[net-next-2.6.git] / fs / seq_file.c

/*
 * linux/fs/seq_file.c
 *
 * helper functions for making synthetic files from sequences of records.
 * initial implementation -- AV, Oct 2001.
 */

#include <linux/fs.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/slab.h>

#include <asm/uaccess.h>
#include <asm/page.h>

/**
 *	seq_open -	initialize sequential file
 *	@file: file we initialize
 *	@op: method table describing the sequence
 *
 *	seq_open() sets @file, associating it with a sequence described
 *	by @op.  @op->start() sets the iterator up and returns the first
 *	element of sequence. @op->stop() shuts it down.  @op->next()
 *	returns the next element of sequence.  @op->show() prints element
 *	into the buffer.  In case of error ->start() and ->next() return
 *	ERR_PTR(error).  In the end of sequence they return %NULL. ->show()
 *	returns 0 in case of success and negative number in case of error.
 *	Returning SEQ_SKIP means "discard this element and move on".
 */
int seq_open(struct file *file, const struct seq_operations *op)
{
	struct seq_file *p = file->private_data;

	if (!p) {
		p = kmalloc(sizeof(*p), GFP_KERNEL);
		if (!p)
			return -ENOMEM;
		file->private_data = p;
	}
	memset(p, 0, sizeof(*p));
	mutex_init(&p->lock);
	p->op = op;

	/*
	 * Wrappers around seq_open(e.g. swaps_open) need to be
	 * aware of this. If they set f_version themselves, they
	 * should call seq_open first and then set f_version.
	 */
	file->f_version = 0;

	/* SEQ files support lseek, but not pread/pwrite */
	file->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
	return 0;
}
EXPORT_SYMBOL(seq_open);

/**
 *	seq_read -	->read() method for sequential files.
 *	@file: the file to read from
 *	@buf: the buffer to read to
 *	@size: the maximum number of bytes to read
 *	@ppos: the current position in the file
 *
 *	Ready-made ->f_op->read()
 */
ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{
	struct seq_file *m = (struct seq_file *)file->private_data;
	size_t copied = 0;
	loff_t pos;
	size_t n;
	void *p;
	int err = 0;

	mutex_lock(&m->lock);
	/*
	 * seq_file->op->..m_start/m_stop/m_next may do special actions
	 * or optimisations based on the file->f_version, so we want to
	 * pass the file->f_version to those methods.
	 *
	 * seq_file->version is just copy of f_version, and seq_file
	 * methods can treat it simply as file version.
	 * It is copied in first and copied out after all operations.
	 * It is convenient to have it as  part of structure to avoid the
	 * need of passing another argument to all the seq_file methods.
	 */
	m->version = file->f_version;
	/* grab buffer if we didn't have one */
	if (!m->buf) {
		m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
		if (!m->buf)
			goto Enomem;
	}
	/* if not empty - flush it first */
	if (m->count) {
		n = min(m->count, size);
		err = copy_to_user(buf, m->buf + m->from, n);
		if (err)
			goto Efault;
		m->count -= n;
		m->from += n;
		size -= n;
		buf += n;
		copied += n;
		if (!m->count)
			m->index++;
		if (!size)
			goto Done;
	}
	/* we need at least one record in buffer */
	pos = m->index;
	p = m->op->start(m, &pos);
	while (1) {
		err = PTR_ERR(p);
		if (!p || IS_ERR(p))
			break;
		err = m->op->show(m, p);
		if (err < 0)
			break;
		if (unlikely(err))
			m->count = 0;
		if (unlikely(!m->count)) {
			p = m->op->next(m, p, &pos);
			m->index = pos;
			continue;
		}
		if (m->count < m->size)
			goto Fill;
		m->op->stop(m, p);
		kfree(m->buf);
		m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
		if (!m->buf)
			goto Enomem;
		m->count = 0;
		m->version = 0;
		pos = m->index;
		p = m->op->start(m, &pos);
	}
	m->op->stop(m, p);
	m->count = 0;
	goto Done;
Fill:
	/* they want more? let's try to get some more */
	while (m->count < size) {
		size_t offs = m->count;
		loff_t next = pos;
		p = m->op->next(m, p, &next);
		if (!p || IS_ERR(p)) {
			err = PTR_ERR(p);
			break;
		}
		err = m->op->show(m, p);
		if (m->count == m->size || err) {
			m->count = offs;
			if (likely(err <= 0))
				break;
		}
		pos = next;
	}
	m->op->stop(m, p);
	n = min(m->count, size);
	err = copy_to_user(buf, m->buf, n);
	if (err)
		goto Efault;
	copied += n;
	m->count -= n;
	if (m->count)
		m->from = n;
	else
		pos++;
	m->index = pos;
Done:
	if (!copied)
		copied = err;
	else
		*ppos += copied;
	file->f_version = m->version;
	mutex_unlock(&m->lock);
	return copied;
Enomem:
	err = -ENOMEM;
	goto Done;
Efault:
	err = -EFAULT;
	goto Done;
}
EXPORT_SYMBOL(seq_read);

