include/linux/seq_file.h

   1 #ifndef _LINUX_SEQ_FILE_H
   2 #define _LINUX_SEQ_FILE_H
   3
   4 #include <linux/types.h>
   5 #include <linux/string.h>
   6 #include <linux/bug.h>
   7 #include <linux/mutex.h>
   8 #include <linux/cpumask.h>
   9 #include <linux/nodemask.h>
  10
  11 struct seq_operations;
  12 struct file;
  13 struct path;
  14 struct inode;
  15 struct dentry;
  16 struct user_namespace;
  17
  18 struct seq_file {
  19         char *buf;
  20         size_t size;
  21         size_t from;
  22         size_t count;
  23         size_t pad_until;
  24         loff_t index;
  25         loff_t read_pos;
  26         u64 version;
  27         struct mutex lock;
  28         const struct seq_operations *op;
  29         int poll_event;
  30 #ifdef CONFIG_USER_NS
  31         struct user_namespace *user_ns;
  32 #endif
  33         void *private;
  34 };
  35
  36 struct seq_operations {
  37         void * (*start) (struct seq_file *m, loff_t *pos);
  38         void (*stop) (struct seq_file *m, void *v);
  39         void * (*next) (struct seq_file *m, void *v, loff_t *pos);
  40         int (*show) (struct seq_file *m, void *v);
  41 };
  42
  43 #define SEQ_SKIP 1
  44
  45 /**
  46  * seq_has_overflowed - check if the buffer has overflowed
  47  * @m: the seq_file handle
  48  *
  49  * seq_files have a buffer which may overflow. When this happens a larger
  50  * buffer is reallocated and all the data will be printed again.
  51  * The overflow state is true when m->count == m->size.
  52  *
  53  * Returns true if the buffer received more than it can hold.
  54  */
  55 static inline bool seq_has_overflowed(struct seq_file *m)
  56 {
  57         return m->count == m->size;
  58 }
  59
  60 /**
  61  * seq_get_buf - get buffer to write arbitrary data to
  62  * @m: the seq_file handle
  63  * @bufp: the beginning of the buffer is stored here
  64  *
  65  * Return the number of bytes available in the buffer, or zero if
  66  * there's no space.
  67  */
  68 static inline size_t seq_get_buf(struct seq_file *m, char **bufp)
  69 {
  70         BUG_ON(m->count > m->size);
  71         if (m->count < m->size)
  72                 *bufp = m->buf + m->count;
  73         else
  74                 *bufp = NULL;
  75
  76         return m->size - m->count;
  77 }
  78
  79 /**
  80  * seq_commit - commit data to the buffer
  81  * @m: the seq_file handle
  82  * @num: the number of bytes to commit
  83  *
  84  * Commit @num bytes of data written to a buffer previously acquired
  85  * by seq_buf_get.  To signal an error condition, or that the data
  86  * didn't fit in the available space, pass a negative @num value.
  87  */
  88 static inline void seq_commit(struct seq_file *m, int num)
  89 {
  90         if (num < 0) {
  91                 m->count = m->size;
  92         } else {
  93                 BUG_ON(m->count + num > m->size);
  94                 m->count += num;
  95         }
  96 }
  97
  98 /**
  99  * seq_setwidth - set padding width
 100  * @m: the seq_file handle
 101  * @size: the max number of bytes to pad.
 102  *
 103  * Call seq_setwidth() for setting max width, then call seq_printf() etc. and
 104  * finally call seq_pad() to pad the remaining bytes.
