diff options
Diffstat (limited to 'io/channel.c')
| -rw-r--r-- | io/channel.c | 623 |
1 files changed, 623 insertions, 0 deletions
diff --git a/io/channel.c b/io/channel.c new file mode 100644 index 000000000..e8b019dc3 --- /dev/null +++ b/io/channel.c @@ -0,0 +1,623 @@ +/* + * QEMU I/O channels + * + * Copyright (c) 2015 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 <http://www.gnu.org/licenses/>. + * + */ + +#include "qemu/osdep.h" +#include "io/channel.h" +#include "qapi/error.h" +#include "qemu/main-loop.h" +#include "qemu/module.h" +#include "qemu/iov.h" + +bool qio_channel_has_feature(QIOChannel *ioc, + QIOChannelFeature feature) +{ + return ioc->features & (1 << feature); +} + + +void qio_channel_set_feature(QIOChannel *ioc, + QIOChannelFeature feature) +{ + ioc->features |= (1 << feature); +} + + +void qio_channel_set_name(QIOChannel *ioc, + const char *name) +{ + g_free(ioc->name); + ioc->name = g_strdup(name); +} + + +ssize_t qio_channel_readv_full(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int **fds, + size_t *nfds, + Error **errp) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + + if ((fds || nfds) && + !qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) { + error_setg_errno(errp, EINVAL, + "Channel does not support file descriptor passing"); + return -1; + } + + return klass->io_readv(ioc, iov, niov, fds, nfds, errp); +} + + +ssize_t qio_channel_writev_full(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int *fds, + size_t nfds, + Error **errp) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + + if ((fds || nfds) && + !qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) { + error_setg_errno(errp, EINVAL, + "Channel does not support file descriptor passing"); + return -1; + } + + return klass->io_writev(ioc, iov, niov, fds, nfds, errp); +} + + +int qio_channel_readv_all_eof(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + Error **errp) +{ + return qio_channel_readv_full_all_eof(ioc, iov, niov, NULL, NULL, errp); +} + +int qio_channel_readv_all(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + Error **errp) +{ + return qio_channel_readv_full_all(ioc, iov, niov, NULL, NULL, errp); +} + +int qio_channel_readv_full_all_eof(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int **fds, size_t *nfds, + Error **errp) +{ + int ret = -1; + struct iovec *local_iov = g_new(struct iovec, niov); + struct iovec *local_iov_head = local_iov; + unsigned int nlocal_iov = niov; + int **local_fds = fds; + size_t *local_nfds = nfds; + bool partial = false; + + if (nfds) { + *nfds = 0; + } + + if (fds) { + *fds = NULL; + } + + nlocal_iov = iov_copy(local_iov, nlocal_iov, + iov, niov, + 0, iov_size(iov, niov)); + + while ((nlocal_iov > 0) || local_fds) { + ssize_t len; + len = qio_channel_readv_full(ioc, local_iov, nlocal_iov, local_fds, + local_nfds, errp); + if (len == QIO_CHANNEL_ERR_BLOCK) { + if (qemu_in_coroutine()) { + qio_channel_yield(ioc, G_IO_IN); + } else { + qio_channel_wait(ioc, G_IO_IN); + } + continue; + } + + if (len == 0) { + if (local_nfds && *local_nfds) { + /* + * Got some FDs, but no data yet. This isn't an EOF + * scenario (yet), so carry on to try to read data + * on next loop iteration + */ + goto next_iter; + } else if (!partial) { + /* No fds and no data - EOF before any data read */ + ret = 0; + goto cleanup; + } else { + len = -1; + error_setg(errp, + "Unexpected end-of-file before all data were read"); + /* Fallthrough into len < 0 handling */ + } + } + + if (len < 0) { + /* Close any FDs we previously received */ + if (nfds && fds) { + size_t i; + for (i = 0; i < (*nfds); i++) { + close((*fds)[i]); + } + g_free(*fds); + *fds = NULL; + *nfds = 0; + } + goto cleanup; + } + + if (nlocal_iov) { + iov_discard_front(&local_iov, &nlocal_iov, len); + } + +next_iter: + partial = true; + local_fds = NULL; + local_nfds = NULL; + } + + ret = 1; + + cleanup: + g_free(local_iov_head); + return ret; +} + +int qio_channel_readv_full_all(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int **fds, size_t *nfds, + Error **errp) +{ + int ret = qio_channel_readv_full_all_eof(ioc, iov, niov, fds, nfds, errp); + + if (ret == 0) { + error_setg(errp, "Unexpected end-of-file before all data were read"); + return -1; + } + if (ret == 1) { + return 0; + } + + return ret; +} + +int qio_channel_writev_all(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + