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bug: correct read behavior #16

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merged 1 commit into from
Jun 3, 2024
Merged

bug: correct read behavior #16

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19 changes: 8 additions & 11 deletions src/iso15118/io/connection_plain.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -75,22 +75,19 @@ ReadResult ConnectionPlain::read(uint8_t* buf, size_t len) {
assert(connection_open);

const auto read_result = ::read(fd, buf, len);
if (read_result > 0) {
size_t bytes_read = read_result;
const auto would_block = (bytes_read < len);
return {would_block, bytes_read};
}
const auto did_block = (len > 0) and (read_result != len);

if (read_result == -1) {
// handle blocking read case
if (errno == EAGAIN) {
return {true, 0};
}
if (read_result >= 0) {
return {did_block, static_cast<size_t>(read_result)};
}

// should be an error
if (errno != EAGAIN) {
// in case the error is not due to blocking, log it
logf("ConnectionPlain::read failed with error code: %d", errno);
}

return {false, 0};
return {did_block, 0};
}

void ConnectionPlain::handle_connect() {
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21 changes: 12 additions & 9 deletions src/iso15118/session/iso.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -63,12 +63,13 @@ bool read_single_sdp_packet(io::IConnection& connection, io::SdpPacket& sdp_pack

assert(sdp_packet.get_state() == PacketState::EMPTY || sdp_packet.get_state() == PacketState::HEADER_READ);

// FIXME (aw): proper handling of case, where read returns 0!
auto result = connection.read(sdp_packet.get_current_buffer_pos(), sdp_packet.get_remaining_bytes_to_read());
sdp_packet.update_read_bytes(result.bytes_read);
const auto first_try =
connection.read(sdp_packet.get_current_buffer_pos(), sdp_packet.get_remaining_bytes_to_read());

if (result.would_block) {
// need more data!
sdp_packet.update_read_bytes(first_try.bytes_read);

if (first_try.would_block) {
// need more data for at least the header
return true;
}

Expand All @@ -83,11 +84,13 @@ bool read_single_sdp_packet(io::IConnection& connection, io::SdpPacket& sdp_pack
}

// header read successfully, try to read the rest
result = connection.read(sdp_packet.get_current_buffer_pos(), sdp_packet.get_remaining_bytes_to_read());
sdp_packet.update_read_bytes(result.bytes_read);
const auto second_try =
connection.read(sdp_packet.get_current_buffer_pos(), sdp_packet.get_remaining_bytes_to_read());

sdp_packet.update_read_bytes(second_try.bytes_read);

if (result.would_block) {
// need more data!
if (second_try.would_block) {
// need more data for the rest of the packet!
return true;
}

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