/* Program name management.

   Copyright (C) 2001-2003, 2005-2020 Free Software Foundation, Inc.

   Written by Bruno Haible <bruno@clisp.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/>.  */

#include <config.h>

/* Specification.  */

#undef ENABLE_RELOCATABLE /* avoid defining set_program_name as a macro */

#include "progname.h"

#include <errno.h> /* get program_invocation_name declaration */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

/* String containing name the program is called with.

   To be initialized by main().  */

const char *program_name = NULL;

/* Set program_name, based on argv[0].

   argv0 must be a string allocated with indefinite extent, and must not be

   modified after this call.  */

void

set_program_name (const char *argv0)

{

  /* libtool creates a temporary executable whose name is sometimes prefixed

     with "lt-" (depends on the platform).  It also makes argv[0] absolute.

     But the name of the temporary executable is a detail that should not be

     visible to the end user and to the test suite.

     Remove this "<dirname>/.libs/" or "<dirname>/.libs/lt-" prefix here.  */

  const char *slash;

  const char *base;

  /* Sanity check.  POSIX requires the invoking process to pass a non-NULL

     argv[0].  */

  if (argv0 == NULL)

    {

      /* It's a bug in the invoking program.  Help diagnosing it.  */

      fputs ("A NULL argv[0] was passed through an exec system call.\n",

             stderr);

      abort ();

    }

  slash = strrchr (argv0, '/');

  base = (slash != NULL ? slash + 1 : argv0);

  if (base - argv0 >= 7 && strncmp (base - 7, "/.libs/", 7) == 0)

    {

      argv0 = base;

      if (strncmp (base, "lt-", 3) == 0)

        {

          argv0 = base + 3;

          /* On glibc systems, remove the "lt-" prefix from the variable

             program_invocation_short_name.  */

#if HAVE_DECL_PROGRAM_INVOCATION_SHORT_NAME

          program_invocation_short_name = (char *) argv0;

#endif

        }

    }

  /* But don't strip off a leading <dirname>/ in general, because when the user

     runs

         /some/hidden/place/bin/cp foo foo

     he should get the error message

         /some/hidden/place/bin/cp: `foo' and `foo' are the same file

     not

         cp: `foo' and `foo' are the same file

   */

  program_name = argv0;

  /* On glibc systems, the error() function comes from libc and uses the

     variable program_invocation_name, not program_name.  So set this variable

     as well.  */

#if HAVE_DECL_PROGRAM_INVOCATION_NAME

  program_invocation_name = (char *) argv0;

#endif

}