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/*
* Helpers for getting linearized buffers from iov / filling buffers into iovs
*
* Copyright IBM, Corp. 2007, 2008
* Copyright (C) 2010 Red Hat, Inc.
*
* Author(s):
* Anthony Liguori <aliguori@us.ibm.com>
* Amit Shah <amit.shah@redhat.com>
* Michael Tokarev <mjt@tls.msk.ru>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#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)
{
size_t done;
unsigned int i;
for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
if (offset < iov[i].iov_len) {
size_t len = MIN(iov[i].iov_len - offset, bytes - done);
memcpy(iov[i].iov_base + offset, buf + done, len);
done += len;
offset = 0;
} else {
offset -= iov[i].iov_len;
}
}
assert(offset == 0);
return done;
}
size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt,
size_t offset, void *buf, size_t bytes)
{
size_t done;
unsigned int i;
for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
if (offset < iov[i].iov_len) {
size_t len = MIN(iov[i].iov_len - offset, bytes - done);
memcpy(buf + done, iov[i].iov_base + offset, len);
done += len;
offset = 0;
} else {
offset -= iov[i].iov_len;
}
}
assert(offset == 0);
return done;
}
size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt,
size_t offset, int fillc, size_t bytes)
{
size_t done;
unsigned int i;
for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
if (offset < iov[i].iov_len) {
size_t len = MIN(iov[i].iov_len - offset, bytes - done);
memset(iov[i].iov_base + offset, fillc, len);
done += len;
offset = 0;
} else {
offset -= iov[i].iov_len;
}
}
assert(offset == 0);
return done;
}
size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt)
{
size_t len;
unsigned int i;
len = 0;
for (i = 0; i < iov_cnt; i++) {
len += iov[i].iov_len;
}
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 = 0;
ssize_t ret = 0;
while (i < iov_cnt) {
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) {
ret = -1;
}
break;
}
i++;
}
return ret;
#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 */
if (bytes == 0) {
/* Catch the do-nothing case early, as otherwise we will pass an
* empty iovec to sendmsg/recvmsg(), and not all implementations
* accept this.
*/
return 0;
}
/* 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)
{
unsigned int i, v, b;
uint8_t *c;
c = iov[0].iov_base;
for (i = 0, v = 0, b = 0; b < limit; i++, b++) {
if (i == iov[v].iov_len) {
i = 0; v++;
if (v == iov_cnt) {
break;
}
c = iov[v].iov_base;
}
if ((b % 16) == 0) {
fprintf(fp, "%s: %04x:", prefix, b);
}
if ((b % 4) == 0) {
fprintf(fp, " ");
}
fprintf(fp, " %02x", c[i]);
if ((b % 16) == 15) {
fprintf(fp, "\n");
}
}
if ((b % 16) != 0) {
fprintf(fp, "\n");
}
}
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