1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* Internal procfs definitions 3 * 4 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #include <linux/proc_fs.h> 9 #include <linux/proc_ns.h> 10 #include <linux/refcount.h> 11 #include <linux/spinlock.h> 12 #include <linux/atomic.h> 13 #include <linux/binfmts.h> 14 #include <linux/sched/coredump.h> 15 #include <linux/sched/task.h> 16 #include <linux/mm.h> 17 18 struct ctl_table_header; 19 struct mempolicy; 20 21 /* 22 * This is not completely implemented yet. The idea is to 23 * create an in-memory tree (like the actual /proc filesystem 24 * tree) of these proc_dir_entries, so that we can dynamically 25 * add new files to /proc. 26 * 27 * parent/subdir are used for the directory structure (every /proc file has a 28 * parent, but "subdir" is empty for all non-directory entries). 29 * subdir_node is used to build the rb tree "subdir" of the parent. 30 */ 31 struct proc_dir_entry { 32 /* 33 * number of callers into module in progress; 34 * negative -> it's going away RSN 35 */ 36 atomic_t in_use; 37 refcount_t refcnt; 38 struct list_head pde_openers; /* who did ->open, but not ->release */ 39 /* protects ->pde_openers and all struct pde_opener instances */ 40 spinlock_t pde_unload_lock; 41 struct completion *pde_unload_completion; 42 const struct inode_operations *proc_iops; 43 union { 44 const struct proc_ops *proc_ops; 45 const struct file_operations *proc_dir_ops; 46 }; 47 union { 48 const struct seq_operations *seq_ops; 49 int (*single_show)(struct seq_file *, void *); 50 }; 51 proc_write_t write; 52 void *data; 53 unsigned int state_size; 54 unsigned int low_ino; 55 nlink_t nlink; 56 kuid_t uid; 57 kgid_t gid; 58 loff_t size; 59 struct proc_dir_entry *parent; 60 struct rb_root subdir; 61 struct rb_node subdir_node; 62 char *name; 63 umode_t mode; 64 u8 flags; 65 u8 namelen; 66 char inline_name[]; 67 } __randomize_layout; 68 69 #define SIZEOF_PDE ( \ 70 sizeof(struct proc_dir_entry) < 128 ? 128 : \ 71 sizeof(struct proc_dir_entry) < 192 ? 192 : \ 72 sizeof(struct proc_dir_entry) < 256 ? 256 : \ 73 sizeof(struct proc_dir_entry) < 512 ? 512 : \ 74 0) 75 #define SIZEOF_PDE_INLINE_NAME (SIZEOF_PDE - sizeof(struct proc_dir_entry)) 76 77 static inline bool pde_is_permanent(const struct proc_dir_entry *pde) 78 { 79 return pde->flags & PROC_ENTRY_PERMANENT; 80 } 81 82 /* This is for builtin code, not even for modules which are compiled in. */ 83 static inline void pde_make_permanent(struct proc_dir_entry *pde) 84 { 85 /* Ensure magic flag does something. */ 86 static_assert(PROC_ENTRY_PERMANENT != 0); 87 pde->flags |= PROC_ENTRY_PERMANENT; 88 } 89 90 static inline bool pde_has_proc_read_iter(const struct proc_dir_entry *pde) 91 { 92 return pde->flags & PROC_ENTRY_proc_read_iter; 93 } 94 95 static inline bool pde_has_proc_compat_ioctl(const struct proc_dir_entry *pde) 96 { 97 #ifdef CONFIG_COMPAT 98 return pde->flags & PROC_ENTRY_proc_compat_ioctl; 99 #else 100 return false; 101 #endif 102 } 103 104 static inline bool pde_has_proc_lseek(const struct proc_dir_entry *pde) 105 { 106 return pde->flags & PROC_ENTRY_proc_lseek; 107 } 108 109 extern struct kmem_cache *proc_dir_entry_cache; 110 void pde_free(struct proc_dir_entry *pde); 111 112 union proc_op { 113 int (*proc_get_link)(struct dentry *, struct path *, struct task_struct *); 114 int (*proc_show)(struct seq_file *m, 115 struct pid_namespace *ns, struct pid *pid, 116 struct task_struct *task); 117 int lsmid; 118 }; 119 120 