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