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(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, inode->i_private); \ 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 } 194 195 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 */ 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