1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2018 Conrad Meyer <cem@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #include <sys/param.h>
33 #include <sys/errno.h>
34 #include <sys/limits.h>
35 #include <sys/proc.h>
36 #include <sys/random.h>
37 #include <sys/sysproto.h>
38 #include <sys/systm.h>
39 #include <sys/uio.h>
40
41 #define GRND_VALIDFLAGS (GRND_NONBLOCK | GRND_RANDOM)
42
43 /*
44 * random_read_uio(9) returns EWOULDBLOCK if a nonblocking request would block,
45 * but the Linux API name is EAGAIN. On FreeBSD, they have the same numeric
46 * value for now.
47 */
48 CTASSERT(EWOULDBLOCK == EAGAIN);
49
50 static int
51 kern_getrandom(struct thread *td, void *user_buf, size_t buflen,
52 unsigned int flags)
53 {
54 struct uio auio;
55 struct iovec aiov;
56 int error;
57
58 if ((flags & ~GRND_VALIDFLAGS) != 0)
59 return (EINVAL);
60 if (buflen > IOSIZE_MAX)
61 return (EINVAL);
62
63 if (buflen == 0) {
64 td->td_retval[0] = 0;
65 return (0);
66 }
67
68 aiov.iov_base = user_buf;
69 aiov.iov_len = buflen;
70 auio.uio_iov = &aiov;
71 auio.uio_iovcnt = 1;
72 auio.uio_offset = 0;
73 auio.uio_resid = buflen;
74 auio.uio_segflg = UIO_USERSPACE;
75 auio.uio_rw = UIO_READ;
76 auio.uio_td = td;
77
78 error = read_random_uio(&auio, (flags & GRND_NONBLOCK) != 0);
79 if (error == 0)
80 td->td_retval[0] = buflen - auio.uio_resid;
81 return (error);
82 }
83
84 #ifndef _SYS_SYSPROTO_H_
85 struct getrandom_args {
86 void *buf;
87 size_t buflen;
88 unsigned int flags;
89 };
90 #endif
91
92 int
93 sys_getrandom(struct thread *td, struct getrandom_args *uap)
94 {
95 return (kern_getrandom(td, uap->buf, uap->buflen, uap->flags));
96 }
Cache object: c0dd97c3524a2e8af64d77788b34eb22
|