static int traverse(struct seq_file *m, loff_t offset)
{
	loff_t pos = 0, index;
	int error = 0;
	void *p;

	m->version = 0;
	index = 0;
	m->count = m->from = 0;
	if (!offset) {
		m->index = index;
		return 0;
	}
	if (!m->buf) {
		m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
		if (!m->buf)
			return -ENOMEM;
	}
	p = m->op->start(m, &index);
	while (p) {
		error = PTR_ERR(p);
		if (IS_ERR(p))
			break;
		error = m->op->show(m, p);
		if (error < 0)
			break;
		if (unlikely(error)) {
			error = 0;
			m->count = 0;
		}
		if (m->count == m->size)
			goto Eoverflow;
		if (pos + m->count > offset) {
			m->from = offset - pos;
			m->count -= m->from;
			m->index = index;
			break;
		}
		pos += m->count;
		m->count = 0;
		if (pos == offset) {
			index++;
			m->index = index;
			break;
		}
		p = m->op->next(m, p, &index);
	}
	m->op->stop(m, p);
	return error;

Eoverflow:
	m->op->stop(m, p);
	kfree(m->buf);
	m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
	return !m->buf ? -ENOMEM : -EAGAIN;
}

/**
 *	seq_lseek -	->llseek() method for sequential files.
 *	@file: the file in question
 *	@offset: new position
 *	@origin: 0 for absolute, 1 for relative position
 *
 *	Ready-made ->f_op->llseek()
 */
loff_t seq_lseek(struct file *file, loff_t offset, int origin)
{
	struct seq_file *m = (struct seq_file *)file->private_data;
	loff_t retval = -EINVAL;

	mutex_lock(&m->lock);
	m->version = file->f_version;
	switch (origin) {
		case 1:
			offset += file->f_pos;
		case 0:
			if (offset < 0)
				break;
			retval = offset;
			if (offset != file->f_pos) {
				while ((retval=traverse(m, offset)) == -EAGAIN)
					;
				if (retval) {
					/* with extreme prejudice... */
					file->f_pos = 0;
					m->version = 0;
					m->index = 0;
					m->count = 0;
				} else {
					retval = file->f_pos = offset;
				}
			}
	}
	file->f_version = m->version;
	mutex_unlock(&m->lock);
	return retval;
}
EXPORT_SYMBOL(seq_lseek);

/**
 *	seq_release -	free the structures associated with sequential file.
 *	@file: file in question
 *	@inode: file->f_path.dentry->d_inode
 *
 *	Frees the structures associated with sequential file; can be used
 *	as ->f_op->release() if you don't have private data to destroy.
 */
int seq_release(struct inode *inode, struct file *file)
{
	struct seq_file *m = (struct seq_file *)file->private_data;
	kfree(m->buf);
	kfree(m);
	return 0;
}
EXPORT_SYMBOL(seq_release);

/**
 *	seq_escape -	print string into buffer, escaping some characters
 *	@m:	target buffer
 *	@s:	string
 *	@esc:	set of characters that need escaping
 *
 *	Puts string into buffer, replacing each occurrence of character from
 *	@esc with usual octal escape.  Returns 0 in case of success, -1 - in
 *	case of overflow.
 */
int seq_escape(struct seq_file *m, const char *s, const char *esc)
{
	char *end = m->buf + m->size;
        char *p;
	char c;

        for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) {
		if (!strchr(esc, c)) {
			*p++ = c;
			continue;
		}
		if (p + 3 < end) {
			*p++ = '\\';
			*p++ = '0' + ((c & 0300) >> 6);
			*p++ = '0' + ((c & 070) >> 3);
			*p++ = '0' + (c & 07);
			continue;
		}
		m->count = m->size;
		return -1;
        }
	m->count = p - m->buf;
        return 0;
}
EXPORT_SYMBOL(seq_escape);

int seq_printf(struct seq_file *m, const char *f, ...)
{
	va_list args;
	int len;

	if (m->count < m->size) {
		va_start(args, f);
		len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
		va_end(args);
		if (m->count + len < m->size) {
			m->count += len;
			return 0;
		}
	}
	m->count = m->size;
	return -1;
}
EXPORT_SYMBOL(seq_printf);

