//===- llvm/Support/Unix/Path.inc - Unix Path Implementation ----*- C++ -*-===//

//

//                     The LLVM Compiler Infrastructure

//

// This file is distributed under the University of Illinois Open Source

// License. See LICENSE.TXT for details.

//

//===----------------------------------------------------------------------===//

//

// This file implements the Unix specific implementation of the Path API.

//

//===----------------------------------------------------------------------===//

//===----------------------------------------------------------------------===//

//=== WARNING: Implementation here must contain only generic UNIX code that

//===          is guaranteed to work on *all* UNIX variants.

//===----------------------------------------------------------------------===//

#include "Unix.h"

#include <limits.h>

#include <stdio.h>

#if HAVE_SYS_STAT_H

#include <sys/stat.h>

#endif

#if HAVE_FCNTL_H

#include <fcntl.h>

#endif

#ifdef HAVE_SYS_MMAN_H

#include <sys/mman.h>

#endif

#if HAVE_DIRENT_H

# include <dirent.h>

# define NAMLEN(dirent) strlen((dirent)->d_name)

#else

# define dirent direct

# define NAMLEN(dirent) (dirent)->d_namlen

# if HAVE_SYS_NDIR_H

#  include <sys/ndir.h>

# endif

# if HAVE_SYS_DIR_H

#  include <sys/dir.h>

# endif

# if HAVE_NDIR_H

#  include <ndir.h>

# endif

#endif

#ifdef __APPLE__

#include <mach-o/dyld.h>

#endif

// Both stdio.h and cstdio are included via different pathes and

// stdcxx's cstdio doesn't include stdio.h, so it doesn't #undef the macros

// either.

#undef ferror

#undef feof

// For GNU Hurd

#if defined(__GNU__) && !defined(PATH_MAX)

# define PATH_MAX 4096

#endif

using namespace llvm_ks;

namespace llvm_ks {

namespace sys  {

namespace fs {

#if defined(__FreeBSD__) || defined (__NetBSD__) || defined(__Bitrig__) || \

    defined(__OpenBSD__) || defined(__minix) || defined(__FreeBSD_kernel__) || \

    defined(__linux__) || defined(__CYGWIN__) || defined(__DragonFly__)

static int

test_dir(char ret[PATH_MAX], const char *dir, const char *bin)

{  

  struct stat sb;

  char fullpath[PATH_MAX];

  snprintf(fullpath, PATH_MAX, "%s/%s", dir, bin);

  if (!realpath(fullpath, ret))

    return 1;

  if (stat(fullpath, &sb) != 0)

    return 1;

  return 0;

}

static char *

getprogpath(char ret[PATH_MAX], const char *bin)

{

  char *pv, *s, *t;

  /* First approach: absolute path. */

  if (bin[0] == '/') {

    if (test_dir(ret, "/", bin) == 0)

      return ret;

    return nullptr;

  }

  /* Second approach: relative path. */

  if (strchr(bin, '/')) {

    char cwd[PATH_MAX];

    if (!getcwd(cwd, PATH_MAX))

      return nullptr;

    if (test_dir(ret, cwd, bin) == 0)

      return ret;

    return nullptr;

  }

  /* Third approach: $PATH */

  if ((pv = getenv("PATH")) == nullptr)

    return nullptr;

  s = pv = strdup(pv);

  if (!pv)

    return nullptr;

  while ((t = strsep(&s, ":")) != nullptr) {

    if (test_dir(ret, t, bin) == 0) {

      free(pv);

      return ret;

    }

  }

  free(pv);

  return nullptr;

}

#endif // __FreeBSD__ || __NetBSD__ || __FreeBSD_kernel__

/// GetMainExecutable - Return the path to the main executable, given the

/// value of argv[0] from program startup.

std::string getMainExecutable(const char *argv0, void *MainAddr) {

#if defined(__APPLE__)

  // On OS X the executable path is saved to the stack by dyld. Reading it

  // from there is much faster than calling dladdr, especially for large

  // binaries with symbols.

  char exe_path[MAXPATHLEN];

  uint32_t size = sizeof(exe_path);

  if (_NSGetExecutablePath(exe_path, &size) == 0) {

    char link_path[MAXPATHLEN];

    if (realpath(exe_path, link_path))

      return link_path;

