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

#include "LinuxSyscalls/Syscalls.h"
#include "LinuxSyscalls/x32/Syscalls.h"
#include "LinuxSyscalls/x32/Types.h"

#include <algorithm>
#include <asm/posix_types.h>
#include <limits>
#include <linux/utsname.h>
#include <stdint.h>
#include <sys/resource.h>
#include <sys/sysinfo.h>
#include <sys/utsname.h>

#include <git_version.h>

namespace FEXCore::Core {
struct CpuStateFrame;
}

ARG_TO_STR(FEX::HLE::x32::compat_ptr<FEX::HLE::x32::rlimit32<true>>, "%lx")
ARG_TO_STR(FEX::HLE::x32::compat_ptr<FEX::HLE::x32::rlimit32<false>>, "%lx")

namespace FEX::HLE::x32 {
struct sysinfo32 {
  int32_t uptime;
  uint32_t loads[3];
  uint32_t totalram;
  uint32_t freeram;
  uint32_t sharedram;
  uint32_t bufferram;
  uint32_t totalswap;
  uint32_t freeswap;
  uint16_t procs;
  uint32_t totalhigh;
  uint32_t freehigh;
  uint32_t mem_unit;
  char _pad[8];
};

static_assert(sizeof(sysinfo32) == 64, "Needs to be 64bytes");

void RegisterInfo(FEX::HLE::SyscallHandler* Handler) {
  REGISTER_SYSCALL_IMPL_X32(oldolduname, [](FEXCore::Core::CpuStateFrame* Frame, struct oldold_utsname* buf) -> uint64_t {
    struct utsname Local {};

    FaultSafeUserMemAccess::VerifyIsWritable(buf, sizeof(*buf));

    memset(buf, 0, sizeof(*buf));
    if (::uname(&Local) == 0) {
      memcpy(buf->nodename, Local.nodename, __OLD_UTS_LEN);
    } else {
      strncpy(buf->nodename, "FEXCore", __OLD_UTS_LEN);
      LogMan::Msg::EFmt("Couldn't determine host nodename. Defaulting to '{}'", buf->nodename);
    }
    strncpy(buf->sysname, "Linux", __OLD_UTS_LEN);
    uint32_t GuestVersion = FEX::HLE::_SyscallHandler->GetGuestKernelVersion();
    snprintf(buf->release, __OLD_UTS_LEN, "%d.%d.%d", FEX::HLE::SyscallHandler::KernelMajor(GuestVersion),
             FEX::HLE::SyscallHandler::KernelMinor(GuestVersion), FEX::HLE::SyscallHandler::KernelPatch(GuestVersion));

    const char version[] = "#" GIT_DESCRIBE_STRING " SMP " __DATE__ " " __TIME__;
    strncpy(buf->version, version, __OLD_UTS_LEN);
    // Tell the guest that we are a 64bit kernel
    strncpy(buf->machine, "x86_64", __OLD_UTS_LEN);
    return 0;
  });

  REGISTER_SYSCALL_IMPL_X32(olduname, [](FEXCore::Core::CpuStateFrame* Frame, struct old_utsname* buf) -> uint64_t {
    struct utsname Local {};

    FaultSafeUserMemAccess::VerifyIsWritable(buf, sizeof(*buf));

    memset(buf, 0, sizeof(*buf));
    if (::uname(&Local) == 0) {
      memcpy(buf->nodename, Local.nodename, __NEW_UTS_LEN);
    } else {
      strncpy(buf->nodename, "FEXCore", __NEW_UTS_LEN);
      LogMan::Msg::EFmt("Couldn't determine host nodename. Defaulting to '{}'", buf->nodename);
    }
    strncpy(buf->sysname, "Linux", __NEW_UTS_LEN);
    uint32_t GuestVersion = FEX::HLE::_SyscallHandler->GetGuestKernelVersion();
    snprintf(buf->release, __NEW_UTS_LEN, "%d.%d.%d", FEX::HLE::SyscallHandler::KernelMajor(GuestVersion),
             FEX::HLE::SyscallHandler::KernelMinor(GuestVersion), FEX::HLE::SyscallHandler::KernelPatch(GuestVersion));

    const char version[] = "#" GIT_DESCRIBE_STRING " SMP " __DATE__ " " __TIME__;
    strncpy(buf->version, version, __NEW_UTS_LEN);
    // Tell the guest that we are a 64bit kernel
    strncpy(buf->machine, "x86_64", __NEW_UTS_LEN);
    return 0;
  });

