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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"
Markus Armbruster0b8fa322019-05-23 16:35:07 +020018#include "qemu/module.h"
Anthony Liguori1da27382012-06-25 13:13:31 -050019
20#define TYPE_RNG_EGD "rng-egd"
21#define RNG_EGD(obj) OBJECT_CHECK(RngEgd, (obj), TYPE_RNG_EGD)
22
23typedef struct RngEgd
24{
25 RngBackend parent;
26
Marc-André Lureau32a6ebe2016-10-22 12:52:52 +030027 CharBackend chr;
Anthony Liguori1da27382012-06-25 13:13:31 -050028 char *chr_name;
Anthony Liguori1da27382012-06-25 13:13:31 -050029} RngEgd;
30
Ladi Prosek60253ed2016-03-03 09:37:18 +010031static void rng_egd_request_entropy(RngBackend *b, RngRequest *req)
Anthony Liguori1da27382012-06-25 13:13:31 -050032{
33 RngEgd *s = RNG_EGD(b);
Ladi Prosek60253ed2016-03-03 09:37:18 +010034 size_t size = req->size;
Anthony Liguori1da27382012-06-25 13:13:31 -050035
36 while (size > 0) {
37 uint8_t header[2];
38 uint8_t len = MIN(size, 255);
39
40 /* synchronous entropy request */
41 header[0] = 0x02;
42 header[1] = len;
43
Daniel P. Berrange6ab3fc32016-09-06 14:56:04 +010044 /* XXX this blocks entire thread. Rewrite to use
45 * qemu_chr_fe_write and background I/O callbacks */
Marc-André Lureau5345fdb2016-10-22 12:52:55 +030046 qemu_chr_fe_write_all(&s->chr, header, sizeof(header));
Anthony Liguori1da27382012-06-25 13:13:31 -050047
48 size -= len;
49 }
Anthony Liguori1da27382012-06-25 13:13:31 -050050}
51
Anthony Liguori1da27382012-06-25 13:13:31 -050052static int rng_egd_chr_can_read(void *opaque)
53{
54 RngEgd *s = RNG_EGD(opaque);
Ladi Prosek443590c2016-03-03 14:16:11 +010055 RngRequest *req;
Anthony Liguori1da27382012-06-25 13:13:31 -050056 int size = 0;
57
Ladi Prosek443590c2016-03-03 14:16:11 +010058 QSIMPLEQ_FOREACH(req, &s->parent.requests, next) {
Anthony Liguori1da27382012-06-25 13:13:31 -050059 size += req->size - req->offset;
60 }
61
62 return size;
63}
64
65static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size)
66{
67 RngEgd *s = RNG_EGD(opaque);
Amos Kong1eb1bd92013-11-21 16:42:51 +080068 size_t buf_offset = 0;
Anthony Liguori1da27382012-06-25 13:13:31 -050069
Ladi Prosek443590c2016-03-03 14:16:11 +010070 while (size > 0 && !QSIMPLEQ_EMPTY(&s->parent.requests)) {
71 RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests);
Anthony Liguori1da27382012-06-25 13:13:31 -050072 int len = MIN(size, req->size - req->offset);
73
Amos Kong1eb1bd92013-11-21 16:42:51 +080074 memcpy(req->data + req->offset, buf + buf_offset, len);
75 buf_offset += len;
Anthony Liguori1da27382012-06-25 13:13:31 -050076 req->offset += len;
77 size -= len;
78
79 if (req->offset == req->size) {
Anthony Liguori1da27382012-06-25 13:13:31 -050080 req->receive_entropy(req->opaque, req->data, req->size);
81
Ladi Prosek9f14b0a2016-03-03 09:37:17 +010082 rng_backend_finalize_request(&s->parent, req);
Anthony Liguori1da27382012-06-25 13:13:31 -050083 }
84 }
85}
86
Anthony Liguori1da27382012-06-25 13:13:31 -050087static void rng_egd_opened(RngBackend *b, Error **errp)
88{
89 RngEgd *s = RNG_EGD(b);
Marc-André Lureau0ec7b3e2016-12-07 16:20:22 +030090 Chardev *chr;
Anthony Liguori1da27382012-06-25 13:13:31 -050091
92 if (s->chr_name == NULL) {