/**
 * 	mangle_path - mangle and copy path to buffer beginning
 * 	@s - buffer start
 * 	@p - beginning of path in above buffer
 *      @esc - set of characters that need escaping
 *
 *      Copy the path from @p to @s, replacing each occurrence of character from
 *      @esc with usual octal escape.
 *      Returns pointer past last written character in @s, or NULL in case of
 *      failure.
 */
char *mangle_path(char *s, char *p, char *esc)
{
	while (s <= p) {
		char c = *p++;
		if (!c) {
			return s;
		} else if (!strchr(esc, c)) {
			*s++ = c;
		} else if (s + 4 > p) {
			break;
		} else {
			*s++ = '\\';
			*s++ = '0' + ((c & 0300) >> 6);
			*s++ = '0' + ((c & 070) >> 3);
			*s++ = '0' + (c & 07);
		}
	}
	return NULL;
}
EXPORT_SYMBOL_GPL(mangle_path);

/*
 * return the absolute path of 'dentry' residing in mount 'mnt'.
 */
int seq_path(struct seq_file *m, struct path *path, char *esc)
{
	if (m->count < m->size) {
		char *s = m->buf + m->count;
		char *p = d_path(path, s, m->size - m->count);
		if (!IS_ERR(p)) {
			s = mangle_path(s, p, esc);
			if (s) {
				p = m->buf + m->count;
				m->count = s - m->buf;
				return s - p;
			}
		}
	}
	m->count = m->size;
	return -1;
}
EXPORT_SYMBOL(seq_path);

/*
 * Same as seq_path, but relative to supplied root.
 *
 * root may be changed, see __d_path().
 */
int seq_path_root(struct seq_file *m, struct path *path, struct path *root,
		  char *esc)
{
	int err = -ENAMETOOLONG;
	if (m->count < m->size) {
		char *s = m->buf + m->count;
		char *p;

		spin_lock(&dcache_lock);
		p = __d_path(path, root, s, m->size - m->count);
		spin_unlock(&dcache_lock);
		err = PTR_ERR(p);
		if (!IS_ERR(p)) {
			s = mangle_path(s, p, esc);
			if (s) {
				p = m->buf + m->count;
				m->count = s - m->buf;
				return 0;
			}
		}
	}
	m->count = m->size;
	return err;
}

/*
 * returns the path of the 'dentry' from the root of its filesystem.
 */
int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc)
{
	if (m->count < m->size) {
		char *s = m->buf + m->count;
		char *p = dentry_path(dentry, s, m->size - m->count);
		if (!IS_ERR(p)) {
			s = mangle_path(s, p, esc);
			if (s) {
				p = m->buf + m->count;
				m->count = s - m->buf;
				return s - p;
			}
		}
	}
	m->count = m->size;
	return -1;
}

int seq_bitmap(struct seq_file *m, unsigned long *bits, unsigned int nr_bits)
{
	if (m->count < m->size) {
		int len = bitmap_scnprintf(m->buf + m->count,
				m->size - m->count, bits, nr_bits);
		if (m->count + len < m->size) {
			m->count += len;
			return 0;
		}
	}
	m->count = m->size;
	return -1;
}
EXPORT_SYMBOL(seq_bitmap);

int seq_bitmap_list(struct seq_file *m, unsigned long *bits,
		unsigned int nr_bits)
{
	if (m->count < m->size) {
		int len = bitmap_scnlistprintf(m->buf + m->count,
				m->size - m->count, bits, nr_bits);
		if (m->count + len < m->size) {
			m->count += len;
			return 0;
		}
	}
	m->count = m->size;
	return -1;
}
EXPORT_SYMBOL(seq_bitmap_list);

static void *single_start(struct seq_file *p, loff_t *pos)
{
	return NULL + (*pos == 0);
}

static void *single_next(struct seq_file *p, void *v, loff_t *pos)
{
	++*pos;
	return NULL;
}

static void single_stop(struct seq_file *p, void *v)
{
}

int single_open(struct file *file, int (*show)(struct seq_file *, void *),
		void *data)
{
	struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL);
	int res = -ENOMEM;

	if (op) {
		op->start = single_start;
		op->next = single_next;
		op->stop = single_stop;
		op->show = show;
		res = seq_open(file, op);
		if (!res)
			((struct seq_file *)file->private_data)->private = data;
		else
			kfree(op);
	}
	return res;
}
EXPORT_SYMBOL(single_open);

int single_release(struct inode *inode, struct file *file)
{
	const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
	int res = seq_release(inode, file);
	kfree(op);
	return res;
}
EXPORT_SYMBOL(single_release);

int seq_release_private(struct inode *inode, struct file *file)
{
	struct seq_file *seq = file->private_data;