  REGISTER_SYSCALL_IMPL_X32(
    getrlimit, [](FEXCore::Core::CpuStateFrame* Frame, int resource, compat_ptr<FEX::HLE::x32::rlimit32<true>> rlim) -> uint64_t {
      struct rlimit rlim64 {};
      uint64_t Result = ::getrlimit(resource, &rlim64);
      FaultSafeUserMemAccess::VerifyIsWritable(rlim, sizeof(*rlim));
      *rlim = rlim64;
      SYSCALL_ERRNO();
    });

  REGISTER_SYSCALL_IMPL_X32(
    ugetrlimit, [](FEXCore::Core::CpuStateFrame* Frame, int resource, compat_ptr<FEX::HLE::x32::rlimit32<false>> rlim) -> uint64_t {
      struct rlimit rlim64 {};
      uint64_t Result = ::getrlimit(resource, &rlim64);
      FaultSafeUserMemAccess::VerifyIsWritable(rlim, sizeof(*rlim));
      *rlim = rlim64;
      SYSCALL_ERRNO();
    });

  REGISTER_SYSCALL_IMPL_X32(
    setrlimit, [](FEXCore::Core::CpuStateFrame* Frame, int resource, const compat_ptr<FEX::HLE::x32::rlimit32<false>> rlim) -> uint64_t {
      struct rlimit rlim64 {};
      FaultSafeUserMemAccess::VerifyIsReadable(rlim, sizeof(*rlim));
      rlim64 = *rlim;
      uint64_t Result = ::setrlimit(resource, &rlim64);
      SYSCALL_ERRNO();
    });

  REGISTER_SYSCALL_IMPL_X32(sysinfo, [](FEXCore::Core::CpuStateFrame* Frame, struct sysinfo32* info) -> uint64_t {
    struct sysinfo Host {};
    uint64_t Result = ::sysinfo(&Host);
    if (Result != -1) {
      FaultSafeUserMemAccess::VerifyIsWritable(info, sizeof(*info));
#define Copy(x) \
  info->x = static_cast<decltype(info->x)>(std::min(Host.x, static_cast<decltype(Host.x)>(std::numeric_limits<decltype(info->x)>::max())));
      Copy(uptime);
      Copy(procs);
#define CopyShift(x) info->x = static_cast<decltype(info->x)>(Host.x >> ShiftAmount);

      info->loads[0] = std::min(Host.loads[0], static_cast<unsigned long>(std::numeric_limits<uint32_t>::max()));
      info->loads[1] = std::min(Host.loads[1], static_cast<unsigned long>(std::numeric_limits<uint32_t>::max()));
      info->loads[2] = std::min(Host.loads[2], static_cast<unsigned long>(std::numeric_limits<uint32_t>::max()));

      // If any result can't fit in to a uint32_t then we need to shift the mem_unit and all the members
      // Set the mem_unit to the pagesize
      uint32_t ShiftAmount {};
      if ((Host.totalram >> 32) != 0 || (Host.totalswap >> 32) != 0) {

        while (Host.mem_unit < 4096) {
          Host.mem_unit <<= 1;
          ++ShiftAmount;
        }
      }

      CopyShift(totalram);
      CopyShift(freeram);
      CopyShift(sharedram);
      CopyShift(bufferram);
      CopyShift(totalswap);
      CopyShift(freeswap);
      CopyShift(totalhigh);
      CopyShift(freehigh);
      Copy(mem_unit);
    }
    SYSCALL_ERRNO();
  });

  REGISTER_SYSCALL_IMPL_X32(getrusage, [](FEXCore::Core::CpuStateFrame* Frame, int who, rusage_32* usage) -> uint64_t {
    struct rusage usage64 = *usage;
    uint64_t Result = ::getrusage(who, &usage64);
    FaultSafeUserMemAccess::VerifyIsWritable(usage, sizeof(*usage));
    *usage = usage64;
    SYSCALL_ERRNO();
  });

  if (Handler->IsHostKernelVersionAtLeast(6, 8, 0)) {
    REGISTER_SYSCALL_IMPL_X32(map_shadow_stack, [](FEXCore::Core::CpuStateFrame* Frame, uint64_t addr, uint64_t size, uint32_t flags) -> uint64_t {
      // Claim that shadow stack isn't supported.
      return -EOPNOTSUPP;
    });
  } else {
    REGISTER_SYSCALL_IMPL_X32(map_shadow_stack, UnimplementedSyscallSafe);
  }
}
} // namespace FEX::HLE::x32