FEX-Emu--FEX/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 "LogManager.h"

#include <FEXCore/Core/X86Enums.h>
#include <sys/mman.h>

constexpr uint64_t PAGE_SIZE = 4096;

namespace FEXCore {
void SyscallHandler::DefaultProgramBreak(FEXCore::Core::InternalThreadState *Thread, uint64_t Addr) {
  DataSpaceSize = 0;
  DataSpace = Addr;
  DefaultProgramBreakAddress = Addr;

  // Just allocate 1GB of data memory past the default program break location at this point
  CTX->MapRegion(Thread, Addr, 0x1000'0000);
}

uint64_t SyscallHandler::HandleSyscall(FEXCore::Core::InternalThreadState *Thread, FEXCore::HLE::SyscallArguments *Args) {
  uint64_t Result = 0;

  LogMan::Msg::D("Syscall: %d", Args->Argument[0]);

  switch (Args->Argument[0]) {
  case SYSCALL_UNAME: {
    struct _utsname {
      char sysname[65];
      char nodename[65];
      char release[65];
      char version[65];
      char machine[65];
    };
    _utsname *Local = CTX->MemoryMapper.GetPointer<_utsname*>(Args->Argument[1]);
    strcpy(Local->sysname, "Linux");
    strcpy(Local->nodename, "FEXCore");
    strcpy(Local->release, "5.0.0");
    strcpy(Local->version, "#1");
    strcpy(Local->machine, "x86_64");
    Result = 0;
  break;
  }
  // Memory management
  case SYSCALL_BRK: {
    LogMan::Msg::D("\tBRK: 0x%lx - 0x%lx", Args->Argument[1], DataSpace);
    if (Args->Argument[1] == 0) { // Just wants to get the location of the program break atm
      Result = DataSpace + DataSpaceSize;
    }
    else {
      // Allocating out data space
      uint64_t NewEnd = Args->Argument[1];
      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;
        DataSpaceSize = NewSize;
      }
      Result = DataSpace + DataSpaceSize;
    }
  break;
  }
  case SYSCALL_MMAP: {
    LogMan::Msg::D("\tMMAP(<addr> %p, <length> 0x%lx, <prot>%d, <flags>0x%x, <fd>%d, <offset>0x%lx)",
        Args->Argument[1], Args->Argument[2],
        Args->Argument[3], Args->Argument[4],
        Args->Argument[5], Args->Argument[6]);
    int Flags = Args->Argument[4];
    int GuestFD = Args->Argument[5];
    int HostFD = -1;

    if (GuestFD != -1) {
      HostFD = FM.FindHostFD(GuestFD);
    }

    uint64_t Base = AlignDown(LastMMAP, PAGE_SIZE);
    uint64_t Size = AlignUp(Args->Argument[2], PAGE_SIZE);
    uint64_t FileSizeToUse = Args->Argument[2];
    uint64_t Prot = Args->Argument[3];

#ifdef DEBUG_MMAP
    FileSizeToUse = Size;
    Prot = PROT_READ | PROT_WRITE | PROT_EXEC;
#endif

    if (Flags & MAP_FIXED) {
      Base = Args->Argument[1];
      void *HostPtr = CTX->MemoryMapper.GetPointer<void*>(Base);
      if (!HostPtr) {
        HostPtr = CTX->MapRegion(Thread, Base, Size, true);
      }
      else {
        LogMan::Msg::D("\tMapping Fixed pointer in already mapped space: 0x%lx -> %p", Base, HostPtr);
      }

      if (HostFD != -1) {
#ifdef DEBUG_MMAP
        // We are a file. Screw you I'm going to just memcpy you in to place
        void *FileMem = mmap(nullptr, FileSizeToUse, Prot, MAP_PRIVATE, HostFD, Args->Argument[6]);
        if (FileMem == MAP_FAILED) {
          LogMan::Msg::A("Couldn't map file to %p\n", HostPtr);
        }

        memcpy(HostPtr, FileMem, FileSizeToUse);
        munmap(FileMem, Size);
#else
        void *FileMem = mmap(HostPtr, FileSizeToUse, Prot, MAP_PRIVATE | MAP_FIXED, HostFD, Args->Argument[6]);
        if (FileMem == MAP_FAILED) {
          LogMan::Msg::A("Couldn't map file to %p\n", HostPtr);
        }
#endif
      }
      else {
        LogMan::Throw::A(Args->Argument[6] == 0, "Don't understand a fixed offset mmap");
      }

