1 files changed, 169 insertions, 0 deletions
diff --git a/backends/rng-egd.c b/backends/rng-egd.c
new file mode 100644
index 000000000..4de142b9d
--- /dev/null
+++ b/backends/rng-egd.c
@@ -0,0 +1,169 @@
+/*
+ * QEMU Random Number Generator Backend
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "sysemu/rng.h"
+#include "chardev/char-fe.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qerror.h"
+#include "qemu/module.h"
+#include "qom/object.h"
+
+#define TYPE_RNG_EGD "rng-egd"
+OBJECT_DECLARE_SIMPLE_TYPE(RngEgd, RNG_EGD)
+
+struct RngEgd {
+    RngBackend parent;
+
+    CharBackend chr;
+    char *chr_name;
+};
+
+static void rng_egd_request_entropy(RngBackend *b, RngRequest *req)
+{
+    RngEgd *s = RNG_EGD(b);
+    size_t size = req->size;
+
+    while (size > 0) {
+        uint8_t header[2];
+        uint8_t len = MIN(size, 255);
+
+        /* synchronous entropy request */
+        header[0] = 0x02;
+        header[1] = len;
+
+        /* XXX this blocks entire thread. Rewrite to use
+         * qemu_chr_fe_write and background I/O callbacks */
+        qemu_chr_fe_write_all(&s->chr, header, sizeof(header));
+
+        size -= len;
+    }
+}
+
+static int rng_egd_chr_can_read(void *opaque)
+{
+    RngEgd *s = RNG_EGD(opaque);
+    RngRequest *req;
+    int size = 0;
+
+    QSIMPLEQ_FOREACH(req, &s->parent.requests, next) {
+        size += req->size - req->offset;
+    }
+
+    return size;
+}
+
+static void rng_egd_chr_read(void *opaque, const uint8_t *buf, int size)
+{
+    RngEgd *s = RNG_EGD(opaque);
+    size_t buf_offset = 0;
+
+    while (size > 0 && !QSIMPLEQ_EMPTY(&s->parent.requests)) {
+        RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests);
+        int len = MIN(size, req->size - req->offset);
+
+        memcpy(req->data + req->offset, buf + buf_offset, len);
+        buf_offset += len;
+        req->offset += len;
+        size -= len;
+
+        if (req->offset == req->size) {
+            req->receive_entropy(req->opaque, req->data, req->size);
+
+            rng_backend_finalize_request(&s->parent, req);
+        }
+    }
+}
+
+static void rng_egd_opened(RngBackend *b, Error **errp)
+{
+    RngEgd *s = RNG_EGD(b);
+    Chardev *chr;
+
+    if (s->chr_name == NULL) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
+                   "chardev", "a valid character device");
+        return;
+    }
+
+    chr = qemu_chr_find(s->chr_name);
+    if (chr == NULL) {
+        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                  "Device '%s' not found", s->chr_name);
+        return;
+    }
+    if (!qemu_chr_fe_init(&s->chr, chr, errp)) {
+        return;
+    }
+
+    /* FIXME we should resubmit pending requests when the CDS reconnects. */
+    qemu_chr_fe_set_handlers(&s->chr, rng_egd_chr_can_read,
+                             rng_egd_chr_read, NULL, NULL, s, NULL, true);
+}
+
+static void rng_egd_set_chardev(Object *obj, const char *value, Error **errp)
+{
+    RngBackend *b = RNG_BACKEND(obj);
+    RngEgd *s = RNG_EGD(b);
+
+    if (b->opened) {
+        error_setg(errp, QERR_PERMISSION_DENIED);
+    } else {
+        g_free(s->chr_name);
+        s->chr_name = g_strdup(value);
+    }
+}
+
+static char *rng_egd_get_chardev(Object *obj, Error **errp)
+{
+    RngEgd *s = RNG_EGD(obj);
+    Chardev *chr = qemu_chr_fe_get_driver(&s->chr);
+
+    if (chr && chr->label) {
+        return g_strdup(chr->label);
+    }
+
+    return NULL;
+}
+
+static void rng_egd_finalize(Object *obj)
+{
+    RngEgd *s = RNG_EGD(obj);
+
+    qemu_chr_fe_deinit(&s->chr, false);
+    g_free(s->chr_name);
+}
+
+static void rng_egd_class_init(ObjectClass *klass, void *data)
+{
+    RngBackendClass *rbc = RNG_BACKEND_CLASS(klass);
+
+    rbc->request_entropy = rng_egd_request_entropy;
+    rbc->opened = rng_egd_opened;
+    object_class_property_add_str(klass, "chardev",
+                                  rng_egd_get_chardev, rng_egd_set_chardev);
+}
+
+static const TypeInfo rng_egd_info = {
+    .name = TYPE_RNG_EGD,
+    .parent = TYPE_RNG_BACKEND,
+    .instance_size = sizeof(RngEgd),
+    .class_init = rng_egd_class_init,
+    .instance_finalize = rng_egd_finalize,
+};
+
+static void register_types(void)
+{
+    type_register_static(&rng_egd_info);
+}
+
+type_init(register_types);