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);