1 // SPDX-License-Identifier: GPL-2.0
6  * initial implementation -- AV, Oct 2001.
30 	m->count = m->size;  in seq_set_overflow()
42  *	seq_open -	initialize sequential file
47  *	by @op.  @op->start() sets the iterator up and returns the first
48  *	element of sequence. @op->stop() shuts it down.  @op->next()
49  *	returns the next element of sequence.  @op->show() prints element
50  *	into the buffer.  In case of error ->start() and ->next() return
51  *	ERR_PTR(error).  In the end of sequence they return %NULL. ->show()
55  *	pointer in @file->private_data. This pointer should not be modified.
61 	WARN_ON(file->private_data);  in seq_open()
65 		return -ENOMEM;  in seq_open()
67 	file->private_data = p;  in seq_open()
69 	mutex_init(&p->lock);  in seq_open()
70 	p->op = op;  in seq_open()
74 	p->file = file;  in seq_open()
85 	file->f_mode &= ~FMODE_PWRITE;  in seq_open()
96 	m->index = 0;  in traverse()
97 	m->count = m->from = 0;  in traverse()
101 	if (!m->buf) {  in traverse()
102 		m->buf = seq_buf_alloc(m->size = PAGE_SIZE);  in traverse()
103 		if (!m->buf)  in traverse()
104 			return -ENOMEM;  in traverse()
106 	p = m->op->start(m, &m->index);  in traverse()
111 		error = m->op->show(m, p);  in traverse()
116 			m->count = 0;  in traverse()
120 		p = m->op->next(m, p, &m->index);  in traverse()
121 		if (pos + m->count > offset) {  in traverse()
122 			m->from = offset - pos;  in traverse()
123 			m->count -= m->from;  in traverse()
126 		pos += m->count;  in traverse()
127 		m->count = 0;  in traverse()
131 	m->op->stop(m, p);  in traverse()
135 	m->op->stop(m, p);  in traverse()
136 	kvfree(m->buf);  in traverse()
137 	m->count = 0;  in traverse()
138 	m->buf = seq_buf_alloc(m->size <<= 1);  in traverse()
139 	return !m->buf ? -ENOMEM : -EAGAIN;  in traverse()
143  *	seq_read -	->read() method for sequential files.
149  *	Ready-made ->f_op->read()
169  * Ready-made ->f_op->read_iter()
173 	struct seq_file *m = iocb->ki_filp->private_data;  in seq_read_iter()
182 	mutex_lock(&m->lock);  in seq_read_iter()
188 	if (iocb->ki_pos == 0) {  in seq_read_iter()
189 		m->index = 0;  in seq_read_iter()
190 		m->count = 0;  in seq_read_iter()
194 	if (unlikely(iocb->ki_pos != m->read_pos)) {  in seq_read_iter()
195 		while ((err = traverse(m, iocb->ki_pos)) == -EAGAIN)  in seq_read_iter()
199 			m->read_pos = 0;  in seq_read_iter()
200 			m->index = 0;  in seq_read_iter()
201 			m->count = 0;  in seq_read_iter()
204 			m->read_pos = iocb->ki_pos;  in seq_read_iter()
209 	if (!m->buf) {  in seq_read_iter()
210 		m->buf = seq_buf_alloc(m->size = PAGE_SIZE);  in seq_read_iter()
211 		if (!m->buf)  in seq_read_iter()
214 	// something left in the buffer - copy it out first  in seq_read_iter()
215 	if (m->count) {  in seq_read_iter()
216 		n = copy_to_iter(m->buf + m->from, m->count, iter);  in seq_read_iter()
217 		m->count -= n;  in seq_read_iter()
218 		m->from += n;  in seq_read_iter()
220 		if (m->count)	// hadn't managed to copy everything  in seq_read_iter()
223 	// get a non-empty record in the buffer  in seq_read_iter()
224 	m->from = 0;  in seq_read_iter()
225 	p = m->op->start(m, &m->index);  in seq_read_iter()
230 		err = m->op->show(m, p);  in seq_read_iter()
233 		if (unlikely(err))	// ->show() says "skip it"  in seq_read_iter()
234 			m->count = 0;  in seq_read_iter()
235 		if (unlikely(!m->count)) { // empty record  in seq_read_iter()
236 			p = m->op->next(m, p, &m->index);  in seq_read_iter()
242 		m->op->stop(m, p);  in seq_read_iter()
243 		kvfree(m->buf);  in seq_read_iter()
244 		m->count = 0;  in seq_read_iter()
245 		m->buf = seq_buf_alloc(m->size <<= 1);  in seq_read_iter()
246 		if (!m->buf)  in seq_read_iter()
248 		p = m->op->start(m, &m->index);  in seq_read_iter()
251 	m->op->stop(m, p);  in seq_read_iter()
252 	m->count = 0;  in seq_read_iter()
255 	// one non-empty record is in the buffer; if they want more,  in seq_read_iter()
259 		size_t offs = m->count;  in seq_read_iter()
260 		loff_t pos = m->index;  in seq_read_iter()
262 		p = m->op->next(m, p, &m->index);  in seq_read_iter()
263 		if (pos == m->index) {  in seq_read_iter()
265 					    m->op->next);  in seq_read_iter()
266 			m->index++;  in seq_read_iter()
270 		if (m->count >= iov_iter_count(iter))  in seq_read_iter()
272 		err = m->op->show(m, p);  in seq_read_iter()
273 		if (err > 0) {		// ->show() says "skip it"  in seq_read_iter()
274 			m->count = offs;  in seq_read_iter()
276 			m->count = offs;  in seq_read_iter()
280 	m->op->stop(m, p);  in seq_read_iter()
281 	n = copy_to_iter(m->buf, m->count, iter);  in seq_read_iter()
283 	m->count -= n;  in seq_read_iter()
284 	m->from = n;  in seq_read_iter()
287 		copied = m->count ? -EFAULT : err;  in seq_read_iter()
289 		iocb->ki_pos += copied;  in seq_read_iter()
290 		m->read_pos += copied;  in seq_read_iter()
292 	mutex_unlock(&m->lock);  in seq_read_iter()
295 	err = -ENOMEM;  in seq_read_iter()
301  *	seq_lseek -	->llseek() method for sequential files.
