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/qmp/qerror.h"
17 #include "hw/qdev.h" /* just for DEFINE_PROP_CHR */
19 #define TYPE_RNG_EGD "rng-egd"
20 #define RNG_EGD(obj) OBJECT_CHECK(RngEgd, (obj), TYPE_RNG_EGD)
32 typedef struct RngRequest
34 EntropyReceiveFunc
*receive_entropy
;
41 static void rng_egd_request_entropy(RngBackend
*b
, size_t size
,
42 EntropyReceiveFunc
*receive_entropy
,
45 RngEgd
*s
= RNG_EGD(b
);
48 req
= g_malloc(sizeof(*req
));
52 req
->receive_entropy
= receive_entropy
;
54 req
->data
= g_malloc(req
->size
);
58 uint8_t len
= MIN(size
, 255);
60 /* synchronous entropy request */
64 qemu_chr_fe_write(s
->chr
, header
, sizeof(header
));
69 s
->requests
= g_slist_append(s
->requests
, req
);
72 static void rng_egd_free_request(RngRequest
*req
)
78 static int rng_egd_chr_can_read(void *opaque
)
80 RngEgd
*s
= RNG_EGD(opaque
);
84 for (i
= s
->requests
; i
; i
= i
->next
) {
85 RngRequest
*req
= i
->data
;
86 size
+= req
->size
- req
->offset
;
92 static void rng_egd_chr_read(void *opaque
, const uint8_t *buf
, int size
)
94 RngEgd
*s
= RNG_EGD(opaque
);
95 size_t buf_offset
= 0;
97 while (size
> 0 && s
->requests
) {
98 RngRequest
*req
= s
->requests
->data
;
99 int len
= MIN(size
, req
->size
- req
->offset
);
101 memcpy(req
->data
+ req
->offset
, buf
+ buf_offset
, len
);
106 if (req
->offset
== req
->size
) {
107 s
->requests
= g_slist_remove_link(s
->requests
, s
->requests
);
109 req
->receive_entropy(req
->opaque
, req
->data
, req
->size
);
111 rng_egd_free_request(req
);
116 static void rng_egd_free_requests(RngEgd
*s
)
120 for (i
= s
->requests
; i
; i
= i
->next
) {
121 rng_egd_free_request(i
->data
);
124 g_slist_free(s
->requests
);
128 static void rng_egd_opened(RngBackend
*b
, Error
**errp
)
130 RngEgd
*s
= RNG_EGD(b
);
132 if (s
->chr_name
== NULL
) {
133 error_setg(errp
, QERR_INVALID_PARAMETER_VALUE
,
134 "chardev", "a valid character device");
138 s
->chr
= qemu_chr_find(s
->chr_name
);
139 if (s
->chr
== NULL
) {
140 error_set(errp
, ERROR_CLASS_DEVICE_NOT_FOUND
,
141 "Device '%s' not found", s
->chr_name
);
145 if (qemu_chr_fe_claim(s
->chr
) != 0) {
146 error_setg(errp
, QERR_DEVICE_IN_USE
, s
->chr_name
);
150 /* FIXME we should resubmit pending requests when the CDS reconnects. */
151 qemu_chr_add_handlers(s
->chr
, rng_egd_chr_can_read
, rng_egd_chr_read
,
155 static void rng_egd_set_chardev(Object
*obj
, const char *value
, Error
**errp
)
157 RngBackend
*b
= RNG_BACKEND(obj
);
158 RngEgd
*s
= RNG_EGD(b
);
161 error_setg(errp
, QERR_PERMISSION_DENIED
);
164 s
->chr_name
= g_strdup(value
);
168 static char *rng_egd_get_chardev(Object
*obj
, Error
**errp
)
170 RngEgd
*s
= RNG_EGD(obj
);
172 if (s
->chr
&& s
->chr
->label
) {
173 return g_strdup(s
->chr
->label
);
179 static void rng_egd_init(Object
*obj
)
181 object_property_add_str(obj
, "chardev",
182 rng_egd_get_chardev
, rng_egd_set_chardev
,
186 static void rng_egd_finalize(Object
*obj
)
188 RngEgd
*s
= RNG_EGD(obj
);
191 qemu_chr_add_handlers(s
->chr
, NULL
, NULL
, NULL
, NULL
);
192 qemu_chr_fe_release(s
->chr
);
197 rng_egd_free_requests(s
);
200 static void rng_egd_class_init(ObjectClass
*klass
, void *data
)
202 RngBackendClass
*rbc
= RNG_BACKEND_CLASS(klass
);
204 rbc
->request_entropy
= rng_egd_request_entropy
;
205 rbc
->opened
= rng_egd_opened
;
208 static const TypeInfo rng_egd_info
= {
209 .name
= TYPE_RNG_EGD
,
210 .parent
= TYPE_RNG_BACKEND
,
211 .instance_size
= sizeof(RngEgd
),
212 .class_init
= rng_egd_class_init
,
213 .instance_init
= rng_egd_init
,
214 .instance_finalize
= rng_egd_finalize
,
217 static void register_types(void)
219 type_register_static(&rng_egd_info
);
222 type_init(register_types
);