struct proc_inode { 121 struct pid *pid; 122 unsigned int fd; 123 union proc_op op; 124 struct proc_dir_entry *pde; 125 struct ctl_table_header *sysctl; 126 const struct ctl_table *sysctl_entry; 127 struct hlist_node sibling_inodes; 128 const struct proc_ns_operations *ns_ops; 129 struct inode vfs_inode; 130 } __randomize_layout; 131 132 /* 133 * General functions 134 */ 135 static inline struct proc_inode *PROC_I(const struct inode *inode) 136 { 137 return container_of(inode, struct proc_inode, vfs_inode); 138 } 139 140 static inline struct proc_dir_entry *PDE(const struct inode *inode) 141 { 142 return PROC_I(inode)->pde; 143 } 144 145 static inline struct pid *proc_pid(const struct inode *inode) 146 { 147 return PROC_I(inode)->pid; 148 } 149 150 static inline struct task_struct *get_proc_task(const struct inode *inode) 151 { 152 return get_pid_task(proc_pid(inode), PIDTYPE_PID); 153 } 154 155 void task_dump_owner(struct task_struct *task, umode_t mode, 156 kuid_t *ruid, kgid_t *rgid); 157 158 unsigned name_to_int(const struct qstr *qstr); 159 /* 160 * Offset of the first process in the /proc root directory.. 161 */ 162 #define FIRST_PROCESS_ENTRY 256 163 164 /* Worst case buffer size needed for holding an integer. */ 165 #define PROC_NUMBUF 13 166 167 #ifdef CONFIG_PAGE_MAPCOUNT 168 /** 169 * folio_precise_page_mapcount() - Number of mappings of this folio page. 170 * @folio: The folio. 171 * @page: The page. 172 * 173 * The number of present user page table entries that reference this page 174 * as tracked via the RMAP: either referenced directly (PTE) or as part of 175 * a larger area that covers this page (e.g., PMD). 176 * 177 * Use this function only for the calculation of existing statistics 178 * (USS, PSS, mapcount_max) and for debugging purposes (/proc/kpagecount). 179 * 180 * Do not add new users. 181 * 182 * Returns: The number of mappings of this folio page. 0 for 183 * folios that are not mapped to user space or are not tracked via the RMAP 184 * (e.g., shared zeropage). 185 */ 186 static inline int folio_precise_page_mapcount(struct folio *folio, 187 struct page *page) 188 { 189 int mapcount = atomic_read(&page->_mapcount) + 1; 190 191 if (page_mapcount_is_type(mapcount)) 192 mapcount = 0; 193 if (folio_test_large(folio)) 194 mapcount += folio_entire_mapcount(folio); 195 196 return mapcount; 197 } 198 #else /* !CONFIG_PAGE_MAPCOUNT */ 199 static inline int folio_precise_page_mapcount(struct folio *folio, 200 struct page *page) 201 { 202 BUILD_BUG(); 203 } 204 #endif /* CONFIG_PAGE_MAPCOUNT */ 205 206 /** 207 * folio_average_page_mapcount() - Average number of mappings per page in this 208 * folio 209 * @folio: The folio. 210 * 211 * The average number of user page table entries that reference each page in 212 * this folio as tracked via the RMAP: either referenced directly (PTE) or 213 * as part of a larger area that covers this page (e.g., PMD). 214 * 215 * The average is calculated by rounding to the nearest integer; however, 216 * to avoid duplicated code in current callers, the average is at least 217 * 1 if any page of the folio is mapped. 218 * 219 * Returns: The average number of mappings per page in this folio. 