  }

#elif defined(__FreeBSD__) || defined (__NetBSD__) || defined(__Bitrig__) || \

      defined(__OpenBSD__) || defined(__minix) || defined(__DragonFly__) || \

      defined(__FreeBSD_kernel__)

  char exe_path[PATH_MAX];

  if (getprogpath(exe_path, argv0) != NULL)

    return exe_path;

#elif defined(__linux__) || defined(__CYGWIN__)

  char exe_path[MAXPATHLEN];

  StringRef aPath("/proc/self/exe");

  if (sys::fs::exists(aPath)) {

      // /proc is not always mounted under Linux (chroot for example).

      ssize_t len = readlink(aPath.str().c_str(), exe_path, sizeof(exe_path));

      if (len >= 0)

          return std::string(exe_path, len);

  } else {

      // Fall back to the classical detection.

      if (getprogpath(exe_path, argv0))

        return exe_path;

  }

#elif defined(HAVE_DLFCN_H)

  // Use dladdr to get executable path if available.

  Dl_info DLInfo;

  int err = dladdr(MainAddr, &DLInfo);

  if (err == 0)

    return "";

  // If the filename is a symlink, we need to resolve and return the location of

  // the actual executable.

  char link_path[MAXPATHLEN];

  if (realpath(DLInfo.dli_fname, link_path))

    return link_path;

#else

#error GetMainExecutable is not implemented on this host yet.

#endif

  return "";

}

UniqueID file_status::getUniqueID() const {

  return UniqueID(fs_st_dev, fs_st_ino);

}

std::error_code current_path(SmallVectorImpl<char> &result) {

  result.clear();

  const char *pwd = ::getenv("PWD");

  llvm_ks::sys::fs::file_status PWDStatus, DotStatus;

  if (pwd && llvm_ks::sys::path::is_absolute(pwd) &&

      !llvm_ks::sys::fs::status(pwd, PWDStatus) &&

      !llvm_ks::sys::fs::status(".", DotStatus) &&

      PWDStatus.getUniqueID() == DotStatus.getUniqueID()) {

    result.append(pwd, pwd + strlen(pwd));

    return std::error_code();

  }

#ifdef MAXPATHLEN

  result.reserve(MAXPATHLEN);

#else

// For GNU Hurd

  result.reserve(1024);

#endif

  while (true) {

    if (::getcwd(result.data(), result.capacity()) == nullptr) {

      // See if there was a real error.

      if (errno != ENOMEM)

        return std::error_code(errno, std::generic_category());

      // Otherwise there just wasn't enough space.

      result.reserve(result.capacity() * 2);

    } else

      break;

  }

  result.set_size(strlen(result.data()));

  return std::error_code();

}

std::error_code create_directory(const Twine &path, bool IgnoreExisting,

                                 perms Perms) {

  SmallString<128> path_storage;

  StringRef p = path.toNullTerminatedStringRef(path_storage);

  if (::mkdir(p.begin(), Perms) == -1) {

    if (errno != EEXIST || !IgnoreExisting)

      return std::error_code(errno, std::generic_category());

  }

  return std::error_code();

}

// Note that we are using symbolic link because hard links are not supported by

// all filesystems (SMB doesn't).

std::error_code create_link(const Twine &to, const Twine &from) {

  // Get arguments.

  SmallString<128> from_storage;

  SmallString<128> to_storage;

  StringRef f = from.toNullTerminatedStringRef(from_storage);

  StringRef t = to.toNullTerminatedStringRef(to_storage);

  if (::symlink(t.begin(), f.begin()) == -1)

    return std::error_code(errno, std::generic_category());

  return std::error_code();

}

std::error_code remove(const Twine &path, bool IgnoreNonExisting) {

  SmallString<128> path_storage;

  StringRef p = path.toNullTerminatedStringRef(path_storage);

  struct stat buf;

  if (lstat(p.begin(), &buf) != 0) {

    if (errno != ENOENT || !IgnoreNonExisting)

      return std::error_code(errno, std::generic_category());

    return std::error_code();

