FEX-Emu--FEX/Source/Tools/LinuxEmulation/LinuxSyscalls/x32/Signals.cpp

// SPDX-License-Identifier: MIT
/*
$info$
tags: LinuxSyscalls|syscalls-x86-32
$end_info$
*/

#include "ArchHelpers/UContext.h"
#include "LinuxSyscalls/SignalDelegator.h"
#include "LinuxSyscalls/Syscalls.h"
#include "LinuxSyscalls/x64/Syscalls.h"
#include "LinuxSyscalls/x32/Syscalls.h"
#include "LinuxSyscalls/x32/Types.h"

#include <FEXCore/Core/SignalDelegator.h>
#include <errno.h>
#include <signal.h>
#include <stdint.h>
#include <sys/syscall.h>
#include <unistd.h>

#include <time.h>

namespace FEXCore::Core {
  struct CpuStateFrame;
}

ARG_TO_STR(FEX::HLE::x32::compat_ptr<FEXCore::x86::siginfo_t>, "%lx")

namespace FEX::HLE::x32 {
  void CopySigInfo(FEXCore::x86::siginfo_t *Info, siginfo_t const &Host) {
    // Copy the basic things first
    Info->si_signo = Host.si_signo;
    Info->si_errno = Host.si_errno;
    Info->si_code = Host.si_code;

    // Check si_code to determine how we need to interpret this
    if (Info->si_code == SI_TIMER) {
      // SI_TIMER means pid, uid, value
      Info->_sifields._timer.tid     = Host.si_timerid;
      Info->_sifields._timer.overrun = Host.si_overrun;
      Info->_sifields._timer.sigval.sival_int = Host.si_value.sival_int;
    }
    else {
      // Now we need to copy over the more complex things
      switch (Info->si_signo) {
        case SIGSEGV:
        case SIGBUS:
          // This is the address trying to be accessed, not the RIP
          Info->_sifields._sigfault.addr = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(Host.si_addr));
          break;
        case SIGFPE:
        case SIGILL:
          // Can't really give a real result here. This is the RIP causing a sigill or sigfpe
          // Claim at RIP 0 for now
          Info->_sifields._sigfault.addr = 0;
          break;
        case SIGCHLD:
          Info->_sifields._sigchld.pid    = Host.si_pid;
          Info->_sifields._sigchld.uid    = Host.si_uid;
          Info->_sifields._sigchld.status = Host.si_status;
          Info->_sifields._sigchld.utime  = Host.si_utime;
          Info->_sifields._sigchld.stime  = Host.si_stime;
          break;
        case SIGALRM:
        case SIGVTALRM:
          Info->_sifields._timer.tid              = Host.si_timerid;
          Info->_sifields._timer.overrun          = Host.si_overrun;
          Info->_sifields._timer.sigval.sival_int = Host.si_int;
          break;
        default:
          LogMan::Msg::EFmt("Unhandled siginfo_t for sigtimedwait: {}", Info->si_signo);
          break;
      }
    }
  }

  void RegisterSignals(FEX::HLE::SyscallHandler *Handler) {

    // Only gets the lower 32-bits of the signal mask
    REGISTER_SYSCALL_IMPL_X32(sgetmask, [](FEXCore::Core::CpuStateFrame *Frame) -> uint64_t {
      uint64_t Set{};
      FEX::HLE::_SyscallHandler->GetSignalDelegator()->GuestSigProcMask(0, nullptr, &Set);
      return Set & ~0U;
    });

    // Only controls the lower 32-bits of the signal mask
    // Blocks the upper 32-bits
    REGISTER_SYSCALL_IMPL_X32(ssetmask, [](FEXCore::Core::CpuStateFrame *Frame, uint32_t New) -> uint64_t {
      uint64_t Set{};
      uint64_t NewSet = (~0ULL << 32) | New;
      FEX::HLE::_SyscallHandler->GetSignalDelegator()->GuestSigProcMask(SIG_SETMASK, &NewSet, &Set);
      return Set & ~0U;
    });

    // Only masks the lower 32-bits of the signal mask
    // The upper 32-bits are still active (unmasked) and can signal the program
    REGISTER_SYSCALL_IMPL_X32(sigsuspend, [](FEXCore::Core::CpuStateFrame *Frame, uint32_t Mask) -> uint64_t {
      uint64_t Mask64 = Mask;
      return FEX::HLE::_SyscallHandler->GetSignalDelegator()->GuestSigSuspend(&Mask64, 8);
    });

    REGISTER_SYSCALL_IMPL_X32(sigpending, [](FEXCore::Core::CpuStateFrame *Frame, compat_old_sigset_t *set) -> uint64_t {
      uint64_t HostSet{};
      uint64_t Result = FEX::HLE::_SyscallHandler->GetSignalDelegator()->GuestSigPending(&HostSet, 8);
      if (Result == 0) {
        // This old interface only returns the lower signals
        *set = HostSet & ~0U;
      }
      return Result;
    });

    REGISTER_SYSCALL_IMPL_X32(signal, [](FEXCore::Core::CpuStateFrame *Frame, int signum, uint32_t handler) -> uint64_t {
      GuestSigAction newact{};
      GuestSigAction oldact{};
      newact.sigaction_handler.handler = reinterpret_cast<decltype(newact.sigaction_handler.handler)>(handler);
      FEX::HLE::_SyscallHandler->GetSignalDelegator()->RegisterGuestSignalHandler(signum, &newact, &oldact);
      return static_cast<uint32_t>(reinterpret_cast<uint64_t>(oldact.sigaction_handler.handler));
    });