	kfree(seq->private);
	seq->private = NULL;
	return seq_release(inode, file);
}
EXPORT_SYMBOL(seq_release_private);

void *__seq_open_private(struct file *f, const struct seq_operations *ops,
		int psize)
{
	int rc;
	void *private;
	struct seq_file *seq;

	private = kzalloc(psize, GFP_KERNEL);
	if (private == NULL)
		goto out;

	rc = seq_open(f, ops);
	if (rc < 0)
		goto out_free;

	seq = f->private_data;
	seq->private = private;
	return private;

out_free:
	kfree(private);
out:
	return NULL;
}
EXPORT_SYMBOL(__seq_open_private);

int seq_open_private(struct file *filp, const struct seq_operations *ops,
		int psize)
{
	return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
}
EXPORT_SYMBOL(seq_open_private);

int seq_putc(struct seq_file *m, char c)
{
	if (m->count < m->size) {
		m->buf[m->count++] = c;
		return 0;
	}
	return -1;
}
EXPORT_SYMBOL(seq_putc);

int seq_puts(struct seq_file *m, const char *s)
{
	int len = strlen(s);
	if (m->count + len < m->size) {
		memcpy(m->buf + m->count, s, len);
		m->count += len;
		return 0;
	}
	m->count = m->size;
	return -1;
}
EXPORT_SYMBOL(seq_puts);

struct list_head *seq_list_start(struct list_head *head, loff_t pos)
{
	struct list_head *lh;

	list_for_each(lh, head)
		if (pos-- == 0)
			return lh;

	return NULL;
}

EXPORT_SYMBOL(seq_list_start);

struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
{
	if (!pos)
		return head;

	return seq_list_start(head, pos - 1);
}

EXPORT_SYMBOL(seq_list_start_head);

struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
{
	struct list_head *lh;