      Result = Base;
    }
    else {
      // XXX: MMAP should map memory regions for all threads
      void *HostPtr = CTX->MapRegion(Thread, Base, Size, true);

      if (HostFD != -1) {
#ifdef DEBUG_MMAP
        // We are a file. Screw you I'm going to just memcpy you in to place
        void *FileMem = mmap(nullptr, FileSizeToUse, Prot, MAP_PRIVATE, HostFD, Args->Argument[6]);
        if (FileMem == MAP_FAILED) {
          LogMan::Msg::A("Couldn't map file to %p\n", HostPtr);
        }

        memcpy(HostPtr, FileMem, FileSizeToUse);
        munmap(FileMem, Size);
#else
        void *FileMem = mmap(HostPtr, FileSizeToUse, Prot, MAP_PRIVATE | MAP_FIXED, HostFD, Args->Argument[6]);
        if (FileMem == MAP_FAILED) {
          LogMan::Msg::A("Couldn't map file to %p\n", HostPtr);
        }
#endif
      }

      LastMMAP += Size;
      Result = Base;
    }
  break;
  }
  case SYSCALL_MPROTECT: {
    LogMan::Msg::D("\tMPROTECT: 0x%x, 0x%lx, 0x%lx", Args->Argument[1], Args->Argument[2], Args->Argument[3]);
    void *HostPtr = CTX->MemoryMapper.GetPointer<void*>(Args->Argument[1]);

    Result = mprotect(HostPtr, Args->Argument[2], Args->Argument[3]);
  break;
  }
  case SYSCALL_ARCH_PRCTL: {
    LogMan::Msg::D("\tPRTCL: 0x%x: 0x%lx", Args->Argument[1], Args->Argument[2]);
    switch (Args->Argument[1]) {
    case 0x1001: // ARCH_SET_GS
      Thread->State.State.gs = Args->Argument[2];
    break;
    case 0x1002: // ARCH_SET_FS
      Thread->State.State.fs = Args->Argument[2];
    break;
    case 0x1003: // ARCH_GET_FS
      *CTX->MemoryMapper.GetPointer<uint64_t*>(Args->Argument[2]) = Thread->State.State.fs;
    break;
    case 0x1004: // ARCH_GET_GS
      *CTX->MemoryMapper.GetPointer<uint64_t*>(Args->Argument[2]) = Thread->State.State.gs;
    break;
    default:
      LogMan::Msg::E("Unknown prctl: 0x%x", Args->Argument[1]);
      CTX->ShouldStop = true;
    break;
    }
    Result = 0;
  break;
  }
  // Thread management
  case SYSCALL_GETUID:
    Result = Thread->State.ThreadManager.GetUID();
  break;
  case SYSCALL_GETGID:
    Result = Thread->State.ThreadManager.GetGID();
  break;
  case SYSCALL_GETEUID:
    Result = Thread->State.ThreadManager.GetEUID();
  break;
  case SYSCALL_GETEGID:
    Result = Thread->State.ThreadManager.GetEGID();
  break;
  case SYSCALL_GETTID:
    Result = Thread->State.ThreadManager.GetTID();
  break;
  case SYSCALL_GETPID:
    Result = Thread->State.ThreadManager.GetPID();
  break;
  case SYSCALL_EXIT:
    LogMan::Msg::D("Thread exit with: %zd\n", Args->Argument[1]);
    Thread->State.RunningEvents.ShouldStop = true;
  break;
  case SYSCALL_WAIT4:
    LogMan::Msg::I("wait4(%lx,\n\t%lx,\n\t%lx,\n\t%lx)",
      Args->Argument[1],
      Args->Argument[2],
      Args->Argument[3],
      Args->Argument[4]);
  break;

  // Futexes
  case SYSCALL_FUTEX: {

  // 0 : uaddr
  // 1 : op
  // 2: val
  // 3: utime
  // 4: uaddr2
  // 5: val3
  LogMan::Msg::I("futex(%lx,\n\t%lx,\n\t%lx,\n\t%lx,\n\t%lx,\n\t%lx)",
      Args->Argument[1],
      Args->Argument[2],
      Args->Argument[3],
      Args->Argument[4],
      Args->Argument[5],
      Args->Argument[6]);