    REGISTER_SYSCALL_IMPL_X32(sigaction, [](FEXCore::Core::CpuStateFrame *Frame, int signum, const OldGuestSigAction_32 *act, OldGuestSigAction_32 *oldact) -> uint64_t {
      GuestSigAction *act64_p{};
      GuestSigAction *old64_p{};

      GuestSigAction act64{};
      if (act) {
        act64 = *act;
        act64_p = &act64;
      }
      GuestSigAction old64{};

      if (oldact) {
        old64_p = &old64;
      }

      uint64_t Result = FEX::HLE::_SyscallHandler->GetSignalDelegator()->RegisterGuestSignalHandler(signum, act64_p, old64_p);
      if (Result == 0 && oldact) {
        *oldact = old64;
      }

      return Result;
    });

    REGISTER_SYSCALL_IMPL_X32(rt_sigaction, [](FEXCore::Core::CpuStateFrame *Frame, int signum, const GuestSigAction_32 *act, GuestSigAction_32 *oldact, size_t sigsetsize) -> uint64_t {
      if (sigsetsize != 8) {
        return -EINVAL;
      }

      GuestSigAction *act64_p{};
      GuestSigAction *old64_p{};

      GuestSigAction act64{};
      if (act) {
        act64 = *act;
        act64_p = &act64;
      }
      GuestSigAction old64{};

      if (oldact) {
        old64_p = &old64;
      }

      uint64_t Result = FEX::HLE::_SyscallHandler->GetSignalDelegator()->RegisterGuestSignalHandler(signum, act64_p, old64_p);
      if (Result == 0 && oldact) {
        *oldact = old64;
      }

      return Result;
    });

    REGISTER_SYSCALL_IMPL_X32(rt_sigtimedwait, [](FEXCore::Core::CpuStateFrame *Frame, uint64_t *set, compat_ptr<FEXCore::x86::siginfo_t> info, const struct timespec32* timeout, size_t sigsetsize) -> uint64_t {
      struct timespec* timeout_ptr{};
      struct timespec tp64{};
      if (timeout) {
        tp64 = *timeout;
        timeout_ptr = &tp64;
      }

      siginfo_t HostInfo{};
      uint64_t Result = FEX::HLE::_SyscallHandler->GetSignalDelegator()->GuestSigTimedWait(set, &HostInfo, timeout_ptr, sigsetsize);
      if (Result != -1) {
        // We need to translate the 64-bit siginfo_t to 32-bit siginfo_t
        CopySigInfo(info, HostInfo);
      }
      return Result;
    });


    REGISTER_SYSCALL_IMPL_X32(rt_sigtimedwait_time64, [](FEXCore::Core::CpuStateFrame *Frame, uint64_t *set, compat_ptr<FEXCore::x86::siginfo_t> info, const struct timespec* timeout, size_t sigsetsize) -> uint64_t {
      siginfo_t HostInfo{};
      uint64_t Result = FEX::HLE::_SyscallHandler->GetSignalDelegator()->GuestSigTimedWait(set, &HostInfo, timeout, sigsetsize);
      if (Result != -1) {
        // We need to translate the 64-bit siginfo_t to 32-bit siginfo_t
        CopySigInfo(info, HostInfo);
      }
      return Result;
    });

    if (Handler->IsHostKernelVersionAtLeast(5, 1, 0)) {
      REGISTER_SYSCALL_IMPL_X32(pidfd_send_signal, [](FEXCore::Core::CpuStateFrame *Frame, int pidfd, int sig, compat_ptr<FEXCore::x86::siginfo_t> info, unsigned int flags) -> uint64_t {
        siginfo_t *InfoHost_ptr{};
        siginfo_t InfoHost{};
        if (info) {
          InfoHost = *info;
          InfoHost_ptr = &InfoHost;
        }

        uint64_t Result = ::syscall(SYSCALL_DEF(pidfd_send_signal), pidfd, sig, InfoHost_ptr, flags);
        SYSCALL_ERRNO();
      });
    }
    else {
      REGISTER_SYSCALL_IMPL_X32(pidfd_send_signal, UnimplementedSyscallSafe);
    }

    REGISTER_SYSCALL_IMPL_X32_PASS(rt_sigqueueinfo, [](FEXCore::Core::CpuStateFrame *Frame, pid_t pid, int sig, compat_ptr<FEXCore::x86::siginfo_t> info) -> uint64_t {
      siginfo_t info64{};
      siginfo_t *info64_p{};

      if (info) {
        info64_p = &info64;
      }

      uint64_t Result = ::syscall(SYSCALL_DEF(rt_sigqueueinfo), pid, sig, info64_p);
      SYSCALL_ERRNO();
    });

    REGISTER_SYSCALL_IMPL_X32_PASS(rt_tgsigqueueinfo, [](FEXCore::Core::CpuStateFrame *Frame, pid_t tgid, pid_t tid, int sig, compat_ptr<FEXCore::x86::siginfo_t> info) -> uint64_t {
      siginfo_t info64{};
      siginfo_t *info64_p{};

      if (info) {
        info64_p = &info64;
      }

      uint64_t Result = ::syscall(SYSCALL_DEF(rt_tgsigqueueinfo), tgid, tid, sig, info64_p);
      SYSCALL_ERRNO();
    });
  }
}