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qemu/1001-io-add-new-qio_channel_-readv-writev-read-write-_all.patch

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From 758d848ef10835108a75187d1a1a0418167f04b2 Mon Sep 17 00:00:00 2001
From: "Daniel P. Berrange" <berrange@redhat.com>
Date: Wed, 30 Aug 2017 14:53:59 +0100
Subject: [PATCH 01/15] 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 <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
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
@@ -269,6 +269,58 @@ ssize_t qio_channel_writev_full(QIOChannel *ioc,
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
* @iov: the array of memory regions to read data into
@@ -331,6 +383,44 @@ ssize_t qio_channel_write(QIOChannel *ioc,
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
* @enabled: the blocking flag state
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;
}
--
2.13.5
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