migration: split migration hooks out of QEMUFileOps
[qemu.git] / backends / rng-egd.c
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
13 #include "qemu/osdep.h"
14 #include "sysemu/rng.h"
15 #include "sysemu/char.h"
16 #include "qapi/error.h"
17 #include "qapi/qmp/qerror.h"
18 #include "hw/qdev.h" /* just for DEFINE_PROP_CHR */
19
20 #define TYPE_RNG_EGD "rng-egd"
21 #define RNG_EGD(obj) OBJECT_CHECK(RngEgd, (obj), TYPE_RNG_EGD)
22
23 typedef struct RngEgd
24 {
25 RngBackend parent;
26
27 CharDriverState *chr;
28 char *chr_name;
29 } RngEgd;
30
31 static void rng_egd_request_entropy(RngBackend *b, RngRequest *req)
32 {
33 RngEgd *s = RNG_EGD(b);
34 size_t size = req->size;
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
44 qemu_chr_fe_write(s->chr, header, sizeof(header));
45
46 size -= len;
47 }
48 }
49
50 static int rng_egd_chr_can_read(void *opaque)
51 {
52 RngEgd *s = RNG_EGD(opaque);
53 RngRequest *req;
54 int size = 0;
55
56 QSIMPLEQ_FOREACH(req, &s->parent.requests, next) {
57 size += req->size - req->offset;
58 }
59
60 return size;
61 }
62
63 static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size)
64 {
65 RngEgd *s = RNG_EGD(opaque);
66 size_t buf_offset = 0;
67
68 while (size > 0 && !QSIMPLEQ_EMPTY(&s->parent.requests)) {
69 RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests);
70 int len = MIN(size, req->size - req->offset);
71
72 memcpy(req->data + req->offset, buf + buf_offset, len);
73 buf_offset += len;
74 req->offset += len;
75 size -= len;
76
77 if (req->offset == req->size) {
78 req->receive_entropy(req->opaque, req->data, req->size);
79
80 rng_backend_finalize_request(&s->parent, req);
81 }
82 }
83 }
84
85 static void rng_egd_opened(RngBackend *b, Error **errp)
86 {
87 RngEgd *s = RNG_EGD(b);
88
89 if (s->chr_name == NULL) {
90 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
91 "chardev", "a valid character device");
92 return;
93 }
94
95 s->chr = qemu_chr_find(s->chr_name);
96 if (s->chr == NULL) {
97 error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
98 "Device '%s' not found", s->chr_name);
99 return;
100 }
101
102 if (qemu_chr_fe_claim(s->chr) != 0) {
103 error_setg(errp, QERR_DEVICE_IN_USE, s->chr_name);
104 return;
105 }
106
107 /* FIXME we should resubmit pending requests when the CDS reconnects. */
108 qemu_chr_add_handlers(s->chr, rng_egd_chr_can_read, rng_egd_chr_read,
109 NULL, s);
110 }
111
112 static 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) {
118 error_setg(errp, QERR_PERMISSION_DENIED);
119 } else {
120 g_free(s->chr_name);
121 s->chr_name = g_strdup(value);
122 }
123 }
124
125 static char *rng_egd_get_chardev(Object *obj, Error **errp)
126 {
127 RngEgd *s = RNG_EGD(obj);
128
129 if (s->chr && s->chr->label) {
130 return g_strdup(s->chr->label);
131 }
132
133 return NULL;
134 }
135
136 static void rng_egd_init(Object *obj)
137 {
138 object_property_add_str(obj, "chardev",
139 rng_egd_get_chardev, rng_egd_set_chardev,
140 NULL);
141 }
142
143 static void rng_egd_finalize(Object *obj)
144 {
145 RngEgd *s = RNG_EGD(obj);
146
147 if (s->chr) {
148 qemu_chr_add_handlers(s->chr, NULL, NULL, NULL, NULL);
149 qemu_chr_fe_release(s->chr);
150 }
151
152 g_free(s->chr_name);
153 }
154
155 static void rng_egd_class_init(ObjectClass *klass, void *data)
156 {
157 RngBackendClass *rbc = RNG_BACKEND_CLASS(klass);
158
159 rbc->request_entropy = rng_egd_request_entropy;
160 rbc->opened = rng_egd_opened;
161 }
162
163 static const TypeInfo rng_egd_info = {
164 .name = TYPE_RNG_EGD,
165 .parent = TYPE_RNG_BACKEND,
166 .instance_size = sizeof(RngEgd),
167 .class_init = rng_egd_class_init,
168 .instance_init = rng_egd_init,
169 .instance_finalize = rng_egd_finalize,
170 };
171
172 static void register_types(void)
173 {
174 type_register_static(&rng_egd_info);
175 }
176
177 type_init(register_types);