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 */ 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 loff_t seq_lseek(struct file *, loff_t, int); 111 int seq_release(struct inode *, struct file *); 112 int seq_write(struct seq_file *seq, const void *data, size_t len); 113 114 __printf(2, 0) 115 void seq_vprintf(struct seq_file *m, const char *fmt, va_list args); 116 __printf(2, 3) 117 void seq_printf(struct seq_file *m, const char *fmt, ...); 118 void seq_putc(struct seq_file *m, char c); 119 void seq_puts(struct seq_file *m, const char *s); 120 void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter, 121 unsigned long long num, unsigned int width); 122 void seq_put_decimal_ull(struct seq_file *m, const char *delimiter, 123 unsigned long long num); 124 void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num); 125 void seq_put_hex_ll(struct seq_file *m, const char *delimiter, 126 unsigned long long v, unsigned int width); 127 128 void seq_escape(struct seq_file *m, const char *s, const char *esc); 129 void seq_escape_mem_ascii(struct seq_file *m, const char *src, size_t isz); 130 131 void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type, 132 int rowsize, int groupsize, const void *buf, size_t len, 133 bool ascii); 134 135 int seq_path(struct seq_file *, const struct path *, const char *); 136 int seq_file_path(struct seq_file *, struct file *, const char *); 137 int seq_dentry(struct seq_file *, struct dentry *, const char *); 138 int seq_path_root(struct seq_file *m, const struct path *path, 139 const struct path *root, const char *esc); 140 141 int single_open(struct file *, int (*)(struct seq_file *, void *), void *); 142 int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t); 143 int single_release(struct inode *, struct file *); 144 void *__seq_open_private(struct file *, const struct seq_operations *, int); 145 int seq_open_private(struct file *, const struct seq_operations *, int); 146 int seq_release_private(struct inode *, struct file *); 147 148 #define DEFINE_SEQ_ATTRIBUTE(__name) \ 149 static int __name ## _open(struct inode *inode, struct file *file) \ 150 { \ 151 int ret = seq_open(file, &__name ## _sops); \ 152 if (!ret && inode->i_private) { \ 153 struct seq_file *seq_f = file->private_data; \ 154 seq_f->private = inode->i_private; \ 155 } \ 156 return ret; \ 157 } \ 158 \ 159 static const struct file_operations __name ## _fops = { \ 160 .owner = THIS_MODULE, \ 161 .open = __name ## _open, \ 162 .read = seq_read, \ 163 .llseek = seq_lseek, \ 164 .release = seq_release, \ 165 } 166 167 #define DEFINE_SHOW_ATTRIBUTE(__name) \ 168 static int __name ## _open(struct inode *inode, struct file *file) \ 169 { \ 170 return single_open(file, __name ## _show, inode->i_private); \ 171 } \ 172 \ 173 static const struct file_operations __name ## _fops = { \ 174 .owner = THIS_MODULE, \ 175 .open = __name ## _open, \ 176 .read = seq_read, \ 177 .llseek = seq_lseek, \ 178 .release = single_release, \ 179 } 180 181 #define DEFINE_PROC_SHOW_ATTRIBUTE(__name) \ 182 static int __name ## _open(struct inode *inode, struct file *file) \ 183 { \ 184 return single_open(file, __name ## _show, inode->i_private); \ 185 } \ 186 \ 187 static const struct proc_ops __name ## _proc_ops = { \ 188 .proc_open = __name ## _open, \ 189 .proc_read = seq_read, \ 190 .proc_lseek = seq_lseek, \ 191 .proc_release = single_release, \ 192 } 193 194 static inline struct user_namespace *seq_user_ns(struct seq_file *seq) 195 { 196 #ifdef CONFIG_USER_NS 197 return seq->file->f_cred->user_ns; 198 #else 199 extern struct user_namespace init_user_ns; 200 return &init_user_ns; 201 #endif 202 } 203 204 /** 205 * seq_show_options - display mount options with appropriate escapes. 206 * @m: the seq_file handle 207 * @name: the mount option name 208 * @value: the mount option name's value, can be NULL 209 */ 210 static inline void seq_show_option(struct seq_file *m, const char *name, 211 const char *value) 212 { 213 seq_putc(m, ','); 214 seq_escape(m, name, ",= \t\n\\"); 215 if (value) { 216 seq_putc(m, '='); 217 seq_escape(m, value, ", \t\n\\"); 218 } 219 } 220 221 /** 222 * seq_show_option_n - display mount options with appropriate escapes 223 * where @value must be a specific length. 224 * @m: the seq_file handle 225 * @name: the mount option name 226 * @value: the mount option name's value, cannot be NULL 227 * @length: the length of @value to display 228 * 229 * This is a macro since this uses "length" to define the size of the 230 * stack buffer. 231 */ 232 #define seq_show_option_n(m, name, value, length) { \ 233 char val_buf[length + 1]; \ 234 strncpy(val_buf, value, length); \ 235 val_buf[length] = '\0'; \ 236 seq_show_option(m, name, val_buf); \ 237 } 238 239 #define SEQ_START_TOKEN ((void *)1) 240 /* 241 * Helpers for iteration over list_head-s in seq_files 242 */ 243 244 extern struct list_head *seq_list_start(struct list_head *head, 245 loff_t pos); 246 extern struct list_head *seq_list_start_head(struct list_head *head, 247 loff_t pos); 248 extern struct list_head *seq_list_next(void *v, struct list_head *head, 249 loff_t *ppos); 250 251 /* 252 * Helpers for iteration over hlist_head-s in seq_files 253 */ 254 255 extern struct hlist_node *seq_hlist_start(struct hlist_head *head, 256 loff_t pos); 257 extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head, 258 loff_t pos); 259 extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head, 260 loff_t *ppos); 261 262 extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head, 263 loff_t pos); 264 extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head, 265 loff_t pos); 266 extern struct hlist_node *seq_hlist_next_rcu(void *v, 267 struct hlist_head *head, 268 loff_t *ppos); 269 270 /* Helpers for iterating over per-cpu hlist_head-s in seq_files */ 271 extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos); 272 273 extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos); 274 275 void seq_file_init(void); 276 #endif 277