/* Copyright (c) 2000, 2024, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is designed to work with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have either included with
   the program or referenced in the documentation.

   Without limiting anything contained in the foregoing, this file,
   which is part of C Driver for MySQL (Connector/C), is also subject to the
   Universal FOSS Exception, version 1.0, a copy of which can be found at
   http://oss.oracle.com/licenses/universal-foss-exception.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA.
*/

/**
  @file mysys/my_lib.cc
*/

/* TODO: check for overrun of memory for names. */

#include <errno.h>
#include <string.h>
#include <sys/stat.h>
#include <algorithm>
#include <memory>
#include <new>

#include "m_string.h"
#include "my_alloc.h"
#include "my_dbug.h"
#include "my_dir.h" /* Structs used by my_dir,includes sys/types */
#include "my_inttypes.h"
#include "my_io.h"
#include "my_pointer_arithmetic.h"
#include "my_sys.h"
#include "my_thread_local.h"
#include "mysql/service_mysql_alloc.h"
#include "mysys/mysys_priv.h"
#include "mysys_err.h"
#include "prealloced_array.h"
#include "template_utils.h"
#if !defined(_WIN32)
#include <dirent.h>
#endif

/*
  Allocate space for 100 FILEINFO structs up-front.
*/
typedef Prealloced_array<FILEINFO, 100> Entries_array;

#define NAMES_START_SIZE 32768

/* We need this because program don't know with malloc we used */

void my_dirend(MY_DIR *buffer) {
  DBUG_TRACE;
  if (buffer != nullptr) {
    Entries_array *array = pointer_cast<Entries_array *>(
        pointer_cast<char *>(buffer) + ALIGN_SIZE(sizeof(MY_DIR)));
    array->~Entries_array();
    ::destroy_at(pointer_cast<MEM_ROOT *>(pointer_cast<char *>(buffer) +
                                          ALIGN_SIZE(sizeof(MY_DIR)) +
                                          ALIGN_SIZE(sizeof(Entries_array))));
    my_free(buffer);
  }
} /* my_dirend */

#if !defined(_WIN32)

static char *directory_file_name(char *dst, const char *src);

MY_DIR *my_dir(const char *path, myf MyFlags) {
  char *buffer;
  MY_DIR *result = nullptr;
  FILEINFO finfo;
  Entries_array *dir_entries_storage;
  MEM_ROOT *names_storage;
  DIR *dirp;
  char tmp_path[FN_REFLEN + 2], *tmp_file;
  void *rawmem = nullptr;

  DBUG_TRACE;
  DBUG_PRINT("my", ("path: '%s' MyFlags: %d", path, MyFlags));

  dirp = opendir(directory_file_name(tmp_path, path));
  if (dirp == nullptr ||
      !(buffer = static_cast<char *>(
            my_malloc(key_memory_MY_DIR,
                      ALIGN_SIZE(sizeof(MY_DIR)) +
                          ALIGN_SIZE(sizeof(Entries_array)) + sizeof(MEM_ROOT),
                      MyFlags))))
    goto error;

  rawmem = pointer_cast<Entries_array *>(buffer + ALIGN_SIZE(sizeof(MY_DIR)));
  dir_entries_storage = new (rawmem) Entries_array(key_memory_MY_DIR);
  names_storage = new (buffer + ALIGN_SIZE(sizeof(MY_DIR)) +
                       ALIGN_SIZE(sizeof(Entries_array)))
      MEM_ROOT(key_memory_MY_DIR, NAMES_START_SIZE);
  ;
  /* MY_DIR structure is allocated and completely initialized at this point */
  result = (MY_DIR *)buffer;

  tmp_file = strend(tmp_path);

  for (const dirent *dp = readdir(dirp); dp; dp = readdir(dirp)) {
    if (!(finfo.name = strdup_root(names_storage, dp->d_name))) goto error;

    if (MyFlags & MY_WANT_STAT) {
      if (!(finfo.mystat = (MY_STAT *)names_storage->Alloc(sizeof(MY_STAT))))
        goto error;

      memset(finfo.mystat, 0, sizeof(MY_STAT));
      (void)my_stpcpy(tmp_file, dp->d_name);
      (void)my_stat(tmp_path, finfo.mystat, MyFlags);
      if (!(finfo.mystat->st_mode & MY_S_IREAD)) continue;
    } else
      finfo.mystat = nullptr;

    if (dir_entries_storage->push_back(finfo)) goto error;
  }

  (void)closedir(dirp);

  result->dir_entry = dir_entries_storage->begin();
  result->number_off_files = dir_entries_storage->size();

  if (!(MyFlags & MY_DONT_SORT))
    std::sort(result->dir_entry, result->dir_entry + result->number_off_files,
              [](const fileinfo &a, const fileinfo &b) {
                return strcmp(a.name, b.name) < 0;
              });
  return result;

error:
  set_my_errno(errno);
  if (dirp) (void)closedir(dirp);
  my_dirend(result);
  if (MyFlags & (MY_FAE | MY_WME)) {
    MyOsError(my_errno(), EE_DIR, MYF(0), path);
  }
  return nullptr;
}

/*
 * Convert from directory name to filename.
 * On UNIX, it's simple: just make sure there is a terminating /

 * Returns pointer to dst;
 */

static char *directory_file_name(char *dst, const char *src) {
  /* Process as Unix format: just remove test the final slash. */
  char *end;
  assert(strlen(src) < (FN_REFLEN + 1));

  if (src[0] == 0) src = "."; /* Use empty as current */
  end = my_stpnmov(dst, src, FN_REFLEN + 1);
  if (end[-1] != FN_LIBCHAR) {
    end[0] = FN_LIBCHAR; /* Add last '/' */
    end[1] = '\0';
  }
  return dst;
}

