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1da2738f AL |
1 | /* |
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 | ||
9c058332 | 13 | #include "qemu/osdep.h" |
dccfcd0e PB |
14 | #include "sysemu/rng.h" |
15 | #include "sysemu/char.h" | |
7b1b5d19 | 16 | #include "qapi/qmp/qerror.h" |
1da2738f AL |
17 | #include "hw/qdev.h" /* just for DEFINE_PROP_CHR */ |
18 | ||
19 | #define TYPE_RNG_EGD "rng-egd" | |
20 | #define RNG_EGD(obj) OBJECT_CHECK(RngEgd, (obj), TYPE_RNG_EGD) | |
21 | ||
22 | typedef struct RngEgd | |
23 | { | |
24 | RngBackend parent; | |
25 | ||
26 | CharDriverState *chr; | |
27 | char *chr_name; | |
1da2738f AL |
28 | } RngEgd; |
29 | ||
1da2738f AL |
30 | static void rng_egd_request_entropy(RngBackend *b, size_t size, |
31 | EntropyReceiveFunc *receive_entropy, | |
32 | void *opaque) | |
33 | { | |
34 | RngEgd *s = RNG_EGD(b); | |
35 | RngRequest *req; | |
36 | ||
37 | req = g_malloc(sizeof(*req)); | |
38 | ||
39 | req->offset = 0; | |
40 | req->size = size; | |
41 | req->receive_entropy = receive_entropy; | |
42 | req->opaque = opaque; | |
43 | req->data = g_malloc(req->size); | |
44 | ||
45 | while (size > 0) { | |
46 | uint8_t header[2]; | |
47 | uint8_t len = MIN(size, 255); | |
48 | ||
49 | /* synchronous entropy request */ | |
50 | header[0] = 0x02; | |
51 | header[1] = len; | |
52 | ||
53 | qemu_chr_fe_write(s->chr, header, sizeof(header)); | |
54 | ||
55 | size -= len; | |
56 | } | |
57 | ||
74074e8a | 58 | s->parent.requests = g_slist_append(s->parent.requests, req); |
1da2738f AL |
59 | } |
60 | ||
61 | static void rng_egd_free_request(RngRequest *req) | |
62 | { | |
63 | g_free(req->data); | |
64 | g_free(req); | |
65 | } | |
66 | ||
67 | static int rng_egd_chr_can_read(void *opaque) | |
68 | { | |
69 | RngEgd *s = RNG_EGD(opaque); | |
70 | GSList *i; | |
71 | int size = 0; | |
72 | ||
74074e8a | 73 | for (i = s->parent.requests; i; i = i->next) { |
1da2738f AL |
74 | RngRequest *req = i->data; |
75 | size += req->size - req->offset; | |
76 | } | |
77 | ||
78 | return size; | |
79 | } | |
80 | ||
81 | static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size) | |
82 | { | |
83 | RngEgd *s = RNG_EGD(opaque); | |
1eb1bd9e | 84 | size_t buf_offset = 0; |
1da2738f | 85 | |
74074e8a LP |
86 | while (size > 0 && s->parent.requests) { |
87 | RngRequest *req = s->parent.requests->data; | |
1da2738f AL |
88 | int len = MIN(size, req->size - req->offset); |
89 | ||
1eb1bd9e AK |
90 | memcpy(req->data + req->offset, buf + buf_offset, len); |
91 | buf_offset += len; | |
1da2738f AL |
92 | req->offset += len; |
93 | size -= len; | |
94 | ||
95 | if (req->offset == req->size) { | |
74074e8a LP |
96 | s->parent.requests = g_slist_remove_link(s->parent.requests, |
97 | s->parent.requests); | |
1da2738f AL |
98 | |
99 | req->receive_entropy(req->opaque, req->data, req->size); | |
100 | ||
101 | rng_egd_free_request(req); | |
102 | } | |
103 | } | |
104 | } | |
105 | ||
9cb535fe AL |
106 | static void rng_egd_free_requests(RngEgd *s) |
107 | { | |
108 | GSList *i; | |
109 | ||
74074e8a | 110 | for (i = s->parent.requests; i; i = i->next) { |
9cb535fe AL |
111 | rng_egd_free_request(i->data); |
112 | } | |
113 | ||
