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(struct kmem_cache * cachep, void *foo) 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|SLAB_PANIC), 123 init_once); 124 return 0; 125 } 126 127 static int proc_remount(struct super_block *sb, int *flags, char *data) 128 { 129 *flags |= MS_NODIRATIME; 130 return 0; 131 } 132 133 static const struct super_operations proc_sops = { 134 .alloc_inode = proc_alloc_inode, 135 .destroy_inode = proc_destroy_inode, 136 .read_inode = proc_read_inode, 137 .drop_inode = generic_delete_inode, 138 .delete_inode = proc_delete_inode, 139 .statfs = simple_statfs, 140 .remount_fs = proc_remount, 141 }; 142 143 static void pde_users_dec(struct proc_dir_entry *pde) 144 { 145 spin_lock(&pde->pde_unload_lock); 146 pde->pde_users--; 147 if (pde->pde_unload_completion && pde->pde_users == 0) 148 complete(pde->pde_unload_completion); 149 spin_unlock(&pde->pde_unload_lock); 150 } 151 152 static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) 153 { 154 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 155 loff_t rv = -EINVAL; 156 loff_t (*llseek)(struct file *, loff_t, int); 157 158 spin_lock(&pde->pde_unload_lock); 159 /* 160 * remove_proc_entry() is going to delete PDE (as part of module 161 * cleanup sequence). No new callers into module allowed. 162 */ 163 if (!pde->proc_fops) { 164 spin_unlock(&pde->pde_unload_lock); 165 return rv; 166 } 167 /* 168 * Bump refcount so that remove_proc_entry will wail for ->llseek to 169 * complete. 170 */ 171 pde->pde_users++; 172 /* 173 * Save function pointer under lock, to protect against ->proc_fops 174 * NULL'ifying right after ->pde_unload_lock is dropped. 175 */ 176 llseek = pde->proc_fops->llseek; 177 spin_unlock(&pde->pde_unload_lock); 178 179 if (!llseek) 180 llseek = default_llseek; 181 rv = llseek(file, offset, whence); 182 183 pde_users_dec(pde); 184 return rv; 185 } 186 187 static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 188 { 189 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 190 ssize_t rv = -EIO; 191 ssize_t (*read)(struct file *, char __user *, size_t, loff_t *); 192 193 spin_lock(&pde->pde_unload_lock); 194 if (!pde->proc_fops) { 195 spin_unlock(&pde->pde_unload_lock); 196 return rv; 197 } 198 pde->pde_users++; 199 read = pde->proc_fops->read; 200 spin_unlock(&pde->pde_unload_lock); 201 202 if (read) 203 rv = read(file, buf, count, ppos); 204 205 pde_users_dec(pde); 206 return rv; 207 } 208 209 static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 210 { 211 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 212 ssize_t rv = -EIO; 213 ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *); 214 215 spin_lock(&pde->pde_unload_lock); 216 if (!pde->proc_fops) { 217 spin_unlock(&pde->pde_unload_lock); 218 return rv; 219 } 220 pde->pde_users++; 221 write = pde->proc_fops->write; 222 spin_unlock(&pde->pde_unload_lock); 223 224 if (write) 225 rv = write(file, buf, count, ppos); 226 227 pde_users_dec(pde); 228 return rv; 229 } 230 231 static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts) 232 { 233 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 234 unsigned int rv = DEFAULT_POLLMASK; 235 unsigned int (*poll)(struct file *, struct poll_table_struct *); 236 237 spin_lock(&pde->pde_unload_lock); 238 if (!pde->proc_fops) { 239 spin_unlock(&pde->pde_unload_lock); 240 return rv; 241 } 242 pde->pde_users++; 243 poll = pde->proc_fops->poll; 244 spin_unlock(&pde->pde_unload_lock); 245 246 if (poll) 247 rv = poll(file, pts); 248 249 pde_users_dec(pde); 250 return rv; 251 } 252 253 static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 254 { 255 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 256 long rv = -ENOTTY; 257 long (*unlocked_ioctl)(struct file *, unsigned int, unsigned long); 258 int (*ioctl)(struct inode *, struct file *, unsigned int, unsigned long); 259 260 spin_lock(&pde->pde_unload_lock); 261 if (!pde->proc_fops) { 262 spin_unlock(&pde->pde_unload_lock); 263 return rv; 264 } 265 pde->pde_users++; 266 unlocked_ioctl = pde->proc_fops->unlocked_ioctl; 267 ioctl = pde->proc_fops->ioctl; 268 spin_unlock(&pde->pde_unload_lock); 269 270 if (unlocked_ioctl) { 271 rv = unlocked_ioctl(file, cmd, arg); 272 if (rv == -ENOIOCTLCMD) 273 rv = -EINVAL; 274 } else if (ioctl) { 275 lock_kernel(); 276 rv = ioctl(file->f_path.dentry->d_inode, file, cmd, arg); 277 unlock_kernel(); 278 } 279 280 pde_users_dec(pde); 281 return rv; 282 } 283 284 #ifdef CONFIG_COMPAT 285 static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 286 { 287 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 