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/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 */
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 */
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 */
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 */
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
122 static __always_inline void seq_puts(struct seq_file *m, const char *s)
123 {
124 if (!__builtin_constant_p(*s))
125 __seq_puts(m, s);
126 else if (s[0] && !s[1])
127 seq_putc(m, s[0]);
128 else
129 seq_write(m, s, __builtin_strlen(s));
130 }
131
132 void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
133 unsigned long long num, unsigned int width);
134 void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
135 unsigned long long num);
136 void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num);
137 void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
138 unsigned long long v, unsigned int width);
139
140 void seq_escape_mem(struct seq_file *m, const char *src, size_t len,
141 unsigned int flags, const char *esc);
142
143 static inline void seq_escape_str(struct seq_file *m, const char *src,
144 unsigned int flags, const char *esc)
145 {
146 seq_escape_mem(m, src, strlen(src), flags, esc);
147 }
148
149 /**
150 * seq_escape - print string into buffer, escaping some characters
151 * @m: target buffer
152 * @s: NULL-terminated string
153 * @esc: set of characters that need escaping
154 *
155 * Puts string into buffer, replacing each occurrence of character from
156 * @esc with usual octal escape.
157 *
158 * Use seq_has_overflowed() to check for errors.
159 */
160 static inline void seq_escape(struct seq_file *m, const char *s, const char *esc)
161 {
162 seq_escape_str(m, s, ESCAPE_OCTAL, esc);
163 }
164
165 void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
166 int rowsize, int groupsize, const void *buf, size_t len,
167 bool ascii);
168
169 int seq_path(struct seq_file *, const struct path *, const char *);
170 int seq_file_path(struct seq_file *, struct file *, const char *);
171 int seq_dentry(struct seq_file *, struct dentry *, const char *);
172 int seq_path_root(struct seq_file *m, const struct path *path,
173 const struct path *root, const char *esc);
174
175 void *single_start(struct seq_file *, loff_t *);
176 int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
177 int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
178 int single_release(struct inode *, struct file *);
179 void *__seq_open_private(struct file *, const struct seq_operations *, int);
180 int seq_open_private(struct file *, const struct seq_operations *, int);
181 int seq_release_private(struct inode *, struct file *);
182
183 #ifdef CONFIG_BINARY_PRINTF
184 void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary);
185 #endif
186
187 #define DEFINE_SEQ_ATTRIBUTE(__name) \
188 static int __name ## _open(struct inode *inode, struct file *file) \
189 { \
190 int ret = seq_open(file, &__name ## _sops); \
191 if (!ret && inode->i_private) { \
192 struct seq_file *seq_f = file->private_data; \
193 seq_f->private = inode->i_private; \
194 } \
195 return ret; \
196 } \
197 \
198 static const struct file_operations __name ## _fops = { \
199 .owner = THIS_MODULE, \
200 .open = __name ## _open, \
201 .read = seq_read, \
202 .llseek = seq_lseek, \
203 .release = seq_release, \
204 }
205
206 #define DEFINE_SHOW_ATTRIBUTE(__name) \
207 static int __name ## _open(struct inode *inode, struct file *file) \
208 { \
209 return single_open(file, __name ## _show, inode->i_private); \
210 } \
211 \
212 static const struct file_operations __name ## _fops = { \
213 .owner = THIS_MODULE, \
214 .open = __name ## _open, \
215 .read = seq_read, \
216 .llseek = seq_lseek, \
217 .release = single_release, \
218 }
219
220 #define DEFINE_SHOW_STORE_ATTRIBUTE(__name) \
221 static int __name ## _open(struct inode *inode, struct file *file) \
222 { \
223 return single_open(file, __name ## _show, inode->i_private); \
224 } \
225 \
226 static const struct file_operations __name ## _fops = { \
227 .owner = THIS_MODULE, \
228 .open = __name ## _open, \
229 .read = seq_read, \
230 .write = __name ## _write, \
231 .llseek = seq_lseek, \
232 .release = single_release, \
233 }
234
235 #define DEFINE_PROC_SHOW_ATTRIBUTE(__name) \
236 static int __name ## _open(struct inode *inode, struct file *file) \
237 { \
238 return single_open(file, __name ## _show, pde_data(inode)); \
239 } \
240 \
241 static const struct proc_ops __name ## _proc_ops = { \
242 .proc_open = __name ## _open, \
243 .proc_read = seq_read, \
244 .proc_lseek = seq_lseek, \
245 .proc_release = single_release, \
246 }
247
248 static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
249 {
250 #ifdef CONFIG_USER_NS
251 return seq->file->f_cred->user_ns;
252 #else
253 extern struct user_namespace init_user_ns;
254 return &init_user_ns;
255 #endif
256 }
257
258 /**
259 * seq_show_options - display mount options with appropriate escapes.
260 * @m: the seq_file handle
261 * @name: the mount option name
262 * @value: the mount option name's value, can be NULL
263 */
264 static inline void seq_show_option(struct seq_file *m, const char *name,
265 const char *value)
266 {
267 seq_putc(m, ',');
268 seq_escape(m, name, ",= \t\n\\");
269 if (value) {
270 seq_putc(m, '=');
271 seq_escape(m, value, ", \t\n\\");
272 }
273 }
274
275 /**
276 * seq_show_option_n - display mount options with appropriate escapes
277 * where @value must be a specific length (i.e.
278 * not NUL-terminated).
279 * @m: the seq_file handle
280 * @name: the mount option name
281 * @value: the mount option name's value, cannot be NULL
282 * @length: the exact length of @value to display, must be constant expression
283 *
284 * This is a macro since this uses "length" to define the size of the
285 * stack buffer.
286 */
287 #define seq_show_option_n(m, name, value, length) { \
288 char val_buf[length + 1]; \
289 memcpy(val_buf, value, length); \
290 val_buf[length] = '\0'; \
291 seq_show_option(m, name, val_buf); \
292 }
293
294 #define SEQ_START_TOKEN ((void *)1)
295 /*
296 * Helpers for iteration over list_head-s in seq_files
297 */
298
299 extern struct list_head *seq_list_start(struct list_head *head,
300 loff_t pos);
301 extern struct list_head *seq_list_start_head(struct list_head *head,
302 loff_t pos);
303 extern struct list_head *seq_list_next(void *v, struct list_head *head,
304 loff_t *ppos);
305
306 extern struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos);
307 extern struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos);
308 extern struct list_head *seq_list_next_rcu(void *v, struct list_head *head, loff_t *ppos);
309
310 /*
311 * Helpers for iteration over hlist_head-s in seq_files
312 */
313
314 extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
315 loff_t pos);
316 extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
317 loff_t pos);
318 extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
319 loff_t *ppos);
320
321 extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
322 loff_t pos);
323 extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
324 loff_t pos);
325 extern struct hlist_node *seq_hlist_next_rcu(void *v,
326 struct hlist_head *head,
327 loff_t *ppos);
328
329 /* Helpers for iterating over per-cpu hlist_head-s in seq_files */
330 extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
331
332 extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
333
334 void seq_file_init(void);
335 #endif
336
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