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 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_mem(struct seq_file *m, const char *src, size_t len, 130 unsigned int flags, const char *esc); 131 132 static inline void seq_escape_str(struct seq_file *m, const char *src, 133 unsigned int flags, const char *esc) 134 { 135 seq_escape_mem(m, src, strlen(src), flags, esc); 136 } 137 138 void seq_escape(struct seq_file *m, const char *s, const char *esc); 139 140 void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type, 141 int rowsize, int groupsize, const void *buf, size_t len, 142 bool ascii); 143 144 int seq_path(struct seq_file *, const struct path *, const char *); 145 int seq_file_path(struct seq_file *, struct file *, const char *); 146 int seq_dentry(struct seq_file *, struct dentry *, const char *); 147 int seq_path_root(struct seq_file *m, const struct path *path, 148 const struct path *root, const char *esc); 149 150 int single_open(struct file *, int (*)(struct seq_file *, void *), void *); 151 int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t); 152 int single_release(struct inode *, struct file *); 153 void *__seq_open_private(struct file *, const struct seq_operations *, int); 154 int seq_open_private(struct file *, const struct seq_operations *, int); 155 int seq_release_private(struct inode *, struct file *); 156 157 #ifdef CONFIG_BINARY_PRINTF 158 void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary); 159 #endif 160 161 #define DEFINE_SEQ_ATTRIBUTE(__name) \ 162 static int __name ## _open(struct inode *inode, struct file *file) \ 163 { \ 164 int ret = seq_open(file, &__name ## _sops); \ 165 if (!ret && inode->i_private) { \ 166 struct seq_file *seq_f = file->private_data; \ 167 seq_f->private = inode->i_private; \ 168 } \ 169 return ret; \ 170 } \ 171 \ 172 static const struct file_operations __name ## _fops = { \ 173 .owner = THIS_MODULE, \ 174 .open = __name ## _open, \ 175 .read = seq_read, \ 176 .llseek = seq_lseek, \ 177 .release = seq_release, \ 178 } 179 180 #define DEFINE_SHOW_ATTRIBUTE(__name) \ 181 static int __name ## _open(struct inode *inode, struct file *file) \ 182 { \ 183 return single_open(file, __name ## _show, inode->i_private); \ 184 } \ 185 \ 186 static const struct file_operations __name ## _fops = { \ 187 .owner = THIS_MODULE, \ 188 .open = __name ## _open, \ 189 .read = seq_read, \ 190 .llseek = seq_lseek, \ 191 .release = single_release, \ 192 } 193 194 #define DEFINE_PROC_SHOW_ATTRIBUTE(__name) \ 195 static int __name ## _open(struct inode *inode, struct file *file) \ 196 { \ 197 return single_open(file, __name ## _show, inode->i_private); \ 198 } \ 199 \ 200 static const struct proc_ops __name ## _proc_ops = { \ 201 .proc_open = __name ## _open, \ 202 .proc_read = seq_read, \ 203 .proc_lseek = seq_lseek, \ 204 .proc_release = single_release, \ 205 } 206 207 static inline struct user_namespace *seq_user_ns(struct seq_file *seq) 208 { 209 #ifdef CONFIG_USER_NS 210 return seq->file->f_cred->user_ns; 211 #else 212 extern struct user_namespace init_user_ns; 213 return &init_user_ns; 214 #endif 215 } 216 217 /** 218 * seq_show_options - display mount options with appropriate escapes. 219 * @m: the seq_file handle 220 * @name: the mount option name 221 * @value: the mount option name's value, can be NULL 222 */ 223 static inline void seq_show_option(struct seq_file *m, const char *name, 224 const char *value) 225 { 226 seq_putc(m, ','); 227 seq_escape(m, name, ",= \t\n\\"); 228 if (value) { 229 seq_putc(m, '='); 230 seq_escape(m, value, ", \t\n\\"); 231 } 232 } 233 234 /** 235 * seq_show_option_n - display mount options with appropriate escapes 236 * where @value must be a specific length. 237 * @m: the seq_file handle 238 * @name: the mount option name 239 * @value: the mount option name's value, cannot be NULL 240 * @length: the length of @value to display 241 * 242 * This is a macro since this uses "length" to define the size of the 243 * stack buffer. 244 */ 245 #define seq_show_option_n(m, name, value, length) { \ 246 char val_buf[length + 1]; \ 247 strncpy(val_buf, value, length); \ 248 val_buf[length] = '\0'; \ 249 seq_show_option(m, name, val_buf); \ 250 } 251 252 #define SEQ_START_TOKEN ((void *)1) 253 /* 254 * Helpers for iteration over list_head-s in seq_files 255 */ 256 257 extern struct list_head *seq_list_start(struct list_head *head, 258 loff_t pos); 259 extern struct list_head *seq_list_start_head(struct list_head *head, 260 loff_t pos); 261 extern struct list_head *seq_list_next(void *v, struct list_head *head, 262 loff_t *ppos); 263 264 /* 265 * Helpers for iteration over hlist_head-s in seq_files 266 */ 267 268 extern struct hlist_node *seq_hlist_start(struct hlist_head *head, 269 loff_t pos); 270 extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head, 271 loff_t pos); 272 extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head, 273 loff_t *ppos); 274 275 extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head, 276 loff_t pos); 277 extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head, 278 loff_t pos); 279 extern struct hlist_node *seq_hlist_next_rcu(void *v, 280 struct hlist_head *head, 281 loff_t *ppos); 282 283 /* Helpers for iterating over per-cpu hlist_head-s in seq_files */ 284 extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos); 285 286 extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos); 287 288 void seq_file_init(void); 289 #endif 290