306  *	Ready-made ->f_op->llseek()
310 	struct seq_file *m = file->private_data;  in seq_lseek()
311 	loff_t retval = -EINVAL;  in seq_lseek()
313 	mutex_lock(&m->lock);  in seq_lseek()
316 		offset += file->f_pos;  in seq_lseek()
322 		if (offset != m->read_pos) {  in seq_lseek()
323 			while ((retval = traverse(m, offset)) == -EAGAIN)  in seq_lseek()
327 				file->f_pos = 0;  in seq_lseek()
328 				m->read_pos = 0;  in seq_lseek()
329 				m->index = 0;  in seq_lseek()
330 				m->count = 0;  in seq_lseek()
332 				m->read_pos = offset;  in seq_lseek()
333 				retval = file->f_pos = offset;  in seq_lseek()
336 			file->f_pos = offset;  in seq_lseek()
339 	mutex_unlock(&m->lock);  in seq_lseek()
345  *	seq_release -	free the structures associated with sequential file.
350  *	as ->f_op->release() if you don't have private data to destroy.
354 	struct seq_file *m = file->private_data;  in seq_release()
355 	kvfree(m->buf);  in seq_release()
362  * seq_escape_mem - print data into buffer, escaping some characters
382 	seq_commit(m, ret < size ? ret : -1);  in seq_escape_mem()
390 	if (m->count < m->size) {  in seq_vprintf()
391 		len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);  in seq_vprintf()
392 		if (m->count + len < m->size) {  in seq_vprintf()
393 			m->count += len;  in seq_vprintf()
416 	if (m->count < m->size) {  in seq_bprintf()
417 		len = bstr_printf(m->buf + m->count, m->size - m->count, f,  in seq_bprintf()
419 		if (m->count + len < m->size) {  in seq_bprintf()
420 			m->count += len;  in seq_bprintf()
430  *	mangle_path -	mangle and copy path to buffer beginning
462  * seq_path - seq_file interface to print a pathname
474 	int res = -1;  in seq_path()
481 				res = end - buf;  in seq_path()
491  * seq_file_path - seq_file interface to print a pathname of a file
500 	return seq_path(m, &file->f_path, esc);  in seq_file_path()
512 	int res = -ENAMETOOLONG;  in seq_path_root()
524 				res = end - buf;  in seq_path_root()
526 				res = -ENAMETOOLONG;  in seq_path_root()
531 	return res < 0 && res != -ENAMETOOLONG ? res : 0;  in seq_path_root()
541 	int res = -1;  in seq_dentry()
548 				res = end - buf;  in seq_dentry()
576 	int res = -ENOMEM;  in single_open()
579 		op->start = single_start;  in single_open()
580 		op->next = single_next;  in single_open()
581 		op->stop = single_stop;  in single_open()
582 		op->show = show;  in single_open()
585 			((struct seq_file *)file->private_data)->private = data;  in single_open()
599 		return -ENOMEM;  in single_open_size()
605 	((struct seq_file *)file->private_data)->buf = buf;  in single_open_size()
606 	((struct seq_file *)file->private_data)->size = size;  in single_open_size()
613 	const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;  in single_release()
622 	struct seq_file *seq = file->private_data;  in seq_release_private()
624 	kfree(seq->private);  in seq_release_private()
625 	seq->private = NULL;  in seq_release_private()
645 	seq = f->private_data;  in __seq_open_private()
646 	seq->private = private;  in __seq_open_private()
659 	return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;  in seq_open_private()
665 	if (m->count >= m->size)  in seq_putc()
668 	m->buf[m->count++] = c;  in seq_putc()
676 	if (m->count + len >= m->size) {  in seq_puts()
680 	memcpy(m->buf + m->count, s, len);  in seq_puts()
681 	m->count += len;  in seq_puts()
686  * seq_put_decimal_ull_width - A helper routine for putting decimal numbers
692  * @width: a minimum field width
699 			 unsigned long long num, unsigned int width)  in seq_put_decimal_ull_width()  argument
703 	if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */  in seq_put_decimal_ull_width()
713 	if (!width)  in seq_put_decimal_ull_width()
714 		width = 1;  in seq_put_decimal_ull_width()
716 	if (m->count + width >= m->size)  in seq_put_decimal_ull_width()
719 	len = num_to_str(m->buf + m->count, m->size - m->count, num, width);  in seq_put_decimal_ull_width()
723 	m->count += len;  in seq_put_decimal_ull_width()
