Use recv syscall instead of read in do_read_some()

Author: talawahtech

include/seastar/core/posix.hh

@@ -225,13 +225,13 @@ public:
  throw_system_error_on(r == -1, "read");
  return { size_t(r) };
  }
- std::optional<ssize_t> recv(void* buffer, size_t len, int flags) {
+ std::optional<size_t> recv(void* buffer, size_t len, int flags) {
  auto r = ::recv(_fd, buffer, len, flags);
  if (r == -1 && errno == EAGAIN) {
  return {};
  }
  throw_system_error_on(r == -1, "recv");
- return { ssize_t(r) };
+ return { size_t(r) };
  }
  std::optional<size_t> recvmsg(msghdr* mh, int flags) {
  auto r = ::recvmsg(_fd, mh, flags);

src/core/reactor.cc

@@ -258,7 +258,7 @@ future<> reactor::do_connect(pollable_fd_state& pfd, socket_address& sa) {
 future<size_t>
 reactor::do_read_some(pollable_fd_state& fd, void* buffer, size_t len) {
  return readable(fd).then([this, &fd, buffer, len] () mutable {
- auto r = fd.fd.read(buffer, len);
+ auto r = fd.fd.recv(buffer, len, 0);
  if (!r) {
  return do_read_some(fd, buffer, len);
  }
@@ -273,7 +273,7 @@ future<temporary_buffer<char>>
 reactor::do_read_some(pollable_fd_state& fd, internal::buffer_allocator* ba) {
  return fd.readable().then([this, &fd, ba] {
  auto buffer = ba->allocate_buffer();
- auto r = fd.fd.read(buffer.get_write(), buffer.size());
+ auto r = fd.fd.recv(buffer.get_write(), buffer.size(), 0);
  if (!r) {
  // Speculation failure, try again with real polling this time
  // Note we release the buffer and will reallocate it when poll