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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/bug.h>
8#include <linux/mutex.h>
9#include <linux/cpumask.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 u64 version;
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 *);
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);
121void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
122 unsigned long long num);
123void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num);
124void seq_escape(struct seq_file *m, const char *s, const char *esc);
125
126void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
127 int rowsize, int groupsize, const void *buf, size_t len,
128 bool ascii);
129
130int seq_path(struct seq_file *, const struct path *, const char *);
131int seq_file_path(struct seq_file *, struct file *, const char *);
132int seq_dentry(struct seq_file *, struct dentry *, const char *);
133int seq_path_root(struct seq_file *m, const struct path *path,
134 const struct path *root, const char *esc);
135
136int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
137int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
138int single_release(struct inode *, struct file *);
139void *__seq_open_private(struct file *, const struct seq_operations *, int);
140int seq_open_private(struct file *, const struct seq_operations *, int);
141int seq_release_private(struct inode *, struct file *);
142
143static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
144{
145#ifdef CONFIG_USER_NS
146 return seq->file->f_cred->user_ns;
147#else
148 extern struct user_namespace init_user_ns;
149 return &init_user_ns;
150#endif
151}
152
153/**
154 * seq_show_options - display mount options with appropriate escapes.
155 * @m: the seq_file handle
156 * @name: the mount option name
157 * @value: the mount option name's value, can be NULL
158 */
159static inline void seq_show_option(struct seq_file *m, const char *name,
160 const char *value)
161{
162 seq_putc(m, ',');
163 seq_escape(m, name, ",= \t\n\\");
164 if (value) {
165 seq_putc(m, '=');
166 seq_escape(m, value, ", \t\n\\");
167 }
168}
169
170/**
171 * seq_show_option_n - display mount options with appropriate escapes
172 * where @value must be a specific length.
173 * @m: the seq_file handle
174 * @name: the mount option name
175 * @value: the mount option name's value, cannot be NULL
176 * @length: the length of @value to display
177 *
178 * This is a macro since this uses "length" to define the size of the
179 * stack buffer.
180 */
181#define seq_show_option_n(m, name, value, length) { \
182 char val_buf[length + 1]; \
183 strncpy(val_buf, value, length); \
184 val_buf[length] = '\0'; \
185 seq_show_option(m, name, val_buf); \
186}
187
188#define SEQ_START_TOKEN ((void *)1)
189/*
190 * Helpers for iteration over list_head-s in seq_files
191 */
192
193extern struct list_head *seq_list_start(struct list_head *head,
194 loff_t pos);
195extern struct list_head *seq_list_start_head(struct list_head *head,
196 loff_t pos);
197extern struct list_head *seq_list_next(void *v, struct list_head *head,
198 loff_t *ppos);
199
200/*
201 * Helpers for iteration over hlist_head-s in seq_files
202 */
203
204extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
205 loff_t pos);
206extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
207 loff_t pos);
208extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
209 loff_t *ppos);
210
211extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
212 loff_t pos);
213extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
214 loff_t pos);
215extern struct hlist_node *seq_hlist_next_rcu(void *v,
216 struct hlist_head *head,
217 loff_t *ppos);
218
219/* Helpers for iterating over per-cpu hlist_head-s in seq_files */
220extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
221
222extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
223
224#endif