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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 | 14 | #include "sysemu/rng.h" |
4d43a603 | 15 | #include "chardev/char-fe.h" |
da34e65c | 16 | #include "qapi/error.h" |
7b1b5d19 | 17 | #include "qapi/qmp/qerror.h" |
0b8fa32f | 18 | #include "qemu/module.h" |
db1015e9 | 19 | #include "qom/object.h" |
1da2738f AL |
20 | |
21 | #define TYPE_RNG_EGD "rng-egd" | |
8063396b | 22 | OBJECT_DECLARE_SIMPLE_TYPE(RngEgd, RNG_EGD) |
1da2738f | 23 | |
db1015e9 | 24 | struct RngEgd { |
1da2738f AL |
25 | RngBackend parent; |
26 | ||
32a6ebec | 27 | CharBackend chr; |
1da2738f | 28 | char *chr_name; |
db1015e9 | 29 | }; |
1da2738f | 30 | |
60253ed1 | 31 | static void rng_egd_request_entropy(RngBackend *b, RngRequest *req) |
1da2738f AL |
32 | { |
33 | RngEgd *s = RNG_EGD(b); | |
60253ed1 | 34 | size_t size = req->size; |
1da2738f AL |
35 | |
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 | ||
6ab3fc32 DB |
44 | /* XXX this blocks entire thread. Rewrite to use |
45 | * qemu_chr_fe_write and background I/O callbacks */ | |
5345fdb4 | 46 | qemu_chr_fe_write_all(&s->chr, header, sizeof(header)); |
1da2738f AL |
47 | |
48 | size -= len; | |
49 | } | |
1da2738f AL |
50 | } |
51 | ||
1da2738f AL |
52 | static int rng_egd_chr_can_read(void *opaque) |
53 | { | |
54 | RngEgd *s = RNG_EGD(opaque); | |
443590c2 | 55 | RngRequest *req; |
1da2738f AL |
56 | int size = 0; |
57 | ||
443590c2 | 58 | QSIMPLEQ_FOREACH(req, &s->parent.requests, next) { |
1da2738f AL |
59 | size += req->size - req->offset; |
60 | } | |
61 | ||
62 | return size; | |
63 | } | |
64 | ||
65 | static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size) | |
66 | { | |
67 | RngEgd *s = RNG_EGD(opaque); | |
1eb1bd9e | 68 | size_t buf_offset = 0; |
1da2738f | 69 | |
443590c2 LP |
70 | while (size > 0 && !QSIMPLEQ_EMPTY(&s->parent.requests)) { |
71 | RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests); | |
1da2738f AL |
72 | int len = MIN(size, req->size - req->offset); |
73 | ||
1eb1bd9e AK |
74 | memcpy(req->data + req->offset, buf + buf_offset, len); |
75 | buf_offset += len; | |
1da2738f AL |
76 | req->offset += len; |
77 | size -= len; | |
78 | ||
79 | if (req->offset == req->size) { | |
1da2738f AL |
80 | req->receive_entropy(req->opaque, req->data, req->size); |
81 | ||
9f14b0ad | 82 | rng_backend_finalize_request(&s->parent, req); |
1da2738f AL |
83 | } |
84 | } | |
85 | } | |
86 | ||
1da2738f AL |
87 | static void rng_egd_opened(RngBackend *b, Error **errp) |
88 | { | |
89 | RngEgd *s = RNG_EGD(b); | |
0ec7b3e7 | 90 | Chardev *chr; |
1da2738f AL |
91 | |
92 | if (s->chr_name == NULL) { | |
c6bd8c70 MA |
93 | error_setg(errp, QERR_INVALID_PARAMETER_VALUE, |
94 | "chardev", "a valid character device"); | |
1da2738f AL |
95 | return; |
96 | } | |
97 | ||
32a6ebec MAL |
98 | chr = qemu_chr_find(s->chr_name); |
99 | if (chr == NULL) { | |
75158ebb MA |
100 | error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND, |
101 | "Device '%s' not found", s->chr_name); | |
1da2738f AL |
102 | return; |
103 | } | |
32a6ebec MAL |
104 | if (!qemu_chr_fe_init(&s->chr, chr, errp)) { |
105 | return; | |
106 | } | |
456d6069 | 107 | |
1da2738f | 108 | /* FIXME we should resubmit pending requests when the CDS reconnects. */ |
5345fdb4 | 109 | qemu_chr_fe_set_handlers(&s->chr, rng_egd_chr_can_read, |
81517ba3 | 110 | rng_egd_chr_read, NULL, NULL, s, NULL, true); |
1da2738f AL |
111 | } |
112 | ||
113 | static 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) { | |
ff924448 | 119 | error_setg(errp, "Property 'chardev' can no longer be set"); |
1da2738f | 120 | } else { |
abb4d5f2 | 121 | g_free(s->chr_name); |
1da2738f AL |
122 | s->chr_name = g_strdup(value); |
123 | } | |
124 | } | |
125 | ||
126 | static char *rng_egd_get_chardev(Object *obj, Error **errp) | |
127 | { | |
128 | RngEgd *s = RNG_EGD(obj); | |
0ec7b3e7 | 129 | Chardev *chr = qemu_chr_fe_get_driver(&s->chr); |
1da2738f | 130 | |
5345fdb4 MAL |
131 | if (chr && chr->label) { |
132 | return g_strdup(chr->label); | |
1da2738f AL |
133 | } |
134 | ||
135 | return NULL; | |
136 | } | |
137 | ||
1da2738f AL |
138 | static void rng_egd_finalize(Object *obj) |
139 | { | |
140 | RngEgd *s = RNG_EGD(obj); | |
141 | ||
1ce2610c | 142 | qemu_chr_fe_deinit(&s->chr, false); |
1da2738f | 143 | g_free(s->chr_name); |
1da2738f AL |
144 | } |
145 | ||
146 | static void rng_egd_class_init(ObjectClass *klass, void *data) | |
147 | { | |
148 | RngBackendClass *rbc = RNG_BACKEND_CLASS(klass); | |
149 | ||
150 | rbc->request_entropy = rng_egd_request_entropy; | |
1da2738f | 151 | rbc->opened = rng_egd_opened; |
079eed2e EH |
152 | object_class_property_add_str(klass, "chardev", |
153 | rng_egd_get_chardev, rng_egd_set_chardev); | |
1da2738f AL |
154 | } |
155 | ||
8c43a6f0 | 156 | static const TypeInfo rng_egd_info = { |
1da2738f AL |
157 | .name = TYPE_RNG_EGD, |
158 | .parent = TYPE_RNG_BACKEND, | |
159 | .instance_size = sizeof(RngEgd), | |
160 | .class_init = rng_egd_class_init, | |
1da2738f AL |
161 | .instance_finalize = rng_egd_finalize, |
162 | }; | |
163 | ||
164 | static void register_types(void) | |
165 | { | |
166 | type_register_static(&rng_egd_info); | |
167 | } | |
168 | ||
169 | type_init(register_types); |