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(struct seq_file *m, const char *s, const char *esc);
130 void seq_escape_mem_ascii(struct seq_file *m, const char *src, size_t isz);
131
132 void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
133 int rowsize, int groupsize, const void *buf, size_t len,
134 bool ascii);
135
136 int seq_path(struct seq_file *, const struct path *, const char *);
137 int seq_file_path(struct seq_file *, struct file *, const char *);
138 int seq_dentry(struct seq_file *, struct dentry *, const char *);
139 int seq_path_root(struct seq_file *m, const struct path *path,
140 const struct path *root, const char *esc);
141
142 int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
143 int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
144 int single_release(struct inode *, struct file *);
145 void *__seq_open_private(struct file *, const struct seq_operations *, int);
146 int seq_open_private(struct file *, const struct seq_operations *, int);
147 int seq_release_private(struct inode *, struct file *);
148
149 #define DEFINE_SEQ_ATTRIBUTE(__name) \
150 static int __name ## _open(struct inode *inode, struct file *file) \
151 { \
152 int ret = seq_open(file, &__name ## _sops); \
153 if (!ret && inode->i_private) { \
154 struct seq_file *seq_f = file->private_data; \
155 seq_f->private = inode->i_private; \
156 } \
157 return ret; \
158 } \
159 \
160 static const struct file_operations __name ## _fops = { \
161 .owner = THIS_MODULE, \
162 .open = __name ## _open, \
163 .read = seq_read, \
164 .llseek = seq_lseek, \
165 .release = seq_release, \
166 }
167
168 #define DEFINE_SHOW_ATTRIBUTE(__name) \
169 static int __name ## _open(struct inode *inode, struct file *file) \
170 { \
171 return single_open(file, __name ## _show, inode->i_private); \
172 } \
173 \
174 static const struct file_operations __name ## _fops = { \
175 .owner = THIS_MODULE, \
176 .open = __name ## _open, \
177 .read = seq_read, \
178 .llseek = seq_lseek, \
179 .release = single_release, \
180 }
181
182 #define DEFINE_PROC_SHOW_ATTRIBUTE(__name) \
183 static int __name ## _open(struct inode *inode, struct file *file) \
184 { \
185 return single_open(file, __name ## _show, PDE_DATA(inode)); \
186 } \
187 \
188 static const struct proc_ops __name ## _proc_ops = { \
189 .proc_open = __name ## _open, \
190 .proc_read = seq_read, \
191 .proc_lseek = seq_lseek, \
192 .proc_release = single_release, \
193 }
194
seq_user_ns(struct seq_file * seq)195 static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
196 {
197 #ifdef CONFIG_USER_NS
198 return seq->file->f_cred->user_ns;
199 #else
200 extern struct user_namespace init_user_ns;
201 return &init_user_ns;
202 #endif
203 }
204
205 /**
206 * seq_show_options - display mount options with appropriate escapes.
207 * @m: the seq_file handle
208 * @name: the mount option name
209 * @value: the mount option name's value, can be NULL
210 */
seq_show_option(struct seq_file * m,const char * name,const char * value)211 static inline void seq_show_option(struct seq_file *m, const char *name,
212 const char *value)
213 {
214 seq_putc(m, ',');
215 seq_escape(m, name, ",= \t\n\\");
216 if (value) {
217 seq_putc(m, '=');
218 seq_escape(m, value, ", \t\n\\");
219 }
220 }
221
222 /**
223 * seq_show_option_n - display mount options with appropriate escapes
224 * where @value must be a specific length.
225 * @m: the seq_file handle
226 * @name: the mount option name
227 * @value: the mount option name's value, cannot be NULL
228 * @length: the length of @value to display
229 *
230 * This is a macro since this uses "length" to define the size of the
231 * stack buffer.
232 */
233 #define seq_show_option_n(m, name, value, length) { \
234 char val_buf[length + 1]; \
235 strncpy(val_buf, value, length); \
236 val_buf[length] = '\0'; \
237 seq_show_option(m, name, val_buf); \
238 }
239
240 #define SEQ_START_TOKEN ((void *)1)
241 /*
242 * Helpers for iteration over list_head-s in seq_files
243 */
244
245 extern struct list_head *seq_list_start(struct list_head *head,
246 loff_t pos);
247 extern struct list_head *seq_list_start_head(struct list_head *head,
248 loff_t pos);
249 extern struct list_head *seq_list_next(void *v, struct list_head *head,
250 loff_t *ppos);
251
252 /*
253 * Helpers for iteration over hlist_head-s in seq_files
254 */
255
256 extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
257 loff_t pos);
258 extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
259 loff_t pos);
260 extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
261 loff_t *ppos);
262
263 extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
264 loff_t pos);
265 extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
266 loff_t pos);
267 extern struct hlist_node *seq_hlist_next_rcu(void *v,
268 struct hlist_head *head,
269 loff_t *ppos);
270
271 /* Helpers for iterating over per-cpu hlist_head-s in seq_files */
272 extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
273
274 extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
275
276 void seq_file_init(void);
277 #endif
278