  }

  // Note: this check catches strange situations. In all cases, LLVM should

  // only be involved in the creation and deletion of regular files.  This

  // check ensures that what we're trying to erase is a regular file. It

  // effectively prevents LLVM from erasing things like /dev/null, any block

  // special file, or other things that aren't "regular" files.

  if (!S_ISREG(buf.st_mode) && !S_ISDIR(buf.st_mode) && !S_ISLNK(buf.st_mode))

    return make_error_code(errc::operation_not_permitted);

  if (::remove(p.begin()) == -1) {

    if (errno != ENOENT || !IgnoreNonExisting)

      return std::error_code(errno, std::generic_category());

  }

  return std::error_code();

}

std::error_code rename(const Twine &from, const Twine &to) {

  // Get arguments.

  SmallString<128> from_storage;

  SmallString<128> to_storage;

  StringRef f = from.toNullTerminatedStringRef(from_storage);

  StringRef t = to.toNullTerminatedStringRef(to_storage);

  if (::rename(f.begin(), t.begin()) == -1)

    return std::error_code(errno, std::generic_category());

  return std::error_code();

}

std::error_code resize_file(int FD, uint64_t Size) {

  if (::ftruncate(FD, Size) == -1)

    return std::error_code(errno, std::generic_category());

  return std::error_code();

}

static int convertAccessMode(AccessMode Mode) {

  switch (Mode) {

  case AccessMode::Exist:

    return F_OK;

  case AccessMode::Write:

    return W_OK;

  case AccessMode::Execute:

    return R_OK | X_OK; // scripts also need R_OK.

  }

  llvm_unreachable("invalid enum");

}

std::error_code access(const Twine &Path, AccessMode Mode) {

  SmallString<128> PathStorage;

  StringRef P = Path.toNullTerminatedStringRef(PathStorage);

  if (::access(P.begin(), convertAccessMode(Mode)) == -1)

    return std::error_code(errno, std::generic_category());

  if (Mode == AccessMode::Execute) {

    // Don't say that directories are executable.

    struct stat buf;

    if (0 != stat(P.begin(), &buf))

      return errc::permission_denied;

    if (!S_ISREG(buf.st_mode))

      return errc::permission_denied;

  }

  return std::error_code();

}

bool can_execute(const Twine &Path) {

  return !access(Path, AccessMode::Execute);

}

bool equivalent(file_status A, file_status B) {

  assert(status_known(A) && status_known(B));

  return A.fs_st_dev == B.fs_st_dev &&

         A.fs_st_ino == B.fs_st_ino;

}

std::error_code equivalent(const Twine &A, const Twine &B, bool &result) {

  file_status fsA, fsB;

  if (std::error_code ec = status(A, fsA))

    return ec;

  if (std::error_code ec = status(B, fsB))

    return ec;

  result = equivalent(fsA, fsB);

  return std::error_code();

}

static std::error_code fillStatus(int StatRet, const struct stat &Status,

                             file_status &Result) {

  if (StatRet != 0) {

    std::error_code ec(errno, std::generic_category());

    if (ec == errc::no_such_file_or_directory)

      Result = file_status(file_type::file_not_found);

    else

      Result = file_status(file_type::status_error);

    return ec;

  }

  file_type Type = file_type::type_unknown;

  if (S_ISDIR(Status.st_mode))

    Type = file_type::directory_file;

  else if (S_ISREG(Status.st_mode))

    Type = file_type::regular_file;

  else if (S_ISBLK(Status.st_mode))

    Type = file_type::block_file;

  else if (S_ISCHR(Status.st_mode))

    Type = file_type::character_file;

  else if (S_ISFIFO(Status.st_mode))

    Type = file_type::fifo_file;

  else if (S_ISSOCK(Status.st_mode))

    Type = file_type::socket_file;

  perms Perms = static_cast<perms>(Status.st_mode);

  Result =

      file_status(Type, Perms, Status.st_dev, Status.st_ino, Status.st_mtime,

                  Status.st_uid, Status.st_gid, Status.st_size);

  return std::error_code();

}

std::error_code status(const Twine &Path, file_status &Result) {

  SmallString<128> PathStorage;

