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 
15 struct seq_operations;
16 
17 struct 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 
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 ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter);
112 loff_t seq_lseek(struct file *, loff_t, int);
113 int seq_release(struct inode *, struct file *);
114 int seq_write(struct seq_file *seq, const void *data, size_t len);
115 
116 __printf(2, 0)
117 void seq_vprintf(struct seq_file *m, const char *fmt, va_list args);
118 __printf(2, 3)
119 void seq_printf(struct seq_file *m, const char *fmt, ...);
120 void seq_putc(struct seq_file *m, char c);
121 void seq_puts(struct seq_file *m, const char *s);
122 void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
123 			       unsigned long long num, unsigned int width);
124 void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
125 			 unsigned long long num);
126 void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num);
127 void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
128 		    unsigned long long v, unsigned int width);
129 
130 void seq_escape_mem(struct seq_file *m, const char *src, size_t len,
131 		    unsigned int flags, const char *esc);
132 
seq_escape_str(struct seq_file * m,const char * src,unsigned int flags,const char * esc)133 static 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  */
seq_escape(struct seq_file * m,const char * s,const char * esc)150 static 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 
155 void 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 
159 int seq_path(struct seq_file *, const struct path *, const char *);
160 int seq_file_path(struct seq_file *, struct file *, const char *);
161 int seq_dentry(struct seq_file *, struct dentry *, const char *);
162 int seq_path_root(struct seq_file *m, const struct path *path,
163 		  const struct path *root, const char *esc);
164 
165 int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
166 int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
167 int single_release(struct inode *, struct file *);
168 void *__seq_open_private(struct file *, const struct seq_operations *, int);
169 int seq_open_private(struct file *, const struct seq_operations *, int);
170 int seq_release_private(struct inode *, struct file *);
171 
172 #ifdef CONFIG_BINARY_PRINTF
173 void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary);
174 #endif
175 
176 #define DEFINE_SEQ_ATTRIBUTE(__name)					\
177 static 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 									\
187 static 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)					\
196 static int __name ## _open(struct inode *inode, struct file *file)	\
197 {									\
198 	return single_open(file, __name ## _show, inode->i_private);	\
199 }									\
200 									\
201 static 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)				\
210 static int __name ## _open(struct inode *inode, struct file *file)	\
211 {									\
212 	return single_open(file, __name ## _show, PDE_DATA(inode));	\
213 }									\
214 									\
215 static 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 
seq_user_ns(struct seq_file * seq)222 static 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  */
seq_show_option(struct seq_file * m,const char * name,const char * value)238 static 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 
272 extern struct list_head *seq_list_start(struct list_head *head,
273 		loff_t pos);
274 extern struct list_head *seq_list_start_head(struct list_head *head,
275 		loff_t pos);
276 extern 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 
283 extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
284 					  loff_t pos);
285 extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
286 					       loff_t pos);
287 extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
288 					 loff_t *ppos);
289 
290 extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
291 					      loff_t pos);
292 extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
293 						   loff_t pos);
294 extern 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 */
299 extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
300 
301 extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
302 
303 void seq_file_init(void);
304 #endif
305