288 long rv = -ENOTTY; 289 long (*compat_ioctl)(struct file *, unsigned int, unsigned long); 290 291 spin_lock(&pde->pde_unload_lock); 292 if (!pde->proc_fops) { 293 spin_unlock(&pde->pde_unload_lock); 294 return rv; 295 } 296 pde->pde_users++; 297 compat_ioctl = pde->proc_fops->compat_ioctl; 298 spin_unlock(&pde->pde_unload_lock); 299 300 if (compat_ioctl) 301 rv = compat_ioctl(file, cmd, arg); 302 303 pde_users_dec(pde); 304 return rv; 305 } 306 #endif 307 308 static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma) 309 { 310 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode); 311 int rv = -EIO; 312 int (*mmap)(struct file *, struct vm_area_struct *); 313 314 spin_lock(&pde->pde_unload_lock); 315 if (!pde->proc_fops) { 316 spin_unlock(&pde->pde_unload_lock); 317 return rv; 318 } 319 pde->pde_users++; 320 mmap = pde->proc_fops->mmap; 321 spin_unlock(&pde->pde_unload_lock); 322 323 if (mmap) 324 rv = mmap(file, vma); 325 326 pde_users_dec(pde); 327 return rv; 328 } 329 330 static int proc_reg_open(struct inode *inode, struct file *file) 331 { 332 struct proc_dir_entry *pde = PDE(inode); 333 int rv = 0; 334 int (*open)(struct inode *, struct file *); 335 336 spin_lock(&pde->pde_unload_lock); 337 if (!pde->proc_fops) { 338 spin_unlock(&pde->pde_unload_lock); 339 return rv; 340 } 341 pde->pde_users++; 342 open = pde->proc_fops->open; 343 spin_unlock(&pde->pde_unload_lock); 344 345 if (open) 346 rv = open(inode, file); 347 348 pde_users_dec(pde); 349 return rv; 350 } 351 352 static int proc_reg_release(struct inode *inode, struct file *file) 353 { 354 struct proc_dir_entry *pde = PDE(inode); 355 int rv = 0; 356 int (*release)(struct inode *, struct file *); 357 358 spin_lock(&pde->pde_unload_lock); 359 if (!pde->proc_fops) { 360 spin_unlock(&pde->pde_unload_lock); 361 return rv; 362 } 363 pde->pde_users++; 364 release = pde->proc_fops->release; 365 spin_unlock(&pde->pde_unload_lock); 366 367 if (release) 368 rv = release(inode, file); 369 370 pde_users_dec(pde); 371 return rv; 372 } 373 374 static const struct file_operations proc_reg_file_ops = { 375 .llseek = proc_reg_llseek, 376 .read = proc_reg_read, 377 .write = proc_reg_write, 378 .poll = proc_reg_poll, 379 .unlocked_ioctl = proc_reg_unlocked_ioctl, 380 #ifdef CONFIG_COMPAT 381 .compat_ioctl = proc_reg_compat_ioctl, 382 #endif 383 .mmap = proc_reg_mmap, 384 .open = proc_reg_open, 385 .release = proc_reg_release, 386 }; 387 388 #ifdef CONFIG_COMPAT 389 static const struct file_operations proc_reg_file_ops_no_compat = { 390 .llseek = proc_reg_llseek, 391 .read = proc_reg_read, 392 .write = proc_reg_write, 393 .poll = proc_reg_poll, 394 .unlocked_ioctl = proc_reg_unlocked_ioctl, 395 .mmap = proc_reg_mmap, 396 .open = proc_reg_open, 397 .release = proc_reg_release, 398 }; 399 #endif 400 401 struct inode *proc_get_inode(struct super_block *sb, unsigned int ino, 402 struct proc_dir_entry *de) 403 { 404 struct inode * inode; 405 406 if (de != NULL && !try_module_get(de->owner)) 407 goto out_mod; 408 409 inode = iget(sb, ino); 410 if (!inode) 411 goto out_ino; 412 413 PROC_I(inode)->fd = 0; 414 PROC_I(inode)->pde = de; 415 if (de) { 416 if (de->mode) { 417 inode->i_mode = de->mode; 418 inode->i_uid = de->uid; 419 inode->i_gid = de->gid; 420 } 421 if (de->size) 422 inode->i_size = de->size; 423 if (de->nlink) 424 inode->i_nlink = de->nlink; 425 if (de->proc_iops) 426 inode->i_op = de->proc_iops; 427 if (de->proc_fops) { 428 if (S_ISREG(inode->i_mode)) { 429 #ifdef CONFIG_COMPAT 430 if (!de->proc_fops->compat_ioctl) 431 inode->i_fop = 432 &proc_reg_file_ops_no_compat; 433 else 434 #endif 435 inode->i_fop = &proc_reg_file_ops; 436 } 437 else 438 inode->i_fop = de->proc_fops; 439 } 440 } 441 442 return inode; 443 444 out_ino: 445 if (de != NULL) 446 module_put(de->owner); 447 out_mod: 448 return NULL; 449 } 450 451 int proc_fill_super(struct super_block *s) 452 { 453 struct inode * root_inode; 454 455 s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC; 456 s->s_blocksize = 1024; 457 s->s_blocksize_bits = 10; 458 s->s_magic = PROC_SUPER_MAGIC; 459 s->s_op = &proc_sops; 460 s->s_time_gran = 1; 461 462 de_get(&proc_root); 463 root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root); 464 if (!root_inode) 465 goto out_no_root; 466 root_inode->i_uid = 0; 467 root_inode->i_gid = 0; 468 s->s_root = d_alloc_root(root_inode); 469 if (!s->s_root) 470 goto out_no_root; 471 return 0; 472 473 out_no_root: 474 printk("proc_read_super: get root inode failed\n"); 475 iput(root_inode); 476 de_put(&proc_root); 477 return -ENOMEM; 478 } 479 MODULE_LICENSE("GPL"); 480