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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" | |
da34e65c | 16 | #include "qapi/error.h" |
7b1b5d19 | 17 | #include "qapi/qmp/qerror.h" |
1da2738f AL |
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 | ||
32a6ebec | 26 | CharBackend chr; |
1da2738f | 27 | char *chr_name; |
1da2738f AL |
28 | } RngEgd; |
29 | ||
60253ed1 | 30 | static void rng_egd_request_entropy(RngBackend *b, RngRequest *req) |
1da2738f AL |
31 | { |
32 | RngEgd *s = RNG_EGD(b); | |
60253ed1 | 33 | size_t size = req->size; |
1da2738f AL |
34 | |
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 | ||
6ab3fc32 DB |
43 | /* XXX this blocks entire thread. Rewrite to use |
44 | * qemu_chr_fe_write and background I/O callbacks */ | |
32a6ebec | 45 | qemu_chr_fe_write_all(s->chr.chr, header, sizeof(header)); |
1da2738f AL |
46 | |
47 | size -= len; | |
48 | } | |
1da2738f AL |
49 | } |
50 | ||
1da2738f AL |
51 | static int rng_egd_chr_can_read(void *opaque) |
52 | { | |
53 | RngEgd *s = RNG_EGD(opaque); | |
443590c2 | 54 | RngRequest *req; |
1da2738f AL |
55 | int size = 0; |
56 | ||
443590c2 | 57 | QSIMPLEQ_FOREACH(req, &s->parent.requests, next) { |
1da2738f AL |
58 | size += req->size - req->offset; |
59 | } | |
60 | ||
61 | return size; | |
62 | } | |
63 | ||
64 | static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size) | |
65 | { | |
66 | RngEgd *s = RNG_EGD(opaque); | |
1eb1bd9e | 67 | size_t buf_offset = 0; |
1da2738f | 68 | |
443590c2 LP |
69 | while (size > 0 && !QSIMPLEQ_EMPTY(&s->parent.requests)) { |
70 | RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests); | |
1da2738f AL |
71 | int len = MIN(size, req->size - req->offset); |
72 | ||
1eb1bd9e AK |
73 | memcpy(req->data + req->offset, buf + buf_offset, len); |
74 | buf_offset += len; | |
1da2738f AL |
75 | req->offset += len; |
76 | size -= len; | |
77 | ||
78 | if (req->offset == req->size) { | |
1da2738f AL |
79 | req->receive_entropy(req->opaque, req->data, req->size); |
80 | ||
9f14b0ad | 81 | rng_backend_finalize_request(&s->parent, req); |
1da2738f AL |
82 | } |
83 | } | |
84 | } | |
85 | ||
1da2738f AL |
86 | static void rng_egd_opened(RngBackend *b, Error **errp) |
87 | { | |
88 | RngEgd *s = RNG_EGD(b); | |
32a6ebec | 89 | CharDriverState *chr; |
1da2738f AL |
90 | |
91 | if (s->chr_name == NULL) { | |
c6bd8c70 MA |
92 | error_setg(errp, QERR_INVALID_PARAMETER_VALUE, |
93 | "chardev", "a valid character device"); | |
1da2738f AL |
94 | return; |
95 | } | |
96 | ||
32a6ebec MAL |
97 | chr = qemu_chr_find(s->chr_name); |
98 | if (chr == NULL) { | |
75158ebb MA |
99 | error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND, |
100 | "Device '%s' not found", s->chr_name); | |
1da2738f AL |
101 | return; |
102 | } | |
32a6ebec | 103 | if (qemu_chr_fe_claim(chr) != 0) { |
c6bd8c70 | 104 | error_setg(errp, QERR_DEVICE_IN_USE, s->chr_name); |
456d6069 HG |
105 | return; |
106 | } | |
32a6ebec MAL |
107 | if (!qemu_chr_fe_init(&s->chr, chr, errp)) { |
108 | return; | |
109 | } | |
456d6069 | 110 | |
1da2738f | 111 | /* FIXME we should resubmit pending requests when the CDS reconnects. */ |
32a6ebec MAL |
112 | qemu_chr_add_handlers(s->chr.chr, rng_egd_chr_can_read, |
113 | rng_egd_chr_read, NULL, s); | |
1da2738f AL |
114 | } |
115 | ||
116 | static void rng_egd_set_chardev(Object *obj, const char *value, Error **errp) | |
117 | { | |
118 | RngBackend *b = RNG_BACKEND(obj); | |
119 | RngEgd *s = RNG_EGD(b); | |
120 | ||
121 | if (b->opened) { | |
c6bd8c70 | 122 | error_setg(errp, QERR_PERMISSION_DENIED); |
1da2738f | 123 | } else { |
abb4d5f2 | 124 | g_free(s->chr_name); |
1da2738f AL |
125 | s->chr_name = g_strdup(value); |
126 | } | |
127 | } | |
128 | ||
129 | static char *rng_egd_get_chardev(Object *obj, Error **errp) | |
130 | { | |
131 | RngEgd *s = RNG_EGD(obj); | |
132 | ||
32a6ebec MAL |
133 | if (s->chr.chr && s->chr.chr->label) { |
134 | return g_strdup(s->chr.chr->label); | |
1da2738f AL |
135 | } |
136 | ||
137 | return NULL; | |
138 | } | |
139 | ||
140 | static void rng_egd_init(Object *obj) | |
141 | { | |
142 | object_property_add_str(obj, "chardev", | |
143 | rng_egd_get_chardev, rng_egd_set_chardev, | |
144 | NULL); | |
145 | } | |
146 | ||
147 | static void rng_egd_finalize(Object *obj) | |
148 | { | |
149 | RngEgd *s = RNG_EGD(obj); | |
150 | ||
32a6ebec MAL |
151 | if (s->chr.chr) { |
152 | qemu_chr_add_handlers(s->chr.chr, NULL, NULL, NULL, NULL); | |
153 | qemu_chr_fe_release(s->chr.chr); | |
1da2738f AL |
154 | } |
155 | ||
156 | g_free(s->chr_name); | |
1da2738f AL |
157 | } |
158 | ||
159 | static void rng_egd_class_init(ObjectClass *klass, void *data) | |
160 | { | |
161 | RngBackendClass *rbc = RNG_BACKEND_CLASS(klass); | |
162 | ||
163 | rbc->request_entropy = rng_egd_request_entropy; | |
1da2738f AL |
164 | rbc->opened = rng_egd_opened; |
165 | } | |
166 | ||
8c43a6f0 | 167 | static const TypeInfo rng_egd_info = { |
1da2738f AL |
168 | .name = TYPE_RNG_EGD, |
169 | .parent = TYPE_RNG_BACKEND, | |
170 | .instance_size = sizeof(RngEgd), | |
171 | .class_init = rng_egd_class_init, | |
172 | .instance_init = rng_egd_init, | |
173 | .instance_finalize = rng_egd_finalize, | |
174 | }; | |
175 | ||
176 | static void register_types(void) | |
177 | { | |
178 | type_register_static(&rng_egd_info); | |
179 | } | |
180 | ||
181 | type_init(register_types); |