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 u64 version; 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 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_SHOW_ATTRIBUTE(__name) \ 150 static int __name ## _open(struct inode *inode, struct file *file) \ 151 { \ 152 return single_open(file, __name ## _show, inode->i_private); \ 153 } \ 154 \ 155 static const struct file_operations __name ## _fops = { \ 156 .owner = THIS_MODULE, \ 157 .open = __name ## _open, \ 158 .read = seq_read, \ 159 .llseek = seq_lseek, \ 160 .release = single_release, \ 161 } 162 163 #define DEFINE_PROC_SHOW_ATTRIBUTE(__name) \ 164 static int __name ## _open(struct inode *inode, struct file *file) \ 165 { \ 166 return single_open(file, __name ## _show, inode->i_private); \ 167 } \ 168 \ 169 static const struct proc_ops __name ## _proc_ops = { \ 170 .proc_open = __name ## _open, \ 171 .proc_read = seq_read, \ 172 .proc_lseek = seq_lseek, \ 173 .proc_release = single_release, \ 174 } 175 176 static inline struct user_namespace *seq_user_ns(struct seq_file *seq) 177 { 178 #ifdef CONFIG_USER_NS 179 return seq->file->f_cred->user_ns; 180 #else 181 extern struct user_namespace init_user_ns; 182 return &init_user_ns; 183 #endif 184 } 185 186 /** 187 * seq_show_options - display mount options with appropriate escapes. 188 * @m: the seq_file handle 189 * @name: the mount option name 190 * @value: the mount option name's value, can be NULL 191 */ 192 static inline void seq_show_option(struct seq_file *m, const char *name, 193 const char *value) 194 { 195 seq_putc(m, ','); 196 seq_escape(m, name, ",= \t\n\\"); 197 if (value) { 198 seq_putc(m, '='); 199 seq_escape(m, value, ", \t\n\\"); 200 } 201 } 202 203 /** 204 * seq_show_option_n - display mount options with appropriate escapes 205 * where @value must be a specific length. 206 * @m: the seq_file handle 207 * @name: the mount option name 208 * @value: the mount option name's value, cannot be NULL 209 * @length: the length of @value to display 210 * 211 * This is a macro since this uses "length" to define the size of the 212 * stack buffer. 213 */ 214 #define seq_show_option_n(m, name, value, length) { \ 215 char val_buf[length + 1]; \ 216 strncpy(val_buf, value, length); \ 217 val_buf[length] = '\0'; \ 218 seq_show_option(m, name, val_buf); \ 219 } 220 221 #define SEQ_START_TOKEN ((void *)1) 222 /* 223 * Helpers for iteration over list_head-s in seq_files 224 */ 225 226 extern struct list_head *seq_list_start(struct list_head *head, 227 loff_t pos); 228 extern struct list_head *seq_list_start_head(struct list_head *head, 229 loff_t pos); 230 extern struct list_head *seq_list_next(void *v, struct list_head *head, 231 loff_t *ppos); 232 233 /* 234 * Helpers for iteration over hlist_head-s in seq_files 235 */ 236 237 extern struct hlist_node *seq_hlist_start(struct hlist_head *head, 238 loff_t pos); 239 extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head, 240 loff_t pos); 241 extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head, 242 loff_t *ppos); 243 244 extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head, 245 loff_t pos); 246 extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head, 247 loff_t pos); 248 extern struct hlist_node *seq_hlist_next_rcu(void *v, 249 struct hlist_head *head, 250 loff_t *ppos); 251 252 /* Helpers for iterating over per-cpu hlist_head-s in seq_files */ 253 extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos); 254 255 extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos); 256 257 void seq_file_init(void); 258 #endif 259