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[Qemu-devel] [PATCHv5 11/11] rewrite iov_send_recv() and move it to iov.
From: |
Michael Tokarev |
Subject: |
[Qemu-devel] [PATCHv5 11/11] rewrite iov_send_recv() and move it to iov.c |
Date: |
Tue, 20 Mar 2012 01:22:19 +0400 |
Make it much more understandable, add a missing
iov_cnt argument (number of iovs in the iov), and
add comments to it.
The new implementation has been extensively tested
by splitting a large buffer into many small
randomly-sized chunks, sending it over socket to
another, slow process and verifying the receiving
data is the same.
Also add a unit test for iov_send_recv(), sending/
receiving data between two processes over a socketpair
using random vectors and random sizes.
Signed-off-by: Michael Tokarev <address@hidden>
---
cutils.c | 83 -----------------------------------------
iov.c | 103 +++++++++++++++++++++++++++++++++++++++++++++++++++
iov.h | 15 ++++---
qemu-coroutine-io.c | 2 +-
test-iov.c | 103 +++++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 216 insertions(+), 90 deletions(-)
diff --git a/cutils.c b/cutils.c
index cb6f638..e2bc1b8 100644
--- a/cutils.c
+++ b/cutils.c
@@ -375,86 +375,3 @@ int qemu_parse_fd(const char *param)
}
return fd;
}
-
-ssize_t iov_send_recv(int sockfd, struct iovec *iov,
- size_t offset, size_t bytes,
- bool do_sendv)
-{
- int iovlen;
- ssize_t ret;
- size_t diff;
- struct iovec *last_iov;
-
- /* last_iov is inclusive, so count from one. */
- iovlen = 1;
- last_iov = iov;
- bytes += offset;
-
- while (last_iov->iov_len < bytes) {
- bytes -= last_iov->iov_len;
-
- last_iov++;
- iovlen++;
- }
-
- diff = last_iov->iov_len - bytes;
- last_iov->iov_len -= diff;
-
- while (iov->iov_len <= offset) {
- offset -= iov->iov_len;
-
- iov++;
- iovlen--;
- }
-
- iov->iov_base = (char *) iov->iov_base + offset;
- iov->iov_len -= offset;
-
- {
-#if defined CONFIG_IOVEC && defined CONFIG_POSIX
- struct msghdr msg;
- memset(&msg, 0, sizeof(msg));
- msg.msg_iov = iov;
- msg.msg_iovlen = iovlen;
-
- do {
- if (do_sendv) {
- ret = sendmsg(sockfd, &msg, 0);
- } else {
- ret = recvmsg(sockfd, &msg, 0);
- }
- } while (ret == -1 && errno == EINTR);
-#else
- struct iovec *p = iov;
- ret = 0;
- while (iovlen > 0) {
- int rc;
- if (do_sendv) {
- rc = send(sockfd, p->iov_base, p->iov_len, 0);
- } else {
- rc = qemu_recv(sockfd, p->iov_base, p->iov_len, 0);
- }
- if (rc == -1) {
- if (errno == EINTR) {
- continue;
- }
- if (ret == 0) {
- ret = -1;
- }
- break;
- }
- if (rc == 0) {
- break;
- }
- ret += rc;
- iovlen--, p++;
- }
-#endif
- }
-
- /* Undo the changes above */
- iov->iov_base = (char *) iov->iov_base - offset;
- iov->iov_len += offset;
- last_iov->iov_len += diff;
- return ret;
-}
diff --git a/iov.c b/iov.c
index 9657d28..7cc08f0 100644
--- a/iov.c
+++ b/iov.c
@@ -18,6 +18,14 @@
#include "iov.h"
+#ifdef _WIN32
+# include <windows.h>
+# include <winsock2.h>
+#else
+# include <sys/types.h>
+# include <sys/socket.h>
+#endif
+
size_t iov_from_buf(struct iovec *iov, unsigned int iov_cnt,
size_t offset, const void *buf, size_t bytes)
{
@@ -87,6 +95,101 @@ size_t iov_size(const struct iovec *iov, const unsigned int
iov_cnt)
return len;
}