	lh = ((struct list_head *)v)->next;
	++*ppos;
	return lh == head ? NULL : lh;
}

EXPORT_SYMBOL(seq_list_next);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/seq_file.c
	3	*
	4	* helper functions for making synthetic files from sequences of records.
	5	* initial implementation -- AV, Oct 2001.
	6	*/
	7
	8	#include <linux/fs.h>
	9	#include <linux/module.h>
	10	#include <linux/seq_file.h>
	11	#include <linux/slab.h>
	12
	13	#include <asm/uaccess.h>
	14	#include <asm/page.h>
	15
	16	/**
	17	* seq_open - initialize sequential file
	18	* @file: file we initialize
	19	* @op: method table describing the sequence
	20	*
	21	* seq_open() sets @file, associating it with a sequence described
	22	* by @op. @op->start() sets the iterator up and returns the first
	23	* element of sequence. @op->stop() shuts it down. @op->next()
	24	* returns the next element of sequence. @op->show() prints element
	25	* into the buffer. In case of error ->start() and ->next() return
	26	* ERR_PTR(error). In the end of sequence they return %NULL. ->show()
	27	* returns 0 in case of success and negative number in case of error.
521b5d0c	28	* Returning SEQ_SKIP means "discard this element and move on".
1da177e4	29	*/
15ad7cdc	30	int seq_open(struct file file, const struct seq_operations op)
1da177e4	31	{
1abe77b0 AV	32	struct seq_file *p = file->private_data;
	33
	34	if (!p) {
	35	p = kmalloc(sizeof(*p), GFP_KERNEL);
	36	if (!p)
	37	return -ENOMEM;
	38	file->private_data = p;
	39	}
1da177e4	40	memset(p, 0, sizeof(*p));
0ac1759a	41	mutex_init(&p->lock);
1da177e4	42	p->op = op;
1da177e4 LT	43
	44	/*
	45	* Wrappers around seq_open(e.g. swaps_open) need to be
	46	* aware of this. If they set f_version themselves, they
	47	* should call seq_open first and then set f_version.
	48	*/
	49	file->f_version = 0;
	50
	51	/* SEQ files support lseek, but not pread/pwrite */
	52	file->f_mode &= ~(FMODE_PREAD \| FMODE_PWRITE);
	53	return 0;
	54	}
	55	EXPORT_SYMBOL(seq_open);
	56
	57	/**
	58	* seq_read - ->read() method for sequential files.
67be2dd1 MW	59	* @file: the file to read from
	60	* @buf: the buffer to read to
	61	* @size: the maximum number of bytes to read
	62	* @ppos: the current position in the file
1da177e4 LT	63	*
	64	* Ready-made ->f_op->read()
	65	*/
	66	ssize_t seq_read(struct file file, char __user buf, size_t size, loff_t *ppos)
	67	{
	68	struct seq_file m = (struct seq_file )file->private_data;
	69	size_t copied = 0;
	70	loff_t pos;
	71	size_t n;
	72	void *p;
	73	int err = 0;
	74
0ac1759a	75	mutex_lock(&m->lock);
1da177e4 LT	76	/*
	77	* seq_file->op->..m_start/m_stop/m_next may do special actions
	78	* or optimisations based on the file->f_version, so we want to
	79	* pass the file->f_version to those methods.
	80	*
	81	* seq_file->version is just copy of f_version, and seq_file
	82	* methods can treat it simply as file version.
	83	* It is copied in first and copied out after all operations.
	84	* It is convenient to have it as part of structure to avoid the
	85	* need of passing another argument to all the seq_file methods.
	86	*/
	87	m->version = file->f_version;
	88	/* grab buffer if we didn't have one */
	89	if (!m->buf) {
	90	m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
	91	if (!m->buf)
	92	goto Enomem;
	93	}
	94	/* if not empty - flush it first */
	95	if (m->count) {
	96	n = min(m->count, size);
	97	err = copy_to_user(buf, m->buf + m->from, n);
	98	if (err)
	99	goto Efault;
	100	m->count -= n;
	101	m->from += n;
	102	size -= n;
	103	buf += n;
	104	copied += n;
	105	if (!m->count)
	106	m->index++;
	107	if (!size)
	108	goto Done;
	109	}
	110	/* we need at least one record in buffer */
4cdfe84b AV	111	pos = m->index;
4cdfe84b AV	112	p = m->op->start(m, &pos);
1da177e4	113	while (1) {
1da177e4 LT	114	err = PTR_ERR(p);
	115	if (!p \|\| IS_ERR(p))
	116	break;
	117	err = m->op->show(m, p);
521b5d0c	118	if (err < 0)
1da177e4	119	break;
521b5d0c AV	120	if (unlikely(err))
521b5d0c AV	121	m->count = 0;
4cdfe84b AV	122	if (unlikely(!m->count)) {
	123	p = m->op->next(m, p, &pos);
	124	m->index = pos;
	125	continue;
	126	}
1da177e4 LT	127	if (m->count < m->size)
	128	goto Fill;
	129	m->op->stop(m, p);
	130	kfree(m->buf);
	131	m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
