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Commit 839cc2a9 authored by Tetsuo Handa's avatar Tetsuo Handa Committed by Linus Torvalds
Browse files

seq_file: introduce seq_setwidth() and seq_pad() 



There are several users who want to know bytes written by seq_*() for
alignment purpose.  Currently they are using %n format for knowing it
because seq_*() returns 0 on success.

This patch introduces seq_setwidth() and seq_pad() for allowing them to
align without using %n format.

Signed-off-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Cc: Joe Perches <joe@perches.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 57f4257e

fs/seq_file.c

+15 −0
Original line number Diff line number Diff line
@@ -766,6 +766,21 @@ int seq_write(struct seq_file *seq, const void *data, size_t len) 
}

EXPORT_SYMBOL(seq_write);



/**

 * seq_pad - write padding spaces to buffer

 * @m: seq_file identifying the buffer to which data should be written

 * @c: the byte to append after padding if non-zero

 */

void seq_pad(struct seq_file *m, char c)

{

	int size = m->pad_until - m->count;

	if (size > 0)

		seq_printf(m, "%*s", size, "");

	if (c)

		seq_putc(m, c);

}

EXPORT_SYMBOL(seq_pad);



struct list_head *seq_list_start(struct list_head *head, loff_t pos)

{

	struct list_head *lh;

include/linux/seq_file.h

+15 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ struct seq_file { 
	size_t size;

	size_t from;

	size_t count;

	size_t pad_until;

	loff_t index;

	loff_t read_pos;

	u64 version;
@@ -79,6 +80,20 @@ static inline void seq_commit(struct seq_file *m, int num) 
	}

}



/**

 * seq_setwidth - set padding width

 * @m: the seq_file handle

 * @size: the max number of bytes to pad.

 *

 * Call seq_setwidth() for setting max width, then call seq_printf() etc. and

 * finally call seq_pad() to pad the remaining bytes.

 */

static inline void seq_setwidth(struct seq_file *m, size_t size)

{

	m->pad_until = m->count + size;

}

void seq_pad(struct seq_file *m, char c);



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

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

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