+/* helper function for iov_send_recv() */
+static ssize_t
+do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send)
+{
+#if defined CONFIG_IOVEC && defined CONFIG_POSIX
+ ssize_t ret;
+ struct msghdr msg;
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_iov = iov;
+ msg.msg_iovlen = iov_cnt;
+ do {
+ ret = do_send
+ ? sendmsg(sockfd, &msg, 0)
+ : recvmsg(sockfd, &msg, 0);
+ } while (ret < 0 && errno == EINTR);
+ return ret;
+#else
+ /* else send piece-by-piece */
+ /*XXX Note: windows has WSASend() and WSARecv() */
+ unsigned i;
+ size_t count = 0;
+ for (i = 0; i < iov_cnt; ++i) {
+ ssize_t r = do_send
+ ? send(sockfd, iov[i].iov_base, iov[i].iov_len, 0)
+ : recv(sockfd, iov[i].iov_base, iov[i].iov_len, 0);
+ if (r > 0) {
+ ret += r;
+ } else if (!r) {
+ break;
+ } else if (errno == EINTR) {
+ continue;
+ } else {
+ /* else it is some "other" error,
+ * only return if there was no data processed. */
+ if (ret == 0) {
+ return -1;
+ }
+ break;
+ }
+ }
+ return count;
+#endif
+}
+
+ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
+ size_t offset, size_t bytes,
+ bool do_send)
+{
+ ssize_t ret;
+ unsigned si, ei; /* start and end indexes */
+
+ /* Find the start position, skipping `offset' bytes:
+ * first, skip all full-sized vector elements, */
+ for (si = 0; si < iov_cnt && offset >= iov[si].iov_len; ++si) {
+ offset -= iov[si].iov_len;
+ }
+ if (offset) {
+ assert(si < iov_cnt);
+ /* second, skip `offset' bytes from the (now) first element,
+ * undo it on exit */
+ iov[si].iov_base += offset;
+ iov[si].iov_len -= offset;
+ }
+ /* Find the end position skipping `bytes' bytes: */
+ /* first, skip all full-sized elements */
+ for (ei = si; ei < iov_cnt && iov[ei].iov_len <= bytes; ++ei) {
+ bytes -= iov[ei].iov_len;
+ }
+ if (bytes) {
+ /* second, fixup the last element, and remember
+ * the length we've cut from the end of it in `bytes' */
+ size_t tail;
+ assert(ei < iov_cnt);
+ assert(iov[ei].iov_len > bytes);
+ tail = iov[ei].iov_len - bytes;
+ iov[ei].iov_len = bytes;
+ bytes = tail; /* bytes is now equal to the tail size */
+ ++ei;
+ }
+
+ ret = do_send_recv(sockfd, iov + si, ei - si, do_send);
+
+ /* Undo the changes above */
+ if (offset) {
+ iov[si].iov_base -= offset;
+ iov[si].iov_len += offset;
+ }
+ if (bytes) {
+ iov[ei-1].iov_len += bytes;
+ }
+
+ return ret;
+}
+
+
void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt,
FILE *fp, const char *prefix, size_t limit)
{
diff --git a/iov.h b/iov.h
index 9b6a883..381f37a 100644
--- a/iov.h
+++ b/iov.h
@@ -60,7 +60,7 @@ size_t iov_memset(const struct iovec *iov, const unsigned int
iov_cnt,
* `offset' bytes in the beginning of iovec buffer are skipped and
* next `bytes' bytes are used, which must be within data of iovec.
*
- * r = iov_send_recv(sockfd, iov, offset, bytes, true);
+ * r = iov_send_recv(sockfd, iov, iovcnt, offset, bytes, true);
*
* is logically equivalent to
*
@@ -68,13 +68,16 @@ size_t iov_memset(const struct iovec *iov, const unsigned
int iov_cnt,
* iov_to_buf(iov, iovcnt, offset, buf, bytes);
* r = send(sockfd, buf, bytes, 0);
* free(buf);
+ *
+ * For iov_send_recv() _whole_ area being sent or received
+ * should be within the iovec, not only beginning of it.
