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Anthony Liguori1da27382012-06-25 13:13:31 -05001/*
2 * QEMU Random Number Generator Backend
3 *
4 * Copyright IBM, Corp. 2012
5 *
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
8 *
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.
11 */
12
Peter Maydell9c058332016-01-29 17:49:54 +000013#include "qemu/osdep.h"
Paolo Bonzinidccfcd02013-04-08 16:55:25 +020014#include "sysemu/rng.h"
Marc-André Lureau4d43a602017-01-26 18:26:44 +040015#include "chardev/char-fe.h"
Markus Armbrusterda34e652016-03-14 09:01:28 +010016#include "qapi/error.h"
Paolo Bonzini7b1b5d12012-12-17 18:19:43 +010017#include "qapi/qmp/qerror.h"
Anthony Liguori1da27382012-06-25 13:13:31 -050018
19#define TYPE_RNG_EGD "rng-egd"
20#define RNG_EGD(obj) OBJECT_CHECK(RngEgd, (obj), TYPE_RNG_EGD)
21
22typedef struct RngEgd
23{
24 RngBackend parent;
25
Marc-André Lureau32a6ebe2016-10-22 12:52:52 +030026 CharBackend chr;
Anthony Liguori1da27382012-06-25 13:13:31 -050027 char *chr_name;
Anthony Liguori1da27382012-06-25 13:13:31 -050028} RngEgd;
29
Ladi Prosek60253ed2016-03-03 09:37:18 +010030static void rng_egd_request_entropy(RngBackend *b, RngRequest *req)
Anthony Liguori1da27382012-06-25 13:13:31 -050031{
32 RngEgd *s = RNG_EGD(b);
Ladi Prosek60253ed2016-03-03 09:37:18 +010033 size_t size = req->size;
Anthony Liguori1da27382012-06-25 13:13:31 -050034
35 while (size > 0) {
36 uint8_t header[2];
37 uint8_t len = MIN(size, 255);
38
39 /* synchronous entropy request */
40 header[0] = 0x02;
41 header[1] = len;
42
Daniel P. Berrange6ab3fc32016-09-06 14:56:04 +010043 /* XXX this blocks entire thread. Rewrite to use
44 * qemu_chr_fe_write and background I/O callbacks */
Marc-André Lureau5345fdb2016-10-22 12:52:55 +030045 qemu_chr_fe_write_all(&s->chr, header, sizeof(header));
Anthony Liguori1da27382012-06-25 13:13:31 -050046
47 size -= len;
48 }
Anthony Liguori1da27382012-06-25 13:13:31 -050049}
50
Anthony Liguori1da27382012-06-25 13:13:31 -050051static int rng_egd_chr_can_read(void *opaque)
52{
53 RngEgd *s = RNG_EGD(opaque);
Ladi Prosek443590c2016-03-03 14:16:11 +010054 RngRequest *req;
Anthony Liguori1da27382012-06-25 13:13:31 -050055 int size = 0;
56
Ladi Prosek443590c2016-03-03 14:16:11 +010057 QSIMPLEQ_FOREACH(req, &s->parent.requests, next) {
Anthony Liguori1da27382012-06-25 13:13:31 -050058 size += req->size - req->offset;
59 }
60
61 return size;
62}
63
64static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size)
65{
66 RngEgd *s = RNG_EGD(opaque);
Amos Kong1eb1bd92013-11-21 16:42:51 +080067 size_t buf_offset = 0;
Anthony Liguori1da27382012-06-25 13:13:31 -050068
Ladi Prosek443590c2016-03-03 14:16:11 +010069 while (size > 0 && !QSIMPLEQ_EMPTY(&s->parent.requests)) {
70 RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests);
Anthony Liguori1da27382012-06-25 13:13:31 -050071 int len = MIN(size, req->size - req->offset);
72
Amos Kong1eb1bd92013-11-21 16:42:51 +080073 memcpy(req->data + req->offset, buf + buf_offset, len);
74 buf_offset += len;
Anthony Liguori1da27382012-06-25 13:13:31 -050075 req->offset += len;
76 size -= len;
77
78 if (req->offset == req->size) {
Anthony Liguori1da27382012-06-25 13:13:31 -050079 req->receive_entropy(req->opaque, req->data, req->size);
80
Ladi Prosek9f14b0a2016-03-03 09:37:17 +010081 rng_backend_finalize_request(&s->parent, req);
Anthony Liguori1da27382012-06-25 13:13:31 -050082 }
83 }
84}
85
Anthony Liguori1da27382012-06-25 13:13:31 -050086static void rng_egd_opened(RngBackend *b, Error **errp)
