lib/classpath.c

/* Java CLASSPATH handling.
   Copyright (C) 2001-2003, 2006, 2009-2026 Free Software Foundation, Inc.
   Written by Bruno Haible <haible@clisp.cons.org>, 2001.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   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 for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* If CLASSPATHVAR is defined, this file is being #included, and config.h is
   therefore already included.  */
#if !defined CLASSPATHVAR
# include <config.h>
#endif

/* Specification.  */
#include "classpath.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "xsetenv.h"
#include "xalloc.h"

/* Name of environment variable.  */
#ifndef CLASSPATHVAR
# define CLASSPATHVAR "CLASSPATH"
#endif

/* Separator in PATH like lists of pathnames.  */
#if (defined _WIN32 && !defined __CYGWIN__) || defined __EMX__ || defined __DJGPP__
  /* Native Windows, OS/2, DOS */
# define PATH_SEPARATOR ';'
#else
  /* Unix */
# define PATH_SEPARATOR ':'
#endif

/* Return the new CLASSPATH value.  The given classpaths are prepended to
   the current CLASSPATH value.   If use_minimal_classpath, the current
   CLASSPATH is ignored.  */
char *
new_classpath (const char * const *classpaths, unsigned int classpaths_count,
               bool use_minimal_classpath)
{
  const char *old_classpath = (use_minimal_classpath ? NULL : getenv (CLASSPATHVAR));
  if (old_classpath == NULL)
    old_classpath = "";

  unsigned int length = 0;
  for (unsigned int i = 0; i < classpaths_count; i++)
    length += strlen (classpaths[i]) + 1;
  length += strlen (old_classpath);
  if (classpaths_count > 0 && old_classpath[0] == '\0')
    length--;

  char *result = XNMALLOC (length + 1, char);
  {
    char *p = result;
    for (unsigned int i = 0; i < classpaths_count; i++)
      {
        memcpy (p, classpaths[i], strlen (classpaths[i]));
        p += strlen (classpaths[i]);
        *p++ = PATH_SEPARATOR;
      }
    if (old_classpath[0] != '\0')
      {
        memcpy (p, old_classpath, strlen (old_classpath));
        p += strlen (old_classpath);
      }
    else
      {
        if (classpaths_count > 0)
          p--;
      }
    *p = '\0';
  }

  return result;
}

/* Set CLASSPATH and returns a safe copy of its old value.  */
char *
set_classpath (const char * const *classpaths, unsigned int classpaths_count,
               bool use_minimal_classpath, bool verbose)
{
  const char *old_CLASSPATH = getenv (CLASSPATHVAR);
  char *result = (old_CLASSPATH != NULL ? xstrdup (old_CLASSPATH) : NULL);
  char *new_CLASSPATH =
    new_classpath (classpaths, classpaths_count, use_minimal_classpath);

  if (verbose)
    printf (CLASSPATHVAR "=%s ", new_CLASSPATH);

  xsetenv (CLASSPATHVAR, new_CLASSPATH, 1);

  free (new_CLASSPATH);

  return result;
}

/* Restore CLASSPATH to its previous value.  */
void
reset_classpath (char *old_classpath)
{
  if (old_classpath != NULL)
    {
      xsetenv (CLASSPATHVAR, old_classpath, 1);
      free (old_classpath);
    }
  else
    unsetenv (CLASSPATHVAR);
}