1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_SEQ_FILE_H
3#define _LINUX_SEQ_FILE_H
4
5#include <linux/types.h>
6#include <linux/string.h>
7#include <linux/string_helpers.h>
8#include <linux/bug.h>
9#include <linux/mutex.h>
10#include <linux/nodemask.h>
11#include <linux/fs.h>
12#include <linux/cred.h>
13
14struct seq_operations;
15
16struct seq_file {
17 char *buf;
18 size_t size;
19 size_t from;
20 size_t count;
21 size_t pad_until;
22 loff_t index;
23 loff_t read_pos;
24 struct mutex lock;
25 const struct seq_operations *op;
26 int poll_event;
27 const struct file *file;
28 void *private;
29};
30
31struct seq_operations {
32 void * (*start) (struct seq_file *m, loff_t *pos);
33 void (*stop) (struct seq_file *m, void *v);
34 void * (*next) (struct seq_file *m, void *v, loff_t *pos);
35 int (*show) (struct seq_file *m, void *v);
36};
37
38#define SEQ_SKIP 1
39
40/**
41 * seq_has_overflowed - check if the buffer has overflowed
42 * @m: the seq_file handle
43 *
44 * seq_files have a buffer which may overflow. When this happens a larger
45 * buffer is reallocated and all the data will be printed again.
46 * The overflow state is true when m->count == m->size.
47 *
48 * Returns true if the buffer received more than it can hold.
49 */
50static inline bool seq_has_overflowed(struct seq_file *m)
51{
52 return m->count == m->size;
53}
54
55/**
56 * seq_get_buf - get buffer to write arbitrary data to
57 * @m: the seq_file handle
58 * @bufp: the beginning of the buffer is stored here
59 *
60 * Return the number of bytes available in the buffer, or zero if
61 * there's no space.
62 */
63static inline size_t seq_get_buf(struct seq_file *m, char **bufp)
64{
65 BUG_ON(m->count > m->size);
66 if (m->count < m->size)
67 *bufp = m->buf + m->count;
68 else
69 *bufp = NULL;
70
71 return m->size - m->count;
72}
73
74/**
75 * seq_commit - commit data to the buffer
76 * @m: the seq_file handle
77 * @num: the number of bytes to commit
78 *
79 * Commit @num bytes of data written to a buffer previously acquired
80 * by seq_buf_get. To signal an error condition, or that the data
81 * didn't fit in the available space, pass a negative @num value.
82 */
83static inline void seq_commit(struct seq_file *m, int num)
84{
85 if (num < 0) {
86 m->count = m->size;
87 } else {
88 BUG_ON(m->count + num > m->size);
89 m->count += num;
90 }
91}
92
93/**
94 * seq_setwidth - set padding width
95 * @m: the seq_file handle
96 * @size: the max number of bytes to pad.
97 *
98 * Call seq_setwidth() for setting max width, then call seq_printf() etc. and
99 * finally call seq_pad() to pad the remaining bytes.
100 */
101static inline void seq_setwidth(struct seq_file *m, size_t size)
102{
103 m->pad_until = m->count + size;
104}
105void seq_pad(struct seq_file *m, char c);
106
107char *mangle_path(char *s, const char *p, const char *esc);
108int seq_open(struct file *, const struct seq_operations *);
109ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);
110ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter);
111loff_t seq_lseek(struct file *, loff_t, int);
112int seq_release(struct inode *, struct file *);
113int seq_write(struct seq_file *seq, const void *data, size_t len);
114
115__printf(2, 0)
116void seq_vprintf(struct seq_file *m, const char *fmt, va_list args);
117__printf(2, 3)
118void seq_printf(struct seq_file *m, const char *fmt, ...);
119void seq_putc(struct seq_file *m, char c);
120void __seq_puts(struct seq_file *m, const char *s);
121
122static __always_inline void seq_puts(struct seq_file *m, const char *s)
123{
124 if (!__builtin_constant_p(*s))
125 __seq_puts(m, s);
126 else if (s[0] && !s[1])
127 seq_putc(m, c: s[0]);
128 else
129 seq_write(seq: m, data: s, len: __builtin_strlen(s));
130}
131
132void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
133 unsigned long long num, unsigned int width);
134void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
135 unsigned long long num);
136void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num);
137void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
138 unsigned long long v, unsigned int width);
139
140void seq_escape_mem(struct seq_file *m, const char *src, size_t len,
141 unsigned int flags, const char *esc);
142
143static inline void seq_escape_str(struct seq_file *m, const char *src,
144 unsigned int flags, const char *esc)
145{
146 seq_escape_mem(m, src, len: strlen(src), flags, esc);
147}
148
149/**
150 * seq_escape - print string into buffer, escaping some characters
151 * @m: target buffer
152 * @s: NULL-terminated string
153 * @esc: set of characters that need escaping
154 *
155 * Puts string into buffer, replacing each occurrence of character from
156 * @esc with usual octal escape.
157 *
158 * Use seq_has_overflowed() to check for errors.