 105  */
 106 static inline void seq_setwidth(struct seq_file *m, size_t size)
 107 {
 108         m->pad_until = m->count + size;
 109 }
 110 void seq_pad(struct seq_file *m, char c);
 111
 112 char *mangle_path(char *s, const char *p, const char *esc);
 113 int seq_open(struct file *, const struct seq_operations *);
 114 ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);
 115 loff_t seq_lseek(struct file *, loff_t, int);
 116 int seq_release(struct inode *, struct file *);
 117 int seq_escape(struct seq_file *, const char *, const char *);
 118 int seq_putc(struct seq_file *m, char c);
 119 int seq_puts(struct seq_file *m, const char *s);
 120 int seq_write(struct seq_file *seq, const void *data, size_t len);
 121
 122 __printf(2, 3) int seq_printf(struct seq_file *, const char *, ...);
 123 __printf(2, 0) int seq_vprintf(struct seq_file *, const char *, va_list args);
 124
 125 int seq_path(struct seq_file *, const struct path *, const char *);
 126 int seq_file_path(struct seq_file *, struct file *, const char *);
 127 int seq_dentry(struct seq_file *, struct dentry *, const char *);
 128 int seq_path_root(struct seq_file *m, const struct path *path,
 129                   const struct path *root, const char *esc);
 130
 131 int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
 132 int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
 133 int single_release(struct inode *, struct file *);
 134 void *__seq_open_private(struct file *, const struct seq_operations *, int);
 135 int seq_open_private(struct file *, const struct seq_operations *, int);
 136 int seq_release_private(struct inode *, struct file *);
 137 int seq_put_decimal_ull(struct seq_file *m, char delimiter,
 138                         unsigned long long num);
 139 int seq_put_decimal_ll(struct seq_file *m, char delimiter,
 140                         long long num);
 141
 142 static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
 143 {
 144 #ifdef CONFIG_USER_NS
 145         return seq->user_ns;
 146 #else
 147         extern struct user_namespace init_user_ns;
 148         return &init_user_ns;
 149 #endif
 150 }
 151
 152 /**
 153  * seq_show_options - display mount options with appropriate escapes.
 154  * @m: the seq_file handle
 155  * @name: the mount option name
 156  * @value: the mount option name's value, can be NULL
 157  */
 158 static inline void seq_show_option(struct seq_file *m, const char *name,
 159                                    const char *value)
 160 {
 161         seq_putc(m, ',');
 162         seq_escape(m, name, ",= \t\n\\");
 163         if (value) {
 164                 seq_putc(m, '=');
 165                 seq_escape(m, value, ", \t\n\\");
 166         }
 167 }
 168
 169 /**
 170  * seq_show_option_n - display mount options with appropriate escapes
 171  *                     where @value must be a specific length.
 172  * @m: the seq_file handle
 173  * @name: the mount option name
 174  * @value: the mount option name's value, cannot be NULL
 175  * @length: the length of @value to display
 176  *
 177  * This is a macro since this uses "length" to define the size of the
 178  * stack buffer.
 179  */
 180 #define seq_show_option_n(m, name, value, length) {     \
 181         char val_buf[length + 1];                       \
 182         strncpy(val_buf, value, length);                \
 183         val_buf[length] = '\0';                         \
 184         seq_show_option(m, name, val_buf);              \
 185 }
 186
 187 #define SEQ_START_TOKEN ((void *)1)
 188 /*
 189  * Helpers for iteration over list_head-s in seq_files
 190  */
 191
 192 extern struct list_head *seq_list_start(struct list_head *head,
 193                 loff_t pos);
 194 extern struct list_head *seq_list_start_head(struct list_head *head,
 195                 loff_t pos);
 196 extern struct list_head *seq_list_next(void *v, struct list_head *head,
 197                 loff_t *ppos);
 198
 199 /*
 200  * Helpers for iteration over hlist_head-s in seq_files
 201  */
 202
 203 extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
 204                                           loff_t pos);
 205 extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
 206                                                loff_t pos);
 207 extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
 208                                          loff_t *ppos);
 209
 210 extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
 211                                               loff_t pos);
 212 extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
 213                                                    loff_t pos);
 214 extern struct hlist_node *seq_hlist_next_rcu(void *v,
 215                                                    struct hlist_head *head,
 216                                                    loff_t *ppos);
 217
 218 /* Helpers for iterating over per-cpu hlist_head-s in seq_files */
 219 extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
 220
 221 extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
 222
 223 #endif