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
43 MALLOC_DEFINE(M_LSEQ, "seq_file", "seq_file");
44 
45 ssize_t
46 seq_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 
60 int
61 seq_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  */
71 off_t
72 seq_lseek(struct linux_file *file, off_t offset, int whence)
73 {
74 
75 	panic("%s not supported\n", __FUNCTION__);
76 	return (0);
77 }
78 
79 static void *
80 single_start(struct seq_file *p, off_t *pos)
81 {
82 
83 	return ((void *)(uintptr_t)(*pos == 0));
84 }
85 
86 static void *
87 single_next(struct seq_file *p, void *v, off_t *pos)
88 {
89 
90 	++*pos;
91 	return (NULL);
92 }
93 
94 static void
95 single_stop(struct seq_file *p, void *v)
96 {
97 }
98 
99 int
100 seq_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 
116 int
117 single_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 	}
135 	return (rc);
136 }
137 
138 int
139 seq_release(struct inode *inode __unused, struct linux_file *file)
140 {
141 	struct seq_file *m;
142 
143 	m = file->private_data;
144 	free(m, M_LSEQ);
145 	return (0);
146 }
147 
148 int
149 single_release(struct vnode *v, struct linux_file *f)
150 {
151 	const struct seq_operations *op = ((struct seq_file *)f->private_data)->op;
152 	int rc;
153 
154 	rc = seq_release(v, f);
155 	free(__DECONST(void *, op), M_LSEQ);
156 	return (rc);
157 }
158