seq_file.h

  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/nodemask.h>
 11#include <linux/fs.h>
 12#include <linux/cred.h>
 13
 14struct seq_operations;
 15
 16struct 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
 31struct 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 */
 50static 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 */
 63static 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 */
 83static 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 */
101static inline void seq_setwidth(struct seq_file *m, size_t size)
102{
103	m->pad_until = m->count + size;
104}
105void seq_pad(struct seq_file *m, char c);
106
107char *mangle_path(char *s, const char *p, const char *esc);
108int seq_open(struct file *, const struct seq_operations *);
109ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);
110ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter);
111loff_t seq_lseek(struct file *, loff_t, int);
112int seq_release(struct inode *, struct file *);
113int seq_write(struct seq_file *seq, const void *data, size_t len);
114
115__printf(2, 0)
116void seq_vprintf(struct seq_file *m, const char *fmt, va_list args);
117__printf(2, 3)
118void seq_printf(struct seq_file *m, const char *fmt, ...);
119void seq_putc(struct seq_file *m, char c);
120void __seq_puts(struct seq_file *m, const char *s);
121
122static __always_inline void seq_puts(struct seq_file *m, const char *s)
123{
124	if (!__builtin_constant_p(*s))
125		__seq_puts(m, s);
126	else if (s[0] && !s[1])
127		seq_putc(m, s[0]);
128	else
129		seq_write(m, s, __builtin_strlen(s));
130}
131
132void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
133			       unsigned long long num, unsigned int width);
134void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
135			 unsigned long long num);
136void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num);
137void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
138		    unsigned long long v, unsigned int width);
139
140void seq_escape_mem(struct seq_file *m, const char *src, size_t len,
141		    unsigned int flags, const char *esc);
142
143static inline void seq_escape_str(struct seq_file *m, const char *src,
144				  unsigned int flags, const char *esc)
145{
146	seq_escape_mem(m, src, strlen(src), flags, esc);
147}
148
149/**
150 * seq_escape - print string into buffer, escaping some characters
151 * @m: target buffer
152 * @s: NULL-terminated string
153 * @esc: set of characters that need escaping
154 *
155 * Puts string into buffer, replacing each occurrence of character from
156 * @esc with usual octal escape.
157 *
158 * Use seq_has_overflowed() to check for errors.
159 */
160static inline void seq_escape(struct seq_file *m, const char *s, const char *esc)
161{
162	seq_escape_str(m, s, ESCAPE_OCTAL, esc);
163}
164
165void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
166		  int rowsize, int groupsize, const void *buf, size_t len,
167		  bool ascii);
168
169int seq_path(struct seq_file *, const struct path *, const char *);
170int seq_file_path(struct seq_file *, struct file *, const char *);
171int seq_dentry(struct seq_file *, struct dentry *, const char *);
172int seq_path_root(struct seq_file *m, const struct path *path,
173		  const struct path *root, const char *esc);
174
175void *single_start(struct seq_file *, loff_t *);
176int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
177int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
178int single_release(struct inode *, struct file *);
179void *__seq_open_private(struct file *, const struct seq_operations *, int);
180int seq_open_private(struct file *, const struct seq_operations *, int);
181int seq_release_private(struct inode *, struct file *);
182
183#ifdef CONFIG_BINARY_PRINTF
184void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary);
185#endif
186
187#define DEFINE_SEQ_ATTRIBUTE(__name)					\
188static int __name ## _open(struct inode *inode, struct file *file)	\
189{									\
190	int ret = seq_open(file, &__name ## _sops);			\
191	if (!ret && inode->i_private) {					\
192		struct seq_file *seq_f = file->private_data;		\
193		seq_f->private = inode->i_private;			\
194	}								\
195	return ret;							\
196}									\
197									\
198static const struct file_operations __name ## _fops = {			\
199	.owner		= THIS_MODULE,					\
200	.open		= __name ## _open,				\
201	.read		= seq_read,					\
