1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/* Hurdish implementation of getrandom
Copyright (C) 2016-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <hurd.h>
#include <sys/random.h>
#include <fcntl.h>
__libc_rwlock_define_initialized (static, lock);
static file_t random_server, random_server_nonblock,
urandom_server, urandom_server_nonblock;
extern char *__trivfs_server_name __attribute__((weak));
/* Write up to LENGTH bytes of randomness starting at BUFFER.
Return the number of bytes written, or -1 on error. */
ssize_t
__getrandom (void *buffer, size_t length, unsigned int flags)
{
const char *random_source = "/dev/urandom";
int open_flags = O_RDONLY;
file_t server, *cached_server;
error_t err;
char *data = buffer;
mach_msg_type_number_t nread = length;
switch (flags)
{
case 0:
cached_server = &urandom_server;
break;
case GRND_RANDOM:
cached_server = &random_server;
break;
case GRND_NONBLOCK:
cached_server = &urandom_server_nonblock;
break;
case GRND_RANDOM | GRND_NONBLOCK:
cached_server = &random_server_nonblock;
break;
default:
return __hurd_fail (EINVAL);
}
if (flags & GRND_RANDOM)
random_source = "/dev/random";
if (flags & GRND_NONBLOCK)
open_flags |= O_NONBLOCK;
/* No point in passing either O_NOCTTY, O_IGNORE_CTTY, or O_CLOEXEC
to file_name_lookup, since we're not making an fd. */
if (&__trivfs_server_name && __trivfs_server_name
&& __trivfs_server_name[0] == 'r'
&& __trivfs_server_name[1] == 'a'
&& __trivfs_server_name[2] == 'n'
&& __trivfs_server_name[3] == 'd'
&& __trivfs_server_name[4] == 'o'
&& __trivfs_server_name[5] == 'm'
&& __trivfs_server_name[6] == '\0')
/* We are random, don't try to read ourselves! */
return length;
again:
__libc_rwlock_rdlock (lock);
server = *cached_server;
if (MACH_PORT_VALID (server))
/* Attempt to read some random data using this port. */
err = __io_read (server, &data, &nread, -1, length);
else
err = MACH_SEND_INVALID_DEST;
__libc_rwlock_unlock (lock);
if (err == MACH_SEND_INVALID_DEST || err == MIG_SERVER_DIED)
{
file_t oldserver = server;
mach_port_urefs_t urefs;
/* Slow path: the cached port didn't work, or there was no
cached port in the first place. */
__libc_rwlock_wrlock (lock);
server = *cached_server;
if (server != oldserver)
{
/* Someone else must have refetched the port while we were
waiting for the lock. */
__libc_rwlock_unlock (lock);
goto again;
}
if (MACH_PORT_VALID (server))
{
/* It could be that someone else has refetched the port and
it got the very same name. So check whether it is a send
right (and not a dead name). */
err = __mach_port_get_refs (__mach_task_self (), server,
MACH_PORT_RIGHT_SEND, &urefs);
if (!err && urefs > 0)
{
__libc_rwlock_unlock (lock);
goto again;
}
/* Now we're sure that it's dead. */
__mach_port_deallocate (__mach_task_self (), server);
}
server = *cached_server = __file_name_lookup (random_source,
open_flags, 0);
__libc_rwlock_unlock (lock);
if (!MACH_PORT_VALID (server))
/* No luck. */
return -1;
goto again;
}
if (err)
return __hurd_fail (err);
if (data != buffer)
{
if (nread > length)
{
__vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
return __hurd_fail (EGRATUITOUS);
}
memcpy (buffer, data, nread);
__vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
}
return nread;
}
libc_hidden_def (__getrandom)
weak_alias (__getrandom, getrandom)
|
