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Commit f8439806 authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Al Viro
Browse files

vfs: seq_file: add helpers for data filling 



Add two helpers that allow access to the seq_file's own buffer, but
hide the internal details of seq_files.

This allows easier implementation of special purpose filling
functions.  It also cleans up some existing functions which duplicated
the seq_file logic.

Make these inline functions in seq_file.h, as suggested by Al.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Acked-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent f9098980

fs/seq_file.c

+39 −36
Original line number Original line Diff line number Diff line
@@ -429,20 +429,21 @@ EXPORT_SYMBOL(mangle_path); 
 */

 */

int seq_path(struct seq_file *m, struct path *path, char *esc)

int seq_path(struct seq_file *m, struct path *path, char *esc)

{

{

	if (m->count < m->size) {

	char *buf;

		char *s = m->buf + m->count;

	size_t size = seq_get_buf(m, &buf);

		char *p = d_path(path, s, m->size - m->count);

	int res = -1;



	if (size) {

		char *p = d_path(path, buf, size);

		if (!IS_ERR(p)) {

		if (!IS_ERR(p)) {

			s = mangle_path(s, p, esc);

			char *end = mangle_path(buf, p, esc);

			if (s) {

			if (end)

				p = m->buf + m->count;

				res = end - buf;

				m->count = s - m->buf;

				return s - p;

			}

		}

		}

	}

	}

	m->count = m->size;

	seq_commit(m, res);

	return -1;



	return res;

}

}

EXPORT_SYMBOL(seq_path);

EXPORT_SYMBOL(seq_path);
@@ -454,27 +455,28 @@ EXPORT_SYMBOL(seq_path); 
int seq_path_root(struct seq_file *m, struct path *path, struct path *root,

int seq_path_root(struct seq_file *m, struct path *path, struct path *root,

		  char *esc)

		  char *esc)

{

{

	int err = -ENAMETOOLONG;

	char *buf;

	if (m->count < m->size) {

	size_t size = seq_get_buf(m, &buf);

		char *s = m->buf + m->count;

	int res = -ENAMETOOLONG;



	if (size) {

		char *p;

		char *p;





		spin_lock(&dcache_lock);

		spin_lock(&dcache_lock);

		p = __d_path(path, root, s, m->size - m->count);

		p = __d_path(path, root, buf, size);

		spin_unlock(&dcache_lock);

		spin_unlock(&dcache_lock);

		err = PTR_ERR(p);

		res = PTR_ERR(p);

		if (!IS_ERR(p)) {

		if (!IS_ERR(p)) {

			s = mangle_path(s, p, esc);

			char *end = mangle_path(buf, p, esc);

			if (s) {

			if (end)

				p = m->buf + m->count;

				res = end - buf;

				m->count = s - m->buf;

			else

				return 0;

				res = -ENAMETOOLONG;

			}

			err = -ENAMETOOLONG;

		}

		}

	}

	}

	m->count = m->size;

	seq_commit(m, res);

	return err;



	return res < 0 ? res : 0;

}

}





/*

/*
@@ -482,20 +484,21 @@ int seq_path_root(struct seq_file *m, struct path *path, struct path *root, 
 */

 */

int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc)

int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc)

{

{

	if (m->count < m->size) {

	char *buf;

		char *s = m->buf + m->count;

	size_t size = seq_get_buf(m, &buf);

		char *p = dentry_path(dentry, s, m->size - m->count);

	int res = -1;



	if (size) {

		char *p = dentry_path(dentry, buf, size);

		if (!IS_ERR(p)) {

		if (!IS_ERR(p)) {

			s = mangle_path(s, p, esc);

			char *end = mangle_path(buf, p, esc);

			if (s) {

			if (end)

				p = m->buf + m->count;

				res = end - buf;

				m->count = s - m->buf;

				return s - p;

		}

		}

	}

	}

	}

	seq_commit(m, res);

	m->count = m->size;



	return -1;

	return res;

}

}





int seq_bitmap(struct seq_file *m, const unsigned long *bits,

int seq_bitmap(struct seq_file *m, const unsigned long *bits,

include/linux/seq_file.h

+38 −0
Original line number Original line Diff line number Diff line
@@ -35,6 +35,44 @@ struct seq_operations { 




#define SEQ_SKIP 1

#define SEQ_SKIP 1





/**

 * seq_get_buf - get buffer to write arbitrary data to

 * @m: the seq_file handle

 * @bufp: the beginning of the buffer is stored here

 *

 * Return the number of bytes available in the buffer, or zero if

 * there's no space.

 */

static inline size_t seq_get_buf(struct seq_file *m, char **bufp)

{

	BUG_ON(m->count > m->size);

	if (m->count < m->size)

		*bufp = m->buf + m->count;

	else

		*bufp = NULL;



	return m->size - m->count;

}



/**

 * seq_commit - commit data to the buffer

 * @m: the seq_file handle

 * @num: the number of bytes to commit

 *

 * Commit @num bytes of data written to a buffer previously acquired

 * by seq_buf_get.  To signal an error condition, or that the data

 * didn't fit in the available space, pass a negative @num value.

 */

static inline void seq_commit(struct seq_file *m, int num)

{

	if (num < 0) {

		m->count = m->size;

	} else {

		BUG_ON(m->count + num > m->size);

		m->count += num;

	}

}



char *mangle_path(char *s, char *p, char *esc);

char *mangle_path(char *s, char *p, char *esc);

int seq_open(struct file *, const struct seq_operations *);

int seq_open(struct file *, const struct seq_operations *);

ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);

ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);