  uint8_t Command = Args->Argument[2] & 0xF;
  Result = 0;
  switch (Command) {
  case 0: { // WAIT
    LogMan::Throw::A(!Args->Argument[4], "Can't handle timed futexes");
    Futex *futex = new Futex{}; // XXX: Definitely a memory leak. When should we free this?
    futex->Addr = CTX->MemoryMapper.GetPointer<std::atomic<uint32_t>*>(Args->Argument[1]);
    futex->Val = Args->Argument[3];
    EmplaceFutex(Args->Argument[1], futex);
    {
      std::unique_lock<std::mutex> lk(futex->Mutex);
      futex->cv.wait(lk, [futex] { return futex->Addr->load() != futex->Val; });
    }
  break;
  }
  case 1: { // WAKE
    Futex *futex = GetFutex(Args->Argument[1]);
    if (!futex) {
      Result = 0;
      break;
    }
    for (uint64_t i = 0; i < Args->Argument[3]; ++i)
      futex->cv.notify_one();
  break;
  }
  default:
    LogMan::Msg::A("Unknown futex command");
  break;
  }
  break;
  }
  case SYSCALL_CLONE: {
    // 0: clone_flags
    // 1: New SP
    // 2: parent tidptr
    // 3: child tidptr
    // 4: TLS
    LogMan::Msg::I("clone(%lx,\n\t%lx,\n\t%lx,\n\t%lx,\n\t%lx,\n\t%lx,\n\t%lx)",
        Args->Argument[0],
        Args->Argument[1],
        Args->Argument[2],
        Args->Argument[3],
        Args->Argument[4],
        Args->Argument[5]);
    uint32_t Flags = Args->Argument[1];
    uint64_t NewSP = Args->Argument[2];
    uint64_t ParentTID = Args->Argument[3];
    uint64_t ChildTID = Args->Argument[4];
    uint64_t NewTLS = Args->Argument[5];
#define FLAGPRINT(x, y) if (Flags & (y)) LogMan::Msg::I("\tFlag: " #x)
    FLAGPRINT(CSIGNAL,              0x000000FF);
    FLAGPRINT(CLONE_VM,             0x00000100);
    FLAGPRINT(CLONE_FS,             0x00000200);
    FLAGPRINT(CLONE_FILES,          0x00000400);
    FLAGPRINT(CLONE_SIGHAND,        0x00000800);
    FLAGPRINT(CLONE_PTRACE,         0x00002000);
    FLAGPRINT(CLONE_VFORK,          0x00004000);
    FLAGPRINT(CLONE_PARENT,         0x00008000);
    FLAGPRINT(CLONE_THREAD,         0x00010000);
    FLAGPRINT(CLONE_NEWNS,          0x00020000);
    FLAGPRINT(CLONE_SYSVSEM,        0x00040000);
    FLAGPRINT(CLONE_SETTLS,         0x00080000);
    FLAGPRINT(CLONE_PARENT_SETTID,  0x00100000);
    FLAGPRINT(CLONE_CHILD_CLEARTID, 0x00200000);
    FLAGPRINT(CLONE_DETACHED,       0x00400000);
    FLAGPRINT(CLONE_UNTRACED,       0x00800000);
    FLAGPRINT(CLONE_CHILD_SETTID,   0x01000000);
    FLAGPRINT(CLONE_NEWCGROUP,      0x02000000);
    FLAGPRINT(CLONE_NEWUTS,         0x04000000);
    FLAGPRINT(CLONE_NEWIPC,         0x08000000);
    FLAGPRINT(CLONE_NEWUSER,        0x10000000);
    FLAGPRINT(CLONE_NEWPID,         0x20000000);
    FLAGPRINT(CLONE_NEWNET,         0x40000000);
    FLAGPRINT(CLONE_IO,             0x80000000);

    FEXCore::Core::CPUState NewThreadState{};
    // Clone copies the parent thread's state
    memcpy(&NewThreadState, &Thread->State.State, sizeof(FEXCore::Core::CPUState));

    NewThreadState.gregs[FEXCore::X86State::REG_RAX] = 0;
    NewThreadState.gregs[FEXCore::X86State::REG_RBX] = 0;
    NewThreadState.gregs[FEXCore::X86State::REG_RBP] = 0;
    NewThreadState.gregs[FEXCore::X86State::REG_RSP] = NewSP;
    NewThreadState.fs = NewTLS;

    // Set us to start just after the syscall instruction
    NewThreadState.rip += 2;

    auto NewThread = CTX->CreateThread(&NewThreadState, ParentTID, ChildTID);
    CTX->CopyMemoryMapping(Thread, NewThread);

    // Sets the child TID to pointer in ParentTID
    if (Flags & CLONE_PARENT_SETTID) {
      uint64_t *TIDPtr = CTX->MemoryMapper.GetPointer<uint64_t*>(ParentTID);
      TIDPtr[0] = NewThread->State.ThreadManager.GetTID();
    }

    // Sets the child TID to the pointer in ChildTID
    if (Flags & CLONE_CHILD_SETTID) {
      uint64_t *TIDPtr = CTX->MemoryMapper.GetPointer<uint64_t*>(ChildTID);
      TIDPtr[0] = NewThread->State.ThreadManager.GetTID();
    }

    // When the thread exits, clear the child thread ID at ChildTID
    // Additionally wakeup a futex at that address
    // Address /may/ be changed with SET_TID_ADDRESS syscall
    if (Flags & CLONE_CHILD_CLEARTID) {
    }