*/
-ssize_t iov_send_recv(int sockfd, struct iovec *iov,
+ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
size_t offset, size_t bytes, bool do_send);
-#define iov_recv(sockfd, iov, offset, bytes) \
- iov_send_recv(sockfd, iov, offset, bytes, false)
-#define iov_send(sockfd, iov, offset, bytes) \
- iov_send_recv(sockfd, iov, offset, bytes, true)
+#define iov_recv(sockfd, iov, iov_cnt, offset, bytes) \
+ iov_send_recv(sockfd, iov, iov_cnt, offset, bytes, false)
+#define iov_send(sockfd, iov, iov_cnt, offset, bytes) \
+ iov_send_recv(sockfd, iov, iov_cnt, offset, bytes, true)
/**
* Produce a text hexdump of iovec `iov' with `iov_cnt' number of elements
diff --git a/qemu-coroutine-io.c b/qemu-coroutine-io.c
index 6693c78..5734965 100644
--- a/qemu-coroutine-io.c
+++ b/qemu-coroutine-io.c
@@ -34,7 +34,7 @@ qemu_co_sendv_recvv(int sockfd, struct iovec *iov, unsigned
iov_cnt,
size_t done = 0;
ssize_t ret;
while (done < bytes) {
- ret = iov_send_recv(sockfd, iov,
+ ret = iov_send_recv(sockfd, iov, iov_cnt,
offset + done, bytes - done, do_send);
if (ret > 0) {
done += ret;
diff --git a/test-iov.c b/test-iov.c
index 5f82296..285d98b 100644
--- a/test-iov.c
+++ b/test-iov.c
@@ -1,6 +1,7 @@
#include <glib.h>
#include "qemu-common.h"
#include "iov.h"
+#include "qemu_socket.h"
/* create a randomly-sized iovec with random vectors */
static void iov_random(struct iovec **iovp, unsigned *iov_cntp)
@@ -144,10 +145,112 @@ static void test_to_from_buf(void)
}
}
+static void test_io(void)
+{
+ int sv[2];
+ int r;
+ unsigned i, j, k, s, t;
+ fd_set fds;
+ unsigned niov;
+ struct iovec *iov, *siov;
+ unsigned char *buf;
+ size_t sz;
+
+ iov_random(&iov, &niov);
+ sz = iov_size(iov, niov);
+ buf = g_malloc(sz);
+ for (i = 0; i < sz; ++i) {
+ buf[i] = i & 255;
+ }
+ iov_from_buf(iov, niov, 0, buf, sz);
+
+ siov = g_malloc(sizeof(*iov) * niov);
+ memcpy(siov, iov, sizeof(*iov) * niov);
+
+ if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) < 0) {
+ perror("socketpair");
+ exit(1);
+ }
+
+ FD_ZERO(&fds);
+
+ t = 0;
+ if (fork() == 0) {
+ /* writer */
+
+ close(sv[0]);
+ FD_SET(sv[1], &fds);
+ fcntl(sv[1], F_SETFL, O_RDWR|O_NONBLOCK);
+ r = g_test_rand_int_range(sz / 2, sz);
+ setsockopt(sv[1], SOL_SOCKET, SO_SNDBUF, &r, sizeof(r));
+
+ for (i = 0; i <= sz; ++i) {
+ for (j = i; j <= sz; ++j) {
+ k = i;
+ do {
+ s = g_test_rand_int_range(0, j - k + 1);
+ r = iov_send(sv[1], iov, niov, k, s);
+ g_assert(memcmp(iov, siov, sizeof(*iov)*niov) == 0);
+ if (r >= 0) {
+ k += r;
+ t += r;
+ usleep(g_test_rand_int_range(0, 30));
+ } else if (errno == EAGAIN) {
+ select(sv[1]+1, NULL, &fds, NULL, NULL);
+ continue;
+ } else {
+ perror("send");
+ exit(1);
+ }
+ } while(k < j);
+ }
+ }
+ exit(0);
+
+ } else {
+ /* reader & verifier */
+
+ close(sv[1]);
+ FD_SET(sv[0], &fds);
+ fcntl(sv[0], F_SETFL, O_RDWR|O_NONBLOCK);
+ r = g_test_rand_int_range(sz / 2, sz);
+ setsockopt(sv[0], SOL_SOCKET, SO_RCVBUF, &r, sizeof(r));
