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 static inline bool pde_has_proc_lseek(const struct proc_dir_entry *pde) 102 { 103 return pde->flags & PROC_ENTRY_proc_lseek; 104 } 105 106 extern struct kmem_cache *proc_dir_entry_cache; 107 void pde_free(struct proc_dir_entry *pde); 108 109 union proc_op { 110 int (*proc_get_link)(struct dentry *, struct path *); 111 int (*proc_show)(struct seq_file *m, 112 struct pid_namespace *ns, struct pid *pid, 113 struct task_struct *task); 114 int lsmid; 115 }; 116 117 struct proc_inode { 118 struct pid *pid; 119 unsigned int fd; 120 union proc_op op; 121 struct proc_dir_entry *pde; 122 struct ctl_table_header *sysctl; 123 const struct ctl_table *sysctl_entry; 124 struct hlist_node sibling_inodes; 125 const struct proc_ns_operations *ns_ops; 126 struct inode vfs_inode; 127 } __randomize_layout; 128 129 /* 130 * General functions 131 */ 132 static inline struct proc_inode *PROC_I(const struct inode *inode) 133 { 134 return container_of(inode, struct proc_inode, vfs_inode); 135 } 136 137 static inline struct proc_dir_entry *PDE(const struct inode *inode) 138 { 139 return PROC_I(inode)->pde; 140 } 141 142 static inline struct pid *proc_pid(const struct inode *inode) 143 { 144 return PROC_I(inode)->pid; 145 } 146 147 static inline struct task_struct *get_proc_task(const struct inode *inode) 148 { 149 return get_pid_task(proc_pid(inode), PIDTYPE_PID); 150 } 151 152 void task_dump_owner(struct task_struct *task, umode_t mode, 153 kuid_t *ruid, kgid_t *rgid); 154 155 unsigned name_to_int(const struct qstr *qstr); 156 /* 157 * Offset of the first process in the /proc root directory.. 158 */ 159 #define FIRST_PROCESS_ENTRY 256 160 161 /* Worst case buffer size needed for holding an integer. */ 162 #define PROC_NUMBUF 13 163 164 #ifdef CONFIG_PAGE_MAPCOUNT 165 /** 166 * folio_precise_page_mapcount() - Number of mappings of this folio page. 167 * @folio: The folio. 168 * @page: The page. 169 * 170 * The number of present user page table entries that reference this page 171 * as tracked via the RMAP: either referenced directly (PTE) or as part of 172 * a larger area that covers this page (e.g., PMD). 173 * 174 * Use this function only for the calculation of existing statistics 175 * (USS, PSS, mapcount_max) and for debugging purposes (/proc/kpagecount). 176 * 177 * Do not add new users. 178 * 179 * Returns: The number of mappings of this folio page. 0 for 180 * folios that are not mapped to user space or are not tracked via the RMAP 181 * (e.g., shared zeropage). 182 */ 183 static inline int folio_precise_page_mapcount(struct folio *folio, 184 struct page *page) 185 { 186 int mapcount = atomic_read(&page->_mapcount) + 1; 187 188 if (page_mapcount_is_type(mapcount)) 189 mapcount = 0; 190 if (folio_test_large(folio)) 191 mapcount += folio_entire_mapcount(folio); 192 193 return mapcount; 194 } 195 #else /* !CONFIG_PAGE_MAPCOUNT */ 196 static inline int folio_precise_page_mapcount(struct folio *folio, 197 struct page *page) 198 { 199 BUILD_BUG(); 200 } 201 #endif /* CONFIG_PAGE_MAPCOUNT */ 202 203 /** 204 * folio_average_page_mapcount() - Average number of mappings per page in this 205 * folio 206 * @folio: The folio. 207 * 208 * The average number of user page table entries that reference each page in 209 * this folio as tracked via the RMAP: either referenced directly (PTE) or 210 * as part of a larger area that covers this page (e.g., PMD). 211 * 212 * The average is calculated by rounding to the nearest integer; however, 213 * to avoid duplicated code in current callers, the average is at least 214 * 1 if any page of the folio is mapped. 