    CTX->InitializeThread(NewThread);

    // Actually start the thread
    CTX->RunThread(NewThread);

    // Return the new threads TID
    Result = NewThread->State.ThreadManager.GetTID();
  break;
  }
  // File management
  case SYSCALL_READ:
    Result = FM.Read(Args->Argument[1],
        CTX->MemoryMapper.GetPointer(Args->Argument[2]),
        Args->Argument[3]);
  break;
  case SYSCALL_WRITE:
    Result = FM.Write(Args->Argument[1],
        CTX->MemoryMapper.GetPointer(Args->Argument[2]),
        Args->Argument[3]);
  break;
  case SYSCALL_OPEN:
    Result = FM.Open(CTX->MemoryMapper.GetPointer<char const*>(Args->Argument[1]),
        Args->Argument[2],
        Args->Argument[3]);
  break;
  case SYSCALL_CLOSE:
    Result = FM.Close(Args->Argument[1]);
  break;
  case SYSCALL_STAT:
    Result = FM.Stat(CTX->MemoryMapper.GetPointer<char const*>(Args->Argument[1]),
        CTX->MemoryMapper.GetPointer(Args->Argument[2]));
  break;
  case SYSCALL_FSTAT:
    Result = FM.Fstat(Args->Argument[1],
        CTX->MemoryMapper.GetPointer(Args->Argument[2]));
  break;
  case SYSCALL_LSEEK:
    Result = FM.Lseek(Args->Argument[1],
        Args->Argument[2],
        Args->Argument[3]);
  break;
  case SYSCALL_WRITEV:
    Result = FM.Writev(Args->Argument[1],
        CTX->MemoryMapper.GetPointer(Args->Argument[2]),
        Args->Argument[3]);
  break;
  case SYSCALL_ACCESS:
  Result = FM.Access(
      CTX->MemoryMapper.GetPointer<const char*>(Args->Argument[1]),
      Args->Argument[2]);
  break;
  case SYSCALL_READLINK:
    Result = FM.Readlink(
      CTX->MemoryMapper.GetPointer<const char*>(Args->Argument[1]),
      CTX->MemoryMapper.GetPointer<char*>(Args->Argument[2]),
      Args->Argument[3]);
  break;
  case SYSCALL_OPENAT:
    Result = FM.Openat(
      Args->Argument[1],
      CTX->MemoryMapper.GetPointer<const char*>(Args->Argument[2]),
      Args->Argument[3],
      Args->Argument[4]);
  break;

  case SYSCALL_CLOCK_GETTIME: {
    timespec *ClockResult = CTX->MemoryMapper.GetPointer<timespec*>(Args->Argument[2]);
    Result = clock_gettime(Args->Argument[1], ClockResult);
    // XXX: Debug
    // memset(ClockResult, 0, sizeof(timespec));
  }
  break;
  case SYSCALL_NANOSLEEP: {
    timespec const* req = CTX->MemoryMapper.GetPointer<timespec const*>(Args->Argument[1]);
    timespec *rem = CTX->MemoryMapper.GetPointer<timespec*>(Args->Argument[2]);
    Result = nanosleep(req, rem);
  break;
  }
  case SYSCALL_SET_TID_ADDRESS: {
    Thread->State.ThreadManager.child_tid = Args->Argument[1];
    Result = Thread->State.ThreadManager.GetTID();
  break;
  }
  case SYSCALL_SET_ROBUST_LIST: {
    Thread->State.ThreadManager.robust_list_head = Args->Argument[1];
    Result = 0;
  break;
  }
  case SYSCALL_PRLIMIT64: {
  LogMan::Throw::A(Args->Argument[3] == 0, "Guest trying to set limit for %d", Args->Argument[2]);
  struct rlimit {
    uint64_t rlim_cur;
    uint64_t rlim_max;
  };
  switch (Args->Argument[2]) {
  case 3: { // Stack limits
    rlimit *old_limit = CTX->MemoryMapper.GetPointer<rlimit*>(Args->Argument[3]);
    // Default size
    old_limit->rlim_cur = 8 * 1024;
    old_limit->rlim_max = ~0ULL;
  break;
  }
  default: LogMan::Msg::A("Unknown PRLimit: %d", Args->Argument[2]);
  }
  Result = 0;

  break;
  }
  // Currently unhandled
  // Return fake result
  case SYSCALL_RT_SIGACTION:
  case SYSCALL_RT_SIGPROCMASK:
  case SYSCALL_EXIT_GROUP:
  case SYSCALL_TGKILL:
  case SYSCALL_MUNMAP:
    Result = 0;
  break;
  default:
    Result = -1;
    LogMan::Msg::A("Unknown syscall: %d", Args->Argument[0]);
  break;
  }

  return Result;
}
}