/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. */

#include "paddle/platform/dynload/dynamic_loader.h"
#include <dlfcn.h>
#include <memory>
#include <mutex>
#include <string>
#include "gflags/gflags.h"
#include "glog/logging.h"
#include "paddle/platform/enforce.h"

DEFINE_string(cudnn_dir, "",
              "Specify path for loading libcudnn.so. For instance, "
              "/usr/local/cudnn/lib. If empty [default], dlopen "
              "will search cudnn from LD_LIBRARY_PATH");

DEFINE_string(cuda_dir, "",
              "Specify path for loading cuda library, such as libcublas, "
              "libcurand. For instance, /usr/local/cuda/lib64. If default, "
              "dlopen will search cuda from LD_LIBRARY_PATH");

DEFINE_string(warpctc_dir, "", "Specify path for loading libwarpctc.so.");

DEFINE_string(lapack_dir, "", "Specify path for loading liblapack.so.");

namespace paddle {
namespace platform {
namespace dynload {

static inline std::string join(const std::string& part1,
                               const std::string& part2) {
  // directory separator
  const char sep = '/';
  if (!part2.empty() && part2.front() == sep) {
    return part2;
  }
  std::string ret;
  ret.reserve(part1.size() + part2.size() + 1);
  ret = part1;
  if (!ret.empty() && ret.back() != sep) {
    ret += sep;
  }
  ret += part2;
  return ret;
}

static inline void GetDsoHandleFromDefaultPath(std::string& dso_path,
                                               void** dso_handle,
                                               int dynload_flags) {
  VLOG(3) << "Try to find library: " << dso_path
          << " from default system path.";
  // default search from LD_LIBRARY_PATH/DYLD_LIBRARY_PATH
  *dso_handle = dlopen(dso_path.c_str(), dynload_flags);

// DYLD_LIBRARY_PATH is disabled after Mac OS 10.11 to
// bring System Integrity Projection (SIP), if dso_handle
// is null, search from default package path in Mac OS.
#if defined(__APPLE__) || defined(__OSX__)
  if (nullptr == *dso_handle) {
    dso_path = join("/usr/local/cuda/lib/", dso_path);
    *dso_handle = dlopen(dso_path.c_str(), dynload_flags);
    if (nullptr == *dso_handle) {
      if (dso_path == "libcudnn.dylib") {
        PADDLE_ENFORCE(true,
                       "Note: [Recommend] copy cudnn into /usr/local/cuda/ \n "
                       "For instance, sudo tar -xzf "
                       "cudnn-7.5-osx-x64-v5.0-ga.tgz -C /usr/local \n sudo "
                       "chmod a+r /usr/local/cuda/include/cudnn.h "
                       "/usr/local/cuda/lib/libcudnn*");
      }
    }
  }
#endif
}

static inline void GetDsoHandleFromSearchPath(const std::string& search_root,
                                              const std::string& dso_name,
                                              void** dso_handle) {
  int dynload_flags = RTLD_LAZY | RTLD_LOCAL;
  *dso_handle = nullptr;

  std::string dlPath = dso_name;
  if (search_root.empty()) {
    GetDsoHandleFromDefaultPath(dlPath, dso_handle, dynload_flags);
  } else {
    // search xxx.so from custom path
    dlPath = join(search_root, dso_name);
    *dso_handle = dlopen(dlPath.c_str(), dynload_flags);
    // if not found, search from default path
    if (nullptr == *dso_handle) {
      LOG(WARNING) << "Failed to find dynamic library: " << dlPath << " ("
                   << dlerror() << ")";
      dlPath = dso_name;
      GetDsoHandleFromDefaultPath(dlPath, dso_handle, dynload_flags);
    }
  }
  PADDLE_ENFORCE(nullptr != *dso_handle,
                 "Failed to find dynamic library: %s ( %s ) \n Please specify "
                 "its path correctly using following ways: \n Method. set "
                 "environment variable LD_LIBRARY_PATH on Linux or "
                 "DYLD_LIBRARY_PATH on Mac OS. \n For instance, issue command: "
                 "export LD_LIBRARY_PATH=... \n Note: After Mac OS 10.11, "
                 "using the DYLD_LIBRARY_PATH is impossible unless System "
                 "Integrity Protection (SIP) is disabled.",
                 dlPath, dlerror());
}

void GetCublasDsoHandle(void** dso_handle) {
#if defined(__APPLE__) || defined(__OSX__)
  GetDsoHandleFromSearchPath(FLAGS_cuda_dir, "libcublas.dylib", dso_handle);
#else
  GetDsoHandleFromSearchPath(FLAGS_cuda_dir, "libcublas.so", dso_handle);
#endif
}

void GetCudnnDsoHandle(void** dso_handle) {
#if defined(__APPLE__) || defined(__OSX__)
  GetDsoHandleFromSearchPath(FLAGS_cudnn_dir, "libcudnn.dylib", dso_handle);
#else
  GetDsoHandleFromSearchPath(FLAGS_cudnn_dir, "libcudnn.so", dso_handle);
#endif
}

void GetCurandDsoHandle(void** dso_handle) {
#if defined(__APPLE__) || defined(__OSX__)
  GetDsoHandleFromSearchPath(FLAGS_cuda_dir, "libcurand.dylib", dso_handle);
#else
  GetDsoHandleFromSearchPath(FLAGS_cuda_dir, "libcurand.so", dso_handle);
#endif
}

void GetWarpCTCDsoHandle(void** dso_handle) {
#if defined(__APPLE__) || defined(__OSX__)
  GetDsoHandleFromSearchPath(FLAGS_warpctc_dir, "libwarpctc.dylib", dso_handle);
#else
  GetDsoHandleFromSearchPath(FLAGS_warpctc_dir, "libwarpctc.so", dso_handle);
#endif
}

void GetLapackDsoHandle(void** dso_handle) {
#if defined(__APPLE__) || defined(__OSX__)
  GetDsoHandleFromSearchPath(FLAGS_lapack_dir, "liblapacke.dylib", dso_handle);
#else
  GetDsoHandleFromSearchPath(FLAGS_lapack_dir, "liblapacke.so", dso_handle);
#endif
}

}  // namespace dynload
}  // namespace platform
}  // namespace paddle