202	.llseek		= seq_lseek,					\
203	.release	= seq_release,					\
204}
205
206#define DEFINE_SHOW_ATTRIBUTE(__name)					\
207static int __name ## _open(struct inode *inode, struct file *file)	\
208{									\
209	return single_open(file, __name ## _show, inode->i_private);	\
210}									\
211									\
212static const struct file_operations __name ## _fops = {			\
213	.owner		= THIS_MODULE,					\
214	.open		= __name ## _open,				\
215	.read		= seq_read,					\
216	.llseek		= seq_lseek,					\
217	.release	= single_release,				\
218}
219
220#define DEFINE_SHOW_STORE_ATTRIBUTE(__name)				\
221static int __name ## _open(struct inode *inode, struct file *file)	\
222{									\
223	return single_open(file, __name ## _show, inode->i_private);	\
224}									\
225									\
226static const struct file_operations __name ## _fops = {			\
227	.owner		= THIS_MODULE,					\
228	.open		= __name ## _open,				\
229	.read		= seq_read,					\
230	.write		= __name ## _write,				\
231	.llseek		= seq_lseek,					\
232	.release	= single_release,				\
233}
234
235#define DEFINE_PROC_SHOW_ATTRIBUTE(__name)				\
236static int __name ## _open(struct inode *inode, struct file *file)	\
237{									\
238	return single_open(file, __name ## _show, pde_data(inode));	\
239}									\
240									\
241static const struct proc_ops __name ## _proc_ops = {			\
242	.proc_open	= __name ## _open,				\
243	.proc_read	= seq_read,					\
244	.proc_lseek	= seq_lseek,					\
245	.proc_release	= single_release,				\
246}
247
248static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
249{
250#ifdef CONFIG_USER_NS
251	return seq->file->f_cred->user_ns;
252#else
253	extern struct user_namespace init_user_ns;
254	return &init_user_ns;
255#endif
256}
257
258/**
259 * seq_show_options - display mount options with appropriate escapes.
260 * @m: the seq_file handle
261 * @name: the mount option name
262 * @value: the mount option name's value, can be NULL
263 */
264static inline void seq_show_option(struct seq_file *m, const char *name,
265				   const char *value)
266{
267	seq_putc(m, ',');
268	seq_escape(m, name, ",= \t\n\\");
269	if (value) {
270		seq_putc(m, '=');
271		seq_escape(m, value, ", \t\n\\");
272	}
273}
274
275/**
276 * seq_show_option_n - display mount options with appropriate escapes
277 *		       where @value must be a specific length (i.e.
278 *		       not NUL-terminated).
279 * @m: the seq_file handle
280 * @name: the mount option name
281 * @value: the mount option name's value, cannot be NULL
282 * @length: the exact length of @value to display, must be constant expression
283 *
284 * This is a macro since this uses "length" to define the size of the
285 * stack buffer.
286 */
287#define seq_show_option_n(m, name, value, length) {	\
288	char val_buf[length + 1];			\
289	memcpy(val_buf, value, length);			\
290	val_buf[length] = '\0';				\
291	seq_show_option(m, name, val_buf);		\
292}
293
294#define SEQ_START_TOKEN ((void *)1)
295/*
296 * Helpers for iteration over list_head-s in seq_files
297 */
298
299extern struct list_head *seq_list_start(struct list_head *head,
300		loff_t pos);
301extern struct list_head *seq_list_start_head(struct list_head *head,
302		loff_t pos);
303extern struct list_head *seq_list_next(void *v, struct list_head *head,
304		loff_t *ppos);
305
306extern struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos);
307extern struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos);
308extern struct list_head *seq_list_next_rcu(void *v, struct list_head *head, loff_t *ppos);
309
310/*
311 * Helpers for iteration over hlist_head-s in seq_files
312 */
313
314extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
315					  loff_t pos);
316extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
317					       loff_t pos);
318extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
319					 loff_t *ppos);
320
321extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
322					      loff_t pos);
323extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
324						   loff_t pos);
325extern struct hlist_node *seq_hlist_next_rcu(void *v,
326						   struct hlist_head *head,
327						   loff_t *ppos);
328
329/* Helpers for iterating over per-cpu hlist_head-s in seq_files */
330extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
331
332extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
333
334void seq_file_init(void);
335#endif