118 lines
2.1 KiB
C++
118 lines
2.1 KiB
C++
/*
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* \brief 'readv()' and 'writev()' implementations
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* \author Josef Soentgen
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* \author Christian Prochaska
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* \date 2012-04-10
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*/
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/*
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* Copyright (C) 2012-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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/* Genode includes */
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#include <base/lock.h>
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/* libc includes */
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#include <sys/uio.h>
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#include <limits.h>
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#include <unistd.h>
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#include <errno.h>
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#include <stdio.h>
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static Genode::Lock rw_lock;
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struct Read
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{
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ssize_t operator()(int fd, void *buf, size_t count)
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{
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return read(fd, buf, count);
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}
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};
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struct Write
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{
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ssize_t operator()(int fd, const void *buf, size_t count)
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{
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return write(fd, buf, count);
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}
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};
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template <typename Rw_func>
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static ssize_t readv_writev_impl(Rw_func rw_func, int fd, const struct iovec *iov, int iovcnt)
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{
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Genode::Lock_guard<Genode::Lock> rw_lock_guard(rw_lock);
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char *v;
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ssize_t bytes_transfered_total = 0;
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size_t v_len = 0;
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int i;
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if (iovcnt < 1 || iovcnt > IOV_MAX) {
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errno = EINVAL;
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return -1;
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}
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for (i = 0; i < iovcnt; i++)
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v_len += iov->iov_len;
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if (v_len > SSIZE_MAX) {
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errno = EINVAL;
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return -1;
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}
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while (iovcnt > 0) {
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v = static_cast<char *>(iov->iov_base);
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v_len = iov->iov_len;
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while (v_len > 0) {
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ssize_t bytes_transfered = rw_func(fd, v, v_len);
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if (bytes_transfered == -1)
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return -1;
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if (bytes_transfered == 0)
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return bytes_transfered_total;
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v_len -= bytes_transfered;
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v += bytes_transfered;
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bytes_transfered_total += bytes_transfered;
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}
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iov++;
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iovcnt--;
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}
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return bytes_transfered_total;
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}
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extern "C" ssize_t _readv(int fd, const struct iovec *iov, int iovcnt)
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{
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return readv_writev_impl(Read(), fd, iov, iovcnt);
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}
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extern "C" ssize_t readv(int fd, const struct iovec *iov, int iovcnt)
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{
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return _readv(fd, iov, iovcnt);
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}
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extern "C" ssize_t _writev(int fd, const struct iovec *iov, int iovcnt)
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{
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return readv_writev_impl(Write(), fd, iov, iovcnt);
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}
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extern "C" ssize_t writev(int fd, const struct iovec *iov, int iovcnt)
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{
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return _writev(fd, iov, iovcnt);
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}
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