/* 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/mf_path.cc
*/

#include "my_config.h"

#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include "m_string.h"
#include "my_dbug.h"
#include "my_inttypes.h"
#include "my_io.h"
#include "my_sys.h"
#include "mysys/my_static.h"
#include "nulls.h"
#include "strxmov.h"

static char *find_file_in_path(char *to, const char *name);

/* Finds where program can find it's files.
   pre_pathname is found by first locking at progname (argv[0]).
   if progname contains path the path is returned.
   else if progname is found in path, return it
   else if progname is given and POSIX environment variable "_" is set
   then path is taken from "_".
   If filename doesn't contain a path append MY_BASEDIR_VERSION or
   MY_BASEDIR if defined, else append "/my/running".
   own_path_name_part is concatenated to result.
   my_path puts result in to and returns to */

char *my_path(char *to, const char *progname, const char *own_pathname_part) {
  char *start, *prog;
  const char *end;
  size_t to_length;
  DBUG_TRACE;

  start = to; /* Return this */
  if (progname && (dirname_part(to, progname, &to_length) ||
                   find_file_in_path(to, progname) ||
                   ((prog = getenv("_")) != nullptr &&
                    dirname_part(to, prog, &to_length)))) {
    (void)intern_filename(to, to);
    if (!test_if_hard_path(to)) {
      if (!my_getwd(curr_dir, FN_REFLEN, MYF(0)))
        bchange((uchar *)to, 0, (uchar *)curr_dir, strlen(curr_dir),
                strlen(to) + 1);
    }
  } else {
    if ((end = getenv("MY_BASEDIR_VERSION")) == nullptr &&
        (end = getenv("MY_BASEDIR")) == nullptr) {
#ifdef DEFAULT_BASEDIR
      end = DEFAULT_BASEDIR;
#else
      end = "/my/";
#endif
    }
    (void)intern_filename(to, end);
    to = strend(to);
    if (to != start && to[-1] != FN_LIBCHAR) *to++ = FN_LIBCHAR;
    (void)my_stpcpy(to, own_pathname_part);
  }
  DBUG_PRINT("exit", ("to: '%s'", start));
  return start;
} /* my_path */

/* test if file without filename is found in path */
/* Returns to if found and to has dirpart if found, else NullS */

#if defined(_WIN32)
#define F_OK 0
#define PATH_SEP ';'
#define PROGRAM_EXTENSION ".exe"
#else
#define PATH_SEP ':'
#endif

static char *find_file_in_path(char *to, const char *name) {
  char *path, *pos, dir[2];
  const char *ext = "";

  if (!(path = getenv("PATH"))) return NullS;
  dir[0] = FN_LIBCHAR;
  dir[1] = 0;
#ifdef PROGRAM_EXTENSION
  if (!fn_ext(name)[0]) ext = PROGRAM_EXTENSION;
#endif

  for (pos = path; (pos = strchr(pos, PATH_SEP)); path = ++pos) {
    if (path != pos) {
      strxmov(my_stpnmov(to, path, (uint)(pos - path)), dir, name, ext, NullS);
      if (!access(to, F_OK)) {
        to[(uint)(pos - path) + 1] = 0; /* Return path only */
        return to;
      }
    }
  }
#ifdef _WIN32
  to[0] = FN_CURLIB;
  strxmov(to + 1, dir, name, ext, NullS);
  if (!access(to, F_OK)) /* Test in current dir */
  {
    to[2] = 0; /* Leave ".\" */
    return to;
  }
#endif
  return NullS; /* File not found */
}