  StringRef P = Path.toNullTerminatedStringRef(PathStorage);

  struct stat Status;

  int StatRet = ::stat(P.begin(), &Status);

  return fillStatus(StatRet, Status, Result);

}

std::error_code status(int FD, file_status &Result) {

  struct stat Status;

  int StatRet = ::fstat(FD, &Status);

  return fillStatus(StatRet, Status, Result);

}

std::error_code mapped_file_region::init(int FD, uint64_t Offset,

                                         mapmode Mode) {

  assert(Size != 0);

  int flags = (Mode == readwrite) ? MAP_SHARED : MAP_PRIVATE;

  int prot = (Mode == readonly) ? PROT_READ : (PROT_READ | PROT_WRITE);

  Mapping = ::mmap(nullptr, Size, prot, flags, FD, Offset);

  if (Mapping == MAP_FAILED)

    return std::error_code(errno, std::generic_category());

  return std::error_code();

}

mapped_file_region::mapped_file_region(int fd, mapmode mode, uint64_t length,

                                       uint64_t offset, std::error_code &ec)

    : Size(length), Mapping() {

  // Make sure that the requested size fits within SIZE_T.

  if (length > std::numeric_limits<size_t>::max()) {

    ec = make_error_code(errc::invalid_argument);

    return;

  }

  ec = init(fd, offset, mode);

  if (ec)

    Mapping = nullptr;

}

mapped_file_region::~mapped_file_region() {

  if (Mapping)

    ::munmap(Mapping, Size);

}

uint64_t mapped_file_region::size() const {

  assert(Mapping && "Mapping failed but used anyway!");

  return Size;

}

char *mapped_file_region::data() const {

  assert(Mapping && "Mapping failed but used anyway!");

  return reinterpret_cast<char*>(Mapping);

}

const char *mapped_file_region::const_data() const {

  assert(Mapping && "Mapping failed but used anyway!");

  return reinterpret_cast<const char*>(Mapping);

}

int mapped_file_region::alignment() {

  return 4096;

}

std::error_code detail::directory_iterator_construct(detail::DirIterState &it,

                                                StringRef path){

  SmallString<128> path_null(path);

  DIR *directory = ::opendir(path_null.c_str());

  if (!directory)

    return std::error_code(errno, std::generic_category());

  it.IterationHandle = reinterpret_cast<intptr_t>(directory);

  // Add something for replace_filename to replace.

  path::append(path_null, ".");

  it.CurrentEntry = directory_entry(path_null.str());

  return directory_iterator_increment(it);

}

std::error_code detail::directory_iterator_destruct(detail::DirIterState &it) {

  if (it.IterationHandle)

    ::closedir(reinterpret_cast<DIR *>(it.IterationHandle));

  it.IterationHandle = 0;

  it.CurrentEntry = directory_entry();

  return std::error_code();

}

std::error_code detail::directory_iterator_increment(detail::DirIterState &it) {

  errno = 0;

  dirent *cur_dir = ::readdir(reinterpret_cast<DIR *>(it.IterationHandle));

  if (cur_dir == nullptr && errno != 0) {

    return std::error_code(errno, std::generic_category());

  } else if (cur_dir != nullptr) {

    StringRef name(cur_dir->d_name, NAMLEN(cur_dir));

    if ((name.size() == 1 && name[0] == '.') ||

        (name.size() == 2 && name[0] == '.' && name[1] == '.'))

      return directory_iterator_increment(it);

    it.CurrentEntry.replace_filename(name);

  } else

    return directory_iterator_destruct(it);

  return std::error_code();

}

std::error_code openFileForRead(const Twine &Name, int &ResultFD) {

  SmallString<128> Storage;

  StringRef P = Name.toNullTerminatedStringRef(Storage);

  while ((ResultFD = open(P.begin(), O_RDONLY)) < 0) {

    if (errno != EINTR)

      return std::error_code(errno, std::generic_category());

  }

  return std::error_code();

}

std::error_code openFileForWrite(const Twine &Name, int &ResultFD,

                            sys::fs::OpenFlags Flags, unsigned Mode) {

  // Verify that we don't have both "append" and "excl".

