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