1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2016-2018, Matthew Macy <mmacy@freebsd.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/types.h>
33#include <sys/systm.h>
34#include <sys/param.h>
35#include <sys/sbuf.h>
36#include <sys/syslog.h>
37#include <sys/vnode.h>
38
39#include <linux/seq_file.h>
40#include <linux/file.h>
41
42#undef file
43MALLOC_DEFINE(M_LSEQ, "seq_file", "seq_file");
44
45ssize_t
46seq_read(struct linux_file *f, char *ubuf, size_t size, off_t *ppos)
47{
48	struct seq_file *m = f->private_data;
49	void *p;
50	int rc;
51	off_t pos = 0;
52
53	p = m->op->start(m, &pos);
54	rc = m->op->show(m, p);
55	if (rc)
56		return (rc);
57	return (size);
58}
59
60int
61seq_write(struct seq_file *seq, const void *data, size_t len)
62{
63
64	return (sbuf_bcpy(seq->buf, data, len));
65}
66
67/*
68 * This only needs to be a valid address for lkpi
69 * drivers it should never actually be called
70 */
71off_t
72seq_lseek(struct linux_file *file, off_t offset, int whence)
73{
74
75	panic("%s not supported\n", __FUNCTION__);
76	return (0);
77}
78
79static void *
80single_start(struct seq_file *p, off_t *pos)
81{
82
83	return ((void *)(uintptr_t)(*pos == 0));
84}
85
86static void *
87single_next(struct seq_file *p, void *v, off_t *pos)
88{
89
90	++*pos;
91	return (NULL);
92}
93
94static void
95single_stop(struct seq_file *p, void *v)
96{
97}
98
99int
100seq_open(struct linux_file *f, const struct seq_operations *op)
101{
102	struct seq_file *p;
103
104	if (f->private_data != NULL)
105		log(LOG_WARNING, "%s private_data not NULL", __func__);
106
107	if ((p = malloc(sizeof(*p), M_LSEQ, M_NOWAIT|M_ZERO)) == NULL)
108		return (-ENOMEM);
109
110	f->private_data = p;
111	p->op = op;
112	p->file = f;
113	return (0);
114}
115
116int
117single_open(struct linux_file *f, int (*show)(struct seq_file *, void *), void *d)
118{
119	struct seq_operations *op;
120	int rc = -ENOMEM;
121
122	op = malloc(sizeof(*op), M_LSEQ, M_NOWAIT);
123	if (op) {
124		op->start = single_start;
125		op->next = single_next;
126		op->stop = single_stop;
127		op->show = show;
128		rc = seq_open(f, op);
129		if (rc)
130			free(op, M_LSEQ);
131		else
132			((struct seq_file *)f->private_data)->private = d;
133	}
134	return (rc);
135}
136
137int
138seq_release(struct inode *inode __unused, struct linux_file *file)
139{
140	struct seq_file *m;
141
142	m = file->private_data;
143	free(m, M_LSEQ);
144	return (0);
145}
146
147int
148single_release(struct vnode *v, struct linux_file *f)
149{
150	const struct seq_operations *op = ((struct seq_file *)f->private_data)->op;
151	int rc;
152
153	rc = seq_release(v, f);
154	free(__DECONST(void *, op), M_LSEQ);
155	return (rc);
156}
157