From 87e42764490896e66ab8a3c93280384689b0acb4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Mon, 20 Jun 2022 12:01:45 +0100 Subject: [PATCH] io: add a QIOChannelNull equivalent to /dev/null MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This is for code which needs a portable equivalent to a QIOChannelFile connected to /dev/null. Signed-off-by: Daniel P. Berrangé Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela Signed-off-by: Dr. David Alan Gilbert --- include/io/channel-null.h | 55 +++++++ io/channel-null.c | 237 ++++++++++++++++++++++++++++++ io/meson.build | 1 + io/trace-events | 3 + tests/unit/meson.build | 1 + tests/unit/test-io-channel-null.c | 95 ++++++++++++ 6 files changed, 392 insertions(+) create mode 100644 include/io/channel-null.h create mode 100644 io/channel-null.c create mode 100644 tests/unit/test-io-channel-null.c diff --git a/include/io/channel-null.h b/include/io/channel-null.h new file mode 100644 index 0000000000..f6d54e63cf --- /dev/null +++ b/include/io/channel-null.h @@ -0,0 +1,55 @@ +/* + * QEMU I/O channels null driver + * + * Copyright (c) 2022 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see . + * + */ + +#ifndef QIO_CHANNEL_FILE_H +#define QIO_CHANNEL_FILE_H + +#include "io/channel.h" +#include "qom/object.h" + +#define TYPE_QIO_CHANNEL_NULL "qio-channel-null" +OBJECT_DECLARE_SIMPLE_TYPE(QIOChannelNull, QIO_CHANNEL_NULL) + + +/** + * QIOChannelNull: + * + * The QIOChannelNull object provides a channel implementation + * that discards all writes and returns EOF for all reads. + */ + +struct QIOChannelNull { + QIOChannel parent; + bool closed; +}; + + +/** + * qio_channel_null_new: + * + * Create a new IO channel object that discards all writes + * and returns EOF for all reads. + * + * Returns: the new channel object + */ +QIOChannelNull * +qio_channel_null_new(void); + +#endif /* QIO_CHANNEL_NULL_H */ diff --git a/io/channel-null.c b/io/channel-null.c new file mode 100644 index 0000000000..75e3781507 --- /dev/null +++ b/io/channel-null.c @@ -0,0 +1,237 @@ +/* + * QEMU I/O channels null driver + * + * Copyright (c) 2022 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see . + * + */ + +#include "qemu/osdep.h" +#include "io/channel-null.h" +#include "io/channel-watch.h" +#include "qapi/error.h" +#include "trace.h" +#include "qemu/iov.h" + +typedef struct QIOChannelNullSource QIOChannelNullSource; +struct QIOChannelNullSource { + GSource parent; + QIOChannel *ioc; + GIOCondition condition; +}; + + +QIOChannelNull * +qio_channel_null_new(void) +{ + QIOChannelNull *ioc; + + ioc = QIO_CHANNEL_NULL(object_new(TYPE_QIO_CHANNEL_NULL)); + + trace_qio_channel_null_new(ioc); + + return ioc; +} + + +static void +qio_channel_null_init(Object *obj) +{ + QIOChannelNull *ioc = QIO_CHANNEL_NULL(obj); + ioc->closed = false; +} + + +static ssize_t +qio_channel_null_readv(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int **fds G_GNUC_UNUSED, + size_t *nfds G_GNUC_UNUSED, + Error **errp) +{ + QIOChannelNull *nioc = QIO_CHANNEL_NULL(ioc); + + if (nioc->closed) { + error_setg_errno(errp, EINVAL, + "Channel is closed"); + return -1; + } + + return 0; +} + + +static ssize_t +qio_channel_null_writev(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int *fds G_GNUC_UNUSED, + size_t nfds G_GNUC_UNUSED, + int