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 static inline void pde_make_permanent(struct proc_dir_entry *pde) 83 { 84 pde->flags |= PROC_ENTRY_PERMANENT; 85 } 86 87 static inline bool pde_has_proc_read_iter(const struct proc_dir_entry *pde) 88 { 89 return pde->flags & PROC_ENTRY_proc_read_iter; 90 } 91 92 static inline bool pde_has_proc_compat_ioctl(const struct proc_dir_entry *pde) 93 { 94 #ifdef CONFIG_COMPAT 95 return pde->flags & PROC_ENTRY_proc_compat_ioctl; 96 #else 97 return false; 98 #endif 99 } 100 101 extern struct kmem_cache *proc_dir_entry_cache; 102 void pde_free(struct proc_dir_entry *pde); 103 104 union proc_op { 105 int (*proc_get_link)(struct dentry *, struct path *); 106 int (*proc_show)(struct seq_file *m, 107 struct pid_namespace *ns, struct pid *pid, 108 struct task_struct *task); 109 int lsmid; 110 }; 111 112 struct proc_inode { 113 struct pid *pid; 114 unsigned int fd; 115 union proc_op op; 116 struct proc_dir_entry *pde; 117 struct ctl_table_header *sysctl; 118 const struct ctl_table *sysctl_entry; 119 struct hlist_node sibling_inodes; 120 const struct proc_ns_operations *ns_ops; 121 struct inode vfs_inode; 122 } __randomize_layout; 123 124 /* 125 * General functions 126 */ 127 static inline struct proc_inode *PROC_I(const struct inode *inode) 128 { 129 return container_of(inode, struct proc_inode, vfs_inode); 130 } 131 132 static inline struct proc_dir_entry *PDE(const struct inode *inode) 133 { 134 return PROC_I(inode)->pde; 135 } 136 137 static inline struct pid *proc_pid(const struct inode *inode) 138 { 139 return PROC_I(inode)->pid; 140 } 141 142 static inline struct task_struct *get_proc_task(const struct inode *inode) 143 { 144 return get_pid_task(proc_pid(inode), PIDTYPE_PID); 145 } 146 147 void task_dump_owner(struct task_struct *task, umode_t mode, 148 kuid_t *ruid, kgid_t *rgid); 149 150 unsigned name_to_int(const struct qstr *qstr); 151 /* 152 * Offset of the first process in the /proc root directory.. 153 */ 154 #define FIRST_PROCESS_ENTRY 256 155 156 /* Worst case buffer size needed for holding an integer. */ 157 #define PROC_NUMBUF 13 158 159 #ifdef CONFIG_PAGE_MAPCOUNT 160 /** 161 * folio_precise_page_mapcount() - Number of mappings of this folio page. 162 * @folio: The folio. 163 * @page: The page. 164 * 165 * The number of present user page table entries that reference this page 166 * as tracked via the RMAP: either referenced directly (PTE) or as part of 167 * a larger area that covers this page (e.g., PMD). 168 * 169 * Use this function only for the calculation of existing statistics 170 * (USS, PSS, mapcount_max) and for debugging purposes (/proc/kpagecount). 171 * 172 * Do not add new users. 173 * 174 * Returns: The number of mappings of this folio page. 0 for 175 * folios that are not mapped to user space or are not tracked via the RMAP 176 * (e.g., shared zeropage). 177 */ 178 static inline int folio_precise_page_mapcount(struct folio *folio, 179 struct page *page) 180 { 181 int mapcount = atomic_read(&page->_mapcount) + 1; 182 183 if (page_mapcount_is_type(mapcount)) 184 mapcount = 0; 185 if (folio_test_large(folio)) 186 mapcount += folio_entire_mapcount(folio); 187 188 return mapcount; 189 } 190 #else /* !CONFIG_PAGE_MAPCOUNT */ 191 static inline int folio_precise_page_mapcount(struct folio *folio, 192 struct page *page) 193 { 194 BUILD_BUG(); 195 } 196 #endif /* CONFIG_PAGE_MAPCOUNT */ 197 198 /** 199 * folio_average_page_mapcount() - Average number of mappings per page in this 200 * folio 201 * @folio: The folio. 202 * 203 * The average number of user page table entries that reference each page in 204 * this folio as tracked via the RMAP: either referenced directly (PTE) or 205 * as part of a larger area that covers this page (e.g., PMD). 