220 */ 221 static inline int folio_average_page_mapcount(struct folio *folio) 222 { 223 int mapcount, entire_mapcount, avg; 224 225 if (!folio_test_large(folio)) 226 return atomic_read(&folio->_mapcount) + 1; 227 228 mapcount = folio_large_mapcount(folio); 229 if (unlikely(mapcount <= 0)) 230 return 0; 231 entire_mapcount = folio_entire_mapcount(folio); 232 if (mapcount <= entire_mapcount) 233 return entire_mapcount; 234 mapcount -= entire_mapcount; 235 236 /* Round to closest integer ... */ 237 avg = ((unsigned int)mapcount + folio_large_nr_pages(folio) / 2) >> folio_large_order(folio); 238 /* ... but return at least 1. */ 239 return max_t(int, avg + entire_mapcount, 1); 240 } 241 /* 242 * array.c 243 */ 244 extern const struct file_operations proc_tid_children_operations; 245 246 extern void proc_task_name(struct seq_file *m, struct task_struct *p, 247 bool escape); 248 extern int proc_tid_stat(struct seq_file *, struct pid_namespace *, 249 struct pid *, struct task_struct *); 250 extern int proc_tgid_stat(struct seq_file *, struct pid_namespace *, 251 struct pid *, struct task_struct *); 252 extern int proc_pid_status(struct seq_file *, struct pid_namespace *, 253 struct pid *, struct task_struct *); 254 extern int proc_pid_statm(struct seq_file *, struct pid_namespace *, 255 struct pid *, struct task_struct *); 256 257 /* 258 * base.c 259 */ 260 extern const struct dentry_operations pid_dentry_operations; 261 extern int pid_getattr(struct mnt_idmap *, const struct path *, 262 struct kstat *, u32, unsigned int); 263 int proc_nochmod_setattr(struct mnt_idmap *idmap, struct dentry *dentry, 264 struct iattr *attr); 265 extern void proc_pid_evict_inode(struct proc_inode *); 266 extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t); 267 extern void pid_update_inode(struct task_struct *, struct inode *); 268 extern int pid_delete_dentry(const struct dentry *); 269 extern int proc_pid_readdir(struct file *, struct dir_context *); 270 struct dentry *proc_pid_lookup(struct dentry *, unsigned int); 271 extern loff_t mem_lseek(struct file *, loff_t, int); 272 273 /* Lookups */ 274 typedef struct dentry *instantiate_t(struct dentry *, 275 struct task_struct *, const void *); 276 bool proc_fill_cache(struct file *, struct dir_context *, const char *, unsigned int, 277 instantiate_t, struct task_struct *, const void *); 278 279 /* 280 * generic.c 281 */ 282 struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode, 283 struct proc_dir_entry **parent, void *data); 284 struct proc_dir_entry *proc_register(struct proc_dir_entry *dir, 285 struct proc_dir_entry *dp); 286 extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int); 287 struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *); 288 extern int proc_readdir(struct file *, struct dir_context *); 289 int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *); 290 291 static inline void pde_get(struct proc_dir_entry *pde) 292 { 293 refcount_inc(&pde->refcnt); 294 } 295 extern void pde_put(struct proc_dir_entry *); 296 297 static inline bool is_empty_pde(const struct proc_dir_entry *pde) 298 { 299 return S_ISDIR(pde->mode) && !pde->proc_iops; 300 } 301 extern ssize_t proc_simple_write(struct file *, const char __user *, size_t, loff_t *); 302 303 /* 304 * inode.c 305 */ 306 struct pde_opener { 307 struct list_head lh; 308 struct file *file; 309 bool closing; 310 struct completion *c; 311 } __randomize_layout; 312 extern const struct inode_operations proc_link_inode_operations; 313 extern const struct inode_operations proc_pid_link_inode_operations; 314 extern const struct super_operations proc_sops; 315 316 void proc_init_kmemcache(void); 317 void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock); 318 void set_proc_pid_nlink(void); 319 extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *); 320 extern void proc_entry_rundown(struct proc_dir_entry *); 321 322 /* 323 * proc_namespaces.c 324 */ 325 extern const struct inode_operations proc_ns_dir_inode_operations; 326 extern const struct file_operations proc_ns_dir_operations; 327 328 /* 329 * proc_net.c 330 */ 331 extern const struct file_operations proc_net_operations; 332 extern const struct inode_operations proc_net_inode_operations; 333 334 #ifdef CONFIG_NET 335 extern int proc_net_init(void); 336 #else 337 static inline int proc_net_init(void) { return 0; } 338 #endif 339 340 /* 341 * proc_self.c 342 */ 343 extern int proc_setup_self(struct super_block *); 344 345 /* 346 * proc_thread_self.c 347 */ 348 extern int proc_setup_thread_self(struct super_block *); 349 extern void proc_thread_self_init(void); 350 351 /* 352 * proc_sysctl.c 353 */ 354 #ifdef CONFIG_PROC_SYSCTL 355 extern int proc_sys_init(void); 356 extern void proc_sys_evict_inode(struct inode *inode, 357 struct ctl_table_header *head); 358 #else 359 static inline void proc_sys_init(void) { } 360 static inline void proc_sys_evict_inode(struct inode *inode, 361 struct ctl_table_header *head) { } 362 #endif 363 364 /* 365 * proc_tty.c 366 */ 367 #ifdef CONFIG_TTY 368 extern void proc_tty_init(void); 369 #else 370 static inline void proc_tty_init(void) {} 371 #endif 372 373 /* 374 * root.c 375 */ 376 extern struct proc_dir_entry proc_root; 377 378 extern void proc_self_init(void); 379 extern unsigned self_inum, thread_self_inum; 380 381 /* 382 * task_[no]mmu.c 383 */ 384 struct mem_size_stats; 385 386 struct proc_maps_locking_ctx { 387 struct mm_struct *mm; 388 #ifdef CONFIG_PER_VMA_LOCK 389 bool mmap_locked; 390 struct vm_area_struct *locked_vma; 391 #endif 392 }; 393 394 struct proc_maps_private { 395 struct inode *inode; 396 struct task_struct *task; 397 struct vma_iterator iter; 398 loff_t last_pos; 399 struct proc_maps_locking_ctx lock_ctx; 400 #ifdef CONFIG_NUMA 401 struct mempolicy *task_mempolicy; 402 #endif 403 } __randomize_layout; 404 405 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode); 406 407 extern const struct file_operations proc_pid_maps_operations; 408 extern const struct file_operations proc_pid_numa_maps_operations; 409 extern const struct file_operations proc_pid_smaps_operations; 410 extern const struct file_operations proc_pid_smaps_rollup_operations; 411 extern const struct file_operations proc_clear_refs_operations; 412 extern const struct file_operations proc_pagemap_operations; 413 414 extern unsigned long task_vsize(struct mm_struct *); 415 extern unsigned long task_statm(struct mm_struct *, 416 unsigned long *, unsigned long *, 417 unsigned long *, unsigned long *); 418 extern void task_mem(struct seq_file *, struct mm_struct *); 419 420 extern const struct dentry_operations proc_net_dentry_ops; 421 static inline void pde_force_lookup(struct proc_dir_entry *pde) 422 { 423 /* /proc/net/ entries can be changed under us by setns(CLONE_NEWNET) */ 424 pde->flags |= PROC_ENTRY_FORCE_LOOKUP; 425 } 426 427 /* 428 * Add a new procfs dentry that can't serve as a mountpoint. That should 429 * encompass anything that is ephemeral and can just disappear while the 430 * process is still around. 431 */ 432 static inline struct dentry *proc_splice_unmountable(struct inode *inode, 433 struct dentry *dentry, const struct dentry_operations *d_ops) 434 { 435 dont_mount(dentry); 436 return d_splice_alias_ops(inode, dentry, d_ops); 437 } 438