	132	if (!m->buf)
	133	goto Enomem;
	134	m->count = 0;
	135	m->version = 0;
4cdfe84b AV	136	pos = m->index;
4cdfe84b AV	137	p = m->op->start(m, &pos);
1da177e4 LT	138	}
	139	m->op->stop(m, p);
	140	m->count = 0;
	141	goto Done;
	142	Fill:
	143	/* they want more? let's try to get some more */
	144	while (m->count < size) {
	145	size_t offs = m->count;
	146	loff_t next = pos;
	147	p = m->op->next(m, p, &next);
	148	if (!p \|\| IS_ERR(p)) {
	149	err = PTR_ERR(p);
	150	break;
	151	}
	152	err = m->op->show(m, p);
521b5d0c	153	if (m->count == m->size \|\| err) {
1da177e4	154	m->count = offs;
521b5d0c AV	155	if (likely(err <= 0))
521b5d0c AV	156	break;
1da177e4 LT	157	}
	158	pos = next;
	159	}
	160	m->op->stop(m, p);
	161	n = min(m->count, size);
	162	err = copy_to_user(buf, m->buf, n);
	163	if (err)
	164	goto Efault;
	165	copied += n;
	166	m->count -= n;
	167	if (m->count)
	168	m->from = n;
	169	else
	170	pos++;
	171	m->index = pos;
	172	Done:
	173	if (!copied)
	174	copied = err;
	175	else
	176	*ppos += copied;
	177	file->f_version = m->version;
0ac1759a	178	mutex_unlock(&m->lock);
1da177e4 LT	179	return copied;
	180	Enomem:
	181	err = -ENOMEM;
	182	goto Done;
	183	Efault:
	184	err = -EFAULT;
	185	goto Done;
	186	}
	187	EXPORT_SYMBOL(seq_read);
	188
	189	static int traverse(struct seq_file *m, loff_t offset)
	190	{
cb510b81	191	loff_t pos = 0, index;
1da177e4 LT	192	int error = 0;
	193	void *p;
	194
	195	m->version = 0;
cb510b81	196	index = 0;
1da177e4	197	m->count = m->from = 0;
cb510b81 AD	198	if (!offset) {
cb510b81 AD	199	m->index = index;
1da177e4	200	return 0;
cb510b81	201	}
1da177e4 LT	202	if (!m->buf) {
	203	m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
	204	if (!m->buf)
	205	return -ENOMEM;
	206	}
cb510b81	207	p = m->op->start(m, &index);
1da177e4 LT	208	while (p) {
	209	error = PTR_ERR(p);
	210	if (IS_ERR(p))
	211	break;
	212	error = m->op->show(m, p);
521b5d0c	213	if (error < 0)
1da177e4	214	break;
521b5d0c AV	215	if (unlikely(error)) {
	216	error = 0;
	217	m->count = 0;
	218	}
1da177e4 LT	219	if (m->count == m->size)
	220	goto Eoverflow;
	221	if (pos + m->count > offset) {
	222	m->from = offset - pos;
	223	m->count -= m->from;
cb510b81	224	m->index = index;
1da177e4 LT	225	break;
	226	}
	227	pos += m->count;
	228	m->count = 0;
	229	if (pos == offset) {
cb510b81 AD	230	index++;
cb510b81 AD	231	m->index = index;
1da177e4 LT	232	break;
1da177e4 LT	233	}
cb510b81	234	p = m->op->next(m, p, &index);
1da177e4 LT	235	}
	236	m->op->stop(m, p);
	237	return error;
	238
	239	Eoverflow:
	240	m->op->stop(m, p);
	241	kfree(m->buf);
	242	m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
	243	return !m->buf ? -ENOMEM : -EAGAIN;
	244	}
	245
	246	/**
	247	* seq_lseek - ->llseek() method for sequential files.
67be2dd1 MW	248	* @file: the file in question
	249	* @offset: new position
	250	* @origin: 0 for absolute, 1 for relative position
1da177e4 LT	251	*
	252	* Ready-made ->f_op->llseek()
	253	*/
	254	loff_t seq_lseek(struct file *file, loff_t offset, int origin)
	255	{
	256	struct seq_file m = (struct seq_file )file->private_data;
16abef0e	257	loff_t retval = -EINVAL;
1da177e4	258
0ac1759a	259	mutex_lock(&m->lock);
1da177e4 LT	260	m->version = file->f_version;
	261	switch (origin) {
	262	case 1:
	263	offset += file->f_pos;
	264	case 0:
	265	if (offset < 0)
	266	break;
	267	retval = offset;
	268	if (offset != file->f_pos) {
	269	while ((retval=traverse(m, offset)) == -EAGAIN)
	270	;
	271	if (retval) {
	272	/* with extreme prejudice... */
	273	file->f_pos = 0;
	274	m->version = 0;
	275	m->index = 0;
	276	m->count = 0;
	277	} else {
	278	retval = file->f_pos = offset;
	279	}
	280	}
	281	}
1da177e4	282	file->f_version = m->version;
00c5746d	283	mutex_unlock(&m->lock);
1da177e4 LT	284	return retval;
	285	}
	286	EXPORT_SYMBOL(seq_lseek);
	287
	288	/**
	289	* seq_release - free the structures associated with sequential file.
	290	* @file: file in question
0f7fc9e4	291	* @inode: file->f_path.dentry->d_inode
1da177e4 LT	292	*
	293	* Frees the structures associated with sequential file; can be used
	294	* as ->f_op->release() if you don't have private data to destroy.
	295	*/
	296	int seq_release(struct inode inode, struct file file)
	297	{