flags G_GNUC_UNUSED, + Error **errp) +{ + QIOChannelNull *nioc = QIO_CHANNEL_NULL(ioc); + + if (nioc->closed) { + error_setg_errno(errp, EINVAL, + "Channel is closed"); + return -1; + } + + return iov_size(iov, niov); +} + + +static int +qio_channel_null_set_blocking(QIOChannel *ioc G_GNUC_UNUSED, + bool enabled G_GNUC_UNUSED, + Error **errp G_GNUC_UNUSED) +{ + return 0; +} + + +static off_t +qio_channel_null_seek(QIOChannel *ioc G_GNUC_UNUSED, + off_t offset G_GNUC_UNUSED, + int whence G_GNUC_UNUSED, + Error **errp G_GNUC_UNUSED) +{ + return 0; +} + + +static int +qio_channel_null_close(QIOChannel *ioc, + Error **errp G_GNUC_UNUSED) +{ + QIOChannelNull *nioc = QIO_CHANNEL_NULL(ioc); + + nioc->closed = true; + return 0; +} + + +static void +qio_channel_null_set_aio_fd_handler(QIOChannel *ioc G_GNUC_UNUSED, + AioContext *ctx G_GNUC_UNUSED, + IOHandler *io_read G_GNUC_UNUSED, + IOHandler *io_write G_GNUC_UNUSED, + void *opaque G_GNUC_UNUSED) +{ +} + + +static gboolean +qio_channel_null_source_prepare(GSource *source G_GNUC_UNUSED, + gint *timeout) +{ + *timeout = -1; + + return TRUE; +} + + +static gboolean +qio_channel_null_source_check(GSource *source G_GNUC_UNUSED) +{ + return TRUE; +} + + +static gboolean +qio_channel_null_source_dispatch(GSource *source, + GSourceFunc callback, + gpointer user_data) +{ + QIOChannelFunc func = (QIOChannelFunc)callback; + QIOChannelNullSource *ssource = (QIOChannelNullSource *)source; + + return (*func)(ssource->ioc, + ssource->condition, + user_data); +} + + +static void +qio_channel_null_source_finalize(GSource *source) +{ + QIOChannelNullSource *ssource = (QIOChannelNullSource *)source; + + object_unref(OBJECT(ssource->ioc)); +} + + +GSourceFuncs qio_channel_null_source_funcs = { + qio_channel_null_source_prepare, + qio_channel_null_source_check, + qio_channel_null_source_dispatch, + qio_channel_null_source_finalize +}; + + +static GSource * +qio_channel_null_create_watch(QIOChannel *ioc, + GIOCondition condition) +{ + GSource *source; + QIOChannelNullSource *ssource; + + source = g_source_new(&qio_channel_null_source_funcs, + sizeof(QIOChannelNullSource)); + ssource = (QIOChannelNullSource *)source; + + ssource->ioc = ioc; + object_ref(OBJECT(ioc)); + + ssource->condition = condition; + + return source; +} + + +static void +qio_channel_null_class_init(ObjectClass *klass, + void *class_data G_GNUC_UNUSED) +{ + QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass); + + ioc_klass->io_writev = qio_channel_null_writev; + ioc_klass->io_readv = qio_channel_null_readv; + ioc_klass->io_set_blocking = qio_channel_null_set_blocking; + ioc_klass->io_seek = qio_channel_null_seek; + ioc_klass->io_close = qio_channel_null_close; + ioc_klass->io_create_watch = qio_channel_null_create_watch; + ioc_klass->io_set_aio_fd_handler = qio_channel_null_set_aio_fd_handler; +} + + +static const TypeInfo qio_channel_null_info = { + .parent = TYPE_QIO_CHANNEL, + .name = TYPE_QIO_CHANNEL_NULL, + .instance_size = sizeof(QIOChannelNull), + .instance_init = qio_channel_null_init, + .class_init = qio_channel_null_class_init, +}; + + +static void +qio_channel_null_register_types(void) +{ + type_register_static(&qio_channel_null_info); +} + +type_init(qio_channel_null_register_types); diff --git a/io/meson.build b/io/meson.build