206 * 207 * The average is calculated by rounding to the nearest integer; however, 208 * to avoid duplicated code in current callers, the average is at least 209 * 1 if any page of the folio is mapped. 210 * 211 * Returns: The average number of mappings per page in this folio. 212 */ 213 static inline int folio_average_page_mapcount(struct folio *folio) 214 { 215 int mapcount, entire_mapcount, avg; 216 217 if (!folio_test_large(folio)) 218 return atomic_read(&folio->_mapcount) + 1; 219 220 mapcount = folio_large_mapcount(folio); 221 if (unlikely(mapcount <= 0)) 222 return 0; 223 entire_mapcount = folio_entire_mapcount(folio); 224 if (mapcount <= entire_mapcount) 225 return entire_mapcount; 226 mapcount -= entire_mapcount; 227 228 /* Round to closest integer ... */ 229 avg = ((unsigned int)mapcount + folio_large_nr_pages(folio) / 2) >> folio_large_order(folio); 230 /* ... but return at least 1. */ 231 return max_t(int, avg + entire_mapcount, 1); 232 } 233 /* 234 * array.c 235 */ 236 extern const struct file_operations proc_tid_children_operations; 237 238 extern void proc_task_name(struct seq_file *m, struct task_struct *p, 239 bool escape); 240 extern int proc_tid_stat(struct seq_file *, struct pid_namespace *, 241 struct pid *, struct task_struct *); 242 extern int proc_tgid_stat(struct seq_file *, struct pid_namespace *, 243 struct pid *, struct task_struct *); 244 extern int proc_pid_status(struct seq_file *, struct pid_namespace *, 245 struct pid *, struct task_struct *); 246 extern int proc_pid_statm(struct seq_file *, struct pid_namespace *, 247 struct pid *, struct task_struct *); 248 249 /* 250 * base.c 251 */ 252 extern const struct dentry_operations pid_dentry_operations; 253 extern int pid_getattr(struct mnt_idmap *, const struct path *, 254 struct kstat *, u32, unsigned int); 255 extern int proc_setattr(struct mnt_idmap *, struct dentry *, 256 struct iattr *); 257 extern void proc_pid_evict_inode(struct proc_inode *); 258 extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t); 259 extern void pid_update_inode(struct task_struct *, struct inode *); 260 extern int pid_delete_dentry(const struct dentry *); 261 extern int proc_pid_readdir(struct file *, struct dir_context *); 262 struct dentry *proc_pid_lookup(struct dentry *, unsigned int); 263 extern loff_t mem_lseek(struct file *, loff_t, int); 264 265 /* Lookups */ 266 typedef struct dentry *instantiate_t(struct dentry *, 267 struct task_struct *, const void *); 268 bool proc_fill_cache(struct file *, struct dir_context *, const char *, unsigned int, 269 instantiate_t, struct task_struct *, const void *); 270 271 /* 272 * generic.c 273 */ 274 struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode, 275 struct proc_dir_entry **parent, void *data); 276 struct proc_dir_entry *proc_register(struct proc_dir_entry *dir, 277 struct proc_dir_entry *dp); 278 extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int); 279 struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *); 280 extern int proc_readdir(struct file *, struct dir_context *); 281 int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *); 282 283 static inline void pde_get(struct proc_dir_entry *pde) 284 { 285 refcount_inc(&pde->refcnt); 286 } 287 extern void pde_put(struct proc_dir_entry *); 288 289 static inline bool is_empty_pde(const struct proc_dir_entry *pde) 290 { 291 return S_ISDIR(pde->mode) && !pde->proc_iops; 292 } 293 extern ssize_t proc_simple_write(struct file *, const char __user *, size_t, loff_t *); 294 295 /* 296 * inode.c 297 */ 298 struct pde_opener { 299 struct list_head