+ usleep(500000);
+
+ for (i = 0; i <= sz; ++i) {
+ for (j = i; j <= sz; ++j) {
+ k = i;
+ iov_memset(iov, niov, 0, j & 255, -1);
+ do {
+ s = g_test_rand_int_range(0, j - k + 1);
+ r = iov_recv(sv[0], iov, niov, k, s);
+ g_assert(memcmp(iov, siov, sizeof(*iov)*niov) == 0);
+ if (r > 0) {
+ k += r;
+ t += r;
+ } else if (!r) {
+ if (s) {
+ break;
+ }
+ } else if (errno == EAGAIN) {
+ select(sv[0]+1, &fds, NULL, NULL, NULL);
+ continue;
+ } else {
+ perror("recv");
+ exit(1);
+ }
+ } while(k < j);
+ test_iov_bytes(iov, niov, i, j - i);
+ }
+ }
+ }
+}
+
int main(int argc, char **argv)
{
g_test_init(&argc, &argv, NULL);
g_test_rand_int();
g_test_add_func("/basic/iov/from-to-buf", test_to_from_buf);
+ g_test_add_func("/basic/iov/io", test_io);
return g_test_run();
}
--
1.7.9.1
- [Qemu-devel] [PATCHv5 06/11] consolidate qemu_iovec_copy() and qemu_iovec_concat() and make them consistent, (continued)
- [Qemu-devel] [PATCHv5 06/11] consolidate qemu_iovec_copy() and qemu_iovec_concat() and make them consistent, Michael Tokarev, 2012/03/16
- [Qemu-devel] [PATCHv5 01/11] virtio-serial-bus: use correct lengths in control_out() message, Michael Tokarev, 2012/03/16
- [Qemu-devel] [PATCHv5 08/11] rename qemu_sendv to iov_send, change proto and move declarations to iov.h, Michael Tokarev, 2012/03/16
- [Qemu-devel] [PATCHv5 11/11] rewrite iov_send_recv() and move it to iov.c, Michael Tokarev, 2012/03/16
- [Qemu-devel] [PATCHv5 00/11] cleanup/consolidate iovec functions, Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 10/11] cleanup qemu_co_sendv(), qemu_co_recvv() and friends, Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 05/11] allow qemu_iovec_from_buffer() to specify offset from which to start copying, Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 02/11] change iov_* function prototypes to be more appropriate, Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 08/11] rename qemu_sendv to iov_send, change proto and move declarations to iov.h, Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 04/11] consolidate qemu_iovec_memset{, _skip}() into single function and use existing iov_memset(), Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 11/11] rewrite iov_send_recv() and move it to iov.c,
Michael Tokarev <=
- Re: [Qemu-devel] [PATCHv5 00/11] cleanup/consolidate iovec functions, Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 01/11] virtio-serial-bus: use correct lengths in control_out() message, Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 03/11] rewrite iov_* functions, Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 06/11] consolidate qemu_iovec_copy() and qemu_iovec_concat() and make them consistent, Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 07/11] change qemu_iovec_to_buf() to match other to, from_buf functions, Michael Tokarev, 2012/03/19
- [Qemu-devel] [PATCHv5 09/11] export iov_send_recv() and use it in iov_send() and iov_recv(), Michael Tokarev, 2012/03/19