	298	struct seq_file m = (struct seq_file )file->private_data;
	299	kfree(m->buf);
	300	kfree(m);
	301	return 0;
	302	}
	303	EXPORT_SYMBOL(seq_release);
	304
	305	/**
	306	* seq_escape - print string into buffer, escaping some characters
	307	* @m: target buffer
	308	* @s: string
	309	* @esc: set of characters that need escaping
	310	*
	311	* Puts string into buffer, replacing each occurrence of character from
	312	* @esc with usual octal escape. Returns 0 in case of success, -1 - in
	313	* case of overflow.
	314	*/
	315	int seq_escape(struct seq_file m, const char s, const char *esc)
	316	{
	317	char *end = m->buf + m->size;
	318	char *p;
	319	char c;
	320
	321	for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) {
	322	if (!strchr(esc, c)) {
	323	*p++ = c;
	324	continue;
	325	}
	326	if (p + 3 < end) {
	327	*p++ = '\\';
	328	*p++ = '0' + ((c & 0300) >> 6);
	329	*p++ = '0' + ((c & 070) >> 3);
	330	*p++ = '0' + (c & 07);
	331	continue;
	332	}
	333	m->count = m->size;
	334	return -1;
	335	}
	336	m->count = p - m->buf;
	337	return 0;
	338	}
	339	EXPORT_SYMBOL(seq_escape);
	340
	341	int seq_printf(struct seq_file m, const char f, ...)
	342	{
	343	va_list args;
	344	int len;
	345
	346	if (m->count < m->size) {
	347	va_start(args, f);
	348	len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
	349	va_end(args);
	350	if (m->count + len < m->size) {
	351	m->count += len;
	352	return 0;
	353	}
	354	}
	355	m->count = m->size;
356	return -1;
357	}
358	EXPORT_SYMBOL(seq_printf);
359
74e2f334 TE	360	/**
	361	* mangle_path - mangle and copy path to buffer beginning
	362	* @s - buffer start
	363	* @p - beginning of path in above buffer
	364	* @esc - set of characters that need escaping
	365	*
	366	* Copy the path from @p to @s, replacing each occurrence of character from
	367	* @esc with usual octal escape.
	368	* Returns pointer past last written character in @s, or NULL in case of
	369	* failure.
	370	*/
	371	char mangle_path(char s, char p, char esc)
6092d048 RP	372	{
	373	while (s <= p) {
	374	char c = *p++;
	375	if (!c) {
	376	return s;
	377	} else if (!strchr(esc, c)) {
	378	*s++ = c;
	379	} else if (s + 4 > p) {
	380	break;
	381	} else {
	382	*s++ = '\\';
	383	*s++ = '0' + ((c & 0300) >> 6);
	384	*s++ = '0' + ((c & 070) >> 3);
	385	*s++ = '0' + (c & 07);
	386	}
	387	}
	388	return NULL;
	389	}
74e2f334	390	EXPORT_SYMBOL_GPL(mangle_path);
6092d048 RP	391
	392	/*
	393	* return the absolute path of 'dentry' residing in mount 'mnt'.
	394	*/
c32c2f63	395	int seq_path(struct seq_file m, struct path path, char *esc)
1da177e4 LT	396	{
	397	if (m->count < m->size) {
	398	char *s = m->buf + m->count;
cf28b486	399	char *p = d_path(path, s, m->size - m->count);
1da177e4	400	if (!IS_ERR(p)) {
6092d048 RP	401	s = mangle_path(s, p, esc);
	402	if (s) {
	403	p = m->buf + m->count;
	404	m->count = s - m->buf;
	405	return s - p;
1da177e4 LT	406	}
	407	}
	408	}
	409	m->count = m->size;
	410	return -1;
	411	}
	412	EXPORT_SYMBOL(seq_path);
	413
9d1bc601 MS	414	/*
	415	* Same as seq_path, but relative to supplied root.
	416	*
	417	* root may be changed, see __d_path().
	418	*/
	419	int seq_path_root(struct seq_file m, struct path path, struct path *root,
	420	char *esc)
	421	{
	422	int err = -ENAMETOOLONG;
	423	if (m->count < m->size) {
	424	char *s = m->buf + m->count;
	425	char *p;
	426
	427	spin_lock(&dcache_lock);
	428	p = __d_path(path, root, s, m->size - m->count);
	429	spin_unlock(&dcache_lock);
	430	err = PTR_ERR(p);
	431	if (!IS_ERR(p)) {
	432	s = mangle_path(s, p, esc);
	433	if (s) {
	434	p = m->buf + m->count;
	435	m->count = s - m->buf;
	436	return 0;
	437	}
	438	}
	439	}
	440	m->count = m->size;
	441	return err;
	442	}
	443
6092d048 RP	444	/*
	445	* returns the path of the 'dentry' from the root of its filesystem.
	446	*/
	447	int seq_dentry(struct seq_file m, struct dentry dentry, char *esc)
	448	{
	449	if (m->count < m->size) {
	450	char *s = m->buf + m->count;
	451	char *p = dentry_path(dentry, s, m->size - m->count);
	452	if (!IS_ERR(p)) {
	453	s = mangle_path(s, p, esc);
	454	if (s) {
	455	p = m->buf + m->count;
	456	m->count = s - m->buf;
	457	return s - p;
	458	}
	459	}
	460	}
	461	m->count = m->size;
	462	return -1;
	463	}
	464
