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 */ 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 */ 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 */ 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 */ 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); 132 133 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 */ 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 int single_open(struct file *, int (*)(struct seq_file *, void *), void *); 166 int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t); 167 int single_release(struct inode *, struct file *); 168 void *__seq_open_private(struct file *, const struct seq_operations *, int); 169 int seq_open_private(struct file *, const struct seq_operations *, int); 170 int seq_release_private(struct inode *, struct file *); 171 172 #ifdef CONFIG_BINARY_PRINTF 173 void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary); 174 #endif 175 176 #define DEFINE_SEQ_ATTRIBUTE(__name) \ 177 static int __name ## _open(struct inode *inode, struct file *file) \ 178 { \ 179 int ret = seq_open(file, &__name ## _sops); \ 180 if (!ret && inode->i_private) { \ 181 struct seq_file *seq_f = file->private_data; \ 182 seq_f->private = inode->i_private; \ 183 } \ 184 return ret; \ 185 } \ 186 \ 187 static const struct file_operations __name ## _fops = { \ 188 .owner = THIS_MODULE, \ 189 .open = __name ## _open, \ 190 .read = seq_read, \ 191 .llseek = seq_lseek, \ 192 .release = seq_release, \ 193 } 194 195 #define DEFINE_SHOW_ATTRIBUTE(__name) \ 196 static int __name ## _open(struct inode *inode, struct file *file) \ 197 { \ 198 return single_open(file, __name ## _show, inode->i_private); \ 199 } \ 200 \ 201 static const struct file_operations __name ## _fops = { \ 202 .owner = THIS_MODULE, \ 203 .open = __name ## _open, \ 204 .read = seq_read, \ 205 .llseek = seq_lseek, \ 206 .release = single_release, \ 207 } 208 209 #define DEFINE_PROC_SHOW_ATTRIBUTE(__name) \ 210 static int __name ## _open(struct inode *inode, struct file *file) \ 211 { \ 212 return single_open(file, __name ## _show, pde_data(inode)); \ 213 } \ 214 \ 215 static const struct proc_ops __name ## _proc_ops = { \ 216 .proc_open = __name ## _open, \ 217 .proc_read = seq_read, \ 218 .proc_lseek = seq_lseek, \ 219 .proc_release = single_release, \ 220 } 221 222 static inline struct user_namespace *seq_user_ns(struct seq_file *seq) 223 { 224 #ifdef CONFIG_USER_NS 225 return seq->file->f_cred->user_ns; 226 #else 227 extern struct user_namespace init_user_ns; 228 return &init_user_ns; 229 #endif 230 } 231 232 /** 233 * seq_show_options - display mount options with appropriate escapes. 234 * @m: the seq_file handle 235 * @name: the mount option name 236 * @value: the mount option name's value, can be NULL 237 */ 238 static inline void seq_show_option(struct seq_file *m, const char *name, 239 const char *value) 240 { 241 seq_putc(m, ','); 242 seq_escape(m, name, ",= \t\n\\"); 243 if (value) { 244 seq_putc(m, '='); 245 seq_escape(m, value, ", \t\n\\"); 246 } 247 } 248 249 /** 250 * seq_show_option_n - display mount options with appropriate escapes 251 * where @value must be a specific length. 252 * @m: the seq_file handle 253 * @name: the mount option name 254 * @value: the mount option name's value, cannot be NULL 255 * @length: the length of @value to display 256 * 257 * This is a macro since this uses "length" to define the size of the 258 * stack buffer. 259 */ 260 #define seq_show_option_n(m, name, value, length) { \ 261 char val_buf[length + 1]; \ 262 strncpy(val_buf, value, length); \ 263 val_buf[length] = '\0'; \ 264 seq_show_option(m, name, val_buf); \ 265 } 266 267 #define SEQ_START_TOKEN ((void *)1) 268 /* 269 * Helpers for iteration over list_head-s in seq_files 270 */ 271 272 extern struct list_head *seq_list_start(struct list_head *head, 273 loff_t pos); 274 extern struct list_head *seq_list_start_head(struct list_head *head, 275 loff_t pos); 276 extern struct list_head *seq_list_next(void *v, struct list_head *head, 277 loff_t *ppos); 278 279 /* 280 * Helpers for iteration over hlist_head-s in seq_files 281 */ 282 283 extern struct hlist_node *seq_hlist_start(struct hlist_head *head, 284 loff_t pos); 285 extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head, 286 loff_t pos); 287 extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head, 288 loff_t *ppos); 289 290 extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head, 291 loff_t pos); 292 extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head, 293 loff_t pos); 294 extern struct hlist_node *seq_hlist_next_rcu(void *v, 295 struct hlist_head *head, 296 loff_t *ppos); 297 298 /* Helpers for iterating over per-cpu hlist_head-s in seq_files */ 299 extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos); 300 301 extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos); 302 303 void seq_file_init(void); 304 #endif 305