diff options
| -rw-r--r-- | backends/Makefile.objs | 2 | ||||
| -rw-r--r-- | backends/rng-random.c | 161 | ||||
| -rw-r--r-- | include/qemu/rng-random.h | 22 |
3 files changed, 184 insertions, 1 deletions
diff --git a/backends/Makefile.objs b/backends/Makefile.objs index 06e08c782d..23ca19b320 100644 --- a/backends/Makefile.objs +++ b/backends/Makefile.objs @@ -1 +1 @@ -common-obj-y += rng.o +common-obj-y += rng.o rng-random.o diff --git a/backends/rng-random.c b/backends/rng-random.c new file mode 100644 index 0000000000..9c9923b2ac --- /dev/null +++ b/backends/rng-random.c @@ -0,0 +1,161 @@ +/* + * 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/rng-random.h" +#include "qemu/rng.h" +#include "qerror.h" +#include "main-loop.h" + +struct RndRandom +{ + RngBackend parent; + + int fd; + char *filename; + + EntropyReceiveFunc *receive_func; + void *opaque; + size_t size; +}; + +/** + * A simple and incomplete backend to request entropy from /dev/random. + * + * This backend exposes an additional "filename" property that can be used to + * set the filename to use to open the backend. + */ + +static void entropy_available(void *opaque) +{ + RndRandom *s = RNG_RANDOM(opaque); + uint8_t buffer[s->size]; + ssize_t len; + + len = read(s->fd, buffer, s->size); + g_assert(len != -1); + + s->receive_func(s->opaque, buffer, len); + s->receive_func = NULL; + + qemu_set_fd_handler(s->fd, NULL, NULL, NULL); +} + +static void rng_random_request_entropy(RngBackend *b, size_t size, + EntropyReceiveFunc *receive_entropy, + void *opaque) +{ + RndRandom *s = RNG_RANDOM(b); + + if (s->receive_func) { + s->receive_func(s->opaque, NULL, 0); + } + + s->receive_func = receive_entropy; + s->opaque = opaque; + s->size = size; + + qemu_set_fd_handler(s->fd, entropy_available, NULL, s); +} + +static void rng_random_opened(RngBackend *b, Error **errp) +{ + RndRandom *s = RNG_RANDOM(b); + + if (s->filename == NULL) { + error_set(errp, QERR_INVALID_PARAMETER_VALUE, + "filename", "a valid filename"); + } else { + s->fd = open(s->filename, O_RDONLY | O_NONBLOCK); + + if (s->fd == -1) { + error_set(errp, QERR_OPEN_FILE_FAILED, s->filename); + } + } +} + +static char *rng_random_get_filename(Object *obj, Error **errp) +{ + RndRandom *s = RNG_RANDOM(obj); + + if (s->filename) { + return g_strdup(s->filename); + } + + return NULL; +} + +static void rng_random_set_filename(Object *obj, const char *filename, + Error **errp) +{ + RngBackend *b = RNG_BACKEND(obj); + RndRandom *s = RNG_RANDOM(obj); + + if (b->opened) { + error_set(errp, QERR_PERMISSION_DENIED); + return; + } + + if (s->filename) { + g_free(s->filename); + } + + s->filename = g_strdup(filename); +} + +static void rng_random_init(Object *obj) +{ + RndRandom *s = RNG_RANDOM(obj); + + object_property_add_str(obj, "filename", + rng_random_get_filename, + rng_random_set_filename, + NULL); + + s->filename = g_strdup("/dev/random"); +} + +static void rng_random_finalize(Object *obj) +{ + RndRandom *s = RNG_RANDOM(obj); + + qemu_set_fd_handler(s->fd, NULL, NULL, NULL); + + if (s->fd != -1) { + close(s->fd); + } + + g_free(s->filename); +} + +static void rng_random_class_init(ObjectClass *klass, void *data) +{ + RngBackendClass *rbc = RNG_BACKEND_CLASS(klass); + + rbc->request_entropy = rng_random_request_entropy; + rbc->opened = rng_random_opened; +} + +static TypeInfo rng_random_info = { + .name = TYPE_RNG_RANDOM, + .parent = TYPE_RNG_BACKEND, + .instance_size = sizeof(RndRandom), + .class_init = rng_random_class_init, + .instance_init = rng_random_init, + .instance_finalize = rng_random_finalize, +}; + +static void register_types(void) +{ + type_register_static(&rng_random_info); +} + +type_init(register_types); diff --git a/include/qemu/rng-random.h b/include/qemu/rng-random.h new file mode 100644 index 0000000000..6249290cc4 --- /dev/null +++ b/include/qemu/rng-random.h @@ -0,0 +1,22 @@ +/* + * 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. + */ +#ifndef QEMU_RNG_RANDOM_H +#define QEMU_RNG_RANDOM_H + +#include "qemu/object.h" + +#define TYPE_RNG_RANDOM "rng-random" +#define RNG_RANDOM(obj) OBJECT_CHECK(RndRandom, (obj), TYPE_RNG_RANDOM) + +typedef struct RndRandom RndRandom; + +#endif |