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: stable/11/sys/compat/linuxkpi/common/include/linux/file.h 328653 2018-02-01 13:01:44Z hselasky $
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	cap_rights_t rights;
54	struct file *file;
55
56	/* lookup file pointer by file descriptor index */
57	if (fget_unlocked(curthread->td_proc->p_fd, fd,
58	    cap_rights_init(&rights), &file, NULL) != 0)
59		return (NULL);
60
61	/* check if file handle really belongs to us */
62	if (file->f_data == NULL ||
63	    file->f_ops != &linuxfileops) {
64		fdrop(file, curthread);
65		return (NULL);
66	}
67	return ((struct linux_file *)file->f_data);
68}
69
70extern void linux_file_free(struct linux_file *filp);
71
72static inline void
73fput(struct linux_file *filp)
74{
75	if (refcount_release(filp->_file == NULL ?
76	    &filp->f_count : &filp->_file->f_count)) {
77		linux_file_free(filp);
78	}
79}
80
81static inline unsigned int
82file_count(struct linux_file *filp)
83{
84	return (filp->_file == NULL ?
85	    filp->f_count : filp->_file->f_count);
86}
87
88static inline void
89put_unused_fd(unsigned int fd)
90{
91	cap_rights_t rights;
92	struct file *file;
93
94	if (fget_unlocked(curthread->td_proc->p_fd, fd,
95	    cap_rights_init(&rights), &file, NULL) != 0) {
96		return;
97	}
98	/*
99	 * NOTE: We should only get here when the "fd" has not been
100	 * installed, so no need to free the associated Linux file
101	 * structure.
102	 */
103	fdclose(curthread, file, fd);
104
105	/* drop extra reference */
106	fdrop(file, curthread);
107}
108
109static inline void
110fd_install(unsigned int fd, struct linux_file *filp)
111{
112	cap_rights_t rights;
113	struct file *file;
114
115	if (fget_unlocked(curthread->td_proc->p_fd, fd,
116	    cap_rights_init(&rights), &file, NULL) != 0) {
117		filp->_file = NULL;
118	} else {
119		filp->_file = file;
120		finit(file, filp->f_mode, DTYPE_DEV, filp, &linuxfileops);
121
122		/* transfer reference count from "filp" to "file" */
123		while (refcount_release(&filp->f_count) == 0)
124			refcount_acquire(&file->f_count);
125	}
126
127	/* drop the extra reference */
128	fput(filp);
129}
130
131static inline int
132get_unused_fd(void)
133{
134	struct file *file;
135	int error;
136	int fd;
137
138	error = falloc(curthread, &file, &fd, 0);
139	if (error)
140		return -error;
141	/* drop the extra reference */
142	fdrop(file, curthread);
143	return fd;
144}
145
146static inline int
147get_unused_fd_flags(int flags)
148{
149	struct file *file;
150	int error;
151	int fd;
152
153	error = falloc(curthread, &file, &fd, flags);
154	if (error)
155		return -error;
156	/* drop the extra reference */
157	fdrop(file, curthread);
158	return fd;
159}
160
161extern struct linux_file *linux_file_alloc(void);
162
163static inline struct linux_file *
164alloc_file(int mode, const struct file_operations *fops)
165{
166	struct linux_file *filp;
167
168	filp = linux_file_alloc();
169	filp->f_op = fops;
170	filp->f_mode = mode;
171
172	return (filp);
173}
174
175struct fd {
176	struct linux_file *linux_file;
177};
178
179static inline void fdput(struct fd fd)
180{
181	fput(fd.linux_file);
182}
183
184static inline struct fd fdget(unsigned int fd)
185{
186	struct linux_file *f = linux_fget(fd);
187	return (struct fd){f};
188}
189
190#define	file		linux_file
191#define	fget(...)	linux_fget(__VA_ARGS__)
192
193#endif	/* _LINUX_FILE_H_ */
194