50ac2d69 AD	465	int seq_bitmap(struct seq_file m, unsigned long bits, unsigned int nr_bits)
50ac2d69 AD	466	{
85dd030e LJ	467	if (m->count < m->size) {
	468	int len = bitmap_scnprintf(m->buf + m->count,
	469	m->size - m->count, bits, nr_bits);
	470	if (m->count + len < m->size) {
	471	m->count += len;
	472	return 0;
	473	}
50ac2d69 AD	474	}
	475	m->count = m->size;
	476	return -1;
	477	}
85dd030e	478	EXPORT_SYMBOL(seq_bitmap);
50ac2d69	479
3eda2011 LJ	480	int seq_bitmap_list(struct seq_file m, unsigned long bits,
	481	unsigned int nr_bits)
	482	{
	483	if (m->count < m->size) {
	484	int len = bitmap_scnlistprintf(m->buf + m->count,
	485	m->size - m->count, bits, nr_bits);
	486	if (m->count + len < m->size) {
	487	m->count += len;
	488	return 0;
	489	}
	490	}
	491	m->count = m->size;
	492	return -1;
	493	}
	494	EXPORT_SYMBOL(seq_bitmap_list);
	495
1da177e4 LT	496	static void single_start(struct seq_file p, loff_t *pos)
	497	{
	498	return NULL + (*pos == 0);
	499	}
	500
	501	static void single_next(struct seq_file p, void v, loff_t pos)
	502	{
	503	++*pos;
	504	return NULL;
	505	}
	506
	507	static void single_stop(struct seq_file p, void v)
	508	{
	509	}
	510
	511	int single_open(struct file file, int (show)(struct seq_file , void ),
	512	void *data)
	513	{
	514	struct seq_operations op = kmalloc(sizeof(op), GFP_KERNEL);
	515	int res = -ENOMEM;
	516
	517	if (op) {
	518	op->start = single_start;
	519	op->next = single_next;
	520	op->stop = single_stop;
	521	op->show = show;
	522	res = seq_open(file, op);
	523	if (!res)
	524	((struct seq_file *)file->private_data)->private = data;
	525	else
	526	kfree(op);
	527	}
	528	return res;
	529	}
	530	EXPORT_SYMBOL(single_open);
	531
	532	int single_release(struct inode inode, struct file file)
	533	{
15ad7cdc	534	const struct seq_operations op = ((struct seq_file )file->private_data)->op;
1da177e4 LT	535	int res = seq_release(inode, file);
	536	kfree(op);
	537	return res;
	538	}
	539	EXPORT_SYMBOL(single_release);
	540
	541	int seq_release_private(struct inode inode, struct file file)
	542	{
	543	struct seq_file *seq = file->private_data;
	544
	545	kfree(seq->private);
	546	seq->private = NULL;
	547	return seq_release(inode, file);
	548	}
	549	EXPORT_SYMBOL(seq_release_private);
	550
39699037 PE	551	void __seq_open_private(struct file f, const struct seq_operations *ops,
	552	int psize)
	553	{
	554	int rc;
	555	void *private;
	556	struct seq_file *seq;
	557
	558	private = kzalloc(psize, GFP_KERNEL);
	559	if (private == NULL)
	560	goto out;
	561
	562	rc = seq_open(f, ops);
	563	if (rc < 0)
	564	goto out_free;
	565
	566	seq = f->private_data;
	567	seq->private = private;
	568	return private;
	569
	570	out_free:
	571	kfree(private);
	572	out:
	573	return NULL;
	574	}
	575	EXPORT_SYMBOL(__seq_open_private);
	576
	577	int seq_open_private(struct file filp, const struct seq_operations ops,
	578	int psize)
	579	{
	580	return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
	581	}
	582	EXPORT_SYMBOL(seq_open_private);
	583
1da177e4 LT	584	int seq_putc(struct seq_file *m, char c)
	585	{
	586	if (m->count < m->size) {
	587	m->buf[m->count++] = c;
	588	return 0;
	589	}
	590	return -1;
	591	}
	592	EXPORT_SYMBOL(seq_putc);
	593
	594	int seq_puts(struct seq_file m, const char s)
	595	{
	596	int len = strlen(s);
	597	if (m->count + len < m->size) {
	598	memcpy(m->buf + m->count, s, len);
	599	m->count += len;
	600	return 0;
	601	}
	602	m->count = m->size;
	603	return -1;
	604	}
	605	EXPORT_SYMBOL(seq_puts);
bcf67e16 PE	606
	607	struct list_head seq_list_start(struct list_head head, loff_t pos)
	608	{
	609	struct list_head *lh;
	610
	611	list_for_each(lh, head)
	612	if (pos-- == 0)
	613	return lh;
	614
	615	return NULL;
	616	}
	617
	618	EXPORT_SYMBOL(seq_list_start);
	619
	620	struct list_head seq_list_start_head(struct list_head head, loff_t pos)
	621	{
	622	if (!pos)
	623	return head;
	624
	625	return seq_list_start(head, pos - 1);
	626	}
	627
	628	EXPORT_SYMBOL(seq_list_start_head);
	629
	630	struct list_head seq_list_next(void v, struct list_head head, loff_t ppos)
	631	{
	632	struct list_head *lh;
	633
	634	lh = ((struct list_head *)v)->next;
	635	++*ppos;
	636	return lh == head ? NULL : lh;
	637	}
	638
	639	EXPORT_SYMBOL(seq_list_next);