RASCSI/cpp/piscsi/piscsi_service.cpp

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//---------------------------------------------------------------------------
//
// SCSI Target Emulator PiSCSI
// for Raspberry Pi
//
// Copyright (C) 2022-2023 Uwe Seimet
//
//---------------------------------------------------------------------------
#include "shared/piscsi_util.h"
#include "shared/piscsi_exceptions.h"
#include "command_context.h"
#include "piscsi_service.h"
#include <spdlog/spdlog.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <csignal>
#include <cassert>
using namespace piscsi_util;
string PiscsiService::Init(const callback& cb, int port)
{
assert(service_socket == -1);
if (port <= 0 || port > 65535) {
return "Invalid port number " + to_string(port);
}
service_socket = socket(PF_INET, SOCK_STREAM, 0);
if (service_socket == -1) {
return "Unable to create service socket: " + string(strerror(errno));
}
if (const int yes = 1; setsockopt(service_socket, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0) {
Stop();
return "Can't reuse address";
}
sockaddr_in server = {};
server.sin_family = PF_INET;
server.sin_port = htons((uint16_t)port);
server.sin_addr.s_addr = INADDR_ANY;
if (bind(service_socket, reinterpret_cast<const sockaddr *>(&server), sizeof(sockaddr_in)) < 0) { //NOSONAR bit_cast is not supported by the bullseye compiler
Stop();
return "Port " + to_string(port) + " is in use, is piscsi already running?";
}
if (listen(service_socket, 2) == -1) {
Stop();
return "Can't listen to service socket: " + string(strerror(errno));
}
execute = cb;
return "";
}
void PiscsiService::Start()
{
assert(service_socket != -1);
service_thread = jthread([this] () { Execute(); } );
}
void PiscsiService::Stop()
{
assert(service_socket != -1);
shutdown(service_socket, SHUT_RD);
close(service_socket);
service_socket = -1;
}
void PiscsiService::Execute() const
{
#ifdef __linux__
// Run this thread with very low priority
sched_param schedparam = { .sched_priority = 0 };
sched_setscheduler(0, SCHED_IDLE, &schedparam);
#endif
// TODO Accept more than one command instead of closing the socket after a single command
while (service_socket != -1) {
const int fd = accept(service_socket, nullptr, nullptr);
if (fd != -1) {
ExecuteCommand(fd);
close(fd);
}
}
}
void PiscsiService::ExecuteCommand(int fd) const
{
CommandContext context(fd);
try {
if (context.ReadCommand()) {
execute(context);
}
}
catch(const io_exception& e) {
spdlog::warn(e.what());
// Try to return an error message (this may fail if the exception was caused when returning the actual result)
PbResult result;
result.set_msg(e.what());
try {
context.WriteResult(result);
}
catch(const io_exception&) { //NOSONAR Not handled on purpose
// Ignore
}
}
}