From: "Daniel P. Berrange" Date: Wed, 30 Aug 2017 14:53:59 +0100 Subject: [PATCH] io: add new qio_channel_{readv, writev, read, write}_all functions These functions wait until they are able to read / write the full requested data buffer(s). Reviewed-by: Eric Blake Signed-off-by: Daniel P. Berrange --- include/io/channel.h | 90 +++++++++++++++++++++++++++++++++++++++ io/channel.c | 94 +++++++++++++++++++++++++++++++++++++++++ tests/io-channel-helpers.c | 102 ++++----------------------------------------- 3 files changed, 193 insertions(+), 93 deletions(-) diff --git a/include/io/channel.h b/include/io/channel.h index db9bb022a1..e11a62ea50 100644 --- a/include/io/channel.h +++ b/include/io/channel.h @@ -268,6 +268,58 @@ ssize_t qio_channel_writev_full(QIOChannel *ioc, size_t nfds, Error **errp); +/** + * qio_channel_readv_all: + * @ioc: the channel object + * @iov: the array of memory regions to read data into + * @niov: the length of the @iov array + * @errp: pointer to a NULL-initialized error object + * + * Read data from the IO channel, storing it in the + * memory regions referenced by @iov. Each element + * in the @iov will be fully populated with data + * before the next one is used. The @niov parameter + * specifies the total number of elements in @iov. + * + * The function will wait for all requested data + * to be read, yielding from the current coroutine + * if required. + * + * If end-of-file occurs before all requested data + * has been read, an error will be reported. + * + * Returns: 0 if all bytes were read, or -1 on error + */ +int qio_channel_readv_all(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + Error **errp); + + +/** + * qio_channel_writev_all: + * @ioc: the channel object + * @iov: the array of memory regions to write data from + * @niov: the length of the @iov array + * @errp: pointer to a NULL-initialized error object + * + * Write data to the IO channel, reading it from the + * memory regions referenced by @iov. Each element + * in the @iov will be fully sent, before the next + * one is used. The @niov parameter specifies the + * total number of elements in @iov. + * + * The function will wait for all requested data + * to be written, yielding from the current coroutine + * if required. + * + * Returns: 0 if all bytes were written, or -1 on error + */ +int qio_channel_writev_all(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + Error **erp); + /** * qio_channel_readv: * @ioc: the channel object @@ -330,6 +382,44 @@ ssize_t qio_channel_write(QIOChannel *ioc, size_t buflen, Error **errp); +/** + * qio_channel_read_all: + * @ioc: the channel object + * @buf: the memory region to read data into + * @buflen: the number of bytes to @buf + * @errp: pointer to a NULL-initialized error object + * + * Reads @buflen bytes into @buf, possibly blocking or (if the + * channel is non-blocking) yielding from the current coroutine + * multiple times until the entire content is read. If end-of-file + * occurs it will return an error rather than a short-read. Otherwise + * behaves as qio_channel_read(). + * + * Returns: 0 if all bytes were read, or -1 on error + */ +int qio_channel_read_all(QIOChannel *ioc, + char *buf, + size_t buflen, + Error **errp); +/** + * qio_channel_write_all: + * @ioc: the channel object + * @buf: the memory region to write data into + * @buflen: the number of bytes to @buf + * @errp: pointer to a NULL-initialized error object + * + * Writes @buflen bytes from @buf, possibly blocking or (if the + * channel is non-blocking) yielding from the current coroutine + * multiple times until the entire content is written. Otherwise + * behaves as qio_channel_write(). + * + * Returns: 0 if all bytes were written, or -1 on error + */ +int qio_channel_write_all(QIOChannel *ioc, + const char *buf, + size_t buflen, + Error **errp); + /** * qio_channel_set_blocking: * @ioc: the channel object diff --git a/io/channel.c b/io/channel.c index 1cfb8b33a2..5e8c2f0a91 100644 --- a/io/channel.c +++ b/io/channel.c @@ -22,6 +22,7 @@ #include "io/channel.h" #include "qapi/error.h" #include "qemu/main-loop.h" +#include "qemu/iov.h" bool qio_channel_has_feature(QIOChannel *ioc, QIOChannelFeature feature) @@ -85,6 +86,79 @@ ssize_t qio_channel_writev_full(QIOChannel *ioc, } + +int qio_channel_readv_all(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + 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_readv(ioc, local_iov, nlocal_iov, errp); + if (len == QIO_CHANNEL_ERR_BLOCK) { + qio_channel_wait(ioc, G_IO_IN); + continue; + } else if (len < 0) { + goto cleanup; + } else if (len == 0) { + error_setg(errp, + "Unexpected end-of-file before all bytes were read"); + goto cleanup; + } + + iov_discard_front(&local_iov, &nlocal_iov, len); + } + + ret = 0; + + cleanup: + g_free(local_iov_head); + return ret; +} + +int qio_channel_writev_all(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + 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(ioc, local_iov, nlocal_iov, errp); + if (len == QIO_CHANNEL_ERR_BLOCK) { + qio_channel_wait(ioc, G_IO_OUT); + continue; + } + if (len < 0) { + goto cleanup; + } + + iov_discard_front(&local_iov, &nlocal_iov, len); + } + + ret = 0; + cleanup: + g_free(local_iov_head); + return ret; +} + ssize_t qio_channel_readv(QIOChannel *ioc, const struct iovec *iov, size_t niov, @@ -123,6 +197,26 @@ ssize_t qio_channel_write(QIOChannel *ioc, } +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) diff --git a/tests/io-channel-helpers.c b/tests/io-channel-helpers.c index 05e5579cf8..5430e1389d 100644 --- a/tests/io-channel-helpers.c +++ b/tests/io-channel-helpers.c @@ -21,6 +21,7 @@ #include "qemu/osdep.h" #include "io-channel-helpers.h" #include "qapi/error.h" +#include "qemu/iov.h" struct QIOChannelTest { QIOChannel *src; @@ -37,77 +38,17 @@ struct QIOChannelTest { }; -static void test_skip_iovec(struct iovec **iov, - size_t *niov, - size_t skip, - struct iovec *old) -{ - size_t offset = 0; - size_t i; - - for (i = 0; i < *niov; i++) { - if (skip < (*iov)[i].iov_len) { - old->iov_len = (*iov)[i].iov_len; - old->iov_base = (*iov)[i].iov_base; - - (*iov)[i].iov_len -= skip; - (*iov)[i].iov_base += skip; - break; - } else { - skip -= (*iov)[i].iov_len; - - if (i == 0 && old->iov_base) { - (*iov)[i].iov_len = old->iov_len; - (*iov)[i].iov_base = old->iov_base; - old->iov_len = 0; - old->iov_base = NULL; - } - - offset++; - } - } - - *iov = *iov + offset; - *niov -= offset; -} - - /* This thread sends all data using iovecs */ static gpointer test_io_thread_writer(gpointer opaque) { QIOChannelTest *data = opaque; - struct iovec *iov = data->inputv; - size_t niov = data->niov; - struct iovec old = { 0 }; qio_channel_set_blocking(data->src, data->blocking, NULL); - while (niov) { - ssize_t ret; - ret = qio_channel_writev(data->src, - iov, - niov, - &data->writeerr); - if (ret == QIO_CHANNEL_ERR_BLOCK) { - if (data->blocking) { - error_setg(&data->writeerr, - "Unexpected I/O blocking"); - break; - } else { - qio_channel_wait(data->src, - G_IO_OUT); - continue; - } - } else if (ret < 0) { - break; - } else if (ret == 0) { - error_setg(&data->writeerr, - "Unexpected zero length write"); - break; - } - - test_skip_iovec(&iov, &niov, ret, &old); - } + qio_channel_writev_all(data->src, + data->inputv, + data->niov, + &data->writeerr); return NULL; } @@ -117,38 +58,13 @@ static gpointer test_io_thread_writer(gpointer opaque) static gpointer test_io_thread_reader(gpointer opaque) { QIOChannelTest *data = opaque; - struct iovec *iov = data->outputv; - size_t niov = data->niov; - struct iovec old = { 0 }; qio_channel_set_blocking(data->dst, data->blocking, NULL); - while (niov) { - ssize_t ret; - - ret = qio_channel_readv(data->dst, - iov, - niov, - &data->readerr); - - if (ret == QIO_CHANNEL_ERR_BLOCK) { - if (data->blocking) { - error_setg(&data->readerr, - "Unexpected I/O blocking"); - break; - } else { - qio_channel_wait(data->dst, - G_IO_IN); - continue; - } - } else if (ret < 0) { - break; - } else if (ret == 0) { - break; - } - - test_skip_iovec(&iov, &niov, ret, &old); - } + qio_channel_readv_all(data->dst, + data->outputv, + data->niov, + &data->readerr); return NULL; }