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 
14 struct seq_operations;
15 
16 struct 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 
32 struct 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  */
seq_has_overflowed(struct seq_file * m)51 static 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  */
seq_get_buf(struct seq_file * m,char ** bufp)64 static 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  */
seq_commit(struct seq_file * m,int num)84 static 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  */
seq_setwidth(struct seq_file * m,size_t size)102 static inline void seq_setwidth(struct seq_file *m, size_t size)
103 {
104 	m->pad_until = m->count + size;
105 }
106 void seq_pad(struct seq_file *m, char c);
107 
108 char *mangle_path(char *s, const char *p, const char *esc);
109 int seq_open(struct file *, const struct seq_operations *);
110 ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);
111 loff_t seq_lseek(struct file *, loff_t, int);
112 int seq_release(struct inode *, struct file *);
113 int seq_write(struct seq_file *seq, const void *data, size_t len);
114 
115 __printf(2, 0)
116 void seq_vprintf(struct seq_file *m, const char *fmt, va_list args);
117 __printf(2, 3)
118 void seq_printf(struct seq_file *m, const char *fmt, ...);
119 void seq_putc(struct seq_file *m, char c);
120 void seq_puts(struct seq_file *m, const char *s);
121 void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
122 			       unsigned long long num, unsigned int width);
123 void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
124 			 unsigned long long num);
125 void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num);
126 void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
127 		    unsigned long long v, unsigned int width);
128 
129 void seq_escape(struct seq_file *m, const char *s, const char *esc);
130 
131 void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
132 		  int rowsize, int groupsize, const void *buf, size_t len,
133 		  bool ascii);
134 
135 int seq_path(struct seq_file *, const struct path *, const char *);
136 int seq_file_path(struct seq_file *, struct file *, const char *);
137 int seq_dentry(struct seq_file *, struct dentry *, const char *);
138 int seq_path_root(struct seq_file *m, const struct path *path,
139 		  const struct path *root, const char *esc);
140 
141 int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
142 int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
143 int single_release(struct inode *, struct file *);
144 void *__seq_open_private(struct file *, const struct seq_operations *, int);
145 int seq_open_private(struct file *, const struct seq_operations *, int);
146 int seq_release_private(struct inode *, struct file *);
147 
148 #define DEFINE_SHOW_ATTRIBUTE(__name)					\
149 static int __name ## _open(struct inode *inode, struct file *file)	\
150 {									\
151 	return single_open(file, __name ## _show, inode->i_private);	\
152 }									\
153 									\
154 static const struct file_operations __name ## _fops = {			\
155 	.owner		= THIS_MODULE,					\
156 	.open		= __name ## _open,				\
157 	.read		= seq_read,					\
158 	.llseek		= seq_lseek,					\
159 	.release	= single_release,				\
160 }
161 
seq_user_ns(struct seq_file * seq)162 static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
163 {
164 #ifdef CONFIG_USER_NS
165 	return seq->file->f_cred->user_ns;
166 #else
167 	extern struct user_namespace init_user_ns;
168 	return &init_user_ns;
169 #endif
170 }
171 
172 /**
173  * seq_show_options - display mount options with appropriate escapes.
174  * @m: the seq_file handle
175  * @name: the mount option name
176  * @value: the mount option name's value, can be NULL
177  */
seq_show_option(struct seq_file * m,const char * name,const char * value)178 static inline void seq_show_option(struct seq_file *m, const char *name,
179 				   const char *value)
180 {
181 	seq_putc(m, ',');
182 	seq_escape(m, name, ",= \t\n\\");
183 	if (value) {
184 		seq_putc(m, '=');
185 		seq_escape(m, value, ", \t\n\\");
186 	}
187 }
188 
189 /**
190  * seq_show_option_n - display mount options with appropriate escapes
191  *		       where @value must be a specific length.
192  * @m: the seq_file handle
193  * @name: the mount option name
194  * @value: the mount option name's value, cannot be NULL
195  * @length: the length of @value to display
196  *
197  * This is a macro since this uses "length" to define the size of the
198  * stack buffer.
199  */
200 #define seq_show_option_n(m, name, value, length) {	\
201 	char val_buf[length + 1];			\
202 	strncpy(val_buf, value, length);		\
203 	val_buf[length] = '\0';				\
204 	seq_show_option(m, name, val_buf);		\
205 }
206 
207 #define SEQ_START_TOKEN ((void *)1)
208 /*
209  * Helpers for iteration over list_head-s in seq_files
210  */
211 
212 extern struct list_head *seq_list_start(struct list_head *head,
213 		loff_t pos);
214 extern struct list_head *seq_list_start_head(struct list_head *head,
215 		loff_t pos);
216 extern struct list_head *seq_list_next(void *v, struct list_head *head,
217 		loff_t *ppos);
218 
219 /*
220  * Helpers for iteration over hlist_head-s in seq_files
221  */
222 
223 extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
224 					  loff_t pos);
225 extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
226 					       loff_t pos);
227 extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
228 					 loff_t *ppos);
229 
230 extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
231 					      loff_t pos);
232 extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
233 						   loff_t pos);
234 extern struct hlist_node *seq_hlist_next_rcu(void *v,
235 						   struct hlist_head *head,
236 						   loff_t *ppos);
237 
238 /* Helpers for iterating over per-cpu hlist_head-s in seq_files */
239 extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
240 
241 extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
242 
243 void seq_file_init(void);
244 #endif
245