glibc/sysdeps/unix/start.c

/* Copyright (C) 1991, 93, 1995-1998, 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <sysdep.h>		/* In case it wants to define anything.  */

/* The first piece of initialized data.  */
int __data_start = 0;
#ifdef HAVE_WEAK_SYMBOLS
weak_alias (__data_start, data_start)
#endif

#ifdef	DUMMIES
#define	ARG_DUMMIES	DUMMIES,
#define	DECL_DUMMIES	int DUMMIES;
#else
#define	ARG_DUMMIES
#define	DECL_DUMMIES
#endif

#ifndef errno
/* __errno must be initialized since otherwise one cannot create an
   alias (at least on some platforms).  */
volatile int __errno = 0;
strong_alias (__errno, errno)
#endif

extern void __libc_init (int argc, char **argv, char **envp);
extern int main (int argc, char **argv, char **envp);


/* Not a prototype because it gets called strangely.  */
static void start1();

#ifndef	HAVE__start

/* N.B.: It is important that this be the first function.
   This file is the first thing in the text section.  */
void
_start ()
{
  start1 ();
}

#ifndef NO_UNDERSCORES
/* Make an alias called `start' (no leading underscore, so it can't
   conflict with C symbols) for `_start'.  This is the name vendor crt0.o's
   tend to use, and thus the name most linkers expect.  */
asm (".set start, __start");
#endif

#endif

/* ARGSUSED */
static void
start1 (ARG_DUMMIES argc, argp)
     DECL_DUMMIES
     int argc;
     char *argp;
{
  char **argv = &argp;

  /* The environment starts just after ARGV.  */
  __environ = &argv[argc + 1];

  /* If the first thing after ARGV is the arguments
     themselves, there is no environment.  */
  if ((char *) __environ == *argv)
    /* The environment is empty.  Make __environ
       point at ARGV[ARGC], which is NULL.  */
    --__environ;

  /* Do C library initializations.  */
  __libc_init (argc, argv, __environ);

  /* Call the user program.  */
  exit (main (argc, argv, __environ));
}