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

source code of linux/include/linux/seq_file.h