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 void *single_start(struct seq_file *, loff_t *);
166 int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
167 int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
168 int single_release(struct inode *, struct file *);
169 void *__seq_open_private(struct file *, const struct seq_operations *, int);
170 int seq_open_private(struct file *, const struct seq_operations *, int);
171 int seq_release_private(struct inode *, struct file *);
172
173 #ifdef CONFIG_BINARY_PRINTF
174 void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary);
175 #endif
176
177 #define DEFINE_SEQ_ATTRIBUTE(__name) \
178 static int __name ## _open(struct inode *inode, struct file *file) \
179 { \
180 int ret = seq_open(file, &__name ## _sops); \
181 if (!ret && inode->i_private) { \
182 struct seq_file *seq_f = file->private_data; \
183 seq_f->private = inode->i_private; \
184 } \
185 return ret; \
186 } \
187 \
188 static const struct file_operations __name ## _fops = { \
189 .owner = THIS_MODULE, \
190 .open = __name ## _open, \
191 .read = seq_read, \
192 .llseek = seq_lseek, \
193 .release = seq_release, \
194 }
195
196 #define DEFINE_SHOW_ATTRIBUTE(__name) \
197 static int __name ## _open(struct inode *inode, struct file *file) \
198 { \
199 return single_open(file, __name ## _show, inode->i_private); \
200 } \
201 \
202 static const struct file_operations __name ## _fops = { \
203 .owner = THIS_MODULE, \
204 .open = __name ## _open, \
205 .read = seq_read, \
206 .llseek = seq_lseek, \
207 .release = single_release, \
208 }
209
210 #define DEFINE_PROC_SHOW_ATTRIBUTE(__name) \
211 static int __name ## _open(struct inode *inode, struct file *file) \
212 { \
213 return single_open(file, __name ## _show, pde_data(inode)); \
214 } \
215 \
216 static const struct proc_ops __name ## _proc_ops = { \
217 .proc_open = __name ## _open, \
218 .proc_read = seq_read, \
219 .proc_lseek = seq_lseek, \
220 .proc_release = single_release, \
221 }
222
seq_user_ns(struct seq_file * seq)223 static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
224 {
225 #ifdef CONFIG_USER_NS
226 return seq->file->f_cred->user_ns;
227 #else
228 extern struct user_namespace init_user_ns;
229 return &init_user_ns;
230 #endif
231 }
232
233 /**
234 * seq_show_options - display mount options with appropriate escapes.
235 * @m: the seq_file handle
236 * @name: the mount option name
237 * @value: the mount option name's value, can be NULL
238 */
seq_show_option(struct seq_file * m,const char * name,const char * value)239 static inline void seq_show_option(struct seq_file *m, const char *name,
240 const char *value)
241 {
242 seq_putc(m, ',');
243 seq_escape(m, name, ",= \t\n\\");
244 if (value) {
245 seq_putc(m, '=');
246 seq_escape(m, value, ", \t\n\\");
247 }
248 }
249
250 /**
251 * seq_show_option_n - display mount options with appropriate escapes
252 * where @value must be a specific length (i.e.
253 * not NUL-terminated).
254 * @m: the seq_file handle
255 * @name: the mount option name
256 * @value: the mount option name's value, cannot be NULL
257 * @length: the exact length of @value to display, must be constant expression
258 *
259 * This is a macro since this uses "length" to define the size of the
260 * stack buffer.
261 */
262 #define seq_show_option_n(m, name, value, length) { \
263 char val_buf[length + 1]; \
264 memcpy(val_buf, value, length); \
265 val_buf[length] = '\0'; \
266 seq_show_option(m, name, val_buf); \
267 }
268
269 #define SEQ_START_TOKEN ((void *)1)
270 /*
271 * Helpers for iteration over list_head-s in seq_files
272 */
273
274 extern struct list_head *seq_list_start(struct list_head *head,
275 loff_t pos);
276 extern struct list_head *seq_list_start_head(struct list_head *head,
277 loff_t pos);
278 extern struct list_head *seq_list_next(void *v, struct list_head *head,
279 loff_t *ppos);
280
281 extern struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos);
282 extern struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos);
283 extern struct list_head *seq_list_next_rcu(void *v, struct list_head *head, loff_t *ppos);
284
285 /*
286 * Helpers for iteration over hlist_head-s in seq_files
287 */
288
289 extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
290 loff_t pos);
291 extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
292 loff_t pos);
293 extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
294 loff_t *ppos);
295
296 extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
297 loff_t pos);
298 extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
299 loff_t pos);
300 extern struct hlist_node *seq_hlist_next_rcu(void *v,
301 struct hlist_head *head,
302 loff_t *ppos);
303
304 /* Helpers for iterating over per-cpu hlist_head-s in seq_files */
305 extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
306
307 extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
308
309 void seq_file_init(void);
310 #endif
311