  assert((!(Flags & sys::fs::F_Excl) || !(Flags & sys::fs::F_Append)) &&

         "Cannot specify both 'excl' and 'append' file creation flags!");

  int OpenFlags = O_CREAT;

  if (Flags & F_RW)

    OpenFlags |= O_RDWR;

  else

    OpenFlags |= O_WRONLY;

  if (Flags & F_Append)

    OpenFlags |= O_APPEND;

  else

    OpenFlags |= O_TRUNC;

  if (Flags & F_Excl)

    OpenFlags |= O_EXCL;

  SmallString<128> Storage;

  StringRef P = Name.toNullTerminatedStringRef(Storage);

  while ((ResultFD = open(P.begin(), OpenFlags, Mode)) < 0) {

    if (errno != EINTR)

      return std::error_code(errno, std::generic_category());

  }

  return std::error_code();

}

} // end namespace fs

namespace path {

bool home_directory(SmallVectorImpl<char> &result) {

  if (char *RequestedDir = getenv("HOME")) {

    result.clear();

    result.append(RequestedDir, RequestedDir + strlen(RequestedDir));

    return true;

  }

  return false;

}

static bool getDarwinConfDir(bool TempDir, SmallVectorImpl<char> &Result) {

  #if defined(_CS_DARWIN_USER_TEMP_DIR) && defined(_CS_DARWIN_USER_CACHE_DIR)

  // On Darwin, use DARWIN_USER_TEMP_DIR or DARWIN_USER_CACHE_DIR.

  // macros defined in <unistd.h> on darwin >= 9

  int ConfName = TempDir ? _CS_DARWIN_USER_TEMP_DIR

                         : _CS_DARWIN_USER_CACHE_DIR;

  size_t ConfLen = confstr(ConfName, nullptr, 0);

  if (ConfLen > 0) {

    do {

      Result.resize(ConfLen);

      ConfLen = confstr(ConfName, Result.data(), Result.size());

    } while (ConfLen > 0 && ConfLen != Result.size());

    if (ConfLen > 0) {

      assert(Result.back() == 0);

      Result.pop_back();

      return true;

    }

    Result.clear();

  }

  #endif

  return false;

}

static bool getUserCacheDir(SmallVectorImpl<char> &Result) {

  // First try using XDS_CACHE_HOME env variable,

  // as specified in XDG Base Directory Specification at

  // http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html

  if (const char *XdsCacheDir = std::getenv("XDS_CACHE_HOME")) {

    Result.clear();

    Result.append(XdsCacheDir, XdsCacheDir + strlen(XdsCacheDir));

    return true;

  }

  // Try Darwin configuration query

  if (getDarwinConfDir(false, Result))

    return true;

  // Use "$HOME/.cache" if $HOME is available

  if (home_directory(Result)) {

    append(Result, ".cache");

    return true;

  }

  return false;

}

static const char *getEnvTempDir() {

  // Check whether the temporary directory is specified by an environment

  // variable.

  const char *EnvironmentVariables[] = {"TMPDIR", "TMP", "TEMP", "TEMPDIR"};

  for (const char *Env : EnvironmentVariables) {

    if (const char *Dir = std::getenv(Env))

      return Dir;

  }

  return nullptr;

}

static const char *getDefaultTempDir(bool ErasedOnReboot) {

#ifdef P_tmpdir

  if ((bool)P_tmpdir)

    return P_tmpdir;

#endif

  if (ErasedOnReboot)

    return "/tmp";

  return "/var/tmp";

}

void system_temp_directory(bool ErasedOnReboot, SmallVectorImpl<char> &Result) {

  Result.clear();

  if (ErasedOnReboot) {

    // There is no env variable for the cache directory.

    if (const char *RequestedDir = getEnvTempDir()) {

      Result.append(RequestedDir, RequestedDir + strlen(RequestedDir));

      return;

    }

  }

  if (getDarwinConfDir(ErasedOnReboot, Result))

    return;

  const char *RequestedDir = getDefaultTempDir(ErasedOnReboot);

  Result.append(RequestedDir, RequestedDir + strlen(RequestedDir));

}

} // end namespace path

} // end namespace sys

} // end namespace llvm_ks