lh; 300 struct file *file; 301 bool closing; 302 struct completion *c; 303 } __randomize_layout; 304 extern const struct inode_operations proc_link_inode_operations; 305 extern const struct inode_operations proc_pid_link_inode_operations; 306 extern const struct super_operations proc_sops; 307 308 void proc_init_kmemcache(void); 309 void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock); 310 void set_proc_pid_nlink(void); 311 extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *); 312 extern void proc_entry_rundown(struct proc_dir_entry *); 313 314 /* 315 * proc_namespaces.c 316 */ 317 extern const struct inode_operations proc_ns_dir_inode_operations; 318 extern const struct file_operations proc_ns_dir_operations; 319 320 /* 321 * proc_net.c 322 */ 323 extern const struct file_operations proc_net_operations; 324 extern const struct inode_operations proc_net_inode_operations; 325 326 #ifdef CONFIG_NET 327 extern int proc_net_init(void); 328 #else 329 static inline int proc_net_init(void) { return 0; } 330 #endif 331 332 /* 333 * proc_self.c 334 */ 335 extern int proc_setup_self(struct super_block *); 336 337 /* 338 * proc_thread_self.c 339 */ 340 extern int proc_setup_thread_self(struct super_block *); 341 extern void proc_thread_self_init(void); 342 343 /* 344 * proc_sysctl.c 345 */ 346 #ifdef CONFIG_PROC_SYSCTL 347 extern int proc_sys_init(void); 348 extern void proc_sys_evict_inode(struct inode *inode, 349 struct ctl_table_header *head); 350 #else 351 static inline void proc_sys_init(void) { } 352 static inline void proc_sys_evict_inode(struct inode *inode, 353 struct ctl_table_header *head) { } 354 #endif 355 356 /* 357 * proc_tty.c 358 */ 359 #ifdef CONFIG_TTY 360 extern void proc_tty_init(void); 361 #else 362 static inline void proc_tty_init(void) {} 363 #endif 364 365 /* 366 * root.c 367 */ 368 extern struct proc_dir_entry proc_root; 369 370 extern void proc_self_init(void); 371 372 /* 373 * task_[no]mmu.c 374 */ 375 struct mem_size_stats; 376 struct proc_maps_private { 377 struct inode *inode; 378 struct task_struct *task; 379 struct mm_struct *mm; 380 struct vma_iterator iter; 381 #ifdef CONFIG_NUMA 382 struct mempolicy *task_mempolicy; 383 #endif 384 } __randomize_layout; 385 386 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode); 387 388 extern const struct file_operations proc_pid_maps_operations; 389 extern const struct file_operations proc_pid_numa_maps_operations; 390 extern const struct file_operations proc_pid_smaps_operations; 391 extern const struct file_operations proc_pid_smaps_rollup_operations; 392 extern const struct file_operations proc_clear_refs_operations; 393 extern const struct file_operations proc_pagemap_operations; 394 395 extern unsigned long task_vsize(struct mm_struct *); 396 extern unsigned long task_statm(struct mm_struct *, 397 unsigned long *, unsigned long *, 398 unsigned long *, unsigned long *); 399 extern void task_mem(struct seq_file *, struct mm_struct *); 400 401 extern const struct dentry_operations proc_net_dentry_ops; 402 static inline void pde_force_lookup(struct proc_dir_entry *pde) 403 { 404 /* /proc/net/ entries can be changed under us by setns(CLONE_NEWNET) */ 405 pde->flags |= PROC_ENTRY_FORCE_LOOKUP; 406 } 407 408 /* 409 * Add a new procfs dentry that can't serve as a mountpoint. That should 410 * encompass anything that is ephemeral and can just disappear while the 411 * process is still around. 412 */ 413 static inline struct dentry *proc_splice_unmountable(struct inode *inode, 414 struct dentry *dentry, const struct dentry_operations *d_ops) 415 { 416 dont_mount(dentry); 417 return d_splice_alias_ops(inode, dentry, d_ops); 418 } 419