Markus Armbrusterc6bd8c72015-03-17 11:54:50 +010093 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
94 "chardev", "a valid character device");
Anthony Liguori1da27382012-06-25 13:13:31 -050095 return;
96 }
97
Marc-André Lureau32a6ebe2016-10-22 12:52:52 +030098 chr = qemu_chr_find(s->chr_name);
99 if (chr == NULL) {
Markus Armbruster75158eb2015-03-16 08:57:47 +0100100 error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
101 "Device '%s' not found", s->chr_name);
Anthony Liguori1da27382012-06-25 13:13:31 -0500102 return;
103 }
Marc-André Lureau32a6ebe2016-10-22 12:52:52 +0300104 if (!qemu_chr_fe_init(&s->chr, chr, errp)) {
105 return;
106 }
Hans de Goede456d6062013-03-27 20:29:40 +0100107
Anthony Liguori1da27382012-06-25 13:13:31 -0500108 /* FIXME we should resubmit pending requests when the CDS reconnects. */
Marc-André Lureau5345fdb2016-10-22 12:52:55 +0300109 qemu_chr_fe_set_handlers(&s->chr, rng_egd_chr_can_read,
Anton Nefedov81517ba2017-07-06 15:08:49 +0300110 rng_egd_chr_read, NULL, NULL, s, NULL, true);
Anthony Liguori1da27382012-06-25 13:13:31 -0500111}
112
113static void rng_egd_set_chardev(Object *obj, const char *value, Error **errp)
114{
115 RngBackend *b = RNG_BACKEND(obj);
116 RngEgd *s = RNG_EGD(b);
117
118 if (b->opened) {
Markus Armbrusterc6bd8c72015-03-17 11:54:50 +0100119 error_setg(errp, QERR_PERMISSION_DENIED);
Anthony Liguori1da27382012-06-25 13:13:31 -0500120 } else {
Eduardo Habkostabb4d5f2014-09-04 19:10:47 +0300121 g_free(s->chr_name);
Anthony Liguori1da27382012-06-25 13:13:31 -0500122 s->chr_name = g_strdup(value);
123 }
124}
125
126static char *rng_egd_get_chardev(Object *obj, Error **errp)
127{
128 RngEgd *s = RNG_EGD(obj);
Marc-André Lureau0ec7b3e2016-12-07 16:20:22 +0300129 Chardev *chr = qemu_chr_fe_get_driver(&s->chr);
Anthony Liguori1da27382012-06-25 13:13:31 -0500130
Marc-André Lureau5345fdb2016-10-22 12:52:55 +0300131 if (chr && chr->label) {
132 return g_strdup(chr->label);
Anthony Liguori1da27382012-06-25 13:13:31 -0500133 }
134
135 return NULL;
136}
137
138static void rng_egd_init(Object *obj)
139{
140 object_property_add_str(obj, "chardev",
141 rng_egd_get_chardev, rng_egd_set_chardev,
142 NULL);
143}
144
145static void rng_egd_finalize(Object *obj)
146{
147 RngEgd *s = RNG_EGD(obj);
148
Marc-André Lureau1ce26102017-01-27 00:49:13 +0400149 qemu_chr_fe_deinit(&s->chr, false);
Anthony Liguori1da27382012-06-25 13:13:31 -0500150 g_free(s->chr_name);
Anthony Liguori1da27382012-06-25 13:13:31 -0500151}
152
153static void rng_egd_class_init(ObjectClass *klass, void *data)
154{
155 RngBackendClass *rbc = RNG_BACKEND_CLASS(klass);
156
157 rbc->request_entropy = rng_egd_request_entropy;
Anthony Liguori1da27382012-06-25 13:13:31 -0500158 rbc->opened = rng_egd_opened;
159}
160
Andreas Färber8c43a6f2013-01-10 16:19:07 +0100161static const TypeInfo rng_egd_info = {
Anthony Liguori1da27382012-06-25 13:13:31 -0500162 .name = TYPE_RNG_EGD,
163 .parent = TYPE_RNG_BACKEND,
164 .instance_size = sizeof(RngEgd),
165 .class_init = rng_egd_class_init,
166 .instance_init = rng_egd_init,
167 .instance_finalize = rng_egd_finalize,
168};
169
170static void register_types(void)
171{
172 type_register_static(&rng_egd_info);
173}
174
175type_init(register_types);