87{
88 RngEgd *s = RNG_EGD(b);
Marc-André Lureau0ec7b3e2016-12-07 16:20:22 +030089 Chardev *chr;
Anthony Liguori1da27382012-06-25 13:13:31 -050090
91 if (s->chr_name == NULL) {
Markus Armbrusterc6bd8c72015-03-17 11:54:50 +010092 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
93 "chardev", "a valid character device");
Anthony Liguori1da27382012-06-25 13:13:31 -050094 return;
95 }
96
Marc-André Lureau32a6ebe2016-10-22 12:52:52 +030097 chr = qemu_chr_find(s->chr_name);
98 if (chr == NULL) {
Markus Armbruster75158eb2015-03-16 08:57:47 +010099 error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
100 "Device '%s' not found", s->chr_name);
Anthony Liguori1da27382012-06-25 13:13:31 -0500101 return;
102 }
Marc-André Lureau32a6ebe2016-10-22 12:52:52 +0300103 if (!qemu_chr_fe_init(&s->chr, chr, errp)) {
104 return;
105 }
Hans de Goede456d6062013-03-27 20:29:40 +0100106
Anthony Liguori1da27382012-06-25 13:13:31 -0500107 /* FIXME we should resubmit pending requests when the CDS reconnects. */
Marc-André Lureau5345fdb2016-10-22 12:52:55 +0300108 qemu_chr_fe_set_handlers(&s->chr, rng_egd_chr_can_read,
Anton Nefedov81517ba2017-07-06 15:08:49 +0300109 rng_egd_chr_read, NULL, NULL, s, NULL, true);
Anthony Liguori1da27382012-06-25 13:13:31 -0500110}
111
112static void rng_egd_set_chardev(Object *obj, const char *value, Error **errp)
113{
114 RngBackend *b = RNG_BACKEND(obj);
115 RngEgd *s = RNG_EGD(b);
116
117 if (b->opened) {
Markus Armbrusterc6bd8c72015-03-17 11:54:50 +0100118 error_setg(errp, QERR_PERMISSION_DENIED);
Anthony Liguori1da27382012-06-25 13:13:31 -0500119 } else {
Eduardo Habkostabb4d5f2014-09-04 19:10:47 +0300120 g_free(s->chr_name);
Anthony Liguori1da27382012-06-25 13:13:31 -0500121 s->chr_name = g_strdup(value);
122 }
123}
124
125static char *rng_egd_get_chardev(Object *obj, Error **errp)
126{
127 RngEgd *s = RNG_EGD(obj);
Marc-André Lureau0ec7b3e2016-12-07 16:20:22 +0300128 Chardev *chr = qemu_chr_fe_get_driver(&s->chr);
Anthony Liguori1da27382012-06-25 13:13:31 -0500129
Marc-André Lureau5345fdb2016-10-22 12:52:55 +0300130 if (chr && chr->label) {
131 return g_strdup(chr->label);
Anthony Liguori1da27382012-06-25 13:13:31 -0500132 }
133
134 return NULL;
135}
136
137static void rng_egd_init(Object *obj)
138{
139 object_property_add_str(obj, "chardev",
140 rng_egd_get_chardev, rng_egd_set_chardev,
141 NULL);
142}
143
144static void rng_egd_finalize(Object *obj)
145{
146 RngEgd *s = RNG_EGD(obj);
147
Marc-André Lureau1ce26102017-01-27 00:49:13 +0400148 qemu_chr_fe_deinit(&s->chr, false);
Anthony Liguori1da27382012-06-25 13:13:31 -0500149 g_free(s->chr_name);
Anthony Liguori1da27382012-06-25 13:13:31 -0500150}
151
152static void rng_egd_class_init(ObjectClass *klass, void *data)
153{
154 RngBackendClass *rbc = RNG_BACKEND_CLASS(klass);
155
156 rbc->request_entropy = rng_egd_request_entropy;
Anthony Liguori1da27382012-06-25 13:13:31 -0500157 rbc->opened = rng_egd_opened;
158}
159
Andreas Färber8c43a6f2013-01-10 16:19:07 +0100160static const TypeInfo rng_egd_info = {
Anthony Liguori1da27382012-06-25 13:13:31 -0500161 .name = TYPE_RNG_EGD,
162 .parent = TYPE_RNG_BACKEND,
163 .instance_size = sizeof(RngEgd),
164 .class_init = rng_egd_class_init,
165 .instance_init = rng_egd_init,
166 .instance_finalize = rng_egd_finalize,
167};
168
169static void register_types(void)
170{
171 type_register_static(&rng_egd_info);
172}
173
174type_init(register_types);