FEX-Emu--FEX/External/FEXCore/Source/Interface/HLE/Syscalls.cpp

#include "Common/MathUtils.h"

#include "Interface/Context/Context.h"
#include "Interface/Core/InternalThreadState.h"
#include "Interface/HLE/Syscalls.h"
#include "Interface/HLE/x64/Syscalls.h"
#include "Interface/HLE/x32/Syscalls.h"

#include "LogManager.h"

#include <FEXCore/Core/X86Enums.h>
#include <fcntl.h>
#include <limits.h>
#include <linux/futex.h>
#include <numaif.h>
#include <poll.h>
#include <sys/mman.h>
#include <sys/time.h>
#include <sys/random.h>
#include <sys/sysinfo.h>
#include <sys/utsname.h>
#include <sys/shm.h>
#include <sys/syscall.h>
#include <unistd.h>

constexpr uint64_t PAGE_SIZE = 4096;

#define BRK_BASE 0xd000'0000
#define BRK_SIZE 0x1000'0000

namespace FEXCore {
uint64_t SyscallHandler::HandleBRK(FEXCore::Core::InternalThreadState *Thread, void *Addr) {
  std::lock_guard<std::mutex> lk(MMapMutex);
  uint64_t Result;

  if (DataSpace == 0) {
    // XXX: We need to setup our default BRK space first
    DefaultProgramBreak(Thread, BRK_BASE);
  }

  if (Addr == nullptr) { // Just wants to get the location of the program break atm
    Result = DataSpace + DataSpaceSize;
  }
  else {
    // Allocating out data space
    uint64_t NewEnd = reinterpret_cast<uint64_t>(Addr);
    if (NewEnd < DataSpace) {
      // Not allowed to move brk end below original start
      // Set the size to zero
      DataSpaceSize = 0;
    }
    else {
      uint64_t NewSize = NewEnd - DataSpace;
      
      // make sure we don't overflow to TLS storage
      if (NewSize >= BRK_SIZE)
        return -ENOMEM;

      DataSpaceSize = NewSize;
    }
    Result = DataSpace + DataSpaceSize;
  }
  return Result;
}

uint64_t SyscallHandler::HandleMMAP(FEXCore::Core::InternalThreadState *Thread, void *addr, size_t length, int prot, int flags, int fd, off_t offset) {
  std::lock_guard<std::mutex> lk(MMapMutex);

  uint64_t Base = AlignDown(LastMMAP, PAGE_SIZE);
  uint64_t Size = AlignUp(length, PAGE_SIZE);
  if (length == 0) {
    return -EINVAL;
  }
  if ((LastMMAP + length) >= ENDMMAP) {
    LogMan::Msg::D("uhoh, mmap failed\n");
    return -ENOMEM;
  }

  if (flags & MAP_FIXED) {
    Base = reinterpret_cast<uint64_t>(addr);
    if (fd != -1) {
      auto Name = FM.FindFDName(fd);
      if (Name) {
        LogMan::Msg::D("Mapping File to [0x%lx, 0x%lx) -> '%s' -> %p", Base, Base + Size, Name->c_str(), Base);
      }
    }

    void *Res{};
    if (fd != -1) {
      Res = mmap(addr, length, prot, flags, fd, offset);
      if (Res == MAP_FAILED) {
        LogMan::Msg::A("Couldn't map file to %p\n", addr);
      }
    }
    else {
      Res = mmap(addr, length, prot, flags, fd, offset);
    }

    if (Res == MAP_FAILED) {
      return -errno;
    }

    return Base;
  }
  else {
    // If we are running unified memory then we want to be after our base
    // This makes code page loading less of a burden
    Base = CTX->MemoryMapper.GetBaseOffset<uint64_t>(LastMMAP);

    void *HostPtr = reinterpret_cast<void*>(Base);
    if (fd != -1) {
      auto Name = FM.FindFDName(fd);
      if (Name) {
        LogMan::Msg::D("Mapping File to [0x%lx, 0x%lx) -> '%s' -> %p", Base, Base + Size, Name->c_str(), HostPtr);
      }
    }

    void *Res{};
    if (fd != -1) {
      Res = mmap(HostPtr, length, prot, flags | MAP_FIXED, fd, offset);
      if (Res == MAP_FAILED) {
        perror(nullptr);
        LogMan::Msg::A("Couldn't map file to %p. error %d(%s)\n", HostPtr, errno, strerror(errno));
      }
      else {
      }
    }
    else {
      Res = mmap(HostPtr, length, prot, flags | MAP_FIXED, fd, offset);
    }

    if (Res == MAP_FAILED) {
      return -errno;
    }

    LastMMAP += Size;
    return Base;
  }
}

void SyscallHandler::DefaultProgramBreak(FEXCore::Core::InternalThreadState *Thread, uint64_t Addr) {
  DataSpaceSize = 0;
  // Just allocate 16MB of data memory past the default program break location at this point
  CTX->MapRegion(Thread, Addr, BRK_SIZE, true);

  Addr += CTX->MemoryMapper.GetBaseOffset<uint64_t>(0);

  DataSpace = Addr;
  DefaultProgramBreakAddress = Addr;
}

SyscallHandler::SyscallHandler(FEXCore::Context::Context *ctx)
  : FM {ctx}
  , CTX {ctx} {
}

SyscallHandler *CreateHandler(Context::OperatingMode Mode, FEXCore::Context::Context *ctx) {
  if (Mode == Context::MODE_64BIT) {
    return FEXCore::HLE::x64::CreateHandler(ctx);
  }
  else {
    return FEXCore::HLE::x32::CreateHandler(ctx);
  }
}

uint64_t HandleSyscall(SyscallHandler *Handler, FEXCore::Core::InternalThreadState *Thread, FEXCore::HLE::SyscallArguments *Args) {
  uint64_t Result{};
  Result = Handler->HandleSyscall(Thread, Args);
#ifdef DEBUG_STRACE
  Handler->Strace(Args, Result);
#endif
  return Result;
}

}