215 * 216 * Returns: The average number of mappings per page in this folio. 217 */ 218 static inline int folio_average_page_mapcount(struct folio *folio) 219 { 220 int mapcount, entire_mapcount, avg; 221 222 if (!folio_test_large(folio)) 223 return atomic_read(&folio->_mapcount) + 1; 224 225 mapcount = folio_large_mapcount(folio); 226 if (unlikely(mapcount <= 0)) 227 return 0; 228 entire_mapcount = folio_entire_mapcount(folio); 229 if (mapcount <= entire_mapcount) 230 return entire_mapcount; 231 mapcount -= entire_mapcount; 232 233 /* Round to closest integer ... */ 234 avg = ((unsigned int)mapcount + folio_large_nr_pages(folio) / 2) >> folio_large_order(folio); 235 /* ... but return at least 1. */ 236 return max_t(int, avg + entire_mapcount, 1); 237 } 238 /* 239 * array.c 240 */ 241 extern const struct file_operations proc_tid_children_operations; 242 243 extern void proc_task_name(struct seq_file *m, struct task_struct *p, 244 bool escape); 245 extern int proc_tid_stat(struct seq_file *, struct pid_namespace *, 246 struct pid *, struct task_struct *); 247 extern int proc_tgid_stat(struct seq_file *, struct pid_namespace *, 248 struct pid *, struct task_struct *); 249 extern int proc_pid_status(struct seq_file *, struct pid_namespace *, 250 struct pid *, struct task_struct *); 251 extern int proc_pid_statm(struct seq_file *, struct pid_namespace *, 252 struct pid *, struct task_struct *); 253 254 /* 255 * base.c 256 */ 257 extern const struct dentry_operations pid_dentry_operations; 258 extern int pid_getattr(struct mnt_idmap *, const struct path *, 259 struct kstat *, u32, unsigned int); 260 extern int proc_setattr(struct mnt_idmap *, struct dentry *, 261 struct iattr *); 262 extern void proc_pid_evict_inode(struct proc_inode *); 263 extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t); 264 extern void pid_update_inode(struct task_struct *, struct inode *); 265 extern int pid_delete_dentry(const struct dentry *); 266 extern int proc_pid_readdir(struct file *, struct dir_context *); 267 struct dentry *proc_pid_lookup(struct dentry *, unsigned int); 268 extern loff_t mem_lseek(struct file *, loff_t, int); 269 270 /* Lookups */ 271 typedef struct dentry *instantiate_t(struct dentry *, 272 struct task_struct *, const void *); 273 bool proc_fill_cache(struct file *, struct dir_context *, const char *, unsigned int, 274 instantiate_t, struct task_struct *, const void *); 275 276 /* 277 * generic.c 278 */ 279 struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode, 280 struct proc_dir_entry **parent, void *data); 281 struct proc_dir_entry *proc_register(struct proc_dir_entry *dir, 282 struct proc_dir_entry *dp); 283 extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int); 284 struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *); 285 extern int proc_readdir(struct file *, struct dir_context *); 286 int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *); 287 288 static inline void pde_get(struct proc_dir_entry *pde) 289 { 290 refcount_inc(&pde->refcnt); 291 } 292 extern void pde_put(struct proc_dir_entry *); 293 294 static inline bool is_empty_pde(const struct proc_dir_entry *pde) 295 { 296 return S_ISDIR(pde->mode) && !pde->proc_iops; 297 } 298 extern ssize_t proc_simple_write(struct file *, const char __user *, size_t, loff_t *); 299 300 /* 301 * inode.c 302 */ 303 struct pde_opener { 304 struct list_head lh; 305 struct file *file; 306 bool closing; 307 struct completion *c; 308 } __randomize_layout; 309 extern const struct inode_operations proc_link_inode_operations; 310 extern const struct