index bbcd3c53a4..283b9b2bdb 100644 --- a/io/meson.build +++ b/io/meson.build @@ -3,6 +3,7 @@ io_ss.add(files( 'channel-buffer.c', 'channel-command.c', 'channel-file.c', + 'channel-null.c', 'channel-socket.c', 'channel-tls.c', 'channel-util.c', diff --git a/io/trace-events b/io/trace-events index c5e814eb44..3cc5cf1efd 100644 --- a/io/trace-events +++ b/io/trace-events @@ -10,6 +10,9 @@ qio_task_thread_result(void *task) "Task thread result task=%p" qio_task_thread_source_attach(void *task, void *source) "Task thread source attach task=%p source=%p" qio_task_thread_source_cancel(void *task, void *source) "Task thread source cancel task=%p source=%p" +# channel-null.c +qio_channel_null_new(void *ioc) "Null new ioc=%p" + # channel-socket.c qio_channel_socket_new(void *ioc) "Socket new ioc=%p" qio_channel_socket_new_fd(void *ioc, int fd) "Socket new ioc=%p fd=%d" diff --git a/tests/unit/meson.build b/tests/unit/meson.build index 287b367ec3..b497a41378 100644 --- a/tests/unit/meson.build +++ b/tests/unit/meson.build @@ -88,6 +88,7 @@ if have_block 'test-io-channel-file': ['io-channel-helpers.c', io], 'test-io-channel-command': ['io-channel-helpers.c', io], 'test-io-channel-buffer': ['io-channel-helpers.c', io], + 'test-io-channel-null': [io], 'test-crypto-ivgen': [io], 'test-crypto-afsplit': [io], 'test-crypto-block': [io], diff --git a/tests/unit/test-io-channel-null.c b/tests/unit/test-io-channel-null.c new file mode 100644 index 0000000000..b3aab17ccc --- /dev/null +++ b/tests/unit/test-io-channel-null.c @@ -0,0 +1,95 @@ +/* + * QEMU I/O channel null test + * + * Copyright (c) 2022 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see . + * + */ + +#include "qemu/osdep.h" +#include "io/channel-null.h" +#include "qapi/error.h" + +static gboolean test_io_channel_watch(QIOChannel *ioc, + GIOCondition condition, + gpointer opaque) +{ + GIOCondition *gotcond = opaque; + *gotcond = condition; + return G_SOURCE_REMOVE; +} + +static void test_io_channel_null_io(void) +{ + g_autoptr(QIOChannelNull) null = qio_channel_null_new(); + char buf[1024]; + GIOCondition gotcond = 0; + Error *local_err = NULL; + + g_assert(qio_channel_write(QIO_CHANNEL(null), + "Hello World", 11, + &error_abort) == 11); + + g_assert(qio_channel_read(QIO_CHANNEL(null), + buf, sizeof(buf), + &error_abort) == 0); + + qio_channel_add_watch(QIO_CHANNEL(null), + G_IO_IN, + test_io_channel_watch, + &gotcond, + NULL); + + g_main_context_iteration(NULL, false); + + g_assert(gotcond == G_IO_IN); + + qio_channel_add_watch(QIO_CHANNEL(null), + G_IO_IN | G_IO_OUT, + test_io_channel_watch, + &gotcond, + NULL); + + g_main_context_iteration(NULL, false); + + g_assert(gotcond == (G_IO_IN | G_IO_OUT)); + + qio_channel_close(QIO_CHANNEL(null), &error_abort); + + g_assert(qio_channel_write(QIO_CHANNEL(null), + "Hello World", 11, + &local_err) == -1); + g_assert_nonnull(local_err); + + g_clear_pointer(&local_err, error_free); + + g_assert(qio_channel_read(QIO_CHANNEL(null), + buf, sizeof(buf), + &local_err) == -1); + g_assert_nonnull(local_err); + + g_clear_pointer(&local_err, error_free); +} + +int main(int argc, char **argv) +{ + module_call_init(MODULE_INIT_QOM); + + g_test_init(&argc, &argv, NULL); + + g_test_add_func("/io/channel/null/io", test_io_channel_null_io); + + return g_test_run(); +}