2 * QEMU Random Number Generator Backend
4 * Copyright IBM, Corp. 2012
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
13 #include "qemu/osdep.h"
14 #include "sysemu/rng.h"
15 #include "sysemu/char.h"
16 #include "qapi/error.h"
17 #include "qapi/qmp/qerror.h"
18 #include "hw/qdev.h" /* just for DEFINE_PROP_CHR */
20 #define TYPE_RNG_EGD "rng-egd"
21 #define RNG_EGD(obj) OBJECT_CHECK(RngEgd, (obj), TYPE_RNG_EGD)
31 static void rng_egd_request_entropy(RngBackend
*b
, RngRequest
*req
)
33 RngEgd
*s
= RNG_EGD(b
);
34 size_t size
= req
->size
;
38 uint8_t len
= MIN(size
, 255);
40 /* synchronous entropy request */
44 qemu_chr_fe_write(s
->chr
, header
, sizeof(header
));
50 static int rng_egd_chr_can_read(void *opaque
)
52 RngEgd
*s
= RNG_EGD(opaque
);
56 QSIMPLEQ_FOREACH(req
, &s
->parent
.requests
, next
) {
57 size
+= req
->size
- req
->offset
;
63 static void rng_egd_chr_read(void *opaque
, const uint8_t *buf
, int size
)
65 RngEgd
*s
= RNG_EGD(opaque
);
66 size_t buf_offset
= 0;
68 while (size
> 0 && !QSIMPLEQ_EMPTY(&s
->parent
.requests
)) {
69 RngRequest
*req
= QSIMPLEQ_FIRST(&s
->parent
.requests
);
70 int len
= MIN(size
, req
->size
- req
->offset
);
72 memcpy(req
->data
+ req
->offset
, buf
+ buf_offset
, len
);
77 if (req
->offset
== req
->size
) {
78 req
->receive_entropy(req
->opaque
, req
->data
, req
->size
);
80 rng_backend_finalize_request(&s
->parent
, req
);
85 static void rng_egd_opened(RngBackend
*b
, Error
**errp
)
87 RngEgd
*s
= RNG_EGD(b
);
89 if (s
->chr_name
== NULL
) {
90 error_setg(errp
, QERR_INVALID_PARAMETER_VALUE
,
91 "chardev", "a valid character device");
95 s
->chr
= qemu_chr_find(s
->chr_name
);
97 error_set(errp
, ERROR_CLASS_DEVICE_NOT_FOUND
,
98 "Device '%s' not found", s
->chr_name
);
102 if (qemu_chr_fe_claim(s
->chr
) != 0) {
103 error_setg(errp
, QERR_DEVICE_IN_USE
, s
->chr_name
);
107 /* FIXME we should resubmit pending requests when the CDS reconnects. */
108 qemu_chr_add_handlers(s
->chr
, rng_egd_chr_can_read
, rng_egd_chr_read
,
112 static void rng_egd_set_chardev(Object
*obj
, const char *value
, Error
**errp
)
114 RngBackend
*b
= RNG_BACKEND(obj
);
115 RngEgd
*s
= RNG_EGD(b
);
118 error_setg(errp
, QERR_PERMISSION_DENIED
);
121 s
->chr_name
= g_strdup(value
);
125 static char *rng_egd_get_chardev(Object
*obj
, Error
**errp
)
127 RngEgd
*s
= RNG_EGD(obj
);
129 if (s
->chr
&& s
->chr
->label
) {
130 return g_strdup(s
->chr
->label
);
136 static void rng_egd_init(Object
*obj
)
138 object_property_add_str(obj
, "chardev",
139 rng_egd_get_chardev
, rng_egd_set_chardev
,
143 static void rng_egd_finalize(Object
*obj
)
145 RngEgd
*s
= RNG_EGD(obj
);
148 qemu_chr_add_handlers(s
->chr
, NULL
, NULL
, NULL
, NULL
);
149 qemu_chr_fe_release(s
->chr
);
155 static void rng_egd_class_init(ObjectClass
*klass
, void *data
)
157 RngBackendClass
*rbc
= RNG_BACKEND_CLASS(klass
);
159 rbc
->request_entropy
= rng_egd_request_entropy
;
160 rbc
->opened
= rng_egd_opened
;
163 static const TypeInfo rng_egd_info
= {
164 .name
= TYPE_RNG_EGD
,
165 .parent
= TYPE_RNG_BACKEND
,
166 .instance_size
= sizeof(RngEgd
),
167 .class_init
= rng_egd_class_init
,
168 .instance_init
= rng_egd_init
,
169 .instance_finalize
= rng_egd_finalize
,
172 static void register_types(void)
174 type_register_static(&rng_egd_info
);
177 type_init(register_types
);