159 */
160static inline void seq_escape(struct seq_file *m, const char *s, const char *esc)
161{
162 seq_escape_str(m, src: s, ESCAPE_OCTAL, esc);
163}
164
165void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
166 int rowsize, int groupsize, const void *buf, size_t len,
167 bool ascii);
168
169int seq_path(struct seq_file *, const struct path *, const char *);
170int seq_file_path(struct seq_file *, struct file *, const char *);
171int seq_dentry(struct seq_file *, struct dentry *, const char *);
172int seq_path_root(struct seq_file *m, const struct path *path,
173 const struct path *root, const char *esc);
174
175void *single_start(struct seq_file *, loff_t *);
176int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
177int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
178int single_release(struct inode *, struct file *);
179void *__seq_open_private(struct file *, const struct seq_operations *, int);
180int seq_open_private(struct file *, const struct seq_operations *, int);
181int seq_release_private(struct inode *, struct file *);
182
183#ifdef CONFIG_BINARY_PRINTF
184__printf(2, 0)
185void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary);
186#endif
187
188#define DEFINE_SEQ_ATTRIBUTE(__name) \
189static int __name ## _open(struct inode *inode, struct file *file) \
190{ \
191 int ret = seq_open(file, &__name ## _sops); \
192 if (!ret && inode->i_private) { \
193 struct seq_file *seq_f = file->private_data; \
194 seq_f->private = inode->i_private; \
195 } \
196 return ret; \
197} \
198 \
199static const struct file_operations __name ## _fops = { \
200 .owner = THIS_MODULE, \
201 .open = __name ## _open, \
202 .read = seq_read, \
203 .llseek = seq_lseek, \
204 .release = seq_release, \
205}
206
207#define DEFINE_SHOW_ATTRIBUTE(__name) \
208static int __name ## _open(struct inode *inode, struct file *file) \
209{ \
210 return single_open(file, __name ## _show, inode->i_private); \
211} \
212 \
213static const struct file_operations __name ## _fops = { \
214 .owner = THIS_MODULE, \
215 .open = __name ## _open, \
216 .read = seq_read, \
217 .llseek = seq_lseek, \
218 .release = single_release, \
219}
220
221#define DEFINE_SHOW_STORE_ATTRIBUTE(__name) \
222static int __name ## _open(struct inode *inode, struct file *file) \
223{ \
224 return single_open(file, __name ## _show, inode->i_private); \
225} \
226 \
227static const struct file_operations __name ## _fops = { \
228 .owner = THIS_MODULE, \
229 .open = __name ## _open, \
230 .read = seq_read, \
231 .write = __name ## _write, \
232 .llseek = seq_lseek, \
233 .release = single_release, \
234}
235
236#define DEFINE_PROC_SHOW_ATTRIBUTE(__name) \
237static int __name ## _open(struct inode *inode, struct file *file) \
238{ \
239 return single_open(file, __name ## _show, pde_data(inode)); \
240} \
241 \
242static const struct proc_ops __name ## _proc_ops = { \
243 .proc_open = __name ## _open, \
244 .proc_read = seq_read, \
245 .proc_lseek = seq_lseek, \
246 .proc_release = single_release, \
247}
248
249static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
250{
251#ifdef CONFIG_USER_NS
252 return seq->file->f_cred->user_ns;
253#else
254 extern struct user_namespace init_user_ns;
255 return &init_user_ns;
256#endif
257}
258
259/**
260 * seq_show_options - display mount options with appropriate escapes.
261 * @m: the seq_file handle
262 * @name: the mount option name
263 * @value: the mount option name's value, can be NULL
264 */
265static inline void seq_show_option(struct seq_file *m, const char *name,
266 const char *value)
267{
268 seq_putc(m, c: ',');
269 seq_escape(m, s: name, esc: ",= \t\n\\");
270 if (value) {
271 seq_putc(m, c: '=');
272 seq_escape(m, s: value, esc: ", \t\n\\");
273 }
274}
275
276/**
277 * seq_show_option_n - display mount options with appropriate escapes
278 * where @value must be a specific length (i.e.
279 * not NUL-terminated).
280 * @m: the seq_file handle
281 * @name: the mount option name
282 * @value: the mount option name's value, cannot be NULL
283 * @length: the exact length of @value to display, must be constant expression
284 *
285 * This is a macro since this uses "length" to define the size of the
286 * stack buffer.
287 */
288#define seq_show_option_n(m, name, value, length) { \
289 char val_buf[length + 1]; \
290 memcpy(val_buf, value, length); \
291 val_buf[length] = '\0'; \
292 seq_show_option(m, name, val_buf); \
293}
294
295#define SEQ_START_TOKEN ((void *)1)
296/*
297 * Helpers for iteration over list_head-s in seq_files
298 */
299
300extern struct list_head *seq_list_start(struct list_head *head,
301 loff_t pos);
302extern struct list_head *seq_list_start_head(struct list_head *head,
303 loff_t pos);
304extern struct list_head *seq_list_next(void *v, struct list_head *head,
305 loff_t *ppos);
306
307extern struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos);
308extern struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos);
309extern struct list_head *seq_list_next_rcu(void *v, struct list_head *head, loff_t *ppos);
310
311/*
312 * Helpers for iteration over hlist_head-s in seq_files
313 */
314
315extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
316 loff_t pos);
317extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
318 loff_t pos);
319extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
320 loff_t *ppos);
321
322extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
323 loff_t pos);
324extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
325 loff_t pos);
326extern struct hlist_node *seq_hlist_next_rcu(void *v,
327 struct hlist_head *head,
328 loff_t *ppos);
329
330/* Helpers for iterating over per-cpu hlist_head-s in seq_files */
331extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
332
333extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
334
335void seq_file_init(void);
336#endif
337