#else

/*
*****************************************************************************
** Read long filename using windows rutines
*****************************************************************************
*/

MY_DIR *my_dir(const char *path, myf MyFlags) {
  char *buffer;
  MY_DIR *result = nullptr;
  FILEINFO finfo;
  Entries_array *dir_entries_storage;
  MEM_ROOT *names_storage;
  struct _finddata_t find;
  ushort mode;
  char tmp_path[FN_REFLEN], *tmp_file, attrib;
  __int64 handle = -1;
  void *rawmem = nullptr;

  DBUG_TRACE;
  DBUG_PRINT("my", ("path: '%s' MyFlags: %d", path, MyFlags));

  /* Put LIB-CHAR as last path-character if not there */
  tmp_file = tmp_path;
  if (!*path) *tmp_file++ = '.'; /* From current dir */
  tmp_file = my_stpnmov(tmp_file, path, FN_REFLEN - 5);
  if (tmp_file[-1] == FN_DEVCHAR) *tmp_file++ = '.'; /* From current dev-dir */
  if (tmp_file[-1] != FN_LIBCHAR) *tmp_file++ = FN_LIBCHAR;
  tmp_file[0] = '*'; /* Windows needs this !??? */
  tmp_file[1] = '.';
  tmp_file[2] = '*';
  tmp_file[3] = '\0';

  if (!(buffer = static_cast<char *>(
            my_malloc(key_memory_MY_DIR,
                      ALIGN_SIZE(sizeof(MY_DIR)) +
                          ALIGN_SIZE(sizeof(Entries_array)) + sizeof(MEM_ROOT),
                      MyFlags))))
    goto error;

  rawmem = buffer + ALIGN_SIZE(sizeof(MY_DIR));
  dir_entries_storage = new (rawmem) Entries_array(key_memory_MY_DIR);
  names_storage = new (buffer + ALIGN_SIZE(sizeof(MY_DIR)) +
                       ALIGN_SIZE(sizeof(Entries_array)))
      MEM_ROOT(key_memory_MY_DIR, NAMES_START_SIZE);

  /* MY_DIR structure is allocated and completely initialized at this point */
  result = (MY_DIR *)buffer;

  if ((handle = _findfirst(tmp_path, &find)) == -1L) {
    DBUG_PRINT("info", ("findfirst returned error, errno: %d", errno));
    if (errno != EINVAL) goto error;
    /*
      Could not read the directory, no read access.
      Probably because by "chmod -r".
      continue and return zero files in dir
    */
  } else {
    do {
      attrib = find.attrib;
      /*
        Do not show hidden and system files which Windows sometimes create.
        Note. Because Borland's findfirst() is called with the third
        argument = 0 hidden/system files are excluded from the search.
      */
      if (attrib & (_A_HIDDEN | _A_SYSTEM)) continue;
      if (!(finfo.name = strdup_root(names_storage, find.name))) goto error;
      if (MyFlags & MY_WANT_STAT) {
        if (!(finfo.mystat = (MY_STAT *)names_storage->Alloc(sizeof(MY_STAT))))
          goto error;

        memset(finfo.mystat, 0, sizeof(MY_STAT));
        finfo.mystat->st_size = find.size;
        mode = MY_S_IREAD;
        if (!(attrib & _A_RDONLY)) mode |= MY_S_IWRITE;
        if (attrib & _A_SUBDIR) mode |= MY_S_IFDIR;
        finfo.mystat->st_mode = mode;
        finfo.mystat->st_mtime = ((uint32)find.time_write);
      } else
        finfo.mystat = nullptr;

      if (dir_entries_storage->push_back(finfo)) goto error;
    } while (_findnext(handle, &find) == 0);

    _findclose(handle);
  }

  result->dir_entry = dir_entries_storage->begin();
  result->number_off_files = dir_entries_storage->size();

  if (!(MyFlags & MY_DONT_SORT))
    std::sort(result->dir_entry, result->dir_entry + result->number_off_files,
              [](const fileinfo &a, const fileinfo &b) {
                return strcmp(a.name, b.name) < 0;
              });
  DBUG_PRINT("exit", ("found %d files", result->number_off_files));
  return result;
error:
  set_my_errno(errno);
  if (handle != -1) _findclose(handle);
  my_dirend(result);
  if (MyFlags & (MY_FAE | MY_WME)) {
    MyOsError(my_errno(), EE_DIR, MYF(0), path);
  }
  return nullptr;
}

#endif /* _WIN32 */

/****************************************************************************
** File status
** Note that MY_STAT is assumed to be same as struct stat
****************************************************************************/

int my_fstat(File Filedes, MY_STAT *stat_area) {
  DBUG_TRACE;
  DBUG_PRINT("my", ("fd: %d", Filedes));
#ifdef _WIN32
  return my_win_fstat(Filedes, stat_area);
#else
  return fstat(Filedes, stat_area);
#endif
}

MY_STAT *my_stat(const char *path, MY_STAT *stat_area, myf MyFlags) {
  DBUG_TRACE;
  assert(stat_area != nullptr);
  DBUG_PRINT("my", ("path: '%s'  stat_area: %p  MyFlags: %d", path, stat_area,
                    MyFlags));

#ifndef _WIN32
  if (!stat(path, stat_area)) return stat_area;
#else
  if (!my_win_stat(path, stat_area)) return stat_area;
#endif

  DBUG_PRINT("error", ("Got errno: %d from stat", errno));
  set_my_errno(errno);

  if (MyFlags & (MY_FAE | MY_WME)) {
    MyOsError(my_errno(), EE_STAT, MYF(0), path);
  }
  return nullptr;
}