inode_operations proc_pid_link_inode_operations; 311 extern const struct super_operations proc_sops; 312 313 void proc_init_kmemcache(void); 314 void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock); 315 void set_proc_pid_nlink(void); 316 extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *); 317 extern void proc_entry_rundown(struct proc_dir_entry *); 318 319 /* 320 * proc_namespaces.c 321 */ 322 extern const struct inode_operations proc_ns_dir_inode_operations; 323 extern const struct file_operations proc_ns_dir_operations; 324 325 /* 326 * proc_net.c 327 */ 328 extern const struct file_operations proc_net_operations; 329 extern const struct inode_operations proc_net_inode_operations; 330 331 #ifdef CONFIG_NET 332 extern int proc_net_init(void); 333 #else 334 static inline int proc_net_init(void) { return 0; } 335 #endif 336 337 /* 338 * proc_self.c 339 */ 340 extern int proc_setup_self(struct super_block *); 341 342 /* 343 * proc_thread_self.c 344 */ 345 extern int proc_setup_thread_self(struct super_block *); 346 extern void proc_thread_self_init(void); 347 348 /* 349 * proc_sysctl.c 350 */ 351 #ifdef CONFIG_PROC_SYSCTL 352 extern int proc_sys_init(void); 353 extern void proc_sys_evict_inode(struct inode *inode, 354 struct ctl_table_header *head); 355 #else 356 static inline void proc_sys_init(void) { } 357 static inline void proc_sys_evict_inode(struct inode *inode, 358 struct ctl_table_header *head) { } 359 #endif 360 361 /* 362 * proc_tty.c 363 */ 364 #ifdef CONFIG_TTY 365 extern void proc_tty_init(void); 366 #else 367 static inline void proc_tty_init(void) {} 368 #endif 369 370 /* 371 * root.c 372 */ 373 extern struct proc_dir_entry proc_root; 374 375 extern void proc_self_init(void); 376 377 /* 378 * task_[no]mmu.c 379 */ 380 struct mem_size_stats; 381 struct proc_maps_private { 382 struct inode *inode; 383 struct task_struct *task; 384 struct mm_struct *mm; 385 struct vma_iterator iter; 386 loff_t last_pos; 387 #ifdef CONFIG_PER_VMA_LOCK 388 bool mmap_locked; 389 struct vm_area_struct *locked_vma; 390 #endif 391 #ifdef CONFIG_NUMA 392 struct mempolicy *task_mempolicy; 393 #endif 394 } __randomize_layout; 395 396 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode); 397 398 extern const struct file_operations proc_pid_maps_operations; 399 extern const struct file_operations proc_pid_numa_maps_operations; 400 extern const struct file_operations proc_pid_smaps_operations; 401 extern const struct file_operations proc_pid_smaps_rollup_operations; 402 extern const struct file_operations proc_clear_refs_operations; 403 extern const struct file_operations proc_pagemap_operations; 404 405 extern unsigned long task_vsize(struct mm_struct *); 406 extern unsigned long task_statm(struct mm_struct *, 407 unsigned long *, unsigned long *, 408 unsigned long *, unsigned long *); 409 extern void task_mem(struct seq_file *, struct mm_struct *); 410 411 extern const struct dentry_operations proc_net_dentry_ops; 412 static inline void pde_force_lookup(struct proc_dir_entry *pde) 413 { 414 /* /proc/net/ entries can be changed under us by setns(CLONE_NEWNET) */ 415 pde->flags |= PROC_ENTRY_FORCE_LOOKUP; 416 } 417 418 /* 419 * Add a new procfs dentry that can't serve as a mountpoint. That should 420 * encompass anything that is ephemeral and can just disappear while the 421 * process is still around. 422 */ 423 static inline struct dentry *proc_splice_unmountable(struct inode *inode, 424 struct dentry *dentry, const struct dentry_operations *d_ops) 425 { 426 dont_mount(dentry); 427 return d_splice_alias_ops(inode, dentry, d_ops); 428 } 429