Error **errp) +{ + return qio_channel_writev_full_all(ioc, iov, niov, NULL, 0, errp); +} + +int qio_channel_writev_full_all(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int *fds, size_t nfds, + Error **errp) +{ + int ret = -1; + struct iovec *local_iov = g_new(struct iovec, niov); + struct iovec *local_iov_head = local_iov; + unsigned int nlocal_iov = niov; + + nlocal_iov = iov_copy(local_iov, nlocal_iov, + iov, niov, + 0, iov_size(iov, niov)); + + while (nlocal_iov > 0) { + ssize_t len; + len = qio_channel_writev_full(ioc, local_iov, nlocal_iov, fds, nfds, + errp); + if (len == QIO_CHANNEL_ERR_BLOCK) { + if (qemu_in_coroutine()) { + qio_channel_yield(ioc, G_IO_OUT); + } else { + qio_channel_wait(ioc, G_IO_OUT); + } + continue; + } + if (len < 0) { + goto cleanup; + } + + iov_discard_front(&local_iov, &nlocal_iov, len); + + fds = NULL; + nfds = 0; + } + + ret = 0; + cleanup: + g_free(local_iov_head); + return ret; +} + +ssize_t qio_channel_readv(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + Error **errp) +{ + return qio_channel_readv_full(ioc, iov, niov, NULL, NULL, errp); +} + + +ssize_t qio_channel_writev(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + Error **errp) +{ + return qio_channel_writev_full(ioc, iov, niov, NULL, 0, errp); +} + + +ssize_t qio_channel_read(QIOChannel *ioc, + char *buf, + size_t buflen, + Error **errp) +{ + struct iovec iov = { .iov_base = buf, .iov_len = buflen }; + return qio_channel_readv_full(ioc, &iov, 1, NULL, NULL, errp); +} + + +ssize_t qio_channel_write(QIOChannel *ioc, + const char *buf, + size_t buflen, + Error **errp) +{ + struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen }; + return qio_channel_writev_full(ioc, &iov, 1, NULL, 0, errp); +} + + +int qio_channel_read_all_eof(QIOChannel *ioc, + char *buf, + size_t buflen, + Error **errp) +{ + struct iovec iov = { .iov_base = buf, .iov_len = buflen }; + return qio_channel_readv_all_eof(ioc, &iov, 1, errp); +} + + +int qio_channel_read_all(QIOChannel *ioc, + char *buf, + size_t buflen, + Error **errp) +{ + struct iovec iov = { .iov_base = buf, .iov_len = buflen }; + return qio_channel_readv_all(ioc, &iov, 1, errp); +} + + +int qio_channel_write_all(QIOChannel *ioc, + const char *buf, + size_t buflen, + Error **errp) +{ + struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen }; + return qio_channel_writev_all(ioc, &iov, 1, errp); +} + + +int qio_channel_set_blocking(QIOChannel *ioc, + bool enabled, + Error **errp) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + return klass->io_set_blocking(ioc, enabled, errp); +} + + +int qio_channel_close(QIOChannel *ioc, + Error **errp) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + return klass->io_close(ioc, errp); +} + + +GSource *qio_channel_create_watch(QIOChannel *ioc, + GIOCondition condition) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + GSource *ret = klass->io_create_watch(ioc, condition); + + if (ioc->name) { + g_source_set_name(ret, ioc->name); + } + + return ret; +} + + +void qio_channel_set_aio_fd_handler(QIOChannel *ioc, + AioContext *ctx, + IOHandler *io_read, + IOHandler *io_write, + void *opaque) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + + klass->io_set_aio_fd_handler(ioc, ctx, io_read, io_write, opaque); +} + +guint qio_channel_add_watch_full(QIOChannel *ioc, + GIOCondition condition, + QIOChannelFunc func, + gpointer user_data, + GDestroyNotify notify, + GMainContext *context) +{ + GSource *source; + guint id; + + source = qio_channel_create_watch(ioc, condition); + + g_source_set_callback(source, (GSourceFunc)func, user_data, notify); + + id = g_source_attach(source, context); + g_source_unref(source); + + return id; +} + +guint qio_channel_add_watch(QIOChannel *ioc, + GIOCondition condition, + QIOChannelFunc func, + gpointer user_data, + GDestroyNotify notify) +{ + return qio_channel_add_watch_full(ioc, condition, func, + user_data, notify, NULL); +} + +GSource *qio_channel_add_watch_source(QIOChannel *ioc, + GIOCondition condition, + QIOChannelFunc func, + gpointer user_data, + GDestroyNotify notify, + GMainContext *context) +{ + GSource *source; + guint id; + + id = qio_channel_add_watch_full(ioc, condition, func, + user_data, notify, context); + source = g_main_context_find_source_by_id(context, id); + g_source_ref(source); + return source; +} + + +int qio_channel_shutdown(QIOChannel *ioc, + QIOChannelShutdown how, + Error **errp) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + + if (!klass->io_shutdown) { + error_setg(errp, "Data path shutdown not supported"); + return -1; + } + + return klass->io_shutdown(ioc, how, errp); +} + + +void qio_channel_set_delay(QIOChannel *ioc, + bool enabled) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + + if (klass->io_set_delay) { + klass->io_set_delay(ioc, enabled); + } +} + + +void qio_channel_set_cork(QIOChannel *ioc, + bool enabled) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + + if (klass->io_set_cork) { + klass->io_set_cork(ioc, enabled); + } +} + + +off_t qio_channel_io_seek(QIOChannel *ioc, + off_t offset, + int whence, + Error **errp) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + + if (!klass->io_seek) { + error_setg(errp, "Channel does not support random access"); + return -1; + } + + return klass->io_seek(ioc, offset, whence, errp); +} + + +static void qio_channel_restart_read(void *opaque) +{ + QIOChannel *ioc = opaque; + Coroutine *co = ioc->read_coroutine; + + /* Assert that aio_co_wake() reenters the coroutine directly */ + assert(qemu_get_current_aio_context() == + qemu_coroutine_get_aio_context(co)); + aio_co_wake(co); +} + +static void qio_channel_restart_write(void *opaque) +{ + QIOChannel *ioc = opaque; + Coroutine *co = ioc->write_coroutine; + + /* Assert that aio_co_wake() reenters the coroutine directly */ + assert(qemu_get_current_aio_context() == + qemu_coroutine_get_aio_context(co)); + aio_co_wake(co); +} + +static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc) +{ + IOHandler *rd_handler = NULL, *wr_handler = NULL; + AioContext *ctx; + + if (ioc->read_coroutine) { + rd_handler = qio_channel_restart_read; + } + if (ioc->write_coroutine) { + wr_handler = qio_channel_restart_write; + } + + ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context(); + qio_channel_set_aio_fd_handler(ioc, ctx, rd_handler, wr_handler, ioc); +} + +void qio_channel_attach_aio_context(QIOChannel *ioc, + AioContext *ctx) +{ + assert(!ioc->read_coroutine); + assert(!ioc->write_coroutine); + ioc->ctx = ctx; +} + +void qio_channel_detach_aio_context(QIOChannel *ioc) +{ + ioc->read_coroutine = NULL; + ioc->write_coroutine = NULL; + qio_channel_set_aio_fd_handlers(ioc); + ioc->ctx = NULL; +} + +void coroutine_fn qio_channel_yield(QIOChannel *ioc, + GIOCondition condition) +{ + assert(qemu_in_coroutine()); + if (condition == G_IO_IN) { + assert(!ioc->read_coroutine); + ioc->read_coroutine = qemu_coroutine_self(); + } else if (condition == G_IO_OUT) { + assert(!ioc->write_coroutine); + ioc->write_coroutine = qemu_coroutine_self(); + } else { + abort(); + } + qio_channel_set_aio_fd_handlers(ioc); + qemu_coroutine_yield(); + + /* Allow interrupting the operation by reentering the coroutine other than + * through the aio_fd_handlers. */ + if (condition == G_IO_IN && ioc->read_coroutine) { + ioc->read_coroutine = NULL; + qio_channel_set_aio_fd_handlers(ioc); + } else if (condition == G_IO_OUT && ioc->write_coroutine) { + ioc->write_coroutine = NULL; + qio_channel_set_aio_fd_handlers(ioc); + } +} + + +static gboolean qio_channel_wait_complete(QIOChannel *ioc, + GIOCondition condition, + gpointer opaque) +{ + GMainLoop *loop = opaque; + + g_main_loop_quit(loop); + return FALSE; +} + + +void qio_channel_wait(QIOChannel *ioc, + GIOCondition condition) +{ + GMainContext *ctxt = g_main_context_new(); + GMainLoop *loop = g_main_loop_new(ctxt, TRUE); + GSource *source; + + source = qio_channel_create_watch(ioc, condition); + + g_source_set_callback(source, + (GSourceFunc)qio_channel_wait_complete, + loop, + NULL); + + g_source_attach(source, ctxt); + + g_main_loop_run(loop); + + g_source_unref(source); + g_main_loop_unref(loop); + g_main_context_unref(ctxt); +} + + +static void qio_channel_finalize(Object *obj) +{ + QIOChannel *ioc = QIO_CHANNEL(obj); + + g_free(ioc->name); + +#ifdef _WIN32 + if (ioc->event) { + CloseHandle(ioc->event); + } +#endif +} + +static const TypeInfo qio_channel_info = { + .parent = TYPE_OBJECT, + .name = TYPE_QIO_CHANNEL, + .instance_size = sizeof(QIOChannel), + .instance_finalize = qio_channel_finalize, + .abstract = true, + .class_size = sizeof(QIOChannelClass), +}; + + +static void qio_channel_register_types(void) +{ + type_register_static(&qio_channel_info); +} + + +type_init(qio_channel_register_types); |