74074e8a LP |
114 | g_slist_free(s->parent.requests); |
115 | s->parent.requests = NULL; | |
9cb535fe AL |
116 | } |
117 | ||
1da2738f AL |
118 | static void rng_egd_opened(RngBackend *b, Error **errp) |
119 | { | |
120 | RngEgd *s = RNG_EGD(b); | |
121 | ||
122 | if (s->chr_name == NULL) { | |
c6bd8c70 MA |
123 | error_setg(errp, QERR_INVALID_PARAMETER_VALUE, |
124 | "chardev", "a valid character device"); | |
1da2738f AL |
125 | return; |
126 | } | |
127 | ||
128 | s->chr = qemu_chr_find(s->chr_name); | |
129 | if (s->chr == NULL) { | |
75158ebb MA |
130 | error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND, |
131 | "Device '%s' not found", s->chr_name); | |
1da2738f AL |
132 | return; |
133 | } | |
134 | ||
456d6069 | 135 | if (qemu_chr_fe_claim(s->chr) != 0) { |
c6bd8c70 | 136 | error_setg(errp, QERR_DEVICE_IN_USE, s->chr_name); |
456d6069 HG |
137 | return; |
138 | } | |
139 | ||
1da2738f AL |
140 | /* FIXME we should resubmit pending requests when the CDS reconnects. */ |
141 | qemu_chr_add_handlers(s->chr, rng_egd_chr_can_read, rng_egd_chr_read, | |
142 | NULL, s); | |
143 | } | |
144 | ||
145 | static void rng_egd_set_chardev(Object *obj, const char *value, Error **errp) | |
146 | { | |
147 | RngBackend *b = RNG_BACKEND(obj); | |
148 | RngEgd *s = RNG_EGD(b); | |
149 | ||
150 | if (b->opened) { | |
c6bd8c70 | 151 | error_setg(errp, QERR_PERMISSION_DENIED); |
1da2738f | 152 | } else { |
abb4d5f2 | 153 | g_free(s->chr_name); |
1da2738f AL |
154 | s->chr_name = g_strdup(value); |
155 | } | |
156 | } | |
157 | ||
158 | static char *rng_egd_get_chardev(Object *obj, Error **errp) | |
159 | { | |
160 | RngEgd *s = RNG_EGD(obj); | |
161 | ||
162 | if (s->chr && s->chr->label) { | |
163 | return g_strdup(s->chr->label); | |
164 | } | |
165 | ||
166 | return NULL; | |
167 | } | |
168 | ||
169 | static void rng_egd_init(Object *obj) | |
170 | { | |
171 | object_property_add_str(obj, "chardev", | |
172 | rng_egd_get_chardev, rng_egd_set_chardev, | |
173 | NULL); | |
174 | } | |
175 | ||
176 | static void rng_egd_finalize(Object *obj) | |
177 | { | |
178 | RngEgd *s = RNG_EGD(obj); | |
179 | ||
180 | if (s->chr) { | |
181 | qemu_chr_add_handlers(s->chr, NULL, NULL, NULL, NULL); | |
456d6069 | 182 | qemu_chr_fe_release(s->chr); |
1da2738f AL |
183 | } |
184 | ||
185 | g_free(s->chr_name); | |
186 | ||
9cb535fe | 187 | rng_egd_free_requests(s); |
1da2738f AL |
188 | } |
189 | ||
190 | static void rng_egd_class_init(ObjectClass *klass, void *data) | |
191 | { | |
192 | RngBackendClass *rbc = RNG_BACKEND_CLASS(klass); | |
193 | ||
194 | rbc->request_entropy = rng_egd_request_entropy; | |
1da2738f AL |
195 | rbc->opened = rng_egd_opened; |
196 | } | |
197 | ||
8c43a6f0 | 198 | static const TypeInfo rng_egd_info = { |
1da2738f AL |
199 | .name = TYPE_RNG_EGD, |
200 | .parent = TYPE_RNG_BACKEND, | |
201 | .instance_size = sizeof(RngEgd), | |
202 | .class_init = rng_egd_class_init, | |
203 | .instance_init = rng_egd_init, | |
204 | .instance_finalize = rng_egd_finalize, | |
205 | }; | |
206 | ||
207 | static void register_types(void) | |
208 | { | |
209 | type_register_static(&rng_egd_info); | |
210 | } | |
211 | ||
212 | type_init(register_types); |