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
165int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
166int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
167int single_release(struct inode *, struct file *);
168void *__seq_open_private(struct file *, const struct seq_operations *, int);
169int seq_open_private(struct file *, const struct seq_operations *, int);
170int seq_release_private(struct inode *, struct file *);
171
172#ifdef CONFIG_BINARY_PRINTF
173void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary);
174#endif
175
176#define DEFINE_SEQ_ATTRIBUTE(__name)					\
177static int __name ## _open(struct inode *inode, struct file *file)	\
178{									\
179	int ret = seq_open(file, &__name ## _sops);			\
180	if (!ret && inode->i_private) {					\
181		struct seq_file *seq_f = file->private_data;		\
182		seq_f->private = inode->i_private;			\
183	}								\
184	return ret;							\
185}									\
186									\
187static const struct file_operations __name ## _fops = {			\
188	.owner		= THIS_MODULE,					\
189	.open		= __name ## _open,				\
190	.read		= seq_read,					\
191	.llseek		= seq_lseek,					\
192	.release	= seq_release,					\
193}
194
195#define DEFINE_SHOW_ATTRIBUTE(__name)					\
196static int __name ## _open(struct inode *inode, struct file *file)	\
197{									\
198	return single_open(file, __name ## _show, inode->i_private);	\
199}									\
200									\
201static const struct file_operations __name ## _fops = {			\
202	.owner		= THIS_MODULE,					\
203	.open		= __name ## _open,				\
204	.read		= seq_read,					\
205	.llseek		= seq_lseek,					\
206	.release	= single_release,				\
207}
208
209#define DEFINE_PROC_SHOW_ATTRIBUTE(__name)				\
210static int __name ## _open(struct inode *inode, struct file *file)	\
211{									\
212	return single_open(file, __name ## _show, PDE_DATA(inode));	\
213}									\
214									\
215static const struct proc_ops __name ## _proc_ops = {			\
216	.proc_open	= __name ## _open,				\
217	.proc_read	= seq_read,					\
218	.proc_lseek	= seq_lseek,					\
219	.proc_release	= single_release,				\
220}
221
222static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
223{
224#ifdef CONFIG_USER_NS
225	return seq->file->f_cred->user_ns;
226#else
227	extern struct user_namespace init_user_ns;
228	return &init_user_ns;
229#endif
230}
231
232/**
233 * seq_show_options - display mount options with appropriate escapes.
234 * @m: the seq_file handle
235 * @name: the mount option name
236 * @value: the mount option name's value, can be NULL
237 */
238static inline void seq_show_option(struct seq_file *m, const char *name,
239				   const char *value)
240{
241	seq_putc(m, ',');
242	seq_escape(m, name, ",= \t\n\\");
243	if (value) {
244		seq_putc(m, '=');
245		seq_escape(m, value, ", \t\n\\");
246	}
247}
248
249/**
250 * seq_show_option_n - display mount options with appropriate escapes
251 *		       where @value must be a specific length.
252 * @m: the seq_file handle
253 * @name: the mount option name
254 * @value: the mount option name's value, cannot be NULL
255 * @length: the length of @value to display
256 *
257 * This is a macro since this uses "length" to define the size of the
258 * stack buffer.
259 */
260#define seq_show_option_n(m, name, value, length) {	\
261	char val_buf[length + 1];			\
262	strncpy(val_buf, value, length);		\
263	val_buf[length] = '\0';				\
264	seq_show_option(m, name, val_buf);		\
265}
266
267#define SEQ_START_TOKEN ((void *)1)
268/*
269 * Helpers for iteration over list_head-s in seq_files
270 */
271
272extern struct list_head *seq_list_start(struct list_head *head,
273		loff_t pos);
274extern struct list_head *seq_list_start_head(struct list_head *head,
275		loff_t pos);
276extern struct list_head *seq_list_next(void *v, struct list_head *head,
277		loff_t *ppos);
278
279/*
280 * Helpers for iteration over hlist_head-s in seq_files
281 */
282
283extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
284					  loff_t pos);
285extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
286					       loff_t pos);
287extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
288					 loff_t *ppos);
289
290extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
291					      loff_t pos);
292extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
293						   loff_t pos);
294extern struct hlist_node *seq_hlist_next_rcu(void *v,
295						   struct hlist_head *head,
296						   loff_t *ppos);
297
298/* Helpers for iterating over per-cpu hlist_head-s in seq_files */
299extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
300
301extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
302
303void seq_file_init(void);
304#endif
305