1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice unmodified, this list of conditions, and the following
13 *    disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31#ifndef	_LINUX_FILE_H_
32#define	_LINUX_FILE_H_
33
34#include <sys/param.h>
35#include <sys/file.h>
36#include <sys/filedesc.h>
37#include <sys/refcount.h>
38#include <sys/capsicum.h>
39#include <sys/proc.h>
40
41#include <linux/fs.h>
42#include <linux/slab.h>
43
44struct linux_file;
45
46#undef file
47
48extern struct fileops linuxfileops;
49
50static inline struct linux_file *
51linux_fget(unsigned int fd)
52{
53	struct file *file;
54
55	/* lookup file pointer by file descriptor index */
56	if (fget_unlocked(curthread->td_proc->p_fd, fd,
57	    &cap_no_rights, &file) != 0)
58		return (NULL);
59
60	/* check if file handle really belongs to us */
61	if (file->f_data == NULL ||
62	    file->f_ops != &linuxfileops) {
63		fdrop(file, curthread);
64		return (NULL);
65	}
66	return ((struct linux_file *)file->f_data);
67}
68
69extern void linux_file_free(struct linux_file *filp);
70
71static inline void
72fput(struct linux_file *filp)
73{
74	if (refcount_release(filp->_file == NULL ?
75	    &filp->f_count : &filp->_file->f_count)) {
76		linux_file_free(filp);
77	}
78}
79
80static inline unsigned int
81file_count(struct linux_file *filp)
82{
83	return (filp->_file == NULL ?
84	    filp->f_count : filp->_file->f_count);
85}
86
87static inline void
88put_unused_fd(unsigned int fd)
89{
90	struct file *file;
91
92	if (fget_unlocked(curthread->td_proc->p_fd, fd,
93	    &cap_no_rights, &file) != 0) {
94		return;
95	}
96	/*
97	 * NOTE: We should only get here when the "fd" has not been
98	 * installed, so no need to free the associated Linux file
99	 * structure.
100	 */
101	fdclose(curthread, file, fd);
102
103	/* drop extra reference */
104	fdrop(file, curthread);
105}
106
107static inline void
108fd_install(unsigned int fd, struct linux_file *filp)
109{
110	struct file *file;
111
112	if (fget_unlocked(curthread->td_proc->p_fd, fd,
113	    &cap_no_rights, &file) != 0) {
114		filp->_file = NULL;
115	} else {
116		filp->_file = file;
117		finit(file, filp->f_mode, DTYPE_DEV, filp, &linuxfileops);
118
119		/* transfer reference count from "filp" to "file" */
120		while (refcount_release(&filp->f_count) == 0)
121			refcount_acquire(&file->f_count);
122	}
123
124	/* drop the extra reference */
125	fput(filp);
126}
127
128static inline int
129get_unused_fd(void)
130{
131	struct file *file;
132	int error;
133	int fd;
134
135	error = falloc(curthread, &file, &fd, 0);
136	if (error)
137		return -error;
138	/* drop the extra reference */
139	fdrop(file, curthread);
140	return fd;
141}
142
143static inline int
144get_unused_fd_flags(int flags)
145{
146	struct file *file;
147	int error;
148	int fd;
149
150	error = falloc(curthread, &file, &fd, flags);
151	if (error)
152		return -error;
153	/* drop the extra reference */
154	fdrop(file, curthread);
155	return fd;
156}
157
158extern struct linux_file *linux_file_alloc(void);
159
160static inline struct linux_file *
161alloc_file(int mode, const struct file_operations *fops)
162{
163	struct linux_file *filp;
164
165	filp = linux_file_alloc();
166	filp->f_op = fops;
167	filp->f_mode = mode;
168
169	return (filp);
170}
171
172struct fd {
173	struct linux_file *linux_file;
174};
175
176static inline void fdput(struct fd fd)
177{
178	fput(fd.linux_file);
179}
180
181static inline struct fd fdget(unsigned int fd)
182{
183	struct linux_file *f = linux_fget(fd);
184	return (struct fd){f};
185}
186
187#define	file		linux_file
188#define	fget(...)	linux_fget(__VA_ARGS__)
189
190#endif	/* _LINUX_FILE_H_ */
191