 313 int rv = -EIO; 314 int (*mmap)(struct file *, struct vm_area_struct *); 315 316 spin_lock(&pde->pde_unload_lock); 317 if (!pde->proc_fops) { 318 spin_unlock(&pde->pde_unload_lock); 319 return rv; 320 } 321 pde->pde_users++; 322 mmap = pde->proc_fops->mmap; 323 spin_unlock(&pde->pde_unload_lock); 324 325 if (mmap) 326 rv = mmap(file, vma); 327 328 pde_users_dec(pde); 329 return rv; 330 } 331 332 static int proc_reg_open(struct inode *inode, struct file *file) 333 { 334 struct proc_dir_entry *pde = PDE(inode); 335 int rv = 0; 336 int (*open)(struct inode *, struct file *); 337 338 spin_lock(&pde->pde_unload_lock); 339 if (!pde->proc_fops) { 340 spin_unlock(&pde->pde_unload_lock); 341 return rv; 342 } 343 pde->pde_users++; 344 open = pde->proc_fops->open; 345 spin_unlock(&pde->pde_unload_lock); 346 347 if (open) 348 rv = open(inode, file); 349 350 pde_users_dec(pde); 351 return rv; 352 } 353 354 static int proc_reg_release(struct inode *inode, struct file *file) 355 { 356 struct proc_dir_entry *pde = PDE(inode); 357 int rv = 0; 358 int (*release)(struct inode *, struct file *); 359 360 spin_lock(&pde->pde_unload_lock); 361 if (!pde->proc_fops) { 362 spin_unlock(&pde->pde_unload_lock); 363 return rv; 364 } 365 pde->pde_users++; 366 release = pde->proc_fops->release; 367 spin_unlock(&pde->pde_unload_lock); 368 369 if (release) 370 rv = release(inode, file); 371 372 pde_users_dec(pde); 373 return rv; 374 } 375 376 static const struct file_operations proc_reg_file_ops = { 377 .llseek = proc_reg_llseek, 378 .read = proc_reg_read, 379 .write = proc_reg_write, 380 .poll = proc_reg_poll, 381 .unlocked_ioctl = proc_reg_unlocked_ioctl, 382 #ifdef CONFIG_COMPAT 383 .compat_ioctl = proc_reg_compat_ioctl, 384 #endif 385 .mmap = proc_reg_mmap, 386 .open = proc_reg_open, 387 .release = proc_reg_release, 388 }; 389 390 #ifdef CONFIG_COMPAT 391 static const struct file_operations proc_reg_file_ops_no_compat = { 392 .llseek = proc_reg_llseek, 393 .read = proc_reg_read, 394 .write = proc_reg_write, 395 .poll = proc_reg_poll, 396 .unlocked_ioctl = proc_reg_unlocked_ioctl, 397 .mmap = proc_reg_mmap, 398 .open = proc_reg_open, 399 .release = proc_reg_release, 400 }; 401 #endif 402 403 struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, 404 struct proc_dir_entry *de) 405 { 406 struct inode * inode; 407 408 if (de != NULL && !try_module_get(de->owner)) 409 goto out_mod; 410 411 inode = iget(sb, ino); 412 if (!inode) 413 goto out_ino; 414 415 PROC_I(inode)->fd = 0; 416 PROC_I(inode)->pde = de; 417 if (de) { 418 if (de->mode) { 419 inode->i_mode = de->mode; 420 inode->i_uid = de->uid; 421 inode->i_gid = de->gid; 422 } 423 if (de->size) 424 inode->i_size = de->size; 425 if (de->nlink) 426 inode->i_nlink = de->nlink; 427 if (de->proc_iops) 428 inode->i_op = de->proc_iops; 429 if (de->proc_fops) { 430 if (S_ISREG(inode->i_mode)) { 431 #ifdef CONFIG_COMPAT 432 if (!de->proc_fops->compat_ioctl) 433 inode->i_fop = 434 &proc_reg_file_ops_no_compat; 435 else 436 #endif 437 inode->i_fop = &proc_reg_file_ops; 438 } 439 else 440 inode->i_fop = de->proc_fops; 441 } 442 } 443 444 return inode; 445 446 out_ino: 447 if (de != NULL) 448 module_put(de->owner); 449 out_mod: 450 return NULL; 451 } 452 453 int proc_fill_super(struct super_block *s, void *data, int silent) 454 { 455 struct inode * root_inode; 456 457 s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; 458 s->s_blocksize = 1024; 459 s->s_blocksize_bits = 10; 460 s->s_magic = PROC_SUPER_MAGIC; 461 s->s_op = &proc_sops; 462 s->s_time_gran = 1; 463 464 de_get(&proc_root); 465 root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); 466 if (!root_inode) 467 goto out_no_root; 468 root_inode->i_uid = 0; 469 root_inode->i_gid = 0; 470 s->s_root = d_alloc_root(root_inode); 471 if (!s->s_root) 472 goto out_no_root; 473 return 0; 474 475 out_no_root: 476 printk("proc_read_super: get root inode failed\n"); 477 iput(root_inode); 478 de_put(&proc_root); 479 return -ENOMEM; 480 } 481 MODULE_LICENSE("GPL"); 482