738  * seq_put_hex_ll - put a number in hexadecimal notation
742  * @width: a minimum field width
750 				unsigned long long v, unsigned int width)  in seq_put_hex_ll()  argument
766 		len = (sizeof(v) * 8 - __builtin_clzll(v) + 3) / 4;  in seq_put_hex_ll()
768 	if (len < width)  in seq_put_hex_ll()
769 		len = width;  in seq_put_hex_ll()
771 	if (m->count + len > m->size) {  in seq_put_hex_ll()
776 	for (i = len - 1; i >= 0; i--) {  in seq_put_hex_ll()
777 		m->buf[m->count + i] = hex_asc[0xf & v];  in seq_put_hex_ll()
780 	m->count += len;  in seq_put_hex_ll()
787 	if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */  in seq_put_decimal_ll()
797 	if (m->count + 2 >= m->size)  in seq_put_decimal_ll()
801 		m->buf[m->count++] = '-';  in seq_put_decimal_ll()
802 		num = -num;  in seq_put_decimal_ll()
806 		m->buf[m->count++] = num + '0';  in seq_put_decimal_ll()
810 	len = num_to_str(m->buf + m->count, m->size - m->count, num, 0);  in seq_put_decimal_ll()
814 	m->count += len;  in seq_put_decimal_ll()
823  * seq_write - write arbitrary data to buffer
828  * Return 0 on success, non-zero otherwise.
832 	if (seq->count + len < seq->size) {  in seq_write()
833 		memcpy(seq->buf + seq->count, data, len);  in seq_write()
834 		seq->count += len;  in seq_write()
838 	return -1;  in seq_write()
843  * seq_pad - write padding spaces to buffer
845  * @c: the byte to append after padding if non-zero
849 	int size = m->pad_until - m->count;  in seq_pad()
851 		if (size + m->count > m->size) {  in seq_pad()
855 		memset(m->buf + m->count, ' ', size);  in seq_pad()
856 		m->count += size;  in seq_pad()
879 		remaining -= rowsize;  in seq_hex_dump()
896 		seq_commit(m, ret < size ? ret : -1);  in seq_hex_dump()
908 		if (pos-- == 0)  in seq_list_start()
920 	return seq_list_start(head, pos - 1);  in seq_list_start_head()
928 	lh = ((struct list_head *)v)->next;  in seq_list_next()
939 		if (pos-- == 0)  in seq_list_start_rcu()
951 	return seq_list_start_rcu(head, pos - 1);  in seq_list_start_head_rcu()
967  * seq_hlist_start - start an iteration of a hlist
971  * Called at seq_file->op->start().
978 		if (pos-- == 0)  in seq_hlist_start()
985  * seq_hlist_start_head - start an iteration of a hlist
989  * Called at seq_file->op->start(). Call this function if you want to
997 	return seq_hlist_start(head, pos - 1);  in seq_hlist_start_head()
1002  * seq_hlist_next - move to the next position of the hlist
1007  * Called at seq_file->op->next().
1016 		return head->first;  in seq_hlist_next()
1018 		return node->next;  in seq_hlist_next()
1023  * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU
1027  * Called at seq_file->op->start().
1029  * This list-traversal primitive may safely run concurrently with
1030  * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1039 		if (pos-- == 0)  in seq_hlist_start_rcu()
1046  * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU
1050  * Called at seq_file->op->start(). Call this function if you want to
1053  * This list-traversal primitive may safely run concurrently with
1054  * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1063 	return seq_hlist_start_rcu(head, pos - 1);  in seq_hlist_start_head_rcu()
1068  * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU
1073  * Called at seq_file->op->next().
1075  * This list-traversal primitive may safely run concurrently with
1076  * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1087 		return rcu_dereference(head->first);  in seq_hlist_next_rcu()
1089 		return rcu_dereference(node->next);  in seq_hlist_next_rcu()
1094  * seq_hlist_start_percpu - start an iteration of a percpu hlist array
1099  * Called at seq_file->op->start().
1108 			if (pos-- == 0)  in seq_hlist_start_percpu()
1117  * seq_hlist_next_percpu - move to the next position of the percpu hlist array
1123  * Called at seq_file->op->next().
1133 	if (node->next)  in seq_hlist_next_percpu()
1134 		return node->next;  in seq_hlist_next_percpu()
1141 			return bucket->first;  in seq_hlist_next_percpu()